WorldWideScience

Sample records for two-line atomic fluorescence

  1. Atomic-fluorescence spectrophotometry

    International Nuclear Information System (INIS)

    Bakhturova, N.F.; Yudelevich, I.G.

    1975-01-01

    Atomic-fluorescence spectrophotometry, a comparatively new method for the analysis of trace quantities, has developed rapidly in the past ten years. Theoretical and experimental studies by many workers have shown that atomic-fluorescence spectrophotometry (AFS) is capable of achieving a better limit than atomic absorption for a large number of elements. The present review examines briefly the principles of atomic-fluorescence spectrophotometry and the types of fluorescent transition. The excitation sources, flame and nonflame atomizers, used in AFS are described. The limits of detection achieved up to the present, using flame and nonflame methods of atomization are given

  2. Flame emission, atomic absorption and fluorescence spectrometry

    International Nuclear Information System (INIS)

    Horlick, G.

    1980-01-01

    Six hundred and thirty references are cited in this review. The information in the review is divided into 12 major areas: books, reviews, and bibliographies; fundamental studies in flames; developments in instrumentation; measurement techniques and procedure; flame emission spectrometry; flame atomic absorption spectrometry; flame molecular absorption spectrometry; electrothermal atomization atomic absorption spectroscopy; hydride generation techniques; graphite furnace atomic emission spectrometry; atomic fluorescence spectrometry; and analytical comparisons

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

    Science.gov (United States)

    Horlick, Gary

    1984-01-01

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

  4. Laser fluorescence spectroscopy of sputtered uranium atoms

    International Nuclear Information System (INIS)

    Wright, R.B.; Pellin, M.J.; Gruen, D.M.; Young, C.E.

    1979-01-01

    Laser induced fluorescence (LIF) spectroscopy was used to study the sputtering of 99.8% 238 U metal foil when bombarded by normally incident 500 to 3000 eV Ne + , Ar + , Kr + , and O 2 + . A three-level atom model of the LIF processes is developed to interpret the observed fluorescent emission from the sputtered species. The model shows that close attention must be paid to the conditions under which the experiment is carried out as well as to the details of the collision cascade theory of sputtering. Rigorous analysis shows that when properly applied, LIF can be used to investigate the predictions of sputtering theory as regards energy distributions of sputtered particles and for the determination of sputtering yields. The possibility that thermal emission may occur during sputtering can also be tested using the proposed model. It is shown that the velocity distribution (either the number density or flux density distribution, depending upon the experimental conditions) of the sputtered particles can be determined using the LIF technique and that this information can be used to obtain a description of the basic sputtering mechanisms. These matters are discussed using the U-atom fluorescence measurements as a basis. The relative sputtering yields for various incident ions on uranium were also measured for the first time using the LIF technique. A surprisingly high fraction of the sputtered uranium atoms were found to occupy the low lying metastable energy levels of U(I). The population of the sputtered metastable atoms were found approximately to obey a Boltzman distribution with an effective temperature of 920 +- 100 0 K. 41 references

  5. Atomic emission and atomic fluorescence spectroscopy in the direct current plasma

    International Nuclear Information System (INIS)

    Hendrick, M.S.

    1985-01-01

    The Direct Current Plasma (DCP) was investigated as a source for Atomic Emission (AE) and Atomic Fluorescence Spectrometry (AFS). The DCP was optimized for AE analyses using simplex optimization and Box-Behnken partial factorial experimental design, varying argon flows, and plasma position. Results were compared with a univariate search carried out in the region of the simplex optimum. Canonical analysis demonstrated that no true optimum exists for sensitivity, precision, or drift. A stationary ridge, where combinations of conditions gave comparable instrumental responses, was found. The DCP as an excitation source for AFS in a flame was used for diagnostic studies of the DCP. Moving the aerosol introduction tube behind the DCP with respect to the flame improved the characteristics of the DCP as a narrow line source, although self-absorption was observed at high concentrations of metal salt solutions in the DCP. Detection limits for Cd, Co, Cr, Cu, Fe, Mg, Mn, Zn, and Ni were in the low ng/mL region. Theoretical expressions for scatter correction with a two-line technique were derived, although no correction was necessary to achieve accurate results for standard reference materials

  6. Resonance fluorescence based two- and three-dimensional atom localization

    Science.gov (United States)

    Wahab, Abdul; Rahmatullah; Qamar, Sajid

    2016-06-01

    Two- and three-dimensional atom localization in a two-level atom-field system via resonance fluorescence is suggested. For the two-dimensional localization, the atom interacts with two orthogonal standing-wave fields, whereas for the three-dimensional atom localization, the atom interacts with three orthogonal standing-wave fields. The effect of the detuning and phase shifts associated with the corresponding standing-wave fields is investigated. A precision enhancement in position measurement of the single atom can be noticed via the control of the detuning and phase shifts.

  7. Studying atomic-resolution by X-ray fluorescence holography

    International Nuclear Information System (INIS)

    Gao Hongyi; Chen Jianwen; Xie Honglan; Zhu Huafeng; Li Ruxin; Xu Zhizhan

    2005-01-01

    In this work, the results of numerical simulations of X-ray fluorescence holograms and the reconstructed atomic images for Fe single crystal are given. The influences of the recording angles ranges and the polarization effect on the reconstruction of the atomic images are discussed. The process for removing twin images by multiple energy fluorescence holography and expanding the energy range of the incident X-rays to improve the resolution of the reconstructed images is presented

  8. Resonance fluorescence from an atom in a squeezed vacuum

    Science.gov (United States)

    Carmichael, H. J.; Lane, A. S.; Walls, D. F.

    1987-06-01

    The fluorescent spectrum for a two-level atom which is damped by a squeezed vacuum shows striking differences from the spectrum for ordinary resonance fluorescence. For strong coherent driving fields the Mollow triplet depends on the relative phase of the driving field and the squeezed vacuum field. The central peak may have either subnatural linewidth or supernatural linewidth depending on this phase. The mean atomic polarization also shows a phase sensitivity.

  9. Development of laser excited atomic fluorescence and ionization methods

    International Nuclear Information System (INIS)

    Winefordner, J.D.

    1991-01-01

    Progress report: May 1, 1988 to December 31, 1991. The research supported by DE-FG05-88ER13881 during the past (nearly) 3 years can be divided into the following four categories: (1) theoretical considerations of the ultimate detection powers of laser fluorescence and laser ionization methods; (2) experimental evaluation of laser excited atomic fluorescence; (3) fundamental studies of atomic and molecular parameters in flames and plasmas; (4) other studies

  10. Atomic fluorescence spectrometry with the inductively coupled plasma

    International Nuclear Information System (INIS)

    Omenetto, N.; Winefordner, J.D.

    1987-01-01

    Atomic fluorescence spectrometry (AFS) is based on the radiational activation of atoms and ions produced in a suitable atomizer (ionizer) and the subsequent measurement of the resulting radiational deactivation, called fluorescence. Atomic fluorescence spectrometry has been of considerable interest to researchers in atomic spectrometry because of its use for both analytical and diagnostic purposes. Unfortunately, the analytical applications of AFS have suffered from the lack of commercial instrumentation until the recent marketing of the Baird multiple-element, hollow cathode lamp-excited inductively coupled plasma system. This chapter is concerned strictly with the use of the inductively coupled plasma (ICP) as a cell and as a source for AFS. Many of the major references concerning the ICP in analytical AFS are categorized in Table 9.1, along with several reviews and diagnostical studies. For more detailed discussions of the fundamental aspects of AFS, the reader is referred to previous reviews

  11. Theory of analytical curves in atomic fluorescence flame spectrometry

    NARCIS (Netherlands)

    Hooymayers, H.P.

    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

  12. Multielement methods of atomic fluorescence analysis of enviromental samples

    International Nuclear Information System (INIS)

    Rigin, V.I.

    1985-01-01

    A multielement method of atomic fluorescence analysis of environmental samples based on sample decomposition by autoclave fluorination and gas-phase atomization of volatile compounds in inductive araon plasma using a nondispersive polychromator is suggested. Detection limits of some elements (Be, Sr, Cd, V, Mo, Te, Ru etc.) for different sample forms introduced in to an analyzer are given

  13. Laser-induced fluorescence line narrowing in atomic vapors

    International Nuclear Information System (INIS)

    Meier, T.; Schuessler, H.A.

    1983-01-01

    The use of highly monochromatic light allows the selective excitation of atoms in vapors if excitation and detection of the fluorescence is carried out collinearly. The atoms capable of absorbing light then form an atomic beam of well defined velocity along the direction of the laser beam, but no velocity selection occurs perpendicular to it. The potential of the technique for Doppler-free atomic spectroscopy and for the study of excited atom collisions is demonstrated using the Na D 1 line as an example

  14. 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.

  15. 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...

  16. TRACE ANALYSIS BY LASER-EXCITED ATOMIC FLUORESCENCE WITH ATOMIZATION IN A PULSED PLASMA

    OpenAIRE

    Lunyov , O.; Oshemkov , S.; Petrov , A.

    1991-01-01

    The possibilities of plasma atomization for laser fluorescence trace analysis are discussed. Pulsed hot hollow cathode discharge was used for analysis of solutions and powdered samples. The high voltage spark and laser-induced breakdown (laser spark) were used as atomizers of metal-containing atmospheric aerosols. Detection limits were improved by means of temporal background selection.

  17. Ultratrace determination of lead in whole blood using electrothermal atomization laser-excited atomic fluorescence spectrometry.

    Science.gov (United States)

    Wagner, E P; Smith, B W; Winefordner, J D

    1996-09-15

    Laser-excited atomic fluorescence has been used to detect lead that was electrothermally atomized from whole blood in a graphite furnace. A 9 kHz repetition rate copper vapor laser pumped dye laser was used to excite the lead at 283.3 nm, and the resulting atomic fluorescence was detected at 405.8 nm. No matrix modification was used other than a 1:21 dilution of the whole blood with high-purity water. Using the atomic fluorescence peak area as the analytical measure and a background correction technique based upon a simultaneous measurement of the transmitted laser intensity, excellent agreement for NIST and CDC certified whole blood reference samples was obtained with aqueous standards. A limit of detection in blood of 10 fg/mL (100 ag absolute) was achieved.

  18. Imaging atoms from resonance fluorescence spectrum beyond the diffraction limit

    Science.gov (United States)

    Liao, Zeyang; Al-Amri, Mohammad; Zubairy, M. Suhail

    2014-03-01

    We calculate the resonance fluorescence spectrum of a linear chain of two-level atoms driven by a gradient coherent laser field. The result shows that we can determine the positions of atoms from the spectrum even when the atoms locate within subwavelength range and the dipole-dipole interaction is significant. This far-field resonance fluorescence localization microscopy method does not require point-by-point scanning and it may be more time-efficient. We also give a possible scheme to extract the position information in an extended region without requiring more peak power of laser. We also briefly discuss how to do a 2D imaging based on our scheme. This work is supported by grants from the King Abdulaziz City for Science and Technology (KACST) and the Qatar National Research Fund (QNRF) under the NPRP project.

  19. Atomization of volatile compounds for atomic absorption and atomic fluorescence spectrometry: On the way towards the ideal atomizer

    International Nuclear Information System (INIS)

    Dedina, Jiri

    2007-01-01

    This review summarizes and discusses the individual atomizers of volatile compounds. A set of criteria important for analytical praxis is used to rank all the currently existing approaches to the atomization based on on-line atomization for atomic absorption (AAS) and atomic fluorescence spectrometry (AFS) as well as on in-atomizer trapping for AAS. Regarding on-line atomization for AAS, conventional quartz tubes are currently the most commonly used devices. They provide high sensitivity and low baseline noise. Running and investment costs are low. The most serious disadvantage is the poor resistance against atomization interferences and often unsatisfactory linearity of calibration graphs. Miniature diffusion flame (MDF) is extremely resistant to interferences, simple, cheap and user-friendly. Its essential disadvantage is low sensitivity. A novel device, known as a multiatomizer, was designed to overcome disadvantages of previous atomizers. It matches performance of conventional quartz tubes in terms of sensitivity and baseline noise as well as in running and investment costs. The multiatomizer, however, provides much better (i) resistance against atomization interferences and (ii) linearity of calibration graphs. In-atomizer trapping enhances the sensitivity of the determination and eliminates the effect of the generation kinetics and of surges in gas flow on the signal shape. This is beneficial for the accuracy of the determination. It could also be an effective tool for reducing some interferences in the liquid phase. In-situ trapping in graphite furnaces (GF) is presently by far the most popular approach to the in-atomizer trapping. Its resistance against interferences is reasonably good and it can be easily automated. In-situ trapping in GF is a mature method well established in various application fields. These are the reasons to rank in-situ trapping in GF as currently the most convenient approach to hydride atomization for AAS. The recently suggested

  20. State-dependent fluorescence of neutral atoms in optical potentials

    Science.gov (United States)

    Martinez-Dorantes, M.; Alt, W.; Gallego, J.; Ghosh, S.; Ratschbacher, L.; Meschede, D.

    2018-02-01

    Recently we have demonstrated scalable, nondestructive, and high-fidelity detection of the internal state of 87Rb neutral atoms in optical dipole traps using state-dependent fluorescence imaging [M. Martinez-Dorantes, W. Alt, J. Gallego, S. Ghosh, L. Ratschbacher, Y. Völzke, and D. Meschede, Phys. Rev. Lett. 119, 180503 (2017), 10.1103/PhysRevLett.119.180503]. In this paper we provide experimental procedures and interpretations to overcome the detrimental effects of heating-induced trap losses and state leakage. We present models for the dynamics of optically trapped atoms during state-dependent fluorescence imaging and verify our results by comparing Monte Carlo simulations with experimental data. Our systematic study of dipole force fluctuations heating in optical traps during near-resonant illumination shows that off-resonant light is preferable for state detection in tightly confining optical potentials.

  1. Measurement of fluorescence emission spectrum of few strongly driven atoms using an optical nanofiber.

    Science.gov (United States)

    Das, Manoj; Shirasaki, A; Nayak, K P; Morinaga, M; Le Kien, Fam; Hakuta, K

    2010-08-02

    We show that the fluorescence emission spectrum of few atoms can be measured by using an optical nanofiber combined with the optical heterodyne and photon correlation spectroscopy. The observed fluorescence spectrum of the atoms near the nanofiber shows negligible effects of the atom-surface interaction and agrees well with the Mollow triplet spectrum of free-space atoms at high excitation intensity.

  2. Resonance fluorescence microscopy via three-dimensional atom localization

    Science.gov (United States)

    Panchadhyayee, Pradipta; Dutta, Bibhas Kumar; Das, Nityananda; Mahapatra, Prasanta Kumar

    2018-02-01

    A scheme is proposed to realize three-dimensional (3D) atom localization in a driven two-level atomic system via resonance fluorescence. The field arrangement for the atom localization involves the application of three mutually orthogonal standing-wave fields and an additional traveling-wave coupling field. We have shown the efficacy of such field arrangement in tuning the spatially modulated resonance in all directions. Under different parametric conditions, the 3D localization patterns originate with various shapes such as sphere, sheets, disk, bowling pin, snake flute, flower vase. High-precision localization is achieved when the radiation field detuning equals twice the combined Rabi frequencies of the standing-wave fields. Application of a traveling-wave field of suitable amplitude at optimum radiation field detuning under symmetric standing-wave configuration leads to 100% detection probability even in sub-wavelength domain. Asymmetric field configuration is also taken into consideration to exhibit atom localization with appreciable precision compared to that of the symmetric case. The momentum distribution of the localized atoms is found to follow the Heisenberg uncertainty principle under the validity of Raman-Nath approximation. The proposed field configuration is suitable for application in the study of atom localization in an optical lattice arrangement.

  3. Numerical simulation study for atomic-resolution x-ray fluorescence holography

    International Nuclear Information System (INIS)

    Xie Honglan; Gao Hongyi; Chen Jianwen; Xiong Shisheng; Xu Zhizhan; Wang Junyue; Zhu Peiping; Xian Dingchang

    2003-01-01

    Based on the principle of x-ray fluorescence holography, an iron single crystal model of a body-centred cubic lattice is numerically simulated. From the fluorescence hologram produced numerically, the Fe atomic images were reconstructed. The atomic images of the (001), (100), (010) crystallographic planes were consistent with the corresponding atomic positions of the model. The result indicates that one can obtain internal structure images of single crystals at atomic-resolution by using x-ray fluorescence holography

  4. Containerless high temperature property measurements by atomic fluorescence

    Science.gov (United States)

    Schiffman, R. A.; Walker, C. A.

    1984-01-01

    Laser induced fluorescence (LIF) techniques for containerless study of high temperature processes and material properties was studied. Gas jet and electromagnetic levitation and electromagnetic and laser heating techniques are used with LIF in earth-based containerless high temperature experiments. Included are the development of an apparatus and its use in the studies of (1) chemical reactions on Al2O3, molybdenum, tungsten and LaB6 specimens, (2) methods for noncontact specimen temperature measurement, (3) levitation jet properties and (4) radiative lifetime and collisional energy transfer rates for electronically excited atoms.

  5. 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

  6. Laser-excited atomic-fluorescence spectrometry with electrothermal tube atomization.

    Science.gov (United States)

    Vera, J A; Leong, M B; Stevenson, C L; Petrucci, G; Winefordner, J D

    1989-12-01

    The performance of graphite-tube electrothermal atomizers is evaluated for laser-excited atomic-fluorescence spectrometry for several elements. Three pulsed laser systems are used to pump tunable dye lasers which subsequently are used to excite Pb, Ga, In, Fe, Ir, and Tl atoms in the hot graphite tube. The dye laser systems used are pumped by nitrogen, copper vapour and Nd:YAG lasers. Detection limits in the femtogram and subfemtogram range are typically obtained for all elements. A commercial graphite-tube furnace is important for the successful utilization of the laser-based method when the determination of trace elements is intended, especially when complicated matrices may be present.

  7. Advanced Spectral Library (ASTRAL): Atomic Fluorescence in Cool, Evolved Stars

    Science.gov (United States)

    Carpenter, Ken G.; Nielsen, Krister E.; Kober, Gladys V.; Rau, Gioia

    2018-01-01

    The "Advanced Spectral Library (ASTRAL) Project: Cool Stars" (PI = T. Ayres) collected a definitive set of representative, high-resolution (R~46,000 in the FUV up to ~1700 Å, R~30,000 for 1700-2150 Å, and R~114,000 >2150 Å) and high signal/noise (S/N>100) UV spectra of eight F-M evolved cool stars. These extremely high-quality STIS UV echelle spectra are available from the HST archive and from the Univ. of Colorado (http://casa.colorado.edu/~ayres/ASTRAL/) and will enable investigations of a broad range of problems -- stellar, interstellar, and beyond -- for many years. In this paper, we extend our study of the very rich emission-line spectra of the four evolved K-M stars in the sample, Beta Gem (K0 IIIb), Gamma Dra (K5 III), Gamma Cru (M3.4 III), and Alpha Ori (M2 Iab), to study the atomic fluorescence processes operating in their outer atmospheres. We summarize the pumping transitions and fluorescent line products known on the basis of previous work (e.g. Carpenter 1988, etc.) and newly identified in our current, on-going analysis of these extraordinary ASTRAL STIS spectra.

  8. [Atomic/ionic fluorescence in microwave plasma torch discharge with excitation of high current and microsecond pulsed hollow cathode lamp: Ca atomic/ionic fluorescence spectrometry].

    Science.gov (United States)

    Gong, Zhen-bin; Liang, Feng; Yang, Peng-yuan; Jin, Qin-han; Huang, Ben-li

    2002-02-01

    A system of atomic and ionic fluorescence spectrometry in microwave plasma torch (MPT) discharge excited by high current microsecond pulsed hollow cathode lamp (HCMP HCL) has been developed. The operation conditions for Ca atomic and ionic fluorescence spectrometry have been optimized. Compared with atomic fluorescence spectrometry (AFS) in argon microwave induced plasma (MIP) and MPT with the excitation of direct current and conventional pulsed HCL, the system with HCMP HCL excitation can improve AFS and ionic fluorescence spectrometry (IFS) detection limits in MPT atomizer and ionizer. Detection limits (3 sigma) with HCMP HCL-MPT-AFS/IFS are 10.1 ng.mL-1 for Ca I 422.7 nm, 14.6 ng.mL-1 for Ca II 393.4 nm, and 37.4 ng.mL-1 for Ca II 396.8 nm, respectively.

  9. Laser resonant ionization spectroscopy and laser-induced resonant fluorescence spectra of samarium atom

    International Nuclear Information System (INIS)

    Jin, Changtai

    1995-01-01

    We have measured new high-lying levels of Sm atom by two-colour resonant photoionisation spectroscopy; we have observed the isotope shifts of Sm atom by laser-induced resonant fluorescence spectroscopy; the lifetime of eight low-lying levels of Sm atom were measured by using pulsed laser-Boxcar technique in atomic beam.

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

    International Nuclear Information System (INIS)

    Marschner, Karel; Musil, Stanislav; Dědina, 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 NaBH 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 −1 and 1.0 ng l −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 −1

  11. 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}.

  12. Electrothermal atomization laser-excited atomic fluorescence spectroscopy for the determination of indium

    International Nuclear Information System (INIS)

    Aucelio, R.Q.; Smith, B.W.; Winefordner, J.D.

    1998-01-01

    A dye laser pumped by a high-repetition-rate copper vapor laser was used as the excitation source to determine indium at parts-per-trillion level by electrothermal atomization laser-excited atomic fluorescence spectrometry (ETA-LEAFS). A comparison was made between wall atomization, in pyrolytic and nonpyrolytic graphite tubes, and platform atomization. The influence of several chemical modifiers either in solution or precoated in the graphite tube was evaluated. The influence of several acids and NaOH in the analyte solution was also studied. Optimization of the analytical conditions was carried out to achieve the best signal-to-background ratio and consequently an absolute limit of detection of 1 fg. Some possible interferents of the method were evaluated. The method was evaluated by determining indium in blood, urine, soil, and urban dust samples. Recoveries between 99.17 and 109.17% are reported. A precision of 4.1% at the 10 ng g -1 level in water standards was achieved. copyright 1998 Society for Applied Spectroscopy

  13. Laser-induced fluorescence with an OPO system. Part II: direct determination of lead content in seawater by electrothermal atomization-laser-excited atomic fluorescence (ETA-LEAF).

    Science.gov (United States)

    Le Bihan, A; Lijour, Y; Giamarchi, P; Burel-Deschamps, L; Stephan, L

    2003-03-01

    Fluorescence was induced by coupling a laser with an optical parametric oscillator (OPO) to develop an analytical method for the direct determination of lead content, at ultra-trace level, in seawater by electrothermal atomization-laser-excited atomic fluorescence (ETA-LEAF). The optimization of atomization conditions, laser pulse energy, and mainly temporal parameters allowed us to reach a 3 fg detection limit (0.3 ng L(-1)) despite the low repetition rate of the device. The expected error on predicted concentrations of lead, at trace levels, in seawater was below 15%.

  14. High sensitivity detection of selenium by laser excited atomic fluorescence spectrometry using electrothermal atomization

    International Nuclear Information System (INIS)

    Heitmann, U.; Hese, A.; Schoknecht, G.; Gries, W.

    1995-01-01

    The high sensitivity detection of the trace element selenium is reported. The analytical method applied is Laser Excited Atomic Fluorescence Spectrometry using Electrothermal Atomization within a graphite furnace atomizer. For the production of tunable laser radiation in the VUV spectral region a laser system was developed which consists of two dye lasers pumped by a Nd:YAG laser. The laser radiations are subsequently frequency doubled and sum frequency mixed by nonlinear optical KDP or BBO crystals, respectively. The system works with a repetition rate of 20 Hz and provides output energies of up to 100 μJ in the VUV at a pulse duration of 5 ns. The analytical investigations were focused on the detection of selenium in aqueous solutions and samples of human whole blood. From measurements on aqueous standards detection limits of 1.5 ng/l for selenium were obtained, with corresponding absolute detected masses of only 15 fg. The linear dynamic range spanned six orders of magnitude and good precision was achieved. In case of human whole blood samples the recovery was found to be within the range of 96% to 104%. The determination of the selenium content yielded medians of [119.5 ± 17.3] μg/l for 200 frozen blood samples taken in 1988 and [109.1 ± 15.6] μg/l for 103 fresh blood samples. (author)

  15. Simultaneous determination of arsenic and antimony by hydride generation atomic fluorescence spectrometry with dielectric barrier discharge atomizer

    Energy Technology Data Exchange (ETDEWEB)

    Xing Zhi [Department of Chemistry, Key Laboratory for Atomic and Molecular Nanosciences of the Education Ministry, Tsinghua University, Beijing 100084 (China); Kuermaiti, Biekesailike [Department of Chemistry, Key Laboratory for Atomic and Molecular Nanosciences of the Education Ministry, Tsinghua University, Beijing 100084 (China); Products Quality Inspection Institute, Yili, Xinjiang 835000 (China); Wang Juan; Han Guojun; Zhang Sichun [Department of Chemistry, Key Laboratory for Atomic and Molecular Nanosciences of the Education Ministry, Tsinghua University, Beijing 100084 (China); Zhang Xinrong, E-mail: xrzhang@mail.tsinghua.edu.cn [Department of Chemistry, Key Laboratory for Atomic and Molecular Nanosciences of the Education Ministry, Tsinghua University, Beijing 100084 (China)

    2010-12-15

    Simultaneous determination of As and Sb by hydride generation atomic fluorescence spectrometry was developed with the dielectric barrier discharge plasma as the hydride atomizer. The low-temperature and atmospheric-pressure micro-plasma was generated in a quartz cylindrical configuration device, which was constructed by an axial internal electrode and an outer electrode surrounding outside of the tube. The optimization of the atomizer construction and parameters for hydride generation and fluorescence detection systems were carried out. Under the optimized conditions, the detection limits for As and Sb were 0.04 and 0.05 {mu}g L{sup -1}, respectively. In addition, the applicability of the present method was confirmed by the detection of As and Sb in reference materials of quartz sandstone (GBW07106) and argillaceous limestone (GBW07108). The present work provided a new approach to exploit the miniaturized hydride generation dielectric barrier discharge atomic fluorescence spectrometry system for simultaneous multi-element determination.

  16. Simultaneous determination of arsenic and antimony by hydride generation atomic fluorescence spectrometry with dielectric barrier discharge atomizer

    International Nuclear Information System (INIS)

    Xing Zhi; Kuermaiti, Biekesailike; Wang Juan; Han Guojun; Zhang Sichun; Zhang Xinrong

    2010-01-01

    Simultaneous determination of As and Sb by hydride generation atomic fluorescence spectrometry was developed with the dielectric barrier discharge plasma as the hydride atomizer. The low-temperature and atmospheric-pressure micro-plasma was generated in a quartz cylindrical configuration device, which was constructed by an axial internal electrode and an outer electrode surrounding outside of the tube. The optimization of the atomizer construction and parameters for hydride generation and fluorescence detection systems were carried out. Under the optimized conditions, the detection limits for As and Sb were 0.04 and 0.05 μg L -1 , respectively. In addition, the applicability of the present method was confirmed by the detection of As and Sb in reference materials of quartz sandstone (GBW07106) and argillaceous limestone (GBW07108). The present work provided a new approach to exploit the miniaturized hydride generation dielectric barrier discharge atomic fluorescence spectrometry system for simultaneous multi-element determination.

  17. Laser-induced fluorescence detection strategies for sodium atoms and compounds in high-pressure combustors

    Science.gov (United States)

    Weiland, Karen J. R.; Wise, Michael L.; Smith, Gregory P.

    1993-01-01

    A variety of laser-induced fluorescence schemes were examined experimentally in atmospheric pressure flames to determine their use for sodium atom and salt detection in high-pressure, optically thick environments. Collisional energy transfer plays a large role in fluorescence detection. Optimum sensitivity, at the parts in 10 exp 9 level for a single laser pulse, was obtained with the excitation of the 4p-3s transition at 330 nm and the detection of the 3d-3p fluorescence at 818 nm. Fluorescence loss processes, such as ionization and amplified spontaneous emission, were examined. A new laser-induced atomization/laser-induced fluorescence detection technique was demonstrated for NaOH and NaCl. A 248-nm excimer laser photodissociates the salt molecules present in the seeded flames prior to atom detection by laser-induced fluorescence.

  18. 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.

  19. Radio-isotopic apparatus for analyzing low atomic number elements by fluorescence

    International Nuclear Information System (INIS)

    Robert, Andre; Martinelli, Pierre; Daniel, Georges; Laflotte, Jean-Luc

    1969-10-01

    An apparatus is described for analyzing light elements of atomic number between 6 and 24 by X-fluorescence. The samples are excited by means of X or α isotopic sources. Various examples of analytical determinations are given. (author) [fr

  20. Resonance fluorescence spectra of a three-level atom driven by two strong laser fields

    International Nuclear Information System (INIS)

    Peng Jinsheng.

    1986-12-01

    The resonance fluorescence of a three-level atom interacted with two high-power laser fields is investigated in strong field approximation. The fluorescence distribution is obtained by means of the theory of dressing transformation. (author). 15 refs, 2 figs

  1. Single atom spectroscopy: Decreased scattering delocalization at high energy losses, effects of atomic movement and X-ray fluorescence yield.

    Science.gov (United States)

    Tizei, Luiz H G; Iizumi, Yoko; Okazaki, Toshiya; Nakanishi, Ryo; Kitaura, Ryo; Shinohara, Hisanori; Suenaga, Kazu

    2016-01-01

    Single atom localization and identification is crucial in understanding effects which depend on the specific local environment of atoms. In advanced nanometer scale materials, the characteristics of individual atoms may play an important role. Here, we describe spectroscopic experiments (electron energy loss spectroscopy, EELS, and Energy Dispersed X-ray spectroscopy, EDX) using a low voltage transmission electron microscope designed towards single atom analysis. For EELS, we discuss the advantages of using lower primary electron energy (30 keV and 60 keV) and higher energy losses (above 800 eV). The effect of atomic movement is considered. Finally, we discuss the possibility of using atomically resolved EELS and EDX data to measure the fluorescence yield for X-ray emission. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Single atom spectroscopy: Decreased scattering delocalization at high energy losses, effects of atomic movement and X-ray fluorescence yield

    International Nuclear Information System (INIS)

    Tizei, Luiz H.G.; Iizumi, Yoko; Okazaki, Toshiya; Nakanishi, Ryo; Kitaura, Ryo; Shinohara, Hisanori; Suenaga, Kazu

    2016-01-01

    Single atom localization and identification is crucial in understanding effects which depend on the specific local environment of atoms. In advanced nanometer scale materials, the characteristics of individual atoms may play an important role. Here, we describe spectroscopic experiments (electron energy loss spectroscopy, EELS, and Energy Dispersed X-ray spectroscopy, EDX) using a low voltage transmission electron microscope designed towards single atom analysis. For EELS, we discuss the advantages of using lower primary electron energy (30 keV and 60 keV) and higher energy losses (above 800 eV). The effect of atomic movement is considered. Finally, we discuss the possibility of using atomically resolved EELS and EDX data to measure the fluorescence yield for X-ray emission.

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

    NARCIS (Netherlands)

    Marinov, D.; Drag, C.; Blondel, C.; Guaitella, O.; Golda, J.; Klarenaar, B.L.M.; Engeln, R.A.H.; Schulz-von der Gathen, V.; Booth, J.-P.

    2016-01-01

    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

  4. Resonance fluorescence and quantum jumps in single atoms: Testing the randomness of quantum mechanics

    International Nuclear Information System (INIS)

    Erber, T.; Hammerling, P.; Hockney, G.; Porrati, M.; Putterman, S.; La Jolla Institute, La Jolla, California 92037; Department of Physics, University of California, Los Angeles, California 90024)

    1989-01-01

    When a single trapped 198 Hg + ion is illuminated by two lasers, each tuned to an approximate transition, the resulting fluorescence switches on and off in a series of pulses resembling a bistable telegraph. This intermittent fluorescence can also be obtained by optical pumping with a single laser. Quantum jumps between successive atomic levels may be traced directly with multiple-resonance fluorescence. Atomic transition rates and photon antibunching distributions can be inferred from the pulse statistics and compared with quantum theory. Stochastic tests also indicate that the quantum telegraphs are good random number generators. During periods when the fluorescence is switched off, the radiationless atomic currents that generate the telegraph signals can be adjusted by varying the laser illumination: if this coherent evolution of the wave functions is sustained over sufficiently long time intervals, novel interactive precision measurements, near the limits of the time-energy uncertainty relations, are possible. Copyright 1989 Academic Press, Inc

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

    Czech Academy of Sciences Publication Activity Database

    Marschner, Karel; Musil, Stanislav; Dědina, Jiří

    2015-01-01

    Roč. 109, JUL (2015), s. 16-23 ISSN 0584-8547 R&D Projects: GA ČR GA14-23532S Grant - others:GA AV ČR(CZ) M200311202 Institutional support: RVO:68081715 Keywords : hydride generation * arsenic * atomic fluorescence spectrometry Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.289, year: 2015

  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. Laser induced fluorescence spectroscopy in atomic beams of radioactive nuclides

    International Nuclear Information System (INIS)

    Rebel, H.; Schatz, G.

    1982-01-01

    Measurements of the resonant scattering of light from CW tunable dye lasers, by a well collimated atomic beam, enable hyperfine splittings and optical isotope shifts to be determined with high precision and high sensitivity. Recent off-line atomic beam experiments with minute samples, comprising measurements with stable and unstable Ba, Ca and Pb isotopes are reviewed. The experimental methods and the analysis of the data are discussed. Information on the variation of the rms charge radii and on electromagnetic moments of nuclei in long isotopic chains is presented. (orig.) [de

  8. An Experimental Study of the Fluorescence Spectrum of Cesium Atoms in the Presence of a Buffer Gas

    Science.gov (United States)

    Davydov, V. G.; Kulyasov, V. N.

    2018-01-01

    A direct experiment is performed to determine the quantum efficiency of a cesium fluorescence filter. The fluorescence spectra of cesium atoms are recorded under excitation of the upper states of the second resonance doublet with a Bell-Bloom cesium lamp. Introduction of different noble gases into the cell with cesium leads to the appearance of additional fluorescence photons. It is found that a fluorescence filter based on atomic cesium vapor with addition of helium in the working cell has the highest efficiency and response rate of all known fluorescence filters based on alkali-metal atomic vapors.

  9. Determination of heavy metals in polar snow and ice by laser-excited atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    Bolshov, M.A.; Boutron, C.F.

    1994-01-01

    The new laser-excited atomic fluorescence spectrometry technique offers unrivalled sensitivity for the determination of trace metals in a wide variety of samples. This has allowed the direct determination of Pb, Cd and Bi in Antarctic and Greenland snow and ice down to the sub pg/g level. (authors). 11 refs., 2 figs

  10. Laser-induced fluorescence of metal-atom impurities in a neutral beam

    International Nuclear Information System (INIS)

    Burrell, C.F.; Pyle, R.V.; Sabetimani, Z.; Schlachter, A.S.

    1984-10-01

    The need to limit impurities in fusion devices to low levels is well known. We have investigated, by the technique of laser-induced fluorescence, the concentration of heavy-metal atoms in a neutral beam caused by their evaporation from the hot filaments in a conventional high-current multifilament hydrogen-ion source

  11. Laser-induced fluorescence of se, as, and sb in an electrothermal atomizer.

    Science.gov (United States)

    Swart, D J; Ezer, M; Pacquette, H L; Simeonsson, J B

    1998-04-01

    Trace detection of Se, As, and Sb atoms has been performed by electrothermal atomization laser-induced fluorescence (ETA-LIF) approaches. Production of far-UV radiation necessary for excitation of As atoms at 193.696 nm and Se atoms at 196.026 nm was accomplished by stimulated Raman shifting (SRS) of the output of a frequency-doubled dye laser operating near 230 nm. Both wavelengths were obtained as second-order anti-Stokes shifts of the dye laser radiation and provided up to 10 μJ/pulse, which was shown through power dependence studies to be sufficient for saturation in the ETA. An excited-state direct line fluorescence approach using excitation at 206.279 nm was also investigated for the LIF detection of Se. High-sensitivity LIF of Sb atoms was accomplished using 206.833-nm excitation and detection at 259.805 nm. The accuracy of the ETA-LIF approaches was demonstrated by determining the As and Se content of aqueous reference samples. The limits of detection (absolute mass) were 200 fg by ground-state LIF and 150 fg by excited-state direct line fluorescence for Se, 200 fg for As, and 10 fg for Sb; these LODs compare favorably with results reported previously in the literature for ETA-LIF, GFAAS, and ICP-MS methods.

  12. Spatial discrimination against background with different optical systems for collection of fluorescence in laser-excited atomic fluorescence spectrometry with a graphite tube electrothermal atomizer.

    Science.gov (United States)

    Yuzefovsky, A I; Lonardo, R F; Michel, R G

    1995-07-01

    A single 90 degrees off-axis ellipsoidal mirror fragment was used in a dispersive detection system for electrothermal atomization laser-excited atomic fluorescence spectrometry. The performance of the new optical arrangement was compared with those of optical arrangements that employed a plane mirror in combination with biconvex or plano-convex lenses. All the optical arrangements collected fluorescence in a scheme called front surface illustration. BEAM-4, an optical ray tracing program, was used for calculations of spatial ray distributions and optical collection efficiency for the various optical configurations. Experimentally, the best collection efficiency was obtained by use of the ellipsoidal mirror, in qualitative agreement with simulations done by use of the BEAM-4 software. The best detection limit for cobalt with the new optical arrangement was 20 fg, which was a factor of 5 better than that obtained with conventional optical arrangements with otherwise the same instrumentation. The signal-to-background ratio and the fluorescence collection efficiency were also studied as a function of position of the optical components for the various optical arrangements. For both cobalt and phosphorus, the signal-to-background ratio with the new optical arrangement remained stable within 10-20% during +/- 8 mm shifts in the position of the detection system from the focal plane of the optics. Overall, the new optical arrangement offered high collection efficiency, excellent sensitivity, and facile optical alignment due to efficient spatial separation between the fluorescence signal and the background radiation. The advantages of the new optical arrangement were particularly important during measurements in the presence of high levels of blackbody radiation.

  13. Resonance fluorescence spectra of three-level atoms in a squeezed vacuum

    International Nuclear Information System (INIS)

    Ferguson, M.R.; Ficek, Z.; Dalton, B.J.

    1996-01-01

    The fluorescence field from one of the two allowed transitions in a three-level atom can sense squeezed fluctuations of a vacuum field coupled to the other transition. We examine the fluorescence spectra of strongly driven three-level atoms in Λ, V, and cascade configurations in which one of the two one-photon transitions is coupled to a finite-bandwidth squeezed vacuum field, when the bandwidth is much smaller than the difference in the atomic transition frequencies, though much larger than atomic decay rates and Rabi frequencies of the driving fields. The driving fields are on one-photon resonance, and the squeezed vacuum field is generated by a degenerate parameter oscillator. Details are only given for the Λ configuration. The extension to the V and cascade configurations is straightforward. We find that in all configurations the fluorescence spectra of the transition not coupled to the squeezed vacuum field are composed of five lines, one central and two pairs of sidebands, with intensities and widths strongly influenced by the squeezed vacuum field. However, only the central component and the outer sidebands exhibit a dependence on the squeezing phase. We also examine the fluorescence spectrum for the cascade configuration with a squeezed vacuum field on resonance with the two-photon transition between the ground and the most excited states and now generated by a nondegenerate parametric oscillator. In this case, where the squeezed vacuum field can be made coupled to both transitions, all spectral lines depend on the squeezing phase. The spectral features are explained in terms of the dressed-atom model of the system. We show that the coherent mixing of the atomic states by the strong driving fields modifies transition rates between the dressed states, which results in the selective phase dependence of the spectral features. copyright 1996 The American Physical Society

  14. Laser-excited atomic fluorescence spectrometry in a pressure-controlled electrothermal atomizer.

    Science.gov (United States)

    Lonardo, R F; Yuzefovsky, A I; Irwin, R L; Michel, R G

    1996-02-01

    A theoretical model was developed to describe the loss of analyte atoms in graphite furnaces during atomization. The model was based on two functions, one that described the supply of analyte by vaporization, and another that described the removal of the analyte by diffusion. Variation in working pressure was shown to affect the competition between these two processes. Optimal atomization efficiency was predicted to occur at a pressure where the supply of the analyte was maximized, and gas phase interactions between the analyte and matrix were minimized. Experiments to test the model included the direct determination of phosphorus and tellurium in nickel alloys and of cobalt in glass. In all cases, reduction in working pressure from atmospheric pressure to 7 Pa decreased sensitivity by 2 orders of magnitude, but improved temporal peak shape. For the atomization of tellurium directly from a solid nickel alloy, and the atomization of cobalt from an aqueous solution, no change in sensitivity was observed as the working pressure was reduced from atmospheric pressure to approximately 70 kPa. If a reduction in working pressure affected only the diffusion of the analyte, poorer sensitivity should have been obtained. Only a commensurate increase in analyte vaporization could account for maintained sensitivity at lower working pressures. Overall, analyte vaporization was not dramatically improved at reduced working pressures, and maximum atomization efficiency was found to occur near atmospheric pressure.

  15. Evaluation of a hydride generation-atomic fluorescence system for the determination of arsenic using a dielectric barrier discharge atomizer

    International Nuclear Information System (INIS)

    Zhu Zhenli; Liu Jixin; Zhang Sichun; Na Xing; Zhang Xinrong

    2008-01-01

    A new atomizer based on atmospheric pressure dielectric barrier discharge (DBD) plasma was specially designed for atomic fluorescence spectrometry (AFS) in order to be applied to the measurement of arsenic. The characteristics of the DBD atomizer and the effects of different parameters (power, discharge gas, gas flow rate, and KBH 4 concentration) were discussed in the paper. The DBD atomizer shows the following features: (1) low operation temperature (between 44 and 70 deg. C, depending on the operation conditions); (2) low power consumption; (3) operation at atmospheric pressure. The detection limit of As(III) using hydride generation (HG) with the proposed DBD-AFS was 0.04 μg L -1 . The analytical results obtained by the present method for total arsenic in reference materials, orchard leaves (SRM 1571) and water samples GBW(E) 080390, agree well with the certified values. The present HG-DBD-AFS is more sensitive and reliable for the determination of arsenic. It is a very promising technique allowing for field arsenic analysis based on atomic spectrometry

  16. Determination of mercury in microwave-digested soil by laser-excited atomic fluorescence spectrometry with electrothermal atomization.

    Science.gov (United States)

    Pagano, S T; Smith, B W; Winefordner, J D

    1994-12-01

    A sample digestion procedure was developed which employs microwave heating of soil and sediment in concentrated nitric acid in a high-pressure closed vessel. Complete dissolution of mercury into the sample solution occurs within 5 min at 59 W/vessel without loss of analyte through overpressurization. Laser-excited atomic fluorescence spectrometry with electrothermal atomization (LEAFS-ETA) was used as the detection method. The scheme uses a two-step excitation, with lambda(1) = 253.7 nm and lambda(2) = 435.8 nm. Direct line fluorescence was measured at 546.2 nm. The absolute instrumental limit of detection was 14 fg; 1.4 pg/ml with a 10 mul sample injection. The recoveries of mercury in two spiked samples were 94 and 98%. The SRM 8406 (Mercury in River Sediment) was digested and analyzed for mercury, and the results (58.4 +/- 1.8 ng/g) agreed well with the reference value of 60 ng/g. The results obtained by LEAFS-ETA with microwave sample digestion are in good agreement with those found by cold vapor atomic absorption spectrometry with EPA Series Method 245.5 sample digestion, which is one of the most commonly used methods for the determination of mercury in soil.

  17. Imaging time-resolved electrothermal atomization laser-excited atomic fluorescence spectrometry for determination of mercury in seawater.

    Science.gov (United States)

    Le Bihan, Alain; Cabon, Jean-Yves; Deschamps, Laure; Giamarchi, Philippe

    2011-06-15

    In this study, direct determination of mercury at the nanogram per liter level in the complex seawater matrix by imaging time-resolved electrothermal atomization laser-excited atomic fluorescence spectrometry (ITR-ETA-LEAFS) is described. In the case of mercury, the use of a nonresonant line for fluorescence detection with only one laser excitation is not possible. For measurements at the 253.652 nm resonant line, scattering phenomena have been minimized by eliminating the simultaneous vaporization of salts and by using temporal resolution and the imaging mode of the camera. Electrothermal conditions (0.1 M oxalic acid as matrix modifier, low atomization temperature) have been optimized in order to suppress chemical interferences and to obtain a good separation of specific signal and seawater background signal. For ETA-LEAFS, a specific response has been obtained for Hg with the use of time resolution. Moreover, an important improvement of the detection limit has been obtained by selecting, from the furnace image, pixels collecting the lowest number of scattered photons. Using optimal experimental conditions, a detection limit of 10 ng L(-1) for 10 μL of sample, close to the lowest concentration level of total Hg in the open ocean, has been obtained.

  18. Determination of iron in seawater by electrothermal atomic absorption spectrometry and atomic fluorescence spectrometry: A comparative study

    International Nuclear Information System (INIS)

    Cabon, J.Y.; Giamarchi, P.; Le Bihan, A.

    2010-01-01

    Two methods available for direct determination of total Fe in seawater at low concentration level have been examined: electrothermal atomization atomic absorption spectrometry (ETAAS) and electrothermal atomization laser excited atomic fluorescence spectrometry (ETA-LEAFS). In a first part, we have optimized experimental conditions of ETAAS (electrothermal program, matrix chemical modification) for the determination of Fe in seawater by minimizing the chemical interference effects and the magnitude of the simultaneous background absorption signal. By using the best experimental conditions, a detection limit of 80 ng L -1 (20 μL, 3σ) for total Fe concentration was obtained by ETAAS. Using similar experimental conditions (electrothermal program, chemical modification), we have optimized experimental conditions for the determination of Fe by LEAFS. The selected experimental conditions for ETA-LEAFS: excitation wavelength (296.69 nm), noise attenuation and adequate background correction led to a detection limit (3σ) of 3 ng L -1 (i.e. 54 pM) for total Fe concentration with the use a 20 μL seawater sample. For the two methods, concentration values obtained for the analysis of Fe in a NASS-5 (0.2 μg L -1 ) seawater sample were in good agreement with the certified values.

  19. Determination of iron in seawater by electrothermal atomic absorption spectrometry and atomic fluorescence spectrometry: a comparative study.

    Science.gov (United States)

    Cabon, J Y; Giamarchi, P; Le Bihan, A

    2010-04-07

    Two methods available for direct determination of total Fe in seawater at low concentration level have been examined: electrothermal atomization atomic absorption spectrometry (ETAAS) and electrothermal atomization laser excited atomic fluorescence spectrometry (ETA-LEAFS). In a first part, we have optimized experimental conditions of ETAAS (electrothermal program, matrix chemical modification) for the determination of Fe in seawater by minimizing the chemical interference effects and the magnitude of the simultaneous background absorption signal. By using the best experimental conditions, a detection limit of 80 ng L(-1) (20 microL, 3sigma) for total Fe concentration was obtained by ETAAS. Using similar experimental conditions (electrothermal program, chemical modification), we have optimized experimental conditions for the determination of Fe by LEAFS. The selected experimental conditions for ETA-LEAFS: excitation wavelength (296.69 nm), noise attenuation and adequate background correction led to a detection limit (3sigma) of 3 ng L(-1) (i.e. 54 pM) for total Fe concentration with the use a 20 microL seawater sample. For the two methods, concentration values obtained for the analysis of Fe in a NASS-5 (0.2 microg L(-1)) seawater sample were in good agreement with the certified values. Copyright 2010 Elsevier B.V. All rights reserved.

  20. 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.

  1. Development of an electrothermal atomization laser-excited atomic fluorescence spectrometry procedure for direct measurements of arsenic in diluted serum.

    Science.gov (United States)

    Swart, D J; Simeonsson, J B

    1999-11-01

    A procedure for the direct determination of arsenic in diluted serum by electrothermal atomization laser-excited atomic fluorescence spectrometry (ETA-LEAFS) is reported. Laser radiation needed to excite As at 193.696 and 197.197 nm is generated as the second anti-Stokes stimulated Raman scattering output of a frequency-doubled dye laser operating near 230.5 and 235.5 nm, respectively. Two different LEAFS schemes have been utilized and provide limits of detection of 200-300 fg for As in aqueous standards. When measurements of serum samples diluted 1:10 with deionized water are performed, a stable background signal is observed that can be accounted for by taking measurements with the laser tuned off-wavelength. No As is detected in any of the bovine or human serum samples analyzed. Measurements of 100 pg/mL standard additions of As to a diluted bovine serum sample utilizing either inorganic or organic As species demonstrate a linear relationship of the fluorescence signal to As spike concentration, but exhibit a sensitivity of approximately half that observed in pure aqueous standards. The limit of detection for As in 1:10 diluted serum samples is 65 pg/mL or 650 fg absolute mass, which corresponds to 0.65 ng/mL As in undiluted serum. To our knowledge, the ETA-LEAFS procedure is currently the only one capable of directly measuring As in diluted serum at these levels.

  2. Two-photon laser-induced fluorescence studies of HS radicals, DS radicals, and I atoms

    Energy Technology Data Exchange (ETDEWEB)

    Tiee, J J; Ferris, M J; Loge, G W; Wampler, F B

    1983-04-15

    A two-photon laser-induced excitation and fluorescence technique has been used to study the A /sup 2/..sigma../sup +/ - X/sup 2/PI transition of HS and DS radicals and various high-lying /sup 4/P/sup 0/, /sup 2/D/sup 0/, and /sup 4/D/sup 0/ states of the I atom. The two-photon excitation cross sections and detection sensitivity are discussed. 13 references, 5 figures.

  3. Fluorescence measurement of atomic oxygen concentration in a dielectric barrier discharge

    Science.gov (United States)

    Dvořák, P.; Mrkvičková, M.; Obrusník, A.; Kratzer, J.; Dědina, J.; Procházka, V.

    2017-06-01

    Concentration of atomic oxygen was measured in a volume dielectric barrier discharge (DBD) ignited in mixtures of Ar + O2(+ H2) at atmospheric pressure. Two-photon absorption laser induced fluorescence (TALIF) of atomic oxygen was used and this method was calibrated by TALIF of Xe in a mixture of argon and a trace of xenon. The calibration was performed at atmospheric pressure and it was shown that quenching by three-body collisions has negligible effect on the life time of excited Xe atoms. The concentration of atomic oxygen in the DBD was around 1021 m-3 and it was stable during the whole discharge period. The concentration did not depend much on the electric power delivered to the discharge provided that the power was sufficiently high so that the visible discharge filled the whole reactor volume. Both the addition of hydrogen or replacing of argon by helium led to a significant decrease of atomic oxygen concentration. The TALIF measurements of O concentration levels in the DBD plasma performed in this work are made use of e.g. in the field analytical chemistry. The results contribute to understanding the processes of analyte hydride preconcentration and subsequent atomization in the field of trace element analysis where DBD plasma atomizers are employed.

  4. Simultaneous differential spinning disk fluorescence optical sectioning microscopy and nanomechanical mapping atomic force microscopy

    International Nuclear Information System (INIS)

    Miranda, Adelaide; De Beule, Pieter A. A.; Martins, Marco

    2015-01-01

    Combined microscopy techniques offer the life science research community a powerful tool to investigate complex biological systems and their interactions. Here, we present a new combined microscopy platform based on fluorescence optical sectioning microscopy through aperture correlation microscopy with a Differential Spinning Disk (DSD) and nanomechanical mapping with an Atomic Force Microscope (AFM). The illumination scheme of the DSD microscope unit, contrary to standard single or multi-point confocal microscopes, provides a time-independent illumination of the AFM cantilever. This enables a distortion-free simultaneous operation of fluorescence optical sectioning microscopy and atomic force microscopy with standard probes. In this context, we discuss sample heating due to AFM cantilever illumination with fluorescence excitation light. Integration of a DSD fluorescence optical sectioning unit with an AFM platform requires mitigation of mechanical noise transfer of the spinning disk. We identify and present two solutions to almost annul this noise in the AFM measurement process. The new combined microscopy platform is applied to the characterization of a DOPC/DOPS (4:1) lipid structures labelled with a lipophilic cationic indocarbocyanine dye deposited on a mica substrate

  5. Simultaneous differential spinning disk fluorescence optical sectioning microscopy and nanomechanical mapping atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Adelaide; De Beule, Pieter A. A., E-mail: pieter.de-beule@inl.int [Applied Nano-Optics Laboratory, International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, s/n, 4715-330 Braga (Portugal); Martins, Marco [Nano-ICs Group, International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga, s/n, 4715-330 Braga (Portugal)

    2015-09-15

    Combined microscopy techniques offer the life science research community a powerful tool to investigate complex biological systems and their interactions. Here, we present a new combined microscopy platform based on fluorescence optical sectioning microscopy through aperture correlation microscopy with a Differential Spinning Disk (DSD) and nanomechanical mapping with an Atomic Force Microscope (AFM). The illumination scheme of the DSD microscope unit, contrary to standard single or multi-point confocal microscopes, provides a time-independent illumination of the AFM cantilever. This enables a distortion-free simultaneous operation of fluorescence optical sectioning microscopy and atomic force microscopy with standard probes. In this context, we discuss sample heating due to AFM cantilever illumination with fluorescence excitation light. Integration of a DSD fluorescence optical sectioning unit with an AFM platform requires mitigation of mechanical noise transfer of the spinning disk. We identify and present two solutions to almost annul this noise in the AFM measurement process. The new combined microscopy platform is applied to the characterization of a DOPC/DOPS (4:1) lipid structures labelled with a lipophilic cationic indocarbocyanine dye deposited on a mica substrate.

  6. [Atomic/ionic fluorescence in microwave plasma torch discharge excited by high current microsecond pulsed hollow cathode lamp-europium atomic/ionic fluorescence spectrometry].

    Science.gov (United States)

    Gong, Z; Liang, F; Yang, P; Jin, Q; Huang, B

    1999-06-01

    Eu atomic and ionic fluorescence spectrometry in microwave plasma torch discharge excited by high current microsecond pulsed hollow cathode lamp (HCMP HCL-MPT AFS/IFS) was studied. Operating conditions were optimized. The best detection limits for AFS and IFS obtained with a desolvated ultrasonic nebulization system were 42.0 ng/mL for Eu I 462.7 nm and 21.8 ng/mL for Eu II 381.97 nm, respectively, both were better than those given by the instruction manual of a Baird ICP AFS-2000 spectrometer using pneumatic concentric nebulizer with desolvation for AFS, but were significantly higher than those obtained by using the Baird spectrometer with a mini-monochromator and a ultrasonic nebulzer system.

  7. Concentration of atomic hydrogen in a dielectric barrier discharge measured by two-photon absorption fluorescence

    Science.gov (United States)

    Dvořák, P.; Talába, M.; Obrusník, A.; Kratzer, J.; Dědina, J.

    2017-08-01

    Two-photon absorption laser-induced fluorescence (TALIF) was utilized for measuring the concentration of atomic hydrogen in a volume dielectric barrier discharge (DBD) ignited in mixtures of Ar, H2 and O2 at atmospheric pressure. The method was calibrated by TALIF of krypton diluted in argon at atmospheric pressure, proving that three-body collisions had a negligible effect on quenching of excited krypton atoms. The diagnostic study was complemented with a 3D numerical model of the gas flow and a zero-dimensional model of the chemistry in order to better understand the reaction kinetics and identify the key pathways leading to the production and destruction of atomic hydrogen. It was determined that the density of atomic hydrogen in Ar-H2 mixtures was in the order of 1021 m-3 and decreased when oxygen was added into the gas mixture. Spatially resolved measurements and simulations revealed a sharply bordered region with low atomic hydrogen concentration when oxygen was added to the gas mixture. At substoichiometric oxygen/hydrogen ratios, this H-poor region is confined to an area close to the gas inlet and it is shown that the size of this region is not only influenced by the chemistry but also by the gas flow patterns. Experimentally, it was observed that a decrease in H2 concentration in the feeding Ar-H2 mixture led to an increase in H production in the DBD.

  8. Behaviour of atomic oxygen in a pulsed dielectric barrier discharge measured by laser-induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Ryo [High Temperature Plasma Center, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 227-8568 (Japan); Yamashita, Youta [Department of Electrical Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan); Takezawa, Kei [Department of Electrical Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan); Oda, Tetsuji [Department of Electrical Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan)

    2005-08-21

    Atomic oxygen is measured in a pulsed dielectric barrier discharge (DBD) using two-photon absorption laser-induced fluorescence (TALIF). The ground-level atomic oxygen is excited to the 3p {sup 3}P state by two-photon absorption at 226 nm. Negative (-40 kV) or positive (+30 kV) pulsed DBD occurs in an O{sub 2}-N{sub 2} mixture at atmospheric pressure. The pulse width of the DBD current is approximately 50 ns. The TALIF experiment shows that the decay rate of atomic oxygen increases linearly with O{sub 2} concentration. This result proves that atomic oxygen decays mainly by the third-body reaction, O + O{sub 2} + M {yields} O{sub 3} + M. The rate coefficient of the third-body reaction is estimated to be 2.2 x 10{sup -34} cm{sup 6} s{sup -1} in the negative DBD and 0.89 x 10{sup -34} cm{sup 6} s{sup -1} in the positive DBD. It is shown that the decay rate of atomic oxygen increases linearly with humidity. This can explain the well-known fact that ozone production in DBD is suppressed by increasing humidity.

  9. Behaviour of atomic oxygen in a pulsed dielectric barrier discharge measured by laser-induced fluorescence

    International Nuclear Information System (INIS)

    Ono, Ryo; Yamashita, Youta; Takezawa, Kei; Oda, Tetsuji

    2005-01-01

    Atomic oxygen is measured in a pulsed dielectric barrier discharge (DBD) using two-photon absorption laser-induced fluorescence (TALIF). The ground-level atomic oxygen is excited to the 3p 3 P state by two-photon absorption at 226 nm. Negative (-40 kV) or positive (+30 kV) pulsed DBD occurs in an O 2 -N 2 mixture at atmospheric pressure. The pulse width of the DBD current is approximately 50 ns. The TALIF experiment shows that the decay rate of atomic oxygen increases linearly with O 2 concentration. This result proves that atomic oxygen decays mainly by the third-body reaction, O + O 2 + M → O 3 + M. The rate coefficient of the third-body reaction is estimated to be 2.2 x 10 -34 cm 6 s -1 in the negative DBD and 0.89 x 10 -34 cm 6 s -1 in the positive DBD. It is shown that the decay rate of atomic oxygen increases linearly with humidity. This can explain the well-known fact that ozone production in DBD is suppressed by increasing humidity

  10. Supersonic pulsed free-jet of atoms and molecules of refractory metals: laser induced fluorescence spectroscopic studies on zirconium atoms and zirconium oxide molecules

    International Nuclear Information System (INIS)

    Nakhale, S.G.

    2004-11-01

    The experimental setup for generating supersonic pulsed free-jet containing atoms and molecules of refractory nature has been built. The technique of laser vaporization in conjunction with supersonic cooling is used to generate these species. The cooled atoms and molecules in supersonic free-jet are probed by laser induced fluorescence spectroscopy. In particular, the technique has been used to perform low-resolution laser induced fluorescence spectroscopy, limited by laser linewidth, on cold Zr atoms and ZrO molecules. The translational temperatures of ∼ 26.5 K and the rotational temperatures of ∼ 81 K have been achieved. It is possible to achieve the Doppler width of few tens of MHz allowing it to perform high-resolution spectroscopy on these atomic and molecular species. Also because of low rotational temperature of molecules the spectral congestion is greatly reduced. In general, this technique can be applied to perform spectroscopy on atoms and molecules of refractory nature. (author)

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

    International Nuclear Information System (INIS)

    Arp, U.

    1996-01-01

    Argon L 2.3 -M 2.3 M 2.3 Auger-electron spectra were measured in coincidence with Kα 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

  12. X-ray fluorescence holography and multiple-energy x-ray holography: A critical comparison of atomic images

    International Nuclear Information System (INIS)

    Len, P.M.; Gog, T.; Fadley, C.S.; Materlik, G.

    1997-01-01

    We compare x-ray fluorescence holography (XFH) and multiple-energy x-ray holography (MEXH), two techniques that have recently been used to obtain experimental three-dimensional atomic images. For single-energy holograms, these methods are equivalent by virtue of the optical reciprocity theorem. However, XFH can only record holographic information at the characteristic fluorescence energies of the emitting species, while MEXH can record holographic information at any energy above the fluorescent edge of the emitter, thus enabling the suppression of real-twin overlaps and other aberrations and artifacts in atomic images. copyright 1997 The American Physical Society

  13. Design and development of high-resolution atomic beam fluorescence spectroscopy facility for isotope shift and hyperfine structure measurements

    International Nuclear Information System (INIS)

    Acharyulu, G.V.S.G.; Sankari, M.; Kiran Kumar, P.V.; Suryanarayana, M.V.

    2012-01-01

    A high-resolution atomic beam fluorescence spectroscopy facility for the determination of isotope shifts and hyperfine structure in atomic species has been designed and developed. A resistively heated graphite tube atomic beam source was designed, tested and integrated into a compact interaction chamber for atomic beam fluorescence experiments. The design of the laser-atom interaction chamber and the source has been modified in a phased manner so as to achieve sub-Doppler resolution. The system has been used to record the hyperfine spectrum of the D2 transitions of Rb and K isotopes. The spectral resolution achieved is ∼ 26 MHz and is adequate to carry out high resolution measurement of isotope shifts and hyperfine structure of various atomic species. The other major advantage of the source is that it requires very small amounts of sample for achieving very good signal to noise ratio. (author)

  14. Fluorescent atom coincidence spectroscopy of extremely neutron-deficient barium isotopes

    International Nuclear Information System (INIS)

    Wells, S.A.; Evans, D.E.; Griffith, J.A.R.; Eastham, D.A.; Groves, J.; Smith, J.R.H.; Tolfree, D.W.L.; Warner, D.D.; Billowes, J.; Grant, I.S.; Walker, P.M.

    1988-01-01

    Fluorescent atom coincidence spectroscopy (FACS) has been used to measure the nuclear mean square radii and moments of the extremely neutron-deficient isotopes 120-124 Ba. At N=65 an abrupt change in nuclear mean square charge radii is observed which can be understood in terms of the occupation of the spin-orbit partner g 7/2 5/2[413] neutron and g 9/2 9/2[404] proton orbitals and the consequent enhancement of the n-p interaction. (orig.)

  15. Observation of self-assembled fluorescent beads by scanning near-field optical microscopy and atomic force microscopy

    International Nuclear Information System (INIS)

    Oh, Y.J.; Jo, W.; Kim, Min-Gon; Kyu Park, Hyun; Hyun Chung, Bong

    2006-01-01

    Optical response and topography of fluorescent latex beads both on flat self-assembled monolayer and on a micron-patterned surface with poly(dimethylsiloxane) are studied. Scanning near-field optical microscopy and atomic force microscopy were utilized together for detecting fluorescence and imaging topography of the patterned latex beads, respectively. As a result, the micro-patterned latex beads where a specific chemical binding occurred show a strong signal, whereas no signals are observed in the case of nonspecific binding. With fluorescein isothiocyanate (FITC), it is convenient to measure fluorescence signal from the patterned beads allowing us to monitor the small balls of fluorescent latex

  16. Advances in low atomic number element analysis by wavelength dispersive x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Vrebos, B.

    1996-01-01

    Traditionally, the analysis of low atomic number has been a chal1enging task for wavelength dispersive x-ray fluorescence spectrometry. Among the most important factors influencing analysis of the low atomic number elements (from Z=11 downwards) are the fluorescence yield, absorption and the dispersion. The effect of each of these factors on the overall performance will be illustrated. The long wavelengths involved (longer than I nm) used to pose severe problems concerning the monochromator used. Early instruments relied on lead stearate or Blodgett Langmuir soap films for the diffraction of the characteristic radiation. Nowadays, synthetic multilayers are commonly used. The performance of these multilayers is determined by the reflectivity, the resolution and the absorption of the characteristic radiation to be diffracted. These parameters can be optimised by adequately selecting the composition of the materials involved. The sensitivity of the modem instruments is sufficient to allow quantitative analysis. However, this aspect of WDS XRF is still met with considerable scepticism. Examples of quantitative analysis will be given to illustrate the current capability

  17. Multipumping flow system for improving hydride generation atomic fluorescence spectrometric determinations

    International Nuclear Information System (INIS)

    Lopez-Garcia, Ignacio; Ruiz-Alcaraz, Irene; Hernandez-Cordoba, Manuel

    2006-01-01

    The advantages of using membrane micropumps rather than peristaltic pumps to introduce both sample and reagent solutions for hydride generation atomic fluorescence spectrometry are discussed. Arsenic was used as a test analyte to check the performance of the proposed manifold. Sample and reagent consumption was reduced 8-9 fold compared with continuous mode measurements made with peristaltic pumps, with no deterioration in sensitivity. The calibration graph was linear in the 0.05 to 2.5 μg l -1 As range using peak area as the analytical signal and maximum gain in the detector setting. A limit of detection (3σ) of 0.02 μg l -1 and relative standard deviation values close to 2% for 10 independent measurements of a 1 μg l -1 As solution were obtained. The sampling frequency increased from 45 to 102 h -1 with the subsequent saving in carrier gas used and reduction in wastes generated. The instrumental modification, which could be used for other elements currently determined by atomic fluorescence spectrometry, will permit hydride generators of more reduced dimensions to be constructed

  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

    Czech Academy of Sciences Publication Activity Database

    Musil, Stanislav; Matoušek, Tomáš; Currier, J. M.; Stýblo, M.; Dědina, Jiří

    2014-01-01

    Roč. 86, č. 20 (2014), s. 10422-10428 ISSN 0003-2700 R&D Projects: GA ČR GA14-23532S; GA MŠk LH12040 Institutional support: RVO:68081715 Keywords : speciation analysis of arsenic * selective hydride generation * flame-in-gas-shield atomizer * cryotrapping-atomic fluorescence spectrometry Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 5.636, year: 2014

  19. Correlated Fluorescence-Atomic Force Microscopy Studies of the Clathrin Mediated Endocytosis in SKMEL Cells

    Science.gov (United States)

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

    Clathrin-mediated endocytosis 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. 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 fluorescent fusion proteins (actin filaments labeled with green phalloidin-antibody and clathrin coated vesicles with the fusion protein Tq2) in SKMEL (Human Melanoma) cells. Results from our work are compared against dynamical polarized total internal fluorescence (TIRF), super-resolution photo-activated localization microscopy (PALM) and transmission electron microscopy (TEM) to draw conclusions regarding the prominent model of vesicle formation in clathrin-mediated endocytosis. Funding provided by NSF MPS/DMR/BMAT award # 1206908.

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

    International Nuclear Information System (INIS)

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

    2011-01-01

    A method for a direct measurement of X-ray projections of the atomic structure is described. Projections of the atomic structure around Nb atoms in a LiNbO 3 single crystal were obtained from a white-beam X-ray absorption anisotropy pattern detected using Nb K fluorescence. Projections of the atomic structure around Nb atoms in a LiNbO 3 single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using Nb K fluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples

  1. Evaluation of a tungsten coil atomization-laser-induced fluorescence detection approach for trace elemental analysis

    International Nuclear Information System (INIS)

    Ezer, Muhsin; Elwood, Seth A.; Jones, Bradley T.; Simeonsson, Josef B.

    2006-01-01

    The analytical utility of a tungsten (W)-coil atomization-laser-induced fluorescence (LIF) approach has been evaluated for trace level measurements of elemental chromium (Cr), arsenic (As), selenium (Se), antimony (Sb), lead (Pb), tin (Sn), copper (Cu), thallium (Tl), indium (In), cadmium (Cd), zinc (Zn) and mercury (Hg). Measurements of As, Cr, In, Se, Sb, Pb, Tl, and Sn were performed by laser-induced fluorescence using a single dye laser operating near 460 nm whose output was converted by frequency doubling and stimulated Raman scattering to wavelengths ranging from 196 to 286 nm for atomic excitation. Absolute limits of detection (LODs) of 1, 0.3, 0.3, 0.2, 1, 6, 1, 0.2 and 0.8 pg and concentration LODs of 100, 30, 30, 20, 100, 600, 100, 20, and 80 pg/mL were achieved for As, Se, Sb, Sn, In, Cu, Cr, Pb and Tl, respectively. Determinations of Hg, Pb, Zn and Cd were performed using two-color excitation approaches and resulted in absolute LODs of 2, 30, 5 and 0.6 pg, respectively, and concentration LODs of 200, 3000, 500 and 60 pg/mL, respectively. The sensitivities achieved by the W-coil LIF approaches compare well with those reported by W-coil atomic absorption spectrometry, graphite furnace atomic absorption spectrometry, and graphite furnace electrothermal atomization-LIF approaches. The accuracy of the approach was verified through the analysis of a multielement reference solution containing Sb, Pb and Tl which each had certified performance acceptance limits of 19.6-20.4 μg/mL. The determined concentrations were 20.05 ± 2.60, 20.70 ± 2.27 and 20.60 ± 2.46 μg/mL, for Sb, Pb and Tl, respectively. The results demonstrate that W-coil LIF provides good analytical performance for trace analyses due to its high sensitivity, linearity, and capability to measure multiple elements using a single tunable laser and suggest that the development of portable W-coil LIF instrumentation using compact, solid-state lasers is feasible

  2. Evaluation of a tungsten coil atomization-laser-induced fluorescence detection approach for trace elemental analysis.

    Science.gov (United States)

    Ezer, Muhsin; Elwood, Seth A; Jones, Bradley T; Simeonsson, Josef B

    2006-06-30

    The analytical utility of a tungsten (W)-coil atomization-laser-induced fluorescence (LIF) approach has been evaluated for trace level measurements of elemental chromium (Cr), arsenic (As), selenium (Se), antimony (Sb), lead (Pb), tin (Sn), copper (Cu), thallium (Tl), indium (In), cadmium (Cd), zinc (Zn) and mercury (Hg). Measurements of As, Cr, In, Se, Sb, Pb, Tl, and Sn were performed by laser-induced fluorescence using a single dye laser operating near 460 nm whose output was converted by frequency doubling and stimulated Raman scattering to wavelengths ranging from 196 to 286 nm for atomic excitation. Absolute limits of detection (LODs) of 1, 0.3, 0.3, 0.2, 1, 6, 1, 0.2 and 0.8 pg and concentration LODs of 100, 30, 30, 20, 100, 600, 100, 20, and 80 pg/mL were achieved for As, Se, Sb, Sn, In, Cu, Cr, Pb and Tl, respectively. Determinations of Hg, Pb, Zn and Cd were performed using two-color excitation approaches and resulted in absolute LODs of 2, 30, 5 and 0.6 pg, respectively, and concentration LODs of 200, 3000, 500 and 60 pg/mL, respectively. The sensitivities achieved by the W-coil LIF approaches compare well with those reported by W-coil atomic absorption spectrometry, graphite furnace atomic absorption spectrometry, and graphite furnace electrothermal atomization-LIF approaches. The accuracy of the approach was verified through the analysis of a multielement reference solution containing Sb, Pb and Tl which each had certified performance acceptance limits of 19.6-20.4 microg/mL. The determined concentrations were 20.05+/-2.60, 20.70+/-2.27 and 20.60+/-2.46 microg/mL, for Sb, Pb and Tl, respectively. The results demonstrate that W-coil LIF provides good analytical performance for trace analyses due to its high sensitivity, linearity, and capability to measure multiple elements using a single tunable laser and suggest that the development of portable W-coil LIF instrumentation using compact, solid-state lasers is feasible.

  3. X-ray fluorescence from the element with atomic number Z=120

    International Nuclear Information System (INIS)

    Fregeau, M.O.; Morjean, M.; Bonnet, E.; Chbihi, A.; Frankland, J.D.; Jacquet, D.; Rivet, M.F.; Tassan-Got, L.; Dechery, F.; Drouart, A.; Nalpas, L.; Ledoux, X.; Parlog, M.; Parlog, M.; Ciortea, C.; Dumitriu, D.; Fluerasu, D.; Gugiu, M.; Gramegna, F.; Kravchuk, V.L.; Marchi, T.; Marchi, T.; Fabris, D.; Corsi, A.; Barlini, S.

    2012-01-01

    An atomic clock based on x-ray fluorescence yields has been used to estimate the mean characteristic time for fusion followed by fission in reactions 238 U + 64 Ni at 6.6 MeV/A. Inner shell vacancies are created during the collisions in the electronic structure of the possibly formed Z = 120 compound nuclei. The filling of these vacancies accompanied by a x-ray emission with energies characteristic of Z = 120 can take place only if the atomic transitions occur before nuclear fission. Therefore, the x-ray yield characteristic of the united atom with 120 protons is strongly related to the fission time and to the vacancy lifetimes. K x rays from the element with Z = 120 have been unambiguously identified from a coupled analysis of the involved nuclear reaction mechanisms and of the measured photon spectra. A minimum mean fission time τ f = 2.5 * 10 -18 s has been deduced for Z = 120 from the measured x-ray multiplicity. (authors)

  4. Applicability of multisyringe chromatography coupled to cold-vapor atomic fluorescence spectrometry for mercury speciation analysis

    International Nuclear Information System (INIS)

    Guzmán-Mar, J.L.; Hinojosa-Reyes, L.; Serra, A.M.; Hernández-Ramírez, A.; Cerdà, V.

    2011-01-01

    Graphical abstract: An automatic system, based on the applicability of multisyringe chromatography (MSC) coupled to cold-vapor atomic fluorescence spectrometry (CV/AFS) detection is developed for mercury speciation. Highlights: ► The on-line coupling of MSC to CV/AFS was developed for mercury speciation analysis. ► The speciation of MeHg + , Hg 2+ and EtHg + was achieved on a RP C18 monolithic column. ► The hyphenated system provided higher sample throughput compared to HPLC–CV/AFS. ► The limits of detection for mercury species were comparable or better than those reported by HPLC–CV/AFS. ► The developed method also provided low instrumental and operational costs. - Abstract: In this paper, a novel automatic approach for the speciation of inorganic mercury (Hg 2+ ), methylmercury (MeHg + ) and ethylmercury (EtHg + ) using multisyringe chromatography (MSC) coupled to cold-vapor atomic fluorescence spectrometry (CV/AFS) was developed. For the first time, the separation of mercury species was accomplished on a RP C18 monolithic column using a multi-isocratic elution program. The elution protocol involved the use of 0.005% 2-mercapthoethanol in 240 mM ammonium acetate (pH 6)–acetonitrile (99:1, v/v), followed by 0.005% 2-mercapthoethanol in 240 mM ammonium acetate (pH 6)–acetonitrile (90:10, v/v). The eluted mercury species were then oxidized under post-column UV radiation and reduced using tin(II) chloride in an acidic medium. Subsequently, the generated mercury metal were separated from the reaction mixture and further atomized in the flame atomizer and detected by AFS. Under the optimized experimental conditions, the limits of detection (3σ) were found to be 0.03, 0.11 and 0.09 μg L −1 for MeHg + , Hg 2+ and EtHg + , respectively. The relative standard deviation (RSD, n = 6) of the peak height for 3, 6 and 3 μg L −1 of MeHg + , Hg 2+ and EtHg + (as Hg) ranged from 2.4 to 4.0%. Compared with the conventional HPLC–CV/AFS hyphenated systems

  5. UV light-emitting-diode photochemical mercury vapor generation for atomic fluorescence spectrometry.

    Science.gov (United States)

    Hou, Xiaoling; Ai, Xi; Jiang, Xiaoming; Deng, Pengchi; Zheng, Chengbin; Lv, Yi

    2012-02-07

    A new, miniaturized and low power consumption photochemical vapor generation (PVG) technique utilizing an ultraviolet light-emitting diode (UV-LED) lamp is described, and further validated via the determination of trace mercury. In the presence of formic acid, the mercury cold vapor is favourably generated from Hg(2+) solutions by UV-LED irradiation, and then rapidly transported to an atomic fluorescence spectrometer for detection. Optimum conditions for PVG and interferences from concomitant elements were investigated in detail. Under optimum conditions, a limit of detection (LOD) of 0.01 μg L(-1) was obtained, and the precision was better than 3.2% (n = 11, RSD) at 1 μg L(-1) Hg(2+). No obvious interferences from any common ions were evident. The methodology was successfully applied to the determination of mercury in National Research Council Canada DORM-3 fish muscle tissue and several water samples.

  6. Determination of cadmium in seawater by chelate vapor generation atomic fluorescence spectrometry

    Science.gov (United States)

    Sun, Rui; Ma, Guopeng; Duan, Xuchuan; Sun, Jinsheng

    2018-03-01

    A method for the determination of cadmium in seawater by chelate vapor generation (Che-VG) atomic fluorescence spectrometry is described. Several commercially available chelating agents, including ammonium pyrrolidine dithiocarbamate (APDC), sodium dimethyl dithiocarbamate (DMDTC), ammonium dibutyl dithiophosphate (DBDTP) and sodium O,O-diethyl dithiophosphate (DEDTP), are compared with sodium diethyldithiocarbamate (DDTC) for the Che-VG of cadmium, and results showed that DDTC and DEDTP had very good cadmium signal intensity. The effect of the conditions of Che-VG with DDTC on the intensity of cadmium signal was investigated. Under the optimal conditions, 85 ± 3% Che-VG efficiency is obtained for cadmium. The detection limit (3σ) obtained in the optimal conditions was 0.19 ng ml- 1. The relative standard deviation (RSD, %) for ten replicate determinations at 2 ng ml- 1 Cd was 3.42%. The proposed method was successfully applied to the ultratrace determination of cadmium in seawater samples by the standard addition method.

  7. Resonance Fluorescence of a Trapped Four-Level Atom with Bichromatic Driving

    International Nuclear Information System (INIS)

    Bergou, J.; Jakob, M.; Abranyos, Y.

    1999-01-01

    The resonance fluorescence spectrum of a bichromatically driven four-level atom is polarization dependent. Very narrow lines occur in the incoherent parts of the spectrum for polarization directions which are different from that of the driving fields. The degree of squeezing has a maximum of 56% which should make it easily observable. The second-order correlation function exhibits anti bunching for zero time delay and strong super bunching for certain values of the interaction parameter and time delay. For these parameters resonant two-photon emission takes place in the form of polarization entangled photon pairs. The system can be a novel source of photons in the EPR and/or Bell states. Some experiments will be proposed which make use of this unique source. (Authors)

  8. Determination of Te in soldering tin using continuous flowing electrochemical hydride generation atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    Jiang Xianjuan; Gan Wuer; Han Suping; He Youzhao

    2008-01-01

    An electrochemical hydride generation system was developed for the detection of Te by coupling an electrochemical hydride generator with atomic fluorescence spectrometry. Since TeH 2 is unstable and easily decomposes in solution, a reticular W filament cathode was used in the present system. The TeH 2 generated on the cathode surface was effectively driven out by sweeping gas from the cathode chamber. In addition, a low temperature electrochemical cell (10 deg. C) was applied to reduce the decomposition of TeH 2 in solution. The limit of detection (LOD) was 2.2 ng ml -1 and the relative standard deviation (RSD) was 3.9% for nine consecutive measurements of standard solution. This method was successfully employed for determination of Te in soldering tin material

  9. Heavy atom induced room temperature fluorescence quenching of PAH from a glucose glass

    Energy Technology Data Exchange (ETDEWEB)

    Marlow, Matt, E-mail: matthew.marlow@nicholls.edu

    2017-06-15

    Sugar glasses are a relatively new matrix for solid-matrix luminescence. Molecular interactions within the sugar glass are not well understood. Fluorescence quenching was used to investigate molecular interactions within the sugar glass matrix. The room temperature fluorescence quenching of pyrene and naphthalene was observed from a glucose glass. The heavy atom salt NaI was the quencher. Two solvent compositions 50/50 and 60/40 MeOH/water, used for glass preparation, were examined for their effect on glass rigidity and molecular interactions. A complex static mechanism was observed for glasses prepared with 50/50 MeOH/water. This data was fit to the sphere of action model and associations constants determined. A Stern-Volmer static mechanism of quenching was observed for glasses prepared with 60/40 MeOH/water. This data fit the Stern-Volmer equation and association constants were determined. A larger association constant was observed for pyrene compared to naphthalene for both solvent systems used. Pyrene had a larger association constant with a sugar glass prepared with 60/40 MeOH/water compared to 50/50 MeOH/water implying a greater association between pyrene and iodide. The greater association is a reflection of a more rigid internal environment for the sugar glass prepared with 60/40 MeOH/water.

  10. The role of total-reflection x-ray fluorescence in atomic spectroscopy

    International Nuclear Information System (INIS)

    Toelg, G.; Klockenkaemper, R.

    1993-01-01

    Total-reflection X-ray fluorescence (TXRF) is a universal and economic method for the simultaneous determination of elements with atomic numbers > 11 down to the lower pg-level. It is a microanalytical tool for the analysis of small sample amounts placed on flat carriers and for contaminations on flat sample surfaces. Analyses of stratified near-surface layers are made possible by varying the incident angle of the primary beam in the region of total-reflection. This non-destructive method is especially suitable for thin layers of a few nanometres, deposited on wafer material although not usable as a microprobe method with a high lateral resolution. Furthermore, depth profiles of biological samples can be recorded by means of microtome sectioning of only a few micrometres, as, for example in the gradient analysis of human organs. In addition to micro- and surface-layer analysis, TXRF is effectively applied to element trace analysis. Homogeneous solutions, for example aqueous solutions, high-purity acids or body fluids, are pipetted onto carriers and, after evaporation, the dry residues are analyzed directly down to the pg/ml region. Particularly advantageous is the absence of matrix effects, so that an easy calibration can be carried out by adding a single internal standard element. A digestion or separation step preceding the actual determination becomes necessary if a more complex matrix is to be analysed or especially low detection limits have to be reached. A critical evaluation of the recent developments in atomic spectroscopy places TXRF in a leading position. Its outstanding features compete with those of e.g. electrothermal atomic absorption spectrometry (ETAAS), microwave induced plasma optical emission spectroscopy (MIP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) in the field of micro- and trace analysis and with Rutherford backscattering (RBS) and secondary ion mass spectrometry (SIMS) in the surface-layer analysis. (author)

  11. Sensitized fluorescence in thallium induced in collisions with Hg(6/sup 3/P/sub 1/) atoms

    Energy Technology Data Exchange (ETDEWEB)

    Wade, M K; Czajkowski, M; Krause, L [Windsor Univ., Ontario (Canada). Dept. of Physics

    1978-07-01

    The transfer of excitation from excited mercury atoms to ground-state thallium atoms was investigated using techniques of sensitized fluorescence. A Hg-Tl vapor mixture contained in a quartz cell was irradiated with Hg 2537 A resonance radiation which caused the mercury atoms to become excited to the 6/sup 3/P/sub 1/ state. Subsequent collisions between the Hg(6/sup 3/P/sub 1/) and Tl(6/sup 2/Psub(1/2)) atoms resulted in the population of the 8/sup 2/Ssub(1/2), 6/sup 2/D, and 7/sup 2/Ssub(1/2) thallium states, whose decay gave rise to sensitized fluorescence of wavelengths 3231, 3520, 3776, and 5352 A. Intensity measurements on the sensitized fluorescence and on the Hg 2537 A resonance fluorescence, observed at right angles to the direction of excitation, yielded cross sections of 3.0, 0.3, and 0.05 A/sup 2/ for collisional excitation transfer from Hg(6/sup 3/P/sub 1/) to the 8/sup 2/Ssub(1/2), 6/sup 2/D, and 7/sup 2/Ssub(1/2) states in thallium, respectively. The results are fully consistent with previously determined cross sections for excitation transfer in other binary metallic vapor systems.

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

    DEFF Research Database (Denmark)

    Norlén, Lars; Plasencia Gil, Maria Inés; Bagatolli, Luis

    2008-01-01

    -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...

  13. Application of laser fluorescence spectroscopy by two-photon excitation into atomic hydrogen density measurement in reactive plasmas

    International Nuclear Information System (INIS)

    Kajiwara, Toshinori; Takeda, Kazuyuki; Kim, Hee Je; Park, Won Zoo; Muraoka, Katsunori; Akazaki, Masanori; Okada, Tatsuo; Maeda, Mitsuo.

    1990-01-01

    Density profiles of hydrogen atoms in reactive plasmas of hydrogen and methane gases were measured, for the first time, using the laser fluorescence spectroscopy by two-photon excitation of Lyman beta transition and observation at the Balmer alpha radiation. Absolute density determinations showed atomic densities of around 3 x 10 17 m -3 , or the degree of dissociation to be 10 -4 . Densities along the axis perpendicular to the RF electrode showed peaked profiles, which were due to the balance of atomic hydrogen production by electron impact on molecules against diffusion loss to the walls. (author)

  14. Atomic imaging by x-ray-fluorescence holography and electron-emission holography: A comparative theoretical study

    International Nuclear Information System (INIS)

    Len, P.M.; Thevuthasan, S.; Fadley, C.S.; Kaduwela, A.P.; Van Hove, M.A.

    1994-01-01

    We consider from a theoretical viewpoint the direct imaging of atoms at and near the surfaces of solids by both x-ray-fluorescence holography (XFH) and electron-emission holography (EEH). The more ideal nature of x-ray scattering makes XFH images superior to those in single-energy EEH. The overlap of real and twin features for pairs of atoms at ±a can cause their XFH or EEH atomic images to cancel for certain combinations of wave vector and |a|. The relative merits of XFH and EEH for structure studies are considered

  15. In situ detection of atomic and molecular iodine using Resonance and Off-Resonance Fluorescence by Lamp Excitation: ROFLEX

    Directory of Open Access Journals (Sweden)

    J. C. Gómez Martín

    2011-01-01

    Full Text Available We demonstrate a new instrument for in situ detection of atmospheric iodine atoms and molecules based on atomic and molecular resonance and off-resonance ultraviolet fluorescence excited by lamp emission. The instrument combines the robustness, light weight, low power consumption and efficient excitation of radio-frequency discharge light sources with the high sensitivity of the photon counting technique. Calibration of I2 fluorescence is achieved via quantitative detection of the molecule by Incoherent Broad Band Cavity-enhanced Absorption Spectroscopy. Atomic iodine fluorescence signal is calibrated by controlled broad band photolysis of known I2 concentrations in the visible spectral range at atmospheric pressure. The instrument has been optimised in laboratory experiments to reach detection limits of 1.2 pptv for I atoms and 13 pptv for I2, for S/N = 1 and 10 min of integration time. The ROFLEX system has been deployed in a field campaign in northern Spain, representing the first concurrent observation of ambient mixing ratios of iodine atoms and molecules in the 1–350 pptv range.

  16. 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.

  17. 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. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Redox speciation analysis of antimony in soil extracts by hydride generation atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    Fuentes, Edwar; Pinochet, Hugo; Gregori, Ida de; Potin-Gautier, Martine

    2003-01-01

    A sensitive atomic spectrometric method for the redox speciation analysis of antimony in soils is described. The method is based on the selective generation of stibine from Sb(III) in a continuous flow system using atomic fluorescence spectrometry for detection. Sb(V) is masked by citric or oxalic acid in HCl medium. The procedure was optimized with synthetic solutions of Sb(III) and Sb(V). The effect of carboxylic acid and HCl concentration on the recovery of Sb(III) and Sb(V) species from standard solutions, and on the fluorescence signal were studied. Both species were extracted from soil with H 2 O, 0.05 mol l -1 EDTA and 0.25 mol l -1 H 2 SO 4 . Since the soil samples were collected from sites impacted by copper mining activities, the effect of Cu 2+ on the determination of antimony in synthetic solutions and soil extracts was studied. Cu 2+ decreased the Sb(III) signal, but had no effect on the total antimony determination. Therefore, the selective determination of Sb(III) was carried out in citric acid-HCl medium, using the analyte addition technique. Total antimony in soil extracts was determined using the standard calibration technique after reducing Sb(V) to Sb(III) at room temperature with KI-ascorbic acid. The Sb(V) concentration was calculated from the difference between total antimony and Sb(III). The limits of detection (PS Analytical, Excalibur Millennium model) were 17 and 10 ng l -1 for Sb(III) and total antimony, respectively, and the R.S.D. at the 0.5-μg l -1 level were 2.5 and 2.4%, respectively. The total antimony concentration of soils is in the mg kg -1 range; the Sb recovery from the different soils by the extracting solutions was between less than 0.02% and approximately 10%. Similar recoveries were obtained using EDTA and sulfuric acid solutions. Sb(V) was found to be the main antimony species extracted from soils

  19. Applicability of multisyringe chromatography coupled to cold-vapor atomic fluorescence spectrometry for mercury speciation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Guzman-Mar, J.L.; Hinojosa-Reyes, L. [Department of Chemistry Sciences, Universidad Autonoma de Nuevo Leon, Cd. Universitaria, Pedro de Alba s/n, C.P. 66451 San Nicolas de los Garza, Nuevo Leon (Mexico); Serra, A.M. [Department of Chemistry, University of the Balearic Islands, E-07122 Palma de Mallorca (Spain); Hernandez-Ramirez, A. [Department of Chemistry Sciences, Universidad Autonoma de Nuevo Leon, Cd. Universitaria, Pedro de Alba s/n, C.P. 66451 San Nicolas de los Garza, Nuevo Leon (Mexico); Cerda, V., E-mail: victor.cerda@uib.es [Department of Chemistry, University of the Balearic Islands, E-07122 Palma de Mallorca (Spain)

    2011-12-05

    Graphical abstract: An automatic system, based on the applicability of multisyringe chromatography (MSC) coupled to cold-vapor atomic fluorescence spectrometry (CV/AFS) detection is developed for mercury speciation. Highlights: Black-Right-Pointing-Pointer The on-line coupling of MSC to CV/AFS was developed for mercury speciation analysis. Black-Right-Pointing-Pointer The speciation of MeHg{sup +}, Hg{sup 2+} and EtHg{sup +} was achieved on a RP C18 monolithic column. Black-Right-Pointing-Pointer The hyphenated system provided higher sample throughput compared to HPLC-CV/AFS. Black-Right-Pointing-Pointer The limits of detection for mercury species were comparable or better than those reported by HPLC-CV/AFS. Black-Right-Pointing-Pointer The developed method also provided low instrumental and operational costs. - Abstract: In this paper, a novel automatic approach for the speciation of inorganic mercury (Hg{sup 2+}), methylmercury (MeHg{sup +}) and ethylmercury (EtHg{sup +}) using multisyringe chromatography (MSC) coupled to cold-vapor atomic fluorescence spectrometry (CV/AFS) was developed. For the first time, the separation of mercury species was accomplished on a RP C18 monolithic column using a multi-isocratic elution program. The elution protocol involved the use of 0.005% 2-mercapthoethanol in 240 mM ammonium acetate (pH 6)-acetonitrile (99:1, v/v), followed by 0.005% 2-mercapthoethanol in 240 mM ammonium acetate (pH 6)-acetonitrile (90:10, v/v). The eluted mercury species were then oxidized under post-column UV radiation and reduced using tin(II) chloride in an acidic medium. Subsequently, the generated mercury metal were separated from the reaction mixture and further atomized in the flame atomizer and detected by AFS. Under the optimized experimental conditions, the limits of detection (3{sigma}) were found to be 0.03, 0.11 and 0.09 {mu}g L{sup -1} for MeHg{sup +}, Hg{sup 2+} and EtHg{sup +}, respectively. The relative standard deviation (RSD, n = 6) of the

  20. Achieving 100% Efficient Postcolumn Hydride Generation for As Speciation Analysis by Atomic Fluorescence Spectrometry.

    Science.gov (United States)

    Marschner, Karel; Musil, Stanislav; Dědina, Jiří

    2016-04-05

    An experimental setup consisting of a flow injection hydride generator coupled to an atomic fluorescence spectrometer was optimized in order to generate arsanes from tri- and pentavalent inorganic arsenic species (iAs(III), iAs(V)), monomethylarsonic acid (MAs(V)), and dimethylarsinic acid (DMAs(V)) with 100% efficiency with the use of only HCl and NaBH4 as the reagents. The optimal concentration of HCl was 2 mol L(-1); the optimal concentration of NaBH4 was 2.5% (m/v), and the volume of the reaction coil was 8.9 mL. To prevent excessive signal noise due to fluctuations of hydride supply to an atomizer, a new design of a gas-liquid separator was implemented. The optimized experimental setup was subsequently interfaced to HPLC and employed for speciation analysis of arsenic. Two chromatography columns were tested: (i) ion-pair chromatography and (ii) ion exchange chromatography. The latter offered much better results for human urine samples without a need for sample dilution. Due to the equal hydride generation efficiency (and thus the sensitivities) of all As species, a single species standardization by DMAs(V) standard was feasible. The limits of detection for iAs(III), iAs(V), MAs(V), and DMAs(V) were 40, 97, 57, and 55 pg mL(-1), respectively. Accuracy of the method was tested by the analysis of the standard reference material (human urine NIST 2669), and the method was also verified by the comparative analyses of human urine samples collected from five individuals with an independent reference method.

  1. 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}.

  2. [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.

  3. Elasticity maps of living neurons measured by combined fluorescence and atomic force microscopy.

    Science.gov (United States)

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

    2012-09-05

    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 kPa (cortical). In contrast, dorsal root ganglion neurons are stiffer than P-19 and cortical cells, yielding elastic moduli in the range 0.1-8 kPa, with typical average values of 0.9 kPa. Finally, we report no measurable influence of substrate protein coating on cell body elasticity for the three types of neurons. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  4. Atomic layer deposition to prevent metal transfer from implants: An X-ray fluorescence study

    Energy Technology Data Exchange (ETDEWEB)

    Bilo, Fabjola [INSTM and Chemistry for Technologies Laboratory, University of Brescia, via Branze, 38, 25123 Brescia (Italy); Borgese, Laura, E-mail: laura.borgese@unibs.itl [INSTM and Chemistry for Technologies Laboratory, University of Brescia, via Branze, 38, 25123 Brescia (Italy); Prost, Josef; Rauwolf, Mirjam; Turyanskaya, Anna; Wobrauschek, Peter; Kregsamer, Peter; Streli, Christina [Atominstitut, TU Wien, Stadionallee 2, 1020 Vienna (Austria); Pazzaglia, Ugo [Dipartimento Specialità Medico Chirurgiche Sc. Radiol. e Sanità Pubblica, University of Brescia, v.le Europa, 11, 25121 Brescia (Italy); Depero, Laura E. [INSTM and Chemistry for Technologies Laboratory, University of Brescia, via Branze, 38, 25123 Brescia (Italy)

    2015-12-30

    Highlights: • Co and Cr migrate from bare alloy implant to the surrounding tissue showing a cluster distribution. • Co and Cr migrate from the TiO{sub 2} coated implant to the surrounding tissue showing a decreasing gradient distribution from the alloy surface. • TiO{sub 2} coating layers obtained by ALD on Co–Cr alloy show a barrier effect for the migration of metals. • The thicker the TiO{sub 2} layer deposited by ALD, the lower the metal migration. • The migration of metals from bare alloy toward the surrounding tissue increases with time. This effect is not detected in the coated samples. - Abstract: We show that Atomic Layer Deposition is a suitable coating technique to prevent metal diffusion from medical implants. The metal distribution in animal bone tissue with inserted bare and coated Co–Cr alloys was evaluated by means of micro X-ray fluorescence mapping. In the uncoated implant, the migration of Co and Cr particles from the bare alloy in the biological tissues is observed just after one month and the number of particles significantly increases after two months. In contrast, no metal diffusion was detected in the implant coated with TiO{sub 2}. Instead, a gradient distribution of the metals was found, from the alloy surface going into the tissue. No significant change was detected after two months of aging. As expected, the thicker is the TiO{sub 2} layer, the lower is the metal migration.

  5. Continuous flow hydride generation-atomic fluorescence spectrometric determination and speciation of arsenic in wine

    Energy Technology Data Exchange (ETDEWEB)

    Karadjova, Irina B. [Faculty of Chemistry, University of Sofia, 1 James Bourchier Blvd., Sofia 1164 (Bulgaria); Lampugnani, Leonardo [C.N.R. Istituto per i processi chimico-fisici, Area della Ricerca di Pisa, Via Moruzzi 1, 56124 Pisa (Italy)]. E-mail: lampugnani@ipcf.cnr.it; Onor, Massimo [C.N.R. Istituto per i processi chimico-fisici, Area della Ricerca di Pisa, Via Moruzzi 1, 56124 Pisa (Italy); D' Ulivo, Alessandro [C.N.R. Istituto per i processi chimico-fisici, Area della Ricerca di Pisa, Via Moruzzi 1, 56124 Pisa (Italy); Tsalev, Dimiter L. [Faculty of Chemistry, University of Sofia, 1 James Bourchier Blvd., Sofia 1164 (Bulgaria)

    2005-07-15

    Methods for the atomic fluorescence spectrometric (AFS) determination of total arsenic and arsenic species in wines based on continuous flow hydride generation (HG) with atomization in miniature diffusion flame (MDF) are described. For hydride-forming arsenic, L-cysteine is used as reagent for pre-reduction and complexation of arsenite, arsenate, monomethylarsonate and dimethylarsinate. Concentrations of hydrochloric acid and tetrahydroborate are optimized in order to minimize interference by ethanol. Procedure permits determination of the sum of these four species in 5-10-fold diluted samples with limit of detection (LOD) 0.3 and 0.6 {mu}g l{sup -1} As in white and red wines, respectively, with precision between 2% and 8% RSD at As levels within 0.5-10 {mu}g l{sup -1}. Selective arsine generation from different reaction media is used for non-chromatographic determination of arsenic species in wines: citrate buffer at pH 5.1 for As(III); 0.2 mol l{sup -1} acetic acid for arsenite + dimethylarsinate (DMA); 8 mol l{sup -1} HCl for total inorganic arsenic [As(III) + As(V)]; and monomethylarsonate (MMA) calculated by difference. Calibration with aqueous and ethanol-matched standard solutions of As(III) is used for 10- and 5-fold diluted samples, respectively. The LODs are 0.4 {mu}g l{sup -1} for As(III) and 0.3 {mu}g l{sup -1} for the other three As species and precision is within 4-8% RSDs. Arsenic species in wine were also determined by coupling of ion chromatographic separation on an anion exchange column and HG-flame AFS detection. Methods were validated by means of recovery studies and comparative analyses by HG-AFS and electrothermal atomic absorption spectrometry after microwave digestion. The LODs were 0.12, 0.27, 0.15 and 0.13 {mu}g l{sup -1} (as As) and RSDs were 2-6%, 5-9%, 3-7% and 2-5% for As(III), As(V), MMA and DMA arsenic species, respectively. Bottled red and white wines from Bulgaria, Republic of Macedonia and Italy were analyzed by non

  6. Continuous flow hydride generation-atomic fluorescence spectrometric determination and speciation of arsenic in wine

    International Nuclear Information System (INIS)

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

    2005-01-01

    Methods for the atomic fluorescence spectrometric (AFS) determination of total arsenic and arsenic species in wines based on continuous flow hydride generation (HG) with atomization in miniature diffusion flame (MDF) are described. For hydride-forming arsenic, L-cysteine is used as reagent for pre-reduction and complexation of arsenite, arsenate, monomethylarsonate and dimethylarsinate. Concentrations of hydrochloric acid and tetrahydroborate are optimized in order to minimize interference by ethanol. Procedure permits determination of the sum of these four species in 5-10-fold diluted samples with limit of detection (LOD) 0.3 and 0.6 μg l -1 As in white and red wines, respectively, with precision between 2% and 8% RSD at As levels within 0.5-10 μg l -1 . Selective arsine generation from different reaction media is used for non-chromatographic determination of arsenic species in wines: citrate buffer at pH 5.1 for As(III); 0.2 mol l -1 acetic acid for arsenite + dimethylarsinate (DMA); 8 mol l -1 HCl for total inorganic arsenic [As(III) + As(V)]; and monomethylarsonate (MMA) calculated by difference. Calibration with aqueous and ethanol-matched standard solutions of As(III) is used for 10- and 5-fold diluted samples, respectively. The LODs are 0.4 μg l -1 for As(III) and 0.3 μg l -1 for the other three As species and precision is within 4-8% RSDs. Arsenic species in wine were also determined by coupling of ion chromatographic separation on an anion exchange column and HG-flame AFS detection. Methods were validated by means of recovery studies and comparative analyses by HG-AFS and electrothermal atomic absorption spectrometry after microwave digestion. The LODs were 0.12, 0.27, 0.15 and 0.13 μg l -1 (as As) and RSDs were 2-6%, 5-9%, 3-7% and 2-5% for As(III), As(V), MMA and DMA arsenic species, respectively. Bottled red and white wines from Bulgaria, Republic of Macedonia and Italy were analyzed by non-chromatographic and chromatographic procedures and the As

  7. Evaluation of the wavelet image two-line coder

    DEFF Research Database (Denmark)

    Rein, Stephan Alexander; Fitzek, Frank Hanns Paul; Gühmann, Clemens

    2015-01-01

    This paper introduces the wavelet image two-line (Wi2l) coding algorithm for low complexity compression of images. The algorithm recursively encodes an image backwards reading only two lines of a wavelet subband, which are read in blocks of 512 bytes from flash memory. It thus only requires very ...

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

    Science.gov (United States)

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

    2011-01-01

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

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

    International Nuclear Information System (INIS)

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

    2003-01-01

    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 2 PO 4 /K 2 HPO 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 μl, a 4.0% (m/v) solution of sodium tetrahydroborate and 2.0 mol l -1 hydrochloric acid with flow rates of 2.7 and 1.7 ml min -1 , respectively and a flow rate of 500 ml min -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 μg l -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 μg l -1 . Recovery and comparative studies evidenced that the method is suitable for the accurate determination of arsenic species in water and beer samples

  10. 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.

  11. Femtosecond, two-photon laser-induced-fluorescence imaging of atomic oxygen in an atmospheric-pressure plasma jet

    Science.gov (United States)

    Schmidt, Jacob B.; Sands, Brian L.; Kulatilaka, Waruna D.; Roy, Sukesh; Scofield, James; Gord, James R.

    2015-06-01

    Femtosecond, two-photon-absorption laser-induced-fluorescence (fs-TALIF) spectroscopy is employed to measure space- and time-resolved atomic-oxygen distributions in a nanosecond, repetitively pulsed, externally grounded, atmospheric-pressure plasma jet flowing helium with a variable oxygen admixture. The high-peak-intensity, low-average-energy femtosecond pulses result in increased TALIF signal with reduced photolytic inferences. This allows 2D imaging of absolute atomic-oxygen number densities ranging from 5.8   ×   1015 to 2.0   ×   1012cm-3 using a cooled CCD with an external intensifier. Xenon is used for signal and imaging-system calibrations to quantify the atomic-oxygen fluorescence signal. Initial results highlight a transition in discharge morphology from annular to filamentary, corresponding with a change in plasma chemistry from ozone to atomic oxygen production, as the concentration of oxygen in the feed gas is changed at a fixed voltage-pulse-repetition rate. In this configuration, significant concentrations of reactive oxygen species may be remotely generated by sustaining an active discharge beyond the confines of the dielectric capillary, which may benefit applications that require large concentrations of reactive oxygen species such as material processing or biomedical devices.

  12. Distribution of Fe atom density in a dc magnetron sputtering plasma source measured by laser-induced fluorescence imaging spectroscopy

    Science.gov (United States)

    Shibagaki, K.; Nafarizal, N.; Sasaki, K.; Toyoda, H.; Iwata, S.; Kato, T.; Tsunashima, S.; Sugai, H.

    2003-10-01

    Magnetron sputtering discharge is widely used as an efficient method for thin film fabrication. In order to achieve the optimized fabrication, understanding of the kinetics in plasmas is essential. In the present work, we measured the density distribution of sputtered Fe atoms using laser-induced fluorescence imaging spectroscopy. A dc magnetron plasma source with a Fe target was used. An area of 20 × 2 mm in front of the target was irradiated by a tunable laser beam having a planar shape. The picture of laser-induced fluorescence on the laser beam was taken using an ICCD camera. In this way, we obtained the two-dimensional image of the Fe atom density. As a result, it has been found that the Fe atom density observed at a distance of several centimeters from the target is higher than that adjacent to the target, when the Ar gas pressure was relatively high. It is suggested from this result that some gas-phase production processes of Fe atoms are available in the plasma. This work has been performed under the 21st Century COE Program by the Ministry of Education, Culture, Sports, Science and Technology in Japan.

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

    Science.gov (United States)

    Ono, Ryo; Takezawa, Kei; Oda, Tetsuji

    2009-08-01

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

  14. 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

  15. 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,…

  16. A new Technique for ultrafast velocity distribution measurements of atomic species by post-ionization laser induced fluorescence (PILIF)

    International Nuclear Information System (INIS)

    Tabares, F.L.

    1992-01-01

    A new method for single shot velocity distribution measurement of metallic impurities of relevance for studies involving continuous sources, such as limiter experiments in fusion devices or sputtering experiments, based in the combination of Resonant Enhanced Multiphoton Ionization (REMPI) and Laser Induced Fluorescence (LIF) is proposed. High ionization yield and good time resolution are expected according to the numerical simulation of the experiment that has been run for several atomic species. Other possible applications of REMPI to plasma edge physics and to conventional techniques for velocity distribution measurements are briefly addressed. (author)

  17. A new technique for ultrafast velocity distribution measurements of atomic species by post-ionization laser induced fluorescent (PILIF)

    International Nuclear Information System (INIS)

    Tabares, F.L.

    1992-01-01

    A new method for single shot velocity distribution measurement of metallic impurities of relevance for studies involving continuous sources, such as limiter experiments in fusion devices or sputtering experiments, based in the combination of Resonant Enhanced Multiphoton ionization (REMPI) and Laser Induced Fluorescence (LIF) is proposed. High ionization yield and good time resolution are expected according to the numerical simulation of the experiment that has been run for several atomic species. Other possible applications of REMPI to plasma edge physics and to conventional techniques for velocity distribution measurements are briefly addressed. (Author) 8 refs

  18. A new technique for ultrafast velocity distribution measurements of atomic species by post-ionization laser induced fluorescent (PILIF)

    Energy Technology Data Exchange (ETDEWEB)

    Tabares, F.L.

    1992-07-01

    A new method for single shot velocity distribution measurement of metallic impurities of relevance for studies involving continuous sources, such as limiter experiments in fusion devices or sputtering experiments, based in the combination of Resonant Enhanced Multiphoton ionization (REMPI) and Laser Induced Fluorescence (LIF) is proposed. High ionization yield and good time resolution are expected according to the numerical simulation of the experiment that has been run for several atomic species. Other possible applications of REMPI to plasma edge physics and to conventional techniques for velocity distribution measurements are briefly addressed. (Author) 8 refs.

  19. Atoms

    International Nuclear Information System (INIS)

    Fuchs, Alain; Villani, Cedric; Guthleben, Denis; Leduc, Michele; Brenner, Anastasios; Pouthas, Joel; Perrin, Jean

    2014-01-01

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

  20. 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.

  1. The physics of fluorescent lamps: Do we understand the atomic processes?

    International Nuclear Information System (INIS)

    Lister, Graeme G.

    2002-01-01

    Numerical models have provided insight into the operation of 'standard' fluorescent lamps for more than 40 years. Recent developments in the lighting industry have led to products with much higher power loadings, for which modeling has been less successful in reproducing the experimental results. One of the potential weaknesses of the models is the absence of fundamental data to describe important phenomena in these 'highly loaded lamps'. The current state of our knowledge of available data is reviewed, together with an overview of the recently completed ALITE 1 project to reexamine the fundamental properties of fluorescent lamp operation

  2. 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.

  3. 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.

  4. Analysis of Indium Tin Oxide Film Using Argon Fluroide (ArF) Laser-Excited Atomic Fluorescence of Ablated Plumes.

    Science.gov (United States)

    Ho, Sut Kam; Garcia, Dario Machado

    2017-04-01

    A two-pulse laser-excited atomic fluorescence (LEAF) technique at 193 nm wavelength was applied to the analysis of indium tin oxide (ITO) layer on polyethylene terephthalate (PET) film. Fluorescence emissions from analytes were induced from plumes generated by first laser pulse. Using this approach, non-selective LEAF can be accomplished for simultaneous multi-element analysis and it overcomes the handicap of strict requirement for laser excitation wavelength. In this study, experimental conditions including laser fluences, times for gating and time delay between pulses were optimized to reveal high sensitivity with minimal sample destruction and penetration. With weak laser fluences of 100 and 125 mJ/cm 2 for 355 and 193 nm pulses, detection limits were estimated to be 0.10% and 0.43% for Sn and In, respectively. In addition, the relation between fluorescence emissions and number of laser shots was investigated; reproducible results were obtained for Sn and In. It shows the feasibility of depth profiling by this technique. Morphologies of samples were characterized at various laser fluences and number of shots to examine the accurate penetration. Images of craters were also investigated using scanning electron microscopy (SEM). The results demonstrate the imperceptible destructiveness of film after laser shot. With such weak laser fluences and minimal destructiveness, this LEAF technique is suitable for thin-film analysis.

  5. Metal-atom fluorescence from the quenching of metastable rare gases by metal carbonyls

    International Nuclear Information System (INIS)

    Hollingsworth, W.E.

    1982-11-01

    A flowing afterglow apparatus was used to study the metal fluorescence resulting from the quenching of metastable rare-gas states by metal carbonyls. The data from the quenching or argon, neon, and helium by iron and nickel carbonyl agreed well with a restricted degree of freedom model indicating a concerted bond-breaking dissociation

  6. Application of Atomic Fluorescence to Measurement of Combustion Temperature in Solid Propellants.

    Science.gov (United States)

    1986-12-04

    into a cytal (yttrium- aluminum -garnet) is shown to be an ideal seed, the fluoresce. f which is stimulated by the ultra-violet output of a Nd:YAG...been successfully employed in atmospheric flames for making thermometric measurements. However, because of the amorphous nature of energetic materials...be determined. R. 6 A .6 An example of this type of behavior is found in trivalent dysprosium, doped at 3% in yttrium- aluminum -garnet (Dy+3 :YAG

  7. Atom

    International Nuclear Information System (INIS)

    Auffray, J.P.

    1997-01-01

    The atom through centuries, has been imagined, described, explored, then accelerated, combined...But what happens truly inside the atom? And what are mechanisms who allow its stability? Physicist and historian of sciences, Jean-Paul Auffray explains that these questions are to the heart of the modern physics and it brings them a new lighting. (N.C.)

  8. Local mobility in lipid domains of supported bilayers characterized by atomic force microscopy and fluorescence correlation spectroscopy.

    Energy Technology Data Exchange (ETDEWEB)

    Frankel, Daniel J.; Buranda, T. (University of New Mexico, Albuquerque, NM); Burns, Alan Richard

    2005-01-01

    Fluorescence correlation spectroscopy (FCS) is used to examine mobility of labeled probes at specific sites in supported bilayers consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid domains in 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). Those sites are mapped beforehand with simultaneous atomic force microscopy and submicron confocal fluorescence imaging, allowing characterization of probe partitioning between gel DPPC and disordered liquid DOPC domains with corresponding topography of domain structure. We thus examine the relative partitioning and mobility in gel and disordered liquid phases for headgroup- and tailgroup-labeled GM1 ganglioside probes and for headgroup- and tailgroup-labeled phospholipid probes. For the GM1 probes, large differences in mobility between fluid and gel domains are observed; whereas unexpected mobility is observed in submicron gel domains for the phospholipid probes. We attribute the latter to domain heterogeneities that could be induced by the probe. Furthermore, fits to the FCS data for the phospholipid probes in the DOPC fluid phase require two components (fast and slow). Although proximity to the glass substrate may be a factor, local distortion of the probe by the fluorophore could also be important. Overall, we observe nonideal aspects of phospholipid probe mobility and partitioning that may not be restricted to supported bilayers.

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

    International Nuclear Information System (INIS)

    Teramoto, Yoshiyuki; Ono, Ryo; Oda, Tetsuji

    2012-01-01

    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 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 2 discharge pulse is estimated to be 2.9 - 9.8 × 10 13 atoms and the energy efficiency of atomic nitrogen production is estimated to be about 1.8 - 6.1 × 10 16 atoms/J. The energy efficiency of atomic nitrogen production in N 2 discharge is constant against the discharge energy, while that in N 2 /O 2 discharge increases with discharge energy. In the N 2 /O 2 discharge, two-step process of N 2 dissociation plays significant role for atomic nitrogen production.

  10. 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.

  11. Ultra-trace determination of methylmercuy in seafood by atomic fluorescence spectrometry coupled with electrochemical cold vapor generation

    Energy Technology Data Exchange (ETDEWEB)

    Zu, Wenchuan, E-mail: zuhongshuai@126.com [Beijing Institute of Technology, College of Chemistry, Beijing 100081 (China); Beijing Center for Physical & Chemical Analysis, Beijing 100089 (China); Wang, Zhenghao [Beijing Normal University, College of Chemistry, Beijing 100875 (China)

    2016-03-05

    Highlights: • Methylmercury detection by ECVG-AFS without pre-separation by HPLC is proposed. • Methylmercury is atomized by direct electrochemical reduction with no reductant. • Remarkably better sensitivity is obtained than the traditional HPLC-UV-AFS method. • Glassy carbon is the best cathode material to generate Hg vapor from methylmercury. - Abstract: A homemade electrochemical flow cell was adopted for the determination of methylmercury. The cold vapor of mercury atoms was generated from the surface of glassycarbon cathode through the method of electrolytic reduction and detected by atomic fluorescence spectroscopy subsequently. The operating conditions were optimized with 2 ng mL{sup −1} methylmercury standard solution. The caliberation curve was favorably linear when the concentrations of standard HgCH{sub 3}{sup +} solutions were in the range of 0.2–5 ng mL{sup −1}(as Hg). Under the optimized conditions, the limit of detection (LOD) for methylmercury was 1.88 × 10{sup −3} ng mL{sup −1} and the precision evaluated by relative standard deviation was 2.0% for six times 2 ng mL{sup −1} standard solution replicates. The terminal analytical results of seafood samples, available from local market, showed that the methylmercury content ranged within 3.7–45.8 ng g{sup −1}. The recoveries for methylmercury spiked samples were found to be in the range of 87.6–103.6% and the relative standard deviations below 5% (n = 6)were acquired, which showed this method was feasible for real sample analysis.

  12. 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...

  13. Evaluation of an inductively-coupled plasma with an extended-sleeve torch as an atomization cell for laser-excited fluorescence spectrometry.

    Science.gov (United States)

    Kosinski, M A; Uchida, H; Winefordner, J D

    1983-05-01

    An inductively-coupled plasma (ICP) with an extended-sleeve torch has been evaluated as an atomization cell for laser-excited fluorescence spectrometry. Limits of detection for 20 lines are given. The detection power is almost equivalent to that obtained by excitation with a hollow-cathode lamp. Interelement effects and spectral interferences are discussed.

  14. 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.

    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

  15. 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.

  16. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Automated system for on-line determination of dimethylarsinic and inorganic arsenic by hydride generation-atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Chaparro, L.L.; Leal, L.O. [Renewable Energy and Environmental Protection Department, Advanced Materials Research Center (CIMAV), Chihuahua, Chihuahua (Mexico); Ferrer, L.; Cerda, V. [University of the Balearic Islands, Department of Chemistry, Palma de Mallorca (Spain)

    2012-09-15

    A multisyringe flow-injection approach has been coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS) with UV photo-oxidation for dimethylarsinic (DMA), inorganic As and total As determination, depending on the pre-treatment given to the sample (extraction or digestion). The implementation of a UV lamp allows on-line photo-oxidation of DMA and the following arsenic detection, whereas a bypass leads the flow directly to the HG-AFS system, performing inorganic arsenic determination. DMA concentration is calculated by the difference of total inorganic arsenic and measurement of the photo-oxidation step. The detection limits for DMA and inorganic arsenic were 0.09 and 0.47 {mu}g L{sup -1}, respectively. The repeatability values accomplished were of 2.4 and 1.8 %, whereas the injection frequencies were 24 and 28 injections per hour for DMA and inorganic arsenic, respectively. This method was validated by means of a solid reference material BCR-627 (muscle of tuna) with good agreement with the certified values. Satisfactory results for DMA and inorganic arsenic determination were obtained in several water matrices. The proposed method offers several advantages, such as increasing the sampling frequency, low detection limits and decreasing reagents and sample consumption, which leads to lower waste generation. (orig.)

  18. Determination of arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid in cereals by hydride generation atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Matos Reyes, M.N. [Department of Analytical Chemistry, University of Valencia, 50 Dr. Moliner Street, 46100 Burjassot, Valencia (Spain); Department of Chemistry, Pontificia Universidade Catolica do Rio de Janeiro, Rua Marques de Sao Vicente, 225, 22453-900, Rio de Janeiro, RJ (Brazil); Cervera, M.L. [Department of Analytical Chemistry, University of Valencia, 50 Dr. Moliner Street, 46100 Burjassot, Valencia (Spain)], E-mail: m.luisa.cervera@uv.es; Campos, R.C. [Department of Chemistry, Pontificia Universidade Catolica do Rio de Janeiro, Rua Marques de Sao Vicente, 225, 22453-900, Rio de Janeiro, RJ (Brazil); Guardia, M. de la [Department of Analytical Chemistry, University of Valencia, 50 Dr. Moliner Street, 46100 Burjassot, Valencia (Spain)

    2007-09-15

    A fast, sensitive and simple non-chromatographic analytical method was developed for the speciation analysis of toxic arsenic species in cereal samples, namely rice and wheat semolina. An ultrasound-assisted extraction of the toxic arsenic species was performed with 1 mol L{sup -1} H{sub 3}PO{sub 4} and 0.1% (m/v) Triton XT-114. After extraction, As(III), As(V), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) concentrations were determined by hydride generation atomic fluorescence spectrometry using a series of proportional equations corresponding to four different experimental reduction conditions. The detection limits of the method were 1.3, 0.9, 1.5 and 0.6 ng g{sup -1} for As(III), As(V), DMA and MMA, respectively, expressed in terms of sample dry weight. Recoveries were always greater than 90%, and no species interconversion occurred. The speciation analysis of a rice flour reference material certified for total arsenic led to coherent results, which were also in agreement with other speciation studies made on the same certified reference material.

  19. Determination of total and inorganic mercury in fish samples with on-line oxidation coupled to atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    Shao Lijun; Gan Wuer; Su Qingde

    2006-01-01

    An atomic fluorescence spectrometry system for determination of total and inorganic mercury with electromagnetic induction-assisted heating on-line oxidation has been developed. Potassium peroxodisulphate was used as the oxidizing agent to decompose organomercury compounds. Depending on the temperature selected, inorganic or total mercury could be determined with the same manifold. Special accent was put on the study of the parameters influencing the on-line digestion efficiency. The tolerance to the interference of coexisting ions was carefully examined in this system. Under optimal conditions, the detection limits (3σ) were evaluated to be 2.9 ng l -1 for inorganic mercury and 2.6 ng l -1 for total mercury, respectively. The relative standard deviations for 10 replicate determinations of 1.0 μg l -1 Hg were 2.4 and 3.2% for inorganic mercury and total mercury, respectively. The proposed method was successfully applied to the determination of total and inorganic mercury in fish samples

  20. Ultrasensitive determination of mercury in human saliva by atomic fluorescence spectrometry based on solidified floating organic drop microextraction

    International Nuclear Information System (INIS)

    Yuan, C.-G.; Wang, J.; Jin, Y.

    2012-01-01

    We report on a new, rapid and simple method for the determination of ultra-trace quantities of mercury ion in human saliva. It is based on solidified floating organic drop microextraction and detection by cold vapor atomic fluorescence spectrometry (CV-AFS). Mercury ion was complexed with diethyldithiocarbamate, and the hydrophobic complex was then extracted into fine droplets of 1-undecanol. By cooling in an ice bath after extraction, the droplets in solution solidify to form a single ball floating on the surface of solution. The solidified micro drop containing the mercury complex was then transferred for determination by CV-AFS. The effects of pH value, concentration of chelating reagent, quantity of 1-undecanol, sample volume, equilibration temperature and time were investigated. Under the optimum conditions, the preconcentration of a 25-mL sample is accomplished with an enrichment factor of 182. The limit of detection is 2.5 ng L -1 . The relative standard deviation for seven replicate determinations at 0.1 ng mL -1 level is 4.1%. The method was applied to the determination of mercury in saliva samples collected from four volunteers. Two volunteers having dental amalgam fillings had 0.4 ng mL -1 mercury in their saliva, whereas mercury was not detectable in the saliva of two volunteers who had no dental fillings. (author)

  1. Determination of mercury in ash and soil samples by oxygen flask combustion method-Cold vapor atomic fluorescence spectrometry (CVAFS)

    International Nuclear Information System (INIS)

    Geng Wenhua; Nakajima, Tsunenori; Takanashi, Hirokazu; Ohki, Akira

    2008-01-01

    A simple method was developed for the determination of mercury (Hg) in coal fly ash (CFA), waste incineration ash (WIA), and soil by use of oxygen flask combustion (OFC) followed by cold vapor atomic fluorescence spectrometry (CVAFS). A KMnO 4 solution was used as an absorbent in the OFC method, and the sample containing a combustion agent and an ash or soil sample was combusted by the OFC method. By use of Hg-free graphite as the combustion agent, the determination of Hg in ash and soil was successfully carried out; the Hg-free graphite was prepared by use of a mild pyrolysis procedure at 500 deg. C. For six certified reference materials (three CFA samples and three soil samples), the values of Hg obtained by this method were in good agreement with the certified or reference values. In addition, real samples including nine CFAs collected from some coal-fired power plants, five WIAs collected from waste incineration plants, and two soils were analyzed by the present method, and the data were compared to those from microwave-acid digestion (MW-AD) method

  2. Determination of methyl mercury by aqueous phase Eehylation, followed by gas chromatographic separation with cold vapor atomic fluorescence detection

    Science.gov (United States)

    De Wild, John F.; Olsen, Mark L.; Olund, Shane D.

    2002-01-01

    A recent national sampling of streams in the United States revealed low methyl mercury concentrations in surface waters. The resulting median and mean concentrations, calculated from 104 samples, were 0.06 nanograms per liter (ng/L) and 0.15 ng/L, respectively. This level of methyl mercury in surface water in the United States has created a need for analytical techniques capable of detecting sub-nanogram per liter concentrations. In an attempt to create a U.S. Geological Survey approved method, the Wisconsin District Mercury Laboratory has adapted a distillation/ethylation/ gas-phase separation method with cold vapor atomic fluorescence spectroscopy detection for the determination of methyl mercury in filtered and unfiltered waters. This method is described in this report. Based on multiple analyses of surface water and ground-water samples, a method detection limit of 0.04 ng/L was established. Precision and accuracy were evaluated for the method using both spiked and unspiked ground-water and surface-water samples. The percent relative standard deviations ranged from 10.2 to 15.6 for all analyses at all concentrations. Average recoveries obtained for the spiked matrices ranged from 88.8 to 117 percent. The precision and accuracy ranges are within the acceptable method-performance limits. Considering the demonstrated detection limit, precision, and accuracy, the method is an effective means to quantify methyl mercury in waters at or below environmentally relevant concentrations

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

    International Nuclear Information System (INIS)

    Potin-Gautier, M.; Pannier, F.; Quiroz, W.; Pinochet, H.; Gregori, I. de

    2005-01-01

    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 -1 for Sb(III) and TMSbCl2 and 40 ng g -1 for Sb(V) in sediment samples

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

    International Nuclear Information System (INIS)

    Zhou, Qingxiang; Zhao, Na; Xie, Guohong

    2011-01-01

    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 -1 (r 2 = 0.9990). The precision was 2.12% (RSD, n = 7) and the detection limit was 0.95 ng L -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%.

  5. Quenching of the OH and nitrogen molecular emission by methane addition in an Ar capacitively coupled plasma to remove spectral interference in lead determination by atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Frentiu, T., E-mail: ftibi@chem.ubbcluj.r [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca (Romania); Ponta, M., E-mail: mponta@chem.ubbcluj.r [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca (Romania); Mihaltan, A.I., E-mail: alinblaj2005@yahoo.co [National Institute for Research and Development of Optoelectronics Bucharest - Research Institute for Analytical Instrumentation, Donath 67, 400293 Cluj-Napoca (Romania); Darvasi, E., E-mail: edarvasi@chem.ubbcluj.r [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca (Romania); Frentiu, M., E-mail: frentiu.maria@yahoo.co [National Institute for Research and Development of Optoelectronics Bucharest - Research Institute for Analytical Instrumentation, Donath 67, 400293 Cluj-Napoca (Romania); Cordos, E., E-mail: emilcordos@gmail.co [National Institute for Research and Development of Optoelectronics Bucharest - Research Institute for Analytical Instrumentation, Donath 67, 400293 Cluj-Napoca (Romania)

    2010-07-15

    A new method is proposed to remove the spectral interference on elements in atomic fluorescence spectrometry by quenching of the molecular emission of the OH radical (A{sup 2{Sigma}+} {yields} X{sup 2{Pi}}) and N{sub 2} second positive system (C{sup 3{Pi}}{sub u} {yields} B{sup 3{Sigma}}{sub g}) in the background spectrum of medium power Ar plasmas. The experiments were carried out in a radiofrequency capacitively coupled plasma (275 W, 27.12 MHz) by CH{sub 4} addition. The quenching is the result of the high affinity of OH radical for a hydrogen atom from the CH{sub 4} molecule and the collisions of the second kind between nitrogen excited molecules and CH{sub 4}, respectively. The decrease of the emission of N{sub 2} second positive system in the presence of CH{sub 4} is also the result of the deactivation of the metastable argon atoms that could excite the nitrogen molecules. For flow rates of 0.7 l min{sup -1} Ar with addition of 7.5 ml min{sup -1} CH{sub 4}, the molecular emission of OH and N{sub 2} was completely removed from the plasma jet spectrum at viewing heights above 60 mm. The molecular emission associated to CH and CH{sub 2} species was not observed in the emission spectrum of Ar/CH{sub 4} plasma in the ultraviolet range. The method was experimented for the determination of Pb at 283.31 nm by atomic fluorescence spectrometry with electrodeless discharge lamp and a multichannel microspectrometer. The detection limit was 35 ng ml{sup -1}, 2-3 times better than in atomic emission spectrometry using the same plasma source, and similar to that in hollow cathode lamp microwave plasma torch atomic fluorescence spectrometry.

  6. [Improvement of the method for methylmercury determination in aquatic products using liquid chromatography online coupled with atomic fluorescence spectrometry].

    Science.gov (United States)

    Shang, Xiaohong; Zhao, Yunfeng; Zhang, Lei; Li, Xiaowei; Wu, Yongning

    2011-07-01

    The improvement method was developed for methylmercury determination using liquid chromatography online coupled with cold vapor atomic fluorescence spectrometry (LC-CV-AFS). 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 methylmercury was 1-50 microg/L and the limit of detection (S/N = 3) for methylmercury was 0.3 microg/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 microg/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 methylmercury determination in seafood.

  7. 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.

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

    Science.gov (United States)

    2014-04-01

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

  9. Removal of Chromophore-proximal Polar Atoms Decreases Water Content and Increases Fluorescence in a Near Infrared Phytofluor

    Directory of Open Access Journals (Sweden)

    Heli eLehtivuori

    2015-11-01

    Full Text Available Genetically encoded fluorescent markers have revolutionized cell and molecular biology due to their biological compatibility, controllable spatiotemporal expression, and photostability. To achieve in vivo imaging in whole animals, longer excitation wavelength probes are needed due to the superior ability of near infrared light to penetrate tissues unimpeded by absorbance from biomolecules or autofluorescence of water. Derived from near infrared-absorbing bacteriophytochromes, phytofluors are engineered to fluoresce in this region of the electromagnetic spectrum, although high quantum yield remains an elusive goal. An invariant aspartate residue is of utmost importance for photoconversion in native phytochromes, presumably due to the proximity of its backbone carbonyl to the pyrrole ring nitrogens of the biliverdin (BV chromophore as well as the size and charge of the side chain. We hypothesized that the polar interaction network formed by the charged side chain may contribute to the decay of the excited state via proton transfer. Thus, we chose to further probe the role of this amino acid by removing all possibility for polar interactions with its carboxylate side chain by incorporating leucine instead. The resultant fluorescent protein, WiPhy2, maintains BV binding, monomeric status, and long maximum excitation wavelength while minimizing undesirable protoporphyrin IXα binding in cells. A crystal structure and time-resolved fluorescence spectroscopy reveal that water near the BV chromophore is excluded and thus validate our hypothesis that removal of polar interactions leads to enhanced fluorescence by increasing the lifetime of the excited state. This new phytofluor maintains its fluorescent properties over a broad pH range and does not suffer from photobleaching. WiPhy2 achieves the best compromise to date between high fluorescence quantum yield and long illumination wavelength in this class of fluorescent proteins.

  10. Laser fluorescence spectroscopy by two-photon excitation for detection of hydrogen atoms in a periphery region of high temperature plasmas

    International Nuclear Information System (INIS)

    Kim, Hee-Je; Kajiwara, Toshinori; Motoyama, Sumio; Muraoka, Katsunori; Akazaki, Masanori; Okada, Tatsuo; Maeda, Mitsuo

    1989-01-01

    For measurements of atomic hydrogen density in the periphery region of high temperature plasmas, laser fluorescence spectroscopy (LFS) by two-photon excitation (1s-3s, 3d) was developed. Based upon the theoretical estimates for laser source requirements, which indicated the laser energy and spectral width to be more than 10 mJ (assuming the pulse duration of 10 ns) and several tens of picometers around the wavelength of 205.1 nm, respectively, the first Stokes generation in deuterium gas of ArF laser output was adopted and shown to have the necessary performance. Through the LFS experiment employing the laser source, the minimum detectable limit of atomic hydrogen, normalized by a laser power and an observing solid angle, was demonstrated to be 1 x 10 14 [m -3 · MW · sr], which is usually sufficient for the above purpose, and the accuracy of the density determination was shown to be within a factor 2. (author)

  11. Recent advances in on-line coupling of capillary electrophoresis to atomic absorption and fluorescence spectrometry for speciation analysis and studies of metal-biomolecule interactions

    International Nuclear Information System (INIS)

    Li Yan; Yin Xuebo; Yan Xiuping

    2008-01-01

    Speciation information is vital for the understanding of the toxicity, mobility and bioavailability of elements in environmental or biological samples. Hyphenating high resolving power of separation techniques and element-selective detectors provides powerful tools for studying speciation of trace elements in environmental and biological systems. During the last five years several novel hybrid techniques based on capillary electrophoresis (CE) and atomic spectrometry have been developed for speciation analysis and metal-biomolecule interaction study in our laboratory. These techniques include CE on-line coupled with atomic fluorescence spectrometry (AFS), chip-CE on-line coupled with AFS, CE on-line coupled with flame heated quartz furnace atomic absorption spectrometry (FHF-AAS), and CE on-line coupled with electrothermal atomic absorption spectrometry (ETAAS). The necessity for the development of these techniques, their interface design, and applications in speciation analysis and metal-biomolecule interaction study are reviewed. The advantages and limitations of the developed hybrid techniques are critically discussed, and further development is also prospected

  12. Covariance Estimation and Autocorrelation of NORAD Two-Line Element Sets

    National Research Council Canada - National Science Library

    Osweiler, Victor P

    2006-01-01

    This thesis investigates NORAD two-line element sets (TLE) containing satellite mean orbital elements for the purpose of estimating a covariance matrix and formulating an autocorrelation relationship...

  13. Nanoscale orientation and lateral organization of chimeric metal-binding green fluorescent protein on lipid membrane determined by epifluorescence and atomic force microscopy

    International Nuclear Information System (INIS)

    Prachayasittikul, Virapong; Isarankura Na Ayudhya, Chartchalerm; Tantimongcolwat, Tanawut; Galla, Hans-Joachim

    2005-01-01

    Epifluorescence microscopy as well as atomic force microscopy was successfully applied to explore the orientation and lateral organization of a group of chimeric green fluorescent proteins (GFPs) on lipid membrane. Incorporation of the chimeric GFP carrying Cd-binding region (His6CdBP4GFP) to the fluid phase of DPPC monolayer resulted in a strong fluorescence intensity at the air-water interface. Meanwhile, non-specific adsorption of the GFP having hexahistidine (His6GFP) led to the perturbation of the protein structure in which very low fluorescence was observed. Specific binding of both of the chimeric GFPs to immobilized zinc ions underneath the metal-chelating lipid membrane was revealed. This specific binding could be reversibly controlled by addition of metal ions or metal chelator. Binding of the chimeric GFPs to the metal-chelating lipid membrane was proven to be the end-on orientation while the side-on adsorption was contrarily noted in the absence of metal ions. Increase of lateral mobility owing to the fluidization effect on the chelating lipid membrane subsequently facilitated crystal formation. All these findings have opened up a potential approach for a specific orientation of immobilization of protein at the membrane interface. This could have accounted for a better opportunity of sensor development

  14. 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 fo...

  15. Determination of lead associated with airborne particulate matter by flame atomic absorption and wave-length dispersive x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Talebi, S.M.

    1997-01-01

    The lead content of airborne particulate matter was determined by flame atomic absorption spectrometry (FAAS) following digestion with a mixture of nitric acid and hydrogen peroxide and also by wave-length dispersive x-ray fluorescence (WDXRF). The extraction procedure was checked by analyzing a standard reference material of airborne particulate matter (NIST, SRM -1648). It was concluded that lead can quantitatively (98%) be extracted from airborne particulate matter by the leaching process. A five-stage sequential extraction was performed to assess the potential mobility of lead associated with airborne particulate matter. Comparison of the airborne particulate lead measured by WDXRF to that measured by FAAS showed good agreement. The WDXRF method requires no time-consuming sample preparation or use of environmentally unfriendly solvents. The technique is suggested for direct determination of lead in airborne particulate matter in air pollution studies. (author)

  16. 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

  17. Hydride generation atomic fluorescence spectrometric determination of As, Bi, Sb, Se(IV) and Te(IV) in aqua regia extracts from atmospheric particulate matter using multivariate optimization

    International Nuclear Information System (INIS)

    Moscoso-Perez, Carmen; Moreda-Pineiro, Jorge; Lopez-Mahia, Purificacion; Muniategui-Lorenzo, Soledad; Fernandez-Fernandez, Esther; Prada-Rodriguez, Dario

    2004-01-01

    A highly sensitive and simple method, based on hydride generation and atomic fluorescence detection, has been developed for the determination of As, Bi, Sb, Se(IV) and Te(IV) in aqua regia extracts from atmospheric particulate matter samples. Atmospheric particulates matter was collected on glass fiber filters using a medium volume sampler (PM1 particulate matter). Two-level factorial designs have been used to optimise the hydride generation atomic fluorescence spectrometry (HG-AFS) procedure. The effects of several parameters affecting the hydride generation efficiency (hydrochloric acid, sodium tetrahydroborate and potassium iodide concentrations and flow rates) have been evaluated using a Plackett-Burman experimental design. In addition, parameters affecting the hydride measurement (delay, analysis and memory times) have been also investigated. The significant parameters obtained (sodium tetrahydroborate concentration, sodium tetrahydroborate flow rate and analysis time for As; hydrochloric acid concentration and sodium tetrahydroborate flow rate for Se(IV); and sodium tetrahydroborate concentration and sodium tetrahydroborate flow rate for Te(IV)) have been optimized by using 2 n + star central composite design. Hydrochloric acid concentration and sodium tetrahydroborate flow rate were the significant parameters obtained for Sb and Bi determination, respectively. Using a univariate approach these parameters were optimized. The accuracy of methods have been verified by using several certified reference materials: SRM 1648 (urban particulate matter) and SRM 1649a (urban dust). Detection limits in the range of 6 x 10 -3 to 0.2 ng m -3 have been achieved. The developed methods were applied to several atmospheric particulate matter samples corresponding to A Coruna city (NW Spain)

  18. Non-chromatographic speciation analysis of mercury by flow injection on-line preconcentration in combination with chemical vapor generation atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Wu Hong [School of Chemistry and Chemical Engineering, State Key Laboratory of Coordination Chemistry and Key Laboratory of MOE for Life Science, Nanjing University, Nanjing 210093 (China); Department of Chemistry, Xuzhou Normal University, Xuzhou 221116 (China); Jin Yan [School of Chemistry and Chemical Engineering, State Key Laboratory of Coordination Chemistry and Key Laboratory of MOE for Life Science, Nanjing University, Nanjing 210093 (China); Han Weiying [School of Chemistry and Chemical Engineering, State Key Laboratory of Coordination Chemistry and Key Laboratory of MOE for Life Science, Nanjing University, Nanjing 210093 (China); Miao, Qiang [School of Chemistry and Chemical Engineering, State Key Laboratory of Coordination Chemistry and Key Laboratory of MOE for Life Science, Nanjing University, Nanjing 210093 (China); Bi Shuping [School of Chemistry and Chemical Engineering, State Key Laboratory of Coordination Chemistry and Key Laboratory of MOE for Life Science, Nanjing University, Nanjing 210093 (China)]. E-mail: bisp@nju.edu.cn

    2006-07-15

    A novel non-chromatographic approach for direct speciation of mercury, based on the selective retention inorganic mercury and methylmercury on the inner wall of a knotted reactor by using ammonium diethyl dithiophosphate and dithizone as complexing agents respectively, was developed for flow injection on-line sorption preconcentration coupled with chemical vapor generation non-dispersive atomic fluorescence spectrometry. With the sample pH kept at 2.0, the preconcentration of inorganic mercury on the inner walls of the knotted reactor was carried out based on the exclusive retention of Hg-DDP complex in the presence of methylmercury via on-line merging the sample solution with ammonium diethyl dithiophosphate solution, and selective preconcentration methylmercury was achieved with dithizone instead of ammonium diethyl dithiophosphate. A 15% (v/v) HCl was introduced to elute the retained mercury species and merge with KBH{sub 4} solution for atomic fluorescence spectrometry detection. Under the optimal experimental conditions, the sample throughputs of inorganic mercury and methylmercury were 30 and 20 h{sup -1} with the enhancement factors of 13 and 24. The detection limits were found to be 3.6 ng l{sup -1} for Hg{sup 2+} and 2.0 ng l{sup -1} for CH{sub 3}Hg{sup +}. The precisions (RSD) for the 11 replicate measurements of each 0.2 {mu}g l{sup -1} of Hg{sup 2+} and CH{sub 3}Hg{sup +} were 2.2% and 2.8%, respectively. The developed method was validated by the analysis of certified reference materials (simulated natural water, rice flour and pork) and by recovery measurements on spiked samples, and was applied to the determination of inorganic mercury and methylmercury in biological and environmental water samples.

  19. An on-line system using ion-imprinted polymer for preconcentration and determination of bismuth in seawater employing atomic fluorescence spectrometry.

    Science.gov (United States)

    Felix, Caio S A; Silva, Darllen G; Andrade, Heloysa M C; Riatto, Valeria B; Victor, Mauricio M; Ferreira, Sergio L C

    2018-07-01

    This work proposes an on-line preconcentration system using ion-imprinted polymer (IIP) for determination of bismuth in seawater employing atomic fluorescence spectrometry (AFS). The polymer was synthesized using 2- (5-bromo-2-pyridylazo) -5-diethylaminophenol (Br-PADAP) for complex formation, ethylene glycol dimethacrylate (EGDMA), cross-linking reagent and methacrylic acid (AMA) reagents, used as the functional monomer, 2,2-azobisisobutyronitrile was used as the radical initiator. The polymer was characterized employing the Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The determination of bismuth was performed employing hydride generation atomic fluorescence spectrometry (HG AFS) and the experimental conditions were optimized using a Box Behnken design involving the factors sample pH, eluent concentration and sodium tetrahydroborate concentration. So, using the optimized conditions the system allows the determination of bismuth with limits of detection and quantification of 26 and 88 ng L -1 , a preconcentration factor of 19.8. All these parameters were determined using a sample volume of 25 mL. The precision expressed as relative standard deviation (RSD%) was 3.7% for a bismuth(III) solution of concentration 0.25 µg L -1 . The system proposed was applied for the determination of bismuth in four seawater samples collected in Salvador City, Bahia State, Brazil. The concentrations obtained varied from 0.38 to 0.45 μg L -1 . The accuracy was evaluated by addition/recovery test, and the recoveries found varied from 92% to 101%. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Non-chromatographic speciation analysis of mercury by flow injection on-line preconcentration in combination with chemical vapor generation atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    Wu Hong; Jin Yan; Han Weiying; Miao, Qiang; Bi Shuping

    2006-01-01

    A novel non-chromatographic approach for direct speciation of mercury, based on the selective retention inorganic mercury and methylmercury on the inner wall of a knotted reactor by using ammonium diethyl dithiophosphate and dithizone as complexing agents respectively, was developed for flow injection on-line sorption preconcentration coupled with chemical vapor generation non-dispersive atomic fluorescence spectrometry. With the sample pH kept at 2.0, the preconcentration of inorganic mercury on the inner walls of the knotted reactor was carried out based on the exclusive retention of Hg-DDP complex in the presence of methylmercury via on-line merging the sample solution with ammonium diethyl dithiophosphate solution, and selective preconcentration methylmercury was achieved with dithizone instead of ammonium diethyl dithiophosphate. A 15% (v/v) HCl was introduced to elute the retained mercury species and merge with KBH 4 solution for atomic fluorescence spectrometry detection. Under the optimal experimental conditions, the sample throughputs of inorganic mercury and methylmercury were 30 and 20 h -1 with the enhancement factors of 13 and 24. The detection limits were found to be 3.6 ng l -1 for Hg 2+ and 2.0 ng l -1 for CH 3 Hg + . The precisions (RSD) for the 11 replicate measurements of each 0.2 μg l -1 of Hg 2+ and CH 3 Hg + were 2.2% and 2.8%, respectively. The developed method was validated by the analysis of certified reference materials (simulated natural water, rice flour and pork) and by recovery measurements on spiked samples, and was applied to the determination of inorganic mercury and methylmercury in biological and environmental water samples

  1. Study of the atomic dynamics of nanoclusters Y2SiO5:Pr3+ by the confocal fluorescent microscopy

    International Nuclear Information System (INIS)

    Malyukin, Yu.V.; Zhmurin, P.N.; Syrkin, E.S.; Feodosyev, S.B.; Mamalui, M.A.

    2004-01-01

    The system under consideration consists of a Pr 3+ ion placed into a nanodimensional Y 2 SiO 5 crystal (∝20 nm), which rests on a glass substrate. The spectrum and attenuation of the fluorescence of the Pr 3+ ion have been studied by the method of confocal fluorescent microscopy. The rapid electron relaxation in J-multiplets of rare earth impurity ions split by the crystal field (for a usual bulk crystal τ∝10 -9 -10 -12 sec) is shown to be suppressed in the nanodimensional crystal of Y 2 SiO 5 :Pr 3+ . For the excited Stark components of 1 D 2 multiplet, the electron relaxation appears to be more than 10 4 times suppressed, while an average splitting of the 1 D 2 multiplet by the crystal field of ligands is 200 cm -1 . The observed phenomena strongly depends on the interaction of the Y 2 SiO 5 :Pr 3+ cluster with the substrate and the surrounding ('matrix'). Experimental results and theoretical calculations show the noticeable changes in the structure of vibrational spectrum and the density of vibrational states of the nanodimensional Y 2 SiO 5 :Pr 3+ crystal. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Major constituent quantitative determination in uranium alloys by coupled plasma atomic emission spectrometry and X ray fluorescence wavelength dispersive spectrometry

    International Nuclear Information System (INIS)

    Oliveira, Luis Claudio de; Silva, Adriana Mascarenhas Martins da; Gomide, Ricardo Goncalves; Silva, Ieda de Souza

    2013-01-01

    A wavelength-dispersive X-ray fluorescence (WD-XRF) spectrometric method for determination of major constituents elements (Zr, Nb, Mo) in Uranium/Zirconium/Niobium and Uranium/Molybdenum alloy samples were developed. The methods use samples taken in the form of chips that were dissolved in hot nitric acid and precipitate particles melted with lithium tetraborate and dissolved in hot nitric acid and finally analyzed as a solution. Studies on the determination by inductively coupled plasma optic emission spectrometry (ICP OES) using matched matrix in calibration curve were developed. The same samples solution were analyzed in both methods. The limits of detection (LOD), linearity of the calibrations curves, recovery study, accuracy and precision of the both techniques were carried out. The results were compared. (author)

  3. Induction of chromosome aberrations in two lines of cultured cells using different types of radiation

    International Nuclear Information System (INIS)

    Zoetelief, J.; Dingjan-Hirschi, E.S.; Hasper, J.; Janse, H.C.; Barendsen, G.W.

    The induction of chromosome aberrations has been investigated in two lines of cultured cells for different types of radiation. The obtained results are compared with information on induction of cell reproductive death and malignant transformation. (Auth.)

  4. [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

  5. 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)

    Mao, Xuefei; Qi, Yuehan; Huang, Junwei; Liu, Jixin; Chen, Guoying; Na, Xing; Wang, Min; Qian, Yongzhong

    2016-04-05

    A novel dielectric barrier discharge reactor (DBDR) was utilized to trap/release arsenic coupled to hydride generation atomic fluorescence spectrometry (HG-AFS). On the DBD principle, the precise and accurate control of trap/release procedures was fulfilled at ambient temperature, and an analytical method was established for ultratrace arsenic in real samples. Moreover, the effects of voltage, oxygen, hydrogen, and water vapor on trapping and releasing arsenic by DBDR were investigated. For trapping, arsenic could be completely trapped in DBDR at 40 mL/min of O2 input mixed with 600 mL/min Ar carrier gas and 9.2 kV discharge potential; prior to release, the Ar carrier gas input should be changed from the upstream gas liquid separator (GLS) to the downstream GLS and kept for 180 s to eliminate possible water vapor interference; for arsenic release, O2 was replaced by 200 mL/min H2 and discharge potential was adjusted to 9.5 kV. Under optimized conditions, arsenic could be detected as low as 1.0 ng/L with an 8-fold enrichment factor; the linearity of calibration reached R(2) > 0.995 in the 0.05 μg/L-5 μg/L range. The mean spiked recoveries for tap, river, lake, and seawater samples were 98% to 103%; and the measured values of the CRMs including GSB-Z50004-200431, GBW08605, and GBW(E)080390 were in good agreement with the certified values. These findings proved the feasibility of DBDR as an arsenic preconcentration tool for atomic spectrometric instrumentation and arsenic recycling in industrial waste gas discharge.

  6. 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.

  7. Interaction analysis of chimeric metal-binding green fluorescent protein and artificial solid-supported lipid membrane by quartz crystal microbalance and atomic force microscopy

    International Nuclear Information System (INIS)

    Prachayasittikul, Virapong; Na Ayudhya, Chartchalerm Isarankura; Hilterhaus, Lutz; Hinz, Andreas; Tantimongcolwat, Tanawut; Galla, Hans-Joachim

    2005-01-01

    Non-specific adsorption and specific interaction between a chimeric green fluorescent protein (GFP) carrying metal-binding region and the immobilized zinc ions on artificial solid-supported lipid membranes was investigated using the quartz crystal microbalance technique and the atomic force microscopy (AFM). Supported lipid bilayer, composed of octanethiol and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-[N- (5-amino-1-carboxypentyl iminodiacetic acid)succinyl] (NTA-DOGS)-Zn 2+ , was formed on the gold electrode of quartz resonator (5 MHz). Binding of the chimeric GFP to zinc ions resulted in a rapid decrease of resonance frequency. Reversibility of the process was demonstrated via the removal of metal ions by EDTA. Nanoscale structural orientation of the chimeric GFP on the membrane was imaged by AFM. Association constant of the specific binding to metal ions was 2- to 3-fold higher than that of the non-specific adsorption, which was caused by the fluidization effect of the metal-chelating lipid molecules as well as the steric hindrance effect. This infers a possibility for a further development of biofunctionalized membrane. However, maximization is needed in order to attain closer advancement to a membrane-based sensor device

  8. 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.

  9. Mercury speciation in thawed out and refrozen fish samples by gas chromatography coupled to inductively coupled plasma mass spectrometry and atomic fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Krystek, Petra; Ritsema, Rob [National Institute for Public Health and the Environment (RIVM), Laboratory for Analytical Chemistry, Bilthoven (Netherlands)

    2005-01-01

    Different sub-sampling procedures were applied for the determination of mercury species (as total mercury Hg, methylmercury MeHg{sup +} and inorganic mercury Hg{sup 2+}) in frozen fish meat. Analyses were carried out by two different techniques. After the sample material was pre-treated by microwave digestion, atomic fluorescence spectroscopy (AFS) was used for the determination of total Hg. Speciation analysis was performed according to the following procedure: dissolution of sample material in tetramethylammonium hydroxide (TMAH), derivatisation with sodium tetraethylborate (NaBEt{sub 4}), extraction into isooctane and measurement with gas chromatography inductively coupled plasma mass spectrometry (GC-ICPMS) for the identification and quantification of methylmercury (MeHg{sup +}) and inorganic mercury (Hg{sup 2+}). The concentration range of total Hg measured in the shark fillets is between 0.9 and 3.6 {mu}g g{sup -1} thawed out shark fillet. Speciation analysis leads to {>=}94% Hg present as MeHg{sup +}. Homogeneity, storage conditions and stability of analytical species and sample materials have great influence on analytical results. Sub-sampling of half-frozen/partly thawed out fish and analysis lead to significantly different concentrations, which are on average a factor of two lower. (orig.)

  10. Distribution of heavy metals in Lumbricus terrestris, Aporrectodea longa and A. rosea measured by atomic absorption and X-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Andersen, C.; Laursen, J.

    1982-01-01

    Distribution of Ca, Pb, Cd, Zn, Fe and Mn has been investigated in the earthworm species Lumbricus terrestris, Aporectodea longa and A. rosea by atomic absorption and X-ray fluorescence spectrometry measurements. The material of L. terrestris originated from the garden of the Royal Veterinary and Agricultural University in central Copenhagen. Material of the other two species was sampled in sewage sludge treated plots. It was found that lead and cadmium are accumulated in the gut wall and from here transferred to waste nodules (brown bodies). In L. terrestris more lead was transferred to waste nodules than cadmium. Also large amounts of zinc were accumulated in the gut wall. Analyses of L. terrestris calciferous glands showed that these take part in regulation and excretion of a number of heavy metals. Lead and cadmium content was low in the ventral nerve chord and seminal vesicles. A. longa with poorly developed calciferous glands seems to rely more on waste nodule formation in the ultimate immobilization of lead. (author)

  11. Determination of As in tobacco by using electrochemical hydride generation at a Nafion® solid polymer electrolyte cell hyphenated with atomic fluorescence spectrometry

    Science.gov (United States)

    Yang, Qinghua; Gan, Wuer; Deng, Yun; Sun, Huihui

    2011-11-01

    In the present work, a novel solid polymer electrolyte hydride generation (SPE-HG) cell was developed. The home-made SPE-HG cell, mainly composed of three components (Nafion®117 membrane for separating and H + exchanging, a soft graphite felt cathode and a Ti mesh modified by Ir anode), was employed for detecting As by coupling to atomic fluorescence spectrometry (AFS). The H + generated by electrolysis of pure water in anode chamber transferred to cathode chamber through SPE, and immediately reacted with As 3 + to generate AsH 3. The relative mechanisms and operation conditions for hydride generation of As were investigated in detail. The developed cell employed water as an alternative of acid anolyte, with virtues of low-cost, more than 6 months lifetime and environment friendly compared with the conventional cell. Under the optimized conditions, the limit of determination of As 3 + for sample blank solution was 0.12 μg L - 1 , the RSD was 2.9% for 10 consecutive measurements of 5 μg L - 1 As 3 + standard solution. The accuracy of the method was verified by the determination of As in the reference Tea (GBW07605) and the developed method was successfully applied to determine trace amounts of As in tobacco samples with recovery from 97% to 103%.

  12. 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.)

  13. 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.

  14. Determination of arsenic species in seafood samples from the Aegean Sea by liquid chromatography-(photo-oxidation)-hydride generation-atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Schaeffer, Richard [Department of Applied Chemistry, Corvinus University, Villanyi ut 29-35, 1118 Budapest (Hungary); Soeroes, Csilla [Department of Applied Chemistry, Corvinus University, Villanyi ut 29-35, 1118 Budapest (Hungary); Ipolyi, Ildiko [Department of Applied Chemistry, Corvinus University, Villanyi ut 29-35, 1118 Budapest (Hungary); Fodor, Peter [Department of Applied Chemistry, Corvinus University, Villanyi ut 29-35, 1118 Budapest (Hungary); Thomaidis, Nikolaos S. [Laboratory of Analytical Chemistry, Department of Chemistry, University of Athens, Panepistiomopolis Zografou, 15776 Athens (Greece)]. E-mail: ntho@chem.uoa.gr

    2005-08-15

    In this study arsenic compounds were determined in mussels (Mytulis galloprovincialis), anchovies (Engraulis encrasicholus), sea-breams (Sparus aurata), sea bass (Dicentrarchus labrax) and sardines (Sardina pilchardus) collected from Aegean Sea using liquid chromatography-photo-oxidation-hydride generation-atomic fluorescence spectrometry [LC-(PO)-HG-AFS] system. Twelve arsenicals were separated and determined on the basis of their difference in two properties: (i) the pK {sub a} values and (ii) hydride generation capacity. The separation was carried out both with an anion- and a cation-exchange column, with and without photo-oxidation. In all the samples arsenobetaine, AB was detected as the major compound (concentrations ranging between 2.7 and 23.1 {mu}g g{sup -1} dry weight), with trace amounts of arsenite, As(III), dimethylarsinic acid, DMA and arsenocholine, AC, also present. Arsenosugars were detected only in the mussel samples (in concentrations of 0.9-3.6 {mu}g g{sup -1} dry weight), along with the presence of an unknown compound, which, based on its retention time on the anion-exchange column Hamilton PRP-X100 and a recent communication [E. Schmeisser, R. Raml, K.A. Francesconi, D. Kuehnelt, A. Lindberg, Cs. Soeroes, W. Goessler, Chem. Commun. 16 (2004) 1824], is supposed to be a thio-arsenic analogue.

  15. Analysis of heavy metals and minerals elements in the turmeric using Total-Reflection X-ray Fluorescence analysis technique and Atomic Absorption Spectrometry

    International Nuclear Information System (INIS)

    Andriamisetra, V.M.Z.

    2014-01-01

    Currently, many studies demonstrate anti-cancer and anti-inflammatory benefits of turmeric. The aims of this work is to perform analysis of metals such as calcium, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, bromine, rubidium, strontium, cadmium and lead in the turmeric collected from various places in Madagascar. The analysis by total reflection X-ray fluorescence technique is used to determine the concentrations of heavy metals, while the atomic absorption spectrometry is used for the determination of trace elements. Analysis results show that the concentration of calcium in the turmeric is very high, its average concentration is 1025.8 mg.kg -1 . The average concentrations of manganese, of copper and of iron are respectively 44.7 mg.kg -1 ; 19.7 mg.kg -1 and 53.6 mg.kg -1 . The average concentrations of zinc, of rubidium and of strontium are respectively 17.3 mg.kg -1 ; 35.2 mg.kg -1 and 21.7 mg.kg -1 [fr

  16. Synergetic enhancement effect of ionic liquid and diethyldithiocarbamate on the chemical vapor generation of nickel for its atomic fluorescence spectrometric determination in biological samples

    International Nuclear Information System (INIS)

    Zhang Chuan; Li Yan; Wu Peng; Yan Xiuping

    2009-01-01

    Room-temperature ionic liquid in combination with sodium diethyldithiocarbamate (DDTC) was used to synergetically improve the chemical vapor generation (CVG) of nickel. Volatile species of nickel were effectively generated through reduction of acidified analyte solution with KBH 4 in the presence of 0.02% DDTC and 25 mmol L -1 1-butyl-3-methylimidazolium bromide ([C 4 mim]Br) at room temperature. Thus, a new flow injection (FI)-CVG-atomic fluorescence spectrometric (FI-CVG-AFS) method was developed for determination of nickel with a detection limit of 0.65 μg L -1 (3 s) and a sampling frequency of 180 h -1 . With consumption of 0.5 mL sample solution, an enhancement factor of 2400 was obtained. The precision (RSD) for eleven replicate determinations of 20 μg L -1 Ni was 3.4%. The developed FI-CVG-AFS method was successfully applied to determination of trace Ni in several certified biological reference materials.

  17. 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%. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. 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.

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

    International Nuclear Information System (INIS)

    Mou, C.-Y.; Yuan, W.-L.; Tsai, I-S.; O'Rear, Edgar A.; Barraza, Harry

    2008-01-01

    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 -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 -11 S and 7.7 x 10 -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 -3 S/cm and 2.6 x 10 -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

  20. Investigation of Al2O3 barrier film properties made by atomic layer deposition onto fluorescent tris-(8-hydroxyquinoline) aluminium molecular films

    International Nuclear Information System (INIS)

    Maindron, Tony; Aventurier, Bernard; Ghazouani, Ahlem; Jullien, Tony; Rochat, Névine; Simon, Jean-Yves; Viasnoff, Emilie

    2013-01-01

    Al 2 O 3 films have been deposited at 85 °C by atomic layer deposition onto single 100 nm thick tris-(8-hydroxyquinoline) aluminium (AlQ 3 ) films made onto silicon wafers. It has been found that a thick ALD-deposited Al 2 O 3 layer (> 11 nm) greatly prevents the photo-oxidation of AlQ 3 films when exposed to continuous UV irradiation (350 mW/cm 2 ). Thin Al 2 O 3 thicknesses (< 11 nm) on the contrary yield lower barrier performances. Defects in the Al 2 O 3 layer have been easily observed as non-fluorescent AlQ 3 singularities, or black spots, under UV light on the system Si/AlQ 3 /Al 2 O 3 stored into laboratory conditions (22 °C/50% Relative Humidity (RH)) for long time scale (∼ 2000 h). Accelerated aging conditions in a climatic chamber (85 °C/85% RH) also allow faster visualization of the same defects (168 h). The black spot density grows upon time and the black spot density occurrence rates have been calculated to be 0.024 h −1 ·cm −2 and 0.243 h −1 ·cm −2 respectively for the two testing conditions. A detailed investigation of these defects did show that they cannot be ascribed to the presence of a detectable particle. In that sense they are presumably the consequence of the existence of nanometre-scaled defects which cannot be detected onto fresh samples. Interestingly, an additional overcoating of ebeam-deposited SiO 2 onto the Si/AlQ 3 /Al 2 O 3 sample helps to decrease drastically the black spot density occurrence rates down to 0.004 h −1 ·cm −2 and 0.04 h −1 ·cm −2 respectively for 22 °C/50% RH and 85 °C/85% RH testing conditions. These observations highlight the moisture sensitivity of low temperature ALD-deposited Al 2 O 3 films and confirm the general idea that a single Al 2 O 3 ALD film performs as an ultra-high barrier but needs to be overprotected from water condensation by an additional moisture-stable layer. - Highlights: • Thin Al 2 O 3 films have been deposited by atomic layer deposition onto organic films.

  1. Selective determination of four arsenic species in rice and water samples by modified graphite electrode-based electrolytic hydride generation coupled with atomic fluorescence spectrometry.

    Science.gov (United States)

    Yang, Xin-An; Lu, Xiao-Ping; Liu, Lin; Chi, Miao-Bin; Hu, Hui-Hui; Zhang, Wang-Bing

    2016-10-01

    This work describes a novel non-chromatographic approach for the accurate and selective determining As species by modified graphite electrode-based electrolytic hydride generation (EHG) for sample introduction coupled with atomic fluorescence spectrometry (AFS) detection. Two kinds of sulfydryl-containing modifiers, l-cysteine (Cys) and glutathione (GSH), are used to modify cathode. The EHG performance of As has been changed greatly at the modified cathode, which has never been reported. Arsenite [As(III)] on the GSH modified graphite electrode (GSH/GE)-based EHG can be selectively and quantitatively converted to AsH3 at applied current of 0.4A. As(III) and arsenate [As(V)] on the Cys modified graphite electrode (Cys/GE) EHG can be selectively and efficiently converted to arsine at applied current of 0.6A, whereas monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) do not form any or only less volatile hydrides under this condition. By changing the analytical conditions, we also have achieved the analysis of total As (tAs) and DMA. Under the optimal condition, the detection limits (3s) of As(III), iAs and tAs in aqueous solutions are 0.25μgL(-1), 0.22μgL(-1) and 0.10μgL(-1), respectively. The accuracy of the method is verified through the analysis of standard reference materials (SRM 1568a). Copyright © 2016 Elsevier B.V. All rights reserved.

  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. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. 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}.

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

    International Nuclear Information System (INIS)

    Campanella, Beatrice; Onor, Massimo; Mascherpa, Marco Carlo; D’Ulivo, Alessandro; Ferrari, Carlo; Bramanti, Emilia

    2013-01-01

    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 II . •Each measure requires less than 5 min with a LOD of 3 ng mL −1 (as mercury). •Hg concentration in commercial ophthalmic solutions ranges between 7.5 and 59.0 μg mL −1 . -- Abstract: We developed a flow injection (FI) method for the determination of thiomersal (sodium ethylmercurithiosalicylate, C 9 H 9 HgNaO 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 4 solution, and AFS detection in an Ar/H 2 miniaturized flame. The method was linear in the 0.01–2 μg mL −1 range, with a LOD of 0.003 μg mL −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 −1

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

    International Nuclear Information System (INIS)

    García-Salgado, S.; Quijano, M.A.; Bonilla, M.M.

    2012-01-01

    Highlights: ► Total As and As species were analyzed in edible marine algae. ► A microwave-assisted extraction method with deionized water was applied. ► As compounds identified comprised DMA, As(V) and four arsenosugars ► 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 μg g −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 μg g −1 , whereas sulfonate and sulfate sugars were only detected in three of them (0.6-7.2 μg g −1 ). Regarding arsenic toxic species, low concentration levels of dimethylarsinic acid (DMA) ( −1 ) and generally high arsenate (As(V)) concentrations (up to 77 μg g −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.

  7. Determination of inorganic arsenic in algae using bromine halogenation and on-line nonpolar solid phase extraction followed by hydride generation atomic fluorescence spectrometry.

    Science.gov (United States)

    Zhang, Weihong; Qi, Yuehan; Qin, Deyuan; Liu, Jixin; Mao, Xuefei; Chen, Guoying; Wei, Chao; Qian, Yongzhong

    2017-08-01

    Accurate, stable and fast analysis of toxic inorganic arsenic (iAs) in complicated and arsenosugar-rich algae matrix is always a challenge. Herein, a novel analytical method for iAs in algae was reported, using bromine halogenation and on-line nonpolar solid phase extraction (SPE) followed by hydride generation atomic fluorescence spectrometry (HG-AFS). The separation of iAs from algae was first performed by nonpolar SPE sorbent using Br - for arsenic halogenation. Algae samples were extracted with 1% perchloric acid. Then, 1.5mL extract was reduced by 1% thiourea, and simultaneously reacted (for 30min) with 50μL of 10% KBr for converting iAs to AsBr 3 after adding 3.5mL of 70% HCl to 5mL. A polystyrene (PS) resin cartridge was employed to retain arsenicals, which were hydrolyzed, eluted from the PS resin with H 2 O, and categorized as iAs. The total iAs was quantified by HG-AFS. Under optimum conditions, the spiked recoveries of iAs in real algae samples were in the 82-96% range, and the method achieved a desirable limit of detection of 3μgkg -1 . The inter-day relative standard deviations were 4.5% and 4.1% for spiked 100 and 500μgkg -1 respectively, which proved acceptable for this method. For real algae samples analysis, the highest presence of iAs was found in sargassum fusiforme, followed by kelp, seaweed and laver. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. 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.

  9. Determination of trace cadmium in rice by liquid spray dielectric barrier discharge induced plasma - chemical vapor generation coupled with atomic fluorescence spectrometry

    Science.gov (United States)

    Liu, Xing; Zhu, Zhenli; Bao, Zhengyu; Zheng, Hongtao; Hu, Shenghong

    2018-03-01

    Cadmium contamination in rice has become an increasing concern in many countries including China. A simple, cost-effective, and highly sensitive method was developed for the determination of trace cadmium in rice samples based on a new high-efficient liquid spray dielectric barrier discharge induced plasma (LSDBD) vapor generation coupled with atomic fluorescence spectrometry (AFS). The analytical procedure involves the efficient formation of Cd volatile species by LSDBD plasma induced chemical processes without the use of any reducing reagents (Na/KBH4 in conventional hydride generation). The effects of the addition of organic substances, different discharge parameters such as discharge voltage and discharge gap, as well as the foreign ion interferences were investigated. Under optimized conditions, a detection limit of 0.01 μg L- 1 and a precision of 0.8% (RSD, n = 5, 1 μg L- 1 Cd) was readily achieved. The calibration curve was linear in the range between 0.1 and 10 μg L- 1, with a correlation coefficient of R2 = 0.9995. Compared with the conventional acid-BH4- vapor generation, the proposed method not only eliminates the use of unstable and expensive reagents, but also offers high tolerance for coexisting ions, which is well suited to the direct analysis of environmental samples. The validation of the proposed method was demonstrated by the analysis of Cd in reference material of rice (GBW080684). It was also successfully applied to the determination of trace cadmium in locally collected 11 rice samples, and the obtained Cd concentrations are ranged from 7.2 to 517.7 μg kg- 1.

  10. Highly sensitive and interference-free determination of bismuth in environmental samples by electrothermal vaporization atomic fluorescence spectrometry after hydride trapping on iridium-coated tungsten coil

    International Nuclear Information System (INIS)

    Liu Rui; Wu Peng; Xu Kailai; Lv Yi; Hou Xiandeng

    2008-01-01

    Bismuthine was on-line trapped on tungsten coil and subsequently electrothermally vaporized for the determination by atomic fluorescence spectrometry (AFS). Several noble metals, including Pd, Rh, Pt, and Ir, were explored as permanent chemical modifier for tungsten coil on-line trapping. Investigation showed that Ir gave the best performance, in which bismuthine was on-line trapped on Ir-coated tungsten coil at 560 o C, and then released at 1550 o C for subsequent transfer to AFS by a mixture of Ar and H 2 . Under optimum instrumental conditions, the trapping efficiency was found to be 73 ± 3%. With 120 s (12 mL sample volume) trapping time, a limit of detection (LOD) of 4 ng L -1 was obtained, compared to conventional hydride generation AFS (0.09 μg L -1 ); the LOD can be lowered down to 1 ng L -1 by increasing the trapping time to 480 s. The LOD was found to be better or at least comparable to literature levels involving on-line trapping and some other sophisticated instrumental methods such as ICP-MS and GF-AAS. A comprehensive interference study involving conventional hydride-forming elements and some transition metals was carried out, and the result showed that the gas phase interference from other hydride-forming elements was largely reduced, thanks to the use of on-line tungsten coil trapping. Finally, the proposed method was applied to the determination of bismuth in several biological and environmental standard reference materials, and a t-test shows that the analytical results by the proposed method have no significant difference from the certified values at the confidence level of 95%

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

    International Nuclear Information System (INIS)

    Papadopoulou, D.N.; Zachariadis, G.A.; Anthemidis, A.N.; Tsirliganis, N.C.; Stratis, J.A.

    2004-01-01

    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)

  12. 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

    International Nuclear Information System (INIS)

    Margetinova, Jana; Houserova-Pelcova, Pavlina; Kuban, Vlastimil

    2008-01-01

    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 -1 HCl, 50% aqueous methanol and 0.2 mol L -1 citric acid (for masking co-extracted Fe 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 μm) using the same complexation reagent (2-mercaptophenol). The limits of detection were 4.3 μg L -1 for methylmercury (MeHg + ), 1.4 μg L -1 for ethylmercury (EtHg + ), 0.8 μg L -1 for inorganic mercury (Hg 2+ ), 0.8 μg L -1 for phenylmercury (PhHg + )

  13. 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)

  14. Study of parameters of simultaneous lasing on two lines sharing an upper level

    International Nuclear Information System (INIS)

    Pikulev, A A

    2002-01-01

    Stationary lasing at two competing lines sharing an upper level is studied. Based on the expressions for the gain obtained earlier, the possible lasing regimes are considered (at one or two lines) and approximate formulas are derived for determining the output power in each line. These formulas are shown to be the generalisation of the Rigrod formula to the case of simultaneous lasing at several lines. (control of laser radiation parameters)

  15. Defect of focus in two-line resolution with Hanning amplitude filters

    Science.gov (United States)

    Karunasagar, D.; Bhikshamaiah, G.; Keshavulu Goud, M.; Lacha Goud, S.

    In the presence of defocusing the modified Sparrow limits of resolution for two-line objects have been investigated for a diffraction-limited coherent optical system apodized by generalized Hanning amplitude filters. These limits have been studied as a function of different parameters such as intensity ratio, the order of the filter for various amounts of apodization parameter. Results reveal that in some situations the defocusing is effective in enhancing the resolution of an optical system.

  16. Efficient generation of volatile species for cadmium analysis in seafood and rice samples by a modified chemical vapor generation system coupled with atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    Yang, Xin-an; Chi, Miao-bin; Wang, Qing-qing; Zhang, Wang-bing

    2015-01-01

    Highlights: • We develop a modified chemical vapor generation method coupled with AFS for the determination of cadmium. • The response of Cd could be increased at least four-fold compared to conventional thiourea and Co(II) system. • A simple mixing sequences experiment is designed to study the reaction mechanism. • The interference of transition metal ions can be easily eliminated by adding DDTC. • The method is successfully applied in seafood samples and rice samples. - Abstract: A vapor generation procedure to determine Cd by atomic fluorescence spectrometry (AFS) has been established. Volatile species of Cd are generated by following reaction of acidified sample containing Fe(II) and L-cysteine (Cys) with sodium tetrahydroborate (NaBH 4 ). The presence of 5 mg L −1 Fe(II) and 0.05% m/v Cys improves the efficiency of Cd vapor generation substantially about four-fold compared with conventional thiourea and Co(II) system. Three experiments with different mixing sequences and reaction times are designed to study the reaction mechanism. The results document that the stability of Cd(II)–Cys complexes is better than Cys–THB complexes (THB means NaBH 4 ) while the Cys–THB complexes have more contribution to improve the Cd vapor generation efficiency than Cd(II)–Cys complexes. Meanwhile, the adding of Fe(II) can catalyze the Cd vapor generation. Under the optimized conditions, the detection limit of Cd is 0.012 μg L −1 ; relative standard deviations vary between 0.8% and 5.5% for replicate measurements of the standard solution. In the presence of 0.01% DDTC, Cu(II), Pb(II) and Zn(II) have no significant influence up to 5 mg L −1 , 10 mg L −1 and 10 mg L −1 , respectively. The accuracy of the method is verified through analysis of the certificated reference materials and the proposed method has been applied in the determination of Cd in seafood and rice samples

  17. Efficient generation of volatile species for cadmium analysis in seafood and rice samples by a modified chemical vapor generation system coupled with atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xin-an, E-mail: 13087641@qq.com; Chi, Miao-bin, E-mail: 1161306667@qq.com; Wang, Qing-qing, E-mail: wangqq8812@163.com; Zhang, Wang-bing, E-mail: ahutwbzh@163.com

    2015-04-15

    Highlights: • We develop a modified chemical vapor generation method coupled with AFS for the determination of cadmium. • The response of Cd could be increased at least four-fold compared to conventional thiourea and Co(II) system. • A simple mixing sequences experiment is designed to study the reaction mechanism. • The interference of transition metal ions can be easily eliminated by adding DDTC. • The method is successfully applied in seafood samples and rice samples. - Abstract: A vapor generation procedure to determine Cd by atomic fluorescence spectrometry (AFS) has been established. Volatile species of Cd are generated by following reaction of acidified sample containing Fe(II) and L-cysteine (Cys) with sodium tetrahydroborate (NaBH{sub 4}). The presence of 5 mg L{sup −1} Fe(II) and 0.05% m/v Cys improves the efficiency of Cd vapor generation substantially about four-fold compared with conventional thiourea and Co(II) system. Three experiments with different mixing sequences and reaction times are designed to study the reaction mechanism. The results document that the stability of Cd(II)–Cys complexes is better than Cys–THB complexes (THB means NaBH{sub 4}) while the Cys–THB complexes have more contribution to improve the Cd vapor generation efficiency than Cd(II)–Cys complexes. Meanwhile, the adding of Fe(II) can catalyze the Cd vapor generation. Under the optimized conditions, the detection limit of Cd is 0.012 μg L{sup −1}; relative standard deviations vary between 0.8% and 5.5% for replicate measurements of the standard solution. In the presence of 0.01% DDTC, Cu(II), Pb(II) and Zn(II) have no significant influence up to 5 mg L{sup −1}, 10 mg L{sup −1}and 10 mg L{sup −1}, respectively. The accuracy of the method is verified through analysis of the certificated reference materials and the proposed method has been applied in the determination of Cd in seafood and rice samples.

  18. 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

  19. 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.

  20. Investigation of Al{sub 2}O{sub 3} barrier film properties made by atomic layer deposition onto fluorescent tris-(8-hydroxyquinoline) aluminium molecular films

    Energy Technology Data Exchange (ETDEWEB)

    Maindron, Tony; Aventurier, Bernard [LETI/DOPT/SCOOP/Laboratoire des Composants pour la Visualisation, CEA-LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Ghazouani, Ahlem; Jullien, Tony [LETI/DTSI/SDEP/Laboratoire Dépôt Equipe 2, CEA-LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Rochat, Névine [LETI/DTSI/Service de Caractérisation des Matériaux et Composants, CEA-LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France); Simon, Jean-Yves; Viasnoff, Emilie [LETI/DOPT/SCOOP/Laboratoire des Composants pour la Visualisation, CEA-LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble Cedex 9 (France)

    2013-12-02

    Al{sub 2}O{sub 3} films have been deposited at 85 °C by atomic layer deposition onto single 100 nm thick tris-(8-hydroxyquinoline) aluminium (AlQ{sub 3}) films made onto silicon wafers. It has been found that a thick ALD-deposited Al{sub 2}O{sub 3} layer (> 11 nm) greatly prevents the photo-oxidation of AlQ{sub 3} films when exposed to continuous UV irradiation (350 mW/cm{sup 2}). Thin Al{sub 2}O{sub 3} thicknesses (< 11 nm) on the contrary yield lower barrier performances. Defects in the Al{sub 2}O{sub 3} layer have been easily observed as non-fluorescent AlQ{sub 3} singularities, or black spots, under UV light on the system Si/AlQ{sub 3}/Al{sub 2}O{sub 3} stored into laboratory conditions (22 °C/50% Relative Humidity (RH)) for long time scale (∼ 2000 h). Accelerated aging conditions in a climatic chamber (85 °C/85% RH) also allow faster visualization of the same defects (168 h). The black spot density grows upon time and the black spot density occurrence rates have been calculated to be 0.024 h{sup −1}·cm{sup −2} and 0.243 h{sup −1}·cm{sup −2} respectively for the two testing conditions. A detailed investigation of these defects did show that they cannot be ascribed to the presence of a detectable particle. In that sense they are presumably the consequence of the existence of nanometre-scaled defects which cannot be detected onto fresh samples. Interestingly, an additional overcoating of ebeam-deposited SiO{sub 2} onto the Si/AlQ{sub 3}/Al{sub 2}O{sub 3} sample helps to decrease drastically the black spot density occurrence rates down to 0.004 h{sup −1}·cm{sup −2} and 0.04 h{sup −1}·cm{sup −2} respectively for 22 °C/50% RH and 85 °C/85% RH testing conditions. These observations highlight the moisture sensitivity of low temperature ALD-deposited Al{sub 2}O{sub 3} films and confirm the general idea that a single Al{sub 2}O{sub 3} ALD film performs as an ultra-high barrier but needs to be overprotected from water condensation by an

  1. Designing of fluorescent and magnetic imprinted polymer for rapid, selective and sensitive detection of imidacloprid via activators regenerated by the electron transfer-atom transfer radical polymerization (ARGET-ATRP) technique

    Science.gov (United States)

    Kumar, Sunil; Karfa, Paramita; Madhuri, Rashmi; Sharma, Prashant K.

    2018-05-01

    In this work, we report on a dual-behavior electrochemical/optical sensor for sensitive determination of Imidacloprid by fluorescent dye (fluorescein, FL) and imprinted polymer modified europium doped superparamagnetic iron oxide nanoparticles (FL@SPIONs@MIP). The imidacloprid (IMD)-imprinted polymer was directly synthesized on the Eu-SPIONs surface via Activators regenerated by the electron transfer-atom transfer radical polymerization (ARGET-ATRP) technique. Preparation, characterization and application of the prepared FL@SPIONs@MIP were systematically investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), fluorescence spectroscopy and electrochemical techniques. The electrochemical experiments exhibited a remarkable selectivity of the prepared sensor towards IMD. Determination of IMD by the square wave stripping voltammetry method represented a wide linear range of 0.059-0.791 μg L-1 with a detection limit of 0.0125 μg L-1. In addition, the fluorescence method shows a linear range of 0.039-0.942 μg L-1 and LOD of 0.0108 μg L-1. The fluorescence property of prepared FL@SPIONs@MIP was used for rapid, on-spot but selective detection of IMD in real samples. The proposed electrode displayed excellent repeatability and long-term stability and was successfully applied for quantitative and trace level determination of IMD in several real samples.

  2. Proton and electron impact on molecular and atomic oxygen: I. High resolution fluorescence spectra in the visible and VUV spectral range and emission cross-sections for dissociative ionisation and excitation of O2

    International Nuclear Information System (INIS)

    Wilhelmi, O.; Schartner, K.H.

    2000-01-01

    For pt.II see ibid., vol.11, p.45-58, 2000. Molecular oxygen O 2 was dissociated in collisions with protons and electrons in the intermediate velocity range (p + -energies: 17-800 keV, e - -energies: 0.2-2 keV). Fluorescence from excited atomic and singly ionised fragments and from singly ionised molecules was detected in the VUV and in the visible and near UV spectral range. Highly resolved spectra are presented for the VUV (46-131 nm) and the near UV/visible (340-605 nm) spectral range. Absolute emission cross-sections have been determined for dissociative ionisation and excitation leading to fluorescence in the VUV. Results are compared with published data. (orig.)

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

    International Nuclear Information System (INIS)

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

    2010-01-01

    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 >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).

  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. Time resolved laser induced fluorescence on argon intermediate pressure microwave discharges: Measuring the depopulation rates of the 4p and 5p excited levels as induced by electron and atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Palomares, J.M., E-mail: j.m.palomares-linares@tue.nl; Graef, W.A.A.D.; Hübner, S.; Mullen, J.J.A.M. van der, E-mail: jjamvandermullen@gmail.com

    2013-10-01

    The reaction kinetics in the excitation space of Ar is explored by means of Laser Induced Fluorescence (LIF) experiments using the combination of high rep-rate YAG–Dye laser systems with a well defined and easily controllable surfatron induced plasma setup. The high rep-rate favors the photon statistics while the low energy per pulse avoids intrusive plasma laser interactions. An analysis shows that, despite the low energy per pulse, saturation can still be achieved even when the geometrical overlap and spectral overlap are optimal. Out of the various studies that can be performed with this setup we confine the current paper to the study of the direct responses to the laser pump action of three 4p and one 5p levels of the Ar system. By changing the plasma in a controlled way one gets for these levels the rates of electron and atom quenching and therewith the total destruction rates of electron and atom collisions. Comparison with literature shows that the classical hard sphere collision rate derived for hydrogen gives a good description for the observed electron quenching (e-quenching) in Ar whereas for heavy particle quenching (a-quenching) this agreement was only found for the 5p level. An important parameter in the study of electron excitation kinetics is the location of the boundary in the atomic system for which the number of electron collisions per radiative life time equals unity. It is observed that for the Ar system this boundary is positioned lower than what is expected on grounds of H-like formulas. - Highlights: • Time resolved laser induced fluorescence at high repetition rate • Decay times as function of pressure, electron density and temperature • Measurement of total electron atom depopulation rates • Reasonable agreement of electron total rates with hard sphere approximations.

  6. Simultaneous detection of selenium by atomic fluorescence and sulfur by molecular emission by flow-injection hydride generation with on-line reduction for the determination of selenate, sulfate and sulfite

    Energy Technology Data Exchange (ETDEWEB)

    Tyson, J.F., E-mail: tyson@chem.umass.edu [Department of Chemistry, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Palmer, C.D. [Lead Poisoning Trace Elements Laboratory, Wadsworth Center, New York State Department of Health, P.O. Box 509, Empire State Plaza, Albany, NY 12201-0509 (United States)

    2009-10-12

    An inductively coupled plasma atomic fluorescence spectrometry (ICP-AFS) instrument, was modified so that it was capable of monitoring transient chromatographic or flow-injection profiles and that sulfur molecular emission and selenium atomic fluorescence could be monitored simultaneously in an argon-hydrogen diffusion flame on a glass burner. The analytes were introduced as hydrogen selenide and hydrogen sulfide, generated on a flow-injection manifold. Selenate was reduced to hydride-forming selenite by microwave-assisted on-line reaction with hydrochloric acid, and sulfate, or sulfite, was reduced to hydride-forming sulfide by a mixture of hydriodic acid, acetic acid and sodium hypophosphite. The effects of the nature of reducing agent, flow rate, microwave power and coil length were studied. The limit of detection (3 s) for selenium was 10 {mu}g L{sup -1}, and for sulfide was 70 {mu}g L{sup -1} (200-{mu}L injection volume). The calibration was linear for selenium up to 2 mg L{sup -1} and to 10 mg L{sup -1} for sulfide. The throughput was 180 h{sup -1}. The three sulfur species could be differentiated on the basis of reactivity at various microwave powers.

  7. 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

  8. Fluorescence Correlation Spectroscopy Using Octadecylrhodamine B as a Specific Micelle-Binding Fluorescent Tag, Light Scattering and Tapping Mode Atomic Force Microscopy Studies of Amphiphilic Water-Soluble Block Copolymer Micelles

    Czech Academy of Sciences Publication Activity Database

    Humpolíčková, J.; Procházka, K.; Hof, Martin; Tuzar, Zdeněk; Špírková, Milena

    2003-01-01

    Roč. 19, - (2003), s. 4111-4119 ISSN 0743-7463 R&D Projects: GA MŠk LN00A032; GA ČR GA203/01/0536; GA ČR GA203/01/0735 Institutional research plan: CEZ:AV0Z4050913; CEZ:AV0Z4040901 Keywords : fluorescence * spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.098, year: 2003

  9. Carbonate component reduces o,oEDDHA/Fe sorption on two-line ferrihydrite

    Science.gov (United States)

    Yunta, F.; Lucena, J. J.; Smolders, E.

    2012-04-01

    The o,oEDDHA/Fe is the most common and effective iron chelate used as fertilizer in calcareous soils. Several authors have reported that the anionic o,oEDDHA/Fe complex is adsorbed to soil components such as ferrihydrite. The bicarbonate anion may be a competing ion for this sorption, however no studies have yet identified the extent and mechanism of this interaction. The aim of this work was to study the carbonate (bicarbonate + carbonate) effect on EDDHA/Fe adsorption on two-line ferrihydrite. Two-line ferrihydrite was synthetized adding NaOH on a nitrate iron (III) solution up to a final pH to be 8.0 and allowing to age for 22 hours at 20°C. Dialyzed ferrihydrite was characterized by determining specific parameters such as Fe/OH ratio, BET surface, point zero of charge and x-ray diffraction. The sorption was performed at three pH levels (5, 7.5 and 9.5) and three initial carbonate concentrations (from 0 to 2 mM). Initial EDDHA/Fe, ferrihydrite and ionic strength concentrations were adjusted to 0.18 mM, 10 g L-1 and 5 mM respectively. Total dissolved FeEDDHA concentrations were quantified at 480 nm. The o,oEDDHA/Fe isomers (rac-o,oEDDHA/Fe and meso-o,oEDDHA/Fe) were separated and quantified by High Performance Liquid Chromatography (HPLC) fitting a photodiode array detector (PDA). Distribution factor (KD) and sorbed o,oEDDHA/Fe concentration were determined. Actual carbonate concentration was determined using a multi N/C analyzer. Ferrihydrite samples showed a typical XRD pattern of two-line ferrihydrite, two broad peaks at about 35 and 62° respectively. The BET surfaces (two replicates) were 259.2 ± 3.1 m2/g and 256.0 ± 2.5 m2/g. The Point Zero of Salt Effect (PZSE) was 7.9 ± 0.2 as bibliographically supported for all fresh and thus not rigorously de-carbonated ferrihydrite samples. The KD of the o,oEDDHA/Fe increased from 27.4 ± 0.6 to 304 ± 6 l/kg by decreasing pH from 9.5 and 5.0 when no carbonate was added. Increasing equilibrium carbonate

  10. Study on laser atomic spectroscopy

    International Nuclear Information System (INIS)

    Lee, Jong Min; Song, Kyu Seok; Jeong, Do Young; Kim, Chul Joong; Han, Phil Soon

    1992-01-01

    Electric discharge type atomic vaporizer is developed for the spectroscopic study on actinide elements. Laser induced fluorescence study on actinide elements is performed by using this high temperature type atomizer. For the effective photoionization of elements, copper vapor laser pumped dye laser and electron beam heating type atomic vaporizer are built and their characteristics are measured. In addition, resonance ionization mass spectroscopic analysis for lead sample as well as laser induced fluorescence study on uranium sample in solution phase is made. (Author)

  11. 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.

  12. 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)

  13. Effects of metamorphosis on the aquatic escape response of the two-lined salamander (Eurycea bislineata).

    Science.gov (United States)

    Azizi, Emanuel; Landberg, Tobias

    2002-03-01

    Although numerous studies have described the escape kinematics of fishes, little is known about the aquatic escape responses of salamanders. We compare the escape kinematics of larval and adult Eurycea bislineata, the two-lined salamander, to examine the effects of metamorphosis on aquatic escape performance. We hypothesize that shape changes associated with resorption of the larval tail fin at metamorphosis will affect aquatic locomotor performance. Escape responses were recorded using high-speed video, and the effects of life stage and total length on escape kinematics were analyzed statistically using analysis of covariance. Our results show that both larval and adult E. bislineata use a two-stage escape response (similar to the C-starts of fishes) that consists of a preparatory (stage 1) and a propulsive (stage 2) stroke. The duration of both kinematic stages and the distance traveled during stage 2 increased with total length. Both larval and adult E. bislineata had final escape trajectories that were directed away from the stimulus. The main kinematic difference between larvae and adults is that adults exhibit significantly greater maximum curvature during stage 1. Total escape duration and the distance traveled during stage 2 did not differ significantly between larvae and adults. Despite the significantly lower tail aspect ratio of adults, we found no significant decrease in the overall escape performance of adult E. bislineata. Our results suggest that adults may compensate for the decrease in tail aspect ratio by increasing their maximum curvature. These findings do not support the hypothesis that larvae exhibit better locomotor performance than adults as a result of stronger selective pressures on early life stages.

  14. Radiometric dating and quantitative analysis of elements in depth profiles of sediments by means of nuclear physical as well as X-ray fluorescence and atomic emission spectroscopic methods

    International Nuclear Information System (INIS)

    Schoenburg, M.

    1987-01-01

    The measurement of heavy metal concentration in sediments is of great importance for the assessment of water quality. If dating of the different layers of sediment cores is possible, informations about the history of pollution can be inferred. This paper describes the development and practical test of a procedure suitable for the investigation of sediment cores. Both the element analysis and the dating are based on physical methods. For element concentration determination inductively coupled plasma atomic emission spectrometry (ICP), total-reflection X-ray fluorescence analysis (TXRF) and neutron activation analysis (NAA) are used. The techniques are described and compared. For dating radiometric measurements of 210 Pb and 137 Cs are carried out with a coaxial well-type germanium γ-ray detector in a special low-level arrangement. Results of the systematic investigations are presented and a few individual depth profiles are discussed. (orig.) With 34 figs., 20 tabs [de

  15. 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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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 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 2 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. - 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

  16. Single atom oscillations

    International Nuclear Information System (INIS)

    Wiorkowski, P.; Walther, H.

    1990-01-01

    Modern methods of laser spectroscopy allow the study of single atoms or ions in an unperturbed environment. This has opened up interesting new experiments, among them the detailed study of radiation-atom coupling. In this paper, the following two experiments dealing with this problem are reviewed: the single-atom maser and the study of the resonance fluorescence of a single stored ion. The simplest and most fundamental system for studying radiation-matter coupling is a single two-level atom interacting with a single mode of an electromagnetic field in a cavity. This problem received a great deal of attention shortly after the maser was invented

  17. Electrochemical vapor generation of selenium species after online photolysis and reduction by UV-irradiation under nano TiO{sub 2} photocatalysis and its application to selenium speciation by HPLC coupled with atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Jing; Wang, Qiuquan; Huang, Benli [Xiamen University (China). Department of Chemistry; MOE Key Laboratory of Analytical Sciences, Xiamen (China)

    2005-01-01

    An online UV photolysis and UV/TiO{sub 2} photocatalysis reduction device (UV-UV/TiO{sub 2} PCRD) and an electrochemical vapor generation (ECVG) cell have been used for the first time as an interface between high-performance liquid chromatography (HPLC) and atomic fluorescence spectrometry (AFS) for selenium speciation. The newly designed ECVG cell of approximately 115 {mu}L dead volume consists of a carbon fiber cathode and a platinum loop anode; the atomic hydrogen generated on the cathode was used to reduce selenium to vapor species for AFS determination. The noise was greatly reduced compared with that obtained by use of the UV-UV/TiO{sub 2} PCRD-KBH{sub 4}-acid interface. The detection limits obtained for seleno-DL-cystine (SeCys), selenite (Se{sup IV}), seleno-DL-methionine (SeMet), and selenate (Se{sup VI}) were 2.1, 2.9, 4.3, and 3.5 ng mL{sup -1}, respectively. The proposed method was successfully applied to the speciation of selenium in water-soluble extracts of garlic shoots cultured with different selenium species. The results obtained suggested that UV-UV/TiO{sub 2} PCRD-ECVG should be an effective interface between HPLC and AFS for the speciation of elements amenable to vapor generation, and is superior to methods involving KBH{sub 4}. (orig.)

  18. A comparative study on total reflection X-ray fluorescence determination of low atomic number elements in air, helium and vacuum atmospheres using different excitation sources

    Science.gov (United States)

    Misra, N. L.; Kanrar, Buddhadev; Aggarwal, S. K.; Wobrauschek, Peter; Rauwolf, M.; Streli, Christina

    2014-09-01

    A comparison of trace element determinations of low atomic number (Z) elements Na, Mg, Al, P, K and Ca in air, helium and vacuum atmospheres using W Lβ1, Mo Kα and Cr Kα excitations has been made. For Mo Kα and W Lβ1 excitations a Si (Li) detector with beryllium window was used and measurements were performed in air and helium atmospheres. For Cr Kα excitation, a Si (Li) detector with an ultra thin polymer window (UTW) was used and measurements were made in vacuum and air atmospheres. The sensitivities of the elemental X-ray lines were determined using TXRF spectra of standard solutions and processing them by IAEA QXAS program. The elemental concentrations of the elements in other solutions were determined using their TXRF spectra and pre-determined sensitivity values. The study suggests that, using the above experimental set up, Mo Kα excitation is not suited for trace determination of low atomic number element. Excitation by WLβ1 and helium atmosphere, the spectrometer can be used for the determination of elements with Z = 15 (P) and above with fairly good detection limits whereas Cr Kα excitation with ultra thin polymer window and vacuum atmosphere is good for the elements having Z = 11 (Na) and above. The detection limits using this set up vary from 7048 pg for Na to 83 pg for Ti.

  19. Time resolved laser induced fluorescence on argon intermediate pressure microwave discharges: Measuring the depopulation rates of the 4p and 5p excited levels as induced by electron and atom collisions

    Science.gov (United States)

    Palomares, J. M.; Graef, W. A. A. D.; Hübner, S.; van der Mullen, J. J. A. M.

    2013-10-01

    The reaction kinetics in the excitation space of Ar is explored by means of Laser Induced Fluorescence (LIF) experiments using the combination of high rep-rate YAG-Dye laser systems with a well defined and easily controllable surfatron induced plasma setup. The high rep-rate favors the photon statistics while the low energy per pulse avoids intrusive plasma laser interactions. An analysis shows that, despite the low energy per pulse, saturation can still be achieved even when the geometrical overlap and spectral overlap are optimal. Out of the various studies that can be performed with this setup we confine the current paper to the study of the direct responses to the laser pump action of three 4p and one 5p levels of the Ar system. By changing the plasma in a controlled way one gets for these levels the rates of electron and atom quenching and therewith the total destruction rates of electron and atom collisions. Comparison with literature shows that the classical hard sphere collision rate derived for hydrogen gives a good description for the observed electron quenching (e-quenching) in Ar whereas for heavy particle quenching (a-quenching) this agreement was only found for the 5p level. An important parameter in the study of electron excitation kinetics is the location of the boundary in the atomic system for which the number of electron collisions per radiative life time equals unity. It is observed that for the Ar system this boundary is positioned lower than what is expected on grounds of H-like formulas.

  20. THE EVOLUTION OF ATOMIC SPECTROSCOPY IN MEASURING TOXIC CONTAMINANTS

    Science.gov (United States)

    Three decades of study of environmental conditions necessary for the protection of freshwateraquatic life have been limited by the development and application of analytical methodology utilizing atomic adsorption, atomic fluorescence, and atomic emission spectroscopy.The...

  1. Proposal for Testing and Validation of Vacuum Ultra-Violet Atomic Laser-Induced Fluorescence as a Method to Analyze Carbon Grid Erosion in Ion Thrusters

    Science.gov (United States)

    Stevens, Richard

    2003-01-01

    Previous investigation under award NAG3-25 10 sought to determine the best method of LIF to determine the carbon density in a thruster plume. Initial reports from other groups were ambiguous as to the number of carbon clusters that might be present in the plume of a thruster. Carbon clusters would certainly affect the ability to LIF; if they were the dominant species, then perhaps the LIF method should target clusters. The results of quadrupole mass spectroscopy on sputtered carbon determined that minimal numbers of clusters were sputtered from graphite under impact from keV Krypton. There were some investigations in the keV range by other groups that hinted at clusters, but at the time the proposal was presented to NASA, there was no data from low-energy sputtering available. Thus, the proposal sought to develop a method to characterize the population only of atoms sputtered from a graphite target in a test cell. Most of the ground work had been established by the previous two years of investigation. The proposal covering 2003 sought to develop an anti-Stokes Raman shifting cell to generate VUW light and test this cell on two different laser systems, ArF and YAG- pumped dye. The second goal was to measure the lowest detectable amounts of carbon atoms by 156.1 nm and 165.7 nm LIF. If equipment was functioning properly, it was expected that these goals would be met easily during the timeframe of the proposal, and that is the reason only modest funding was requested. The PI was only funded at half- time by Glenn during the summer months. All other work time was paid for by Whitworth College. The college also funded a student, Charles Shawley, who worked on the project during the spring.

  2. Ultrasonically synthesized organic liquid-filled chitosan microcapsules: part 2: characterization using AFM (atomic force microscopy) and combined AFM-confocal laser scanning fluorescence microscopy.

    Science.gov (United States)

    Mettu, Srinivas; Ye, Qianyu; Zhou, Meifang; Dagastine, Raymond; Ashokkumar, Muthupandian

    2018-04-25

    Atomic Force Microscopy (AFM) is used to measure the stiffness and Young's modulus of individual microcapsules that have a chitosan cross-linked shell encapsulating tetradecane. The oil filled microcapsules were prepared using a one pot synthesis via ultrasonic emulsification of tetradecane and crosslinking of the chitosan shell in aqueous solutions of acetic acid. The concentration of acetic acid in aqueous solutions of chitosan was varied from 0.2% to 25% v/v. The effect of acetic acid concentration and size of the individual microcapsules on the strength was probed. The deformations and forces required to rupture the microcapsules were also measured. Three dimensional deformations of microcapsules under large applied loads were obtained by the combination of Laser Scanning Confocal Microscopy (LSCM) with Atomic Force Microscopy (AFM). The stiffness, and hence the modulus, of the microcapsules was found to decrease with an increase in size with the average stiffness ranging from 82 to 111 mN m-1 and average Young's modulus ranging from 0.4 to 6.5 MPa. The forces required to rupture the microcapsules varied from 150 to 250 nN with deformations of the microcapsules up to 62 to 110% relative to their radius, respectively. Three dimensional images obtained using laser scanning confocal microscopy showed that the microcapsules retained their structure and shape after being subjected to large deformations and subsequent removal of the loads. Based on the above observations, the oil filled chitosan crosslinked microcapsules are an ideal choice for use in the food and pharmaceutical industries as they would be able to withstand the process conditions encountered.

  3. Simultaneous determination of total arsenic and total selenium in Chinese medicinal herbs by hydride generation atomic fluorescence spectrometry in tartaric acid medium

    International Nuclear Information System (INIS)

    Liu Zhanfeng; Sun Hanwen; Shen Shigang; Li Liqing; Shi Hongmei

    2005-01-01

    By HG-AFS, a new method was proposed for simultaneous determination of total arsenic and total selenium existed in the Chinese medicinal herbs in tartaric acid medium. The effects of analytical conditions and coexisting ions on the fluorescence signal intensity of analytes were investigated. The proposed method was provided with linear response ranges above 22 μg l -1 for As and 44 μg l -1 for Se, and the detection limits of 0.13 and 0.12 μg l -1 were obtained for As and Se respectively. The recoveries of 93.8-96.1% for As and 95.3-99.1% for Se, and the precision of 1.2-3.8% and 2.4-5.3% (R.S.D., n = 8) respectively, were obtained via simultaneous determined four samples of Chinese medicinal herbs and three certified botanic reference materials successfully. The proposed method has the advantages of simple operation, high sensitivity and high efficiency

  4. 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.

  5. 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...

  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 the foundati......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. A new vapor generation system for mercury species based on the UV irradiation of mercaptoethanol used in the determination of total and methyl mercury in environmental and biological samples by atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Yanmin; Qiu, Jianhua; Yang, Limin [College of Chemistry and Chemical Engineering, Xiamen University, Department of Chemistry and the MOE Key Laboratory of Analytical Sciences, Xiamen (China); Wang, Qiuquan [College of Chemistry and Chemical Engineering, Xiamen University, Department of Chemistry and the MOE Key Laboratory of Analytical Sciences, Xiamen (China); Xiamen University, State Key Laboratory of Marine Environmental Science, Xiamen (China)

    2007-06-15

    A new vapor generation system for mercury (Hg) species based on the irradiation of mercaptoethanol (ME) with UV was developed to provide an effective sample introduction unit for atomic fluorescence spectrometry (AFS). Preliminary investigations of the mechanism of this novel vapor generation system were based on GC-MS and FT-IR studies. Under optimum conditions, the limits of determination for inorganic divalence mercury and methyl mercury were 60 and 50 pg mL{sup -1}, respectively. Certified reference materials (BCR 463 tuna fish and BCR 580 estuarine sediment) were used to validate this new method, and the results agreed well with certified values. This new system provides an attractive alternative method of chemical vapor generation (CVG) of mercury species compared to other developed CVG systems (for example, the traditional KBH{sub 4}/NaOH-acid system). To our knowledge, this is the first systematic report on UV/ME-based Hg species vapor generation and the determination of total and methyl Hg in environmental and biological samples using UV/ME-AFS. (orig.)

  8. Analysis of trace and mineral elements in vanilla pods from the region of S.A.V.A using total reflection X-ray fluorescence, atomic absorption and ion chromatography techniques

    International Nuclear Information System (INIS)

    Be, K.

    2013-01-01

    In the case of studies of food security, - arsenic, cobalt, chromium, copper, iron, manganese, nickel, rubidium, selenium, strontium, titanium, zinc - cadmium, lead - are almost always analyzed. Guide values are used to express the level of quality in matter of consumption. Analytical laboratories of Madagascar-INSTN outline usually their research on quantifying those elements by using two different analytical methods, the Total Reflection X-Ray Fluorescence for the first twelve metals and the Atomic Absorption Spectrometry dedicated to lead and cadmium. Supplementary analysis is carried out for the quantification of essential mineral elements such as calcium, magnesium and potassium by using Ion Chromatograph. The aim of this study was to set up the analysis of the above mentioned elements in vanilla pods collected from Sambava, Antalaha and Andapa for a routine use. After all the parameters were established, the validation was particularly focused on the limits of detection and quantification and the accuracy of each element. The used methods fulfil the scope of application needed and are easy to use in routine. [fr

  9. Two-line hybrid rice male sterile line 'NHR111S' with a marker of green-revertible albino leaves

    International Nuclear Information System (INIS)

    Wu Wei; Liu Xin; Shu Xiaoli; Shu Qingyao; Xia Yingwu; Wu Dianxing

    2006-01-01

    NHR111S is a new two-line male sterile line with a marker of green-revertible albino leave that was bred from in vitro mutagens is of the thermo/photoperiod-sensitive male sterile line 'Guangzhan63S' by 60 Co γ-rays. It has the same desired agronomic traits, fertility characteristics and combining ability as characteristics of the parent. It is convenient to develop leaf color marker-aided elimination strategy in the multiplication and production of hybrid rice seeds. (authors)

  10. X-ray fluorescence holography.

    Science.gov (United States)

    Hayashi, Kouichi; Happo, Naohisa; Hosokawa, Shinya; Hu, Wen; Matsushita, Tomohiro

    2012-03-07

    X-ray fluorescence holography (XFH) is a method of atomic resolution holography which utilizes fluorescing atoms as a wave source or a monitor of the interference field within a crystal sample. It provides three-dimensional atomic images around a specified element and has a range of up to a few nm in real space. Because of this feature, XFH is expected to be used for medium-range local structural analysis, which cannot be performed by x-ray diffraction or x-ray absorption fine structure analysis. In this article, we explain the theory of XFH including solutions to the twin-image problem, an advanced measuring system, and data processing for the reconstruction of atomic images. Then, we briefly introduce our recent applications of this technique to the analysis of local lattice distortions in mixed crystals and nanometer-size clusters appearing in the low-temperature phase of a shape-memory alloy.

  11. X-ray fluorescence holography

    International Nuclear Information System (INIS)

    Hayashi, Kouichi; Happo, Naohisa; Hosokawa, Shinya; Hu Wen; Matsushita, Tomohiro

    2012-01-01

    X-ray fluorescence holography (XFH) is a method of atomic resolution holography which utilizes fluorescing atoms as a wave source or a monitor of the interference field within a crystal sample. It provides three-dimensional atomic images around a specified element and has a range of up to a few nm in real space. Because of this feature, XFH is expected to be used for medium-range local structural analysis, which cannot be performed by x-ray diffraction or x-ray absorption fine structure analysis. In this article, we explain the theory of XFH including solutions to the twin-image problem, an advanced measuring system, and data processing for the reconstruction of atomic images. Then, we briefly introduce our recent applications of this technique to the analysis of local lattice distortions in mixed crystals and nanometer-size clusters appearing in the low-temperature phase of a shape-memory alloy. (topical review)

  12. To test photon statistics by atomic beam deflection

    International Nuclear Information System (INIS)

    Wang Yuzhu; Chen Yudan; Huang Weigang; Liu Liang

    1985-02-01

    There exists a simple relation between the photon statistics in resonance fluorescence and the statistics of the momentum transferred to an atom by a plane travelling wave [Cook, R.J., Opt. Commun., 35, 347(1980)]. Using an atomic beam deflection by light pressure, we have observed sub-Poissonian statistics in resonance fluorescence of two-level atoms. (author)

  13. 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

    International Nuclear Information System (INIS)

    Huerga, A.; Lavilla, I.; Bendicho, C.

    2005-01-01

    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)

  14. Peptide-stabilized, fluorescent silver nanoclusters

    DEFF Research Database (Denmark)

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

    2016-01-01

    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...

  15. Selective breeding of two lines of guinea pigs differing in bronchial sensitivity to acetylcholine and histamine exposure.

    Science.gov (United States)

    Mikami, H; Nishibata, R; Kawamoto, Y; Ino, T

    1991-04-01

    We developed two lines of guinea pigs, one as model animals for bronchial asthma with bronchial hypersensitivity and the other with hyposensitivity as a control. In the last four years, the bronchial hypersensitive line (BHS) and hyposensitive line (BHR), both derived from Hartley strain guinea pigs, have been selected by using bronchial reactivity to acetylcholine and to histamine as parameters. Both lines have reached the F6 generation. The following results were obtained with the two lines: 1) Sib and cous in matings, and mating of selected consanguineous individuals were adopted in breeding BHS and BHR. The breeding started with six families, each, but in the F6 generation the number of families decreased to two in each line. 2) Appearance rates of hyper- or hyposensitivity to acetylcholine and histamine increased with successive generations in both lines, which had been completely separated by the F6 generation. 3) Coefficients of inbreeding in BHS and BHR in the F6 generation ranged from 42% to 45% in the former and 42% in the latter. 4) Heritabilities (h2) of BHS and BHR for the appearance rates of sensitivity to acetylcholine were presumed to be 0.54 in the former and 0.69 in the latter. 5) No difference in the body weight of 0, 20, and 40 day-old BHS was observed in any generation. On the other hand, the body weight of 20 and 40 day-old BHR tended to decrease with successive generations. 6) Mean litter sizes of BHS and BHR in each of the generations ranged from 2.24 to 3.47 animals in the former and from 2.63 to 3.38 animals in the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Atom optics

    International Nuclear Information System (INIS)

    Balykin, V. I.; Jhe, W.

    1999-01-01

    Atom optics, in analogy to neutron and electron optics, deals with the realization of as a traditional elements, such as lenes, mirrors, beam splitters and atom interferometers, as well as a new 'dissipative' elements such as a slower and a cooler, which have no analogy in an another types of optics. Atom optics made the development of atom interferometer with high sensitivity for measurement of acceleration and rotational possible. The practical interest in atom optics lies in the opportunities to create atom microprobe with atom-size resolution and minimum damage of investigated objects. (Cho, G. S.)

  17. Collisional and radiative processes in fluorescent lamps

    International Nuclear Information System (INIS)

    Lister, Graeme G.

    2003-01-01

    Since electrode life is the major limiting factor in operating fluorescent lamps, many lighting companies have introduced 'electrodeless' fluorescent lamps, using inductively coupled discharges. These lamps often operate at much higher power loadings than standard lamps and numerical models have not been successful in reproducing experimental measurements in the parameter ranges of interest. A comprehensive research program was undertaken to study the fundamental physical processes of these discharges, co-funded by the Electric Power Research Institute (EPRI) and OSRAM SYLVANIA under the name of ALITE. The program included experiments and modeling of radiation transport, computations of electron-atom and atom-atom cross sections and the first comprehensive power balance studies of a highly loaded fluorescent lamp. Results from the program and their importance to the understanding of the physics of fluorescent lamps are discussed, with particular emphasis on the important collisional and radiative processes. Comparisons between results of experimental measurements and numerical models are presented

  18. Dye lasers in atomic spectroscopy

    International Nuclear Information System (INIS)

    Lange, W.; Luther, J.; Steudel, A.

    1974-01-01

    The properties of dye lasers which are relevant to atomic spectroscopy are discussed. Several experiments made possible by tunable dye lasers are discussed. Applications of high spectral density dye lasers are covered in areas such as absorption spectroscopy, fluorescence spectroscopy, photoionization and photodetachment, and two- and multi-photon processes. Applications which take advantage of the narrow bandwidth of tunable dye lasers are discussed, including saturation spectroscopy, fluorescence line narrowing, classic absorption and fluorescence spectroscopy, nonoptical detection of optical resonances, heterodyne spectroscopy, and nonlinear coherent resonant phenomena. (26 figures, 180 references) (U.S.)

  19. Fluorescence microscopy.

    Science.gov (United States)

    Sanderson, Michael J; Smith, Ian; Parker, Ian; Bootman, Martin D

    2014-10-01

    Fluorescence microscopy is a major tool with which to monitor cell physiology. Although the concepts of fluorescence and its optical separation using filters remain similar, microscope design varies with the aim of increasing image contrast and spatial resolution. The basics of wide-field microscopy are outlined to emphasize the selection, advantages, and correct use of laser scanning confocal microscopy, two-photon microscopy, scanning disk confocal microscopy, total internal reflection, and super-resolution microscopy. In addition, the principles of how these microscopes form images are reviewed to appreciate their capabilities, limitations, and constraints for operation. © 2014 Cold Spring Harbor Laboratory Press.

  20. Atom-by-atom assembly

    International Nuclear Information System (INIS)

    Hla, Saw Wai

    2014-01-01

    Atomic manipulation using a scanning tunneling microscope (STM) tip enables the construction of quantum structures on an atom-by-atom basis, as well as the investigation of the electronic and dynamical properties of individual atoms on a one-atom-at-a-time basis. An STM is not only an instrument that is used to ‘see’ individual atoms by means of imaging, but is also a tool that is used to ‘touch’ and ‘take’ the atoms, or to ‘hear’ their movements. Therefore, the STM can be considered as the ‘eyes’, ‘hands’ and ‘ears’ of the scientists, connecting our macroscopic world to the exciting atomic world. In this article, various STM atom manipulation schemes and their example applications are described. The future directions of atomic level assembly on surfaces using scanning probe tips are also discussed. (review article)

  1. The application of atomic absorption spectrometry to chemical analysis

    International Nuclear Information System (INIS)

    Walsh, A.

    1980-01-01

    YhThe history of the development of atomic absorption methods of elemental analysis is outlined. The theoretical basis of atomic absorption methods is discussed and the principle of modern methods of atomic absorption measurements is described. The advantages, scope and limations of these methods are discussed. Related methods based on the measurement of atomic fluorescence are also described

  2. Photoionization of atoms and molecules

    International Nuclear Information System (INIS)

    Samson, J.A.R.

    1976-01-01

    A literature review on the present state of knowledge in photoionization is presented. Various experimental techniques that have been developed to study photoionization, such as fluorescence and photoelectron spectroscopy, mass spectroscopy, are examined. Various atoms and molecules were chosen to illustrate these techniques, specifically helium and xenon atoms and hydrogen molecules. Specialized photoionization such as in positive and negative ions, excited states, and free radicals is also treated. Absorption cross sections and ionization potentials are also discussed

  3. Lasers probe the atomic nucleus

    International Nuclear Information System (INIS)

    Eastham, D.

    1986-01-01

    The article is contained in a booklet on the Revised Nuffield Advanced Physics Course, and concentrates on two techniques to illustrate how lasers probe the atomic nucleus. Both techniques employ resonance fluorescence spectroscopy for obtaining atomic transition energies. The first uses lasers to determine the change in the nuclear charge radius with isotope, the second concerns the use of lasers for ultrasensitive detection of isotopes and elements. The application of lasers in resonance ionization spectroscopy and proton decay is also described. (UK)

  4. 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.

  5. Regulation of metabolism by dietary carbohydrates in two lines of rainbow trout divergently selected for muscle fat content.

    Science.gov (United States)

    Kamalam, Biju Sam; Medale, Françoise; Kaushik, Sadasivam; Polakof, Sergio; Skiba-Cassy, Sandrine; Panserat, Stephane

    2012-08-01

    Previous studies in two rainbow trout lines divergently selected for lean (L) or fat (F) muscle suggested that they differ in their ability to metabolise glucose. In this context, we investigated whether genetic selection for high muscle fat content led to a better capacity to metabolise dietary carbohydrates. Juvenile trout from the two lines were fed diets with or without gelatinised starch (17.1%) for 10 weeks, after which blood, liver, muscle and adipose tissues were sampled. Growth rate, feed efficiency and protein utilisation were lower in the F line than in the L line. In both lines, intake of carbohydrates was associated with a moderate post-prandial hyperglycaemia, a protein sparing effect, an enhancement of nutrient (TOR-S6) signalling cascade and a decrease of energy-sensing enzyme (AMPK). Gene expression of hepatic glycolytic enzymes was higher in the F line fed carbohydrates compared with the L line, but concurrently transcripts for the gluconeogenic enzymes was also higher in the F line, possibly impairing glucose homeostasis. However, the F line showed a higher gene expression of hepatic enzymes involved in lipogenesis and fatty acid bioconversion, in particular with an increased dietary carbohydrate intake. Enhanced lipogenic potential coupled with higher liver glycogen content in the F line suggests better glucose storage ability than the L line. Overall, the present study demonstrates the changes in hepatic intermediary metabolism resulting from genetic selection for high muscle fat content and dietary carbohydrate intake without, however, any interaction for an improved growth or glucose utilisation in the peripheral tissues.

  6. Lasers probe the atomic nucleus

    International Nuclear Information System (INIS)

    Eastham, D.

    1983-01-01

    The role of lasers in nuclear physics research is discussed including nuclear structure experiments involving the measurement of isotope shifts and hyperfine splitting in atomic energy levels in unstable nuclei by resonance fluorescence spectroscopy and the ultra sensitive detection of isotopic element abundances. (U.K.)

  7. Atomic polarizabilities

    International Nuclear Information System (INIS)

    Safronova, M. S.; Mitroy, J.; Clark, Charles W.; Kozlov, M. G.

    2015-01-01

    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

  8. 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.

  9. Atomic physics

    CERN Document Server

    Foot, Christopher J

    2007-01-01

    This text will thoroughly update the existing literature on atomic physics. Intended to accompany an advanced undergraduate course in atomic physics, the book will lead the students up to the latest advances and the applications to Bose-Einstein Condensation of atoms, matter-wave inter-ferometry and quantum computing with trapped ions. The elementary atomic physics covered in the early chapters should be accessible to undergraduates when they are first introduced to the subject. To complement. the usual quantum mechanical treatment of atomic structure the book strongly emphasizes the experimen

  10. Atomic physics

    International Nuclear Information System (INIS)

    Armbruster, P.; Beyer, H.; Bosch, F.; Dohmann, H.D.; Kozhuharov, C.; Liesen, D.; Mann, R.; Mokler, P.H.

    1984-01-01

    The heavy ion accelerator UNILAC is well suited to experiments in the field of atomic physics because, with the aid of high-energy heavy ions atoms can be produced in exotic states - that is, heavy atoms with only a few electrons. Also, in close collisions of heavy ions (atomic number Z 1 ) and heavy target atoms (Z 2 ) short-lived quasi-atomic 'superheavy' systems will be formed - huge 'atoms', where the inner electrons are bound in the field of the combined charge Z 1 + Z 2 , which exceeds by far the charge of the known elements (Z <= 109). Those exotic or transient superheavy atoms delivered from the heavy ion accelerator make it possible to study for the first time in a terrestrial laboratory exotic, but fundamental, processes, which occur only inside stars. Some of the basic research carried out with the UNILAC is discussed. This includes investigation of highly charged heavy atoms with the beam-foil method, the spectroscopy of highly charged slow-recoil ions, atomic collision studies with highly ionised, decelerated ions and investigations of super-heavy quasi-atoms. (U.K.)

  11. 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...

  12. Ubiquitous atom

    International Nuclear Information System (INIS)

    Spruch, G.M.; Spruch, L.

    1974-01-01

    The fundamentals of modern physics, including the basic physics and chemistry of the atom, elementary particles, cosmology, periodicity, and recent advances, are surveyed. The biology and chemistry of the life process is discussed to provide a background for considering the effects of atomic particles on living things. The uses of atomic power in space travel, merchant shipping, food preservation, desalination, and nuclear clocks are explored. (Pollut. Abstr.)

  13. Time resolved laser induced fluorescence on argon intermediate pressure microwave discharges : measuring the depopulation rates of the 4p and 5p excited levels as induced by electron and atom collisions

    NARCIS (Netherlands)

    Palomares Linares, J.M.; Graef, W.A.A.D.; Hubner, S.; Mullen, van der J.J.A.M.

    2013-01-01

    The reaction kinetics in the excitation space of Ar is explored by means of Laser Induced Fluorescence (LIF) experiments using the combination of high rep-rate YAG–Dye laser systems with a well defined and easily controllable surfatron induced plasma setup. The high rep-rate favors the photon

  14. Atomic physics

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Research activities in atomic physics at Lawrence Berkeley Laboratory during 1976 are described. Topics covered include: experiments on stored ions; test for parity violation in neutral weak currents; energy conservation and astrophysics; atomic absorption spectroscopy, atomic and molecular detectors; theoretical studies of quantum electrodynamics and high-z ions; atomic beam magnetic resonance; radiative decay from the 2 3 Po, 2 levels of helium-like argon; quenching of the metastable 2S/sub 1/2/ state of hydrogen-like argon in an external electric field; and lifetime of the 2 3 Po level of helium-like krypton

  15. Atomic physics

    CERN Document Server

    Born, Max

    1969-01-01

    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.

  16. Early Atomism

    Indian Academy of Sciences (India)

    https://www.ias.ac.in/article/fulltext/reso/015/10/0905-0925. Keywords. Atomic theory; Avogadro's hypothesis; atomic weights; periodic table; valence; molecular weights; molecular formula; isomerism. Author Affiliations. S Ramasesha1. Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, ...

  17. Atom spectroscopy

    International Nuclear Information System (INIS)

    Kodling, K.

    1981-01-01

    Experiments on atom photoabsorption spectroscopy using synchrotron radiation in the 10-1000 eV range are reviewed. Properties of the necessary synchrotron radiation and the experiment on absorption spectroscopy are briefly described. Comparison with other spectroscopy methods is conducted. Some data on measuring photoabsorption, photoelectron emission and atom mass spectra are presented [ru

  18. Exotic atoms

    International Nuclear Information System (INIS)

    Horvath, D.; Lambrecht, R.M.

    1984-01-01

    This bibliography on exotic atoms covers the years 1939 till 1982. The annual entries are headed by an introduction describing the state of affairs of the branch of science and listing the main applications in quantum electrodynamics, particle physics, nuclear physics, atomic physics, chemical physics and biological sciences. The bibliography includes an author index and a subject index. (Auth.)

  19. Experimental station for gas phase fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Stankiewicz, M.; Garcia, E. Melero; Ruiz, J. Alvarez; Erman, P.; Hatherly, P.A.; Kivimaeki, A.; Rachlew, E.; Rius i Riu, J.

    2004-01-01

    The details of an experimental setup for gas phase atomic and molecular fluorescence measurements using synchrotron radiation are described in this article. The most significant part of the apparatus is an optical arrangement, which allows for simultaneous measurements of dispersed as well as total fluorescence intensity using an effusive gas jet and an inbuilt gas cell assembled in a convenient plug and measure configuration. The first measurements concerning fluorescence of the N 2 molecule around the N 1s edge obtained with this setup are presented

  20. Laser stabilisation for velocity-selective atomic absorption

    NARCIS (Netherlands)

    Meijer, H.A.J.; Meulen, H.P. van der; Ditewig, F.; Wisman, C.J.; Morgenstern, R.

    1987-01-01

    A relatively simple method is described for stabilising a dye laser at a frequency ν = ν0 + νc in the vicinity of an atomic resonance frequency ν0. The Doppler effect is exploited by looking for atomic fluorescence when a laser beam is crossed with an atomic beam at certain angles αi. Absolute

  1. Atomic fusion, Gerrard atomic fusion

    International Nuclear Information System (INIS)

    Gerrard, T.H.

    1980-01-01

    In the approach to atomic fusion described here the heat produced in a fusion reaction, which is induced in a chamber by the interaction of laser beams and U.H.F. electromagnetic beams with atom streams, is transferred to a heat exchanger for electricity generation by a coolant flowing through a jacket surrounding the chamber. (U.K.)

  2. Superradiators created atom by atom

    Science.gov (United States)

    Meschede, Dieter

    2018-02-01

    High radiation rates are usually associated with macroscopic lasers. Laser radiation is “coherent”—its amplitude and phase are well-defined—but its generation requires energy inputs to overcome loss. Excited atoms spontaneously emit in a random and incoherent fashion, and for N such atoms, the emission rate simply increases as N. However, if these atoms are in close proximity and coherently coupled by a radiation field, this microscopic ensemble acts as a single emitter whose emission rate increases as N2 and becomes “superradiant,” to use Dicke's terminology (1). On page 662 of this issue, Kim et al. (2) show the buildup of coherent light fields through collective emission from atomic radiators injected one by one into a resonator field. There is only one atom ever in the cavity, but the emission is still collective and superradiant. These results suggest another route toward thresholdless lasing.

  3. Laser induced fluorescence spectroscopy for FTU

    International Nuclear Information System (INIS)

    Hughes, T.P.

    1995-07-01

    Laser induced fluorescence spectroscopy (LIFS) is based on the absorption of a short pulse of tuned laser light by a group of atoms and the observation of the resulting fluorescence radiation from the excited state. Because the excitation is resonant it is very efficient, and the fluorescence can be many times brighter than the normal spontaneous emission, so low number densities of the selected atoms can be detected and measured. Good spatial resolution can be achieved by using a narrow laser beam. If the laser is sufficiently monochromatic, and it can be tuned over the absorption line profile of the selected atoms, information can also be obtained about the velocities of the atoms from the Doppler effect which can broaden and shift the line. In this report two topics are examined in detail. The first is the effect of high laser irradiance, which can cause 'power broadening' of the apparent absorption line profile. The second is the effect of the high magnetic field in FTU. Detailed calculations are given for LIFS of neutral iron and molybdenum atoms, including the Zeeman effect, and the implementation of LIFS for these atoms on FTU is discussed

  4. Atomic interferometry

    International Nuclear Information System (INIS)

    Baudon, J.; Robert, J.

    2004-01-01

    Since the theoretical works of L. De Broglie (1924) and the famous experiment of Davisson and Germer (1927), we know that a wave is linked with any particle of mass m by the relation λ = h/(mv), where λ is the wavelength, v the particle velocity and h is the Planck constant. The basic principle of the interferometry of any material particle, atom, molecule or aggregate is simple: using a simple incident wave, several mutually consistent waves (with well-defined relative phases) are generated and controllable phase-shifts are introduced between them in order to generate a wave which is the sum of the previous waves. An interference figure is obtained which consists in a succession of dark and bright fringes. The atomic interferometry is based on the same principle but involves different techniques, different wave equations, but also different beams, sources and correlations which are described in this book. Because of the small possible wavelengths and the wide range of possible atomic interactions, atomic interferometers can be used in many domains from the sub-micron lithography to the construction of sensors like: inertial sensors, gravity-meters, accelerometers, gyro-meters etc. The first chapter is a preliminary study of the space and time diffraction of atoms. The next chapters is devoted to the description of slit, light separation and polarization interferometers, and the last chapter treats of the properties of Bose-Einstein condensates which are interesting in atomic interferometry. (J.S.)

  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 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.

  6. Atomic politics

    International Nuclear Information System (INIS)

    Skogmar, G.

    1979-01-01

    The authors basic point is that the military and civil sides of atomic energy cannot be separated. The general aim of the book is to analyze both the military and civil branches, and the interdependence between them, of American foreign policy in the atomic field. Atomic policy is seen as one of the most important imstruments of foreign policy which, in turn, is seen against the background of American imperialism in general. Firstly, the book investigates the most important means by which the United States has controlled the development in the nuclear field in other countries. These means include influencing the conditions of access to nuclear resources of various kinds, influencing the flow of technical-economic information and influencing international organizations and treaties bearing on atomic energy. The time period treated is 1945-1973. 1973 is chosen as the end-year of the study mainly because of the new conditions in the whole energy field initiated by the oil crisis in that year. The sources of the empirical work are mainly hearings before the Joint Committee on Atomic Energy of the U.S. Congress and legal material of various kinds. Secondly, the goals of the American policy are analyzed. The goals identified are armament effect, non-proliferation (horizontal), sales, and energy dependence. The relation between the main goals is discussed.The discussion is centered on the interdependence between the military and the civil aspects, conflict and coincidence of various goals, the relation between short-term and long-term goals, and the possibilities of using one goal as pretext for another. Thirdly, some causes of the changes in the atomic policy around 1953 and 1963 are identified. These are the strategic balance, the competitive situation, the capacity (of the American atomic productive apparatus), and the nuclear technological stage. The specific composition of these four factors at the two time-points can explain the changes of policy. (author)

  7. Interplay of vacuum-mediated inter- and intra-atomic couplings in a pair of atoms

    International Nuclear Information System (INIS)

    Schmid, Sandra Isabelle; Evers, Joerg

    2010-01-01

    The resonance fluorescence emitted by a system of two dipole-dipole interacting nearby four-level atoms in a J=1/2↔J=1/2 configuration is studied. This setup is the simplest realistic model system which provides a complete description of the (inter-atomic) dipole-dipole interaction for arbitrary orientation of the inter-atomic distance vector, and at the same time allows for intra-atomic spontaneously generated coherences. Our main interest is the interplay of both these different coupling mechanisms. We discuss different methods to analyze the contribution of the various vacuum-induced coupling constants to the total resonance fluorescence spectrum. These allow us to find a dressed state interpretation of the contribution of the different inter-atomic dipole-dipole couplings to the total spectrum. We further study the role of the spontaneously generated coherences, and identify two different contributions to the single-particle vacuum-induced couplings. We show that they have a noticeable impact on the total resonance fluorescence spectrum down to small inter-atomic distances, even though the dipole-dipole coupling constants then are much larger in magnitude than the the single-particle coupling constants. Interestingly, we find that the inter-atomic couplings can induce an effect of the intra-atomic spontaneously generated coherences on the observed spectra which is not present in single-atom systems.

  8. Atomic secrecy

    International Nuclear Information System (INIS)

    Sweet, W.

    1979-01-01

    An article, The H-Bomb Secret: How We Got It, Why We're Telling It, by Howard Morland was to be published in The Progressive magazine in February, 1979. The government, after learning of the author's and the editors' intention to publish the article and failing to persuade them to voluntarily delete about 20% of the text and all of the diagrams showing how an H-bomb works, requested a court injunction against publication. Acting under the Atomic Energy Act of 1954, US District Court Judge Robert W. Warren granted the government's request on March 26. Events dealing with the case are discussed in this publication. Section 1, Progressive Hydrogen Bomb Case, is discussed under the following: Court Order Blocking Magazine Report; Origins of the Howard Morland Article; Author's Motives, Defense of Publication; and Government Arguments Against Disclosure. Section 2, Access to Atomic Data Since 1939, contains information on need for secrecy during World War II; 1946 Atomic Energy Act and its effects; Soviet A-Bomb and the US H-Bomb; and consequences of 1954 Atomic Energy Act. Section 3, Disputed Need for Atomic Secrecy, contains papers entitled: Lack of Studies on H-Bomb Proliferation; Administration's Position on H-Bombs; and National Security Needs vs Free Press

  9. Antimatter atoms

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    In january 1996, CERN broadcasted the information of the creation of nine anti-hydrogen atoms, observed through disintegration products. The experimental facility was CERN LEAR ring. An antiproton beam scattered a xenon jet, and the resulting antimatter was first selected by its insensitivity to beam bending magnets. Their disintegration was detected in thin NaI detectors, in which the anti-atoms are at once deprived from their positron. Then, magnetic and time-of-flight spectrometers are used. (D.L.)

  10. 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

  11. Electron beam induced fluorescence measurements of the degree of hydrogen dissociation in hydrogen plasmas

    NARCIS (Netherlands)

    Smit, C.; Brussaard, G.J.H.; de Beer, E.C.M.; Schram, D.C.; Sanden, van de M.C.M.

    2004-01-01

    The degree of dissociation of hydrogen in a hydrogen plasma has been measured using electron beam induced fluorescence. A 20 kV, 1 mA electron beam excites both the ground state H atom and H2 molecule into atomic hydrogen in an excited state. From the resulting fluorescence the degree of

  12. X-ray Fluorescence Holography: Principles, Apparatus, and Applications

    Science.gov (United States)

    Hayashi, Kouichi; Korecki, Pawel

    2018-06-01

    X-ray fluorescence holography (XFH) is an atomic structure determination technique that combines the capabilities of X-ray diffraction and X-ray fluorescence spectroscopy. It provides a unique means of gaining fully three-dimensional information about the local atomic structure and lattice site positions of selected elements inside compound samples. In this work, we discuss experimental and theoretical aspects that are essential for the efficient recording and analysis of X-ray fluorescence holograms and review the most recent advances in XFH. We describe experiments performed with brilliant synchrotron radiation as well as with tabletop setups that employ conventional X-ray tubes.

  13. Continuous magnetic trapping of laser cooled atoms

    International Nuclear Information System (INIS)

    Bagnato, V.S.; Lafyatis, G.; Martin, A.G.; Raab, E.L.; Landry, J.; Ahmad-Bitar, R.N.; Pritchard, D.E.

    1987-01-01

    The authors present here initial results of the deceleration of a thermal atomic beam from -- 1000 to -- 100 m/s. The experiment was conducted in the 1.4-m long vertical superconducting solenoid which produced the slowing field. The fluorescence of the slowed atomic beam has been studied as a function of laser frequency. Figure 2 is a 12-GHz scan showing the fluorescence at a position 150 cm from the beginning of the solenoid. The wide peak corresponds to unslowed atoms with generally the initial velocity distribution. The second, narrower, peak corresponds to slowed atoms with a velocity of -- 150 m/s. Similar spectra have been obtained for various positions along the magnetic slower and trap. These data should allow better understanding of the cooling process and will be compared to computer models

  14. Atoms stories

    International Nuclear Information System (INIS)

    Radvanyi, P.; Bordry, M.

    1988-01-01

    Physicists from different countries told each evening during one learning week, to an audience of young people, some great discoveries in evoking the difficulties and problems to which the researchers were confronted. From Antiquity to a more recent history, it is a succession of atoms stories. (N.C.)

  15. Atomic physics

    International Nuclear Information System (INIS)

    Held, B.

    1991-01-01

    This general book describes the change from classical physics to quantum physics. The first part presents atom evolution since antiquity and introduces fundamental quantities and elements of relativity. Experiments which have contributed to the evolution of knowledge on matter are analyzed in the second part. Applications of wave mechanics to the study of matter properties are presented in the third part [fr

  16. 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

  17. 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.

  18. Reviews in fluorescence 2008

    CERN Document Server

    Geddes, Chris D

    2010-01-01

    This volume serves as a comprehensive collection of current trends and emerging hot topics in the field of fluorescence spectroscopy. It summarizes the year's progress in fluorescence and its applications as well as includes authoritative analytical reviews.

  19. Fluorescent optical position sensor

    Science.gov (United States)

    Weiss, Jonathan D.

    2005-11-15

    A fluorescent optical position sensor and method of operation. A small excitation source side-pumps a localized region of fluorescence at an unknown position along a fluorescent waveguide. As the fluorescent light travels down the waveguide, the intensity of fluorescent light decreases due to absorption. By measuring with one (or two) photodetectors the attenuated intensity of fluorescent light emitted from one (or both) ends of the waveguide, the position of the excitation source relative to the waveguide can be determined by comparing the measured light intensity to a calibrated response curve or mathematical model. Alternatively, excitation light can be pumped into an end of the waveguide, which generates an exponentially-decaying continuous source of fluorescent light along the length of the waveguide. The position of a photodetector oriented to view the side of the waveguide can be uniquely determined by measuring the intensity of the fluorescent light emitted radially at that location.

  20. Atom-surface potentials and atom interferometry

    International Nuclear Information System (INIS)

    Babb, J.F.

    1998-01-01

    Long-range atom-surface potentials characterize the physics of many actual systems and are now measurable spectroscopically in deflection of atomic beams in cavities or in reflection of atoms in atomic fountains. For a ground state, spherically symmetric atom the potential varies as -1/R 3 near the wall, where R is the atom-surface distance. For asymptotically large distances the potential is weaker and goes as -1/R 4 due to retardation arising from the finite speed of light. This diminished interaction can also be interpreted as a Casimir effect. The possibility of measuring atom-surface potentials using atomic interferometry is explored. The particular cases studied are the interactions of a ground-state alkali-metal atom and a dielectric or a conducting wall. Accurate descriptions of atom-surface potentials in theories of evanescent-wave atomic mirrors and evanescent wave-guided atoms are also discussed. (author)

  1. Safe biodegradable fluorescent particles

    Science.gov (United States)

    Martin, Sue I [Berkeley, CA; Fergenson, David P [Alamo, CA; Srivastava, Abneesh [Santa Clara, CA; Bogan, Michael J [Dublin, CA; Riot, Vincent J [Oakland, CA; Frank, Matthias [Oakland, CA

    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.

  2. Optimization of fluorescent proteins

    NARCIS (Netherlands)

    Bindels, D.S.; Goedhart, J.; Hink, M.A.; van Weeren, L.; Joosen, L.; Gadella (jr.), T.W.J.; Engelborghs, Y.; Visser, A.J.W.G.

    2014-01-01

    Nowadays, fluorescent protein (FP) variants have been engineered to fluoresce in all different colors; to display photoswitchable, or photochromic, behavior; or to show yet other beneficial properties that enable or enhance a still growing set of new fluorescence spectroscopy and microcopy

  3. Exotic atoms

    International Nuclear Information System (INIS)

    Kunselman, R.

    1993-01-01

    The experiments use a solid hydrogen layer to form muonic hydrogen isotopes that escape into vacuum. The method relies on transfer of the muon from protium to either a deuteron or a triton. The resulting muonic deuterium or muonic tritium will not immediately thermalize because of the very low elastic cross sections, and may be emitted from the surface of the layer. Measurements which detect decay electrons, muonic x-rays, and fusion products have been used to study the processes. A target has been constructed which exploits muonic atom emission in order to learn more about the energy dependence of transfer and muon molecular formation

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

    Directory of Open Access Journals (Sweden)

    Chuan-gen LU

    2010-09-01

    Full Text Available 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.

  5. 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.

  6. A scoring system to guide the decision for a new systemic treatment after at least two lines of palliative chemotherapy for metastatic cancers: a prospective study.

    Science.gov (United States)

    Chanez, Brice; Bertucci, François; Gilabert, Marine; Madroszyk, Anne; Rousseau, Frédérique; Perrot, Delphine; Viens, Patrice; Raoul, Jean-Luc

    2017-09-01

    A four-parameter score has been identified as associated with overall survival (OS) in patients with advanced cancer with an estimated survival inferior to 6 months. Here, we tested its prognostic value for OS in patients who had received more than two lines of systemic therapy. We prospectively enrolled patients with advanced cancer who were going to receive a third or more therapeutic line outside classical clinical guidelines. The four parameters (Eastern Cooperative Oncology Group performance status, number of metastatic sites, serum LDH, and serum albumin) were collected at baseline, allowing to calculate the score, which sorted the patients in three groups, A, B, and C (low, intermediate, and high score, respectively). We then searched for correlations between this grouping and clinicopathological features particularly OS. From August 2013 to March 2014, 65 patients were enrolled and corresponded after determining their score to 26 patients in group A, 30 in B, and 9 in C. The median OS of the cohort was 4.4 months, and the 6-month OS was 42%. Overall survival was different between the three groups, with respective 6-month OS equal to 80% in group A, 17% in group B, and 0% in group C and respective median OS of 9, 2.3, and 1.6 months. Such prognostic value persisted in multivariate analysis. Similar OS differences were observed in patients with PS ≤2. This simple scoring should help oncologists identify which patients, after at least two lines of systemic therapy, might benefit from best supportive care alone.

  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. 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.

  9. Theory of fluorescence in photonic crystals

    International Nuclear Information System (INIS)

    Vats, Nipun; John, Sajeev; Busch, Kurt

    2002-01-01

    We present a formalism for the description of fluorescence from optically active materials embedded in a photonic crystal structure possessing a photonic band gap or pseudogap. An electromagnetic field expansion in terms of Bloch modes of the crystal is used to develop the equations for fluorescence in terms of the local density of photon modes available to the emitting atoms in either the high or low dielectric regions of the crystal. We then obtain expressions for fluorescence spectra and emission dynamics for luminescent materials in photonic crystals. The validity of our formalism is demonstrated through the calculation of relevant quantities for model photon densities of states. The connection of our calculations to the description of realistic systems is discussed. We also describe the consequences of these analyses on the accurate description of the interaction between radiative systems and the electromagnetic reservoir within photonic crystals

  10. Morphing hydrogel patterns by thermo-reversible fluorescence switching.

    Science.gov (United States)

    Bat, Erhan; Lin, En-Wei; Saxer, Sina; Maynard, Heather D

    2014-07-01

    Stimuli responsive surfaces that show reversible fluorescence switching behavior in response to temperature changes were fabricated. Oligo(ethylene glycol) methacrylate thermoresponsive polymers with amine end-groups were prepared by atom transfer radical polymerization (ATRP). The polymers were patterned on silicon surfaces by electron beam (e-beam) lithography, followed by conjugation of self-quenching fluorophores. Fluorophore conjugated hydrogel thin films were bright when the gels were swollen; upon temperature-induced collapse of the gels, self-quenching of the fluorophores led to significant attenuation of fluorescence. Importantly, the fluorescence was regained when the temperature was cooled. The fluorescence switching behavior of the hydrogels for up to ten cycles was investigated and the swelling-collapse was verified by atomic force microscopy. Morphing surfaces that change shape several times upon increase in temperature were obtained by patterning multiple stimuli responsive polymers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Development of atomic spectroscopy technology

    International Nuclear Information System (INIS)

    Lee, Jong Min; Cha, Hyung Ki; Song, Kyu Seok; Yang, Ki Ho; Baik, Dae Hyun; Lee, Young Joo; Yi, Jong Hoon; Jeong, Do Young; Jeong, Eui Chang; Yoo, Byung Duk; Cha, Byung Heon; Kim, Seong Ho; Nam, Seong Mo; Kim, Sun Kuk; Lee, Byung Cheol; Choi, Hwa Lim; Ko, Dok Yung; Han, Jae Min; Rho, Si Pyo; Lim, Chang Hwan; Choi, An Seong

    1992-12-01

    This project is aimed for the 'Development of extraction and separation techniques for stable isotopes by atomic laser spectroscopy technique'. The project is devided by two sub-projects. One is the 'Development of the selective photoionization technology' and the other is 'Development of ultrasensitive spectroscopic analysis technololgy'. This year studies on Hg and Yb, both of which have 7 isotopes, have been performed and, as a result, it was proved that specific isotopes of these elements could be selectively extracted. In addition study on plasma extraction technique, development of atomizers, design of electron gun have been the result of the project in 1992. In second sub-project trace determination of Pb has been performed with laser resonance ionization spectroscopy. As a result 20 picogram of detection limit has been obtained. In addition to these results, design of high sensitive laser induced fluorescence detection system as well as remote sensing DIAL system have been done. (Author)

  12. Atomic reactor thermal engineering

    International Nuclear Information System (INIS)

    Kim, Gwang Ryong

    1983-02-01

    This book starts the introduction of atomic reactor thermal engineering including atomic reaction, chemical reaction, nuclear reaction neutron energy and soon. It explains heat transfer, heat production in the atomic reactor, heat transfer of fuel element in atomic reactor, heat transfer and flow of cooler, thermal design of atomic reactor, design of thermodynamics of atomic reactor and various. This deals with the basic knowledge of thermal engineering for atomic reactor.

  13. Atomic energy

    International Nuclear Information System (INIS)

    Ramanna, R.

    1978-01-01

    Development of nuclear science in India, particularly the research and development work at the Bhabha Atomic Research Centre (BARC), Bombay, is described. Among the wide range of materials developed for specific functions under rigorous conditions are nuclear pure grade uranium, zirconium and beryllium, and conventional materials like aluminium, carbon steel and stainless steels. Radioisotopes are produced and used for tracer studies in various fields. Various types of nuclear gauges and nuclear instruments are produced. Radiations have been used to develop new high yielding groundnut mutants with large kernals. The sterile male technique for pest control and radiosterilization technique to process potatoes, onions and marine foods for storage are ready for exploitation. Processes and equipment have been developed for production of electrolytic hydrogen, electrothermal phosphorus and desalinated water. Indigenously manufactured components and materials are now being used for the nuclear energy programme. Indian nuclear power programme strategy is to build heavy water reactors and to utilise their byproduct plutonium and depleted uranium to feed fast breeder reactors which will produce more fissile material than burnt. Finally a special mention has been made of the manpower development programme of the BARC. BARC has established a training school in 1957 giving advanced training in physics, chemistry and various branches of engineering and metallurgy

  14. Fluorescence of irradiated hydrocarbons

    International Nuclear Information System (INIS)

    Gulis, I.G.; Evdokimenko, V.M.; Lapkovskij, M.P.; Petrov, P.T.; Gulis, I.M.; Markevich, S.V.

    1977-01-01

    A visible fluorescence has been found out in γ-irradiated aqueous of carbohydrates. Two bands have been distinguished in fluorescence spectra of the irradiated solution of dextran: a short-wave band lambdasub(max)=140 nm (where lambda is a wave length) at lambdasub(β)=380 nm and a long-wave band with lambdasub(max)=540 nm at lambdasub(β)=430 nm. A similar form of the spectrum has been obtained for irradiated solutions of starch, amylopectin, lowmolecular glucose. It has been concluded that a macromolecule of polysaccharides includes fluorescent centres. A relation between fluorescence and α-oxiketon groups formed under irradiation has been pointed out

  15. Bremsstrahlung in atom-atom collisions

    International Nuclear Information System (INIS)

    Amus'ya, M.Y.; Kuchiev, M.Y.; Solov'ev, A.V.

    1985-01-01

    It is shown that in the collision of a fast atom with a target atom when the frequencies are on the order of the potentials or higher, there arises bremsstrahlung comparable in intensity with the bremsstrahlung emitted by an electron with the same velocity in the field of the target atom. The mechanism by which bremsstrahlung is produced in atom-atom collisions is elucidated. Results of specific calculations of the bremsstrahlung spectra are given for α particles and helium atoms colliding with xenon

  16. Impurity monitoring by laser-induced fluorescence techniques

    International Nuclear Information System (INIS)

    Gelbwachs, J.A.

    1984-01-01

    Laser-induced fluorescence spectroscopy can provide a highly sensitive and selective means of detecting atomic and ionic impurities. Because the photodetector can be physically isolated from the laser-excited region, these techniques can be applied to monitoring in hostile environments. The basic concepts behind fluorescence detection are reviewed. Saturated optical excitation is shown to maximize impurity atom emission yield while mitigating effects of laser intensity fluctuations upon absolute density calibration. Monitoring in high- and low-pressure monitoring environments is compared. Methods to improve detection sensitivity by luminescence background suppression are presented

  17. An X-ray fluorescence method for the determination of metals thicknesses

    International Nuclear Information System (INIS)

    Vazquez, Cristina; Leyt, D.V. de; Riveros, J.A.

    1987-01-01

    An absolute method for the determination of the thickness of a metal film deposited on a metallic substrate is described. The method is based on the measurement of fluorescent intensity ratios for two lines from the substrate element. Additionally, the proposed method can be employed to determine the density of the deposited material or the incident angle of primary radiation and take off angle, if the metal film thickness is known. (Author) [es

  18. Temperature measurement in a compressible flow field using laser-induced iodine fluorescence

    Science.gov (United States)

    Fletcher, D. G.; Mcdaniel, J. C.

    1987-01-01

    The thermometric capability of a two-line fluorescence technique using iodine seed molecules in air is investigated analytically and verified experimentally in a known steady compressible flow field. Temperatures ranging from 165 to 295 K were measured in the flowfield using two iodine transitions accessed with a 30-GHz dye-laser scan near 543 nm. The effect of pressure broadening on temperature measurement is evaluated.

  19. Membranes and Fluorescence microscopy

    DEFF Research Database (Denmark)

    Bagatolli, Luis

    2009-01-01

    Fluorescence spectroscopy-based techniques using conventional fluorimeters have been extensively applied since the late 1960s to study different aspects of membrane-related phenomena, i.e., mainly relating to lipid-lipid and lipid-protein (peptide) interactions. Even though fluorescence...

  20. Multimodal fluorescence imaging spectroscopy

    NARCIS (Netherlands)

    Stopel, Martijn H W; Blum, Christian; Subramaniam, Vinod; Engelborghs, Yves; Visser, Anthonie J.W.G.

    2014-01-01

    Multimodal fluorescence imaging is a versatile method that has a wide application range from biological studies to materials science. Typical observables in multimodal fluorescence imaging are intensity, lifetime, excitation, and emission spectra which are recorded at chosen locations at the sample.

  1. Analysis of a single-atom dipole trap

    International Nuclear Information System (INIS)

    Weber, Markus; Volz, Juergen; Saucke, Karen; Kurtsiefer, Christian; Weinfurter, Harald

    2006-01-01

    We describe a simple experimental technique which allows us to store a single 87 Rb atom in an optical dipole trap. Due to light-induced two-body collisions during the loading stage of the trap the maximum number of captured atoms is locked to one. This collisional blockade effect is confirmed by the observation of photon antibunching in the detected fluorescence light. The spectral properties of single photons emitted by the atom were studied with a narrow-band scanning cavity. We find that the atomic fluorescence spectrum is dominated by the spectral width of the exciting laser light field. In addition we observe a spectral broadening of the atomic fluorescence light due to the Doppler effect. This allows us to determine the mean kinetic energy of the trapped atom corresponding to a temperature of 105 μK. This simple single-atom trap is the key element for the generation of atom-photon entanglement required for future applications in quantum communication and a first loophole-free test of Bell's inequality

  2. Energetics and dynamics of atomic uranium levels

    International Nuclear Information System (INIS)

    Miron, E.

    1978-01-01

    New methods for discovering and identifying new electronic levels of atomic uranium and measuring parameters, such as radiative lifetimes and absorption cross-sections, are described. The uranium atoms are produced within an especially designed induction-heated oven. The uranium vapor is irradiated by nitrogen laser pumped, pulsed dye lasers. The various measurements are accomplished by detection of laser induced fluorescence from selectively excited levels. 138 atomic-uranium odd levels in the region 32260-34900 cm -1 and 16 even levels in the region 49500-49900 cm -1 are reported. Unique J values are presented for 64 levels and partial assignment (two possibilities) for 42 levels. Radiative lifetimes are presented for 134 levels. Absorption cross sections were measured for 12 transitions. Isotope shifts of 17 levels are given. Cross-sections for internal excitation transfer in uranium which are induced by collisions with argon atoms, are presented for 11 levels. (author)

  3. Thermally activated delayed fluorescence of fluorescein derivative for time-resolved and confocal fluorescence imaging.

    Science.gov (United States)

    Xiong, Xiaoqing; Song, Fengling; Wang, Jingyun; Zhang, Yukang; Xue, Yingying; Sun, Liangliang; Jiang, Na; Gao, Pan; Tian, Lu; Peng, Xiaojun

    2014-07-09

    Compared with fluorescence imaging utilizing fluorophores whose lifetimes are in the order of nanoseconds, time-resolved fluorescence microscopy has more advantages in monitoring target fluorescence. In this work, compound DCF-MPYM, which is based on a fluorescein derivative, showed long-lived luminescence (22.11 μs in deaerated ethanol) and was used in time-resolved fluorescence imaging in living cells. Both nanosecond time-resolved transient difference absorption spectra and time-correlated single-photon counting (TCSPC) were employed to explain the long lifetime of the compound, which is rare in pure organic fluorophores without rare earth metals and heavy atoms. A mechanism of thermally activated delayed fluorescence (TADF) that considers the long wavelength fluorescence, large Stokes shift, and long-lived triplet state of DCF-MPYM was proposed. The energy gap (ΔEST) of DCF-MPYM between the singlet and triplet state was determined to be 28.36 meV by the decay rate of DF as a function of temperature. The ΔE(ST) was small enough to allow efficient intersystem crossing (ISC) and reverse ISC, leading to efficient TADF at room temperature. The straightforward synthesis of DCF-MPYM and wide availability of its starting materials contribute to the excellent potential of the compound to replace luminescent lanthanide complexes in future time-resolved imaging technologies.

  4. Atomic weight versus atomic mass controversy

    International Nuclear Information System (INIS)

    Holden, N.E.

    1985-01-01

    A problem for the Atomic Weights Commission for the past decade has been the controversial battle over the names ''atomic weight'' and ''atomic mass''. The Commission has considered the arguments on both sides over the years and it appears that this meeting will see more of the same discussion taking place. In this paper, I review the situation and offer some alternatives

  5. A miniature magnetic waveguide for cold atoms

    International Nuclear Information System (INIS)

    Key, M.G.

    2000-09-01

    This thesis presents the first demonstration of a guide for cold atoms based on a miniature structure of four current-carrying wires. The four wires are embedded within a hollow silica fibre. Atoms are guided along the centre of a fifth hole on the axis of the fibre by the Stern-Gerlach force. A vapour cell Magneto Optical Trap (MOT), formed 1 cm above the mouth of the waveguide is the source of cold 85 Rb atoms. After cooling the atoms to 25 μK in optical molasses they fall under the influence of gravity through a magnetic funnel into the waveguide. After propagating for 2 cm, the atoms are reflected by the field of a small pinch coil wound around the base of the guide. The atoms then travel back up the fibre and out into the funnel, where they can be imaged either in fluorescence or by recapturing in the MOT. A video sequence of atoms falling into the guide and re-emerging after reflection from the pinch coil graphically illustrates the operation of the guide. The coupling efficiency and transverse temperature of the atoms is measured experimentally and in a Monte-Carlo simulation. We find an optimum coupling efficiency of 12% and we measure the spatial extent of the cloud within the fibre to be of order 100 μm. We find good agreement between experimental data and results from the numerical simulation. We have also been able to observe different thresholds for the reflection of different positive m F levels. In another experiment we are able to trap the atoms in an elongated Ioffe trap for up to two seconds, increasing the distance over which the atoms are guided. We are able to guide the atoms over distances of 40 cm with a loss rate indistinguishable from the free space loss rate. (author)

  6. Thermo-responsive and fluorescent cellulose nanocrystals grafted with polymer brushes

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Weibing [Nanjing Forestry Univ. (China); Georgia Inst. of Technology, Atlanta, GA (United States); Huang, Fang [Georgia Inst. of Technology, Atlanta, GA (United States); Pan, Shaobo [Georgia Inst. of Technology, Atlanta, GA (United States); Mu, Wei [Georgia Inst. of Technology, Atlanta, GA (United States); Meng, Xianzhi [Georgia Inst. of Technology, Atlanta, GA (United States); Yang, Haitao [Hubei Univ. of Technology, Wuhan (China); Xu, Zhaoyang [Nanjing Forestry Univ. (China); Ragauskas, Arthur J. [Georgia Inst. of Technology, Atlanta, GA (United States); Deng, Yulin [Georgia Inst. of Technology, Atlanta, GA (United States)

    2014-11-24

    Fluorescent and thermo-responsive cellulose nanocrystals (CNCs) with tuned polymer brushes were preparedviasurface initiated activators generated by electron transfer for atom transfer radical polymerization.

  7. Disparity in formulations used for fluorescent X-ray intensity measurements

    International Nuclear Information System (INIS)

    Mittal, Raj; Gupta, Sheenu

    2011-01-01

    The paper presents a problem in computations of X-ray fluorescence cross-sections, shell/sub-shell fluorescence yields, Coster-Kronig yields, vacancy alignment, etc. from X-ray fluorescence (XRF) studies. While using barn/atom as a unit for cross-sections if the atomic masses are not considered it causes a discrepancy in the measured cross-section, yield and alignment values. Most of the earlier publications are being quoted where such an oversight has occurred and discrepancy is evident. - Highlights: → Manuscript gives basic formulation for measurements of fluorescent X-ray intensities. → Most publications ignored the fact that use of barn/atom units for cross-sections requires atomic masses. → Published experimental results higher by a factor ≥2 or less by factor 1/M K . → Inspection of published data on XRF parameters needed.

  8. 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.

  9. 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.

  10. Highly excited atoms

    International Nuclear Information System (INIS)

    Kleppner, D.; Littman, M.G.; Zimmerman, M.L.

    1981-01-01

    Highly excited atoms are often called Rydberg atoms. These atoms have a wealth of exotic properties which are discussed. Of special interest, are the effects of electric and magnetic fields on Rydberg atoms. Ordinary atoms are scarcely affected by an applied electric or magnetic field; Rydberg atoms can be strongly distorted and even pulled apart by a relatively weak electric field, and they can be squeezed into unexpected shapes by a magnetic field. Studies of the structure of Rydberg atoms in electric and magnetic fields have revealed dramatic atomic phenomena that had not been observed before

  11. Atomic physics research with synchrotron radiation

    International Nuclear Information System (INIS)

    Crasemann, B.; Wuilleumier, F.

    1985-01-01

    This chapter discusses applications of synchrotron light in atomic and molecular physics. Use of the radiation from storage rings has expanded and lent access to new areas of absorption and photoemission spectroscopy and scattering experiments. Techniques applied in connection with synchrotron radiation are discussed including absorption spectroscopy, photoelectron spectroscopy, fluorescence spectroscopy and X-ray scattering. Problem areas that are being studied by the techniques mentioned above are discussed. Synchrotron radiation has provided the means for measuring the threshold-excitation and interference effects that signal the breakdown of the two-step model of atomic excitation/deexcitation. Synchrotron radiation provides more means of excited-state photoionization measurements

  12. Laser-assisted atom-atom collisions

    International Nuclear Information System (INIS)

    Roussel, F.

    1984-01-01

    The basic layer-assisted atom-atom collision processes are reviewed in order to get a simpler picture of the main physical facts. The processes can be separated into two groups: optical collisions where only one atom is changing state during the collision, the other acting as a spectator atom, and radiative collisions where the states of the two atoms are changing during the collision. All the processes can be interpreted in terms of photoexcitation of the quasimolecule formed during the collisional process. (author)

  13. Code ATOM for calculation of atomic characteristics

    International Nuclear Information System (INIS)

    Vainshtein, L.A.

    1990-01-01

    In applying atomic physics to problems of plasma diagnostics, it is necessary to determine some atomic characteristics, including energies and transition probabilities, for very many atoms and ions. Development of general codes for calculation of many types of atomic characteristics has been based on general but comparatively simple approximate methods. The program ATOM represents an attempt at effective use of such a general code. This report gives a brief description of the methods used, and the possibilities of and limitations to the code are discussed. Characteristics of the following processes can be calculated by ATOM: radiative transitions between discrete levels, radiative ionization and recombination, collisional excitation and ionization by electron impact, collisional excitation and ionization by point heavy particle (Born approximation only), dielectronic recombination, and autoionization. ATOM explores Born (for z=1) or Coulomb-Born (for z>1) approximations. In both cases exchange and normalization can be included. (N.K.)

  14. 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.

  15. Fluorescent discharge lamp

    Science.gov (United States)

    Mukai, E.; Otsuka, H.; Nomi, K.; Honmo, I.

    1982-01-01

    A rapidly illuminating fluorescent lamp 1,200 mm long and 32.5 mm in diameter with an interior conducting strip which is compatible with conventional fixtures and ballasts is described. The fluorescent lamp is composed of a linear glass tube, electrodes sealed at both ends, mercury and raregas sealed in the glass tube, a fluorescent substance clad on the inner walls of the glass tube, and a clad conducting strip extending the entire length of the glass tube in the axial direction on the inner surface of the tube.

  16. 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

    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.

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

    International Nuclear Information System (INIS)

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

    2017-01-01

    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.

  18. Mercury mass measurement in fluorescent lamps via neutron activation analysis

    Czech Academy of Sciences Publication Activity Database

    Viererbl, L.; Vinš, M.; Lahodová, Z.; Fuksa, A.; Kučera, Jan; Koleska, M.; Voljanskij, A.

    2015-01-01

    Roč. 116, NOV (2015), s. 56-59 ISSN 0969-806X R&D Projects: GA TA ČR TA01010237; GA MŠk LM2011019 Institutional support: RVO:61389005 Keywords : fluorescent lamp * mercury measurement * neutron activation analysis * research reactor Subject RIV: BG - Nuclear , Atomic and Molecular Physics, Colliders Impact factor: 1.207, year: 2015

  19. Limestone rocks analysis by X-ray fluorescence analysis

    International Nuclear Information System (INIS)

    Izquierdo M, G.; Ponce R, R.; Vazquez J, J.

    1996-01-01

    By request of a private company, employing basically X-ray fluorescence analysis (X RF), was established a fast and accurate method for the analysis of the major elements in limestone rocks. Additionally, for complementing analysis was determined by ion chromatography, the chlorides appearance and by atomic absorption of sodium. By gravimetry, was determined the losses by ignition and the alpha quartz. (Author)

  20. Reviews in fluorescence 2007

    CERN Document Server

    Lakowicz, Joseph R; Geddes, Chris D

    2009-01-01

    This fourth volume in the Springer series summarizes the year's progress in fluorescence, with authoritative analytical reviews specialized enough for professional researchers, yet also appealing to a wider audience of scientists in related fields.

  1. 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...

  2. Fluorescence (Multiwave) Confocal Microscopy.

    Science.gov (United States)

    Welzel, J; Kästle, Raphaela; Sattler, Elke C

    2016-10-01

    In addition to reflectance confocal microscopy, multiwave confocal microscopes with different laser wavelengths in combination with exogenous fluorophores allow fluorescence mode confocal microscopy in vivo and ex vivo. Fluorescence mode confocal microscopy improves the contrast between the epithelium and the surrounding soft tissue and allows the depiction of certain structures, like epithelial tumors, nerves, and glands. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Atomic fountain and applications

    International Nuclear Information System (INIS)

    Rawat, H.S.

    2000-01-01

    An overview of the development of working of MOT along with the basic principle of laser atom cooling and trapping is given. A technique to separate the cooled and trapped atoms from the MOT using atomic fountain technique will also be covered. The widely used technique for atomic fountain is, first to cool and trap the neutral atoms in MOT and then launch them in the vertical direction, using moving molasses technique. Using 133 Cs atomic fountain clock, time improvement of 2 to 3 order of magnitude over a conventional 133 Cs atomic clock has been observed

  4. Interferometry with atoms

    International Nuclear Information System (INIS)

    Helmcke, J.; Riehle, F.; Witte, A.; Kisters, T.

    1992-01-01

    Physics and experimental results of atom interferometry are reviewed and several realizations of atom interferometers are summarized. As a typical example of an atom interferometer utilizing the internal degrees of freedom of the atom, we discuss the separated field excitation of a calcium atomic beam using four traveling laser fields and demonstrate the Sagnac effect in a rotating interferometer. The sensitivity of this interferometer can be largely increased by use of slow atoms with narrow velocity distribution. We therefore furthermore report on the preparation of a laser cooled and deflected calcium atomic beam. (orig.)

  5. Fluorescent magnetic hybrid nanoprobe for multimodal bioimaging

    Energy Technology Data Exchange (ETDEWEB)

    Koktysh, Dmitry [Department of Chemistry, Vanderbilt University, Station B 351822, Nashville, TN 37235 (United States); Bright, Vanessa; Pham, Wellington, E-mail: dmitry.koktysh@vanderbilt.edu, E-mail: wellington.pham@vanderbilt.edu [Institute of Imaging Science, Vanderbilt University, 1161 21st Avenue South AA, 1105 MCN, Nashville, TN 37232 (United States)

    2011-07-08

    A fluorescent magnetic hybrid imaging nanoprobe (HINP) was fabricated by the conjugation of superparamagnetic Fe{sub 3}O{sub 4} nanoparticles and visible light emitting ({approx}600 nm) fluorescent CdTe/CdS quantum dots (QDs). The assembly strategy used the covalent linking of the oxidized dextran shell of magnetic particles to the glutathione ligands of QDs. The synthesized HINP formed stable water-soluble colloidal dispersions. The structure and properties of the particles were characterized by transmission electron and atomic force microscopy, energy dispersive x-ray analysis and inductively coupled plasma optical emission spectroscopy, dynamic light scattering analysis, optical absorption and photoluminescence spectroscopy, and fluorescent imaging. The luminescence imaging region of the nanoprobe was extended to the near-infrared (NIR) ({approx}800 nm) by conjugation of the superparamagnetic nanoparticles with synthesized CdHgTe/CdS QDs. Cadmium, mercury based QDs in HINP can be easily replaced by novel water-soluble glutathione stabilized AgInS{sub 2}/ZnS QDs to present a new class of cadmium-free multimodal imaging agents. The observed NIR photoluminescence of fluorescent magnetic nanocomposites supports their use for bioimaging. The developed HINP provides dual-imaging channels for simultaneous optical and magnetic resonance imaging.

  6. Calcium Atom Trap for Atom Trap Mass Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Kwang Hoon; Park, Hyun Min; Han, Jae Min; Kim, Taek Soo; Cha, Yong Ho; Lim, Gwon; Jeong, Do Young [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    Trace isotope analysis has been an important role in science, archaeological dating, geology, biology and nuclear industry. Artificially produced fission products such as Sr-90, Cs-135 and Kr-85 can be released to the environment when nuclear accident occurs and the reprocessing factory operates. Thus, the analysis of them has been of interest in nuclear industry. But it is difficult to detect them due to low natural abundance less then 10-10. The ultra-trace radio isotopes have been analyzed by the radio-chemical method, accelerator mass spectrometer, and laser based method. The radiochemical method has been used in the nuclear industry. But this method has disadvantages of long measurement time for long lived radioisotopes and toxic chemical process for the purification. The accelerator mass spectrometer has high isotope selectivity, but the system is huge and it has the isobar effects. The laser based method, such as RIMS (Resonance Ionization Mass Spectrometry) is a basically isobar-effect free method. Recently, ATTA (Atom Trap Trace Analysis), one of the laser based method, has been successfully demonstrated sufficient isotope selectivity with small system size. It has been applied for the detection of Kr-81 and Kr-85. However, it is not suitable for real sample detection, because it requires steady atomic beam generation during detection and is not allowed simultaneous detection of other isotopes. Therefore, we proposed the coupled method of Atom Trap and Mass Spectrometer. It consists of three parts, neutral atom trap, ionization and mass spectrometer. In this paper, we present the demonstration of the magneto-optical trap of neutral calcium. We discuss the isotope selective characteristics of the MOT (Magneto Optical Trap) of calcium by the fluorescence measurement. In addition, the frequency stabilization of the trap beam will be presented

  7. Three-atom clusters

    International Nuclear Information System (INIS)

    Pen'kov, F.M.

    1998-01-01

    The Born-Oppenheimer approximation is used to obtain an equation for the effective interaction in three atoms bound by a single electron. For low binding energies in an 'electron + atom' pair, long-range forces arise between the atoms, leading to bound states when the size of the three-atom cluster is a few tens of angstrom. A system made of alkali-metal atoms is considered as an example

  8. Stable atomic hydrogen: Polarized atomic beam source

    International Nuclear Information System (INIS)

    Niinikoski, T.O.; Penttilae, S.; Rieubland, J.M.; Rijllart, A.

    1984-01-01

    We have carried out experiments with stable atomic hydrogen with a view to possible applications in polarized targets or polarized atomic beam sources. Recent results from the stabilization apparatus are described. The first stable atomic hydrogen beam source based on the microwave extraction method (which is being tested ) is presented. The effect of the stabilized hydrogen gas density on the properties of the source is discussed. (orig.)

  9. Fluorescence Image Segmentation by using Digitally Reconstructed Fluorescence Images

    OpenAIRE

    Blumer, Clemens; Vivien, Cyprien; Oertner, Thomas G; Vetter, Thomas

    2011-01-01

    In biological experiments fluorescence imaging is used to image living and stimulated neurons. But the analysis of fluorescence images is a difficult task. It is not possible to conclude the shape of an object from fluorescence images alone. Therefore, it is not feasible to get good manual segmented nor ground truth data from fluorescence images. Supervised learning approaches are not possible without training data. To overcome this issues we propose to synthesize fluorescence images and call...

  10. Fluorescence and Four-Wave Mixing in Electromagnetically Induced Transparency Windows

    International Nuclear Information System (INIS)

    Wang Zhi-Guo; Li Cheng; Zhang Zhao-Yang; Che Jun-Ling; Qin Meng-Zhe; He Jia-Nan; Zhang Yan-Peng

    2013-01-01

    We simultaneously compare the probe transmission, Four-Wave Mixing (FWM) and fluorescence signals with dressing effects in a four-level atomic system. The variation rules of three types of signals are exhibited by changing the frequency detuning and power of incident laser beams. The interplay between two ladder subsystems is investigated in the Y-type atomic system. In particular, the fluorescence signal with ultra-narrow linewidth is obtained due to being sheared twice by the electromagnetically induced transparency window. Such fluorescence with very high coherence and monochromaticity can be used for the quantum correlation and narrow linewidth laser

  11. 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...

  12. 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...

  13. Microfabricated Waveguide Atom Traps.

    Energy Technology Data Exchange (ETDEWEB)

    Jau, Yuan-Yu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    A nanoscale , microfabricated waveguide structure can in - principle be used to trap atoms in well - defined locations and enable strong photon-atom interactions . A neutral - atom platform based on this microfabrication technology will be prealigned , 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.

  14. Progress in atomic spectroscopy

    International Nuclear Information System (INIS)

    Beyer, H.J.; Kleinpoppen, H.

    1984-01-01

    This book presents reviews by leading experts in the field covering areas of research at the forefront of atomic spectroscopy. Topics considered include the k ordering of atomic structure, multiconfiguration Hartree-Fock calculations for complex atoms, new methods in high-resolution laser spectroscopy, resonance ionization spectroscopy (inert atom detection), trapped ion spectroscopy, high-magnetic-field atomic physics, the effects of magnetic and electric fields on highly excited atoms, x rays from superheavy collision systems, recoil ion spectroscopy with heavy ions, investigations of superheavy quasi-atoms via spectroscopy of electron rays and positrons, impact ionization by fast projectiles, and amplitudes and state parameters from ion- and atom-atom excitation processes

  15. Atomic Fisher information versus atomic number

    International Nuclear Information System (INIS)

    Nagy, A.; Sen, K.D.

    2006-01-01

    It is shown that the Thomas-Fermi Fisher information is negative. A slightly more sophisticated model proposed by Gaspar provides a qualitatively correct expression for the Fisher information: Gaspar's Fisher information is proportional to the two-third power of the atomic number. Accurate numerical calculations show an almost linear dependence on the atomic number

  16. 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

  17. 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

  18. Continuous imaging of a single neutral atom in a variant magneto-optical trap

    International Nuclear Information System (INIS)

    Xia Tian; Zhou Shuyu; Chen Peng; Li Lin; Hong Tao; Wang Yuzhu

    2010-01-01

    We demonstrate continuous imaging of a single 87 Rb atom confined in a steep magneto-optical trap with an electron-multiplying charge-coupled device (EMCCD) camera and realize a one-dimensional micro-optical trap array with a Dammann grating. We adopt several methods to reduce the noise in the fluorescence signal we obtain with the EMCCD. Step jumping characteristics of the fluorescence demonstrate capturing and losing of individual atoms. (authors)

  19. Advanced in X-ray fluorescence holography

    CERN Document Server

    Hayashi, K

    2002-01-01

    X-ray fluorescence holography (XFH) can resolve 'phase problem' in crystal diffraction and therefore it provides 3D atomic images around specific elements. Since first demonstration of the XFH in 1996, view of atoms has been improved rapidly with the refinement of the hologram data collection method. The present performance of the XFH makes it possible to apply to impurity, thin film and quasicrystal, and opens a way to practical tool for determination of local structure. In this paper, theory including solutions for twin image problem, advanced experimental systems and application to Si sub 0 sub . sub 9 sub 9 sub 9 Ge sub 0 sub . sub 0 sub 0 sub 1 are discussed. (author)

  20. Nanosecond fluorescence spectroscopy

    International Nuclear Information System (INIS)

    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. Fluorescence uranium determination

    International Nuclear Information System (INIS)

    Fernandez Cellini, R.; Crus Castillo, F. de la; Barrera Pinero, R.

    1960-01-01

    An equipment for analysis of uranium by fluorescence was developed in order to determine it at such a low concentration that it can not be determined by the most sensible analytical methods. this new fluorimeter was adapted to measure the fluorescence emitted by the phosphorus sodium fluoride-sodium carbonate-potasium carbonate-uranyl, being excited by ultraviolet light of 3,650 A the intensity of the light emitted was measure with a photomultiplicator RCA 5819 and the adequate electronic equipment. (Author) 19 refs

  2. A Single Atom Antenna

    International Nuclear Information System (INIS)

    Trinter, Florian; Williams, Joshua B; Weller, Miriam; Waitz, Markus; Pitzer, Martin; Voigtsberger, Jörg; Schober, Carl; Kastirke, Gregor; Müller, Christian; Goihl, Christoph; Burzynski, Phillip; Wiegandt, Florian; Wallauer, Robert; Kalinin, Anton; Schmidt, Lothar Ph H; Schöffler, Markus S; Jahnke, Till; Dörner, Reinhard; Chiang, Ying-Chih; Gokhberg, Kirill

    2015-01-01

    Here we demonstrate the smallest possible implementation of an antenna-receiver complex which consists of a single (helium) atom acting as the antenna and a second (neon) atom acting as a receiver. (paper)

  3. Atom chips: mesoscopic physics with cold atoms

    International Nuclear Information System (INIS)

    Krueger, P.; Wildermuth, S.; Hofferberth, S.; Haller, E.; GAllego Garcia, D.; Schmiedmayer, J.

    2005-01-01

    Full text: Cold neutral atoms can be controlled and manipulated in microscopic potentials near surfaces of atom chips. These integrated micro-devices combine the known techniques of atom optics with the capabilities of well established micro- and nanofabrication technology. In analogy to electronic microchips and integrated fiber optics, the concept of atom chips is suitable to explore the domain of mesoscopic physics with matter waves. We use current and charge carrying structures to form complex potentials with high spatial resolution only microns from the surface. In particular, atoms can be confined to an essentially one-dimensional motion. In this talk, we will give an overview of our experiments studying the manipulation of both thermal atoms and BECs on atom chips. First experiments in the quasi one-dimensional regime will be presented. These experiments profit from strongly reduced residual disorder potentials caused by imperfections of the chip fabrication with respect to previously published experiments. This is due to our purely lithographic fabrication technique that proves to be advantageous over electroplating. We have used one dimensionally confined BECs as an ultra-sensitive probe to characterize these potentials. These smooth potentials allow us to explore various aspects of the physics of degenerate quantum gases in low dimensions. (author)

  4. Quasi-atoms

    International Nuclear Information System (INIS)

    Armbruster, P.

    1976-01-01

    The concept of a quasi-atom is discussed, and several experiments are described in which molecular or quasi-atomic transitions have been observed. X-ray spectra are shown for these experiments in which heavy ion projectiles were incident on various targets and the resultant combined system behaved as a quasi-atom. This rapidly developing field has already given new insight into atomic collision phenomena. (P.J.S.)

  5. Atomic Energy Control Act

    International Nuclear Information System (INIS)

    1970-01-01

    This act provides for the establishment of the Atomic Energy Control Board. The board is responsible for the control and supervision of the development, application and use of atomic energy. The board is also considered necessary to enable Canada to participate effectively in measures of international control of atomic energy

  6. 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.

  7. Molecular engineering and fluorescence for the detection of toxic cations

    International Nuclear Information System (INIS)

    Souchon, V.

    2007-11-01

    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 2+ , Cd 2+ and Cs + 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 β-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)

  8. Monitoring by fluorescence measurements

    International Nuclear Information System (INIS)

    Malcolme-Lawes, D.J.; Gifford, L.A.

    1981-01-01

    A fluorimetric detector is described in which the fluorescence excitation source may be 3 H, 14 C, 35 S, 147 Pm or 63 Ni. Such a detector can be adapted for use with flowing liquid systems especially liquid chromatography systems. (U.K.)

  9. Fluorescence lifetime based bioassays

    Science.gov (United States)

    Meyer-Almes, Franz-Josef

    2017-12-01

    Fluorescence lifetime (FLT) is a robust intrinsic property and material constant of fluorescent matter. Measuring this important physical indicator has evolved from a laboratory curiosity to a powerful and established technique for a variety of applications in drug discovery, medical diagnostics and basic biological research. This distinct trend was mainly driven by improved and meanwhile affordable laser and detection instrumentation on the one hand, and the development of suitable FLT probes and biological assays on the other. In this process two essential working approaches emerged. The first one is primarily focused on high throughput applications employing biochemical in vitro assays with no requirement for high spatial resolution. The second even more dynamic trend is the significant expansion of assay methods combining highly time and spatially resolved fluorescence data by fluorescence lifetime imaging. The latter approach is currently pursued to enable not only the investigation of immortal tumor cell lines, but also specific tissues or even organs in living animals. This review tries to give an actual overview about the current status of FLT based bioassays and the wide range of application opportunities in biomedical and life science areas. In addition, future trends of FLT technologies will be discussed.

  10. Fluorescent Lamp Replacement Study

    Science.gov (United States)

    2017-07-01

    not be cited for purposes of advertisement. DISPOSITION INSTRUCTIONS: Destroy this document when no longer needed. Do not return to the... recycling , and can be disposed safely in a landfill. (2) LEDs offer reduced maintenance costs and fewer bulb replacements, significantly reducing... recycling . Several fixtures, ballasts and energy efficient fluorescent bulbs that were determined to be in pristine condition were returned to ATC

  11. Chromosome structure investigated with the atomic force microscope

    NARCIS (Netherlands)

    de Grooth, B.G.; Putman, C.A.J.; Putman, Constant A.; van der Werf, Kees; van Hulst, N.F.; van Oort, G.; van Oort, Geeske; Greve, Jan; Manne, Srinivas

    1992-01-01

    We have developed an atomic force microscope (AFM) with an integrated optical microscope. The optical microscope consists of an inverted epi-illumination system that yields images in reflection or fluorescence of the sample. With this system it is possible to quickly locate an object of interest. A

  12. Nuclear and atomic spectroscopy group. Dosimetry in medical physics

    International Nuclear Information System (INIS)

    Rubio, M.

    1990-01-01

    The main activities of radiation physics on the sector of atomic spectroscopy and x-ray fluorescence analysis in the Faculty of Mathematics, Astronomy and Physics (University of Cordoba, Argentina),are presented, including dosimetric studies in radiodiagnostic: dosimetric determination using Monte Carlo method; distortion effect study on PET image and lasers in medicine. (C.G.C.)

  13. Bringing atomic and nuclear physics laboratory data into the classroom

    International Nuclear Information System (INIS)

    Norman, Eric B.; Larimer, Ruth-Mary; Rech, Gregory; Lee, Jeffrey; Vue, Chue; Leubane, Tholoana; Zamvil, Kenneth; Guthrie, Laura

    2003-01-01

    To illustrate a number of basic concepts in atomic and nuclear physics, we have developed three websites where students can analyze data from modern laboratories. By working through the on-line procedures, students will become acquainted with characteristic x-ray spectra, the concept of half-life, x-ray fluorescence, and neutron activation analysis

  14. Atom-atom collision cascades localization

    International Nuclear Information System (INIS)

    Kirsanov, V.V.

    1980-01-01

    The presence of an impurity and thermal vibration influence on the atom-atom collision cascade development is analysed by the computer simulation method (the modificated dynamic model). It is discovered that the relatively low energetic cascades are localized with the temperature increase of an irradiated crystal. On the basis of the given effect the mechanism of splitting of the high energetic cascades into subcascades is proposed. It accounts for two factors: the primary knocked atom energy and the irradiated crystal temperature. Introduction of an impurity also localizes the cascades independently from the impurity atom mass. The cascades localization leads to intensification of the process of annealing in the cascades and reduction of the post-cascade vacancy cluster sizes. (author)

  15. 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

  16. Parallel Low-Loss Measurement of Multiple Atomic Qubits.

    Science.gov (United States)

    Kwon, Minho; Ebert, Matthew F; Walker, Thad G; Saffman, M

    2017-11-03

    We demonstrate low-loss measurement of the hyperfine ground state of rubidium atoms by state dependent fluorescence detection in a dipole trap array of five sites. The presence of atoms and their internal states are minimally altered by utilizing circularly polarized probe light and a strictly controlled quantization axis. We achieve mean state detection fidelity of 97% without correcting for imperfect state preparation or background losses, and 98.7% when corrected. After state detection and correction for background losses, the probability of atom loss due to the state measurement is state is preserved with >98% probability.

  17. Statistical filtering in fluorescence microscopy and fluorescence correlation spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Macháň, Radek; Kapusta, Peter; Hof, Martin

    Roč. 406 , č. 20 (2014), s. 4797-4813 ISSN 1618-2642 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388955 Keywords : Filtered fluorescence correlation spectroscopy * Fluorescence lifetime correlation spectroscopy * Fluorescence spectral correlation spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.436, year: 2014

  18. Atomic physics at high brilliance synchrotron sources: Proceedings

    International Nuclear Information System (INIS)

    Berry, G.; Cowan, P.; Gemmell, D.

    1994-08-01

    This report contains papers on the following topics: present status of SPring-8 and the atomic physics undulator beamline; recent photoabsorption measurements in the rare gases and alkalis in the 3 to 15 keV proton energy region; atomic and molecular physics at LURE; experiments on atoms, ions and small molecules using the new generation of synchrotron radiation sources; soft x-ray fluorescence spectroscopy using tunable synchrotron radiation; soft x-ray fluorescence spectroscopy excited by synchrotron radiation: Inelastic and resonant scattering near threshold; outer-shell photoionization of ions; overview of the APS BESSRC beamline development; the advanced light source: Research opportunities in atomic and molecular physics; Photoionization of the Ba + ion by 4d shell excitation; decay dynamics of inner-shell excited atoms and molecules; absorption of atomic Ca, Cr, Mn and Cu; High-resolution photoelectron studies of resonant molecular photoionization; radiative and radiationless resonant raman scattering by synchrotron radiation; auger spectrometry of atoms and molecules; some thoughts of future experiments with the new generation of storage rings; Electron spectroscopy studies of argon K-shell excitation and vacancy cascades; ionization of atoms by high energy photons; ion coincidence spectroscopy on rare gas atoms and small molecules after photoexcitation at energies of several keV; an EBIS for use with synchrotron radiation photoionization of multiply charged ions and PHOBIS; gamma-2e coincidence measurements the wave of the future in inner-shell electron spectroscopy; recoil momentum spectroscopy in ion-atom and photon-atom collisions; a study of compton ionization of helium; future perspectives of photoionization studies at high photon energies; and status report on the advanced photon source. These papers have been cataloged separately elsewhere

  19. Synthesis and novel fluorescence phenomenon of terbium(III) complex with N, N',N' -tris (2-benzimidazolmethyl) amine

    International Nuclear Information System (INIS)

    Yang, Tianlin; Gao, Min; Yang, Jinhui; Qin, Wenwu

    2010-01-01

    A benzimidazole ligand with a tripodal structure, N, N', N' -tris (2-benzimidazolmethyl) amine, and its terbium (III) complex has been synthesized. The complex has been characterized by element analysis, IR spectra, mass spectra, thermal analysis and molar conductivity. The terbium ion is found to coordinate with the nitrogen atoms (= N-) of imidazole ring and the bridgehead nitrogen atom. The fluorescence properties of the complex in aqueous solutions have been studied. Under excitation of UV light, the complex exhibits characteristic fluorescence of terbium ion. The luminescence of terbium complex in aqueous solutions is strongly enhanced by H + concentration. This phenomenon makes the new complex favorable for use in fluorescence switches and sensors. The mechanism of the fluorescence enhancement by protonation of the nitrogen atoms (-NH-) of imidazole ring is due to the suppressed photoinduced electron transfer fluorescence quenching on addition of acid. (author)

  20. Who's who in fluorescence 2008

    CERN Document Server

    Geddes, Chris D

    2008-01-01

    The Journal of Fluorescence's sixth Who's Who directory publishes the names, contact details, specialty keywords, and a brief description of scientists employing fluorescence methodology and instrumentation in their working lives. This is a unique reference.

  1. Plasma characterization using terahertz-wave-enhanced fluorescence

    International Nuclear Information System (INIS)

    Liu Jingle; Zhang, X.-C.

    2010-01-01

    We demonstrate that the terahertz-wave-enhanced fluorescence emission from excited atoms or molecules can be employed in the characterization of laser-induced gas plasmas. The electron relaxation time and plasma density were deduced through applying the electron impact excitation/ionization and electron-ion recombination processes to the measured time-dependent enhanced fluorescence. The electron collision dynamics of nitrogen plasma excited at different gas pressures and laser pulse energies have been systematically investigated. This plasma characterization method provides picosecond temporal resolution and enables omnidirectional optical signal collection.

  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. ADVANCED APPROACHES TO ARSINE ATOMIZATION FOR AS SPECIATION BY CRYOFOCUSING WITH ATOMIC ABSORPTION AND ATOMIC FLUORESCENCE DETECTORS

    Science.gov (United States)

    Human metabolism of inorganic arsenic (iAs) yields methylated arsenicals that contain arsenic in +3 or +5 oxidation state. Trivalent methylated arsenicals are significantly more toxic than their pentavalent counterparts. Therefore, determination of tri- and pentavalent forms of m...

  4. 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.

  5. Site-resolved imaging of a bosonic Mott insulator using ytterbium atoms

    Science.gov (United States)

    Miranda, Martin; Inoue, Ryotaro; Tambo, Naoki; Kozuma, Mikio

    2017-10-01

    We demonstrate site-resolved imaging of a strongly correlated quantum system without relying on laser cooling techniques during fluorescence imaging. We observe the formation of Mott shells in the insulating regime and realize thermometry in an atomic cloud. This work proves the feasibility of the noncooled approach and opens the door to extending the detection technology to new atomic species.

  6. Fluorescence spectroscopy of dental calculus

    International Nuclear Information System (INIS)

    Bakhmutov, D; Gonchukov, S; Sukhinina, A

    2010-01-01

    The aim of the present study was to investigate the fluorescence properties of dental calculus in comparison with the properties of adjacent unaffected tooth structure using both lasers and LEDs in the UV-visible range for fluorescence excitation. The influence of calculus color on the informative signal is demonstrated. The optimal spectral bands of excitation and registration of the fluorescence are determined

  7. Fluorescence spectroscopy of dental calculus

    Science.gov (United States)

    Bakhmutov, D.; Gonchukov, S.; Sukhinina, A.

    2010-05-01

    The aim of the present study was to investigate the fluorescence properties of dental calculus in comparison with the properties of adjacent unaffected tooth structure using both lasers and LEDs in the UV-visible range for fluorescence excitation. The influence of calculus color on the informative signal is demonstrated. The optimal spectral bands of excitation and registration of the fluorescence are determined.

  8. Fluorescence Imaging Reveals Surface Contamination

    Science.gov (United States)

    Schirato, Richard; Polichar, Raulf

    1992-01-01

    In technique to detect surface contamination, object inspected illuminated by ultraviolet light to make contaminants fluoresce; low-light-level video camera views fluorescence. Image-processing techniques quantify distribution of contaminants. If fluorescence of material expected to contaminate surface is not intense, tagged with low concentration of dye.

  9. Who's who in fluorescence 2005

    CERN Document Server

    Geddes, Chris D

    2006-01-01

    The Journal of Fluorescence's third Who's Who directory publishes the names, contact details, specialty keywords, photographs, and a brief description of scientists employing fluorescence methodology and instrumentation in their working livesThe directory provides company contact details with a brief list of fluorescence-related products.

  10. Laser-cooled atomic ions as probes of molecular ions

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Kenneth R.; Viteri, C. Ricardo; Clark, Craig R.; Goeders, James E.; Khanyile, Ncamiso B.; Vittorini, Grahame D. [Schools of Chemistry and Biochemistry, Computational Science and Engineering and Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2015-01-22

    Trapped laser-cooled atomic ions are a new tool for understanding cold molecular ions. The atomic ions not only sympathetically cool the molecular ions to millikelvin temperatures, but the bright atomic ion fluorescence can also serve as a detector of both molecular reactions and molecular spectra. We are working towards the detection of single molecular ion spectra by sympathetic heating spectroscopy. Sympathetic heating spectroscopy uses the coupled motion of two trapped ions to measure the spectra of one ion by observing changes in the fluorescence of the other ion. Sympathetic heating spectroscopy is a generalization of quantum logic spectroscopy, but does not require ions in the motional ground state or coherent control of the ion internal states. We have recently demonstrated this technique using two isotopes of Ca{sup +} [Phys. Rev. A, 81, 043428 (2010)]. Limits of the method and potential applications for molecular spectroscopy are discussed.

  11. X-ray holography. Atoms in three dimensions

    International Nuclear Information System (INIS)

    Tegze, M.

    2005-01-01

    The principles of atomic resolution X-ray holography was elaborated in 1991. X-ray photons scatter thousand times less on atoms than electrons of the same wavelength. As a result, both free path and penetration depth are higher which giver information about the bulk material. X-ray holography is realized by irradiating the single crystal sample with radiation from external X-ray source. The incident radiation is ionizing the atoms of the sample to emit fluorescent radiation. The angle dependence of the fluorescent radiation results an image containing the hologram. The hologram itself is extremely small compared to the background that needs 10 10 capturing photons to recover image. Using Thomas Gog's method and synchrotron radiation the X-ray holography becomes more usable, but the method still needs refining both experimentally and theoretically. (TRA)

  12. Fluorescence fluctuation spectroscopy (FFS)

    CERN Document Server

    Tetin, Sergey

    2012-01-01

    This new volume of Methods in Enzymology continues the legacy of this premier serial with quality chapters authored by leaders in the field. This volume covers fluorescence fluctuation spectroscopy and includes chapters on such topics as Förster resonance energy transfer (fret) with fluctuation algorithms, protein corona on nanoparticles by FCS, and FFS approaches to the study of receptors in live cells. Continues the legacy of this premier serial with quality chapters authored by leaders in the field Covers fluorescence fluctuation spectroscopy Contains chapters on such topics as Förster resonance energy transfer (fret) with fluctuation algorithms, protein corona on nanoparticles by FCS, and FFS approaches to the study of receptors in live cells.

  13. Fluorescent quantification of melanin.

    Science.gov (United States)

    Fernandes, Bruno; Matamá, Teresa; Guimarães, Diana; Gomes, Andreia; Cavaco-Paulo, Artur

    2016-11-01

    Melanin quantification is reportedly performed by absorption spectroscopy, commonly at 405 nm. Here, we propose the implementation of fluorescence spectroscopy for melanin assessment. In a typical in vitro assay to assess melanin production in response to an external stimulus, absorption spectroscopy clearly overvalues melanin content. This method is also incapable of distinguishing non-melanotic/amelanotic control cells from those that are actually capable of performing melanogenesis. Therefore, fluorescence spectroscopy is the best method for melanin quantification as it proved to be highly specific and accurate, detecting even small variations in the synthesis of melanin. This method can also be applied to the quantification of melanin in more complex biological matrices like zebrafish embryos and human hair. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Atomic collisions research with excited atomic species

    International Nuclear Information System (INIS)

    Hoogerland, M.D.; Gulley, R.J.; Colla, M.; Lu, W.; Milic, D.; Baldwin, K.G.H.; Buckman, S.J.

    1999-01-01

    Measurements and calculations of fundamental atomic collision and spectroscopic properties such as collision cross sections, reaction rates, transition probabilities etc. underpin the understanding and operation of many plasma and gas-discharge-based devices and phenomena, for example plasma processing and deposition. In almost all cases the complex series of reactions which sustains the discharge or plasma, or produces the reactive species of interest, has a precursor electron impact excitation, attachment, dissociation or ionisation event. These processes have been extensively studied in a wide range of atomic and molecular species and an impressive data base of collision cross sections and reaction rates now exists. However, most of these measurements are for collisions with stable atomic or molecular species which are initially in their ground electronic state. Relatively little information is available for scattering from excited states or for scattering from unstable molecular radicals. Examples of such species would be metastable excited rare gases, which are often used as buffer gases, or CF 2 radicals formed by electron impact dissociation in a CF 4 plasma processing discharge. We are interested in developing experimental techniques which will enable the quantitative study of such exotic atomic and molecular species. In this talk I would like to outline one such facility which is being used for studies of collisions with metastable He(2 3 S) atoms

  15. 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.)

  16. Time-resolved laser-induced fluorescence system

    Science.gov (United States)

    Bautista, F. J.; De la Rosa, J.; Gallegos, F. J.

    2006-02-01

    Fluorescence methods are being used increasingly in the measurement of species concentrations in gases, liquids and solids. Laser induced fluorescence is spontaneous emission from atoms or molecules that have been excited by laser radiation. Here we present a time resolved fluorescence instrument that consists of a 5 μJ Nitrogen laser (337.1 nm), a sample holder, a quartz optical fiber, a spectrometer, a PMT and a PC that allows the measurement of visible fluorescence spectra (350-750 nm). Time response of the system is approximately 5 ns. The instrument has been used in the measurement of colored bond paper, antifreeze, diesel, cochineal pigment and malignant tissues. The data acquisition was achieved through computer control of a digital oscilloscope (using General Purpose Interface Bus GPIB) and the spectrometer via serial (RS232). The instrument software provides a graphic interface that lets make some data acquisition tasks like finding fluorescence spectra, and fluorescence lifetimes. The software was developed using the Lab-View 6i graphic programming package and can be easily managed in order to add more functions to it.

  17. Surface plasmon-enhanced molecular fluorescence induced by gold nanostructures

    International Nuclear Information System (INIS)

    Teng, Y.; Ueno, K.; Shi, X.; Aoyo, D.; Misawa, H.; Qiu, J.

    2012-01-01

    The authors report on surface plasmon-enhanced fluorescence of Eosin Y molecules induced by gold nanostructures. Al 2 O 3 films deposited by atomic layer deposition with sub-nanometer resolution were used as the spacer layer to control the distance between molecules and the gold surface. As the thickness of the Al 2 O 3 film increased, the fluorescence intensity first increased and then decreased. The highest enhancement factor is achieved with a 1 nm Al 2 O 3 film. However, the trend for the fluorescence lifetime is the opposite. It first decreased and then increased. The changes in the fluorescence quantum yield were also calculated. The yield shows a similar trend to the fluorescence intensity. The competition between the surface plasmon-induced increase in the radiative decay rate and the gold-induced fluorescence quenching is responsible for the observed phenomenon. In addition, this competition strongly depends on the thickness of the spacer layer between Eosin Y molecules and the gold surface. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Spectroscopy and nonclassical fluorescence properties of single trapped Ba+ ions

    International Nuclear Information System (INIS)

    Bolle, J.

    1998-06-01

    This thesis reports on the setup and application of an experimental apparatus for spectroscopic and quantum optical investigations of a single Barium ion in a Paul trap. The realization of the apparatus, which consists of the ion trap in ultra high vacuum, two laser systems, and a photon counting detection system, is described in detail, with particular consideration of the noise sources like stray light and laser frequency instabilities. The two lasers at 493 nm and 650 nm needed to continuously excite resonance fluorescence from the Barium ion have been realized using diode lasers only. The preparation of a single localized Barium ion is described, in particular its optical cooling with the laser light and the minimization of induced vibration in the trapping potential. The purely quantum mechanical property of antibunching is observed by measuring the intensity correlation function of resonance fluorescence from the trapped and cooled ion. Interference properties of the single ion resonance fluorescence are investigated with a Mach-Zehnder interferometer. From the measured high-contrast interference signal it is proven that each individual fluorescence photon interferes with itself. The fluorescence excitation spectrum, on varying one laser frequency, is also measured and exhibits dark resonances. These measurements are compared to calculations based on optical Bloch equations for the 8 atomic levels involved. Future experiments, in particular the detection of reduced quantum fluctuations (squeezing) in one quadrature component of the resonance fluorescence, are discussed. (author)

  19. Atoms - molecules - nuclei. Vol. 1

    International Nuclear Information System (INIS)

    Otter, G.; Honecker, R.

    1993-01-01

    This first volume covers the following topics: Wave-particle dualism, classical atomic physics; the Schroedinger equation, angular momentum in quantum physics, one-electron atoms and many-electron atoms with atomic structure, atomic spectra, exotic atoms, influence of electric and magnetic fields

  20. Fluorescent nanodiamond for biomedicine

    International Nuclear Information System (INIS)

    Milos Nesladek

    2014-01-01

    NV centers in diamond have gained strong interest as a novel tool for quantum information processing, quantum computing and quantum photonics. These applications are based on fluorescent and spin properties of NV-centres. However, in some conditions NV- can lose an electron and turn to NV0. The occupation of NV0 and NV- charge states depend on the position of their ground states with respect to the Fermi level and the mechanism of the charge transfer. Interestingly, that the charge switch has important implications on applications of fluorescent nanodiamond (fND) to nano-biology and nano-medicine. fND can be used for bio-marking and bio-tracking but also for the monitoring of targeted delivery to the cells. In this presentation we review the current state-of-the art for using fND particles for fluorescent bio imaging in cells and discuss the charge transfer and its luminescence stability by using ultra high sensitive spectroscopy methods to study the NV0 and NV- state occupation. (author)

  1. Barium transport in the hot spot region of fluorescent lamps

    International Nuclear Information System (INIS)

    Sigeneger, F; Rackow, K; Uhrlandt, D; Ehlbeck, J; Lieder, G

    2010-01-01

    The transport of barium atoms and ions in the vicinity of the hot spot in fluorescent lamps operating at 25 kHz is investigated by a combined experimental and theoretical approach. By laser-induced fluorescence, the particle densities of barium atoms and ions were measured time-resolved at different distances from the spot centre. In addition, the time-dependent cathode fall voltage was measured using an improved band method. The model combines a kinetic part for the electrons with a fluid part for the barium atoms and ions. Both parts are spatially resolved in spherically symmetric geometry. The space-dependent electron Boltzmann equation yields the electron density and the ionization rate coefficient of barium as functions of the cathode fall voltage. These results are used to solve the time-dependent particle balance equations of barium atoms and ions which include the ionization of barium as gain and loss terms, respectively. Good agreement between the measured and calculated particle densities of barium atoms is obtained. A sensitive dependence of the ionization frequency and of the barium particle densities on the cathode fall voltage was found.

  2. Atomic carbon emission from photodissociation of CO2. [planetary atmospheric chemistry

    Science.gov (United States)

    Wu, C. Y. R.; Phillips, E.; Lee, L. C.; Judge, D. L.

    1978-01-01

    Atomic carbon fluorescence, C I 1561, 1657, and 1931 A, has been observed from photodissociation of CO2, and the production cross sections have been measured. A line emission source provided the primary photons at wavelengths from threshold to 420 A. The present results suggest that the excited carbon atoms are produced by total dissociation of CO2 into three atoms. The cross sections for producing the O I 1304-A fluorescence through photodissociation of CO2 are found to be less than 0.01 Mb in the wavelength region from 420 to 835 A. The present data have implications with respect to photochemical processes in the atmospheres of Mars and Venus.

  3. Techniques of laser spectroscopy in investigations of lanthanides' free atoms and ions

    International Nuclear Information System (INIS)

    Furmann, B.; Szawiola, G.; Jarosz, A.; Krzykowski, A.; Stefanska, D.; Dembczynski, J.

    2010-01-01

    Various experimental methods, used in Chair of Quantum Engineering and Metrology for determination of the hyperfine structure of electronic levels in lanthanides atoms and ions, are presented. In turn the spectroscopic methods on an atomic beam (laser induced fluorescence and laser-rf double resonance ABMR-LIRF), laser-rf double resonance in a Paul trap and spectroscopic methods in a hollow cathode discharge (optogalvanic detection and laser induced fluorescence) are presented. Each method has been characterized with its potential accuracy and domain of application. The results achieved for the atoms and the ions of lanthanum, praseodymium, neodymium and europium have been published in numerous articles (compiled in the reference list).

  4. Atomic and molecular sciences

    International Nuclear Information System (INIS)

    Lane, N.F.

    1989-01-01

    The theoretical atomic and molecular physics program at Rice University addresses basic questions about the collision dynamics of electrons, atoms, ions and molecules, emphasizing processes related to possible new energy technologies and other applications. The program focuses on inelastic collision processes that are important in understanding energy and ionization balance in disturbed gases and plasmas. Emphasis is placed on systems and processes where some experimental information is available or where theoretical results may be expected to stimulate new measurements. Examples of current projects include: excitation and charge-transfer processes; orientation and alignment of excited states following collisions; Rydberg atom collisions with atoms and molecules; Penning ionization and ion-pair formation in atom-atom collisions; electron-impact ionization in dense, high-temperature plasmas; electron-molecule collisions; and related topics

  5. 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.

  6. Metal atom oxidation laser

    International Nuclear Information System (INIS)

    Jensen, R.J.; Rice, W.W.; Beattie, W.H.

    1975-01-01

    A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides

  7. 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.

  8. Economical Atomic Layer Deposition

    Science.gov (United States)

    Wyman, Richard; Davis, Robert; Linford, Matthew

    2010-10-01

    Atomic Layer Deposition is a self limiting deposition process that can produce films at a user specified height. At BYU we have designed a low cost and automated atomic layer deposition system. We have used the system to deposit silicon dioxide at room temperature using silicon tetrachloride and tetramethyl orthosilicate. Basics of atomic layer deposition, the system set up, automation techniques and our system's characterization are discussed.

  9. Atomic physics made clear

    International Nuclear Information System (INIS)

    Meinhold, H.

    1980-01-01

    This book is a popular introduction into the foundations of atomic physics und quantum mechanics. Starting from some phenomenological concepts Bohr's model and the construction of the periodic system regarding the shell structure of atoms are introduced. In this framework the selection rules and magnetic moments of atomic electrons are considered. Finally the wave-particle dualism is considered. In the appendix some mathematical methods are described which are useful for a deeper penetration into the considered ideas. (HSI)

  10. Deeply bound pionic atom

    International Nuclear Information System (INIS)

    Toki, Hiroshi; Yamazaki, Toshimitsu

    1989-01-01

    The standard method of pionic atom formation does not produce deeply bound pionic atoms. A study is made on the properties of deeply bound pionic atom states by using the standard pion-nucleus optical potential. Another study is made to estimate the cross sections of the formation of ls pionic atom states by various methods. The pion-nucleus optical potential is determined by weakly bound pionic atom states and pion nucleus scattering. Although this potential may not be valid for deeply bound pionic atoms, it should provide some hint on binding energies and level widths of deeply bound states. The width of the ls state comes out to be 0.3 MeV and is well separated from the rest. The charge dependence of the ls state is investigated. The binding energies and the widths increase linearly with Z azbove a Z of 30. The report then discusses various methods to populate deeply bound pionic atoms. In particular, 'pion exchange' reactions are proposed. (n, pπ) reaction is discussed first. The cross section is calculated by assuming the in- and out-going nucleons on-shell and the produced pion in (n1) pionic atom states. Then, (n, dπ - ) cross sections are estimated. (p, 2 Heπ - ) reaction would have cross sections similar to the cross section of (n, dπ - ) reaction. In conclusion, it seems best to do (n, p) experiment on heavy nuclei for deeply bound pionic atom. (Nogami, K.)

  11. Atomic hydrogen reactor

    International Nuclear Information System (INIS)

    Massip de Turville, C.M.D.

    1982-01-01

    Methods are discussed of generating heat in an atomic hydrogen reactor which involve; the production of atomic hydrogen by an electrical discharge, the capture of nascent neutrons from atomic hydrogen in a number of surrounding steel alloy tubes having a high manganese content to produce 56 Mn, the irradiation of atomic hydrogen by the high energy antineutrinos from the beta decay of 56 Mn to yield nascent neutrons, and the removal of the heat generated by the capture of nascent neutrons by 55 Mn and the beta decay of 56 Mn. (U.K.)

  12. Correlated quadratures of resonance fluorescence and the generalized uncertainty relation

    Science.gov (United States)

    Arnoldus, Henk F.; George, Thomas F.; Gross, Rolf W. F.

    1994-01-01

    Resonance fluorescence from a two-state atom has been predicted to exhibit quadrature squeezing below the Heisenberg uncertainty limit, provided that the optical parameters (Rabi frequency, detuning, laser linewidth, etc.) are chosen carefully. When the correlation between two quadratures of the radiation field does not vanish, however, the Heisenberg limit for quantum fluctuations might be an unrealistic lower bound. A generalized uncertainty relation, due to Schroedinger, takes into account the possible correlation between the quadrature components of the radiation, and it suggests a modified definition of squeezing. We show that the coherence between the two levels of a laser-driven atom is responsible for the correlation between the quadrature components of the emitted fluorescence, and that the Schrodinger uncertainty limit increases monotonically with the coherence. On the other hand, the fluctuations in the quadrature field diminish with an increasing coherence, and can disappear completely when the coherence reaches 1/2, provided that certain phase relations hold.

  13. Principle and Reconstruction Algorithm for Atomic-Resolution Holography

    Science.gov (United States)

    Matsushita, Tomohiro; Muro, Takayuki; Matsui, Fumihiko; Happo, Naohisa; Hosokawa, Shinya; Ohoyama, Kenji; Sato-Tomita, Ayana; Sasaki, Yuji C.; Hayashi, Kouichi

    2018-06-01

    Atomic-resolution holography makes it possible to obtain the three-dimensional (3D) structure around a target atomic site. Translational symmetry of the atomic arrangement of the sample is not necessary, and the 3D atomic image can be measured when the local structure of the target atomic site is oriented. Therefore, 3D local atomic structures such as dopants and adsorbates are observable. Here, the atomic-resolution holography comprising photoelectron holography, X-ray fluorescence holography, neutron holography, and their inverse modes are treated. Although the measurement methods are different, they can be handled with a unified theory. The algorithm for reconstructing 3D atomic images from holograms plays an important role. Although Fourier transform-based methods have been proposed, they require the multiple-energy holograms. In addition, they cannot be directly applied to photoelectron holography because of the phase shift problem. We have developed methods based on the fitting method for reconstructing from single-energy and photoelectron holograms. The developed methods are applicable to all types of atomic-resolution holography.

  14. Atom dynamics in laser fields

    International Nuclear Information System (INIS)

    Jang, Su; Mi, No Gin

    2004-12-01

    This book introduces coherent dynamics of internal state, spread of atoms wave speed, semiclassical atoms density matrix such as dynamics equation in both still and moving atoms, excitation of atoms in movement by light, dipole radiating power, quantum statistical mechanics by atoms in movement, semiclassical atoms in movement, atoms in movement in the uniform magnetic field including effects of uniform magnetic field, atom cooling using laser such as Doppler cooling, atom traps using laser and mirrors, radiant heat which particles receive, and near field interactions among atoms in laser light.

  15. Localization of atomic ensembles via superfluorescence

    International Nuclear Information System (INIS)

    Macovei, Mihai; Evers, Joerg; Keitel, Christoph H.; Zubairy, M. Suhail

    2007-01-01

    The subwavelength localization of an ensemble of atoms concentrated to a small volume in space is investigated. The localization relies on the interaction of the ensemble with a standing wave laser field. The light scattered in the interaction of the standing wave field and the atom ensemble depends on the position of the ensemble relative to the standing wave nodes. This relation can be described by a fluorescence intensity profile, which depends on the standing wave field parameters and the ensemble properties and which is modified due to collective effects in the ensemble of nearby particles. We demonstrate that the intensity profile can be tailored to suit different localization setups. Finally, we apply these results to two localization schemes. First, we show how to localize an ensemble fixed at a certain position in the standing wave field. Second, we discuss localization of an ensemble passing through the standing wave field

  16. 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.

  17. Copper spherical cavity arrays: Fluorescence enhancement in PFO films

    Energy Technology Data Exchange (ETDEWEB)

    Spada, Edna R., E-mail: edspada@gmail.com [Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970, São Carlos, SP (Brazil); Valente, Gustavo T.; Pereira-da-Silva, Marcelo A. [Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970, São Carlos, SP (Brazil); Sartorelli, Maria L. [Departamento de Física, Universidade Federal de Santa Catarina, Caixa Postal 476, 88040-900, Florianópolis, SC (Brazil); Guimarães, Francisco E.G.; Faria, Roberto M. [Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970, São Carlos, SP (Brazil)

    2017-01-15

    This manuscript addresses the use of a well-ordered antidot copper nanostructure as a active substrate for surface enhancement fluorescence (SEF). The antidot array was produced by electrodeposition and nanosphere lithography and characterized by microscopy technique, its successful application as SEF-active substrates was verified using polyfluorene (PFO) as a probe layer. Atomic force microscopy (AFM) was used to evaluate the regularity of the metal surface as well PFO coated process and confocal laser fluorescence microscopy (CLSM) to determine the behavior exhibited by the fluorescent layer due to the existence of the nanostructured surface. No accumulation PFO in the cavities was detected and the more intense emission regions coincides with the position of the cavities and is at about one order of magnitude higher.

  18. Atoms stories; Histoire d`atomes

    Energy Technology Data Exchange (ETDEWEB)

    Radvanyi, P; Bordry, M [Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France)

    1988-12-31

    Physicists from different countries told each evening during one learning week, to an audience of young people, some great discoveries in evoking the difficulties and problems to which the researchers were confronted. From Antiquity to a more recent history, it is a succession of atoms stories. (N.C.)

  19. Low energy atom-atom collisions

    International Nuclear Information System (INIS)

    Child, M.S.

    1980-01-01

    The semiclassical theory of atom-atom potential scattering and of low energy inelastic atom-atom scattering is reviewed. Particular attention is given to the origin and interpretation of rainbow structure, diffraction oscillations and exchange oscillations in the potential scattering differential cross-section, and to the glory structure and symmetry oscillations in the integral cross-section. Available methods for direct inversion of the cross-section data to recover the potential are reviewed in some detail. The theory of non-adiabatic transitions is introduced by a short discussion of interaction mechanisms and of diabetic and adiabatic representations. Analytical S matrix elements are presented for two state curve-crossing (Landau-Zener-Stuckelberg), Demkov and Nikitin models. The relation between Stuckelberg oscillations in the S matrix and in the differential cross-section is discussed in terms of interference between trajectories belonging to two different classical deflection functions. The energy dependences of the inelastic integral cross-section for curve-crossing and Demkov type transitions are also discussed. Finally the theory is reviewed in relation to a recent close-coupled study of fine structure transitions in F( 2 P) + Xe( 2 S) scattering

  20. 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.

  1. Atomic Energy Control Board

    International Nuclear Information System (INIS)

    Blackman, N.S.; Gummer, W.K.

    1982-02-01

    This paper has been prepared to provide an overview of the responsibilities and activities of the Atomic Energy Control Board. It is designed to address questions that are often asked concerning the establishment of the Atomic Energy Control Board, its enabling legislation, licensing and compliance activities, federal-provincial relationships, international obligations, and communications with the public

  2. mu. -nucleon atoms

    Energy Technology Data Exchange (ETDEWEB)

    Dobretsov, Yu; Dolgoshein, B; Kirillov-Ugryumov, V

    1980-12-01

    The properties and formation are described of ..mu..-nucleon atoms, the Larmor method of muon spin precession is discussed and the experimental confirmation of the existence of ..mu..-nucleon atoms is shown. The prospects of their use are indicated.

  3. μ-nucleon atoms

    International Nuclear Information System (INIS)

    Dobretsov, Yu.; Dolgoshejn, B.; Kirillov-Ugryumov, V.

    1980-01-01

    The properties and formation are described of μ-nucleon atoms, the Larmor method of muon spin precession is discussed and the experimental confirmation of the existence of μ-nucleon atoms is shown. The prospects of their use are indicated. (J.P.)

  4. Atomic Ferris wheel beams

    Science.gov (United States)

    Lembessis, Vasileios E.

    2017-07-01

    We study the generation of atom vortex beams in the case where a Bose-Einstein condensate, released from a trap and moving in free space, is diffracted from a properly tailored light mask with a spiral transverse profile. We show how such a diffraction scheme could lead to the production of an atomic Ferris wheel beam.

  5. Atom lithography of Fe

    NARCIS (Netherlands)

    Sligte, te E.; Smeets, B.; van der Stam, K.M.R.; Herfst, R.W.; Straten, van der P.; Beijerinck, H.C.W.; Leeuwen, van K.A.H.

    2004-01-01

    Direct write atom lithography is a technique in which nearly resonant light is used to pattern an atom beam. Nanostructures are formed when the patterned beam falls onto a substrate. We have applied this lithography scheme to a ferromagnetic element, using a 372 nm laser light standing wave to

  6. Beyond the Atom

    Science.gov (United States)

    Cox, John

    2011-08-01

    1. Introduction - the atom in the seventies; 2. The vacuum tube; 3. The new rays; 4. The new substances; 5. Disintegration; 6. A family tree; 7. Verifications and results; 8. The objective reality of molecules; 9. The new atom; Bibliography; Index.

  7. 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…

  8. Atom electron scattering

    International Nuclear Information System (INIS)

    Santoso, B.

    1976-01-01

    Green Lippmann-Schwinger functions operator representations, derivation of perturbation method using Green function and atom electron scattering, are discussed. It is concluded that by using complex coordinate places where resonances occur, can be accurately identified. The resonance can be processed further for practical purposes, for example for the separation of atom. (RUW)

  9. Atomic energy for progress

    International Nuclear Information System (INIS)

    1974-01-01

    The film discusses the functions and activities of the Philippine Atomic Energy Commission. Shown are the applications of atomic energy in research, agriculture, engineering, industry and medicine, as well as the construction of the research reactor and its inauguration by President Marcos

  10. Zeeman atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    Loos-Vollebregt, M.T.C. de.

    1980-01-01

    A new method of background correction in atomic absorption spectroscopy has recently been introduced, based on the Zeeman splitting of spectral lines in a magnetic field. A theoretical analysis of the background correction capability observed in such instruments is presented. A Zeeman atomic absorption spectrometer utilizing a 50 Hz sine wave modulated magnetic field is described. (Auth.)

  11. Isotopes and atomic weights

    International Nuclear Information System (INIS)

    Zhang Qinglian

    1990-01-01

    A review of the chemical and mass spectrometric methods of determining the atomic weights of elements is presented. A, special discussion is devoted to the calibration of the mass spectrometer with highly enriched isotopes. It is illustrated by the recent work on europium. How to choose the candidate element for new atomic weight determination forms the last section of the article

  12. Fluorescent microthermographic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Barton, D.L.

    1993-09-01

    In the early days of microelectronics, design rules and feature sizes were large enough that sub-micron spatial resolution was not needed. Infrared or IR thermal techniques were available that calculated the object`s temperature from infrared emission. There is a fundamental spatial resolution limitation dependent on the wavelengths of light being used in the image formation process. As the integrated circuit feature sizes began to shrink toward the one micron level, the limitations imposed on IR thermal systems became more pronounced. Something else was needed to overcome this limitation. Liquid crystals have been used with great success, but they lack the temperature measurement capabilities of other techniques. The fluorescent microthermographic imaging technique (FMI) was developed to meet this need. This technique offers better than 0.01{degrees}C temperature resolution and is diffraction limited to 0.3 {mu}m spatial resolution. While the temperature resolution is comparable to that available on IR systems, the spatial resolution is much better. The FMI technique provides better spatial resolution by using a temperature dependent fluorescent film that emits light at 612 nm instead of the 1.5 {mu}m to 12 {mu}m range used by IR techniques. This tutorial starts with a review of blackbody radiation physics, the process by which all heated objects emit radiation to their surroundings, in order to understand the sources of information that are available to characterize an object`s surface temperature. The processes used in infrared thermal imaging are then detailed to point out the limitations of the technique but also to contrast it with the FMI process. The FMI technique is then described in detail, starting with the fluorescent film physics and ending with a series of examples of past applications of FMI.

  13. 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...

  14. 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...

  15. Antiprotonic-hydrogen atoms

    International Nuclear Information System (INIS)

    Batty, C.J.

    1989-07-01

    Experimental studies of antiprotonic-hydrogen atoms have recently made great progress following the commissioning of the low energy antiproton facility (LEAR) at CERN in 1983. At the same time our understanding of the atomic cascade has increased considerably through measurements of the X-ray spectra. The life history of the p-bar-p atom is considered in some detail, from the initial capture of the antiproton when stopping in hydrogen, through the atomic cascade with the emission of X-rays, to the final antiproton annihilation and production of mesons. The experiments carried out at LEAR are described and the results compared with atomic cascade calculations and predictions of strong interaction effects. (author)

  16. Direct Frequency Comb Spectroscopy of Alkali Atoms

    Science.gov (United States)

    Pradhananga, Trinity; Palm, Christopher; Nguyen, Khoa; Guttikonda, Srikanth; Kimball, Derek Jackson

    2011-11-01

    We are using direct frequency comb spectroscopy to study transition frequencies and excited state hyperfine structure in potassium and rubidium using 2-photon transitions excited directly with the frequency-doubled output of a erbium fiber optical frequency comb. The frequency comb output is directed in two counterpropagating directions through a vapor cell containing the atomic vapor of interest. A pair of optical filters is used to select teeth of the comb in order to identify the transition wavelengths. A photomultiplier tube (PMT) measures fluorescence from a decay channel wavelength selected with another optical filter. Using different combinations of filters enables a wide range of transitions to be investigated. By scanning the repetition rate, a Doppler-free spectrum can be obtained enabling kHz-resolution spectral measurements. The thermal motion of the atoms in the vapor cell actually eliminates the need to fine-tune the offset frequency and repetition rate, alleviating a somewhat challenging requirement for spectroscopy of cold atoms. Our investigations are laying the groundwork for a long-term research program to use direct frequency comb spectroscopy to understand the complex spectra of rare-earth atoms.

  17. A fluorescence scanning electron microscope

    International Nuclear Information System (INIS)

    Kanemaru, Takaaki; Hirata, Kazuho; Takasu, Shin-ichi; Isobe, Shin-ichiro; Mizuki, Keiji; Mataka, Shuntaro; Nakamura, Kei-ichiro

    2009-01-01

    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.

  18. Development of a fluorescent cryocooler

    International Nuclear Information System (INIS)

    Edwards, B.C.; Buchwald, M.I.; Epstein, R.I.; Gosnell, T.R.; Mungan, C.E.

    1995-01-01

    Recent work at Los Alamos National Laboratory has demonstrated the physical principles for a new type of solid-state cryocooler based on anti-Stokes fluorescence. Design studies indicate that a vibration-free, low-mass ''fluorescent cryocooler'' could operate for years with efficiencies and cooling powers comparable to current commercial systems. This paper presents concepts for a fluorescent cryocooler, design considerations and expected performance

  19. Fluorescence of ceramic color standards

    International Nuclear Information System (INIS)

    Koo, Annette; Clare, John F.; Nield, Kathryn M.; Deadman, Andrew; Usadi, Eric

    2010-01-01

    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.

  20. Simulation study of two-energy X-ray fluorescence holograms reconstruction algorithm to remove twin images

    International Nuclear Information System (INIS)

    Xie Honglan; Hu Wen; Luo Hongxin; Deng Biao; Du Guohao; Xue Yanling; Chen Rongchang; Shi Shaomeng; Xiao Tiqiao

    2008-01-01

    Unlike traditional outside-source holography, X-ray fluorescence holography is carded out with fluorescent atoms in a sample as source light for holographic imaging. With the method, three-dimensional arrangement of atoms into crystals can be observed obviously. However, just like traditional outside-source holography, X-ray fluorescence holography suffers from the inherent twin-image problem, too. With a 27-Fe-atoms cubic lattice as model, we discuss in this paper influence of the photon energy of incident source in removing twin images in reconstructed atomic images by numerical simulation and reconstruction with two-energy X-ray fluorescence holography. The results indicate that incident X-rays of nearer energies have better effect of removing twin images. In the detector of X-ray holography, minimum difference of the two incident energies depends on energy resolution of the monochromator and detector, and for inside source X-ray holography, minimum difference of the two incident energies depends on difference of two neighboring fluorescent energies emitting from the element and energy resolution of detector. The spatial resolution of atomic images increases with the incident energies. This is important for experiments of X-ray fluorescence holography, which is being developed on Shanghai Synchrotron Radiation Facility. (authors)

  1. Experimental atomic physics

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    The experimental atomic physics program within the physics division is carried out by two groups, whose reports are given in this section. Work of the accelerator atomic physics group is centered around the 6.5-MV EN tandem accelerator; consequently, most of its research is concerned with atomic processes occurring to, or initiated by, few MeV/amu heavy ions. Other activities of this group include higher energy experiments at the Holifield Heavy Ion Research Facility (HHIRF), studies of electron and positron channeling radiation, and collaborative experiments at other institutions. The second experimental group concerns itself with lower energy atomic collision physics in support of the Fusion Energy Program. During the past year, the new Electron Cyclotron Resonance Source has been completed and some of the first data from this facility is presented. In addition to these two activities in experimental atomic physics, other chapters of this report describe progress in theoretical atomic physics, experimental plasma diagnostic development, and atomic data center compilation activities

  2. Optically trapped atomic resonant devices for narrow linewidth spectral imaging

    Science.gov (United States)

    Qian, Lipeng

    This thesis focuses on the development of atomic resonant devices for spectroscopic applications. The primary emphasis is on the imaging properties of optically thick atomic resonant fluorescent filters and their applications. In addition, this thesis presents a new concept for producing very narrow linewidth light as from an atomic vapor lamp pumped by a nanosecond pulse system. This research was motivated by application for missile warning system, and presents an innovative approach to a wide angle, ultra narrow linewidth imaging filter using a potassium vapor cell. The approach is to image onto and collect the fluorescent photons emitted from the surface of an optically thick potassium vapor cell, generating a 2 GHz pass-band imaging filter. This linewidth is narrow enough to fall within a Fraunhefer dark zone in the solar spectrum, thus make the detection solar blind. Experiments are conducted to measure the absorption line shape of the potassium resonant filter, the quantum efficiency of the fluorescent behavior, and the resolution of the fluorescent image. Fluorescent images with different spatial frequency components are analyzed by using a discrete Fourier transform, and the imaging capability of the fluorescent filter is described by its Modulation Transfer Function. For the detection of radiation that is spectrally broader than the linewidth of the potassium imaging filter, the fluorescent image is seen to be blurred by diffuse fluorescence from the slightly off resonant photons. To correct this, an ultra-thin potassium imaging filter is developed and characterized. The imaging property of the ultra-thin potassium imaging cell is tested with a potassium seeded flame, yielding a resolution image of ˜ 20 lines per mm. The physics behind the atomic resonant fluorescent filter is radiation trapping. The diffusion process of the resonant photons trapped in the atomic vapor is theoretically described in this thesis. A Monte Carlo method is used to simulate the

  3. Entangled photons from single atoms and molecules

    Science.gov (United States)

    Nordén, Bengt

    2018-05-01

    The first two-photon entanglement experiment performed 50 years ago by Kocher and Commins (KC) provided isolated pairs of entangled photons from an atomic three-state fluorescence cascade. In view of questioning of Bell's theorem, data from these experiments are re-analyzed and shown sufficiently precise to confirm quantum mechanical and dismiss semi-classical theory without need for Bell's inequalities. Polarization photon correlation anisotropy (A) is useful: A is near unity as predicted quantum mechanically and well above the semi-classic range, 0 ⩽ A ⩽ 1 / 2 . Although yet to be found, one may envisage a three-state molecule emitting entangled photon pairs, in analogy with the KC atomic system. Antibunching in fluorescence from single molecules in matrix and entangled photons from quantum dots promise it be possible. Molecules can have advantages to parametric down-conversion as the latter photon distribution is Poissonian and unsuitable for producing isolated pairs of entangled photons. Analytical molecular applications of entangled light are also envisaged.

  4. X-ray fluorescence holography: A different approach to data collection

    International Nuclear Information System (INIS)

    Busetto, E.; Kopecky, M.; Lausi, A.; Menk, R.H.; Miculin, M.; Savoia, A.

    2000-01-01

    The images of nearest neighbors of gallium atoms in a GaAs crystal were obtained by the x-ray fluorescence holography technique. The fluorescence from gallium atoms was selected by means of a thin zinc foil filter that made possible the use of an x-ray silicon photodiode detector without energy resolution. This method makes possible the detection of a much higher signal with respect to all previous experiments, thus reducing drastically measuring times, that is a basic and essential step from contemporary demonstration experiments to possible practical applications of x-ray holography in structure analysis

  5. Atomic mass spectrometry

    International Nuclear Information System (INIS)

    Sanz-Medel, A.

    1997-01-01

    The elemental inorganic analysis seems to be dominated today by techniques based on atomic spectrometry. After an evaluation of advantages and limitations of using mass analysers (ion detectors) versus conventional photomultipliers (photon detector) a brief review of the more popular techniques of the emerging Atomic Mass spectrometry is carried out. Their huge potential for inorganic trace analysis is such that in the future we could well witness how this end of the century and millennium marked the fall of the photons empire in Analytical Atomic Spectrometry. (Author)

  6. 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.

  7. 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.

  8. Division of atomic physics

    International Nuclear Information System (INIS)

    Kroell, S.

    1994-01-01

    The Division of Atomic Physics, Lund Institute of Technology (LTH), is responsible for the basic physics teaching in all subjects at LTH and for specialized teaching in Optics, Atomic Physics, Atomic and Molecular Spectroscopy and Laser Physics. The Division has research activities in basic and applied optical spectroscopy, to a large extent based on lasers. It is also part of the Physics Department, Lund University, where it forms one of eight divisions. Since the beginning of 1980 the research activities of our division have been centred around the use of lasers. The activities during the period 1991-1992 is described in this progress reports

  9. Atom trap trace analysis

    International Nuclear Information System (INIS)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O'Connor, T. P.; Young, L.

    2000-01-01

    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 85 Kr and 81 Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10 -11 and 10 -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

  10. Photodesorption of Na atoms from rough Na surfaces

    DEFF Research Database (Denmark)

    Balzer, Frank; Gerlach, R.; Manson, J.R.

    1997-01-01

    We investigate the desorption of Na atoms from large Na clusters deposited on dielectric surfaces. High-resolution translational energy distributions of the desorbing atoms are determined by three independent methods, two-photon laser-induced fluorescence, as well as single-photon and resonance......-enhanced two-photon ionization techniques. Upon variation of surface temperature and for different substrates (mica vs lithium fluoride) clear non-Maxwellian time-of-flight distributions are observed with a cos θ angular dependence and most probable kinetic energies below that expected of atoms desorbing from...... atoms are scattered by surface vibrations. Recent experiments providing time constants for the decay of the optical excitations in the clusters support this model. The excellent agreement between experiment and theory indicates the importance of both absorption of the laser photons via direct excitation...

  11. Section of Atomic Collisions

    International Nuclear Information System (INIS)

    Berenyi, D.; Biri, S.; Gulyas, L.; Juhasz, Z.; Kover, A.; Orban, A.; Palinkas, J.; Papp, T.; Racz, R.; Ricz, S.

    2009-01-01

    The Section of Atomic Collisions is a research unit with extended activity in the field of atomic and molecular physics. Starting from the study of atomic processes at the beamlines of nuclear physics accelerators in the seventies, our research community became one of the centers of fundamental research in Atomki. We also have a strong connection to materials sciences especially along the line of electron and ion spectroscopy methods. Our present activity covers a wide range of topics from atomic collision mechanisms of fundamental interest, to the complex interactions of electrons, ions, photons and antiparticles with atoms, molecules, surfaces, and specific nanostructures. In the last few years, an increasing fraction of our present topics has become relevant for applications, e.g., molecular collision studies for the radiation therapy methods of tumors, or ion-nanostructure interactions for the future construction of small ion-focusing elements. Our section belongs to the Division of Atomic Physics. The other unit of the Division is the Section of Electron Spectroscopy and Materials Sciences. There are traditionally good connections and a strong collaboration between the groups of the two sections in many fields. From the very beginning of our research work in atomic collisions, external collaborations were of vital importance for us. We regularly organize international workshops in the field of fast ion-atom collisions and related small conferences in Debrecen from 1981. Recently, we organized the Conference on Radiation Damage in Biomolecular Systems (RADAM 2008, Debrecen), and coorganized the Conference on Elementary Processes in Atomic Systems (CEPAS 2008, Cluj). We have access to several large scale facilities in Europe within the framework of formal and informal collaborations. The next themes are in this article: Forward electron emission from energetic atomic collisions; Positron-atom collisions; Photon-atom interactions; Interference effects in electron

  12. History of early atomic clocks

    International Nuclear Information System (INIS)

    Ramsey, N.F.

    2005-01-01

    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)

  13. A guide for approval of x-ray fluorescence analysis devices

    International Nuclear Information System (INIS)

    1990-01-01

    This guide has been written to assist manufacturers, distributors and users of x-ray fluorescence analysis devices in the preparation of a submission to the Atomic Energy Control Board (AECB) in support of a request for approval of an x-ray fluorescence analysis device. Prior to the issuance of a Radioisotope licence authorizing the use or possession of an x-ray fluorescence analysis device in Canada, the design and construction of the device must be approved by the AECB. The AECB assessment is limited to the radiation safety aspects of use and packaging for transportation

  14. Examinations for the determination of the flux density of sputtered iron using laser induced fluorescence

    International Nuclear Information System (INIS)

    Schweer, H.B.

    1983-11-01

    In this work investigations are described to measure the flux density of sputtered iron atoms by means of laser induced fluorescence. In a laboratory experiment an iron target (stainless steel 316, Inconel 600), was bombarded with 10 keV Ar + and 2.5 keV H + and the population distribution of the energy levels of the ground state a 5 D and the metastable state a 5 F was measured. In the plasma wall region in the ISX-B tokamak at the Oak Ridge National Laboratory (USA) neutral iron atoms were measured the first time by laser induced fluorescence. A detection limit of 10 6 atoms/cm 3 was found and sputtered iron atoms were observed in the first 15 ms of the discharge. (orig./BRB)

  15. Atomic Energy Authority Bill

    International Nuclear Information System (INIS)

    Gray, J.H.N.; Stoddart, D.L.; Sinclair, R.M.; Ezra, D.

    1985-01-01

    The House, in Committee, discussed the following matters in relation to the Atomic Energy Authority Bill; financing; trading; personnel conditions of employment; public relations; organization; research programmes; fuels; energy sources; information dissemination. (U.K.)

  16. Atomic and Molecular Interactions

    International Nuclear Information System (INIS)

    2002-01-01

    The Gordon Research Conference (GRC) on Atomic and 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

  17. Zeeman atomic absorption spectrometry

    International Nuclear Information System (INIS)

    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

  18. Optics With Cold Atoms

    National Research Council Canada - National Science Library

    Hau, Lene

    2004-01-01

    .... And to test the novel atom sensor, we have built a moving-molasses magneto-optical trap in a geometry tailor-suited to the nanotube detector geometry, involving construction of a highly stable laser...

  19. Atomic Energy Control Regulations

    International Nuclear Information System (INIS)

    1992-01-01

    This is the consolidated text of the Atomic Energy Control Regulations of 17 March 1960, with amendments to 27 August 1992. The Regulations cover the licensing of nuclear facilities, radiation sources, including uranium mining, radiation protection questions, etc. (NEA)

  20. The atomic conflict

    International Nuclear Information System (INIS)

    Mez, L.

    1981-01-01

    This book provides a general view at the atomic programmes of several countries and makes an attempt to unmask the atomic industrial combines with their interlockings. The governments role is analysed as well as the atomic policy of the parties, union-trades and associations. Then, the anti-atomic movements in those countries, their forms of resistance, the resonance and the alternative proposals are presented. The countries concerned are Australia, the FRG, COMECON, Danmark, the EG, Finland, France, Great Britain, Ireland, Japan, the Netherlands, Norway, Austria, Sweden, Switzerland, Spain and the USA. For the pocket book version, Lutz Mez adds an updating epilogue which continues with the developments until springtime 1981. (orig./HP) [de

  1. 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.

  2. 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

  3. Atoms at work

    International Nuclear Information System (INIS)

    1982-07-01

    This illustrated booklet discusses the following: atoms; fission of uranium; nuclear power plants; reactor types; plutonium (formation, properties, uses); radioactive waste (fuel cycle, reprocessing, waste management); nuclear fusion; fusion reactors; radiation; radioisotopes and their uses. (U.K.)

  4. 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...

  5. Atomic Interferometry, Phase I

    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...

  6. Atomic bomb cataracts

    International Nuclear Information System (INIS)

    Shiraeda, Kanji

    1992-01-01

    Eye disturbance caused by atomic bomb radiation can be divided into three groups: direct injury immediately after exposure, eye lesions associated with radiation syndrome, and delayed disturbance. The crystalline lens of the eye is the most radiosensitive. Atomic bomb cataract has been investigated in a number of studies. The first section of this chapter discusses radiation cataract in terms of the incidence and characteristics. The second section deals with atomic bomb cataract, which can be diagnosed based on the four criteria: (1) opacity of the crystalline lens, (2) a history of proximal exposure, (3) lack of eye disease complicating cataract, and (4) non-exposure to radiation other than atomic bombing. The prevalence of cataract and severity of opacity are found to correlate with exposure doses and age at the time of exposure. Furthermore, it is found to correlate with distance from the hypocenter, the condition of shielding, epilation, and the presence or absence or degree of radiation syndrome. (N.K.)

  7. The Atomic Energy Control Board

    International Nuclear Information System (INIS)

    Doern, G.B.

    1976-01-01

    This study describes and assesses the regulatory and administrative processes and procedures of the Atomic Energy Control Board, the AECB. The Atomic Energy Control Act authorized the AECB to control atomic energy materials and equipment in the national interest and to participate in measures for the international control of atomic energy. The AECB is authorized to make regulations to control atomic energy materials and equipment and to make grants in support of atomic energy research. (author)

  8. Energy flux of hot atoms

    International Nuclear Information System (INIS)

    Wotzak, G.P.; Kostin, M.D.

    1976-01-01

    The process in which hot atoms collide with thermal atoms of a gas, transfer kinetic energy to them, and produce additional hot atoms is investigated. A stochastic method is used to obtain numerical results for the spatial and time dependent energy flux of hot atoms in a gas. The results indicate that in hot atom systems a front followed by an intense energy flux of hot atoms may develop

  9. Harnessing the atom

    International Nuclear Information System (INIS)

    1999-01-01

    Splitting the atom has had a major impact on the history of the latter part of the 20th century. This film depicts the many benefits - and also drawbacks - of nuclear technology, and describes how the International Atomic Energy Agency performs its various tasks. It touches on challenges such as the choice between major energy sources, growing concerns about the global climate, and prospects for nuclear arms control and disarmament

  10. Atomic Energy Act 1946

    International Nuclear Information System (INIS)

    1946-01-01

    This Act provides for the development of atomic energy in the United Kingdom and for its control. It details the duties and powers of the competent Minister, in particular his powers to obtain information on and to inspect materials, plant and processes, to control production and use of atomic energy and publication of information thereon. Also specified is the power to search for and work minerals and to acquire property. (NEA) [fr

  11. 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.

  12. Manipulating atoms with photons

    International Nuclear Information System (INIS)

    Cohen-Tannoudji, C.N.

    1998-01-01

    The article is a translation of the lecture delivered on the occasion of the 1997 Nobel Prize awarding ceremony. The physical mechanisms which allow manipulating of neutral atoms with laser photons are described. A remark is also made concerning several possible applications of ultra-cool atoms and streams of future research. The article is completed by Prof. Cohen-Tannoudji's autobiography. (Z.J.)

  13. 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.

  14. Fluorescing macerals from wood precursors

    Energy Technology Data Exchange (ETDEWEB)

    Stout, S A; Bensley, D F

    1987-01-01

    A preliminary investigation into the origin of wood-derived macerals has established the existence of autofluorescent maceral precursors in the secondary xylem of swamp-inhabiting plant species. The optical character and fluorescent properties of microtomed thin-sections of modern woods from the Florida Everglades and Okefenokee Swamp, Georgia are compared to the character and properties of their peatified equivalents from various Everglades and Okefenokee peat horizons and their lignitic equivalents from the Brandon lignite of Vermont and the Trail Ridge lignitic peat from northern Florida. The inherent fluorescence of woody cell walls is believed to be caused by lignin though other cell wall components may contribute. The fluorescence spectra for several wood and cell types had a ..gamma../sub m//sub a//sub x/ of 452 nm and Q value of 0.00. The color as observed in blue light and the spectral geometry as measured in UV light of peatified and lignitic woody cell walls (potential textinites) may change progressively during early coalification. Cell wall-derived maceral material is shown to maintain its fluorescing properties after being converted to a structureless material, perhaps a corpohuminite or humodetrinite precursor. Fluorescing xylem cell contents, such as condensed tannins or essential oils, can maintain the fluorescent character through early coalification. Xylem cell walls and xylem cell contents are shown to provide fluorescing progenitor materials which would not require subsequent infusion with 'lipid' materials to account for their fluorescence as phytoclast material or as macerals in coal. 35 references.

  15. 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…

  16. Disruption of the hydrogen bonding network determines the pH-induced non-fluorescent state of the fluorescent protein ZsYellow by protonation of Glu221.

    Science.gov (United States)

    Bae, Ji-Eun; Kim, In Jung; Nam, Ki Hyun

    2017-11-04

    Many fluorescent proteins (FPs) exhibit fluorescence quenching at a low pH. This pH-induced non-fluorescent state of an FP serves as a useful indicator of the cellular pH. ZsYellow is widely used as an optical marker in molecular biology, but its pH-induced non-fluorescent state has not been characterized. Here, we report the pH-dependent spectral properties of ZsYellow, which exhibited the pH-induced non-fluorescence state at a pH below 4.0. We determined the crystal structures of ZsYellow at pH 3.5 (non-fluorescence state) and 8.0 (fluorescence state), which revealed the cis-configuration of the chromophore without pH-induced isomerization. In the non-fluorescence state, Arg95, which is involved in stabilization of the exited state of the chromophore, was found to more loosely interact with the carbonyl oxygen atom of the chromophore when compared to the interaction at pH 8.0. In the fluorescence state, Glu221, which is involved in the hydrogen bonding network around the chromophore, stably interacted with Gln42 and His202. By contrast, in the non-fluorescence state, the protonated conserved Glu221 residue exhibited a large conformational change and was separated from His202 by 5.46 Å, resulting in breakdown of the hydrogen bond network. Our results provide insight into the critical role of the conserved Glu221 residue for generating the pH-induced non-fluorescent state. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Atomic bomb and leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Ichimaru, M; Tomonaga, M; Amenomori, T; Matsuo, T [Nagasaki Univ. (Japan). School of Medicine

    1991-12-01

    Characteristic features of the leukemia among atomic bomb survivors were studied. Dose estimates of atomic bomb radiation were based on T65D, but the new dosimetry system DS86 was used for some analyses. The ratio of a single leukemia type to all leukemias was highest for chronic myelogenous leukemia (CML) in Hiroshima, and the occurrence of CML was thought to be most characteristic to atomic bomb radiation induced leukemia. The threshold of CML occurrence in Hiroshima is likely to be between 0.5{approx}0.09 Gy. However, the threshold of acute leukemia appears to be nearly 1 Gy. In the distribution of acute myeloid leukemia (AML) subtypes by French-American-British classification, there was no M3 case in 1 Gy or more group, although several atypical AML cases of survivors were observed. Although aplastic anemia has not increased as a late effect of the atomic bomb radiation exposure, many atypical leukemia or other myeloproliferative diseases who had been diagnosed as aplastic anemia or its related diseases have been experienced among atomic bomb survivors. Chromosome study was conducted using colony forming cells induced by hemopoietic stem cells of peripheral blood of proximal survivors. Same chromosome aberrations were observed in colony forming cells and peripheral T-cells in several atomic bomb survivors. (author).

  18. On the bosonic atoms

    Science.gov (United States)

    Amusia, M. Ya.; Chernysheva, L. V.

    2018-01-01

    We investigate ground state properties of atoms, in which substitute fermions - electrons by bosons, namely π --mesons. We perform some calculations in the frame of modified Hartree-Fock (HF) equation. The modification takes into account symmetry, instead of anti-symmetry of the pair identical bosons wave function. The modified HF approach thus enhances (doubles) the effect of self-action for the boson case. Therefore, we accordingly modify the HF equations by eliminating the self-action terms "by hand". The contribution of meson-meson and meson-nucleon non-Coulomb interaction is inessential at least for atoms with low and intermediate nuclear charge, which is our main subject. We found that the binding energy of pion negative ions A π - , pion atoms A π , and the number of extra bound pions ΔN π increases with the growth of nuclear charge Z. For e.g. Xe ΔN π = 4. As an example of a simple process with a pion atom, we consider photoionization that differs essentially from that for electron atoms. Namely, it is not monotonic decreasing from the threshold but has instead a prominent maximum above threshold. We study also elastic scattering of pions by pion atoms.

  19. Electron - atom bremsstrahlung

    International Nuclear Information System (INIS)

    Kim, L.

    1986-01-01

    Features of bremsstrahlung radiation from neutral atoms and atoms in hot dense plasmas are studied. Predictions for the distributions of electron-atom bremsstrahlung radiation for both the point-Coulomb potential and screened potentials are obtained using a classical numerical method. Results agree with exact quantum-mechanical partial-wave results for low incident electron energies in both the point-Coulomb and screened potentials. In the screened potential, the asymmetry parameter of a spectrum is reduced from the Coulomb values. The difference increases with decreasing energy and begins to oscillate at very low energies. The scaling properties of bremsstrahlung spectra and energy losses were also studied. It was found that the ratio of the radiative energy loss for positrons to that for electrons obeys a simple scaling law, being expressible fairly accurately as a function only of the quantity T 1 /Z 2 . This scaling is exact in the case of the point-Coulomb potential, both for classical bremsstrahlung and for the nonrelativistic dipole Sommerfeld formula. Bremsstrahlung from atoms in hot dense plasmas were also studied describing the atomic potentials by the temperature-and-density dependent Thomas-Fermi mode. Gaunt factors were obtained with the relativistic partial-wave method for atoms in plasmas of various densities and temperatures

  20. FAO and atomic energy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1960-07-15

    During the past six years FAO has become more engaged in work concerned with atomic energy. In 1957 it established an Atomic Energy Branch. The new forces and new tools which have become available for use in the fight against poverty, disease and malnutrition can be of the greatest assistance in FAO's work in nearly all phases of the production, storage and distribution of food and other agricultural products. The Organization promotes their use to improve the standards of feeding, clothing and housing throughout the world. Another side of work related to atomic energy is concerned with combating contamination from the use of atomic energy for power production and other purposes. This raises considerable problems for food and agriculture, so that FAO also has a responsibility for assisting Governments in safeguarding their food and food-producing resources from contamination. FAO is essentially concerned with fostering wider knowledge of the many contributions that atomic science can make to agriculture, forestry, fisheries and nutrition. It is also concerned in assisting governments to establish sound programmes for applying atomic science in food and agriculture. One way of spreading such knowledge is through the publication of documents and reports

  1. Atomic clocks for geodesy

    Science.gov (United States)

    Mehlstäubler, Tanja E.; Grosche, Gesine; Lisdat, Christian; Schmidt, Piet O.; Denker, Heiner

    2018-06-01

    We review experimental progress on optical atomic clocks and frequency transfer, and consider the prospects of using these technologies for geodetic measurements. Today, optical atomic frequency standards have reached relative frequency inaccuracies below 10‑17, opening new fields of fundamental and applied research. The dependence of atomic frequencies on the gravitational potential makes atomic clocks ideal candidates for the search for deviations in the predictions of Einstein’s general relativity, tests of modern unifying theories and the development of new gravity field sensors. In this review, we introduce the concepts of optical atomic clocks and present the status of international clock development and comparison. Besides further improvement in stability and accuracy of today’s best clocks, a large effort is put into increasing the reliability and technological readiness for applications outside of specialized laboratories with compact, portable devices. With relative frequency uncertainties of 10‑18, comparisons of optical frequency standards are foreseen to contribute together with satellite and terrestrial data to the precise determination of fundamental height reference systems in geodesy with a resolution at the cm-level. The long-term stability of atomic standards will deliver excellent long-term height references for geodetic measurements and for the modelling and understanding of our Earth.

  2. FAO and atomic energy

    International Nuclear Information System (INIS)

    1960-01-01

    During the past six years FAO has become more engaged in work concerned with atomic energy. In 1957 it established an Atomic Energy Branch. The new forces and new tools which have become available for use in the fight against poverty, disease and malnutrition can be of the greatest assistance in FAO's work in nearly all phases of the production, storage and distribution of food and other agricultural products. The Organization promotes their use to improve the standards of feeding, clothing and housing throughout the world. Another side of work related to atomic energy is concerned with combating contamination from the use of atomic energy for power production and other purposes. This raises considerable problems for food and agriculture, so that FAO also has a responsibility for assisting Governments in safeguarding their food and food-producing resources from contamination. FAO is essentially concerned with fostering wider knowledge of the many contributions that atomic science can make to agriculture, forestry, fisheries and nutrition. It is also concerned in assisting governments to establish sound programmes for applying atomic science in food and agriculture. One way of spreading such knowledge is through the publication of documents and reports

  3. Atomic bomb and leukemia

    International Nuclear Information System (INIS)

    Ichimaru, M.; Tomonaga, M.; Amenomori, T.; Matsuo, T.

    1991-01-01

    Characteristic features of the leukemia among atomic bomb survivors were studied. Dose estimates of atomic bomb radiation were based on T65D, but the new dosimetry system DS86 was used for some analyses. The ratio of a single leukemia type to all leukemias was highest for chronic myelogenous leukemia (CML) in Hiroshima, and the occurrence of CML was thought to be most characteristic to atomic bomb radiation induced leukemia. The threshold of CML occurrence in Hiroshima is likely to be between 0.5∼0.09 Gy. However, the threshold of acute leukemia appears to be nearly 1 Gy. In the distribution of acute myeloid leukemia (AML) subtypes by French-American-British classification, there was no M3 case in 1 Gy or more group, although several atypical AML cases of survivors were observed. Although aplastic anemia has not increased as a late effect of the atomic bomb radiation exposure, many atypical leukemia or other myeloproliferative diseases who had been diagnosed as aplastic anemia or its related diseases have been experienced among atomic bomb survivors. Chromosome study was conducted using colony forming cells induced by hemopoietic stem cells of peripheral blood of proximal survivors. Same chromosome aberrations were observed in colony forming cells and peripheral T-cells in several atomic bomb survivors. (author)

  4. Atomic phenomena in dense plasmas

    International Nuclear Information System (INIS)

    Weisheit, J.C.

    1981-03-01

    The following chapters are included: (1) the plasma environment, (2) perturbations of atomic structure, (3) perturbations of atomic collisions, (4) formation of spectral lines, and (5) dielectronic recombination

  5. Time-resolved fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gustavsson, Thomas; Mialocq, Jean-Claude

    2007-01-01

    This article addresses the evolution in time of light emitted by a molecular system after a brief photo-excitation. The authors first describe fluorescence from a photo-physical point of view and discuss the characterization of the excited state. Then, they explain some basic notions related to fluorescence characterization (lifetime and decays, quantum efficiency, so on). They present the different experimental methods and techniques currently used to study time-resolved fluorescence. They discuss basic notions of time resolution and spectral reconstruction. They briefly present some conventional methods: intensified Ccd cameras, photo-multipliers and photodiodes associated with a fast oscilloscope, and phase modulation. Other methods and techniques are more precisely presented: time-correlated single photon counting (principle, examples, and fluorescence lifetime imagery), streak camera (principle, examples), and optical methods like the Kerr optical effect (principle and examples) and fluorescence up-conversion (principle and theoretical considerations, examples of application)

  6. Laser Cooling without Repumping: A Magneto-Optical Trap for Erbium Atoms

    International Nuclear Information System (INIS)

    McClelland, J.J.; Hanssen, J.L.

    2006-01-01

    We report on a novel mechanism that allows for strong laser cooling of atoms that do not have a closed cycling transition. This mechanism is observed in a magneto-optical trap (MOT) for erbium, an atom with a very complex energy level structure with multiple pathways for optical-pumping losses. We observe surprisingly high trap populations of over 10 6 atoms and densities of over 10 11 atoms cm -3 , despite the many potential loss channels. A model based on recycling of metastable and ground state atoms held in the quadrupole magnetic field of the trap explains the high trap population, and agrees well with time-dependent measurements of MOT fluorescence. The demonstration of trapping of a rare-earth atom such as erbium opens a wide range of new possibilities for practical applications and fundamental studies with cold atoms

  7. Photon-number statistics in resonance fluorescence

    Science.gov (United States)

    Lenstra, D.

    1982-12-01

    The theory of photon-number statistics in resonance fluorescence is treated, starting with the general formula for the emission probability of n photons during a given time interval T. The results fully confirm formerly obtained results by Cook that were based on the theory of atomic motion in a traveling wave. General expressions for the factorial moments are derived and explicit results for the mean and the variance are given. It is explicitly shown that the distribution function tends to a Gaussian when T becomes much larger than the natural lifetime of the excited atom. The speed of convergence towards the Gaussian is found to be typically slow, that is, the third normalized central moment (or the skewness) is proportional to T-12. However, numerical results illustrate that the overall features of the distribution function are already well represented by a Gaussian when T is larger than a few natural lifetimes only, at least if the intensity of the exciting field is not too small and its detuning is not too large.

  8. 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

  9. Fluorescent multiplex cell flow systems and methods

    KAUST Repository

    Merzaban, Jasmeen; Abuelela, Ayman F.; Mohammad, Amal Jehad

    2017-01-01

    scanning system emits multiple electromagnetic wavelengths simultaneously it cause multiple fluorescent labels having different excitation wavelength maximums to fluoresce. The system can simultaneously capture real-time fluorescence images from at least

  10. Nuclear-driven flashlamp pumping of the atomic iodine laser

    International Nuclear Information System (INIS)

    Miley, G.H.

    1992-03-01

    This report is a study of the atomic iodine laser pumped with nuclear- excited XeBr fluorescence. Preliminary experiments, conducted in the TRIGA reactor investigated the fluorescence of the excimer XeBr under nuclear pumping with 10 B and 3 He, for use as a flashlamp gas to stimulate the laser. These measurements included a determination of the fluorescence efficiency (light emitted in the wavelength region of interest, divided by energy deposited in the gas) of XeBr under nuclear pumping, with varying excimer mixtures. Maximum fluorescence efficiencies were approximately 1%. In order to better understand XeBr under nuclear excitation, a kinetics model of the system was prepared. The model generated the time-dependant concentrations of 20 reaction species for three pulse sizes, a TRIGA pulse, a fast burst reactor pulse, and an e-beam pulse. The modeling results predicted fluorescence efficiencies significantly higher (peak efficiencies of approximately 10%) than recorded in the fluorescence experiments. The cause of this discrepancy was not fully determined. A ray tracing computer model was also prepared to evaluate the efficiency with which nuclear-induced fluorescence generated in one cavity of a laser could be coupled into another cavity containing an iodine lasant. Finally, an experimental laser cell was constructed to verify that nuclear-induced XeBr fluorescence could be used to stimulate a laser. Lasing was achieved at 1.31 micron in the TRIGA using C 3 F 7 I, a common iodine lasant. Peak laser powers were approximately 20 mW. Measured flashlamp pump powers at threshold agreed well with literature values, as did lasant pressure dependency on laser operation

  11. 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)

  12. Fluorescent standards for photodynamic therapy

    Science.gov (United States)

    Belko, N.; Kavalenka, S.; Samtsov, M.

    2016-08-01

    Photodynamic therapy is an evolving technique for treatment of various oncological diseases. This method employs photosensitizers - species that lead to death of tumor cells after the photoactivation. For further development and novel applications of photodynamic therapy new photosensitizers are required. After synthesis of a new photosensitizer it is important to know its concentration in different biological tissues after its administration and distribution. The concentration is frequently measured by the extraction method, which has some disadvantages, e.g. it requires many biological test subjects that are euthanized during the measurement. We propose to measure the photosensitizer concentration in tissue by its fluorescence. For this purpose fluorescent standards were developed. The standards are robust and simple to produce; their fluorescence signal does not change with time. The fluorescence intensity of fluorescent standards seems to depend linearly on the dye concentration. A set of standards thus allow the calibration of a spectrometer. Finally, the photosensitizer concentration can be determined by the fluorescence intensity after comparing the corresponding spectrum with spectra of the set of fluorescent standards. A biological test subject is not euthanized during this kind of experiment. We hope this more humane technique can be used in future instead of the extraction method.

  13. UNESCO and atomic energy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1960-01-15

    Atomic energy has been of particular concern to UNESCO virtually since the founding of this United Nations agency with the mission of promoting the advancement of science along with education and culture. UNESCO has been involved in the scientific aspects of nuclear physics - notably prior to the creation of the International Atomic Energy Agency - but it has also focussed its attention upon the educational and cultural problems of the atomic age. UNESCO's sphere of action was laid down by its 1954 General Conference which authorized its Director-General to extend full co-operation to the United Nations in atomic energy matters, with special reference to 'the urgent study of technical questions such as those involved in the effects of radioactivity on life in general, and to the dissemination of objective information concerning all aspects of the peaceful utilization of atomic energy; to study, and if necessary, to propose measures of international scope to facilitate the use of radioisotopes in research and industry'. UNESCO's first action under this resolution was to call a meeting of a committee of experts from twelve nations to study the establishment of a system of standards and regulations for the preparation, distribution, transport and utilization of radioactive isotopes and tracer molecules

  14. High-speed atomic force microscopy combined with inverted optical microscopy for studying cellular events.

    OpenAIRE

    Suzuki, Yuki; Sakai, Nobuaki; Yoshida, Aiko; Uekusa, Yoshitsugu; Yagi, Akira; Imaoka, Yuka; Ito, Shuichi; Karaki, Koichi; Takeyasu, Kunio

    2013-01-01

    A hybrid atomic force microscopy (AFM)-optical fluorescence microscopy is a powerful tool for investigating cellular morphologies and events. However, the slow data acquisition rates of the conventional AFM unit of the hybrid system limit the visualization of structural changes during cellular events. Therefore, high-speed AFM units equipped with an optical/fluorescence detection device have been a long-standing wish. Here we describe the implementation of high-speed AFM coupled with an optic...

  15. Fluorescence molecular tomography in the presence of background fluorescence

    International Nuclear Information System (INIS)

    Soubret, Antoine; Ntziachristos, Vasilis

    2006-01-01

    Fluorescence molecular tomography is an emerging imaging technique that resolves the bio-distribution of engineered fluorescent probes developed for in vivo reporting of specific cellular and sub-cellular targets. The method can detect fluorochromes in picomole amounts or less, imaged through entire animals, but the detection sensitivity and imaging performance drop in the presence of background, non-specific fluorescence. In this study, we carried out a theoretical and an experimental investigation on the effect of background fluorescence on the measured signal and on the tomographic reconstruction. We further examined the performance of three subtraction methods based on physical models of photon propagation, using experimental data on phantoms and small animals. We show that the data pre-processing with subtraction schemes can improve image quality and quantification when non-specific background florescence is present

  16. Accelerators for atomic energy research

    International Nuclear Information System (INIS)

    Shibata, Tokushi

    1999-01-01

    The research and educational activities accomplished using accelerators for atomic energy research were studied. The studied items are research subjects, facility operation, the number of master theses and doctor theses on atomic energy research using accelerators and the future role of accelerators in atomic energy research. The strategy for promotion of the accelerator facility for atomic energy research is discussed. (author)

  17. Atomic nucleus and elementary particles

    International Nuclear Information System (INIS)

    Zakrzewski, J.

    1976-01-01

    Negatively charged leptons and hadrons can be incorporated into atomic shells forming exotic atoms. Nucleon resonances and Λ hyperons can be considered as constituents of atomic nuclei. Information derived from studies of such exotic systems enriches our knowledge of both the interactions of elementary particles and of the structure of atomic nuclei. (author)

  18. Impurity studies in fusion devices using laser-fluorescence-spectroscopy

    International Nuclear Information System (INIS)

    Husinsky, W.R.

    1980-08-01

    Resonance fluorescence excitation of neutral atoms using tunable radiation from dye lasers offers a number of unique advantages for impurity studies in fusion devices. Using this technique, it is possible to perform local, time-resolved measurements of the densities and velocity distributions of metallic impurities in fusion devices without disturbing the plasma. Velocities are measured by monitoring the fluorescence intensity while tuning narrow bandwidth laser radiation through the Doppler - broadened absorbtion spectrum of the transition. The knowledge of the velocity distribution of neutral impurities is particularly useful for the determination of impurity introduction mechanisms. The laser fluorescence technique will be described in terms of its application to metallic impurities in fusion devices and related laboratory experiments. Particular attention will be given to recent results from the ISX-B tokamak using pulsed dye lasers where detection sensitivities for neutral Fe of 10 6 atoms/cm 3 with a velocity resolution of 600 m/sec (0.1 eV) have been achieved. Techniques for exciting plasma particles (H,D) will also be discussed

  19. Single atoms on demand for cavity QED experiments

    International Nuclear Information System (INIS)

    Dotsenko, I.

    2007-01-01

    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 cavity

  20. 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

  1. Compilation of data from hadronic atoms

    International Nuclear Information System (INIS)

    Poth, H.

    1979-01-01

    This compilation is a survey of the existing data of hadronic atoms (pionic-atoms, kaonic-atoms, antiprotonic-atoms, sigmonic-atoms). It collects measurements of the energies, intensities and line width of X-rays from hadronic atoms. Averaged values for each hadronic atom are given and the data are summarized. The listing contains data on 58 pionic-atoms, on 54 kaonic-atoms, on 23 antiprotonic-atoms and on 20 sigmonic-atoms. (orig./HB) [de

  2. CP violation in atoms

    International Nuclear Information System (INIS)

    Barr, S.M.

    1992-01-01

    Electric dipole moments of large atoms are an excellent tool to search for CP violation beyond the Standard Model. These tell us about the electron EDM but also about CP-violating electron-nucleon dimension-6 operators that arise from Higgs-exchange. Rapid strides are being made in searches for atomic EDMs. Limits on the electron EDM approaching the values which would be expected from Higgs-exchange mediated CP violation have been achieved. It is pointed out that in this same kind of model if tan β is large the effects in atoms of the dimension-6 e - n operators may outweigh the effect of the electron EDM. (author) 21 refs

  3. US Atomic Energy Law

    International Nuclear Information System (INIS)

    1981-01-01

    This is a new volume follows in the series supplementing the volumes 11 and 12 published in 1965 and 1966, updating the collection of Federal Acts and Executive Orders of the President of the United States of America relating to atomic energy legislation. Since the publication of volumes 11 and 12, the US Atomic Energy Act of 1954 alone has been amended 25 times, mainly as a consequence of by the Nuclear Non-Proliferation Act and the Uranium Mill Tailings Radiation Control Act, both of 1978. The Atomic Energy Act of 1954 is supplemented by a selection of the most important Federal Acts, Executive Orders of the President and Resolutions of the Congress. (orig./HSCH) [de

  4. Atomic profits, no thanks

    International Nuclear Information System (INIS)

    Bartels, W.; Dietrich, K.; Moeller, H.; Speier, C.

    1980-01-01

    The authors deal with the following topics: The secret of nuclear energy; the atom programmes of Bonn; on some arguments of the present nuclear energy discussion; how socialist countries solve the problems of nuclear energy. From the socialist point of view they discuss sociological, ideological and moral reasons for a peaceful utilization of nuclear energy. Nevertheless they refuse Bonn's atom programme because the high finance's interests concerning profit and power make it a danger. The biggest danger is said to lie in the creation of a plutonium-industry and the militaristic abuse which would be connected with it. The socialist way of utilizing atomic energy is seen by them as a way with a high feeling of responsibility towards all people and towards a guaranteed energy supply. (HSCH) [de

  5. Controlling the atom

    International Nuclear Information System (INIS)

    Mazuzan, G.T.; Walker, J.S.

    1984-01-01

    The authors trace the early history of nuclear power regulation in the US. Focusing on the Atomic Energy Commission, they describe the role of other groups that figured in the development of regulatory policies, including the Congressional Joint Committee on Atomic Energy, other federal agencies, state governments, the nuclear industry, and scientific organizations. They consider changes in public perceptions of and attitudes toward atomic energy and the dangers of radiation exposure. The basic purpose of the book is to provide the Nuclear Regulatory Commission and the general public with information on the historical antecedents and background of regulatory issues so that there will be continuity in policy decisions. The book concludes with an annotated bibliography of selected references. 19 figures

  6. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.

    1985-01-01

    Experimental and theoretical achievements in studying Rydberg atoms in external fields are considered. Only static (or quasistatic) fields and ''one-electron'' atoms, i.e. atoms that are well described by one-electron states, are discussed. Mainly behaviour of alkali metal atoms in electric field is considered. The state of theoretical investigations for hydrogen atom in magnetic field is described, but experimental data for atoms of alkali metals are presented as an illustration. Results of the latest experimental and theoretical investigations into the structure of Rydberg atoms in strong fields are presented

  7. Atoms in Slovakia

    International Nuclear Information System (INIS)

    Danis, D.; Feik, K.; Florek, M.; Kmosena, J.; Chrapan, J.; Morovic, M.; Slugen, V.; Seliga, M.; Valovic, J.

    2006-01-01

    In this book the history of development of using of nuclear energy in the Slovak Republic as well as in the Czechoslovakia (before 1993 year) is presented. The aim of the book is to preserve the memory of the period when the creation and development of nuclear physics, technology, nuclear medicine, radioecology and energetics in Slovakia occurred - as witnessed by people who experienced this period and to adapt it to future generations. The Editorial board of the SNUS collected the views of 60 contributors and distinguished workers - Slovakian experts in nuclear science, education and technology. Calling upon a wide spectrum of experts ensured an objective historical description of the period. A huge amount of subjective views on recent decades were collected and supported by a wealth of photographic documentation. This created a synthesised reflection on the history of the 'atoms' in Slovakia. The book contains 15 tables, 192 black and white and 119 colour pictures from around the world and from places involved in the compilation of the study and with the study of atomic science in Slovakia. The main chapters are as follows: Atoms in the world, Atoms in Slovakia, Atoms in the educational system, Atoms in health services (Radiology, Nuclear medicine, Radiation protection, the Cyclotron centre of the Slovak Republic), Radioecology, Other applications of irradiation, Nuclear energetics (Electric energy in the second half of the 20 th century, NPP Bohunice, NPP Mochovce, the back-end of Nuclear energetics, Big names in Nuclear energetics in Slovakia), Chronology and an Appendix entitled 'Slovak companies in nuclear energetics'

  8. Positron-atom collisions

    International Nuclear Information System (INIS)

    Drachman, R.J.

    1984-01-01

    The past decade has seen the field of positron-atom collisions mature into an important sub-field of atomic physics. Increasingly intense positron sources are leading towards a situation in which electron and positron collision experiments will be on almost an equal footing, challenging theory to analyze their similarities and differences. The author reviews the advances made in theory, including dispersion theory, resonances, and inelastic processes. A survey of experimental progress and a brief discussion of astrophysical positronics is also included. (Auth.)

  9. 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.

  10. 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

  11. Atomic cluster collisions

    Science.gov (United States)

    Korol, Andrey V.; Solov'yov, Andrey

    2013-01-01

    Atomic cluster collisions are a field of rapidly emerging research interest by both experimentalists and theorists. The international symposium on atomic cluster collisions (ISSAC) is the premier forum to present cutting-edge research in this field. It was established in 2003 and the most recent conference was held in Berlin, Germany in July of 2011. This Topical Issue presents original research results from some of the participants, who attended this conference. This issues specifically focuses on two research areas, namely Clusters and Fullerenes in External Fields and Nanoscale Insights in Radiation Biodamage.

  12. Pulsed atomic soliton laser

    International Nuclear Information System (INIS)

    Carr, L.D.; Brand, J.

    2004-01-01

    It is shown that simultaneously changing the scattering length of an elongated, harmonically trapped Bose-Einstein condensate from positive to negative and inverting the axial portion of the trap, so that it becomes expulsive, results in a train of self-coherent solitonic pulses. Each pulse is itself a nondispersive attractive Bose-Einstein condensate that rapidly self-cools. The axial trap functions as a waveguide. The solitons can be made robustly stable with the right choice of trap geometry, number of atoms, and interaction strength. Theoretical and numerical evidence suggests that such a pulsed atomic soliton laser can be made in present experiments

  13. Polarized atomic beams for targets

    International Nuclear Information System (INIS)

    Grueebler, W.

    1984-01-01

    The basic principle of the production of polarized atomic hydrogen and deuterium beams are reviewed. The status of the present available polarization, density and intensity are presented. The improvement of atomic beam density by cooling the hydrogen atoms to low velocity is discussed. The possible use of polarized atomic beams as targets in storage rings is shown. It is proposed that polarized atomic beams can be used to produce polarized gas targets with high polarization and greatly improved density

  14. Mercury depletion as a way of changing the emission spectrum of a fluorescent lamp

    NARCIS (Netherlands)

    Bakker, L.P.; Kroesen, G.M.W.

    2000-01-01

    We present a promising option for changing the emission spectrum of a fluorescent lamp. In a neon/mercury discharge, neon radiation is produced when the mercury density is sufficiently low. Under certain discharge conditions, radial cathaphoresis causes depletion of mercury atoms in the center of

  15. Study of the interaction of Tb (III) with dextran through fluorescence spectroscopy and optical rotatory dispersion

    International Nuclear Information System (INIS)

    Vasconcelos, Sandra S.; Rodrigues, J.F.

    1984-01-01

    A study of the interaction of Tb(III) with dextran in aqueous solution was perform using fluorescence spectroscopy and optical rotatory dispersion. The results indicate the formation of a complex with the displacent of water from the cation coordinated sphere by hydroxyl groups at the second and third carbon atoms of the monomer unit. (Author) [pt

  16. Instructive for disposal of fluorescent

    International Nuclear Information System (INIS)

    Salazar Vargas, Gerlin

    2014-01-01

    An instructive is established for the management system of waste fluorescent lamps, ensuring the storage, collection, transportation, and final disposal. The lamp is changed by an official of the Seccion de Matenimiento Construccion of the Oficina de Servicios Generales or is produced with the support of an official of the unit. The fluorescent should be deposited in stock of materials of the building maintenance section or unit specified with the help of a staff and in appropriate conditions. The fluorescent lamp is transported according to the guidelines in the manual. A responsible company is contracted by la Vicerrectoria de Administracion of the Universidad de Costa Rica dedicated to the transport and proper handling of fluorescent lamps [es

  17. ANTAGONISTIC POTENTIAL OF FLUORESCENT Pseudomonas ...

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    GROWTH OF TOMATO CHALLENGED WITH PHTOPATHOGENS ... This study focused on the antagonistic potential of fluorescent Pseudomonas in vitro, and its inoculation effect on growth .... the 5 days old culture in starch agar with Lugol's.

  18. Atomic collisions related to atomic laser isotope separation

    International Nuclear Information System (INIS)

    Shibata, Takemasa

    1995-01-01

    Atomic collisions are important in various places in atomic vapor laser isotope separation (AVLIS). At a vaporization zone, many atomic collisions due to high density have influence on the atomic beam characteristics such as velocity distribution and metastable states' populations at a separation zone. In the separation zone, a symmetric charge transfer between the produced ions and the neutral atoms may degrade selectivity. We have measured atomic excitation temperatures of atomic beams and symmetric charge transfer cross sections for gadolinium and neodymium. Gadolinium and neodymium are both lanthanides. Nevertheless, results for gadolinium and neodymium are very different. The gadolinium atom has one 5d electron and neodymium atom has no 5d electron. It is considered that the differences are due to existence of 5d electron. (author)

  19. Spatially resolved photoionization of ultracold atoms on an atom chip

    International Nuclear Information System (INIS)

    Kraft, S.; Guenther, A.; Fortagh, J.; Zimmermann, C.

    2007-01-01

    We report on photoionization of ultracold magnetically trapped Rb atoms on an atom chip. The atoms are trapped at 5 μK in a strongly anisotropic trap. Through a hole in the chip with a diameter of 150 μm, two laser beams are focused onto a fraction of the atomic cloud. A first laser beam with a wavelength of 778 nm excites the atoms via a two-photon transition to the 5D level. With a fiber laser at 1080 nm the excited atoms are photoionized. Ionization leads to depletion of the atomic density distribution observed by absorption imaging. The resonant ionization spectrum is reported. The setup used in this experiment is suitable not only to investigate mixtures of Bose-Einstein condensates and ions but also for single-atom detection on an atom chip

  20. Multimodal Sensing Strategy Using pH Dependent Fluorescence Switchable System

    Science.gov (United States)

    Muthurasu, A.; Ganesh, V.

    2016-12-01

    Biomolecules assisted preparation of fluorescent gold nanoparticles (FL-Au NPs) has been reported in this work using glucose oxidase enzyme as both reducing and stabilizing agent and demonstrated their application through multimodal sensing strategy for selective detection of cysteine (Cys). Three different methods namely fluorescence turn OFF-ON strategy, naked eye detection and electrochemical methods are used for Cys detection by employing FL-Au NPs as a common probe. In case of fluorescence turn-OFF method a strong interaction between Au NPs and thiol results in quenching of fluorescence due to replacement of glucose oxidase by Cys at neutral pH. Second mode is based on fluorescence switch-ON strategy where initial fluorescence is significantly quenched by either excess acid or base and further addition of Cys results in appearance of rosy-red and green fluorescence respectively. Visual colour change and fluorescence emission arises due to etching of Au atoms on the surface by thiol leading to formation of Au nanoclusters. Finally, electrochemical sensing of Cys is also carried out using cyclic voltammetry in 0.1 M PBS solution. These findings provide a suitable platform for Cys detection over a wide range of pH and concentration levels and hence the sensitivity can also be tuned accordingly.