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Sample records for generation atomic fluorescence

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

    Science.gov (United States)

    Sun, Han-Wen; Suo, Ran

    2008-11-01

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

  2. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  4. [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.

  5. 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.

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

    Institute of Scientific and Technical Information of China (English)

    LIAO Meng-xia; DENG Tian-long

    2006-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-11-15

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

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

    Science.gov (United States)

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

    2011-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-15

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

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

    Science.gov (United States)

    Liu, Qingyang

    2010-07-01

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

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

    Science.gov (United States)

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

    2001-10-01

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

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

    Science.gov (United States)

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

    2006-11-10

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

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

    Science.gov (United States)

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

    2007-06-01

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

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

    Science.gov (United States)

    Wan, Zhuo; Xu, Zhangrun; Wang, Jianhua

    2006-01-01

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

  15. Arsenic speciation analysis by HPLC postcolumn hydride generation and detection by atomic fluorescence spectrometry

    OpenAIRE

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

    2014-01-01

    The aim of this contribution is to present a new method of hydride generation that enables to generate arsines from iAs , iAs , MMA and DMA in a flow injection mode with the same efficiency and in the next step connection of this hydride generator with HPLC column.

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

    Science.gov (United States)

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

    2014-10-21

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-11-30

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

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2015-09-01

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

  20. 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.

  1. 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.

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

    Science.gov (United States)

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

    2000-08-01

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

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

    Science.gov (United States)

    Tong, Wang; Ying, Zeng; Jinyong, Xu

    2016-09-01

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

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

    Science.gov (United States)

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

    2008-08-01

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

  5. Imaging an atomic beam using fluorescence

    Institute of Scientific and Technical Information of China (English)

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

    2003-01-01

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

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

    Science.gov (United States)

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

    2014-05-21

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

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

    Science.gov (United States)

    Duan, Xuchuan; Sun, Rui; Fang, Jinliang

    2017-02-01

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

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

    OpenAIRE

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2013-10-01

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

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

    Science.gov (United States)

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

    2016-08-01

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

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

    Science.gov (United States)

    Duan, Xuchuan; Zhang, Jingya; Bu, Fanlong

    2015-09-01

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

  13. 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.)

  14. [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

  15. 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.

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

    Science.gov (United States)

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

    2012-03-01

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

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

    Science.gov (United States)

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

    2013-03-15

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

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

    Science.gov (United States)

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

    2016-01-01

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

  19. Containerless Atomic-Fluorescence Property Measurements

    Science.gov (United States)

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

    1987-01-01

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

  20. Modular generation of fluorescent phycobiliproteins.

    Science.gov (United States)

    Wu, Xian-Jun; Chang, Kun; Luo, Juan; Zhou, Ming; Scheer, Hugo; Zhao, Kai-Hong

    2013-06-01

    Phycobiliproteins are brightly-fluorescent light-harvesting pigments for photosynthesis in cyanobacteria and red algae. They are also of interest as fluorescent biomarkers, but their heterologous generation in vivo has previously required multiple transformations. We report here a modular approach that requires only two DNA segments. The first codes for the apo-protein. The second codes for fusions capable of chromophore biosynthesis and its covalent attachment to the apo-protein; it contains the genes of heme oxygenase, a bilin reductase, and a chromophore lyase. Phycobiliproteins containing phycoerythrobilin (λ(fluor) ~ 560 nm), phycourobilin (λ(fluor) ~ 500 nm), phycocyanobilin (λ(fluor) ~ 630 nm) or phycoviolobilin (λ(fluor) ~ 580 nm) were obtained in high yield in E. coli. This approach facilitates chromophorylation studies of phycobiliproteins, as well as their use for fluorescence labeling based on their high fluorescence.

  1. Study on Atomic Fluorescence Spectrometry Excited by Synchrotron Radiation

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

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

    Science.gov (United States)

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

    2015-05-18

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

  3. 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

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

    Science.gov (United States)

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

    2014-11-01

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

  5. 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}.

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

    Institute of Scientific and Technical Information of China (English)

    魏静; 梁琼; 刘俊娓

    2013-01-01

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

  7. Atomic fluorescence study of high temperature aerodynamic levitation

    Science.gov (United States)

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

    1982-01-01

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

  8. Resonance Fluorescence from an Artificial Atom in Squeezed Vacuum

    National Research Council Canada - National Science Library

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

    2016-01-01

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

  9. Containerless high temperature property measurements by atomic fluorescence

    Science.gov (United States)

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

    1982-01-01

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

  10. Theory of analytical curves in atomic fluorescence flame spectrometry

    NARCIS (Netherlands)

    Hooymayers, H.P.

    1968-01-01

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

  11. 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.

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

    Institute of Scientific and Technical Information of China (English)

    杨庆惠

    2012-01-01

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

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

    Science.gov (United States)

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

    2005-10-31

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

  14. Antimony speciation in soils: improving the detection limits using post-column pre-reduction hydride generation atomic fluorescence spectroscopy (HPLC/pre-reduction/HG-AFS).

    Science.gov (United States)

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

    2011-04-15

    HG-AFS is highly sensitive and low cost detection system and its use for antimony chemical speciation coupled to HPLC is gaining popularity. However speciation analysis in soils is strongly hampered because the most efficient extractant reported in the literature (oxalic acid) strongly inhibits the generation of SbH(3) by Sb(V), the major species in this kind of matrix, severely affecting its detection limits. The purpose of this research is to reduce the detection limit of Sb(V), by using a post column on-line reduction system with l-cysteine reagent (HPLC/pre-reduction/HG-AFS). The system was optimized by experimental design, optimum conditions found were 2% (w/v) and 10°C temperature coil. Detection limits of Sb(V) and Sb(III) in oxalic acid (0.25 mol L(-1)) were improved from 0.3 and 0.1 μg L(-1) to 0.07 and 0.07 μg L(-1), respectively. The methodology developed was applied to Chilean soils, where Sb(V) was the predominant species. Copyright © 2011 Elsevier B.V. All rights reserved.

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

    Institute of Scientific and Technical Information of China (English)

    陈殿耿; 袁玉霞; 何飞顶

    2012-01-01

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

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

    Science.gov (United States)

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

    2007-09-01

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

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

    OpenAIRE

    2000-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  19. Cavity Loss Induced Generation of Entangled Atoms

    CERN Document Server

    Plenio, M B; Beige, A; Knight, P L

    1999-01-01

    We discuss the generation of entangled states of two two-level atoms inside an optical resonator. When the cavity decay is continuously monitored, the absence of photon-counts is associated with the presence of an atomic entangled state. In addition to being conceptually simple, this scheme could be demonstrated with presently available technology. We describe how such a state is generated through conditional dynamics, using quantum jump methods, including both cavity damping and spontaneous emission decay, and evaluate the fidelity and relative entropy of entanglement of the generated state compared with the target entangled state.

  20. Generation and Purification of Atomic Entangled States

    Institute of Scientific and Technical Information of China (English)

    YANG Ming; SONG Wei; LI Yingqun; SHI Shouhua; CAO Zhuoliang

    2004-01-01

    @@ Entangled state plays a more and more important role in quantum information, so the generation of entangled state is of scientific value and practical significance.Although the experimental realization of entangled pairs of atoms and polarized photons have been reported recently, the current preparation schemes cannot meet the need of the practical application of entangled state in Quantum Communication and Quantum Computation.At the same time, resulting from the coupling between the quantum systems and its environment, decoherence of the quantum systems is unavoidable, which sets a vital obstacle on the way of the application of entanglement.There exist some entanglement generation and purification schemes, but the range of its application is relative small.So we proposed a more efficient scheme for entanglement generation and purification.The scheme is mainly based on the combination of linear optics and Cavity QED technique.The entanglement generation scheme can entangle two atoms by using MZI plus an optical cavity.Pure maximally entangled atomic states can be generated from product states or mixed states.Using a MZI, we can extract not only two-atom near-maximally entangled states but also four-atom maximally entangled states from less entangled pure or mixed states.

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

    Institute of Scientific and Technical Information of China (English)

    黄选忠; 万忠卫; 杜宏山; 郑丽

    2013-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-04-04

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

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

    Institute of Scientific and Technical Information of China (English)

    张宏; 张新申; 颜钫; 陈放

    2001-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-01-15

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

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

    Institute of Scientific and Technical Information of China (English)

    宋伟明; 倪刚; 胡奇林; 全晓塞

    2001-01-01

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

  6. Generation of red fluorescent protein transgenic dogs.

    Science.gov (United States)

    Hong, So Gun; Kim, Min Kyu; Jang, Goo; Oh, Hyun Ju; Park, Jung Eun; Kang, Jung Taek; Koo, Ok Jae; Kim, Teoan; Kwon, Mo Sun; Koo, Bon Chul; Ra, Jeong Chan; Kim, Dae Yong; Ko, CheMyong; Lee, Byeong Chun

    2009-05-01

    Dogs (Canis familiaris) share many common genetic diseases with humans and development of disease models using a transgenic approach has long been awaited. However, due to the technical difficulty in obtaining fertilizable eggs and the unavailability of embryonic stem cells, no transgenic dog has been generated. Canine fetal fibroblasts were stably transfected with a red fluorescent protein (RFP) gene-expressing construct using retrovirus gene delivery method. Somatic cell nuclear transfer was then employed to replace the nucleus of an oocyte with the nucleus of the RFP-fibroblasts. Using this approach, we produced the first generation of transgenic dogs with four female and two male expressing RFP.

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

    Institute of Scientific and Technical Information of China (English)

    向祥蓉; 刘虹; 王佼

    2012-01-01

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

  8. Ultimate statistical physics: fluorescence of a single atom

    Science.gov (United States)

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

    2016-10-01

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

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

    Institute of Scientific and Technical Information of China (English)

    肖融; 张新智; 王昌钊; 冯礼; 秦德元; 刘霁欣

    2012-01-01

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

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

    Science.gov (United States)

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

    2009-02-20

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

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

    Institute of Scientific and Technical Information of China (English)

    梁淑轩; 吴虹; 齐学先; 郑璇; 何晓娇

    2011-01-01

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

  12. Resonance fluorescence of a trapped three-level atom

    CERN Document Server

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

    2003-01-01

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

  13. Rotary-Atomizer Electric Power Generator

    Science.gov (United States)

    Nguyen, Trieu; Tran, Tuan; de Boer, Hans; van den Berg, Albert; Eijkel, Jan C. T.

    2015-03-01

    We report experimental and theoretical results on a ballistic energy-conversion method based on a rotary atomizer working with a droplet acceleration-deceleration cycle. In a rotary atomizer, liquid is fed onto the center of a rotating flat surface, where it spreads out under the action of the centrifugal force and creates "atomized" droplets at its edge. The advantage of using a rotary atomizer is that the centrifugal force exerted on the fluid on a smooth, large surface is not only a robust form of acceleration, as it avoids clogging, but also easily allows high throughput, and produces high electrical power. We successfully demonstrate an output power of 4.9 mW and a high voltage up to 3120 V. At present, the efficiency of the system is still low (0.14%). However, the conversion mechanism of the system is fully interpreted in this paper, permitting a conceptual understanding of system operation and providing a roadmap for system optimization. This observation will open up a road for building power-generation systems in the near future.

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

    Science.gov (United States)

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

    2016-09-01

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

  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......The reliable detection of single quantum particles has revolutionized the field of quantum optics and quantum information processing. For several years, researchers have aspired to extend such detection possibilities to larger-scale, strongly correlated quantum systems 1 , 2 in order to record...

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

    Institute of Scientific and Technical Information of China (English)

    张祥楼

    2014-01-01

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

  17. Second-Generation Fluorescent Quadracyclic Adenine Analogues

    DEFF Research Database (Denmark)

    Dumat, Blaise; Bood, Mattias; Wranne, Moa S.;

    2015-01-01

    Fluorescent base analogues comprise a group of increasingly important molecules for the investigation of nucleic acid structure, dynamics, and interactions with other molecules. Herein, we report on the quantum chemical calculation aided design, synthesis, and characterization of four new putativ...

  18. Atom chip based generation of entanglement for quantum metrology

    CERN Document Server

    Riedel, Max F; Li, Yun; Hänsch, Theodor W; Sinatra, Alice; Treutlein, Philipp

    2010-01-01

    Atom chips provide a versatile `quantum laboratory on a microchip' for experiments with ultracold atomic gases. They have been used in experiments on diverse topics such as low-dimensional quantum gases, cavity quantum electrodynamics, atom-surface interactions, and chip-based atomic clocks and interferometers. A severe limitation of atom chips, however, is that techniques to control atomic interactions and to generate entanglement have not been experimentally available so far. Such techniques enable chip-based studies of entangled many-body systems and are a key prerequisite for atom chip applications in quantum simulations, quantum information processing, and quantum metrology. Here we report experiments where we generate multi-particle entanglement on an atom chip by controlling elastic collisional interactions with a state-dependent potential. We employ this technique to generate spin-squeezed states of a two-component Bose-Einstein condensate and show that they are useful for quantum metrology. The obser...

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

    Institute of Scientific and Technical Information of China (English)

    宋岳; 周虹

    2012-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    张克梅; 王文静

    2011-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    龚胜芳; 高树林; 李志华; 王红柳

    2014-01-01

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

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

    Science.gov (United States)

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

    2017-05-01

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

  3. Fluorescent lamp unit with magnetic field generating means

    Science.gov (United States)

    Grossman, M.W.; George, W.A.

    1989-08-08

    A fluorescent lamp unit having a magnetic field generating means for improving the performance of the fluorescent lamp is disclosed. In a preferred embodiment the fluorescent lamp comprises four longitudinally extending leg portions disposed in substantially quadrangular columnar array and joined by three generally U-shaped portions disposed in different planes. In another embodiment of the invention the magnetic field generating means comprises a plurality of permanent magnets secured together to form a single columnar structure disposed within a centrally located region defined by the shape of lamp envelope. 4 figs.

  4. Rotary-atomizer electric power generator

    NARCIS (Netherlands)

    Nguyen, Trieu; Tran, Tuan; de Boer, Hans L.; van den Berg, Albert; Eijkel, Jan C.T.

    2015-01-01

    We report experimental and theoretical results on a ballistic energy-conversion method based on a rotary atomizer working with a droplet acceleration-deceleration cycle. In a rotary atomizer, liquid is fed onto the center of a rotating flat surface, where it spreads out under the action of the centr

  5. Rotary-atomizer electric power generator

    NARCIS (Netherlands)

    Nguyen, Trieu; Tran, Tuan; Boer, de Hans; Berg, van den Albert; Eijkel, Jan C.T.

    2015-01-01

    We report experimental and theoretical results on a ballistic energy-conversion method based on a rotary atomizer working with a droplet acceleration-deceleration cycle. In a rotary atomizer, liquid is fed onto the center of a rotating flat surface, where it spreads out under the action of the centr

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

  7. Generation of W atomic states assisted by cavities

    Energy Technology Data Exchange (ETDEWEB)

    Becerra-Castro, E M; Cardoso, W B; Avelar, A T; Baseia, B [Instituto de Fisica, Universidade Federal de Goias, 74.001-970, Goiania (Brazil)], E-mail: wesleybcardoso@gmail.com

    2008-11-14

    We present an experimental scheme to generate a class of entangled atomic W states useful for perfect teleportation and superdense coding. It employs three two-level (Rydberg) atoms crossing two nonresonant cavities in such a way that the first and second (the second and third) atoms are entangled via atomic collision in the first (second) cavity. The experimental realization with current technology is discussed.

  8. 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.

  9. 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.

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

    Science.gov (United States)

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

    2015-01-01

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

  11. Deterministic generation of entangled coherent states for two atomic samples

    Institute of Scientific and Technical Information of China (English)

    Lu Dao-Ming; Zheng Shi-Biao

    2009-01-01

    This paper proposes an efficient scheme for deterministic generation of entangled coherent states for two atomic samples. In the scheme two collections of atoms are trapped in an optical cavity and driven by a classical field. Under certain conditions the two atomic samples evolve from an coherent state to an entangled coherent state. During the interaction the cavity mode is always in the vacuum state and the atoms have no probability of being populated in the excited state. Thus, the scheme is insensitive to both the cavity decay and atomic spontaneous emission.

  12. Generation and storage of quantum states using cold atoms

    DEFF Research Database (Denmark)

    Dantan, Aurelien Romain; Josse, Vincent; Cviklinski, Jean

    2006-01-01

    Cold cesium or rubidium atomic samples have a good potential both for generation and storage of nonclassical states of light. Generation of nonclassical states of light is possible through the high non-linearity of cold atomic samples excited close to a resonance line. Quadrature squeezing, polar......, polarization squeezing and entanglement have been demonstrated. Quantum state storage is made possible by the presence of long-lived angular momentum in the ground state. Cold atoms are thus a promising resource in quantum information.......Cold cesium or rubidium atomic samples have a good potential both for generation and storage of nonclassical states of light. Generation of nonclassical states of light is possible through the high non-linearity of cold atomic samples excited close to a resonance line. Quadrature squeezing...

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

    Science.gov (United States)

    1981-01-30

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

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

  15. Development of a portable sodium fluorescence aerosol generator model

    CERN Document Server

    LiuQun; Gao Xiao Mei; Jia Ming; Guo Chuang Cheng; Wu Tao; Liu Zhao Feng; Qiu Dan Gui

    2002-01-01

    A portable sodium fluorescence aerosol generator has been developed. It is a key equipment for in-situ testing of HEPA filters using sodium fluorescence method. The structure and technical specifications of the model generator are presented, along with its performance testing methods. The performance comparison result of the model with two French-made generators is also presented. The self-made generator has performances as follows: the average mass generating rate is 32.9 mg/h, mass median diameter of the particles 0.22 mu m and geometric standard deviation 1.58. The filtration efficiency up to 99.99% can be achieved flow-rate of ventilation system is less than 150000 m sup 3 /h. The portable model weight 25 kg, which is convenient for in situ testing

  16. Holographic generation of micro-trap arrays for single atoms

    CERN Document Server

    Bergamini, S; Jones, M; Jacubowiez, L; Browaeys, A; Grangier, P; Bergamini, Silvia; Darquie, Benoit; Jones, Matt; Jacubowiez, Lionel; Browaeys, Antoine; Grangier, Philippe

    2004-01-01

    We have generated multiple micron-sized optical dipole traps for neutral atoms using holographic techniques with a programmable liquid crystal spatial light modulator. The setup allows the storing of a single atom per trap, and the addressing and manipulation of individual trapping sites.

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

    Institute of Scientific and Technical Information of China (English)

    姜宪娟; 淦五二

    2012-01-01

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

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

    CERN Document Server

    Stroescu, Ion; Oberthaler, Markus K

    2014-01-01

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

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

    CERN Document Server

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

    2007-01-01

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

  20. High-dimensional atom localization via spontaneously generated coherence in a microwave-driven atomic system.

    Science.gov (United States)

    Wang, Zhiping; Chen, Jinyu; Yu, Benli

    2017-02-20

    We investigate the two-dimensional (2D) and three-dimensional (3D) atom localization behaviors via spontaneously generated coherence in a microwave-driven four-level atomic system. Owing to the space-dependent atom-field interaction, it is found that the detecting probability and precision of 2D and 3D atom localization behaviors can be significantly improved via adjusting the system parameters, the phase, amplitude, and initial population distribution. Interestingly, the atom can be localized in volumes that are substantially smaller than a cubic optical wavelength. Our scheme opens a promising way to achieve high-precision and high-efficiency atom localization, which provides some potential applications in high-dimensional atom nanolithography.

  1. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-15

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

  3. Ultimate Statistical Physics: fluorescence of a single atom

    CERN Document Server

    Pomeau, Yves; Ginibre, Jean

    2016-01-01

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

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

    CERN Document Server

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

    2015-01-01

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

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

    NARCIS (Netherlands)

    Kassies, Roelf

    2005-01-01

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

  6. Generation of Exotic Quantum States of a Cold Atomic Ensemble

    DEFF Research Database (Denmark)

    Christensen, Stefan Lund

    . Furthermore, the nonclassical properties of the created state is inferred through the use of atomic quadrature quasi-probability distributions. The second generated state is a collective-single-excitation state — the atomic equivalent of a single photon. This state is created by the detection of a heralding......Over the last decades quantum effects have become more and more controllable, leading to the implementations of various quantum information protocols. These protocols are all based on utilizing quantum correlation. In this thesis we consider how states of an atomic ensemble with such correlations...... can be created and characterized. First we consider a spin-squeezed state. This state is generated by performing quantum non-demolition measurements of the atomic population difference. We show a spectroscopically relevant noise reduction of -1.7dB, the ensemble is in a many-body entangled state...

  7. Ultratrace determination of tin by hydride generation in-atomizer trapping atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Průša, Libor [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, Hlavova 8, Prague 2, CZ 128 43 Czech Republic (Czech Republic); Dědina, Jiří [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic); Kratzer, Jan, E-mail: jkratzer@biomed.cas.cz [Institute of Analytical Chemistry of the ASCR, v. v. i., Veveří 97, 602 00 Brno (Czech Republic)

    2013-12-04

    Graphical abstract: -- Highlights: •In-atomizer trapping HG-AAS was optimized for Sn. •A compact quartz trap-and-atomizer device was employed. •Generation, preconcentration and atomization steps were investigated in detail. •Hundred percent preconcentration efficiency for tin was reached. •Routine analytical method was developed for Sn determination (LOD of 0.03 ng mL{sup −1} Sn). -- Abstract: A quartz multiatomizer with its inlet arm modified to serve as a trap (trap-and-atomizer device) was employed to trap tin hydride and subsequently to volatilize collected analyte species with atomic absorption spectrometric detection. Generation, atomization and preconcentration conditions were optimized and analytical figures of merit of both on-line atomization as well as preconcentration modes were quantified. Preconcentration efficiency of 95 ± 5% was found. The detection limits reached were 0.029 and 0.14 ng mL{sup −1} Sn, respectively, for 120 s preconcentration period and on-line atomization mode without any preconcentration. The interference extent of other hydride forming elements (As, Se, Sb and Bi) on tin determination was found negligible in both modes of operation. The applicability of the developed preconcentration method was verified by Sn determination in a certified reference material as well as by analysis of real samples.

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

    Institute of Scientific and Technical Information of China (English)

    马熠罡

    2012-01-01

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

  9. 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...

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

    Science.gov (United States)

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

    1993-04-01

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

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

    NARCIS (Netherlands)

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

    1992-01-01

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

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

    NARCIS (Netherlands)

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

    1992-01-01

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

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

    Science.gov (United States)

    Ito, Takashi

    2008-01-01

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

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

    Science.gov (United States)

    Ito, Takashi

    2008-01-01

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

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

    Science.gov (United States)

    Jones, Ryan; Saint, Reece; Olmos, Beatriz

    2017-01-01

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

  16. Multifunctional radio-frequency generator for cold atom experiments

    Science.gov (United States)

    Wei, Chun-hua; Yan, Shu-hua

    2016-05-01

    We present a low cost radio-frequency (RF) generator suitable for experiments with cold atoms. The RF source achieves a sub-hertz frequency with tunable resolution from 0 MHz to 400 MHz and a maximum output power of 33 dBm. Based on a direct digital synthesizer (DDS) chip, we implement a ramping capability for frequency, amplitude and phase. The system can also operate as an arbitrary waveform generator. By measuring the stability in a duration of 600 s, we find the presented device performs comparably as Agilent33522A in terms of short-term stability. Due to its excellent performance, the RF generator has been already applied to cold atom trapping experiments.

  17. Generating and probing entangled states for optical atomic clocks

    Science.gov (United States)

    Braverman, Boris; Kawasaki, Akio; Vuletic, Vladan

    2016-05-01

    The precision of quantum measurements is inherently limited by projection noise caused by the measurement process itself. Spin squeezing and more complex forms of entanglement have been proposed as ways of surpassing this limitation. In our system, a high-finesse asymmetric micromirror-based optical cavity can mediate the atom-atom interaction necessary for generating entanglement in an 171 Yb optical lattice clock. I will discuss approaches for creating, characterizing, and optimally utilizing these nonclassical states for precision measurement, as well as recent progress toward their realization. This research is supported by DARPA QuASAR, NSF, and NSERC.

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

    CERN Document Server

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

    2013-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    陈峰; 谢超

    2013-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    王长芹; 刘贵勤

    2011-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    于兆水; 张勤

    2009-01-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

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

    Institute of Scientific and Technical Information of China (English)

    蔡龙飞; 徐春秀; 张应钦; 邱新红

    2011-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    叶海辉; 谢德芳; 谢轶; 吴学进

    2012-01-01

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

  5. Generation of Exotic Quantum States of a Cold Atomic Ensemble

    DEFF Research Database (Denmark)

    Christensen, Stefan Lund

    Over the last decades quantum effects have become more and more controllable, leading to the implementations of various quantum information protocols. These protocols are all based on utilizing quantum correlation. In this thesis we consider how states of an atomic ensemble with such correlations...... — a nanofiber based light-atom interface. Using a dual-frequency probing method we measure and prepare an ensemble with a sub-Poissonian atom number distribution. This is a first step towards the implementation of more exotic quantum states.......Over the last decades quantum effects have become more and more controllable, leading to the implementations of various quantum information protocols. These protocols are all based on utilizing quantum correlation. In this thesis we consider how states of an atomic ensemble with such correlations...... can be created and characterized. First we consider a spin-squeezed state. This state is generated by performing quantum non-demolition measurements of the atomic population difference. We show a spectroscopically relevant noise reduction of -1.7dB, the ensemble is in a many-body entangled state...

  6. Spin-polarized currents generated by magnetic Fe atomic chains.

    Science.gov (United States)

    Lin, Zheng-Zhe; Chen, Xi

    2014-06-13

    Fe-based devices are widely used in spintronics because of high spin-polarization and magnetism. In this work, freestanding Fe atomic chains, the thinnest wires, were used to generate spin-polarized currents due to the spin-polarized energy bands. By ab initio calculations, the zigzag structure was found to be more stable than the wide-angle zigzag structure and had a higher ratio of spin-up and spin-down currents. By our theoretical prediction, Fe atomic chains have a sufficiently long thermal lifetime only at T ≦̸ 150 K, while C atomic chains are very stable even at T = 1000 K. This means that the spintronic devices based on Fe chains could work only at low temperatures. A system constructed by a short Fe chain sandwiched between two graphene electrodes could be used as a spin-polarized current generator, while a C chain could not be used in this way. The present work may be instructive and meaningful to further practical applications based on recent technical developments on the preparation of metal atomic chains (Proc. Natl. Acad. Sci. USA 107 9055 (2010)).

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

    CERN Document Server

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

    2015-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  9. 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.

  10. 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.

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

    Science.gov (United States)

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

    2016-10-01

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

  12. High-order-harmonic generation in atomic and molecular systems

    Science.gov (United States)

    Suárez, Noslen; Chacón, Alexis; Pérez-Hernández, Jose A.; Biegert, Jens; Lewenstein, Maciej; Ciappina, Marcelo F.

    2017-03-01

    High-order-harmonic generation (HHG) results from the interaction of ultrashort laser pulses with matter. It configures an invaluable tool to produce attosecond pulses, moreover, to extract electron structural and dynamical information of the target, i.e., atoms, molecules, and solids. In this contribution, we introduce an analytical description of atomic and molecular HHG, that extends the well-established theoretical strong-field approximation (SFA). Our approach involves two innovative aspects: (i) First, the bound-continuum and rescattering matrix elements can be analytically computed for both atomic and multicenter molecular systems, using a nonlocal short range model, but separable, potential. When compared with the standard models, these analytical derivations make possible to directly examine how the HHG spectra depend on the driven media and laser-pulse features. Furthermore, we can turn on and off contributions having distinct physical origins or corresponding to different mechanisms. This allows us to quantify their importance in the various regions of the HHG spectra. (ii) Second, as reported recently [N. Suárez et al., Phys. Rev. A 94, 043423 (2016), 10.1103/PhysRevA.94.043423], the multicenter matrix elements in our theory are free from nonphysical gauge- and coordinate-system-dependent terms; this is accomplished by adapting the coordinate system to the center from which the corresponding time-dependent wave function originates. Our SFA results are contrasted, when possible, with the direct numerical integration of the time-dependent Schrödinger equation in reduced and full dimensionality. Very good agreement is found for single and multielectronic atomic systems, modeled under the single active electron approximation, and for simple diatomic molecular systems. Interference features, ubiquitously present in every strong-field phenomenon involving a multicenter target, are also captured by our model.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-12-14

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

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

    Science.gov (United States)

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

    2013-12-14

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

  15. Atom-atom entanglement generated at early times by two-photon emission

    Energy Technology Data Exchange (ETDEWEB)

    Leon, Juan; Sabin, Carlos [Instituto de Fisica Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain)], E-mail: leon@imaff.cfmac.csic.es, E-mail: csl@imaff.cfmac.csic.es

    2009-07-15

    We analyze entanglement generation between a pair of neutral two-level atoms that are initially excited in a common electromagnetic vacuum. The nonlocal correlations that appear due to the interaction with the field can become entanglement when the field state is known. We distinguish two different situations: in the first, the field remains in the vacuum state and in the second, two photons are present in the final state. In both cases, we study the dependence of the entanglement on time and interatomic distance, at ranges related with locality issues.

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

    Science.gov (United States)

    Trache, Andreea

    2009-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-01

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

  18. Determination of Lead in Tea Garden Soil by Hydride Generation Atomic Fluorescence Spectrometry with Microwave Digestion%微波消解-氢化物发生原子荧光光谱法测定茶园土壤中的铅

    Institute of Scientific and Technical Information of China (English)

    凤海元; 时晓露; 黄勤

    2013-01-01

    样品用王水微波消解浸提,氢化物发生-原子荧光光谱法测定茶园土壤中痕量铅的含量.对样品浸取方法、实验条件、增感剂和共存元素进行了条件实验.结果表明,王水微波消解浸取,铅浸出量最大,减少了试剂用量和环境污染;铁氰化钾-盐酸羟胺体系有显著的增感作用,铁氰化钾在配制溶液时用米糠除去试剂中可能存在的铅,降低了空白;钴、锌、砷、镉等共存离子不干扰铅的测定,通过加入邻菲啰啉-硫氰酸钠消除铁和铜的干扰,提高了铅的回收率.方法检出限为0.65 μg/L,精密度(RSD,n=10)为1.89%,回收率在86.8% ~ 110.4%之间.用土壤标准物质验证,测定值与标准值相符,方法快速准确,适合于大批量样品的分析检测.%The microwave digestion system with aqua regia was developed for the determination of trace lead in tea garden soil using Hydride Generation-Atomic Fluorescence Spectrometry ( HG-AFS). The leaching methods, experimental conditions, booster and coexisting element were optimized. The largest amount of lead was leached out by microwave digestion with aqua regia, which has the advantages of less usage of reagent and less environmental pollution. An appropriate amount of potassium ferricyanide and hydroxylamine hydrochloride improved the hydride generation efficiency of Pb. The lead blank was reduced significantly when Potassium ferricyanide solution was treated with rice husk to remove Pb in the reagent. It was found that Co, Zn, As, and Cd did not interfere with the determination of lead. The addition of 1,10-phenanthroline monohydrate and sodium hydrosulfide could effectively eliminate the interferences from Fe and Cu, which improved the recovery rate of lead. The limit of detection was 0. 65 μg/L and the precision was 1. 89% (n = 10) with recoveries of 86. 8% - 110. 4% for Pb. The reliability of the method has been tested by determination of Pb in the Soils Standard Reference

  19. Determination of Water Soluble As ( Ⅲ ) and As ( Ⅴ ) in Soil by Hydride Generation-Atomic Fluorescence Spectrometry%氢化物发生-原子荧光光谱法测定土壤中水溶态砷(Ⅲ)和砷(Ⅴ)

    Institute of Scientific and Technical Information of China (English)

    于兆水; 张勤; 刘玲

    2012-01-01

    以氢气发生器为氩-氢火焰提供纯净、稳定的氢气,原子荧光光谱法测定土壤中水溶态和可交换态Sb(Ⅲ)和Sb(Ⅴ)已有应用,本研究进一步将此方法用于测定土壤样品中的As(Ⅲ)和As(Ⅴ).在0.3mol/L NaH2PO4 - Na2HPO4缓冲液中,采用氢化物发生-原子荧光光谱法测定土壤中水溶态As(Ⅲ)和总砷的含量,通过差减法计算As(Ⅴ)的含量.实验考察了0.02~0.4 mol/L NaH2PO4 - Na2 HPO4对As(Ⅲ)和As(Ⅴ)测定的影响,结果表明0.3 mol/L NaH2PO4 - Na2HPO4可以有效掩蔽As(Ⅴ).As(Ⅲ)的检出限为2.92 ng/g,总砷的检出限为2.35 ng/g;As(Ⅲ)和As(Ⅴ)的加标回收率分别为96% ~ 104%和101% ~103%.本方法不再依靠化学反应产生氢气来点燃并维持氩氢火焰,可在发生氢化反应的任何介质中测定砷,且不需要考虑酸度问题.方法操作简便,准确度高,能满足大批量样品分析要求.%Based on the determination method of Sb ( HI) and Sb ( V ) in soil, a method for the determination of water soluble As ( M ) and total arsenic in soil has been established by using Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS) in the media of 0. 3 mol/L NaH2PO4-Na2HPO4. An amount of As( V ) was obtained by subtracting As( HI ) from total arsenic. The hydrogen was provided from a hydrogen generator instead of chemical reaction to ignite a H2-Ar flame. Therefore, arsenic in any media was measurable since the arsenic was reduced into AsH3. Effects on the determination of As ( M ) and As ( V ) were investigated for concentrations of NaH2PO4-Na2HPO4 from 0. 02 mol/L to 0. 4 mol/L. The results show As( V ) can be screened by 0. 3 mol/L NaH2PO4-Na2HPO4. The detection limits were 2. 92 ng/g for As( HJ ) and 2. 35 ng/g for total As. The recoveries of As( HI) and As( V ) are 96% - 104% and 101% - 103% , respectively. The method was simple and highly accurate, meeting the requirements for multiple sample analysis.

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

    Science.gov (United States)

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

    2017-01-01

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

  1. Multiphoton fluorescence and second harmonic generation microscopy for imaging keratoconus

    Science.gov (United States)

    Sun, Yen; Lo, Wen; Lin, Sung-Jan; Lin, Wei-Chou; Jee, Shiou-Hwa; Tan, Hsin-Yuan; Dong, Chen-Yuan

    2006-02-01

    The purpose of this study is to assess the possible application of multiphoton fluorescence and second harmonic generation (SHG) microscopy for imaging the structural features of keratoconus cornea and to evaluate its potential as being a clinical in vivo monitoring technique. Using the near-infrared excitation source from a titanium-sapphire laser pumped by a diode-pumped, solid state (DPSS) laser system, we can induce and simultaneously acquire multiphoton autofluorescence and SHG signals from the cornea specimens with keratoconus. A home-modified commercial microscope system with specified optical components is used for optimal signal detection. Keratoconus cornea button from patient with typical clinical presentation of keratoconus was obtained at the time of penetrating keratoplasty. The specimen was also sent for the histological examination as comparison. In all samples of keratoconus, destruction of lamellar structure with altered collagen fiber orientation was observed within whole layer of the diseased stromal area. In addition, the orientation of the altered collagen fibers within the cone area shows a trend directing toward the apex of the cone, which might implicate the biomechanical response of the keratoconus stroma to the intraocular pressure. Moreover, increased autofluorescent cells were also found in the cone area, with increased density as one approaches the apical area. In conclusion, multiphoton autofluorescence and SHG microscopy non-invasively demonstrated the morphological features of keratoconus cornea, especially the structural alternations of the stromal lamellae. We believe that in the future the multiphoton microscopy can be applied in vivo as an effective, non-invasive diagnostic and monitoring technique for keratoconus.

  2. Generation and characterization of a stable red fluorescent ...

    African Journals Online (AJOL)

    AJL

    2012-04-12

    Apr 12, 2012 ... such as the fluorescent transgenic zebrafish (Danio rerio) and Japanese medaka ..... number in transgenic animals. Biotechniques, 37: ... Development of transgenic fish for ornamental and bioreactor by strong expression.

  3. Determination of Mercuryalkylide in Water Using High Performance Liquid Chromatography with Hydride Generation Atomic Fluorescence Detection%高效液相色谱-氢化物发生-原子荧光光谱联用技术测定水中烷基汞

    Institute of Scientific and Technical Information of China (English)

    陈邵鹏; 顾海东; 秦宏兵

    2012-01-01

    A method for the determination of Mercury species in both surface water and waste water was established by high performance liquid chromatography ( HPLC ) -hydride generation ( HG) -atomic fluorescence spectrophotometry ( AFS). Sample was extracted by dichloromethane, subsequently back-extracted by mixed extractant containing cysteine and ammonium acetate before HPLC-HG-AFS detection. Under the optimized conditions, both methyl mercury and ethyl mercury responded linearly in the concentration of 1-50μg/L. The recoveries for both standard samples and actual samples were 80%-110%. The relative standard deviations for the determination of methyl and ethylmercury with the concentration of 1μg/L were 5. 2% and 3. 9% , respectively. The detection limits for them were 0.4 ng/L and 0.7 ng/L, respectively with the American EPA methord. The proposed method is of good accuracy, high repeatability, precision, less interferences from impurities and low cost, which is benefit for expanding and applying in the common laboratory.%建立了高效液相色谱(HPLC)-氢化物发生(HG)-原子荧光光谱(AFS)联用技术分析地表水及废水中甲基汞和乙基汞的方法.样品经二氯甲烷萃取,再以半胱氨酸+乙酸铵溶液反萃取富集,并进入高效液相色谱分离,经形态分析预处理装置后,借助原子荧光光谱法检测.在优化分离条件下,甲基汞和乙基汞在1 ~ 50 μg/L范围内呈现良好的线性关系,对于标准水样、地表水和废水实际水样,加标平均回收率均为80% ~ 110%.平行进样7次1μg/L的汞混合标准溶液,甲基汞和乙基汞的色谱峰面积的相对标准偏差分别为5.2%和3.9%,检出限则分别为0.4 ng/L和0.7 ng/L.该检测方法前处理简单、回收率稳定、灵敏度和准确度高、检出限低、杂质干扰少、监测费用低,便于在普通实验室推广和应用.

  4. Determination of arsenic in antimony ingot and antimony trioxide by hydride generation-atomic fluorescence spectrometry%氢化物发生-原子荧光光谱法测定锑锭及三氧化二锑中的砷

    Institute of Scientific and Technical Information of China (English)

    钱光敏; 赵国杏

    2012-01-01

    The antimony slab and antimonous oxide samples were dissolved by sulfuric acid and hydrochloric acid, respectively. The Sb3+ in solution was precipitated with sodium hydroxide to separate trace arsenic from matrix antimony. The thiourea-ascorbic acid was added to reduce As5+ to As3+. Then, the arsenic in antimony slab and antimonous oxide was determined by atomic fluorescence spec-trometry. The hydride generation conditions were investigated: the concentration of reducing agent potassium borohydride was 25 g/L, the determination medium was 20% (V/V) hydrochloric acid, and the dosage of thiourea - ascorbic acid solution was 5 mL. The interference test of coexisting elements showed that, the interference of residual antimony in solution after precipitation could be fully eliminated by adding 1 mL of tartaric acid solution. Other impurity elements in sample did not interfere with the determination of arsenic after adding thiourea-ascorbic acid solution. The detection limit of method was 0. 156 ng/mL. The antimony slab and antimonous oxide samples were analyzed by the proposed method, and the relative standard deviation (RSD) was 0. 95%-1.2%. The determination results were consistent with those obtained by national standard methods.%采用硫酸溶解锑锭样品,盐酸溶解三氧化二锑样品,用氢氧化钠溶液使Sb3+沉淀从而使基体锑与微量砷分离,通过加入硫脲-抗坏血酸将As5+还原成As3+,然后在原子荧光仪上测定锑锭及三氧化二锑中的砷.对氢化物发生条件进行考察,确定还原剂硼氢化钾的浓度为25 g/L、测定介质为20%(V/V)盐酸、硫脲-抗坏血酸溶液用量为5 mL.共存元素干扰试验表明,沉淀后溶液中残留少量锑的干扰在加入1 mL酒石酸溶液后可以完全消除,而样品中其他杂质元素在加入硫脲-抗坏血酸溶液后不干扰砷的测定.方法的检出限为0.156 ng/mL.对锑锭及三氧化二锑样品进行分析,相对标准偏差为0.95%~1.2%,测定

  5. THE DETERMINATION OF ANTIMONY (Ⅲ) AND ANTOMONY (Ⅴ) IN GEOLOGICAL SAMPLES BY HYDRIDE GENERATION-ATOMIC FLUORESCENCE SPECTROMETRY%氢化物发生—原子荧光光谱法测定地质样品中的锑(Ⅲ)和锑(Ⅴ)

    Institute of Scientific and Technical Information of China (English)

    郝志红; 杨帆; 刑夏; 汤志勇; 张勤

    2012-01-01

    A method for the determination of antimony ( Ⅲ ) and antimony ( V ) in geological samples (stream sediments) by hydride generation-atomic fluorescence spectrometry was developed in the paper. 4. 8 mol/L HC1 could be used as the extraclant with ultrasonic-assisted extraction. In the medium of 0. 24 mol/L hydrochloric acid, antimony ( Ⅲ) could be alternatively determined with 6 g/mL sodium citrate as the masking agent for Sb (V). Then antimony ( V ) could be figured out by the subtraction method. The detection limit of the method was 0. 075 × 10 -6 for Sb ( 1) and 0. 097 × 10 -6 for Sb ( V ) , and the relative standard deviation was 1. 1 % and 0. 64% ( n = 11) for 40 ng/mL Sb ( Ⅲ ) and 40 ng/mL Sb( V ) standard solution. The proposed method was applied to the determination of antimony ( Ⅲ) and antimony ( V ) in geological samples, and a comparison between the extraction results and the aqua regia dissolution results shows that the extraction rate of antimony was higher than 80% , the recoveries were in the ranges of 83% - 107% and 98% -114% for Sb ( Ⅲ) and Sb (V) respectively.%提出了一种氢化物发生—原子荧光光谱法测定地质样品(水系沉积物)中Sb(Ⅲ)和Sb(Ⅴ)的方法.选取4.8 mol/L HC1为提取剂,采用超声波辅助提取,以6 g/mL柠檬酸钠作为Sb(Ⅴ)的掩蔽剂,在0.24 mol/L的HC1介质中选择性测定Sb(Ⅲ),用差减法求得Sb(Ⅴ).Sb(Ⅲ)的方法检出限为0.075×10-6,Sb(Ⅴ)的方法检出限为0.097×10-6.对40 ng/mL的Sb(Ⅲ)和Sb(Ⅴ)分别连续测定11次,得到相对标准偏差分别为1.1%和0.64%.应用该方法对地质样品中的Sb(Ⅲ)和Sb(Ⅴ)进行分析测定,并与王水溶解值相比较,该方法测定的总Sb提取率在80%以上,Sb(Ⅲ)和Sb(Ⅴ)的加标回收率分别为83% ~ 107%和98% ~ 114%.

  6. 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

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

    Science.gov (United States)

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

    2016-12-01

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

  8. Entanglement swapping between atom and cavity and generation of entangled state of cavity fields

    Institute of Scientific and Technical Information of China (English)

    Chen Ai-Xi; Deng Li

    2007-01-01

    This paper proposes a scheme where entanglement swapping between atom and cavity can be realized. A-type three-level atoms interacting resonantly with cavity field are considered. By detecting atom and cavity field, it realizes entanglement swapping between atom and cavity. It uses the technique of entanglement swapping to generate an entangled state of two cavity fields by measuring on atoms. It discusses the experimental feasibility of the proposed scheme and application of entangled state of cavity fields.

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

    CERN Document Server

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-10-14

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

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

    CERN Document Server

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

    2006-01-01

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

  12. Dielectric barrier discharge plasma atomizer for hydride generation atomic absorption spectrometry—Performance evaluation for selenium

    Energy Technology Data Exchange (ETDEWEB)

    Duben, Ondřej [Institute of Analytical Chemistry of the CAS, v.v.i., Veveří 97, CZ-602 00 Brno (Czech Republic); Faculty of Science, Department of Analytical Chemistry, Charles University in Prague, Hlavova 8, Prague, CZ 128 43 Czech Republic (Czech Republic); Boušek, Jaroslav [Faculty of Electrical Engineering and Communications, Brno University of Technology, Technická 1058/10, 61600 Brno (Czech Republic); Dědina, Jiří [Institute of Analytical Chemistry of the CAS, v.v.i., Veveří 97, CZ-602 00 Brno (Czech Republic); Kratzer, Jan, E-mail: jkratzer@biomed.cas.cz [Institute of Analytical Chemistry of the CAS, v.v.i., Veveří 97, CZ-602 00 Brno (Czech Republic)

    2015-09-01

    Atomization of selenium hydride in a quartz dielectric barrier discharge (DBD) atomizer was optimized and its performance was compared to that of the externally heated quartz multiatomizer. Argon was found as the best DBD discharge gas employing a flow rate of 75 ml min{sup −1} Ar while the DBD power was optimized at 14 W. The detection limits reached 0.24 ng ml{sup −1} Se in the DBD and 0.15 ng ml{sup −1} Se in the multiatomizer. The tolerance of DBD to interferences is even better than with the multiatomizer. - Highlights: • SeH{sub 2} atomization in a dielectric barrier discharge (DBD) was optimized for AAS. • Atomizer performance was compared for DBD and externally heated quartz atomizer. • Detection limits were quantified and interferences were studied in both atomizers. • Atomization efficiency in the DBD was estimated.

  13. Generation of superpositions of coherent states for an atomic sample in cavity QED

    Institute of Scientific and Technical Information of China (English)

    Zheng Shi-Biao

    2009-01-01

    This paper proposes a scheme for generation of superpositions of coherent states of the effective bosonic mode in a collection of atoms. In the scheme an atomic sample interacts with a slightly detuned cavity mode and a resonant strong classical field. Under certain conditions the atomic system evolves from a coherent state to a superposition of coherent states.

  14. Atomic quantum superposition state generation via optical probing

    DEFF Research Database (Denmark)

    Nielsen, Anne Ersbak Bang; Poulsen, Uffe Vestergaard; Negretti, Antonio

    2009-01-01

    We analyze the performance of a protocol to prepare an atomic ensemble in a superposition of two macroscopically distinguishable states. The protocol relies on conditional measurements performed on a light field, which interacts with the atoms inside an optical cavity prior to detection, and we...

  15. Robust generation of high-fidelity entangled states for multiple atoms

    Institute of Scientific and Technical Information of China (English)

    Lin Li-Hua

    2009-01-01

    A scheme is presented for generating entangled states of multiple atoms in a cavity. In the scheme the atoms simultaneously interact with a cavity mode, with the first atom driven by two classical fields and the other atoms driven by a classical field. Our scheme is valid even if the cavity decay rate is larger than the effective coupling strength, which is important for experiment. The generation of entangled states is conditional on the detection of a photon decaying from the cavity and thus the fidelity of the entangled state is insensitive to the detection inefficiency. Furthermore, the scheme can be applied to the case with any number of atoms in principle.

  16. Coherence of a squeezed sodium atom laser generated from Raman output coupling

    Institute of Scientific and Technical Information of China (English)

    Huiyong He; Chunjia Huang

    2009-01-01

    The coherence of a squeezed sodium atom laser generated from a Raman output coupler,in which the sodium atoms in Bose-Einstein condensate (BEC) intcract with two light beams consisting of a weaker squeezed coherent probe light and a stronger classical coupling light,is investigated.The results show that in the case of a large mean number of BEC atoms and a weaker probe light field,the atom laser is antibunching,and this atom laser is second-order coherent if the number of BEC atoms in traps is large enough.

  17. Generation of an Entangled State of Two Multilevel Atoms in Cavity QED

    Institute of Scientific and Technical Information of China (English)

    ZHAN Zhi-Ming; YANG Wen-Xing; LI Jia-Hua

    2004-01-01

    @@ We present a simple scheme to generate a maximally entangled state of two four-level Rydberg atoms with a nonresonant cavity by cavity-assisted collisions. By using this scheme, the maximally entangled state of two N-level (N > 4) Rydberg atoms can also be obtained. During the passage of the atoms through the cavity field,they are only virtually excited. There is no quantum information that will be transferred from the atoms to the cavity in this case.

  18. Generation of transgenic dogs that conditionally express green fluorescent protein.

    Science.gov (United States)

    Kim, Min Jung; Oh, Hyun Ju; Park, Jung Eun; Kim, Geon A; Hong, So Gun; Jang, Goo; Kwon, Mo Sun; Koo, Bon Chul; Kim, Teoan; Kang, Sung Keun; Ra, Jeong Chan; Ko, Chemyong; Lee, Byeong Chun

    2011-06-01

    We report the creation of a transgenic dog that conditionally expresses eGFP (enhanced green fluorescent protein) under the regulation of doxycycline. Briefly, fetal fibroblasts infected with a Tet-on eGFP vector were used for somatic cell nuclear transfer. Subsequently reconstructed oocytes were transferred to recipients. Three clones having transgenes were born and one dog was alive. The dog showed all features of inducible expression of eGFP upon doxycycline administration, and successful breeding resulted in eGFP-positive puppies, confirming stable insertion of the transgene into the genome. This inducible dog model will be useful for a variety of medical research studies.

  19. Velocity distribution measurements in atomic beams generated using laser induced back-ablation

    CERN Document Server

    Denning, A; Lee, S; Ammonson, M; Bergeson, S D

    2008-01-01

    We present measurements of the velocity distribution of calcium atoms in an atomic beam generated using a dual-stage laser back-ablation apparatus. Distributions are measured using a velocity selective Doppler time-of-flight technique. They are Boltzmann-like with rms velocities corresponding to temperatures above the melting point for calcium. Contrary to a recent report in the literature, this method does not generate a sub-thermal atomic beam.

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

    Institute of Scientific and Technical Information of China (English)

    陆建平; 谭芳维; 石建荣

    2012-01-01

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

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

    Science.gov (United States)

    Staii, Cristian

    2014-03-01

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

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

    Science.gov (United States)

    Kobayashi, S; Nakahara, T; Musha, S

    1979-10-01

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

  3. Generation of Entangled Bloch States for Two Atomic Samples Trapped in Separated Cavities

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shi-Biao

    2007-01-01

    A scheme is presented for the generation of entangled states for two atomic ensembles trapped in two distant cavities.In the scheme,each atomic sample is initially in a Bloch state and the cavity mode is initially in a coherent state with a small amplitude.The dispersive atom-cavity interaction leads to a photon-number dependent phase shift on the atomic system.The detection of a photon leaking from the cavities makes the two atomic samples collapse to an entangled Bloch state.

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

    Science.gov (United States)

    Weng, Di

    2005-12-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2013-01-01

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

  6. 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}.

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

    Science.gov (United States)

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

    2017-02-01

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

  8. Generation of transgenic Wuzhishan miniature pigs expressing monomeric red fluorescent protein by somatic cell nuclear transfer.

    Science.gov (United States)

    Lu, Yue; Kang, Jin-Dan; Li, Suo; Wang, Wei; Jin, Jun-Xue; Hong, Yu; Cui, Cheng-du; Yan, Chang-Guo; Yin, Xi-Jun

    2013-08-01

    Red fluorescent protein and its variants enable researchers to study gene expression, localization, and protein-protein interactions in vitro in real-time. Fluorophores with higher wavelengths are usually preferred since they efficiently penetrate tissues and produce less toxic emissions. A recently developed fluorescent protein marker, monomeric red fluorescent protein (mRFP1), is particularly useful because of its rapid maturation and minimal interference with green fluorescent protein (GFP) and GFP-derived markers. We generated a pCX-mRFP1-pgk-neoR construct and evaluated the ability of mRFP1 to function as a fluorescent marker in transgenic Wuzhishan miniature pigs. Transgenic embryos were generated by somatic cell nuclear transfer (SCNT) of nuclei isolated from ear fibroblasts expressing mRFP1. Embryos generated by SCNT developed into blastocysts in vitro (11.65%; 31/266). Thereafter, a total of 685 transgenic embryos were transferred into the oviducts of three recipients, two of which became pregnant. Of these, one recipient had six aborted fetuses, whereas the other recipient gave birth to four offspring. All offspring expressed the pCX-mRFP1-pgk-neoR gene as shown by PCR and fluorescence in situ hybridization analysis. The transgenic pigs expressed mRFP1 in all organs and tissues at high levels. These results demonstrate that Wuzhishan miniature pigs can express mRFP1. To conclude, this transgenic animal represents an excellent model with widespread applications in medicine and agriculture.

  9. Charged oscillator quantum state generation with Rydberg atoms

    CERN Document Server

    Stevenson, Robin; Hofferberth, Sebastian; Lesanovsky, Igor

    2016-01-01

    We explore the possibility of engineering quantum states of a charged mechanical oscillator by coupling it to a stream of atoms in superpositions of high-lying Rydberg states. Our scheme relies on the driving of a two-phonon resonance within the oscillator by coupling it to an atomic two-photon transition. This approach effectuates a controllable open system dynamics on the oscillator that permits the creation of squeezed and other non-classical states. We show that these features are robust to thermal noise arising from a coupling of the oscillator with the environment. The possibility to create non-trivial quantum states of mechanical systems, provided by the proposed setup, is central to applications such as sensing and metrology and moreover allows the exploration of fundamental questions concerning the boundary between classical and quantum mechanical descriptions of macroscopic objects.

  10. Efficient Scheme for the Generation of Atomic Schroedinger Cat States in an Optical Cavity

    Institute of Scientific and Technical Information of China (English)

    ZHENGShi-Biao; LINLi-Hua; JIANGYun-Kun

    2003-01-01

    An efficient scheme is proposed for the generation of atomic Schroedinger cat states in an optical cavity. In the scheme N three-level atoms are loaded in the optical cavity. Raman coupling of two ground states is achieved via a laser tield and the cavity mode. The cavity mode is always in the vacuum state and the atoms have no probability of being populated in the excited state. Thus, the scheme is insensitive to both the cavity decay and spontaneous emission.

  11. Generation of SU(2) Coherent States for a Cavity Mode and a Collective Atomic Mode

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shi-Biao

    2009-01-01

    We propose a scheme for generation of SU(2) coherent states for an atomic ensemble and a cavity mode. In the scheme a collection of two-level atoms resonantly interact with a single-mode quantized field. Under certain conditions, the system can evolve from a Fock state to a highly entangled SU(2) coherent state. The operation speed increases as the number of atoms increases, which is important in view of decoherence.

  12. Efficient Scheme for the Generation of Atomic Schrodinger Cat States in an Optical Cavity

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shi-Biao; LIN Li-Hua; JIANG Yun-Kun

    2003-01-01

    An efficient scheme is proposed for the generation of atomic Schrodinger cat states in an optical cavity. Inthe scheme N three-level atoms are loaded in the optical cavity. Raman coupling of two ground states is achieved via alaser field and the cavity mode. The cavity mode is always in the vacuum state and the atoms have no probability ofbeing populated in the excited state. Thus, the scheme is insensitive to both the cavity decay and spontaneous emission.

  13. Adapted Gaussian basis sets for atoms from Li through Xe generated with the generator coordinate Hartree-Fock method

    Directory of Open Access Journals (Sweden)

    CASTRO EUSTÁQUIO V. R. DE

    2001-01-01

    Full Text Available The generator coordinate Hartree-Fock method is used to generate adapted Gaussian basis sets for the atoms from Li (Z=3 through Xe (Z=54. In this method the Griffin-Hill-Wheeler-Hartree-Fock equations are integrated through the integral discretization technique. The wave functions generated in this work are compared with the widely used Roothaan-Hartree-Fock wave functions of Clementi and Roetti (1974, and with other basis sets reported in the literature. For all atoms studied, the errors in our total energy values relatively to the numerical Hartree-Fock limits are always less than 7.426 mhartree.

  14. Hydride generation – in-atomizer collection of Pb in a quartz trap-and-atomizer device for atomic absorption spectrometry – an interference study

    Energy Technology Data Exchange (ETDEWEB)

    Novotný, Pavel [Institute of Analytical Chemistry of the ASCR, v.v.i., Veveří 97, 602 00 Brno (Czech Republic); High School in Hořice, Husova 1414, 508 01 Hořice (Czech Republic); Kratzer, Jan, E-mail: jkratzer@biomed.cas.cz [Institute of Analytical Chemistry of the ASCR, v.v.i., Veveří 97, 602 00 Brno (Czech Republic)

    2013-01-01

    Interferences of selected hydride forming elements (As, Sb, Bi, Se and Sn) on lead determination by hydride generation atomic absorption spectrometry were extensively studied in both on-line atomization and preconcentration (collection) modes. The commonly used on-line atomization mode was found free of significant interferences, whereas strong interference from Bi was observed when employing the preconcentration mode with plumbane collection in a quartz trap-and-atomizer device. Interference of Bi seems to take place in the preconcentration step. Interference of Bi in the collection mode cannot be reduced by increased hydrogen radical amount in the trap and/or the atomizer. - Highlights: ► Interference study on Pb determination by in-atomizer trapping was performed for the first time. ► Bi was found as a severe interferent in the preconcentration mode (Pb:Bi ratio 1:100). ► No interference was found in the on-line atomization (no preconcentration). ► Bi interference occurs during preconcentration.

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

    Science.gov (United States)

    Zhang, Qun; Chen, Yang; Keil, Mark

    2009-03-01

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

  16. High-Speed Generation of Entangled States for Two Three-Level Atoms

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shi-Biao

    2007-01-01

    A scheme is presented for generating entangled states for two three-level atoms in a cavity. In the scheme two atoms simultaneously interact with a cavity mode with a small detuning. Thus, the operation time is very short,which is important in view of decoherence.

  17. Straightforward biodegradable nanoparticle generation through megahertz-order ultrasonic atomization

    Science.gov (United States)

    Forde, Gareth; Friend, James; Williamson, Tom

    2006-08-01

    Simple and reliable formation of biodegradable nanoparticles formed from poly-ɛ-caprolactone was achieved using 1.645MHz piston atomization of a source fluid of 0.5% w/v of the polymer dissolved in acetone; the particles were allowed to descend under gravity in air 8cm into a 1mM solution of sodium dodecyl sulfate. After centrifugation to remove surface agglomerations, a symmetric monodisperse distribution of particles ϕ 186nm (SD =5.7, n =6) was obtained with a yield of 65.2%.

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

    Science.gov (United States)

    Basché, Thomas; Hinze, Gerald; Stöttinger, Sven

    2016-09-01

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

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

    Science.gov (United States)

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

    2014-02-01

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

  20. Influences of Doppler effect on spontaneously generated coherence in a Rb atom

    Science.gov (United States)

    Song, Zhuo; Zheng, Y.

    2015-11-01

    We study the influences of Doppler effect on spontaneously generated coherence in a Rb atom driven by a probe field and two control fields. We show that the propagating directions of the lasers and the wave-vector mismatch have influence on the absorption properties of the atom. By employing the Doppler effect and spontaneous generated coherence, the ultra-narrow lines in probe absorption profile near two-photon resonant position can be obtained.

  1. A simple scheme for generating multi-atom GHZ state via cavity QED

    Institute of Scientific and Technical Information of China (English)

    Wang Jun; Yu Long-Bao; Ye Liu

    2007-01-01

    This paper proposes a simple scheme for generating a three-atom GHZ state via cavity quantum electrodynamics (QED). The task can be achieved through the interaction between two EPR states, which can be prepared easily with current technology. In this scheme, the cavity field is only virtually excited during the interaction process, and no quantum information transfer between the atoms and the cavity is required. Thus it greatly prolongs the efficient decoherent time. Moreover, this scheme is also applicable for generating an .N-atom GHZ state.

  2. Robust Generation of Three-Particle W State with Atoms Trapped in Separate Cavities

    Institute of Scientific and Technical Information of China (English)

    辛斌; 贾仁需; 郑亦庄

    2012-01-01

    This paper presents a scheme for generating three-particle W state of remote atoms trapped in leaky cavities.The scheme uses cavity decay to inject photons into a setup of optical devices which consist of a series of beam splitters and photon detectors.Photon detection on the output mode projects the atomic state into the W state.In the condition of “weakly driven approach”,it shows that the scheme is robust and has high fidelity.It also points out that the scheme is scalable to generate multi-atomic W state.

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

    CERN Document Server

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

    2016-01-01

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

  4. Efficient Raman Sideband Generation in a Coherent Atomic Medium

    CERN Document Server

    Huss, A F; Lammegger, R; Korsunsky, E A; Windholz, L

    2000-01-01

    We demonstrate the efficient generation of Raman sidebands in a medium coherently prepared in a dark state by continuous-wave low-intensity laser radiation. Our experiment is performed in sodium vapor excited in $\\Lambda $ configuration on the D$_{1}$ line by two laser fields of resonant frequencies $\\omega_{1}$ and $\\omega_{2}$, and probed by a third field $% \\omega_{3}$. First-order sidebands for frequencies $\\omega_{1}$, $\\omega_{2}$ and up to the third-order sidebands for frequency $\\omega_{3}$ are observed. The generation starts at a power as low as 10 microwatt for each input field. Dependencies of the intensities of both input and generated waves on the frequency difference ($\\omega_{1}-\\omega_{2}$), on the frequency $\\omega_{3}$ and on the optical density are investigated.

  5. Atoms

    Institute of Scientific and Technical Information of China (English)

    刘洪毓

    2007-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-03-13

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

  7. A New Method for Determination of Arsenic and Mercury in Copper Concentrates: By High pressure airproof Microwave Digestion,Sequential Injection,Hydride Generation,and Atomic Fluorescence Spectrometry%一种检测铜精矿中砷和汞含量的新方法——高压密封微波消解-顺序注射-氢化物发生-原子荧光光谱法

    Institute of Scientific and Technical Information of China (English)

    苏明跃; 杨丽飞; 郭芬

    2011-01-01

    利用高压密封微波消解和顺序注射-氢化物发生-原子荧光光谱两项技术建立了检测铜精矿中砷、汞含量的新方法,并通过试验确定了适宜的检测条件.研究结果表明:本方法对砷的检出限为0.02μg/L,对汞的检出限为0.05μg/L;检测铜精矿中砷、汞的含量时,砷、汞的回收率分别为94.3%~107.0%和91.0%~102.0%,检测结果相对标准偏差分别在0.93%~1.97%之间和3.11%~8.07%之间,并且检测结果与认定值和国家标准方法测定值一致.%A new method for the determinations of arsenic content and mercury content in copper concentrates was founded by adopting two processes of high pressure-airproof microwave digestion and the sequential injection-hydride generation -atomic fluorescence spectrometry. Through tests, the optimum conditions for detection were determined. The tests resuits indicated that the detection limit of arsenic was 0.02 μg/L and the detection limit of mercury was 0.05 μg/L by this method. While detecting arsenic and mercury content in copper concentrate, it is found that the arsenic and mercury recovery rates reached 94.3% ~ 107.0% and 91.0% ~ 102.0% respectively with relative standard of deviation between 0.93% ~1.97% for arsenic and 3.11% ~ 8.07% for mercury. Also, these detecting results are in good agreement with the certified values and the values by the national standard method.

  8. Generation of multipartite entangled states for chains of atoms in the framework of cavity-QED

    Energy Technology Data Exchange (ETDEWEB)

    Gonta, Denis

    2010-07-07

    Cavity quantum electrodynamics is a research field that studies electromagnetic fields in confined spaces and the radiative properties of atoms in such fields. Experimentally, the simplest example of such system is a single atom interacting with modes of a high-finesse resonator. Theoretically, such system bears an excellent framework for quantum information processing in which atoms and light are interpreted as bits of quantum information and their mutual interaction provides a controllable entanglement mechanism. In this thesis, we present several practical schemes for generation of multipartite entangled states for chains of atoms which pass through one or more high-finesse resonators. In the first step, we propose two schemes for generation of one- and two-dimensional cluster states of arbitrary size. These schemes are based on the resonant interaction of a chain of Rydberg atoms with one or more microwave cavities. In the second step, we propose a scheme for generation of multipartite W states. This scheme is based on the off-resonant interaction of a chain of three-level atoms with an optical cavity and a laser beam. We describe in details all the individual steps which are required to realize the proposed schemes and, moreover, we discuss several techniques to reveal the non-classical correlations associated with generated small-sized entangled states. (orig.)

  9. Generation of multipartite continuous-variable entanglement via atomic spin wave: Heisenberg-Langevin approach.

    Science.gov (United States)

    Yang, Xihua; Shang, Jie; Xue, Bolin; Zhou, Yuanyuan; Xiao, Min

    2014-05-19

    We conduct theoretical studies on the effects of various parameters on generation of multipartite continuous-variable entanglement via atomic spin wave induced by the strong coupling and probe fields in the Λ-type electromagnetically induced transparency configuration in a realistic atomic ensemble by using the Heisenberg-Langevin formalism. It is shown that the increase of the atomic density and/or Rabi frequencies of the scattering fields, as well as the decrease of the coherence decay rate of the lower doublet would strengthen the degree of multipartite entanglement. This provides a clear evidence that the creation of multicolor multipartite entangled narrow-band fields to any desired number with a long correlation time can be achieved conveniently by using atomic spin wave in an atomic ensemble with large optical depth, which may find interesting applications in quantum information processing and quantum networks.

  10. 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

  11. Generation of broadband spontaneous parametric fluorescence using multiple bulk nonlinear crystals

    CERN Document Server

    Okano, Masayuki; Tanaka, Akira; Subashchandran, Shanthi; Takeuchi, Shigeki; 10.1364/OE.20.013977

    2012-01-01

    We propose a novel method for generating broadband spontaneous parametric fluorescence by using a set of bulk nonlinear crystals (NLCs). We also demonstrate this scheme experimentally. Our method employs a superposition of spontaneous parametric fluorescence spectra generated using multiple bulk NLCs. A typical bandwidth of 160 nm (73 THz) with a degenerate wavelength of 808 nm was achieved using two beta-barium-borate (BBO) crystals, whereas a typical bandwidth of 75 nm (34 THz) was realized using a single BBO crystal. We also observed coincidence counts of generated photon pairs in a non-collinear configuration. The bandwidth could be further broadened by increasing the number of NLCs. Our demonstration suggests that a set of four BBO crystals could realize a bandwidth of approximately 215 nm (100 THz).We also discuss the stability of Hong-Ou-Mandel two-photon interference between the parametric fluorescence generated by this scheme. Our simple scheme is easy to implement with conventional NLCs and does not...

  12. Generation of broadband spontaneous parametric fluorescence using multiple bulk nonlinear crystals.

    Science.gov (United States)

    Okano, Masayuki; Okamoto, Ryo; Tanaka, Akira; Subashchandran, Shanthi; Takeuchi, Shigeki

    2012-06-18

    We propose a novel method for generating broadband spontaneous parametric fluorescence by using a set of bulk nonlinear crystals (NLCs). We also demonstrate this scheme experimentally. Our method employs a superposition of spontaneous parametric fluorescence spectra generated using multiple bulk NLCs. A typical bandwidth of 160 nm (73 THz) with a degenerate wavelength of 808 nm was achieved using two β-barium-borate (BBO) crystals, whereas a typical bandwidth of 75 nm (34 THz) was realized using a single BBO crystal. We also observed coincidence counts of generated photon pairs in a non-collinear configuration. The bandwidth could be further broadened by increasing the number of NLCs. Our demonstration suggests that a set of four BBO crystals could realize a bandwidth of approximately 215 nm (100 THz). We also discuss the stability of Hong-Ou-Mandel two-photon interference between the parametric fluorescence generated by this scheme. Our simple scheme is easy to implement with conventional NLCs and does not require special devices.

  13. Efficient and robust generation of maximally entangled states of two atomic ensembles by adiabatic quantum feedback

    CERN Document Server

    Lisi, A D; Illuminati, F; Vitali, D; Lisi, Antonio Di; Siena, Silvio De; Illuminati, Fabrizio; Vitali, David

    2004-01-01

    We introduce an efficient and robust scheme to generate maximally entangled states of two atomic ensembles. The scheme is based on quantum non-demolition measurements of total atomic populations and on quantum feedback conditioned by the measurements outputs. The high efficiency of the scheme is tested and confirmed numerically for photo-detection with ideal efficiency as well as in the presence of losses.

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

    Science.gov (United States)

    Cizdziel, James V.

    2011-01-01

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

  15. 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. Fast adiabatic quantum state transfer and entanglement generation between two atoms via dressed states

    Science.gov (United States)

    Wu, Jin-Lei; Ji, Xin; Zhang, Shou

    2017-01-01

    We propose a dressed-state scheme to achieve shortcuts to adiabaticity in atom-cavity quantum electrodynamics for speeding up adiabatic two-atom quantum state transfer and maximum entanglement generation. Compared with stimulated Raman adiabatic passage, the dressed-state scheme greatly shortens the operation time in a non-adiabatic way. By means of some numerical simulations, we determine the parameters which can guarantee the feasibility and efficiency both in theory and experiment. Besides, numerical simulations also show the scheme is robust against the variations in the parameters, atomic spontaneous emissions and the photon leakages from the cavity.

  17. Plasmonic enhancement of High Harmonic Generation revisited: Predominance of Atomic Line Emission

    Directory of Open Access Journals (Sweden)

    Ropers C.

    2013-03-01

    Full Text Available We demonstrate nanostructure-enhanced extreme ultraviolet fluorescence from noble gases driven by low-energy, few-cycle light pulses. Despite sufficient local intensities, plasmon-enhanced high harmonic generation is not observed, which follows from the small, nanometer-size coherent source volume.

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

    DEFF Research Database (Denmark)

    Lu, Weifang; Ou, Yiyu; Jokubavicius, Valdas

    2016-01-01

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

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

    Science.gov (United States)

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

    2002-11-01

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

  20. High-order harmonic generation from Rydberg atoms driven by plasmonic-enhanced laser fields

    CERN Document Server

    Tikman, Y; Ciappina, M F; Chacon, A; Altun, Z; Lewenstein, M

    2015-01-01

    We theoretically investigate high-order harmonic generation (HHG) in Rydberg atoms driven by spatially inhomogeneous laser fields, induced, for instance, by plasmonic enhancement. It is well known that the laser intensity should to exceed certain threshold in order to generate HHG, when noble gas atoms in their ground state are used as an active medium. One way to enhance the coherent light coming from a conventional laser oscillator is to take advantage of the amplification obtained by the so-called surface plasmon polaritons, created when a low intensity laser field is focused onto a metallic nanostructure. The main limitation of this scheme is the low damage threshold of the materials employed in the nanostructures engineering. In this work we propose to use Rydberg atoms, driven by spatially inhomogeneous, plasmonic-enhanced laser fields, for HHG. We exhaustively discuss the behaviour and efficiency of these systems in the generation of coherent harmonic emission. To this aim we numerically solve the time...

  1. 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.

  2. Broadband photon pair generation in green fluorescent proteins through spontaneous four-wave mixing.

    Science.gov (United States)

    Shi, Siyuan; Thomas, Abu; Corzo, Neil V; Kumar, Prem; Huang, Yuping; Lee, Kim Fook

    2016-04-14

    Recent studies in quantum biology suggest that quantum mechanics help us to explore quantum processes in biological system. Here, we demonstrate generation of photon pairs through spontaneous four-wave mixing process in naturally occurring fluorescent proteins. We develop a general empirical method for analyzing the relative strength of nonlinear optical interaction processes in five different organic fluorophores. Our results indicate that the generation of photon pairs in green fluorescent proteins is subject to less background noises than in other fluorophores, leading to a coincidence-to-accidental ratio ~145. As such proteins can be genetically engineered and fused to many biological cells, our experiment enables a new platform for quantum information processing in a biological environment such as biomimetic quantum networks and quantum sensors.

  3. Broadband photon pair generation in green fluorescent proteins through spontaneous four-wave mixing

    Science.gov (United States)

    Shi, Siyuan; Thomas, Abu; Corzo, Neil V.; Kumar, Prem; Huang, Yuping; Lee, Kim Fook

    2016-04-01

    Recent studies in quantum biology suggest that quantum mechanics help us to explore quantum processes in biological system. Here, we demonstrate generation of photon pairs through spontaneous four-wave mixing process in naturally occurring fluorescent proteins. We develop a general empirical method for analyzing the relative strength of nonlinear optical interaction processes in five different organic fluorophores. Our results indicate that the generation of photon pairs in green fluorescent proteins is subject to less background noises than in other fluorophores, leading to a coincidence-to-accidental ratio ~145. As such proteins can be genetically engineered and fused to many biological cells, our experiment enables a new platform for quantum information processing in a biological environment such as biomimetic quantum networks and quantum sensors.

  4. 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.

  5. Determination of tellurium by hydride generation with in situ trapping flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Matusiewicz, H.; Krawczyk, M. [Politechn Poznanska, Poznan (Poland)

    2007-03-15

    The analytical performance of coupled hydride generation - integrated atom trap (HG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system was evaluated for determination of Te in reference material (GBW 07302 Stream Sediment), coal fly ash and garlic. Tellurium, using formation of H{sub 2}Te vapors, is atomized in air-acetylene flame-heated IAT. A new design HG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangernents (a water-cooled single silica tube, double-slotted quartz tube or an 'integrated trap') was investigated. An improvement in detection limit was achieved compared with using either of the above atom trapping techniques separately. The concentration detection limit, defined as 3 times the blank standard deviation (3{sigma}), was 0.9 ng mL{sup -1} for Te. For a 2 min in situ preconcentration time (sample volume of 2 mL), sensitivity enhancement compared to flame AAS, was 222 fold, using the hydride generation atom trapping technique. The sensitivity can be further improved by increasing the collection time. The precision, expressed as RSD, was 7.0% (n = 6) for Te. The accuracy of the method was verified using a certified reference material (GBW 07302 Stream Sediment) by aqueous standard calibration curves. The measured Te contents of the reference material was in agreement with the information value. The method was successfully applied to the determination of tellurium in coal fly ash and garlic.

  6. Carrier-wave Rabi-flopping signatures in high-order harmonic generation for alkali atoms.

    Science.gov (United States)

    Ciappina, M F; Pérez-Hernández, J A; Landsman, A S; Zimmermann, T; Lewenstein, M; Roso, L; Krausz, F

    2015-04-10

    We present a theoretical investigation of carrier-wave Rabi flopping in real atoms by employing numerical simulations of high-order harmonic generation (HHG) in alkali species. Given the short HHG cutoff, related to the low saturation intensity, we concentrate on the features of the third harmonic of sodium (Na) and potassium (K) atoms. For pulse areas of 2π and Na atoms, a characteristic unique peak appears, which, after analyzing the ground state population, we correlate with the conventional Rabi flopping. On the other hand, for larger pulse areas, carrier-wave Rabi flopping occurs, and is associated with a more complex structure in the third harmonic. These characteristics observed in K atoms indicate the breakdown of the area theorem, as was already demonstrated under similar circumstances in narrow band gap semiconductors.

  7. Carrier-wave Rabi flopping signatures in high-order harmonic generation for alkali atoms

    CERN Document Server

    Ciappina, M F; Landsman, A S; Zimmermann, T; Lewenstein, M; Roso, L; Krausz, F

    2015-01-01

    We present the first theoretical investigation of carrier-wave Rabi flopping in real atoms by employing numerical simulations of high-order harmonic generation (HHG) in alkali species. Given the short HHG cutoff, related to the low saturation intensity, we concentrate on the features of the third harmonic of sodium (Na) and potassium (K) atoms. For pulse areas of 2$\\pi$ and Na atoms, a characteristic unique peak appears, which, after analyzing the ground state population, we correlate with the conventional Rabi flopping. On the other hand, for larger pulse areas, carrier-wave Rabi flopping occurs, and is associated with a more complex structure in the third harmonic. These new characteristics observed in K atoms indicate the breakdown of the area theorem, as was already demonstrated under similar circumstances in narrow band gap semiconductors.

  8. Composite pulses in Hyper-Ramsey spectroscopy for the next generation of atomic clocks

    Science.gov (United States)

    Zanon-Willette, T.; Minissale, M.; Yudin, V. I.; Taichenachev, A. V.

    2016-06-01

    The next generation of atomic frequency standards based on an ensemble of neutral atoms or a single-ion will provide very stringent tests in metrology, applied and fundamental physics requiring a new step in very precise control of external systematic corrections. In the proceedings of the 8th Symposium on Frequency Standards and Metrology, we present a generalization of the recent Hyper-Ramsey spectroscopy with separated oscillating fields using composites pulses in order to suppress field frequency shifts induced by the interrogation laser itself. Sequences of laser pulses including specific selection of phases, frequency detunings and durations are elaborated to generate spectroscopic signals with a strong reduction of the light-shift perturbation by off resonant states. New optical clocks based on weakly allowed or completely forbidden transitions in atoms, ions, molecules and nuclei will benefit from these generalized Ramsey schemes to reach relative accuracies well below the 10-18 level.

  9. Composite pulses in Hyper-Ramsey spectroscopy for the next generation of atomic clocks

    CERN Document Server

    Zanon-Willette, T; Yudin, V I; Taichenachev, A V

    2016-01-01

    The next generation of atomic frequency standards based on an ensemble of neutral atoms or a single-ion will provide very stringent tests in metrology, applied and fundamental physics requiring a new step in very precise control of external systematic corrections. In the proceedings of the 8th Symposium on Frequency Standards and Metrology, we present a generalization of the recent Hyper-Ramsey spectroscopy with separated oscillating fields using composites pulses in order to suppress field frequency shifts induced by the interrogation laser itself. Sequences of laser pulses including specific selection of phases, frequency detunings and durations are elaborated to generate spectroscopic signals with a strong reduction of the light-shift perturbation by off resonant states. New optical clocks based on weakly allowed or completely forbidden transitions in atoms, ions, molecules and nuclei will benefit from these generalized Ramsey schemes to reach relative accuracies well below the 10$^{-18}$ level.

  10. 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.

  11. 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.

  12. Vapor generationatomic spectrometric techniques. Expanding frontiers through specific-species preconcentration. A review

    Energy Technology Data Exchange (ETDEWEB)

    Gil, Raúl A.; Pacheco, Pablo H.; Cerutti, Soledad [Área de Química Analítica, Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Ciudad de San Luis 5700 (Argentina); Instituto de Química de San Luis, INQUISAL, Centro Científico-Tecnológico de San Luis (CCT-San Luis), Consejo Nacional de Investigaciones Científicas y Universidad Nacional de San Luis, Ciudad de San Luis 5700 (Argentina); Martinez, Luis D., E-mail: ldm@unsl.edu.ar [Área de Química Analítica, Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Ciudad de San Luis 5700 (Argentina); Instituto de Química de San Luis, INQUISAL, Centro Científico-Tecnológico de San Luis (CCT-San Luis), Consejo Nacional de Investigaciones Científicas y Universidad Nacional de San Luis, Ciudad de San Luis 5700 (Argentina)

    2015-05-22

    This article reviews 120 articles found in SCOPUS and specific Journal cites corresponding to the terms ‘preconcentration’; ‘speciation’; ‘vapor generation techniques’ and ‘atomic spectrometry techniques’ in the last 5 years. - Highlights: • Recent advances in vapor generation and atomic spectrometry were reviewed. • Species-specific preconcentration strategies after and before VG were discussed. • New preconcentration and speciation analysis were evaluated within this framework. - Abstract: We review recent progress in preconcentration strategies associated to vapor generation techniques coupled to atomic spectrometric (VGT-AS) for specific chemical species detection. This discussion focuses on the central role of different preconcentration approaches, both before and after VG process. The former was based on the classical solid phase and liquid–liquid extraction procedures which, aided by automation and miniaturization strategies, have strengthened the role of VGT-AS in several research fields including environmental, clinical, and others. We then examine some of the new vapor trapping strategies (atom-trapping, hydride trapping, cryotrapping) that entail improvements in selectivity through interference elimination, but also they allow reaching ultra-low detection limits for a large number of chemical species generated in conventional VG systems, including complete separation of several species of the same element. This review covers more than 100 bibliographic references from 2009 up to date, found in SCOPUS database and in individual searches in specific journals. We finally conclude by giving some outlook on future directions of this field.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-14

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

  14. Au nanorods modulated NIR fluorescence and singlet oxygen generation of water soluble dendritic zinc phthalocyanine.

    Science.gov (United States)

    Zhou, Xuefei; He, Xiaohong; Wei, Shiliang; Jia, Kun; Liu, Xiaobo

    2016-11-15

    A novel cyano-terminated zinc phthalocyanine (ZnPc-CN) exhibiting visible near infrared (vis-NIR) emitting around 690nm in N,N-dimethylformamide (DMF) solvent has been synthesized. Furthermore, the peripheral cyano groups of newly synthesized zinc phthalocyanine were hydrolyzed in strong basic solution, leading to water soluble carboxylated zinc phthalocyanine (ZnPc-COOH) with completely quenched fluorescence in aqueous solution. Interestingly, we found that the NIR fluorescence of aqueous ZnPc-COOH was dramatically recovered in the presence of gold nanorods (Au NR), which was due to the alternation of ZnPc-COOH molecules self-assembling via electrostatic interaction between cetyltrimethylammonium bromide (CTAB) on the surface of Au NR and peripheral carboxyl of ZnPc-COOH. In addition, ZnPc-COOH/Au NR conjugates demonstrated an improved singlet oxygen generation, which could be served as potential bioimaging probe and photosensitizer for photodynamic therapy.

  15. In vitro imaging of thyroid tissues using two-photon excited fluorescence and second harmonic generation.

    Science.gov (United States)

    Huang, Zufang; Li, Zuanfang; Chen, Rong; Lin, Juqiang; Li, Yongzeng; Li, Chao

    2010-08-01

    To evaluate the feasibility of two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) imaging to discriminate the normal, nodular goiter and papillary cancerous thyroid tissue. In total, 45 fresh thyroid specimens (normal, 15; nodular goiter, 12; and papillary cancerous, 18) from 31 subjects were directly imaged by the TPEF and SHG combination method. The microstructure of follicle and collagen structure in thyroid tissue were clearly identified, morphologic changes between normal, nodular goiter, and papillary cancerous thyroid tissue were well characterized by using two-photon excitation fluorescence. SHG imaging of the collagen matrix also revealed the differences between normal and abnormal. Our preliminary study suggests that the TPEF and SHG combination method might be a useful tool in revealing pathologic changes in thyroid tissue.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-02-15

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

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

    Science.gov (United States)

    Karagodova, Tamara Y.

    1996-03-01

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

  18. NUMERICAL SIMULATION OF ATOMIZATION RAINFALL AND THE GENERATED FLOW ON A SLOPE

    Institute of Scientific and Technical Information of China (English)

    LIU Shi-he; TAI Wei; FAN Min; LUO Qiu-shi

    2012-01-01

    This article studies the atomization rainfall and the generated flow on a slope by numerical simulations.The atomization rainfall is simulated by a unified model for splash droplets and a suspended mist,and the distribution of the diameter of splash rain drops is analyzed.The slope runoff generated by the atomization rainfall is simulated by a depth-averaged 2-D model,and the localization of the rainfall intensity in space is specially considered.The simulation results show that:(1) the median rain size of the atomization rainfall increases in the longitudinal direction at first,then monotonously decreases,and the maximum value is taken at the longitudinal position not in consistent with the position where the maximum rain intensity is taken.In the lateral direction the median rain size monotonously decreases,(2) since the atomization rainfall is distributed in a strongly localized area,it takes a longer time for its runoff yield to reach a steady state than that in the natural rainfall,the variation ranges of the water depth and the velocity in the longitudinal and lateral directions are larger than those in the natural rainfall.

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

    CERN Document Server

    Fescenko, Ilja

    2014-01-01

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

  20. Generation of molecular diffuse-band stimulated radiation through multiple excitation mechanism in potassium molecule-atom system

    Institute of Scientific and Technical Information of China (English)

    贾锁堂; 秦莉娟; 钱祖良; 王祖赓; 王钢; 周国生

    1997-01-01

    Population reduction effect generated in two-photon resonant excitation process of potassium atoms in a potassium molecule-atom system is theoretically investigated The obtained result is compared with the relevant experimental ones in the process of two-photon resonant excitation of potassium molecules and in the process of two-photon mixed excitation of potassium molecule-atoms.

  1. Generation of atomic Greenberger-Horne-Zeilinger states and cluster states through cavity-assisted interaction

    Institute of Scientific and Technical Information of China (English)

    Huang Xiu-Hua; Lin Xiu-Min; Lin Gong-Wei; Chen Zhi-Hua; Tang Yao-Xiang

    2008-01-01

    This paper proposes a scalable scheme to generate n-atom GHZ states and cluster states by using the basic building block, i.e., a weak coherent optical pulse |α) being reflected successively from a single-atom cavity. In the schemes,coherent state of light is used instead of single photon source, homodyne measurement on coherent light is done instead of single photon detection, and no need for individually addressing keeps the schemes easy to implement from the experimental point of view. The successful probabilities of our protocols approach unity in the ideal ease.

  2. Laser stabilization to an atomic transition using an optically generated dispersive lineshape

    CERN Document Server

    Queiroga, Fabiano; Mestre, Valdeci; Vidal, Itamar; de Silans, Thierry Passerat; Oriá, Marcos; Chevrollier, Martine

    2012-01-01

    We report on a simple and robust technique to generate a dispersive signal which serves as an error signal to electronically stabilize a monomode cw laser emitting around an atomic resonance. We explore nonlinear effects in the laser beam propagation through a resonant vapor by way of spatial filtering. The performance of this technique is validated by locking semiconductor lasers to the cesium and rubidiumD2 line and observing long-term reduction of the emission frequency drifts, making the laser well adapted for many atomic physics applications.

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

    Science.gov (United States)

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

  4. Protein Nano-Object Integrator (ProNOI for generating atomic style objects for molecular modeling

    Directory of Open Access Journals (Sweden)

    Smith Nicholas

    2012-12-01

    Full Text Available Abstract Background With the progress of nanotechnology, one frequently has to model biological macromolecules simultaneously with nano-objects. However, the atomic structures of the nano objects are typically not available or they are solid state entities. Because of that, the researchers have to investigate such nano systems by generating models of the nano objects in a manner that the existing software be able to carry the simulations. In addition, it should allow generating composite objects with complex shape by combining basic geometrical figures and embedding biological macromolecules within the system. Results Here we report the Protein Nano-Object Integrator (ProNOI which allows for generating atomic-style geometrical objects with user desired shape and dimensions. Unlimited number of objects can be created and combined with biological macromolecules in Protein Data Bank (PDB format file. Once the objects are generated, the users can use sliders to manipulate their shape, dimension and absolute position. In addition, the software offers the option to charge the objects with either specified surface or volumetric charge density and to model them with user-desired dielectric constants. According to the user preference, the biological macromolecule atoms can be assigned charges and radii according to four different force fields: Amber, Charmm, OPLS and PARSE. The biological macromolecules and the atomic-style objects are exported as a position, charge and radius (PQR file, or if a default dielectric constant distribution is not selected, it is exported as a position, charge, radius and epsilon (PQRE file. As illustration of the capabilities of the ProNOI, we created a composite object in a shape of a robot, aptly named the Clemson Robot, whose parts are charged with various volumetric charge densities and holds the barnase-barstar protein complex in its hand. Conclusions The Protein Nano-Object Integrator (ProNOI is a convenient tool for

  5. Protein Nano-Object Integrator (ProNOI) for generating atomic style objects for molecular modeling.

    Science.gov (United States)

    Smith, Nicholas; Campbell, Brandon; Li, Lin; Li, Chuan; Alexov, Emil

    2012-12-05

    With the progress of nanotechnology, one frequently has to model biological macromolecules simultaneously with nano-objects. However, the atomic structures of the nano objects are typically not available or they are solid state entities. Because of that, the researchers have to investigate such nano systems by generating models of the nano objects in a manner that the existing software be able to carry the simulations. In addition, it should allow generating composite objects with complex shape by combining basic geometrical figures and embedding biological macromolecules within the system. Here we report the Protein Nano-Object Integrator (ProNOI) which allows for generating atomic-style geometrical objects with user desired shape and dimensions. Unlimited number of objects can be created and combined with biological macromolecules in Protein Data Bank (PDB) format file. Once the objects are generated, the users can use sliders to manipulate their shape, dimension and absolute position. In addition, the software offers the option to charge the objects with either specified surface or volumetric charge density and to model them with user-desired dielectric constants. According to the user preference, the biological macromolecule atoms can be assigned charges and radii according to four different force fields: Amber, Charmm, OPLS and PARSE. The biological macromolecules and the atomic-style objects are exported as a position, charge and radius (PQR) file, or if a default dielectric constant distribution is not selected, it is exported as a position, charge, radius and epsilon (PQRE) file. As illustration of the capabilities of the ProNOI, we created a composite object in a shape of a robot, aptly named the Clemson Robot, whose parts are charged with various volumetric charge densities and holds the barnase-barstar protein complex in its hand. The Protein Nano-Object Integrator (ProNOI) is a convenient tool for generating atomic-style nano shapes in conjunction with

  6. Laser-induced fluorescence from N2(+) ions generated by a corona discharge in ambient air.

    Science.gov (United States)

    Konthasinghe, Kumarasiri; Fitzmorris, Kristin; Peiris, Manoj; Hopkins, Adam J; Petrak, Benjamin; Killinger, Dennis K; Muller, Andreas

    2015-09-01

    In this work, we present the measurement of laser-induced fluorescence from N2(+) ions via the B(2)Σu(+)-X(2)Σg(+) band system in the near-ultraviolet. The ions were generated continuously by a plasma glow discharge in low pressure N2 and by a corona discharge in ambient air. The fluorescence decay time was found to rapidly decrease with increasing pressure leading to an extrapolated decay rate of ≍10(10) s(-1) at atmospheric pressure. In spite of this quenching, we were able to observe laser induced fluorescence in ambient air by means of a time-gated spectral measurement. In the process of comparing the emission signal with that of N2 spontaneous Raman scattering, ion concentrations in ambient air of order 10(8-)10(10) cm(-3) were determined. With moderate increases in laser power and collection efficiency, ion concentrations of less than 10(6) cm(-3) may be measurable, potentially enabling applications in atmospheric standoff detection of ionizing radiation from hazardous radioactive sources.

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

    Science.gov (United States)

    Schultz, Danielle; Gwinn, Elisabeth G

    2012-06-11

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

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

    Institute of Scientific and Technical Information of China (English)

    刘燕芬

    2015-01-01

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

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

    DEFF Research Database (Denmark)

    Lu, Weifang; Ou, Yiyu; Jokubavicius, Valdas

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-06-01

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

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

    Science.gov (United States)

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

    2012-04-01

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

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

    Science.gov (United States)

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

    2016-07-01

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

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

    Science.gov (United States)

    Hoshi, Osamu; Ushiki, Tatsuo

    2014-01-01

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

  15. Generation of high-frequency combs locked to atomic resonances by quantum phase modulation

    CERN Document Server

    Liu, Zuoye; Cavaletto, Stefano M; Harman, Zoltán; Keitel, Christoph H; Pfeifer, Thomas

    2013-01-01

    A general mechanism for the generation of frequency combs referenced to atomic resonances is put forward. The mechanism is based on the periodic phase control of a quantum system's dipole response. We develop an analytic description of the comb spectral structure, depending on both the atomic and the phase-control properties. We further suggest an experimental implementation of our scheme: Generating a frequency comb in the soft-x-ray spectral region, which can be realized with currently available techniques and radiation sources. The universality of this mechanism allows the generalization of frequency-comb technology to arbitrary frequencies, including the hard-x-ray regime by using reference transitions in highly charged ions.

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

    Science.gov (United States)

    Jiang, C.; Carter, C.

    2014-12-01

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

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

    Science.gov (United States)

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

    2015-03-24

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

  18. Photoluminecsence and Generation of Golmium (Ho) Atoms in the Glassfiber and in the Cristall Media

    CERN Document Server

    Ogluzdin, Valeriy E

    2011-01-01

    The purpose of the given message - interpretation of the processes providing a photoluminescence and laser generation in spectral area 2000 nm at use as the active laser environment cristall or glass material, activated by an atomicholmium. Offered in article interpretation is based on use of the law of the conservation of energy, which attraction allows to reveal in an atomic holmium the transitions responsible for a photoluminecsence in specified area of a spectrum (2000 nm).

  19. Nonclassical Photon Pairs Generated from a Room-temperature Atomic Ensemble

    Institute of Scientific and Technical Information of China (English)

    JIANG Wei; HAN Chao; XUE Peng; DUAN L M; GUO G C

    2004-01-01

    @@ We report experimental generation of non-classically correlated photon pairs from collective emission in a room temperature atomic vapor cell.The nonclassical feature of the emission is demonstrated by observing a violation of the Cauchy-Schwarz inequality.Each pair of correlated photons are separated by a controllable time delay up to 2 microseconds.This experiment demonstrates an important step towards the realization of the Duan-Lukin-Cirac-Zoller scheme for scalable long-distance quantum communication.

  20. Two-color ghost interference with photon pairs generated in hot atoms

    Directory of Open Access Journals (Sweden)

    Dong-Sheng Ding

    2012-09-01

    Full Text Available We report on an experimental observation of a two-photon ghost interference experiment. A distinguishing feature of our experiment is that the photons are generated via a non-degenerated spontaneous four-wave mixing process in a hot atomic ensemble; therefore the photon has narrow bandwidth. Besides, there is a large difference in frequency between two photons in a pair. Our works may be important to achieve more secure, large transmission capacity long-distance quantum communication.

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

    Directory of Open Access Journals (Sweden)

    K. Kita

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

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

    Science.gov (United States)

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

    2001-08-01

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

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

    Indian Academy of Sciences (India)

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

    2010-12-01

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

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

    NARCIS (Netherlands)

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

    1975-01-01

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

  5. Ultratrace determination of lead by hydride generation in-atomizer trapping atomic absorption spectrometry: Optimization of plumbane generation and analyte preconcentration in a quartz trap-and-atomizer device

    Energy Technology Data Exchange (ETDEWEB)

    Kratzer, Jan, E-mail: jkratzer@biomed.cas.cz

    2012-05-15

    A compact trap-and-atomizer device and a preconcentration procedure based on hydride trapping in excess of oxygen over hydrogen in the collection step, both constructed and developed previously in our laboratory, were employed to optimize plumbane trapping in this device and to develop a routine method for ultratrace lead determination subsequently. The inherent advantage of this preconcentration approach is that 100% preconcentration efficiency for lead is reached in this device which has never been reported before using quartz or metal traps. Plumbane is completely retained in the trap-and-atomizer device at 290 Degree-Sign C in oxygen-rich atmosphere and trapped species are subsequently volatilized at 830 Degree-Sign C in hydrogen-rich atmosphere. Effect of relevant experimental parameters on plumbane trapping and lead volatilization are discussed, and possible trapping mechanisms are hypothesized. Plumbane trapping in the trap-and-atomizer device can be routinely used for lead determination at ultratrace levels reaching a detection limit of 0.21 ng ml{sup -1} Pb (30 s preconcentration, sample volume 2 ml). Further improvement of the detection limit is feasible by reducing the blank signal and increasing the trapping time. - Highlights: Black-Right-Pointing-Pointer In-atomizer trapping HG-AAS was optimized for Pb. Black-Right-Pointing-Pointer A compact quartz trap-and-atomizer device was employed. Black-Right-Pointing-Pointer Generation, preconcentration and atomization steps were investigated in detail. Black-Right-Pointing-Pointer 100% preconcentration efficiency for lead was reached. Black-Right-Pointing-Pointer Routine analytical method was developed for Pb determination (LOD of 0.2 ng ml{sup -1} Pb).

  6. New generation ICG-based contrast agents for ultrasound-switchable fluorescence imaging

    Science.gov (United States)

    Yu, Shuai; Cheng, Bingbing; Yao, Tingfeng; Xu, Cancan; Nguyen, Kytai T.; Hong, Yi; Yuan, Baohong

    2016-10-01

    Recently, we developed a new technology, ultrasound-switchable fluorescence (USF), for high-resolution imaging in centimeter-deep tissues via fluorescence contrast. The success of USF imaging highly relies on excellent contrast agents. ICG-encapsulated poly(N-isopropylacrylamide) nanoparticles (ICG-NPs) are one of the families of the most successful near-infrared (NIR) USF contrast agents. However, the first-generation ICG-NPs have a short shelf life (6 months). In addition, we have conjugated hydroxyl or carboxyl function groups on the ICG-NPs for future molecular targeting. Finally, we have demonstrated the effect of temperature-switching threshold (Tth) and the background temperature (TBG) on the quality of USF images. We estimated that the Tth of the ICG-NPs should be controlled at ~38–40 °C (slightly above the body temperature of 37 °C) for future in vivo USF imaging. Addressing these challenges further reduces the application barriers of USF imaging.

  7. Caged fluorescent haptens reveal the generation of cryptic epitopes in allergic contact dermatitis.

    Science.gov (United States)

    Simonsson, Carl; Andersson, Sofia I; Stenfeldt, Anna-Lena; Bergström, Jörgen; Bauer, Brigitte; Jonsson, Charlotte A; Ericson, Marica B; Broo, Kerstin S

    2011-07-01

    Allergic contact dermatitis (ACD) is the most prevalent form of human immunotoxicity. It is caused by skin exposure to haptens, i.e., protein-reactive, low-molecular-weight chemical compounds, which form hapten-protein complexes (HPCs) in the skin, triggering the immune system. These immunogenic HPCs are elusive. In this study a series of thiol-reactive caged fluorescent haptens, i.e., bromobimanes, were deployed in combination with two-photon fluorescence microscopy, immunohistochemistry, and proteomics to identify possible hapten targets in proteins in human skin. Key targets found were the basal keratinocytes and the keratins K5 and K14. Particularly, cysteine 54 of K5 was found to be haptenated by the bromobimanes. In addition, elevated levels of anti-keratin antibodies were found in the sera of mice exposed to bromobimanes in vivo. The results indicate a general mechanism in which thiol-reactive haptens generate cryptic epitopes normally concealed from the immune system. In addition, keratinocytes and keratin seem to have an important role in the mechanism behind ACD, which is a subject for further investigations.

  8. New generation ICG-based contrast agents for ultrasound-switchable fluorescence imaging

    Science.gov (United States)

    Yu, Shuai; Cheng, Bingbing; Yao, Tingfeng; Xu, Cancan; Nguyen, Kytai T.; Hong, Yi; Yuan, Baohong

    2016-01-01

    Recently, we developed a new technology, ultrasound-switchable fluorescence (USF), for high-resolution imaging in centimeter-deep tissues via fluorescence contrast. The success of USF imaging highly relies on excellent contrast agents. ICG-encapsulated poly(N-isopropylacrylamide) nanoparticles (ICG-NPs) are one of the families of the most successful near-infrared (NIR) USF contrast agents. However, the first-generation ICG-NPs have a short shelf life (6 months). In addition, we have conjugated hydroxyl or carboxyl function groups on the ICG-NPs for future molecular targeting. Finally, we have demonstrated the effect of temperature-switching threshold (Tth) and the background temperature (TBG) on the quality of USF images. We estimated that the Tth of the ICG-NPs should be controlled at ~38–40 °C (slightly above the body temperature of 37 °C) for future in vivo USF imaging. Addressing these challenges further reduces the application barriers of USF imaging. PMID:27775014

  9. Generation of a fluorescent transgenic zebrafish for detection of environmental estrogens

    Energy Technology Data Exchange (ETDEWEB)

    Chen Hao; Hu Jingying; Yang Jian; Wang Yuexiang; Xu Hui; Jiang Qiu; Gong Yuebo; Gu Yinliang [Department of Molecular Genetics, Shanghai Medical School and Key Laboratory of Molecular Medicine, Ministry of Education, Fudan University, 200032 (China); Song Houyan, E-mail: hysong@shmu.edu.cn [Department of Molecular Genetics, Shanghai Medical School and Key Laboratory of Molecular Medicine, Ministry of Education, Fudan University, 200032 (China)

    2010-01-21

    To establish a novel in vivo test system for rapid detection of environmental estrogens, an ere-zvtg1: gfp transgenic zebrafish line has been generated. In this transgenic line, under control conditions, GFP was exclusively expressed in the liver of mature adult female fish. Male and larval transgenic fish did not express GFP but could be induced to express GFP in the liver after exposure to 17-{alpha}-ethynylestradiol (EE{sub 2}). Concurrent accumulation of zvtg1 and gfp mRNAs in embryos and larvae after EE{sub 2} exposure was observed, which indicated that the expression of gfp transgene was driven by the zvtg1 promoter. Green fluorescence was first observed in the liver at 53, 74, 100 or 131 h post-fertilization (hpf) after exposure to 100, 10, 1 or 0.1 ng/L EE{sub 2} from 1 to 2 cell stage, respectively. As for mature male transgenic zebrafish, green fluorescence was observed after exposure to 100, 10, 1 or 0.1 ng/L EE{sub 2} for 2, 3, 4 or 7 days, respectively; as for mature female, fluorescence was increased after exposure to relatively high concentrations of EE{sub 2} (10 and 100 ng/L). Green fluorescence in the liver was increased with prolonging of exposure time and was repeatedly induced after removal and re-addition of EE{sub 2}. We also demonstrated that GFP expression could be induced by other estrogenic compounds, including {beta}-estradiol (E{sub 2}, 0.1 {mu}g/L), cadmium chloride (CdCl{sub 2}, 10 {mu}g/L), zearalenone (50 {mu}g/L), estriol (E{sub 3}, 1 {mu}g/L), diethylstilbestrol (DES, 50 ng/L) bisphenol A (BPA, 1 mg/L) but not by weakly estrogenic compounds such as nonylphenol (NP, up to 10 mg/L), or non-estrogenic steroid hormones such as progesterone (up to 100 mg/L) and 17-hydroxysteroid (up to 50 mg/L). These data suggest the transgenic zebrafish is sensitive and specific for detection of estrogenic compounds. Because the observed-effect concentrations are as low as those of environment and the observed-effect exposure times are very short

  10. Generation of fluorescent CdSe nanocrystals by short-pulse laser fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Zholudov, Yu. T., E-mail: yurets-z@rambler.ru [Kharkiv National University of Radioelectronics (Ukraine); Sajti, C. L., E-mail: l.sajti@lzh.de [Laser Zentrum Hannover e.V. (Germany); Slipchenko, N. N. [Kharkiv National University of Radioelectronics (Ukraine); Chichkov, B. N. [Laser Zentrum Hannover e.V. (Germany)

    2015-12-15

    A simple liquid-phase laser fragmentation approach, resulting in the rapid transformation of CdSe microcrystals into colloidal quantum dots (QDs), is presented. Laser fragmentation is achieved by irradiating a CdSe suspension in dimethylformamide with intense infrared, picosecond laser pulses followed by surface passivation with oleylamine or different types of phosphines. The generated QDs reveal perfect colloidal stability preventing agglomeration and precipitation, and show characteristic QD absorption and fluorescence characteristics, whereas their emission properties strongly depend on the surface states and applied capping ligands. These QDs show distinct photoemission under 405-nm single-photon and 800-nm multi-photon excitations in the 560- to 610-nm spectral region corresponding to the QDs size of about 1.5–2 nm in diameter which is confirmed by transmission electron microscopy.

  11. SPE speciation of inorganic arsenic in rice followed by hydride-generation atomic fluorescence spectrometric quantification

    Science.gov (United States)

    Due to high toxicity, inorganic arsenics (iAs) are the focus of monitoring effort worldwide. In this work, extraction was performed by microwave-assisted digestion in HCl-H2O2, during which AsIII was oxidized to AsV. AsV was separated from organoarsenic species using silica-based SAX cartridge and r...

  12. 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.

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

    Science.gov (United States)

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

    2011-04-27

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

  15. Probes for 4th generation constituents of dark atoms in Higgs boson studies at the LHC

    CERN Document Server

    Khlopov, M Yu

    2014-01-01

    The nonbaryonic dark matter of the Universe can consist of new stable charged species, bound in heavy neutral "atoms" by ordinary Coulomb interaction. Stable $\\bar U$ (anti-$U$)quarks of 4th generation, bound in stable colorless ($\\bar U \\bar U \\bar U $) clusters, are captured by the primordial helium, produced in Big Bang Nucleosynthesis, thus forming neutral "atoms" of O-helium (OHe), a specific nuclear interacting dark matter that can provide solution for the puzzles of direct dark matter searches. However, the existence of the 4th generation quarks and leptons should influence the production and decay rates of Higgs boson and is ruled out by the experimental results of the Higgs boson searches at the LHC, if the Higgs boson coupling to 4th generation fermions with is not suppressed. Here we argue that the difference between the three known quark-lepton families and the 4th family can naturally lead to suppression of this coupling, relating the accelerator test for such a composite dark matter scenario to ...

  16. Hot-Wire generated atomic hydrogen and its impact on thermal ALD in $TiCl_4/NH_3$ system

    NARCIS (Netherlands)

    Van Bui, H.; Kovalgin, A.Y.; Aarnink, A.A.I.; Wolters, R.A.M.

    2013-01-01

    We present the generation of atomic hydrogen made by the dissociation of molecular hydrogen upon collision with a tungsten (W) filament kept at a high temperature (T ≈ 1600–1900◦C). We demonstrate the ability to create atomic hydrogen and to introduce it in short pulses in experiments on etching of

  17. A solvable operator motion equation of an excited-atom coupled leaky cavity in single-photon generation

    Institute of Scientific and Technical Information of China (English)

    Chai Jin-Hua; Han Zheng-Fu

    2009-01-01

    A model for an excited-atom coupled leaky cavity in single-photon generation is proposed based on universal modes. Solvable motion equations of the atomic operators are obtained under the single-photon condition by adopting the Lorentzian line type of the universal modes.

  18. Harmonic generation by atomic and nanoparticle precursors in a ZnS laser ablation plasma

    Science.gov (United States)

    Oujja, M.; Lopez-Quintas, I.; Benítez-Cañete, A.; de Nalda, R.; Castillejo, M.

    2017-01-01

    Harmonic generation of a driving laser propagating across a laser ablation plasma serves for the diagnosis of multicomponent plumes. Here we study the contribution of atomic and nanoparticle precursors to the generation of coherent ultraviolet and vacuum ultraviolet light as low-order harmonics of the fundamental emission (1064 nm) of a Q-switched Nd:YAG laser in a nanosecond infrared ZnS laser ablation plasma. Odd harmonics from the 3rd up to the 9th order (118.2 nm) have been observed with distinct temporal and spatial characteristics which were determined by varying the delay between the ablation and driving nanosecond pulses and by spatially scanning the plasma with the focused driving beam propagating parallel to the target. At short distances from the target surface (≤1 mm), the harmonic intensity displays two temporal components peaked at around 250 ns and 10 μs. While the early component dies off quickly with increasing harmonic order and vanishes for the 9th order, the late component is notably intense for the 7th harmonic and is still clearly visible for the 9th. Spectral analysis of spontaneous plume emissions help to assign the origin of the two components. While the early plasma component is mainly constituted by neutral Zn atoms, the late component is mostly due to nanoparticles, which upon interaction with the driving laser are subject to breakup and ionization. With the aid of calculations of the phase matching integrals within the perturbative model of optical harmonic generation, these results illustrate how atom and nanoparticle populations, with differing temporal and spatial distributions within the ablation plasma, contribute to the nonlinear medium.

  19. Iodine Determination by Microwave Plasma Torch Atomic Emission Spectrometer Coupled with Online Preconcentration Vapor Generation Technique

    Institute of Scientific and Technical Information of China (English)

    FEI Yan-qun; LUO Gui-min; FENG Guo-dong; CHEN Huan-wen; FEI Qiang; HUAN Yan-fu; JIN Qin-han

    2008-01-01

    This article focuses on iodine determination by microwave plasma torch atomic emission spectrometry (MPT-AES) coupled with online preconcentration vapor generation method.A new desolvation device,multistrand Nation dryer,was used as the substitute for condenser desolvation system.Some experimental conditions,such as preconcentration time,acidity of sample solution,rinsing solution acidity and dynamic linear range were investigated and optimized.The new desolvation system eliminates the problem of decreasing emission intensity of I(I) 206.238 nm line with the increase of working time on a conventional condenser desolvation system,thus greatly improving the reproducibility.

  20. Atom-Generated Spatial Multi-Mode Structure of Squeezed Light

    CERN Document Server

    Zhang, Mi; Xiao, Zhihao; Dowling, Jonathan P; Novikova, Irina; Mikhailov, Eugeniy E

    2015-01-01

    We generate a squeezed vacuum field via an interaction between a laser beam and an atomic ensemble. A measurement of the quantum noise of a spatially modified squeezed field is conducted. We find the noise suppression to be greatly affected by the transverse profile of the spatial mask and its position along the propagation direction. We have developed a multimode model to describe the mode structure of the light fields which qualitatively explains the quadrature noise behavior in terms of higher-order Laguerre-Gauss modes.

  1. Generating topological optical flux lattices for ultracold atoms by modulated Raman and radio-frequency couplings

    Science.gov (United States)

    Yu, Jinlong; Xu, Zhi-Fang; You, Li

    2017-01-01

    We propose a scheme to dynamically generate optical flux lattices with nontrivial band topology using amplitude-modulated Raman lasers and radio-frequency (rf) magnetic fields. By tuning the strength of Raman and rf fields, three distinct phases are realized at unit filling for a unit cell. Respectively, these three phases correspond to normal insulator, topological Chern insulator, and semimetal. Nearly nondispersive bands are found to appear in the topological phase, which promises opportunities for investigating strongly correlated quantum states within a simple cold-atom setup. The validity of our proposal is confirmed by comparing the Floquet quasienergies from the evolution operator with the spectrum of the effective Hamiltonian.

  2. Laboratory-generated primary marine aerosol via bubble-bursting and atomization

    Directory of Open Access Journals (Sweden)

    E. Fuentes

    2009-09-01

    supersaturation was obtained for the atomization-generated particles. The results of this work show that the aerosol generation mechanism affects the particles organic enrichment, thus the behaviour of the produced aerosols strongly depends on the laboratory aerosol generator employed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-05-15

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

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

    Science.gov (United States)

    Conway, Jim; Gogna, Gurusharan; Daniels, Stephen

    2016-09-01

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

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

    Science.gov (United States)

    Norlén, L; Plasencia, I; Bagatolli, L

    2008-12-01

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

  6. Increasing efficiency of two-photon excited fluorescence and second harmonic generation using ultrashort pulses

    Science.gov (United States)

    Tang, Shuo; Krasieva, Tatiana B.; Chen, Zhongping; Tempea, Gabriel; Tromberg, Bruce J.

    2006-02-01

    Multiphoton microscopy (MPM) has become an important tool for high-resolution and non-invasive imaging in biological tissues. However, the efficiencies of two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) are relatively low because of their nonlinear nature. Therefore, it is critical to optimize laser parameters for most efficient excitation of MPM. Reducing the pulse duration can increase the peak intensity of excitation and thus potentially increase the excitation efficiency. In this paper, a multiphoton microscopy system using a 12 fs Ti:Sapphire laser is reported. With adjustable dispersion pre-compensation, the pulse duration at the sample location can be varied from 400 fs to sub-20 fs. The efficiencies of TPEF and SHG are studied for the various pulse durations, respectively. Both TPEF and SHG are found to increase proportionally to the inverse of the pulse duration for the entire tested range. To transmit most of the SHG and TPEF signals, the spectral transmission widow of the detection optics needs to be carefully considered. Limitation from phase-matching in SHG generation is not significant because the effective interaction length for SHG is less than 10 μm at the focal depth of the objectives. These results are important in improving MPM excitation efficiency using ultrashort pulses. MPM images from human artery wall are also demonstrated.

  7. Atomization off thin water films generated by high-frequency substrate wave vibrations.

    Science.gov (United States)

    Collins, David J; Manor, Ofer; Winkler, Andreas; Schmidt, Hagen; Friend, James R; Yeo, Leslie Y

    2012-11-01

    Generating aerosol droplets via the atomization of thin aqueous films with high frequency surface acoustic waves (SAWs) offers several advantages over existing nebulization methods, particularly for pulmonary drug delivery, offering droplet sizes in the 1-5-μm range ideal for effective pulmonary therapy. Nevertheless, the physics underlying SAW atomization is not well understood, especially in the context of thin liquid film formation and spreading and how this affects the aerosol production. Here, we demonstrate that the film geometry, governed primarily by the applied power and frequency of the SAW, indeed plays a crucial role in the atomization process and, in particular, the size of the atomized droplets. In contrast to the continuous spreading of low surface energy liquids atop similar platforms, high surface energy liquids such as water, in the present case, are found to undergo transient spreading due to the SAW to form a quasisteady film whose height is determined by self-selection of the energy minimum state associated with the acoustic resonance in the film and whose length arises from a competition between acoustic streaming and capillary effects. This is elucidated from a fundamental model for the thin film spreading behavior under SAW excitation, from which we show good agreement between the experimentally measured and theoretically predicted droplet dimension, both of which consistently indicate a linear relationship between the droplet diameter and the mechanical power coupled into the liquid by the SAW (the latter captured by an acoustic Weber number to the two thirds power, and the reciprocal of the SAW frequency).

  8. Hydroxyl radical electrochemically generated with water as the complete atom source and its environmental application

    Institute of Scientific and Technical Information of China (English)

    CONG YanQing; WU ZuCheng; LI YuQiong

    2007-01-01

    The most reactive hydroxyl radical(·OH) was generated by electrochemical approach with safe water as the complete atom source. The direct evidence for ·OH formation was obtained by electron spin resonance method. The powerful ·OH electrochemically generated could effectively degrade organic pollutants and reduce the toxicity of wastewater. Electrochemical disinfection by ·OH was considerably efficient even without the aid of active chlorine. Bacteria inactivation of 99.99% was achieved for contact time of 30 min and current density of 5 mA.cm-2. In comparison with active chlorine, ·OH is rather attractive as a promising environmentally benign disinfectant and opens a new route for microbial inactivation.

  9. Generation of uniform fine droplets under spindle mode in electrohydrodynamic atomization

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M.C.; Lee, S.Y.; Kim, S.S.; Kim, Y.D. [Korea Advanced Institute of Science and Technology, Taejeon (Korea)

    2001-07-01

    A series of experiments were conducted to generate fine liquid(water) drops through the electrohydrodynamic atomization process. The atomization mode depended on flow rate and DC voltage input. For water, having electric conductivity larger than 10{sup -7} S/m, the spindle mode turned out to be the only mode to generate uniform-size drops within the range of 30-450 microns that have wide applications. Within this mode, both the uniformity and the fineness of drops were improved at an optimum voltage input for a given flow rate. This optimum voltage increased with increasing of the liquid flow rate. Another important parameter considered was the nozzle material with different electric conductivity and liquid wettability. A stainless-steel nozzle (the material with high electric conductivity and high liquid wettability) and a silica nozzle (the electrically non-conducting material with low liquid wettability) were tested and compared; and more uniform drops could be obtained with the silica nozzle. (author). 21 refs., 12 figs., 3 tabs.

  10. Fast generation of three-dimensional entanglement between two spatially separated atoms via invariant-based shortcut

    Science.gov (United States)

    Wu, Jin-Lei; Song, Chong; Ji, Xin; Zhang, Shou

    2016-10-01

    A scheme is proposed for the fast generation of three-dimensional entanglement between two atoms trapped in two cavities connected by a fiber via invariant-based shortcut to adiabatic passage. With the help of quantum Zeno dynamics, the technique of invariant-based shortcut to adiabatic passage is applied for the generation of two-atom three-dimensional entanglement. The numerical simulation results show that, within a short time, the scheme has a high fidelity and is robust against the decoherence caused by the atomic spontaneous emission, photon leakage, and the variations in the parameters selected. Moreover, the scheme may be possible to be implemented with the current experimental technology.

  11. Green and ultraviolet pulse generation with a compact, fiber laser, chirped-pulse amplification system for aerosol fluorescence measurements

    Science.gov (United States)

    Lou, Janet W.; Currie, Marc; Sivaprakasam, Vasanthi; Eversole, Jay D.

    2010-10-01

    We use a compact chirped-pulse amplified system to harmonically generate ultrashort pulses for aerosol fluorescence measurements. The seed laser is a compact, all-normal dispersion, mode-locked Yb-doped fiber laser with a 1050 nm center wavelength operating at 41 MHz. Average powers of more than 1.2 W at 525 nm and 350 mW at 262 nm are generated with biofluorescence measurements as it allows faster sampling rates as well as the higher peak powers as compared to previously demonstrated Q-switched systems while maintaining a pulse period that is longer than the typical fluorescence lifetimes. Thus, the fluorescence excitation can be considered to be quasicontinuous and requires no external synchronization and triggering.

  12. Heat generation and light scattering of green fluorescent protein-like pigments in coral tissue.

    Science.gov (United States)

    Lyndby, Niclas H; Kühl, Michael; Wangpraseurt, Daniel

    2016-05-26

    Green fluorescent protein (GFP)-like pigments have been proposed to have beneficial effects on coral photobiology. Here, we investigated the relationships between green fluorescence, coral heating and tissue optics for the massive coral Dipsastraea sp. (previously Favia sp.). We used microsensors to measure tissue scalar irradiance and temperature along with hyperspectral imaging and combined imaging of variable chlorophyll fluorescence and green fluorescence. Green fluorescence correlated positively with coral heating and scalar irradiance enhancement at the tissue surface. Coral tissue heating saturated for maximal levels of green fluorescence. The action spectrum of coral surface heating revealed that heating was highest under red (peaking at 680 nm) irradiance. Scalar irradiance enhancement in coral tissue was highest when illuminated with blue light, but up to 62% (for the case of highest green fluorescence) of this photon enhancement was due to green fluorescence emission. We suggest that GFP-like pigments scatter the incident radiation, which enhances light absorption and heating of the coral. However, heating saturates, because intense light scattering reduces the vertical penetration depth through the tissue eventually leading to reduced light absorption at high fluorescent pigment density. We conclude that fluorescent pigments can have a central role in modulating coral light absorption and heating.

  13. Observation of hydrocarbon generation and migration of highly-matured carbonates by means of laser-induced fluorescence microscopy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Some important information on hydrocarbon generation, inclusion and migration in highly-matured carbonates of lower Palaeozoic age from the Ordos Basin and Tarim Basin hasbeen analyzed by a newly-combined laser-induced fluorescence microscope (LFM) designed by our laboratory. The following information has been obtained from the lower Ordovician lamellar carbonates with equivalent vitrinite reflectance (Ro) as high as 1.6%-1.7% and residual TOC of 0.14%-0.35% from the Ordos Basin: wide occurrences of oil and source macerals with strong fluorescence, including G. Prisca alginite, lamalginite, telalginite and algae-detrinite; fluorescing asphalt among mineral crystals; some groundmass and spheroid-like reservoir bitumen with high maturation levels in the pores of dolomites. Various kinds of fluorescing organic inclusions and asphalt have been found in the carbonates, calcareous shales and silt-shales with high maturation levels from the Cambrian-Ordovician strata in the Tarim Basin. All this helps us find and evaluate significant and excellent source rocks for large-and middle-scale gas fields. The net and micro-net systems for hydrocarbon generation, expulsion and migration in carbonates have been revealed by the highly-powered laser-induced fluorescence microscopy.

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-06-25

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

  16. Enhanced harmonic generation and wave-mixing via two-color multiphoton excitation of atoms/molecules

    CERN Document Server

    Avetissian, H K; Mkrtchian, G F

    2016-01-01

    We consider harmonics generation and wave-mixing by two-color multi photon resonant excitation of three-level atoms/molecules in strong laser fields. The coherent part of the spectra corresponding to multicolor harmonics generation is investigated. The obtained analytical results on the basis of generalized rotating wave approximation are in a good agreement with numerical calculations. The results applied to the hydrogen atom and homonuclear diatomic molecular ion show that one can achieve efficient generation of moderately high multicolor harmonics via multiphoton resonant excitation by appropriate laser pulses.

  17. Directed evolution methods for improving polypeptide folding and solubility and superfolder fluorescent proteins generated thereby

    Science.gov (United States)

    Waldo, Geoffrey S.

    2007-09-18

    The current invention provides methods of improving folding of polypeptides using a poorly folding domain as a component of a fusion protein comprising the poorly folding domain and a polypeptide of interest to be improved. The invention also provides novel green fluorescent proteins (GFPs) and red fluorescent proteins that have enhanced folding properties.

  18. Size Effects on Surface Elastic Waves in a Semi-Infinite Medium with Atomic Defect Generation

    Directory of Open Access Journals (Sweden)

    F. Mirzade

    2013-01-01

    Full Text Available The paper investigates small-scale effects on the Rayleigh-type surface wave propagation in an isotopic elastic half-space upon laser irradiation. Based on Eringen’s theory of nonlocal continuum mechanics, the basic equations of wave motion and laser-induced atomic defect dynamics are derived. Dispersion equation that governs the Rayleigh surface waves in the considered medium is derived and analyzed. Explicit expressions for phase velocity and attenuation (amplification coefficients which characterize surface waves are obtained. It is shown that if the generation rate is above the critical value, due to concentration-elastic instability, nanometer sized ordered concentration-strain structures on the surface or volume of solids arise. The spatial scale of these structures is proportional to the characteristic length of defect-atom interaction and increases with the increase of the temperature of the medium. The critical value of the pump parameter is directly proportional to recombination rate and inversely proportional to deformational potentials of defects.

  19. Learning a generative syntax from transparent syntactic atoms in the linguistic input.

    Science.gov (United States)

    Ninio, Anat

    2014-11-01

    We examined parents' two-word utterances expressing core syntactic relations in order to test the hypothesis that they may enable children to derive the atoms of hierarchical syntax, namely, the asymmetrical Merge/Dependency relation between pairs of words, and, in addition, to identify variables serving generative syntactic rules. Using a large English-language parental corpus, we located all two-word utterances containing a verb and its subject, object, or indirect object. Analysis showed that parental two-word sentences contain transparent information on the binary dependency/merge relation responsible for syntactic connectivity. The syntactic atoms modelled in the two-word input contain natural variables for dependents, making generalization to other contexts an immediate possibility. In a second study, a large sample of children were found to use the same verbs in the great majority of their early sentences expressing the same core grammatical relations. The results support a learning model according to which children learn the basics of syntax from parental two-word sentences.

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

    Institute of Scientific and Technical Information of China (English)

    谢倩

    2015-01-01

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

  1. Multipartite entangled spatial modes of ultracold atoms generated and controlled by quantum measurement.

    Science.gov (United States)

    Elliott, T J; Kozlowski, W; Caballero-Benitez, S F; Mekhov, I B

    2015-03-20

    We show that the effect of measurement backaction results in the generation of multiple many-body spatial modes of ultracold atoms trapped in an optical lattice, when scattered light is detected. The multipartite mode entanglement properties and their nontrivial spatial overlap can be varied by tuning the optical geometry in a single setup. This can be used to engineer quantum states and dynamics of matter fields. We provide examples of multimode generalizations of parametric down-conversion, Dicke, and other states; investigate the entanglement properties of such states; and show how they can be transformed into a class of generalized squeezed states. Furthermore, we propose how these modes can be used to detect and measure entanglement in quantum gases.

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

    National Research Council Canada - National Science Library

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2005-05-01

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

  4. Atmospheric plasma generates oxygen atoms as oxidizing species in aqueous solutions

    Science.gov (United States)

    Mokhtar Hefny, Mohamed; Pattyn, Cedric; Lukes, Petr; Benedikt, Jan

    2016-10-01

    A remote microscale atmospheric pressure plasma jet (µAPPJ) with He, He/H2O, He/O2, and He/O2/H2O gas mixtures was used to study the transport of reactive species from the gas phase into the liquid and the following aqueous phase chemistry. The effects induced by the µAPPJ in water were quantitatively studied using phenol as a chemical probe and by measuring H2O2 concentration and pH values. These results were combined with the analysis of the absolute densities of the reactive species and the modeling of convective/diffusion transport and recombination reactions in the effluent of the plasma jet. Additionally, modified plasma jets were used to show that the role of emitted photons in aqueous chemistry is negligible for these plasma sources. The fastest phenol degradation was measured for the He/O2 plasma, followed by He/H2O, He/O2/H2O, and He plasmas. The modeled quantitative flux of O atoms into the liquid in the He/O2 plasma case was highly comparable with the phenol degradation rate and showed a very high transfer efficiency of reactive species from the plasma into the liquid, where more than half of the O atoms leaving the jet nozzle entered the liquid. The results indicate that the high oxidative effect of He/O2 plasma was primarily due to solvated O atoms, whereas OH radicals dominated the oxidative effects induced in water by plasmas with other gas mixtures. These findings help to understand, in a quantitative way, the complex interaction of cold atmospheric plasmas with aqueous solutions and will allow a better understanding of the interaction of these plasmas with water or buffered solutions containing biological macromolecules, microorganisms, or even eukaryotic cells. Additionally, the µAPPJ He/O2 plasma source seems to be an ideal tool for the generation of O atoms in aqueous solutions for any future studies of their reactivity.

  5. Generation of long-living entanglement between two distant three-level atoms in non-Markovian environments.

    Science.gov (United States)

    Li, Chuang; Yang, Sen; Song, Jie; Xia, Yan; Ding, Weiqiang

    2017-05-15

    In this paper, a scheme for the generation of long-living entanglement between two distant Λ-type three-level atoms separately trapped in two dissipative cavities is proposed. In this scheme, two dissipative cavities are coupled to their own non-Markovian environments and two three-level atoms are driven by the classical fields. The entangled state between the two atoms is produced by performing Bell state measurement (BSM) on photons leaving the dissipative cavities. Using the time-dependent Schördinger equation, we obtain the analytical results for the evolution of the entanglement. It is revealed that, by manipulating the detunings of classical field, the long-living stationary entanglement between two atoms can be generated in the presence of dissipation.

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

    Science.gov (United States)

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

    2016-02-16

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

  7. 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}.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-04

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

  9. Determination of arsenic in a nickel alloy by flow injection hydride generation atomic absorption spectrometry

    Science.gov (United States)

    Hanna, C. P.; Tyson, J. F.; Offley, S. G.

    1992-08-01

    The development of a method for the direct determination of trace arsenic quantities in nickel alloy digests, by flow injection hydride generation atomic absorption spectrometry, is described. An optimization study of the manifold and chemical parameters produced system performance, in terms of tolerance of the nickel matrix and sensitivity, such that matrix removal and pre-reduction of As(V) to As (III) prior to arsine generation were eliminated. Full recovery of the As(V) signal from a solution containing 5 ng ml -1 in the presence of 60 μg ml -1 nickel was obtained. Validation of the method was achieved by analyzing a British Chemical Standard (BCS) Certified Reference Material (CRM) #346 IN nickel alloy containing arsenic at a concentration of 50 μg g -1. Following dissolution in nitric and hydrofluoric acids by a microwave assisted procedure, the only subsequent preparation required was dilution by the appropriate factor. Up to 60 injections h -1 may be made, with a detection limit of 0.5 ng ml -1 arsenic (250 pg absolute) as As(V) in a 500 μl sample. The peak height characteristic concentration is 0.46 ng ml -1, with a relative standard deviation of 3.5% for a 10 ng ml -1 As(V) standard ( n = 6).

  10. Next Generation of Advanced Laser Fluorescence Technology for Characterization of Natural Aquatic Environments

    Science.gov (United States)

    2011-09-30

    The project research addresses our long-term goal to develop an analytical suite of the Advanced Laser Fluorescence (ALF) methods and instruments to...sucessfully tested. It provides the accuracy of CC fluorescnce measurments comparable to the accuracy of commonly accepted preparatory methods , such HPLC...Plankton Reseach (Chekalyuk et al. 2011). Task 2 Development of Aquatic Laser Fluorescence Analyzer (ALFA). The ALFA instrument development is

  11. Near infrared fluorescent biliproteins generated from bacteriophytochrome AphB of Nostoc sp. PCC 7120.

    Science.gov (United States)

    Yuan, Che; Li, Hui-Zhen; Tang, Kun; Gärtner, Wolfgang; Scheer, Hugo; Zhou, Ming; Zhao, Kai-Hong

    2016-04-01

    The genome of the cyanobacterium Nostoc sp. PCC 7120 encodes a large number of putative bacteriophytochrome and cyanobacteriochrome photoreceptors that, due to their long-wavelength absorption and fluorescence emission, might serve as fluorescent tags in intracellular investigations. We show that the PAS-GAF domain of the bacteriophytochrome, AphB, binds biliverdin covalently and exhibits, besides its reversible photochemistry, a moderate fluorescence in the near infrared (NIR) spectral region. It was selected for further increasing the brightness while retaining the NIR fluorescence. In the first step, amino acids assumed to improve fluorescence were selectively mutated. The resulting variants were then subjected to several rounds of random mutagenesis and screened for enhanced fluorescence in the NIR. The brightness of optimized PAS-GAF variants increased more than threefold compared to that of wt AphB(1-321), with only insignificant spectral shifts (Amax around 695 nm, and Fmax around 720 nm). In general, the brightness increases with decreasing wavelengths, which allows for a selection of the fluorophore depending on the optical properties of the tissue. A spectral heterogeneity was observed when residue His260, located in close proximity to the chromophore, was mutated to Tyr, emphasizing the strong effects of the environment on the electronic properties of the bound biliverdin chromophore.

  12. Combined nonlinear laser imaging (two-photon excitation fluorescence, second and third-harmonic generation, and fluorescence lifetime imaging microscopies) in ovarian tumors

    Science.gov (United States)

    Adur, J.; Pelegati, V. B.; de Thomaz, A. A.; Bottcher-Luiz, F.; Andrade, L. A. L. A.; Almeida, D. B.; Carvalho, H. F.; Cesar, C. L.

    2012-03-01

    We applied Two-photon Excited Fluorescence (TPEF), Second/Third Harmonic Generation (SHG and THG) and Fluorescence Lifetime Imaging (FLIM) Non Linear Optics (NLO) Laser-Scanning Microscopy within the same imaging platform to evaluate their use as a diagnostic tool in ovarian tumors. We assess of applicability of this multimodal approach to perform a pathological evaluation of serous and mucinous tumors in human samples. The combination of TPEF-SHG-THG imaging provided complementary information about the interface epithelium/stromal, such as the transformation of epithelium surface (THG) and the overall fibrillar tissue architecture (SHG). The fact that H&E staining is the standard method used in clinical pathology and that the stored samples are usually fixed makes it important a re-evaluation of these samples with NLO microscopy to compare new results with a library of already existing samples. FLIM, however, depends on the chemical environment around the fluorophors that was completely changed after fixation; therefore it only makes sense in unstained samples. Our FLIM results in unstained samples demonstrate that it is possible to discriminate healthy epithelia from serous or mucinous epithelia. Qualitative and quantitative analysis of the different imaging modalities used showed that multimodal nonlinear microscopy has the potential to differentiate between cancerous and healthy ovarian tissue.

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

    Indian Academy of Sciences (India)

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

    2014-02-01

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

  14. Arsenic in marine tissues — The challenging problems to electrothermal and hydride generation atomic absorption spectrometry

    Science.gov (United States)

    Karadjova, Irina B.; Petrov, Panayot K.; Serafimovski, Ivan; Stafilov, Trajče; Tsalev, Dimiter L.

    2007-03-01

    Analytical problems in determination of arsenic in marine tissues are addressed. Procedures for the determination of total As in solubilized or extracted tissues with tetramethylammonium hydroxide and methanol have been elaborated. Several typical lyophilized tissues were used: NIST SRM 1566a 'Oyster Tissue', BCR-60 CRM 'Trace Elements in an Aquatic Plant ( Lagarosiphon major)', BCR-627 'Forms of As in Tuna Fish Tissue', IAEA-140/TM 'Sea Plant Homogenate', NRCC DOLT-1 'Dogfish Liver' and two representatives of the Black Sea biota, Mediterranean mussel ( Mytilus galloprovincialis) and Brown algae ( Cystoseira barbata). Tissues (nominal 0.3 g) were extracted in tetramethylammonium hydroxide (TMAH) 1 ml of 25% m/v TMAH and 2 ml of water) or 5 ml of aqueous 80% v/v methanol (MeOH) in closed vessels in a microwave oven at 50 °C for 30 min. Arsenic in solubilized or extracted tissues was determined by electrothermal atomic absorption spectrometry (ETAAS) after appropriate dilution (nominally to 25 ml, with further dilution as required) under optimal instrumental parameters (pyrolysis temperature 900 °C and atomization temperature 2100 °C) with 1.5 μg Pd as modifier on Zr-Ir treated platform. Platforms have been pre-treated with 2.7 μmol of zirconium and then with 0.10 μmol of iridium which served as a permanent chemical modifier in direct ETAAS measurements and as an efficient hydride sequestration medium in flow injection hydride generation (FI-HG)-ETAAS. TMAH and methanol extract 96-108% and 51-100% of As from CRMs. Various calibration approaches have been considered and critically evaluated. The effect of species-dependent slope of calibration graph or standard additions plot for total As determination in a sample comprising of several individual As species with different ETAAS behavior has been considered as a kind of 'intrinsic element speciation interference' that cannot be completely overcome by standard additions technique. Calibration by means of CRMs has

  15. Arsenic in marine tissues - The challenging problems to electrothermal and hydride generation atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Karadjova, Irina B.; Petrov, Panayot K. [Faculty of Chemistry, University of Sofia, 1 James Bourchier Blvd., Sofia 1164 (Bulgaria); Serafimovski, Ivan [Food Institute, Faculty of Veterinary Medicine, Sts. Cyril and Methodius University, P.O. Box 95, MK-1000, Skopje (Macedonia, The Former Yugoslav Republic of); Stafilov, Trajce [Institute of Chemistry, Faculty of Science, Sts. Cyril and Methodius University, P.O. Box 162, MK-1000, Skopje (Macedonia, The Former Yugoslav Republic of); Tsalev, Dimiter L. [Faculty of Chemistry, University of Sofia, 1 James Bourchier Blvd., Sofia 1164 (Bulgaria)], E-mail: tsalev@chem.uni-sofia.bg

    2007-03-15

    Analytical problems in determination of arsenic in marine tissues are addressed. Procedures for the determination of total As in solubilized or extracted tissues with tetramethylammonium hydroxide and methanol have been elaborated. Several typical lyophilized tissues were used: NIST SRM 1566a 'Oyster Tissue', BCR-60 CRM 'Trace Elements in an Aquatic Plant (Lagarosiphon major)', BCR-627 'Forms of As in Tuna Fish Tissue', IAEA-140/TM 'Sea Plant Homogenate', NRCC DOLT-1 'Dogfish Liver' and two representatives of the Black Sea biota, Mediterranean mussel (Mytilus galloprovincialis) and Brown algae (Cystoseira barbata). Tissues (nominal 0.3 g) were extracted in tetramethylammonium hydroxide (TMAH) 1 ml of 25% m/v TMAH and 2 ml of water) or 5 ml of aqueous 80% v/v methanol (MeOH) in closed vessels in a microwave oven at 50 deg. C for 30 min. Arsenic in solubilized or extracted tissues was determined by electrothermal atomic absorption spectrometry (ETAAS) after appropriate dilution (nominally to 25 ml, with further dilution as required) under optimal instrumental parameters (pyrolysis temperature 900 deg. C and atomization temperature 2100 deg. C) with 1.5 {mu}g Pd as modifier on Zr-Ir treated platform. Platforms have been pre-treated with 2.7 {mu}mol of zirconium and then with 0.10 {mu}mol of iridium which served as a permanent chemical modifier in direct ETAAS measurements and as an efficient hydride sequestration medium in flow injection hydride generation (FI-HG)-ETAAS. TMAH and methanol extract 96-108% and 51-100% of As from CRMs. Various calibration approaches have been considered and critically evaluated. The effect of species-dependent slope of calibration graph or standard additions plot for total As determination in a sample comprising of several individual As species with different ETAAS behavior has been considered as a kind of 'intrinsic element speciation interference' that cannot be completely

  16. Generation of single photons with highly tunable wave shape from a cold atomic quantum memory

    CERN Document Server

    Farrera, Pau; Albrecht, Boris; Ho, Melvyn; Chávez, Matías; Teo, Colin; Sangouard, Nicolas; de Riedmatten, Hugues

    2016-01-01

    We report on a single photon source with highly tunable photon shape based on a cold ensemble of Rubidium atoms. We follow the DLCZ scheme to implement an emissive quantum memory, which can be operated as a photon pair source with controllable delay. We find that the temporal wave shape of the emitted read photon can be precisely controlled by changing the shape of the driving read pulse. We generate photons with temporal durations varying over three orders of magnitude up to 10 {\\mu}s without a significant change of the read-out efficiency. We prove the non-classicality of the emitted photons by measuring their antibunching, showing near single photon behavior at low excitation probabilities. We also show that the photons are emitted in a pure state by measuring unconditional autocorrelation functions. Finally, to demonstrate the usability of the source for realistic applications, we create ultra-long single photons with a rising exponential or doubly peaked wave shape which are important for several quantum...

  17. Characterization of the photocurrents generated by the laser of atomic force microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Yanfeng; Hui, Fei; Shi, Yuanyuan; Lanza, Mario, E-mail: mlanza@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Collaborative Innovation Center of Suzhou Nanoscience and Technology, Soochow University, 199 Ren-Ai Road, Suzhou 215123 (China); Iglesias, Vanessa [International Iberian Nanotechnology Laboratory, 4715-330 Braga (Portugal); Lewis, David [Nanonics Imaging, Har Hotzvim, Jerusalem 91487 (Israel); Niu, Jiebin; Long, Shibing; Liu, Ming [Laboratory of Nanofabrication and Novel Device Integration, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029 (China); Hofer, Alexander; Frammelsberger, Werner; Benstetter, Guenther [Deggendorf Institute of Technology, Edlmairstr. 6+8, 94469 Deggendorf (Germany); Scheuermann, Andrew; McIntyre, Paul C. [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

    2016-08-15

    The conductive atomic force microscope (CAFM) has become an essential tool for the nanoscale electronic characterization of many materials and devices. When studying photoactive samples, the laser used by the CAFM to detect the deflection of the cantilever can generate photocurrents that perturb the current signals collected, leading to unreliable characterization. In metal-coated semiconductor samples, this problem is further aggravated, and large currents above the nanometer range can be observed even without the application of any bias. Here we present the first characterization of the photocurrents introduced by the laser of the CAFM, and we quantify the amount of light arriving to the surface of the sample. The mechanisms for current collection when placing the CAFM tip on metal-coated photoactive samples are also analyzed in-depth. Finally, we successfully avoided the laser-induced perturbations using a two pass technique: the first scan collects the topography (laser ON) and the second collects the current (laser OFF). We also demonstrate that CAFMs without a laser (using a tuning fork for detecting the deflection of the tip) do not have this problem.

  18. Characterization of the photocurrents generated by the laser of atomic force microscopes.

    Science.gov (United States)

    Ji, Yanfeng; Hui, Fei; Shi, Yuanyuan; Iglesias, Vanessa; Lewis, David; Niu, Jiebin; Long, Shibing; Liu, Ming; Hofer, Alexander; Frammelsberger, Werner; Benstetter, Guenther; Scheuermann, Andrew; McIntyre, Paul C; Lanza, Mario

    2016-08-01

    The conductive atomic force microscope (CAFM) has become an essential tool for the nanoscale electronic characterization of many materials and devices. When studying photoactive samples, the laser used by the CAFM to detect the deflection of the cantilever can generate photocurrents that perturb the current signals collected, leading to unreliable characterization. In metal-coated semiconductor samples, this problem is further aggravated, and large currents above the nanometer range can be observed even without the application of any bias. Here we present the first characterization of the photocurrents introduced by the laser of the CAFM, and we quantify the amount of light arriving to the surface of the sample. The mechanisms for current collection when placing the CAFM tip on metal-coated photoactive samples are also analyzed in-depth. Finally, we successfully avoided the laser-induced perturbations using a two pass technique: the first scan collects the topography (laser ON) and the second collects the current (laser OFF). We also demonstrate that CAFMs without a laser (using a tuning fork for detecting the deflection of the tip) do not have this problem.

  19. Generating and characterizing the mechanical properties of cell-derived matrices using atomic force microscopy.

    Science.gov (United States)

    Tello, Marta; Spenlé, Caroline; Hemmerlé, Joseph; Mercier, Luc; Fabre, Roxane; Allio, Guillaume; Simon-Assmann, Patricia; Goetz, Jacky G

    2016-02-01

    Mechanical interaction between cells and their surrounding extracellular matrix (ECM) controls key processes such as proliferation, differentiation and motility. For many years, two-dimensional (2D) models were used to better understand the interactions between cells and their surrounding ECM. More recently, variation of the mechanical properties of tissues has been reported to play a major role in physiological and pathological scenarios such as cancer progression. The 3D architecture of the ECM finely tunes cellular behavior to perform physiologically relevant tasks. Technical limitations prevented scientists from obtaining accurate assessment of the mechanical properties of physiologically realistic matrices. There is therefore a need for combining the production of high-quality cell-derived 3D matrices (CDMs) and the characterization of their topographical and mechanical properties. Here, we describe methods that allow to accurately measure the young modulus of matrices produced by various cellular types. In the first part, we will describe and review several protocols for generating CDMs matrices from endothelial, epithelial, fibroblastic, muscle and mesenchymal stem cells. We will discuss tools allowing the characterization of the topographical details as well as of the protein content of such CDMs. In a second part, we will report the methodologies that can be used, based on atomic force microscopy, to accurately evaluate the stiffness properties of the CDMs through the quantification of their young modulus. Altogether, such methodologies allow characterizing the stiffness and topography of matrices deposited by the cells, which is key for the understanding of cellular behavior in physiological conditions.

  20. Next-Generation Lithium Metal Anode Engineering via Atomic Layer Deposition.

    Science.gov (United States)

    Kozen, Alexander C; Lin, Chuan-Fu; Pearse, Alexander J; Schroeder, Marshall A; Han, Xiaogang; Hu, Liangbing; Lee, Sang-Bok; Rubloff, Gary W; Noked, Malachi

    2015-06-23

    Lithium metal is considered to be the most promising anode for next-generation batteries due to its high energy density of 3840 mAh g(-1). However, the extreme reactivity of the Li surface can induce parasitic reactions with solvents, contamination, and shuttled active species in the electrolyte, reducing the performance of batteries employing Li metal anodes. One promising solution to this issue is application of thin chemical protection layers to the Li metal surface. Using a custom-made ultrahigh vacuum integrated deposition and characterization system, we demonstrate atomic layer deposition (ALD) of protection layers directly on Li metal with exquisite thickness control. We demonstrate as a proof-of-concept that a 14 nm thick ALD Al2O3 layer can protect the Li surface from corrosion due to atmosphere, sulfur, and electrolyte exposure. Using Li-S battery cells as a test system, we demonstrate an improved capacity retention using ALD-protected anodes over cells assembled with bare Li metal anodes for up to 100 cycles.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  2. Generation and application of a controllable multi-atom entangled state

    Institute of Scientific and Technical Information of China (English)

    Huang Yan-Xia; Zhan Ming-Sheng

    2004-01-01

    In this paper, we present a scheme to prepare a set of the multi-atom entangled states by the cavity quantum electrodynamics (QED) technology. The multi-atom entangled states have some particular entanglement properties.For example, the remaining reduced density matrices Pij still retain entanglement or disentanglement when any N-2atoms of the N atoms are traced out, which can be chosen freely according to our need, and the relative entanglement strength of any pair of atoms (measured by the concurrence) can be arbitrarily adjusted. In addition, they may be completely symmetric under the exchange of any two atoms, and perform certain quantum information tasks, such as telecloning, teleportation, secret sharing and so on.

  3. Generation and application of a controllable multi-atom entangled state

    Science.gov (United States)

    Huang, Yan-Xia; Zhan, Ming-Sheng

    2004-12-01

    In this paper, we present a scheme to prepare a set of the multi-atom entangled states by the cavity quantum electrodynamics (QED) technology. The multi-atom entangled states have some particular entanglement properties. For example, the remaining reduced density matrices ρij still retain entanglement or disentanglement when any N-2 atoms of the N atoms are traced out, which can be chosen freely according to our need and the relative entanglement strength of any pair of atoms (measured by the concurrence) can be arbitrarily adjusted. In addition, they may be completely symmetric under the exchange of any two atoms and perform certain quantum information tasks, such as telecloning, teleportation, secret sharing and so on.

  4. Chronological analysis with fluorescent timer reveals unique features of newly generated β-cells.

    Science.gov (United States)

    Miyatsuka, Takeshi; Matsuoka, Taka-aki; Sasaki, Shugo; Kubo, Fumiyo; Shimomura, Iichiro; Watada, Hirotaka; German, Michael S; Hara, Manami

    2014-10-01

    Although numerous studies have uncovered the molecular mechanisms regulating pancreas development, it remains to be clarified how β-cells arise from progenitors and how recently specified β-cells are different from preexisting β-cells. To address these questions, we developed a mouse model in which the insulin 1 promoter drives DsRed-E5 Timer fluorescence that shifts its spectrum over time. In transgenic embryos, green fluorescent β-cells were readily detected by FACS and could be distinguished from mature β-cells only until postnatal day 0, suggesting that β-cell neogenesis occurs exclusively during embryogenesis. Transcriptome analysis with green fluorescent cells sorted by FACS demonstrated that newly differentiated β-cells highly expressed progenitor markers, such as Sox9, Neurog3, and Pax4, showing the progenitor-like features of newborn β-cells. Flow cytometric analysis of cell cycle dynamics showed that green fluorescent cells were mostly quiescent, and differentiated β-cells were mitotically active. Thus, the precise temporal resolution of this model enables us to dissect the unique features of newly specified insulin-producing cells, which could enhance our understanding of β-cell neogenesis for future cell therapy. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  5. Recyclable decoration of amine-functionalized magnetic nanoparticles with Ni(2+) for determination of histidine by photochemical vapor generation atomic spectrometry.

    Science.gov (United States)

    Hu, Yuan; Wang, Qi; Zheng, Chengbin; Wu, Li; Hou, Xiandeng; Lv, Yi

    2014-01-07

    It is critically important to accurately determine histidine since it is an indicator for many diseases when at an abnormal level. Here, an inexpensive and simple method using an amine-functionalized magnetic nanoparticle-based Ni(2+)-histidine affinity pair system was developed for highly sensitive and selective detection of histidine in human urine by photochemical vapor generation atomic spectrometry. Ni(2+) was first bound to the amine groups of the amine-functionalized magnetic nanoparticles and then liberated to solution via the highly specific interaction between the histidine and Ni(2+) in the presence of histidine. The liberated histidine-Ni(2+) complex was exposed to UV irradiation in the presence of formic acid to form gaseous nickel tetracarbonyl, which was separated from the sample matrix and determined by atomic absorption/fluorescence spectrometry. Compared to other methods, this approach promises high sensitivity, simplicity in design, and convenient operation. The need for organic solvents, enzymatic reactions, separation processes, chemical modification, expensive instrumentations, and sophisticated and complicated pretreatment is minimized with this strategy. A limit of detection of 1 nM was obtained and provided tens-to-hundreds of fold improvements over that achieved with conventional methods. The protocol was evaluated by analysis of several urine samples with good recoveries and showed great potential for practical application.

  6. Longitudinal diffusion behavior of hemicyanine dyes across phospholipid vesicle membranes as studied by second-harmonic generation and fluorescence spectroscopies.

    Science.gov (United States)

    Yamaguchi, Akira; Nakano, Masaki; Nochi, Kimihisa; Yamashita, Tomohisa; Morita, Kotaro; Teramae, Norio

    2006-10-01

    The adsorption and longitudinal diffusion behaviors of a series of hemicyanine dyes to phospholipid vesicle membranes were studied by second-harmonic generation (SHG) and fluorescence spectroscopies. It was observed that the longitudinal diffusion of cationic hemicyanine dyes takes place immediately after the initial adsorption of these dyes to the outer surface of the vesicle membrane. In contrast, hardly any amount of a zwitterionic hemicyanine dye with a sulfonate group diffused across the vesicle membrane within the measurement time (<2000 s). Based on the difference in the time-course responses of SHG and fluorescence spectroscopies for all of the hemicyanine dyes tested, we propose that hydration of the sulfonate group is mainly responsible for the low diffusivity of the zwitterionic hemicyanine dye.

  7. Two-photon fluorescence and second-harmonic generation imaging of collagen in human tissue based on multiphoton microscopy.

    Science.gov (United States)

    Jiang, Xingshan; Zhong, Jiazhao; Liu, Yuchun; Yu, Haibo; Zhuo, Shuangmu; Chen, Jianxin

    2011-01-01

    Multiphoton microscopic imaging of collagen plays an important role in noninvasive diagnoses of human tissue. In this study, two-photon fluorescence and second-harmonic generation (SHG) imaging of collagen in human skin dermis and submucosa of colon and stomach tissues were investigated based on multiphoton microscopy (MPM). Our results show that multiphoton microscopic image of collagen bundles exhibits apparently different pattern in human tissues. The collagen bundles can simultaneously reveal its SHG and two-photon excited fluorescence images in the submucosa of colon and stomach, whereas it solely emit SHG signal in skin dermis. The intensity spectral information from tissues further demonstrated the above results. This indicates that collagen bundles have completely different space arrangement in these tissues. Our experimental results bring more detailed information of collagen for the application of MPM in human noninvasive imaging. Copyright © 2011 Wiley Periodicals, Inc.

  8. Multiphoton microscopic imaging of adipose tissue based on second-harmonic generation and two-photon excited fluorescence.

    Science.gov (United States)

    Huang, Zufang; Zhuo, Shuangmu; Chen, Jianxin; Chen, Rong; Jiang, Xingshan

    2008-01-01

    The fresh adipose tissue was investigated by the use of multiphoton microscopy (MPM) based on two-photon excited fluorescence and second-harmonic generation (SHG). Microstructure of collagen and adipose cells in the adipose tissue is clearly imaged at a subcellular level with the excitation light wavelengths of 850 and 730 nm, respectively. The emission spectrum of collagen SHG signal and NADH and FAD fluorescence signal can also be obtained, which can be used to quantify the content of collagen and adipose cells and reflect the degree of pathological changes when comparing normal tissue with abnormal adipose tissue in the same condition. The results indicate that MPM has the potential to be applied to investigate the adipose tissue and can be used in the research field of lipid and connective tissues.

  9. Modulation of Exciton Generation in Organic Active Planar pn Heterojunction: Toward Low Driving Voltage and High-Efficiency OLEDs Employing Conventional and Thermally Activated Delayed Fluorescent Emitters.

    Science.gov (United States)

    Chen, Dongcheng; Liu, Kunkun; Gan, Lin; Liu, Ming; Gao, Kuo; Xie, Gaozhan; Ma, Yuguang; Cao, Yong; Su, Shi-Jian

    2016-08-01

    Organic light-emitting diodes (OLEDs) combining low driving voltage and high efficiency are designed by employing conventional and thermally activated delayed fluorescence emitters through modulation of excitons generated at the planar p-n heterojunction region. To date, this approach enables the highest power efficiency for yellow-green emitting fluorescent OLEDs with a simplified structure.

  10. Spin squeezing and Schrödinger cat generation in atomic samples with Rydberg blockade

    DEFF Research Database (Denmark)

    Opatrný, Tomáš; Mølmer, Klaus

    2012-01-01

    A scheme is proposed to prepare squeezed states and Schrödinger-cat-like states of the collective spin degrees of freedom associated with a pair of ground states in an atomic ensemble. The scheme uses an effective Jaynes-Cummings interaction which can be provided by excitation of the atoms...

  11. How much entanglement can be generated between two atoms by detecting photons?

    OpenAIRE

    Lamata, L.; Garcia-Ripoll, J. J.; Cirac, J. I.

    2006-01-01

    It is possible to achieve an arbitrary amount of entanglement between two atoms using only spontaneously emitted photons, linear optics, single photon sources and projective measurements. This is in contrast to all current experimental proposals for entangling two atoms, which are fundamentally restricted to one entanglement bit or ebit.

  12. How much entanglement can be generated between two atoms by detecting photons?

    Science.gov (United States)

    Lamata, L; García-Ripoll, J J; Cirac, J I

    2007-01-05

    It is possible to achieve an arbitrary amount of entanglement between two atoms using only spontaneously emitted photons, linear optics, single-photon sources, and projective measurements. This is in contrast to all current experimental proposals for entangling two atoms, which are fundamentally restricted to one entanglement bit or "ebit."

  13. A rapid and rational approach to generating isomorphous heavy-atom phasing derivatives.

    Science.gov (United States)

    Lu, Jinghua; Sun, Peter D

    2014-09-01

    In attempts to replace the conventional trial-and-error heavy-atom derivative search method with a rational approach, we previously defined heavy metal compound reactivity against peptide ligands. Here, we assembled a composite pH- and buffer-dependent peptide reactivity profile for each heavy metal compound to guide rational heavy-atom derivative search. When knowledge of the best-reacting heavy-atom compound is combined with mass spectrometry assisted derivatization, and with a quick-soak method to optimize phasing, it is likely that the traditional heavy-atom compounds could meet the demand of modern high-throughput X-ray crystallography. As an example, we applied this rational heavy-atom phasing approach to determine a previously unknown mouse serum amyloid A2 crystal structure.

  14. Generation of 99-mW continuous-wave 285-nm radiation for magneto-optical trapping of Mg atoms

    DEFF Research Database (Denmark)

    Madsen, D. N; Yu, P.; Balslev, S.;

    2002-01-01

    We have developed a tunable intense narrow-band 285 nm light source based on frequency doubling of 570 nm light in BBO. At input powers of 840 mW (including 130 mW used for locking purposes) we generate 99 mW UV radiation with an intensity profile suitable for laser-cooling experiments. The light...... is used for laser cooling of neutral magnesium atoms in a magneto-optical trap (MOT). We capture about 5×106 atoms directly from a thermal beam and find that the major loss mechanism of the magnesium MOT is a near-resonant two-photon ionization process....

  15. Generation of 99-mW continuous-wave 285-nm radiation for magneto-optical trapping of Mg atoms

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Yu, Ping; Balslev, Søren;

    2002-01-01

    We have developed a tunable intense narrow-band 285 nm light source based on frequency doubling of 570 nm light in BBO. At input powers of 840 mW (including 130 mW used for locking purposes) we generate 99 mW UV radiation with an intensity profile suitable for laser-cooling experiments. The light...... is used for laser cooling of neutral magnesium atoms in a magneto-optical trap (MOT). We capture about 5 x 10(6) atoms directly from a thermal beam and find that the major loss mechanism of the magnesium MOT is a near-resonant two-photon ionization process....

  16. Generation of 99-mW continuous-wave 285-nm radiation for magneto-optical trapping of Mg atoms

    DEFF Research Database (Denmark)

    Madsen, D. N; Yu, P.; Balslev, S.

    2002-01-01

    We have developed a tunable intense narrow-band 285 nm light source based on frequency doubling of 570 nm light in BBO. At input powers of 840 mW (including 130 mW used for locking purposes) we generate 99 mW UV radiation with an intensity profile suitable for laser-cooling experiments. The light...... is used for laser cooling of neutral magnesium atoms in a magneto-optical trap (MOT). We capture about 5×106 atoms directly from a thermal beam and find that the major loss mechanism of the magnesium MOT is a near-resonant two-photon ionization process....

  17. Generation of 99-mW continuous-wave 285-nm radiation for magneto-optical trapping of Mg atoms

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Yu, Ping; Balslev, Søren

    2002-01-01

    We have developed a tunable intense narrow-band 285 nm light source based on frequency doubling of 570 nm light in BBO. At input powers of 840 mW (including 130 mW used for locking purposes) we generate 99 mW UV radiation with an intensity profile suitable for laser-cooling experiments. The light...... is used for laser cooling of neutral magnesium atoms in a magneto-optical trap (MOT). We capture about 5 x 10(6) atoms directly from a thermal beam and find that the major loss mechanism of the magnesium MOT is a near-resonant two-photon ionization process....

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2006-10-02

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-10-02

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

  1. Molecular iodine fluorescence spectra generated with helium-neon lasers for spectrometer calibration.

    Science.gov (United States)

    Williamson, J Charles

    2010-12-01

    Gas-phase molecular iodine laser-induced fluorescence (LIF) spectra were recorded out to 815 nm at 1 cm(-1) resolution using green, yellow, and red helium-neon (HeNe) lasers as excitation sources. Nine previously unreported I(2) B←X absorption transitions accessed by these lasers were identified, and specific rovibronic transition assignments were made for two hundred LIF peaks--more than sixty per laser. These I(2) LIF peaks can be used to calibrate the vacuum wavenumber coordinate of spectrometers to better than 0.1 cm(-1) accuracy. In particular, green HeNe excitation of the I(2) R(106) 28-0 transition leads to strong fluorescence well suited for calibration, with a rotational doublet spacing of 15 cm(-1) and a doublet-to-doublet spacing of 190 cm(-1). Calibration by HeNe I(2) LIF may be an especially valuable technique for Raman spectroscopy applications.

  2. Determination of Inorganic Arsenic Species by Electrochemical Hydride Generation Atomic Absorption Spectrometry with Selective Electrochemical Reduction

    Institute of Scientific and Technical Information of China (English)

    LI Xun; WANG Zheng-Hao

    2007-01-01

    A new direct procedure for the determination of inorganic arsenic species was developed by electrochemical hydride generation atomic absorption spectrometry (EcHG-AAS) with selective electrochemical reduction. The determination of inorganic arsenic species is based on the fact that As(Ⅲ) shows significantly higher absorbance at low electrolytic currents than As(Ⅴ) in 0.3 mol·L-1 H2SO4.The electrolytic current used for the determination of As(Ⅲ) without considerable interferences of As(V) was 0.4 A, whereas the current for the determination of As(Ⅲ)and As(V) was 1.2 A. For equal concentrations of As(Ⅲ) and As(V) in a sample, the interferences of As(V) during the As(Ⅲ) determination were smaller than 5%. The absorbance for As(V) could be calculated by subtracting that for As(Ⅲ) measured at 0.4 A from the total absorbance for As(Ⅲ) and As(V) measured at 1.2 A, and then the concentration of As(V) can be obtained by its calibration curve at 1.2 A. The methodology developed provided the detection limits of 0.3 and 0.6 ng·ml-1 for As(Ⅲ) and As(V) respectively.The relative standrad deviations were of 3.5% for 20 ng·ml-1 As(Ⅲ) and 302% for 20 ng·ml-1 As(V).The method was successfully applied to determination of soluble inorganic arsenic species in Chinese medicine.

  3. Generating Entanglement between Atomic Spins with Low-Noise Probing of an Optical Cavity

    CERN Document Server

    Cox, Kevin C; Greve, Graham P; Thompson, James K

    2015-01-01

    Atomic projection noise limits the ultimate precision of all atomic sensors, including clocks, inertial sensors, magnetometers, etc. The independent quantum collapse of $N$ atoms into a definite state (for example spin up or down) leads to an uncertainty $\\Delta \\theta_{SQL}=1/\\sqrt{N}$ in the estimate of the quantum phase accumulated during a Ramsey sequence or its many generalizations. This phase uncertainty is referred to as the standard quantum limit. Creating quantum entanglement between the $N$ atoms can allow the atoms to partially cancel each other's quantum noise, leading to reduced noise in the phase estimate below the standard quantum limit. Recent experiments have demonstrated up to $10$~dB of phase noise reduction relative to the SQL by making collective spin measurements. This is achieved by trapping laser-cooled Rb atoms in an optical cavity and precisely measuring the shift of the cavity resonance frequency by an amount that depends on the number of atoms in spin up. Detecting the probe light ...

  4. Optimal entropy squeezing sudden generation and its control for an effective two-level moving atom entanglement with the two-mode coherent fields

    Institute of Scientific and Technical Information of China (English)

    Liu Xiao-Juan; Zhou Yuan-Jun; Fang Mao-Fa

    2009-01-01

    From the viewpoint of quantum information, this paper proposes a concept and a definition of the atomic optimal entropy squeezing sudden generation (AOESSG) for the system of an effective two-level moving atom which entangles with the two-mode coherent fields. It also researches the relationship between the AOESSG and entanglement sudden death of the atom-fields, and discusses the influences of atomic initial state on the AOESSG and obtains the system parameter which controls the AOESSG.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-01-21

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

  6. A geração química de vapor em espectrometria atômica Chemical vapor generation in atomic spectrometry

    Directory of Open Access Journals (Sweden)

    Iracema Takase

    2002-12-01

    Full Text Available The historical development of atomic spectrometry techniques based on chemical vapor generation by both batch and flow injection sampling formats is presented. Detection via atomic absorption spectrometry (AAS, microwave induced plasma optical emission spectrometry (MIP-OES, inductively coupled plasma optical emission spectrometry (ICP-OES , inductively coupled plasma mass spectrometry (ICP-MS and furnace atomic nonthermal excitation spectrometry (FANES are considered. Hydride generation is separately considered in contrast to other methods of generation of volatile derivatives. Hg ¾ CVAAS (cold vapor atomic absorption spectrometry is not considered here. The current state-of-the-art, including extension, advantages and limitations of this approach is discussed.

  7. Investigation on the spectral properties of 2D asynchronous fluorescence spectra generated by using variable excitation wavelengths as a perturbation

    Science.gov (United States)

    Wang, Jingdan; He, Anqi; Guo, Ran; Wei, Yongju; Feng, Juan; Xu, Yizhuang; Noda, Isao; Wu, Jinguang

    2016-11-01

    Properties of 2D asynchronous spectra generated from a series of fluorescence emission spectra are investigated. Variable excitation wavelengths are utilized as an external perturbation. Based on the results of mathematical analysis and computer simulation, we find that no cross peak will be produced on the 2D asynchronous spectrum if the fluorescent solute under investigation occurs in a single micro-environment. The observation of cross peaks implies that the fluorescent molecule may occur in different micro-environments in a solution. Based on these results, we use 2D asynchronous spectra to investigate the emission spectra of anthracene dissolved in cyclohexane. When the concentration of anthracene is low, no cross peak is produced in the resultant 2D asynchronous spectrum, confirming that anthracene is dissolved as single molecule in the solution. As the concentration elevated, cross peaks appear in the corresponding 2D asynchronous spectra. A plausible explanation of this phenomenon is that anthracene may undergo aggregation via π-π interaction or π-C-H interaction.

  8. Automatic generation of reaction energy databases from highly accurate atomization energy benchmark sets.

    Science.gov (United States)

    Margraf, Johannes T; Ranasinghe, Duminda S; Bartlett, Rodney J

    2017-03-31

    In this contribution, we discuss how reaction energy benchmark sets can automatically be created from arbitrary atomization energy databases. As an example, over 11 000 reaction energies derived from the W4-11 database, as well as some relevant subsets are reported. Importantly, there is only very modest computational overhead involved in computing >11 000 reaction energies compared to 140 atomization energies, since the rate-determining step for either benchmark is performing the same 140 quantum chemical calculations. The performance of commonly used electronic structure methods for the new database is analyzed. This allows investigating the relationship between the performances for atomization and reaction energy benchmarks based on an identical set of molecules. The atomization energy is found to be a weak predictor for the overall usefulness of a method. The performance of density functional approximations in light of the number of empirically optimized parameters used in their design is also discussed.

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

    Science.gov (United States)

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

    1989-01-01

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

  10. Optical lattice clock with strontium atoms: a second generation of cold atom clocks; Horloge a reseau optique au strontium: une 2. generation d'horloges a atomes froids

    Energy Technology Data Exchange (ETDEWEB)

    Le Targat, R

    2007-07-15

    Atomic fountains, based on a microwave transition of Cesium or Rubidium, constitute the state of the art atomic clocks, with a relative accuracy close to 10{sup -16}. It nevertheless appears today that it will be difficult to go significantly beyond this level with this kind of device. The use of an optical transition, the other parameters being unchanged, gives hope for a 4 or 5 orders of magnitude improvement of the stability and of the relative uncertainty on most systematic effects. As for motional effects on the atoms, they can be controlled on a very different manner if they are trapped in an optical lattice instead of experiencing a free ballistic flight stage, characteristic of fountains. The key point of this approach lies in the fact that the trap can be operated in such a way that a well chosen, weakly allowed, J=0 {yields} J=0 clock transition can be free from light shift effects. In this respect, the strontium atom is one of the most promising candidate, the 1S{sub 0} {yields} 3P{sub 0} transition has a natural width of 1 mHz, and several other easily accessible transitions can be used to efficiently laser cool atoms down to 10 {mu}K. This thesis demonstrates the experimental feasibility of an optical lattice clock based on the strontium atom, and reports on a preliminary evaluation of the relative accuracy with the fermionic isotope {sup 87}Sr, at a level of a few 10{sup -15}. (author)

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

    Science.gov (United States)

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

    2014-11-01

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

  12. Multimodal second harmonic generation and two photon fluorescence imaging of microdomain calcium contraction coupling in single cardiomyocytes

    Science.gov (United States)

    Chan, James; Awasthi, Samir; Izu, Leighton; Mao, Ziliang; Jian, Zhong; Landas, Trevor; Lerner, Aaron; Shimkunas, Rafael; Woldeyesus, Rahwa; Bossuyt, Julie; Wood, Brittani; Chen, Yi-Je; Matthews, Dennis; Lieu, Deborah; Chiamvimonvat, Nipavan; Lam, Kit; Chen-Izu, Ye

    2016-11-01

    The objective of this study was to develop a method for simultaneously measuring the calcium and contraction dynamics of single, live cardiomyocytes at high spatial resolutions. Such measurements are important to investigate local calcium release and the mechanical response at the sarcomere level (i.e. the basic unit of contraction), which have important implications in cardiac dysfunction and arrhythmias in conditions such as hypertension, atrial fibrillation, and myocardial infarction. Here, we describe a multimodal second harmonic generation (SHG) and two photon fluorescence (2PF) microscopy technique that is used to simultaneously measure subsarcomere calcium and contraction events at high spatial and temporal resolutions. The method takes advantage of the label-free nature of SHG for imaging the sarcomeres and the high spatial colocalization of the SHG signal and the fluorescence signal excited from calcium indicators. This microscope was used to measure calcium sparks and waves and associated contractions in subcellular microdomains, leading to the generation of subcellular strain. We anticipate this new imaging tool will play an important role in studying mechanical stress-induced heart disease.

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

    Science.gov (United States)

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

    2008-09-10

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

  14. Prospects of charged-oscillator quantum-state generation with Rydberg atoms

    Science.gov (United States)

    Stevenson, Robin; Minář, Jiří; Hofferberth, Sebastian; Lesanovsky, Igor

    2016-10-01

    We explore the possibility of engineering quantum states of a charged mechanical oscillator by coupling it to a stream of atoms in superpositions of high-lying Rydberg states. Our scheme relies on the driving of a two-phonon resonance within the oscillator by coupling it to an atomic two-photon transition. This approach effectuates a controllable open system dynamics on the oscillator that in principle permits versatile dissipative creation of squeezed and other nonclassical states which are central to sensing applications or for studies of fundamental questions concerning the boundary between classical and quantum-mechanical descriptions of macroscopic objects. We show that these features survive thermal coupling of the oscillator with the environment. We perform a detailed feasibility study finding that current state-of-the-art parameters result in atom-oscillator couplings which are too weak to efficiently implement the proposed oscillator state preparation protocol. Finally, we comment on ways to circumvent the present limitations.

  15. A New Generation of Atomic Clocks: Accuracy and Stability at the 10^{-18} Level

    CERN Document Server

    Bloom, B J; Williams, J R; Campbell, S L; Bishof, M; Zhang, X; Zhang, W; Bromley, S L; Ye, J

    2013-01-01

    The exquisite control exhibited over quantum states of individual particles has revolutionized the field of precision measurement, as exemplified by the most accurate atomic clock realized in single trapped ions. Whereas many-atom lattice clocks have shown advantages in measurement precision over trapped-ion clocks, their accuracy has remained 20 times worse. Here we demonstrate, for the first time, that a many-atom system achieves accuracy (6x10^{-18}) better than a single ion-based clock, with vastly reduced averaging times (3000 s). This is the first time a single clock has achieved the best performance in all three key ingredients necessary for consideration as a primary standard - stability, reproducibility, and accuracy. This work paves the way for future experiments to integrate many-body quantum state engineering into the frontiers of quantum metrology, creating exciting opportunities to advance precision beyond the standard quantum limit. Improved frequency standards will have impact to a wide range ...

  16. Absorption-Amplification Response with or Without Spontaneously Generated Coherence in a Coherent Four-Level Atomic Medium

    Institute of Scientific and Technical Information of China (English)

    LI Jia-Hua; YANG Wen-Xing; PENG Ju-Cun

    2004-01-01

    We discuss and analyze the absorption-amplification properties of a weak probe field in a typical four-level atomic system in the presence of an additional coherence term, the spontaneously generated coherence term. Theinfluences of the spontaneously generated coherence and a coherent pump field on the probe absorption (amplification)are investigated in detail. We show that the absorption of such a weak probe field can be dramatically enhanced dueto the presence of the spontaneously generated coherence. At the same time, the probe-absorption profile exhibitsthe double-peak structure and the probe-absorption peak gradually decreases as the pump intensity increases. On thecontrary, the amplification of such a weak probe field near the line center of the probe transition can be achieved byadjusting the coherent pump field intensity in the absence of the spontaneously generated coherence.

  17. Absorption-Amplification Response with or Without Spontaneously Generated Coherence in a Coherent Four-Level Atomic Medium

    Institute of Scientific and Technical Information of China (English)

    LIJia-Hua; YANGWen-Xing; PENGJu-Cun

    2004-01-01

    We discuss and analyze the absorption-amplification properties of a weak probe field in a typical fourlevel atomic system in the presence of an additional coherence term, the spontaneously generated coherence term. The influences of the spontaneously generated coherence and a coherent pump field on the probe absorption (amplification) are investigated in detail. We show that the absorption of such a weak probe field can be dramatically enhanced due to the presence of the spontaneously generated coherence. At the same time, the probe-absorption profile exhibits the double-peak structure and the probe-absorption peak gradually decreases as the pump intensity increases. On the contrary, the amplification of such a weak probe field near the line center of the probe transition can be achieved by adiusting the coherent Dump field intensity in the absence of the spontaneously generated coherence.

  18. 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

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

    Science.gov (United States)

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

    2017-04-01

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

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

    Institute of Scientific and Technical Information of China (English)

    童诚; 吴银银; 马文

    2015-01-01

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

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

    Science.gov (United States)

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

    2012-12-01

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

  2. Femtosecond electron diffraction. Next generation electron sources for atomically resolved dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Hirscht, Julian

    2015-08-15

    Three instruments for femtosecond electron diffraction (FED) experiments were erected, partially commissioned and used for first diffraction experiments. The Relativistic Electron Gun for Atomic Exploration (REGAE) was completed by beamline elements including supports, a specimen chamber and dark current or electron beam collimating elements such that the commissioning process, including first diffraction experiments in this context, could be started. The temporal resolution of this machine is simulated to be 25 fs (fwhm) short, while a transverse coherence length of 30 nm (fwhm) is feasible to resolve proteins on this scale. Whether this machine is capable of meeting these predictions or whether the dynamics of the electron beam will stay limited by accelerator components, is not finally determined by the end of this work, because commissioning and improvement of accelerator components is ongoing. Simultaneously, a compact DC electron diffraction apparatus, the E-Gun 300, designed for solid and liquid specimens and a target electron energy of 300 keV, was built. Fundamental design issues of the high potential carrying and beam generating components occurred and are limiting the maximum potential and electron energy to 120 keV. Furthermore, this is limiting the range of possible applications and consequently the design and construction of a brand new instrument began. The Femtosecond Electron Diffraction CAmera for Molecular Movies (FED-CAMM) bridges the performance problems of very high electric potentials and provides optimal operational conditions for all applied electron energies up to 300 keV. The variability of gap spacings and optimized manufacturing of the high voltage electrodes lead to the best possible electron pulse durations obtainable with a compact DC setup, that does not comprise of rf-structures. This third apparatus possesses pulse durations just a few tenth femtoseconds apart from the design limit of the highly relativistic REGAE and combines the

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-11-15

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

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

    Science.gov (United States)

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

    2014-03-16

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

  5. Development of a reverse genetics system to generate a recombinant Ebola virus Makona expressing a green fluorescent protein

    Energy Technology Data Exchange (ETDEWEB)

    Albariño, César G., E-mail: calbarino@cdc.gov; Wiggleton Guerrero, Lisa; Lo, Michael K.; Nichol, Stuart T.; Towner, Jonathan S.

    2015-10-15

    Previous studies have demonstrated the potential application of reverse genetics technology in studying a broad range of aspects of viral biology, including gene regulation, protein function, cell entry, and pathogenesis. Here, we describe a highly efficient reverse genetics system used to generate recombinant Ebola virus (EBOV) based on a recent isolate from a human patient infected during the 2014–2015 outbreak in Western Africa. We also rescued a recombinant EBOV expressing a fluorescent reporter protein from a cleaved VP40 protein fusion. Using this virus and an inexpensive method to quantitate the expression of the foreign gene, we demonstrate its potential usefulness as a tool for screening antiviral compounds and measuring neutralizing antibodies. - Highlights: • Recombinant Ebola virus (EBOV) derived from Makona variant was rescued. • New protocol for viral rescue allows 100% efficiency. • Modified EBOV expresses a green fluorescent protein from a VP40-fused protein. • Modified EBOV was tested as tool to screen antiviral compounds and measure neutralizing antibodies.

  6. The influence of spill-line geometry on a spray generated by a pressure-swirl atomizer

    Directory of Open Access Journals (Sweden)

    Malý Milan

    2016-01-01

    Full Text Available An experimental investigation of characteristics of spray generated by a pressure-swirl atomizer (spill-return type was performed using shadowgraphy and Phase-Doppler Anemometry (PDA. Several different geometries of the spill-return orifice were tested in terms of a spray stability and quality on a cold test bench. PDA measurement yields a drop-size distribution and velocity data while the shadowgraphy unveils a break-up process in detail. Performed measurements reveal significant differences in spray characteristics as well as differences in spray stability. The results suggest that the air core, formed inside the swirl chamber, passes through the spill orifice, which causes instability of the inner flow. These instabilities lead to a chaotic state of sheet breakup resulting in shortening of breakup distance. Obtained findings are used to propose possible changes in the atomizer design for improvement of its performance.

  7. Second-harmonic generation in quaternary atomically thin layered AgInP2S6 crystals

    Science.gov (United States)

    Wang, Xingzhi; Du, Kezhao; Liu, Weiwei; Hu, Peng; Lu, Xin; Xu, Weigao; Kloc, Christian; Xiong, Qihua

    2016-09-01

    Nonlinear effects in two-dimensional (2D) atomic layered materials have attracted increasing interest. Here, we report the observation of optical second-harmonic generation (SHG) in two-dimensional atomically thin silver indium phosphorus sulfide (AgInP2S6) crystals, with odd layer thickness. The nonlinear signal facilitates the use of thickness-dependent SHG intensity to investigate the stacking type of this material, while the crystal-orientation dependent SHG intensity of the monolayer sample reveals the rotational symmetry of the AgInP2S6 lattice in plane. Our studies expand the 2D crystal family in nonlinear effect field, which opened considerable promise to the functionalities and potential applications of 2D materials.

  8. Generation of GHZ entangled states of photons in multiple cavities via a superconucting qubit or an atom through resonant interaction

    CERN Document Server

    Yang, Chui-Ping

    2012-01-01

    We propose a method to generate a GHZ entangled state of n photons in n microwave cavities (or resonators) via resonant interaction to a single superconducting qubit. By performing local operations on a qubit (e.g., a solid-state qubit, an atom, etc.) placed in each cavity, the created GHZ states of n photons can be transferred to qubits for storage. The proposed scheme greatly reduces effect of decoherence since only resonant qubit-cavity interaction and resonant qubit-pulse interaction are involved, and no measurement is required. In addition, we show that the method can be applied to create a GHZ state of photons in multiple cavities via an atom through resonant interaction with no measurement needed.

  9. Femtosecond Electron Diffraction: Next generation electron sources for atomically resolved dynamics

    OpenAIRE

    Hirscht, Julian

    2015-01-01

    Three instruments for femtosecond electron diffraction (FED) experiments were erected, partially commissioned and used for first diffraction experiments. The Relativistic Electron Gun for Atomic Exploration (REGAE) was completed by beamline elements including supports, a specimen chamber and dark current or electron beam collimating elements such that the commissioning process, including first diffraction experiments in this context, could be started. The temporal resolution of this machine i...

  10. MULTIPHOTON MICROSCOPIC IMAGING OF MOUSE INTESTINAL MUCOSA BASED ON TWO-PHOTON EXCITED FLUORESCENCE AND SECOND HARMONIC GENERATION

    Directory of Open Access Journals (Sweden)

    REN'AN XU

    2013-01-01

    Full Text Available Multiphoton microscopy (MPM, based on two-photon excited fluorescence and second harmonic generation, enables direct noninvasive visualization of tissue architecture and cell morphology in live tissues without the administration of exogenous contrast agents. In this paper, we used MPM to image the microstructures of the mucosa in fresh, unfixed, and unstained intestinal tissue of mouse. The morphology and distribution of the main components in mucosa layer such as columnar cells, goblet cells, intestinal glands, and a little collagen fibers were clearly observed in MPM images, and then compared with standard H&E images from paired specimens. Our results indicate that MPM combined with endoscopy and miniaturization probes has the potential application in the clinical diagnosis and in vivo monitoring of early intestinal cancer.

  11. Microscopic imaging of glyceraldehyde-induced tissue glycation with intrinsic second harmonic generation and two-photon fluorescence contrasts

    Science.gov (United States)

    Hwang, Yu Jer; Granelli, Joseph; Tirumalasetty, Manasa; Lyubovitsky, Julia

    2013-02-01

    The bioinspired approaches to tissue strengthening and preservation rely on non-toxic cross-linking agents one of which is glyceraldehyde. In this study we used multiphoton microscopy that employs second harmonic generation (SHG) contrast to evaluate collagen microstructures and two-photon fluorescence (TPF) contrast to monitor progression of cross-linking upon treatment of tissues with glyceraldehyde. We examined collagen hydrogels assembled at 37 °C and 27 °C, bovine scleral and corneal tissues, skin as well as rat tail tendons. The results show a different effect of glyceraldehyde on collagen microstructures within the above tissues. This effect depends on the original microstructural assembly of collagen within a specific tissue. Our data suggests that epidermis (in skin and cornea) will protect collagen from cross-linking with glyceraldehyde. The work highlights benefits of monitoring progression of collagen cross-linking and effects of cross-linking on fiber microstructures as imaged with SHG and TPF signals.

  12. Transformation of the rodent malaria parasite Plasmodium chabaudi and generation of a stable fluorescent line PcGFPCON

    Directory of Open Access Journals (Sweden)

    Reece Sarah E

    2008-09-01

    Full Text Available Abstract Background The rodent malaria parasite Plasmodium chabaudi has proven of great value in the analysis of fundamental aspects of host-parasite-vector interactions implicated in disease pathology and parasite evolutionary ecology. However, the lack of gene modification technologies for this model has precluded more direct functional studies. Methods The development of in vitro culture methods to yield P. chabaudi schizonts for transfection and conditions for genetic modification of this rodent malaria model are reported. Results Independent P. chabaudi gene-integrant lines that constitutively express high levels of green fluorescent protein throughout their life cycle have been generated. Conclusion Genetic modification of P. chabaudi is now possible. The production of genetically distinct reference lines offers substantial advances to our understanding of malaria parasite biology, especially interactions with the immune system during chronic infection.

  13. Next Generation of Advanced Laser Fluorescence Technology for Characterization of Natural Aquatic Environments

    Science.gov (United States)

    2011-09-01

    described in a manuscript to be sumbitted in Oct. 2011 for peer review publication in the Journal of Plankton Reseach (Chekalyuk et al. 2011). 3...pollution, fisheries, coastal management, etc., which may ultimately help to inprove the quality of life. Science Education and Communication The...potential future impact of developing the next generation on the ALF technology will include introduction of the the new scientific data and

  14. Label-free fluorescence lifetime and second harmonic generation imaging microscopy improves quantification of experimental renal fibrosis.

    Science.gov (United States)

    Ranjit, Suman; Dobrinskikh, Evgenia; Montford, John; Dvornikov, Alexander; Lehman, Allison; Orlicky, David J; Nemenoff, Raphael; Gratton, Enrico; Levi, Moshe; Furgeson, Seth

    2016-11-01

    All forms of progressive renal diseases develop a final pathway of tubulointerstitial fibrosis and glomerulosclerosis. Renal fibrosis is usually quantified using histological staining, a process that is time-consuming and pathologist dependent. Here we develop a fast and operator-independent method to measure fibrosis utilizing the murine unilateral ureteral obstruction model which manifests a time-dependent fibrotic increase in obstructed kidneys while the contralateral kidneys are used as controls. After ureteral obstruction, kidneys were analyzed at 7, 14, and 21 days. Fibrosis was quantified using fluorescence lifetime imaging (FLIM) and second harmonic generation (SHG) in a Deep Imaging via Enhanced photon Recovery deep tissue imaging microscope. This microscope was developed for deep tissue along with second and third harmonic generation imaging and has extraordinary sensitivity toward harmonic generation. SHG data suggest the presence of more fibrillar collagen in the obstructed kidneys. The combination of short-wavelength FLIM and SHG analysis results in a robust assessment procedure independent of observer interpretation and let us create criteria to quantify the extent of fibrosis directly from the image. Thus, the FLIM-SHG technique shows remarkable improvement in quantification of renal fibrosis compared to standard histological techniques. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  15. Detecting Neutral Atoms on an Atom Chip

    OpenAIRE

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

    2006-01-01

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

  16. Generation of recombinant Orf virus using an enhanced green fluorescent protein reporter gene as a selectable marker

    Directory of Open Access Journals (Sweden)

    Ning Zhangyong

    2011-12-01

    Full Text Available Abstract Background Reporter genes are often used as a selectable marker for generation of recombinant viruses in order to investigate the mechanism of pathogenesis and to obtain candidate vaccine viruses. Routine selection of the recombinant parapoxvirus is time-consuming and labor intensive. Therefore, developing a novel method for selection is critical. Results In this study, we developed a rapid method to generate recombinant Orf viruses (ORFV based on the enhanced green fluorescent protein (EGFP reporter gene as a selectable marker. The coding sequence of EGFP gene was amplified from pEGFP-N1 vector and subcloned into the pZIPPY-neo/gus plasmid under the control of the early-late vaccinia virus (VACV VV7.5 promoter and flanked by two multiple cloning sites (MCS to generate a novel transfer vector pSPV-EGFP. Using the pSPV-EGFP, two recombination cassettes pSPV-113LF-EGFP-113RF and pSPV-116LF-EGFP-116RF were constructed by cloning the flanking regions of the ORFV113 and ORFV116 and inserted into two MCS flanking the EGFP gene. Using this novel system, two single gene deletion mutants OV-IA82Δ113 and OV-IA82Δ116 were successfully generated. Conclusions This approach shortens the time needed to generate recombinant ORFVs (rORFVs. Thus, the pSPV-EGFP vector provides a direct, fast, and convenient way to manipulate the recombinant viruses, indicating that it is highly suited for its designed purpose.

  17. Compact FPGA-based pulse-sequencer and radio-frequency generator for experiments with trapped atoms

    CERN Document Server

    Pruttivarasin, Thaned

    2015-01-01

    We present a compact FPGA-based pulse sequencer and radio-frequency (RF) generator suitable for experiments with cold trapped ions and atoms. The unit is capable of outputting a pulse sequence with at least 32 TTL channels with a timing resolution of 40 ns and contains a built-in 100 MHz frequency counter for counting electrical pulses from a photo-multiplier tube (PMT). There are 16 independent direct-digital-synthesizers (DDS) RF sources with fast (rise-time of ~60 ns) amplitude switching and sub-mHz frequency tuning from 0 to 800 MHz.

  18. Generation of non-classical correlated photon pairs via a ladder-type atomic configuration: theory and experiment.

    Science.gov (United States)

    Ding, Dong-Sheng; Zhou, Zhi-Yuan; Shi, Bao-Sen; Zou, Xu-Bo; Guo, Guang-Can

    2012-05-07

    We experimentally generate a non-classical correlated two-color photon pair at 780 and 1529.4 nm in a ladder-type configuration using a hot 85Rb atomic vapor with the production rate of ~10(7)/s. The non-classical correlation between these two photons is demonstrated by strong violation of Cauchy-Schwarz inequality by the factor R = 48 ± 12. Besides, we experimentally investigate the relations between the correlation and some important experimental parameters such as the single-photon detuning, the powers of pumps. We also make a theoretical analysis in detail and the theoretical predictions are in reasonable agreement with our experimental results.

  19. Arsenic speciation by hydride generation-quartz furnace atomic absorption spectrometry. Optimization of analytical parameters and application to environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Molenat, N.; Astruc, A.; Holeman, M.; Pinel, R. [Laboratoire de Chimie Analytique Bioinorganique et Environnement, Dept. de Chimie, Faculte des Sciences et Techniques, 64 - Pau (France); Maury, G. [Montpellier-2 Univ., 34 (France). Dept. de Chimie Organique Fine

    1999-11-01

    Analytical parameters of hydride generation, trapping, gas chromatography and atomic absorption spectrometry detection in a quartz cell furnace (HG/GC/QFAAS) device have been optimized in order to develop an efficient and sensitive method for arsenic compounds speciation. Good performances were obtained with absolute detection limits in the range of 0.1 - 0.5 ng for arsenite, arsenate, mono-methyl-arsonic acid (MMAA), dimethyl-arsinic acid (DMAA) and trimethyl-arsine oxide (TMAO). A pH selective reduction for inorganic arsenic speciation was successfully reported. Application to the accurate determination of arsenic compounds in different environmental samples was performed. (authors)

  20. Time-dependent complete-active-space self-consistent-field method for atoms: Application to high-harmonic generation

    CERN Document Server

    Sato, Takeshi; Brezinova, Iva; Lackner, Fabian; Nagele, Stefan; Burgdorfer, Joachim

    2016-01-01

    We present the numerical implementation of the time-dependent complete-active-space self-consistent-field (TD-CASSCF) method [Phys. Rev. A, 88, 023402 (2013)] for atoms driven by a strong linearly polarized laser pulse. The present implementation treats the problem in its full dimensionality and introduces a gauge-invariant frozen-core approximation, an efficient evaluation of the Coulomb mean field scaling linearly with the number of basis functions, and a split-operator method specifically designed for stable propagation of stiff spatial derivative operators. We apply this method to high-harmonic generation in helium, beryllium, and neon and explore the role of electron correlations.

  1. Infrared and thermoelectric power generation in thin atomic layer deposited Nb-doped TiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Harkirat S.; Lang, Brian N.; Schwab, Yosyp; Scarel, Giovanna, E-mail: scarelgx@jmu.edu [Department of Physics and Astronomy, James Madison University, 901 Carrier Drive, Harrisonburg, Virginia 22807 (United States); Niemelä, Janne-Petteri; Karppinen, Maarit [Department of Chemistry, Aalto University, P.O. Box 16100, Aalto, 00076 Finland (Finland)

    2015-01-15

    Infrared radiation is used to radiatively transfer heat to a nanometric power generator (NPG) device with a thermoelectric Nb-doped TiO{sub 2} film deposited by atomic layer deposition (ALD) as the active element, onto a borosilicate glass substrate. The linear rise of the produced voltage with respect to the temperature difference between the “hot” and “cold” junctions, typical of the Seebeck effect, is missing. The discovery of the violation of the Seebeck effect in NPG devices combined with the ability of ALD to tune thermoelectric thin film properties could be exploited to increase the efficiency of these devices for energy harvesting purposes.

  2. A NEW GENERATION OF INSTRUMENTATION AND CAPABILITIES FOR ATOMIC MASS SPECTROMETRY

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    @@ Atomic mass spectrometry,embodied usually as inductively coupled plasma mass spectrometry (ICPMS) or glow-discharge mass spectrometry (GDMS),has become a widely accepted tool for trace and ultra-trace elemental analysis.ICPMS offers detection limits below 1 ppt in solution,a dynamic concentration levels,isotope-analysis and isotope-dilution capabilities,modest matrix interferences,understandable spectral interferences (isobaric overlaps),precision in range of 2—5%,and rapid measurements (typically 10 seconds per isotope).

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

    CERN Document Server

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

    2015-01-01

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

  4. Broadband atomic-layer MoSsub>2sub> optical modulators for ultrafast pulse generations in the visible range.

    Science.gov (United States)

    Zhang, Yuxia; Yu, Haohai; Zhang, Rui; Zhao, Gang; Zhang, Huaijin; Chen, Yanxue; Mei, Liangmo; Tonelli, Mauro; Wang, Jiyang

    2017-02-01

    Visible lasers are a fascinating regime, and their significance is illustrated by the 2014 Noble prizes in physics and chemistry. With the development of blue laser diodes (LDs), the LD-pumped solid-state visible lasers become a burgeoning direction today. Constrained by the scarce visible optical modulators, the solid-state ultrafast visible lasers are rarely realized. Based on the bandgap structure and optoelectronic properties of atomic-layer MoSsub>2sub>, it can be proposed that MoSsub>2sub> has the potential as a visible optical modulator. Here, by originally revealing layer-dependent nonlinear absorption of the atomic-layer MoSsub>2sub> in the visible range, broadband atomic-layer MoSsub>2sub> optical modulators for the visible ultrafast pulse generation are developed and selected based on the proposed design criteria for novel two-dimensional (2D) optical modulators. By applying the selected MoSsub>2sub> optical modulators in the solid-state praseodymium lasers, broadband mode-locked ultrafast lasers from 522 to 639 nm are originally realized. We believe that this Letter should promote the development of visible ultrafast photonics and further applications of 2D optoelectronic materials.

  5. New microwave excitation signal generating circuit for quantum frequency standard on the atoms of caesium Cs133

    Science.gov (United States)

    Petrov, A. A.; Davydov, V. V.

    2016-03-01

    In this work the study, design, development and experimental results of a new microwave excitation signal generating circuit are presented. New design of this circuit is based on the method of direct digital synthesis. The results of theoretical calculations and experimental researches show that the new design not only has a high precision, but also has an improvement in the spectral characteristics of the output signal. Range of generated output frequencies is expanded, that leads to the possibility of detuning the frequency of the neighboring resonance of spectral line and adjust the C-field in quantum frequency standard. Experimental research of the metrological characteristics of the quantum frequency standard on the atoms of caesium with a new functional unit showed an improvement in the daily frequency stability.

  6. Comparative investigation of third- and fifth-harmonic generation in atomic and molecular gases driven by midinfrared ultrafast laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Ni Jielei; Yao Jinping; Zeng Bin; Chu Wei; Li Guihua; Zhang Haisu; Jing Chenrui [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 800-211, Shanghai 201800 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Chin, S. L. [Department of Physics, Engineering Physics and Optics, and Center for Optics, Photonics and Laser (COPL), Laval University, Laval, Quebec, G1K 7P4 (Canada); Cheng, Y.; Xu, Z. [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P.O. Box 800-211, Shanghai 201800 (China)

    2011-12-15

    We report on the comparative experimental investigation on third- and fifth-harmonic generation (THG and FHG) in atomic and molecular gases driven by midinfrared ultrafast laser pulses at a wavelength of {approx}1500 nm. We observe that the conversion efficiencies of both the THG and FHG processes saturate at similar peak intensities close to {approx}1.5 x 10{sup 14} W/cm{sup 2} for argon, nitrogen, and air, whose ionization potentials are close to each other. Near the saturation intensity, the ratio of yields of the FHG and THG reaches {approx}10{sup -1} for all the gases. Our results show that high-order Kerr effect seems to exist; however, contribution from the fourth-order Kerr refractive index coefficient alone is insufficient to balance the Kerr self-focusing without the assistance of plasma generation.

  7. White light generation by carbonyl based indole derivatives due to proton transfer: an efficient fluorescence sensor.

    Science.gov (United States)

    Singla, Nidhi; Bhadram, Venkata Srinu; Narayana, Chandrabhas; Chowdhury, Papia

    2013-04-01

    The motivation of the present work is to understand the optical, chemical, and electrical aspects of the proton transfer mechanism of indole (I) and some carbonyl based indole derivatives: indole-3-carboxaldehyde (I3C) and indole-7-carboxaldehyde (I7C) for both powder form and their liquid solution. Structural information for indole derivatives (isolated molecule and in solution) is obtained with density functional theory (DFT) and time dependent DFT (TD-DFT) methods. Calculated transition energies are used to generate UV-vis, FTIR, Raman, and NMR spectra which are later verified with the experimental spectra. The occurrence of different conformers [cis (N(c)), trans (N(t)), and zwitterion (Z*)] have been interpreted by Mulliken charge, natural bond orbital (NBO) analysis, and polarization versus electric field (P-E loop) studies. (1)H and (13)C NMR and molecular vibrational frequencies of the fundamental modes established the stability of Nc due to the presence of intramolecular hydrogen bonding (IHB) in the ground state (S0). Computed/experimental UV-vis absorption/emission studies reveal the creation of new species: zwitterion (Z*) and anion (A*) in the excited state (S1) due to excited state intramolecular and intermolecular proton transfer (ESI(ra)PT and ESI(er)PT). Increased electrical conductivity (σ(ac)) with temperature and increased ferroelectric polarization at higher field verifies proton conduction in I7C.

  8. Synthesis of fluorescent core-shell nanomaterials and strategies to generate white light

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Amandeep; Kaur, Ramanjot [Department of Nanotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib (India); Pandey, O. P. [School of Physics and Materials Science, Thapar University, Patiala 147004 (India); Wei, Xueyong [State Key Laboratory for Manufacturing System Engineering, Xi' an Jiaotong University, 710049 Xi' an (China); Sharma, Manoj, E-mail: manojnarad@gmail.com, E-mail: manojsharma@bilkent.edu.tr [Department of Nanotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib (India); UNAM–Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey)

    2015-07-28

    In this work, cadmium free core-shell ZnS:X/ZnS (X = Mn, Cu) nanoparticles have been synthesized and used for white light generation. First, the doping concentration of Manganese (Mn) was varied from 1% to 4% to optimize the dopant related emission and its optimal value was found to be 1%. Then, ZnS shell was grown over ZnS:Mn(1%) core to passivate the surface defects. Similarly, the optimal concentration of Copper (Cu) was found to be 0.8% in the range varied from 0.6% to 1.2%. In order to obtain an emission in the whole visible spectrum, dual doping of Mn and Cu was done in the core and the shell, respectively. A solid-solid mixing in different ratios of separately doped quantum dots (QDs) emitting in the blue green and the orange region was performed. Results show that the optimum mixture of QDs excited at 300 nm gives Commission Internationale del'Éclairage color coordinates of (0.35, 0.36), high color rendering index of 88, and correlated color temperature of 4704 K with minimum self-absorption.

  9. UV-photochemical vapor generation of selenium for atomic absorption spectrometry: Optimization and 75Se radiotracer efficiency study

    Science.gov (United States)

    Rybínová, Marcela; Musil, Stanislav; Červený, Václav; Vobecký, Miloslav; Rychlovský, Petr

    2016-09-01

    Volatile selenium compounds were generated UV-photochemically in the continuous flow mode using four UV-photoreactors differing in the material of the reaction coil; Teflon tubing and quartz tubes with various inner diameters and wall thicknesses were tested. Atomic absorption spectrometry with an externally heated quartz furnace atomizer was employed as the detector. The relevant experimental generation parameters were optimized and the basic analytical characteristics were determined. Using formic acid as the photochemical agent, limits of detection achieved for selenium were in the range 46-102 ng L- 1 in dependence on the type of UV-photoreactor employed. When nitric acid was also added to the photochemical agent, the limits of detection were reduced to 27-44 ng L- 1. The repeatability did not exceed 2.4% (5 μg L- 1 Se(IV), n = 10). Experiments with 75Se radiotracer have been performed for the first time to quantify the efficiency of UV-photochemical vapor generation (UV-PVG) of selenium. The highest efficiency of 67 ± 1% was obtained for a UV-photoreactor containing a quartz reaction coil (2.0 mm i.d., 4.0 mm o.d.). The generation efficiency of 61 ± 1% was obtained for a Teflon reaction coil (1.0 mm i.d., 1.4 mm o.d.). Mapping of the radiotracer distribution in the individual parts of the apparatus did not reveal substantial transport losses of the analyte in the UV-PVG system.

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

    Science.gov (United States)

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

    2017-08-03

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

  11. Generation of neutral atomic beams utilizing photodetachment by high power diode laser stacks

    Science.gov (United States)

    O'Connor, A. P.; Grussie, F.; Bruhns, H.; de Ruette, N.; Koenning, T. P.; Miller, K. A.; Savin, D. W.; Stützel, J.; Urbain, X.; Kreckel, H.

    2015-11-01

    We demonstrate the use of high power diode laser stacks to photodetach fast hydrogen and carbon anions and produce ground term neutral atomic beams. We achieve photodetachment efficiencies of ˜7.4% for H- at a beam energy of 10 keV and ˜3.7% for C- at 28 keV. The diode laser systems used here operate at 975 nm and 808 nm, respectively, and provide high continuous power levels of up to 2 kW, without the need of additional enhancements like optical cavities. The alignment of the beams is straightforward and operation at constant power levels is very stable, while maintenance is minimal. We present a dedicated photodetachment setup that is suitable to efficiently neutralize the majority of stable negative ions in the periodic table.

  12. Generation of neutral atomic beams utilizing photodetachment by high power diode laser stacks

    CERN Document Server

    O'Connor, A P; Grussie, F; Koenning, T P; Miller, K A; de Ruette, N; Stützel, J; Savin, D W; Urbain, X; Kreckel, H

    2015-01-01

    We demonstrate the use of high power diode laser stacks to photodetach fast hydrogen and carbon anions and produce ground term neutral atomic beams. We achieve photodetachment efficiencies of $\\sim$7.4\\% for H$^-$ at a beam energy of 10\\,keV and $\\sim$3.7\\% for C$^-$ at 28\\,keV. The diode laser systems used here operate at 975\\,nm and 808\\,nm, respectively, and provide high continuous power levels of up to 2\\,kW, without the need of additional enhancements like optical cavities. The alignment of the beams is straightforward and operation at constant power levels is very stable, while maintenance is minimal. We present a dedicated photodetachment setup that is suitable to efficiently neutralize the majority of stable negative ions in the periodic table.

  13. Atomic harmonic generation in time-dependent R-matrix theory

    Science.gov (United States)

    Brown, A. C.; Robinson, D. J.; van der Hart, H. W.

    2012-11-01

    We have developed the capability to determine accurate harmonic spectra for multielectron atoms within time-dependent R-matrix (TDRM) theory. Harmonic spectra can be calculated using the expectation value of the dipole length, velocity, or acceleration operator. We assess the calculation of the harmonic spectrum from He irradiated by 390-nm laser light with intensities up to 4×1014 W cm-2 using each form, including the influence of the multielectron basis used in the TDRM code. The spectra are consistent between the different forms, although the dipole acceleration calculation breaks down at lower harmonics. The results obtained from TDRM theory are compared with results from the helium code, finding good quantitative agreement between the methods. We find that bases which include pseudostates give the best comparison with the helium code, but models comprising only physical orbitals also produce accurate results.

  14. Atomic harmonic generation in time-dependent R-matrix theory

    CERN Document Server

    Brown, A C; van der Hart, H W

    2012-01-01

    We have developed the capability to determine accurate harmonic spectra for multielectron atoms within time-dependent R-matrix (TDRM) theory. Harmonic spectra can be calculated using the expectation value of the dipole length, velocity or acceleration operator. We assess the calculation of the harmonic spectrum from He irradiated by 390 nm laser light with intensities up to 4 x 10(14) W cm(-2) using each form, including the influence of the multielectron basis used in the TDRM code. The spectra are consistent between the different forms, although the dipole acceleration calculation breaks down at lower harmonics. The results obtained from TDRM theory are compared with results from the HELIUM code finding good quantitative agreement between the methods. We find that bases which include pseudostates give the best comparison with the HELIUM code, but models comprising only physical orbitals also produce accurate results.

  15. Determination of lead in wine and rum samples by flow injection-hydride generation-atomic absorption spectrometry.

    Science.gov (United States)

    Elçi, Latif; Arslan, Zikri; Tyson, Julian F

    2009-03-15

    A method for direct determination of lead in wine and rum samples was developed, using a flow injection hydride generation system coupled to an atomic absorption spectrometer with flame-quartz atomizer (FI-HG-AAS). Lead hyride (PbH(4)) was generated using potassium ferricyanide (K(3)Fe(CN)(6)), as oxidant and sodium tetrahydroborate (NaBH(4)) as reductant. Samples were acidified to 0.40% (v/v) HCl for wine and to 0.30% (v/v) HCl for rum, which were then mixed on-line with 3% (m/v) K(3)Fe(CN)(6) solution in 0.03% (v/v) HCl prior to reaction with 0.2% (m/v) alkaline NaBH(4) solution. Lead contents of a rum and two different red wine samples were determined by FI-HG-AAS agreed with those obtained by ICP-MS. The analytical figures of merit of method developed were determined. The calibration curve was linear up to 8.0 microg L(-1) Pb with a regression coefficient of 0.998. The relative error was lower than 4.58%. The relative standard deviation (n=7) was better than 12%. A detection limit of 0.16 microg L(-1) was achieved for a sample volume of 170 microL.

  16. Determination of Trace Germanium in Marine Sediments by Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS)

    Institute of Scientific and Technical Information of China (English)

    LI Jing; ZHAO Shilan; ZHANG Zhaohui; ZENG Xianjie

    2004-01-01

    A method for the analysis of trace germanium in marine sediments by HG-AFS has been investigated. The experimental conditions such as the acidity of reduction reaction, the amount of sodium boro-hydride, the carrier gas flow rate, etc., were tested and optimized by using a kind of orthogonal design. The detection limit of the presented method is 0.95 μg L-1 for germanium. The calibration curve shows a satisfactory line in the concentration range 0-320 μg L-1 Ge with a variation coefficient of ±2.1%.

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

    Science.gov (United States)

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

    2017-01-01

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

  18. Scott correction for large atoms and molecules in a self-generated magnetic field

    DEFF Research Database (Denmark)

    Erdös, Laszlo; Fournais, Søren; Solovej, Jan Philip

    2012-01-01

    We consider a large neutral molecule with total nuclear charge $Z$ in non-relativistic quantum mechanics with a self-generated classical electromagnetic field. To ensure stability, we assume that $Z\\al^2\\le \\kappa_0$ for a sufficiently small $\\kappa_0$, where $\\al$ denotes the fine structure...

  19. Scott correction for large atoms and molecules in a self-generated magnetic field

    DEFF Research Database (Denmark)

    Erdös, Laszlo; Fournais, Søren; Solovej, Jan Philip

    2012-01-01

    We consider a large neutral molecule with total nuclear charge $Z$ in non-relativistic quantum mechanics with a self-generated classical electromagnetic field. To ensure stability, we assume that $Z\\al^2\\le \\kappa_0$ for a sufficiently small $\\kappa_0$, where $\\al$ denotes the fine structure...

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

    Institute of Scientific and Technical Information of China (English)

    徐燕

    2012-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    秦晓鹏; 吴锴; 陶福棠; 李凯

    2013-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    曾正强; 向黎黎; 姚太平

    2012-01-01

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

  3. Determination of the positions of aluminum atoms introduced into SSZ-35 and the catalytic properties of the generated Brønsted acid sites.

    Science.gov (United States)

    Miyaji, Akimitsu; Kimura, Nobuhiro; Shiga, Akinobu; Hayashi, Yoshihiro; Nishitoba, Toshiki; Motokura, Ken; Baba, Toshihide

    2017-03-01

    The positions of aluminum (Al) atoms in SSZ-35 together with the characteristics of the generated protons were investigated by (27)Al multiple quantum magic-angle spinning (MQ-MAS), (29)Si MAS, and (1)H MAS NMR data analyses accompanied by a variable temperature (1)H MAS NMR analysis. The origin of the acidic -OH groups (Brønsted acid sites) generated by introducing Al atoms into the T sites was investigated and the T sites introduced into the Al atoms were revealed. To further determine the catalytic properties of the acidic protons generated in SSZ-35, the influence of the concentration of the Al atoms on the catalytic activity and selectivity during the transformation of toluene was examined.

  4. Evaluation of vapor generation for the determination of nickel by inductively coupled plasma-atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Marrero, Julieta [Comision Nacional de Energia Atomica, Unidad de Actividad Quimica, Centro Atomico Constituyentes, Av. Gral. Paz 1499, 1650-San Martin, Pcia. de Buenos Aires (Argentina); Smichowski, Patricia [Comision Nacional de Energia Atomica, Unidad Proyectos Especiales de Suministros Nucleares, Av. Libertador 8250, 1429-Buenos Aires (Argentina)

    2002-09-01

    Volatile species of Ni were generated by merging acidified aqueous samples and sodium tetrahydroborate(III) in a continuous flow system. The gaseous analyte was subsequently introduced via a stream of Ar carrier into the inlet tube of the plasma torch. Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used for detection. The operating conditions (chemical and physical parameters) and the concentrations of different acids were evaluated for the efficient generation of Ni vapor. The detection limit (3 {sigma}{sub blank}) was 1.8 ng mL{sup -1}. The precision (RSD) of the determination was 4.2% at a level of 500 ng mL{sup -1} and 7.3% for 20 ng mL{sup -1} (n=10). The efficiency of the generation process was estimated to be 51%. The possible interfering effect of transition metals (Cd, Co, Cu, Cr, Fe, Mn, Zn), hydride forming elements (As, Ge, Pb, Sb, Se, Sn, Te), and Hg on Ni signal was examined. This study has demonstrated that Ni vapor generation is markedly free of interferences. (orig.)

  5. Autopsy findings of the first and second filial generations of atomic bomb survivors

    Energy Technology Data Exchange (ETDEWEB)

    Satow, Yukio (Hiroshima Univ. (Japan). Research Inst. for Nuclear Medicine and Biology)

    1992-01-01

    Autopsy findings of 652 fetuses whose parents or one parent were exposed to the Atomic Bomb (F[sub 1]) and 115 fetuses which had one or two grandparents exposed (F[sub 2]) were compared with that of 8570 fetuses whose parents were not exposed (control). The F[sub 1] fetuses have been collected since 1963 and F[sub 2] fetuses since 1971 voluntarily in Hiroshima. The findings were classified according to the types of delivery and to the distances away from the hypocenter where the parents and grandparents were exposed. Many normal cases in the group of artificial abortions and many malformations and pathological findings in the group of spontaneous abortions were found in both groups of F[sub 1] and F[sub 2]. The malformations were cardiovascular, central nervous and urogenital system, quantitatively in that order, in both groups of F[sub 1] and F[sub 2]. Although there were a few cases of cystic kidney and chondrodystrophy which belong to autosomal dominant and osteogenesis imperfecta which belong to autosomal recessive, these cases were not correlated with the distance. Most cases of malformation which belong to the multifactorial inheritance were found in each organ. No peculiar malformation was found in the groups of F[sub 1] and F[sub 2]. (author).

  6. Ultrafast atomic-scale visualization of acoustic phonons generated by optically excited quantum dots

    Directory of Open Access Journals (Sweden)

    Giovanni M. Vanacore

    2017-07-01

    Full Text Available Understanding the dynamics of atomic vibrations confined in quasi-zero dimensional systems is crucial from both a fundamental point-of-view and a technological perspective. Using ultrafast electron diffraction, we monitored the lattice dynamics of GaAs quantum dots—grown by Droplet Epitaxy on AlGaAs—with sub-picosecond and sub-picometer resolutions. An ultrafast laser pulse nearly resonantly excites a confined exciton, which efficiently couples to high-energy acoustic phonons through the deformation potential mechanism. The transient behavior of the measured diffraction pattern reveals the nonequilibrium phonon dynamics both within the dots and in the region surrounding them. The experimental results are interpreted within the theoretical framework of a non-Markovian decoherence, according to which the optical excitation creates a localized polaron within the dot and a travelling phonon wavepacket that leaves the dot at the speed of sound. These findings indicate that integration of a phononic emitter in opto-electronic devices based on quantum dots for controlled communication processes can be fundamentally feasible.

  7. Determination of Phosphorus by Inductively Coupled Plasma Atomic Emission Spectroscopy after Hydride Generation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A continuous phosphine (PH3) generation was developed and applied to the sensitive detection of phosphorus by ICP-AES. Phosphate ion in aqueous solution was converted to phosphine by passing the sample solution through an incandescent copper silica-tube. Detection limit is 2 ng/mL. The relative standard deviation is 4.2% for 20 ng/mL. The method is rapid and simple with low contamination and high sensitivity.

  8. 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%.

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

    Institute of Scientific and Technical Information of China (English)

    顾志勇

    2014-01-01

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

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

    Science.gov (United States)

    Daye, Mirna; Halwani, Jalal; Hamzeh, Mariam

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Mirna Daye

    2013-01-01

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

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

    Science.gov (United States)

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

    2017-07-01

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

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

    Science.gov (United States)

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

    2015-03-01

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

  14. CHARACTERIZATION OF SALT PARTICLE INDUCED CORROSION PROCESSES BY SYNCHROTRON GENERATED X-RAY FLUORESCENCE AND COMPLEMENTARY SURFACE ANALYSIS TOOLS.

    Energy Technology Data Exchange (ETDEWEB)

    NEUFELD, A.K.; COLE, I.S.; BOND, A.M.; ISAACS, H.S.; FURMAN, S.A.

    2001-03-25

    The benefits of using synchrotron-generated X-rays and X-ray fluorescence analysis in combination with other surface analysis techniques have been demonstrated. In studies of salt-induced corrosion, for example, the detection of Rb ions in the area of secondary spreading when salt-containing micro-droplets are placed on zinc surfaces, further supports a mechanism involving cation transport during the corrosion and spreading of corrosive salt on exposed metal surfaces. Specifically, the new analytical data shows that: (a) cations are transported radially from a primary drop formed from a salt deposit in a thin film of secondary spreading around the drop; (b) subsequently, micro-pools are formed in the area of secondary spreading, and it is likely that cations transported within the thin film accumulate in these micro-pools until the area is dehydrated; (c) the mechanism of cation transport into the area of secondary spreading does not include transport of the anions; and (d) hydroxide is the counter ion formed from oxygen reduction at the metal surface within the spreading layer. Data relevant to iron corrosion is also presented and the distinct differences relative to the zinc situation are discussed.

  15. An Aluminum Microfluidic Chip Fabrication Using a Convenient Micromilling Process for Fluorescent Poly(DL-lactide-co-glycolide Microparticle Generation

    Directory of Open Access Journals (Sweden)

    Wan-Chen Hsieh

    2012-02-01

    Full Text Available This study presents the development of a robust aluminum-based microfluidic chip fabricated by conventional mechanical micromachining (computer numerical control-based micro-milling process. It applied the aluminum-based microfluidic chip to form poly(lactic-co-glycolic acid (PLGA microparticles encapsulating CdSe/ZnS quantum dots (QDs. A cross-flow design and flow-focusing system were employed to control the oil-in-water (o/w emulsification to ensure the generation of uniformly-sized droplets. The size of the droplets could be tuned by adjusting the flow rates of the water and oil phases. The proposed microfluidic platform is easy to fabricate, set up, organize as well as program, and is valuable for further applications under harsh reaction conditions (high temperature and/or strong organic solvent systems. The proposed method has the advantages of actively controlling the droplet diameter, with a narrow size distribution, good sphericity, as well as being a simple process with a high throughput. In addition to the fluorescent PLGA microparticles in this study, this approach can also be applied to many applications in the pharmaceutical and biomedical area.

  16. Schemes generating entangled states and entanglement swapping between photons and three-level atoms inside optical cavities for quantum communication

    Science.gov (United States)

    Heo, Jino; Kang, Min-Sung; Hong, Chang-Ho; Yang, Hyeon; Choi, Seong-Gon

    2017-01-01

    We propose quantum information processing schemes based on cavity quantum electrodynamics (QED) for quantum communication. First, to generate entangled states (Bell and Greenberger-Horne-Zeilinger [GHZ] states) between flying photons and three-level atoms inside optical cavities, we utilize a controlled phase flip (CPF) gate that can be implemented via cavity QED). Subsequently, we present an entanglement swapping scheme that can be realized using single-qubit measurements and CPF gates via optical cavities. These schemes can be directly applied to construct an entanglement channel for a communication system between two users. Consequently, it is possible for the trust center, having quantum nodes, to accomplish the linked channel (entanglement channel) between the two separate long-distance users via the distribution of Bell states and entanglement swapping. Furthermore, in our schemes, the main physical component is the CPF gate between the photons and the three-level atoms in cavity QED, which is feasible in practice. Thus, our schemes can be experimentally realized with current technology.

  17. Prejudice and Health Anxiety about Radiation Exposure from Second-Generation Atomic Bomb Survivors: Results from a Qualitative Interview Study.

    Science.gov (United States)

    Kamite, Yuka

    2017-01-01

    The effect of atomic bomb radiation exposure on the survivors and their children has been a worrisome problem since soon after the 1945 Hiroshima and Nagasaki bombings. Researchers have examined physical and genetic effects; however, no research has focused on second-generation survivors' (SGS) psychological effects. Consequently, this study shed light on the SGS' experience of discrimination and prejudice and their anxiety concerning the genetic effects of radiation exposure. This study utilized semi-structured interviews with 14 SGS (10 women, mean age = 56 ± 6.25 years, range = 46-68 years). Data were analyzed using a modified version of the grounded theory approach. Three categories were extracted: low awareness as an SGS, no health anxiety regarding the effect of radiation, and health anxiety regarding the effect of radiation. The results did not reveal that SGS who grew up in the bombed areas experienced discrimination or prejudice. They had little health anxiety from childhood to adolescence. In this study, some of the SGS developed health anxiety about their third-generation children, but only among female participants. Perhaps the transgenerational transmission of anxiety concerning the genetic effects of radiation exposure causes stress, particularly among women with children. However, a change was seen in adulthood health anxiety regarding the effects of radiation, suggesting the possibility that changes in the psychological experiences of SGS can be observed throughout their lifetimes and that their own health status, and that of their children, the third-generation survivors, affects their health anxiety regarding radiation.

  18. Prejudice and Health Anxiety about Radiation Exposure from Second-Generation Atomic Bomb Survivors: Results from a Qualitative Interview Study

    Directory of Open Access Journals (Sweden)

    Yuka Kamite

    2017-08-01

    Full Text Available The effect of atomic bomb radiation exposure on the survivors and their children has been a worrisome problem since soon after the 1945 Hiroshima and Nagasaki bombings. Researchers have examined physical and genetic effects; however, no research has focused on second-generation survivors’ (SGS psychological effects. Consequently, this study shed light on the SGS’ experience of discrimination and prejudice and their anxiety concerning the genetic effects of radiation exposure. This study utilized semi-structured interviews with 14 SGS (10 women, mean age = 56 ± 6.25 years, range = 46–68 years. Data were analyzed using a modified version of the grounded theory approach. Three categories were extracted: low awareness as an SGS, no health anxiety regarding the effect of radiation, and health anxiety regarding the effect of radiation. The results did not reveal that SGS who grew up in the bombed areas experienced discrimination or prejudice. They had little health anxiety from childhood to adolescence. In this study, some of the SGS developed health anxiety about their third-generation children, but only among female participants. Perhaps the transgenerational transmission of anxiety concerning the genetic effects of radiation exposure causes stress, particularly among women with children. However, a change was seen in adulthood health anxiety regarding the effects of radiation, suggesting the possibility that changes in the psychological experiences of SGS can be observed throughout their lifetimes and that their own health status, and that of their children, the third-generation survivors, affects their health anxiety regarding radiation.

  19. The bungling giant : Atomic Energy Canada Limited and next-generation nuclear technology, 1980-1994

    Energy Technology Data Exchange (ETDEWEB)

    Slater, I.J

    2003-07-01

    From 1980-1994 Atomic Energy Canada Limited (AECL), the Crown Corporation responsible for the development of nuclear technology in Canada, ventured into the market for small-scale, decentralized power systems with the Slowpoke Energy System (SES), a 10MW nuclear reactor for space heating in urban and remote areas. The SES was designed to be 'passively' or 'inherently' safe, such that even the most catastrophic failure of the system would not result in a serious accident (e.g. a meltdown or an explosion). This Canadian initiative, a beneficiary of the National Energy Program, was the first and by far the most successful attempt at a passively safe, decentralized nuclear power system anywhere in the world. Part one uses archival documentation and interviews with project leaders to reconstruct the history of the SES. The standard explanations for the failure of the project, cheap oil, public resistance to the technology, and lack of commercial expertise, are rejected. Part two presents an alternative explanation for the failure of AECL to commercialize the SES. In short, technological momentum towards large-scale nuclear designs led to structural restrictions for the SES project. These restrictions manifested themselves internally to the company (e.g., marginalization of the SES) and externally to the company (e.g., licensing). In part three, the historical lessons of the SES are used to refine one of the central tenets of Popper's political philosophy, 'piecemeal social engineering.' Popper's presentation of the idea is lacking in detail; the analysis of the SES provides some empirical grounding for the concept. I argue that the institutions surrounding traditional nuclear power represent a form utopian social engineering, leading to consequences such as the suspension of civil liberties to guarantee security of the technology. The SES project was an example of a move from the utopian social engineering of large

  20. Evaluation of arsenic and selenium in Brazilian soluble coffee by inductively coupled plasma atomic emission spectrometry with hydride generation

    Directory of Open Access Journals (Sweden)

    Santos Éder José dos

    2001-01-01

    Full Text Available A method for the evaluation of arsenic and selenium in soluble coffee by inductively coupled plasma atomic emission spectrometry with continuous hydride generation to attend the Brazilian food legislation is described. Samples were digested with nitric acid and hydrogen peroxide in a focused microwave system. Slow heating eliminated nitric acid and selenium (VI was reduced to selenium (IV by addition of 6 mol/L hydrochloric acid and heating at 90° C under a reflux system. The influence of sample acidity on sensitivity was investigated. Hydrochloric acid 6 mol/L was the most suitable reaction medium. Practical detection limits of 2.0mug/L for As and 1.0mu g/L for Se were achieved and attended the Brazilian food legislation. The results of recoveries on spiked samples demonstrate the reliability and accuracy of the procedure.

  1. Design and evaluation of a continuous flow, integrated nebulizer-hydride generator for flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Miguel Murillo

    2008-01-01

    Full Text Available An evaluation of the performance of a continuous flow hydride generator-nebulizer for flame atomic absorption spectrometry was carried out. Optimization of nebulizer gas flow rate, sample acid concentration, sample and tetrahydroborate uptake rates and reductant concentration, on the As and Se absorbance signals was carried out. A hydrogen-argon flame was used. An improvement of the analytical sensitivity relative to the conventional bead nebulizer used in flame AA was obtained (2 (As and 4.8 (Se µg L-1. Detection limits (3σb of 1 (As and 1.3 (Se µg L-1 were obtained. Accuracy of the method was checked by analyzing an oyster tissue reference material.

  2. Influence of Virtual Photon Process on the Generation of Squeezed Light from Atoms in an Optical Cavity

    Directory of Open Access Journals (Sweden)

    Aranya B. Bhattacherjee

    2015-07-01

    Full Text Available We show that a collection of two-level atoms in an optical cavity beyond the rotating wave approximation and in the dispersive-adiabatic and non-dispersive adiabatic regime constitutes a nonlinear medium and is capable of generating squeezed state of light. It is found that squeezing produced in the non-dispersive adiabatic regime is significantly high compared to that produced in the dispersive-adiabatic limit. On the other hand, we also show that it could be possible to observe the Dicke superradiant quantum phase transition in the dispersive-adiabatic regime where the Ã2 term is negligible. Such a system can be an essential component of a larger quantum-communication system.

  3. Synthesis with Perfect Atom Economy: Generation of Furan Derivatives by 1,3-Dipolar Cycloaddition of Acetylenedicarboxylates at Cyclooctynes

    Directory of Open Access Journals (Sweden)

    Klaus Banert

    2014-09-01

    Full Text Available Cyclooctyne and cycloocten-5-yne undergo, at room temperature, a 1,3-dipolar cycloaddition with dialkyl acetylenedicarboxylates 1a,b to generate furan-derived short-lived intermediates 2, which can be trapped by two additional equivalents of 1a,b or alternatively by methanol, phenol, water or aldehydes to yield polycyclic products 3b–d, orthoesters 4a–c, ketones 5 or epoxides 6a,b, respectively. Treatment of bis(trimethylsilyl acetylenedicarboxylate (1c with cyclooctyne leads to the ketone 7 via retro-Brook rearrangement of the dipolar intermediate 2c. In all cases, the products are formed with perfect atom economy.

  4. Absorption-amplification response with or without spontaneously generated coherence effect in a four-level atomic system

    Institute of Scientific and Technical Information of China (English)

    Jiahua Li(李家华); Wenxing Yang(杨文星); Jucun Peng(彭菊村)

    2004-01-01

    We discuss and analyze the absorption properties of a weak probe field in a typical four-level atomic system in the presence of a spontaneously generated coherence (SGC) term. The influences of the SGC and a coherent pump field on the probe absorption-amplification are investigated. The results show that the absorption of such a weak probe field can be dramatically enhanced due to the SGC effect. At the same time, the probe-absorption profile exhibits a two-peak structure and the probe-absorption peak gradually decreases as the pump intensity increases. On the contrary, the amplification of such a weak probe field near the line center of the probe transition can be achieved by adjusting the coherent pump field intensity in the absence of the SGC effect.

  5. Activators generated by electron transfer for atom transfer radical polymerization of styrene in the presence of mesoporous silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Khezri, Khezrollah, E-mail: kh.khezri@ut.ac.ir [School of Chemistry, University College of Science, University of Tehran, PO Box 14155-6455, Tehran (Iran, Islamic Republic of); Roghani-Mamaqani, Hossein [Department of Polymer Engineering, Sahand University of Technology, PO Box 51335-1996, Tabriz (Iran, Islamic Republic of)

    2014-11-15

    Graphical abstract: Effect of mesoporous silica nanoparticles (MCM-41) on the activator generated by electron transfer for atom transfer radical polymerization (AGET ATRP) is investigated. Decrement of conversion and number average molecular weight and also increment of polydispersity index (PDI) values are three main results of addition of MCM-41 nanoparticles. Incorporation of MCM-41 nanoparticles in the polystyrene matrix can clearly increase thermal stability and decrease glass transition temperature of the nanocomposites. - Highlights: • Spherical morphology, hexagonal structure, and high surface area with regular pore diameters of the synthesized MCM-41 nanoparticles are examined. • AGET ATRP of styrene in the presence of MCM-41 nanoparticles is performed. • Effect of MCM-41 nanoparticles addition on the polymerization rate, conversion and molecular weights of the products are discussed. • Improvement in thermal stability of the nanocomposites and decreasing T{sub g} values was also observed by incorporation of MCM-41 nanoparticles. - Abstract: Activator generated by electron transfer for atom transfer radical polymerization was employed to synthesize well-defined mesoporous silica nanoparticles/polystyrene composites. Inherent features of spherical mesoporous silica nanoparticles were evaluated by nitrogen adsorption/desorption isotherm, X-ray diffraction and scanning electron microscopy analysis techniques. Conversion and molecular weight evaluations were carried out using gas and size exclusion chromatography respectively. By the addition of only 3 wt% mesoporous silica nanoparticles, conversion decreases from 81 to 58%. Similarly, number average molecular weight decreases from 17,116 to 12,798 g mol{sup −1}. However, polydispersity index (PDI) values increases from 1.24 to 1.58. A peak around 4.1–4.2 ppm at proton nuclear magnetic resonance spectroscopy results clearly confirms the living nature of the polymerization. Thermogravimetric

  6. Determination of total arsenic content in water by atomic absorption spectroscopy (AAS) using vapour generation assembly (VGA).

    Science.gov (United States)

    Behari, Jai Raj; Prakash, Rajiv

    2006-03-01

    Analysis of arsenic in water is important in view of contamination of ground water with arsenic in some parts of the world including West Bengal in India and neighboring country Bangladesh. WHO has fixed the threshold for arsenic in drinking water to 10ppb (microg/l) level, hence the methodology for determination of arsenic is required to be sensitive at ppb level. Atomic absorption spectrophotometry with vapour generation assembly (AAS-VGA) is well known technique for the trace analysis of arsenic. However, total arsenic analysis [As(III)+As(V)] is very crucial and it requires reduction of As(V) to As(III) for correct analysis. As(III) is reduced to AsH3 vapours and finally to free As atoms, which are responsible for absorption signal in AAS. To accomplish this the vapour generation assembly attached to AAS has acid channel filled with 10 M HCl and the reduction channel with sodium borohydride. Further sample can be reduced either before aspiration for analysis, using potassium iodide (KI) or the sample can be introduced in the instrument directly and KI can be added in the reduction channel along with the sodium borohydride. The present work shows that samples prepared in 3 M HCl can be reduced with KI for 30 min before introduction in the instrument. Alternatively samples can be prepared in 6 M HCl and directly aspirated in AAS using KI in VGA reduction channel. The latter methodology is more useful when the sample size is large and time cycle is difficult to maintain. It is observed that the acid concentration of the sample in both the situations plays an important role. Further reduction in acid concentration and analysis time is achieved for the arsenic analysis by using modified method. Analysis in both the methods is sensitive at ppb level.

  7. On the thermodynamic efficiency of a multiferroic thermomagnetic generator: From bulk to atomic scale

    Science.gov (United States)

    Sandoval, Samuel Mancilla

    A unique multiferroic type of thermomagnetic generator is being investigated in order to establish its thermodynamic efficiency at different size scales. This device generates electricity when a magnetic material interacts with a thermal gradient by means of a spring-magnet mechanism. This unique technology is compared to other thermal-electric energy harvesting technologies to show that these devices have a similar goal of achieving a maximum theoretical efficiency of around 50% relative to Carnot. The first approach towards achieving improved performance relies on the analytical modeling, and experimental verification, of several subsystems stemming from the original design, which include the optimization of the magnetic force component, the optimization of the heat transfer process and the efficiency of the energy conversion process. The method to improve the magnetic force component is not recommended and neither is the method to improve the heat transfer process. Nevertheless, the energy conversion subsystem is successfully modeled and verified; thereby suggesting that an electromagnetic induction coil may be better suited for the energy conversion process over a ferroelectric transduction mechanism at bulk scale. A cascade design is also investigated as a method to improve device efficiency; though analysis reveals a design flaw, which leads to other methods for improving efficiency. Two models of thermomagnetic generator thermodynamic efficiency are developed, which are based on distinct approaches taken by Solomon and Brillouin in order to compare this unique system to a Carnot engine. The model based on a modified form of Solomon's approach results in a relative efficiency of 0.5%, which compares well with an estimate of efficiency based on provided data from the original design. This representative model of efficiency was then applied to a survey of pure elements for comparison, which confirms gadolinium as the best material for use as a working body with

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

    Science.gov (United States)

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

    1993-02-01

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

  9. Spatial position scaling on harmonic generation from He atom in bowtie-shaped nanostructure

    Science.gov (United States)

    Liu, Hang; Feng, Liqiang; Li, Wenliang; Li, Yi

    2017-09-01

    Spatial position scaling on the harmonic generation from He in the bowtie-shaped nanostructure has been theoretically investigated. It shows that (i) due to the surface plasmon polaritons in the nanostructure, the laser intensity can be enhanced and presents the nonhomogeneous effect in space. As a result, the extension of the harmonic cutoff can be achieved when He is away from the gap center of the nanostructure. However, due to the limit of the gap size, there is a maximum harmonic cutoff extension for a given nanostructure. (ii) Due to the asymmetric enhancement of the laser intensity in space, the extended harmonics are mainly from E(t) >0 a.u. and E(t) <0 a.u. when He is injected into the positive and the negative positions, respectively. Moreover, the intensities and the cutoffs of the extended harmonics can be controlled by changing the pulse duration or by adding the second controlling pulse. Finally, by properly superposing the harmonics from the two-color field, four single attosecond pulses with the durations of 30 as can be produced.

  10. New generation polyphase resonant converter-modulators for the Korean atomic energy research institute

    Energy Technology Data Exchange (ETDEWEB)

    Reass, William A [Los Alamos National Laboratory; Baca, David M [Los Alamos National Laboratory; Gribble, Robert F [Los Alamos National Laboratory

    2009-01-01

    This paper will present operational data and performance parameters of the newest generation polyphase resonant high voltage converter modulator (HVCM) as developed and delivered to the KAERI 100 MeV ''PEFP'' accelerator [1]. The KAERI design realizes improvements from the SNS and SLAC designs [2]. To improve the IGBT switching performance at 20 kHz for the KAERI system, the HVCM utilizes the typical zero-voltage-switching (ZVS) at turn on and as well as artificial zero-current-switching (ZCS) at turn-off. The new technique of artificial ZCS technique should result in a 6 fold reduction of IGBT switching losses (3). This improves the HCVM conversion efficiency to better than 95% at full average power, which is 500 kW for the KAERI two klystron 105 kV, 50 A application. The artificial ZCS is accomplished by placing a resonant RLC circuit across the input busswork to the resonant boost transformer. This secondary resonant circuit provides a damped ''kick-back'' to assist in IGBT commutation. As the transformer input busswork is extremely low inductance (< 10 nH), the single RLC network acts like it is across each of the four IGBT collector-emitter terminals of the H-bridge switching network. We will review these topological improvements and the overall system as delivered to the KAERI accelerator and provide details of the operational results.

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

    Institute of Scientific and Technical Information of China (English)

    韩雪飞

    2016-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    骆胜超; 李皓

    2011-01-01

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

  13. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-05-19

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

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

    Science.gov (United States)

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

    2009-05-01

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

  16. 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)

  17. Third harmonic generation in isolated all dielectric meta-atoms (Conference Presentation)

    Science.gov (United States)

    Melik-Gaykazyan, Elizaveta V.; Shorokhov, Alexander S.; Shcherbakov, Maxim R.; Staude, Isabelle; Smirnova, Daria A.; Miroshnichenko, Andrey E.; Brener, Igal; Neshev, Dragomir N.; Fedyanin, Andrey A.; Kivshar, Yuri S.

    2016-04-01

    Two series of nanodisk arrays were designed. The first one was fabricated out of a silicon-on-insulator (SOI) wafer using electron-beam lithography and a reactive-ion etching process. The top layer of a SOI wafer is a 260-nm layer of monocrystalline (100)-cut silicon. We consider three square 400x400 μm2 arrays distinguished by the disk diameter values - 340, 345 and 360 nm, respectively; the period of the nanodisk ordering in the array amounted to 2.85 μm - this value allows for regarding the disks as isolated ones in terms of optical coupling. The nanodisk diameter choice specifies the magnetic dipolar (MD) resonance wavelength [1]. The second series of arrays was made of a 130-nm hydrogenated amorphous silicon (a-Si:H) film grown by plasma-enhanced chemical vapor deposition on a thin glass substrate. In order to study the nonlinear optical response of the nanodisks and verify the multipole resonances roles, we conducted third-harmonic generation (THG) spectroscopy measurements using a tunable (1.0-1.5 μm) optical parametric oscillator (200 fs pulses with the repetition rate of 76 MHz) pumped by a Ti:Sapphire laser. The laser beam waist diameter was set at 11 μm by an aspheric lens. The full thickness of both the SOI and glass wafers (˜500 μm each) was less than the waist depth. The resulting peak intensity reached the values of about 1 GW/cm2 in the sample plane. The laser beam polarization was linear as controlled by a Glan-Taylor laser prism. The transmitted and collimated THG signal was selected by a set of blue filters and detected by a photomultiplier tube connected with a lock-in amplifier. This signal was proven to be of TH origin by checking its cubic dependence on the pump power and by direct measurements of its spectrum. It was also verified that the THG beam was polarized parallel to the orientation of the pump beam polarization. It should be pointed out that the penetration depth of the THG into silicon does not exceed the nanodisk height. The

  18. Harmonic generation by noble-gas atoms in the near-IR regime using ab initio time-dependent R -matrix theory

    Science.gov (United States)

    Hassouneh, O.; Brown, A. C.; van der Hart, H. W.

    2014-10-01

    We demonstrate the capability of ab initio time-dependent R -matrix theory to obtain accurate harmonic generation spectra of noble-gas atoms at near-IR wavelengths between 1200 and 1800 nm and peak intensities up to 1.8 × 10 14 W /cm 2. To accommodate the excursion length of the ejected electron, we use an angular-momentum expansion up to Lmax=279 . The harmonic spectra show evidence of atomic structure through the presence of a Cooper minimum in harmonic generation for Kr, and of multielectron interaction through the giant resonance for Xe. The theoretical spectra agree well with those obtained experimentally.

  19. Harmonic generation of noble-gas atoms in the Near-IR regime using ab-initio time-dependent R-matrix theory

    CERN Document Server

    Hassouneh, O; van der Hart, H W

    2014-01-01

    We demonstrate the capability of ab-initio time-dependent R-matrix theory to obtain accurate harmonic generation spectra of noble-gas atoms at Near-IR wavelengths between 1200 and 1800 nm and peak intensities up to 1.8 X 10(14) W/cm(2) . To accommodate the excursion length of the ejected electron, we use an angular-momentum expansion up to Lmax = 279. The harmonic spectra show evidence of atomic structure through the presence of a Cooper minimum in harmonic generation for Kr, and of multielectron interaction through the giant resonance for Xe. The theoretical spectra agree well with those obtained experimentally.

  20. Defect-free atom arrays on demand

    Science.gov (United States)

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

    2016-05-01

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

  1. Generation of a cold pulsed beam of Rb atoms by transfer from a 3D magneto-optic trap

    CERN Document Server

    Chanu, Sapam Ranjita; Natarajan, Vasant

    2016-01-01

    We demonstrate a technique for producing a cold pulsed beam of atoms by transferring a cloud of atoms trapped in a three dimensional magneto-optic trap (MOT). The MOT is loaded by heating a getter source of Rb atoms. We show that it is advantageous to transfer with two beams (with a small angle between them) compared to a single beam, because the atoms stop interacting with the beams in the two-beam technique, which results in a Gaussian velocity distribution. The atoms are further cooled in optical molasses by turning off the MOT magnetic field before the transfer beams are turned on.

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

    Institute of Scientific and Technical Information of China (English)

    李淑娜

    2012-01-01

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

  3. Determination of total arsenic in coal and wood using oxygen flask combustion method followed by hydride generation atomic absorption spectrometry.

    Science.gov (United States)

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

    2010-04-15

    A simple and sensitive procedure for the determination of total arsenic in coal and wood was conducted by use of oxygen flask combustion (OFC) followed by hydride generation atomic absorption spectrometry (HGAAS). The effect of various items (composition of absorbent, standing time between the combustion and filtration, particle size and mass of sample) was investigated. Under the optimized conditions of the OFC method, nine certified reference materials were analyzed, and the values of arsenic concentration obtained by this method were in good accordance with the certified values. The limit of detection (LOD) and relative standard deviation (RSD) of the method were 0.29 microg g(-1) and less than 8%, respectively. In addition, eight kinds of coals and four chromated copper arsenate (CCA)-treated wood wastes were analyzed by the present method, and the data were compared to those from the microwave-acid digestion (MW-AD) method. The determination of arsenic in solid samples was discussed in terms of applicable scope and concentration range of arsenic.

  4. Determination of total arsenic in fish by hydride-generation atomic absorption spectrometry: method validation, traceability and uncertainty evaluation

    Science.gov (United States)

    Nugraha, W. C.; Elishian, C.; Ketrin, R.

    2017-03-01

    Fish containing arsenic compound is one of the important indicators of arsenic contamination in water monitoring. The high level of arsenic in fish is due to absorption through food chain and accumulated in their habitat. Hydride generation (HG) coupled with atomic absorption spectrometric (AAS) detection is one of the most popular techniques employed for arsenic determination in a variety of matrices including fish. This study aimed to develop a method for the determination of total arsenic in fish by HG-AAS. The method for sample preparation from American of Analytical Chemistry (AOAC) Method 999.10-2005 was adopted for acid digestion using microwave digestion system and AOAC Method 986.15 - 2005 for dry ashing. The method was developed and validated using Certified Reference Material DORM 3 Fish Protein for trace metals for ensuring the accuracy and the traceability of the results. The sources of uncertainty of the method were also evaluated. By using the method, it was found that the total arsenic concentration in the fish was 45.6 ± 1.22 mg.Kg-1 with a coverage factor of equal to 2 at 95% of confidence level. Evaluation of uncertainty was highly influenced by the calibration curve. This result was also traceable to International Standard System through analysis of Certified Reference Material DORM 3 with 97.5% of recovery. In summary, it showed that method of preparation and HG-AAS technique for total arsenic determination in fish were valid and reliable.

  5. Brilliant molecular nanocrystals emerging from sol-gel thin films: towards a new generation of fluorescent biochips

    Energy Technology Data Exchange (ETDEWEB)

    Dubuisson, E; Monnier, V; Sanz-Menez, N; Ibanez, A [Institut Neel, CNRS and Universite Joseph Fourier, UPR 2940, BP166, F-38042 Grenoble Cedex 9 (France); Boury, B [Universite Montpellier 2, Departement de Chimie, Institut Charles Gerhardt, UMR 5253 CNRS, cc 1701, Place E Bataillon, F-34095 Montpellier Cedex 5 (France); Usson, Y [TIMC-IMAG, UMR 5525 CNRS, Universite Joseph Fourier, Domaine de la Merci, F-38706 La Tronche Cedex (France); Pansu, R B, E-mail: alain.ibanez@grenoble.cnrs.f [Laboratoire de Photophysique et de Photochimie Supramoleculaire et Macromoleculaire, CNRS, UMR 8531, ENS Cachan, F-94235 Cachan Cedex (France)

    2009-08-05

    To develop highly sensitive biosensors, we made directly available to biological aqueous solutions organic nanocrystals previously grown in the pores of sol-gel films. Through the controlled dissolution of the sol-gel surface, we obtained emerging nanocrystals that remained strongly anchored to the sol-gel coating for good mechanical stability of the final sensing device. We demonstrated that in the presence of a solution of DNA functionalized with a molecular probe, the nanocrystal fluorescence is strongly quenched by Foerster resonance energy transfer thus opening the way towards very sensitive fluorescent biosensors through biomolecules grafted onto fluorescent nanocrystals. Finally, this controlled dissolution, involving weak concentrated NaOH solution, is a generic process that can be used for the thinning of any kind of sol-gel layer.

  6. 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.

  7. Determination of copper in airborne particulate matter using slurry sampling and chemical vapor generation atomic absorption spectrometry.

    Science.gov (United States)

    Silva, Laiana O B; Leao, Danilo J; dos Santos, Debora C; Matos, Geraldo D; de Andrade, Jailson B; Ferreira, Sergio L C

    2014-09-01

    The present paper describes the development of a method for the determination of copper in airborne particulate matter using slurry sampling and chemical vapor generation atomic absorption spectrometry (CVG AAS). Chemometric tools were employed to characterize the influence of several factors on the generation of volatile copper species. First, a two-level full factorial design was performed that included the following chemical variables: hydrochloric acid concentration, tetrahydroborate concentration, sulfanilamide concentration and tetrahydroborate volume, using absorbance as the response. Under the established experimental conditions, the hydrochloric acid concentration had the greatest influence on the generation of volatile copper species. Subsequently, a Box-Behnken design was performed to determine the optimum conditions for these parameters. A second chemometric study employing a two-level full factorial design was performed to evaluate the following physical factors: tetrahydroborate flow rate, flame composition, alcohol volume and sample volume. The results of this study demonstrated that the tetrahydroborate flow rate was critical for the process. The chemometric experiments determined the following experimental conditions for the method: hydrochloric acid concentration, 0.208 M; tetrahydroborate concentration, 4.59%; sulfanilamide concentration, 0.79%; tetrahydroborate volume, 2.50 mL; tetrahydroborate flow rate, 6.50 mL min(-1); alcohol volume, 200 µL; and sample volume, 7.0 mL. Thus, this method, using a slurry volume of 500 µL and a final dilution of 7 mL, allowed for the determination of copper with limits of detection and quantification of 0.30 and 0.99 µg L(-1), respectively. Precisions, expressed as RSD%, of 4.6 and 2.8% were obtained using copper solutions at concentrations of 5.0 and 50.0 µg L(-1), respectively. The accuracy was evaluated by the analysis of a certified reference material of urban particulate matter. The copper concentration

  8. Rapid Generation of Marker-Free P. falciparum Fluorescent Reporter Lines Using Modified CRISPR/Cas9 Constructs and Selection Protocol

    Science.gov (United States)

    Mogollon, Catherin Marin; van Pul, Fiona J. A.; Imai, Takashi; Ramesar, Jai; Chevalley-Maurel, Séverine; de Roo, Guido M.; Veld, Sabrina A. J.; Kroeze, Hans; Franke-Fayard, Blandine M. D.; Janse, Chris J.

    2016-01-01

    The CRISPR/Cas9 system is a powerful genome editing technique employed in a wide variety of organisms including recently the human malaria parasite, P. falciparum. Here we report on further improvements to the CRISPR/Cas9 transfection constructs and selection protocol to more rapidly modify the P. falciparum genome and to introduce transgenes into the parasite genome without the inclusion of drug-selectable marker genes. This method was used to stably integrate the gene encoding GFP into the P. falciparum genome under the control of promoters of three different Plasmodium genes (calmodulin, gapdh and hsp70). These genes were selected as they are highly transcribed in blood stages. We show that the three reporter parasite lines generated in this study (GFP@cam, GFP@gapdh and GFP@hsp70) have in vitro blood stage growth kinetics and drug-sensitivity profiles comparable to the parental P. falciparum (NF54) wild-type line. Both asexual and sexual blood stages of the three reporter lines expressed GFP-fluorescence with GFP@hsp70 having the highest fluorescent intensity in schizont stages as shown by flow cytometry analysis of GFP-fluorescence intensity. The improved CRISPR/Cas9 constructs/protocol will aid in the rapid generation of transgenic and modified P. falciparum parasites, including those expressing different reporters proteins under different (stage specific) promoters. PMID:27997583

  9. Determination of plutonium in nitric acid solutions using energy dispersive L X-ray fluorescence with a low power X-ray generator

    Energy Technology Data Exchange (ETDEWEB)

    Py, J. [Laboratoire Chrono-Environnement, UMR CNRS 6249, Université de Franche-Comté, 16 route de Gray, F-25030 Besançon (France); Commissariat à l’Énergie Atomique, Centre de Valduc, F-21120 Is-sur-Tille (France); Groetz, J.-E., E-mail: jegroetz@univ-fcomte.fr [Laboratoire Chrono-Environnement, UMR CNRS 6249, Université de Franche-Comté, 16 route de Gray, F-25030 Besançon (France); Hubinois, J.-C.; Cardona, D. [Commissariat à l’Énergie Atomique, Centre de Valduc, F-21120 Is-sur-Tille (France)

    2015-04-21

    This work presents the development of an in-line energy dispersive L X-ray fluorescence spectrometer set-up, with a low power X-ray generator and a secondary target, for the determination of plutonium concentration in nitric acid solutions. The intensity of the L X-rays from the internal conversion and gamma rays emitted by the daughter nuclei from plutonium is minimized and corrected, in order to eliminate the interferences with the L X-ray fluorescence spectrum. The matrix effects are then corrected by the Compton peak method. A calibration plot for plutonium solutions within the range 0.1–20 g L{sup −1} is given.

  10. Quantum equations of motion for multimode laser generation with a spatial dependence of the atom interaction with the field taken into account

    Science.gov (United States)

    Kozlovskii, A. V.

    2011-04-01

    We derive equations of motion for the electromagnetic field operators a{q'/ + }aq″ for a three-level multimode laser with a spatial dependence of the interaction of atoms with the field of a standing wave in a cavity taken into account. We calculate and analyze the dynamics of means of photon numbers in the field modes and of the correlation function of field modes. We explore the effect of intermode correlations on the dynamics of establishing stationary laser generation. We find that taking the spatial dependence of the interaction of atoms with the field and the intermode correlation into account in investigating the means of photon numbers leads to revealing new properties of laser generation, such as saturation of the laser radiation intensity in a single-mode regime and generation of short light pulses of side below-threshold modes with the amplitudes depending on the initial state of the field in a cavity.

  11. Nonlinear spectral imaging of human hypertrophic scar based on two-photon excited fluorescence and second-harmonic generation.

    Science.gov (United States)

    Chen, G; Chen, J; Zhuo, S; Xiong, S; Zeng, H; Jiang, X; Chen, R; Xie, S

    2009-07-01

    A noninvasive method using microscopy and spectroscopy for analysing the morphology of collagen and elastin and their biochemical variations in skin tissue will enable better understanding of the pathophysiology of hypertrophic scars and facilitate improved clinical management and treatment of this disease. To obtain simultaneously microscopic images and spectra of collagen and elastin fibres in ex vivo skin tissues (normal skin and hypertrophic scar) using a nonlinear spectral imaging method, and to compare the morphological structure and spectral characteristics of collagen and elastin fibres in hypertrophic scar tissues with those of normal skin, to determine whether this approach has potential for in vivo assessment of the pathophysiology of human hypertrophic scars and for monitoring treatment responses as well as for tracking the process of development of hypertrophic scars in clinic. Ex vivo human skin specimens obtained from six patients aged from 10 to 50 years old who were undergoing skin plastic surgery were examined. Five patients had hypertrophic scar lesions and one patient had no scar lesion before we obtained his skin specimen. A total of 30 tissue section samples of 30 mum thickness were analysed by the use of a nonlinear spectral imaging system consisting of a femtosecond excitation light source, a high-throughput scanning inverted microscope, and a spectral imaging detection system. The high-contrast and high-resolution second harmonic generation (SHG) images of collagen and two-photon excited fluorescence (TPEF) images of elastin fibres in hypertrophic scar tissues and normal skin were acquired using the extracting channel tool of the system. The emission spectra were analysed using the image-guided spectral analysis method. The depth-dependent decay constant of the SHG signal and the image texture characteristics of hypertrophic scar tissue and normal skin were used to quantitatively assess the amount, distribution and orientation of their

  12. Determination of ultra trace arsenic species in water samples by hydride generation atomic absorption spectrometry after cloud point extraction

    Energy Technology Data Exchange (ETDEWEB)

    Ulusoy, Halil Ibrahim, E-mail: hiulusoy@yahoo.com [University of Cumhuriyet, Faculty of Science, Department of Chemistry, TR-58140, Sivas (Turkey); Akcay, Mehmet; Ulusoy, Songuel; Guerkan, Ramazan [University of Cumhuriyet, Faculty of Science, Department of Chemistry, TR-58140, Sivas (Turkey)

    2011-10-10

    Graphical abstract: The possible complex formation mechanism for ultra-trace As determination. Highlights: {yields} CPE/HGAAS system for arsenic determination and speciation in real samples has been applied first time until now. {yields} The proposed method has the lowest detection limit when compared with those of similar CPE studies present in literature. {yields} The linear range of the method is highly wide and suitable for its application to real samples. - Abstract: Cloud point extraction (CPE) methodology has successfully been employed for the preconcentration of ultra-trace arsenic species in aqueous samples prior to hydride generation atomic absorption spectrometry (HGAAS). As(III) has formed an ion-pairing complex with Pyronine B in presence of sodium dodecyl sulfate (SDS) at pH 10.0 and extracted into the non-ionic surfactant, polyethylene glycol tert-octylphenyl ether (Triton X-114). After phase separation, the surfactant-rich phase was diluted with 2 mL of 1 M HCl and 0.5 mL of 3.0% (w/v) Antifoam A. Under the optimized conditions, a preconcentration factor of 60 and a detection limit of 0.008 {mu}g L{sup -1} with a correlation coefficient of 0.9918 was obtained with a calibration curve in the range of 0.03-4.00 {mu}g L{sup -1}. The proposed preconcentration procedure was successfully applied to the determination of As(III) ions in certified standard water samples (TMDA-53.3 and NIST 1643e, a low level fortified standard for trace elements) and some real samples including natural drinking water and tap water samples.

  13. Quantifying uncertainty in the measurement of arsenic in suspended particulate matter by Atomic Absorption Spectrometry with hydride generator

    Directory of Open Access Journals (Sweden)

    Ahuja Tarushee

    2011-04-01

    Full Text Available Abstract Arsenic is the toxic element, which creates several problems in human being specially when inhaled through air. So the accurate and precise measurement of arsenic in suspended particulate matter (SPM is of prime importance as it gives information about the level of toxicity in the environment, and preventive measures could be taken in the effective areas. Quality assurance is equally important in the measurement of arsenic in SPM samples before making any decision. The quality and reliability of the data of such volatile elements depends upon the measurement of uncertainty of each step involved from sampling to analysis. The analytical results quantifying uncertainty gives a measure of the confidence level of the concerned laboratory. So the main objective of this study was to determine arsenic content in SPM samples with uncertainty budget and to find out various potential sources of uncertainty, which affects the results. Keeping these facts, we have selected seven diverse sites of Delhi (National Capital of India for quantification of arsenic content in SPM samples with uncertainty budget following sampling by HVS to analysis by Atomic Absorption Spectrometer-Hydride Generator (AAS-HG. In the measurement of arsenic in SPM samples so many steps are involved from sampling to final result and we have considered various potential sources of uncertainties. The calculation of uncertainty is based on ISO/IEC17025: 2005 document and EURACHEM guideline. It has been found that the final results mostly depend on the uncertainty in measurement mainly due to repeatability, final volume prepared for analysis, weighing balance and sampling by HVS. After the analysis of data of seven diverse sites of Delhi, it has been concluded that during the period from 31st Jan. 2008 to 7th Feb. 2008 the arsenic concentration varies from 1.44 ± 0.25 to 5.58 ± 0.55 ng/m3 with 95% confidence level (k = 2.

  14. Sample preparation for arsenic speciation analysis in baby food by generation of substituted arsines with atomic absorption spectrometry detection.

    Science.gov (United States)

    Huber, Charles S; Vale, Maria Goreti R; Dessuy, Morgana B; Svoboda, Milan; Musil, Stanislav; Dědina, Jiři

    2017-12-01

    A slurry sampling procedure for arsenic speciation analysis in baby food by arsane generation, cryogenic trapping and detection with atomic absorption spectrometry is presented. Several procedures were tested for slurry preparation, including different reagents (HNO3, HCl and tetramethylammonium hydroxide - TMAH) and their concentrations, water bath heating and ultrasound-assisted agitation. The best results for inorganic arsenic (iAs) and dimethylarsinate (DMA) were reached when using 3molL(-1) HCl under heating and ultrasound-assisted agitation. The developed method was applied for the analysis of five porridge powder and six baby meal samples. The trueness of the method was checked with a certified reference material (CRM) of total arsenic (tAs), iAs and DMA in rice (ERM-BC211). Arsenic recoveries (mass balance) for all samples and CRM were performed by the determination of the tAs by inductively coupled plasma mass spectrometry (ICP-MS) after microwave-assisted digestion and its comparison against the sum of the results from the speciation analysis. The relative limits of detection were 0.44, 0.24 and 0.16µgkg(-1) for iAs, methylarsonate and DMA, respectively. The concentrations of the most toxic arsenic species (iAs) in the analyzed baby food samples ranged between 4.2 and 99µgkg(-1) which were below the limits of 300, 200 and 100µgkg(-1) set by the Brazilian, Chinese and European legislation, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Simple decomposition procedure for determination of selenium in whole blood, serum and urine by hydride generation atomic absorption spectroscopy.

    Science.gov (United States)

    Tiran, B; Tiran, A; Rossipal, E; Lorenz, O

    1993-12-01

    A digestion procedure for selenium determination by hydride generation atomic absorption spectroscopy (AAS) in whole blood, serum and urine is described, it employs sulfuric acid, hydrogen peroxide and vanadium (V) sulfuric acid reagent solution. The method is rapid, uses no explosive reagents and can be performed at a constant temperature of 100 degrees C. Therefore, it is easily applicable in a routine clinical laboratory for a large amount of samples. The coefficient of intra-assay variation was 4.3-5.6%, the coefficient for inter-assay variation was 5-5.9% in the medium and high concentration range, and 5.8-8.6% in the low range. In analyzing several commercial reference materials our results showed good agreement with the target values. Analytical recovery by addition of sodium selenite and seleno-DL-methionine to samples ranged between 97 and 104%. The correlation between the described digestion procedure and the nitric, sulfuric and perchloric acid digestion procedure recommended by the International Union of Pure and Applied Chemistry showed good agreement for whole blood, serum and for urine. We determined selenium in serum (n = 58) and whole blood (n = 50) in a collective of healthy children from 1 to 5 years living in Styria, Austria. The low values in serum (35 +/- 11 micrograms/L) and whole blood (42 +/- 6 micrograms/L) at one year of life increased significantly to 48 +/- 13 mu/L (p = 0.033) and 55 +/- 6 micrograms/L (p = 0.004) at three years of life in serum and whole blood, respectively. The selenium concentration showed no further increase up to five years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

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

    Institute of Scientific and Technical Information of China (English)

    汪波; 辛跃珍

    2012-01-01

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

  17. Fluorescence behavior and singlet oxygen generating abilities of aluminum phthalocyanine in the presence of anisotropic gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mthethwa, Thandekile; Nyokong, Tebello, E-mail: t.nyokong@ru.ac.za

    2015-01-15

    Gold nanoparticles (spheres, rods and bipyramids) were synthesized. The nanocrystals were characterized by UV–visible spectrometry, transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The as prepared gold nanoparticles were then conjugated to a quaternized 2,(3)-tetra [2-(dimethylamino) ethanethio] substituted Al(OH) phthalocyanine (complex 1). The conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields and lifetimes. Conversely, an increase in the singlet oxygen quantum yields was observed for the conjugated complex 1 in the presence of AuNPs. - Highlights: • Gold nanoparticles (spheres, rods and bipyramids) were synthesized. • Gold nanoparticles were then conjugated to a quaternized ClAl phthalocyanine. • Conjugation of phthalocyanines with gold nanoparticles resulted in a decrease in the fluorescence quantum yields. • An increase in the singlet oxygen quantum yields was observed for the phthalocyanine in the presence of nanoparticles.

  18. A program of generation and selection of configurations for the configuration interaction method in atomic calculations SELECTCONF

    Science.gov (United States)

    Bogdanovich, P.; Karpuškienė, R.; Momkauskaitė, A.

    2005-11-01

    This program written in FORTRAN is aimed at generation and selection of the admixed configurations which are used in the theoretical calculations of atomic states by the configuration interaction (CI) method. The admixed configurations are generated and selected using the file of radial orbitals written down in the form adopted in the code [C. Froese Fischer, Comput. Phys. Comm. 43 (1987) 355] and other analogous codes. Selection of configurations is performed on the ground of evaluations in the second order of the perturbation theory [P. Bogdanovich, R. Karpu\\vskienė, Comput. Phys. Comm. 134 (2001) 321; R. Karpu\\vskienė, R. Karazija, P. Bogdanovich, Phys. Scripta 64 (2001) 333]. Output of selected configurations is arranged in a format suitable for the codes generating the configuration states [C. Froese Fischer, B. Liu, Comput. Phys. Comm. 64 (1991) 406; P. Bogdanovich, A. Momkauskaitė, Comput. Phys. Comm. 157 (2004) 217]. Program summaryTitle of program:SELECTCONF Catalogue identifier:ADWD Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADWD Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions:None Computers:Any computer with a FORTRAN 77 compiler Operating systems under which the program has been tested:Linux Programming language used:FORTRAN 77 Memory required to execute with typical data:4 MB No. of lines in distributed program, including test data, etc.:7459 No. of bytes in distributed program, including test data, etc.:108 420 Distribution format:gzip file Nature of the physical problem:Due to the restricted possibilities of the computers and codes, which are employed, the practice of CI requires one to select and superpose those configurations the usage of which happens to be the most effective. This program is designed for the selection of such admixed configurations. Method of solution:All admixed configurations possible in the specified basis set of radial orbitals (RO) are constructed

  19. Generations of dark hollow beams and their applications in laser cooling of atoms and all optical-type Bose-Einstein condensation

    Institute of Scientific and Technical Information of China (English)

    印建平; 高伟建; 王海峰; 龙全; 王育竹

    2002-01-01

    We report on a new experimental result to generate dark hollow beams by using a geometric optical method.We propose two new methods to produce focused and localized hollow laser beams by using π-phase plates. UsingMonte-Carlo simulations, we have studied the Sisyphus cooling of alkali atoms in pyramidal hollow beam gravito-opticaltraps. We discuss some potential applications of the dark hollow beams in atom optics and the preparation of an alloptically-cooled and optically-trapped atomic Bose-Einstein condensation (BEC).Our research shows that an ultracoldatomic sample with a temperature of ~ 2μK can be obtained in the pyramidal hollow beam dipole trap and an alloptical-type BEC may be realized in a far blue-detuned, hollow beam trap.

  20. Organic, inorganic and total mercury determination in fish by chemical vapor generation with collection on a gold gauze and electrothermal atomic absorption spectrometry

    Science.gov (United States)

    Duarte, Fábio Andrei; Bizzi, Cezar Augusto; Antes, Fabiane Goldschmidt; Dressler, Valderi Luiz; Flores, Érico Marlon de Moraes

    2009-06-01

    A method for organic, inorganic and total mercury determination in fish tissue has been developed using chemical vapor generation and collection of mercury vapor on a gold gauze inside a graphite tube and further atomization by electrothermal atomic absorption spectrometry. After drying and cryogenic grinding, potassium bromide and hydrochloric acid solution (1 mol L - 1 KBr in 6 mol L - 1 HCl) was added to the samples. After centrifugation, total mercury was determined in the supernatant. Organomercury compounds were selectively extracted from KBr solution using chloroform and the resultant solution was back extracted with 1% m/v L-cysteine. This solution was used for organic Hg determination. Inorganic Hg remaining in KBr solution was directly determined by chemical vapor generation electrothermal atomic absorption spectrometry. Mercury vapor generation from extracts was performed using 1 mol L - 1 HCl and 2.5% m/v NaBH 4 solutions and a batch chemical vapor generation system. Mercury vapor was collected on the gold gauze heated resistively at 80 °C and the atomization temperature was set at 650 °C. The selectivity of extraction was evaluated using liquid chromatography coupled to chemical vapor generation and determination by inductively coupled plasma mass spectrometry. The proposed method was applied for mercury analysis in shark, croaker and tuna fish tissues. Certified reference materials were used to check accuracy and the agreement was better than 95%. The characteristic mass was 60 pg and method limits of detection were 5, 1 and 1 ng g - 1 for organic, inorganic and total mercury, respectively. With the proposed method it was possible to analyze up to 2, 2 and 6 samples per hour for organic, inorganic and total Hg determination, respectively.

  1. Organic, inorganic and total mercury determination in fish by chemical vapor generation with collection on a gold gauze and electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, Fabio Andrei; Bizzi, Cezar Augusto; Goldschmidt Antes, Fabiane; Dressler, Valderi Luiz [Departamento de Quimica, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Flores, Erico Marlon de Moraes [Departamento de Quimica, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil)], E-mail: flores@quimica.ufsm.br

    2009-06-15

    A method for organic, inorganic and total mercury determination in fish tissue has been developed using chemical vapor generation and collection of mercury vapor on a gold gauze inside a graphite tube and further atomization by electrothermal atomic absorption spectrometry. After drying and cryogenic grinding, potassium bromide and hydrochloric acid solution (1 mol L{sup - 1} KBr in 6 mol L{sup - 1} HCl) was added to the samples. After centrifugation, total mercury was determined in the supernatant. Organomercury compounds were selectively extracted from KBr solution using chloroform and the resultant solution was back extracted with 1% m/v L-cysteine. This solution was used for organic Hg determination. Inorganic Hg remaining in KBr solution was directly determined by chemical vapor generation electrothermal atomic absorption spectrometry. Mercury vapor generation from extracts was performed using 1 mol L{sup - 1} HCl and 2.5% m/v NaBH{sub 4} solutions and a batch chemical vapor generation system. Mercury vapor was collected on the gold gauze heated resistively at 80 deg. C and the atomization temperature was set at 650 deg. C. The selectivity of extraction was evaluated using liquid chromatography coupled to chemical vapor generation and determination by inductively coupled plasma mass spectrometry. The proposed method was applied for mercury analysis in shark, croaker and tuna fish tissues. Certified reference materials were used to check accuracy and the agreement was better than 95%. The characteristic mass was 60 pg and method limits of detection were 5, 1 and 1 ng g{sup - 1} for organic, inorganic and total mercury, respectively. With the proposed method it was possible to analyze up to 2, 2 and 6 samples per hour for organic, inorganic and total Hg determination, respectively.

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

    Directory of Open Access Journals (Sweden)

    Hiroshi Yoshii

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

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

    Science.gov (United States)

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

    2014-01-01

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

  4. Two-photon spectral fluorescence lifetime and second-harmonic generation imaging of the porcine cornea with a 12-femtosecond laser microscope

    Science.gov (United States)

    Batista, Ana; Breunig, Hans Georg; Uchugonova, Aisada; Morgado, António Miguel; König, Karsten

    2016-03-01

    Five dimensional microscopy with a 12-fs laser scanning microscope based on spectrally resolved two-photon autofluorescence lifetime and second-harmonic generation (SHG) imaging was used to characterize all layers of the porcine cornea. This setup allowed the simultaneous excitation of both metabolic cofactors, NAD(P)H and flavins, and their discrimination based on their spectral emission properties and fluorescence decay characteristics. Furthermore, the architecture of the stromal collagen fibrils was assessed by SHG imaging in both forward and backward directions. Information on the metabolic state and the tissue architecture of the porcine cornea were obtained with subcellular resolution, and high temporal and spectral resolutions.

  5. Generation of One-Dimensional Array of Focused Hollow-Beam Pipes and Its Surface Microscopic Waveguide for Cold Atoms or Molecules

    Institute of Scientific and Technical Information of China (English)

    JI Xian-Ming; XIA Yong; YIN Jian-Ping

    2004-01-01

    We propose a new scheme to guide cold atoms (or molecules) by using a one-dimensional (1D) array of focused hollow-beam pipes generated by the combination of a binary phase grating and a 1D array of micro-cylindrical lenses on the substrate surface. We also calculate the intensity distribution of the focused hollow-beam pipe array and its optical potential for 85Rb atoms. The result shows that when the blue detuning of the incident beam and its intensity are 10 GHz and 7.0 × 103 W/m2 respectively, the horizontal dark spot size of each focused hollow-beam pipe and the efficient optical potential are 4.4μm and ~ 0.23mK, which is high enough to guide cold 85Rb atoms (~ 20 μK) from a standard optical molasses and then to realize the 1D array of surface atomic waveguides on an atom chip.

  6. Fluorescence-Based Sensors

    Science.gov (United States)

    Orellana, Guillermo

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

  7. Determination of Mecruy at Trace Level in Natural Water Samples by Hydride Generation Atomic Absorption Spectrophotometry after Cloud Point Extraction Preconcentration

    Institute of Scientific and Technical Information of China (English)

    Ji Ying SONG; Ming HOU; Li Xiang ZHANG

    2006-01-01

    A method for the determination of trace mercury in water samples by hydride generation atomic absorption spectrophotometry after cloud point extraction was proposed in the present work.The effects of pH, concentration of surfactant, and equilibration time on cloud point extraction were discussed. The enhancement factor of 20 and the detection limit of 0.039 μg/L were obtained for mercury with relative standard deviation of 4.8% (n = 11).

  8. On-line monitoring of particulate iron oxides in steam generator feedwater using x-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Stauffer, C.C.; Connolly, D.J. [Babcock and Wilcox, Alliance, OH (United States). Research and Development Division; Millett, P.J. [Electric Power Research Inst., Palo Alto, CA (United States)

    1995-12-01

    Corrosion product monitoring is important as power plants strive to minimize corrosion and maximize availability. Current methodology for monitoring corrosion products involves grab sampling and/or collection of integrated samples using membrane filters followed by analysis of the membranes in the laboratory. This technique is labor intensive and provides only average values over lengthy sampling intervals (typically 1--3 days). Recently, a laboratory tool -- x-ray fluorescence (XRF) spectroscopy -- was combined with existing on-line sampling techniques resulting in an on-line XRF monitor capable of measuring iron oxide particulates in a flowing stream at the parts-per-billion (ppb) level and below. After development in the laboratory, the instrument was successfully field tested in two power plants. After testing at the first power plant, modifications to improve instrument performance were incorporated. This paper presents information regarding design and operation of the instrument, improvements made during the first test period, and field data obtained during plant service. Results show that this instrument will provide on-line measurements of iron oxides at the ppb level with minimal operator involvement. Finally, there are wider applications for this on-line XRF monitor. Though the present system is geared toward iron analysis in corrosion products, it could as well be configured for other elements or groups of elements for other applications such lead, sulfur, copper, chromium, or any other element detectable by x-ray fluorescence.

  9. Consequences experimentales des effets des fluctuations du vide sur la fluorescence parametrique et la generation du second harmonique en milieu confine

    Science.gov (United States)

    Robichaud, Luc

    Les fluctuations du vide, qui consistent en l'apparition momentanee de particules, ce qui est permit par le principe d'incertitude de Heisenberg, joue un role primordial dans les processus photoniques, en particulier les processus non-lineaires. Par la manipulation de ces fluctuations du vide a l'aide de confinement optique, on retrouve deux phenomenes particuliers : l'intensification de la fluorescence parametrique (Walker, 2008) et l'inhibition de la generation du second harmonique (Collette, 2013). Dans ce travail, on presente les resultats dans le cas classique ; c'est-a-dire sans fluctuations du vide et confinement. Par la suite, on presente les effets des fluctuations du vide et du confinement, ce qui mene aux deux effets mentionnes. Dans le cas de la fluorescence parametrique, le bruit quantique sur le champ interne et externe est calcule, le role du desaccord de phase dans le modele est expose et une generalisation tridimensionnelle est etudiee afin de generaliser la conception du modele d'un cas unidimensionnel a un cas tridimensionnel planaire. Dans le cas de la generation du second harmonique, les difficultes d'un modele purement tridimensionnel sont exposees et ensuite le cas limite planaire est etudie.

  10. 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

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

    NARCIS (Netherlands)

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

    1972-01-01

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

  12. Cloud condensation nucleus (CCN behavior of organic aerosol particles generated by atomization of water and methanol solutions

    Directory of Open Access Journals (Sweden)

    T. A. Rissman

    2007-06-01

    Full Text Available Cloud condensation nucleus (CCN experiments were carried out for malonic acid, succinic acid, oxalacetic acid, DL-malic acid, glutaric acid, DL-glutamic acid monohydrate, and adipic acid, using both water and methanol as atomization solvents, at three operating supersaturations (0.11%, 0.21%, and 0.32% in the Caltech three-column CCN instrument (CCNC3. Predictions of CCN behavior for five of these compounds were made using the Aerosol Diameter Dependent Equilibrium Model (ADDEM. The experiments presented here expose important considerations associated with the laboratory measurement of the CCN behavior of organic compounds. Choice of atomization solvent results in significant differences in CCN activation for some of the compounds studied, which could result from residual solvent, particle morphology differences, and chemical reactions between the particle and gas phases. Also, significant changes in aerosol size distribution occurred after classification in a differential mobility analyzer (DMA for malonic acid and glutaric acid, preventing confident interpretation of experimental data for these two compounds. Filter analysis of adipic acid atomized from methanol solution indicates that gas-particle phase reactions may have taken place after atomization and before methanol was removed from the sample gas stream. Careful consideration of these experimental issues is necessary for successful design and interpretation of laboratory CCN measurements.

  13. Cloud condensation nucleus (CCN behavior of organic aerosol particles generated by atomization of water and methanol solutions

    Directory of Open Access Journals (Sweden)

    T. A. Rissman

    2006-12-01

    Full Text Available Cloud condensation nucleus (CCN experiments were carried out for malonic acid, succinic acid, oxalacetic acid, DL-malic acid, glutaric acid, DL-glutamic acid monohydrate, and adipic acid, using both water and methanol as atomization solvents, at three operating supersaturations (0.11% 0.21%, and 0.32% in the Caltech three-column CCN instrument (CCNC3. Predictions of CCN behavior for five of these compounds were made using the Aerosol Diameter Dependent Equilibrium Model (ADDEM. The experiments presented here expose important considerations associated with the laboratory measurement of the CCN behavior of organic compounds. Choice of atomization solvent results in significant differences in CCN activation for some of the compounds studied, which could result from residual solvent, particle morphology differences, and chemical reactions between the particle and gas phases. Also, significant changes in aerosol size distribution occurred after classification in a differential mobility analyzer (DMA for malonic acid and glutaric acid. Filter analysis of adipic acid atomized from methanol solution indicates that gas-particle phase reactions may have taken place after atomization and before the methanol was removed from the sample gas stream. Careful consideration of these experimental issues is necessary for successful design and interpretation of laboratory CCN measurements.

  14. Cloud condensation nucleus (CCN) behavior of organic aerosol particles generated by atomization of water and methanol solutions

    Science.gov (United States)

    Rissman, T. A.; Varutbangkul, V.; Surratt, J. D.; Topping, D. O.; McFiggans, G.; Flagan, R. C.; Seinfeld, J. H.

    2007-06-01

    Cloud condensation nucleus (CCN) experiments were carried out for malonic acid, succinic acid, oxalacetic acid, DL-malic acid, glutaric acid, DL-glutamic acid monohydrate, and adipic acid, using both water and methanol as atomization solvents, at three operating supersaturations (0.11%, 0.21%, and 0.32%) in the Caltech three-column CCN instrument (CCNC3). Predictions of CCN behavior for five of these compounds were made using the Aerosol Diameter Dependent Equilibrium Model (ADDEM). The experiments presented here expose important considerations associated with the laboratory measurement of the CCN behavior of organic compounds. Choice of atomization solvent results in significant differences in CCN activation for some of the compounds studied, which could result from residual solvent, particle morphology differences, and chemical reactions between the particle and gas phases. Also, significant changes in aerosol size distribution occurred after classification in a differential mobility analyzer (DMA) for malonic acid and glutaric acid, preventing confident interpretation of experimental data for these two compounds. Filter analysis of adipic acid atomized from methanol solution indicates that gas-particle phase reactions may have taken place after atomization and before methanol was removed from the sample gas stream. Careful consideration of these experimental issues is necessary for successful design and interpretation of laboratory CCN measurements.

  15. The influence of spontaneously generated coherence on atom-photon entanglement in a Λ-type system with an incoherent pump

    Science.gov (United States)

    Yang, Xin; Yan, Dong; Bao, Qianqian; Zhang, Yan; Cui, Cuili

    2014-12-01

    Owing to interference induced by spontaneous emission, the density-matrix equations in a three-level Λ-type system have an additional coherence term, which plays a critical role in modulating the inversionless gain and electromagnetically induced transparency effect. In addition, it is shown that spontaneously generated coherence (SGC) has an effect on the entanglement between an atom and a photon of the coupling laser field by calculating the degree of entanglement (DEM) of the atomic system. In this paper, we investigate the influence of the SGC effect on atom-photon entanglement in a Λ-type system, which generally remains a high entangled state. When an incoherent pump source is introduced, we find that the SGC effect could exert considerable influence on the atom reduced entropy under certain conditions for both transient and steady states. More interestingly, such an incoherent pump field could actively affect the short-time dynamic behaviors of the transient quantum entangled state at a certain range of pump rate as a typical coherent case.

  16. Accurate Atom Counting in Mesoscopic Ensembles

    CERN Document Server

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

    2013-01-01

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

  17. Accurate Atom Counting in Mesoscopic Ensembles

    Science.gov (United States)

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

    2013-12-01

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

  18. Accurate atom counting in mesoscopic ensembles.

    Science.gov (United States)

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

    2013-12-20

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

  19. Comparative fluorescence two-dimensional gel electrophoresis using a gel strip sandwich assembly for the simultaneous on-gel generation of a reference protein spot grid.

    Science.gov (United States)

    Ackermann, Doreen; Wang, Weiqun; Streipert, Benjamin; Geib, Birgit; Grün, Lothar; König, Simone

    2012-05-01

    The comparison of proteins separated on 2DE is difficult due to gel-to-gel variability. Here, a method named comparative fluorescence gel electrophoresis (CoFGE) is presented, which allows the generation of an artificial protein grid in parallel to the separation of an analytical sample on the same gel. Different fluorescent stains are used to distinguish sample and marker on the gel. The technology combines elements of 1DE and 2DE. Special gel combs with V-shaped wells are placed in a stacking gel above the pI strip. Proteins separated on the pI strip are electrophoresed at the same time as marker proteins (commercially available purified protein of different molecular weight) placed in V-wells. In that way, grids providing approximately 100 nodes as landmarks for the determination of protein spot coordinates are generated. Data analysis is possible with commercial 2DE software capable of warping. The method improves comparability of 2DE protein gels, because they are generated in combination with regular in-gel anchor points formed by protein standards. This was shown here for two comparative experiments with three gels each using Escherichia coli lysate. For a set of 47 well-defined samples spots, the deviation of the coordinates was improved from 7% to less than 1% applying warping using the marker grid. Conclusively, as long as the same protein markers, the same size of pI-strips and the same technology are used, gel matching is reproducibly possible. This is an important advancement for projects involving comparison of 2DE-gels produced over several years and in different laboratories. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Förster Resonance Energy Transfer Switchable Self-Assembled Micellar Nanoprobe: Ratiometric Fluorescent Trapping of Endogenous H2S Generation via Fluvastatin-Stimulated Upregulation.

    Science.gov (United States)

    Zhao, Chunchang; Zhang, Xiuli; Li, Kaibin; Zhu, Shaojia; Guo, Zhiqian; Zhang, Lili; Wang, Feiyi; Fei, Qiang; Luo, Sihang; Shi, Ping; Tian, He; Zhu, Wei-Hong

    2015-07-08

    H2S produced in small amounts by mammalian cells has been identified in mediating biological signaling functions. However, the in situ trapping of endogenous H2S generation is still handicapped by a lack of straightforward methods with high selectivity and fast response. Here, we encapsulate a semi-cyanine-BODIPY hybrid dye (BODInD-Cl) and its complementary energy donor (BODIPY1) into the hydrophobic interior of an amphiphilic copolymer (mPEG-DSPE), especially for building up a ratiometric fluorescent H2S nanoprobe with extraordinarily fast response. A remarkable red-shift in the absorption band with a gap of 200 nm in the H2S response can efficiently switch off the Förster resonance energy transfer (FRET) from BODIPY1 to BODInD-Cl, subsequently recovering the donor fluorescence. Impressively, both the interior hydrophobicity of supramolecular micelles and electron-withdrawing nature of indolium unit in BODInD-Cl can sharply increase aromatic nucleophilic substitution with H2S. The ratiometric strategy based on the unique self-assembled micellar aggregate NanoBODIPY achieves an extremely fast response, enabling in situ imaging of endogenous H2S production and mapping its physiological and pathological consequences. Moreover, the amphiphilic copolymer renders the micellar assembly biocompatible and soluble in aqueous solution. The established FRET-switchable macromolecular envelope around BODInD-Cl and BODIPY1 enables cellular uptake, and makes a breakthrough in the trapping of endogenous H2S generation within raw264.7 macrophages upon stimulation with fluvastatin. This study manifests that cystathione γ-lyase (CSE) upregulation contributes to endogenous H2S generation in fluvastatin-stimulated macrophages, along with a correlation between CSE/H2S and activating Akt signaling pathway.

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

    CERN Document Server

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

    2010-01-01

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

  2. New Dioxaborolane Chemistry Enables [(18)F]-Positron-Emitting, Fluorescent [(18)F]-Multimodality Biomolecule Generation from the Solid Phase.

    Science.gov (United States)

    Rodriguez, Erik A; Wang, Ye; Crisp, Jessica L; Vera, David R; Tsien, Roger Y; Ting, Richard

    2016-05-18

    New protecting group chemistry is used to greatly simplify imaging probe production. Temperature and organic solvent-sensitive biomolecules are covalently attached to a biotin-bearing dioxaborolane, which facilitates antibody immobilization on a streptavidin-agarose solid-phase support. Treatment with aqueous fluoride triggers fluoride-labeled antibody release from the solid phase, separated from unlabeled antibody, and creates [(18)F]-trifluoroborate-antibody for positron emission tomography and near-infrared fluorescent (PET/NIRF) multimodality imaging. This dioxaborolane-fluoride reaction is bioorthogonal, does not inhibit antigen binding, and increases [(18)F]-specific activity relative to solution-based radiosyntheses. Two applications are investigated: an anti-epithelial cell adhesion molecule (EpCAM) monoclonal antibody (mAb) that labels prostate tumors and Cetuximab, an anti-epidermal growth factor receptor (EGFR) mAb (FDA approved) that labels lung adenocarcinoma tumors. Colocalized, tumor-specific NIRF and PET imaging confirm utility of the new technology. The described chemistry should allow labeling of many commercial systems, diabodies, nanoparticles, and small molecules for dual modality imaging of many diseases.

  3. Simulation of the Ising model, memory for Bell states and generation of four-atom entangled states in cavity QED

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A scheme is proposed to simulate the Ising model and preserve the maximum entangled states (Bell states) in cavity quantum electrodynamics (QED) driven by a classical field with large detuning. In the strong driving and large-detuning regime, the effective Hamiltonian of the system is the same as the standard Ising model, and the scheme can also make the initial four Bell states of two atoms at the maximum entanglement all the time. So it is a simple memory for the maximal entangled states. The system is insensitive to the cavity decay and the thermal field and more immune to decoherence. These advantages can warrant the experimental feasibility of the current scheme. Furthermore, the genuine four-atom entanglement may be acquired via two Bell states through one-step implementation on four two-level atoms in the strong-driven model, and when two Greenberger-Horne-Zeilinger (GHZ) states are prepared in our scheme, the entangled cluster state may be acquired easily. The success probability for the scheme is 1.

  4. Isolation of yellow catfish β-actin promoter and generation of transgenic yellow catfish expressing enhanced yellow fluorescent protein.

    Science.gov (United States)

    Ge, Jiachun; Dong, Zhangji; Li, Jingyun; Xu, Zhiqiang; Song, Wei; Bao, Jie; Liang, Dong; Li, Junbo; Li, Kui; Jia, Wenshuang; Zhao, Muzi; Cai, Yongxiang; Yang, Jiaxin; Pan, Jianlin; Zhao, Qingshun

    2012-10-01

    Yellow catfish (Pelteobagrus fulvidraco Richardson) is one of the most important freshwater farmed species in China. However, its small size and slow growth rate limit its commercial value. Because genetic engineering has been a powerful tool to develop and improve fish traits for aquaculture, we performed transgenic research on yellow catfish in order to increase its size and growth rate. Performing PCR with degenerate primers, we cloned a genomic fragment comprising 5'-flanking sequence upstream of the initiation codon of β-actin gene in yellow catfish. The sequence is 1,017 bp long, containing the core sequence of proximal promoter including CAAT box, CArG motif and TATA box. Microinjecting the transgene construct Tg(beta-actin:eYFP) of the proximal promoter fused to enhanced yellow fluorescent protein (eYFP) reporter gene into zebrafish and yellow catfish embryos, we found the promoter could drive the reporter to express transiently in both embryos at early development. Screening the offspring of five transgenic zebrafish founders developed from the embryos microinjected with Tg(ycbeta-actin:mCherry) or 19 yellow catfish founders developed from the embryos microinjected with Tg(beta-actin:eYFP), we obtained three lines of transgenic zebrafish and one transgenic yellow catfish, respectively. Analyzing the expression patterns of the reporter genes in transgenic zebrafish (Tg(ycbeta-actin:mCherry)nju8/+) and transgenic yellow catfish (Tg(beta-actin:eYFP)nju11/+), we found the reporters were broadly expressed in both animals. In summary, we have established a platform to make transgenic yellow catfish using the proximal promoter of its own β-actin gene. The results will help us to create transgenic yellow catfish using "all yellow catfish" transgene constructs.

  5. Nonlinear spectral imaging of human normal skin, basal cell carcinoma and squamous cell carcinoma based on two-photon excited fluorescence and second-harmonic generation

    Science.gov (United States)

    Xiong, S. Y.; Yang, J. G.; Zhuang, J.

    2011-10-01

    In this work, we use nonlinear spectral imaging based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) for analyzing the morphology of collagen and elastin and their biochemical variations in basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and normal skin tissue. It was found in this work that there existed apparent differences among BCC, SCC and normal skin in terms of their thickness of the keratin and epithelial layers, their size of elastic fibers, as well as their distribution and spectral characteristics of collagen. These differences can potentially be used to distinguish BCC and SCC from normal skin, and to discriminate between BCC and SCC, as well as to evaluate treatment responses.

  6. One-step generation of triple knockout CHO cell lines using CRISPR/Cas9 and fluorescent enrichment

    DEFF Research Database (Denmark)

    Grav, Lise Marie; Lee, Jae Seong; Thomsen, Signe Gerling

    2015-01-01

    The CRISPR/Cas9 genome editing technology has previously been shown to be a highly efficient tool for generating gene disruptions in CHO cells. In this study we further demonstrate the applicability and efficiency of CRISPR/Cas9 genome editing by disrupting FUT8, BAK and BAX simultaneously....... Taken together, multiplexing with CRISPR/Cas9 can accelerate genome engineering efforts in CHO cells even further....

  7. Generation of a Natural Glycan Microarray Using 9-Fluorenylmethyl Chloroformate (FmocCl) as a Cleavable Fluorescent Tag

    OpenAIRE

    Song, Xuezheng; Lasanajak, Yi; Rivera-Marrero, Carlos; Luyai, Anthony; Willard, Margaret; Smith, David F.; Cummings, Richard D.

    2009-01-01

    Glycan microarray technology has become a successful tool for studying protein-carbohydrate interactions, but a limitation has been the laborious synthesis of glycan structures by enzymatic and chemical methods. Here we describe a new method to generate quantifiable glycan libraries from natural sources by combining widely used protease digestion of glycoproteins and Fmoc chemistry. Glycoproteins including chicken ovalbumin, bovine fetuin, and horseradish peroxidase (HRP) were digested by pro...

  8. 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)

  9. LEDs for fluorescence microscopy

    NARCIS (Netherlands)

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

    2004-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    贾书朝; 冯美云

    2014-01-01

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

  11. Generation of few-cycle laser pulses:Comparison between atomic and molecular gases in a hollow-core fiber

    Institute of Scientific and Technical Information of China (English)

    黄志远; 戴晔; 赵睿睿; 王丁; 冷雨欣

    2016-01-01

    We numerically study the pulse compression approaches based on atomic or molecular gases in a hollow-core fiber. From the perspective of self-phase modulation (SPM), we give the extensive study of the SPM infl uence on a probe pulse with molecular phase modulation (MPM) effect. By comparing the two compression methods, we summarize their advan-tages and drawbacks to obtain the few-cycle pulses with micro-or millijoule energies. It is also shown that the double pump-probe approach can be used as a tunable dual-color source by adjusting the time delay between pump and probe pulses to proper values.

  12. Absorption, fluorescence and second harmonic generation in Cr3+-doped BiB3O6 glasses

    Science.gov (United States)

    Kuznik, W.; Fuks-Janczarek, I.; Wojciechowski, A.; Kityk, I. V.; Kiisk, V.; Majchrowski, A.; Jaroszewicz, L. R.; Brik, M. G.; Nagy, G. U. L.

    2015-06-01

    Synthesis, spectral properties and photoinduced nonlinear optical effects of chromium-doped BiB3O6 glass are studied in the present paper. Absorption, excitation and time resolved luminescence spectra are presented and luminescence decay behavior is discussed. Detailed analysis of the obtained spectra (assignment of the most prominent spectral features in terms of the corresponding Cr3+ energy levels, crystal field strength Dq, Racah parameters B and C) was performed. A weak photostimulated second harmonic generation signal was found to increase drastically due to poling by proton implantation in the investigated sample.

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

    Institute of Scientific and Technical Information of China (English)

    辛禄德; 李强; 王建玲; 劳斐; 田树革

    2014-01-01

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

  14. Coherent generation and dynamic manipulation of double stationary light pulses in a five-level double-tripod system of cold atoms

    Energy Technology Data Exchange (ETDEWEB)

    Bao Qianqian; Zhang Xiaohang; Gao Junyan; Zhang Yan; Cui Cuili; Wu Jinhui [College of Physics, Jilin University, Changchun 130012 (China)

    2011-12-15

    We study a five-level double-tripod system of cold atoms for efficiently manipulating the dynamic propagation and evolution of a quantum probe field by modulating four classical control fields. Our numerical results show that it is viable to transform the quantum probe field into a pair of two-color stationary light pulses mutually coupled through two wave packets of atomic spin coherence. The pair of stationary light pulses can be released either from the sample entrance and exit synchronously or just from the sample exit with a controlled time delay. In addition, the two-color stationary light pulses are immune to the fast decay originating from the higher-order Fourier components of atomic spin and optical coherence, and may exhibit the quantum limited beating signals with their characteristic frequency determined by detunings of the four classical control fields. These results could be explored to design novel photonic devices, such as optical routing, beam splitter, and beat generator, for manipulating a quantum light field.

  15. Color atomic force microscopy: A method to acquire three independent potential parameters to generate a color image

    Science.gov (United States)

    Allain, P. E.; Damiron, D.; Miyazaki, Y.; Kaminishi, K.; Pop, F. V.; Kobayashi, D.; Sasaki, N.; Kawakatsu, H.

    2017-09-01

    Atomic force microscopy has enabled imaging at the sub-molecular level, and 3D mapping of the tip-surface potential field. However, fast identification of the surface still remains a challenging topic for the microscope to enjoy widespread use as a tool with chemical contrast. In this paper, as a step towards implementation of such function, we introduce a control scheme and mathematical treatment of the acquired data that enable retrieval of essential information characterizing this potential field, leading to fast acquisition of images with chemical contrast. The control scheme is based on the tip sample distance modulation at an angular frequency ω, and null-control of the ω component of the measured self-excitation frequency of the oscillator. It is demonstrated that this control is robust, and that effective Morse Parameters that give satisfactory curve fit to the measured frequency shift can be calculated at rates comparable to the scan. Atomic features with similar topography were distinguished by differences in these parameters. The decay length parameter was resolved with a resolution of 10 pm. The method was demonstrated on quenched silicon at a scan rate comparable to conventional imaging.

  16. A novel analytical system involving hydride generation and gold-coated W-coil trapping atomic absorption spectrometry for selenium determination at ng l{sup -1} level

    Energy Technology Data Exchange (ETDEWEB)

    Kula, I. [Department of Chemistry, Mugla University, 48000 Mugla (Turkey); Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Arslan, Y. [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Department of Chemistry, Atatuerk University, 25240 Erzurum (Turkey); Bakirdere, S. [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Department of Chemistry, Zonguldak Karaelmas University, 67100 Zonguldak (Turkey); Ataman, O.Y. [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey)], E-mail: ataman@metu.edu.tr

    2008-08-15

    A novel analytical technique was developed where gaseous hydrogen selenide formed by sodium tetrahydroborate reduction is transported to and trapped on a resistively heated gold-coated W-coil atom trap for in situ preconcentration. Gold coating on W-coil was prepared by using an organic solution of Au. The atom trap is held at 165 {sup o}C during the collection stage and is heated up to 675 deg. C for revolatilization; analyte species formed are transported to an externally heated quartz T-tube where the atomization takes place and the transient signal is obtained. The carrier gas consisted of 112.5 ml min{sup -1} Ar with 75 ml min{sup -1} H{sub 2} during the collection step and 112.5 ml min{sup -1} Ar with 450 ml min{sup -1} H{sub 2} in the revolatilization step. The half width of the transient signal obtained is less than 0.5 s. The RSD for the measurements was found to be 3.9% (n = 11) for 0.10 {mu}g l{sup -1} Se using peak height measurements. The calibration plot for 27.0 ml of sample collected in 4.0 min using a flow rate of 6.75 ml min{sup -1} was linear between 0.13 and 2.0 {mu}g l{sup -1} of Se. The limit of detection (3 s) is 39 ng l{sup -1}. The enhancement factor for the characteristic concentration (C{sub o}) was found to be 20.1 when compared to conventional hydride generation atomic absorption spectrometry system without trap. In order to check the accuracy of the method, standard reference material, natural water NIST 1640 was employed; the result was found to be in good agreement with the certified value at the 95% confidence level.

  17. A novel analytical system involving hydride generation and gold-coated W-coil trapping atomic absorption spectrometry for selenium determination at ng l - 1 level

    Science.gov (United States)

    Kula, İ.; Arslan, Y.; Bakırdere, S.; Ataman, O. Y.

    2008-08-01

    A novel analytical technique was developed where gaseous hydrogen selenide formed by sodium tetrahydroborate reduction is transported to and trapped on a resistively heated gold-coated W-coil atom trap for in situ preconcentration. Gold coating on W-coil was prepared by using an organic solution of Au. The atom trap is held at 165 °C during the collection stage and is heated up to 675 °C for revolatilization; analyte species formed are transported to an externally heated quartz T-tube where the atomization takes place and the transient signal is obtained. The carrier gas consisted of 112.5 ml min - 1 Ar with 75 ml min - 1 H 2 during the collection step and 112.5 ml min - 1 Ar with 450 ml min - 1 H 2 in the revolatilization step. The half width of the transient signal obtained is less than 0.5 s. The RSD for the measurements was found to be 3.9% ( n = 11) for 0.10 µg l - 1 Se using peak height measurements. The calibration plot for 27.0 ml of sample collected in 4.0 min using a flow rate of 6.75 ml min - 1 was linear between 0.13 and 2.0 µg l - 1 of Se. The limit of detection (3 s) is 39 ng l - 1 . The enhancement factor for the characteristic concentration ( Co) was found to be 20.1 when compared to conventional hydride generation atomic absorption spectrometry system without trap. In order to check the accuracy of the method, standard reference material, natural water NIST 1640 was employed; the result was found to be in good agreement with the certified value at the 95% confidence level.

  18. Comparative investigation of third and fifth harmonic generation in atomic and molecular gases driven by mid-infrared ultrafast laser pulses

    CERN Document Server

    Ni, Jielei; Zeng, Bin; Chu, Wei; Li, Guihua; Zhang, Haisu; Jing, Chenrui; Chin, See Leang; Cheng, Ya; Xu, Zhizhan

    2011-01-01

    We report on the comparative experimental investigation on third and fifth harmonic generation (THG and FHG) in atomic and molecular gases driven by mid-infrared ultrafast laser pulses at a wavelength of ~1500 nm. We observe that the conversion efficiencies of both the THG and FHG processes saturate at similar peak intensities close to ~1.5\\times1014 W/cm2 for argon, nitrogen, and air, whose ionization potentials are close to each other. Near the saturation intensity, the ratio of yields of the FHG and THG reaches ~10-1 for all the gases. Our results show that high-order Kerr effects do exist, whereas they are insufficient to balance the Kerr self-focusing without the assistance of plasma generation.

  19. 911 Call Center (PSAP) Service Areas, Master coverage of "atom" features used as a source to generate several derivative layers for the Sheriff RMS and E-911 map rolls. Cover is painstakingly maintained interactively by GIS staff. All atom boundaries are snapped to the road centerline cover, Published in 2008, 1:1200 (1in=100ft) scale, Sedgwick County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — 911 Call Center (PSAP) Service Areas dataset current as of 2008. Master coverage of "atom" features used as a source to generate several derivative layers for the...

  20. Generation of few-cycle laser pulses: Comparison between atomic and molecular gases in a hollow-core fiber

    Science.gov (United States)

    Zhi-Yuan, Huang; Ye, Dai; Rui-Rui, Zhao; Ding, Wang; Yu-Xin, Leng

    2016-07-01

    We numerically study the pulse compression approaches based on atomic or molecular gases in a hollow-core fiber. From the perspective of self-phase modulation (SPM), we give the extensive study of the SPM influence on a probe pulse with molecular phase modulation (MPM) effect. By comparing the two compression methods, we summarize their advantages and drawbacks to obtain the few-cycle pulses with micro- or millijoule energies. It is also shown that the double pump-probe approach can be used as a tunable dual-color source by adjusting the time delay between pump and probe pulses to proper values. Project supported by the National Natural Science Foundation of China (Grant Nos. 11204328, 61221064, 61078037, 11127901, 11134010, and 61205208), the National Basic Research Program of China (Grant No. 2011CB808101), and the Natural Science Foundation of Shanghai, China (Grant No. 13ZR1414800).

  1. Memristive Behavior in Electrohydrodynamic Atomized Layers of Poly[2-methoxy-5-(2'-ethylhexyloxy)-(p-phenylenevinylene)] for Next Generation Printed Electronics

    Science.gov (United States)

    Naeem Awais, Muhammad; Choi, Kyung Hyun

    2013-05-01

    Poly[2-methoxy-5-(2'-ethylhexyloxy)-(p-phenylenevinylene)] (MEH:PPV) based organic memristor (memory resistor) has been fabricated on the indium-tin oxide (ITO) coated poly(ethylene terepthalate) (PET) substrate by the electrohydrodynamic atomization (EHDA) technique. Thin jet containing MEH:PPV polymer was generated through a capillary under electrical stresses. The jet was broken into small droplets by adjusting the distance from nozzle to substrate and collected over the substrate under normal room conditions, consequently a high quality layer of MEH:PPV was achieved with an average thickness of 168 nm. The layer was morphologically characterized by a field emission scanning electron microscope (FESEM) analysis. X-ray photoelectron spectroscope (XPS) analysis was also carried out to confirm the chemistry of the deposited material. Electrically, ITO/MEH:PPV/Ag fabricated memristor was found to be switchable between high state and low state between +/-4 V. The research work provides the memristive behavior in electrohydrodynamic atomized layers of MEH:PPV to be used for the next generation printed electronics application.

  2. Design of a method for generation of gas-phase hydroxyl radicals, and use of HPLC with fluorescence detection to assess the antioxidant capacity of natural essential oils.

    Science.gov (United States)

    Pezo, D; Salafranca, J; Nerín, C

    2006-08-01

    The use of natural antioxidants is of increasing importance in the human diet, because they are recognised as compounds essential to health which minimize or delay the aging process. Despite apparent simplicity, however, it is very difficult to measure and quantify such properties, for which a robust analytical method is required. Because oxidation usually is caused by the presence of OH* radicals, a new method involving the in-situ, vapour-phase generation of these radicals and their quantification in the presence and absence of potential antioxidant extracts has been developed. The oxidant atmosphere generated from hydrogen peroxide is carried by an air stream through an empty quartz chamber in which UV radiation promotes the formation of radicals by a photochemical reaction. The products then pass through a cartridge containing the essential oil, finally bubbling into an impinger containing an aqueous solution of salicylic acid, at pH 4.5, which reacts with the OH* radicals forming 2,5-dihydroxybenzoic acid. This solution is quantified by RP-HPLC using UV and fluorescence detectors connected in series. Detection and quantification limits for OH* radicals were approximately 0.01 pg g(-1) air. Description and optimization of the method are discussed, as also is the antioxidant performance of an extract of ginger (Zingiber officinale R.), which reduced the oxidation process by up to 92%.

  3. Generation and characterization of a recombinant Newcastle disease virus expressing the red fluorescent protein for use in co-infection studies

    Directory of Open Access Journals (Sweden)

    Li Jinnan

    2012-10-01

    Full Text Available Abstract Background Many viruses have evolved multiple strategies to prevent super infection of host cells by more than one virion. This phenomenon, known as super infection exclusion, may play an important role on virus evolution because it can affect the frequency of reassortment and/or recombination. Newcastle disease virus (NDV, a negative sense single-stranded RNA virus, is characterized by its continuous evolutionary dynamics and by a low frequency of recombination events. However, the mechanisms that contribute to the low recombination rates on NDV are still not completely understood. Methods In this study we assessed the ability of two NDV strains (LaSota and B1 to super infect host cells in vitro. We generated a recombinant NDV strain LaSota expressing the red fluorescent protein (RFP and used it in co-infection assays with a related NDV strain B1 expressing the green fluorescent protein (GFP. DF-1 cells were inoculated with both viruses at the same time or at different intervals between primary infection and super infection. Results When both viruses were inoculated at the same time point, a 27% co-infection rate was observed, whereas when they were inoculated at different time points the super infection rates decreased to levels as low as 1.4%. Conclusions These results indicate that although different NDV strains can co-infect host cells in vitro, the super infection rates are low, specially as the time between the primary infection and super infection increases. These results confirm the occurrence of super infection exclusion between different strains of NDV.

  4. Label-free imaging of brain and brain tumor specimens with combined two-photon excited fluorescence and second harmonic generation microscopy

    Science.gov (United States)

    Jiang, Liwei; Wang, Xingfu; Wu, Zanyi; Du, Huiping; Wang, Shu; Li, Lianhuang; Fang, Na; Lin, Peihua; Chen, Jianxin; Kang, Dezhi; Zhuo, Shuangmu

    2017-10-01

    Label-free imaging techniques are gaining acceptance within the medical imaging field, including brain imaging, because they have the potential to be applied to intraoperative in situ identifications of pathological conditions. In this paper, we describe the use of two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) microscopy in combination for the label-free detection of brain and brain tumor specimens; gliomas. Two independently detecting channels were chosen to subsequently collect TPEF/SHG signals from the specimen to increase TPEF/SHG image contrasts. Our results indicate that the combined TPEF/SHG microscopic techniques can provide similar rat brain structural information and produce a similar resolution like conventional H&E staining in neuropathology; including meninges, cerebral cortex, white-matter structure corpus callosum, choroid plexus, hippocampus, striatum, and cerebellar cortex. It can simultaneously detect infiltrating human brain tumor cells, the extracellular matrix collagen fiber of connective stroma within brain vessels and collagen depostion in tumor microenvironments. The nuclear-to-cytoplasmic ratio and collagen content can be extracted as quantitative indicators for differentiating brain gliomas from healthy brain tissues. With the development of two-photon fiberscopes and microendoscope probes and their clinical applications, the combined TPEF and SHG microcopy may become an important multimodal, nonlinear optical imaging approach for real-time intraoperative histological diagnostics of residual brain tumors. These occur in various brain regions during ongoing surgeries through the method of simultaneously identifying tumor cells, and the change of tumor microenvironments, without the need for the removal biopsies and without the need for tissue labelling or fluorescent markers.

  5. Generation and characterization of transgenic mice expressing mitochondrial targeted red fluorescent protein selectively in neurons: modeling mitochondriopathy in excitotoxicity and amyotrophic lateral sclerosis

    Directory of Open Access Journals (Sweden)

    Wang Yi

    2011-11-01

    Full Text Available Abstract Background Mitochondria have roles or appear to have roles in the pathogenesis of several chronic age-related and acute neurological disorders, including Charcot-Marie-Tooth disease, amyotrophic lateral sclerosis, Parkinson's disease, and cerebral ischemia, and could be critical targets for development of rational mechanism-based, disease-modifying therapeutics for treating these disorders effectively. A deeper understanding of neural tissue mitochondria pathobiologies as definitive mediators of neural injury, disease, and cell death merits further study, and the development of additional tools to study neural mitochondria will help achieve this unmet need. Results We created transgenic mice that express the coral (Discosoma sp. red fluorescent protein DsRed2 specifically in mitochondria of neurons using a construct engineered with a Thy1 promoter, specific for neuron expression, to drive expression of a fusion protein of DsRed2 with a mitochondrial targeting sequence. The biochemical and histological characterization of these mice shows the expression of mitochondrial-targeted DsRed2 to be specific for mitochondria and concentrated in distinct CNS regions, including cerebral cortex, hippocampus, thalamus, brainstem, and spinal cord. Red fluorescent mitochondria were visualized in cerebral cortical and hippocampal pyramidal neurons, ventrobasal thalamic neurons, subthalamic neurons, and spinal motor neurons. For the purpose of proof of principle application, these mice were used in excitotoxicity paradigms and double transgenic mice were generated by crossing Thy1-mitoDsRed2 mice with transgenic mice expressing enhanced-GFP (eGFP under the control of the Hlxb9 promoter that drives eGFP expression specifically in motor neurons and by crossing Thy1-mitoDsRed2 mice to amyotrophic lateral sclerosis (ALS mice expressing human mutant superoxide dismutase-1. Conclusions These novel transgenic mice will be a useful tool for better understanding

  6. Highly thermostable fluorescent proteins

    Science.gov (United States)

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

    2012-05-01

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

  7. Highly thermostable fluorescent proteins

    Science.gov (United States)

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

    2011-03-22

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

  8. 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...

  9. 76 FR 29277 - Exelon Generation Company, LLC; Peach Bottom Atomic Power Station Unit Nos. 2 and 3...

    Science.gov (United States)

    2011-05-20

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY... Assessment and Finding of No Significant Impact The U.S. Nuclear Regulatory Commission (NRC) is considering... waste (LLRW), from Exelon's Limerick Generating Station, Units 1 and 2 (LGS). The LLRW will be stored in...

  10. Visible light generation of iodine atoms and I-I bonds: sensitized I(-) oxidation and I(3)(-) photodissociation.

    Science.gov (United States)

    Gardner, James M; Abrahamsson, Maria; Farnum, Byron H; Meyer, Gerald J

    2009-11-11

    Direct 355 or 532 nm light excitation of TBAI(3), where TBA is tetrabutyl ammonium, in CH(3)CN at room temperature yields an iodine atom, I(*), and an iodine radical anion, I(2)(-*). In the presence of excess iodide, the iodine atom reacts quantitatively to yield a second equivalent of I(2)(-*) with a rate constant of k = 2.5 +/- 0.4 x 10(10) M(-1) s(-1). The I(2)(-*) intermediates are unstable with respect to disproportionation and yield initial reactants, k = 3.3 +/- 0.1 x 10(9) M(-1) s(-1). The coordination compound Ru(bpz)(2)(deeb)(PF(6))(2), where bpz is 2,2'-bipyrazine and deeb is 4,4'-(C(2)H(5)CO(2))(2)-2,2'-bipyridine, was prepared and characterized for mechanistic studies of iodide photo-oxidation in acetonitrile at room temperature. Ru(bpz)(2)(deeb)(2+) displayed a broad metal-to-ligand charge transfer (MLCT) absorption band at 450 nm with epsilon = 1.7 x 10(4) M(-1) cm(-1). Visible light excitation resulted in photoluminescence with a corrected maximum at 620 nm, a quantum yield phi = 0.14, and an excited state lifetime tau = 1.75 micros from which k(r) = 8.36 x 10(4) s(-1) and k(nr) = 5.01 x 10(5) s(-1) were abstracted. Arrhenius analysis of the temperature dependent excited state lifetime revealed an activation energy of approximately 2500 cm(-1) and a pre-exponential factor of 10(10) s(-1), assigned to activated surface crossing to a ligand field or MLCT excited state. Steady state light excitation of Ru(bpz)(2)(deeb)(2+) in a 20 mM TBAI acetonitrile solution resulted in ligand loss photochemistry with a quantum yield of 5 x 10(-5). The MLCT excited state was dynamically quenched by iodide with K(sv) = 1.1 x 10(5) M(-1) and k(q) = 6.6 +/- 0.3 x 10(10) M(-1) s(-1), a value consistent with diffusion-limited electron transfer. Excited state hole transfer to iodide was quantitative but the product yield was low due to poor cage escape yields, phi(CE) = 0.042 +/- 0.001. Nanosecond transient absorption was used to quantify the appearance of two

  11. Generations.

    Science.gov (United States)

    Chambers, David W

    2005-01-01

    Groups naturally promote their strengths and prefer values and rules that give them an identity and an advantage. This shows up as generational tensions across cohorts who share common experiences, including common elders. Dramatic cultural events in America since 1925 can help create an understanding of the differing value structures of the Silents, the Boomers, Gen Xers, and the Millennials. Differences in how these generations see motivation and values, fundamental reality, relations with others, and work are presented, as are some applications of these differences to the dental profession.

  12. Observation of linewidth narrowing due to a spontaneously generated coherence effect

    Institute of Scientific and Technical Information of China (English)

    Tian Si-Cong; Gao Jin-Yue; Wang Chun-Liang; Kang Zhi-Hui; Yang Xiu-Bin; Wan Ren-Gang; Zhang Xiao-Jun; Zhang Hang; Jiang Yun; Cui Hai-Ning

    2012-01-01

    We investigate the resonance fluorescence spectrum of an atomic three-level ladder system driven by two laser fields.We show that such a system emulates to a large degree a V-type atom with parallel dipole moments—the latter being a system that exhibits spontaneously generated coherence and can display ultrasharp spectral lines.We find a suitable energy scheme in a 85Rb atom and experimentally observe the narrowing of the central peak in a rubidium atomic beam.The corresponding spectrum can convincingly demonstrate the existence of spontaneously generated coherence.

  13. 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.

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

    Institute of Scientific and Technical Information of China (English)

    王杰英; 刘贝; 刁文婷; 靳刚; 何军; 王军民

    2014-01-01

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

  15. The role of Rydberg and continuum levels in computing high harmonic generation spectra of the hydrogen atom using time-dependent configuration interaction.

    Science.gov (United States)

    Luppi, Eleonora; Head-Gordon, Martin

    2013-10-28

    We study the role of Rydberg bound-states and continuum levels in the field-induced electronic dynamics associated with the High-Harmonic Generation (HHG) spectroscopy of the hydrogen atom. Time-dependent configuration-interaction (TD-CI) is used with very large atomic orbital (AO) expansions (up to L = 4 with sextuple augmentation and off-center functions) to describe the bound Rydberg levels, and some continuum levels. To address the lack of ionization losses in TD-CI with finite AO basis sets, we employed a heuristic lifetime for energy levels above the ionization potential. The heuristic lifetime model is compared against the conventional atomic orbital treatment (infinite lifetimes), and a third approximation which is TD-CI using only the bound levels (continuum lifetimes go to zero). The results suggest that spectra calculated using conventional TD-CI do not converge with increasing AO basis set size, while the zero lifetime and heuristic lifetime models converge to qualitatively similar spectra, with implications for how best to apply bound state electronic structure methods to simulate HHG. The origin of HHG spectral features including the cutoff and extent of interference between peaks is uncovered by separating field-induced coupling between different types of levels (ground state, bound Rydberg levels, and continuum) in the simulated electronic dynamics. Thus the origin of deviations between the predictions of the semi-classical three step model and the full simulation can be associated with particular physical contributions, which helps to explain both the successes and the limitations of the three step model.

  16. Electrochemical generation of arsenic volatile species using a gold/mercury amalgam cathode. Determination of arsenic by atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Andrea Caiminagua

    2015-03-01

    Full Text Available The electrochemical generation of arsenic volatile species (arsine using an Au/Hg amalgam cathode in a 0.5 M H2SO4 solution, is described. Results were compared with those obtained with other cathodes commonly used for generation of arsine. The effects of the electrolytic conditions and interferent ions have been studied. Results show that the Au/Hg cathode has better tolerance to interference and higher repeatability than cathodes made out of platinum (Pt, gold (Au, reticulated glassy carbon (RGC, lead (Pb. Under optimized conditions, a 0.027 μg L−1 (3σ detection limit for As(III in aqueous solutions and a 2.4% relative standard deviation for a 0.1 μg L−1 As(III were obtained. The accuracy of the method was verified by determination of As in a certified reference material. The proposed method was applied to the determination of As in spiked tap water samples.

  17. Tracking Changes in Absorptivity, Stiffness, and Organic Chemical Composition in Laboratory Generated HULIS SOA using Atomic Force Microscopy and X-ray Microscopy

    Science.gov (United States)

    Hawkins, L. N.; Lemire, A.; Kong, W.

    2014-12-01

    Light absorbing organic compounds are among the many products of aqueous phase secondary organic aerosol formation. Once formed, these compounds can alter the optical and material properties of SOA in ways that impact their ability to scatter and absorb solar radiation, deliquesce and evaporate quickly during cloud cycling, and react with gas phase species such as oxidants. To quantify these effects, we have characterized the changes in UV-visible absorption, stiffness, and particle shape that occur when aqueous SOA is exposed to repeated wet-dry cycles and photooxidation. Material properties were measured with Atomic Force Microscopy of atomized laboratory generated SOA; this material was created by combining glyoxal, methylglyoxal, or glycolaldehyde with ammonium sulfate, glycine, or methylamine in solution and either spray drying or evaporating the bulk solution. In addition to optical and material properties, changes in organic functional groups were tracked using scanning transmission x-ray microscopy (STXM) of the near carbon edge x-ray absorption fine structure (NEXAFS). Photooxidation experiments of the same aqueous SOA revealed concomitant changes in the organic functional groups and light absorption spectra, along with measurable changes in particle stiffness.

  18. Efficient generation of human embryonic stem cell-derived cardiac progenitors based on tissue-specific enhanced green fluorescence protein expression.

    Science.gov (United States)

    Szebényi, Kornélia; Péntek, Adrienn; Erdei, Zsuzsa; Várady, György; Orbán, Tamás I; Sarkadi, Balázs; Apáti, Ágota

    2015-01-01

    Cardiac progenitor cells (CPCs) are committed to the cardiac lineage but retain their proliferative capacity before becoming quiescent mature cardiomyocytes (CMs). In medical therapy and research, the use of human pluripotent stem cell-derived CPCs would have several advantages compared with mature CMs, as the progenitors show better engraftment into existing heart tissues, and provide unique potential for cardiovascular developmental as well as for pharmacological studies. Here, we demonstrate that the CAG promoter-driven enhanced green fluorescence protein (EGFP) reporter system enables the identification and isolation of embryonic stem cell-derived CPCs. Tracing of CPCs during differentiation confirmed up-regulation of surface markers, previously described to identify cardiac precursors and early CMs. Isolated CPCs express cardiac lineage-specific transcripts, still have proliferating capacity, and can be re-aggregated into embryoid body-like structures (CAG-EGFP(high) rEBs). Expression of troponin T and NKX2.5 mRNA is up-regulated in long-term cultured CAG-EGFP(high) rEBs, in which more than 90% of the cells become Troponin I positive mature CMs. Moreover, about one third of the CAG-EGFP(high) rEBs show spontaneous contractions. The method described here provides a powerful tool to generate expandable cultures of pure human CPCs that can be used for exploring early markers of the cardiac lineage, as well as for drug screening or tissue engineering applications.

  19. Quantification of factors influencing fluorescent protein expression using RMCE to generate an allelic series in the ROSA26 locus in mice

    Directory of Open Access Journals (Sweden)

    Sara X. Chen

    2011-07-01

    Fluorescent proteins (FPs have great utility in identifying specific cell populations and in studying cellular dynamics in the mouse. To quantify the factors that determine both the expression and relative brightness of FPs in mouse embryonic stem cells (mESCs and in mice, we generated eight different FP-expressing ROSA26 alleles using recombinase-mediated cassette exchange (RMCE. These alleles enabled us to analyze the effects on FP expression of a translational enhancer and different 3′-intronic and/or polyadenylation sequences, as well as the relative brightness of five different FPs, without the confounding position and copy number effects that are typically associated with randomly inserted transgenes. We found that the expression of a given FP can vary threefold or more depending on the genetic features present in the allele. The optimal FP expression cassette contained both a translational enhancer sequence in the 5′-untranslated region (UTR and an intron-containing rabbit β-globin sequence within the 3′-UTR. The relative expressed brightness of individual FPs varied up to tenfold. Of the five different monomeric FPs tested, Citrine (YFP was the brightest, followed by Apple, eGFP, Cerulean (CFP and Cherry. Generation of a line of Cherry-expressing mice showed that there was a 30-fold variation of Cherry expression among different tissues and that there was a punctate expression pattern within cells of all tissues examined. This study should help investigators make better-informed design choices when expressing FPs in mESCs and mice.

  20. What is limiting low-temperature atomic layer deposition of Al{sub 2}O{sub 3}? A vibrational sum-frequency generation study

    Energy Technology Data Exchange (ETDEWEB)

    Vandalon, V., E-mail: v.vandalon@tue.nl, E-mail: w.m.m.kessels@tue.nl; Kessels, W. M. M., E-mail: v.vandalon@tue.nl, E-mail: w.m.m.kessels@tue.nl [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2016-01-04

    The surface reactions during atomic layer deposition (ALD) of Al{sub 2}O{sub 3} from Al(CH{sub 3}){sub 3} and H{sub 2}O have been studied with broadband sum-frequency generation to reveal what is limiting the growth at low temperatures. The –CH{sub 3} surface coverage was measured for temperatures between 100 and 300 °C and the absolute reaction cross sections, describing the reaction kinetics, were determined for both half-cycles. It was found that –CH{sub 3} groups persisted on the surface after saturation of the H{sub 2}O half-cycle. From a direct correlation with the growth per cycle, it was established that the reduced reactivity of H{sub 2}O towards –CH{sub 3} is the dominant factor limiting the ALD process at low temperatures.