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Sample records for alkali-metal vapor cells

  1. Investigation of Anti-Relaxation Coatings for Alkali-Metal Vapor Cells Using Surface Science Techniques

    CERN Document Server

    Seltzer, S J; Donaldson, M H; Balabas, M V; Barber, S K; Bernasek, S L; Bouchiat, M -A; Hexemer, A; Hibberd, A M; Kimball, D F Jackson; Jaye, C; Karaulanov, T; Narducci, F A; Rangwala, S A; Robinson, H G; Voronov, D L; Yashchuk, V V; Pines, A; Budker, D

    2010-01-01

    Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of anti-relaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10,000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We present a survey of modern surface science techniques applied to the study of paraffin coatings, in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge X-ray absorption fine structure spectroscopy, and X-ray photoelectron spectroscopy. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of C=C double bonds present with...

  2. Investigation of anti-Relaxation coatings for alkali-metal vapor cells using surface science techniques

    Energy Technology Data Exchange (ETDEWEB)

    Seltzer, S. J.; Michalak, D. J.; Donaldson, M. H.; Balabas, M. V.; Barber, S. K.; Bernasek, S. L.; Bouchiat, M.-A.; Hexemer, A.; Hibberd, A. M.; Jackson Kimball, D. F.; Jaye, C.; Karaulanov, T.; Narducci, F. A.; Rangwala, S. A.; Robinson, H. G.; Shmakov, A. K.; Voronov, D. L.; Yashchuk, V. V.; Pines, A.; Budker, D.

    2010-10-11

    Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of antirelaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10?000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge x-ray absorption fine structure spectroscopy, and x-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of C=C double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin antirelaxation coatings, as well as the design and synthesis of new classes of coating materials.

  3. Electric-field-induced change of alkali-metal vapor density in paraffin-coated cells

    CERN Document Server

    Kimball, D F Jackson; Ravi, K; Sharma, Arijit; Prabhudesai, Vaibhav S; Rangwala, S A; Yashchuk, V V; Balabas, M V; Budker, D

    2008-01-01

    Alkali vapor cells with antirelaxation coating (especially paraffin-coated cells) have been a central tool in optical pumping and atomic spectroscopy experiments for 50 years. We have discovered a dramatic change of the alkali vapor density in a paraffin-coated cell upon application of an electric field to the cell. A systematic experimental characterization of the phenomenon is carried out for electric fields ranging in strength from 0-8 kV/cm for paraffin-coated cells containing rubidium and cells containing cesium. The typical response of the vapor density to a rapid (duration < 100 ms) change in electric field of sufficient magnitude includes (a) a rapid (duration of < 100 ms) and significant increase in alkali vapor density followed by (b) a less rapid (duration of ~ 1 s) and significant decrease in vapor density (below the equilibrium vapor density), and then (c) a slow (duration of ~ 100 s) recovery of the vapor density to its equilibrium value. Measurements conducted after the alkali vapor densi...

  4. Magnetometry with millimeter-scale anti-relaxation-coated alkali-metal vapor cells

    CERN Document Server

    Balabas, M V; Kitching, J; Schwindt, P D D; Stalnaker, J E

    2005-01-01

    Dynamic nonlinear magneto-optical-rotation signals with frequency- and amplitude-modulated laser light have been observed and investigated with a spherical glass cell of 3-mm diameter containing Cs metal with inner walls coated with paraffin. Intrinsic Zeeman relaxation rates of $\\gamma/(2\\pi)\\approx 20 $Hz and lower have been observed. Favorable prospects of using millimeter-scale coated cells in portable magnetometers and secondary frequency references are discussed.

  5. 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.

  6. Saturated vapor pressure above the amalgam of alkali metals in discharge lamps

    Science.gov (United States)

    Gavrish, S. V.

    2011-12-01

    A theoretical and numerical analysis of the evaporation process of two-component compounds in vapors of alkali metals in discharge lamps is presented. Based on the developed mathematical model of calculation of saturated vapor pressure of the metal above the amalgam, dependences of mass fractions of the components in the discharge volume on design parameters and thermophysical characteristics of the lamp are obtained.

  7. Saturated vapor pressure over molten mixtures of GaCl3 and alkali metal chlorides

    International Nuclear Information System (INIS)

    Volatilities of GaCl3 and alkali metal chlorides over diluted (up to 3 mol %) solutions of GaCl3 in LiCl, NaCl, KCl, RbCl, and CsCl were measured at 1100 K by dynamic and indirect static methods. Chemical composition of saturated vapor over the mixed melts was determined. Partial pressures of the components were calculated. Their values depend essentially on specific alkali metal cation and on concentration of GaCl3; their variation permits altering parameters of GaCl3 distillation from the salt melt in a wide range

  8. [The Measuring Method of Atomic Polarization of Alkali Metal Vapor Based on Optical Rotation and the Analysis of the Influence Factors].

    Science.gov (United States)

    Shang, Hui-ning; Quan, Wei; Chen, Yao; Li, Yang; Li, Hong

    2016-02-01

    High sensitivity measurements of inertia and magnetic field could be achieved by utilizing a category of devices, which manipulate the atomic spins in the spin-exchange-relaxation-free regime. The alkali cell which contains the alkali metal vapor is used to sense magnetic field and inertia. The atomic number density of alkali vapor and the polarization of alkali metal vapor are two of the most important parameters of the cell. They play an important role in the research on atomic spins in the spin-exchange-relaxation-free regime. Besides, optical polarization plays an important role in quantum computing and atomic physics. We propose a measurement of alkali vapor polarization and alkali number density by detecting the optical rotation in one system. This method simplifies existing experimental equipment and processes. A constant bias magnetic field is applied and the Faraday rotation angle is detected by a bunch of the probe beam to deduce alkali-metal density. Then the magnetic field is closed and a bunch of the pump laser is utilized to polarize alkali-metal. Again, the probe beam is utilized to obtain the polarization of alkali metal. The alkali density obtained at first is used to deduce the polarization. This paper applies a numerical method to analyze the Faraday rotation and the polarization rotation. According to the numerical method, the optimal wavelength for the experiment is given. Finally, the fluctuation of magnetic field and wavelength on signal analysis are analyzed. PMID:27209720

  9. 热煤气中碱金属蒸气的脱除%Removal of Alkali Metal Vapor from Hot Coal Gas

    Institute of Scientific and Technical Information of China (English)

    申文琴; 豆彬林; 邢嵘; 沙兴中

    2000-01-01

    Seven adsorbents were screened for removal of alkali metal vapor from hot coal gas. It is found that five adsorbents present higher adsorption efficiency and activated almmina shows the highest adsorption capacity. The adsorption process of activated alumina is a physical process in experimental condition.%为了清除煤燃烧或气化产生的热气体中的碱金属蒸气,筛选了7种吸附剂,发现5种吸附剂的吸附效率都能达到80%以上,其中活性氧化铝的碱容量最高,对活性氧化铝吸附机理也进行了初步探讨。

  10. AMTEC vapor-vapor series connected cells

    Science.gov (United States)

    Underwood, Mark L.; Williams, Roger M.; Ryan, Margaret A.; Nakamura, Barbara J.; Oconnor, Dennis E.

    1995-08-01

    An alkali metal thermoelectric converter (AMTEC) having a plurality of cells structurally connected in series to form a septum dividing a plenum into two chambers, and electrically connected in series, is provided with porous metal anodes and porous metal cathodes in the cells. The cells may be planar or annular, and in either case a metal alkali vapor at a high temperature is provided to the plenum through one chamber on one side of the wall and returned to a vapor boiler after condensation at a chamber on the other side of the wall in the plenum. If the cells are annular, a heating core may be placed along the axis of the stacked cells. This arrangement of series-connected cells allows efficient generation of power at high voltage and low current.

  11. Process for recovering alkali metals and sulfur from alkali metal sulfides and polysulfides

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, John Howard; Alvare, Javier

    2016-10-25

    Alkali metals and sulfur may be recovered from alkali monosulfide and polysulfides in an electrolytic process that utilizes an electrolytic cell having an alkali ion conductive membrane. An anolyte solution includes an alkali monosulfide, an alkali polysulfide, or a mixture thereof and a solvent that dissolves elemental sulfur. A catholyte includes molten alkali metal. Applying an electric current oxidizes sulfide and polysulfide in the anolyte compartment, causes alkali metal ions to pass through the alkali ion conductive membrane to the catholyte compartment, and reduces the alkali metal ions in the catholyte compartment. Liquid sulfur separates from the anolyte solution and may be recovered. The electrolytic cell is operated at a temperature where the formed alkali metal and sulfur are molten.

  12. Methods of recovering alkali metals

    Science.gov (United States)

    Krumhansl, James L; Rigali, Mark J

    2014-03-04

    Approaches for alkali metal extraction, sequestration and recovery are described. For example, a method of recovering alkali metals includes providing a CST or CST-like (e.g., small pore zeolite) material. The alkali metal species is scavenged from the liquid mixture by the CST or CST-like material. The alkali metal species is extracted from the CST or CST-like material.

  13. Upgrading platform using alkali metals

    Science.gov (United States)

    Gordon, John Howard

    2014-09-09

    A process for removing sulfur, nitrogen or metals from an oil feedstock (such as heavy oil, bitumen, shale oil, etc.) The method involves reacting the oil feedstock with an alkali metal and a radical capping substance. The alkali metal reacts with the metal, sulfur or nitrogen content to form one or more inorganic products and the radical capping substance reacts with the carbon and hydrogen content to form a hydrocarbon phase. The inorganic products may then be separated out from the hydrocarbon phase.

  14. Corrosion by the Alkali Metals

    International Nuclear Information System (INIS)

    This is a review of the state of the art of corrosion testing of materials by the alkali metals, the models proposed to explain the observed corrosion results, and the status of materials selection for application in alkali metal-cooled systems. Corrosion of structural and fuel cladding materials by liquid Na and NaK has been studied intensively, but intermittently for the last 18 years. These studies and the liquid-metal-cooled reactors in operation demonstrate that stainless steels can be considered for structural and cladding applications below 650°C. Above this temperature increased corrosion and radiation-induced embrittlement make them unsatisfactory. Corrosion models are reviewed and their inability to explain all the experimental observations discussed. An alternate model is proposed which qualitatively is in agreement with experimental observations. In this model, the rate-controlling step is either the surface reaction of Fe with ''available oxygen'' (dissolved Na2O) to form an Fe-O-Na complex or the rate at which ''available oxygen'' can reach the surface to form the complex; which process is rate controlling depends on the temperature, Na velocity and oxygen concentration in the Na. The solution chemistry of oxygen, carbon and alkali metal-oxygen-transition metal complexes dissolved in the alkali metals is reviewed. ''Molecular'' complexes appear unlikely to exist in solution in the alkali metals, although the thermodynamic tendencies for them to form suggest that stable bonds exist in solution between oxygen, the transition and the alkali metals. The insolubility of carbon in ''oxygen-free'' sodium indicates that carbon transfer may be associated with oxygen in sodium down to very low oxygen levels, although experimental data do not generally confirm this postulate. Corrosion of refractory metals by boiling alkali metals at temperatures above 1000°C is markedly affected by impurities in either the liquid or refractory metal; the addition of Ti, Zr or

  15. Alkali-metal intercalation in carbon nanotubes

    Science.gov (United States)

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

    1999-09-01

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

  16. Cathode architectures for alkali metal / oxygen batteries

    Energy Technology Data Exchange (ETDEWEB)

    Visco, Steven J; Nimon, Vitaliy; De Jonghe, Lutgard C; Volfkovich, Yury; Bograchev, Daniil

    2015-01-13

    Electrochemical energy storage devices, such as alkali metal-oxygen battery cells (e.g., non-aqueous lithium-air cells), have a cathode architecture with a porous structure and pore composition that is tailored to improve cell performance, especially as it pertains to one or more of the discharge/charge rate, cycle life, and delivered ampere-hour capacity. A porous cathode architecture having a pore volume that is derived from pores of varying radii wherein the pore size distribution is tailored as a function of the architecture thickness is one way to achieve one or more of the aforementioned cell performance improvements.

  17. Electrodes For Alkali-Metal Thermoelectric Converters

    Science.gov (United States)

    Williams, Roger M.; Wheeler, Bob L.; Jeffries-Nakamura, Barbara; Lamb, James L.; Bankston, C. Perry; Cole, Terry

    1989-01-01

    Combination of thin, porous electrode and overlying collector grid reduces internal resistance of alkali-metal thermoelectric converter cell. Low resistance of new electrode and grid boosts power density nearly to 1 W/cm2 of electrode area at typical operating temperatures of 1,000 to 1,300 K. Conductive grid encircles electrode film on alumina tube. Bus wire runs along tube to collect electrical current from grid. Such converters used to transform solar, nuclear, and waste heat into electric power.

  18. The development of a potassium-sulfide glass fiber cell and studies on impurities in alkali metal-sulfur cells

    Science.gov (United States)

    Tsang, F. Y.

    1977-01-01

    Potassium sulfur rechargeable cells, having as the electrolyte the thin walls of hollow glass fibers made from permeable glass, were developed. The cells had short lives, probably due to the construction materials and impurities in the potassium. The effect of the impurities in the analogous NA-S system was studied. Calcium, potassium, and NaOH/oxide impurities caused increased resistance or corrosion of the glass fibers. For long lived cell operation, the Na must contain less than 1 ppm Ca and less than a few ppm of hydroxide/oxide. Up to 150 ppm K can be tolerated. After purification of the Na anolyte, cell lifetimes in excess of 1000 deep charge-discharge cycles or over 8 months on continuous cycling at 10-30 percent depth of discharge were obtained.

  19. I3-/I- Redox Behavior of Alkali-metal Iodide Complexes with Crown Ether/Cryptand Macrocycles and Their Applications to Dye-sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    史成武; 戴松元; 王孔嘉; 潘旭; 郭力; 胡林华; 孔凡太

    2005-01-01

    In this article, the I3-/I- redox behavior in 3-methoxypropionitrile (MePN) containing alkali-metal iodide complexes with crown ether and crypt,and macrocycles was studied by cyclic voltammetry. It was found that the apparent diffusion coefficient D values of triiodide and iodide ions correlate with cations. D values of triiodide follow the order: 1,2-dimethyl-3-propylimidazolium cation (DMPI+)>[Na belong to 15-C-5]+ (the mathematical symbol of inclus ions belong to, was used to indicate Na+ included in 15-C-5)> [K belong to 18-C-6]+> [Na belog to 2.2.1-cryptand]+ and those of iodide ionsfollow the order: [Na belong to 2.2.1-cryptand]+ > [Na belong to 15-C-5]+≈[K belong to 18-C-6]+ > DMPI+. The photovoltaic performances of dye-sensitized solar cells (DSC) with these complexes were compared with those containing 1,2-dimethyl-3-propylimidazolium iodide (DMPII) in MePN. It shows that DSC with these complexes gave a little higher short photocurrent intensity and lower fill factor than those with DMPII, which is consistent with D values of triiodide and iodide ions. Moreover, solvents played an important role for the photo-electric conversion efficiency of DSC. The photo-electric conversion efficiency of DSC with DMPII is higher than that with [K belong to 18-C-6]I in MePN, while in ACN, it shows a little difference.

  20. Recovery of alkali metal constituents from catalytic coal conversion residues

    Science.gov (United States)

    Soung, W.Y.

    In a coal gasification operation (32) or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein particles containing alkali metal residues are produced, alkali metal constituents are recovered from the particles by contacting them with water or an aqueous solution to remove water-soluble alkali metal constituents and produce an aqueous solution enriched in said constituents. The aqueous solution thus produced is then contacted with carbon dioxide to precipitate silicon constituents, the pH of the resultant solution is increased, preferably to a value in the range between about 12.5 and about 15.0, and the solution of increased pH is evaporated to increase the alkali metal concentration. The concentrated aqueous solution is then recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

  1. Alkali metals in fungi of forest soil

    International Nuclear Information System (INIS)

    The high affinity of forest soil fungi for alkali metals such as potassium, rubidium, caesium as well as radiocaesium is shown and discussed. Good positive correlation was found between K: Rb concentration ratios in soil and in fungi, when correlation between K: Cs concentration ratios was less pronounced. (LN)

  2. Spin-polarized lithium diffusion in a glass hot-vapor cell

    Science.gov (United States)

    Ishikawa, Kiyoshi

    2016-08-01

    We report diffusion coefficients of optically pumped lithium atoms in helium buffer gas. The free-induction decay and the spin-echo signals of ground-state atoms were optically detected in an external magnetic field with the addition of field gradient. Lithium hot vapor was produced in a borosilicate-glass cell at a temperature between 290 and 360°C. The simple setup using the glass cells enabled lithium atomic spectroscopy in a similar way to other alkali-metal atoms and study of the collisional properties of lithium atoms in a hot-vapor phase.

  3. 40 CFR 721.4660 - Alcohol, alkali metal salt.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alcohol, alkali metal salt. 721.4660... Substances § 721.4660 Alcohol, alkali metal salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as alcohol, alkali metal salt (PMN P-91-151)...

  4. Superconductivity in alkali metal intercalated iron selenides

    Science.gov (United States)

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

    2016-07-01

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

  5. COMPLEX FLUORIDES OF PLUTONIUM AND AN ALKALI METAL

    Science.gov (United States)

    Seaborg, G.T.

    1960-08-01

    A method is given for precipitating alkali metal plutonium fluorides. such as KPuF/sub 5/, KPu/sub 2/F/sub 9/, NaPuF/sub 5/, and RbPuF/sub 5/, from an aqueous plutonium(IV) solution by adding hydrogen fluoride and alkali-metal- fluoride.

  6. High-Order Dispersion Coefficients for Alkali-metal Atoms

    Institute of Scientific and Technical Information of China (English)

    KANG Shuai; DING Chi-Kun; CHEN Chang-Yong; WU Xue-Qing

    2013-01-01

    High-order dispersion coefficients C9,C11,C12,and C13 for the ground-state alkali-metals were calculated by combining the l-dependent model potential of alkali-metal atoms and linear variation method based on B-spline basis functions.The results were compared.

  7. Bioinorganic Chemistry of the Alkali Metal Ions.

    Science.gov (United States)

    Kim, Youngsam; Nguyen, Thuy-Tien T; Churchill, David G

    2016-01-01

    The common Group 1 alkali metals are indeed ubiquitous on earth, in the oceans and in biological systems. In this introductory chapter, concepts involving aqueous chemistry and aspects of general coordination chemistry and oxygen atom donor chemistry are introduced. Also, there are nuclear isotopes of importance. A general discussion of Group 1 begins from the prevalence of the ions, and from a comparison of their ionic radii and ionization energies. While oxygen and water molecule binding have the most relevance to biology and in forming a detailed understanding between the elements, there is a wide range of basic chemistry that is potentially important, especially with respect to biological chelation and synthetic multi-dentate ligand design. The elements are widely distributed in life forms, in the terrestrial environment and in the oceans. The details about the workings in animal, as well as plant life are presented in this volume. Important biometallic aspects of human health and medicine are introduced as well. Seeing as the elements are widely present in biology, various particular endogenous molecules and enzymatic systems can be studied. Sodium and potassium are by far the most important and central elements for consideration. Aspects of lithium, rubidium, cesium and francium chemistry are also included; they help in making important comparisons related to the coordination chemistry of Na(+) and K(+). Physical methods are also introduced. PMID:26860297

  8. Bioinorganic Chemistry of the Alkali Metal Ions.

    Science.gov (United States)

    Kim, Youngsam; Nguyen, Thuy-Tien T; Churchill, David G

    2016-01-01

    The common Group 1 alkali metals are indeed ubiquitous on earth, in the oceans and in biological systems. In this introductory chapter, concepts involving aqueous chemistry and aspects of general coordination chemistry and oxygen atom donor chemistry are introduced. Also, there are nuclear isotopes of importance. A general discussion of Group 1 begins from the prevalence of the ions, and from a comparison of their ionic radii and ionization energies. While oxygen and water molecule binding have the most relevance to biology and in forming a detailed understanding between the elements, there is a wide range of basic chemistry that is potentially important, especially with respect to biological chelation and synthetic multi-dentate ligand design. The elements are widely distributed in life forms, in the terrestrial environment and in the oceans. The details about the workings in animal, as well as plant life are presented in this volume. Important biometallic aspects of human health and medicine are introduced as well. Seeing as the elements are widely present in biology, various particular endogenous molecules and enzymatic systems can be studied. Sodium and potassium are by far the most important and central elements for consideration. Aspects of lithium, rubidium, cesium and francium chemistry are also included; they help in making important comparisons related to the coordination chemistry of Na(+) and K(+). Physical methods are also introduced.

  9. Hall Determination of Atomic Radii of Alkali Metals

    Science.gov (United States)

    Houari, Ahmed

    2008-01-01

    I will propose here an alternative method for determining atomic radii of alkali metals based on the Hall measurements of their free electron densities and the knowledge of their crystal structure. (Contains 2 figures.)

  10. Two-phase alkali-metal experiments in reduced gravity

    Energy Technology Data Exchange (ETDEWEB)

    Antoniak, Z.I.

    1986-06-01

    Future space missions envision the use of large nuclear reactors utilizing either a single or a two-phase alkali-metal working fluid. The design and analysis of such reactors require state-of-the-art computer codes that can properly treat alkali-metal flow and heat transfer in a reduced-gravity environment. A literature search of relevant experiments in reduced gravity is reported on here, and reveals a paucity of data for such correlations. The few ongoing experiments in reduced gravity are noted. General plans are put forth for the reduced-gravity experiments which will have to be performed, at NASA facilities, with benign fluids. A similar situation exists regarding two-phase alkali-metal flow and heat transfer, even in normal gravity. Existing data are conflicting and indequate for the task of modeling a space reactor using a two-phase alkali-metal coolant. The major features of past experiments are described here. Data from the reduced-gravity experiments with innocuous fluids are to be combined with normal gravity data from the two-phase alkali-metal experiments. Analyses undertaken here give every expectation that the correlations developed from this data base will provide a valid representation of alkali-metal heat transfer and pressure drop in reduced gravity.

  11. Alkali metal carbon dioxide electrochemical system for energy storage and/or conversion of carbon dioxide to oxygen

    Science.gov (United States)

    Hagedorn, Norman H. (Inventor)

    1993-01-01

    An alkali metal, such as lithium, is the anodic reactant; carbon dioxide or a mixture of carbon dioxide and carbon monoxide is the cathodic reactant; and carbonate of the alkali metal is the electrolyte in an electrochemical cell for the storage and delivery of electrical energy. Additionally, alkali metal-carbon dioxide battery systems include a plurality of such electrochemical cells. Gold is a preferred catalyst for reducing the carbon dioxide at the cathode. The fuel cell of the invention produces electrochemical energy through the use of an anodic reactant which is extremely energetic and light, and a cathodic reactant which can be extracted from its environment and therefore exacts no transportation penalty. The invention is, therefore, especially useful in extraterrestrial environments.

  12. An Aqueous Redox Flow Battery Based on Neutral Alkali Metal Ferri/ferrocyanide and Polysulfide Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Xiaoliang; Xia, Gordon; Kirby, Brent W.; Thomsen, Edwin C.; Li, Bin; Nie, Zimin; Graff, Gordon L.; Liu, Jun; Sprenkle, Vincent L.; Wang, Wei

    2015-11-13

    Aiming to explore low-cost redox flow battery systems, a novel iron-polysulfide (Fe/S) flow battery has been demonstrated in a laboratory cell. This system employs alkali metal ferri/ferrocyanide and alkali metal polysulfides as the redox electrolytes. When proper electrodes, such as pretreated graphite felts, are used, 78% energy efficiency and 99% columbic efficiency are achieved. The remarkable advantages of this system over current state-of-the-art redox flow batteries include: 1) less corrosive and relatively environmentally benign redox solutions used; 2) excellent energy and utilization efficiencies; 3) low cost for redox electrolytes and cell components. These attributes can lead to significantly reduced capital cost and make the Fe/S flow battery system a promising low-cost energy storage technology. The major drawbacks of the present cell design are relatively low power density and possible sulfur species crossover. Further work is underway to address these concerns.

  13. Surface tension of molten alkali metal halides as a function of ion sizes

    International Nuclear Information System (INIS)

    The analysis of the experimental data on the surface tension of the liquid/vapor interphase boundary of the molten alkali metal halides MX (M Li-Cs, X = F-I) near the melting temperature, accounting for the cation and anion dimensional differences, is presented. The main attention is focused at the manifestation of the effects of the interphase boundary of the effects of the interphase boundary thickness and twofold electric layer. It is shown, that the experimental data on the whole MX series may be represented in the form of the electrocapillary curve on the graph of the surface tension dependence on the degree of the halides dimensional asymmetry

  14. X-ray Compton scattering experiments for fluid alkali metals at high temperatures and pressures

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, K., E-mail: kazuhiro-matsuda@scphys.kyoto-u.ac.jp; Fukumaru, T.; Kimura, K.; Yao, M. [Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Tamura, K. [Graduate School of Engineering, Kyoto University, Kyoto 606-8502 (Japan); Katoh, M. [A.L.M.T. Corp., Iwasekoshi-Machi 2, Toyama 931-8543 (Japan); Kajihara, Y.; Inui, M. [Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521 (Japan); Itou, M.; Sakurai, Y. [Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2015-08-17

    We have developed a high-pressure vessel and a cell for x-ray Compton scattering measurements of fluid alkali metals. Measurements have been successfully carried out for alkali metal rubidium at elevated temperatures and pressures using synchrotron radiation at SPring-8. The width of Compton profiles (CPs) of fluid rubidium becomes narrow with decreasing fluid density, which indicates that the CPs sensitively detect the effect of reduction in the valence electron density. At the request of all authors of the paper, and with the agreement of the Proceedings Editor, an updated version of this article was published on 10 September 2015. The original article supplied to AIP Publishing was not the final version and contained PDF conversion errors in Formulas (1) and (2). The errors have been corrected in the updated and re-published article.

  15. Enrichment of hydrogen isotopes while decomposition of alkali metal amalgams (Preprint No. CA-11)

    International Nuclear Information System (INIS)

    Sodium amalgam was prepared by electrolyzing caustic soda solution in a cell with flowing mercury as cathode. On decomposition of amalgam with aqueous sodium hydroxide solution in a denuder column packed with graphite pieces, the resultant hydrogen gas was depleted in deuterium. The alkali solution was enriched in deuterium content. The separation of the isotopes of some amalgam forming metals while decomposition of the amalgam of these metals with water has already been described. The separation is due to differential reaction rates of alkali metal amalgams with water containing light and heavy isotopes of hydrogen. However in the present investigation, the separation factor obtained is considerably higher than earlier reported due to possible chemical exchange between resultant hydrogen and the alkali metal hydroxide in presence of graphite surface and/or exchange of water with nascent hydrogen catalysed by OH- ions. (author). 18 refs., 3 tabs., 1 fig

  16. Neuropsychiatric manifestations of alkali metal deficiency and excess

    Energy Technology Data Exchange (ETDEWEB)

    Yung, C.Y.

    1984-01-01

    The alkali metals from the Group IA of the periodic table (lithium, sodium, potassium, rubidium, cesium and francium) are reviewed. The neuropsychiatric aspects of alkali metal deficiencies and excesses (intoxications) are described. Emphasis was placed on lithium due to its clinical uses. The signs and symptoms of these conditions are characterized by features of an organic brain syndrome with delirium and encephalopathy prevailing. There are no clinically distinctive features that could be reliably used for diagnoses. Sodium and potassium are two essential alkali metals in man. Lithium is used as therapeutic agent in bipolar affective disorders. Rubidium has been investigated for its antidepressant effect in a group of psychiatric disorders. Cesium is under laboratory investigation for its role in carcinogenesis and in depressive illness. Very little is known of francium due to its great instability for experimental study.

  17. Upgrading of petroleum oil feedstocks using alkali metals and hydrocarbons

    Science.gov (United States)

    Gordon, John Howard

    2014-09-09

    A method of upgrading an oil feedstock by removing heteroatoms and/or one or more heavy metals from the oil feedstock composition. This method reacts the oil feedstock with an alkali metal and an upgradant hydrocarbon. The alkali metal reacts with a portion of the heteroatoms and/or one or more heavy metals to form an inorganic phase separable from the organic oil feedstock material. The upgradant hydrocarbon bonds to the oil feedstock material and increases the number of carbon atoms in the product. This increase in the number of carbon atoms of the product increases the energy value of the resulting oil feedstock.

  18. Aqueous alkali metal hydroxide insoluble cellulose ether membrane

    Science.gov (United States)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1969-01-01

    A membrane that is insoluble in an aqueous alkali metal hydroxide medium is described. The membrane is a resin which is a water-soluble C2-C4 hydroxyalkyl cellulose ether polymer and an insolubilizing agent for controlled water sorption, a dialytic and electrodialytic membrane. It is particularly useful as a separator between electrodes or plates in an alkaline storage battery.

  19. Characterization of Alkali Metal Dispensers and Non-Evaporable Getter Pumps in Ultra-High Vacuum Systems for Cold Atomic Sensors

    OpenAIRE

    Scherer, David R.; Fenner, David B.; Hensley, Joel M.

    2012-01-01

    A glass ultrahigh vacuum chamber with rubidium alkali metal dispensers and non-evaporable getter pumps has been developed and used to create a cold atomic sample in a chamber that operates with only passive vacuum pumps. The ion-mass spectrum of evaporated gases from the alkali metal dispenser has been recorded as a function of dispenser current. The efficacy of the non-evaporable getter pumps in promoting and maintaining vacuum has been characterized by observation of the Rb vapor optical ab...

  20. Alkali Metal Backup Cooling for Stirling Systems - Experimental Results

    Science.gov (United States)

    Schwendeman, Carl; Tarau, Calin; Anderson, William G.; Cornell, Peggy A.

    2013-01-01

    In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor. In a previous NASA SBIR Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for Stirling RPS. The operation of these VCHPs was demonstrated using Stirling heater head simulators and GPHS simulators. In the most recent effort, a sodium VCHP with a stainless steel envelope was designed, fabricated and tested at NASA Glenn Research Center (GRC) with a Stirling convertor for two concepts; one for the Advanced Stirling Radioisotope Generator (ASRG) back up cooling system and one for the Long-lived Venus Lander thermal management system. The VCHP is designed to activate and remove heat from the stopped convertor at a 19 degC temperature increase from the nominal vapor temperature. The 19 degC temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the Multi-Layer Insulation (MLI). In addition, the same backup cooling system can be applied to the Stirling convertor used for the refrigeration system of the Long-lived Venus Lander. The VCHP will allow the refrigeration system to: 1) rest during transit at a lower temperature than nominal; 2) pre-cool the modules to an even lower temperature before the entry in Venus atmosphere; 3) work at nominal temperature on Venus surface; 4) briefly stop multiple times on the Venus surface to allow scientific measurements. This paper presents the experimental

  1. Intercalation of heavy alkali metals (K, Rb and Cs) in the bundles of single wall nanotubes

    Science.gov (United States)

    Duclaux, L.; Méténier, K.; Lauginie, P.; Salvetat, J. P.; Bonnamy, S.; Beguin, F.

    2000-11-01

    The electric-arc discharge carbon deposits (collaret) containing Single Wall Carbon Nanotubes (SWNTs) were heat treated at 1600 °C during 2 days under N2 flow in order to eliminate the Ni catalyst by sublimation, without modifications of the SWNTs ropes. Sorting this deposit by gravity enabled to obtain in the coarsest particles higher amount of SWNTs ropes than in other particle sizes. The coarser particles of the carbon deposits were reacted with the alkali metals vapor giving intercalated samples with a MC8 composition. The intercalation led to an expansion of the 2D lattice of the SWNTs so that the alkali metals were intercalated in between the tubes within the bundles. Disordered lattices were observed after intercalation of Rb and Cs. The simulations of the X-ray diffractograms of SWNTs reacted with K, gave the best fit for three K ions occupying the inter-tubes triangular cavities. The investigations by EPR, and 13C NMR, showed that doped carbon deposits are metallic.

  2. Synthesis and Structural Characterization of Alkali Metal Guanidinates

    Institute of Scientific and Technical Information of China (English)

    LUO,Yun-Jie; YAO,Ying-Ming; ZHANG,Yong; SHEN,Qi

    2007-01-01

    Reactions of 1,3-diisopropylcarbodiimide with alkali metal amides,MN(SiMe3)2(M=Li or Na)in hexane or THF produced the alkali metal guanidinates{(j-PrN)2C[N(SiMe3)2]Li}2(1)and{(i-PrN)2C[N(SiMe3)2]Na(THF)}2(2)in nearly quantitative yields.Both complexes 1 and 2 were well characterized by elemental analysis,IR spectra,1H and 13C NMR spectra,and X-ray diffraction.It was found that the guanidinates adopt different coordination modes in these complexes.

  3. Polarizabilities and hyperpolarizabilities of the alkali metal atoms

    Energy Technology Data Exchange (ETDEWEB)

    Fuentealba, P. (Chile Univ., Santiago (Chile). Departamento de Fisica and Centro de Mecanica Cuantica Aplicada (CMCA)); Reyes, O. (Chile Univ., Santiago (Chile). Dept. de Fisica)

    1993-08-14

    The electric static dipole polarizability [alpha], quadrupole polarizability C, dipole-quadrupole polarizability B, and the second dipole hyperpolarizability [gamma] have been calculated for the alkali metal atoms in the ground state. The results are based on a pseudopotential which is able to incorporate the very important core-valence correlation effect through a core polarization potential, and, in an empirical way, the main relativistic effects. The calculated properties compare very well with more elaborated calculations for the Li atom, excepting the second hyperpolarizability [gamma]. For the other atoms, there is neither theoretical nor experimental information about most of the higher polarizabilities. Hence, the results of this paper should be seen as a first attempt to give a complete account of the series expansion of the interaction energy of an alkali metal atom and a static electric field. (author).

  4. Density functional study of ferromagnetism in alkali metal thin films

    Indian Academy of Sciences (India)

    Prasenjit Sen

    2010-04-01

    Electronic and magnetic structures of (1 0 0) films of K and Cs, having thicknesses of one to seven layers, are calculated within the plane-wave projector augmented wave (PAW) formalism of the density functional theory (DFT), using both local spin density approximation (LSDA) and the PW91 generalized gradient approximation (GGA). Only a six-layer Cs film is found to have a ferromagnetic (FM) state which is degenerate with a paramagnetic (PM) state within the accuracy of these calculations. These results are compared with those obtained from calculations on a finite-thickness uniform jellium model (UJM), and it is argued that within LSDA or GGA, alkali metal thin films cannot be claimed to have an FM ground state. Relevance of these results to the experiments on transition metal-doped alkali metal thin films and bulk hosts are also discussed.

  5. Inner-shell excitation of alkali-metal atoms

    International Nuclear Information System (INIS)

    Inner-shell excitation of alkali-metal atoms, which leads to auto-ionization, is reviewed. The validity of quantum mechanical approximation is analyzed and the importance of exchange and correlation is demonstrated. Basic difficulties in making accurate calculations for inner-shell excitation process are discussed. Suggestions are made for further study of inner-shell process in atoms and ions. (author). 26 refs, 4 figs, 1 tab

  6. The unexpected properties of alkali metal iron selenide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Dagotto, Elbio R [ORNL

    2013-01-01

    The iron-based superconductors that contain FeAs layers as the fundamental building block in the crystal structures have been rationalized in the past using ideas based on the Fermi surface nesting of hole and electron pockets when in the presence of weak Hubbard U interactions. This approach seemed appropriate considering the small values of the magnetic moments in the parent compounds and the clear evidence based on photoemission experiments of the required electron and hole pockets. However, recent results in the context of alkali metal iron selenides, with generic chemical composition AxFe2ySe2 (A alkali metal element), have challenged those previous ideas since at particular compositions y the low-temperature ground states are insulating and display antiferromagnetic order with large iron magnetic moments. Moreover, angle-resolved photoemission studies have revealed the absence of hole pockets at the Fermi level in these materials. The present status of this exciting area of research, with the potential to alter conceptually our understanding of the ironbased superconductors, is here reviewed, covering both experimental and theoretical investigations. Other recent related developments are also briefly reviewed, such as the study of selenide two-leg ladders and the discovery of superconductivity in a single layer of FeSe. The conceptual issues considered established for the alkali metal iron selenides, as well as several issues that still require further work, are discussed.

  7. Alkali Metal Coolants. Proceedings of the Symposium on Alkali Metal Coolants - Corrosion Studies and System Operating Experience

    International Nuclear Information System (INIS)

    Proceedings of a Symposium organized by the IAEA and held in Vienna, 28 November - 2 December 1966. The meeting was attended by 107 participants from 16 countries and two international organizations. Contents: Review papers (2 papers); Corrosion of steels and metal alloys (6 papers); Mass transfer in alkali metal systems, behaviour of carbon (5 papers); Effects of sodium environment on mechanical properties of materials (3 papers); Effect of water leakage into sodium systems (2 papers); Design-and operation of testing apparatus (6 papers); Control, measurements and removal of impurities (13 papers); Corrosion by other alkali metals: NaK, K, Li, Cs (6 papers); Behaviour of fission products (3 papers). Each paper is in its original language (32 English, 6 French and 8 Russian) and is preceded by an abstract in English and one in the original language if this is not English. Discussions are in English. (author)

  8. Process for carbonaceous material conversion and recovery of alkali metal catalyst constituents held by ion exchange sites in conversion residue

    Science.gov (United States)

    Sharp, David W.

    1980-01-01

    In a coal gasification operation or similar conversion process carried out in the presence of an alkali metal-containing catalyst wherein solid particles containing alkali metal residues are produced, alkali metal constituents are recovered for the particles by contacting or washing them with an aqueous solution containing calcium or magnesium ions in an alkali metal recovery zone at a low temperature, preferably below about 249.degree. F. During the washing or leaching process, the calcium or magnesium ions displace alkali metal ions held by ion exchange sites in the particles thereby liberating the ions and producing an aqueous effluent containing alkali metal constituents. The aqueous effluent from the alkali metal recovery zone is then recycled to the conversion process where the alkali metal constituents serve as at least a portion of the alkali metal constituents which comprise the alkali metal-containing catalyst.

  9. Chemical compatibility of structural materials in alkali metals

    International Nuclear Information System (INIS)

    The objectives of this task are to (a) evaluate the chemical compatibility of structural alloys such as V-5 wt.%Cr-5 wt.%Ti alloy and Type 316 stainless steel for application in liquid alkali metals such as lithium and sodium-78 wt.% potassium (NaK) at temperatures in the range that are of interest for International Thermonuclear Experimental Reactor (ITER); (b) evaluate the transfer of nonmetallic elements such as oxygen, nitrogen, carbon, and hydrogen between structural materials and liquid metals; and (c) evaluate the effects of such transfers on the mechanical and microstructural characteristics of the materials for long-term service in liquid-metal-environments

  10. Integrated oil production and upgrading using molten alkali metal

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, John Howard

    2016-10-04

    A method that combines the oil retorting process (or other process needed to obtain/extract heavy oil or bitumen) with the process for upgrading these materials using sodium or other alkali metals. Specifically, the shale gas or other gases that are obtained from the retorting/extraction process may be introduced into the upgrading reactor and used to upgrade the oil feedstock. Also, the solid materials obtained from the reactor may be used as a fuel source, thereby providing the heat necessary for the retorting/extraction process. Other forms of integration are also disclosed.

  11. Alkali metal and alkali earth metal gadolinium halide scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Bourret-Courchesne, Edith; Derenzo, Stephen E.; Parms, Shameka; Porter-Chapman, Yetta D.; Wiggins, Latoria K.

    2016-08-02

    The present invention provides for a composition comprising an inorganic scintillator comprising a gadolinium halide, optionally cerium-doped, having the formula A.sub.nGdX.sub.m:Ce; wherein A is nothing, an alkali metal, such as Li or Na, or an alkali earth metal, such as Ba; X is F, Br, Cl, or I; n is an integer from 1 to 2; m is an integer from 4 to 7; and the molar percent of cerium is 0% to 100%. The gadolinium halides or alkali earth metal gadolinium halides are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

  12. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan

    International Nuclear Information System (INIS)

    The Hanford Site, located northwest of the city of Richland, Washington, houses reactors, chemical-separation systems, and related facilities used for the production of special nuclear materials, as well as for activities associated with nuclear energy development. The 300 Area of the Hanford Site contains reactor fuel manufacturing facilities and several research and development laboratories. The 3718-F Alkali Metal Treatment and Storage Facility (3718-F Facility), located in the 300 Area, was used to store and treat alkali metal wastes. Therefore, it is subject to the regulatory requirements for the storage and treatment of dangerous wastes. Closure will be conducted pursuant to the requirements of the Washington Administrative Code (WAC) 173-303-610 (Ecology 1989) and 40 CFR 270.1. Closure also will satisfy the thermal treatment facility closure requirements of 40 CFR 265.381. This closure plan presents a description of the 3718-F Facility, the history of wastes managed, and the approach that will be followed to close the facility. Only hazardous constituents derived from 3718-F Facility operations will be addressed

  13. Work function of alkali metal-adsorbed molybdenium dichalcogenides

    Science.gov (United States)

    Kim, Sol; Jhi, Seung-Hoon

    2015-03-01

    The lowest work function of materials, reported so far over the last few decades, is an order of 1eV experimentally and theoretically. Designing materials that has work-function less than 1eV is essential in the thermionic energy conversion. To explore new low work function materials, we study MoX2(X =S, Se, Te) adsorbed with alkali metals (Li, Na, K, Rb and Cs), and investigate the charge transfer, the formation of surface dipole, and the change in work function using first-principles calculations. It is found that the charge transfer from alkali metals to MoX2substrates decreases as the atomic number of adsorbates increases. Regardless of the amount of the charge transfer, K on MoTe2 exhibits the biggest surface dipole moment, which consequently makes the surface work function the lowest. We show that the formation of the surface dipole is a key in changing the work function. We find the trimerization of Mo atoms in the substrate with the lowest work-function, which may contribute to enhancement of the surface dipole.

  14. Synthesis, structure peculiarities and electric conductivity of alkali metal-rare earth silicates (germanates)

    International Nuclear Information System (INIS)

    The process of obtaining of rare earth-alkali metal silicates (germanates) is studied. The analysis of possibilities of structural disordering of alkaline cations in these structures is given. The interaction of the structure of different by the composition alkali alkali metal - rare earth silicates with electric conductivity values is shown

  15. Alkali Metal Complexes: Mixed Ligand Complexes of Some Alkali Metal Salts of Some Organic Acids with Isonitroso-PMethylace to phenone

    Directory of Open Access Journals (Sweden)

    O.P. Gupta

    2016-02-01

    Full Text Available A number of mixed ligand complexes of alkali metal salts of o-nitrophenol,2,4-dinitrophenol, 2,4,6,- trinitrophenol, 1-nitroso-2- naphthol and 8- hydroxyquinoline with Insoniroso–p methylacetopheone have been synthesized in absolute ethanol & characterized by elemental analysis and I .B. spectral data. Their I.R spectral data indicate the presence of hydrogen bonding in them, which many be one of the dominant factors of their stability. Further appreciable shift in 1650 cm-1 band (possibly vC=O and 1600 cm-1 band (possibly vC=NSuggests their coordination behavior in these mixed ligand complexes The reactions that take place in natural systems are highly specific and selective. Alkali metal ions actively participate in most of the reaction occurring in the biological systems, which are dominated by mixed ligand complexes. Studies of such mixed ligand complexes of alkali metals can threw light in understanding the role and mechanism of selective absorption of alkali metals ions by plants Coordinating ability of alkali metal with isonitrosoacetophenone1-2 and transition metals with isonitrosoacetophenone3 and isonitroso-p-methylacetophenone4 have been reported earlier. In the present paper we report the mixed ligand complexes of alkali metal salts having the general formula ML.HL, ‘ where M=Li, Na & K and L=deprotonated o- nitrophenol, 2,4 dinitrophenol, 2, 4, 6- trinitrophenol, 1-nitroso-2-naphthol or 8- hydroxquinoline; HL’= p -MeHINAP (isonitroso-p-methylacetophenone.

  16. Researches of the electrotechnical laboratory. No. 973: Study on alkali metal thermoelectric converter

    Science.gov (United States)

    Tanaka, K.; Negishi, A.; Honda, T.; Fujii, T.; Masuda, T.; Nozaki, K.

    1995-03-01

    The alkali metal thermoelectric converter (AMTEC) utilizing the sodium ion conducting Beta' '- alumina solid electrolyte (BASE) is a device to convert heat energy to electric energy directly. It is characterized by high conversion efficiencies (20 to 40 percent), high power densities (1 W/sq cm), no moving parts, low maintenance requirements, high durability, and efficiency independent of size. Because of these merits, AMTEC is one of the most promising candidate for dispersed small scale power station, remote power station and aerospace power systems. In this paper, the theoretical and experimental studies on the thin film electrodes characteristics, power generating characteristics, cell efficiency, integral electrode with large current lead, porous metal current lead, series connected cells power generation, potassium AMTEC, wick return AMTEC and system analysis for space and grand use are reported.

  17. Ion-exchange behavior of alkali metals on treated carbons

    International Nuclear Information System (INIS)

    The ion-exchange behavior of trace quantities of the alkali-metal ions sodium and cesium, on activated carbon impregnated with zirconium phosphate (referred to here as ZrP), was studied. Impregnated carbon had twice as much ion-exchange activity as unimpregnated, oxidized carbon, and 10 times as much as commercial activated carbons. The distribution coefficient of sodium increased with increasing pH; the distribution coefficient of cesium decreased with increasing pH. Sodium and cesium were separated with an electrolytic solution of 0.1 M HCl. Preliminary studies indicated that 0.2 M potassium and cesium can also be separated. Distribution coefficients of the supported ZrP were determined by the elution technique and agreed within 20% of the values for pure ZrP calculated from the literature

  18. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan

    International Nuclear Information System (INIS)

    Since 1987, Westinghouse Hanford Company has been a major contractor to the U.S. Department of Energy-Richland Operations Office and has served as co-operator of the 3718-F Alkali Metal Treatment and Storage Facility, the waste management unit addressed in this closure plan. The closure plan consists of a Part A Dangerous waste Permit Application and a RCRA Closure Plan. An explanation of the Part A Revision (Revision 1) submitted with this document is provided at the beginning of the Part A section. The closure plan consists of 9 chapters and 5 appendices. The chapters cover: introduction; facility description; process information; waste characteristics; groundwater; closure strategy and performance standards; closure activities; postclosure; and references

  19. 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)

  20. Relativistic optimized effective potential method-application to alkali metals.

    Science.gov (United States)

    Ködderitzsch, D; Ebert, H; Akai, H; Engel, E

    2009-02-11

    We present a relativistic formulation of the optimized effective potential method (ROEP) and its implementation within the Korringa-Kohn-Rostoker multiple scattering formalism. The scheme is an all-electron approach, treating core and band states formally on the same footing. We use exact exchange (EXX) as an approximation to the exchange correlation functional. Numerical four-component wavefunctions for the description of core and valence electrons and the corresponding ingredients of the ROEP integral equation are employed. The exact exchange expression for the valence states is reformulated in terms of the electronic Green's function that in turn is evaluated by making use of multiple scattering formalism. We present and discuss the application of the formalism to non-magnetic alkali metals. PMID:21715911

  1. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan

    Energy Technology Data Exchange (ETDEWEB)

    None

    1991-12-01

    Since 1987, Westinghouse Hanford Company has been a major contractor to the U.S. Department of Energy-Richland Operations Office and has served as co-operator of the 3718-F Alkali Metal Treatment and Storage Facility, the waste management unit addressed in this closure plan. The closure plan consists of a Part A Dangerous waste Permit Application and a RCRA Closure Plan. An explanation of the Part A Revision (Revision 1) submitted with this document is provided at the beginning of the Part A section. The closure plan consists of 9 chapters and 5 appendices. The chapters cover: introduction; facility description; process information; waste characteristics; groundwater; closure strategy and performance standards; closure activities; postclosure; and references.

  2. Field emission properties of capped carbon nanotubes doped by alkali metals:a theoretical investigation

    Institute of Scientific and Technical Information of China (English)

    Jin Lei; Fu Hong-Gang; Xie Ying; Yu Hai-Tao

    2012-01-01

    The electronic structures and field emission properties of capped CNT55 systems with or without alkali metal atom adsorption were systematically investigated by density functional theory calculation.The results indicate that the adsorption of alkali metal on the center site of a CNT tip is energetically favorable.In addition,the adsorption energies increase with the introduction of the electric field.The excessive negative charges on CNT tips make electron emittance much easier and result in a decrease in work function.Furthermore,the inducing effect by positively charged alkali metal atoms can be reasonably considered as the dominant reason for the improvement in field emission properties.

  3. Synthesis and properties of alkali metal intercalated fullerene-like MS2 (M=W,Mo) nanoparticles

    International Nuclear Information System (INIS)

    Layered metal disulfides - MoS2 and WS2 in the form of fullerene-like (IF) nanoparticles and in the form of platelets (crystallites of the 2H polytype) have been intercalated by exposure to alkali metal (potassium and sodium) vapor using a two-zone transport method. The composition of the intercalated systems was established using X-ray energy dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). X-ray powder diffraction (XRD) analysis and transmission electron microscopy (TEM) of the samples, which were not exposed to the ambient atmosphere, showed that they suffered little change in their lattice parameters. On the other hand, after exposure to ambient atmosphere, substantial increase in the interplanar spacing (3-5 Aa) was observed for the intercalated phases. Insertion of one to two water molecules per intercalated metal atom was suggested as a possible explanation for this large expansion along the c-axis. The modifications in magnetic and transport properties of the intercalated materials were investigated, and are believed to occur via charge transfer from the alkali metal to the conduction band of the host lattice. Restacking of the MS2 layers after prolonged exposure to the atmosphere and recovery of the pristine compound properties were observed as a result of deintercalation of the metal atoms

  4. Superconductivity of graphite intercalation compounds with alkali-metal amalgams

    International Nuclear Information System (INIS)

    Superconductivity of the alkali-metal amalgam graphite intercalation compounds of stage 1 (C4KHg, C4RbHg) and stage 2 (C8KHg, C8RbHg) has been studied as well as that of the pristine amalgams (KHg, RbHg). The transition temperatures are 0.73, 0.99, 1.90, and 1.40 K for C4KHg, C4RbHg, C8KHg, and C8RbHg, respectively. The critical-field anisotropy ratio H/sup parallel//sub c/2/H/sup perpendicular//sub c/2 is about 10 for the stage 1 and about 15 to 40 for the stage 2. It is argued that electrons in the intercalant bands rather than the graphitic bands play the main role in the superconductivity. An interesting feature is that the stage-2 compound, which has a lower density of states at the Fermi level, has a higher transition temperature than the corresponding state-1 compound

  5. Structural properties of low-density liquid alkali metals

    Indian Academy of Sciences (India)

    A Akande; G A Adebayo; O Akinlade

    2005-12-01

    The static structure factors of liquid alkali metals have been modelled at temperatures close to their melting points and a few higher temperatures using the reverse Monte Carlo (RMC) method. The positions of 5000 atoms in a box, with full periodicity, were altered until the experimental diffraction data of the structure factor agrees with the associated model structure factor within the errors. The model generated is then analysed. The position of the first peak of the pair distribution function () does not show any significant temperature dependence and the mean bond lengths can be approximated within an interval of 3.6–5.3 Å, 4.5–6.6 Å, 4.8–6.7 Å and 5.1–7.3 Å for Na, K, Rb and Cs respectively. The cosine bond distributions show similar trend with the flattening up of the first peak with increase in temperature. In addition, the coordination numbers of these liquid metals are high due to the presence of non-covalent bonding between them. On the average, we surmise that the coordination number decreases with increase in temperature.

  6. Electrochemistry of ytterbium (III) in molten alkali metal chlorides

    Energy Technology Data Exchange (ETDEWEB)

    Smolenski, V.; Novoselova, A. [Institute of High-Temperature Electrochemistry, Ural Division, Russian Academy of Science, Ekaterinburg, 620219 (Russian Federation); Osipenko, A. [Research Institute of Atomic Reactors, Dimitrovgrad-10, Ulyanovsk Region, 433010 (Russian Federation); Caravaca, C. [High Level Waste Unit, Nuclear Fission Division, CIEMAT, Madrid, 28040 (Spain); Cordoba, G. de [High Level Waste Unit, Nuclear Fission Division, CIEMAT, Madrid, 28040 (Spain)], E-mail: g.cordoba@ciemat.es

    2008-12-30

    This work presents the electrochemical study of Yb(III) ions in molten alkali metal chlorides in the temperature range 723-1073 K. Transient electrochemical techniques such as linear sweep, cyclic and square wave voltammetry, and potentiometry at zero current have been used to investigate the reduction mechanism, transport parameters and thermodynamic properties of the reaction YbCl{sub 2} + 1/2Cl{sub 2} = YbCl{sub 3} The results obtained show that the reduction reaction Yb(III) + e{sup -} {r_reversible} Yb(II) is reversible being controlled by the rate of the mass transfer. The diffusion coefficient of [YbCl{sub 6}]{sup 3-} complex ions has been determined at different temperatures in the fused eutectic LiCl-KCl, the equimolar NaCl-KCl and the CsCl media. The apparent standard potential of the soluble-soluble redox system Yb(III)/Yb(II) has been obtained by cyclic voltammetry. The influence of the nature of the solvent on the electrochemical and thermodynamic properties of ytterbium compounds is discussed.

  7. Corrosion in alkali metal/molybdenum heat pipes

    International Nuclear Information System (INIS)

    Molybdenum/sodium (Mo/Na) and molybdenum/lithium (Mo/Li) heat pipes have been operated for long periods of time in a study of their resistance to failure by alkali metal corrosion. Some Mo/Na heat pipes have operated over 20,600 h at 1400 K without failure, while at least one similar heat pipe failed in less than 14 hours at 1435 K. Detailed post-mortem analyses which have been performed on three failed Mo/Na heat pipes all indicated impurity controlled corrosion of their evaporators. Impurities observed to be transported included carbon, oxygen, and silicon. A Mo/Li heat pipe that failed after 25,216 h of operation at 1700 K was also examined in detail. This failure was due to nickel impurities being transported to the evaporator resulting in perforation of the container tube by the formation of a low melting Mo-Ni alloy. Theoretical thermochemical calculations were conducted for these systems with the objective of corroborating the corrosion mechanisms in both types of heat pipes. The results of these calculations are in general agreement with the observed corrosion a phenomena

  8. Second virial coefficients and viscosity property of monatomic alkali-metal gases

    International Nuclear Information System (INIS)

    In this work, we have calculated the second virial coefficients B2 of monatomic lithium, sodium, and potassium gases by using the most recent 1Σg+ and 3Σu+ Rydberg-Klein-Rees interatomic potentials. We have also determined the viscosity η and thermal conductivity λ coefficients of the alkali-metal vapors as a function of the temperature T. The results we have found of the collision integrals and of the coefficients η and λ agree quite well with some available experimental data. Besides, we have investigated the variation law with temperature T of the above thermophysical quantities. For temperatures ranging from 100 K to 3,000 K, the results can be reproduced by simple formulas η(T)=ATα and λ(T)=BTα, where for T in Kelvin, η in micropoise, and λ in 10-3 W·m-1·K-1, for lithium Li:A=0.314, B=0.1398, and α=0.863; for sodium Na:A=0.624, B=0.0846, and α=0.827; for potassium K:A=0.400, B=0.0320, and α=0.883. (author)

  9. Modification of alkali metals on silicon-based nanoclusters: An enhanced nonlinear optical response

    Science.gov (United States)

    Li, Xiaojun; Han, Quan; Yang, Xiaohui; Song, Ruijuan; Song, Limei

    2016-08-01

    Structures, chemical stabilities and nonlinear optical properties of alkali metals-adsorbed niobium-doped silicon (M@SinNb+) clusters are investigated using the DFT methods. The alkali metals prefer energetically to be attached as bridged bond rather than M-Si single bond in most of optimized structures. Adsorption of alkali metals on doped silicon clusters gradually enhances their chemical stabilities with increasing cluster size. Noteworthily, the first hyperpolarizabilities (βtot) of the M@SinNb+ clusters, obtained by using the long-range corrected CAM-B3LYP functional, are large enough to establish their strong nonlinear optical behavior, especially for M@Si9Nb+ (M = Li, Na, and K), and the enhanced βtot ordering by alkali metals is Na > K > Li.

  10. Method and composition for testing for the presence of an alkali metal

    International Nuclear Information System (INIS)

    A method and composition for detecting the presence of an alkali metal on the surface of a body such as a metal plate, tank, pipe or the like is provided. The method comprises contacting the surface with a thin film of a liquid composition comprising a light-colored pigment, an acid-base indicator, and a nonionic wetting agent dispersed in a liquid carrier comprising a minor amount of water and a major amount of an organic solvent selected from the group consisting of the lower aliphatic alcohols, ketones and ethers. Any alkali metal present on the surface in elemental form or as an alkali metal hydroxide or alkali metal carbonate will react with the acid-base indicator to produce a contrasting color change in the thin film, which is readily discernible by visual observation or automatic techniques

  11. Measuring the spin polarization of alkali-metal atoms using nuclear magnetic resonance frequency shifts of noble gases

    International Nuclear Information System (INIS)

    We report a novel method of measuring the spin polarization of alkali-metal atoms by detecting the NMR frequency shifts of noble gases. We calculated the profile of 87Rb D1 line absorption cross sections. We then measured the absorption profile of the sample cell, from which we calculated the 87Rb number densities at different temperatures. Then we measured the frequency shifts resulted from the spin polarization of the 87Rb atoms and calculated its polarization degrees at different temperatures. The behavior of frequency shifts versus temperature in experiment was consistent with theoretical calculation, which may be used as compensative signal for the NMRG closed-loop control system

  12. Properties of Hydrated Alkali Metals Aimed at the Ion Channel Selectivity

    Institute of Scientific and Technical Information of China (English)

    AN Hai-Long; LIU Yu-Zhi; ZHANG Su-Hua; ZHAN Yong; ZHANG Hai-Lin

    2008-01-01

    The hydration structure properties of different alkali metal ions with eight water molecules and potassium ions with different numbers of water molecules are studied using the mixed density functional theory, B3LYP, with 6-311G basis set. The hydration structures are obtained from structure optimization and the optimum numbers of water molecules in the innermost hydration shell for the alkali metal ions are found. Some useful information about the ion channel selectivity is presented.

  13. The effect of the alkali metal cation on the electrocatalytic oxidation of formate on platinum

    OpenAIRE

    Previdello, B.; E. Machado; Varela, H.

    2014-01-01

    Non-covalent interactions between hydrated alkali metal cations and adsorbed oxygenated species on platinum might considerably inhibit some electrocatalytic reactions. We report in this communication the effect exerted by electrolyte alkali metal cations on the electro-oxidation of formate ions on platinum. The system was investigated by means of cyclic voltammetry and chronoamperometry in the presence of an electrolyte containing Li+, Na+, or K+. As already observed for other systems, the ge...

  14. A contribution to the surface characterization of alkali metal sulfates

    Energy Technology Data Exchange (ETDEWEB)

    Fantauzzi, Marzia; Rigoldi, Americo; Elsener, Bernhard; Atzei, Davide; Rossi, Antonella, E-mail: rossi@unica.it

    2014-03-01

    Highlights: • Full electronic characterization of alkali metals sulfates by X-ray photoelectron spectroscopy and X-ray induced Auger electron spectroscopy. • Curve-fitting of SKLL signals makes possible to clarify the role of the cation in the series of alkali metal sulfates. • Differences in the binding energies and Auger parameter are discussed in terms of the electronic properties and the polarizability of the cation. • The line intensities are analyzed and a thorough quantitative analysis is presented. - Abstract: The analytical characterization of surfaces of sulfur-bearing samples that present sulfides, polysulfides and/or elemental sulfur as reaction products can be difficult by simply relying on the binding energy of the S2p X-ray photoelectron signals, due to the small chemical shifts. In such cases the Auger parameter concept can be used to distinguish among different chemical states, but this requires a model to curve fit complex Auger SKLL signals in order to resolve the contributions arising from sulfur in different chemical states on the surface. With this scope a detailed X-ray photoelectron spectroscopy (XPS) and X-ray induced Auger electron spectroscopy (XAES) surface analytical study of the group IA sulfates is presented in this paper. Sulfates were chosen as model compounds for curve fitting the X-ray induced SKLL spectra since in these compounds sulfur is present in a unique chemical state. For the first time the multicomponent SKLL spectra are fitted with model functions consisting of an intense {sup 1}D and a low intensity {sup 1}S contribution with constant energy difference of 8 eV. It was found that the kinetic energy of the SK{sub 2,3}L{sub 2,3} ({sup 1}D) line increases from 2105.1 ± 0.1 to 2107.5 ± 0.2 eV whereas the corresponding S2p{sub 3/2} binding energy decreases from 169.5 ± 0.1 eV for Li{sub 2}SO{sub 4} to 167.8 ± 0.1 eV for Cs{sub 2}SO{sub 4}. Shifts to lower binding energy values are observed also for S2p, S2s and O1

  15. On the origin of alkali metals in Europa exosphere

    Science.gov (United States)

    Ozgurel, Ozge; Pauzat, Françoise; Ellinger, Yves; Markovits, Alexis; Mousis, Olivier; LCT, LAM

    2016-10-01

    At a time when Europa is considered as a plausible habitat for the development of an early form of life, of particular concern is the origin of neutral sodium and potassium atoms already detected in its exosphere (together with magnesium though in smaller abundance), since these atoms are known to be crucial for building the necessary bricks of prebiotic species. However their origin and history are still poorly understood. The most likely sources could be exogenous and result from the contamination produced by Io's intense volcanism and/or by meteoritic bombardment. These sources could also be endogenous if these volatile elements originate directly from Europa's icy mantle. Here we explore the possibility that neutral sodium and potassium atoms were delivered to the satellite's surface via the upwelling of ices formed in contact with the hidden ocean. These metallic elements would have been transferred as ions to the ocean at early epochs after Europa's formation, by direct contact of water with the rocky core. During Europa's subsequent cooling, the icy layers formed at the top of the ocean would have kept trapped the sodium and potassium, allowing their future progression to the surface and final identification in the exosphere of the satellite. To support this scenario, we have used chemistry numerical models based on first principle periodic density functional theory (DFT). These models are shown to be well adapted to the description of compact ice and are capable to describe the trapping and neutralization of the initial ions in the ice matrix. The process is found relevant for all the elements considered, alkali metals like Na and K, as well as for Mg and probably for Ca, their respective abundances depending essentially of their solubility and chemical capabilities to blend with water ices.

  16. Rubidium "whiskers" in a vapor cell

    CERN Document Server

    Balabas, M V; Sushkov, A O

    2006-01-01

    Crystals of metallic rubidium are observed ``growing'' from paraffin coating of buffer-gas-free glass vapor cells. The crystals have uniform square cross-section, $\\approx 35 \\mu$m on the side, and reach several mm in length.

  17. Alkali metal and simple gas atom adsorption and coadsorption on transition metal surfaces

    CERN Document Server

    Norris, A G

    2000-01-01

    system is formed by adsorption of potassium or cesium on the Ni(100)c(2x2)-O overlayer. The difficulty of the structural fit is compounded' by the size of the unit cell. In this study, Anomalous Scattering was used to investigate whether there is a contribution from the nickel substrate to the reconstruction. Measurements of the fractional order rods at 10 eV and 200 eV below the nickel K edge (8333 eV) showed no discernible differences and involvement of the nickel substrate in the reconstruction can be eliminated. Alkali metal coadsorption systems represent a step along the pathway from simple model adsorbate overlayers to more technologically relevant real systems. Such is their complexity, however, that very few systems have been solved structurally. Presented here are SXRD and STM investigations of two such systems. The first study involves potassium adsorption on the Ni(100)(2x2)p4g-N surface, where a clock reconstruction is present with the nickel substrate atoms rotated in alternate clockwise and anti...

  18. Hyperfine-frequency shifts of alkali-metal atoms during long-range collisions

    CERN Document Server

    McGuyer, B H

    2013-01-01

    Collisions with chemically inert atoms or molecules change the hyperfine coupling of an alkali-metal atom through the hyperfine-shift interaction. This interaction is responsible for the pressure shifts of the microwave resonances of alkali-metal atoms in buffer gases, is an important spin interaction in alkali-metal--noble-gas van der Waals molecules, and is anticipated to enable the magnetoassociation of ultracold molecules such as RbSr. An improved estimate is presented for the long-range asymptote of this interaction for Na, K, Rb, and Cs. To test the results, the change in hyperfine coupling due to a static electric field is estimated and reasonable agreement is found.

  19. Hydration number of alkali metal ions determined by insertion in a conducting polymer

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2008-01-01

    In aqueous solutions, the alkali metals ions are associated with a number of H2O molecules. A distinction is made between a primary solvent shell, (or inner solvation shell), consisting of H2O molecules directly coordinated to the metal ion, and a secondary (or outer) solvation shell, consisting....... The solvation of alkali metal ions has been discussed for many years without a clear consensus. This work presents a systematic study of the hydration numbers of the 5 alkali metal ions, using the electrochemical insertion of the ions in a conducting polymer (polypyrrole containing the large immobile anion DBS......-). The technique of Electrochemical Quartz Crystal Microbalance (EQCM) has been used to simultaneously determine the mass entering a film of PPy(DBS), and the charge during the first reduction. The method determines the total mass of metal ions and H2O entering the film quite accurately. The charge inserted allows...

  20. Determination of membrane hydration numbers of alkali metal ions by insertion in a conducting polymer

    DEFF Research Database (Denmark)

    Skaarup, Steen; Junaid Mohamed Jafeen, Mohamed; Careem, M.A.

    2010-01-01

    In aqueous solutions, the alkali metals ions, Li+, Na+, K+, Rb+ and Cs+ are known to be associated with a number of H2O molecules. Traditionally, a distinction is made between a primary solvent shell, (or inner solvation shell), consisting of H2O molecules directly coordinated to the metal ion...... may depend on the details of ion hydration. Although the solvation of alkali metal ions in aqueous solution has been discussed for many years, there is still no clear consensus. Part of the discrepancy is simply that different methods measure over different time scales, and therefore do...... not necessarily define the same hydration shell. This work presents a systematic study of one special variant of the hydration numbers of the 5 alkali metal ions, using the electrochemical insertion of the ions in a conducting polymer (polypyrrole containing the large immobile anion DBS-). The technique...

  1. Ionic conduction in alkali metal doped ZnFe/sub 2/O/sub 4/ compound

    International Nuclear Information System (INIS)

    Zinc ferric oxide (ZnFe/sub 2/O/sub 4/) has been synthesized by liquid phase chemical reaction from aqueous mixture of zinc chloride and ferric chloride in sodium hydroxide (4N) solution and effect of alkali metal on electrical characteristics was explored. The well characterized powder was pressed into pellets and dried at 80 degree C. Samples with alkali metal concentrations 10-100 ppm have been investigated to I-V measurements. The conductivity of pure compound (10-/sub 2/omega-cm)/sup-1/) lies in the semiconductor range but due to alkali metal doping the compound shows ionic conduction at room temperature. The ionic conduction is found to be increased as the dopant concentration increases.(author)

  2. A hetero-alkali-metal version of the utility amide LDA: lithium-potassium diisopropylamide.

    Science.gov (United States)

    Armstrong, David R; Kennedy, Alan R; Mulvey, Robert E; Robertson, Stuart D

    2013-03-14

    Designed to extend the synthetically important alkali-metal diisopropylamide [N(i)Pr(2); DA] class of compounds, the first example of a hetero-alkali-metallic complex of DA has been prepared as a partial TMEDA solvate. Revealed by an X-ray crystallographic study, its structure exists as a discrete lithium-rich trinuclear Li(2)KN(3) heterocycle, with TMEDA only solvating the largest of the alkali-metals, with the two-coordinate lithium atoms being close to linearity [161.9(2)°]. A variety of NMR spectroscopic studies, including variable temperature and DOSY NMR experiments, suggests that this new form of LDA maintains its integrity in non-polar hydrocarbon solution. This complex thus represents a rare example of a KDA molecule which is soluble in non-polar medium without the need for excessive amounts of solubilizing Lewis donor being added.

  3. Thermochemistry of complex oxides of uranium(6), arsenic and alkali metals

    International Nuclear Information System (INIS)

    Standard reaction enthalpies for stoichiometric mixtures of mono-potassium orthoarsenate, uranium(6) and alkali metal nitrate oxides as well as mixtures of complex oxides of the M1AsUO6 (M1 = Li, Na, K, Rb, Cs) general formulas and potassium nitrate with hydrofluoric acid are determined in adiabatic calorimeter at the temperature of 298.15 K. Standard enthalpies for formation of complex oxides of uranium(6), arsenic and alkali metals at the temperature of 298.15 K are calculated by the obtained results. 8 refs., 1 tab

  4. Method for preparation of melts of alkali metal chlorides with highly volatile polyvalent metal chlorides

    International Nuclear Information System (INIS)

    A method for production of alkali metal (Cs, Rb, K) chloride melts with highly volatile polyvalent metal chlorides is suggested. The method consists, in saturation of alkali metal chlorides, preheated to the melting point, by volatile component vapours (titanium tetrachloride, molybdenum or tantalum pentachloride) in proportion, corresponding to the composition reguired. The saturation is realized in an evacuated vessel with two heating areas for 1-1.5 h. After gradual levelling of temperature in both areas the product is rapidly cooled. 1 fig.; 1 tab

  5. Antiproton and proton collisions with the alkali-metal atoms Li, Na, and K

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Saenz, Alejandro

    2008-01-01

    Single-electron ionization and excitation cross sections as well as cross sections for excitation into the first excited p state of the alkali-metal atoms Li(2s), Na(3s), and K(4s) colliding with antiprotons and protons were calculated using a time-dependent channel-coupling approach. For antipro......Single-electron ionization and excitation cross sections as well as cross sections for excitation into the first excited p state of the alkali-metal atoms Li(2s), Na(3s), and K(4s) colliding with antiprotons and protons were calculated using a time-dependent channel-coupling approach...

  6. Oxidative coal desulfurization using lime to regenerate alkali metal hydroxide from reaction product

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, S.

    1980-07-22

    A process for the removal of pyrite from coal comprises (A) preparing an aqueous slurry containing finely divided coal particles; (B) adding to the slurry an alkali metal hydroxide selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide, as well as mixtures thereof, in amounts sufficient to continuously maintain the pH of the slurry at a value of below about 8; (C) agitating the slurry while treating the slurry with oxygen or an oxygen-containing gas at substantially atmospheric pressuresand at a slightly elevated temperature of at least about 70/sup 0/C to convert the pyrite in the coal to a soluble alkali metal sulfate; (D) reacting lime with the so-formed alkali metal sulfate to regenerate the alkali metal hydroxide; and (E) recycling the hydroxide for further use in the process, whereby pyrite is effectively removed and the hydroxide conveniently regenerated with the inhibiting effect of calcium ions therein upon the oxygen leaching of said pyritic sulfur from coal being overcome at said pH, the reaction rate being enhanced by the use of said elevated temperature.

  7. Phonon dispersion in alkali metals and their equiatomic sodium-based binary alloys

    Institute of Scientific and Technical Information of China (English)

    Aditya M. VORA

    2008-01-01

    In the present article, the theoretical calcula-tions of the phonon dispersion curves (PDCs) of five alkali metals viz. Li, Na, K, Rb, Cs and their four equia-tomic sodium-based binary alloys viz. Na0.5Li0.5,Na0.5K0.5, Na0.5Rb0.5 and Na0.5Cs0.5 to second order in a local model potential is discussed in terms of the real-space sum of the Born yon Karman central force con-stants. Instead of the concentration average of the force constants of pure alkali metals, the pseudo-alloy-atom (PAA) is adopted to directly compute the force constants of the four equiatomic sodium based binary alloys and was successfully applied. The exchange and correlation functions due to the Hartree (H) and Ichimaru-Utsumi (IU) are used to investigate the influence of the screening effects. The phonon frequencies of alkali metals and their four equiatomic sodium-based binary alloys in the longit-udinal branch are more sensitive to the exchange and cor-relation effects in comparison with the transverse branches. The PDCs of pure alkali metals are found in qualitative agreement with the available experimental data. The frequencies in the longitudinal branch are sup-pressed rather due to IU-screening function than those due to static H-screening function.

  8. Oxygen production by molten alkali metal salts using multiple absorption-desorption cycles

    Science.gov (United States)

    Cassano, Anthony A.

    1985-01-01

    A continuous chemical air separation is performed wherein oxygen is recovered with a molten alkali metal salt oxygen acceptor in a series of absorption zones which are connected to a plurality of desorption zones operated in separate parallel cycles with the absorption zones. A greater recovery of high pressure oxygen is achieved at reduced power requirements and capital costs.

  9. Alkali metal ion binding to glutamine and glutamine derivatives investigated by infrared action spectroscopy and theory

    NARCIS (Netherlands)

    Bush, M. F.; Oomens, J.; Saykally, R. J.; Williams, E. R.

    2008-01-01

    The gas-phase structures of alkali-metal cationized glutamine are investigated by using both infrared multiple photon dissociation (TRMPD) action spectroscopy, utilizing light generated by a free electron laser, and theory. The IRMPD spectra contain many similarities that are most consistent with gl

  10. Long-range interactions between excited helium and alkali-metal atoms

    KAUST Repository

    Zhang, J.-Y.

    2012-12-03

    The dispersion coefficients for the long-range interaction of the first four excited states of He, i.e., He(2 1,3S) and He(2 1,3P), with the low-lying states of the alkali-metal atoms Li, Na, K, and Rb are calculated by summing over the reduced matrix elements of the multipole transition operators. For the interaction between He and Li the uncertainty of the calculations is 0.1–0.5%. For interactions with other alkali-metal atoms the uncertainty is 1–3% in the coefficient C5, 1–5% in the coefficient C6, and 1–10% in the coefficients C8 and C10. The dispersion coefficients Cn for the interaction of He(2 1,3S) and He(2 1,3P) with the ground-state alkali-metal atoms and for the interaction of He(2 1,3S) with the alkali-metal atoms in their first 2P states are presented in this Brief Report. The coefficients for other pairs of atomic states are listed in the Supplemental Material.

  11. Modified PVA-CA blend ultrafiltration membrane by alkali metal chloride

    Institute of Scientific and Technical Information of China (English)

    张启修; 邱运仁

    2003-01-01

    The modified PVA-CA blend ultrafiltration membranes were prepared by phase inversion from the casting solutions consisting of polyvinyl alcohol(PVA), cellulose acetate(CA), acetic acid, alkali metal chloride and water. The effects of different concentration of alkali metal chloride on the properties of membranes were investigated. The results show that when the mass fraction of the salt in the casting solution is not greater than 1%, the property of rejection of the alkali metal salt modified ultrafiltration PVA-CA blend membrane has little change compared with that of the unmodified PVA-CA blend membrane, but the permeation flux is much greater than that of the unmodified membrane under the same operation condition. When the mass fraction of the salt is greater than 1.5%, the permeate flux increases much greater than that of the unmodified membrane, but the property of rejection of the modified ultrafiltration membrane decreases greatly. The results also show that the contact angle of the salt modified PVA-CA blend UF membrane decreases but the swelling in water increases with the increment of the mass fraction of alkali metal salts. Furthermore, the NaCl modified PVA-CA blend membrane has a slightly lower swelling and a little smaller contact angle of water than the KCl modified PVA-CA blend membrane does when the mass fraction of salts is the same.

  12. Unidirectional thermal expansion in KZnB3O6: role of alkali metals.

    Science.gov (United States)

    Lou, Yanfang; Li, Dandan; Li, Zhilin; Zhang, Han; Jin, Shifeng; Chen, Xiaolong

    2015-12-14

    The driving force of the unidirectional thermal expansion in KZnB3O6 has been studied experimentally and theoretically. Our results show that the low-energy vibrational modes of alkali metals play a crucial role in this unusual thermal behavior. PMID:26515521

  13. Croconic acid and alkali metal croconate salts: some new insights into an old story.

    Science.gov (United States)

    Braga, Dario; Maini, Lucia; Grepioni, Fabrizia

    2002-04-15

    The solid-state structures of a series of alkali metal salts of the croconate dianion (C(5)O(5)(2-)) and of croconic acid (H(2)C(5)O(5)) have been determined. The alkali metal croconates were obtained by ring contraction of rhodizonic acid (H(2)C(6)O(6)), upon treatment with alkali metal hydroxides and recrystallisation from water. The novel species Na(2)C(5)O(5) x 2H(2)O, Rb(2)C(5)O(5) and Cs(2)C(5)O(5), as well as the mixed hydrogencroconate/croconate salt K(3)(HC(5)O(5))(C(5)O(5)) small middle dot2 H(2)O are described and compared with the Li(+), K(+) and NH(4)(+) salts. Single crystals of croconic acid were obtained by crystallisation of croconic acid in the presence of HCl. Crystal structure determinations showed that the C(5)O(5)(2-) ions tend to organize themselves in columns. The interplanar separations lie in the narrow range 3.12-3.42 A and do not necessarily reflect the presence of pi-stacking interactions. It is argued that the small interplanar separation is the result of a compromise between packing of flat croconate units and the spherical cations together with the water molecules that fill the coordination spheres of the alkali metal atoms. PMID:11933108

  14. Alkali Metal Halide Salts as Interface Additives to Fabricate Hysteresis-Free Hybrid Perovskite-Based Photovoltaic Devices.

    Science.gov (United States)

    Wang, Lili; Moghe, Dhanashree; Hafezian, Soroush; Chen, Pei; Young, Margaret; Elinski, Mark; Martinu, Ludvik; Kéna-Cohen, Stéphane; Lunt, Richard R

    2016-09-01

    A new method was developed for doping and fabricating hysteresis-free hybrid perovskite-based photovoltaic devices by using alkali metal halide salts as interface layer additives. Such salt layers introduced at the perovskite interface can provide excessive halide ions to fill vacancies formed during the deposition and annealing process. A range of solution-processed halide salts were investigated. The highest performance of methylammonium lead mixed-halide perovskite device was achieved with a NaI interlayer and showed a power conversion efficiency of 12.6% and a hysteresis of less than 2%. This represents a 90% improvement compared to control devices without this salt layer. Through depth-resolved mass spectrometry, optical modeling, and photoluminescence spectroscopy, this enhancement is attributed to the reduction of iodide vacancies, passivation of grain boundaries, and improved hole extraction. Our approach ultimately provides an alternative and facile route to high-performance and hysteresis-free perovskite solar cells.

  15. Measuring the spin polarization of alkali-metal atoms using nuclear magnetic resonance frequency shifts of noble gases

    Directory of Open Access Journals (Sweden)

    X. H. Liu

    2015-10-01

    Full Text Available We report a novel method of measuring the spin polarization of alkali-metal atoms by detecting the NMR frequency shifts of noble gases. We calculated the profile of 87Rb D1 line absorption cross sections. We then measured the absorption profile of the sample cell, from which we calculated the 87Rb number densities at different temperatures. Then we measured the frequency shifts resulted from the spin polarization of the 87Rb atoms and calculated its polarization degrees at different temperatures. The behavior of frequency shifts versus temperature in experiment was consistent with theoretical calculation, which may be used as compensative signal for the NMRG closed-loop control system.

  16. Measuring the spin polarization of alkali-metal atoms using nuclear magnetic resonance frequency shifts of noble gases

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X. H.; Luo, H.; Qu, T. L., E-mail: qutianliang@nudt.edu.cn; Yang, K. Y.; Ding, Z. C. [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2015-10-15

    We report a novel method of measuring the spin polarization of alkali-metal atoms by detecting the NMR frequency shifts of noble gases. We calculated the profile of {sup 87}Rb D1 line absorption cross sections. We then measured the absorption profile of the sample cell, from which we calculated the {sup 87}Rb number densities at different temperatures. Then we measured the frequency shifts resulted from the spin polarization of the {sup 87}Rb atoms and calculated its polarization degrees at different temperatures. The behavior of frequency shifts versus temperature in experiment was consistent with theoretical calculation, which may be used as compensative signal for the NMRG closed-loop control system.

  17. Elucidation of transport mechanism and enhanced alkali ion transference numbers in mixed alkali metal-organic ionic molten salts.

    Science.gov (United States)

    Chen, Fangfang; Forsyth, Maria

    2016-07-28

    Mixed salts of Ionic Liquids (ILs) and alkali metal salts, developed as electrolytes for lithium and sodium batteries, have shown a remarkable ability to facilitate high rate capability for lithium and sodium electrochemical cycling. It has been suggested that this may be due to a high alkali metal ion transference number at concentrations approaching 50 mol% Li(+) or Na(+), relative to lower concentrations. Computational investigations for two IL systems illustrate the formation of extended alkali-anion aggregates as the alkali metal ion concentration increases. This tends to favor the diffusion of alkali metal ions compared with other ionic species in electrolyte solutions; behavior that has recently been reported for Li(+) in a phosphonium ionic liquid, thus an increasing alkali transference number. The mechanism of alkali metal ion diffusion via this extended coordination environment present at high concentrations is explained and compared to the dynamics at lower concentrations. Heterogeneous alkali metal ion dynamics are also evident and, somewhat counter-intuitively, it appears that the faster ions are those that are generally found clustered with the anions. Furthermore these fast alkali metal ions appear to correlate with fastest ionic liquid solvent ions. PMID:27375042

  18. Vanadium oxide based cpd. useful as a cathode active material - is used in lithium or alkali metal batteries to prolong life cycles

    DEFF Research Database (Denmark)

    1997-01-01

    A mixt. of metallic iron particles and vanadium pentoxide contg. V in its pentavalent state in a liq. is reacted to convert at least some of the pentavalent V to its tetravalent state and form a gel. The liq. phase is then sepd. from the oxide based gel to obtain a solid material(I) comprising Fe......, V and oxygen where at least some of the V is in the tetravalent state. USE-(I) is a cathode active material in electric current producing storage cells. ADVANTAGE-Use of (I) in Li or alkali metal batteries gives prolonged life cycles.Storage cells using (I) have improved capacity during charge and...

  19. Reactions between cold methyl halide molecules and alkali-metal atoms

    CERN Document Server

    Lutz, Jesse J

    2013-01-01

    We investigate the potential energy surfaces and activation energies for reactions between methyl halide molecules CH$_{3}X$ ($X$ = F, Cl, Br, I) and alkali-metal atoms $A$ ($A$ = Li, Na, K, Rb) using high-level {\\it ab initio} calculations. We examine the anisotropy of each intermolecular potential energy surface (PES) and the mechanism and energetics of the only available exothermic reaction pathway, ${\\rm CH}_{3}X+A\\rightarrow{\\rm CH}_{3}+AX$. The region of the transition state is explored using two-dimensional PES cuts and estimates of the activation energies are inferred. Nearly all combinations of methyl halide and alkali-metal atom have positive barrier heights, indicating that reactions at low temperatures will be slow.

  20. Reactions between cold methyl halide molecules and alkali-metal atoms

    International Nuclear Information System (INIS)

    We investigate the potential energy surfaces and activation energies for reactions between methyl halide molecules CH3X (X = F, Cl, Br, I) and alkali-metal atoms A (A = Li, Na, K, Rb) using high-level ab initio calculations. We examine the anisotropy of each intermolecular potential energy surface (PES) and the mechanism and energetics of the only available exothermic reaction pathway, CH3X + A → CH3 + AX. The region of the transition state is explored using two-dimensional PES cuts and estimates of the activation energies are inferred. Nearly all combinations of methyl halide and alkali-metal atom have positive barrier heights, indicating that reactions at low temperatures will be slow

  1. Alkali Metal Carbenoids: A Case of Higher Stability of the Heavier Congeners.

    Science.gov (United States)

    Molitor, Sebastian; Gessner, Viktoria H

    2016-06-27

    As a result of the increased polarity of the metal-carbon bond when going down the group of the periodic table, the heavier alkali metal organyl compounds are generally more reactive and less stable than their lithium congeners. We now report a reverse trend for alkali metal carbenoids. Simple substitution of lithium by the heavier metals (Na, K) results in a significant stabilization of these usually highly reactive compounds. This allows their isolation and handling at room temperature and the first structure elucidation of sodium and potassium carbenoids. The control of stability was used to control reactivity and selectivity. Hence, the Na and K carbenoids act as selective carbene-transfer reagents, whereas the more labile lithium systems give rise to product mixtures. Additional fine tuning of the M-C interaction by means of crown ether addition further allows for control of the stability and reactivity. PMID:27100278

  2. Equation of state for thermodynamic properties of pure and mixtures liquid alkali metals

    Energy Technology Data Exchange (ETDEWEB)

    Mousazadeh, M.H., E-mail: mmousazadeh@aeoi.org.ir [Department of Chemistry, Nuclear Science Research School, Nuclear Science and Technology Research Institute (NSTRI), End of North-Karegar Str., 11365-3486 Tehran (Iran, Islamic Republic of); Faramarzi, E. [Department of Physical Chemistry, School of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Maleki, Z. [Department of Chemistry, Nuclear Science Research School, Nuclear Science and Technology Research Institute (NSTRI), End of North-Karegar Str., 11365-3486 Tehran (Iran, Islamic Republic of)

    2010-11-20

    We developed an equation of state based on statistical-mechanical perturbation theory for pure and mixtures alkali metals. Thermodynamic properties were calculated by the equation of state, based on the perturbed-chain statistical associating fluid theory (PC-SAFT). The model uses two parameters for a monatomic system, segment size, {sigma}, and segment energy, {epsilon}. In this work, we calculate the saturation and compressed liquid density, heat capacity at constant pressure and constant volume, isobaric expansion coefficient, for which accurate experimental data exist in the literatures. Results on the density of binary and ternary alkali metal alloys of Cs-K, Na-K, Na-K-Cs, at temperatures from the freezing point up to several hundred degrees above the boiling point are presented. The calculated results are in good agreement with experimental data.

  3. The 3-Dimensional q-Deformed Harmonic Oscillator and Magic Numbers of Alkali Metal Clusters

    CERN Document Server

    Bonatsos, Dennis; Raychev, P P; Roussev, R P; Terziev, P A; Bonatsos, Dennis

    1999-01-01

    Magic numbers predicted by a 3-dimensional q-deformed harmonic oscillator with Uq(3) > SOq(3) symmetry are compared to experimental data for alkali metal clusters, as well as to theoretical predictions of jellium models, Woods--Saxon and wine bottle potentials, and to the classification scheme using the 3n+l pseudo quantum number. The 3-dimensional q-deformed harmonic oscillator correctly predicts all experimentally observed magic numbers up to 1500 (which is the expected limit of validity for theories based on the filling of electronic shells), thus indicating that Uq(3), which is a nonlinear extension of the U(3) symmetry of the spherical (3-dimensional isotropic) harmonic oscillator, is a good candidate for being the symmetry of systems of alkali metal clusters.

  4. Conductometric determination of dissociation constants of alkali metal monopyrocatechinborates in alcohols

    International Nuclear Information System (INIS)

    Dissociation constants of alkali metal monopyrocatechinborates of Me[(C6H4O2)B(OH)2]xnH2O (Me = Na+, Li+) composition are determined using conductometric method based on equivalent electric conductivity values, in methanol and ethanol at 25 deg C. Dissociation constants of weak electrolytes are calculated by the Fuoss-Kraus method. Conditions of Valden raw action are determined which connects concentrations with permittivity of medium

  5. Lattice-gas model for alkali-metal fullerides: face-centered-cubic structure

    OpenAIRE

    Udvardi, Laszlo; Szabo, Gyorgy

    1995-01-01

    A lattice-gas model is suggested for describing the ordering phenomena in alkali-metal fullerides of face-centered-cubic structure assuming the electric charge of alkali ions residing in either octahedral or tetrahedral interstitial sites is completely screened by the first-neighbor C_60 molecules. This approximation allows us to derive an effective ion-ion interaction. The van der Waals interaction between the ion and C_60 molecule is characterized by introducing an additional energy at the ...

  6. Electrohydrodynamic emission of positive and negative ions from alkali-metal halide melts

    International Nuclear Information System (INIS)

    The characteristics of electrohydrodynamic (EHD) emission of positive and negative ions from melts of alkali-metal metals are presented. The angular current density is 3-4 μA/sr with emission currents of 0.1-0.5 μA. The salt EHD sources which have been developed yield stable currents of K+, Rb+, Cs+, F-, Cl-, and I- ions for several tens of hours. 10 refs., 4 figs., 1 tab

  7. Synthesis and Characterization of Novel Ternary and Quaternary Alkali Metal Thiophosphates

    KAUST Repository

    Alahmary, Fatimah S.

    2014-05-01

    The ongoing development of nonlinear optical (NLO) crystals such as coherent mid-IR sources focuses on various classes of materials such as ternary and quaternary metal chalcophosphates. In case of thiophosphates, the connection between PS4-tetrahedral building blocks and metals gives rise to a broad structural variety where approximately one third of all known ternary (A/P/S) and quaternary (A/M/P/S) (A = alkali metal, M = metal) structures are acentric and potential nonlinear optical materials. The molten alkali metal polychalcophosphate fluxes are a well-established method for the synthesis of new ternary and quaternary thiophosphate and selenophosphate compounds. It has been a wide field of study and investigation through the last two decades. Here, the flux method is used for the synthesis of new quaternary phases containing Rb, Ag, P and S. Four new alkali metal thiophosphates, Rb4P2S10, RbAg5(PS4), Rb2AgPS4 and Rb3Ag9(PS4)4, have been synthesized successfully from high purity elements and binary starting materials. The new compounds were characterized by single crystal and powder X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), ultraviolet-visible (UV-VIS), Raman spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). These compounds show interesting structural variety and physical properties. The crystal structures feature 3D anionic framework built up of PS4 tetrahedral units and charge balanced by Ag and alkali metal cations. All prepared compounds are semiconductors with band gap between 2.3 eV to 2.6 eV and most of them are thermally stable up to 600ºC.

  8. Device and method for upgrading petroleum feedstocks and petroleum refinery streams using an alkali metal conductive membrane

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, John Howard; Alvare, Javier

    2016-09-13

    A reactor has two chambers, namely an oil feedstock chamber and a source chamber. An ion separator separates the oil feedstock chamber from the source chamber, wherein the ion separator allows alkali metal ions to pass from the source chamber, through the ion separator, and into the oil feedstock chamber. A cathode is at least partially housed within the oil feedstock chamber and an anode is at least partially housed within the source chamber. A quantity of an oil feedstock is within the oil feedstock chamber, the oil feedstock comprising at least one carbon atom and a heteroatom and/or one or more heavy metals, the oil feedstock further comprising naphthenic acid. When the alkali metal ion enters the oil feedstock chamber, the alkali metal reacts with the heteroatom, the heavy metals and/or the naphthenic acid, wherein the reaction with the alkali metal forms inorganic products.

  9. A simple alkali-metal and noble gas ion source for SIMS equipments with mass separation of the primary ions

    International Nuclear Information System (INIS)

    An alkali-metal ion source working without a store of alkali-metals is described. The alkali-metal ions are produced by evaporation of alkali salts and ionization in a low-voltage arc discharge stabilized with a noble gas plasma or in the case of small alkali-metal ion currents on the base of the well known thermic ionization at a hot tungsten wire. The source is very simple in construction and produces a stable ion current of 0.3 μA for more than 100 h. It is possible to change the ion species in a short time. This source is applicable to all SIMS equipments using mass separation for primary ions. (author)

  10. Equation of state for solid rare gases and alkali metals under pressure

    Science.gov (United States)

    Bonnet, Pierre

    2016-07-01

    This investigation is based on an atomic equation of state which takes into account the excluded volume of the atom being considered. Study of solid rare gases allows following the packing factor of the solid in equilibrium with the gas at different temperatures and of the solid and the liquid in the case of solid-liquid equilibria. The application of a pressure to the solid up to 9800 MPa allows determining the decrease in atomic volume and thus the compressibility. Such a study leads to proposing a new expression through dividing the pressure derivative (as a function of the excluded volume) by the pressure. This new coefficient is a pressure-independent constant but varies with the atom considered. Multiplied by the initial atomic volume, this coefficient has a unique value for all the rare gases. Furthermore, this is also true for the series of alkali metals with however a lower value of the coefficient. The atomic configurations of the two series are very different with one free electron for the alkali metals but closed shells for the rare gases. The alkali metals are therefore more complex than the rare gases. It is worthwhile to note that study of the equilibrium has not required the use of the principles of thermodynamics.

  11. Design of low work function materials using alkali metal-doped transition metal dichalcogenides

    Science.gov (United States)

    Kim, Sol; Lee, Man Young; Lee, Seong; Jhi, Seung-Hoon

    Engineering the work function is a key issue in surface science. Particularly, discovering the materials that have work functions less than 1eV is essential for efficient thermionic energy conversion. The lowest work function of materials, reported so far, is in a range of about 1eV. To design low work function materials, we chose MX2 (M =Mo and W; X =S, Se and Te) as substrates and alkali metals (Li, Na, K, Rb and Cs) as dopants, and studied their electronic structures, charge transfer, induced surface dipole moment, and work function using first-principles calculations. We found that the charge transfer from alkali metals to MX2 substrates decreases as the atomic radius of alkali metals increases. Regardless of the amount of the charge transfer, K on WTe2 exhibits the biggest surface dipole moment, which consequently makes the surface work function the lowest. Also, we found a correlation between the binding distance and the work function.

  12. A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium.

    Science.gov (United States)

    McCarron, Daniel J; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L

    2007-09-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D(2) transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude. PMID:17902946

  13. A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium

    International Nuclear Information System (INIS)

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D2 transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude

  14. Interactions of alkali metals and electrolyte with cathode carbons

    Energy Technology Data Exchange (ETDEWEB)

    Naas, Tyke

    1997-12-31

    The Hall-Heroult process for electrolytic reduction of alumina has been the only commercial process for production of primary aluminium. The process runs at high temperature and it is important to minimize the energy consumption. To save energy it is desirable to reduce the operating temperature. This can be achieved by adding suitable additives such as LiF or KF to the cryolitic electrolyte. This may conflict with the objective of extending the lifetime of the cathode linings of the cell as much as possible. The thesis investigates this possibility and the nature of the interactions involved. It supports the hypothesis that LiF-additions to the Hall-Heroult cell electrolyte is beneficial to the carbon cathode performance because the diminished sodium activity reduces the sodium induced stresses during the initial period of electrolysis. The use of KF as an additive is more dangerous, but the results indicate that additions up to 5% KF may be tolerated in acidic melts with semigraphitic or graphitic cathodes with little risk of cathode problems. 153 refs., 94 figs., 30 tabs.

  15. Vapor sensing with a natural photonic cell.

    Science.gov (United States)

    Mouchet, Sébastien R; Tabarrant, Tijani; Lucas, Stéphane; Su, Bao-Lian; Vukusic, Pete; Deparis, Olivier

    2016-05-30

    Photonic structures encased by a permeable envelope give rise to iridescent blue color in the scales covering the male Hoplia coerulea beetle. This structure comprises a periodic porous multilayer. The color of these scales is known for changing from blue to green upon contact with water despite the presence of the envelope. This optical system has been referred to as a photonic cell due to the role of the envelope that mediates fluid exchanges with the surrounding environment. Following from previously studied liquid-induced changes in the color appearance of H. coerulea, we measured vapor-induced color changes in its appearance. This response to vapor exposure was marked by reflectance redshift and an increase in peak reflectance intensity. Different physico-chemical processes were investigated to explain the increase in reflectance intensity, a property not usually associated with vapor-induced optical signature changes. These simulations indicated the optical response arose from physisorption of a liquid film on the beetle scales followed by liquid penetration through the envelope and the filling of micropores within the body of the photonic structure. PMID:27410142

  16. Shortcuts for understanding rovibronic spectroscopy of ultracold alkali metal diatomic molecules

    Science.gov (United States)

    Stwalley, William C.; Bellos, Michael; Carollo, Ryan; Banerjee, Jayita; Bermudez, Matthew

    2012-08-01

    The high-resolution rovibronic spectroscopies of cold and ultracold molecules (e.g. supersonic molecular beam excitation spectra (MB), photoassociation spectra of ultracold atoms (PA), resonance-enhanced multiphoton ionization spectra (REMPI), stimulated Raman transfer (SRT) spectra) are of major current interest. This manuscript summarizes the significant level of understanding of these various spectroscopies, enabled by using simple graphical and semiclassical ideas and shortcuts. Physical realizations of these spectroscopies will be illustrated using the alkali metal diatomic molecules, both homonuclear (e.g. Rb2) and heteronuclear (e.g. KRb).

  17. Van der Waals coefficients for alkali metal clusters and their size dependence

    Indian Academy of Sciences (India)

    Arup Banerjee; Manoj K Harbola

    2006-02-01

    In this paper we employ the hydrodynamic formulation of time-dependent density functional theory to obtain the van der Waals coefficients 6 and 8 of alkali metal clusters of various sizes including very large clusters. Such calculations become computationally very demanding in the orbital-based Kohn-Sham formalism, but are quite simple in the hydrodynamic approach. We show that for interactions between the clusters of the same sizes, 6 and 8 scale as the sixth and the eighth power of the cluster radius, respectively, and approach their classically predicted values for the large size clusters.

  18. Behavior of Alkali Metals and Ash in a Low-Temperature Circulating Fluidized Bed (LTCFB) Gasifier

    DEFF Research Database (Denmark)

    Narayan, Vikas; Jensen, Peter Arendt; Henriksen, Ulrik Birk;

    2016-01-01

    , the low reactor temperature ensures that high-alkali biomass fuels canbe used without risk of bed defluidization. This paper presents the first investigation of the fate of alkali metals and ash in lowtemperaturegasifiers. Measurements on bed material and product gas dust samples were made on a 100 k......A low-temperature circulating fluidized bed system (LTCFB) gasifier allows for pyrolysis and gasification to occurat low temperatures, thereby improving the retention of alkali and other inorganic elements within the system and minimizingthe amount of ash species in the product gas. In addition...

  19. Electric dipole polarizabilities of Rydberg states of alkali-metal atoms

    Science.gov (United States)

    Yerokhin, V. A.; Buhmann, S. Y.; Fritzsche, S.; Surzhykov, A.

    2016-09-01

    Calculations of the static electric-dipole scalar and tensor polarizabilities are presented for two alkali-metal atoms, Rb and Cs, for the n S , n P½,3 /2 , and n D3 /2 ,5 /2 states with large principal quantum numbers up to n =50 . The calculations are performed within an effective one-electron approximation, based on the Dirac-Fock Hamiltonian with a semiempirical core-polarization potential. The obtained results are compared with those from a simpler semiempirical approach and with available experimental data.

  20. Half metallic ferromagnetism in alkali metal nitrides MN (M = Rb, Cs): A first principles study

    Energy Technology Data Exchange (ETDEWEB)

    Murugan, A., E-mail: rrpalanichamy@gmail.com; Rajeswarapalanichamy, R., E-mail: rrpalanichamy@gmail.com; Santhosh, M., E-mail: rrpalanichamy@gmail.com; Sudhapriyanga, G., E-mail: rrpalanichamy@gmail.com [Department of Physics, N.M.S.S.V.N College, Madurai, Tamilnadu-625019 (India); Kanagaprabha, S. [Department of Physics, Kamaraj College, Tuticorin, Tamil Nadu-628003 (India)

    2014-04-24

    The structural, electronic and elastic properties of two alkali metal nitrides (MN: M= Rb, Cs) are investigated by the first principles calculations based on density functional theory using the Vienna ab-initio simulation package. At ambient pressure the two nitrides are stable in ferromagnetic state with CsCl structure. The calculated lattice parameters are in good agreement with the available results. The electronic structure reveals that these materials are half metallic in nature. A pressure-induced structural phase transition from CsCl to ZB phase is observed in RbN and CsN.

  1. Characteristic thermoluminescence of gamma-irradiated alumina ceramics doped with some alkali metals

    Science.gov (United States)

    Henaish, B. A.; El-Agrami, A. M.; Abdel-Fattah, W. I.; Osiris, W. G.

    1994-07-01

    Thermoluminescence properties of pure Al2O3-ceramic discs doped with some oxides of alkali metals and B were investigated. Two groups of samples were studied: one with a low concentration of B and alkali oxides and the other with higher concentration. The first group shows a relatively higher stability and better reproducibility for γ-radiation and neutron-induced TL, which could be utilized in mixed radiation field dosimetry. The main disadvantage of these TL-materials is the relatively high rate of signal fading. A simple course of post irradiation heat annealing is proposed to overcome this drawback.

  2. Understanding the insulating nature of alkali-metal/Si(111):B interfaces.

    Science.gov (United States)

    Fagot-Revurat, Y; Tournier-Colletta, C; Chaput, L; Tejeda, A; Cardenas, L; Kierren, B; Malterre, D; Le Fèvre, P; Bertran, F; Taleb-Ibrahimi, A

    2013-03-01

    We have recently revisited the phase diagram of alkali-metal/Si(111):B semiconducting interfaces previously suggested as the possible realization of a Mott-Hubbard insulator on a triangular lattice. The insulating character of the 2√[3] × 2√[3]R30 surface reconstruction observed at the saturation coverage, i.e. 0.5 ML, has been shown to find its origin in a giant alkali-metal-induced vertical distortion. Low energy electron diffraction, photoemission spectroscopy and scanning tunneling microscopy and spectroscopy experiments coupled with linear augmented plane-wave density functional theory calculations allow a full understanding of the k-resolved band structure, explaining both the inhomogeneous charge transfers into an Si-B hybridized surface state and the opening of a band gap larger than 1 eV. Moreover, √[3] × √[3]R30, 3 × 3 and 2√[3] × 2√[3]R30 surface reconstructions observed as a function of coverage may reveal a filling-controlled transition from a half-filled correlated magnetic material to a strongly distorted band insulator at saturation. PMID:23400003

  3. Enthalpic Interaction for α-Amino Acid with Alkali Metal Halides in Water

    Institute of Scientific and Technical Information of China (English)

    LU,Yan(卢雁)

    2004-01-01

    The studies of the enthalpic interaction parameters, hxy, hxyy and hxxv, of alkali metal halides with glycine,α-alanine and α-aminobutyric acid were published. Synthetic considering of the results of the studies, some interesting behaviors of the interaction between alkali metal halides and the α-amino acids have been found. The values of hxy will increase with the increase of the number of carbon atoms in alkyl side chain of amino acid molecules and decrease with the increase of the radius of the ions. The increasing of the salt's effect on the hydrophobic hydration structure as the radii of anion is more obvious than as that of cation. The value of hxxy will regularly decrease with the increase of the number of carbon atoms in the alkyl chain of amino acids and linear increase with the increase of the radius. But the relation of hxxy with the radius of cations is not evident. The value of hxyy will increase with the increase of the radii of the ions. As the increase of the number of carbon atoms of amino acids, hxyy is decreas for the ions which have lager size and there is a maximum value at α-alanine for the ions which have small size. The behaviors of the interaction mentioned above were further discussed in view of electrostatic and structural interactions.

  4. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    None

    1992-11-01

    The Hanford Site, located northwest of the city of Richland, Washington, houses reactors, chemical-separation systems, and related facilities used for the production of special nuclear materials, as well as for activities associated with nuclear energy development. The 300 Area of the Hanford Site contains reactor fuel manufacturing facilities and several research and development laboratories. The 3718-F Alkali Metal Treatment and Storage Facility (3718-F Facility), located in the 300 Area, was used to store and treat alkali metal wastes. Therefore, it is subject to the regulatory requirements for the storage and treatment of dangerous wastes. Closure will be conducted pursuant to the requirements of the Washington Administrative Code (WAC) 173-303-610 (Ecology 1989) and 40 CFR 270.1. Closure also will satisfy the thermal treatment facility closure requirements of 40 CFR 265.381. This closure plan presents a description of the 3718-F Facility, the history of wastes managed, and the approach that will be followed to close the facility. Only hazardous constituents derived from 3718-F Facility operations will be addressed.

  5. Effect of particle size on thermal decomposition of alkali metal picrates

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Rui; Zhang, Tonglai, E-mail: ztlbit@bit.edu.cn; Yang, Li; Zhou, Zunning

    2014-05-01

    Graphical abstract: The smaller-sized picrate has greater gas emission than do its larger counterpart. The small size effect reduces the thermal decomposition activation energy, accelerates the reaction rate, and promotes the reaction activity. - Highlights: • Picrates were prepared into three micron sizes by microemulsion synthesis. • Thermal decomposition kinetics and thermodynamics were studied by DPTA and DSC. • Smaller-sized picrate has higher activity and faster reaction rate. • Particle size effect on thermal decomposition kinetics and thermodynamics was revealed. - Abstract: Three alkali metal picrates, KPA, RbPA and CsPA, were prepared into three micron sizes by microemulsion synthesis, and their thermal decomposition behaviors were investigated by DPTA at different temperatures and by DSC at different heating rates. The smaller-sized picrate has greater gas emission and smaller kinetic and thermodynamic parameters than do its larger counterpart. It can be attributed to the decreasing particle size which leads to the high surface energy, the fast mass and heat transfer, and the increasing active sites on the reaction interface. The small size effect and surface effect cause the autocatalysis which reduces the activation energy and promotes the reaction activity. The particle size does not affect the reaction mechanism. However, the picrates with different central alkali metals exhibit different reaction mechanisms even though they are of the same size. This is because the central metal determines the bond energy and consequently affects the stability of picrate.

  6. A heated vapor cell unit for DAVLL in atomic rubidium

    CERN Document Server

    McCarron, Daniel J; Tierney, Patrick; Cornish, Simon L

    2007-01-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D2 transitions in atomic rubidium is described. A 5 cm-long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude.

  7. The influence of chlorine on the fate and activity of alkali metals during the gasification of wood

    Energy Technology Data Exchange (ETDEWEB)

    Struis, R.; Scala, C. von; Schuler, A.; Stucki, S. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Chlorine clearly inhibits the CO{sub 2}-gasification reaction of charcoal at 800{sup o}C. From this and other observations the picture emerges that the reduction in the gasification reactivity of the charcoal is intimately related to the deactivation of the catalytically active alkali metals residing in the wood due to the formation of the chloride salt. It is argued that the heavy metal chlorides will likely transfer the chlorine to the indigenous alkali metals during the pyrolysis stage of the wood. The fate of the thus formed alkali metal chlorides can then be either their removal from the sample (evaporation), or, when present at the gasification stage, re-activation (i.e., de-chlorination) under our gasification conditions. (author) 3 figs., 4 refs.

  8. Ab initio interaction potentials and scattering lengths for ultracold mixtures of metastable helium and alkali-metal atoms

    Science.gov (United States)

    Kedziera, Dariusz; Mentel, Łukasz; Żuchowski, Piotr S.; Knoop, Steven

    2015-06-01

    We have obtained accurate ab initio +4Σ quartet potentials for the diatomic metastable triplet helium+alkali-metal (Li, Na, K, Rb) systems, using all-electron restricted open-shell coupled cluster singles and doubles with noniterative triples corrections CCSD(T) calculations and accurate calculations of the long-range C6 coefficients. These potentials provide accurate ab initio quartet scattering lengths, which for these many-electron systems is possible, because of the small reduced masses and shallow potentials that result in a small amount of bound states. Our results are relevant for ultracold metastable triplet helium+alkali-metal mixture experiments.

  9. Diffusion of alkali metals in the first stage graphite intercalation compounds by vdW-DFT calculations

    OpenAIRE

    Wang, Zhaohui; Ratvik, Arne Petter; Grande, Tor; Selbach, Sverre Magnus

    2015-01-01

    Diffusion of alkali metal cations in the first stage graphite intercalation compounds (GIC) LiC6, NaC6, NaC8 and KC8 has been investigated with density functional theory (DFT) calculations using the optPBE-vdW van der Waals functional. The formation energies of alkali vacancies, interstitials and Frenkel defects were calculated and vacancies were found to be the dominating point defects. The diffusion coefficients of the alkali metals in GIC were evaluated by a hopping model of point defects ...

  10. Prospects for sympathetic cooling of polar molecules: NH with alkali-metal and alkaline-earth atoms - a new hope

    CERN Document Server

    Soldán, Pavel; Hutson, Jeremy M

    2009-01-01

    We explore the potential energy surfaces for NH molecules interacting with alkali-metal and alkaline-earth atoms using highly correlated ab-initio electronic structure calculations. The surfaces for interaction with alkali-metal atoms have deep wells dominated by covalent forces. The resulting strong anisotropies will produce strongly inelastic collisions. The surfaces for interaction with alkaline-earth atoms have shallower wells that are dominated by induction and dispersion forces. For Be and Mg the anisotropy is small compared to the rotational constant of NH, so that collisions will be relatively weakly inelastic. Be and Mg are thus promising coolants for sympathetic cooling of NH to the ultracold regime.

  11. New bonding configuration on Si(111) and Ge(111) surfaces induced by the adsorption of alkali metals

    DEFF Research Database (Denmark)

    Lottermoser, L.; Landemark, E.; Smilgies, D.M.;

    1998-01-01

    The structure of the (3×1) reconstructions of the Si(111) and Ge(111) surfaces induced by adsorption of alkali metals has been determined on the basis of surface x-ray diffraction and low-energy electron diffraction measurements and density functional theory. The (3×1) surface results primarily...... from the substrate reconstruction and shows a new bonding configuration consisting of consecutive fivefold and sixfold Si (Ge) rings in 〈11̅ 0〉 projection separated by channels containing the alkali metal atoms. © 1998 The American Physical Society...

  12. A heated vapor cell unit for DAVLL in atomic rubidium

    OpenAIRE

    McCarron, Daniel J.; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L.

    2007-01-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D2 transitions in atomic rubidium is described. A 5 cm-long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field...

  13. Characterization of Bioeffects on Endothelial Cells under Acoustic Droplet Vaporization.

    Science.gov (United States)

    Seda, Robinson; Li, David S; Fowlkes, J Brian; Bull, Joseph L

    2015-12-01

    Gas embolotherapy is achieved by locally vaporizing microdroplets through acoustic droplet vaporization, which results in bubbles that are large enough to occlude blood flow directed to tumors. Endothelial cells, lining blood vessels, can be affected by these vaporization events, resulting in cell injury and cell death. An idealized monolayer of endothelial cells was subjected to acoustic droplet vaporization using a 3.5-MHz transducer and dodecafluoropentane droplets. Treatments included insonation pressures that varied from 2 to 8 MPa (rarefactional) and pulse lengths that varied from 4 to 16 input cycles. The bubble cloud generated was directly dependent on pressure, but not on pulse length. Cellular damage increased with increasing bubble cloud size, but was limited to the bubble cloud area. These results suggest that vaporization near the endothelium may impact the vessel wall, an effect that could be either deleterious or beneficial depending on the intended overall therapeutic application.

  14. Separation of hafnium from zirconium in their tetrachloride solution in molten alkali metal chlorides

    Energy Technology Data Exchange (ETDEWEB)

    Salyulev, A.B.; Kudyakov, V.Ya.; Smirnov, M.V.; Moskalenko, N.I. (AN SSSR, Sverdlovsk. Inst. Ehlektrokhimii)

    1984-08-01

    The coefficient of HfCl/sub 4/ and ZrCl/sub 4/ separation in the process of vapour sublimation from their solutions in molten NaCl, KCl, CsCl, NaCl-KCl and NaCl-CsCl equimolar mixtures is found to vary in the series from approximately 1.10 to approximately 1.22 and practically not to depend on the temperature (in the 600-910 deg) range and concentration (2-25 mol.% ZrCl/sub 4/+HfCl/sub 4/). HfCl/sub 4/ and ZrCl/sub 4/ are shown to form almost perfect solutions with each other, which in their turn form imperfect solutions with molten alkali metal chlorides, with the strength of hafnium complex chloride anions increasing higher than that of zirconium in the series from NaCl to CsCl.

  15. Separation of hafnium from zirconium in their tetrachloride solution in molten alkali metal chlorides

    International Nuclear Information System (INIS)

    The coefficient of HfCl4 and ZrCl4 separation in the process of vapour sublimation from their solutions in molten NaCl, KCl, CsCl, NaCl-KCl and NaCl-CsCl equimolar mixtures is found to vary in the series from approximately 1.10 to approximately 1.22 and practically not to depend on the temperature (in the 600-910 deg) range and concentration (2-25 mol.% ZrCl4+HfCl4). HfCl4 and ZrCl4 are shown to form almost perfect solutions with each other, which in their turn form imperfect solutions with molten alkali metal chlorides, with the strength of hafnium complex chloride anions increasing higher than that of zirconium in the series from NaCl to CsCl

  16. First-principles study of d0 ferromagnetism in alkali-metal doped GaN

    Science.gov (United States)

    Zhang, Yong

    2016-08-01

    The d0 ferromagnetism in GaN has been studied based on density functional theory. Our results show that GaN with sufficient hole become spin-polarized. Alkali-metal doping can introduce holes in GaN. Among them, both of Li- and Na-doping induce ferromagnetism in GaN and Na-doped GaN behaves as half-metallic ferromagnet. Moreover, at a growth temperature of 2000 K under N-rich condition, both concentrations can exceed 18%, which is sufficient to produce detectable macroscopic magnetism in GaN. The Curie temperature of Li- and Na-doped GaN is estimated to be 304 and 740 K, respectively, which are well above room temperature.

  17. The alkali metal thermoelectric converter /AMTEC/ - A new direct energy conversion technology for aerospace power

    Science.gov (United States)

    Bankston, C. P.; Cole, T.; Jones, R.; Ewell, R.

    1982-01-01

    A thermally regenerative electrochemical device for the direct conversion of heat to electrical energy, the alkali metal thermoelectric converter (AMTEC), is characterized by potential efficiencies on the order of 15-40% and possesses no moving parts, making it a candidate for space power system applications. Device conversion efficiency is projected on the basis of experimental voltage vs current curves exhibiting power densities of 0.7 W/sq cm and measured electrode efficiencies of up to 40%. Preliminary radiative heat transfer measurements presented may be used in an investigation of methods for the reduction of AMTEC parasitic radiation losses. AMTEC assumes heat input and rejection temperatures of 900-1300 K and 400-800 K, respectively. The working fluid is liquid sodium, and the porous electrode employed is of molybdenum.

  18. Secondary transformation mechanism of paramagnetic centers in irradiated alkali metal perchlorates

    International Nuclear Information System (INIS)

    The EPR method has been used to study thermal transformations of paramagnetic centres (PC) in X-ray irradiated potassium, rubidium and cesium perchlorates. Experimental data make it possible to suppose that diffusion coefficient of O- ion a rather high and this ion is freely diffused already at 262 K. Colliding with [MeClO4]+ centres it is transformed in a molecule of oxygen. Another part of O- is transformed in stable ozonide-ion at 300 K. About room temperature hole centres dissociate with formation of ClO2 radical. It is supposed that part of electron and hole centres is not stabilized but at 77 K it is transformed in stable radiolysis products. This process most effective proceeds in dislocations and on the surface of microcrystals. The suggested model of thermal transformations of primary PC in irradiated perchlorates of alkali metals explains formation of all the finite ion and paramagnetic radiolysis products

  19. Ternary Amides Containing Transition Metals for Hydrogen Storage: A Case Study with Alkali Metal Amidozincates.

    Science.gov (United States)

    Cao, Hujun; Richter, Theresia M M; Pistidda, Claudio; Chaudhary, Anna-Lisa; Santoru, Antonio; Gizer, Gökhan; Niewa, Rainer; Chen, Ping; Klassen, Thomas; Dornheim, Martin

    2015-11-01

    The alkali metal amidozincates Li4 [Zn(NH2)4](NH2)2 and K2[Zn(NH2)4] were, to the best of our knowledge, studied for the first time as hydrogen storage media. Compared with the LiNH2-2 LiH system, both Li4 [Zn(NH2)4](NH2)2-12 LiH and K2[Zn(NH2)4]-8 LiH systems showed improved rehydrogenation performance, especially K2[Zn(NH2)4]-8 LiH, which can be fully hydrogenated within 30 s at approximately 230 °C. The absorption properties are stable upon cycling. This work shows that ternary amides containing transition metals have great potential as hydrogen storage materials.

  20. 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.

  1. The role of alkali metal cations in the stabilization of guanine quadruplexes: why K(+) is the best.

    Science.gov (United States)

    Zaccaria, F; Paragi, G; Fonseca Guerra, C

    2016-08-21

    The alkali metal ion affinity of guanine quadruplexes has been studied using dispersion-corrected density functional theory (DFT-D). We have done computational investigations in aqueous solution that mimics artificial supramolecular conditions where guanine bases assemble into stacked quartets as well as biological environments in which telomeric quadruplexes are formed. In both cases, an alkali metal cation is needed to assist self-assembly. Our quantum chemical computations on these supramolecular systems are able to reproduce the experimental order of affinity of the guanine quadruplexes for the cations Li(+), Na(+), K(+), Rb(+), and Cs(+). The strongest binding is computed between the potassium cation and the quadruplex as it occurs in nature. The desolvation and the size of alkali metal cations are thought to be responsible for the order of affinity. Until now, the relative importance of these two factors has remained unclear and debated. By assessing the quantum chemical 'size' of the cation, determining the amount of deformation of the quadruplex needed to accommodate the cation and through the energy decomposition analysis (EDA) of the interaction energy between the cation and the guanines, we reveal that the desolvation and size of the alkali metal cation are both almost equally responsible for the order of affinity. PMID:27185388

  2. Alkali metal salts of formazanate ligands : diverse coordination modes as a result of the nitrogen-rich [NNCNN] ligand backbone

    NARCIS (Netherlands)

    Travieso-Puente, Raquel; Chang, Mu-Chieh; Otten, Edwin

    2014-01-01

    Alkali metal salts of redox-active formazanate ligands were prepared, and their structures in the solid-state and in solution are determined. The nitrogen-rich [NNCNN] backbone of formazanates results in a varied coordination chemistry, with both the internal and terminal nitrogen atoms available fo

  3. Electric dipole polarizabilities at imaginary frequencies for the alkali-metal, alkaline-earth, and inert gas atoms

    CERN Document Server

    Derevianko, Andrei; Babb, James F

    2009-01-01

    The electric dipole polarizabilities evaluated at imaginary frequencies for hydrogen, the alkali-metal atoms, the alkaline earth atoms, and the inert gases are tabulated along with the resulting values of the atomic static polarizabilities, the atom-surface interaction constants, and the dispersion (or van der Waals) constants for the homonuclear and the heteronuclear diatomic combinations of the atoms.

  4. Synthesis and Selective Coloration of Monoaza Crown Ethers Bearing Picrylamino-type Side Arms for Alkali Metal Salts and Methylamine

    Institute of Scientific and Technical Information of China (English)

    Wei ZENG; Zhi Hua MAO; Mi GONG; Chun Chun ZHANG; Sheng Ying QIN; Jun SU

    2003-01-01

    N-pivot lariat ethers with picrylamino group as a chromophore (1, 2 and 3) have been prepared by reaction of N-(4-aminoaryl)monoaza crown ethers with picryl chrolide, and the selective coloration of 1, 2 and 3 for alkali metal salts and amines has been studied by UV-Vis spectra.

  5. LDA or GGA? A combined experimental inelastic neutron scattering and ab initio lattice dynamics study of alkali metal hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, G.D. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Departamento de Quimica, Universidad Nacional de la Patagonia SJB, Ciudad Universitaria, 9005 Comodoro Rivadavia (Argentina); Colognesi, D. [Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via Madonna del Piano s.n.c., 50019 Sesto Fiorentino (Finland) (Italy); Mitchell, P.C.H. [School of Chemistry, University of Reading, RG6 6AD (United Kingdom); Ramirez-Cuesta, A.J. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); School of Chemistry, University of Reading, RG6 6AD (United Kingdom)], E-mail: a.j.ramirez-cuesta@rl.ac.uk

    2005-10-31

    In a previous work, we carried out inelastic neutron scattering (INS) spectroscopy experiments and preliminary first principles calculations on alkali metal hydrides. The complete series of alkali metal hydrides, LiH, NaH, KH, RbH and CsH was measured in the high-resolution TOSCA INS spectrometer at ISIS. Here, we present the results of ab initio electronic structure calculations of the properties of the alkali metal hydrides using both the local density approximation (LDA) and the generalized gradient approximation (GGA), using the Perdew-Burke-Ernzerhof (PBE) parameterization. Properties calculated were lattice parameters, bulk moduli, dielectric constants, effective charges, electronic densities and inelastic neutron scattering (INS) spectra. We took advantage of the currently available computer power to use full lattice dynamics theory to calculate thermodynamic properties for these materials. For the alkali metal hydrides (LiH, NaH, KH, RbH and CsH) using lattice dynamics, we found that the INS spectra calculated using LDA agreed better with the experimental data than the spectra calculated using GGA. Both zero-point effects and thermal contributions to free energies had an important effect on INS and several thermodynamic properties.

  6. Thermochemical ablation therapy of VX2 tumor using a permeable oil-packed liquid alkali metal.

    Directory of Open Access Journals (Sweden)

    Ziyi Guo

    Full Text Available Alkali metal appears to be a promising tool in thermochemical ablation, but, it requires additional data on safety is required. The objective of this study was to explore the effectiveness of permeable oil-packed liquid alkali metal in the thermochemical ablation of tumors.Permeable oil-packed sodium-potassium (NaK was prepared using ultrasonic mixing of different ratios of metal to oil. The thermal effect of the mixture during ablation of muscle tissue ex vivo was evaluated using the Fluke Ti400 Thermal Imager. The thermochemical effect of the NaK-oil mixture on VX2 tumors was evaluated by performing perfusion CT scans both before and after treatment in 10 VX2 rabbit model tumors. VX2 tumors were harvested from two rabbits immediately after treatment to assess their viability using trypan blue and hematoxylin and eosin (H.E. staining.The injection of the NaK-oil mixture resulted in significantly higher heat in the ablation areas. The permeable oil controlled the rate of heat released during the NaK reaction with water in the living tissue. Perfusion computed tomography and its parameter map confirmed that the NaK-oil mixture had curative effects on VX2 tumors. Both trypan blue and H.E. staining showed partial necrosis of the VX2 tumors.The NaK-oil mixture may be used successfully to ablate tumor tissue in vivo. With reference to the controlled thermal and chemical lethal injury to tumors, using a liquid alkali in ablation is potentially an effective and safe method to treat malignant tumors.

  7. Thermodynamic study of alkali metals release in pressurised fluidised-bed combustion and gasification of peat

    Energy Technology Data Exchange (ETDEWEB)

    Mojtahedi, W.; Backman, R.; Korhonen, M.

    1988-01-01

    A combined-cycle power generation system incorporating pressurised fluidised-bed combustion (PFBC) or gasification is considered a promising approach for electricity generation using solid fuels such as peat. In these systems, the high-pressure hot flue gas is expanded in a gas turbine. Peat contains sodium and potassium which are released in combustion and gasification. These are corrosive elements that can cause severe damage to the turbine blades if not suppressed. Multicomponent, multiphase equilibrium calculations were carried out for atmospheric and pressurised fluidised-bed operating conditions to determine the relative distribution of the two metals (Na and K) in the gas and condensed phases. Dependence of the alkali volatilisation on the operating temperature, pressure, the chlorine-content and the total alkali-content of the feedstock was studied. The results show that the alkali release in the vapour-phase could be much higher than acceptable to a gas turbine, particularly under gasification conditions. Hence the necessity to remove the volatilised alkali-metal compounds is more acute in gasification than in combustion. Both sodium and potassium are present as chlorides and to a lesser extent as hydroxides in the gas phase in both modes of operation (i.e. combustion and gasification). However, whereas under combustion conditions both metals seem to condense as sulphates (Na/sub 2/SO4 and K/sub 2/SO4), in gasification, chlorides and carbonates dominate in the condensed phase. The alkali-metals volatilisation shows strong dependence on the operating pressure of the system as well as on the chlorine-content of the feedstock. It decreases markedly with the former but increases sharply with the latter.

  8. Structural and Dynamical Trends in Alkali-Metal Silanides Characterized by Neutron-Scattering Methods

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Wan Si; Dimitrievska, Mirjana; Chotard, Jean-Noel; Zhou, Wei; Janot, Raphael; Skripov, Alexander V.; Udovic, Terrence J.

    2016-09-29

    Structural, vibrational, and dynamical properties of the mono- and mixed-alkali silanides (MSiH3, where M = K, Rb, Cs, K0.5Rb0.5, K0.5Cs0.5, and Rb0.5Cs0.5) were investigated by various neutron experiments, including neutron powder diffraction (NPD), neutron vibrational spectroscopy (NVS), neutron-scattering fixed-window scans (FWSs), and quasielastic neutron scattering (QENS) measurements. Structural characterization showed that the mixed compounds exhibit disordered (..alpha..) and ordered (..beta..) phases for temperatures above and below about 200-250 K, respectively, in agreement with their monoalkali correspondents. Vibrational and dynamical properties are strongly influenced by the cation environment; in particular, there is a red shift in the band energies of the librational and bending modes with increasing lattice size as a result of changes in the bond lengths and force constants. Additionally, slightly broader spectral features are observed in the case of the mixed compounds, indicating the presence of structural disorder caused by the random distribution of the alkali-metal cations within the lattice. FWS measurements upon heating showed that there is a large increase in reorientational mobility as the systems go through the order-disorder (..beta..-..alpha..) phase transition, and measurements upon cooling of the ..alpha..-phase revealed the known strong hysteresis for reversion back to the ..beta..-phase. Interestingly, at a given temperature, among the different alkali silanide compounds, the relative reorientational mobilities of the SiH3- anions in the ..alpha..- and ..beta..-phases tended to decrease and increase, respectively, with increasing alkali-metal mass. This dynamical result might provide some insights concerning the enthalpy-entropy compensation effect previously observed for these potentially promising hydrogen storage materials.

  9. Adsorption of alkali metal atoms on germanene: A first-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Qing, E-mail: pangqingjkd@163.com [College of Science, Xi’an University of Architecture and Technology, Xi’an 710055, Shaanxi (China); Zhang, Chun-ling; Li, Long; Fu, Zhi-qiang [College of Science, Xi’an University of Architecture and Technology, Xi’an 710055, Shaanxi (China); Wei, Xiu-mei [College of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062, Shaanxi (China); Song, Yu-ling [College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang 473061, Henan (China)

    2014-09-30

    Highlights: • All alkali metal (AM) atoms considered prefer to bind on the hexagonal hollow site of germanene. • AM adsorption makes the semimetallic germanene become to be metallic. • A small band gap opens at Dirac point for AM/germanene system without degrading of electronic properties. • The band gap and charge carriers for AM/germanene system can be tuned by changing the AM coverage. • AM/germanene systems show potential applications in germanene based field effect transistors. - Abstract: The structural, energetic and electronic properties of alkali metal (AM) atoms (including Li, Na and K) adsorbed germanene with a wide range of coverages are investigated by means of first-principles calculations. All AM atoms we considered prefer to bind on the hexagonal hollow site of germanene. In contrast to graphene, the interaction between adatom and germanene surface is quite strong due to its buckled hexagonal structure. As the increasing adatom coverage, the binding between AM atom and germanene sheet is weakened, due to the enhanced adatom–adatom repulsion while the decreased adatom-germanene attraction at high coverage. As a consequence of heavy charge transfer from AM to germanene, the formed adatom–Ge bonds perform mainly an ionic character. Through adsorption, the semimetallic germanene becomes to be metallic with its Dirac point moving below the Fermi level, thus making germanene behave as n-type doped. In addition, a small band gap can be opened at the Dirac point, and both the band gap and the concentration of charge carries of AM/germanene system can be tuned by controlling the adatom coverage. The strong binding of AM adatoms to germanene and the rich electronic properties of the AM/germanene systems suggest possible potential applications in germanene based field effect transistor (FET) devices.

  10. Characterization of Adsorbed Alkali Metal Ions in 2:1 Type Clay Minerals from First-Principles Metadynamics.

    Science.gov (United States)

    Ikeda, Takashi; Suzuki, Shinichi; Yaita, Tsuyoshi

    2015-07-30

    Adsorption states of alkali metal ions in three kinds of 2:1 type clay minerals are systematically investigated via first-principles-based metadynamics. Our reconstructed free energy surfaces in a two-dimensional space of coordination numbers specifically employed as collective variables for describing the interlayer cations show that an inner-sphere (IS) complex is preferentially formed for Cs(+) in the 2:1 type trioctahedral clay minerals with saponite-like compositions, where lighter alkali metal ions show a tendency to form an outer-sphere one instead. The strong preference for an IS complex observed for Cs(+) is found to result partially from the capability of recognizing selectively Cs(+) ions at the basal O atoms with the Lewis basicity significantly enhanced by the isomorphic substitution in tetrahedral sheets.

  11. Study of complex amalgams containing alkali metals by method of broken thermometric titration

    International Nuclear Information System (INIS)

    Complex potassium-cadmium and sodium-cadmium amalgams containing different amounts of the alkali metal nad cadmium have been studied by thermometric titration with mercury. The experiments have been carried out in argon atmosphere at 25 deg C. As evidenced by the titration of sodium-cadmium amalgams, in the range of concentrations studied (Csub(Na)=0.71-2.95, Csub(Cd)=4.38-6.45 g-at/lHg) no solid phase is formed in them. Potassium-cadmium amalgams where the metals content is no higher than their individual solubility in mercury, display, when being mercury-titrated, negative heat effects due to solid phase formation. An estimation is made of the solid phase composition, its solubility in mercury and the heat of dissolution. The solid phase appearing in complex K-Cd amalgams is likely to contain K and Cd in a ratio 1:1 its conventional solubility product is 5.4 g-at/l Hg, and the heat of dissolution in mercury at 25 deg is -21 +-4 kJ/g-at

  12. Stability of alkali-metal hydrides: effects of n-type doping

    Science.gov (United States)

    Olea Amezcua, Monica Araceli; de La Peña Seaman, Omar; Rivas Silva, Juan Francisco; Heid, Rolf; Bohnen, Klaus-Peter

    Metal hydrides could be considered ideal solid-state hydrogen storage systems, they have light weight and high hydrogen volumetric densities, but the hydrogen desorption process requires excessively high temperatures due to their high stability. Efforts have been performed to improve their dehydrogenation properties, based on the introduction of defects, impurities and doping. We present a systematic study of the n-type (electronic) doping effects on the stability of two alkali-metal hydrides: Na1-xMgxH and Li1-xBexH. These systems have been studied within the framework of density functional perturbation theory, using a mixed-basis pseudopotential method and the self-consistent version of the virtual crystal approximation to model the doping. The full-phonon dispersions are analyzed for several doping content, paying special attention to the crystal stability. It is found a doping content threshold for each system, where they are close to dynamical instabilities, which are related to charge redistribution in interstitial zones. Applying the quasiharmonic approximation, the vibrational free energy, the linear thermal expansion and heat capacities are obtained for both hydrides systems and are analyzed as a function of the doping content. This work is partially supported by the VIEP-BUAP 2016 and CONACYT-México (No.221807) projects.

  13. Study of Spectral Character of Alkali Metals Using Microwave Plasma Torch Simultaneous Spectrometer

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A microwave plasma torch(MPT) simultaneous spectrometer was used to study the spectral character and the matrix effect on alkali metal ions in solution. The main parameters were optimized. The microwave forward power was 100 W. The argon flow rate that was used to sustain the Ar-MPT included the flow rate of carrier gas and the flow rate of support gas, which were 0.8 and 1.0 L/min, respectively. The HCl concentration in the solution was 0.02 mol/L. The observation height was 9.0 mm. The detection limits of Li, Na, K, Rb, and Cs were 0.0003, 0.0004, 0.009, 0.07 and2.4 mg/L, respectively, and the results obtained by the Ar-MPT were compared with those obtained by argon inductively coupled plasma(Ar-ICP) and argon microwave induced plasma(Ar-MIP). The interference effects of several matrix elements were also studied.

  14. Elucidating the magnetic and superconducting phases in the alkali metal intercalated iron chalcogenides

    Science.gov (United States)

    Wang, Meng; Yi, Ming; Tian, Wei; Bourret-Courchesne, Edith; Birgeneau, Robert J.

    2016-02-01

    The complex interdigitated phases have greatly frustrated attempts to document the basic features of the superconductivity in the alkali metal intercalated iron chalcogenides. Here, using elastic neutron scattering, energy-dispersive x-ray spectroscopy, and resistivity measurements, we elucidate the relations of these phases in RbxFeySe2 -zSz . We find (i) the iron content is crucial in stabilizing the stripe antiferromagnetic (AF) phase with rhombic iron vacancy order (y ≈1.5 ) , the block AF phase with √{5 }×√{5 } iron vacancy order (y ≈1.6 ) , and the iron vacancy-free phase (y ≈2 ) ; and (ii) the iron vacancy-free superconducting phase (z =0 ) evolves into an iron vacancy-free metallic phase with sulfur substitution (z >1.5 ) due to the progressive decrease of the electronic correlation strength. Both the stripe AF phase and the block AF phase are Mott insulators. The iron-rich compounds (y >1.6 ) undergo a first order transition from an iron vacancy disordered phase at high temperatures into the √{5 }×√{5 } iron vacancy ordered phase and the iron vacancy-free phase below Ts. Our data demonstrate that there are miscibility gaps between these three phases. The existence of the miscibility gaps in the iron content is a key to understanding the relationship between these complicated phases.

  15. Luminescence properties of alkali metal ions sensitized CaFCl:Tb3+ nanophosphors

    Institute of Scientific and Technical Information of China (English)

    林林; 林慧; 王哲哲; 郑标; 谌基兴; 徐森元; 冯卓宏; 郑志强

    2015-01-01

    A series of CaFCl:Tb3+ and CaFCl:Tb3+,A+ (A=Li, Na and K) nanophosphors were synthesized by the one-step sol-gel method, which were reported for the first time. The sample consisted of monodisperse particles, the average size of which was 37 nm. The emissions of Tb3+ ions and oxygen defects OF? were demonstrated in the CaFCl:Tb3+ samples. The former was made up of sev-eral peaks at 488, 545, 587 and 623 nm, ascribed to5D4→7FJ (J=6–3) transitions of Tb3+ ions. The latter was shown as a broad band peaked at about 450 nm. Alkali metal ions A+(A=Li, Na and K) were introduced asthe charge compensators to improve the lumines-cence of samples. The influence of charge compensators on the emissions of Tb3+ ions and oxygen defects OF? was investigated by the measurement of fluorescence spectra and luminescence decay curves. The results indicated that all the charge compensators weakened the defects emission. Furthermore, Li+ ion was the best charge compensator, because it not only reduced the defects emis-sion but also increased the emission intensity of Tb3+ significantly. Our results suggested that this nanophosphor sensitized by the charge compensator might broaden potential applications of rare-earth doped CaFCl.

  16. Alkali metal pool boiler life tests for a 25 kWe advanced Stirling conversion system

    Science.gov (United States)

    Anderson, W. G.; Rosenfeld, J. H.; Noble, J.

    The overall operating temperature and efficiency of solar-powered Stirling engines can be improved by adding an alkali metal pool boiler heat transport system to supply heat more uniformly to the heater head tubes. One issue with liquid metal pool boilers is unstable boiling. Stable boiling is obtained with an enhanced boiling surface containing nucleation sites that promote continuous boiling. Over longer time periods, it is possible that the boiling behavior of the system will change. An 800-h life test was conducted to verify that pool boiling with the chosen fluid/surface combination remains stable as the system ages. The apparatus uses NaK boiling on a - 100 + 140 stainless steel sintered porous layer, with the addition of a small amount of xenon. Pool boiling remained stable to the end of life test. The pool boiler life test included a total of 82 cold starts, to simulate startup each morning, and 60 warm restarts, to simulate cloud cover transients. The behavior of the cold and warm starts showed no significant changes during the life test. In the experiments, the fluid/surface combination provided stable, high-performance boiling at the operating temperature of 700 C. Based on these experiments, a pool boiler was designed for a full-scale 25-kWe Stirling system.

  17. Alkali metal cation doping of metal-organic framework for enhancing carbon dioxide adsorption capacity

    Institute of Scientific and Technical Information of China (English)

    Yan Cao; Yunxia Zhao; Fujiao Song; Qin Zhong

    2014-01-01

    Metal-organic frameworks (MOFs) have attracted much attention as adsorbents for the separation of CO2 from flue gas or natural gas. Here, a typical metal-organic framework HKUST-1(also named Cu-BTC or MOF-199) was chemically reduced by doping it with alkali metals (Li, Na and K) and they were further used to investigate their CO2 adsorption capacities. The structural information, surface chemistry and thermal behavior of the prepared adsorbent samples were characterized by X-ray powder diffraction (XRD), thermo-gravimetric analysis (TGA) and nitrogen adsorption-desorption isotherm analysis. The results showed that the CO2 storage capacity of HKUST-1 doped with moderate quantities of Li+, Na+ and K+, individually, was greater than that of unmodified HKUST-1. The highest CO2 adsorption uptake of 8.64 mmol/g was obtained with 1K-HKUST-1, and it was ca. 11%increase in adsorption capacity at 298 K and 18 bar as compared with HKUST-1. Moreover, adsorption tests showed that HKUST-1 and 1K-HKUST-1 displayed much higher adsorption capacities of CO2 than those of N2. Finally, the adsorption/desorption cycle experiment revealed that the adsorption performance of 1K-HKUST-1 was fairly stable, without obvious deterioration in the adsorption capacity of CO2 after 10 cycles.

  18. Alkali Metal Ion Complexes with Phosphates, Nucleotides, Amino Acids, and Related Ligands of Biological Relevance. Their Properties in Solution.

    Science.gov (United States)

    Crea, Francesco; De Stefano, Concetta; Foti, Claudia; Lando, Gabriele; Milea, Demetrio; Sammartano, Silvio

    2016-01-01

    Alkali metal ions play very important roles in all biological systems, some of them are essential for life. Their concentration depends on several physiological factors and is very variable. For example, sodium concentrations in human fluids vary from quite low (e.g., 8.2 mmol dm(-3) in mature maternal milk) to high values (0.14 mol dm(-3) in blood plasma). While many data on the concentration of Na(+) and K(+) in various fluids are available, the information on other alkali metal cations is scarce. Since many vital functions depend on the network of interactions occurring in various biofluids, this chapter reviews their complex formation with phosphates, nucleotides, amino acids, and related ligands of biological relevance. Literature data on this topic are quite rare if compared to other cations. Generally, the stability of alkali metal ion complexes of organic and inorganic ligands is rather low (usually log K  Na(+) > K(+) > Rb(+) > Cs(+). For example, for citrate it is: log K ML = 0.88, 0.80, 0.48, 0.38, and 0.13 at 25 °C and infinite dilution. Some considerations are made on the main aspects related to the difficulties in the determination of weak complexes. The importance of the alkali metal ion complexes was also studied in the light of modelling natural fluids and in the use of these cations as probes for different processes. Some empirical relationships are proposed for the dependence of the stability constants of Na(+) complexes on the ligand charge, as well as for correlations among log K values of NaL, KL or LiL species (L = generic ligand). PMID:26860301

  19. Research Investigation Directed Toward Extending the Useful Range of the Electromagnetic Spectrum. [atomic spectra and electronic structure of alkali metals

    Science.gov (United States)

    Hartmann, S. R.; Happer, W.

    1974-01-01

    The report discusses completed and proposed research in atomic and molecular physics conducted at the Columbia Radiation Laboratory from July 1972 to June 1973. Central topics described include the atomic spectra and electronic structure of alkali metals and helium, molecular microwave spectroscopy, the resonance physics of photon echoes in some solid state systems (including Raman echoes, superradiance, and two photon absorption), and liquid helium superfluidity.

  20. Structure of the Alkali-metal-atom-Strontium molecular ions: towards photoassociation and formation of cold molecular ions

    OpenAIRE

    Aymar, Mireille; Guérout, Romain; Dulieu, Olivier

    2011-01-01

    The potential energy curves, permanent and transition dipole moments, and the static dipolar polarizability, of molecular ions composed of one alkali-metal atom and a Strontium ion are determined with a quantum chemistry approach. The molecular ions are treated as effective two-electron systems and are treated using effective core potentials including core polarization, large gaussian basis sets, and full configuration interaction. In the perspective of upcoming experiments aiming at merging ...

  1. Efficient destruction of CF4 through in situ generation of alkali metals from heated alkali halide reducing mixtures.

    Science.gov (United States)

    Lee, Myung Churl; Choi, Wonyong

    2002-03-15

    Perfluorocarbons (PFCs) are the most potent green house gases that are very recalcitrant at destruction. An effective way of converting PFCs using hot solid reagents into safe products has been recently introduced. By investigating the thermal reductive destruction of tetrafluoromethane (CF4) we provided new insight and more physicochemical consideration on this novel process. The complete destruction of CF4was successfully achieved by flowing the gas through a heated reagent bed (400-950 degrees C) that contained powder mixtures of alkali halides, CaO, and Si. The silicon acted as a reducing agent of alkali halides for the in-situ production of alkali metals, and the calcium oxide played the role of a halide ion acceptor. The absence of any single component in this ternary mixture drastically reduced the destruction efficiency of CF4. The CF4 destruction efficiencies with the solid reagent containing the alkali halide, MX, increased in the order of Li approximately Na < K < Cs for alkali cations and I < Br < Cl < F for halide anions. This trend agreed with the endothermicity of the alkali metal generation reaction: the higher the endothermicity, the lower the destruction efficiency. Alkali metal generation was indirectly detected by monitoring H2 production from its reaction with water. The production of alkali metals increased with NaF, KF, and CsF in this order. The CsF/CaO/Si system exhibited the complete destruction of CF4 at as low as 600 degrees C. The solid product analysis by X-ray diffraction (XRD) showed the formation of CaF2 and the depletion of Si with black carbon particles formed in the solid reagent residue. No CO/CO2 and toxic HF and SiF4 formation were detected in the exhaust gas. PMID:11944694

  2. Optical detection of sodium salts of fluoride, acetate and phosphate by a diacylhydrazine ligand by the formation of a colour alkali metal complex

    Indian Academy of Sciences (India)

    Purnandhu Bose; Ranjan Dutta; I Ravikumar; Pradyut Ghosh

    2011-11-01

    A solution of N, N'-diacylhydrazine ligand in organic solvent is potential for colourimetric detection of F−/AcO−/PO$^{3−}_{4}$ via -NH deprotonation, tautomerization and its stabilization as a colour alkali metal complex.

  3. Nano-baskets of Calix[4]-1,3-crown in Emulsion Membranes for Selective Extraction of Alkali Metal Cations

    Institute of Scientific and Technical Information of China (English)

    Bahram Mokhtari; Kobra Pourabdollah

    2013-01-01

    Nano-assisted inclusion separation of alkali metals from basic solutions was reported by inclu-sion-facilitated emulsion liquid membrane process. The novelty of this study is application of nano-baskets of calixcrown in the selective and efficient separation of alkali metals as both the carrier and the surfactant. For this aim, four derivatives of diacid calix[4]-1,3-crowns-4,5 were synthesized, and their inclusion-extraction parameters were optimized including the calixcrown scaffold (4.4%, by mass) as the carrier/demulsifier, the commercial kero-sene as diluent in membrane, sulphonic acid (0.2 mol·L-1) and ammonium carbonate (0.4 mol·L-1) as the strip and the feed phases, the phase and the treat ratios of 0.8 and 0.3, mixing speed (300 r·min-1), and initial solute concen-tration (100 mg·L-1). The selectivity of membrane over more than ten interfering cations was examined and the re-sults reveled that under the optimized operating condition, the degree of inclusion-extraction of alkali metals was as high as 98%-99%.

  4. Properties of alkali metal atoms deposited on a MgO surface: a systematic experimental and theoretical study.

    Science.gov (United States)

    Finazzi, Emanuele; Di Valentin, Cristiana; Pacchioni, Gianfranco; Chiesa, Mario; Giamello, Elio; Gao, Hongjun; Lian, Jichun; Risse, Thomas; Freund, Hans-Joachim

    2008-01-01

    The adsorption of small amounts of alkali metal atoms (Li, Na, K, Rb, and Cs) on the surface of MgO powders and thin films has been studied by means of EPR spectroscopy and DFT calculations. From a comparison of the measured and computed g values and hyperfine coupling constants (hfccs), a tentative assignment of the preferred adsorption sites is proposed. All atoms bind preferentially to surface oxide anions, but the location of these anions differs as a function of the deposition temperature and alkali metal. Lithium forms relatively strong bonds with MgO and can be stabilized at low temperatures on terrace sites. Potassium interacts very weakly with MgO and is stabilized only at specific sites, such as at reverse corners where it can interact simultaneously with three surface oxygen atoms (rubidium and cesium presumably behave in the same way). Sodium forms bonds of intermediate strength and could, in principle, populate more than a single site when deposited at room temperature. In all cases, large deviations of the hfccs from the gas-phase values are observed. These reductions in the hfccs are due to polarization effects and are not connected to ionization of the alkali metal, which would lead to the formation of an adsorbed cation and a trapped electron. In this respect, hydrogen atoms behave completely differently. Under similar conditions, they form (H(+))(e(-)) pairs. The reasons for this different behavior are discussed. PMID:18381711

  5. Development of an optically pumped atomic magnetometer using a K-Rb hybrid cell and its application to magnetocardiography

    Directory of Open Access Journals (Sweden)

    Yosuke Ito

    2012-09-01

    Full Text Available We have developed an optically pumped atomic magnetometer using a hybrid cell of K and Rb. The hybrid optical pumping technique can apply dense alkali-metal vapor to the sensor head and leads to high signal intensity. We use dense Rb vapor as probed atoms, and achieve a sensitivity of approximately 100 fTrms/Hz1/2 around 10 Hz. In this case, the sensitivity is limited by the system noise, and the magnetic linewidth is narrower than that for direct Rb optical pumping. We demonstrated magnetocardiography using the magnetometer and obtained clear human magnetocardiograms.

  6. Are endothelial cell bioeffects from acoustic droplet vaporization proximity dependent?

    Science.gov (United States)

    Seda, Robinson; Li, David; Fowlkes, J. Brian; Bull, Joseph

    2013-11-01

    Acoustic droplet vaporization (ADV) produces gas microbubbles that provide a means of selective occlusion in gas embolotherapy. Vaporization and subsequent occlusion occur inside blood vessels supplying the targeted tissue, such as tumors. Theoretical and computational studies showed that ADV within a vessel can impart high fluid mechanical stresses on the vessel wall. Previous in vitro studies have demonstrated that vaporization at an endothelial layer may affect cell attachment and viability. The current study is aimed at investigating the role of vaporization distance away from the endothelial layer. HUVECs were cultured in OptiCell™ chambers until reaching confluence. Dodecafluoropentane microdroplets were added, attaining a 10:1 droplet to cell ratio. A single ultrasound pulse (7.5 MHz) consisting of 16 cycles (~ 2 μs) and a 5 MPa peak rarefactional pressure was used to produce ADV while varying the vaporization distance from the endothelial layer (0 μm, 500 μm, 1000 μm). Results indicated that cell attachment and viability was significantly different if the distance was 0 μm (at the endothelial layer). Other distances were not significantly different from the control. ADV will significantly affect the endothelium if droplets are in direct contact with the cells. Droplet concentration and flow conditions inside blood vessels may play an important role. This work was supported by NIH grant R01EB006476.

  7. UV and IR spectroscopy of cold 1,2-dimethoxybenzene complexes with alkali metal ions.

    Science.gov (United States)

    Inokuchi, Yoshiya; Boyarkin, Oleg V; Ebata, Takayuki; Rizzo, Thomas R

    2012-04-01

    We report UV photodissociation (UVPD) and IR-UV double-resonance spectra of 1,2-dimethoxybenzene (DMB) complexes with alkali metal ions, M(+)·DMB (M = Li, Na, K, Rb, and Cs), in a cold, 22-pole ion trap. The UVPD spectrum of the Li(+) complex shows a strong origin band. For the K(+)·DMB, Rb(+)·DMB, and Cs(+)·DMB complexes, the origin band is very weak and low-frequency progressions are much more extensive than that of the Li(+) ion. In the case of the Na(+)·DMB complex, spectral features are similar to those of the K(+), Rb(+), and Cs(+) complexes, but vibronic bands are not resolved. Geometry optimization with density functional theory indicates that the metal ions are bonded to the oxygen atoms in all the M(+)·DMB complexes. For the Li(+) complex in the S(0) state, the Li(+) ion is located in the same plane as the benzene ring, while the Na(+), K(+), Rb(+), and Cs(+) ions are located off the plane. In the S(1) state, the Li(+) complex has a structure similar to that in the S(0) state, providing the strong origin band in the UV spectrum. In contrast, the other complexes show a large structural change in the out-of-plane direction upon S(1)-S(0) excitation, which results in the extensive low-frequency progressions in the UVPD spectra. For the Na(+)·DMB complex, fast charge transfer occurs from Na(+) to DMB after the UV excitation, making the bandwidth of the UVPD spectrum much broader than that of the other complexes and producing the photofragment DMB(+) ion.

  8. Study on the Characteristics of an Alkali-Metal Thermoelectric Power Generation System

    Science.gov (United States)

    Lee, Wook-Hyun; Hwang, Hyun-Chang; Lee, Ji-Su; Kim, Pan-Jo; Lim, Sang-Hyuk; Rhi, Seok-Ho; Lee, Kye-Bock; Lee, Ki-Woo

    2015-10-01

    In the present study, a numerical simulation and experimental studies of an alkali-metal thermoelectric energy converter (AMTEC) system were carried out. The present, unique AMTEC model consists of an evaporator, a β-alumina solid electrolyte (BASE) tube, a condenser, and an artery cable wick. The key points for operation of the present AMTEC were 1100 K in the evaporator and 600 K in the condenser. A numerical model based on sodium-saturated porous wicks was developed and shown to be able to simulate the AMTEC system. The simulation results show that the AMTEC system can generate up to 100 W with a given design. The AMTEC system developed in the present work and used in the practical investigations could generate an electromotive force of 7 V. Artery wick and evaporator wick structures were simulated for the optimum design. Both sodium-saturated wicks were affected by numerous variables, such as the input heat power, cooling temperature, sodium mass flow rate, and capillary-driven fluid flow. Based on an effective thermal conductivity model, the presented simulation could successfully predict the system performance. Based on the numerical simulation, the AMTEC system operates with efficiency near 10% to 15%. In the case of an improved BASE design, the system could reach efficiency of over 30%. The system was designed for 0.6 V power, 25 A current, and 100 W power input. In addition, in this study, the temperature effects in each part of the AMTEC system were analyzed using a heat transfer model in porous media to apply to the computational fluid dynamics at a predetermined temperature condition for the design of a 100-W AMTEC prototype. It was found that a current density of 0.5 A/cm2 to 0.9 A/cm2 for the BASE is suitable when the temperatures of the evaporator section and condenser section are 1100 K and 600 K, respectively.

  9. N-alkyl pyrrolidone ether podands as versatile alkali metal ion chelants.

    Science.gov (United States)

    Perrin, Andrea; Myers, Dominic; Fucke, Katharina; Musa, Osama M; Steed, Jonathan W

    2014-02-28

    This work explores the coordination chemistry of a bis(pyrrolidone) ether ligand. Pyrrolidones are commercially important functional groups because of the high polarity and hence high hydrophilicity and surface affinity. An array of alkali metal ion complexes of a podand bearing two pendant pyrrolidone functionalities, namely 1-{2-[2-(2-oxo-pyrrolid-1-yl)-ethoxy]-ethyl}-pyrrolid-2-one (1) are reported. Reaction of this ligand with sodium hexafluorophosphate gives two discrete species of formulae [Na(1)2]PF6 (3) and [Na3(H2O)2(μ-1)2](PF6)3 (4), and a coordination polymer {[Na3(μ3-1)3(μ2-1)](PF6)3}n (5). The same reaction in methanol gives a 1 : 1 complex, namely [Na2(μ-1)2(MeOH)2](PF6)2 (6). Use of tetraphenyl borate as a less coordinating counter ion gives [Na2(1)2(H2O)4](BPh4)2 (7) and [Na2(1)4](BPh4)2 (8). Two potassium complexes have also been isolated, a monomer [K(1)2]PF6 (9) and a cyclic tetramer [K4(μ4-H2O)2(μ-1)4](PF6)4 (10). The structures illustrate the highly polar nature of the amide carbonyl moiety within bis(pyrrolidone) ethers with longer interactions to the ether oxygen atom. The zinc complex is also reported and {[ZnCl2(μ-1)]}n (11) exhibits bonding only to the carbonyl moieties. The ether oxygen atom is not necessary for Na(+) complexation as exemplified by the structure of the sodium complex of the analogue 1,3-bis(pyrrolid-2-on-1-yl)butane (2). Reaction of compound 1 with lithium salts results in isolation of the protonated ligand. PMID:24336897

  10. Design and Test of Advanced Thermal Simulators for an Alkali Metal-Cooled Reactor Simulator

    Science.gov (United States)

    Garber, Anne E.; Dickens, Ricky E.

    2011-01-01

    The Early Flight Fission Test Facility (EFF-TF) at NASA Marshall Space Flight Center (MSFC) has as one of its primary missions the development and testing of fission reactor simulators for space applications. A key component in these simulated reactors is the thermal simulator, designed to closely mimic the form and function of a nuclear fuel pin using electric heating. Continuing effort has been made to design simple, robust, inexpensive thermal simulators that closely match the steady-state and transient performance of a nuclear fuel pin. A series of these simulators have been designed, developed, fabricated and tested individually and in a number of simulated reactor systems at the EFF-TF. The purpose of the thermal simulators developed under the Fission Surface Power (FSP) task is to ensure that non-nuclear testing can be performed at sufficiently high fidelity to allow a cost-effective qualification and acceptance strategy to be used. Prototype thermal simulator design is founded on the baseline Fission Surface Power reactor design. Recent efforts have been focused on the design, fabrication and test of a prototype thermal simulator appropriate for use in the Technology Demonstration Unit (TDU). While designing the thermal simulators described in this paper, effort were made to improve the axial power profile matching of the thermal simulators. Simultaneously, a search was conducted for graphite materials with higher resistivities than had been employed in the past. The combination of these two efforts resulted in the creation of thermal simulators with power capacities of 2300-3300 W per unit. Six of these elements were installed in a simulated core and tested in the alkali metal-cooled Fission Surface Power Primary Test Circuit (FSP-PTC) at a variety of liquid metal flow rates and temperatures. This paper documents the design of the thermal simulators, test program, and test results.

  11. Alkali-Metal-Ion-Functionalized Graphene Oxide as a Superior Anode Material for Sodium-Ion Batteries.

    Science.gov (United States)

    Wan, Fang; Li, Yu-Han; Liu, Dai-Huo; Guo, Jin-Zhi; Sun, Hai-Zhu; Zhang, Jing-Ping; Wu, Xing-Long

    2016-06-01

    Although graphene oxide (GO) has large interlayer spacing, it is still inappropriate to use it as an anode for sodium-ion batteries (SIBs) because of the existence of H-bonding between the layers and ultralow electrical conductivity which impedes the Na(+) and e(-) transformation. To solve these issues, chemical, thermal, and electrochemical procedures are traditionally employed to reduce GO nanosheets. However, these strategies are still unscalable, consume high amounts of energy, and are expensive for practical application. Here, for the first time, we describe the superior Na storage of unreduced GO by a simple and scalable alkali-metal-ion (Li(+) , Na(+) , K(+) )-functionalized process. The various alkali metals ions, connecting with the oxygen on GO, have played different effects on morphology, porosity, degree of disorder, and electrical conductivity, which are crucial for Na-storage capabilities. Electrochemical tests demonstrated that sodium-ion-functionalized GO (GNa) has shown outstanding Na-storage performance in terms of excellent rate capability and long-term cycle life (110 mAh g(-1) after 600 cycles at 1 A g(-1) ) owing to its high BET area, appropriate mesopore, high degree of disorder, and improved electrical conductivity. Theoretical calculations were performed using the generalized gradient approximation (GGA) to further study the Na-storage capabilities of functionalized GO. These calculations have indicated that the Na-O bond has the lowest binding energy, which is beneficial to insertion/extraction of the sodium ion, hence the GNa has shown the best Na-storage properties among all comparatives functionalized by other alkali metal ions. PMID:27136376

  12. Methane coupling reaction in an oxy-steam stream through an OH radical pathway by using supported alkali metal catalysts

    KAUST Repository

    Liang, Yin

    2014-03-24

    A universal reaction mechanism involved in the oxidative coupling of methane (OCM) is demonstrated under oxy-steam conditions using alkali-metal-based catalysts. Rigorous kinetic measurements indicated a reaction mechanism that is consistent with OH radical formation from a H 2O-O2 reaction followed by C-H activation in CH 4 with an OH radical. Thus, the presence of water enhances both the CH4 conversion rate and the C2 selectivity. This OH radical pathway that is selective for the OCM was observed for the catalyst without Mn, which suggests clearly that Mn is not the essential component in a selective OCM catalyst. The experiments with different catalyst compositions revealed that the OH.-mediated pathway proceeded in the presence of catalysts with different alkali metals (Na, K) and different oxo anions (W, Mo). This difference in catalytic activity for OH radical generation accounts for the different OCM selectivities. As a result, a high C2 yield is achievable by using Na2WO4/SiO2, which catalyzes the OH.-mediated pathway selectively. Make it methane: A universal reaction mechanism involved in the oxidative coupling of methane is demonstrated under oxy-stream conditions by using alkali-metal-based catalysts. Rigorous kinetic measurements indicated a reaction mechanism that is consistent with OH radical formation from an H2O-O2 reaction, followed by C-H activation in CH4 with an OH radical. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Tandem mass spectrometric study of ciprofloxacin-poly(ethylene glycol) conjugate in the presence of alkali metal ions

    Science.gov (United States)

    Kéki, Sándor; Nagy, Lajos; Kuki, Ákos; Pintér, Gábor; Herczegh, Pál; Zsuga, Miklós

    2008-08-01

    The fragmentation and fragmentation behaviors of singly, doubly, and triply charged adducts of ciprofloxacin-poly(ethylene glycol) conjugate (P_Cf) with alkali metal ions, including Li+, Na+ and K+ ions, generated by electrospray (ESI) were studied as a function of collision energy. The product ion spectra of adducts with charge states +1, +2, and +3 are dominated by product ions arising from the loss-neutral moiety (ciprofloxacin) and CO2, and ions formed by dissociation of the precursor ion ([P_Cf + xM]x+) into product ions [P + (x - 1)M](x-1)+ and [Cf + M]+ (where P_Cf, P and Cf represent the ciprofloxacin-poly(ethylene glycol) conjugate, the poly(ethylene glycol) backbone without the endgroups, and the ciprofloxacin moiety, respectively; M is the alkali metal ion and x is the charge). It was found that the metal ions do not significantly alter the fragmentation pattern of ciprofloxacin-poly(ethylene glycol) conjugate. It is also interesting that the run and the shape of the survival yield curves for the singly and doubly charged adduct ions are independent of the cation. However, in the case of triply charged adducts, survival yield curves follow each other in the order K+, Na+, and Li+. Based on the experimental results, a fragmentation mechanism for the singly and multiply charged adducts of P_Cf with alkali metal ions is given. In addition, a tentative description of the signal intensity variations of the product ions with the lab frame collision energy is also reported.

  14. New class of scorpionate: tris(tetrazolyl)-iron complex and its different coordination modes for alkali metal ions.

    Science.gov (United States)

    Park, Ka Hyun; Lee, Kang Mun; Go, Min Jeong; Choi, Sung Ho; Park, Hyoung-Ryun; Kim, Youngjo; Lee, Junseong

    2014-08-18

    We report formation of a new metallascorpionate ligand, [FeL3](3-) (IPtz), containing a Fe core and three 5-(2-hydroxyphenyl)-1H-tetrazole (LH2) ligands. It features two different binding sites, oxygen and nitrogen triangles, which consist of three oxygen or nitrogen donors from tetrazole. The binding affinities of the complex for three alkali metal ions were studied using UV spectrophotometry titrations. All three alkali metal ions show high affinities and binding constants (>3 × 10(6) M(-1)), based on the 1:1 binding isotherms to IPtz. The coordination modes of the alkali metals and IPtz in the solid were studied using X-ray crystallography; two different electron-donor sites show different coordination numbers for Li(+), Na(+), and K(+) ions. The oxygen triangles have the κ(2) coordination mode with Li(+) and κ(3) coordination mode with Na(+) and K(+) ions, whereas the nitrogen triangles show κ(3) coordination with K(+) only. The different binding affinities of IPtz in the solid were manipulated using multiple metal precursors. A Fe-K-Zn trimetallic complex was constructed by assembly of an IPtz ligand, K, and Zn precursors and characterized using X-ray crystallography. Oxygen donors are coordinated with the K ion via the κ(3) coordination mode, and nitrogen donors are coordinated with Zn metal by κ(3) coordination. The solid-state structure was confirmed to be a honeycomb coordination polymer with a one-dimensional infinite metallic array, i.e., -(K-K-Fe-Zn-Fe-K)n-.

  15. Crown-Ether Derived Graphene Hybrid Composite for Membrane-Free Potentiometric Sensing of Alkali Metal Ions

    DEFF Research Database (Denmark)

    Olsen, Gunnar; Ulstrup, Jens; Chi, Qijin

    2016-01-01

    surface coverage is achieved by the introduction of a flexible linking molecule. The resulting hybrid composite is highly stable and is capable of detecting potassium ions down to micromolar ranges with a selectivity over other cations (including Ca2+, Li+, Na+, NH4+) at concentrations up to 25 m......We report the design and synthesis of newly functionalized graphene hybrid material that can be used for selective membrane-free potentiometric detection of alkali metal ions, represented by potassium ions. Reduced graphene oxide (RGO) functionalized covalently by 18-crown[6] ether with a dense...

  16. Sensitive determination of the spin polarization of optically pumped alkali-metal atoms using near-resonant light.

    Science.gov (United States)

    Ding, Zhichao; Long, Xingwu; Yuan, Jie; Fan, Zhenfang; Luo, Hui

    2016-01-01

    A new method to measure the spin polarization of optically pumped alkali-metal atoms is demonstrated. Unlike the conventional method using far-detuned probe light, the near-resonant light with two specific frequencies was chosen. Because the Faraday rotation angle of this approach can be two orders of magnitude greater than that with the conventional method, this approach is more sensitive to the spin polarization. Based on the results of the experimental scheme, the spin polarization measurements are found to be in good agreement with the theoretical predictions, thereby demonstrating the feasibility of this approach. PMID:27595707

  17. Thermophysical properties of alkali metal vapours. Part II - assessment of experimental data on thermal conductivity and viscosity

    OpenAIRE

    Fialho, Paulo; Ramires, Maria de Lurdes V.; Nieto de Castro, Carlos A.; João M. N. A. Fareleira; Mardolcar, Umesh V.

    1994-01-01

    Copyright © 1994 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Article first published online: 8 MAY 2010. An analysis of the available data on the viscosity and thermal conductivity coefficients of the alkali metal vapours is presented. The analysis is based upon theoretical calculations of the properties of the monatomic systems, described in the preceding parts I and I.A of the present paper, and making use of the kinetic theory of a binary gas reacting mixture. A summary of the measur...

  18. Metal-mediated aminocatalysis provides mild conditions: Enantioselective Michael addition mediated by primary amino catalysts and alkali-metal ions

    Directory of Open Access Journals (Sweden)

    Matthias Leven

    2013-01-01

    Full Text Available Four catalysts based on new amides of chiral 1,2-diamines and 2-sulfobenzoic acid have been developed. The alkali-metal salts of these betaine-like amides are able to form imines with enones, which are activated by Lewis acid interaction for nucleophilic attack by 4-hydroxycoumarin. The addition of 4-hydroxycoumarin to enones gives ee’s up to 83% and almost quantitative yields in many cases. This novel type of catalysis provides an effective alternative to conventional primary amino catalysis were strong acid additives are essential components.

  19. Solid State Structures of Alkali Metal Ion Complexes Formed by Low-Molecular-Weight Ligands of Biological Relevance.

    Science.gov (United States)

    Aoki, Katsuyuki; Murayama, Kazutaka; Hu, Ning-Hai

    2016-01-01

    This chapter provides structural data, mainly metal binding sites/modes, observed in crystal structures of alkali metal ion complexes containing low-molecular-weight ligands of biological relevance, mostly obtained from the Cambridge Structural Database (the CSD version 5.35 updated to February 2014). These ligands include (i) amino acids and small peptides, (ii) nucleic acid constituents (excluding quadruplexes and other oligonucleotides), (iii) simple carbohydrates, and (iv) naturally occurring antibiotic ionophores. For some representative complexes of these ligands, some details on the environment of the metal coordination and structural characteristics are described. PMID:26860299

  20. Cooper minima in the transitions from low-excited and Rydberg states of alkali-metal atoms

    OpenAIRE

    Beterov, I. I.; Mansell, C. W.; Yakshina, E. A.; Ryabtsev, I. I.; Tretyakov, D. B.; Entin, V. M.; MacCormick, C.; Piotrowicz, M. J.; Kowalczyk, A.; S. Bergamini

    2012-01-01

    The structure of the Cooper minima in the transition probabilities and photoionization cross-sections for low-excited and Rydberg nS, nP, nD and nF states of alkali-metal atoms has been studied using a Coulomb approximation and a quasiclassical model. The range of applicability of the quasiclassical model has been defined from comparison with available experimental and theoretical data on dipole moments, oscillator strengths, and photoionization cross-sections. A new Cooper minimum for transi...

  1. Cooper minima in the transitions from low-excited and Rydberg states of alkali-metal atoms

    CERN Document Server

    Beterov, I I; Yakshina, E A; Ryabtsev, I I; Tretyakov, D B; Entin, V M; MacCormick, C; Piotrowicz, M J; Kowalczyk, A; Bergamini, S

    2012-01-01

    The structure of the Cooper minima in the transition probabilities and photoionization cross-sections for low-excited and Rydberg nS, nP, nD and nF states of alkali-metal atoms has been studied using a Coulomb approximation and a quasiclassical model. The range of applicability of the quasiclassical model has been defined from comparison with available experimental and theoretical data on dipole moments, oscillator strengths, and photoionization cross-sections. A new Cooper minimum for transitions between rubidium Rydberg states has been found.

  2. Elimination technique for alkali metal ion adducts from an electrospray ionization process using an on-line ion suppressor

    OpenAIRE

    NOZAKI, Kazuyoshi; TARUI, Akira; OSAKA, Issey; Kawasaki, Hideya; ARAKAWA, Ryuichi; 荒川, 隆一

    2010-01-01

    The effects of an on-line ion suppressor device on alkali metal ion adduct formations of the model compound tacrolimus were investigated. The base peak ion in the positive ion ESI-MS spectrum of tacrolimus was a sodium ion adduct, [M+Na]+. On the other hand, an ammonium ion adduct, [M+NH4]+, was the base peak ion in the full-scan mass spectrum of tacrolimus with a cation-exchange suppressor resin, and both [M+Na]+ and [M+K]+ were eliminated. These results indicate that the combination of an o...

  3. Slow light in paraffin-coated Rb vapor cells

    CERN Document Server

    Klein, M; Phillips, D F; Walsworth, R L

    2006-01-01

    We present preliminary results from an experimental study of slow light in anti-relaxation-coated Rb vapor cells, and describe the construction and testing of such cells. The slow ground state decoherence rate allowed by coated cell walls leads to a dual-structured electromagnetically induced transparency (EIT) spectrum with a very narrow (<100 Hz) transparency peak on top of a broad pedestal. Such dual-structure EIT permits optical probe pulses to propagate with greatly reduced group velocity on two time scales. We discuss ongoing efforts to optimize the pulse delay in such coated cell systems.

  4. Molecular origin of high free energy barriers for alkali metal ion transfer through ionic liquid-graphene electrode interfaces.

    Science.gov (United States)

    Ivaništšev, Vladislav; Méndez-Morales, Trinidad; Lynden-Bell, Ruth M; Cabeza, Oscar; Gallego, Luis J; Varela, Luis M; Fedorov, Maxim V

    2016-01-14

    In this work we study mechanisms of solvent-mediated ion interactions with charged surfaces in ionic liquids by molecular dynamics simulations, in an attempt to reveal the main trends that determine ion-electrode interactions in ionic liquids. We compare the interfacial behaviour of Li(+) and K(+) at a charged graphene sheet in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, and its mixtures with lithium and potassium tetrafluoroborate salts. Our results show that there are dense interfacial solvation structures in these electrolytes that lead to the formation of high free energy barriers for these alkali metal cations between the bulk and direct contact with the negatively charged surface. We show that the stronger solvation of Li(+) in the ionic liquid leads to the formation of significantly higher interfacial free energy barriers for Li(+) than for K(+). The high free energy barriers observed in our simulations can explain the generally high interfacial resistance in electrochemical storage devices that use ionic liquid-based electrolytes. Overcoming these barriers is the rate-limiting step in the interfacial transport of alkali metal ions and, hence, appears to be a major drawback for a generalised application of ionic liquids in electrochemistry. Some plausible strategies for future theoretical and experimental work for tuning them are suggested.

  5. Molecular origin of high free energy barriers for alkali metal ion transfer through ionic liquid-graphene electrode interfaces.

    Science.gov (United States)

    Ivaništšev, Vladislav; Méndez-Morales, Trinidad; Lynden-Bell, Ruth M; Cabeza, Oscar; Gallego, Luis J; Varela, Luis M; Fedorov, Maxim V

    2016-01-14

    In this work we study mechanisms of solvent-mediated ion interactions with charged surfaces in ionic liquids by molecular dynamics simulations, in an attempt to reveal the main trends that determine ion-electrode interactions in ionic liquids. We compare the interfacial behaviour of Li(+) and K(+) at a charged graphene sheet in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, and its mixtures with lithium and potassium tetrafluoroborate salts. Our results show that there are dense interfacial solvation structures in these electrolytes that lead to the formation of high free energy barriers for these alkali metal cations between the bulk and direct contact with the negatively charged surface. We show that the stronger solvation of Li(+) in the ionic liquid leads to the formation of significantly higher interfacial free energy barriers for Li(+) than for K(+). The high free energy barriers observed in our simulations can explain the generally high interfacial resistance in electrochemical storage devices that use ionic liquid-based electrolytes. Overcoming these barriers is the rate-limiting step in the interfacial transport of alkali metal ions and, hence, appears to be a major drawback for a generalised application of ionic liquids in electrochemistry. Some plausible strategies for future theoretical and experimental work for tuning them are suggested. PMID:26661060

  6. Distribution and uptake of {sup 137}Cs in relation to alkali metals in a perhumid montane forest ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Chao, J.H. [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu 30013, Taiwan (China)], E-mail: jhchao@mx.nthu.edu.tw; Chiu, C.Y. [Research Center for Biodiversity, Academia Sinica, Taipei 11529, Taiwan (China); Lee, H.P. [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2008-10-15

    We determined the content of radiocesium ({sup 137}Cs) and alkali metals in soils, plants (2 ferns, a shrub and moss) and rainwater collected in an undisturbed forest ecosystem. The {sup 137}Cs activity and the isotopic ratio of {sup 137}Cs/Cs in the samples were used to interpret the distribution and uptake of {sup 137}Cs and the alkali metals in plants. As a whole, the {sup 137}Cs in plants was assimilated together with K but was not dependent on Cs. Different adaptations of fern species collected in ecological niches cause them to have different {sup 137}Cs/Cs ratios. Diplopterygium glaucum is distributed at the edges of the forest; it usually has shallow organic layers, and the root takes up more stable Cs from mineral layers, leading to lower {sup 137}Cs/Cs ratios than that in the understory Plagiogyria formosana and Rhododendron formosanum species. The steady supply of stable Cs through the uptake by D. glaucum from deep soils may gradually dilute the {sup 137}Cs concentration and thus explain the lower {sup 137}Cs/Cs ratio in the fern samples. The {sup 137}Cs is predicted to be proportional to the Cs content across plant species in the biological cycle once isotopic equilibrium is attained.

  7. Influence of alkali metal cations on the thermal, mechanical and morphological properties of rectorite/chitosan bio-nanocomposite films.

    Science.gov (United States)

    Babul Reddy, A; Jayaramudu, J; Siva Mohan Reddy, G; Manjula, B; Sadiku, E R

    2015-05-20

    The main theme of this work is to study the influence of ion-exchangeable alkali metal cations, such as: Li(+), Na(+), K(+), and Cs(+) on the thermal, mechanical and morphological properties. In this regard, a set of rectorite/chitosan (REC-CS) bio-nanocomposite films (BNCFs) was prepared by facile reaction of chitosan with ion-exchanged REC clay. The microstructure and morphology of BNCFs were investigated with XRD, TEM, SEM and AFM. Thermal and tensile properties of BNCFs were also investigated. As revealed from TEM and XRD results, the BNCFs featured a mixed morphology. Some intercalated clay sheets, together with nano-sized clay tactoids were obtained in LiREC/CS, NaREC/CS and KREC/CS of the BNCFs. From fractured surface study, via SEM, it was observed that the dispersion of chitosan polymer attaches to (and covers) the clay platelets. FTIR confirmed strong hydrogen bonds between clay and chitosan polymer. In addition, the thermal stabilities significantly varied when alkali metal cations varied from Li(+) to Cs(+). The BNCFs featured high tensile strengths (up to 84 MPa) and tensile moduli (up to 45 GPa). After evaluating these properties of BNCFs, we came to conclusion that these bio-nano composites can be used for packaging applications.

  8. Radio-frequency-modulated Rydberg states in a vapor cell

    CERN Document Server

    Miller, Stephanie A; Raithel, Georg

    2016-01-01

    We measure strong radio-frequency (RF) electric fields using rubidium Rydberg atoms prepared in a room-temperature vapor cell as field sensors. Electromagnetically induced transparency is employed as an optical readout. We RF-modulate the 60$S_{1/2}$ and 58$D_{5/2}$ Rydberg states with 50~MHz and 100~MHz fields, respectively. For weak to moderate RF fields, the Rydberg levels become Stark-shifted, and sidebands appear at even multiples of the driving frequency. In high fields, the adjacent hydrogenic manifold begins to intersect the shifted levels, providing rich spectroscopic structure suitable for precision field measurements. A quantitative description of strong-field level modulation and mixing of $S$ and $D$ states with hydrogenic states is provided by Floquet theory. Additionally, we estimate the shielding of DC electric fields in the interior of the glass vapor cell.

  9. Observation of light dragging in rubidium vapor cell

    CERN Document Server

    Strekalov, D V; Yu, N; Maleki, L; Strekalov, Dmitry; Matsko, Andrey B.; Yu, Nan; Maleki, Lute

    2003-01-01

    We report on the experimental demonstration of light dragging effect due to atomic motion in a rubidium vapor cell. We found that the minimum group velocity is achieved for light red-shifted from the center of the atomic resonance, and that the value of this shift increases with decreasing group velocity, in agreement with the theoretical predictions by Kocharovskaya, Rostovtsev, and Scully [Phys. Rev. Lett. {\\bf 86}, 628 (2001)].

  10. High resolution field imaging with atomic vapor cells

    OpenAIRE

    Horsley, Andrew

    2015-01-01

    In this thesis, I report on the development of imaging techniques in atomic vapor cells. This is a relatively unexplored area, despite the ubiquitous use of imaging in experiments with ultracold atoms. Our main focus is in high resolution imaging of microwave near fields, for which there is currently no satisfactory established technique. We detect microwave fields through Rabi oscillations driven by the microwave on atomic hyperfine transitions. The technique can be easily modified to also i...

  11. Structural and electronic engineering of 3DOM WO3 by alkali metal doping for improved NO2 sensing performance

    Science.gov (United States)

    Wang, Zhihua; Fan, Xiaoxiao; Han, Dongmei; Gu, Fubo

    2016-05-01

    Novel alkali metal doped 3DOM WO3 materials were prepared using a simple colloidal crystal template method. Raman, XRD, SEM, TEM, XPS, PL, Hall and UV-Vis techniques were used to characterize the structural and electronic properties of all the products, while the corresponding sensing performances targeting ppb level NO2 were determined at different working temperatures. For the overall goal of structural and electronic engineering, the co-effect of structural and electronic properties on the improved NO2 sensing performance of alkali metal doped 3DOM WO3 was studied. The test results showed that the gas sensing properties of 3DOM WO3/Li improved the most, with the fast response-recovery time and excellent selectivity. More importantly, the response of 3DOM WO3/Li to 500 ppb NO2 was up to 55 at room temperature (25 °C). The especially high response to ppb level NO2 at room temperature (25 °C) in this work has a very important practical significance. The best sensing performance of 3DOM WO3/Li could be ascribed to the most structure defects and the highest carrier mobility. And the possible gas sensing mechanism based on the model of the depletion layer was proposed to demonstrate that both structural and electronic properties are responsible for the NO2 sensing behavior.Novel alkali metal doped 3DOM WO3 materials were prepared using a simple colloidal crystal template method. Raman, XRD, SEM, TEM, XPS, PL, Hall and UV-Vis techniques were used to characterize the structural and electronic properties of all the products, while the corresponding sensing performances targeting ppb level NO2 were determined at different working temperatures. For the overall goal of structural and electronic engineering, the co-effect of structural and electronic properties on the improved NO2 sensing performance of alkali metal doped 3DOM WO3 was studied. The test results showed that the gas sensing properties of 3DOM WO3/Li improved the most, with the fast response-recovery time and

  12. Third order nonlinear optical properties and optical limiting behavior of alkali metal complexes of p-nitrophenol

    Science.gov (United States)

    Thangaraj, M.; Vinitha, G.; Sabari Girisun, T. C.; Anandan, P.; Ravi, G.

    2015-10-01

    Optical nonlinearity of metal complexes of p-nitrophenolate (M=Li, Na and K) in ethanol is studied by using a continuous wave (cw) diode pumped Nd:YAG laser (532 nm, 50 mW). The predominant mechanism of observed nonlinearity is thermal in origin. The nonlinear refractive index and the nonlinear absorption coefficient of the samples were found to be in the order of 10-8 cm2/W and 10-3 cm/W respectively. Magnitude of third-order optical parameters varies according to the choice of alkali metal chosen for metal complex formation of p-nitrophenolate. The third-order nonlinear susceptibility was found to be in the order of 10-6 esu. The observed saturable absorption and the self-defocusing effect were used to demonstrate the optical limiting action at 532 nm by using the same cw laser beam.

  13. A stochastic optimization method based technique for finding out reaction paths in noble gas clusters perturbed by alkali metal ions

    International Nuclear Information System (INIS)

    Graphical abstract: The structure of a minimum in Ar19K+ cluster. Abstract: In this paper we explore the possibility of using stochastic optimizers, namely simulated annealing (SA) in locating critical points (global minima, local minima and first order saddle points) in Argon noble gas clusters perturbed by alkali metal ions namely sodium and potassium. The atomic interaction potential is the Lennard Jones potential. We also try to see if a continuous transformation in geometry during the search process can lead to a realization of a kind of minimum energy path (MEP) for transformation from one minimum geometry to another through a transition state (first order saddle point). We try our recipe for three sizes of clusters, namely (Ar)16M+, (Ar)19M+ and (Ar)24M+, where M+ is Na+ and K+.

  14. Alkali metal salts of rutin - Synthesis, spectroscopic (FT-IR, FT-Raman, UV-VIS), antioxidant and antimicrobial studies.

    Science.gov (United States)

    Samsonowicz, M; Kamińska, I; Kalinowska, M; Lewandowski, W

    2015-12-01

    In this work several metal salts of rutin with lithium, sodium, potassium, rubidium and cesium were synthesized. Their molecular structures were discussed on the basis of spectroscopic (FT-IR, FT-Raman, UV-VIS) studies. Optimized geometrical structure of rutin was calculated by B3LYP/6-311++G(∗∗) method and sodium salt of rutin were calculated by B3LYP/LanL2DZ method. Metal chelation change the biological properties of ligand therefore the antioxidant (FRAP and DPPH) and antimicrobial activities (toward Escherichia coli, Staphylococcus aureus, Enterococcus faecium, Proteus vulgaris, Pseudomonas aeruginosa, Klebsiella pneumonia, Candida albicans and Saccharomyces cerevisiae) of alkali metal salts were evaluated and compared with the biological properties of rutin. PMID:26184478

  15. Synthesis and X-ray Characterization of Alkali Metal 2-Acyl-1,1,3,3-tetracyanopropenides.

    Science.gov (United States)

    Karpov, Sergey V; Grigor'ev, Arthur A; Kayukov, Yakov S; Karpova, Irina V; Nasakin, Oleg E; Tafeenko, Victor A

    2016-08-01

    A novel route for synthesis of 2-acyl-1,1,3,3-tetracyanopropenides (ATCN) salts in high yields and excellent purities starting from readily available methyl ketones, malononitrile, bromine, and alkali metal acetates is reported. The starting aryl(heteroaryl) methyl ketones were oxidized to the corresponding α-ketoaldehydes by new a DMSO-NaBr-H2SO4 oxidation system in yields up to 90% within a short reaction time of 8-10 min. The subsequent stages of ATCN preparation are realized in aqueous media without use of any toxic solvents, in accordance with principle 5 of "green chemistry". Lithium, sodium, potassium, rubidium, and cesium 2-benzoyl-1,1,3,3-tetracyanopropenides were characterized by X-ray diffraction analysis. These salts show a good potential for synthesis of five- and six-membered heterocycles and may serve as potentially useful ligands in coordination and supramolecular chemistry. PMID:27384963

  16. Heavy main-group iodometallates hybridized by alkali metal via 1,10-Phenanthroline-5,6-dione

    Indian Academy of Sciences (India)

    Mengfan Yin; Gengxing Cai; Peng Wang; Xihui Chao; Jibo Liu; Haohong Li; Zhirong Chen

    2015-09-01

    Alkali metals were introduced into heavy main-group iodometallates to get two new IA/IVAheterometallic frameworks [PbI3K(pdon)(H2O)2] (1) and {[Pb3I9K2(pdon)2(H3O)]·H2O} (2) (pdon=1,10-phenanthroline-5,6-dione), which were obtained as single phases by hydrothermal method at different pH values. Compounds 1 and 2 are three-dimensional heterometallic frameworks constructed from the linkage of pdon ligand between iodometallate chains and potassium oxides/iodide clusters. Specially, these two heterometallic frameworks exhibit broadened absorption bands at 700 and 750 nm compared with those of bulk PbI2 and pdon ligand. The band gap of 2 is wider than that of 1, which is due to the absence of · · · interaction in 2. Their thermal stabilities are also discussed.

  17. Synthesis and Crystal Structure of A New Armed-tetraazacrown Ether and Its Liquid Membrane Transport of Alkali Metal Cations

    Institute of Scientific and Technical Information of China (English)

    马淑兰; 朱文祥; 董淑静; 郭倩玲; 佘远斌

    2003-01-01

    A new tetra-N-substituted tetraazacrown ether derivative, 4,7,13,16-tetra ( 2-cyanobenzyl)-1, 10-dioxa-4, 7, 13, 16-tetraazacy-dooctademne, C44H48N8O2, has been synthesized and struc-turally characterized. It crystallizes in the monoclinic system,Slmeegroup P21/c with a = 1.1176(3) nm, b =2.1906(7) nm,c=0.8430(3)nm, V=2.0132(10)nm3, β = 102.740(5)°,Z=4, Dc= 1.189 g/cm3, final R1=0.0460, wR2=0.0803.The liquid membrane transports of alkali metal cations using the new macrocyde as the ion-carrier were also studied. Com-pared with some macrocyclic ligands, our newly synthesized lig.and showed a good selectivity ratio for Na Na+/Li+.

  18. The Trapping and Cooling of Alkalis Metal Atoms%碱金属原子的囚禁与冷却

    Institute of Scientific and Technical Information of China (English)

    邓海明; 李璋

    2012-01-01

      描述了如何利用激光以及磁场构建光学粘胶、激光阱、磁阱、磁光阱等实现对碱金属的囚禁与冷却,旨在明晰的呈现BEC实验实现的关键技术、物理原理以及各种装置的优缺点。%  This essay describes how to use laser and magnetic field to construct optical molasses ,laser trap ,mag-netic trap and magneto -optical trap to trap and cool alkali-metal atoms .It presents clearly the key experimental technologies of Bose-Einstein condensate ,the physical principle and the relative advantages and disadvantages of different equipments .

  19. Hyperfine-induced quadrupole moments of alkali-metal atom ground states and their implications for atomic clocks

    CERN Document Server

    Derevianko, Andrei

    2016-01-01

    Spherically-symmetric ground states of alkali-metal atoms do not posses electric quadrupole moments. However, the hyperfine interaction between nuclear moments and atomic electrons distorts the spherical symmetry of electronic clouds and leads to non-vanishing atomic quadrupole moments. We evaluate these hyperfine-induced quadrupole moments using techniques of relativistic many-body theory and compile results for Li, Na, K, Rb, and Cs atoms. For heavy atoms we find that the hyperfine-induced quadrupole moments are strongly (two orders of magnitude) enhanced by correlation effects. We further apply the results of the calculation to microwave atomic clocks where the coupling of atomic quadrupole moments to gradients of electric fields leads to clock frequency uncertainties. We show that for $^{133}$Cs atomic clocks, the spatial gradients of electric fields must be smaller than $30 \\, \\mathrm{V}/\\mathrm{cm}^2$ to guarantee fractional inaccuracies below $10^{-16}$.

  20. Viscometric and thermodynamic studies of interactions in ternary solutions containing sucrose and aqueous alkali metal halides at 293.15, 303.15 and 313.15 K

    Indian Academy of Sciences (India)

    Reena Gupta; Mukhtar Singh

    2005-05-01

    Viscosities and densities of sucrose in aqueous alkali metal halide solutions of different concentrations in the temperature range 293.15 to 313.15 K have been measured. Partial molar volumes at infinite dilution ($V_{2}^{0}$) of sucrose determined from apparent molar volume ($\\phi_v$) have been utilized to estimate partial molar volumes of transfer ($V^{0}_{2,tr}$) for sucrose from water to alkali metal halide solutions. The viscosity data of alkali metal halides in purely aqueous solutions and in the presence of sucrose at different temperatures (293.15, 303.15 and 313.5 K) have been analysed by the Jones-Dole equation. The nature and magnitude of solute-solvent and solute-solute interactions have been discussed in terms of the values of limiting apparent molar volume ($\\phi^{0}_{v}$), slope ($S_{v}$) and coefficients of the Jones-Dole equation. The structuremaking and structure-breaking capacities of alkali metal halides in pure aqueous solutions and in the presence of sucrose have been ascertained from temperature dependence of $\\phi^{0}_{v}$.

  1. Diffusion of Rb atoms in paraffin - coated resonant vapor cells

    CERN Document Server

    Atutov, S N; Plekhanov, A I; Sorokin, V A; Yakovlev, A V

    2016-01-01

    We present the results of a study of the diffusion of Rb atoms in paraffin - coated resonant vapor cells. We have modeled the Rb diffusion both in the cell and in the coating, assuming that the main loss of Rb atoms is due to the physical absorption of the atoms by the glass substrate. It is demonstrated that the equilibrium atomic density in the cell is a monotonic function of the thickness of the paraffin coating: the density increases with an increase in the thickness of the coating. The diffusion coefficient for rubidium in paraffin thin films has been determined to be equal to 4,7*10^-7 cm^2/s. The results of the experiment might be useful for a better understanding of the details involved in the processes of the interaction of alkali atoms with a paraffin coating.

  2. Alkali Metal Rankine Cycle Boiler Technology Challenges and Some Potential Solutions for Space Nuclear Power and Propulsion Applications

    Science.gov (United States)

    Stone, James R.

    1994-01-01

    Alkali metal boilers are of interest for application to future space Rankine cycle power conversion systems. Significant progress on such boilers was accomplished in the 1960's and early 1970's, but development was not continued to operational systems since NASA's plans for future space missions were drastically curtailed in the early 1970's. In particular, piloted Mars missions were indefinitely deferred. With the announcement of the Space Exploration Initiative (SEI) in July 1989 by President Bush, interest was rekindled in challenging space missions and, consequently in space nuclear power and propulsion. Nuclear electric propulsion (NEP) and nuclear thermal propulsion (NTP) were proposed for interplanetary space vehicles, particularly for Mars missions. The potassium Rankine power conversion cycle became of interest to provide electric power for NEP vehicles and for 'dual-mode' NTP vehicles, where the same reactor could be used directly for propulsion and (with an additional coolant loop) for power. Although the boiler is not a major contributor to system mass, it is of critical importance because of its interaction with the rest of the power conversion system; it can cause problems for other components such as excess liquid droplets entering the turbine, thereby reducing its life, or more critically, it can drive instabilities-some severe enough to cause system failure. Funding for the SEI and its associated technology program from 1990 to 1993 was not sufficient to support significant new work on Rankine cycle boilers for space applications. In Fiscal Year 1994, funding for these challenging missions and technologies has again been curtailed, and planning for the future is very uncertain. The purpose of this paper is to review the technologies developed in the 1960's and 1970's in the light of the recent SEI applications. In this way, future Rankine cycle boiler programs may be conducted most efficiently. This report is aimed at evaluating alkali metal boiler

  3. Modulation transfer spectroscopy in a lithium atomic vapor cell.

    Science.gov (United States)

    Sun, Dali; Zhou, Chao; Zhou, Lin; Wang, Jin; Zhan, Mingsheng

    2016-05-16

    We have investigated modulation transfer spectroscopy of D2 transitions of 7Li atoms in a vapor cell. The role of the intensity of the probe beam in the spectrum is important, we have seen unique characteristics of the signal in the crossover peak. In order to find the best signal for laser locking, the slope and frequency offset of the zero-crossing signal are determined. The dependence of the modulation transfer spectra on polarizations of pump and probe beam is demonstrated. The residual amplitude modulation in the system is also considered, and the distortion of the spectra due to the modulation is analyzed. It was found that the crossover peak is more suitable for frequency stabilization due to its better residual amplitude modulation compensation. PMID:27409886

  4. Multinuclear Alkali Metal Complexes of a Triphenylene-Based Hexamine and the Transmetalation to Tris(N-heterocyclic tetrylenes) (Ge, Sn, Pb).

    Science.gov (United States)

    Zhong, Fei; Yang, Xiaodong; Shen, Lingyi; Zhao, Yanxia; Ma, Hongwei; Wu, Biao; Yang, Xiao-Juan

    2016-09-01

    A C3-symmetric hexamine (LH6) based on the triphenylene and ortho-phenylenediamine (PDAH2) skeletons has been synthesized, and was partially or fully deprotonated upon treatment with alkali metal agents to afford amino-amido or diamido coordination sites. Four alkali metal complexes, the dinuclear [Na2(LH4)(DME)5] (1) and [K2(LH4)(DME)4] (2), trinuclear [K3(LH3)(DME)6] (3), and hexanuclear [Li6(L)(DME)6] (4), were obtained and used in transmetalation/ligand exchange with other metals. The hexalithium salt of the fully deprotonated ligand, [Li6L], reacted with heavier group 14 element halides to yield three tris(N-heterocyclic tetrylenes), the germylene [Ge3(L)] (5), stannylene [Sn3(L)] (6), and plumbylene [Pb3(L)] (7). The synthesis and crystal and electronic structures of these compounds are reported. PMID:27525542

  5. A curious interplay in the films of N-heterocyclic carbene PtII complexes upon deposition of alkali metals

    Science.gov (United States)

    Makarova, Anna A.; Grachova, Elena V.; Niedzialek, Dorota; Solomatina, Anastasia I.; Sonntag, Simon; Fedorov, Alexander V.; Vilkov, Oleg Yu.; Neudachina, Vera S.; Laubschat, Clemens; Tunik, Sergey P.; Vyalikh, Denis V.

    2016-05-01

    The recently synthesized series of PtII complexes containing cyclometallating (phenylpyridine or benzoquinoline) and N-heterocyclic carbene ligands possess intriguing structures, topologies, and light emitting properties. Here, we report curious physicochemical interactions between in situ PVD-grown films of a typical representative of the aforementioned PtII complex compounds and Li, Na, K and Cs atoms. Based on a combination of detailed core-level photoelectron spectroscopy and quantum-chemical calculations at the density functional theory level, we found that the deposition of alkali atoms onto the molecular film leads to unusual redistribution of electron density: essential modification of nitrogen sites, reduction of the coordination PtII centre to Pt0 and decrease of electron density on the bromine atoms. A possible explanation for this is formation of a supramolecular system “Pt complex-alkali metal ion” the latter is supported by restoration of the system to the initial state upon subsequent oxygen treatment. The discovered properties highlight a considerable potential of the PtII complexes for a variety of biomedical, sensing, chemical, and electronic applications.

  6. Equilibrium electrode U(4)-U and redox U(4)-U(3) potentials in molten alkali metal chlorides medium

    International Nuclear Information System (INIS)

    Conditional standard electrode potentials of uranium are determined for diluted solutions of its tetrachloride in alkali metal chloride melts (LiCl, NaCl, NaCl-KCl, KCl, RbCl and CsCl) when using U(4) ion activity coefficient values experimentally found by the tensimetric method. These potentials shift to the electronegative side at the temperature decrease and alkali cation radius increase rsub(Msup(+)) according to the empiric ratio E*U(4)-U= -3.06+6.87x10-4 T-(1.67-10-4T-0.44) 1/rsub(Msup(+)) +-0.01. The temperature dependences of formal conditional redox potentials of the U(4)-U(3) system for above melted chlorides are estimated. The E*U(4)-U(3) value also becomes more electronegative in the series LiCl, NaCl, NaCl-KCl, KCl, RbCl and CsCl. This alternation is satisfactorily described by the empiric expression E*U(4)-U(3)= -1.74+1.74x10-4T-(0.71x10-4T-0.20) 1rsub(Msup(+)) +-0.05. The calculated values Eu*(4)-U(3) are compared with those directly measured for the NaCl-KCl equimolar mixture and 3LiCl-2KCl eutectic mixture. A satisfactory confirmity has been observed

  7. The electronic properties of bare and alkali metal adsorbed two-dimensional GeSi alloy sheet

    Science.gov (United States)

    Qiu, Wenhao; Ye, Han; Yu, Zhongyuan; Liu, Yumin

    2016-09-01

    In this paper, the structural and electronic properties of both bare and alkali metal (AM) atoms adsorbed two-dimensional GeSi alloy sheet (GeSiAS) are investigated by means of first-principles calculations. The band gaps of bare GeSiAS are shown slightly opened at Dirac point with the energy dispersion remain linear due to the spin-orbit coupling effect at all concentrations of Ge atoms. For metal adsorption, AM atoms (including Li, Na and K) prefer to occupy the hexagonal hollow site of GeSiAS and the primary chemical bond between AM adatom and GeSiAS is ionic. The adsorption energy has an increase tendency with the increase of the Ge concentration in supercell. Besides, single-side adsorption of AM atoms introduces band gap at Dirac point, which can be tuned by the Ge concentration and the species of AM atoms. The strong relation between the band gaps and the distribution of Si and Ge atoms inside GeSiAS are also demonstrated. The opened band gaps of AM covered GeSiAS range from 14.8 to 269.1 meV along with the effective masses of electrons ranging from 0.013 to 0.109 me, indicating the high tunability of band gap as well as high mobility of carriers. These results provide a development in two-dimensional alloys and show potential applications in novel micro/nano-electronic devices.

  8. Evidence for alkali metal induced intermolecular acetylenic hydrogen atom transfer between hydrogen-bonded alkyne complexes in solid argon

    International Nuclear Information System (INIS)

    Condensation of acetylene, propyne, and 2-butyne/acetylene mixtures with heavy alkali metal atoms (Na, K, Cs) in an argon matrix at 15 K has led to the appearance of infrared absorptions due to ethylene, propylene, and trans-2-butene, respectively. These results stand in sharp contrast with the products obtained with lithium. Isotopic studies have shown that ethylene formation involved three different acetylene molecules and evidenced a difference in the product yield with hydrogen vs. deuterium as well as a preference for trans- vs. cis-C2H2D2 formation, which is discussed and rationalized by differences in the zero point energies for the different mixed deuterium isotopes of the intermediate vinyl radical. This trend is amplified by methyl substitution. Spectroscopic evidence was found in these experiments for cesium acetylide (Cs+C2H-) and a cesium-acetylene π complex, which are involved in the intermolecular acetylenic hydrogen atom transfer process. 26 references, 3 figures, 2 tables

  9. Effect of semicore banding on heavy-alkali-metal lattice constants: Corrections to the frozen-core approximation

    Science.gov (United States)

    Yang, L. H.; Smith, A. P.; Benedek, R.; Koelling, D. D.

    1993-06-01

    Equilibrium lattice constants and bulk moduli of the heavy alkali metals K, Rb, and Cs were calculated using the Troullier-Martins pseudopotentials and plane-wave basis functions. The treatment of the outermost p-shell electrons as Bloch states yielded lattice constants 2-3 % larger than those obtained within the frozen-core approximation (including the partial core correction of Louie, Froyen, and Cohen [Phys. Rev. B 26, 1738 (1982)]), which narrows a long-standing discrepancy between local-density functional theory and experiment. Predicted bulk moduli are 30-50 % larger than measured values, within either treatment. The band dispersion of the semicore states (with bandwidths 0.067, 0.14, and 0.25 eV for K, Rb, and Cs) is attributed primarily to core-electron-conduction-electron hybridization rather than direct core-core overlap. The semicore density of states has a flat line shape, rather than the peaked shape expected for an idealized tight-binding band.

  10. Hartree-Fock ground-state properties for the group 1 alkali metals and the group 11 noble metals

    International Nuclear Information System (INIS)

    In order to use wavefunction-based correlation methods in solids it is necessary to have reliable Hartree-Fock results for the infinite system of interest. Therefore we performed Hartree-Fock calculations for the group 1 alkali metals (Li to Cs) and group 11 noble metals (Cu, Ag and Au). We optimized a basis set of valence-double-ζ quality for the periodic system. For the lighter atoms all-electron basis sets are applied, whereas for the heavier atoms small-core pseudopotentials with the corresponding basis sets were used to deal with the scalar-relativistic effects. We determine the cohesive energy, the lattice constant and the bulk modulus of the systems at the Hartree-Fock level. We use the counterpoise correction for the free atom to minimize the basis set superposition error occurring for finite basis sets. The effects due to the counterpoise correction not only for the cohesive energy but also for the lattice structure and bulk modulus are discussed in detail

  11. FP-APW+lo calculations of the electronic and optical properties of alkali metal sulfides under pressure

    International Nuclear Information System (INIS)

    The electronic and optical properties of M2S (M = Li, Na, K and Rb) compounds in the cubic antifluorite structure have been calculated, using a full relativistic version of the full-potential augmented plane-wave plus local orbitals method based on density functional theory, within both the local density approximation (LDA) and the generalized gradient approximation (GGA). Moreover, the Engel-Vosko GGA formalism (EV-GGA) is applied so as to optimize the corresponding potential for band structure calculations. The calculated equilibrium lattices and bulk moduli are in good agreement with the available data. Band structure, density of states, electron charge density and pressure coefficients of energy gaps are given. Results obtained for band structure using EV-GGA are larger than those with LDA and GGA. It is found that the spin-orbit coupling lifts the triple degeneracy at the Γ point and the double degeneracy at the X point. The analysis of the electron charge density shows that the M-S bonds have a significant ionic character. The complex dielectric functions ε2(ω) for alkali metal sulfides were calculated for radiation up to 30 eV and the assignment of the critical points to the band structure energy differences at various points of the Brillouin zone was made. The pressure and volume dependence of the static dielectric constant and the refractive index are calculated.

  12. Release and sorption of alkali metals in coal fired combined cycle power systems; Freisetzung und Einbindung von Alkalimetallverbindungen in kohlebefeuerten Kombikraftwerken

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Michael

    2009-07-01

    Coal fired combined cycle power systems will be a sufficient way to increase the efficiency of coal combustion. However, combined cycle power systems require a reliable hot gas cleanup. Especially alkali metals, such as sodium and potassium, can lead to hot corrosion of the gas turbine blading if they condensate as sulphates. The actual work deals with the release and sorption of alkali metals in coal fired combined cycle power systems. The influence of coal composition, temperature and pressure on the release of alkali species in coal combustion was investigated and the relevant release mechanisms identified. Alumosilicate sorbents have been found that reduce the alkali concentration in the hot flue gas of the Circulating Pressurized Fluidized Bed Combustion 2{sup nd} Generation (CPFBC 2{sup nd} Gen.) at 750 C to values sufficient for use in a gas turbine. Accordingly, alumosilicate sorbents working at 1400 C have been found for the Pressurized Pulverized Coal Combustion (PPCC). The sorption mechanisms have been identified. Thermodynamic calculations were performed to upscale the results of the laboratory experiments to conditions prevailing in power systems. According to these calculations, there is no risk of hot corrosion in both processes. Furthermore, thermodynamic calculations were performed to investigate the behaviour of alkali metals in an IGCC with integrated hot gas cleanup and H{sub 2} membrane for CO{sub 2} sequestration. (orig.)

  13. Chemical state analysis of trace-level alkali metals sorbed in micaceous oxide by total reflection X-ray photoelectron spectroscopy

    Science.gov (United States)

    Baba, Y.; Shimoyama, I.; Hirao, N.

    2016-10-01

    In order to determine the chemical states of radioactive cesium (137Cs or 134Cs) sorbed in clay minerals, chemical states of cesium as well as the other alkali metals (sodium and rubidium) sorbed in micaceous oxides have been investigated by X-ray photoelectron spectroscopy (XPS). Since the number of atoms in radioactive cesium is extremely small, we specially focused on chemical states of trace-level alkali metals. For this purpose, we have measured XPS under X-ray total reflection (TR) condition. For cesium, it was shown that ultra-trace amount of cesium down to about 100 pg cm-2 can be detected by TR-XPS. This amount corresponds to about 200 Bq of 137Cs (t1/2 = 30.2 y). It was demonstrated that ultra-trace amount of cesium corresponding to radioactive cesium level can be measured by TR-XPS. As to the chemical states, it was found that core-level binding energy in TR-XPS for trace-level cesium shifted to lower-energy side compared with that for thicker layer. A reverse tendency is observed in sodium. Based on charge transfer within a simple point-charge model, it is concluded that chemical bond between alkali metal and micaceous oxide for ultra-thin layer is more polarized that for thick layer.

  14. Study of Rb - vapor coated cell; atomic diffusion and cell curing process

    CERN Document Server

    Atutov, S N; Plekhanov, A I; Sorokin, V A

    2015-01-01

    We present the results of the study of an optical resonant cell filled by a vapor of the Rb atoms and coated with a non-stick polydimethylsiloxane (PDMS) polymer. We show that it is possible to define correctly the diffusion coefficient of the atoms in the coating, using geometric parameters of the cell and the vapor density in the cell volume only. The dependence of the diffusion coefficient on the cell curing time is presented. It is shown that the mysterious cell curing process can be explained in terms of the polymerization of the polymer coating by alkali atoms. Anomalous long dwell time of the Rb atoms on the PDMS coating is discussed as well.

  15. Characterization of high-temperature performance of cesium vapor cells with anti-relaxation coating

    CERN Document Server

    Li, Wenhao; Peng, Xiang; Pustelny, Szymon; Wickenbrock, Arne; Guo, Hong; Budker, Dmitry

    2016-01-01

    Vapor cells with antirelaxation coating are widely used in modern atomic physics experiments due to the coating's ability to maintain the atoms' spin polarization during wall collisions. We characterize the performance of vapor cells with different coating materials by measuring longitudinal spin relaxation and vapor density at temperatures up to 95{\\deg}C. We found that the spin-projection-noise-limited sensitivity for atomic magnetometers with such cells improves with temperature, which demonstrates the potential of antirelaxation coated cells in applications of future high-sensitivity magnetometers.

  16. Low temperature alkali metal-sulfur batteries. Final report, December 1, 1974-November 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Brummer, S.B.; Rauh, R.D.; Abraham, K.M.; Dampier, F.W.; Subrahmanyam, V.; Pearson, G.F.; Surprenant, J.K.; Buzby, J.M.

    1980-03-01

    Work on the development of rechargeable, ambient-temperature Li/sulfur and Li/metal sulfide batteries is reported. The Li/S system has the cathode material dissolved in the electrolyte, as Li/sub 2/S/sub n/. Tetrahydrofuran, 1M LiAsF/sub 6/, is one of the more attractive electrolytes discovered for this cell, since it can dissolve up to approx. 10M S as Li/sub 2/Sn. Despite the oxidative nature of the electrolyte, Li is stable in it and can be electrodeposited from it on battery charge. Cells of the configuration Li 5M S (as Li/sub 2/S/sub n/), THF, 1M LiAsF/sub 6//carbon can be discharged at 50/sup 0/C with a utilization of nearly 1.5e/sup -//S at the C/3 rate. This corresponds to the rate-capacity goal for this battery in its proposed vehicular or load-leveling applications. Further improvements in rate are possible. Rechargeability of 135 cycles of 0.1 e/sup -//S and approx. 45 cycles of 0.5 e/sup -//S was demonstrated. The self-discharge reaction keeps the Li electrode free of electrically isolated dendrites. Ultimate failure on cycling is due to cathode depletion via precipitation of Li/sub 2/S on the anode in a form insoluble in the electrolyte. Attempts to solubilize the Li/sub 2/S by the internal generation of an oxidizing scavenger (e.g., Br/sub 2/) or by addition of Lewis acids have met only with limited success. Cells of configuration Li/THF, 1M LiAsF/sub 6//insoluble metal sulfide were investigated, using the following cathodes: CuS, NiS, SiS/sub 2/, MnS/sub 2/, FeS, and Bi/sub 2/S/sub 3/. Of these, the most promising new material in terms of energy density and rechargeability is CuS. Well over 100 cycles for Li/CuS cells with moderate cathode loadings were demonstrated. CuS compares favorably with TiS/sub 2/ in terms of energy density and rechargeability and is superior in terms of economics. 39 figures, 19 tables.

  17. Alkali metal Rankine cycle boiler technology challenges and some potential solutions for space nuclear power and propulsion applications

    Energy Technology Data Exchange (ETDEWEB)

    Stone, J.R.

    1994-07-01

    Alkali metal boilers are of interest for application to future space Rankine cycle power conversion systems. Significant progress on such boilers was accomplished in the 1960's and early 1970's, but development was not continued to operational systems since NASA's plans for future space missions were drastically curtailed in the early 1970's. In particular, piloted Mars missions were indefinitely deferred. With the announcement of the Space Exploration Initiative (SEI) in July 1989 by President Bush, interest was rekindled in challenging space missions and, consequently in space nuclear power and propulsion. Nuclear electric propulsion (NEP) and nuclear thermal propulsion (NTP) were proposed for interplanetary space vehicles, particularly for Mars missions. The potassium Rankine power conversion cycle became of interest to provide electric power for NEP vehicles and for 'dual-mode' NTP vehicles, where the same reactor could be used directly for propulsion and (with an additional coolant loop) for power. Although the boiler is not a major contributor to system mass, it is of critical importance because of its interaction with the rest of the power conversion system; it can cause problems for other components such as excess liquid droplets entering the turbine, thereby reducing its life, or more critically, it can drive instabilities-some severe enough to cause system failure. Funding for the SEI and its associated technology program from 1990 to 1993 was not sufficient to support significant new work on Rankine cycle boilers for space applications. In Fiscal Year 1994, funding for these challenging missions and technologies has again been curtailed, and planning for the future is very uncertain. The purpose of this paper is to review the technologies developed in the 1960's and 1970's in the light of the recent SEI applications. In this way, future Rankine cycle boiler programs may be conducted most efficiently.

  18. Alkali metal ion induced cube shaped mesoporous hematite particles for improved magnetic properties and efficient degradation of water pollutants.

    Science.gov (United States)

    Roy, Mouni; Naskar, Milan Kanti

    2016-07-27

    Mesoporous cube shaped hematite (α-Fe2O3) particles were prepared using FeCl3 as an Fe(3+) precursor and 1-butyl-3-methylimidazolium bromide (ionic liquid) as a soft template in the presence of different alkali metal (lithium, sodium and potassium) acetates, under hydrothermal conditions at 150 °C/4 h followed by calcination at 350 °C. The formation of the α-Fe2O3 phase in the synthesized samples was confirmed by XRD, FTIR and Raman spectroscopy. Unlike K(+) ions, intercalation of Li(+) and Na(+) ions occurred in α-Fe2O3 crystal layers as evidenced by XRD and Raman spectroscopy. Electron microscopy (FESEM and TEM) images showed the formation of cube-like particles of different sizes in the presence of Li(+), Na(+) and K(+) ions. The mesoporosity of the products was confirmed by N2 adsorption-desorption studies, while their optical properties were analyzed by UV-DRS. Na(+) ion intercalated α-Fe2O3 microcubes showed improved coercivity (5.7 kOe) due to increased strain in crystals, and shape and magnetocrystalline anisotropy. Temperature dependent magnetization of the samples confirmed the existence of Morin temperature in the range of 199-260 K. Catalytic degradation of methylene blue (MB), a toxic water pollutant, was studied using the synthesized products via a heterogeneous photo-Fenton process. The degradation products were traced by electrospray ionization-mass spectrometry (ESI-MS). The α-Fe2O3 microcubes obtained in the presence of Na(+) ions exhibited a more efficient degradation of MB to non-toxic open chain products. PMID:27406648

  19. Controlling atomic vapor density in paraffin-coated cells using light-induced atomic desorption

    CERN Document Server

    Karaulanov, T; English, D; Rochester, S M; Rosen, Y; Tsigutkin, K; Budker, D; Alexandrov, E B; Balabas, M V; Kimball, D F Jackson; Narducci, F A; Pustelny, S; Yashchuk, V V

    2008-01-01

    Atomic-vapor density change due to light induced atomic desorption (LIAD) is studied in paraffin-coated rubidium, cesium, sodium and potassium cells. In the present experiment, low-intensity probe light is used to obtain an absorption spectrum and measure the vapor density, while light from an argon-ion laser or discharge lamp is used for desorption. Potassium is found to exhibit significantly weaker LIAD from paraffin compared to Rb and Cs, and we were unable to observe LIAD with sodium. A simple LIAD model is applied to describe the observed vapor-density dynamics, and the role of the cell's stem is explored through the use of cells with lockable stems. The results of this work could be used to assess the use of LIAD for vapor-density control in magnetometers, clocks, and gyroscopes utilizing coated cells.

  20. CO2 Extraction from Ambient Air Using Alkali-Metal Hydroxide Solutions Derived from Concrete Waste and Steel Slag

    Science.gov (United States)

    Stolaroff, J. K.; Lowry, G. V.; Keith, D. W.

    2003-12-01

    To mitigate global climate change, deep reductions in CO2 emissions are required in the coming decades. Carbon sequestration will play a crucial role in this reduction. Early adoption of carbon sequestration in low-cost niche markets will help develop the technology and experience required for large-scale deployment. One such niche may be the use of alkali metals from industrial waste streams to form carbonate minerals, a safe and stable means of sequestering carbon. In this research, the potential of using two industrial waste streams---concrete and steel slag---for sequestering carbon is assessed. The scheme is outlined as follows: Ca and Mg are leached with water from a finely ground bed of steel slag or concrete. The resulting solution is sprayed through air, capturing CO2 and forming solid carbonates, and collected. The feasibility of this scheme is explored with a combination of experiments, theoretical calculations, cost accounting, and literature review. The dissolution kinetics of steel slag and concrete as a function of particle size and pH is examined. In stirred batch reactors, the majority of Ca which dissolved did so within the first hour, yielding between 50 and 250 (mg; Ca)/(g; slag) and between 10 and 30 (mg; Ca)/(g; concrete). The kinetics of dissolution are thus taken to be sufficiently fast to support the type of scheme described above. As proof-of-concept, further experiments were performed where water was dripped slowly through a stagnant column of slag or concrete and collected at the bottom. Leachate Ca concentrations in the range of 15 mM were achieved --- sufficient to support the scheme. Using basic physical principles and numerical methods, the quantity of CO2 captured by falling droplets is estimated. Proportion of water loss and required pumping energy is similarly estimated. The results indicate that sprays are capable of capturing CO2 from the air and that the water and energy requirements are tractable. An example system for

  1. High-temperature, high-pressure hydrothermal synthesis, characterization, and structural relationships of mixed-alkali metals uranyl silicates

    Science.gov (United States)

    Chen, Yi-Hsin; Liu, Hsin-Kuan; Chang, Wen-Jung; Tzou, Der-Lii; Lii, Kwang-Hwa

    2016-04-01

    Three mixed-alkali metals uranyl silicates, Na3K3[(UO2)3(Si2O7)2]·2H2O (1), Na3Rb3[(UO2)3(Si2O7)2] (2), and Na6Rb4[(UO2)4Si12O33] (3), have been synthesized by high-temperature, high-pressure hydrothermal reactions at 550 °C and 1440 bar, and characterized by single-crystal X-ray diffraction, photoluminescence, and thermogravimetric analysis. Compound 1 and 2 are isostructural and contain layers of uranyl disilicate. The smaller cation, Na+, is located in the intralayer channels, whereas the larger cations, K+ and Rb+, and water molecule are located in the interlayer region. The absence of lattice water in 2 can be understood according to the valence-matching principle. The structure is related to that of a previously reported mixed-valence uranium(V,VI) silicate. Compound 3 adopts a 3D framework structure and contains a unique unbranched dreier fourfold silicate chain with the structural formula {uB,41∞}[3Si12O33] formed of Q2, Q3, and Q4 Si. The connectivity of the Si atoms in the Si12O3318- anion can be interpreted on the basis of Zintl-Klemm concept. Crystal data for compound 1: triclinic, P-1, a=5.7981(2) Å, b=7.5875(3) Å, c=12.8068(5) Å, α=103.593(2)°, β=102.879(2)°, γ=90.064(2)°, V=533.00(3) Å3, Z=1, R1=0.0278; compound 2: triclinic, P-1, a=5.7993(3) Å, b=7.5745(3) Å, c=12.9369(6) Å, α=78.265(2)°, β=79.137(2)°, γ=89.936(2)°, V=546.02(4) Å3, Z=1, R1=0.0287; compound 3: monoclinic, C2/m, a=23.748(1) Å, b=7.3301(3) Å, c=15.2556(7) Å, β=129.116(2)°, V=2060.4(2) Å3, Z=2, R1=0.0304.

  2. Spectrum, radial wave functions, and hyperfine splittings of the Rydberg states in heavy alkali-metal atoms

    Science.gov (United States)

    Sanayei, Ali; Schopohl, Nils

    2016-07-01

    We present numerically accurate calculations of the bound-state spectrum of the highly excited valence electron in the heavy alkali-metal atoms solving the radial Schrödinger eigenvalue problem with a modern spectral collocation method that applies also for a large principal quantum number n ≫1 . As an effective single-particle potential we favor the reputable potential of Marinescu et al. [Phys. Rev. A 49, 982 (1994)], 10.1103/PhysRevA.49.982. Recent quasiclassical calculations of the quantum defect of the valence electron agree for orbital angular momentum l =0 ,1 ,2 ,... overall remarkably well with the results of the numerical calculations, but for the Rydberg states of rubidium and also cesium with l =3 this agreement is less fair. The reason for this anomaly is that in rubidium and cesium the potential acquires for l =3 deep inside the ionic core a second classical region, thus invalidating a standard Wentzel-Kramers-Brillouin (WKB) calculation with two widely spaced turning points. Comparing then our numerical solutions of the radial Schrödinger eigenvalue problem with the uniform analytic WKB approximation of Langer constructed around the remote turning point rn,j ,l (" close=")n -δ0)">+ we observe everywhere a remarkable agreement, apart from a tiny region around the inner turning point rn,j ,l (-). For s states the centrifugal barrier is absent and no inner turning point exists: rn,j ,0 (-)=0 . With the help of an ansatz proposed by Fock we obtain for the s states a second uniform analytic approximation to the radial wave function complementary to the WKB approximation of Langer, which is exact for r →0+ . From the patching condition, that is, for l =0 the Langer and Fock solutions should agree in the intermediate region 0 application we consider recent spectroscopic data for the hyperfine splittings of the isotopes 85Rb and 87Rb and find a remarkable agreement with the predicted scaling relation An,j ,0 (HFS )=const .

  3. Calculation of van der Walls coefficients of alkali metal clusters by hydrodynamic approach to time-dependent density-functional theory

    CERN Document Server

    Banerjee, A; Banerjee, Arup; Harbola, Manoj K.

    2004-01-01

    In this paper we employ the hydrodynamic formulation of time-dependent density functional theory to obtain the van der Waal coefficients $C_{6}$ and $C_{8}$ of alkali-metal clusters of various sizes including very large clusters. Such calculation becomes computationally very demanding in the orbital-based Kohn-Sham formalism, but quite simple in the hydrodynamic approach. We show that for interactions between the clusters of same sizes, $C_{6}$ and $C_{8}$ sale as the sixth and the eighth power of the cluster radius rsepectively, and approach the respective classically predicted values for the large size clusters.

  4. Directed reflectivity, long life AMTEC condenser (DRC). Final report of Phase II SBIR program[Alkali Metal ThermoElectric Converter

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, Thomas K.

    2001-09-10

    The Alkali Metal Thermal to Electric Converter (AMTEC) is a static energy conversion device that operates at high thermal to electric conversion efficiencies that are essentially independent of size, have reached 19% and are expected to reach 25% to 30% in 1997. AMTEC systems have been chosen by NASA and DOE for spacecraft applications and have considerable promise for a wide variety of terrestrial applications. Reduction of parasitic heat losses in AMTEC systems related to radiative heat transfer from the hot side to the condenser can make a substantial contribution to system efficiency. Through design, analysis and the fabrication and testing of cells and systems, the proposed program to develop a Directed Reflectivity Condenser (DRC) has investigated the feasibility of an improved AMTEC condenser component. Phase 1 work showed the potential for adding from 4% to 7% to overall system efficiency for identical operating conditions using the concept. A detailed thermal analysis of several DRC capped cell designs was carried out and some of the conditions under which a DRC, used as the condenser at an end cap of a cylindrical converter, can reduce thermal radiation related losses were determined. A model experimental converter was built and tested to compare DRC and planar condenser surfaces. The results of both analysis and experiment indicate that for moderate aspect ratios of a cylindrical, end condensed converter, the DRC can reduce overall thermal losses by up to 4%. The initial effort in Phase 2 extended the analysis to a novel 150 watt radial AMTEC cell design. This analysis indicated that for the effective aspect ratio of this new converter design, the system performance at the 100+ watt level was not significantly improved by use of a DRC type condenser surface. Further analyses however showed that for cylindrical, end-condensed converters, optimized for use with internal radiation shields, the use of DRC surfaces on the side walls of the converter could be

  5. Calculation of Interaction Parameters from Immiscible Phase Diagram of Alkali Metal or Alkali Earth Metal-Halide System by Means of Subregular Solution Model

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, the interaction parameters in the subregular solution model, λ1 and λ2, are regarded as a linear function of temperature, T. Therefore, the molar excess Gibbs energy of A-B binary system may be reexpressed as follows: The calculation of the model parameters, λ11, λ12, λ21 and λ22, was carried out numerically from the phase diagrams for 11 alkali metal-alkali halide or alkali earth metal-halide systems.In addition, artificial neural network trained by known data has been used to predict the values of these model parameters. The predicted results are in good agreement with the.calculated ones. The applicability of the subregular solution model to the alkali metal-alkali halide or alkali earth metal-halide systems were tested by comparing the available experimental composition along the boundary of miscibility gap with the calculated ones which were obtained by using genetic algorithm. The good agreement between the calculated and experimental results across the entire liquidus is valid evidence in support of the model.

  6. Fragmentation study of rutin, a naturally occurring flavone glycoside cationized with different alkali metal ions, using post-source decay matrix-assisted laser desorption/ionization mass spectrometry.

    Science.gov (United States)

    Kéki, S; Deák, G; Zsuga, M

    2001-12-01

    A post-source decay matrix-assisted laser desorption/ionization mass spectrometric (PSD-MALDI-MS) study of rutin, a naturally occurring flavone glycoside cationized with different alkali metal ions, is reported. The fragmentations of rutin were performed by selecting the [R + Cat]+ peaks for PSD, where R represents a rutin molecule and Cat an alkali metal ion (Li+, Na+, K+). The PSD-MALDI mass spectra showed, depending on Cat, different fragmentation patterns with respect to both the quality and quantity of the fragment ions formed. The intensity of fragmentation decreased in the order Li+ > Na+ > K+. The fragmentation mechanism and an explanation for the observed differences are suggested.

  7. Review on utilization of the pervaporation membrane for passive vapor feed direct methanol fuel cell

    International Nuclear Information System (INIS)

    The Direct Methanol Fuel Cell (DMFC) is a promising portable power source for mobile electronic devices because of its advantages including easy fuel storage, high energy density, low temperature operation and compact structure. In DMFC, methanol is used as a fuel source where it can be fed in liquid or vapor phase. However, the vapor feed DMFC has an advantage over the liquid feed system as it has the potential to have a higher operating temperature to increase the reaction rates and power outputs, to enhance the mass transfers, to reduce methanol crossover, reliable for high methanol concentration and it can increase the fuel cell performance. Methanol vapor can be delivered to the anode by using a pervaporation membrane, heating the liquid methanol or another method that compatible. Therefore, this paper is a review on vapor feed DMFC as a better energy source than liquid feed DMFC, the pervaporation membrane used to vaporize methanol feed from the reservoir and its applications in vapor feed DMFC

  8. Alkali-vapor cell with metal coated windows for efficient application of an electric field

    Science.gov (United States)

    Sarkisyan, D.; Sarkisyan, A. S.; Guéna, J.; Lintz, M.; Bouchiat, M.-A.

    2005-05-01

    We describe the implementation of a cylindrical T-shaped alkali-vapor cell for laser spectroscopy in the presence of a longitudinal electric field. The two windows are used as two electrodes of the high-voltage assembly, which is made possible by a metallic coating which entirely covers the inner and outer sides of the windows except for a central area to let the laser beams in and out of the cell. This allows very efficient application of the electric field, up to 2kV/cm in a rather dense superheated vapor, even when significant photoemission takes place at the windows during pulsed laser irradiation. The body of the cell is made of sapphire or alumina ceramic to prevent large currents resulting from surface conduction observed in cesiated glass cells. The technique used to attach the monocrystalline sapphire windows to the cell body causes minimal stress birefringence in the windows. In addition, reflection losses at the windows can be made very small. The vapor cell operates with no buffer gas and has no magnetic part. The use of this kind of cell has resulted in an improvement of the signal-to-noise ratio in the measurement of parity violation in cesium vapor underway at ENS, Paris. The technique can be applied to other situations where a brazed assembly would give rise to unacceptably large birefringence in the windows.

  9. Loading a vapor cell magneto-optic trap using light-induced atom desorption

    CERN Document Server

    Anderson, B P

    2000-01-01

    Low intensity white light was used to increase the loading rate of $^{87}$Rb atoms into a vapor cell magneto-optic trap by inducing non-thermal desorption of Rb atoms from the stainless steel walls of the vapor cell. An increased Rb partial pressure reached a new equilibrium value in less than 10 seconds after switching on the broadband light source. After the source was turned off, the partial pressure returned to its previous value in $1/e$ times as short as 10 seconds.

  10. Dispersive radio frequency electrometry using Rydberg atoms in a prism-shaped atomic vapor cell

    Science.gov (United States)

    Fan, H. Q.; Kumar, S.; Kübler, H.; Shaffer, J. P.

    2016-05-01

    We introduce a method to measure radio frequency (RF) electric fields (E-fields) using atoms contained in a prism-shaped vapor cell. The method utilizes the concept of electromagnetically induced transparency with Rydberg atoms. The RF E-field induces changes in the index of refraction of the vapor resulting in deflection of the probe laser beam as it passes through the prism-shaped vapor cell. We measured a minimum RF E-field of 8.25 μ {{Vcm}}-1 with a sensitivity of ∼ 46.5 μ {{Vcm}}-1 {{Hz}}-1/2. The experimental results agree with a numerical model that includes dephasing effects. We discuss possible improvements to obtain higher sensitivity for RF E-field measurements.

  11. Coherent population trapping in small- and chip-scale 87Rb vapor cells with buffer gas

    Science.gov (United States)

    Ermak, S. V.; Semenov, V. V.; Petrenko, M. V.; Pyatyshev, E. N.

    2016-03-01

    The characteristics of coherent population trapping (CPT) signal were investigated in small-size glass vapor cells containing 87Rb and Ne buffer gas with narrow line-width laser pumping on D2 line. The parameters of CPT signals were measured using small-size vapor cells with Ne buffer gas pressure in the range of 200-400 Torr, cell temperature in the range of 65-120 ∘C and the values of laser pumping power of 30-400 μW/cm2. Optimal conditions, under which the minimal value of short-term instability of resonance line is achieved, were obtained in experiments. Orientation frequency shifts of CPT resonance using glass 87Rb vapor cells containing buffer gas and anti-relaxation coating were compared. CPT signals using vapor cells based on integrated technologies containing 87Rb in atmosphere of Ne were also investigated. The CPT signals with typical line widths of 2-3 kHz and signal-to-noise ratio of 1500 in 1 Hz bandwidth are observed, which allows one to provide relative frequency instability of 10-11 at 100 s.

  12. Alkali metal non-stoichiometric effects in (K{sub 0.5}Na{sub 0.5})NbO{sub 3} based piezoelectric ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S. C.; Yeo, H. G.; Cho, J. H.; Sung, Y. S.; Kim, M. H.; Song, T. K.; Kim, S. S. [Changwon National University, Changwon (Korea, Republic of); Choi, B. C. [Pukyung National University, Busan (Korea, Republic of); Choi, K. S. [Sunchon National University, Sunchon, Chonnam (Korea, Republic of)

    2010-01-15

    Alkali-metal-excess lead-free 0.93(K{sub 0.5}Na{sub 0.5}){sub (1+x)}NbO{sub 3}-0.07LiNbO{sub 3} (KNNL) piezoelectric ceramics were prepared by using a solid state reaction. The contents of both K and Na were simultaneously controlled to 4 mol% excess. From X-ray diffraction and temperature-dependent dielectric constant measurements, a polymorphic phase transition (PPT) between the tetragonal and orthorhombic phases was observed by changing the stoichiometry of x. With increasing (K+Na) content, the PPT temperature increased, but the Curie temperature decreased. The highest piezoelectric constant was 189 pC/N for x = 0.01, where the PPT temperature was around room temperature.

  13. Improved thermoelectric performance in polycrystalline p-type Bi2Te3 via an alkali metal salt hydrothermal nanocoating treatment approach

    Science.gov (United States)

    Ji, Xiaohua; He, Jian; Su, Zhe; Gothard, Nick; Tritt, Terry M.

    2008-08-01

    We report herein a proof-of-principle study of grain boundary engineering in the polycrystalline p-type Bi2Te3 system. Utilizing the recently developed hydrothermal nanocoating treatment technique, we fabricated an alkali-metal(s)-containing surface layer on the p-Bi2Te3 bulk grain, which in turn became part of the grain boundary upon hot pressing densification. Compared to the untreated bulk reference, the dimensionless figure of merit ZT has been improved by ˜30% in the Na-treated sample chiefly due to the reduced thermal conductivity, and ˜38% in the Rb-treated sample mainly owing to the improved power factor. The grain boundary phase provides a new avenue by which one can potentially decouple the otherwise inter-related electrical resistivity, Seebeck coefficient, and thermal conductivity within one thermoelectric material.

  14. The effects of correlation, relativity, exchange, channels coupling and polarization in scattering of electrons by alkali-metal atoms and alkali-like ions

    International Nuclear Information System (INIS)

    The present review briefly presents the growing experimental as well as theoretical interest in recent years in the effects of correlation, relativity, exchange, channels coupling and polarization on the high precision scattering of electron by alkali-metal atoms and alkali-like ions. Many high precision experiments have been performed which need very high accurate theoretical prediction for correct interpretation and identification of different physical effects involved. Several sophisticated theoretical techniques have been developed for inclusion of the above mentioned effects which play an extremely important role in order to obtain results of high accuracy for understanding experimental observation of high precision. At present, we do not have a comprehensive and practical atomic scattering theory which accounts for all these effects on an equal footing. Future challenges and directions, in reliable electron-atom scattering calculations, have been discussed and suggested. (author). 136 refs, 16 figs

  15. Dispersion coefficients for the interactions of the alkali-metal and alkaline-earth-metal ions and inert-gas atoms with a graphene layer

    Science.gov (United States)

    Kaur, Kiranpreet; Arora, Bindiya; Sahoo, B. K.

    2015-09-01

    Largely motivated by a number of applications, the van der Waals dispersion coefficients C3 of the alkali-metal ions Li+,Na+,K+, and Rb+, the alkaline-earth-metal ions Ca+,Sr+,Ba+, and Ra+, and the inert-gas atoms He, Ne, Ar, and Kr with a graphene layer are determined precisely within the framework of the Dirac model. For these calculations, we evaluate the dynamic polarizabilities of the above atomic systems very accurately by evaluating the transition matrix elements employing relativistic many-body methods and using the experimental values of the excitation energies. The dispersion coefficients are given as functions of the separation distance of an atomic system from the graphene layer and the ambiance temperature during the interactions. For easy extraction of these coefficients, we give a logistic fit to the functional forms of the dispersion coefficients in terms of the separation distances at room temperature.

  16. Partial Oxidation of Butane to Syngas over Nickel SupportedCatalysts Modified by Alkali Metal Oxide and Rare-Earth Metal Oxide

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The partial oxidation of butane (POB) to syngas over nickel supported catalysts was first investigated with a flow-reactor, TG and UVRRS. The NiO/g-Al2O3 is the most suitable for the POB among NiO/g-Al2O3, NiO/MgO and NiO/SiO2. And the reaction performance of the NiO/g-Al2O3 shows little difference from those of the nickel supported catalysts modified by alkali metal oxide and rare-earth metal oxide. However, modification with Li2O and La2O3 can suppress carbon-deposition of the NiO/g-Al2O3, which contains graphite-like species during the POB reaction.

  17. Design study of a 200 MW(e) alkali metal/steam binary power plant using a coal-fired fluidized bed furnace

    Energy Technology Data Exchange (ETDEWEB)

    Samuels, G.; Graves, R. L.; Lackey, M. E.; Tudor, J. J.; Zimmerman, G. P.

    1978-04-01

    The results of a study of 200 MW(e) alkali metal/steam binary power plant using a coal-fired fluidized bed furnace are described. Both cesium and potassium were evaluated for the topping cycle working fluid and cesium was selected. The fuel used was Illinois No. 6 coal, and limestone was used as the bed sorbent material. For the reference design, the furnace operated at atmospheric pressure and the cycle conditions for the power conversion system were 1500/sup 0/F to 900/sup 0/F for the topping cycle and 2400 psi 1000/sup 0/F to 1/sup 1///sub 2/ in. Hg for the steam system. Several variations of the plant were briefly evaluated. These variations included using a supercritical steam system and using a pressurized furnace. The principal conclusions of the study are as follows: a satisfactory design of an atmospheric pressure fluidized bed furnace binary power plant was evolved which uses a variation of the conventional binary cycle which permits utilizing the full potential of the alkali metal topping cycle; the net plant efficiency (coal to busbar) of the reference system was 44.6%; the net plant efficiency of a larger system with a 3500 psi 1000/sup 0/F steam system was 46.8%; an intermediate pressure turbocharged system with a furnace pressure of 4 atm (0.4 MPa) would have many advantages in comparison to the atmospheric pressure system, including a plant efficiency about one percentage point higher than the reference design, reduced limestone requirement and potential capital cost saving; and although cost estimates were not a part of the design study, a comparison of the design of this study to that of the Energy Conversion Alternative Study (ECAS) indicates plant costs 20 to 25% less than that of the final ECAS design.

  18. Light shift averaging in paraffin-coated alkali vapor cells

    CERN Document Server

    Zhivun, Elena; Sudyka, Julia; Pustelny, Szymon; Patton, Brian; Budker, Dmitry

    2015-01-01

    Light shifts are an important source of noise and systematics in optically pumped magnetometers. We demonstrate that the long spin coherence time in paraffin-coated cells leads to spatial averaging of the light shifts over the entire cell volume. This renders the averaged light shift independent, under certain approximations, of the light-intensity distribution within the sensor cell. These results and the underlying mechanism can be extended to other spatially varying phenomena in anti-relaxation-coated cells with long coherence times.

  19. High Pressure Chemical Vapor Deposition of Hydrogenated Amorphous Silicon Films and Solar Cells.

    Science.gov (United States)

    He, Rongrui; Day, Todd D; Sparks, Justin R; Sullivan, Nichole F; Badding, John V

    2016-07-01

    Thin films of hydrogenated amorphous silicon can be produced at MPa pressures from silane without the use of plasma at temperatures as low as 345 °C. High pressure chemical vapor deposition may open a new way to low cost deposition of amorphous silicon solar cells and other thin film structures over very large areas in very compact, simple reactors. PMID:27174318

  20. Laser pulse propagation in a meter scale rubidium vapor/plasma cell in AWAKE experiment

    OpenAIRE

    Joulaei, Atefeh; Moody, Joshua; Berti, Nicolas; Kasparian, Jérôme; Mirzanejhad, Saeed; Muggli, Patric

    2015-01-01

    We present the results of numerical studies of laser pulse propagating in a 3.5 cm Rb vapor cell in the linear dispersion regime by using a 1D model and a 2D code that has been modified for our special case. The 2D simulation finally aimed at finding laser beam parameters suitable to make the Rb vapor fully ionized to obtain a uniform, 10 m-long, at least 1 mm in radius plasma in the next step for the AWAKE experiment.

  1. Laser pulse propagation in a meter scale rubidium vapor/plasma cell in AWAKE experiment

    CERN Document Server

    Joulaei, Atefeh; Berti, Nicolas; Kasparian, Jerome; Mirzanejhad, Saeed; Muggli, Patric

    2016-01-01

    We present the results of numerical studies of laser pulse propagating in a 3.5 cm Rb vapor cell in the linear dispersion regime by using a 1D model and a 2D code that has been modified for our special case. The 2D simulation finally aimed at finding laser beam parameters suitable to make the Rb vapor fully ionized to obtain a uniform, 10 m-long, at least 1 mm in radius plasma in the next step for the AWAKE experiment.

  2. Laser pulse propagation in a meter scale rubidium vapor/plasma cell in AWAKE experiment

    Science.gov (United States)

    Joulaei, A.; Moody, J.; Berti, N.; Kasparian, J.; Mirzanejhad, S.; Muggli, P.

    2016-09-01

    We present the results of numerical studies of laser pulse propagating in a 3.5 cm Rb vapor cell in the linear dispersion regime by using a 1D model and a 2D code that has been modified for our special case. The 2D simulation finally aimed at finding laser beam parameters suitable to make the Rb vapor fully ionized to obtain a uniform, 10 m-long, at least 1 mm in radius plasma in the next step for the AWAKE experiment.

  3. Microfabricated cells for chip-scale atomic clock based on coherent population trapping: Fabrication and investigation

    Directory of Open Access Journals (Sweden)

    S.V. Ermak

    2015-03-01

    Full Text Available A universal method for fabrication of miniature cells for frequency standards and quantum magnetometers containing 87Rb atoms in the atmosphere of inert gas neon based on integrated technologies is considered. The results of experimental studies of coherent population trapping signals observed for a series of cells which provided recovery of vapors of an alkali metal from the rubidium dichromate salt with the help of laser radiation are presented. The coherent population trapping signals with a typical linewidth of 2–3 kHz and a signal-to-noise ratio of 1500 in the 1-Hz bandwidth were observed, which allows one to provide a relative frequency stability of atomic clock of 10−11 at 100 s.

  4. Oxidative Chemical Vapor Deposition of Neutral Hole Transporting Polymer for Enhanced Solar Cell Efficiency and Lifetime.

    Science.gov (United States)

    Jo, Won Jun; Nelson, Justin T; Chang, Sehoon; Bulović, Vladimir; Gradečak, Silvija; Strano, Michael S; Gleason, Karen K

    2016-08-01

    The concept of a neutral hole-transporting polymer is realized for the first time, by integrating patterned Cl(-) -doped poly(3,4-dimethoxythiophene) thin films into organic solar cells through a vacuum-based polymer vapor printing technique. Due to this novel polymer's neutrality, high transparency, good conductivity, and appropriate energy levels, the solar-cell efficiency and lifetime are significantly enhanced. PMID:27167214

  5. An Alkali-Vapor Cell with Metal Coated Windows for Efficient Application of an Electric Field

    CERN Document Server

    Sarkisyan, D; Guena, J; Lintz, M; Bouchiat, M A; Sarkisyan, David; Gu\\'{e}na, Jocelyne; Lintz, Michel; Bouchiat, Marie-Anne

    2005-01-01

    We describe the implementation of a cylindrical T-shaped alkali-vapor cell for laser spectroscopy in the presence of a longitudinal electric field. The two windows are used as two electrodes of the high-voltage assembly, which is made possible by a metallic coating which entirely covers the inner and outer sides of the windows except for a central area to let the laser beams in and out of the cell. This allows very efficient application of the electric field, up to 2 kV/cm in a rather dense superheated vapor, even when significant photoemission takes place at the windows during pulsed laser irradiation. The body of the cell is made of sapphire or alumina ceramic to prevent large currents resulting from surface conduction observed in cesiated glass cells. The technique used to attach the monocrystalline sapphire windows to the cell body causes minimal stress birefringence in the windows. In addition, reflection losses at the windows can be made very small. The vapor cell operates with no buffer gas and has no ...

  6. A vapor feed methanol microfluidic fuel cell with high fuel and energy efficiency

    International Nuclear Information System (INIS)

    Highlights: • A microfluidic fuel cell with a vapor feed anode is investigated. • Its advantages include simpler design, direct usage of methanol and better performance. • The prototype achieves a peak power density of 55.4 mW cm−2 under room temperature. • The energy efficiency of 9.4% is much higher than its liquid feed counterpart. - Abstract: In this paper, a prototype of methanol microfluidic fuel cell with vapor feed anode configuration is proposed to improve the fuel and energy efficiency of the conventional liquid feed methanol microfluidic fuel cells. Peak power density of 55.4 mW cm−2 can be achieved with this prototype under room temperature, which is 30% higher than its conventional liquid feed counterpart. Moreover, an energy efficiency of 9.4% is achieved, which is 27.5 times higher than its liquid feed counterpart. This superiority on both cell performance and energy efficiency is directly benefitted from its vapor feed anode configuration, which alleviates the fuel crossover, eliminates the fuel depletion boundary layer, and avoids the bulk anolyte wastage. The tradeoff between cell performance and fuel utilization for conventional liquid feed microfluidic fuel cells is also evaded

  7. Imaging Microwave and DC Magnetic Fields in a Vapor-Cell Rb Atomic Clock

    CERN Document Server

    Affolderbach, Christoph; Bandi, Thejesh; Horsley, Andrew; Treutlein, Philipp; Mileti, Gaetano

    2015-01-01

    We report on the experimental measurement of the DC and microwave magnetic field distributions inside a recently-developed compact magnetron-type microwave cavity, mounted inside the physics package of a high-performance vapor-cell atomic frequency standard. Images of the microwave field distribution with sub-100 $\\mu$m lateral spatial resolution are obtained by pulsed optical-microwave Rabi measurements, using the Rb atoms inside the cell as field probes and detecting with a CCD camera. Asymmetries observed in the microwave field images can be attributed to the precise practical realization of the cavity and the Rb vapor cell. Similar spatially-resolved images of the DC magnetic field distribution are obtained by Ramsey-type measurements. The T2 relaxation time in the Rb vapor cell is found to be position dependent, and correlates with the gradient of the DC magnetic field. The presented method is highly useful for experimental in-situ characterization of DC magnetic fields and resonant microwave structures,...

  8. Measurement of background gas in paraffin-coated alkali vapor cells

    CERN Document Server

    Sekiguchi, Naota

    2015-01-01

    We measured the rate of velocity-changing collisions (VCCs) between alkali atoms and background gas in buffer-gas-free anti-spin-relaxation-coated cells. The average VCC rate in paraffin-coated rubidium vapor cells prepared in this work was $1 \\times 10^{6}$ s$^{-1}$, which corresponds to $\\sim$1 mm in the mean free path of rubidium atoms. This short mean free path indicates that alkali atoms do not travel freely between the cell walls. In addition, we found that a heating process known as "ripening" increases the VCC rate, and also confirmed that ripening improves the anti-relaxation performance of the coatings.

  9. Structural changes of polyacids initiated by their neutralization with various alkali metal hydroxides. Diffusion studies in poly(acrylic acid)s.

    Science.gov (United States)

    Masiak, Michal; Hyk, Wojciech; Stojek, Zbigniew; Ciszkowska, Malgorzata

    2007-09-27

    The changes in the three-dimensional structure of the poly(acrylic acid), PAA, induced by incorporation of various alkali-metal counterions have been evaluated by studying diffusion of an uncharged probe (1,1'-ferrocenedimethanol) in the polymeric media. The studies are supported by the measurements of conductivity and viscosity of the polymeric media. Solutions of linear PAA of four different sizes (molecular weights: 450,000, 750,000, 1,250,000, 4,000,000) were neutralized with hydroxides of alkali metals of group 1 of the periodic table (Li, Na, K, Rb, Cs) to the desired neutralization degree. The transport properties of the obtained polyacrylates were monitored by measuring the changes in the probe diffusion coefficient during the titration of the polyacids. The probe diffusivity was determined from the steady-state current of the probe voltammetric oxidation at disk microelectrodes. Diffusivity of the probe increases with the increase in the degree of neutralization and with the increase in viscosity. It reaches the maximum value at about 60-80% of the polyacid neutralization. The way the probe diffusion coefficients change is similar in all polyacid solutions and gels. The increase in the size of a metal cation causes, in general, an enhancement in the transport of probe molecules. The biggest differences in the probe diffusivities are between lithium and cesium polyacrylates. The differences between the results obtained for cesium and rubidium are not statistically significant due to lack of good precision of the voltammetric measurements. The measurements of the electric conductivity of polyacrylates and the theoretical predictions supplemented the picture of electrostatic interactions between the polyanionic chains and the metal cations of increasing size. In all instances of the PAAs, the viscosity of the solutions rapidly increases in the 0-60% range of neutralization and then becomes constant in the 60-100% region. With the exception of the shortest

  10. Radio-frequency Electrometry Using Rydberg Atoms in Vapor Cells: Towards the Shot Noise Limit

    Science.gov (United States)

    Kumar, Santosh; Fan, Haoquan; Jahangiri, Akbar; Kuebler, Harald; Shaffer, James P.; 5. Physikalisches Institut, Universitat Stuttgart, Germany Collaboration

    2016-05-01

    Rydberg atoms are a promising candidate for radio frequency (RF) electric field sensing. Our method uses electromagnetically induced transparency with Rydberg atoms in vapor cells to read out the effect that the RF electric field has on the Rydberg atoms. The method has the potential for high sensitivity (pV cm-1 Hz- 1 / 2) and can be self-calibrated. Some of the main factors limiting the sensitivity of RF electric field sensing from reaching the shot noise limit are the residual Doppler effect and the sensitivity of the optical read-out using the probe laser. We present progress on overcoming the residual Doppler effect by using a new multi-photon scheme and reaching the shot noise detection limit using frequency modulated spectroscopy. Our experiments also show promise for studying quantum optical effects such as superradiance in vapor cells using Rydberg atoms. This work is supported by DARPA, ARO, and NRO.

  11. Fabrication of efficient planar perovskite solar cells using a one-step chemical vapor deposition method

    OpenAIRE

    Mohammad Mahdi Tavakoli; Leilei Gu; Yuan Gao; Claas Reckmeier; Jin He; Rogach, Andrey L; Yan Yao; Zhiyong Fan

    2015-01-01

    Organometallic trihalide perovskites are promising materials for photovoltaic applications, which have demonstrated a rapid rise in photovoltaic performance in a short period of time. We report a facile one-step method to fabricate planar heterojunction perovskite solar cells by chemical vapor deposition (CVD), with a solar power conversion efficiency of up to 11.1%. We performed a systematic optimization of CVD parameters such as temperature and growth time to obtain high quality films of CH...

  12. Diode laser spectroscopy of NaD, KD, RbD, and CsD: determination of the mass independent parameters and mass scaling coefficients of the alkali metal hydrides

    International Nuclear Information System (INIS)

    The infrared spectrum of the monodeuterides of the alkali metals, sodium, potassium, rubidium, and cesium have been measured with a nominal accuracy of ±0.001 cm-1 using a diode laser spectrometer. Spectral lines of both the fundamental and the first hot band were observed for all the deuterides except RbD where only the fundamental was measured. The accuracy of previously published data on KH was also improved. Combination of these new data with similar results obtained previously for the equivalent monohydrides allowed the determination of a set of mass-independent parameters and mass-scaling coefficients for the hydrides of all of the alkali metals. This has allowed the relative magnitudes of the parameters to be compared for the first time. The results indicate that non-adiabatic effects are most prevalent in CsH. (orig.)

  13. Ion chromatography with the indirect ultraviolet detection of alkali metal ions and ammonium using imidazolium ionic liquid as ultraviolet absorption reagent and eluent.

    Science.gov (United States)

    Liu, Yong-Qiang; Yu, Hong

    2016-08-01

    Indirect ultraviolet detection was conducted in ultraviolet-absorption-agent-added mobile phase to complete the detection of the absence of ultraviolet absorption functional group in analytes. Compared with precolumn derivatization or postcolumn derivatization, this method can be widely used, has the advantages of simple operation and good linear relationship. Chromatographic separation of Li(+) , Na(+) , K(+) , and NH4 (+) was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid/organic solvent as the mobile phase, in which imidazolium ionic liquids acted as ultraviolet absorption reagent and eluting agent. The retention behaviors of four kinds of cations are discussed, and the mechanism of separation and detection are described. The main factors influencing the separation and detection were the background ultraviolet absorption reagent and the concentration of hydrogen ion in the ion chromatography-indirect ultraviolet detection. The successful separation and detection of Li(+) , Na(+) , K(+) , and NH4 (+) within 13 min was achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.02, 0.11, 0.30, and 0.06 mg/L, respectively. A new separation and analysis method of alkali metal ions and ammonium by ion chromatography with indirect ultraviolet detection method was developed, and the application range of ionic liquid was expanded.

  14. Dipole Polarizability of Alkali-Metal (Na, K, Rb) - Alkaline-Earth-Metal (Ca,Sr) Polar molecules - Prospects of Alignment

    CERN Document Server

    Gopakumar, Geetha; Hada, Masahiko; Kajita, Masatoshi

    2014-01-01

    Electronic open-shell ground-state properties of selected alkali-metal (AM) - alkaline-earth-metal (AEM) polar molecules are investigated. We determine potential energy curves of the 2{\\Sigma}+ ground state at the coupled-cluster singles and doubles with partial triples (CCSD(T)) level of electron correlation. Calculated spectroscopic constants for the isotopes (23Na, 39K, 85Rb) - (40Ca, 88Sr) are compared with available theoretical and experimental results. The variation of the permanent dipole moment (PDM), average dipole polarizability, and polarizability anisotropy with internuclear distance is determined using finite-field perturbation theory at the CCSD(T) level. Owing to moderate PDM (KCa: 1.67 D, RbCa: 1.75 D, KSr: 1.27 D, RbSr: 1.41 D) and large polarizability anisotropy (KCa: 566 a.u., RbCa: 604 a.u., KSr: 574 a.u., RbSr: 615 a.u.), KCa, RbCa, KSr, and RbSr are potential candidates for alignment and orientation in combined intense laser and external static electric fields.

  15. Theoretical study on the ground state of the polar alkali-metal-barium molecules: potential energy curve and permanent dipole moment.

    Science.gov (United States)

    Gou, Dezhi; Kuang, Xiaoyu; Gao, Yufeng; Huo, Dongming

    2015-01-21

    In this paper, we systematically investigate the electronic structure for the (2)Σ(+) ground state of the polar alkali-metal-alkaline-earth-metal molecules BaAlk (Alk = Li, Na, K, Rb, and Cs). Potential energy curves and permanent dipole moments (PDMs) are determined using power quantum chemistry complete active space self-consistent field and multi-reference configuration interaction methods. Basic spectroscopic constants are derived from ro-vibrational bound state calculation. From the calculations, it is shown that BaK, BaRb, and BaCs molecules have moderate values of PDM at the equilibrium bond distance (BaK:1.62 D, BaRb:3.32 D, and BaCs:4.02 D). Besides, the equilibrium bond length (4.93 Å and 5.19 Å) and dissociation energy (0.1825 eV and 0.1817 eV) for the BaRb and BaCs are also obtained. PMID:25612710

  16. Theoretical study on the ground state of the polar alkali-metal-barium molecules: Potential energy curve and permanent dipole moment

    Energy Technology Data Exchange (ETDEWEB)

    Gou, Dezhi; Kuang, Xiaoyu, E-mail: scu-kuang@163.com; Gao, Yufeng; Huo, Dongming [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China)

    2015-01-21

    In this paper, we systematically investigate the electronic structure for the {sup 2}Σ{sup +} ground state of the polar alkali-metal-alkaline-earth-metal molecules BaAlk (Alk = Li, Na, K, Rb, and Cs). Potential energy curves and permanent dipole moments (PDMs) are determined using power quantum chemistry complete active space self-consistent field and multi-reference configuration interaction methods. Basic spectroscopic constants are derived from ro-vibrational bound state calculation. From the calculations, it is shown that BaK, BaRb, and BaCs molecules have moderate values of PDM at the equilibrium bond distance (BaK:1.62 D, BaRb:3.32 D, and BaCs:4.02 D). Besides, the equilibrium bond length (4.93 Å and 5.19 Å) and dissociation energy (0.1825 eV and 0.1817 eV) for the BaRb and BaCs are also obtained.

  17. 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.

  18. Ab initio properties of the ground-state polar and paramagnetic europium-alkali-metal-atom and europium-alkaline-earth-metal-atom molecules

    CERN Document Server

    Tomza, Michał

    2014-01-01

    The properties of the electronic ground state of the polar and paramagnetic europium-$S$-state-atom molecules have been investigated. Ab initio techniques have been applied to compute the potential energy curves for the europium-alkali-metal-atom, Eu$X$ ($X$=Li, Na, K, Rb, Cs), europium-alkaline-earth-metal-atom, Eu$Y$ ($Y$=Be, Mg, Ca, Sr, Ba), and europium-ytterbium, EuYb, molecules in the Born-Oppenheimer approximation for the high-spin electronic ground state. The spin restricted open-shell coupled cluster method restricted to single, double, and noniterative triple excitations, RCCSD(T), was employed and the scalar relativistic effects within the small-core energy-consistent pseudopotentials were included. The permanent electric dipole moments and static electric dipole polarizabilities were computed. The leading long-range coefficients describing the dispersion interaction between atoms at large internuclear distances $C_6$ are also reported. The EuK, EuRb, and EuCs molecules are examples of species poss...

  19. The Effect of Mercury Vapor and the Role of Green Tea Extract on Brain Cells

    Directory of Open Access Journals (Sweden)

    Dhona Afriza

    2013-09-01

    Full Text Available Mercury is a wellknown toxic metal that is capable to induce free radical-induced oxidative stress. It can cause human disease including brain disorders. Objective: To identify the effect of mercury vapor inhalation on brain cells and the role of green tea extract (Camellia sinensis as antioxidant on the brain cells exposed to mercury. Methods: Fourty-eight male Mus musculus were divided into 8 groups, which were given treatment for 3 and 6 weeks. Group A did not receive any treatment and served as a negative control. Group B was a positive control exposed to Mercury. Group C was exposed to Mercury and treated with 26μg/g green tea extract. Group D was exposed to mercury and treated with 52μg/g green tea extract. All animals in the Group B, C, D were exposed to mercury through inhalation for 4 hours daily. The effect of mercury on the brain cells were examined histopathologically. Results: The numbers of necrotic cells counted in the green tea-treated mice group were significantly lower than those untreated group (p<0,05. Conclusion: Mercury vapor inhalation may cause necrosis on brain cells. Administration of green tea extract as an antioxidant reduced the amount of mercury-induced necrotic brain cells in mice.DOI: 10.14693/jdi.v20i2.151

  20. Vapor Delivery Systems for the Study of the Effects of Reformate Gas Impurities in HT-PEM Fuel Cells

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Kær, Søren Knudsen; Andreasen, Søren Juhl

    2011-01-01

    , impurities in the reformate gas produced from methanol steam reforming can affect the performance and durability of fuel cells. In this paper different vapor delivery systems, intended to assist in the study of the effects of some of the impurities, are described and compared with each other. A system based...... on a pump and electrically heated evaporator was found to be more suitable for the typical flow rates involved in the anode feed of an H3PO4/PBI based HT-PEMFC unit cell assembly. Test stations composed of vapor delivery systems and mass flow controllers for testing the effects of methanol slip, water vapor...

  1. The Effect of Mercury Vapor and the Role of Green Tea Extract on Brain Cells

    OpenAIRE

    Dhona Afriza

    2013-01-01

    Mercury is a wellknown toxic metal that is capable to induce free radical-induced oxidative stress. It can cause human disease including brain disorders. Objective: To identify the effect of mercury vapor inhalation on brain cells and the role of green tea extract (Camellia sinensis) as antioxidant on the brain cells exposed to mercury. Methods: Fourty-eight male Mus musculus were divided into 8 groups, which were given treatment for 3 and 6 weeks. Group A did not receive any treatment and se...

  2. Novel photochemical vapor deposition reactor for amorphous silicon solar cell deposition

    Science.gov (United States)

    Rocheleau, Richard E.; Hegedus, Steven S.; Buchanan, Wayne A.; Jackson, Scott C.

    1987-07-01

    A novel photochemical vapor deposition (photo-CVD) reactor having a flexible ultraviolet-transparent Teflon curtain and a secondary gas flow to eliminate deposition on the window has been used to deposit amorphous silicon films and p-i-n solar cells. The background levels of atmospheric contaminants (H2O, CO2, N2) depend strongly on the vacuum procedures but not on the presence of a Teflon curtain in the reactor. Intrinsic films with a midgap density of states of 3×1015 eV-1 cm-3 and all-photo-CVD pin solar cells with efficiencies of 8.5% have been deposited.

  3. Uranium Metalla-Allenes with Carbene Imido R2 C=U(IV) =NR' Units (R=Ph2 PNSiMe3 ; R'=CPh3 ): Alkali-Metal-Mediated Push-Pull Effects with an Amido Auxiliary.

    Science.gov (United States)

    Lu, Erli; Tuna, Floriana; Lewis, William; Kaltsoyannis, Nikolas; Liddle, Stephen T

    2016-08-01

    We report uranium(IV)-carbene-imido-amide metalla-allene complexes [U(BIPM(TMS) )(NCPh3 )(NHCPh3 )(M)] (BIPM(TMS) =C(PPh2 NSiMe3 )2 ; M=Li or K) that can be described as R2 C=U=NR' push-pull metalla-allene units, as organometallic counterparts of the well-known push-pull organic allenes. The solid-state structures reveal that the R2 C=U=NR' units adopt highly unusual cis-arrangements, which are also reproduced by gas-phase theoretical studies conducted without the alkali metals to remove their potential structure-directing roles. Computational studies confirm the double-bond nature of the U=NR' and U=CR2 interactions, the latter increasingly attenuated by potassium then lithium when compared to the hypothetical alkali-metal-free anion. Combined experimental and theoretical data show that the push-pull effect induced by the alkali metal cations and amide auxiliary gives a fundamental and tunable structural influence over the C=U(IV) =N units. PMID:27403746

  4. Analysis on Alkali Metal Migration Law in Process of Eucalyptus Branches Direct Combustion%桉树枝直燃利用过程中碱金属迁移规律分析

    Institute of Scientific and Technical Information of China (English)

    韦威; 廖艳芬; 陈拓; 马晓茜; 杨云金; 余勇强

    2014-01-01

    For knowing alkali metal migration law in eucalyptus branches burned in some biomass power plant,this paper studies it by combustion experiment.The experimental sample is eucalyptus branch particle with grain size of 1 80μm which is used for repeat combustion experiment in pipe burner in order to get residual samples under different temperatures and with different combustion time.By proximate analysis on residual samples,it is able to get combustion laws of volatiles and fixed carbon.The experimental result shows that volatility of alkali metal in eucalyptus branches is very strong and there is 87%potassium released into gas phase in process of high temperature burning.Meanwhile,precipitation of alkali metal is speeding up with increase of temperature and precipitation volume dose is increasing with temperature and stop time.In addition,tak-ing kaolin as additive,it conducts quantitative analysis on its impact on retention rate of alkali metal in ash.The analysis re-sult indicates that kaolin has very good retention role for alkali metal in eucalyptus branches and retention effect of 5% kao-lin is the best.%为了解某生物质电厂燃用的桉树枝的碱金属迁移规律,对其进行了燃烧实验研究。实验样品为粒径180μm的桉树枝颗粒,在管式燃烧器中进行燃烧重复实验,获得不同温度和燃烧时间下的残留物样品,然后对残留物进行工业分析,获得挥发分、固定碳的燃烧规律;实验结果表明桉树枝碱金属挥发性很强,高温燃尽时有87%的钾释放进入气相,碱金属的析出随温度的增高而加快,析出总量也随温度和停留时间而增加。另外,以高岭土作为添加剂,定量分析了其对桉树枝碱金属在灰渣中的固留率的影响,分析结果表明高岭土对桉树枝的碱金属有很好固留作用,5%的高岭土添加量固留效果最佳。

  5. Effects of viscosity on endothelial cell damage under acoustic droplet vaporization

    Science.gov (United States)

    Seda, Robinson; Singh, Rahul; Li, David; Pitre, John; Putnam, Andrew; Fowlkes, J. Brian; Bull, Joseph

    2014-11-01

    Acoustic droplet vaporization (ADV) is a process by which stabilized superheated microdroplets are able to undergo phase transition with the aid of focused ultrasound. Gas bubbles resulting from ADV can provide local occlusion of the blood vessels supplying diseased tissue, such as tumors. The ADV process can also induce bioeffects that increase vessel permeability, which is beneficial for localized drug delivery. Previous in vitro studies have demonstrated that vaporization at the endothelial layer will affect cell attachment and viability. Several hypotheses have been proposed to elucidate the mechanism of damage including the generation of normal and shear stresses during bubble expansion. A single 3.5 MHz ultrasound pulse consisting of 8 cycles (~2.3 μs) and a 6 MPa peak rarefactional pressure was used to induce ADV on endothelial cells in media of different viscosities. Carboxylmethyl cellulose was added to the cell media to increase the viscosity up to 300 cP to and aid in the reduction of stresses during bubble expansion. The likelihood of cell damage was decreased when compared to our control (~1 cP), but it was still present in some cases indicating that the mechanism of damage does not depend entirely on viscous stresses associated with bubble expansion. This work was supported by NIH Grant R01EB006476.

  6. Investigating the Effect of Pyridine Vapor Treatment on Perovskite Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Alison [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-20

    Perovskite photovoltaics have recently come to prominence as a viable alternative to crystalline silicon based solar cells. In an effort to create consistent and high-quality films, we studied the effect of various annealing conditions as well as the effect of pyridine vapor treatment on mixed halide methylammonium lead perovskite films. Of six conditions tested, we found that annealing at 100°C for 90 minutes followed by 120°C for 15 minutes resulted in the purest perovskite. Perovskite films made using that condition were treated with pyridine for various amounts of time, and the effects on perovskite microstructure were studied using x-ray diffraction, UV-Vis spectroscopy, and time-resolved photoluminescence lifetime analysis (TRPL). A previous study found that pyridine vapor caused perovskite films to have higher photoluminescence intensity and become more homogenous. In this study we found that the effects of pyridine are more complex: while films appeared to become more homogenous, a decrease in bulk photoluminescence lifetime was observed. In addition, the perovskite bandgap appeared to decrease with increased pyridine treatment time. Finally, X-ray diffraction showed that pyridine vapor treatment increased the perovskite (110) peak intensity but also often gave rise to new unidentified peaks, suggesting the formation of a foreign species. It was observed that the intensity of this unknown species had an inverse correlation with the increase in perovskite peak intensity, and also seemed to be correlated with the decrease in TRPL lifetime.

  7. Investigating the Effect of Pyridine Vapor Treatment on Perovskite Solar Cells - Oral Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Alison J. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-25

    Perovskite photovoltaics have recently come to prominence as a viable alternative to crystalline silicon based solar cells. In an effort to create consistent and high-quality films, we studied the effect of various annealing conditions as well as the effect of pyridine vapor treatment on mixed halide methylammonium lead perovskite films. Of six conditions tested, we found that annealing at 100 degree Celsius for 90 minutes followed by 120 degree Celsius for 15 minutes resulted in the purest perovskite. Perovskite films made using that condition were treated with pyridine for various amounts of time, and the effects on perovskite microstructure were studied using x-ray diffraction, UV-Vis spectroscopy, and time-resolved photoluminescence lifetime analysis (TRPL). A previous study found that pyridine vapor caused perovskite films to have higher photoluminescence intensity and become more homogenous. In this study we found that the effects of pyridine are more complex: while films appeared to become more homogenous, a decrease in bulkphotoluminescence lifetime was observed. In addition, the perovskite bandgap appeared to decrease with increased pyridine treatment time. Finally, X-ray diffraction showed that pyridine vapor treatment increased the perovskite (110) peak intensity but also often gave rise to new unidentified peaks, suggesting the formation of a foreign species. It was observed that the intensity of this unknown species had an inverse correlation with the increase in perovskite peak intensity, and also seemed to be correlated with the decrease in TRPL lifetime.

  8. Perforated hollow core waveguides for Alkali Vapor-cells and Slow Light Devices

    Science.gov (United States)

    Giraud-Carrier, Matthieu C.

    The focus of this work is the integration of alkali vapor atomic vapor cells into common silicon wafer microfabrication processes. Such integrated platforms enable the study of quantum coherence effects such as electromagnetically induced transparency, which can in turn be used to demonstrate slow light. Slow and stopped light devices have applications in the optical communications and quantum computing fields. This project uses hollow core anti-resonant reflecting optical waveguides (ARROWs) to build such slow light devices. An explanation of light-matter interactions and the physics of slow light is first provided, as well as a detailed overview of the fabrication process. Following the discovery of a vapor transport issue, a custom capillary-based testing platform is developed to quantify the effect of confinement, temperature, and wall coatings on rubidium transport. A mathematical model is derived from the experimental results and predicts long transport times. A new design methodology is presented that addresses the transport problem by increasing the number of rubidium entry points. This design also improves chip durability and decreases environmental susceptibility through the use of a single copper reservoir and buried channel waveguides (BCWs). New chips are successfully fabricated, loaded, and monitored for rubidium spectra. Absorption is observed in several chips and absorption peaks depths in excess of 10% are reported. The chip lifetime remains comparable to previous designs. This new design can be expanded to a multi-core platform suitable for slow and stopped light experimentation. Keywords: Matthieu Giraud-Carrier, Aaron Hawkins, microfabrication, spectroscopy, slow light, stopped light, EIT, rubidium, diffusion, vapor transport, microfabrication, ARROW, light-matter interactions, waveguide.

  9. Alkali metal ions transfer across a water/1,2-dichloroethane interface facilitated by a novel monoaza-B15C5 derivative

    Energy Technology Data Exchange (ETDEWEB)

    Zhan Dongping; Yuan Yi; Xiao Yanjing; Wu Bingliang; Shao Yuanhua

    2002-10-30

    In this paper, a novel monoaza-B15C5 derivative, N-(2-tosylamino)-isopentyl-monoaza-15-crown-5 (L), is used as an ionophore to facilitate alkali metal cations transfer across a water/1,2-dichloroethane (W/DCE) interface. Well-defined voltammetric behaviors are observed at the polarized W/DCE interfaces supported at micro- and nano-pipets except Cs{sup +}. The diffusion coefficient of this ionophore in the DCE phase is calculated to be equal to (3.3{+-}0.2)x10{sup -6} cm{sup 2} s{sup -1}. The experimental results indicate that a 1:1 (metal:ionophore) complex is formed at the interface with a TIC/TID mechanism. The selectivity of this ionophore towards alkali ions follows the sequence Na{sup +}>Li{sup +}>K{sup +}>Rb{sup +}>Cs{sup +}. The logarithm of the association constants (log {beta}{sub 1}{sup o}) of the LiL{sup +}, NaL{sup +}, KL{sup +} and RbL{sup +} complexes in the DCE phase are calculated to be 10.6, 11.6, 9.0 and 7.1, respectively. The kinetic parameters are determined by steady-state voltammograms using nanopipets. The standard rate constants (k{sup 0}) for Li{sup +}, Na{sup +}, K{sup +} and Rb{sup +} transfers facilitated by L are 0.54{+-}0.05, 0.63{+-}0.09, 0.51{+-}0.04 and 0.46{+-}0.06 cm s{sup -1}, respectively. The pH values of aqueous solution have little effect on the electrochemical behaviors of these facilitated processes. The results predicate that this new type of ionophore might be useful to fabricate electrochemical sensor of sodium ion.

  10. Thin film cadmium telluride solar cells by two chemical vapor deposition techniques

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.L.

    1988-01-15

    Cadmium telluride (CdTe) has long been recognized as a promising thin film photovoltaic material. In this work, polycrystalline p-CdTe films have been deposited by two chemical vapor deposition techniques, namely the combination of vapors of elements (CVE) and close-spaced sublimation (CSS). The CVE technique is more flexible in controlling the composition of deposited films while the CSS technique can provide very high deposition rates. The resistivity of p-CdTe films deposited by the CVE and CSS techniques can be controlled by intrinsic (cadmium vacancies) or extrinsic (arsenic or antimony) doping, and the lowest resistivity obtainable is about 200 ..cap omega.. cm. Both front-wall (CdTe/TCS/glass) and back-wall (TCS/CdTe/substrate) cells have been prepared. The back-wall cells are less efficient because of the high and irreproducible p-CdTe-substrate interface resistance. The CSS technique is superior to the CVE technique because of its simplicity and high deposition rates; however, the cleaning of the substrate in situ is more difficult. The interface cleanliness is an important factor determining the electrical and photovoltaic characteristics of the heterojunction. Heterojunction CdS/CdTe solar cells of area 1 cm/sup 2/ with conversion efficiencies higher than 10% have been prepared and junction properties characterized.

  11. Widefield Microwave Imaging in Alkali Vapor Cells with sub-100 um Resolution

    CERN Document Server

    Horsley, Andrew; Treutlein, Philipp

    2015-01-01

    We report on widefield microwave vector field imaging with sub um resolution using a microfabricated alkali vapor cell. The setup can additionally image dc magnetic fields, and can be configured to image microwave electric fields. Our camera-based widefield imaging system records 2D images with a 6x6 mm2 field of view at a rate of 10 Hz. It provides up to 50 um spatial resolution, and allows imaging of fields as close as 150 um above structures, through the use of thin external cell walls. This is crucial in allowing us to take practical advantage of the high spatial resolution, as feature sizes in near-fields are on the order of the distance from their source, and represents an order of magnitude improvement in surface-feature resolution compared to previous vapor cell experiments. We present microwave and dc magnetic field images above a selection of devices, demonstrating a microwave sensitivity of 1.4 uT/sqrt-Hz per 50x50x140 um3 voxel, at present limited by the speed of our camera system. Since we image ...

  12. Homojunction GaAs solar cells grown by close space vapor transport

    Energy Technology Data Exchange (ETDEWEB)

    Boucher, Jason W. [University of Oregon; Ritenour, Andrew J. [University of Oregon; Greenaway, Ann L. [University of Oregon; Aloni, Shaul [Lawrence Berkeley National Laboratory; Boettcher, Shannon W. [University of Oregon

    2014-06-08

    We report on the first pn junction solar cells grown by homoepitaxy of GaAs using close space vapor transport (CSVT). Cells were grown both on commercial wafer substrates and on a CSVT absorber film, and had efficiencies reaching 8.1%, open circuit voltages reaching 909 mV, and internal quantum efficiency of 90%. The performance of these cells is partly limited by the electron diffusion lengths in the wafer substrates, as evidenced by the improved peak internal quantum efficiency in devices fabricated on a CSVT absorber film. Unoptimized highly-doped n-type emitters also limit the photocurrent, indicating that thinner emitters with reduced doping, and ultimately wider band gap window or surface passivation layers, are required to increase the efficiency.

  13. Fabrication of CdTe solar cells by laser-driven physical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Compaan, A.; Bhat, A.; Tabory, C.; Liu, S.; Nguyen, M.; Aydinli, A.; Tsien, L.H.; Bohn, R.G. (Toledo Univ., OH (USA). Dept. of Physics and Astronomy)

    1991-05-01

    Polycrystalline cadmium sulfide-cadmium telluride heterojunction solar cells were fabricated for the first time using a laser-driven physical vapor deposition method. An XeCl excimer laser was used to deposit both of the II-VI semiconductor layers in a single vacuum chamber from pressed powder targets. Results are presented from optical absorption. Raman scattering, X-ray diffraction, and electrical characterization of the films. Solar cells were fabricated by deposition onto SnO{sub 2}-coated glass with top contacts produced by gold evaporation. Device performance was evaluated from the spectral quantum efficiency and current-voltage measurements in the dark and with air mass 1.5 solar illumination. (orig.).

  14. Investigating the Effect of Water Vapor and Residual Methanol on the Anode of High Temperature PEM Fuel Cell

    DEFF Research Database (Denmark)

    Thomas, Sobi; Araya, Samuel Simon; Kær, Søren Knudsen;

    The objective is to understand the effect of methanol and water vapor separately on a high temperature PEM fuel cell. An investigation was performed with different anode fuel compositions and results in terms of performance and impedance analyzed. During the initial 1000 h, cell was tested with......, which suggest an improvement of total cell resistance also supported by the impedance comparison. There is no or minimal variation in performance with the introduction of 1 % methanol along with water vapor in the anode feed at 0.2 A cm-2 and 0.6A cm-2 ....... pure hydrogen under varying current densities of 0.2 A cm-2 and 0.6 A cm-2, followed by hydrogen mixed with 15 % water vapor and then with 1 % methanol. The degradation rates at two current densities 0.2 A cm-2 and 0.6 A cm-2 were analyzed and discussed. The degradation at higher current density is...

  15. Evaluation of E-Cigarette Liquid Vapor and Mainstream Cigarette Smoke after Direct Exposure of Primary Human Bronchial Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Stefanie Scheffler

    2015-04-01

    Full Text Available E-cigarettes are emerging products, often described as “reduced-risk” nicotine products or alternatives to combustible cigarettes. Many smokers switch to e-cigarettes to quit or significantly reduce smoking. However, no regulations for e-cigarettes are currently into force, so that the quality and safety of e-liquids is not necessarily guaranteed. We exposed primary human bronchial epithelial cells of two different donors to vapor of e-cigarette liquid with or without nicotine, vapor of the carrier substances propylene glycol and glycerol as well as to mainstream smoke of K3R4F research cigarettes. The exposure was done in a CULTEX® RFS compact  module, allowing the exposure of the cells at the air-liquid interface. 24 h post-exposure, cell viability and oxidative stress levels in the cells were analyzed. We found toxicological effects of e-cigarette vapor and the pure carrier substances, whereas the nicotine concentration did not have an effect on the cell viability. The viability of mainstream smoke cigarette exposed cells was 4.5–8 times lower and the oxidative stress levels 4.5–5 times higher than those of e-cigarette vapor exposed cells, depending on the donor. Our experimental setup delivered reproducible data and thus provides the opportunity for routine testing of e-cigarette liquids to ensure safety and quality for the user.

  16. New hypodiphosphates of the alkali metals: Synthesis, crystal structure and vibrational spectra of the hypodiphosphates(IV) M{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] (M=Rb and Cs)

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Peng [Institut fuer Anorganische und Analytische Chemie der TU Clausthal, Paul-Ernst-Strasse 4, D-38678 Clausthal-Zellerfeld (Germany); Wiegand, Thomas; Eckert, Hellmut [Institut fuer Physikalische Chemie and Graduate School of Chemistry, Westfaelische Wilhelms-Universitaet Muenster, Corrensstr. 28/30, D-48149 Muenster (Germany); Gjikaj, Mimoza, E-mail: mimoza.gjikaj@tu-clausthal.de [Institut fuer Anorganische und Analytische Chemie der TU Clausthal, Paul-Ernst-Strasse 4, D-38678 Clausthal-Zellerfeld (Germany)

    2012-10-15

    The new hypodiphosphates(IV) Rb{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] (1) and Cs{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] (2) were synthesized by soft chemistry reactions from aqueous solutions of hypophosphoric acid and the corresponding heavy alkali-metal carbonates. Their crystal structures were determined by single crystal X-ray diffraction. Both compounds crystallize isotypic in the triclinic space group P-1 with one formula unit in the unit cell. The structures are built up by discrete (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) units in staggered conformation for the P{sub 2}O{sub 6} skeleton and the corresponding alkali-metal cations. In the (H{sub 2}P{sub 2}O{sub 6}){sup 2-} ion the hydrogen atoms are in a 'trans-trans' conformation. O{center_dot}H-O hydrogen bonds between the (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) groups consolidate the structures into a three-dimensional network. The FT-Raman and {sup 31}P and {sup 1}H and MAS NMR spectra of the title compounds have been recorded and interpreted, especially with respect to their assignment to the (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) groups. Thermogravimetric data of 2 have been interpreted in terms of a thermal decomposition model. - Graphical Abstract: The layered compounds Rb{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] and Cs{sub 2}[(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})] have been synthesized and investigated. Both crystallize isotypic. The structures are built up by discrete (H{sub 2}P{sub 2}O{sub 6}){sup 2-} and (H{sub 4}P{sub 2}O{sub 6}) units and the corresponding alkali-metal cations. Highlights: Black-Right-Pointing-Pointer Synthesis and single-crystal structure of new alkali hypodiphosphates. Black-Right-Pointing-Pointer Structures are characterized by [(H{sub 2}P{sub 2}O{sub 6})(H{sub 4}P{sub 2}O{sub 6})]{sup 2-} units and M

  17. Chromium vaporization from mechanically deformed pre-coated interconnects in Solid Oxide Fuel Cells

    Science.gov (United States)

    Falk-Windisch, Hannes; Sattari, Mohammad; Svensson, Jan-Erik; Froitzheim, Jan

    2015-11-01

    Cathode poisoning, associated with Cr evaporation from interconnect material, is one of the most important degradation mechanisms in Solid Oxide Fuel Cells when Cr2O3-forming steels are used as the interconnect material. Coating these steels with a thin Co layer has proven to decrease Cr vaporization. To reduce production costs, it is suggested that thin metallic PVD coatings be applied to each steel strip before pressing the material into interconnect shape. This process would enable high volume production without the need for an extra post-coating step. However, when the pre-coated material is mechanically deformed, cracks may form and lower the quality of the coating. In the present study, Chromium volatilization is measured in an air-3% H2O environment at 850 °C for 336 h. Three materials coated with 600 nm Co are investigated and compared to an uncoated material. The effect of deformation is investigated on real interconnects. Microscopy observations reveal the presence of cracks in the order of several μm on the deformed pre-coated steel. However, upon exposure, the cracks can heal and form a continuous surface oxide rich in Co and Mn. As an effect of the rapid healing, no increase in Cr vaporization is measured for the pre-coated material.

  18. Investigation of metalorganic chemical vapor deposition grown CdTe/CdS solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sudharsanan, R.; Rohatgi, A. (Georgia Inst. of Tech., Atlanta (USA). School of Electrical Engineering)

    1991-03-01

    Polycrystalline CdTe films were grown on CdS/SnO{sub 2}/glass substrates by metalorganic chemical vapor deposition (MOCVD) for solar cell applications. Cells fabricated on these films showed efficiency of 9.7% which is the highest efficiency reported so far for MOCVD grown CdTe solar cells. The bias-dependent spectral response of the 9.7% efficient cell showed an external quantum efficiency greater than 0.85 at zero bias but a significant wavelength-independent reduction in spectral response at higher voltages. The interface recombination model was used to calculate the interface collection function term to quantify the open-circuit voltage (V{sub oc}) and fill factor losses in the high efficiency cell. It was found that the interface recombination reduces the V{sub oc} and fill factor by 60 mV and 0.1 respectively. It was estimated that efficiency as high as 13.5% can be achieved by improving CdTe/CdS interface quality. (orig.).

  19. Widefield microwave imaging in alkali vapor cells with sub-100 μm resolution

    Science.gov (United States)

    Horsley, Andrew; Du, Guan-Xiang; Treutlein, Philipp

    2015-11-01

    We report on widefield microwave vector field imaging with sub-100 μ {{m}} resolution using a microfabricated alkali vapor cell. The setup can additionally image dc magnetic fields, and can be configured to image microwave electric fields. Our camera-based widefield imaging system records 2D images with a 6 × 6 mm2 field of view at a rate of 10 Hz. It provides up to 50 μ {{m}} spatial resolution, and allows imaging of fields as close as 150 μ {{m}} above structures, through the use of thin external cell walls. This is crucial in allowing us to take practical advantage of the high spatial resolution, as feature sizes in near-fields are on the order of the distance from their source, and represent an order of magnitude improvement in surface-feature resolution compared to previous vapor cell experiments. We present microwave and dc magnetic field images above a selection of devices, demonstrating a microwave sensitivity of 1.4 μ {{T}} {{Hz}}-1/2 per 50× 50× 140 μ {{{m}}}3 voxel, at present limited by the speed of our camera system. Since we image 120 × 120 voxels in parallel, a single scanned sensor would require a sensitivity of at least 12 {nT} {{Hz}}-1/2 to produce images with the same sensitivity. Our technique could prove transformative in the design, characterization, and debugging of microwave devices, as there are currently no satisfactory established microwave imaging techniques. Moreover, it could find applications in medical imaging.

  20. Effect of atomic noise on optical squeezing via polarization self-rotation in a thermal vapor cell

    DEFF Research Database (Denmark)

    Hsu, M.T.L.; Hetet, G.; Peng, A.;

    2006-01-01

    show results of the characterization of PSR in isotopically enhanced rubidium-87 cells, performed in two independent laboratories. We observed that, contrary to earlier work, the presence of atomic noise in the thermal vapor overwhelms the observation of squeezing. We present a theory that contains...... atomic noise terms and show that a null result in squeezing is consistent with this theory.......The traversal of an elliptically polarized optical field through a thermal vapor cell can give rise to a rotation of its polarization axis. This process, known as polarization self-rotation (PSR), has been suggested as a mechanism for producing squeezed light at atomic transition wavelengths. We...

  1. Transcriptome sequencing reveals e-cigarette vapor and mainstream-smoke from tobacco cigarettes activate different gene expression profiles in human bronchial epithelial cells.

    Science.gov (United States)

    Shen, Yifei; Wolkowicz, Michael J; Kotova, Tatyana; Fan, Lonjiang; Timko, Michael P

    2016-01-01

    Electronic cigarettes (e-cigarettes) generate an aerosol vapor (e-vapor) thought to represent a less risky alternative to main stream smoke (MSS) of conventional tobacco cigarettes. RNA-seq analysis was used to examine the transcriptomes of differentiated human bronchial epithelial (HBE) cells exposed to air, MSS from 1R5F tobacco reference cigarettes, and e-vapor with and without added nicotine in an in vitro air-liquid interface model for cellular exposure. Our results indicate that while e-vapor does not elicit many of the cell toxicity responses observed in MSS-exposed HBE cells, e-vapor exposure is not benign, but elicits discrete transcriptomic signatures with and without added nicotine. Among the cellular pathways with the most significantly enriched gene expression following e-vapor exposure are the phospholipid and fatty acid triacylglycerol metabolism pathways. Our data suggest that alterations in cellular glycerophopholipid biosynthesis are an important consequences of e-vapor exposure. Moreover, the presence of nicotine in e-vapor elicits a cellular response distinct from e-vapor alone including alterations of cytochrome P450 function, retinoid metabolism, and nicotine catabolism. These studies establish a baseline for future analysis of e-vapor and e-vapor additives that will better inform the FDA and other governmental bodies in discussions of the risks and future regulation of these products. PMID:27041137

  2. Relaxation of atomic polarization in paraffin-coated cesium vapor cells

    CERN Document Server

    Graf, M T; Rochester, S M; Kerner, K; Wong, C; Budker, D; Alexandrov, E B; Balabas, M V

    2005-01-01

    The relaxation of atomic polarization in buffer-gas-free, paraffin-coated cesium vapor cells is studied using a variation on Franzen's technique of ``relaxation in the dark'' [Franzen, Phys. Rev. {\\bf 115}, 850 (1959)]. In the present experiment, narrow-band, circularly polarized pump light, resonant with the Cs D2 transition, orients atoms along a longitudinal magnetic field, and time-dependent optical rotation of linearly polarized probe light is measured to determine the relaxation rates of the atomic orientation of a particular hyperfine level. The change in relaxation rates during light-induced atomic desorption (LIAD) is studied. No significant change in the spin relaxation rate during LIAD is found beyond that expected from the faster rate of spin-exchange collisions due to the increase in Cs density.

  3. Characterizing passive coherent population trapping resonance in a cesium vapor cell filled with neon buffer gas

    Institute of Scientific and Technical Information of China (English)

    Liu Zhi; Wang Jie-Ying; Diao Wen-Ting; He Jun; Wang Jun-Min

    2013-01-01

    We present a pair of phase-locked lasers with a 9.2-GHz frequency difference through the injection locking of a master laser to the RF-modulation sideband of a slave diode laser.Using this laser system,a coherent population trapping (CPT)signal with a typical linewidth of ~ 182 Hz is obtained in a cesium vapor cell filled with 30 Torr (4 kPa) of neon as the buffer gas.We investigate the influence of the partial pressure of the neon buffer gas on the CPT linewidth,amplitude,and frequency shift.The results may offer some references for CPT atomic clocks and CPT atomic magnetometers.

  4. Frequency-Tunable Microwave Field Detection in an Atomic Vapor Cell

    CERN Document Server

    Horsley, Andrew

    2016-01-01

    We use an atomic vapor cell as a frequency tunable microwave field detector operating at frequencies from GHz to tens of GHz. We detect microwave magnetic fields from 2.3 GHz to 26.4 GHz, and measure the amplitude of the sigma+ component of an 18 GHz microwave field. Our proof-of-principle demonstration represents a four orders of magnitude extension of the frequency tunable range of atomic magnetometers from their previous dc to several MHz range. When integrated with a high resolution microwave imaging system, this will allow for the complete reconstruction of the vector components of a microwave magnetic field and the relative phase between them. Potential applications include near-field characterisation of microwave circuitry and devices, and medical microwave sensing and imaging.

  5. Characterization of Cs vapor cell coated with octadecyltrichlorosilane using coherent population trapping spectroscopy

    CERN Document Server

    Hafiz, Moustafa Abdel; Chutani, Ravinder; Passilly, Nicolas; Gorecki, Christophe; Guérandel, Stéphane; de Clercq, Emeric; Boudot, Rodolphe

    2015-01-01

    We report the realization and characterization using coherent population trapping (CPT) spectroscopy of an octadecyltrichlorosilane (OTS)-coated centimeter-scale Cs vapor cell. The dual-structure of the resonance lineshape, with presence of a narrow structure line at the top of a Doppler-broadened structure, is clearly observed. The linewidth of the narrow resonance is compared to the linewidth of an evacuated Cs cell and of a buffer gas Cs cell of similar size. The Cs-OTS adsorption energy is measured to be (0.42 $\\pm$ 0.03) eV, leading to a clock frequency shift rate of $2.7\\times10^{-9}/$K in fractional unit. A hyperfine population lifetime, $T_1$, and a microwave coherence lifetime, $T_2$, of 1.6 and 0.5 ms are reported, corresponding to about 37 and 12 useful bounces, respectively. Atomic-motion induced Ramsey narrowing of dark resonances is observed in Cs-OTS cells by reducing the optical beam diameter. Ramsey CPT fringes are detected using a pulsed CPT interrogation scheme. Potential applications of th...

  6. Solvent Vapor Treatment Effects on Poly(3-hexylthiophene Thin Films and its Application for Interpenetrating Heterojunction Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Masanori Ozaki

    2010-11-01

    Full Text Available The solvent vapor treatment (SVT for poly(3-hexylthiophene (PAT6 films and its application to interpenetrating heterojunction organic solar cells have been studied. It was found that SVT could improve the crystallinity and electrical characteristics of the PAT6 films. We fabricated organic solar cells with an interpenetrating structure of PAT6 and fullerenes utilizing the SVT process, and discuss the improved performance of the solar cells by taking the film crystallinity, optical properties, and morphology into consideration.

  7. 40 CFR Table 5 to Subpart IIIii of... - Required Elements of Floor-Level Mercury Vapor Measurement and Cell Room Monitoring Plans

    Science.gov (United States)

    2010-07-01

    ... Mercury Vapor Measurement and Cell Room Monitoring Plans 5 Table 5 to Subpart IIIII of Part 63 Protection... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Pt. 63, Subpt. IIIII, Table 5 Table 5 to Subpart IIIII of Part 63—Required Elements of Floor-Level Mercury Vapor...

  8. Sub-picotesla Scalar Atomic Magnetometer with a Microfabricated Vapor Cell

    Science.gov (United States)

    Zhang, Rui; Mhaskar, Rahul

    2016-05-01

    We explore the sensitivity limits of scalar atomic magnetometry with a micro-fabricated Cs vapor cell. The millimeter-scale cell is fabricated using silicon Micro-Electro-Mechanical Systems (MEMS) technology. The atomic spin procession is driven by an amplitude-modulated circularly polarized pump laser resonant with the D1 transition in Cs atoms. The precession is detected by an off-resonant linearly polarized probe laser using a balanced polarimeter setup. The probe light is spatially split into two beams to perform a gradiometer measurement. In a magnetic field of magnitude within the range of the earth magnetic field, we measure a sensitivity of less than 150 fT/ √Hz in the gradiometer mode, which shows that the magnetometer by itself can achieve sub-100 fT/ √Hz sensitivitiy. In addition to its high sensitivity, the magnetometer has a bandwidth of nearly 1 kHz due to the broad magnetic resonance inside the small cell. Our experiment suggests the feasibility of a portable, low-power and high-performance magnetometer, which can be operated in the earth's magnetic field. Such a device will greatly expand the range of applications for atomic magnetometers, such as the detection of nuclear magnetic resonance in an unshielded environment.

  9. Investigating the effects of methanol-water vapor mixture on a PBI-based high temperature PEM fuel cell

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Andreasen, Søren Juhl; Nielsen, Heidi Venstrup;

    2012-01-01

    This paper investigates the effects of methanol and water vapor on the performance of a high temperature proton exchange membrane fuel cell (HT-PEMFC). A H3PO4-doped polybenzimidazole (PBI) membrane electrode assembly (MEA), Celtec P2100 of 45 cm2 of active surface area from BASF was employed. A ...

  10. Crystal growth and evaluation of scintillation properties of Eu and alkali-metal co-doped LiSrAlF{sub 6} single crystals for thermal neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Wakahara, Shingo; Yokota, Yuui; Yamaji, Akihiro; Fujimoto, Yutaka; Sugiyama, Makoto; Kurosawa, Shunsuke [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Yanagida, Takayuki [New Industry Creation Hatchery Center (NICHe), 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Pejchal, Jan [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Institute of Physics AS CR, Cukrovarnicka 10, Prague 16253 (Czech Republic); Kawaguchi, Noriaki [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Tokuyama, Co. Ltd., Shibuya 3-chome, Shibuya-ku, Tokyo 150-8383 (Japan); Fukuda, Kentaro [Tokuyama, Co. Ltd., Shibuya 3-chome, Shibuya-ku, Tokyo 150-8383 (Japan); Yoshikawa, Akira [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe), 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

    2012-12-15

    In recent work, Na co-doping have found to improve the light output of Eu doped LiCaAlF{sub 6} (Eu:LiCAF) for thermal neutron scintillator. We grew Eu 2% and alkali metal 1% co-doped LiSAF crystals by Micro-Pulling down method to understand the effect of alkali metal co-doping on scintillation properties and mechanism compared with LiCAF. In photo- and {alpha}-ray induced radio-luminescence spectra of the all grown crystals, the emissions from d-f transition of Eu{sup 2+} were observed. Without relation to excitation source, decay times of co-doped LiSAF were longer than Eu only doped one. The light yield of Na, K and Cs co-doped LiSAF under {sup 252}Cf neutron excitation were improved. Especially, K co-doped Eu:LiSAF reached 33200 ph/n, which outperformed Eu only doped one by approximately 20% (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Simultaneous Synthesis of Dimethyl Carbonate and Poly(ethylene terephthalate) Using Alkali Metals as Catalysts%碱金属化合物催化同时合成碳酸二甲酯和聚对苯二甲酸乙二醇酯

    Institute of Scientific and Technical Information of China (English)

    张丹; 王庆印; 姚洁; 王越; 曾毅; 王公应

    2007-01-01

    Dimethyl carbonate (DMC) and poly(ethylene terephthalate) was simultaneously synthesized by the transesterification of ethylene carbonate (EC) with dimethyl terephthalate (DMT) in this paper. This reaction is an excellent green chemical process without poisonous substance. Various alkali metals were used as the catalysts. The results showed alkali metals had catalytic activity in a certain extent. The effect of reaction condition was also studied. When the reaction was carried out under the following conditions: the reaction temperature 250℃, molar ratio of EC to DMT 3: 1, reaction time 3h, and catalyst amount 0.004 (molar ratio to DMT), the yield of DMC was 68.9%.

  12. A High Temperature Calcium Vapor Cell for Spectroscopy on the 4s^2 1S0 to 4s4p 3P1 Intercombination Line

    OpenAIRE

    Erickson, Christopher J.; Neyenhuis, Brian; Durfee, Dallin S.

    2005-01-01

    We have demonstrated a high temperature vapor cell for absorption spectroscopy on the Ca intercombination line. The cell uses a dual chamber design to achieve the high temperatures necessary for an optically dense vapor while avoiding the necessity of high temperature vacuum valves and glass-to-metal seals. We have observed over 50 percent absorption in a single pass through the cell. Although pressure broadening in the cell prevented us from performing saturated-absorption spectroscopy, the ...

  13. Steep dispersion and coherent control of Faraday rotation in a potassium vapor cell

    CERN Document Server

    Lampis, Andreas; Megyeri, Balázs; Goldwin, Jon

    2015-01-01

    Electromagnetically induced transparency (EIT) was studied in a heated vapor cell of potassium without buffer gas or anti-relaxation coating. Transparency windows 60 times narrower than the natural line width and group indices exceeding 6000 were generated using a simple optical setup with a single free-running laser and an acousto-optic modulator. A longitudinal magnetic field was used to split the EIT feature into three components for either lin-perp-lin or lin-par-lin polarizations of probe and coupling beams. Measurements of polarization rotation revealed that only the lin-par-lin configuration leads to circular birefringence, an effect which we attribute to quantum interference between the multiple \\Lambda-type subsystems contributing to the signal. The Verdet constant of the EIT medium was measured to be (2.33+/-0.10)x10^5 rad/T/m, and a novel measurement of group index based on birefringence was demonstrated. For larger fields, where the individual peaks were well resolved, resonant polarization rotati...

  14. Enthalpy of Vaporization and Vapor Pressures: An Inexpensive Apparatus

    Science.gov (United States)

    Battino, Rubin; Dolson, David A.; Hall, Michael A.; Letcher, Trevor M.

    2007-01-01

    A simple and inexpensive method to determine the enthalpy of vaporization of liquids by measuring vapor pressure as a function of temperature is described. The vapor pressures measured with the stopcock cell were higher than the literature values and those measured with the sidearm rubber septum cell were both higher and lower than literature…

  15. A study of vapor CdCl{sub 2} treatment by CSS in CdS/CdTe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Rios-Flores, A.; Pena, J.L.; Castro-Pena, V.; Ares, O.; Castro-Rodriguez, R. [Applied Physics Department, CINVESTAV-IPN Merida, C.P. 97310 Merida, Yucatan (Mexico); Bosio, A. [University of Parma, Department of Physics, v.le G.P. Usberti 7/A, 43100 Parma (Italy)

    2010-06-15

    We report the effect of CdCl{sub 2} vapor treatment on the photovoltaic parameters of CdS/CdTe solar cells. Vapor treatment allows combining CdCl{sub 2} exposure time and annealing in one step. In this alternative treatment, the CdS/CdTe substrates were treated with CdCl{sub 2} vapor in a close spaced sublimation (CSS) configuration. The substrate temperature and CdCl{sub 2} powder source temperature were 400 C. The treatment was done by varying the treatment time (t) from 15 to 90 min. Such solar cells are examined by measuring their current density versus voltage (J-V) characteristics. The open-circuit voltage (V{sub oc}), short circuit current density (J{sub sc}) and fill factor (FF) of our best cell, fabricated and normalized to the area of 1 cm{sup 2}, were V{sub oc} = 663 mV, J{sub sc} = 18.5 mA/cm{sup 2} and FF = 40%, respectively, corresponding to a total area conversion efficiency of {eta} = 5%. In cells of minor area (0.1 cm{sup 2}) efficiencies of 8% have been obtained. (author)

  16. Flexible Electronics: High Pressure Chemical Vapor Deposition of Hydrogenated Amorphous Silicon Films and Solar Cells (Adv. Mater. 28/2016).

    Science.gov (United States)

    He, Rongrui; Day, Todd D; Sparks, Justin R; Sullivan, Nichole F; Badding, John V

    2016-07-01

    On page 5939, J. V. Badding and co-workers describe the unrolling of a flexible hydrogenated amorphous silicon solar cell, deposited by high-pressure chemical vapor deposition. The high-pressure deposition process is represented by the molecules of silane infiltrating the small voids between the rolled up substrate, facilitating plasma-free deposition over a very large area. The high-pressure approach is expected to also find application for 3D nanoarchitectures. PMID:27442970

  17. Ab initio study of the adsorption, diffusion, and intercalation of alkali metal atoms on the (0001) surface of the topological insulator Bi{sub 2}Se{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Ryabishchenkova, A. G., E-mail: ryaange@gmail.com; Otrokov, M. M.; Kuznetsov, V. M.; Chulkov, E. V. [Tomsk State University (Russian Federation)

    2015-09-15

    Ab initio study of the adsorption, diffusion, and intercalation of alkali metal adatoms on the (0001) step surface of the topological insulator Bi{sub 2}Se{sub 3} has been performed for the case of low coverage. The calculations of the activation energies of diffusion of adatoms on the surface and in van der Waals gaps near steps, as well as the estimate of diffusion lengths, have shown that efficient intercalation through steps is possible only for Li and Na. Data obtained for K, Rb, and Cs atoms indicate that their thermal desorption at high temperatures can occur before intercalation. The results have been discussed in the context of existing experimental data.

  18. Hot-Wire Chemical Vapor Deposition Of Polycrystalline Silicon : From Gas Molecule To Solar Cell

    Science.gov (United States)

    van Veenendaal, P. A. T. T.

    2002-10-01

    Although the effort to investigate the use of renewable energy sources, such as wind and solar energy, has increased, their contribution to the total energy consumption remains insignificant. The conversion of solar energy into electricity through solar cells is one of the most promising techniques, but the use of these cells is limited by the high cost of electricity. The major contributions to these costs are the material and manufacturing costs. Over the past decades, the development of silicon based thin film solar cells has received much attention, because the fabrication costs are low. A promising material for use in thin film solar cells is polycrystalline silicon (poly-Si:H). A relatively new technique to deposit poly-Si:H is Hot-Wire Chemical Vapor Deposition (Hot-Wire CVD), in which the reactant gases are catalytically decomposed at the surface of a hot filament, mainly tungsten and tantalum. The main advantages of Hot-Wire CVD over PE-CVD are absence of ion bombardment, high deposition rate, low equipment cost and high gas utilization. This thesis deals with the full spectrum of deposition, characterization and application of poly-Si:H thin films, i.e. from gas molecule to solar cell. Studies on the decomposition of silane on the filament showed that the process is catalytic of nature and that silane is decomposed into Si and 4H. The dominant gas phase reaction is the reaction of Si and H with silane, resulting in SiH3, Si2H6, Si3H6 and H2SiSiH2. The film growth precursors are Si, SiH3 and Si2H4. Also, XPS results on used tantalum and tungsten filaments are discussed. The position dependent measurements show larger silicon contents at the ends of the tungsten filament, as compared to the middle, due to a lower filament temperature. This effect is insignificant for a tantalum filament. Deposition time dependent measurements show an increase in silicon content of the tungsten filament with time, while the silicon content on the tantalum filament saturates

  19. The Determination of the Water Vapor Content in the Pulkovo VKM-100 Multipass Vacuum Cell Using Polymer Sensors of Humidity

    CERN Document Server

    Galkin, V D; Nikanorova, I N; Sal'nikov, I B; Leiterer, U; Alekseeva, G A; Novikov, V V; Dauß, D

    2010-01-01

    In spectral studies of water vapor under laboratory conditions (determination of molecular constants, measurement for spectral transmission functions), the amount of water vapor in the time of the measurements is one of the most essential parameters, which should be determined accurately. We discuss the application for this purpose of polymer sensors of humidity manufactured by Praktik-NC (Moscow) and used in the Pulkovo VKM-100 multipass vacuum cell. These sensors were examined in the laboratory of Lindenberg Meteorological observatory (Germany) by comparison between their readings and those of standard measuring devices for various values of relative humidity, pressure, and temperature. We also carried out measurements of relative humidity in boxes with saline solution, in which the relative humidity that corresponds to a given solution is guaranteed with the accuracy of several tenths of percent. The analysis of the results of the laboratory examination of the sensors and extended sets of measurements made...

  20. Measuring Spatial Variability of Vapor Flux to Characterize Vadose-zone VOC Sources: Flow-cell Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Mainhagu, Jon; Morrison, C.; Truex, Michael J.; Oostrom, Martinus; Brusseau, Mark

    2014-10-20

    A method termed vapor-phase tomography has recently been proposed to characterize the distribution of volatile organic contaminant mass in vadose-zone source areas, and to measure associated three-dimensional distributions of local contaminant mass discharge. The method is based on measuring the spatial variability of vapor flux, and thus inherent to its effectiveness is the premise that the magnitudes and temporal variability of vapor concentrations measured at different monitoring points within the interrogated area will be a function of the geospatial positions of the points relative to the source location. A series of flow-cell experiments was conducted to evaluate this premise. A well-defined source zone was created by injection and extraction of a non-reactive gas (SF6). Spatial and temporal concentration distributions obtained from the tests were compared to simulations produced with a mathematical model describing advective and diffusive transport. Tests were conducted to characterize both areal and vertical components of the application. Decreases in concentration over time were observed for monitoring points located on the opposite side of the source zone from the local–extraction point, whereas increases were observed for monitoring points located between the local–extraction point and the source zone. The results illustrate that comparison of temporal concentration profiles obtained at various monitoring points gives a general indication of the source location with respect to the extraction and monitoring points.

  1. Vaporization of materials in the operation of high temperature fuel cells (SOFCs); Verdampfung von Werkstoffen beim Betrieb von Hochtemperaturbrennstoffzellen (SOFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Stanislowski, M.

    2006-07-01

    One of the main problems concerning the development of state of the art planar SOFCs are the occurrence of ageing effects in long term application. To a great deal these effects are caused by the release of volatile Cr-species from metallic interconnects which leads to an inhibition of the electrochemical processes at the cathode resulting in a rapid degradation of the cell performance. A goal in further development of SOFC-systems is the reduction of the operation temperature of the cell from currently 800 C to 700 C and below. For this purpose alternative electrolyte materials with higher oxygen ion conductivities have to be developed. Doped lanthanum gallates have been identified as promising materials. However for these materials a depletion of Ga by vaporization has been observed under anodic conditions which may lead to a destruction of their electrolyte properties. The aim of this work is the study of the vaporization processes leading to the mentioned degradation effects. For this purpose an experimental setup according to the transpiration method has been developed. Concerning the vaporization of chromium the Cr release rates of the main ferritic interconnect alloys, namely Crofer 22 APU, ZMG 232, E-Brite, IT-10, IT-11, IT-14 and Ducrolloy as well as a variety of Ni- and Co-base superalloys and stainless steels with different contents of Al, Si, Ti, Mn, W, Ni and Co were measured at 800 C in air and compared to each other. The alloys that form an upper layer of Cr-Mn-spinel on top of the grown chromia scale showed a reduction of the Cr release by 61-75 % compared to pure chromia scales whereas alloys with an outer Co3O4(s) scale had a by more than 90 % reduced Cr release. For the former alloys a significant vaporization of Mn under anodic conditions could be detected. Concerning the vaporization of doped lanthanum gallates the vaporization rates of the elements Ga, Mg, Sr and La were measured as function time, temperature, gas flow rate and stoichiometry

  2. Transcriptome sequencing reveals e-cigarette vapor and mainstream-smoke from tobacco cigarettes activate different gene expression profiles in human bronchial epithelial cells

    OpenAIRE

    Yifei Shen; Michael J. Wolkowicz; Tatyana Kotova; Lonjiang Fan; Timko, Michael P.

    2016-01-01

    Electronic cigarettes (e-cigarettes) generate an aerosol vapor (e-vapor) thought to represent a less risky alternative to main stream smoke (MSS) of conventional tobacco cigarettes. RNA-seq analysis was used to examine the transcriptomes of differentiated human bronchial epithelial (HBE) cells exposed to air, MSS from 1R5F tobacco reference cigarettes, and e-vapor with and without added nicotine in an in vitro air-liquid interface model for cellular exposure. Our results indicate that while e...

  3. High-efficiency CdTe thin-film solar cells using metalorganic chemical vapor deposition techniques

    Science.gov (United States)

    Nouhi, A.; Stirn, R. J.; Meyers, P. V.; Liu, C. H.

    1989-06-01

    Energy conversion efficiency of metalorganic chemical vapor deposited CdTe as an intrinsic active layer in n-i-p solar cell structures is reported. Small-area devices with efficiencies over 9 percent have been demonstrated. I-V characteristics, photospectral response, and the results of Auger profiling of structural composition for typical devices will be presented. Also presented are preliminary results on similar photovoltaic devices having Cd(0.85)Mn(0.15)Te in place of CdTe as an i layer.

  4. High-efficiency CdTe thin-film solar cells using metalorganic chemical vapor deposition techniques

    Energy Technology Data Exchange (ETDEWEB)

    Nouhi, A.; Stirn, R.J.; Meyers, P.V.; Liu, C.H.

    1989-05-01

    Energy conversion efficiency of metalorganic chemical vapor deposited CdTe as an intrinsic active layer in n-i-p solar cell structures is reported. Small-area devices with efficiencies over 9% have been demonstrated. I--V characteristics, photospectral response, and the results of Auger profiling of structural composition for typical devices will be presented. Also presented are preliminary results on similar photovoltaic devices having Cd/sub 0.85/Mn/sub 0.15/Te in place of CdTe as an i layer.

  5. High-efficiency CdTe thin-film solar cells using metalorganic chemical vapor deposition techniques

    Science.gov (United States)

    Nouhi, A.; Stirn, R. J.; Meyers, P. V.; Liu, C. H.

    1989-01-01

    Energy conversion efficiency of metalorganic chemical vapor deposited CdTe as an intrinsic active layer in n-i-p solar cell structures is reported. Small-area devices with efficiencies over 9 percent have been demonstrated. I-V characteristics, photospectral response, and the results of Auger profiling of structural composition for typical devices will be presented. Also presented are preliminary results on similar photovoltaic devices having Cd(0.85)Mn(0.15)Te in place of CdTe as an i layer.

  6. A large sample study of spin relaxation and magnetometric sensitivity of paraffin-coated Cs vapor cells

    CERN Document Server

    Castagna, N; Di Domenico, G; Hofer, A; Knowles, P; Macchione, C; Weis, A

    2008-01-01

    We have manufactured more than 250 nominally identical paraffin-coated Cs vapor cells (30 mm diameter bulbs) for multi-channel atomic magnetometer applications. We describe our dedicated cell characterization apparatus. For each cell we have determined the intrinsic longitudinal, $\\sGamma{01}$, and transverse, $\\sGamma{02}$, relaxation rates. Our best cell shows $\\sGamma{01}/2\\pi\\approx 0.5 Hz, and $\\sGamma{02}/2\\pi\\approx 2 Hz. We find a strong correlation of both relaxation rates which we explain in terms of reservoir and spin exchange relaxation. For each cell we have determined the optimal combination of rf and laser powers which yield the highest sensitivity to magnetic field changes. Out of all produced cells, 90% are found to have magnetometric sensitivities in the range of 9 to 30 fTHz. Noise analysis shows that the magnetometers operated with such cells have a sensitivity close to the fundamental photon shot noise limit.

  7. Selective adhesion of intestinal epithelial cells on patterned films with amine functionalities formed by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Control of cell adhesion to surfaces is important to develop analytical tools in the areas of biomedical engineering. To control cell adhesiveness of the surface, we constructed a variety of plasma polymerized hexamethyldisiloxane (PPHMDSO) thin films deposited at the plasma power range of 10-100 W by plasma enhanced chemical vapor deposition (PECVD). The PPHMDSO film that was formed at 10 W was revealed to be resistant to cell adhesion. The resistance to cell adhesion is closely related to physicochemical properties of the film. Atomic force microscopic data show an increase in surface roughness from 0.52 nm to 0.74 nm with increasing plasma power. From Fourier transform infrared (FT-IR) absorption spectroscopy data, it was also determined that the methyl (-CH3) peak intensity increases with increasing plasma power, whereas the hydroxyl (-OH) peak decreases. X-ray photoelectron spectroscopy data reveal an increase in C-O bonding with increasing plasma power. These results suggest that C-O bonding and hydroxyl (-OH) and methyl (-CH3) functional groups play a critical part in cell adhesion. Furthermore, to enhance a diversity of film surface, we accumulated the patterned plasma polymerized ethylenediamine (PPEDA) thin film on the top of the PPHMDSO thin film. The PPEDA film is established to be strongly cell-adherent. This patterned two-layer film stacking method can be used to form the selectively limited cell-adhesive PPEDA spots over the adhesion-resistant surface.

  8. Selective adhesion of intestinal epithelial cells on patterned films with amine functionalities formed by plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung Seop; Choi, Changrok; Kim, Soo Heon; Choi, Kun oh [Department of Physics, Brain Korea 21 Physics Research Division and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Jeong Min [Department of Molecular Biology and Institute of Nanosensor and Biotechnology, BK21 Graduate Program for RNA Biology, Dankook University, Yongin 448-701 (Korea, Republic of); Kim, Hong Ja [Department of Internal Medicine, Dankook University College of Medicine, Cheonan 330-715 (Korea, Republic of); Yeo, Sanghak [R and D Center, ELBIO Incorporation, 426-5 Gasan-dong Geumchun-gu, Seoul (Korea, Republic of); Park, Heonyong [Department of Molecular Biology and Institute of Nanosensor and Biotechnology, BK21 Graduate Program for RNA Biology, Dankook University, Yongin 448-701 (Korea, Republic of); Jung, Donggeun, E-mail: djung@skku.ac.kr [Department of Physics, Brain Korea 21 Physics Research Division and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2010-11-01

    Control of cell adhesion to surfaces is important to develop analytical tools in the areas of biomedical engineering. To control cell adhesiveness of the surface, we constructed a variety of plasma polymerized hexamethyldisiloxane (PPHMDSO) thin films deposited at the plasma power range of 10-100 W by plasma enhanced chemical vapor deposition (PECVD). The PPHMDSO film that was formed at 10 W was revealed to be resistant to cell adhesion. The resistance to cell adhesion is closely related to physicochemical properties of the film. Atomic force microscopic data show an increase in surface roughness from 0.52 nm to 0.74 nm with increasing plasma power. From Fourier transform infrared (FT-IR) absorption spectroscopy data, it was also determined that the methyl (-CH{sub 3}) peak intensity increases with increasing plasma power, whereas the hydroxyl (-OH) peak decreases. X-ray photoelectron spectroscopy data reveal an increase in C-O bonding with increasing plasma power. These results suggest that C-O bonding and hydroxyl (-OH) and methyl (-CH{sub 3}) functional groups play a critical part in cell adhesion. Furthermore, to enhance a diversity of film surface, we accumulated the patterned plasma polymerized ethylenediamine (PPEDA) thin film on the top of the PPHMDSO thin film. The PPEDA film is established to be strongly cell-adherent. This patterned two-layer film stacking method can be used to form the selectively limited cell-adhesive PPEDA spots over the adhesion-resistant surface.

  9. Comparison of gold nanoparticle mediated photoporation: vapor nanobubbles outperform direct heating for delivering macromolecules in live cells.

    Science.gov (United States)

    Xiong, Ranhua; Raemdonck, Koen; Peynshaert, Karen; Lentacker, Ine; De Cock, Ine; Demeester, Jo; De Smedt, Stefaan C; Skirtach, Andre G; Braeckmans, Kevin

    2014-06-24

    There is a great interest in delivering macromolecular agents into living cells for therapeutic purposes, such as siRNA for gene silencing. Although substantial effort has gone into designing nonviral nanocarriers for delivering macromolecules into cells, translocation of the therapeutic molecules from the endosomes after endocytosis into the cytoplasm remains a major bottleneck. Laser-induced photoporation, especially in combination with gold nanoparticles, is an alternative physical method that is receiving increasing attention for delivering macromolecules in cells. By allowing gold nanoparticles to bind to the cell membrane, nanosized membrane pores can be created upon pulsed laser illumination. Depending on the laser energy, pores are created through either direct heating of the AuNPs or by vapor nanobubbles (VNBs) that can emerge around the AuNPs. Macromolecules in the surrounding cell medium can then diffuse through the pores directly into the cytoplasm. Here we present a systematic evaluation of both photoporation mechanisms in terms of cytotoxicity, cell loading, and siRNA transfection efficiency. We find that the delivery of macromolecules under conditions of VNBs is much more efficient than direct photothermal disturbance of the plasma membrane without any noticeable cytotoxic effect. Interestingly, by tuning the laser energy, the pore size could be changed, allowing control of the amount and size of molecules that are delivered in the cytoplasm. As only a single nanosecond laser pulse is required, we conclude that VNBs are an interesting photoporation mechanism that may prove very useful for efficient high-throughput macromolecular delivery in live cells.

  10. Competitive binding exchange between alkali metal ions (K+, Rb+, and Cs+) and Na+ ions bound to the dimeric quadruplex [d(G4T4G4)]2: a 23Na and 1H NMR study.

    Science.gov (United States)

    Cesare Marincola, Flaminia; Virno, Ada; Randazzo, Antonio; Mocci, Francesca; Saba, Giuseppe; Lai, Adolfo

    2009-12-01

    A comparative study of the competitive cation exchange between the alkali metal ions K+, Rb+, and Cs+ and the Na+ ions bound to the dimeric quadruplex [d(G4T4G4)]2 was performed in aqueous solution by a combined use of the 23Na and 1H NMR spectroscopy. The titration data confirm the different binding affinities of these ions for the G-quadruplex and, in particular, major differences in the behavior of Cs+ as compared to the other ions were found. Accordingly, Cs+ competes with Na+ only for the binding sites at the quadruplex surface (primarily phosphate groups), while K+ and Rb+ are also able to replace sodium ions located inside the quadruplex. Furthermore, the 1H NMR results relative to the CsCl titration evidence a close approach of Cs+ ions to the phosphate groups in the narrow groove of [d(G4T4G4)]2. Based on a three-site exchange model, the 23Na NMR relaxation data lead to an estimate of the relative binding affinity of Cs+ versus Na+ for the quadruplex surface of 0.5 at 298 K. Comparing this value to those reported in the literature for the surface of the G-quadruplex formed by 5'-guanosinemonophosphate and for the surface of double-helical DNA suggests that topology factors may have an important influence on the cation affinity for the phosphate groups on DNA.

  11. New Alkali-Metal- and 2-Phenethylamine-Intercalated Superconductors Ax(C8H11N)yFe1-zSe (A = Li, Na) with the Largest Interlayer Spacings and Tc ˜ 40 K

    Science.gov (United States)

    Hatakeda, Takehiro; Noji, Takashi; Sato, Kazuki; Kawamata, Takayuki; Kato, Masatsune; Koike, Yoji

    2016-10-01

    New FeSe-based intercalation superconductors, Ax(C8H11N)yFe1-zSe (A = Li, Na), with Tc = 39-44 K have been successfully synthesized via the intercalation of alkali metals and 2-phenethylamine into FeSe. The interlayer spacings, namely, the distances between neighboring Fe layers, d, of Ax(C8H11N)yFe1-zSe (A = Li, Na) are 19.04(6) and 18.0(1) Å, respectively. These d values are the largest among those of the FeSe-based intercalation compounds and are understood to be due to the intercalation of two molecules of 2-phenethylamine in series perpendicular to the FeSe layers. It appears that the relationship between Tc and d in the FeSe-based intercalation superconductors is not domic but Tc is saturated at ˜45 K, which is comparable to the Tc values of single-layer FeSe films, for d ≥ 9 Å.

  12. Collapse and revival of a Dicke-type coherent narrowing in potassium vapor confined in a nanometric thin cell

    Science.gov (United States)

    Sargsyan, Armen; Pashayan-Leroy, Yevgenya; Leroy, Claude; Sarkisyan, David

    2016-04-01

    A nanometer-thin cell (in the direction of laser beam propagation) has been elaborated with the thickness of the atomic vapor column varying smoothly in the range of L=50-1500 {nm}. The cell allows one to study the behavior of the resonance absorption over the D 1 line of potassium atoms by varying the laser intensity and the cell thickness (from L=λ /2 to L=2λ with the step λ /2 where λ =770 {nm} is the resonant wavelength of the laser). It is shown that despite the huge Doppler broadening (\\gt 0.9 {GHz} at the cell temperature 170{}\\circ {{C}}), at low laser intensities a narrowing of the resonance absorption spectrum is observed for L=λ /2 (∼ 120 {MHz} at FWHM) and L=3/2λ , whereas for L=λ and L=2λ the spectrum broadens. At moderate laser intensities narrowband velocity selective optical pumping (VSOP) resonances appear at L=λ and L=2λ with the linewidth close to the natural one. A comparison with saturated absorption spectra obtained in a 1.4 cm-sized K cell is presented. The developed theoretical model well describes the experiment.

  13. Resolving the nanostructure of plasma-enhanced chemical vapor deposited nanocrystalline SiOx layers for application in solar cells

    Science.gov (United States)

    Klingsporn, M.; Kirner, S.; Villringer, C.; Abou-Ras, D.; Costina, I.; Lehmann, M.; Stannowski, B.

    2016-06-01

    Nanocrystalline silicon suboxides (nc-SiOx) have attracted attention during the past years for the use in thin-film silicon solar cells. We investigated the relationships between the nanostructure as well as the chemical, electrical, and optical properties of phosphorous, doped, nc-SiO0.8:H fabricated by plasma-enhanced chemical vapor deposition. The nanostructure was varied through the sample series by changing the deposition pressure from 533 to 1067 Pa. The samples were then characterized by X-ray photoelectron spectroscopy, spectroscopic ellipsometry, Raman spectroscopy, aberration-corrected high-resolution transmission electron microscopy, selected-area electron diffraction, and a specialized plasmon imaging method. We found that the material changed with increasing pressure from predominantly amorphous silicon monoxide to silicon dioxide containing nanocrystalline silicon. The nanostructure changed from amorphous silicon filaments to nanocrystalline silicon filaments, which were found to cause anisotropic electron transport.

  14. ZnO/Cu(InGa)Se.sub.2 solar cells prepared by vapor phase Zn doping

    Science.gov (United States)

    Ramanathan, Kannan; Hasoon, Falah S.; Asher, Sarah E.; Dolan, James; Keane, James C.

    2007-02-20

    A process for making a thin film ZnO/Cu(InGa)Se.sub.2 solar cell without depositing a buffer layer and by Zn doping from a vapor phase, comprising: depositing Cu(InGa)Se.sub.2 layer on a metal back contact deposited on a glass substrate; heating the Cu(InGa)Se.sub.2 layer on the metal back contact on the glass substrate to a temperature range between about 100.degree. C. to about 250.degree. C.; subjecting the heated layer of Cu(InGa)Se.sub.2 to an evaporant species from a Zn compound; and sputter depositing ZnO on the Zn compound evaporant species treated layer of Cu(InGa)Se.sub.2.

  15. Collapse and revival of a Dicke-type coherent narrowing in potassium vapor confined in a nanometric-thin cell

    CERN Document Server

    Sargsyan, A; Leroy, C; Sarkisyan, D

    2015-01-01

    A nanometer-thin-cell (in the direction of laser beam propagation) has been elaborated with the thickness of the atomic vapor column varying smoothly in the range of $L = \\unit[50-1500]{nm}$. The cell allows one to study the behavior of the resonance absorption over the $D_1$ line of potassium atoms by varying the laser intensity and the cell thickness from $L = \\lambda / 2$ to $L = 2 \\lambda$ with the step $\\lambda/2$ ($\\lambda =\\unit[770]{nm}$ is the resonant wavelength of the laser). It is shown that despite the huge Doppler broadening ($>\\unit[0.9]{GHz}$ at the cell temperature $\\unit[170]{^{\\circ}C}$), at low laser intensities a narrowing of the resonance absorption spectrum is observed for $L = \\lambda/2$ ($\\sim \\unit[120]{ MHz}$ at FWHM) and $L = 3/2 \\lambda$, whereas for $L = \\lambda$ and $L =2\\lambda$ the spectrum broadens. At moderate laser intensities narrowband velocity selective optical pumping (VSOP) resonances appear at $L = \\lambda$ and $L=2\\lambda $ with the linewidth close to the natural one...

  16. Low-Temperature Process for Atomic Layer Chemical Vapor Deposition of an Al2O3 Passivation Layer for Organic Photovoltaic Cells.

    Science.gov (United States)

    Kim, Hoonbae; Lee, Jihye; Sohn, Sunyoung; Jung, Donggeun

    2016-05-01

    Flexible organic photovoltaic (OPV) cells have drawn extensive attention due to their light weight, cost efficiency, portability, and so on. However, OPV cells degrade quickly due to organic damage by water vapor or oxygen penetration when the devices are driven in the atmosphere without a passivation layer. In order to prevent damage due to water vapor or oxygen permeation into the devices, passivation layers have been introduced through methods such as sputtering, plasma enhanced chemical vapor deposition, and atomic layer chemical vapor deposition (ALCVD). In this work, the structural and chemical properties of Al2O3 films, deposited via ALCVD at relatively low temperatures of 109 degrees C, 200 degrees C, and 300 degrees C, are analyzed. In our experiment, trimethylaluminum (TMA) and H2O were used as precursors for Al2O3 film deposition via ALCVD. All of the Al2O3 films showed very smooth, featureless surfaces without notable defects. However, we found that the plastic flexible substrate of an OPV device passivated with 300 degrees C deposition temperature was partially bended and melted, indicating that passivation layers for OPV cells on plastic flexible substrates need to be formed at temperatures lower than 300 degrees C. The OPV cells on plastic flexible substrates were passivated by the Al2O3 film deposited at the temperature of 109 degrees C. Thereafter, the photovoltaic properties of passivated OPV cells were investigated as a function of exposure time under the atmosphere.

  17. Low-Temperature Process for Atomic Layer Chemical Vapor Deposition of an Al2O3 Passivation Layer for Organic Photovoltaic Cells.

    Science.gov (United States)

    Kim, Hoonbae; Lee, Jihye; Sohn, Sunyoung; Jung, Donggeun

    2016-05-01

    Flexible organic photovoltaic (OPV) cells have drawn extensive attention due to their light weight, cost efficiency, portability, and so on. However, OPV cells degrade quickly due to organic damage by water vapor or oxygen penetration when the devices are driven in the atmosphere without a passivation layer. In order to prevent damage due to water vapor or oxygen permeation into the devices, passivation layers have been introduced through methods such as sputtering, plasma enhanced chemical vapor deposition, and atomic layer chemical vapor deposition (ALCVD). In this work, the structural and chemical properties of Al2O3 films, deposited via ALCVD at relatively low temperatures of 109 degrees C, 200 degrees C, and 300 degrees C, are analyzed. In our experiment, trimethylaluminum (TMA) and H2O were used as precursors for Al2O3 film deposition via ALCVD. All of the Al2O3 films showed very smooth, featureless surfaces without notable defects. However, we found that the plastic flexible substrate of an OPV device passivated with 300 degrees C deposition temperature was partially bended and melted, indicating that passivation layers for OPV cells on plastic flexible substrates need to be formed at temperatures lower than 300 degrees C. The OPV cells on plastic flexible substrates were passivated by the Al2O3 film deposited at the temperature of 109 degrees C. Thereafter, the photovoltaic properties of passivated OPV cells were investigated as a function of exposure time under the atmosphere. PMID:27483916

  18. Gas cell based on optical contacting for fundamental spectroscopy studies with initial reference absorption spectrum of H2O vapor at 1723 K and 0.0235 bar

    Science.gov (United States)

    Melin, Scott T.; Sanders, Scott T.

    2016-09-01

    A gas cell, using optically contacted sapphire windows to form a hot vapor seal, has been created for high temperature fundamental spectroscopy studies. It is designed to operate at temperatures from 280-2273 K and pressures from vacuum to 1.3 bar. Using the cell in conjunction with an external cavity diode laser spectrometer, a reference H2O vapor absorption spectrum at P=0.0235±0.0036 bar and T=1723±6 K was measured with 0.0001 cm-1 resolution over the 7326-7598 cm-1 range. Comparison of the measured spectrum to simulations reveals errors in both the HITEMP and BT2 databases. This work establishes heated static cell capabilities at temperatures well above the typical limit of approximately 1300 K set by quartz material properties. This paper addresses the design of the cell as well as the cell's limitations.

  19. The first pseudo-ternary thiocyanate containing two alkali metals. Synthesis and single-crystal structure of LiK{sub 2}[SCN]{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Reckeweg, Olaf; DiSalvo, Francis J. [Cornell Univ., Ithaca, NY (United States). Baker Lab.

    2016-04-01

    A procedure was empirically developed to prepare the compound LiK{sub 2}[SCN]{sub 3}, which forms colorless, transparent, very fragile, and extremely hygroscopic thin rectangular plates. Its unique crystal structure was determined by single-crystal X-ray diffraction. LiK{sub 2}[SCN]{sub 3} adopts the orthorhombic space group Pna2{sub 1} (no. 33, Z = 4) with the cell parameters a = 1209.32(9), b = 950.85(9), and c = 849.95(6) pm.

  20. Vector light shift averaging in paraffin-coated alkali vapor cells

    Science.gov (United States)

    Zhivun, Elena; Wickenbrock, Arne; Sudyka, Julia; Patton, Brian; Pustelny, Szymon; Budker, Dmitry

    2016-07-01

    Light shifts are an important source of noise and systematics in optically pumped magnetometers. We demonstrate that the long spin coherence time in paraffin-coated cells leads to spatial averaging of the light shifts over the entire cell volume. This renders the averaged light shift independent, under certain approximations, of the light-intensity distribution within the sensor cell. These results and the underlying mechanism can be extended to other spatially varying phenomena in anti-relaxation-coated cells with long coherence times.

  1. Vector light shift averaging in paraffin-coated alkali vapor cells

    Science.gov (United States)

    Zhivun, Elena; Wickenbrock, Arne; Sudyka, Julia; Patton, Brian; Pustelny, Szymon; Budker, Dmitry

    2016-05-01

    Light shifts are an important source of noise and systematics in optically pumped magnetometers. We demonstrate that the long spin coherence time in paraffin-coated cells leads to spatial averaging of the light shifts over the entire cell volume. This renders the averaged light shift independent, under certain approximations, of the light-intensity distribution within the sensor cell. These results and the underlying mechanism can be extended to other spatially varying phenomena in anti-relaxation-coated cells with long coherence times.

  2. GaAs Solar Cells Grown by Hydride Vapor-Phase Epitaxy and the Development of GaInP Cladding Layers

    Energy Technology Data Exchange (ETDEWEB)

    Simon, John; Schulte, Kevin L.; Young, David L.; Haegel, Nancy M.; Ptak, Aaron J.

    2016-01-01

    The high cost of high-efficiency III-V photovoltaic devices currently limits them to niche markets. Hydride vapor-phase epitaxy (HVPE) growth of III-V materials recently reemerged as a low-cost, high-throughput alternative to conventional metal- organic vapor-phase epitaxy (MOVPE) growth of high-efficiency solar cells. Previously, we demonstrated unpassivated HVPEgrown GaAs p-n junctions with good quantum efficiency and high open-circuit voltage (Voc). In this work, we demonstrate the growth of GaInPby HVPE for use as a high-quality surface passivation layer to GaAs solar cells. Solar cells grown with GaInP window layers show significantly improved quantum efficiency compared with unpassivated cells, increasing the short-circuit current (JSC) of these low-cost devices. These results show the potential of low-cost HVPE for the growth of high-quality III-V devices.

  3. A High Temperature Calcium Vapor Cell for Spectroscopy on the 4s^2 1S0 to 4s4p 3P1 Intercombination Line

    CERN Document Server

    Erickson, C J; Durfee, D S; Erickson, Christopher J.; Neyenhuis, Brian; Durfee, Dallin S.

    2005-01-01

    We have demonstrated a high temperature vapor cell for absorption spectroscopy on the Ca intercombination line. The cell uses a dual chamber design to achieve the high temperatures necessary for an optically dense vapor while avoiding the necessity of high temperature vacuum valves and glass-to-metal seals. We have observed over 50 percent absorption in a single pass through the cell. Although pressure broadening in the cell prevented us from performing saturated-absorption spectroscopy, the broadening resulted in higher signal-to-noise ratios by allowing us to probe the atoms with intensities much greater than the 0.2 uW/cm^2 saturation intensity of the unbroadened transition.

  4. CdTe-based solar cells prepared by physical vapor deposition and close-spaced sublimation methods

    International Nuclear Information System (INIS)

    Full text : In the photovoltaic material family, cadmium telluride is regarded as one of the most promising material for fabrication of high efficiency polycrystalline CdTe/CdS thin film solar cells because of its near-optimum band gap of about 1.46 eV and high optical absorption coefficient in visible range. The maximum efficiency of about 16.5 percent of the laboratory samples of polycrystalline CdTe based thin film solar cells was achieved by using nanostructured CdS:O window layer and the modified device structure. In spite of the large lattice mismatch between cubic CdTe and hexagonal CdS (nearly 9.7 percent) the CdTe/CdS solar cells are characterized by essentially high efficiencies caused by interdiffusion at the junction interface removing the lattice mismatch. To identify the structural mechanisms leading to the solar cell efficiency increase we have studied the effect of CdCl2 treatment on the output parameters of CdS/CdTe-based solar cells and crystal structure of the base layers deposited on glass substrates by different ways. In the first way both of CdS and CdTe layers were deposited by physical vapor deposition (PVD) method meanwhile in the second way the chemical bath deposition (CBD) and close-spaced sublimation (CSS) methods were used for CdS and CdTe films deposition, respectively. For the PVD structures. The average grain size of the film increases from 1 μm to 4 μm due to the lattice strain caused by macrodeformations and stacking faults. The maximum efficiency (ηA=10.3 percent) of solar cells on the basis of cadmium telluride layers deposited by PVD method corresponds to 0,35 μm CdRl2 thickness at CdCl2 treatment. CBD/CSS samples were exposed to CdCl2 vapor at 400 degrees Celsium for 5-7 min in vacuum chamber in the presence of 100 torr oxygen and 400 torr helium. As-grown CdTe films were characterized by clearly faceted surface morphology and an average grain size of about 3-4 μm. Unlike the thermally evaporated CdTe films, no

  5. Growth of Cu2ZnSnSe4 Film under Controllable Se Vapor Composition and Impact of Low Cu Content on Solar Cell Efficiency.

    Science.gov (United States)

    Li, Jianjun; Wang, Hongxia; Wu, Li; Chen, Cheng; Zhou, Zhiqiang; Liu, Fangfang; Sun, Yun; Han, Junbo; Zhang, Yi

    2016-04-27

    It is a challenge to fabricate high quality Cu2ZnSnSe4 (CZTSe) film with low Cu content (Cu/(Zn + Sn) CZTSe films under different Se vapor composition are investigated by DC-sputtering and a postselenization approach. The composition of Se vapor has important influence on the compactability of the films and the diffusion of elements in the CZTSe films. By adjusting the composition of Se vapor during the selenization process, an optimized two step selenization process is proposed and highly crystallized CZTSe film with low Cu content (Cu/(Zn + Sn) = 0.75) is obtained. Further study of the effect of Cu content on the morphology and photovoltaic performance of the corresponding CZTSe solar cells has shown that the roughness of the CZTSe absorber film increases when Cu content decreases. As a consequence, the reflection loss of CZTSe solar cells reduces dramatically and the short circuit current density of the cells improve from 34.7 mA/cm(2) for Cu/(Zn + Sn) = 0.88 to 38.5 mA/cm(2) for Cu/(Zn + Sn) = 0.75. In addition, the CZTSe solar cells with low Cu content show longer minority carrier lifetime and higher open circuit voltage than the high Cu content devices. A champion performance CZTSe solar cell with 10.4% efficiency is fabricated with Cu/(Zn + Sn) = 0.75 in the CZTSe film without antireflection coating. PMID:27058738

  6. Transport properties of alkali metal doped fullerides

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Daluram, E-mail: daluramyadav@gmail.com; Yadav, Nishchhal, E-mail: somyadav@gmail.com [School of studies in Physics, Vikram University, Ujjain (M.P) India (India)

    2015-07-31

    We have studied the intercage interactions between the adjacent C{sub 60} cages and expansion of lattice due to the intercalation of alkali atoms based on the spring model to estimate phonon frequencies from the dynamical matrix for the intermolecular alkali-C{sub 60} phonons. We considered a two-peak model for the phonon density of states to investigate the nature of electron pairing mechanism for superconducting state in fullerides. Coulomb repulsive parameter and the electron phonon coupling strength are obtained within the random phase approximation. Transition temperature, T{sub c}, is obtained in a situation when the free electrons in lowest molecular orbital are coupled with alkali-C{sub 60} phonons as 5 K, which is much lower as compared to reported T{sub c} (20 K). The superconducting pairing is mainly driven by the high frequency intramolecular phonons and their effects enhance it to 22 K. The importance of the present study, the pressure effect and normal state transport properties are calculated within the same model leading superconductivity.

  7. An equation of state for alkali metals

    Science.gov (United States)

    Arafin, Sayyadul; Singh, Ram N.

    2016-04-01

    Semi-empirical equations of state based on Lindemann's law have been developed to determine the pressure (P) dependence of the melting temperature (Tm) of Li, K, Rb and Cs. The basic inputs are Grüneisen parameter and the bulk modulus. Tm-P variations exhibit maximum melting temperature with concave downwards. The maximum in Tm for Cs is found to occur at pressure of 2.2 GPa whereas for Li, K and Rb it falls in the range of 7-9.5 GPa. The predicted values of Tm as a function of pressure, based on the present empirical relation, fit quite well with the available experimental data. The empirical relation can also be used to extrapolate Tm at higher pressure from the values available at lower pressures.

  8. Alkali-metal ion coordination in uranyl(VI) poly-peroxide complexes in solution. Part 1: the Li⁺, Na⁺ and K⁺--peroxide-hydroxide systems.

    Science.gov (United States)

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

    2015-01-28

    The alkali metal ions Li(+), Na(+) and K(+) have a profound influence on the stoichiometry of the complexes formed in uranyl(VI)-peroxide-hydroxide systems, presumably as a result of a templating effect, resulting in the formation of two complexes, M[(UO2)(O2)(OH)]2(-) where the uranyl units are linked by one peroxide bridge, μ-η(2)-η(2), with the second peroxide coordinated "end-on", η(2), to one of the uranyl groups, and M[(UO2)(O2)(OH)]4(3-), with a four-membered ring of uranyl ions linked by μ-η(2)-η(2) peroxide bridges. The stoichiometry and equilibrium constants for the reactions: M(+) + 2UO2(2+) + 2HO2(-) + 2H2O → M[(UO2)(O2)(OH)]2(-) + 4H(+) (1) and M(+) + 4UO2(2+) + 4HO2(-) + 4H2O → M[(UO2)(O2)(OH)]4(3-) + 8H(+) (2) have been measured at 25 °C in 0.10 M (tetramethyl ammonium/M(+))NO3 ionic media using reaction calorimetry. Both reactions are strongly enthalpy driven with large negative entropies of reaction; the observation that ΔH(2) ≈ 2ΔH(1) suggests that the enthalpy of reaction is approximately the same when peroxide is added in bridging and "end-on" positions. The thermodynamic driving force in the reactions is the formation of strong peroxide bridges and the role of M(+) cations is to provide a pathway with a low activation barrier between the reactants and in this way "guide" them to form peroxide bridged complexes; they play a similar role as in the synthesis of crown-ethers. Quantum chemical (QC) methods were used to determine the structure of the complexes, and to demonstrate how the size of the M(+)-ions affects their coordination geometry. There are several isomers of Na[(UO2)(O2)(OH)]2(-) and QC energy calculations show that the ones with a peroxide bridge are substantially more stable than the ones with hydroxide bridges. There are isomers with different coordination sites for Na(+) and the one with coordination to the peroxide bridge and two uranyl oxygen atoms is the most stable one.

  9. Development of Detection Method for Chlorates of Alkali Metals in Cosmetics%化妆品中碱金属氯酸盐的检测方法研究

    Institute of Scientific and Technical Information of China (English)

    杨轶眉; 李勤; 薛峰

    2014-01-01

    A thin layer chromatography(TCL)&potentiometric titration method was developed for the determination of chlo-rates of alkali metals in cosmetics. Chlorates were separated from other halates by thin layer chromatography and identified by the oxidation of iodide to form iodine. After identification,chlorate was reduced by zinc powder under acid conditions. The formed chloride was measured by potentiometric titration using a silver nitrate solution. The results showed that the recovery of the method was in the range of 81.4% to 105.2% under the concentration of 0.03% to 3.41% while being counted as chlorate ions(with relative standard deviation of not more than 10% ). Additionally,the detection and quantification limits were found to be 0.03% and 0.10% respectively.%建立了薄层色谱法和电位滴定法联用测定化妆品中碱金属氯酸盐含量的方法。用薄层色谱将氯酸盐从其他卤酸盐中分离,与碘化物形成碘来鉴别碱金属的氯酸盐。通过鉴别试验后,在酸性条件下氯酸盐被锌粉还原,所形成的氯化物用硝酸银溶液进行电位滴定。试验结果表明:在0.03%~3.41%(以氯酸根离子计)的质量分数范围内,加标回收率为81.4%~105.2%,相对标准偏差(RSD)≤10%;定性检出限为0.03%(质量分数),定量检出限为0.10%(质量分数)。

  10. Spatial transport of atomic coherence in electromagnetically induced absorption with a paraffin-coated Rb vapor cell.

    Science.gov (United States)

    Lee, Yoon-Seok; Moon, Han Seb

    2014-06-30

    We report the spatial transport of spontaneously transferred atomic coherence (STAC) in electromagnetically induced absorption (EIA), which resulted from moving atoms with the STAC of the 5S(1/2) (F = 2)-5P(3/2) (F' = 3) transition of (87)Rb in a paraffin-coated vapor cell. In our experiment, two channels were spatially separate; the writing channel (WC) generated STAC in the EIA configuration, and the reading channel (RC) retrieved the optical field from the spatially transported STAC. Transported between the spatially separated positions, the fast light pulse of EIA in the WC and the delayed light pulse in the RC were observed. When the laser direction of the RC was counter-propagated in the direction of the WC, we observed direction reversal of the transported light pulse in the EIA medium. Furthermore, the delay time, the magnitude, and the width of the spatially transported light pulse were investigated with respect to the distance between the two channels.

  11. A low phase noise microwave frequency synthesis for a high-performance cesium vapor cell atomic clock

    Energy Technology Data Exchange (ETDEWEB)

    François, B.; Boudot, R. [FEMTO-ST, CNRS, Université de Franche-Comté, 26 chemin de l' Epitaphe, 25030 Besançon (France); Calosso, C. E. [INRIM, Strada delle Cacce 91, 10135 Torino (Italy); Danet, J. M. [LNE-SYRTE, Observatoire de Paris, CNRS-UPMC, 61 avenue de l' Observatoire, 75014 Paris (France)

    2014-09-15

    We report the development, absolute phase noise, and residual phase noise characterization of a 9.192 GHz microwave frequency synthesis chain devoted to be used as a local oscillator in a high-performance cesium vapor cell atomic clock based on coherent population trapping (CPT). It is based on frequency multiplication of an ultra-low phase noise 100 MHz oven-controlled quartz crystal oscillator using a nonlinear transmission line-based chain. Absolute phase noise performances of the 9.192 GHz output signal are measured to be −42, −100, −117 dB rad{sup 2}/Hz and −129 dB rad{sup 2}/Hz at 1 Hz, 100 Hz, 1 kHz, and 10 kHz offset frequencies, respectively. Compared to current results obtained in a state-of-the-art CPT-based frequency standard developed at LNE-SYRTE, this represents an improvement of 8 dB and 10 dB at f = 166 Hz and f = 10 kHz, respectively. With such performances, the expected Dick effect contribution to the atomic clock short term frequency stability is reported at a level of 6.2 × 10{sup −14} at 1 s integration time, that is a factor 3 higher than the atomic clock shot noise limit. Main limitations are pointed out.

  12. Vapor and healing treatment for CH3NH3PbI3-xClx films toward large-area perovskite solar cells

    Science.gov (United States)

    Gouda, Laxman; Gottesman, Ronen; Tirosh, Shay; Haltzi, Eynav; Hu, Jiangang; Ginsburg, Adam; Keller, David A.; Bouhadana, Yaniv; Zaban, Arie

    2016-03-01

    Hybrid methyl-ammonium lead trihalide perovskites are promising low-cost materials for use in solar cells and other optoelectronic applications. With a certified photovoltaic conversion efficiency record of 20.1%, scale-up for commercial purposes is already underway. However, preparation of large-area perovskite films remains a challenge, and films of perovskites on large electrodes suffer from non-uniform performance. Thus, production and characterization of the lateral uniformity of large-area films is a crucial step towards scale-up of devices. In this paper, we present a reproducible method for improving the lateral uniformity and performance of large-area perovskite solar cells (32 cm2). The method is based on methyl-ammonium iodide (MAI) vapor treatment as a new step in the sequential deposition of perovskite films. Following the MAI vapor treatment, we used high throughput techniques to map the photovoltaic performance throughout the large-area device. The lateral uniformity and performance of all photovoltaic parameters (Voc, Jsc, Fill Factor, Photo-conversion efficiency) increased, with an overall improved photo-conversion efficiency of ~100% following a vapor treatment at 140 °C. Based on XRD and photoluminescence measurements, We propose that the MAI treatment promotes a ``healing effect'' to the perovskite film which increases the lateral uniformity across the large-area solar cell. Thus, the straightforward MAI vapor treatment is highly beneficial for large scale commercialization of perovskite solar cells, regardless of the specific deposition method.Hybrid methyl-ammonium lead trihalide perovskites are promising low-cost materials for use in solar cells and other optoelectronic applications. With a certified photovoltaic conversion efficiency record of 20.1%, scale-up for commercial purposes is already underway. However, preparation of large-area perovskite films remains a challenge, and films of perovskites on large electrodes suffer from non

  13. Physical vapor deposition of CdTe thin films at low temperature for solar cell applications

    International Nuclear Information System (INIS)

    Cadmium telluride is successfully utilized as an absorber material for thin film solar cells. Industrial production makes use of high substrate temperatures for the deposition of CdTe absorber layers. However, in order to exploit flexible substrates and to simplify the manufacturing process, lower deposition temperatures are beneficial. Based on the phase diagram of CdTe, predictions on the stoichiometry of CdTe thin films grown at low substrate temperatures are made in this work. These predictions were verified experimentally using additional sources of Cd and Te during the deposition of the CdTe thin films at different substrate temperatures. The deposited layers were analyzed with energy-dispersive X-ray spectroscopy. In case of CdTe layers which were deposited at substrate temperatures lower than 200 C without usage of additional sources we found a non-stoichiometric growth of the CdTe layers. The application of the additional sources leads to a stoichiometric growth for substrate temperatures down to 100 C which is a significant reduction of the substrate temperature during deposition.

  14. ``HYTEC''—A thermally regenerative fuel cell

    Science.gov (United States)

    Roy, Prodyot; Salamah, Samir A.; Maldonado, Jerry; Narkiewicz, Regina S.

    1993-01-01

    HYTEC (Hydrogen Thermo-Electrochemical Converter) is a thermally regenerative fuel cell for direct conversion of heat into electricity. The principles of basic cell operation involve ionic transport of hydrogen through a hydride-ion (H-) conducting, molten electrolyte, and reaction with alkali metals, oxygen, or air. In order to operate HYTEC in a thermally regenerative mode, pure Li and Na, or a mixture of Li/Na alloy, is used for reaction with hydrogen, to form metal hydride which is subsequently decomposed to metal and hydrogen at higher temperatures. The reactants are then separated and redirected to the electrochemical cell. In the cell the molten, H--conducting electrolyte is immobilized between two thin hydrogen-permeable, solid, metallic electrodes which also act as current collectors. The H2 gas first diffuses through the cathode electrode and forms a hydride ion (H+e→H-) at the cathode-electrolyte interface. The H- ion subsequently migrated through the electrolyte under a chemical potential gradient created by the presence of the alkali metal in the anode chamber. The H- ion releases the electron to form hydrogen atoms (H-→H+e) at the anode-electrolyte interface. The hydrogen atom diffuses through the anode electrode and reacts with the alkali metal to form metal hydride. The electron released passes through the load circuit to complete the cycle. In the regeneration scheme, the fuel cell is operated at temperature T1. The metal hydride formed at the anode is pumped to the decomposition chamber through a recuperator. The metal hydride is decomposed at a higher temperature, T2, by an external heat source. The H2 gas is separated from the alkali metal by a H2-permeable, solid, metallic membrane and fed into the anode chamber of the cell. The hydrogen-depleted alkali metal is directed to the cathode chamber of the cell, via the recuperator, to complete the cycle. To date, electrochemical feasibility of the concept has been experimentally demonstrated. A

  15. Evidence for [18-Crown-6 Na]2[S2O4] in methanol and dissociation to Na2S2O4 and 18-Crown-6 in the solid state; accounting for the scarcity of simple oxy dianion salts of alkali metal crown ethers in the solid state.

    Science.gov (United States)

    Bruna, Pablo J; Greer, Scott; Passmore, Jack; Rautiainen, J Mikko

    2011-02-21

    [18-Crown-6 Na](2)S(2)O(4) complex was prepared in methanol solution but dissociates into 18-Crown-6 ((s)) and Na(2)S(2)O(4 (s)) on removal of the solvent. Evidence for complexation in methanol is supported by a quantitative mass analysis and the dissociation in the solid state by vibrational spectroscopy and powder X-ray diffraction. These observations are accounted for by investigating the energetics of complexation in solution and dissociation in the solid state using calculated density functional theory (DFT) gas phase binding enthalpies and free energies combined with conductor-like screening model (COSMO) solvation energies and lattice enthalpy and free energy terms derived from volume based thermodynamics (VBT). Our calculations show that complexation of alkali metal dianion salts to crown ethers are much less favorable than that of the corresponding monoanion salts in the solid state and that the formation of alkali metal crown complexes of stable simple oxy-dianion (e.g., CO(3)(2-), SO(4)(2-)) salts is unlikely. The roles of complexation with 18-Crown-6 and ion pair formation in the process of dissolution of Na(2)S(2)O(4) to methanol are discussed.

  16. Solid polymer electrolyte electrochemical storage cell containing a redox shuttle additive for overcharge protection

    Science.gov (United States)

    Richardson, Thomas J.; Ross, Philip N.

    1999-01-01

    A class of organic redox shuttle additives is described, preferably comprising nitrogen-containing aromatics compounds, which can be used in a high temperature (85.degree. C. or higher) electrochemical storage cell comprising a positive electrode, a negative electrode, and a solid polymer electrolyte to provide overcharge protection to the cell. The organic redox additives or shuttles are characterized by a high diffusion coefficient of at least 2.1.times.10.sup.-8 cm.sup.2 /second and a high onset potential of 2.5 volts or higher. Examples of such organic redox shuttle additives include an alkali metal salt of 1,2,4-triazole, an alkali metal salt of imidazole, 2,3,5,6-tetramethylpyrazine, 1,3,5-tricyanobenzene, and a dialkali metal salt of 3-4-dihydroxy-3-cyclobutene-1,2-dione.

  17. Vapor extractor

    Energy Technology Data Exchange (ETDEWEB)

    Bronder, G.A.; Bronder, L.R.

    1924-10-21

    A vapor extractor is described comprising a conveyer having compartments open at their top and bottom sides for a material to be conveyed, a plate forming a support for the conveyer and its compartments, means to move the conveyer over the plate with the material in the compartments, the movements of the conveyer forming ridges in the material that project above the walls of the compartments and means to remove the peaks of the ridges and thereby distribute the material composing the ridges into the bottom portion of the conveyer.

  18. Fabrication of solid state dye sensitized solar cells utilizing vapor phase polymerized poly(3,4-ethylenedioxythiophene) hole conducting layer

    Science.gov (United States)

    Skorenko, Kenneth H.

    There is a need for sustainable and renewable energy sources that can be used in both grid and off-grid structured systems. Photovoltaic devices have been used to generate electrical energy by capturing and converting photons from the sun. Dye sensitized solar cells (DSSC) have gained attention due to their consistent energy generation during indirect sunlight. Furthermore, DSSC can be applied as a flexible device and gain benefits from the low cost roll to roll manufacturing. With this in mind, we have taken steps toward optimizing a DSSC device for use as a solid state solar cell using conducting polymers. Typically DSSC use a liquid electrolyte as a hole conducting layer used to direct the separation of electron -- hole pairs. This liquid electrolyte comes with problems that can be subverted using conducting polymers. Poly(3,4 -- ethylenedioxythiophene) (PEDOT), is a conducting thiophene that is tailored to have enhanced conductivity. We show that a vapor phase polymerization (VPP) of PEDOT can be used as a hole conducting layer in a solid state DSSC device. To this end we have investigated the electrical properties of the VPP PEDOT films in order to understand how the morphology and conductive domains relate to a polymers conductivity. Using 4 point probe we have measure the sheet resistance of the film, as well as how the films resistance is altered during stress tests. Scanning electron microscopy has been utilized to compare morphologies of different PEDOT films and see how surface morphology impacts the conductance measured. Using conductive atomic force microscopy we can look at the conductive domains between VPP PEDOT and PEDOT:PSS films. We saw that conductive domains of the VPP PEDOT are not only more conductive but also much larger in size and widespread throughout the film. We show that there is formation of PEDOT through optical spectroscopy and structural characterization such as UV/Vis and Raman spectroscopy as well as X-ray diffraction. When

  19. 气相中碱金属离子与丝氨酸、亮氨酸和赖氨酸五肽复合物的裂解反应%Fragmentation Reactions of Complexes of Alkali Metal Ions with Pentaserine, Pentaleucine and Pentalysine in Gas Phase

    Institute of Scientific and Technical Information of China (English)

    魏王慧; 王青; 储艳秋; 汪日志; 丁传凡

    2014-01-01

    为了探索金属离子对含有不同侧链的多肽气相解离的影响,采用质谱法研究了碱金属离子Li+, Na+, K+, Rb+和Cs+分别与丝氨酸、亮氨酸和赖氨酸五肽(分别简写为S5, L5和K5)形成的复合物的裂解反应.质谱定性结果表明,5种碱金属离子均可以在气相中与丝氨酸、亮氨酸和赖氨酸五肽形成配合比为1:1和2:1的非共价复合物;竞争反应结果表明,随着碱金属离子半径的增加,它们与3种五肽的结合能力逐渐减弱.质谱定量结果表明, K+与丝氨酸、亮氨酸和赖氨酸五肽复合物的结合常数分别为8.94×104,2.83×104和2.50×103 L/mol,表明K+与五肽复合物的结合强度按照丝氨酸、亮氨酸和赖氨酸的顺序依次减小.含不同侧链碱金属离子-五肽复合物的碰撞诱导解离结果表明,复合物的碎裂主要发生在骨架上,丝氨酸五肽复合物最易碎裂,亮氨酸五肽复合物其次,赖氨酸五肽复合物则较难碎裂,且3种复合物的侧链断裂情况也呈现明显差异.此外,研究了Na+与亮氨酸五肽复合物所产生的碎片离子,分析了不同离子之间的来源关系,并以Dunbar的复合物理论模型为依据,推测在碎裂过程中,碱金属离子可能向五肽的碳端或氮端偏移.质谱碎片分析结果表明,在2:1的非共价复合物中,第一个碱金属离子与五肽上4个酰胺键的羰基结合,第二个碱金属离子与五肽的羧基氧原子结合.%For exploring the effects of alkali metal ions on the dissociations of peptides with different side chains in the gas phase, the complexes of Li+, Na+, K+, Rb+ and Cs+ with pentapeptides, Ser-Ser-Ser-Ser-Ser( S5 ) , Leu-Leu-Leu-Leu-Leu ( L5 ) and Lys-Lys-Lys-Lys-Lys ( K5 ) , were chosen to investigate the frag-mentation reaction pathways by mass spectrometry. The experimental results indicated that alkali metal ions and S5, L5, K5 can form 1:1 and 2:1 non-covalent complexes in the gas phase, and the binding

  20. Multimegawatt nuclear electric propulsion with gaseous and vapor core reactors with MHD

    Science.gov (United States)

    Knight, Travis; Anghaie, Samim; Smith, Blair; Houts, Michael

    2001-02-01

    This study investigated the development of a system concept for space power generation and nuclear electric propulsion based on a fissioning plasma core reactor (FPCR) with magnetohydrodynamic (MHD) power conversion system, coupled to a magnetoplasmadynamic (MPD) thruster. The FPCR is a liquid-vapor core reactor concept operating with metallic uranium or uranium tetrafluoride (UF4) vapor as the fissioning fuel and alkali metals or their fluorides as working fluid in a closed Rankine cycle with MHD energy conversion. Candidate working fluids include K, Li, Na, KF, LiF, NaF, etc. The system features core outlet temperatures of 3000 to 4000 K at pressures of about 1 to 10 MPa, MHD temperatures of 2000 to 3000 K, and radiator temperatures of 1200 to 2000 K. This combination of parameters offers the potential for low total system specific mass in the range of 0.4 to 0.6 kg/kWe. The MHD output could be coupled with minimal power conditioning to the variable specific impulse magnetoplasma rocket (VASIMR), MPD thrusters or other types of thruster for producing thrust at very high specific impulse (Isp=1500 to 10,000 s). .

  1. Effects of alkali metals on catalyst of MnOx-CeO2/ZrO2-PILC in the low-temperature selective catalytic reduction%碱土金属对MnOx-CeO2/ZrO2-PILC催化剂SCR活性影响研究

    Institute of Scientific and Technical Information of China (English)

    沈伯雄; 陈建宏; 姚燕; 胡国丽

    2012-01-01

    The poisoning effects of alkali metals on low-temperature selective catalytic reduction (SCR) catalyst MnOx-CeO2/ZrO2-PILC were invested by the method of impregnation in the laboratory. It was indicated that the addition of Ca/Mg would decrease the activities of the catalyst, and the poisoning effects were contacted with the amount and acidity of the doped-alkali metal. X-ray diffraction (XRD) , H2-temperature programmed reduction (H2-TPR) , N2 adsorption-desorption and temperature-programmed desorption of NH3(NH3-TPD) were used to characterize the properties of the fresh and alkali earth doped catalysts. According to the results, the doped-alkali metals would inhibit the reduction properties, induce the loss in surface area and surface acidity.%采用浸渍法模拟低温选择性催化还原(SCR)催化剂MnOx-CeO2/ZrO2-PILC的碱土金属中毒特性,研究了碱土金属及其负载量对中毒程度的影响.实验表明,钙/镁的添加会引起催化剂中毒,催化剂中毒失活程度与碱土金属的负载量有关.运用X射线衍射(XRD)、H2程序升温还原(H2-TPR)、氮气吸脱附及NH3程序升温脱附(NH3-TPD)对新鲜催化剂以及碱土金属中毒后的催化剂进行了表征.结果表明,钙/镁中毒后催化剂的比表面积降低、催化剂氧化还原性和表面酸性减少,进而造成催化剂失活.

  2. A facile, solvent vapor-fumigation-induced, self-repair recrystallization of CH3NH3PbI3 films for high-performance perovskite solar cells.

    Science.gov (United States)

    Zhu, Weidong; Yu, Tao; Li, Faming; Bao, Chunxiong; Gao, Hao; Yi, Yong; Yang, Jie; Fu, Gao; Zhou, Xiaoxin; Zou, Zhigang

    2015-03-12

    A high-quality CH3NH3PbI3 film is crucial in the manufacture of a high-performance perovskite solar cell. Here, a recrystallization process via facile fumigation with DMF vapor has been successfully introduced to self-repair of CH3NH3PbI3 films with poor coverage and low crystallinity prepared by the commonly used one-step spin-coating method. We found that the CH3NH3PbI3 films with dendritic structures can spontaneously transform to the uniform ones with full coverage and high crystallinity by adjusting the cycles of the recrystallization process. The mesostructured perovskite solar cells based on these repaired CH3NH3PbI3 films showed reproducible optimal power conversion efficiency (PCE) of 11.15% and average PCE of 10.25±0.90%, which are much better than that of devices based on the non-repaired CH3NH3PbI3 films. In addition, the hysteresis phenomenon in the current-voltage test can also be effectively alleviated due to the quality of the films being improved in the optimized devices. Our work proved that the fumigation of solvent vapor can modify metal organic perovskite films such as CH3NH3PbI3. It offers a novel and attractive way to fabricate high-performance perovskite solar cells.

  3. Effusion Cell Measurements of the Vapor Pressure of Cobalt at Temperatures up to 2000K; Comparisons with Iron and Nickel

    Science.gov (United States)

    Nuth, J. A.; Ferguson, F. T.; Johnson, N. M.

    2004-01-01

    It has become increasingly clear over the past decade that high temperature processes played important roles in the Primitive Solar Nebula. Unfortunately, basic data, such as the vapor pressures of Fe, Ni, Co or SiO have not been measured over the appropriate temperature range (near T approx. 2000K), but must be extrapolated from lower temperature measurements often made more than 50 years ago. The extrapolation of the available data to higher temperatures can be quite complex (e.g., see [1] for SiO vapor pressures) and can depend on other factors such as the oxygen fugacity or the presence of hydrogen gas not accounted for in the original measurements. Moreover, modern technology has made possible more accurate measurements of such quantities over a wider temperature range. We have acquired a commercial Thermo-Cahn Thermogravimetric system capable of vacuum operation to 1700C and measurement of a 10g change in sample mass using up to a 100g sample, with microgram accuracy. With this new system we have initiated a series of basic vapor pressure measurements on simple metals such as Fe[2] and Ni[3] with the intention to extend such measurements to more complex systems once we gain sufficient experience.

  4. Precise measurements of 203 Tl and 205 Tl excited state hyperfine splittings and isotope shifts using two-step vapor cell spectroscopy

    Science.gov (United States)

    Majumder, P. K.; Cheng, Sau Man; Rupasinghe, P. M.

    2016-05-01

    We have undertaken a series of high-precision atomic structure measurement in thallium to test ongoing ab initio atomic structure calculations of relevance to symmetry violation tests in this element. We are currently completing two-step spectroscopy measurements of the 8P1 / 2 and 8P3 / 2 hyperfine structure and isotope shift using a heated thallium vapor cell and two external cavity semiconductor diode lasers. One laser, locked to the thallium 6P1 / 2 --> 7S1 / 2 378 nm transition excites one or both naturally-occurring isotopes to an intermediate state. A second red laser overlaps the UV beam within the thallium vapor cell in both a co-propagating and counter-propagating configuration. Analysis of subsequent Doppler-free absorption spectra of the 7S1 / 2 --> 8P1 / 2 , 3 / 2 visible transitions allows us to extract both hyperfine and isotope shift information for these excited states with uncertainties below 1 MHz. Frequency modulation of the red laser provides convenient in situ frequency calibration. Recent measurements in our group have shown significant discrepancies from older hyperfine structure measurements in thallium excited states. Current results will be presented. Work supported by NSF Grant # 1404206.

  5. Research Update: Hybrid organic-inorganic perovskite (HOIP) thin films and solar cells by vapor phase reaction

    Science.gov (United States)

    Shen, Po-Shen; Chiang, Yu-Hsien; Li, Ming-Hsien; Guo, Tzung-Fang; Chen, Peter

    2016-09-01

    With the rapid progress in deposition techniques for hybrid organic-inorganic perovskite (HOIP) thin films, this new class of photovoltaic (PV) technology has achieved material quality and power conversion efficiency comparable to those established technologies. Among the various techniques for HOIP thin films preparation, vapor based deposition technique is considered as a promising alternative process to substitute solution spin-coating method for large-area or scale-up preparation. This technique provides some unique benefits for high-quality perovskite crystallization, which are discussed in this research update.

  6. Research Update: Hybrid organic-inorganic perovskite (HOIP thin films and solar cells by vapor phase reaction

    Directory of Open Access Journals (Sweden)

    Po-Shen Shen

    2016-09-01

    Full Text Available With the rapid progress in deposition techniques for hybrid organic-inorganic perovskite (HOIP thin films, this new class of photovoltaic (PV technology has achieved material quality and power conversion efficiency comparable to those established technologies. Among the various techniques for HOIP thin films preparation, vapor based deposition technique is considered as a promising alternative process to substitute solution spin-coating method for large-area or scale-up preparation. This technique provides some unique benefits for high-quality perovskite crystallization, which are discussed in this research update.

  7. Characterization of electrochemical photovoltaic cells using polycrystalline CdSe and CdTe electrodes grown by a liquid metal-vapor reaction

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Z.; Cinquino, M.; Lawrence, M.F. (Laboratories for Inorganic Materials, Department of Chemistry and Biochemistry, Concordia University, 1455 De Maisonneuve Bld. West, Montreal, Quebec, Canada H3G 1M8 (CA))

    1991-06-01

    Polycrystalline CdSe and CdTe layers were fabricated by putting liquid Cd in contact with Se or Te vapors under constant Ar flow. The crystalline structure, surface properties, and semiconducting properties of these materials have been determined. Both materials were found to be {ital n}-type semiconductors. The results show that, under the proper experimental conditions, the liquid metal-vapor reaction enables the synthesis of polycrystalline CdSe photoelectrodes with a 6.9% energy conversion efficiency when used in an electrochemical photovoltaic cell under 80 mW/cm{sup 2} of white light illumination. This efficiency rates amongst the highest ones measured under similar conditions using polycrystalline CdSe. These CdSe layers have a majority charge carrier density of {ital N}{sub {ital D}}=2.6{times}10{sup 17} cm{sup {minus}3} and possess a highly textured surface which is assumed to be mainly responsible for the high photovoltaic efficiency. The highly textured CdTe samples obtained by this process, however, show a photovoltaic conversion efficiency of only 0.2%, and this is seen to be mainly due to their high majority charge carrier density of {ital N}{sub {ital D}}=7.8{times}10{sup 19} cm{sup {minus}3}.

  8. Improved efficiency of a large-area Cu(In,Ga)Se₂ solar cell by a nontoxic hydrogen-assisted solid Se vapor selenization process.

    Science.gov (United States)

    Wu, Tsung-Ta; Hu, Fan; Huang, Jyun-Hong; Chang, Chia-ho; Lai, Chih-chung; Yen, Yu-Ting; Huang, Hou-Ying; Hong, Hwen-Fen; Wang, Zhiming M; Shen, Chang-Hong; Shieh, Jia-Min; Chueh, Yu-Lun

    2014-04-01

    A nontoxic hydrogen-assisted solid Se vapor selenization process (HASVS) technique to achieve a large-area (40 × 30 cm(2)) Cu(In,Ga)Se2 (CIGS) solar panel with enhanced efficiencies from 7.1 to 10.8% (12.0% for active area) was demonstrated. The remarkable improvement of efficiency and fill factor comes from improved open circuit voltage (Voc) and reduced dark current due to (1) decreased interface recombination raised from the formation of a widened buried homojunction with n-type Cd(Cu) participation and (2) enhanced separation of electron and hole carriers resulting from the accumulation of Na atoms on the surface of the CIGS film. The effects of microstructural, compositional, and electrical characteristics with hydrogen-assisted Se vapor selenization, including interdiffusion of atoms and formation of buried homojunction, were examined in detail. This methodology can be also applied to CIS (CuInSe2) thin film solar cells with enhanced efficiencies from 5.3% to 8.5% (9.4% for active area) and provides a facile approach to improve quality of CIGS and stimulate the nontoxic progress in the large scale CIGS PV industry.

  9. Characterization of electrochemical photovoltaic cells using polycrystalline CdSe and CdTe electrodes grown by a liquid metal-vapor reaction

    International Nuclear Information System (INIS)

    Polycrystalline CdSe and CdTe layers were fabricated by putting liquid Cd in contact with Se or Te vapors under constant Ar flow. The crystalline structure, surface properties, and semiconducting properties of these materials have been determined. Both materials were found to be n-type semiconductors. The results show that, under the proper experimental conditions, the liquid metal-vapor reaction enables the synthesis of polycrystalline CdSe photoelectrodes with a 6.9% energy conversion efficiency when used in an electrochemical photovoltaic cell under 80 mW/cm2 of white light illumination. This efficiency rates amongst the highest ones measured under similar conditions using polycrystalline CdSe. These CdSe layers have a majority charge carrier density of ND=2.6x1017 cm-3 and possess a highly textured surface which is assumed to be mainly responsible for the high photovoltaic efficiency. The highly textured CdTe samples obtained by this process, however, show a photovoltaic conversion efficiency of only 0.2%, and this is seen to be mainly due to their high majority charge carrier density of ND=7.8x1019 cm-3

  10. Effects of Yamase climatic condition during the pollen mother cell developmental stage on concentrations of Cs and Sr in brown rice

    International Nuclear Information System (INIS)

    Effects of the Yamase climatic condition on the concentration of alkali metals and alkaline earth metals in brown rice were examined in relation to the soil-to-plant transfer factors of 137Cs and 90Sr. Rice plants (Oryza sativa L cv. Yumeakari) were cultivated in an artificial climate chamber, and exposed to a simulated Yamase condition for 3 or 7 d during the pollen mother cell developmental stage. In these simulated treatments, temperature and light intensity were set to 5degC lower and 50% lower than the respective control values. Fog was generated with visibility of 70±30 m. Concentrations of alkali metals, alkaline earth metals and the other minor elements in brown rice samples were analyzed. Measured Cs and Sr concentrations were found to be unaffected by the Yamase treatments, while concentrations of Fe, Cu, Zn and Mo were increased. (author)

  11. Simple-design ultra-low phase noise microwave frequency synthesizers for high-performing Cs and Rb vapor-cell atomic clocks

    International Nuclear Information System (INIS)

    We report on the development and characterization of novel 4.596 GHz and 6.834 GHz microwave frequency synthesizers devoted to be used as local oscillators in high-performance Cs and Rb vapor-cell atomic clocks. The key element of the synthesizers is a custom module that integrates a high spectral purity 100 MHz oven controlled quartz crystal oscillator frequency-multiplied to 1.6 GHz with minor excess noise. Frequency multiplication, division, and mixing stages are then implemented to generate the exact output atomic resonance frequencies. Absolute phase noise performances of the output 4.596 GHz signal are measured to be −109 and −141 dB rad2/Hz at 100 Hz and 10 kHz Fourier frequencies, respectively. The phase noise of the 6.834 GHz signal is −105 and −138 dB rad2/Hz at 100 Hz and 10 kHz offset frequencies, respectively. The performances of the synthesis chains contribute to the atomic clock short term fractional frequency stability at a level of 3.1 × 10−14 for the Cs cell clock and 2 × 10−14 for the Rb clock at 1 s averaging time. This value is comparable with the clock shot noise limit. We describe the residual phase noise measurements of key components and stages to identify the main limitations of the synthesis chains. The residual frequency stability of synthesis chains is measured to be at the 10−15 level for 1 s integration time. Relevant advantages of the synthesis design, using only commercially available components, are to combine excellent phase noise performances, simple-architecture, low-cost, and to be easily customized for signal output generation at 4.596 GHz or 6.834 GHz for applications to Cs or Rb vapor-cell frequency standards

  12. Simple-design ultra-low phase noise microwave frequency synthesizers for high-performing Cs and Rb vapor-cell atomic clocks

    Energy Technology Data Exchange (ETDEWEB)

    François, B. [FEMTO-ST, CNRS, Université de Franche-Comté, 26 chemin de l’Epitaphe, 25030 Besançon (France); INRIM, Strada delle Cacce 91, 10135 Torino (Italy); Calosso, C. E.; Micalizio, S. [INRIM, Strada delle Cacce 91, 10135 Torino (Italy); Abdel Hafiz, M.; Boudot, R. [FEMTO-ST, CNRS, Université de Franche-Comté, 26 chemin de l’Epitaphe, 25030 Besançon (France)

    2015-09-15

    We report on the development and characterization of novel 4.596 GHz and 6.834 GHz microwave frequency synthesizers devoted to be used as local oscillators in high-performance Cs and Rb vapor-cell atomic clocks. The key element of the synthesizers is a custom module that integrates a high spectral purity 100 MHz oven controlled quartz crystal oscillator frequency-multiplied to 1.6 GHz with minor excess noise. Frequency multiplication, division, and mixing stages are then implemented to generate the exact output atomic resonance frequencies. Absolute phase noise performances of the output 4.596 GHz signal are measured to be −109 and −141 dB rad{sup 2}/Hz at 100 Hz and 10 kHz Fourier frequencies, respectively. The phase noise of the 6.834 GHz signal is −105 and −138 dB rad{sup 2}/Hz at 100 Hz and 10 kHz offset frequencies, respectively. The performances of the synthesis chains contribute to the atomic clock short term fractional frequency stability at a level of 3.1 × 10{sup −14} for the Cs cell clock and 2 × 10{sup −14} for the Rb clock at 1 s averaging time. This value is comparable with the clock shot noise limit. We describe the residual phase noise measurements of key components and stages to identify the main limitations of the synthesis chains. The residual frequency stability of synthesis chains is measured to be at the 10{sup −15} level for 1 s integration time. Relevant advantages of the synthesis design, using only commercially available components, are to combine excellent phase noise performances, simple-architecture, low-cost, and to be easily customized for signal output generation at 4.596 GHz or 6.834 GHz for applications to Cs or Rb vapor-cell frequency standards.

  13. Self-generating magnetometer with laser pumping employment in “end resonance” wall coated vapor cell atomic clocks

    Science.gov (United States)

    Baranov, A. A.; Ermak, S. V.; Smolin, R. V.; Semenov, V. V.

    2016-06-01

    This paper presents the results of two double resonance signals correlation investigation. These signals were observed synchronously in optically oriented Rb87 vapors with laser pumping in a dual scheme: low frequency Mx-magnetometer and microwave frequency discriminator. Analytical studies of the scalar and vector light shift components contribution to the frequency instability of the end resonance microwave transitions are presented. An experimental demonstration of the light shift components mutual compensation in optically pumped Rb87 atoms was provided. The results were processed in terms of Allan variance, which demonstrated an effect of decreasing frequency variation at averaging times more than 100 s for a joint scheme of the end resonance microwave transition and selfgenerating (Mx) magnetometer.

  14. Vapors produced by electronic cigarettes and e-juices with flavorings induce toxicity, oxidative stress, and inflammatory response in lung epithelial cells and in mouse lung.

    Science.gov (United States)

    Lerner, Chad A; Sundar, Isaac K; Yao, Hongwei; Gerloff, Janice; Ossip, Deborah J; McIntosh, Scott; Robinson, Risa; Rahman, Irfan

    2015-01-01

    Oxidative stress and inflammatory response are the key events in the pathogenesis of chronic airway diseases. The consumption of electronic cigarettes (e-cigs) with a variety of e-liquids/e-juices is alarmingly increasing without the unrealized potential harmful health effects. We hypothesized that electronic nicotine delivery systems (ENDS)/e-cigs pose health concerns due to oxidative toxicity and inflammatory response in lung cells exposed to their aerosols. The aerosols produced by vaporizing ENDS e-liquids exhibit oxidant reactivity suggesting oxidants or reactive oxygen species (OX/ROS) may be inhaled directly into the lung during a "vaping" session. These OX/ROS are generated through activation of the heating element which is affected by heating element status (new versus used), and occurs during the process of e-liquid vaporization. Unvaporized e-liquids were oxidative in a manner dependent on flavor additives, while flavors containing sweet or fruit flavors were stronger oxidizers than tobacco flavors. In light of OX/ROS generated in ENDS e-liquids and aerosols, the effects of ENDS aerosols on tissues and cells of the lung were measured. Exposure of human airway epithelial cells (H292) in an air-liquid interface to ENDS aerosols from a popular device resulted in increased secretion of inflammatory cytokines, such as IL-6 and IL-8. Furthermore, human lung fibroblasts exhibited stress and morphological change in response to treatment with ENDS/e-liquids. These cells also secrete increased IL-8 in response to a cinnamon flavored e-liquid and are susceptible to loss of cell viability by ENDS e-liquids. Finally, exposure of wild type C57BL/6J mice to aerosols produced from a popular e-cig increase pro-inflammatory cytokines and diminished lung glutathione levels which are critical in maintaining cellular redox balance. Thus, exposure to e-cig aerosols/juices incurs measurable oxidative and inflammatory responses in lung cells and tissues that could lead to

  15. Vapors produced by electronic cigarettes and e-juices with flavorings induce toxicity, oxidative stress, and inflammatory response in lung epithelial cells and in mouse lung.

    Directory of Open Access Journals (Sweden)

    Chad A Lerner

    Full Text Available Oxidative stress and inflammatory response are the key events in the pathogenesis of chronic airway diseases. The consumption of electronic cigarettes (e-cigs with a variety of e-liquids/e-juices is alarmingly increasing without the unrealized potential harmful health effects. We hypothesized that electronic nicotine delivery systems (ENDS/e-cigs pose health concerns due to oxidative toxicity and inflammatory response in lung cells exposed to their aerosols. The aerosols produced by vaporizing ENDS e-liquids exhibit oxidant reactivity suggesting oxidants or reactive oxygen species (OX/ROS may be inhaled directly into the lung during a "vaping" session. These OX/ROS are generated through activation of the heating element which is affected by heating element status (new versus used, and occurs during the process of e-liquid vaporization. Unvaporized e-liquids were oxidative in a manner dependent on flavor additives, while flavors containing sweet or fruit flavors were stronger oxidizers than tobacco flavors. In light of OX/ROS generated in ENDS e-liquids and aerosols, the effects of ENDS aerosols on tissues and cells of the lung were measured. Exposure of human airway epithelial cells (H292 in an air-liquid interface to ENDS aerosols from a popular device resulted in increased secretion of inflammatory cytokines, such as IL-6 and IL-8. Furthermore, human lung fibroblasts exhibited stress and morphological change in response to treatment with ENDS/e-liquids. These cells also secrete increased IL-8 in response to a cinnamon flavored e-liquid and are susceptible to loss of cell viability by ENDS e-liquids. Finally, exposure of wild type C57BL/6J mice to aerosols produced from a popular e-cig increase pro-inflammatory cytokines and diminished lung glutathione levels which are critical in maintaining cellular redox balance. Thus, exposure to e-cig aerosols/juices incurs measurable oxidative and inflammatory responses in lung cells and tissues that

  16. A CPT-based Cs vapor cell atomic clock with a short-term fractional frequency stability of 3 x 10-13 τ-1/2

    Science.gov (United States)

    Abdel Hafiz, Moustafa; Liu, Xiaochi; Guérandel, Stéphane; De Clercq, Emeric; Boudot, Rodolphe

    2016-06-01

    This article reports on the development and short-term fractional frequency stability of a continuous-regime (CW) Cs vapor cell atomic clock based on coherent population trapping (CPT). The push-pull optical pumping technique is used to increase the number of atoms that participate to the clock transition, yielding a typical CPT resonance contrast of 25% for a CPT linewidth of about 450 Hz. The clock short-term fractional frequency stability is measured to be 3 x 10-13 τ-1/2 up to 100 seconds averaging time, in correct agreement with the signal-to-noise ratio limit. The mid-term frequency stability results are currently mainly limited by laser power effects. The detection of high-contrast narrow Raman-Ramsey fringes is demonstrated with this setup by making the atoms interact with a light pulse sequence.

  17. Humid environment stability of low pressure chemical vapor deposited boron doped zinc oxide used as transparent electrodes in thin film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Steinhauser, Jerome, E-mail: jerome.steinhauser@oerlikon.com [Institute of Microtechnology (IMT), University of Neuchatel, CH-2000 Neuchatel (Switzerland); Meyer, Stefan; Schwab, Marlene; Fay, Sylvie; Ballif, Christophe [Institute of Microtechnology (IMT), University of Neuchatel, CH-2000 Neuchatel (Switzerland); Kroll, U.; Borrello, D. [Oerlikon Solar-Lab, 2000 Neuchatel (Switzerland)

    2011-10-31

    The stability in humid environment of low pressure chemical vapor deposited boron doped zinc oxide (LPCVD ZnO:B) used as transparent conductive oxide in thin film silicon solar cells is investigated. Damp heat treatment (exposure to humid and hot atmosphere) induces a degradation of the electrical properties of unprotected LPCVD ZnO:B layers. By combining analyses of the electrical and optical properties of the films, we are able to attribute this behavior to an increase of electron grain boundary scattering. This is in contrast to the intragrain scattering mechanisms, which are not affected by damp heat exposure. The ZnO stability is enhanced for heavily doped films due to easier tunneling through potential barrier at grain boundaries.

  18. Ecofriendly and Nonvacuum Electrostatic Spray-Assisted Vapor Deposition of Cu(In,Ga)(S,Se)2 Thin Film Solar Cells.

    Science.gov (United States)

    Hossain, Md Anower; Wang, Mingqing; Choy, Kwang-Leong

    2015-10-14

    Chalcopyrite Cu(In,Ga)(S,Se)2 (CIGSSe) thin films have been deposited by a novel, nonvacuum, and cost-effective electrostatic spray-assisted vapor deposition (ESAVD) method. The generation of a fine aerosol of precursor solution, and their controlled deposition onto a molybdenum substrate, results in adherent, dense, and uniform Cu(In,Ga)S2 (CIGS) films. This is an essential tool to keep the interfacial area of thin film solar cells to a minimum value for efficient charge separation as it helps to achieve the desired surface smoothness uniformity for subsequent cadmium sulfide and window layer deposition. This nonvacuum aerosol based approach for making the CIGSSe film uses environmentally benign precursor solution, and it is cheaper for producing solar cells than that of the vacuum-based thin film solar technology. An optimized CIGSSe thin film solar cell with a device configuration of molybdenum-coated soda-lime glass substrate/CIGSSe/CdS/i-ZnO/AZO shows the photovoltaic (j-V) characteristics of Voc=0.518 V, jsc=28.79 mA cm(-2), fill factor=64.02%, and a promising power conversion efficiency of η=9.55% under simulated AM 1.5 100 mW cm(-2) illuminations, without the use of an antireflection layer. This demonstrates the potential of ESAVD deposition as a promising alternative approach for making thin film CIGSSe solar cells at a lower cost. PMID:26390182

  19. Microscopically controlled surgical excision combined with ultrapulse CO2 vaporization in the management of a patient with the nevoid basal cell carcinoma syndrome.

    Science.gov (United States)

    Krunic, A L; Viehman, G E; Madani, S; Clark, R E

    1998-01-01

    Nevoid basal cell carcinoma syndrome is an autosomal dominant condition characterized by multiple basal cell carcinomas, skeletal abnormalities and sometimes mental retardation. The large number of tumors, which are often disfiguring, presents extreme difficulties in the treatment of these patients. Microscopically controlled excision, compared to other modalities (radiation therapy, photodynamic therapy, intralesional interferon alpha-2b) offers the highest cure rate. However, because of the large size and involvement of wide areas of the skin, this approach is sometimes impractical. The ultrapulse CO2 laser with high energy and short pulses achieves char-free ablation of the tumors, bloodless surgical field, minimal nonspecific thermal damage, rapid healing and diminished postoperative pain. Also, a number of lesions can be removed in a single session. We present a 48-year-old man with a 6.5 x 4.5 cm large basal cell carcinoma involving the anterior abdomen and navel area. The central thick portion of the tumor was resected by microscopically controlled excision with 3 stages, and wide thinner peripheral crescentic plaque vaporized with ultrapulse CO2 laser. The laser settings were 300 mJ energy/pulse and 100 W average power, which corresponds to the fluence of 7.5 J/cm2. Computerized pattern generator (ultrascan handpiece) was adjusted to patterns of 3 (circle) and 1 (square) with sizes varying from 5 to 7, and density of 9 (60% overlapping). The tumor was vaporized with 6 passes, all the way to deep reticular dermis. A fifteen month-follow up disclosed no recurrent disease. Subsequent biopsies revealed only a scar with postinflammatory hyperpigmentation. Our experience indicates that combined treatment with microscopically controlled excision and ultrapulse CO2 laser ablation is a suitable modality for the large tumor plaques involving concave and convex areas of the skin respectively. Microscopically controlled excision of thicker, concave portions of basal

  20. Detection of slow atoms confined in a Cesium vapor cell by spatially separated pump and probe laser beams

    CERN Document Server

    Todorov, Petko; Maurin, Isabelle; Saltiel, Solomon; Bloch, Daniel

    2013-01-01

    The velocity distribution of atoms in a thermal gas is usually described through a Maxwell-Boltzman distribution of energy, and assumes isotropy. As a consequence, the probability for an atom to leave the surface under an azimuth angle {\\theta} should evolve as cos {\\theta}, in spite of the fact that there is no microscopic basis to justify such a law. The contribution of atoms moving at a grazing incidence towards or from the surface, i.e. atoms with a small normal velocity, here called "slow" atoms, reveals essential in the development of spectroscopic methods probing a dilute atomic vapor in the vicinity of a surface, enabling a sub-Doppler resolution under a normal incidence irradiation. The probability for such "slow" atoms may be reduced by surface roughness and atom-surface interaction. Here, we describe a method to observe and to count these slow atoms relying on a mechanical discrimination, through spatially separated pump and probe beams. We also report on our experimental progresses toward such a g...

  1. Thermodynamics Study of Effects of Alkali Metals on Mercury Transformation During Co-combustion of Biomass With Coal%生物质与煤混燃过程中碱金属对汞氧化影响的热力学研究

    Institute of Scientific and Technical Information of China (English)

    余婉璇; 刁永发; 沈恒

    2012-01-01

    针对生物质中C1和碱金属含量高的特点,研究生物质与煤混燃过程中Hg的氧化机制.使用化学热力学软件Chemical Equilibrium with Applications(CEA)建立C/H/O/N/S/C1/K/Na模型,分析碱金属元素K、Na与非金属元素Cl和S的反应,发现1 100K以下Cl仍然主要以HCl形式存在,SO2的含量逐渐减少,碱金属主要以碱金属硫酸盐(A2SO4)的形式存在,这对Hg的氧化反应变得更为有利,同时随着生物质的添加,这种趋势更为明显.同时使用动力学软件Chemkin4.1构建了Hg/C/H/O/N/S/C1/K/Na的化学和气相平衡模型,进一步研究了生物质与煤混燃过程中对Hg氧化的影响.计算结果表明,生物质与煤之比越高,对Hg的氧化越有利,生物质中高含量的C1是促进Hg氧化最主要的因素,而K、Na的存在对Hg的氧化有进一步的促进作用,这进一步证实了热力学计算结果.%The oxidation mechanism of mercury during co-combustion biomass with coal was studied because of the high content of Cl and alkali metal of the biomass. C/H/O/N/S/ Cl/K/Na model was established with chemical thermodynamics software CEA, and the interaction between alkali metals and chlorine or sulfur were analyzed. It is founded that below 1 100K, Cl is still mainly in the form of HC1, the content of SO2 decreases, and the alkali metals exist in the form of alkali sulfate (A2SO4), which will contribute to the oxidation of Hg. And with the addition of biomass, this trend becomes more apparent. Hg/C/H/O/N/S/Cl/Hg/K/Na chemical and phase equilibrium model was established based on previous studies with CHEMKIN 4.1, and the effect of biomass co-firing with coal on Hg oxidation was further studied. Chemical and phase equilibrium calculations results show that the more the ratio of biomass and coal is, the better the oxidation of Hg. The high content of Cl in the biomass is the most important factor to promote Hg oxidation, and the presence of K and Na will further promote Hg oxidation

  2. Development of carbon nanotubes based gas diffusion layers by in situ chemical vapor deposition process for proton exchange membrane fuel cells

    Science.gov (United States)

    Kannan, A. M.; Kanagala, P.; Veedu, V.

    A proprietary in situ chemical vapor deposition (CVD) process was developed for gas diffusion layer (GDL) by growing a micro-porous layer on the macro-porous, non-woven fibrous carbon paper. The characteristics of the GDL samples such as, surface morphology, wetting characteristics, and cross-section were characterized using electron microscopes, goniometer and focused ion beam, respectively. Fuel cell performance of the GDLs was evaluated using single cell with hydrogen/oxygen as well as hydrogen/air at ambient pressure, at elevated temperature and various RH conditions using Nafion-212 as an electrolyte. The GDLs with in situ growth of micro-porous layers containing carbon nanotubes (CNTs) without any hydrophobic agent showed significant improvement in mechanical robustness as well as fuel cell performance at elevated temperature at lower RH conditions. The micro-porous layer of the GDLs as seen under scanning electron microscope showed excellent surface morphology with surface homogeneity through reinforcement by the multi-walled CNTs.

  3. Performance Improvement of Microcrystalline p-SiC/i-Si/n-Si Thin Film Solar Cells by Using Laser-Assisted Plasma Enhanced Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Hsin-Ying Lee

    2014-01-01

    Full Text Available The microcrystalline p-SiC/i-Si/n-Si thin film solar cells treated with hydrogen plasma were fabricated at low temperature using a CO2 laser-assisted plasma enhanced chemical vapor deposition (LAPECVD system. According to the micro-Raman results, the i-Si films shifted from 482 cm−1 to 512 cm−1 as the assisting laser power increased from 0 W to 80 W, which indicated a gradual transformation from amorphous to crystalline Si. From X-ray diffraction (XRD results, the microcrystalline i-Si films with (111, (220, and (311 diffraction were obtained. Compared with the Si-based thin film solar cells deposited without laser assistance, the short-circuit current density and the power conversion efficiency of the solar cells with assisting laser power of 80 W were improved from 14.38 mA/cm2 to 18.16 mA/cm2 and from 6.89% to 8.58%, respectively.

  4. Amorphous silicon carbonitride diaphragm for environmental-cell transmission electron microscope fabricated by low-energy ion beam induced chemical vapor deposition

    Science.gov (United States)

    Matsutani, Takaomi; Yamasaki, Kayo; Imaeda, Norihiro; Kawasaki, Tadahiro

    2015-12-01

    An amorphous silicon carbonitride (a-SiCN) diaphragm for an environmental-cell transmission electron microscope (E-TEM) was fabricated by low-energy ion beam induced chemical vapor deposition (LEIBICVD) with hexamethyldisilazane (HMDSN). The films were prepared by using gaseous HMDSN and N2+ ions with energies ranging from 300 to 600 eV. The diaphragms were applied to Si (1 0 0) and a Cu grid with 100-μm-diameter holes. With increasing ion energy, these diaphragms became perfectly smooth surfaces (RMS = 0.43 nm at 600 eV), as confirmed by atomic force microscopy and TEM. The diaphragms were amorphous and transparent to 200 kV electrons, and no charge-up was observed. Fourier transform infrared spectra and X-ray photoelectron spectra revealed that the elimination of organic compounds and formation of Si-N and C-N bonds can be promoted in diaphragms by increasing the ion impact energy. The resistance to electron beams and reaction gases in the E-cell was improved when the diaphragm was formed with high ion energy.

  5. The Growth of InGaAsN for High Efficiency Solar Cells by Metalorganic Chemical Vapor Deposition

    International Nuclear Information System (INIS)

    InGaAsN alloys are a promising material for increasing the efficiency of multi-junction solar cells now used for satellite power systems. However, the growth of these dilute N containing alloys has been challenging with further improvements in material quality needed before the solar cell higher efficiencies are realized. Nitrogen/V ratios exceeding 0.981 resulted in lower N incorporation and poor surface morphologies. The growth rate was found to depend on not only the total group III transport for a fixed N/V ratio but also on the N/V ratio. Carbon tetrachloride and dimethylzinc were effective for p-type doping. Disilane was not an effective n-type dopant while SiCl4 did result in n-type material but only a narrow range of electron concentrations (2-5e17cm(sup -3)) were achieved

  6. Improving low pressure chemical vapor deposited zinc oxide contacts for thin film silicon solar cells by using rough glass substrates

    Energy Technology Data Exchange (ETDEWEB)

    Steinhauser, J., E-mail: jerome.steinhauser@oerlikon.com; Boucher, J.-F.; Omnes, E.; Borrello, D.; Vallat-Sauvain, E.; Monteduro, G.; Marmelo, M.; Orhan, J.-B.; Wolf, B.; Bailat, J.; Benagli, S.; Meier, J.; Kroll, U.

    2011-12-01

    Compared to zinc oxide grown (ZnO) on flat glass, rough etched glass substrates decrease the sheet resistance (R{sub sq}) of zinc oxide layers grown on it. We explain this R{sub sq} reduction from a higher thickness and an improved electron mobility for ZnO layers deposited on rough etched glass substrates. When using this etched glass substrate, we also obtain a large variety of surface texture by changing the thickness of the ZnO layer grown on it. This new combination of etched glass and ZnO layer shows improved light trapping potential compared to ZnO films grown on flat glass. With this new approach, Micromorph thin film silicon tandem solar cells with high total current densities (sum of the top and bottom cell current density) of up to 26.8 mA cm{sup -2} were fabricated.

  7. The large-area CdTe thin film for CdS/CdTe solar cell prepared by physical vapor deposition in medium pressure

    Science.gov (United States)

    Luo, Run; Liu, Bo; Yang, Xiaoyan; Bao, Zheng; Li, Bing; Zhang, Jingquan; Li, Wei; Wu, Lili; Feng, Lianghuan

    2016-01-01

    The Cadmium telluride (CdTe) thin film has been prepared by physical vapor deposition (PVD), the Ar + O2 pressure is about 0.9 kPa. This method is a newer technique to deposit CdTe thin film in large area, and the size of the film is 30 × 40 cm2. This method is much different from the close-spaced sublimation (CSS), as the relevance between the source temperature and the substrate temperature is weak, and the gas phase of CdTe is transferred to the substrate by Ar + O2 flow. Through this method, the compact and uniform CdTe film (30 × 40 cm2) has been achieved, and the performances of the CdTe thin film have been determined by transmission spectrum, SEM and XRD. The film is observed to be compact with a good crystallinity, the CdTe is polycrystalline with a cubic structure and a strongly preferred (1 1 1) orientation. Using the CdTe thin film (3 × 5 cm2) which is taken from the deposited large-area film, the 14.6% efficiency CdS/CdTe thin film solar cell has been prepared successfully. The structure of the cell is glass/FTO/CdS/CdTe/graphite slurry/Au, short circuit current density (Jsc) of the cell is 26.9 mA/cm2, open circuit voltage (Voc) is 823 mV, and filling factor (FF) is 66.05%. This technique can be a quite promising method to apply in the industrial production, as it has great prospects in the fabricating of large-area CdTe film.

  8. Stratospheric water vapor feedback

    OpenAIRE

    A. E. Dessler; Schoeberl, M. R.; Wang, T.; S. M. Davis; K. H. Rosenlof

    2013-01-01

    We show observational evidence for a stratospheric water vapor feedback—a warmer climate increases stratospheric water vapor, and because stratospheric water vapor is itself a greenhouse gas, this leads to further warming. An estimate of its magnitude from a climate model yields a value of +0.3 W/(m2⋅K), suggesting that this feedback plays an important role in our climate system.

  9. Series of Multifluorine Substituted Oligomers for Organic Solar Cells with Efficiency over 9% and Fill Factor of 0.77 by Combination Thermal and Solvent Vapor Annealing.

    Science.gov (United States)

    Wang, Jin-Liang; Liu, Kai-Kai; Yan, Jun; Wu, Zhuo; Liu, Feng; Xiao, Fei; Chang, Zheng-Feng; Wu, Hong-Bin; Cao, Yong; Russell, Thomas P

    2016-06-22

    We report the synthesis of a family of multifluorine substituted oligomers and the corresponding polymer that have the same backbones but different conjugation lengths and amounts of fluorine atoms on the backbone. The physical properties and photovoltaic performances of these materials were systematically investigated using optical absorption, charge mobility, atomic force microscopy, transmission electron microscopy, grazing incidence X-ray diffraction, resonant soft X-ray scattering methods, and photovoltaic devices. The power conversion efficiencies (PCEs) based on oligomers were much higher than that in the polymer. Moreover, the devices based on BIT6F and BIT10F, which have an axisymmetric electron-deficient difluorobenzothiadiazole as the central unit, gave slightly higher PCEs than those with centrosymmetric electron-rich indacenodithiophene (IDT) as the central unit (BIT4F or BIT8F). Using proper solvent vapor annealing (SVA), particularly using thermal annealing (TA) followed by SVA, the device performance could be significantly improved. Notably, the best PCE of 9.1% with a very high FF of 0.76 was achieved using the medium-sized oligomer BIT6F with the optimized film morphology. This efficiency is the highest value reported for organic solar cells from small-molecules without rhodanine terminal group. More excitingly, devices from the shortest oligomer BIT4F showed an impressively high FF of 0.77 (the highest FF value reported for solution-processed small-molecule organic solar cells). These results indicate that photovoltaic performances of oligomers can be modulated through successive change in chain-length and fluorine atoms, alternating spatial symmetric core, and combined post-treatments. PMID:27225322

  10. Stratospheric water vapor feedback.

    Science.gov (United States)

    Dessler, A E; Schoeberl, M R; Wang, T; Davis, S M; Rosenlof, K H

    2013-11-01

    We show here that stratospheric water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that stratospheric water vapor increases with tropospheric temperature, implying the existence of a stratospheric water vapor feedback. We estimate the strength of this feedback in a chemistry-climate model to be +0.3 W/(m(2)⋅K), which would be a significant contributor to the overall climate sensitivity. One-third of this feedback comes from increases in water vapor entering the stratosphere through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause. PMID:24082126

  11. Bioeffects due to acoustic droplet vaporization

    Science.gov (United States)

    Bull, Joseph

    2015-11-01

    Encapsulated micro- and nano-droplets can be vaporized via ultrasound, a process termed acoustic droplet vaporization. Our interest is primarily motivated by a developmental gas embolotherapy technique for cancer treatment. In this methodology, infarction of tumors is induced by selectively formed vascular gas bubbles that arise from the acoustic vaporization of vascular microdroplets. Additionally, the microdroplets may be used as vehicles for localized drug delivery, with or without flow occlusion. In this talk, we examine the dynamics of acoustic droplet vaporization through experiments and theoretical/computational fluid mechanics models, and investigate the bioeffects of acoustic droplet vaporization on endothelial cells and in vivo. Early timescale vaporization events, including phase change, are directly visualized using ultra-high speed imaging, and the influence of acoustic parameters on droplet/bubble dynamics is discussed. Acoustic and fluid mechanics parameters affecting the severity of endothelial cell bioeffects are explored. These findings suggest parameter spaces for which bioeffects may be reduced or enhanced, depending on the objective of the therapy. This work was supported by NIH grant R01EB006476.

  12. Analytical investigation of the feasibility of sacrificial microchannel sealing for Chip-Scale Atomic Magnetometers

    OpenAIRE

    Tsujimoto, Kazuya; Hirai, Yoshikazu; Sugano, Koji; Tsuchiya, Toshiyuki; TABATA, Osamu

    2014-01-01

    An alkali metal vapor cell is a crucial component of the highly sensitive Chip Scale Atomic Magnetometers (CSAMs) that are increasingly deployed in a variety of electronic devices. Herein, we propose a novel microfabrication technique utilizing an array of microchannels at a bonded interface, to enable gas feedthrough for evacuation of unwanted gases from a vapor cell and subsequent introduction of an inert gas, followed by permanent sealing of the microchannels by reflow of a glass frit. The...

  13. Vapor pressures and enthalpies of vaporization of azides

    Energy Technology Data Exchange (ETDEWEB)

    Verevkin, Sergey P., E-mail: sergey.verevkin@uni-rostock.de [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Emel' yanenko, Vladimir N. [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Algarra, Manuel [Centro de Geologia do Porto, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Manuel Lopez-Romero, J. [Department of Organic Chemistry, University of Malaga. Campus de Teatinos s/n, 29071 Malaga (Spain); Aguiar, Fabio; Enrique Rodriguez-Borges, J.; Esteves da Silva, Joaquim C.G. [Centro de Investigacao em Quimica (CIQ-UP), Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2011-11-15

    Highlights: > We prepared and measured vapor pressures and vaporization enthalpies of 7 azides. > We examined consistency of new and available in the literature data. > Data for geminal azides and azido-alkanes selected for thermochemical calculations. - Abstract: Vapor pressures of some azides have been determined by the transpiration method. The molar enthalpies of vaporization {Delta}{sub l}{sup g}H{sub m} of these compounds were derived from the temperature dependencies of vapor pressures. The measured data sets were successfully checked for internal consistency by comparison with vaporization enthalpies of similarly structured compounds.

  14. Alkali metals in combustion of biomass with coal

    OpenAIRE

    Glazer, M.P.

    2007-01-01

    Growing demand for energy in the world, depletion of fossil fuels and green house effect require from us to utilize alternative, renewable sources of power. Biomass gained in the last few years more and more attention especially in Europe. Many research programs focused on the various forms of thermal biomass utilization have been launched and successfully accomplished expanding our knowledge and contributing to the, so-called, sustainable development. Utilization of straw, biomass present in...

  15. Near-threshold photodetachment of heavy alkali-metal anions

    International Nuclear Information System (INIS)

    We calculate near-threshold photodetachment cross sections for Rb-, Cs-, and Fr- using the Pauli equation method with a model potential describing the effective electron-atom interaction. Parameters of the model potential are fitted to reproduce ab initio scattering phase shifts obtained from Dirac R-matrix calculations. Special care is taken to formulate the boundary conditions near the atomic nucleus for solving the Pauli equation, based on the analytic solution of the Dirac equation for a Coulomb potential. We find a 3P1o resonance contribution to the photodetachment cross section of Rb-, Cs-, and Fr- ions. Our calculated total photodetachment cross sections for Cs agree with experiments after tuning the resonance position by 2.4 meV. For Rb- and Fr- the resonance contribution is much smaller than for Cs. We therefore also provide angle-differential cross sections and asymmetry parameters which are much more sensitive to the resonant contribution than total cross sections

  16. Nanoconfined Alkali-metal borohydrides for Reversible Hydrogen Storage

    NARCIS (Netherlands)

    Ngene, P.

    2012-01-01

    Hydrogen has been identified as a promising energy carrier. Its combustion is not associated with pollution when generated from renewable energy sources like solar and wind. The large-scale use of hydrogen for intermittent energy storage and as a fuel for cars can contribute to the realization of a

  17. Ultracold chemistry with alkali-metal-rare-earth molecules

    CERN Document Server

    Makrides, C; Pradhan, G B; Petrov, A; Kendrick, B K; González-Lezana, T; Balakrishnan, N; Kotochigova, S

    2014-01-01

    A first principles study of the dynamics of $^6$Li($^{2}$S) + $^6$Li$^{174}$Yb($^2\\Sigma^+$)$ \\to ^6$Li$_2(^1\\Sigma^+$) + $^{174}$Yb($^1$S) reaction is presented at cold and ultracold temperatures. The computations involve determination and analytic fitting of a three-dimensional potential energy surface for the Li$_2$Yb system and quantum dynamics calculations of varying complexities, ranging from exact quantum dynamics within the close-coupling scheme, to statistical quantum treatment, and universal models. It is demonstrated that the two simplified methods yield zero-temperature limiting reaction rate coefficients in reasonable agreement with the full close-coupling calculations. The effect of the three-body term in the interaction potential is explored by comparing quantum dynamics results from a pairwise potential that neglects the three-body term to that derived from the full interaction potential. Inclusion of the three-body term in the close-coupling calculations was found to reduce the limiting rate ...

  18. Alkali metals in combustion of biomass with coal

    NARCIS (Netherlands)

    Glazer, M.P.

    2007-01-01

    Growing demand for energy in the world, depletion of fossil fuels and green house effect require from us to utilize alternative, renewable sources of power. Biomass gained in the last few years more and more attention especially in Europe. Many research programs focused on the various forms of therm

  19. Alkali-metal/alkaline-earth-metal fluorine beryllium borate NaSr{sub 3}Be{sub 3}B{sub 3}O{sub 9}F{sub 4} with large nonlinear optical properties in the deep-ultraviolet region

    Energy Technology Data Exchange (ETDEWEB)

    Reshak, A. H., E-mail: maalidph@yahoo.com [New Technologies—Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Huang, Hongwei [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Kamarudin, H. [Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Auluck, S. [Council of Scientific and Industrial Research—National Physical Laboratory, Dr. K S Krishnan Marg, New Delhi 110012, India and Physics Department, Indian Institute of Technology - Delhi, Hauz Khas, New Delhi 110016 (India)

    2015-02-28

    The linear optical response and second harmonic generation (SHG) in alkali-metal/alkaline-earth-metal fluorine beryllium borate NaSr{sub 3}Be{sub 3}B{sub 3}O{sub 9}F{sub 4} are investigated by means of density functional theory. Calculations are performed using four types of exchange correlations: Ceperley-Alder local density approximation, Perdew Burke and Ernzerhof general gradient approximation, Engel-Vosko generalized gradient approximation, and the recently modified Becke-Johnson potential (mBJ). The mBJ approach brings the calculated band gap (7.20 eV) in excellent agreement with the experimental one (7.28 eV). The calculated values of the uniaxial anisotropy δε=−0.076 and the birefringence Δn(0)=0.052 indicate considerable anisotropy in the linear optical properties, which makes it favorable for the second harmonic generation. The dominant component of the second harmonic generation is χ{sub 111}{sup (2)}(ω). The value of |χ{sub 111}{sup (2)}(ω)| is about 1.2 pm/V at λ = 1064 nm in agreement with previous calculations. To analyze the origin of the high SHG of NaSr{sub 3}Be{sub 3}B{sub 3}O{sub 9}F{sub 4} single crystals, we have correlated the features of |χ{sub 111}{sup (2)}(ω)| spectra with the features of ε{sub 2}(ω) spectra as a function of ω/2 and ω. From the calculated dominant component |χ{sub 111}{sup (2)}(ω)|, we find that the microscopic first hyperpolarizability, β{sub 111}, the vector components along the dipole moment direction is 0.5 × 10{sup −30} esu at static limit and 0.6 × 10{sup −30} esu at λ = 1064 nm.

  20. Low-pressure, chemical vapor deposition polysilicon

    Science.gov (United States)

    Gallagher, B. D.; Crotty, G. C.

    1986-01-01

    The low-pressure chemical vapor deposition (LPCVD) of polycrystalline silicon was investigted. The physical system was described, as was the controlling process parameters and requirements for producing films for use as an integral portion of the solar cell contact system.

  1. Ternary alkali-metal and transition metal or metalloid acetylides as alkali-metal intercalation electrodes for batteries

    Energy Technology Data Exchange (ETDEWEB)

    Nemeth, Karoly; Srajer, George; Harkay, Katherine C; Terdik, Joseph Z

    2015-02-10

    Novel intercalation electrode materials including ternary acetylides of chemical formula: A.sub.nMC.sub.2 where A is alkali or alkaline-earth element; M is transition metal or metalloid element; C.sub.2 is reference to the acetylide ion; n is an integer that is 0, 1, 2, 3 or 4 when A is alkali element and 0, 1, or 2 when A is alkaline-earth element. The alkali elements are Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). The alkaline-earth elements are Berilium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). M is a transition metal that is any element in groups 3 through 12 inclusive on the Periodic Table of Elements (elements 21 (Sc) to element 30 (Zn)). In another exemplary embodiment, M is a metalloid element.

  2. Passive Vaporizing Heat Sink

    Science.gov (United States)

    Knowles, TImothy R.; Ashford, Victor A.; Carpenter, Michael G.; Bier, Thomas M.

    2011-01-01

    A passive vaporizing heat sink has been developed as a relatively lightweight, compact alternative to related prior heat sinks based, variously, on evaporation of sprayed liquids or on sublimation of solids. This heat sink is designed for short-term dissipation of a large amount of heat and was originally intended for use in regulating the temperature of spacecraft equipment during launch or re-entry. It could also be useful in a terrestrial setting in which there is a requirement for a lightweight, compact means of short-term cooling. This heat sink includes a hermetic package closed with a pressure-relief valve and containing an expendable and rechargeable coolant liquid (e.g., water) and a conductive carbon-fiber wick. The vapor of the liquid escapes when the temperature exceeds the boiling point corresponding to the vapor pressure determined by the setting of the pressure-relief valve. The great advantage of this heat sink over a melting-paraffin or similar phase-change heat sink of equal capacity is that by virtue of the =10x greater latent heat of vaporization, a coolant-liquid volume equal to =1/10 of the paraffin volume can suffice.

  3. Vapor liquid fraction determination

    International Nuclear Information System (INIS)

    This invention describes a method of measuring liquid and vapor fractions in a non-homogeneous fluid flowing through an elongate conduit, such as may be required with boiling water, non-boiling turbulent flows, fluidized bed experiments, water-gas mixing analysis, and nuclear plant cooling. (UK)

  4. Thermodynamics and Kinetics of Silicate Vaporization

    Science.gov (United States)

    Jacobson, Nathan S.; Costa, Gustavo C. C.

    2015-01-01

    Silicates are a common class of materials that are often exposed to high temperatures. The behavior of these materials needs to be understood for applications as high temperature coatings in material science as well as the constituents of lava for geological considerations. The vaporization behavior of these materials is an important aspect of their high temperature behavior and it also provides fundamental thermodynamic data. The application of Knudsen effusion mass spectrometry (KEMS) to silicates is discussed. There are several special considerations for silicates. The first is selection of an appropriate cell material, which is either nearly inert or has well-understood interactions with the silicate. The second consideration is proper measurement of the low vapor pressures. This can be circumvented by using a reducing agent to boost the vapor pressure without changing the solid composition or by working at very high temperatures. The third consideration deals with kinetic barriers to vaporization. The measurement of these barriers, as encompassed in a vaporization coefficient, is discussed. Current measured data of rare earth silicates for high temperature coating applications are discussed. In addition, data on magnesium-iron-silicates (olivine) are presented and discussed.

  5. Electrolytic systems and methods for making metal halides and refining metals

    Energy Technology Data Exchange (ETDEWEB)

    Holland, Justin M.; Cecala, David M.

    2015-05-26

    Disclosed are electrochemical cells and methods for producing a halide of a non-alkali metal and for electrorefining the halide. The systems typically involve an electrochemical cell having a cathode structure configured for dissolving a hydrogen halide that forms the halide into a molten salt of the halogen and an alkali metal. Typically a direct current voltage is applied across the cathode and an anode that is fabricated with the non-alkali metal such that the halide of the non-alkali metal is formed adjacent the anode. Electrorefining cells and methods involve applying a direct current voltage across the anode where the halide of the non-alkali metal is formed and the cathode where the non-alkali metal is electro-deposited. In a representative embodiment the halogen is chlorine, the alkali metal is lithium and the non-alkali metal is uranium.

  6. Crystal structures of new alkali metal-rich oxometallates. Rubidium aluminate tetrahydroxide, Rb{sub 9}(AlO{sub 4})(OH){sub 4}, rubidium orthogallate, Rb{sub 5}GaO{sub 4}, cesium bis-chromate(IV) oxide, Cs{sub 10}(CrO{sub 4}){sub 2}O, and cesium diindate, Cs{sub 8}In{sub 2}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Bender, Johannes; Wohlfarth, Andreas; Hoch, Constantin [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)

    2010-12-15

    Several new alkali metal oxometallates with anions built up from tetrahedral [MO{sub 4}] units were obtained in reactions aimed at the formation of alkali metal suboxometallates or by thermally decomposing the latter. Rubidium orthoaluminate tetrahydroxide Rb{sub 9}(AlO{sub 4})(OH){sub 4} crystallizes with a new structure type (space group P2{sub 1}/c, a = 13.116(1), b = 6.9266(5), c = 18.934(2) A, {beta} = 92.05(1) , V = 1719.0(3) A{sup 3}, Z = 4, R1 = 0.0352) and contains orthoaluminate anions [AlO{sub 4}]{sup 5-} and isolated hydroxide anions. Rubidium orthogallate Rb{sub 5}GaO{sub 4} crystallizes with the Na{sub 5}GaO{sub 4} structure type (space group Pbca, a = 6.9318(5), b = 21.309(2), c = 11.740(1) A, V = 1734.2(3) A{sup 3}, Z = 8, R1 = 0.0423) with isolated orthogallate anions [GaO{sub 4}]{sup 5-}. Cesium chromate oxide Cs{sub 10}(CrO{sub 4}){sub 2}O adopts the Cs{sub 10}(GeO{sub 4}){sub 2}O structure type (space group P2{sub 1}/c, a = 12.903(1), b = 11.4523(8), c = 19.074(3) A, {beta} = 127.903(8) , V = 2223.9(4) A{sup 3}, Z = 4, R1 = 0.0326) with orthochromate(IV) anions [CrO{sub 4}]{sup 4-} and isolated oxide anions. In all orthometallates the anions [MO{sub 4}]{sup n-} deviate only slightly from ideal tetrahedral symmetry. Cesium diindate Cs{sub 8}In{sub 2}O{sub 7} crystallizes with the Cs{sub 8}Fe{sub 2}O{sub 7} structure type (space group P2{sub 1}/c, a = 7.4307(6), b = 18.6181(14), c = 7.2639(6) A {beta} = 119.225(8) , V = 877.0(1) A{sup 3}, Z = 2, R1 = 0.0349). A single-crystal structure investigation at r.t. has shown linear diindate units, but the temperature dependence of the libration angles from TLS studies for the bridging oxygen atom suggests a slightly bent and dynamically disordered diindate anion. (orig.)

  7. Wide range and highly sensitive atomic magnetometry with Rb vapor

    CERN Document Server

    Iftiquar, S M

    2007-01-01

    We have developed a technique in which Rb atomic response to weak magnetic field is high and an efficient rotation of linearly polarized laser beam results in efficient magnetometry. 85Rb isotope has been used for the magnetometry in an ordinary vapor cell without any paraffin coating to its inner wall. A linear regime of Faraday rotation of about 25 microT has been observed with atomic number density within the vapor cell of about 10^9 cm-3.

  8. Mixed-Halide CH3 NH3 PbI3-x Xx (X=Cl, Br, I) Perovskites: Vapor-Assisted Solution Deposition and Application as Solar Cell Absorbers.

    Science.gov (United States)

    Sedighi, Rahime; Tajabadi, Fariba; Shahbazi, Saeed; Gholipour, Somayeh; Taghavinia, Nima

    2016-08-01

    There have been recent reports on the formation of single-halide perovskites, CH3 NH3 PbX3 (X=Cl, Br, I), by means of vapor-assisted solution processing. Herein, the successful formation of mixed-halide perovskites (CH3 NH3 PbI3-x Xx ) by means of a vapor-assisted solution method at ambient atmosphere is reported. The perovskite films are synthesized by exposing PbI2 film to CH3 NH3 X (X=I, Br, or Cl) vapor. The prepared perovskite films have uniform surfaces with good coverage, as confirmed by SEM images. The inclusion of chlorine and bromine into the structure leads to a lower temperature and shorter reaction time for optimum perovskite film formation. In the case of CH3 NH3 PbI3-x Clx , the optimum reaction temperature is reduced to 100 °C, and the resulting phases are CH3 NH3 PbI3 (with trace Cl) and CH3 NH3 PbCl3 with a ratio of about 2:1. In the case of CH3 NH3 PbI3-x Brx , single-phase CH3 NH3 PbI2 Br is formed in a considerably shorter reaction time than that of CH3 NH3 PbI3 . The mesostructured perovskite solar cells based on CH3 NH3 PbI3 films show the best optimal power conversion efficiency of 13.5 %, whereas for CH3 NH3 PbI3-x Clx and CH3 NH3 PbI3-x Brx the best recorded efficiencies are 11.6 and 10.5 %, respectively.

  9. Vapor CdCl2—optimization and screening experiments for an all dry chloride treatment of CdS/CdTe solar cells

    Science.gov (United States)

    Mahathongdy, Yoxa; Albin, David S.; Wolden, Colin A.; Baldwin, Robert M.

    1999-03-01

    A dry vapor treatment of CdCl2 is being developed as an alternative approach to the conventional solution CdCl2 treatment of CdS/CdTe devices. In this alternative process, the CdS/CdTe substrates are vapor treated in a close-spaced sublimation configuration. A 16-run Plackett-Burman screening experiment identified source temperature, substrate temperature, and treatment time as being the most significant parameters in the process. Subsequently, a 20-run Central Composite Design showed that a source temperature of 380-390 °C, a temperature gradient (ΔT) of 5 °C, and a time of 10 minutes provides the most process tolerant combination, yielding a total-area efficiency of 12.6%. A strong interaction between ΔT and treatment time was also identified. The model indicated that for a small ΔT, device performance improved with decreasing time, whereas at larger values of ΔT, performance increased with increasing time.

  10. VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

    Energy Technology Data Exchange (ETDEWEB)

    Eric M. Suuberg; Vahur Oja

    1997-07-01

    This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization which have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.

  11. New alkali metal diphosphates how materials to preserve the security of the environment: CsNaCu(P2O7), Rb2Cu(P2O7) and CsNaCo(P2O7) synthesis and crystal structure determination

    Science.gov (United States)

    Chernyatieva, Anastasiya; Filatova, Alyona; Spiridonova, Dariya; Krivovichev, Sergey

    2013-04-01

    In this work we describe preliminary results of the synthesis and of a crystal-chemical study of synthetic phosphates with transition metals. Due to the increasing requirements for environmental safety specialists from various industries, we are searching for sustainable forms of immobilization of hazardous waste during storage. We are also developing a component-based waste for new materials. In our continued exploratory synthesis of compounds containing transition-metals, we were able to produce the new diphosphate phases CsNaCu(P2O7), Rb2Cu(P2O7) and CsNaCo(P2O7). A crystal chemical study has allowed us to identify new phosphates. Crystals of CsNaCu(P2O7) (Phase 1) is orthorhombic, crystallizes in space group Pmn21, with a = 5.147(8), b = 15.126(2), c = 9.717(2) Å, V = 756.20 Å3, R1 = 0.066 and Rb2Cu(P2O7) (Phase 2) is orthorhombic as well, crystallizes in space group Pmcn, with a = 5.183(8), b = 10.096(1), c = 15.146(3) Å, V = 793.55 Å3, R1 = 0.063, they have been obtained by high-temperature reaction of RbNO3, CsNO3, Cu(NO3)2, NaOH and (NH4)4P2O7. Synthetic crystals of the phosphate of copper and rubidium were studied in detail by us on the structures of Rb2Cu(P2O7) and Rb2Cu3(P2O7)2 - new alkali metal copper diphosphates (CHERNYATIEVA et al., 2008). Here we report the synthesis, the structure and the properties of the title compounds and we compare these phases with the previously discovered K2CuP2O7 (ELMAADI et al., 1995) and CsNaMnP2O7 (HUANG et al., 1998). These structures crystallize in other space groups, although their structures are also based on 2-D layers, formed by P2O7 groups combined with polyhedra of the transition metals (CHERNYATIEVA et al., 2012). A crystal chemical study has allowed us to identify even new diphosphates CsNaCu(P2O7) (Phase 3). Crystals of CsNaCoP2O7 is monoclinic, space group P 21/n, with a = 7,424(2), b = 7,648(1), c = 12,931(3)Å, β = 90,71(2)° , V = 734.2(3) Å3 and R1 = 0.060. The structure is based framework of Co

  12. Electrical properties of carbon nanotubes in flowing vapor

    Institute of Scientific and Technical Information of China (English)

    XIAO Peng; WANG Xin-qiang; ZHANG Yun-huai

    2006-01-01

    Electric potentials were generated from carbon nanotubes immersed in flowing vapors.The nanomaterials used in this study were multiwall carbon nanotubes(MWCNTs) and silver nanopowders.These nanomaterials were dispersed and densely packed on a substrate and immersed in flowing vapors generated from solution such as water,ethanol and KCl.The potentials generated from these samples were measured by a voltmeter.Experimental results showed that the electric potentials were produced at the surface of the MWCNT samlpes,and strongly dependent on the pretreatment of MWCNT and properties of the flowing vapors.The mechanism of vapor-flow induced potentials may be ascribed to ions in the flowing vapors.This property of MWCNTs can advantage their application to nanoscale sensors,detectors and power cells.

  13. High-resolution Resonance Bragg-scattering spectroscopy of an atomic transition from a population difference grating in a vapor cell

    CERN Document Server

    Wang*, Hai; Li, Shujing; Zhang, Chunhong; Xie, Changde; Peng, Kunchi

    2009-01-01

    The laser spectroscopy with a narrow linewidth and high signal to noise ratio (S/N) is very important in the precise measurement of optical frequencies. Here, we present a novel high-resolution backward resonance Bragg-scattering (RBS) spectroscopy from a population difference grating (PDG). The PDG is formed by a standing-wave (SW) pump field in thermal 87Rb vapor, which periodically modulates the space population distribution of two levels in the 87Rb D1 line. A probe beam, having the identical frequency and the orthogonal polarization with the SW pump field, is Bragg-scattered by the PDG. Such Bragg-scattered light becomes stronger at an atomic resonance transition, which forms the RBS spectrum with a high S/N and sub-natural linewidth. Using the scheme of the coherent superposition of the individual Rayleigh-scattered light emitted from the atomic dipole oscillators on the PDG, the experimentally observed RBS spectroscopy is theoretically explained.

  14. Ca-Rich Carbonate Melts: A Regular-Solution Model, with Applications to Carbonatite Magma + Vapor Equilibria and Carbonate Lavas on Venus

    Science.gov (United States)

    Treiman, Allan H.

    1995-01-01

    A thermochemical model of the activities of species in carbonate-rich melts would be useful in quantifying chemical equilibria between carbonatite magmas and vapors and in extrapolating liquidus equilibria to unexplored PTX. A regular-solution model of Ca-rich carbonate melts is developed here, using the fact that they are ionic liquids, and can be treated (to a first approximation) as interpenetrating regular solutions of cations and of anions. Thermochemical data on systems of alkali metal cations with carbonate and other anions are drawn from the literature; data on systems with alkaline earth (and other) cations and carbonate (and other) anions are derived here from liquidus phase equilibria. The model is validated in that all available data (at 1 kbar) are consistent with single values for the melting temperature and heat of fusion for calcite, and all liquidi are consistent with the liquids acting as regular solutions. At 1 kbar, the metastable congruent melting temperature of calcite (CaCO3) is inferred to be 1596 K, with (Delta)bar-H(sub fus)(calcite) = 31.5 +/- 1 kJ/mol. Regular solution interaction parameters (W) for Ca(2+) and alkali metal cations are in the range -3 to -12 kJ/sq mol; W for Ca(2+)-Ba(2+) is approximately -11 kJ/sq mol; W for Ca(2+)-Mg(2+) is approximately -40 kJ/sq mol, and W for Ca(2+)-La(3+) is approximately +85 kJ/sq mol. Solutions of carbonate and most anions (including OH(-), F(-), and SO4(2-)) are nearly ideal, with W between 0(ideal) and -2.5 kJ/sq mol. The interaction of carbonate and phosphate ions is strongly nonideal, which is consistent with the suggestion of carbonate-phosphate liquid immiscibility. Interaction of carbonate and sulfide ions is also nonideal and suggestive of carbonate-sulfide liquid immiscibility. Solution of H2O, for all but the most H2O-rich compositions, can be modeled as a disproportionation to hydronium (H3O(+)) and hydroxyl (OH(-)) ions with W for Ca(2+)-H3O(+) (approximately) equals 33 kJ/sq mol. The

  15. Stability of Materials in High Temperature Water Vapor: SOFC Applications

    Science.gov (United States)

    Opila, E. J.; Jacobson, N. S.

    2010-01-01

    Solid oxide fuel cell material systems require long term stability in environments containing high-temperature water vapor. Many materials in fuel cell systems react with high-temperature water vapor to form volatile hydroxides which can degrade cell performance. In this paper, experimental methods to characterize these volatility reactions including the transpiration technique, thermogravimetric analysis, and high pressure mass spectrometry are reviewed. Experimentally determined data for chromia, silica, and alumina volatility are presented. In addition, data from the literature for the stability of other materials important in fuel cell systems are reviewed. Finally, methods for predicting material recession due to volatilization reactions are described.

  16. Study of vaporization of LiI, LiI/C70, LiI/LiF/C70 from the Knudsen cell located into ionization chamber of the mass spectrometer

    Directory of Open Access Journals (Sweden)

    Đustebek Jasmina

    2014-01-01

    Full Text Available The vaporization of LiI, LiI/C70 and LiI/LIF/C70 were studied using a Knudsen cell located into ionization chamber of a magnetic sector mass spectrometer in a temperature range from 350 ˚C to 850 ˚C. Аs the ion species, LinI+ (n = 2, 3, 4, and 6 were identified from a mixture LiI/C70. While the clusters LinI+ and LinF+ (n = 2 - 6 were detected from a mixture LiI/LiF/C70. The intensities of LinI+ were higher than the emission of LinF+ cluster when the ratio of LiI to LiF was 2:1. By contrast, the emission of the LinF+ is favored when the ratio of LiI to LiF was 1:2. These results show that the vaporization of a mixture LiI/LIF/C70 from the Knudsen cell located into ionization chamber of the mass spectrometer represents an efficient and simple way to obtain and investigate clusters of the type LinX, X-F, I. In this work it has also been shown that the trend of the ln (Intensity, arbit. units versus temperature for all LinI+ clusters before and after the melting point of LiI was not same. It suggested that the way of the formation of these clusters can be different due to changes in temperature. [Projekat Ministarstva nauke Republike Srbije, br. 172019

  17. Performance improvement of inverted organic solar cells by adding ultrathin Al2O3 as an electron selective layer and a plasma enhanced chemical vapor deposition of SiOx encapsulating layer

    International Nuclear Information System (INIS)

    In this paper, we report the performance improvement of inverted organic solar cells by adding an ultrathin electron selective layer of Al2O3 prepared between the indium tin oxide (ITO) electrode and the active transport layer through atomic layer deposition (ALD). We evaluated the cell shelf-life after encapsulating with SiOx-coated polyethylene terephthalate, where the SiOx layer was made by plasma enhanced chemical vapor deposition (PECVD). It was found that the devices with ALD Al2O3 have a higher open circuit voltage than those without the ALD Al2O3 layer. Al2O3 deposited on an ITO electrode decreased the work function of ITO. Furthermore, based on the current density–voltage curves of the initial devices showing a pronounced S-shape, we soaked the cells with the ultraviolet (UV) light process. Then we obtained a higher efficiency in these ALD Al2O3 treated devices. With a careful analysis by atomic force microscopic and X-ray photoelectron spectroscopy, we believe that the UV light soaking process affected both ITO and Al2O3. Further, after the encapsulation by PECVD SiOx, our devices achieved a shelf-life of over 500 h for 50% retained cell efficiency. - Highlights: • Atomic layer deposition of Al2O3 improved the property of inverted organic solar cells. • Ultraviolet light soaking affected electrode work function and Al2O3 conductivity. • SiOx coating enveloped cells can achieve a 500 h shelf-life

  18. Iron bromide vapor laser

    Science.gov (United States)

    Sukhanov, V. B.; Shiyanov, D. V.; Trigub, M. V.; Dimaki, V. A.; Evtushenko, G. S.

    2016-03-01

    We have studied the characteristics of a pulsed gas-discharge laser on iron bromide vapor generating radiation with a wavelength of 452.9 nm at a pulse repetition frequency (PRF) of 5-30 kHz. The maximum output power amounted to 10 mW at a PRF within 5-15 kHz for a voltage of 20-25 kV applied to electrodes of the discharge tube. Addition of HBr to the medium produced leveling of the radial profile of emission. Initial weak lasing at a wavelength of 868.9 nm was observed for the first time, which ceased with buildup of the main 452.9-nm line.

  19. Water vapor: An extraordinary terahertz wave source under optical excitation

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Keith [Massachusetts Institute of Technology, PO Box 380792, Cambridge, MA 02238-0792 (United States); HydroElectron Ventures Inc., 1303 Greene Avenue Suite 102, Westmount, QC, H3Z 2A7 (Canada)], E-mail: kjohnson@mit.edu; Price-Gallagher, Matthew [HydroElectron Ventures Inc., 1303 Greene Avenue Suite 102, Westmount, QC, H3Z 2A7 (Canada); Mamer, Orval; Lesimple, Alain [Mass Spectroscopy Unit, 740 Dr. Penfield, Suite 5300, McGill University, Montreal, QC, H3A 1A4 (Canada); Fletcher, Clark [HydroElectron Ventures Inc., 1303 Greene Avenue Suite 102, Westmount, QC, H3Z 2A7 (Canada); Chen Yunqing; Lu Xiaofei; Yamaguchi, Masashi; Zhang, X.-C. [W.M. Keck Laboratory for Terahertz Science, Center for Terahertz Research, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    2008-09-15

    In modern terahertz (THz) sensing and imaging spectroscopy, water is considered a nemesis to be avoided due to strong absorption in the THz frequency range. Here we report the first experimental demonstration and theoretical implications of using femtosecond laser pulses to generate intense broadband THz emission from water vapor. When we focused an intense laser pulse in water vapor contained in a gas cell or injected from a gas jet nozzle, an extraordinarily strong THz field from optically excited water vapor is observed. Water vapor has more than 50% greater THz generation efficiency than dry nitrogen. It had previously been assumed that the nonlinear generation of THz waves in this manner primarily involves a free-electron plasma, but we show that the molecular structure plays an essential role in the process. In particular, we found that THz wave generation from H{sub 2}O vapor is significantly stronger than that from D{sub 2}O vapor. Vibronic activities of water cluster ions, occurring naturally in water vapor, may possibly contribute to the observed isotope effect along with rovibrational contributions from the predominant monomers.

  20. Water Vapor: An Extraordinary Terahertz Wave Source under Optical Excitation

    CERN Document Server

    Johnson, Keith; Mamer, Orval; Lesimple, Alain; Fletcher, Clark; Chen, Yunqing; Lu, Xiaofei; Yamaguchi, Masashi; Zhang, X -C; 10.1016/j.physleta.2008.07.071

    2009-01-01

    In modern terahertz (THz) sensing and imaging spectroscopy, water is considered a nemesis to be avoided due to strong absorption in the THz frequency range. Here we report the first experimental demonstration and theoretical implications of using femtosecond laser pulses to generate intense broadband THz emission from water vapor. When we focused an intense laser pulse in water vapor contained in a gas cell or injected from a gas jet nozzle, an extraordinarily strong THz field from optically excited water vapor is observed. Water vapor has more than 50% greater THz generation efficiency than dry nitrogen. It had previously been assumed that the nonlinear generation of THz waves in this manner primarily involves a free-electron plasma, but we show that the molecular structure plays an essential role in the process. In particular, we found that THz wave generation from H2O vapor is significantly stronger than that from D2O vapor. Vibronic activities of water cluster ions, occurring naturally in water vapor, may...

  1. Vapor Pressure, Vapor Composition and Fractional Vaporization of High Temperature Lavas on Io

    Science.gov (United States)

    Fegley, B., Jr.; Schaefer, L.; Kargel, J. S.

    2003-01-01

    Observations show that Io's atmosphere is dominated by SO2 and other sulfur and sulfur oxide species, with minor amounts of Na, K, and Cl gases. Theoretical modeling and recent observations show that NaCl, which is produced volcanically, is a constituent of the atmosphere. Recent Galileo, HST and ground-based observations show that some volcanic hot spots on Io have extremely high temperatures, in the range 1400-1900 K. At similar temperatures in laboratory experiments, molten silicates and oxides have significant vapor pressures of Na, K, SiO, Fe, Mg, and other gases. Thus vaporization of these species from high temperature lavas on Io seems likely. We therefore modeled the vaporization of silicate and oxide lavas suggested for Io. Our results for vapor chemistry are reported here. The effects of fractional vaporization on lava chemistry are given in a companion abstract by Kargel et al.

  2. In situ chemical vapor deposition growth of carbon nanotubes on hollow CoFe2O4 as an efficient and low cost counter electrode for dye-sensitized solar cells

    Science.gov (United States)

    Yuan, Hong; Jiao, Qingze; Zhang, Shenli; Zhao, Yun; Wu, Qin; Li, Hansheng

    2016-09-01

    The composites of hollow CoFe2O4 and carbon nanotubes (h-CoFe2O4@CNTs) are successfully prepared by using a simple hydrothermal process coupling with the in-situ chemical vapor deposition (CVD) as electrocatalytic materials for counter electrode of dye-sensitized solar cells. The CNTs are uniformly grown on the surface of hollow CoFe2O4 particles verified by X-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) measurements. The electrochemical performances of hollow CoFe2O4@CNTs composites are evaluated by the EIS, Tafel polarization and CV measurements, and exhibiting high electrocatalytic performance for the reduction of triiodide. The presence of conductive polypyrrole nanoparticles could further improve the conductivity and catalytic performance of the resultant composites. Controlling the thickness of composites film, the optimum photovoltaic conversion efficiency of 6.55% is obtained, which is comparable to that of the cells fabricated with Pt counter electrode (6.61%). In addition, the composites exhibit a good long-term electrochemical stability in I3-/I- electrolyte.

  3. Passive vapor extraction feasibility study

    International Nuclear Information System (INIS)

    Demonstration of a passive vapor extraction remediation system is planned for sites in the 200 West Area used in the past for the disposal of waste liquids containing carbon tetrachloride. The passive vapor extraction units will consist of a 4-in.-diameter pipe, a check valve, a canister filled with granular activated carbon, and a wind turbine. The check valve will prevent inflow of air that otherwise would dilute the soil gas and make its subsequent extraction less efficient. The granular activated carbon is used to adsorb the carbon tetrachloride from the air. The wind turbine enhances extraction rates on windy days. Passive vapor extraction units will be designed and operated to meet all applicable or relevant and appropriate requirements. Based on a cost analysis, passive vapor extraction was found to be a cost-effective method for remediation of soils containing lower concentrations of volatile contaminants. Passive vapor extraction used on wells that average 10-stdft3/min air flow rates was found to be more cost effective than active vapor extraction for concentrations below 500 parts per million by volume (ppm) of carbon tetrachloride. For wells that average 5-stdft3/min air flow rates, passive vapor extraction is more cost effective below 100 ppm

  4. An exposure system for measuring nasal and lung uptake of vapors in rats

    Energy Technology Data Exchange (ETDEWEB)

    Dahl, A.R.; Brookins, L.K.; Gerde, P. [National Inst. for Working Life, Solna (Sweden)

    1995-12-01

    Inhaled gases and vapors often produce biological damage in the nasal cavity and lower respiratory tract. The specific site within the respirator tract at which a gas or vapor is absorbed strongly influences the tissues at risk to potential toxic effects; to predict or to explain tissue or cell specific toxicity of inhaled gases or vapors, the sites at which they are absorbed must be known. The purpose of the work reported here was to develop a system for determining nose and lung absorption of vapors in rats, an animal commonly used in inhalation toxicity studies. In summary, the exposure system described allows us to measure in the rate: (1) nasal absorption and desorption of vapors; (2) net lung uptake of vapors; and (3) the effects of changed breathing parameters on vapor uptake.

  5. Water Vapor-Mediated Volatilization of High-Temperature Materials

    Science.gov (United States)

    Meschter, Peter J.; Opila, Elizabeth J.; Jacobson, Nathan S.

    2013-07-01

    Volatilization in water vapor-containing atmospheres is an important and often unexpected mechanism of degradation of high-temperature materials during processing and in service. Thermodynamic properties data sets for key (oxy)hydroxide vapor product species that are responsible for material transport and damage are often uncertain or unavailable. Estimation, quantum chemistry calculation, and measurement methods for thermodynamic properties of these species are reviewed, and data judged to be reliable are tabulated and referenced. Applications of water vapor-mediated volatilization include component and coating recession in turbine engines, oxidation/volatilization of ferritic steels in steam boilers, chromium poisoning in solid-oxide fuel cells, vanadium transport in hot corrosion and degradation of hydrocracking catalysts, Na loss from Na β"-Al2O3 tubes, and environmental release of radioactive isotopes in a nuclear reactor accident or waste incineration. The significance of water vapor-mediated volatilization in these applications is described.

  6. Archimedes Mass Filter Vaporizer

    Science.gov (United States)

    Putvinski, S.; Agnew, A. F.; Cluggish, B. P.; Ohkawa, T.; Sevier, L.; Umstadter, K. R.; Dresvin, S. V.; Kuteev, B. V.; Feygenson, O. N.; Ivanov, D. V.; Zverev, S. G.; Miroshnikov, I. V.; Egorov, S. M.; Kiesewetter, D. V.; Maliugin, V. I.

    2001-10-01

    Archimedes Technology Group, Inc., is developing a plasma mass separator called the Archimedes Filter that separates waste oxide mixtures ion by ion into two mass groups: light and heavy. Since high-level waste at Hanford has 99.9its radioactivity associated with heavy elements, the Archimedes Filter can effectively decontaminate over three-quarters of that waste. The Filter process involves some preprocessing followed by volatilization and separation by the magnetic and electric fields of the main plasma. This presentation describes the approach to volatilization of the waste oxy-hydroxide mixture by means of a very high heat flux (q > 10 MW/m2). Such a high heat flux is required to ensure congruent evaporation of the complex oxy-hydroxide mixture and is achieved by injection of small droplets of molten waste into an inductively coupled plasma (ICP) torch. This presentation further addresses different issues related to evaporation of the waste including modeling of droplet evaporation, estimates of parameters of plasma torch, and 2D modeling of the plasma. The experimental test bed for oxide vaporization and results of the initial experiments on oxide evaporation in 60 kW ICP torch will also be described.

  7. Precision ozone vapor pressure measurements

    Science.gov (United States)

    Hanson, D.; Mauersberger, K.

    1985-01-01

    The vapor pressure above liquid ozone has been measured with a high accuracy over a temperature range of 85 to 95 K. At the boiling point of liquid argon (87.3 K) an ozone vapor pressure of 0.0403 Torr was obtained with an accuracy of + or - 0.7 percent. A least square fit of the data provided the Clausius-Clapeyron equation for liquid ozone; a latent heat of 82.7 cal/g was calculated. High-precision vapor pressure data are expected to aid research in atmospheric ozone measurements and in many laboratory ozone studies such as measurements of cross sections and reaction rates.

  8. VAPOR SHIELD FOR INDUCTION FURNACE

    Science.gov (United States)

    Reese, S.L.; Samoriga, S.A.

    1958-03-11

    This patent relates to a water-cooled vapor shield for an inductlon furnace that will condense metallic vapors arising from the crucible and thus prevent their condensation on or near the induction coils, thereby eliminating possible corrosion or shorting out of the coils. This is accomplished by placing, about the top, of the crucible a disk, apron, and cooling jacket that separates the area of the coils from the interior of the cruclbIe and provides a cooled surface upon whlch the vapors may condense.

  9. Design, Analyses, and Fabrication Procedure of Amtec Cell, Test Assembly, and Radioisotope Power System for Outer-Planet Missions

    Science.gov (United States)

    Schock, A.; Noravian, H.; Or, C.; Kumar, V.

    2002-04-01

    This paper describes the results of OSC's department of energy (DOE)-sponsored alkali metal thermal-to-electric conversion (AMTEC) generator studies. The paper was prepared in response to an invitation from the International Astronautic Federation for the presentation of a 1-h keynote lecture on our AMTEC studies at the Space Nuclear Power and Propulsion Systems session of the 48th International Astronautical Congress. The paper covers a broad range of topics, which explains its unusual length. After presenting the background of those studies and the operational principles of the AMTEC converters, it describes a novel methodology for the coupled solution of the interdependent thermal, electrical, and fluid flow differential and integral equations governing their performance, and the application of that procedure to OSC's recommended cell design. As explained in the paper, that design was the result of parametric analyses of 35 cell design variations to determine the individual effects of 27 design parameters and various operating parameters on the cell's power output, efficiency, and critical temperatures. The analysis revealed a method of substantially improving the cell's performance by enhancing the internal reflectivity of the cell wall, and identified a specific cell wall composition and coating to achieve that goal. The paper presents a set of OSC-recommended cell design parameters for the ultimate long-service flight generators, as well as a set of parameters for an interim cell design for planned short-term ground tests. The primary difference between them is that the ultimate design employs refractory metal components to enhance compatibility with high-temperature sodium vapor, while the interim design is based on stainless steel, nickel, and Haynes-25, which are expected to be adequate for initial short-term tests, but not for long-duration missions at high operating temperatures. The paper also presents a detailed fabrication sequence for the recommended

  10. High temperature vapor pressure of pure plutonium

    International Nuclear Information System (INIS)

    High temperature vapor pressure measurements have been made on pure plutonium metal by the Knudsen effusion technique. The reported experimental results extend into the transition region between molecular and viscous or hydrodynamic flow. Under the conditions used, linearity was observed up to temperatures in excess of 2200 K where pressures approaching 100 Pa were measured. The results over the temperature range 1724--2219 K yield log10P/sub Pu/(Pa) = (9.735 +- 0.105) -17066 +- 208/T and the enthalpy and entropy of vaporization and the standard deviations therein are ΔH0/sub v/(Pu,1975 K) =326.78 +- 3.97 kJ mol-1, ΔS0/sub v/(Pu,1975 K) =90.54 +- 2.01 J K-1 mol-1. Based on the most recently available free energy functions for plutonium liquid and gas, the values of the standard enthalpy of vaporization calculated via second- and third-law methods are ΔH0/sub v/(II, Pu,298 K) =344.14 +- 3.97 kJ mol-1, ΔH0/sub v/(III, Pu,298 K) =341.67 +- 1.26 kJ mol-1. Single crystal tungsten containers were used to hold the charge of plutonium and proved to be very satisfactory in alleviating problems of liquid metal creep and liquid/cell interactions normally encountered with actinides held at high temperatures for long periods

  11. A stratospheric water vapor feedback

    Science.gov (United States)

    Dessler, A. E.; Schoeberl, M. R.; Wang, T.; Davis, S. M.; Rosenlof, K. H.

    2013-12-01

    Variations in stratospheric water vapor play a role in the evolution of our climate. We show here that variations in water vapor since 2004 can be traced to tropical tropopause layer (TTL) temperature perturbations from at least three processes: the quasi-biennial oscillation, the strength of the Brewer-Dobson circulation, and the temperature of the troposphere. The connection between stratospheric water vapor and the temperature of the troposphere implies the existence of a stratospheric water vapor feedback. We estimate the feedback in a chemistry-climate model to have a magnitude of +0.3 W/m2/K, which could be a significant contributor to the overall climate sensitivity. About two-thirds of the feedback comes from the extratropical stratosphere below ~16 km (the lowermost stratosphere), with the rest coming from the stratosphere above ~16 km (the overworld).

  12. Tubing For Sampling Hydrazine Vapor

    Science.gov (United States)

    Travis, Josh; Taffe, Patricia S.; Rose-Pehrsson, Susan L.; Wyatt, Jeffrey R.

    1993-01-01

    Report evaluates flexible tubing used for transporting such hypergolic vapors as those of hydrazines for quantitative analysis. Describes experiments in which variety of tubing materials, chosen for their known compatibility with hydrazine, flexibility, and resistance to heat.

  13. Vapor deposition of hardened niobium

    Science.gov (United States)

    Blocher, Jr., John M.; Veigel, Neil D.; Landrigan, Richard B.

    1983-04-19

    A method of coating ceramic nuclear fuel particles containing a major amount of an actinide ceramic in which the particles are placed in a fluidized bed maintained at ca. 800.degree. to ca. 900.degree. C., and niobium pentachloride vapor and carbon tetrachloride vapor are led into the bed, whereby niobium metal is deposited on the particles and carbon is deposited interstitially within the niobium. Coating apparatus used in the method is also disclosed.

  14. Effects of Mo surface oxidation on Cu(In,Ga)Se2 solar cells fabricated by three-stage process with KF postdeposition treatment

    Science.gov (United States)

    Kamikawa, Yukiko; Nishinaga, Jiro; Ishizuka, Shogo; Shibata, Hajime; Niki, Shigeru

    2016-02-01

    The surface oxidation condition of the Mo back contact on a soda lime glass (SLG) substrate was varied by air annealing and chemical etching. Then, the evolution of a photovoltaic property was studied for Cu(In,Ga)Se2 (CIGS) solar cells grown by a three stage process with KF postdeposition treatment. Upon the removal of the oxidized layer from the Mo surface by chemical etching, the c-axis orientation of MoSe2 tended to be random, whereas the c-axis was perpendicular when the Mo surface was oxidized. An enhancement of the diffusion of Na and K from SLG to CIGS was observed upon removing the molybdenum oxide, which functions as a barrier to alkali-metal diffusion. The varied orientation of MoSe2 can also affect the alkali-metal diffusion kinetics. The open-circuit voltage (VOC) markedly increased after removing the oxidized layer from the Mo surface, mainly as a result of an increase in carrier density in CIGS.

  15. Realisation and characterization of organic photovoltaic cells obtained by physical vapor deposition; Realisation et caracterisation de cellules photovoltaiques organiques obtenues par depot physique

    Energy Technology Data Exchange (ETDEWEB)

    Brousse, B.

    2004-12-01

    This work deals with the synthesis and the characterization of low cost organic solar cells, contributing to the development of renewable energies, and able to feed devices as portable telephone...In particular, we have contributed to the development of an experimentation bench for the obtention of different structures (bilayers, interpenetrated and multilayers) of solar cells from different donor-acceptor couples of small molecules. After having presented a retrospective of the physical phenomena and of the mechanisms involved, as well as those of the photovoltaic principle in the organic materials, we describe the technological steps allowing to carry out the solar cells. The materials (organic and metallic) are deposited on thin films (of 30 to 100 nm) spin-coating (PEDOT-PSS) or by vacuum evaporation (small molecules and metallization of the cathode) on a glass substrate covered by a conducting and a semi-transparent ITO layer constituting the anode. The structures carried out have been characterized in air in obscurity and under illumination by curves I(V), by capacitive measurements and IPCE spectra (photocurrent spectra). Different donor-acceptor couples (phthalocyanine/C60, oligomer of thiophene/C60 and phthalocyanine/perylene derivative) have been tested by various configurations: p-n heterojunctions distributed or not in the volume. The obtained results are better for the bilayers structures on account of the granularity of the C60. This characteristics have allowed us to carry out an efficient multilayer structure (CuPc/C60). In order to resolve the problem of the deposit of the C60, we have tested another acceptor molecule: a derived compound of the perylene (PPTC). Complementary studies have been carried out by the ionic implantation of the active layers, allowing both a densification and a doping of these ones; the encapsulation of the compounds by polyimide VDP (gaseous phase polymerization) have been evaluated. With this technique, we have developed

  16. Dispensing fuel with aspiration of condensed vapors

    Energy Technology Data Exchange (ETDEWEB)

    Butkovich, M.S.; Strock, D.J.

    1993-08-10

    A vapor recovery process is described, comprising the steps of: fueling a motor vehicle with gasoline by discharging gasoline into a fill opening or filler pipe of a tank of said vehicle through a fuel outlet conduit of a nozzle; emitting gasoline vapors from said tank during said fueling; substantially collecting said vapors during said fueling with a vapor return conduit of said nozzle and passing said vapors through said vapor return conduit in counter current flow relationship to said discharging gasoline in said fuel conduit; conveying said vapors from said vapor return conduit to a vapor return hose; at least some of said vapors condensing to form condensate in said vapor return hose; substantially removing said condensate from said vapor return hose during said fueling with a condensate pickup tube from said nozzle by passing said condensate through said condensate pickup tube in counter current flow relationship to said conveying vapors in said vapor return hose; sensing the presence of gasoline with a liquid sensing tube in said vapor return conduit of said nozzle between inner and outer spouts of said nozzle to detect when said tank of said vehicle is filled with said fuel conduit being within the inner spout of said nozzle; and automatically shutting off said fueling and condensate removing when said liquid sensing tube detects when said tank of said vehicle is filled and fuel enters said vapor return conduit.

  17. Focusing Light Beams To Improve Atomic-Vapor Optical Buffers

    Science.gov (United States)

    Strekalov, Dmitry; Matsko, Andrey; Savchenkov, Anatoliy

    2010-01-01

    Specially designed focusing of light beams has been proposed as a means of improving the performances of optical buffers based on cells containing hot atomic vapors (e.g., rubidium vapor). There is also a companion proposal to improve performance by use of incoherent optical pumping under suitable conditions. Regarding the proposal to use focusing: The utility of atomic-vapor optical buffers as optical storage and processing devices has been severely limited by nonuniform spatial distributions of intensity in optical beams, arising from absorption of the beams as they propagate in atomic-vapor cells. Such nonuniformity makes it impossible to optimize the physical conditions throughout a cell, thereby making it impossible to optimize the performance of the cell as an optical buffer. In practical terms simplified for the sake of brevity, "to optimize" as used here means to design the cell so as to maximize the group delay of an optical pulse while keeping the absorption and distortion of the pulse reasonably small. Regarding the proposal to use incoherent optical pumping: For reasons too complex to describe here, residual absorption of light is one of the main impediments to achievement of desirably long group delays in hot atomic vapors. The present proposal is directed toward suppressing residual absorption of light. The idea of improving the performance of slow-light optical buffers by use of incoherent pumping overlaps somewhat with the basic idea of Raman-based slow-light systems. However, prior studies of those systems did not quantitatively answer the question of whether the performance of an atomic vapor or other medium that exhibits electromagnetically induced transparency (EIT) with Raman gain is superior to that of a medium that exhibits EIT without Raman gain.

  18. THE STABILITY OF VAPOR CONDENSATION EQUILIBRIUM

    OpenAIRE

    SHIMIN ZHANG

    2005-01-01

    The system must get across an energy peak of unstable equilibrium during the condensation of pure vapor; as the supersaturated extent of vapor increases and the temperature decreases, the energy peak shortens and vapor condensation becomes easier. The system must get across an energy peak of unstable equilibrium first, and then get into an energy valley of stable equilibrium during the condensation of impure vapor; as the partial pressure of vapor decreases, the energy peak becomes taller, th...

  19. Stage 2 vapor recovery system

    Energy Technology Data Exchange (ETDEWEB)

    Koch, W.H.; Strock, D.J.; Butkovich, M.S.; Hartman, H.B.

    1993-05-25

    A vapor recovery system is described, comprising: a set of elongated underground storage tanks, each storage tank containing a different grade of gasoline; vent pipes; a series of dispensing units; fuel flow lines; vapor return lines; an array of fuel pumps for pumping gasoline from said storage tanks to said dispenser units; an elongated condensate liquid pickup tube; an elongated inner spout providing a fuel conduit and having an outer tip defining a fuel outlet for discharging gasoline into a filler pipe of a motor vehicle tank during fueling; an outer spout assembly; extending into and engaging said spout-receiving socket, said outer spout assembly comprising an outer spout providing a vapor return conduit and defining apertures providing a vapor inlet spaced from said fuel outlet for withdrawing, removing, and returning a substantial amount of gasoline vapors emitted during said fueling; an elongated liquid sensing tube; a manually operable level; a flow control valve assembly; an automatic shutoff valve assembly; and a venturi sleeve assembly positioned in said venturi sleeve receiving chamber.

  20. The Lithium Vapor Box Divertor

    Science.gov (United States)

    Goldston, Robert; Hakim, Ammar; Hammett, Gregory; Jaworski, Michael; Myers, Rachel; Schwartz, Jacob

    2015-11-01

    Projections of scrape-off layer width to a demonstration power plant suggest an immense parallel heat flux, of order 12 GW/m2, which will necessitate nearly fully detached operation. Building on earlier work by Nagayama et al. and by Ono et al., we propose to use a series of differentially pumped boxes filled with lithium vapor to isolate the buffering vapor from the main plasma chamber, allowing stable detachment. This powerful differential pumping is only available for condensable vapors, not conventional gases. We demonstrate the properties of such a system through conservation laws for vapor mass and enthalpy, and then include plasma entrainment and ultimately an estimate of radiated power. We find that full detachment should be achievable with little leakage of lithium to the main plasma chamber. We also present progress towards solving the Navier-Stokes equation numerically for the chain of vapor boxes, including self-consistent wall boundary conditions and fully-developed shocks, as well as concepts for an initial experimental demonstration-of-concept. This work supported by DOE Contract No. DE-AC02-09CH11466.

  1. Combined effect of carbon dioxide and sulfur on vapor-liquid partitioning of metals in hydrothermal systems

    Science.gov (United States)

    Kokh, Maria A.; Lopez, Mathieu; Gisquet, Pascal; Lanzanova, Aurélie; Candaudap, Frédéric; Besson, Philippe; Pokrovski, Gleb S.

    2016-08-01

    .5-2.0, those of alkali metals are similar to the S-free system, and the partitioning of none of the studied metals is influenced by the presence of CO2 (up to 50 wt% in the vapor). Our data thus confirm the large enhancement of volatility in the presence of reduced sulfur (H2S) due to formation of sulfide complexes for chalcophile metals such as Au, Pt, Mo and, to a lesser extent, Cu and Fe, as reported in previous studies of CO2-free water-salt systems. The negligible effect of CO2 on vapor-liquid partitioning of the studied metals in S-bearing systems is due to the lack of hydration of metal sulfide species making them little sensitive to changes in water activity and solvation power of CO2-H2O vapor. Our findings, combined with existing data over a wide range of temperature on vapor-liquid partitioning of metals in H2O-dominated systems, suggest that CO2 exerts mostly an indirect impact on metal fractionation, by extending vapor-liquid immiscibility to higher temperatures and pressures or depth compared to a CO2-free H2O-S-salt system. The deeper vapor-liquid separation, in particular in S-bearing systems, is expected to cause more significant partitioning of precious metals and molybdenum (Au, Pt, Mo) into the vapor phase while base metals (Fe, Zn, Cu) remain concentrated in the salt-rich (NaCl, KCl) liquid phase. In addition, irrespective of the presence of sulfur, an expansion of the immiscibility domain to higher temperature and pressure conditions in the presence of CO2 will also increase the depth of ore deposition and affect the vertical metal zonation in hydrothermal systems.

  2. Vaporization heat of niobium pentafluoride

    International Nuclear Information System (INIS)

    Literary data on vapor composition above niobium pentafluoride are analyzed and incorrectness of the value of vaporization heat of NbF5 monomeric molecules, given in the Glushko reference book, is shown. Heat capacities of NbF5 gas for monomeric, two-dimensional, three-dimensional and four-dimensional NbF5 molecules are estimated and the vaporization heats of monomeric and polymeric forms at the melting temperature (in kJ/mol): 79.3(5.0)-NbF5, 71.0(6.7)-(NbF5)2, 53.9(4.6)-(NbF5)3, 44.5(6.7)-(NbF5)4, are calculated

  3. Benzene vapor recovery and processing

    International Nuclear Information System (INIS)

    The National Emissions Standards for Hazardous Air Pollutants, or NESHAPs, have provided a powerful motivation for interest in, and attention to, benzene vapor emissions in recent times. Benzene and its related aromatics are volatile organic compounds (VOCs), which marks them for surveillance as potential contributors to air pollution. In addition, benzene is a suspected carcinogen, which applies a special urgency to its control. The regulations governing the control of benzene emissions were issued as Title 40, Code of Federal Regulations, Part 61, subpart Y (Storage Vessels); subpart BB (Transfer Operations); and subpart FF (Waste Operations). These regulations specify very particular emission reduction guidelines for various generating sources. The problem in the hydrocarbon processing industry is to identify significant sources of benzene vapors in plants, and then to collect and process these vapors in an environmentally acceptable manner. This paper discusses various methods for collecting benzene fumes in these facilities

  4. Vapor compression distiller and membrane technology for water revitalization

    Science.gov (United States)

    Ashida, A.; Mitani, K.; Ebara, K.; Kurokawa, H.; Sawada, I.; Kashiwagi, H.; Tsuji, T.; Hayashi, S.; Otsubo, K.; Nitta, K.

    1987-01-01

    Water revitalization for a space station can consist of membrane filtration processes and a distillation process. Water recycling equipment using membrane filtration processes was manufactured for ground testing. It was assembled using commercially available components. Two systems for the distillation are studied: one is absorption type thermopervaporation cell and the other is a vapor compression distiller. Absorption type thermopervaporation, able to easily produce condensed water under zero gravity, was investigated experimentally and through simulated calculation. The vapor compression distiller was studied experimentally and it offers significant energy savings for evaporation of water.

  5. Vaporization of Deforming Droplets

    Science.gov (United States)

    Wang, Yanxing; Chen, Xiaodong; Ma, Dongjun; Yang, Vigor

    2012-11-01

    Droplet deformation is one of the most important factors influencing the evaporation rate. In the present study, high-fidelity numerical simulations of single evaporating droplets with deformation are carried out over a wide range of the Reynolds and Weber numbers. The formulation is based on a complete set of conservation equations for both the liquid and surrounding gas phases. A modified volume-of-fluid (VOF) technique that takes into account heat and mass transfer is used to track the behavior of the liquid/gas interface. Special attention is given to the property conservation, which can be realized by using an iterative algorithm that enforces a divergence constraint in cells containing the interface. The effect of the ambient flow on droplet dynamics and evaporation are investigated systematically. Various underlying mechanisms dictating the droplet characteristics in different deformation regimes are identified. Correlations for the droplet evaporation rate are established in terms of the Reynolds and Weber numbers.

  6. Hydrazine vapor inactivates Bacillus spores

    Science.gov (United States)

    Schubert, Wayne W.; Engler, Diane L.; Beaudet, Robert A.

    2016-05-01

    NASA policy restricts the total number of bacterial spores that can remain on a spacecraft traveling to any planetary body which might harbor life or have evidence of past life. Hydrazine, N2H4, is commonly used as a propellant on spacecraft. Hydrazine as a liquid is known to inactivate bacterial spores. We have now verified that hydrazine vapor also inactivates bacterial spores. After Bacillus atrophaeus ATCC 9372 spores deposited on stainless steel coupons were exposed to saturated hydrazine vapor in closed containers, the spores were recovered from the coupons, serially diluted, pour plated and the surviving bacterial colonies were counted. The exposure times required to reduce the spore population by a factor of ten, known as the D-value, were 4.70 ± 0.50 h at 25 °C and 2.85 ± 0.13 h at 35 °C. These inactivation rates are short enough to ensure that the bioburden of the surfaces and volumes would be negligible after prolonged exposure to hydrazine vapor. Thus, all the propellant tubing and internal tank surfaces exposed to hydrazine vapor do not contribute to the total spore count.

  7. Simple Chemical Vapor Deposition Experiment

    Science.gov (United States)

    Pedersen, Henrik

    2014-01-01

    Chemical vapor deposition (CVD) is a process commonly used for the synthesis of thin films for several important technological applications, for example, microelectronics, hard coatings, and smart windows. Unfortunately, the complexity and prohibitive cost of CVD equipment makes it seldom available for undergraduate chemistry students. Here, a…

  8. Enhanced Haze Ratio on Glass by Novel Vapor Texturing Method.

    Science.gov (United States)

    Lee, Seunghwan; Balaji, Nagarajan; Ju, Minkyu; Park, Cheolmin; Kim, Jungmo; Chung, Sungyoun; Lee, Youn-Jung

    2016-05-01

    State-of-the-art optical trapping designs are required to enhance the light trapping capabilities of tandem thin film silicon solar cells. The wet etch process is used to texture the glass surface by dipping in diluted acidic solutions such as HNO3 (nitric acid) and HF (hydrofluoric acid). For vapor texturing, the vapor was generated by adding silicon to HF:HNO3 acidic solution. The anisotropic etching of vapor textured wafers resulted in an etching depth of about 2.78 μm with reduced reflectance of 5%. We achieved a high haze value of 74.6% at a 540 nm wavelength by increasing the etching time and HF concentration. PMID:27483862

  9. Remote sensing of water vapor features

    Science.gov (United States)

    Fuelberg, Henry E.

    1991-01-01

    The three major objectives of the project are outlined: (1) to describe atmospheric water vapor features as functions of space and time; (2) to evaluate remotely sensed measurements of water vapor content; and (3) to study relations between fine-scale water vapor fields and convective activity. Data from several remote sensors were used. The studies used the GOES/VAS, HIS, and MAMS instruments have provided a progressively finer scale view of water vapor features.

  10. Hanford soil partitioning and vapor extraction study

    International Nuclear Information System (INIS)

    This report describes the testing and results of laboratory experiments conducted to assist the carbon tetrachloride soil vapor extraction project operating in the 200 West Area of the Hanford Site in Richland, Washington. Vapor-phase adsorption and desorption testing was performed using carbon tetrachloride and Hanford Site soils to estimate vapor-soil partitioning and reasonably achievable carbon tetrachloride soil concentrations during active vapor extractions efforts at the 200 West Area. (CCl4 is used in Pu recovery from aqueous streams.)

  11. Vapor Pressure Measurements in a Closed System

    Science.gov (United States)

    Iannone, Mark

    2006-01-01

    An alternative method that uses a simple apparatus to measure vapor pressure versus temperature in a closed system, in which the total pressure is the vapor pressure of the liquid sample, is described. The use of this apparatus gives students a more direct picture of vapor pressure than the isoteniscope method and results have generally been quite…

  12. Vapor Pressure Plus: An Experiment for Studying Phase Equilibria in Water, with Observation of Supercooling, Spontaneous Freezing, and the Triple Point

    Science.gov (United States)

    Tellinghuisen, Joel

    2010-01-01

    Liquid-vapor, solid-vapor, and solid-liquid-vapor equilibria are studied for the pure substance water, using modern equipment that includes specially fabricated glass cells. Samples are evaporatively frozen initially, during which they typically supercool to -5 to -10 [degrees]C before spontaneously freezing. Vacuum pumping lowers the temperature…

  13. Active Hydrazine Vapor Sampler (AHVS)

    Science.gov (United States)

    Young, Rebecca C.; Mcbrearty, Charles F.; Curran, Daniel J.

    1993-01-01

    The Active Hydrazine Vapor Sampler (AHVS) was developed to detect vapors of hydrazine (HZ) and monomethylhydrazine (MMH) in air at parts-per-billion (ppb) concentration levels. The sampler consists of a commercial personal pump that draws ambient air through paper tape treated with vanillin (4-hydroxy-3-methoxybenzaldehyde). The paper tape is sandwiched in a thin cardboard housing inserted in one of the two specially designed holders to facilitate sampling. Contaminated air reacts with vanillin to develop a yellow color. The density of the color is proportional to the concentration of HZ or MMH. The AHVS can detect 10 ppb in less than 5 minutes. The sampler is easy to use, low cost, and intrinsically safe and contains no toxic material. It is most beneficial for use in locations with no laboratory capabilities for instrumentation calibration. This paper reviews the development, laboratory test, and field test of the device.

  14. Vapor stabilizing surfaces for superhydrophobicity

    Science.gov (United States)

    Patankar, Neelesh

    2010-11-01

    The success of rough substrates designed for superhydrophobicity relies crucially on the presence of air pockets in the roughness grooves. This air is supplied by the surrounding environment. However, if the rough substrates are used in enclosed configurations, such as in fluidic networks, the air pockets may not be sustained in the roughness grooves. In this work a design approach based on sustaining a vapor phase of the liquid in the roughness grooves, instead of relying on the presence of air, is explored. The resulting surfaces, referred to as vapor stabilizing substrates, are deemed to be robust against wetting transition even if no air is present. Applications of this approach include low drag surfaces, nucleate boiling, and dropwise condensation heat transfer, among others.

  15. Vapor fraction distribution within pipelines and channels

    International Nuclear Information System (INIS)

    Three-dimensional distribution of vapor volumetric fractions in subcooled boiling is analyzed for circular tubes and rectangular channels. The model is based on three major assumptions: 1) vapor bubble mation is controlled by diffusion due to flow turbulence; 2) the diffusion coefficient and bubble velocity are constant within the channel cross-section as well as the coolant temperature; 3) the vapor bubble generation and condensation rates are calculated according to one-dimensional models. The vapor void distribution is obtained from an analytical solution of the vapor bubble diffusion equation with a simplified approximation of subcooling profile. A method of boundary conditions formulation for the diffusin equation is also presented

  16. High temperature vapors science and technology

    CERN Document Server

    Hastie, John

    2012-01-01

    High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

  17. Vapor deposition of tantalum and tantalum compounds

    International Nuclear Information System (INIS)

    Tantalum, and many of its compounds, can be deposited as coatings with techniques ranging from pure, thermal chemical vapor deposition to pure physical vapor deposition. This review concentrates on chemical vapor deposition techniques. The paper takes a historical approach. The authors review classical, metal halide-based techniques and current techniques for tantalum chemical vapor deposition. The advantages and limitations of the techniques will be compared. The need for new lower temperature processes and hence new precursor chemicals will be examined and explained. In the last section, they add some speculation as to possible new, low-temperature precursors for tantalum chemical vapor deposition

  18. Equilibrium solubilities of iodine vapor in water

    International Nuclear Information System (INIS)

    Equilibrium solubilities of iodine vapor in water were measured by introducing iodine vapor, in equilibrium with solid iodine, into water and by circulating it in a closed system, and Henry's law constants were determined. Equilibrium distributions of iodine vapor between a gas phase and an aqueous phase were also measured by another method, and partition coefficients were determined. The solubilities of iodine vapor in water estimated from both the Henry's law constants and the partition coefficients are compared with those of solid iodine reported in the literature. Thermodynamic parameters for the hydration of iodine vapor are evaluated experimentally. (author)

  19. Vaporization of In2Te3(s)

    International Nuclear Information System (INIS)

    The vaporization chemistry of In2Te3(s) was studied by the computerautomated simultaneous Knudsen-effusion and torsion-effusion method, by high-temperature mass spectrometry, and by ancillary methods. The first absolute measurements of the vapor pressure of In2Te3 are reported. In2Te3(s) vaporized incongruently in the temperatue range 701-889 K and produced Te2(g) and a solid-solution, (Xsub(In)=0.42 and Xsub(Te)=0.58). The standard enthalpy of the reaction at 298 K, ΔH0 (298 K) by the third-law method was 136.0 +- 0.3 kJ/mol of vapor. The above solid solution vaporized incongruently and produced in InTe(s) and a vapor which consisted of Te2(g) and In2Te(g). InTe(s) vaporized congruently in the range 701-887 K and produded Te2(g) and In2Te(g); the third-law ΔH0sub(ν) (298 K) was 201.5 +- 1.0 kJ/mol. These results were at variance with the literature on vaporization of In2Te3(s) where both congruent vaporization and incongruent vaporization to give InTe(s) are separately reported. Further, InTe(s) was reported to vaporize incongruently. These differences are discussed. (Author)

  20. Dichroic atomic vapor laser lock with multi-gigahertz stabilization range

    CERN Document Server

    Pustelny, S; Sholtes, T; Budker, D

    2015-01-01

    A dichroic atomic vapor laser lock (DAVLL) system exploiting buffer-gas-filled millimeter-scale vapor cells is presented. This system offers similar stability as achievable with bulk vapor cells, but has several important advantages. In addition to its compactness, it may provide continuous stabilization in a multi-gigahertz range around the optical transition. This range may be controlled either by changing the temperature of the vapor or by application of a buffer gas under an appropriate pressure. In particular, we show that the DAVLL system with a buffer-gas cell enables locking the laser frequency between two hyperfine components of the $^{85}$Rb ground state or as far as 16 GHz away from the closest optical transition.

  1. Triggered vaporization of gold nanodroplets for enhanced photothermal therapy

    Science.gov (United States)

    Liu, Shu-Wei; Liu, Wei-Wen; Li, Pai-Chi

    2015-03-01

    Acoustic droplet vaporization has been proposed for sonoporation. In this study, we hypothesize that, by using gold nanodroplets (AuNDs), vaporization can be triggered with external application of laser irradiation. In addition, the vaporization assisted sonoporation can enhance delivery of gold nanoparticles (AuNPs) into the cells, thus potentially enhancing effects of plasmonic photothermal therapy. To test our hypothesis, in vitro studies were conducted. The delivery efficiency of AuNDs was also compared to that of AuNPs encapsulated in ultrasound microbubbles (AuMBs). The inertial cavitation dose (ICD), and optical density (OD) value of AuNPs were all measured under the applications of ultrasound only, laser only, and both ultrasound and laser. Results show that the cavitational effects and microbubble destruction were the highest with both ultrasound and laser being applied. In addition, destruction ratio of AuNDs was around 43%, compared to 35% microbubble destruction of AuMBs. Likewise, the OD value of AuNDs is 1.3 times higher than that of AuMBs under the same conditions, indicating that cavitation resulting from microbubble destruction did have the capability to assist the delivery of AuNPs into the cells. After the delivery, laser heating resulted in cell death. The cell viability with AuNDs was 45% left in the in vitro studies. Synergistic effects were also evident when combing laser with ultrasound.

  2. Performances of electrically heated microgroove vaporizers

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An electrically heated microgroove vaporizer was proposed. The vaporizer mainly comprised an outer tube, an inner tube and an electrical heater cartridge. Microgrooves were fabricated on the external surface of the inner tube by micro-cutting method,which formed the flow passage for fluid between the external surface of the inner tube and the internal surface of the outer tube.Experiments related to the temperature rise response of water and the thermal conversion efficiency of vaporizer were done to estimate the influences of microgroove's direction, feed flow rate and input voltage on the performances of the vaporizer. The results indicate that the microgroove's direction dominates the vaporizer performance at a lower input voltage. The longitudina lmicrogroove vaporizer exhibits the best performances for the temperature rise response of water and thermal conversion efficiency of vaporizer. For a moderate input voltage, the microgroove's direction and the feed flow rate of water together govern the vaporizer performances. The input voltage becomes the key influencing factor when the vaporizer works at a high input voltage, resulting in the similar performances of longitudinal, oblique and latitudinal microgroove vaporizers.

  3. Atomic vapor laser isotope separation

    Science.gov (United States)

    Paisner, J. A.

    1988-07-01

    Atomic Vapor Laser Isotope Separation (AVLIS) is a general and powerful technique applicable to many elements. A major present application to the enrichement of uranium for lightwater power reactor fuel has been under development at the Lawrence Livermore National Laboratory since 1973. In June 1985, the Department of Energy announced the selection of AVLIS as the technology to meet future U.S. needs for the internationally competitive production of uranium separative work. Major features of the AVLIS process will be discussed with consideration of the process figures of merit.

  4. Thermogravimetric measurements of liquid vapor pressure

    International Nuclear Information System (INIS)

    Highlights: ► Rapid determination of vapor pressure by TGA. ► Demonstration of limitations of currently available approaches in literature. ► New model for vapor pressure assessment of small size samples in TGA. ► New model accounts for vapor diffusion and sample geometry and measures vapor pressure normally within 10%. - Abstract: A method was developed using thermo-gravimetric analysis (TGA) to determine the vapor pressure of volatile liquids. This is achieved by measuring the rate of evaporation (mass loss) of a pure liquid contained within a cylindrical pan. The influence of factors like sample geometry and vapor diffusion on evaporation rate are discussed. The measurement can be performed across a wide range of temperature yielding reasonable results up to 10 kPa. This approach may be useful as a rapid and automatable method for measuring the volatility of flavor and fragrance raw materials.

  5. Mechanisms regulating tropical tropospheric water vapor

    Science.gov (United States)

    Dessler, A. E.; Minschwaner, K.

    2005-12-01

    We have analyzed tropical water vapor measurements made in the mid and upper troposphere by the Atmospheric Infrared Sounder (AIRS) onboard NASA's Aqua satellite. We compare the water vapor measurements to a simple trajectory simulation of water vapor, and show reasonable agreement. We conclude, in agreement with previous work, that the large-scale circulation is primarily responsible for the distribution of water vapor. By interpreting disagreements between AIRS and the model as being caused by processes not represented in the model, such as detailed microphysics, we can begin to get some idea of where in the atmosphere these missing processes are important.

  6. Development of Field-deployable Diode-laser-based Water Vapor Dial

    Directory of Open Access Journals (Sweden)

    Le Hoai Phong Pham

    2016-01-01

    Full Text Available In this paper, a field-deployable diode-laser-based differential absorption lidar (DIAL has been developed for lower-tropospheric water vapor observation in Tokyo, Japan. A photoacoustic cell is used for spectroscopy experiment around absorption peaks of 829.022 nm and 829.054 nm. The water vapor density extracted from the observational data agrees with the referenced radiosonde data. Furthermore, we applied modulated pulse technique for DIAL transmitter. It enables DIAL to measure water vapor profile for both low and high altitude regions.

  7. 40 CFR Table 6 to Subpart IIIii of... - Examples of Techniques for Equipment Problem Identification, Leak Detection and Mercury Vapor

    Science.gov (United States)

    2010-07-01

    ... Problem Identification, Leak Detection and Mercury Vapor 6 Table 6 to Subpart IIIII of Part 63 Protection... Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali Plants Pt. 63, Subpt. IIIII..., Leak Detection and Mercury Vapor As stated in Tables 1 and 2 of Subpart IIIII, examples of...

  8. Influence of Soil Moisture on Soil Gas Vapor Concentration for Vapor Intrusion

    OpenAIRE

    Shen, Rui; Pennell, Kelly G.; Suuberg, Eric M.

    2013-01-01

    Mathematical models have been widely used in analyzing the effects of various environmental factors in the vapor intrusion process. Soil moisture content is one of the key factors determining the subsurface vapor concentration profile. This manuscript considers the effects of soil moisture profiles on the soil gas vapor concentration away from any surface capping by buildings or pavement. The “open field” soil gas vapor concentration profile is observed to be sensitive to the soil moisture di...

  9. Device for the detection of acid vapors and particularly hydrofluoric acid vapors

    International Nuclear Information System (INIS)

    This device concerns the detection of acid vapors contained in a gaseous environment which have to be controlled. It uses a detector with a calorimetric material. It can be used to detect acid vapors, but it detects particularly hydrofluoric acid vapors. In nuclear industry, this device can detect hydrofluoric acid from UF6, even at high temperature. (TEC)

  10. Investigations on atomic-vapor-filter high-spectral-resolution lidar for temperature measurements

    Science.gov (United States)

    Voss, E.; Weitkamp, C.

    1992-01-01

    The temperature measurement by the analysis of Rayleigh scattered laser radiation with atomic vapor filters is investigated in both theory and laboratory experiments. Synthetic air is irradiated with a cw dye laser at 283 nano-meters, and the backscattered spectrum is analyzed with two lead vapor cells in one oven. Temperature measurements are carried out, and the effect of different parameters on the accuracy is investigated. Important aspects for the realization of a lidar are given.

  11. Optical Sensor for Diverse Organic Vapors at ppm Concentration Ranges

    Directory of Open Access Journals (Sweden)

    Dora M. Paolucci

    2011-03-01

    Full Text Available A broadly responsive optical organic vapor sensor is described that responds to low concentrations of organic vapors without significant interference from water vapor. Responses to several classes of organic vapors are highlighted, and trends within classes are presented. The relationship between molecular properties (vapor pressure, boiling point, polarizability, and refractive index and sensor response are discussed.

  12. Soil vapor extraction with dewatering

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, N.R. [Univ. of Waterloo, Ontario (Canada)

    1996-08-01

    The physical treatment technology of soil vapor extraction (SVE) is reliable, safe, robust, and able to remove significant amounts of mass at a relatively low cost. SVE combined with a pump-and-treat system to create a dewatered zone has the opportunity to remove more mass with the added cost of treating the extracted groundwater. Various limiting processes result in a significant reduction in the overall mass removal rates from a SVE system in porous media. Only pilot scale, limited duration SVE tests conducted in low permeability media have been reported in the literature. It is expected that the presence of a fracture network in low permeability media will add another complexity to the limiting conditions surrounding the SVE technology. 20 refs., 4 figs.

  13. Risk assessment of metal vapor arcing

    Science.gov (United States)

    Hill, Monika C. (Inventor); Leidecker, Henning W. (Inventor)

    2009-01-01

    A method for assessing metal vapor arcing risk for a component is provided. The method comprises acquiring a current variable value associated with an operation of the component; comparing the current variable value with a threshold value for the variable; evaluating compared variable data to determine the metal vapor arcing risk in the component; and generating a risk assessment status for the component.

  14. Boron carbide whiskers produced by vapor deposition

    Science.gov (United States)

    1965-01-01

    Boron carbide whiskers have an excellent combination of properties for use as a reinforcement material. They are produced by vaporizing boron carbide powder and condensing the vapors on a substrate. Certain catalysts promote the growth rate and size of the whiskers.

  15. Vapor Pressures of Several Commercially Used Alkanolamines

    NARCIS (Netherlands)

    Klepacova, Katarina; Huttenhuis, Patrick J. G.; Derks, Peter W. J.; Versteeg, Geert F.; Klepáčová, Katarína

    2011-01-01

    For the design of acid gas treating processes, vapor-liquid equilibrium (VLE) data must be available of the solvents to be applied. In this study the vapor pressures of seven frequently industrially used alkanolamines (diethanolamine, N-methylethanolamine, N,N-dimethylethanolamine, N,N-diethylethano

  16. Quantum memory in warm rubidium vapor with buffer gas

    CERN Document Server

    Bashkansky, Mark; Vurgaftman, Igor

    2011-01-01

    The realization of quantum memory using warm atomic vapor cells is appealing because of their commercial availability and the perceived reduction in experimental complexity. In spite of the ambiguous results reported in the literature, we demonstrate that quantum memory can be implemented in a single cell with buffer gas using the geometry where the write and read beams are nearly co-propagating. The emitted Stokes and anti-Stokes photons display cross-correlation values greater than 2, characteristic of quantum states, for delay times up to 4 microseconds.

  17. Vapor-barrier Vacuum Isolation System

    Science.gov (United States)

    Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)

    2014-01-01

    A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. Pressure levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric vapor from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing vapor to a boundary with the working chamber, and supersonically expanding the vapor as it enters the isolation chambers via the orifices. The vapor condenses in each isolation chamber using the cooling material, and uncondensed vapor is pumped out of the isolation chambers via the pump.

  18. Microbial growth with vapor-phase substrate

    Energy Technology Data Exchange (ETDEWEB)

    Hanzel, Joanna; Thullner, Martin; Harms, Hauke [UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig (Germany); Wick, Lukas Y., E-mail: lukas.wick@ufz.de [UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstrasse 15, 04318 Leipzig (Germany)

    2011-04-15

    Limited information exists on influences of the diffusive transport of volatile organic contaminants (VOC) on bacterial activity in the unsaturated zone of the terrestrial subsurface. Diffusion of VOC in the vapor-phase is much more efficient than in water and results in effective VOC transport and high bioavailability despite restricted mobility of bacteria in the vadose zone. Since many bacteria tend to accumulate at solid-water, solid-air and air-water interfaces, such phase boundaries are of a special interest for VOC-biodegradation. In an attempt to evaluate microbial activity toward air-borne substrates, this study investigated the spatio-temporal interplay between growth of Pseudomonas putida (NAH7) on vapor-phase naphthalene (NAPH) and its repercussion on vapor-phase NAPH concentrations. Our data demonstrate that growth rates of strain PpG7 were inversely correlated to the distance from the source of vapor-phase NAPH. Despite the high gas phase diffusivity of NAPH, microbial growth was absent at distances above 5 cm from the source when sufficient biomass was located in between. This indicates a high efficiency of suspended bacteria to acquire vapor-phase compounds and influence headspace concentration gradients at the centimeter-scale. It further suggests a crucial role of microorganisms as biofilters for gas-phase VOC emanating from contaminated groundwater or soil. - Research highlights: > Suspended bacteria have a high efficiency to degrade vapor-phase naphthalene. > Bacteria influence NAPH vapor-phase concentration gradients at centimeter-scale. > Microbial growth on vapor-phase naphthalene is inversely correlated to its source. > Bacteria are good biofilters for gas-phase NAPH emanating from contaminated sites. - Suspended bacteria have a high efficiency to degrade vapor-phase naphthalene and effectively influence vapor-phase naphthalene concentration gradients at the centimeter scale.

  19. HANFORD CHEMICAL VAPORS WORKER CONCERNS & EXPOSURE EVALUATION

    Energy Technology Data Exchange (ETDEWEB)

    ANDERSON, T.J.

    2006-12-20

    Chemical vapor emissions from underground hazardous waste storage tanks on the Hanford site in eastern Washington State are a potential concern because workers enter the tank farms on a regular basis for waste retrievals, equipment maintenance, and surveillance. Tank farm contractors are in the process of retrieving all remaining waste from aging single-shell tanks, some of which date to World War II, and transferring it to newer double-shell tanks. During the waste retrieval process, tank farm workers are potentially exposed to fugitive chemical vapors that can escape from tank headspaces and other emission points. The tanks are known to hold more than 1,500 different species of chemicals, in addition to radionuclides. Exposure assessments have fully characterized the hazards from chemical vapors in half of the tank farms. Extensive sampling and analysis has been done to characterize the chemical properties of hazardous waste and to evaluate potential health hazards of vapors at the ground surface, where workers perform maintenance and waste transfer activities. Worker concerns. risk communication, and exposure assessment are discussed, including evaluation of the potential hazards of complex mixtures of chemical vapors. Concentrations of vapors above occupational exposure limits-(OEL) were detected only at exhaust stacks and passive breather filter outlets. Beyond five feet from the sources, vapors disperse rapidly. No vapors have been measured above 50% of their OELs more than five feet from the source. Vapor controls are focused on limited hazard zones around sources. Further evaluations of vapors include analysis of routes of exposure and thorough analysis of nuisance odors.

  20. Differential absorption radar techniques: water vapor retrievals

    Science.gov (United States)

    Millán, Luis; Lebsock, Matthew; Livesey, Nathaniel; Tanelli, Simone

    2016-06-01

    Two radar pulses sent at different frequencies near the 183 GHz water vapor line can be used to determine total column water vapor and water vapor profiles (within clouds or precipitation) exploiting the differential absorption on and off the line. We assess these water vapor measurements by applying a radar instrument simulator to CloudSat pixels and then running end-to-end retrieval simulations. These end-to-end retrievals enable us to fully characterize not only the expected precision but also their potential biases, allowing us to select radar tones that maximize the water vapor signal minimizing potential errors due to spectral variations in the target extinction properties. A hypothetical CloudSat-like instrument with 500 m by ˜ 1 km vertical and horizontal resolution and a minimum detectable signal and radar precision of -30 and 0.16 dBZ, respectively, can estimate total column water vapor with an expected precision of around 0.03 cm, with potential biases smaller than 0.26 cm most of the time, even under rainy conditions. The expected precision for water vapor profiles was found to be around 89 % on average, with potential biases smaller than 77 % most of the time when the profile is being retrieved close to surface but smaller than 38 % above 3 km. By using either horizontal or vertical averaging, the precision will improve vastly, with the measurements still retaining a considerably high vertical and/or horizontal resolution.

  1. Manipulating the Morphology of P3HT–PCBM Bulk Heterojunction Blends with Solvent Vapor Annealing

    KAUST Repository

    Verploegen, Eric

    2012-10-23

    Using grazing incidence X-ray scattering, we observe the effects of solvent vapors upon the morphology of poly(3-hexylthiophene)-phenyl-C 61-butyric acid methyl ester (P3HT-PCBM) bulk heterojunction thin film blends in real time; allowing us to observe morphological rearrangements that occur during this process as a function of solvent. We detail the swelling of the P3HT crystallites upon the introduction of solvent and the resulting changes in the P3HT crystallite morphology. We also demonstrate the ability for tetrahydrofuran vapor to induce crystallinity in PCBM domains. Additionally, we measure the nanoscale phase segregated domain size as a function of solvent vapor annealing and correlate this to the changes observed in the crystallite morphology of each component. Finally, we discuss the implications of the morphological changes induced by solvent vapor annealing on the device properties of BHJ solar cells. © 2012 American Chemical Society.

  2. The vapor pressure of iron pentacarbonyl

    Science.gov (United States)

    Gilbert, A. G.; Sulzmann, K. G. P.

    1974-01-01

    Vapor pressure measurements have been made on pure iron pentacarbonyl between +31 and -19 C. The experimental results may be expressed by the logarithm of pressure (mm Hg) to the base 10 equals -(2096.7 K/T) + 8.4959, which corresponds to a heat of vaporization for the liquid carbonyl of delta H ? (9.588 plus or minus 0.12) kcal/mole. This result confirms and extends the earlier measurements made by Trautz and Badstuebner between 0 and 140 C. The need for careful purification of commercially available iron pentacarbonyl is emphasized, particularly for establishing the correct vapor pressure below 45 C.

  3. Reduction of Legionella spp. in water and in soil by a citrus plant extract vapor.

    Science.gov (United States)

    Laird, Katie; Kurzbach, Elena; Score, Jodie; Tejpal, Jyoti; Chi Tangyie, George; Phillips, Carol

    2014-10-01

    Legionnaires' disease is a severe form of pneumonia caused by Legionella spp., organisms often isolated from environmental sources, including soil and water. Legionella spp. are capable of replicating intracellularly within free-living protozoa, and once this has occurred, Legionella is particularly resistant to disinfectants. Citrus essential oil (EO) vapors are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml(-1) on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapor against Legionella spp. in water and in soil systems. Reductions of viable cells of Legionella pneumophila, Legionella longbeachae, Legionella bozemanii, and an intra-amoebal culture of Legionella pneumophila (water system only) were assessed in soil and in water after exposure to a citrus EO vapor at concentrations ranging from 3.75 mg/liter air to 15g/liter air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapor) was determined in water, and gas chromatography-mass spectrometry (GC-MS) analysis of the antimicrobial components (linalool, citral, and β-pinene) was conducted. There was up to a 5-log cells ml(-1) reduction in Legionella spp. in soil after exposure to the citrus EO vapors (15 mg/liter air). The most susceptible strain in water was L. pneumophila, with a 4-log cells ml(-1) reduction after 24 h via sintering (15 g/liter air). Sintering the vapor through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapor may go some way in controlling Legionella spp. from environmental sources. PMID:25063652

  4. 40 CFR 61.51 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... heat to extract mercury metal from mercury ore. (e) Mercury chlor-alkali cell means a device which is... produce chlorine gas, hydrogen gas, and alkali metal hydroxide. (f) Mercury chlor-alkali electrolyzer... container which is part of a mercury chlor-alkali cell and in which water and alkali metal amalgam...

  5. E-Cigarettes Emit Toxic Vapors

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_160107.html E-Cigarettes Emit Toxic Vapors: Study Levels depend on ... findings could be important to both makers of e-cigarettes and regulators who want to reduce the ...

  6. DMSP SSMT/2 - Atmospheric Water Vapor Profiler

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SSM/T-2 sensor is a five channel, total power microwave radiometer with three channels situated symmetrically about the 183.31 GHz water vapor resonance line...

  7. Remote sensing of water vapor features

    Science.gov (United States)

    Fuelberg, Henry E.

    1993-01-01

    Water vapor plays a critical role in the atmosphere. It is an important medium of energy exchange between air, land, and water; it is a major greenhouse gas, providing a crucial radiative role in the global climate system; and it is intimately involved in many regional scale atmospheric processes. Our research has been aimed at improving satellite remote sensing of water vapor and better understanding its role in meteorological processes. Our early studies evaluated the current GOES VAS system for measuring water vapor and have used VAS-derived water vapor data to examine pre-thunderstorm environments. Much of that research was described at the 1991 Research Review. A second research component has considered three proposed sensors--the High resolution Interferometer Sounder (HIS), the Multispectral Atmospheric Mapping Sensor (MAMS), and the Advanced Microwave Sounding Unit (AMSU). We have focused on MAMS and AMSU research during the past year and the accomplishments made in this effort are presented.

  8. Static Water Vapor Feed Electrolyzer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of a static vapor feed electrolyzer utilizing an advanced bipolar plate that produces sub-saturated H2 and O2 is proposed. This novel bipolar design can...

  9. External fuel vaporization study, phase 1

    Science.gov (United States)

    Szetela, E. J.; Chiappetta, L.

    1980-01-01

    A conceptual design study was conducted to devise and evaluate techniques for the external vaporization of fuel for use in an aircraft gas turbine with characteristics similar to the Energy Efficient Engine (E(3)). Three vaporizer concepts were selected and they were analyzed from the standpoint of fuel thermal stability, integration of the vaporizer system into the aircraft engine, engine and vaporizer dynamic response, startup and altitude restart, engine performance, control requirements, safety, and maintenance. One of the concepts was found to improve the performance of the baseline E(3) engine without seriously compromising engine startup and power change response. Increased maintenance is required because of the need for frequent pyrolytic cleaning of the surfaces in contact with hot fuel.

  10. Vapor Hydrogen Peroxide Sterilization Certification

    Science.gov (United States)

    Chen, Fei; Chung, Shirley; Barengoltz, Jack

    For interplanetary missions landing on a planet of potential biological interest, United States NASA planetary protection currently requires that the flight system must be assembled, tested and ultimately launched with the intent of minimizing the bioload taken to and deposited on the planet. Currently the only NASA approved microbial reduction method is dry heat sterilization process. However, with utilization of such elements as highly sophisticated electronics and sensors in modern spacecraft, this process presents significant materials challenges and is thus an undesirable bioburden reduction method to design engineers. The objective of this work is to introduce vapor hydrogen peroxide (VHP) as an alternative to dry heat microbial reduction to meet planetary protection requirements. The VHP sterilization technology is widely used by the medical industry, but high doses of VHP may degrade the performance of flight hardware, or compromise material compatibility. The goal of our study is determine the minimum VHP process conditions for PP acceptable microbial reduction levels. A series of experiments were conducted using Geobacillus stearothermophilus to determine VHP process parameters that provided significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. In addition to the obvious process parameters -hydrogen peroxide concentration, number of pulses, and exposure duration -the investigation also considered the possible effect of environmental pa-rameters. Temperature, relative humidity, and material substrate effects on lethality were also studied. Based on the results, a most conservative D value was recommended. This recom-mended D value was also validated using VHP "hardy" strains that were isolated from clean-rooms and environmental populations collected from spacecraft relevant areas. The efficiency of VHP at ambient condition as well as VHP material compatibility will also be

  11. Modelling vaporous cavitation on fluid transients

    OpenAIRE

    Shu, Jian-Jun

    2014-01-01

    A comprehensive study of the problem of modelling vaporous cavitation in transmission lines is presented. The two-phase homogeneous equilibrium vaporous cavitation model which has been developed is compared with the conventional column separation model. The latter predicts unrealistically high pressure spikes because of a conflict arising from the prediction of negative cavity sizes if the pressure is not permitted to fall below the vapour pressure, or the prediction of negative absolute pres...

  12. Binary Schemes of Vapor Bubble Growth

    Science.gov (United States)

    Zudin, Yu. B.

    2015-05-01

    A problem on spherically symmetric growth of a vapor bubble in an infi nite volume of a uniformly superheated liquid is considered. A description of the limiting schemes of bubble growth is presented. A binary inertial-thermal bubble growth scheme characterized by such specifi c features as the "three quarters" growth law and the effect of "pressure blocking" in a vapor phase is considered.

  13. Urania vapor composition at very high temperatures

    International Nuclear Information System (INIS)

    Due to the chemically unstable nature of uranium dioxide its vapor composition at very high temperatures is, presently, not sufficiently studied though more experimental knowledge is needed for risk assessment of nuclear reactors. We used laser vaporization coupled to mass spectrometry of the produced vapor to study urania vapor composition at temperatures in the vicinity of its melting point and higher. The very good agreement between measured melting and freezing temperatures and between partial pressures measured on the temperature increase and decrease indicated that the change in stoichiometry during laser heating was very limited. The evolutions with temperature (in the range 2800-3400 K) of the partial pressures of the main vapor species (UO2, UO3, and UO2+) were compared with theoretically predicted evolutions for equilibrium noncongruent gas-liquid and gas-solid phase coexistences and showed very good agreement. The measured main relative partial pressure ratios around 3300 K all agree with calculated values for total equilibrium between condensed and vapor phases. It is the first time the three main partial pressure ratios above stoichiometric liquid urania have been measured at the same temperature under conditions close to equilibrium noncongruent gas-liquid phase coexistence.

  14. A mass spectrometric study of the vaporization of boron phosphate (BPO(4))

    Science.gov (United States)

    Lopatin; Semenov

    1999-01-01

    The vaporization behavior of boron phosphate has been studied by using Knudsen effusion mass spectrometry. The vapor over BPO(4) consists of B(2)O(3), P(4)O(10), PO(2), BPO(4) (platinum cell) and B(2)O(3), PO, PO(2), BPO(3), BPO(4) (molybdenum cell). Standard enthalpies of formation and atomization (kJ/mol) were derived for BPO(4) (g) (-1000 +/- 15 and 2863 +/- 16) and for BPO(3) (g) (-731 +/- 15 and 2347 +/- 16), respectively. Copyright 1999 John Wiley & Sons, Ltd.

  15. An optical water vapor sensor for unmanned aerial vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Timothy A. Berkoff; Paul L. Kebabian; Robert A. McClatchy; Charles E. Kolb; Andrew Freedman

    1998-12-01

    The water vapor sensor developed by Aerodyne Research, based on the optical absorption of light at {approximately}935 nm, has been successfully demonstrated on board the Pacific Northwest National Laboratory's Gulfstream-1 research aircraft during the Department of Energy's ARM Intensive Operations Period in August 1998. Data taken during this field campaign show excellent agreement with a chilled mirror and Lyman-alpha hygrometers and measurements confirm the ability to measure rapid, absolute water vapor fluctuations with a high degree of instrument stability and accuracy, with a noise level as low 10 ppmv (1 Hz measurement bandwidth). The construction of this small, lightweight sensor contains several unique elements which result in several significant advantages when compared to other techniques. First, the low power consumption Argon discharge lamp provides an optical beam at a fixed wavelength without a need for temperature or precision current control. The multi-pass absorption cell developed for this instrument provides a compact, low cost method that can survive deployment in the field. Fiber-optic cables, which are used to convey to light between the absorption cell, light source, and detection modules enable remote placement of the absorption cell from the opto-electronics module. Finally, the sensor does not use any moving parts which removes a significant source of potential malfunction. The result is an instrument which maintained its calibration throughout the field measurement campaign, and was not affected by high vibration and large uncontrolled temperature excursions. We believe that the development of an accurate, fast response water vapor monitor described in this report will open up new avenues of aerial-vehicle-based atmospheric research which have been relatively unexplored due to the lack of suitable low-cost, light-weight instrumentation.

  16. Hydrothermal synthesis of mixed rare earth-alkali metal or ammonium fluorides

    Institute of Scientific and Technical Information of China (English)

    由芳田; 黄世华; 时秋峰

    2010-01-01

    The recent results on hydrothermal synthesis of mixed rare earth-alkali or ammonium fluorides were presented. The initial ratios of the starting materials, pH value and reaction temperature were the critical factors for obtaining the single-phase product. Four main types of complex rare earth fluorides, AREF4, A2REF5, ARE2F7 and ARE3F10 (A=Na+, K+, Rb+, NH4+), appeared in the primary hydrothermal reactions. The correlation between cation sizes and the formation of mixed rare earth fluorides under mild hydro...

  17. Explorations of New SHG Materials in the Alkali-Metal-Nb(5+)-Selenite System.

    Science.gov (United States)

    Cao, Xue-Li; Hu, Chun-Li; Kong, Fang; Mao, Jiang-Gao

    2015-11-16

    Standard high-temperature solid-state reactions of NaCl, Nb2O5, and SeO2 resulted in two new sodium selenites containing a second-order Jahn-Teller (SOJT) distorted Nb(5+) cation, namely, Na2Nb4O7(SeO3)4 (P1̅; 1) and NaNbO(SeO3)2 (Cmc21; 2). Compound 1 exhibits an unusual 3D [Nb4O7(SeO3)4](2-) anionic network composed of 2D [Nb4O11(SeO3)2](6-) layers which are further bridged by additional SeO3(2-) anions via corner sharing; the 2D [Nb4O11(SeO3)2](6-) layer is formed by unusual quadruple [Nb4O17](14-) niobium oxide chains of corner-sharing NbO6 octahedra being further interconnected by selenite anions via Nb-O-Se bridges. The polar compound 2 features a 1D [NbO(SeO3)2](-) anionic chain in which two neighboring Nb(5+) cations are bridged by one oxo and two selenite anions. The alignments of the polarizations from the NbO6 octahedra in 2 led to a strong SHG response of ∼7.8 × KDP (∼360 × α-SiO2), which is the largest among all phases found in metal-Nb(5+)-Se(4+)/metal-Nb(5+)-Te(4+)-O systems. Furthermore, the material is also type I phase matchable. The above experimental results are consistent with those based on DFT theoretical calculations. Thermal stabilities and optical properties for both compounds are also reported. PMID:26513233

  18. Thermal decomposition of complex halides of arsenic(3), antimony(3) and bismuth(3) with alkali metals

    Energy Technology Data Exchange (ETDEWEB)

    Cyganski, A.; Ptaszynski, B.; Zalewicz, M. (Politechnika Lodzka (Poland))

    1980-01-01

    Thermal analyses of complexes M/sub 3/(As/sub 2/X/sub 9/) (M = Rb, Cs; X = Cl, Br), M/sub 3/(Sb/sub 2/X/sub 9/) (M = Rb, Cs; X = Cl, Br, I), Rb/sub 3/(BiX/sub 6/) (X = Cl, Br) and Cs/sub 3/(Bi/sub 2/X/sub 9/) (X = Cl, Br, I) were performed. From chemical and X-ray analyses of their solid decomposition products the mechanism of thermal decomposition reactions was established. From thermogravimetric curves apparent activation energies were calculated using Coats-Redfern's and Zsako's methods. Thermal stability of complexes increases distinctly in the following order: As

  19. Alkali metal cation complexation and solvent interactions by robust chromium(III) fluoride complexes

    DEFF Research Database (Denmark)

    Birk, T.; Magnussen, M.J.; Piligkos, Stergios;

    2010-01-01

    Interaction of robust chromium(III) fluoride complexes with sodium or lithium cations in solution lead to hypsochromic spectral shifts of increasing magnitude along the series: trans-[CrF2(py)(4)](+), mer-[CrF3(terpy)], and fac-[CrF3(Me(3)tacn)]. Crystalline products isolated from solution exhibi...

  20. Long-range interactions between polar alkali-metal diatoms in external electric fields

    CERN Document Server

    Lepers, Maxence; Aymar, Mireille; Bouloufa-Maafa, Nadia; Dulieu, Olivier

    2013-01-01

    We computed the long-range interactions between two identical polar bialkali molecules in their rovibronic ground level, for all ten species, using accurate quantum chemistry results combined with available spectroscopic data. Huge van der Waals interaction is found for eight species in the free space. The competition of the van der Waals interaction with the dipole-dipole interaction induced by an electric field parallel or perpendicular to the intermolecular axis is described as functions of the electric field magnitude and intermolecular distance. Our calculations predict a regime with a mutual orientation of the two molecules but with no preferential direction in the lab frame. A mechanism for the one-photon assisted association of a pair of ultracold polar molecules into ultracold tetramers is proposed, which would open the way towards the optical manipulation of ultracold polyatomic molecules.

  1. Source processes for the alkali metals in the atmosphere of Mercury

    Science.gov (United States)

    Shemansky, D. E.; Morgan, T. H.

    1991-01-01

    A large (fivefold) increase in Mercury's potassium (K) column abundance on October 14, 1987, has been reported by Sprague et al. (1990), who attributed the enhancement to diffusion through the surface in the Caloris Basin, from depths of order 10 km. The postulated source rate is much larger than any previously estimated diffusion rate, and, if true, certainly affects consideration of the origin of other atmospheric species. However, Killen et al. (1991) have pointed out that the claim is not supported by the published observations of K or sodium as a whole. Sprague et al. (1991) have responded by further hypothesizing the existence of several other sources of gas diffusing out of the regolith, all of which are time variable. In any case, the Sprague et al. data indicate large variations in abundance, and it is important to understand the cause. With this issue in mind, the available abundance estimates for correlation with possible controlling physical parameters has ben examined. A significant correlation between the average zenith K column abundance and indices of solar activity has been found.

  2. CO{sub 2} absorption and regeneration of alkali metal-based solid sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Soo Chool; Choi, Bo Yun; Kim, Jae Chang [Department of Chemical Engineering, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Lee, Tae Jin [Department of Chemical Engineering, Yeungnam University, Kyongsan 712-749 (Korea, Republic of); Ryu, Chong Kul [Korea Electric Power Research Institute, Daejon 305-380 (Korea, Republic of); Ahn, Young Soo [Korea Institute of Energy Research, Daejeon 305-343 (Korea, Republic of)

    2006-02-15

    Potassium-based sorbents were prepared by impregnation with potassium carbonate on supports such as activated carbon (AC), TiO{sub 2}, Al{sub 2}O{sub 3}, MgO, SiO{sub 2} and various zeolites. The CO{sub 2} capture capacity and regeneration property were measured in the presence of H{sub 2}O in a fixed-bed reactor, during multiple cycles at various temperature conditions (CO{sub 2} capture at 60{sup o}C and regeneration at 130-400{sup o}C). Sorbents such as K{sub 2}CO{sub 3}/AC, K{sub 2}CO{sub 3}/TiO{sub 2}, K{sub 2}CO{sub 3}/MgO, and K{sub 2}CO{sub 3}/Al{sub 2}O{sub 3}, which showed excellent CO{sub 2} capture capacity, could be completely regenerated above 130, 130, 350, and 400{sup o}C, respectively. The decrease in the CO{sub 2} capture capacity of K{sub 2}CO{sub 3}/Al{sub 2}O{sub 3} and K{sub 2}CO{sub 3}/MgO, after regeneration at temperatures of less than 200{sup o}C, could be explained through the formation of KAl(CO{sub 3}){sub 2}(OH){sub 2}, K{sub 2}Mg(CO{sub 3}){sub 2}, and K{sub 2}Mg(CO{sub 3}){sub 2}.4(H{sub 2}O), which did not completely converted to the original K{sub 2}CO{sub 3} phase. In the case of K{sub 2}CO{sub 3}/AC and K{sub 2}CO{sub 3}/TiO{sub 2}, a KHCO{sub 3} crystal structure was formed during CO{sub 2} absorption, unlike K{sub 2}CO{sub 3}/Al{sub 2}O{sub 3} and K{sub 2}CO{sub 3}/MgO. This phase could be easily converted into the original phase during regeneration, even at a low temperature (130{sup o}C). Therefore, the formation of the KHCO{sub 3} crystal structure after CO{sub 2} absorption is an important factor for regeneration, even at the low temperature. The nature of support plays an important role for CO{sub 2} absorption and regeneration capacities. In particular, the K{sub 2}CO{sub 3}/TiO{sub 2} sorbent showed excellent characteristics in CO{sub 2} absorption and regeneration in that it satisfies the requirements of a large amount of CO{sub 2} absorption (mgCO{sub 2}/gsorbent) and fast and complete regeneration at a low temperature condition (1 atm, 150{sup o}C). (author)

  3. X-ray and neutron diffraction studies of some liquid alkali metals and alloys

    International Nuclear Information System (INIS)

    Experimental techniques and correction procedures have been searched for, which allow a reliable and accurate determination of the structure factors of simple liquid metals, particularly in the small-angle region. A study of binary alloys was carried out and showed that clustering of like atoms (a tendency to phase separation) occurs, indicating special structural aspects. The densities of Na-K, Na-Cs, K-Rb alloys were also measured. (C.F.)

  4. Plasma assisted measurements of alkali metal concentrations in pressurised combustion processes

    Energy Technology Data Exchange (ETDEWEB)

    Hernberg, R.; Haeyrinen, V. [Tampere Univ. of Technology (Finland)

    1997-10-01

    In this project the continuous alkali measurement method plasma excited alkali resonance line spectroscopy (PEARLS) was developed, tested and demonstrated in pressurised combustion facilities. The PEARLS method has been developed at Tampere University of Technology (TUT). During 1994-1996 the PEARLS method was developed from the laboratory level to an industrial prototype. The alkali measuring instrument has been tested and used for regular measurements in four different pressurised combustion installations ranging up to industrial pilot scale. The installations are: (1) a pressurised entrained flow reactor (PEFR) at VTT Energy in Jyvaeskylae, Finland (2) a pressurised fluidised bed combustion facility, called FRED, at DMT in Essen, Germany. (3) a 10 MW pressurised circulating fluidised bed combustion pilot plant at Foster Wheeler Energia Oy in Karhula, Finland (4) PFBC Research Facility at ABB Carbon in Finspaang, Sweden

  5. Atomic many-body effects and Lamb shifts in alkali metals

    CERN Document Server

    Ginges, J S M

    2016-01-01

    We present a detailed study of the Flambaum-Ginges radiative potential method which enables the accurate inclusion of quantum electrodynamics (QED) radiative corrections in a simple manner in atoms, ions, and molecules over the range 10<=Z<=120, where Z is the nuclear charge. Calculations are performed for binding energy shifts to the lowest valence s, p, and d waves over the series of alkali atoms Na to E119. The high accuracy of the radiative potential method is demonstrated by comparison with rigorous QED calculations in frozen atomic potentials, with deviations on the level of 1%. The many-body effects of core relaxation and second- and higher-order perturbation theory on the interaction of the valence electron with the core are calculated. The inclusion of many-body effects tends to increase the size of the shifts, with the enhancement particularly significant for d waves; for K to E119, the self-energy shifts for d waves are only an order of magnitude smaller than the s-wave shifts. It is shown th...

  6. Poetry and Alkali Metals: Building Bridges to the Study of Atomic Radius and Ionization Energy

    Science.gov (United States)

    Araujo, J. L.; Morais, C.; Paiva, J. C.

    2015-01-01

    Exploring chemistry through its presence in the literature in general, and poetry in particular, may increase students' curiosity, may enhance several basic skills, such as writing, reading comprehension and argumentative skills, as well as may improve the understanding of the chemistry topics covered. Nevertheless, the pedagogical potential of…

  7. Study of solid-phase interaction of antimony and bismuth trifluorides with alkali metal fluorides

    International Nuclear Information System (INIS)

    Methods of X-ray phase, differential thermal and chemical analyses have been used to study and plot phase diagrams of RbF-SbF3, CSF-SbF3, RbF-BjF,L3, CSF-BjF3 systems. X-ray diffraction study on the phases formed in the systems is conducted temperatures of phase transitions are determined, General regularities displayed in M'F-MF3 systems (M'=Li, Na, K, Rb, Cs, M=Sb, Bi) are discussed

  8. Complexing of antimony(3) fluoride with rare alkali metal fluorides in formic acid

    International Nuclear Information System (INIS)

    Using the method of isothermal solubility with the establishment of solid phase compositions according to ''residue method'' the systems HCOOH-SbF3-RbF3 and HCOOH-SbF3-CsF are studied at 15 deg C. The existence of complex compounds of different compositions is established. The individual character of the compounds prepared is confirmed by the data of chemical and X-ray phase analysis

  9. Inelastic neutron scattering spectra of alkali metal (Na, K) bifluorides: The harmonic overtone of v3

    Science.gov (United States)

    Waddington, Thomas C.; Howard, Joseph; Brierley (in part), Keith P.; Tomkinson, John

    1982-01-01

    Inelastic neutron scattering spectra of MFHF (M  Na and K) have been measured up to energy transfers of ca. 4000 cm -1 Both 0 → 1 and 0 → 2 transitions of the bending ( v2), and antisymmetric stretching ( v3) modes were observed. A normal harmonic (i.e. no quartic contribution) model for the dynamics of the bifluoride ion is entirely consistent with our observations. Evidence of phonon dispersion was observed in the band shape of v3, but no structure attributable to the LO mode could be found. The similarity of the band shapes of v3 for both NaFHF and KFHF is interpreted in terms of a very short range coupling mechanism.

  10. New Alkali Metal Flow Battery for Terrestrial and Aerospace Energy Storage Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Renewable energy sources, including wind and solar, can supply a significant amount of electrical energy globally, but their potential has not been fully exploited...

  11. Basis set convergence on static electric dipole polarizability calculations of alkali-metal clusters

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Fabio A. L. de; Jorge, Francisco E., E-mail: jorge@cce.ufes.br [Departamento de Fisica, Universidade Federal do Espirito Santo, 29060-900 Vitoria-ES (Brazil)

    2013-07-15

    A hierarchical sequence of all-electron segmented contracted basis sets of double, triple and quadruple zeta valence qualities plus polarization functions augmented with diffuse functions for the atoms from H to Ar was constructed. A systematic study of basis sets required to obtain reliable and accurate values of static dipole polarizabilities of lithium and sodium clusters (n = 2, 4, 6 and 8) at their optimized equilibrium geometries is reported. Three methods are examined: Hartree-Fock (HF), second-order Moeller-Plesset perturbation theory (MP2), and density functional theory (DFT). By direct calculations or by fitting the directly calculated values through one extrapolation scheme, estimates of the HF, MP2 and DFT complete basis set limits were obtained. Comparison with experimental and theoretical data reported previously in the literature is done (author)

  12. Conditions for preparation of ultrapure beryllium by electrolytic refining in molten alkali-metal chlorides

    Energy Technology Data Exchange (ETDEWEB)

    Wohlfarth, Hagen

    1982-02-01

    Electrolytic refining is regarded as the most suitable process for the production of beryllium with impurity contents below 1 at.-ppM. Several parameters are important for electrolytic refining of beryllium in a BeCl/sub 2/-containing LiCl-KCl melt: current density, BeCl/sub 2/ content, electrolyte temperature, composition of the unpurified beryllium and impurity-ion concentrations in the melt, as well as apparatus characteristics such as rotation speed of the cathode and condition of the crucible material. These factors were studied and optimized such that extensive removal of the maximum number of accompanying and alloying elements was achieved.

  13. Alkali metal – yttrium borohydrides: The link between coordination of small and large rare-earth

    International Nuclear Information System (INIS)

    The system Li–A–Y–BH4 (A=K, Rb, Cs) is found to contain five new compounds and four further ones known from previous work on the homoleptic borohydrides. Crystal structures have been solved and refined from synchrotron X-ray powder diffraction, thermal stability of new compounds have been investigated and ionic conductivity measured for selected samples. Significant coordination flexibility for Y3+ is revealed, which allows the formation of both octahedral frameworks and tetrahedral complex anions with the tetrahydroborate anion BH4 both as a linker and terminal ligand. Bi- and trimetallic cubic double-perovskites c-A3Y(BH4)6 or c-A2LiY(BH4)6 (A=Rb, Cs) form in all the investigated systems, with the exception of the Li–K–Y system. The compounds with the stoichiometry AY(BH4)4 crystallize in all investigated systems with a great variety of structure types which find their analog amongst metal oxides. In-situ formation of a new borohydride – closo-borane is observed during decomposition of all double perovskites. - Graphical abstract: The system Li–A–Y–BH4 (A=K, Rb, Cs) is found to contain five novel compounds and four further ones previously reported. Significant coordination flexibility of Y3+ is revealed, which can be employed to form both octahedral frameworks and tetrahedral complex anions, very different structural topologies. Versatility is also manifested in three different simultaneously occurring coordination modes of borohydrides for one metal cation, as proposed by DFT optimization of the monoclinic KY(BH4)4 structural model observed by powder diffraction. - Highlights: • The system Li-A-Y-BH4 (A=K, Rb, Cs) contains nine compounds in total. • Y3+ forms octahedral frameworks and tetrahedral complex anions. • Bi- and trimetallic double-perovskites crystallize in most systems. • Various AY(BH4)4 crystallize with structure types analogous to metal oxides. • Double-perovskites decompose and form a novel borohydride-closo-borane

  14. Superconductivity and electrical resistivity in alkali metal doped fullerides: Phonon mechanism

    Indian Academy of Sciences (India)

    Dinesh Varshney; A Dube; K K Choudhary; R K Singh

    2005-04-01

    We consider a two-peak model for the phonon density of states to investigate the nature of electron pairing mechanism for superconducting state in fullerides. We first study the intercage interactions between the adjacent C60 cages and expansion of lattice due to the intercalation of alkali atoms based on the spring model to estimate phonon frequencies from the dynamical matrix for the intermolecular alkali-C60 phonons. Electronic parameter as repulsive parameter and the attractive coupling strength are obtained within the random phase approximation. Transition temperature, c, is obtained in a situation when the free electrons in lowest molecular orbital are coupled with alkali-C60 phonons as 5 K, which is much lower as compared to reported c (≈ 20 K). The superconducting pairing is mainly driven by the high frequency intramolecular phonons and their effects enhance it to 22 K. To illustrate the usefulness of the above approach, the carbon isotope exponent and the pressure effect are also estimated. Temperature dependence of electrical resistivity is then analysed within the same model phonon spectrum. It is inferred from the two-peak model for phonon density of states that high frequency intramolecular phonon modes play a major role in pairing mechanism with possibly some contribution from alkali-C60 phonon to describe most of the superconducting and normal state properties of doped fullerides.

  15. Long-range interactions between the alkali-metal atoms and alkaline earth ions

    CERN Document Server

    Kaur, Jasmeet; Arora, Bindiya; Sahoo, B K

    2014-01-01

    Accurate knowledge of interaction potentials among the alkali atoms and alkaline earth ions is very useful in the studies of cold atom physics. Here we carry out theoretical studies of the long-range interactions among the Li, Na, K, and Rb alkali atoms with the Ca$^+$, Ba$^+$, Sr$^+$, and Ra$^+$ alkaline earth ions systematically which are largely motivated by their importance in a number of applications. These interactions are expressed as a power series in the inverse of the internuclear separation $R$. Both the dispersion and induction components of these interactions are determined accurately from the algebraic coefficients corresponding to each power combination in the series. Ultimately, these coefficients are expressed in terms of the electric multipole polarizabilities of the above mentioned systems which are calculated using the matrix elements obtained from a relativistic coupled-cluster method and core contributions to these quantities from the random phase approximation. We also compare our estim...

  16. Accurate studies of dissociation energies and vibrational energies on alkali metals

    Institute of Scientific and Technical Information of China (English)

    Liu Xiu-Ying; Sun Wei-Guo; Fan Qun-Chao

    2008-01-01

    This paper studies full vibrational spectra {Ev} and molecular dissociation energies De by using conventional least-squares (LS) fitting and an algebraic method (AM) proposed recently for 10 diatomic electronic states of 7Li2, Na2, NaK and NaLi molecules based on some known experimental vibrational energies in a subset [Eexptv] respectively. Studies show that: (1) although both the full AM spectrum {EAMv} and the LS spectrum {ELSv} can reproduce the known experimental energies in [Eexptv], the {EAMv} is superior to the {Els} in that the high-lying AM vibrational energies which may not be available experimentally have better or much better accuracy than those LS counterparts in {ELSv}, and so is the AM dissociation energy DAMe; (2) the main source of the errors in the data obtained by using the LS fitting is that the fitting which is just a pure mathematical process does not use any physical criteria that must be satisfied by the full vibrational spectrum, while the AM method does. This study suggests that when fitting or solving a physical equation using a set of source data, it is important not only to apply a proper mathematical tool, but also to use correct physical criteria which measure the physical properties of the data, kick out those data having bigger errors, and impose conditional convergence on the numerical process.

  17. Optimized random phase approximation for the structure of liquid alkali metals as electron-ion plasmas

    International Nuclear Information System (INIS)

    The purpose of this letter is to stress that the way towards an unconventional optimized-random-phase-approximation (ORPA) approach to the structure of liquid metals is indicated, and in fact already a good first-order solution for such an approach is provided

  18. Solubility of alkali metal halides in the ionic liquid [C4C1im][OTf].

    Science.gov (United States)

    Kuzmina, O; Bordes, E; Schmauck, J; Hunt, P A; Hallett, J P; Welton, T

    2016-06-28

    The solubilities of the metal halides LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KI, RbCl, CsCl, CsI, were measured at temperatures ranging from 298.15 to 378.15 K in the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([C4C1im][OTf]). Li(+), Na(+) and K(+) salts with anions matching the ionic liquid have also been investigated to determine how well these cations dissolve in [C4C1im][OTf]. This study compares the influence of metal cation and halide anion on the solubility of salts within this ionic liquid. The highest solubility found was for iodide salts, and the lowest solubility for the three fluoride salts. There is no outstanding difference in the solubility of salts with matching anions in comparison to halide salts. The experimental data were correlated employing several phase equilibria models, including ideal mixtures, van't Hoff, the λh (Buchowski) equation, the modified Apelblat equation, and the non-random two-liquid model (NRTL). It was found that the van't Hoff model gave the best correlation results. On the basis of the experimental data the thermodynamic dissolution parameters (ΔH, ΔS, and ΔG) were determined for the studied systems together with computed gas phase metathesis parameters. Dissolution depends on the energy difference between enthalpies of fusion and dissolution of the solute salt. This demonstrates that overcoming the lattice energy of the solid matrix is the key to the solubility of inorganic salts in ionic liquids. PMID:27264676

  19. Alkali metal and ammonium chlorides in water and heavy water (binary systems)

    CERN Document Server

    Cohen-Adad, R

    1991-01-01

    This volume surveys the data available in the literature for solid-fluid solubility equilibria plus selected solid-liquid-vapour equilibria, for binary systems containing alkali and ammonium chlorides in water or heavy water. Solubilities covered are lithium chloride, sodium chloride, potassium chloride, rubidium chloride, caesium chloride and ammonium chloride in water and heavy water.

  20. Plasma assisted measurements of alkali metal concentrations in pressurized combustion processes

    Energy Technology Data Exchange (ETDEWEB)

    Hernberg, R.; Haeyrinen, V. [Tampere Univ. of Technology (Finland). Dept. of Physics

    1996-12-01

    The plasma assisted method for continuous measurement of alkali concentrations in product gas flows of pressurized energy processes will be tested and applied at the 1.6 MW PFBC/G facility at Delft University of Technology in the Netherlands. During the reporting period the alkali measuring device has been tested under pressurized conditions at VTT Energy, DMT, Foster-Wheeler Energia and ABB Carbon. Measurements in Delft will be performed during 1996 after installation of the hot gas filter. The original plan for measurements in Delft has been postponed due to schedule delays in Delft. The results are expected to give information about the influence of different process conditions on the generation of alkali vapours, the comparison of different methods for alkali measurement and the specific performance of our system. This will be the first test of the plasma assisted measurement method in a gasification process. The project belongs to the Joule II extension program under contract JOU2-CT93-0431. (author)