Sample records for atomic absorption apparatus

  1. An induction furnace for the determination of cadmium in solutions and zinc-base metals by atomic-absorption spectroscopy.

    PubMed

    Headridge, J B; Smith, D R

    1971-03-01

    An induction furnace coupled to a Unicam SP90 atomic-absorption spectrophotometer is described for the determination of traces of volatile elements in solutions and volatile matrices. The apparatus has been used to obtain calibration graphs for 1-20 and 50-750 ng of cadmium in microl-volumes of solution, the 228.8 and 326.2 nm resonance lines respectively being used, and to determine cadmium in 5-mg samples of zinc-base metals within the concentration range 5-400 microg g by using the less sensitive 326-2-nm line. A furnace temperature of 1,350 degrees was used. Data on accuracy and precision are presented. The apparatus could readily be used to determine trace elements in volatile materials at concentrations of 10-1000 ng/g .

  2. [Application of atomic absorption spectrometry in the engine knock detection].

    PubMed

    Chen, Li-Dan

    2013-02-01

    Because existing human experience diagnosis method and apparatus for auxiliary diagnosis method are difficult to diagnose quickly engine knock. Atomic absorption spectrometry was used to detect the automobile engine knock in in innovative way. After having determined Fe, Al, Cu, Cr and Pb content in the 35 groups of Audi A6 engine oil whose travel course is 2 000 -70 000 kilometers and whose sampling interval is 2 000 kilometers by atomic absorption spectrometry, the database of primary metal content in the same automobile engine at different mileage was established. The research shows that the main metal content fluctuates within a certain range. In practical engineering applications, after the determination of engine oil main metal content and comparison with its database value, it can not only help to diagnose the type and location of engine knock without the disintegration and reduce vehicle maintenance costs and improve the accuracy of engine knock fault diagnosis.

  3. Precision atomic beam density characterization by diode laser absorption spectroscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Oxley, Paul; Wihbey, Joseph

    2016-09-15

    We provide experimental and theoretical details of a simple technique to determine absolute line-of-sight integrated atomic beam densities based on resonant laser absorption. In our experiments, a thermal lithium beam is chopped on and off while the frequency of a laser crossing the beam at right angles is scanned slowly across the resonance transition. A lock-in amplifier detects the laser absorption signal at the chop frequency from which the atomic density is determined. The accuracy of our experimental method is confirmed using the related technique of wavelength modulation spectroscopy. For beams which absorb of order 1% of the incident lasermore » light, our measurements allow the beam density to be determined to an accuracy better than 5% and with a precision of 3% on a time scale of order 1 s. Fractional absorptions of order 10{sup −5} are detectable on a one-minute time scale when we employ a double laser beam technique which limits laser intensity noise. For a lithium beam with a thickness of 9 mm, we have measured atomic densities as low as 5 × 10{sup 4} atoms cm{sup −3}. The simplicity of our technique and the details we provide should allow our method to be easily implemented in most atomic or molecular beam apparatuses.« less

  4. Precision atomic beam density characterization by diode laser absorption spectroscopy.

    PubMed

    Oxley, Paul; Wihbey, Joseph

    2016-09-01

    We provide experimental and theoretical details of a simple technique to determine absolute line-of-sight integrated atomic beam densities based on resonant laser absorption. In our experiments, a thermal lithium beam is chopped on and off while the frequency of a laser crossing the beam at right angles is scanned slowly across the resonance transition. A lock-in amplifier detects the laser absorption signal at the chop frequency from which the atomic density is determined. The accuracy of our experimental method is confirmed using the related technique of wavelength modulation spectroscopy. For beams which absorb of order 1% of the incident laser light, our measurements allow the beam density to be determined to an accuracy better than 5% and with a precision of 3% on a time scale of order 1 s. Fractional absorptions of order 10 -5 are detectable on a one-minute time scale when we employ a double laser beam technique which limits laser intensity noise. For a lithium beam with a thickness of 9 mm, we have measured atomic densities as low as 5 × 10 4 atoms cm -3 . The simplicity of our technique and the details we provide should allow our method to be easily implemented in most atomic or molecular beam apparatuses.

  5. Hybrid isotope separation scheme

    DOEpatents

    Maya, Jakob

    1991-01-01

    A method of yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which a scavenger, radiating the gas with a wave length or frequency characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photochemical reaction between the scavenger, and collecting the specific isotope-containing chemical by using a recombination surface or by a scooping apparatus.

  6. Novel hybrid isotope separation scheme and apparatus

    DOEpatents

    Maya, Jakob

    1991-01-01

    A method of yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which the specific isotope is to be isolated, radiating the gas with frequencies characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photoionization reaction of the desired isotope, and collecting the specific isotope ion by suitable ion collection means.

  7. Electromagnetically Induced Absorption (EIA) and a ``Twist'' on Nonlinear Magneto-optical Rotation (NMOR) with Cold Atoms

    NASA Astrophysics Data System (ADS)

    Kunz, Paul; Meyer, David; Quraishi, Qudsia

    2015-05-01

    Within the class of nonlinear optical effects that exhibit sub-natural linewidth features, electromagnetically induced transparency (EIT) and nonlinear magneto-optical rotation (NMOR) stand out as having made dramatic impacts on various applications including atomic clocks, magnetometry, and single photon storage. A related effect, known as electromagnetically induced absorption (EIA), has received less attention in the literature. Here, we report on the first observation of EIA in cold atoms using the Hanle configuration, where a single laser beam is used to both pump and probe the atoms while sweeping a magnetic field through zero along the beam direction. We find that, associated with the EIA peak, a ``twist'' appears in the corresponding NMOR signal. A similar twist has been previously noted by Budker et al., in the context of warm vapor optical magnetometry, and was ascribed to optical pumping through nearby hyperfine levels. By studying this feature through numerical simulations and cold atom experiments, thus rendering the hyperfine levels well resolved, we enhance the understanding of the optical pumping mechanism behind it, and elucidate its relation to EIA. Finally, we demonstrate a useful application of these studies through a simple and rapid method for nulling background magnetic fields within our atom chip apparatus.

  8. Automation of preparation of nonmetallic samples for analysis by atomic absorption and inductively coupled plasma spectrometry

    NASA Technical Reports Server (NTRS)

    Wittmann, A.; Willay, G.

    1986-01-01

    For a rapid preparation of solutions intended for analysis by inductively coupled plasma emission spectrometry or atomic absorption spectrometry, an automatic device called Plasmasol was developed. This apparatus used the property of nonwettability of glassy C to fuse the sample in an appropriate flux. The sample-flux mixture is placed in a composite crucible, then heated at high temperature, swirled until full dissolution is achieved, and then poured into a water-filled beaker. After acid addition, dissolution of the melt, and filling to the mark, the solution is ready for analysis. The analytical results obtained, either for oxide samples or for prereduced iron ores show that the solutions prepared with this device are undistinguished from those obtained by manual dissolutions done by acid digestion or by high temperature fusion. Preparation reproducibility and analytical tests illustrate the performance of Plasmasol.

  9. Novel hybrid isotope separation scheme and apparatus

    DOEpatents

    Maya, J.

    1991-06-18

    A method is described for yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which the specific isotope is to be isolated, radiating the gas with frequencies characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photoionization reaction of the desired isotope, and collecting the specific isotope ion by suitable ion collection means. 3 figures.

  10. Hybrid isotope separation scheme

    DOEpatents

    Maya, J.

    1991-06-18

    A method is described for yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which a scavenger, radiating the gas with a wave length or frequency characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photochemical reaction between the scavenger, and collecting the specific isotope-containing chemical by using a recombination surface or by a scooping apparatus. 2 figures.

  11. Method and apparatus for producing laser radiation following two-photon excitation of a gaseous medium

    DOEpatents

    Bischel, William K. [Menlo Park, CA; Jacobs, Ralph R. [Livermore, CA; Prosnitz, Donald [Hamden, CT; Rhodes, Charles K. [Palo Alto, CA; Kelly, Patrick J. [Fort Lewis, WA

    1979-02-20

    Method and apparatus for producing laser radiation by two-photon optical pumping of an atomic or molecular gaseous medium and subsequent lasing action. A population inversion is created as a result of two-photon absorption of the gaseous species. Stark tuning is utilized, if necessary, in order to tune the two-photon transition into exact resonance. In particular, gaseous ammonia (NH.sub.3) or methyl fluoride (CH.sub.3 F) is optically pumped by a pair of CO.sub.2 lasers to create a population inversion resulting from simultaneous two-photon excitation of a high-lying vibrational state, and laser radiation is produced by stimulated emission of coherent radiation from the inverted level.

  12. Method and apparatus for producing laser radiation following two-photon excitation of a gaseous medium

    DOEpatents

    Bischel, W.K.; Jacobs, R.R.; Prosnitz, D.P.; Rhodes, C.K.; Kelly, P.J.

    1979-02-20

    Method and apparatus are disclosed for producing laser radiation by two-photon optical pumping of an atomic or molecular gaseous medium and subsequent lasing action. A population inversion is created as a result of two-photon absorption of the gaseous species. Stark tuning is utilized, if necessary, in order to tune the two-photon transition into exact resonance. In particular, gaseous ammonia (NH[sub 3]) or methyl fluoride (CH[sub 3]F) is optically pumped by a pair of CO[sub 2] lasers to create a population inversion resulting from simultaneous two-photon excitation of a high-lying vibrational state, and laser radiation is produced by stimulated emission of coherent radiation from the inverted level. 3 figs.

  13. Optical signatures of molecular particles via mass-selected cluster spectroscopy

    NASA Technical Reports Server (NTRS)

    Duncan, Michael A.

    1990-01-01

    A new molecular beam apparatus was developed to study optical absorption in cold (less than 100 K) atomic clusters and complexes produced by their condensation with simple molecular gases. In this instrument, ionized clusters produced in a laser vaporization nozzle source are mass selected and studied with photodissociation spectroscopy at visible and ultraviolet wavelengths. This new approach can be applied to synthesize and characterize numerous particulates and weakly bound complexes expected in planetary atmospheres and in comets.

  14. Multivessel system for cold-vapor mercury generation. Determination of mercury in hair and fish.

    PubMed

    Boaventura, G R; Barbosa, A C; East, G A

    1997-01-01

    A multivessel system for the determination of mercury (Hg) by cold-vapor atomic absorption spectrometry (CV-AAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) was developed. The performance of the proposed device was tested by determining total Hg in quality-control samples of hair and fishes following acid digestion. Application of the apparatus to the determination of Hg by CV-AAS following alkaline digestion was studied as well. The detection limit obtained for CV-AAS was 0.11 ng/mL and for ICP-AES 1.39 ng/mL. The results show that the system is appropriate to be used in techniques involving cold-vapor generation of Hg.

  15. Atom chip apparatus for experiments with ultracold rubidium and potassium gases

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ivory, M. K.; Ziltz, A. R.; Fancher, C. T.

    2014-04-15

    We present a dual chamber atom chip apparatus for generating ultracold {sup 87}Rb and {sup 39}K atomic gases. The apparatus produces quasi-pure Bose-Einstein condensates of 10{sup 4} {sup 87}Rb atoms in an atom chip trap that features a dimple and good optical access. We have also demonstrated production of ultracold {sup 39}K and subsequent loading into the chip trap. We describe the details of the dual chamber vacuum system, the cooling lasers, the magnetic trap, the multicoil magnetic transport system, the atom chip, and two optical dipole traps. Due in part to the use of light-induced atom desorption, the lasermore » cooling chamber features a sufficiently good vacuum to also support optical dipole trap-based experiments. The apparatus is well suited for studies of atom-surface forces, quantum pumping and transport experiments, atom interferometry, novel chip-based traps, and studies of one-dimensional many-body systems.« less

  16. Atomic oxygen reactor having at least one sidearm conduit

    NASA Technical Reports Server (NTRS)

    Koontz, Steven L. (Inventor)

    1994-01-01

    An apparatus for treating a microporous structure with atomic oxygen is presented. The apparatus includes a main gas chamber for flowing gas in an axial direction and a source of gas, containing atomic oxygen, connected for introducing the gas into the main gas chamber. The apparatus employs at least one side arm extending from the main atomic oxygen-containing chamber. The side arm has characteristic relaxation times such that a uniform atomic oxygen dose rate is delivered to a specimen positioned transversely in the side arm spaced from the main gas chamber.

  17. Development of optical coatings for 157-nm lithography. II. Reflectance, absorption, and scatter measurement

    NASA Astrophysics Data System (ADS)

    Otani, Minoru; Biro, Ryuji; Ouchi, Chidane; Hasegawa, Masanobu; Suzuki, Yasuyuki; Sone, Kazuho; Niisaka, Shunsuke; Saito, Tadahiko; Saito, Jun; Tanaka, Akira

    2002-06-01

    The total loss that can be suffered by an antireflection (AR) coating consists of reflectance loss, absorption loss, and scatter loss. To separate these losses we developed a calorimetric absorption measurement apparatus and an ellipsoidal Coblentz hemisphere based scatterometer for 157-nm optics. Reflectance, absorption, and scatter of AR coatings were measured with these apparatuses. The AR coating samples were supplied by Japanese vendors. Each AR coating as supplied was coated with the vendor's coating design by that vendor's coating process. Our measurement apparatuses, methods, and results for these AR coatings are presented here.

  18. H2/O2 three-body rates at high temperatures

    NASA Technical Reports Server (NTRS)

    Marinelli, William J.; Kessler, William J.; Piper, Lawrence G.; Rawlins, W. Terry

    1990-01-01

    The extraction of thrust from air breathing hypersonic propulsion systems is critically dependent on the degree to which chemical equilibrium is reached in the combustion process. In the combustion of H2/Air mixtures, slow three-body chemical reactions involving H-atoms, O-atoms, and the OH radical play an important role in energy extraction. A first-generation high temperature and pressure flash-photolysis/laser-induced fluorescence reactor was designed and constructed to measure these important three-body rates. The system employs a high power excimer laser to produce these radicals via the photolysis of stable precursors. A novel two-photon laser-induced fluorescence technique is employed to detect H-atoms without optical thickness or O2 absorption problems. To demonstrate the feasibility of the technique the apparatus in the program is designed to perform preliminary measurements on the H + O2 + M reaction at temperatures from 300 to 835 K.

  19. Polarized internal target apparatus

    DOEpatents

    Holt, Roy J.

    1986-01-01

    A polarized internal target apparatus with a polarized gas target of improved polarization and density achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms.

  20. An apparatus for immersing trapped ions into an ultracold gas of neutral atoms

    NASA Astrophysics Data System (ADS)

    Schmid, Stefan; Härter, Arne; Frisch, Albert; Hoinka, Sascha; Denschlag, Johannes Hecker

    2012-05-01

    We describe a hybrid vacuum system in which a single ion or a well-defined small number of trapped ions (in our case Ba+ or Rb+) can be immersed into a cloud of ultracold neutral atoms (in our case Rb). This apparatus allows for the study of collisions and interactions between atoms and ions in the ultracold regime. Our setup is a combination of a Bose-Einstein condensation apparatus and a linear Paul trap. The main design feature of the apparatus is to first separate the production locations for the ion and the ultracold atoms and then to bring the two species together. This scheme has advantages in terms of stability and available access to the region where the atom-ion collision experiments are carried out. The ion and the atoms are brought together using a moving one-dimensional optical lattice transport which vertically lifts the atomic sample over a distance of 30 cm from its production chamber into the center of the Paul trap in another chamber. We present techniques to detect and control the relative position between the ion and the atom cloud.

  1. A Next-Generation Apparatus for Lithium Optical Lattice Experiments

    NASA Astrophysics Data System (ADS)

    Keshet, Aviv

    Quantum simulation is emerging as an ambitious and active subfield of atomic physics. This thesis describes progress towards the goal of simulating condensed matter systems, in particular the physics of the Fermi-Hubbard model, using ultracold Lithium atoms in an optical lattice. A major goal of the quantum simulation program is to observe phase transitions of the Hubbard model, into Neal antiferromagnetic phases and d-wave superfluid phases. Phase transitions are generally accompanied by a change in an underlying correlation in a physical system. Such correlations may be most amenable to probing by looking at fluctuations in the system. Experimental techniques for probing density and magnetization fluctuations in a variety of atomic Fermi systems are developed. The suppression of density fluctuations (or atom "shot noise") in an ideal degenerate Fermi gas is observed by absorption imaging of time-of-flight expanded clouds. In-trap measurements of density and magnetization fluctuations are not easy to probe with absorption imaging, due to their extremely high attenuation. A method to probe these fluctuations based on speckle patterns, caused by fluctuations in the index of refraction for a detuned illumination beam, is developed and applied first to weakly interacting and then to strongly interacting in-trap gases. Fluctuation probes such as these will be a crucial tool in future quantum simulation of condensed matter systems. The quantum simulation experiments that we want to perform require a complex sequence of precisely timed computer controlled events. A distributed GUI-based control system designed with such experiments in mind, The Cicero Word Generator, is described. The system makes use of a client-server separation between a user interface for sequence design and a set of output hardware servers. Output hardware servers are designed to use standard National Instruments output cards, but the client-server nature allows this to be extended to other output hardware. Output sequences running on multiple servers and output cards can be synchronized using a shared clock. By using an FPGA-generated variable frequency clock, redundant buffers can be dramatically shortened, and a time resolution of 100ns achieved over effectively arbitrary sequence lengths. Experimental set-ups for producing, manipulating, and probing ultracold atomic gases can be quite complicated. To move forward with a quantum simulation program, it is necessary to have an apparatus that operates with a reliability that is not easily achieved in the face of this complexity. The design of a new apparatus is discussed. This Sodium-Lithium ultracold gas production machine has been engineered to incorporate as much experimental experience as possible to enhance its reliability. Particular attention has been paid to maximizing optical access and the utilization of this optical access, controlling the ambient temperature of the experiment, achieving a high vacuum, and simplifying subsystems where possible. The apparatus is now on the verge of producing degenerate gases, and should serve as a stable platform on which to perform future lattice quantum simulation experiments. (Copies available exclusively from MIT Libraries, libraries.mit.edu/docs - docs mit.edu)

  2. Polarized internal target apparatus

    DOEpatents

    Holt, R.J.

    1984-10-10

    A polarized internal target apparatus with a polarized gas target of improved polarization and density (achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms) is described.

  3. In-situ control system for atomization

    DOEpatents

    Anderson, I.E.; Figliola, R.S.; Terpstra, R.L.

    1995-06-13

    Melt atomizing apparatus comprising a melt supply orifice for supplying the melt for atomization and gas supply orifices proximate the melt supply orifice for supplying atomizing gas to atomize the melt as an atomization spray is disclosed. The apparatus includes a sensor, such as an optical and/or audio sensor, for providing atomization spray data, and a control unit responsive to the sensed atomization spray data for controlling at least one of the atomizing gas pressure and an actuator to adjust the relative position of the gas supply orifice and melt supply in a manner to achieve a desired atomization spray. 3 figs.

  4. In-situ control system for atomization

    DOEpatents

    Anderson, Iver E.; Figliola, Richard S.; Terpstra, Robert L.

    1995-06-13

    Melt atomizing apparatus comprising a melt supply orifice for supplying the melt for atomization and gas supply orifices proximate the melt supply orifice for supplying atomizing gas to atomize the melt as an atomization spray. The apparatus includes a sensor, such as an optical and/or audio sensor, for providing atomization spray data, and a control unit responsive to the sensed atomization spray data for controlling at least one of the atomizing gas pressure and an actuator to adjust the relative position of the gas supply orifice and melt supply in a manner to achieve a desired atomization spray.

  5. Cold Atom Source Containing Multiple Magneto-Optical Traps

    NASA Technical Reports Server (NTRS)

    Ramirez-Serrano, Jaime; Kohel, James; Kellogg, James; Lim, Lawrence; Yu, Nan; Maleki, Lute

    2007-01-01

    An apparatus that serves as a source of a cold beam of atoms contains multiple two-dimensional (2D) magneto-optical traps (MOTs). (Cold beams of atoms are used in atomic clocks and in diverse scientific experiments and applications.) The multiple-2D-MOT design of this cold atom source stands in contrast to single-2D-MOT designs of prior cold atom sources of the same type. The advantages afforded by the present design are that this apparatus is smaller than prior designs.

  6. Production and characterization of a dual species magneto-optical trap of cesium and ytterbium.

    PubMed

    Kemp, S L; Butler, K L; Freytag, R; Hopkins, S A; Hinds, E A; Tarbutt, M R; Cornish, S L

    2016-02-01

    We describe an apparatus designed to trap and cool a Yb and Cs mixture. The apparatus consists of a dual species effusive oven source, dual species Zeeman slower, magneto-optical traps in a single ultra-high vacuum science chamber, and the associated laser systems. The dual species Zeeman slower is used to load sequentially the two species into their respective traps. Its design is flexible and may be adapted for other experiments with different mixtures of atomic species. The apparatus provides excellent optical access and can apply large magnetic bias fields to the trapped atoms. The apparatus regularly produces 10(8) Cs atoms at 13.3 μK in an optical molasses, and 10(9) (174)Y b atoms cooled to 22 μK in a narrowband magneto-optical trap.

  7. Matrix isolation sublimation: An apparatus for producing cryogenic beams of atoms and molecules

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sacramento, R. L.; Alves, B. X.; Silva, B. A.

    2015-07-15

    We describe the apparatus to generate cryogenic beams of atoms and molecules based on matrix isolation sublimation. Isolation matrices of Ne and H{sub 2} are hosts for atomic and molecular species which are sublimated into vacuum at cryogenic temperatures. The resulting cryogenic beams are used for high-resolution laser spectroscopy. The technique also aims at loading atomic and molecular traps.

  8. High data rate atom interferometric device

    DOEpatents

    Biedermann, Grant; McGuinness, Hayden James Evans; Rakholia, Akash

    2015-07-21

    A light-pulse atomic interferometry (LPAI) apparatus is provided. The LPAI apparatus comprises a vessel, two sets of magnetic coils configured to magnetically confine an atomic vapor in two respective magneto-optical traps (MOTs) within the vessel when activated, and an optical system configured to irradiate the atomic vapor within the vessel with laser radiation that, when suitably tuned, can launch atoms previously confined in each of the MOTs toward the other MOT. In embodiments, the magnetic coils are configured to produce a magnetic field that is non-zero at the midpoint between the traps. In embodiments, the time-of-flight of the launched atoms from one MOT to the other is 12 ms or less. In embodiments, the MOTs are situated approximately 36 mm apart. In embodiments, the apparatus is configured to activate the magnetic coils according to a particular temporal magnetic field gradient profile.

  9. Calibration method and apparatus for measuring the concentration of components in a fluid

    DOEpatents

    Durham, M.D.; Sagan, F.J.; Burkhardt, M.R.

    1993-12-21

    A calibration method and apparatus for use in measuring the concentrations of components of a fluid is provided. The measurements are determined from the intensity of radiation over a selected range of radiation wavelengths using peak-to-trough calculations. The peak-to-trough calculations are simplified by compensating for radiation absorption by the apparatus. The invention also allows absorption characteristics of an interfering fluid component to be accurately determined and negated thereby facilitating analysis of the fluid. 7 figures.

  10. Calibration method and apparatus for measuring the concentration of components in a fluid

    DOEpatents

    Durham, Michael D.; Sagan, Francis J.; Burkhardt, Mark R.

    1993-01-01

    A calibration method and apparatus for use in measuring the concentrations of components of a fluid is provided. The measurements are determined from the intensity of radiation over a selected range of radiation wavelengths using peak-to-trough calculations. The peak-to-trough calculations are simplified by compensating for radiation absorption by the apparatus. The invention also allows absorption characteristics of an interfering fluid component to be accurately determined and negated thereby facilitating analysis of the fluid.

  11. Method and apparatus for differential spectroscopic atomic-imaging using scanning tunneling microscopy

    DOEpatents

    Kazmerski, Lawrence L.

    1990-01-01

    A Method and apparatus for differential spectroscopic atomic-imaging is disclosed for spatial resolution and imaging for display not only individual atoms on a sample surface, but also bonding and the specific atomic species in such bond. The apparatus includes a scanning tunneling microscope (STM) that is modified to include photon biasing, preferably a tuneable laser, modulating electronic surface biasing for the sample, and temperature biasing, preferably a vibration-free refrigerated sample mounting stage. Computer control and data processing and visual display components are also included. The method includes modulating the electronic bias voltage with and without selected photon wavelengths and frequency biasing under a stabilizing (usually cold) bias temperature to detect bonding and specific atomic species in the bonds as the STM rasters the sample. This data is processed along with atomic spatial topography data obtained from the STM raster scan to create a real-time visual image of the atoms on the sample surface.

  12. Cu determination in crude oil distillation products by atomic absorption and inductively coupled plasma mass spectrometry after analyte transfer to aqueous solution

    NASA Astrophysics Data System (ADS)

    Kowalewska, Zofia; Ruszczyńska, Anna; Bulska, Ewa

    2005-03-01

    Cu was determined in a wide range of petroleum products from crude oil distillation using flame atomic absorption spectrometry (FAAS), electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma mass spectrometry (ICP-MS). Different procedures of sample preparation were evaluated: (i) mineralization with sulfuric acid in an open system, (ii) mineralization in a closed microwave system, (iii) combustion in hydrogen-oxygen flame in the Wickbold's apparatus, (iv) matrix evaporation followed by acid dissolution, and (v) acidic extraction. All the above procedures led to the transfer of the analyte into an aqueous solution for the analytical measurement step. It was found that application of FAAS was limited to the analysis of the heaviest petroleum products of high Cu content. In ICP-MS, the use of internal reference method (with Rh or In as internal reference element) was required to eliminate the matrix effects in the analysis of extracts and the concentrated solutions of mineralized heavy petroleum products. The detection limits (in original samples) were equal to, respectively, 10, 86, 3.3, 0.9 and 0.4 ng g - 1 in procedures i-v with ETAAS detection and 10, 78, 1.1 and 0.5 ng g - 1 in procedures i-iii and v with ICP-MS detection. The procedures recommended here were validated by recovery experiments, certified reference materials analysis and comparison of results, obtained for a given sample, in different ways. The Cu content in the analyzed samples was: 50-110 ng g - 1 in crude oil, < 0.4-6 ng g - 1 in gasoline, < 0.5-2 ng g - 1 in atmospheric oil, < 6-100 ng g - 1 in heavy vacuum oil and 140-300 ng g - 1 in distillation residue.

  13. Apparatus for experimental investigation of aerodynamic radiation with absorption by ablation products

    NASA Technical Reports Server (NTRS)

    Wells, W. L.; Snow, W. L.

    1977-01-01

    A description is given and calibration procedures are presented for an apparatus that is used to simulate aerodynamic radiant heating during planetary entry. The primary function of the apparatus is to simulate the spectral distribution of shock layer radiation and to determine absorption effects of simulated ablation products which are injected into the stagnation region flow field. An electric arc heater is used to heat gas mixtures that represent the planetary atmospheres of interest. Spectral measurements are made with a vacuum ultraviolet scanning monochromator.

  14. Method and apparatus for atomic imaging

    DOEpatents

    Saldin, Dilano K.; de Andres Rodriquez, Pedro L.

    1993-01-01

    A method and apparatus for three dimensional imaging of the atomic environment of disordered adsorbate atoms are disclosed. The method includes detecting and measuring the intensity of a diffuse low energy electron diffraction pattern formed by directing a beam of low energy electrons against the surface of a crystal. Data corresponding to reconstructed amplitudes of a wave form is generated by operating on the intensity data. The data corresponding to the reconstructed amplitudes is capable of being displayed as a three dimensional image of an adsorbate atom. The apparatus includes a source of a beam of low energy electrons and a detector for detecting the intensity distribution of a DLEED pattern formed at the detector when the beam of low energy electrons is directed onto the surface of a crystal. A device responsive to the intensity distribution generates a signal corresponding to the distribution which represents a reconstructed amplitude of a wave form and is capable of being converted into a three dimensional image of the atomic environment of an adsorbate atom on the crystal surface.

  15. Atomizing apparatus for making polymer and metal powders and whiskers

    DOEpatents

    Otaigbe, Joshua U.; McAvoy, Jon M.; Anderson, Iver E.; Ting, Jason; Mi, Jia; Terpstra, Robert

    2003-03-18

    Method for making polymer particulates, such as spherical powder and whiskers, by melting a polymer material under conditions to avoid thermal degradation of the polymer material, atomizing the melt using gas jet means in a manner to form atomized droplets, and cooling the droplets to form polymer particulates, which are collected for further processing. Atomization parameters can be controlled to produce polymer particulates with controlled particle shape, particle size, and particle size distribution. For example, atomization parameters can be controlled to produce spherical polymer powders, polymer whiskers, and combinations of spherical powders and whiskers. Atomizing apparatus also is provided for atoomizing polymer and metallic materials.

  16. Method and apparatus for sampling atmospheric mercury

    DOEpatents

    Trujillo, Patricio E.; Campbell, Evan E.; Eutsler, Bernard C.

    1976-01-20

    A method of simultaneously sampling particulate mercury, organic mercurial vapors, and metallic mercury vapor in the working and occupational environment and determining the amount of mercury derived from each such source in the sampled air. A known volume of air is passed through a sampling tube containing a filter for particulate mercury collection, a first adsorber for the selective adsorption of organic mercurial vapors, and a second adsorber for the adsorption of metallic mercury vapor. Carbon black molecular sieves are particularly useful as the selective adsorber for organic mercurial vapors. The amount of mercury adsorbed or collected in each section of the sampling tube is readily quantitatively determined by flameless atomic absorption spectrophotometry.

  17. Apparatus and method for quantitative measurement of small differences in optical absorptivity between two samples using differential interferometry and the thermooptic effect

    DOEpatents

    Cremers, David A.; Keller, Richard A.

    1984-01-01

    An apparatus and method for the measurement of small differences in optical absorptivity of weakly absorbing solutions using differential interferometry and the thermooptic effect has been developed. Two sample cells are placed in each arm of an interferometer and are traversed by colinear probe and heating laser beams. The interrogation probe beams are recombined forming a fringe pattern, the intensity of which can be related to changes in optical pathlength of these laser beams through the cells. This in turn can be related to small differences in optical absorptivity which results in different amounts of sample heating when the heating laser beams are turned on, by the fact that the index of refraction of a liquid is temperature dependent. A critical feature of this invention is the stabilization of the optical path of the probe beams against drift. Background (solvent) absorption can then be suppressed by a factor of approximately 400. Solute absorptivities of about 10.sup.-5 cm.sup.-1 can then be determined in the presence of background absorptions in excess of 10.sup.-3 cm.sup.-1. In addition, the smallest absorption measured with the instant apparatus and method is about 5.times. 10.sup.-6 cm.sup.-1.

  18. Apparatus and method for quantitative measurement of small differences in optical absorptivity between two samples using differential interferometry and the thermooptic effect

    DOEpatents

    Cremers, D.A.; Keller, R.A.

    1982-06-08

    An apparatus and method for the measurement of small differences in optical absorptivity of weakly absorbing solutions using differential interferometry and the thermooptic effect has been developed. Two sample cells are placed in each arm of an interferometer and are traversed by colinear probe and heating laser beams. The interrogation probe beams are recombined forming a fringe pattern, the intensity of which can be related to changes in optical pathlength of these laser beams through the cells. This in turn can be related to small differences in optical absorptivity which results in different amounts of sample heating when the heating laser beams are turned on, by the fact that the index of refraction of a liquid is temperature dependent. A critical feature of this invention is the stabilization of the optical path of the probe beams against drift. Background (solvent) absorption can then be suppressed by a factor of approximately 400. Solute absorptivities of about 10/sup -5/ cm/sup -1/ can then be determined in the presence of background absorptions in excess of 10/sup -3/ cm/sup -1/. In addition, the smallest absorption measured with the instant apparatus and method is about 5 x 10/sup -6/ cm/sup -1/.

  19. Microporous structure with layered interstitial surface treatment, and method and apparatus for preparation thereof

    NASA Technical Reports Server (NTRS)

    Koontz, Steven L. (Inventor)

    1994-01-01

    A microporous structure with layered interstitial surface treatments, and method and apparatus for preparation thereof is presented. The structure is prepared by sequentially subjecting a uniformly surface-treated structure to atomic oxygen treatment to remove an outer layer of surface treatment to a generally uniform depth, and then surface treating the so exposed layer with another surface treating agent. The atomic oxygen/surface treatment steps may optionally be repeated, each successive time to a lesser depth, to produce a microporous structure having multilayered surface treatments. The apparatus employs at least one side arm from a main atomic oxygen-containing chamber. The side arm has characteristic relaxation times such that a uniform atomic oxygen dose rate is delivered to a specimen positioned transversely in the side arm spaced from the main gas chamber.

  20. Method of making polymer powders and whiskers as well as particulate products of the method and atomizing apparatus

    DOEpatents

    Otaigbe, Joshua U.; McAvoy, Jon M.; Anderson, Iver E.; Ting, Jason; Mi, Jia; Terpstra, Robert

    2001-01-09

    Method for making polymer particulates, such as spherical powder and whiskers, by melting a polymer material under conditions to avoid thermal degradation of the polymer material, atomizing the melt using gas jet means in a manner to form atomized droplets, and cooling the droplets to form polymer particulates, which are collected for further processing. Atomization parameters can be controlled to produce polymer particulates with controlled particle shape, particle size, and particle size distribution. For example, atomization parameters can be controlled to produce spherical polymer powders, polymer whiskers, and combinations of spherical powders and whiskers. Atomizing apparatus also is provided for atoomizing polymer and metallic materials.

  1. 21 CFR 862.2850 - Atomic absorption spectrophotometer for clinical use.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Atomic absorption spectrophotometer for clinical... Laboratory Instruments § 862.2850 Atomic absorption spectrophotometer for clinical use. (a) Identification. An atomic absorption spectrophotometer for clinical use is a device intended to identify and measure...

  2. 21 CFR 862.2850 - Atomic absorption spectrophotometer for clinical use.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Atomic absorption spectrophotometer for clinical... Laboratory Instruments § 862.2850 Atomic absorption spectrophotometer for clinical use. (a) Identification. An atomic absorption spectrophotometer for clinical use is a device intended to identify and measure...

  3. 21 CFR 862.2850 - Atomic absorption spectrophotometer for clinical use.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Atomic absorption spectrophotometer for clinical... Laboratory Instruments § 862.2850 Atomic absorption spectrophotometer for clinical use. (a) Identification. An atomic absorption spectrophotometer for clinical use is a device intended to identify and measure...

  4. 21 CFR 862.2850 - Atomic absorption spectrophotometer for clinical use.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Atomic absorption spectrophotometer for clinical... Laboratory Instruments § 862.2850 Atomic absorption spectrophotometer for clinical use. (a) Identification. An atomic absorption spectrophotometer for clinical use is a device intended to identify and measure...

  5. Apparatus and method for quantitative measurement of small differences in optical absorptivity between two samples using differential interferometry and the thermooptic effect

    DOEpatents

    Cremers, D.A.; Keller, R.A.

    1984-05-08

    An apparatus and method for the measurement of small differences in optical absorptivity of weakly absorbing solutions using differential interferometry and the thermooptic effect have been developed. Two sample cells are placed in each arm of an interferometer and are traversed by colinear probe and heating laser beams. The interrogation probe beams are recombined forming a fringe pattern, the intensity of which can be related to changes in optical path length of these laser beams through the cells. This in turn can be related to small differences in optical absorptivity which results in different amounts of sample heating when the heating laser beams are turned on, by the fact that the index of refraction of a liquid is temperature dependent. A critical feature of this invention is the stabilization of the optical path of the probe beams against drift. Background (solvent) absorption can then be suppressed by a factor of approximately 400. Solute absorptivities of about 10[sup [minus]5] cm[sup [minus]1] can then be determined in the presence of background absorptions in excess of 10[sup [minus]3] cm[sup [minus]1]. In addition, the smallest absorption measured with the instant apparatus and method is about 5 [times] 10[sup [minus]6] cm[sup [minus]1]. 6 figs.

  6. Determination of gold in geologic materials by solvent extraction and atomic-absorption spectrometry

    USGS Publications Warehouse

    Huffman, Claude; Mensik, J.D.; Riley, L.B.

    1967-01-01

    The two methods presented for the determination of traces of gold in geologic materials are the cyanide atomic-absorption method and the fire-assay atomic-absorption method. In the cyanide method gold is leached with a sodium-cyanide solution. The monovalent gold is then oxidized to the trivalent state and concentrated by extracting into methyl isobutyl ketone prior to estimation by atomic absorption. In the fire-assay atomic-absorption method, the gold-silver bead obtained from fire assay is dissolved in nitric and hydrochloric acids. Gold is then concentrated by extracting into methyl isobutyl ketone prior to determination by atomic absorption. By either method concentrations as low as 50 parts per billion of gold can be determined in a 15-gram sample.

  7. Apparatus Notes

    ERIC Educational Resources Information Center

    Eaton, Bruce G., Ed.

    1976-01-01

    Includes five brief articles on: solar-heating demonstration equipment, mercury or sodium vapor lamp spectroscopy, an apparatus for simulating variable stars, a voltage-to-frequency converter, and an introductory absorption experiment for low-energy beta particles. (MLH)

  8. Atomic vapor laser isotope separation of lead-210 isotope

    DOEpatents

    Scheibner, K.F.; Haynam, C.A.; Johnson, M.A.; Worden, E.F.

    1999-08-31

    An isotopically selective laser process and apparatus for removal of Pb-210 from natural lead that involves a one-photon near-resonant, two-photon resonant excitation of one or more Rydberg levels, followed by field ionization and then electrostatic extraction. The wavelength to the near-resonant intermediate state is counter propagated with respect to the second wavelength required to populate the final Rydberg state. This scheme takes advantage of the large first excited state cross section, and only modest laser fluences are required. The non-resonant process helps to avoid two problems: first, stimulated Raman Gain due to the nearby F=3/2 hyperfine component of Pb-207 and, second, direct absorption of the first transition process light by Pb-207. 5 figs.

  9. Atomic vapor laser isotope separation of lead-210 isotope

    DOEpatents

    Scheibner, Karl F.; Haynam, Christopher A.; Johnson, Michael A.; Worden, Earl F.

    1999-01-01

    An isotopically selective laser process and apparatus for removal of Pb-210 from natural lead that involves a one-photon near-resonant, two-photon resonant excitation of one or more Rydberg levels, followed by field ionization and then electrostatic extraction. The wavelength to the near-resonant intermediate state is counter propagated with respect to the second wavelength required to populate the final Rydberg state. This scheme takes advantage of the large first excited state cross section, and only modest laser fluences are required. The non-resonant process helps to avoid two problems: first, stimulated Raman Gain due to the nearby F=3/2 hyperfine component of Pb-207 and, second, direct absorption of the first transition process light by Pb-207.

  10. Experimental studies of a zeeman-tuned xenon laser differential absorption apparatus.

    PubMed

    Linford, G J

    1973-06-01

    A Zeeman-tuned cw xenon laser differential absorption device is described. The xenon laser was tuned by axial magnetic fields up to 5500 G generated by an unusually large water-cooled dc solenoid. Xenon laser lines at 3.37 micro, 3.51 micro, and 3.99 micro were tuned over ranges of 6 A, 6 A, and 11 A, respectively. To date, this apparatus has been used principally to study the details of formaldehyde absorption lines lying near the 3 .508-micro xenon laser transition. These experiments revealed that the observed absorption spectrum of formaldehyde exhibits a sufficiently unique spectral structure that the present technique may readily be used to measure relative concentrations of formaldehyde in samples of polluted air.

  11. Airfoil lance apparatus for homogeneous humidification and sorbent dispersion in a gas stream

    DOEpatents

    Myers, R.B.; Yagiela, A.S.

    1990-12-25

    An apparatus for spraying an atomized mixture into a gas stream comprises a stream line airfoil member having a large radius leading edge and a small radius trailing edge. A nozzle assembly pierces the trailing edge of the airfoil member and is concentrically surrounded by a nacelle which directs shielding gas from the interior of the airfoil member around the nozzle assembly. Flowable medium to be atomized and atomizing gas for atomizing the medium are supplied in concentric conduits to the nozzle. A plurality of nozzles each surrounded by a nacelle are spaced along the trailing edge of the airfoil member. 3 figs.

  12. Airfoil lance apparatus for homogeneous humidification and sorbent dispersion in a gas stream

    DOEpatents

    Myers, Robert B.; Yagiela, Anthony S.

    1990-12-25

    An apparatus for spraying an atomized mixture into a gas stream comprises a stream line airfoil member having a large radius leading edge and a small radius trailing edge. A nozzle assembly pierces the trailing edge of the airfoil member and is concentrically surrounded by a nacelle which directs shielding gas from the interior of the airfoil member around the nozzle assembly. Flowable medium to be atomized and atomizing gas for atomizing the medium are supplied in concentric conduits to the nozzle. A plurality of nozzles each surrounded by a nacelle are spaced along the trailing edge of the airfoil member.

  13. Laser sustained discharge nozzle apparatus for the production of an intense beam of high kinetic energy atomic species

    DOEpatents

    Cross, Jon B.; Cremers, David A.

    1988-01-01

    Laser sustained discharge apparatus for the production of intense beams of high kinetic energy atomic species. A portion of the plasma resulting from a laser sustained continuous optical discharge which generates energetic atomic species from a gaseous source thereof is expanded through a nozzle into a region of low pressure. The expanded plasma contains a significant concentration of the high kinetic energy atomic species which may be used to investigate the interaction of surfaces therewith. In particular, O-atoms having velocities in excess of 3.5 km/s can be generated for the purpose of studying their interaction with materials in order to develop protective materials for spacecraft which are exposed to such energetic O-atoms during operation in low earth orbit.

  14. Laser sustained discharge nozzle apparatus for the production of an intense beam of high kinetic energy atomic species

    DOEpatents

    Cross, J.B.; Cremers, D.A.

    1986-01-10

    Laser sustained discharge apparatus for the production of intense beams of high kinetic energy atomic species is described. A portion of the plasma resulting from a laser sustained continuous optical discharge which generates energetic atomic species from a gaseous source thereof is expanded through a nozzle into a region of low pressure. The expanded plasma contains a significant concentration of the high kinetic energy atomic species which may be used to investigate the interaction of surfaces therewith. In particular, O-atoms having velocities in excess of 3.5 km/s can be generated for the purpose of studying their interaction with materials in order to develop protective materials for spacecraft which are exposed to such energetic O-atoms during operation in low earth orbit.

  15. Plasma/Neutral-Beam Etching Apparatus

    NASA Technical Reports Server (NTRS)

    Langer, William; Cohen, Samuel; Cuthbertson, John; Manos, Dennis; Motley, Robert

    1989-01-01

    Energies of neutral particles controllable. Apparatus developed to produce intense beams of reactant atoms for simulating low-Earth-orbit oxygen erosion, for studying beam-gas collisions, and for etching semiconductor substrates. Neutral beam formed by neutralization and reflection of accelerated plasma on metal plate. Plasma ejected from coaxial plasma gun toward neutralizing plate, where turned into beam of atoms or molecules and aimed at substrate to be etched.

  16. Detector absorptivity measuring method and apparatus

    NASA Technical Reports Server (NTRS)

    Sheets, R. E. (Inventor)

    1976-01-01

    A method and apparatus for measuring the absorptivity of a radiation detector by making the detector an integral part of a cavity radiometer are described. By substituting the detector for the surface of the cavity upon which the radiation first impinges a comparison is made between the quantity of radiation incident upon the detector and the quantity reflected from the detector. The difference between the two is a measurement of the amount of radiation absorbed by the detector.

  17. 40 CFR Appendix A to Subpart C of... - Alternative Testing Methods Approved for Analyses Under the Safe Drinking Water Act

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Absorption D 3697-07 Atomic Absorption; Furnace 3113 B Axially viewed inductively coupled plasma-atomic... C Hydride Atomic Absorption 3114 B D 2972-08 B Axially viewed inductively coupled plasma-atomic emission spectrometry (AVICP-AES) 200.5, Revision 4.2. Barium Inductively Coupled Plasma 3120 B Atomic...

  18. METHOD AND APPARATUS FOR TRAPPING IONS IN A MAGNETIC FIELD

    DOEpatents

    Luce, J.S.

    1962-04-17

    A method and apparatus are described for trapping ions within an evacuated container and within a magnetic field utilizing dissociation and/or ionization of molecular ions to form atomic ions and energetic neutral particles. The atomic ions are magnetically trapped as a result of a change of charge-to- mass ratio. The molecular ions are injected into the container and into the path of an energetic carbon arc discharge which dissociates and/or ionizes a portion of the molecular ions into atomic ions and energetic neutrals. The resulting atomic ions are trapped by the magnetic field to form a circulating beam of atomic ions, and the energetic neutrals pass out of the system and may be utilized in a particle accelerator. (AEC)

  19. Surface tension mediated conversion of light to work

    DOEpatents

    Okawa, David; Pastine, Stefan J; Zettl, Alexander K; Frechet, Jean M. J

    2014-12-02

    Disclosed are a method and apparatus for converting light energy to mechanical energy by modification of surface tension on a supporting fluid. The apparatus comprises an object which may be formed as a composite object comprising a support matrix and a highly light absorptive material. The support matrix may comprise a silicon polymer. The highly light absorptive material may comprise vertically aligned carbon nanotubes (VANTs) embedded in the support matrix. The composite object is supported on a fluid. By exposing the highly light absorptive material to light, heat is generated, which changes the surface tension of the composite object, causing it to move physically within the fluid.

  20. Ion optical design of a collinear laser-negative ion beam apparatus.

    PubMed

    Diehl, C; Wendt, K; Lindahl, A O; Andersson, P; Hanstorp, D

    2011-05-01

    An apparatus for photodetachment studies on atomic and molecular negative ions of medium up to heavy mass (M ≃ 500) has been designed and constructed. Laser and ion beams are merged in the apparatus in a collinear geometry and atoms, neutral molecules and negative ions are detected in the forward direction. The ion optical design and the components used to optimize the mass resolution and the transmission through the extended field-free interaction region are described. A 90° sector field magnet with 50 cm bending radius in combination with two slits is used for mass dispersion providing a resolution of M∕ΔM≅800 for molecular ions and M∕ΔM≅400 for atomic ions. The difference in mass resolution for atomic and molecular ions is attributed to different energy distributions of the sputtered ions. With 1 mm slits, transmission from the source through the interaction region to the final ion detector was determined to be about 0.14%.

  1. 40 CFR Appendix A to Subpart C of... - Alternative Testing Methods Approved for Analyses Under the Safe Drinking Water Act

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... coupled plasma-atomic emission spectrometry (AVICP-AES) 200.5, Revision 4.2. 2 Arsenic Atomic Absorption... inductively coupled plasma-atomic emission spectrometry (AVICP-AES) 200.5, Revision 4.2. 2 Barium Inductively Coupled Plasma 3120 B Atomic Absorption; Direct 3111 D Atomic Absorption; Furnace 3113 B 3113 B-04 Axially...

  2. 40 CFR Appendix A to Subpart C of... - Alternative Testing Methods Approved for Analyses Under the Safe Drinking Water Act

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... coupled plasma-atomic emission spectrometry (AVICP-AES) 200.5, Revision 4.2. 2 Arsenic Atomic Absorption... inductively coupled plasma-atomic emission spectrometry (AVICP-AES) 200.5, Revision 4.2. 2 Barium Inductively Coupled Plasma 3120 B Atomic Absorption; Direct 3111 D Atomic Absorption; Furnace 3113 B 3113 B-04 Axially...

  3. Microporous structure with layered interstitial surface treatment, and method and apparatus for preparation thereof

    NASA Technical Reports Server (NTRS)

    Koontz, Steven L. (Inventor)

    1992-01-01

    A microporous structure with layered interstitial surface treatments, and the method and apparatus for its preparation are disclosed. The structure is prepared by sequentially subjecting a uniformly surface treated structure to atomic oxygen treatment to remove an outer layer of surface treatment to a generally uniform depth, and then surface treating the so exposed layer with another surface treating agent. The atomic oxygen/surface treatment steps may optionally be repeated, each successive time to a lesser depth, to produce a microporous structure having multilayered surface treatments. The apparatus employs at least one side arm from a main oxygen-containing chamber. The side arm has characteristic relaxation times such that a uniform atomic oxygen dose rate is delivered to a specimen positioned transversely in the side arm spaced from the main gas chamber.

  4. Incipient fire detection system

    DOEpatents

    Brooks, Jr., William K.

    1999-01-01

    A method and apparatus for an incipient fire detection system that receives gaseous samples and measures the light absorption spectrum of the mixture of gases evolving from heated combustibles includes a detector for receiving gaseous samples and subjecting the samples to spectroscopy and determining wavelengths of absorption of the gaseous samples. The wavelengths of absorption of the gaseous samples are compared to predetermined absorption wavelengths. A warning signal is generated whenever the wavelengths of absorption of the gaseous samples correspond to the predetermined absorption wavelengths. The method includes receiving gaseous samples, subjecting the samples to light spectroscopy, determining wavelengths of absorption of the gaseous samples, comparing the wavelengths of absorption of the gaseous samples to predetermined absorption wavelengths and generating a warning signal whenever the wavelengths of absorption of the gaseous samples correspond to the predetermined absorption wavelengths. In an alternate embodiment, the apparatus includes a series of channels fluidically connected to a plurality of remote locations. A pump is connected to the channels for drawing gaseous samples into the channels. A detector is connected to the channels for receiving the drawn gaseous samples and subjecting the samples to spectroscopy. The wavelengths of absorption are determined and compared to predetermined absorption wavelengths is provided. A warning signal is generated whenever the wavelengths correspond.

  5. Apparatus And Methods For Launching And Receiving A Broad Wavelength Range Source

    DOEpatents

    Von Drasek, William A.; Sonnenfroh, David; Allen, Mark G.; Stafford-Evans, Joy

    2006-02-28

    An apparatus and method for simultaneous detection of N gas species through laser radiation attenuation techniques is disclosed. Each of the N species has a spectral absorption band. N laser sources operate at a wavelength ?N in a spectral absorption band separated by the cutoff wavelength for single-mode transmission. Each laser source corresponds to a gas species and transmits radiation through an optical fiber constructed and arranged to provide single-mode transmission with minimal power loss.

  6. Simultaneous Atomic Absorption Spectrometry for Cadmium and Lead Determination in Wastewater: A Laboratory Exercise

    ERIC Educational Resources Information Center

    Correia, Paulo R. M.; Oliveira, Pedro V.

    2004-01-01

    The simultaneous determination of cadmium and lead by multi-element atomic absorption spectrometry with electrochemical atomization is proposed by employing a problem-based approach. The reports indicate that the students assimilated the principles of the simultaneous atomic absorption spectrometry (SIMAAS), the role of the chemical modifier, the…

  7. Method and apparatus for aerosol particle absorption spectroscopy

    DOEpatents

    Campillo, Anthony J.; Lin, Horn-Bond

    1983-11-15

    A method and apparatus for determining the absorption spectra, and other properties, of aerosol particles. A heating beam source provides a beam of electromagnetic energy which is scanned through the region of the spectrum which is of interest. Particles exposed to the heating beam which have absorption bands within the band width of the heating beam absorb energy from the beam. The particles are also illuminated by light of a wave length such that the light is scattered by the particles. The absorption spectra of the particles can thus be determined from an analysis of the scattered light since the absorption of energy by the particles will affect the way the light is scattered. Preferably the heating beam is modulated to simplify the analysis of the scattered light. In one embodiment the heating beam is intensity modulated so that the scattered light will also be intensity modulated when the particles absorb energy. In another embodiment the heating beam passes through an interferometer and the scattered light reflects the Fourier Transform of the absorption spectra.

  8. Method and apparatus for producing a thermal atomic oxygen beam

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor); Rutledge, Sharon K. (Inventor)

    1994-01-01

    Atomic oxygen atoms are routed to a material through a sufficiently tortuous path so that vacuum ultraviolet radiation is obstructed from arriving at the surface of the material. However, the material surface continues to be exposed to the atomic oxygen.

  9. Design considerations regarding an atomizer for multi-element electrothermal atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Katskov, Dmitri A.; Sadagov, Yuri M.

    2011-06-01

    The methodology of simultaneous multi-element electrothermal atomic absorption spectrometry (ETAAS-Electrothermal Atomic Absorption Spectrometry) stipulates rigid requirements to the design and operation of the atomizer. It must provide high degree of atomization for the group of analytes, invariant respective to the vaporization kinetics and heating ramp residence time of atoms in the absorption volume and absence of memory effects from major sample components. For the low resolution spectrometer with a continuum radiation source the reduced compared to traditional ETAAS (Electrothermal Atomic Absorption Spectrometry) sensitivity should be, at least partially, compensated by creating high density of atomic vapor in the absorption pulse. The sought-for characteristics were obtained for the 18 mm in length and 2.5 mm in internal diameter longitudinally heated graphite tube atomizer furnished with 2-4.5 mg of ring shaped carbon fiber yarn collector. The collector located next to the sampling port provides large substrate area that helps to keep the sample and its residue in the central part of the tube after drying. The collector also provides a "platform" effect that delays the vaporization and stipulates vapor release into absorption volume having already stabilized gas temperature. Due to the shape of external surface of the tube, presence of collector and rapid (about 10 °C/ms) heating, an inverse temperature distribution along the tube is attained at the beginnings of the atomization and cleaning steps. The effect is employed for cleaning of the atomizer using the set of short maximum power heating pulses. Preparation, optimal maintenance of the atomizer and its compliance to the multi-element determination requirements are evaluated and discussed. The experimental setup provides direct simultaneous determination of large group of element within 3-4 order concentration range. Limits of detection are close to those for sequential single element determination in Flame AAS with primary line source that is 50-1000 times higher than the limits obtainable with common ETAAS (Electrothermal Atomic Absorption Spectrometry) instrumentation.

  10. Flameless atomic-absorption determination of gold in geological materials

    USGS Publications Warehouse

    Meier, A.L.

    1980-01-01

    Gold in geologic material is dissolved using a solution of hydrobromic acid and bromine, extracted with methyl isobutyl ketone, and determined using an atomic-absorption spectrophotometer equipped with a graphite furnace atomizer. A comparison of results obtained by this flameless atomic-absorption method on U.S. Geological Survey reference rocks and geochemical samples with reported values and with results obtained by flame atomic-absorption shows that reasonable accuracy is achieved with improved precision. The sensitivity, accuracy, and precision of the method allows acquisition of data on the distribution of gold at or below its crustal abundance. ?? 1980.

  11. Flameless Atomic Absorption Spectroscopy: Effects of Nitrates and Sulfates.

    DTIC Science & Technology

    1980-05-01

    ATTACHED DDJ~P 1413 EDITION 01 INO, 6 5 IabSoLEr J UjN!LbAa~ A- i SELU 0 IONOF I tG 651 J Flameless Atomic Absorption Spectroscopy: Effects of Nitrates...analytical techniques, flameless atomic absorption is subject to matrix or interference effects. Upon heating, nitrate and sulfate salts decompose to...Eklund and J.E. Smith, Anal Chem, 51, 1205 (1979) R.H. Eklund and J.A. Holcombe, Anal Chim. Acta, 109, 97 (1979) FLAMELESS ATOMIC ABSORPTION

  12. [Study on lead absorption in pumpkin by atomic absorption spectrophotometry].

    PubMed

    Li, Zhen-Xia; Sun, Yong-Dong; Chen, Bi-Hua; Li, Xin-Zheng

    2008-07-01

    A study was carried out on the characteristic of lead absorption in pumpkin via atomic absorption spectrophotometer. The results showed that lead absorption amount in pumpkin increased with time, but the absorption rate decreased with time; And the lead absorption amount reached the peak in pH 7. Lead and cadmium have similar characteristic of absorption in pumpkin.

  13. 21 CFR 862.2850 - Atomic absorption spectrophotometer for clinical use.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Atomic absorption spectrophotometer for clinical... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862.2850 Atomic absorption spectrophotometer for clinical use. (a) Identification...

  14. Emilio G. Segrè - Patents

    Science.gov Websites

    neutrons to thermal energies. US 2,573,069 METHOD AND APPARATUS FOR MEASURING STRONG ALPHA EMITTERS - Segrà ¨, E. G.; October 30, 1951 (to the U.S. Atomic Energy Commission) This patent describes an apparatus and method for the determination of the strength of a strong alpha emitter. The apparatus is so

  15. Midinfrared absorption measured at a lambda/400 resolution with an atomic force microscope.

    PubMed

    Houel, Julien; Homeyer, Estelle; Sauvage, Sébastien; Boucaud, Philippe; Dazzi, Alexandre; Prazeres, Rui; Ortéga, Jean-Michel

    2009-06-22

    Midinfrared absorption can be locally measured using a detection combining an atomic force microscope and a pulsed excitation. This is illustrated for the midinfrared bulk GaAs phonon absorption and for the midinfrared absorption of thin SiO(2) microdisks. We show that the signal given by the cantilever oscillation amplitude of the atomic force microscope follows the spectral dependence of the bulk material absorption. The absorption spatial resolution achieved with microdisks is around 50 nanometer for an optical excitation around 22 micrometer wavelength.

  16. Absorption and emission spectra of Li atoms trapped in rare gas matrices

    NASA Astrophysics Data System (ADS)

    Wright, J. J.; Balling, L. C.

    1980-10-01

    Pulsed-dye-laser excitation has been used to investigate the optical absorption and emission spectra of Li atoms trapped in Ar, Kr, and Xe matrices at 10 °K. Attempts to stabilize Li atoms in a Ne matrix at 2 °K were unsuccessful. Results for all three rare gases were qualitatively the same. White light absorption scans showed a single absorption with three peaks centered near the free-atom 2s→2p transition wavelength. The intensity of fluorescence produced by dye-laser excitation within this absorption band was measured as a function of emission wavelength. Excitation of the longest- and shortest-wavelength absorption peaks produced identical emission profiles, but no distinct fluorescence signal was detected when the laser was tuned to the central absorption peaks, indicating that the apparent absorption triplet is actually the superposition of a singlet and a doublet absorption originating from two different trapping sites. No additional absorption bands were detected.

  17. Atomic Absorption, Atomic Fluorescence, and Flame Emission Spectrometry.

    ERIC Educational Resources Information Center

    Horlick, Gary

    1984-01-01

    This review is presented in six sections. Sections focus on literature related to: (1) developments in instrumentation, measurement techniques, and procedures; (2) performance studies of flames and electrothermal atomizers; (3) applications of atomic absorption spectrometry; (4) analytical comparisons; (5) atomic fluorescence spectrometry; and (6)…

  18. Evaluation of co-processed excipients used for direct compression of orally disintegrating tablets (ODT) using novel disintegration apparatus.

    PubMed

    Brniak, Witold; Jachowicz, Renata; Krupa, Anna; Skorka, Tomasz; Niwinski, Krzysztof

    2013-01-01

    The compendial method of evaluation of orodispersible tablets (ODT) is the same disintegration test as for conventional tablets. Since it does not reflect the disintegration process in the oral cavity, alternative methods are proposed that are more related to in vivo conditions, e.g. modified dissolution paddle apparatus, texture analyzer, rotating shaft apparatus, CCD camera application, or wetting time and water absorption ratio measurement. In this study, three different co-processed excipients for direct compression of orally disintegrating tablets were compared (Ludiflash, Pharmaburst, F-Melt). The properties of the prepared tablets such as tensile strength, friability, wetting time and water absorption ratio were evaluated. Disintegration time was measured using the pharmacopoeial method and the novel apparatus constructed by the authors. The apparatus was based on the idea of Narazaki et al., however it has been modified. Magnetic resonance imaging (MRI) was applied for the analysis of the disintegration mechanism of prepared tablets. The research has shown the significant effect of excipients, compression force, temperature, volume and kind of medium on the disintegration process. The novel apparatus features better correlation of disintegration time with in vivo results (R(2) = 0.9999) than the compendial method (R(2) = 0.5788), and presents additional information on the disintegration process, e.g. swelling properties.

  19. Ionisation of atomic hydrogen by positron impact

    NASA Technical Reports Server (NTRS)

    Spicher, Gottfried; Olsson, Bjorn; Raith, Wilhelm; Sinapius, Guenther; Sperber, Wolfgang

    1990-01-01

    With the crossed beam apparatus the relative impact-ionization cross section of atomic hydrogen by positron impact was measured. A layout of the scattering region is given. The first measurements on the ionization of atomic hydrogen by positron impact are also given.

  20. Double photoionization of atoms

    NASA Astrophysics Data System (ADS)

    Wiedenhoeft, Marco

    2003-10-01

    Double photoionization studies of atoms and molecules are new state-of-the-art studies providing a deeper knowledge of multi-electron excitations. This type of work advances the understanding of many-body problems. Double photoionization of atoms is of great interest to learn about electron-electron correlation and relaxation effects in atoms and molecules. In order to study double photoionization processes, a new electron-electron coincidence apparatus was built to carry out the measurements. I will present the apparatus I built as well as the results of the measurement of the triply-differential-cross-section (TDCS) for the predicted interference and Post-Collision-Interaction (PCI) effects in the Xenon N5O2,3 O2,3 Auger decay after 4d5/2 photoionization. Furthermore I present measurements for direct double photoionization of Helium at various photon energies.

  1. Method and apparatus for measuring butterfat and protein content using microwave absorption techniques

    DOEpatents

    Fryer, Michael O.; Hills, Andrea J.; Morrison, John L.

    2000-01-01

    A self calibrating method and apparatus for measuring butterfat and protein content based on measuring the microwave absorption of a sample of milk at several microwave frequencies. A microwave energy source injects microwave energy into the resonant cavity for absorption and reflection by the sample undergoing evaluation. A sample tube is centrally located in the resonant cavity passing therethrough and exposing the sample to the microwave energy. A portion of the energy is absorbed by the sample while another portion of the microwave energy is reflected back to an evaluation device such as a network analyzer. The frequency at which the reflected radiation is at a minimum within the cavity is combined with the scatter coefficient S.sub.11 as well as a phase change to calculate the butterfat content in the sample. The protein located within the sample may also be calculated in a likewise manner using the frequency, S.sub.11 and phase variables. A differential technique using a second resonant cavity containing a reference standard as a sample will normalize the measurements from the unknown sample and thus be self-calibrating. A shuttered mechanism will switch the microwave excitation between the unknown and the reference cavities. An integrated apparatus for measuring the butterfat content in milk using microwave absorption techniques is also presented.

  2. Experimental studies of electron impact depopulation of excited states of atoms: applications to laser development for fusion and isotope separation. Final report, 1 January 1977-30 June 1979

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lubell, M.S.

    1980-06-01

    Motivated by the need for measurements of metastable depopulation mechanisms of Ar and Kr in the KrF rare-gas monohalide excimer laser, an ultra-high vacuum triple crossed-beams apparatus has been designed, fabricated, and assembled for the purpose of studying electron scattering from excited states of Ar and Kr atoms. A beam of metastable rare gas atoms, produced by near-resonant charge transfer of rare gas ions with alkali neutral atoms, is crossed by an electron beam and a far-red laser beam along mutually orthogonal axes. A hemispherical electron monochromator-spectrometer pair is used to measure the cross section for electron scattering from themore » 2p/sub 9/ excited state of the rare gas atom. Testing of parts of the assembled apparatus has been completed.« less

  3. Determination of iridium in mafic rocks by atomic absorption

    USGS Publications Warehouse

    Grimaldi, F.S.; Schnepfe, M.M.

    1970-01-01

    Iridium is determined in mineralized mafic rocks by atomic absorption after fire-assay concentration into a gold bead. Interelement interferences in the atomic-absorption determination are removed and Ir sensitivity is increased by buffering the solutions with a mixture of copper and sodium sulphates. Substantial amounts of Ag, Al, Au, Bi, Ca, Cd, Co, Cr, Fe, Ho, Hg, K, La, Mg, Mn, Mo, Ni, Pb, Te, Ti, V, Y, Zn and platinum metals can be tolerated in the atomic-absorption determination. The sensitivity and detection limits are 3.2 and 0.25 ppm of Ir, respectively. ?? 1970.

  4. Apparatus and method for atmospheric pressure reactive atom plasma processing for shaping of damage free surfaces

    DOEpatents

    Carr,; Jeffrey, W [Livermore, CA

    2009-03-31

    Fabrication apparatus and methods are disclosed for shaping and finishing difficult materials with no subsurface damage. The apparatus and methods use an atmospheric pressure mixed gas plasma discharge as a sub-aperture polisher of, for example, fused silica and single crystal silicon, silicon carbide and other materials. In one example, workpiece material is removed at the atomic level through reaction with fluorine atoms. In this example, these reactive species are produced by a noble gas plasma from trace constituent fluorocarbons or other fluorine containing gases added to the host argon matrix. The products of the reaction are gas phase compounds that flow from the surface of the workpiece, exposing fresh material to the etchant without condensation and redeposition on the newly created surface. The discharge provides a stable and predictable distribution of reactive species permitting the generation of a predetermined surface by translating the plasma across the workpiece along a calculated path.

  5. Collisional redistribution of radiation. II - The effects of degeneracy on the equations of motion for the density matrix. III - The equation of motion for the correlation function and the scattered spectrum

    NASA Technical Reports Server (NTRS)

    Burnett, K.; Cooper, J.

    1980-01-01

    The effect of correlations between an absorber atom and perturbers in the binary-collision approximation are applied to degenerate atomic systems. A generalized absorption profile which specifies the final state of the atom after an absorption event is related to the total intensities of Rayleigh scattering and fluorescence from the atom. It is suggested that additional dynamical information to that obtainable from ordinary absorption experiments is required in order to describe redistributed atomic radiation. The scattering of monochromatic radiation by a degenerate atom is computed in a binary-collision approximation; an equation of motion is derived for the correlation function which is valid outside the quantum-regression regime. Solutions are given for the weak-field conditions in terms of generalized absorption and emission profiles that depend on the indices of the atomic multipoles.

  6. Method and apparatus for transmutation of atomic nuclei

    DOEpatents

    Maenchen, John Eric; Ruiz, Carlos Leon

    1998-01-01

    Insuring a constant supply of radioisotopes is of great importance to medicine and industry. This invention addresses this problem, and helps to solve it by introducing a new apparatus for transmutation of isotopes which enables swift and flexible production on demand.

  7. Vacuum pump apparatus

    DOEpatents

    Batzer, Thomas H.; Call, Wayne R.

    1985-01-01

    An improved cryopumping apparatus which comprises a cryopumping space which may be alternately opened and closed from the surrounding area by moveable panels, trubular cryopanels within said cryopumping space through which a coolant such as liquid helium may be passed, and an apparatus for spraying liquid argon onto said cylindrical cryopanels in order to enhance the cryogenic entrapment of such low-z ions, atoms, and molecules as hydrogen and helium.

  8. Determination of Calcium in Cereal with Flame Atomic Absorption Spectroscopy: An Experiment for a Quantitative Methods of Analysis Course

    ERIC Educational Resources Information Center

    Bazzi, Ali; Kreuz, Bette; Fischer, Jeffrey

    2004-01-01

    An experiment for determination of calcium in cereal using two-increment standard addition method in conjunction with flame atomic absorption spectroscopy (FAAS) is demonstrated. The experiment is intended to introduce students to the principles of atomic absorption spectroscopy giving them hands on experience using quantitative methods of…

  9. Triple effect absorption chiller utilizing two refrigeration circuits

    DOEpatents

    DeVault, Robert C.

    1988-01-01

    A triple effect absorption method and apparatus having a high coefficient of performance. Two single effect absorption circuits are combined with heat exchange occurring between a condenser and absorber of a high temperature circuit, and a generator of a low temperature circuit. The evaporators of both the high and low temperature circuits provide cooling to an external heat load.

  10. Method and apparatus for transmutation of atomic nuclei

    DOEpatents

    Maenchen, J.E.; Ruiz, C.L.

    1998-12-08

    Insuring a constant supply of radioisotopes is of great importance to medicine and industry. This invention addresses this problem, and helps to solve it by introducing a new apparatus for transmutation of isotopes which enables swift and flexible production on demand. 9 figs.

  11. Method and apparatus for transmutation of atomic nuclei

    DOEpatents

    Maenchen, J.E.; Ruiz, C.L.

    1998-06-09

    Insuring a constant supply of radioisotopes is of great importance to medicine and industry. This invention addresses this problem, and helps to solve it by introducing a new apparatus for transmutation of isotopes which enables swift and flexible production on demand. 9 figs.

  12. Efficient atom localization via probe absorption in an inverted-Y atomic system

    NASA Astrophysics Data System (ADS)

    Wu, Jianchun; Wu, Bo; Mao, Jiejian

    2018-06-01

    The behaviour of atom localization in an inverted-Y atomic system is theoretically investigated. For the atoms interacting with a weak probe field and several orthogonal standing-wave fields, their position information can be obtained by measuring the probe absorption. Compared with the traditional scheme, we couple the probe field to the transition between the middle and top levels. It is found that the probe absorption sensitively depends on the detuning and strength of the relevant light fields. Remarkably, the atom can be localized at a particular position in the standing-wave fields by coupling a microwave field to the transition between the two ground levels.

  13. Method of performing MRI with an atomic magnetometer

    DOEpatents

    Savukov, Igor Mykhaylovich; Matlashov, Andrei Nikolaevich; Espy, Michelle A.; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry; Zotev, Vadim Sergeyevich

    2012-11-06

    A method and apparatus are provided for performing an in-situ magnetic resonance imaging of an object. The method includes the steps of providing an atomic magnetometer, coupling a magnetic field generated by magnetically resonating samples of the object through a flux transformer to the atomic magnetometer and measuring a magnetic resonance of the atomic magnetometer.

  14. Method of performing MRI with an atomic magnetometer

    DOEpatents

    Savukov, Igor Mykhaylovich; Matlashov, Andrei Nikolaevich; Espy, Michelle A; Volegov, Petr Lvovich; Kraus, Jr., Robert Henry; Zotev, Vadim Sergeyevich

    2013-08-27

    A method and apparatus are provided for performing an in-situ magnetic resonance imaging of an object. The method includes the steps of providing an atomic magnetometer, coupling a magnetic field generated by magnetically resonating samples of the object through a flux transformer to the atomic magnetometer and measuring a magnetic resonance of the atomic magnetometer.

  15. Phase change thermal control materials, method and apparatus

    NASA Technical Reports Server (NTRS)

    Buckley, Theresa M. (Inventor)

    2001-01-01

    An apparatus and method for metabolic cooling and insulation of a user in a cold environment. In its preferred embodiment the apparatus is a highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The apparatus can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The apparatus may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the apparatus also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

  16. NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION AND MAINTENANCE OF THE PERKIN-ELMER ZEEMAN/5000 SYSTEM ATOMIC ABSORPTION SPECTROMETER (BCO-L-6.0)

    EPA Science Inventory

    The purpose of this SOP is to outline the start-up, calibration, operation, and maintenance procedures for the Perkin-Elmer 5000 atomic absorption spectrophotometer (PE 5000 AA), and the Perkin Elmer 5000 Zeeman graphite furnace atomic absorption spectrophotometer (PE 5000Z GFAA)...

  17. Atom Skimmers and Atom Lasers Utilizing Them

    NASA Technical Reports Server (NTRS)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  18. Uranium isotopes quantitatively determined by modified method of atomic absorption spectrophotometry

    NASA Technical Reports Server (NTRS)

    Lee, G. H.

    1967-01-01

    Hollow-cathode discharge tubes determine the quantities of uranium isotopes in a sample by using atomic absorption spectrophotometry. Dissociation of the uranium atoms allows a large number of ground state atoms to be produced, absorbing the incident radiation that is different for the two major isotopes.

  19. Pressurized feed-injection spray-forming apparatus

    DOEpatents

    Berry, R.A.; Fincke, J.R.; McHugh, K.M.

    1995-08-29

    A spray apparatus and method are disclosed for injecting a heated, pressurized liquid in a first predetermined direction into a pressurized gas flow that is flowing in a second predetermined direction, to provide for atomizing and admixing the liquid with the gas to form a two-phase mixture. A valve is also disposed within the injected liquid conduit to provide for a pulsed injection of the liquid and timed deposit of the atomized gas phase. Preferred embodiments include multiple liquid feed ports and reservoirs to provide for multiphase mixtures of metals, ceramics, and polymers. 22 figs.

  20. Pressurized feed-injection spray-forming apparatus

    DOEpatents

    Berry, Ray A.; Fincke, James R.; McHugh, Kevin M.

    1995-01-01

    A spray apparatus and method for injecting a heated, pressurized liquid in a first predetermined direction into a pressurized gas flow that is flowing in a second predetermined direction, to provide for atomizing and admixing the liquid with the gas to form a two-phase mixture. A valve is also disposed within the injected liquid conduit to provide for a pulsed injection of the liquid and timed deposit of the atomized gas phase. Preferred embodiments include multiple liquid feed ports and reservoirs to provide for multiphase mixtures of metals, ceramics, and polymers.

  1. Novel atomic absorption spectrometric and rapid spectrophotometric methods for the quantitation of paracetamol in saliva: application to pharmacokinetic studies.

    PubMed

    Issa, M M; Nejem, R M; El-Abadla, N S; Al-Kholy, M; Saleh, Akila A

    2008-01-01

    A novel atomic absorption spectrometric method and two highly sensitive spectrophotometric methods were developed for the determination of paracetamol. These techniques based on the oxidation of paracetamol by iron (III) (method I); oxidation of p-aminophenol after the hydrolysis of paracetamol (method II). Iron (II) then reacts with potassium ferricyanide to form Prussian blue color with a maximum absorbance at 700 nm. The atomic absorption method was accomplished by extracting the excess iron (III) in method II and aspirates the aqueous layer into air-acetylene flame to measure the absorbance of iron (II) at 302.1 nm. The reactions have been spectrometrically evaluated to attain optimum experimental conditions. Linear responses were exhibited over the ranges 1.0-10, 0.2-2.0 and 0.1-1.0 mug/ml for method I, method II and atomic absorption spectrometric method, respectively. A high sensitivity is recorded for the proposed methods I and II and atomic absorption spectrometric method value indicate: 0.05, 0.022 and 0.012 mug/ml, respectively. The limit of quantitation of paracetamol by method II and atomic absorption spectrometric method were 0.20 and 0.10 mug/ml. Method II and the atomic absorption spectrometric method were applied to demonstrate a pharmacokinetic study by means of salivary samples in normal volunteers who received 1.0 g paracetamol. Intra and inter-day precision did not exceed 6.9%.

  2. Novel Atomic Absorption Spectrometric and Rapid Spectrophotometric Methods for the Quantitation of Paracetamol in Saliva: Application to Pharmacokinetic Studies

    PubMed Central

    Issa, M. M.; Nejem, R. M.; El-Abadla, N. S.; Al-Kholy, M.; Saleh, Akila. A.

    2008-01-01

    A novel atomic absorption spectrometric method and two highly sensitive spectrophotometric methods were developed for the determination of paracetamol. These techniques based on the oxidation of paracetamol by iron (III) (method I); oxidation of p-aminophenol after the hydrolysis of paracetamol (method II). Iron (II) then reacts with potassium ferricyanide to form Prussian blue color with a maximum absorbance at 700 nm. The atomic absorption method was accomplished by extracting the excess iron (III) in method II and aspirates the aqueous layer into air-acetylene flame to measure the absorbance of iron (II) at 302.1 nm. The reactions have been spectrometrically evaluated to attain optimum experimental conditions. Linear responses were exhibited over the ranges 1.0-10, 0.2-2.0 and 0.1-1.0 μg/ml for method I, method II and atomic absorption spectrometric method, respectively. A high sensitivity is recorded for the proposed methods I and II and atomic absorption spectrometric method value indicate: 0.05, 0.022 and 0.012 μg/ml, respectively. The limit of quantitation of paracetamol by method II and atomic absorption spectrometric method were 0.20 and 0.10 μg/ml. Method II and the atomic absorption spectrometric method were applied to demonstrate a pharmacokinetic study by means of salivary samples in normal volunteers who received 1.0 g paracetamol. Intra and inter-day precision did not exceed 6.9%. PMID:20046743

  3. Vacuum Ultraviolet Absorption Measurements of Atomic Oxygen in a Shock Tube

    NASA Technical Reports Server (NTRS)

    Meyer, Scott Andrew

    1995-01-01

    The absorption of vacuum ultraviolet light by atomic oxygen has been measured in the Electric Arc-driven Shock Tube (EAST) Facility at NASA-Ames Research Center. This investigation demonstrates the instrumentation required to determine atomic oxygen concentrations from absorption measurements in impulse facilities. A shock wave dissociates molecular oxygen, producing a high temperature sample of atomic oxygen in the shock tube. A probe beam is generated with a Raman-shifted ArF excimer laser. By suitable tuning of the laser, absorption is measured over a range of wavelengths in the region of the atomic line at 130.49 nm. The line shape function is determined from measurements at atomic oxygen densities of 3 x 10(exp 17) and 9 x 10(exp 17)/cu cm. The broadening coefficient for resonance interactions is deduced from this data, and this value is in accord with available theoretical models.

  4. Vacuum Ultraviolet Absorption Measurements of Atomic Oxygen in a Shock Tube

    NASA Technical Reports Server (NTRS)

    Meyer, Scott Andrew

    1995-01-01

    The absorption of vacuum ultraviolet light by atomic oxygen has been measured in the Electric Arc-driven Shock Tube (EAST) Facility at NASA-Ames Research Center. This investigation demonstrates the instrumentation required to determine atomic oxygen concentrations from absorption measurements in impulse facilities. A shock wave dissociates molecular oxygen, producing a high temperature sample of atomic oxygen in the shock tube. A probe beam is generated with a Raman-shifted ArF excimer laser. By suitable tuning of the laser, absorption is measured over a range of wavelengths in the region of the atomic line at 130.49 nm. The line shape function is determined from measurements at atomic oxygen densities of 3x10(exp 17) and 9x10(exp 17) cm(exp -3). The broadening coefficient for resonance interactions is deduced from this data, and this value is in accord with available theoretical models.

  5. Vacuum Ultraviolet Absorption Measurements of Atomic Oxygen in a Shock Tube

    NASA Technical Reports Server (NTRS)

    Meyer, Scott Andrew

    1995-01-01

    The absorption of vacuum ultraviolet light by atomic oxygen has been measured in the Electric Arc-driven Shock Tube (EAST) Facility at NASA-Ames Research Center. This investigation demonstrates the instrumentation required to determine atomic oxygen concentrations from absorption measurements in impulse facilities. A shock wave dissociates molecular oxygen, producing a high temperature sample of atomic oxygen in the shock tube. A probe beam is generated with a Raman-shifted ArF excimer laser. By suitable tuning of the laser, absorption is measured over a range of wavelengths in the region of the atomic line at 130.49 nm. The line shape function is determined from measurements at atomic oxygen densities of 3 x 10(exp 17) and 9 x 10(exp 17) cm(exp -3). The broadening coefficient for resonance interactions is deduced from this data, and this value is in accord with available theoretical models.

  6. Production of dense plasmas in a hypocycloidal pinch apparatus

    NASA Technical Reports Server (NTRS)

    Lee, J. H.; Mcfarland, D. R.; Hohl, F.

    1977-01-01

    A high-power pinch apparatus consisting of disk electrodes was developed, and diagnostic measurements to study its mechanism of dense plasma production have been made. The collapse fronts of the current sheets are well organized, and dense plasma foci are produced on the axis with radial stability in excess of 5 microsec. A plasma density greater than 10 to the 18th power per cu cm is determined with Stark broadening and CO2 laser absorption. Essentially complete absorption of a high-energy CO2 laser beam has been observed. A plasma temperature of approximately 1 keV is measured with differential transmission of soft X-rays through thin foils. The advantages of this apparatus over the coaxial plasma focus are improvements in (1) plasma volume, (2) stability, (3) containment time, (4) access to additional heating by laser or electron beams, and (5) the possibility of scaling up to a multiple array for high-power operation.

  7. 2. VIEW IN ROOM 111, ATOMIC ABSORPTION BERYLLIUM ANALYSIS LABORATORY. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. VIEW IN ROOM 111, ATOMIC ABSORPTION BERYLLIUM ANALYSIS LABORATORY. AIR FILTERS AND SWIPES ARE DISSOLVED WITH ACIDS AND THE REMAINING RESIDUES ARE SUSPENDED IN NITRIC ACID SOLUTION. THE SOLUTION IS PROCESSED THROUGH THE ATOMIC ABSORPTION SPECTROPHOTOMETER TO DETECT THE PRESENCE AND LEVELS OF BERYLLIUM. - Rocky Flats Plant, Health Physics Laboratory, On Central Avenue between Third & Fourth Streets, Golden, Jefferson County, CO

  8. U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION, AND MAINTENANCE OF THE PERKIN-ELMER ZEEMAN/5000 SYSTEM ATOMIC ABSORPTION SPECTROPHOTOMETER (BCO-L-6.0)

    EPA Science Inventory

    The purpose of this SOP is to outline the start-up, calibration, operation, and maintenance procedures for the Perkin-Elmer 5000 atomic absorption spectrophotometer (PE 5000 AA), and the Perkin Elmer 5000 Zeeman graphite furnace atomic absorption spectrophotometer (PE 5000Z GFAA)...

  9. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    DOEpatents

    Phillips, Benjamin A.; Zawacki, Thomas S.; Marsala, Joseph

    1994-11-29

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium.

  10. Method and apparatus for enhancing laser absorption sensitivity

    NASA Technical Reports Server (NTRS)

    Webster, Christopher R. (Inventor)

    1987-01-01

    A simple optomechanical method and apparatus is described for substantially reducing the amplitude of unwanted multiple interference fringes which often limit the sensitivities of tunable laser absorption spectrometers. An exterior cavity is defined by partially transmissible surfaces such as a laser exit plate, a detector input, etc. That cavity is spoiled by placing an oscillating plate in the laser beam. For tunable diode laser spectroscopy in the mid-infrared region, a Brewster-plate spoiler allows the harmonic detection of absorptances of less than 10 to the -5 in a single laser scan. Improved operation is achieved without subtraction techniques, without complex laser frequency modulation, and without distortion of the molecular lineshape signal. The technique is applicable to tunable lasers operating from UV to IR wavelengths and in spectrometers which employ either short or long pathlengths, including the use of retroreflectors or multipass cells.

  11. Embedded dielectric water "atom" array for broadband microwave absorber based on Mie resonance

    NASA Astrophysics Data System (ADS)

    Gogoi, Dhruba Jyoti; Bhattacharyya, Nidhi Saxena

    2017-11-01

    A wide band microwave absorber at X-band frequency range is demonstrated numerically and experimentally by embedding a simple rectangular structured dielectric water "atom" in flexible silicone substrate. The absorption peak of the absorber is tuned by manipulating the size of the dielectric water "atom." The frequency dispersive permittivity property of the water "atom" shows broadband absorption covering the entire X-band above 90% efficiency with varying the size of the water "atom." Mie resonance of the proposed absorber provides the desired impedance matching condition at the air-absorber interface across a wide frequency range in terms of electric and magnetic resonances. Multipole decomposition of induced current densities is used to identify the nature of observed resonances. Numerical absorptivity verifies that the designed absorber is polarization insensitive for normal incidence and can maintain an absorption bandwidth of more than 2 GHz in a wide-angle incidence. Additionally, the tunability of absorption property with temperature is shown experimentally.

  12. Do Atoms Really "Emit" Absorption Lines?

    ERIC Educational Resources Information Center

    Brecher, Kenneth

    1991-01-01

    Presents three absorption line sources that enhance student understanding of the phenomena associated with the interaction of light with matter and help dispel the misconception that atoms "emit" absorption lines. Sources include neodymium, food coloring and other common household liquids, and fluorescent materials. (MDH)

  13. Determination of trace and minor elements in alloys by atomic-absorption spectroscopy using an induction-heated graphite-well furnace as atom source-II.

    PubMed

    Ashy, M A; Headridge, J B; Sowerbutts, A

    1974-06-01

    Results are presented for the atomic-absorption spectrophotometric determination of zinc in aluminium and aluminium-silicon alloys, and aluminium, antimony and tin in steels, by means of solid samples dropped into an induction-heated graphite-well furnace to produce the atomic vapour.

  14. Determination of urinary manganese by the direct chelation-extraction method and flameless atomic absorption spectrophotometry.

    PubMed Central

    Watanabe, T; Tokunaga, R; Iwahana, T; Tati, M; Ikeda, M

    1978-01-01

    The direct chelation-extraction method, originally developed by Hessel (1968) for blood lead analysis, has been successfully applied to urinalysis for manganese. The analyses of 35 urine samples containing up to 100 microgram/1 of manganese from manganese-exposed workers showed that the data obtained by this method agree well with those by wet digestion-flame atomic absorption spectrophotometry and also by flameless atomic absorption spectrophotometry. PMID:629893

  15. [Determination of trace cobalt in human urine by graphite furnace atomic absorption spectrometr].

    PubMed

    Zhong, L X; Ding, B M; Jiang, D; Liu, D Y; Yu, B; Zhu, B L; Ding, L

    2016-05-20

    To establish a method to determine cobalt in human urine by graphite furnace atomic absorption spectrometry. Urine with 2% nitric acid diluted two-fold, to quantify the curve, graphite furnace atomic absorption spectrometric detection. Co was linear within 2.5~40.0 ng/ml with r>0.999. Spike experiment showed that Co received good recovery rate, which was 90.8%~94.8%. Intra-assay precisions were 3.2%~5.1% for Co, inter-assay precisions were 4.4%~5.2% for Co. The method by using graphite furnace atomic absorption spectrometr to determine urine Co was fast, accurate and with low matrix effect. It could meet the requirement in GBZ/T 210.5-2008.

  16. Generator-Absorber heat exchange transfer apparatus and method using an intermediate liquor

    DOEpatents

    Phillips, Benjamin A.; Zawacki, Thomas S.

    1996-11-05

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium where the working solution has an intermediate liquor concentration.

  17. Comparison of two methods for blood lead analysis in cattle: graphite-furnace atomic absorption spectrometry and LeadCare(R) II system.

    PubMed

    Bischoff, Karyn; Gaskill, Cynthia; Erb, Hollis N; Ebel, Joseph G; Hillebrandt, Joseph

    2010-09-01

    The current study compared the LeadCare(R) II test kit system with graphite-furnace atomic absorption spectrometry for blood lead (Pb) analysis in 56 cattle accidentally exposed to Pb in the field. Blood Pb concentrations were determined by LeadCare II within 4 hr of collection and after 72 hr of refrigeration. Blood Pb concentrations were determined by atomic absorption spectrometry, and samples that were coagulated (n = 12) were homogenized before analysis. There was strong rank correlation (R(2) = 0.96) between atomic absorption and LeadCare II (within 4 hr of collection), and a conversion formula was determined for values within the observed range (3-91 mcg/dl, although few had values >40 mcg/dl). Median and mean blood pb concentrations for atomic absorption were 7.7 and 15.9 mcg/dl, respectively; for LeadCare II, medians were 5.2 mcg/dl at 4 hr and 4.9 mcg/dl at 72 hr, and means were 12.4 and 11.7, respectively. LeadCare II results at 4 hr strongly correlated with 72 hr results (R(2) = 0.96), but results at 72 hr were lower (P < 0.01). There was no significant difference between coagulated and uncoagulated samples run by atomic absorption. Although there have been several articles that compared LeadCare with other analytical techniques, all were for the original system, not LeadCare II. The present study indicated that LeadCare II results correlated well with atomic absorption over a wide range of blood Pb concentrations and that refrigerating samples for up to 72 hr before LeadCare II analysis was acceptable for clinical purposes.

  18. Apparatus for obtaining an X-ray image

    DOEpatents

    Watanabe, Eiji

    1979-01-01

    A computed tomography apparatus in which a fan-shaped X-ray beam is caused to pass through a section of an object, enabling absorption detection on the opposite side of the object by a detector comprising a plurality of discrete detector elements. An electron beam generating the X-ray beam by impacting upon a target is caused to rotate over the target.

  19. Documentation of the space station/aircraft acoustic apparatus

    NASA Technical Reports Server (NTRS)

    Clevenson, Sherman A.

    1987-01-01

    This paper documents the design and construction of the Space Station/Aircraft Acoustic Apparatus (SS/AAA). Its capabilities both as a space station acoustic simulator and as an aircraft acoustic simulator are described. Also indicated are the considerations which ultimately resulted in man-rating the SS/AAA. In addition, the results of noise surveys and reverberation time and absorption coefficient measurements are included.

  20. Femtosecond Chirp-Free Transient Absorption Method And Apparatus

    DOEpatents

    McBranch, Duncan W.; Klimov, Victor I.

    2001-02-20

    A method and apparatus for femtosecond transient absorption comprising phase-sensitive detection, spectral scanning and simultaneous controlling of a translation stage to obtain TA spectra information having at least a sensitivity two orders of magnitude higher than that for single-shot methods, with direct, simultaneous compensation for chirp as the data is acquired. The present invention includes a amplified delay translation stage which generates a splittable frequency-doubled laser signal at a predetermined frequency f, a controllable means for synchronously modulating one of the laser signals at a repetition rate of f/2, applying the laser signals to a material to be sample, and acquiring data from the excited sample while simultaneously controlling the controllable means for synchronously modulating.

  1. Identification of B-K near edge x-ray absorption fine structure peaks of boron nitride thin films prepared by sputtering deposition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Niibe, Masahito; Miyamoto, Kazuyoshi; Mitamura, Tohru

    2010-09-15

    Four {pi}{sup *} resonance peaks were observed in the B-K near edge x-ray absorption fine structure spectra of boron nitride thin films prepared by magnetron sputtering. In the past, these peaks have been explained as the K-absorption of boron atoms, which are present in environment containing nitrogen vacancies, the number of which is 1-3 corresponding to the three peaks at higher photon energy. However, the authors found that there was a strong correlation between the intensities of these three peaks and that of O-K absorption after wide range scanning and simultaneous measurement of nitrogen and oxygen K-absorptions of the BNmore » films. Therefore, the authors conclude that these three peaks at the higher energy side correspond to boron atoms bound to one-to-three oxygen atoms instead of three nitrogen atoms surrounding the boron atom in the h-BN structure. The result of the first-principles calculation with a simple cluster model supported the validity of this explanation.« less

  2. Phase change material thermal capacitor clothing

    NASA Technical Reports Server (NTRS)

    Buckley, Theresa M. (Inventor)

    2005-01-01

    An apparatus and method for metabolic cooling and insulation of a user in a cold environment. In its preferred embodiment the apparatus is a highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The apparatus can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The apparatus may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the apparatus also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

  3. Visualizing the Solute Vaporization Interference in Flame Atomic Absorption Spectroscopy

    ERIC Educational Resources Information Center

    Dockery, Christopher R.; Blew, Michael J.; Goode, Scott R.

    2008-01-01

    Every day, tens of thousands of chemists use analytical atomic spectroscopy in their work, often without knowledge of possible interferences. We present a unique approach to study these interferences by using modern response surface methods to visualize an interference in which aluminum depresses the calcium atomic absorption signal. Calcium…

  4. Speciation analysis of arsenic in biological matrices by automated hydride generation-cryotrapping-atomic absorption spectrometry with multiple microflame quartz tube atomizer (multiatomizer).

    EPA Science Inventory

    This paper describes an automated system for the oxidation state specific speciation of inorganic and methylated arsenicals by selective hydride generation - cryotrapping- gas chromatography - atomic absorption spectrometry with the multiatomizer. The corresponding arsines are ge...

  5. [Determination of metal elements in Achyranthis bidentatae radix from various habitats].

    PubMed

    Tu, Wan-Qian; Zhang, Liu-Ji

    2011-12-01

    To establish an atomic absorption spectrometry method for determination of the contents of metal elements in Achyranthis Bidentatae Radix and analyze 21 batches of samples from different areas. Fe, Mn, Ca, Mg, K, Zn and Cu were detected by atomic absorption spectrometry with hydrogen flame detector, Pb, As and Cd were detected by graphite furnace atomic absorption, Hg was detected by cold atomic absorption. The heavy metal contents met the requirement of Chinese Pharmacopoeia. The contents of K, Mg, Cu and Mn in the samples of geo-authentic areas were higher,while the contents of Fe, Zn, Hg and Pb in the samples of non-authentic areas were higher. This method is sample, accurate, repeatable and could be used to evaluate the quality of Achyranthis Bidentatae Radix.

  6. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Burrow, O.; Carroll, A.; Chattopadhyay, S.

    A cold atom interferometer is being developed using 85Rb atoms towards a search for the dark contents of the vacuum, and as a test stand for inertial sensing applications. Here we outline the current status of the experiment and report the observation of Ramsey interference fringes in the apparatus.

  7. The Free-Free Absorption Coefficients of the Negative Helium Ion

    NASA Astrophysics Data System (ADS)

    John, T. L.

    1994-08-01

    Free-free absorption coefficients of the negative helium ion are calculated by a phaseshift approximation, using continuum data that accurately account for electron-atom correlation and polarization. The approximation is considered to yield results within a few per cent of numerical values for wavelengths greater than 1 m, over the temperature range 1400-10080 K. These coefficients are expected to give the best current estimates of He - continuous absorption. Key words: atomic data - atomic processes - stars: atmospheres - infrared: general.

  8. Absorption of infrared radiation by electrons in the field of a neutral hydrogen atom

    NASA Technical Reports Server (NTRS)

    Stallcop, J. R.

    1974-01-01

    An analytical expression for the absorption coefficient is developed from a relationship between the cross-section for inverse bremsstrahlung absorption and the cross-section for electron-atom momentum transfer; it is accurate for those photon frequencies v and temperatures such that hv/kT is small. The determination of the absorption of infrared radiation by free-free transitions of the negative hydrogen ion has been extended to higher temperatures. A simple analytical expression for the absorption coefficient has been derived.

  9. Method and apparatus for noble gas atom detection with isotopic selectivity

    DOEpatents

    Hurst, G. Samuel; Payne, Marvin G.; Chen, Chung-Hsuan; Parks, James E.

    1984-01-01

    Apparatus and methods of operation are described for determining, with isotopic selectivity, the number of noble gas atoms in a sample. The analysis is conducted within an evacuated chamber which can be isolated by a valve from a vacuum pumping system capable of producing a pressure of 10.sup.-8 Torr. Provision is made to pass pulses of laser beams through the chamber, these pulses having wavelengths appropriate for the resonance ionization of atoms of the noble gas under analysis. A mass filter within the chamber selects ions of a specific isotope of the noble gas, and means are provided to accelerate these selected ions sufficiently for implantation into a target. Specific types of targets are discussed. An electron measuring device produces a signal relatable to the number of ions implanted into the target and thus to the number of atoms of the selected isotope of the noble gas removed from the gas sample. The measurement can be continued until a substantial fraction, or all, of the atoms in the sample have been counted. Furthermore, additional embodiments of the apparatus are described for bunching the atoms of a noble gas for more rapid analysis, and for changing the target for repetitive cycling of the gas in the chamber. The number of repetitions of the cyclic steps depend upon the concentration of the isotope of interest, the separative efficiency of the mass filter, etc. The cycles are continued until a desired selectivity is achieved. Also described are components and a method of operation for a pre-enrichment operation for use when an introduction of a total sample would elevate the pressure within the chamber to levels in excess of those for operation of the mass filter, specifically a quadrupole mass filter. Specific examples of three noble gas isotope analyses are described.

  10. Three-dimensional atom localization via electromagnetically induced transparency in a three-level atomic system.

    PubMed

    Wang, Zhiping; Cao, Dewei; Yu, Benli

    2016-05-01

    We present a new scheme for three-dimensional (3D) atom localization in a three-level atomic system via measuring the absorption of a weak probe field. Owing to the space-dependent atom-field interaction, the position probability distribution of the atom can be directly determined by measuring the probe absorption. It is found that, by properly varying the parameters of the system, the probability of finding the atom in 3D space can be almost 100%. Our scheme opens a promising way to achieve high-precision and high-efficiency 3D atom localization, which provides some potential applications in laser cooling or atom nano-lithography via atom localization.

  11. Micro determination of plasma and erythrocyte copper by atomic absorption spectrophotometry

    PubMed Central

    Blomfield, Jeanette; Macmahon, R. A.

    1969-01-01

    The free and total plasma copper and total erythrocyte copper levels have been determined by simple, yet sensitive and highly specific methods, using atomic absorption spectrophotometry. For total copper determination, the copper was split from its protein combination in plasma or red cells by the action of hydrochloric acid at room temperature. The liberated copper was chelated by ammonium pyrrolidine dithiocarbamate and extracted into n-butyl acetate by shaking and the organic extract was aspirated into the atomic absorption spectrophotometer flame. The entire procedure was carried out in polypropylene centrifuge tubes, capped during shaking. For the free plasma copper measurement the hydrochloric acid step was omitted. Removal of the plasma or erythrocyte proteins was found to be unnecessary, and, in addition, the presence of trichloracetic acid caused an appreciable lowering of absorption. Using a double-beam atomic absorption spectrophotometer and scale expansion × 10, micro methods have been derived for determining the total copper of plasma or erythrocytes with 0·1 ml of sample, and the free copper of plasma with 0·5 ml. The macro plasma copper method requires 2 ml of plasma and is suitable for use with single-beam atomic absorption spectrophotometers. With blood from 50 blood donors, normal ranges of plasma and erythrocyte copper have been determined. PMID:5776543

  12. Ultraviolet absorption experiment MA-059

    NASA Technical Reports Server (NTRS)

    Donahue, T. M.; Hudson, R. D.; Anderson, J.; Kaufman, F.; Mcelroy, M. B.

    1976-01-01

    The ultraviolet absorption experiment performed during the Apollo Soyuz mission involved sending a beam of atomic oxygen and atomic nitrogen resonance radiation, strong unabsorbable oxygen and nitrogen radiation, and visual radiation, all filling the same 3 deg-wide field of view from the Apollo to the Soyuz. The radiation struck a retroreflector array on the Soyuz and was returned to a spectrometer onboard the Apollo. The density of atomic oxygen and atomic nitrogen between the two spacecraft was measured by observing the amount of resonance radiation absorbed when the line joining Apollo and Soyuz was perpendicular to their velocity with respect to the ambient atmosphere. Information concerning oxygen densities was also obtained by observation of resonantly fluorescent light. The absorption experiments for atomic oxygen and atomic nitrogen were successfully performed at a range of 500 meters, and abundant resonance fluorescence data were obtained.

  13. Metal atomization spray nozzle

    DOEpatents

    Huxford, Theodore J.

    1993-01-01

    A spray nozzle for a magnetohydrodynamic atomization apparatus has a feed passage for molten metal and a pair of spray electrodes mounted in the feed passage. The electrodes, diverging surfaces which define a nozzle throat and diverge at an acute angle from the throat. Current passes through molten metal when fed through the throat which creates the Lorentz force necessary to provide atomization of the molten metal.

  14. Mapping the amide I absorption in single bacteria and mammalian cells with resonant infrared nanospectroscopy

    NASA Astrophysics Data System (ADS)

    Baldassarre, L.; Giliberti, V.; Rosa, A.; Ortolani, M.; Bonamore, A.; Baiocco, P.; Kjoller, K.; Calvani, P.; Nucara, A.

    2016-02-01

    Infrared (IR) nanospectroscopy performed in conjunction with atomic force microscopy (AFM) is a novel, label-free spectroscopic technique that meets the increasing request for nano-imaging tools with chemical specificity in the field of life sciences. In the novel resonant version of AFM-IR, a mid-IR wavelength-tunable quantum cascade laser illuminates the sample below an AFM tip working in contact mode, and the repetition rate of the mid-IR pulses matches the cantilever mechanical resonance frequency. The AFM-IR signal is the amplitude of the cantilever oscillations driven by the thermal expansion of the sample after absorption of mid-IR radiation. Using purposely nanofabricated polymer samples, here we demonstrate that the AFM-IR signal increases linearly with the sample thickness t for t \\gt 50 nm, as expected from the thermal expansion model of the sample volume below the AFM tip. We then show the capability of the apparatus to derive information on the protein distribution in single cells through mapping of the AFM-IR signal related to the amide-I mid-IR absorption band at 1660 cm-1. In Escherichia Coli bacteria we see how the topography changes, observed when the cell hosts a protein over-expression plasmid, are correlated with the amide I signal intensity. In human HeLa cells we obtain evidence that the protein distribution in the cytoplasm and in the nucleus is uneven, with a lateral resolution better than 100 nm.

  15. Determination of Copper by Graphite Furnace Atomic Absorption Spectrophotometry: A Student Exercise in Instrumental Methods of Analysis.

    ERIC Educational Resources Information Center

    Williamson, Mark A.

    1989-01-01

    Discusses a student exercise which requires the optimizing of the charring and atomization temperatures by producing a plot of absorbance versus temperature for each temperature parameter. Notes that although the graphite furnace atomic absorption spectroscopy technique has widespread industrial use, there are no published, structured experiments…

  16. Nanoscopic electrode molecular probes

    DOEpatents

    Krstic, Predrag S [Knoxville, TN; Meunier, Vincent [Knoxville, TN

    2012-05-22

    The present invention relates to a method and apparatus for enhancing the electron transport property measurements of a molecule when the molecule is placed between chemically functionalized carbon-based nanoscopic electrodes to which a suitable voltage bias is applied. The invention includes selecting a dopant atom for the nanoscopic electrodes, the dopant atoms being chemically similar to atoms present in the molecule, and functionalizing the outer surface and terminations of the electrodes with the dopant atoms.

  17. Method and apparatus of measuring unburned carbon in fly ash

    DOEpatents

    Brown, Robert C.

    1991-12-03

    A method and apparatus are shown to measure unburned carbon particles in the exhaust of a combustor. Photoacoustic absorption spectrometry is employed to measure the presence of the unburned carbon. Especially helpful in these measurements is a vertically elongated photoacoustic cell in which high flow velocities are maintained to prevent particles from settling. These measurements are useful in determining the efficiency of coal-fired combustors.

  18. A Mechanical Apparatus for Hands-On Experience with the Morse Potential

    ERIC Educational Resources Information Center

    Everest, Michael A.

    2010-01-01

    A simple pulley apparatus is described that gives the student hands-on experience with the Morse potential. Students develop an internalized sense of what a covalent bond would feel like if atoms in a molecule could be manipulated by hand. This kinesthetic learning enhances the student's understanding and intuition of several chemical phenomena.…

  19. Loss-free method of charging accumulator rings

    DOEpatents

    Maschke, Alfred W.

    1979-01-01

    A method for the production of high current pulses of heavy ions having an atomic weight greater than 100. Also a linear accelerator based apparatus for carrying out said method. Pulses formed by the method of the subject invention are suitable for storage in a storage ring. The accumulated pulses may be used in inertial fusion apparatus.

  20. Photon absorption potential coefficient as a tool for materials engineering

    NASA Astrophysics Data System (ADS)

    Akande, Raphael Oluwole; Oyewande, Emmanuel Oluwole

    2016-09-01

    Different atoms achieve ionizations at different energies. Therefore, atoms are characterized by different responses to photon absorption in this study. That means there exists a coefficient for their potential for photon absorption from a photon source. In this study, we consider the manner in which molecular constituents (atoms) absorb photon from a photon source. We observe that there seems to be a common pattern of variation in the absorption of photon among the electrons in all atoms on the periodic table. We assume that the electrons closest to the nucleus (En) and the electrons closest to the outside of the atom (Eo) do not have as much potential for photon absorption as the electrons at the middle of the atom (Em). The explanation we give to this effect is that the En electrons are embedded within the nuclear influence, and similarly, Eo electrons are embedded within the influence of energies outside the atom that there exists a low potential for photon absorption for them. Unlike En and Eo, Em electrons are conditioned, such that there is a quest for balance between being influenced either by the nuclear force or forces external to the atom. Therefore, there exists a higher potential for photon absorption for Em electrons than for En and Eo electrons. The results of our derivations and analysis always produce a bell-shaped curve, instead of an increasing curve as in the ionization energies, for all elements in the periodic table. We obtained a huge data of PAPC for each of the several materials considered. The point at which two or more PAPC values cross one another is termed to be a region of conflicting order of ionization, where all the atoms absorb equal portion of the photon source at the same time. At this point, a greater fraction of the photon source is pumped into the material which could lead to an explosive response from the material. In fact, an unimaginable and unreported phenomenon (in physics) could occur, when two or more PAPCs cross, and the material is able to absorb more than that the photon source could provide, at this point. These resulting effects might be of immense materials engineering applications.

  1. Attosecond transient absorption of argon atoms in the vacuum ultraviolet region: line energy shifts versus coherent population transfer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cao, Wei; Warrick, Erika R.; Neumark, Daniel M.

    Using attosecond transient absorption, the dipole response of an argon atom in the vacuum ultraviolet (VUV) region is studied when an external electromagnetic field is present. An isolated attosecond VUV pulse populates Rydberg states lying 15 eV above the argon ground state. A synchronized few-cycle near infrared (NIR) pulse modifies the oscillating dipoles of argon impulsively, leading to alterations in the VUV absorption spectra. As the NIR pulse is delayed with respect to the VUV pulse, multiple features in the absorption profile emerge simultaneously including line broadening, sideband structure, sub-cycle fast modulations, and 5-10 fs slow modulations. These features indicatemore » the coexistence of two general processes of the light-matter interaction: the energy shift of individual atomic levels and coherent population transfer between atomic eigenstates, revealing coherent superpositions. Finally, an intuitive formula is derived to treat both effects in a unifying framework, allowing one to identify and quantify the two processes in a single absorption spectrogram.« less

  2. Attosecond transient absorption of argon atoms in the vacuum ultraviolet region: line energy shifts versus coherent population transfer

    NASA Astrophysics Data System (ADS)

    Cao, Wei; Warrick, Erika R.; Neumark, Daniel M.; Leone, Stephen R.

    2016-01-01

    Using attosecond transient absorption, the dipole response of an argon atom in the vacuum ultraviolet (VUV) region is studied when an external electromagnetic field is present. An isolated attosecond VUV pulse populates Rydberg states lying 15 eV above the argon ground state. A synchronized few-cycle near infrared (NIR) pulse modifies the oscillating dipoles of argon impulsively, leading to alterations in the VUV absorption spectra. As the NIR pulse is delayed with respect to the VUV pulse, multiple features in the absorption profile emerge simultaneously including line broadening, sideband structure, sub-cycle fast modulations, and 5-10 fs slow modulations. These features indicate the coexistence of two general processes of the light-matter interaction: the energy shift of individual atomic levels and coherent population transfer between atomic eigenstates, revealing coherent superpositions. An intuitive formula is derived to treat both effects in a unifying framework, allowing one to identify and quantify the two processes in a single absorption spectrogram.

  3. Attosecond transient absorption of argon atoms in the vacuum ultraviolet region: line energy shifts versus coherent population transfer

    DOE PAGES

    Cao, Wei; Warrick, Erika R.; Neumark, Daniel M.; ...

    2016-01-18

    Using attosecond transient absorption, the dipole response of an argon atom in the vacuum ultraviolet (VUV) region is studied when an external electromagnetic field is present. An isolated attosecond VUV pulse populates Rydberg states lying 15 eV above the argon ground state. A synchronized few-cycle near infrared (NIR) pulse modifies the oscillating dipoles of argon impulsively, leading to alterations in the VUV absorption spectra. As the NIR pulse is delayed with respect to the VUV pulse, multiple features in the absorption profile emerge simultaneously including line broadening, sideband structure, sub-cycle fast modulations, and 5-10 fs slow modulations. These features indicatemore » the coexistence of two general processes of the light-matter interaction: the energy shift of individual atomic levels and coherent population transfer between atomic eigenstates, revealing coherent superpositions. Finally, an intuitive formula is derived to treat both effects in a unifying framework, allowing one to identify and quantify the two processes in a single absorption spectrogram.« less

  4. Diode Lasers and Practical Trace Analysis.

    ERIC Educational Resources Information Center

    Imasaka, Totaro; Nobuhiko, Ishibashi

    1990-01-01

    Applications of lasers to molecular absorption spectrometry, molecular fluorescence spectrometry, visible semiconductor fluorometry, atomic absorption spectrometry, and atomic fluorescence spectrometry are discussed. Details of the use of the frequency-doubled diode laser are provided. (CW)

  5. Method and apparatus for quantum information processing using entangled neutral-atom qubits

    DOEpatents

    Jau, Yuan Yu; Biedermann, Grant; Deutsch, Ivan

    2018-04-03

    A method for preparing an entangled quantum state of an atomic ensemble is provided. The method includes loading each atom of the atomic ensemble into a respective optical trap; placing each atom of the atomic ensemble into a same first atomic quantum state by impingement of pump radiation; approaching the atoms of the atomic ensemble to within a dipole-dipole interaction length of each other; Rydberg-dressing the atomic ensemble; during the Rydberg-dressing operation, exciting the atomic ensemble with a Raman pulse tuned to stimulate a ground-state hyperfine transition from the first atomic quantum state to a second atomic quantum state; and separating the atoms of the atomic ensemble by more than a dipole-dipole interaction length.

  6. A polarization converting device for an interfering enhanced CPT atomic clock.

    PubMed

    Wang, Kewei; Tian, Yuan; Yin, Yi; Wang, Yuanchao; Gu, Sihong

    2017-11-01

    With interfering enhanced coherent population trapping (CPT) signals, a CPT atomic clock with improved frequency stability performance can be realized. We explore an optical device that converts single-polarized bichromatic light to left and right circularly polarized superposed bichromatic light to generate interfering enhanced CPT resonance with atoms. We have experimentally studied a tabletop CPT atomic clock apparatus with a microfabricated 87 Rb atomic chip-scale cell, and the study results show that it is promising to realize a compact CPT atomic clock, even a chip-scale CPT atomic clock through microfabrication, with improved frequency stability performance.

  7. A polarization converting device for an interfering enhanced CPT atomic clock

    NASA Astrophysics Data System (ADS)

    Wang, Kewei; Tian, Yuan; Yin, Yi; Wang, Yuanchao; Gu, Sihong

    2017-11-01

    With interfering enhanced coherent population trapping (CPT) signals, a CPT atomic clock with improved frequency stability performance can be realized. We explore an optical device that converts single-polarized bichromatic light to left and right circularly polarized superposed bichromatic light to generate interfering enhanced CPT resonance with atoms. We have experimentally studied a tabletop CPT atomic clock apparatus with a microfabricated 87Rb atomic chip-scale cell, and the study results show that it is promising to realize a compact CPT atomic clock, even a chip-scale CPT atomic clock through microfabrication, with improved frequency stability performance.

  8. Modeling the Oxygen K Absorption in the Interstellar Medium: An XMM-Newton View of Sco X-1

    NASA Technical Reports Server (NTRS)

    Garcia, J.; Ramirez, J. M.; Kallman, T. R.; Witthoeft, M.; Bautista, M. A.; Mendoza, C.; Palmeri, P.; Quinet, P.

    2011-01-01

    We investigate the absorption structure of the oxygen in the interstellar medium by analyzing XMM-Newton observations of the low mass X-ray binary Sco X-1. We use simple models based on the O I atomic cross section from different sources to fit the data and evaluate the impact of the atomic data in the interpretation of astrophysical observations. We show that relatively small differences in the atomic calculations can yield spurious results. We also show that the most complete and accurate set of atomic cross sections successfully reproduce the observed data in the 21 - 24.5 Angstrom wavelength region of the spectrum. Our fits indicate that the absorption is mainly due to neutral gas with an ionization parameter of Epsilon = 10(exp -4) erg/sq cm, and an oxygen column density of N(sub O) approx. = 8-10 x 10(exp 17)/sq cm. Our models are able to reproduce both the K edge and the K(alpha) absorption line from O I, which are the two main features in this region. We find no conclusive evidence for absorption by other than atomic oxygen.

  9. Method and apparatus for simulating atomospheric absorption of solar energy due to water vapor and CO.sub.2

    DOEpatents

    Sopori, Bhushan L.

    1995-01-01

    A method and apparatus for improving the accuracy of the simulation of sunlight reaching the earth's surface includes a relatively small heated chamber having an optical inlet and an optical outlet, the chamber having a cavity that can be filled with a heated stream of CO.sub.2 and water vapor. A simulated beam comprising infrared and near infrared light can be directed through the chamber cavity containing the CO.sub.2 and water vapor, whereby the spectral characteristics of the beam are altered so that the output beam from the chamber contains wavelength bands that accurately replicate atmospheric absorption of solar energy due to atmospheric CO.sub.2 and moisture.

  10. Method and apparatus for simulating atmospheric absorption of solar energy due to water vapor and CO{sub 2}

    DOEpatents

    Sopori, B.L.

    1995-06-20

    A method and apparatus for improving the accuracy of the simulation of sunlight reaching the earth`s surface includes a relatively small heated chamber having an optical inlet and an optical outlet, the chamber having a cavity that can be filled with a heated stream of CO{sub 2} and water vapor. A simulated beam comprising infrared and near infrared light can be directed through the chamber cavity containing the CO{sub 2} and water vapor, whereby the spectral characteristics of the beam are altered so that the output beam from the chamber contains wavelength bands that accurately replicate atmospheric absorption of solar energy due to atmospheric CO{sub 2} and moisture. 8 figs.

  11. Resonance Ionization, Mass Spectrometry.

    ERIC Educational Resources Information Center

    Young, J. P.; And Others

    1989-01-01

    Discussed is an analytical technique that uses photons from lasers to resonantly excite an electron from some initial state of a gaseous atom through various excited states of the atom or molecule. Described are the apparatus, some analytical applications, and the precision and accuracy of the technique. Lists 26 references. (CW)

  12. Methods for analysis of selected metals in water by atomic absorption

    USGS Publications Warehouse

    Fishman, Marvin J.; Downs, Sanford C.

    1966-01-01

    This manual describes atomic-absorption-spectroscopy methods for determining calcium, copper, lithium, magnesium, manganese, potassium, sodium, strontium and zinc in atmospheric precipitation, fresh waters, and brines. The procedures are intended to be used by water quality laboratories of the Water Resources Division of the U.S. Geological Survey. Detailed procedures, calculations, and methods for the preparation of reagents are given for each element along with data on accuracy, precision, and sensitivity. Other topics discussed briefly are the principle of atomic absorption, instrumentation used, and special analytical techniques.

  13. Determination of palladium and platinum by atomic absorption

    USGS Publications Warehouse

    Schnepfe, M.M.; Grimaldi, F.S.

    1969-01-01

    Palladium and platinum are determined by atomic absorption after fire-assay concentration into a gold bead. The limit of determination is ~0??06 ppm in a 20-g sample. Serious depressive interelement interferences are removed by buffering the solutions with a mixture of cadmium and copper sulphates with cadmium and copper concentrations each at 0??5%. Substantial amounts of Ag, Al, Au, Bi, Ca, Co, Cr, Fe, Hg, K, La, Mg, Mn, Mo, Na, Ni, Pb, Te, Ti, V, Y, Zn, and the platinum metals do not interfere in the atomic-absorption determination. ?? 1969.

  14. Anomalous small-angle scattering as a way to solve the Babinet principle problem

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Boiko, M. E., E-mail: m.e.boiko@mail.ioffe.ru; Sharkov, M. D.; Boiko, A. M.

    2013-12-15

    X-ray absorption spectra (XAS) have been used to determine the absorption edges of atoms present in a sample under study. A series of small-angle X-ray scattering (SAXS) measurements using different monochromatic X-ray beams at different wavelengths near the absorption edges is performed to solve the Babinet principle problem. The sizes of clusters containing atoms determined by the method of XAS were defined in SAXS experiments. In contrast to differential X-ray porosimetry, anomalous SAXS makes it possible to determine sizes of clusters of different atomic compositions.

  15. Anomalous small-angle scattering as a way to solve the Babinet principle problem

    NASA Astrophysics Data System (ADS)

    Boiko, M. E.; Sharkov, M. D.; Boiko, A. M.; Bobyl, A. V.

    2013-12-01

    X-ray absorption spectra (XAS) have been used to determine the absorption edges of atoms present in a sample under study. A series of small-angle X-ray scattering (SAXS) measurements using different monochromatic X-ray beams at different wavelengths near the absorption edges is performed to solve the Babinet principle problem. The sizes of clusters containing atoms determined by the method of XAS were defined in SAXS experiments. In contrast to differential X-ray porosimetry, anomalous SAXS makes it possible to determine sizes of clusters of different atomic compositions.

  16. Enhanced multifunctional paint for detection of radiation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Farmer, Joseph C.; Moses, Edward Ira; Rubenchik, Alexander M.

    An enhanced multifunctional paint apparatus, systems, and methods for detecting radiation on a surface include providing scintillation particles; providing an enhance neutron absorptive material; providing a binder; combining the scintillation particles, the enhance neutron absorptive material, and the binder creating a multifunctional paint; applying the multifunctional paint to the surface; and monitoring the surface for detecting radiation.

  17. Mobile system for microwave removal of concrete surfaces

    DOEpatents

    White, Terry L.; Bigelow, Timothy S.; Schaich, Charles R.; Foster, Jr., Don

    1997-01-01

    A method and apparatus for the microwave removal of contaminated concrete surfaces. The apparatus comprises a housing adapted to pass over a support surface. The housing includes a waveguide for directing microwave energy to the surface at an angle maximizing absorption of microwave energy by the surface. The apparatus is further provided with a source of microwave energy operably associated with the waveguide, wherein the microwave energy has a frequency of between about 10.6 GHz and about 24 GHz and acts to remove the uppermost layer from the surface. The apparatus further includes a debris containment assembly comprising a vacuum assembly operably associated with the housing. The vacuum assembly is adapted to remove debris from the area adjacent the surface.

  18. Mobile system for microwave removal of concrete surfaces

    DOEpatents

    White, T.L.; Bigelow, T.S.; Schaich, C.R.; Foster, D. Jr.

    1997-06-03

    A method and apparatus are disclosed for the microwave removal of contaminated concrete surfaces. The apparatus comprises a housing adapted to pass over a support surface. The housing includes a waveguide for directing microwave energy to the surface at an angle maximizing absorption of microwave energy by the surface. The apparatus is further provided with a source of microwave energy operably associated with the waveguide, wherein the microwave energy has a frequency of between about 10.6 GHz and about 24 GHz and acts to remove the uppermost layer from the surface. The apparatus further includes a debris containment assembly comprising a vacuum assembly operably associated with the housing. The vacuum assembly is adapted to remove debris from the area adjacent the surface. 7 figs.

  19. Metal atomization spray nozzle

    DOEpatents

    Huxford, T.J.

    1993-11-16

    A spray nozzle for a magnetohydrodynamic atomization apparatus has a feed passage for molten metal and a pair of spray electrodes mounted in the feed passage. The electrodes, diverging surfaces which define a nozzle throat and diverge at an acute angle from the throat. Current passes through molten metal when fed through the throat which creates the Lorentz force necessary to provide atomization of the molten metal. 6 figures.

  20. Enhanced Reverse Saturable Absorption and Optical Limiting in Heavy-Atom Substituted Phthalocyanines

    NASA Technical Reports Server (NTRS)

    Perry, J. W.; Mansour, K.; Marder, S. R.; Alvarez, D., Jr.; Perry, K. J.; Choong, I.

    1994-01-01

    The reverse saturable absorption and optical limiting response of metal phthalocyaninies can be enhanced by using the heavy-atom effect. Phthalocyanines containing heavy metal atoms, such as In, Sn, and Pb show nearly a factor of two enhancement in the ratio of effective excited-state to ground-state absorption cross sections compared to those containing lighter atoms, such as Al and Si. In an f/8 optical geometry, homogeneous solutions of heavy metal phthalocyanines, at 30% linear transmission, limit 8-ns, 532-nm laser pulses to less than or equal to 3 (micro)J (the energy for 50% probability of eye damage) for incident pulses up to 800 (micro)J.

  1. Atomic Beam Scattering Methods to Study Overlayer Structures and H-Surface Interaction Relevant to Astrophysics

    NASA Astrophysics Data System (ADS)

    Lin, Jingsu

    In this thesis we present results of experimental methods for studying surface structures of ultra-thin films and describe a new apparatus to study the recombination of atomic hydrogen on well characterized low temperature surface using atomic and molecular beam methods. We have used atomic beam scattering (ABS) to characterize the growth of mercury and lead overlayers on Cu(001) surface. The structures of ordered phases have been identified using ABS and low-energy electron diffraction (LEED). A model to analyze diffraction data from these phases is presented. The new apparatus we are going to describe includes a high performance atomic hydrogen source using radio-frequency (RF) dissociation. The dissociation efficiency can be as high as 90% in the optimized pressure range. An atomic hydrogen beam line has been added to our ultra-high vacuum (UHV) scattering apparatus. We have also designed and constructed a low temperature sample manipulator for experiments at liquid helium temperatures. The manipulator has one degree of freedom of rotation and the capability of heating the sample to 700K and cooling down to 12K. The first sample studied was a single graphite surface. We have used a He beam to characterize the sample surface and to monitor deposition of H on the sample surface in real time. A series of "adsorption curves" have been obtained at different temperature and doses. We found that at temperatures below 16K, both H and H_2 have formed a partial layer on the surface. From adsorption curve, we deduce that the initial sticking coefficient for H is about 0.06 when surface at 16K. When the H beam is interrupted, the He specularly reflected beam recovers partially, indicating that hydrogen atoms desorb, while others remain on the surface. The residual coverage of H is estimated to be about 2% of a monolayer.

  2. Mini-Column Ion-Exchange Separation and Atomic Absorption Quantitation of Nickel, Cobalt, and Iron: An Undergraduate Quantitative Analysis Experiment.

    ERIC Educational Resources Information Center

    Anderson, James L.; And Others

    1980-01-01

    Presents an undergraduate quantitative analysis experiment, describing an atomic absorption quantitation scheme that is fast, sensitive and comparatively simple relative to other titration experiments. (CS)

  3. 40 CFR Appendix G to Part 50 - Reference Method for the Determination of Lead in Suspended Particulate Matter Collected From...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Absorption Spectroscopy.” Published by Interscience Company, New York, NY (1968). 5. Kirkbright, G. F., and Sargent, M., “Atomic Absorption and Fluorescence Spectroscopy.” Published by Academic Press, New York, NY... County, IL, by Atomic Absorption Spectroscopy.” Envir. Sci. and Tech., 3, 472-475 (1969). 7. “Proposed...

  4. Direct determination and speciation of mercury compounds in environmental and biological samples by carbon bed atomic absorption spectroscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Skelly, E.M.

    A method was developed for the direct determination of mercury in water and biological samples using a unique carbon bed atomizer for atomic absorption spectroscopy. The method avoided sources of error such as loss of volatile mercury during sample digestion and contamination of samples through added reagents by eliminating sample pretreatment steps. The design of the atomizer allowed use of the 184.9 nm mercury resonance line in the vacuum ultraviolet region, which increased sensitivity over the commonly used spin-forbidden 253.7 nm line. The carbon bed atomizer method was applied to a study of mercury concentrations in water, hair, sweat, urine,more » blood, breath and saliva samples from a non-occupationally exposed population. Data were collected on the average concentration, the range and distribution of mercury in the samples. Data were also collected illustrating individual variations in mercury concentrations with time. Concentrations of mercury found were significantly higher than values reported in the literature for a ''normal'' population. This is attributed to the increased accuracy gained by eliminating pretreatment steps and increasing atomization efficiency. Absorption traces were obtained for various solutions of pure and complexed mercury compounds. Absorption traces of biological fluids were also obtained. Differences were observed in the absorption-temperatures traces of various compounds. The utility of this technique for studying complexation was demonstrated.« less

  5. High enthalpy arc-heated plasma flow diagnostics by tunable diode laser absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Lin, Xin; Chen, Lianzhong; Zeng, Hui; Ou, Dongbin; Dong, Yonghui

    2017-05-01

    This paper reports the laser absorption measurements of atomic oxygen in the FD04 arc-heater at China Academy of Aerospace Aerodynamics (CAAA). An atomic oxygen absorption line at 777.19 nm is utilizied for detecting the population of electronically excited oxygen atom in an air plasma flow. A scanned-wavelength direct absorption mode is used in this study. The laser is scanned in wavelength across the absorption feature at a rate of 200 Hz. Under the assumption of thermal equilibrium, time-resolved temperature measurements are obtained on one line-of-sight in the arc-heater. The good agreement of the temperature inferred from the sonic throat method suggests the equilibrium assumption is valid. These results illustrate the feasibility of the diode laser sensors for flow parameters in high enthalpy arc-heated facilities.

  6. Mercury in Environmental and Biological Samples Using Online Combustion with Sequential Atomic Absorption and Fluorescence Measurements: A Direct Comparison of Two Fundamental Techniques in Spectrometry

    ERIC Educational Resources Information Center

    Cizdziel, James V.

    2011-01-01

    In this laboratory experiment, students quantitatively determine the concentration of an element (mercury) in an environmental or biological sample while comparing and contrasting the fundamental techniques of atomic absorption spectrometry (AAS) and atomic fluorescence spectrometry (AFS). A mercury analyzer based on sample combustion,…

  7. Methods for identification and verification using vacuum XRF system

    NASA Technical Reports Server (NTRS)

    Kaiser, Bruce (Inventor); Schramm, Fred (Inventor)

    2005-01-01

    Apparatus and methods in which one or more elemental taggants that are intrinsically located in an object are detected by x-ray fluorescence analysis under vacuum conditions to identify or verify the object's elemental content for elements with lower atomic numbers. By using x-ray fluorescence analysis, the apparatus and methods of the invention are simple and easy to use, as well as provide detection by a non line-of-sight method to establish the origin of objects, as well as their point of manufacture, authenticity, verification, security, and the presence of impurities. The invention is extremely advantageous because it provides the capability to measure lower atomic number elements in the field with a portable instrument.

  8. Atom chip microscopy: A novel probe for strongly correlated materials

    NASA Astrophysics Data System (ADS)

    Kasch, Brian; Naides, Matthew; Turner, Richard; Ray, Ushnish; Lev, Benjamin

    2010-03-01

    Atom chip technology---substrates supporting micron-sized current-carrying wires that create magnetic microtraps near surfaces for thermal or degenerate gases of neutral atoms---will enable single-shot, large area detection of magnetic flux below the 10-7 flux quantum level. By harnessing the extreme sensitivity of Bose-Einstein condensates (BECs) to external perturbations, cryogenic atom chips could provide a magnetic flux detection capability that surpasses all other techniques by a factor of 10^2--10^3. We describe the merits of atom chip microscopy, our Rb BEC and atom chip apparatus, and prospects for imaging strongly correlated condensed matter materials.

  9. Prospects for comparison of matter and antimatter gravitation with ALPHA-g.

    PubMed

    Bertsche, W A

    2018-03-28

    The ALPHA experiment has recently entered an expansion phase of its experimental programme, driven in part by the expected benefits of conducting experiments in the framework of the new AD + ELENA antiproton facility at CERN. With antihydrogen trapping now a routine operation in the ALPHA experiment, the collaboration is leading progress towards precision atomic measurements on trapped antihydrogen atoms, with the first excitation of the 1S-2S transition and the first measurement of the antihydrogen hyperfine spectrum (Ahmadi et al. 2017 Nature 541 , 506-510 (doi:10.1038/nature21040); Nature 548 , 66-69 (doi:10.1038/nature23446)). We are building on these successes to extend our physics programme to include a measurement of antimatter gravitation. We plan to expand a proof-of-principle method (Amole et al. 2013 Nat. Commun. 4 , 1785 (doi:10.1038/ncomms2787)), first demonstrated in the original ALPHA apparatus, and perform a precise measurement of antimatter gravitational acceleration with the aim of achieving a test of the weak equivalence principle at the 1% level. The design of this apparatus has drawn from a growing body of experience on the simulation and verification of antihydrogen orbits confined within magnetic-minimum atom traps. The new experiment, ALPHA-g, will be an additional atom-trapping apparatus located at the ALPHA experiment with the intention of measuring antihydrogen gravitation.This article is part of the Theo Murphy meeting issue 'Antiproton physics in the ELENA era'. © 2018 The Authors.

  10. Prospects for comparison of matter and antimatter gravitation with ALPHA-g

    NASA Astrophysics Data System (ADS)

    Bertsche, W. A.

    2018-03-01

    The ALPHA experiment has recently entered an expansion phase of its experimental programme, driven in part by the expected benefits of conducting experiments in the framework of the new AD + ELENA antiproton facility at CERN. With antihydrogen trapping now a routine operation in the ALPHA experiment, the collaboration is leading progress towards precision atomic measurements on trapped antihydrogen atoms, with the first excitation of the 1S-2S transition and the first measurement of the antihydrogen hyperfine spectrum (Ahmadi et al. 2017 Nature 541, 506-510 (doi:10.1038/nature21040); Nature 548, 66-69 (doi:10.1038/nature23446)). We are building on these successes to extend our physics programme to include a measurement of antimatter gravitation. We plan to expand a proof-of-principle method (Amole et al. 2013 Nat. Commun. 4, 1785 (doi:10.1038/ncomms2787)), first demonstrated in the original ALPHA apparatus, and perform a precise measurement of antimatter gravitational acceleration with the aim of achieving a test of the weak equivalence principle at the 1% level. The design of this apparatus has drawn from a growing body of experience on the simulation and verification of antihydrogen orbits confined within magnetic-minimum atom traps. The new experiment, ALPHA-g, will be an additional atom-trapping apparatus located at the ALPHA experiment with the intention of measuring antihydrogen gravitation. This article is part of the Theo Murphy meeting issue 'Antiproton physics in the ELENA era'.

  11. Prospects for comparison of matter and antimatter gravitation with ALPHA-g

    PubMed Central

    2018-01-01

    The ALPHA experiment has recently entered an expansion phase of its experimental programme, driven in part by the expected benefits of conducting experiments in the framework of the new AD + ELENA antiproton facility at CERN. With antihydrogen trapping now a routine operation in the ALPHA experiment, the collaboration is leading progress towards precision atomic measurements on trapped antihydrogen atoms, with the first excitation of the 1S–2S transition and the first measurement of the antihydrogen hyperfine spectrum (Ahmadi et al. 2017 Nature 541, 506–510 (doi:10.1038/nature21040); Nature 548, 66–69 (doi:10.1038/nature23446)). We are building on these successes to extend our physics programme to include a measurement of antimatter gravitation. We plan to expand a proof-of-principle method (Amole et al. 2013 Nat. Commun. 4, 1785 (doi:10.1038/ncomms2787)), first demonstrated in the original ALPHA apparatus, and perform a precise measurement of antimatter gravitational acceleration with the aim of achieving a test of the weak equivalence principle at the 1% level. The design of this apparatus has drawn from a growing body of experience on the simulation and verification of antihydrogen orbits confined within magnetic-minimum atom traps. The new experiment, ALPHA-g, will be an additional atom-trapping apparatus located at the ALPHA experiment with the intention of measuring antihydrogen gravitation. This article is part of the Theo Murphy meeting issue ‘Antiproton physics in the ELENA era’. PMID:29459415

  12. Atomic hydrogen storage method and apparatus

    NASA Technical Reports Server (NTRS)

    Woollam, J. A. (Inventor)

    1978-01-01

    Atomic hydrogen, for use as a fuel or as an explosive, is stored in the presence of a strong magnetic field in exfoliated layered compounds such as molybdenum disulfide or an elemental layer material such as graphite. The compound is maintained at liquid helium temperatures and the atomic hydrogen is collected on the surfaces of the layered compound which are exposed during delamination (exfoliation). The strong magnetic field and the low temperature combine to prevent the atoms of hydrogen from recombining to form molecules.

  13. Atomic hydrogen storage method and apparatus

    NASA Technical Reports Server (NTRS)

    Woollam, J. A. (Inventor)

    1980-01-01

    Atomic hydrogen, for use as a fuel or as an explosive, is stored in the presence of a strong magnetic field in exfoliated layered compounds such as molybdenum disulfide or an elemental layer material such as graphite. The compounds maintained at liquid helium temperatures and the atomic hydrogen is collected on the surfaces of the layered compound which are exposed during delamination (exfoliation). The strong magnetic field and the low temperature combine to prevent the atoms of hydrogen from recombining to form molecules.

  14. Optical state-of-charge monitor for batteries

    DOEpatents

    Weiss, Jonathan D.

    1999-01-01

    A method and apparatus for determining the instantaneous state-of-charge of a battery in which change in composition with discharge manifests itself as a change in optical absorption. In a lead-acid battery, the sensor comprises a fiber optic system with an absorption cell or, alternatively, an optical fiber woven into an absorbed-glass-mat battery. In a lithium-ion battery, the sensor comprises fiber optics for introducing light into the anode to monitor absorption when lithium ions are introduced.

  15. Method and apparatus for monitoring mercury emissions

    DOEpatents

    Durham, Michael D.; Schlager, Richard J.; Sappey, Andrew D.; Sagan, Francis J.; Marmaro, Roger W.; Wilson, Kevin G.

    1997-01-01

    A mercury monitoring device that continuously monitors the total mercury concentration in a gas. The device uses the same chamber for converting speciated mercury into elemental mercury and for measurement of the mercury in the chamber by radiation absorption techniques. The interior of the chamber is resistant to the absorption of speciated and elemental mercury at the operating temperature of the chamber.

  16. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    DOEpatents

    Phillips, Benjamin A.; Zawacki, Thomas S.

    1996-12-03

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium. A combination of weak and rich liquor working solution is used as the heat transfer medium.

  17. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    DOEpatents

    Phillips, B.A.; Zawacki, T.S.

    1998-07-21

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use, as the heat transfer medium, the working fluid of the absorption system taken from the generator at a location where the working fluid has a rich liquor concentration. 5 figs.

  18. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    DOEpatents

    Phillips, Benjamin A.; Zawacki, Thomas S.

    1998-07-21

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use, as the heat transfer medium, the working fluid of the absorption system taken from the generator at a location where the working fluid has a rich liquor concentration.

  19. Method and apparatus for monitoring mercury emissions

    DOEpatents

    Durham, M.D.; Schlager, R.J.; Sappey, A.D.; Sagan, F.J.; Marmaro, R.W.; Wilson, K.G.

    1997-10-21

    A mercury monitoring device that continuously monitors the total mercury concentration in a gas. The device uses the same chamber for converting speciated mercury into elemental mercury and for measurement of the mercury in the chamber by radiation absorption techniques. The interior of the chamber is resistant to the absorption of speciated and elemental mercury at the operating temperature of the chamber. 15 figs.

  20. Determination of cadmium in urine by extraction and flameless atomic-absorption spectrophotometry Comparison of urine from smokers and non-smokers of different sex and age.

    PubMed

    Jawaid, M; Lind, B; Elinder, C G

    1983-07-01

    A method is presented for determining cadmium in urine by nameless atomic-absorption spectrophotometry after extraction. The sample is dried, ashed in the presence of nitric acid, and then the residue is dissolved in hydrochloric acid. Cadmium is extracted as its tetrahexylammonium iodide complex into methyl isobutyl ketone. The organic phase is analysed for cadmium by atomic-absorption spectrophotometry with electrothermal atomization. The median urinary excretion of cadmium for smokers aged 50-64 has been found to be 0.7 and 0.75 mug l . for males and females respectively, the values for non-smokers being 0.25 and 0.4mug l .

  1. Method 200.12 - Determination of Trace Elements in Marine Waters by StabilizedTemperature Graphite Furnace Atomic Absorption

    EPA Science Inventory

    This method provides procedures for the determination of total recoverable elements by graphite furnace atomic absorption (GFAA) in marine waters, including estuarine, ocean and brines with salinities of up to 35 ppt.

  2. Procedure for rapid determination of nickel, cobalt, and chromium in airborne particulate samples

    NASA Technical Reports Server (NTRS)

    Davis, W. F.; Graab, J. W.

    1972-01-01

    A rapid, selective procedure for the determination of 1 to 20 micrograms of nickel, chromium, and cobalt in airborne particulates is described. The method utilizes the combined techniques of low temperature ashing and atomic absorption spectroscopy. The airborne particulates are collected on analytical filter paper. The filter papers are ashed, and the residues are dissolved in hydrochloric acid. Nickel, chromium, and cobalt are determined directly with good precision and accuracy by means of atomic absorption. The effects of flame type, burner height, slit width, and lamp current on the atomic absorption measurements are reported.

  3. Assessing the engagement, learning, and overall experience of students operating an atomic absorption spectrophotometer with remote access technology.

    PubMed

    Erasmus, Daniel J; Brewer, Sharon E; Cinel, Bruno

    2015-01-01

    The use of internet-based technologies in the teaching of laboratories has emerged as a promising education tool. This study evaluated the effectiveness of using remote access technology to operate an atomic absorption spectrophotometer in analyzing the iron content in a crude myoglobin extract. Sixty-two students were surveyed on their level of engagement, learning, and overall experience. Feedback from students suggests that the use of remote access technology is effective in teaching students the principles of chemical analysis by atomic absorption spectroscopy. © 2014 The International Union of Biochemistry and Molecular Biology.

  4. Methods and apparatuses for preparing a surface to have catalytic activity

    DOEpatents

    Cooks, Robert G [West Lafayette, IN; Peng, Wen-Ping [West Lafayette, IN; Ouyang, Zheng [West Lafayette, IN; Goodwin, Michael P [West Lafayette, IN

    2011-03-22

    The invention provides methods and apparatuses that utilize mass spectrometry for preparation of a surface to have catalytic activity through molecular soft-landing of mass selected ions. Mass spectrometry is used to generate combinations of atoms in a particular geometrical arrangement, and ion soft-landing selects this molecular entity or combination of entities and gently deposits the entity or combination intact onto a surface.

  5. Trace Element Analysis of Biological Samples.

    ERIC Educational Resources Information Center

    Veillon, Claude

    1986-01-01

    Reviews background of atomic absorption spectrometry techniques. Discusses problems encountered and precautions to be taken in determining trace elements in the parts-per-billion concentration range and below. Concentrates on determining chromium in biological samples by graphite furnace atomic absorption. Considers other elements, matrices, and…

  6. A high-pressure atomic force microscope for imaging in supercritical carbon dioxide

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lea, Alan S.; Higgins, Steven R.; Knauss, Kevin G.

    2011-04-26

    A high-pressure atomic force microscope (AFM) that enables in-situ, atomic scale measurements of topography of solid surfaces in contact with supercritical CO2 (scCO2) fluids has been developed. This apparatus overcomes the pressure limitations of the hydrothermal AFM and is designed to handle pressures up to 100 atm at temperatures up to ~ 350 K. A standard optically-based cantilever deflection detection system was chosen. When imaging in compressible supercritical fluids such as scCO2, precise control of pressure and temperature in the fluid cell is the primary technical challenge. Noise levels and imaging resolution depend on minimization of fluid density fluctuations thatmore » change the fluid refractive index and hence the laser path. We demonstrate with our apparatus in-situ atomic scale imaging of a calcite (CaCO3) mineral surface in scCO2; both single, monatomic steps and dynamic processes occurring on the (10¯14) surface are presented. This new AFM provides unprecedented in-situ access to interfacial phenomena at solid-fluid interfaces under pressure.« less

  7. Two-photon absorption laser-induced fluorescence of atomic oxygen in the afterglow of pulsed positive corona discharge

    NASA Astrophysics Data System (ADS)

    Ono, Ryo; Takezawa, Kei; Oda, Tetsuji

    2009-08-01

    Atomic oxygen is measured in the afterglow of pulsed positive corona discharge using time-resolved two-photon absorption laser-induced fluorescence. The discharge occurs in a 14 mm point-to-plane gap in dry air. After the discharge pulse, the atomic oxygen density decreases at a rate of 5×104 s-1. Simultaneously, ozone density increases at almost the same rate, where the ozone density is measured using laser absorption method. This agreement between the increasing rate of atomic oxygen and decreasing rate of ozone proves that ozone is mainly produced by the well-known three-body reaction, O+O2+M→O3+M. No other process for ozone production such as O2(v)+O2→O3+O is observed. The spatial distribution of atomic oxygen density is in agreement with that of the secondary streamer luminous intensity. This agreement indicates that atomic oxygen is mainly produced in the secondary streamer channels, not in the primary streamer channels.

  8. VUV absorption spectroscopy measurements of the role of fast neutral atoms in a high-power gap breakdown

    NASA Astrophysics Data System (ADS)

    Filuk, A. B.; Bailey, J. E.; Cuneo, M. E.; Lake, P. W.; Nash, T. J.; Noack, D. D.; Maron, Y.

    2000-12-01

    The maximum power achieved in a wide variety of high-power devices, including electron and ion diodes, z pinches, and microwave generators, is presently limited by anode-cathode gap breakdown. A frequently discussed hypothesis for this effect is ionization of fast neutral atoms injected throughout the anode-cathode gap during the power pulse. We describe a newly developed diagnostic tool that provides a direct test of this hypothesis. Time-resolved vacuum-ultraviolet absorption spectroscopy is used to directly probe fast neutral atoms with 1-mm spatial resolution in the 10-mm anode-cathode gap of the SABRE 5 MV, 1 TW applied-B ion diode. Absorption spectra collected during Ar RF glow discharges and with CO2 gas fills confirm the reliability of the diagnostic technique. Throughout the 50-100 ns ion diode pulses no measurable neutral absorption was seen, setting upper limits of (0.12-1.5)×1014 cm-3 for ground-state fast neutral atom densities of H, C, N, O, and F. The absence of molecular absorption bands also sets upper limits of (0.16-1.2)×1015 cm-3 for common simple molecules. These limits are low enough to rule out ionization of fast neutral atoms as a breakdown mechanism. Breakdown due to ionization of molecules is also found to be unlikely. This technique can now be applied to quantify the role of neutral atoms in other high-power devices.

  9. NARROW Na AND K ABSORPTION LINES TOWARD T TAURI STARS: TRACING THE ATOMIC ENVELOPE OF MOLECULAR CLOUDS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pascucci, I.; Simon, M. N.; Edwards, S.

    2015-11-20

    We present a detailed analysis of narrow Na i and K i absorption resonance lines toward nearly 40 T Tauri stars in Taurus with the goal of clarifying their origin. The Na i λ5889.95 line is detected toward all but one source, while the weaker K i λ7698.96 line is detected in about two-thirds of the sample. The similarity in their peak centroids and the significant positive correlation between their equivalent widths demonstrate that these transitions trace the same atomic gas. The absorption lines are present toward both disk and diskless young stellar objects, which excludes cold gas within themore » circumstellar disk as the absorbing material. A comparison of Na i and CO detections and peak centroids demonstrates that the atomic gas and molecular gas are not co-located, the atomic gas being more extended than the molecular gas. The width of the atomic lines corroborates this finding and points to atomic gas about an order of magnitude warmer than the molecular gas. The distribution of Na i radial velocities shows a clear spatial gradient along the length of the Taurus molecular cloud filaments. This suggests that absorption is associated with the Taurus molecular cloud. Assuming that the gradient is due to cloud rotation, the rotation of the atomic gas is consistent with differential galactic rotation, whereas the rotation of the molecular gas, although with the same rotation axis, is retrograde. Our analysis shows that narrow Na i and K i absorption resonance lines are useful tracers of the atomic envelope of molecular clouds. In line with recent findings from giant molecular clouds, our results demonstrate that the velocity fields of the atomic and molecular gas are misaligned. The angular momentum of a molecular cloud is not simply inherited from the rotating Galactic disk from which it formed but may be redistributed by cloud–cloud interactions.« less

  10. DETERMINATION OF TOTAL MERCURY IN FISH TISSUES USING PYROLYSIS ATOMIC ABSORPTION SPECTROMETRY WITH GOLD AMALGAMATION

    EPA Science Inventory

    A simple and rapid procedure for measuring total mercury in fish tissues is evaluated and
    compared with conventional techniques. Using an automated instrument incorporating combustion, preconcentration by amalgamation with gold, and atomic absorption spectrometry (AAS), mill...

  11. DETERMINING BERYLLIUM IN DRINKING WATER BY GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROSCOPY

    EPA Science Inventory

    A direct graphite furnace atomic absorption spectroscopy method for the analysis of beryllium in drinking water has been derived from a method for determining beryllium in urine. Ammonium phosphomolybdate and ascorbic acid were employed as matrix modifiers. The matrix modifiers s...

  12. The extreme wings of atomic emission and absorption lines. [in low pressure gases

    NASA Technical Reports Server (NTRS)

    Dalgarno, A.; Sando, K. M.

    1973-01-01

    Consideration of the extreme wings of atomic and molecular emission and absorption lines in low pressure gases. Classical and semiclassical results are compared with accurate quantal calculations of the self-broadening of Lyman-alpha in the hydrogen absorption spectrum that arises from quasimolecular transition. The results of classical, quantal, and semiclassical calculations of the absorption coefficient in the red wing are shown for temperatures of 500, 200, and 100 K. The semiclassical and quantal spectra agree well in shape at 500 K. Various other findings are discused.

  13. A comparative study of gamma-ray interaction and absorption in some building materials using Zeff-toolkit

    NASA Astrophysics Data System (ADS)

    Mann, Kulwinder Singh; Heer, Manmohan Singh; Rani, Asha

    2016-07-01

    The gamma-ray shielding behaviour of a material can be investigated by determining its various interaction and energy-absorption parameters (such as mass attenuation coefficients, mass energy absorption coefficients, and corresponding effective atomic numbers and electron densities). Literature review indicates that the effective atomic number (Zeff) has been used as extensive parameters for evaluating the effects and defect in the chosen materials caused by ionising radiations (X-rays and gamma-rays). A computer program (Zeff-toolkit) has been designed for obtaining the mean value of effective atomic number calculated by three different methods. A good agreement between the results obtained with Zeff-toolkit, Auto_Zeff software and experimentally measured values of Zeff has been observed. Although the Zeff-toolkit is capable of computing effective atomic numbers for both photon interaction (Zeff,PI) and energy absorption (Zeff,En) using three methods in each. No similar computer program is available in the literature which simultaneously computes these parameters simultaneously. The computed parameters have been compared and correlated in the wide energy range (0.001-20 MeV) for 10 commonly used building materials. The prominent variations in these parameters with gamma-ray photon energy have been observed due to the dominance of various absorption and scattering phenomena. The mean values of two effective atomic numbers (Zeff,PI and Zeff,En) are equivalent at energies below 0.002 MeV and above 0.3 MeV, indicating the dominance of gamma-ray absorption (photoelectric and pair production) over scattering (Compton) at these energies. Conversely in the energy range 0.002-0.3 MeV, the Compton scattering of gamma-rays dominates the absorption. From the 10 chosen samples of building materials, 2 soils showed better shielding behaviour than did other 8 materials.

  14. Continuous microwave regeneration apparatus for absorption media

    DOEpatents

    Smith, Douglas D.

    1999-01-01

    A method and apparatus for continuously drying and regenerating ceramic beads for use in process gas moisture drying operations such as glove boxes. A microwave energy source is coupled to a process chamber to internally heat the ceramic beads and vaporize moisture contained therein. In a preferred embodiment, the moisture laden ceramic beads are conveyed toward the microwave source by a screw mechanism. The regenerated beads flow down outside of the screw mechanism and are available to absorb additional moisture.

  15. Disentangling atomic-layer-specific x-ray absorption spectra by Auger electron diffraction spectroscopy

    NASA Astrophysics Data System (ADS)

    Matsui, Fumihiko; Matsushita, Tomohiro; Kato, Yukako; Hashimoto, Mie; Daimon, Hiroshi

    2009-11-01

    In order to investigate the electronic and magnetic structures of each atomic layer at subsurface, we have proposed a new method, Auger electron diffraction spectroscopy, which is the combination of x-ray absorption spectroscopy (XAS) and Auger electron diffraction (AED) techniques. We have measured a series of Ni LMM AED patterns of the Ni film grown on Cu(001) surface for various thicknesses. Then we deduced a set of atomic-layer-specific AED patterns in a numerical way. Furthermore, we developed an algorithm to disentangle XANES spectra from different atomic layers using these atomic-layer-specific AED patterns. Surface and subsurface core level shift were determined for each atomic layer.

  16. Atomic-absorption determination of rhodium in chromite concentrates

    USGS Publications Warehouse

    Schnepfe, M.M.; Grimaldi, F.S.

    1969-01-01

    Rhodium is determined in chromite concentrates by atomic absorption after concentration either by co-precipitation with tellurium formed by the reduction of tellurite with tin(II) chloride or by fire assay into a gold bead. Interelement interferences in the atomic-absorption determination are removed by buffering the solutions with lanthanum sulphate (lanthanum concentration 1%). Substantial amounts of Ag, Al, Au, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ho, Hg, K, La, Mg, Mn, Mo, Na, Ni, Pb, Te, Ti, V, Y, Zn and platinum metals can be tolerated. A lower limit of approximately 0.07 ppm Rh can be determined in a 3-g sample. ?? 1969.

  17. Atomic Absorption Spectroscopy. The Present and the Future.

    ERIC Educational Resources Information Center

    Slavin, Walter

    1982-01-01

    The status of current techniques and methods of atomic absorption (AA) spectroscopy (flame, hybrid, and furnace AA) is discussed, including limitations. Technological opportunities and how they may be used in AA are also discussed, focusing on automation, microprocessors, continuum AA, hybrid analyses, and others. (Author/JN)

  18. Tunable Diode Laser Atomic Absorption Spectroscopy for Detection of Potassium under Optically Thick Conditions.

    PubMed

    Qu, Zhechao; Steinvall, Erik; Ghorbani, Ramin; Schmidt, Florian M

    2016-04-05

    Potassium (K) is an important element related to ash and fine-particle formation in biomass combustion processes. In situ measurements of gaseous atomic potassium, K(g), using robust optical absorption techniques can provide valuable insight into the K chemistry. However, for typical parts per billion K(g) concentrations in biomass flames and reactor gases, the product of atomic line strength and absorption path length can give rise to such high absorbance that the sample becomes opaque around the transition line center. We present a tunable diode laser atomic absorption spectroscopy (TDLAAS) methodology that enables accurate, calibration-free species quantification even under optically thick conditions, given that Beer-Lambert's law is valid. Analyte concentration and collisional line shape broadening are simultaneously determined by a least-squares fit of simulated to measured absorption profiles. Method validation measurements of K(g) concentrations in saturated potassium hydroxide vapor in the temperature range 950-1200 K showed excellent agreement with equilibrium calculations, and a dynamic range from 40 pptv cm to 40 ppmv cm. The applicability of the compact TDLAAS sensor is demonstrated by real-time detection of K(g) concentrations close to biomass pellets during atmospheric combustion in a laboratory reactor.

  19. [Development of an experimental apparatus for energy calibration of a CdTe detector by means of diagnostic X-ray equipment].

    PubMed

    Fukuda, Ikuma; Hayashi, Hiroaki; Takegami, Kazuki; Konishi, Yuki

    2013-09-01

    Diagnostic X-ray equipment was used to develop an experimental apparatus for calibrating a CdTe detector. Powder-type samples were irradiated with collimated X-rays. On excitation of the atoms, characteristic X-rays were emitted. We prepared Nb2O5, SnO2, La2O3, Gd2O3, and WO3 metal oxide samples. Experiments using the diagnostic X-ray equipment were carried out to verify the practicality of our apparatus. First, we verified that the collimators involving the apparatus worked well. Second, the X-ray spectra were measured using the prepared samples. Finally, we analyzed the spectra, which indicated that the energy calibration curve had been obtained at an accuracy of ±0.06 keV. The developed apparatus could be used conveniently, suggesting it to be useful for the practical training of beginners and researchers.

  20. Analysis of Dithiocarbamate Fungicides in Vegetable Matrices Using HPLC-UV Followed by Atomic Absorption Spectrometry.

    PubMed

    Al-Alam, Josephine; Bom, Laura; Chbani, Asma; Fajloun, Ziad; Millet, Maurice

    2017-04-01

    A simple method combining ion-pair methylation, high-performance liquid chromatography (HPLC) analysis with detection at 272 nm and atomic absorption spectrometry was developed in order to determine 10 dithiocarbamate fungicides (Dazomet, Metam-sodium, Ferbam, Ziram, Zineb, Maneb, Mancozeb, Metiram, Nabam and Propineb) and distinguish ethylenbisdithiocarbamates (EBDTCs) Zineb, Maneb and Mancozeb in diverse matrices. This method associates reverse phase analysis by HPLC analysis with detection at 272 nm, with atomic absorption spectrometry in order to distinguish, with the same extraction protocol, Maneb, Mancozeb and Zineb. The limits of detection (0.4, 0.8, 0.5, 1.25 and 1.97) and quantification (1.18, 2.5, 1.52, 4.2 and 6.52) calculated in injected nanogram, respectively, for Dazomet, Metam-Na, dimethyldithiocarbamates (DMDTCs), EBDTCs and propylenebisdithiocarbamates (PBDTCs) justify the sensitivity of the method used. The coefficients of determination R2 were 0.9985, 0.9978, 0.9949, 0.988 and 0.9794, respectively, for Dazomet, Metam-Na, DMDTCs, EBDTCs and PBDTCs, and the recovery from fortified apple and leek samples was above 90%. Results obtained with the atomic absorption method in comparison with spectrophotometric analysis focus on the importance of the atomic absorption as a complementary specific method for the distinction between different EBDTCs fungicides. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Middle School Science Notes

    ERIC Educational Resources Information Center

    School Science Review, 1976

    1976-01-01

    Describes a lighted demonstration apparatus for representing the distribution of electrons, protons and neutrons in an atom. Also includes experiments with ice, forces, microscopes, spectra, and geological modeling. (CS)

  2. Coherent optical transients observed in rubidium atomic line filtered Doppler velocimetry experiments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fajardo, Mario E., E-mail: mario.fajardo@eglin.af.mil; Molek, Christopher D.; Vesely, Annamaria L.

    2015-10-14

    We report the first successful results from our novel Rubidium Atomic Line Filtered (RALF) Doppler velocimetry apparatus, along with unanticipated oscillatory signals due to coherent optical transients generated within pure Rb vapor cells. RALF is a high-velocity and high-acceleration extension of the well-known Doppler Global Velocimetry (DGV) technique for constructing multi-dimensional flow velocity vector maps in aerodynamics experiments [H. Komine, U.S. Patent No. 4,919,536 (24 April 1990)]. RALF exploits the frequency dependence of pressure-broadened Rb atom optical absorptions in a heated Rb/N{sub 2} gas cell to encode the Doppler shift of reflected near-resonant (λ{sub 0} ≈ 780.24 nm) laser light onto the intensitymore » transmitted by the cell. The present RALF apparatus combines fiber optic and free-space components and was built to determine suitable operating conditions and performance parameters for the Rb/N{sub 2} gas cells. It yields single-spot velocities of thin laser-driven-flyer test surfaces and incorporates a simultaneous Photonic Doppler Velocimetry (PDV) channel [Strand et al., Rev. Sci. Instrum. 77, 083108 (2006)] for validation of the RALF results, which we demonstrate here over the v = 0 to 1 km/s range. Both RALF and DGV presume the vapor cells to be simple Beer's Law optical absorbers, so we were quite surprised to observe oscillatory signals in experiments employing low pressure pure Rb vapor cells. We interpret these oscillations as interference between the Doppler shifted reflected light and the Free Induction Decay (FID) coherent optical transient produced within the pure Rb cells at the original laser frequency; this is confirmed by direct comparison of the PDV and FID signals. We attribute the different behaviors of the Rb/N{sub 2} vs. Rb gas cells to efficient dephasing of the atomic/optical coherences by Rb-N{sub 2} collisions. The minimum necessary N{sub 2} buffer gas density ≈0.3 amagat translates into a smallest useful velocity range of 0 to 2 km/s, which can readily be extended to cover the 0 to 10 km/s range, and beyond. The recognition that coherent optical transients can be produced within low pressure vapor cells during velocimetry experiments may offer new insights into some quantitative discrepancies reported in earlier DGV studies. Future plans include “line-RALF” experiments with streak camera detection, and two-dimensional surface velocity mapping using pulsed laser illumination and/or gated intensified CCD camera detection.« less

  3. Fast all-optical switch

    NASA Technical Reports Server (NTRS)

    Shay, Thomas M. (Inventor); Poliakov, Evgeni Y. (Inventor); Hazzard, David A. (Inventor)

    2001-01-01

    An apparatus and method wherein polarization rotation in alkali vapors or other mediums is used for all-optical switching and digital logic and where the rate of operation is proportional to the amplitude of the pump field. High rates of speed are accomplished by Rabi flopping of the atomic states using a continuously operating monochromatic atomic beam as the pump.

  4. Methods and apparatus of spatially resolved electroluminescence of operating organic light-emitting diodes using conductive atomic force microscopy

    NASA Technical Reports Server (NTRS)

    Hersam, Mark C. (Inventor); Pingree, Liam S. C. (Inventor)

    2008-01-01

    A conductive atomic force microscopy (cAFM) technique which can concurrently monitor topography, charge transport, and electroluminescence with nanometer spatial resolution. This cAFM approach is particularly well suited for probing the electroluminescent response characteristics of operating organic light-emitting diodes (OLEDs) over short length scales.

  5. Two-photon-excited fluorescence spectroscopy of atomic fluorine at 170 nm

    NASA Technical Reports Server (NTRS)

    Herring, G. C.; Dyer, Mark J.; Jusinski, Leonard E.; Bischel, William K.

    1988-01-01

    Two-photon-excited fluorescence spectroscopy of atomic fluorine is reported. A doubled dye laser at 286-nm is Raman shifted in H2 to 170 nm (sixth anti-Stokes order) to excite ground-state 2P(0)J fluorine atoms to the 2D(0)J level. The fluorine atoms are detected by one of two methods: observing the fluorescence decay to the 2PJ level or observing F(+) production through the absorption of an additional photon by the excited atoms. Relative two-photon absorption cross sections to and the radiative lifetimes of the 2D(0)J states are measured.

  6. Atomic and Molecular Gas Phase Spectrometry.

    DTIC Science & Technology

    1983-09-30

    between the thermometric levels, k is the Boltzmann constant (k = 0.695 cm-I K-1 ), Aik (s- 1) is the transition probability for spontaneous emission from...monitoring of the atomic absorption of M; information about the reaction processes were deduced from the shapes of the titration curves; (5) measure- ment of...Changes During Titration Based Upon The Releasing Effect Atomic Absorption Spectroscopy," D. Stojanovic and J.D. Winefordner, Anal Chim. Acta, 114, 295

  7. Polarization Imaging Apparatus

    NASA Technical Reports Server (NTRS)

    Zou, Yingyin K.; Chen, Qiushui

    2010-01-01

    A polarization imaging apparatus has shown promise as a prototype of instruments for medical imaging with contrast greater than that achievable by use of non-polarized light. The underlying principles of design and operation are derived from observations that light interacts with tissue ultrastructures that affect reflectance, scattering, absorption, and polarization of light. The apparatus utilizes high-speed electro-optical components for generating light properties and acquiring polarization images through aligned polarizers. These components include phase retarders made of OptoCeramic (registered TradeMark) material - a ceramic that has a high electro-optical coefficient. The apparatus includes a computer running a program that implements a novel algorithm for controlling the phase retarders, capturing image data, and computing the Stokes polarization images. Potential applications include imaging of superficial cancers and other skin lesions, early detection of diseased cells, and microscopic analysis of tissues. The high imaging speed of this apparatus could be beneficial for observing live cells or tissues, and could enable rapid identification of moving targets in astronomy and national defense. The apparatus could also be used as an analysis tool in material research and industrial processing.

  8. The Use of an Air-Natural Gas Flame in Atomic Absorption.

    ERIC Educational Resources Information Center

    Melucci, Robert C.

    1983-01-01

    Points out that excellent results are obtained using an air-natural gas flame in atomic absorption experiments rather than using an air-acetylene flame. Good results are obtained for alkali metals, copper, cadmium, and zinc but not for the alkaline earths since they form refractory oxides. (Author/JN)

  9. COMPREHENSIVE ANALYSIS OF BIOLOGICALLY RELEVANT ARSENICALS BY PH-SELECTIVE HYDRIDE GENERATION-ATOMIC ABSORPTION SPECTROMETRY

    EPA Science Inventory


    A method based on pH-selective generation and separation of arsines is commonly used for analysis of inorganic, methylated, and dimethylated trivalent and pentavalent arsenicals by hydride generation-atomic absorption spectrometry (HG-AAS). We have optimized this method to pe...

  10. [Atomic absorption in mercury determination by "Julia-2" analyzer and urine mercury level in children of Moscow suburbs].

    PubMed

    Pavlovskaia, N A; Vagina, E N; Stepanova, E V

    2000-01-01

    The authors report on atomic absorption method determining mercury in urine. Being sensitive, with lower determination threshold of 10 nmole/l and correctness of 95.5%, the method was tested on children living in two districts of Moscow suburb.

  11. VUV absorption spectroscopy measurements of the role of fast neutral atoms in a high-power gap breakdown

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Filuk, A. B.; Bailey, J. E.; Cuneo, M. E.

    The maximum power achieved in a wide variety of high-power devices, including electron and ion diodes, z pinches, and microwave generators, is presently limited by anode-cathode gap breakdown. A frequently discussed hypothesis for this effect is ionization of fast neutral atoms injected throughout the anode-cathode gap during the power pulse. We describe a newly developed diagnostic tool that provides a direct test of this hypothesis. Time-resolved vacuum-ultraviolet absorption spectroscopy is used to directly probe fast neutral atoms with 1-mm spatial resolution in the 10-mm anode-cathode gap of the SABRE 5 MV, 1 TW applied-B ion diode. Absorption spectra collected duringmore » Ar RF glow discharges and with CO{sub 2} gas fills confirm the reliability of the diagnostic technique. Throughout the 50--100 ns ion diode pulses no measurable neutral absorption was seen, setting upper limits of (0.12--1.5)x10{sup 14}cm{sup -3} for ground-state fast neutral atom densities of H, C, N, O, and F. The absence of molecular absorption bands also sets upper limits of (0.16--1.2)x10{sup 15}cm{sup -3} for common simple molecules. These limits are low enough to rule out ionization of fast neutral atoms as a breakdown mechanism. Breakdown due to ionization of molecules is also found to be unlikely. This technique can now be applied to quantify the role of neutral atoms in other high-power devices.« less

  12. Method and apparatus for determination of temperature, neutron absorption cross section and neutron moderating power

    DOEpatents

    Vagelatos, Nicholas; Steinman, Donald K.; John, Joseph; Young, Jack C.

    1981-01-01

    A nuclear method and apparatus determines the temperature of a medium by injecting fast neutrons into the medium and detecting returning slow neutrons in three first energy ranges by producing three respective detection signals. The detection signals are combined to produce three derived indicia each systematically related to the population of slow neutrons returning from the medium in a respective one of three second energy ranges, specifically exclusively epithermal neutrons, exclusively substantially all thermal neutrons and exclusively a portion of the thermal neutron spectrum. The derived indicia are compared with calibration indicia similarly systematically related to the population of slow neutrons in the same three second energy ranges returning from similarly irradiated calibration media for which the relationships temperature, neutron absorption cross section and neutron moderating power to such calibration indicia are known. The comparison indicates the temperature at which the calibration indicia correspond to the derived indicia and consequently the temperature of the medium. The neutron absorption cross section and moderating power of the medium can be identified at the same time.

  13. A single-sweep, nanosecond time resolution laser temperature-jump apparatus

    NASA Astrophysics Data System (ADS)

    Ballew, R. M.; Sabelko, J.; Reiner, C.; Gruebele, M.

    1996-10-01

    We describe a fast temperature-jump (T-jump) apparatus capable of acquiring kinetic relaxation transients via real-time fluorescence detection over a time interval from nanoseconds to milliseconds in a single sweep. The method is suitable for aqueous solutions, relying upon the direct absorption of laser light by the bulk water. This obviates the need for additives (serving as optical or conductive heaters) that may interact with the sample under investigation. The longitudinal temperature profile is made uniform by counterpropagating heating pulses. Dead time is limited to one period of the probe laser (16 ns). The apparatus response is tested with aqueous tryptophan and the diffusion-controlled dimerization of proflavine.

  14. Removal of Biologically Active Organic Contaminants using Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor); Banks, Michael A. (Inventor); Banks, Eric B. (Inventor)

    2003-01-01

    Biomedical devices that are to come into contact with living tissue, such as prosthetic and other implants for the human body and the containers used to store and transport them, are together cleaned of non-living, but biologically active organic materials, including endotoxins such as lipopolysaccharides, and assembled into a hermetically sealed package without recontamination. This is achieved by cleaning both the device and package components together in an apparatus, which includes a hermetically sealed chamber, in which they are contacted with atomic oxygen which biocleans them, by oxidizing the biologically active organic materials. The apparatus also includes means for manipulating the device and container and hermetically sealing the cleaned device into the cleaned container to form the package. A calibrated witness coupon visually indicates whether or not the device and container have received enough exposure to the atomic oxygen to have removed the organic materials from their surfaces. Gamma radiation is then used to sterilize the device in the sealed container.

  15. Improved Apparatus to Study Matter-Wave Quantum Optics in a Sodium Spinor Bose-Einstein Condensate

    NASA Astrophysics Data System (ADS)

    Zhong, Shan; Bhagat, Anita; Zhang, Qimin; Schwettmann, Arne

    2017-04-01

    We present and characterize our recently improved experimental apparatus for studying matter-wave quantum optics in spin space in ultracold sodium gases. Improvements include our recent addition of a 3D-printed Helmholtz coil frame for field stabilization and a crossed optical dipole trap. Spin-exchange collisions in the F = 1 spinor Bose-Einstein condensate can be precisely controlled by microwave dressing, and generate pairs of entangled atoms with magnetic quantum numbers mF = + 1 and mF = - 1 from pairs of mF = 0 atoms. Spin squeezing generated by the collisions can reduce the noise of population measurements below the shot noise limit. Versatile microwave pulse sequences will be used to implement an interferometer, a phase-sensitive amplifier and other devices with sub-shot noise performance. With an added ion detector to detect Rydberg atoms via pulse-field ionization, we later plan to study the effect of Rydberg excitations on the spin evolution of the ultracold gas.

  16. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: probing atomic structure in situ.

    PubMed

    Wang, Hsiu-Wen; Fanelli, Victor R; Reiche, Helmut M; Larson, Eric; Taylor, Mark A; Xu, Hongwu; Zhu, Jinlong; Siewenie, Joan; Page, Katharine

    2014-12-01

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO2 measurements. The new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO2 sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H2 and natural gas uptake/storage.

  17. Methods, systems, and apparatus for storage, transfer and/or control of information via matter wave dynamics

    NASA Technical Reports Server (NTRS)

    Vestergaard Hau, Lene (Inventor)

    2012-01-01

    Methods, systems and apparatus for generating atomic traps, and for storing, controlling and transferring information between first and second spatially separated phase-coherent objects, or using a single phase-coherent object. For plural objects, both phase-coherent objects have a macroscopic occupation of a particular quantum state by identical bosons or identical BCS-paired fermions. The information may be optical information, and the phase-coherent object(s) may be Bose-Einstein condensates, superfluids, or superconductors. The information is stored in the first phase-coherent object at a first storage time and recovered from the second phase-coherent object, or the same first phase-coherent object, at a second revival time. In one example, an integrated silicon wafer-based optical buffer includes an electrolytic atom source to provide the phase-coherent object(s), a nanoscale atomic trap for the phase-coherent object(s), and semiconductor-based optical sources to cool the phase-coherent object(s) and provide coupling fields for storage and transfer of optical information.

  18. Confocal absorption spectral imaging of MoS2: optical transitions depending on the atomic thickness of intrinsic and chemically doped MoS2.

    PubMed

    Dhakal, Krishna P; Duong, Dinh Loc; Lee, Jubok; Nam, Honggi; Kim, Minsu; Kan, Min; Lee, Young Hee; Kim, Jeongyong

    2014-11-07

    We performed a nanoscale confocal absorption spectral imaging to obtain the full absorption spectra (over the range 1.5-3.2 eV) within regions having different numbers of layers and studied the variation of optical transition depending on the atomic thickness of the MoS2 film. Three distinct absorption bands corresponding to A and B excitons and a high-energy background (BG) peak at 2.84 eV displayed a gradual redshift as the MoS2 film thickness increased from the monolayer, to the bilayer, to the bulk MoS2 and this shift was attributed to the reduction of the gap energy in the Brillouin zone at the K-point as the atomic thickness increased. We also performed n-type chemical doping of MoS2 films using reduced benzyl viologen (BV) and the confocal absorption spectra modified by the doping showed a strong dependence on the atomic thickness: A and B exciton peaks were greatly quenched in the monolayer MoS2 while much less effect was shown in larger thickness and the BG peak either showed very small quenching for 1 L MoS2 or remained constant for larger thicknesses. Our results indicate that confocal absorption spectral imaging can provide comprehensive information on optical transitions of microscopic size intrinsic and doped two-dimensional layered materials.

  19. Method and apparatus for optoacoustic spectroscopy

    DOEpatents

    Amer, Nabil M.

    1979-01-01

    A method and apparatus that significantly increases the sensitivity and flexibility of laser optoacoustic spectroscopy, with reduced size. With the method, it no longer is necessary to limit the use of laser optoacoustic spectroscopy to species whose absorption must match available laser radiation. Instead, "doping" with a relatively small amount of an optically absorbing gas yields optoacoustic signatures of nonabsorbing materials (gases, liquids, solids, and aerosols), thus significantly increasing the sensitivity and flexibility of optoacoustic spectroscopy. Several applications of this method are demonstated and/or suggested.

  20. Ambient methods and apparatus for rapid laser trace constituent analysis

    DOEpatents

    Snyder, Stuart C.; Partin, Judy K.; Grandy, Jon D.; Jeffery, Charles L.

    2002-01-01

    A method and apparatus are disclosed for measuring trace amounts of constituents in samples by using laser induced breakdown spectroscopy and laser induced fluorescence under ambient conditions. The laser induced fluorescence is performed at a selected wavelength corresponding to an absorption state of a selected trace constituent. The intensity value of the emission decay signal which is generated by the trace constituent is compared to calibrated emission intensity decay values to determine the amount of trace constituent present.

  1. Ultraviolet absorption: Experiment MA-059. [measurement of atmospheric species concentrations

    NASA Technical Reports Server (NTRS)

    Donahue, T. M.; Hudson, R. D.; Rawlins, W. T.; Anderson, J.; Kaufman, F.; Mcelroy, M. B.

    1977-01-01

    A technique devised to permit the measurement of atmospheric species concentrations is described. This technique involves the application of atomic absorption spectroscopy and the quantitative observation of resonance fluorescence in which atomic or molecular species scatter resonance radiation from a light source into a detector. A beam of atomic oxygen and atomic nitrogen resonance radiation, strong unabsorbable oxygen and nitrogen radiation, and visual radiation was sent from Apollo to Soyuz. The density of atomic oxygen and atomic nitrogen between the two spacecraft was measured by observing the amount of resonance radiation absorbed when the line joining Apollo and Soyuz was perpendicular to their velocity with respect to the ambient atmosphere. Results of postflight analysis of the resonance fluorescence data are discussed.

  2. Method and apparatus for the gas phase decontamination of chemical and biological agents

    DOEpatents

    O'Neill, Hugh J.; Brubaker, Kenneth L.

    2003-10-07

    An apparatus and method for decontaminating chemical and biological agents using the reactive properties of both the single atomic oxygen and the hydroxyl radical for the decontamination of chemical and biological agents. The apparatus is self contained and portable and allows for the application of gas reactants directly at the required decontamination point. The system provides for the use of ultraviolet light of a specific spectral range to photolytically break down ozone into molecular oxygen and hydroxyl radicals where some of the molecular oxygen is in the first excited state. The excited molecular oxygen will combine with water vapor to produce two hydroxyl radicals.

  3. Flame-Sprayed Y2O3 Films with Metal-EDTA Complex Using Various Cooling Agents

    NASA Astrophysics Data System (ADS)

    Komatsu, Keiji; Toyama, Ayumu; Sekiya, Tetsuo; Shirai, Tomoyuki; Nakamura, Atsushi; Toda, Ikumi; Ohshio, Shigeo; Muramatsu, Hiroyuki; Saitoh, Hidetoshi

    2017-01-01

    In this study, yttrium oxide (Y2O3) films were synthesized from a metal-ethylenediaminetetraacetic (metal-EDTA) complex by employing a H2-O2 combustion flame. A rotation apparatus and various cooling agents (compressed air, liquid nitrogen, and atomized purified water) were used during the synthesis to control the thermal history during film deposition. An EDTA·Y·H complex was prepared and used as the staring material for the synthesis of Y2O3 films with a flame-spraying apparatus. Although thermally extreme environments were employed during the synthesis, all of the obtained Y2O3 films showed only a few cracks and minor peeling in their microstructures. For instance, the Y2O3 film synthesized using the rotation apparatus with water atomization units exhibited a porosity of 22.8%. The maximum film's temperature after deposition was 453 °C owing to the high heat of evaporation of water. Cooling effects of substrate by various cooling units for solidification was dominated to heat of vaporization, not to unit's temperatures.

  4. Beyond the single-atom response in absorption line shapes: probing a dense, laser-dressed helium gas with attosecond pulse trains.

    PubMed

    Liao, Chen-Ting; Sandhu, Arvinder; Camp, Seth; Schafer, Kenneth J; Gaarde, Mette B

    2015-04-10

    We investigate the absorption line shapes of laser-dressed atoms beyond the single-atom response, by using extreme ultraviolet (XUV) attosecond pulse trains to probe an optically thick helium target under the influence of a strong infrared (IR) field. We study the interplay between the IR-induced phase shift of the microscopic time-dependent dipole moment and the resonant-propagation-induced reshaping of the macroscopic XUV pulse. Our experimental and theoretical results show that as the optical depth increases, this interplay leads initially to a broadening of the IR-modified line shape, and subsequently, to the appearance of new, narrow features in the absorption line.

  5. Determination of the atomic density of rubidium-87

    NASA Astrophysics Data System (ADS)

    Zhao, Meng; Zhang, Kai; Chen, Li-Qing

    2015-09-01

    Atomic density is a basic and important parameter in quantum optics, nonlinear optics, and precision measurement. In the past few decades, several methods have been used to measure atomic density, such as thermionic effect, optical absorption, and resonance fluorescence. The main error of these experiments stemmed from depopulation of the energy level, self-absorption, and the broad bandwidth of the laser. Here we demonstrate the atomic density of 87Rb vapor in paraffin coated cell between 297 K and 334 K mainly using fluorescence measurement. Optical pumping, anti-relaxation coating, and absorption compensation approaches are used to decrease measurement error. These measurement methods are suitable for vapor temperature at dozens of degrees. The fitting function for the experimental data of 87Rb atomic density is given. Project supported by the Natural Science Foundation of China (Grant Nos. 11274118 and 11474095), the Innovation Program of Shanghai Municipal Education Commission of China (Grant No. 13ZZ036), and the Fundamental Research Funds for the Central Universities of China.

  6. Efficient accesses of data structures using processing near memory

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jayasena, Nuwan S.; Zhang, Dong Ping; Diez, Paula Aguilera

    Systems, apparatuses, and methods for implementing efficient queues and other data structures. A queue may be shared among multiple processors and/or threads without using explicit software atomic instructions to coordinate access to the queue. System software may allocate an atomic queue and corresponding queue metadata in system memory and return, to the requesting thread, a handle referencing the queue metadata. Any number of threads may utilize the handle for accessing the atomic queue. The logic for ensuring the atomicity of accesses to the atomic queue may reside in a management unit in the memory controller coupled to the memory wheremore » the atomic queue is allocated.« less

  7. Circuit Board Analysis for Lead by Atomic Absorption Spectroscopy in a Course for Nonscience Majors

    ERIC Educational Resources Information Center

    Weidenhammer, Jeffrey D.

    2007-01-01

    A circuit board analysis of the atomic absorption spectroscopy, which is used to measure lead content in a course for nonscience majors, is being presented. The experiment can also be used to explain the potential environmental hazards of unsafe disposal of various used electronic equipments.

  8. Extreme Adiabatic Expansion in Micro-gravity: Modeling for the Cold Atomic Laboratory

    NASA Astrophysics Data System (ADS)

    Sackett, C. A.; Lam, T. C.; Stickney, J. C.; Burke, J. H.

    2017-12-01

    The upcoming Cold Atom Laboratory mission for the International Space Station will allow the investigation of ultracold gases in a microgravity environment. Cold atomic samples will be produced using evaporative cooling in a magnetic chip trap. We investigate here the possibility to release atoms from the trap via adiabatic expansion. We discuss both general considerations and a detailed model of the planned apparatus. We find that it should be possible to reduce the mean trap confinement frequency to about 0.2 Hz, which will correspond to a three-dimensional sample temperature of about 150 pK and a mean atom velocity of 0.1 mm/s.

  9. Extreme Adiabatic Expansion in Micro-gravity: Modeling for the Cold Atomic Laboratory

    NASA Astrophysics Data System (ADS)

    Sackett, C. A.; Lam, T. C.; Stickney, J. C.; Burke, J. H.

    2018-05-01

    The upcoming Cold Atom Laboratory mission for the International Space Station will allow the investigation of ultracold gases in a microgravity environment. Cold atomic samples will be produced using evaporative cooling in a magnetic chip trap. We investigate here the possibility to release atoms from the trap via adiabatic expansion. We discuss both general considerations and a detailed model of the planned apparatus. We find that it should be possible to reduce the mean trap confinement frequency to about 0.2 Hz, which will correspond to a three-dimensional sample temperature of about 150 pK and a mean atom velocity of 0.1 mm/s.

  10. Bismuth as a general internal standard for lead in atomic absorption spectrometry.

    PubMed

    Bechlin, Marcos A; Fortunato, Felipe M; Ferreira, Edilene C; Gomes Neto, José A; Nóbrega, Joaquim A; Donati, George L; Jones, Bradley T

    2014-06-11

    Bismuth was evaluated as internal standard for Pb determination by line source flame atomic absorption spectrometry (LS FAAS), high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) and line source graphite furnace atomic absorption spectrometry (LS GFAAS). Analysis of samples containing different matrices indicated close relationship between Pb and Bi absorbances. Correlation coefficients of calibration curves built up by plotting A(Pb)/A(Bi)versus Pb concentration were higher than 0.9953 (FAAS) and higher than 0.9993 (GFAAS). Recoveries of Pb improved from 52-118% (without IS) to 97-109% (IS, LS FAAS); 74-231% (without IS) to 96-109% (IS, HR-CS FAAS); and 36-125% (without IS) to 96-110% (IS, LS GFAAS). The relative standard deviations (n=12) were reduced from 0.6-9.2% (without IS) to 0.3-4.3% (IS, LS FAAS); 0.7-7.7% (without IS) to 0.1-4.0% (IS, HR-CS FAAS); and 2.1-13% (without IS) to 0.4-5.9% (IS, LS GFAAS). Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Transition metal atomic multiplets in the ligand K-edge x-ray absorption spectra and multiple oxidation states in the L2,3 emission of strongly correlated compounds

    NASA Astrophysics Data System (ADS)

    Jiménez-Mier, J.; Olalde-Velasco, P.; Yang, W.-L.; Denlinger, J.

    2014-07-01

    We present results that show that atomic multiplet ligand field calculations are in very good agreement with experimental x-ray absorption spectra at the L2,3 edge of transition metal (TM) di-fluorides (MF2, MCrCu). For chromium more than one TM oxidation state is needed to achieve such an agreement. We also show that signature of the TM atomic multiplet can be found at the pre-edge of the fluorine K-edge x-ray absorption spectra. TM atomic multiplet ligand field calculations with a structureless core hole show good agreement with the observed pre-edges in the experimental fluorine absorption spectra. Preliminary results for the comparison between calculated and experimental resonant x-ray emission spectra for nominal CrF2 with more than one oxidation state indicate the presence of three chromium oxidation states in the bulk.

  12. Apparatus for making environmentally stable reactive alloy powders

    DOEpatents

    Anderson, I.E.; Lograsso, B.K.; Terpstra, R.L.

    1996-12-31

    Apparatus and method are disclosed for making powder from a metallic melt by atomizing the melt to form droplets and reacting the droplets downstream of the atomizing location with a reactive gas. The droplets are reacted with the gas at a temperature where a solidified exterior surface is formed thereon and where a protective refractory barrier layer (reaction layer) is formed whose penetration into the droplets is limited by the presence of the solidified surface so as to avoid selective reduction of key reactive alloyants needed to achieve desired powder end use properties. The barrier layer protects the reactive powder particles from environmental constituents such as air and water in the liquid or vapor form during subsequent fabrication of the powder to end-use shapes and during use in the intended service environment. 7 figs.

  13. Synthesis of silicon containing materials using liquid hydrosilane compositions through direct injection

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Srinivasan, Guruvenket; Sailer, Robert A.; Hoey, Justin

    An apparatus and a non-vapor-pressure dependent method of chemical vapor deposition of Si based materials using direct injection of liquid hydrosilane(s) are presented. Liquid silane precursor solutions may also include metal, non-metal or metalloid dopants, nanomaterials and solvents. An illustrative apparatus has a precursor solution and carrier gas system, atomizer and deposit head with interior chamber and a hot plate supporting the substrate. Atomized liquid silane precursor solutions and carrier gas moves through a confined reaction zone that may be heated and the aerosol and vapor are deposited on a substrate to form a thin film. The substrate may bemore » heated prior to deposition. The deposited film may be processed further with thermal or laser processing.« less

  14. Filtrates and Residues: Measuring the Atomic or Molecular Mass of a Gas with a Tire Gauge and a Butane Lighter Fluid Can.

    ERIC Educational Resources Information Center

    Bodner, George M.; Magginnis, Lenard J.

    1985-01-01

    Describes the use of an inexpensive apparatus (based on a butane lighter fluid can and a standard tire pressure gauge) in measuring the atomic/molecular mass of an unknown gas and in demonstrating the mass of air or the dependence of pressure on the mass of a gas. (JN)

  15. Droplet size prediction in the production of drug delivery microsystems by ultrasonic atomization

    PubMed Central

    Dalmoro, Annalisa; d’Amore, Matteo; Barba, Anna Angela

    Microencapsulation processes of drugs or other functional molecules are of great interest in pharmaceutical production fields. Ultrasonic assisted atomization is a new technique to produce microencapsulated systems by mechanical approach. It seems to offer several advantages (low level of mechanical stress in materials, reduced energy request, reduced apparatuses size) with respect to more conventional techniques. In this paper the groundwork of atomization is briefly introduced and correlations to predict droplet size starting from process parameters and material properties are presented. PMID:24251250

  16. Remote laser evaporative molecular absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Hughes, Gary B.; Lubin, Philip; Cohen, Alexander; Madajian, Jonathan; Kulkarni, Neeraj; Zhang, Qicheng; Griswold, Janelle; Brashears, Travis

    2016-09-01

    We describe a novel method for probing bulk molecular and atomic composition of solid targets from a distant vantage. A laser is used to melt and vaporize a spot on the target. With sufficient flux, the spot temperature rises rapidly, and evaporation of surface materials occurs. The melted spot creates a high-temperature blackbody source, and ejected material creates a plume of surface materials in front of the spot. Molecular and atomic absorption occurs as the blackbody radiation passes through the ejected plume. Bulk molecular and atomic composition of the surface material is investigated by using a spectrometer to view the heated spot through the ejected plume. The proposed method is distinct from current stand-off approaches to composition analysis, such as Laser-Induced Breakdown Spectroscopy (LIBS), which atomizes and ionizes target material and observes emission spectra to determine bulk atomic composition. Initial simulations of absorption profiles with laser heating show great promise for Remote Laser-Evaporative Molecular Absorption (R-LEMA) spectroscopy. The method is well-suited for exploration of cold solar system targets—asteroids, comets, planets, moons—such as from a spacecraft orbiting the target. Spatial composition maps could be created by scanning the surface. Applying the beam to a single spot continuously produces a borehole or trench, and shallow subsurface composition profiling is possible. This paper describes system concepts for implementing the proposed method to probe the bulk molecular composition of an asteroid from an orbiting spacecraft, including laser array, photovoltaic power, heating and ablation, plume characteristics, absorption, spectrometry and data management.

  17. VUV absorption spectroscopy measurements of the role of fast neutral atoms in high-power gap breakdown

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    FILUK,A.B.; BAILEY,JAMES E.; CUNEO,MICHAEL E.

    The maximum power achieved in a wide variety of high-power devices, including electron and ion diodes, z pinches, and microwave generators, is presently limited by anode-cathode gap breakdown. A frequently-discussed hypothesis for this effect is ionization of fast neutral atoms injected throughout the anode-cathode gap during the power pulse. The authors describe a newly-developed diagnostic tool that provides the first direct test of this hypothesis. Time-resolved vacuum-ultraviolet absorption spectroscopy is used to directly probe fast neutral atoms with 1 mm spatial resolution in the 10 mm anode-cathode gap of the SABRE 5 MV, 1 TW applied-B ion diode. Absorption spectramore » collected during Ar RF glow discharges and with CO{sub 2} gas fills confirm the reliability of the diagnostic technique. Throughout the 50--100 ns ion diode pulses no measurable neutral absorption is seen, setting upper limits of 0.12--1.5 x 10{sup 14} cm{sup {minus}3} for ground state fast neutral atom densities of H, C, N, O, F. The absence of molecular absorption bands also sets upper limits of 0.16--1.2 x 10{sup 15} cm{sup {minus}3} for common simple molecules. These limits are low enough to rule out ionization throughout the gap as a breakdown mechanism. This technique can now be applied to quantify the role of neutral atoms in other high-power devices.« less

  18. Infrared absorption nano-spectroscopy using sample photoexpansion induced by tunable quantum cascade lasers.

    PubMed

    Lu, Feng; Belkin, Mikhail A

    2011-10-10

    We report a simple technique that allows obtaining mid-infrared absorption spectra with nanoscale spatial resolution under low-power illumination from tunable quantum cascade lasers. Light absorption is detected by measuring associated sample thermal expansion with an atomic force microscope. To detect minute thermal expansion we tune the repetition frequency of laser pulses in resonance with the mechanical frequency of the atomic force microscope cantilever. Spatial resolution of better than 50 nm is experimentally demonstrated.

  19. Low loss liquid crystal photonic bandgap fiber in the near-infrared region

    NASA Astrophysics Data System (ADS)

    Scolari, Lara; Wei, Lei; Gauza, Sebastian; Wu, Shin-Tson; Bjarklev, Anders

    2011-01-01

    We infiltrate a perdeuterated liquid crystal with a reduced infrared absorption in a photonic crystal fiber. The H atoms of this liquid crystal were substituted with D atoms in order to move the vibration bands which cause absorption loss to longer wavelengths and therefore reduce the absorption in the spectral range of 1-2 μm. We achieve in the middle of the near-infrared transmission bandgap the lowest loss (about 1 dB) ever reported for this kind of devices.

  20. Selective determination of arsenic(III) and arsenic(V) with ammonium pyrrolidinedithiocarbamate, sodium diethyldithiocarbamate and dithizone by means of flameless atomic-absorption spectrophotometry with a carbon-tube atomizer.

    PubMed

    Kamada, T

    The extraction behaviour of arsenic(III) and arsenic(V) with ammonium pyrrolidinedithiocarbamate, sodium diethyldithiocarbamate and dithizone in organic solvents has been investigated by means of nameless atomic-absorption spectrophotometry with a carbon-tube atomizer. The selective extraction of arsenic(III) and differential determination of arsenic(III) and arsenic(V) have been developed. With ammonium pyrrolidinedithiocarbamate and methyl isobutyl ketone or nitrobenzene, when the aqueous phase/solvent volume ratio is 5 and the injection volume in the carbon tube is 20 mul, the sensitivities for 1% absorption are 0.4 and 0.5 part per milliard of arsenic, respectively. The relative standard deviations are ca. 3%. Interference by many metal ions can be prevented by masking with EDTA. The proposed methods are applied satisfactorily for determination of As(III) and As(V) in various types of water.

  1. Cold atomic hydrogen in the inner galaxy

    NASA Technical Reports Server (NTRS)

    Dickey, J. M.; Garwood, R. W.

    1986-01-01

    The VLA is used to measure 21 cm absorption in directions with the absolute value of b less than 1 deg., the absolute value of 1 less than 25 deg. to probe the cool atomic gas in the inner galaxy. Abundant H I absorption is detected; typical lines are deep and narrow, sometimes blending in velocity with adjacent features. Unlike 21 cm emission not all allowed velocities are covered: large portions of the l-v diagram are optically thin. Although not similar to H I emission, the absorption shows a striking correspondence with CO emission in the inner galaxy: essentially every strong feature detected in one survey is seen in the other. The provisional conclusion is that in the inner galaxy most cool atomic gas is associated with molecular cloud complexes. There are few or no cold atomic clouds devoid of molecules in the inner galaxy, although these are common in the outer galaxy.

  2. X-ray absorption spectroscopic studies of the active sites of nickel- and copper-containing metalloproteins

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tan, Grace O.

    1993-06-01

    X-ray absorption spectroscopy (XAS) is a useful tool for obtaining structural and chemical information about the active sites of metalloproteins and metalloenzymes. Information may be obtained from both the edge region and the extended X-ray absorption fine structure (EXAFS) or post-edge region of the K-edge X-ray absorption spectrum of a metal center in a compound. The edge contains information about the valence electronic structure of the atom that absorbs the X-rays. It is possible in some systems to infer the redox state of the metal atom in question, as well as the geometry and nature of ligands connected to it,more » from the features in the edge in a straightforward manner. The EXAFS modulations, being produced by the backscattering of the ejected photoelectron from the atoms surrounding the metal atom, provide, when analyzed, information about the number and type of neighbouring atoms, and the distances at which they occur. In this thesis, analysis of both the edge and EXAFS regions has been used to gain information about the active sites of various metalloproteins. The metalloproteins studied were plastocyanin (Pc), laccase and nickel carbon monoxide dehydrogenase (Ni CODH). Studies of Cu(I)-imidazole compounds, related to the protein hemocyanin, are also reported here.« less

  3. Dense plasma focus production in a hypocycloidal pinch

    NASA Technical Reports Server (NTRS)

    Lee, J. H.; Mcfarland, D. R.; Hohl, F.

    1975-01-01

    A type of high-power pinch apparatus consisting of disk electrodes was developed, and diagnostic measurements to study its mechanism of dense plasma production were made. The collapse fronts of the current sheets are well organized, and dense plasma focuses are produced on the axis with radial stability in excess of 5 microns. A plasma density greater than 10 to the 18th power/cubic cm was determined with Stark broadening and CO2 laser absorption. A plasma temperature of approximately 1 keV was measured with differential transmission of soft X-rays through thin foils. Essentially complete absorption of a high-energy CO2 laser beam was observed. The advantages of this apparatus over the coaxial plasma focus are in (1) the plasma volume, (2) the stability, (3) the containment time, (4) the easy access to additional heating by laser or electron beams, and (5) the possibility of scaling up to a multiple array for high-power operation.

  4. Spacecraft thermal energy accommodation from atomic recombination

    NASA Technical Reports Server (NTRS)

    Carleton, Karen L.; Marinelli, William J.

    1991-01-01

    Measurements of atomic recombination probabilities important in determining energy release to reusable spacecraft thermal protection surfaces during reentry are presented. An experimental apparatus constructed to examine recombination of atomic oxygen from thermal protection and reference materials at reentry temperatures is described. The materials are examined under ultrahigh vacuum conditions to develop and maintain well characterized surface conditions that are free of contamination. When compared with stagnation point heat transfer measurements performed in arc jet facilities, these measurements indicate that a significant fraction of the excess energy available from atom recombination is removed from the surface as metastable O2.

  5. Cadmium, copper, lead, and zinc determination in precipitation: A comparison of inductively coupled plasma atomic emission spectrometry and graphite furnace atomization atomic absorption spectrometry

    USGS Publications Warehouse

    Reddy, M.M.; Benefiel, M.A.; Claassen, H.C.

    1987-01-01

    Selected trace element analysis for cadmium, copper, lead, and zinc in precipitation samples by inductively coupled plasma atomic emission Spectrometry (ICP) and by atomic absorption spectrometry with graphite furnace atomization (AAGF) have been evaluated. This task was conducted in conjunction with a longterm study of precipitation chemistry at high altitude sites located in remote areas of the southwestern United States. Coefficients of variation and recovery values were determined for a standard reference water sample for all metals examined for both techniques. At concentration levels less than 10 micrograms per liter AAGF analyses exhibited better precision and accuracy than ICP. Both methods appear to offer the potential for cost-effective analysis of trace metal ions in precipitation. ?? 1987 Springer-Verlag.

  6. [Determination of sulfur in plant using a high-resolution continuum source atomic absorption spectrometer].

    PubMed

    Wang, Yu; Li, Jia-xi

    2009-05-01

    A method for the analysis of sulfur (S) in plant by molecular absorption of carbon monosulfide (CS) using a high-resolution continuum source atomic absorption spectrometer (CS AAS) with a fuel-rich air/acetylene flame has been devised. The strong CS absorption band was found around 258 nm. The half-widths of some absorption bands were of the order of picometers, the same as the common atomic absorption lines. The experimental procedure in this study provided optimized instrumental conditions (the ratio of acetylene to air, the burner height) and parameters, and researched the spectral interferences and chemical interferences. The influence of the organic solvents on the CS absorption signals and the different digestion procedures for the determination of sulfur were also investigated. The limit of detection achieved for sulfur was 14 mg x L(-1), using the CS wavelength of 257. 961 nm and a measurement time of 3 s. The accuracy and precision were verified by analysis of two plant standard reference materials. The major applications of this method have been used for the determination of sulfur in plant materials, such as leaves. Compared to the others, this method for the analysis of sulfur is rapid, easy and simple for sulfur determination in plant.

  7. Simple technique of talc delivery for video-assisted talc pleurodesis.

    PubMed

    Jutley, Rajwinder S; Waqar, Salman; Raha, Neil; Fenton, Paul; Sarkar, Pradip K

    2009-02-01

    It has been proven that talc is the sclerosant of choice for pleurodesis, especially for malignant effusions. Uniform talc deposition on the visceral pleura is often difficult, resulting in clump deposition with the use of an atomizer or bladder syringe delivery apparatus. We have devised a simple sterile apparatus that allows the operator to retain full control over the talc delivery rate and coat the lung uniformly under direct vision using a pressurized system.

  8. Resonant-cavity antenna for plasma heating

    DOEpatents

    Perkins, F.W. Jr.; Chiu, S.C.; Parks, P.; Rawls, J.M.

    1984-01-10

    This invention relates generally to a method and apparatus for transferring energy to a plasma immersed in a magnetic field, and relates particularly to an apparatus for heating a plasma of low atomic number ions to high temperatures by transfer of energy to plasma resonances, particularly the fundamental and harmonics of the ion cyclotron frequency of the plasma ions. This invention transfers energy from an oscillating radio-frequency field to a plasma resonance of a plasma immersed in a magnetic field.

  9. Microwave absorption properties of carbon nanocoils coated with highly controlled magnetic materials by atomic layer deposition.

    PubMed

    Wang, Guizhen; Gao, Zhe; Tang, Shiwei; Chen, Chaoqiu; Duan, Feifei; Zhao, Shichao; Lin, Shiwei; Feng, Yuhong; Zhou, Lei; Qin, Yong

    2012-12-21

    In this work, atomic layer deposition is applied to coat carbon nanocoils with magnetic Fe(3)O(4) or Ni. The coatings have a uniform and highly controlled thickness. The coated nanocoils with coaxial multilayer nanostructures exhibit remarkably improved microwave absorption properties compared to the pristine carbon nanocoils. The enhanced absorption ability arises from the efficient complementarity between complex permittivity and permeability, chiral morphology, and multilayer structure of the products. This method can be extended to exploit other composite materials benefiting from its convenient control of the impedance matching and combination of dielectric-magnetic multiple loss mechanisms for microwave absorption applications.

  10. Fundamental Studies on Donor-acceptor Conjugated Polymers Containing 'Heavy' Group 14 and Group 16 Elements

    NASA Astrophysics Data System (ADS)

    Gibson, Gregory Laird

    One advantage of conjugated polymers as organic materials is that their properties may be readily tuned through covalent modifications. This thesis presents studies on the structure-property relationships resulting from single- and double-atom substitutions on an alternating donor-acceptor conjugated polymer. Specifically, single selenium and tellurium atoms have been incorporated into the acceptor monomer in place of sulfur; silicon and germanium atoms have been substituted in place of carbon at the donor monomer bridge position. The carbon-donor/ tellurium-acceptor polymer was synthesized by a post-polymerization reaction sequence and demonstrated the utility of heavy group 16 atoms to red shift a polymer absorption spectrum. Density functional theory calculations point to a new explanation for this result invoking the lower heavy atom ionization energy and reduced aromaticity of acceptor monomers containing selenium and tellurium compared to sulfur. Absorption and emission experiments demonstrate that both silicon and germanium substitutions in the donor slightly blue shift the polymer absorption spectrum. Polymers containing sulfur in the acceptor are the strongest light absorbers of all polymers studied here. Molecular weight and phenyl end capping studies show that molecular weight appears to affect polymer absorption to the greatest degree in a medium molecular weight regime and that these effects have a significant aggregation component. Solar cell devices containing either the silicon- or germanium-donor/selenium-acceptor polymer display improved red light harvesting or hole mobility relative to their structural analogues. Overall, these results clarify the effects of single atom substitution on donor-acceptor polymers and aid in the future design of polymers containing heavy atoms.

  11. Extra-corporeal blood access, sensing, and radiation methods and apparatuses

    NASA Technical Reports Server (NTRS)

    Castle, Kent D. (Inventor)

    1993-01-01

    The described invention is related to extra-corporeal blood access and radiation methods and apparatuses and, in particular, to subjecting flowing blood to energy in variety of forms, including radiation, electromagnetic force fields or atomic particles. It is directed to methods and apparatuses for accessing flowing blood and for subjecting the blood to electrical conductive, electrostatic or electromagnetic fields or for radiating the blood with some type of radiation, e.g., radio waves, ultrasonic or audio waves, microwaves, IR rays, visible light, UV radiation, x-rays, alpha, beta or gamma rays. An apparatus is employed which includes one or more access ports or windows for radiating blood and/or for sensing/analyzing blood. This invention is useful for killing viruses and bacteria in blood, monitoring blood for medical purposes, genetic modification of blood, and analyzing and/or treating blood components.

  12. Overcoming Matrix Effects in a Complex Sample: Analysis of Multiple Elements in Multivitamins by Atomic Absorption Spectroscopy

    ERIC Educational Resources Information Center

    Arnold, Randy J.; Arndt, Brett; Blaser, Emilia; Blosser, Chris; Caulton, Dana; Chung, Won Sog; Fiorenza, Garrett; Heath, Wyatt; Jacobs, Alex; Kahng, Eunice; Koh, Eun; Le, Thao; Mandla, Kyle; McCory, Chelsey; Newman, Laura; Pithadia, Amit; Reckelhoff, Anna; Rheinhardt, Joseph; Skljarevski, Sonja; Stuart, Jordyn; Taylor, Cassie; Thomas, Scott; Tse, Kyle; Wall, Rachel; Warkentien, Chad

    2011-01-01

    A multivitamin tablet and liquid are analyzed for the elements calcium, magnesium, iron, zinc, copper, and manganese using atomic absorption spectrometry. Linear calibration and standard addition are used for all elements except calcium, allowing for an estimate of the matrix effects encountered for this complex sample. Sample preparation using…

  13. A Simplified Digestion Protocol for the Analysis of Hg in Fish by Cold Vapor Atomic Absorption Spectroscopy

    ERIC Educational Resources Information Center

    Kristian, Kathleen E.; Friedbauer, Scott; Kabashi, Donika; Ferencz, Kristen M.; Barajas, Jennifer C.; O'Brien, Kelly

    2015-01-01

    Analysis of mercury in fish is an interesting problem with the potential to motivate students in chemistry laboratory courses. The recommended method for mercury analysis in fish is cold vapor atomic absorption spectroscopy (CVAAS), which requires homogeneous analyte solutions, typically prepared by acid digestion. Previously published digestion…

  14. Improved hopcalite procedure for the determination of mercury vapor in air by flameless atomic absorption.

    PubMed

    Rathje, A O; Marcero, D H

    1976-05-01

    Mercury vapor is efficiently trapped from air by passage through a small glass tube filled with hopcalite. The hopcalite and adsorbed mercury are dissolved in a mixture of nitric and hydrochloric acids. Solution is rapid and complete, with no loss of mercury. Analysis is completed by flameless atomic absorption.

  15. Interstellar photoelectric absorption cross sections, 0.03-10 keV

    NASA Technical Reports Server (NTRS)

    Morrison, R.; Mccammon, D.

    1983-01-01

    An effective absorption cross section per hydrogen atom has been calculated as a function of energy in the 0.03-10 keV range using the most recent atomic cross section and cosmic abundance data. Coefficients of a piecewise polynomial fit to the numerical results are given to allow convenient application in automated calculations.

  16. Direct Electrothermal Atomic Absorption Determination of Trace Elements in Body Fluids (Review)

    NASA Astrophysics Data System (ADS)

    Zacharia, A. N.; Arabadji, M. V.; Chebotarev, A. N.

    2017-03-01

    This review is focused on the state and development of tendencies of electrothermal atomic absorption spectroscopy over the last 25 years (from 1990 to 2016) in the direct determination of Cu, Zn, Pb, Cd, Mn, Se, As, Cr, Co, Ni, Al, and Hg in body fluids such as blood, urine, saliva, and breast milk.

  17. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of antimony by automated-hydride atomic absorption spectrophotometry

    USGS Publications Warehouse

    Brown, G.E.; McLain, B.J.

    1994-01-01

    The analysis of natural-water samples for antimony by automated-hydride atomic absorption spectrophotometry is described. Samples are prepared for analysis by addition of potassium and hydrochloric acid followed by an autoclave digestion. After the digestion, potassium iodide and sodium borohydride are added automatically. Antimony hydride (stibine) gas is generated, then swept into a heated quartz cell for determination of antimony by atomic absorption spectrophotometry. Precision and accuracy data are presented. Results obtained on standard reference water samples agree with means established by interlaboratory studies. Spike recoveries for actual samples range from 90 to 114 percent. Replicate analyses of water samples of varying matrices give relative standard deviations from 3 to 10 percent.

  18. Apparatus and method for measurement of weak optical absorptions by thermally induced laser pulsing

    DOEpatents

    Cremers, D.A.; Keller, R.A.

    1982-06-08

    The thermal lensing phenomenon is used as the basis for measurement of weak optical absorptions when a cell containing the sample to be investigated is inserted into a normally continuous-wave operation laser-pumped dye laser cavity for which the output coupler is deliberately tilted relative to intracavity circulating laser light, and pulsed laser output ensues, the pulsewidth of which can be rlated to the sample absorptivity by a simple algorithm or calibration curve. A minimum detection limit of less than 10/sup -5/ cm/sup -1/ has been demonstrated using this technique.

  19. Apparatus and method for measurement of weak optical absorptions by thermally induced laser pulsing

    DOEpatents

    Cremers, D.A.; Keller, R.A.

    1985-10-01

    The thermal lensing phenomenon is used as the basis for measurement of weak optical absorptions when a cell containing the sample to be investigated is inserted into a normally continuous-wave operation laser-pumped dye laser cavity for which the output coupler is deliberately tilted relative to intracavity circulating laser light, and pulsed laser output ensues, the pulsewidth of which can be related to the sample absorptivity by a simple algorithm or calibration curve. A minimum detection limit of less than 10[sup [minus]5] cm[sup [minus]1] has been demonstrated using this technique. 6 figs.

  20. Apparatus and method for measurement of weak optical absorptions by thermally induced laser pulsing

    DOEpatents

    Cremers, David A.; Keller, Richard A.

    1985-01-01

    The thermal lensing phenomenon is used as the basis for measurement of weak optical absorptions when a cell containing the sample to be investigated is inserted into a normally continuous-wave operation laser-pumped dye laser cavity for which the output coupler is deliberately tilted relative to intracavity circulating laser light, and pulsed laser output ensues, the pulsewidth of which can be related to the sample absorptivity by a simple algorithm or calibration curve. A minimum detection limit of less than 10.sup.-5 cm.sup.-1 has been demonstrated using this technique.

  1. An Unusual Strong Visible-Light Absorption Band in Red Anatase TiO2 Photocatalyst Induced by Atomic Hydrogen-Occupied Oxygen Vacancies.

    PubMed

    Yang, Yongqiang; Yin, Li-Chang; Gong, Yue; Niu, Ping; Wang, Jian-Qiang; Gu, Lin; Chen, Xingqiu; Liu, Gang; Wang, Lianzhou; Cheng, Hui-Ming

    2018-02-01

    Increasing visible light absorption of classic wide-bandgap photocatalysts like TiO 2 has long been pursued in order to promote solar energy conversion. Modulating the composition and/or stoichiometry of these photocatalysts is essential to narrow their bandgap for a strong visible-light absorption band. However, the bands obtained so far normally suffer from a low absorbance and/or narrow range. Herein, in contrast to the common tail-like absorption band in hydrogen-free oxygen-deficient TiO 2 , an unusual strong absorption band spanning the full spectrum of visible light is achieved in anatase TiO 2 by intentionally introducing atomic hydrogen-mediated oxygen vacancies. Combining experimental characterizations with theoretical calculations reveals the excitation of a new subvalence band associated with atomic hydrogen filled oxygen vacancies as the origin of such band, which subsequently leads to active photo-electrochemical water oxidation under visible light. These findings could provide a powerful way of tailoring wide-bandgap semiconductors to fully capture solar light. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Simple method for determination of selenium in biological materials by flameless atomic-absorption spectrometry using a carbon-tube atomizer.

    PubMed

    Ishizaki, M

    1978-03-01

    A method for determination of selenium in biological materials by flameless atomic-absorption spectrometry using a carbon-tube atomizer is described. The sample is burned by an oxygen-flask combustion procedure, the resulting solution is treated with a cation-exchange resin to eliminate interfering cations, the selenium is extracted with dithizone in carbon tetrachloride and the resulting selenium dithizonate is combined with nickel nitrate in the carbon tube to enhance the sensitivity for selenium and avoid volatilization losses. The method measures selenium concentrations as low as 0.01 mug/g with a relative standard deviation of 8%.

  3. Mesoporous Silica Nanoparticles as an Adsorbent for Preconcentration and Determination of Trace Amount of Nickel in Environmental Samples by Atom Trap Flame Atomic Absorption Spectrometry

    NASA Astrophysics Data System (ADS)

    Shirkhanloo, H.; Falahnejad, M.; Zavvar Mousavi, H.

    2016-01-01

    A rapid enrichment method based on solid-phase extraction (SPE) has been established for preconcentration and separation of trace Ni(II) ions in water samples prior to their determination by atom trap flame atomic absorption spectrometry. A column filled with bulky NH2-UVM7 was used as the novel adsorbent. Under optimal conditions, the linear range, limit of detection (LOD), and preconcentration factor (PF) were 3-92 μg/L, 0.8 μg/L, and 100, respectively. The validity of the method was checked by the standard reference material.

  4. Theoretical study of Ag doping-induced vacancies defects in armchair graphene

    NASA Astrophysics Data System (ADS)

    Benchallal, L.; Haffad, S.; Lamiri, L.; Boubenider, F.; Zitoune, H.; Kahouadji, B.; Samah, M.

    2018-06-01

    We have performed a density functional theory (DFT) study of the absorption of silver atoms (Ag,Ag2 and Ag3) in graphene using SIESTA code, in the generalized gradient approximation (GGA). The absorption energy, geometry, magnetic moments and charge transfer of Ag clusters-graphene system are calculated. The minimum energy configuration demonstrates that all structures remain planar and silver atoms fit into this plane. The charge transfer between the silver clusters and carbon atoms constituting the graphene surface is an indicative of a strong bond. The structure doped with a single silver atom has a magnetic moment and the two other are nonmagnetic.

  5. Laboratory Measurements of Charge Transfer on Atomic Hydrogen at Thermal Energies

    NASA Technical Reports Server (NTRS)

    Havener, C. C.; Vane, C. R.; Krause, H. F.; Stancil, P. C.; Mroczkowski, T.; Savin, D. W.

    2002-01-01

    We describe our ongoing program to measure velocity dependent charge transfer (CT) cross sections for selected ions on atomic hydrogen using the ion-aloin merged-beams apparatus at Oak Ridge Natioiial Laboralory. Our focus is on those ions for which CT plays an important role in determining the ionization structure, line emis sion, and thermal structure of observed cosmic photoionized plasmas.

  6. In situ calibration of inductively coupled plasma-atomic emission and mass spectroscopy

    DOEpatents

    Braymen, Steven D.

    1996-06-11

    A method and apparatus for in situ addition calibration of an inductively coupled plasma atomic emission spectrometer or mass spectrometer using a precision gas metering valve to introduce a volatile calibration gas of an element of interest directly into an aerosol particle stream. The present situ calibration technique is suitable for various remote, on-site sampling systems such as laser ablation or nebulization.

  7. Learning about Modes in Atomic Force Microscopy by Means of Hands-On Activities Based on a Simple Apparatus

    ERIC Educational Resources Information Center

    Phuapaiboon, Unchada; Panijpan, Bhinyo; Osotchan, Tanakorn

    2009-01-01

    This study was conducted to examine the results of using a low-cost hands-on setup in combination with accompanying activities to promote understanding of the contact mode of atomic force microscopy (AFM). This contact mode setup enabled learners to study how AFM works by hand scanning using probing cantilevers with different characteristics on…

  8. In situ/non-contact superfluid density measurement apparatus

    NASA Astrophysics Data System (ADS)

    Nam, Hyoungdo; Su, Ping-Hsang; Shih, Chih-Kang

    2018-04-01

    We present a double-coil apparatus designed to operate with in situ capability, which is strongly desired for superconductivity studies on recently discovered two-dimensional superconductors. Coupled with a scanning tunneling microscope, the study of both local and global superconductivity [for superconducting gap and superfluid density (SFD), respectively] is possible on an identical sample without sample degradations due to damage, contamination, or oxidation in an atmosphere. The performance of the double-coil apparatus was tested on atomically clean surfaces of non-superconducting Si(111)-7 × 7 and on superconducting films of 100 nm-thick Pb and 1.4 nm-ultrathin Pb. The results clearly show the normal-to-superconductor phase transition for Pb films with a strong SFD.

  9. Observing random walks of atoms in buffer gas through resonant light absorption

    NASA Astrophysics Data System (ADS)

    Aoki, Kenichiro; Mitsui, Takahisa

    2016-07-01

    Using resonant light absorption, random-walk motions of rubidium atoms in nitrogen buffer gas are observed directly. The transmitted light intensity through atomic vapor is measured, and its spectrum is obtained, down to orders of magnitude below the shot-noise level to detect fluctuations caused by atomic motions. To understand the measured spectra, the spectrum for atoms performing random walks in a Gaussian light beam is computed, and its analytical form is obtained. The spectrum has 1 /f2 (f is frequency) behavior at higher frequencies, crossing over to a different, but well-defined, behavior at lower frequencies. The properties of this theoretical spectrum agree excellently with the measured spectrum. This understanding also enables us to obtain the diffusion constant, the photon cross section of atoms in buffer gas, and the atomic number density from a single spectral measurement. We further discuss other possible applications of our experimental method and analysis.

  10. Dynamical Evolution of Properties for Atom and Field in the Process of Two-Photon Absorption and Emission Between Atomic Levels

    NASA Astrophysics Data System (ADS)

    Wang, Jian-ming; Xu, Xue-xiang

    2018-04-01

    Using dressed state method, we cleverly solve the dynamics of atom-field interaction in the process of two-photon absorption and emission between atomic levels. Here we suppose that the atom is initially in the ground state and the optical field is initially in Fock state, coherent state or thermal state, respectively. The properties of the atom, including the population in excited state and ground state, the atom inversion, and the properties for optical field, including the photon number distribution, the mean photon number, the second-order correlation function and the Wigner function, are discussed in detail. We derive their analytical expressions and then make numerical analysis for them. In contrast with Jaynes-Cummings model, some similar results, such as quantum Rabi oscillation, revival and collapse, are also exhibit in our considered model. Besides, some novel nonclassical states are generated.

  11. A measurement of the angular distribution of 5 eV atomic oxygen scattered off a solid surface in earth orbit

    NASA Technical Reports Server (NTRS)

    Gregory, John C.; Peters, Palmer N.

    1986-01-01

    The angular distribution of 5 eV atomic oxygen scattered off a polished vitreous carbon surface was measured on a recent Space Shuttle flight. The experimental apparatus was of novel design, completely passive, and used thin silver films as the recording device for oxygen atoms. Most of the incident oxygen was contained in the reflected beam and remained in an active form and probably still atoms. Allowance was made for 12 percent loss of incident atoms which are converted to CO at the carbon surface. The scattered distribution which is wide lobular, peaking 15 deg in the forward direction, shows almost but not quite full accommodation.

  12. Apparatus Notes.

    ERIC Educational Resources Information Center

    Eaton, Bruce G., Ed.

    1980-01-01

    Presents four notes that report new equipment and techniques of interest to physics teachers. These notes deal with collosions of atoms in solids, determining the viscosity of a liquid, measuring the speed of sound and demonstrating Doppler effect. (HM)

  13. Excitation of atoms and ions in plasmas by ultra-short electromagnetic pulses

    NASA Astrophysics Data System (ADS)

    Astapenko, V. A.; Sakhno, S. V.; Svita, S. Yu; Lisitsa, V. S.

    2017-02-01

    The problem of atoms and ions diagnostics in rarefied and dense plasmas by ultrashort laser pulses (USP) is under consideration. The application of USP provides: 1) excitation from ground states due to their carrier frequency high enough, 2) penetration into optically dense media due to short pulses duration. The excitation from ground atomic states increases sharply populations of excited atomic states in contrast with standard laser induced fluorescence spectroscopy based on radiative transitions between excited atomic states. New broadening parameter in radiation absorption, namely inverse pulse duration time 1/τ appears in addition to standard line-shape width in the profile G(ω). The Lyman-beta absorption spectra for USP are calculated for Holtsmark static broadening mechanism. Excitation of highly charged H-like ions in hot plasmas is described by both Gaussian shapes for Doppler broadening and pulse spectrum resulting in analytical absorption line-shape. USP penetration into optically thick media and corresponding excitation probability are calculated. It is shown a great effect of USP duration on excitation probabilities in optically thick media. The typical situations for plasma diagnostics by USP are discussed in details.

  14. Dating and Tracing Groundwater and Ice with 81Kr and 85Kr

    NASA Astrophysics Data System (ADS)

    Yang, Guomin; Tong, Amin; Dong, Xize; Gu, Jiqiang; Hu, Shuiming; Jiang, Wei; Lu, Zhengtian; Ritterbusch, Florian

    2017-04-01

    81Kr (half-life 229kyr) is an ideal tracer for old groundwater and ice in the age range of 105 - 106 years. To meet the increasing demands from the earth science community, a new and improved Atom Trap Trace Analysis (ATTA) apparatus is developed at the University of Science and Technology of China (USTC). This instrument is capable of analyzing over 300 samples per year. Each measurement requirs 1-2 uL STP of krypton gas, which can be extracted from 20-40 kg of water. New sampling and purification systems have also been developed at USTC. With the new portable sampling system, the time for on-site sampling is typically less than one hour. The same sampling and atom-trap apparatuses are also used to analyze 85Kr (half-life 11 yr) to trace young groundwater.

  15. Strong-field two-photon transition by phase shaping

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lee, Sangkyung; Lim, Jongseok; Ahn, Jaewook

    2010-08-15

    We demonstrate the ultrafast coherent control of a nonlinear two-photon absorption in a dynamically shifted energy level structure. We use a spectrotemporal laser-pulse shaping that is programed to preserve the resonant absorption condition during the intense laser-field interaction. Experiments carried out in the strong-field regime of two-photon absorption in the ground state of atomic cesium reveal that the analytically obtained offset and curvature of a laser spectrum compensate the effect of both static and dynamic energy shifts of the given light-atom interaction.

  16. Exploding conducting film laser pumping apparatus

    DOEpatents

    Ware, Kenneth D.; Jones, Claude R.

    1986-01-01

    Exploding conducting film laser optical pumping apparatus. The 342-nm molecular iodine and the 1.315-.mu.m atomic iodine lasers have been optically pumped by intense light from exploding-metal-film discharges. Brightness temperatures for the exploding-film discharges were approximately 25,000 K. Although lower output energies were achieved for such discharges when compared to exploding-wire techniques, the larger surface area and smaller inductance inherent in the exploding-film should lead to improved efficiency for optically-pumped gas lasers.

  17. Developing a Transdisciplinary Teaching Implement for Atomic Absorption Spectroscopy

    ERIC Educational Resources Information Center

    Drew, John

    2008-01-01

    In this article I explain why I wrote the set of teaching notes on Atomic Absorption Spectroscopy (AAS) and why they look the way they do. The notes were intended as a student reference to question, highlight and write over as much as they wish during an initial practical demonstration of the threshold concept being introduced, in this case…

  18. Assessing the Engagement, Learning, and Overall Experience of Students Operating an Atomic Absorption Spectrophotometer with Remote Access Technology

    ERIC Educational Resources Information Center

    Erasmus, Daniel J.; Brewer, Sharon E.; Cinel, Bruno

    2015-01-01

    The use of internet-based technologies in the teaching of laboratories has emerged as a promising education tool. This study evaluated the effectiveness of using remote access technology to operate an atomic absorption spectrophotometer in analyzing the iron content in a crude myoglobin extract. Sixty-two students were surveyed on their level of…

  19. The Use of a Microprocessor-Controlled, Video Output Atomic Absorption Spectrometer as an Educational Tool in a Two-Year Technical Curriculum.

    ERIC Educational Resources Information Center

    Kerfoot, Henry B.

    Based on instructional experiences at Charles County Community College, Maryland, this report examines the pedagogical advantage of teaching atomic absorption (AA) spectroscopy with an AA spectrophotometer that is equipped with a microprocessor and video output mechanism. The report first discusses the growing importance of AA spectroscopy in…

  20. The DTIC Review: Volume 2, Number 4, Surviving Chemical and Biological Warfare

    DTIC Science & Technology

    1996-12-01

    CHROMATOGRAPHIC ANALYSIS, NUCLEAR MAGNETIC RESONANCE, INFRARED SPECTROSCOPY , ARMY RESEARCH, DEGRADATION, VERIFICATION, MASS SPECTROSCOPY , LIQUID... mycotoxins . Such materials are not attractive as weapons of mass destruction however, as large amounts are required to produce lethal effects. In...VERIFICATION, ATOMIC ABSORPTION SPECTROSCOPY , ATOMIC ABSORPTION. AL The DTIC Review Defense Technical Information Center AD-A285 242 AD-A283 754 EDGEWOOO

  1. NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION AND MAINTENANCE OF THE PERKIN-ELMER 1100B ATOMIC ABSORPTION SPECTROMETER (BCO-L-5.1)

    EPA Science Inventory

    The purpose of this SOP is to outline the start-up, calibration, operation, and maintenance procedures for the Perkin-Elmer 5100 PC Atomic Absorption Spectrophotometer (PE 5100). These procedures are used for the determination of the target trace metal, as in soil, house dust, f...

  2. Facilities Management Guide for Asbestos and Lead

    DTIC Science & Technology

    2004-11-01

    equipment such as HEPA filtered power tools, portable welding exhaust systems, and paint removal equipment when work disturbs lead. Do not dry sweep ...sampling and analysis of [______] paint bulk and wipe samples by atomic absorption spectrophotometry (AA) or anodic stripping voltametry (ASV...analysis. e. All bulk (destructive) collected for lead shall be analyzed by atomic absorption spectrophotometry (AA) or anodic stripping voltametry

  3. Method and apparatus for selectively annealing heterostructures using microwave

    NASA Technical Reports Server (NTRS)

    Atwater, Harry A. (Inventor); Brain, Ruth A. (Inventor); Barmatz, Martin B. (Inventor)

    1998-01-01

    The present invention discloses a process for selectively annealing heterostructures using microwaves. A heterostructure, comprised of a material having higher microwave absorption and a material having lower microwave absorption, is exposed to microwaves in the cavity. The higher microwave absorbing material absorbs the microwaves and selectively heats while the lower microwave absorbing material absorbs small amounts of microwaves and minimally heats. The higher microwave absorbing material is thereby annealed onto the less absorbing material which is thermally isolated.

  4. Method and apparatus for selectively annealing heterostructures using microwaves

    NASA Technical Reports Server (NTRS)

    Atwater, Harry A. (Inventor); Brain, Ruth A. (Inventor); Barmatz, Martin B. (Inventor)

    1998-01-01

    The present invention discloses a process for selectively annealing heterostructures using microwaves. A heterostructure, comprised of a material having higher microwave absorption and a material having lower microwave absorption, is exposed to microwaves in the cavity. The higher microwave absorbing material absorbs the microwaves and selectively heats while the lower microwave absorbing material absorbs small amounts of microwaves and minimally heats. The higher microwave absorbing material is thereby annealed onto the less absorbing material which is thermally isolated.

  5. Micro-sampling method based on high-resolution continuum source graphite furnace atomic absorption spectrometry for calcium determination in blood and mitochondrial suspensions.

    PubMed

    Gómez-Nieto, Beatriz; Gismera, Mª Jesús; Sevilla, Mª Teresa; Satrústegui, Jorgina; Procopio, Jesús R

    2017-08-01

    A micro-sampling and straightforward method based on high resolution continuum source atomic absorption spectrometry (HR-CS AAS) was developed to determine extracellular and intracellular Ca in samples of interest in clinical and biomedical analysis. Solid sampling platforms were used to introduce the micro-samples into the graphite furnace atomizer. The secondary absorption line for Ca, located at 239.856nm, was selected to carry out the measurements. Experimental parameters such as pyrolysis and atomization temperatures and the amount of sample introduced for the measurements were optimized. Calibration was performed using aqueous standards and the approach to measure at the wings of the absorption lines was employed for the expansion of the linear response range. The limit of detection was of 0.02mgL -1 Ca (0.39ng Ca) and the upper limit of linear range was increased up to 8.0mgL -1 Ca (160ng Ca). The proposed method was used to determine Ca in mitochondrial suspensions and whole blood samples with successful results. Adequate recoveries (within 91-107%) were obtained in the tests performed for validation purposes. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Kinetic studies of halon replacements.

    NASA Astrophysics Data System (ADS)

    Orkin, Vladimir L.

    2013-04-01

    Despite their excellence as fire suppressants, the production of halons (bromofluorocarbons) is being phased out because of the danger they pose to the Earth's stratospheric ozone layer. A number of bromine free substances have been proposed and tested, but the effort to find replacements continues to return to bromine-containing compounds because of the properties of bromine as a chemically active flame suppressant. The primary approach to this problem has been to test candidate replacement compounds that have short atmospheric lifetimes or/and lack bromine, the halogen atoms that catalyze ozone destruction. Various chemical classes (alkanes, ethers, alkenes) have been studied both earlier and recently. The reaction with atmospheric hydroxyl radicals dictates the residence time and accumulation in the atmosphere of all potential halon replacements. Therefore, we improved a flash photolysis - resonance fluorescence apparatus to provide the most accurate OH reaction rate constants measured over the atmospheric temperatures. Supplementary UV absorption spectra were measured to allow the estimation of ODPs. Although a thorough 3-D modeling is required to assess ODPs, the simplified estimations can be made based on the compounds lifetimes.

  7. Investigation of heavy metal content of Turkish tobacco leaves, cigarette butt, ash, and smoke.

    PubMed

    Pelit, Füsun Okçu; Demirdöğen, Ruken Esra; Henden, Emür

    2013-11-01

    A procedure for the determination of cadmium, copper, manganese, and zinc in Turkish tobaccos, which were of different origins, years, and grades, and in the butt, ash, and smoke, which were obtained by smoking the cigarettes that were prepared manually from the said tobaccos in a smoking apparatus, was devised as proposed. The collected samples were digested by wet ashing technique by using HNO3-HClO4 and were analyzed by flame atomic absorption spectrometry with satisfactory recoveries (94% to 98%). The regression coefficients were above 0.99, and the detection limits were in the range of 0.03-0.12 mg/L(-1). The performance and accuracy of the method was tested by analyzing "Certified Reference Material GBW 08501-Peach Leaves." The determined values were in agreement with the standard values for the heavy metals analyzed. Thus, it was concluded that the developed method could offer a wide range of application for establishing a relationship between the makeup and composition of tobacco plant, products, ash, smoke, and smoking.

  8. Characterization of Toxic Metals in Tobacco, Tobacco Smoke, and Cigarette Ash from Selected Imported and Local Brands in Pakistan

    PubMed Central

    Ajab, Huma; Malik, Salman Akbar; Junaid, Muhammad; Yasmeen, Sadia; Abdullah, Mohd Azmuddin

    2014-01-01

    In this study, concentrations of Cd, Ni, Pb, and Cr were determined in tobacco, tobacco smoke-condensate, and cigarette ash for selected brands used in Pakistan. Smoking apparatus was designed for metal extraction from cigarette smoke. Samples were digested through microwave digester and then analyzed by flame atomic absorption spectrophotometer (FAAS). Higher concentration of Ni was detected in imported brands than the counterparts in the local brands. Pb levels were however higher in local brands while significant concentration of Cd was observed in both brands. For Cr, the level in tobacco of local brands was higher than their emitted smoke, whereas imported brands showed higher level in smoke than in tobacco. The cigarette ash retained 65 to 75% of the metal and about 25 to 30% went into the body. While this study revealed the serious requirement to standardize the manufacturing of tobacco products, more importantly is the urgent need for stronger enforcements to put in place to alert the general population about the hazardous effects of cigarettes and the health risks associated with these toxic metals. PMID:24672317

  9. Ion-beam treatment to prepare surfaces of p-CdTe films

    DOEpatents

    Gessert, Timothy A.

    2001-01-01

    A method of making a low-resistance electrical contact between a p-CdTe layer and outer contact layers by ion beam processing comprising: a) placing a CdS/CdTe device into a chamber and evacuating the chamber; b) orienting the p-CdTe side of the CdS/CdTe layer so that it faces apparatus capable of generating Ar atoms and ions of preferred energy and directionality; c) introducing Ar and igniting the area of apparatus capable of generating Ar atoms and ions of preferred energy and directionality in a manner so that during ion exposure, the source-to-substrate distance is maintained such that it is less than the mean-free path or diffusion length of the Ar atoms and ions at the vacuum pressure; d) allowing exposure of the p-CdTe side of the device to said ion beam for a period less than about 5 minutes; and e) imparting movement to the substrate to control the real uniformity of the ion-beam exposure on the p-CdTe side of the device.

  10. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: Probing atomic structure in situ

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Hsiu-Wen; Fanelli, Victor R.; Reiche, Helmut M.

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO{sub 2}more » measurements. The new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO{sub 2} sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H{sub 2} and natural gas uptake/storage.« less

  11. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: Probing atomic structure in situ

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Hsiu -Wen; Fanelli, Victor R.; Reiche, Helmut M.

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO 2measurements.more » As a result, the new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO 2 sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H 2 and natural gas uptake/storage.« less

  12. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: Probing atomic structure in situ

    DOE PAGES

    Wang, Hsiu -Wen; Fanelli, Victor R.; Reiche, Helmut M.; ...

    2014-12-24

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO 2measurements.more » As a result, the new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO 2 sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H 2 and natural gas uptake/storage.« less

  13. Determination of gold, indium, tellurium and thallium in the same sample digest of geological materials by atomic-absorption spectroscopy and two-step solvent extraction

    USGS Publications Warehouse

    Hubert, A.E.; Chao, T.T.

    1985-01-01

    A rock, soil, or stream-sediment sample is decomposed with hydrofluoric acid, aqua regia, and hydrobromic acid-bromine solution. Gold, thallium, indium and tellurium are separated and concentrated from the sample digest by a two-step MIBK extraction at two concentrations of hydrobromic add. Gold and thallium are first extracted from 0.1M hydrobromic acid medium, then indium and tellurium are extracted from 3M hydrobromic acid in the presence of ascorbic acid to eliminate iron interference. The elements are then determined by flame atomic-absorption spectrophotometry. The two-step solvent extraction can also be used in conjunction with electrothermal atomic-absorption methods to lower the detection limits for all four metals in geological materials. ?? 1985.

  14. METHOD AND APPARATUS FOR REACTOR SAFETY CONTROL

    DOEpatents

    Huston, N.E.

    1961-06-01

    A self-contained nuclear reactor fuse controlled device tron absorbing material, normally in a compact form but which can be expanded into an extended form presenting a large surface for neutron absorption when triggered by an increase in neutron flux, is described.

  15. Atomizer with liquid spray quenching

    DOEpatents

    Anderson, Iver E.; Osborne, Matthew G.; Terpstra, Robert L.

    1998-04-14

    Method and apparatus for making metallic powder particles wherein a metallic melt is atomized by a rotating disk or other atomizer at an atomizing location in a manner to form molten droplets moving in a direction away from said atomizing location. The atomized droplets pass through a series of thin liquid quenching sheets disposed in succession about the atomizing location with each successive quenching sheet being at an increasing distance from the atomizing location. The atomized droplets are incrementally cooled and optionally passivated as they pass through the series of liquid quenching sheets without distorting the atomized droplets from their generally spherical shape. The atomized, cooled droplets can be received in a chamber having a collection wall disposed outwardly of the series of liquid quenching sheets. A liquid quenchant can be flowed proximate the chamber wall to carry the cooled atomized droplets to a collection chamber where atomized powder particles and the liquid quenchant are separated such that the liquid quenchant can be recycled.

  16. Atomizer with liquid spray quenching

    DOEpatents

    Anderson, I.E.; Osborne, M.G.; Terpstra, R.L.

    1998-04-14

    Method and apparatus are disclosed for making metallic powder particles wherein a metallic melt is atomized by a rotating disk or other atomizer at an atomizing location in a manner to form molten droplets moving in a direction away from said atomizing location. The atomized droplets pass through a series of thin liquid quenching sheets disposed in succession about the atomizing location with each successive quenching sheet being at an increasing distance from the atomizing location. The atomized droplets are incrementally cooled and optionally passivated as they pass through the series of liquid quenching sheets without distorting the atomized droplets from their generally spherical shape. The atomized, cooled droplets can be received in a chamber having a collection wall disposed outwardly of the series of liquid quenching sheets. A liquid quenchant can be flowed proximate the chamber wall to carry the cooled atomized droplets to a collection chamber where atomized powder particles and the liquid quenchant are separated such that the liquid quenchant can be recycled. 6 figs.

  17. Fluorescence detection of white-beam X-ray absorption anisotropy: towards element-sensitive projections of local atomic structure

    PubMed Central

    Korecki, P.; Tolkiehn, M.; Dąbrowski, K. M.; Novikov, D. V.

    2011-01-01

    Projections of the atomic structure around Nb atoms in a LiNbO3 single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using Nb K fluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples. PMID:21997909

  18. Electromagnetically induced transparency and nonlinear pulse propagation in a combined tripod and Λ atom-light coupling scheme

    NASA Astrophysics Data System (ADS)

    Hamedi, H. R.; Ruseckas, J.; Juzeliūnas, G.

    2017-09-01

    We consider propagation of a probe pulse in an atomic medium characterized by a combined tripod and Lambda (Λ) atom-light coupling scheme. The scheme involves three atomic ground states coupled to two excited states by five light fields. It is demonstrated that dark states can be formed for such an atom-light coupling. This is essential for formation of the electromagnetically induced transparency (EIT) and slow light. In the limiting cases the scheme reduces to conventional Λ- or N-type atom-light couplings providing the EIT or absorption, respectively. Thus, the atomic system can experience a transition from the EIT to the absorption by changing the amplitudes or phases of control lasers. Subsequently the scheme is employed to analyze the nonlinear pulse propagation using the coupled Maxwell-Bloch equations. It is shown that a generation of stable slow light optical solitons is possible in such a five-level combined tripod and Λ atomic system.

  19. Method of and apparatus for measuring vapor density

    DOEpatents

    Nelson, Loren D.; Cerni, Todd A.

    1989-01-01

    Apparatus and method determine the concentration of an individual component, such as water vapor, of a multi-component mixture, such as a gaseous mixture for cooling a nuclear reactor. A hygrometer apparatus includes an infrared source for producing a broadband infrared energy beam that includes a strong water vapor absorption band and a weak water vapor absorption region. The beam is chopped to select infrared pulses. A temporally first pulse has a wavelength in the weakly absorbing region, a temporally second pulse has a wavelength in the strong band and a temporally third pulse has a wavlength in the weakly absorbing region. A fourth reference pulse representing background radiation is interposed in such chopped pulses. An indium arsenide infrared sensor is responsive to the pulses for generating an output signal in proportion to: ##EQU1## where N1 is proportional to the transmission through the sample of the first signal, N4 is related to the background radiation, and [K2 (N2-N4)+K3 (N3-N4)] is the time-weighted average of the transmission through the sample of the second and third pulses applicable at the time of the second pulse, with the reference pulse N4 being subtracted in each case to render the ratio independent of variations in the background radiation.

  20. Vacuum Arc Vapor Deposition Method and Apparatus for Applying Identification Symbols to Substrates

    NASA Technical Reports Server (NTRS)

    Schramm, Harry F. (Inventor); Roxby, Donald L. (Inventor); Weeks, Jack L. (Inventor)

    2002-01-01

    An apparatus for applying permanent markings onto products using a Vacuum Arc Vapor Deposition (VAVD) marker by accelerating atoms or molecules from a vaporization source onto a substrate to form human and/or machine-readable part identification marking that can be detected optically or via a sensing device like x-ray, thermal imaging, ultrasound, magneto-optic, micro-power impulse radar, capacitance, or other similar sensing means. The apparatus includes a housing with a nozzle having a marking end. A chamber having an electrode, a vacuum port and a charge is located within the housing. The charge is activated by the electrode in a vacuum environment and deposited onto a substrate at the marking end of the nozzle. The apparatus may be a hand-held device or be disconnected from the handle and mounted to a robot or fixed station.

  1. First-principles calculations of K-shell X-ray absorption spectra for warm dense nitrogen

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Zi; Zhang, Shen; Kang, Wei

    2016-05-15

    X-ray absorption spectrum is a powerful tool for atomic structure detection on warm dense matter. Here, we perform first-principles molecular dynamics and X-ray absorption spectrum calculations on warm dense nitrogen along a Hugoniot curve. From the molecular dynamics trajectory, the detailed atomic structures are examined for each thermodynamical condition. The K-shell X-ray absorption spectrum is calculated, and its changes with temperature and pressure along the Hugoniot curve are discussed. The warm dense nitrogen systems may contain isolated nitrogen atoms, N{sub 2} molecules, and nitrogen clusters, which show quite different contributions to the total X-ray spectrum due to their different electronmore » density of states. The changes of X-ray spectrum along the Hugoniot curve are caused by the different nitrogen structures induced by the temperature and the pressure. Some clear signatures on X-ray spectrum for different thermodynamical conditions are pointed out, which may provide useful data for future X-ray experiments.« less

  2. Analysis of Size Correlations for Microdroplets Produced by Ultrasonic Atomization

    PubMed Central

    Barba, Anna Angela; d'Amore, Matteo

    2013-01-01

    Microencapsulation techniques are widely applied in the field of pharmaceutical production to control drugs release in time and in physiological environments. Ultrasonic-assisted atomization is a new technique to produce microencapsulated systems by a mechanical approach. Interest in this technique is due to the advantages evidenceable (low level of mechanical stress in materials, reduced energy request, reduced apparatuses size) when comparing it to more conventional techniques. In this paper, the groundwork of atomization is introduced, the role of relevant parameters in ultrasonic atomization mechanism is discussed, and correlations to predict droplets size starting from process parameters and material properties are presented and tested. PMID:24501580

  3. Detection of titanium in human tissues after craniofacial surgery.

    PubMed

    Jorgenson, D S; Mayer, M H; Ellenbogen, R G; Centeno, J A; Johnson, F B; Mullick, F G; Manson, P N

    1997-04-01

    Generally, titanium fixation plates are not removed after osteosynthesis, because they have high biocompatability and high corrosion resistance characteristics. Experiments with laboratory animals, and limited studies of analyses of human tissues, have reported evidence of titanium release into local and distant tissues. This study summarizes our results of the analysis of soft tissues for titanium in four patients with titanium microfixation plates. Energy dispersive x-ray analysis, scanning electron microscopy, and electrothermal atomic absorption spectrophotometry were used to detect trace amounts of titanium in surrounding soft tissues. A single metal inclusion was detected by scanning electron microscopy and energy dispersive x-ray analysis in one patient, whereas, electrothermal atomic absorption spectrophotometry analyses revealed titanium present in three of four specimens in levels ranging from 7.92 to 31.8 micrograms/gm of dry tissue. Results from this study revealed trace amounts of titanium in tissues surrounding craniofacial plates. At the atomic level, electrothermal atomic absorption spectrophotometry appears to be a sensitive tool to quantitatively detect ultra-trace amounts of metal in human tissue.

  4. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of chromium in water by graphite furnace atomic absorption spectrophotometry

    USGS Publications Warehouse

    McLain, B.J.

    1993-01-01

    Graphite furnace atomic absorption spectrophotometry is a sensitive, precise, and accurate method for the determination of chromium in natural water samples. The detection limit for this analytical method is 0.4 microg/L with a working linear limit of 25.0 microg/L. The precision at the detection limit ranges from 20 to 57 percent relative standard deviation (RSD) with an improvement to 4.6 percent RSD for concentrations more than 3 microg/L. Accuracy of this method was determined for a variety of reference standards that was representative of the analytical range. The results were within the established standard deviations. Samples were spiked with known concentrations of chromium with recoveries ranging from 84 to 122 percent. In addition, a comparison of data between graphite furnace atomic absorption spectrophotometry and direct-current plasma atomic emission spectrometry resulted in suitable agreement between the two methods, with an average deviation of +/- 2.0 microg/L throughout the analytical range.

  5. Evolution in time of an N-atom system. I. A physical basis set for the projection of the master equation

    NASA Astrophysics Data System (ADS)

    Freedhoff, Helen

    2004-01-01

    We study an aggregate of N identical two-level atoms (TLA’s) coupled by the retarded interatomic interaction, using the Lehmberg-Agarwal master equation. First, we calculate the entangled eigenstates of the system; then, we use these eigenstates as a basis set for the projection of the master equation. We demonstrate that in this basis the equations of motion for the level populations, as well as the expressions for the emission and absorption spectra, assume a simple mathematical structure and allow for a transparent physical interpretation. To illustrate the use of the general theory in emission processes, we study an isosceles triangle of atoms, and present in the long wavelength limit the (cascade) emission spectrum for a hexagon of atoms fully excited at t=0. To illustrate its use for absorption processes, we tabulate (in the same limit) the biexciton absorption frequencies, linewidths, and relative intensities for polygons consisting of N=2,…,9 TLA’s.

  6. Determination of selected elements in whole coal and in coal ash from the eight argonne premium coal samples by atomic absorption spectrometry, atomic emission spectrometry, and ion-selective electrode

    USGS Publications Warehouse

    Doughten, M.W.; Gillison, J.R.

    1990-01-01

    Methods for the determination of 24 elements in whole coal and coal ash by inductively coupled argon plasma-atomic emission spectrometry, flame, graphite furnace, and cold vapor atomic absorption spectrometry, and by ion-selective electrode are described. Coal ashes were analyzed in triplicate to determine the precision of the methods. Results of the analyses of NBS Standard Reference Materials 1633, 1633a, 1632a, and 1635 are reported. Accuracy of the methods is determined by comparison of the analysis of standard reference materials to their certified values as well as other values in the literature.

  7. Two-photon absorption laser-induced fluorescence measurements of atomic nitrogen in a radio-frequency atmospheric-pressure plasma jet

    NASA Astrophysics Data System (ADS)

    Wagenaars, E.; Gans, T.; O'Connell, D.; Niemi, K.

    2012-08-01

    The first direct measurements of atomic nitrogen species in a radio-frequency atmospheric-pressure plasma jet (APPJ) are presented. Atomic nitrogen radicals play a key role in new plasma medicine applications of APPJs. The measurements were performed with a two-photon absorption laser-induced fluorescence diagnostic, using 206.65 nm laser photons for the excitation of ground-state N atoms and observing fluorescence light around 744 nm. The APPJ was run with a helium gas flow of 1 slm and varying small admixtures of molecular nitrogen of 0-0.7 vol%. A maximum in the measured N concentration was observed for an admixture of 0.25 vol% N2.

  8. First-principles studies of a photovoltaic material based on silicon heavily codoped with sulfur and nitrogen

    NASA Astrophysics Data System (ADS)

    Dong, Xiao; Wang, Yongyong; Song, Xiaohui; Yang, Feng

    2018-03-01

    In silicon co-hyperdoped with nitrogen and sulfur, dopant atoms tend to form dimers in the near-equilibrium process. The dimer that contains substitutional N and S atoms has the lowest formation energy and can form an impurity band that overlaps with the conduction band (CB). When separating the two atoms far apart from each other, the impurity band is clearly isolated from the CB and becomes an intermediate band (IB). The sub-band-gap absorption decreases with the decrease in the substitutional atom distance. The sub-band-gap absorption of the material is the combined effect of the configurations with different N-S distances.

  9. Production mechanism of atomic nitrogen in atmospheric pressure pulsed corona discharge measured using two-photon absorption laser-induced fluorescence

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Teramoto, Yoshiyuki; Ono, Ryo; Oda, Tetsuji

    To study the production mechanism of atomic nitrogen, the temporal profile and spatial distribution of atomic nitrogen are measured in atmospheric pressure pulsed positive corona discharge using two-photon absorption laser-induced fluorescence. The absolute atomic nitrogen density in the streamer filaments is estimated from decay rate of atomic nitrogen in N{sub 2} discharge. The results indicate that the absolute atomic nitrogen density is approximately constant against discharge energy. When the discharge voltage is 21.5 kV, production yield of atomic nitrogen produced by an N{sub 2} discharge pulse is estimated to be 2.9 - 9.8 Multiplication-Sign 10{sup 13} atoms and the energymore » efficiency of atomic nitrogen production is estimated to be about 1.8 - 6.1 Multiplication-Sign 10{sup 16} atoms/J. The energy efficiency of atomic nitrogen production in N{sub 2} discharge is constant against the discharge energy, while that in N{sub 2}/O{sub 2} discharge increases with discharge energy. In the N{sub 2}/O{sub 2} discharge, two-step process of N{sub 2} dissociation plays significant role for atomic nitrogen production.« less

  10. U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION, AND MAINTENANCE OF THE PERKIN-ELMER 5100 PC ATOMIC ABSORPTION SPECTROMETER (BCO-L-5.1)

    EPA Science Inventory

    The purpose of this SOP is to outline the start-up, calibration, operation, and maintenance procedures for the Perkin-Elmer 5100 PC Atomic Absorption Spectrophotometer (PE 5100). These procedures are used for the determination of the target trace metal, as in soil, house dust, f...

  11. Analysis of an Air Conditioning Coolant Solution for Metal Contamination Using Atomic Absorption Spectroscopy: An Undergraduate Instrumental Analysis Exercise Simulating an Industrial Assignment

    ERIC Educational Resources Information Center

    Baird, Michael J.

    2004-01-01

    A real-life analytical assignment is presented to students, who had to examine an air conditioning coolant solution for metal contamination using an atomic absorption spectroscopy (AAS). This hands-on access to a real problem exposed the undergraduate students to the mechanism of AAS, and promoted participation in a simulated industrial activity.

  12. Determination of Pb in Biological Samples by Graphite Furnace Atomic Absorption Spectrophotometry: An Exercise in Common Interferences and Fundamental Practices in Trace Element Determination

    ERIC Educational Resources Information Center

    Spudich, Thomas M.; Herrmann, Jennifer K.; Fietkau, Ronald; Edwards, Grant A.

    2004-01-01

    An experiment is conducted to ascertain trace-level Pb in samples of bovine liver or muscle by applying graphite furnace atomic absorption spectrophotometry (GFAAS). The primary objective is to display the effects of physical and spectral intrusions in determining trace elements, and project the usual methods employed to minimize accuracy errors…

  13. Correlation between Wavelength Dispersive X-ray Fluorescence (WDXRF) analysis of hardened concrete for chlorides vs. Atomic Absorption (AA) analysis in accordance with AASHTO T- 260; sampling and testing for chloride ion in concrete and concrete raw mater

    DOT National Transportation Integrated Search

    2014-04-01

    A correlation between Wavelength Dispersive X-ray Fluorescence(WDXRF) analysis of Hardened : Concrete for Chlorides and Atomic Absorption (AA) analysis (current method AASHTO T-260, procedure B) has been : found and a new method of analysis has been ...

  14. Identifying Student and Teacher Difficulties in Interpreting Atomic Spectra Using a Quantum Model of Emission and Absorption of Radiation

    ERIC Educational Resources Information Center

    Savall-Alemany, Francisco; Domènech-Blanco, Josep Lluís; Guisasola, Jenaro; Martínez-Torregrosa, Joaquín

    2016-01-01

    Our study sets out to identify the difficulties that high school students, teachers, and university students encounter when trying to explain atomic spectra. To do so, we identify the key concepts that any quantum model for the emission and absorption of electromagnetic radiation must include to account for the gas spectra and we then design two…

  15. Determination of Fe Content of Some Food Items by Flame Atomic Absorption Spectroscopy (FAAS): A Guided-Inquiry Learning Experience in Instrumental Analysis Laboratory

    ERIC Educational Resources Information Center

    Fakayode, Sayo O.; King, Angela G.; Yakubu, Mamudu; Mohammed, Abdul K.; Pollard, David A.

    2012-01-01

    This article presents a guided-inquiry (GI) hands-on determination of Fe in food samples including plantains, spinach, lima beans, oatmeal, Frosted Flakes cereal (generic), tilapia fish, and chicken using flame atomic absorption spectroscopy (FAAS). The utility of the GI experiment, which is part of an instrumental analysis laboratory course,…

  16. Infrared reduction, an efficient method to control the non-linear optical property of graphene oxide in femtosecond regime

    NASA Astrophysics Data System (ADS)

    Bhattacharya, S.; Maiti, R.; Saha, S.; Das, A. C.; Mondal, S.; Ray, S. K.; Bhaktha, S. B. N.; Datta, P. K.

    2016-04-01

    Graphene Oxide (GO) has been prepared by modified Hummers method and it has been reduced using an IR bulb (800-2000 nm). Both as grown GO and reduced graphene oxide (RGO) have been characterized using Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Raman spectra shows well documented Dband and G-band for both the samples while blue shift of G-band confirms chemical functionalization of graphene with different oxygen functional group. The XPS result shows that the as-prepared GO contains 52% of sp2 hybridized carbon due to the C=C bonds and 33% of carbon atoms due to the C-O bonds. As for RGO, increment of the atomic % of the sp2 hybridized carbon atom to 83% and rapid decrease in atomic % of C=O bonds confirm an efficient reduction with infrared radiation. UV-Visible absorption spectrum also confirms increment of conjugation with increased reduction. Non-linear optical properties of both GO and RGO are measured using single beam open aperture Z-Scan technique in femtosecond regime. Intensity dependent nonlinear phenomena are observed. Depending upon the intensity, both saturable absorption and two photon absorption contribute to the non-linearity of both the samples. Saturation dominates at low intensity (~ 127 GW/cm2) while two photon absorption become prominent at higher intensities (from 217 GW/cm2 to 302 GW/cm2). We have calculated the two-photon absorption co-efficient and saturation intensity for both the samples. The value of two photon absorption co-efficient (for GO~ 0.0022-0.0037 cm/GW and for RGO~ 0.0128-0.0143 cm/GW) and the saturation intensity (for GO~57 GW/cm2 and for RGO~ 194GW/cm2) is increased with reduction. Increase in two photon absorption coefficient with increasing intensity can also suggest that there may be multi-photon absorption is taking place.

  17. Theory of fiber-optic, evanescent-wave spectroscopy and sensors

    NASA Astrophysics Data System (ADS)

    Messica, A.; Greenstein, A.; Katzir, A.

    1996-05-01

    A general theory for fiber-optic, evanescent-wave spectroscopy and sensors is presented for straight, uncladded, step-index, multimode fibers. A three-dimensional model is formulated within the framework of geometric optics. The model includes various launching conditions, input and output end-face Fresnel transmission losses, multiple Fresnel reflections, bulk absorption, and evanescent-wave absorption. An evanescent-wave sensor response is analyzed as a function of externally controlled parameters such as coupling angle, f number, fiber length, and diameter. Conclusions are drawn for several experimental apparatuses.

  18. Methods and apparatus for producing and storing positrons and protons

    DOEpatents

    Akers, Douglas W [Idaho Falls, ID

    2010-07-06

    Apparatus for producing and storing positrons may include a trap that defines an interior chamber therein and that contains an electric field and a magnetic field. The trap may further include a source material that includes atoms that, when activated by photon bombardment, become positron emitters to produce positrons. The trap may also include a moderator positioned adjacent the source material. A photon source is positioned adjacent the trap so that photons produced by the photon source bombard the source material to produce the positron emitters. Positrons from the positron emitters and moderated positrons from the moderator are confined within the interior chamber of the trap by the electric and magnetic fields. Apparatus for producing and storing protons are also disclosed.

  19. LIQUID TARGET

    DOEpatents

    Martin, M.D.; Salsig, W.W. Jr.

    1959-01-13

    A liquid handling apparatus is presented for a liquid material which is to be irradiated. The apparatus consists essentially of a reservoir for the liquid, a target element, a drain tank and a drain lock chamber. The target is in the form of a looped tube, the upper end of which is adapted to be disposed in a beam of atomic particles. The lower end of the target tube is in communication with the liquid in the reservoir and a means is provided to continuously circulate the liquid material to be irradiated through the target tube. Means to heat the reservoir tank is provided in the event that a metal is to be used as the target material. The apparatus is provided with suitable valves and shielding to provide maximum safety in operation.

  20. Analytical characteristics of a continuum-source tungsten coil atomic absorption spectrometer.

    PubMed

    Rust, Jennifer A; Nóbrega, Joaquim A; Calloway, Clifton P; Jones, Bradley T

    2005-08-01

    A continuum-source tungsten coil electrothermal atomic absorption spectrometer has been assembled, evaluated, and employed in four different applications. The instrument consists of a xenon arc lamp light source, a tungsten coil atomizer, a Czerny-Turner high resolution monochromator, and a linear photodiode array detector. This instrument provides simultaneous multi-element analyses across a 4 nm spectral window with a resolution of 0.024 nm. Such a device might be useful in many different types of analyses. To demonstrate this broad appeal, four very different applications have been evaluated. First of all, the temperature of the gas phase was measured during the atomization cycle of the tungsten coil, using tin as a thermometric element. Secondly, a summation approach for two absorption lines for aluminum falling within the same spectral window (305.5-309.5 nm) was evaluated. This approach improves the sensitivity without requiring any additional preconcentration steps. The third application describes a background subtraction technique, as it is applied to the analysis of an oil emulsion sample. Finally, interference effects caused by Na on the atomization of Pb were studied. The simultaneous measurements of Pb and Na suggests that negative interference arises at least partially from competition between Pb and Na atoms for H2 in the gas phase.

  1. Determination of Cd in urine by cloud point extraction-tungsten coil atomic absorption spectrometry.

    PubMed

    Donati, George L; Pharr, Kathryn E; Calloway, Clifton P; Nóbrega, Joaquim A; Jones, Bradley T

    2008-09-15

    Cadmium concentrations in human urine are typically at or below the 1 microgL(-1) level, so only a handful of techniques may be appropriate for this application. These include sophisticated methods such as graphite furnace atomic absorption spectrometry and inductively coupled plasma mass spectrometry. While tungsten coil atomic absorption spectrometry is a simpler and less expensive technique, its practical detection limits often prohibit the detection of Cd in normal urine samples. In addition, the nature of the urine matrix often necessitates accurate background correction techniques, which would add expense and complexity to the tungsten coil instrument. This manuscript describes a cloud point extraction method that reduces matrix interference while preconcentrating Cd by a factor of 15. Ammonium pyrrolidinedithiocarbamate and Triton X-114 are used as complexing agent and surfactant, respectively, in the extraction procedure. Triton X-114 forms an extractant coacervate surfactant-rich phase that is denser than water, so the aqueous supernatant is easily removed leaving the metal-containing surfactant layer intact. A 25 microL aliquot of this preconcentrated sample is placed directly onto the tungsten coil for analysis. The cloud point extraction procedure allows for simple background correction based either on the measurement of absorption at a nearby wavelength, or measurement of absorption at a time in the atomization step immediately prior to the onset of the Cd signal. Seven human urine samples are analyzed by this technique and the results are compared to those found by the inductively coupled plasma mass spectrometry analysis of the same samples performed at a different institution. The limit of detection for Cd in urine is 5 ngL(-1) for cloud point extraction tungsten coil atomic absorption spectrometry. The accuracy of the method is determined with a standard reference material (toxic metals in freeze-dried urine) and the determined values agree with the reported levels at the 95% confidence level.

  2. Isoelectric focusing in space

    NASA Technical Reports Server (NTRS)

    Bier, M.; Egen, N. B.; Mosher, R. A.; Twitty, G. E.

    1982-01-01

    The potential of space electrophoresis is conditioned by the fact that all electrophoretic techniques require the suppression of gravity-caused convection. Isoelectric focusing (IEF) is a powerful variant of electrophoresis, in which amphoteric substances are separated in a pH gradient according to their isoelectric points. A new apparatus for large scale IEF, utilizing a recycling principle, has been developed. In the ground-based prototype, laminar flow is provided by a series of parallel filter elements. The operation of the apparatus is monitored by an automated array of pH and ultraviolet absorption sensors under control of a desk-top computer. The apparatus has proven to be useful for the purification of a variety of enzymes, snake venom proteins, peptide hormones, and other biologicals, including interferon produced by genetic engineering techniques. In planning for a possible space apparatus, a crucial question regarding electroosmosis needs to be addressed To solve this problem, simple focusing test modules are planned for inclusion in an early Shuttle flight.

  3. Absorption cross sections of some atmospheric molecules for resonantly scattered O I 1304-A radiation

    NASA Technical Reports Server (NTRS)

    Starr, W. L.

    1976-01-01

    Absorption cross sections for O2, N2, CO2, CH4, N2O, and CO have been measured at each of the lines of the atomic oxygen triplet at 1302, 1305, and 1306 A. Radiation resonantly scattered from oxygen atoms at a temperature of about 300 K was used for the line source. Absorber temperatures were also near 300 K. Direct application of the Lambert-Beer absorption equation yielded pressure-dependent cross sections for carbon monoxide at each line of the O I triplet. Reasons for this apparent dependence are presented and discussed.

  4. Direct sampling graphite furnace atomic absorption spectrometry - feasibility of Na and K determination in desalted crude oil

    NASA Astrophysics Data System (ADS)

    Seeger, Tassia S.; Machado, Eduarda Q.; Flores, Erico M. M.; Mello, Paola A.; Duarte, Fabio A.

    2018-03-01

    In this study, Na and K were determined in desalted crude oil by direct sampling graphite furnace atomic absorption spectrometry (DS-GF AAS), with the use of a Zeeman-effect background correction system with variable magnetic field. The analysis was performed in low and high sensitivity conditions. Sodium determination was performed in two low-sensitivity conditions: 1) main absorption line (589.0 nm), gas stop flow during the atomization step and 3-field dynamic mode (0.6-0.8 T); and 2) secondary absorption line (330.3 nm), gas stop flow during the atomization and 2-field mode (0.8 T). In K determination, some parameters, such as high-sensitivity mode, main absorption line (766.5 nm), gas stop flow during the atomization and 2-field mode (0.8 T), were used. Suitability of chemical modifiers, such as Pd and W-Ir was also evaluated. The heating program for Na and K was based on the pyrolysis and atomization curves. Calibration was performed by aqueous standards. Accuracy was evaluated by the analysis of Green Petroleum Coke (SRM NIST 2718) and Trace Elements in Fuel Oil (SRM NIST 1634c). Recovery tests were also performed and results were compared with those obtained by GF AAS after crude oil digestion by microwave-assisted digestion. The characteristic mass of Na was 17.1 pg and 0.46 ng in conditions 1 and 2, respectively, while the one of K was 1.4 pg. Limits of detection and quantification by DS-GF AAS were 30 and 40 ng g-1 for Na and 3.2 and 4.2 ng g-1 for K, respectively. Sodium and K were determined in three crude oil samples with API density ranging from 20.9 to 28.0. Sodium and K concentration ranged from 1.5 to 73 μg g-1 and from 23 to 522 ng g-1, respectively.

  5. Kinematic cooling of molecules in a magneto-optical trap

    NASA Astrophysics Data System (ADS)

    Takase, Ken; Chandler, David W.; Strecker, Kevin E.

    2008-05-01

    We will present our current progress on a new experimental technique aimed at slowing and cooling hot molecules using a single collision with magneto-optically trapped atoms. Kinematic cooling, unlike buffer gas and sympathetic cooling, relies only on a single collision between the molecule and atom to stop the molecule in the laboratory frame. This technique has recently been demonstrated in a crossed atomic and molecular beam machine to produce 35mK samples of nitric oxide via a single collision with argon [1]. In this technique we replace the atomic beam with a sample magneto-optically trapped atoms. We are currently designing and building a new apparatus to attempt these experiments. [1] Kevin E. Strecker and David W. Chandler (to be published)

  6. An ultracold potassium Rydberg source for experiments in quantum optics and many-body physics

    NASA Astrophysics Data System (ADS)

    Conover, Charles; Dupre, Pamela; Tong, Ai Phuong; Sanon, Carlvin; Clarke, Kevin; Doolittle, Brian; Louria, Stephen; Adamson, Philip

    2017-04-01

    We report on the development of an apparatus for the study of quantum dynamics of Rydberg atoms of potassium. Samples of Rydberg atoms at 1 mK and varying density are excited in a magneto-optical trap of 107 K-39 atoms. The atoms are excited to Rydberg states in a steps from 4s to 5p and from 5p to ns and nd states using stabilized external-cavity diode lasers at 405 nm and 980 nm. Selective field ionization and detection with microchannel plates provides a platform for spectroscopic measurements in potassium, exploration of multiphoton processes, and experiments on cold atom collisions. This research was supported by the National Science Foundation under Grant PHY-1126599.

  7. Determination of tetraalkyllead compounds in gasoline by liquid chromatography-atomic absorption spectrometry

    USGS Publications Warehouse

    Messman, J.D.; Rains, T.C.

    1981-01-01

    A liquid chromatography-atomic absorption spectrometry (LC-AAS) hybrid analytical technique is presented for metal speciation measurements on complex liquid samples. The versatility and inherent metal selectivity of the technique are Illustrated by the rapid determination of five tetraalkyllead compounds in commercial gasoline. Separation of the individual tetraalkyllead species is achieved by reversed-phase liquid chromatography using an acetonitrile/water mobile phase. The effluent from the liquid Chromatograph Is introduced directly into the aspiration uptake capillary of the nebulizer of an air/acetylene flame atomic absorption spectrometer. Spectral interferences due to coeluting hydrocarbon matrix constituents were not observed at the 283.3-nm resonance line of lead used for analysis. Detection limits of this LC-AAS hydrid analytical technique, based on a 20-??L injection, are approximately 10 ng Pb for each tetraalkyllead compound.

  8. Mass energy-absorption coefficients and average atomic energy-absorption cross-sections for amino acids in the energy range 0.122-1.330 MeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    More, Chaitali V., E-mail: chaitalimore89@gmail.com; Lokhande, Rajkumar M.; Pawar, Pravina P., E-mail: pravinapawar4@gmail.com

    Mass attenuation coefficients of amino acids such as n-acetyl-l-tryptophan, n-acetyl-l-tyrosine and d-tryptophan were measured in the energy range 0.122-1.330 MeV. NaI (Tl) scintillation detection system was used to detect gamma rays with a resolution of 8.2% at 0.662 MeV. The measured attenuation coefficient values were then used to determine the mass energy-absorption coefficients (σ{sub a,en}) and average atomic energy-absorption cross sections (μ{sub en}/ρ) of the amino acids. Theoretical values were calculated based on XCOM data. Theoretical and experimental values are found to be in good agreement.

  9. Lithogeochemistry of mineralized and altered rock samples from the northern Talkeetna Mountains, south-central Alaska

    USGS Publications Warehouse

    Light, Thomas D.; Schmidt, Jeanine M.

    2011-01-01

    Mineralized and altered rock samples collected from the northern Talkeetna Mountains, Alaska, were analyzed by two different inductively coupled plasma atomic-emission spectrometry (ICP-AES) methods for as many as 44 elements; by fire assay and either direct-coupled plasma (DCP) or atomic absorption spectrophotometry (AAS) for gold (Au); by cold vapor atomic absorption (CVAA) for mercury (Hg); and by irradiated neutron activation analysis (INAA) for tungsten (W). The analytical results showed that some samples contain high values of multiple elements and may be potential indicators of hydrothermal mineralization in the area.

  10. Structure of Co-Doped Alq3 thin films investigated by grazing incidence X-ray absorption fine structure and Fourier transform infrared spectroscopy.

    PubMed

    Lin, Liang; Pang, Zhiyong; Fang, Shaojie; Wang, Fenggong; Song, Shumei; Huang, Yuying; Wei, Xiangjun; Yu, Haisheng; Han, Shenghao

    2011-02-10

    The structural properties of Co-doped tris(8-hydroxyquinoline)aluminum (Alq(3)) have been studied by grazing incidence X-ray absorption fine structure (GIXAFS) and Fourier transform infrared spectroscopy (FTIR). GIXAFS analysis suggests that there are multivalent Co-Alq(3) complexes and the doped Co atoms tend to locate at the attraction center with respect to N and O atoms and bond with them. The FTIR spectra indicate that the Co atoms interact with the meridional (mer) isomer of Alq(3) rather than forming inorganic compounds.

  11. Manganese dioxide causes spurious gold values in flame atomic-absorption readings from HBr-Br2 digestions

    USGS Publications Warehouse

    Campbell, W.L.

    1981-01-01

    False readings, apparently caused by the presence of high concentrations of manganese dioxide, have been observed in our current flame atomic-absorption procedure for the determination of gold. After a hydrobromic acid (HBr)-bromine (Br2) leach, simply heating the sample to boiling to remove excess Br2 prior to extraction with methyl-isobutyl-ketone (MIBK) eliminates these false readings. ?? 1981.

  12. Rapid determination of nanogram amounts of tellurium in silicate rocks

    USGS Publications Warehouse

    Greenland, L.P.; Campbell, E.Y.

    1976-01-01

    A hydride-generation flameless atomic-absorption technique is used to determine as little as 5 ng g-1 tellurium in 0.25 g of silicate rock. After acid decomposition of the sample, tellurium hydride is generated with sodium borohydride and the vapor passed directly to a resistance-heated quartz cell mounted in an atomic-absorption spectrophotometer. Analyses of 11 U.S. Geological Survey standard rocks are presented. ?? 1976.

  13. Attosecond XUV absorption spectroscopy of doubly excited states in helium atoms dressed by a time-delayed femtosecond infrared laser

    NASA Astrophysics Data System (ADS)

    Yang, Z. Q.; Ye, D. F.; Ding, Thomas; Pfeifer, Thomas; Fu, L. B.

    2015-01-01

    In the present paper, we investigate the time-resolved transient absorption spectroscopy of doubly excited states of helium atoms by solving the time-dependent two-electron Schrödinger equation numerically based on a one-dimensional model. The helium atoms are subjected to an extreme ultraviolet (XUV) attosecond pulse and a time-delayed infrared (IR) few-cycle laser pulse. A superposition of doubly excited states populated by the XUV pulse is identified, which interferes with the direct ionization pathway leading to Fano resonance profiles in the photoabsorption spectrum. In the presence of an IR laser, however, the Fano line profiles are strongly modified: A shifting, splitting, and broadening of the original absorption lines is observed when the XUV attosecond pulse and infrared few-cycle laser pulse overlap in time, which is in good agreement with recent experimental results. At certain time delays, we observe symmetric Lorentz, inverted Fano profiles, and even negative absorption cross sections indicating that the XUV light can be amplified during the interaction with atoms. We further prove that the above pictures are general for different doubly excited states by suitably varying the frequency of the IR field to coherently couple the corresponding states.

  14. [Evaluation of uncertainty for determination of tin and its compounds in air of workplace by flame atomic absorption spectrometry].

    PubMed

    Wei, Qiuning; Wei, Yuan; Liu, Fangfang; Ding, Yalei

    2015-10-01

    To investigate the method for uncertainty evaluation of determination of tin and its compounds in the air of workplace by flame atomic absorption spectrometry. The national occupational health standards, GBZ/T160.28-2004 and JJF1059-1999, were used to build a mathematical model of determination of tin and its compounds in the air of workplace and to calculate the components of uncertainty. In determination of tin and its compounds in the air of workplace using flame atomic absorption spectrometry, the uncertainty for the concentration of the standard solution, atomic absorption spectrophotometer, sample digestion, parallel determination, least square fitting of the calibration curve, and sample collection was 0.436%, 0.13%, 1.07%, 1.65%, 3.05%, and 2.89%, respectively. The combined uncertainty was 9.3%.The concentration of tin in the test sample was 0.132 mg/m³, and the expanded uncertainty for the measurement was 0.012 mg/m³ (K=2). The dominant uncertainty for determination of tin and its compounds in the air of workplace comes from least squares fitting of the calibration curve and sample collection. Quality control should be improved in the process of calibration curve fitting and sample collection.

  15. Path integral Monte Carlo study on the structure and absorption spectra of alkali atoms (Li, Na, K) attached to superfluid helium clusters

    NASA Astrophysics Data System (ADS)

    Nakayama, Akira; Yamashita, Koichi

    2001-01-01

    Path integral Monte Carlo calculations have been performed to investigate the microscopic structure and thermodynamic properties of the AkṡHeN (Ak=Li, Na, K,N⩽300) clusters at T=0.5 K. Absorption spectra which correspond to the 2P←2S transitions of alkali atoms are also calculated within a pairwise additive model, which employs diatomic Ak-He potential energy curves. The size dependences of the cluster structure and absorption spectra that show the influence of the helium cluster environment are examined in detail. It is found that alkali atoms are trapped in a dimple on the helium cluster's surface and that, from the asymptotic behavior, the AkṡHe300 cluster, at least semiquantitatively, mimics the local structure of experimentally produced large helium clusters in the vicinity of alkali atoms. We have successfully reproduced the overall shapes of the spectra and explained their features from a static and structural point of view. The positions, relative intensities, and line widths of the absorption maxima are calculated to be in moderate agreement with experiments [F. Stienkemeier, J. Higgins, C. Callegari, S. I. Kanorsky, W. E. Ernst, and G. Scoles, Z. Phys. D 38, 253 (1996)].

  16. In situ calibration of inductively coupled plasma-atomic emission and mass spectroscopy

    DOEpatents

    Braymen, S.D.

    1996-06-11

    A method and apparatus are disclosed for in situ addition calibration of an inductively coupled plasma atomic emission spectrometer or mass spectrometer using a precision gas metering valve to introduce a volatile calibration gas of an element of interest directly into an aerosol particle stream. The present in situ calibration technique is suitable for various remote, on-site sampling systems such as laser ablation or nebulization. 5 figs.

  17. Cluster generator

    DOEpatents

    Donchev, Todor I [Urbana, IL; Petrov, Ivan G [Champaign, IL

    2011-05-31

    Described herein is an apparatus and a method for producing atom clusters based on a gas discharge within a hollow cathode. The hollow cathode includes one or more walls. The one or more walls define a sputtering chamber within the hollow cathode and include a material to be sputtered. A hollow anode is positioned at an end of the sputtering chamber, and atom clusters are formed when a gas discharge is generated between the hollow anode and the hollow cathode.

  18. Ignition and combustion characteristics of metallized propellants

    NASA Technical Reports Server (NTRS)

    Mueller, D. C.; Turns, Stephen R.

    1992-01-01

    During this reporting period, theoretical work on the secondary atomization process was continued and the experimental apparatus was improved. A one-dimensional model of a rocket combustor, incorporating multiple droplet size classes, slurry combustion, secondary atomization, radiation heat transfer, and two-phase slip between slurry droplets and the gas flow was derived and a computer code was written to implement this model. The STANJAN chemical equilibrium solver was coupled with this code to yield gas temperature, density, and composition as functions of axial location. Preliminary results indicate that the model is performing correctly, given current model assumptions. Radiation heat transfer in the combustion chamber is treated as an optically-thick participating media problem requiring a solution of the radiative transfer equation. A cylindrical P sub 1 approximation was employed to yield an analytical expression for chamber-wall heat flux at each axial location. The code exercised to determine the effects of secondary atomization intensity, defined as the number of secondary drops produced per initial drop, on chamber burnout distance and final Al2O3 agglomerate diameter. These results indicate that only weak secondary atomization is required to significantly reduce these two parameters. Stronger atomization intensities were found to yield decreasing marginal benefits. The experimental apparatus was improved to reduce building vibration effects on the optical system alignment. This was accomplished by mounting the burner and the transmitting/receiving optics on a single frame supported by vibration-isolation legs. Calibration and shakedown tests indicate that vibration problems were eliminated and that the system is performing correctly.

  19. The Effects of Electromagnetic Fields on The Nervous System,

    DTIC Science & Technology

    Superior Cervical Ganglia: Design of Waveguide Apparatus, and Calculation of Specific Absorption Rate; Effects of Electromagnetic Fields on Muscle ... Contraction ; Effects of Electromagnetic Fields on Auditory System: Effect of Noise Masking on Threshold of Evoked Auditory Responses, Microwave-induced Cochlear Microphonics in Guinea Pigs.

  20. Operation and testing of Mark 10 Mod 3 underwater breathing apparatus

    NASA Technical Reports Server (NTRS)

    Milwee, W. I., Jr.

    1972-01-01

    Performance tests on a closed circuit, mixed gas underwater breathing apparatus are reported. The equipment is designed to provide a minimum diving duration of four hours at 1500 ft below sea surface; it senses oxygen partial pressure in the breathing gas mix and controls oxygen content of the breathing gas within narrow limits about a preset value. The breathing circuit subsystem provides respirable gas to the diver and removes carbon dioxide and moisture from the expired gas. Test results indicate undesirable variations in oxygen partial pressure with oxygen addition and insufficient carbon dioxide absorption.

  1. Apparatus and method for transient thermal infrared spectrometry

    DOEpatents

    McClelland, John F.; Jones, Roger W.

    1991-12-03

    A method and apparatus for enabling analysis of a material (16, 42) by applying a cooling medium (20, 54) to cool a thin surface layer portion of the material and to transiently generate a temperature differential between the thin surface layer portion and the lower portion of the material sufficient to alter the thermal infrared emission spectrum of the material from the black-body thermal infrared emission spectrum of the material. The altered thermal infrared emission spectrum of the material is detected by a spectrometer/detector (28, 50) while the altered thermal infrared emission spectrum is sufficiently free of self-absorption by the material of the emitted infrared radiation. The detection is effected prior to the temperature differential propagating into the lower portion of the material to an extent such that the altered thermal infrared emission spectrum is no longer sufficiently free of self-absorption by the material of emitted infrared radiation, so that the detected altered thermal infrared emission spectrum is indicative of the characteristics relating to the molecular composition of the material.

  2. Separation, identification and quantification of carotenoids and chlorophylls in dietary supplements containing Chlorella vulgaris and Spirulina platensis using High Performance Thin Layer Chromatography.

    PubMed

    Hynstova, Veronika; Sterbova, Dagmar; Klejdus, Borivoj; Hedbavny, Josef; Huska, Dalibor; Adam, Vojtech

    2018-01-30

    In this study, 14 commercial products (dietary supplements) containing alga Chlorella vulgaris and cyanobacteria Spirulina platensis, originated from China and Japan, were analysed. UV-vis spectrophotometric method was applied for rapid determination of chlorophylls, carotenoids and pheophytins; as degradation products of chlorophylls. High Performance Thin-Layer Chromatography (HPTLC) was used for effective separation of these compounds, and also Atomic Absorption Spectrometry for determination of heavy metals as indicator of environmental pollution. Based on the results obtained from UV-vis spectrophotometric determination of photosynthetic pigments (chlorophylls and carotenoids), it was confirmed that Chlorella vulgaris contains more of all these pigments compared to the cyanobacteria Spirulina platensis. The fastest mobility compound identified in Chlorella vulgaris and Spirulina platensis using HPTLC method was β-carotene. Spectral analysis and standard calibration curve method were used for identification and quantification of separated substances on Thin-Layer Chromatographic plate. Quantification of copper (Cu 2+ , at 324.7 nm) and zinc (Zn 2+ , at 213.9nm) was performed using Flame Atomic Absorption Spectrometry with air-acetylene flame atomization. Quantification of cadmium (Cd 2+ , at 228.8 nm), nickel (Ni 2+ , at 232.0nm) and lead (Pb 2+ , at 283.3nm) by Electrothermal Graphite Furnace Atomic Absorption Spectrometry; and quantification of mercury (Hg 2+ , at 254nm) by Cold Vapour Atomic Absorption Spectrometry. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Tuning optical properties of magic number cluster (SiO2)4O2H4 by substitutional bonding with gold atoms.

    PubMed

    Cai, Xiulong; Zhang, Peng; Ma, Liuxue; Zhang, Wenxian; Ning, Xijing; Zhao, Li; Zhuang, Jun

    2009-04-30

    By bonding gold atoms to the magic number cluster (SiO(2))(4)O(2)H(4), two groups of Au-adsorbed shell-like clusters Au(n)(SiO(2))(4)O(2)H(4-n) (n = 1-4) and Au(n)(SiO(2))(4)O(2) (n = 5-8) were obtained, and their spectral properties were studied. The ground-state structures of these clusters were optimized by density functional theory, and the results show that in despite of the different numbers and types of the adsorbed Au atoms, the cluster core (SiO(2))(4)O(2) of T(d) point-group symmetry keeps almost unchanged. The absorption spectra were obtained by time-dependent density functional theory. From one group to the other, an extension of absorption wavelength from the UV-visible to the NIR region was observed, and in each group the absorption strengths vary linearly with the number of Au atoms. These features indicate their advantages for exploring novel materials with easily controlled tunable optical properties. Furthermore, due to the weak electronic charge transfer between the Au atoms, the clusters containing Au(2) dimers, especially Au(8)(SiO(2))(4)O(2), absorb strongly NIR light at 900 approximately 1200 nm. Such strong absorption suggests potential applications of these shell-like clusters in tumor cells thermal therapy, like the gold-coated silica nanoshells with larger sizes.

  4. Optimization of electrothermal atomization parameters for simultaneous multielement atomic absorption spectrometry

    USGS Publications Warehouse

    Harnly, J.M.; Kane, J.S.

    1984-01-01

    The effect of the acid matrix, the measurement mode (height or area), the atomizer surface (unpyrolyzed and pyrolyzed graphite), the atomization mode (from the wall or from a platform), and the atomization temperature on the simultaneous electrothermal atomization of Co, Cr, Cu, Fe, Mn, Mo, Ni, V, and Zn was examined. The 5% HNO3 matrix gave rise to severe irreproducibility using a pyrolyzed tube unless the tube was properly "prepared". The 5% HCl matrix did not exhibit this problem, and no problems were observed with either matrix using an unpyrolized tube or a pyrolyzed platform. The 5% HCl matrix gave better sensitivities with a pyrolyzed tube but the two matrices were comparable for atomization from a platform. If Mo and V are to be analyzed with the other seven elements, a high atomization temperature (2700??C or greater) is necessary regardless of the matrix, the measurement mode, the atomization mode, or the atomizer surface. Simultaneous detection limits (peak height with pyrolyzed tube atomization) were comparable to those of conventional atomic absorption spectrometry using electrothermal atomization above 280 nm. Accuracies and precisions of ??10-15% were found in the 10 to 120 ng mL-1 range for the analysis of NBS acidified water standards.

  5. Determination of trace elements in metals and alloys by atomic-absorption spectroscopy using an induction-heated graphite well furnace as atom source.

    PubMed

    Headridge, J B; Smith, D R

    1972-07-01

    An induction-heated graphite furnace, coupled to a Unicam SP 90 atomic-absorption spectrometer, is described for the direct determination of trace elements in metals and alloys. The furnace is capable of operation at temperatures up to 2400 degrees , and has been used to obtain calibration graphs for the determination of ppm quantities of bismuth in lead-base alloys, cast irons and stainless steels, and for the determination of cadmium at the ppm level in zinc-base alloys. Milligram samples of the alloys were atomized directly. Calibration graphs for the determination of the elements in solutions were obtained for comparison. The accuracy and precision of the determination are presented and discussed.

  6. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yamazaki, M.; Kasai, Y.; Oishi, K.

    An (e,2e) apparatus for electron momentum spectroscopy (EMS) has been developed, which employs an ultrashort-pulsed incident electron beam with a repetition rate of 5 kHz and a pulse duration in the order of a picosecond. Its instrumental design and technical details are reported, involving demonstration of a new method for finding time-zero. Furthermore, EMS data for the neutral Ne atom in the ground state measured by using the pulsed electron beam are presented to illustrate the potential abilities of the apparatus for ultrafast molecular dynamics, such as by combining EMS with the pump-and-probe technique.

  7. Method and apparatus for reducing coherence of high-power laser beams

    DOEpatents

    Moncur, Norman K.; Mayer, Frederick J.

    1978-01-01

    Method and apparatus for reducing the coherence and for smoothing the power density profile of a collimated high-power laser beam in which the beam is focused at a point on the surface of a target fabricated of material having a low atomic number. The initial portion of the focused beam heats the material to form a hot reflective plasma at the material surface. The remaining, major portion of the focused beam is reflected by the plasma and recollected to form a collimated beam having reduced beam coherence.

  8. Nitrogen fixation apparatus

    DOEpatents

    Chen, Hao-Lin

    1984-01-01

    A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O.sub.2 /cm promotes the formation of vibrationally excited N.sub.2. Atomic oxygen interacts with vibrationally excited N.sub.2 at a much quicker rate than unexcited N.sub.2, greatly improving the rate at which NO is formed.

  9. Nitrogen fixation method and apparatus

    DOEpatents

    Chen, Hao-Lin

    1983-01-01

    A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O.sub.2 /cm promotes the formation of vibrationally excited N.sub.2. Atomic oxygen interacts with vibrationally excited N.sub.2 at a much quicker rate than unexcited N.sub.2, greatly improving the rate at which NO is formed.

  10. Nitrogen fixation method and apparatus

    DOEpatents

    Chen, H.L.

    1983-08-16

    A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O[sub 2]/cm promotes the formation of vibrationally excited N[sub 2]. Atomic oxygen interacts with vibrationally excited N[sub 2] at a much quicker rate than unexcited N[sub 2], greatly improving the rate at which NO is formed. 1 fig.

  11. Materials selection for long life in low earth orbit - A critical evaluation of atomic oxygen testing with thermal atom systems

    NASA Technical Reports Server (NTRS)

    Koontz, S. L.; Albyn, K.; Leger, L.

    1990-01-01

    The use of thermal atom test methods as a materials selection and screening technique for low-earth orbit (LEO) spacecraft is critically evaluated. The chemistry and physics of thermal atom environments are compared with the LEO environment. The relative reactivities of a number of materials determined in thermal atom environments are compared with those observed in LEO and in high-quality LEO simulations. Reaction efficiencies (cu cm/atom) measured in a new type of thermal atom apparatus are one-thousandth to one ten-thousandth those observed in LEO, and many materials showing nearly identical reactivities in LEO show relative reactivities differing by as much as a factor of eight in thermal atom systems. A simple phenomenological kinetic model for the reaction of oxygen atoms with organic materials can be used to explain the differences in reactivity in different environments. Certain speciic thermal atom test environments can be used as reliable materials screening tools.

  12. Ly α Absorption at Transits of HD 209458b: A Comparative Study of Various Mechanisms Under Different Conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Khodachenko, M. L.; Lammer, H.; Kislyakova, K. G.

    To shed more light on the nature of the observed Ly α absorption during transits of HD 209458b and to quantify the major mechanisms responsible for the production of fast hydrogen atoms (the so-called energetic neutral atoms, ENAs) around the planet, 2D hydrodynamic multifluid modeling of the expanding planetary upper atmosphere, which is driven by stellar XUV, and its interaction with the stellar wind has been performed. The model self-consistently describes the escaping planetary wind, taking into account the generation of ENAs due to particle acceleration by the radiation pressure and by the charge exchange between the stellar wind protonsmore » and planetary atoms. The calculations in a wide range of stellar wind parameters and XUV flux values showed that under typical Sun-like star conditions, the amount of generated ENAs is too small, and the observed absorption at the level of 6%–8% can be attributed only to the non-resonant natural line broadening. For lower XUV fluxes, e.g., during the activity minima, the number of planetary atoms that survive photoionization and give rise to ENAs increases, resulting in up to 10%–15% absorption at the blue wing of the Ly α line, caused by resonant thermal line broadening. A similar asymmetric absorption can be seen under the conditions realized during coronal mass ejections, when sufficiently high stellar wind pressure confines the escaping planetary material within a kind of bowshock around the planet. It was found that the radiation pressure in all considered cases has a negligible contribution to the production of ENAs and the corresponding absorption.« less

  13. The Spectroscopy and Thermochemistry of Na and Na2.

    ERIC Educational Resources Information Center

    McSwiney, H. D.; And Others

    1989-01-01

    Presented is an experiment to show the connection between spectroscopy and thermochemistry by examining the spectra of atomic sodium and diatomic sodium. Background information; a description of the apparatus; procedures; calculations; and energy diagrams are included. (CW)

  14. METHOD AND APPARATUS FOR TESTING THE PRESENCE OF SPECIFIC ATOMIC ELEMENTS IN A SUBSTANCE

    DOEpatents

    Putman, J.L.

    1960-01-26

    Detection of specific atomic elements in a substance and particularly the applicability to well logging are discussed. The principal novelty resides in the determination of several of the auxiliary energy peaks in addition to the main energy peak of the gamma-ray energy spectrum of a substance and comparison of such peaks to the spectrum of the specific atomic element being tested for. thus resulting in identification of same. The invention facilitates the identification of specific elements even when in the presence of other elements having similar gamma energy spectra as to the main energy peaks.

  15. Trace determination of antimony by hydride generation atomic absorption spectrometry with analyte preconcentration/atomization in a dielectric barrier discharge atomizer.

    PubMed

    Zurynková, Pavla; Dědina, Jiří; Kratzer, Jan

    2018-06-20

    Atomization conditions for antimony hydride in the plasma atomizer based on a dielectric barrier discharge (DBD) with atomic absorption spectrometric detection were optimized. Argon was found as the best discharge gas under a flow rate of 50 mL min - 1 while the DBD power was optimum at 30 W. Analytical figures of merit including interference study of As, Se and Bi have been subsequently investigated and the results compared to those found in an externally heated quartz tube atomizer (QTA). The limit of detection (LOD) reached in DBD (0.15 ng mL -1  Sb) is comparable to that observed in QTA (0.14 ng mL -1  Sb). Finally, possibility of Sb preconcentration by stibane in situ trapping in a DBD atomizer was studied. For trapping time of 300 s, the preconcentration efficiency and LOD, respectively, were 103 ± 2% and 0.02 ng mL -1 . Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Measuring Two Key Parameters of H3 Color Centers in Diamond

    NASA Technical Reports Server (NTRS)

    Roberts, W. Thomas

    2005-01-01

    A method of measuring two key parameters of H3 color centers in diamond has been created as part of a continuing effort to develop tunable, continuous-wave, visible lasers that would utilize diamond as the lasing medium. (An H3 color center in a diamond crystal lattice comprises two nitrogen atoms substituted for two carbon atoms bonded to a third carbon atom. H3 color centers can be induced artificially; they also occur naturally. If present in sufficient density, they impart a yellow hue.) The method may also be applicable to the corresponding parameters of other candidate lasing media. One of the parameters is the number density of color centers, which is needed for designing an efficient laser. The other parameter is an optical-absorption cross section, which, as explained below, is needed for determining the number density. The present method represents an improvement over prior methods in which optical-absorption measurements have been used to determine absorption cross sections or number densities. Heretofore, in order to determine a number density from such measurements, it has been necessary to know the applicable absorption cross section; alternatively, to determine the absorption cross section from such measurements, it has been necessary to know the number density. If, as in this case, both the number density and the absorption cross section are initially unknown, then it is impossible to determine either parameter in the absence of additional information.

  17. Super-resolution atomic force photoactivated microscopy of biological samples (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Lee, Seunghyun; Kim, Hyemin; Shin, Seungjun; Doh, Junsang; Kim, Chulhong

    2017-03-01

    Optical microscopy (OM) and photoacoustic microscopy (PAM) have previously been used to image the optical absorption of intercellular features of biological cells. However, the optical diffraction limit ( 200 nm) makes it difficult for these modalities to image nanoscale inner cell structures and the distribution of internal cell components. Although super-resolution fluorescence microscopy, such as stimulated emission depletion microscopy (STED) and stochastic optical reconstruction microscopy (STORM), has successfully performed nanoscale biological imaging, these modalities require the use of exogenous fluorescence agents, which are unfavorable for biological samples. Our newly developed atomic force photoactivated microscopy (AFPM) can provide optical absorption images with nanoscale lateral resolution without any exogenous contrast agents. AFPM combines conventional atomic force microscopy (AFM) and an optical excitation system, and simultaneously provides multiple contrasts, such as the topography and magnitude of optical absorption. AFPM can detect the intrinsic optical absorption of samples with 8 nm lateral resolution, easily overcoming the diffraction limit. Using the label-free AFPM system, we have successfully imaged the optical absorption properties of a single melanoma cell (B16F10) and a rosette leaf epidermal cell of Arabidopsis (ecotype Columbia (Col-0)) with nanoscale lateral resolution. The remarkable images show the melanosome distribution of a melanoma cell and the biological structures of a plant cell. AFPM provides superior imaging of optical absorption with a nanoscale lateral resolution, and it promises to become widely used in biological and chemical research.

  18. Focusing Light Beams To Improve Atomic-Vapor Optical Buffers

    NASA Technical Reports Server (NTRS)

    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.

  19. Use of multiwavelength emission from hollow cathode lamp for measurement of state resolved atom density of metal vapor produced by electron beam evaporation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Majumder, A.; Dikshit, B.; Bhatia, M. S.

    2008-09-15

    State resolved atom population of metal vapor having low-lying metastable states departs from equilibrium value. It needs to be experimentally investigated. This paper reports the use of hollow cathode lamp based atomic absorption spectroscopy technique to measure online the state resolved atom density (ground and metastable) of metal vapor in an atomic beam produced by a high power electron gun. In particular, the advantage of availability of multiwavelength emission in hollow cathode lamp is used to determine the atom density in different states. Here, several transitions pertaining to a given state have also been invoked to obtain the mean valuemore » of atom density thereby providing an opportunity for in situ averaging. It is observed that at higher source temperatures the atoms from metastable state relax to the ground state. This is ascribed to competing processes of atom-atom and electron-atom collisions. The formation of collision induced virtual source is inferred from measurement of atom density distribution profile along the width of the atomic beam. The total line-of-sight average atom density measured by absorption technique using hollow cathode lamp is compared to that measured by atomic vapor deposition method. The presence of collisions is further supported by determination of beaming exponent by numerically fitting the data.« less

  20. Materials screening chamber for testing materials resistance to atomic oxygen

    NASA Technical Reports Server (NTRS)

    Pippin, H. G.; Carruth, Ralph

    1989-01-01

    A unique test chamber for exposing material to a known flux of oxygen atoms is described. The capabilities and operating parameters of the apparatus include production of an oxygen atom flux in excess of 5 x 10 to the 16th atoms/sq cm-sec, controlled heating of the sample specimen, RF circuitry to contain the plasma within a small volume, and long exposure times. Flux measurement capabilities include a calorimetric probe and a light titration system. Accuracy and limitations of these techniques are discussed. An extension to the main chamber to allow simultaneous ultraviolet and atomic oxygen exposure is discussed. The oxygen atoms produced are at thermal energies. Sample specimens are maintained at any selected temperature between ambient and 200 C, to within + or - 2 C. A representative example of measurements made using the chamber is presented.

  1. Characterization of micron-sized, optical coating defects by photothermal deflection microscopy

    NASA Astrophysics Data System (ADS)

    Abate, J. A.; Schmid, A. W.; Guardalben, M. G.; Smith, D. J.; Jacobs, S. D.

    1984-04-01

    Information about the localized absorbing defects in optical thin films is required for a better understanding of laser induced damage. Photothermal deflection microscopy offers a nondestructive optical diagnostic which yields spatially resolved absorption data on simple and multiple layer AR and HR dielectric coatings. The computer controlled apparatus used to generate absorption maps of dielectric thin films and an experiment in which a partial correlation between localized absorption sites and damage caused by nanosecond laser irradiation at 351 nm is established are described. An absolute calibration of absorption for our measurement technique is presented here. Micron sized absorbtive defects of Cu were introduced into our coatings to provide a means of calibration. Also presented here are some preliminary data on the modification of the absorption signatures measured by photothermal deflection as a function of the location of the defect within the coating layers.

  2. Method of and apparatus for measuring temperature and pressure. [atmospheric sounding

    NASA Technical Reports Server (NTRS)

    Korb, C. L.; Kalshoven, J. E., Jr. (Inventor)

    1985-01-01

    Laser beams are transmitted through gas to a reflecting target, which may be either a solid surface or particulate matter in gas or the gas molecules. The return beams are measured to determine the amount of energy absorbed by the gas. For temperature measurements, the laser beam has a wavelength at which the gas exhibits a relatively temperature sensitive and pressure insensitive absorption characteristic for pressure measurements, the laser beam has a wavelength at which the gas has a relatively pressure sensitive and temperature insensitive absorption characteristic. To reduce the effects of scattering on the absorption measurements a reference laser beam with a weak absorption characteristic is transmitted colinearly with the data beam having a strong absorption characteristic. The two signals are processed as a ratio to eliminate back scattering. Embodiments of transmitters and receivers described include a sequential laser pulse transmitter and receiver, a simultaneous laser pulse transmitter and receiver.

  3. Index of refraction engineering in five-level dressed interacting ground states atoms.

    PubMed

    Sagona-Stophel, Steven A; Weatherall, James Owen; Search, Christopher P

    2011-08-15

    We present a five-level atomic system in which the index of refraction of a probe laser can be enhanced or reduced below unity with vanishing absorption in the region between pairs of absorption and gain lines formed by dressing of the atoms with a control laser and rf/microwave fields. By weak incoherent pumping of the population into a single metastable state, one can create several narrow amplifying resonances. At frequencies between these gain lines and additional absorption lines, there exist regions of vanishing absorption but resonantly enhanced index of refraction. In Rb vapors with density N in units of cm(-3), we predict an index of refraction up to n≈√(1+1.2×10(-14)N) for the D1 line, which is more than an order of magnitude larger than other proposals for index of refraction enhancement. Furthermore, the index can be readily reduced below 1 by simply changing the sign of the probe or rf field detunings. This enhancement is robust with respect to homogeneous and inhomogeneous broadening. © 2011 Optical Society of America

  4. Formation of nanostructures in Eu3+ doped glass-ceramics: an XAS study.

    PubMed

    Pellicer-Porres, J; Segura, A; Martínez-Criado, G; Rodríguez-Mendoza, U R; Lavín, V

    2013-01-16

    We describe the results of x-ray absorption experiments carried out to deduce structural and chemical information in Eu(3+) doped, transparent, oxyfluoride glass and nanostructured glass-ceramic samples. The spectra were measured at the Pb and Eu-L(III) edges. The Eu environment in the glass samples is observed to be similar to that of EuF(3). Complementary x-ray diffraction experiments show that thermal annealing creates β-PbF(2) type nanocrystals. X-ray absorption indicates that Eu ions act as seeds in the nanocrystal formation. There is evidence of interstitial fluorine atoms around Eu ions as well as Eu dimers. X-ray absorption at the Pb-L(III) edge shows that after the thermal treatment most lead atoms form a PbO amorphous phase and that only 10% of the lead atoms remain available to form β-PbF(2) type nanocrystals. Both x-ray diffraction and absorption point to a high Eu content in the nanocrystals. Our study suggests new approaches to the oxyfluoride glass-ceramic synthesis in order to further improve their properties.

  5. Use of electrothermal atomic absorption spectrometry for size profiling of gold and silver nanoparticles.

    PubMed

    Panyabut, Teerawat; Sirirat, Natnicha; Siripinyanond, Atitaya

    2018-02-13

    Electrothermal atomic absorption spectrometry (ETAAS) was applied to investigate the atomization behaviors of gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) in order to relate with particle size information. At various atomization temperatures from 1400 °C to 2200 °C, the time-dependent atomic absorption peak profiles of AuNPs and AgNPs with varying sizes from 5 nm to 100 nm were examined. With increasing particle size, the maximum absorbance was observed at the longer time. The time at maximum absorbance was found to linearly increase with increasing particle size, suggesting that ETAAS can be applied to provide the size information of nanoparticles. With the atomization temperature of 1600 °C, the mixtures of nanoparticles containing two particle sizes, i.e., 5 nm tannic stabilized AuNPs with 60, 80, 100 nm citrate stabilized AuNPs, were investigated and bimodal peaks were observed. The particle size dependent atomization behaviors of nanoparticles show potential application of ETAAS for providing size information of nanoparticles. The calibration plot between the time at maximum absorbance and the particle size was applied to estimate the particle size of in-house synthesized AuNPs and AgNPs and the results obtained were in good agreement with those from flow field-flow fractionation (FlFFF) and transmission electron microscopy (TEM) techniques. Furthermore, the linear relationship between the activation energy and the particle size was observed. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Counterfactual Rydberg gate for photons

    NASA Astrophysics Data System (ADS)

    Garcia-Escartin, Juan Carlos; Chamorro-Posada, Pedro

    2012-03-01

    Quantum computation with photons requires efficient two-photon gates. We put forward a two-photon entangling gate which uses an intermediate atomic system. The system includes a single Rydberg atom which can switch on and off photon absorption in an ensemble using the dipole blockade. The gate is based in a counterfactual protocol. The mere possibility of an absorption that can only occur with a vanishing probability steers the photons to the desired final state.

  7. Measurements of uranium mass confined in high density plasmas

    NASA Technical Reports Server (NTRS)

    Stoeffler, R. C.

    1976-01-01

    An X-ray absorption method for measuring the amount of uranium confined in high density, rf-heated uranium plasmas is described. A comparison of measured absorption of 8 keV X-rays with absorption calculated using Beer Law indicated that the method could be used to measure uranium densities from 3 times 10 to the 16th power atoms/cu cm to 5 times 10 to the 18th power atoms/cu cm. Tests were conducted to measure the density of uranium in an rf-heated argon plasma with UF6 infection and with the power to maintain the discharge supplied by a 1.2 MW rf induction heater facility. The uranium density was measured as the flow rate through the test chamber was varied. A maximum uranium density of 3.85 times 10 to the 17th power atoms/cu cm was measured.

  8. Annealing induced atomic rearrangements on (Ga,In) (N,As) probed by hard X-ray photoelectron spectroscopy and X-ray absorption fine structure.

    PubMed

    Ishikawa, Fumitaro; Higashi, Kotaro; Fuyuno, Satoshi; Morifuji, Masato; Kondow, Masahiko; Trampert, Achim

    2018-04-13

    We study the effects of annealing on (Ga 0.64 ,In 0.36 ) (N 0.045 ,As 0.955 ) using hard X-ray photoelectron spectroscopy and X-ray absorption fine structure measurements. We observed surface oxidation and termination of the N-As bond defects caused by the annealing process. Specifically, we observed a characteristic chemical shift towards lower binding energies in the photoelectron spectra related to In. This phenomenon appears to be caused by the atomic arrangement, which produces increased In-N bond configurations within the matrix, as indicated by the X-ray absorption fine structure measurements. The reduction in the binding energies of group-III In, which occurs concomitantly with the atomic rearrangements of the matrix, causes the differences in the electronic properties of the system before and after annealing.

  9. Matrix effects on the determination of manganese in geological materials by atomic-absorption spectrophotometry under different flame conditions

    USGS Publications Warehouse

    Sanzolone, R.F.; Chao, T.T.

    1978-01-01

    Suppression caused by five of the seven matrix elements studied (Si, Al, Fe, Ca and Mg) was observed in the atomic-absorption determination of manganese in geological materials, when synthetic solutions and the recommended oxidizing air-acetylene flame were used. The magnitude of the suppression effects depends on (1) the kind and concentration of the interfering elements, (2) the type of acid medium, and (3) the concentration of manganese to be determined. All interferences noted are removed or alleviated by using a reducing nitrous oxide-acetylene flame. The atomic-absorption method using this flame can be applied to the determination of total and extractable manganese in a wide range of geological materials without interferences. Analyses of six U.S. Geological Survey rock standards for manganese gave results in agreement with the reported values. ?? 1978.

  10. A Comprehensive X-Ray Absorption Model for Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Gorczyca, T. W.; Bautista, M. A.; Hasoglu, M. F.; Garcia, J.; Gatuzz, E.; Kaastra, J. S.; Kallman, T. R.; Manson, S. T.; Mendoza, C.; Raassen, A. J. J.; hide

    2013-01-01

    An analytical formula is developed to accurately represent the photoabsorption cross section of atomic Oxygen for all energies of interest in X-ray spectral modeling. In the vicinity of the K edge, a Rydberg series expression is used to fit R-matrix results, including important orbital relaxation effects, that accurately predict the absorption oscillator strengths below threshold and merge consistently and continuously to the above-threshold cross section. Further, minor adjustments are made to the threshold energies in order to reliably align the atomic Rydberg resonances after consideration of both experimental and observed line positions. At energies far below or above the K-edge region, the formulation is based on both outer- and inner-shell direct photoionization, including significant shake-up and shake-off processes that result in photoionization-excitation and double-photoionization contributions to the total cross section. The ultimate purpose for developing a definitive model for oxygen absorption is to resolve standing discrepancies between the astronomically observed and laboratory-measured line positions, and between the inferred atomic and molecular oxygen abundances in the interstellar medium from XSTAR and SPEX spectral models.

  11. A Technology Demonstration Experiment for Laser Cooled Atomic Clocks in Space

    NASA Technical Reports Server (NTRS)

    Klipstein, W. M.; Kohel, J.; Seidel, D. J.; Thompson, R. J.; Maleki, L.; Gibble, K.

    2000-01-01

    We have been developing a laser-cooling apparatus for flight on the International Space Station (ISS), with the intention of demonstrating linewidths on the cesium clock transition narrower than can be realized on the ground. GLACE (the Glovebox Laser- cooled Atomic Clock Experiment) is scheduled for launch on Utilization Flight 3 (UF3) in 2002, and will be mounted in one of the ISS Glovebox platforms for an anticipated 2-3 week run. Separate flight definition projects funded at NIST and Yale by the Micro- gravity Research Division of NASA as a part of its Laser Cooling and Atomic Physics (LCAP) program will follow GLACE. Core technologies for these and other LCAP missions are being developed at JPL, with the current emphasis on developing components such as the laser and optics subsystem, and non-magnetic vacuum-compatible mechanical shutters. Significant technical challenges in developing a space qualifiable laser cooling apparatus include reducing the volume, mass, and power requirements, while increasing the ruggedness and reliability in order to both withstand typical launch conditions and achieve several months of unattended operation. This work was performed at the Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration.

  12. Modular injector integrated linear apparatus with motion profile optimization for spatial atomic layer deposition.

    PubMed

    Wang, Xiaolei; Li, Yun; Lin, Jilong; Shan, Bin; Chen, Rong

    2017-11-01

    A spatial atomic layer deposition apparatus integrated with a modular injector and a linear motor has been designed. It consists of four parts: a precursor delivery manifold, a modular injector, a reaction zone, and a driving unit. An injector with multi-layer structured channels is designed to help improve precursor distribution homogeneity. During the back and forth movement of the substrate at high speed, the inertial impact caused by jerk and sudden changes of acceleration will degrade the film deposition quality. Such residual vibration caused by inertial impact will aggravate the fluctuation of the gap distance between the injector and the substrate in the deposition process. Thus, an S-curve motion profile is implemented to reduce the large inertial impact, and the maximum position error could be reduced by 84%. The microstructure of the film under the S-curve motion profile shows smaller root-mean-square and scanning voltage amplitude under an atomic force microscope, which verifies the effectiveness of the S-curve motion profile in reducing the residual vibration and stabilizing the gap distance between the injector and the substrate. The film deposition rate could reach 100 nm/min while maintaining good uniformity without obvious periodic patterns on the surface.

  13. Modular injector integrated linear apparatus with motion profile optimization for spatial atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Wang, Xiaolei; Li, Yun; Lin, Jilong; Shan, Bin; Chen, Rong

    2017-11-01

    A spatial atomic layer deposition apparatus integrated with a modular injector and a linear motor has been designed. It consists of four parts: a precursor delivery manifold, a modular injector, a reaction zone, and a driving unit. An injector with multi-layer structured channels is designed to help improve precursor distribution homogeneity. During the back and forth movement of the substrate at high speed, the inertial impact caused by jerk and sudden changes of acceleration will degrade the film deposition quality. Such residual vibration caused by inertial impact will aggravate the fluctuation of the gap distance between the injector and the substrate in the deposition process. Thus, an S-curve motion profile is implemented to reduce the large inertial impact, and the maximum position error could be reduced by 84%. The microstructure of the film under the S-curve motion profile shows smaller root-mean-square and scanning voltage amplitude under an atomic force microscope, which verifies the effectiveness of the S-curve motion profile in reducing the residual vibration and stabilizing the gap distance between the injector and the substrate. The film deposition rate could reach 100 nm/min while maintaining good uniformity without obvious periodic patterns on the surface.

  14. A time-of-flight spectrometer for measuring inelastic to elastic differential cross-section ratios for electron-gas scattering

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    LeClair, L.R.; Trajmar, S.; Khakoo, M.A.

    1996-05-01

    We describe a crossed electron beam-atomic beam apparatus which utilizes a pulsed electron gun and field free drift tube to obtain time-of-flight (TOF) spectra of electrons scattered from atoms and molecules. This apparatus was constructed for the purpose of obtaining inelastic-to-elastic differential cross-section (DCS) ratios in the energy range extending from threshold to several eV above the threshold of the inelastic channel. The TOF approach eliminates the need for complicated calibration procedures required when using conventional electrostatic electron energy-loss spectroscopy (EELS) at these low energies. The characteristics of the apparatus will be given, along with representative TOF spectra from carbonmore » monoxide. From those spectra we obtained DCS ratios at 90{degree} scattering angle for excitation of the {ital a}{sup 3}{Pi} state of CO, in the impact energy range of 6{endash}15 eV. These ratios were measured with uncertainties as small as {plus_minus}4{percent}, which represents a substantial improvement over previous measurements in this energy range. This demonstrates the feasibility of using the TOF technique to measure DCS ratios which in turn can serve as secondary standards to normalize other inelastic DCSs obtained from measurements with EELS. {copyright} {ital 1996 American Institute of Physics.}« less

  15. Method of and apparatus for measuring vapor density

    DOEpatents

    Nelson, L.D.; Cerni, T.A.

    1989-10-17

    Apparatus and method are disclosed which determine the concentration of an individual component, such as water vapor, of a multi-component mixture, such as a gaseous mixture for cooling a nuclear reactor. A hygrometer apparatus includes an infrared source for producing a broadband infrared energy beam that includes a strong water vapor absorption band and a weak water vapor absorption region. The beam is chopped to select infrared pulses. A temporally first pulse has a wavelength in the weakly absorbing region, a temporally second pulse has a wavelength in the strong band and a temporally third pulse has a wavelength in the weakly absorbing region. A fourth reference pulse representing background radiation is interposed in such chopped pulses. An indium arsenide infrared sensor is responsive to the pulses for generating an output signal in proportion to an equation given in the patent where N1 is proportional to the transmission through the sample of the first signal, N4 is related to the background radiation, and [K2 (N2-N4) + K3 (N3-N4)] is the time-weighted average of the transmission through the sample of the second and third pulses applicable at the time of the second pulse, with the reference pulse N4 being subtracted in each case to render the ratio independent of variations in the background radiation. 11 figs.

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  17. Electronic theoretical study of the influences of O adsorption on the electronic structure and optical properties of graphene

    NASA Astrophysics Data System (ADS)

    Shuang, Zhou; Guili, Liu; Dazhi, Fan

    2017-02-01

    The electronic structure and optical properties of adsorbing O atoms on graphene with different O coverage are researched using the density functional theory based upon the first-principle study to obtain further insight into properties of graphene. The adsorption energies, band structures, the density of states, light absorption coefficient and reflectivity of each system are calculated theoretically after optimizing structures of each system with different O coverage. Our calculations show that adsorption of O atoms on graphene increases the bond length of C-C which adjacent to the O atoms. When the O coverage is 9.4%, the adsorption energy (3.91 eV) is the maximum, which only increases about 1.6% higher than that of 3.1% O coverage. We find that adsorbed O atoms on pristine graphene opens up indirect gap of about 0.493-0.952 eV. Adsorbing O atoms make pristine graphene from metal into a semiconductor. When the O coverage is 9.4%, the band gap (0.952 eV) is the maximum. Comparing with pristine graphene, we find the density of states at Fermi level of O atoms adsorbing on graphene with different coverage are significantly increased. We also find that light absorption coefficient and reflectivity peaks are significantly reduced, and the larger the coverage, the smaller the absorption coefficient and reflectivity peaks are. And the blue shift phenomenon appears.

  18. Preferred site occupation of 3 d atoms in NixF e4 -xN (x =1 and 3) films revealed by x-ray absorption spectroscopy and magnetic circular dichroism

    NASA Astrophysics Data System (ADS)

    Takata, Fumiya; Ito, Keita; Takeda, Yukiharu; Saitoh, Yuji; Takanashi, Koki; Kimura, Akio; Suemasu, Takashi

    2018-02-01

    X-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism measurements were performed at the Ni and Fe L2 ,3 absorption edges for N ixF e4 -xN (x =1 and 3) epitaxial films. Spectral line-shape analysis and element-specific magnetic moment evaluations are presented. Shoulders at approximately 2 eV above the Ni L2 ,3 main peaks in the XAS spectrum of N i3FeN were interpreted to originate from hybridization of orbitals between Ni 3 d at face-centered (II) sites and N 2 p at body-centered sites, while such features were missing in NiF e3N film. Similar shoulders were observed at Fe L2 ,3 edges in both films. These results indicate that the orbitals of Ni atoms did not hybridize with those of N atoms in the NiF e3N film. Hence, Ni atoms preferentially occupied corner (I) sites, where the hybridization was weak because of the relatively long distance between Ni at I sites and N atoms. The relatively large magnetic moment deduced from sum-rule analysis of NiF e3N also showed a good agreement with the presence of Ni atoms at I sites.

  19. Atom beams split by gentle persuasion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pool, R.

    1994-02-25

    Two different research teams have taken a big step toward atom interferometry. They have succeeded in splitting atomic beams by using atoms in spin states that neither absorb nor reemit laser light. By proper adjustment of experimental conditions, atoms are changed from one spin state to another, without passing through the intermediary excited state. The atoms in essence absorb momentum from the laser photons, without absorption or emission of photons. The change in momentum deflects atoms in the proper spin state.

  20. An atom interferometer inside a hollow-core photonic crystal fiber

    PubMed Central

    Xin, Mingjie; Leong, Wui Seng; Chen, Zilong; Lan, Shau-Yu

    2018-01-01

    Coherent interactions between electromagnetic and matter waves lie at the heart of quantum science and technology. However, the diffraction nature of light has limited the scalability of many atom-light–based quantum systems. We use the optical fields in a hollow-core photonic crystal fiber to spatially split, reflect, and recombine a coherent superposition state of free-falling 85Rb atoms to realize an inertia-sensitive atom interferometer. The interferometer operates over a diffraction-free distance, and the contrasts and phase shifts at different distances agree within one standard error. The integration of phase coherent photonic and quantum systems here shows great promise to advance the capability of atom interferometers in the field of precision measurement and quantum sensing with miniature design of apparatus and high efficiency of laser power consumption. PMID:29372180

  1. Characterization of local atomic structure in Co/Zn based ZIFs by XAFS

    NASA Astrophysics Data System (ADS)

    Podkovyrina, Yulia; Butova, Vera; Bulanova, Elena; Budnyk, Andriy; Kremennaya, Maria; Soldatov, Alexander; Lamberti, Carlo

    2018-03-01

    The local atomic structure in bimetallic Co/Zn zeolitic imidazolate frameworks (ZIFs) was studied using X-ray Absorption Fine Structure (XAFS) spectroscopy and theoretical calculations. The experimental Co K-edge and Zn K-edge XANES (X-ray Absorption Near Edge Structure) spectra of Zn1-xCoxC8H10N4 samples (x = 0.05, 0.25, 0.75) synthesized by microwave synthesis were compared with the data for the ZIF-67 (x=1) and ZIF-8 (x=0). Theoretical XANES spectra for the bimetallic ZIFs were calculated. It was shown that in bimetallic ZIFs the Co and Zn atoms have the similar local environment.

  2. A stable frequency comb directly referenced to rubidium electromagnetically induced transparency and two-photon transitions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hou, Dong; Wu, Jiutao; Zhang, Shuangyou

    2014-03-17

    We demonstrate an approach to create a stable erbium-fiber-based frequency comb at communication band by directly locking the combs to two rubidium atomic transitions resonances (electromagnetically induced transparency absorption and two-photon absorption), respectively. This approach directly transfers the precision and stability of the atomic transitions to the comb. With its distinguishing feature of compactness by removing the conventional octave-spanning spectrum and f-to-2f beating facilities and the ability to directly control the comb's frequency at the atomic transition frequency, this stable optical comb can be widely used in optical communication, frequency standard, and optical spectroscopy and microscopy.

  3. Bond-length relaxation in crystalline Si1-xGex alloys: An extended x-ray-absorption fine-structure study

    NASA Astrophysics Data System (ADS)

    Kajiyama, Hiroshi; Muramatsu, Shin-Ichi; Shimada, Toshikazu; Nishino, Yoichi

    1992-06-01

    Extended x-ray-absorption fine-structure spectra for crystalline Si1-xGex alloys, measured at the K edge of Ge at room temperature, are analyzed with a curve-fitting method based on the spherical-wave approximation. The Ge-Ge and Ge-Si bond lengths, coordination numbers of Ge and Si atoms around a Ge atom, and Debye-Waller factors of Ge and Si atoms are obtained. It is shown that Ge-Ge and Ge-Si bonds relax completely, for all Ge concentrations of their study, while the lattice constant varies monotonically, following Vegard's law. As noted by Bragg and later by Pauling and Huggins, the Ge-Ge and Ge-Si bond lengths are close to the sum of their constituent-element atomic radii: nearly 2.45 Å for Ge-Ge bonds and 2.40 Å for Ge-Si bonds. A study on the coordination around a Ge atom in the alloys revealed that Ge and Si atoms mix randomly throughout the compositional range studied.

  4. Validation of an analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals in soil

    PubMed Central

    2013-01-01

    Background The aim of this paper was the validation of a new analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals (Ag, Cd, Co, Cr, Cu, Ni, Pb and Zn) in soil after microwave assisted digestion in aqua regia. Determinations were performed on the ContrAA 300 (Analytik Jena) air-acetylene flame spectrometer equipped with xenon short-arc lamp as a continuum radiation source for all elements, double monochromator consisting of a prism pre-monocromator and an echelle grating monochromator, and charge coupled device as detector. For validation a method-performance study was conducted involving the establishment of the analytical performance of the new method (limits of detection and quantification, precision and accuracy). Moreover, the Bland and Altman statistical method was used in analyzing the agreement between the proposed assay and inductively coupled plasma optical emission spectrometry as standardized method for the multielemental determination in soil. Results The limits of detection in soil sample (3σ criterion) in the high-resolution continuum source flame atomic absorption spectrometry method were (mg/kg): 0.18 (Ag), 0.14 (Cd), 0.36 (Co), 0.25 (Cr), 0.09 (Cu), 1.0 (Ni), 1.4 (Pb) and 0.18 (Zn), close to those in inductively coupled plasma optical emission spectrometry: 0.12 (Ag), 0.05 (Cd), 0.15 (Co), 1.4 (Cr), 0.15 (Cu), 2.5 (Ni), 2.5 (Pb) and 0.04 (Zn). Accuracy was checked by analyzing 4 certified reference materials and a good agreement for 95% confidence interval was found in both methods, with recoveries in the range of 94–106% in atomic absorption and 97–103% in optical emission. Repeatability found by analyzing real soil samples was in the range 1.6–5.2% in atomic absorption, similar with that of 1.9–6.1% in optical emission spectrometry. The Bland and Altman method showed no statistical significant difference between the two spectrometric methods for 95% confidence interval. Conclusions High-resolution continuum source flame atomic absorption spectrometry can be successfully used for the rapid, multielemental determination of hazardous/priority hazardous metals in soil with similar analytical performances to those in inductively coupled plasma optical emission spectrometry. PMID:23452327

  5. Validation of an analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals in soil.

    PubMed

    Frentiu, Tiberiu; Ponta, Michaela; Hategan, Raluca

    2013-03-01

    The aim of this paper was the validation of a new analytical method based on the high-resolution continuum source flame atomic absorption spectrometry for the fast-sequential determination of several hazardous/priority hazardous metals (Ag, Cd, Co, Cr, Cu, Ni, Pb and Zn) in soil after microwave assisted digestion in aqua regia. Determinations were performed on the ContrAA 300 (Analytik Jena) air-acetylene flame spectrometer equipped with xenon short-arc lamp as a continuum radiation source for all elements, double monochromator consisting of a prism pre-monocromator and an echelle grating monochromator, and charge coupled device as detector. For validation a method-performance study was conducted involving the establishment of the analytical performance of the new method (limits of detection and quantification, precision and accuracy). Moreover, the Bland and Altman statistical method was used in analyzing the agreement between the proposed assay and inductively coupled plasma optical emission spectrometry as standardized method for the multielemental determination in soil. The limits of detection in soil sample (3σ criterion) in the high-resolution continuum source flame atomic absorption spectrometry method were (mg/kg): 0.18 (Ag), 0.14 (Cd), 0.36 (Co), 0.25 (Cr), 0.09 (Cu), 1.0 (Ni), 1.4 (Pb) and 0.18 (Zn), close to those in inductively coupled plasma optical emission spectrometry: 0.12 (Ag), 0.05 (Cd), 0.15 (Co), 1.4 (Cr), 0.15 (Cu), 2.5 (Ni), 2.5 (Pb) and 0.04 (Zn). Accuracy was checked by analyzing 4 certified reference materials and a good agreement for 95% confidence interval was found in both methods, with recoveries in the range of 94-106% in atomic absorption and 97-103% in optical emission. Repeatability found by analyzing real soil samples was in the range 1.6-5.2% in atomic absorption, similar with that of 1.9-6.1% in optical emission spectrometry. The Bland and Altman method showed no statistical significant difference between the two spectrometric methods for 95% confidence interval. High-resolution continuum source flame atomic absorption spectrometry can be successfully used for the rapid, multielemental determination of hazardous/priority hazardous metals in soil with similar analytical performances to those in inductively coupled plasma optical emission spectrometry.

  6. Fluid Properties Measurements Using Wavelength Modulation Spectroscopy with First Harmonic Detection

    NASA Technical Reports Server (NTRS)

    Silver, Joel A. (Inventor); Chen, Shin-Juh (Inventor)

    2014-01-01

    An apparatus and method for monitoring gas velocity, temperature, and pressure in combustion systems and flow devices, in particular at inlets and isolators of scramjet engines. The invention employs wavelength modulation spectroscopy with first harmonic detection and without the need to scan the full absorption spectra.

  7. The Beer Lambert Law Measurement Made Easy

    ERIC Educational Resources Information Center

    Onorato, Pasquale; Gratton, Luigi M.; Polesell, Marta; Salmoiraghi, Alessandro; Oss, Stefano

    2018-01-01

    We propose the use of a smartphone based apparatus as a valuable tool for investigating the optical absorption of a material and to verify the exponential decay predicted by Beer's law. The very simple experimental activities presented here, suitable for undergraduate students, allows one to measure the material transmittance including its…

  8. The Pharmacokinetics of Atomized Lidocaine Administered via the Trachea: A Randomized Trial.

    PubMed

    Takaenoki, Yumiko; Masui, Kenichi; Oda, Yutaka; Kazama, Tomiei

    2016-07-01

    Under emergent conditions, endotracheal drug administration may be an effective method of delivering emergency drugs. A common technique is to administer these drugs using a nonatomized spray. Atomized drug delivery may be an attractive alternative to nonatomized delivery because atomized particles are small, cover a large surface area, and may better adhere to endotracheal membrane resulting in more effective drug absorption. In this study, we compared the pharmacokinetic profile of lidocaine administered into the trachea using an atomized or a nonatomized technique. Twenty patients were anesthetized using propofol and remifentanil. Ten minutes after rocuronium was administered, patients received 4% lidocaine (2 mg/kg) intratracheally over 2 seconds before tracheal intubation. Ten patients received atomized lidocaine using a mucosal atomization device, and the other 10 patients received nonatomized lidocaine using a traditional spray tube. Arterial lidocaine plasma concentrations were measured before; at 1, 3, 5, 7, 10, 15, 20, 30, 45, and 60 minutes; and then every 60 minutes after the administration of lidocaine until the end of the operation. We developed a pharmacokinetic model to examine whether bioavailability or absorption rate was different between atomized versus nonatomized lidocaine administration. The total body clearance was fixed at a published value to determine the bioavailability. Peak plasma concentrations were larger using the mucosal atomization device (median [range]: 1.9 [1.4-3.2] μg/mL) than the spray tube (1.1 [0.6-2.0] μg/mL; P = 0.0021). Our pharmacokinetic model estimated a difference of bioavailability between the atomized and the nonatomized lidocaine (0.801 and 0.559 respectively, P = 0.0005), whereas our model estimated no difference in the absorption rate constant (0.00688/min). Our results suggest that when using atomized delivery of lidocaine, less drug is required to achieve a near equivalent plasma lidocaine concentration. Atomized drug administration may be a more efficient method for endotracheal drug administration.

  9. [Measurement of atomic number of alkali vapor and pressure of buffer gas based on atomic absorption].

    PubMed

    Zheng, Hui-jie; Quan, Wei; Liu, Xiang; Chen, Yao; Lu, Ji-xi

    2015-02-01

    High sensitivitymagnetic measurementscanbe achieved by utilizing atomic spinmanipulation in the spin-exchange-relaxation-free (SERF) regime, which uses an alkali cell as a sensing element. The atomic number density of the alkali vapor and the pressure of the buffer gasare among the most important parameters of the cell andrequire accurate measurement. A method has been proposed and developedto measure the atomic number density and the pressure based on absorption spectroscopy, by sweeping the absorption line and fittingthe experiment data with a Lorentzian profile to obtainboth parameters. Due to Doppler broadening and pressure broadening, which is mainly dominated by the temperature of the cell and the pressure of buffer gas respectively, this work demonstrates a simulation of the errorbetween the peaks of the Lorentzian profile and the Voigt profile caused by bothfactors. The results indicates that the Doppler broadening contribution is insignificant with an error less than 0.015% at 313-513 K for a 4He density of 2 amg, and an error of 0.1% in the presence of 0.6-5 amg at 393 K. We conclude that the Doppler broadening could be ignored under above conditions, and that the Lorentzianprofile is suitably applied to fit the absorption spectrumobtainingboth parameters simultaneously. In addition we discuss the resolution and the instability due to thelight source, wavelength and the temperature of the cell. We find that the cell temperature, whose uncertainty is two orders of magnitude larger than the instability of the light source and the wavelength, is one of the main factors which contributes to the error.

  10. Design strategies to minimize the radiative efficiency of global warming molecules

    PubMed Central

    Bera, Partha P.; Francisco, Joseph S.; Lee, Timothy J.

    2010-01-01

    A strategy is devised to screen molecules based on their radiative efficiency. The methodology should be useful as one additional constraint when determining the best molecule to use for an industrial application. The strategy is based on the results of a recent study where we examined molecular properties of global warming molecules using ab initio electronic structure methods to determine which fundamental molecular properties are important in assessing the radiative efficiency of a molecule. Six classes of perfluorinated compounds are investigated. For similar numbers of fluorine atoms, their absorption of radiation in the IR window decreases according to perfluoroethers > perfluorothioethers ≈ sulfur/carbon compounds > perfluorocarbons > perfluoroolefins > carbon/nitrogen compounds. Perfluoroethers and hydrofluorethers are shown to possess a large absorption in the IR window due to (i) the C─O bonds are very polar, (ii) the C-O stretches fall within the IR window and have large IR intensity due to their polarity, and (iii) the IR intensity for C-F stretches in which the fluorine atom is bonded to the carbon that is bonded to the oxygen atom is enhanced due to a larger C─F bond polarity. Lengthening the carbon chain leads to a larger overall absorption in the IR window, though the IR intensity per bond is smaller. Finally, for a class of partially fluorinated compounds with a set number of electronegative atoms, the overall absorption in the IR window can vary significantly, as much as a factor of 2, depending on how the fluorine atoms are distributed within the molecule. PMID:20439762

  11. Near-edge X-ray absorption spectra for metallic Cu and Mn

    NASA Astrophysics Data System (ADS)

    Greaves, G. N.; Durham, P. J.; Diakun, G.; Quinn, P.

    1981-11-01

    The measurement of X-ray absorption fine structure of metals- both in the extended region (EXAFS) as well as in the near edge region (XANES)-has been widely discussed (see refs 1-6 for Cu and refs 7-9 for Mn). The recent availability of intense X-ray fluxes from storage rings has usually been exploited for EXAFS leaving the XANES often with poorer resolution than earlier work performed on conventional sources (for example, compare the near edge structure for copper in ref. 1 with refs 3 or 6). In addition, whilst the theory and analysis of EXAFS is relatively well-established2,10, a theory for the strong scattering regime near to the absorption edge has only recently been developed11. We report here the first high resolution XANES spectra for Cu and Mn which were performed at the SRS storage ring at Daresbury. Although both metals have close-packed structures consisting of atoms of similar size their local atomic structure is different in detail. Significant differences are found in their respective XANES reflecting the senstivity of this region of the X-ray absorption fine structure to the local atomic structure. Spectra for the two metals have been analysed using the new multiple scattering formalism. This is a real space calculation and unlike a conventional band structure approach it does not require structural periodicity but works from the local arrangement of atoms.

  12. Wide-band 'black silicon' with atomic layer deposited NbN.

    PubMed

    Isakov, Kirill; Perros, Alexander Pyymaki; Shah, Ali; Lipsanen, Harri

    2018-08-17

    Antireflection surfaces are often utilized in optical components to reduce undesired reflection and increase absorption. We report on black silicon (b-Si) with dramatically enhanced absorption over a broad wavelength range (250-2500 nm) achieved by applying a 10-15 nm conformal coating of NbN with atomic layer deposition (ALD). The improvement is especially pronounced in the near infrared (NIR) range of 1100-2500 nm where absorption is increased by >90%. A significant increase of absorption is also observed over the ultraviolet range of 200-400 nm. Preceding NbN deposition with a nanostructured ALD Al 2 O 3 (n-Al 2 O 3 ) coating to enhance the NbN texture was also examined. Such texturing further improves absorption in the NIR, especially at longer wavelengths, strong absorption up to 4-5 μm wavelengths has been attested. For comparison, double side polished silicon and sapphire coated with 10 nm thick NbN exhibited absorption of only ∼55% in the NIR range of 1100-2500 nm. The results suggest a positive correlation between the surface area of NbN coating and optical absorption. Based on the wide-band absorption, the presented NbN-coated b-Si may be an attractive candidate for use in e.g. spectroscopic systems, infrared microbolometers.

  13. Laser absorption phenomena in flowing gas devices

    NASA Technical Reports Server (NTRS)

    Chapman, P. K.; Otis, J. H.

    1976-01-01

    A theoretical and experimental investigation is presented of inverse Bremsstrahlung absorption of CW CO2 laser radiation in flowing gases seeded with alkali metals. In order to motivate this development, some simple models are described of several space missions which could use laser powered rocket vehicles. Design considerations are given for a test call to be used with a welding laser, using a diamond window for admission of laser radiation at power levels in excess of 10 kW. A detailed analysis of absorption conditions in the test cell is included. The experimental apparatus and test setup are described and the results of experiments presented. Injection of alkali seedant and steady state absorption of the laser radiation were successfully demonstrated, but problems with the durability of the diamond windows at higher powers prevented operation of the test cell as an effective laser powered thruster.

  14. Apparatus and method for quantitative assay of samples of transuranic waste contained in barrels in the presence of matrix material

    DOEpatents

    Caldwell, J.T.; Herrera, G.C.; Hastings, R.D.; Shunk, E.R.; Kunz, W.E.

    1987-08-28

    Apparatus and method for performing corrections for matrix material effects on the neutron measurements generated from analysis of transuranic waste drums using the differential-dieaway technique. By measuring the absorption index and the moderator index for a particular drum, correction factors can be determined for the effects of matrix materials on the ''observed'' quantity of fissile and fertile material present therein in order to determine the actual assays thereof. A barrel flux monitor is introduced into the measurement chamber to accomplish these measurements as a new contribution to the differential-dieaway technology. 9 figs.

  15. Characteristics of the transmission loss apparatus at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Grosveld, F. W.

    1983-01-01

    A description of the Transmission Loss Apparatus at NASA Langley Research Center, which is specifically designed to accommodate general aviation type aircraft structures, is presented. The measurement methodology, referred to as the Plate Reference Method, is discussed and compared with the classical method as described in the Standard of the American Society for Testing and Materials. This measurement procedure enables reliable and accurate noise transmission loss measurements down to the 50 Hz one-third octave band. The transmission loss characteristics of add-on acoustical treatments, applied to the basic structure, can be established by inclusion of appropriate absorption corrections for the treatment.

  16. Laser controlled atom source for optical clocks.

    PubMed

    Kock, Ole; He, Wei; Świerad, Dariusz; Smith, Lyndsie; Hughes, Joshua; Bongs, Kai; Singh, Yeshpal

    2016-11-18

    Precision timekeeping has been a driving force in innovation, from defining agricultural seasons to atomic clocks enabling satellite navigation, broadband communication and high-speed trading. We are on the verge of a revolution in atomic timekeeping, where optical clocks promise an over thousand-fold improvement in stability and accuracy. However, complex setups and sensitivity to thermal radiation pose limitations to progress. Here we report on an atom source for a strontium optical lattice clock which circumvents these limitations. We demonstrate fast (sub 100 ms), cold and controlled emission of strontium atomic vapours from bulk strontium oxide irradiated by a simple low power diode laser. Our results demonstrate that millions of strontium atoms from the vapour can be captured in a magneto-optical trap (MOT). Our method enables over an order of magnitude reduction in scale of the apparatus. Future applications range from satellite clocks testing general relativity to portable clocks for inertial navigation systems and relativistic geodesy.

  17. Laser controlled atom source for optical clocks

    PubMed Central

    Kock, Ole; He, Wei; Świerad, Dariusz; Smith, Lyndsie; Hughes, Joshua; Bongs, Kai; Singh, Yeshpal

    2016-01-01

    Precision timekeeping has been a driving force in innovation, from defining agricultural seasons to atomic clocks enabling satellite navigation, broadband communication and high-speed trading. We are on the verge of a revolution in atomic timekeeping, where optical clocks promise an over thousand-fold improvement in stability and accuracy. However, complex setups and sensitivity to thermal radiation pose limitations to progress. Here we report on an atom source for a strontium optical lattice clock which circumvents these limitations. We demonstrate fast (sub 100 ms), cold and controlled emission of strontium atomic vapours from bulk strontium oxide irradiated by a simple low power diode laser. Our results demonstrate that millions of strontium atoms from the vapour can be captured in a magneto-optical trap (MOT). Our method enables over an order of magnitude reduction in scale of the apparatus. Future applications range from satellite clocks testing general relativity to portable clocks for inertial navigation systems and relativistic geodesy. PMID:27857214

  18. Building one molecule from a reservoir of two atoms

    NASA Astrophysics Data System (ADS)

    Liu, L. R.; Hood, J. D.; Yu, Y.; Zhang, J. T.; Hutzler, N. R.; Rosenband, T.; Ni, K.-K.

    2018-05-01

    Chemical reactions typically proceed via stochastic encounters between reactants. Going beyond this paradigm, we combined exactly two atoms in a single, controlled reaction. The experimental apparatus traps two individual laser-cooled atoms [one sodium (Na) and one cesium (Cs)] in separate optical tweezers and then merges them into one optical dipole trap. Subsequently, photoassociation forms an excited-state NaCs molecule. The discovery of previously unseen resonances near the molecular dissociation threshold and measurement of collision rates are enabled by the tightly trapped ultracold sample of atoms. As laser-cooling and trapping capabilities are extended to more elements, the technique will enable the study of more diverse, and eventually more complex, molecules in an isolated environment, as well as synthesis of designer molecules for qubits.

  19. A new apparatus for studies of quantized vortex dynamics in dilute-gas Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Newman, Zachary L.

    The presence of quantized vortices and a high level of control over trap geometries and other system parameters make dilute-gas Bose-Einstein condensates (BECs) a natural environment for studies of vortex dynamics and quantum turbulence in superfluids, primary interests of the BEC group at the University of Arizona. Such research may lead to deeper understanding of the nature of quantum fluid dynamics and far-from-equilbrium phenomena. Despite the importance of quantized vortex dynamics in the fields of superfluidity, superconductivity and quantum turbulence, direct imaging of vortices in trapped BECs remains a significant technical challenge. This is primarily due to the small size of the vortex core in a trapped gas, which is typically a few hundred nanometers in diameter. In this dissertation I present the design and construction of a new 87Rb BEC apparatus with the goal of studying vortex dynamics in trapped BECs. The heart of the apparatus is a compact vacuum chamber with a custom, all-glass science cell designed to accommodate the use of commercial high-numerical-aperture microscope objectives for in situ imaging of vortices. The designs for the new system are, in part, based on prior work in our group on in situ imaging of vortices. Here I review aspects of our prior work and discuss some of the successes and limitations that are relevant to the new apparatus. The bulk of the thesis is used to described the major subsystems of the new apparatus which include the vacuum chamber, the laser systems, the magnetic transfer system and the final magnetic trap for the atoms. Finally, I demonstrate the creation of a BEC of ˜ 2 x 106 87Rb atoms in our new system and show that the BEC can be transferred into a weak, spherical, magnetic trap with a well defined magnetic field axis that may be useful for future vortex imaging studies.

  20. Absorption spectroscopy of heavy alkaline earth metals Ba and Sr in rare gas matrices—CCSD(T) calculations and atomic site occupancies

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Davis, Barry M.; McCaffrey, John G., E-mail: john.mccaffrey@nuim.ie

    2016-01-28

    Isolation of the heavier alkaline earth metals Ba and Sr in the solid rare gases (RGs) Ar, Kr, and Xe is analysed with absorption spectroscopy and interpreted partly with the assistance of ab initio calculations of the diatomic M ⋅ RG ground state interaction potentials. The y{sup 1}P←a{sup 1}S resonance transitions in the visible spectral region are used to compare the isolation conditions of these two metal atom systems and calcium. Complex absorption bands were recorded in all three metal atom systems even after extensive sample annealing. Coupled cluster calculations conducted on the ground states of the nine M ⋅more » RG diatomics (M = Ca, Sr, and Ba; RG = Ar, Kr, and Xe) at the coupled cluster single, double, and non-iterative triple level of theory revealed long bond lengths (>5 Å) and shallow bound regions (<130 cm{sup −1}). All of the M ⋅ RG diatomics have bond lengths considerably longer than those of the rare gas dimers, with the consequence that isolation of these metal atoms in a single substitutional site of the solid rare gas is unlikely, with the possible exception of Ca/Xe. The luminescence of metal dimer bands has been recorded for Ba and Sr revealing very different behaviours. Resonance fluorescence with a lifetime of 15 ns is observed for the lowest energy transition of Sr{sub 2} while this transition is quenched in Ba{sub 2}. This behaviour is consistent with the absence of vibrational structure on the dimer absorption band in Ba{sub 2} indicating lifetime broadening arising from efficient relaxation to low-lying molecular states. More extensive 2D excitation-emission data recorded for the complex site structures present on the absorption bands of the atomic Ba and Sr systems will be presented in future publications.« less

  1. A variable-temperature nanostencil compatible with a low-temperature scanning tunneling microscope/atomic force microscope

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Steurer, Wolfram, E-mail: wst@zurich.ibm.com; Gross, Leo; Schlittler, Reto R.

    2014-02-15

    We describe a nanostencil lithography tool capable of operating at variable temperatures down to 30 K. The setup is compatible with a combined low-temperature scanning tunneling microscope/atomic force microscope located within the same ultra-high-vacuum apparatus. The lateral movement capability of the mask allows the patterning of complex structures. To demonstrate operational functionality of the tool and estimate temperature drift and blurring, we fabricated LiF and NaCl nanostructures on Cu(111) at 77 K.

  2. A variable-temperature nanostencil compatible with a low-temperature scanning tunneling microscope/atomic force microscope.

    PubMed

    Steurer, Wolfram; Gross, Leo; Schlittler, Reto R; Meyer, Gerhard

    2014-02-01

    We describe a nanostencil lithography tool capable of operating at variable temperatures down to 30 K. The setup is compatible with a combined low-temperature scanning tunneling microscope/atomic force microscope located within the same ultra-high-vacuum apparatus. The lateral movement capability of the mask allows the patterning of complex structures. To demonstrate operational functionality of the tool and estimate temperature drift and blurring, we fabricated LiF and NaCl nanostructures on Cu(111) at 77 K.

  3. Compact hydrogenator

    NASA Technical Reports Server (NTRS)

    Simmonds, P. G. (Inventor)

    1974-01-01

    The development and characteristics of a hydrogenating apparatus are described. The device consists of a reaction chamber which is selectively permeable to atomic hydrogen and catalytically active to a hydrogenating reaction. In one device, hydrogen is pumped out of the reaction chamber while the reactant remains inside to remove molecular hydrogen so that more atomic hydrogen can pass through the walls. In another device, the reactant is pumped through the reaction chamber, and the hydrogen is removed from the material leaving the chamber. The reactant is then cycled through the chamber.

  4. Continuous wave cavity ring-down spectroscopy for velocity distribution measurements in plasma.

    PubMed

    McCarren, D; Scime, E

    2015-10-01

    We report the development of a continuous wave cavity ring-down spectroscopic (CW-CRDS) diagnostic for real-time, in situ measurement of velocity distribution functions of ions and neutral atoms in plasma. This apparatus is less complex than conventional CW-CRDS systems. We provide a detailed description of the CW-CRDS apparatus as well as measurements of argon ions and neutrals in a high-density (10(9) cm(-3) < plasma density <10(13) cm(-3)) plasma. The CW-CRDS measurements are validated through comparison with laser induced fluorescence measurements of the same absorbing states of the ions and neutrals.

  5. Apparatus and method for measuring electrostatic polarization

    DOEpatents

    Hahn, Erwin L.; Clarke, John; Sloater, Tycho; Hilbert, Claude; Heaney, Michael B.

    1989-01-01

    An apparatus and method for measuring the electric properties of solid matter which provides data for determining the polarizability of the electron distributions contained therein is disclosed. A sample of the solid to be studied is placed between the plates of a capacitor where it acts as a dielectric. The sample is excited by the interaction of electromagnetic radiation with an atomic species contained in the sample. The voltage induced across the capacitor is then measured as a function of time with the aid of a high Q circuit tuned to a frequency related to the frequency of the applied electromagnetic energy.

  6. Containerless high temperature property measurements by atomic fluorescence

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The use of laser induced fluorescence (LIF) techniques for containerless study of high temperature processes and material properties is studied. Gas jet and electromagnetic levitation and electromagnetic and laser heating techniques are used with LIF in Earth-based containerless high temperature experiments. The work to date includes development of an apparatus and its use in studies of chemical reactions on Al2O3, molybdenum, and tungsten specimens, novel methods for noncontact specimen temperature measurement, and levitation jet properties. Brief summaries of these studies are given. The apparatus is described and detailed results for the current reporting period are presented.

  7. ADVANCED APPROACHES TO ARSINE ATOMIZATION FOR AS SPECIATION BY CRYOFOCUSING WITH ATOMIC ABSORPTION AND ATOMIC FLUORESCENCE DETECTORS

    EPA Science Inventory

    Human metabolism of inorganic arsenic (iAs) yields methylated arsenicals that contain arsenic in +3 or +5 oxidation state. Trivalent methylated arsenicals are significantly more toxic than their pentavalent counterparts. Therefore, determination of tri- and pentavalent forms of m...

  8. Quantum state-resolved probing of strong-field-ionized xenon atoms using femtosecond high-order harmonic transient absorption spectroscopy.

    PubMed

    Loh, Zhi-Heng; Khalil, Munira; Correa, Raoul E; Santra, Robin; Buth, Christian; Leone, Stephen R

    2007-04-06

    Femtosecond high-order harmonic transient absorption spectroscopy is used to resolve the complete |j,m quantum state distribution of Xe+ produced by optical strong-field ionization of Xe atoms at 800 nm. Probing at the Xe N4/5 edge yields a population distribution rhoj,|m| of rho3/2,1/2ratiorho1/2,1/2ratiorho3/2,3/2=75+/-6 :12+/-3 :13+/-6%. The result is compared to a tunnel ionization calculation with the inclusion of spin-orbit coupling, revealing nonadiabatic ionization behavior. The sub-50-fs time resolution paves the way for tabletop extreme ultraviolet absorption probing of ultrafast dynamics.

  9. Atomic-scale distortion of optically activated Sm dopants identified with site-selective X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Ishii, Masashi; Crowe, Iain F.; Halsall, Matthew P.; Hamilton, Bruce; Hu, Yongfeng; Sham, Tsun-Kong; Harako, Susumu; Zhao, Xin-Wei; Komuro, Shuji

    2013-10-01

    The local structure of luminescent Sm dopants was investigated using an X-ray absorption fine-structure technique with X-ray-excited optical luminescence. Because this technique evaluates X-ray absorption from luminescence, only optically active sites are analyzed. The Sm L3 near-edge spectrum contains split 5d states and a shake-up transition that are specific to luminescent Sm. Theoretical calculations using cluster models identified an atomic-scale distortion that can reproduce the split 5d states. The model with C4v local symmetry and compressive bond length of Sm-O of a six-fold oxygen (SmO6) cluster is most consistent with the experimental results.

  10. Oxygen vacancy mediated enhanced photo-absorption from ZnO(0001) nanostructures fabricated by atom beam sputtering

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Solanki, Vanaraj; Joshi, Shalik R.; Mishra, Indrani

    2016-08-07

    The nanoscale patterns created on the ZnO(0001) surfaces during atom beam irradiation have been investigated here for their photo absorption response. Preferential sputtering, during irradiation, promotes Zn-rich zones that serve as the nucleation centers for the spontaneous creation of nanostructures. Nanostructured surfaces with bigger (78 nm) nanodots, displaying hexagonal ordering and long ranged periodic behavior, show higher photo absorption and a ∼0.09 eV reduced bandgap. These nanostructures also demonstrate higher concentration of oxygen vacancies which are crucial for these results. The enhanced photo-response, as observed here, has been achieved in the absence of any dopant elements.

  11. Approaching perfect absorption of monolayer molybdenum disulfide at visible wavelengths using critical coupling.

    PubMed

    Jiang, Xiaoyun; Wang, Tao; Xiao, Shuyuan; Yan, Xicheng; Cheng, Le; Zhong, Qingfang

    2018-08-17

    A simple perfect absorption structure is proposed to achieve the high efficiency light absorption of monolayer molybdenum disulfide (MoS 2 ) by the critical coupling mechanism of guided resonances. The results of numerical simulation and theoretical analysis show that the light absorption in this atomically thin layer can be as high as 98.3% at the visible wavelengths, which is over 12 times more than that of a bare monolayer MoS 2 . In addition, the operating wavelength can be tuned flexibly by adjusting the radius of the air hole and the thickness of the dielectric layers, which is of great practical significance to improve the efficiency and selectivity of the absorption in monolayer MoS 2 . The novel idea of using critical coupling to enhance the light-MoS 2 interaction can be also adopted in other atomically thin materials. The meaningful improvement and tunability of the absorption in monolayer MoS 2 provides a good prospect for the realization of high-performance MoS 2 -based optoelectronic applications, such as photodetection and photoluminescence.

  12. Specification of Butyltins and Methyltins in Seawater and Marine Sediments by Hydride Derivatization and Atomic Absorption Detection.

    DTIC Science & Technology

    1985-07-01

    Corporation . - P.F. Seligman . . Naval Ocean Systems Center fTW G. Vafa University of Hawaii Research Corporation P.M. Stang DEC 0 4 198 1: San Diego State...NAVFAC 032) under the Marine Environmental Quality Assessment Program. Released by Under authority of P. F. Seligman , Head S. Yamamoto, Head Marine...SEDIMENTS BY HYDRIDE DERIVATIZATION AND ATOMIC ABSORPTION DETECTION 12 PERSONAL AUJTHORWS) A. 0. Valkirs, P. F. Seligman , G. Vafa, P. M. Stang, V. Homner

  13. Major and trace element concentrations in samples from 72275 and 72255. [chemical composition of lunar rocks

    NASA Technical Reports Server (NTRS)

    Haskin, L. A.; Blanchard, D. P.; Korotev, R.; Jacobs, J. W.; Brannon, J. A.; Herrmann, A. G.

    1974-01-01

    Analytical data have been obtained for Co, Sc, Hf, Zn, Cr, Ga, Rb, Cs, Ni, major elements, and rare earth elements in eight samples from boulder 1. The data for trace elements were obtained by radiochemical neutron activation analysis. Major elements, except Na and Mn, were obtained by atomic absorption spectral photometry. Values for Na and Mn were obtained by neutron activation analysis of the same powder that was later dissolved to provide the atomic absorption analyses.

  14. Determination of traces of silicone defoamer in fruit juices by solvent extraction/atomic absorption spectroscopy.

    PubMed

    Gooch, E G

    1993-01-01

    Silicone defoamers are used to control foam during the processing of fruit juices. Residual silicones in fruit juices can be separated from the naturally occurring siliceous materials in fruit products and selectively recovered by solvent extraction, after suitable pretreatment. The recovered silicone is measured by atomic absorption spectroscopy. Silicone concentrations as low as about 1 ppm can be measured. The juices are accurately spiked for recovery studies by the addition of silicone dispersed in D-sorbitol.

  15. [Determination of mercury in Boletus impolitus by flow injection-atomic absorption spectrometry].

    PubMed

    Li, Tao; Wang, Yuan-Zhong

    2008-04-01

    Various test conditions and effect factors for the determination of mercury by flow injection-atomic absorption spectrometry were discussed, and a method for the determination of mercury in Boletus impolitus has been developed. The linear range for mercury is 0-60 microg x L(-1). The relative standard deviation is less than 3.0%, and the recovery is 96%-107%. This method is simple, rapid and has been applied to the determination of mercury in Boletus impolitus samples with satisfactory results.

  16. Determination of silver in irons and steels by atomic-absorption spectrometry with an induction furnace: Direct analysis of solid samples.

    PubMed

    Aziz-Alrahman, A M; Headridge, J B

    1978-07-01

    The silver contents of 17 irons and steels have been determined by dropping 0.5-20mg of millings or turnings of the metals into an induction furnace situated within an atomic-absorption spectrophotometer. The limit of detection was 0.005 mug/g and the relative standard deviations were 12% or better for silver contents of not less than 0.05 mug/g. Samples are added to the furnace at 4-5 min intervals.

  17. Development of a force sensor using atom interferometry to constrain theories on dark matter and dark energy

    NASA Astrophysics Data System (ADS)

    Schlupf, Chandler; Niederriter, Robert; Bohr, Eliot; Khamis, Sami; Park, Youna; Szwed, Erik; Hamilton, Paul

    2017-04-01

    Atom interferometry has been used in many precision measurements such as Newton's gravitational constant, the fine structure constant, and tests of the equivalence principle. We will perform atom interferometry in an optical lattice to measure the force felt by an atom due to a test mass in search of new forces suggested by dark matter and dark energy theories. We will be developing a new apparatus using laser-cooled ytterbium to continuously measure this force by observing their Bloch oscillations. Interfering atoms in an optical lattice allows continuous measurements in a small volume over a long period of time, enabling our device to be sensitive to time-varying forces while minimizing vibrational noise. We present the details of this experiment and the progress on it thus far.

  18. Investigation of an alternating current plasma as an element selective atomic emission detector for high-resolution capillary gas chromatography and as a source for atomic absorption and atomic emission spectrometry

    NASA Astrophysics Data System (ADS)

    Ombaba, Jackson M.

    This thesis deals with the construction and evaluation of an alternating current plasma (ACP) as an element-selective detector for high resolution capillary gas chromatography (GC) and as an excitation source for atomic absorption spectrometry (AAS) and atomic emission spectrometry (AES). The plasma, constrained in a quartz discharge tube at atmospheric pressure, is generated between two copper electrodes and utilizes helium as the plasma supporting gas. The alternating current plasma power source consists of a step-up transformer with a secondary output voltage of 14,000 V at a current of 23 mA. The device exhibits a stable signal because the plasma is self-seeding and reignites itself every half cycle. A tesla coil is not required to commence generation of the plasma if the ac voltage applied is greater than the breakdown voltage of the plasma-supporting gas. The chromatographic applications studied included the following: (1) the separation and selective detection of the organotin species, tributyltin chloride (TBT) and tetrabutyltin (TEBT), in environmental matrices including mussels (Mvutilus edullus) and sediment from Boston Harbor, industrial waste water and industrial sludge, and (2) the detection of methylcyclopentadienyl manganesetricarbonyl (MMT) and similar compounds used as gasoline additives. An ultrasonic nebulizer (common room humidifier) was utilized as a sample introduction device for aqueous solutions when the ACP was employed as an atomization source for atomic absorption spectrometry and as an excitation source for atomic emission spectrometry. Plasma diagnostic parameters studied include spatial electron number density across the discharge tube, electronic, excitation and ionization temperatures. Interference studies both in absorption and emission modes were also considered. Figures of merits of selected elements both in absorption and emission modes are reported. The evaluation of a computer-aided optimization program, Drylab GC, using spearmint oil and Environmental Protection Agency (EPA) standard mixture as probes is also discussed. The program supplied by LC Resources (Lafayette, CA) is used for separation optimization and prediction of gas chromatographic parameters. Column dead-time and average plate number were used as input data in conjunction with the retention times and peak areas of solutes at two different temperature programming rates. Once input data are entered into an IBM or IBM compatible personal computer, the program produces a 'relative resolution map' (RRM) which guides the analyst in selecting the most favorable temperature programming rate for the separation.

  19. Robust Accurate Non-Invasive Analyte Monitor

    DOEpatents

    Robinson, Mark R.

    1998-11-03

    An improved method and apparatus for determining noninvasively and in vivo one or more unknown values of a known characteristic, particularly the concentration of an analyte in human tissue. The method includes: (1) irradiating the tissue with infrared energy (400 nm-2400 nm) having at least several wavelengths in a given range of wavelengths so that there is differential absorption of at least some of the wavelengths by the tissue as a function of the wavelengths and the known characteristic, the differential absorption causeing intensity variations of the wavelengths incident from the tissue; (2) providing a first path through the tissue; (3) optimizing the first path for a first sub-region of the range of wavelengths to maximize the differential absorption by at least some of the wavelengths in the first sub-region; (4) providing a second path through the tissue; and (5) optimizing the second path for a second sub-region of the range, to maximize the differential absorption by at least some of the wavelengths in the second sub-region. In the preferred embodiment a third path through the tissue is provided for, which path is optimized for a third sub-region of the range. With this arrangement, spectral variations which are the result of tissue differences (e.g., melanin and temperature) can be reduced. At least one of the paths represents a partial transmission path through the tissue. This partial transmission path may pass through the nail of a finger once and, preferably, twice. Also included are apparatus for: (1) reducing the arterial pulsations within the tissue; and (2) maximizing the blood content i the tissue.

  20. 10 CFR 810.3 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... of neutrons used to effect SNM production in the “subcritical assembly.” Agreement for cooperation... International Atomic Energy Agency. Non-nuclear-weapon state is a country not recognized as a nuclear-weapon...-Proliferation of Nuclear Weapons. Nuclear reactor means an apparatus, other than a nuclear explosive device...

  1. 10 CFR 810.3 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... of neutrons used to effect SNM production in the “subcritical assembly.” Agreement for cooperation... International Atomic Energy Agency. Non-nuclear-weapon state is a country not recognized as a nuclear-weapon...-Proliferation of Nuclear Weapons. Nuclear reactor means an apparatus, other than a nuclear explosive device...

  2. Experimental station for ultrafast extreme ultraviolet spectroscopy for non-equilibrium dynamics in warm dense matter

    NASA Astrophysics Data System (ADS)

    Lee, Jong-won; Geng, Xiaotao; Jung, Jae Hyung; Cho, Min Sang; Yang, Seong Hyeok; Jo, Jawon; Lee, Chang-lyoul; Cho, Byoung Ick; Kim, Dong-Eon

    2018-07-01

    Recent interest in highly excited matter generated by intense femtosecond laser pulses has led to experimental methods that directly investigate ultrafast non-equilibrium electronic and structural dynamics. We present a tabletop experimental station for the extreme ultraviolet (EUV) spectroscopy used to trace L-edge dynamics in warm dense aluminum with a temporal resolution of a hundred femtoseconds. The system consists of the EUV probe generation part via a high-order harmonic generation process of femtosecond laser pulses with atomic clusters, a beamline with high-throughput optics and a sample-refreshment system of nano-foils utilizing the full repetition rate of the probe, and a flat-field EUV spectrograph. With the accumulation of an order of a hundred shots, a clear observation of the change in the aluminum L-shell absorption was achieved with a temporal resolution of 90 fs in a 600-fs window. The signature of a non-equilibrium electron distribution over a 10-eV range and its evolution to a 1-eV Fermi distribution are observed. This demonstrates the capability of this apparatus to capture the non-equilibrium electron-hole dynamics in highly excited warm dense matter conditions.

  3. Simultaneous multielement atomic absorption spectrometry with graphite furnace atomization

    NASA Astrophysics Data System (ADS)

    Harnly, James M.; Miller-Ihli, Nancy J.; O'Haver, Thomas C.

    The extended analytical range capability of a simultaneous multielement atomic absorption continuum source spectrometer (SIMAAC) was tested for furnace atomization with respect to the signal measurement mode (peak height and area), the atomization mode (from the wall or from a platform), and the temperature program mode (stepped or ramped atomization). These parameters were evaluated with respect to the shapes of the analytical curves, the detection limits, carry-over contamination and accuracy. Peak area measurements gave more linear calibration curves. Methods for slowing the atomization step heating rate, the use of a ramped temperature program or a platform, produced similar calibration curves and longer linear ranges than atomization with a stepped temperature program. Peak height detection limits were best using stepped atomization from the wall. Peak area detection limits for all atomization modes were similar. Carry-over contamination was worse for peak area than peak height, worse for ramped atomization than stepped atomization, and worse for atomization from a platform than from the wall. Accurate determinations (100 ± 12% for Ca, Cu, Fe, Mn, and Zn in National Bureau of Standards' Standard Reference Materials Bovine Liver 1577 and Rice Flour 1568 were obtained using peak area measurements with ramped atomization from the wall and stepped atomization from a platform. Only stepped atomization from a platform gave accurate recoveries for K. Accurate recoveries, 100 ± 10%, with precisions ranging from 1 to 36 % (standard deviation), were obtained for the determination of Al, Co, Cr, Fe, Mn, Mo, Ni. Pb, V and Zn in Acidified Waters (NBS SRM 1643 and 1643a) using stepped atomization from a platform.

  4. Identification of F impurities in F-doped ZnO by synchrotron X-ray absorption near edge structures

    NASA Astrophysics Data System (ADS)

    Na-Phattalung, Sutassana; Limpijumnong, Sukit; Min, Chul-Hee; Cho, Deok-Yong; Lee, Seung-Ran; Char, Kookrin; Yu, Jaejun

    2018-04-01

    Synchrotron X-ray absorption near edge structure (XANES) measurements of F K-edge in conjunction with first-principles calculations are used to identify the local structure of the fluorine (F) atom in F-doped ZnO. The ZnO film was grown by pulsed laser deposition with an Nd:YAG laser, and an oxyfluoridation method was used to introduce F ions into the ZnO films. The measured XANES spectrum of the sample was compared against the first-principles XANES calculations based on various models for local atomic structures surrounding F atoms. The observed spectral features are attributed to ZnF2 and FO defects in wurtzite bulk ZnO.

  5. Measurements of sulfur compounds in CO 2 by diode laser atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Franzke, J.; Stancu, D. G.; Niemax, K.

    2003-07-01

    Two simple methods for the analysis of the total concentration of sulfur in CO 2 by diode laser atomic absorption spectrometry of excited, metastable sulfur atoms in a direct current discharge are presented. In the first method, the CO 2 sample gas is mixed with the plasma gas (Ar or He) while the second is based on reproducible measurements of the sulfur released from the walls in a helium discharge after being deposited as a result of operating the discharge in pure CO 2 sample gas. The detection limits obtained satisfy the requirements for the control of sulfur compounds in CO 2 used in the food and beverage industry.

  6. Statistical evaluation of an inductively coupled plasma atomic emission spectrometric method for routine water quality testing

    USGS Publications Warehouse

    Garbarino, J.R.; Jones, B.E.; Stein, G.P.

    1985-01-01

    In an interlaboratory test, inductively coupled plasma atomic emission spectrometry (ICP-AES) was compared with flame atomic absorption spectrometry and molecular absorption spectrophotometry for the determination of 17 major and trace elements in 100 filtered natural water samples. No unacceptable biases were detected. The analysis precision of ICP-AES was found to be equal to or better than alternative methods. Known-addition recovery experiments demonstrated that the ICP-AES determinations are accurate to between plus or minus 2 and plus or minus 10 percent; four-fifths of the tests yielded average recoveries of 95-105 percent, with an average relative standard deviation of about 5 percent.

  7. Electromagnetically induced absorption and transparency in degenerate two level systems of metastable Kr atoms and measurement of Landé g-factor

    NASA Astrophysics Data System (ADS)

    Kale, Y. B.; Tiwari, V. B.; Mishra, S. R.; Singh, S.; Rawat, H. S.

    2016-12-01

    We report electromagnetically induced absorption (EIA) and transparency (EIT) resonances of sub-natural linewidth in degenerate two level systems (DTLSs) of metastable 84Kr (84Kr*) and 83Kr (83Kr*) atoms. Using the spectrally narrow EIA signals obtained corresponding to the closed hyperfine transition 4p55s[3/2]2(F=13/2) to 4p55p[5/2]3(F‧ = 15 / 2) in 83Kr* atom, we have measured the Landé g-factor (gF) for the lower hyperfine level involved in this transition by application of small values of magnetic field of few Gauss.

  8. Exploration geochemical technique for the determination of preconcentrated organometallic halides by ICP-AES

    USGS Publications Warehouse

    Motooka, J.M.

    1988-01-01

    An atomic absorption extraction technique which is widely used in geochemical exploration for the determination of Ag, As, Au, Bi, Cd, Cu, Mo, Pb, Sb, and Zn has been modified and adapted to a simultaneous inductively coupled plasma-atomic emission instrument. the experimental and operating parameters are described for the preconcentration of the metals into their organometallic halides and for the determination of the metals. Lower limits of determination are equal to or improved over those for flame atomic absorption (except Au) and ICP results are very similar to the accepted AA values, with precision for the ICP data in excess of that necessary for exploration purposes.

  9. TheoReTS - An information system for theoretical spectra based on variational predictions from molecular potential energy and dipole moment surfaces

    NASA Astrophysics Data System (ADS)

    Rey, Michaël; Nikitin, Andrei V.; Babikov, Yurii L.; Tyuterev, Vladimir G.

    2016-09-01

    Knowledge of intensities of rovibrational transitions of various molecules and theirs isotopic species in wide spectral and temperature ranges is essential for the modeling of optical properties of planetary atmospheres, brown dwarfs and for other astrophysical applications. TheoReTS ("Theoretical Reims-Tomsk Spectral data") is an Internet accessible information system devoted to ab initio based rotationally resolved spectra predictions for some relevant molecular species. All data were generated from potential energy and dipole moment surfaces computed via high-level electronic structure calculations using variational methods for vibration-rotation energy levels and transitions. When available, empirical corrections to band centers were applied, all line intensities remaining purely ab initio. The current TheoReTS implementation contains information on four-to-six atomic molecules, including phosphine, methane, ethylene, silane, methyl-fluoride, and their isotopic species 13CH4 , 12CH3D , 12CH2D2 , 12CD4 , 13C2H4, … . Predicted hot methane line lists up to T = 2000 K are included. The information system provides the associated software for spectra simulation including absorption coefficient, absorption and emission cross-sections, transmittance and radiance. The simulations allow Lorentz, Gauss and Voight line shapes. Rectangular, triangular, Lorentzian, Gaussian, sinc and sinc squared apparatus function can be used with user-defined specifications for broadening parameters and spectral resolution. All information is organized as a relational database with the user-friendly graphical interface according to Model-View-Controller architectural tools. The full-featured web application is written on PHP using Yii framework and C++ software modules. In case of very large high-temperature line lists, a data compression is implemented for fast interactive spectra simulations of a quasi-continual absorption due to big line density. Applications for the TheoReTS may include: education/training in molecular absorption/emission, radiative and non-LTE processes, spectroscopic applications, opacity calculations for planetary and astrophysical applications. The system is freely accessible via internet on the two mirror sites: in Reims, France

  10. Local atomic and electronic structures of epitaxial strained LaCoO3 thin films

    NASA Astrophysics Data System (ADS)

    Sterbinsky, G. E.; Ryan, P. J.; Kim, J.-W.; Karapetrova, E.; Ma, J. X.; Shi, J.; Woicik, J. C.

    2012-01-01

    We have examined the atomic and electronic structures of perovskite lanthanum cobaltite (LaCoO3) thin films using Co K-edge x-ray absorption fine structure (XAFS) spectroscopy. Extended XAFS (EXAFS) demonstrates that a large difference between in-plane and out-of-plane Co-O bond lengths results from tetragonal distortion in highly strained films. The structural distortions are strongly coupled to the hybridization between atomic orbitals of the Co and O atoms, as shown by x-ray absorption near edge spectroscopy (XANES). Our results indicate that increased hybridization is not the cause of ferromagnetism in strained LaCoO3 films. Instead, we suggest that the strain-induced distortions of the oxygen octahedra increase the population of eg electrons and concurrently depopulate t2g electrons beyond a stabilization threshold for ferromagnetic order.

  11. The Electronic Structure and Optical Properties of Anatase TiO₂ with Rare Earth Metal Dopants from First-Principles Calculations.

    PubMed

    Xie, Kefeng; Jia, Qiangqiang; Wang, Yizhe; Zhang, Wenxue; Xu, Jingcheng

    2018-01-24

    The electronic and optical properties of the rare earth metal atom-doped anatase TiO₂ have been investigated systematically via density functional theory calculations. The results show that TiO₂ doped by Ce or Pr is the optimal choice because of its small band gap and strong optical absorption. Rare earth metal atom doping induces several impurity states that tune the location of valence and conduction bands and an obvious lattice distortion that should reduce the probability of electron-hole recombination. This effect of band change originates from the 4 f electrons of the rare earth metal atoms, which leads to an improved visible light absorption. This finding indicates that the electronic structure of anatase TiO₂ is tuned by the introduction of impurity atoms.

  12. The Electronic Structure and Optical Properties of Anatase TiO2 with Rare Earth Metal Dopants from First-Principles Calculations

    PubMed Central

    Xie, Kefeng; Jia, Qiangqiang; Wang, Yizhe; Zhang, Wenxue; Xu, Jingcheng

    2018-01-01

    The electronic and optical properties of the rare earth metal atom-doped anatase TiO2 have been investigated systematically via density functional theory calculations. The results show that TiO2 doped by Ce or Pr is the optimal choice because of its small band gap and strong optical absorption. Rare earth metal atom doping induces several impurity states that tune the location of valence and conduction bands and an obvious lattice distortion that should reduce the probability of electron–hole recombination. This effect of band change originates from the 4f electrons of the rare earth metal atoms, which leads to an improved visible light absorption. This finding indicates that the electronic structure of anatase TiO2 is tuned by the introduction of impurity atoms. PMID:29364161

  13. Flow injection analysis-flame atomic absorption spectrometry system for indirect determination of sulfite after on-line reduction of solid-phase manganese (IV) dioxide reactor.

    PubMed

    Zare-Dorabei, Rouholah; Boroun, Shokoufeh; Noroozifar, Meissam

    2018-02-01

    A new and simple flow injection method followed by atomic absorption spectrometry was developed for indirect determination of sulfite. The proposed method is based on the oxidation of sulfite to sulphate ion using solid-phase manganese dioxide (30% W/W suspended on silica gel beads) reactor. MnO 2 will be reduced to Mn(II) by sample injection in to the column under acidic carrier stream of HNO 3 (pH 2) with flow rate of 3.5mLmin -1 at room temperature. Absorption measurement of Mn(II) which is proportional to the concentration of sulfite in the sample was carried out by atomic absorption spectrometry. The calibration curve was linear up to 25mgL -1 with a detection limit (DL) of 0.08mgL -1 for 400µL injection sample volume. The presented method is efficient toward sulfite determination in sugar and water samples with a relative standard deviation (RSD) less than 1.2% and a sampling rate of about 60h -1 . Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Evaluation of Low-Earth-Orbit Environmental Effects on International Space Station Thermal Control Materials

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.

    1998-01-01

    Many spacecraft thermal control coatings in low Earth orbit (LEO) can be affected by solar ultraviolet radiation and atomic oxygen. Ultraviolet radiation can darken some polymers and oxides commonly used in thermal control materials. Atomic oxygen can erode polymer materials, but it may reverse the ultraviolet-darkening effect on oxides. Maintaining the desired solar absorptance for thermal control coatings is important to assure the proper operating temperature of the spacecraft. Thermal control coatings to be used on the International Space Station (ISS) were evaluated for their performance after exposure in the NASA Lewis Research Center's Atomic Oxygen-Vacuum Ultraviolet Exposure (AO-VUV) facility. This facility simulated the LEO environments of solar vacuum ultraviolet (VUV) radiation (wavelength range, 115 to 200 nanometers (nm)) and VUV combined with atomic oxygen. Solar absorptance was measured in vacuo to eliminate the "bleaching" effects of ambient oxygen on VUV-induced degradation. The objective of these experiments was to determine solar absorptance increases of various thermal control materials due to exposure to simulated LEO conditions similar to those expected for ISS. Work was done in support of ISS efforts at the requests of Boeing Space and Defense Systems and Lockheed Martin Vought Systems.

  15. Development and Validation of a Sensitive Method for Trace Nickel Determination by Slotted Quartz Tube Flame Atomic Absorption Spectrometry After Dispersive Liquid-Liquid Microextraction.

    PubMed

    Yolcu, Şükran Melda; Fırat, Merve; Chormey, Dotse Selali; Büyükpınar, Çağdaş; Turak, Fatma; Bakırdere, Sezgin

    2018-05-01

    In this study, dispersive liquid-liquid microextraction was systematically optimized for the preconcentration of nickel after forming a complex with diphenylcarbazone. The measurement output of the flame atomic absorption spectrometer was further enhanced by fitting a custom-cut slotted quartz tube to the flame burner head. The extraction method increased the amount of nickel reaching the flame and the slotted quartz tube increased the residence time of nickel atoms in the flame to record higher absorbance. Two methods combined to give about 90 fold enhancement in sensitivity over the conventional flame atomic absorption spectrometry. The optimized method was applicable over a wide linear concentration range, and it gave a detection limit of 2.1 µg L -1 . Low relative standard deviations at the lowest concentration in the linear calibration plot indicated high precision for both extraction process and instrumental measurements. A coal fly ash standard reference material (SRM 1633c) was used to determine the accuracy of the method, and experimented results were compatible with the certified value. Spiked recovery tests were also used to validate the applicability of the method.

  16. An Inexpensive High Pressure Optical Absorption Cell for IR-VIS-UV Studies.

    ERIC Educational Resources Information Center

    Rodgers, V. E.; Angell, C. A.

    1983-01-01

    Describes an optical cell, suitable for high-pressure studies between at least -130 and +150 degrees Celsius, which may be assembled for about $50. Discusses experimental demonstration of principles involved when using the apparatus, including effects of pressure on coordination of ions in solution and on reaction rates in solution. (JN)

  17. Laser-Beam-Absorption Chemical-Species Monitor

    NASA Technical Reports Server (NTRS)

    Gersh, Michael; Goldstein, Neil; Lee, Jamine; Bien, Fritz; Richtsmeier, Steven

    1996-01-01

    Apparatus measures concentration of chemical species in fluid medium (e.g., gaseous industrial process stream). Directs laser beam through medium, and measures intensity of beam after passage through medium. Relative amount of beam power absorbed in medium indicative of concentration of chemical species; laser wavelength chosen to be one at which species of interest absorbs.

  18. Apparatus and method for transient thermal infrared spectrometry of flowable enclosed materials

    DOEpatents

    McClelland, John F.; Jones, Roger W.

    1993-03-02

    A method and apparatus for enabling analysis of a flowable material enclosed in a transport system having an infrared transparent wall portion. A temperature differential is transiently generated between a thin surface layer portion of the material and a lower or deeper portion of the material sufficient to alter the thermal infrared emission spectrum of the material from the black-body thermal infrared emission spectrum of the material, and the altered thermal infrared emission spectrum is detected through the infrared transparent portion of the transport system while the altered thermal infrared emission spectrum is sufficiently free of self-absorption by the material of emitted infrared radiation. The detection is effected prior to the temperature differential propagating into the lower or deeper portion of the material to an extent such that the altered thermal infrared emission spectrum is no longer sufficiently free of self-absorption by the material of emitted infrared radiation. By such detection, the detected altered thermal infrared emission spectrum is indicative of characteristics relating to molecular composition of the material.

  19. Self-assembly based plasmonic arrays tuned by atomic layer deposition for extreme visible light absorption.

    PubMed

    Hägglund, Carl; Zeltzer, Gabriel; Ruiz, Ricardo; Thomann, Isabell; Lee, Han-Bo-Ram; Brongersma, Mark L; Bent, Stacey F

    2013-07-10

    Achieving complete absorption of visible light with a minimal amount of material is highly desirable for many applications, including solar energy conversion to fuel and electricity, where benefits in conversion efficiency and economy can be obtained. On a fundamental level, it is of great interest to explore whether the ultimate limits in light absorption per unit volume can be achieved by capitalizing on the advances in metamaterial science and nanosynthesis. Here, we combine block copolymer lithography and atomic layer deposition to tune the effective optical properties of a plasmonic array at the atomic scale. Critical coupling to the resulting nanocomposite layer is accomplished through guidance by a simple analytical model and measurements by spectroscopic ellipsometry. Thereby, a maximized absorption of light exceeding 99% is accomplished, of which up to about 93% occurs in a volume-equivalent thickness of gold of only 1.6 nm. This corresponds to a record effective absorption coefficient of 1.7 × 10(7) cm(-1) in the visible region, far exceeding those of solid metals, graphene, dye monolayers, and thin film solar cell materials. It is more than a factor of 2 higher than that previously obtained using a critically coupled dye J-aggregate, with a peak width exceeding the latter by 1 order of magnitude. These results thereby substantially push the limits for light harvesting in ultrathin, nanoengineered systems.

  20. Alternating absorption features during attosecond-pulse propagation in a laser-controlled gaseous medium

    NASA Astrophysics Data System (ADS)

    Pfeiffer, Adrian N.; Bell, M. Justine; Beck, Annelise R.; Mashiko, Hiroki; Neumark, Daniel M.; Leone, Stephen R.

    2013-11-01

    Recording the transmitted spectrum of a weak attosecond pulse through a medium, while a strong femtosecond pulse copropagates at variable delay, probes the strong-field dynamics of atoms, molecules, and solids. Usually, the interpretation of these measurements is based on the assumption of a thin medium. Here, the propagation through a macroscopic medium of helium atoms in the region of fully allowed resonances is investigated both theoretically and experimentally. The propagation has dramatic effects on the transient spectrum even at relatively low pressures (50 mbar) and short propagation lengths (1 mm). The absorption does not evolve monotonically with the product of propagation distance and pressure, but regions with characteristics of Lorentz line shapes and characteristics of Fano line shapes alternate. Criteria are deduced to estimate whether macroscopic effects can be neglected or not in a transient absorption experiment. Furthermore, the theory in the limit of single-atom response yields a general equation for Lorentz- and Fano-type line shapes at variable pulse delay.

  1. Matrix modification with silver for the electrothermal atomization of arsenic and selenium

    USGS Publications Warehouse

    Sanzolone, R.F.; Chao, T.T.

    1981-01-01

    Silver as a matrix modifier is shown to improve the carbon-rod atomization of both arsenic and selenium for atomic absorption spectrometry. Compared to nickel, the efficiency of silver is greater for arsenic and about the same for selenium. Silver fulfils two functions in its reaction, namely stabilization during the ashing stage and enhancement of absorbance in the final atomization. ?? 1981.

  2. 10 CFR 50.2 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... to bring and maintain the plant in safe shutdown (non-design basis accident). Applicant means a... Document Control Desk. Nuclear reactor means an apparatus, other than an atomic weapon, designed or used to... from the Restricted Data category pursuant to section 142 of the Act. Safe shutdown (non-design basis...

  3. 10 CFR 50.2 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... to bring and maintain the plant in safe shutdown (non-design basis accident). Applicant means a... Document Control Desk. Nuclear reactor means an apparatus, other than an atomic weapon, designed or used to... from the Restricted Data category pursuant to section 142 of the Act. Safe shutdown (non-design basis...

  4. 10 CFR 50.2 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... to bring and maintain the plant in safe shutdown (non-design basis accident). Applicant means a... Document Control Desk. Nuclear reactor means an apparatus, other than an atomic weapon, designed or used to... from the Restricted Data category pursuant to section 142 of the Act. Safe shutdown (non-design basis...

  5. 10 CFR 50.2 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... to bring and maintain the plant in safe shutdown (non-design basis accident). Applicant means a... Document Control Desk. Nuclear reactor means an apparatus, other than an atomic weapon, designed or used to... from the Restricted Data category pursuant to section 142 of the Act. Safe shutdown (non-design basis...

  6. Materials selection for long life in LEO: A critical evaluation of atomic oxygen testing with thermal atom systems

    NASA Technical Reports Server (NTRS)

    Koontz, S. L.; Kuminecz, J.; Leger, L.; Nordine, P.

    1988-01-01

    The use of thermal atom test methods as a materials selection and screening technique for low-Earth orbit (LEO) spacecraft is critically evaluated. The chemistry and physics of thermal atom environments are compared with the LEO environment. The relative reactivities of a number of materials determined to be in thermal atom environments are compared to those observed in LEO and in high quality LEO simulations. Reaction efficiencies measured in a new type of thermal atom apparatus are one-hundredth to one-thousandth those observed in LEO, and many materials showing nearly identical reactivities in LEO show relative reactivities differing by as much as a factor of 8 in thermal atom systems. A simple phenomenological kinetic model for the reaction of oxygen atoms with organic materials can be used to explain the differences in reactivity in different environments. Certain specific thermal test environments can be used as reliable materials screening tools. Using thermal atom methods to predict material lifetime in LEO requires direct calibration of the method against LEO data or high quality simulation data for each material.

  7. Carbon X-ray absorption in the local ISM: fingerprints in X-ray Novae spectra

    NASA Astrophysics Data System (ADS)

    Gatuzz, Efraín; Ness, J.-U.; Gorczyca, T. W.; Hasoglu, M. F.; Kallman, Timothy R.; García, Javier A.

    2018-06-01

    We present a study of the C K-edge using high-resolution LETGS Chandra spectra of four novae during their super-soft-source (SSS) phase. We identified absorption lines due to C II Kα, C III Kα and C III Kβ resonances. We used these astronomical observations to perform a benchmarking of the atomic data, which involves wavelength shifts of the resonances and photoionization cross-sections. We used improved atomic data to estimate the C II and C III column densities. The absence of physical shifts for the absorption lines, the consistence of the column densities between multiple observations and the high temperature required for the SSS nova atmosphere modeling support our conclusion about an ISM origin of the respective absorption lines. Assuming a collisional ionization equilibrium plasma the maximum temperature derived from the ratio of C II/C III column densities of the absorbers correspond to Tmax < 3.05 × 104 K.

  8. Towards simultaneous measurements of electronic and structural properties in ultra-fast x-ray free electron laser absorption spectroscopy experiments

    NASA Astrophysics Data System (ADS)

    Gaudin, J.; Fourment, C.; Cho, B. I.; Engelhorn, K.; Galtier, E.; Harmand, M.; Leguay, P. M.; Lee, H. J.; Nagler, B.; Nakatsutsumi, M.; Ozkan, C.; Störmer, M.; Toleikis, S.; Tschentscher, Th; Heimann, P. A.; Dorchies, F.

    2014-04-01

    The rapidly growing ultrafast science with X-ray lasers unveils atomic scale processes with unprecedented time resolution bringing the so called ``molecular movie'' within reach. X-ray absorption spectroscopy is one of the most powerful x-ray techniques providing both local atomic order and electronic structure when coupled with ad-hoc theory. Collecting absorption spectra within few x-ray pulses is possible only in a dispersive setup. We demonstrate ultrafast time-resolved measurements of the LIII-edge x-ray absorption near-edge spectra of irreversibly laser excited Molybdenum using an average of only few x-ray pulses with a signal to noise ratio limited only by the saturation level of the detector. The simplicity of the experimental set-up makes this technique versatile and applicable for a wide range of pump-probe experiments, particularly in the case of non-reversible processes.

  9. Towards simultaneous measurements of electronic and structural properties in ultra-fast x-ray free electron laser absorption spectroscopy experiments

    PubMed Central

    Gaudin, J.; Fourment, C.; Cho, B. I.; Engelhorn, K.; Galtier, E.; Harmand, M.; Leguay, P. M.; Lee, H. J.; Nagler, B.; Nakatsutsumi, M.; Ozkan, C.; Störmer, M.; Toleikis, S.; Tschentscher, Th; Heimann, P. A.; Dorchies, F.

    2014-01-01

    The rapidly growing ultrafast science with X-ray lasers unveils atomic scale processes with unprecedented time resolution bringing the so called “molecular movie” within reach. X-ray absorption spectroscopy is one of the most powerful x-ray techniques providing both local atomic order and electronic structure when coupled with ad-hoc theory. Collecting absorption spectra within few x-ray pulses is possible only in a dispersive setup. We demonstrate ultrafast time-resolved measurements of the LIII-edge x-ray absorption near-edge spectra of irreversibly laser excited Molybdenum using an average of only few x-ray pulses with a signal to noise ratio limited only by the saturation level of the detector. The simplicity of the experimental set-up makes this technique versatile and applicable for a wide range of pump-probe experiments, particularly in the case of non-reversible processes. PMID:24740172

  10. Resonant Doppler velocimeter. Ph.D. Thesis. Final Report, 1 Jul. 1974 - 31 Oct. 1979; [velocity, temperature, and pressure measurement

    NASA Technical Reports Server (NTRS)

    Zimmermann, M.

    1980-01-01

    A technique is presented for visualizing and quantitatively measuring velocity, temperature, and pressure by shining a single frequency laser beam into a gaseous flow which is seeded with an atomic species. The laser is tuned through the absorption frequencies of the seeded species and the absorption profile is detected by observing fluorescence as the atoms relax back to the ground state. The flow velocity is determined by observing the Doppler shift in the absorption frequency. Spectroscopic absorption line broadening mechanisms furnish information regarding the static temperature and pressure of the moving gas. Results of experiments conducted in the free stream and in the bow shock of a conical model mounted in a hypersonic wind tunnel indicate that the experimental uncertainties in the measurement of average values for the velocity, temperature and pressure of the flow are 0.1, 5 and 10 percent respectively.

  11. Towards simultaneous measurements of electronic and structural properties in ultra-fast x-ray free electron laser absorption spectroscopy experiments

    DOE PAGES

    Gaudin, J.; Fourment, C.; Cho, B. I.; ...

    2014-04-17

    The rapidly growing ultrafast science with X-ray lasers unveils atomic scale processes with unprecedented time resolution bringing the so called “molecular movie” within reach. X-ray absorption spectroscopy is one of the most powerful x-ray techniques providing both local atomic order and electronic structure when coupled with ad-hoc theory. Collecting absorption spectra within few x-ray pulses is possible only in a dispersive setup. We demonstrate ultrafast time-resolved measurements of the LIII-edge x-ray absorption near-edge spectra of irreversibly laser excited Molybdenum using an average of only few x-ray pulses with a signal to noise ratio limited only by the saturation level ofmore » the detector. The simplicity of the experimental set-up makes this technique versatile and applicable for a wide range of pump-probe experiments, particularly in the case of non-reversible processes.« less

  12. Comparison of femtosecond- and nanosecond-two-photon-absorption laser-induced fluorescence (TALIF) of atomic oxygen in atmospheric-pressure plasmas

    NASA Astrophysics Data System (ADS)

    Schmidt, Jacob B.; Sands, Brian; Scofield, James; Gord, James R.; Roy, Sukesh

    2017-05-01

    Absolute number densities of atomic species produced by nanosecond (ns)-duration, repetitively pulsed electric discharges are measured by two-photon-absorption laser-induced fluorescence (TALIF). Unique to this work is the development of femtosecond-laser-based TALIF (fs-TALIF) that offers a number of advantages over more conventional nanosecond (ns)-pulse-duration laser techniques, such as higher-fidelity quenching rate measurements over a wide pressure range, significantly reduced photolytic interference (including photo-dissociation and photo-ionization), ability to collect two-dimensional images of atomic-species number densities with high spatial resolution aided by higher signal level, and efficient and accurate measurements of atomic-species number densities due to the higher repetition rates of the laser. For full quantification of these advantages, atomic-oxygen TALIF signals are collected from an atmospheric-pressure plasma jet employing both ns- and fs-duration laser-excitation pulses and the results are compared and contrasted.

  13. Temperature-controlled electrothermal atomization-atomic absorption spectrometry using a pyrometric feedback system in conjunction with a background monitoring device

    NASA Astrophysics Data System (ADS)

    Van Deijck, W.; Roelofsen, A. M.; Pieters, H. J.; Herber, R. F. M.

    The construction of a temperature-controlled feedback system for electrothermal atomization-atomic absorption spectrometry (ETA-AAS) using an optical pyrometer applied to the atomization stage is described. The system was used in conjunction with a fast-response background monitoring device. The heating rate of the furnace amounted to 1400° s -1 with a reproducibility better than 1%. The precision of the temperature control at a steady state temperature of 2000°C was 0.1%. The analytical improvements offered by the present system have been demonstrated by the determination of cadmium and lead in blood and finally by the determination of lead in serum. Both the sensitivity and the precision of the method have been improved. The accuracy of the method was checked by determining the lead content for a number of scrum samples both by ETA-AAS and differential pulse anodic stripping voltametry (DPASV) and proved to be satisfactory.

  14. Method and apparatus for monitoring the flow of mercury in a system

    DOEpatents

    Grossman, Mark W.

    1987-01-01

    An apparatus and method for monitoring the flow of mercury in a system. The equipment enables the entrainment of the mercury in a carrier gas e.g., an inert gas, which passes as mercury vapor between a pair of optically transparent windows. The attenuation of the emission is indicative of the quantity of mercury (and its isotopes) in the system. A 253.7 nm light is shone through one of the windows and the unabsorbed light is detected through the other window. The absorption of the 253.7 nm light is thereby measured whereby the quantity of mercury passing between the windows can be determined. The apparatus includes an in-line sensor for measuring the quantity of mercury. It includes a conduit together with a pair of apertures disposed in a face to face relationship and arranged on opposite sides of the conduit. A pair of optically transparent windows are disposed upon a pair of viewing tubes. A portion of each of the tubes is disposed inside of the conduit and within each of the apertures. The two windows are disposed in a face to face relationship on the ends of the viewing tubes and the entire assembly is hermetically sealed from the atmosphere whereby when 253.7 nm ultraviolet light is shone through one of the windows and detected through the other, the quantity of mercury which is passing by can be continuously monitored due to absorption which is indicated by attenuation of the amplitude of the observed emission.

  15. On-line ion-exchange preconcentration and determination of traces of platinum by electrothermal atomic absorption spectrometry.

    PubMed

    González García, M M; Sánchez Rojas, F; Bosch Ojeda, C; García de Torres, A; Cano Pavón, J M

    2003-04-01

    A method to determine trace amounts of platinum in different samples based on electrothermal atomic absorption spectrometry is described. The preconcentration step is performed on a chelating resin microcolumn [1,5-bis(2-pyridyl)-3-sulfophenyl methylene thiocarbonohydrazide (PSTH) immobilized on an anion-exchange resin (Dowex 1x8-200)] placed in the autosampler arm. The combination of a peristaltic pump for sample loading and the atomic absorption spectrometer pumps for elution through a selection valve simplifies the hardware. The peristaltic pump and the selection valve are easily controlled electronically with two switches placed in the autosampler, which are activated when the autosampler arm is down. Thus, the process is fully automated without any modification of the software of the atomic absorption spectrometer. Under the optimum conditions with a 60-s preconcentration time, a sample flow rate of 2.4 mL min(-1), and an injection volume of eluent of 40 microL, a linear calibration graph was obtained in the range 0-100 ng mL(-1). The enrichment factor was 14. The detection limit under these conditions is 1 ng mL(-1), and the relative standard deviation (RSD) is 1.6% for 10 ng mL(-1) of Pt. The method has been applied to the determination of platinum in catalyst, vegetation, soil, and natural water samples. The results showed good agreement with the certified value and the recoveries of Pt added to samples were 98-105%.

  16. Atomic Data Revisions for Transitions Relevant to Observations of Interstellar, Circumgalactic, and Intergalactic Matter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cashman, Frances H.; Kulkarni, Varsha P.; Kisielius, Romas

    2017-05-01

    Measurements of element abundances in galaxies from astrophysical spectroscopy depend sensitively on the atomic data used. With the goal of making the latest atomic data accessible to the community, we present a compilation of selected atomic data for resonant absorption lines at wavelengths longward of 911.753 Å (the H i Lyman limit), for key heavy elements (heavier than atomic number 5) of astrophysical interest. In particular, we focus on the transitions of those ions that have been observed in the Milky Way interstellar medium (ISM), the circumgalactic medium (CGM) of the Milky Way and/or other galaxies, and the intergalactic mediummore » (IGM). We provide wavelengths, oscillator strengths, associated accuracy grades, and references to the oscillator strength determinations. We also attempt to compare and assess the recent oscillator strength determinations. For about 22% of the lines that have updated oscillator strength values, the differences between the former values and the updated ones are ≳0.1 dex. Our compilation will be a useful resource for absorption line studies of the ISM, as well as studies of the CGM and IGM traced by sight lines to quasars and gamma-ray bursts. Studies (including those enabled by future generations of extremely large telescopes) of absorption by galaxies against the light of background galaxies will also benefit from our compilation.« less

  17. Deep seawater inherent optical properties in the Southern Ionian Sea

    NASA Astrophysics Data System (ADS)

    Riccobene, G.; Capone, A.; Aiello, S.; Ambriola, M.; Ameli, F.; Amore, I.; Anghinolfi, M.; Anzalone, A.; Avanzini, C.; Barbarino, G.; Barbarito, E.; Battaglieri, M.; Bellotti, R.; Beverini, N.; Bonori, M.; Bouhadef, B.; Brescia, M.; Cacopardo, G.; Cafagna, F.; Caponetto, L.; Castorina, E.; Ceres, A.; Chiarusi, T.; Circella, M.; Cocimano, R.; Coniglione, R.; Cordelli, M.; Costa, M.; Cuneo, S.; D'Amico, A.; de Bonis, G.; de Marzo, C.; de Rosa, G.; de Vita, R.; Distefano, C.; Falchini, E.; Fiorello, C.; Flaminio, V.; Fratini, K.; Gabrielli, A.; Galeotti, S.; Gandolfi, E.; Grimaldi, A.; Habel, R.; Leonora, E.; Lonardo, A.; Longo, G.; Lo Presti, D.; Lucarelli, F.; Maccioni, E.; Margiotta, A.; Martini, A.; Masullo, R.; Megna, R.; Migneco, E.; Mongelli, M.; Montaruli, T.; Morganti, M.; Musumeci, M.; Nicolau, C. A.; Orlando, A.; Osipenko, M.; Osteria, G.; Papaleo, R.; Pappalardo, V.; Petta, C.; Piattelli, P.; Raffaelli, F.; Raia, G.; Randazzo, N.; Reito, S.; Ricco, G.; Ripani, M.; Rovelli, A.; Ruppi, M.; Russo, G. V.; Russo, S.; Russo, S.; Sapienza, P.; Sedita, M.; Schuller, J.-P.; Shirokov, E.; Simeone, F.; Sipala, V.; Spurio, M.; Taiuti, M.; Terreni, G.; Trasatti, L.; Urso, S.; Valente, V.; Vicini, P.

    2007-02-01

    The NEMO (NEutrino Mediterranean Observatory) Collaboration has been carrying out since 1998 an evaluation programme of deep sea sites suitable for the construction of the future Mediterranean km3 Čerenkov neutrino telescope. We investigated the seawater optical and oceanographic properties of several deep sea marine areas close to the Italian Coast. Inherent optical properties (light absorption and attenuation coefficients) have been measured as a function of depth using an experimental apparatus equipped with standard oceanographic probes and the commercial transmissometer AC9 manufactured by WETLabs. This paper reports on the visible light absorption and attenuation coefficients measured in deep seawater of a marine region located in the Southern Ionian Sea, 60 100 km SE of Capo Passero (Sicily). Data show that blue light absorption coefficient is about 0.015 m-1 (corresponding to an absorption length of 67 m) close to the one of optically pure water and it does not show seasonal variation.

  18. Method of and apparatus for determining the similarity of a biological analyte from a model constructed from known biological fluids

    DOEpatents

    Robinson, Mark R.; Ward, Kenneth J.; Eaton, Robert P.; Haaland, David M.

    1990-01-01

    The characteristics of a biological fluid sample having an analyte are determined from a model constructed from plural known biological fluid samples. The model is a function of the concentration of materials in the known fluid samples as a function of absorption of wideband infrared energy. The wideband infrared energy is coupled to the analyte containing sample so there is differential absorption of the infrared energy as a function of the wavelength of the wideband infrared energy incident on the analyte containing sample. The differential absorption causes intensity variations of the infrared energy incident on the analyte containing sample as a function of sample wavelength of the energy, and concentration of the unknown analyte is determined from the thus-derived intensity variations of the infrared energy as a function of wavelength from the model absorption versus wavelength function.

  19. Atomic-Layer-Confined Doping for Atomic-Level Insights into Visible-Light Water Splitting.

    PubMed

    Lei, Fengcai; Zhang, Lei; Sun, Yongfu; Liang, Liang; Liu, Katong; Xu, Jiaqi; Zhang, Qun; Pan, Bicai; Luo, Yi; Xie, Yi

    2015-08-03

    A model of doping confined in atomic layers is proposed for atomic-level insights into the effect of doping on photocatalysis. Co doping confined in three atomic layers of In2S3 was implemented with a lamellar hybrid intermediate strategy. Density functional calculations reveal that the introduction of Co ions brings about several new energy levels and increased density of states at the conduction band minimum, leading to sharply increased visible-light absorption and three times higher carrier concentration. Ultrafast transient absorption spectroscopy reveals that the electron transfer time of about 1.6 ps from the valence band to newly formed localized states is due to Co doping. The 25-fold increase in average recovery lifetime is believed to be responsible for the increased of electron-hole separation. The synthesized Co-doped In2S3 (three atomic layers) yield a photocurrent of 1.17 mA cm(-2) at 1.5 V vs. RHE, nearly 10 and 17 times higher than that of the perfect In2S3 (three atomic layers) and the bulk counterpart, respectively. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Study of atomic coherence effects in multi-level V+Ξ system involving Rydberg state

    NASA Astrophysics Data System (ADS)

    Kaur, Amanjot; Singh, Neeraj; Kaur, Paramjit

    2018-06-01

    We present theoretical model to investigate the influence of hyperfine levels on the atomic coherences of V+Ξ Rydberg system. Using density matrix formulation, an analytical expression of atomic coherence for weak probe field is derived. The closely spaced hyperfine levels cause asymmetry and red shift while wavelength mismatching induced due to Rydberg state leads to reduction in magnitude and broadening of group index, absorption and dispersion profiles for moving atoms. Our system shows both Rydberg Electromagnetically induced transparency (EIT) with subluminal behavior and Rydberg Electromagnetically induced absorption (EIA) with superluminal propagation by adjusting the strengths of control and switching fields. Variation of group index with probe detuning reveals anomalous dispersion regions at Autler-Townes doublet positions. Group index for Doppler-broadened atoms at resonance condition has lower magnitude as compared to the stationary atoms and hence the group delay time of the pulse is also reduced. We also explore in-depth non-degenerate four-wave mixing (FWM) which is ignited due to the presence of three electromagnetic (e.m.) fields and concurrently, establish relationship between FWM and multi-photon atomic coherence. The transient behavior is also studied for practical realization of our considered system as optical switch.

  1. Vapor concentration monitor

    DOEpatents

    Bayly, John G.; Booth, Ronald J.

    1977-01-01

    An apparatus for monitoring the concentration of a vapor, such as heavy water, having at least one narrow bandwidth in its absorption spectrum, in a sample gas such as air. The air is drawn into a chamber in which the vapor content is measured by means of its radiation absorption spectrum. High sensitivity is obtained by modulating the wavelength at a relatively high frequency without changing its optical path, while high stability against zero drift is obtained by the low frequency interchange of the sample gas to be monitored and of a reference sample. The variable HDO background due to natural humidity is automatically corrected.

  2. The physical basis for absorption of light. [effects on wave functions of gas molecules and atoms

    NASA Technical Reports Server (NTRS)

    Pickett, H. M.

    1979-01-01

    The effects of light absorption on the wave functions of gas-phase molecules and atoms are investigated by high resolution spectral measurements of radiation emerging from a sample. A Stark-modulated sample of methyl fluoride was irradiated at the 102 GHz rotational transition and the emergent radiation was resolved by means of a spectrum analyzer. For signal oscillator frequencies below or above the molecular resonance by one modulation frequency, the amplitudes of the upper and lower modulation sidebands are found to be of nonuniform intensity, which is inconsistent with amplitude modulation. Emission due to polarization is, however, calculated to be consistent with the results observed, indicating that light absorption should be considered as a subtractive stimulated emission.

  3. Laser continuum source atomic absorption spectroscopy: Measuring the ground state with nanosecond resolution in laser-induced plasmas

    NASA Astrophysics Data System (ADS)

    Merten, Jonathan; Johnson, Bruce

    2018-01-01

    A new dual-beam atomic absorption technique is applied to laser-induced plasmas. The technique uses an optical parametric oscillator pseudocontinuum, producing emission that is both wider than the absorption line profile, but narrow enough to allow the use of an echelle spectrograph without order sorting. The dual-beam-in space implementation makes the technique immune to nonspecific attenuation of the probe beam and the structure of the pseudocontinuum. The potential for plasma diagnostics is demonstrated with spatially and temporally resolved measurements of magnesium metastable and lithium ground state optical depths in a laser-induced plasma under reduced pressure conditions. The lithium measurements further demonstrate the technique's potential for isotope ratio measurements.

  4. Plasmon excitations in doped square-lattice atomic clusters

    NASA Astrophysics Data System (ADS)

    Wang, Yaxin; Yu, Ya-Bin

    2017-12-01

    Employing the tight-binding model, we theoretically study the properties of the plasmon excitations in doped square-lattice atomic clusters. The results show that the dopant atoms would blur the absorption spectra, and give rise to extra plasmon resonant peaks as reported in the literature; however, our calculated external-field induced oscillating charge density shows that no obvious evidences indicate the so-called local mode of plasmon appearing in two-dimensional-doped atomic clusters, but the dopants may change the symmetry of the charge distribution. Furthermore, we show that the disorder of the energy level due to dopant makes the absorption spectrum has a red- or blue-shift, which depends on the position of impurities; disorder of hopping due to dopant makes a blue- or red-shift, a larger (smaller) hopping gives a blue-shift (red-shift); and a larger (smaller) host-dopant and dopant-dopant intersite coulomb repulsion induces a blue-shift (red-shift).

  5. Etalon-induced Baseline Drift And Correction In Atom Flux Sensors Based On Atomic Absorption Spectroscopy

    DOE PAGES

    Du, Yingge; Chambers, Scott A.

    2014-10-20

    Atom flux sensors based on atomic absorption (AA) spectroscopy are of significant interest in thin film growth as they can provide unobtrusive, element specific, real-time flux sensing and control. The ultimate sensitivity and performance of the sensors are strongly affected by the long-term and short term baseline drift. Here we demonstrate that an etalon effect resulting from temperature changes in optical viewport housings is a major source of signal instability which has not been previously considered or corrected by existing methods. We show that small temperature variations in the fused silica viewports can introduce intensity modulations of up to 1.5%,more » which in turn significantly deteriorate AA sensor performance. This undesirable effect can be at least partially eliminated by reducing the size of the beam and tilting the incident light beam off the viewport normal.« less

  6. The role of Gouy phase on the mechanical effects of Laguerre-Gaussian light interacting with atoms

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lembessis, V. E., E-mail: vlempesis@ksu.edu.sa; Babiker, M.; Ellinas, D.

    2016-06-10

    We consider the case of Laguerre-Gaussian (LG) light with high values of radial index, p, and/or winding number l, focussing on the effects of the Gouy phase together with other phase contributions due to the curvature in a Laguerre Gaussian beam when it interacts with atoms at near resonance. We show here that these phase anomalies amount to a significant reduction of the axial wavevector and thus lead to additional contributions to the phase gradient in the vicinity of the focus plane. In consequence, the axial recoil effects due to the stimulated emission and absorption of light by the atommore » become smaller. This has important effects on the dissipative axial forces acting on the atom, on the momentum fluctuations associated with the photon absorption and stimulated emission and on diffraction of atoms through light masks created by LG beams.« less

  7. First-principles study on silicon atom doped monolayer graphene

    NASA Astrophysics Data System (ADS)

    Rafique, Muhammad; Shuai, Yong; Hussain, Nayyar

    2018-01-01

    This paper illustrates the structural, electronic and optical properties of individual silicon (Si) atom-doped single layer graphene using density functional theory method. Si atom forms tight bonding with graphene layer. The effect of doping has been investigated by varying the concentration of Si atoms from 3.125% to 9.37% (i.e. From one to three Si atoms in 4 × 4 pure graphene supercell containing 32 carbon atoms), respectively. Electronic structure, partial density of states (PDOS) and optical properties of pure and Si atom-doped graphene sheet were calculated using VASP (Vienna ab-initio Simulation Package). The calculated results for pure graphene sheet were then compared with Si atom doped graphene. It is revealed that upon Si doping in graphene, a finite band gap appears at the high symmetric K-point, thereby making graphene a direct band gap semiconductor. Moreover, the band gap value is directly proportional to the concentration of impurity Si atoms present in graphene lattice. Upon analyzing the optical properties of Si atom-doped graphene structures, it is found that, there is significant change in the refractive index of the graphene after Si atom substitution in graphene. In addition, the overall absorption spectrum of graphene is decreased after Si atom doping. Although a significant red shift in absorption is found to occur towards visible range of radiation when Si atom is substituted in its lattice. The reflectivity of graphene improves in low energy region after Si atom substitution in graphene. These results can be useful for tuning the electronic structure and to manipulate the optical properties of graphene layer in the visible region.

  8. Thermal conductivity of rigid foam insulations for aerospace vehicles

    NASA Astrophysics Data System (ADS)

    Barrios, M.; Van Sciver, S. W.

    2013-05-01

    The present work describes measurements of the effective thermal conductivity of NCFI 24-124 foam, a spray-on foam insulation used formerly on the Space Shuttle external fuel tank. A novel apparatus to measure the effective thermal conductivity of rigid foam at temperatures ranging from 20 K to 300 K was developed and used to study three samples of NCFI 24-124 foam insulation. In preparation for measurement, the foam samples were either treated with a uniquely designed moisture absorption apparatus or different residual gases to study their impact on the effective thermal conductivity of the foam. The resulting data are compared to other measurements and mathematical models reported in the literature.

  9. Application of an atomic oxygen beam facility to the investigation of shuttle glow chemistry

    NASA Technical Reports Server (NTRS)

    Arnold, G. S.; Peplinski, D. R.

    1985-01-01

    A facility for the investigation of the interactions of energetic atomic oxygen with solids is described. The facility is comprised of a four chambered, differentially pumped molecular beam apparatus which can be equipped with one of a variety of sources of atomic oxygen. The primary source is a dc arc heated supersonic nozzle source which produces a flux of atomic oxygen in excess of 10 to the 15th power sq cm/sec at the target, at a velocity of 3.5 km/sec. Results of applications of this facility to the study of the reactions of atomic oxygen with carbon and polyimide films are briefly reviewed and compared to data obtained on various flights of the space shuttle. A brief discussion of possible application of this facility to investigation of chemical reactions which might contribute to atmosphere induced vehicle glow is presented.

  10. Remote detection of rotating machinery with a portable atomic magnetometer.

    PubMed

    Marmugi, Luca; Gori, Lorenzo; Hussain, Sarah; Deans, Cameron; Renzoni, Ferruccio

    2017-01-20

    We demonstrate remote detection of rotating machinery, using an atomic magnetometer at room temperature and in an unshielded environment. The system relies on the coupling of the AC magnetic signature of the target with the spin-polarized, precessing atomic vapor of a radio-frequency optical atomic magnetometer. The AC magnetic signatures of rotating equipment or electric motors appear as sidebands in the power spectrum of the atomic sensor, which can be tuned to avoid noisy bands that would otherwise hamper detection. A portable apparatus is implemented and experimentally tested. Proof-of-concept investigations are performed with test targets mimicking possible applications, and the operational conditions for optimum detection are determined. Our instrument provides comparable or better performance than a commercial fluxgate and allows detection of rotating machinery behind a wall. These results demonstrate the potential for ultrasensitive devices for remote industrial and usage monitoring, security, and surveillance.

  11. Two-Photon Laser-Induced Fluorescence O and N Atoms for the Study of Heterogeneous Catalysis in a Diffusion Reactor

    NASA Technical Reports Server (NTRS)

    Pallix, Joan B.; Copeland, Richard A.; Arnold, James O. (Technical Monitor)

    1995-01-01

    Advanced laser-based diagnostics have been developed to examine catalytic effects and atom/surface interactions on thermal protection materials. This study establishes the feasibility of using laser-induced fluorescence for detection of O and N atom loss in a diffusion tube to measure surface catalytic activity. The experimental apparatus is versatile in that it allows fluorescence detection to be used for measuring species selective recombination coefficients as well as diffusion tube and microwave discharge diagnostics. Many of the potential sources of error in measuring atom recombination coefficients by this method have been identified and taken into account. These include scattered light, detector saturation, sample surface cleanliness, reactor design, gas pressure and composition, and selectivity of the laser probe. Recombination coefficients and their associated errors are reported for N and O atoms on a quartz surface at room temperature.

  12. Two-photon excitation cross-section in light and intermediate atoms

    NASA Technical Reports Server (NTRS)

    Omidvar, K.

    1980-01-01

    The method of explicit summation over the intermediate states is used along with LS coupling to derive an expression for two-photon absorption cross section in light and intermediate atoms in terms of integrals over radial wave functions. Two selection rules, one exact and one approximate, are also derived. In evaluating the radial integrals, for low-lying levels, the Hartree-Fock wave functions, and for high-lying levels, hydrogenic wave functions obtained by the quantum defect method are used. A relationship between the cross section and the oscillator strengths is derived. Cross sections due to selected transitions in nitrogen, oxygen, and chlorine are given. The expression for the cross section is useful in calculating the two-photon absorption in light and intermediate atoms.

  13. Current role of ICP-MS in clinical toxicology and forensic toxicology: a metallic profile.

    PubMed

    Goullé, Jean-Pierre; Saussereau, Elodie; Mahieu, Loïc; Guerbet, Michel

    2014-08-01

    As metal/metalloid exposure is inevitable owing to its omnipresence, it may exert toxicity in humans. Recent advances in metal/metalloid analysis have been made moving from flame atomic absorption spectrometry and electrothermal atomic absorption spectrometry to the multi-elemental inductively coupled plasma (ICP) techniques as ICP atomic emission spectrometry and ICP-MS. ICP-MS has now emerged as a major technique in inorganic analytical chemistry owing to its flexibility, high sensitivity and good reproducibility. This in depth review explores the ICP-MS metallic profile in human toxicology. It is now routinely used and of great importance, in clinical toxicology and forensic toxicology to explore biological matrices, specifically whole blood, plasma, urine, hair, nail, biopsy samples and tissues.

  14. Method and apparatus for diagnosis of lead toxicity

    DOEpatents

    Rosen, John F.; Slatkin, Daniel N.; Wielopolski, Lucian

    1989-01-01

    Improved methods and apparatus for in vivo measurement of the skeletal lead burden of a patient and for diagnosis of lead toxicity are disclosed. The apparatus comprises an x-ray tube emitting soft low energy x-rays from a silver anode, a polarizer for polarizing the emitted x-rays, and a detector for detecting photons fluoresced from atoms in the patient's tibia upon irradiation by the polarized x-rays. The fluoresced photons are spectrally analyzed to determine their energy distribution. Peaks indicating the presence of lead are identified if the patient has relatively high bone lead content. The data may be compared to data recorded with respect to a similar test performed on patients having also had the conventional EDTA chelation tests performed thereon in order to correlate the test results with respect to a particular patient to the conventionally accepted EDTA chelation test.

  15. Method and apparatus for displaying information

    NASA Technical Reports Server (NTRS)

    Huang, Sui (Inventor); Eichler, Gabriel (Inventor); Ingber, Donald E. (Inventor)

    2010-01-01

    A method for displaying large amounts of information. The method includes the steps of forming a spatial layout of tiles each corresponding to a representative reference element; mapping observed elements onto the spatial layout of tiles of representative reference elements; assigning a respective value to each respective tile of the spatial layout of the representative elements; and displaying an image of the spatial layout of tiles of representative elements. Each tile includes atomic attributes of representative elements. The invention also relates to an apparatus for displaying large amounts of information. The apparatus includes a tiler forming a spatial layout of tiles, each corresponding to a representative reference element; a comparator mapping observed elements onto said spatial layout of tiles of representative reference elements; an assigner assigning a respective value to each respective tile of said spatial layout of representative reference elements; and a display displaying an image of the spatial layout of tiles of representative reference elements.

  16. Transversal Stiffness and Beta-Actin and Alpha-Actinin-4 Content of the M. Soleus Fibers in the Conditions of a 3-Day Reloading after 14-Day Gravitational Unloading

    PubMed Central

    Ogneva, I. V.

    2011-01-01

    The aim of the work was to analyze the structural changes in different parts of the sarcolemma and contractile apparatus of muscle fibers by measuring their transversal stiffness by atomic force microscopy in a three-day reloading after a 14-day gravity disuse, which was carried out by hind-limbs suspension. The object of the study was the soleus muscle of the Wistar rat. It was shown that after 14 days of disuse, there was a reduction of transversal stiffness of all points of the sarcolemma and contractile apparatus. Readaptation for 3 days leads to complete recovery of the values of the transversal stiffness of the sarcolemma and to partial value recovery of the contractile apparatus. The changes in transversal stiffness of sarcolemma correlate with beta-actin and alpha-actinin-4 in membrane protein fractions. PMID:21941432

  17. Transversal stiffness and beta-actin and alpha-actinin-4 content of the M. soleus fibers in the conditions of a 3-day reloading after 14-day gravitational unloading.

    PubMed

    Ogneva, I V

    2011-01-01

    The aim of the work was to analyze the structural changes in different parts of the sarcolemma and contractile apparatus of muscle fibers by measuring their transversal stiffness by atomic force microscopy in a three-day reloading after a 14-day gravity disuse, which was carried out by hind-limbs suspension. The object of the study was the soleus muscle of the Wistar rat. It was shown that after 14 days of disuse, there was a reduction of transversal stiffness of all points of the sarcolemma and contractile apparatus. Readaptation for 3 days leads to complete recovery of the values of the transversal stiffness of the sarcolemma and to partial value recovery of the contractile apparatus. The changes in transversal stiffness of sarcolemma correlate with beta-actin and alpha-actinin-4 in membrane protein fractions.

  18. Hands-on Force Spectroscopy: Weird Springs and Protein Folding

    ERIC Educational Resources Information Center

    Euler, Manfred

    2008-01-01

    A force spectroscopy model experiment is presented using a low-cost tensile apparatus described earlier. Force-extension measurements of twisted rubber bands are obtained. They exhibit a complex nonlinear elastic behaviour that resembles atomic force spectroscopy investigations of molecules of titin, a muscle protein. The model experiments open up…

  19. Method and apparatus for transport, introduction, atomization and excitation of emission spectrum for quantitative analysis of high temperature gas sample streams containing vapor and particulates without degradation of sample stream temperature

    DOEpatents

    Eckels, David E.; Hass, William J.

    1989-05-30

    A sample transport, sample introduction, and flame excitation system for spectrometric analysis of high temperature gas streams which eliminates degradation of the sample stream by condensation losses.

  20. Continuous wave cavity ring-down spectroscopy for velocity distribution measurements in plasma

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    McCarren, D.; Lockheed Martin, Palmdale, California 93599; Scime, E., E-mail: earl.scime@mail.wvu.edu

    2015-10-15

    We report the development of a continuous wave cavity ring-down spectroscopic (CW-CRDS) diagnostic for real-time, in situ measurement of velocity distribution functions of ions and neutral atoms in plasma. This apparatus is less complex than conventional CW-CRDS systems. We provide a detailed description of the CW-CRDS apparatus as well as measurements of argon ions and neutrals in a high-density (10{sup 9} cm{sup −3} < plasma density <10{sup 13} cm{sup −3}) plasma. The CW-CRDS measurements are validated through comparison with laser induced fluorescence measurements of the same absorbing states of the ions and neutrals.

  1. Characterization of the physico-chemical properties of polymeric materials for aerospace flight. [differential thermal and atomic absorption spectroscopic analysis of nickel cadmium batteries

    NASA Technical Reports Server (NTRS)

    Rock, M.

    1981-01-01

    Electrodes and electrolytes of nickel cadmium sealed batteries were analyzed. Different thermal analysis of negative and positive battery electrodes was conducted and the temperature ranges of occurrence of endotherms indicating decomposition of cadmium hydroxide and nickel hydroxide are identified. Atomic absorption spectroscopy was used to analyze electrodes and electrolytes for traces of nickel, cadmium, cobalt, and potassium. Calibration curves and data are given for each sample analyzed. Instrumentation and analytical procedures used for each method are described.

  2. Development of an analytical-numerical model to predict radiant emission or absorption

    NASA Technical Reports Server (NTRS)

    Wallace, Tim L.

    1994-01-01

    The development of an analytical-numerical model to predict radiant emission or absorption is discussed. A voigt profile is assumed to predict the spectral qualities of a singlet atomic transition line for atomic species of interest to the OPAD program. The present state of this model is described in each progress report required under contract. Model and code development is guided by experimental data where available. When completed, the model will be used to provide estimates of specie erosion rates from spectral data collected from rocket exhaust plumes or other sources.

  3. Optical Diagnostics in the Gaseous Electronics Conference Reference Cell

    PubMed Central

    Hebner, G. A.; Greenberg, K. E.

    1995-01-01

    A number of laser-induced fluorescence and absorption spectroscopy studies have been conducted using Gaseous Electronics Conference Reference Cells. Laser-induced fluorescence has been used to measure hydrogen atom densities, to measure argon metastable spatial profiles, to determine the sheath electric field, and to infer the electron density and temperature. Absorption spectroscopy, using lamp sources and diode lasers, has been used to measure metastable atom densities in helium and argon discharges and fluorocarbon densities in silicon etching discharges. The experimental techniques and sample results of these investigations are reviewed. PMID:29151748

  4. Estimation of calcium and magnesium in serum and urine by atomic absorption spectrophotometry

    PubMed Central

    Thin, Christian G.; Thomson, Patricia A.

    1967-01-01

    A method has been described for the estimation of calcium and magnesium in serum and urine using atomic absorption spectrophotometry. The precision and accuracy of the techniques have been determined and were found to be acceptable. The range of values for calcium and magnesium in the sera of normal adults was found to be: serum calcium (corrected to a specific gravity of 1·026) 8·38-10·08 mg. per 100 ml.; serum magnesium 1·83-2·43 mg. per 100 ml. PMID:5602562

  5. Temperature and excitation power influence on the velocity-selective optical pumping resonances of 133Cs atoms confined in an extremely thin cell

    NASA Astrophysics Data System (ADS)

    Vartanyan, T.; Polishchuk, V.; Sargsyan, A.; Krasteva, A.; Cartaleva, St.; Todorov, G.

    2018-03-01

    Linear and nonlinear absorption spectra of 133Cs vapor confined in an extremely thin cell were computed via iterations with respect to the resonance radiation intensity. When the incident radiation intensity is low, the transient polarization of the atoms that undergo frequent collisions with the cell walls leads to sub-Doppler features in the absorption spectra. Higher incident radiation intensities result in the appearance of velocity-selective optical pumping resonances. The theory developed agrees quantitatively with the experimental findings.

  6. Evaluation of methods for trace-element determination with emphasis on their usability in the clinical routine laboratory.

    PubMed

    Bolann, B J; Rahil-Khazen, R; Henriksen, H; Isrenn, R; Ulvik, R J

    2007-01-01

    Commonly used techniques for trace-element analysis in human biological material are flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry (GFAAS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Elements that form volatile hydrides, first of all mercury, are analysed by hydride generation techniques. In the absorption techniques the samples are vaporized into free, neutral atoms and illuminated by a light source that emits the atomic spectrum of the element under analysis. The absorbance gives a quantitative measure of the concentration of the element. ICP-AES and ICP-MS are multi-element techniques. In ICP-AES the atoms of the sample are excited by, for example, argon plasma at very high temperatures. The emitted light is directed to a detector, and the optical signals are processed to values for the concentrations of the elements. In ICP-MS a mass spectrometer separates and detects ions produced by the ICP, according to their mass-to-charge ratio. Dilution of biological fluids is commonly needed to reduce the effect of the matrix. Digestion using acids and microwave energy in closed vessels at elevated pressure is often used. Matrix and spectral interferences may cause problems. Precautions should be taken against trace-element contamination during collection, storage and processing of samples. For clinical problems requiring the analysis of only one or a few elements, the use of FAAS may be sufficient, unless the higher sensitivity of GFAAS is required. For screening of multiple elements, however, the ICP techniques are preferable.

  7. Containerless high temperature property measurements by atomic fluorescence

    NASA Technical Reports Server (NTRS)

    Schiffman, R. A.; Walker, C. A.

    1984-01-01

    Laser induced fluorescence (LIF) techniques for containerless study of high temperature processes and material properties was studied. Gas jet and electromagnetic levitation and electromagnetic and laser heating techniques are used with LIF in earth-based containerless high temperature experiments. Included are the development of an apparatus and its use in the studies of (1) chemical reactions on Al2O3, molybdenum, tungsten and LaB6 specimens, (2) methods for noncontact specimen temperature measurement, (3) levitation jet properties and (4) radiative lifetime and collisional energy transfer rates for electronically excited atoms.

  8. Method of trivalent chromium concentration determination by atomic spectrometry

    DOEpatents

    Reheulishvili, Aleksandre N [Tbilisi, 0183, GE; Tsibakhashvili, Neli Ya [Tbilisi, 0101, GE

    2006-12-12

    A method is disclosed for determining the concentration of trivalent chromium Cr(III) in a sample. The addition of perchloric acid has been found to increase the atomic chromium spectrometric signal due to Cr(III), while leaving the signal due to hexavalent chromium Cr(VI) unchanged. This enables determination of the Cr(III) concentration without pre-concentration or pre-separation from chromium of other valences. The Cr(III) concentration may be measured using atomic absorption spectrometry, atomic emission spectrometry or atomic fluorescence spectrometry.

  9. The Beer Lambert law measurement made easy

    NASA Astrophysics Data System (ADS)

    Onorato, Pasquale; Gratton, Luigi M.; Polesello, Marta; Salmoiraghi, Alessandro; Oss, Stefano

    2018-05-01

    We propose the use of a smartphone based apparatus as a valuable tool for investigating the optical absorption of a material and to verify the exponential decay predicted by Beer’s law. The very simple experimental activities presented here, suitable for undergraduate students, allows one to measure the material transmittance including its dependence on the incident radiation wavelength.

  10. Determination of the line shapes of atomic nitrogen resonance lines by magnetic scans

    NASA Technical Reports Server (NTRS)

    Lawrence, G. M.; Stone, E. J.; Kley, D.

    1976-01-01

    A technique is given for calibrating an atomic nitrogen resonance lamp for use in determining column densities of atoms in specific states. A discharge lamp emitting the NI multiplets at 1200 A and 1493 A is studied by obtaining absorption by atoms in a magnetic field (0-2.5 T). This magnetic scanning technique enables the determination of the absorbing atom column density, and an empirical curve of growth is obtained because the atomic f-value is known. Thus, the calibrated lamp can be used in the determination of atomic column densities.

  11. Faculty Member for Research in an Undergraduate Institution Prize Talk: Research and Teaching through high-precision spectroscopy of heavy atoms

    NASA Astrophysics Data System (ADS)

    Majumder, Tiku

    2017-04-01

    In recent decades, substantial experimental effort has centered on heavy (high-Z) atomic and molecular systems for atomic-physics-based tests of standard model physics, through (for example) measurements of atomic parity nonconservation and searches for permanent electric dipole moments. In all of this work, a crucial role is played by atomic theorists, whose accurate wave function calculations are essential in connecting experimental observables to tests of relevant fundamental physics parameters. At Williams College, with essential contributions from dozens of undergraduate students, we have pursued a series of precise atomic structure measurements in heavy metal atoms such as thallium, indium, and lead. These include measurements of hyperfine structure, transition amplitudes, and atomic polarizability. This work, involving diode lasers, heated vapor cells, and an atomic beam apparatus, has both tested the accuracy and helped guide the refinement of new atomic theory calculations. I will discuss a number of our recent experimental results, emphasizing the role played by students and the opportunities that have been afforded for research-training in this undergraduate environment. Work supported by Research Corporation, the NIST Precision Measurement Grants program, and the National Science Foundation.

  12. Turbomolecular Pumps for Holding Gases in Open Containers

    NASA Technical Reports Server (NTRS)

    Keller, John W.; Lorenz, John E.

    2010-01-01

    Proposed special-purpose turbomolecular pumps denoted turbotraps would be designed, along with mating open containers, to prevent the escape of relatively slowly (thermal) moving gas molecules from the containers while allowing atoms moving at much greater speeds to pass through. In the original intended applications, the containers would be electron-attachment cells, and the contained gases would be vapors of alkali metal atoms moving at thermal speeds that would be of the order of a fraction of 300 meters per second. These cells would be parts of apparatuses used to measure fluxes of neutral atoms incident at kinetic energies in the approximate range of 10 eV to 10 keV (corresponding to typical speeds of the order of 40,000 m/s and higher). The incident energetic neutral atoms would pass through the cells, wherein charge-exchange reactions with the alkali metal atoms would convert the neutral atoms to negative ions, which, in turn, could then be analyzed by use of conventional charged-particle optics.

  13. Scalable quantum computer architecture with coupled donor-quantum dot qubits

    DOEpatents

    Schenkel, Thomas; Lo, Cheuk Chi; Weis, Christoph; Lyon, Stephen; Tyryshkin, Alexei; Bokor, Jeffrey

    2014-08-26

    A quantum bit computing architecture includes a plurality of single spin memory donor atoms embedded in a semiconductor layer, a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, wherein a first voltage applied across at least one pair of the aligned quantum dot and donor atom controls a donor-quantum dot coupling. A method of performing quantum computing in a scalable architecture quantum computing apparatus includes arranging a pattern of single spin memory donor atoms in a semiconductor layer, forming a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, applying a first voltage across at least one aligned pair of a quantum dot and donor atom to control a donor-quantum dot coupling, and applying a second voltage between one or more quantum dots to control a Heisenberg exchange J coupling between quantum dots and to cause transport of a single spin polarized electron between quantum dots.

  14. Friction and Wear on the Atomic Scale

    NASA Astrophysics Data System (ADS)

    Gnecco, Enrico; Bennewitz, Roland; Pfeiffer, Oliver; Socoliuc, Anisoara; Meyer, Ernst

    Friction has long been the subject of research: the empirical da Vinci-Amontons friction laws have been common knowledge for centuries. Macroscopic experiments performed by the school of Bowden and Tabor revealed that macroscopic friction can be related to the collective action of small asperities. Over the last 15 years, experiments performed with the atomic force microscope have provided new insights into the physics of single asperities sliding over surfaces. This development, together with the results from complementary experiments using surface force apparatus and the quartz microbalance, have led to the new field of nanotribology. At the same time, increasing computing power has permitted the simulation of processes that occur during sliding contact involving several hundreds of atoms. It has become clear that atomic processes cannot be neglected when interpreting nanotribology experiments. Even on well-defined surfaces, experiments have revealed that atomic structure is directly linked to friction force. This chapter will describe friction force microscopy experiments that reveal, more or less directly, atomic processes during sliding contact.

  15. Doppler-free satellites of resonances of electromagnetically induced transparency and absorption on the D 2 lines of alkali metals

    NASA Astrophysics Data System (ADS)

    Sargsyan, A.; Sarkisyan, D.; Staedter, D.; Akulshin, A. M.

    2006-11-01

    The peculiarities of intra-Doppler structures that are observed in the atomic absorption spectrum of alkali metals with the help of two independent lasers have been studied. These structures accompany ultranarrow coherent resonances of electromagnetically induced transparency and absorption. With the D 2 line of rubidium taken as an example, it is shown that, in the scheme of unidirectional waves, the maximum number of satellite resonances caused by optical pumping selective with respect to the atomic velocity is equal to seven, while only six resonances are observed in the traditional scheme of saturated absorption with counterpropagating waves of the same frequency. The spectral position of the resonances and their polarity depend on the frequency of the saturating radiation, while their number and relative amplitude depend also on the experimental geometry. These features are of general character and should show themselves in the absorption spectrum on the D 2 lines of all alkali metals. An explanation of these features is given. The calculated spectral separations between the resonances are compared to the experimental ones, and their possible application is discussed.

  16. The Star-grazing Bodies in the HD 172555 System

    NASA Astrophysics Data System (ADS)

    Grady, C. A.; Brown, Alexander; Welsh, Barry; Roberge, Aki; Kamp, Inga; Rivière Marichalar, P.

    2018-06-01

    Kiefer et al. reported the detection of infalling Ca II absorption in HD 172555, a member of the β Pictoris Moving Group (βPMG). We obtained HST Space Telescope Imaging Spectrograph and Cosmic Origins Spectrograph spectroscopy of this star at 2 epochs separated by a week, and we report the discovery of infalling gas in resonant transitions of Si III and IV, C II and IV, and neutral atomic oxygen. Variable absorption is seen in the C II transitions and is optically thick, with covering factors which range between 58% and 68%, similar to features seen in β Pictoris. The O I spectral profile resembles that of C II, showing a strong low-velocity absorption to +50 km s‑1 in the single spectral segment obtained during orbital night, as well as what may be higher-velocity absorption. Studies of the mid-IR spectrum of this system have suggested the presence of silica. The O I absorption differs from that seen in Si III, suggesting that the neutral atomic oxygen does not originate in SiO dissociation products but in a more volatile parent molecule such as CO.

  17. Uniform Fe3O4 coating on flower-like ZnO nanostructures by atomic layer deposition for electromagnetic wave absorption.

    PubMed

    Wan, Gengping; Wang, Guizhen; Huang, Xianqin; Zhao, Haonan; Li, Xinyue; Wang, Kan; Yu, Lei; Peng, Xiange; Qin, Yong

    2015-11-21

    An elegant atomic layer deposition (ALD) method has been employed for controllable preparation of a uniform Fe3O4-coated ZnO (ZnO@Fe3O4) core-shell flower-like nanostructure. The Fe3O4 coating thickness of the ZnO@Fe3O4 nanostructure can be tuned by varying the cycle number of ALD Fe2O3. When serving as additives for microwave absorption, the ZnO@Fe3O4-paraffin composites exhibit a higher absorption capacity than the ZnO-paraffin composites. For ZnO@500-Fe3O4, the effective absorption bandwidth below -10 dB can reach 5.2 GHz and the RL values below -20 dB also cover a wide frequency range of 11.6-14.2 GHz when the coating thickness is 2.3 mm, suggesting its potential application in the treatment of the electromagnetic pollution problem. On the basis of experimental observations, a mechanism has been proposed to understand the enhanced microwave absorption properties of the ZnO@Fe3O4 composites.

  18. Hydrogen storage materials discovery via high throughput ball milling and gas sorption.

    PubMed

    Li, Bin; Kaye, Steven S; Riley, Conor; Greenberg, Doron; Galang, Daniel; Bailey, Mark S

    2012-06-11

    The lack of a high capacity hydrogen storage material is a major barrier to the implementation of the hydrogen economy. To accelerate discovery of such materials, we have developed a high-throughput workflow for screening of hydrogen storage materials in which candidate materials are synthesized and characterized via highly parallel ball mills and volumetric gas sorption instruments, respectively. The workflow was used to identify mixed imides with significantly enhanced absorption rates relative to Li2Mg(NH)2. The most promising material, 2LiNH2:MgH2 + 5 atom % LiBH4 + 0.5 atom % La, exhibits the best balance of absorption rate, capacity, and cycle-life, absorbing >4 wt % H2 in 1 h at 120 °C after 11 absorption-desorption cycles.

  19. The determination of vanadium in brines by atomic absorption spectroscopy

    USGS Publications Warehouse

    Crump-Wiesner, Hans J.; Feltz, H.R.; Purdy, W.C.

    1971-01-01

    A standard addition method is described for the determination of vanadium in brines by atomic absorption spectroscopy with a nitrous oxide-acetylene flame. Sample pH is adjusted to 1.0 with concentrated hydrochloric acid and the vanadium is directly extracted with 5% cupferron in methyl isobutyl ketone (MIBK). The ketone layer is then aspirated into the flame and the recorded absorption values are plotted as a function of the concentration of the added metal. As little as 2.5 ??g l-1 of vanadium can be detected under the conditions of the procedure. Tungsten and tin interfere when present in excess of 5 and 10 ??g ml-1, respectively. The concentrations of the two interfering ions normally found in brines are well below interference levels. ?? 1971.

  20. Application of thermospray flame furnace atomic absorption spectrometry for investigation of silver nanoparticles.

    PubMed

    Sirirat, Natnicha; Tetbuntad, Kornrawee; Siripinyanond, Atitaya

    2017-03-01

    Thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) was applied to investigate the time-dependent absorption peak profile of various forms of silver. The thermospray flame furnace was set up with a 10-cm-long nickel tube with six holes, each 2.0 mm in diameter, to allow the flame to enter, and this nickel tube acted as a furnace. A sample of 300 μL was introduced into this furnace by use of water as a carrier at a flow rate of 0.5 mL min -1 through the ceramic capillary (0.5-mm inner diameter and 2.0-mm outer diameter), which was inserted into the front hole of the nickel tube. The system was applied to examine atomization behaviors of silver nanoparticles (AgNPs) with particle sizes ranging from 10 to 100 nm. The atomization rate of AgNPs was faster than that of the dissolved silver ion. With increased amount of silver, the decay time observed from the time-dependent absorption peak profile was shortened in the case of dissolved silver ion, but it was increased in the case of AgNPs. With the particle size ranging from 10 to 100 nm, the detection sensitivity was indirectly proportional to the particle size, suggesting that TS-FF-AAS may offer insights into the particle size of AgNPs provided that the concentration of the silver is known. To obtain quantitative information on AgNPs, acid dissolution of the particles was performed before TS-FF-AAS analysis, and recoveries of 80-110% were obtained.

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