Science.gov

Sample records for micro-raman analysis application

  1. Micro-Raman analysis of titanium oxide/carbon nanotubes-based nanocomposites for hydrogen sensing applications

    SciTech Connect

    Santangelo, S.; Messina, G.; Faggio, G.; Donato, A.; De Luca, L.; Donato, N.; Bonavita, A.; Neri, G.

    2010-10-15

    Titanium oxide/carbon nanotubes-based nanocomposites (TiO{sub 2}/CNTs, prepared by sol-gel method, and 2%Pt/TiO{sub 2}/CNTs, obtained by wetness impregnation of the TiO{sub 2}/CNTs base material with a solution of platinum acetylacetonate) have been recently used as active layer in hydrogen sensing devices at near room temperature, obtaining quite different responsiveness. The microstructure of these hybrid materials is here systematically investigated by micro-Raman spectroscopy at 2.41 eV. The results show that regardless of the nominal C/Ti molar ratio (3.6 or 17.0) only the anatase phase of titania is formed. Theoretical calculations demonstrate that phonon confinement is fully responsible for the large blue-shift ({approx}10 cm{sup -1}) and broadening ({approx}20 cm{sup -1}) of the lowest-frequency Raman mode with respect to bulk anatase. The average size (4.3-5.0 nm) of TiO{sub 2} crystallites, resulting from Raman spectra fitting, is in excellent agreement with those inferred from transmission electron microscopy and X-ray diffraction measurements. - Graphical Abstract: Micro-Raman analysis of TiO{sub 2}/CNTs and Pt/TiO{sub 2}/CNTs hybrids for H{sub 2} sensing applications evidences that regardless of C/Ti molar ratio titania crystallizes in the anatase phase. The very small size of TiO{sub 2} crystallites (4.3-5.0 nm) is responsible for the observed phonon confinement effects.

  2. Calibration of Carbonate Composition Using Micro-Raman Analysis: Application to Planetary Surface Exploration

    NASA Astrophysics Data System (ADS)

    Rividi, Nicolas; van Zuilen, Mark; Philippot, Pascal; Ménez, Bénédicte; Godard, Gaston; Poidatz, Emmanuel

    2010-04-01

    Stromatolite structures in Early Archean carbonate deposits form an important clue for the existence of life in the earliest part of Earth's history. Since Mars is thought to have had similar environmental conditions early in its history, the question arises as to whether such stromatolite structures also evolved there. Here, we explore the capability of Raman spectroscopy to make semiquantitative estimates of solid solutions in the Ca-Mg-Fe(+Mn) carbonate system, and we assess its use as a rover-based technique for stromatolite characterization during future Mars missions. Raman microspectroscopy analysis was performed on a set of carbonate standards (calcite, ankerite, dolomite, siderite, and magnesite) of known composition. We show that Raman band shifts of siderite-magnesite and ankerite-dolomite solid solutions display a well-defined positive correlation (r2 > 0.9) with the Mg# = 100 × Mg/(Mg + Fe + Mn + Ca) of the carbonate analyzed. Raman shifts calibrated as a function of Mg# were used in turn to evaluate the chemical composition of carbonates. Raman analysis of a suite of carbonates (siderite, sidero-magnesite, ankerite, and dolomite) of hydrothermal and sedimentary origin from the ca. 3.2 Ga old Barite Syncline, Barberton greenstone belt, South Africa, and from the ca. 3.5 Ga old Dresser Formation, Pilbara Craton, Western Australia, show good compositional agreement with electron microprobe analyses. These results indicate that Raman spectroscopy can provide direct information on the composition and structure of carbonates on planetary surfaces.

  3. Calibration of carbonate composition using micro-Raman analysis: application to planetary surface exploration.

    PubMed

    Rividi, Nicolas; van Zuilen, Mark; Philippot, Pascal; Ménez, Bénédicte; Godard, Gaston; Poidatz, Emmanuel

    2010-04-01

    Stromatolite structures in Early Archean carbonate deposits form an important clue for the existence of life in the earliest part of Earth's history. Since Mars is thought to have had similar environmental conditions early in its history, the question arises as to whether such stromatolite structures also evolved there. Here, we explore the capability of Raman spectroscopy to make semiquantitative estimates of solid solutions in the Ca-Mg-Fe(+Mn) carbonate system, and we assess its use as a rover-based technique for stromatolite characterization during future Mars missions. Raman microspectroscopy analysis was performed on a set of carbonate standards (calcite, ankerite, dolomite, siderite, and magnesite) of known composition. We show that Raman band shifts of siderite-magnesite and ankerite-dolomite solid solutions display a well-defined positive correlation (r(2) > 0.9) with the Mg# = 100 x Mg/(Mg + Fe + Mn + Ca) of the carbonate analyzed. Raman shifts calibrated as a function of Mg# were used in turn to evaluate the chemical composition of carbonates. Raman analysis of a suite of carbonates (siderite, sidero-magnesite, ankerite, and dolomite) of hydrothermal and sedimentary origin from the ca. 3.2 Ga old Barite Syncline, Barberton greenstone belt, South Africa, and from the ca. 3.5 Ga old Dresser Formation, Pilbara Craton, Western Australia, show good compositional agreement with electron microprobe analyses. These results indicate that Raman spectroscopy can provide direct information on the composition and structure of carbonates on planetary surfaces. PMID:20446870

  4. Micro-Raman Analysis of Irradiated Diamond Films

    NASA Technical Reports Server (NTRS)

    Newton, R. L.; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    Owing to its unique and robust physical properties, diamond is a much sought after material for use in advanced technologies such as Microelectromechanical Systems (MEMS). The volume and weight savings promised by MEMS-based devices are of particular interest to spaceflight applications. However, much basic materials science research remains to be completed in this field. Results of micro-Raman analysis of proton (1015 - 1017 H+/cm2 doses) irradiated chemical vapor deposited (CVD) diamond reveals that the microstructure is retained even after high radiation exposure.

  5. Micro-Raman Analysis of Irradiated Diamond Films

    NASA Technical Reports Server (NTRS)

    Newton, Robert L.

    2003-01-01

    Owing to its unique and robust physical properties, diamond is a much sought after material for use in advanced technologies, even in Microelectromechanical Systems (MEMS). The volume and weight savings promised by MEMS-based devices are of particular interest to spaceflight applications. However, much basic materials science research remains to be completed in this field. Results of micro-Raman analysis of proton (10(exp 15) - 10(exp 17) H(+)/sq cm doses) irradiated chemical vapor deposited (CVD) films are presented and indicate that their microstructure is retained even after high radiation exposure.

  6. Micro-Raman analysis of titanium oxide/carbon nanotubes-based nanocomposites for hydrogen sensing applications

    NASA Astrophysics Data System (ADS)

    Santangelo, S.; Messina, G.; Faggio, G.; Donato, A.; De Luca, L.; Donato, N.; Bonavita, A.; Neri, G.

    2010-10-01

    Titanium oxide/carbon nanotubes-based nanocomposites (TiO 2/CNTs, prepared by sol-gel method, and 2%Pt/TiO 2/CNTs, obtained by wetness impregnation of the TiO 2/CNTs base material with a solution of platinum acetylacetonate) have been recently used as active layer in hydrogen sensing devices at near room temperature, obtaining quite different responsiveness. The microstructure of these hybrid materials is here systematically investigated by micro-Raman spectroscopy at 2.41 eV. The results show that regardless of the nominal C/Ti molar ratio (3.6 or 17.0) only the anatase phase of titania is formed. Theoretical calculations demonstrate that phonon confinement is fully responsible for the large blue-shift (˜10 cm -1) and broadening (˜20 cm -1) of the lowest-frequency Raman mode with respect to bulk anatase. The average size (4.3-5.0 nm) of TiO 2 crystallites, resulting from Raman spectra fitting, is in excellent agreement with those inferred from transmission electron microscopy and X-ray diffraction measurements.

  7. Analysis of Individual Cells and Endospores by Micro-Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Esposito, Anthony; Huser, Thomas; Talley, Chad; Hollars, Christopher; Balhorn, Rod; Lane, Stephen

    2003-03-01

    We have collected Raman spectra of individual sperm cells by confocal micro-Raman spectroscopy. The high spatial resolution of this technique allows for compositional analysis of different sections of the sperm cells. The relative intensities of protein and DNA Raman transitions allow one to define a protein-DNA ratio. We have also collected the Raman spectra of individual bacterial endospores from four species in the genus Bacillus. The spectra were generally dominated by scattering from calcium dipicolinate, although scattering assignable to protein bands was also observed. A small fraction of the spores did not exhibit Raman scattering from CaDPA, possibly due to incomplete sporulation. These examples demonstrate the applicability of micro-Raman spectroscopy as a non-invasive method for addressing variability in the composition of cells.* *This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract number W-7405-Eng-48.

  8. Oral pathology follow-up by means of micro-Raman spectroscopy on tissue and blood serum samples: an application of wavelet and multivariate data analysis

    NASA Astrophysics Data System (ADS)

    Delfino, I.; Camerlingo, C.; Zenone, F.; Perna, G.; Capozzi, V.; Cirillo, N.; Gaeta, G. M.; De Mol, E.; Lepore, M.

    2009-02-01

    Pemphigus vulgaris (PV) is a potentially fatal autoimmune disease that cause blistering of the skin and oral cavity. It is characterized by disruption of cell-cell adhesion within the suprabasal layers of epithelium, a phenomenon termed acantholysis Patients with PV develop IgG autoantibodies against normal constituents of the intercellular substance of keratinocytes. The mechanisms by which such autoantibodies induce blisters are not clearly understood. The qualitative analysis of such effects provides important clues in the search for a specific diagnosis, and the quantitative analysis of biochemical abnormalities is important in measuring the extent of the disease process, designing therapy and evaluating the efficacy of treatment. Improved diagnostic techniques could permit the recognition of more subtle forms of disease and reveal incipient lesions clinically unapparent, so that progression of potentially severe forms could be reversed with appropriate treatment. In this paper, we report the results of our micro-Raman spectroscopy study on tissue and blood serum samples from ill, recovered and under therapy PV patients. The complexity of the differences among their characteristic Raman spectra has required a specific strategy to obtain reliable information on the illness stage of the patients For this purpose, wavelet techniques and advanced multivariate analysis methods have been developed and applied to the experimental Raman spectra. Promising results have been obtained.

  9. Wavelet data analysis of micro-Raman spectra for follow-up monitoring in oral pathologies

    NASA Astrophysics Data System (ADS)

    Camerlingo, C.; Zenone, F.; Perna, G.; Capozzi, V.; Cirillo, N.; Gaeta, G. M.; Lepore, M.

    2008-02-01

    A wavelet multi-component decomposition algorithm has been used for data analysis of micro-Raman spectra from human biological samples. In particular, measurements have been performed on some samples of oral tissue and blood serum from patients affected by pemphigus vulgaris at different stages. Pemphigus is a chronic, autoimmune, blistering disease of the skin and mucous membranes with a potentially fatal outcome. The disease is characterized histologically by intradermal blisters and immunopathologically by the finding of tissue bound and circulating immunoglobulin G (IgG) antibody directed against the cell surface of keratinocytes. More than 150 spectra were measured by means of a Raman confocal microspectrometer apparatus using the 632.8 nm line of a He-Ne laser source. A discrete wavelet transform decomposition method has been applied to the recorded Raman spectra in order to overcome related to low-level signals and the presence of noise and background components due to light scattering and fluorescence. The results indicate that appropriate data processing can contribute to enlarge the medical applications of micro-Raman spectroscopy.

  10. Quantitative micro-Raman analysis of volcanic glasses: influence and correction of matrix effects

    NASA Astrophysics Data System (ADS)

    Di Muro, Andrea

    2014-05-01

    . Geochimica et Cosmochimica Acta, 74, 5641-5656. Mercier, M., Di Muro, A., Giordano, D., Métrich, N.,Pichavant, M., Clocchiatti, R., Montagnac, G. (2009) The influence of glass polymerization and oxidation on micro-Raman water analysis in alumino-silicate glasses. Geochimica et Cosmochimica Acta, 73, 197-217 Di Muro, A., Métrich, N., Mercier, M., Giordano, D., Massare, D., Montagnac, G. (2009) Micro-Raman determination of iron redox state in dry natural glasses : application to peralkaline rhyolites and basalts. Chemical Geology (Special volume on experimental techniques for the study of hydrothermal fluids and silicate melts) 259:78-88. Di Muro A, Villemant B, Montagnac G, Scaillet B, Reynard B (2006) The influence of glass composition on the determination of water content and speciation by Raman spectrometry. Geochimica and Cosmochimica Acta, 70, 2868-2884 Di Muro A, Giordano D., Villemant B, Montagnac G, Romano C. (2006) Influence of composition and thermal history of volcanic glasses on water content determination by microRaman spectrometry. Applied Geochemistry (Special volume on developments in analytical geochemistry). 21, 802-812. Application Di Muro, A., Staudacher, T., Ferrazzini, V., Villemant, B., Besson, P., Garofalo, C. (2014) Tracking magma injection in the Piton de la Fournaise volcanic edifice after the 2007 Summit Caldera Collapse by Pele's Hair Composition. Chapman Special Volume on Hawaiian volcanoes, AGU Books. Ardia, P., Di Muro, A., Giordano, D., Massare, D., Sanchez-Valle, C., Schmidt, M.W. (2014) Densification mechanisms of haplogranite glasses as a function of water content and pressure based on density and Raman data. Under review, submitted to Geochimica et Cosmochimica Acta. Métrich, N, Allard, P., Aiuppa, A., Bani, P., Bertagnini, A., Belhadj, O., Di Muro, A., Garaebiti, E., Massare, D., Parello, F., Shinohara, H. (2011) Magma and volatile feeding of post-caldera Yasur volcanism and block resurgence in Tanna island (Vanuatu arc). Journal of

  11. Study on the strain in a silicon microchannel plate by micro-Raman analysis

    NASA Astrophysics Data System (ADS)

    Xu, Shaohui; Fang, Jiabing; Wu, Dajun; Zhang, Chi; Zhu, Yiping; Xiong, Dayuan; Wang, Lianwei; Yang, Pingxiong; Chu, Paul K.

    2016-05-01

    Micro-Raman analysis was used to identify the oxidation of a silicon microchannel plate (SiMCP) and it indicated that the bend phenomenon of the SiMCP was related to the release of stress and the volume expending of the silicon wall during the oxidation process.

  12. Quantitative micro-Raman analysis of volcanic glasses: influence and correction of matrix effects

    NASA Astrophysics Data System (ADS)

    Di Muro, Andrea

    2014-05-01

    . Geochimica et Cosmochimica Acta, 74, 5641-5656. Mercier, M., Di Muro, A., Giordano, D., Métrich, N.,Pichavant, M., Clocchiatti, R., Montagnac, G. (2009) The influence of glass polymerization and oxidation on micro-Raman water analysis in alumino-silicate glasses. Geochimica et Cosmochimica Acta, 73, 197-217 Di Muro, A., Métrich, N., Mercier, M., Giordano, D., Massare, D., Montagnac, G. (2009) Micro-Raman determination of iron redox state in dry natural glasses : application to peralkaline rhyolites and basalts. Chemical Geology (Special volume on experimental techniques for the study of hydrothermal fluids and silicate melts) 259:78-88. Di Muro A, Villemant B, Montagnac G, Scaillet B, Reynard B (2006) The influence of glass composition on the determination of water content and speciation by Raman spectrometry. Geochimica and Cosmochimica Acta, 70, 2868-2884 Di Muro A, Giordano D., Villemant B, Montagnac G, Romano C. (2006) Influence of composition and thermal history of volcanic glasses on water content determination by microRaman spectrometry. Applied Geochemistry (Special volume on developments in analytical geochemistry). 21, 802-812. Application Di Muro, A., Staudacher, T., Ferrazzini, V., Villemant, B., Besson, P., Garofalo, C. (2014) Tracking magma injection in the Piton de la Fournaise volcanic edifice after the 2007 Summit Caldera Collapse by Pele's Hair Composition. Chapman Special Volume on Hawaiian volcanoes, AGU Books. Ardia, P., Di Muro, A., Giordano, D., Massare, D., Sanchez-Valle, C., Schmidt, M.W. (2014) Densification mechanisms of haplogranite glasses as a function of water content and pressure based on density and Raman data. Under review, submitted to Geochimica et Cosmochimica Acta. Métrich, N, Allard, P., Aiuppa, A., Bani, P., Bertagnini, A., Belhadj, O., Di Muro, A., Garaebiti, E., Massare, D., Parello, F., Shinohara, H. (2011) Magma and volatile feeding of post-caldera Yasur volcanism and block resurgence in Tanna island (Vanuatu arc). Journal of

  13. Micro-Raman spectroscopy: The analysis of micrometer and submicrometer atmospheric aerosols

    NASA Technical Reports Server (NTRS)

    Klainer, S. M.; Milanovich, F. P.

    1985-01-01

    A nondestructive method of molecular analysis which is required to fully utilize the information contained within a collected particle is discussed. Upper atmosphere reaction mechanisms are assessed when the chemical compounds, the use of micro-Raman spectrometric techniques to perform micron and submicron particle analysis was evaluated. The results are favorable and it is concluded that micron and submicron particles can be analyzed by the micron-Raman approach. Completely automatic analysis should be possible to 0.3 micro m. No problems are anticipated with photo or thermal decomposition. Sample and impurity fluorescence are the key source of background as they cannot be completely eliminated.

  14. Application of micro-Raman and Photoluminescence spectroscopy to defect and thin film characterization

    NASA Astrophysics Data System (ADS)

    Conti, Giuseppina; Uritsky, Yuri; Brundle, C. R.

    2001-01-01

    Applications of micro-Raman and micro-Photoluminescence spectroscopy to defect and thin film characterization in semiconductor processing and equipment development are presented. The Raman spectrometer is coupled to a confocal laser Defect Review Tool (DRT). This system locates particles as small as 0.2 μm, both on 200 mm and 300 mm wafers. Raman spectroscopy is fast, non-destructive, can be performed in ambient, and is capable of providing chemical state and structural (phases, stress) information down to sub-micron dimension. Its application is material specific, however, since some materials do not have Raman-active vibrations or sufficient cross-section, or have a probing depth too long (optically transparent) to be useful. In general, chemical state information is obtainable from vibrational fingerprints of covalently bonded compounds (organic, Si-H, Si-Si, etc.), some ceramics (e.g. Zr-O, Al-O etc.), and ionic species (e.g. ammonium salts). Structural information, such as residual stress (e.g. poly-Si) and phase distinction (e.g. amorphous/diamond carbon; high/low residual phases of silicide) can sometimes also be obtained. Specific examples from Applied Materials development programs are presented. These include identification and distinction of carbon particles from different hardware sources generated by NF3 clean; organic defects on Cu after CMP; identification of the compound causing Br based particles after poly-gate etch; and distinction between ceramic based aluminum particles and anodized based aluminum particles. In the area of thin film characterization we have used micro-Raman to characterize residual build-up on hardware (e.g. residue from showerhead used in the W-CVD process chamber), and the process development of coatings and film products (e.g. diamond, poly-Si).

  15. Assessment of conjunctival microvilli abnormality by micro-Raman analysis - by G. Rusciano et al.

    PubMed

    Rusciano, Giulia; Zito, Gianluigi; Pesce, Giuseppe; Del Prete, Salvatore; Cennamo, Gilda; Sasso, Antonio

    2016-05-01

    Conjunctival microvilli are microscopic cellular membrane protrusions on apical epithelial cells, which increase the surface area available for tear adherence. Pathological alterations of microvilli structure affect the tear film stability and, conversely, dysfunctions of tear film composition can lead to a suffering epithelium (dry-eye syndrome). In this work we propose the use of micro-Raman analysis to reveal conjunctival microvilli abnormalities. Samples were obtained by impression cytology from patients by different stage of dry-eye syndrome. Our experimental outcomes demonstrate that Raman analysis, combined with the use of Principal Component Analysis, is able to detect different stages of microvilli reduction. Globally, these results hold promise for the use of Raman analysis for an objective, effective, non-invasive and potentially also in-vivo analysis of the conjunctiva in all the cases of microvilli-related ocular pathologies. PMID:26876569

  16. Near-infrared confocal micro-Raman spectroscopy combined with PCA-LDA multivariate analysis for detection of esophageal cancer

    NASA Astrophysics Data System (ADS)

    Chen, Long; Wang, Yue; Liu, Nenrong; Lin, Duo; Weng, Cuncheng; Zhang, Jixue; Zhu, Lihuan; Chen, Weisheng; Chen, Rong; Feng, Shangyuan

    2013-06-01

    The diagnostic capability of using tissue intrinsic micro-Raman signals to obtain biochemical information from human esophageal tissue is presented in this paper. Near-infrared micro-Raman spectroscopy combined with multivariate analysis was applied for discrimination of esophageal cancer tissue from normal tissue samples. Micro-Raman spectroscopy measurements were performed on 54 esophageal cancer tissues and 55 normal tissues in the 400-1750 cm-1 range. The mean Raman spectra showed significant differences between the two groups. Tentative assignments of the Raman bands in the measured tissue spectra suggested some changes in protein structure, a decrease in the relative amount of lactose, and increases in the percentages of tryptophan, collagen and phenylalanine content in esophageal cancer tissue as compared to those of a normal subject. The diagnostic algorithms based on principal component analysis (PCA) and linear discriminate analysis (LDA) achieved a diagnostic sensitivity of 87.0% and specificity of 70.9% for separating cancer from normal esophageal tissue samples. The result demonstrated that near-infrared micro-Raman spectroscopy combined with PCA-LDA analysis could be an effective and sensitive tool for identification of esophageal cancer.

  17. Rapid detection of Listeria monocytogenes in milk using confocal micro-Raman spectroscopy and chemometric analysis.

    PubMed

    Wang, Junping; Xie, Xinfang; Feng, Jinsong; Chen, Jessica C; Du, Xin-jun; Luo, Jiangzhao; Lu, Xiaonan; Wang, Shuo

    2015-07-01

    Listeria monocytogenes is a facultatively anaerobic, Gram-positive, rod-shape foodborne bacterium causing invasive infection, listeriosis, in susceptible populations. Rapid and high-throughput detection of this pathogen in dairy products is critical as milk and other dairy products have been implicated as food vehicles in several outbreaks. Here we evaluated confocal micro-Raman spectroscopy (785 nm laser) coupled with chemometric analysis to distinguish six closely related Listeria species, including L. monocytogenes, in both liquid media and milk. Raman spectra of different Listeria species and other bacteria (i.e., Staphylococcus aureus, Salmonella enterica and Escherichia coli) were collected to create two independent databases for detection in media and milk, respectively. Unsupervised chemometric models including principal component analysis and hierarchical cluster analysis were applied to differentiate L. monocytogenes from Listeria and other bacteria. To further evaluate the performance and reliability of unsupervised chemometric analyses, supervised chemometrics were performed, including two discriminant analyses (DA) and soft independent modeling of class analogies (SIMCA). By analyzing Raman spectra via two DA-based chemometric models, average identification accuracies of 97.78% and 98.33% for L. monocytogenes in media, and 95.28% and 96.11% in milk were obtained, respectively. SIMCA analysis also resulted in satisfied average classification accuracies (over 93% in both media and milk). This Raman spectroscopic-based detection of L. monocytogenes in media and milk can be finished within a few hours and requires no extensive sample preparation. PMID:25863337

  18. Micro-Raman and micro-XRF analysis of glass beads from the Chungde site, Taiwan

    NASA Astrophysics Data System (ADS)

    Liou, Y. S.; Wang, S. C.; Liu, Y. C.

    2014-12-01

    A large number of ancient glass beads dating back from Late Neolithic Age to early Historical Period (ca. 2300-400 BP) of Taiwan have been uncovered from archaeological sites. These glass beads with variant colors, shapes, and stylistics have long been considered to possess socio-cultural significance. Due to the color and chemical composition of glass bead might be determined by raw materials, fluxing agents, colorants, opacifiers and stabilizers. In addition, ancient glass beads are rare and precious, non-destructive analysis has been employed to decipher about the provenances, manufacturing techniques, and exchange/trade routes. In this work, micro-Raman spectroscopy and micro X-ray fluorescent spectrometer (μ-XRF) were used to examine ten ancient glass beads excavated from the Chungde site, Hualien, Taiwan, dating back to 1500-800 BP, to unravel the mineralogical and chemical compositions. Micro Raman experimental results show that glass and anorthite glass are the main constituents accompanying with trace level of quartz, albite, siderite, ankerite, and amazonite. The Raman Index of Polymerization (Ip) indicate that the sintering temperature of the glass beads is in the range of 1000~1400°C. Furthermore, the chemical compositions are corresponding to the maximum stretching vibration peak wave number (νmax Si-O Stretching) and the maximum bending vibration peak wave number (δmax Si-O Bending), which are essentially consistent with that of the India-Pacific beads. The μ-XRF results indicate the presence of oxides including SiO2, Al2O3, Fe2O3, Na2O, K2O, CaO, MgO, SnO2, TiO2, CuO, etc., and could be classified to high aluminum of soda-lime glass system. According to ternary phase diagram analysis of CaO-K2O-Na2O and K2O-Al2O3-CaO, the ancient glass beads analyzed could be attributed to the India-Pacific beads, and is in accordance with that of Raman spectra. The combination of these facts leads to the conclusion that glass beads obtained from the Chungde

  19. Application of slope-polishing technique for depth profile of selenized CIGS by micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Kwon, Min-Su; Kang, Jeong-yoon; Kim, SeongYeon; Kim, JunHo; Jeon, Chan-Wook

    2016-08-01

    Micro-Raman analysis was carried out on two Cu(In,Ga)Se2 films to determine the location of the secondary phases, which were suspected of being formed during the selenization process of Cu-In-Ga metallic precursor films. A slope polishing technique using a dimple grinder was applied to physically expand the film thickness by several hundred fold, which allowed high resolution Raman analysis. Various secondary phases including CuxSe, InSe, Se, and MoySe at different depths were identified without need for time-consuming sputter etching, which may adversely affect the film chemistry. With the help of the new sample preparation method for depth analysis of thin film, a precise decision on the location of those secondary phases along the film thickness and better understanding of the reaction mechanism was enabled.

  20. Phase transitions induced by shock compression on a gypsum mineral: X-ray and micro-Raman analysis

    NASA Astrophysics Data System (ADS)

    Bucio, L.; Rosales, I.; Thions, C.; Soullard, J.; Orozco, E.

    2015-10-01

    As a part of systematic researches of phase transitions induced by shock compression in phosphates, silicates, germanates and sulfates, in this article we report preliminary results obtained from shock recovery experiments on powders of a gypsum mineral. The shock experiment was performed in a light gas gun until a pressure close to 14 GPa reached. The experimental techniques employed to analyze the shock effects on recovered samples were: Scanning Electron Microscopy (SEM), X-ray Powder Diffraction (XRD) and Micro-Raman Spectroscopy (MRS). The SEM observations show a high plasticity in the impacted sample composed mainly by gypsum and bassanite quantified by Rietveld analysis of the XRD. The results indicate the partial dehydration of gypsum as a result of impact. The MRS analysis suggests the presence of micro-mixtures of gypsum, bassanite and anhydrite heterogeneously distributed throughout the recovered sample.

  1. Combined use of direct analysis in real-time/Orbitrap mass spectrometry and micro-Raman spectroscopy for the comprehensive characterization of real explosive samples.

    PubMed

    Bridoux, Maxime C; Schwarzenberg, Adrián; Schramm, Sébastien; Cole, Richard B

    2016-08-01

    Direct Analysis in Real Time (DART™) high-resolution Orbitrap™ mass spectrometry (HRMS) in combination with Raman microscopy was used for the detailed molecular level characterization of explosives including not only the charge but also the complex matrix of binders, plasticizers, polymers, and other possible organic additives. A total of 15 defused military weapons including grenades, mines, rockets, submunitions, and mortars were examined. Swabs and wipes were used to collect trace (residual) amounts of explosives and their organic constituents from the defused military weapons and micrometer-size explosive particles were transferred using a vacuum suction-impact collection device (vacuum impactor) from wipe and swap samples to an impaction plate made of carbon. The particles deposited on the carbon plate were then characterized using micro-Raman spectroscopy followed by DART-HRMS providing fingerprint signatures of orthogonal nature. The optical microscope of the micro-Raman spectrometer was first used to localize and characterize the explosive charge on the impaction plate which was then targeted for identification by DART-HRMS analysis in both the negative and positive modes. Raman spectra of the explosives TNT, RDX and PETN were acquired from micrometer size particles and characterized by the presence of their characteristic Raman bands obtained directly at the surface of the impaction plate nondestructively without further sample preparation. Negative mode DART-HRMS confirmed the types of charges contained in the weapons (mainly TNT, RDX, HMX, and PETN; either as individual components or as mixtures). These energetic compounds were mainly detected as deprotonated species [M-H](-), or as adduct [M + (35)Cl](-), [M + (37)Cl](-), or [M + NO3](-) anions. Chloride adducts were promoted in the heated DART reagent gas by adding chloroform vapors to the helium stream using an "in-house" delivery method. When the polarity was switched to positive mode

  2. Micro-Raman Spectroscopy to Complement Proton-Induced X-Ray Emission in the Analysis of Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Safiq, Alexandrea; Ali, Salina; Nadarski, Benjamin; Smith, Jeremy; Yoskowitz, Josh; Labrake, Scott; Vineyard, Michael; Union College Team

    2013-10-01

    There is an active research program in the Union College Ion-Beam Analysis Laboratory on proton-induced X-ray emission (PIXE) analysis of atmospheric aerosols. PIXE is a powerful tool for the study of airborne pollution because it provides information on a broad range of elements simultaneously, has low detection limits, is nondestructive, does not require large samples, and the analysis can be performed in a short amount of time. However, PIXE provides only elemental information. We are investigating the use of Micro-Raman spectroscopy (MRS) to complement PIXE analysis of aerosol samples by providing chemical information. In MRS, laser light is inelastically scattered from a sample and the vibrational spectrum of the scattered light is used to identify molecules and their functional groups. We are focusing on aerosol samples collected in the Adirondack Mountains that have considerable concentrations of sulfur that may contribute to acid rain. The MRS spectra collected on aerosol samples are being compared with a library of standards to try to determine the molecular structures in which the sulfur is bound. We will describe the analysis and present preliminary results. Union College Undergraduate Research Program.

  3. Application of micro-Raman spectroscopy for fight against terrorism and smuggling

    NASA Astrophysics Data System (ADS)

    Almaviva, Salvatore; Botti, Sabina; Palucci, Antonio; Puiu, Adriana; Schnürer, Frank; Schweikert, Wenka; Romolo, Francesco Saverio

    2014-04-01

    We report the results of Raman measurements on some common military explosives and explosives precursors deposited on clothing fabrics, both synthetic and natural, in concentration comparable to those obtained from a single fingerprint or mixed with similar harmless substances to detect illegal compounds for smuggling activities. Raman spectra were obtained using an integrated portable Raman system equipped with an optical microscope and a 785-nm laser in an analysis of <1 min. The spectral features of each illicit substance have been identified and distinguished from those belonging to the substrate fabric or from the interfering compound. Our results show that the application of Raman spectroscopy (RS) with a microscope-based portable apparatus can provide interpretable Raman spectra for a fast, in-situ analysis, directly from explosive particles of some μ, despite the contribution of the substrate, leaving the sample completely unaltered for further, more specific, and propedeutic laboratory analysis. We also show how the RS is suitable for detecting illegal compounds mixed with harmless substances for smuggling purposes or for counterfeiting activities.

  4. Evaluation of the Fiber Stress Distribution in Aramid/Epoxy Model Composite Using Micro-Raman Spectroscopy and FEM Analysis

    NASA Astrophysics Data System (ADS)

    Tanaka, Kazuto; Minoshima, Kohji; Yamada, Hideo

    A single-fiber pull-out model composite for an aramid/epoxy system was specially designed to measure the stress distribution of the aramid fiber embedded in the matrix using micro-Raman spectroscopy. The stress transfer length of the fiber obtained was about 400-500 μm, which was equal to the result of FEM analysis. Just after the initiation and propagation of the fiber/matrix interfacial debonding, the fiber was broken, and the fiber in the matrix had the axial tensile residual stress. The tensile residual axial stress showed the maximum at around the tip of the interfacial debonding. The stress was reduced after the specimen was kept in air at 80°C for 44h, and it became almost equal to zero after being immersed in deionized water at 80°C for 44h. This behavior agreed with the result of FEM analysis, in which the friction coefficient was introduced in the fiber/matrix interface. The axial residual stress was caused by the friction between the fiber and matrix, due to the compressive stress acting between the resin and the fiber, which was caused by the difference of the coefficient of thermal expansion.

  5. X-ray photoelectron spectroscopy and micro-Raman analysis of conductive RuO2 thin films

    NASA Astrophysics Data System (ADS)

    Bhaskar, S.; Dobal, P. S.; Majumder, S. B.; Katiyar, R. S.

    2001-03-01

    Ruthenium oxide (RuO2) was synthesized in thin film and powder forms using the solution chemistry technique. The oxide electrodes on Si substrates were characterized in terms of their structure, composition, stoichiometry, and conductivity. X-ray lattice parameter calculations and micro-Raman analysis revealed the rutile structure in the material. Both films and powders exhibited an unassigned Raman band at about 477 cm-1 in their Raman spectra. Performing peak frequency calculations for B2g and A1g modes of RuO2 using the rigid-ion model, which ruled out the possibility that this band originated from disorder induced symmetry, allowed silent mode. Based on the x-ray photoelectron spectroscopy (XPS) and temperature dependent Raman studies, this band was assigned to hydrated RuO2. XPS characterizations of our samples revealed minute surface contamination of oxygen and chlorine, probably due to the film preparation and high temperature deposition processes. Films with uniform microstructure, low surface roughness, and good electrical properties meet the requirements for serving as the bottom electrode for the ferroelectric capacitor.

  6. Biochemical and molecular characterization of thyroid tissue by micro-Raman spectroscopy and gene expression analysis

    NASA Astrophysics Data System (ADS)

    Neto, Lázaro P. M.; Martin, Aírton A.; Soto, Claudio A. T.; Santos, André B. O.; Mello, Evandro S.; Pereira, Marina A.; Cernea, Cláudio R.; Brandão, Lenine G.; Canevari, Renata A.

    2016-02-01

    Thyroid carcinomas represent the main endocrine malignancy and their diagnosis may produce inconclusive results. Raman spectroscopy and gene expression analysis have shown excellent results on the differentiation of carcinomas. This study aimed to improve the discrimination between different thyroid pathologies combining of both analyses. A total of 35 thyroid tissues samples including normal tissue (n=10), goiter (n=10), papillary (n=10) and follicular carcinomas (n=5) were analyzed. Confocal Raman spectra was obtain by using a Rivers Diagnostic System, 785 nm laser excitation and CCD detector. The data was processed by the software Labspec5 and Origin 8.5 and analyzed by Minitab® program. The gene expression analysis was performed by qRT-PCR technique for TG, TPO, PDGFB, SERPINA1, LGALS3 and TFF3 genes and statistically analyzed by Mann-Whitney test. The confocal Raman spectroscopy allowed a maximum discrimination of 91.1% between normal and tumor tissues, 84.8% between benign and malignant pathologies and 84.6% among carcinomas analyzed. Significant differences was observed for TG, LGALS3, SERPINA1 and TFF3 genes between benign lesions and carcinomas, and SERPINA1 and TFF3 genes between papillary and follicular carcinomas. Principal component analysis was performed using PC1 and PC2 in the papillary carcinoma samples that showed over gene expression when compared with normal sample, where 90% of discrimination was observed at the Amide 1 (1655 cm-1), and at the tyrosine spectra region (856 cm-1). The discrimination of tissues thyroid carried out by confocal Raman spectroscopy and gene expression analysis indicate that these techniques are promising tools to be used in the diagnosis of thyroid lesions.

  7. NanoSIMS and Micro-Raman Spectroscopy applied to the Analysis of Uranium Oxyfluoride Particles for Nuclear Safeguards

    NASA Astrophysics Data System (ADS)

    Kips, R.; Kristo, M.; Crowhurst, J.; Stefaniak, E.; Hutcheon, I. D.

    2010-12-01

    Environmental swipe sampling is used by safeguards organizations to verify the absence of undeclared nuclear activities. Particulate material collected in environmental swipe samples is typically analyzed for its uranium isotopic composition. At enrichment facilities, these swipe samples often contain UO2F2 particles formed from the hydrolysis of uranium hexafluoride gas. Since UO2F2 particulate material has been found to be unstable with respect to the loss of fluorine (J.A. Carter et al. Task A.200.3 K/NSP-777, 1998) the measurement of the residual amount of fluorine has the potential of placing boundaries on the particle’s age and exposure history. To investigate the decomposition of UO2F2 and its potential applications in nuclear safeguards and nuclear forensics, a suite of micro-analytical tools was applied to a set of lab-synthesized UO2F2 particles. Samples were either stored in an inert atmosphere or exposed to different levels of humidity, temperature and light to identify those environmental conditions that accelerate the decomposition of UO2F2. Given the small size of the particles, secondary ion mass spectrometry with nanometer-scale spatial resolution (NanoSIMS) was used to measure the relative amount of fluorine. The elemental data from the NanoSIMS was complemented with micro-Raman spectroscopy for molecular fingerprinting. These measurements showed that even though the decomposition of UO2F2 generally happens very slowly, subtle differences can be distinguished depending on the environmental conditions to which they were exposed. The exposure to humidity was identified as the main factor accelerating the loss of fluorine in UO2F2 particles. Particles exposed to 30 % relative humidity and higher showed a decrease in the relative amount of fluorine and a shift of the UO22+ symmetric stretching frequency towards lower frequencies. These changes were attributed to an increase in hydration of the UO2F2 particles. This work was performed under the

  8. Study of the reaction products of SF6 and C in the laser heated diamond anvil cell by pair distribution function analysis and micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Rademacher, N.; Bayarjargal, L.; Morgenroth, W.; Bauer, J. D.; Milman, V.; Winkler, B.

    2015-05-01

    The decomposition of SF6 in the presence of glassy carbon was induced in laser heated diamond anvil cells at 10-11 GPa and 2000-2500 K. The reaction products were characterised by synchrotron X-ray diffraction, including high pressure pair distribution function analysis, and micro-Raman spectroscopy combined with atomistic model calculations. The decomposition leads to elemental amorphous helical sulfur and crystalline CF4-III. Two different sulfur phases, namely helical Sμ and crystalline α-S8, were observed after recovering the laser heated samples of different experiments at ambient conditions.

  9. The efficiency of micro-Raman spectroscopy in the analysis of complicated mixtures in modern paints: Munch's and Kupka's paintings under study.

    PubMed

    Košařová, Veronika; Hradil, David; Hradilová, Janka; Čermáková, Zdeňka; Němec, Ivan; Schreiner, Manfred

    2016-03-01

    Twenty one mock-up samples containing inorganic pigments primarily used at the turn of the 19th and 20th century were selected for comparative study and measured by micro-Raman and portable Raman spectrometers. They included pure grounds (chalk-based, earth-based and lithopone-based), grounds covered by resin-based varnish, and different paint layers containing mixtures of white, yellow, orange, red, green, blue and black pigments, usually in combination with white pigments (titanium, zinc and barium whites or chalk). In addition, ten micro-samples obtained from seven paintings of two world-famous modern painters Edvard Munch and František Kupka have been investigated. Infrared reflection spectroscopy (FTIR), portable X-ray fluorescence (XRF) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) were used as supplementary methods. The measurements showed that blue pigments (ultramarine, Prussian blue and azurite), vermilion and ivory black in mixture with whites provided characteristic Raman spectra, while Co-, Cd- and Cr- pigments' bands were suppressed by fluorescence. The best success rate of micro-Raman spectroscopy has been achieved using the 780 nm excitation, however, the sensitivity of this excitation laser in a portable Raman instrument significantly decreased. The analyses of micro-samples of paintings by E. Munch and F. Kupka showed that micro-Raman spectroscopy identified pigments which would remain unidentified if analyzed only by SEM-EDS (zinc yellow, Prussian blue). On the other hand, chromium oxide green and ultramarine were not detected together in a sample due to overlap of their main bands. In those cases, it is always necessary to complement Raman analysis with other analytical methods. PMID:26641284

  10. The efficiency of micro-Raman spectroscopy in the analysis of complicated mixtures in modern paints: Munch's and Kupka's paintings under study

    NASA Astrophysics Data System (ADS)

    Košařová, Veronika; Hradil, David; Hradilová, Janka; Čermáková, Zdeňka; Němec, Ivan; Schreiner, Manfred

    2016-03-01

    Twenty one mock-up samples containing inorganic pigments primarily used at the turn of the 19th and 20th century were selected for comparative study and measured by micro-Raman and portable Raman spectrometers. They included pure grounds (chalk-based, earth-based and lithopone-based), grounds covered by resin-based varnish, and different paint layers containing mixtures of white, yellow, orange, red, green, blue and black pigments, usually in combination with white pigments (titanium, zinc and barium whites or chalk). In addition, ten micro-samples obtained from seven paintings of two world-famous modern painters Edvard Munch and František Kupka have been investigated. Infrared reflection spectroscopy (FTIR), portable X-ray fluorescence (XRF) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) were used as supplementary methods. The measurements showed that blue pigments (ultramarine, Prussian blue and azurite), vermilion and ivory black in mixture with whites provided characteristic Raman spectra, while Co-, Cd- and Cr- pigments' bands were suppressed by fluorescence. The best success rate of micro-Raman spectroscopy has been achieved using the 780 nm excitation, however, the sensitivity of this excitation laser in a portable Raman instrument significantly decreased. The analyses of micro-samples of paintings by E. Munch and F. Kupka showed that micro-Raman spectroscopy identified pigments which would remain unidentified if analyzed only by SEM-EDS (zinc yellow, Prussian blue). On the other hand, chromium oxide green and ultramarine were not detected together in a sample due to overlap of their main bands. In those cases, it is always necessary to complement Raman analysis with other analytical methods.

  11. Ochre-differentiation through micro-Raman and micro-FTIR spectroscopies: application on wall paintings at Meteora and Mount Athos, Greece.

    PubMed

    Bikiaris, D; Daniilia Sister; Sotiropoulou, S; Katsimbiri, O; Pavlidou, E; Moutsatsou, A P; Chryssoulakis, Y

    2000-01-01

    The most widely-used inorganic pigments of Byzantine and post-Byzantine hagiography are earth pigments called ochres such as, red and yellow ochres, limonite, goethite, raw and burnt sienna, caput mortuum and hematite. The present experimental work proposes a technique of differentiation that allows one to distinguish among all the different kinds of iron oxides, thereby providing a better understanding of the painting technique used on portable icons and wall paintings. The ratios between the main spectroscopic peaks, attributable to the major components usually present in ochres, were calculated and compared, one against the another, from the spectra obtained through micro-Raman spectroscopy. Elementary composition is also revealed through a scanning electron microscopy (SEM) analysis. The possibility for detailed study on a particular Byzantine ochre palette can thus be performed based on the small differences in its nature and composition. These differences can first be observed and then measured among all of the natural earth pigments, through microRaman and microFTIR spectroscopies. PMID:10728852

  12. An investigation into the use of micro-Raman spectroscopy for the analysis of car paints and single textile fibres

    NASA Astrophysics Data System (ADS)

    Zięba-Palus, Janina; Wąs-Gubała, Jolanta

    2011-05-01

    Micro-Raman spectroscopy was applied to identification and differentiation between criminalistic traces such as micropaint chips and single fibres. The aim was to determine the degree of discrimination between fibres coloured by defined chemical dye classes and to differentiate between paint samples on the basis of pigment/dye content. Samples of coloured cotton fibres and samples of green car paints were examined. It was found that the majority of the obtained Raman spectra provided information about the main dyes present in the sample. However, in some cases fluorescence of the samples made dye identification impossible. Spectral libraries for examined paint samples and single fibres were created in order to facilitate quick recognition of similar forensic traces using this analytical method.

  13. The analysis of colored acrylic, cotton, and wool textile fibers using micro-Raman spectroscopy. Part 2: comparison with the traditional methods of fiber examination.

    PubMed

    Buzzini, Patrick; Massonnet, Genevieve

    2015-05-01

    In the second part of this survey, the ability of micro-Raman spectroscopy to discriminate 180 fiber samples of blue, black, and red cottons, wools, and acrylics was compared to that gathered with the traditional methods for the examination of textile fibers in a forensic context (including light microscopy methods, UV-vis microspectrophotometry and thin-layer chromatography). This study shows that the Raman technique plays a complementary and useful role to obtain further discriminations after the application of light microscopy methods and UV-vis microspectrophotometry and assure the nondestructive nature of the analytical sequence. These additional discriminations were observed despite the lower discriminating powers of Raman data considered individually, compared to those of light microscopy and UV-vis MSP. This study also confirms that an instrument equipped with several laser lines is necessary for an efficient use as applied to the examination of textile fibers in a forensic setting. PMID:25731068

  14. Improvements in the wallpaper industry during the second half of the 19th century: Micro-Raman spectroscopy analysis of pigmented wallpapers

    NASA Astrophysics Data System (ADS)

    Castro, K.; Vandenabeele, P.; Rodríguez-Laso, M. D.; Moens, L.; Madariaga, J. M.

    2005-08-01

    Scientific studies of the pigments used in the manufacturing process of some pigmented wallpapers are presented in this work. Non-destructive micro-Raman spectroscopy was selected for this purpose, and provides important information about how the 19th century wallpaper industry incorporated new materials in their works and designs. At the same time, analysis can help to date the samples of uncatalogued wallpapers. Chrome yellow, burnt Sienna, Prussian blue, ultramarine blue, red lead, carbon black, calcium carbonate, red iron oxide and a red organic pigment were identified. According to the palette used, as well as to the manufacturing process, the wallpapers in this study can be dated to the second half of the 19th century.

  15. X-ray diffraction and micro-Raman spectroscopy analysis of new nickel hydroxide obtained by electrodialysis

    NASA Astrophysics Data System (ADS)

    Deabate, S.; Fourgeot, F.; Henn, F.

    Industrial nickel hydroxide samples produced by electrodialysis have been characterized both by X-ray diffraction (XRD) and by micro-Raman spectroscopy. A comparison with some commercial products of β-type Ni(OH) 2 is made. Aged in KOH solution, these nickel hydroxides are transformed to the β-Ni(OH) 2 phase and undergo Ostwald ripening, leading to crystallite sizes ranging between 260 and 380 Å with a reduction in defects. The anisotropic broadening of the XRD peaks in the β-Ni(OH) 2 pattern is interpreted in terms of crystalline lattice micro-strains and crystallite size. For the first time, Rietveld refinement has been performed on industrial Ni(OH) 2. The results indicate that the micro-strain effects increase the peak width according to the sequence of families ( hk0)→(00 l)→( h0 l). This study shows that the presence of proton vacancies leads to a lower degree of distortion in the crystalline lattice than does the presence of stacking faults or the adsorption of inorganic species at the border of the crystallites. A very high concentration of point defects inducing strong distortions in the crystal lattice is correlated with the presence of high energy Ni-O bond vibrations in the Raman spectra, with a frequency shift towards unusually high values.

  16. Bone quality around bioactive silica-based coated stainless steel implants: analysis by micro-Raman, XRF and XAS techniques.

    PubMed

    Ballarre, Josefina; Desimone, Paula M; Chorro, Matthieu; Baca, Matías; Orellano, Juan Carlos; Ceré, Silvia M

    2013-11-01

    Surface modification of surgical stainless steel implants by sol gel coatings has been proposed as a tool to generate a surface that besides being protective could also create a "bioactive" interface to generate a natural bonding between the metal surface and the existing bone. The aim of this work is to analyze the quality and bone formation around hybrid bioactive coatings containing glass-ceramic particles, made by sol-gel process on 316L stainless steel used as permanent implant in terms of mineralization, calcium content and bone maturity with micro Raman, X-ray microfluorescence and X-ray absorption techniques. Uncoated implants seem to generate a thin bone layer at the beginning of osseointegration process and then this layer being separated from the surface with time. The hybrid coatings without glass-ceramic particles generate new bone around implants, with high concentration of Ca and P at the implant/tissue interface. This fact seems to be related with the presence of silica nanoparticles in the layer. The addition of bioactive particles promotes and enhances the bone quality with a homogeneous Ca and P content and a low rate of beta carbonate substitution and crystallinity, similar to young and mechanical resistant bone. PMID:24076155

  17. Micro-Raman spectroscopy on oral tissues

    NASA Astrophysics Data System (ADS)

    Zenone, F.; Lepore, M.; Perna, G.; Carmone, P.; Riccio, R.; Gaeta, G. M.; Capozzi, V.

    2006-02-01

    Micro-Raman Spectroscopy (μ-RS) provides a unique tool in medicine for a not invasive and real time analysis of biological tissue for biopsy and "in vivo" investigation. Based on the evaluation of molecular vibration frequencies, the μ-RS is able to detect the main molecular bonds of protein constituents, as the C-H and C-C ones. Changes in frequency or in the relative intensity of the vibration modes revealed by μ-RS can be related to changes of chemical bond and of protein structure induced by pathology. The μ-RS has been performed on samples of oral tissue from informed patients, affected by pemphigus vulgaris (an oral pathology) in an advanced regression state. The biopsies were thin slices (about 1mm thick) with 6mm diameter. The sample was measured through a 170 μm thick cover-glass. The experimental set-up was mainly composed by a He-Ne laser and a monochromator equipped with a Peltier cell and with a grating of 1800 grooves/mm. The laser light was focused on the sample surface by means of a long focal length 50X optical objective. The main protein bonds are clearly detectable in the considered samples and this give important information on the integrity and on the state of tissue components (lipids and proteins), and consequently on the occurrence of pathology. The potential application of this method for in vivo analysis is an invaluable alternative to biopsy and pathological examinations for many medical application as screening diagnostic, therapy progress examination, and surgical support.

  18. Ochre-differentiation through micro-Raman and micro-FTIR spectroscopies: application on wall paintings at Meteora and Mount Athos, Greece

    NASA Astrophysics Data System (ADS)

    Bikiaris, D.; Daniilia, Sister; Sotiropoulou, S.; Katsimbiri, O.; Pavlidou, E.; Moutsatsou, A. P.; Chryssoulakis, Y.

    2000-01-01

    The most widely-used inorganic pigments of Byzantine and post-Byzantine hagiography are earth pigments called ochres such as, red and yellow ochres, limonite, goethite, raw and burnt sienna, caput mortuum and hematite. The present experimental work proposes a technique of differentiation that allows one to distinguish among all the different kinds of iron oxides, thereby providing a better understanding of the painting technique used on portable icons and wall paintings. The ratios between the main spectroscopic peaks, attributable to the major components usually present in ochres, were calculated and compared, one against the another, from the spectra obtained through micro-Raman spectroscopy. Elementary composition is also revealed through a scanning electron microscopy (SEM) analysis. The possibility for detailed study on a particular Byzantine ochre palette can thus be performed based on the small differences in its nature and composition. These differences can first be observed and then measured among all of the natural earth pigments, through μRaman and μFTIR spectroscopies.

  19. Non-invasive and non-destructive micro-XRF and micro-Raman analysis of a decorative wallpaper from the beginning of the 19th century.

    PubMed

    Castro, Kepa; Pérez-Alonso, Maite; Rodríguez-Laso, María Dolores; Etxebarria, Nestor; Madariaga, Juan Manuel

    2007-02-01

    Non-destructive and non-invasive micro-Raman fibre optic and micro-XRF analyses were performed to study a wallpaper from the beginning of the 19th century. The complementarity of these two non-destructive techniques is shown in this work. The analysed artwork is considered one of the most beautiful wallpapers ever manufactured according to the catalogues and books; it is known as Chasse de Compiègne, manufactured by Jacquemart, Paris, in 1812. During the analysis, an unexpected pigment was detected by both analytical techniques: lead-tin yellow type II. This pigment was used until ca. 1750, when other yellow pigments replaced it, thus it is very difficult to find it in paintings afterwards. Together with this pigment, red lead, Prussian blue, brochantite, yellow iron oxide, calcium carbonate, vermilion, carbon black of animal origin (bone black), lead white, and raw and burnt sienna were also determined by combining the analytical information provided by both techniques. A possible degradation of brochantite to antlerite is also discussed. PMID:16838156

  20. In vitro analysis of riboflavin-modified, experimental, two-step etch-and-rinse dentin adhesive: Fourier transform infrared spectroscopy and micro-Raman studies

    PubMed Central

    Daood, Umer; Swee Heng, Chan; Neo Chiew Lian, Jennifer; Fawzy, Amr S

    2015-01-01

    To modify two-step experimental etch-and-rinse dentin adhesive with different concentrations of riboflavin and to study its effect on the bond strength, degree of conversion, along with resin infiltration within the demineralized dentin substrate, an experimental adhesive-system was modified with different concentrations of riboflavin (m/m, 0, 1%, 3%, 5% and 10%). Dentin surfaces were etched with 37% phosphoric acid, bonded with respective adhesives, restored with restorative composite–resin, and sectioned into resin–dentin slabs and beams to be stored for 24 h or 9 months in artificial saliva. Micro-tensile bond testing was performed with scanning electron microscopy to analyse the failure of debonded beams. The degree of conversion was evaluated with Fourier transform infrared spectroscopy (FTIR) at different time points along with micro-Raman spectroscopy analysis. Data was analyzed with one-way and two-way analysis of variance followed by Tukey's for pair-wise comparison. Modification with 1% and 3% riboflavin increased the micro-tensile bond strength compared to the control at 24 h and 9-month storage with no significant differences in degree of conversion (P<0.05). The most predominant failure mode was the mixed fracture among all specimens except 10% riboflavin-modified adhesive specimens where cohesive failure was predominant. Raman analysis revealed that 1% and 3% riboflavin adhesives specimens showed relatively higher resin infiltration. The incorporation of riboflavin in the experimental two-step etch-and-rinse adhesive at 3% (m/m) improved the immediate bond strengths and bond durability after 9-month storage in artificial saliva without adversely affecting the degree of conversion of the adhesive monomers and resin infiltration. PMID:25257880

  1. In vitro analysis of riboflavin-modified, experimental, two-step etch-and-rinse dentin adhesive: Fourier transform infrared spectroscopy and micro-Raman studies.

    PubMed

    Daood, Umer; Swee Heng, Chan; Neo Chiew Lian, Jennifer; Fawzy, Amr S

    2015-06-01

    To modify two-step experimental etch-and-rinse dentin adhesive with different concentrations of riboflavin and to study its effect on the bond strength, degree of conversion, along with resin infiltration within the demineralized dentin substrate, an experimental adhesive-system was modified with different concentrations of riboflavin (m/m, 0, 1%, 3%, 5% and 10%). Dentin surfaces were etched with 37% phosphoric acid, bonded with respective adhesives, restored with restorative composite-resin, and sectioned into resin-dentin slabs and beams to be stored for 24 h or 9 months in artificial saliva. Micro-tensile bond testing was performed with scanning electron microscopy to analyse the failure of debonded beams. The degree of conversion was evaluated with Fourier transform infrared spectroscopy (FTIR) at different time points along with micro-Raman spectroscopy analysis. Data was analyzed with one-way and two-way analysis of variance followed by Tukey's for pair-wise comparison. Modification with 1% and 3% riboflavin increased the micro-tensile bond strength compared to the control at 24 h and 9-month storage with no significant differences in degree of conversion (P<0.05). The most predominant failure mode was the mixed fracture among all specimens except 10% riboflavin-modified adhesive specimens where cohesive failure was predominant. Raman analysis revealed that 1% and 3% riboflavin adhesives specimens showed relatively higher resin infiltration. The incorporation of riboflavin in the experimental two-step etch-and-rinse adhesive at 3% (m/m) improved the immediate bond strengths and bond durability after 9-month storage in artificial saliva without adversely affecting the degree of conversion of the adhesive monomers and resin infiltration. PMID:25257880

  2. X-ray diffraction analysis and scanning micro-Raman spectroscopy of structural irregularities and strains deep inside the multilayered InGaN/GaN heterostructure

    SciTech Connect

    Strelchuk, V. V. Kladko, V. P.; Avramenko, E. A.; Kolomys, O. F.; Safryuk, N. V.; Konakova, R. V.; Yavich, B. S.; Valakh, M. Ya.; Machulin, V. F.; Belyaev, A. E.

    2010-09-15

    High-resolution X-ray diffraction analysis and scanning confocal Raman spectroscopy are used to study the spatial distribution of strains in the In{sub x}Ga{sub 1-x}N/GaN layers and structural quality of these layers in a multilayered light-emitting diode structure produced by metal-organic chemical vapor deposition onto (0001)-oriented sapphire substrates. It is shown that elastic strains almost completely relax at the heterointerface between the thick GaN buffer layer and In{sub x}Ga{sub 1-x}N/GaN buffer superlattice. It is established that the GaN layers in the superlattice are in a stretched state, whereas the alloy layers are in a compressed state. In magnitude, the stretching strains in the GaN layers are lower than the compressive strains in the InGaN layers. It is shown that, as compared to the buffer layers, the layers of the superlattice contain a smaller number of dislocations and the distribution of dislocations is more randomly disordered. In micro-Raman studies on scanning through the thickness of the multilayered structure, direct evidence is obtained for the asymmetric gradient distributions of strains and crystal imperfections of the epitaxial nitride layers along the direction of growth. It is shown that the emission intensity of the In{sub x}Ga{sub 1-x}N quantum well is considerably (more than 30 times) higher than the emission intensity of the GaN barrier layers, suggesting the high efficiency of trapping of charge carriers by the quantum well.

  3. Characterization and differentiation of normal and abnormal semen samples using micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Huang, Zufang; Chen, Xiwen; Chen, Jinhua; Li, Yongzeng; Lei, Jinping; Chen, Rong

    2012-12-01

    Growth in the percentage of male infertility has caused extensive concerns. The fast and reliable method is urgently required for diagnosis of semen samples. In our study, micro-Raman spectroscopy was employed to characterize and differentiate the normal and abnormal semen samples based on the differences of their specific Raman spectra which originated from biochemical components. Our preliminary results demonstrate that micro-Raman spectroscopy combined with multivariate analysis methods has the potential of being used to detect and differentiate semen samples.

  4. The identification of the pigments used to paint statues of Feixiange Cliff in China in late 19th century by micro-Raman spectroscopy and scanning electron microscopy/energy dispersive X-ray analysis

    NASA Astrophysics Data System (ADS)

    Jin, Pu-jun; Huang, Wei; Jianhua-Wang; Zhao, Gang; Wang, Xiao-ling

    2010-11-01

    The application of micro-Raman spectroscopy (μ-RS) and scanning electron microscopy (SEM)/energy dispersive X-ray spectrometer (EDS) to the research of pigments collected from Statues of Feixiange Cliff No. 67 and No. 69 niche of Tang Dynasty in China is reported. Five kinds of pigments were found in the experimental data, including black (carbon), white (gypsum + quartz), blue (lapis lazuli) and green (Paris green + Barium sulphate). After synthesized in 1814, Paris green was reported for a large import as a light and bright green pigment to paint architectures in China from the late 19th century. The analyzed blue pigment demonstrated the similar Raman spectra to the Lâjvardina blue glazed ceramics, which indicated lapis lazuli was an artificial product. This confirmed the painting of Feixiange Cliff in the early Republic of China as the historical record, and also reveals that some pigments were imported from abroad.

  5. Analysis of molecular structure, spectroscopic properties (FT-IR, micro-Raman and UV-vis) and quantum chemical calculations of free and ligand 2-thiopheneglyoxylic acid in metal halides (Cd, Co, Cu, Ni and Zn)

    NASA Astrophysics Data System (ADS)

    Gökce, Halil; Bahçeli, Semiha

    2013-12-01

    In this study, molecular geometries, experimental vibrational wavenumbers, electronic properties and quantum chemical calculations of 2-thiopheneglyoxylic acid molecule, (C6H4O3S), and its metal halides (Cd, Co, Cu, Ni and Zn) which are used as pharmacologic agents have been investigated experimentally by FT-IR, micro-Raman and UV-visible spectroscopies and elemental analysis. Meanwhile the vibrational calculations were verified by DFT/B3LYP method with 6-311++G(d,p) and LANL2DZ basis sets in the ground state, for free TPGA molecule and its metal halide complexes, respectively, for the first time. The calculated fundamental vibrational frequencies for the title compounds are in a good agreement with the experimental data.

  6. Micro-Raman analysis of the pigments on painted pottery figurines from two tombs of the Northern Wei Dynasty in Luoyang

    NASA Astrophysics Data System (ADS)

    Liu, Zhaojun; Han, Yunxia; Han, Ligang; Cheng, Yongjian; Ma, Yiqiang; Fang, Li

    2013-05-01

    The pigments on the painted pottery figurines from two tombs of Northern Wei Dynasty (AD 386-534) in Luoyang were analyzed by Raman microscopy. All the pigments were identified compared with the Raman spectra of standard pigments. The red pigments were identified as haematite, the blue pigment as lapis lazuli, the green pigment as malachite, the black pigment as carbon black and the white pigment as calcite. Similar pigments were used in the two tombs despite the pottery figurines were very different in artistic style. The use of lapis lazuli as blue pigment on Chinese painted pottery figurines was found for the first time. This pigment and the painted pottery figurine of Sogdians are of great archaeological significance because it demonstrated that the trade and cultural exchanges via the Silk Road had extended to Luoyang city in the Northern Wei Dynasty. The result also confirms that micro-Raman spectroscopy is a powerful analytical method for the identification of pigments on ancient artworks.

  7. Micro-Raman analysis of the pigments on painted pottery figurines from two tombs of the Northern Wei Dynasty in Luoyang.

    PubMed

    Liu, Zhaojun; Han, Yunxia; Han, Ligang; Cheng, Yongjian; Ma, Yiqiang; Fang, Li

    2013-05-15

    The pigments on the painted pottery figurines from two tombs of Northern Wei Dynasty (AD 386-534) in Luoyang were analyzed by Raman microscopy. All the pigments were identified compared with the Raman spectra of standard pigments. The red pigments were identified as haematite, the blue pigment as lapis lazuli, the green pigment as malachite, the black pigment as carbon black and the white pigment as calcite. Similar pigments were used in the two tombs despite the pottery figurines were very different in artistic style. The use of lapis lazuli as blue pigment on Chinese painted pottery figurines was found for the first time. This pigment and the painted pottery figurine of Sogdians are of great archaeological significance because it demonstrated that the trade and cultural exchanges via the Silk Road had extended to Luoyang city in the Northern Wei Dynasty. The result also confirms that micro-Raman spectroscopy is a powerful analytical method for the identification of pigments on ancient artworks. PMID:23501716

  8. Micro-Raman spectroscopy Detects Individual Neoplastic and Normal Hematopoietic Cells

    SciTech Connect

    Chan, J W; Taylor, D; Zwerdling, T; Lane, S M; Ihara, K; Huser, T

    2005-01-18

    Current methods for identifying neoplastic cells and discerning them from their normal counterparts are often non-specific, slow, biologically perturbing, or a combination, thereof. Here, we show that single-cell micro-Raman spectroscopy averts these shortcomings and can be used to discriminate between unfixed normal human lymphocytes and transformed Jurkat and Raji lymphocyte cell lines based on their biomolecular Raman signatures. We demonstrate that single-cell Raman spectra provide a highly reproducible biomolecular fingerprint of each cell type. Characteristic peaks, mostly due to different DNA and protein concentrations, allow for discerning normal lymphocytes from transformed lymphocytes with high confidence (p << 0.05). Spectra are also compared and analyzed by principal component analysis (PCA) to demonstrate that normal and transformed cells form distinct clusters that can be defined using just two principal components. The method is shown to have a sensitivity of 98.3% for cancer detection, with 97.2% of the cells being correctly classified as belonging to the normal or transformed type. These results demonstrate the potential application of confocal micro-Raman spectroscopy as a clinical tool for single cell cancer detection based on intrinsic biomolecular signatures, therefore eliminating the need for exogenous fluorescent labeling.

  9. New insight into UO2F2 particulate structure by micro-Raman spectroscopy

    DOE PAGESBeta

    Stefaniak, Elzbieta A.; Darchuk, Larysa; Sapundjiev, Danislav; Kips, Ruth E.; Aregbe, Yetunde; Grieken, Rene Van

    2013-02-19

    Uranyl fluoride particles produced via hydrolysis of uranium hexafluoride have been deposited on different substrates: polished graphite disks, silver foil, stainless steel and gold-coated silicon wafer, and measured with micro-Raman spectroscopy (MRS). All three metallic substrates enhanced the Raman signal delivered by UO2F2 in comparison to graphite. The fundamental stretching of the U–O band appeared at 867 cm–1 in case of the graphite substrate, while in case of the others it was shifted to lower frequencies (down to 839 cm–1). All applied metallic substrates showed the expected effect of Raman signal enhancement; however the gold layer appeared to be mostmore » effective. Lastly, application of new substrates provides more information on the molecular structure of uranyl fluoride precipitation, which is interesting for nuclear safeguards and nuclear environmental analysis.« less

  10. New insight into UO2F2 particulate structure by micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Stefaniak, Elżbieta A.; Darchuk, Larysa; Sapundjiev, Danislav; Kips, Ruth; Aregbe, Yetunde; Van Grieken, René

    2013-05-01

    Uranyl fluoride particles produced via hydrolysis of uranium hexafluoride have been deposited on different substrates: polished graphite disks, silver foil, stainless steel and gold-coated silicon wafer, and measured with micro-Raman spectroscopy (MRS). All three metallic substrates enhanced the Raman signal delivered by UO2F2 in comparison to graphite. The fundamental stretching of the U-O band appeared at 867 cm-1 in case of the graphite substrate, while in case of the others it was shifted to lower frequencies (down to 839 cm-1). All applied metallic substrates showed the expected effect of Raman signal enhancement; however the gold layer appeared to be most effective. Application of new substrates provides more information on the molecular structure of uranyl fluoride precipitation, which is interesting for nuclear safeguards and nuclear environmental analysis.

  11. Study of molecule variations in renal tumor based on confocal micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhuang, Zhengfei; Li, Ning; Guo, Zhouyi; Zhu, Meifang; Xiong, Ke; Chen, Sijin

    2013-03-01

    Confocal micro-Raman spectroscopy-a valuable analytical tool in biological and medical field of research-allows probing molecular vibrations of samples without external labels or extensive preparation. We employ confocal micro-Raman spectroscopy to characterize renal tumors and normal tissue. Results show that Raman peaks of the renal tumor at 788 and 1087 cm-1, which belong to νs and νas stretching, respectively, have an obvious increase. At the same time, the ratio of I855/I831 in renal tumor tissue is 1.39±0.08, while that in normal renal tissue is 2.44±0.05 (p<0.01). This means that more tyrosine conformation transform from "buried" to "exposed" in the presence of cancer. Principal component analysis is used to classify the Raman spectra of renal tumor tissue and normal tissue.

  12. Micro-Raman spectroscopy for meat type detection

    NASA Astrophysics Data System (ADS)

    De Biasio, M.; Stampfer, P.; Leitner, R.; Huck, C. W.; Wiedemair, V.; Balthasar, D.

    2015-06-01

    The recent horse meat scandal in Europe increased the demand for optical sensors that can identify meat type. Micro-Raman spectroscopy is a promising technique for the discrimination of meat types. Here, we present micro-Raman measurements of chicken, pork, turkey, mutton, beef and horse meat test samples. The data was analyzed with different combinations of data normalization and classification approaches. Our results show that Raman spectroscopy can discriminate between different meat types. Red and white meat are easily discriminated, however a sophisticated chemometric model is required to discriminate species within these groups.

  13. New insight into UO2F2 particulate structure by micro-Raman spectroscopy

    SciTech Connect

    Stefaniak, Elzbieta A.; Darchuk, Larysa; Sapundjiev, Danislav; Kips, Ruth E.; Aregbe, Yetunde; Grieken, Rene Van

    2013-02-19

    Uranyl fluoride particles produced via hydrolysis of uranium hexafluoride have been deposited on different substrates: polished graphite disks, silver foil, stainless steel and gold-coated silicon wafer, and measured with micro-Raman spectroscopy (MRS). All three metallic substrates enhanced the Raman signal delivered by UO2F2 in comparison to graphite. The fundamental stretching of the U–O band appeared at 867 cm–1 in case of the graphite substrate, while in case of the others it was shifted to lower frequencies (down to 839 cm–1). All applied metallic substrates showed the expected effect of Raman signal enhancement; however the gold layer appeared to be most effective. Lastly, application of new substrates provides more information on the molecular structure of uranyl fluoride precipitation, which is interesting for nuclear safeguards and nuclear environmental analysis.

  14. Mineralogical Mapping of the Banded Iron Formations using Fourier Transform Infra-Red (FTIR) Spectroscopy and micro-Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    McKeeby, B. E.; Schoonen, M. A.; Glotch, T. D.; Ohmoto, H.

    2013-12-01

    Banded Iron Formations (BIFs) consist of thin alternating layers of iron-poor silica and iron-bearing phylosilicates, iron oxides, and carbonates and/or sulfides. BIFs are common in the Precambrian. Although BIFs have been the subject of numerous studies, the mechanism and environments of formation remains poorly understood. It has been hotly debated whether BIFs formed by microbes in Fe2+-rich oceans under a reducing atmosphere, or by reactions between locally discharged submarine hydrothermal fluids and O2-rich deep ocean water. The debates have continued mostly because of the lack of detailed studies on the paragenesis of minerals in BIFs to determine which minerals are primary precipitates, and which are diagenetic and metamorphic products. The purpose of this study is to explore the applications of FTIR spectroscopy and micro-Raman spectroscopy in micro-scale paragenetic studies of BIF samples. FTIR and Raman are vibrational spectroscopy techniques that provide insight into the chemical bonding within a compound. With these techniques it is possible to resolve the iron oxide, carbonate, and clay mineralogy within BIFs, which is difficult with techniques that rely on elemental analysis, such as TEM-EDAX. Samples used in this study are thin sections of the 2.7 Ga BIFs from Temagami in the Abitibi green stone belt, Ontario, Canada. FTIR analyses were conducted using a Nicolet iN10MX Micro-Imaging FTIR Spectrometer. This instrument is capable of collecting hyperspectral infrared images with a pixel size of 25 microns covering the range from 7000 to 715 cm-1. In addition, we collected point spectra measuring 50X50 microns over a spectral range from 4000 to 400 cm-1. These point spectra were used to distinguish among different iron minerals in the thin sections. Using the hyperspectral data, we created composite false color Images to show mineral variation across the samples. The spectra were modeled using a digital spectral library. After modeling and examination

  15. Micro Raman, Mossbauer and magnetic studies of manganese substituted zinc ferrite nanoparticles: Role of Mn

    NASA Astrophysics Data System (ADS)

    Thota, Suneetha; Kashyap, Subhash C.; Sharma, Shiv K.; Reddy, V. R.

    2016-04-01

    A series of Mn-Zn Ferrite nanoparticles (<15 nm) with formula MnxZn1-xFe2O4 (where x=0.00, 0.35, 0.50, 0.65) were successfully prepared by citrate-gel method at low temperature (400 °C). X-ray diffraction analysis confirmed the formation of single cubic spinel phase in these nanoparticles. The FESEM and TEM micrographs revealed the nanoparticles to be nearly spherical in shape and of fairly uniform size. The fractions of Mn2+, Zn2+ and Fe3+ cations occupying tetrahedral sites along with Fe occupying octahedral sites within the unit cell of different ferrite samples are estimated by room temperature micro-Raman spectroscopy. Low temperature Mossbauer measurement on Mn0.5Zn0.5Fe2O4 has reconfirmed the mixed spinel phase of these nanoparticles. Room temperature magnetization studies (PPMS) of Mn substituted samples showed superparamagnetic behavior. Manganese substitution for Zn in the ferrite caused the magnetization to increase from 04 to18 emu/g and Lande's g factor (estimated from ferromagnetic resonance measurement) from 2.02 to 2.12 when x was increased up to 0.50. The FMR has shown that higher Mn cationic substitution leads to increase in dipolar interaction and decrease in super exchange interaction. Thermomagnetic (M-T) and magnetization (M-H) measurements have shown that the increase in Mn concentration (up to x=0.50) enhances the spin ordering temperature up to 150 K (blocking temperature). Magnetocrystalline anisotropy in the nanoparticles was established by Mossbauer, ferromagnetic resonance and thermomagnetic measurements. The optimized substitution of manganese for zinc improves the magnetic properties and makes these nanoparticles a potential candidate for their applications in microwave region and biomedical field.

  16. Multi-fiber strains measured by micro-Raman spectroscopy: Principles and experiments

    NASA Astrophysics Data System (ADS)

    Lei, Zhenkun; Wang, Yunfeng; Qin, Fuyong; Qiu, Wei; Bai, Ruixiang; Chen, Xiaogang

    2016-02-01

    Based on widely used axial strain measurement method of Kevlar single fiber, an original theoretical model and measurement principle of application of micro-Raman spectroscopy to multi-fiber strains in a fiber bundle were established. The relationship between the nominal Raman shift of fiber bundle and the multi-fiber strains was deduced. The proposed principle for multi-fiber strains measurement is consistent with two special cases: single fiber deformation and multi-fiber deformation under equal strain. It is found experimentally that the distribution of Raman scattering intensity of a Kevlar 49 fiber as a function of distance between a fiber and the laser spot center follows a Gaussian function. Combining the Raman-shift/strain relationship of the Kevlar 49 single fiber and the uniaxial tension measured by micro-Raman spectroscopy, the Raman shift as a function of strain was obtained. Then the Raman peak at 1610 cm-1 for the Kevlar 49 fiber was fitted to a Lorentzian function and the FWHM showed a quadratic increase with the fiber strain. Finally, a dual-fiber tensile experiment was performed to verify the adequacy of the Raman technique for the measurement of multi-fiber strains.

  17. Polarized micro-Raman spectroscopy study of pentacene thin films

    NASA Astrophysics Data System (ADS)

    Stenger, Ingrid; Frigout, Alexandre; Tondelier, Denis; Geffroy, Bernard; Ossikovski, Razvigor; Bonnassieux, Yvan

    2009-03-01

    We report on polarized micro-Raman spectroscopy study of two pentacene thin films exhibiting different microstructures: a well-ordered sample and a more disordered one. We have investigated the frequency range of the intramolecular C-H bending modes in the plane of the pentacene molecule and proposed an interpretation of the Raman spectra. The use of symmetry properties of the two intramolecular (uncoupled) modes allowed us to unambiguously identify it among the five main contributions observed in this spectral range. The three other modes were assumed to be resulting from molecular coupling effect owing to their different behavior upon the samples microstructure.

  18. [Calibration Procedure of Laser Confocal Micro-Raman Spectrometer].

    PubMed

    Zhao, Ying-chun; Ren, Ling-ling; Wei, Wei-sheng; Yao, Ya-xuan

    2015-09-01

    As a common spectral characterization technique, Raman spectroscopy is widely used and has a specified calibration procedure. Based on laser confocal micro-Raman spectrometer, in this paper, we briefly introduced the principle, configuration and main components of Raman spectrometer. In addition, the calibration procedures were also presented, with an emphasis on the calibration of spectrometer (spectrograph) and that of excitation laser wavelength. On the basis of conventional calibration method, a novel and more accurate method was proposed to obtain the actual excitation wavelength, that is, calibration at the point of Raman shift Δν=0. Using this novel calibration method of excitation wavelength, Raman frequency shift values of sulfur were measured, and compared with the standard values from American Society Testing and Materials (ASTM). As a result, the measured values after calibration were consistent with those ASTM values, which indicated that the calibration method is accurate. Thus, a more reasonable calibration procedure of the laser confocal micro-Raman spectrometer was provided. PMID:26669164

  19. Micro-Raman spectroscopy a powerful technique to identify crocidolite and erionite fibers in tissue sections

    NASA Astrophysics Data System (ADS)

    Rinaudo, C.; Croce, A.; Allegrina, M.; Baris, I. Y.; Dogan, A.; Powers, A.; Rivera, Z.; Bertino, P.; Yang, H.; Gaudino, G.; Carbone, M.

    2013-05-01

    Exposure to mineral fibers such asbestos and erionite is widely associated with the development of lung cancer and pleural malignant mesothelioma (MM). Pedigree and mineralogical studies indicated that genetics may influence mineral fiber carcinogenesis. Although dimensions strongly impact on the fiber carcinogenic potential, also the chemical composition and the fiber is relevant. By using micro-Raman spectroscopy we show here persistence and identification of different mineral phases, directly on histopathological specimens of mice and humans. Fibers of crocidolite asbestos and erionite of different geographic areas (Oregon, US and Cappadocia, Turkey) were injected in mice intra peritoneum. MM developed in 10/15 asbestos-treated mice after 5 months, and in 8-10/15 erionite-treated mice after 14 months. The persistence of the injected fibers was investigated in pancreas, liver, spleen and in the peritoneal tissue. The chemical identification of the different phases occurred in the peritoneal cavity or at the organ borders, while only rarely fibers were localized in the parenchyma. Raman patterns allow easily to recognize crocidolite and erionite fibers. Microscopic analysis revealed that crocidolite fibers were frequently coated by ferruginous material ("asbestos bodies"), whereas erionite fibers were always free from coatings. We also analyzed by micro-Raman spectroscopy lung tissues, both from MM patients of the Cappadocia, where a MM epidemic developed because of environmental exposure to erionite, and from Italian MM patients with occupational exposure to asbestos. Our findings demonstrate that micro-Raman spectroscopy is technique able to identify mineral phases directly on histopathology specimens, as routine tissue sections prepared for diagnostic purpose. REFERENCES A.U. Dogan, M. Dogan. Environ. Geochem. Health 2008, 30(4), 355. M. Carbone, S. Emri, A.U. Dogan, I. Steele, M. Tuncer, HI. Pass, et al. Nat. Rev. Cancer. 2007, 7 (2),147. M. Carbone, Y

  20. Determination of chemical composition of individual airborne particles by SEM/EDX and micro-Raman spectrometry: A review

    NASA Astrophysics Data System (ADS)

    Stefaniak, E. A.; Buczynska, A.; Novakovic, V.; Kuduk, R.; Van Grieken, R.

    2009-04-01

    The strategies for sampling and analysis by SEM/EDX and micro-Raman spectrometry for individual airborne particles analysis as applied at the University of Antwerp (Belgium) by the MITAC group have been reviewed. Microbeam techniques provide detailed information concerning the origin, formation, transport, reactivity, transformation reactions and environmental impact of particulate matter. Moreover, some particles of certain chemical properties have been recognized as a threat for human health and cultural heritage objects. However, the small sizes of particles result in specific problems with respect to single particle analysis. Development of equipment and software for improvement of analysis and quantification are reported.

  1. Visible micro-Raman spectroscopy of single human mammary epithelial cells exposed to x-ray radiation

    NASA Astrophysics Data System (ADS)

    Delfino, Ines; Perna, Giuseppe; Lasalvia, Maria; Capozzi, Vito; Manti, Lorenzo; Camerlingo, Carlo; Lepore, Maria

    2015-03-01

    A micro-Raman spectroscopy investigation has been performed in vitro on single human mammary epithelial cells after irradiation by graded x-ray doses. The analysis by principal component analysis (PCA) and interval-PCA (i-PCA) methods has allowed us to point out the small differences in the Raman spectra induced by irradiation. This experimental approach has enabled us to delineate radiation-induced changes in protein, nucleic acid, lipid, and carbohydrate content. In particular, the dose dependence of PCA and i-PCA components has been analyzed. Our results have confirmed that micro-Raman spectroscopy coupled to properly chosen data analysis methods is a very sensitive technique to detect early molecular changes at the single-cell level following exposure to ionizing radiation. This would help in developing innovative approaches to monitor radiation cancer radiotherapy outcome so as to reduce the overall radiation dose and minimize damage to the surrounding healthy cells, both aspects being of great importance in the field of radiation therapy.

  2. A micro-Raman spectroscopic investigation of leukemic U-937 cells in aged cultures

    NASA Astrophysics Data System (ADS)

    Fazio, Enza; Trusso, Sebastiano; Franco, Domenico; Nicolò, Marco Sebastiano; Allegra, Alessandro; Neri, Fortunato; Musolino, Caterina; Guglielmino, Salvatore P. P.

    2016-04-01

    Recently it has been shown that micro-Raman spectroscopy combined with multivariate analysis is able to discriminate among different types of tissues and tumoral cells by the detection of significant alterations and/or reorganizations of complex biological molecules, such as nucleic acids, lipids and proteins. Moreover, its use, being in principle a non-invasive technique, appears an interesting clinical tool for the evaluation of the therapeutical effects and of the disease progression. In this work we analyzed molecular changes in aged cultures of leukemia model U937 cells with respect to fresh cultures of the same cell line. In fact, structural variations of individual neoplastic cells on aging may lead to a heterogeneous data set, therefore falsifying confidence intervals, increasing error levels of analysis and consequently limiting the use of Raman spectroscopy analysis. We found that the observed morphological changes of U937 cells corresponded to well defined modifications of the Raman contributions in selected spectral regions, where markers of specific functional groups, useful to characterize the cell state, are present. A detailed subcellular analysis showed a change in cellular organization as a function of time, and correlated to a significant increase of apoptosis levels. Besides the aforementioned study, Raman spectra were used as input for principal component analysis (PCA) in order to detect and classify spectral changes among U937 cells.

  3. Micro-Raman spectroscopic investigation of external wall paintings from St. Dumitru's Church, Suceava, Romania.

    PubMed

    Hernanz, A; Bratu, I; Marutoiu, O F; Marutoiu, C; Gavira-Vallejo, J M; Edwards, H G M

    2008-09-01

    The external sixteenth century wall paintings of St. Dumitru's Church in Suceava (Romania) are suffering visually from deterioration. Fragments of these paintings spallated from the external wall have been studied by micro-Raman microscopy in order to elucidate possible causes of this process. Calcite and alpha-quartz are the components of the substratum indicating that the artists used the Roman fresco technique comprising a limewash putty. No organic binders have been detected in the substrate or pigment application. Amorphous carbon and goethite, alpha-FeOOH, have been identified in areas containing residues of grey and yellow pigments, respectively. Small amounts of gypsum have been detected in the grey areas which we attribute to special attention being given to surface preparation and pigment application in these areas. An abundance of sodium nitrate, nitratine, microcrystals have been observed on the surfaces of many fragments which suggests that a biodeterioration process originating from guano deposits could have been operating in these frescoes. PMID:18649075

  4. Oral pathology diagnosis by means of micro-Raman spectroscopy on biopsies and blood serum

    NASA Astrophysics Data System (ADS)

    Zenone, F.; Lepore, M.; Perna, G.; Carmone, P.; Delfino, I.; Gaeta, G. M.; Capozzi, V.

    2007-02-01

    Pemphigus vulgaris is a chronic, autoimmune, blistering disease of the skin and mucous membranes with a potentially fatal outcome. In this case micro-Raman spectroscopy (μ-RS) can provide a powerful tool for a not invasive analysis of biological tissue for biopsy and in vivo investigation. Based on the evaluation of molecular vibration frequencies, the μ-RS is able to detect the main molecular bonds of protein constituents, as the C-H and C-C ones. Changes in frequency or in the relative intensity of the vibration modes revealed by μ-RS can be related to changes of chemical bond and of protein structure induced by pathology. Quantitative information on the intensity variation of specific Raman lines can be extracted by Partial Least Square (PLS) analysis. μ-RS was performed on some samples of oral tissue and blood serum from informed patients affected by pemphigus vulgaris (an oral pathology) at different pathology stages. The spectra were measured by means of a Raman confocal microspectrometer apparatus using the 633 nm line of a He- Ne laser source. The main protein bonds are clearly detectable in the considered samples giving important information on the integrity and on the state of tissue and blood serum components (lipids and proteins), and consequently on the occurrence of pathology.

  5. Structural properties of GaNAs nanowires probed by micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Filippov, S.; Ishikawa, F.; Chen, W. M.; Buyanova, I. A.

    2016-02-01

    GaNAs-based nanowires (NWs) form a novel material system of potential importance for applications in advanced optoelectronic and photonic devices, thanks to the advantages provided by band-structure engineering, one-dimensional architecture and the possibility to combine them with mainstream silicon technology. In this work we utilize the micro-Raman scattering technique to systematically study the structural properties of such GaAs/GaNAs core/shell NW structures grown by molecular beam epitaxy on a Si substrate. It is shown that the employed one-dimensional architecture allows the fabrication of a GaNAs shell with a low degree of alloy disorder and weak residual strain, at least within the studied range of nitrogen (N) compositions [N] < 0.6%. Raman scattering by the GaAs-like and GaN-like phonons is found to be enhanced when the excitation energy approaches the E+ transition energy. Since this effect is found to be more pronounced for the GaN-like phonons, the involved intermediate states are concluded to be localized in proximity to N impurities, i.e. they likely represent N-related cluster states located in proximity to E+.

  6. Accelerated Detection of Viral Particles by Combining AC Electric Field Effects and Micro-Raman Spectroscopy

    PubMed Central

    Tomkins, Matthew Robert; Liao, David Shiqi; Docoslis, Aristides

    2015-01-01

    A detection method that combines electric field-assisted virus capture on antibody-decorated surfaces with the “fingerprinting” capabilities of micro-Raman spectroscopy is demonstrated for the case of M13 virus in water. The proof-of-principle surface mapping of model bioparticles (protein coated polystyrene spheres) captured by an AC electric field between planar microelectrodes is presented with a methodology for analyzing the resulting spectra by comparing relative peak intensities. The same principle is applied to dielectrophoretically captured M13 phage particles whose presence is indirectly confirmed with micro-Raman spectroscopy using NeutrAvidin-Cy3 as a labeling molecule. It is concluded that the combination of electrokinetically driven virus sampling and micro-Raman based signal transduction provides a promising approach for time-efficient and in situ detection of viruses. PMID:25580902

  7. Wavelet data processing of micro-Raman spectra of biological samples

    NASA Astrophysics Data System (ADS)

    Camerlingo, C.; Zenone, F.; Gaeta, G. M.; Riccio, R.; Lepore, M.

    2006-02-01

    A wavelet multi-component decomposition algorithm is proposed for processing data from micro-Raman spectroscopy (μ-RS) of biological tissue. The μ-RS has been recently recognized as a promising tool for the biopsy test and in vivo diagnosis of degenerative human tissue pathologies, due to the high chemical and structural information contents of this spectroscopic technique. However, measurements of biological tissues are usually hampered by typically low-level signals and by the presence of noise and background components caused by light diffusion or fluorescence processes. In order to overcome these problems, a numerical method based on discrete wavelet transform is used for the analysis of data from μ-RS measurements performed in vitro on animal (pig and chicken) tissue samples and, in a preliminary form, on human skin and oral tissue biopsy from normal subjects. Visible light μ-RS was performed using a He-Ne laser and a monochromator with a liquid nitrogen cooled charge coupled device equipped with a grating of 1800 grooves mm-1. The validity of the proposed data procedure has been tested on the well-characterized Raman spectra of reference acetylsalicylic acid samples.

  8. Investigation on Clarified Fruit Juice Composition by Using Visible Light Micro-Raman Spectroscopy

    PubMed Central

    Camerlingo, Carlo; Zenone, Flora; Delfino, Ines; Diano, Nadia; Mita, Damiano Gustavo; Lepore, Maria

    2007-01-01

    Liquid samples of clarified apple and apricot juices at different production stages were investigated using visible light micro-Raman spectroscopy in order to assess its potential in monitoring fruit juice production. As is well-known, pectin plays a strategic role in the production of clarified juice and the possibility of using Raman for its detection during production was therefore evaluated. The data analysis has enabled the clear identification of pectin. In particular, Raman spectra of apple juice samples from washed and crushed fruits revealed a peak at 845 cm-1 (typical of pectin) which disappears in the Raman spectra of depectinised samples. The fructose content was also revealed by the presence of four peaks at 823 cm-1, 872 cm-1, 918 cm-1 and 975 cm-1. In the case of apricot juice, several Raman fingerprints of β-carotene at 1008, 1159 and 1520 cm-1 were also highlighted. Present results resulted interesting for the exclusive use of optical methods for the quantitative determination of the above-mentioned substances in place of the biochemical assays generally used for this purpose, which are time consuming and require different chemical reagents for each of them.

  9. [Confocal micro Raman spectroscopy for the identification of the binder used in Chinese painted cultural relics].

    PubMed

    Huang, Jian-hua; Yang, Lu; Yu, Shan-shan

    2011-03-01

    For identification of the binder used in Chinese painted cultural relics, the micro-Raman spectroscopy was used to test the pig skin glue, pig bone glue, egg yolk, egg white and peach glue which were commonly used as binder in the relies. The difference between proteinaceous binder and peach glue are distinctly. According to the analysis of their Raman spectrum, the vibrations located at 1463 and 1088 cm(-1) are the features of peach glue. The four kinds of proteinaceous binder also have respective features of their own, although there are many common features in their Raman spectrum. The vibration of 1737 cm(-1) is the feature of pig skin glue, and tie pig bone glue has the feature of vibration located in 962 cm(-1). The vibrations of 1535-1555 and 759 cm(-1) are the features of egg, including egg yolk and egg white. And the egg yolk has another vibration located at 1749 cm(-1) which is different from egg white. It was concluded that the binder can be identified based on the features of Raman spectrum. PMID:21595219

  10. Characterization of bubble core and cloudiness in Yb3+:Sr5(PO4)3F crystals using Micro-Raman spectroscopy

    SciTech Connect

    Cui, Y; Roy, U N; Bai, L; Burger, A; Qiu, S R; Schaffers, K

    2006-11-15

    Ytterbium doped strontium fluoroapatite Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F (Yb: S-FAP) crystals have been used in High Average Power Laser systems as gain medium. Growth induced defects associated with the crystal often affect their performance. In order to improve the crystal quality and its optical applications, it is imperative to understand the nature of these defects. In this study, we utilize Micro-Raman spectroscopy to characterize two common growth-induced defects: bubble core and cloudiness. We find the bubble core consist of voids and microcrystals of Yb: S-FAP. These microcrystals have very different orientation from that of the pure crystal outside the bubble core. In contrast to a previous report, neither Sr{sub 3}(PO{sub 4}){sub 2} nor Yb{sub 2}O{sub 3} are observed in the bubble core regions. On the other hand, the cloudy regions are made up of the host materials blended with a structural deformation along with impurities which include CaCO{sub 3}, YbPO{sub 4}, SrHPO{sub 4} and Sr{sub 2}P{sub 2}O{sub 7}. The impurities are randomly distributed in the cloudy regions. This analysis is necessary for understanding and eliminating these growth defects in Yb:S-FAP crystals.

  11. Detection of Receptor-Induced Glycoprotein Conformational Changes on Enveloped Virions by Using Confocal Micro-Raman Spectroscopy

    PubMed Central

    Lu, Xiaonan; Liu, Qian; Benavides-Montano, Javier A.; Nicola, Anthony V.; Aston, D. Eric; Rasco, Barbara A.

    2013-01-01

    Conformational changes in the glycoproteins of enveloped viruses are critical for membrane fusion, which enables viral entry into cells and the pathological cell-cell fusion (syncytia) associated with some viral infections. However, technological capabilities for identifying viral glycoproteins and their conformational changes on actual enveloped virus surfaces are generally scarce, challenging, and time-consuming. Our model, Nipah virus (NiV), is a syncytium-forming biosafety level 4 pathogen with a high mortality rate (40 to 75%) in humans. Once the NiV attachment glycoprotein (G) (NiV-G) binds the cell receptor ephrinB2 or -B3, G triggers conformational changes in the fusion glycoprotein (F) that result in membrane fusion and viral entry. We demonstrate that confocal micro-Raman spectroscopy can, within minutes, simultaneously identify specific G and F glycoprotein signals and receptor-induced conformational changes in NiV-F on NiV virus-like particles (VLPs). First, we identified reproducible G- and F-specific Raman spectral features on NiV VLPs containing M (assembly matrix protein), G, and/or F or on NiV/vesicular stomatitis virus (VSV) pseudotyped virions via second-derivative transformations and principal component analysis (PCA). Statistical analyses validated our PCA models. Dynamic temperature-induced conformational changes in F and G or receptor-induced target membrane-dependent conformational changes in F were monitored in NiV pseudovirions in situ in real time by confocal micro-Raman spectroscopy. Advantageously, Raman spectroscopy can identify specific protein signals in relatively impure samples. Thus, this proof-of-principle technological development has implications for the rapid identification and biostability characterization of viruses in medical, veterinary, and food samples and for the analysis of virion glycoprotein conformational changes in situ during viral entry. PMID:23283947

  12. A novel micro-Raman technique to detect and characterize 4H-SiC stacking faults

    SciTech Connect

    Piluso, N. Camarda, M.; La Via, F.

    2014-10-28

    A novel Micro-Raman technique was designed and used to detect extended defects in 4H-SiC homoepitaxy. The technique uses above band-gap high-power laser densities to induce a local increase of free carriers in undoped epitaxies (n < 10{sup 16} at/cm{sup −3}), creating an electronic plasma that couples with the longitudinal optical (LO) Raman mode. The Raman shift of the LO phonon-plasmon-coupled mode (LOPC) increases as the free carrier density increases. Crystallographic defects lead to scattering or recombination of the free carriers which results in a loss of coupling with the LOPC, and in a reduction of the Raman shift. Given that the LO phonon-plasmon coupling is obtained thanks to the free carriers generated by the high injection level induced by the laser, we named this technique induced-LOPC (i-LOPC). This technique allows the simultaneous determination of both the carrier lifetime and carrier mobility. Taking advantage of the modifications on the carrier lifetime induced by extended defects, we were able to determine the spatial morphology of stacking faults; the obtained morphologies were found to be in excellent agreement with those provided by standard photoluminescence techniques. The results show that the detection of defects via i-LOPC spectroscopy is totally independent from the stacking fault photoluminescence signals that cover a large energy range up to 0.7 eV, thus allowing for a single-scan simultaneous determination of any kind of stacking fault. Combining the i-LOPC method with the analysis of the transverse optical mode, the micro-Raman characterization can determine the most important properties of unintentionally doped film, including the stress status of the wafer, lattice impurities (point defects, polytype inclusions) and a detailed analysis of crystallographic defects, with a high spectral and spatial resolution.

  13. Residual stress measurements in polycrystalline graphite with micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Krishna, Ram; Jones, Abbie N.; Edge, Ruth; Marsden, Barry J.

    2015-06-01

    Micro-Raman microscopy technique is applied to evaluate unevenly distributed residual stresses in the various constituents of polygranular reactor grades graphite. The wavenumber based Raman shift (cm-1) corresponds to the local residual stress and measurements of stress dependent first order Raman spectra in graphite have enabled localized residual stress values to be determined. The bulk polygranular graphite of reactor grades - Gilsocarbon, NBG-18 and PGA - are examined to illustrate the residual stress variations in their constituents. Binder phase and filler particles have shown to be under compressive and tensile stresses, respectively. Among the studied graphite grades, the binder phase in Gilsocarbon has the highest residual stress and NBG-18 has the lowest value. Filler particles in Gilsocarbon have the highest residual stress and PGA showed the lowest, this is most likely due to the morphology of the coke particles used in the manufacturing and applied processing techniques for fabrications. Stresses have also been evaluated along the peripheral of pores and at the tips of the cracks. Cracks in filler and binder phases have shown mixed behaviour, compressive as well as tensile, whereas pores in binder and filler particles have shown compressive behaviour. The stresses in these graphitic constituents are of the order of MPa. Non-destructive analyses presented in this study make the current state-of-the-art technique a powerful method for the study of stress variations near the graphite surface and are expected to increase its use further in property determination analysis of low to highly fluence irradiated graphite samples from the material test reactors.

  14. All-Optical Blister Test of Suspended Graphene Using Micro-Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Metten, Dominik; Federspiel, François; Romeo, Michelangelo; Berciaud, Stéphane

    2014-11-01

    We report a comprehensive micro-Raman study of a pressurized suspended graphene membrane that hermetically seals a circular pit, etched in a Si /SiO2 substrate. Placing the sample under a uniform pressure load results in bulging of the graphene membrane and subsequent softening of the main Raman features, due to tensile strain. In such a microcavity, the intensity of the Raman features depends very sensitively on the distance between the graphene membrane and the Si substrate, which acts as the bottom mirror of the cavity. Thus, a spatially resolved analysis of the intensity of the G - and 2 D -mode features as a function of the pressure load permits a direct reconstruction of the blister profile. An average strain is then deduced at each pressure load, and Grüneisen parameters of 1.8 ±0.2 and 2.4 ±0.2 are determined for the Raman G and 2 D modes, respectively. In addition, the measured blister height is proportional to the cubic root of the pressure load, as predicted theoretically. The validation of this scaling provides a direct and accurate determination of the Young's modulus of graphene with a purely optical, hence contactless and minimally invasive, approach. We find a Young's modulus of (1.05 ±0.10 ) TPa for monolayer graphene, in a perfect match with previous nanoindentation measurements. This all-optical methodology opens avenues for pressure sensing using graphene and could readily be adapted to other emerging two-dimensional materials and to nanoresonators.

  15. Microscopy and microRaman study of periodically poled domains in deeply thinned lithium niobate wafers

    NASA Astrophysics Data System (ADS)

    Bullen, P. S.; Huang, H.-C.; Yang, H.; Dadap, J. I.; Kymissis, I.; Osgood, R. M.

    2016-07-01

    The domain structure of poled deeply thinned lithium niobate is investigated as a function of sample thickness. Free-standing samples of thickness from 25 to 500 μm are prepared by a multiple-cycle polish and annealing procedure and then periodically poled. Using these samples and employing micro-Raman scattering and scanning electron, atomic force, and optical microscopy together, the domain broadening and poling voltage are found to vary in a regular and significant manner. The poled domains show a reduction in width spreading of 38% as the sample thickness is reduced from 500 to 25 μm. Micro-Raman probe measurements verify the quality and the uniformity of the poled domains and provide insight into their thickness-dependent poling contrast.

  16. Characterizing the Biological and Geochemical Architecture of Hydrothermally Derived Sedimentary Deposits: Coupling Micro Raman Spectroscopy with Noble Gas Spectrometry

    NASA Astrophysics Data System (ADS)

    Bower, D. M.; Conrad, P. G.; Steele, A.; Fries, M. D.

    2016-05-01

    The chemical species in cherts and glass fragments were analyzed using micro Raman spectroscopy in conjunction with measurements of heavy noble gas isotopes to characterize hydrothermally derived sedimentary environments.

  17. Micro-Raman spectroscopy study of ALVAC virus infected chicken embryo cells

    NASA Astrophysics Data System (ADS)

    Misra, Anupam K.; Kamemoto, Lori E.; Hu, Ningjie; Dykes, Ava C.; Yu, Qigui; Zinin, Pavel V.; Sharma, Shiv K.

    2011-05-01

    Micro- Raman spectroscopic investigation of ALVAC virus and of normal chicken embryo fibroblast cells and the cells infected with ALVAC virus labeled with green fluorescence protein (GFP) were performed with a 785 nm laser. Good quality Micro-Raman spectra of the Alvac II virus were obtained. These spectra show that the ALVAC II virus contains buried tyrosine residues and the coat protein of the virus has α-helical structure. A comparison of Raman spectra of normal and virus infected chicken embryo fibroblast cells revealed that the virus infected cells show additional bands at 535, 928, and 1091 cm-1, respectively, corresponding to δ(C-O-C) glycosidic ring, protein α-helix, and DNA (O-P-O) modes. In addition, the tyrosine resonance double (833 and 855 cm-1) shows reversal in the intensity of the higher-frequency band as compared to the normal cells that can be used to identify the infected cells. In the C-H stretching region, the infected cells show bands with higher intensity as compared to that of the corresponding bands in the normal cells. We also found that the presence of GFP does not affect the Raman spectra of samples when using a 785 nm micro-Raman system because the green fluorescence wavelength of GFP is well below the Stokes-Raman shifted spectral region.

  18. Composition and strain in thin Si1-xGex virtual substrates measured by micro-Raman spectroscopy and x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Perova, T. S.; Wasyluk, J.; Lyutovich, K.; Kasper, E.; Oehme, M.; Rode, K.; Waldron, A.

    2011-02-01

    Micro-Raman spectroscopy was employed for the determination of the germanium content, x and strain, ɛ, in ultrathin SiGe virtual substrates grown directly on Si by molecular beam epitaxy. The growth of highly relaxed SiGe layers was achieved by the introduction of point defects at a very low temperature during the initial stage of growth. SiGe virtual substrates with thicknesses in the range 40-200 nm with a high Ge content (up to 50%) and degree of relaxation, r, in the range 20%-100% were investigated using micro-Raman spectroscopy and x-ray diffraction (XRD) techniques. The Ge content, x, and strain, ɛ, were estimated from equations describing Si-Si, Si-Ge, and Ge-Ge Raman vibrational modes, modified in this study for application to thin SiGe layers. The alteration of the experimentally derived equations from previous studies was performed using independent data for x and r obtained from XRD reciprocal space maps. A number of samples consisting of a strained-silicon (s-Si) layer deposited on a SiGe virtual substrate were also analyzed. The stress value for the s-Si varied from 0.54 to 2.75 GPa, depending on the Ge-content in the virtual substrates. These results are in good agreement with theoretically predicted values.

  19. Extended x-ray absorption fine structure and micro-Raman spectra of Bridgman grown Cd1-xZnxTe ternary alloys

    NASA Astrophysics Data System (ADS)

    Talwar, Devki N.; Feng, Zhe Chuan; Lee, Jyh-Fu; Becla, P.

    2014-03-01

    We have performed low-temperature micro-Raman scattering and extended x-ray absorption fine-structure (EXAFS) measurements on the Bridgman-grown bulk zinc-blende Cd1-x Zn x Te (1.0 ≧̸ x ≧̸ 0.03) ternary alloys to comprehend their structural and lattice dynamical properties. The micro-Raman results are carefully appraised to authenticate the classical two-phonon mode behavior insinuated by far-infrared (FIR) reflectivity study. The composition-dependent EXAFS experiments have revealed a bimodal distribution of the nearest-neighbor bond lengths—its analysis by first-principles bond-orbital model enabled us to estimate the lattice relaxations around Zn/Cd atoms in CdTe/ZnTe to help evaluate the necessary force constant variations for constructing the impurity-perturbation matrices. The simulated results of impurity vibrational modes by average-t-matrix Green’s function (ATM-GF) theory has put our experimental findings of the gap mode ˜153 cm-1 near x ≈ 1 on a much firmer ground.

  20. Rheological and micro-Raman time-series characterization of enzyme sol-gel solution toward morphological control of electrospun fibers

    NASA Astrophysics Data System (ADS)

    Oriero, Dennis A.; Weakley, Andrew T.; Aston, D. Eric

    2012-04-01

    Rheological and micro-Raman time-series characterizations were used to investigate the chemical evolutionary changes of silica sol-gel mixtures for electrospinning fibers to immobilize an enzyme (tyrosinase). Results of dynamic rheological measurements agreed with the expected structural transitions associated with reacting sol-gel systems. The electrospinning sols exhibited shear-thinning behavior typical of a power law model. Ultrafine (200-300 nm diameter) fibers were produced at early and late times within the reaction window of approximately one hour from initial mixing of sol solutions with and without enzyme; diameter distributions of these fibers showed much smaller deviations than expected. The enzyme markedly increased magnitudes of both elastic and viscous moduli but had no significant impact on final fiber diameters, suggesting that the shear-thinning behavior of both sol-gel mixtures is dominant in the fiber elongation process. The time course and scale for the electrospinning batch fabrication show strong correlations between the magnitudes in rheological property changes over time and the chemical functional group evolution obtained from micro-Raman time-series analysis of the reacting sol-gel systems.

  1. The effects of machine parameters on residual stress determined using micro-Raman spectroscopy

    SciTech Connect

    Sparks, R.G.; Enloe, W.S.; Paesler, M.A.

    1988-12-01

    The effects of machine parameters on residual stresses in single point diamond turned silicon and germanium have been investigated using micro-Raman spectroscopy. Residual stresses were sampled across ductile feed cuts in < 100 > silicon and germanium which were single point diamond turned using a variety of feed rates, rake angles and clearance angles. High spatial resolution micro-Raman spectra (1{mu}m spot) were obtained in regions of ductile cutting where no visible surface damage was present. The use of both 514-5nm and 488.0nm excitation wavelengths, by virtue of their differing characteristic penetration depths in the materials, allowed determinations of stress profiles as a function of depth into the sample. Previous discussions have demonstrated that such Raman spectra will exhibit asymmetrically broadened peaks which are characteristic of the superposition of a continuum of Raman scatterers from the various depths probed. Depth profiles of residual stress were obtained using computer deconvolution of the resulting asymmetrically broadened raman spectra.

  2. High-quality cubic and hexagonal InN crystals studied by micro-Raman scattering and electron backscatter diffraction

    NASA Astrophysics Data System (ADS)

    Kamimura, Jumpei; Ramsteiner, Manfred; Jahn, Uwe; Lu, Cheng-Ying James; Kikuchi, Akihiko; Kishino, Katsumi; Riechert, Henning

    2016-04-01

    Large InN microcrystals grown by molecular beam epitaxy are investigated by micro-Raman spectroscopy and electron backscatter diffraction (EBSD). High-quality (phonon linewidths between 1.5 and 2 cm-1) cubic and hexagonal crystals are identified with Raman mapping by the observation of the respective characteristic phonon modes. The unexpected occurrence of metastable cubic InN crystals is confirmed by EBSD measurements. The cubic microcrystals are revealed by EBSD to be single-crystalline and to exhibit  <1 1 1>  orientation. The transverse (TO) and longitudinal-optical (LO) zone-center phonon frequencies of cubic InN are found to be 463 and 584 cm-1, respectively. The bulk carrier density in the microcrystals lies in the range of 2-3  ×  1017 cm-3 as determined by the analysis of LO phonon-plasmon-coupled modes in the Raman spectra.

  3. Micro-Raman spectroscopy of selected solid U/sub x/O/sub y/F/sub z/ compounds

    SciTech Connect

    Armstrong, D. P.; Jarabek, R. J.; Fletcher, W. H.

    1989-03-01

    Micro-Raman spectroscopy has been utilized to examine the spectra of solid samples of ..cap alpha..-UF/sub 5/, ..beta..-UF/sub 5/, UF/sub 6/, three types of UO/sub 2/F/sub 2/, the powder residue from a static UF/sub 6/ release, and ..gamma..-UO/sub 3/. The spectra are presented and compared to previous literature values, with new features indicated where appropriate. With the implied constraint of proper sample handling, micro-Raman spectroscopy is a useful technique for the ready identification of uranium fluorides, oxyfluorides, and oxides.

  4. In situ polarized micro-Raman investigation of periodic structures realized in liquid-crystalline composite materials.

    PubMed

    Castriota, Marco; Fasanella, Angela; Cazzanelli, Enzo; De Sio, Luciano; Caputo, Roberto; Umeton, Cesare

    2011-05-23

    In situ polarized micro-Raman Spectroscopy has been utilized to determine the liquid crystal configuration inside a periodic liquid crystalline composite structure made of polymer slices alternated to films of liquid crystal. Liquid crystal, Norland Optical Adhesive (NOA-61) monomer and its polymerized form have been investigated separately. The main Raman features, used as markers for the molecular orientation estimation, have been identified. In situ polarized Raman spectra indicate that the orientation of the liquid crystal director inside the structure is perpendicular to its polymeric slices. Results show the usefulness of in situ polarized micro-Raman spectroscopy to investigate liquid crystalline composite structures. PMID:21643304

  5. Local residual stress monitoring of aluminum nitride MEMS using UV micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Choi, Sukwon; Griffin, Benjamin A.

    2016-02-01

    Localized stress variation in aluminum nitride (AlN) sputtered on patterned metallization has been monitored through the use of UV micro-Raman spectroscopy. This technique utilizing 325 nm laser excitation allows detection of the AlN E2(high) phonon mode in the presence of metal electrodes beneath the AlN layer with a high spatial resolution of less than 400 nm. The AlN film stress shifted 400 MPa from regions where AlN was deposited over a bottom metal electrode versus silicon dioxide. Across wafer stress variations were also investigated showing that wafer level stress metrology, for example using wafer curvature measurements, introduces large uncertainties for predicting the impact of AlN residual stress on the device performance.

  6. Measurement of residual stress in a multi-layer semiconductor heterostructure by micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Qiu, Wei; Cheng, Cui-Li; Liang, Ren-Rong; Zhao, Chun-Wang; Lei, Zhen-Kun; Zhao, Yu-Cheng; Ma, Lu-Lu; Xu, Jun; Fang, Hua-Jun; Kang, Yi-Lan

    2016-07-01

    Si-based multilayer structures are widely used in current microelectronics. During their preparation, some inhomogeneous residual stress is induced, resulting in competition between interface mismatching and surface energy and even leading to structure failure. This work presents a methodological study on the measurement of residual stress in a multi-layer semiconductor heterostructure. Scanning electron microscopy (SEM), micro-Raman spectroscopy (MRS), and transmission electron microscopy (TEM) were applied to measure the geometric parameters of the multilayer structure. The relationship between the Raman spectrum and the stress/strain on the [100] and [110] crystal orientations was determined to enable surface and cross-section residual stress analyses, respectively. Based on the Raman mapping results, the distribution of residual stress along the depth of the multi-layer heterostructure was successfully obtained.

  7. Stress transfer of a Kevlar 49 fiber pullout test studied by micro-Raman spectroscopy.

    PubMed

    Lei, Zhenkun; Wang, Quan; Qiu, Wei

    2013-06-01

    The interfacial stress transfer behavior of a Kevlar 49 aramid fiber-epoxy matrix was studied with fiber pullout tests, the fibers of which were stretched by a homemade microloading device. Raman spectra on the embedded fiber were recorded by micro-Raman spectroscopy, under different strain levels. Then, the fiber axial stress was obtained by the relationship between the stress and Raman shift of the aramid fiber. Experimental results revealed that the fiber axial stress increased significantly with the load. The shear stress concentration occurred at the fiber entry to the epoxy resin. Thus, interfacial friction stages exist in the debonded fiber segment, and the interfacial friction shear stress is constant within one stage. The experimental results are consistent with the theoretical model predictions. PMID:23735244

  8. Local residual stress monitoring of aluminum nitride MEMS using UV micro-Raman spectroscopy

    DOE PAGESBeta

    Choi, Sukwon; Griffin, Benjamin A.

    2016-01-06

    Localized stress variation in aluminum nitride (AlN) sputtered on patterned metallization has been monitored through the use of UV micro-Raman spectroscopy. This technique utilizing 325 nm laser excitation allows detection of the AlN E2(high) phonon mode in the presence of metal electrodes beneath the AlN layer with a high spatial resolution of less than 400 nm. The AlN film stress shifted 400 MPa from regions where AlN was deposited over a bottom metal electrode versus silicon dioxide. Thus, across wafer stress variations were also investigated showing that wafer level stress metrology, for example using wafer curvature measurements, introduces large uncertaintiesmore » for predicting the impact of AlN residual stress on the device performance.« less

  9. MicroRaman Spectroscopy and Raman Imaging of Basal Cell Carcinoma

    NASA Astrophysics Data System (ADS)

    Short, M. A.; Zeng, H.; Lui, H.

    2005-03-01

    We have measured the Raman spectra of normal and cancerous skin tissues using a confocal microRaman spectrograph with a sub-micron spatial resolution. We found that the Raman spectrum of a cell nucleolus is different from the spectra measured outside the nucleolus and considerably different from those measured outside the nucleus. In addition, we found significant spectroscopic differences between normal and cancer-bearing sites in the dermis region. In order to utilize these differences for non-invasive skin cancer diagnosis, we have developed a Raman imaging system that clearly demonstrates the structure, location and distribution of cells in unstained skin biopsy samples. Our method is expected to be useful for the detection and characterization of skin cancer based on the known distinct cellular differences between normal and malignant skin.

  10. Characterization of biofumigated Ralstonia solanacearum cells using micro-Raman spectroscopy and electron microscopy.

    PubMed

    Paret, Mathews L; Sharma, Shiv K; Alvarez, Anne M

    2012-01-01

    Essential oils of palmarosa, lemongrass, and eucalyptus have shown promise as biofumigants for control of the bacterial wilt disease of edible ginger (Zingiber officinale) caused by Ralstonia solanacearum race 4 in previous potting medium studies. Biochemical changes in R. solanacearum cells were evaluated with micro-Raman spectroscopy following treatment with essential oils at different concentrations (0.04, 0.07, and 0.14% [vol/vol] of culture medium) and changes in cell structure were observed using electron microscopy. All treatments except palmarosa oil at 0.04% caused significant reductions in levels of amino acids, purine and pyrimidine bases of nucleic acids, carbohydrates, and lipids, as indicated by significant reduction in Raman peak heights at 621, 1,003, and 1,031 inverse centimeters (cm(-1)) (phenylalanine); 643, 827, 852, 1,158, and 1,172 cm(-1) (tyrosine); 758 cm(-1) (tryptophan); 725, 782, 1,337, and 1,578 cm(-1) (adenine, cytosine plus uracil, adenine, and adenine plus guanine, respectively); 1,097 cm(-1) (carbohydrates); and 1,127, 1,450, and 2,932 cm(-1) (lipids) compared with untreated controls. Lemongrass oil treatments were the most effective in degrading cellular components. Scanning electron microscopy of palmarosa and lemongrass-oil-treated cells showed rupture of cell walls and cell debris but no degradation was noted for eucalyptus-oil-treated cells. Palmarosa- and lemongrass-oil-treated cells were positively stained with uranyl acetate when viewed by transmission electron microscopy whereas controls and eucalyptus-oil-treated cells were negatively stained, indicating that the cell membranes were intact. The viability of eucalyptus-oil-treated cells was confirmed by cell culture following treatment. Micro-Raman spectroscopy is a powerful tool which can be further employed to better understand effects of fumigants and other bactericides on bacterial cells. PMID:21899389

  11. Infrared extinction spectroscopy and micro-Raman spectroscopy of select components of mineral dust mixed with organic compounds

    NASA Astrophysics Data System (ADS)

    Laskina, Olga; Young, Mark A.; Kleiber, Paul D.; Grassian, Vicki H.

    2013-06-01

    Radiative transfer calculations as well as satellite and ground-based retrieval algorithms often use Mie theory to account for atmospheric mineral dust. However, the approximations used in Mie theory are often not appropriate for mineral dust and can lead to inaccuracies in modeling optical properties. Analytic models that are based on Rayleigh theory and account for particle shapes can offer significant advantages when used to model the IR extinction of mineral dust in the accumulation size mode. Here we extend our investigations of the IR optical properties of mineral dust to include samples that have been processed with organic acids. In particular, we aerosolize several individual components of mineral dust with organic compounds that are common in the atmosphere. Through online and offline analysis of the resulting aerosol particles combining Fourier transform infrared (FTIR) extinction spectroscopy, micro-Raman spectroscopy, and scanning electron microscopy, we have identified three distinct outcomes of the interactions, which depend on the nature of the mineral and the organic acid: reactions with segregation of the products within the particle, formation of a uniform coating on the particle, or a formation of external mixture when there is no significant chemical interaction. Analysis of FTIR extinction spectra of the different dust components that have undergone processing shows red shifts of the prominent IR resonance peaks. The extent of the red shift, which varies from 2 to 10 cm-1, depends on the mineral and the nature of the interaction. Spectral simulations showed that the deviation from Mie theory becomes even more pronounced for these processed mineral dust aerosol components.

  12. Chemical bonding and atomic structure of Rb + exchanged KTiOPO4 waveguides probed by micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Tuschel, David D.; Paz-Pujalt, Gustavo R.; Risk, William P.

    1995-02-01

    Channel waveguides of Rb+ exchanged single-crystal KTiOPO4 were studied by micro-Raman spectroscopy. Rb+ exchange causes a disruption of the long-range translational (crystal) symmetry of the lattice and a tilting of the TiO6 octahedra. The ability to nondestructively map the chemical and physical structure related to the optical properties of channel waveguides is demonstrated.

  13. Characterization of Organic Materials in the Xenolithic Clasts in Sharps (H3.4) Meteorite Using Micro-Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Chan, Q. H. S.; Zolensky, M. E.; Bodnar, R. J.; Kebukawa, Y.

    2015-01-01

    Graphitization of carbon is an irreversible process which alters the structure of graphitic materials in response to the increase in metamorphic grade (temperature and/or pressure). Carbonaceous materials offer a reliable geothermometer as their Raman spectra change systematically with increasing metamorphic grade. In this study, we identified carbonaceous materials in the xenolithic clasts in Sharps and interpreted their metamorphic history by revealing the structural organization (order) of the polyaromatic organic phases using micro-Raman spectroscopy.

  14. Study on the degradation of PLEDs by in-situ micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoxuan; Qin, Zhe; Lin, Haibo; Xu, Wei

    2007-11-01

    Electro luminescence spectra and in-suit micro-Raman spectra was used to study voltaic aging of organic light emitting devices with two kinds of conjugated macromolecule polymer emission layer, one is called PFO-BT15 and the other is poly (2-(4-Ethylhexyl) phenyl-1 , 4-phenylene vinylene) (P-PPV) polymer. The first device has a configuration of ITO glass/ PEDOT( 120nm ) PFO-BT15(80nm)/Ba( 4nm )/Al(200nm) , and we encapsulated the cathode of diode with epoxy resin to reduce the entrance of oxygen and water. After long time current stress, the electro luminescent spectra and Raman spectra show that the polymer device's molecular configuration of polymer layer is unchanged , but the PEDOT anode's breakage which lead to the emission failure of the device, which indicates that this kind of polymer materials have relatively steady photoelectric performance . The second device, during current stress , the reduction of conjugation length is provided by Raman spectroscopy. This reduction of the conjugation length , which dramatically increases the resistance and cuts off the current density , was the main reason for the failure of lighting. These findings provide an important insight into the intrinsic degradation mechanisms of the polymer LEDs and help in the development of even more stable devices.

  15. Microstructure and micro-Raman studies of nitridation and structure transition of gallium oxide nanowires

    SciTech Connect

    Ning, J.Q.; Xu, S.J.; Wang, P.W.; Song, Y.P.; Yu, D.P.; Shan, Y.Y.; Lee, S.T.; Yang, H.

    2012-11-15

    Here we present a detailed study on nitridation and structure transition in monoclinic gallium oxide ({beta}-Ga{sub 2}O{sub 3}) nanowires grown on Si substrates with chemical vapor phase epitaxy. The nanowires were systematically nitridated at different temperatures. Their morphologies and microstructures were precisely characterized using field-emission scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and confocal micro-Raman spectroscopy. It is found that heat treatment of Ga{sub 2}O{sub 3} nanowires in the gas of ammonia results in rich substructures including the Ga{sub 2}O{sub 3} phase, the crystalline GaN phase, and other meta structures. The identification of these structures helps to understand some interesting phenomena observed in nanostructures, such as the microstructural origin of the unknown Raman lines in GaN nanowires. - Highlights: Black-Right-Pointing-Pointer Nitridation and structure transition of Ga{sub 2}O{sub 3} significantly depend on temperature. Black-Right-Pointing-Pointer G-N bonds form at lower temperatures but the Ga{sub 2}O{sub 3} lattice is still dominant. Black-Right-Pointing-Pointer Amorphous GaN coexists with crystalline Ga{sub 2}O{sub 3} at higher temperatures. Black-Right-Pointing-Pointer Crystalline GaN with distinct morphology is obtained at much higher temperatures.

  16. An induction heating diamond anvil cell for high pressure and temperature micro-Raman spectroscopic measurements.

    PubMed

    Shinoda, Keiji; Noguchi, Naoki

    2008-01-01

    A new external heating configuration is presented for high-temperature diamond anvil cell instruments. The supporting rockers are thermally excited by induction from an externally mounted copper coil passing a 30 kHz alternating current. The inductive heating configuration therefore avoids the use of breakable wires, yet is capable of cell temperatures of 1100 K or higher. The diamond anvil cell has no resistive heaters, but uses a single-turn induction coil for elevating the temperature. The induction coil is placed near the diamonds and directly heats the tungsten carbide rockers that support the diamond. The temperature in the cell is determined from a temperature-power curve calibrated by the ratio between the intensities of the Stokes and anti-Stokes Raman lines of silicon. The high-pressure transformation of quartz to coesite is successfully observed by micro-Raman spectroscopy using this apparatus. The induction heating diamond anvil cell is thus a useful alternative to resistively heated diamond anvil cells. PMID:18248060

  17. Bacterial identification in real samples by means of micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Rösch, Petra; Stöckel, Stephan; Meisel, Susann; Bossecker, Anja; Münchberg, Ute; Kloss, Sandra; Schumacher, Wilm; Popp, Jürgen

    2011-07-01

    Pathogen detection is essential without time delay especially for severe diseases like sepsis. Here, the survival rate is dependent on a prompt antibiosis. For sepsis three hours after the onset of shock the survival rate of the patient drops below 60 %. Unfortunately, the results from standard diagnosis methods like PCR or microbiology can normally be received after 12 or 36 h, respectively. Therefore diagnosis methods which require less cultivation or even no cultivation at all have to be established for medical diagnosis. Here, Raman spectroscopy, as a vibrational spectroscopic method, is a very sensitive and selective approach and monitors the biochemical composition of the investigated sample. Applying micro-Raman spectroscopy allows for a spatial resolution below 1 μm and is therefore in the size range of bacteria. Raman spectra of bacteria depend on the physiological status. Therefore, the databases require the inclusion of the necessary environmental parameters such as temperature, pH, nutrition, etc. Such large databases therefore require a specialized chemometric approach, since the variation between different strains is small. In this contribution we will demonstrate the capability of Raman spectroscopy to identify pathogens without cultivation even from real environmental or medical samples.

  18. Micro-Raman investigation of thin lateral epitaxial overgrown GaN/sapphire(0001) films

    NASA Astrophysics Data System (ADS)

    Chaldyshev, V. V.; Pollak, Fred H.; Pophristic, M.; Guo, S. P.; Ferguson, I.

    2002-12-01

    Using micro-Raman spectroscopy we have investigated the n dopant and strain distribution in lateral epitaxial overgrowth technique GaN films grown by metalorganic chemical vapor deposition on the sapphire (0001) substrates with SiNx masks. The widths of the mask stripes were 2, 4, 8, or 16 μm, while the mask windows were always 4 μm wide. In the case of narrow stripes (2 and 4 μm), when the overgrowth wings were well coalesced, the films were found to be fairly uniform with a background n doping of (4±2)×1017cm-3. The GaN wings in the samples with 8 and 12 μm stripes did not coalesce, leaving "V"-shaped and trapezoidal grooves, respectively. In the latter case, additional doping [n=(6.5±0.6)×1017 cm-3] of the wing area was revealed, which may be due to surface diffusion of Si atoms from the SiNx mask to the GaN growth front and their incorporation into the growing film.

  19. Grain orientation, texture, and internal stress optically evaluated by micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Becker, M.; Scheel, H.; Christiansen, S.; Strunk, H. P.

    2007-03-01

    We present a method to experimentally determine the components of stress tensors within grains of multicrystalline materials by micro-Raman spectroscopy. This method is applied to multicrystalline silicon wafers as they are produced for solar cells. Currently, μ-Raman spectroscopy is intensively used to measure stresses in silicon wafers, structures, and devices of known crystallographic orientations. For these cases, the determination of stresses from Raman peak shifts is straightforward. In multicrystalline silicon, however, arbitrary grain orientations complicate the determination of stress tensor components, which depend on the crystallographic orientations of the particular grains. The Raman intensities depend on the polarization direction of the incident and scattered laser light and again on the crystallographic grain orientations. This intensity dependence is used to determine the crystallographic grain orientations. Once the orientation is determined, the components of the stress tensor (with respect to a fixed reference coordinate system—the sample stage), can be calculated numerically from the Raman peak shifts. As examples, we determine (i) the stress components of a nearly plane stress state around the tip of a microcrack and (ii) the stress components at a grain boundary in a multicrystalline silicon wafer.

  20. Preliminary micro-Raman images of normal and malignant human skin cells

    NASA Astrophysics Data System (ADS)

    Short, Michael A.; Lui, Harvey; McLean, David I.; Zeng, Haishan; Chen, Michael X.

    2006-02-01

    Micro-Raman spectroscopy covering a frequency range from 200 to 4000 cm -1 was used to image human skin melanocytes and keratinocytes with a spatial resolution of 0.5 μm. The cells were either cultivated on glass microscope slides or were located within thin sections of skin biopsies mounted on low fluorescence BaF II. A commercially available system was used to obtain the spectra utilizing a x100 long working distance objective with a numerical aperture of 0.8, and a cooled CCD. Both 633 and 515 nm excitations were tried, although the latter proved to be more effcient at producing Raman emission mostly due to the 1/λ 4 dependence in light scattering. Fluorescence emission from the cells was surprisingly low. The excitation power at the sample was kept below about 2 mW to avoid damaging the cells; this was the limiting factor on how quickly a Raman image could be obtained. Despite this diffculty we were able to obtain Raman images with rich information about the spectroscopic and structural features within the cytoplasm and cell nuclei. Differences were observed between the Raman images of normal and malignant cells. Spectra from purified DNA, RNA, lipids, proteins and melanin were obtained and these spectra were compared with the skin cell spectra with the aim of understanding how they are distributed over a cell and how the distribution changes between different cells.

  1. A micro-Raman and infrared study of several Hayabusa category 3 (organic) particles

    NASA Astrophysics Data System (ADS)

    Kitajima, Fumio; Uesugi, Masayuki; Karouji, Yuzuru; Ishibashi, Yukihiro; Yada, Toru; Naraoka, Hiroshi; Abe, Masanao; Fujimura, Akio; Ito, Motoo; Yabuta, Hikaru; Mita, Hajime; Takano, Yoshinori; Okada, Tatsuaki

    2015-02-01

    Three category 3 (organic) particles (RB-QD04-0001, RB-QD04-0047-02, and RA-QD02-0120) and so-called `white object' found in the sample container have been examined by micro-Raman and infrared (IR) spectroscopy. In addition, several artificial substances that could occur as possible contaminants and chondritic insoluble organic matter (IOM) prepared from the Murchison CM2 chondrite were analyzed. The Raman spectra of the particles show broad G-band and weak D-band. The G-band parameters plot in the disordered region and close to the artifact produced from a Viton glove after laser exposure rather than chondritic IOM. The particles were therefore originally at low maturity level, suggesting that they have not experienced strong heating and are therefore not related to the LL4-6 parent body. The IR spectra are not similar to that of chondritic IOM. Furthermore, the particles cannot be identified as some artificial carbonaceous substances, including the white object, which are the possible contaminants, examined in this investigation. Although it cannot be determined exactly whether the three category 3 particles are extraterrestrial, the limited IR and Raman results in this investigation strongly suggest their terrestrial origin. Although they could not be directly related to the artificial contaminants examined in this investigation, they may yet be reaction products from similar substances that flew on the mission. In particular, RB-QD04-0047-02 shows several infrared spectral absorption bands in common with the `white object.' This may relate to the degradation of a polyimide/polyamide resin.

  2. Biochemical characterization of Gram-positive and Gram-negative plant-associated bacteria with micro-Raman spectroscopy.

    PubMed

    Paret, Mathews L; Sharma, Shiv K; Green, Lisa M; Alvarez, Anne M

    2010-04-01

    Raman spectra of Gram-positive and Gram-negative plant bacteria have been measured with micro-Raman spectrometers equipped with 785 and 514.5 nm lasers. The Gram-positive bacteria Microbacterium testaceum, Paenibacillus validus, and Clavibacter michiganensis subsp. michiganensis have strong carotenoid bands in the regions 1155-1157 cm(-1) and 1516-1522 cm(-1) that differentiate them from other tested Gram-negative bacteria. In the Raman spectrum of Gram-positive bacteria Bacillus megaterium excited with 785 nm laser, the Raman bands at 1157 and 1521 cm(-1) are weak in intensity compared to other Gram-positive bacteria, and these bands did not show significant resonance Raman enhancement in the spectrum recorded with 514.5 nm laser excitation. The Gram-positive bacteria could be separated from each other based on the bands associated with the in-phase C=C (v(1)) vibrations of the polyene chain of carotenoids. None of the Gram-negative bacteria tested had carotenoid bands. The bacteria in the genus Xanthomonas have a carotenoid-like pigment, xanthomonadin, identified in Xanthomonas axonopodis pv. dieffenbachiae, and it is a unique Raman marker for the bacteria. The representative bands for xanthomonadin were the C-C stretching (v(2)) vibrations of the polyene chain at 1135-1136 cm(-1) and the in-phase C=C (v(1)) vibrations of the polyene chain at 1529-1531 cm(-1), which were distinct from the carotenoid bands of other tested bacteria. The tyrosine peak in the region 1170-1175 cm(-1) was the only other marker present in Gram-negative bacteria that was absent in all tested Gram-positives. A strong-intensity exopolysaccharide-associated marker at 1551 cm(-1) is a distinguishable feature of Enterobacter cloacae. The Gram-negative Agrobacterium rhizogenes and Ralstonia solanacearum were differentiated from each other and other tested bacteria on the basis of presence or absence and relative intensities of peaks. The principal components analysis (PCA) of the spectra

  3. Characterization of atmospheric aerosols in the Adirondack Mountains using PIXE, SEM/EDX, and Micro-Raman spectroscopies

    NASA Astrophysics Data System (ADS)

    Vineyard, M. F.; LaBrake, S. M.; Ali, S. F.; Nadareski, B. J.; Safiq, A. D.; Smith, J. W.; Yoskowitz, J. T.

    2015-05-01

    We are making detailed measurements of the composition of atmospheric aerosols collected in the Adirondack Mountains as a function of particle size using proton-induced X-ray emission, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and Micro-Raman spectroscopy. These measurements provide valuable data to help identify the sources and understand the transport, transformation, and effects of airborne pollutants in upstate New York. Preliminary results indicate significant concentrations of sulfur in small particles that can travel great distances, and that this sulfur may be in the form of oxides that can contribute to acid rain.

  4. Study of Hygroscopic Properties of Aminium Sulfate Particles Using Micro-Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Chu, Y.; Sauerwein, M.; Chan, C. K.

    2014-12-01

    As one of the organic nitrogen species, amines are alkaline compounds ubiquitously detected in the atmosphere. Amines have been found to have the potential to enhance atmospheric new particle formation via forming aminium sulfate salts as much as 1000-fold when compared with ammonia, albeit at relatively low atmospheric contents (Almeida et al., 2013). Hygroscopicity of aminium sulfate particles can affect their cloud condensation nuclei (CCN) activity, light scattering or absorption and reactivity in the atmosphere. However, aerosol thermodynamic models such as Extended Aerosol Thermodynamics Model (E-AIM) assume that aminium ions behave similarly to ammonium ions, thus resulting in inaccuracy in predictinghygroscopicity of such compounds. In this study, Micro-Raman spectroscopy was applied to investigate the hygroscopicity of mono-methylaminium sulfate (MMAS), di-methylaminium sulfate (DMAS), tri-methylaminium sulfate (TMAS) and mono-ethylaminium sulfate (MEAS) particles. Since amine can evaporate from stock solutions, Ion Chromatography was used to determine aminium-to-sulfate ion molar ratio (A/S) of studied particles. Results were compared with literature data (Clegg et al., 2013). Due to amine evaporation upon mixing, A/S of stock solutions for particle generation can be below 2.0. In fact, initial A/S were 1.59, 1.91, 1.33 and 2.00 of MMAS, DMAS, TMAS and MEAS particles respectively. Ultimately A/S decreased to 1.5 and 1.0 for DMAS and TMAS, suggesting di-methylamine (DMA) and tri-methylamine (TMA) evaporated from corresponding particles. A/S of MMAS and MEAS kept relatively constant during the relative humidity (RH) cycle in hygroscopic measurements. Unlike (NH4)2SO4, all studied aminium sulfate particles can take up water at low RH. MMAS and MEAS particles underwent phase transition at around 45% and 20% RH respectively, while particles of other aminium sulfates showed continuous hygroscopic trends. References: Almeida, J. et al., 2013. Nature 502, 359

  5. FT-IR and Micro-Raman spectroscopic studies of archaeological potteries recently excavated in Poompuhar, Tamilnadu, India

    NASA Astrophysics Data System (ADS)

    Kiruba, S.; Ganesan, S.

    2015-06-01

    Ancient ceramics are the abundant artifacts that give the knowledge of the past societies. Therefore it is of great importance to acquire knowledge about the chemical composition of the clay in archaeological artifacts. The spectroscopic techniques represent one of the most powerful tools to investigate the structure of all the materials and chemical composition of the cultural object like potteries. An attempt has been made in the present work to estimate the firing temperature of the archaeological pottery shreds excavated from the archaeological site Poompuhar in the state of Tamilnadu in India. The firing temperature of the archaeological pottery shreds were estimated by recording the corresponding FT-IR spectra in the range 4000-450 cm-1 and Micro Raman spectra in the range 1800-400 cm-1. The clay mineral present in the pottery samples are identified through FT-IR method and was confirmed with Micro Raman spectroscopy as both are complement to each other. The major primary mineral present in the samples is Kaolinite and the secondary mineral present is quartz and the accessory minerals present in the samples are hematite, magnetite and feldspar. The results of Raman spectra showed that the potters of this site used a mixture of clays as raw materials. The firing temperature for some of the samples did not exceed 800 °C which suggests the use of open fire.

  6. Micro-Raman investigations of InN-GaN core-shell nanowires on Si (111) substrate

    SciTech Connect

    Sangeetha, P.; Ramakrishnan, V.; Jeganathan, K.

    2013-06-15

    The electron-phonon interactions in InN-GaN core-shell nanowires grown by plasma assisted- molecular beam epitaxy (MBE) on Si (111) substrate have been analysed using micro-Raman spectroscopic technique with the excitation wavelength of 633, 488 and 325 nm. The Raman scattering at 633 nm reveals the characteristic E{sub 2} (high) and A{sub 1} (LO) phonon mode of InN core at 490 and 590 cm{sup -1} respectively and E{sub 2} (high) phonon mode of GaN shell at 573 cm{sup -1}. The free carrier concentration of InN core is found to be low in the order {approx} 10{sup 16} cm{sup -3} due to the screening of charge carriers by thin GaN shell. Diameter of InN core evaluated using the spatial correlation model is consistent with the transmission electron microscopic measurement of {approx}15 nm. The phonon-life time of core-shell nanowire structure is estimated to be {approx}0.4 ps. The micro-Raman mapping and its corresponding localised spectra for 325 nm excitation exhibit intense E{sub 2} (high) phonon mode of GaN shell at 573 cm{sup -1} as the decrease of laser interaction length and the signal intensity is quenched at the voids due to high spacing of NWs.

  7. FT-IR and micro-Raman spectroscopic studies of archaeological potteries recently excavated in Poompuhar, Tamilnadu, India.

    PubMed

    Kiruba, S; Ganesan, S

    2015-06-15

    Ancient ceramics are the abundant artifacts that give the knowledge of the past societies. Therefore it is of great importance to acquire knowledge about the chemical composition of the clay in archaeological artifacts. The spectroscopic techniques represent one of the most powerful tools to investigate the structure of all the materials and chemical composition of the cultural object like potteries. An attempt has been made in the present work to estimate the firing temperature of the archaeological pottery shreds excavated from the archaeological site Poompuhar in the state of Tamilnadu in India. The firing temperature of the archaeological pottery shreds were estimated by recording the corresponding FT-IR spectra in the range 4000-450 cm(-1) and Micro Raman spectra in the range 1800-400 cm(-1). The clay mineral present in the pottery samples are identified through FT-IR method and was confirmed with Micro Raman spectroscopy as both are complement to each other. The major primary mineral present in the samples is Kaolinite and the secondary mineral present is quartz and the accessory minerals present in the samples are hematite, magnetite and feldspar. The results of Raman spectra showed that the potters of this site used a mixture of clays as raw materials. The firing temperature for some of the samples did not exceed 800°C which suggests the use of open fire. PMID:25818307

  8. A micro-Raman spectroscopic investigation of leukemic U-937 cells treated with Crotalaria agatiflora Schweinf and the isolated compound madurensine

    NASA Astrophysics Data System (ADS)

    le Roux, Karlien; Prinsloo, Linda C.; Hussein, Ahmed A.; Lall, Namrita

    In South Africa traditional medicine plays an important role in primary health care and therefore it is very important that the medicinal use of plants is scientifically tested for toxicity and effectiveness. It was established that the ethanolic extract of the leaves of Crotalaria agatiflora, as well as the isolated compound madurensine, is moderately toxic against leukemic U-937 cells. Light microscopic investigations indicated that symptoms of cell death are induced during treatments, but flow cytometry analysis of treated cells, using annexin-V and propidium iodide, showed that apoptosis and necrosis are insignificantly induced. The Raman results suggested that protein extraction and DNA melting occur in the cells during treatment with the ethanolic extracts (IC50 value 73.9 μg/mL), drastically changing the molecular content of the cells. In contrast, treatment with madurensine (IC50 value 136.5 μg/mL), an isolated pyrrolizidine alkaloid from the ethanolic extract of the leaves, did not have the same effect. The results are also compared to that of cells treated with actinomycin D, a compound known to induce apoptosis. The investigation showed that micro-Raman spectroscopy has great promise to be used for initial screening of samples to determine the effects of different treatments on cancerous cell lines together with conventional methods. The results highlight the fact that for many natural products used for medicinal purposes, the therapeutic effect of the crude plant extract tends to be significantly more effective than the particular action of its individual constituents.

  9. Observation on the Ion Association Equilibria in NaNO3 Droplets Using Micro-Raman Spectroscopy

    SciTech Connect

    Yu, Jun-Ying; Zhang, Yun; Tan, See-Hua; Liu, Yong; Zhang, Yun-Hong

    2012-10-18

    Ion association ratios as a function of concentration were estimated in single NaNO3 droplets (5–60 μm) on a polytetrafluoroethylene (PTFE) substrate with molar water-to-solute ratios (WSRs) of 0.8–28 and bulk NaNO3 solutions with WSRs of 35–200 by combining micro-Raman spectroscopy and component band analysis. Concentrations of the NaNO3 droplets were accurately controlled by adjusting relative humidity (RH) in a sample chamber. As the WSRs decreased from 200 to 0.8, symmetric stretching band (ν1-NO3–) was observed to shift from 1047 to 1058 cm–1 along with a change in full width at half-maximum (fwhm) from ~10 to ~16 cm–1, indicative of formation of ion pairs with different structures. Through the component band analysis of the ν1-NO3– band, five bands centered at 1040.0, 1042.9, 1048.5, 1053.5, and 1057.0 cm–1 were identified and assigned to coupled wagging modes of water molecules hydrated with nitrate ions, free hydrated nitrate anions, solvent-shared ion pairs (SIPs), contact ion pairs (CIPs), and the complex ion aggregates (CIAs), respectively. There were large amounts of SIPs and CIPs in dilute NaNO3 solution even at an extremely low concentration (WSR ~ 200), and each accounted for 50% and 20% of total nitrate species, respectively. This finding is in good agreement with earlier reported observations. In the dilute solutions (45 < WSR < 200), there is the same amount of free hydrated ions transformed into SIPs as that of SIPs transformed into CIPs. As a result, the overall amount of SIPs remained unchanged over the concentration range. With a decrease in WSR from 45 to 0.8, the amounts of SIPs and free solvated NO3– ions kept decreasing, whereas the amount of CIPs rose to a maximum at WSR = 7 and then fell with a further decreasing WSR. Formation of CIAs started at WSR ~ 45, and its amount continuously

  10. CHEMICAL ANALYSIS OF STATIONARY SOURCE PARTICULATE POLLUTANTS BY MICRO-RAMAN SPECTROSCOPY

    EPA Science Inventory

    Analytical capability to identify the principal molecular species present in microparticles is demonstrated on the basis of Raman spectra of selected compounds and materials. Among the inorganic species studied are sulfates, nitrates, carbonates and oxides, for which Raman spectr...

  11. In-vitro micro-Raman study of tissue samples for detecting cervical and ovarian cancer with 785-nm laser excitation

    NASA Astrophysics Data System (ADS)

    Sharma, S. K.; Kamemoto, L. E.; Misra, A. K.; Goodman, M. T.; Luk, H. W.; Killeen, J. L.

    2010-04-01

    We present results of in vitro micro-Raman spectroscopy of normal and cancerous cervical and ovarian tissues excited with 785 nm near-infrared (NIR) laser. Micro- Raman spectra of squamous cervical cells of both cervix and ovarian tissues show significant differences in the spectra of normal and cancerous cells. In particular, several well-defined Raman peaks in the 775-975 cm-1 region are observed in the spectra of normal cervix squamous cells but are completely missing in the spectra of invasive cervical cancer cells. In the high-frequency 2800-3100 cm-1 region it is shown that the peak area under CH stretching band is much lower than the corresponding area in the spectra of normal cells. In the case of ovarian tissues, the micro-Raman spectra show noticeable spectral differences between normal cells and ovarian serous cancer cells. In particular, we observed the accumulation of β-carotene in ovarian serous cancer cells compared to normal ovarian cells from women with no ovarian cancer. The NIR micro-Raman spectroscopy offers a potential molecular technique for detecting cervical and ovarian cancer from the respective tissues.

  12. Micro-Raman spectroscopic study of nanolaminated Ti{sub 5}Al{sub 2}C{sub 3}

    SciTech Connect

    Zhang, H.; Li, Z. J.; Wang, X. H.; Xiang, H. M.; Zhou, Y. C

    2014-03-31

    Micro-Raman spectroscopic study and lattice dynamics calculations were conducted to study a recently identified layered ternary carbide, Ti{sub 5}Al{sub 2}C{sub 3}. The experimental Raman shifts were remarkably consistent with the calculated values. Polarized Raman spectrum was collected in the polycrystalline sample, which confirmed the theoretical symmetry assignment of the Raman modes. In addition, the atomic vibrations of the peaks at 192 cm{sup −1}, 311 cm{sup −1}, and 660 cm{sup −1} were identified to be the combination of the counterparts in Ti{sub 2}AlC and Ti{sub 3}AlC{sub 2}.

  13. Ultraviolet micro-Raman spectroscopy stress mapping of a 75-mm GaN-on-diamond wafer

    NASA Astrophysics Data System (ADS)

    Hancock, B. L.; Nazari, M.; Anderson, J.; Piner, E.; Faili, F.; Oh, S.; Twitchen, D.; Graham, S.; Holtz, M.

    2016-05-01

    Full-wafer stress mapping is accomplished using visible and ultraviolet (UV) micro-Raman spectroscopy of a 730-nm thick GaN layer integrated with diamond grown by chemical vapor deposition. The UV measurements taken from both sides of the wafer reveal a higher tensile stress of 0.86 ± 0.07 GPa at the free GaN surface compared to 0.23 ± 0.06 GPa from the GaN/diamond interface, each with good cross-wafer uniformity. Factors influencing the overall stress and stress gradient are understood based on relaxation from dislocations in the GaN which vary in density along the growth direction. Simulations incorporating a model for stress relaxation in the GaN elastic modulus adequately describe the observed dependence.

  14. MicroRaman, PXRD, EDS and microscopic investigation of magnesium calcite biomineral phases. The case of sea urchin biominerals

    NASA Astrophysics Data System (ADS)

    Borzęcka-Prokop, B.; Wesełucha-Birczyńska, A.; Koszowska, E.

    2007-02-01

    This study concerns Mg-calcite characterization (and in particular molecular structure and microstructural studies of mineral phases) of a sea urchin mineralised test and spines. Sea urchins are spiny sea animals (kingdom Animalia, phylum Echinodermata, class Echinoidea). Microscopic observations, SEM, EDS, PXRD and spectroscopic microRaman methods have been applied to characterize the biomineral parts of the sea urchin. The latter technique is very useful in research of biological systems and especially suitable for monitoring differences within biomineral phases exhibiting varieties of morphological forms. Crystalline magnesium calcium carbonate, Mg xCa 1- xCO 3 (magnesian calcite; space group R-3 cH; a = 4.9594(8) Å, c = 16.886(6) Å), has been identified as the predominant biomineral component.

  15. Kinetics of the drying process of an anti-adherent coating using Photothermal Radiometry and Micro-Raman

    NASA Astrophysics Data System (ADS)

    Hurtado-Castañeda, D. M.; Fernández, J.; Velázquez, R.; Estévez, M.; Vargas, S.; Rodríguez, R.; Rodríguez, M. E.

    2005-06-01

    The kinetics of the drying process of a new anti-adherent (anti-graffiti) polymeric coating containing organic solvent was determined using Photothermal Radiometry (PTR) and Micro-Raman (μ-R) Spectroscopy. PTR Spectroscopy was used to study, in real time, the kinetics of the drying process in samples protected with coatings with and without anti-adherent molecules. These were applied on a metal and silicon substrates. The PTR spectrum for coating without anti-adherent, shows a single relaxation time, while for coating containing anti-adherent shows two relaxation times corresponding to two different mechanisms: the solvent evaporation and the molecular re-arrangements of the two different molecular species present in the coating; the kinetic of the solvent evaporation is strongly dependent, as expected, on the solvent concentration.

  16. Study of stress distribution in a cleaved Si shallow trench isolation structure using confocal micro-Raman system

    NASA Astrophysics Data System (ADS)

    Tada, Tetsuya; Poborchii, Vladimir; Kanayama, Toshihiko

    2010-06-01

    We measured local stress distributions in a cleaved Si shallow trench isolation (STI) structure. We used a high-spatial-resolution confocal UV micro-Raman system with an excitation wavelength of 364 nm. The polarization dependence of Raman spectra enabled us to quantitatively estimate the stress direction and intensity on the (1¯10) cross-section. We observed stress relaxation due to the cleavage resulted in an abrupt change in the intensity and polarity of stress around the cross-sectional surface. Finite element method simulations reproduced well the measurement results and confirmed that this change was due to out-of-plane elastic deformation of the cleaved surface. This accurate comparison of the measurement data and the simulation is based on the feature that the UV Raman measurement selectively detects the surface regions, making this method particularly useful in stress distribution analyses.

  17. Characterization of azurite and lazurite based pigments by laser induced breakdown spectroscopy and micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Bicchieri, M.; Nardone, M.; Russo, P. A.; Sodo, A.; Corsi, M.; Cristoforetti, G.; Palleschi, V.; Salvetti, A.; Tognoni, E.

    2001-06-01

    The most commonly used blue pigments in medieval manuscripts are azurite and lapis-lazuli. The first one is a copper-based pigment; the coloring compound of the latter is lazurite, a sodium silicoaluminate in a sulfur matrix. Knowledge of the chemical composition of the materials is essential for the study of illuminated manuscripts. In this paper, micro-Raman and LIBS have been used for the study of azurite and lapis-lazuli, as well as different mixtures of these pigments applied to parchment to simulate an illuminated manuscript. The results of our work show the importance of using more than one technique for a good comprehension of a manuscript. In particular, the opportunity of combining elemental information (obtained from laser induced breakdown spectroscopy) and vibrational spectroscopy information (obtained from Raman) will be fully exploited.

  18. Confocal micro-Raman spectroscopy of single biological cells using optical trapping and shifted excitation difference techniques

    NASA Astrophysics Data System (ADS)

    Xie, Changan; Li, Yong-qing

    2003-03-01

    We report on the study of single biological cells with a confocal micro-Raman spectroscopy system that uses optical trapping and shifted excitation Raman difference technique. A tunable diode laser was used to capture a living cell in solution, confine it in the confocal excitation volume, and then excite the Raman scattering. The optical trapping allows us to lift the cell well off the cover plate so that the fluorescence interference from the plate can be effectively reduced. In order to further remove the interference of the fluorescence and stray light from the trapped cell, we employed a shifted excitation Raman difference technique with slightly tuned laser frequencies. With this system, high-quality Raman spectra were obtained from single optically trapped biological cells including E. coli bacteria, yeast cells, and red blood cells. A significant difference between control and heat-treated E. coli B cells was observed due to the denaturation of biomolecules.

  19. Micro-Raman study of copper hydroxychlorides and other corrosion products of bronze samples mimicking archaeological coins.

    PubMed

    Bertolotti, Giulia; Bersani, Danilo; Lottici, Pier Paolo; Alesiani, Marcella; Malcherek, Thomas; Schlüter, Jochen

    2012-02-01

    Three bronze samples created by CNR-ISMN (National Research Council-Institute of Nanostructured Materials) to be similar to Punic and Roman coins found in Tharros (OR, Sardinia, Italy) were studied to identify the corrosion products on their surfaces and to evaluate the reliability of the reproduction process. Micro-Raman spectroscopy was chosen to investigate the corroded surfaces because it is a non-destructive technique, it has high spatial resolution, and it gives the opportunity to discriminate between polymorphs and to correlate colour and chemical composition. A significant amount of green copper hydroxychlorides (Cu(2)(OH)(3)Cl) was detected on all the coins. Their discrimination by Raman spectroscopy was challenging because the literature on the topic is currently confusing. Thus, it was necessary to determine the characteristic peaks of atacamite, clinoatacamite, and the recently discovered anatacamite by acquiring Raman spectra of comparable natural mineral samples. Clinoatacamite, with different degrees of order in its structure, was the major component identified on the three coins. The most widespread corrosion product, besides hydroxychlorides, was the red copper oxide cuprite (Cu(2)O). Other corrosion products of the elements of the alloy (laurionite, plumbonacrite, zinc carbonate) and those resulting from burial in the soil (anatase, calcite, hematite) were also found. This study shows that identification of corrosion products, including discrimination of copper hydroxychlorides, could be accomplished by micro-Raman on valuable objects, for example archaeological findings or works of art, avoiding any damage because of extraction of samples or the use of a destructive analytical technique. PMID:21805316

  20. Investigating the Responses of Cronobacter sakazakii to Garlic-Drived Organosulfur Compounds: a Systematic Study of Pathogenic-Bacterium Injury by Use of High-Throughput Whole-Transcriptome Sequencing and Confocal Micro-Raman Spectroscopy

    PubMed Central

    Feng, Shaolong; Eucker, Tyson P.; Holly, Mayumi K.; Konkel, Michael E.

    2014-01-01

    We present the results of a study using high-throughput whole-transcriptome sequencing (RNA-seq) and vibrational spectroscopy to characterize and fingerprint pathogenic-bacterium injury under conditions of unfavorable stress. Two garlic-derived organosulfur compounds were found to be highly effective antimicrobial compounds against Cronobacter sakazakii, a leading pathogen associated with invasive infection of infants and causing meningitis, necrotizing entercolitis, and bacteremia. RNA-seq shows changes in gene expression patterns and transcriptomic response, while confocal micro-Raman spectroscopy characterizes macromolecular changes in the bacterial cell resulting from this chemical stress. RNA-seq analyses showed that the bacterial response to ajoene differed from the response to diallyl sulfide. Specifically, ajoene caused downregulation of motility-related genes, while diallyl sulfide treatment caused an increased expression of cell wall synthesis genes. Confocal micro-Raman spectroscopy revealed that the two compounds appear to have the same phase I antimicrobial mechanism of binding to thiol-containing proteins/enzymes in bacterial cells generating a disulfide stretching band but different phase II antimicrobial mechanisms, showing alterations in the secondary structures of proteins in two different ways. Diallyl sulfide primarily altered the α-helix and β-sheet, as reflected in changes in amide I, while ajoene altered the structures containing phenylalanine and tyrosine. Bayesian probability analysis validated the ability of principal component analysis to differentiate treated and control C. sakazakii cells. Scanning electron microscopy confirmed cell injury, showing significant morphological variations in cells following treatments by these two compounds. Findings from this study aid in the development of effective intervention strategies to reduce the risk of C. sakazakii contamination in the food production environment and on food contact surfaces

  1. Pigment analyses of a portrait and paint box of Turkish artist Feyhaman Duran (1886-1970): The EDXRF, FT-IR and micro Raman spectroscopic studies

    NASA Astrophysics Data System (ADS)

    Akyuz, Sevim; Akyuz, Tanil; Emre, Gulder; Gulec, Ahmet; Basaran, Sait

    2012-04-01

    The samples obtained from nine different places of Ataturk portrait (oil on canvas, 86 cm × 136 cm) by Feyhaman Duran (1886-1970), one of the famous Turkish painters of the 20th century, together with five pigment samples (two different white, two different yellow and blue), obtained as powders from artist's paint box, were analysed by EDXRF, FT-IR and micro-Raman spectroscopic methods, in order to characterise the pigments used by the artist. Informative Raman signals were not obtained from most of the samples of the portrait, due to huge fluorescence caused by the presence of impurities and organic materials in the samples, however the Raman spectrum of the sample from skin coloured part of the portrait and the pigment samples obtained from the paint box of the artist were found to be very informative to shed light on the determination of the pigments used. Analysis revealed the presences of chrome yellow (PbCrO4), strontium yellow (SrCrO4) and Cadmium yellow (CdS) as yellow, chromium oxides (Cr2O3 and Cr2O3·2H2O) as green, natural red ochre as red, brown ochre as brown and ivory black or bone black (C + Ca3(PO4)2) and manganese oxides (Mn2O3 and MnO2) as black pigments, in the composition of the Ataturk portrait. Lead white (2PbCO3·Pb(OH)2), calcite (CaCO3), barite (BaSO4), zinc white (ZnO) and titanium white (TiO2) were used as extenders to lighten the colours and/or as for ground level painting. Powder pigment samples, obtained from the paint box of artist, were found to be mixed pigments rather than pure ones.

  2. Micro-Raman spectroscopy of gem-quality chrysoprase from the Biga-Çanakkale region of Turkey

    NASA Astrophysics Data System (ADS)

    Hatipoğlu, Murat; Ören, Ufuk; Kibici, Yaşar

    2011-11-01

    The commercial quantities of gem-quality dark green chrysoprase are found as the fracture fillings covered with a weathering crust in the silicified serpentinites throughout the border of a metamorphic zone in the Biga-Çanakkale region of Turkey. However, the green-stained opaque quartz materials are also present in the same deposit, but these materials are common and in low-demand according to chrysoprase in terms of gemmological importance. Thus, it is necessary to distinguish these two similar materials from each other non-destructively. In addition, all chrysoprase roughs in this deposit also have alpha-quartz and moganite inclusions. Accordingly, dispersive (visible) confocal micro-Raman spectroscopy (DCμRS) allows us to distinguish clearly the chalcedonic-quartz silica phase (fibrous quartz (chalcedony)) from the crystalline-quartz silica phase (fine-grained alpha-quartz) in the case of both quartz inclusions in the chrysoprase material and itself of the green-stained quartz material in the same deposit. This study characterizes the Biga chrysoprase (Turkey) in terms of silica building phases, chemical content, and individual Raman bands, using several destructive and non-destructive analytical techniques. The Raman spectra show that the most characteristic intensive and the widest Raman bands peaked at about 498 and 460 cm -1 can be inferred to ν2 doubly symmetric bending mode of [SiO 4/M] centers. The "M" includes the some cationic substitutions of Si by Fe, Cr, Mn, As, Ni, Pb, Sb, and Zn, and K and Na as well. The second characteristic Raman band peaked at about 206 cm -1 can be inferred to single translational libration mode. The last readable Raman bands peaked at about 139 and 126 cm -1 can be inferred to doubly translational libration modes as well. In addition, the weaker Raman bands peaked at about 1577, 1430, 1303, 1160, 1082, 549, 394, 352, and 259 cm -1 are also present. As a result, the dispersive confocal micro-Raman spectrum of chrysoprase

  3. Contributed Review: Experimental characterization of inverse piezoelectric strain in GaN HEMTs via micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Bagnall, Kevin R.; Wang, Evelyn N.

    2016-06-01

    Micro-Raman thermography is one of the most popular techniques for measuring local temperature rise in gallium nitride (GaN) high electron mobility transistors with high spatial and temporal resolution. However, accurate temperature measurements based on changes in the Stokes peak positions of the GaN epitaxial layers require properly accounting for the stress and/or strain induced by the inverse piezoelectric effect. It is common practice to use the pinched OFF state as the unpowered reference for temperature measurements because the vertical electric field in the GaN buffer that induces inverse piezoelectric stress/strain is relatively independent of the gate bias. Although this approach has yielded temperature measurements that agree with those derived from the Stokes/anti-Stokes ratio and thermal models, there has been significant difficulty in quantifying the mechanical state of the GaN buffer in the pinched OFF state from changes in the Raman spectra. In this paper, we review the experimental technique of micro-Raman thermography and derive expressions for the detailed dependence of the Raman peak positions on strain, stress, and electric field components in wurtzite GaN. We also use a combination of semiconductor device modeling and electro-mechanical modeling to predict the stress and strain induced by the inverse piezoelectric effect. Based on the insights gained from our electro-mechanical model and the best values of material properties in the literature, we analyze changes in the E2 high and A1 (LO) Raman peaks and demonstrate that there are major quantitative discrepancies between measured and modeled values of inverse piezoelectric stress and strain. We examine many of the hypotheses offered in the literature for these discrepancies but conclude that none of them satisfactorily resolves these discrepancies. Further research is needed to determine whether the electric field components could be affecting the phonon frequencies apart from the inverse

  4. Contributed Review: Experimental characterization of inverse piezoelectric strain in GaN HEMTs via micro-Raman spectroscopy.

    PubMed

    Bagnall, Kevin R; Wang, Evelyn N

    2016-06-01

    Micro-Raman thermography is one of the most popular techniques for measuring local temperature rise in gallium nitride (GaN) high electron mobility transistors with high spatial and temporal resolution. However, accurate temperature measurements based on changes in the Stokes peak positions of the GaN epitaxial layers require properly accounting for the stress and/or strain induced by the inverse piezoelectric effect. It is common practice to use the pinched OFF state as the unpowered reference for temperature measurements because the vertical electric field in the GaN buffer that induces inverse piezoelectric stress/strain is relatively independent of the gate bias. Although this approach has yielded temperature measurements that agree with those derived from the Stokes/anti-Stokes ratio and thermal models, there has been significant difficulty in quantifying the mechanical state of the GaN buffer in the pinched OFF state from changes in the Raman spectra. In this paper, we review the experimental technique of micro-Raman thermography and derive expressions for the detailed dependence of the Raman peak positions on strain, stress, and electric field components in wurtzite GaN. We also use a combination of semiconductor device modeling and electro-mechanical modeling to predict the stress and strain induced by the inverse piezoelectric effect. Based on the insights gained from our electro-mechanical model and the best values of material properties in the literature, we analyze changes in the E2 high and A1 (LO) Raman peaks and demonstrate that there are major quantitative discrepancies between measured and modeled values of inverse piezoelectric stress and strain. We examine many of the hypotheses offered in the literature for these discrepancies but conclude that none of them satisfactorily resolves these discrepancies. Further research is needed to determine whether the electric field components could be affecting the phonon frequencies apart from the inverse

  5. Low laser power micro-Raman study of Co(1-x)Mn(x)Fe2O4 prepared by flash combustion method

    NASA Astrophysics Data System (ADS)

    Baraliya, J. D.

    2016-05-01

    Manganese substituted Cobalt ferrites of composition with nominal formula Co(1-x)Mn(x)Fe2O4 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) prepared by the Flash Combustion Method(FCM). The single phase spinel formation of nano ferrites was confirmed by X-ray diffraction techniques and micro - Raman spectroscopy. The particle size calculated from the Scherrer formula varied within 13 to 17 nm. Lattice parameter, nano particle size, and cation distribution were quantified as a function of the Mn-content in the range x = 0.0 to 1.0. Micro-Raman spectroscopic studies yielded convincing evidence for a transformation of the structure.

  6. Remote-Raman and Micro-Raman Studies of Solid CO2, CH4, Gas Hydrates and Ice

    NASA Technical Reports Server (NTRS)

    Sharma, S. K.; Misra, A. K.; Lucey, P. G.; Exarhos, G. J.; Windisch, C. F., Jr.

    2004-01-01

    It is well known that on Mars CO2 is the principal constituent of the thin atmosphere and on a seasonal basis CO2 snow and frost coats the polar caps. Also over 25% of the Martian atmosphere freezes out and sublimes again each year. The Mars Odyssey Emission Imaging system (THEMIS) has discovered water ice exposed near the edge of Mars southern perennials cap. In recent years, it has been suggested that in Martian subsurface CO2 may exist as gas hydrate (8CO2 + 44 H2O) with melting temperature of 10C. Since the crust of Mars has been stable for enough time there is also a possibility that methane formed by magmatic processes and/or as a byproduct of anaerobic deep biosphere activity to have raised toward the planet s surface. This methane would have been captured and stored as methane hydrate, which concentrates methane and water. Determination of abundance and distribution of these ices on the surface and in the near surface are of fundamental importance for understanding Martian atmosphere, and for future exploration of Mars. In this work, we have evaluated feasibility of using remote Raman and micro-Raman spectroscopy as potential nondestructive and non-contact techniques for detecting solid CO2, CH4 gas, and gas hydrates as well as water-ice on planetary surfaces.

  7. Vibrational dynamics of single-crystal YVO4 studied by polarized micro-Raman spectroscopy and ab initio calculations

    NASA Astrophysics Data System (ADS)

    Sanson, Andrea; Giarola, Marco; Rossi, Barbara; Mariotto, Gino; Cazzanelli, Enzo; Speghini, Adolfo

    2012-12-01

    The vibrational properties of yttrium orthovanadate (YVO4) single crystals, with tetragonal zircon structure, have been investigated by means of polarized micro-Raman spectroscopy and ab initio calculations. Raman spectra were taken at different polarizations and orientations carefully set by the use of a micromanipulator, so that all of the twelve Raman-active modes, expected on the basis of the group theory, were selected in turn and definitively assigned in wave number and symmetry. In particular the Eg(4) mode, assigned incorrectly in previous literature, has been observed at 387 cm-1. Moreover, the very weak Eg(1) mode, peaked at about 137 cm-1, was clearly observed only under some excitation wavelengths, and its peculiar Raman excitation profile was measured within a wide region of the visible. Finally, ab initio calculations based on density-functional theory have been performed in order to determine both Raman and infrared vibrational modes and to corroborate the experimental results. The rather good agreement between computational and experimental frequencies is slightly better than in previous computational works and supports our experimental symmetry assignments.

  8. Depth-resolved confocal micro-Raman spectroscopy for characterizing GaN-based light emitting diode structures

    SciTech Connect

    Chen, Wei-Liang; Lee, Yu-Yang; Chang, Yu-Ming; Chang, Chiao-Yun; Huang, Huei-Min; Lu, Tien-Chang

    2013-11-15

    In this work, we demonstrate that depth-resolved confocal micro-Raman spectroscopy can be used to characterize the active layer of GaN-based LEDs. By taking the depth compression effect due to refraction index mismatch into account, the axial profiles of Raman peak intensities from the GaN capping layer toward the sapphire substrate can correctly match the LED structural dimension and allow the identification of unique Raman feature originated from the 0.3 μm thick active layer of the studied LED. The strain variation in different sample depths can also be quantified by measuring the Raman shift of GaN A{sub 1}(LO) and E{sub 2}(high) phonon peaks. The capability of identifying the phonon structure of buried LED active layer and depth-resolving the strain distribution of LED structure makes this technique a potential optical and remote tool for in operando investigation of the electronic and structural properties of nitride-based LEDs.

  9. Micro-Raman studies of swift heavy ion irradiation induced structural and conformational changes in polyaniline nanofibers

    NASA Astrophysics Data System (ADS)

    Banerjee, Somik; Kumar, A.

    2010-09-01

    Polyaniline (PAni) nanofibers doped with camphor sulfonic acid have been irradiated with 90 MeV O 7+ ions at different fluences (3 × 10 10-1 × 10 12 ions/cm 2) using a 15UD Pelletron accelerator under ultra-high vacuum. XRD studies reveal a decrease in the domain length and an increase in the strain upon SHI irradiation. The increase in d-spacing corresponding to the (1 0 0) reflection of PAni nanofibers with increasing irradiation fluence has been attributed to the increase in the tilt angle of the chains with respect to the ( a, b ) basal plane of PAni. Decrease in the integral intensity upon SHI irradiation indicates amorphization of the material. Micro-Raman (μR) studies confirm amorphization of the PAni nanofibers and also show that the PAni nanofibers get de-doped upon SHI irradiation. μR spectroscopy also reveals a benzenoid to quinoid transition in the PAni chain upon SHI irradiation. TEM results show that the size of PAni nanofibers decreases with the increase in irradiation fluence, which has been attributed to the fragmentation of PAni nanofibers in the core of amorphized tracks caused by SHI irradiation.

  10. Microparticle electrodes and single particle microbatteries: electrochemical and in situ microRaman spectroscopic studies.

    PubMed

    Jebaraj, Adriel Jebin Jacob; Scherson, Daniel A

    2013-05-21

    Studies of the intrinsic electrochemical, structural, and electronic propertiesof microparticles of energy storage materials can provide much needed insight into the factors that control various aspects of the performance of technical electrodes for battery applications. This Account summarizes efforts made in our laboratories toward the development and implementation of methods for the in situ electrical, optical, and spectroscopic characterization of microparticles of a variety of such materials, including Ni hydroxide, Zn, carbon, and lithiated Mn and Co oxides. In the case of Ni hydroxide, the much darker appearance of NiOOH compared to the virtually translucent character of virgin Ni(OH)2 allowed for the spatial and temporal evolution of charge flow within spherical microparticles of Ni(OH)2 to be monitored in real time during the first scan toward positive potentials using computer-controlled video imaging. In situ Raman scattering measurements involving single microparticles of Zn harvested from a commercial Zn|MnO2 battery revealed that passive films formed in strongly alkaline solutions by stepping the potential from 1.55 V to either 0.7 or 0.8 V vs SCE displayed a largely enhanced feature at ca. 565 cm(-1) ascribed to a longitudinal optical phonon mode of ZnO, an effect associated with the presence of interstitial Zn and oxygen deficiencies in the lattice. In addition, significant amounts of crystalline ZnO could be detected only for passive films formed at the same two potentials after the electrodes had been roughened by a single passivation-reduction step. Quantitative correlations were found in the case of LiMn2O4 and KS-44 graphite between the Raman spectral properties and the state of charge. In the case of KS-44, a chemometrics analysis of the spectroscopic data in the potential region in which the transition between dilute phase 1 and phase 4 of lithiated graphite is known to occur made it possible to determine independently the fraction of each

  11. Polarized micro Raman scattering spectroscopy for curved edges of epitaxial graphene

    SciTech Connect

    Islam, Md. Sherajul Makino, T.; Hashimoto, A.; Bhuiyan, A. G.; Tanaka, S.

    2014-12-15

    This letter performed polarized microscopic laser Raman scattering spectroscopy on the curved edges of transferred epitaxial graphene on SiO{sub 2}/Si. The intensity ratio between the parallel and perpendicular polarized D band is evolved, providing a spectroscopy-based technique to probe the atomic-scale edge structures in graphene. A detailed analysis procedure for non-ideal disordered curved edges of graphene is developed combining the atomic-scale zigzag and armchair edge structures along with some point defects. These results could provide valuable information of the realistic edges of graphene at the atomic-scale that can strongly influence the performance of graphene-based nanodevices.

  12. Micro-Raman spectroscopy of tissue samples for oral pathology follow-up monitoring

    NASA Astrophysics Data System (ADS)

    Delfino, I.; Camerlingo, C.; Zenone, F.; Perna, G.; Capozzi, V.; Cirillo, N.; Gaeta, G. M.; Lepore, M.

    2010-04-01

    An "in vitro" study of Raman spectra from oral human tissues is reported in order to the develop a diagnostic method suitable for "in vivo" oral pathology follow-up. The investigated pathology is Pemphigus Vulgaris (PV) for which new techniques for guiding and monitoring therapy would be particularly useful. Raman spectra were obtained in the wavenumber regions from 1000 to 1800 cm-1 and 2700 to 3200 cm-1 from tissues from patients at different stages of pathology (active PV, under therapy and in PV remission stage) as confirmed by histopathological and immunofluorescence analysis. Differences in the spectra depending on tissue illness stage arise in 1150-1250 cm-1 (amide III) and 1420-1450 cm-1 (CH3 deformation) regions and around 1650 cm-1 (amide I) and 2930 cm-1 (CH3 symmetric stretch). A wavelet deconvolution procedure was applied to the spectra for better discriminating among the three different stages of illness and a linear regression analysis was used to fully exploit the content of information of Raman spectra.

  13. Recent advances in laser tweezers Raman spectroscopy (LTRS) for label-free analysis of single cells.

    PubMed

    Chan, James W

    2013-01-01

    Laser tweezers Raman spectroscopy (LTRS), a technique that integrates optical tweezers with confocal Raman spectroscopy, is a variation of micro-Raman spectroscopy that enables the manipulation and biochemical analysis of single biological particles in suspension. This article provides an overview of the LTRS method, with an emphasis on highlighting recent advances over the past several years in the development of the technology and several new biological and biomedical applications that have been demonstrated. A perspective on the future developments of this powerful cytometric technology will also be presented. PMID:23175434

  14. O electrolyte for bio-application

    NASA Astrophysics Data System (ADS)

    Naddaf, M.; Almariri, A.

    2014-09-01

    Porous silicon (PS) has been prepared in the dark by anodic etching of n+-type (111) silicon substrate in a HF:HCl:C2H5OH:H2O2:H2O electrolyte. The processed PS layer is characterized by means of photoluminescence (PL) spectroscopy, scanning electron microscope (SEM), water contact angle (CA) measurements, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and micro-Raman scattering. The CA of fresh PS layer is found to be ~142°. On aging at ambient conditions, the CA decreases gently to reach ~133° after 3 month, and then it is stabilized for a prolonged time of aging. The visible PL emission from the PS layer also exhibits a good stability against aging time. The FTIR and XPS measurements and analysis show that the stable aged PS layer has rather SiO2-rich surface. The micro/nanostructure nature of the PS layer is revealed from SEM and micro-Raman results and correlated to CA results. Stable hydrophobic surface of oxidized PS layer is attractive for bio-applications. The efficiency of the produced PS layers as an entrapping template for specific immobilization of IgG2a antibody via physical absorption process is demonstrated.

  15. Electric field-induced structural changes in pentacene-based organic thin-film transistors studied by in situ micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Cheng, H. L.; Chou, W. Y.; Kuo, C. W.; Tang, F. C.; Wang, Y. W.

    2006-04-01

    We have investigated the electric field-induced microscopic structural changes in polycrystalline pentacene-based organic transistors by using in situ micro-Raman spectroscopy. Extra vibrational modes resulting from molecular coupling effect in pentacene film were studied. The herringbone packing of pentacene molecules in solid film is affected by external field and the process is proven to be partially irreversible. In the meantime, in-phase coupling of the C-H bending mode was found to be highly related to the carrier transport of pentacene film. Obtained results suggest that optimal intermolecular π-orbital overlap of pentacene molecules is still a critical factor impacting the carrier transportation for pentacene film featuring polycrystalline morphology.

  16. Elemental and spectroscopic characterization of plasters from Fatih Mosque-Istanbul (Turkey) by combined micro-Raman, FTIR and EDXRF techniques.

    PubMed

    Akyuz, Tanil; Akyuz, Sevim; Gulec, Ahmet

    2015-10-01

    The characterization of the plasters and coloring agents of the wall paintings of Fatih Mosque have been performed using combined micro-Raman, FTIR and EDXRF techniques. The investigations show that the plaster used on the walls has mixed gypsum-lime binders. Cinnabar {HgS}, lead red {Pb3O4} and hematite {α-Fe2O3} were identified in the red surfaces. Blue color is attributed to ultramarine blue {Na8-10Al6Si6O24S2-4}. Green color is assigned to mixtures of green earth, copper phthalocyanine {Cu(C32Cl16N8)} and brochantite {CuSO4·3Cu(OH)2}. Strontium yellow {SrCrO4} and zinc white {ZnO} were also used to ensure the color tone. The results provide a basis for future restoration of wall paints. PMID:25989612

  17. Micro-Raman and FT-IR spectroscopic studies of ceramic shards excavated from ancient Stratonikeia city at Eskihisar village in West-South Turkey

    NASA Astrophysics Data System (ADS)

    Bahçeli, Semiha; Güleç, Gamze; Erdoğan, Hasan; Söğüt, Bilal

    2016-02-01

    In this study, micro-Raman and Fourier transformed infrared (FT-IR) spectroscopies, X-ray diffraction (XRD) and scanning electron microscope with energy dispersive X-ray (SEM-EDX) were used to characterize the mineralogical structures of pigments of four ceramic fragments in which one of them belongs to Hellenistic period (1st - IVth century BC) and other three ceramic shards belong to Early Rome (IVth century BC- 1st century AD) excavated from Stratonikeia ancient city. In the results of investigations on these four ceramic fragments, the various phases were identified: quartz, kaolinite, albit (or Na-feldspar), calcite, anastase, hematite and magnetite. Furthermore, the obtained findings indicate that firing temperature is about 800-850 °C for all the shards.

  18. Micro-Raman spectroscopy in the identification of wulfenite and vanadinite in a Sasanian painted stucco fragment of the Ghaleh Guri in Ramavand, western Iran.

    PubMed

    Holakooei, Parviz; Karimy, Amir-Hossein; Hasanpour, Ata; Oudbashi, Omid

    2016-12-01

    This paper reports the results of studies performed on a painted stucco fragment excavated at the Ghaleh Guri in Ramavand, western Iran, and dated back to the late Sasanian period (224-651AD). Analytical studies including micro-Raman spectroscopy (μ-Raman), micro-X-ray spectrometry (μ-XRF) and optical microscopy showed that red lead and vermilion were used as main pigments on this fragment. Moreover, carbon black was diagnosed to thinly cover some parts of the red lead. Peculiarly, wulfenite (PbMoO4) associated with vanadinite (Pb5(VO4)3Cl) was identified to compose a yellow stain sporadically dispersed on the other pigments. PMID:27372513

  19. The characterization of canvas painting by the Serbian artist Milo Milunović using X-ray fluorescence, micro-Raman and FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Damjanović, Lj.; Gajić-Kvaščev, M.; Đurđević, J.; Andrić, V.; Marić-Stojanović, M.; Lazić, T.; Nikolić, S.

    2015-10-01

    A canvas painting by Milo Milunović "The Inspiration of the poet" was studied by energy dispersive X-Ray fluorescence (EDXRF), micro-Raman and Fourier transform infrared (FTIR) spectroscopy in order to identify materials used by the artist and his painting technique. Study is perfomed combining in situ non-destructive method with the preparation and study of cross-section samples and raw fragments of the samples. Milo Milunović, an eminent painter from Balkan region, made a copy of the Nicolas Poussin's original painting in Louvre in 1926/27. Obtained results revealed following pigments on the investigated canvas painting: vermilion, minium, cobalt blue, ultramarine, lead white, zinc white, cadmium yellow, chrome-based green pigment and several earth pigments - red and yellow ocher, green earth and umber. Ground layer was made of lead white mixed with calcium carbonate.

  20. Micro-Raman study on the softening and stiffening of phonons in rutile titanium dioxide film: Competing effects of structural defects, crystallite size, and lattice strain

    SciTech Connect

    Gautam, Subodh K.; Singh, Fouran Sulania, I.; Kulriya, P. K.; Singh, R. G.; Pippel, E.

    2014-04-14

    Softening and stiffening of phonons in rutile titanium dioxide films are investigated by in situ micro-Raman studies during energetic ion irradiation. The in situ study minimized other possible mechanisms of phonon dynamics. Initial softening and broadening of Raman shift are attributed to the phonon confinement by structural defects and loss of stoichiometry. The stiffening of A{sub 1g} mode is ascribed to large distortion of TiO{sub 6} octahedra under the influence of lattice strain in the (110) plane, which gives rise to lengthening of equatorial Ti-O bond and shortening of apical Ti-O bond. The shortening of apical Ti-O bond induces stiffening of A{sub 1g} mode in the framework of the bond-order-length-strength correlation mechanism.

  1. XANES and micro-Raman spectroscopy study of the barium titanosilicates BaTiSi2O7 and BaTiSi4O11

    NASA Astrophysics Data System (ADS)

    Viani, A.; Pollastri, S.; Macova, P.; Palermo, A.; Peréz-Estébanez, M.; Gualtieri, A. F.

    2016-04-01

    The coordination environment around Ti4+ in the photoluminescent compound BaTiSi2O7 and in BaTiSi4O11 was investigated with X-ray absorption near-edge structure spectroscopy and micro-Raman spectroscopy. The presence of VTi in TiO5 pyramidal units with one short Ti-O bond involving the apical oxygen was detected in both compounds. Interpretation of the vibrational signal from the silicate framework suggested that BaTiSi4O11 is a metasilicate containing building units of SiO4 tetrahedra, which are larger than in other barium titanosilicates. These results confirmed the same structural environment of Ti4+ as recently disclosed by structure refinement of BaTiSi2O7 and provided new insights into the unknown structure of BaTiSi4O11 in the light of the study of its physical properties as potential functional material.

  2. Understanding the organo-carbonate associations in carbonaceous chondrites with the use of micro-Raman analysis

    NASA Astrophysics Data System (ADS)

    Chan, Q. H. S.; Zolensky, M. E.

    2015-10-01

    Carbonates can potentially provide sites for organic materials to accrue and develop into complex macromolecules. This study examines the organics associated with carbonates in carbonaceous chondrites using μ-Raman imaging.

  3. Integrated archeomagnetic and micro-Raman spectroscopy study of pre-Columbian ceramics from the Mesoamerican formative village of Cuanalan, Teotihuacan Valley, Mexico

    NASA Astrophysics Data System (ADS)

    Rodriguez Ceja, Maria; Goguitchaichvili, Avto; Morales, Juan; Ostrooumov, Mikhail; Manzanilla, Linda R.; Aguilar Reyes, Bertha; Urrutia-Fucugauchi, Jaime

    2009-04-01

    We report a detailed archeomagnetic and micro-Raman spectroscopy investigation on pre-Columbian pottery fragments from Cuanalan (a formative village in the valley of Teotihuacan, central Mexico). Available radiocarbon ages range from 2320 ± 80 to 2060 ± 90 B.P. Continuous low-field susceptibility versus temperature curves performed in air indicate Ti-poor titanomagnetites as magnetization carriers. Few samples, however, show two ferrimagnetic phases with Curie temperatures compatible with both Ti-poor and Ti-rich titanomagnetites. Hysteresis parameter ratios fall essentially in the pseudosingle-domain region, which may indicate a mixture of multidomain and a significant amount of single-domain grains. Mineralogical composition of the Teotihuacan ceramics has been investigated using micro-Raman spectroscopy. Samples are characterized by highly heterogeneous body matrix mineralogy due to the presence of a large variety of minerals with several mineralogical phases. Observed titanomagnetite and magnetite bands shift toward higher wave numbers, confirming a reducing atmosphere and a relatively high temperature (about 800-900°C) during the ceramic production. This definitively indicates the thermoremanent origin of magnetic magnetization. Archeointensity values have been determined from 7 pottery fragments (47 samples) out of 10 (70 samples) analyzed. Anisotropy of thermoremanent magnetization and the cooling rate effect upon thermoremanent magnetization intensity acquisition have been investigated in all the samples. The mean archeointensity values obtained in this study range from 24.2 ± 3.2 to 40.0 ± 1.7 μT, and corresponding virtual axial dipole moments range from 4.8 ± 0.6 to 8.0 ± 0.4 (1022 A m2). This corresponds to a mean virtual dipole moment value of 5.9 ± 1.1 × 1022 A m2, which is lower than the present-day field strength and the predicted values by global models and the latest data compilation. However, our data agree well with currently available

  4. High Pressure in situ Micro-Raman Spectroscopy of Ge-Sn System Synthesized in a Laser Heated Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Sorb, Y. A.; Subramanian, N.; Ravindran, T. R.; Sahu, P. Ch.

    2011-07-01

    GexSn1-x has been predicted to be a direct band-gap semiconductor, but attempts to synthesize this in bulk form by conventional synthesis methods have not been successful on account of the poor solubility of Sn in Ge. In this work, laser heated diamond anvil cell (LHDAC) technique has been employed to explore formation of bulk GexSn1-x (x = 0.7) at varying pressures and temperatures. At ˜8 GPa, in situ micro-Raman spectroscopy done on several regions of temperature quenched samples laser heated up to ˜2000 K reveals vanishing of the intense Ge TO(Γ) phonon at ˜326 cm-1 and appearance of a softer mode, concurrent with appearance of a new high intensity Raman mode at ˜660 cm-1. These indicate dilation of the Ge-Ge bond by virtue of significant miscibility of βSn at these high P-T conditions and hints at formation of new stiff Ge-Sn bonds.

  5. Influence of curvature strain and Van der Waals force on the inter-layer vibration mode of WS2 nanotubes: A confocal micro-Raman spectroscopic study.

    PubMed

    Wang, Xiao Hu; Zheng, Chang Cheng; Ning, Ji Qiang

    2016-01-01

    Transition-metal dichalcogenides (TMDs) nanostructures including nanotubes and monolayers have attracted great interests in materials science, chemistry to condensed matter physics. We present an interesting study of the vibration modes in multi-walled tungsten sulfide (WS2) nanotubes prepared via sulfurizing tungsten oxide (WO3) nanowires which are investigated by confocal micro-Raman spectroscopy. The inter-layer vibration mode of WS2 nanotubes, A1g, is found to be sensitive to the diameter and curvature strain, while the in-plane vibration mode, E(1)2g, is not. A1g mode frequency shows a redshift by 2.5 cm(-1) for the multi-layered nanotubes with small outer-diameters, which is an outcome of the competition between the Van der Waals force stiffening and the curvature strain softening. We also show that the Raman peak intensity ratio is significantly different between the 1-2 wall layered nanotubes and monolayer flat sheets. PMID:27620879

  6. Mesomorphic, micro-Raman and DFT studies of new calamitic liquid crystals; methyl 4-[4-(4-alkoxy benzoyloxy)benzylideneamino]benzoates

    NASA Astrophysics Data System (ADS)

    Nandi, Rajib; Singh, Hemant Kumar; Singh, Sachin Kumar; Singh, Bachcha; Singh, Ranjan K.

    2014-07-01

    The mesomorphic properties of newly synthesized homologous series of calamitic liquid crystals; methyl 4-[4-(4-alkoxy benzoyloxy)benzylideneamino]benzoates, H2n+1CnOC6H4COOC6H4C(H)dbnd N C6H4COOCH3; n = 6, 8, 10, 12, 14, 16 (MABBAB-n) containing ester and Schiff base groups as linker have been studied by temperature dependent micro-Raman study, differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). All members of this series exhibit enantiotropic smectic A (SmA) mesophase with oily streak and focal conic textures. Analyses of Raman marker bands of phenyl rings, Schiff base and ester groups of MABBAB-10 confirm the phase transitions. The Raman study also gives an evidence of breaking of weak intermolecular hydrogen bonds associated with ester groups and formation of new hydrogen bonds through Cdbnd N bond at Cr → SmA phase transition. The monomer and dimer were optimized and vibrational assignment of MABBAB-10 was also done with density functional theoretical (DFT) technique to understand the experimental results.

  7. Length-Scale-Dependent Phase Transformation of LiFePO4 : An In situ and Operando Study Using Micro-Raman Spectroscopy and XRD.

    PubMed

    Siddique, N A; Salehi, Amir; Wei, Zi; Liu, Dong; Sajjad, Syed D; Liu, Fuqiang

    2015-08-01

    The charge and discharge of lithium ion batteries are often accompanied by electrochemically driven phase-transformation processes. In this work, two in situ and operando methods, that is, micro-Raman spectroscopy and X-ray diffraction (XRD), have been combined to study the phase-transformation process in LiFePO4 at two distinct length scales, namely, particle-level scale (∼1 μm) and macroscopic scale (∼several cm). In situ Raman studies revealed a discrete mode of phase transformation at the particle level. Besides, the preferred electrochemical transport network, particularly the carbon content, was found to govern the sequence of phase transformation among particles. In contrast, at the macroscopic level, studies conducted at four different discharge rates showed a continuous but delayed phase transformation. These findings uncovered the intricate phase transformation in LiFePO4 and potentially offer valuable insights into optimizing the length-scale-dependent properties of battery materials. PMID:26073651

  8. Enhanced Light Scattering of the Forbidden longitudinal Optical Phonon Mode Studied by Micro-Raman Spectroscopy on Single InN nanowires

    SciTech Connect

    Sutter, E.; Schafer-Nolte, E.O.; Stoica T.; Gotschke, T.; Limbach, F.A.; Sutter, P.; Grutzmacher, D.; Calarco, R.

    2010-08-06

    In the literature, there are controversies on the interpretation of the appearance in InN Raman spectra of a strong scattering peak in the energy region of the unscreened longitudinal optical (LO) phonons, although a shift caused by the phonon-plasmon interaction is expected for the high conductance observed in this material. Most measurements on light scattering are performed on ensembles of InN nanowires (NWs). However, it is important to investigate the behavior of individual nanowires and here we report on micro-Raman measurements on single nanowires. When changing the polarization direction of the incident light from parallel to perpendicular to the wire, the expected reduction of the Raman scattering was observed for transversal optical (TO) and E2 phonon scattering modes, while a strong symmetry-forbidden LO mode was observed independently on the laser polarization direction. Single Mg- and Si-doped crystalline InN nanowires were also investigated. Magnesium doping results in a sharpening of the Raman peaks, while silicon doping leads to an asymmetric broadening of the LO peak. The results can be explained based on the influence of the high electron concentration with a strong contribution of the surface accumulation layer and the associated internal electric field.

  9. Near infrared excited micro-Raman spectra of 4:1 methanol-ethanol mixture and ruby fluorescence at high pressure

    NASA Astrophysics Data System (ADS)

    Wang, X. B.; Shen, Z. X.; Tang, S. H.; Kuok, M. H.

    1999-06-01

    Near infrared (NIR) lasers, as a new excitation source for Raman spectroscopy, has shown its unique advantages and is being increasingly used for some special samples, such as those emitting strong fluorescence in the visible region. This article focuses on some issues related to high-pressure micro-Raman spectroscopy using NIR excitation source. The Raman spectra of 4:1 methanol-ethanol mixture (4:1 M-E) show a linear variation in both Raman shifts and linewidths under pressure up to 18 GPa. This result is useful in distinguishing Raman scattering of samples from that of the alcohol mixture, an extensively used pressure-transmitting medium. The R1 fluorescence in the red region induced by two-photon absorption of the NIR laser is strong enough to be used as pressure scale. The frequency and line width of the R1 lines are very sensitive to pressure change and the glass transition of the pressure medium. Our results manifest that it is reliable and convenient to use NIR induced two-photon excited fluorescence of ruby for both pressure calibration and distribution of pressure in the 4:1 M-E pressure transmitting medium.

  10. Geochemistry of the Medieval Climate Anomaly varve sequence in Deep Inlet, Alaska, using core-scanning XRF, synchrotron micro-XRF and XANES spectroscopy, and micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Addison, J. A.; Hayes, S. M.; Sliwinski, M. G.; Routson, C.; Foster, A. L.

    2013-12-01

    The seasonal time resolution preserved in varved sediments make them critical archives of paleoclimate records. Our research group presents new geochemical data from a late Holocene varve sequence recovered from EW0408-44JC in Deep Inlet, an anoxic fjord in Southeast Alaska, with a particular focus on those varves deposited during the Medieval Climate Anomaly (~AD 1000) which is considered to be drier than at present in the Gulf of Alaska region. We utilize a combination of techniques: [1] scanning X-ray fluorescence (XRF) analysis of an 18-m-long split sediment core surface measured at 200-micron sampling resolution; [2] synchrotron-radiation micro-XRF (SR-μ-XRF) mapping of epoxy-impregnated thin sections at 6-to-50 micron spatial scales; [3] X-ray absorption near-edge spectroscopy (XANES) for Fe speciation; and [4] micro-Raman spectroscopy to determine varve mineralogy. Using these complementary techniques, we seek to determine if total iron concentration in Deep Inlet sediments can be used as a robust proxy for terrestrial erosion, and by inference, local precipitation and fluvial discharge. Our scanning XRF results show that total Fe concentration maxima tend to be co-located with dark-colored detrital mineral-rich sublaminae and turbidites, but there are several instances where this relationship is inconsistent. Thin-section SR-μ-XRF analysis of the same intervals reveal that high Fe concentrations are associated with detrital sublaminae, but Fe XANES reveal complex speciation in these fjord sediments, including sulfides (FeII), oxides and oxyhydroxides (FeIII), and mixed FeII/FeIII mineral phases. These diverse data imply a complex Fe cycle in Deep Inlet, comprising sources of Fe that likely include both detrital oxides and authigenic sulfides. Taken together, these data indicate caution is necessary in using total Fe concentrations as a proxy for paleoprecipitation reconstructions at this site. Studies of other redox-sensitive elements are underway (e

  11. Micro-Raman and micro-infrared spectroscopic studies of Pb- and Au-irradiated ZrSiO4: Optical properties, structural damage, and amorphization

    SciTech Connect

    Zhang, Ming; Boatner, Lynn A; Salje, Ekhard K.H.; Ewing, Rodney C.; Daniel, Philippe; Weber, William J.; Zhang, Yanwen; Farnan, Ian

    2008-01-01

    The optical properties of damaged periodic and aperiodic domains created by Pb+ 280 keV and Au4+ 10 MeV implantation of zircon were studied using micro-infrared IR and micro-Raman spectroscopy. The Pb+ and Au4+ irradiations caused a dramatic decrease in the IR reflectivity similar to that observed for metamict natural zircon. The irradiation with 10 MeV Au4+ ions to fluences of 11015 Au4+ ions/cm2 also results in the formation of an amorphized phase similar to that observed in metamict zircon. These results show that high-energy, heavy-ion irradiations provide a good simulation of the ballistic effects of the recoil nucleus of an alpha-decay event and, in both cases, the result is the creation of aperiodic domains. Additional IR and Raman features were recorded in samples irradiated with 280 keV Pb+ ions to fluences of 11014 and 1 1015 Pb+ ions/cm2, indicating the formation of an irradiation-induced additional phases. The frequencies of the features are consistent with lead silicates, ZrO2, and SiO2. The results show that spectral features of the Au4+- and Pb+-irradiated zircon are different from those of quenched ZrSiO4 melts, and the finding further confirms that the amorphous state produced by high-energy ion irradiations is structurally different from the glassy state that results from quenching a high temperature melt. In contrast to significant changes in the frequency and width of the Raman 3 band observed in metamict zircon, the Pb+ and Au4+ irradiations do not cause similar variations, indicating that the remaining zircon crystalline domains in irradiated samples have a crystalline structure with fewer defects than those of metamict zircon.

  12. Identification of antibody isotypes in biological fluids by means of micro-Raman spectroscopy and chemometric methods

    NASA Astrophysics Data System (ADS)

    Araujo-Andrade, C.; Pichardo-Molina, J. L.; Barbosa-Sabanero, G.; Frausto-Reyes, C.

    2008-02-01

    Clinical diagnosis of infections, generally are realized by serological methods, which identifies the antibodies presents in serum or tissue fluids of the patient. Antibodies are proteins present in our bodies that aid in the elimination of pathogens or antigens. Identification of antibodies isotypes is important because can help to predict when and whether patients will recover from infections and are commonly diagnosed by means of indirect methods such as serological test. In the other hand, the majority of these methods requires specific kits for the analysis, special sample preparation, chemical reagents, expensive equipment and require long time for getting results. In this work we show the feasibility to discriminate antibody isotypes in biological fluids like human colostrum by means of Raman spectroscopy and chemometrics. Spectra were obtained using an excitation wavelength of 514 nm over dried samples of human colostrum labeled previously as positives to specific IgG and IgM antibodies against Toxoplasma Gondii by means of ELISA test. Partial least square-discriminant analysis (PLS-DA) was used to discriminate among antibody isotypes by use second derivative of Raman spectra of colostrum samples.

  13. Vibrational Properties of Zr(Hf)B2-SiC UHTC Composites by Micro-Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Donohue, M.; Carpenter, C.; Orlovskaya, N.

    Development and characterization of novel materials that are lightweight, possess high mechanical properties, can withstand high temperatures, and provide superior thermal properties are crucial to meet the future demands of Air Force, Army, Navy, Missile Defense Agency (MDA), and other military and space agencies. Materials for such applications (hypersonic air-breathing vehicles, including Single-To-Orbit vehicles and Two-Stage-To-Orbit aerospace planes, fully reusable space transport vehicles, hypersonic cruise missiles) experience severe aero-thermal loads with nose-cone and nozzle temperatures in excess of 2,000°F and 4,000°F, respectively. High G acceleration is also a problem. Even the most advanced materials, such as Ti, Inconel X, carbon-carbon, and silicon carbide based composites cannot withstand the excessive heat generated, especially during re-entry, and they cannot meet the guidelines for future high performance aircrafts, kinetic energy interceptors and reusable space planes. Thus, the demand for low-cost, light weight high temperature materials for thermal protection systems (TPS) is expected to be on the significant rise in the near future.

  14. Rapid in situ detection of street samples of drugs of abuse on textile substrates using microRaman spectroscopy

    NASA Astrophysics Data System (ADS)

    Ali, Esam M. A.; Edwards, Howell G. M.; Scowen, Ian J.

    2011-10-01

    Trace amounts of street samples of cocaine hydrochloride and N-methyl-3,4-methylenedioxy-amphetamine (MDMA) on natural and synthetic textiles were successfully detected in situ using confocal Raman microscopy. The presence of some excipient bands in the spectra of the drugs did not prevent the unambiguous identification of the drugs. Raman spectra of the drugs were readily obtained without significant interference from the fibre substrates. Interfering bands arising from the fibre natural or synthetic polymer structure and/or dye molecules did not overlap with the characteristic Raman bands of the drugs. If needed, interfering bands could be successfully removed by spectral subtraction. Also, Raman spectra could be acquired from drug particles trapped between the fibres of highly fluorescent textile specimens. The total acquisition time of the spectra of the drug particles was 90 s accomplished non-destructively and without detachment from their substrates. Sample preparation was not required and spectra of the drugs could be obtained non-invasively preserving the integrity of the evidential material for further analysis.

  15. Occurrence and distribution of ``moganite'' in agate/chalcedony: a combined micro-Raman, Rietveld, and cathodoluminescence study

    NASA Astrophysics Data System (ADS)

    Götze, Jens; Nasdala, Lutz; Kleeberg, Reinhard; Wenzel, Marita

    Agate/chalcedony samples of different origin were investigated by performing Raman, X-ray diffraction (using Rietveld refinement), and cathodoluminescence measurements. These analyses were performed to measure the content and spatial distribution of the silica polymorph moganite, which is considered to represent periodic Brazil-law twinning of α-quartz at the unit-cell scale in agate/chalcedonies. Homogeneous standard samples including the nearly α-quartz free moganite type material from Gran Canaria were analysed in order to compare results of the X-ray diffractometry and Raman spectroscopy techniques and to provide a calibration curve for the Raman results. However, due to the different length scales analysed by the two techniques, the ``moganite content'' in microcrystalline SiO2 samples measured by Raman spectroscopy (short-range order) was found to be considerably higher than the ``moganite content'' measured by X-ray diffractometry (long-range order). The difference is explained by the presence of moganite nanocrystals, nano-range moganite lamellae, and single Brazil-law twin-planes that are detected by vibrational spectroscopy but that are not large enough (in the sense of coherently scattering lattice domains) to be detected by X-ray diffractometry. High resolution Raman analysis provides a measure of the moganite content and its spatial variation in microcrystalline silica samples with a lateral resolution in the μm-range. Variations in the moganite-to-quartz ratio are revealed by varying intensity ratios of the main symmetric stretching-bending vibrations (A1 modes) of α-quartz (465cm-1) and moganite (502cm-1), respectively. Traces of Raman microprobe analyses perpendicular to the rhythmic zoning of agates revealed that the moganite-to-quartz ratio is often not uniform but shows a cyclic pattern that correlates with the observed cathodoluminescence pattern (colour and intensity). Data obtained from an agate sample from a fluorite deposit near Okorusu

  16. Raman-spectroscopy-based biosensing for applications in ophthalmology

    NASA Astrophysics Data System (ADS)

    Rusciano, Giulia; Capriglione, Paola; Pesce, Giuseppe; Zito, Gianluigi; Del Prete, Antonio; Cennamo, Giovanni; Sasso, Antonio

    2013-05-01

    Cell-based biosensors rely on the detection and identification of single cells as well as monitoring of changes induced by interaction with drugs and/or toxic agents. Raman spectroscopy is a powerful tool to reach this goal, being non-destructive analytical technique, allowing also measurements of samples in aqueous environment. In addition, micro-Raman measurements do not require preliminary sample preparation (as in fluorescence spectroscopy), show a finger-print spectral response, allow a spatial resolution below typical cell sizes, and are relatively fast (few s or even less). All these properties make micro-Raman technique particularly promising for high-throughput on-line analysis integrated in lab-on-a-chip devices. Herein, we demonstrate some applications of Raman analysis in ophthalmology. In particular, we demonstrate that Raman analysis can provide useful information for the therapeutic treatment of keratitis caused by Acanthamoeba Castellanii (A.), an opportunistic protozoan that is widely distributed in the environment and is known to produce blinding keratitis and fatal encephalitis. In particular, by combining Raman analysis with Principal Component Analysis (PCA), we have demonstrated that is possible to distinguish between live and dead cells, enabling, therefore to establish the effectiveness of therapeutic strategies to vanquish the protozoa. As final step, we have analyzed the presence of biochemical differences in the conjunctival epithelial tissues of patients affected by keratitis with respect to healthy people. As a matter of facts, it is possible to speculate some biochemical alterations of the epithelial tissues, rendering more favorable the binding of the protozoan. The epithelial cells were obtained by impression cytology from eyes of both healthy and keratitis-affected individuals. All the samples were analyzed by Raman spectroscopy within a few hours from cells removal from eyes. The results of this analysis are discussed.

  17. Micro-Raman observation on the H2PO4- association structures in a supersaturated droplet of potassium dihydrogen phosphate (KH2PO4)

    NASA Astrophysics Data System (ADS)

    Syed, Kamran Ajmal; Pang, Shu-Feng; Zhang, Yun; Zhang, Yun-Hong

    2013-01-01

    The efflorescence of an individual KH2PO4 droplet on Teflon substrate was investigated by micro-Raman spectroscopy. With the decrease of relative humidity (RH) from 98.0% to 73.0%, the KH2PO4 droplet lost water gradually and entered into supersaturated state, which was reflected by the area ratio between the water stretching band to the sum of νs-PO2 and νs-P(OH)2 bands of the H2PO4- (A_{H_2 O} /(A_{(ν _s -PO_2 } {+ A}_{ν _s -P(OH)_2 {)}} {)}). In 1.0 mol l-1 KH2PO4 solution, the νs-P(OH)2 and νs-PO2 bands appeared at 877 and 1077 cm-1. In the KH2PO4 droplet, the two bands shifted to 894 and 1039 cm-1 at 98.0% RH, to 899 and 1031 cm-1 at 89.6% RH, and then to 904 and 997 cm-1 at 73.0% RH. Moreover, the aggregation process between the H2PO4- ions was observed from the spectral characteristic of the νs-P(OH)2 band in the concentration process, including the transitions of the H2PO4- ions from monomer in bulk solutions (0.5-1.0 mol l-1) to possible dimers at 98.0% RH and then further to oligomers in the droplet with the RH decrease, which were indicated by the blueshift of the νs-P(OH)2 band and its full width at half-height as a function of the RH. When the RH reached at 72.0%, the anhydrous crystal was obtained. A strong peak appeared at 928 cm-1, implying that the four oxygen atoms of the H2PO4- were all hydrogen bonding through the bridge hydrogen atoms to get the extensive hydrogen-bonded network structure of the H2PO4- association, leading to the symmetric increase of the H2PO4- ion from C2v in dilute solution to quasi-Td in the anhydrous crystal.

  18. Micro-Raman and micro-infrared spectroscopic studies of Pb- and Au-irradiated ZrSiO{sub 4}: Optical properties, structural damage, and amorphization

    SciTech Connect

    Zhang Ming; Salje, Ekhard K. H.; Farnan, Ian; Boatner, Lynn A.; Ewing, Rodney C.; Daniel, Philippe; Weber, William J.; Zhang Yanwen

    2008-04-01

    The optical properties of damaged periodic and aperiodic domains created by Pb{sup +} (280 keV) and Au{sup 4+} (10 MeV) implantation of zircon were studied using micro-infrared (IR) and micro-Raman spectroscopy. The Pb{sup +} and Au{sup 4+} irradiations caused a dramatic decrease in the IR reflectivity similar to that observed for metamict natural zircon. The irradiation with 10 MeV Au{sup 4+} ions (to fluences of 1x10{sup 15} Au{sup 4+} ions/cm{sup 2}) also results in the formation of an amorphized phase similar to that observed in metamict zircon. These results show that high-energy, heavy-ion irradiations provide a good simulation of the ballistic effects of the recoil nucleus of an alpha-decay event and, in both cases, the result is the creation of aperiodic domains. Additional IR and Raman features were recorded in samples irradiated with 280 keV Pb{sup +} ions (to fluences of 1x10{sup 14} and 1x10{sup 15} Pb{sup +} ions/cm{sup 2}), indicating the formation of an irradiation-induced additional phase(s). The frequencies of the features are consistent with lead silicates, ZrO{sub 2}, and SiO{sub 2}. The results show that spectral features of the Au{sup 4+}- and Pb{sup +}-irradiated zircon are different from those of quenched ZrSiO{sub 4} melts, and the finding further confirms that the amorphous state produced by high-energy ion irradiations is structurally different from the glassy state that results from quenching a high temperature melt. In contrast to significant changes in the frequency and width of the Raman {nu}{sub 3} band observed in metamict zircon, the Pb{sup +} and Au{sup 4+} irradiations do not cause similar variations, indicating that the remaining zircon crystalline domains in irradiated samples have a crystalline structure with fewer defects than those of metamict zircon.

  19. Micro-Raman and Micro-Infrared Spectroscopic Studies of Pb- and Au-Irradiated ZrSiO4. Optical Properties, Structural Damage and Amorphization

    SciTech Connect

    Zhang, Ming; Boatner, Lynn A.; Salje, Ekhard; Ewing, Rodney C.; Daniel, Philippe; Weber, William J; Zhang, Yanwen; Farnan, Ian E.

    2008-04-22

    The optical properties of damaged, periodic and aperiodic domains created by Pb+ (280 keV) and Au4+ (10 MeV) implantation of zircon were studied using micro-infrared (IR) and micro-Raman spectroscopy. The Pb+ and Au4+ irradiations caused a dramatic decrease in the IR reflectivity similar to that observed for metamict natural zircon. The irradiation with 10 MeV Au4+ ions (to fluences of 1x1015 Au4+ ions/cm2) also results in the formation of an amorphized phase similar to that observed in metamict zircon. These results show that high-energy, heavy-ion irradiations provide a good simulation of the ballistic effects of the recoil nucleus of an alpha-decay event, and in both cases, the result is the creation of aperiodic domains. Additional IR and Raman features were recorded in samples irradiated with 280 keV Pb+ ions (to fluences of 1x1014 and 1x1015 Pb+ ions/cm2), indicating the formation of an irradiation-induced new phase(s). The frequencies of the features are consistent with lead silicates, ZrO2 and SiO2. The results show that spectral features of the Au4+ and Pb+ irradiated zircon are different from those of quenched ZrSiO4 melts, and the finding further confirms that the amorphous state produced by high-energy ion irradiations is structurally different from the glassy state that results from quenching a high temperature melt. In contrast to significant changes in the frequency and width of the Raman v3 band observed in metamict zircon, the Pb+ and Au4+ irradiations do not cause similar variations, indicating that the remaining zircon crystalline domains in irradiated samples have a crystalline structure with fewer defects than those of metamict zircon.

  20. Study by micro-Raman spectroscopy of wall paints (external parts and cross-sections) from reales alcazares of Seville (Spain)

    NASA Astrophysics Data System (ADS)

    Perez-Rodriguez, José Luis; Centeno, Miguel Angel; Robador, María Dolores; Siguenza, Belinda; Durán, Adrián

    2013-04-01

    the other one by iron oxides. The green and white colours were constituted by atacamite and calcite, respectively. In addition lead white was detected in green colour. The white layers (plaster) located under the colour layers were constituted by calcite, quartz and feldspars. These data confirm the use of fresco technique. The study of the surface (external part) by micro-Raman spectroscopy limited the characterization of the pigments present in these wall pains, due to the presence of a layer of gypsum deposited on the surface. By other hand, the study by Raman spectroscopy of the cross-sections allowed the characterization of different pigments and support used in the manufacture of these wall paints.

  1. Application Power Signature Analysis

    SciTech Connect

    Hsu, Chung-Hsing; Combs, Jacob; Nazor, Jolie; Santiago, Fabian; Thysell, Rachelle; Rivoire, Suzanne; Poole, Stephen W

    2014-01-01

    The high-performance computing (HPC) community has been greatly concerned about energy efficiency. To address this concern, it is essential to understand and characterize the electrical loads of HPC applications. In this work, we study whether HPC applications can be distinguished by their power-consumption patterns using quantitative measures in an automatic manner. Using a collection of 88 power traces from 4 different systems, we find that basic statistical measures do a surprisingly good job of summarizing applications' distinctive power behavior. Moreover, this study opens up a new area of research in power-aware HPC that has a multitude of potential applications.

  2. Integrated analysis and applications

    NASA Technical Reports Server (NTRS)

    Hopkins, Dale A.

    1990-01-01

    An overview is presented of current research activities which, in a broad context, are focused on the development and verification of integrated structural analysis and optimal design capabilities for advanced aerospace propulsion and power systems. The overview encompasses a variety of subject areas including: (1) composite materials; (2) advanced structural analysis; (3) constitutive modeling; (4) computational simulation; (5) probabilistic analysis; and (6) multidisciplinary optimization. Typical results are presented which illustrate the benefit and utility of the emerging technologies as applied to propulsion and power system structures.

  3. IMS applications analysis

    SciTech Connect

    RODACY,PHILIP J.; REBER,STEPHEN D.; SIMONSON,ROBERT J.; HANCE,BRADLEY G.

    2000-03-01

    This report examines the market potential of a miniature, hand-held Ion Mobility Spectrometer. Military and civilian markets are discussed, as well as applications in a variety of diverse fields. The strengths and weaknesses of competing technologies are discussed. An extensive Ion Mobility Spectrometry (IMS) bibliography is included. The conclusions drawn from this study are: (1) There are a number of competing technologies that are capable of detecting explosives, drugs, biological, or chemical agents. The IMS system currently represents the best available compromise regarding sensitivity, specificity, and portability. (2) The military market is not as large as the commercial market, but the military services are more likely to invest R and D funds in the system. (3) Military applications should be addressed before commercial applications are addressed. (4) There is potentially a large commercial market for rugged, hand-held Ion Mobility Spectrometer systems. Commercial users typically do not invest R and D funds in this type of equipment rather, they wait for off-the-shelf availability.

  4. Applications of Raman spectroscopy in life science

    NASA Astrophysics Data System (ADS)

    Martin, Airton A.; T. Soto, Cláudio A.; Ali, Syed M.; Neto, Lázaro P. M.; Canevari, Renata A.; Pereira, Liliane; Fávero, Priscila P.

    2015-06-01

    Raman spectroscopy has been applied to the analysis of biological samples for the last 12 years providing detection of changes occurring at the molecular level during the pathological transformation of the tissue. The potential use of this technology in cancer diagnosis has shown encouraging results for the in vivo, real-time and minimally invasive diagnosis. Confocal Raman technics has also been successfully applied in the analysis of skin aging process providing new insights in this field. In this paper it is presented the latest biomedical applications of Raman spectroscopy in our laboratory. It is shown that Raman spectroscopy (RS) has been used for biochemical and molecular characterization of thyroid tissue by micro-Raman spectroscopy and gene expression analysis. This study aimed to improve the discrimination between different thyroid pathologies by Raman analysis. A total of 35 thyroid tissues samples including normal tissue (n=10), goiter (n=10), papillary (n=10) and follicular carcinomas (n=5) were analyzed. The confocal Raman spectroscopy allowed a maximum discrimination of 91.1% between normal and tumor tissues, 84.8% between benign and malignant pathologies and 84.6% among carcinomas analyzed. It will be also report the application of in vivo confocal Raman spectroscopy as an important sensor for detecting advanced glycation products (AGEs) on human skin.

  5. Tribological applications of surface analysis

    NASA Technical Reports Server (NTRS)

    Wheeler, D. R.

    1984-01-01

    For some years, surface analysis was used in fundamental studies of solid-solid contacts existing in tribological systems. Analysis was used to detect material transfer in sliding contacts. The effects of surface films on the adhesion of contacts was monitored. Finally electron spectroscopic analysis of interfaces has shed some light on the fundamental electronic nature of the interfacial bond. More recently, surface analysis was applied to many tribological engineering problems. In particular, identification of chemical films formed during the sliding contact of lubricated systems and study of the surface chemistry of lubricant additives were active areas of research. One or more of four properties of the analytical technique will be important in determining its utility. The four are: lateral resolution, specimen damage, depth resolution and the availability of chemical information. In each of the applications discussed here, the important factors are brought out.

  6. Planning applications in image analysis

    NASA Technical Reports Server (NTRS)

    Boddy, Mark; White, Jim; Goldman, Robert; Short, Nick, Jr.

    1994-01-01

    We describe two interim results from an ongoing effort to automate the acquisition, analysis, archiving, and distribution of satellite earth science data. Both results are applications of Artificial Intelligence planning research to the automatic generation of processing steps for image analysis tasks. First, we have constructed a linear conditional planner (CPed), used to generate conditional processing plans. Second, we have extended an existing hierarchical planning system to make use of durations, resources, and deadlines, thus supporting the automatic generation of processing steps in time and resource-constrained environments.

  7. Analysis methods for photovoltaic applications

    SciTech Connect

    1980-01-01

    Because photovoltaic power systems are being considered for an ever-widening range of applications, it is appropriate for system designers to have knowledge of and access to photovoltaic power systems simulation models and design tools. This brochure gives brief descriptions of a variety of such aids and was compiled after surveying both manufacturers and researchers. Services available through photovoltaic module manufacturers are outlined, and computer codes for systems analysis are briefly described. (WHK)

  8. Fringe analysis for automotive applications

    NASA Astrophysics Data System (ADS)

    Brown, Gordon M.

    The capabilities of Ford USA's Computer Aided Holometry (CAH) system for stepped phase interferometry are presented. Holographic test equipment and facilities are briefly reviewed. Fringe analysis algorithms and procedures for practical semi-automated processing of stepped phase interferograms of complex real life structures for quantitative measurement of deformation and shape are discussed. Several automative applications illustrating the fringe analysis technique are presented, including: (1) the use of CAH combined with Finite Element Analysis (FEA) methods to study frictional effects of the thermal insertion of a wrist pin into a connecting rod; (2) a study of engine deformation due to hydraulic loading of the cylinders; and (3) the computation of sound pressure from CAH measured vibration amplitude/phase and shape using the Rayleigh integral and SYSNOISE TM methods. In the past, holometry methods have been used primarily for problem solving in structures that were already in production, often where limited opportunities existed to make expensive modifications to existing tooling. Infrequently holometry was used by knowledgeable engineers to develop optimized components in the prototype stage even without the current CAE methods. The opportunity and challenge of our day is to closely couple CAE (FEM, EFA) methods and experimental methods (CAH, modal, etc.) to optimize structural performance in the upstream product development process where necessary tooling modifications can and will be made.

  9. Micro-Raman spectroscopy studies of changes in lipid composition in breast and prostate cancer cells treated with MPA and R1881 hormones

    NASA Astrophysics Data System (ADS)

    Potcoava, Mariana C.; Futia, Gregory L.; Aughenbaugh, Jessica; Schlaepfer, Isabel; Gibson, Emily A.

    2014-03-01

    Increasing interest in the role of lipids in cancer cell proliferation or resistance to drug therapies has motivated the need to develop better tools for cellular lipid analysis. Quantification of lipids in cells is typically done by destructive chromatography protocols that do not provide spatial information on lipid distribution and prevent dynamic live cell studies. Methods that allow the analysis of lipid content in live cells is therefore of great importance for research. Using Raman micro-spectroscopy we investigated whether the female hormone medroxyprogesterone acetate (MPA) and the synthetic androgen R1881 affect the lipid expression in breast (T47D) and prostate (LNCaP) cancer cells. Differences were noted in the spectral regions at 830-1800 cm-1 and 2800-3000 cm-1 when comparing different drug treatments. Significant changes were noticed for saturated (1063 - 1125 cm-1, 1295 cm-1 and 1439 cm-1), unsaturated (1262 cm-1 and 1656 cm-1, and 1720 - 1748 cm-1) chemical bonds, suggesting that the composition of the lipid droplets was changed by the hormone treatments. Also, significant differences were observed in the high frequency regions of lipids and proteins at 2851 cm-1 and around 2890 cm-1. Principal component analysis with Linear Discriminant Analysis (PCA-LDA) of the Raman spectra was able to differentiate between cancer cells that were treated with MPA, R1881 or vehicle (P < 0.05). Future work includes analysis to determine exact lipid composition and concentrations as well as development of clinical techniques to characterize differences in patient tumor lipid profiles to determine response to drug treatment and prognosis.

  10. Film analysis systems and applications

    SciTech Connect

    Yonekura, Y.; Brill, A.B.

    1981-01-01

    The different components that can be used in modern film analysis systems are reviewed. TV camera and charge-coupled device sensors coupled to computers provide low cost systems for applications such as those described. The autoradiography (ARG) method provides an important tool for medical research and is especially useful for the development of new radiopharmaceutical compounds. Biodistribution information is needed for estimation of radiation dose, and for interpretation of the significance of observed patterns. The need for such precise information is heightened when one seeks to elucidate physiological principles/factors in normal and experimental models of disease. The poor spatial resolution achieved with current PET-imaging systems limits the information on radioreceptor mapping, neutrotransmitter, and neuroleptic drug distribution that can be achieved from patient studies. The artful use of ARG in carefully-controlled animal studies will be required to provide the additional information needed to fully understand results obtained with this new important research tool. (ERB)

  11. Micro-IR reflectance spectra of the Paris carbonaceous chondrite coupled to ToF-SIMS and micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Baklouti, D.; Brunetto, R.; Noun, M.; Della Negra, S.; Pautrat, M.; Jamme, F.; Sandt, C.; Dumas, P.; Nsouli, B.; Roumie, M.; Merouane, S.; d'Hendecourt, L.; Dartois, E.

    2012-09-01

    We present the first micro-IR (1.5-15 μm) reflectance spectra of the Paris meteorite (a CM carbonaceous chondrite) [1,2,3]. Spectra are acquired at the SMIS (Spectroscopy and Microscopy in the Infrared using Synchrotron) beamline of the synchrotron SOLEIL (France), using a NicPlan microscope, coupled to a FTIR spectrometer operating in confocal reflection. A 500 μm wide area of a fragment (shown in Figure 1) of this meteorite was mapped with an IR spot ~20 μm. The region includes matrix and chondrules, and is chosen for its mineralogical and chemical diversity (essentially silicates, sulfates, carbonates, sulfides, and organic compounds). The IR identification of different mineral and carbonaceous components is supported by Raman micro-spectroscopy, performed at SOLEIL using a DXR Raman spectrometer from Thermo Fisher with a 532 nm exciting laser radiation, and a power on sample less than 0.3 mW (similarly to what described by [4]). The IR and Raman analysis is complemented by an elemental and structural analysis by ToF-SIMS (time of flight secondary ion mass spectrometry coupled to imaging), using a bismuth beam (25 keV and 1.3 pA) at LAEC-CNRS (Lebanon). The mass spectrometry coupled to imaging mode allows the identification of components and their location. It provides the opportunity to map at the same time the mineral and the organic components. To avoid any problem of pollution and contamination during the sample manipulation we performed, before the experiments, a surface cleaning by bismuth beam sputtering. Results will be discussed in the framework of the laboratory analyses in support of future samplereturn mission to carbon-rich asteroids. Emphasis will be given on the advantages of coupling a typical remote sensing tool (IR spectroscopy) to high spatial resolution techniques (Raman and ToF-SIMS) that would be performed on possible collected asteroidal samples.

  12. APPLICATION OF GAS CHROMATOGRAPHY IN FOOD ANALYSIS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gas chromatography (GC) is used widely in applications involving food analysis. Typical applications pertain to the quantitative and/or qualitative analysis of food composition, natural products, food additives, flavor and aroma components, a variety of transformation products, and contaminants suc...

  13. Applications analysis of high energy lasers

    NASA Technical Reports Server (NTRS)

    Arno, R. D.; Mackay, J. S.; Nishioka, K.

    1972-01-01

    An analysis and comparison of laser technology with competing technologies were made to determine possible laser applications. The analysis was undertaken as follows: (1) possible applications were listed and categorized; (2) required components were enumerated and the characteristics of these components were extrapolated; (3) complete system characteristics were calculated parametrically for selected applications using the postulated component characteristics; and (4) where possible and appropriate, comparisons were made with competing systems. It was found that any large scale replacement of existing systems and methods by lasers requires many technological advances in laser and associated systems. However, several applications appear feasible, such as low orbit drag make-up, orbit changing, communications, and illumination applications.

  14. Application of laser tweezers Raman spectroscopy techniques to the monitoring of single cell response to stimuli

    NASA Astrophysics Data System (ADS)

    Chan, James W.; Liu, Rui; Matthews, Dennis L.

    2012-06-01

    Laser tweezers Raman spectroscopy (LTRS) combines optical trapping with micro-Raman spectroscopy to enable label-free biochemical analysis of individual cells and small biological particles in suspension. The integration of the two technologies greatly simplifies the sample preparation and handling of suspension cells for spectroscopic analysis in physiologically meaningful conditions. In our group, LTRS has been used to study the effects of external perturbations, both chemical and mechanical, on the biochemistry of the cell. Single cell dynamics can be studied by performing longitudinal studies to continuously monitor the response of the cell as it interacts with its environment. The ability to carry out these measurements in-vitro makes LTRS an attractive tool for many biomedical applications. Here, we discuss the use of LTRS to study the response of cancer cells to chemotherapeutics and bacteria cells to antibiotics and show that the life cycle and apoptosis of the cells can be detected. These results show the promise of LTRS for drug discovery/screening, antibiotic susceptibility testing, and chemotherapy response monitoring applications. In separate experiments, we study the response of red blood cells to the mechanical forces imposed on the cell by the optical tweezers. A laser power dependent deoxygenation of the red blood cell in the single beam trap is reported. Normal, sickle cell, and fetal red blood cells have a different behavior that enables the discrimination of the cell types based on this mechanochemical response. These results show the potential utility of LTRS for diagnosing and studying red blood cell diseases.

  15. Small wind systems application analysis. Executive summary

    NASA Astrophysics Data System (ADS)

    1981-06-01

    The potential market for SWECS, or wind machines smaller than 100 kW for five selected applications was estimated. The goals of the study were to aid manufacturers in attaining financing by convincing venture capital investors of the potential of SWECS and to aid government planners in allocating R and D expenditures that will effectively advance SWECS commercialization. The five applications were selected through an initial screening and priority-ranking analysis. The year of analysis was 1985, but all dollar amounts, such as fuel costs, are expressed in 1980 dollars. The five SWECS applications investigated were farm residences, non-farm residences rural electric cooperatives, feed grinders, and remote communities.

  16. Failure environment analysis tool applications

    NASA Technical Reports Server (NTRS)

    Pack, Ginger L.; Wadsworth, David B.

    1993-01-01

    Understanding risks and avoiding failure are daily concerns for the women and men of NASA. Although NASA's mission propels us to push the limits of technology, and though the risks are considerable, the NASA community has instilled within, the determination to preserve the integrity of the systems upon which our mission and, our employees lives and well-being depend. One of the ways this is being done is by expanding and improving the tools used to perform risk assessment. The Failure Environment Analysis Tool (FEAT) was developed to help engineers and analysts more thoroughly and reliably conduct risk assessment and failure analysis. FEAT accomplishes this by providing answers to questions regarding what might have caused a particular failure; or, conversely, what effect the occurrence of a failure might have on an entire system. Additionally, FEAT can determine what common causes could have resulted in other combinations of failures. FEAT will even help determine the vulnerability of a system to failures, in light of reduced capability. FEAT also is useful in training personnel who must develop an understanding of particular systems. FEAT facilitates training on system behavior, by providing an automated environment in which to conduct 'what-if' evaluation. These types of analyses make FEAT a valuable tool for engineers and operations personnel in the design, analysis, and operation of NASA space systems.

  17. Failure environment analysis tool applications

    NASA Technical Reports Server (NTRS)

    Pack, Ginger L.; Wadsworth, David B.

    1994-01-01

    Understanding risks and avoiding failure are daily concerns for the women and men of NASA. Although NASA's mission propels us to push the limits of technology, and though the risks are considerable, the NASA community has instilled within it, the determination to preserve the integrity of the systems upon which our mission and, our employees lives and well-being depend. One of the ways this is being done is by expanding and improving the tools used to perform risk assessment. The Failure Environment Analysis Tool (FEAT) was developed to help engineers and analysts more thoroughly and reliably conduct risk assessment and failure analysis. FEAT accomplishes this by providing answers to questions regarding what might have caused a particular failure; or, conversely, what effect the occurrence of a failure might have on an entire system. Additionally, FEAT can determine what common causes could have resulted in other combinations of failures. FEAT will even help determine the vulnerability of a system to failures, in light of reduced capability. FEAT also is useful in training personnel who must develop an understanding of particular systems. FEAT facilitates training on system behavior, by providing an automated environment in which to conduct 'what-if' evaluation. These types of analyses make FEAT a valuable tool for engineers and operations personnel in the design, analysis, and operation of NASA space systems.

  18. Optical diagnostic techniques in tribological analysis: Applications to wear film characterization, solid lubricant chemical transition, and electrical sliding contacts

    NASA Astrophysics Data System (ADS)

    Windom, Bret C.

    Friction and wear have undisputedly huge macroscopic effects on the cost and lifetime of many mechanical systems. The cost to replace parts and the cost to overcome the energy losses associated with friction, although small in nature, can be enormous over long operating times. The understanding of wear and friction begins with the understanding of the physics and chemistry between the reacting surfaces on a microscopic level. Light as a diagnostic tool is a good candidate to perform the very sensitive microscopic measurements needed to help understand the fundamental science occurring in friction/wear systems. Light's small length scales provide the capabilities to characterize very local surface phenomena, including thin transfer films and surface chemical transitions. Light-based diagnostic techniques provide nearly instantaneous results, enabling one to make in situ/real time measurements which could be used to track wear events and associated chemical kinetics. In the present study, two optical diagnostic techniques were investigated for the analysis of tribological systems. The first technique employed was Raman spectroscopy. Raman spectroscopy was investigated as a possible means for in situ measurement of thin transfer films in order to track the wear kinetics and structural transitions of bulk polymers. A micro-Raman system was designed, built, and characterized to track fresh wear films created from a pin-on-disk tribometer. The system proved capable of characterizing and tracking wear film thicknesses of ˜2 mum and greater. In addition, the system provided results indicating structural changes in the wear film as compared to the bulk when sliding speeds were increased. The spectral changes due to the altering of molecular vibrations can be attributed to the increase in temperature during high sliding speeds. Raman spectroscopy was also used to characterize the oxidation of molybdenum disulphide, a solid lubricant used in many applications, including high

  19. Synthesis of carbon nanofibres from waste chicken fat for field electron emission applications

    SciTech Connect

    Suriani, A.B.; Dalila, A.R.; Mohamed, A.; Isa, I.M.; Kamari, A.; Hashim, N.; Soga, T.; Tanemura, M.

    2015-10-15

    Highlights: • Waste chicken fat is used as a starting material to produce CNFs via TCVD method. • High heating rate applied resulted in aggregation of catalyst particles. • Aggregated catalyst produced sea urchin-like CNFs with amorphous nature. • The as-grown CNFs presented a potential for field electron emission applications. - Abstract: Carbon nanofibres (CNFs) with sea urchin-like morphology were synthesised from waste chicken fat precursor via catalytic thermal chemical vapour deposition method at 750 °C. The CNFs showed amorphous structures under high-resolution transmission electron microscopy, micro-Raman spectroscopy and X-ray diffraction examination. X-ray photoelectron spectroscopy analysis confirmed that the core of the sea urchin-like CNFs was composed of Fe{sub 3}C formed within the first 20 min of synthesis time. The growth of amorphous CNFs from agglomerated Fe{sub 3}C particles was favourable due to the high heating rate applied during the synthesis. Field electron emission examination of the CNFs indicated turn-on and threshold field values of 5.4 and 6.6 V μm{sup −1} at current density of 1 and 10 μA cm{sup −2}, respectively. This study demonstrates that waste chicken fat, a low-cost and readily available resource, can be used as an inexpensive carbon source for the production of CNFs with a potential application in field electron emitters.

  20. Environmental applications of the particle analysis system

    SciTech Connect

    Moritz, E.J.; Hoffman, C.R.

    1993-09-28

    This study demonstrates the applicability of particle counting technology for analysis of various water treatment systems at the Rocky Flats Plant. The Particle Analysis System described in this study determined the water quality of samples from environmental remediation, stormwater treatment, and drinking water treatment operations. Samples were measured in either discrete or on-line mode. This data showed filtration efficiencies, particle counts, particle size distributions, and real-time treatment system performance. Particle counting proved more sensitive than the turbidimetric measurement technique commonly used by the water treatment industry. Particle counting is a two-dimensional measurement of counts and sizes, whereas turbidity is a one-dimensional measurement of water clarity. Samples showing identical turbidities could be distinguished easily with the Particle Analysis System. The Particle Analysis System proved to be an efficient and reliable water quality measurement tool, and it is applicable to a variety of water treatment systems at the Rocky Flats Plant.

  1. A forensic application of PIXE analysis

    NASA Astrophysics Data System (ADS)

    Kravchenko, I. I.; Dunnam, F. E.; Van Rinsvelt, H. A.; Warren, M. W.; Falsetti, A. B.

    2001-07-01

    PIXE measurements were performed on various calcareous materials including identified bone residues, human cremains, and samples of disputed origin. In a forensic application, the elemental analysis suggests that the origin of a sample suspectly classified as human cremains can tentatively be identified as a mixture of sandy soil and dolomitic limestone.

  2. Military housing foam application and analysis

    SciTech Connect

    Torres, J. J.

    2012-03-01

    Sandia and Forest City have established a Cooperative Research and Development Agreement (CRADA), the partnership provides a unique opportunity to take technology research and development from demonstration to application in sustainable communities. This project consists of two activities conducted in Hawaii that focus on performance, integration and application of energy saving technologies. Hawaii has many energy challenges, making this location an excellent testbed for these activities. Under this project, spray foam technology was applied at military housing on Oahu and the consumption data collected. A cost benefit and operational analysis of the foam was completed. The second phase of this project included design, integration, and analysis of photovoltaic systems at a military community on Oahu. This phase of the project was conducted as part of Forest City's second Solar America Showcase Award.

  3. Probabilistic structural analysis methods and applications

    NASA Technical Reports Server (NTRS)

    Cruse, T. A.; Wu, Y.-T.; Dias, B.; Rajagopal, K. R.

    1988-01-01

    An advanced algorithm for simulating the probabilistic distribution of structural responses due to statistical uncertainties in loads, geometry, material properties, and boundary conditions is reported. The method effectively combines an advanced algorithm for calculating probability levels for multivariate problems (fast probability integration) together with a general-purpose finite-element code for stress, vibration, and buckling analysis. Application is made to a space propulsion system turbine blade for which the geometry and material properties are treated as random variables.

  4. Error analysis of quartz crystal resonator applications

    SciTech Connect

    Lucklum, R.; Behling, C.; Hauptmann, P.; Cernosek, R.W.; Martin, S.J.

    1996-12-31

    Quartz crystal resonators in chemical sensing applications are usually configured as the frequency determining element of an electrical oscillator. By contrast, the shear modulus determination of a polymer coating needs a complete impedance analysis. The first part of this contribution reports the error made if common approximations are used to relate the frequency shift to the sorbed mass. In the second part the authors discuss different error sources in the procedure to determine shear parameters.

  5. Software applications for flux balance analysis.

    PubMed

    Lakshmanan, Meiyappan; Koh, Geoffrey; Chung, Bevan K S; Lee, Dong-Yup

    2014-01-01

    Flux balance analysis (FBA) is a widely used computational method for characterizing and engineering intrinsic cellular metabolism. The increasing number of its successful applications and growing popularity are possibly attributable to the availability of specific software tools for FBA. Each tool has its unique features and limitations with respect to operational environment, user-interface and supported analysis algorithms. Presented herein is an in-depth evaluation of currently available FBA applications, focusing mainly on usability, functionality, graphical representation and inter-operability. Overall, most of the applications are able to perform basic features of model creation and FBA simulation. COBRA toolbox, OptFlux and FASIMU are versatile to support advanced in silico algorithms to identify environmental and genetic targets for strain design. SurreyFBA, WEbcoli, Acorn, FAME, GEMSiRV and MetaFluxNet are the distinct tools which provide the user friendly interfaces in model handling. In terms of software architecture, FBA-SimVis and OptFlux have the flexible environments as they enable the plug-in/add-on feature to aid prospective functional extensions. Notably, an increasing trend towards the implementation of more tailored e-services such as central model repository and assistance to collaborative efforts was observed among the web-based applications with the help of advanced web-technologies. Furthermore, most recent applications such as the Model SEED, FAME, MetaFlux and MicrobesFlux have even included several routines to facilitate the reconstruction of genome-scale metabolic models. Finally, a brief discussion on the future directions of FBA applications was made for the benefit of potential tool developers. PMID:23131418

  6. INTERNAL HAZARDS ANALYSIS FOR LICENSE APPLICATION

    SciTech Connect

    R.J. Garrett

    2005-02-17

    The purpose of this internal hazards analysis is to identify and document the internal hazards and potential initiating events associated with preclosure operations of the repository at Yucca Mountain. Internal hazards are those hazards presented by the operation of the facility and by its associated processes that can potentially lead to a radioactive release or cause a radiological hazard. In contrast to external hazards, internal hazards do not involve natural phenomena and external man-made hazards. This internal hazards analysis was performed in support of the preclosure safety analysis and the License Application for the Yucca Mountain Project. The methodology for this analysis provides a systematic means to identify internal hazards and potential initiating events that may result in a radiological hazard or radiological release during the repository preclosure period. These hazards are documented in tables of potential internal hazards and potential initiating events (Section 6.6) for input to the repository event sequence categorization process. The results of this analysis will undergo further screening and analysis based on the criteria that apply to the performance of event sequence analyses for the repository preclosure period. The evolving design of the repository will be re-evaluated periodically to ensure that internal hazards that have not been previously evaluated are identified.

  7. Dynamic Analysis of Mobile Device Applications

    SciTech Connect

    Corey Thuen

    2013-01-01

    The On-Device Dynamic Analysis of Mobile Applications (ODAMA) project was started in an effort to protect mobile devices used in Industrial Control Systems (ICS) from cyber attack. Because mobile devices hide as much of the “computer” as possible, the user’s ability to assess the software running on their system is limited. The research team chose Google’s Android platform for this initial research because it is open source and it would give us freedom in our approach, including the ability to modify the mobile device’s operating system itself. The research team concluded that a Privileged Application was the right approach, and the result was ODAMA. This project is an important piece of the work to secure the expanding use of mobile devices with our nation’s critical infrastructure.

  8. Guidebook for analysis of tether applications

    NASA Technical Reports Server (NTRS)

    Carroll, J. A.

    1985-01-01

    This guidebook is intended as a tool to facilitate initial analyses of proposed tether applications in space. The guiding philosophy is that a brief analysis of all the common problem areas is far more useful than a detailed study in any one area. Such analyses can minimize the waste of resources on elegant but fatally flawed concepts, and can identify the areas where more effort is needed on concepts which do survive the initial analyses. The simplified formulas, approximations, and analytical tools included should be used only for preliminary analyses. For detailed analyses, the references with each topic and in the bibliography may be useful.

  9. Application of Electromigration Techniques in Environmental Analysis

    NASA Astrophysics Data System (ADS)

    Bald, Edward; Kubalczyk, Paweł; Studzińska, Sylwia; Dziubakiewicz, Ewelina; Buszewski, Bogusław

    Inherently trace-level concentration of pollutants in the environment, together with the complexity of sample matrices, place a strong demand on the detection capabilities of electromigration methods. Significant progress is continually being made, widening the applicability of these techniques, mostly capillary zone electrophoresis, micellar electrokinetic chromatography, and capillary electrochromatography, to the analysis of real-world environmental samples, including the concentration sensitivity and robustness of the developed analytical procedures. This chapter covers the recent major developments in the domain of capillary electrophoresis analysis of environmental samples for pesticides, polycyclic aromatic hydrocarbons, phenols, amines, carboxylic acids, explosives, pharmaceuticals, and ionic liquids. Emphasis is made on pre-capillary and on-capillary chromatography and electrophoresis-based concentration of analytes and detection improvement.

  10. Integrated FDIR Analysis Tool for Space Applications

    NASA Astrophysics Data System (ADS)

    Piras, Annamaria; Malucchi, Giovanni; Di Tommaso, Umberto

    2013-08-01

    The crucial role of health management in space applications has been the subject of many studies carried out by NASA and ESA and is held in high regard by Thales Alenia Space. The common objective is to improve reliability and availability of space systems. This paper will briefly illustrate the evolution of IDEHAS (IntegrateD Engineering Harness Avionics and Software), an advanced tool currently used in Thales Alenia Space - Italy in several space programs and recently enhanced to fully support FDIR (Fault Detection Isolation and Recovery) analysis. The FDIR analysis logic flow will be presented, emphasizing the improvements offered to Mission Support & Operations activities. Finally the benefits provided to the Company and a list of possible future enhancements will be given.

  11. Application of ultrasonics to chemical analysis

    SciTech Connect

    Chmilenko, F.A.; Baklanov, A.N.; Sidorova, L.P.; Piskun, Yu.M.

    1994-06-01

    Ultrasonics has found a wide utility in chemistry, making available energy densities of the order of 10{sup 3} to 10{sup 6} W/cm{sup 3}, which is 3-5 orders of magnitude greater than the energy densities used in some physical methods like radiolysis and photolysis. The paper overviews several techniques of ultrasound to chemical analysis with the greatest effect obtained by using a wide range of ultrasound frequencies. The methods described include: using different ultrasound properties like velocity of propagation, decay rate, acoustic resistance, and relaxational absorption as analytical signals; the use of sonoluminescence; applications for oxidation, coagulating, and dispersion by ultrasound methods; use of ultrasound for sample preparation; and the use of ultrasound for widening the scope of the atomic spectroscopy and electrochemcial methods of analysis.

  12. Residual energy applications program systems analysis report

    SciTech Connect

    Yngve, P.W.

    1980-10-01

    Current DOE plans call for building an Energy Applied Systems Test (EAST) Facility at the Savannah River Plant in close proximity to the 140 to 150/sup 0/F waste heat from one of several operating nuclear reactors. The waste water flow from each reactor, approximately 165,000 gpm, provides a unique opportunity to test the performance and operating characteristics of large-scale waste heat power generation and heat pump system concepts. This report provides a preliminary description of the potential end-use market, parametric data on heat pump and the power generation system technology, a preliminary listing of EAST Facility requirements, and an example of an integrated industrial park utilizing the technology to maximize economic pay back. The parametric heat pump analysis concluded that dual-fluid Rankine cycle heat pumps with capacities as high as 400 x 10/sup 6/ Btu/h, can utilize large sources of low temperature residual heat to provide 300/sup 0/F saturatd steam for an industrial park. The before tax return on investment for this concept is 36.2%. The analysis also concluded that smaller modular heat pumps could fulfill the same objective while sacrificing only a moderate rate of return. The parametric power generation analysis concluded that multi-pressure Rankine cycle systems not only are superior to single pressure systems, but can also be developed for large systems (approx. = 17 MW/sub e/). This same technology is applicable to smaller systems at the sacrifice of higher investment per unit output.

  13. Acceleration of Data Analysis Applications using GPUs

    NASA Astrophysics Data System (ADS)

    Fillmore, D.; Messmer, P.; Mullowney, P.; Amyx, K.

    2008-12-01

    The vast amount of data collected by present and future scientific instruments, sensors and numerical models requires a significant increase in computing power for analysis. In many cases, processing time on a single workstation becomes impractical. While clusters of commodity processors can be utilized to accelerate some of these tasks, the relatively high software development cost, as well as acquisition and operational costs, make them less attractive for broad use. Over the past few years, another class of architectures has gained some popularity, namely heterogeneous architectures, which consist of general purpose processors connected to specialized processors. One of the most prominent examples are Graphics Processing Units (GPUs), which offer a tremendous amount of floating-point processing power due to demand for high-quality graphics in the computer game market. However, in order to harness this processing power, software developers have to develop with a detailed understanding of the underlying hardware. This burden on the developer is often hardly justifiable considering the rapid evolution of the hardware. In this talk, we will introduce GPULib, an open source library that enables scientists to accelerate their data analysis tasks using the GPUs already installed in their system from within high-level languages like IDL or MATLAB, and present examples and possible speedup from real-world data analysis applications. This work is funded through NASA Phase II SBIR Grant NNG06CA13C.

  14. Effect of application mode on interfacial morphology and chemistry between dentin and self-etch adhesives

    PubMed Central

    Zhang, Ying; Wang, Yong

    2012-01-01

    Objective To investigate the influence of application mode on the interfacial morphology and chemistry between dentin and self-etch adhesives with different aggressiveness. Methods The occlusal one-third of the crown was removed from un-erupted human third molars, followed by abrading with 600 grit SiC under water. Rectangular dentin slabs were prepared by sectioning the tooth specimens perpendicular to the abraded surfaces. The obtained dentin slabs were treated with one of the two one-step self-etch adhesives: Adper Easy Bond (AEB, PH~2.5) and Adper Prompt L-Pop (APLP, PH~0.8) with (15s, active application) or without (15s, inactive application) agitation. The dentin slabs were fractured and the exposed adhesive/dentin (A/D) interfaces were examined with micro-Raman spectroscopy and scanning electron microscopy (SEM). Results The interfacial morphology, degree of dentin demineralization (DD) and degree of conversion (DC) of the strong self-etch adhesive APLP showed more significant dependence on the application mode than the mild AEB. APLP exhibited inferior bonding at the A/D interface if applied without agitation, evidenced by debonding from the dentin substrate. The DDs and DCs of the APLP with agitation were higher than those of without agitation in the interface, in contrast to the comparable DD and DC values of two AEB specimen groups with different application modes. Raman spectral analysis revealed the important role of chemical interaction between acid monomers of self-etch adhesives and dentin in the above observations. Conclusion The chemical interaction with dentin is especially important for improving the DC of the strong self-etching adhesive at the A/D interface. Agitation could benefit polymerization efficacy of the strong self-etch adhesive through enhancing the chemical interaction with tooth substrate. PMID:23153573

  15. Ion beam analysis in cultural heritage studies: Milestones and perspectives

    SciTech Connect

    Dran, Jean-Claude; Calligaro, Thomas

    2013-07-18

    For three decades, ion beam analysis (IBA) in external mode was considered as the best choice for the characterisation of cultural heritage materials, as it combines excellent analytical performance and non-invasive character. However, in recent years, other analytical techniques arose as serious competitors, such as those based on synchrotron radiation (X-ray absorption, fluorescence or diffraction) or those using portable instruments (XRF, micro-Raman). It is shown that nevertheless IBA remains unmatched thanks to two unique features, namely the analysis of light elements and the high-resolution 3D chemical imaging.

  16. Ion beam analysis in cultural heritage studies: Milestones and perspectives

    NASA Astrophysics Data System (ADS)

    Dran, Jean-Claude; Calligaro, Thomas

    2013-07-01

    For three decades, ion beam analysis (IBA) in external mode was considered as the best choice for the characterisation of cultural heritage materials, as it combines excellent analytical performance and non-invasive character. However, in recent years, other analytical techniques arose as serious competitors, such as those based on synchrotron radiation (X-ray absorption, fluorescence or diffraction) or those using portable instruments (XRF, micro-Raman). It is shown that nevertheless IBA remains unmatched thanks to two unique features, namely the analysis of light elements and the high-resolution 3D chemical imaging.

  17. The applicability and effectiveness of cluster analysis

    NASA Technical Reports Server (NTRS)

    Ingram, D. S.; Actkinson, A. L.

    1973-01-01

    An insight into the characteristics which determine the performance of a clustering algorithm is presented. In order for the techniques which are examined to accurately cluster data, two conditions must be simultaneously satisfied. First the data must have a particular structure, and second the parameters chosen for the clustering algorithm must be correct. By examining the structure of the data from the Cl flight line, it is clear that no single set of parameters can be used to accurately cluster all the different crops. The effectiveness of either a noniterative or iterative clustering algorithm to accurately cluster data representative of the Cl flight line is questionable. Thus extensive a prior knowledge is required in order to use cluster analysis in its present form for applications like assisting in the definition of field boundaries and evaluating the homogeneity of a field. New or modified techniques are necessary for clustering to be a reliable tool.

  18. Generic element processor (application to nonlinear analysis)

    NASA Technical Reports Server (NTRS)

    Stanley, Gary

    1989-01-01

    The focus here is on one aspect of the Computational Structural Mechanics (CSM) Testbed: finite element technology. The approach involves a Generic Element Processor: a command-driven, database-oriented software shell that facilitates introduction of new elements into the testbed. This shell features an element-independent corotational capability that upgrades linear elements to geometrically nonlinear analysis, and corrects the rigid-body errors that plague many contemporary plate and shell elements. Specific elements that have been implemented in the Testbed via this mechanism include the Assumed Natural-Coordinate Strain (ANS) shell elements, developed with Professor K. C. Park (University of Colorado, Boulder), a new class of curved hybrid shell elements, developed by Dr. David Kang of LPARL (formerly a student of Professor T. Pian), other shell and solid hybrid elements developed by NASA personnel, and recently a repackaged version of the workhorse shell element used in the traditional STAGS nonlinear shell analysis code. The presentation covers: (1) user and developer interfaces to the generic element processor, (2) an explanation of the built-in corotational option, (3) a description of some of the shell-elements currently implemented, and (4) application to sample nonlinear shell postbuckling problems.

  19. Femtosecond-laser direct writing in polymers and potential applications in microfluidics and memory devices

    NASA Astrophysics Data System (ADS)

    Kallepalli, Lakshmi Narayana Deepak; Soma, Venugopal Rao; Desai, Narayana Rao

    2012-07-01

    We have investigated femtosecond-laser-induced microstructures (on the surface and within the bulk), gratings, and craters in four different polymers: polymethyl methacrylate, polydimethylsiloxane, polystyrene, and polyvinyl alcohol. The structures were achieved using a Ti:sapphire laser delivering 100-fs pulses at 800 nm with a repetition rate of 1 kHz and a maximum pulse energy of 1 mJ. Local chemical modifications leading to the formation of optical centers and peroxide radicals were studied using ultraviolet-visible absorption and emission, confocal micro-Raman and electron spin resonance spectroscopic techniques. Potential applications of these structures in microfluidics, waveguides, and memory-based devices are demonstrated.

  20. Accelerating DNA analysis applications on GPU clusters

    SciTech Connect

    Tumeo, Antonino; Villa, Oreste

    2010-06-13

    DNA analysis is an emerging application of high performance bioinformatic. Modern sequencing machinery are able to provide, in few hours, large input streams of data which needs to be matched against exponentially growing databases known fragments. The ability to recognize these patterns effectively and fastly may allow extending the scale and the reach of the investigations performed by biology scientists. Aho-Corasick is an exact, multiple pattern matching algorithm often at the base of this application. High performance systems are a promising platform to accelerate this algorithm, which is computationally intensive but also inherently parallel. Nowadays, high performance systems also include heterogeneous processing elements, such as Graphic Processing Units (GPUs), to further accelerate parallel algorithms. Unfortunately, the Aho-Corasick algorithm exhibits large performance variabilities, depending on the size of the input streams, on the number of patterns to search and on the number of matches, and poses significant challenges on current high performance software and hardware implementations. An adequate mapping of the algorithm on the target architecture, coping with the limit of the underlining hardware, is required to reach the desired high throughputs. Load balancing also plays a crucial role when considering the limited bandwidth among the nodes of these systems. In this paper we present an efficient implementation of the Aho-Corasick algorithm for high performance clusters accelerated with GPUs. We discuss how we partitioned and adapted the algorithm to fit the Tesla C1060 GPU and then present a MPI based implementation for a heterogeneous high performance cluster. We compare this implementation to MPI and MPI with pthreads based implementations for a homogeneous cluster of x86 processors, discussing the stability vs. the performance and the scaling of the solutions, taking into consideration aspects such as the bandwidth among the different nodes.

  1. Sensitivity analysis and application in exploration geophysics

    NASA Astrophysics Data System (ADS)

    Tang, R.

    2013-12-01

    In exploration geophysics, the usual way of dealing with geophysical data is to form an Earth model describing underground structure in the area of investigation. The resolved model, however, is based on the inversion of survey data which is unavoidable contaminated by various noises and is sampled in a limited number of observation sites. Furthermore, due to the inherent non-unique weakness of inverse geophysical problem, the result is ambiguous. And it is not clear that which part of model features is well-resolved by the data. Therefore the interpretation of the result is intractable. We applied a sensitivity analysis to address this problem in magnetotelluric(MT). The sensitivity, also named Jacobian matrix or the sensitivity matrix, is comprised of the partial derivatives of the data with respect to the model parameters. In practical inversion, the matrix can be calculated by direct modeling of the theoretical response for the given model perturbation, or by the application of perturbation approach and reciprocity theory. We now acquired visualized sensitivity plot by calculating the sensitivity matrix and the solution is therefore under investigation that the less-resolved part is indicated and should not be considered in interpretation, while the well-resolved parameters can relatively be convincing. The sensitivity analysis is hereby a necessary and helpful tool for increasing the reliability of inverse models. Another main problem of exploration geophysics is about the design strategies of joint geophysical survey, i.e. gravity, magnetic & electromagnetic method. Since geophysical methods are based on the linear or nonlinear relationship between observed data and subsurface parameters, an appropriate design scheme which provides maximum information content within a restricted budget is quite difficult. Here we firstly studied sensitivity of different geophysical methods by mapping the spatial distribution of different survey sensitivity with respect to the

  2. Voxel-Based LIDAR Analysis and Applications

    NASA Astrophysics Data System (ADS)

    Hagstrom, Shea T.

    One of the greatest recent changes in the field of remote sensing is the addition of high-quality Light Detection and Ranging (LIDAR) instruments. In particular, the past few decades have been greatly beneficial to these systems because of increases in data collection speed and accuracy, as well as a reduction in the costs of components. These improvements allow modern airborne instruments to resolve sub-meter details, making them ideal for a wide variety of applications. Because LIDAR uses active illumination to capture 3D information, its output is fundamentally different from other modalities. Despite this difference, LIDAR datasets are often processed using methods appropriate for 2D images and that do not take advantage of its primary virtue of 3-dimensional data. It is this problem we explore by using volumetric voxel modeling. Voxel-based analysis has been used in many applications, especially medical imaging, but rarely in traditional remote sensing. In part this is because the memory requirements are substantial when handling large areas, but with modern computing and storage this is no longer a significant impediment. Our reason for using voxels to model scenes from LIDAR data is that there are several advantages over standard triangle-based models, including better handling of overlapping surfaces and complex shapes. We show how incorporating system position information from early in the LIDAR point cloud generation process allows radiometrically-correct transmission and other novel voxel properties to be recovered. This voxelization technique is validated on simulated data using the Digital Imaging and Remote Sensing Image Generation (DIRSIG) software, a first-principles based ray-tracer developed at the Rochester Institute of Technology. Voxel-based modeling of LIDAR can be useful on its own, but we believe its primary advantage is when applied to problems where simpler surface-based 3D models conflict with the requirement of realistic geometry. To

  3. Uncertainty Analysis of Instrument Calibration and Application

    NASA Technical Reports Server (NTRS)

    Tripp, John S.; Tcheng, Ping

    1999-01-01

    Experimental aerodynamic researchers require estimated precision and bias uncertainties of measured physical quantities, typically at 95 percent confidence levels. Uncertainties of final computed aerodynamic parameters are obtained by propagation of individual measurement uncertainties through the defining functional expressions. In this paper, rigorous mathematical techniques are extended to determine precision and bias uncertainties of any instrument-sensor system. Through this analysis, instrument uncertainties determined through calibration are now expressed as functions of the corresponding measurement for linear and nonlinear univariate and multivariate processes. Treatment of correlated measurement precision error is developed. During laboratory calibration, calibration standard uncertainties are assumed to be an order of magnitude less than those of the instrument being calibrated. Often calibration standards do not satisfy this assumption. This paper applies rigorous statistical methods for inclusion of calibration standard uncertainty and covariance due to the order of their application. The effects of mathematical modeling error on calibration bias uncertainty are quantified. The effects of experimental design on uncertainty are analyzed. The importance of replication is emphasized, techniques for estimation of both bias and precision uncertainties using replication are developed. Statistical tests for stationarity of calibration parameters over time are obtained.

  4. Decision analysis applications and the CERCLA process

    SciTech Connect

    Purucker, S.T.; Lyon, B.F. |

    1994-06-01

    Quantitative decision methods can be developed during environmental restoration projects that incorporate stakeholder input and can complement current efforts that are undertaken for data collection and alternatives evaluation during the CERCLA process. These decision-making tools can supplement current EPA guidance as well as focus on problems that arise as attempts are made to make informed decisions regarding remedial alternative selection. In examining the use of such applications, the authors discuss the use of decision analysis tools and their impact on collecting data and making environmental decisions from a risk-based perspective. They will look at the construction of objective functions for quantifying different risk-based perspective. They will look at the construction of objective functions for quantifying different risk-based decision rules that incorporate stakeholder concerns. This represents a quantitative method for implementing the Data Quality Objective (DQO) process. These objective functions can be expressed using a variety of indices to analyze problems that currently arise in the environmental field. Examples include cost, magnitude of risk, efficiency, and probability of success or failure. Based on such defined objective functions, a project can evaluate the impact of different risk and decision selection strategies on data worth and alternative selection.

  5. Digraph matrix analysis applications to systems interactions

    SciTech Connect

    Alesso, H.P.; Altenbach, T.; Lappa, D.; Kimura, C.; Sacks, I.J.; Ashmore, B.C.; Fromme, D.; Smith, C.F.; Williams, W.

    1984-01-01

    Complex events such as Three Mile Island-2, Brown's Ferry-3 and Crystal River-3 have demonstrated that previously unidentified system interdependencies can be important to safety. A major aspect of these events was dependent faults (common cause/mode failures). The term systems interactions has been introduced by the Nuclear Regulatory Commission (NRC) to identify the concepts of spatial and functional coupling of systems which can lead to system interdependencies. Spatial coupling refers to dependencies resulting from a shared environmental condition; functional coupling refers to both dependencies resulting from components shared between safety and/or support systems, and to dependencies involving human actions. The NRC is currently developing guidelines to search for and evaluate adverse systems interactions at light water reactors. One approach utilizes graph theoretical methods and is called digraph matrix analysis (DMA). This methodology has been specifically tuned to the systems interaction problem. The objective of this paper is to present results from two DMA applications and to contrast them with the results from more traditional fault tree approaches.

  6. Neutron Activation Analysis: Techniques and Applications

    SciTech Connect

    MacLellan, Ryan

    2011-04-27

    The role of neutron activation analysis in low-energy low-background experimentsis discussed in terms of comparible methods. Radiochemical neutron activation analysis is introduce. The procedure of instrumental neutron activation analysis is detailed especially with respect to the measurement of trace amounts of natural radioactivity. The determination of reactor neutron spectrum parameters required for neutron activation analysis is also presented.

  7. Fabrication of highly transparent diamond-like carbon anti-reflecting coating for Si solar cell application

    SciTech Connect

    Banerjee, Amit Das, Debajyoti

    2014-04-24

    ARC grade highly transparent unhydrogenated diamond-like carbon (DLC) films were produced, directly from a-C target, using RF magnetron sputtering deposition technique, for optoelectronic applications. Optical band gap, transmittance, reflectance, sp{sup 3} fraction, I{sub D}/I{sub G}, density, and refractive index of the films have been estimated with the help of optical tools like Uv-vis spectrophotometer, ellipsometer and micro-Raman. Optimum ARC-qualities have been identified in low-temperature grown DLC films at an Ar pressure of 4 mTorr in the reactor, accomplishing its key requirements for use in silicon solar cells.

  8. Analysis of small commercial photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Herz, J.; Allred, R.; McCarthy, R.

    1982-07-01

    The objective was to determine promising small commercial (to 500 kW) grid connected photovoltaic applications. Twelve applications were evaluated, including detailed performance and economic analyses covering different collector types, utility rate structures and geographic locations. The attractiveness of battery storage was also examined.

  9. FT-IR, Micro-Raman and UV-vis spectroscopic and quantum chemical investigations of free 2,2'-dithiodipyridine and its metal (Co, Cu and Zn) halide complexes

    NASA Astrophysics Data System (ADS)

    Gökce, Halil; Bahçeli, Semiha

    2013-10-01

    In this study the elemental analysis results, molecular geometries, vibrational and electronic absorption spectra of free 2,2'-dithiodipyridine(C10H8N2S2), (or DTDP) (with synonym, 2,2'-dipyridyl disulfide) and M(C10H8N2S2)Cl2 (M = Co, Cu and Zn) complexes have been reported. Vibrational wavenumbers of free DTDP and its metal halide complexes have been calculated by using DFT/B3LYP calculation method with 6-31++G(d,p) and Lanl2DZ basis sets, respectively, in the ground state, for the first time. The calculated fundamental vibrational frequencies are in a good agreement with experimental data. The HOMO, LUMO and MEP analyses of all compounds are performed by DFT method.

  10. Image analysis applications for grain science

    NASA Astrophysics Data System (ADS)

    Zayas, Inna Y.; Steele, James L.

    1991-02-01

    Morphometrical features of single grain kernels or particles were used to discriminate two visibly similar wheat varieties foreign material in wheat hardsoft and spring-winter wheat classes and whole from broken corn kernels. Milled fractions of hard and soft wheat were evaluated using textural image analysis. Color image analysis of sound and mold damaged corn kernels yielded high recognition rates. The studies collectively demonstrate the potential for automated classification and assessment of grain quality using image analysis.

  11. PREFACE: Dielectrics 2009: Measurement Analysis and Applications

    NASA Astrophysics Data System (ADS)

    Vaughan, Alun; Williams, Graham

    2009-07-01

    The conference Dielectrics 2009: Measurements, Analysis and Applications represents a significant milestone in the evolution of dielectrics research in the UK. It is reasonable to state that the academic study of dielectrics has led to many fundamental advances and that dielectric materials underpin the modern world in devices ranging from field effect transistors, which operate at extremely high fields, albeit low voltages, to the high voltage plants that provide the energy that powers our economy. The origins of the Dielectrics Group of the Institute of Physics (IOP), which organized this conference, can be traced directly back to the early 1960s, when Professor Mansel Davies was conducting research into the dielectric relaxation behaviour of polar liquids and solids at The Edward Davies Chemical Laboratories of the University College of Wales, Aberystwyth. He was already well-known internationally for his studies of molecular structure and bonding of small molecules, using infra-red-spectroscopy, and of the physical properties of hydrogen-bonded liquids and solids, using thermodynamic methods. Dielectric spectroscopy was a fairly new area for him and he realized that opportunities for scientists in the UK to gather together and discuss their research in this developing area of physical chemistry/chemical physics were very limited. He conceived the idea of forming a Dielectrics Discussion Group (DDG), which would act as a meeting point and provide a platform for dielectrics research in the UK and beyond and, as a result, a two-day Meeting was convened in the spring of 1968 at Gregynog Hall of the University of Wales, near Newtown, Montgomeryshire. It was organized by Mansel Davies, Alun Price and Graham Williams, all physical chemists from the UCW, Aberystwyth. Fifty scientists attended, being a mix of physical chemists, theoretical chemists, physicists, electrical engineers, polymer and materials scientists, all from the UK, except Dr Brendan Scaife of Trinity

  12. Regression Analysis: Legal Applications in Institutional Research

    ERIC Educational Resources Information Center

    Frizell, Julie A.; Shippen, Benjamin S., Jr.; Luna, Andrew L.

    2008-01-01

    This article reviews multiple regression analysis, describes how its results should be interpreted, and instructs institutional researchers on how to conduct such analyses using an example focused on faculty pay equity between men and women. The use of multiple regression analysis will be presented as a method with which to compare salaries of…

  13. Miscue Analysis: Applications to Reading Instruction.

    ERIC Educational Resources Information Center

    Goodman, Kenneth S., Ed.

    This book is a series of essays on the subject of miscue analysis, a diagnostic procedure rooted in the psycholinguistic view of reading. The focus of miscue analysis is on the broad field of reading comprehension rather than the isolated decoding of individual words and letters. The contents of this book include: "Introduction" by Sister Rosemary…

  14. Computer applications for engineering/structural analysis

    SciTech Connect

    Zaslawsky, M.; Samaddar, S.K.

    1991-01-01

    Analysts and organizations have a tendency to lock themselves into specific codes with the obvious consequences of not addressing the real problem and thus reaching the wrong conclusion. This paper discusses the role of the analyst in selecting computer codes. The participation and support of a computation division in modifying the source program, configuration management, and pre- and post-processing of codes are among the subjects discussed. Specific examples illustrating the computer code selection process are described in the following problem areas: soil structure interaction, structural analysis of nuclear reactors, analysis of waste tanks where fluid structure interaction is important, analysis of equipment, structure-structure interaction, analysis of the operation of the superconductor supercollider which includes friction and transient temperature, and 3D analysis of the 10-meter telescope being built in Hawaii. Validation and verification of computer codes and their impact on the selection process are also discussed.

  15. Computer applications for engineering/structural analysis

    NASA Astrophysics Data System (ADS)

    Zaslawsky, M.; Samaddar, S. K.

    1991-10-01

    Analysts and organizations have a tendency to lock themselves into specific codes with the obvious consequence of not addressing the real problem and thus reaching the wrong conclusion. This paper discusses the role of the analyst in selecting computer codes. The participation and support of a computation division in modifying the source program, configuration management, and pre- and post-processing of codes are among the subjects discussed. Specific examples illustrating the computer code selection process are described in the following problem areas: soil structure interaction, structural analysis of nuclear reactors, analysis of waste tanks where fluid structure interaction is important, analysis of equipment, structure-structure interaction, analysis of the operation of the superconductor supercollider which includes friction and transient temperature, and 3D analysis of the 10-meter telescope being built in Hawaii. Validation and verification of computer codes and their impact on the selection process are also discussed.

  16. Cross-impacts analysis development and energy policy analysis applications

    SciTech Connect

    Roop, J.M.; Scheer, R.M.; Stacey, G.S.

    1986-12-01

    Purpose of this report is to describe the cross-impact analysis process and microcomputer software developed for the Office of Policy, Planning, and Analysis (PPA) of DOE. First introduced in 1968, cross-impact analysis is a technique that produces scenarios of future conditions and possibilities. Cross-impact analysis has several unique attributes that make it a tool worth examining, especially in the current climate when the outlook for the economy and several of the key energy markets is uncertain. Cross-impact analysis complements the econometric, engineering, systems dynamics, or trend approaches already in use at DOE. Cross-impact analysis produces self-consistent scenarios in the broadest sense and can include interaction between the economy, technology, society and the environment. Energy policy analyses that couple broad scenarios of the future with detailed forecasting can produce more powerful results than scenario analysis or forecasts can produce alone.

  17. Space Telecommunications Radio System (STRS) Application Repository Design and Analysis

    NASA Technical Reports Server (NTRS)

    Handler, Louis M.

    2013-01-01

    The Space Telecommunications Radio System (STRS) Application Repository Design and Analysis document describes the STRS application repository for software-defined radio (SDR) applications intended to be compliant to the STRS Architecture Standard. The document provides information about the submission of artifacts to the STRS application repository, to provide information to the potential users of that information, and for the systems engineer to understand the requirements, concepts, and approach to the STRS application repository. The STRS application repository is intended to capture knowledge, documents, and other artifacts for each waveform application or other application outside of its project so that when the project ends, the knowledge is retained. The document describes the transmission of technology from mission to mission capturing lessons learned that are used for continuous improvement across projects and supporting NASA Procedural Requirements (NPRs) for performing software engineering projects and NASAs release process.

  18. BOREHOLE FLOWMETERS: FIELD APPLICATION AND DATA ANALYSIS

    EPA Science Inventory

    This paper reviews application of borehole flowmeters in granular and fractured rocks. Basic data obtained in the field are the ambient flow log and the pumping-induced flow log. These basic logs may then be used to calculate other quantities of interest. The paper describes the ...

  19. APPLICATION ANALYSIS REPORT: RETECH PLASMA CENTRIFUGAL FURNACE

    EPA Science Inventory

    This document is an evaluation of the performance of the Retech, Inc. Plasma Centrifugal Furnace (PCF) and its applicability as a treatment for soils contaminated with organic and/or inorganic compounds. Both the technical and economic aspectsof the technology were examined. A...

  20. BOREHOLE FLOWMETERS: FIELD APPLICATION AND DATA ANALYSIS

    EPA Science Inventory

    This paper reviews application of borehole flowmeters in granular and fractured rocks. asic data obtained in the field are the ambient flow log and the pumping-induced flow log. hese basic logs may then be used to calculate other quantities of interest. he paper describes the app...

  1. Some archaeologic applications of accelerator radiocarbon analysis

    NASA Astrophysics Data System (ADS)

    Donahue, D. J.; Jull, A. J. T.; Linick, T. W.

    1990-01-01

    The method of preparation of archaeologic samples for AMS radiocarbon dating, the precision of such measurements and the conversion of radiocarbon results to calendar ages are presented. The application of the technique to measurements of the ages of bones, textiles (including the Shroud of Turin), cultigens and other achaeologic artifacts is described.

  2. SHIRCO INFRARED INCINERATION SYSTEM: APPLICATIONS ANALYSIS REPORT

    EPA Science Inventory

    This document is an evaluation of the Shirco infrared Thermal Destruction Technology and its applicability as an on-site treatment method for waste site clean-ups. A Superfund Innovative Technical Evaluation (SITE) was conducted on a lOO-ton day unit during a removal action at Br...

  3. Guidebook for analysis of tether applications

    NASA Technical Reports Server (NTRS)

    Carroll, J. A.

    1985-01-01

    This guidebook is intended as a tool to facilitate initial analyses of proposed tether applications in space. Topics disscussed include: orbit and orbit transfer equations; orbital perturbations; aerodynamic drag; thermal balance; micrometeoroids; gravity gradient effects; tether control strategies; momentum transfer; orbit transfer by tethered release/rendezvous; impact hazards for tethers; electrodynamic tether principles; and electrodynamic libration control issues.

  4. Cost analysis of energy storage systems for electric utility applications

    SciTech Connect

    Akhil, A.; Swaminathan, S.; Sen, R.K.

    1997-02-01

    Under the sponsorship of the Department of Energy, Office of Utility Technologies, the Energy Storage System Analysis and Development Department at Sandia National Laboratories (SNL) conducted a cost analysis of energy storage systems for electric utility applications. The scope of the study included the analysis of costs for existing and planned battery, SMES, and flywheel energy storage systems. The analysis also identified the potential for cost reduction of key components.

  5. [Advances in independent component analysis and its application].

    PubMed

    Chen, Huafu; Yao, Dezhong

    2003-06-01

    The independent component analysis (ICA) is a new technique in statistical signal processing, which decomposes mixed signals into statistical independent components. The reported applications in biomedical and radar signal have demonstrated its good prospect in various blind signal separation. In this paper, the progress of ICA in such as its principle, algorithm and application and advance direction of ICA in future is reviewed. The aim is to promote the research in theory and application in the future. PMID:12856621

  6. Potential applications of computational fluid dynamics to biofluid analysis

    NASA Technical Reports Server (NTRS)

    Kwak, D.; Chang, J. L. C.; Rogers, S. E.; Rosenfeld, M.; Kwak, D.

    1988-01-01

    Computational fluid dynamics was developed to the stage where it has become an indispensable part of aerospace research and design. In view of advances made in aerospace applications, the computational approach can be used for biofluid mechanics research. Several flow simulation methods developed for aerospace problems are briefly discussed for potential applications to biofluids, especially to blood flow analysis.

  7. An Automated Inadvertent Intruder Analysis Application

    SciTech Connect

    KOFFMAN, LARRYD.

    2004-07-17

    Savannah River National Laboratory is responsible for the radiological performance assessment analysis for Savannah River Site waste disposal facilities (McDowell-Boyer2000), which results in limits on the amounts of radiological substances that can be placed in the waste disposal facilities. To arrive at these limits, the performance assessment considers numerous potential exposure pathways that could occur in the future. One set of exposure scenarios, known as inadvertent intruder analysis, considers the impact on hypothetical individuals who are assumed to inadvertently intrude onto the waste disposal site. Inadvertent intruder analysis considers three distinct scenarios for exposure referred to as the agriculture scenario, the resident scenario, and the post-drilling scenario. Each of these scenarios has specific exposure pathways that contribute to the overall dose for the scenario.

  8. Applications of breath gas analysis in medicine

    NASA Astrophysics Data System (ADS)

    Amann, Anton; Poupart, Guy; Telser, Stefan; Ledochowski, Maximilian; Schmid, Alex; Mechtcheriakov, Sergei

    2004-12-01

    Volatile organic compounds (VOCs) in exhaled breath gas provide valuable information about the subjects' physiological and pathophysiological condition. Proton-transfer-reaction mass spectrometry (PTR-MS) allows rapid and online measurements of these substances. We present results of three studies illustrating the potential of breath gas analysis by PTR-MS in various contexts: long-time online monitoring of VOCs in sleeping subjects suggests that VOC profiles are related to sleep stages. Analysis of VOC concentrations in the breath of carbohydrate malabsorbers emphasizes the role played by bacteria in the gut. Finally, we demonstrate the large intra- and intersubject concentration variability of VOCs by considering one particular mass.

  9. PREFACE: Dielectrics 2009: Measurement Analysis and Applications

    NASA Astrophysics Data System (ADS)

    Vaughan, Alun; Williams, Graham

    2009-07-01

    The conference Dielectrics 2009: Measurements, Analysis and Applications represents a significant milestone in the evolution of dielectrics research in the UK. It is reasonable to state that the academic study of dielectrics has led to many fundamental advances and that dielectric materials underpin the modern world in devices ranging from field effect transistors, which operate at extremely high fields, albeit low voltages, to the high voltage plants that provide the energy that powers our economy. The origins of the Dielectrics Group of the Institute of Physics (IOP), which organized this conference, can be traced directly back to the early 1960s, when Professor Mansel Davies was conducting research into the dielectric relaxation behaviour of polar liquids and solids at The Edward Davies Chemical Laboratories of the University College of Wales, Aberystwyth. He was already well-known internationally for his studies of molecular structure and bonding of small molecules, using infra-red-spectroscopy, and of the physical properties of hydrogen-bonded liquids and solids, using thermodynamic methods. Dielectric spectroscopy was a fairly new area for him and he realized that opportunities for scientists in the UK to gather together and discuss their research in this developing area of physical chemistry/chemical physics were very limited. He conceived the idea of forming a Dielectrics Discussion Group (DDG), which would act as a meeting point and provide a platform for dielectrics research in the UK and beyond and, as a result, a two-day Meeting was convened in the spring of 1968 at Gregynog Hall of the University of Wales, near Newtown, Montgomeryshire. It was organized by Mansel Davies, Alun Price and Graham Williams, all physical chemists from the UCW, Aberystwyth. Fifty scientists attended, being a mix of physical chemists, theoretical chemists, physicists, electrical engineers, polymer and materials scientists, all from the UK, except Dr Brendan Scaife of Trinity

  10. Nonlinear Principal Components Analysis: Introduction and Application

    ERIC Educational Resources Information Center

    Linting, Marielle; Meulman, Jacqueline J.; Groenen, Patrick J. F.; van der Koojj, Anita J.

    2007-01-01

    The authors provide a didactic treatment of nonlinear (categorical) principal components analysis (PCA). This method is the nonlinear equivalent of standard PCA and reduces the observed variables to a number of uncorrelated principal components. The most important advantages of nonlinear over linear PCA are that it incorporates nominal and ordinal…

  11. Theory and Application of DNA Histogram Analysis.

    ERIC Educational Resources Information Center

    Bagwell, Charles Bruce

    The underlying principles and assumptions associated with DNA histograms are discussed along with the characteristics of fluorescent probes. Information theory was described and used to calculate the information content of a DNA histogram. Two major types of DNA histogram analyses are proposed: parametric and nonparametric analysis. Three levels…

  12. Electron Spectroscopy: Applications for Chemical Analysis

    ERIC Educational Resources Information Center

    Heercules, David M.

    2004-01-01

    The development of XPS as an effective method for surface analysis during the period 1964-1977 is presented. The study shows that unlike other surface methods, XPS data can be obtained for both conductors and insulators and a variety of samples can be handled effectively, which is one of the major reasons for the popularity of the technique.

  13. Principles of Discourse Analysis: Explanation and Applications.

    ERIC Educational Resources Information Center

    Marzano, Robert J.

    Discourse analysis attempts to identify and describe the semantic relationships among units of thought larger than a word (predications). Two basic types of these relationships exist between predications, conceptual and nonconceptual. A conceptual relationship exists between two predications when they share a concept or when a concept in one…

  14. Micro-Raman imaging spectroscopy of suspended graphene

    NASA Astrophysics Data System (ADS)

    Simpson, J. R.; Hight Walker, A. R.

    2009-03-01

    The recent observationootnotetextK. I. Bolotin et al., Solid State Commun. 146, 351 (2008). of ultrahigh mobility, >200,000,s-1, in suspended and annealed graphene underscores the importance of environmental effects on graphene electronic properties. We compare the Raman spectra of graphene and chemically modified graphite oxide both in contact with and suspended above substrate surfaces. Graphene samples were prepared using micromechanical cleavage and chemically modifiedootnotetextJ. T. Robinson et al., Nano Lett. 8, 3441 (2008). graphite flakes on silicon substrates with a thin, 300,nm, silicon oxide coating. Reactive ion etching patterns the substrates with circular holes, approximately 3-7,m in diameter, etched through the oxide layer. We present spatially-resolved Raman spectra obtained in a scanning, confocal microscope configuration using 632.8,m and 514.5,m laser excitation.

  15. Uncooled LWIR imaging: applications and market analysis

    NASA Astrophysics Data System (ADS)

    Takasawa, Satomi

    2015-05-01

    The evolution of infrared (IR) imaging sensor technology for defense market has played an important role in developing commercial market, as dual use of the technology has expanded. In particular, technologies of both reduction in pixel pitch and vacuum package have drastically evolved in the area of uncooled Long-Wave IR (LWIR; 8-14 μm wavelength region) imaging sensor, increasing opportunity to create new applications. From the macroscopic point of view, the uncooled LWIR imaging market is divided into two areas. One is a high-end market where uncooled LWIR imaging sensor with sensitivity as close to that of cooled one as possible is required, while the other is a low-end market which is promoted by miniaturization and reduction in price. Especially, in the latter case, approaches towards consumer market have recently appeared, such as applications of uncooled LWIR imaging sensors to night visions for automobiles and smart phones. The appearance of such a kind of commodity surely changes existing business models. Further technological innovation is necessary for creating consumer market, and there will be a room for other companies treating components and materials such as lens materials and getter materials and so on to enter into the consumer market.

  16. Ordinal symbolic analysis and its application to biomedical recordings

    PubMed Central

    Amigó, José M.; Keller, Karsten; Unakafova, Valentina A.

    2015-01-01

    Ordinal symbolic analysis opens an interesting and powerful perspective on time-series analysis. Here, we review this relatively new approach and highlight its relation to symbolic dynamics and representations. Our exposition reaches from the general ideas up to recent developments, with special emphasis on its applications to biomedical recordings. The latter will be illustrated with epilepsy data. PMID:25548264

  17. Applications of cluster analysis to satellite soundings

    NASA Technical Reports Server (NTRS)

    Munteanu, M. J.; Jakubowicz, O.; Kalnay, E.; Piraino, P.

    1984-01-01

    The advantages of the use of cluster analysis in the improvement of satellite temperature retrievals were evaluated since the use of natural clusters, which are associated with atmospheric temperature soundings characteristic of different types of air masses, has the potential for improving stratified regression schemes in comparison with currently used methods which stratify soundings based on latitude, season, and land/ocean. The method of discriminatory analysis was used. The correct cluster of temperature profiles from satellite measurements was located in 85% of the cases. Considerable improvement was observed at all mandatory levels using regression retrievals derived in the clusters of temperature (weighted and nonweighted) in comparison with the control experiment and with the regression retrievals derived in the clusters of brightness temperatures of 3 MSU and 5 IR channels.

  18. Integrated fire analysis: Application to offshore cases

    SciTech Connect

    Saubestre, V.; Khalfi, J.P.; Paygnard, J.C.

    1995-12-31

    Evaluating thermal loads from different fire scenarios and then response of the structure to these loads covers several fields. It is also difficult and time consuming to implement. Interfaces are necessary between the heat calculation, transient propagation and structural analysis software packages. Nevertheless, it is necessary to design structures to accommodate heat loads in order to meet safety requirements or functional specification. Elf, along with several operators and organizations, have sponsored a research project on this topic. The project, managed by SINTEF NBL (Norwegian Fire Research Laboratory), has delivered an integrated fire analysis software package which can be used to address design-to-fire-related issues in various contexts. The core modules of the integrated package are robust, well validated analysis tools. This paper describes some benefits (technical or cost related) of using an integrated approach to assess the response of a structure to thermal loads. Three examples are described: consequence of an accidental scenario on the living quarters in an offshore complex, necessity for the reinforcement of a flareboom following a change in process, evaluation of the amount of insulation needed for a topside process primary structure. The paper focuses on the importance for the operator to have a practical tool which can lead to substantial cost saving while reducing the uncertainty linked to safety issues.

  19. Towards sentiment analysis application in housing projects

    NASA Astrophysics Data System (ADS)

    Mahadzir, Nurul Husna; Omar, Mohd Faizal; Nawi, Mohd Nasrun Mohd

    2016-08-01

    In becoming a develop nation by 2020, Malaysia Government realized the need in providing affordable house to the public. Since Second Malaysia Plan, government has implemented various affordable housing projects and it continues until recent Malaysia Plan. To measure the effectiveness of the initiatives taken, public opinion is necessary. A social media platform has been seen as the most effective mechanism to get information on people's thought and feeling towards certain issues. One of the best ways to extract emotions and thoughts from what people post in social media is through Sentiment Analysis (SA). There are three different levels of analysis: document level, sentence level and feature level. Most of previous research focused on the classification of sentiment at document or sentence level. Unfortunately, both document and sentence level does not discover what exactly people like or not. While the analysis based on feature, there exist accuracy problem when classifying the sentiment scores. This paper will propose a new framework that focuses on sentiment classification scores at feature level to overcome the uncertainty and accuracy issues on the result.

  20. Fatty acid oxidation: systems analysis and applications.

    PubMed

    Cintolesi, Angela; Rodríguez-Moyá, María; Gonzalez, Ramon

    2013-01-01

    Fatty acids (FAs) are essential components of cellular structure and energy-generating routes in living organisms. They exist in a variety of chemical configurations and functionalities and are catabolized by different oxidative routes, according to their structure. α- and ω-Oxidation are minor routes that occur only in eukaryotes, while β-oxidation is the major degradation route in eukaroytes and prokaryotes. These pathways have been characterized and engineered from different perspectives for industrial and biomedical applications. The severity of FA oxidation disorders in humans initially guided the study of FA metabolism at a molecular-level. On the other hand, recent advances in metabolic engineering and systems biology have powered the study of FA biosynthetic and catabolic routes in microorganisms at a systems-level. Several studies have proposed these pathways as platforms for the production of fuels and chemicals from biorenewable sources. The lower complexity of microbial systems has allowed a more comprehensive study of FA metabolism and has opened opportunities for a wider range of applications. Still, there is a need for techniques that facilitate the translation of high-throughput data from microorganisms to more complex eukaryotic systems in order to aid the development of diagnostic and treatment strategies for FA oxidation disorders. In addition, further systems biology analyses on human systems could also provide valuable insights on oxidation disorders. This article presents a comparison of the three main FA oxidative routes, systems biology analyses that have been used to study FA metabolism, and engineering efforts performed on microbial systems. PMID:23661533

  1. Applications of activation analysis to geochemical, meteoritic and lunar studies.

    NASA Technical Reports Server (NTRS)

    Showalter, D. L.; Schmitt, R. A.

    1972-01-01

    The application of activation analysis techniques to the analysis of cosmological materials, i.e., terrestrial, tektitic, meteoritic, and lunar matter, is reviewed. Elemental determinations can be made by instrumental fast-neutron and thermal-neutron activation analysis, photonuclear and charged-particle activation analysis, and by radiochemical neutron activation analysis. Partition-coefficient methods, autoradiography studies, gamma-gamma coincidence counting, and age determination by neutron activation are discussed. Attention is given to K-Ar and I-Xe dating of meteorites.

  2. Application of multidisciplinary analysis to gene expression.

    SciTech Connect

    Wang, Xuefel; Kang, Huining; Fields, Chris; Cowie, Jim R.; Davidson, George S.; Haaland, David Michael; Sibirtsev, Valeriy; Mosquera-Caro, Monica P.; Xu, Yuexian; Martin, Shawn Bryan; Helman, Paul; Andries, Erik; Ar, Kerem; Potter, Jeffrey; Willman, Cheryl L.; Murphy, Maurice H.

    2004-01-01

    Molecular analysis of cancer, at the genomic level, could lead to individualized patient diagnostics and treatments. The developments to follow will signal a significant paradigm shift in the clinical management of human cancer. Despite our initial hopes, however, it seems that simple analysis of microarray data cannot elucidate clinically significant gene functions and mechanisms. Extracting biological information from microarray data requires a complicated path involving multidisciplinary teams of biomedical researchers, computer scientists, mathematicians, statisticians, and computational linguists. The integration of the diverse outputs of each team is the limiting factor in the progress to discover candidate genes and pathways associated with the molecular biology of cancer. Specifically, one must deal with sets of significant genes identified by each method and extract whatever useful information may be found by comparing these different gene lists. Here we present our experience with such comparisons, and share methods developed in the analysis of an infant leukemia cohort studied on Affymetrix HG-U95A arrays. In particular, spatial gene clustering, hyper-dimensional projections, and computational linguistics were used to compare different gene lists. In spatial gene clustering, different gene lists are grouped together and visualized on a three-dimensional expression map, where genes with similar expressions are co-located. In another approach, projections from gene expression space onto a sphere clarify how groups of genes can jointly have more predictive power than groups of individually selected genes. Finally, online literature is automatically rearranged to present information about genes common to multiple groups, or to contrast the differences between the lists. The combination of these methods has improved our understanding of infant leukemia. While the complicated reality of the biology dashed our initial, optimistic hopes for simple answers from

  3. Hand geometry field application data analysis

    SciTech Connect

    Ruehle, M.; Ahrens, J.

    1997-03-01

    Over the last fifteen years, Sandia National Laboratories Security Systems and Technology Center, Department 5800, has been involved in several laboratory tests of various biometric identification devices. These laboratory tests were conducted to verify the manufacturer`s performance claims, to determine strengths and weaknesses of particular devices, and to evaluate which devices meet the US Department of Energy`s unique needs for high-security devices. However, during a recent field installation of one of these devices, significantly different performance was observed than had been predicted by these laboratory tests. This report documents the data analysis performed in the search for an explanation of these differences.

  4. Analysis of wavelet technology for NASA applications

    NASA Technical Reports Server (NTRS)

    Wells, R. O., Jr.

    1994-01-01

    The purpose of this grant was to introduce a broad group of NASA researchers and administrators to wavelet technology and to determine its future role in research and development at NASA JSC. The activities of several briefings held between NASA JSC scientists and Rice University researchers are discussed. An attached paper, 'Recent Advances in Wavelet Technology', summarizes some aspects of these briefings. Two proposals submitted to NASA reflect the primary areas of common interest. They are image analysis and numerical solutions of partial differential equations arising in computational fluid dynamics and structural mechanics.

  5. Application of TIMS data in stratigraphic analysis

    NASA Technical Reports Server (NTRS)

    Lang, H. R.

    1986-01-01

    An in-progress study demonstrates the utility of Thermal Infrared Multispectral Scanner (TIMS) data for unraveling the stratigraphic sequence of a western interior, North American foreland basin. The TIMS data can be used to determine the stratigraphic distribution of minerals that are diagnostic of specific depositional distribution. The thematic mapper (TM) and TIMS data were acquired in the Wind River/Bighorn area of central Wyoming in November 1982, and July 1983, respectively. Combined image processing, photogeologic, and spectral analysis methods were used to: map strata; construct stratigraphic columns; correlate data; and identify mineralogical facies.

  6. Applications of immobilized biocatalysts in chemical analysis

    SciTech Connect

    Bowers, L.D.

    1986-04-01

    In 1974, Weetall published a report in Analytical Chemistry documenting the increasing interest in a relatively new concept in catalysis involving enzymes physically or covalently bound to a solid support. Very few reports of a new immobilization chemistry can stir enthusiasm, and the descriptions of new analysis systems have become less and less frequent. With these advances in mind, it seems appropriate to evaluate the use of immobilized enzymes as routine laboratory tools, a prediction made in 1976 (2), and the reasons for the success or failure of the technique. 20 references, 5 figures, 2 tables.

  7. Applications of Ergodic Theory to Coverage Analysis

    NASA Technical Reports Server (NTRS)

    Lo, Martin W.

    2003-01-01

    The study of differential equations, or dynamical systems in general, has two fundamentally different approaches. We are most familiar with the construction of solutions to differential equations. Another approach is to study the statistical behavior of the solutions. Ergodic Theory is one of the most developed methods to study the statistical behavior of the solutions of differential equations. In the theory of satellite orbits, the statistical behavior of the orbits is used to produce 'Coverage Analysis' or how often a spacecraft is in view of a site on the ground. In this paper, we consider the use of Ergodic Theory for Coverage Analysis. This allows us to greatly simplify the computation of quantities such as the total time for which a ground station can see a satellite without ever integrating the trajectory, see Lo 1,2. More over, for any quantity which is an integrable function of the ground track, its average may be computed similarly without the integration of the trajectory. For example, the data rate for a simple telecom system is a function of the distance between the satellite and the ground station. We show that such a function may be averaged using the Ergodic Theorem.

  8. Silicon Substrate Strained and Structured via Cavitation Effect for Photovoltaic and Biomedical Application.

    PubMed

    Savkina, Rada K; Gudymenko, Aleksandr I; Kladko, Vasyl P; Korchovyi, Andrii A; Nikolenko, Andrii S; Smirnov, Aleksey B; Stara, Tatyana R; Strelchuk, Viktor V

    2016-12-01

    A hybrid structure, which integrates the nanostructured silicon with a bio-active silicate, is fabricated using the method of MHz sonication in the cryogenic environment. Optical, atomic force, and scanning electron microscopy techniques as well as energy dispersive X-ray spectroscopy were used for the investigation of the morphology and chemical compound of the structured surface. Micro-Raman as well as X-ray diffraction, ellipsometry, and photovoltage spectroscopy was used for the obtained structures characterization. Ellipsometer measurements demonstrated the formation of the layer with the thicknesses ~700 nm and optical parameters closed to SiO2 compound with an additional top layer of the thicknesses ~15 nm and the refractive index ~1. Micro-Raman investigation detects an appearance of Ca-O local vibrational mode, and the stretching vibration of SiO4 chains characterized the wollastonite form of CaSiO3. A significant rise in the value and an expansion of the spectral range of the surface photovoltage for silicon structured via the megasonic processing was found. The concept of biocompatible photovoltaic cell on the base of Si\\CaSiO3 structure for the application in bioelectronics was proposed. PMID:27067731

  9. Silicon Substrate Strained and Structured via Cavitation Effect for Photovoltaic and Biomedical Application

    NASA Astrophysics Data System (ADS)

    Savkina, Rada K.; Gudymenko, Aleksandr I.; Kladko, Vasyl P.; Korchovyi, Andrii A.; Nikolenko, Andrii S.; Smirnov, Aleksey B.; Stara, Tatyana R.; Strelchuk, Viktor V.

    2016-04-01

    A hybrid structure, which integrates the nanostructured silicon with a bio-active silicate, is fabricated using the method of MHz sonication in the cryogenic environment. Optical, atomic force, and scanning electron microscopy techniques as well as energy dispersive X-ray spectroscopy were used for the investigation of the morphology and chemical compound of the structured surface. Micro-Raman as well as X-ray diffraction, ellipsometry, and photovoltage spectroscopy was used for the obtained structures characterization. Ellipsometer measurements demonstrated the formation of the layer with the thicknesses ~700 nm and optical parameters closed to SiO2 compound with an additional top layer of the thicknesses ~15 nm and the refractive index ~1. Micro-Raman investigation detects an appearance of Ca-O local vibrational mode, and the stretching vibration of SiO4 chains characterized the wollastonite form of CaSiO3. A significant rise in the value and an expansion of the spectral range of the surface photovoltage for silicon structured via the megasonic processing was found. The concept of biocompatible photovoltaic cell on the base of Si/CaSiO3 structure for the application in bioelectronics was proposed.

  10. Malpractice claims analysis yields widely applicable principles.

    PubMed

    Waldman, J D; Spector, R A

    2003-01-01

    We received 50 claims of medical negligence in pediatric cardiology. From the analysis, patterns were identified and recommendations for improvement were found that apply generally to healthcare. Less than half (38%) of the claims were found to be medically meritorious. The impression of substandard care was often (7/50) created by an erroneous attribution of cause of death at autopsy. Both structured learning for caregivers and education of the public will reduce the frequency of malpractice forms-both valid and frivolous. Caregivers should document more effectively. The current tort system neither deters nor compensates as it was intended. The assignment of blame to a single individual is usually not in concert with the reality of modern medicine. Good health care is not a passive behavior; active participation by the public is required. PMID:12360392