WorldWideScience

Sample records for two-line atomic fluorescence

  1. Development of temperature imaging using two-line atomic fluorescence.

    Science.gov (United States)

    Medwell, Paul R; Chan, Qing N; Kalt, Peter A M; Alwahabi, Zeyad T; Dally, Bassam B; Nathan, Graham J

    2009-02-20

    This work aims to advance understanding of the coupling between temperature and soot. The ability to image temperature using the two-line atomic fluorescence (TLAF) technique is demonstrated. Previous TLAF theory is extended from linear excitation into the nonlinear fluence regime. Nonlinear regime two-line atomic fluorescence (NTLAF) provides superior signal and reduces single-shot uncertainty from 250 K for conventional TLAF down to 100 K. NTLAF is shown to resolve the temperature profile across the stoichiometric envelope for hydrogen, ethylene, and natural gas flames, with deviation from thermocouple measurements not exceeding 100 K, and typically ≲30 K. Measurements in flames containing soot demonstrate good capacity of NTLAF to exclude interferences that hamper most two-dimensional thermometry techniques.

  2. Potential of two-line atomic fluorescence for temperature imaging in turbulent indium-oxide-producing flames

    Energy Technology Data Exchange (ETDEWEB)

    Münsterjohann, Bettina; Huber, Franz J. T.; Klima, Tobias C.; Holfelder, Sandra; Engel, Sascha R. [Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Lehrstuhl für Technische Thermodynamik (LTT) (Germany); Miller, Joseph D. [Aerospace Systems Directorate, Air Force Research Laboratory (United States); Meyer, Terrence R. [Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen Graduate School in Advanced Optical Technologies (SAOT) (Germany); Will, Stefan, E-mail: stefan.will@fau.de [Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Lehrstuhl für Technische Thermodynamik (LTT) (Germany)

    2015-11-15

    The applicability of two-line atomic fluorescence (TLAF) for temperature imaging in an indium-based flame spray pyrolysis (FSP) process is demonstrated using a single tunable optical parametric oscillator (OPO) to generate the required excitation wavelengths consecutively. Single-shot images of the detected fluorescence signals demonstrate that the signal levels in the flame are suitable for evaluation of temperature and verify the capability and potential of the measurement technique directly during particle formation without additional indium seeding. Qualitative averaged two-dimensional temperature distributions in the FSP flame are presented, showing the influence of varying sheath gas flow rates on the resulting temperature distribution. With the addition of a second OPO and detection system, the two fluorescence signals acquired consecutively in this work could be obtained simultaneously and enable spatio-temporally resolved single-shot temperature measurements in flame synthesis processes of indium-containing nanoparticles.

  3. Imaging an atomic beam using fluorescence

    Institute of Scientific and Technical Information of China (English)

    Ming He(何明); Jin Wang(王谨); Mingsheng Zhan(詹明生)

    2003-01-01

    A fluorescence detection scheme is applied to image an atomic beam. Using two laser diodes as the sources of detection light and pumping light respectively, the fluorescence image of the atomic beam is then observed by a commercial CCD-camera, which is corresponding to the atomic state and velocity distribution. The detection scheme has a great utilization in the experiments of cold atoms and atomic optics.

  4. Containerless Atomic-Fluorescence Property Measurements

    Science.gov (United States)

    Nordine, P.; Schiffman, R.; Walker, C.

    1987-01-01

    Report describes studies conducted to establish and verify use of laser-induced fluorescence in monitoring and controlling high-temperature containerless processes. Specimens levitated by gas jets or electromagnetic fields and heated by laser beams or electromagnetic induction while being irradiated and detected by fluorescence technique. Makes quantitative and qualitative comparisons among three new methods of temperature measurement; all rely on laser-induced fluorescence. One method gas-density thermometry with seed gas. Other two methods involve measurements of velocities of evaporating atoms or of population ratios of different electronic states.

  5. Atomic fluorescence study of high temperature aerodynamic levitation

    Science.gov (United States)

    Nordine, P. C.; Schiffman, R. A.; Sethi, D. S.

    1982-01-01

    Ultraviolet laser induced atomic fluorescence has been used to characterize supersonic jet aerodynamic levitation experiments. The levitated specimen was a 0.4 cm sapphire sphere that was separately heated at temperatures up to 2327 K by an infrared laser. The supersonic jet expansion and thermal gradients in the specimen wake were studied by measuring spatial variations in the concentration of atomic Hg added to the levitating argon gas stream. Further applications of atomic fluorescence in containerless experiments, such as ideal gas fluorescence thermometry and containerless process control are discussed.

  6. Resonance Fluorescence from an Artificial Atom in Squeezed Vacuum

    National Research Council Canada - National Science Library

    Toyli, D. M; Eddins, A. W; Boutin, S; Puri, S; Hover, D; Bolkhovsky, V; Oliver, W. D; Blais, A; Siddiqi, I

    2016-01-01

    .... We strongly couple microwave-frequency squeezed light to a superconducting artificial atom and detect the resulting fluorescence with high resolution enabled by a broadband traveling-wave parametric amplifier...

  7. Containerless high temperature property measurements by atomic fluorescence

    Science.gov (United States)

    Nordine, P. C.; Schiffman, R. A.

    1982-01-01

    Laser induced fluorescence techniques were developed for the containerless study of high temperature processes, material properties, levitation, and heating techniques for containerless earth-based experimentation. Experiments were performed in which fluorescence of atomic aluminum, mercury, or tungsten were studied. These experiments include measurements of: (1) Al atom evaporation from CW CO2 laser heated and aerodynamically levitated sapphire and alumina spheres, and self-supported sapphire filaments, (2) Al atom reaction with ambient oxygen in the wake of a levitated specimen, (3) Hg atom concentrations in the wake of levitated alumina and sapphire spheres, relative to the ambient Hg atom concentration, (4) Hg atom concentrations in supersonic levitation jets, and (5) metastable, electronically excited W atom concentrations produced by evaporation of an electrically heated tungsten filament.

  8. Theory of analytical curves in atomic fluorescence flame spectrometry

    NARCIS (Netherlands)

    Hooymayers, H.P.

    1968-01-01

    An explicit expression for the intensity of atomic resonance fluorescence as a function of atomic concentration in a flame is derived under certain idealized conditions. The expression is generally valid for a pure Doppler absorption line profile as well as for a combined Doppler and collisional bro

  9. Resonance Fluorescence from an Artificial Atom in Squeezed Vacuum

    Directory of Open Access Journals (Sweden)

    D. M. Toyli

    2016-07-01

    Full Text Available We present an experimental realization of resonance fluorescence in squeezed vacuum. We strongly couple microwave-frequency squeezed light to a superconducting artificial atom and detect the resulting fluorescence with high resolution enabled by a broadband traveling-wave parametric amplifier. We investigate the fluorescence spectra in the weak and strong driving regimes, observing up to 3.1 dB of reduction of the fluorescence linewidth below the ordinary vacuum level and a dramatic dependence of the Mollow triplet spectrum on the relative phase of the driving and squeezed vacuum fields. Our results are in excellent agreement with predictions for spectra produced by a two-level atom in squeezed vacuum [Phys. Rev. Lett. 58, 2539 (1987], demonstrating that resonance fluorescence offers a resource-efficient means to characterize squeezing in cryogenic environments.

  10. Study on Atomic Fluorescence Spectrometry Excited by Synchrotron Radiation

    Institute of Scientific and Technical Information of China (English)

    Jia-jia Guo; Wu-er Gan; Guo-bin Zhang; Qing-de Su

    2008-01-01

    A novel analysis approach using atomic fluorescence excited by synchrotron radiation is presented. A system for synchrotron radiation-atomic fluorescence spectrometry is developed, and experimental conditions such as flow rate, analyte acidity, concentration of pre-reducing and hydrogenation system are optimized. The proposed method is successfully applied to get an excitation spectrum of arsenic. Seven of ten primary spectral lines, four of which have never been reported by means of atomic fluorescence spectrometry, agree well with the existing reports. The other three are proposed for the first time. Excitation potentials and possible transitions are investigated. Especially for the prominent line at 234.99 nm, the mechanism of generation is discussed and a model of energy transition processes is proposed.

  11. Driving the atom by atomic fluorescence: Analytic results for the power and noise spectra

    OpenAIRE

    2000-01-01

    We study how the spectral properties of resonance fluorescence propagate through a two-atom system. Within the weak-driving-field approximation we find that, as we go from one atom to the next, the power spectrum exhibits both subnatural linewidth narrowing and large asymmetries while the noise spectrum of the squeezed quadrature narrows but remains otherwise unchanged. Analytical results for the observed spectral features of the fluorescence are provided and their origin is thoroughly discus...

  12. Characterizing optical dipole trap via fluorescence of trapped cesium atoms

    Institute of Scientific and Technical Information of China (English)

    LIU Tao; GENG Tao; YAN Shubin; LI Gang; ZHANG Jing; WANG Junmin; PENG Kunchi; ZHANG Tiancai

    2006-01-01

    Optical dipole trap (ODT) is becoming an important tool of manipulating neutral atoms. In this paper ODT is realized with a far-off resonant laser beam strongly focused in the magneto-optical trap (MOT) of cesium atoms. The light shift is measured by simply monitoring the fluorescence of the atoms in the magneto-optical trap and the optical dipole trap simultaneously. The advantages of our experimental scheme are discussed, and the effect of the beam waist and power on the potential of dipole trap as well as heating rate is analyzed.

  13. Flame-in-gas-shield and miniature diffusion flame hydride atomizers for atomic fluorescence spectrometry: optimization and comparison

    OpenAIRE

    Marschner, K; Musil, S. (Stanislav); Dědina, J. (Jiří)

    2015-01-01

    A detailed optimization of relevant experimental parameters of two hydride atomizers for atomic fluorescence spectrometry: flame-in-gas-shield atomizer with a two-channel shielding unit and a standard atomizer for atomic fluorescence spectrometry, miniature diffusion flame, was performed. Arsine, generated by the reaction with NaBH4 in a flow injection arrangement, was chosen as the model hydride. Analytical characteristics of both the atomizers (sensitivity, noise, limits of detection) were ...

  14. Ultimate statistical physics: fluorescence of a single atom

    Science.gov (United States)

    Pomeau, Yves; Le Berre, Martine; Ginibre, Jean

    2016-10-01

    We discuss the statistics of emission of photons by a single atom or ion illuminated by a laser beam at the frequency of quasi-resonance between two energy levels, a situation that corresponds to real experiments. We extend this to the case of two laser beams resonant with the energy differences between two excited levels and the ground state (three level atom in V-configuration). We use a novel approach to this type of problem by considering a Kolmogorov equation for the probability distribution of the atomic state, which takes into account first the deterministic evolution of this state under the effect of the incoming laser beam and second the random emission of photons during the spontaneous decay of the excited state(s) to the ground state. This approach yields solvable equations in the two level atom case. For the three level atom case we set the problem and clearly define its frame. The results obtained are valid in both opposite limits of rare and frequent spontaneous decay, compared to the period of the optical Rabi oscillations due to the interaction between resonant excitation and atomic levels. Our analysis gives access to various statistical properties of the fluorescence light, including one showing that its fluctuations in time are not invariants under time reversal. This result makes evident the fundamentally irreversible character of quantum measurements, represented here by the emission of photons of fluorescence.

  15. Resonance fluorescence of a trapped three-level atom

    CERN Document Server

    Bienert, M; Morigi, G; Bienert, Marc; Merkel, Wolfgang; Morigi, Giovanna

    2003-01-01

    We investigate theoretically the spectrum of resonance fluorescence of a harmonically trapped atom, whose internal transitions are $\\Lambda$--shaped and driven at two-photon resonance by a pair of lasers, which cool the center--of--mass motion. For this configuration, photons are scattered only due to the mechanical effects of the quantum interaction between light and atom. We study the spectrum of emission in the final stage of laser--cooling, when the atomic center-of-mass dynamics is quantum mechanical and the size of the wave packet is much smaller than the laser wavelength (Lamb--Dicke limit). We use the spectral decomposition of the Liouville operator of the master equation for the atomic density matrix and apply second order perturbation theory. We find that the spectrum of resonance fluorescence is composed by two narrow sidebands -- the Stokes and anti-Stokes components of the scattered light -- while all other signals are in general orders of magnitude smaller. For very low temperatures, however, th...

  16. Fluorescence Quenching of Benzaldehyde in Water by Hydrogen Atom Abstraction.

    Science.gov (United States)

    Fletcher, Katharyn; Bunz, Uwe H F; Dreuw, Andreas

    2016-09-01

    We computed the mechanism of fluorescence quenching of benzaldehyde in water through relaxed potential energy surface scans. Time-dependent density functional theory calculations along the protonation coordinate from water to benzaldehyde reveal that photoexcitation to the bright ππ* (S3 ) state is immediately followed by ultrafast decay to the nπ* (S1 ) state. Evolving along this state, benzaldehyde (BA) abstracts a hydrogen atom, resulting in a BAH(.) and OH(.) radical pair. Benzaldehyde does not act as photobase in water, but abstracts a hydrogen atom from a nearby solvent molecule. The system finally decays back to the ground state by non-radiative decay and an electron transfers back to the OH(.) radical. Proton transfer from BAH(+) to OH(-) restores the initial situation, BA in water.

  17. Single-atom-resolved fluorescence imaging of an atomic Mott insulator

    DEFF Research Database (Denmark)

    Sherson, Jacob; Weitenberg, Christof; Andres, Manuel

    2010-01-01

    in situ images of a quantum fluid in which each underlying quantum particle is detected. Here we report fluorescence imaging of strongly interacting bosonic Mott insulators in an optical lattice with single-atom and single-site resolution. From our images, we fully reconstruct the atom distribution......The reliable detection of single quantum particles has revolutionized the field of quantum optics and quantum information processing. For several years, researchers have aspired to extend such detection possibilities to larger-scale, strongly correlated quantum systems 1 , 2 in order to record...

  18. Development of a 2D temperature measurement technique for combustion diagnostics using 2-line atomic fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Engstroem, Johan

    2001-01-01

    The present thesis is concerned with the development and application of a novel planar laser-induced fluorescence (PLIF) technique for temperature measurements in a variety of combusting flows. Accurate measurement of temperature is an essential task in combustion diagnostics, since temperature is one of the most fundamental quantities for the characterization of combustion processes. The technique is based on two-line atomic fluorescence (TLAF) from small quantities of atomic indium (In) seeded into the fuel. It has been developed from small-scale experiments in laboratory flames to the point where practical combustion systems can be studied. The technique is conceptually simple and reveals temperature information in the post-flame regions. The viability of the technique has been tested in three extreme measurement situations: in spark ignition engine combustion, in ultra-lean combustion situations such as lean burning aero-engine concepts and, finally, in fuel-rich combustion. TLAF was successfully applied in an optical Sl engine using isooctane as fuel. The wide temperature sensitivity, 700 - 3000 K, of the technique using indium atoms allowed measurements over the entire combustion cycle in the engine to be performed. In applications in lean combustion a potential problem caused by the strong oxidation processes of indium atoms was encountered. This limits measurement times due to deposits of absorbing indium oxide on measurement windows. The seeding requirement is a disadvantage of the technique and can be a limitation in some applications. The results from experiments performed in sooting flames are very promising for thermometry measurements in such environments. Absorption by hydrocarbons and other native species was found to be negligible. Since low laser energies and low seeding concentrations could be used, the technique did not, unlike most other incoherent optical thermometry techniques, suffer interferences from LII of soot particles or LIF from PAH

  19. Flame-in-gas-shield and miniature diffusion flame hydride atomizers for atomic fluorescence spectrometry: optimization and comparison

    Energy Technology Data Exchange (ETDEWEB)

    Marschner, Karel, E-mail: karel.marschner@biomed.cas.cz [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic); Charles University in Prague, Faculty of Science, Department of Analytical Chemistry, Albertov 8, 128 43 Prague (Czech Republic); Musil, Stanislav; Dědina, Jiří [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic)

    2015-07-01

    A detailed optimization of relevant experimental parameters of two hydride atomizers for atomic fluorescence spectrometry: flame-in-gas-shield atomizer with a two-channel shielding unit and a standard atomizer for atomic fluorescence spectrometry, miniature diffusion flame, was performed. Arsine, generated by the reaction with NaBH{sub 4} in a flow injection arrangement, was chosen as the model hydride. Analytical characteristics of both the atomizers (sensitivity, noise, limits of detection) were compared. Under optimum conditions sensitivity obtained with flame-in-gas-shield atomizer was approximately twice higher than with miniature diffusion flame. The additional advantage of flame-in-gas-shield atomizer is significantly lower flame emission resulting in a better signal to noise ratio. The resulting arsenic limits of detection for miniature diffusion flame and flame-in-gas-shield atomizer were 3.8 ng l{sup −1} and 1.0 ng l{sup −1}, respectively. - Highlights: • We optimized and compared two hydride atomizers for atomic fluorescence spectrometry. • Miniature diffusion flame and flame-in-gas-shield atomizer were optimized. • The limit of detection for arsenic was 1.0 ng l{sup −1}.

  20. Influence of angle's ranges for recording an X-ray fluorescence hologram on reconstructed atomic images

    Institute of Scientific and Technical Information of China (English)

    XIE Hong-Lan; CHEN Jian-Wen; GAO Hong-Yi; ZHU Hua-Feng; LI Ru-Xin; XU Zhi-Zhan

    2004-01-01

    X-ray fluorescence holography (XFH) is a novel method for three-dimensional (3D) imaging of atomic structure. Theoretically, in an XFH experiment, one has to measure the fluorescence energy on a spherical surface to get well-resolved 3D images of atoms. But in practice, the experimental system arrangement does not allow the measurement of the fluorescent intensity oscillations in the full sphere. The holographic information losses because of the limited sampling range (less than 4π) will directly result in defective reconstructed atomic images. In this work, the atomic image of a Fe single crystal (001) was reconstructed by numerically simulating X-ray fluorescence holograms of the crystal at different recording angle's ranges and step lengths. Influences of the ranges of azimuth angles and polar angles and the step length of polar angles on the reconstructed atomic images were discussed.

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

    Science.gov (United States)

    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.

  2. Double-well atom trap for fluorescence detection at the Heisenberg limit

    Science.gov (United States)

    Stroescu, Ion; Hume, David B.; Oberthaler, Markus K.

    2015-01-01

    We experimentally demonstrate an atom number detector capable of simultaneous detection of two mesoscopic ensembles with single-atom resolution. Such a sensitivity is a prerequisite for quantum metrology at a precision approaching the Heisenberg limit. Our system is based on fluorescence detection of atoms in a hybrid trap in which a dipole barrier divides a magneto-optical trap into two separated wells. We introduce a noise model describing the various sources contributing to the measurement error and report a limit of up to 500 atoms for single-atom resolution in the atom number difference.

  3. Saturation of Energy Levels in Analytical Atomic Fluorescence Spectrometry. II. Experimental.

    Science.gov (United States)

    1981-01-30

    RESEARCH Contract N14-76-C-0838 Task Ao. NR 051-622 TECHNICAL REPORT NO. 34 SATURATION OF ENERGY LEVELS IN ANALYTICAL ATOMIC FLUORESCENCE SPECTROMETRY II...an assumption which is valid only if the daral o’l of 111, cxcilIatio n pulse is mucl ) longer than the fluorescence life- time of the tjaii!,ition

  4. A double-well atom trap for fluorescence detection at the Heisenberg limit

    CERN Document Server

    Stroescu, Ion; Oberthaler, Markus K

    2014-01-01

    We experimentally demonstrate an atom number detector capable of simultaneous detection of two mesoscopic ensembles with single atom resolution. Such a sensitivity is a prerequisite for going beyond quantum metrology with spin-squeezed states. Our system is based on fluorescence detection of atoms in a novel hybrid trap in which a dipole barrier divides a magneto-optical trap into two separated wells. We introduce a noise model describing the various sources contributing to the measurement error and report a limit of up to 500 atoms for the exact determination of the atom number difference.

  5. Resonance fluorescence of a cold atom in a high-finesse resonator

    CERN Document Server

    Bienert, M; Torres, J M; Zippilli, S; Bienert, Marc; Morigi, Giovanna; Zippilli, Stefano

    2007-01-01

    We study the spectra of emission of a system composed by an atom, tightly confined inside a high-finesse resonator, when the atom is driven by a laser and is at steady state of the cooling dynamics induced by laser and cavity field. In general, the spectrum of resonance fluorescence and the spectrum at the cavity output contain complementary information about the dynamics undergone by the system. In certain parameter regimes, quantum interference effects between the scattering processes induced by cavity and laser field lead to the selective suppression of features of the resonance fluorescence spectrum, which are otherwise visible in the spectrum of laser-cooled atoms in free space.

  6. Cooperative fluorescence from a strongly driven dilute cloud of atoms

    DEFF Research Database (Denmark)

    Ott, Johan Raunkjær; Wubs, Martijn; Lodahl, Peter;

    2013-01-01

    We investigate cooperative fluorescence in a dilute cloud of strongly driven two-level emitters. Starting from the Heisenberg equations of motion, we compute the first-order scattering corrections to the saturation of the excited-state population and to the resonance-fluorescence spectrum, which...... both require going beyond the state-of-the-art linear-optics approach to describe collective phenomena. A dipole blockade is observed due to long-range dipole-dipole coupling that vanishes at stronger driving fields. Furthermore, we compute the inelastic component of the light scattered by a cloud...

  7. Ultimate Statistical Physics: fluorescence of a single atom

    CERN Document Server

    Pomeau, Yves; Ginibre, Jean

    2016-01-01

    We discuss the statistics of emission of photons by a single atom or ion illuminated by a laser beam at the frequency of quasi-resonance between two energy levels, a situation that corresponds to real experiments. We extend this to the case of two laser beams resonant with the energy differences between two excited levels and the ground state (three level atom in V-configuration). We use a novel approach of this type of problem by considering Kolmogorov equation for the probability distribution of the atomic state which takes into account first the deterministic evolution of this state under the effect of the incoming laser beam and the random emission of photons during the spontaneous decay of the excited state(s) to the ground state. This approach yields solvable equations in the two level atom case. For the three level atom case we set the problem and define clearly its frame. The results obtained are valid both in the opposite limits of rare and of frequent spontaneous decay, compared to the period of the...

  8. In-trap fluorescence detection of atoms in a microscopic dipole trap

    CERN Document Server

    Hilliard, A J; Sompet, P; Carpentier, A V; Andersen, M F

    2015-01-01

    We investigate fluorescence detection using a standing wave of blue-detuned light of one or more atoms held in a deep, microscopic dipole trap. The blue-detuned standing wave realizes a Sisyphus laser cooling mechanism so that an atom can scatter many photons while remaining trapped. When imaging more than one atom, the blue detuning limits loss due to inelastic light-assisted collisions. Using this standing wave probe beam, we demonstrate that we can count from one to the order of 100 atoms in the microtrap with sub-poissonian precision.

  9. Atomic force fluorescence microscopy : combining the best of two worlds

    NARCIS (Netherlands)

    Kassies, Roelf

    2005-01-01

    The complementary strengths and weaknesses of AFM and optical microscopy leads to the desire to integrate both techniques into a single microscope. This thesis describes the development of a com-bined AFM / confocal °uorescence microscope. This atomic force °uorescence microscope (AFFM) combines hig

  10. Two-step laser excited atomic fluorescence spectrometry determination of mercury

    Science.gov (United States)

    Resto, W.; Badini, R. G.; Smith, B. W.; Stevenson, C. L.; Winefordner, J. D.

    1993-04-01

    A novel method for the determination of mercury by laser excited atomic fluorescence with electrothermal atomization (LEAFS-ETA) has been developed. The experimental set-up consisted of a dual dye-laser system pumped with a XeCl excimer laser operated at 10 Hz, and an electrothermal atomizer with platform atomization. The atomization program allowed time for the injection of Pd (as a matrix modifier) and used a drying step at 110°C and an atomization step at 1200°C. The collection is made at 90° using a pierced mirror, an achromat lens and a long-pass filter. The monochromator is fitted with a 1P28 PMT. The signal is processed by using a boxcar and an analog to digital interface. The excitation scheme is a two-step process, with λ 1 = 253.7 nm and λ 2 = 435.8 nm. Direct fluorescence is observed at 546.1 nm. The limit of detection (LOD) obtained is 90 fg (9 pptr with 10 μ1 injection). The linear dynamic range (LDR) is five orders of magnitude and is limited by the non-linearity of the co-operative processes occurring at higher concentrations. In order to extend the LDR to higher amounts of mercury, indirect fluorescence is collected with the less sensitive line at 407.8 nm, allowing concentrations of 1 ppm and up to be measured, extending the LDR of the technique to at least seven orders of magnitude.

  11. Polymerized LB Films Imaged with a Combined Atomic Force Microscope-Fluorescence Microscope

    NARCIS (Netherlands)

    Putman, C.A.J.; Putman, Constant A.J.; Hansma, Helen G.; Gaub, Hermann E.; Hansma, Paul K.

    1992-01-01

    The first results obtained with a new stand-alone atomic force microscope (AFM) integrated with a standard Zeiss optical fluorescence microscope are presented. The optical microscope allows location and selection of objects to be imaged with the high-resolution AFM. Furthermore, the combined

  12. Polymerized LB films imaged with a combined atomic force microscope-fluorescence microscope

    NARCIS (Netherlands)

    Putman, Constant A.J.; Hansma, Helen G.; Gaub, Hermann E.; Hansma, Paul K.

    1992-01-01

    The first results obtained with a new stand-alone atomic force microscope (AFM) integrated with a standard Zeiss optical fluorescence microscope are presented. The optical microscope allows location and selection of objects to be imaged with the high-resolution AFM. Furthermore, the combined microsc

  13. Observation of DNA Molecules Using Fluorescence Microscopy and Atomic Force Microscopy

    Science.gov (United States)

    Ito, Takashi

    2008-01-01

    This article describes experiments for an undergraduate instrumental analysis laboratory that aim to observe individual double-stranded DNA (dsDNA) molecules using fluorescence microscopy and atomic force microscopy (AFM). dsDNA molecules are observed under several different conditions to discuss their chemical and physical properties. In…

  14. Observation of DNA Molecules Using Fluorescence Microscopy and Atomic Force Microscopy

    Science.gov (United States)

    Ito, Takashi

    2008-01-01

    This article describes experiments for an undergraduate instrumental analysis laboratory that aim to observe individual double-stranded DNA (dsDNA) molecules using fluorescence microscopy and atomic force microscopy (AFM). dsDNA molecules are observed under several different conditions to discuss their chemical and physical properties. In…

  15. Far-field resonance fluorescence from a dipole-interacting laser-driven cold atomic gas

    Science.gov (United States)

    Jones, Ryan; Saint, Reece; Olmos, Beatriz

    2017-01-01

    We analyze the temporal response of the fluorescence light that is emitted from a dense gas of cold atoms driven by a laser. When the average interatomic distance is comparable to the wavelength of the photons scattered by the atoms, the system exhibits strong dipolar interactions and collective dissipation. We solve the exact dynamics of small systems with different geometries and show how these collective features are manifest in the scattered light properties such as the photon emission rate, the power spectrum and the second-order correlation function. By calculating these quantities beyond the weak (linear) driving limit, we make progress in understanding the signatures of collective behavior in these many-body systems. Furthermore, we shed light on the role of disorder and averaging on the resonance fluorescence, of direct relevance for recent experimental efforts that aim at the exploration of many-body effects in dipole-dipole interacting gases of atoms.

  16. [Investigation of enhancing effect for hydride generation-atomic fluorescence of transition metal elements].

    Science.gov (United States)

    Sun, Han-Wen; Suo, Ran

    2008-11-01

    A mechanism of hydride generation based on disassembly reaction of hydrogen-transferred interim state [M(BH4)m]* was developed by investigating the effect of reaction medium acidity on hydride generation. The effects of Co2+ and Ni2+, phenanthroline and 8-hydroxyquinoline on hydride generation-atomic fluorescence signals of Zn, Cd, Cu and Ni were studied, respectively, and their enhancing mechnism was discussed. The enhancing effect Co2+ and Ni2+ on the fluorescence signals of Zn and Cd was due to the increase in transmission efficiency of hydride of Zn and Cd. There was a synergic enhancing effect between phenanthroline or 8-hydroxyquinoline and Co2+ on the fluorescence signals of Zn and Cd, however no synergic enhancing effect between phenanthroline and 8-hydroxyquinoline on the fluorescence signals of Zn and Cd. The simulative action of cationic surfactant, anion surfactant and non-ionic surfactant surfactant to hydride generation was investigated. It is shown that both cationic surfactant and non-ionic surfactant have obvious enhancing effect on the fluorescence signals of analytes because of the decrease in surface tension of reaction solution. The release characteristics of hydride from the absorption solution containing surfactant was ulteriorly examined by using graphite furnace atomic absorption spectrometry, and the mechanism of enhancing effect of surfactant on hydride generation and transmission was proposed.

  17. Fluorescence spectra of atomic ensembles in a magneto-optical trap as an optical lattice

    CERN Document Server

    Yoon, Seokchan; Kang, Sungsam; Kim, Wook-Rae; Kim, Jung-Ryul; An, Kyungwon

    2015-01-01

    We present a study on characteristics of a magneto-optical trap (MOT) as an optical lattice. Fluorescence spectra of atoms trapped in a MOT with a passively phase-stabilized beam configuration have been measured by means of the photon-counting heterodyne spectroscopy. We observe a narrow Rayleigh peak and well-resolved Raman sidebands in the fluorescence spectra which clearly show that the MOT itself behaves as a three-dimensional optical lattice. Optical-lattice-like properties of the phase-stabilized MOT such as vibrational frequencies and lineshapes of Rayleigh peak and Raman sidebands are investigated systematically for various trap conditions.

  18. Phase Dependence of Fluorescence Spectrum of a Two-Level Atom in a Trichromatic Field

    Institute of Scientific and Technical Information of China (English)

    LI Jing-Yan; HU Xiang-Ming; LI Xiao-Xia; SHI Wen-Xing; XU Qing; GUO Hong-Ju

    2005-01-01

    @@ We examine the phase-dependent effects in resonance fluorescence of a two-level atom driven by a trichromatic modulated field. It is shown that the fluorescence spectrum depends crucially on the sum of relative phases of the sideband components compared to the central component, not simply on the respective phases. The appearance or disappearance of the central peak and the selective elimination of the sideband peaks are achieved simply by varying the sum phase. Once the sum phase is fixed, the spectrum keeps its features unchanged regardless of the respective relative phases.

  19. Colorful Polyelectrolytes: An Atom Transfer Radical Polymerization Route to Fluorescent Polystyrene Sulfonate.

    Science.gov (United States)

    Huberty, Wayne; Tong, Xiaowei; Balamurugan, Sreelatha; Deville, Kyle; Russo, Paul S; Zhang, Donghui

    2016-03-01

    A labeled green fluorescent polystyrene sulfonate (LNaPSS) has been synthesized using atom transfer radical polymerization of a styrene sulfonate monomer with a fluorescent co-monomer, fluorescein thiocyanate-vinyl aniline. As a result this 100 % sulfonated polymer contains no hydrophobic patches along the chain backbone besides the fluorescent marker itself. The concentration of the fluorescent monomer was kept low to maintain the characteristic properties of the anionic polyelectrolyte, LNaPSS. ATRP conditions facilitated the production of polymers spanning a range of molecular weights from 35,000 to 175,000 in gram-scale batches with polydispersity indices of 1.01-1.24. Molecular weight increased with the monomer to initiator ratio. Gel permeation chromatography results show a unimodal distribution, and the polymer structure was also confirmed by (1)H NMR and FT-IR spectroscopy. Fluorescence spectroscopy confirmed covalent bonding of fluorescein isothiocyanate to the polymer, indicating that the polymer is suitable as a probe in fluorescence microscopy. To demonstrate this ability, the polymer was used to locate structural features in salt crystals formed during drying, as in the evaporation of sea mist. A second application to probe diffusion studies is also demonstrated.

  20. Fluorescence (TALIF) measurement of atomic hydrogen concentration in a coplanar surface dielectric barrier discharge

    Science.gov (United States)

    Mrkvičková, M.; Ráheľ, J.; Dvořák, P.; Trunec, D.; Morávek, T.

    2016-10-01

    Spatially and temporally resolved measurements of atomic hydrogen concentration above the dielectric of coplanar barrier discharge are presented for atmospheric pressure in 2.2% H2/Ar. The measurements were carried out in the afterglow phase by means of two-photon absorption laser-induced fluorescence (TALIF). The difficulties of employing the TALIF technique in close proximity to the dielectric surface wall were successfully addressed by taking measurements on a suitable convexly curved dielectric barrier, and by proper mathematical treatment of parasitic signals from laser-surface interactions. It was found that the maximum atomic hydrogen concentration is situated closest to the dielectric wall from which it gradually decays. The maximum absolute concentration was more than 1022 m-3. In the afterglow phase, the concentration of atomic hydrogen above the dielectric surface stays constant for a considerable time (10 μs-1 ms), with longer times for areas situated farther from the dielectric surface. The existence of such a temporal plateau was explained by the presented 1D model: the recombination losses of atomic hydrogen farther from the dielectric surface are compensated by the diffusion of atomic hydrogen from regions close to the dielectric surface. The fact that a temporal plateau exists even closest to the dielectric surface suggests that the dielectric surface acts as a source of atomic hydrogen in the afterglow phase.

  1. Communication: Angular momentum alignment and fluorescence polarization of alkali atoms photodetached from helium nanodroplets

    Energy Technology Data Exchange (ETDEWEB)

    Hernando, Alberto; Beswick, J. Alberto; Halberstadt, Nadine [LCAR-IRSAMC, Université Toulouse 3 - Paul Sabatier and CNRS, 31062 Toulouse (France)

    2013-12-14

    The theory of photofragments angular momentum polarization is applied to the photodetachment of an electronically excited alkali atom from a helium nanocluster (N = 200). The alignment of the electronic angular momentum of the bare excited alkali atoms produced is calculated quantum mechanically by solving the excited states coupled equations with potentials determined by density functional theory (DFT). Pronounced oscillations as a function of excitation energy are predicted for the case of Na@(He){sub 200}, in marked contrast with the absorption cross-section and angular distribution of the ejected atoms which are smooth functions of the energy. These oscillations are due to quantum interference between different coherently excited photodetachment pathways. Experimentally, these oscillations should be reflected in the fluorescence polarization and polarization-resolved photoelectron yield of the ejected atoms, which are proportional to the electronic angular momentum alignment. In addition, this result is much more general than the test case of NaHe{sub 200} studied here. It should be observable for larger droplets, for higher excited electronic states, and for other alkali as well as for alkali-earth atoms. Detection of these oscillations would show that the widely used pseudo-diatomic model can be valid beyond the prediction of absorption spectra and could help in interpreting parts of the dynamics, as already hinted by some experimental results on angular anisotropy of bare alkali fragments.

  2. Communication: angular momentum alignment and fluorescence polarization of alkali atoms photodetached from helium nanodroplets.

    Science.gov (United States)

    Hernando, Alberto; Beswick, J Alberto; Halberstadt, Nadine

    2013-12-14

    The theory of photofragments angular momentum polarization is applied to the photodetachment of an electronically excited alkali atom from a helium nanocluster (N = 200). The alignment of the electronic angular momentum of the bare excited alkali atoms produced is calculated quantum mechanically by solving the excited states coupled equations with potentials determined by density functional theory (DFT). Pronounced oscillations as a function of excitation energy are predicted for the case of Na@(He)200, in marked contrast with the absorption cross-section and angular distribution of the ejected atoms which are smooth functions of the energy. These oscillations are due to quantum interference between different coherently excited photodetachment pathways. Experimentally, these oscillations should be reflected in the fluorescence polarization and polarization-resolved photoelectron yield of the ejected atoms, which are proportional to the electronic angular momentum alignment. In addition, this result is much more general than the test case of NaHe200 studied here. It should be observable for larger droplets, for higher excited electronic states, and for other alkali as well as for alkali-earth atoms. Detection of these oscillations would show that the widely used pseudo-diatomic model can be valid beyond the prediction of absorption spectra and could help in interpreting parts of the dynamics, as already hinted by some experimental results on angular anisotropy of bare alkali fragments.

  3. Sub-cellular structure studied by combined atomic force-fluorescence microscopy

    Science.gov (United States)

    Trache, Andreea

    2009-03-01

    A novel experimental technique that integrates atomic force microscopy (AFM) with fluorescence imaging was used to study the role of extracellular matrix proteins in cellular organization. To understand the mechanism by which living cells sense mechanical forces, and how they respond and adapt to their environment, we developed a new technology able to investigate cellular behavior at sub-cellular level that integrates an AFM with total internal reflection fluorescence (TIRF) microscopy and fast-spinning disk (FSD) confocal microscopy. Live smooth muscle cells exhibited differences in focal adhesions and actin pattern depending on the extracellular matrix used for substrate coating. Data obtained by using the AFM-optical imaging integrated technique offer novel quantitative information that allows understanding the fundamental processes of cellular reorganization in response to extracellular matrix modulation. The integrated microscope presented here is broadly applicable across a wide range of molecular dynamic studies in any adherent live cells.

  4. Arsenic species analysis in porewaters and sediments using hydride generation atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    LIAO Meng-xia; DENG Tian-long

    2006-01-01

    It was observed that the atomic fluorescence emission due to As(Ⅴ) could has a 10% to 40% of fluorescence emission signal during the determination of As(Ⅲ) in the mixture of As(Ⅲ) and As(Ⅴ). Besides, interferes from heavy metals such as Pb(Ⅱ),Cu(Ⅱ) can cause severe increase of the signals as compared to the insignificant effects caused by Cd(Ⅱ), Zn(Ⅱ), Mn(Ⅱ) and Fe(Ⅲ). On the basis of further studies, the masking agent of 8-hydroxyquinoline was used as an efficient agent to eliminate interference of As(Ⅴ)emission and the heavy metal of Cu2+ and Pb2+ in the measurements of arsenic species. After a series standard additions and CRM researches, a sensitive and interference-free analytical procedure was developed for the speciation of arsenic in samples ofporewaters and sediments in Poyang Lake, China.

  5. X-ray fluorescence/Auger-electron coincidence spectroscopy of vacancy cascades in atomic argon

    Energy Technology Data Exchange (ETDEWEB)

    Arp, U. [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Electron and Optical Physics Div.; LeBrun, T.; Southworth, S.H.; Jung, M. [Argonne National Lab., IL (United States). Physics Div.; MacDonald, M.A. [E.P.S.R.C. Daresbury Lab., Warrington (United Kingdom)

    1996-12-01

    Argon L{sub 2.3}-M{sub 2.3}M{sub 2.3} Auger-electron spectra were measured in coincidence with K{alpha} fluorescent x-rays in studies of Ar K-shell vacancy decays at several photon energies above the K-threshold and on the 1s-4p resonance in atomic argon. The complex spectra recorded by conventional electron spectroscopy are greatly simplified when recorded in coincidence with fluorescent x-rays, allowing a more detailed analysis of the vacancy cascade process. The resulting coincidence spectra are compared with Hartree-Fock calculations which include shake-up transitions in the resonant case. Small energy shifts of the coincidence electron spectra are attributed to post-collision interaction with 1s photoelectrons.

  6. Real-time near-field terahertz imaging with atomic optical fluorescence

    Science.gov (United States)

    Wade, C. G.; Šibalić, N.; de Melo, N. R.; Kondo, J. M.; Adams, C. S.; Weatherill, K. J.

    2017-01-01

    Terahertz (THz) near-field imaging is a flourishing discipline, with applications from fundamental studies of beam propagation to the characterization of metamaterials and waveguides. Beating the diffraction limit typically involves rastering structures or detectors with length scale shorter than the radiation wavelength; in the THz domain this has been achieved using a number of techniques including scattering tips and apertures. Alternatively, mapping THz fields onto an optical wavelength and imaging the visible light removes the requirement for scanning a local probe, speeding up image collection times. Here, we report THz-to-optical conversion using a gas of highly excited Rydberg atoms. By collecting THz-induced optical fluorescence we demonstrate a real-time image of a THz standing wave and use well-known atomic properties to calibrate the THz field strength.

  7. Electrochemical hydride generation atomic fluorescence spectrometry for detection of tin in canned foods using polyaniline-modified lead cathode.

    Science.gov (United States)

    Jiang, Xianjuan; Gan, Wuer; Wan, Lingzhong; Deng, Yun; Yang, Qinghua; He, Youzhao

    2010-12-15

    An electrochemical hydride generation system with polyaniline-modified lead cathode was developed for tin determination by coupling with atomic fluorescence spectrometry. The tin fluorescence signal intensity was improved evidently as the polyaniline membrane could facilitate the transformation process from atomic tin to the SnH(4) and prevent the aggradation of Sn atom on Pb electrode surface. The effects of experimental parameters and interferences have been studied. The limit of detection (LOD) was 1.5 ng mL(-1) (3σ) and the relative standard deviation (RSD) was 3.3% for 11 consecutive measurements of 50 ng mL(-1) Sn(IV) standard solution.

  8. Pressure broadening of atomic oxygen two-photon absorption laser induced fluorescence

    Science.gov (United States)

    Marinov, Daniil; Drag, Cyril; Blondel, Christophe; Guaitella, Olivier; Golda, Judith; Klarenaar, Bart; Engeln, Richard; Schulz-von der Gathen, Volker; Booth, Jean-Paul

    2016-12-01

    Atomic oxygen, considered to be a determining reactant in plasma applications at ambient pressure, is routinely detected by two-photon absorption laser induced fluorescence (TALIF). Here, pressure broadening of the (2p 4 3 P 2  →  3p 3 P J=0,1,2) two-photon transition in oxygen atoms was investigated using a high-resolution TALIF technique in normal and Doppler-free configurations. The pressure broadening coefficients determined were {γ{{\\text{O}2}}}   =  0.40  ±  0.08  cm-1/bar for oxygen molecules and {γ\\text{He}}   =  0.46  ±  0.03 cm-1/bar for helium atoms. These correspond to pressure broadening rate constants k\\text{PB}{{\\text{O}2}}   =  9 · 10-9 cm3 s-1 and k\\text{PB}\\text{He}   =  4 · 10-9 cm3 s-1, respectively. The well-known quenching rate constants of O(3p 3 P J ) by O2 and He are at least one order of magnitude smaller, which signifies that non-quenching collisions constitute the main line-broadening mechanism. In addition to providing new insights into collisional processes of oxygen atoms in electronically excited 3p 3 P J state, reported pressure broadening parameters are important for quantification of oxygen TALIF line profiles when both collisional and Doppler broadening mechanisms are important. Thus, the Doppler component (and hence the temperature of oxygen atoms) can be accurately determined from high resolution TALIF measurements in a broad range of conditions.

  9. Real-Time Near-Field Terahertz Imaging with Atomic Optical Fluorescence

    CERN Document Server

    Wade, Christopher G; de Melo, Natalia R; Kondo, Jorge M; Adams, Charles S; Weatherill, Kevin J

    2016-01-01

    Terahertz (THz) near-field imaging is a flourishing discipline [1], with applications from fundamental studies of beam propagation [2,3] to the characterisation of metameterials [4,5] and waveguides [6,7]. Beating the diffraction limit typically involves rastering structures or detectors with length scale shorter than the radiation wavelength; in the THz domain this has been achieved using a number of techniques including scattering tips [8,9] and apertures [10]. Alternatively, mapping THz fields onto an optical wavelength and imaging the visible light removes the requirement for scanning a local probe, speeding up image collection times [11,12]. Here we report THz to optical conversion using a gas of highly excited `Rydberg' atoms. By collecting THz-induced optical fluorescence we demonstrate a real-time image of a THz standing wave and we use well-known atomic properties to calibrate the THz field strength. The mono-atomic gas does not distort the THz field and offers the potential to immerse structures wit...

  10. A novel fluorescence "on-off-on" chemosensor for Hg(2+)via a water-assistant blocking heavy atom effect.

    Science.gov (United States)

    Wu, Chong; Zhao, Jiang-Lin; Jiang, Xue-Kai; Wang, Chuan-Zeng; Ni, Xin-Long; Zeng, Xi; Redshaw, Carl; Yamato, Takehiko

    2016-10-14

    Upper rim pyrene-functionalized hexahomotrioxacalix[3]arene L was synthesized via Click chemistry, and its fluorescence behaviors toward several common metal cations were investigated. L exhibited a significant fluorescence quenching response to Hg(2+) in CH3CN solution, which was unaffected by the coexistence of other competitive metal cations. Thus, L can be utilized as a highly selective and sensitive fluorescent chemosensor for Hg(2+) with a detection limit in the nM level. Interestingly, the quenched fluorescence emission can be successfully revived upon the addition of water. In this process, the heavy atom effect of Hg(2+) can be blocked by further coordination of a water molecule and resulted in the revival of the fluorescence emission of L/Hg(2+) complex. Particularly, other polar solvents such as CH3OH and CH3CH2OH also have the ability to revive the fluorescence emission of the L/Hg(2+) complex, but on a much smaller scale than observed for H2O. The heavy atom effect and blocking thereof were demonstrated within the same system by the use of a C3-symmetric homooxacalix[3]arene scaffold. The present studies provided further evidence for the blocking heavy atom effect.

  11. Simplified approach to double jumps for fluorescing dipole-dipole interacting atoms

    CERN Document Server

    Hannstein, V; Hannstein, Volker; Hegerfeldt, Gerhard C.

    2006-01-01

    A simplified scheme for the investigation of cooperative effects in the quantum jump statistics of small numbers of fluorescing atoms and ions in a trap is presented. It allows the analytic treatment of three dipole-dipole interacting four-level systems which model the relevant level scheme of Ba+ ions. For the latter, a huge rate of double and triple jumps was reported in a former experiment and the huge rate was attributed to the dipole-dipole interaction. Our theoretical results show that the effect of the dipole-dipole interaction on these rates is at most 5% and that for the parameter values of the experiment there is practically no effect. Consequently it seems that the dipole-dipole interaction can be ruled out as a possible explanation for the huge rates reported in the experiment.

  12. Electrochemical hydride generation atomic fluorescence spectrometry for detection of tin in canned foods using polyaniline-modified lead cathode

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Xianjuan [Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China); Gan Wuer, E-mail: wgan@ustc.edu.cn [Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wan Lingzhong; Deng Yun; Yang Qinghua; He Youzhao [Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2010-12-15

    An electrochemical hydride generation system with polyaniline-modified lead cathode was developed for tin determination by coupling with atomic fluorescence spectrometry. The tin fluorescence signal intensity was improved evidently as the polyaniline membrane could facilitate the transformation process from atomic tin to the SnH{sub 4} and prevent the aggradation of Sn atom on Pb electrode surface. The effects of experimental parameters and interferences have been studied. The limit of detection (LOD) was 1.5 ng mL{sup -1} (3{sigma}) and the relative standard deviation (RSD) was 3.3% for 11 consecutive measurements of 50 ng mL{sup -1} Sn(IV) standard solution.

  13. Elasticity Maps of Living Neurons Measured by Combined Fluorescence and Atomic Force Microscopy

    CERN Document Server

    Spedden, Elise; Naumova, Elena N; Kaplan, David L; Staii, Cristian

    2013-01-01

    Detailed knowledge of mechanical parameters such as cell elasticity, stiffness of the growth substrate, or traction stresses generated during axonal extensions is essential for understanding the mechanisms that control neuronal growth. Here we combine Atomic Force Microscopy based force spectroscopy with Fluorescence Microscopy to produce systematic, high-resolution elasticity maps for three different types of live neuronal cells: cortical (embryonic rat), embryonic chick dorsal root ganglion, and P-19 (mouse embryonic carcinoma stem cells) neurons. We measure how the stiffness of neurons changes both during neurite outgrowth and upon disruption of microtubules of the cell. We find reversible local stiffening of the cell during growth, and show that the increase in local elastic modulus is primarily due to the formation of microtubules. We also report that cortical and P-19 neurons have similar elasticity maps, with elastic moduli in the range 0.1-2 kPa, with typical average values of 0.4 kPa (P-19) and 0.2 k...

  14. [Determination of mercury in shark liver by cold atom fluorescence spectrometry after microwave dissolution].

    Science.gov (United States)

    Weng, Di

    2005-12-01

    The conditions for the determination of mercury in shark liver by cold atom fluorescence spectrometry (CAFS) with microwave dissolution were studied. After being dried completely, the method employed 2 mol x L(-1) HNO3-4 mol x L(-1) HCl as an oxidant, and with catalysis by V2O5, the samples were digested in a microwave oven. The mercury in absorption solution was reduced by SnCl2, and then was determined by CAFS at wavelength of 253.7 nm. 10% SnCl2 solution was used as a reductive agent for mercury. The linear range was 0-2.0 ng x mL(-1) mercury (r = 0.999 7). The detection limit was 0.05 ng x mL(-1), the relative standard deviation was 0.86%-2.22%, and the average recovery rate was 96.0%-108.5%. The method was suitable for the determination of mercury in shark liver.

  15. Novel Method for Indirect Determination of Iodine in Marine Products by Atomic Fluorescence Spectrometry

    Institute of Scientific and Technical Information of China (English)

    LU Jian-ping; TAN Fang-wei; TANG Qiong; JIANG Tian-cheng

    2013-01-01

    A method for the determination of iodine based upon compound H2HgI4,formed between I-and Hg2+ in nitric acid and extracted in methyl isobutyl ketone(MIBK),was developed via atomic fluorescence spectrometry(AFS).After the compound is reduced with potassium borohydrid(KBH4),the resultant mercury vapor was injected into the instrument and iodine was,therefore,indirectly determined.Experimental parameters such as the conditions of extraction reagents,aqueous phase acidity,elemental mercury diffusion temperature in a vial and other factors were investigated and optimized.Under the optimum experimental conditions,this method shows a detection limit of 0.038 μg/L iodine and a linear relationship between 0.04-20 μg/L.The method was applied to determining the iodine content in marine duck eggs,kelps,laver and Ganoderma lucidum spirulina,showing a relative standard deviation(RSD) of 2.15% and the recoveries in the range of 98.1%-102.5%.

  16. Determination of mercury in rice by cold vapor atomic fluorescence spectrometry after microwave-assisted digestion

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Maria Jose da [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain); Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Cidade Universitaria, 50740-550 Recife, PE (Brazil); Paim, Ana Paula S. [Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Cidade Universitaria, 50740-550 Recife, PE (Brazil); Pimentel, Maria Fernanda [Departamento de Engenharia Quimica, Universidade Federal de Pernambuco, Recife, PE (Brazil); Cervera, M. Luisa, E-mail: m.luisa.cervera@uv.es [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain); Guardia, Miguel de la [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain)

    2010-05-14

    A cold vapor atomic fluorescence spectrometry method (CV-AFS) has been developed for the determination of Hg in rice samples at a few ng g{sup -1} concentration level. The method is based on the previous digestion of samples in a microwave oven with HNO{sub 3} and H{sub 2}O{sub 2} followed by dilution with water containing KBr/KBrO{sub 3} and hydroxylamine and reduction with SnCl{sub 2} in HCl using external calibration. The matrix interferences and the effect of nitrogen oxide vapors have been evaluated and the method validated using a certified reference material. The limit of detection of the method was 0.9 ng g{sup -1} with a recovery percentage of 95 {+-} 4% at an added concentration of 5 ng g{sup -1}. The concentration level of Hg found in 24 natural rice samples from different origin ranged between 1.3 and 7.8 ng g{sup -1}.

  17. Determination of inorganic species of Sb and Te in cereals by hydride generation atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Reyes, Mariela N.M.; Cervera, Maria L.; Guardia, Miguel de la, E-mail: m.luisa.cervera@uv.e [University of Valencia, Valencia (Spain). Dept. of Analytical Chemistry

    2011-07-01

    A non-chromatographic fast, sensitive and easy method has been developed for the determination of Sb(III), Sb(V), Te(IV) and Te(VI) in cereal samples. The procedure is based on ultrasound assisted extraction and determination by hydride generation atomic fluorescence spectrometry (HG AFS). Preliminary studies were made in order to get the best extraction efficiency using 1 mol L{sup -1} phosphoric acid, 1 mol L{sup -1} nitric acid, aqua regia, 1 mol L{sup -1} sulfuric acid and 6 mol L{sup -1} hydrochloric acid. The extraction with aqua regia showed a clear interconversion of the species during the process, being H{sub 2}SO{sub 4} the best extractant with efficiencies greater than 90% from the total content of Sb and Te quantified previously and without species interconversion. This point was checked by recovery experiments at different spiked levels. The method provided limits of detection values from 0.1 to 0.5 ng g{sup -1} with relative standard deviation values from 5.4 to 9.2% of 10 independent analysis of samples containing few ng g-1 of Sb and Te species. (author)

  18. Correlated fluorescence-atomic force microscopy studies of the clathrin mediated endocytosis in SKMEL cells

    Science.gov (United States)

    Hor, Amy; Luu, Anh; Kang, Lin; Scott, Brandon; Bailey, Elizabeth; Hoppe, Adam; Smith, Steve

    2017-02-01

    Clathrin-mediated endocytosis (CME) is one of the central pathways for cargo transport into cells, and plays a major role in the maintenance of cellular functions, such as intercellular signaling, nutrient intake, and turnover of plasma membrane in cells. The clathrin-mediated endocytosis process involves invagination and formation of clathrin-coated vesicles. However, the biophysical mechanisms of vesicle formation are still debated. Currently, there are two models describing membrane bending during the formation of clathrin cages: the first involves the deposition of all clathrin molecules to the plasma membrane, forming a flat lattice prior to membrane bending, whereas in the second model, membrane bending happens simultaneously as the clathrin arrives to the site to form a clathrin-coated cage. We investigate clathrin vesicle formation mechanisms through the utilization of tapping-mode atomic force microscopy for high resolution topographical imaging in neutral buffer solution of unroofed cells exposing the inner membrane, combined with fluorescence imaging to definitively label intracellular constituents with specific fluorophores (actin filaments labeled with green phalloidin and clathrin coated vesicles with the fusion protein Tq2) in SKMEL (Human Melanoma) cells. An extensive statistical survey of many hundreds of CME events, at various stages of progression, are observed via this method, allowing inferences about the dominant mechanisms active in CME in SKMEL cells. Results indicate a mixed model incorporating aspects of both the aforementioned mechanisms for CME.

  19. [Research on optimization of mathematical model of flow injection-hydride generation-atomic fluorescence spectrometry].

    Science.gov (United States)

    Cui, Jian; Zhao, Xue-Hong; Wang, Yan; Xiao, Ya-Bing; Jiang, Xue-Hui; Dai, Li

    2014-01-01

    Flow injection-hydride generation-atomic fluorescence spectrometry was a widely used method in the industries of health, environmental, geological and metallurgical fields for the merit of high sensitivity, wide measurement range and fast analytical speed. However, optimization of this method was too difficult as there exist so many parameters affecting the sensitivity and broadening. Generally, the optimal conditions were sought through several experiments. The present paper proposed a mathematical model between the parameters and sensitivity/broadening coefficients using the law of conservation of mass according to the characteristics of hydride chemical reaction and the composition of the system, which was proved to be accurate as comparing the theoretical simulation and experimental results through the test of arsanilic acid standard solution. Finally, this paper has put a relation map between the parameters and sensitivity/broadening coefficients, and summarized that GLS volume, carrier solution flow rate and sample loop volume were the most factors affecting sensitivity and broadening coefficients. Optimizing these three factors with this relation map, the relative sensitivity was advanced by 2.9 times and relative broadening was reduced by 0.76 times. This model can provide a theoretical guidance for the optimization of the experimental conditions.

  20. Laser-induced atomic fragment fluorescence spectroscopy: a facile technique for molecular spectroscopy of spin-forbidden states.

    Science.gov (United States)

    Zhang, Qun; Chen, Yang; Keil, Mark

    2009-03-01

    Spectra of spin-forbidden and spin-allowed transitions in the mixed b (3)Pi(u) approximately A (1)Sigma(u)(+) state of Na(2) are measured separately by two-photon excitation using a single tunable dye laser. The two-photon excitation produces Na(*)(3p) by photodissociation, which is easily and sensitively detected by atomic fluorescence. At low laser power, only the A (1)Sigma(u)(+) state is excited, completely free of triplet excitation. At high laser power, photodissociation via the intermediate b (3)Pi(u) triplet state becomes much more likely, effectively "switching" the observations from singlet spectroscopy to triplet spectroscopy with only minor apparatus changes. This technique of perturbation-assisted laser-induced atomic fragment fluorescence may therefore be especially useful as a general vehicle for investigating perturbation-related physics pertinent to the spin-forbidden states, as well as for studying allowed and forbidden states of other molecules.

  1. Correlative atomic force and confocal fluorescence microscopy: single molecule imaging and force induced spectral shifts (Conference Presentation)

    Science.gov (United States)

    Basché, Thomas; Hinze, Gerald; Stöttinger, Sven

    2016-09-01

    A grand challenge in nanoscience is to correlate structure or morphology of individual nano-sized objects with their photo-physical properties. An early example have been measurements of the emission spectra and polarization of single semiconductor quantum dots as well as their crystallographic structure by a combination of confocal fluorescence microscopy and transmission electron microscopy.[1] Recently, the simultaneous use of confocal fluorescence and atomic force microscopy (AFM) has allowed for correlating the morphology/conformation of individual nanoparticle oligomers or molecules with their photo-physics.[2, 3] In particular, we have employed the tip of an AFM cantilever to apply compressive stress to single molecules adsorbed on a surface and follow the effect of the impact on the electronic states of the molecule by fluorescence spectroscopy.[3] Quantum mechanical calculations corroborate that the spectral changes induced by the localized force can be associated to transitions among the different possible conformers of the adsorbed molecule.

  2. [Using atomic fluorescence spectrometry to study the spatial distribution of As and Hg in orchard soils].

    Science.gov (United States)

    Zhao, Xi-Mei; Lü, Chun-Yan; Liu, Qing; Zhu, Xi-Cun

    2014-02-01

    Aqua regia digestion, double channels-atomic fluorescence spectrometry method was used to determine the concentrations of As and Hg in orchard soils of Qixia City - the main apple production area of Shandong province. Validate The detection limitation, accuracy and precision of the method were validated, the spatial distribution was analyzed, and the characteristics of As and Hg pollution in Qixia orchard soils were assessed. The results showed that the range of As concentration in Qixia soils is between 2.79 and 20.93 mg x kg(-1), the average concentration is 10.59 mg x kg(-1), the range of Hg concentration in Qixia soil is between 0.01 and 0.79 mg x kg(-1), the average concentration is 0.12 mg x kg(-1). The variation of As concentration in soils is small, whereas that of Hg concentration is large. Frequency distribution graphics of As and Hg showed that the concentration of As in soils is according with the normal distribution approximately and the concentrations are mostly between 7 and 15 mg x kg(-1), the concentration of Hg in soil isn't according with the normal distribution and the concentrations are mostly between 0.03 and 0.21 mg x kg(-1). The correlations between the concentrations of As or Hg in soils and the nutrient are not significant and there is no significant correlation even between As and Hg. Based on the environmental technical terms for green food production area, the As concentration in orchard soil of Qixia City is at clean level, but there are 4.76% of sample points with Hg pollution index exceeding 1, and this should be attracted the attention of the administrators.

  3. High performance liquid chromatography--atomic fluorescence spectrometric determination of arsenic species in beer samples

    Energy Technology Data Exchange (ETDEWEB)

    Melo Coelho, N.M.; Parrilla, Carmen; Cervera, M.L.; Pastor, A.; Guardia, M. de la

    2003-04-10

    A method has been developed for the direct determination of As(III), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and As(V) in beers by hydride generation--atomic fluorescence spectrometry after separation of arsenic species by high performance liquid chromatography. Compounds were separated by anion-exchange chromatography with isocratic elution using KH{sub 2}PO{sub 4}/K{sub 2}HPO{sub 4} as mobile phase with elution times of 1.67, 2.08, 6.52 and 10.72 min for As(III), DMA, MMA and As(V), respectively. Parameters affecting the hydride generation of all arsenic species were studied and the best conditions were established as a reaction coil of 150 cm, for a sample injected volume of 100 {mu}l, a 4.0% (m/v) solution of sodium tetrahydroborate and 2.0 mol l{sup -1} hydrochloric acid with flow rates of 2.7 and 1.7 ml min{sup -1}, respectively and a flow rate of 500 ml min{sup -1} for the argon carrier gas. Under the best experimental conditions, the detection limit was found to be 0.12, 0.20, 0.27 and 0.39 {mu}g l{sup -1} for As(III), DMA, MMA and As(V), respectively. The relative standard deviation for eight independent determinations varied from 3.9 till 8.9% for species considered at a concentration level of 10.0 {mu}g l{sup -1}. Recovery and comparative studies evidenced that the method is suitable for the accurate determination of arsenic species in water and beer samples.

  4. Collective resonance fluorescence in small and dense atom clouds: Comparison between theory and experiment

    CERN Document Server

    Jenkins, S D; Javanainen, J; Jennewein, S; Bourgain, R; Pellegrino, J; Sortais, Y R P; Browaeys, A

    2016-01-01

    We study the emergence of a collective optical response of a cold and dense $^{87}$Rb atomic cloud to a near-resonant low-intensity light when the atom number is gradually increased. Experimental observations are compared with microscopic stochastic simulations of recurrent scattering processes between the atoms that incorporate the atomic multilevel structure and the optical measurement setup. We analyze the optical response of an inhomogeneously-broadened gas and find that the experimental observations of the resonance line shifts and the total collected scattered light intensity in cold atom clouds substantially deviate from those of thermal atomic ensembles, indicating strong light-induced resonant dipole-dipole interactions between the atoms. At high densities, the simulations also predict a significantly slower decay of light-induced excitations in cold than in thermal atom clouds. The role of dipole-dipole interactions is discussed in terms of resonant coupling examples and the collective radiative exc...

  5. Flow injection-chemical vapor generation atomic fluorescence spectrometry hyphenated system for organic mercury determination: A step forward

    Energy Technology Data Exchange (ETDEWEB)

    Angeli, Valeria [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici - ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Biagi, Simona [National Research Council of Italy, C.N.R., Istituto per i Processi Chimico-Fisici - IPCF-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Ghimenti, Silvia [University of Pisa, Department of Chemistry and Industrial Chemistry, Via Risorgimento 35, 56126 Pisa (Italy); Onor, Massimo; D' Ulivo, Alessandro [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici - ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Bramanti, Emilia, E-mail: bramanti@pi.iccom.cnr.it [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici - ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy)

    2011-11-15

    Monomethylmercury and ethylmercury were determined on line using flow injection-chemical vapor generation atomic fluorescence spectrometry without neither requiring a pre-treatment with chemical oxidants, nor UV/MW additional post column interface, nor organic solvents, nor complexing agents, such as cysteine. Inorganic mercury, monomethylmercury and ethylmercury were detected by atomic fluorescence spectrometry in an Ar/H{sub 2} miniaturized flame after sodium borohydride reduction to Hg{sup 0}, monomethylmercury hydride and ethylmercury hydride, respectively. The effect of mercury complexing agent such as cysteine, ethylendiaminotetracetic acid and HCl with respect to water and Ar/H{sub 2} microflame was investigated. The behavior of inorganic mercury, monomethylmercury and ethylmercury and their cysteine-complexes was also studied by continuous flow-chemical vapor generation atomic fluorescence spectrometry in order to characterize the reduction reaction with tetrahydroborate. When complexed with cysteine, inorganic mercury, monomethylmercury and ethylmercury cannot be separately quantified varying tetrahydroborate concentration due to a lack of selectivity, and their speciation requires a pre-separation stage (e.g. a chromatographic separation). If not complexed with cysteine, monomethylmercury and ethylmercury cannot be separated, as well, but their sum can be quantified separately with respect to inorganic mercury choosing a suitable concentration of tetrahydroborate (e.g. 10{sup -5} mol L{sup -1}), thus allowing the organic/inorganic mercury speciation. The detection limits of the flow injection-chemical vapor generation atomic fluorescence spectrometry method were about 45 nmol L{sup -1} (as mercury) for all the species considered, a relative standard deviation ranging between 1.8 and 2.9% and a linear dynamic range between 0.1 and 5 {mu}mol L{sup -1} were obtained. Recoveries of monomethylmercury and ethylmercury with respect to inorganic mercury were

  6. Flow injection-chemical vapor generation atomic fluorescence spectrometry hyphenated system for organic mercury determination: A step forward

    Science.gov (United States)

    Angeli, Valeria; Biagi, Simona; Ghimenti, Silvia; Onor, Massimo; D'Ulivo, Alessandro; Bramanti, Emilia

    2011-11-01

    Monomethylmercury and ethylmercury were determined on line using flow injection-chemical vapor generation atomic fluorescence spectrometry without neither requiring a pre-treatment with chemical oxidants, nor UV/MW additional post column interface, nor organic solvents, nor complexing agents, such as cysteine. Inorganic mercury, monomethylmercury and ethylmercury were detected by atomic fluorescence spectrometry in an Ar/H 2 miniaturized flame after sodium borohydride reduction to Hg 0, monomethylmercury hydride and ethylmercury hydride, respectively. The effect of mercury complexing agent such as cysteine, ethylendiaminotetracetic acid and HCl with respect to water and Ar/H 2 microflame was investigated. The behavior of inorganic mercury, monomethylmercury and ethylmercury and their cysteine-complexes was also studied by continuous flow-chemical vapor generation atomic fluorescence spectrometry in order to characterize the reduction reaction with tetrahydroborate. When complexed with cysteine, inorganic mercury, monomethylmercury and ethylmercury cannot be separately quantified varying tetrahydroborate concentration due to a lack of selectivity, and their speciation requires a pre-separation stage (e.g. a chromatographic separation). If not complexed with cysteine, monomethylmercury and ethylmercury cannot be separated, as well, but their sum can be quantified separately with respect to inorganic mercury choosing a suitable concentration of tetrahydroborate (e.g. 10 - 5 mol L - 1 ), thus allowing the organic/inorganic mercury speciation. The detection limits of the flow injection-chemical vapor generation atomic fluorescence spectrometry method were about 45 nmol L - 1 (as mercury) for all the species considered, a relative standard deviation ranging between 1.8 and 2.9% and a linear dynamic range between 0.1 and 5 μmol L - 1 were obtained. Recoveries of monomethylmercury and ethylmercury with respect to inorganic mercury were never less than 91%. Flow injection

  7. Atoms

    Institute of Scientific and Technical Information of China (English)

    刘洪毓

    2007-01-01

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

  8. New Homogeneous Standards by Atomic Layer Deposition for Synchrotron X-ray Fluorescence and Absorption Spectroscopies.

    Energy Technology Data Exchange (ETDEWEB)

    Butterworth, A.L.; Becker, N.; Gainsforth, Z.; Lanzirotti, A.; Newville, M.; Proslier, T.; Stodolna, J.; Sutton, S.; Tyliszczak, T.; Westphal, A.J.; Zasadzinski, J. (UCB)

    2012-03-13

    Quantification of synchrotron XRF analyses is typically done through comparisons with measurements on the NIST SRM 1832/1833 thin film standards. Unfortunately, these standards are inhomogeneous on small scales at the tens of percent level. We are synthesizing new homogeneous multilayer standards using the Atomic Layer Deposition technique and characterizing them using multiple analytical methods, including ellipsometry, Rutherford Back Scattering at Evans Analytical, Synchrotron X-ray Fluorescence (SXRF) at Advanced Photon Source (APS) Beamline 13-ID, Synchrotron X-ray Absorption Spectroscopy (XAS) at Advanced Light Source (ALS) Beamlines 11.0.2 and 5.3.2.1 and by electron microscopy techniques. Our motivation for developing much-needed cross-calibration of synchrotron techniques is borne from coordinated analyses of particles captured in the aerogel of the NASA Stardust Interstellar Dust Collector (SIDC). The Stardust Interstellar Dust Preliminary Examination (ISPE) team have characterized three sub-nanogram, {approx}1{micro}m-sized fragments considered as candidates to be the first contemporary interstellar dust ever collected, based on their chemistries and trajectories. The candidates were analyzed in small wedges of aerogel in which they were extracted from the larger collector, using high sensitivity, high spatial resolution >3 keV synchrotron x-ray fluorescence spectroscopy (SXRF) and <2 keV synchrotron x-ray transmission microscopy (STXM) during Stardust ISPE. The ISPE synchrotron techniques have complementary capabilities. Hard X-ray SXRF is sensitive to sub-fg mass of elements Z {ge} 20 (calcium) and has a spatial resolution as low as 90nm. X-ray Diffraction data were collected simultaneously with SXRF data. Soft X-ray STXM at ALS beamline 11.0.2 can detect fg-mass of most elements, including cosmochemically important oxygen, magnesium, aluminum and silicon, which are invisible to SXRF in this application. ALS beamline 11.0.2 has spatial resolution

  9. Photolytic-interference-free, femtosecond, two-photon laser-induced fluorescence imaging of atomic oxygen in flames

    Science.gov (United States)

    Kulatilaka, Waruna D.; Roy, Sukesh; Jiang, Naibo; Gord, James R.

    2016-02-01

    Ultrashort-pulse lasers are well suited for nonlinear diagnostic techniques such as two-photon laser-induced fluorescence (TPLIF) because the signals generated scale as the laser intensity squared. Furthermore, the broad spectral bandwidths associated with nearly Fourier-transform-limited ultrashort pulses effectively contribute to efficient nonlinear excitation by coupling through a large number of in-phase photon pairs, thereby producing strong fluorescence signals. Additionally, femtosecond (fs)-duration amplified laser systems typically operate at 1-10 kHz repetition rates, enabling high-repetition-rate imaging in dynamic environments. In previous experiments, we have demonstrated utilization of fs pulses for kilohertz (kHz)-rate, interference-free imaging of atomic hydrogen (H) in flames. In the present study, we investigate the utilization of fs-duration pulses to photolytic-interference-free TPLIF imaging of atomic oxygen (O). In TPLIF of O, photodissociation of vibrationally excited carbon dioxide (CO2) is known to be the prominent interference that produces additional O atoms in the medium. We have found that through the use of fs excitation, such interferences can be virtually eliminated in premixed laminar methane flames, which paves the way for two-dimensional imaging of O at kHz data rates. Such measurements can provide critical data for validating complex, multidimensional turbulent-combustion models as well as for investigating flame dynamics in practical combustion devices.

  10. Direct determination of mercury in white vinegar by matrix assisted photochemical vapor generation atomic fluorescence spectrometry detection

    Energy Technology Data Exchange (ETDEWEB)

    Liu Qingyang, E-mail: liuqingyang0807@yahoo.com.c [Beijing Center for Physical and Chemical Analysis, Beijing 100089 (China)

    2010-07-15

    This paper proposes the use of photochemical vapor generation with acetic acid as sample introduction for the direct determination of ultra-trace mercury in white vinegars by atomic fluorescence spectrometry. Under ultraviolet irradiation, the sample matrix (acetic acid) can reduce mercury ion to atomic mercury Hg{sup 0}, which is swept by argon gas into an atomic fluorescence spectrometer for subsequent analytical measurements. The effects of several factors such as the concentration of acetic acid, irradiation time, the flow rate of the carrier gas and matrix effects were discussed and optimized to give detection limits of 0.08 ng mL{sup -1} for mercury. Using the experimental conditions established during the optimization (3% v/v acetic acid, 30 s irradiation time and 20 W mercury lamp), the precision levels, expressed as relative standard deviation, were 4.6% (one day) and 7.8% (inter-day) for mercury (n = 9). Addition/recovery tests for evaluation of the accuracy were in the range of 92-98% for mercury. The method was also validated by analysis of vinegar samples without detectable amount of Hg spiked with aqueous standard reference materials (GBW(E) 080392 and GBW(E) 080393). The results were also compared with those obtained by acid digestion procedure and determination of mercury by ICP-MS. There was no significant difference between the results obtained by the two methods based on a t-test (at 95% confidence level).

  11. Direct determination of mercury in white vinegar by matrix assisted photochemical vapor generation atomic fluorescence spectrometry detection

    Science.gov (United States)

    Liu, Qingyang

    2010-07-01

    This paper proposes the use of photochemical vapor generation with acetic acid as sample introduction for the direct determination of ultra-trace mercury in white vinegars by atomic fluorescence spectrometry. Under ultraviolet irradiation, the sample matrix (acetic acid) can reduce mercury ion to atomic mercury Hg 0, which is swept by argon gas into an atomic fluorescence spectrometer for subsequent analytical measurements. The effects of several factors such as the concentration of acetic acid, irradiation time, the flow rate of the carrier gas and matrix effects were discussed and optimized to give detection limits of 0.08 ng mL -1 for mercury. Using the experimental conditions established during the optimization (3% v/v acetic acid, 30 s irradiation time and 20 W mercury lamp), the precision levels, expressed as relative standard deviation, were 4.6% (one day) and 7.8% (inter-day) for mercury ( n = 9). Addition/recovery tests for evaluation of the accuracy were in the range of 92-98% for mercury. The method was also validated by analysis of vinegar samples without detectable amount of Hg spiked with aqueous standard reference materials (GBW(E) 080392 and GBW(E) 080393). The results were also compared with those obtained by acid digestion procedure and determination of mercury by ICP-MS. There was no significant difference between the results obtained by the two methods based on a t-test (at 95% confidence level).

  12. Laser-Excited Atomic Fluorescence and Ionization in a Graphite Furnace for the Determination of Metals and Nonmetals

    Science.gov (United States)

    Butcher, David James

    1990-01-01

    Here is reported novel instrumentation for atomic spectrometry that combined the use of a pulsed laser system as the light source and an electrothermal atomizer as the atom cell. The main goal of the research was to develop instrumentation that was more sensitive for elemental analysis than commercially available instruments and could be used to determine elements in real sample matrices. Laser excited atomic fluorescence spectrometry (LEAFS) in an electrothermal atomizer (ETA) was compared to ETA atomic absorption spectrometry (AAS) for the determination of thallium, manganese, and lead in food and agricultural standard reference materials (SRMs). Compared to ETA AAS, ETA LEAFS has a longer linear dynamic range (LDR) (5-7 orders of magnitude compared to 2-3 orders of magnitude) and higher sensitivity (10 ^{-16} to 10^{ -14} g as compared to 10^{ -13} to 10^{-11} g). Consequently, ETA LEAFS allows elemental analysis to be done over a wider range of concentrations with less dilution steps. Thallium was accurately determined in biological samples by ETA LEAFS at amounts five to one hundred times below the ETA AAS detection limit. ETA AAS and ETA LEAFS were compared for the determination of lead and manganese, and in general, the accuracies and precisions of ETA AAS were the same, with typical precisions between 3% and 6%. Fluorine was determined using laser excited molecular fluorescence spectrometry (LEMOFS) in an ETA. Molecular fluorescence from magnesium fluoride was collected, and the detection limit of 0.3 pg fluorine was two to six orders of magnitude more sensitive than other methods commonly used for the determination of fluorine. Significant interferences from ions were observed, but the sensitivity was high enough that fluorine could be determined in freeze dried urine SRMs by diluting the samples by a factor of one hundred to remove the interferences. Laser enhanced ionization (LEI) in an ETA was used for the determination of metals. For thallium, indium

  13. 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

    Science.gov (United States)

    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,…

  14. 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

    Science.gov (United States)

    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,…

  15. Photoluminescence Enhancement in Nanotextured Fluorescent SiC Passivated by Atomic Layer Deposited Al2O3 Films

    DEFF Research Database (Denmark)

    Lu, Weifang; Ou, Yiyu; Jokubavicius, Valdas

    2016-01-01

    The influence of thickness of atomic layer deposited Al2O3 films on nano-textured fluorescent 6H-SiC passivation is investigated. The passivation effect on the light emission has been characterized by photoluminescence and time-resolved photoluminescence at room temperature. The results show...... that 20nm thickness of Al2O3 layer is favorable to observe a large photoluminescence enhancement (25.9%) and long carrier lifetime (0.86ms). This is a strong indication for an interface hydrogenation that takes place during post-thermal annealing. These results show that an Al2O3 layer could serve...

  16. Total uncertainty budget calculation for the determination of mercury in incineration ash (BCR 176R) by atomic fluorescence spectrometry.

    Science.gov (United States)

    Tirez, Kristof; Beutels, Filip; Brusten, Wilfried; Noten, Bart; De Brucker, Nicole

    2002-11-01

    The mercury mass fraction has been determined by atomic fluorescence spectrometry (AFS) in the framework of the project "Certification of a reference material (trace elements in fly ash) in replacement of BCR CRM 176". Calculation of the uncertainty budget, as described in this manuscript, emphasizes a practical and realistic approach to estimation of uncertainty components on the basis of statistical assumptions. GUM Workbench software was used, and resulted in a mercury mass fraction of 1.58+/-0.11 mg kg(-1) (with coverage factor k=2.2, 95% probability) related to dry mass, submitted in the certification exercise. The calculated total uncertainty budget applies to analogous samples analyzed by this procedure.

  17. Spatially and Temporally Resolved Atomic Oxygen Measurements in Short Pulse Discharges by Two Photon Laser Induced Fluorescence

    Science.gov (United States)

    Lempert, Walter; Uddi, Mruthunjaya; Mintusov, Eugene; Jiang, Naibo; Adamovich, Igor

    2007-10-01

    Two Photon Laser Induced Fluorescence (TALIF) is used to measure time-dependent absolute oxygen atom concentrations in O2/He, O2/N2, and CH4/air plasmas produced with a 20 nanosecond duration, 20 kV pulsed discharge at 10 Hz repetition rate. Xenon calibrated spectra show that a single discharge pulse creates initial oxygen dissociation fraction of ˜0.0005 for air like mixtures at 40-60 torr total pressure. Peak O atom concentration is a factor of approximately two lower in fuel lean (φ=0.5) methane/air mixtures. In helium buffer, the initially formed atomic oxygen decays monotonically, with decay time consistent with formation of ozone. In all nitrogen containing mixtures, atomic oxygen concentrations are found to initially increase, for time scales on the order of 10-100 microseconds, due presumably to additional O2 dissociation caused by collisions with electronically excited nitrogen. Further evidence of the role of metastable N2 is demonstrated from time-dependent N2 2^nd Positive and NO Gamma band emission spectroscopy. Comparisons with modeling predictions show qualitative, but not quantitative, agreement with the experimental data.

  18. Speciation analysis of arsenic by selective hydride generation-cryotrapping-atomic fluorescence spectrometry with flame-in-gas-shield atomizer: achieving extremely low detection limits with inexpensive instrumentation.

    Science.gov (United States)

    Musil, Stanislav; Matoušek, Tomáš; Currier, Jenna M; Stýblo, Miroslav; Dědina, Jiří

    2014-10-21

    This work describes the method of a selective hydride generation-cryotrapping (HG-CT) coupled to an extremely sensitive but simple in-house assembled and designed atomic fluorescence spectrometry (AFS) instrument for determination of toxicologically important As species. Here, an advanced flame-in-gas-shield atomizer (FIGS) was interfaced to HG-CT and its performance was compared to a standard miniature diffusion flame (MDF) atomizer. A significant improvement both in sensitivity and baseline noise was found that was reflected in improved (4 times) limits of detection (LODs). The yielded LODs with the FIGS atomizer were 0.44, 0.74, 0.15, 0.17 and 0.67 ng L(-1) for arsenite, total inorganic, mono-, dimethylated As and trimethylarsine oxide, respectively. Moreover, the sensitivities with FIGS and MDF were equal for all As species, allowing for the possibility of single species standardization with arsenate standard for accurate quantification of all other As species. The accuracy of HG-CT-AFS with FIGS was verified by speciation analysis in two samples of bottled drinking water and certified reference materials, NRC CASS-5 (nearshore seawater) and SLRS-5 (river water) that contain traces of methylated As species. As speciation was in agreement with results previously reported and sums of all quantified species corresponded with the certified total As. The feasibility of HG-CT-AFS with FIGS was also demonstrated by the speciation analysis in microsamples of exfoliated bladder epithelial cells isolated from human urine. The results for the sums of trivalent and pentavalent As species corresponded well with the reference results obtained by HG-CT-ICPMS (inductively coupled plasma mass spectrometry).

  19. Determination and characterization of phytochelatins by liquid chromatography coupled with on line chemical vapour generation and atomic fluorescence spectrometric detection.

    Science.gov (United States)

    Bramanti, Emilia; Toncelli, Daniel; Morelli, Elisabetta; Lampugnani, Leonardo; Zamboni, Roberto; Miller, Keith E; Zemetra, Joseph; D'Ulivo, Alessandro

    2006-11-10

    Liquid chromatography (LC) coupled on line with UV/visible diode array detector (DAD) and cold vapour generation atomic fluorescence spectrometry (CVGAFS) has been developed for the speciation, determination and characterization of phytochelatins (PCs). The method is based on a bidimensional approach, e.g. on the analysis of synthetic PC solutions (apo-PCs and Cd(2+)-complexed PCs) (i) by size exclusion chromatography coupled to UV diode array detector (SEC-DAD); (ii) by the derivatization of PC -SH groups in SEC fractions by p-hydroxymercurybenzoate (PHMB) and the indirect detection of PC-PHMB complexes by reversed phase liquid chromatography coupled to atomic fluorescence detector (RPLC-CVGAFS). MALDI-TOF/MS (matrix assisted laser desorption ionization time of flight mass spectrometry) analysis of underivatized synthetic PC samples was performed in order have a qualitative information of their composition. Quantitative analysis of synthetic PC solutions has been performed on the basis of peak area of PC-PHMB complexes of the mercury specific chromatogram and calibration curve of standard solution of glutathione (GSH) complexed to PHMB (GS-PHMB). The limit of quantitation (LOQ) in terms of GS-PHMB complex was 90 nM (CV 5%) with an injection volume of 35 microL, corresponding to 3.2 pmol (0.97 ng) of GSH. The method has been applied to analysis of extracts of cell cultures from Phaeodactylum tricornutum grown in Cd-containing nutrient solutions, analysed by SEC-DAD-CVGAFS and RPLC-DAD-CVGAFS.

  20. Synchronizing atomic force microscopy force mode and fluorescence microscopy in real time for immune cell stimulation and activation studies

    Energy Technology Data Exchange (ETDEWEB)

    Cazaux, Séverine; Sadoun, Anaïs; Biarnes-Pelicot, Martine; Martinez, Manuel; Obeid, Sameh [Aix Marseille Université, LAI UM 61, Marseille F-13288 (France); Inserm, UMR-S 1067, Marseille F-13288 (France); CNRS, UMR 7333, Marseille F-13288 (France); Bongrand, Pierre [Aix Marseille Université, LAI UM 61, Marseille F-13288 (France); Inserm, UMR-S 1067, Marseille F-13288 (France); CNRS, UMR 7333, Marseille F-13288 (France); APHM, Hôpital de la Conception, Laboratoire d’Immunologie, Marseille F-13385 (France); Limozin, Laurent [Aix Marseille Université, LAI UM 61, Marseille F-13288 (France); Inserm, UMR-S 1067, Marseille F-13288 (France); CNRS, UMR 7333, Marseille F-13288 (France); Puech, Pierre-Henri, E-mail: pierre-henri.puech@inserm.fr [Aix Marseille Université, LAI UM 61, Marseille F-13288 (France); Inserm, UMR-S 1067, Marseille F-13288 (France); CNRS, UMR 7333, Marseille F-13288 (France)

    2016-01-15

    A method is presented for combining atomic force microscopy (AFM) force mode and fluorescence microscopy in order to (a) mechanically stimulate immune cells while recording the subsequent activation under the form of calcium pulses, and (b) observe the mechanical response of a cell upon photoactivation of a small G protein, namely Rac. Using commercial set-ups and a robust signal coupling the fluorescence excitation light and the cantilever bending, the applied force and activation signals were very easily synchronized. This approach allows to control the entire mechanical history of a single cell up to its activation and response down to a few hundreds of milliseconds, and can be extended with very minimal adaptations to other cellular systems where mechanotransduction is studied, using either purely mechanical stimuli or via a surface bound specific ligand. - Highlights: • A signal coupling AFM and fluorescence microscopy was characterized for soft cantilevers. • It can be used as an intrinsic timer to synchronize images and forces. • Mechanical stimulation of single immune cells while recording calcium fluxes was detailed. • Light-induced mechanical modifications of lymphocytes using a PA-Rac protein were demonstrated. • The precautions and limitations of use of this effect were presented.

  1. Simultaneous Laser-induced Fluorescence of Nitric Oxide and Atomic Oxygen in the Hypersonic Materials Environment Test System Arcjet Facility

    Science.gov (United States)

    Johansen, Craig; Lincoln, Daniel; Bathel, Brett; Inman, Jennifer; Danehy, Paul

    2014-01-01

    Simultaneous nitric oxide (NO) and atomic oxygen (O) laser induced fluorescence (LIF) experiments were performed in the Hypersonic Materials Environmental Test System (HYMETS) facility at the NASA Langley Research Center. The data serves as an experimental database for validation for chemical and thermal nonequilibrium models used in hypersonic flows. Measurements were taken over a wide range of stagnation enthalpies (6.7 - 18.5 MJ/kg) using an Earth atmosphere simulant with a composition of 75% N2, 20% O2, and 5% Ar (by volume). These are the first simultaneous measurements of NO and O LIF to be reported in literature for the HYMETS facility. The maximum O LIF mean signal intensity was observed at a stagnation enthalpy of approximately 12 MJ/kg while the maximum NO LIF mean signal intensity was observed at a stagnation enthalpy of 6.7 MJ/kg. Experimental results were compared to simple fluorescence model that assumes equilibrium conditions in the plenum and frozen chemistry in the isentropic nozzle expansion (Mach 5). The equilibrium calculations were performed using CANTERA v2.1.1 with 16 species. The fluorescence model captured the correlation in mean O and NO LIF signal intensities over the entire range of stagnation enthalpies tested. Very weak correlations between single-shot O and NO LIF intensities were observed in the experiments at all of the stagnation enthalpy conditions.

  2. Determination of cadmium in rice and water by tungsten coil electrothermal vaporization-atomic fluorescence spectrometry and tungsten coil electrothermal atomic absorption spectrometry after cloud point extraction

    Energy Technology Data Exchange (ETDEWEB)

    Wen Xiaodong [College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, Sichuan 610064 (China); Wu Peng [Analytical and Testing Center, Sichuan University, 29 Wangjiang Road, Chengdu, Sichuan 610064 (China); Chen Li [College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, Sichuan 610064 (China); Hou Xiandeng, E-mail: houxd@scu.edu.cn [College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, Sichuan 610064 (China); Analytical and Testing Center, Sichuan University, 29 Wangjiang Road, Chengdu, Sichuan 610064 (China)

    2009-09-14

    In this work, the microsampling nature of tungsten coil electrothermal vaporization Ar/H{sub 2} flame atomic fluorescence spectrometry (W-coil ETV-AFS) as well as tungsten coil electrothermal atomic absorption spectrometry (W-coil ET-AAS) was used with cloud point extraction (CPE) for the ultrasensitive determination of cadmium in rice and water samples. When the temperature of the extraction system is higher than the cloud point temperature of the selected surfactant Triton X-114, the complex of cadmium with dithizone can be quantitatively extracted into the surfactant-rich phase and subsequently separated from the bulk aqueous phase by centrifugation. The main factors affecting the CPE, such as concentration of Triton X-114 and dithizone, pH, equilibration temperature and incubation time, were optimized for the best extract efficiency. Under the optimal conditions, the limits of detection for cadmium by W-coil ETV-AFS and W-coil ET-AAS were 0.01 and 0.03 {mu}g L{sup -1}, with sensitivity enhancement factors of 152 and 93, respectively. The proposed methods were applied to the determination of cadmium in certified reference rice and water samples with analytical results in good agreement with certified values.

  3. Statistics of resonance fluorescence of a pair of atoms in a feedback loop

    Energy Technology Data Exchange (ETDEWEB)

    Tomilin, V. A., E-mail: 8342tomilin@mail.ru; Il' ichev, L. V. [Russian Academy of Sciences, Institute of Automatics and Electrometry, Siberian Branch (Russian Federation)

    2013-02-15

    The statistics of photoemission events of a pair of closely spaced two-level atoms is calculated in a classical light field whose phase is changed by {pi} after the detection of each spontaneous photon. This statistics is compared with the statistics in the case when the feedback is missing. In both cases, one can observe noticeable antibunching of photons in the range of parameters where no antibunching is observed in a single-atom system. The feedback substantially increases the antibunching. This effect manifests itself more strongly in relatively weak fields and for considerable frequency detunings.

  4. Computer simulations on resonant fluorescence spectra in atomic gases in two monochromatic laser fields of arbitrary intensity and magnetic field

    Science.gov (United States)

    Karagodova, Tamara Y.

    1996-03-01

    In the intense radiation fields with power density from 104W/cm2 to 109W/cm2 the essential modification of electronic states of atoms occurs displaying, in particular, in modifications of resonant fluorescence (rf) spectra. We use 'Fermi golden rule' for calculations of relative intensities and frequencies for rf multiplet for real multilevel initially unexcited atoms in two monochromatic laser fields of arbitrary intensity resonant to adjacent transitions of (Xi) or (Lambda) types and magnetic field, giving the level splittings of different values from Zeeman to Paschen-Back effect. The dependence of quasienergies on parameters obtained with the help of a sorting program permits us to define the values of parameters for which the states of the system are mixed and so to receive the correct probability amplitudes for instantaneous or adiabatic regimes of switching the perturbation. The analysis of the quasienergies and form of rf spectra permits us to get relations between the form of the spectra and modifications of electronic structure of the atom due to radiation fields and external magnetic field.

  5. Imaging magnetic scalar potentials by laser-induced fluorescence from bright and dark atoms

    CERN Document Server

    Fescenko, Ilja

    2014-01-01

    We present a spectroscopic method for mapping two-dimensional distributions of magnetic field strengths (magnetic scalar potential lines) using CCD recordings of the fluorescence patterns emitted by spin-polarized Cs vapor in a buffer gas exposed to inhomogeneous magnetic fields. The method relies on the position-selective destruction of spin polarization by magnetic resonances induced by multi-component oscillating magnetic fields, such that magnetic potential lines can directly be detected by the CCD camera. We also present a generic algebraic model allowing the calculation of the fluorescence patterns and find excellent agreement with the experimental observations for three distinct inhomogeneous field topologies. The spatial resolution obtained with these proof-of-principle experiments is on the order of 1 mm. A substantial increase of spatial and magnetic field resolution is expected by deploying the method in a magnetically shielded environment.

  6. Improving the analytical performance of hydride generation non-dispersive atomic fluorescence spectrometry. Combined effect of additives and optical filters

    Science.gov (United States)

    D'Ulivo, Alessandro; Bramanti, Emilia; Lampugnani, Leonardo; Zamboni, Roberto

    2001-10-01

    The effects of tetrahydroborate and acid concentration and the presence of L-cysteine and thiourea were investigated in the determination of As, Bi and Sn using continuous flow hydride generation atomic fluorescence spectrometry (HG AFS). The aim was to find conditions allowing the control of those effects exerting negative influence on the analytical performance of the HG AFS apparatus. The effects taken into account were: (i) the radiation scattering generated by carryover of solution from the gas-liquid separator to the atomizer; (ii) the introduction of molecular species generated by tetrahydroborate decomposition into the atomizer; and (iii) interference effects arising from other elements in the sample matrix and from different acids. The effects (i) and (ii) could be controlled using mild reaction conditions in the HG stage. The effect of HG conditions on carryover was studied by radiation scattering experiments without hydride atomization. Compromised HG conditions were found by studying the effects of tetrahydroborate (0.1-20 g l -1) and acid (0.01-7 mol l -1) concentration, and the addition of L-cysteine (10 g l -1) and thiourea (0.1 mol l -1) on the HG AFS signals. The effect of optical filters was investigated with the aim of improving the signal-to-noise ratio. Optical filters with peak wavelengths of 190 and 220 nm provided an improvement of detection limits by factors of approximately 4 and 2 for As and Te, respectively. Under optimized conditions the detection limits were 6, 5, 3, 2, 2 and 9 ng l -1 for As, Sb, Bi, Sn, Se and Te, respectively. Good tolerance to various acid compositions and sample matrices was obtained by using L-cysteine or thiourea as masking agents. Determination of arsenic in sediment and copper certified reference materials, and of bismuth in steel, sediment, soil and ore certified reference material is reported.

  7. Silver atom and strand numbers in fluorescent and dark Ag:DNAs.

    Science.gov (United States)

    Schultz, Danielle; Gwinn, Elisabeth G

    2012-06-11

    We use tandem HPLC-mass spectrometry with in-line spectroscopy to identify silver atom numbers, N(Ag), of 10 to 21 in visible- to infrared-emitting Ag:DNA complexes stabilized by oligonucleotide monomers and dimers. Qualitatively different absorbance spectra from bare, same-N(Ag) silver clusters point to silver-base interactions as the origin for the color of Ag:DNAs.

  8. 原子荧光光谱法测定土壤中的砷含量%Determination of Arsenic in Soil by Atomic Fluorescence Spectrometry

    Institute of Scientific and Technical Information of China (English)

    刘燕芬

    2015-01-01

    通过结合具体的试验对运用原子荧光光谱法测定土壤中的砷含量进行了探讨,以期能为有关方面的需要提供有益的参考和借鉴。%In order to provide a useful reference for the relevant aspects of the arsenic content in soil by atomic fluorescence spectrometry, the method of atomic fluorescence spectrometry was used to determine the arsenic content in soil.

  9. Surface passivation of nano-textured fluorescent SiC by atomic layer deposited TiO2

    DEFF Research Database (Denmark)

    Lu, Weifang; Ou, Yiyu; Jokubavicius, Valdas

    2016-01-01

    Nano-textured surfaces have played a key role in optoelectronic materials to enhance the light extraction efficiency. In this work, morphology and optical properties of nano-textured SiC covered with atomic layer deposited (ALD) TiO2 were investigated. In order to obtain a high quality surface...... for TiO2 deposition, a three-step cleaning procedure was introduced after RIE etching. The morphology of anatase TiO2 indicates that the nano-textured substrate has a much higher surface nucleated grain density than a flat substrate at the beginning of the deposition process. The corresponding...... reflectance increases with TiO2 thickness due to increased surface diffuse reflection. The passivation effect of ALD TiO2 thin film on the nano-textured fluorescent 6H-SiC sample was also investigated and a PL intensity improvement of 8.05% was obtained due to the surface passivation....

  10. Pentavalent antimony uptake pathway through erythrocyte membranes: molecular and atomic fluorescence approaches.

    Science.gov (United States)

    Barrera, Camila; López, Silvana; Aguilar, Luis; Mercado, Luis; Bravo, Manuel; Quiroz, Waldo

    2016-04-01

    Previous studies by our group have shown that Sb(V) is able to enter red blood cells in a dynamic process and is reduced to Sb(III) by glutathione. The present study aims to investigate a possible entry pathway for Sb(V) through the erythrocyte membrane. Applying fluorescence spectroscopy studies with Laurdan and diphenylhexatriene (DPH) probes, it was found that there was no interaction between Sb(V) and membrane lipids. By comparing the Sb(V) entry percentages through lipid vesicles and sealed erythrocyte membranes, it was found that Sb(V) required protein channels to pass through the membrane. The competitive inhibition results using HCO3 (-) and Cl(-) showed that the Sb(V) uptake rate through the membrane fell approximately 50-70 % until full inhibition was reached, which was possibly due to the inhibition of the anion exchanger 1 (AE1) channel. Finally, the fluorescence measurements with the 5-iodoacetamidofluorescein (5-IAF) probe showed that Sb(V) interacted with membrane protein SH groups during this process.

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

    Energy Technology Data Exchange (ETDEWEB)

    Teramoto, Yoshiyuki; Ono, Ryo [Department of Advanced Energy, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 227-8568 (Japan); Oda, Tetsuji [Department of Electrical Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2012-06-01

    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 energy 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.

  12. Atomic identification of fluorescent Q-dots on tau-positive fibrils in 3D-reconstructed pick bodies.

    Science.gov (United States)

    Uematsu, Miho; Adachi, Eijiro; Nakamura, Ayako; Tsuchiya, Kuniaki; Uchihara, Toshiki

    2012-04-01

    Pick body disease, characterized by the presence of Pick bodies, is distinguished from neurofibrillary tangles in Alzheimer disease on the basis of their smooth, spherical shape. Quantum dots (QDs) are nanometer-scale, water-soluble fluorophores that are detectable both as a fluorescent signal by light microscopy and as electron-dense particles under electron microscopy. In this study, tau-positive Pick bodies were immunofluorescently labeled with QD nanocrystals composed of cadmium selenide for three-dimensional (3D) reconstruction and subsequently subjected to electron microscopic observation to identify QD immunolabeling on the same Pick body for comparison in detail. The identity of the QD nanocrystals, which label the tau-positive fibrils, was confirmed by the presence of both cadmium and selenium on these nanocrystals, demonstrated as parallel peaks corresponding to these atoms on energy-dispersive X-ray spot analysis under super-resolution scanning transmission electron microscopy. This confirmation of the specificity of the QD labeling through both its fluorescence and energy-dispersive X-ray spectra reinforces the reliability of the labeling. In addition, this exact comparison of the same structure by electron microscopy and 3D light microscopy demonstrates how its ultrastructural details are related to its surrounding structures on a 3D basis, providing further insights into how molecules woven into specific pathological ultrastructures are at work in situ. Copyright © 2012 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  13. A new way towards high-efficiency thermally activated delayed fluorescence devices via external heavy-atom effect

    Science.gov (United States)

    Zhang, Wenzhi; Jin, Jiangjiang; Huang, Zhi; Zhuang, Shaoqing; Wang, Lei

    2016-07-01

    Thermally activated delayed fluorescence (TADF) mechanism is a significant method that enables the harvesting of both triplet and singlet excitons for emission. However, up to now most efforts have been devoted to dealing with the relation between singlet-triplet splitting (ΔEST) and fluorescence efficiency, while the significance of spin-orbit coupling (SOC) is usually ignored. In this contribution, a new method is developed to realize high-efficiency TADF-based devices through simple device-structure optimizations. By inserting an ultrathin external heavy-atom (EHA) perturber layer in a desired manner, it provides useful means of accelerating the T1 → S1 reverse intersystem crossing (RISC) in TADF molecules without affecting the corresponding S1 → T1 process heavily. Furthermore, this strategy also promotes the utilization of host triplets through Förster mechanism during host → guest energy transfer (ET) processes, which helps to get rid of the solely dependence upon Dexter mechanism. Based on this strategy, we have successfully raised the external quantum efficiency (EQE) in 4CzPN-based devices by nearly 38% in comparison to control devices. These findings provide keen insights into the role of EHA played in TADF-based devices, offering valuable guidelines for utilizing certain TADF dyes which possess high radiative transition rate but relatively inefficient RISC.

  14. Atomic force microscopy for analyzing metaphase chromosomes: comparison of AFM images with fluorescence labeling images of banding patterns.

    Science.gov (United States)

    Hoshi, Osamu; Ushiki, Tatsuo

    2014-01-01

    The combined use of fluorescence microscopy with atomic force microscopy (AFM) has been introduced to analyze the replication-banding patterns of human chromosomes. Human lymphocytes synchronized with excess thymidine are treated with 5-ethynyl-2'-deoxyuridine (EdU) during the late S phase. EdU-labeled DNA is detected in metaphase chromosomes using Alexa Fluor 488(®) azide, through the 1,3-dipolar cycloaddition reaction of organic azides with the terminal acetylene group of EdU. Chromosomes with EdU incorporated during the late S phase show a banding pattern similar to the G-banding pattern of normal human chromosomes. The comparison between the fluorescence and AFM image of the same chromosome indicates the presence of ridges and grooves in the chromatid arms, which correspond to G-positive and G-negative bands, respectively. This technique of EdU-labeled replication bands combined with AFM is useful to analyze the structure of chromosomes in relation to the banding pattern.

  15. Determination of lead in wine by hydride generation atomic fluorescence spectrometry in the presence of hexacyanoferrate(III).

    Science.gov (United States)

    Karadjova, Irina B; Lampugnani, Leonardo; D'Ulivo, Alessandro; Onor, Massimo; Tsalev, Dimiter L

    2007-06-01

    A rapid, accurate, and precise method is described for the determination of Pb in wine using continuous-flow hydride generation atomic fluorescence spectrometry (CF-HGAFS). Sample pretreatment consists of ten-fold dilution of wine followed by direct plumbane generation in the presence of 0.1 mol L(-1) HCl and 1% m/v K(3)[Fe(CN)(6)] with 1% m/v NaBH(4) as reducing agent. An aqueous standard calibration curve is recommended for Pb quantification in wine sample. The method provides a limit of detection and a limit of quantification of 0.3 microg L(-1) and 1 microg L(-1), respectively. The relative standard deviation varies between 2-6% (within-run) and 4-11% (between-run) at 3-30 microg L(-1) Pb levels in wine. Good agreement has been demonstrated between results obtained by CF-HGAFS and direct electrothermal atomic absorption spectrometry in analyses of red and white wines within the concentration range of 9.2-25.8 microg L(-1) Pb.

  16. Flow injection on-line solid phase extraction for ultra-trace lead screening with hydride generation atomic fluorescence spectrometry.

    Science.gov (United States)

    Wan, Zhuo; Xu, Zhangrun; Wang, Jianhua

    2006-01-01

    A flow injection (FI) on-line solid phase extraction (SPE) procedure for ultra-trace lead separation and preconcentration was developed, followed by hydride generation and atomic fluorescence spectrometric (AFS) detection. Lead is retained on an iminodiacetate chelating resin packed microcolumn, and is afterward eluted with 2.5% (v/v) hydrochloric acid to facilitate the hydride generation by reaction with alkaline tetrahydroborate solution with 1% (m/v) potassium ferricyanide as an oxidizing (or sensitizing) reagent. The hydride was separated from the reaction medium in the gas-liquid separator and swept into the atomizer for quantification. The chemical variables and the FI flow parameters were carefully optimized. With a sample loading volume of 4.8 ml, quantitative retention of lead was obtained, along with an enrichment factor of 11.3 and a sampling frequency of 50 h(-1). A detection limit of 4 ng l(-1), defined as 3 times the blank standard deviation (3 sigma), was achieved along with a RSD value of 1.6% at the 0.4 microg l(-1) level. The procedure was validated by determining lead contents in two certified reference materials, and its practical applicability was further demonstrated by analysing a variety of biological and environmental samples.

  17. Atomically precise arrays of fluorescent silver clusters: a modular approach for metal cluster photonics on DNA nanostructures.

    Science.gov (United States)

    Copp, Stacy M; Schultz, Danielle E; Swasey, Steven; Gwinn, Elisabeth G

    2015-03-24

    The remarkable precision that DNA scaffolds provide for arraying nanoscale optical elements enables optical phenomena that arise from interactions of metal nanoparticles, dye molecules, and quantum dots placed at nanoscale separations. However, control of ensemble optical properties has been limited by the difficulty of achieving uniform particle sizes and shapes. Ligand-stabilized metal clusters offer a route to atomically precise arrays that combine desirable attributes of both metals and molecules. Exploiting the unique advantages of the cluster regime requires techniques to realize controlled nanoscale placement of select cluster structures. Here we show that atomically monodisperse arrays of fluorescent, DNA-stabilized silver clusters can be realized on a prototypical scaffold, a DNA nanotube, with attachment sites separated by <10 nm. Cluster attachment is mediated by designed DNA linkers that enable isolation of specific clusters prior to assembly on nanotubes and preserve cluster structure and spectral purity after assembly. The modularity of this approach generalizes to silver clusters of diverse sizes and DNA scaffolds of many types. Thus, these silver cluster nano-optical elements, which themselves have colors selected by their particular DNA templating oligomer, bring unique dimensions of control and flexibility to the rapidly expanding field of nano-optics.

  18. Rocket observation of atomic oxygen and night airglow: Measurement of concentration with an improved resonance fluorescence technique

    Directory of Open Access Journals (Sweden)

    K. Kita

    Full Text Available An improved resonant fluorescence instrument for measuring atomic oxygen concentration was developed to avoid the Doppler effect and the aerodynamic shock effect due to the supersonic motion of a rocket. The shock effect is reduced by adopting a sharp wedge-shaped housing and by scanning of the detector field of view to change the distance between the scattering volume and the surface of the housing. The scanning enables us to determine absolute values of atomic oxygen concentration from relative variation of the scattered light signal due to the self-absorption. The instrument was calibrated in the laboratory, and the numerical simulation reproduced the calibration result. Using the instrument, the altitude profile of atomic oxygen concentration was observed by a rocket experiment at Uchinoura (31°N on 28 January 1992. The data obtained from the rocket experiment were not perfectly free from the shock effect, but errors due to the effect were reduced by the data analysis procedure. The observed maximum concentration was 3.8× 1011 cm–3 at altitudes around 94 km. The systematic error is estimated to be less than ±0.7×1011 cm–3 and the relative random error is less than±0.07× 1011 cm–3at the same altitudes. The altitude profile of the OI 557.7-nm airglow was also observed in the same rocket experiment. The maximum volume emission rate was found to be 150 photons cm–3 s–1 at 94 km. The observed altitude profiles are compared with the MSIS model and other in situ observations.

  19. Dielectric barrier discharges with steep voltage rise: mapping of atomic nitrogen in single filaments measured by laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Lukas, C.; Spaan, M.; Schulz-von der Gathen, V.; Thomson, M.; Wegst, R.; Döbele, H. F.; Neiger, M.

    2001-08-01

    Space and time resolved relative atomic density distributions of nitrogen have been measured for the first time at a single filament within a dielectric barrier discharge (DBD) reactor with submillimetre radial dimensions. Two-photon-Absorption Laser-Induced Fluorescence (TALIF) spectroscopy of atomic nitrogen using radiation at λ = 206.7 nm is applied to a DBD with fast rising voltage amplitudes. The decay time of the atomic nitrogen density depends strongly on the position within the discharge and the distance from the dielectric where the lifetime is maximum. Admixed oxygen leads to an increase of the N density decay by an order of magnitude even at small fractions.

  20. Measurement of total angular momentum values of high-lying even-parity atomic states of samarium by spectrally resolved laser-induced fluorescence technique

    Indian Academy of Sciences (India)

    A K Pulhani; M L Shah; G P Gupta; B M Suri

    2010-12-01

    Spectrally resolved laser-induced fluorescence technique was used to uniquely assign total angular momentum () values to high-lying even-parity energy levels of atomic samarium. Unique value assignment was done for seven energy levels in the energy region 34,800–36,200 cm-1 , recently observed and reported in the literature.

  1. An expression for the atomic fluorescence and thermal-emission intensity under conditions of near saturation and arbitrary self-absorption

    NARCIS (Netherlands)

    Omenetto, N.; Winefordner, J.D.; Alkemade, C.T.J.

    1975-01-01

    An expression for the effect of self-absorption on the fluorescence and thermal emission intensities is derived by taking into account stimulated emission. A simple, idealized case is considered, consisting of a two level atomic system, in a flame, homogeneous with respect to temperature and composi

  2. Ambient-temperature trap/release of arsenic by dielectric barrier discharge and its application to ultratrace arsenic determination in surface water followed by atomic fluorescence spectrometry

    Science.gov (United States)

    A novel dielectric barrier discharge reactor (DBDR) was utilized to trap/release arsenic coupled to hydride generation atomic fluorescence spectrometry (HGAFS). On the DBD principle, the precise and accurate control of trap/release procedures was fulfilled at ambient temperature, and an analytical m...

  3. Speciation analysis of arsenic compounds in seafood by ion chromatography-atomic fluorescence spectrometry

    Science.gov (United States)

    Han, Tingting; Ji, Hongwei; Li, Huixin; Cui, He; Song, Tian; Duan, Xiaojuan; Zhu, Qianlin; Cai, Feng; Zhang, Li

    2017-06-01

    Ion chromatography-ultra violet-hydride generation-Atomic Florescence Spectrometry was applied to detect 5 arsenic species in seafoods. The arsenic species studied include arsenobetaine (AsB), arsenite (As(III)), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA), and arsenate (As(V)), which were extracted from samples using 2% formic acid. Gradient elution using 33 mmol L-1 CH3COONH4 and 15 mmol L-1 Na2CO3 with 10 mL CH3CH2OH at pH 8.4 allowed the chromatographic separation of all the species on a Hamilton PRP-X100 anion-exchange column in less than 8 min. In this study, an ultrasound extraction method was used to extract arsenic species from seafood. The extraction efficiency was good and the recoveries from spiked samples were in the range of 72.6%-109%; the precision between sample replicates was higher than 3.6% for all determinations. The detection limits were 3.543 μg L-1 for AsB, 0.426 μg L-1 for As(III), 0.216 μg L-1 for DMA, 0.211 μg L-1 for MMA, and 0.709 μg L-1 for As(V), and the linear coefficients were greater than 0.999. We also developed an application of this method for the determination of arsenic species in bonito, Euphausia superba, and Enteromorpha with satisfactory results. Therefore, it was confirmed that this method was appropriate for the detection of arsenic species in seafood.

  4. Liquid film thickness measurement by two-line TDLAS

    Science.gov (United States)

    Yang, Huinan; Chen, Jun; Cai, Xiaoshu; Greszik, Daniel; Dreier, Thomas; Schulz, Christof

    2014-04-01

    A fiber-based two-line tunable diode-laser absorption sensor with two near-infrared (NIR) distributed-feedback (DFB) diode lasers at ˜1.4 μm was used for non-intrusive time-resolved liquid water film thickness measurement. When probing the liquid film at two different wavelengths with significantly different absorption cross-sections, the additional signal losses due to surface fowling, reflection and beam steering can be eliminated. In this work, the evaporation process of a liquid film on transparent quartz plate was tracked and large fluctuations of film thickness were found at the end of the evaporation.

  5. Liquid film thickness measurement by two-line TDLAS

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Huinan [School of Energy and Power Engineering, University of Shanghai for Science and Technology, 200093, Shanghai, China and IVG, University of Duisburg-Essen, 47057, Duisburg (Germany); Chen, Jun; Cai, Xiaoshu [School of Energy and Power Engineering, University of Shanghai for Science and Technology, 200093, Shanghai (China); Greszik, Daniel; Dreier, Thomas; Schulz, Christof [IVG, University of Duisburg-Essen, 47057, Duisburg (Germany)

    2014-04-11

    A fiber-based two-line tunable diode-laser absorption sensor with two near-infrared (NIR) distributed-feedback (DFB) diode lasers at ∼1.4 μm was used for non-intrusive time-resolved liquid water film thickness measurement. When probing the liquid film at two different wavelengths with significantly different absorption cross-sections, the additional signal losses due to surface fowling, reflection and beam steering can be eliminated. In this work, the evaporation process of a liquid film on transparent quartz plate was tracked and large fluctuations of film thickness were found at the end of the evaporation.

  6. Development of an analytical method for antimony speciation in vegetables by HPLC-hydride generation-atomic fluorescence spectrometry.

    Science.gov (United States)

    Olivares, David; Bravo, Manuel; Feldmann, Jorg; Raab, Andrea; Neaman, Alexander; Quiroz, Waldo

    2012-01-01

    A new method for antimony speciation in terrestrial edible vegetables (spinach, onions, and carrots) was developed using HPLC with hydride generation-atomic fluorescence spectrometry. Mechanical agitation and ultrasound were tested as extraction techniques. Different extraction reagents were evaluated and optimal conditions were determined using experimental design methodology, where EDTA (10 mmol/L, pH 2.5) was selected because this chelate solution produced the highest extraction yield and exhibited the best compatibility with the mobile phase. The results demonstrated that EDTA prevents oxidation of Sb(III) to Sb(V) and maintains the stability of antimony species during the entire analytical process. The LOD and precision (RSD values obtained) for Sb(V), Sb(III), and trimethyl Sb(V) were 0.08, 0.07, and 0.9 microg/L and 5.0, 5.2, and 4.7%, respectively, for a 100 microL sample volume. The application of this method to real samples allowed extraction of 50% of total antimony content from spinach, while antimony extracted from carrots and onion samples ranged between 50 and 60 and 54 and 70%, respectively. Only Sb(V) was detected in three roots (onion and spinach) that represented 60-70% of the total antimony in the extracts.

  7. Determination of lead in environmental waters with dispersive liquid-liquid microextraction prior to atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Qingxiang, E-mail: zhouqx@cup.edu.cn [School of Chemistry and Environmental Sciences, Henan Normal University, Henan Key Laboratory for Environmental Pollution Control, Key Laboratory for Yellow River and Huaihe River Water Environment and Pollution Control, Ministry of Education, Xinxiang 453007 (China); State Laboratory of Petroleum Resource and Prospecting, College of Geosciences, China University of Petroleum Beijing, Beijing 102249 (China); Zhao, Na [State Laboratory of Petroleum Resource and Prospecting, College of Geosciences, China University of Petroleum Beijing, Beijing 102249 (China); Xie, Guohong [College of Resources and Environment, Henan Institute of Science and Technology, Xinxiang 453003 (China)

    2011-05-15

    This paper established a new, rapid and sensitive method for the determination of lead in water samples preconcentrated by dispersive liquid-liquid microextraction (DLLME) prior to atomic fluorescence spectrometry. Dithizone was used as the chelating agent. In the DLLME procedure, lead formed lead-dithizone complex and migrated into the carbon tetrachloride micro-droplets. Important factors that would affect the extraction efficiency had been investigated including the kind and volume of extraction solvent and dispersive solvent, sample pH, the amount of chelating agent, extraction time and centrifugation time. The results showed that the coexisting ions containing in water samples had no obvious negative effect on the determination of lead. The experimental results indicated that the proposed method had a good linear range of 0.01-100 ng mL{sup -1} (r{sup 2} = 0.9990). The precision was 2.12% (RSD, n = 7) and the detection limit was 0.95 ng L{sup -1}. Proposed method was validated with four real environmental samples and the results indicated that the proposed method was excellent for the future use and satisfied spiked recoveries were in the range of 92.9-97.4%.

  8. Antimony speciation analysis in sediment reference materials using high-performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Potin-Gautier, M. [Laboratoire de Chimie Analytique, BioInorganique et Environnement LCABIE (UMR CNRS 3054), Universite de Pau et des pays de l' Adour, 64000 Pau (France); Pannier, F. [Laboratoire de Chimie Analytique, BioInorganique et Environnement LCABIE (UMR CNRS 3054), Universite de Pau et des pays de l' Adour, 64000 Pau (France)]. E-mail: Florence.pannier@univ-pau.fr; Quiroz, W. [Laboratoire de Chimie Analytique, BioInorganique et Environnement LCABIE (UMR CNRS 3054), Universite de Pau et des pays de l' Adour, 64000 Pau (France); Laboratorio de Quimica Analitica y Ambiental, Instituto de Quimica, Pontificia Universidad catolica de Valparaiso (Chile); Pinochet, H. [Laboratorio de Quimica Analitica y Ambiental, Instituto de Quimica, Pontificia Universidad catolica de Valparaiso (Chile); Gregori, I. de [Laboratorio de Quimica Analitica y Ambiental, Instituto de Quimica, Pontificia Universidad catolica de Valparaiso (Chile)

    2005-11-30

    This work presents the development of suitable methodologies for determination of the speciation of antimony in sediment reference samples. Liquid chromatography with a post-column photo-oxidation step and hydride generation atomic fluorescence spectrometry as detection system is applied to the separation and determination of Sb(III), Sb(V) and trimethylantimony species. Post-column decomposition and hydride generation steps were studied for sensitive detection with the AFS detector. This method was applied to investigate the conditions under which speciation analysis of antimony in sediment samples can be carried out. Stability studies of Sb species during the extraction processes of solid matrices, using different reagents solutions, were performed. Results demonstrate that for the extraction yield and the stability of Sb species in different marine sediment extracts, citric acid in ascorbic acid medium was the best extracting solution for antimony speciation analysis in this matrix (between 55% and 65% of total Sb was recovered from CRMs, Sb(III) being the predominant species). The developed method allows the separation of the three compounds within 6 min with detection limits of 30 ng g{sup -1} for Sb(III) and TMSbCl2 and 40 ng g{sup -1} for Sb(V) in sediment samples.

  9. High-resolution elasticity maps and cytoskeletal dynamics of neurons measured by combined fluorescence and atomic force microscopy

    Science.gov (United States)

    Staii, Cristian

    2014-03-01

    Detailed knowledge of mechanical parameters such as cell elasticity, stiffness of the growth substrate, or traction stresses generated during axonal extensions is essential for understanding the mechanisms that control neuronal growth. Here I present results obtained in my research group, which combine Atomic Force Microscopy and Fluorescence Microscopy measurements to produce systematic, high-resolution elasticity maps for different types of live neuronal cells cultured on glass or biopolymer-based substrates. We measure how the stiffness of neurons changes both during neurite outgrowth and upon chemical modification (disruption of the cytoskeleton) of the cell. We find a reversible local stiffening of the cell during growth, and show that the increase in local elastic modulus is primarily due to the formation of microtubules in the cell soma. We also report a reversible shift in the elastic modulus of the cortical neurons cytoskeleton with temperature, from tubulin dominated regions at 37C to actin dominated regions at 25C. We demonstrate that the dominant mechanism by which the elasticity of the neuronal soma changes in response to temperature is the contractile stiffening of the actin component of the cytoskeleton induced by the activity of myosin II motors. We acknowledge financial support from NSF grant CBET 1067093.

  10. Cloud point extraction for trace inorganic arsenic speciation analysis in water samples by hydride generation atomic fluorescence spectrometry

    Science.gov (United States)

    Li, Shan; Wang, Mei; Zhong, Yizhou; Zhang, Zehua; Yang, Bingyi

    2015-09-01

    A new cloud point extraction technique was established and used for the determination of trace inorganic arsenic species in water samples combined with hydride generation atomic fluorescence spectrometry (HGAFS). As(III) and As(V) were complexed with ammonium pyrrolidinedithiocarbamate and molybdate, respectively. The complexes were quantitatively extracted with the non-ionic surfactant (Triton X-114) by centrifugation. After addition of antifoam, the surfactant-rich phase containing As(III) was diluted with 5% HCl for HGAFS determination. For As(V) determination, 50% HCl was added to the surfactant-rich phase, and the mixture was placed in an ultrasonic bath at 70 °C for 30 min. As(V) was reduced to As(III) with thiourea-ascorbic acid solution, followed by HGAFS. Under the optimum conditions, limits of detection of 0.009 and 0.012 μg/L were obtained for As(III) and As(V), respectively. Concentration factors of 9.3 and 7.9, respectively, were obtained for a 50 mL sample. The precisions were 2.1% for As(III) and 2.3% for As(V). The proposed method was successfully used for the determination of trace As(III) and As(V) in water samples, with satisfactory recoveries.

  11. Two-photon absorption laser induced fluorescence measurement of atomic oxygen density in an air atmospheric pressure plasma jet

    Science.gov (United States)

    Conway, Jim; Gogna, Gurusharan; Daniels, Stephen

    2016-09-01

    Two-photon Absorption Laser Induced Fluorescence (TALIF) is used to measure atomic oxygen number density [O] in an air Atmospheric Pressure Plasma Jet (APPJ). A novel technique based on photolysis of O2 is used to calibrate the TALIF system ensuring the same species (O) is probed during calibration and measurement. As a result, laser intensity can be increased outside the TALIF quadratic laser power region without affecting calibration reliability as any high intensity saturation effects will be identical for calibration and experiment. Higher laser intensity gives stronger TALIF signals helping overcome weak TALIF signals often experienced at atmospheric pressure due to collisional quenching. O2 photo-dissociation and two-photon excitation of the resulting [O] are both achieved within the same laser pulse. The photolysis [O] is spatially non-uniform and time varying. To allow valid comparison with [O] in a plasma, spatial and temporal correction factors are required. Knowledge of the laser pulse intensity I0(t), and wavelength allows correction factors to be found using a rate equation model. The air flow into the jet was fixed and the RF power coupled into the system varied. The resulting [O] was found to increase with RF power.

  12. Stratum corneum lipid organization as observed by atomic force, confocal and two-photon excitation fluorescence microscopy.

    Science.gov (United States)

    Norlén, L; Plasencia, I; Bagatolli, L

    2008-12-01

    Skin moisturization is largely a function of stratum corneum barrier capacity, which in turn is a function of the physical state and structural organization of the stratum corneum extracellular lipid matrix [J. Invest. Dermatol.18, 433 (1952); AIChE J. 21, 985 (1975); Acta Derm. Venereol.74, 1 (1994); J. Invest. Dermatol.117, 830 (2001)]. Three unsolved key questions with respect to this lipid matrix' structural organization [Acta Derm. Venereol.74, 1 (1994); J. Invest. Dermatol.117, 830 (2001); J. Invest. Dermatol.118, 897 (2002); J. Invest. Dermatol.118, 899 (2002)] are: i) whether the lipid matrix is constituted by a single-gel phase or by co-existing solid (crystalline or gel) domains, ii) whether a separate fluid (liquid crystalline) phase is present and iii) whether the local pH has a direct effect on the lipid matrix' phase behaviour. Using an array of complementary visual-related biophysical techniques (e.g. atomic force microscopy and confocal/two-photon excitation fluorescence microscopy), it was recently shown that reconstituted membranes composed of extracted decontaminated human stratum corneum lipids do not form a fluid phase, but exclusively a single-gel phase that segregates into co-existing microscopic domains below pH 6 [Biophys. J.93, 3142 (2007)]. It was further shown that the role of cholesterol is related to dispersion of ceramide-enriched domains. This effect is counteracted by the presence of free fatty acids, which mix with skin ceramides but not with cholesterol.

  13. Determination of arsenic speciation in sulfidic waters by Ion Chromatography Hydride-Generation Atomic Fluorescence Spectrometry (IC-HG-AFS).

    Science.gov (United States)

    Keller, Nicole S; Stefánsson, Andri; Sigfússon, Bergur

    2014-10-01

    A method for the analysis of arsenic species in aqueous sulfide samples is presented. The method uses an ion chromatography system connected with a Hydride-Generation Atomic Fluorescence Spectrometer (IC-HG-AFS). With this method inorganic As(III) and As(V) species in water samples can be analyzed, including arsenite (HnAs(III)O3(n-3)), thioarsenite (HnAs(III)S3(n-3)), arsenate (HnAs(V)O4(n-3)), monothioarsenate (HnAs(V)SO3(n-3)), dithioarsenate (HnAs(V)S2O2(n-3)), trithioarsenate (HnAs(V)S3O(n-3)) and tetrathioarsenate (HnAs(V)S4(n-3)). The peak identification and retention times were determined based on standard analysis of the various arsenic compounds. The analytical detection limit was ~1-3 µg L(-1) (LOD), depending on the quality of the baseline. This low detection limit makes this method also applicable to discriminate between waters meeting the drinking water standard of max. 10 µg L(-1) As, and waters that do not meet this standard. The new method was successfully applied for on-site determination of arsenic species in natural sulfidic waters, in which seven species were unambiguously identified.

  14. Improved orbit predictions using two-line elements

    CERN Document Server

    Levit, Creon

    2010-01-01

    The density of orbital space debris constitutes an increasing environmental challenge. There are three ways to alleviate the problem: debris mitigation, debris removal and collision avoidance. This paper addresses collision avoidance, by describing a method that contributes to achieving a requisite increase in orbit prediction accuracy. Batch least-squares differential correction is applied to the publicly available two-line element (TLE) catalog of space objects. Using a high-precision numerical propagator, we fit an orbit to state vectors derived from successive TLEs. We then propagate the fitted orbit further forward in time. These predictions are compared to precision ephemeris data derived from the International Laser Ranging Service (ILRS) for several satellites, including objects in the congested sun-synchronous orbital region. The method leads to a predicted range error that increases at a typical rate of 100 meters per day, approximately a 10-fold improvement over TLE's propagated with their associat...

  15. Determination of trace selenium in high purity tellurium by hydride generation atomic fluorescence spectrometry after solid phase extraction of a diaminobenzidine-selenium chelate

    Science.gov (United States)

    Tong, Wang; Ying, Zeng; Jinyong, Xu

    2016-09-01

    Macroporous adsorption resin was used as the sorbent for solid phase extraction and determination of the trace Se content in high purity tellurium prior to hydride generation atomic fluorescence spectrometry analysis. Selenium was converted into an organic Se chelate using 3,3‧-diaminobenzidine and was separated from the tellurium matrix by solid phase extraction. The resin was packed as a column for solid phase extraction. Under optimum conditions, trace Se can be quantitatively extracted and the tellurium matrix can be removed. The Se in the eluate was determined by hydride generation atomic fluorescence spectrometry. The limit of detection (3σ) of this method was 0.22 ng g- 1 and the relative standard deviation (RSD, n = 5) ranged from 2.0 to 2.5% for the three investigated tellurium samples. The proposed method was successfully applied for the determination of the trace Se content in high purity tellurium samples.

  16. Simultaneous determination of p-arsanilic acid and roxarsone in feed by liquid chromatography-hydride generation online coupled with atomic fluorescence spectrometry.

    Science.gov (United States)

    Liu, Jianjing; Yu, Hongxia; Song, Haibin; Qiu, Jing; Sun, Fengmei; Li, Ping; Yang, Shuming

    2008-08-01

    A novel, simple and sensitive liquid chromatography-hydride generation online coupled with atomic fluorescence spectrometry (LC-HG-AFS) method was developed for simultaneous determination of p-arsanilic acid (p-ASA) and roxarsone in feed. 20% Methanol aqueous was used as extraction reagent, after preprocessing samples by ultrasonic oscillation, then injected into the chromatography Waters symmetry shield RP18 analytical column (150mm x 4.6mm, 5 microm), finally detected by an atomic fluorescence spectrometer. The calibration curves of analyses were linear over a range of concentrations (0.2-4mg L-1 and the correlation coefficients were higher than 0.9990. The limits of detection were 0.2 mg L-1. The method has been validated by linearity, precision and recovery. p-ASA and roxarsone in feed can be successfully and simultaneously determined using the developed method without a tedious pretreatment procedure.

  17. Polymorphism of Two-Dimensional Cyanine Dye J-Aggregates and Its Genesis: Fluorescence Microscopy and Atomic Force Microscopy Study.

    Science.gov (United States)

    Prokhorov, Valery V; Perelygina, Olga M; Pozin, Sergey I; Mal'tsev, Eugene I; Vannikov, Anatoly V

    2015-12-01

    Polymorphic J-aggregates of monomethine cyanine dye 3,3'-di(γ-sulfopropyl)-5,5'-dichlorotiamonomethinecyanine (TC) have been studied by fluorescence optical microscopy (FOM) and by atomic force microscopy (AFM). The in situ FOM observations in a solution drop distinguish two J-aggregate morphology classes: flexible strips and rigid rods. The AFM imaging of dried samples reveals a strong J-aggregate structural rearrangement under adsorption on a mica surface with the strips self-folding and the rods squashing into rectangular bilayers and much deeper destruction. In the present work, the following structural conclusions have been drawn on the basis of careful consideration of strip crystal habits and various structural features of squashed/destructed rods: (1) the tubular morphology of TC rods is directly proved by FOM measurements in the solution bulk; (2) the staircase model of molecular arrangement in strips is proposed explaining the characteristic ∼44° skew angle in strip vertices; (3) a model of tube formation by a close-packed helical winding of flexible monolayer strips is proposed and justified which explains the observed J-aggregate polymorphism and strip-to-rod polymorphic transformations in a wide spatiotemporal scale; (4) at a nanoscale, an unexpectedly complex quasi-one-dimensional organization in J-aggregate two-dimensional monolayers is observed by high-resolution AFM imaging of constituent nanostrips separated by a characteristic distance in the range of 6-10 nm. The obtained results indicate that the underlying monolayer structure is the same for all J-aggregate polymorphs.

  18. Cloud point extraction for trace inorganic arsenic speciation analysis in water samples by hydride generation atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shan, E-mail: ls_tuzi@163.com; Wang, Mei, E-mail: wmei02@163.com; Zhong, Yizhou, E-mail: yizhz@21cn.com; Zhang, Zehua, E-mail: kazuki.0101@aliyun.com; Yang, Bingyi, E-mail: e_yby@163.com

    2015-09-01

    A new cloud point extraction technique was established and used for the determination of trace inorganic arsenic species in water samples combined with hydride generation atomic fluorescence spectrometry (HGAFS). As(III) and As(V) were complexed with ammonium pyrrolidinedithiocarbamate and molybdate, respectively. The complexes were quantitatively extracted with the non-ionic surfactant (Triton X-114) by centrifugation. After addition of antifoam, the surfactant-rich phase containing As(III) was diluted with 5% HCl for HGAFS determination. For As(V) determination, 50% HCl was added to the surfactant-rich phase, and the mixture was placed in an ultrasonic bath at 70 °C for 30 min. As(V) was reduced to As(III) with thiourea–ascorbic acid solution, followed by HGAFS. Under the optimum conditions, limits of detection of 0.009 and 0.012 μg/L were obtained for As(III) and As(V), respectively. Concentration factors of 9.3 and 7.9, respectively, were obtained for a 50 mL sample. The precisions were 2.1% for As(III) and 2.3% for As(V). The proposed method was successfully used for the determination of trace As(III) and As(V) in water samples, with satisfactory recoveries. - Highlights: • Cloud point extraction was firstly established to determine trace inorganic arsenic(As) species combining with HGAFS. • Separate As(III) and As(V) determinations improve the accuracy. • Ultrasonic release of complexed As(V) enables complete As(V) reduction to As(III). • Direct HGAFS analysis can be performed.

  19. Continuous Determination of Heavy Metals in Water by Atomic Fluorescence and Atomic Absorption Spectrometry%原子荧光和原子吸收法连续测定水中的重金属

    Institute of Scientific and Technical Information of China (English)

    谢倩

    2015-01-01

    通过剖析原子荧光和原子吸收法的不同消解体系,优化实验条件,确定了原子荧光和原子吸收法连续测定水中的硒、砷、锌、铜的含量的最佳消解条件和最佳仪器测定条件。经加标回收以及标样分析,连续测定的灵敏度高,回收率在95.9%~109%之间,相对标准误差低于4.41%,操作简便快速,结果精确。%By analyzing the different digestion system of atomic fluorescence and atomic absorption method and optimizing experimental conditions, the optimal digestion conditions and the best measurement conditions of instruments for continuous determination selenium, arsenic, zinc, copper content in water by atomic fluorescence and atomic absorption spectrometry were determined.Spiking recovery and standard analysis result showed that continuous measurement had high sensitivity, and the recoveries was between 95.9% and 109%, relative standard deviation was less than 4.41%, the operation was simple, rapid and accurate.

  20. Total Mercury Determination in Petroleum Green Coke and Oily Sludge Samples by Cold Vapor Atomic Fluorescence Spectrometry

    National Research Council Canada - National Science Library

    Camera, Adriana S; Maranhão, Tatiane A; Oliveira, Fernando J. S; Silva, Jessee S. A; Frescura, Vera L. A

    2015-01-01

    ...+ before the atomic vapor formation. Accuracy of the method was evaluated through certified reference material, for green coke, and comparison with cold vapor atomic absorption spectrometry (CV AAS), for oily sludge...

  1. The estimation of the possibilities of synchrotron radiation X-ray fluorescent analysis and atomic specrometry for the bone's elemental composition determination

    Science.gov (United States)

    Gonchar, A. M.; Kolmogorov, U. P.; Gladkikh, E. A.; Shuvaeva, O. V.; Beisel, N. F.; Kolosova, N. G.

    2005-05-01

    Possibilities of multielemental highly sensitive techniques of analysis have been studied: synchrotron radiation X-ray fluorescence analysis (SR XFA), and atomic emission spectrometry with inductively bound plasma (ISP) and atomic absorption spectrometry (AAS) with flame (air-acetylene) atomization for assay of element composition of bone tissue with minimal preparation procedure. Results of comparative studies of elemental composition of bone tissue samples from experimental animals with inherited accelerated aging (rats of OXYS strain) using the SR XFA, ISP and AAS techniques are presented. It is shown that there exists in principle a possibility of assay of 22 biologically important essential macro- and trace elements within the range of 1.0-100,000 μg/g with a mean square analysis error of no more them 10-15% when using SR XFA.

  2. Non-dispersive atomic-fluorescence spectrometry of trace amounts of bismuth by introduction of its gaseous hydride into a premixed argon (entrained air)-hydrogen flame.

    Science.gov (United States)

    Kobayashi, S; Nakahara, T; Musha, S

    1979-10-01

    A method has been developed for the determination of bismuth by generation of its gaseous hydride and introduction of the hydride into a premixed argon (entrained air)-hydrogen flame, the atomic-fluorescence lines from which are all detected by use of a non-dispersive system. The detection limit is 5 pg/ml, or 0.1 ng of bismuth, but the reagent blank found in a 20-ml sample volume was approximately 2 ng of bismuth. Analytical working curves obtained by measuring peak-heights and integrated peak-areas of the signals are linear over a range of about four orders of magnitude from the detection limit. Perchloric, phosphoric and sulphuric acids up to 2.0M concentration give no interference, but nitric acid gives slight depression of the signal. The presence of silver, gold, nickel, palladium, platinum, selenium and tellurium in 1000-fold ratio to bismuth causes pronounced depression of the signal, whereas mercury and tin slightly enhance the atomic-fluorescence signal. The method has been applied to the determination of bismuth in aluminium-base alloys and sulphide ores with use of the standard additions method. The results are in good agreement with those obtained by flame atomic-absorption spectrometry and optical emission spectrometry with an inductively coupled plasma.

  3. Measurement of radiative lifetime in atomic samarium using simultaneous detection of laser-induced fluorescence and photoionization signals

    Indian Academy of Sciences (India)

    A C Sahoo; M L Shah; P K Mandal; A K Pulhani; G P Gupta; Vas Dev; B M Suri

    2014-02-01

    In this paper, we report the investigations of lifetime measurement of odd-parity energy level 19009.52 cm-1 of Sm I using simultaneous detection of laser-induced fluorescence and laserinduced photoionization signals employing pump–probe technique. To the best of our knowledge, this is for the first time that the results obtained using laser-induced fluorescence and photoionization techniques have been compared with each other. The obtained results match well with those reported in the literature.

  4. Measurement of K-X-rays fluorescence cross-sections, fluorescence yields and intensity ratios for elements in the atomic range 21 < Z < 74 excited by 59 keV photons

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Avila, J.; Lopez-Pino, N.; Padilla-Cabal, F.; Van Espen, P.; Cabal, A.; Pena, M. Ruiz; Alessandro, K.D.; Maidana, N.L. [Instituto Superior de Tecnologia y Ciencias Aplicadas (InSTEC), La Habana (Cuba); Antwerp Univ. (Belgium). Micro Trace Analytical Center; CEADEN, La Habana (Cuba); Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Lab. do Acelerador Linear

    2010-07-01

    Full text: Using 59 keV photons, we measured the K{sub {alpha}}, K{sub {beta}} and total K X-rays fluorescence cross sections of 17 elements in the atomic range 21 < Z < 74. Furthermore, the fluorescence yields and the I{sub K{beta}} / I{sub K{alpha}} intensity ratios for these elements were also determined. An annular radioactive source of {sup 241}Am (activity 1 Ci) was employed to excite the elements in targets with the shape of foils or pellets (99% purity and 20 mm, in diameter). The pellets were formed with a mixture of cellulose and a chemical compound containing the element of interest, pressed at 15 tons. The K X-rays emitted from the irradiated samples were detected by a Si(Li) detector with a frontal Pb collimator, coupled to conventional electronics, with dead time below 10%. The fluxes reaching the targets and the crystal detector were determined by means of Monte Carlo (MC) simulations using the MCNPX V 2.6 code. The input geometries included the detector, the sample-source holder and the Pb collimator. The optimal diameter for the samples as well as the collimator dimensions were estimated by means of MC simulations. Using several elements (Ti, Ni, Br, Ag, Cs, Dy and W) a calibration curve for the effective flux of photons (I{sub 0}G{sub {epsilon}}) as function of the K X-rays energy was measured. Correction by different sizes and self-absorption coefficients of the samples were also performed. The data obtained for the X-rays fluorescence cross sections were compared with semi-empirical calculations and with experimental values reported by other authors; the relative deviations were less than 10%. Keywords: fluorescence cross section, fluorescence yields, Monte Carlo (author)

  5. Density relaxation and particle motion characteristics in a non-ionic deep eutectic solvent (acetamide + urea): Time-resolved fluorescence measurements and all-atom molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Das, Anuradha; Das, Suman; Biswas, Ranjit, E-mail: ranjit@bose.res.in [Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata, West Bengal 700098 (India)

    2015-01-21

    Temperature dependent relaxation dynamics, particle motion characteristics, and heterogeneity aspects of deep eutectic solvents (DESs) made of acetamide (CH{sub 3}CONH{sub 2}) and urea (NH{sub 2}CONH{sub 2}) have been investigated by employing time-resolved fluorescence measurements and all-atom molecular dynamics simulations. Three different compositions (f) for the mixture [fCH{sub 3}CONH{sub 2} + (1 − f)NH{sub 2}CONH{sub 2}] have been studied in a temperature range of 328-353 K which is ∼120-145 K above the measured glass transition temperatures (∼207 K) of these DESs but much lower than the individual melting temperature of either of the constituents. Steady state fluorescence emission measurements using probe solutes with sharply different lifetimes do not indicate any dependence on excitation wavelength in these metastable molten systems. Time-resolved fluorescence anisotropy measurements reveal near-hydrodynamic coupling between medium viscosity and rotation of a dissolved dipolar solute. Stokes shift dynamics have been found to be too fast to be detected by the time-resolution (∼70 ps) employed, suggesting extremely rapid medium polarization relaxation. All-atom simulations reveal Gaussian distribution for particle displacements and van Hove correlations, and significant overlap between non-Gaussian (α{sub 2}) and new non-Gaussian (γ) heterogeneity parameters. In addition, no stretched exponential relaxations have been detected in the simulated wavenumber dependent acetamide dynamic structure factors. All these results are in sharp contrast to earlier observations for ionic deep eutectics with acetamide [Guchhait et al., J. Chem. Phys. 140, 104514 (2014)] and suggest a fundamental difference in interaction and dynamics between ionic and non-ionic deep eutectic solvent systems.

  6. High-resolution multiphoton laser-induced fluorescence spectroscopy of zinc atoms ejected from laser-irradiated ZnS crystals

    Science.gov (United States)

    Arlinghaus, H. F.; Calaway, W. F.; Young, C. E.; Pellin, M. J.; Gruen, D. M.; Chase, L. L.

    1989-01-01

    Time-of-flight (TOF) measurements employing high-resolution multiphoton laser-induced fluorescence spectroscopy (LFS) have been used as a probe to determine the yield and velocity distributions of Zn atoms ejected from a ZnS single crystal under irradiation by 308-nm photons. For fluences between 20 and 80 mJ/cm2 (irradiated area 2 mm2), the velocity distributions could be fitted by Maxwell-Boltzmann distributions where the characteristic temperature increased from 2000 to 9000 K, respectively. The absolute neutral Zn yield also increased from 108 to 1012 atoms per pulse over this same fluence range. Plots of temperature (T) as a function of fluence (F) and yield as a function of 1/T and 1/F suggest thermal evaporation as the mechanism for the Zn emission.The results indicate that with increasing fluence a critical combination of particle density and laser intensity is reached for formation of a plasma which interacts with the surface to cause catastrophic failure. For consecutive laser shots at constant ablation laser fluences, a nearly exponential increase of the Zn particle density was observed, although the measured kinetic temperature remains approximately constant even beyond the onset of visible damage to the ZnS surface. Doppler-shift techniques have been combined with TOF measurements for the first time in order to separate prompt from delayed emission of ablated atoms as well as to probe possible molecular or cluster ejection and fragmentation. Evidence for the latter phenomena was obtained.

  7. Ultra-narrow spectroscopic cells in atomic spectroscopy: reflection, transmission, fluorescence, and nonadiabatic transitions at the walls

    Science.gov (United States)

    Pazgalev, A.; Sarkisyan, D.; Cartaleva, S.; Przhibelskii, S.; Vartanyan, T.

    2014-11-01

    Ultra-narrow cells with the thicknesses in the range from several wavelengths to the small fractions of the wavelength brought a number of new opportunities for atomic spectroscopy. Depending on the cell thickness, spectral lines recorded in ultra-narrow cells are either Doppler-free or Doppler-broadened. With careful selection of the cell thickness hyperfine structure may be easily resolved without resorting on the multibeam nonlinear optical techniques. Moreover, frequent collisions with the walls leads to the important modifications of velocity selective optical pumping resonances. Finally, ultra-narrow cells provide with the unique opportunity to study collisions of the excited atoms with the solid surfaces. In this contribution several examples of the use of the ultra-narrow spectroscopic cells filled with the alkali atomic vapour is presented. First, we discuss general aspects of the transient polarisation that defines all peculiarities of an ultra-narrow cell as a spectroscopic tool. Second, we demonstrate the resolution of the magnetic sublevels in the transition from Zeeman to Paschen-Back regime in the Cs hyperfine structure. Third, new aspects of velocity selective optical pumping resonances in reflection and transmission of resonant radiation by the 6 wavelengths thick cell filled with Cs are discussed. Forth, the experimental evidences of the nonadiabatic transitions between excited states of Rb atoms in the course of collisions with the sapphire surface are presented.

  8. Comparison of nanosecond and picosecond excitation for interference-free two-photon laser-induced fluorescence detection of atomic hydrogen in flames.

    Science.gov (United States)

    Kulatilaka, Waruna D; Patterson, Brian D; Frank, Jonathan H; Settersten, Thomas B

    2008-09-10

    Two-photon laser-induced fluorescence (TP-LIF) line imaging of atomic hydrogen was investigated in a series of premixed CH4/O2/N2, H2/O2, and H2/O2/N2 flames using excitation with either picosecond or nanosecond pulsed lasers operating at 205 nm. Radial TP-LIF profiles were measured for a range of pulse fluences to determine the maximum interference-free signal levels and the corresponding picosecond and nanosecond laser fluences in each of 12 flames. For an interference-free measurement, the shape of the TP-LIF profile is independent of laser fluence. For larger fluences, distortions in the profile are attributed to photodissociation of H2O, CH3, and/or other combustion intermediates, and stimulated emission. In comparison with the nanosecond laser, excitation with the picosecond laser can effectively reduce the photolytic interference and produces approximately an order of magnitude larger interference-free signal in CH4/O2/N2 flames with equivalence ratios in the range of 0.5laser fluence in all flames, stimulated emission, occurring between the laser-excited level, H(n=3), and H(n=2), is the limiting factor for picosecond excitation in the flames with the highest H atom concentration. Nanosecond excitation is advantageous in the richest (Phi=1.64) CH4/O2/N2 flame and in H2/O2/N2 flames. The optimal excitation pulse width for interference-free H atom detection depends on the relative concentrations of hydrogen atoms and photolytic precursors, the flame temperature, and the laser path length within the flame.

  9. Diagnostics of Carbon Nanotube Formation in a Laser Produced Plume: An Investigation of the Metal Catalyst by Laser Ablation Atomic Fluorescence Spectroscopy

    Science.gov (United States)

    deBoer, Gary; Scott, Carl

    2003-01-01

    Carbon nanotubes, elongated molecular tubes with diameters of nanometers and lengths in microns, hold great promise for material science. Hopes for super strong light-weight material to be used in spacecraft design is the driving force behind nanotube work at JSC. The molecular nature of these materials requires the appropriate tools for investigation of their structure, properties, and formation. The mechanism of nanotube formation is of particular interest because it may hold keys to controlling the formation of different types of nanotubes and allow them to be produced in much greater quantities at less cost than is currently available. This summer's work involved the interpretation of data taken last summer and analyzed over the academic year. The work involved diagnostic studies of carbon nanotube formation processes occurring in a laser-produced plume. Laser ablation of metal doped graphite to produce a plasma plume in which carbon nanotubes self assemble is one method of making carbon nanotube. The laser ablation method is amenable to applying the techniques of laser spectroscopy, a powerful tool for probing the energies and dynamics of atomic and molecular species. The experimental work performed last summer involved probing one of the metal catalysts, nickel, by laser induced fluorescence. The nickel atom was studied as a function of oven temperature, probe laser wavelength, time after ablation, and position in the laser produced plume. This data along with previously obtained data on carbon was analyzed over the academic year. Interpretations of the data were developed this summer along with discussions of future work. The temperature of the oven in which the target is ablated greatly influences the amount of material ablated and the propagation of the plume. The ablation conditions and the time scale of atomic and molecular lifetimes suggest that initial ablation of the metal doped carbon target results in atomic and small molecular species. The metal

  10. Impact of fluorescence emission from gold atoms on surrounding biological tissue—implications for nanoparticle radio-enhancement

    Science.gov (United States)

    Byrne, H. L.; Gholami, Y.; Kuncic, Z.

    2017-04-01

    The addition of gold nanoparticles within target tissue (i.e. a tumour) to enhance the delivered radiation dose is a well studied radiotherapy treatment strategy, despite not yet having been translated into standard clinical practice. While several studies have used Monte Carlo simulations to investigate radiation dose enhancement by Auger electrons emitted from irradiated gold nanoparticles, none have yet considered the effects due to escaping fluorescence photons. Geant4 was used to simulate a water phantom containing 10 mg ml‑1 uniformly dispersed gold (1% by mass) at 5 cm depth. Incident monoenergetic photons with energies either side of the gold K-edge at 73 keV and 139.5 keV were chosen to give the same attenuation contrast against water, where water is used as a surrogate for biological tissue. For 73 keV incident photons, adding 1% gold into the water phantom enhances the energy deposited in the phantom by a factor of  ≈1.9 while 139.5 keV incident photons give a lower enhancement ratio of  ≈1.5. This difference in enhancement ratio, despite the equivalent attenuation ratios, can be attributed to energy carried from the target into the surrounding volume by fluorescence photons for the higher incident photon energy. The energy de-localisation is maximal just above the K-edge with 36% of the initial energy deposit in the phantom lost to escaping fluorescence photons. Conversely we find that the absorption of more photons by gold in the phantom reduces the number of scattered photons and hence energy deposited in the surrounding volume by up to 6% for incident photons below the K-edge. For incident photons above the K-edge this is somewhat offset by fluorescence. Our results give new insight into the previously unstudied centimetre scale energy deposition outside a target, which will be valuable for the future development of treatment plans using gold nanoparticles. From these results, we can conclude that gold nanoparticles

  11. 检定原子荧光光度计常见问题分析%Atomic Fluorescence Spectrophotometer Calibration Common Problems

    Institute of Scientific and Technical Information of China (English)

    童诚; 吴银银; 马文

    2015-01-01

    This paper presents the common problems of possible atomic fluorescence spectrophotometer verification process .According to the working principle of the instrument and the experience , causes of the problems were analyzed , and specific solutions were proposed for different problems.It can guarantee accurate and reliable verification results .%提出了原子荧光光度计检定过程中可能出现的常见问题。根据经验和仪器的工作原理对问题产生的原因进行了分析,并针对不同问题给出了具体的解决措施。对实现检定结果的准确可靠具有较好的保证作用。

  12. [Butanol extraction combined with dilute hydrochloric acid dissolution-atomic fluorescence spectrometric method for indirect determination of molybdenum in Chinese herbal medicine].

    Science.gov (United States)

    Lu, Jian-Ping; Geng, Guo-Xing; Tang, Yan-Kui; Lu, Zhi-Yong

    2012-12-01

    A method for indirectly determining the molybdenum in Chinese herbal medicine by butanol extraction and dilute hydrochloric acid dissolution was established for atomic fluorescence spectrometry. The molybdoarsenate heteropoly acid, formed in the presence of As(V) and ammonium molybdate in 0.3 mol x L(-1) sulphuric acid medium, was separated and enriched in the organic solvent, then the evaporation of organic reagent was implemented and the left residue was dissolved in dilute hydrochloric acid in which the arsenic content was determined on behalf of molybdenum. In the optimum experimental conditions, molybdenum content in 0-15 microg x L(-1) range depicts a good linear relationship, the detection limit and relative standard deviation of 0.44 microg x L(-1) and 1.1% were obtained, respectively. Spiked Chinese herbal medicine samples were determined with the proposed method, and recoveries of 95.6%-101.3% were achieved.

  13. Intracellular concentration map of magnesium in whole cells by combined use of X-ray fluorescence microscopy and atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lagomarsino, Stefano, E-mail: stefano.lagomarsino@cnr.it [IPCF-CNR -UOS Roma c/o Dip Fisica Universita' ' Sapienza' , P.le A. Moro, 2 Rome (Italy); Physics Department, Universita' Sapienza, P.le A. Moro, 2 Rome (Italy); Iotti, Stefano [Dipartimento di Medicina Interna, dell' Invecchiamento e Malattie Nefrologiche Universita di Bologna, Via Massarenti, 9 40138 Bologna (Italy); Istituto Nazionale Biostrutture e Biosistemi - Rome (Italy); Farruggia, Giovanna [Dipartimento di Biochimica ' G. Moruzzi' Universita di Bologna, Via Irnerio, 48 40126 Bologna (Italy); Cedola, Alessia [IFN-CNR - V. Cineto Romano, 42 00156 Rome (Italy); Trapani, Valentina [Istituto di Patologia Generale - Universita Cattolica del Sacro Cuore - Facolta di Medicina ' A. Gemelli' L.go F. Vito, 1 00168 Rome (Italy); Fratini, Michela [IFN-CNR - V. Cineto Romano, 42 00156 Rome (Italy); Bukreeva, Inna [IFN-CNR - V. Cineto Romano, 42 00156 Rome (Italy); Shubnikov Institute of Crystallography, Leninskii prospekt 59, Moscow, 119333 (Russian Federation); Notargiacomo, Andrea [IFN-CNR - V. Cineto Romano, 42 00156 Rome (Italy); Mastrototaro, Lucia [Istituto di Patologia Generale - Universita Cattolica del Sacro Cuore - Facolta di Medicina ' A. Gemelli' L.go F. Vito, 1 00168 Rome (Italy); Marraccini, Chiara [Dipartimento di Medicina Interna, dell' Invecchiamento e Malattie Nefrologiche Universita di Bologna, Via Massarenti, 9 40138 Bologna (Italy); and others

    2011-11-15

    We report a novel experimental approach to derive quantitative concentration map of light elements in whole cells by combining two complementary nano-probe methods: X-ray fluorescence microscopy (XRFM) and atomic force microscopy (AFM). The concentration is derived by normalizing point-by-point the elemental (here Mg) spatial distribution obtained by XRFM, by the thickness measured using AFM. The considerable difference between the elemental distribution and the concentration maps indicates that this procedure is essential to obtain reliable information on the role and function of elements in whole cells. - Highlights: Black-Right-Pointing-Pointer X-ray fluorescence and AFM have been measured on the same de-hydrated whole cells. Black-Right-Pointing-Pointer The element distribution has been normalized point-by-point by the cell thickness. Black-Right-Pointing-Pointer The element (Mg) concentration map has been obtained on a whole cell. Black-Right-Pointing-Pointer The element concentration map is quite different from the distribution map. Black-Right-Pointing-Pointer Higher Mg concentration is found in the cell periphery.

  14. Detecting Neutral Atoms on an Atom Chip

    OpenAIRE

    Wilzbach, M.; Haase, A.; Schwarz, M; Heine, D.; Wicker, K.; Liu, X; Brenner, K. -H.; Groth, S.; Fernholz, Th.; Hessmo, B.; Schmiedmayer, J.

    2006-01-01

    Detecting single atoms (qubits) is a key requirement for implementing quantum information processing on an atom chip. The detector should ideally be integrated on the chip. Here we present and compare different methods capable of detecting neutral atoms on an atom chip. After a short introduction to fluorescence and absorption detection we discuss cavity enhanced detection of single atoms. In particular we concentrate on optical fiber based detectors such as fiber cavities and tapered fiber d...

  15. Determination of monomethylmercury in low- and high-polluted sediments by microwave extraction and gas chromatography with atomic fluorescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Berzas Nevado, J.J. [Regional Institute for Applied Scientific Research, University of Castilla-La Mancha, E-13071 Ciudad Real (Spain); Rodriguez Martin-Doimeadios, R.C. [Department of Analytical Chemistry and Food Technology, Faculty of Environmental Sciences, University of Castilla-La Mancha, Avda. Carlos III s/n, E-45071 Toledo (Spain)], E-mail: RosaCarmen.Rodriguez@uclm.es; Guzman Bernardo, F.J.; Jimenez Moreno, M. [Department of Analytical Chemistry and Food Technology, Faculty of Environmental Sciences, University of Castilla-La Mancha, Avda. Carlos III s/n, E-45071 Toledo (Spain)

    2008-02-04

    The analysis of monomethylmercury (MMHg) in sediments is a difficult task because both very low concentrations and interconversion between species especially in highly polluted samples are frequent. This work features a general strategy for real sediment analysis with preconcentration and/or clean-up steps for both low- and high-polluted sediments to control these specific problems. The extraction conditions have been optimized using closed-vessel microwave-assisted heating with acidic extractants. The analysis has been carried out by the injection of ethylated derivatives of the analytes into a capillary gas chromatographic system coupled to fluorescence spectrometry. When using 6 M HNO{sub 3}, the most labile inorganic mercury fraction as well as MMHg were extracted from the sediment but there was still some inorganic mercury that remained un-extracted. MMHg was stable and quantitatively recovered by applying this procedure. The role of the labile inorganic fraction on artifact MMHg generation has been evaluated and it has been found to be highly variable depending on the sediments' geochemical characteristics. Therefore, for high-polluted sediments (inorganic mercury concentration above 500 ng g{sup -1}) a clean-up step with dichloromethane has been used before ethylation, whereas for low content samples, preconcentration under nitrogen stream at room temperature has been optimized. Both steps can be combined if necessary. MMHg content has been found in good agreement with the certified value for the reference materials (IAEA-405 and ERM-CC580)

  16. Spatial dynamics of laser-induced fluorescence in an intense laser beam: experiment and theory in alkali metal atoms

    CERN Document Server

    Auzinsh, Marcis; Ferber, Ruvin; Gahbauer, Florian; Kalnins, Uldis

    2015-01-01

    We have shown that it is possible to model accurately optical phenomena in intense laser fields by taking into account the intensity distribution over the laser beam. We developed a theoretical model that divided an intense laser beam into concentric regions, each with a Rabi frequency that corresponds to the intensity in that region, and solved a set of coupled optical Bloch equations for the density matrix in each region. Experimentally obtained magneto-optical resonance curves for the $F_g=2\\longrightarrow F_e=1$ transition of the $D_1$ line of $^{87}$Rb agreed very well with the theoretical model up to a laser intensity of around 200 mW/cm$^2$ for a transition whose saturation intensity is around 4.5 mW/cm$^2$. We have studied the spatial dependence of the fluorescence intensity in an intense laser beam experimentally and theoretically. An experiment was conducted whereby a broad, intense pump laser excited the $F_g=4\\longrightarrow F_e=3$ transition of the $D_2$ line of cesium while a weak, narrow probe ...

  17. Secretion induces cell pH dynamics impacting assembly-disassembly of the fusion protein complex: A combined fluorescence and atomic force microscopy study.

    Science.gov (United States)

    Lewis, Kenneth T; Naik, Akshata R; Laha, Suvra S; Wang, Sunxi; Mao, Guangzhao; Kuhn, Eric; Jena, Bhanu P

    2017-08-03

    A wide range of cellular activities including protein folding and cell secretion, such as neurotransmission or insulin release, are all governed by intracellular pH homeostasis, underscoring the importance of pH on critical life processes. Nano- scale pH measurements of cells and biomolecules therefore hold great promise in understanding a plethora of cellular functions, in addition to disease detection and therapy. In the current study, a novel approach using cadmium telluride quantum dots (CdTeQDs) as pH sensors, combined with fluorescent imaging, spectrofluorimetry, atomic force microscopy (AFM), and Western blot analysis, enabled the study of intracellular pH dynamics at 1 milli-pH sensitivity and 80nm pixel resolution, during insulin secretion. Additionally, the pH-dependent interaction between membrane fusion proteins, also called the soluble N-ethylmaleimide-sensitive factor activating protein receptor (SNARE), was determined. Glucose stimulation of CdTeQD-loaded insulin secreting Min-6 mouse insulinoma cell line demonstrated the initial (5-6min) intracellular acidification reflected as a loss in QD fluorescence, followed by alkalization and a return to resting pH in 10min. Analysis of the SNARE complex in insulin secreting Min-6 cells demonstrated an initial gain followed by loss of complexed SNAREs in 10min. Stabilization of the SNARE complex at low intracellular pH is further supported by results from studies utilizing both native and AFM measurements of liposome-reconstituted recombinant neuronal SNAREs, providing a molecular understanding of the role of pH during cell secretion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Arsenic speciation in edible alga samples by microwave-assisted extraction and high performance liquid chromatography coupled to atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Salgado, S. [Departamento de Ingenieria Civil: Tecnologia Hidraulica y Energetica, Escuela Universitaria de Ingenieria Tecnica de Obras Publicas, Universidad Politecnica de Madrid, Alfonso XII 3 y 5, 28014 Madrid (Spain); Quijano, M.A., E-mail: marian.quijano@upm.es [Departamento de Ingenieria Civil: Tecnologia Hidraulica y Energetica, Escuela Universitaria de Ingenieria Tecnica de Obras Publicas, Universidad Politecnica de Madrid, Alfonso XII 3 y 5, 28014 Madrid (Spain); Bonilla, M.M. [Departamento de Ingenieria Civil: Tecnologia Hidraulica y Energetica, Escuela Universitaria de Ingenieria Tecnica de Obras Publicas, Universidad Politecnica de Madrid, Alfonso XII 3 y 5, 28014 Madrid (Spain)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer Total As and As species were analyzed in edible marine algae. Black-Right-Pointing-Pointer A microwave-assisted extraction method with deionized water was applied. Black-Right-Pointing-Pointer As compounds identified comprised DMA, As(V) and four arsenosugars Black-Right-Pointing-Pointer Considerably high As(V) concentrations were found in the most of the algae studied. - Abstract: Twelve commercially available edible marine algae from France, Japan and Spain and the certified reference material (CRM) NIES No. 9 Sargassum fulvellum were analyzed for total arsenic and arsenic species. Total arsenic concentrations were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) after microwave digestion and ranged from 23 to 126 {mu}g g{sup -1}. Arsenic species in alga samples were extracted with deionized water by microwave-assisted extraction and showed extraction efficiencies from 49 to 98%, in terms of total arsenic. The presence of eleven arsenic species was studied by high performance liquid chromatography-ultraviolet photo-oxidation-hydride generation atomic-fluorescence spectrometry (HPLC-(UV)-HG-AFS) developed methods, using both anion and cation exchange chromatography. Glycerol and phosphate sugars were found in all alga samples analyzed, at concentrations between 0.11 and 22 {mu}g g{sup -1}, whereas sulfonate and sulfate sugars were only detected in three of them (0.6-7.2 {mu}g g{sup -1}). Regarding arsenic toxic species, low concentration levels of dimethylarsinic acid (DMA) (<0.9 {mu}g g{sup -1}) and generally high arsenate (As(V)) concentrations (up to 77 {mu}g g{sup -1}) were found in most of the algae studied. The results obtained are of interest to highlight the need to perform speciation analysis and to introduce appropriate legislation to limit toxic arsenic species content in these food products.

  19. Femtosecond, two-photon-absorption, laser-induced-fluorescence (fs-TALIF) imaging of atomic hydrogen and oxygen in non-equilibrium plasmas

    Science.gov (United States)

    Schmidt, Jacob B.; Roy, Sukesh; Kulatilaka, Waruna D.; Shkurenkov, Ivan; Adamovich, Igor V.; Lempert, Walter R.; Gord, James R.

    2017-01-01

    Femtosecond, two-photon-absorption laser-induced fluorescence (fs-TALIF) is employed to measure space- and time-resolved distributions of atomic hydrogen and oxygen in moderate-pressure, non-equilibrium, nanosecond-duration pulsed-discharge plasmas. Temporally and spatially resolved hydrogen and oxygen TALIF images are obtained over a range of low-temperature plasmas in mixtures of helium and argon at 100 Torr total pressure. The high-peak-intensity, low-average-energy fs pulses combined with the increased spectral bandwidth compared to traditional ns-duration laser pulses provide a large number of photon pairs that are responsible for the two-photon excitation, which results in an enhanced TALIF signal. Krypton and xenon TALIF are used for quantitative calibration of the hydrogen and oxygen concentrations, respectively, with similar excitation schemes being employed. This enables 2D collection of atomic-hydrogen and -oxygen TALIF signals with absolute number densities ranging from 2  ×  1012 cm-3 to 6  ×  1015 cm-3 and 1  ×  1013 cm-3 to 3  ×  1016 cm-3, respectively. These 2D images are the first application of TALIF imaging in moderate-pressure plasma discharges. 1D self-consistent modeling predictions show agreement with experimental results within the estimated experimental error of 25%. The present results can be used to further the development of higher fidelity kinetic models while quantifying plasma-source characteristics.

  20. [Cloud Point extraction for determination of mercury in Chinese herbal medicine by hydride generation atomic fluorescence spectrometry with optimization using Box-Behnken design].

    Science.gov (United States)

    Wang, Mei; Li, Shan; Zhou, Jian-dong; Xu, Ying; Long, Jun-biao; Yang, Bing-yi

    2014-08-01

    Cloud point extraction (CPE) is proposed as a pre-concentration procedure for the determination of Hg in Chinese herbal medicine samples by hydride generation-atomic fluorescence spectrometry (HG-AFS). Hg2+ was reacted with dithizone to form hydrophobic chelate under the condition of pH. Using Triton X-114, as surfactant, chelate was quantitatively extracted into small volume of the surfactant-rich phase by heating the solution in a water bath for 15 min and centrifuging. Four variables including pH, dithizone concentration, Triton X-114 concentration and equilibrium temperature (T) showed the significant effect on extraction efficiency of total Hg evaluated by single-factor experiment, and Box-Behnken design and response surface method- ology were adopted to further investigate the mutual interactions between these variables and to identify their optimal values that would generate maximum extraction efficiency. The results showed that the binomial was used to fit the response to experimental levels of each variable. ALL linear, quadratic terms of four variables, and interactions between pH and Trion X-114, pH and di- thizone affected the response value(extraction efficiency) significantly at 5% level. The optimum extraction conditions were as follows: pH 5.1, Triton X-114 concentration of 1.16 g x L(-1), dithizone concentration of 4.87 mol x L(-1), and T 58.2 degrees C, the predicted value of fluorescence was 4528.74 under the optimum conditions, and the experimental value had only 2.1% difference with it. Under the conditions, fluorescence was linear to mercury concentration in the range of 1-5 microg x L(-1). The limit of detection obtained was 0.01247 microg x L(-1) with the relative standard deviations (R.S.D.) for six replicate determinations of 1.30%. The proposed method was successfully applied to determination of Hg in morindae Radix, Andrographitis and dried tangerine samples with the recoveries of 95.0%-100.0%. Apparently Box-Behnken design combined with

  1. A Geant4-based Simulation to Evaluate the Feasibility of Using Nuclear Resonance Fluorescence (NRF) in Determining Atomic Compositions of Body Tissue in Cancer Diagnostics and Irradiation

    Science.gov (United States)

    Gilbo, Yekaterina; Wijesooriya, Krishni; Liyanage, Nilanga

    2017-01-01

    Customarily applied in homeland security for identifying concealed explosives and chemical weapons, NRF (Nuclear Resonance Fluorescence) may have high potential in determining atomic compositions of body tissue. High energy photons incident on a target excite the target nuclei causing characteristic re-emission of resonance photons. As the nuclei of each isotope have well-defined excitation energies, NRF uniquely indicates the isotopic content of the target. NRF radiation corresponding to nuclear isotopes present in the human body is emitted during radiotherapy based on Bremsstrahlung photons generated in a linear electron accelerator. We have developed a Geant4 simulation in order to help assess NRF capabilities in detecting, mapping, and characterizing tumors. We have imported a digital phantom into the simulation using anatomical data linked to known chemical compositions of various tissues. Work is ongoing to implement the University of Virginia's cancer center treatment setup and patient geometry, and to collect and analyze the simulation's physics quantities to evaluate the potential of NRF for medical imaging applications. Preliminary results will be presented.

  2. A comparative evaluation of different ionic liquids for arsenic species separation and determination in wine varietals by liquid chromatography - hydride generation atomic fluorescence spectrometry.

    Science.gov (United States)

    Castro Grijalba, Alexander; Fiorentini, Emiliano F; Martinez, Luis D; Wuilloud, Rodolfo G

    2016-09-02

    The application of different ionic liquids (ILs) as modifiers for chromatographic separation and determination of arsenite [As(III)], arsenate [As(V)], dimethylarsonic acid (DMA) and monomethylarsonic acid (MMA) species in wine samples, by reversed-phase high performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry detection (RP-HPLC-HG-AFS) was studied in this work. Several factors influencing the chromatographic separation of the As species, such as pH of the mobile phase, buffer solution concentration, buffer type, IL concentration and length of alkyl groups in ILs were evaluated. The complete separation of As species was achieved using a C18 column in isocratic mode with a mobile phase composed of 0.5% (v/v) 1-octyl-3-methylimidazolium chloride ([C8mim]Cl) and 5% (v/v) methanol at pH 8.5. A multivariate methodology was used to optimize the variables involved in AFS detection of As species after they were separated by HPLC. The ILs showed remarkable performance for the separation of As species, which was obtained within 18min with a resolution higher than 0.83. The limits of detection for As(III), As(V), MMA and DMA were 0.81, 0.89, 0.62 and 1.00μg As L(-1). The proposed method was applied for As speciation analysis in white and red wine samples originated from different grape varieties.

  3. Automated dispersive liquid-liquid microextraction coupled to high performance liquid chromatography - cold vapour atomic fluorescence spectroscopy for the determination of mercury species in natural water samples.

    Science.gov (United States)

    Liu, Yao-Min; Zhang, Feng-Ping; Jiao, Bao-Yu; Rao, Jin-Yu; Leng, Geng

    2017-04-14

    An automated, home-constructed, and low cost dispersive liquid-liquid microextraction (DLLME) device that directly coupled to a high performance liquid chromatography (HPLC) - cold vapour atomic fluorescence spectroscopy (CVAFS) system was designed and developed for the determination of trace concentrations of methylmercury (MeHg(+)), ethylmercury (EtHg(+)) and inorganic mercury (Hg(2+)) in natural waters. With a simple, miniaturized and efficient automated DLLME system, nanogram amounts of these mercury species were extracted from natural water samples and injected into a hyphenated HPLC-CVAFS for quantification. The complete analytical procedure, including chelation, extraction, phase separation, collection and injection of the extracts, as well as HPLC-CVAFS quantification, was automated. Key parameters, such as the type and volume of the chelation, extraction and dispersive solvent, aspiration speed, sample pH, salt effect and matrix effect, were thoroughly investigated. Under the optimum conditions, linear range was 10-1200ngL(-1) for EtHg(+) and 5-450ngL(-1) for MeHg(+) and Hg(2+). Limits of detection were 3.0ngL(-1) for EtHg(+) and 1.5ngL(-1) for MeHg(+) and Hg(2+). Reproducibility and recoveries were assessed by spiking three natural water samples with different Hg concentrations, giving recoveries from 88.4-96.1%, and relative standard deviations <5.1%.

  4. Ultraviolet vapor generation atomic fluorescence spectrometric determination of mercury in natural water with enrichment by on-line solid phase extraction

    Science.gov (United States)

    Qin, Deyuan; Gao, Feng; Zhang, Zhaohui; Zhao, Liqian; Liu, Jixin; Ye, Jianping; Li, Junwei; Zheng, Fengxi

    2013-10-01

    A novel method, which coupled an on-line solid phase extraction (SPE) enrichment with ultraviolet vapor generation (UVG) atomic fluorescence spectrometry (AFS), was developed to improve the sensitivity of mercury determination and to remove the interference of some anion and organics to UVG of mercury. A high mercury retention efficiency and maximum exclusion of inorganic and organic matrix in water samples were achieved by using C18 SPE mini cartridge modified with sodium diethyldithiocarbamate (DDTC). Fast and efficient elution from the cartridge was found by using L-cysteine mixing solution. Furthermore, through the investigation of different UV reactor designs, the most important factor was the structure of the reactor (which corresponded roughly to the photon flux) wherein the tubing was sintered into the UV lamp to give the highest UV generation efficiency. The second factor was the materials of the tubing (which roughly corresponded to the working wavelength). Synthetic quartz, characterized by the highest transparency at 185 nm, attained the highest UVG efficiency, suggesting that the most favorable wavelength for UVG was 185 nm. Under optimum conditions, the achievable detection limit (3σ) with sample loadings of 10.0 mL was 0.03 ng L- 1 and 0.08 ng L- 1 with different manifolds, respectively. The method was successfully applied to the determination of Hg in tap water, river water and lake water samples.

  5. On-line continuous generation of zinc chelates in the vapor phase by reaction with sodium dithiocarbamates and determination by atomic fluorescence spectrometry

    Science.gov (United States)

    Duan, Xuchuan; Sun, Rui; Fang, Jinliang

    2017-02-01

    The present study shows for the first time that a volatile zinc chelate species can be generated by the on-line continuous merging of an acidified sample solution with an aqueous sodium diethyldithiocarbamate solution followed by rapid separation using a frit-based bubble gas-liquid separator at room temperature. The operating conditions for the generation of the vaporous zinc chelate were preliminarily investigated by non-dispersive atomic fluorescence spectrometry. The possible mechanism of zinc vapor generation is discussed. The study shows that the volatile species is an intermediate species with very similar properties to diethyldithiocarbamic acid and a very short half-life in the acidic solution. Moreover, this species can only be generated by on-line mixing and rapid separation. The efficiency of generation was 33-85% depending on acidity. Under optimal conditions, the flow rates of the sample and Na-DDTC solution were 1.3 ml min- 1, the carrier argon flow rate was 225 ml min- 1, the acid concentration of the sample solution and the concentration of Na-DDTC were 0.05 M and 0.4% (m/v), respectively, the detection limit of zinc was 0.33 (3σ) ng ml- 1, and the relative standard deviation (RSD) was 1.3%. The accuracy of the method was verified by the determination of zinc in the plant reference materials GBW10015 (spinach) and GBW10045 (rice). The results were in good agreement with the certified reference values.

  6. 原子荧光光谱法测定环境空气中锑%Antimony Determination by Atomic Fluorescence Spectrometry

    Institute of Scientific and Technical Information of China (English)

    顾志勇

    2014-01-01

    采用过氯乙烯滤膜采集环境空气中锑,盐酸-氢氟酸混酸体系微波消解滤膜,原子荧光光谱法测定锑。方法前处理操作过程简单、省时、酸用量少、环境污染小,方法的灵敏度和准确度都有很大的提高。采样体积为300L时,空气中锑的最低检出质量浓度为0.002mg/m3。%Antimony in air was sampled using perchloroethylene filter.The filter was dipped into hydrochloric acid and hydrofluoric acid system and digested by microwave.Atomic fluorescence spectrometry was used to detect anti-mony after.This process is simple and time-saving with easy pretreatment,less amount of acid,and less negative impacts on environment.In addition,the accuracy and precision of the process is better than previous methods. The detection limit of antimony in air is 0.002mg/m3 when the volume of air sample is 300 liters when this process was applied.

  7. Solid Phase Extraction of Inorganic Mercury Using 5-Phenylazo-8-hydroxyquinoline and Determination by Cold Vapor Atomic Fluorescence Spectroscopy in Natural Water Samples

    Science.gov (United States)

    Daye, Mirna; Halwani, Jalal; Hamzeh, Mariam

    2013-01-01

    8-Hydroxyquinoline (8-HQ) was chosen as a powerful ligand for Hg solid phase extraction. Among several chelating resins based on 8-HQ, 5-phenylazo-8-hydroxyquinoline (5Ph8HQ) is used for mercury extraction in which the adsorption dynamics were fully studied. It has been shown that Hg(II) is totally absorbed by 5Ph8HQ within the first 30 minutes of contact time with t1/2 5 minutes, following Langmuir adsorption model. At pH 4, the affinity of mercury is unchallenged by other metals except, for Cu(II), which have shown higher Kd value. With these latter characteristics, 5Ph8HQ was examined for the preconcentration of trace levels of Hg(II). The developed method showed quantitative recoveries of Hg(II) with LOD = 0.21 pg mL−1 and RSD = 3–6% using cold vapor atomic fluorescence spectroscopy (CV-AFS) with a preconcentration factor greater than 250. PMID:24459417

  8. Solid Phase Extraction of Inorganic Mercury Using 5-Phenylazo-8-hydroxyquinoline and Determination by Cold Vapor Atomic Fluorescence Spectroscopy in Natural Water Samples

    Directory of Open Access Journals (Sweden)

    Mirna Daye

    2013-01-01

    Full Text Available 8-Hydroxyquinoline (8-HQ was chosen as a powerful ligand for Hg solid phase extraction. Among several chelating resins based on 8-HQ, 5-phenylazo-8-hydroxyquinoline (5Ph8HQ is used for mercury extraction in which the adsorption dynamics were fully studied. It has been shown that Hg(II is totally absorbed by 5Ph8HQ within the first 30 minutes of contact time with t1/2 5 minutes, following Langmuir adsorption model. At pH 4, the affinity of mercury is unchallenged by other metals except, for Cu(II, which have shown higher Kd value. With these latter characteristics, 5Ph8HQ was examined for the preconcentration of trace levels of Hg(II. The developed method showed quantitative recoveries of Hg(II with LOD = 0.21 pg mL−1 and RSD = 3–6% using cold vapor atomic fluorescence spectroscopy (CV-AFS with a preconcentration factor greater than 250.

  9. Absolute atomic oxygen density measurements for nanosecond-pulsed atmospheric-pressure plasma jets using two-photon absorption laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Jiang, C.; Carter, C.

    2014-12-01

    Nanosecond-pulsed plasma jets that are generated under ambient air conditions and free from confinement of electrodes have become of great interest in recent years due to their promising applications in medicine and dentistry. Reactive oxygen species that are generated by nanosecond-pulsed, room-temperature non-equilibrium He-O2 plasma jets among others are believed to play an important role during the bactericidal or sterilization processes. We report here absolute measurements of atomic oxygen density in a 1 mm-diameter He/(1%)O2 plasma jet at atmospheric pressure using two-photon absorption laser-induced fluorescence spectroscopy. Oxygen number density on the order of 1013 cm-3 was obtained in a 150 ns, 6 kV single-pulsed plasma jet for an axial distance up to 5 mm above the device nozzle. Temporally resolved O density measurements showed that there are two maxima, separated in time by 60-70 µs, and a total pulse duration of 260-300 µs. Electrostatic modeling indicated that there are high-electric-field regions near the nozzle exit that may be responsible for the observed temporal behavior of the O production. Both the field-distribution-based estimation of the time interval for the O number density profile and a pulse-energy-dependence study confirmed that electric-field-dependent, direct and indirect electron-induced processes play important roles for O production.

  10. Measurement of magic-wavelength optical dipole trap by using the laser-induced fluorescence spectra of trapped single cesium atoms

    Science.gov (United States)

    Liu, Bei; Jin, Gang; Sun, Rui; He, Jun; Wang, Junmin

    2017-07-01

    Based on the multi-level model, we have calculated light shifts for Zeeman states of hyperfine levels of cesium (Cs) 6S1/2 ground state and 6P3/2 excited state.The magic-wavelength linearly-polarized optical dipole trap (ODT) for Cs 6S1/2 F=4, mF=+4 - 6P3/2 F'=5, mF=+5 transition is experimentally constructed and characterized by using the laser-induced fluorescence spectra of trapped single Cs atoms. The magic wavelength is 937.7 nm which produces almost the same light shift for 6S1/2 F=4, mF=+4 ground state and 6P3/2 F'=5, mF=+5 excited state with linearly-polarized ODT laser beam. Compared to undisturbed Cs 6S1/2 F=4, mF=+4 - 6P3/2 F'=5, mF=+5 transition frequency in free space, the differential light shift is less than 0.7 MHz in a linearly-polarized 937.7 nm ODT, which is less than 1.2% of the trap depth. We also discussed influence of the trap depth and the bias magnetic field on the measurement results.

  11. [Determination of arsenic, mercury and selenium in Gynostemma pentaphyllum and rhizospheric soil samples collected from different regions by hydride generation atomic fluorescence spectrometry].

    Science.gov (United States)

    Wang, Jing; Xiao, Ya-ping; Liang, Xiao-qing; Shao, Xian-hui; Zhang, Ke

    2012-03-01

    The contents of arsenic (As), mercury (Hg) and selenium (Se) in Gynostemma pentaphyllum and rhizospheric soil samples collected from seven provinces were determined, through the optimization of the hydride generation atomic fluorescence spectrometry working conditions. The results show that: the contents of As, Hg and Se in Gynostemma pentaphyllum from seven provinces revealed large differences, but compared with the limits of the two kinds of heavy metal element: As and Hg set by the Green Trade Standards of Importing & Exporting Medicinal Plants & Preparations (As Gynostemma pentaphyllum samples are both lower than them. The Se content in Gynostemma pentaphyllum samples and in rhizospheric soil samples revealed significant correlation, and as a result, the Gynostemma pentaphyllum from the Fu Xi area Enshi in Hu Bei province had obviously higher Se content than others in the 6 provinces. From this study, a preliminary conclusion can be drawn that Se in Gynostemma pentaphyllum is mainly from the soil, moreover, the As and Hg show the difference from Se, possibly they are still affected by the dry and wet deposition of atmospheric aerosols.

  12. An evaluation of the bioaccessibility of arsenic in corn and rice samples based on cloud point extraction and hydride generation coupled to atomic fluorescence spectrometry.

    Science.gov (United States)

    Castor, José Martín Rosas; Portugal, Lindomar; Ferrer, Laura; Hinojosa-Reyes, Laura; Guzmán-Mar, Jorge Luis; Hernández-Ramírez, Aracely; Cerdà, Víctor

    2016-08-01

    A simple, inexpensive and rapid method was proposed for the determination of bioaccessible arsenic in corn and rice samples using an in vitro bioaccessibility assay. The method was based on the preconcentration of arsenic by cloud point extraction (CPE) using o,o-diethyldithiophosphate (DDTP) complex, which was generated from an in vitro extract using polyethylene glycol tert-octylphenyl ether (Triton X-114) as a surfactant prior to its detection by atomic fluorescence spectrometry with a hydride generation system (HG-AFS). The CPE method was optimized by a multivariate approach (two-level full factorial and Doehlert designs). A photo-oxidation step of the organic species prior to HG-AFS detection was included for the accurate quantification of the total As. The limit of detection was 1.34μgkg(-1) and 1.90μgkg(-1) for rice and corn samples, respectively. The accuracy of the method was confirmed by analyzing certified reference material ERM BC-211 (rice powder). The corn and rice samples that were analyzed showed a high bioaccessible arsenic content (72-88% and 54-96%, respectively), indicating a potential human health risk.

  13. Speciation analysis of inorganic arsenic in coal samples by microwave-assisted extraction and high performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry.

    Science.gov (United States)

    Sun, Mei; Liu, Guijian; Wu, Qianghua; Liu, Wenqi

    2013-03-15

    A new method was developed for the speciation analysis of inorganic arsenic in coal samples by high performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry after microwave-assisted extraction. Effective extract of As(III) and As(V) in coal sample was achieved by 1.0 mol L(-1)H₃PO₄ and 0.1 mol L(-1)ascorbic acid. Under the optimized conditions, the limits of detection (LOD) were 0.01 μg L(-1) and 0.02 μg L(-1), the relative standard deviations (RSD) were 2.4% and 3.3% (c=10.0 μg L(-1), n=7), recoveries were 102.5% and 96.5% for As(III) and As(V). The proposed method was successfully applied for the determination of speciation of inorganic arsenic in coal samples and GBW11117 coal standard reference material with complex matrix. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Direct determination of arsenic in soil samples by fast pyrolysis-chemical vapor generation using sodium formate as a reductant followed by nondispersive atomic fluorescence spectrometry

    Science.gov (United States)

    Duan, Xuchuan; Zhang, Jingya; Bu, Fanlong

    2015-09-01

    This new study shows for the first time that sodium formate can react with trace arsenic to form volatile species via fast pyrolysis - chemical vapor generation. We found that the presence of thiourea greatly enhanced the generation efficiency and eliminated the interference of copper. We studied the reaction temperature, the volume of sodium formate, the reaction acidity, and the carried argon rate using nondispersive atomic fluorescence spectrometry. Under optimal conditions of T = 500 °C, the volumes of 30% sodium formate and 10% thiourea were 0.2 ml and 0.05 ml, respectively. The carrier argon rate was 300 ml min- 1 and the detection limit and precision of arsenic were 0.39 ng and 3.25%, respectively. The amount of arsenic in soil can be directly determined by adding trace amount of hydrochloric acid as a decomposition reagent without any sample pretreatment. The method was successfully applied to determine trace amount of arsenic in two soil-certified reference materials (GBW07453 and GBW07450), and the results were found to be in agreement with certified reference values.

  15. Direct determination of arsenic in soil samples by fast pyrolysis–chemical vapor generation using sodium formate as a reductant followed by nondispersive atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Xuchuan; Zhang, Jingya; Bu, Fanlong

    2015-09-01

    This new study shows for the first time that sodium formate can react with trace arsenic to form volatile species via fast pyrolysis – chemical vapor generation. We found that the presence of thiourea greatly enhanced the generation efficiency and eliminated the interference of copper. We studied the reaction temperature, the volume of sodium formate, the reaction acidity, and the carried argon rate using nondispersive atomic fluorescence spectrometry. Under optimal conditions of T = 500 °C, the volumes of 30% sodium formate and 10% thiourea were 0.2 ml and 0.05 ml, respectively. The carrier argon rate was 300 ml min{sup −1} and the detection limit and precision of arsenic were 0.39 ng and 3.25%, respectively. The amount of arsenic in soil can be directly determined by adding trace amount of hydrochloric acid as a decomposition reagent without any sample pretreatment. The method was successfully applied to determine trace amount of arsenic in two soil-certified reference materials (GBW07453 and GBW07450), and the results were found to be in agreement with certified reference values. - Highlights: • Sodium formate can react with trace arsenic to form volatile species via pyrolysis–chemical vapor generation. • Thiourea can enhance the generation efficiency and eliminate the interference of copper. • Arsenic in soil Sample can be directly determined without sample pretreatment.

  16. Methylmercury in water samples at the pg/L level by online preconcentration liquid chromatography cold vapor-atomic fluorescence spectrometry

    Science.gov (United States)

    Brombach, Christoph-Cornelius; Chen, Bin; Corns, Warren T.; Feldmann, Jörg; Krupp, Eva M.

    2015-03-01

    Ultra-traces of methylmercury at the sub-ppt level can be magnified in the foodweb and is of concern. In environmental monitoring a routine robust analytical method is needed to determine methylmercury in water. The development of an analytical method for ultra-trace speciation analysis of methylmercury (MeHg) in water samples is described. The approach is based on HPLC-CV-AFS with on-line preconcentration of water samples up to 200 mL, resulting in a detection limit of 40 pg/L (ppq) for MeHg, expressed as Hg. The unit consists of an optimized preconcentration column filled with a sulfur-based sorption material, on which mercury species are preconcentrated and subsequently eluted, separated and detected via HPLC-CV-AFS (high performance liquid chromatography-cold vapor atomic fluorescence spectrometry). During the method development a type of adsorbate material, the pH dependence, the sample load rate and the carry-over were investigated using breakthrough experiments. The method shows broad pH stability in the range of pH 0 to 7, without the need for buffer addition and shows limited matrix effects so that MeHg is quantitatively recovered from sewage, river and seawater directly in the acidified samples without sample preparation.

  17. Organic solvent-free reversed-phase ion-pairing liquid chromatography coupled to atomic fluorescence spectrometry for organoarsenic species determination in several matrices.

    Science.gov (United States)

    Monasterio, Romina P; Londonio, Juan A; Farias, Silvia S; Smichowski, Patricia; Wuilloud, Rodolfo G

    2011-04-27

    A novel method has been developed to determine As-containing animal feed additives including roxarsone (ROX), p-arsanilic acid (p-ASA) and nitarsone (NIT), as well as other organic As species (dimethylarsonic acid (DMAA) and monomethylarsonic acid (MMAA)) by ion-pairing high-performance liquid chromatography coupled to hydride generation atomic fluorescence spectrometry (IP-HPLC-HG-AFS). A simple isocratic reversed-phase (RP) HPLC method with a mobile phase containing citric acid and sodium hexanesulfonate (pH 2.0) was developed using a C(18) column. The use of an organic solvent free mobile phase turns this methodology into an environmentally friendly alternative. Several ion pair forming agents, such as sodium hexanesulfonate, tetrabutylammonium bisulfate and perfluoroheptanoic acid, were studied. The limits of detection for As species were calculated in standard solution and resulted to be 0.2, 0.5, 0.6, 1.6, and 1.6 μg As L(-1) for MMAA, DMAA, p-ASA, ROX and NIT, respectively. This method exhibited convenient operation, high sensitivity and good repeatability. It was applied to As speciation in different samples including arugula, dog food, dog urine and chicken liver.

  18. Studies in hydride generation atomic fluorescence determination of selenium and tellurium. Part 1 — self interference effect in hydrogen telluride generation and the effect of KI

    Science.gov (United States)

    D'Ulivo, A.; Marcucci, K.; Bramanti, E.; Lampugnani, L.; Zamboni, R.

    2000-08-01

    The effects of tetrahydroborate (0.02-1%) and iodide (0-3 M) were investigated in determination of tellurium and selenium by hydride generation atomic fluorescence spectrometry. The effect of tetrahydroborate and iodide concentration were tested on the shape of calibration curves in concentration range of 1-1000 ng ml -1 analyte. Reductant deficiency resulted in a moderate sensitivity depression for tellurium but dramatically reduced the useful dynamic range down to 50 ng ml -1. On the contrary, selenium calibration curves retained a linear character even under conditions generating strong sensitivity depression. Curvature and rollover of tellurium calibration curves has been addressed to a self-interference effect caused by the formation of finely dispersed elemental tellurium. Iodide ions were found to have beneficial or no negative effects in the hydrogen telluride generation. Addition of iodide on-line to the sample has been proved effective in the control of the self-interference effect and allows to work in mild reaction conditions. Moreover, it allows a good control of Cu(II) interference and eliminates Ni(II) and Co(II) interferences. The method has been successfully applied to determination of tellurium in copper and lead ores certified reference materials.

  19. Dual-mode chemical vapor generation for simultaneous determination of hydride-forming and non-hydride-forming elements by atomic fluorescence spectrometry.

    Science.gov (United States)

    Wang, Yu; Xu, Kailai; Jiang, Xiaoming; Hou, Xiandeng; Zheng, Chengbin

    2014-05-21

    A dual-mode chemical vapor generation integrating hydride generation and photochemical vapor generation was developed for simultaneous multi-element analysis of hydride-forming and non-hydride-forming elements by atomic fluorescence spectrometry. Four elements were selected as model elements of hydride-forming (As, Cd) and non-hydride-forming (Ni, Fe) elements to validate this proposed method. Standard or sample solutions were separately pumped to mix with tetrahydroborate, and concentrated formic acid and ammonia, and then directed to a hydride generator and a photochemical reactor to realize simultaneous hydride generation and photochemical vapor generation, respectively. Optimum conditions for dual-mode chemical vapor generation were carefully investigated. Under the optimized conditions, limits of detection of 0.05, 0.008, 0.8 and 0.1 μg L(-1) were obtained for As, Cd, Fe and Ni, respectively. The precisions were 5.0, 5.5, 4.3 and 4.5% (n = 6, RSDs) for 2 μg L(-1) of As, 1 μg L(-1) of Cd, 50 μg L(-1) of Fe and 10 μg L(-1) of Ni, respectively. This method was validated for accuracy with three certified reference water samples and applied to the simultaneous determination of these elements in a tap water sample with spike recoveries in the range of 95-99%.

  20. Determination of total Sb,Se Te, and Bi and evaluation of their inorganic species in garlic by hydride-generation-atomic-fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Matos Reyes, M.N.; Cervera, M.L.; Guardia, M. de la [University of Valencia, Department of Analytical Chemistry, Burjassot, Valencia (Spain)

    2009-07-15

    A sensitive and simple analytical method has been developed for determination of Sb(III), Sb(V), Se(IV), Se(VI), Te(IV), Te(VI), and Bi(III) in garlic samples by using hydride-generation-atomic-fluorescence spectrometry (HG-AFS). The method is based on a single extraction of the inorganic species by sonication at room temperature with 1 mol L{sup -1} H{sub 2}SO{sub 4} and washing of the solid phase with 0.1% (w/v) EDTA, followed by measurement of the corresponding hydrides generated under two different experimental conditions directly and after a pre-reduction step. The limit of detection of the method was 0.7 ng g{sup -1} for Sb(III), 1.0 ng g{sup -1} for Sb(V), 1.3 ng g{sup -1} for Se(IV), 1.0 ng g{sup -1} for Se(VI), 1.1 ng g{sup -1} for Te(IV), 0.5 ng g{sup -1} for Te(VI), and 0.9 ng g{sup -1} for Bi(III), in all cases expressed in terms of sample dry weight. (orig.)

  1. Masking Agents Evaluation for Lead Determination by Flow Injection-Hydride Generation-Atomic Fluorescence Spectrometry Technique: Effect of KI, L-Cysteine, and 1,10-Phenanthroline.

    Science.gov (United States)

    Beltrán, Blanca G; Leal, Luz O; Ferrer, Laura; Cerdà, Víctor

    2016-01-01

    Hydride generation (HG) of lead technique presents interferences from foreign ions of complex matrix samples. In order to minimize these interferences, the effect of masking agents such as KI, L-cysteine, and 1,10-phenanthroline was studied in the absence and in the presence of selected interfering species (As, Cr, Cu, and Fe). Different modes of addition of masking agents were accomplished, that is, to either sample or KBH4 reducing solution. The lead determinations were performed using a flow injection analysis (FIA) system coupled to HG and atomic fluorescence spectrometry (AFS). The linearity of calibration curves (1-10 μg Pb L(-1)) was not affected by the addition of the masking agents. The use of KI in the reducing solution diminished interferences from concentrations of As and Cu, while 1,10-phenanthroline showed a positive effect on the interference by As. Moreover, Cr and Cu appeared to be the most serious interfering ions for plumbane (PbH4), because they drastically reduced the analytical signal of lead. Fe did not present any interference under the employed experimental conditions, even at high levels. The accuracy was established through the analysis of certified reference material (i.e., BCR-610, groundwater) using KI as masking agent. The detection limit reached by FIA-HG-AFS proposed methodology was 0.03 μg Pb L(-1).

  2. Determination of Fe(II) and Fe(III) in small samples by microbore ion chromatography and photometric, atomic absorption spectrometry and total-reflection X-ray fluorescence detection

    Science.gov (United States)

    Sinner, T.; Hoffmann, P.; Ortner, H. M.

    1993-02-01

    Iron(II) and iron(III) are determined after separation on an ion Chromatographie column by various detection systems. "On-line" detection was achieved by the use of a photometer with a flow cell of 0.8 μl; for "off-line" detection, graphite furnace atomic absorption spectrometry or total-reflection X-ray fluorescence were used. The applicability of the methods is shown for standard solutions and atmospheric samples. As a typical result, 50 μg/l of iron can be determined in a 10 μl sample with a nucrobore ion chromatograph-photometer and atomic absorption system and 40 μg/l of iron in a microbore ion chromatograph-total-reflection X-ray fluorescence combination.

  3. Hydride Atomic Fluorescence Spectrophotometry Measurement Method of Arsenic and Mercury in Mineral Water%矿泉水中砷和汞的氢化物原子荧光测定法

    Institute of Scientific and Technical Information of China (English)

    韩雪飞

    2016-01-01

    Objective To analyze and determine the hydride atomic fluorescence spectrophotometry measurement method of arsenic and mercury in mineral water. Methods The hydride atomic fluorescence spectrophotometry measurement method was used by means of nitric acid by research staff. Results A certain research showed that the hydride atomic fluorescence spectrophotometry measurement method of arsenic and mercury was conducive to improving the test of materials in mineral water. Conclusion The hydride atomic fluorescence spectrophotometry measurement of arsenic and mercury in mineral water can rapidly conduct a test with relatively accurate results, and it is very suitable for the test work of mineral water, which should be promoted.%目的:分析确定矿泉水中砷和汞的氢化物原子荧光测定的方法。方法研究人员利用化学实验的方法,通过硝酸这个媒介,从而使用氢化物原子荧光测定的形式加以检验的方法。结果通过一定的研究表明,矿泉水中砷和汞的氢化物原子荧光测定法有利于提高对矿泉水中物质的检测。结论矿泉水中砷和汞的氢化物原子荧光测定不仅能够快速地进行检测,而且结果也相对准确,非常适合矿泉水的检验工作,是应该加以推广的方法。

  4. 原子荧光法测透析用水中砷硒锑汞%Atomic fluorescence measuring dialysis water arsenic selenium antimony and mercury

    Institute of Scientific and Technical Information of China (English)

    骆胜超; 李皓

    2011-01-01

    目的:建立透析用水中砷、硒、锑、汞四种微量元素的原子荧光分析法.方法:水中砷和锑加还原剂后同时测定;硒经硝酸高氯酸氧化后,再经盐酸还原后测定;汞直接加硝酸使酸度为5%后测定.结果:汞的检出限为0.024μg/L;硒的检出限为0.044μg/L;砷的检出限为0.011 μg/L;锑的检出限为0.015μg/L.结论:本法用来测定透析用水中极其微量的砷、硒、锑、汞简便快速,且在双道原子荧光法仪中可同时进行砷和锑的检测.%Objective: To establish a method for detection of hemodialysis water arsenic, selenium,antimony and mercury.Methods: Arsenic and antimony in water were detectioned after added reductant, Selenium was detectioned by nitric acid and high chlorine acid oxidationed, Mercury was directly detectioned by adding acidity to 5%. Results:The detect limit for Mercury was 0.024 muon g/L, the detect limit for Selenium was 0. 044 muon g/L, Arsenic detect limit for 0.011 muon g/L, Antimony detect limit to. 015 muon g/L. Conclusion: This method wad simple and rapid for using to determine dialysis water in extremely trace of arsenic and selenium, antimony, mercury, and in double ways for atomic fluorescence analyzer can simultaneously arsenic and antimony detection

  5. Methylmercury in water samples at the pg/L level by online preconcentration liquid chromatography cold vapor-atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Brombach, Christoph-Cornelius [Trace Element Speciation Laboratory, Department of Chemistry, Meston Walk, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Chen, Bin; Corns, Warren T. [PS Analytical, Arthur House, Crayfields Industrial Estate, Main Road, Orpington, Kent BR5 3HP (United Kingdom); Feldmann, Jörg [Trace Element Speciation Laboratory, Department of Chemistry, Meston Walk, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom); Krupp, Eva M., E-mail: e.krupp@abdn.ac.uk [Trace Element Speciation Laboratory, Department of Chemistry, Meston Walk, University of Aberdeen, Aberdeen AB24 3UE (United Kingdom)

    2015-03-01

    Ultra-traces of methylmercury at the sub-ppt level can be magnified in the foodweb and is of concern. In environmental monitoring a routine robust analytical method is needed to determine methylmercury in water. The development of an analytical method for ultra-trace speciation analysis of methylmercury (MeHg) in water samples is described. The approach is based on HPLC-CV-AFS with on-line preconcentration of water samples up to 200 mL, resulting in a detection limit of 40 pg/L (ppq) for MeHg, expressed as Hg. The unit consists of an optimized preconcentration column filled with a sulfur-based sorption material, on which mercury species are preconcentrated and subsequently eluted, separated and detected via HPLC-CV-AFS (high performance liquid chromatography–cold vapor atomic fluorescence spectrometry). During the method development a type of adsorbate material, the pH dependence, the sample load rate and the carry-over were investigated using breakthrough experiments. The method shows broad pH stability in the range of pH 0 to 7, without the need for buffer addition and shows limited matrix effects so that MeHg is quantitatively recovered from sewage, river and seawater directly in the acidified samples without sample preparation. - Highlights: • We demonstrate that a novel mixture of thiourea-thiolsilica shows an excellent trapping of MeHg between a broad pH range 1–6. • We develop the method so that it can potentially be automated for inorganic and methyl-mercury. • The method is matrix independent with highly accurate results for MeHg in hair CRM extracts and spiked water samples • The limit of detection is around 40 pg/L when just 200 mL sample is used, without any intensive preparation.

  6. Speciation analysis of mercury in sediments, zoobenthos and river water samples by high-performance liquid chromatography hyphenated to atomic fluorescence spectrometry following preconcentration by solid phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Margetinova, Jana; Houserova-Pelcova, Pavlina [Department of Chemistry and Biochemistry, Mendel University of Agriculture and Forestry, Zemedelska 1, Brno CZ 613 00 (Czech Republic); Kuban, Vlastimil [Department of Chemistry and Biochemistry, Mendel University of Agriculture and Forestry, Zemedelska 1, Brno CZ 613 00 (Czech Republic)], E-mail: kuban@mendelu.cz

    2008-05-19

    A high-pressure microwave digestion was applied for microwave-assisted extraction (MAE) of mercury species from sediments and zoobenthos samples. A mixture containing 3 mol L{sup -1} HCl, 50% aqueous methanol and 0.2 mol L{sup -1} citric acid (for masking co-extracted Fe{sup 3+}) was selected as the most suitable extraction agent. The efficiency of proposed extraction method was better than 95% with R.S.D. below 6%. A preconcentration method utilizing a 'homemade' C18 solid phase extraction (SPE) microcolumns was developed to enhance sensitivity of the mercury species determination using on-column complex formation of mercury-2-mercaptophenol complexes. Methanol was chosen for counter-current elution of the retained mercury complexes achieving a preconcentration factor as much as 1000. The preconcentration method was applied for the speciation analysis of mercury in river water samples. The high-performance liquid chromatography-cold vapour atomic fluorescence spectrometric (HPLC/CV-AFS) method was used for the speciation analysis of mercury. The complete separation of four mercury species was achieved by an isocratic elution of aqueous methanol (65%/35%) on a Zorbax SB-C18 column (4.6 mm x 150 mm, 5 {mu}m) using the same complexation reagent (2-mercaptophenol). The limits of detection were 4.3 {mu}g L{sup -1} for methylmercury (MeHg{sup +}), 1.4 {mu}g L{sup -1} for ethylmercury (EtHg{sup +}), 0.8 {mu}g L{sup -1} for inorganic mercury (Hg{sup 2+}), 0.8 {mu}g L{sup -1} for phenylmercury (PhHg{sup +})

  7. Gold-coated silica as a preconcentration phase for the determination of total dissolved mercury in natural waters using atomic fluorescence spectrometry.

    Science.gov (United States)

    Leopold, Kerstin; Foulkes, Michael; Worsfold, Paul J

    2009-05-01

    A novel solid-phase preconcentration method is reported, using in-house gold-coated silica adsorbent packed in a microcolumn, for the determination of dissolved mercury in natural waters by atomic fluorescence spectrometry (AFS). The adsorbent was prepared by chemical reduction of a Au(III) solution with hydroxylamine in the presence of suspended silica particles. The resulting Au nanoparticles on the silica surface were highly efficient for adsorbing different mercury species from acidified waters without additional reagents. The acidified aqueous samples were passed over the microcolumn, either incorporated in a fully automated flow injection (FI) system directly coupled to the AFS or as part of a portable FI system for in situ preconcentration. After rinsing and drying of the column, Hg(0) was released by heating and directed to the AFS cell for quantification. The method offers significant advantages because no reagents are needed for species conversion, preconcentration, sample storage, or desorption and therefore the risk of contamination is minimized and blank values are lowered. This results in a low detection limit of 180 pg L(-1) using a sample volume of only 7 mL and good reproducibility, with relative standard deviations 90% in spiked river waters (spiked [Hg] = 0, 1, 5, 10 ng L(-1)), and the experimental value for the certified reference material ORMS-4 (elevated mercury in river water) was 22.3 +/- 2.6 ng Hg L(-1) which was in good agreement with the certified value of 22.0 +/- 1.6 ng Hg L(-1) (recovery = 101%). The method was successfully applied to seven different natural waters and wastewaters ([Hg] 0.5-4.6 ng L(-1)) from south west England.

  8. Arsenic fractionation in agricultural soil using an automated three-step sequential extraction method coupled to hydride generation-atomic fluorescence spectrometry.

    Science.gov (United States)

    Rosas-Castor, J M; Portugal, L; Ferrer, L; Guzmán-Mar, J L; Hernández-Ramírez, A; Cerdà, V; Hinojosa-Reyes, L

    2015-05-18

    A fully automated modified three-step BCR flow-through sequential extraction method was developed for the fractionation of the arsenic (As) content from agricultural soil based on a multi-syringe flow injection analysis (MSFIA) system coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS). Critical parameters that affect the performance of the automated system were optimized by exploiting a multivariate approach using a Doehlert design. The validation of the flow-based modified-BCR method was carried out by comparison with the conventional BCR method. Thus, the total As content was determined in the following three fractions: fraction 1 (F1), the acid-soluble or interchangeable fraction; fraction 2 (F2), the reducible fraction; and fraction 3 (F3), the oxidizable fraction. The limits of detection (LOD) were 4.0, 3.4, and 23.6 μg L(-1) for F1, F2, and F3, respectively. A wide working concentration range was obtained for the analysis of each fraction, i.e., 0.013-0.800, 0.011-0.900 and 0.079-1.400 mg L(-1) for F1, F2, and F3, respectively. The precision of the automated MSFIA-HG-AFS system, expressed as the relative standard deviation (RSD), was evaluated for a 200 μg L(-1) As standard solution, and RSD values between 5 and 8% were achieved for the three BCR fractions. The new modified three-step BCR flow-based sequential extraction method was satisfactorily applied for arsenic fractionation in real agricultural soil samples from an arsenic-contaminated mining zone to evaluate its extractability. The frequency of analysis of the proposed method was eight times higher than that of the conventional BCR method (6 vs 48 h), and the kinetics of lixiviation were established for each fraction.

  9. Comparison of a portable micro-X-ray fluorescence spectrometry with inductively coupled plasma atomic emission spectrometry for the ancient ceramics analysis

    Energy Technology Data Exchange (ETDEWEB)

    Papadopoulou, D.N. [Laboratory of Analytical Chemistry, Faculty of Chemistry, Aristotle University, GR-54124, Thessaloniki (Greece); Zachariadis, G.A. [Laboratory of Analytical Chemistry, Faculty of Chemistry, Aristotle University, GR-54124, Thessaloniki (Greece); Anthemidis, A.N. [Laboratory of Analytical Chemistry, Faculty of Chemistry, Aristotle University, GR-54124, Thessaloniki (Greece); Tsirliganis, N.C. [Archaeometry Laboratory, Cultural and Educational Technology Institute, Tsimiski 58, GR-67100, Xanthi (Greece); Stratis, J.A. [Laboratory of Analytical Chemistry, Faculty of Chemistry, Aristotle University, GR-54124, Thessaloniki (Greece)]. E-mail: jstratis@chem.auth.gr

    2004-12-01

    Two multielement instrumental methods of analysis, micro X-ray fluorescence spectrometry (micro-XRF) and inductively coupled plasma atomic emission spectrometry (ICP-AES) were applied for the analysis of 7th and 5th century B.C. ancient ceramic sherds in order to evaluate the above two methods and to assess the potential to use the current compact and portable micro-XRF instrument for the in situ analysis of ancient ceramics. The distinguishing factor of interest is that micro-XRF spectrometry offers the possibility of a nondestructive analysis, an aspect of primary importance in the compositional analysis of cultural objects. Micro-XRF measurements were performed firstly directly on the ceramic sherds with no special pretreatment apart from surface cleaning (micro-XRF on sherds) and secondly on pressed pellet disks which were prepared for each ceramic sherd (micro-XRF on pellet). For the ICP-AES determination of elements, test solutions were prepared by the application of a microwave-assisted decomposition procedure in closed high-pressure PFA vessels. Also, the standard reference material SARM 69 was used for the efficiency calibration of the micro-XRF instrument and was analysed by both methods. In order to verify the calibration, the standard reference materials NCS DC 73332 and SRM620 as well as the reference materials AWI-1 and PRI-1 were analysed by micro-XRF. Elemental concentrations determined by the three analytical procedures (ICP-AES, micro-XRF on sherds and micro-XRF on pellets) were statistically treated by correlation analysis and Student's t-test (at the 95% confidence level)

  10. Label-Free and Separation-Free Atomic Fluorescence Spectrometry-Based Bioassay: Sensitive Determination of Single-Strand DNA, Protein, and Double-Strand DNA.

    Science.gov (United States)

    Chen, Piaopiao; Wu, Peng; Chen, Junbo; Yang, Peng; Zhang, Xinfeng; Zheng, Chengbin; Hou, Xiandeng

    2016-02-16

    Based on selective and sensitive determination of Hg(2+) released from mercury complex by cold vapor generation (CVG) atomic fluorescence spectrometry (AFS) using SnCl2 as a reductant, a novel label-free and separation-free strategy was proposed for DNA and protein bioassay. To construct the DNA bioassay platform, an Hg(2+)-mediated molecular beacon (hairpin) without labeling but possessing several thymine (T) bases at both ends was employed as the probe. It is well-known that Hg(2+) could trigger the formation of the hairpin structure through T-Hg(2+)-T connection. In the presence of a specific target, the hairpin structure could be broken and the captured Hg(2+) was released. Interestingly, it was found that SnCl2 could selectively reduce only free Hg(2+) to Hg(0) vapor in the presence of T-Hg(2+)-T complex, which could be separated from sample matrices for sensitive AFS detection. Three different types of analyte, namely, single-strand DNA (ssDNA), protein, and double-strand DNA (dsDNA), were investigated as the target analytes. Under the optimized conditions, this bioassay provided high sensitivity for ssDNA, protein, and dsDNA determination with the limits of detection as low as 0.2, 0.08, and 0.3 nM and the linear dynamic ranges of 10-150, 5-175, and 1-250 nM, respectively. The analytical performance for these analytes compares favorably with those by previously reported methods, demonstrating the potential usefulness and versatility of this new AFS-based bioassay. Moreover, the bioassay retains advantages of simplicity, cost-effectiveness, and sensitivity compared to most of the conventional methods.

  11. Determination of thiomersal by flow injection coupled with microwave-assisted photochemical online oxidative decomposition of organic mercury and cold vapor atomic fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Campanella, Beatrice; Onor, Massimo; Mascherpa, Marco Carlo; D’Ulivo, Alessandro [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici-ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Ferrari, Carlo [National Research Council of Italy, C.N.R., Istituto Nazionale di Ottica, INO–UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Bramanti, Emilia, E-mail: bramanti@pi.iccom.cnr.it [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici-ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy)

    2013-12-04

    Graphical abstract: -- Highlights: •Thiomersal was determined on line using FI-MW/UV-CVGAFS. •MW/UV allows a “green” on line oxidation of organic mercury to Hg{sup II}. •Each measure requires less than 5 min with a LOD of 3 ng mL{sup −1} (as mercury). •Hg concentration in commercial ophthalmic solutions ranges between 7.5 and 59.0 μg mL{sup −1}. -- Abstract: We developed a flow injection (FI) method for the determination of thiomersal (sodium ethylmercurithiosalicylate, C{sub 9}H{sub 9}HgNaO{sub 2}S) based on the UV/microwave (MW) photochemical, online oxidation of organic mercury, followed by cold vapor generation atomic fluorescence spectrometry (CVG-AFS) detection. Thiomersal was quantitatively converted in the MW/UV process to Hg(II), with a yield of 97 ± 3%. This reaction was followed by the reduction of Hg(II) to Hg(0) performed in a knotted reaction coil with NaBH{sub 4} solution, and AFS detection in an Ar/H{sub 2} miniaturized flame. The method was linear in the 0.01–2 μg mL{sup −1} range, with a LOD of 0.003 μg mL{sup −1}. This method has been applied to the determination of thiomersal in ophthalmic solutions, with recoveries ranging between 97% and 101%. We found a mercury concentration in commercial ophthalmic solutions ranging between 7.5 and 59.0 μg mL{sup −1}.

  12. The distribution of photosynthetic products and grain plumpness of two-line intersubspecific hybrid rice

    Institute of Scientific and Technical Information of China (English)

    ZHANGHuaiyu; WANGHuaxin; ZHANGZhongling; WUSuqiong; CHENZhiyu

    1997-01-01

    The utilization of two-line intersubspecific hybrid vigor is an important way to increase yield of rice. However, the poor plumpness of grains in many combinations is an obstacle for using the method, We analyzed the relationship between the translocation rate of photosynthetic products into grains and the grain plumpness by the aid of 14C tracer technique.

  13. Conductance measurement by two-line probe method of polypyrrole nano-films formed on mica by admicellar polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Mou, C.-Y. [Graduate Institute of Textile Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Yuan, W.-L. [Department of Chemical Engineering, Feng Chia University, Taichung 40724, Taiwan (China)], E-mail: wyuan@fcu.edu.tw; Tsai, I-S. [Graduate Institute of Textile Engineering, Feng Chia University, Taichung 40724, Taiwan (China); O' Rear, Edgar A. [School of Chemical, Biological and Material Engineering, University of Oklahoma, Norman, OK 73019 (United States); Barraza, Harry [Unilever R and D HPC, Quarry Road East, Bebington, Wirral, CH63 3JW (United Kingdom)

    2008-10-01

    Measuring the electrical conductance is of importance in fabricating electronic devices based on semiconducting thin films. In this report, electrically conducting polypyrrole (PPy) nano-films were deposited on insulating mica plates by admicellar polymerization. It becomes difficult to measure such film conductance in the lateral direction due the nanometric thickness which only allows for very low electrical current. In order to understand the effects of surfactant on the film conductivity, morphological studies using atomic force microscopy and conductance measurements with a sub-fA multimeter were performed. Higher conductances were found for PPy thin films made using surfactant templates, than that of a bare mica surface. Using the two-line probe method by drawing two lines of silver glue 8 mm apart on the sample surface, the current-voltage curves of bare mica surface yielded a lateral conductance of 6.0 x 10{sup -13} S. In comparison, PPy thin films made using sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB) as surfactant templates showed conductances of 1.2 x 10{sup -11} S and 7.7 x 10{sup -12} S, respectively. The higher conductances indicate tunneling, hopping, and percolation of charge carriers throughout the films. The lower-bound conductivities were calculated as 4.0 x 10{sup -3} S/cm and 2.6 x 10{sup -3} S/cm, measured based on the average thickness 2.3 nm for the SDS-PPy films and 2.4 nm for the CTAB-PPy films. Conductivities for both SDS and CTAB template PPy films are found to be of the same order.

  14. Mechanism of laser induced fluorescence signal generation in InCl3-ethanol mixture flames

    Science.gov (United States)

    Fang, Bolang; Hu, Zhiyun; Zhang, Zhenrong; Li, Guohua; Shao, Jun; Feng, Guobin

    2017-05-01

    Nonlinear regime Two-line Atomic Fluorescence (NTLAF) is a promising technique for two-dimensional thermometry. A key challenge is seeding of indium atoms into flame. This work aims at investigating the mechanism of Indium LIF signal generation in a fuel-rich InCl3-ethanol premixed flame. Several types of images including natural emission of the flame itself, natural emission of CH, natural emission of OH, natural emission at 410 nm/451 nm of indium atom, and laser induced fluorescence at 410 nm/451 nm were obtained. The indium atom was generated in the flame front, and could survive in the post-flame zone for a while which is benefit for making NTLAF measurements. Further detail mechanism of fluorescence signals generation in InCl3-ethanol solution burning was investigated. The conclusion which probable to be drew is that to gain high NTLAF signals, the size of liquid droplets should be well controlled, neither to be too large nor to be gasified.

  15. Ionic liquid-based zinc oxide nanofluid for vortex assisted liquid liquid microextraction of inorganic mercury in environmental waters prior to cold vapor atomic fluorescence spectroscopic detection.

    Science.gov (United States)

    Amde, Meseret; Liu, Jing-Fu; Tan, Zhi-Qiang; Bekana, Deribachew

    2016-01-01

    Zinc oxide nanofluid (ZnO-NF) based vortex assisted liquid liquid microextraction (ZnO-NF VA-LLME) was developed and employed in extraction of inorganic mercury (Hg(2+)) in environmental water samples, followed by cold vapor atomic fluorescence spectrometry (CV-AFS). Unlike other dispersive liquid liquid microextraction techniques, ZnO-NF VA-LLME is free of volatile organic solvents and dispersive solvent consumption. Analytical signals were obtained without back-extraction from the ZnO-NF phase prior to CV-AFS determination. Some essential parameters of the ZnO-NF VA-LLME and cold vapor generation such as composition and volume of the nanofluid, vortexing time, pH of the sample solution, amount of the chelating agent, ionic strength and matrix interferences have been studied. Under optimal conditions, efficient extraction of 1ng/mL of Hg(2+) in 10mL of sample solution was achieved using 50μL of ZnO-NF. The enrichment factor before dilution, detection limits and limits of quantification of the method were about 190, 0.019 and 0.064ng/mL, respectively. The intra and inter days relative standard deviations (n=8) were found to be 4.6% and 7.8%, respectively, at 1ng/mL spiking level. The accuracy of the current method was also evaluated by the analysis of certified reference materials, and the measured Hg(2+) concentration of GBW08603 (9.6ng/mL) and GBW(E)080392 (8.9ng/mL) agreed well with their certified value (10ng/mL). The method was applied to the analysis of Hg(2+) in effluent, influent, lake and river water samples, with recoveries in the range of 79.8-92.8% and 83.6-106.1% at 1ng/mL and 5ng/mL spiking levels, respectively. Overall, ZnO-NF VA-LLME is fast, simple, cost-effective and environmentally friendly and it can be employed for efficient enrichment of the analyte from various water samples.

  16. Determination of hydrogen sulfide and volatile thiols in air samples by mercury probe derivatization coupled with liquid chromatography-atomic fluorescence spectrometry.

    Science.gov (United States)

    Bramanti, Emilia; D'Ulivo, Lucia; Lomonte, Cristina; Onor, Massimo; Zamboni, Roberto; Raspi, Giorgio; D'Ulivo, Alessandro

    2006-10-02

    A new procedure is proposed for the sampling and storage of hydrogen sulphide (H2S) and volatile thiols (methanethiol or methyl mercaptan, ethanethiol and propanethiol) for their determination by liquid chromatography. The sampling procedure is based on the trapping/pre-concentration of the analytes in alkaline aqueous solution containing an organic mercurial probe p-hydroxymercurybenzoate, HO-Hg-C6H4-COO- (PHMB), where they are derivatized to stable PHMB complexes based on mercury-sulfur covalent bonds. PHMB complexes are separated on a C18 reverse phase column, allowing their determination by liquid chromatography coupled with sequential non-selective UV-vis (DAD) and mercury specific (chemical vapor generation atomic fluorescence spectrometry, CVGAFS) on-line detectors. PHMB complexes, S(PHMB)2CH3S-PHMB, C2H5S-PHMB and C3H7S-PHMB, are stable alt least for 12 h at room temperature and for 3 months if stored frozen (-20 degrees C). The best analytical figures of merits in the optimized conditions were obtained by CVGAFS detection, with detection limits (LODc) of 9.7 microg L(-1) for H2S, 13.7 microg L(-1) for CH(3)SH, 17.7 microg L(-1) for C2H5SH and 21.7 microg L(-1) for C3H7SH in the trapping solution in form of RS-PHMB complexes, the relative standard deviation (R.S.D.) ranging between 1.0 and 1.5%, and a linear dynamic range (LDR) between 10 and 9700 microg L(-1). Conventional UV absorbance detectors tuned at 254 nm can be employed as well with comparable R.S.D. and LDR, but with LODc one order of magnitude higher than AFS detector and lower specificity. The sampling procedure followed by LC-DAD-CVGAFS analysis has been validated, as example, for H2S determination by a certified gas permeation tube as a source of 3.071+/-0.154 microg min(-1) of H2S, giving a recovery of 99.8+/-7% and it has been applied to the determination of sulfur compounds in real gas samples (biogas and the air of a plant for fractional distillation of crude oil).

  17. Arsenic fractionation in agricultural soil using an automated three-step sequential extraction method coupled to hydride generation-atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Rosas-Castor, J.M. [Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León (Mexico); Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca (Spain); Portugal, L.; Ferrer, L. [Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca (Spain); Guzmán-Mar, J.L.; Hernández-Ramírez, A. [Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León (Mexico); Cerdà, V. [Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca (Spain); Hinojosa-Reyes, L., E-mail: laura.hinojosary@uanl.edu.mx [Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León (Mexico)

    2015-05-18

    Highlights: • A fully automated flow-based modified-BCR extraction method was developed to evaluate the extractable As of soil. • The MSFIA–HG-AFS system included an UV photo-oxidation step for organic species degradation. • The accuracy and precision of the proposed method were found satisfactory. • The time analysis can be reduced up to eight times by using the proposed flow-based BCR method. • The labile As (F1 + F2) was <50% of total As in soil samples from As-contaminated-mining zones. - Abstract: A fully automated modified three-step BCR flow-through sequential extraction method was developed for the fractionation of the arsenic (As) content from agricultural soil based on a multi-syringe flow injection analysis (MSFIA) system coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS). Critical parameters that affect the performance of the automated system were optimized by exploiting a multivariate approach using a Doehlert design. The validation of the flow-based modified-BCR method was carried out by comparison with the conventional BCR method. Thus, the total As content was determined in the following three fractions: fraction 1 (F1), the acid-soluble or interchangeable fraction; fraction 2 (F2), the reducible fraction; and fraction 3 (F3), the oxidizable fraction. The limits of detection (LOD) were 4.0, 3.4, and 23.6 μg L{sup −1} for F1, F2, and F3, respectively. A wide working concentration range was obtained for the analysis of each fraction, i.e., 0.013–0.800, 0.011–0.900 and 0.079–1.400 mg L{sup −1} for F1, F2, and F3, respectively. The precision of the automated MSFIA–HG-AFS system, expressed as the relative standard deviation (RSD), was evaluated for a 200 μg L{sup −1} As standard solution, and RSD values between 5 and 8% were achieved for the three BCR fractions. The new modified three-step BCR flow-based sequential extraction method was satisfactorily applied for arsenic fractionation in real agricultural

  18. Determination of mercury species by the diffusive gradient in thin film technique and liquid chromatography – atomic fluorescence spectrometry after microwave extraction

    Energy Technology Data Exchange (ETDEWEB)

    Pelcová, Pavlína, E-mail: pavlina.pelcova@mendelu.cz; Dočekalová, Hana, E-mail: hana.docekalova@mendelu.cz; Kleckerová, Andrea, E-mail: andrea.kleckerova@mendelu.cz

    2015-03-25

    Highlights: • DGT–MAE–LC–CV-AFS method was developed for determination of four mercury species. • The microwave extraction was used for isolation of mercury species from resin gels. • Optimized DGT–MAE–LC–CV-AFS method provides low detection limits (13–38 ng L{sup −1}). • The diffusion coefficients of four mercury species were simultaneously determined. - Abstract: A diffusive gradient in thin films technique (DGT) was combined with liquid chromatography (LC) and cold vapor atomic fluorescence spectrometry (CV-AFS) for the simultaneous quantification of four mercury species (Hg{sup 2+}, CH{sub 3}Hg{sup +}, C{sub 2}H{sub 5}Hg{sup +}, and C{sub 6}H{sub 5}Hg{sup +}). After diffusion through an agarose diffusive layer, the mercury species were accumulated in resin gels containing thiol-functionalized ion-exchange resins (Duolite GT73, and Ambersep GT74). A microwave-assisted extraction (MAE) in the presence of 6 M HCl and 5 M HCl (55 °C, 15 min) was used for isolation of mercury species from Ambersep and Duolite resin gels, respectively. The extraction efficiency was higher than 95.0% (RSD 3.5%). The mercury species were separated with a mobile phase containing 6.2% methanol + 0.05% 2-mercaptoethanol + 0.02 M ammonium acetate with a stepwise increase of methanol content up to 80% in the 16th min on a Zorbax C18 reverse phase column. The LODs of DGT–MAE–LC–CV-AFS method were 38 ng L{sup −1} for CH{sub 3}Hg{sup +}, 13 ng L{sup −1} for Hg{sup 2+}, 34 ng L{sup −1} for C{sub 2}H{sub 5}Hg{sup +} and 30 ng L{sup −1} for C{sub 6}H{sub 5}Hg{sup +} for 24 h DGT accumulation at 25 °C.

  19. Determination of hydrogen sulfide and volatile thiols in air samples by mercury probe derivatization coupled with liquid chromatography-atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bramanti, Emilia [Italian National Research Council, CNR-Istituto per i Processi Chimico-Fisici, Laboratory of Instrumental Analytical Chemistry, Via G. Moruzzi 1, 56124 Pisa (Italy)]. E-mail: emilia@ipcf.cnr.it; D' Ulivo, Lucia [Italian National Research Council, CNR-Istituto per i Processi Chimico-Fisici, Laboratory of Instrumental Analytical Chemistry, Via G. Moruzzi 1, 56124 Pisa (Italy); Lomonte, Cristina [Italian National Research Council, CNR-Istituto per i Processi Chimico-Fisici, Laboratory of Instrumental Analytical Chemistry, Via G. Moruzzi 1, 56124 Pisa (Italy); Ambiente s.c.r.l., Via Frassina 21, 54033, Carrrara, Massa (Italy); Onor, Massimo [Italian National Research Council, CNR-Istituto per i Processi Chimico-Fisici, Laboratory of Instrumental Analytical Chemistry, Via G. Moruzzi 1, 56124 Pisa (Italy); Zamboni, Roberto [Department of Chemistry and Industrial Chemistry, University of Pisa, Via Risorgimento 35, 56126 Pisa (Italy); Raspi, Giorgio [Italian National Research Council, CNR-Istituto per i Processi Chimico-Fisici, Laboratory of Instrumental Analytical Chemistry, Via G. Moruzzi 1, 56124 Pisa (Italy); D' Ulivo, Alessandro [Italian National Research Council, CNR-Istituto per i Processi Chimico-Fisici, Laboratory of Instrumental Analytical Chemistry, Via G. Moruzzi 1, 56124 Pisa (Italy)

    2006-10-02

    A new procedure is proposed for the sampling and storage of hydrogen sulphide (H{sub 2}S) and volatile thiols (methanethiol or methyl mercaptan, ethanethiol and propanethiol) for their determination by liquid chromatography. The sampling procedure is based on the trapping/pre-concentration of the analytes in alkaline aqueous solution containing an organic mercurial probe p-hydroxymercurybenzoate, HO-Hg-C{sub 6}H{sub 4}-COO{sup -} (PHMB), where they are derivatized to stable PHMB complexes based on mercury-sulfur covalent bonds. PHMB complexes are separated on a C{sub 18} reverse phase column, allowing their determination by liquid chromatography coupled with sequential non-selective UV-vis (DAD) and mercury specific (chemical vapor generation atomic fluorescence spectrometry, CVGAFS) on-line detectors. PHMB complexes, S(PHMB){sub 2}CH{sub 3}S-PHMB, C{sub 2}H{sub 5}S-PHMB and C{sub 3}H{sub 7}S-PHMB, are stable alt least for 12 h at room temperature and for 3 months if stored frozen (-20 deg. C). The best analytical figures of merits in the optimized conditions were obtained by CVGAFS detection, with detection limits (LODc) of 9.7 {mu}g L{sup -1} for H{sub 2}S, 13.7 {mu}g L{sup -1} for CH{sub 3}SH, 17.7 {mu}g L{sup -1} for C{sub 2}H{sub 5}SH and 21.7 {mu}g L{sup -1} for C{sub 3}H{sub 7}SH in the trapping solution in form of RS-PHMB complexes, the relative standard deviation (R.S.D.) ranging between 1.0 and 1.5%, and a linear dynamic range (LDR) between 10 and 9700 {mu}g L{sup -1}. Conventional UV absorbance detectors tuned at 254 nm can be employed as well with comparable R.S.D. and LDR, but with LODc one order of magnitude higher than AFS detector and lower specificity. The sampling procedure followed by LC-DAD-CVGAFS analysis has been validated, as example, for H{sub 2}S determination by a certified gas permeation tube as a source of 3.071 {+-} 0.154 {mu}g min{sup -1} of H{sub 2}S, giving a recovery of 99.8 {+-} 7% and it has been applied to the determination of

  20. 高压消解-原子荧光光谱法测定牛初乳中硒的研究%High Pressure Digestion - Atomic Fluorescence Spectrometric Determination of Selenium in Bovine Colostrum

    Institute of Scientific and Technical Information of China (English)

    汪波; 辛跃珍

    2012-01-01

    Established by hydride atomic fluorescence method for the determination of selenium in bovine colostrum, investigates the methods of pretreatment and atom fluorescence instrument effects on the experimental results, and finally determine the digestion reagent6: 2: : 1: nitrate hydrogen peroxide: ultrapure water, with high pressure digestion of bovine colostrum samples, digestion temperature 130-140C, time 2-3hours; atomic fluorescence reducing agent forl4g / L potassium borohydride, load flow solution for 5% hydrochloric acid. Get the selenium detection limit of0.1ng / ml, the relative standard deviation for0.!6%-1.61%, recovery rate range for 88%-102%.%建立了用氢化物原子荧光法测定牛初乳中的硒,考察了前处理方法和原子荧光仪器对实验结果的影响,最后确定了消解试剂6:2::1的硝酸:过氧化氢:超纯水,用高压消解法处理牛初乳样品,消解温度130—140℃,时间2—3小时;原子荧光的还原剂为14g/l的硼氢化钾,载流液为5%的盐酸。得到硒的检出限0.1ng/ml,相对标准偏差为0.16%-1.61%,回收率范围为88%-102%。

  1. A New High-Yielding Two-line Hybrid Rice Variety - Peiliang You 981

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ Peiliang You 981 (also called 98 Guangzhi 1 or Peiliang You Guangzhi 1) is a late-season two-line indica hybrid rice variety with high yield and late maturity. Pei'ai 64S is the female parent and R981 (Guang 1) is the male parent of Peiliang You 981. The hybrid showed its characters of high and stable yield and wide adaptability in the variety trials and demonstration production in the recent years, and it was released in March 2002 by Hunan Crop Varieties Release Committee.

  2. Methodology using a portable X-ray fluorescence device for on-site and rapid evaluation of heavy-atom contamination in wounds: a model study for application to plutonium contamination.

    Directory of Open Access Journals (Sweden)

    Hiroshi Yoshii

    Full Text Available Workers decommissioning the Fukushima-Daiichi nuclear power plant damaged from the Great East Japan Earthquake and resulting tsunami are at risk of injury with possible contamination from radioactive heavy atoms including actinides, such as plutonium. We propose a new methodology for on-site and rapid evaluation of heavy-atom contamination in wounds using a portable X-ray fluorescence (XRF device. In the present study, stable lead was used as the model contaminant substitute for radioactive heavy atoms. First, the wound model was developed by placing a liquid blood phantom on an epoxy resin wound phantom contaminated with lead. Next, the correlation between the concentration of contaminant and the XRF peak intensity was formulated considering the thickness of blood exiting the wound. Methods to determine the minimum detection limit (MDL of contaminants at any maximal equivalent dose to the wound by XRF measurement were also established. For example, in this system, at a maximal equivalent dose of 16.5 mSv to the wound and blood thickness of 0.5 mm, the MDL value for lead was 1.2 ppm (3.1 nmol. The radioactivity of 239Pu corresponding to 3.1 nmol is 1.7 kBq, which is lower than the radioactivity of 239Pu contaminating puncture wounds in previous severe accidents. In conclusion, the established methodology could be beneficial for future development of a method to evaluate plutonium contamination in wounds. Highlights: Methodology for evaluation of heavy-atom contamination in a wound was established. A portable X-ray fluorescence device enables on-site, rapid and direct evaluation. This method is expected to be used for evaluation of plutonium contamination in wounds.

  3. Methodology using a portable X-ray fluorescence device for on-site and rapid evaluation of heavy-atom contamination in wounds: a model study for application to plutonium contamination.

    Science.gov (United States)

    Yoshii, Hiroshi; Yanagihara, Kouta; Imaseki, Hitoshi; Hamano, Tsuyoshi; Yamanishi, Hirokuni; Inagaki, Masayo; Sakai, Yasuhiro; Sugiura, Nobuyuki; Kurihara, Osamu; Sakai, Kazuo

    2014-01-01

    Workers decommissioning the Fukushima-Daiichi nuclear power plant damaged from the Great East Japan Earthquake and resulting tsunami are at risk of injury with possible contamination from radioactive heavy atoms including actinides, such as plutonium. We propose a new methodology for on-site and rapid evaluation of heavy-atom contamination in wounds using a portable X-ray fluorescence (XRF) device. In the present study, stable lead was used as the model contaminant substitute for radioactive heavy atoms. First, the wound model was developed by placing a liquid blood phantom on an epoxy resin wound phantom contaminated with lead. Next, the correlation between the concentration of contaminant and the XRF peak intensity was formulated considering the thickness of blood exiting the wound. Methods to determine the minimum detection limit (MDL) of contaminants at any maximal equivalent dose to the wound by XRF measurement were also established. For example, in this system, at a maximal equivalent dose of 16.5 mSv to the wound and blood thickness of 0.5 mm, the MDL value for lead was 1.2 ppm (3.1 nmol). The radioactivity of 239Pu corresponding to 3.1 nmol is 1.7 kBq, which is lower than the radioactivity of 239Pu contaminating puncture wounds in previous severe accidents. In conclusion, the established methodology could be beneficial for future development of a method to evaluate plutonium contamination in wounds. Highlights: Methodology for evaluation of heavy-atom contamination in a wound was established. A portable X-ray fluorescence device enables on-site, rapid and direct evaluation. This method is expected to be used for evaluation of plutonium contamination in wounds.

  4. Effects of mercury on behavior and performance of northern two-lined salamanders (Eurycea bislineata)

    Energy Technology Data Exchange (ETDEWEB)

    Burke, John N.; Bergeron, Christine M.; Todd, Brian D. [Wildlife Ecotoxicology and Physiological Ecology Program, Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, 100 Cheatham Hall, Blacksburg, VA 24061 (United States); Hopkins, William A., E-mail: hopkinsw@vt.ed [Wildlife Ecotoxicology and Physiological Ecology Program, Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, 100 Cheatham Hall, Blacksburg, VA 24061 (United States)

    2010-12-15

    Mercury (Hg) causes a range of deleterious effects in wildlife, but little is known about its effects on amphibians. Our objective was to determine whether Hg affects performance and behavior in two-lined salamanders (Eurycea bislineata). We collected salamanders from Hg-contaminated and reference sites and assessed speed, responsiveness, and prey capture ability. Mercury concentrations were >17x higher in salamanders from the contaminated sites and were among the highest documented in amphibians. In the first, but not in the second, locomotion trial, we found a significant effect of Hg on speed and responsiveness. In the prey capture experiment, reference salamanders ate approximately twice as many prey items as the contaminated salamanders. Together, our results suggest that sublethal Hg concentrations may negatively affect salamanders by reducing their ability to successfully execute tasks critical to survival. Future work is warranted to determine whether Hg has other sublethal effects on salamanders and whether other amphibians are similarly affected. - Mercury contamination may alter behavior and performance in the northern two-lined salamander (Eurycea bislineata).

  5. Mercury speciation by high-performance liquid chromatography atomic fluorescence spectrometry using an integrated microwave/UV interface. Optimization of a single step procedure for the simultaneous photo-oxidation of mercury species and photo-generation of Hg0

    Science.gov (United States)

    de Quadros, Daiane P. C.; Campanella, Beatrice; Onor, Massimo; Bramanti, Emilia; Borges, Daniel L. G.; D'Ulivo, Alessandro

    2014-11-01

    We described the hyphenation of photo-induced chemical vapor generation with high performance liquid chromatography-atomic fluorescence spectrometry (HPLC-AFS) for the quantification of inorganic mercury, methylmercury (MeHg) and ethylmercury (EtHg). In the developed procedure, formic acid in mobile phase was used for the photodecomposition of organomercury compounds and reduction of Hg2 + to mercury vapor under microwave/ultraviolet (MW/UV) irradiation. We optimized the proposed method studying the influence of several operating parameters, including the type of organic acid and its concentration, MW power, composition of HPLC mobile phase and catalytic action of TiO2 nanoparticles. Under the optimized conditions, the limits of detection were 0.15, 0.15 and 0.35 μg L- 1 for inorganic mercury, MeHg and EtHg, respectively. The developed method was validated by determination of the main analytical figures of merit and applied to the analysis of three certified reference materials. The online interfacing of liquid chromatography with photochemical-vapor generation-atomic fluorescence for mercury determination is simple, environmentally friendly, and represents an attractive alternative to the conventional tetrahydroborate (THB) system.

  6. The determination of major and some minor constituents in lead zirconate-titanate compositions by x-ray fluorescence and atomic absorption spectrometry

    NARCIS (Netherlands)

    van Willigen, J.H.H.G.; Kruidhof, H.; Dahmen, E.A.M.F.

    1972-01-01

    An accurate X-ray fluorescence spectrometric method is described for the determination of lead, zirconium and titanium in lead zirconate-titanate ceramics. Careful matching of samples and standards by a borax fusion method resulted in a relative standard deviation of about 0.2% for the major

  7. The determination of major and some minor constituents in lead zirconate-titanate compositions by x-ray fluorescence and atomic absorption spectrometry

    NARCIS (Netherlands)

    Willigen, van J.H.H.G.; Kruidhof, H.; Dahmen, E.A.M.F.

    1972-01-01

    An accurate X-ray fluorescence spectrometric method is described for the determination of lead, zirconium and titanium in lead zirconate-titanate ceramics. Careful matching of samples and standards by a borax fusion method resulted in a relative standard deviation of about 0.2% for the major constit

  8. Effects of mercury on behavior and performance of northern two-lined salamanders (Eurycea bislineata).

    Science.gov (United States)

    Burke, John N; Bergeron, Christine M; Todd, Brian D; Hopkins, William A

    2010-12-01

    Mercury (Hg) causes a range of deleterious effects in wildlife, but little is known about its effects on amphibians. Our objective was to determine whether Hg affects performance and behavior in two-lined salamanders (Eurycea bislineata). We collected salamanders from Hg-contaminated and reference sites and assessed speed, responsiveness, and prey capture ability. Mercury concentrations were >17× higher in salamanders from the contaminated sites and were among the highest documented in amphibians. In the first, but not in the second, locomotion trial, we found a significant effect of Hg on speed and responsiveness. In the prey capture experiment, reference salamanders ate approximately twice as many prey items as the contaminated salamanders. Together, our results suggest that sublethal Hg concentrations may negatively affect salamanders by reducing their ability to successfully execute tasks critical to survival. Future work is warranted to determine whether Hg has other sublethal effects on salamanders and whether other amphibians are similarly affected.

  9. Accurate Atom Counting in Mesoscopic Ensembles

    CERN Document Server

    Hume, D B; Joos, M; Muessel, W; Strobel, H; Oberthaler, M K

    2013-01-01

    Many cold atom experiments rely on precise atom number detection, especially in the context of quantum-enhanced metrology where effects at the single particle level are important. Here, we investigate the limits of atom number counting via resonant fluorescence detection for mesoscopic samples of trapped atoms. We characterize the precision of these fluorescence measurements beginning from the single-atom level up to more than one thousand. By investigating the primary noise sources, we obtain single-atom resolution for atom numbers as high as 1200. This capability is an essential prerequisite for future experiments with highly entangled states of mesoscopic atomic ensembles.

  10. Accurate Atom Counting in Mesoscopic Ensembles

    Science.gov (United States)

    Hume, D. B.; Stroescu, I.; Joos, M.; Muessel, W.; Strobel, H.; Oberthaler, M. K.

    2013-12-01

    Many cold atom experiments rely on precise atom number detection, especially in the context of quantum-enhanced metrology where effects at the single particle level are important. Here, we investigate the limits of atom number counting via resonant fluorescence detection for mesoscopic samples of trapped atoms. We characterize the precision of these fluorescence measurements beginning from the single-atom level up to more than one thousand. By investigating the primary noise sources, we obtain single-atom resolution for atom numbers as high as 1200. This capability is an essential prerequisite for future experiments with highly entangled states of mesoscopic atomic ensembles.

  11. Accurate atom counting in mesoscopic ensembles.

    Science.gov (United States)

    Hume, D B; Stroescu, I; Joos, M; Muessel, W; Strobel, H; Oberthaler, M K

    2013-12-20

    Many cold atom experiments rely on precise atom number detection, especially in the context of quantum-enhanced metrology where effects at the single particle level are important. Here, we investigate the limits of atom number counting via resonant fluorescence detection for mesoscopic samples of trapped atoms. We characterize the precision of these fluorescence measurements beginning from the single-atom level up to more than one thousand. By investigating the primary noise sources, we obtain single-atom resolution for atom numbers as high as 1200. This capability is an essential prerequisite for future experiments with highly entangled states of mesoscopic atomic ensembles.

  12. Analysis of the near-resonant fluorescence spectra of a single rubidium atom localized in a three-dimensional optical lattice

    CERN Document Server

    Kim, Wookrae; Kim, Jung-Ryul; Lee, Yea-Lee; Ihm, Jisoon; An, Kyungwon

    2010-01-01

    Supplementary information is presented on the recent work by W. Kim et al. on the matter-wave-tunneling-induced broadening in the near-resonant spectra of a single rubidium atom localized in a three-dimensional optical lattice in a strong Lamb-Dicke regime.

  13. 离子色谱-氢化物发生原子荧光法测定尿中形态砷%Determination of arsenic species in urine by ion chromatography-hydride generation-atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    魏静; 梁琼; 刘俊娓

    2013-01-01

    Objective:To develop a method for the determination of arsenic species in urine by Ion chromatography - hydride Generation - atomic fluorescence spectrometry. Methods; The urine sample was filtered by 0.45 μm membrane. Using ( NH4 ) 2 HPO4 as mobile phase to explore the best ion chromatographic separation condition and the atomic fluorescence determination condition. The content of various forms of arsenic was determined by Ion chromatography - hydride Generation - atomic fluorescence spectrometry. Results; This method had good relativity and good precision(2.60% ~4. 30% ). The detection limits of As( Ⅲ), DMA, MMA and As( V ) were 2. 0 (μg/L, 4.0 μg/L,4.0 μg/L,8.0 μg/L, the average recoveries of samples were 90.48% ~ 102.90%. Conclusion; The method had the advantages of convenience, speediness, high sensitivity, less interference and high practical value without chemical pretreatment.%目的:建立离子色谱-氢化物发生原子荧光法测定尿中形态砷的方法.方法:尿样经0.45 μm滤膜过滤,以(NH4)2HPO4为流动相,采用离子色谱-氢化物发生原子荧光联机测定不同形态砷的含量.结果:实验结果相关性好,线性范围宽,精密度RSD为2.60%~4.30%,方法检出限为As(Ⅲ)2.0 μg/L,DMA4.0 μg/L,MMA4.0 μg/L,As(V)8.0 μg/L,该方法所得回收率为90.48% ~ 102.90%.结论:方法简便、快速、无需化学预处理、干扰少、灵敏度高,有较高的实用价值.

  14. X-ray fluorescence holography

    CERN Document Server

    Hayashi, K; Takahashi, Y

    2003-01-01

    X-ray fluorescence holography (XFH) is a new structural analysis method of determining a 3D atomic arrangement around fluorescing atoms. We developed an XFH apparatus using advanced X-ray techniques and succeeded in obtaining high-quality hologram data. Furthermore, we introduced applications to the structural analysis of a thin film and the environment around dopants and, discussed the quantitative analysis of local lattice distortion. (author)

  15. Influence of Two-line Emergent Floodplain Vegetation on a Straight Compound Channel Flow

    Directory of Open Access Journals (Sweden)

    Mazlin Jumain

    2013-11-01

    Full Text Available Abstract: Floods are frequent events occur in Malaysia and cause loss of life, human suffering and widespread damages to buildings, crops and infrastructure. Effort to understanding on this phenomenon is an interesting research. The objectives of this study are to determine the stage-discharge relationship, roughness coefficient and streamwise velocity distribution in a vegetated straight compound channel. The effects of two-line emergent vegetation along the edge of floodplain are studied by using a flume in the Hydraulics Laboratory, Faculty of Civil Engineering, Universiti Teknologi Malaysia (UTM. The results on stage-discharge relationship, Manning’s n and velocity distribution for overbank flows are presented in this paper. From the analysis, it is found that the vegetation influences stage-discharge where retardation of flow takes place. The maximum velocity zone is observed to be in the main channel and less fluid momentum transfer takes place in the presence of vegetation. Vegetated floodplain also influence the increases of channel roughness.

  16. Thoughts and Practice on Some Problems about Research and Application of Two-Line Hybrid Rice

    Directory of Open Access Journals (Sweden)

    Li-yun CHEN

    2011-06-01

    Full Text Available The main problems about research and application of two-line hybrid rice were reviewed, including the confusing nomenclature and male sterile lines classification, the unclear characteristics of photoperiod and temperature responses and the unsuitable site selection for male sterile line and hybrid rice seed production. In order to efficiently and accurately use dual-purpose genic male sterile lines, four types, including PTGMS (photo-thermo-sensitive genic male sterile rice, TGMS (thermo-sensitive genic male sterile rice, reverse PTGMS and reverse TGMS, were proposed. A new idea for explaining the mechanism of sterility in dual-purpose hybrid rice was proposed. The transition from sterile to fertile was involved in the cooperative regulation of major-effect sterile genes and photoperiod and/or temperature sensitive ones. The minor-effect genes with accumulative effect on sterility were important factors that affected the critical temperature of sterility transfer. In order to make better use of dual-purpose lines, the characterization of responses to photoperiod and temperature of PTGMS should be made and the identification method for the characterization of photoperiod and temperature responses of PTGMS should also be put forward. The optimal ecological site for seed production could be determined according to the historical climate data and the requirements for the meteorological conditions during the different periods of seed production.

  17. Thoughts and Practice on Some Problems about Research and Application of Two-Line Hybrid Rice

    Institute of Scientific and Technical Information of China (English)

    CHEN Li-yun; LEI Dong-yang; TANG Wen-bang; XIAO Ying-hui

    2011-01-01

    The main problems about research and application of two-line hybrid rice were reviewed,including the confusing nomenclature and male sterile lines classification,the unclear characteristics of photoperiod and temperature responses and the unsuitable site selection for male sterile line and hybrid rice seed production.In order to efficiently and accurately use dual-purpose genic male sterile lines,four types,including PTGMS (photo-thermo-sensitive genic male sterile rice),TGMS (thermo-sensitive genic male sterile rice),reverse PTGMS and reverse TGMS,were proposed.A new idea for explaining the mechanism of sterility in dual-purpose hybrid rice was proposed.The transition from sterile to fertile was involved in the cooperative regulation of major-effect sterile genes and photoperiod and/or temperature sensitive ones.The minor-effect genes with accumulative effect on sterility were important factors that affected the critical temperature of sterility transfer.In order to make better use of dual-purpose lines,the charecterization of responses to photoperiod and temperature of PTGMS should be made and the identification method for the characterization of photoperiod and temperature responses of PTGMS should also be put forward.The optimal ecological site for seed production could be determined according to the historical climate data and the requirements for the meteorological conditions during the different periods of seed production.

  18. 原子荧光光谱法测定四方金矿生活饮用水中砷含量%Determination of arsenic in drinking water Quartet Gold Atomic Fluorescence Spectrometry

    Institute of Scientific and Technical Information of China (English)

    贾书朝; 冯美云

    2014-01-01

    Arsenic is toxic to humans and other organisms carcinogenic effects, due to the toxicity of arsenic large, so the detection of arsenic in water is necessary. Through AFS-230E atomic fluorescence spectrophotometer for determination of arsenic in drinking water to ensure that our guarantee water security.%砷是对人体及其他生物体有毒害作用的致癌物质,由于砷的毒性很大,因此对水质中砷的检测是必要的。本文通过AFS-230E原子荧光分光光度仪对饮用水中砷含量测定,确保我们的保证用水安全。

  19. High performance liquid chromatography coupled to atomic fluorescence spectrometry for the speciation of the hydride and chemical vapour-forming elements As, Se, Sb and Hg: A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yuwei [Department of Chemistry and Biochemistry, Laurentian University, Ramsey Lake Road, Sudbury P3E 2C6 (Canada); Belzile, Nelson, E-mail: nbelzile@laurentian.ca [Department of Chemistry and Biochemistry, Laurentian University, Ramsey Lake Road, Sudbury P3E 2C6 (Canada); Cooperative Freshwater Ecology Unit, Laurentian University, Ramsey Lake Road, Sudbury P3E 2C6 (Canada)

    2010-06-25

    We present the most recent applications of high performance liquid chromatography (HPLC) hyphenated to hydride generation or chemical vapour generation and atomic fluorescence spectrometry (HG/CVG-AFS), for the determination and speciation of the selected hydride-forming elements arsenic (As), selenium (Se) and antimony (Sb) and the chemical vapour-forming metal Hg. The review focuses on sample preparation, post-column treatments and on the applications of this technique to various liquid and solid samples. This review also intends to discuss some limitations associated to HPLC-HG/CVG-AFS due to the necessity on post-column treatments, including the oxidation of organo-element compounds and the pre-reduction to a suitable valence. Nevertheless, the hyphenated technique HPLC-HG/CVG-AFS remains an efficient, sensitive and affordable approach to perform speciation of the four studied elements as shown by the variety of applications presented and discussed in this review.

  20. Determination of Arsenic in Matricaria chamomilla L.by microwave digestion-atomic fluorescence spectrometry%微波消解-原子荧光光谱法测定洋甘菊中砷的含量

    Institute of Scientific and Technical Information of China (English)

    辛禄德; 李强; 王建玲; 劳斐; 田树革

    2014-01-01

    Objective To develop an atomic fluorescence spectrometric method for the determination of Ar-senic in Matricaria chamomilla L.Methods Sample was digested with microwave digestion system.The Arsenic was directly analyzed by atomic fluorescence spectrometry,and the methodology of the study was investigated.Results The content of arsenic within the range of 0-10.0 μg/L the correlative coefficient of the calibration curves was over 0.999 3,the average recovery was 100.81% with RSD of 2.59% (n =6). Conclusion The method is convenient,stable,less harmful and highly sensitive.%目的:建立洋甘菊中砷含量的原子荧光光谱检测方法。方法采用微波消解样品,通过原子荧光光谱法测定洋甘菊中砷含量,并进行了方法学考察。结果砷在0~10.0μg/L (r =0.9993)范围内峰面积与浓度呈良好线性关系,平均加样回收率为100.81%,RSD=2.59%(n =6)。结论该测量方法简便、稳定、危害小、灵敏度高。

  1. Synthesis and optimization of fluorescent poly(N-isopropyl acrylamide)-coated surfaces by atom transfer radical polymerization for cell culture and detachment.

    Science.gov (United States)

    Cooperstein, Marta A; Bluestein, Blake M; Canavan, Heather E

    2014-03-16

    Although there are many stimulus-responsive polymers, poly(N-isopropyl acrylamide) (pNIPAM) is of special interest due to the phase change it undergoes in a physiologically relevant temperature range that leads to the release of cells and proteins. The nondestructive release of cells opens up a wide range of applications, including the use of pNIPAM for cell sheet and tissue engineering. In this work, pNIPAM surfaces were generated that can be distinguished from the extracellular matrix. A polymerization technique was adapted that was previously used by Mendez, and the existing protocol was optimized for the culture of mammalian cells. The resulting surfaces were characterized with X-ray photoelectron spectroscopy and goniometry. The developed pNIPAM surfaces were further adapted by incorporation of 5-acrylamidofluorescein to generate fluorescent pNIPAM-coated surfaces. Both types of surfaces (fluorescent and nonfluorescent) sustained cellular attachment and produced cellular detachment of ∼90%, and are therefore suitable for the generation of cell sheets for engineered tissues and other purposes. These surfaces will be useful tools for experiments investigating cellular detachment from pNIPAM and the pNIPAM/cell interface.

  2. Modern atomic physics

    CERN Document Server

    Natarajan, Vasant

    2015-01-01

    Much of our understanding of physics in the last 30-plus years has come from research on atoms, photons, and their interactions. Collecting information previously scattered throughout the literature, Modern Atomic Physics provides students with one unified guide to contemporary developments in the field. After reviewing metrology and preliminary material, the text explains core areas of atomic physics. Important topics discussed include the spontaneous emission of radiation, stimulated transitions and the properties of gas, the physics and applications of resonance fluorescence, coherence, cooling and trapping of charged and neutral particles, and atomic beam magnetic resonance experiments. Covering standards, a different way of looking at a photon, stimulated radiation, and frequency combs, the appendices avoid jargon and use historical notes and personal anecdotes to make the topics accessible to non-atomic physics students. Written by a leader in atomic and optical physics, this text gives a state-of-the...

  3. Determination of the electromagnetic dipole strength distribution in medium-heavy atomic nuclei by means of nuclear resonance fluorescence; Bestimmung der elektromagnetischen Dipolstaerkeverteilung in mittelschweren Atomkernen mittels Kernresonanzfluoreszenz

    Energy Technology Data Exchange (ETDEWEB)

    Massarczyk, Ralph Jens

    2011-01-17

    During the last hundred years several models were developed to describe the configuration of nuclei. These models have to make predictions, which should be comparable with experiments. As a standard type of experiment the nuclear resonance fluorescence was established. A nucleus is excited by irradiation with photons. By emitting one or more photons the nucleus decays back to the ground state. With this method it is possible to measure energy levels and to determine the strength of their excitation. A continuum of unresolved peaks gives additional strength. The existing setup at the linear electron accelerator ELBE of the Forschungszentrum Dresden-Rossendorf uses bremsstrahlung, produced as a secondary beam in a thin Niobium foil. During the years 2008/09 experiments on the nuclei of {sup 86}Kr and {sup 136}Ba took place there. In this work they will be analyzed. Photon flux and efficiency determination have been done as well as simulations on detector response and non-nuclear scattered background events. For this purpose the GEANT4 package was used. Finally the resulting cross sections were corrected for branching and feeding.

  4. Optimization of the light-induced-fluorescence signals of single atoms and efficient loading of single atoms into a magneto-optical trap%磁光阱中单原子荧光信号的优化及单原子的高效装载

    Institute of Scientific and Technical Information of China (English)

    王杰英; 刘贝; 刁文婷; 靳刚; 何军; 王军民

    2014-01-01

    In our experiment, firstly, we carry out the loading of single atoms in the magneto-optical trap (MOT) by increasing the quadrupole magnetic field gradient, improving the background vacuum, and reducing the diameters of the cooling and trapping laser beams. Secondly, we get the single atomic fluorescence signal of a high signal-to-background ratio in the MOT by means of reducing the detuning of cooling light and increasing its intensity appropriately, and using the polarization spectroscopy locking technique to suppress the fluctuations of cooling laser. In addition, with the real-time feedback on quadrupole magnetic field gradient, we demonstrate a probability of loading single atoms in the MOT as high as 98%. We also measure the statistical properties of the single atomic fluorescence which is excited by continuous light in the MOT;the measured second-order correlation is g(2)(τ =0)=0.09.%实验中首先通过增大四极磁场梯度、提高背景真空度、缩小冷却俘获激光光束直径的方法获得了磁光阱中单原子的装载.其次,通过减小冷却光失谐量、适当增加其光强、同时使用偏振光谱锁频技术抑制冷却光噪声的方法得到了磁光阱中高信号背景比的单原子荧光信号.此外,通过实时反馈控制磁光阱四极磁场梯度的方法,在实验中实现了单原子98%的装载概率.使用Hamburg Brown-Twiss 方案测量了磁光阱中的单原子在连续光激发下所辐射荧光的光子统计特性,得到二阶关联度g(2)(τ=0)=0.09.

  5. Determination of methyl mercury in fish by toluene extraction and atomic fluorescence spectrometry%甲苯萃取-原子荧光光谱法检测鱼肉中甲基汞

    Institute of Scientific and Technical Information of China (English)

    史永富; 田良良; 黄冬梅; 蔡友琼; 黄宣运; 于慧娟

    2014-01-01

    Objective To establish a method for the determination of methyl mercury in fish by toluene extraction and atomic fluorescence spectrometry (AFS). Methods Samples were digested by HBr(48%, v/v) for 30 min, and methyl mercury was extracted by methylbenzene. The extract was back-extracted into aqueous solution by Na2S2O3. The aqueous solution was ready for the analysis by atomic fluorescence spectrometry (AFS). And the present method was used to determine the concentration of methyl mercury in reference materials. Results The result was in accordance with the assigned value. Recoveries were 96.1%and 97.5% respectively. Conclusion The method is effective to determine methyl mercury in fish for its high sensitivity and reproducibility.%目的:建立甲苯萃取-原子荧光光谱检测鱼肉中甲基汞的方法。方法样品经48%氢溴酸水解、甲苯萃取、0.05 mol/L硫代硫酸钠反萃取后,应用AFS-9230原子荧光光谱法进行测定,同时经此前处理后的样品采用DMA-80直接测汞仪进行测定,与原子荧光光谱法的结果进行对比。结果原子荧光光谱法以及直接测汞仪直接测定的结果与标准物质定值吻合,确证该方法的可靠性,适用于鱼、贝等水产品中甲基汞的测定。采用该方法对鱼肉中总汞与甲基汞成分分析标准物质 GBW10029以及英国食品分析水平评估计划(food analysis performance assessment scheme, FAPAS)的罐装鱼肉样品(样品编号07189)进行了检测,检测结果与参考物定值吻合,回收率分别为96.1%,97.5%。结论该方法操作简单,灵敏度高,重现性好,适用于鱼肉中甲基汞含量的定量检测。

  6. Fluorescence spectroscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2016-01-01

    Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses...

  7. Optimize parameters of hydride generation-atomic fluorescence spectrometry for inorganic arsenic determination in grain%氢化物发生-原子荧光法测定粮食中无机砷条件的研究

    Institute of Scientific and Technical Information of China (English)

    杨庆惠

    2012-01-01

    应用氢化物发生—原子荧光分析技术进行粮食中无机砷测定的研究,通过优化酸度、硼氢化钾、载气流量、灯电流以及原子化器高度等分析条件,结果表明,砷浓度在0~30 ng/ml内呈线性关系,相关系数为0.999 9,相对标准偏差为1.6%,检出限为0.054 μg/L,用此方法测定粮食中无机砷,回收率为96.5%~103.5%.该方法简便、快速、灵敏,在实际样品测定中获得到了满意的结果,便于推广应用.%Hydride generation- atomic fluorescence spectrometry was adopted for determine the inorganic arsenic in grain. The experimental parameters such as Ph, KHB4 concentration, flow rate, lamp current and the height of atomizer were optimized. There is linear relation when the arsenic concentration was between 0~30 ng/ml with a correlation coefficient of 0. 999 9. The relative standard deviation was 1. 6%, and the detection limit was 0. 054μg/L. The recovery rate reached to 96. 5%~103. 5%. This method is simple,rapid and sensitive, and got satisfactory results in practicle,it is worth for generalize.

  8. The Determination of Arsenic in Food Additive Phosphoric Acid by Atomic Fluorescence Spectrometry%原子荧光光谱法测定食品添加剂磷酸中的砷

    Institute of Scientific and Technical Information of China (English)

    陈泉; 邵青松

    2012-01-01

    This paper established the determination of arsenic in food additive phosphoric acid by Atomic fluorescence spectrometry, and the maximum of the relative standard deviation in arsenic test is 3.07%, the recovery rate was 98.7% - 101.2%, the detection limit is 0.09 μg/L; this method is easy operation, rapid, accurate, high sensitivity, worth popularizing in terms of relatively GB3149 -2004 《food additive phosphoric acid》 national standard method for the determination of arsenic.%建立了测定食品添加剂磷酸中砷的原子荧光光谱法,测试中砷的相对标准偏差最高为3.07%,回收率在98.7%-101.2%之间、检出限为0.09μg/L;本法相对GB3149-200k4《食品添加剂磷酸》国家标准中砷的测定方法而言操作简便、快速、准确、灵敏度高,值得推广。

  9. 血液和尿液中砷的原子荧光光度测定法%Determination of arsenic in blood and urine by atom fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    徐燕

    2012-01-01

    [Objective]To explore the optimal method for determining arsenic in blood and urine. [Methods]The determination of arsenic in blood and urine was performed by microwave digest-hydride generation atom fluorescence spectrometry. [Results] Under the optimum condition, the limit of arsenic detection was 0.076 8 jJLg/L; the recoveries were 89.0-103.7% ; RSD was 2.4-5.1%. [Conclusion]The method is simple, rapid, sensitive with less interference and wide linear range.%目的 探讨血液和尿液中砷的最佳测定方法.方法 采用微波消解氢化物发生原子荧光光度法测定血液和尿液中的砷.结果 在最佳条件下砷的最低检出限为0.076 8μg/L,砷回收率为89.0%~103.7%,RSD为2.4 ~5.1%.结论 该方法具有简便,快速,灵敏度高,干扰少,线性范围宽等优点.

  10. Simultaneous determination of arsenic and mercury in polyaluminum chloride by atomic fluorescence spectrometry method%原子荧光光谱法同时测定聚氯化铝中的砷和汞

    Institute of Scientific and Technical Information of China (English)

    秦晓鹏; 吴锴; 陶福棠; 李凯

    2013-01-01

    Application of hydride generation-atomic fluorescence spectrometry method in the simultaneous determination of arsenic and mercury in polyaluminium chloride used for drinking water was studied.This method is of high sensitivity and good accuracy.Under optimal conditions,the potassium borohydride concentration,detection limit,precision,and recovery rate were investigated.Results showed:the detection limits of arsenic and mercury were 0.007 9 μg/L and 0.002 6 g/L, respectively: the recovery rates of arsenic and mercury were 93.75%~103.83% and 105.00%~108.75%, respectively.%研究了应用氢化物发生-原子荧光光谱法同时测定生活饮用水用聚氯化铝中的砷和汞,方法灵敏度高、准确度好在最佳条件下,对硼氢化钾浓度、检出限、精密度、加标回收率等进行了研究.结果表明:方法的检出限砷为0.007 9 μg/L、汞为0.002 6 μg/L,砷、汞的加标回收率分别为93.75%~103.83%和105.00%~ 108.75%.

  11. 硼氢化钾还原冷原子荧光测定大米中的汞%Determination of mercury in rice by potassium borohydride reduction cold vapor atomic fluorescence

    Institute of Scientific and Technical Information of China (English)

    毛荐; 刘忠胜

    2011-01-01

    本方法采用硝酸-过氧化氢微波消解,硼氢化钾还原冷原子荧光测定大米中的汞,消解液无需赶酸,直接测汞,方法简便快捷,实验检出限浓度为0.024μg/L,线性范围0~40 ng/ml,经国家一级标准物质验证,方法准确可靠。%This method uses nitric acid-hydrogen peroxide microwave digestion,potassium borohydride reduction of rice in cold vapor atomic fluorescence of mercury,acid digestion solution without the need to catch,direct measurement of mercury,the method is quick and easy experimental detection limit concentration of 0.024 μg / L,the linear range of 0 ~ 40 ng / ml,The method is accurate and reliable verified by the national standard.

  12. 原子荧光光谱仪测定底泥中砷含量的不确定度评定%The Uncertainty Assessment of Measuring the Arsenic Content in Sludge with Atomic Fluorescence Spectrometer

    Institute of Scientific and Technical Information of China (English)

    张俊

    2012-01-01

    This article introduces the uncertainty assessment in measuring the arsenic content in sludge with the atomic fluorescence spectrometer. The factors of uncertainty during the measurement are analyzed and identified. It presents a relatively comprehensive assessment of measurement uncertainty. According to the standard uncertainty of least squares method fitting calculation working curve, the standard uncertainty resulted from less measurements is assessed with the range method.%介绍了原子荧光光谱仪测定底泥中砷含量的不确定度评定方法,分析和识别测量过程中不确定度的来源,较为全面地评定了测量不确定度。根据最小二乘法拟合计算工作曲线的标准不确定度,采用极差法评定测量次数较少时引起的标准不确定度。

  13. Solute and solvent dynamics in confined equal-sized aqueous environments of charged and neutral reverse micelles: a combined dynamic fluorescence and all-atom molecular dynamics simulation study.

    Science.gov (United States)

    Guchhait, Biswajit; Biswas, Ranjit; Ghorai, Pradip K

    2013-03-28

    Here a combined dynamic fluorescence and all-atom molecular dynamics simulation study of aqueous pool-size dependent solvation energy and rotational relaxations of a neutral dipolar solute, C153, trapped in AOT (charged) and IGPAL (neutral) reverse micelles (RMs) at 298 K, is described. RMs in simulations have been represented by a reduced model where SPC/E water molecules interact with a trapped C153 that possesses realistic charge distributions for both ground and excited states. In large aqueous pools, measured average solvation and rotation rates are smaller for the neutral RMs than those in charged ones. Interestingly, while the measured average solvation and rotation rates increase with pool size for the charged RMs, the average rotation rates for the neutral RMs exhibit a reverse dependence. Simulations have qualitatively reproduced this experimental trend and suggested interfacial location for the solute for all cases. The origin for the subnanosecond Stokes shift dynamics has been investigated and solute-interface interaction contribution quantified. Simulated layer-wise translational and rotational diffusions of water molecules re-examine the validity of the core-shell model and provide a resolution to a debate regarding the origin of the subnanosecond solvation component in dynamic Stokes shift measurements with aqueous RMs but not detected in ultrafast IR measurements.

  14. 氢化物发生-原子荧光光谱法测定红土镍矿中砷%DETERMINATION OF ARSENIC IN LATERITE NICKEL ORES BY HYDRIDE GENERATION-ATOMIC FLUORESCENCE SPECTROMETRY

    Institute of Scientific and Technical Information of China (English)

    陈殿耿; 袁玉霞; 何飞顶

    2012-01-01

    提出了以硫脲-抗坏血酸作为还原掩蔽剂,氢化物发生-原子荧光光谱法( HG-AFS)直接测定红土镍矿中砷的方法.考察了测定的最佳条件、共存元素对测定的影响及方法的精密度和回收率.方法适用于红土镍矿中0.005%~0.1%砷的测定.%A method for the determination of arsenic in laterite nickel ores by hydride generation-atomic fluorescence spectrometry (HG-AFS) directly with thiourea-ascorbic acid hydrochloride as masking is proposed. The optimum experimental parameters, the effect of coexistent elements on the determination of arsenic, the precision and recovery of the method are investigated. The method can be applied to the determination of 0. 005% ~ 0. 1% arsenic in laterite nickel ores.

  15. 浅谈原子荧光法对测定工业污水中砷%Discussion on the Atomic Fluorescence Method for Determination of Arsenic in Industrial Waste Water

    Institute of Scientific and Technical Information of China (English)

    曾正强; 向黎黎; 姚太平

    2012-01-01

    Arsenic widely existed in the nature as a kind of very toxic elements. The main source of arsenic was the in- dustrial sewage discharged from the mining and metallurgical, chemical, pharmaceutical, textile, glass and leather manufac- turing production department, the determination of arsenic was routine laboratory item of water quality monitoring, the deter- mination of arsenic in water was summerized by the method of hydride generation - atomic fluorescence spectrometry.%砷元素作为一种毒性非常大的元素广泛的存在于自然界中。砷的主要来源是采矿冶金、化工、制药、纺织、玻璃和皮革制造等生产部门产生的工业污水,砷元素的测定是水质监测中的常规化验项目,本文对采用氢化物发生-原子荧光法测定水中的砷进行了概述。

  16. A simple and sensitive flow-injection on-line preconcentration coupled with hydride generation atomic fluorescence spectrometry for the determination of ultra-trace lead in water, wine, and rice.

    Science.gov (United States)

    Wu, Hong; Jin, Yan; Luo, Mingbiao; Bi, Shuping

    2007-09-01

    A simple and sensitive flow-injection on-line separation and preconcentration system coupled to hydride generation atomic fluorescence spectrometry (HG-AFS) was developed for ultra-trace lead determination in water, wine, and rice samples, with the salient advantages of its minimization of transition-metal interferences and tolerance to an ethanol matrix. A lead hydroxide precipitate was achieved by the on-line merging of a sample and an ammonium buffer solution and collected onto the inner walls of a knotted reactor (KR). Removal of the residual solution from KR was achieved by air flow, and dissolution of the precipitate was carried out by using 0.2 mol l(-1) HCl. With a sample consumption of 11.7 ml, an enhancement factor of 16 was obtained at a sample throughput of 30 h(-1). The limit of detection (3s) was 16 ng l(-1) and the precision (RSD) for 1.0 microg l(-1) Pb was 3.4%.

  17. 氢化物发生-原子荧光光谱法测定Inconel 718合金中痕量硒%Determination of trace selenium in 718 alloy by hydride generation-atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    向祥蓉; 刘虹; 王佼

    2012-01-01

    本文采用氢化物发生-原子荧光光谱法测定Inconel718合金中痕量硒.对影响其测定的负高压、灯电流、载气流量、屏蔽气流量、载流酸类酸度、硼氢化钾等因素进行了较为详细的研究,优化了测定条件,考察了Inconel718合金主要组成元素和基体元素对硒测定的影响.结果表明,用氟化氨溶液络合,柠檬酸溶液作干扰抑制剂能基本消除基体元素和主要组成元素的干扰.硒浓度在0~100μg/L与荧光强度有良好的线性关系,方法的检出限为0.0083μg/L.对铁镍基高温合金标准样品和Inconel 718合金样品进行9次测定,相对标准偏差为1.6%~3.5%.%In this paper a simple and fast analytical procedure for the determination of selenium in Inconel 718 alloy by hydride generation atomic fluorescence spectrometry(HG-AFS) was developed. The in fluence of instrument parameters such as voltage of PMT, current of lamp, atomizer height, carrier gas rate,shield gas rate and concentration of HCI and KBH4 on the determination of selenium were studied, and the optimized conditions were obtained. Interference of coexistent elements and methods to eliminate the interference were investigated in detail. The results showed that ammonium fluoride and citric acid mo nohydrate were the best masking. Under the optimized conditions, the linear range of selenium is 0 ~ 100μg/L, and the detection limit is 0. 0083 μg/L. The relative standard deviation is 1. 6%~3. 5%(n=9) for the standard sample and the sample of Inconel 718 alloy.

  18. Determination of arsenic and mercury in the rice by microwave digestion-atomic fluorescence spectrometry%大米中砷和汞的微波消解-原子荧光光谱测定法

    Institute of Scientific and Technical Information of China (English)

    李树雄; 张荣

    2012-01-01

    目的 建立双道原子荧光光谱法同时测定大米中的砷和汞的方法.方法 采用微波消解法处理大米样品,以原子荧光光谱法同时测定其中的砷和汞.结果 砷和汞的检出限分别为0.0044、0.039 μg/L;砷、汞标准溶液分别在1.0 ~20.0和0.10 ~1.20 μg/L范围内线性良好,其相关系数分别为0.9995、0.9992;精密度RSD:测定含2.0 μg/L砷和0.4 μg/L汞的混合标准溶液的RSD分别为2.12% 、4.59%.样品加标回收率:砷92.2% ~96.8%,汞90.3% ~92.1%.结论 该方法灵敏度、准确度高,操作方便快速,具有较低的检出限,能满足同时测定大米中砷和汞含量的测定工作.%[Objective ] To establish the method for simultaneous determination of trace arsenic and mercury in rice by dual-channel atomic fluorescence spectrometry. [Methods] The rice samples was digested by microwave, then the trace arsenic and mercury were simultaneously determined by Atomic fluorescence spectrometry. [ Results] The detection limits were 0.004 4 (μg/L for arsenic and 0.039 (μg/L for mercury; there was a linear relationship between 1.0-20.0 μg/L of arsenic standard solution, 0.10-1.20 (μg/L of mercury standard solution. The correlation coefficients were 0.999 5 for arsenic and 0.999 2 for mercury. The precision RSD was 2.12% for 2.0 μg/L arsenic mixed standard solution, and 4.59% for 0.4 μg/L mercury mixed standard solution. The recoveries were 92.2%-96.8% for arsenic and 90.3%-92.1% for mercury. [Conclusion]This method is very sensitive, with high accuracy, easy and fast. It has lower detecting limit, and can determine the content of Arsenic and Mercury in rice simultaneously

  19. 氢化物发生原子荧光光谱法测量化妆品中Sb的价态%Valent speciation analysis of antimony in cosmetics by hydride generation atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    肖融; 张新智; 王昌钊; 冯礼; 秦德元; 刘霁欣

    2012-01-01

    考察了NaF、8-羟基喹啉、柠檬酸对Sb(Ⅲ)和Sb(V)原子荧光信号的掩蔽作用和还原解柠檬酸除掩蔽作用的方法.结果表明,0.10mol/L柠檬酸对Sb(V)掩蔽作用最强,且对Sb(Ⅲ)有增敏作用,最适于作为Sb价态测量的掩蔽剂,而10g/L碘化钾(KI)+ 10g/L硫脲(Tu)可在5h内完全解除柠檬酸对Sb(V)的掩蔽作用.据此建立了化妆品中Sb价态的非色谱氢化物发生原子荧光测量方法.样品经0.10mol/L柠檬酸提取两次后,离心去上清液,合并定容,得到提取液;提取液酸化后直接测得Sb(Ⅲ)含量;提取液酸化并加入KI+Tu,放置5h以上后可测得Sb(V)与Sb(Ⅲ)的含量和,此值减去Sb(Ⅲ)含量可得Sb(V)含量.计算表明,该方法对Sb(Ⅲ)和Sb(V)的检出限(3σ)均为0.32μg/L,定量限(3σ)均为1.0μg/L.对实际化妆品作了测量,Sb(Ⅲ)和Sb(V)的加标回收率在70%~130%之间.实验中存在少量Sb(Ⅲ)到Sb(V)的转化.%The masking effects of NaF, 8-hydroxygquinoline and citric acid on the atomic fluorescence signals of Sb(Ⅲ ) and Sb( V ) And the method for eliminating the masking effect of citric acid were investigated. The results show that 0. 10 mol/L citric acid has the strongest masking effect on Sb(V) and can increase the sensitivity of Sb(Ⅲ) , and l0g/L KI+l0g/L thiourea can completely eliminate the masking effect of citric acid in >5h. Based on this, a method for analyzing the valent speciation of Sb in cosmetics by hydride generation atomic fluorescence spectrometry (HGAFS) was developed. The samples were extracted twice with 0. L0ml/L citric acid. The supernatant was removed by centrifugation and the residues were merged asextract solution. After the acidification of the extract solution, the Sb(Ⅲ) content was determined directly. Then the extract solution was added with KI (10g/L)+ thiourea (l0g/L) and set aside for >5h before the total content of Sb(V) and Sb(Ⅲ) was determined. The Sb( V) content was obtained by subtracting Sb

  20. Simultaneous Determination of Arsenic and Antimony in Water by Hydride Generation-Atomic Fluorescence Spectrometry%氢化物发生-原子荧光光谱法同时测定水中砷和锑

    Institute of Scientific and Technical Information of China (English)

    黄选忠; 万忠卫; 杜宏山; 郑丽

    2013-01-01

    建立在硝酸介质中用氢化物发生-原子荧光光谱法同时测定水中砷和锑的方法。优化了仪器工作条件、酸度、硼氢化钾及还原剂浓度。砷、锑的线性范围为0~10.0µg/L;检出限分别为0.02,0.01µg/L;测定结果的相对标准偏差分别为1.77%~3.72%,2.95%~4.87%(n=6);加标回收率分别为98%~106%,96%~105%。该法操作简便,灵敏度高,快速,便于推广,适用于水中砷和锑的同时测定。%The method for simultaneous determination of arsenic and antimony in water was established by hydride-generation atomic fluorescence spectrometry in nitric acid medium. Instrument condition,acidity,concentration of potassium borohydride and thiourea-ascorbic acid were selected. The linear relationship of arsenic and antimony was 0-10.0 µg/L. The detection limit of arsenic and antimony was 0.02 µg/L and 0.01 µg/L, the relative standard deviation of arsenic and antimony determination results was 1.77%-3.72%and 2.95%-4.87%(n=6) , the recovery of standard addition of arsenic and antimony was 98%-106%and 96%-105%respectively. This method has the advantages of simple operation and high sensitivity,it is rapid and easy to spread,which is suitable for simultaneous determination of arsenic and antimony in water.

  1. Optimization of Atomic Fluorescence Determination of Arsenic and Mercury in Leather%原子荧光光谱法测定皮革中砷和汞的条件优化

    Institute of Scientific and Technical Information of China (English)

    余红

    2012-01-01

    用硝酸、过氧化氢微波消解处理皮革样品,获得均匀的样品消解液。用原子荧光光谱法测定皮革中的砷和汞,并优化了测定条件。砷的相对标准偏差≤3.8%,方法检出限为0.0376μg/L,回收率为97.8%~102.8%;汞的相对标准偏差为≤7.2%,方法检出限为0.0046μg/L,回收率为95.0%-103.0%。%A uniform leather sample digestion solution was obtained firstly with the microwave digestion treatment method using nitric acid and hydrogen peroxide, and then the conditions for detecting Arsenic and Mercury in leather using atomic fluorescence method were optimized. The results indicated that the relative standard deviation was not greater than 3.8%, the detection limit was 0.0376 μg/L, the recovery rate was 97.8%-102.8% for Arsenic; and the relative standard deviation was not greater than 7.2%, the detection limit was 0.0046 μg/L, the recovery rate was 95.0%-103.0% for Mercury.

  2. Determination of arsenic and hydrargyrum in cosmetics by using Hydride atomic fluorescence spectroscopy%氢化物原子荧光光谱法测化妆品中的砷、汞

    Institute of Scientific and Technical Information of China (English)

    李淑娜

    2012-01-01

    目的:建立化妆品中准确测定砷、汞的测定方法.方法:采用HNO3-H2SO4混合酸消化化妆品、氢化物发生原子荧光光谱法测定砷、汞的含量.结果:砷的方法检出限为0.0227 μg/g,测定精密度为0.9%~1.4%,回收率为96.0% ~ 102.7%,汞的方法检出限为0.171 ng/g,测定精密度为1.4% ~2.0%,回收率为90.0% ~ 105.0%.结论:该方法精密度好,回收率及灵敏度高,线性范围宽,可作为化妆品中微量砷、汞的测定方法.%Objective: To establish the method for accurate determination of arsenic and hydrargyrum in cosmetics. Methods: The contents of arsenic and hydrargyrum were determined by using mixed acid H2SO4 - HNO3 digestion cosmetics and hydride generation atomic fluorescence spectroscopy. Results: The detection limit of arsenic was 0.0227 μg/g, the measuring precision was 0.9% ~ 1.4% , and the recovery rate was 96.0% ~ 102. 7% . The detection limit of hydrargyrum was 0. 171 ng/g, the measuring precision was 1.4% ~2.0%, and the recovery rate was 90. 0% ~105.0%. Conclusion; The method could be used to determine the trace arsenic and hydrargyrum in cosmetics, with good precision, high recovery rate and sensitivity and wide linear range.

  3. Speciation of the immediately mobilisable As(III), As(V), MMA and DMA in river sediments by high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry following ultrasonic extraction

    Energy Technology Data Exchange (ETDEWEB)

    Huerga, A. [Departamento de Quimica Analitica y Alimentaria, Area de Quimica Analitica, Facultad de Ciencias (Quimica), Universidad de Vigo, As Lagoas-Marcosende s/n, 36200 Vigo (Spain); Lavilla, I. [Departamento de Quimica Analitica y Alimentaria, Area de Quimica Analitica, Facultad de Ciencias (Quimica), Universidad de Vigo, As Lagoas-Marcosende s/n, 36200 Vigo (Spain); Bendicho, C. [Departamento de Quimica Analitica y Alimentaria, Area de Quimica Analitica, Facultad de Ciencias (Quimica), Universidad de Vigo, As Lagoas-Marcosende s/n, 36200 Vigo (Spain)]. E-mail: bendicho@uvigo.es

    2005-04-04

    In this work, a fast method is developed for the speciation of As(III), As(V), MMA and DMA in the immediately mobilisable fraction of river sediments (i.e. water-soluble and phosphate-exchangeable) by high performance liquid chromatography-hydride generation-atomic fluorescence detection (HPLC-HG-AFD) after extraction using focused ultrasound. The influence of relevant parameters influencing an ion-pairing chromatographic separation following isocratic elution (i.e. amount of MeOH in the mobile phase, ion pair reagent concentration, pH, flow rate) was studied. Focused ultrasound transmitted from an ultrasonic probe provided the same extractable contents as conventional extraction with no changes in the species distribution. The effect of the drying step over extraction of As species was investigated. The following drying procedures were compared: freeze-, oven-, microwave- and air-drying. No influence of the drying operation on the water-extractable fraction was observed. However, freeze- and air-drying yielded significantly higher phosphate-extractable amounts of As(III) and As(V) as compared to oven and microwaves. Detection limits for the As species were in the range 1.3-4.1 ng/g for the water-soluble fraction and 1.6-4.8 ng/g for the phosphate buffer exchangeable fraction. The method was applied to the speciation of immediately mobilisable As(III), As(V), DMA and MMA in 11 sediment samples collected along the beds of the Louro River (southern Galicia, Spain)

  4. Determination of Se in Saffron by Using Hydride Generation Atomic Fluorescence Spectrometry%氢化物发生原子荧光光谱法测定西红花柱头中的硒

    Institute of Scientific and Technical Information of China (English)

    张宏; 张新申; 颜钫; 陈放

    2001-01-01

    A method for determination of Se in saffron using AFS-230 hydride generation atomic fluorescence spectrometry was introduced.Detections were completed made in every possible best condition.The optimal analytical conditions in HClO4-HNO3 were examined.The detection limit is 0.5μg/L.The linear range is 1.5~15.0 μg/L.The correlation coefficient is 0.9999,and the recovery rate is about 90%~97%.Se of saffrons from 4 regions was determined by standard curve method.The experiment results show that this method has low detection limit,high accurate,simple operation,fast and low cost.It's easy to be spread.%应用AFS-230型双道原子荧光光谱计进行了氢化物发生原子荧光光谱法测定西红花柱头中硒的研究,方法中采用硝酸做介质,并对各种最佳分析条件进行了测定。线性范围为1.5~15μg/L,相关系数R=0.9999,回收率为90%~97%。采用标准曲线法对4种不同产地的西红花干燥柱头中硒进行了测定。该方法操作简单、快速,精密度好,准确性高,检出限较低,经济,便于推广应用。

  5. Simultaneous speciation of inorganic arsenic and antimony in water samples by hydride generation-double channel atomic fluorescence spectrometry with on-line solid-phase extraction using single-walled carbon nanotubes micro-column

    Energy Technology Data Exchange (ETDEWEB)

    Wu Hong, E-mail: wuhong1968@hotmail.com; Wang Xuecui; Liu Bing; Liu Yueling; Li Shanshan; Lu Jusheng; Tian Jiuying; Zhao Wenfeng; Yang Zonghui

    2011-01-15

    A new method was developed for the simultaneous speciation of inorganic arsenic and antimony in water by on-line solid-phase extraction coupled with hydride generation-double channel atomic fluorescence spectrometry (HG-DC-AFS). The speciation scheme involved the on-line formation and retention of the ammonium pyrrolidine dithiocarbamate complexes of As(III) and Sb(III) on a single-walled carbon nanotubes packed micro-column, followed by on-line elution and simultaneous detection of As(III) and Sb(III) by HG-DC-AFS; the total As and total Sb were determined by the same protocol after As(V) and Sb(V) were reduced by thiourea, with As(V) and Sb(V) concentrations obtained by subtraction. Various experimental parameters affecting the on-line solid-phase extraction and determination of the analytes species have been investigated in detail. With 180 s preconcentration time, the enrichment factors were found to be 25.4 for As(III) and 24.6 for Sb(III), with the limits of detection (LODs) of 3.8 ng L{sup -1} for As(III) and 2.1 ng L{sup -1} for Sb(III). The precisions (RSD) for five replicate measurements of 0.5 {mu}g L{sup -1} of As(III) and 0.2 {mu}g L{sup -1} of Sb(III) were 4.2 and 4.8%, respectively. The developed method was validated by the analysis of standard reference materials (NIST SRM 1640a), and was applied to the speciation of inorganic As and Sb in natural water samples.

  6. Determination of trace germanium in health protection food by hydride generation atomic fluorescence spectrometry%氢化物-原子荧光光谱法测定保健食品中痕量锗

    Institute of Scientific and Technical Information of China (English)

    宋伟明; 倪刚; 胡奇林; 全晓塞

    2001-01-01

    A new method was introduced for the determination of trace germanium by hydride generation atomic fluorescence spectrometry(HGAFS).The effect of the medium amounts of acid, action of hydride and screening agent of the determination of germanium was investigated. The operating condition of the instrument was optimized. The interference from foreign ions was eliminated by adding phosphoric acid and tartaric acid. This method was applied to the determination of germanium in some health protection and nourishing food. The detection limit (3δ) is 6.2 ng/g with a RSD of 5% .The recovery of standard addition is in 95%~105%.%提出了以氢化物-原子荧光光谱法测定保健食品中锗的新方法,研究了酸介质、氢化物发生、增敏掩蔽剂等因素对测定的影响,并选择出仪器的最佳工作条件;采用磷酸-酒石酸介质进行测定,不但可有效消除共存离子的干扰,而且起到增敏作用,方法的检出限为6.2,ng/g,相对标准偏差(RSD)在5%以内,加标回收率为95%~105%,结果令人满意.

  7. Preliminary results on the determination of ultratrace amounts of cadmium in tea samples using a flow injection on-line solid phase extraction separation and preconcentration technique to couple with a sequential injection hydride generation atomic fluorescence spectrometry.

    Science.gov (United States)

    Duan, Taicheng; Song, Xuejie; Jin, Dan; Li, Hongfei; Xu, Jingwei; Chen, Hangting

    2005-10-31

    In this work, a method was developed for determination of ultra-trace levels of Cd in tea samples by atomic fluorescence spectrometry (AFS). A flow injection solid phase extraction (FI-SPE) separation and preconcentration technique, to on-line couple with a sequential injection hydride generation (SI-HG) technique is employed in this study. Cd was preconcentrated on the SPE column, which was made from a neutral extractant named Cyanex 923, while other matrix ions or interfering ions were completely or mostly separated off. Conditions for the SPE separation and preconcentration, as well as conditions for the HG technique, were studied. Due to the separation of interfering elements, Cd hydride generation efficiency could be greatly enhanced with the sole presence of Co(2+) with a concentration of 200mugL(-1), which is much lower than those in other works previously reported. Interferences on both the Cd separation and preconcentration, and Cd hydride generation (HG) were investigated; it showed that both the separation and preconcentration system, and the HG system had a strong anti-interference ability. The SPE column could be repeatedly used at least 400 times, a R.S.D. of 0.97% was obtained for 6 measurements of Cd with 0.2mugL(-1) and a correlation coefficiency of 1.0000 was obtained for the measurement of a series of solutions with Cd concentrations from 0.1 to 2mugL(-1). The method has a low detection limit of 10.8ngL(-1) for a 25mL solution and was successfully validated by using two tea standard reference materials (GBW08513 and GBW07605).

  8. Analysis of Selenium in Blood of Patients with Lung Cancer by Microwave Digestion-Atomic Fluorescence Spectrometry%微波消解-原子荧光光谱法分析肺癌患者全血中硒

    Institute of Scientific and Technical Information of China (English)

    董琳; 张欣欣; 王继灵; 吴桂平; 杨庆斌

    2014-01-01

    目的:探讨肺癌患者血样中硒含量的变化。方法采集肺癌组和对照组血样,用硝酸、过氧化氢混合液微波消解样品,采用原子荧光光谱法测定血样中硒的含量。结果肺癌组和对照组硒平均质量浓度分别为0.087、0.123 mg/L。结论肺癌患者血样硒含量明显降低,缺硒可能是导致肺癌高发的重要因素。%Objective The paper investigates the change of the selenium content in the blood samples of patients with lung cancer .Methods The writer applies miscible liquids of nitric acid and hydrogen peroxide to the digestion of the collected blood samples from lung cancer group and the control group , using atomic fluorescence spectrometry to determine the content of selenium in blood samples .Results The average content of selenium in the lung cancer group and control group in average content of selenium are 0.087 mg/L and 0.123 mg/L respectively .Conclusion The content of selenium significantly lowered in the blood samples collected from patients with lung cancer .Selenium deficiency may be an important factor leading to high incidence of lung cancer .

  9. Determination of Arsenic and Mercury in Soil by Atomic Fluorescence Spectrometry with Aquafortis Bath Digestion%王水消解-原子荧光光谱法测定土中砷和汞

    Institute of Scientific and Technical Information of China (English)

    杜英秋

    2013-01-01

    To explore new methods of determinating arsenic and mercury in soil ,through atomic fluorescence spectrometry with aquafortis digestion ,arsenic and mercury in soil samples were determinated .The results showed that good linear relationship when concentrations of arsenic was 0~100 ng·mL-1 and mercury was 0~2 .0 ng·mL-1 ,the correlation coefficient were 0 .999 9 and 0 .999 3 respectively ,the detection limits were 0 .260 and 0 .022 ng·mL-1 ,the method was used for the determination of arsenic and mercury in different soil standard materials ,results were in the standard value range ,RSD was 1 .3% ~3 .5% ,that indicatd that the method had wide linear range ,good stability ,high sensitivity ,high accuracy and it could be widely used for the determina-tion of arsenic and mercury in bulk soil samples .%为探讨检测土壤中砷和汞的新方法,采用王水-水体系进行消解,应用原子荧光光谱法对土壤样品中的砷和汞进行测定。结果表明:当砷的质量浓度处于0~100.0 ng·mL-1,汞的质量浓度处于0~2.0 ng·mL-1时,浓度与荧光强度均能呈良好的线性关系,相关系数分别为0.9999和0.9993,方法的检出限分别为0.260和0.022 ng·mL-1,将该方法用于不同土壤标准物质的测定,测定结果均在标准值允许范围内,RSD处于1.3%~3.5%,说明该方法线性范围宽,稳定性好,灵敏度高,准确度高,可广泛用于批量土样中砷和汞的测定。

  10. Simultaneous determination of arsenic and antimony in water by hydride generation-atomic fluorescence spectrometry%同时测定水中砷和锑的氢化物发生-原子荧光光谱法

    Institute of Scientific and Technical Information of China (English)

    宋岳; 周虹

    2012-01-01

    目的 建立双道原子荧光光度计同时测定饮用水中砷和锑的方法,以提高工作效率.方法 选择最佳的仪器条件,进行样品处理方法及酸度、硼氢化钾浓度、检出限、线性范围、精密度、加标回收率等研究.结果 该方法线性关系:砷为0 ~ 80 μg/L,锑为O~40μg/L.检出限:砷为0.087 μg/L,锑为0.19μg/L.相对标准偏差:砷为1.93% ~ 2.55%;锑为1.97% ~3.02%.平均加标回收率:砷为95.7%;锑为96.5%.结论 该方法操作简便,灵敏度高,快速,便于推广,适用于水中砷和锑的同时测定.%[ Objective]To establish the method for simultaneous determination of arsenic and antimony in drinking water by double channel atomic fluorescence spectrometer, improve work efficiency. [Methods]Choosing optimal instrument condition, the sample treatment method, acidity, concentration of potassium borohydride, detection limit, linear range, precision and the recovery of standard addition were studied. [Results]The linear relationship of arsenic and antimony was 0-80μg/L and 0-40 μg/L respectively. The detection limit of arsenic and antimony was 0.087 μg/L and 0.19 μg/L respectively. The relative standard deviation of arsenic and antimony was 1.93% -2. 55% and 1. 97% -3. 02% respectively. The average recovery of standard addition of arsenic and antimony was 95.7% and 96.5% respectively. [ Conclusion] This method has the advantages of simple operation and high sensitivity , it is rapid and easy to spread, which is suitable for simultaneous determination of arsenic and antimony in water.

  11. Determination of arsenic in urine by wet digestion-hydride generation atomic fluorescence spectrometry%湿法消化-氢化物原子荧光法测定尿中砷

    Institute of Scientific and Technical Information of China (English)

    张克梅; 王文静

    2011-01-01

    Objective: To establish an accurate and simple determination of universal detection of arsenic in urine. Methods:Mixed acid sample digestion in the electric panel heating with thiourea, ascorbic acid to pentavalent arsenic to trivalent arsenic pre -reduction, and then potassium borohydride as reducing agent, to 5% HNO3 as the medium, with the AFS-230E direct determination of atomic fluorescence spectrometer. Results: The optimal experimental conditions, good linearity was presented within the arsenic concentration range of 0.0 μg/L ~ 20.0 μg/L; and the correlation coefficient was 0.9999, the lowest detection limit of the method was 0. 164 μg/L, relative standard deviation (RSD) was 0.4% ~ 1.2%, the recovery was 98.6% ~103.5%. Conclusion: The method is simple, precise, which high recovery rate, which is to determine a reliable method ofurinary arsenic.%目的:建立一种准确简单易于普及的测定尿中砷的检测方法.方法:样品用混合酸在电热板上加热消解后,用硫脉抗坏血酸将五价砷预还原为三价砷,再用硼氢化钾作还原剂,以5% HNO3为介质,用AF5-230E原子荧光光度计直接测定.结果:在最佳实验条件下,砷的浓度在0.0 μg/L~20.0 μg/L之间线性关系良好,相关系数r= 0.9999,方法的最低检出限为0.164 μg/L,RSD为0.4%~1.2%,加标回收率为98.6%~103.5%.结论:该方法操作简单,精密度好,回收率高,是测定尿砷含量的可靠方法.

  12. Nondestructive characterization of municipal-solid-waste-contaminated surface soil by energy-dispersive X-ray fluorescence and low-Z (atomic number) particle electron probe X-ray microanalysis.

    Science.gov (United States)

    Gupta, Dhrubajyoti; Ghosh, Rita; Mitra, Ajoy K; Roy, Subinit; Sarkar, Manoranjan; Chowdhury, Subhajit; Bhowmik, Asit; Mukhopadhyay, Ujjal; Maskey, Shila; Ro, Chul-Un

    2011-11-01

    The long-term environmental impact of municipal solid waste (MSW) landfilling is still under investigation due to the lack of detailed characterization studies. A MSW landfill site, popularly known as Dhapa, in the eastern fringe of the metropolis of Kolkata, India, is the subject of present study. A vast area of Dhapa, adjoining the current core MSW dump site and evolving from the raw MSW dumping in the past, is presently used for the cultivation of vegetables. The inorganic chemical characteristics of the MSW-contaminated Dhapa surface soil (covering a 2-km stretch of the area) along with a natural composite (geogenic) soil sample (from a small countryside farm), for comparison, were investigated using two complementary nondestructive analytical techniques, energy-dispersive X-ray fluorescence (EDXRF) for bulk analysis and low-Z (atomic number) particle electron probe X-ray microanalysis (low-Z particle EPMA) for single-particle analysis. The bulk concentrations of K, Rb, and Zr remain almost unchanged in all the soil samples. The Dhapa soil is found to be polluted with heavy metals such as Cu, Zn, and Pb (highly elevated) and Ti, Cr, Mn, Fe, Ni, and Sr (moderately elevated), compared to the natural countryside soil. These high bulk concentration levels of heavy metals were compared with the Ecological Soil Screening Levels for these elements (U.S. Environment Protection Agency) to assess the potential risk on the immediate biotic environment. Low-Z particle EPMA results showed that the aluminosilicate-containing particles were the most abundant, followed by SiO2, CaCO3-containing, and carbonaceous particles in the Dhapa samples, whereas in the countryside sample only aluminosilicate-containing and SiO2 particles were observed. The mineral particles encountered in the countryside sample are solely of geogenic origin, whereas those from the Dhapa samples seem to have evolved from a mixture of raw dumped MSW, urban dust, and other contributing factors such as wind

  13. Determination of Arsenic and Antimony in Leather by Atomic Fluorescence Spectrometry with Microwave Digestion%微波消解—原子荧光光谱法同时测定皮革中的砷和锑

    Institute of Scientific and Technical Information of China (English)

    吕小园; 陈新焕; 肖家勇; 刘正华; 陈练; 杨万彪; 黄红; 张志荣

    2012-01-01

    建立了皮革及其制品中砷和锑的微波消解-原子荧光光谱测定方法,方法准确、灵敏,快速.在优化的试验条件下,砷浓度在0.5~150 ng/mL范围内成线性关系,相关系数r=0.9995,检出限为0.22 ng/mL,回收率为99.4%~104.2%:锑浓度在0.5~ 120 ng/mL范围内成线性关系,相关系数r=0.9998,检出限为0.16 ng/mL,回收率为101.1%~106.7%.相对标准偏差(n=5)均小于5%.方法应用于皮革及其制品中砷和锑的测定,结果满意.%An accurate, sensitive and quick method for determination of arsenic and antimony in leather by atomic fluorescence spectrometry with microwave digestion was developed in this paper. Under the optimized condition, the result of arsenic showed that the linear range was 0.5 - 150 ng/mL(r =0. 9995), the limit of detection was 0. 22 ng/mL, and the average recoveries in leather ranged form 99. 4% to 104. 2% . The linear range of antimony was 0. 5 ~ 120 ng/mL( r = 0.9998) , the limit of detection was 0. 16 ng/mL, the average recoveries ranged form 101. 1% tol06.7%. TheRSD(n=5) were all lower than 5%. It has been applied to routine determination of arsenic and antimony in leather with satisfactory results.

  14. Determination of Inorganic Arsenic in Atmospheric Particles by Hydride Generation-atomic Fluorescence Spectrometry%氢化物发生-原子荧光光谱法测定大气颗粒物中的砷形态

    Institute of Scientific and Technical Information of China (English)

    梁淑轩; 吴虹; 齐学先; 郑璇; 何晓娇

    2011-01-01

    Concentration of atmospheric particles is one of the atmospheric pollution indicators. Heavy metals in the atmospheric particles can risk for human health in both direct and indirect way. Arsenic is one of the higher metal content in them. The inorganic compounds are far more toxic than their organic metabolites. In this paper, the hydride generation atomic fluorescence spectrometric method was employed to the determination of As ( Ⅲ ) and As (V) in the Atmospheric particles. The amount of reducing agent,acid medium and its acidity, carrier gas and shield gas flow rate and observation height of the fluorescence intensity were investigated, and the interference experiment was carried out for concomitant elements. In the best conditions, the detection limit was 0. 34 μg/L, the recovery ranged from 98.18% ~ 102.54%,and the relative standard deviation was about 0.8%. The method was featured by easy operation, fast speed and it has been applied to the analysis of arsenic in the particles with satisfactory results.%采用氢化物发生原子荧光法直接测定不同粒径大气颗粒物中As(Ⅲ)和As(Ⅴ)的含量.研究了还原剂用量、酸介质及其酸度、载气及屏蔽气流量和观测高度等对荧光强度的影响,探讨了共存离子对砷测定的干扰.在选定的最佳条件下,得到检出限为0.34μg/L,方法检出限为0.21μg/g,加标回收率为98.18%~102.54%,相对标准偏差为0.8%左右.用该方法测定大气颗粒物中不同形态的砷,操作简便,快速,灵敏度高.

  15. Study of ripple-trapped proton behaviour in LHD by two line-of-sight measurements of fast neutrals

    Science.gov (United States)

    Saida, T.; Sasao, M.; Isobe, M.; Krasilnikov, A. V.; Kumazawa, R.; Mutoh, T.; Watari, T.; Seki, T.; Saito, K.; Murakami, S.; Matsuoka, K.; LHD Experimental Group

    2004-04-01

    The behaviour of helical ripple-trapped particles in large helical device (LHD) have been investigated by two line-of-sights natural diamond detector measurements in plasma sustained with ICRF for two types of resonance configurations, i.e. on-axis and saddle-shaped resonances. The tail temperature increases linearly as the Stix-temperature increases and then saturation follows, indicating the effect of the finite confinement time of the energetic ions. In the linear region, the tail readily increases when the line-of-sight is focused on the larger resonance area. The confinement time of the energetic ions is obtained from the empirical relation based on the Stix theory. The configuration with a saddle-shaped resonance has a longer confinement time than the on-axis resonance. Analyses of experimental measurements are consistent with the theoretical calculations including collisional ripple-induced transport.

  16. Insulin regulates lipid and glucose metabolism similarly in two lines of rainbow trout divergently selected for muscle fat content.

    Science.gov (United States)

    Jin, Junyan; Panserat, Stéphane; Kamalam, Biju Sam; Aguirre, Peyo; Véron, Vincent; Médale, Françoise

    2014-08-01

    Two experimental rainbow trout lines were developed through divergent selection for low (Lean 'L' line) or high (Fat 'F' line) muscle fat content. Previous nutritional studies suggested that these lines differed in their regulation of lipid and glucose metabolism. Since insulin acts as an anabolic hormone by regulating lipid and glucose metabolism, we put forward the hypothesis that F line might have a stronger sensitivity to insulin than L line. In order to test this hypothesis, bovine insulin was injected into rainbow trout of the two lines fasted for 48 h. As expected, insulin induced hypoglycemia and activated Akt-TOR signaling both in the liver and muscle of the two lines. We demonstrate that this was coupled with increased expression of insulin dependent glucose transporter (GLUT4) and transcription factors of fatty acid anabolism (LXR and SREBP1c) in the muscle and liver, respectively, and lower mRNA levels of fatty acid oxidation enzymes (CPT1a, CPT1b and HOAD) in the white muscle of both lines. Regarding the genotype effect, TOR signaling response to insulin was stronger in F line as reflected by the higher phosphorylation of S6 protein and elevated mRNA levels of lipogenic enzyme (FAS) in the liver of F line. This observation was concordant with the higher plasma concentrations of free fatty acids and triglycerides in F line. Moreover, mRNA levels of hepatic gluconeogenic enzymes (G6Pase2, FBPase and PEPCK) and muscle fatty acid oxidation enzymes (CPT1a, CPT1b, HOAD and ACO) were higher in the F line. However, very few insulin-genotype interactions were detected, indicating that insulin induced similar changes in lipid and glucose metabolism in both lines. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Atomic energy

    CERN Multimedia

    1996-01-01

    Interviews following the 1991 co-operation Agreement between the Department of Atomic Energy (DAE) of the Government of India and the European Organization for Nuclear Research (CERN) concerning the participation in the Large Hadron Collider Project (LHC) . With Chidambaram, R, Chairman, Atomic Energy Commission and Secretary, Department of Atomic Energy, Department of Atomic Energy (DAE) of the Government of India and Professor Llewellyn-Smith, Christopher H, Director-General, CERN.

  18. Atom chips

    CERN Document Server

    Reichel, Jakob

    2010-01-01

    This book provides a stimulating and multifaceted picture of a rapidly developing field. The first part reviews fundamentals of atom chip research in tutorial style, while subsequent parts focus on the topics of atom-surface interaction, coherence on atom chips, and possible future directions of atom chip research. The articles are written by leading researchers in the field in their characteristic and individual styles.

  19. Atomic polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Safronova, M. S. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Mitroy, J. [School of Engineering, Charles Darwin University, Darwin NT 0909 (Australia); Clark, Charles W. [Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, Maryland 20899-8410 (United States); Kozlov, M. G. [Petersburg Nuclear Physics Institute, Gatchina 188300 (Russian Federation)

    2015-01-22

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.

  20. Ultracold atoms on atom chips

    DEFF Research Database (Denmark)

    Krüger, Peter; Hofferberth, S.; Haller, E.

    2005-01-01

    Miniaturized potentials near the surface of atom chips can be used as flexible and versatile tools for the manipulation of ultracold atoms on a microscale. The full scope of possibilities is only accessible if atom-surface distances can be reduced to microns. We discuss experiments in this regime...

  1. Cytodynamics of the immune response in two lines of mice genetically selected for "high" and "low" antibody synthesis.

    Science.gov (United States)

    Biozzi, G; Stiffel, C; Mouton, D; Bouthillier, Y; Decreusefond, C

    1972-05-01

    Two lines of mice have been separated by selective breeding for the character "agglutinin production to heterologous erythrocytes." Around the 18th generation of selection the two lines could be considered as homozygous for the character investigated. This trait is under the control of a group of additive genes. The interline difference in the production of anti-SE agglutinins was verified for the range of antigen doses from subimmunogenic to maximal. After intravenous immunization with an optimal dose of SE, the duration of the exponential rise in serum antibody was 4-5 days in both lines. At this time most of the interline difference in responsiveness is already expressed. A cytodynamic study carried out in terms of plaque-forming cells (PFC) and rosette-forming cells (RFC) in the spleen during the exponential phase showed that the principal interline difference is found in the doubling time of cells engaged in the immune response. More precise cytodynamic analysis made in terms of RFC showed that the doubling time of RFC is 9 hr in high responder and 16 hr in low responder mice. The duration of the exponential rise and the number of target cells stimulated by antigen is the same in both lines. The interline difference at the end of the exponential rise (4 days postimmunization) is larger in terms of serum antibody (30-40-fold) than in terms of PFC or RFC (20- and 11-fold, respectively). A morphological study of RFC in nonimmunized mice showed that about 90% of rosettes were formed by small lymphocytes in both lines. The remainder were medium-sized lymphocytes. At the peak of the cellular response the RFC have differentiated into large lymphocytes, blast cells, and plasma cells. The contribution of plasma cells to RFC is much greater in the high than in the low line. The cytodynamic and morphologic results presented in this article are compatible with the hypothesis that the group of genes segregated in each line during the selective breeding control and regulate

  2. Fluorescent microspheres

    Science.gov (United States)

    Rembaum, A.

    1978-01-01

    Latex particles with attached antibodies have potential biochemical and environmental applications. Human red blood cells and lymphocytes have been labeled with fluorescent microspheres by either direct or indirect immunological technique. Immunolatex spheres can also be used for detecting and localizing specific cell surface receptors. Hormones and toxins may also be bondable.

  3. 氢化物原子荧光光谱法同时测定生活饮用水中砷和硒%Simulatneous Determination of Arsenic and selenium in Drinking Water Samples by Hydride Generation Atomic Fluorescence Spectrometry

    Institute of Scientific and Technical Information of China (English)

    张祥楼

    2014-01-01

    建立了氢化物发生原子荧光光谱法同时测定生活饮用水中砷和硒的方法.测试结果表明砷和硒在质量浓度分别为0.00μg/L~10.00μg/L和0.00μg/L~40.00μg/L范围内呈线性关系,相关系数分别为(砷r=0.9998,硒r=0.9997)。仪器检出限为砷:0.03μg/L硒:0.05μg/L。本方法检出限砷为0.075μg/L;硒为0.125μg/L。水质样品中砷的回收率为92.6%~96.5%,精密度为0.8%~1.4%;硒的回收率为91.2%~97.4%,精密度为1.0%~1.6%。应用本方法测定生活饮用水中的砷和硒方法简便、快速,结果准确可靠,较好地提高了工作效率。%A method for simulatneous determination of Arsenic and selenium in drinking water samples by hydride generation atomic fluorescence spectrometry.As a matter of fact ,the linear range of Arsenic was 0.00μg/L~10.00μg/L and the related coefficient was 0.9998;While the linear range of Selenium was 0.00μg/L~40.00μg/L and the related coefficient was0.9997. Instrument detection limit was 0.03μg/L(arsenic)and 0.05μg/L(selenium).Detection limits of the method was 0.075μg/L (arsenic)and 0.125μg/L(selenium). The rate of arsenic recovery was 92.6%~96.5%and the precision in the drinking water was in the range of 0.8%~1.4%.while the rate of selenium recovery was 92.6%~96.5%and the precision in the drinking water was in the range of 1.0%~1.6%.The experimental results shows that the method is applicable .

  4. Metal Abundances in a Damped Lyman-alpha System Along Two Lines of Sight at z=0.93

    CERN Document Server

    López, S; Gregg, M D; Wisotzki, L; Wucknitz, O; Guzman, A

    2005-01-01

    We study metal abundances in the z=0.9313 damped Lya system observed in the two lines-of-sight, A and B, toward the gravitationally-lensed double QSO HE0512-3329. Spatially resolved STIS spectra constrain the neutral-gas column density to be LogN(HI)=20.5 in both Aand B. UVES spectra (spectral resolution FWHM=9.8 km/s) show, in contrast, significant line-of-sight differences in the column densities of MnII and FeII; these are not due to observational systematics. We find that [Mn/H]=-1.44 and [Fe/H]=-1.52 in damped Lya system A, while [Mn/H]=-0.98 and [Fe/H]>-1.32, and possibly as high as [Fe/H] approx. -1 in damped Lya system B. A careful assessment of possible systematic errors leads us to conclude that these transverse differences are significant at a 5 sigma level or greater. Although nucleosynthesis effects may also be at play, we favor differential dust-depletion as the main mechanism producing the observed abundance gradient. The transverse separation is 5 kpc at the redshift of the absorber, which is ...

  5. Development of Elite BPH-Resistant Wide-Spectrum Restorer Lines for Three and Two Line Hybrid Rice

    Directory of Open Access Journals (Sweden)

    Fengfeng Fan

    2017-06-01

    Full Text Available Hybrid rice has contributed significantly to the world food security. Breeding of elite high-yield, strong-resistant broad-spectrum restorer line is an important strategy for hybrid rice in commercial breeding programs. Here, we developed three elite brown planthopper (BPH-resistant wide-spectrum restorer lines by pyramiding big-panicle gene Gn8.1, BPH-resistant genes Bph6 and Bph9, fertility restorer genes Rf3, Rf4, Rf5, and Rf6 through molecular marker assisted selection. Resistance analysis revealed that the newly developed restorer lines showed stronger BPH-resistance than any of the single-gene donor parent Luoyang-6 and Luoyang-9. Moreover, the three new restorer lines had broad spectrum recovery capabilities for Honglian CMS, Wild abortive CMS and two-line GMS sterile lines, and higher grain yields than that of the recurrent parent 9,311 under nature field conditions. Importantly, the hybrid crosses also showed good performance for grain yield and BPH-resistance. Thus, the development of elite BPH-resistant wide-spectrum restorer lines has a promising future for breeding of broad spectrum BPH-resistant high-yield varieties.

  6. Research on Theories and Techniques of Irrigation for Safeguarding Seed Production of Two-Line Hybrid Rice

    Institute of Scientific and Technical Information of China (English)

    ZOU Jiang-shi; L(U) Chuan-gen; YAO Ke-min; HU Ning; XIA Shi-jian

    2006-01-01

    By inducing frequency, intensity and duration of lower temperature in the middle and last ten-day periods in August in the rice-growing areas of southern China, increasing temperature for safe seed production was defined as 2℃. During the sensitive period of fertility, characters of panicle height and canopy structure of TGMS rice, Pei'ai64S, were measured.Results showed that temperature changes caused by irrigation in fields were below 40 cm of rice plant, and heating effect was significant at 20 cm when the temperature was increased by 3.1℃. For the present study, the following irrigation techniques were put forth: the water depth of 15-20 cm, current water used, irrigating after 17:00 and bailing at 10:00 in sunny or cloudy weather, irrigating on whole day, in shady or rainy weather, increasing inflows and outflows in large fields. In the present experiment, pollen fertility and self-fertilized seed setting rate accepted that the techniques were feasible and effective for against lower temperature and safeguarding seed production of two-line hybrid rice.

  7. Development of Elite BPH-Resistant Wide-Spectrum Restorer Lines for Three and Two Line Hybrid Rice.

    Science.gov (United States)

    Fan, Fengfeng; Li, Nengwu; Chen, Yunping; Liu, Xingdan; Sun, Heng; Wang, Jie; He, Guangcun; Zhu, Yingguo; Li, Shaoqing

    2017-01-01

    Hybrid rice has contributed significantly to the world food security. Breeding of elite high-yield, strong-resistant broad-spectrum restorer line is an important strategy for hybrid rice in commercial breeding programs. Here, we developed three elite brown planthopper (BPH)-resistant wide-spectrum restorer lines by pyramiding big-panicle gene Gn8.1, BPH-resistant genes Bph6 and Bph9, fertility restorer genes Rf3, Rf4, Rf5, and Rf6 through molecular marker assisted selection. Resistance analysis revealed that the newly developed restorer lines showed stronger BPH-resistance than any of the single-gene donor parent Luoyang-6 and Luoyang-9. Moreover, the three new restorer lines had broad spectrum recovery capabilities for Honglian CMS, Wild abortive CMS and two-line GMS sterile lines, and higher grain yields than that of the recurrent parent 9,311 under nature field conditions. Importantly, the hybrid crosses also showed good performance for grain yield and BPH-resistance. Thus, the development of elite BPH-resistant wide-spectrum restorer lines has a promising future for breeding of broad spectrum BPH-resistant high-yield varieties.

  8. Delayed hypersensitivity and migration inhibition in two lines of mice genetically selected for high or low responsiveness to phytohemagglutinin.

    Science.gov (United States)

    Gauthier-Rahman, S; El Rouby, S; Liacopoulos-Briot, M; Stiffel, C; Decreusefond, C; Liacopoulos, P

    1983-04-15

    Delayed-type hypersensitivity (DTH) and cell migration inhibition (MI) were studied in two lines of mice genetically selected for the high (Hi/PHA) or low (Lo/PHA) in vitro response of their lymphoid cells to phytochemagglutinin (PHA). A rapid photoelectric procedure for reading cell migrations enabled the study of MI over a wide range (10 log) of antigen concentrations in vitro. Hi/PHA mice required immunization with a 10 times higher dose of ovalbumin (OVA) in Freund's complete adjuvant (FCA) than Lo/PHA mice for a comparable response in DTH (footpad swelling) and MI of their induced peritoneal exudate cells (PEC). Lo/PHA spleen showed marked bizonal MI on Day 5 after immunization with low doses (0.1 and 0.5 micrograms) of OVA in FCA, one peak being obtained in presence of in vitro concentrations of 10(-3) or 10(-2) micrograms/ml OVA and another peak at 1 or 10 micrograms/ml, whereas Hi/PHA spleen showed stimulation of migration. In contrast, MI in Lo/PHA spleen failed to persist beyond Day 19, whereas it appeared progressively in Hi/PHA spleen, being maximal by Day 27. Low-zone inhibition in Hi/PHA spleen and PEC was lacking or poor even after immunization with higher doses of OVA in FCA. The implications of these findings are discussed.

  9. Fluorescence Microscopy of Nanoscale Silver Oxide Thin Films

    Institute of Scientific and Technical Information of China (English)

    PAN Xin-Yu; JIANG Hong-Bing; LIU Chun-Ling; GONG Qi-Huang; ZHANG Xi-Yao; ZHANG Qi-Feng; XU Bei-Xue; WU Jin-Lei

    2003-01-01

    The experimental conditions for photoactivated intermittent fluorescence from nanoscale silver oxide were studied with fluorescence microscopy. Strong fluorescence was observed from the Ag?O particles with size of 10-20nm excited with both blue and green light. We observed the saturation of photoexcitation with blue light and explained the experimental results using the model of agglomeration of silver atoms to form small clusters and the fluorescence of Ag2 and Ags clusters.

  10. Simple integrated single-atom detector.

    Science.gov (United States)

    Wilzbach, Marco; Heine, Dennis; Groth, Sönke; Liu, Xiyuan; Raub, Thomas; Hessmo, Björn; Schmiedmayer, Jörg

    2009-02-01

    We present a reliable and robust integrated fluorescence detector capable of detecting single atoms. The detector consists of a tapered lensed single-mode fiber for precise delivery of excitation light and a multimode fiber to collect the fluorescence. Both are mounted in lithographically defined SU-8 holding structures on an atom chip. 87Rb atoms propagating freely in a magnetic guide are detected with an efficiency of up to 66%, and a signal-to-noise ratio in excess of 100 is obtained for short integration times.

  11. Interactive effects of temperature and glyphosate on the behavior of blue ridge two-lined salamanders (Eurycea wilderae).

    Science.gov (United States)

    Gandhi, Jaina S; Cecala, Kristen K

    2016-09-01

    The objective of the present study was to evaluate the potential interactive effects of stream temperatures and environmentally relevant glyphosate-based herbicide concentrations on movement and antipredator behaviors of larval Eurycea wilderae (Blue Ridge two-lined salamander). Larval salamanders were exposed to 1 of 4 environmentally relevant glyphosate concentrations (0.00 µg acid equivalent [a.e.]/L, 0.73 µg a.e./L, 1.46 µg a.e./L, and 2.92 µg a.e./L) at either ambient (12 °C) or elevated (23 °C) water temperature. Behaviors observed included the exploration of a novel habitat, use of refuge, habitat selection relative to a potential predator, and burst movement distance. In the absence of glyphosate, temperature consistently affected movement and refuge-use behavior, with individuals moving longer distances more frequently and using refuge less at warm temperatures; however, when glyphosate was added, the authors observed inconsistent effects of temperature that may have resulted from differential toxicity at various temperatures. Larval salamanders made shorter, more frequent movements and demonstrated reduced burst distance at higher glyphosate concentrations. The authors also found that lower glyphosate concentrations sometimes had stronger effects than higher concentrations (i.e., nonmonotonic dose responses), suggesting that standard safety tests conducted only at higher glyphosate concentrations might overlook important sublethal effects on salamander behavior. These data demonstrate that sublethal effects of glyphosate-based herbicides on natural behaviors of amphibians can occur with short-term exposure to environmentally relevant concentrations. Environ Toxicol Chem 2016;35:2297-2303. © 2016 SETAC.

  12. Molecular-sized fluorescent nanodiamonds

    Science.gov (United States)

    Vlasov, Igor I.; Shiryaev, Andrey A.; Rendler, Torsten; Steinert, Steffen; Lee, Sang-Yun; Antonov, Denis; Vörös, Márton; Jelezko, Fedor; Fisenko, Anatolii V.; Semjonova, Lubov F.; Biskupek, Johannes; Kaiser, Ute; Lebedev, Oleg I.; Sildos, Ilmo; Hemmer, Philip. R.; Konov, Vitaly I.; Gali, Adam; Wrachtrup, Jörg

    2014-01-01

    Doping of carbon nanoparticles with impurity atoms is central to their application. However, doping has proven elusive for very small carbon nanoparticles because of their limited availability and a lack of fundamental understanding of impurity stability in such nanostructures. Here, we show that isolated diamond nanoparticles as small as 1.6 nm, comprising only ~400 carbon atoms, are capable of housing stable photoluminescent colour centres, namely the silicon vacancy (SiV). Surprisingly, fluorescence from SiVs is stable over time, and few or only single colour centres are found per nanocrystal. We also observe size-dependent SiV emission supported by quantum-chemical simulation of SiV energy levels in small nanodiamonds. Our work opens the way to investigating the physics and chemistry of molecular-sized cubic carbon clusters and promises the application of ultrasmall non-perturbative fluorescent nanoparticles as markers in microscopy and sensing.

  13. Study on determination of lead in aluminium polychlorid by continuous flow-hydride generation atomic fluorescence spectrometry%连续流动-氢化物发生原子荧光光谱法测定聚合氯化铝中铅

    Institute of Scientific and Technical Information of China (English)

    龚胜芳; 高树林; 李志华; 王红柳

    2014-01-01

    采用连续流动-氢化物发生原子荧光光谱法(CF-HGAFS)测定聚合氯化铝中的铅,优化了实验条件,在最佳实验条件下,铅的荧光强度在0~25μg /L范围内与浓度呈良好的线性关系,方法检出限为0.043μg/L ,方法回收率在95.3%~105.6%之间,本法操作简便、快捷,而且具有很好的准确性和精密度,应用前景良好。%A method for the determination of lead in aluminium polychlorid by continuous flow-hydride generation atomic fluorescence spectrometry was established .The effect of experimental conditions on the atomic fluorescence intensity were investigated and optimized .In this condition ,the calibration curve was linear up to 25μg/L ,the detection limit was 0 .043μg/L ,and the recovery was in range of 95 .3%-105.6% . The method is not only simple and rapid but also precise and accurate ,and shows good application pros-pects .

  14. Atomic physics

    CERN Document Server

    Born, Max

    1989-01-01

    The Nobel Laureate's brilliant exposition of the kinetic theory of gases, elementary particles, the nuclear atom, wave-corpuscles, atomic structure and spectral lines, electron spin and Pauli's principle, quantum statistics, molecular structure and nuclear physics. Over 40 appendices, a bibliography, numerous figures and graphs.

  15. Atomic Calligraphy

    Science.gov (United States)

    Imboden, Matthias; Pardo, Flavio; Bolle, Cristian; Han, Han; Tareen, Ammar; Chang, Jackson; Christopher, Jason; Corman, Benjamin; Bishop, David

    2013-03-01

    Here we present a MEMS based method to fabricate devices with a small number of atoms. In standard semiconductor fabrication, a large amount of material is deposited, after which etching removes what is not wanted. This technique breaks down for structures that approach the single atom limit, as it is inconceivable to etch away all but one atom. What is needed is a bottom up method with single or near single atom precision. We demonstrate a MEMS device that enables nanometer position controlled deposition of gold atoms. A digitally driven plate is swept as a flux of gold atoms passes through an aperture. Appling voltages on four comb capacitors connected to the central plate by tethers enable nanometer lateral precision in the xy plane over 15x15 sq. microns. Typical MEMS structures have manufacturing resolutions on the order of a micron. Using a FIB it is possible to mill apertures as small as 10 nm in diameter. Assuming a low incident atomic flux, as well as an integrated MEMS based shutter with microsecond response time, it becomes possible to deposit single atoms. Due to their small size and low power consumption, such nano-printers can be mounted directly in a cryogenic system at ultrahigh vacuum to deposit clean quench condensed metallic structures.

  16. Coherent backscattering of light off one-dimensional atomic strings

    CERN Document Server

    Sørensen, H L; Kluge, K W; Iakoupov, I; Sørensen, A S; Müller, J H; Polzik, E S; Appel, J

    2016-01-01

    Bragg scattering, well known in crystallography, has become a powerful tool for artificial atomic structures such as optical lattices. In an independent development photonic waveguides have been used successfully to boost quantum light-matter coupling. We combine these two lines of research and present the first experimental realisation of coherent Bragg scattering off a one-dimensional (1D) system - two strings of atoms strongly coupled to a single photonic mode - realised by trapping atoms in the evanescent field of a tapered optical fibre (TOF), which also guides the probe light. We report nearly 12% power reflection from strings containing only about one thousand caesium atoms, an enhancement of more than two orders of magnitude compared to reflection from randomly positioned atoms. This result paves the road towards collective strong coupling in 1D atom-photon systems. Our approach also allows for a straightforward fibre connection between several distant 1D atomic crystals.

  17. Kinetic Atom.

    Science.gov (United States)

    Wilson, David B.

    1981-01-01

    Surveys the research of scientists like Joule, Kelvin, Maxwell, Clausius, and Boltzmann as it comments on the basic conceptual issues involved in the development of a more precise kinetic theory and the idea of a kinetic atom. (Author/SK)

  18. The spectroscopy in the atomic vapour

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jai Hyung; Chang, Joon Sung; Jhe, Won Ho [Seoul National University, Seoul (Korea)

    1998-04-01

    As spectroscopies in the atomic vapor, we perform experiments on fluorescence in dense atomic vapor, single color two-photon resonant three photon ionization, production of high temperature oven and its spectroscopic application, atomic trap and cold atomic beam. We observe lengthening of lifetime as atomic density increase and compare this result with Holstein equation. Dependence on pressure an d polarization reveals the result is due to collisions between Yb atom and Ar buffer gas. At high atomic density, self-focusing and conical emission are observed. In two-photon resonant three photon ionization scheme, ionization rate is dependent on polarization. From selection rule, we determined the energy level. At higher energy, asymmetry and broadening of ionization linewidth due to AC Stark effect are observed. As the result of numerical simulation of time evolution in the two-photon transition, distortion of time evolution of density is obtained. For spectroscopy of high-melting-point elements, we design and produce high temperature oven. We observe absorption spectra of high-melting-point elements, Er and Sm. As high temperature nonlinear spectroscopies, we perform conical emission and self-diffraction in Sm vapor. We produce magneto-optical trap system and measure fluorescence from trapped atoms and temperature. By trapping Rb isotopes simultaneously, we perform collision experiment at low temperature. Using hollow mirror system, we trap atoms and produce cold atomic beam. (author). 160 refs., 66 figs., 5 tabs.

  19. Fluorescence-Based Sensors

    Science.gov (United States)

    Orellana, Guillermo

    The natural luminescent phenomena (from the Latin words "lumen" and "essentia", i.e., "made of light") such as northern lights (aurora borealis), marine brightness, glow-worms, shining putrid fish scales, "bluish"- appearing water when contained in certain wooden cups (quinine fluorescence), some stones heated at high temperatures with reducing agents (BaS phosphorescence), or light emitted while crushing sugar (triboluminescence) already fascinated our ancestors. Nowadays we understand that ultraviolet and visible emission of light originates from a competitive deactivation pathway of the lowest electronic excited state of atoms and molecules that produces the so called luminescence (the sub-terms fluorescence and phosphorescence just designate whether the return of the excited to the ground state is an "allowed" or "forbidden" process, namely it is fast or slow, the loosely-defined border between them being a 1-μs-1 rate constant). Actually, luminescence is the only method to generate light in the known Universe regardless it is powered by the nuclear reactions in the stars, the ohmical heating in bulbs, an electric discharge, the absorption of light or a (bio)chemical reaction (chemiluminescence).

  20. Peptide-stabilized, fluorescent silver nanoclusters

    DEFF Research Database (Denmark)

    Gregersen, Simon; Vosch, Tom André Jos; Jensen, Knud Jørgen

    2016-01-01

    . Herein, we demonstrate how solid-phase methods can increase throughput dramatically in peptide ligand screening and in initial evaluation of fluorescence intensity and chemical stability of peptide-stabilized AgNCs (P-AgNCs). 9-Fluorenylmethyloxycarbonyl (Fmoc) solid-phase peptide synthesis......Few-atom silver nanoclusters (AgNCs) can exhibit strong fluorescence; however, they require ligands to prevent aggregation into larger nanoparticles. Fluorescent AgNCs in biopolymer scaffolds have so far mainly been synthesized in solution, and peptides have only found limited use compared to DNA...

  1. 高效液相色谱氢化物发生原子荧光光谱联用检测海藻中砷形态%Determination of arsenic speciation in seaweeds using high performance liquid chromatography-ultraviolet photo-oxidation-hydride generation-atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    高鹭; 董伟峰; 彭心婷; 史立娟; 李妍; 庞艳华; 徐静; 曹际娟

    2015-01-01

    目的:测定14种海藻样品中总砷和无机砷的含量,同时分析样品中6种砷形态。方法将海藻样品经过微波消解的前处理方法,通过电感耦合等离子体质谱(inductively coupled plasma mass spectrometry, ICP-MS)测定总砷含量;根据国标方法中无机砷检测的前处理方法,通过原子荧光光谱(atomic fluorescence spectrometry, AFS)测定无机砷含量;最后通过酸提的前处理方法,利用高效液相色谱-氢化物发生-原子荧光光谱法(high performance liquid chromatography-ultraviolet photo-oxidation-hydride generation-atomic fluorescence spectrometry, HPLC-(UV)-HG-AFS)测定海藻样品中6种形态砷含量并与国标无机砷方法比较。结果14种海藻样品中总砷含量为0.038~46.2 mg/kg;无机砷含量为0.006~19.3 mg/kg;对HPLC-(UV)-HG-AFS仪器的优化和方法的摸索后,从海藻样品中主要测得的砷形态为As(III)、As(V)和DMA, MMA含量较少,没有测出AsB和 AsC。结论在砷形态较为复杂的海藻样品检测中,通过 HPLC-(UV)-HG-AFS 检测方法可以有效避免无机砷前处理中可能出现的有机砷向无机砷转变的现象,降低干扰,增加测试的准确性,更为具体地表现海藻样品中主要的砷形态含量。%Objective The content of total arsenic and inorganic arsenic were determined in 14 seaweeds and 6 kinds of arsenic species were determined at the same time. Methods The content of total arsenic was determined by inductively coupled plasma mass spectrometry (ICP-MS) after microwave digestion. According to the pretreatment method of national standard method, the content of inorganic arsenic was determined by atomic fluorescence spectrometry (AFS). The results of 6 arsenic species were studied by high performance liquid chromatography-ultraviolet photo-oxidation-hydride generation-atomic fluorescence spectrometry (HPLC-(UV)-HG-AFS) after acid extraction, which were compared with the national standard method. Results In 14

  2. Atomic theories

    CERN Document Server

    Loring, FH

    2014-01-01

    Summarising the most novel facts and theories which were coming into prominence at the time, particularly those which had not yet been incorporated into standard textbooks, this important work was first published in 1921. The subjects treated cover a wide range of research that was being conducted into the atom, and include Quantum Theory, the Bohr Theory, the Sommerfield extension of Bohr's work, the Octet Theory and Isotopes, as well as Ionisation Potentials and Solar Phenomena. Because much of the material of Atomic Theories lies on the boundary between experimentally verified fact and spec

  3. Mercury speciation by high-performance liquid chromatography atomic fluorescence spectrometry using an integrated microwave/UV interface. Optimization of a single step procedure for the simultaneous photo-oxidation of mercury species and photo-generation of Hg{sup 0}

    Energy Technology Data Exchange (ETDEWEB)

    Quadros, Daiane P.C. de [Departamento de Química, Universidade Federal de Santa Catarina, 88040-970 Florianópolis, SC (Brazil); Campanella, Beatrice; Onor, Massimo; Bramanti, Emilia [National Research Council of Italy, C.N.R., Instituto di Chimica dei Composti Organo Metallici – ICCOM – UOS Pisa, Area della Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Borges, Daniel L.G. [Departamento de Química, Universidade Federal de Santa Catarina, 88040-970 Florianópolis, SC (Brazil); D' Ulivo, Alessandro, E-mail: dulivo@pi.iccom.cnr.it [National Research Council of Italy, C.N.R., Instituto di Chimica dei Composti Organo Metallici – ICCOM – UOS Pisa, Area della Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy)

    2014-11-01

    We described the hyphenation of photo-induced chemical vapor generation with high performance liquid chromatography–atomic fluorescence spectrometry (HPLC–AFS) for the quantification of inorganic mercury, methylmercury (MeHg) and ethylmercury (EtHg). In the developed procedure, formic acid in mobile phase was used for the photodecomposition of organomercury compounds and reduction of Hg{sup 2+} to mercury vapor under microwave/ultraviolet (MW/UV) irradiation. We optimized the proposed method studying the influence of several operating parameters, including the type of organic acid and its concentration, MW power, composition of HPLC mobile phase and catalytic action of TiO{sub 2} nanoparticles. Under the optimized conditions, the limits of detection were 0.15, 0.15 and 0.35 μg L{sup −1} for inorganic mercury, MeHg and EtHg, respectively. The developed method was validated by determination of the main analytical figures of merit and applied to the analysis of three certified reference materials. The online interfacing of liquid chromatography with photochemical-vapor generation–atomic fluorescence for mercury determination is simple, environmentally friendly, and represents an attractive alternative to the conventional tetrahydroborate (THB) system. - Highlights: • Inorganic and organic mercury were determined by photochemical vapor generation using a MW/UV photochemical reactor. • The optimized procedure has been applied to the speciation of Hg(II), MeHg and EtHg coupling HPLC with PVG–AFS. • The proposed method is simple, sensitive, and is established for mercury determination in biological materials.

  4. Resonator-Aided Single-Atom Detection on a Microfabricated Chip

    OpenAIRE

    Teper, Igor; Lin, Yu-Ju; Vuletic, Vladan

    2006-01-01

    We use an optical cavity to detect single atoms magnetically trapped on an atom chip. We implement the detection using both fluorescence into the cavity and reduction in cavity transmission due to the presence of atoms. In fluorescence, we register 2.0(2) photon counts per atom, which allows us to detect single atoms with 75% efficiency in 250 microseconds. In absorption, we measure transmission attenuation of 3.3(3)% per atom, which allows us to count small numbers of atoms with a resolution...

  5. High-Definition X-Ray Fluorescence: Applications

    OpenAIRE

    Gibson, Walter M.; Chen, Z W; Li, Danhong

    2008-01-01

    Energy dispersive X-ray fluorescence (EDXRF) is a well-established and powerful tool for nondestructive elemental analysis of virtually any material. It is widely used for environmental, industrial, pharmaceutical, forensic, and scientific research applications to measure the concentration of elemental constituents or contaminants. The fluorescing atoms can be excited by energetic electrons, ions, or photons. A particular EDXRF method, monochromatic microbeam X-ray fluorescence (MμEDXRF), has...

  6. High Definition X-Ray Fluorescence: Principles and Techniques

    OpenAIRE

    Chen, Z W; Gibson, Walter M.; Huang, Huapeng

    2008-01-01

    Energy dispersive X-ray fluorescence (EDXRF) is a well-established and powerful tool for nondestructive elemental analysis of virtually any material. It is widely used for environmental, industrial, pharmaceutical, forensic, and scientific research applications to measure the concentration of elemental constituents or contaminants. The fluorescing atoms can be excited by energetic electrons, ions, or photons. A particular EDXRF method, monochromatic microfocus X-ray fluorescence (MμEDXRF), ha...

  7. Two-photon ionization of colliding atoms

    Energy Technology Data Exchange (ETDEWEB)

    Nayfeh, M.H.

    1977-09-01

    Semiclassical expressions of two-photon ionization of two colliding atoms are derived for a wide range of electromagnetic field intensity and detunings from the isolated atom line. The dependence of the ionization yield on the details of the interaction potential of the system is derived. This process promises an extremely sensitive method for studying line broadening on the far wing, especially when absorption or fluorescence becomes very weak.

  8. Atomic rivals

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmidt, B.

    1990-01-01

    This book is a memoir of rivalries among the Allies over the bomb, by a participant and observer. Nuclear proliferation began in the uneasy wartime collaboration of the United States, England, Canada, and Free France to produce the atom bomb. Through the changes of history, a young French chemist had a role in almost every act of this international drama. This memoir is based on Goldschmidt's own recollections, interviews with other leading figures, and 3,000 pages of newly declassified documents in Allied archives. From his own start as Marie Curie's lab assistant, Goldschmidt's career was closely intertwined with Frances complicated rise to membership in the nuclear club. As a refugee from the Nazis, he became part of the wartime nuclear energy project in Canada and found himself the only French scientist to work (although briefly) on the American atom bomb project.

  9. Fluorescence analysis of iodinated acetophenone derivatives.

    Science.gov (United States)

    Crivelaro, F; Oliveira, M R S; Lima, S M; Andrade, L H C; Casagrande, G A; Raminelli, C; Caires, A R L

    2015-03-15

    In the present paper the synthesis and optical characterization of iodinated acetophenone, 4-hydroxy-3-iodoacetophenone and 4-hydroxy-3,5-diiodoacetophenone obtained from 4-hydroxyacetophenone, were carried out. The optical features of iodinated molecules were determined by performing the UV-Vis absorption, fluorescence and thermal lens spectroscopies. The results showed that the optical properties of the 4-hydroxyacetophenone is altered when the iodine atom is inserted, as substituent, in the aromatic ring. Although it was determined that the optical feature was changed when one iodine atom was inserted in the aromatic ring (4-hydroxy-3-iodoacetophenone), the results revealed that emission behavior was strongly altered when two iodine atoms (4-hydroxy-3,5-diiodoacetophenone) were acting as substituents: the fluorescence quantum efficiency increases approximately 60%.

  10. Highly Fluorescent Noble Metal Quantum Dots

    Science.gov (United States)

    Zheng, Jie; Nicovich, Philip R.; Dickson, Robert M.

    2009-01-01

    Highly fluorescent, water-soluble, few-atom noble metal quantum dots have been created that behave as multi-electron artificial atoms with discrete, size-tunable electronic transitions throughout the visible and near IR. These “molecular metals” exhibit highly polarizable transitions and scale in size according to the simple relation, Efermi/N1/3, predicted by the free electron model of metallic behavior. This simple scaling indicates that fluorescence arises from intraband transitions of free electrons and that these conduction electron transitions are the low number limit of the plasmon – the collective dipole oscillations occurring when a continuous density of states is reached. Providing the “missing link” between atomic and nanoparticle behavior in noble metals, these emissive, water-soluble Au nanoclusters open new opportunities for biological labels, energy transfer pairs, and light emitting sources in nanoscale optoelectronics. PMID:17105412

  11. Single molecule DNA detection with an atomic vapor notch filter

    National Research Council Canada - National Science Library

    Uhland, Denis; Rendler, Torsten; Widmann, Matthias; Lee, Sang-Yun; Wrachtrup, Jörg; Gerhardt, Ilja

    2015-01-01

    .... Here we present the use of the narrow-band filtering properties of hot atomic sodium vapor to selectively filter the excitation light from the red-shifted fluorescence of dye labeled single-stranded DNA molecules...

  12. Atomic physics

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, A.E.; Kukla, K.; Cheng, S. [Univ. of Toledo, OH (United States)] [and others

    1995-08-01

    In a collaboration with the Atomic Physics group at Argonne and the University of Toledo, the Atomic Physics group at the University of Notre Dame is measuring the fine structure transition energies in highly-charged lithium-like and helium-like ions using beam-foil spectroscopy. Precise measurements of 2s-2p transition energies in simple (few-electron) atomic systems provide stringent tests of several classes of current atomic- structure calculations. Analyses of measurements in helium-like Ar{sup 16+} have been completed, and the results submitted for publication. A current goal is to measure the 1s2s{sup 3}S{sub 1} - 1s2p{sup 3}P{sub 0} transition wavelength in helium-like Ni{sup 26+}. Measurements of the 1s2s{sup 2}S{sub 1/2} - 1s2p{sup 2}P{sub 1/2,3/2} transition wavelengths in lithium-like Kr{sup 33+} is planned. Wavelength and lifetime measurements in copper-like U{sup 63+} are also expected to be initiated. The group is also participating in measurements of forbidden transitions in helium-like ions. A measurement of the lifetime of the 1s2s{sup 3}S{sub 1} state in Kr{sup 34+} was published recently. In a collaboration including P. Mokler of GSI, Darmstadt, measurements have been made of the spectral distribution of the 2E1 decay continuum in helium-like Kr{sup 34+}. Initial results have been reported and further measurements are planned.

  13. The Atomic orbitals of the topological atom

    OpenAIRE

    Ramos-Cordoba, Eloy; Salvador Sedano, Pedro

    2013-01-01

    The effective atomic orbitals have been realized in the framework of Bader's atoms in molecules theory for a general wavefunction. This formalism can be used to retrieve from any type of calculation a proper set of orthonormalized numerical atomic orbitals, with occupation numbers that sum up to the respective Quantum Theory of Atoms in Molecules (QTAIM) atomic populations. Experience shows that only a limited number of effective atomic orbitals exhibit significant occupation numbers. These c...

  14. Fundamentals of fluorescence and fluorescence microscopy.

    Science.gov (United States)

    Wolf, David E

    2013-01-01

    This chapter discusses the fundamental physics of fluorescence. The application of fluorescence to microscopy represents an important transition in the development of microscopy, particularly as it applies to biology. It enables quantitating the amounts of specific molecules within a cell, determining whether molecules are complexing on a molecular level, measuring changes in ionic concentrations within cells and organelles, and measuring molecular dynamics. This chapter also discusses the issues important to quantitative measurement of fluorescence and focuses on four of quantitative measurements of fluorescence--boxcar-gated detection, streak cameras, photon correlation, and phase modulation. Although quantitative measurement presents many pitfalls to the beginner, it also presents significant opportunities to one skilled in the art. This chapter also examines how fluorescence is measured in the steady state and time domain and how fluorescence is applied in the modern epifluorescence microscope.

  15. Laser-saturated fluorescence measurements in laminar sooting diffusion flames

    Science.gov (United States)

    Wey, Changlie

    1993-01-01

    The hydroxyl radical is known to be one of the most important intermediate species in the combustion processes. The hydroxyl radical has also been considered a dominant oxidizer of soot particles in flames. In this investigation the hydroxyl concentration profiles in sooting diffusion flames were measured by the laser-saturated fluorescence (LSF) method. The temperature distributions in the flames were measured by the two-line LSF technique and by thermocouple. In the sooting region the OH fluorescence was too weak to make accurate temperature measurements. The hydroxyl fluorescence profiles for all four flames presented herein show that the OH fluorescence intensities peaked near the flame front. The OH fluorescence intensity dropped sharply toward the dark region of the flame and continued declining to the sooting region. The OH fluorescence profiles also indicate that the OH fluorescence decreased with increasing height in the flames for all flames investigated. Varying the oxidizer composition resulted in a corresponding variation in the maximum OH concentration and the flame temperature. Furthermore, it appears that the maximum OH concentration for each flame increased with increasing flame temperature.

  16. Atom Skimmers and Atom Lasers Utilizing Them

    Science.gov (United States)

    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.

  17. Reviews in fluorescence 2010

    CERN Document Server

    Geddes, Chris D

    2011-01-01

    ""Reviews in Fluorescence 2010"", the seventh volume of the book serial from Springer, serves as a comprehensive collection of current trends and emerging hot topics in the field of fluorescence and closely related disciplines. It summarizes the year's progress in fluorescence and its applications, with authoritative analytical reviews specialized enough to be attractive to professional researchers, yet also appealing to the wider audience of scientists in related disciplines of fluorescence. ""Reviews in Fluorescence"" offers an essential reference material for any lab working in the fluoresc

  18. Principles of fluorescence techniques

    CERN Document Server

    2016-01-01

    Fluorescence techniques are being used and applied increasingly in academics and industry. The Principles of Fluorescence Techniques course will outline the basic concepts of fluorescence techniques and the successful utilization of the currently available commercial instrumentation. The course is designed for students who utilize fluorescence techniques and instrumentation and for researchers and industrial scientists who wish to deepen their knowledge of fluorescence applications. Key scientists in the field will deliver theoretical lectures. The lectures will be complemented by the direct utilization of steady-state and lifetime fluorescence instrumentation and confocal microscopy for FLIM and FRET applications provided by leading companies.

  19. Building a Single Atom Microscope for Nuclear Astrophysics

    Science.gov (United States)

    Frisbie, Dustin; Johnson, Maegan; Parzuchowski, Kristen; Wenzl, Jennifer; Singh, Jaideep

    2017-01-01

    The primary research goal of this project is to develop a new technique of optical single atom detection to measure rare nuclear reactions at low energies. The 22Ne(α, n)25Mg reaction is of particular interest, as it is thought to be a primary source of neutrons in the s-process of massive stars. Nuclear reaction products are captured in a cryogenically frozen film of noble gas, which can contain a variety of guest atoms. These solids are ideal to use because they are optically transparent and simple to grow and purify. The sample is illuminated by laser light and imaged to identify fluorescing atoms. The atomic transitions of captured atoms indicate which atoms are present; only atoms which are excited at the laser wavelength will fluoresce. This offers high selectivity during experiments. We began development with Yb, a very bright guest atom, being embedded in a host of solid neon in order to study the optical properties necessary for single atom detection. In addition, we study background effects from the laser exciting contaminants in our substrates. We present data that indicates the efficiency with which we can excite and collect fluorescence light with our apparatus, and use it to propose a strategy for the development of Mg single atom detection. This work is generously supported by Michigan State University.

  20. 氢化物原子荧光光谱法同时测定血液透析用水中的砷和锑%Simultaneous determination of arsenic and antimony in blood dialysis water by hydride atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    汪洋; 邵丽华; 魏滨; 何漪

    2011-01-01

    Objective:To establish a method for the simultaneous determination of arsenic and antimony in blood dialysis water by hydride atomic fluorescence spectrometry. Methods: The working condition of the determination were studied and optimized for the simultaneous determination of arsenic and antimony in blood dialysis water by hydride atomic fluorescence spectrometry.Results: The detection limits of this method were found to be 0.40 μg/L for arsenic and 0.50 μg/L for antimony, and the RSD were in the range of 2.2% ~ 4.2% for arsenic and 3.2% ~ 5.3% for antimony. The recovery tates of standard spiking for arsenic and antimony were in the range of 94.0% ~ 101.2% and 98.9% ~ 103.6%, respectively. Conclusion: The method is sensitive, accurate and rapid. It can be adopted for simultaneous determination of arsenic and antimony in blood dialysis water.%目的:建立一种氢化物原子荧光光谱法同时测定血液透析用水中的砷和锑的方法.方法:优化测定条件,采用氢化物原子荧光光谱法同时测定血液透析用水中的砷和锑.结果:砷和锑的检出限、相对标准偏差、回收率分别为:0.40μg/L和0.50 μg/L;2.2%~4.2%和3.2%~5.3%;94.0%~101.2%和98.9%~103.6%.结论:本方法灵敏度高,准确、快捷,能同时测定血液透析用水中的砷和锑,省时、省力.

  1. Experimental Investigation of Excited-State Lifetimes in Atomic Ytterbium

    Energy Technology Data Exchange (ETDEWEB)

    Bowers, C.J.; Budker, D.; Commins, E.D.; DeMille, D.; Freedman, S.J.; Nguyen, A.-T.; Shang, S.-Q.; /UC, Berkeley; Zolotorev, M.; /SLAC

    2011-11-15

    Lifetimes of 21 excited states in atomic Yb were measured using time-resolved fluorescence detection following pulsed laser excitation. The lifetime of the 4f{sup 14}5d6s {sup 3}D{sub 1} state, which is of particular importance for a proposed study of parity nonconservation in atoms, was measured to be 380(30) ns.

  2. Electrochemical hydride generation atomic fluorescence spectrometry with a polyanline modified electrode for detection of tin%聚苯胺修饰电极-电化学氢化物发生原子荧光光谱法测定食品中锡含量

    Institute of Scientific and Technical Information of China (English)

    姜宪娟; 淦五二

    2012-01-01

    An electrochemical hydride generation (EC-HG) system with a polyaniline modified electrode (Pan-ME) as cathode material was developed for Sn ( Ⅳ) determination by couped with atomic fluorescence spectrometry. The electrochemical hydride generation efficiency for Sn (Ⅳ) was improved evidently as the Pan membrane could obstruct the aggradation of Sn atom on cathode surface and facilitate the hydride generation. The effects of experimental parameters and interferences have been studied. The limit of detection ( LOD) was 1. 2 ng/mL (3σ) and the relative standard deviation (RSD) was 2. 3% for eleven consecutive measurements of 50 ng/mL Sn(IV) standard solution.%运用以聚苯胺修饰的石墨电极为阴极的电化学氢化物发生装置实现了锡元素的电化学氢化物发生.在电极表面聚合一层聚苯胺,能够有效地提高锡元素的电化学氢化物发生效率,通过与原子荧光光谱仪联用,成功地测定了食品中的锡含量.本工作对各种实验参数和干扰情况进行了详细研究.方法对锡的检出限为1.2 ng/mL(3σ);样品分析精密度(RSD)为2.3% (50 ng/mL,n=11).

  3. Atomic magnetometer

    Science.gov (United States)

    Schwindt, Peter [Albuquerque, NM; Johnson, Cort N [Albuquerque, NM

    2012-07-03

    An atomic magnetometer is disclosed which uses a pump light beam at a D1 or D2 transition of an alkali metal vapor to magnetically polarize the vapor in a heated cell, and a probe light beam at a different D2 or D1 transition to sense the magnetic field via a polarization rotation of the probe light beam. The pump and probe light beams are both directed along substantially the same optical path through an optical waveplate and through the heated cell to an optical filter which blocks the pump light beam while transmitting the probe light beam to one or more photodetectors which generate electrical signals to sense the magnetic field. The optical waveplate functions as a quarter waveplate to circularly polarize the pump light beam, and as a half waveplate to maintain the probe light beam linearly polarized.

  4. High Atom Number in Microsized Atom Traps

    Science.gov (United States)

    2015-12-14

    Final Performance Report on ONR Grant N00014-12-1-0608 High atom number in microsized atom traps for the period 15 May 2012 through 14 September...TYPE Final Technical Report 3. DATES COVERED (From - To) 05/15/2012-09/14/2012 4. TITLE AND SUBTITLE High atom number in microsized atom traps...forces for implementing a small-footprint, large-number atom -chip instrument. Bichromatic forces rely on absorption and stimulated emission to produce

  5. 工作场所空气中汞及其化合物的原子荧光光谱测定法%Atomic fluorescence spectrometry determination of mercury and its compounds in workplace air

    Institute of Scientific and Technical Information of China (English)

    刘小娟; 张彩霞; 王晓红

    2012-01-01

    The standard curve, sample processing of GBZ / T 160. 14 - 2004 "toxic substances in workplace air-determination of mercury and its compounds" were improved for the accuracy of measurement. The method standard curve range was 0. 002 - 0. 014μg /mL, the correlation coefficient r = 0. 9994, regression equation If=71424C+5. 7623. High medium and low concentration of the standard precision of 1. 9%, 4. 1% , 4. 9%. The detection limit was 0. 001 spiked recoveries in the range 92% to 98%. The results showed that the processing of samples and standard curve preparation should note that glass pickling and to avoid contamination after acid with potassium borohydride solution soak, and eliminate pollution. Reducing agent is currently using the existing service. The detector can choose to replace contaminated piping and quartz furnace soak with aqua regia (atomizer).%本文在标准曲线、样品处理方面对GBZ/T 160.14-2004《工作场所空气中有毒物质测定 汞及其化合物》进行改进,提高了测量的准确性.标准曲线范围0.002~0.014 μg/mL,相关系数r=0.9994,回归方程If=71424C+5.7623.高、中、低浓度标准的精密度分别为1.9%、4.1%、4.9%.检出限为0.001 μg/mL,加标回收率范围92%~98%.样品的处理及标准益线的配制应注意玻璃器皿的酸洗和避免污染,酸洗后用硼氢化钾溶液浸泡一下,消除污染.还原剂现用现配.检测器被污染可更换管路或用王水浸泡清洗石英炉(原子化器).

  6. Fluorescence correlation spectroscopy

    NARCIS (Netherlands)

    Hink, M.A.; Verveer, P.J.

    2015-01-01

    Fluorescence fluctuation spectroscopy techniques allow the quantification of fluorescent molecules present at the nanomolar concentration level. After a brief introduction to the technique, this chapter presents a protocol including background information in order to measure and quantify the molecul

  7. CANAS '01 - Colloquium analytical atomic spectroscopy; CANAS '01 - Colloquium Analytische Atomspektroskopie. Programm. Kurzfassungen der Vortraege und Poster

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The main topics of the meeting on analytical atom spectroscopy were: optical atom spectrometry, x-ray fluorescence analysis, absorption spectroscopy, icp mass spectroscopy, trace analysis, sampling, sample preparation and quality assurance.

  8. Safe biodegradable fluorescent particles

    Science.gov (United States)

    Martin, Sue I.; Fergenson, David P.; Srivastava, Abneesh; Bogan, Michael J.; Riot, Vincent J.; Frank, Matthias

    2010-08-24

    A human-safe fluorescence particle that can be used for fluorescence detection instruments or act as a safe simulant for mimicking the fluorescence properties of microorganisms. The particle comprises a non-biological carrier and natural fluorophores encapsulated in the non-biological carrier. By doping biodegradable-polymer drug delivery microspheres with natural or synthetic fluorophores, the desired fluorescence can be attained or biological organisms can be simulated without the associated risks and logistical difficulties of live microorganisms.

  9. 氢化物发生-非色散原子荧光光谱法同时测定金精矿中痕量铋和汞%Simultaneous determination of trace bismuth and mercury in gold concentrates by hydride generation-nondispersive atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    马熠罡

    2012-01-01

    The method of simultaneous determination of trace bismuth and mercury in gold concentrates by hydride generation-nondispersive atomic fluorescence spectrometry was proposed. The samples were digested by HNO3/HCI and then some references were marked by potassium thiocyanate and thiourea. Calculated the detection limits are 5.6 mg/L and 0. 7 mg/L. The method detection limits are 0. 13 μg/g and 0.012 μg/g,and the precision were 1.2% and 0.6% ,respectively.%采用HNO3/HCl消解,以硫氰化钾掩蔽金,硫脲掩蔽杂质等手段,建立王水消解-双道氢化物发生原子荧光光谱同时测定金精矿中铋和汞含量的新方法.计算出Bi和Hg的检出限分别为5.6,0.7 mg/L,方法的检出限分别为0.13μg/g和0.012 μg/g,精密度分别为1.2%和0.6%.

  10. "Bohr's Atomic Model."

    Science.gov (United States)

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  11. The atomic orbitals of the topological atom.

    Science.gov (United States)

    Ramos-Cordoba, Eloy; Salvador, Pedro; Mayer, István

    2013-06-07

    The effective atomic orbitals have been realized in the framework of Bader's atoms in molecules theory for a general wavefunction. This formalism can be used to retrieve from any type of calculation a proper set of orthonormalized numerical atomic orbitals, with occupation numbers that sum up to the respective Quantum Theory of Atoms in Molecules (QTAIM) atomic populations. Experience shows that only a limited number of effective atomic orbitals exhibit significant occupation numbers. These correspond to atomic hybrids that closely resemble the core and valence shells of the atom. The occupation numbers of the remaining effective orbitals are almost negligible, except for atoms with hypervalent character. In addition, the molecular orbitals of a calculation can be exactly expressed as a linear combination of this orthonormalized set of numerical atomic orbitals, and the Mulliken population analysis carried out on this basis set exactly reproduces the original QTAIM atomic populations of the atoms. Approximate expansion of the molecular orbitals over a much reduced set of orthogonal atomic basis functions can also be accomplished to a very good accuracy with a singular value decomposition procedure.

  12. Plant Type and Its Effects on Canopy Structure at Heading Stage in Various Ecological Areas for a Two-line Hybrid Rice Combination, Liangyoupeijiu

    Institute of Scientific and Technical Information of China (English)

    LU Chuan-gen; HU Ning; YAO Ke-min; XIA Shi-jian; QI Qing-ming

    2010-01-01

    A two-line hybrid rice combination, Liangyoupeijiu, was used to estimate several factors of plant type, and environmental models for these factors at the heading stage were established using the data of eight ecological experimental sites in 2006 and 2007. According to climatic data from 1951 to 2005, the differences in those factors and their effects on plant canopy were analyzed for four rice cropping areas in China, including South China, the middle-lower reaches of the Yangtze River, Sichuan Basin, and river valley in Yunnan, China. The thickness of leaf layer (the distance from pulvinus of the third leaf from the top to the tip of flag leaf) and distribution of leaf area could be used as candidate indices for the plant type of a rice canopy.

  13. Defect-free atom arrays on demand

    Science.gov (United States)

    Levine, Harry; Bernien, Hannes; Keesling, Alex; Anschuetz, Eric; Senko, Crystal; Vuletic, Vladan; Greiner, Markus; Endres, Manuel; Lukin, Mikhail

    2016-05-01

    Arrays of neutral, trapped atoms have proven to be an extraordinary platform for studying quantum many-body physics and implementing quantum information protocols. Conventional approaches to generate such arrays rely on loading atoms into optical lattices and require elaborate experimental control. An alternative, simpler approach is to load atoms into individual optical tweezers. However, the probabilistic nature of the loading process limits the size of the arrays to small numbers of atoms. Here we present a new method for assembling defect-free arrays of large numbers of atoms. Our technique makes use of an array of tightly focused optical tweezers generated by an acousto-optic deflector. The positions of the traps can be dynamically reconfigured on a sub-millisecond timescale. With single-site resolved fluorescence imaging, we can identify defects in the atom array caused by the probabilistic loading process and rearrange the trap positions in response. This will enable us to generate defect-free atom arrays on demand. We discuss our latest results towards reaching this goal along with schemes to implement long-range interactions between atoms in the array. Now at Caltech.

  14. Metastable states' population of uranium atoms produced by electron-beam heating

    Energy Technology Data Exchange (ETDEWEB)

    Ohba, Hironori; Shibata, Takemasa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nishimura, Akihiko; Ogura, Koichi [Japan Atomic Energy Research Inst., Kansai Research Establishment, Advanced Photon Research Center, Kyoto (Japan)

    2000-08-01

    The metastable states' population densities of uranium atoms produced by electron-beam heating were measured by the laser induced fluorescence method. The atomic excitation temperature derived from the metastable state distribution was lower than the evaporation surface temperature. With increasing deposition rate, the atomic excitation temperature decreased to about 2000 K. (author)

  15. Heavy atom quenched coumarin probes for sensitive and selective detection of biothiols in living cells.

    Science.gov (United States)

    Ji, Wengang; Ji, Yuzhuo; Jin, Qingqing; Tong, Qingxiao; Tang, Xinjing

    2015-07-07

    A series of turn-on fluorescent probes with halogen acetyl amide at the 3-position of coumarin derivatives were synthesized. Fluorescence of these probes was efficiently quenched by heavy halogen atoms (Br and I, not Cl), which could be successfully used for selective detection of biothiols with the sensitivity of Cys > GSH > Hcy and much higher than thiol containing proteins. These represent the smallest fluorescence quenchers in designing fluorescent probes for detecting both endogenous and exogenous biothiols in living cells.

  16. Determination of inorganic arsenic in coal by hydride generation atomic fluorescence spectrometry combined with ultrasonic extraction%超声提取-顺序注射氢化物发生-原子荧光光谱法测定煤中无机砷

    Institute of Scientific and Technical Information of China (English)

    王长芹; 刘贵勤

    2011-01-01

    A determination method of inorganic arsemc in coal was established by sequence injection hydride generation-atomic fluorescence spectrometry ( HG-AFS) , after the ultrasonic extraction with 6 mol/L HCl as extraction reagent. The ultrasonic extraction conditions were optimized, including extraction reagent, time and temperature. Under the optimized experimental condition, arsemc in concentration range of 0. 20-100 μg/L showed linearity to the fluorescence intensity with correlation coefficient of 0. 999 7. The detection limit of arsenic was 0. 025 μg/L. The relative standard deviation (RSD) for 10 μg/L As was 0. 9 % (n=11). The proposed method has been applied to the analysis of coal fly ash component analysis certified reference material (GBW08401) and coal samples with recoveries of 95%-102 %, and the result of GBW08401 was consist with the certified value.%利用6 mol/L盐酸作为提取试剂,样品经超声提取后,用顺序注射氢化物发生-原子荧光光谱法测定煤中无机砷的含量.对超声提取条件(提取试剂浓度、时间、温度)进行了优化.在优化的实验条件下,砷的浓度在0.20~100μg/L范围内与荧光强度呈线性关系,相关系数为0.999 7,砷的检出限为0.025μg/L,对10 μg/L砷标准溶液进行重复11次测量,得出相对标准偏差(RSD)为0.9%.用该法对煤飞灰成分分析标准物质GBW08401和煤样进行分析,测得回收率在95%~102%之间,标准样品的测定值和认定值相符.

  17. 氢化物发生-原子荧光光谱法直接测定土壤水溶态Sb(Ⅲ)和Sb(Ⅴ)%Direct Determination of Water-Soluble Antimony(Ⅲ) and Antimony(Ⅴ) in Soil by Hydride Generation Atomic Fluorescence Spectrometry

    Institute of Scientific and Technical Information of China (English)

    于兆水; 张勤

    2009-01-01

    在HCl介质中,Sb(Ⅲ)和Sb(Ⅴ)在氢化物发生过程中的化学反应效率不同,通过测定经还原剂还原后和还原前Sb的荧光强度,求解联立方程计算出Sb(Ⅲ)和Sb(Ⅴ)的含量,据此建立了氧化物发生-原子荧光光谱法直接测定土壤水溶态Sb(Ⅲ)和Sb(Ⅴ)方法,操作简便,实用性强.考察了 HCl浓度和KBH_4浓度对Sb(Ⅲ)和Sb(Ⅴ)测定灵敏度的影响以及共存元素的干扰情况,并比较了丽种还原剂对Sb(Ⅴ)的还原效果.方法检出限为Sb(Ⅲ)1.11 ng·g~(-1),Sb(Ⅴ)1.57 ng·g~(-1).加标回收试验表明方法准确、可靠.%A simple, rapid and useful method for the determination of water-soluble antimony( Ⅲ ) and antimony(Ⅴ) in soil was established using hydride generation atomic fluorescence spectrometry. The method was based on the different chemical reaction efficiency between Sb( Ⅲ ) and Sb( Ⅴ ) with KBH_4 in the media of HCL The amounts of Sb( Ⅲ) and Sb( Ⅴ ) can be obtained through measuring antimony fluorescence intensities before and after reduction with reductant. The effects of HCI and KBH_4 on the sensitivities of Sb(Ⅲ) and Sb(Ⅴ) were investigated, and the interferences from coexistent elements were studied. The re-duction efficiencies of both reductants were compared. The detection limits of the method were 1.11 ng·g~(-1) for Sb( Ⅲ ) and 1.57 ng·g~(-1) for Sb( Ⅴ ). The accuracy of the method was verified by recovery experiments on spiked real soil samples.

  18. Atomic phase diagram

    Institute of Scientific and Technical Information of China (English)

    LI Shichun

    2004-01-01

    Based on the Thomas-Fermi-Dirac-Cheng model, atomic phase diagram or electron density versus atomic radius diagram describing the interaction properties of atoms of different kinds in equilibrium state is developed. Atomic phase diagram is established based on the two-atoms model. Besides atomic radius, electron density and continuity condition for electron density on interfaces between atoms, the lever law of atomic phase diagram involving other physical parameters is taken into account, such as the binding energy, for the sake of simplicity.

  19. 甲基异丁基甲酮萃取—氢化物发生原子荧光光谱法测定锑锭和氧化锑中汞%Determination of mercury in antimony ingot and antimony oxide by methyl isobutyl ketone extraction-hydride generation atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    陆建平; 谭芳维; 石建荣

    2012-01-01

    After the samples were dissolved in aqua regia/HBr and tartaric acid was added to mask antimony, then mercury in antimony ingot and antimony oxide was extracted into the organic phase with methyl isobutyl ketone (MIBK) and determined by organic phase injection-intermittent flow injection atomic fluorescence spectrometry. Sample dissolution methods and interferences caused by coexisting ions were investigated, and instrument working conditions, extraction conditions, acidity and other factors were optimized. The results showed that under optimal conditions, the mercury content within the range of 0. 02 to 50 μg/L was in good linear relationship, and the detection limit was 0. 013 jxg/L. This method was applied to the actual antimony ingot and antimony oxide sample analysis. It was found that the results were consistent with those obtained by inductive coupled plasma atomic emission spectrometry with relative standard deviations (RSDs, n = 6) of 0. 65%-2. 4% and recoveries of 94 %-99%.%采用王水/HBr溶解样品,酒石酸掩蔽锑,用甲基异丁基甲酮(MIBK)将汞萃取到有机相中,建立了有机相进样—断续流动注射原子荧光光谱法测定锑锭和氧化锑中汞含量的方法.研究了溶样方法和共存离子可能引起的干扰,优化了仪器工作条件、萃取条件、酸度及其他影响因素.结果表明,在最佳条件下,汞含量在0.02~50 μg/L范围内线性关系良好,方法检出限为0.013 μg/L.将方法应用于锑锭和氧化锑实际样品分析,测得结果与电感耦合等离子体原子发射光谱法一致,相对标准偏差(RSD,n=6)在0.65%~2.4%之间,加标回收率为94%~99%.

  20. Cold Matter Assembled Atom-by-Atom

    CERN Document Server

    Endres, Manuel; Keesling, Alexander; Levine, Harry; Anschuetz, Eric R; Krajenbrink, Alexandre; Senko, Crystal; Vuletic, Vladan; Greiner, Markus; Lukin, Mikhail D

    2016-01-01

    The realization of large-scale fully controllable quantum systems is an exciting frontier in modern physical science. We use atom-by-atom assembly to implement a novel platform for the deterministic preparation of regular arrays of individually controlled cold atoms. In our approach, a measurement and feedback procedure eliminates the entropy associated with probabilistic trap occupation and results in defect-free arrays of over 50 atoms in less than 400 ms. The technique is based on fast, real-time control of 100 optical tweezers, which we use to arrange atoms in desired geometric patterns and to maintain these configurations by replacing lost atoms with surplus atoms from a reservoir. This bottom-up approach enables controlled engineering of scalable many-body systems for quantum information processing, quantum simulations, and precision measurements.

  1. 人血和尿中锡的高压微波络合消解氢化物发生-原子荧光测定法%Determination of tin in human blood and urine with high-pressure microwave digestion and complexing ligand and hydride generation-atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    陈峰; 谢超

    2013-01-01

    Objective To establish the hydride generation-atomic fluorescence spectrometric method for the determination of tin in human blood and urine with high-pressure microwave digestion and complexing ligand.Methods Human blood and urine samples were digested by using high-pressure microwave.Then complexing ligand 1% EDTA,5 ml 150 g/L thiourea and ascorbic acid were added to mask the interfering ions such as nickel,iron,arsenic,selenium and etc.Tin concentration was determined with hydride-generation atomic fluorescence spectrometric method with sodium borohydride as the reductant in 2% sulphuric acid media.Results The linear range of tin was 10-100 μg/ml,the regression equations and correlation coefficients in blood and urine were y=9.391 1 x-16.312,r=0.999 7,y=8.244 7x-27.849 6,r=0.998 2,respectively.The limits of detection of tin in blood and urine were 0.090,0.020 μg/L respectively.The relative standard derivation of this method was 1.4%-6.1%.The rates of recovery were between 98.1% and 101.8%.Conclusion This method presents many advantages,such as completed sample digestion,rapid,less matrix disturbance,accurate,sensitive and is applicable to the determination of tin in blood and urine in grass-roots units.%目的 建立人血、尿中锡的高压微波络合消解氢化物发生-原子荧光测定法.方法 利用高压微波络合消解已加入1% EDTA溶液的人血和尿液,在样品测定液中加入150 g/L硫脲-抗坏血酸5ml来掩蔽镍、铁、砷、硒等干扰离子;以2%硫酸作为介质,以2%的硼氢化钠溶液作为还原剂,采用氢化物发生-原子荧光法测定锡浓度.结果 在10~100 μg/ml的线性范围内,血中锡所得回归方程为y=9.391 1x-16.312,r=0.999 7;尿中锡所得回归方程为y=8.244 7x-27.849 6,r=0.998 2.血、尿中锡的检出限分别为0.090、0.020 μg/L.该方法的RSD为1.4%~6.1%,回收率在98.1%~101.8%之间.结论 该方法样品消解完全,测定时间短,待测元素

  2. PT-GC-CAFS联用技术测定污水处理厂外排水中烷基汞残留量%Determination of the Alkyl Mercury Residue in External Drainage of Partial of Sewage Treatment Plants by Purging Capture-Gas Chromatography-Cold Atomic Fluorescence Spectrometry

    Institute of Scientific and Technical Information of China (English)

    高兰兰; 徐浩; 杨琼; 戴刚

    2016-01-01

    建立了吹扫捕集-气相色谱-冷原子荧光( PT-GC-CAFS)联用技术、多功能自动进样器进样测定污水处理厂外排水中烷基汞残留量的方法. 用烷基化试剂直接衍生,吹扫捕集吸附/富集,以PEG20M填充柱为分离柱,用冷原子荧光作为检测器进行测定,整体分析工作在10 min内完成. 在所选实验条件下,方法对所测甲基汞、乙基汞的线性相关系数分别为0.999 9、1.000,最低检出限分别为0.002、0.003 ng/L,相对标准偏差为1.4% ~10.2%,2.3% ~9.7%;在不同质量浓度水平上进行加标回收率实验,甲基汞的回收率为93.7% ~101.7%,乙基汞为94.1% ~103.6%. 该方法用于污水处理厂外排水中烷基汞残留量的分析测定,结果令人满意.%A confirmative method was developed with purge and trap-GC separation-cold atomic fluorescence spectrophotometer ( PT-GC-CAFS) to detect the residues of alkyl mercury in external drainage of sewage treatment plants by multifunctional automatic sampler. Using direct derivative alkyl mercury by Alkylating reagent, adsorption/enrichment by PT, with PEG20M packed column for separation column, and with cold atomic fluorescence spectrophotometer as a detector to detect mercury in environmental water samples, the overall analysis of the work to be done within 10 min. The method showed that good linear correlation coefficient of methyl mercury′s and ethyl mercury′s was 0.999 9 and 1.000, the relative standard deviation was (RSD=1.4%-10.2%) and ( RSD=2.3%-9.7%) , respectively. With different quality levels to Standard addition recovery test sample, the recovery rate of methyl mercury was 93.7%-101.7%, ethyl mercury was 94.1%-103.6%. The method was applied to determine the alkyl mercury residue in external drainage samples of sewage treatment plants. The results were satisfactory.

  3. Strong Correlation of Fluorescence Photons without Quantum Interference

    Institute of Scientific and Technical Information of China (English)

    HU Xiang-Ming; WANG Fei

    2007-01-01

    It has been predicted that a driven three-level V atom can emit strongly correlated fluorescence photons in the presence of quantum interference. Here we examine the effects of quantum interference on the intensity correlation of fluorescence photons emitted from a driven three-level A atom. Unexpectedly, strong correlation occurs without quantum interference. The quantum interference tends to reduce the correlation function to a normal level. The essential difference between these two cases is traced to the different effects of quantum interference on coherent population trapping (CPT). For the V atom, quantum interference and coherent excitation combine to lead to CPT. For the A atom, however, the quantum interference tends to spoil CPT while the coherent excitation induces the effect.

  4. 微波消解-氢化物原子荧光光谱法测定粤东地区海产品中砷的研究%Determination of Arsenic in Seafood by Hydride Generation-atomic Fluorescence Spectrometry Combined with Microwave Oven Digestion

    Institute of Scientific and Technical Information of China (English)

    蔡龙飞; 徐春秀; 张应钦; 邱新红

    2011-01-01

    [目的]建立一种测定海产品中微量砷的有效方法.[方法]采用微波消解-氢化物原子荧光光谱法测定了粤东地区海产品中砷的含量.[结果]砷在1.0~50.0μg/L范围内线性关系良好,相关系数为0.995,方法的检出限为0.02107μg/L,相对标准偏差为0.932%.部分海产品的含砷量超过国家标准,其超标原因可能与沿海地区的工业污染有关.[结论]该方法试剂用量少、污染小、简便、快速、准确,适于各类海产品中砷含量的检测.%[Objective] The aim was to establish an effective determination method of arsenic in seafood. [Method] Contents of arsenic in seafood samples from eastern Guangdong area were determined by hydride generation-atomic fluorescence spectrometry combined with microwave oven digestion. [Result] The linear range for detection of arsenic was 1.0- 50.0 μg/L, which showed a good linear relationship,and its correlation coefficient was 0.995. The detection limit and relative standard deviation were 0.021 07 μg/L and 0.932% .respectively. Contents of arsenic in some seafood samples were more than the national standard,which could be caused by industrial pollution in coastal areas. [Conclusion] The method is simple,rapid and accurate,so it is applied to the determination of arsenic in seafood samples.

  5. Determination of As,Hg and Cd in FAPAS Canned Fish in UK by Hydride Generation-Atomic Fluorescence Spectrometry%氢化物-原子荧光光谱法测定英国FAPAS鱼罐头中砷汞镉

    Institute of Scientific and Technical Information of China (English)

    叶海辉; 谢德芳; 谢轶; 吴学进

    2012-01-01

    [Objective] To prove that the determination of As, Hg and Cd by the hydride generation-atomic fluorescence spectrometry (HG-AFS) has reached the international level of advanced detection instrument. [ Method] The parameters and testing methods of the HG-AFS were optimized. Through the testing of samples and the recovery test, a set of methods were established for determining the three elements in FAPAS canned fish. [Result] By comparing the detection report provided by FAPAS with the results of multiple laboratories, the Z value was -0.2 for As, 0. 5 for Hg, and 0.4 for Cd, the evaluation of results was satisfactory. [ Conclusion] It is feasible'to apply the HG-AFS method for the determination of As, Hg and Cd in seafood products.%[目的]证实原子荧光仪对这砷汞镉3种元素的检测已达到国际先进检测仪器的水平.[方法]利用氢化物-原子荧光光谱法,优化仪器条件参数和试验方法,通过测试质控样品与加标回收试验,建立一套测试英国FAPAS鱼罐头中砷汞镉的方法.[结果]根据FAPAS提供回来的检测报告,与全球众多实验室比对的结果为:砷的Z值为-0.2,汞的Z值为0.5,镉的Z值为0.4,对结果的评价为很满意.[结论]应用氢化物-原子荧光光谱法对海产品中砷汞镉进行检测是可行的.

  6. Method of trivalent chromium concentration determination by atomic spectrometry

    Science.gov (United States)

    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.

  7. Different Algorithms for Improving Detection Power of Atomic Fluorescence Spectrometry

    Directory of Open Access Journals (Sweden)

    Jian Cui

    2012-11-01

    Full Text Available The purpose of detecting trace concentrations of analytes often is hindered by occurring noise in the signal curves of analytical methods. This is also a problem when different arsenic species (organic arsenic species such as arsanilic acid, nitarsone and roxarsone are to be determined in animal meat by HPLC-UV-HG-AFS, which is the basis of this work. In order to improve the detection power, methods of signal treatment may be applied. We show a comparison of convolution with Gaussian distribution curves, Fourier transform, and wavelet transform. It is illustrated how to estimate decisive parameters for these techniques. All methods result in improved limits of detection. Furthermore, applying baselines and evaluating peaks thoroughly is facilitated. However, there are differences. Fourier transform may be applied, but convolution with Gaussian distribution curves shows better results of improvement. The best of the three is wavelet transform, whereby the detection power is improved by factors of about 2.4

  8. Atomic hydrogen behaviour in Heliotron E

    Energy Technology Data Exchange (ETDEWEB)

    Muraoka, K.; Uchino, K.; Kajiwara, T.; Matsuo, K.; Honda, C.; Suehiro, Y.; Yano, N.; Takeda, K.; Hagiwara, H.; Akazaki, M. (Kyushu Univ., Fukuoka (Japan). Dept. of Energy Conversion); Maeda, M.; Okada, T. (Kyushu Univ., Fukuoka (Japan). Dept. of Electrical Engineering); Sudo, S.; Kondo, K.; Mizuuchi, T.; Sano, F.; Sato, M.; Zushi, H.; Obiki, T. (Kyoto Univ., Uji (Japan). Plasma Physics Lab.); Matsuura, H. (Osaka Prefectural Univ., Sakai (Japan). Dept. of Mechanical Engineering)

    1990-12-01

    In order to understand atomic hydrogen behaviour and particle confinement properties in Heliotron E plasmas, techniques of laser induced fluorescence (LIF) have been extensively used, combined with measurements of absolute Balmer alpha emissions and density fluctuations. The results revealed that for an average electron density anti n{sub e}>1.5x10{sup 19} m{sup -3}, H{alpha} fluorescence allowed the measurements of atomic hydrogen densities and yielded the recycled Franck-Condon neutrals ({approx equal} 3 eV) to penetrate into core plasmas, whereas for anti n{sub e}<1.0x10{sup 19} m{sup -3}, such measurements were perturbed by dissociative-excitation of H{sub 2} molecules into the n=2 state. Also, the global confinement times showed a clear correlation with electron density fluctuations. (orig.).

  9. Fluorescence antibunching microscopy

    CERN Document Server

    Schwartz, Osip

    2011-01-01

    Breaking the diffraction limit in microscopy by utilizing quantum properties of light has been the goal of intense research in the recent years. We propose a quantum superresolution technique based on non-classical emission statistics of fluorescent markers, routinely used as contrast labels for bio-imaging. The technique can be readily implemented using standard fluorescence microscopy equipment.

  10. Fluorescence of atopic allergens

    NARCIS (Netherlands)

    Berrens, L.

    1967-01-01

    Purified atopic allergens have been found to emit flue fluorescence upon irradiation with ultraviolet light of 365 mμ wavelength. The maximum of fluorescence is in the region 445–490 mμ and the intensity is of the same order of magnitude for different atopic allergens. Synthetic model compounds, inc

  11. Fluorescent Lamp Replacement Study

    Science.gov (United States)

    2017-07-01

    Light-emitting diode, LED, lighting, fluorescent, waste reduction, energy conservation, net zero , mercury 16. SECURITY CLASSIFICATION OF: 17. LIMITATION...Center (ATC) to assess the benefits of converting fluorescent tube lighting to light-emitting diode (LED) technology. The report documents the waste ...1-15 SECTION 2. SUBTESTS 2.1 HAZARDOUS WASTE REDUCTION

  12. LEDs for fluorescence microscopy

    NARCIS (Netherlands)

    Young, I.T.; Garini, Y.; Dietrich, H.R.C.; Van Oel, W.; Liqui Lung, G.

    2004-01-01

    Traditional light sources for fluorescence microscopy have been mercury lamps, xenon lamps, and lasers. These sources have been essential in the development of fluorescence microscopy but each can have serious disadvantages: lack of near monochromaticity, heat generation, cost, lifetime of the light

  13. Deconvolution of calcium fluorescent indicator signal from AFM cantilever reflection.

    Science.gov (United States)

    Lopez-Ayon, G Monserratt; Oliver, David J; Grutter, Peter H; Komarova, Svetlana V

    2012-08-01

    Atomic force microscopy (AFM) can be combined with fluorescence microscopy to measure the changes in intracellular calcium levels (indicated by fluorescence of Ca²⁺ sensitive dye fluo-4) in response to mechanical stimulation performed by AFM. Mechanical stimulation using AFM is associated with cantilever movement, which may interfere with the fluorescence signal. The motion of the AFM cantilever with respect to the sample resulted in changes of the reflection of light back to the sample and a subsequent variation in the fluorescence intensity, which was not related to changes in intracellular Ca²⁺ levels. When global Ca²⁺ responses to a single stimulation were assessed, the interference of reflected light with the fluorescent signal was minimal. However, in experiments where local repetitive stimulations were performed, reflection artifacts, correlated with cantilever motion, represented a significant component of the fluorescent signal. We developed a protocol to correct the fluorescence traces for reflection artifacts, as well as photobleaching. An added benefit of our method is that the cantilever reflection in the fluorescence recordings can be used for precise temporal correlation of the AFM and fluorescence measurements.

  14. Neutral atom traps.

    Energy Technology Data Exchange (ETDEWEB)

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  15. Single Molecule DNA Detection with an Atomic Vapor Notch Filter

    CERN Document Server

    Uhland, Denis; Widmann, Matthias; Lee, Sang-Yun; Wrachtrup, Jörg; Gerhardt, Ilja

    2015-01-01

    The detection of single molecules has facilitated many advances in life- and material-sciences. Commonly, it founds on the fluorescence detection of single molecules, which are for example attached to the structures under study. For fluorescence microscopy and sensing the crucial parameters are the collection and detection efficiency, such that photons can be discriminated with low background from a labeled sample. Here we show a scheme for filtering the excitation light in the optical detection of single stranded labeled DNA molecules. We use the narrow-band filtering properties of a hot atomic vapor to filter the excitation light from the emitted fluorescence of a single emitter. The choice of atomic sodium allows for the use of fluorescent dyes, which are common in life-science. This scheme enables efficient photon detection, and a statistical analysis proves an enhancement of the optical signal of more than 15% in a confocal and in a wide-field configuration.

  16. Atom Lithography with a Chromium Atomic Beam

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wen-Tao; LI Tong-Bao

    2006-01-01

    @@ Direct write atom lithography is a new technique in which resonant light is used to pattern an atomic beam and the nanostructures are formed when the atoms deposit on the substrate. We design an experiment setup to fabricate chromium nanolines by depositing an atomic beam of 52 Cr through an off-resonant laser standing wave with the wavelength of 425.55 nm onto a silicon substrate. The resulting nanolines exhibit a period of 215 ± 3 nm with height of 1 nm.

  17. Hyperfine Magnetic Anomaly in the Atomic Spectra of the Rare-Earth Elements

    CERN Document Server

    Gangrsky, Yu P; Karaivanov, D V; Kolesnikov, N N; Marinova, K P; Markov, B N; Rostovsky, V S

    2001-01-01

    The constants of the hyperfine splitting in the atomic optical spectra of the rare-earth elements - Nd, Eu, Gd and Lu - were measured. The method of laser resonance fluorescence in the parallel atomic beam was used. The values of the hyperfine magnetic anomaly were determined from the comparison of magnetic dipole constant ratios of the neighbouring odd Z or N isotopes for the different atomic levels. The connection of these values and the parameters of atomic and nuclear structure is discussed.

  18. Atomic and molecular manipulation

    CERN Document Server

    Mayne, Andrew J

    2011-01-01

    Work with individual atoms and molecules aims to demonstrate that miniaturized electronic, optical, magnetic, and mechanical devices can operate ultimately even at the level of a single atom or molecule. As such, atomic and molecular manipulation has played an emblematic role in the development of the field of nanoscience. New methods based on the use of the scanning tunnelling microscope (STM) have been developed to characterize and manipulate all the degrees of freedom of individual atoms and molecules with an unprecedented precision. In the meantime, new concepts have emerged to design molecules and substrates having specific optical, mechanical and electronic functions, thus opening the way to the fabrication of real nano-machines. Manipulation of individual atoms and molecules has also opened up completely new areas of research and knowledge, raising fundamental questions of "Optics at the atomic scale", "Mechanics at the atomic scale", Electronics at the atomic scale", "Quantum physics at the atomic sca...

  19. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    2000-01-01

    This fifth volume of the successful series Advances in Atomic Spectroscopy continues to discuss and investigate the area of atomic spectroscopy.It begins with a description of the use of various atomic spectroscopic methods and applications of speciation studies in atomic spectroscopy. The emphasis is on combining atomic spectroscopy with gas and liquid chromatography. In chapter two the authors describe new developments in tunable lasers and the impact they will have on atomic spectroscopy. The traditional methods of detection, such as photography and the photomultiplier, and how they are being replaced by new detectors is discussed in chapter three. The very active area of glow discharge atomic spectrometry is presented in chapter four where, after a brief introduction and historical review, the use of glow discharge lamps for atomic spectroscopy and mass spectrometry are discussed. Included in this discussion is geometry and radiofrequency power. The future of this source in atomic spectroscopy is also dis...

  20. Microfabricated Waveguide Atom Traps.

    Energy Technology Data Exchange (ETDEWEB)

    Jau, Yuan-Yu

    2017-09-01

    A nano - scale , microfabricated waveguide structure can in - principle be used to trap atoms in well - defined locations and enable strong photon - atom interactions . A neutral - atom platf orm based on this microfabrication technology will be pre - aligned , which is especially important for quantum - control applications. At present, there is still no reported demonstration of evanescent - field atom trapping using a microfabricated waveguide structure. We described the capabilities established by our team for future development of the waveguide atom - trapping technology at SNL and report our studies to overcome the technical challenges of loading cold atoms into the waveguide atom traps, efficient and broadband optical coupling to a waveguide, and the waveguide material for high - power optical transmission. From the atomic - physics and the waveguide modeling, w e have shown that a square nano - waveguide can be utilized t o achieve better atomic spin squeezing than using a nanofiber for first time.

  1. Fluorescence and Spectral Imaging

    Directory of Open Access Journals (Sweden)

    Ralph S. DaCosta

    2007-01-01

    Full Text Available Early identification of dysplasia remains a critical goal for diagnostic endoscopy since early discovery directly improves patient survival because it allows endoscopic or surgical intervention with disease localized without lymph node involvement. Clinical studies have successfully used tissue autofluorescence with conventional white light endoscopy and biopsy for detecting adenomatous colonic polyps, differentiating benign hyperplastic from adenomas with acceptable sensitivity and specificity. In Barrett's esophagus, the detection of dysplasia remains problematic because of background inflammation, whereas in the squamous esophagus, autofluorescence imaging appears to be more dependable. Point fluorescence spectroscopy, although playing a crucial role in the pioneering mechanistic development of fluorescence endoscopic imaging, does not seem to have a current function in endoscopy because of its nontargeted sampling and suboptimal sensitivity and specificity. Other point spectroscopic modalities, such as Raman spectroscopy and elastic light scattering, continue to be evaluated in clinical studies, but still suffer the significant disadvantages of being random and nonimaging. A recent addition to the fluorescence endoscopic imaging arsenal is the use of confocal fluorescence endomicroscopy, which provides real-time optical biopsy for the first time. To improve detection of dysplasia in the gastrointestinal tract, a new and exciting development has been the use of exogenous fluorescence contrast probes that specifically target a variety of disease-related cellular biomarkers using conventional fluorescent dyes and novel potent fluorescent nanocrystals (i.e., quantum dots. This is an area of great promise, but still in its infancy, and preclinical studies are currently under way.

  2. 两行根数辅助的SLR单站定轨%Two Line Element Aided Orbit Determination Using Single Station SLR Data

    Institute of Scientific and Technical Information of China (English)

    梁智鹏; 刘承志; 范存波; 孙明国

    2012-01-01

    It is difficult to use the single-station satellite laser ranging (SLR) data for orbit determination, due to the singular geometrical distribution of the observations. The single-station data generated by performing diffuse-reflection SLR to the orbital space debris are therefore ineffective for orbit improvement.We propose a method to resolve the singularity in the observation distribution. Since the initial orbits of space debris such as the two line elements (TLE) exist prior to the SLR tracking, we use it to simulate observations from other SLR sites. We combine the simulated and actual observations with a proper weight to fit an orbit, thus resolving the singularity in the observation distribution. We then propagate the fitted orbit forward in time to validate against the precision ephemeris derived from the international laser ranging service (ILRS).The method is implemented and applied to the satellite Ajisai. Using the single-station SLR data of five passes in one day and corresponding TLE as the initial orbit, we fit the orbit and the generated predictions. The predicted position error is less than 40 meter in five-day span, significantly improved over the initial SGP4 propagated orbit. The method's potential application to space debris orbit improvement is also discussed.%单站测距资料定轨的困难限制了漫反射SLR (Satellite Laser Ranging)测距资料的应用.为此,提出利用两行根数模拟多站SLR测距资料作为辅助,实现单站SLR测距资料定轨的方法.该方法对卫星Ajisai单站SLR测距资料定轨并生成5d预报轨道,误差小于40 m,实现利用单站测距资料的轨道改进,验证了方法的可行性.

  3. Gemcitabine plus nedaplatin as salvage therapy is a favorable option for patients with progressive metastatic urothelial carcinoma after two lines of chemotherapy.

    Science.gov (United States)

    Matsumoto, Kazumasa; Mochizuki, Kohei; Hirayama, Takahiro; Ikeda, Masaomi; Nishi, Morihiro; Tabata, Ken-ichi; Okazaki, Miyoko; Fujita, Tetsuo; Taoka, Yoshinori; Iwamura, Masatsugu

    2015-01-01

    This study was conducted to evaluate the effectiveness of a combination of gemcitabine and nedaplatin therapy among patients with metastatic urothelial carcinoma previously treated with two lines of chemotherapy. Between February 2009 and August 2013, 30 patients were treated with gemcitabine and paclitaxel as a second-line chemotherapy. All had received a first-line chemotherapy consisting of methotrexate, vinblastine, doxorubicin and cisplatin. Ten patients who had measurable histologically proven advanced or metastatic urothelial carcinoma of the urinary bladder and upper urinary tract received gemcitabine 1,000 mg/m2 on days 1, 8 and 15 and nedaplatin 70 mg/m2 on day 2 as a third-line chemotherapy. Tumors were assessed by imaging every two cycles. The median number of treatment cycles was 3.5. One patient had partial response and three had stable disease. The disease-control rate was 40%, the median overall survival was 8.8 months and the median progression-free survival was 5.0 months. The median overall survival times for the first-line and second-line therapies were 29.1 and 13.9 months, respectively. Among disease-controlled patients (n=4), median overall survival was 14.2 months. Myelosuppression was the most common toxicity. There were no therapy-related deaths. Gemcitabine and nedaplatin chemotherapy is a favorable third-line chemotherapeutic option for patients with metastatic urothelial carcinoma. Given the safety and benefit profile seen in this study, further prospective trials are warranted given the implications of our results with regard to strategic chemotherapy for patients with advanced or metastatic urothelial carcinoma.

  4. Importance of chemical binding type between As and iron-oxide on bioaccessibility in soil: Test with synthesized two line ferrihydrite

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Seulki [Seoul Center, Korea Basic Science Institute, 6-7, Inchon-ro 22-gil, Seongbuk-gu, Seoul 02855 (Korea, Republic of); Yang, Kyung [Division of Public Infrastructure Assessment, Environmental Assessment Group, Korea Environmental Institute, Sejong 30147 (Korea, Republic of); Jho, Eun Hea [Department of Environmental Science, Hankuk University of Foreign Studies, 81 Oedae-ro, Mohyeonmyeon, Cheoin-gu, Yongin-si, Gyeonggi-do 17035 (Korea, Republic of); Nam, Kyoungphile, E-mail: kpnam@snu.ac.kr [Department of Civil and Environmental Engineering, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 08826 (Korea, Republic of)

    2017-05-15

    Highlights: • Arsenic (As)-adsorbed and As-coprecipiated two-line ferrihydrites were synthesized. • Bioaccessibility was closely related to chemical binding type of As in Fe oxide. • Chemical binding type needs to be considered to characterize the risk of As in soil. - Abstract: Bioaccessible concentrations of As associated with Fe oxide as different chemical binding types were determined in soils using the in vitro Physiologically Based Extraction Test (PBET). When compared to the five-step sequential extraction data, most of the As extracted by in vitro PBET originated from the amorphous Fe oxide-bound fraction, and more importantly, the bioaccessibility of As ranged from 0 to 58.8% in 24 soil samples. Two batches of ferrihydrite were synthesized separately. For one batch, As was adsorbed onto the ferrihydrite after synthesis; for the other one, As was added while synthesizing ferrihydrite to co-precipitate. The bioaccessible concentration of As determined by in vitro PBET of the former was 415 mg of As/kg of ferrihydrite and that of the latter was 67 mg of As/kg of ferrihydrite. X-ray photoelectron spectra (XPS) analysis indicated that As–O–Fe bonds were evident in As-associated ferrihydrite sample and especially, As was found within the Fe oxide lattice in the co-precipitated sample. Our data suggest that binding type between As and Fe oxide should be considered when determining the bioaccessibility of As in soil, which, in turn, greatly influences the realistic risk of As present in soil.

  5. Atomic Particle Detection, Understanding the Atom Series.

    Science.gov (United States)

    Hellman, Hal

    This booklet is one of the booklets in the "Understanding the Atom Series" published by the U. S. Atomic Energy Commission for high school science teachers and their students. The instruments used to detect both particles and electromagnetic radiation that emerge from the nucleus are described. The counters reviewed include ionization chambers,…

  6. Highly thermostable fluorescent proteins

    Science.gov (United States)

    Bradbury, Andrew M [Santa Fe, NM; Waldo, Geoffrey S [Santa Fe, NM; Kiss, Csaba [Los Alamos, NM

    2012-05-01

    Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

  7. Highly thermostable fluorescent proteins

    Science.gov (United States)

    Bradbury, Andrew M.; Waldo, Geoffrey S.; Kiss, Csaba

    2011-03-22

    Thermostable fluorescent proteins (TSFPs), methods for generating these and other stability-enhanced proteins, polynucleotides encoding such proteins, and assays and method for using the TSFPs and TSFP-encoding nucleic acid molecules are provided. The TSFPs of the invention show extremely enhanced levels of stability and thermotolerance. In one case, for example, a TSFP of the invention is so stable it can be heated to 99.degree. C. for short periods of time without denaturing, and retains 85% of its fluorescence when heated to 80.degree. C. for several minutes. The invention also provides a method for generating stability-enhanced variants of a protein, including but not limited to fluorescent proteins.

  8. Dynamics Resonances in Atomic States of Astrophysical Relevance

    Indian Academy of Sciences (India)

    K. N. Arefieff; K. Miculis; N. N. Bezuglov; M. S. Dimitrijević; A. N. Klyucharev; A. A. Mihajlov; V. A. Srećković

    2015-12-01

    Ionized geocosmic media parameters in a thermal and a subthermal range of energy have a number of unique features. The photoresonance plasma that is formed by optical excitation of the lowest excited (resonance) atomic states is one example of conversion of radiation energy into electrical one. Since spontaneous fluorescence of excited atoms is probabilistic, the description of the radiating quantized system evolution along with photon energy transfer in a cold atom medium, should include elements of stochastic dynamics. Finally, the chaotic dynamics of a weakly bound Rydberg electron over a grid of the energy level diagram of a quasi-molecular Rydberg complex provides an excitation migration of the electron forward to the ionization continuum. This work aims at discussing the specific features of the dynamic resonances formalism in the description of processes involving Rydberg states of an excited atom, including features in the fluorescence spectrum partially caused by the quantum defect control due to the presence of statistic electromagnetic fields.

  9. Dynamics Resonances in Atomic States of Astrophysical Relevance

    CERN Document Server

    Arefieff, K N; Bezuglov, N N; Dimitrijevic, M S; Klyucharev, A N; Mihajlov, A A; Sreckovic, V A

    2016-01-01

    Ionized geocosmic media parameters in a thermal and a subthermal range of energy have a number of unique features. The photoresonance plasma that is formed by optical excitation of the lowest excited (resonance) atomic states is one example of conversion of radiation energy into electrical one. Since spontaneous fluorescence of excited atoms is probabilistic, the description of the radiating quantized system evolution along with photons energy transfer in a cold atoms medium, should include elements of stochastic dynamics. Finally, the chaotic dynamics of a weakly bound Rydberg electron over a grid of the energy levels diagram of a quasi-molecular Rydberg complex provides an excitation migration of the electron forward to the ionization continuum. This work aims at discussing the specific features of the dynamic resonances formalism in the description of processes involving Rydberg states of an excited atom, including features in the fluorescence spectrum partially caused by the quantum defect control due to ...

  10. Cooperative effects and slow dynamics of fluorescence intensity from quantum emitters in a dielectric

    Science.gov (United States)

    Lozing, N. A.; Gladush, M. G.

    2016-12-01

    We study theoretically the possibility of spontaneous switching between dim and bright fluorescence modes from a cooperative ensemble of two-level atoms driven by a cw-laser. A numerical analysis of transient regimes and transformations of the fluorescence spectrum are reported.

  11. Introduction to fluorescence

    CERN Document Server

    Jameson, David M

    2014-01-01

    "An essential contribution to educating scientists in the principles of fluorescence. It will also be an important addition to the libraries of practitioners applying the principles of molecular fluorescence."-Ken Jacobson, Kenan Distinguished Professor of Cell Biology and Physiology, University of North Carolina at Chapel Hill"An exquisite compendium of fluorescence and its applications in biochemistry enriched by a very exciting historical perspective. This book will become a standard text for graduate students and other scientists."-Drs. Zygmunt (Karol) Gryczynski and Ignacy Gryczynski, University of North Texas Health Science Center"… truly a masterwork, combining clarity, precision, and good humor. The reader, novice or expert, will be pleased with the text and will not stop reading. It is a formidable account of the fluorescence field, which has impacted the life sciences so considerably in the last 60 years."-Jerson L. Silva, M.D., Ph.D., Professor and Director, National Institute of Science and Tech...

  12. 超声波水浴辅助消解-原子荧光光谱法测定食用菌中硒含量%Determination of Selenium in Edible Mushrooms by Ultrasonic Assisted Water Bath Digestion-Atomic Fluorescence Spectrometry

    Institute of Scientific and Technical Information of China (English)

    吴庆晖; 黄伯熹; 冉文清; 荀合; 魏强; 李正全; 陈泳

    2012-01-01

    A method to determine selenium in edible mushroom was developed using ultrasonic assisted water bath digestion followed by atomic fluorescence spectrometry (AFS). The optimum instrumental parameters were established using an orthogonal array design. Besides, the effects of digestion methods and digestion in the presence or absence of potassium ferricyanide on the results of AFS were investigated. AFS was used to determine the selenium contents of different edible mushrooms and the causes of selenium enrichment and the food safety were analyzed based on the results obtained. The limit of detection of the AFS method was 0.20 ng/mL. The sample pretreatment was more efficient and the results of AFS obtained using ultrasonic assisted water bath digestion showed no significant differences compared with wet digestion. AFS can provide a rapid and accurate to analyze selenium in edible mushroom.%为提高检测效率,建立超声波水浴辅助消解.原子荧光光谱法测定食用菌中硒含量的方法。对仪器实验条件进行正交试验优化,对样品前处理方法、铁氰化钾的影响和方法选择性等影响因素进行研究,根据样品检测结果进行原因分析及安全性评价。该方法检出限为0.20ng/mL,加标回收率为91.6%-102.7%。与国标方法对照,提高了样品前处理效率且结果无显著性差异,为食用菌中硒的检测与质量控制提供了一种快速、准确的分析方法。

  13. Purge and Trap Gas Chromatography-Cold Vapor Atomic Fluorescence Spectrometry Determination of Methyl Mercury and Ethyl Mercury in Marine Animals%P & T-GC-CVAFS法测定海产动物中的甲基汞和乙基汞

    Institute of Scientific and Technical Information of China (English)

    崔颖; 肖亚兵; 王禹; 高健会

    2016-01-01

    Marine animals sample was extracted with 30%nitric acid solution , and then adjusted the pH with 2 mol/L sodium acetate-acetic acid buffer solution. The eluate obtained was determined and identified by purge and trap gas chromatography-cold vapor atomic fluorescence spectrometry (P&T-GC-CVAFS). The propylation derivatization converted Methyl mercury (MeHg) to the more volatile methyl propyl mercury (MeHgPr), Ethyl mercury(EtHg) to the more volatile ethyl propyl mercury(EtHgPr), which could be concentrated through purge and trap system with a further clean-up of matrix. Tests for recovery were made by addition of standard MeHg and EtHg solutions at 3 different concentration levels to blank marine animals sample matrixes, values of MeHg recovery found were in the range from 80.5%to 103.2%, with RSDs (n=6) in the range from 1.7%to 6.9%;values of EtHg recovery found were in the range from 84.2%to 103.7%, with RSDs(n=6) in the range from 2.3%to 7.0%.%海产动物样品经过30%硝酸溶液提取,用2 mol/L醋酸钠-醋酸缓冲溶液调节pH后,用吹扫捕集-气相色谱-冷原子荧光光谱仪联用系统测定其中的甲基汞和乙基汞的含量。使用衍生试剂,将甲基汞转化为甲基丙基汞,乙基汞转化为乙基丙基汞,吹扫捕集进行富集并进一步消除基体干扰。以空白样品为基体,添加3种浓度水平的甲基汞和乙基汞标准溶液,测得甲基汞的回收率为80.5%~103.2%,相对标准偏差(n=6)为1.7%~6.9%;乙基汞的回收率在84.2%~103.7%,相对标准偏差(n=6)为2.3%~7.0%。

  14. 基于差分吸收激光雷达的一种新的对流层臭氧浓度反演算法%Butanol Extraction Combined with Dilute Hydrochloric Acid Dissolution-Atomic Fluorescence Spectrometric Method for Indirect Determination of Molybdenum in Chinese Herbal Medicine

    Institute of Scientific and Technical Information of China (English)

    范广强; 刘建国; 刘文清; 陆亦怀; 张天舒; 董云升; 赵雪松

    2012-01-01

    A method for indirectly determining the molybdenum in Chinese herbal medicine by butanol extraction and dilute hydrochloric acid dissolution was established for atomic fluorescence spectrometry. The molybdoarsenate heteropoly acid, formed in the presence of As( V) and ammonium molybdate in 0. 3 mol · L-1 sulphuric acid medium, was separated and enriched in the organic solvent, then the evaporation of organic reagent was implemented and the left residue was dissolved in dilute hydrochloric acid in which the arsenic content was determined on behalf of molybdenum. In the optimum experimental conditions, molybdenum content in 0~15 μg · L-1 range depicts a good linear relationship, the detection limit and relative standard deviation of 0. 44 μg · L-1 and 1.1% were obtained, respectively. Spiked Chinese herbal medicine samples were determined with the proposed method, and recoveries of 95. 6%—101. 3% were achieved.%差分吸收激光雷达探测对流层臭氧浓度时,气溶胶的干扰会造成较大的误差.提出了一种算法,该算法能够同时反演得到对流层臭氧浓度和气溶胶消光系数,减少气溶胶对反演结果的影响.使用实验数据,分析计算了气溶胶雷达比,气溶胶波长指数、标定点气溶胶后向散射比各种变化参数对反演结果的误差.结果表明,1km以下,各种变化参数造成的反演误差小于8%,1km以上臭氧浓度误差主要来源于信号和背景噪声,各种参数反演误差小于3%.最后给出了利用该算法得到对流层臭氧浓度和气溶胶的消光系数垂直廓线,并和传统的双波长差分算法反演结果作了比较分析.实验结果表明该算法是可行的,该算法可以减少气溶胶对差分吸收激光雷达测量结果引起的误差.

  15. Simultaneous Determination of Arsenic and Mercury in Compound Danshen Tablets by Double Channel Atomic Fluorescence Spectrometry%双通道原子荧光法同时测定复方丹参片中砷和汞的含量

    Institute of Scientific and Technical Information of China (English)

    莫迎

    2011-01-01

    目的:建立双通道原子荧光法同时测定复方丹参片中砷和汞的含量.方法:样品采用浓硝酸和过氧化氢混合液进行预消化,再采用微波消解仪在3种条件下进行消化.优化的仪器工作参数:光电倍增管负高压为270 V,砷空心阴极灯总电流为60mA,汞空心阴极灯总电流为30 mA,原子化器高度为8 mm,载气流量为400 ml·min-1,屏蔽气流量为800ml·min-1.结果:本方法砷和汞的线性范围分别为0~60ng·ml-1和0~5 ng·ml-1,相关系数分别为r=0.9998(n=6)和r=0.999 5(n=6),检出限分别为1.38μg·kg-1和0.078μg·kg-1,回收率分别为99.34%和98.38%.结论:本法可用于复方丹参片中砷和汞含量的测定.%Objective: To establish a method for the simultaneous determination of arsenic and mercury in compound Danshen tablets by double channel atomic fluorescence spectrometry.Method: The samples were pre-dissolved by nitric acid and hydrogen peroxide, then digested completely using microwave digestion device under 3 different conditions.The measurement conditions were as the follows: the negative high pressure of photomultiplier tubes was 270 v, total current of As hollow cathode lamp was 60 mA and 30 mA for Hg hollow cathode lamp, height of atomizer was 8 mm, carrier gas flow was 400 ml· min -1 and 800 ml· min -1 for shielding gas.Result: The linear range was 0-60 ng·ml-1 and 0-5 ng·ml -1 for arsenic and mercury with the correlation coefficient of 0.999 8( n =6) and 0.9995 ( n = 6 ), respectively.The detection limit of arsenic and mercury was 1.38 μg· kg - 1 and 0.078 μg · kg - 1, and the recovery was 99.34% and 98.38%, respectively.Conclusion: The method can be used for the simultaneous detection of arsenic and mercury in compound Danshen tablets.

  16. Prospect for detecting squeezed states of light created by a single atom in free space

    OpenAIRE

    Stobińska, Magdalena; Sondermann, Markus; Leuchs, Gerd

    2009-01-01

    We discuss the possibilities of studying in detail the dynamics of spontaneous emission of a single photon by a single atom and measuring the transient degree of squeezing by means of full solid angle fluorescence detection.

  17. Functional Fluorescent Organic Nanoparticles

    OpenAIRE

    Campioli, Elisa

    2013-01-01

    This thesis presents an extensive study on fluorescent organic nanoparticles and fluorescent organic binary and ternary nanoassemblies. In particular the attention is focused on the preparation and characterization of organic nanoparticles and new nanocomposites obtained from different types of small organic molecules, their stabilization and the use of these materials for biological and optoelectronics applications. The work deals at the beginning with the description of some methods used...

  18. Presenting the Bohr Atom.

    Science.gov (United States)

    Haendler, Blanca L.

    1982-01-01

    Discusses the importance of teaching the Bohr atom at both freshman and advanced levels. Focuses on the development of Bohr's ideas, derivation of the energies of the stationary states, and the Bohr atom in the chemistry curriculum. (SK)

  19. Improving the Stability of Fluorescent Silver Nanoclusters

    Science.gov (United States)

    Swanson, Nicholas; Stanko, Danielle; Campbell, Ian; Wittmershaus, Bruce

    The quantum mechanical nature of noble metal nanoparticles results in them having optical properties much different from the bulk metal. Silver nanoclusters (AgNC), groups of 4 to 20 atoms, are characterized by strong optical transitions in the visible part of the spectrum giving them an appearance like fluorescent organic dyes. These nanoclusters can also have fluorescence quantum yields over 90%. Following the analysis of published results of DNA templated nanoclusters, we created a procedure for synthesizing AgNC. The AgNC have a high fluorescence quantum yield but degrade with a lifetime of only a few days when in solution at room temperature. Our goal in this study was to increase the stability of the AgNC towards improving their value as a fluorescent material in various applications, such as luminescent solar concentrators. To increase their stability, we've chosen to modify our procedure by removing oxygen from the solution after the sample has reacted. Oxygen removal caused a significant increase in the stability of the clusters over a given period of time. This material is based upon work supported by the National Science Foundation under Grant Number NSF-ECCS-1306157.

  20. Single Atom Plasmonic Switch

    OpenAIRE

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2015-01-01

    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individ...

  1. Atomic Scale Plasmonic Switch

    OpenAIRE

    Emboras, A.; Niegemann, J.; Ma, P.; Haffner, C; Pedersen, A.; Luisier, M.; Hafner, C.; Schimmel, T.; Leuthold, J.

    2016-01-01

    The atom sets an ultimate scaling limit to Moore’s law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocat...

  2. Atoms Talking to SQUIDs

    CERN Document Server

    Hoffman, J E; Kim, Z; Wood, A K; Anderson, J R; Dragt, A J; Hafezi, M; Lobb, C J; Orozco, L A; Rolston, S L; Taylor, J M; Vlahacos, C P; Wellstood, F C

    2011-01-01

    We present a scheme to couple trapped $^{87}$Rb atoms to a superconducting flux qubit through a magnetic dipole transition. We plan to trap atoms on the evanescent wave outside an ultrathin fiber to bring the atoms to less than 10 $\\mu$m above the surface of the superconductor. This hybrid setup lends itself to probing sources of decoherence in superconducting qubits. Our current plan has the intermediate goal of coupling the atoms to a superconducting LC resonator.

  3. Atomic Storage States

    Institute of Scientific and Technical Information of China (English)

    汪凯戈; 朱诗尧

    2002-01-01

    We present a complete description of atomic storage states which may appear in the electromagnetically induced transparency (EIT). The result shows that the spatial coherence has been included in the atomic collective operators and the atomic storage states. In some limits, a set of multimode atomic storage states has been established in correspondence with the multimode Fock states of the electromagnetic field. This gives a better understanding of the fact that, in BIT, the optical coherent information can be preserved and recovered.

  4. The Nature of Atoms.

    Science.gov (United States)

    Holden, Alan

    This monograph was written for the purpose of presenting physics to college students who are not preparing for careers in physics. It deals with the nature of atoms, and treats the following topics: (1) the atomic hypothesis, (2) the chemical elements, (3) models of an atom, (4) a particle in a one-dimensional well, (5) a particle in a central…

  5. Atomic Spectra Database (ASD)

    Science.gov (United States)

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  6. Observation of single neutral atoms in a large-magnetic-gradient vapour-cell magneto-optical trap

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; He Jun; Qiu Ying; Yang Bao-Dong; Zhao Jiang-Yan; Zhang Tian-Cai; Wang Jun-Min

    2008-01-01

    Single caesium atoms in a large-magnetic-gradient vapour-cell magneto-optical trap have been identified. The trapping of individual atoms is marked by the steps in fluorescence signal corresponding to the capture or loss of single atoms. The typical magnetic gradient is about 29 mT/cm, which evidently reduces the capture rate of magneto-optical trap.

  7. 3D Beam Reconstruction by Fluorescence Imaging

    CERN Document Server

    Radwell, Neal; Franke-Arnold, Sonja

    2013-01-01

    We present a technique for mapping the complete 3D spatial intensity profile of a laser beam from its fluorescence in an atomic vapour. We propagate shaped light through a rubidium vapour cell and record the resonant scattering from the side. From a single measurement we obtain a camera limited resolution of 200 x 200 transverse points and 659 longitudinal points. In constrast to invasive methods in which the camera is placed in the beam path, our method is capable of measuring patterns formed by counterpropagating laser beams. It has high resolution in all 3 dimensions, is fast and can be completely automated. The technique has applications in areas which require complex beam shapes, such as optical tweezers, atom trapping and pattern formation.

  8. Single Atom Plasmonic Switch

    CERN Document Server

    Emboras, Alexandros; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2015-01-01

    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individual or at most - a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ration of 10 dB and operation at room temperature with femtojoule (fJ) power consumption for a single switch operation. This demonstration of a CMOS compatible, integrated quantum device allowing to control photons at the single-atom level opens intriguing perspectives for a fully i...

  9. Nine New Fluorescent Probes

    Science.gov (United States)

    Lin, Tsung-I.; Jovanovic, Misa V.; Dowben, Robert M.

    1989-06-01

    Absorption and fluorescence spectroscopic studies are reported here for nine new fluorescent probes recently synthesized in our laboratories: four pyrene derivatives with substituents of (i) 1,3-diacetoxy-6,8-dichlorosulfonyl, (ii) 1,3-dihydroxy-6,8-disodiumsulfonate, (iii) 1,3-disodiumsulfonate, and (iv) l-ethoxy-3,6,8-trisodiumsulfonate groups, and five [7-julolidino] coumarin derivatives with substituents of (v) 3-carboxylate-4-methyl, (vi) 3- methylcarboxylate, (vii) 3-acetate-4-methyl, (viii) 3-propionate-4-methyl, and (ix) 3-sulfonate-4-methyl groups. Pyrene compounds i and ii and coumarin compounds v and vi exhibit interesting absorbance and fluorescence properties: their absorption maxima are red shifted compared to the parent compound to the blue-green region, and the band width broadens considerably. All four blue-absorbing dyes fluoresce intensely in the green region, and the two pyrene compounds emit at such long wavelengths without formation of excimers. The fluorescence properties of these compounds are quite environment-sensitive: considerable spectral shifts and fluorescence intensity changes have been observed in the pH range from 3 to 10 and in a wide variety of polar and hydrophobic solvents with vastly different dielectric constants. The high extinction and fluorescence quantum yield of these probes make them ideal fluorescent labeling reagents for proteins, antibodies, nucleic acids, and cellular organelles. The pH and hydrophobicity-dependent fluorescence changes can be utilized as optical pH and/or hydrophobicity indicators for mapping environmental difference in various cellular components in a single cell. Since all nine probes absorb in the UV, but emit at different wavelengths in the visible, these two groups of compounds offer an advantage of utilizing a single monochromatic light source (e.g., a nitrogen laser) to achieve multi-wavelength detection for flow cytometry application. As a first step to explore potential application in

  10. Condensed matter applied atomic collision physics, v.4

    CERN Document Server

    Datz, Sheldon

    1983-01-01

    Applied Atomic Collision Physics, Volume 4: Condensed Matter deals with the fundamental knowledge of collision processes in condensed media.The book focuses on the range of applications of atomic collisions in condensed matter, extending from effects on biological systems to the characterization and modification of solids. This volume begins with the description of some aspects of the physics involved in the production of ion beams. The radiation effects in biological and chemical systems, ion scattering and atomic diffraction, x-ray fluorescence analysis, and photoelectron and Auger spectrosc

  11. Stroboscopic fluorescence lifetime imaging.

    Science.gov (United States)

    Holton, Mark D; Silvestre, Oscar R; Errington, Rachel J; Smith, Paul J; Matthews, Daniel R; Rees, Paul; Summers, Huw D

    2009-03-30

    We report a fluorescence lifetime imaging technique that uses the time integrated response to a periodic optical excitation, eliminating the need for time resolution in detection. A Dirac pulse train of variable period is used to probe the frequency response of the total fluorescence per pulse leading to a frequency roll-off that is dependent on the relaxation rate of the fluorophores. The technique is validated by demonstrating wide-field, realtime, lifetime imaging of the endocytosis of inorganic quantum dots by a cancer cell line. Surface charging of the dots in the intra-cellular environment produces a switch in the fluorescence lifetime from approximately 40 ns to technique offers lifetime based imaging at video rates with standard CCD cameras and has application in probing millisecond cell dynamics and in high throughput imaging assays.

  12. The effects of disruptive and stabilizing selection on body size in Drosophila melanogaster. III. Genetic analysis of two lines with different reactions to disruptive selection with mating of opposite extremes

    NARCIS (Netherlands)

    Bos, M.; Scharloo, W.

    1974-01-01

    A genetic analysis was made of two lines which when subjected to disruptive selection with compulsary mating of opposite extremes (D−) showed a different response viz. one, D−-1, showing predominantly an increase of environmental variance and possibly interaction variance, the other, D−-2, showing a

  13. Pioneers: A Case Study of a Film Caught in the Two Line Struggle in Literature and Art in the People's Republic of China. Occasional Paper No. 77-5.

    Science.gov (United States)

    Morrison, Linda

    The controversy surrounding the Chinese film "Pioneers" is analyzed and presented as a case study of a film caught in the recent two-line struggle in literature and art in the People's Republic of China. Within the history of the arts in China, there has been a difference of opinion between those in favor of the continued portrayal of…

  14. Pioneers: A Case Study of a Film Caught in the Two Line Struggle in Literature and Art in the People's Republic of China. Occasional Paper No. 77-5.

    Science.gov (United States)

    Morrison, Linda

    The controversy surrounding the Chinese film "Pioneers" is analyzed and presented as a case study of a film caught in the recent two-line struggle in literature and art in the People's Republic of China. Within the history of the arts in China, there has been a difference of opinion between those in favor of the continued portrayal of…

  15. The effects of disruptive and stabilizing selection on body size in Drosophila melanogaster. III. Genetic analysis of two lines with different reactions to disruptive selection with mating of opposite extremes

    NARCIS (Netherlands)

    Bos, M.; Scharloo, W.

    1974-01-01

    A genetic analysis was made of two lines which when subjected to disruptive selection with compulsary mating of opposite extremes (D−) showed a different response viz. one, D−-1, showing predominantly an increase of environmental variance and possibly interaction variance, the other, D−-2, showing

  16. THz Detection and Imaging using Rydberg Atoms

    Science.gov (United States)

    Wade, Christopher; Sibalic, Nikola; Kondo, Jorge; de Melo, Natalia; Adams, Charles; Weatherill, Kevin

    2016-05-01

    Atoms make excellent electromagnetic field sensors because each atom of the same isotope is identical and has well-studied, permanent properties allowing calibration to SI units. Thus far, atoms have not generally been exploited for terahertz detection because transitions from the atomic ground state are constrained to a limited selection of microwave and optical frequencies. In contrast, highly excited `Rydberg' states allow us access to many strong, electric dipole transitions from the RF to THz regimes. Recent advances in the coherent optical detection of Rydberg atoms have been exploited by a number of groups for precision microwave electrometry Here we report the demonstration of a room-temperature, cesium Rydberg gas as a THz to optical interface. We present two configurations: First, THz-induced fluorescence offers non-destructive and direct imaging of the THz field, providing real-time, single shot images. Second, we convert narrowband terahertz photons to infrared photons with 6% quantum efficiency allowing us to use nano-Watts of THz power to control micro-Watts of laser power on microsecond timescales. Exploiting hysteresis and a room-temperature phase transition in the response of the medium, we demonstrate a latching optical memory for sub pico-Joule THz pulses.

  17. Long range intermolecular forces in triatomic systems: connecting the atom-diatom and atom-atom-atom representations

    OpenAIRE

    2005-01-01

    The long-range forces that act between three atoms are analysed in both atom-diatom and atom-atom-atom representations. Expressions for atom-diatom dispersion coefficients are obtained in terms of 3-body nonadditive coefficients. The anisotropy of atom-diatom C_6 dispersion coefficients arises primarily from nonadditive triple-dipole and quadruple-dipole forces, while pairwise-additive forces and nonadditive triple-dipole and dipole-dipole-quadrupole forces contribute significantly to atom-di...

  18. Oxygen Atom Recombination in Carbon Dioxide Atmospheres

    Science.gov (United States)

    Jamieson, Corey; Garcia, R. M.; Pejakovic, D. A.; Kalogerakis, K. S.

    2009-09-01

    Understanding processes involving atomic oxygen is crucial for the study and modeling of composition, energy transfer, airglow, and transport dynamics in planetary atmospheres. Significant gaps and uncertainties exist in our understanding of the above processes, and often the relevant input from laboratory measurements is missing or outdated. We are conducting experiments to measure the rate coefficients for O + O + CO2 and O + O2 + CO2 recombination and investigate the O2 excited states produced following O-atom recombination. These laboratory measurements are key input for a quantitative understanding and reliable modeling of the atmospheres of the CO2 planets and their airglow. An ArF excimer laser with 193-nm pulsed output radiation is employed to partially photodissociate carbon dioxide. In an ambient-pressure (760 Torr) background of CO2, the O atoms produced recombine in a time scale of a few milliseconds. Detection of laser-induced fluorescence at 845 nm following two-photon excitation near 226 nm monitors the decay of the oxygen atom population. From the temporal evolution of the signal we can extract the rate coefficients for recombination of O + O and O + O2 in the presence of CO2. We also use fluorescence and resonance-enhanced multi-photon ionization techniques to detect the products of the O-atom recombination and subsequent relaxation in CO2. This work is supported by the US National Science Foundation's (NSF) Planetary Astronomy Program. Rosanne Garcia's participation was funded by the NSF Research Experiences for Undergraduates (REU) Program.

  19. XRD Analysis on the Fluorescence Material of Sm Doped Si-Ca-Mg System

    Institute of Scientific and Technical Information of China (English)

    HUANG Qing-Ming

    2007-01-01

    Fluorescence material of Sm doped Si-Ca-Mg system was synthesized by using the method of solid phase reaction at high temperature. The phase composition and crystal structure of this material were analyzed with XRD method for its composition and the existence form of Sm atom. We aimed to exactly determine the phase composition of this fluorescence material and the doping position and environment of rare-earth Sm atom in the system because these factors have significant effects on the properties. The analytical results show that the Sm atoms dope in Ca2O26Si6Sm8 lattice in the form of atomic site-occupation in three different space positions with different occupancy rates. Therefore, based on the XRD analytical results, the fluorescence material of Sm doped Si-Ca-Mg system with high performance can be synthesized.

  20. Nanosecond fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Leskovar, B.

    1985-03-01

    This article is a summary of a short course lecture given in conjunction with the 1984 Nuclear Science Symposium. Measuring systems for nanosecond fluorescence spectroscopy using single-photon counting techniques are presented. These involve systems based on relaxation-type spark gap light pulser and synchronously pumped mode-locked dye lasers. Furthermore, typical characteristics and optimization of operating conditions of the critical components responsible for the system time resolution are discussed. A short comparison of the most important deconvolution methods for numerical analysis of experimental data is given particularly with respect to the signal-to-noise ratio of the fluorescence signal. 22 refs., 8 figs.

  1. Prospects of Optical Single Atom Detection for Nuclear Astrophysics

    Science.gov (United States)

    Singh, Jaideep

    2015-10-01

    We will discuss the prospects of optically detecting single atoms captured in a cryogenic thin film of a noble gas such as neon. This proposed detection scheme, when coupled with a recoil separator, could be used to measure rare nuclear reactions relevant for nuclear astrophysics. In particular, we will focus on the 22Ne(α, n)25Mg reaction, which is an important source of neutrons for the s-process. Noble gas solids are an attractive medium because they are optically transparent and provide efficient, pure, stable, & chemically inert confinement for a wide variety of atomic and molecular species. Atoms embedded inside of noble gas solids have a fluorescence spectrum that is often significantly shifted from its absorption spectrum. This makes possible the detection of individual fluorescence photons against a background of intense excitation light, which can be suppressed using the appropriate optical filters. We will report on our efforts to optically detect single Yb atoms in solid Ne. Yb is an ideal candidate for initial studies because it emits a strong green fluorescence when excited by blue light and it has an atomic structure that very closely resembles that of Mg. This work is supported by funds from Michigan State University.

  2. Effects of external fields, dimension and polarization on the resonance fluorescence of quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Vaseghi, B., E-mail: vaseghi@mail.yu.ac.ir; Razavi, S.M.

    2017-02-01

    In this paper simultaneous effects of external electric and magnetic fields, dimension and polarization on the resonance fluorescence spectrum and photon statistics of a spherical quantum dot with parabolic confinement are investigated. With special attention to the optical scattering processes resonance fluorescence spectrum and second-order correlation function are calculated and plotted for different external parameters. Our results show the occurrence of resonance fluorescence similar to atomic systems and considerable effects of external fields, quantum confinement and light polarization on the resonance fluorescence spectrum and second-order correlation function in the quantum dot systems. The existence of Mollow triplets and photon antibunching are strongly depend on these external agents.

  3. Effects of external fields, dimension and polarization on the resonance fluorescence of quantum dots

    Science.gov (United States)

    Vaseghi, B.; Razavi, S. M.

    2017-02-01

    In this paper simultaneous effects of external electric and magnetic fields, dimension and polarization on the resonance fluorescence spectrum and photon statistics of a spherical quantum dot with parabolic confinement are investigated. With special attention to the optical scattering processes resonance fluorescence spectrum and second-order correlation function are calculated and plotted for different external parameters. Our results show the occurrence of resonance fluorescence similar to atomic systems and considerable effects of external fields, quantum confinement and light polarization on the resonance fluorescence spectrum and second-order correlation function in the quantum dot systems. The existence of Mollow triplets and photon antibunching are strongly depend on these external agents.

  4. Determination of Lead in Tea Garden Soil by Hydride Generation Atomic Fluorescence Spectrometry with Microwave Digestion%微波消解-氢化物发生原子荧光光谱法测定茶园土壤中的铅

    Institute of Scientific and Technical Information of China (English)

    凤海元; 时晓露; 黄勤

    2013-01-01

    样品用王水微波消解浸提,氢化物发生-原子荧光光谱法测定茶园土壤中痕量铅的含量.对样品浸取方法、实验条件、增感剂和共存元素进行了条件实验.结果表明,王水微波消解浸取,铅浸出量最大,减少了试剂用量和环境污染;铁氰化钾-盐酸羟胺体系有显著的增感作用,铁氰化钾在配制溶液时用米糠除去试剂中可能存在的铅,降低了空白;钴、锌、砷、镉等共存离子不干扰铅的测定,通过加入邻菲啰啉-硫氰酸钠消除铁和铜的干扰,提高了铅的回收率.方法检出限为0.65 μg/L,精密度(RSD,n=10)为1.89%,回收率在86.8% ~ 110.4%之间.用土壤标准物质验证,测定值与标准值相符,方法快速准确,适合于大批量样品的分析检测.%The microwave digestion system with aqua regia was developed for the determination of trace lead in tea garden soil using Hydride Generation-Atomic Fluorescence Spectrometry ( HG-AFS). The leaching methods, experimental conditions, booster and coexisting element were optimized. The largest amount of lead was leached out by microwave digestion with aqua regia, which has the advantages of less usage of reagent and less environmental pollution. An appropriate amount of potassium ferricyanide and hydroxylamine hydrochloride improved the hydride generation efficiency of Pb. The lead blank was reduced significantly when Potassium ferricyanide solution was treated with rice husk to remove Pb in the reagent. It was found that Co, Zn, As, and Cd did not interfere with the determination of lead. The addition of 1,10-phenanthroline monohydrate and sodium hydrosulfide could effectively eliminate the interferences from Fe and Cu, which improved the recovery rate of lead. The limit of detection was 0. 65 μg/L and the precision was 1. 89% (n = 10) with recoveries of 86. 8% - 110. 4% for Pb. The reliability of the method has been tested by determination of Pb in the Soils Standard Reference

  5. Determination of Water Soluble As ( Ⅲ ) and As ( Ⅴ ) in Soil by Hydride Generation-Atomic Fluorescence Spectrometry%氢化物发生-原子荧光光谱法测定土壤中水溶态砷(Ⅲ)和砷(Ⅴ)

    Institute of Scientific and Technical Information of China (English)

    于兆水; 张勤; 刘玲

    2012-01-01

    以氢气发生器为氩-氢火焰提供纯净、稳定的氢气,原子荧光光谱法测定土壤中水溶态和可交换态Sb(Ⅲ)和Sb(Ⅴ)已有应用,本研究进一步将此方法用于测定土壤样品中的As(Ⅲ)和As(Ⅴ).在0.3mol/L NaH2PO4 - Na2HPO4缓冲液中,采用氢化物发生-原子荧光光谱法测定土壤中水溶态As(Ⅲ)和总砷的含量,通过差减法计算As(Ⅴ)的含量.实验考察了0.02~0.4 mol/L NaH2PO4 - Na2 HPO4对As(Ⅲ)和As(Ⅴ)测定的影响,结果表明0.3 mol/L NaH2PO4 - Na2HPO4可以有效掩蔽As(Ⅴ).As(Ⅲ)的检出限为2.92 ng/g,总砷的检出限为2.35 ng/g;As(Ⅲ)和As(Ⅴ)的加标回收率分别为96% ~ 104%和101% ~103%.本方法不再依靠化学反应产生氢气来点燃并维持氩氢火焰,可在发生氢化反应的任何介质中测定砷,且不需要考虑酸度问题.方法操作简便,准确度高,能满足大批量样品分析要求.%Based on the determination method of Sb ( HI) and Sb ( V ) in soil, a method for the determination of water soluble As ( M ) and total arsenic in soil has been established by using Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS) in the media of 0. 3 mol/L NaH2PO4-Na2HPO4. An amount of As( V ) was obtained by subtracting As( HI ) from total arsenic. The hydrogen was provided from a hydrogen generator instead of chemical reaction to ignite a H2-Ar flame. Therefore, arsenic in any media was measurable since the arsenic was reduced into AsH3. Effects on the determination of As ( M ) and As ( V ) were investigated for concentrations of NaH2PO4-Na2HPO4 from 0. 02 mol/L to 0. 4 mol/L. The results show As( V ) can be screened by 0. 3 mol/L NaH2PO4-Na2HPO4. The detection limits were 2. 92 ng/g for As( HJ ) and 2. 35 ng/g for total As. The recoveries of As( HI) and As( V ) are 96% - 104% and 101% - 103% , respectively. The method was simple and highly accurate, meeting the requirements for multiple sample analysis.

  6. 水产品中甲基汞测定的液相色谱-原子荧光光谱联用方法的改进%Improvement of the method for methylmercury determination in aquatic products using liquid chromatography online coupled with atomic fluorescence spectrometry

    Institute of Scientific and Technical Information of China (English)

    尚晓虹; 赵云峰; 张磊; 李筱薇; 吴永宁

    2011-01-01

    The improvement method was developed for methylmercury determination using liquid chromatography online coupled with cold vapor atomic fluorescence spectrometry ( LC-CVAFS ). Cysteine was used as complexing agent in mobile phase instead of mercaptoethanol.Under the optimized conditions , baseline separation of mercury species could be achieved within 8 min on a C18 column with a mobile phase of 5% ( V/V ) acetonitrile-1 g/L L-cysteine-50 mmol/L ammonium acetate aqueous solution. The linear range of calibration curve of methyl-mercury was 1 - 50 μg/L and the limit of detection ( S/N = 3 ) for methylmercury was 0.3 μg/L.Ultrasonication assisted hydrochloric acid extraction was used to extract methylmercury from seafood samples. The sample extract was cleaned up by a C18 solid phase extraction ( SPE )cartridge. For validation of the method, certified reference materials and spiked seafood samples were analyzed. The determined methylmercury contents of certified reference materials NIST1566b、BCR464 and GBW10029 agreed well with the certified values. The determined methylmercury values for Food Analysis Performance Assessment Scheme ( FAPAS ) sample 07115 were satisfied. The recoveries of methylmercury in seafood samples at three spiked levels ( 10,50 and 500 μg/kg ) ranged from 89% to 112% , including cooked seafood food. The precision of the method based on relative standard deviation ( RSD ) was not more than 7%. The present method of LC-CV-AFS is accurate, sensitive, simple, and can meet the demand of methylmer-cury determination in seafood.%对本实验室前期建立的食品中甲基汞的液相色谱-原子荧光光谱联用测定方法进行了改进.采用无毒的半胱氨酸代替有毒试剂巯基乙醇作为流动相中的配位剂,流动相组成为5%(v/v)乙腈-1 g/L半胱氨酸-50 mmol/L乙酸铵水溶液,使汞化合物分离时间缩短至8 min.在优化条件下,甲基汞标准曲线的线性范围为1~50 μg/L,检出限(S/V=3)为0/3

  7. Determination of Mercuryalkylide in Water Using High Performance Liquid Chromatography with Hydride Generation Atomic Fluorescence Detection%高效液相色谱-氢化物发生-原子荧光光谱联用技术测定水中烷基汞

    Institute of Scientific and Technical Information of China (English)

    陈邵鹏; 顾海东; 秦宏兵

    2012-01-01

    A method for the determination of Mercury species in both surface water and waste water was established by high performance liquid chromatography ( HPLC ) -hydride generation ( HG) -atomic fluorescence spectrophotometry ( AFS). Sample was extracted by dichloromethane, subsequently back-extracted by mixed extractant containing cysteine and ammonium acetate before HPLC-HG-AFS detection. Under the optimized conditions, both methyl mercury and ethyl mercury responded linearly in the concentration of 1-50μg/L. The recoveries for both standard samples and actual samples were 80%-110%. The relative standard deviations for the determination of methyl and ethylmercury with the concentration of 1μg/L were 5. 2% and 3. 9% , respectively. The detection limits for them were 0.4 ng/L and 0.7 ng/L, respectively with the American EPA methord. The proposed method is of good accuracy, high repeatability, precision, less interferences from impurities and low cost, which is benefit for expanding and applying in the common laboratory.%建立了高效液相色谱(HPLC)-氢化物发生(HG)-原子荧光光谱(AFS)联用技术分析地表水及废水中甲基汞和乙基汞的方法.样品经二氯甲烷萃取,再以半胱氨酸+乙酸铵溶液反萃取富集,并进入高效液相色谱分离,经形态分析预处理装置后,借助原子荧光光谱法检测.在优化分离条件下,甲基汞和乙基汞在1 ~ 50 μg/L范围内呈现良好的线性关系,对于标准水样、地表水和废水实际水样,加标平均回收率均为80% ~ 110%.平行进样7次1μg/L的汞混合标准溶液,甲基汞和乙基汞的色谱峰面积的相对标准偏差分别为5.2%和3.9%,检出限则分别为0.4 ng/L和0.7 ng/L.该检测方法前处理简单、回收率稳定、灵敏度和准确度高、检出限低、杂质干扰少、监测费用低,便于在普通实验室推广和应用.

  8. Determination of arsenic in antimony ingot and antimony trioxide by hydride generation-atomic fluorescence spectrometry%氢化物发生-原子荧光光谱法测定锑锭及三氧化二锑中的砷

    Institute of Scientific and Technical Information of China (English)

    钱光敏; 赵国杏

    2012-01-01

    The antimony slab and antimonous oxide samples were dissolved by sulfuric acid and hydrochloric acid, respectively. The Sb3+ in solution was precipitated with sodium hydroxide to separate trace arsenic from matrix antimony. The thiourea-ascorbic acid was added to reduce As5+ to As3+. Then, the arsenic in antimony slab and antimonous oxide was determined by atomic fluorescence spec-trometry. The hydride generation conditions were investigated: the concentration of reducing agent potassium borohydride was 25 g/L, the determination medium was 20% (V/V) hydrochloric acid, and the dosage of thiourea - ascorbic acid solution was 5 mL. The interference test of coexisting elements showed that, the interference of residual antimony in solution after precipitation could be fully eliminated by adding 1 mL of tartaric acid solution. Other impurity elements in sample did not interfere with the determination of arsenic after adding thiourea-ascorbic acid solution. The detection limit of method was 0. 156 ng/mL. The antimony slab and antimonous oxide samples were analyzed by the proposed method, and the relative standard deviation (RSD) was 0. 95%-1.2%. The determination results were consistent with those obtained by national standard methods.%采用硫酸溶解锑锭样品,盐酸溶解三氧化二锑样品,用氢氧化钠溶液使Sb3+沉淀从而使基体锑与微量砷分离,通过加入硫脲-抗坏血酸将As5+还原成As3+,然后在原子荧光仪上测定锑锭及三氧化二锑中的砷.对氢化物发生条件进行考察,确定还原剂硼氢化钾的浓度为25 g/L、测定介质为20%(V/V)盐酸、硫脲-抗坏血酸溶液用量为5 mL.共存元素干扰试验表明,沉淀后溶液中残留少量锑的干扰在加入1 mL酒石酸溶液后可以完全消除,而样品中其他杂质元素在加入硫脲-抗坏血酸溶液后不干扰砷的测定.方法的检出限为0.156 ng/mL.对锑锭及三氧化二锑样品进行分析,相对标准偏差为0.95%~1.2%,测定

  9. THE DETERMINATION OF ANTIMONY (Ⅲ) AND ANTOMONY (Ⅴ) IN GEOLOGICAL SAMPLES BY HYDRIDE GENERATION-ATOMIC FLUORESCENCE SPECTROMETRY%氢化物发生—原子荧光光谱法测定地质样品中的锑(Ⅲ)和锑(Ⅴ)

    Institute of Scientific and Technical Information of China (English)

    郝志红; 杨帆; 刑夏; 汤志勇; 张勤

    2012-01-01

    A method for the determination of antimony ( Ⅲ ) and antimony ( V ) in geological samples (stream sediments) by hydride generation-atomic fluorescence spectrometry was developed in the paper. 4. 8 mol/L HC1 could be used as the extraclant with ultrasonic-assisted extraction. In the medium of 0. 24 mol/L hydrochloric acid, antimony ( Ⅲ) could be alternatively determined with 6 g/mL sodium citrate as the masking agent for Sb (V). Then antimony ( V ) could be figured out by the subtraction method. The detection limit of the method was 0. 075 × 10 -6 for Sb ( 1) and 0. 097 × 10 -6 for Sb ( V ) , and the relative standard deviation was 1. 1 % and 0. 64% ( n = 11) for 40 ng/mL Sb ( Ⅲ ) and 40 ng/mL Sb( V ) standard solution. The proposed method was applied to the determination of antimony ( Ⅲ) and antimony ( V ) in geological samples, and a comparison between the extraction results and the aqua regia dissolution results shows that the extraction rate of antimony was higher than 80% , the recoveries were in the ranges of 83% - 107% and 98% -114% for Sb ( Ⅲ) and Sb (V) respectively.%提出了一种氢化物发生—原子荧光光谱法测定地质样品(水系沉积物)中Sb(Ⅲ)和Sb(Ⅴ)的方法.选取4.8 mol/L HC1为提取剂,采用超声波辅助提取,以6 g/mL柠檬酸钠作为Sb(Ⅴ)的掩蔽剂,在0.24 mol/L的HC1介质中选择性测定Sb(Ⅲ),用差减法求得Sb(Ⅴ).Sb(Ⅲ)的方法检出限为0.075×10-6,Sb(Ⅴ)的方法检出限为0.097×10-6.对40 ng/mL的Sb(Ⅲ)和Sb(Ⅴ)分别连续测定11次,得到相对标准偏差分别为1.1%和0.64%.应用该方法对地质样品中的Sb(Ⅲ)和Sb(Ⅴ)进行分析测定,并与王水溶解值相比较,该方法测定的总Sb提取率在80%以上,Sb(Ⅲ)和Sb(Ⅴ)的加标回收率分别为83% ~ 107%和98% ~ 114%.

  10. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1997-01-01

    This series describes selected advances in the area of atomic spectroscopy. It is primarily intended for the reader who has a background in atmoic spectroscopy; suitable to the novice and expert. Although a widely used and accepted method for metal and non-metal analysis in a variety of complex samples, Advances in Atomic Spectroscopy covers a wide range of materials. Each Chapter will completely cover an area of atomic spectroscopy where rapid development has occurred.

  11. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1995-01-01

    This series describes selected advances in the area of atomic spectroscopy. It is promarily intended for the reader who has a background in atmoic spectroscopy; suitable to the novice and expert. Although a widely used and accepted method for metal and non-metal analysis in a variety of complex samples, Advances in Atomic Spectroscopy covers a wide range of materials. Each Chapter will completely cover an area of atomic spectroscopy where rapid development has occurred.

  12. The Software Atom

    CERN Document Server

    Javanainen, Juha

    2016-01-01

    By putting together an abstract view on quantum mechanics and a quantum-optics picture of the interactions of an atom with light, we develop a corresponding set of C++ classes that set up the numerical analysis of an atom with an arbitrary set of angular-momentum degenerate energy levels, arbitrary light fields, and an applied magnetic field. As an example, we develop and implement perturbation theory to compute the polarizability of an atom in an experimentally relevant situation.

  13. The Software Atom

    Science.gov (United States)

    Javanainen, Juha

    2017-03-01

    By putting together an abstract view on quantum mechanics and a quantum-optics picture of the interactions of an atom with light, we develop a corresponding set of C++ classes that set up the numerical analysis of an atom with an arbitrary set of angular-momentum degenerate energy levels, arbitrary light fields, and an applied magnetic field. As an example, we develop and implement perturbation theory to compute the polarizability of an atom in an experimentally relevant situation.

  14. Atomicity in Electronic Commerce,

    Science.gov (United States)

    1996-01-01

    tremendous demand for the ability to electronically buy and sell goods over networks. Electronic commerce has inspired a large variety of work... commerce . It then briefly surveys some major types of electronic commerce pointing out flaws in atomicity. We pay special attention to the atomicity...problems of proposals for digital cash. The paper presents two examples of highly atomic electronic commerce systems: NetBill and Cryptographic Postage Indicia.

  15. Atomic homodyne detection of weak atomic transitions.

    Science.gov (United States)

    Gunawardena, Mevan; Elliott, D S

    2007-01-26

    We have developed a two-color, two-pathway coherent control technique to detect and measure weak optical transitions in atoms by coherently beating the transition amplitude for the weak transition with that of a much stronger transition. We demonstrate the technique in atomic cesium, exciting the 6s(2)S(1/2) --> 8s(2)S(1/2) transition via a strong two-photon transition and a weak controllable Stark-induced transition. We discuss the enhancement in the signal-to-noise ratio for this measurement technique over that of direct detection of the weak transition rate, and project future refinements that may further improve its sensitivity and application to the measurement of other weak atomic interactions.

  16. Highly luminescent N-doped carbon quantum dots as an effective multifunctional fluorescence sensing platform.

    Science.gov (United States)

    Qian, Zhaosheng; Ma, Juanjuan; Shan, Xiaoyue; Feng, Hui; Shao, Linxiang; Chen, Jianrong

    2014-02-17

    The doping of carbon quantum dots with nitrogen provides a promising direction to improve fluorescence performance and broaden their applications in sensing systems. Herein we report a one-pot solvothermal synthesis of N-doped carbon quantum dots (NCQDs) and the synthesis of a series of NCQDs with different nitrogen contents. The as-prepared NCQDs were compared with carbon quantum dots (CQDs); the introduction of nitrogen atoms largely increased the quantum yield of NCQDs and highest emission efficiency is up to 36.3 %. The fluorescence enhancement may originate from more polyaromatic structures induced by incorporated nitrogen atoms and protonation of nitrogen atoms on dots. It was found that NCQDs can act as a multifunctional fluorescence sensing platform because they can be used to detect pH values, Ag(I), and Fe(III) in aqueous solution. The fluorescence intensity of NCQDs is inversely proportional to pH values across a broad range from 5.0 to 13.5, which indicates that NCQDs can be devised as an effective pH indicator. Selective detection of Ag(I) and Fe(III) was achieved based on their distinctive fluorescence influence because Ag(I) can significantly enhance the fluorescence whereas Fe(III) can greatly quench the fluorescence. The quantitative determination of Ag(I) can be accomplished with NCQDs by using the linear relationship between fluorescence intensity of NCQDs and concentration of Ag(I). The sensitive detection of H2O2 was developed by taking advantage of the distinct quenching ability of Fe(III) and Fe(II) toward the fluorescence of NCQDs. Cellular toxicity test showed NCQDs still retain low toxicity to cells despite the introduction of a great deal of nitrogen atoms. Moreover, bioimaging experiments demonstrated that NCQDs have stronger resistance to photobleaching than CQDs and more excellent fluorescence labeling performance. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Fluorescence Experiments with Quinine

    Science.gov (United States)

    O'Reilly, James E.

    1975-01-01

    Describes a series of experiments which illustrate the analytical capabilities of fluorescence, and outlines two straightforward analyses involving real analyses. These experiments are suitable for an undergraduate instrumental analysis course and require approximately six to seven hours of laboratory time. (MLH)

  18. FLEX: fluorescence explorer

    NARCIS (Netherlands)

    Stoll, M.Ph.; Court, A.J.; Smorenburg, C.; Visser, H.; Crocco, L.; Heilimo, J.; Honig, A.

    1999-01-01

    FLEX is a scientifically driven space mission to provide demonstration/validation of the instrumentation and technique for measuring the natural fluorescence of vegetation in the Fraunhofer lines. The payload consists of high spectral resolution (0.1-0.3 nm) CCD imaging grating spectrometer with two

  19. Atom probe crystallography

    National Research Council Canada - National Science Library

    Gault, Baptiste; Moody, Michael P; Cairney, Julie M; Ringer, Simon P

    2012-01-01

    This review addresses new developments in the emerging area of "atom probe crystallography", a materials characterization tool with the unique capacity to reveal both composition and crystallographic...

  20. Dephasing in an atom

    OpenAIRE

    2011-01-01

    When an atom in vacuum is near a surface of a dielectric the energy of a fluctuating electromagnetic field depends on a distance between them resulting, as known, in the force called van der Waals one. Besides this fluctuation phenomenon there is one associated with formation of a mean electric field which is equivalent to an order parameter. In this case atomic electrons are localized within atomic distances close to the atom and the total ground state energy is larger, compared to the bare ...

  1. Time-of-flight detection of ultra-cold atoms using resonant frequency modulation imaging.

    Science.gov (United States)

    Hardman, K S; Wigley, P B; Everitt, P J; Manju, P; Kuhn, C C N; Robins, N P

    2016-06-01

    Resonant frequency modulation imaging is used to detect free falling ultra-cold atoms. A theoretical comparison of fluorescence imaging (FI) and frequency modulation imaging (FMI) is made, indicating that for low optical depth clouds, FMI accomplished a higher signal-to-noise ratio under conditions necessary for a 200 μm spatially resolved atom interferometer. A 750 ms time-of-flight measurement reveals near atom shot-noise limited number measurements of 2×106 Bose-condensed Rb87 atoms. The detection system is applied to high precision spinor BEC based atom interferometer.

  2. NANODIAMONDS FOR FLUORESCENT CELL AND SENSOR NANOTECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    V. I. Nazarenko

    2013-10-01

    Full Text Available This review addresses the analysis of properties and applications of fluorescent nanodiamonds. They are carbon nanostructures with atomic arrangement of a diamond and carry all its properties, including record — high density, rigidity and refraction index. They are of almost spherical shape, and their small size (~4–10 nm creates substantial surface area that can be used for absorption of different compounds including drugs. Their surface is formed by different chemical groups (hydroxyls, carboxyls, etc. exhibits also chemical reactivity that allows different types of modifications. This opens innumerable possibilities for constructing different functional nanomaterials. The technologies have been developed for making these nanodiamonds fluorescent. Particularly, these properties are achieved by radioactive treatment with the formation of N–V impurities. These particles absorb and emit light in convenient for observation visible range of spectrum. They do not photobleach, which is very attractive for fluorescent microscopy of the cell. And, finally, these nanoparticles do not display toxicity on the cellular or whole — body level, and because of their biocompatibility they can be used in vivo as contrast agents and drug carriers. It is expected that future biotechnological applications of these nanoparticles will be connected with the creation of nanocomposites that combine multiple useful functions.

  3. Photon-correlation measurements of atomic-cloud temperature using an optical nanofiber

    CERN Document Server

    Grover, J A; Orozco, L A; Rolston, S L

    2015-01-01

    We develop a temperature measurement of an atomic cloud based on the temporal correlations of fluorescence photons evanescently coupled into an optical nanofiber. We measure the temporal width of the intensity-intensity correlation function due to atomic transit time and use it to determine the most probable atomic velocity, hence the temperature. This technique agrees well with standard time-of-flight temperature measurements. We confirm our results with trajectory simulations.

  4. Evanescent Wave Atomic Mirror

    Science.gov (United States)

    Ghezali, S.; Taleb, A.

    2008-09-01

    A research project at the "Laboratoire d'électronique quantique" consists in a theoretical study of the reflection and diffraction phenomena via an atomic mirror. This poster presents the principle of an atomic mirror. Many groups in the world have constructed this type of atom optics experiments such as in Paris-Orsay-Villetaneuse (France), Stanford-Gaithersburg (USA), Munich-Heidelberg (Germany), etc. A laser beam goes into a prism with an incidence bigger than the critical incidence. It undergoes a total reflection on the plane face of the prism and then exits. The transmitted resulting wave out of the prism is evanescent and repulsive as the frequency detuning of the laser beam compared to the atomic transition δ = ωL-ω0 is positive. The cold atomic sample interacts with this evanescent wave and undergoes one or more elastic bounces by passing into backward points in its trajectory because the atoms' kinetic energy (of the order of the μeV) is less than the maximum of the dipolar potential barrier ℏΩ2/Δ where Ω is the Rabi frequency [1]. In fact, the atoms are cooled and captured in a magneto-optical trap placed at a distance of the order of the cm above the prism surface. The dipolar potential with which interact the slow atoms is obtained for a two level atom in a case of a dipolar electric transition (D2 Rubidium transition at a wavelength of 780nm delivered by a Titane-Saphir laser between a fundamental state Jf = l/2 and an excited state Je = 3/2). This potential is corrected by an attractive Van der Waals term which varies as 1/z3 in the Lennard-Jones approximation (typical atomic distance of the order of λ0/2π where λ0 is the laser wavelength) and in 1/z4 if the distance between the atom and its image in the dielectric is big in front of λ0/2π. This last case is obtained in a quantum electrodynamic calculation by taking into account an orthornormal base [2]. We'll examine the role of spontaneous emission for which the rate is inversely

  5. Rydberg atom detection of the temporal coherence of cosmic microwave background radiation

    CERN Document Server

    Tscherbul, Timur V

    2013-01-01

    Rydberg atoms immersed in cold blackbody radiation are shown to display long-lived quantum coherence effects on timescales of tens of picoseconds. By solving non-Markovian equations of motion with no free parameters we obtain the time evolution of the density matrix, and demonstrate that the blackbody-induced temporal coherences manifest as quantum beats in time-resolved fluorescence intensities of the Rydberg atoms. A measurable fluorescence signal can be obtained with a cold trapped ensemble of 1e8 Rydberg atoms subject to 2.7 K cosmic microwave background radiation (CMB), allowing for novel insights into previously unexamined quantum coherence properties of CMB.

  6. Atomic transition probabilities of Er i

    Science.gov (United States)

    Lawler, J. E.; Wyart, J.-F.; Den Hartog, E. A.

    2010-12-01

    Atomic transition probabilities for 562 lines of the first spectrum of erbium (Er i) are reported. These data are from new branching fraction measurements on Fourier transform spectra normalized with previously reported radiative lifetimes from time-resolved laser-induced fluorescence measurements (Den Hartog et al 2010 J. Phys. B: At. Mol. Opt. Phys. 43 155004). The wavelength range of the data set is from 298 to 1981 nm. In this work we explore the utility of parametric fits based on the Cowan code in assessing branching fraction errors due to lines connecting to unobserved lower levels.

  7. Atomic transition probabilities of Gd i

    Science.gov (United States)

    Lawler, J. E.; Bilty, K. A.; Den Hartog, E. A.

    2011-05-01

    Fourier transform spectra are used to determine emission branching fractions for 1290 lines of the first spectrum of gadolinium (Gd i). These branching fractions are converted to absolute atomic transition probabilities using previously reported radiative lifetimes from time-resolved laser-induced-fluorescence measurements (Den Hartog et al 2011 J. Phys. B: At. Mol. Opt. Phys. 44 055001). The wavelength range of the data set is from 300 to 1850 nm. A least squares technique for separating blends of the first and second spectra lines is also described and demonstrated in this work.

  8. Atomic transition probabilities of Nd I

    Science.gov (United States)

    Stockett, M. H.; Wood, M. P.; Den Hartog, E. A.; Lawler, J. E.

    2011-12-01

    Fourier transform spectra are used to determine emission branching fractions for 236 lines of the first spectrum of neodymium (Nd i). These branching fractions are converted to absolute atomic transition probabilities using radiative lifetimes from time-resolved laser-induced fluorescence measurements (Den Hartog et al 2011 J. Phys. B: At. Mol. Opt. Phys. 44 225001). The wavelength range of the data set is from 390 to 950 nm. These transition probabilities from emission and laser measurements are compared to relative absorption measurements in order to assess the importance of unobserved infrared branches from selected upper levels.

  9. Sensitive spectroscopy of an ytterbium atomic beam

    CERN Document Server

    Guttridge, A; Kemp, S L; Boddy, D; Freytag, R; Tarbutt, M R; Hinds, E A; Cornish, S L

    2015-01-01

    Experimental studies of ultracold ytterbium atoms generally involve the frequency stabilisation (locking) of lasers to two transitions at 399 and 556 nm in order to implement laser cooling. Here we present a simple and robust apparatus for generation of suitable, narrow fluorescence signals with a high signal to noise ratio at both wavelengths. The design utilises easily acquired vacuum parts, optics and electronics and requires very little laser power. We demonstrate the stability and precision of the frequency stabilisation at 556 nm by presenting sensitive measurements of the gravitational sag of an ytterbium MOT as a function of laser power.

  10. Single molecule DNA detection with an atomic vapor notch filter

    Energy Technology Data Exchange (ETDEWEB)

    Uhland, Denis; Rendler, Torsten; Widmann, Matthias; Lee, Sang-Yun [University of Stuttgart and Stuttgart Research Center of Photonic Engineering (SCoPE) and IQST, 3rd Physics Institute, Stuttgart (Germany); Wrachtrup, Joerg; Gerhardt, Ilja [University of Stuttgart and Stuttgart Research Center of Photonic Engineering (SCoPE) and IQST, 3rd Physics Institute, Stuttgart (Germany); Max Planck Institute for Solid State Research, Stuttgart (Germany)

    2015-12-01

    The detection of single molecules has facilitated many advances in life- and material-science. Commonly the fluorescence of dye molecules is detected, which are attached to a non-fluorescent structure under study. For fluorescence microscopy one desires to maximize the detection efficiency together with an efficient suppression of undesired laser leakage. Here we present the use of the narrow-band filtering properties of hot atomic sodium vapor to selectively filter the excitation light from the red-shifted fluorescence of dye labeled single-stranded DNA molecules. A statistical analysis proves an enhancement in detection efficiency of more than 15% in a confocal and in a wide-field configuration. (orig.)

  11. Atomic Scale Plasmonic Switch.

    Science.gov (United States)

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Pedersen, Andreas; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2016-01-13

    The atom sets an ultimate scaling limit to Moore's law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocation of an individual or, at most, a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ratio of 9.2 dB and operation at room temperature up to MHz with femtojoule (fJ) power consumption for a single switch operation. This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspectives for a fully integrated and highly scalable chip platform, a platform where optics, electronics, and memory may be controlled at the single-atom level.

  12. Greek Atomic Theory.

    Science.gov (United States)

    Roller, Duane H. D.

    1981-01-01

    Focusing on history of physics, which began about 600 B.C. with the Ionian Greeks and reaching full development within three centuries, suggests that the creation of the concept of the atom is understandable within the context of Greek physical theory; so is the rejection of the atomic theory by the Greek physicists. (Author/SK)

  13. Atoms, Molecules, and Compounds

    CERN Document Server

    Manning, Phillip

    2007-01-01

    Explores the atoms that govern chemical processes. This book shows how the interactions between simple substances such as salt and water are crucial to life on Earth and how those interactions are predestined by the atoms that make up the molecules.

  14. When Atoms Want

    Science.gov (United States)

    Talanquer, Vicente

    2013-01-01

    Chemistry students and teachers often explain the chemical reactivity of atoms, molecules, and chemical substances in terms of purposes or needs (e.g., atoms want or need to gain, lose, or share electrons in order to become more stable). These teleological explanations seem to have pedagogical value as they help students understand and use…

  15. When Atoms Want

    Science.gov (United States)

    Talanquer, Vicente

    2013-01-01

    Chemistry students and teachers often explain the chemical reactivity of atoms, molecules, and chemical substances in terms of purposes or needs (e.g., atoms want or need to gain, lose, or share electrons in order to become more stable). These teleological explanations seem to have pedagogical value as they help students understand and use…

  16. Synthesis and Fluorescence Spectra of Triazolylcoumarin Fluorescent Dyes

    Institute of Scientific and Technical Information of China (English)

    PENG Xian-fu; LI Hong-qi

    2009-01-01

    Much attention is devoted to fluorescent dyes especially those with potential in versatile applications. Reactions under "click" conditions between nonfluorescent 3 - azidocoumarins and terminal alkynes produced 3 -(1, 2, 3- triazol- 1 - yl)cournarins, a novel type of fluorescent dyes with intense fluorescence. The structures of the new coumarins were characterized by 1H NMR, MS, and IR spectra. Fluorescence spectra measurement demonstrated excellent fluorescence performance of the triazolylcoumarins and this click reaction is a promising candidate for bioconjugation and bioimaging applications since both azide and alkynes are quite inert to biological systems.

  17. Fluorescence nanoscopy. Methods and applications

    OpenAIRE

    Requejo-Isidro, Jose

    2013-01-01

    Fluorescence nanoscopy refers to the experimental techniques and analytical methods used for fluorescence imaging at a resolution higher than conventional, diffraction-limited, microscopy. This review explains the concepts behind fluorescence nanoscopy and focuses on the latest and promising developments in acquisition techniques, labelling strategies to obtain highly detailed super-resolved images and in the quantitative methods to extract meaningful information from them.

  18. Coaxial airblast atomizers

    Science.gov (United States)

    Hardalupas, Y.; Whitelaw, J. H.

    1993-01-01

    An experimental investigation was performed to quantify the characteristics of the sprays of coaxial injectors with particular emphasis on those aspects relevant to the performance of rocket engines. Measurements for coaxial air blast atomizers were obtained using air to represent the gaseous stream and water to represent the liquid stream. A wide range of flow conditions were examined for sprays with and without swirl for gaseous streams. The parameters varied include Weber number, gas flow rate, liquid flow rate, swirl, and nozzle geometry. Measurements were made with a phase Doppler velocimeter. Major conclusions of the study focused upon droplet size as a function of Weber number, effect of gas flow rate on atomization and spray spread, effect of nozzle geometry on atomization and spread, effect of swirl on atomization, spread, jet recirculation and breakup, and secondary atomization.

  19. Theoretical atomic physics

    CERN Document Server

    Friedrich, Harald

    2017-01-01

    This expanded and updated well-established textbook contains an advanced presentation of quantum mechanics adapted to the requirements of modern atomic physics. It includes topics of current interest such as semiclassical theory, chaos, atom optics and Bose-Einstein condensation in atomic gases. In order to facilitate the consolidation of the material covered, various problems are included, together with complete solutions. The emphasis on theory enables the reader to appreciate the fundamental assumptions underlying standard theoretical constructs and to embark on independent research projects. The fourth edition of Theoretical Atomic Physics contains an updated treatment of the sections involving scattering theory and near-threshold phenomena manifest in the behaviour of cold atoms (and molecules). Special attention is given to the quantization of weakly bound states just below the continuum threshold and to low-energy scattering and quantum reflection just above. Particular emphasis is laid on the fundamen...

  20. Maximally Atomic Languages

    Directory of Open Access Journals (Sweden)

    Janusz Brzozowski

    2014-05-01

    Full Text Available The atoms of a regular language are non-empty intersections of complemented and uncomplemented quotients of the language. Tight upper bounds on the number of atoms of a language and on the quotient complexities of atoms are known. We introduce a new class of regular languages, called the maximally atomic languages, consisting of all languages meeting these bounds. We prove the following result: If L is a regular language of quotient complexity n and G is the subgroup of permutations in the transition semigroup T of the minimal DFA of L, then L is maximally atomic if and only if G is transitive on k-subsets of 1,...,n for 0 <= k <= n and T contains a transformation of rank n-1.

  1. Atomic diffusion in stars

    CERN Document Server

    Michaud, Georges; Richer, Jacques

    2015-01-01

    This book gives an overview of atomic diffusion, a fundamental physical process, as applied to all types of stars, from the main sequence to neutron stars. The superficial abundances of stars as well as their evolution can be significantly affected. The authors show where atomic diffusion plays an essential role and how it can be implemented in modelling.  In Part I, the authors describe the tools that are required to include atomic diffusion in models of stellar interiors and atmospheres. An important role is played by the gradient of partial radiative pressure, or radiative acceleration, which is usually neglected in stellar evolution. In Part II, the authors systematically review the contribution of atomic diffusion to each evolutionary step. The dominant effects of atomic diffusion are accompanied by more subtle effects on a large number of structural properties throughout evolution. One of the goals of this book is to provide the means for the astrophysicist or graduate student to evaluate the importanc...

  2. Control of light trapping in a large atomic system by a static magnetic field

    CERN Document Server

    Skipetrov, S E; Havey, M D

    2016-01-01

    We propose to control light trapping in a large ensemble of cold atoms by an external, static magnetic field. For an appropriate choice of frequency and polarization of the exciting pulse, the field is expected to speed up the fluorescence of a dilute atomic system but can significantly slow it down in a dense ensemble. The slowing down of fluorescence is due to the excitation of spatially localized collective atomic states that appear only under a strong magnetic field and have exponentially long lifetimes. The control of fluorescence by the magnetic field may be of interest for use in future quantum-information processing devices. It also paves a way towards the experimental observation of the disorder-induced localization of light in cold atomic systems.

  3. Fluorescent Thiol-Derivatized Gold Clusters Embedded in Polymers

    Directory of Open Access Journals (Sweden)

    G. Carotenuto

    2013-01-01

    Full Text Available Owing to aurophilic interactions, linear and/or planar Au(I-thiolate molecules spontaneously aggregate, leading to molecular gold clusters passivated by a thiolate monolayer coating. Differently from the thiolate precursors, such cluster compounds show very intensive visible fluorescence characteristics that can be tuned by alloying the gold clusters with silver atoms or by conjugating the electronic structure of the metallic core with unsaturated electronic structures in the organic ligand through the sulphur atom. Here, the photoluminescence features of some examples of these systems are shortly described.

  4. Functionalization of hydroxyl terminated polybutadiene with biologically active fluorescent molecule

    Indian Academy of Sciences (India)

    R Murali Sankar; Subhadeep Saha; K Seeni Meera; Tushar Jana

    2009-10-01

    A biologically active molecule, 2-chloro-4,6-bis(dimethylamino)-1,3,5-triazine (CBDT), has been covalently attached at the terminal carbon atoms of the hydroxyl terminated polybutadiene (HTPB) backbone. The modification of HTPB backbone by CBDT molecule does not affect the unique physico-chemical properties such as fluidity, hydroxyl value and microstructure of the parent HTPB. The formation of hydrogen bonding between the terminal hydroxyl groups and the nitrogen atoms of triazine moiety is the driving force for the terminal attachment chemistry. The functionalized HTPB (HTPB–CBDT) shows a strong fluorescence emission at 385 nm.

  5. Characterization of a velocity-tunable 87Rb cold atomic source with a high-speed imaging technology

    Institute of Scientific and Technical Information of China (English)

    Feng Yan-Ying; Zhu Chang-Xing; Wang Xiao-Jia; Xue Hong-Bo; Ye Xiong-Ying; Zhou Zhao-Ying

    2009-01-01

    This paper has developed and characterized a method to produce a velocity-tunable 87Rb cold atomic source for atomic interferometry application.Using a high speed fluorescence imaging technology,it reports that the dynamic process of the atomic source formation is observed and the source performances including the flux and the initial velocity axe characterized.A tunable atomic source with the initial velocity of 1.4~2.6 m/s and the atomic source flux of 2×108~6×109 atoms/s has been obtained with the built experimental setup.

  6. Two photon dissociation of benzene, phenylacetylene, and benzaldehyde at 243 nm: translational energy releases in the H atom channel

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Seung Keun; Kim, Hong Lae [Kangwon National Univ., Chuncheon (Korea, Republic of); Park, Chan Ryang [Kookmin Univ., Seoul (Korea, Republic of)

    2002-02-01

    Hydrogen atom production channels from photodissociation of benzene, phenylacetylene, and benzaldehyde at 243 nm have been investigated by detecting H atoms using two photon absorption at 243.2 nm and induced fluorescence at 121.6 nm. Translational energies of the H atoms were measured by Doppler broadened H atom spectra. By absorption of two photons at 243 nm, the H atoms are statistically produced from benzene and phenylacetylene whereas the H atoms from the aldehyde group in benzaldehyde are produced from different pathways. The possible dissociation mechanisms are discussed from the measured translational energy releases.

  7. Delayed fluorescence in photosynthesis.

    Science.gov (United States)

    Goltsev, Vasilij; Zaharieva, Ivelina; Chernev, Petko; Strasser, Reto J

    2009-01-01

    Photosynthesis is a very efficient photochemical process. Nevertheless, plants emit some of the absorbed energy as light quanta. This luminescence is emitted, predominantly, by excited chlorophyll a molecules in the light-harvesting antenna, associated with Photosystem II (PS II) reaction centers. The emission that occurs before the utilization of the excitation energy in the primary photochemical reaction is called prompt fluorescence. Light emission can also be observed from repopulated excited chlorophylls as a result of recombination of the charge pairs. In this case, some time-dependent redox reactions occur before the excitation of the chlorophyll. This delays the light emission and provides the name for this phenomenon-delayed fluorescence (DF), or delayed light emission (DLE). The DF intensity is a decreasing polyphasic function of the time after illumination, which reflects the kinetics of electron transport reactions both on the (electron) donor and the (electron) acceptor sides of PS II. Two main experimental approaches are used for DF measurements: (a) recording of the DF decay in the dark after a single turnover flash or after continuous light excitation and (b) recording of the DF intensity during light adaptation of the photosynthesizing samples (induction curves), following a period of darkness. In this paper we review historical data on DF research and recent advances in the understanding of the relation between the delayed fluorescence and specific reactions in PS II. An experimental method for simultaneous recording of the induction transients of prompt and delayed chlorophyll fluorescence and decay curves of DF in the millisecond time domain is discussed.

  8. 78 FR 58571 - Maine Yankee Atomic Power Company, Connecticut Yankee Atomic Power Company, and The Yankee Atomic...

    Science.gov (United States)

    2013-09-24

    ... Atomic Power Company, Connecticut Yankee Atomic Power Company, and The Yankee Atomic Electric Company... Power Company (Maine Yankee), Connecticut Yankee Atomic Power Company (Connecticut Yankee), and the Yankee Atomic Electric Company (Yankee Atomic) (together, ``licensees'' or ``the Yankee Companies'')...

  9. Linear atomic quantum coupler

    CERN Document Server

    El-Orany, Faisal A A

    2009-01-01

    In this paper, we develop the notion of the linear atomic quantum coupler. This device consists of two modes propagating into two waveguides, each of them includes a localized and/or a trapped atom. These waveguides are placed close enough to allow exchanging energy between them via evanescent waves. Each mode interacts with the atom in the same waveguide in the standard way, i.e. as the Jaynes-Cummings model (JCM), and with the atom-mode in the second waveguide via evanescent wave. We present the Hamiltonian for the system and deduce the exact form for the wavefunction. We investigate the atomic inversions and the second-order correlation function. In contrast to the conventional linear coupler, the atomic quantum coupler is able to generate nonclassical effects. The atomic inversions can exhibit long revival-collapse phenomenon as well as subsidiary revivals based on the competition among the switching mechanisms in the system. Finally, under certain conditions, the system can yield the results of the two-m...

  10. Atomic Structure Theory Lectures on Atomic Physics

    CERN Document Server

    Johnson, Walter R

    2007-01-01

    Atomic Structure Theory is a textbook for students with a background in quantum mechanics. The text is designed to give hands-on experience with atomic structure calculations. Material covered includes angular momentum methods, the central field Schrödinger and Dirac equations, Hartree-Fock and Dirac-Hartree-Fock equations, multiplet structure, hyperfine structure, the isotope shift, dipole and multipole transitions, basic many-body perturbation theory, configuration interaction, and correlation corrections to matrix elements. Numerical methods for solving the Schrödinger and Dirac eigenvalue problems and the (Dirac)-Hartree-Fock equations are given as well. B-spline basis sets are used to carry out sums arising in higher-order many-body calculations. Illustrative problems are provided, together with solutions. FORTRAN programs implementing the numerical methods in the text are included.

  11. Inside the Hydrogen Atom

    CERN Document Server

    Nowakowski, M; Fierro, D Bedoya; Manjarres, A D Bermudez

    2016-01-01

    We apply the non-linear Euler-Heisenberg theory to calculate the electric field inside the hydrogen atom. We will demonstrate that the electric field calculated in the Euler-Heisenberg theory can be much smaller than the corresponding field emerging from the Maxwellian theory. In the hydrogen atom this happens only at very small distances. This effect reduces the large electric field inside the hydrogen atom calculated from the electromagnetic form-factors via the Maxwell equations. The energy content of the field is below the pair production threshold.

  12. Atom trap trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O' Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  13. Atom probe tomography today

    Directory of Open Access Journals (Sweden)

    Alfred Cerezo

    2007-12-01

    Full Text Available This review aims to describe and illustrate the advances in the application of atom probe tomography that have been made possible by recent developments, particularly in specimen preparation techniques (using dual-beam focused-ion beam instruments but also of the more routine use of laser pulsing. The combination of these two developments now permits atomic-scale investigation of site-specific regions within engineering alloys (e.g. at grain boundaries and in the vicinity of cracks and also the atomic-level characterization of interfaces in multilayers, oxide films, and semiconductor materials and devices.

  14. Physics of the atom

    CERN Document Server

    Wehr, Russell M; Adair, Thomas W

    1984-01-01

    The fourth edition of Physics of the Atom is designed to meet the modern need for a better understanding of the atomic age. It is an introduction suitable for students with a background in university physics and mathematical competence at the level of calculus. This book is designed to be an extension of the introductory university physics course into the realm of atomic physics. It should give students a proficiency in this field comparable to their proficiency in mechanics, heat, sound, light, and electricity.

  15. Rydberg atoms in astrophysics

    CERN Document Server

    Gnedin, Yu N; Ignjatovic, Lj M; Sakan, N M; Sreckovic, V A; Zakharov, M Yu; Bezuglov, N N; Klycharev, A N; 10.1016/j.newar.2009.07.003

    2012-01-01

    Elementary processes in astrophysical phenomena traditionally attract researchers attention. At first this can be attributed to a group of hemi-ionization processes in Rydberg atom collisions with ground state parent atoms. This processes might be studied as a prototype of the elementary process of the radiation energy transformation into electrical one. The studies of nonlinear mechanics have shown that so called regime of dynamic chaos should be considered as typical, rather than exceptional situation in Rydberg atoms collision. From comparison of theory with experimental results it follows that a such kind of stochastic dynamic processes, occurred during the single collision, may be observed.

  16. Atomic entanglement and decoherence

    Science.gov (United States)

    Genes, Claudiu

    The generation of entanglement in atomic systems plays a central topic in the fields of quantum information storage and processing. Moreover, a special category of entangled states of multi-atom ensembles, spin squeezed states, have been proven to lead to considerable improvement in the sensitivity of precision measurements compared to systems involving uncorrelated atoms. A treatment of entanglement in open systems is, however, incomplete without a precise description of the process of decoherence which necessarily accompanies it. The theory of entanglement and decoherence are the two main topics of this thesis. Methods are described for the generation of strong correlations in large atomic ensembles using either cavity quantum electrodynamics or measurement outcome conditioned quantum dynamics. Moreover, the description of loss of entanglement resulting from the coupling to a noise reservoir (electromagnetic vacuum) is explored. A spin squeezing parameter is used throughout this thesis as both a measure of entanglement strength and as an indication of the sensitivity improvement above the so-called standard quantum limit (sensitivity obtained with uncorrelated particles) in metrology. The first scheme considered consists of a single mode cavity field interacting with a collection of atoms for which spin squeezing is produced in both resonant and off-resonant regimes. In the resonant case, transfer of squeezing from a field state to the atoms is analyzed, while in the off-resonant regime squeezing is produced via an effective nonlinear interaction (one-axis twisting Hamiltonian). A second, more experimentally realistic case, is one involving the interaction of free space atoms with laser pulses; a projective measurement of a source field originating from atomic fluctuations provides a means of preparing atomic collective states such as spin squeezed and Schrodinger cat states. A new "unravelling" is proposed, that employs the detection of photon number in a single

  17. Atomic and molecular supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.

    1997-12-01

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra lead to strong constraints on the supernova explosion models.

  18. EINSTEIN, SCHROEDINGER, AND ATOM

    Directory of Open Access Journals (Sweden)

    Trunev A. P.

    2014-03-01

    Full Text Available In this paper, we consider gravitation theory in multidimensional space. The model of the metric satisfying the basic requirements of quantum theory is proposed. It is shown that gravitational waves are described by the Liouville equation and the Schrodinger equation as well. The solutions of the Einstein equations describing the stationary states of arbitrary quantum and classical systems with central symmetry have been obtained. Einstein’s atom model has been developed, and proved that atoms and atomic nuclei can be represented as standing gravitational waves

  19. Single-atom nanoelectronics

    CERN Document Server

    Prati, Enrico

    2013-01-01

    Single-Atom Nanoelectronics covers the fabrication of single-atom devices and related technology, as well as the relevant electronic equipment and the intriguing new phenomena related to single-atom and single-electron effects in quantum devices. It also covers the alternative approaches related to both silicon- and carbon-based technologies, also from the point of view of large-scale industrial production. The publication provides a comprehensive picture of the state of the art at the cutting edge and constitutes a milestone in the emerging field of beyond-CMOS technology. Although there are

  20. History of early atomic clocks

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, N.F. [Harvard Univ., Cambridge, MA (United States). Lyman Lab. of Physics

    2005-06-01

    This review of the history of early atomic clocks includes early atomic beam magnetic resonance, methods of separated and successive oscillatory fields, microwave absorption, optical pumping and atomic masers. (author)

  1. Fluorescence characteristics of polychlorinated biphenyl isomers in cyclodextrin media

    Energy Technology Data Exchange (ETDEWEB)

    Femia, R.A.; Scypinski, S.; Love, L.J.C.

    1985-01-01

    The fluorescence characteristics of several polychlorinated biphenyl (PCB) isomers in ..cap alpha..- and ..beta..-cyclodextrin (CD) are discussed and contrasted. The steric hindrance of PCBs imposed by the positions of the chlorine atoms on the rings determines the overall stability of the resulting inclusion complexes with cyclodextrin which is reflected in the fluorescence intensities. Less substituted homologues include into the CD cavity equally well in both cyclodextrins, but very heavily substituted molecules show drastic differences between their fluorescence intensities in the ..cap alpha..- and ..beta..-cyclodextrin solutions. This behavior can be employed as a method for spectral fractionation of PCB isomers. Spectral separation is demonstrated here for two variably substituted molecules, and the photophysical limitations of this approach are discussed.

  2. BIOCOMPATIBLE FLUORESCENT MICROSPHERES: SAFE PARTICLES FOR MATERIAL PENETRATION STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Farquar, G; Leif, R

    2009-07-15

    Biocompatible polymers with hydrolyzable chemical bonds have been used to produce safe, non-toxic fluorescent microspheres for material penetration studies. The selection of polymeric materials depends on both biocompatibility and processability, with tailored fluorescent properties depending on specific applications. Microspheres are composed of USFDA-approved biodegradable polymers and non-toxic fluorophores and are therefore suitable for tests where human exposure is possible. Micropheres were produced which contain unique fluorophores to enable discrimination from background aerosol particles. Characteristics that affect dispersion and adhesion can be modified depending on use. Several different microsphere preparation methods are possible, including the use of a vibrating orifice aerosol generator (VOAG), a Sono-Tek atomizer, an emulsion technique, and inkjet printhead. Applications for the fluorescent microspheres include challenges for biodefense system testing, calibrants for biofluorescence sensors, and particles for air dispersion model validation studies.

  3. Atomical Grothendieck categories

    Directory of Open Access Journals (Sweden)

    C. Năstăsescu

    2003-01-01

    Full Text Available Motivated by the study of Gabriel dimension of a Grothendieck category, we introduce the concept of atomical Grothendieck category, which has only two localizing subcategories, and we give a classification of this type of Grothendieck categories.

  4. Atomic bomb health benefits.

    Science.gov (United States)

    Luckey, T D

    2008-01-01

    Media reports of deaths and devastation produced by atomic bombs convinced people around the world that all ionizing radiation is harmful. This concentrated attention on fear of miniscule doses of radiation. Soon the linear no threshold (LNT) paradigm was converted into laws. Scientifically valid information about the health benefits from low dose irradiation was ignored. Here are studies which show increased health in Japanese survivors of atomic bombs. Parameters include decreased mutation, leukemia and solid tissue cancer mortality rates, and increased average lifespan. Each study exhibits a threshold that repudiates the LNT dogma. The average threshold for acute exposures to atomic bombs is about 100 cSv. Conclusions from these studies of atomic bomb survivors are: One burst of low dose irradiation elicits a lifetime of improved health.Improved health from low dose irradiation negates the LNT paradigm.Effective triage should include radiation hormesis for survivor treatment.

  5. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1998-01-01

    This volume continues the series'' cutting-edge reviews on developments in this field. Since its invention in the 1920s, electrostatic precipitation has been extensively used in industrial hygiene to remove dust and particulate matter from gases before entering the atmosphere. This combination of electrostatic precipitation is reported upon in the first chapter. Following this, chapter two reviews recent advances in the area of chemical modification in electrothermal atomization. Chapter three consists of a review which deal with advances and uses of electrothermal atomization atomic absorption spectrometry. Flow injection atomic spectroscopy has developed rapidly in recent years and after a general introduction, various aspects of this technique are looked at in chapter four. Finally, in chapter five the use of various spectrometric techniques for the determination of mercury are described.

  6. Atom chip gravimeter

    Science.gov (United States)

    Schubert, Christian; Abend, Sven; Gebbe, Martina; Gersemann, Matthias; Ahlers, Holger; Müntinga, Hauke; Matthias, Jonas; Sahelgozin, Maral; Herr, Waldemar; Lämmerzahl, Claus; Ertmer, Wolfgang; Rasel, Ernst

    2016-04-01

    Atom interferometry has developed into a tool for measuring rotations [1], accelerations [2], and testing fundamental physics [3]. Gravimeters based on laser cooled atoms demonstrated residual uncertainties of few microgal [2,4] and were simplified for field applications [5]. Atomic gravimeters rely on the interference of matter waves which are coherently manipulated by laser light fields. The latter can be interpreted as rulers to which the position of the atoms is compared. At three points in time separated by a free evolution, the light fields are pulsed onto the atoms. First, a coherent superposition of two momentum states is produced, then the momentum is inverted, and finally the two trajectories are recombined. Depending on the acceleration the atoms experienced, the number of atoms detected in the output ports will change. Consequently, the acceleration can be determined from the output signal. The laser cooled atoms with microkelvin temperatures used in state-of-the-art gravimeters impose limits on the accuracy [4]. Therefore, ultra-cold atoms generated by Bose-Einstein condensation and delta-kick collimation [6,7] are expected to be the key for further improvements. These sources suffered from a low flux implying an incompatible noise floor, but a competitive performance was demonstrated recently with atom chips [8]. In the compact and robust setup constructed for operation in the drop tower [6] we demonstrated all steps necessary for an atom chip gravimeter with Bose-Einstein condensates in a ground based operation. We will discuss the principle of operation, the current performance, and the perspectives to supersede the state of the art. The authors thank the QUANTUS cooperation for contributions to the drop tower project in the earlier stages. This work is supported by the German Space Agency (DLR) with funds provided by the Federal Ministry for Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under grant numbers DLR 50WM

  7. Zeeman atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hadeishi, T.; McLaughlin, R.

    1978-08-01

    The design and development of a Zeeman atomic absorption spectrometer for trace element analysis are described. An instruction manual is included which details the operation, adjustment, and maintenance. Specifications and circuit diagrams are given. (WHK)

  8. Topics in atomic physics

    CERN Document Server

    Burkhardt, Charles E

    2006-01-01

    The study of atomic physics propelled us into the quantum age in the early twentieth century and carried us into the twenty-first century with a wealth of new and, in some cases, unexplained phenomena. Topics in Atomic Physics provides a foundation for students to begin research in modern atomic physics. It can also serve as a reference because it contains material that is not easily located in other sources. A distinguishing feature is the thorough exposition of the quantum mechanical hydrogen atom using both the traditional formulation and an alternative treatment not usually found in textbooks. The alternative treatment exploits the preeminent nature of the pure Coulomb potential and places the Lenz vector operator on an equal footing with other operators corresponding to classically conserved quantities. A number of difficult to find proofs and derivations are included as is development of operator formalism that permits facile solution of the Stark effect in hydrogen. Discussion of the classical hydrogen...

  9. Atomic & Molecular Interactions

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-07-12

    The Gordon Research Conference (GRC) on Atomic & Molecular Interactions was held at Roger Williams University, Bristol, RI. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  10. Atomic Interferometry Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Vertical cavity surface emitting lasers (VCSELs) is a new technology which can be used for developing high performance laser components for atom-based sensors...

  11. Two-dimensional atom localization induced by a squeezed vacuum

    Science.gov (United States)

    Wang, Fei; Xu, Jun

    2016-10-01

    A scheme of two-dimensional (2D) atom localization induced by a squeezed vacuum is proposed, in which the three-level V-type atoms interact with two classical standing-wave fields. It is found that when the environment is changed from an ordinary vacuum to a squeezed vacuum, the 2D atom localization is realized by detecting the position-dependent resonance fluorescence spectrum. For comparison, we demonstrate that the atom localization originating from the quantum interference effect is distinct from that induced by a squeezed vacuum. Furthermore, the combined effects of the squeezed vacuum and quantum interference are also discussed under appropriate conditions. The internal physical mechanism is analyzed in terms of dressed-state representation. Project supported by the National Natural Science Foundation of China (Grant Nos. 11574179 and 11204099) and the Natural Science Foundation of Hubei Province, China (Grant No. 2014CFC1148).

  12. Super-resolution microscopy of single atoms in optical lattices

    CERN Document Server

    Alberti, Andrea; Alt, Wolfgang; Brakhane, Stefan; Karski, Michał; Reimann, René; Widera, Artur; Meschede, Dieter

    2015-01-01

    We report on image processing techniques and experimental procedures to determine the lattice-site positions of single atoms in an optical lattice with high reliability, even for limited acquisition time or optical resolution. Determining the positions of atoms beyond the diffraction limit relies on parametric deconvolution in close analogy to methods employed in super-resolution microscopy. We develop a deconvolution method that makes effective use of the prior knowledge of the optical transfer function, noise properties, and discreteness of the optical lattice. We show that accurate knowledge of the image formation process enables a dramatic improvement on the localization reliability. This is especially relevant for closely packed ensembles of atoms where the separation between particles cannot be directly optically resolved. Furthermore, we demonstrate experimental methods to precisely reconstruct the point spread function with sub-pixel resolution from fluorescence images of single atoms, and we give a m...

  13. Atom probe tomography today

    OpenAIRE

    Alfred Cerezo; Peter H. Clifton; Mark J. Galtrey; Humphreys, Colin J.; Kelly, Thomas. F.; David J. Larson; Sergio Lozano-Perez; Marquis, Emmanuelle A.; Oliver, Rachel A.; Gang Sha; Keith Thompson; Mathijs Zandbergen; Roger L. Alvis

    2007-01-01

    This review aims to describe and illustrate the advances in the application of atom probe tomography that have been made possible by recent developments, particularly in specimen preparation techniques (using dual-beam focused-ion beam instruments) but also of the more routine use of laser pulsing. The combination of these two developments now permits atomic-scale investigation of site-specific regions within engineering alloys (e.g. at grain boundaries and in the vicinity of cracks) and also...

  14. Metal atomization spray nozzle

    Science.gov (United States)

    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.

  15. Optical atomic magnetometer

    Science.gov (United States)

    Budker, Dmitry; Higbie, James; Corsini, Eric P

    2013-11-19

    An optical atomic magnetometers is provided operating on the principles of nonlinear magneto-optical rotation. An atomic vapor is optically pumped using linearly polarized modulated light. The vapor is then probed using a non-modulated linearly polarized light beam. The resulting modulation in polarization angle of the probe light is detected and used in a feedback loop to induce self-oscillation at the resonant frequency.

  16. Hirshfeld atom refinement.

    Science.gov (United States)

    Capelli, Silvia C; Bürgi, Hans-Beat; Dittrich, Birger; Grabowsky, Simon; Jayatilaka, Dylan

    2014-09-01

    Hirshfeld atom refinement (HAR) is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly-l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree-Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs) are freely refined without constraints or restraints - even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu's), all other structural parameters agree within less than 2 csu's. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules), the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å(2) as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements - an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å.

  17. Atoms, molecules & elements

    CERN Document Server

    Graybill, George

    2007-01-01

    Young scientists will be thrilled to explore the invisible world of atoms, molecules and elements. Our resource provides ready-to-use information and activities for remedial students using simplified language and vocabulary. Students will label each part of the atom, learn what compounds are, and explore the patterns in the periodic table of elements to find calcium (Ca), chlorine (Cl), and helium (He) through hands-on activities.

  18. Cavity enhanced atomic magnetometry

    OpenAIRE

    Herbert Crepaz; Li Yuan Ley; Rainer Dumke

    2015-01-01

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage...

  19. Correlative atomic force microscopy and localization-based super-resolution microscopy: revealing labelling and image reconstruction artefacts.

    Science.gov (United States)

    Monserrate, Aitor; Casado, Santiago; Flors, Cristina

    2014-03-17

    Hybrid microscopy: A correlative microscopy tool that combines in situ super-resolution fluorescence microscopy based on single-molecule localization and atomic force microscopy is presented. Direct comparison with high- resolution topography allows the authors to improve fluorescence labeling and image analysis in super-resolution imaging.

  20. MATERIALS WITH COMPLEX ELECTRONIC/ATOMIC STRUCTURES

    Energy Technology Data Exchange (ETDEWEB)

    D. M. PARKIN; L. CHEN; ET AL

    2000-09-01

    We explored both experimentally and theoretically the behavior of materials at stresses close to their theoretical strength. This involves the preparation of ultra fine scale structures by a variety of fabrication methods. In the past year work has concentrated on wire drawing of in situ composites such as Cu-Ag and Cu-Nb. Materials were also fabricated by melting alloys in glass and drawing them into filaments at high temperatures by a method known as Taylor wire technique. Cu-Ag microwires have been drawn by this technique to produce wires 10 {micro}m in diameter that consist of nanoscale grains of supersaturated solid solution. Organogels formed from novel organic gelators containing cholesterol tethered to squaraine dyes or trans-stilbene derivatives have been studied from several different perspectives. The two types of molecules are active toward several organic liquids, gelling in some cases at w/w percentages as low as 0.1. While relatively robust, acroscopically dry gels are formed in several cases, studies with a variety of probes indicate that much of the solvent may exist in domains that are essentially liquid-like in terms of their microenvironment. The gels have been imaged by atomic force microscopy and conventional and fluorescence microscopy, monitoring both the gelator fluorescence in the case of the stilbene-cholesterol gels and, the fluorescence of solutes dissolved in the solvent. Remarkably, our findings show that several of the gels are composed of similarly appearing fibrous structures visible at the nano-, micro-, and macroscale.

  1. The TALE Fluorescence Detectors

    Science.gov (United States)

    Jui, Charles

    2009-05-01

    The TALE fluorescence detectors are designed to extend the threshold for fluorescence observation by TA down to 3x10^16 eV. It will comprise two main components. The first is a set of 24 telescopes working in stereo, with an existing TA FD station at ˜6 km separation. These will cover between 3-31 degrees in elevation and have azimuthal coverage maximizing the stereo aperture in the 10^18-10^19 eV energy range. The second component consists of 15 telescopes equipped with 4m diameter mirrors and covering the sky between 31 and 73 degrees in elevation. The larger mirror size pushes the physics threshold down to 3x10^16 eV, and provides view of the shower maximum for the lower energy events. The Tower detector will cover one quadrant in azimuth and operate in hybrid mode with the TALE infill array to provide redundant composition measurements from both shower maximum information and muon-to-electron ratio.

  2. Effective potentials for atom-atom interaction at low temperatures

    OpenAIRE

    Gao, Bo

    2002-01-01

    We discuss the concept and design of effective atom-atom potentials that accurately describe any physical processes involving only states around the threshold. The existence of such potentials gives hope to a quantitative, and systematic, understanding of quantum few-atom and quantum many-atom systems at relatively low temperatures.

  3. A fluorescence scanning electron microscope

    Directory of Open Access Journals (Sweden)

    Takaaki Kanemaru

    2010-01-01

    Full Text Available Fluorescence techniques are widely used in biological research to examine molecular localization, while electron microscopy can provide unique ultrastructural information. To date, correlative images from both fluorescence and electron microscopy have been obtained separately using two different instruments, i.e. a fluorescence microscope (FM and an electron microscope (EM. In the current study, a scanning electron microscope (SEM (JEOL JXA8600 M was combined with a fluorescence digital camera microscope unit and this hybrid instrument was named a fluorescence SEM (FL-SEM. In the labeling of FL-SEM samples, both Fluolid, which is an organic EL dye, and Alexa Fluor, were employed. We successfully demonstrated that the FL-SEM is a simple and practical tool for correlative fluorescence and electron microscopy.

  4. Teleportation of Atomic States for Atoms in a Lambda Configuration

    CERN Document Server

    Guerra, E S

    2004-01-01

    In this article we discuss a scheme of teleportation of atomic states making use of three-level lambda atoms. The experimental realization proposed makes use of cavity QED involving the interaction of Rydberg atoms with a micromaser cavity prepared in a coherent state. We start presenting a scheme to prepare atomic EPR states involving two-level atoms via the interaction of these atoms with a cavity. In our scheme the cavity and some atoms play the role of auxiliary systems used to achieve the teleportation.

  5. High-precision metrology of highly charged ions via relativistic resonance fluorescence.

    Science.gov (United States)

    Postavaru, O; Harman, Z; Keitel, C H

    2011-01-21

    Resonance fluorescence of laser-driven highly charged ions is investigated with regard to precisely measuring atomic properties. For this purpose an ab initio approach based on the Dirac equation is employed that allows for studying relativistic ions. These systems provide a sensitive means to test correlated relativistic dynamics, quantum electrodynamic phenomena and nuclear effects by applying x-ray lasers. We show how the narrowing of sidebands in the x-ray fluorescence spectrum by interference due to an additional optical driving can be exploited to determine atomic dipole or multipole moments to unprecedented accuracy.

  6. Containerless study of metal evaporation by laser induced fluorescence

    Science.gov (United States)

    Schiffman, Robert A.; Nordine, Paul C.

    1987-01-01

    Laser induced fluorescence (LIF) detection of atomic vapors was used to study evaporation from electromagnetically levitated and CW CO2 laser-heated molybdenum spheres and resistively-heated tungsten filaments. Electromagnetic (EM) levitation in combination with laser heating of tungsten, zirconium, and aluminum specimens was also investigated. LIF intensity vs temperature data were obtained for molybdenum atoms and six electronic states of atomic tungsten, at temperatures up to the melting point of each metal. The detected fraction of the emitted radiation was reduced by self-absorption effects at the higher experimental temperatures. Vaporization enthalpies derived from data for which less than half the LIF intensity was self-absorbed were -636 + or - 24 kJ/g-mol for Mo and 831 + or - 32 kJ/g-mol for W. Space-based applications of EM levitation in combination with radiative heating are discussed.

  7. Fluorescence of ceramic color standards.

    Science.gov (United States)

    Koo, Annette; Clare, John F; Nield, Kathryn M; Deadman, Andrew; Usadi, Eric

    2010-04-20

    Fluorescence has been found in color standards available for use in calibration and verification of color measuring instruments. The fluorescence is excited at wavelengths below about 600?nm and emitted above 700?nm, within the response range of silicon photodiodes, but at the edge of the response of most photomultipliers and outside the range commonly scanned in commercial colorimeters. The degree of fluorescence on two of a set of 12 glossy ceramic tiles is enough to introduce significant error when those tiles have been calibrated in one mode of measurement and are used in another. We report the nature of the fluorescence and the implications for color measurement.

  8. Universal bosonic tetramers of dimer-atom-atom structure

    OpenAIRE

    Deltuva, A.

    2012-01-01

    Unstable four-boson states having an approximate dimer-atom-atom structure are studied using momentum-space integral equations for the four-particle transition operators. For a given Efimov trimer the universal properties of the lowest associated tetramer are determined. The impact of this tetramer on the atom-trimer and dimer-dimer collisions is analyzed. The reliability of the three-body dimer-atom-atom model is studied.

  9. Single-atom spintronics

    Institute of Scientific and Technical Information of China (English)

    Susan Z. HUA; Matthew R. SULLIVAN; Jason N. ARMSTRONG

    2006-01-01

    Recent work on magnetic quantum point contacts (QPCs) was discussed. Complete magnetoresistance loops across Co QPCs as small as a single atom was measured. The remarkable feature of these QPCs is the rapid oscillatory decay in magnetoresistance with the increase of contact size. In addition,stepwise or quantum magnetoresistance loops are observed,resulting from varying transmission probability of the available discrete conductance channels because the sample is cycled between the ferromagnetic (F) and antiferromagnetic (AF) aligned states. Quantized conductance combined with spin dependent transmission of electron waves gives rise to a multi-channel system with a quantum domain wall acting as a valve,i.e.,a quantum spin-valve. Behavior of a few-atom QPC is built on the behavior of a single-atom QPC and hence the summarization of results as 'single-atom spintronics'. An evolutionary trace of spin-dependent electron transmission from a single atom to bulk is provided,the requisite hallmarks of artefact-free magnetoresistance is established across a QPC - stepwise or quantum magnetoresistance loops and size dependent oscillatory magnetoresistance.

  10. Quantum magnetism through atomic assembly

    NARCIS (Netherlands)

    Spinelli, A.

    2015-01-01

    This thesis presents an experimental study of magnetic structures, composed of only a few atoms. Those structures are first built atom-by-atom and then locally probed, both with a low-temperature STM. The technique that we use to assemble them is vertical atom manipulation, while to study their phy

  11. Atom trap trace analysis of {sup 39}Ar

    Energy Technology Data Exchange (ETDEWEB)

    Welte, Joachim

    2011-12-14

    Detection of {sup 39}Ar in natural water samples can be employed for radiometric dating on a timescale of 50 to 1000 years before present. This experimental work comprises the setup of an atomic beam and trap apparatus that captures and detects {sup 39}Ar atoms by the laser-cooling technique ''Atom Trap Trace Analysis''. With this approach, the limitations of low-level counting, regarding sample size and measurement time, could be overcome. In the course of this work, the hyperfine structure spectrum of the cooling transition 1s{sub 5}-2p{sub 9} has been experimentally determined. A high intensity, optically collimated beam of slow metastable argon atoms has been set up and fluorescence detection of individual {sup 39}Ar atoms in a magneto-optical trap is realized. {sup 39}Ar count rates of 1 atom in about 4 hours have been achieved for atmospheric argon. Recent improvements further suggest that even higher count rates of 1 atom/hour are within reach.

  12. Fluorescence dynamics of green fluorescent protein in AOT reversed micelles

    NARCIS (Netherlands)

    Uskova, M.A.; Borst, J.W.; Hink, M.A.; Hoek, van A.; Schots, A.; Klyachko, N.L.; Visser, A.J.W.G.

    2000-01-01

    We have used the enhanced green fluorescent protein (EGFP) to investigate the properties of surfactant-entrapped water pools in organic solvents (reversed micelles) with steady-state and time-resolved fluorescence methods. The surfactant used was sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and the

  13. DNA Duplex Engineering for Enantioselective Fluorescent Sensor.

    Science.gov (United States)

    Hu, Yuehua; Lin, Fan; Wu, Tao; Zhou, Yufeng; Li, Qiusha; Shao, Yong; Xu, Zhiai

    2017-02-21

    The rapid identification of biomacromolecule structure that has a specific association with chiral enantiomers especially from natural sources will be helpful in developing enantioselective sensor and in speeding up drug exploitation. Herein, owing to its existence also in living cells, apurinic/apyrimidinic site (AP site) was first engineered into ds-DNA duplex to explore its competence in enantiomer selectivity. An AP site-specific fluorophore was utilized as an enantioselective discrimination probe to develop a straightforward chiral sensor using natural tetrahydropalmatine (L- and D-THP) as enantiomer representatives. We found that only L-THP can efficiently replace the prebound fluorophore to cause a significant fluorescence increase due to its specific binding with the AP site (two orders magnitude higher in affinity than binding with D-THP). The AP site binding specificity of L-THP over D-THP was assessed via intrinsic fluorescence, isothermal titration calorimetry, and DNA stability. The enantioselective performance can be easily tuned by the sequences near the AP site and the number of AP sites. A single AP site provides a perfect binding pocket to differentiate the chiral atom-induced structure discrepancy. We expect that our work will inspire interest in engineering local structures into a ds-DNA duplex for developing novel enantioselective sensors.

  14. Non-radiative excitation fluorescence microscopy

    Science.gov (United States)

    Riachy, Lina; Vézy, Cyrille; Jaffiol, Rodolphe

    2016-03-01

    Non-radiative Excitation Fluorescence Microscopy (NEFM) constitutes a new way to observe biological samples beyond the diffraction limit. Non-radiative excitation of the samples is achieved by coating the substrate with donor species, such as quantum dots (QDs). Thus the dyes are not excited directly by the laser source, as in common fluorescence microscopy, but through a non-radiative energy transfer. To prevent dewetting of the donor film, we have recently implemented a silanization process to covalently bond the QDs on the substrate. An homogeneous monolayer of QDs was then deposited on only one side of the coverslips. Atomic force microscopy was then used to characterize the QD layer. We highlight the potential of our method through the study of Giant Unilamellar Vesicles (GUVs) labeled with DiD as acceptor, in interaction with surface functionalized with poly-L-lysine. In the presence of GUVs, we observed a quenching of QDs emission, together with an emission of DiD located in the membrane, which clearly indicated that non-radiative energy transfer from QDs to DiD occurs.

  15. Atoms and Molecules Interacting with Light

    Science.gov (United States)

    van der Straten, Peter; Metcalf, Harold

    2016-02-01

    Part I. Atom-Light Interaction: 1. The classical physics pathway; Appendix 1.A. Damping force on an accelerating charge; Appendix 1.B. Hanle effect; Appendix 1.C. Optical tweezers; 2. Interaction of two-level atoms and light; Appendix 2.A. Pauli matrices for motion of the bloch vector; Appendix 2.B. The Ramsey method; Appendix 2.C. Echoes and interferometry; Appendix 2.D. Adiabatic rapid passage; Appendix 2.E Superposition and entanglement; 3. The atom-light interaction; Appendix 3.A. Proof of the oscillator strength theorem; Appendix 3.B. Electromagnetic fields; Appendix 3.C. The dipole approximation; Appendix 3.D. Time resolved fluorescence from multi-level atoms; 4. 'Forbidden' transitions; Appendix 4.A. Higher order approximations; 5. Spontaneous emission; Appendix 5.A. The quantum mechanical harmonic oscillator; Appendix 5.B. Field quantization; Appendix 5.C. Alternative theories to QED; 6. The density matrix; Appendix 6.A. The Liouville-von Neumann equation; Part II. Internal Structure: 7. The hydrogen atom; Appendix 7.A. Center-of-mass motion; Appendix 7.B. Coordinate systems; Appendix 7.C. Commuting operators; Appendix 7.D. Matrix elements of the radial wavefunctions; 8. Fine structure; Appendix 8.A. The Sommerfeld fine-structure constant; Appendix 8.B. Measurements of the fine structure 9. Effects of the nucleus; Appendix 9.A. Interacting magnetic dipoles; Appendix 9.B. Hyperfine structure for two spin =2 particles; Appendix 9.C. The hydrogen maser; 10. The alkali-metal atoms; Appendix 10.A. Quantum defects for the alkalis; Appendix 10.B. Numerov method; 11. Atoms in magnetic fields; Appendix 11.A. The ground state of atomic hydrogen; Appendix 11.B. Positronium; Appendix 11.C. The non-crossing theorem; Appendix 11.D. Passage through an anticrossing: Landau-Zener transitions; 12. Atoms in electric fields; 13. Rydberg atoms; 14. The helium atom; Appendix 14.A. Variational calculations; Appendix 14.B. Detail on the variational calculations of the ground state

  16. Effect of heavy atoms in bioluminescent reactions.

    Science.gov (United States)

    Kirillova, Tamara N; Kudryasheva, Nadezhda S

    2007-03-01

    Bioluminescent reactions of luminous organisms are excellent models for studying the effects of heavy atoms on enzymatic processes. The effects of potassium halides with halide anions of different atomic weight were compared in bioluminescent reactions of the firefly (Luciola mingrelica), a marine coelenterate (Obelia longissima), and a marine bacterium (Photobacterium leiognathi). Two mechanisms of the effects of the halides were examined-the physicochemical effect of the external heavy atom, based on spin-orbit interactions in electron-excited structures, and the biochemical effect, i.e. interactions with the enzymes resulting in changes of enzymatic activity. The physicochemical effect was evaluated by using photoexcitation of model fluorescent compounds (flavin mononucleotide, firefly luciferin, and coelenteramide) of similar structure to the bioluminescence emitters. The bioluminescent and photoluminescent inhibition coefficients were calculated and compared for the luminous organisms to evaluate the relative contributions of the two mechanisms. The biochemical mechanism was found to be dominant. Hence, the bioluminescent reactions can be used as assays to monitor enzyme inhibition, in metabolic processes, by Br or I-containing compounds.

  17. Sampling the Hydrogen Atom

    Directory of Open Access Journals (Sweden)

    Graves N.

    2013-01-01

    Full Text Available A model is proposed for the hydrogen atom in which the electron is an objectively real particle orbiting at very near to light speed. The model is based on the postulate that certain velocity terms associated with orbiting bodies can be considered as being af- fected by relativity. This leads to a model for the atom in which the stable electron orbits are associated with orbital velocities where Gamma is n /α , leading to the idea that it is Gamma that is quantized and not angular momentum as in the Bohr and other models. The model provides a mechanism which leads to quantization of energy levels within the atom and also provides a simple mechanical explanation for the Fine Struc- ture Constant. The mechanism is closely associated with the Sampling theorem and the related phenomenon of aliasing developed in the mid-20th century by engineers at Bell labs.

  18. Single atoms on demand for cavity QED experiments

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, I.

    2007-09-06

    Cavity quantum electrodynamics (cavity QED) describes electromagnetic fields in a confined space and the radiative properties of atoms in such fields. The simplest example of such system is a single atom interacting with one mode of a high-finesse resonator. Besides observation and exploration of fundamental quantum mechanical effects, this system bears a high potential for applications quantum information science such as, e.g., quantum logic gates, quantum communication and quantum teleportation. In this thesis I present an experiment on the deterministic coupling of a single neutral atom to the mode of a high-finesse optical resonator. In Chapter 1 I describe our basic techniques for trapping and observing single cesium atoms. As a source of single atoms we use a high-gradient magneto-optical trap, which captures the atoms from background gas in a vacuum chamber and cools them down to millikelvin temperatures. The atoms are then transferred without loss into a standing-wave dipole trap, which provides a conservative potential required for experiments on atomic coherence such as quantum information processing and metrology on trapped atoms. Moreover, shifting the standing-wave pattern allows us to deterministically transport the atoms (Chapter 2). In combination with nondestructive fluorescence imaging of individual trapped atoms, this enables us to control their position with submicrometer precision over several millimeters along the dipole trap. The cavity QED system can distinctly display quantum behaviour in the so-called strong coupling regime, i.e., when the coherent atom-cavity coupling rate dominates dissipation in the system. This sets the main requirements on the resonator's properties: small mode volume and high finesse. Chapter 3 is devoted to the manufacturing, assembling, and testing of an ultra-high finesse optical Fabry-Perot resonator, stabilized to the atomic transition. In Chapter 4 I present the transportation of single atoms into the

  19. Korean atomic bomb victims.

    Science.gov (United States)

    Sasamoto, Yukuo

    2009-01-01

    After colonizing Korea, Japan invaded China, and subsequently initiated the Pacific War against the United States, Britain, and their allies. Towards the end of the war, U.S. warplanes dropped atomic bombs on Hiroshima and Nagasaki, which resulted in a large number of Koreans who lived in Hiroshima and Nagasaki suffering from the effects of the bombs. The objective of this paper is to examine the history of Korea atomic bomb victims who were caught in between the U.S., Japan, the Republic of Korea (South Korea) and the Democratic People's Republic of Korea (North Korea).

  20. Optically pumped atoms

    CERN Document Server

    Happer, William; Walker, Thad

    2010-01-01

    Covering the most important knowledge on optical pumping of atoms, this ready reference is backed by numerous examples of modelling computation for optical pumped systems. The authors show for the first time that modern scientific computing software makes it practical to analyze the full, multilevel system of optically pumped atoms. To make the discussion less abstract, the authors have illustrated key points with sections of MATLAB codes. To make most effective use of contemporary mathematical software, it is especially useful to analyze optical pumping situations in the Liouville spa

  1. Hirshfeld atom refinement

    Directory of Open Access Journals (Sweden)

    Silvia C. Capelli

    2014-09-01

    Full Text Available Hirshfeld atom refinement (HAR is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly–l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree–Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs are freely refined without constraints or restraints – even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu's, all other structural parameters agree within less than 2 csu's. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules, the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å2 as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements – an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å.

  2. Atomic Force Microscope

    Energy Technology Data Exchange (ETDEWEB)

    Day, R.D.; Russell, P.E.

    1988-12-01

    The Atomic Force Microscope (AFM) is a recently developed instrument that has achieved atomic resolution imaging of both conducting and non- conducting surfaces. Because the AFM is in the early stages of development, and because of the difficulty of building the instrument, it is currently in use in fewer than ten laboratories worldwide. It promises to be a valuable tool for obtaining information about engineering surfaces and aiding the .study of precision fabrication processes. This paper gives an overview of AFM technology and presents plans to build an instrument designed to look at engineering surfaces.

  3. Atoms in Agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, Thomas S. [University of Tennessee

    1965-01-01

    Agriculture benefits from the applications of research. Radioactive techniques have been used to study soils, plants, microbes, insects, farm animals, and new ways to use and preserve foodstuffs. Radioactive atoms are not used directly by farmers but are used in research directed by the U. S. Department of Agriculture and Atomic Energy Commission, by the agricultural experiment stations of the various states, and by numerous public and private research institutions. From such research come improved materials and methods which are used on the farm.

  4. Fluorescence energy transfer in the bi-fluorescent S-layer tandem fusion protein ECFP-SgsE-YFP.

    Science.gov (United States)

    Kainz, Birgit; Steiner, Kerstin; Sleytr, Uwe B; Pum, Dietmar; Toca-Herrera, José L

    2010-12-01

    This work reports for the first time on the fabrication of a bi-functional S-layer tandem fusion protein which is able to self-assemble on solid supports without losing its functionality. Two variants of the green fluorescent protein (GFP) were genetically combined with a self-assembly system having the remarkable opportunity to interact with each other and act as functional nanopatterning biocoating. The S-layer protein SgsE of Geobacillus stearothermophilus NRS 2004/3a was fused with the cyan ECFP donor protein at the SgsE N-terminus and with the yellow YFP acceptor protein at the C-terminus. The fluorescence energy transfer was studied with spectrofluorimetry, confocal microscopy and flow cytometry, whilst protein self-assembly (on silicon dioxide particles) and structural investigations were carried out with atomic force microscopy (AFM). The fluorescence resonance energy transfer efficiency of reassembled SgsE tandem protein was 20.0 ± 6.1% which is almost the same transfer efficiency shown in solution (19.6 ± 0.1%). This work shows that bi-fluorescent S-layer fusion proteins self-assemble on silica particles retaining their fluorescent properties.

  5. $Ly \\alpha$ Fluorescent Excitation of FeII in Active Galactic Nuclei

    CERN Document Server

    Sigut, T A A; Pradhan, Anil K.

    1998-01-01

    We have calculated FeII emission line strengths for Active Galactic Nuclei Broad-Line Regions using precise radiative transfer and Iron Project atomic data. We improve the treatment of all previously considered excitation mechanisms for the FeII emission, continuum fluorescence, collisional excitation, fluorescence by self-overlap among the iron lines, and fluorescent excitation by Lyman-alpha. We demonstrate that Lyman-alpha fluorescence is of fundamental importance in determining the strength of the FeII emission. In addition to enhancing the ultraviolet and optical FeII flux, Lyman-alpha fluorescence also results in significant near-infrared FeII emission in the 8500-9500 Angstrom wavelength range. New observations are suggested to probe this effect in strong FeII emitting quasars.

  6. A benzothiazole-based fluorescent probe for distinguishing and bioimaging of Hg(2+) and Cu(2).

    Science.gov (United States)

    Gu, Biao; Huang, Liyan; Su, Wei; Duan, Xiaoli; Li, Haitao; Yao, Shouzhuo

    2017-02-15

    A new benzothiazole-based fluorescent probe 2-(benzo[d]thiazol-2-yl)-4-(1,3- dithian-2-yl)phenol (BT) with two different reaction sites, a thioacetal group (site 1 for Hg(2+)), and O and N atoms of the benzothiazole dye (site 2 for Cu(2+)), was designed and synthesized. The probe BT showed ratiometric fluorescent response to Hg(2+) and fluorescence quenching behavior to Cu(2+), which induces naked-eye fluorescent color changes from green to blue and colorless, respectively. Moreover, it displayed highly sensitivity and selectivity toward Hg(2+) and Cu(2+) without interference from other metal ions. The sensing mechanisms were also confirmed by (1)H NMR titration, mass spectrum and Job's plot analyses. Finally, probe BT was successfully used for fluorescent imaging of Hg(2+) and Cu(2+) in living cells, demonstrating its potential applications in biological science.

  7. Assessing Photosynthesis by Fluorescence Imaging

    Science.gov (United States)

    Saura, Pedro; Quiles, Maria Jose

    2011-01-01

    This practical paper describes a novel fluorescence imaging experiment to study the three processes of photochemistry, fluorescence and thermal energy dissipation, which compete during the dissipation of excitation energy in photosynthesis. The technique represents a non-invasive tool for revealing and understanding the spatial heterogeneity in…

  8. X-ray Fluorescence Sectioning

    CERN Document Server

    Cong, Wenxiang

    2012-01-01

    In this paper, we propose an x-ray fluorescence imaging system for elemental analysis. The key idea is what we call "x-ray fluorescence sectioning". Specifically, a slit collimator in front of an x-ray tube is used to shape x-rays into a fan-beam to illuminate a planar section of an object. Then, relevant elements such as gold nanoparticles on the fan-beam plane are excited to generate x-ray fluorescence signals. One or more 2D spectral detectors are placed to face the fan-beam plane and directly measure x-ray fluorescence data. Detector elements are so collimated that each element only sees a unique area element on the fan-beam plane and records the x-ray fluorescence signal accordingly. The measured 2D x-ray fluorescence data can be refined in reference to the attenuation characteristics of the object and the divergence of the beam for accurate elemental mapping. This x-ray fluorescence sectioning system promises fast fluorescence tomographic imaging without a complex inverse procedure. The design can be ad...

  9. Optical Properties of Fluorescent Dyes

    Institute of Scientific and Technical Information of China (English)

    李戎; 陈东辉

    2001-01-01

    Fluorescent dyes have been widely used these years.Because of the special optical performance, conventional CCM systems seem to be unable to predict the recipes of fabrics dyed with fluorescent dyes. In order to enhance the functions of CCM systems, the optical properties of fluorescent dyes in their absorption region were investigated. It has been found that there was a fixed maximum absorption wavelength for each fluorescent dyes whatever its concentration is. Both absorption region and maximum absorption wavelength of the dyes in solution are the same to those in fabric, and that the absorption is directly proportional to the concentration of the dye. So the optical properties obtained in solutions cna be applied for describing the optics performance of fluorescent dyes in fabrics.

  10. Fluorescence calibration method for single-particle aerosol fluorescence instruments

    Science.gov (United States)

    Shipley Robinson, Ellis; Gao, Ru-Shan; Schwarz, Joshua P.; Fahey, David W.; Perring, Anne E.

    2017-05-01

    Real-time, single-particle fluorescence instruments used to detect atmospheric bioaerosol particles are increasingly common, yet no standard fluorescence calibration method exists for this technique. This gap limits the utility of these instruments as quantitative tools and complicates comparisons between different measurement campaigns. To address this need, we have developed a method to produce size-selected particles with a known mass of fluorophore, which we use to calibrate the fluorescence detection of a Wideband Integrated Bioaerosol Sensor (WIBS-4A). We use mixed tryptophan-ammonium sulfate particles to calibrate one detector (FL1; excitation = 280 nm, emission = 310-400 nm) and pure quinine particles to calibrate the other (FL2; excitation = 280 nm, emission = 420-650 nm). The relationship between fluorescence and mass for the mixed tryptophan-ammonium sulfate particles is linear, while that for the pure quinine particles is nonlinear, likely indicating that not all of the quinine mass contributes to the observed fluorescence. Nonetheless, both materials produce a repeatable response between observed fluorescence and particle mass. This procedure allows users to set the detector gains to achieve a known absolute response, calculate the limits of detection for a given instrument, improve the repeatability of the instrumental setup, and facilitate intercomparisons between different instruments. We recommend calibration of single-particle fluorescence instruments using these methods.

  11. Atomic physics and reality

    CERN Multimedia

    1985-01-01

    An account of the long standing debate between Niels Bohr and Albert Einstein regarding the validity of the quantum mechanical description of atomic phenomena.With physicts, John Wheeler (Texas), John Bell (CERN), David Rohm (London), Abner Shimony (Boston), Alain Aspect (Paris)

  12. Energy from the Atom.

    Science.gov (United States)

    Smith, Patricia L.

    This curriculum guide was written to supplement fifth and sixth grade science units on matter and energy. It was designed to provide more in-depth material on the atom. The first part, "Teacher Guide," contains background information, biographical sketches of persons in the history of nuclear energy, vocabulary, answer sheets, management sheets…

  13. Atomically Traceable Nanostructure Fabrication.

    Science.gov (United States)

    Ballard, Josh B; Dick, Don D; McDonnell, Stephen J; Bischof, Maia; Fu, Joseph; Owen, James H G; Owen, William R; Alexander, Justin D; Jaeger, David L; Namboodiri, Pradeep; Fuchs, Ehud; Chabal, Yves J; Wallace, Robert M; Reidy, Richard; Silver, Richard M; Randall, John N; Von Ehr, James

    2015-07-17

    Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure.

  14. Chiral atomically thin films

    Science.gov (United States)

    Kim, Cheol-Joo; Sánchez-Castillo, A.; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, Jiwoong

    2016-06-01

    Chiral materials possess left- and right-handed counterparts linked by mirror symmetry. These materials are useful for advanced applications in polarization optics, stereochemistry and spintronics. In particular, the realization of spatially uniform chiral films with atomic-scale control of their handedness could provide a powerful means for developing nanodevices with novel chiral properties. However, previous approaches based on natural or grown films, or arrays of fabricated building blocks, could not offer a direct means to program intrinsic chiral properties of the film on the atomic scale. Here, we report a chiral stacking approach, where two-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack. Using this method, we produce left- and right-handed bilayer graphene, that is, a two-atom-thick chiral film. The film displays one of the highest intrinsic ellipticity values (6.5 deg μm-1) ever reported, and a remarkably strong circular dichroism (CD) with the peak energy and sign tuned by θ and polarity. We show that these chiral properties originate from the large in-plane magnetic moment associated with the interlayer optical transition. Furthermore, we show that we can program the chiral properties of atomically thin films layer-by-layer by producing three-layer graphene films with structurally controlled CD spectra.

  15. Atomic and Molecular Processes

    Science.gov (United States)

    1980-06-25

    The topics investigated experimentally and theoretically by the Pittsburgh Atomic Sciences Institute with applications to high power laser development and atmospheric IR backgrounds are enumerated. Reports containing the detailed scientific progress in these studies are cited. Finally, a list of the journal articles describing the results of the programs, with full references, is given.

  16. Single-Atom Electrocatalysts.

    Science.gov (United States)

    Zhu, Chengzhou; Fu, Shaofang; Shi, Qiurong; Du, Dan; Lin, Yuehe

    2017-05-23

    Recent years have witnessed the increasing production of the sustainable and renewable energy. The limitations of electrochemical performances are closely associated with the search for highly efficient electrocatalysts with more rational control of size, shape, composition and structure. Specifically, the rapidly emerging studies on single-atom catalysts (SACs) have sparked new interests in electrocatalysis because of the unique properties such as high catalytic activity, selectivity and 100% atom utilization. In this review, we introduce the innovative synthesis and advanced characterizations of SACs and primarily focus on their electrochemical applications in oxygen reduction/evolution reaction, hydrogen evolution reaction, hydrocarbon conversion reactions for fuel cells (methanol, ethanol and formic acid electrooxidation) and other related fields. Significantly, this unique single atom-depended electrocatalytic performance together with the underlying mechanism will also be discussed. Furthermore, future research directions and challenges are proposed to further realize the ultimate goal of tailoring single-atoms for electrochemical applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Atomic Particle Detection

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1970-01-01

    This booklet tells how scientists observe the particles and electromagnetic radiation that emerges from an atomic nucleus. The equipment used falls into two general categories: counters which count each particle as it passes by, and track detectors, which make a photographic record of the particle's track.

  18. Atomism, Pragmatism, Holism.

    Science.gov (United States)

    Miller, John P.

    1986-01-01

    Examines three world views influencing curriculum development--atomism (underpinning competency-based education), pragmatism (promoting inquiry-based approaches), amd holism (associated with confluent or Waldorf education). Holism embodies the perennial philosophy and attempts to integrate cognitive, affective, and transpersonal dimensions,…

  19. Experiments with Ξ- atoms

    Science.gov (United States)

    Batty, C. J.; Friedman, E.; Gal, A.

    1999-01-01

    Experiments with Ξ- atoms are proposed in order to study the nuclear interaction of Ξ hyperons. The production of Ξ- in the (K-,K+) reaction, the Ξ- stopping in matter, and its atomic cascade are incorporated within a realistic evaluation of the results expected for Ξ- x-ray spectra across the periodic table, using an assumed Ξ-nucleus optical potential Vopt. Several optimal targets for measuring the strong-interaction shift and width of the x-ray transition to the ``last'' atomic level observed are singled out: F, Cl, I, and Pb. The sensitivity of these observables to the parameters of Vopt is considered. The relevance of such experiments is discussed in the context of strangeness -2 nuclear physics and multistrange nuclear matter. Finally, with particular reference to searches for the H dibaryon, the properties of Ξ-d atoms are also discussed. The role of Stark mixing and its effect on S and P state capture of Ξ- by the deuteron together with estimates of the resulting probability for producing the H dibaryon are considered in detail.

  20. Ludwig Boltzmann: Atomic genius

    Energy Technology Data Exchange (ETDEWEB)

    Cercignani, C. [Department of Mathematics, Politecnico di Milano (Italy)]. E-mail: carcer@mate.polimi.it

    2006-09-15

    On the centenary of the death of Ludwig Boltzmann, Carlo Cercignani examines the immense contributions of the man who pioneered our understanding of the atomic nature of matter. The man who first gave a convincing explanation of the irreversibility of the macroscopic world and the symmetry of the laws of physics was the Austrian physicist Ludwig Boltzmann, who tragically committed suicide 100 years ago this month. One of the key figures in the development of the atomic theory of matter, Boltzmann's fame will be forever linked to two fundamental contributions to science. The first was his interpretation of 'entropy' as a mathematically well-defined measure of the disorder of atoms. The second was his derivation of what is now known as the Boltzmann equation, which describes the statistical properties of a gas as made up of molecules. The equation, which described for the first time how a probability can evolve with time, allowed Boltzmann to explain why macroscopic phenomena are irreversible. The key point is that while microscopic objects like atoms can behave reversibly, we never see broken coffee cups reforming because it would involve a long series of highly improbable interactions - and not because it is forbidden by the laws of physics. (U.K.)

  1. Molecular engineering and fluorescence for the detection of toxic cations; Ingenierie moleculaire et fluorescence pour la reconnaissance de cations toxiques

    Energy Technology Data Exchange (ETDEWEB)

    Souchon, V

    2007-11-15

    This work is a part of the 'Toxicologie Nucleaire Environnementale' program which aims at studying the effects on the living of heavy metals or radionuclides involved in nuclear industry. Most particularly, it deals with the design of new fluorescent sensors for the selective detection of Pb{sup 2+}, Cd{sup 2+} and Cs{sup +} in biological media. Several fluorescent calixarenes possessing nitrogen atoms were synthesized and their properties as potential lead sensors were investigated. One of them could be used in experimental conditions close to biological media and new target compounds with amide functional groups were proposed. Many approaches were considered for the design of selective fluorescent sensors for cadmium. On the basis of literature results, many chelating compounds incorporating sulfur atoms were synthesized but showed no significant affinity towards cadmium. On the opposite, compounds functionalized with several pyridine-2'-yl-1,2,3-triazol fluorescent moieties linked to a {beta}-cyclodextrin or a calix[4]arene showed good affinity for cadmium in methanol, but the selectivity was found to be insufficient. In contrast, very satisfying results in terms of both selectivity and sensitivity could be obtained with the commercial calcium sensor Rhod-5N in an aqueous medium at neutral pH. Lastly, micromolar detection limits for the selective detection of caesium were reached in an aqueous medium at neutral pH thanks to a new sulfonated fluorescent calixarene with two appended crown-ethers. An original complexation mechanism was proposed and validated by molecular modelling (DFT). (author)

  2. Single Molecule Spectroscopy of Fluorescent Proteins

    NARCIS (Netherlands)

    Blum, Christian; Subramaniam, Vinod

    2009-01-01

    The discovery and use of fluorescent proteins has revolutionized cellular biology. Despite the widespread use of visible fluorescent proteins as reporters and sensors in cellular environments the versatile photophysics of fluorescent proteins is still subject to intense research. Understanding the

  3. Control of light trapping in a large atomic system by a static magnetic field

    Science.gov (United States)

    Skipetrov, S. E.; Sokolov, I. M.; Havey, M. D.

    2016-07-01

    We propose to control light trapping in a large ensemble of cold atoms by an external, static magnetic field. For an appropriate choice of frequency and polarization of the exciting pulse, the field is expected to speed up the fluorescence of a dilute atomic system. In a dense ensemble, the field does not affect the early-time superradiant signal but amplifies intensity oscillations at intermediate times and induces a very slow, nonexponential long-time decay. The slowing down of fluorescence is due to the excitation of spatially localized collective atomic states that appear only under a strong magnetic field and have exponentially long lifetimes. Our results therefore pave a way towards experimental observation of the disorder-induced localization of light in cold atomic systems.

  4. FLEX: fluorescence explorer

    Science.gov (United States)

    Stoll, Marc-Ph.; Court, Andrew; Smorenburg, Kees; Visser, Huib; Crocco, Luiggi; Heilimo, Jyro; Honig, Andre

    1999-12-01

    FLEX is a scientifically driven space mission to provide demonstration/validation of the instrumentation and technique for measuring the natural fluorescence of vegetation in the Fraunhofer lines. The payload consists of high spectral resolution (0.1 - 0.3 nm) CCD imaging grating spectrometer with two channels: one in the red (648 - 664 nm) and one in the blue (391 - 438 nm) for working with several Fraunhofer lines. The across track FOV is 8.4 degrees; ground spatial resolution is better than 0.5 X 0.5 km2. To increase the S/N ratio a steering mirror will be used, if necessary, to 'freeze' the image and also to provide plus or minus 4 degrees across track depointing. Calibration is made by viewing the sun via a diffuser plate switched into the telescope field of view. A separate CCD camera will allow cloud detection and scene identification. A TIR radiometer will provide simultaneous surface temperature measurements. The spacecraft, overall mass estimated at 200 kg, is derived from the ASI-MITA bus which provides all the necessary subsystems and stabilized platform. By use of on-board storage, ground requirements for satellite control and data link are minimized; the possibility of local stations for real time reception/distribution is also envisaged. Provisional orbit characteristics are: LEO sun synchronous, 500 - 900 km altitude. Priority will be given to highest revisit frequency on a sufficient number of selected test sites.

  5. Fluorescent blood cell angiography

    Science.gov (United States)

    Ben-nun, Joshua; Constable, Ian J.

    1994-06-01

    Fluorescein angiography is currently the main method for evaluation of the retinal vascular patency. Ashton noted that capillary patency to the small fluorescein molecule may differ from that of the larger red blood cells. He concluded that fluorescein angiography is not able to demonstrate a developing stenosis, that might be the precipitating cause of a later capillary closure in various microvasculopathies. Sarelius et al have shown, in hamster cheek pouch and cremaster muscle, that fluorescently labeled erythrocytes in known concentrations can be used for the direct measurement of capillary flow parameters. The only assumption that this method relies on, is that the labeled cells are rheologically normal and therefore reflect the behavior of the total cell population. We have developed a new method for an in-vivo, real-time demonstration of the blood cell flow in the retinal capillary net. Based on the assumption presented by Sarelius et al, measurement and analysis of the retinal capillary blood cell flow is also possible from the results achieved by the new method.

  6. Fluorescence endoscopy and photodynamic therapy.

    Science.gov (United States)

    Messmann, H; Endlicher, E; Gelbmann, C M; Schölmerich, J

    2002-10-01

    Fluorescence endoscopy is a new technique which allows a better detection of non-visible malignant or premalignant lesions or, those which are difficult to detect. Exogenously applied sensitisers accumulate selectively in malignant lesions and induce fluorescence after illumination with light of adequate wavelength. However, also endogenous fluorophores, different located in malignant or benign lesions, induce a different autofluorescence in these lesions. Tissue fluorescence can be detected by optical sampling of the mucosa using fluorescence spectroscopy or by generating real time fluorescence images with specialised camera systems. Compared to point fluorescence spectroscopy the latter technique enables the screening of large surface areas of mucosa. Meanwhile, fluorescence endoscopy is a widely used technique in urology employing 5-aminolaevulinic acid sensitisation. In gastroenterology, this technique seems promising for the detection of early cancers or dysplasia in patients with Barrett's oesophagus or ulcerative colitis. Using different sensitisers, photodynamic therapy seems to be a promising option for patients with advanced oesophageal cancer and in the palliative treatment of non-resectable bile duct cancer, furthermore for patients with early gastric cancer and dysplasia in Barrett's oesophagus. Probably, by laser light fractionation or a combination of different sensitisers, an enhanced effect can be expected.

  7. Absorption imaging of ultracold atoms on atom chips

    DEFF Research Database (Denmark)

    Smith, David A.; Aigner, Simon; Hofferberth, Sebastian

    2011-01-01

    Imaging ultracold atomic gases close to surfaces is an important tool for the detailed analysis of experiments carried out using atom chips. We describe the critical factors that need be considered, especially when the imaging beam is purposely reflected from the surface. In particular we present...... methods to measure the atom-surface distance, which is a prerequisite for magnetic field imaging and studies of atom surface-interactions....

  8. Atomic Coherent Trapping and Properties of Trapped Atom

    Institute of Scientific and Technical Information of China (English)

    YANG Guo-Jian; XIA Li-Xin; XIE Min

    2006-01-01

    Based on the theory of velocity-selective coherent population trapping, we investigate an atom-laser system where a pair of counterpropagating laser fields interact with a three-level atom. The influence of the parametric condition on the properties of the system such as velocity at which the atom is selected to be trapped, time needed for finishing the coherent trapping process, and possible electromagnetically induced transparency of an altrocold atomic medium,etc., is studied.

  9. Imaging a single atom in a time-of-flight experiment

    Energy Technology Data Exchange (ETDEWEB)

    Fuhrmanek, A; Tuchendler, C; Grangier, P; Sortais, Y R P; Browaeys, A [Laboratoire Charles Fabry, Institut d' Optique, CNRS, Universite de Paris-Sud, Campus Polytechnique, 2 avenue Augustin Fresnel, RD 128, 91127 Palaiseau Cedex (France); Lance, A M, E-mail: yvan.sortais@institutoptique.f [Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, MD 20899 (United States)

    2010-05-15

    We perform fluorescence imaging of a single {sup 87}Rb atom after its release from an optical dipole trap. The time-of-flight expansion of the atomic spatial density distribution is observed by accumulating many single atom images. The position of the atom is revealed with a spatial resolution close to 1 {mu}m by a single-photon event, induced by a short resonant probe. The expansion yields a measure of the temperature of a single atom, which is in very good agreement with the value obtained by an independent measurement based on a release-and-recapture method. The analysis presented in this paper provides a way of calibrating an imaging system useful for experimental studies involving a few atoms confined in a dipole trap.

  10. Non-covalently Functionalized Fluorescent Carbon Nanotubes: A Supramolecular Approach of Selective Zinc Ions Sensing in Living Cells%Non-covalently Functionalized Fluorescent Carbon Nanotubes: A Supramolecular Approach of Selective Zinc Ions Sensing in Living Cells

    Institute of Scientific and Technical Information of China (English)

    刘玉萍; 陈湧; 张宁; 刘育

    2012-01-01

    A fluorescent cyclodextrin/carbon nanotube assembly was easily constructed through the non-covalent attach- ment of adamantanylpyrene on carbon nanotube and the following association of cyclodextrin derivative bearing fluorescent substituent, and its structure was fully characterized by UV/Vis/NIR spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and atomic force microscopy. Fluorescence spectroscopic and fluorescence microscopic studies showed that the resultant non-covalently functionalized fluo- rescent nanotube could be used as a highly selective fluorescent probe for Zn2+ in both water and living cells. Without carbon nanotube, the fluorescence probe was unable to enter the cell but only anchored on the cell mem- brane. This approach will overcome the disadvantage of many spectral sensors that are unable to enter living cells and greatly improve the application of naotube-related supramolecular architecture in nanoscience and technology.

  11. A Transportable Gravity Gradiometer Based on Atom Interferometry

    Science.gov (United States)

    Yu, Nan; Thompson, Robert J.; Kellogg, James R.; Aveline, David C.; Maleki, Lute; Kohel, James M.

    2010-01-01

    rest frame for the trapped atoms. While still in this moving-frame molasses, the laser frequencies are further detuned from the atomic resonance (while maintaining this relative frequency shift) to cool the atom cloud's temperature to 2 K or below, corresponding to an rms velocity of less than 2 cm/s. After launch, the cold atoms undergo further state and velocity selection to prepare for atom interferometry. The atom interferometers are then realized using laser-induced stimulated Raman transitions to perform the necessary manipulations of each atom, and the resulting interferometer phase is measured using laser-induced fluorescence for state-normalized detection. More than 20 laser beams with independent controls of frequency, phase, and intensity are required for this measurement sequence. This instrument can facilitate the study of Earth's gravitational field from surface and air vehicles, as well as from space by allowing gravity mapping from a low-cost, single spacecraft mission. In addition, the operation of atom interferometer-based instruments in space offers greater sensitivity than is possible in terrestrial instruments due to the much longer interrogation times available in the microgravity environment. A space-based quantum gravity gradiometer has the potential to achieve sensitivities similar to the GRACE mission at long spatial wavelengths, and will also have resolution similar to GOCE for measurement at shorter length scales.

  12. Distribution of populations in excited states of electrodeless discharge lamp of Rb atoms

    Institute of Scientific and Technical Information of China (English)

    TAO ZhiMing; WANG YanFei; HONG YeLong; WANG DongYing; ZHANG ShengNan; ZHUANG Wei; CHEN JingBiao

    2013-01-01

    The intensity of fluorescence spectral lines of Rb atoms in the region of 350-1110 nm is measured in eletrodeless discharge lamp.The population ratio between the excited states is calculated according to the spontaneous transition probabilities with rate equations.At the same time,the population density of energy level is also obtained.The results provide the potential applications of electrodeless discharge lamp in atomic filter and optical frequency reference at higher excited states without a pumping laser.

  13. Precision measurement of transverse velocity distribution of a strontium atomic beam

    OpenAIRE

    Gao, F.; H. Liu; Xu, P.; X. Tian; Y. Wang; Ren, J; Haibin Wu; Hong Chang

    2014-01-01

    We measure the transverse velocity distribution in a thermal Sr atomic beam precisely by velocity-selective saturated fluorescence spectroscopy. The use of an ultrastable laser system and the narrow intercombination transition line of Sr atoms mean that the resolution of the measured velocity can reach 0.13 m/s, corresponding to 90$\\mu K$ in energy units. The experimental results are in very good agreement with the results of theoretical calculations. Based on the spectroscopic techniques use...

  14. Radio-Frequency Field-Induced Quantum Interference Effects in Cold Atoms

    Institute of Scientific and Technical Information of China (English)

    龙全; 周蜀渝; 周善钰; 王育竹

    2001-01-01

    We propose constructing a quantum interference configuration for cold atoms in a magneto-optical trap by applying a radio frequency field, which coherently couples adjacent Zeeman sublevels, in combination with a repumping laser field. One effect of this interference is that a dip exists in the absorption of the repumping light when the radio frequency is scanned. Our prediction has been indirectly detected through the fluorescence of cold atoms in a preliminary experiment.

  15. Novel Water Soluble Fluorescent Trimethine Indocyanines Containing N-p-Carboxybenzyl Group

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Two fluorescent indocyanine dyes containing at least one p-carboxybenzyl group on the nitrogen atoms in the hetcrocyclic rings were designed and synthesized. Their absorption maxima were 549 nm and 551 nm in water respectively. They had good water solubility and photostability.

  16. P2O5 assisted green synthesis of multicolor fluorescent water soluble carbon dots.

    Science.gov (United States)

    Babar, Dipak Gorakh; Sonkar, Sumit Kumar; Tripathi, Kumud Malika; Sarkar, Sabyasachi

    2014-03-01

    A low cost synthesis of multicolor fluorescent carbon dots (C-dots) from edible sugars is described here. Common sugars like dextrose, lactose or maltose in aqueous medium gets dehydrated using phosphorus pentoxide (P2O5). The reaction is facile and completed within few minutes to form insoluble carbon (C-dots) mostly having the graphitic (G-band, Raman) sp2 hybridized carbon atoms (C-atoms). This insoluble carbon on oxidative treatment with nitric acid produced disordered sp3 (D-band retaining G-band, Raman) hybridized C-atoms, originated from the graphitic pool with sp2 hybridized C-atoms. This high density assimilation of self passivated "surfacial defects" become emissive during electronic transitions. Surfacial defects due to high degree of electrophilic carboxylation create the water soluble version of multicolor fluorescent C-dots as "water soluble fluorescent carbon dots" (wsFCDs). wsFCDs being itself self-passivated imposes the tunable multicolor emission throughout the visible spectrum without having any external coating and surface passivation and could be used as multicolor fluorescent probe especially in the emerging field of optical bio-imaging.

  17. Production of Excited Atomic Hydrogen from Methane

    Science.gov (United States)

    Machacek, J. R.; Andrianarijaona, V. M.; Furst, J. E.; Gay, T. J.; Kilcoyne, A. L. D.; Landers, A. L.; McLaughlin, K. W.

    2009-05-01

    We have measured the production of Lyα and Hα fluorescence from atomic H for the photodissociation of CH4 by linearly-polarized photons with energies between 20 and 65 eV. Comparison between our Lyα relative cross section and that previously reported [1] show different peak height ratios. This also occurs in the Hα cross section when compared to previous data [2]. We do not observe as significant a drop in either cross section above 35 eV. Our measurements were taken with pressures two orders of magnitude lower than those used in ref. [1]. We present comparisons between data sets and a discussion of possible systematic effects. [1] H. Fukuzawa et al., J. Phys. B. 38, 565 (2005). [2] M. Kato et al., J. Phys. B. 35, 4383 (2002). Support provided by the NSF (Grant PHY-0653379), DOE (LBNL/ALS) and ANSTO (Access to Major Research Facilities Programme).

  18. Optical atomic clocks

    CERN Document Server

    Poli, N; Gill, P; Tino, G M

    2014-01-01

    In the last ten years extraordinary results in time and frequency metrology have been demonstrated. Frequency-stabilization techniques for continuous-wave lasers and femto-second optical frequency combs have enabled a rapid development of frequency standards based on optical transitions in ultra-cold neutral atoms and trapped ions. As a result, today's best performing atomic clocks tick at an optical rate and allow scientists to perform high-resolution measurements with a precision approaching a few parts in $10^{18}$. This paper reviews the history and the state of the art in optical-clock research and addresses the implementation of optical clocks in a possible future redefinition of the SI second as well as in tests of fundamental physics.

  19. Rotary cup slurry atomization

    Science.gov (United States)

    Sommer, H. T.; Marnicio, R. J.

    1983-06-01

    The theory of a two-phase flow in a rotating cup atomizer is described. The analysis considers the separation of the solid and liquid media thus realistically modeling the flow of two layers along the inner cup wall: a slurry of increasing solids concentration and a supernatent liquid layer. The analysis is based on the earlier work of Hinze and Milborn (1950) which addressed the flow within a rotary cup for a homogeneous liquid. The superimposition of a settling velocity under conditions of high centrifugal acceleration permits the extended analysis of the separation of the two phases. Appropriate boundary conditions have been applied to the film's free surface and the cup wall and to match the flow characteristics at the liquid-slurry interface. The changing slurry viscosity, increasing nonlinearly with growing solid loading, was also considered. A parameter study illustrates the potential for a cup design to provide optimal slurry and liquid film thicknesses for effective atomization.

  20. Cavity enhanced atomic magnetometry

    CERN Document Server

    Crepaz, Herbert; Dumke, Rainer

    2015-01-01

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage that they can be effectively coated inside with a spin relaxation suppressing layer providing long spin coherence times without addition of a buffer gas. Cavity enhancement shows in an increase in optical polarization rotation and sensitivity compared to single-pass configurations.