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Sample records for 350-2500 nm spectra

  1. Reflectance spectroscopy (350-2500 nm) of solid-state polycyclic aromatic hydrocarbons (PAHs)

    NASA Astrophysics Data System (ADS)

    Izawa, M. R. M.; Applin, D. M.; Norman, L.; Cloutis, E. A.

    2014-07-01

    Polycyclic aromatic hydrocarbons (PAHs) are organic compounds based on fused aromatic rings, and are formed in a variety of astrophysical, solar nebula and planetary processes. Polycyclic aromatic hydrocarbons are known or suspected to occur in a wide variety of planetary settings including icy satellites, Titan’s hazes, carbonaceous meteorites, comet nuclei, ring particles; and terrestrial organic-rich lithologies such as coals, asphaltites, and bituminous sands. Relatively few measurements of the visible and near-infrared spectra of PAHs exist, yet this wavelength region (350-2500 nm) is widely used for remote sensing. This study presents detailed analyses of the 350-2500 nm reflectance spectra of 47 fine-grained powders of different high-purity solid-state PAHs. Spectral properties of PAHs change with variations in the number and connectivity of linked aromatic rings and the presence and type of side-groups and heterocycles. PAH spectra are characterized by three strong features near ∼880 nm, ∼1145 nm, and ∼1687 nm due to overtones of νCH fundamental stretching vibrations. Some PAHs are amenable to remote detection due to the presence of diagnostic spectral features, including: Nsbnd H stretching overtones at 1490-1515 nm in NH- and NH2-bearing PAHs, aliphatic or saturated bond Csbnd H overtone vibrations at ∼1180-1280 nm and ∼1700-1860 nm; a broad asymmetric feature between ∼1450 nm and ∼1900 nm due to Osbnd H stretching overtones in aromatic alcohols, Csbnd H and Cdbnd O combinations near ∼2000-2010 nm and ∼2060-2270 nm in acetyl and carboxyl-bearing PAHs. Other substituents such as sulphonyl, thioether ether and carboxyl heterocycles, or cyano, nitrate, and aromatic side groups, do not produce well-resolved diagnostic spectral features but do cause shifts in the positions of the aromatic Csbnd H vibrational overtone features. Fluorescence is commonly suppressed by the presence of heterocycles, side-groups and in many non-alternant PAHs

  2. Use of the Moon for spacecraft calibration over 350-2500 nm

    USGS Publications Warehouse

    Kieffer, H.H.; Anderson, J.M.

    1998-01-01

    The Moon is the only natural object outside the Earth's atmosphere that is within the dynamic range of most imaging instruments on Earth-orbiting spacecraft. The excellent photometric stability of the Lunar surface will allow its use as a long-term instrument calibration source once the dependence of Lunar spectral radiance on phase and libration angles are well characterized. A program to provide this characterization is underway. Observations are being made in 23 bands within 350-950 nm, 7 of which correspond closely with spacecraft instrument bands. Observations in nine bands within 950-2500 nm began recently. Although at this time the absolute Lunar radiance model is preliminary and uncertainties are larger than most instrument calibration goals, changes in spacecraft instrument sensitivity can be precisely monitored and absolute calibration can be applied retroactively as the accuracy of the Lunar spectral radiance model improves. Several space-based imaging systems have already begun using the Moon for calibration and the EOS AM-1 platform will make periodic attitude maneuvers for Lunar and space calibration.

  3. DEIMOS: a beamline dedicated to dichroism measurements in the 350-2500 eV energy range.

    PubMed

    Ohresser, P; Otero, E; Choueikani, F; Chen, K; Stanescu, S; Deschamps, F; Moreno, T; Polack, F; Lagarde, B; Daguerre, J-P; Marteau, F; Scheurer, F; Joly, L; Kappler, J-P; Muller, B; Bunau, O; Sainctavit, Ph

    2014-01-01

    The DEIMOS (Dichroism Experimental Installation for Magneto-Optical Spectroscopy) beamline was part of the second phase of the beamline development at French Synchrotron SOLEIL (Source Optimisée de Lumière à Energie Intermédiaire du LURE) and opened to users in March 2011. It delivers polarized soft x-rays to perform x-ray absorption spectroscopy, x-ray magnetic circular dichroism, and x-ray linear dichroism in the energy range 350-2500 eV. The beamline has been optimized for stability and reproducibility in terms of photon flux and photon energy. The main end-station consists in a cryo-magnet with 2 split coils providing a 7 T magnetic field along the beam or 2 T perpendicular to the beam with a controllable temperature on the sample from 370 K down to 1.5 K.

  4. Effect of Palagonite Dust Deposition on the Automated Detection of Carbonate Vis/NIR Spectra

    NASA Technical Reports Server (NTRS)

    Gilmore, Martha S.; Merrill, Matthew D.; Castano, Rebecca; Bornstein, Benjamin; Greenwood, James

    2004-01-01

    Currently Mars missions can collect more data than can be returned. Future rovers of increased mission lifetime will benefit from onboard autonomous data processing systems to guide the selection, measurement and return of scientifically important data. One approach is to train a neural net to recognize spectral reflectance characteristics of minerals of interest. We have developed a carbonate detector using a neural net algorithm trained on 10,000 synthetic Vis/NIR (350-2500 nm) spectra. The detector was able to correctly identify carbonates in the spectra of 30 carbonate and noncarbonate field samples with 100% success. However, Martian dust coatings strongly affect the spectral characteristics of surface rocks potentially masking the underlying substrate rock. In this experiment, we measure Vis/NIR spectra of calcite coated with different thicknesses of palagonite dust and evaluate the performance of the carbonate detector.

  5. New Absorption Spectra of CH_2 Near 780 NM

    NASA Astrophysics Data System (ADS)

    Xin, Ju; Wang, Zhong; Sears, Trevor J.

    2009-06-01

    The near infrared and visible spectrum (tilde{b}^1B_1 - tilde{a}^1A_1) of singlet CH_2 has been the subject of much study. However, the region between the red end of the visible part of the spectrum and about 800 nm has not been recorded since the pioneering work of Herzberg and Johns. We have remeasured the absorption spectrum between approximately 769 and 806 nm at near shot-noise-limited sensitivity and Doppler-limited resolution using a frequency-modulated extended cavity diode laser source. Rotational branches in 7 vibronic bands involving K_a = 0-4 have been assigned using known ground state combination differences. Most of them have not previously been observed and some reassignments of the Herzberg and Johns analysis have been made. Comparison with the most complete available calculated ro-vibronic energy level structure helped considerably in making the assignments, and the observed vibronic levels are assigned to levels of both tilde{a} and tilde{b} electronic character. The calculated energy levels show moderate, up to 10 cm^{-1}, apparently random, differences from the observed levels The new data will certainly help to refine the singlet potential and also provide additional avenues for future kinetics and dynamics studies of the radical. G. Herzberg and J. W. C. Johns Proc. R. Soc. London Ser. A, 295, 107 (1966) J. -P. Gu, G. Hirsch, R J Buenker, M. Brumm, G. Osmann, P. R. Bunker and P. Jensen J. Molec. Struc., 517-8, 247 (2000) Acknowledgments: Work at Brookhaven National Laboratory was carried out under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Ju Xin acknowledges support from the Faculty and Student Teams program of the Educational Programs Department at Brookhaven National Laboratory.

  6. Ultra-broadband gain spectra of Co2+-doped fiber pumped at 1200 nm

    NASA Astrophysics Data System (ADS)

    Li, Guishun; Zhang, Chaomin; Zhu, Pengfei; Jiang, Chun; Song, Pei; Zhu, Kun

    2016-05-01

    This work investigates the energy levels, transition configuration and numerical model of Co2+-doped glass-ceramics fiber. A quasi-three-level system is employed to model the gain spectra of the doped fiber, and the rate and the power propagation equations are solved to analyze the effect of the fiber length, active ion concentration, pumping power as well as ambient temperature on the spectra. It is shown that the fiber has ultra-broadband gain spectra in 1.25-2.00 μm range via the 1200 nm pump, which is promising for full-band fiber amplifiers.

  7. Daylight spectra of individual lightning flashes in the 370-690 nm region

    NASA Technical Reports Server (NTRS)

    Orville, R. E.

    1980-01-01

    An optical multichannel analyzer slit spectrometer coupled to a minicomputer was used to record lightning spectra. This is the first successful application of a slit spectrometer to the study of individual lightning flashes and it was accomplished in the daytime. Over 300 spectra were obtained in 1978 and 1979 and are correlated with other experiments in the Thunderstorm Research International Program (TRIP). The spectra duplicate previously published nighttime data but reveal for the first time the relative intensity of H-alpha (656.3 nm) and H-beta (486.1 nm) emissions above their daytime absorption features. These are the characteristic Fraunhofer C and F lines in the solar spectrum. This result suggests that the observation of lightning from space may be accomplished by monitoring the hydrogen emissions from lightning which occur on earth, or on other planets with hydrogen in their atmospheres, such as Jupiter and Venus where lightning recently has been reported.

  8. A Sounding Rocket Mission Concept to Acquire High-Resolution Radiometric Spectra Spanning the 9 nm - 31 nm Wavelength Range

    NASA Technical Reports Server (NTRS)

    Krause, L. Habash; Cirtain, Jonathan; McGuirck, Michael; Pavelitz, Steven; Weber, Ed.; Winebarger, Amy

    2012-01-01

    When studying Solar Extreme Ultraviolet (EUV) emissions, both single-wavelength, two- dimensional (2D) spectroheliograms and multi-wavelength, one-dimensional (1D) line spectra are important, especially for a thorough understanding of the complex processes in the solar magnetized plasma from the base of the chromosphere through the corona. 2D image data are required for a detailed study of spatial structures, whereas radiometric (i.e., spectral) data provide information on relevant atomic excitation/ionization state densities (and thus temperature). Using both imaging and radiometric techniques, several satellite missions presently study solar dynamics in the EUV, including the Solar Dynamics Observatory (SDO), Hinode, and the Solar-Terrestrial Relations Observatory (STEREO). The EUV wavelengths of interest typically span 9 nm to 31 nm, with the shorter wavelengths being associated with the hottest features (e.g., intense flares and bright points) and the longer wavelengths associated with cooler features (e.g., coronal holes and filaments). Because the optical components of satellite instruments degrade over time, it is not uncommon to conduct sounding rocket underflights for calibration purposes. The authors have designed a radiometric sounding rocket payload that could serve as both a calibration underflight for and a complementary scientific mission to the upcoming Solar Ultraviolet Imager (SUVI) mission aboard the GOES-R satellite (scheduled for a 2015 launch). The challenge to provide quality radiometric line spectra over the 9-31 nm range covered by SUVI was driven by the multilayer coatings required to make the optical components, including mirrors and gratings, reflective over the entire range. Typically, these multilayers provide useful EUV reflectances over bandwidths of a few nm. Our solution to this problem was to employ a three-telescope system in which the optical components were coated with multilayers that spanned three wavelength ranges to cover

  9. Remote Raman spectra of benzene obtained from 217 meters using a single 532 nm laser pulse.

    PubMed

    Chen, Teng; Madey, John M J; Price, Frank M; Sharma, Shiv K; Lienert, Barry

    2007-06-01

    This report describes a mobile Raman lidar system that has been developed for spectral measurements of samples located remotely at ranges of hundreds of meters. The performance of this system has been quantitatively verified in a lidar calibration experiment using a hard target of standardized reflectance. A new record in detection range was achieved for remote Raman systems using 532 nm laser excitation. Specifically, Raman spectra of liquid benzene were measured with an integration time corresponding to a single 532 nm laser pulse at a distance of 217 meters. The single-shot Raman spectra at 217 meters demonstrated high signal-to-noise ratio and good resolution sufficient for the unambiguous identification of the samples of interest. The transmitter consists of a 20 Hz Nd:YAG laser emitting at 532 nm and 1064 nm and a 178 mm telescope through the use of which allows the system to produce a focused beam at the target location. The receiver consists of a large custom telescope (609 mm aperture) and a Czerny-Turner monochromator equipped with two fast photomultiplier tubes. PMID:17650374

  10. New rotationally resolved spectra of Pluto-Charon from 350 - 900 nm

    NASA Astrophysics Data System (ADS)

    Throop, Henry B.; Grundy, Will; Olkin, Cathy B.; Young, Leslie A.; Sickafoose, Amanda A.

    2015-11-01

    We are using the 11-meter Southern African Large Telescope (SALT) to acquire high-resolution rotationally resolved visible spectra of Pluto-Charon. We use the Robert Stobie Spectrograph (RSS) to observe Pluto-Charon from 350 nm to 900 nm. At 500 nm, resolution is 0.05 nm (R ~ 10,0000) and SNR per spectral resolution element is ~ 500.We planned observations for 13 dates during June-September 2014, and 13 more dates during June-September 2015. The observations for each season were spaced so as to equally sample Pluto's 6.5-day rotational period. As of the abstract submission, we have data from 11 nights (2014) and 9 nights (2015) in hand. Most of the observations were taken with observations of solar-type star HD 146233 to determine the surface reflectivity.Our results will provide constraint on the composition and spatial distribution of material on Pluto's surface, enabling comparison to previous epochs and near-infrared results, and giving a ground-truth for New Horizons' July 2015 flyby. In addition, our data will allow us to search for new spectral features in the range 350 nm to 600 nm, at a sensitivity substantially higher than previously published searches.

  11. Lightning spectra in the 850- to 1400-nm near-infrared region

    SciTech Connect

    Weidman, C. ); Boye, A. ); Crowell, L. )

    1989-09-30

    Lightning spectra in the 850- to 1400-nm near-infrared region have been recorded with 200- to 300-ms time resolution using a slitless spectrometer with a lead sulfide detector. Except for the wire portion of triggered discharge channels, rocket triggered and natural return stroke spectra are very similar. The following neutral atomic nitrogen (N I) and oxygen (O I) multiplet emissions have been identified (the wavelength, in nanometers, of the brightest line in each group is shown in parentheses): N I(2) (821.6), O I(4) (844.6), N I(1) (868.0), N I(15) (906.1), O I(8) (926.6), N I(7) (939.3), N I(19) (986.2), N I(18) (1011.3), N I(28) (1053.9), and N I(36) (1246.8). Continuum emissions with peak intensities at least an order of magnitude less than the strongest line emissions were detected. A laboratory arc simulation of return stroke discharge produced a near-IR spectrum containing all the features emitted by lightning. Addition N I radiation peaks at 1131.4 nm (N I(17)) and 1358.1 nm on the arc spectra overlapped water vapor absorption bands were not visible on lightning spectra recorded at 2.2-km range. A time-averaged lightning channel temperature of about 16,000{degree}K was calculated from the ratio of relative intensities of the N I(1) and N I(18) multiplets. {copyright} American Geophysical Union 1989

  12. Leaf Level Chlorophyll Fluorescence Emission Spectra: Narrow Band versus Full 650-800 nm Retrievals

    NASA Astrophysics Data System (ADS)

    Middleton, E.; Zhang, Q.; Campbell, P. K.; Huemmrich, K. F.; Corp, L.; Cheng, Y.

    2012-12-01

    Recently, chlorophyll fluorescence (ChlF) retrievals in narrow spectral regions (< 1 nm, between 750-770 nm) of the near infrared (NIR) region of Earth's reflected radiation have been achieved from satellites, including the Japanese GOSAT and the European Space Agency's Sciamachy/Envisat. However, these retrievals sample the total full-spectrum ChlF and are made at non-optimal wavelengths since they are not located at the peak fluorescence emission features. We wish to estimate the total full-spectrum ChlF based on emissions obtained at selected wavelengths. For this, we drew upon leaf emission spectra measured on corn leaves obtained from a USDA experimental cornfield in MD (USA). These emission spectra were determined for the adaxial and abaxial (i.e., top and underside) surfaces of leaves measured throughout the 2008 and 2011 growing seasons (n>400) using a laboratory instrument (Fluorolog-3, Horiba Scientific, USA), recorded in either 1 nm or 5 nm increments with monochromatic excitation wavelengths of either 532 or 420 nm. The total ChlF signal was computed as the area under the continuous spectral emission curves, summing the emission intensities (counts per second) per waveband. The individual narrow (1 or 5 nm) waveband emission intensities were linearly related to full emission values, with variable success across the spectrum. Equations were developed to estimate total ChlF from these individual wavebands. Here, we report the results for the average adaxial/abaxial emissions. Very strong relationships were achieved for the relatively high fluorescence intensities at the red chlorophyll peak, centered at 685 nm (r2= 0.98, RMSE = 5.53 x 107 photons/s) and in the nearby O2-B atmospheric absorption feature centered at 688 nm (r2 = 0.94, RMSE = 4.04 x 107), as well as in the far-red peak centered at 740 nm (r2=0.94, RMSE = 5.98 x107). Very good retrieval success occurred for the O2-A atmospheric absorption feature on the declining NIR shoulder centered at 760

  13. An investigation of the 661.3 nm diffuse interstellar band in Cepheid spectra

    NASA Astrophysics Data System (ADS)

    Kashuba, S. V.; Andrievsky, S. M.; Chekhonadskikh, F. A.; Luck, R. E.; Kovtyukh, V. V.; Korotin, S. A.; Krełowski, J.; Galazutdinov, G. A.

    2016-09-01

    We have investigated the diffuse interstellar band (DIB) at 661.3 nm seen in the spectra of Cepheid stars. After removal of the blending lines of ionized yttrium and neutral iron, we determined the equivalent widths (EWs) of the DIB and used these values to investigate the E(B - V)-DIB EW relation. The relation found from Cepheids matches that found in B stars. This relation can help to find the reddening for newly discovered Cepheids without extensive photometric data, and thus determine their distances. The relation between E(B - V) and the DIB EW does not yield precise reddening values. It is not a substitute for better photometric or spectroscopic methods. At best, it is indicative, but it provides some information that may not be otherwise available. Defining R* = E(B - V)/DIB EW, which we consider to be the analogue of R = E(B - V)/Av, we investigated the Galactic longitudinal dependence of R* assuming that the DIB EW value is representative of the interstellar absorption Av. We found that there is an apparent increase of the R* value that corresponds to the abnormal absorption seen towards Cygnus constellation. Finally, we constructed a 2D map of the DIB EW distribution in the Galactic disc basing on our rather limited sample of 253 spectra of 176 Cepheids.

  14. The red edge in arid region vegetation: 340-1060 nm spectra

    NASA Technical Reports Server (NTRS)

    Ray, Terrill W.; Murray, Bruce C.; Chehbouni, A.; Njoku, Eni

    1993-01-01

    -cellulose absorptions at 2090 nm and 2300 nm. Ray et al. detected absorption at 2100 nm in AVIRIS spectra of an abandoned field known to be covered by a great deal of dead plant litter. In order to better study arid region vegetation remote sensing data, it is necessary to better characterize the reflectance spectra of in situ, living, arid region plants.

  15. Recalibration of the absorption/photodissociation spectra of CO and its isotopes between 91 and 115 nm

    NASA Technical Reports Server (NTRS)

    Eidelsberg, M.; Benayoun, J. J.; Viala, Y.; Rostas, F.; Smith, P. L.; Yoshino, K.; Stark, G.; Shettle, C. A.

    1992-01-01

    A systematic error has been identified in the wavelengths and wavenumbers presented in two papers concerning the absorption/dissociation spectra of CO and isotopes between 91.2 and 115.2 nm. The published wavelengths are about 10 mA (0.001 nm) too small for lines in the 91-100 nm range. A table of corrected band origins is provided.

  16. Laboratory absorption spectra of molecules at interstellar cloud temperatures - First measurements on CO at about 97 nm

    NASA Technical Reports Server (NTRS)

    Smith, P. L.; Yoshino, K.; Stark, G.; Ito, K.; Stevens, M. H.

    1991-01-01

    In the 91-100 nm spectral region, where absorption of photons by interstellar CO usually leads to dissociation, laboratory spectra obtained at 295 K show that most CO bands are both overlapped and perturbed. Reliable band oscillator strengths cannot be extracted from such spectra. As a consequence, synthetic extreme-ultraviolet absorption spectra for CO at the low temperatures that prevail in interstellar clouds are uncertain. A supersonic expansion technique has been used to cool CO to 30 K and three bands in the 97-nm region have been studied with high spectral resolution. The measured spectrum at 30 K is in reasonable agreement with some published modeled spectra, but the ratios of integrated cross sections are somewhat different from those determined from low resolution spectra obtained at 295 K, in which the bands are blended.

  17. Comparative ultraviolet action spectra (254-320 nm) of five wild-type eukaryotic microorganisms and Escherichia coli

    SciTech Connect

    Calkins, J.; Wheeler, J.S.; Keller, C.I.; Colley, E.; Hazle, J.D.

    1988-05-01

    The action spectra of five eukaryotic organisms and the prokaryote, Escherichia coli, were examined over the wavelength range, 254-320 nm. Both the repair competent and three repair defective strains (E. coli, Caenorhabditis elegans, Saccharomyces) were examined. Tetrahymena pyriformis action spectra were performed with and without the excision repair inhibitor caffeine present. Others have observed that lethality, mutation, and the production of pyrimidine dimers show much the same wavelength dependence as DNA absorption. The results presented here demonstrate several action spectra which deviate from the DNA absorption spectra. Ultraviolet sensitization ratios (repair competent/repair defective) were also examined and were shown to change over the wavelength range. These findings suggest that DNA may not be the only important chromophore leading to cell death in the uv wavelength range studied. Since uv-B is of major importance in solar uv damage, these findings may also yield important implications for solar uv studies.

  18. Comparison of HITRAN Calculated Spectra with Laboratory Measurements of the 820, 940, 1130, and 1370 nm Water Vapor Bands

    NASA Technical Reports Server (NTRS)

    Giver, Lawrence P.; Pilewskie, P.; Gore, Warren J.; Freedman, R. S.; Chackerian, C., Jr.; Varanasi, P.

    2001-01-01

    Several groups have recently been working to improve the near-infrared spectrum of water vapor on HITRAN. The unit-conversion errors found by Giver, et al have now been corrected on the recently released HITRAN-2000. The most important aspect of this article for atmospheric absorption was increasing all the HITRAN-1996 intensities of the 940 nm band by nearly 15%. New intensity measurements of this band by Brown, et al (submitted to J. Mol. Spec.) have now been included in the latest HITRAN. However, Belmiloud, et al discuss new data in the 633-1175 nm region which they expect will substantially increase the calculated absorption of solar radiation by water vapor. They suggest the 4 bands at 725, 820, 940, and 1130 nm are all stronger than the sum of the line intensities currently on HITRAN. For the 725 and 820 nm bands, their recommended intensity increases are 10% and 15%, about the same as previously noted by Grossmann and Browell and Ponsardin and Browell. Belmiloud, et al only suggest a 6% increase for the 940 nm. band over the corrected HITRAN-1996 intensities, but a large 38% increase for the 1130 nm band. The new data discussed by Belmiloud, et al have now been published in greater detail by Schermaul, et al. The intensity increase for the 1130 nm band discussed by Belmiloud, et al is very substantial; it is important to quickly determine if the HITRAN intensity values are in error by as much as they claim. Only intensity errors for the strong lines could result in the total band intensity being in error by such a large amount. To quickly get a number of spectra of the entire near-infrared region from 650 to 1650 nm, we used the Solar Spectral Flux Radiometer with our 25-meter base path White absorption cell. This moderate resolution spectrometer is a flight instrument that has flown on the Sandia Twin Otter for the ARESE 11 experiment. The measured band profiles were then compared to calculated spectra using the latest HITRAN line intensities, convolved

  19. Atlas of reflectance spectra of terrestrial, lunar and meteoritic powders and frosts from 92 to 1800 nm

    NASA Technical Reports Server (NTRS)

    Wagner, Jeffrey; Hapke, Bruce; Wells, Eddie

    1987-01-01

    The reflectance spectra of powdered samples of selected minerals, meteorites, lunar materials and frosts are presented as an aid in the interpretation of present and future remote sensing data of solar system objects. Spectra obtained in separate wavelength regions have been combined and normalized, yielding coverage from 92 to 1800 nm. Spectral features include reflectance maxima in the far UV region produced by valence-conduction interband transitions, and reflectance minima in the near UV, visible and near IR regions, produced by charge transfer and crystal field transitions. Specific maxima and minima are diagnostic of mineral type and composition; additionally, the minerals present in mixtures such as meteorites and lunar samples can be determined.

  20. Atlas of reflectance spectra of terrestrial, lunar, and meteoritic powders and frosts from 92 to 1800 nm

    NASA Technical Reports Server (NTRS)

    Wagner, Jeffrey K.; Hapke, Bruce W.; Wells, Eddie N.

    1987-01-01

    The spectra of samples of several powder and frost materials are presented to serve in a reference database for future far-UV scans of solar system bodies. The spectra cover in the 92-1800 nm wavelengths, i.e., wavenumbers 110,000-5600/cm and photon energies from 13.5-1.5 eV. Preparation procedures for the particulates are delineated. The survey includes feldspars, orthopyroxenes, clinopyroxenes, olivines, assorted minerals, achondrites, carbonaceous chondrites and ordinary chondrites, lunar soils and rocks. Frosts of H2O, CO2, NH3 and SO2 gases were also examined. The data are expected to aid in obtaining spectral matches for asteroids and meteoroids when far-UV telescopy of solar system bodies is performed.

  1. Coincidence in the two-photon spectra of Li and Li2 at 735 nm

    NASA Astrophysics Data System (ADS)

    DeGraffenreid, W.; Sansonetti, Craig J.

    2005-02-01

    A coincidence between the 22S1/2-32S1/2 two-photon transition in the atomic spectrum of 6Li and the X 1Σ+g→ E 1Σ+g two-photon ro-vibrational series of 7Li2 was observed near 735 nm in a heat pipe oven using a tunable laser and thermionic diode detection scheme. The molecular transition obscures one component of the 6Li atomic transition. Selective detection of the atomic transition was obtained by adding an intensity-modulated laser that drives atoms from the 3S to 16P state. The coincident molecular transition and four nearby molecular lines were identified using previously determined Dunham coefficients.

  2. The role of particle size in the laboratory reflectance spectra of pyroxenes: The case of the 670-nm minor feature

    NASA Astrophysics Data System (ADS)

    Mancarella, Francesca; Orofino, Vincenzo; Blanco, Armando; D'Elia, Marcella; Fonti, Sergio

    2015-11-01

    Reflectance spectroscopy is a very helpful tool for remote sensing investigations and has been widely used in terrestrial as well as planetary observations to study the surface composition. From this perspective, the visible (Vis) and near-infrared (NIR) regions of the spectrum, where several diagnostic absorption features of minerals are located, are well suited for the identification of such materials, in particular of rock-forming silicates. Among them, pyroxenes, which have been discovered on the surface of a number of different solar system bodies, play an important role. Up to now, both laboratory and remote sensing spectroscopic studies have been focused mainly on the two major bands at about 1 and 2 μm (the so-called Band I and Band II, respectively), while little attention has been paid to the minor bands falling in the visible range. One of the most important of them, present in many pyroxenes as well as in olivines, is the weak feature (reflectance minimum) near 670 nm, generally characterized by its variable wings (reflectance maxima) at about 570 nm and 720 nm. The intensity and the exact position of this feature depend on the type of pyroxene as well as on the grain size of the particles under consideration. In this work we present the Vis/NIR experimental reflectance spectra concerning enstatite and diopside, which are excellent representative of Low Calcium Pyroxenes (typically orthopyroxenes), and High Calcium Pyroxenes (typically clinopyroxenes) respectively. The results are very interesting and show a good correlation between the grain size of our samples and the relative intensities of the reflectance maxima occurring on both sides of the 670 nm feature. A similar study performed on Acfer 353, a pyroxene-rich eucritic meteorite of the Howardite-Eucrite-Diogenite family, of putative Vestan origin, shows that also in this case the variability in the Vis region of the spectra is linked to the grain size of the meteoritic particles. The connection

  3. High-resolution spectra and photoabsorption coefficients for carbon monoxide absorption bands between 94.0 nm and 100.4 nm

    NASA Technical Reports Server (NTRS)

    Yoshino, K.; Stark, G.; Smith, P. L.; Parkinson, W. H.; Ito, K.

    1988-01-01

    Photoabsorption coefficients have been measured for the CO in interstellar clouds at a resolving power more than 20 times greater than previously obtainable. In order to facilitate comparisons, these data have been integrated over the same wavelength ranges as used in Letzelter et al. (1987). It is found that most of the results obtained for bands between 94.0 and 100.4 nm are larger than those of Letzelter; the discrepancy may be attributable to the difference between the resolving powers of the spectrometers used, because the saturation effects associated with low resolution can underestimate absorption coefficient values.

  4. Saturn's icy satellites investigated by Cassini-VIMS. I. Full-disk properties: 350-5100 nm reflectance spectra and phase curves

    USGS Publications Warehouse

    Filacchione, G.; Capaccioni, F.; McCord, T.B.; Coradini, A.; Cerroni, P.; Bellucci, G.; Tosi, F.; D'Aversa, E.; Formisano, V.; Brown, R.H.; Baines, K.H.; Bibring, J.-P.; Buratti, B.J.; Clark, R.N.; Combes, M.; Cruikshank, D.P.; Drossart, P.; Jaumann, R.; Langevin, Y.; Matson, D.L.; Mennella, V.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, C.; Hansen, G.; Hibbitts, K.; Showalter, M.; Newman, S.

    2007-01-01

    Saturn's icy satellites are among the main scientific objectives of the Cassini-VIMS (Visual and Infrared Mapping Spectrometer) experiment. This paper contains a first systematic and comparative analysis of the full-disk spectral properties of Dione, Enceladus, Epimetheus, Hyperion, Iapetus, Mimas, Phoebe, Rhea and Tethys as observed by VIMS from July 2004 to June 2005. The disk integrated properties (350-5100 nm reflectance spectra and phase curves at 550-2232 nm) and images of satellites are reported and discussed in detail together with the observed geometry. In general, the spectra in the visible spectral range are almost featureless and can be classified according to the spectral slopes: from the bluish Enceladus and Phoebe to the redder Iapetus, Hyperion and Epimetheus. In the 1000-1300 nm range the spectra of Enceladus, Tethys, Mimas and Rhea are characterized by a negative slope, consistent with a surface largely dominated by water ice, while the spectra of Iapetus, Hyperion and Phoebe show a considerable reddening pointing out the relevant role played by darkening materials present on the surface. In between these two classes are Dione and Epimetheus, which have a flat spectrum in this range. The main absorption bands identified in the infrared are the 1520, 2020, 3000 nm H2O/OH bands (for all satellites), although Iapetus dark terrains show mostly a deep 3000 nm band while the 1520 and 2020 nm bands are very faint. In this spectral range, the Iapetus spectrum is characterized by a strong reddening. The CO2 band at 4260 nm and the Fresnel ice peak around 3100 nm are evident only on Hyperion, Phoebe and Iapetus. The phase curves at 550 and at 2232 nm are reported for all the available observations in the 0??-144?? range; Rhea shows an opposition surge at visible wavelengths in the 0.5??-1.17?? interval. The improvement on the retrieval of the full-disk reflectance spectra can be appreciated by a direct comparison with ground-based telescopic data available

  5. Direct on-strip analysis of size- and time-resolved aerosol impactor samples using laser induced fluorescence spectra excited at 263 and 351 nm.

    PubMed

    Wang, Chuji; Pan, Yong-Le; James, Deryck; Wetmore, Alan E; Redding, Brandon

    2014-04-11

    We report a novel atmospheric aerosol characterization technique, in which dual wavelength UV laser induced fluorescence (LIF) spectrometry marries an eight-stage rotating drum impactor (RDI), namely UV-LIF-RDI, to achieve size- and time-resolved analysis of aerosol particles on-strip. The UV-LIF-RDI technique measured LIF spectra via direct laser beam illumination onto the particles that were impacted on a RDI strip with a spatial resolution of 1.2mm, equivalent to an averaged time resolution in the aerosol sampling of 3.6 h. Excited by a 263 nm or 351 nm laser, more than 2000 LIF spectra within a 3-week aerosol collection time period were obtained from the eight individual RDI strips that collected particles in eight different sizes ranging from 0.09 to 10 μm in Djibouti. Based on the known fluorescence database from atmospheric aerosols in the US, the LIF spectra obtained from the Djibouti aerosol samples were found to be dominated by fluorescence clusters 2, 5, and 8 (peaked at 330, 370, and 475 nm) when excited at 263 nm and by fluorescence clusters 1, 2, 5, and 6 (peaked at 390 and 460 nm) when excited at 351 nm. Size- and time-dependent variations of the fluorescence spectra revealed some size and time evolution behavior of organic and biological aerosols from the atmosphere in Djibouti. Moreover, this analytical technique could locate the possible sources and chemical compositions contributing to these fluorescence clusters. Advantages, limitations, and future developments of this new aerosol analysis technique are also discussed.

  6. Direct on-strip analysis of size- and time-resolved aerosol impactor samples using laser induced fluorescence spectra excited at 263 and 351 nm.

    PubMed

    Wang, Chuji; Pan, Yong-Le; James, Deryck; Wetmore, Alan E; Redding, Brandon

    2014-04-11

    We report a novel atmospheric aerosol characterization technique, in which dual wavelength UV laser induced fluorescence (LIF) spectrometry marries an eight-stage rotating drum impactor (RDI), namely UV-LIF-RDI, to achieve size- and time-resolved analysis of aerosol particles on-strip. The UV-LIF-RDI technique measured LIF spectra via direct laser beam illumination onto the particles that were impacted on a RDI strip with a spatial resolution of 1.2mm, equivalent to an averaged time resolution in the aerosol sampling of 3.6 h. Excited by a 263 nm or 351 nm laser, more than 2000 LIF spectra within a 3-week aerosol collection time period were obtained from the eight individual RDI strips that collected particles in eight different sizes ranging from 0.09 to 10 μm in Djibouti. Based on the known fluorescence database from atmospheric aerosols in the US, the LIF spectra obtained from the Djibouti aerosol samples were found to be dominated by fluorescence clusters 2, 5, and 8 (peaked at 330, 370, and 475 nm) when excited at 263 nm and by fluorescence clusters 1, 2, 5, and 6 (peaked at 390 and 460 nm) when excited at 351 nm. Size- and time-dependent variations of the fluorescence spectra revealed some size and time evolution behavior of organic and biological aerosols from the atmosphere in Djibouti. Moreover, this analytical technique could locate the possible sources and chemical compositions contributing to these fluorescence clusters. Advantages, limitations, and future developments of this new aerosol analysis technique are also discussed. PMID:24745745

  7. [Study on Paddy Soil Chronosequences Based on Visiblc-Near Infrared Diffuse Reflectance Spectra].

    PubMed

    Wu, Deng-wei; Zhang, Gan-lin

    2015-12-01

    To investigate spectral characteristics of different soil compositions, eight soil profiles from two paddy soil chronosequences developed on red clays and red sandstones respectively were collected in Jiangxi Province. A total of 37 soil samples were taken from each soil horizons of the profiles. The paddy soil chronosequences were chosen mainly because all soil profiles have the same land management and thus parent materials and rice cultivation time would be two major soil formative factors. This makes it possible to study spectral response characteristics of soil organic matter (SOM) and parent material characteristics. We measured diffuse reflectance spectra data of soil samples using the Cary 5000 spectrophotometer at 350-2500 nm spectral range. Spectral response characteristics of SOM and inorganic minerals in paddy soils were analyzed according to different soil horizons, soil forming times and parent materials. Experiment results showed that for soil samples from a single parent material, overall reflectance presented by PC_1 score can be calibrated for soil organic matter (SOM) content with high precision (R(RC)² = 0.91, R(RS)² = 0.79), even though the SOM content was low (not more than 20 g · kg⁻¹). The absorption strength (AS) at 1400, 1900 and 2200 nm was mainly affected by the minerals inherited from parent materials. And the more the sample was near to bottom of a soil profile, the higher the AS value. Samples with the same mineral components had the similar AS ratio among these three wavelength locations. The differences in parent materials can significantly affect spectral curve shape and spectral absorption strength. To make the calibration more interpretative, parent material factors should be considered. PMID:26964213

  8. Detection of water vapour absorption around 363nm in measured atmospheric absorption spectra and its effect on DOAS evaluations

    NASA Astrophysics Data System (ADS)

    Lampel, Johannes; Polyansky, Oleg. L.; Kyuberis, Alexandra A.; Zobov, Nikolai F.; Tennyson, Jonathan; Lodi, Lorenzo; Pöhler, Denis; Frieß, Udo; Platt, Ulrich; Beirle, Steffen; Wagner, Thomas

    2016-04-01

    Water vapour is known to absorb light from the microwave region to the blue part of the visible spectrum at a decreasing magnitude. Ab-initio approaches to model individual absorption lines of the gaseous water molecule predict absorption lines until its dissociation limit at 243 nm. We present first evidence of water vapour absorption at 363 nm from field measurements based on the POKAZATEL absorption line list by Polyansky et al. (2016) using data from Multi-Axis differential optical absorption spectroscopy (MAX-DOAS) and Longpath (LP)-DOAS measurements. The predicted absorptions contribute significantly to the observed optical depths with up to 2 × 10‑3. Their magnitude correlates well (R2 = 0.89) to simultaneously measured well-established water vapour absorptions in the blue spectral range from 452-499 nm, but is underestimated by a factor of 2.6 ± 0.6 in the ab-initio model. At a spectral resolution of 0.5nm this leads to a maximum absorption cross-section value of 5.4 × 10‑27 cm2/molec at 362.3nm. The results are independent of the employed cross-section data to compensate for the overlayed absorption of the oxygen dimer O4. The newly found absorption can have a significant impact on the spectral retrieval of absorbing trace-gas species in the spectral range around 363 nm. Its effect on the spectral analysis of O4, HONO and OClO are discussed.

  9. Correlated Two-Electron Momentum Spectra for Strong-Field Nonsequential Double Ionization of He at 800 nm

    SciTech Connect

    Rudenko, A.; Ergler, Th.; Zrost, K.; Feuerstein, B.; Schroeter, C. D.; Moshammer, R.; Ullrich, J.; Jesus, V. L. B. de

    2007-12-31

    We report on a kinematically complete experiment on nonsequential double ionization of He by 25 fs 800 nm laser pulses at 1.5 PW/cm{sup 2}. The suppression of the recollision-induced excitation at this high intensity allows us to address in a clean way direct (e,2e) ionization by the recolliding electron. In contrast with earlier experimental results, but in agreement with various theoretical predictions, the two-electron momentum distributions along the laser polarization axis exhibit a pronounced V-shaped structure, which can be explained by the role of Coulomb repulsion and typical (e,2e) kinematics.

  10. Sounding Rocket Observations of Active Region Soft X-Ray Spectra Between 0.5 and 2.5 nm Using a Modified SDO/EVE Instrument

    NASA Astrophysics Data System (ADS)

    Wieman, Seth; Didkovsky, Leonid; Woods, Thomas; Jones, Andrew; Moore, Christopher

    2016-10-01

    Spectrally resolved measurements of individual solar active regions (ARs) in the soft X-ray (SXR) range are important for studying dynamic processes in the solar corona and their associated effects on the Earth's upper atmosphere. They are also a means of evaluating atomic data and elemental abundances used in physics-based solar spectral models. However, very few such measurements are available. We present spectral measurements of two individual ARs in the 0.5 to 2.5 nm range obtained on the NASA 36.290 sounding rocket flight of 21 October 2013 (at about 18:30 UT) using the Solar Aspect Monitor (SAM), a channel of the Extreme Ultaviolet Variability Experiment (EVE) payload designed for underflight calibrations of the orbital EVE on the Solar Dynamics Observatory (SDO). The EVE rocket instrument is a duplicate of the EVE on SDO, except the SAM channel on the rocket version was modified in 2012 to include a freestanding transmission grating to provide spectrally resolved images of the solar disk with the best signal to noise ratio for the brightest features, such as ARs. Calibrations of the EVE sounding rocket instrument at the National Institute of Standards and Technology Synchrotron Ultraviolet Radiation Facility (NIST/SURF) have provided a measurement of the SAM absolute spectral response function and a mapping of wavelength separation in the grating diffraction pattern. We discuss techniques (incorporating the NIST/SURF data) for determining SXR spectra from the dispersed AR images as well as the resulting spectra for NOAA ARs 11877 and 11875 observed on the 2013 rocket flight. In comparisons with physics-based spectral models using the CHIANTI v8 atomic database we find that both AR spectra are in good agreement with isothermal spectra (4 MK), as well as spectra based on an AR differential emission measure (DEM) included with the CHIANTI distribution, with the exception of the relative intensities of strong Fe xvii lines associated with 2p6- 2p53{s} and 2p6- 2

  11. Properties of jet engine combustion particles during the PartEmis experiment: Particle size spectra (d > 15 nm) and volatility

    NASA Astrophysics Data System (ADS)

    Nyeki, S.; Gysel, M.; Weingartner, E.; Baltensperger, U.; Hitzenberger, R.; Petzold, A.; Wilson, C. W.

    2004-09-01

    Size distributions (d > 15 nm) and volatile properties of combustion particles were measured during test-rig experiments on a jet engine, consisting of a combustor and three simulated turbine stages (HES). The combustor was operated to simulate legacy (inlet temperature 300°C) and contemporary (500°C) cruise conditions, using kerosene with three different fuel sulfur contents (FSC; 50, 400 and 1300 μg g-1). Measurements found that contemporary cruise conditions resulted in lower number emission indices (EIN15) and higher geometric mean particle diameter (dG) than for legacy conditions. Increasing FSC resulted in an overall increase in EIN15 and decrease in dG. The HES stages or fuel additive (APA101) had little influence on EIN15 or dG, however, this is uncertain due to the measurement variability. EIN15 for non-volatile particles was largely independent of all examined conditions.

  12. HST Multicolor (255-1042 nm) Photometry of Saturn's Main Rings. 1; Radial Profiles, Phase and Opening Angle Variations, and Regional Spectra

    NASA Technical Reports Server (NTRS)

    Cuzzi, Jeffrey N.; French, Richard G.; Dones, Luke; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    The main rings of Saturn were observed with the Planetary Camera of the WFPC2 instrument on the Hubble Space Telescope (HST) from September 1996 to August 2000 as the'ring opening angle to Earth and Sun increased from 4 deg to 24 deg, with a spread of phase angles between 0.3 deg and 6 deg at each opening angle. The rings were routinely observed in the five HST wideband UBVRI filters (F336W, F439W, F555W, F675W, and F814W) and occasionally in the F255W, F785LP, and F1042M filters. The emphasis in this series of papers will be on radial color (implying compositional) variations. In this first paper we describe the analysis technique and calibration procedure, note revisions in a previously published Voyager ring color data analysis, and present new results based on over 100 HST images. In the 300-600 nm spectral range where the rings are red, the 555nm/336nm ratio increases by about 14% as the phase angle increases from 0.3 deg to 6 deg. This effect, never reported previously for the rings, is significantly larger than the phase reddening which characterizes other icy objects, primarily because of the redness of the rings. However, there is no discernible tendency for color to vary with ring opening angle at a given phase angle, and there is no phase variation of color where the spectrum is flat. We infer from this combination of facts that multiple intraparticle scattering, either in a regolith or between facets of an unusually rough surface, is important in these geometries, but that multiple interparticle scattering in a vertically extended layer is not. Voyager color ratios at a phase angle of 14 deg are compatible with this trend, but calibration uncertainties prevent their use in quantitative modeling. Overall ring-average spectra are compatible with those of earlier work within calibration uncertainties, but ring spectra vary noticeably with region. We refine and subdivide the regions previously defined by others. The variation seen between radial profiles of

  13. A table of semiempirical gf values. Part 1: Wavelengths: 5.2682 nm to 272.3380 nm. [to calculate line-blanketed model atmospheres for solar and stellar spectra

    NASA Technical Reports Server (NTRS)

    Kurucz, R. L.; Peytremann, E.

    1975-01-01

    The gf values for 265,587 atomic lines selected from the line data used to calculate line-blanketed model atmospheres are tabulated. These data are especially useful for line identification and spectral synthesis in solar and stellar spectra. The gf values are calculated semiempirically by using scaled Thomas-Fermi-Dirac radial wavefunctions and eigenvectors found through least-squares fits to observed energy levels. Included in the calculation are the first five or six stages of ionization for sequences up through nickel. Published gf values are included for elements heavier than nickel. The tabulation is restricted to lines with wavelengths less than 10 micrometers.

  14. HIGH-RESOLUTION ELECTRON-IMPACT EMISSION SPECTRA AND VIBRATIONAL EMISSION CROSS SECTIONS FROM 330-1100 nm FOR N{sub 2}

    SciTech Connect

    Mangina, Rao S.; Ajello, Joseph M.; West, Robert A.; Dziczek, Dariusz

    2011-09-01

    Electron-impact emission cross sections for N{sub 2} were measured in the wavelength range of 330-1100 nm at 25 eV and 100 eV impact energies. Cross sections of several molecular emission bands of the first positive band system B {sup 3}{Pi}{sub g} {sup +}({nu}') {yields} A {sup 3}{Sigma}{sub g} {sup +}({nu}'') and the second positive band system C {sup 3}{Pi}{sub u} ({nu}') {yields} B {sup 3}{Pi}{sub g} ({nu}'') of N{sub 2}, the first negative band (1NB) system B {sup 2}{Sigma}{sub u} {sup +}({nu}') {yields} X {sup 2}{Sigma}{sub g} {sup +}({nu}'') and Meinel band system A {sup 2}{Pi}{sub u} ({nu}') {yields} X {sup 2}{Sigma}{sub g} {sup +}({nu}'') of N{sub 2} {sup +} ions as well as line emissions of N (N I) and N{sup +} (N II) in the visible-optical-near-IR wavelength range reported in this work were measured for the first time in a single experimental setup at high spectral resolving power ({lambda}/{Delta}{lambda} {approx} 10000) under single-collision-scattering geometry and optically thin conditions. Rotational emission lines of N{sub 2} and N{sub 2} {sup +} were observed for strong emission bands at a gas temperature of about 300 K. The absolute cross section of the strongest (0,0) vibrational band at 391.43 nm of 1NB was determined using the standard H{sub {alpha}} emission cross sections of H{sub 2} by electron impact at both 25 eV and 100 eV electron-impact energies, and the cross sections for the remainder of the emissions were determined using (0,0) 1NB value. A comparison of the present emission cross sections with the earlier published data from both electron energy loss and electron-impact-induced fluorescence emission is discussed.

  15. Action spectra again?

    PubMed

    Coohill, T P

    1991-11-01

    Action spectroscopy has a long history and is of central importance to photobiological studies. Action spectra were among the first assays to point to chlorophyll as the molecule most responsible for plant growth and to DNA as the genetic material. It is useful to construct action spectra early in the investigation of new areas of photobiological research in an attempt to determine the wavelength limits of the radiation region causing the studied response. But due to the severe absorption of ultraviolet (UV) radiation by biological samples, UV action spectra were first limited to small cells (bacteria and fungi). Advances in techniques (e.g. single cell culture) and analysis allowed accurate action spectra to be reported even for mammalian cells. But precise analytical action spectra are often difficult to obtain when large, pigmented, or groups of cells are investigated. Here some action spectra are limited in interpretation and merely supply a wavelength vs effect curve. When polychromatic sources are employed, the interpretation of action spectra is even more complex and formidable. But such polychromatic action spectra can be more directly related to ambient responses. Since precise action spectra usually require the completion of a relatively large number of careful experiments using somewhat sophisticated equipment over a range of at least six wavelengths, they are often not pursued. But they remain central to the elucidation of the effect being studied. The worldwide community has agreed that stratospheric ozone is depleting, with the possibility of a consequent rise in the amount of UV-B (290-320 nm) reaching the earth's surface. It is therefore essential that new action spectra be completed for UV-B effects on a large variety of responses of human, animal, and aquatic plant systems. Combining these action spectra with the known amounts of UV-B reaching the biosphere can give rise to solar UV effectiveness spectra that, in turn, can give rise to estimates

  16. High-resolution spectra of isotopic methanes near 1645 nm

    NASA Technical Reports Server (NTRS)

    Fox, K.

    1984-01-01

    It is demonstrated that the coincidence between Er:YAG laser emission and CH4 absorption is associated with the R(8) multiplet of C-13H4 instead of the R(6) of C-12H4. The Er:YAG emission was characterized as a laser emission at 6079.4/cm with a bandwidh of 2.2/cm and overlapping CH4 emission at 6078.7/cm. The R(6) component of C-12H4 closest to 6078.7/cm is calculated to be 6077.06/cm, corresponding to an absorption coefficient (AC) of 1.12/cm per atm. The F2-prime component of R(8) of C-13H4 has an AC of 0.308/cm per atm, which corresponds well with a range of 1.2-30.30/cm per atm based on a partial pressure of 1.6/89 ppm. The Er:YAG laser is a candidate for use in spectroscopic studies of CH4 atmospheric pollutants, natural gas movement and storage and gas accumulation in coal mines.

  17. Sub-10 nm nanopantography

    NASA Astrophysics Data System (ADS)

    Tian, Siyuan; Donnelly, Vincent M.; Ruchhoeft, Paul; Economou, Demetre J.

    2015-11-01

    Nanopantography, a massively parallel nanopatterning method over large areas, was previously shown to be capable of printing 10 nm features in silicon, using an array of 1000 nm-diameter electrostatic lenses, fabricated on the substrate, to focus beamlets of a broad area ion beam on selected regions of the substrate. In the present study, using lens dimensional scaling optimized by computer simulation, and reduction in the ion beam image size and energy dispersion, the resolution of nanopantography was dramatically improved, allowing features as small as 3 nm to be etched into Si.

  18. Albuquerque, NM, USA

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Albuquerque, NM (35.0N, 106.5W) is situated on the edge of the Rio Grande River and flood plain which cuts across the image. The reddish brown surface of the Albuquerque Basin is a fault depression filled with ancient alluvial fan and lake bed sediments. On the slopes of the Manzano Mountains to the east of Albuquerque, juniper and other timber of the Cibola National Forest can be seen as contrasting dark tones of vegetation.

  19. Storm Spectra

    NASA Technical Reports Server (NTRS)

    2007-01-01

    portion is defined by the day/night boundary (known as the terminator).

    These two images illustrate only a small fraction of the information contained in a single LEISA scan, highlighting just one aspect of the power of infrared spectra for atmospheric studies.

  20. TUNABLE DIODE LASER MEASUREMENTS OF NO2 NEAR 670 NM AND 395 NM. (R823933)

    EPA Science Inventory

    Two single-mode diode lasers were used to record high-resolution absorption spectra of NO2 (dilute in Ar) near 670.2 and 394.5 nm over a range of temperatures (296 to 774 K) and total pressures (2.4 x 10(-2) to 1 atm). A commercial InGaAsP laser was tuned 1.3 cm(-1) at a repetiti...

  1. Fluorescence spectra of bioaerosols exposed to ozone in a laboratory reaction chamber to simulate atmospheric processing

    NASA Astrophysics Data System (ADS)

    Pan, Yong-Le; Hill, Steven C.; Pinnick, Ronald G.; Santarpia, Joshua L.; Baker, Neal; Alvarez, Benjamin; Ratnesar-Shumate, Shanna; Cottrell, Brian; McKee, Laura

    2011-05-01

    Laboratory measurements demonstrating the effects of ozone on aerosolized B. thuringiensis, as revealed by fluorescence spectra, are reported. The fluorescence emission peak around 330 nm (excited at 263nm) decreases somewhat in intensity and becomes slightly blue-shifted. Further, the fluorescence emission around 400 nm-550 nm is less affected by the ozone than is the 330 nm (tryptophan) peak.

  2. Negative Ion Photoelectron Spectra of Halomethyl Anions

    NASA Astrophysics Data System (ADS)

    Vogelhuber, Kristen M.; Wren, Scott W.; McCoy, Anne B.; Ervin, Kent M.; Lineberger, W. Carl

    2009-06-01

    Halomethyl anions undergo a significant geometry change upon electron photodetachment, resulting in multiple extended vibrational progressions in the photoelectron spectra. The normal mode analysis that successfully models photoelectron spectra when geometry changes are modest is unable to reproduce the experimental data using physically reasonable parameters. A three-dimensional anharmonic coupled-mode analysis was employed to accurately reproduce the observed vibrational structure. We present the 364 nm negative ion photoelectron spectra of the halomethyl anions CHX_2^- and CDX_2^- (X = Cl, Br, I) and report electron affinities, vibrational frequencies, and geometries.

  3. Near infrared Raman spectra of Rhizoma dioscoreae

    NASA Astrophysics Data System (ADS)

    Lin, Wenshuo; Chen, Rong; Chen, Guannan; Feng, Sangyuan; Li, Yongzeng; Huang, Zufang; Li, Yongsen

    2008-03-01

    A novel and compact near-infrared (NIR) Raman system is developed using 785-nm diode laser, volume-phase technology holographic system, and NIR intensified charge-coupled device (CCD). Raman spectra and first derivative spectra of Rhizoma Dioscoreae are obtained. Raman spectra of Rhizoma Dioscoreae showed three strong characteristic peaks at 477.4cm -1, 863.9cm -1, and 936.0cm -1. The major ingredients are protein, amino acid, starch, polysaccharides and so on, matched with the known basic biochemical composition of Rhizoma Dioscoreae. In the first derivative spectra of Rhizoma Dioscoreae, distinguishing characteristic peaks appeared at 467.674cm -1, 484.603cm -1, 870.37cm -1, 943.368cm -1. Contrasted with Rhizoma Dioscoreae Raman spectra, in 600cm -1 to 800cm -1, 1000cm -1 to 1400cm -1 regions, changes in Rhizoma Dioscoreae Raman first derivative spectra are represented more clearly than Rhizoma Dioscoreae Raman spectra. So Rhizoma Dioscoreae raman first derivative spectra can be an accurate supplementary analysis method to Rhizoma Dioscoreae Raman spectra.

  4. Standoff detection of biological agents using laser induced fluorescence—a comparison of 294 nm and 355 nm excitation wavelengths

    PubMed Central

    Farsund, Øystein; Rustad, Gunnar; Skogan, Gunnar

    2012-01-01

    Standoff detection measuring the fluorescence spectra of seven different biological agents excited by 294 nm as well as 355 nm wavelength laser pulses has been undertaken. The biological warfare agent simulants were released in a semi-closed aerosol chamber at 210 m standoff distance and excited by light at either of the two wavelengths using the same instrument. Significant differences in several of the agents’ fluorescence response were seen at the two wavelengths. The anthrax simulants’ fluorescence responses were almost an order of magnitude stronger at the shorter wavelength excitation. However, most importantly, the fluorescence spectra were significantly more dissimilar at 294 nm than at 355 nm excitation with ~7 nm spectral resolution. This indicates that classification of the substances should be possible with a lower error rate for standoff detection using 294 nm rather than 355 nm excitation wavelength, or even better, utilizing both. PMID:23162732

  5. Standoff detection of biological agents using laser induced fluorescence-a comparison of 294 nm and 355 nm excitation wavelengths.

    PubMed

    Farsund, Oystein; Rustad, Gunnar; Skogan, Gunnar

    2012-11-01

    Standoff detection measuring the fluorescence spectra of seven different biological agents excited by 294 nm as well as 355 nm wavelength laser pulses has been undertaken. The biological warfare agent simulants were released in a semi-closed aerosol chamber at 210 m standoff distance and excited by light at either of the two wavelengths using the same instrument. Significant differences in several of the agents' fluorescence response were seen at the two wavelengths. The anthrax simulants' fluorescence responses were almost an order of magnitude stronger at the shorter wavelength excitation. However, most importantly, the fluorescence spectra were significantly more dissimilar at 294 nm than at 355 nm excitation with ~7 nm spectral resolution. This indicates that classification of the substances should be possible with a lower error rate for standoff detection using 294 nm rather than 355 nm excitation wavelength, or even better, utilizing both. PMID:23162732

  6. Night Spectra Quest.

    ERIC Educational Resources Information Center

    Jacobs, Stephen

    1995-01-01

    Presents the Night Spectra Quest, a pocket-sized chart that identifies in color the spectra of all the common night lights and has an integrally mounted, holographic diffraction grating to look through. (JRH)

  7. Stability properties of wines by absorption spectra

    NASA Astrophysics Data System (ADS)

    Larena, A.; Vega, J.

    1986-03-01

    The temporal evolution of absorption spectra (370-700 nm) of different spanish wines has been studied by us under the influence of air presence, and the light exposition. In particular, we have exposed the wines to a magenta light. Nevertheless, the color coordinates of wine show a little relative variation (0.1-1 %)

  8. Spectra of the supernova SN1999by

    NASA Astrophysics Data System (ADS)

    Gavin, M.

    1999-08-01

    Spectra of SN1999by by Maurice Gavin. 30cm SCT+Rainbow grating+MX9 CCD; dispersion 4nm/pixel. 1999 May 2, 6, 10; 15m-35m exp. Spectrogram [at top] electronically stretched; profiles via Pixwin software.

  9. 469nm Fiber Laser Source

    SciTech Connect

    Drobshoff, A; Dawson, J W; Pennington, D M; Payne, S A; Beach, R

    2005-01-20

    We have demonstrated 466mW of 469nm light from a frequency doubled continuous wave fiber laser. The system consisted of a 938nm single frequency laser diode master oscillator, which was amplified in two stages to 5 Watts using cladding pumped Nd{sup 3+} fiber amplifiers and then frequency doubled in a single pass through periodically poled KTP. The 3cm long PPKTP crystal was made by Raicol Crystals Ltd. with a period of 5.9 {micro}m and had a phase match temperature of 47 degrees Centigrade. The beam was focused to a 1/e{sup 2} diameter in the crystal of 29 {micro}m. Overall conversion efficiency was 11% and the results agreed well with standard models. Our 938nm fiber amplifier design minimizes amplified spontaneous emission at 1088nm by employing an optimized core to cladding size ratio. This design allows the 3-level transition to operate at high inversion, thus making it competitive with the 1088nm 4-level transition. We have also carefully chosen the fiber coil diameter to help suppress propagation of wavelengths longer than 938 nm. At 2 Watts, the 938nm laser had an M{sup 2} of 1.1 and good polarization (correctable with a quarter and half wave plate to >10:1).

  10. Photographic spectra of fireballs

    NASA Astrophysics Data System (ADS)

    Borovička, J.

    2016-01-01

    Two methods of spectroscopy of meteors using image intensified video cameras and classical photographic film cameras are compared. Video cameras provide large number of low resolution spectra of meteors of normal brightness, which can be used for statistical studies. Large format film cameras have been used through the history and provide high resolution spectra, which can be used to derive temperature, density and absolute abundances of various elements in the radiating plasma. The sensitivity of films is, however, low and only spectra of bright meteors (fireballs) can be studied. Examples of photographic fireball spectra are provided.

  11. Spectra of stable sonoluminescence

    NASA Astrophysics Data System (ADS)

    Lewis, Stephen D.

    1992-12-01

    The continuous emission of picosecond pulses of light has been observed to originate from a bubble trapped at the pressure antinode of a resonant sound field in water and in water/glycerin mixtures. The spectra of this light in several solutions has been measured with a scanning monochrometer/photomultiplier detector system. The spectra are broadband and show strong emission in the UV region. A comparison of this measurement to two other independently produced spectra is made. The spectra are also modeled by a blackbody radiation distribution to determine an effective blackbody temperature and a size is deduced as if Sonoluminescence were characterized by blackbody radiation.

  12. Crack spectra analysis

    SciTech Connect

    Tiernan, M.

    1980-09-01

    Crack spectra derived from velocity data have been shown to exhibit systematics which reflect microstructural and textural differences between samples (Warren and Tiernan, 1980). Further research into both properties and information content of crack spectra have yielded the following: Spectral features are reproducible even at low pressures; certain observed spectral features may correspond to non-in-situ crack populations created during sample retrieval; the functional form of a crack spectra may be diagnostic of the sample's grain texture; hysteresis is observed in crack spectra between up and down pressure runs - it may be due to friction between the faces of closed crack populations.

  13. Extreme ultraviolet emission spectra of Gd and Tb ions

    SciTech Connect

    Kilbane, D.; O'Sullivan, G.

    2010-11-15

    Theoretical extreme ultraviolet emission spectra of gadolinium and terbium ions calculated with the Cowan suite of codes and the flexible atomic code (FAC) relativistic code are presented. 4d-4f and 4p-4d transitions give rise to unresolved transition arrays in a range of ions. The effects of configuration interaction are investigated for transitions between singly excited configurations. Optimization of emission at 6.775 nm and 6.515 nm is achieved for Gd and Tb ions, respectively, by consideration of plasma effects. The resulting synthetic spectra are compared with experimental spectra recorded using the laser produced plasma technique.

  14. Photoionization of Nitromethane at 355nm and 266nm

    NASA Astrophysics Data System (ADS)

    Martínez, Denhi; Betancourt, Francisco; Poveda, Juan Carlos; Guerrero, Alfonso; Cisneros, Carmen; Álvarez, Ignacio

    2014-05-01

    Nitromethane is one of the high-yield clean liquid fuels, i.e., thanks to the oxygen contained in nitromethane, much less atmospheric oxygen is burned compared to hydrocarbons such as gasoline, making the nitromethane an important prototypical energetic material, the understanding of its chemistry is relevant in other fields such as atmospheric chemistry or biochemistry. In this work we present the study of photoionization dynamics by multiphoton absorption with 355 nm and 266 nm wavelength photons, using time of flight spectrometry in reflectron mode (R-TOF). Some of the observed ion products appear for both wavelength and other only in one of them; both results were compared with preview observations and new ions were detected. This work is supported by CONACYT grant 165410 and DGAPA-UNAM grants IN-107-912 and IN-102-613.

  15. Raman spectra of seven interplanetary dust particles

    NASA Technical Reports Server (NTRS)

    Xu, Yin-Lin; Yu, Min; Fan, Chang-Yun

    1992-01-01

    The Raman shift spectra of seven interplanetary dust particles, U2034(F10), U2034(F8), U2022(B1), W7074 18, W7074 C15, W7074 C3 and W7074 A7, were measured with a Spex-1403 Raman spectrograph. The exciting radiations were the 488 nm and 514 nm line of a 5W argon ion laser. All seven spectra exhibit the 1350 and 1600 Delta/cm arbon bands, implying that the Interplanetary dust particles were coated with hydrocarbon and incompletely crystallized carbon, the part of which may be the residue of hydrocarbon contents in the particles after water loss by the heating during their entry into the earth's atmosphere. A weak band structure in the 520-610/cm range could be caused by cyclosilicates, and a weak band at 2900/cm is tentatively identified as due to hydrocarbon molecules.

  16. Lily Pad Spectra

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The color image on the lower left from the panoramic camera on the Mars Exploration Rover Opportunity shows the 'Lily Pad' bounce-mark area at Meridiani Planum, Mars. This image was acquired on the 3rd sol, or martian day, of Opportunity's mission (Jan.26, 2004). The upper left image is a monochrome (single filter) image from the rover's panoramic camera, showing regions from which spectra were extracted from the 'Lily Pad' area. As noted by the line graph on the right, the green spectra is from the undisturbed surface and the red spectra is from the airbag bounce mark.

  17. Electronic spectra of astrophysically interesting cations

    SciTech Connect

    Maier, John P. Rice, Corey A. Mazzotti, Fabio J. Johnson, Anatoly

    2015-01-22

    The electronic spectra of polyacetylene cations were recorded at 20K in the laboratory in an ion trap instrument. These can then be compared with diffuse interstellar band (DIB) absorptions. Examination of recently published data shows that the attribution of a weak DIB at ∼506.9 nm to diacetylene cation is not justified. Study of the higher excited electronic states of polyacetylene cations shows that their widths can still be sufficiently narrow for consideration as DIB carriers.

  18. Thermodynamic analysis of spectra

    SciTech Connect

    Mitchell, G. E.; Shriner, J. F. Jr.

    2008-04-04

    Although random matrix theory had its initial application to neutron resonances, there is a relative scarcity of suitable nuclear data. The primary reason for this is the sensitivity of the standard measures used to evaluate spectra--the spectra must be essential pure (no state with a different symmetry) and complete (no states missing). Additional measures that are less sensitive to these experimental limitations are of significant value. The standard measure for long range order is the {delta}{sub 3} statistic. In the original paper that introduced this statistic, Dyson and Mehta also attempted to evaluate spectra with thermodynamic variables obtained from the circular orthogonal ensemble. We consider the thermodynamic 'internal energy' and evaluate its sensitivity to experimental limitations such as missing and spurious levels. Monte Carlo simulations suggest that the internal energy is less sensitive to mistakes than is {delta}{sub 3}, and thus the internal energy can serve as a addition to the tool kit for evaluating experimental spectra.

  19. Sol-gel fabrication of one-dimensional photonic crystals with predicted transmission spectra

    NASA Astrophysics Data System (ADS)

    Ilinykh, V. A.; Matyushkin, L. B.

    2016-08-01

    One-dimensional multilayer structures of periodically alternating low refractive index (silica) and high refractive index (titania) materials have been deposited by sol-gel spincoating. Experimental spectra of the structures are in agreement with spectra calculated by transfer matrix technique. As an example, theoretical and experimental spectra with a stop band corresponding 600 nm-reflection are shown.

  20. [Study on the characters of phytoplankton chlorophyll fluorescence excitation spectra based on fourth-derivative].

    PubMed

    Lu, Lu; Su, Rong-Guo; Wang, Xiu-Lin; Zhu, Chen-Jian

    2007-11-01

    Chlorophyll fluorescence excitation spectra of six phytoplankton species, belonging to Bacillariophyta and Dinophyta, were dealt by fourth-derivative analysis with the Matlab program. The results show that between 350 nm and 550 nm six fluorescence peaks were found in the fourth-derivative spectra, which are representatives of non-pigments, chlorophylls and carotenoides respectively. The method makes Bacillariophyta and Dinophyta more distinguishable when the fourth-derivative spectra are compared with the chlorophyll fluorescence excitation spectra. It can be used not only to discriminate the two groups of algaes, but also to reduce the effect of noise. The fluorescence peaks in the fourth-derivative spectra are proved to be stable.

  1. 32nm overlay improvement capabilities

    NASA Astrophysics Data System (ADS)

    Eichelberger, Brad; Huang, Kevin; O'Brien, Kelly; Tien, David; Tsai, Frank; Minvielle, Anna; Singh, Lovejeet; Schefske, Jeffrey

    2008-03-01

    The industry is facing a major challenge looking forward on the technology roadmap with respect to overlay control. Immersion lithography has established itself as the POR for 45nm and for the next few nodes. As the gap closes between scanner capability and device requirements new methodologies need to be taken into consideration. Double patterning lithography is an approach that's being considered for 32 and below, but it creates very strict demands for overlay performance. The fact that a single layer device will need to be patterned using two sequential single processes creates a strong coupling between the 1st and 2nd exposure. The coupling effect during the double patterning process results in extremely tight tolerances for overlay error and scanner capabilities. The purpose of this paper is to explore a new modeling method to improve lithography performance for the 32nm node. Not necessarily unique for double patterning, but as a general approach to improve overlay performance regardless of which patterning process is implemented. We will achieve this by performing an in depth source of variance analysis of current scanner performance and project the anticipated improvements from our new modeling approach. Since the new modeling approach will involve 2nd and 3rd order corrections we will also provide and analysis that outlines current metrology capabilities and sampling optimizations to further expand the opportunities of an efficient implementation of such approach.

  2. Sediment mineralogy based on visible and near-infrared reflectance spectroscopy

    USGS Publications Warehouse

    Jarrard, R.D.; Vanden Berg, M.D.; ,

    2006-01-01

    Visible and near-infrared spectroscopy (VNIS) can be used to measure reflectance spectra (wavelength 350-2500 nm) for sediment cores and samples. A local ground-truth calibration of spectral features to mineral percentages is calculated by measuring reflectance spectra for a suite of samples of known mineralogy. This approach has been tested on powders, core plugs and split cores, and we conclude that it works well on all three, unless pore water is present. Initial VNIS studies have concentrated on determination of relative proportions of carbonate, opal, smectite and illite in equatorial Pacific sediments. Shipboard VNIS-based determination of these four components was demonstrated on Ocean Drilling Program Leg 199. ?? The Geological Society of London 2006.

  3. Reference solar spectra: how do they compare in the UV?

    NASA Astrophysics Data System (ADS)

    Gueymard, C.

    Reference spectra covering all (or nearly all) the solar spectrum and integrating to at least 95% of the solar constant are needed in a variety of disciplines. Due to current experimental limitations these spectra are not monolithic but are rather composites that need to be assembled from a mix of space measurements, ground observatory measurements, and solar models. Depending on the sources of data used in each waveband and various scaling factors, these reference spectra may differ substantially. The focus is here on those historic spectra that have reached standard or pseudo-standard status [ASTM, Colina, Kurucz, Smith & Gottlieb, Thekaekara, and Wehrli]. The UV part of each of these spectra are compared to that of a recently published reference spectrum (Gueymard, 2004), to a UV spectrum measured at the Mauna Loa Observatory with a Brewer spectrophotometer (Gröbner and Kerr, 2001), and to the latest measured data from the SORCE satellite with the SIM and SOLSTICE instruments. In particular, it is found that the Gueymard and Gröbner spectra are in almost perfect agreement over the whole spectral range of the latter (295--355 nm), at their common resolution of 0.5 nm. In comparison, the older Wehrli spectrum shows noticeable differences. The relationship between the experimental wavelength accuracy and the absolute accuracy of these spectra is discussed in detail. In the UV, it is argued that wavelength accuracy is the dominant source of error in the most recent spectra, although absolute calibration generally becomes the dominant factor when considering relaxed resolutions (e.g., > 5 nm). The process of deriving reference spectra is now being standardized by ISO (Tobiska and Nusinov, 2000; ISO, 2002). This initiative opens the door to the development of more dependable and intercomparable spectra. In particular, the derivation of the recent Gueymard spectrum and how it respects the ISO guidelines are discussed in detail.

  4. Atomic Spectra Database (ASD)

    National Institute of Standards and Technology Data Gateway

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

  5. Experimental research of fluorescence spectra of watercress stressed by lack or excess of watering

    NASA Astrophysics Data System (ADS)

    Bullo, O. A.; Fedotov, Yu. V.; Belov, M. L.; Gorodnichev, V. A.

    2015-11-01

    Experimental laboratory investigations of the laser-induced fluorescence spectra of watercress were conducted. The fluorescence spectra were excited by a YAG:Nd laser emitting at 532 nm. The laboratory setup was described and fluorescence spectra of watercress in stressed states caused by lack and excess of water were presented. It was established that the influence of stress caused by lack and excess of watering is manifested in changes of fluorescence spectra.

  6. Optical absorption spectra of pairs of small metal particles

    NASA Astrophysics Data System (ADS)

    Quinten, M.; Kreibig, U.; Schönauer, D.; Genzel, L.

    1985-06-01

    The influence of plasma resonance coupling in small Au particle pairs on their optical properties was calculated including retardation effects. The latter prove to be important for sizes above 15 nm. For pairs of smaller particles a Maxwell-Garnett formula is derived and absorption spectra are calculated explicitly. Comparison with optical absorption spectra measured on aggregated Au particle hydrosols, gives good agreement concerning the splitting up of the dipolar single-particle plasma resonance band.

  7. Fourier transform Raman and IR spectra of snake skin

    NASA Astrophysics Data System (ADS)

    Barry, B. W.; Williams, A. C.; Edwards, H. G. M.

    1993-06-01

    The Fourier transform (FT) Raman and IR spectra of the shed dorsal skin of the snake Elaphe obsoleta (American black rat snake) are reported. Vibrational spectroscopic assignments are proposed for the first time. Although good quality Raman spectra were obtained from the hinge regions using an FT Raman microscope, the dorsal scale regions fluoresced even with 1064 nm IR excitation. This was ascribed to pigmentation markings on the scales.

  8. EUV Emission Spectra and Gain in Polyacetal Capillary Discharge

    NASA Astrophysics Data System (ADS)

    Vrbova, M.; Vrba, P.; Jancarek, A.; Bobrova, N. A.; Sasorov, P. V.; Limpouch, J.; Pina, L.; Nadvornikova, L.; Fojtik, A.

    2002-11-01

    Experimental and computer studies of polyacetal capillary discharge are reported. Time resolved spectra in the wavelength region 3 - 25 nm are measured. Space-time dependences of plasma electron density and temperature are calculated by means of MHD code. Time profiles of selected lithium-, helium- and hydrogen-like carbon and oxygen ion populations and time resolved spectra are evaluated by means of the FLY code. Gain factors for a capillary initially either evacuated or filled by polyacetal vapors are calculated.

  9. Photoacoustic spectra of malachite green adsorbed on silica gel surface

    NASA Astrophysics Data System (ADS)

    Sikorska, Anna; Zachara, Stanislaw

    1992-11-01

    Photoacoustic spectra of malachite green adsorbed on silica gel were investigated at high dye concentrations. The measurements were carried out for two markedly differing layer thicknesses of dyed silica. The ratio of maxima of two characteristic dye bands at (lambda) equals 620 nm and (lambda) equals 425 nm was chosen as an indicator of concentration dependent changes in the shapes of the photoacoustic spectra investigated. The comparison of experimental data with the theoretical model implies that the changes observed in the shape of the spectrum result first of all from the mechanism of the signal generation in inhomogeneous medium.

  10. Analysis of Cervical Supernatant Samples Luminescence Using 355 nm Laser

    NASA Astrophysics Data System (ADS)

    Vaitkuviene, A.; Gegzna, V.; Kurtinaitiene, R.; Stanikunas, R.; Rimiene, J.; Vaitkus, J.

    2010-05-01

    The biomarker discovery for accurate detection and diagnosis of cervical carcinoma and its malignant precursors represents one of the current challenges in clinical medicine. Laser induced autofluorescence spectra in cervical smear content were fitted to predict the cervical epithelium diagnosis as a lab off "optical biopsy" method. Liquid PAP supernatant sediment dried on Quartz plate spectroscopy was performed by 355 nm Nd YAG microlaser STA-1 (Standa, Ltd). For comparison a liquid supernatant spectroscopy was formed by laboratory "Perkin Elmer LS 50B spetrometer at 290, 300, 310 nm excitations. Analysis of spectrum was performed by approximation using the multi-peaks program with Lorentz functions for the liquid samples and with Gaussian functions for the dry samples. Ratio of spectral components area to the area under whole experimental curve (SPP) was calculated. The spectral components were compared by averages of SPP using Mann-Whitney U-test in histology groups. Results. Differentiation of Normal and HSIL/CIN2+ cases in whole supernatant could be performed by stationary laboratory lamp spectroscopy at excitation 290 nm and emission >379 nm with accuracy AUC 0,69, Sens 0,72, Spec 0,65. Differentiation Normal versus HSIL/CIN2+ groups in dried enriched supernatant could be performed by 355 nm microlaser excitation at emission 405-424 nm with accuracy (AUC 0,96, Sens 0,91, Spec 1.00). Diagnostic algorithm could be created for all histology groups differentiation under 355 nm excitation. Microlaser induced "optical biopsy "looks promising method for cervical screening at the point of care.

  11. Circular Dichroism Spectra of Granal and Agranal Chloroplasts of Maize

    PubMed Central

    Faludi-Dániel, Ágnes; Demeter, S.; Garay, A. S.

    1973-01-01

    Granum-containing chloroplasts from mesophyll cells of maize (Zea mays L. var. MV 861) leaves exhibited circular dichroism spectra with a large double signal; peaks at 696 nm (+) and 680 nm (−). In the circular dichroism spectra obtained with agranal chloroplasts of bundle sheath cells, this large double signal is absent. Separation of grana lamellae, in a medium of low salt concentration and in KSCN solution, resulted only in a slight decrease of the amplitude, while upon treatment with digitonin the large double signal disappeared. A negative signal of the chlorophyll b peak at 654 nm was observed in the case of both granal and agranal chloroplasts, and it was not affected either by low salt or by digitonin treatment. A positive peak at about 515 nm was higher in granal than in agranal chloroplasts. PMID:16658498

  12. Parmeterization of spectra

    NASA Technical Reports Server (NTRS)

    Cornish, C. R.

    1983-01-01

    Following reception and analog to digital conversion (A/D) conversion, atmospheric radar backscatter echoes need to be processed so as to obtain desired information about atmospheric processes and to eliminate or minimize contaminating contributions from other sources. Various signal processing techniques have been implemented at mesosphere-stratosphere-troposphere (MST) radar facilities to estimate parameters of interest from received spectra. Such estimation techniques need to be both accurate and sufficiently efficient to be within the capabilities of the particular data-processing system. The various techniques used to parameterize the spectra of received signals are reviewed herein. Noise estimation, electromagnetic interference, data smoothing, correlation, and the Doppler effect are among the specific points addressed.

  13. Rock Outcrop Spectra

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The color image on the lower left shows a rock outcrop at Meridiani Planum, Mars. This image was taken by the panoramic camera on the Mars Exploration Rover Opportunity, looking north, and was acquired on the 4th sol, or martian day, of the rover's mission (Jan. 27, 2004). The yellow box outlines an area detailed in the top left image, which is a monochrome (single filter) image from the rover's panoramic camera. The top image uses solid colors to show several regions on or near the rock outcrop from which spectra were extracted: the dark soil above the outcrop (yellow), the distant horizon surface (aqua), a bright rock in the outcrop (green), a darker rock in the outcrop (red), and a small dark cobblestone (blue). Spectra from these regions are shown in the plot to the right.

  14. Title: Near-UV behaviour of observed TNO reflectance spectra

    NASA Astrophysics Data System (ADS)

    Seccull, Tom; Fraser, Wesley Cristopher; Izawa, Matthew; Brown, Michael E.

    2016-10-01

    Observed spectra provide the best diagnostics of the surface compositions of Trans-Neptunian Objects (TNOs). We have observed the spectra of 7 TNOs, from across almost the full range of dynamical classes, using the VLT's X-Shooter spectrograph. Compared to the 5 targets in our sample which exhibit linear spectra in the UV-optical range, two of of our targets show highly unusual spectral behaviour, whereby their reflectance decreases sharply at wavelengths below ~440nm. Those same objects exhibit typically unremarkable spectra in the optical and near-IR spectral regions. In these regions where available, our observed spectra of the targets are in agreement with spectra or photometry available in the literature. Using a different solar analogue to produce our reflectance spectra does not remove the UV decrease exhibited by the two targets. Further, it appears that neither reducing the spectra with different pipelines, nor using drastically different parameters in those pipelines changes this general behaviour. Based on laboratory spectra of complex hydrocarbons it is plausible that the near-UV behaviour is the result of a surface coating of organic substances on the TNOs which exhibit it. The spectra of organics are also consistent in having a general red slope similar to that observed in the spectra of many TNOs. While laboratory spectra of some silicate substances also show a decrease in reflectance in the near-UV spectral region that is in principle consistent with our observations, those silicates do not exhibit a red slope consistent with our optical spectra. Hence, the hypothesis that silicates are present seems less likely than the hypothesis that this UV decrease is due to the presence of organics on the surfaces of these objects.

  15. Barnacle Bill Spectra

    NASA Technical Reports Server (NTRS)

    1997-01-01

    These IMP spectra show the characteristics of the rock surface measured by the Alpha Proton X-Ray Spectrometer (blue), the soil trapped in pits on the rock surface (red), and the deposit of bright drift on the top of the rock. The area measured by the APXS has the properties expected for nearly unweathered igneous rock, and the soil trapped in the pits is intermediate to the unweathered rock and the highly weathered drift material.

  16. SPECTRAFACTORY.NET: A DATABASE OF MOLECULAR MODEL SPECTRA

    SciTech Connect

    Cami, J.; Van Malderen, R.; Markwick, A. J. E-mail: Andrew.Markwick@manchester.ac.uk

    2010-04-01

    We present a homogeneous database of synthetic molecular absorption and emission spectra from the optical to mm wavelengths for a large range of temperatures and column densities relevant for various astrophysical purposes, but in particular for the analysis, identification, and first-order analysis of molecular bands in spectroscopic observations. All spectra are calculated in the LTE limit from several molecular line lists, and are presented at various spectral resolving powers corresponding to several specific instrument simulations. The database is available online at http://www.spectrafactory.net, where users can freely browse, search, display, and download the spectra. We describe how additional model spectra can be requested for (automatic) calculation and inclusion. The database already contains over half a million model spectra for 39 molecules (96 different isotopologues) over the wavelength range 350 nm-3 mm ({approx}3-30000 cm{sup -1})

  17. VizieR Online Data Catalog: Classification of stellar spectra 644-681nm (Damiani+, 2014)

    NASA Astrophysics Data System (ADS)

    Damiani, F.; Prisinzano, L.; Micela; G.; Randich, S.; Gilmore, G.; Drew, J. E.; Jeffries, R. D.; Fremat, Y.; Alfaro, E. J.; Bensby, T.; Bragaglia, A.; Flaccomio, E.; Lanzafame, A. C.; Pancino, E.; Recio-Blanco, A.; Sacco, G. G.; Smiljanic, R.; Jackson, R. J.; de Laverny, P.; Morbidelli, L.; Worley, C. C.; Hourihane, A.; Costado, M. T.; Jofre, P.; Lind, K.; Maiorca, E.

    2014-05-01

    A set of newly-defined spectral indices is presented for all stars in the field of the γ Vel cluster, observed within the Gaia-ESO Survey. All indices are based exclusively on the spectral range 6440-6810 Angstroms, corresponding to the VLT/FLAMES Giraffe setup HR15N. Fundamental stellar parameters can be derived from these indices as explained in the paper. Stars with either high cluster membership probability, or/and SB2 binaries, are flagged. (2 data files).

  18. Spectroscopy of Pluto at six longitudes, 380-930 nm

    NASA Astrophysics Data System (ADS)

    Cruikshank, Dale P.; Pinilla-Alonso, Noemi; Lorenzi, Vania; Grundy, Will M.; Licandro, Javier; Binzel, Richard P.

    2014-11-01

    We have obtained spectra of the Pluto-Charon pair (unresolved) in the wavelength range 380-930 nm with resolution ~450 at six roughly equally spaced longitudes. The data were taken in May and June, 2014, with the 4.2-m Isaac Newton Telescope at Roque de Los Muchachos Observatory in the Canary Islands, using the ACAM (auxiliary-port camera) in spectrometer mode, and using two solar analog stars. The new spectra clearly show absorption bands of solid CH4 at 620, 728, and 850-910 nm, which were known from earlier work. The 620-nm CH4 band is intrinsically very weak, and its appearance indicates a long optical pathlength through the ice. This is especially true if it arises from CH4 dissolved in N2 ice. Earlier work (Owen et al. Science 261, 745, 1993) on the near-infrared spectrum of Pluto (1-2.5 µm) has shown that the CH4 bands are shifted to shorter wavelengths because the CH4 occurs as a solute in beta-phase crystalline N2. The optical pathlength through the N2 crystals must be on the order of several cm to produce the N2 band observed at 2.15 µm. The new spectra exhibit a pronounced red slope across the entire wavelength range; the slope is variable with longitude, and differs in a small but significant way from that measured at comparable longitudes by Grundy & Fink (Icarus 124, 329, 1996) in their 15-year study of Pluto’s spectrum (500-1000 nm). The new spectra will provide an independent means for calibrating the color filter bands on the Multispectral Visible Imaging Camera (MVIC) (Reuter et al. Space Sci. Rev. 140, 129, 2008) on the New Horizons spacecraft, which will encounter the Pluto-Charon system in mid-2015. They will also form the basis of modeling the spectrum of Pluto at different longitudes to help establish the nature of the non-ice component(s) of Pluto’s surface. It is presumed that the non-ice component is the source of the yellow-red coloration of Pluto, which is known to be variable across the surface.

  19. Spectroscopy of Pluto, 380-930 Nm at Six Longitudes

    NASA Technical Reports Server (NTRS)

    Cruikshank, D. P.; Pinilla-Alonso, N.; Lorenzi, V.; Grundy, William; Licandro, J.; Binzel, R. P.

    2014-01-01

    We have obtained spectra of the Pluto-Charon pair (unresolved) in the wavelength range 380-930 nm with resolution approx..450 at six roughly equally spaced longitudes. The data were taken in May and June, 2014, with the 4.2-m Isaac Newton Telescope at Roque de Los Muchachos Observatory in the Canary Islands, using the ACAM (auxiliary-port camera) in spectrometer mode, and using two solar analog stars. The new spectra clearly show absorption bands of solid CH4 at 620, 728, and 850-910 nm, which were known from earlier work. The 620-nm CH4 band is intrinsically very weak, and its appearance indicates a long optical path-length through the ice. This is especially true if it arises from CH4 dissolved in N2 ice. Earlier work (Owen et al. Science 261, 745, 1993) on the near-infrared spectrum of Pluto (1-2.5 microns) has shown that the CH4 bands are shifted to shorter wavelengths because the CH4 occurs as a solute in beta-phase crystalline N2. The optical path-length through the N2 crystals must be on the order of several cm to produce the N2 band observed at 2.15 microns. The new spectra exhibit a pronounced red slope across the entire wavelength range; the slope is variable with longitude, and differs in a small but significant way from that measured at comparable longitudes by Grundy & Fink (Icarus 124, 329, 1996) in their 15-year study of Pluto's spectrum (500-1000 nm). The new spectra will provide an independent means for calibrating the color filter bands on the Multispectral Visible Imaging Camera (MVIC) (Reuter et al. Space Sci. Rev. 140, 129, 2008) on the New Horizons spacecraft, which will encounter the Pluto-Charon system in mid-2015. They will also form the basis of modeling the spectrum of Pluto at different longitudes to help establish the nature of the non-ice component(s) of Pluto's surface. It is presumed that the non-ice component is the source of the yellow-red coloration of Pluto, which is known to be variable across the surface.

  20. Measurements of the Ultraviolet Fluorescence Cross Sections and Spectra of Bacillus Anthracis Simulants

    SciTech Connect

    Stephens, J.R.

    1998-09-01

    Measurements of the ultraviolet autofluorescence spectra and absolute cross sections of the Bacillus anthracis (Ba) simulants Bacillus globigii (Bg), Bacillus megaterium (Bm), Bacillus subtilis (Bs), and Bacillus cereus (Bc) were measured. Fluorescence spectra and cross sections of pine pollen (Pina echinata) were measured for comparison. Both dried vegetative cells and spores separated from the sporulated vegetative material were studied. The spectra were obtained by suspending a small number (<10) of particles in air in our Single Particle Spectroscopy Apparatus (SPSA), illuminating the particles with light from a spectrally filtered arc lamp, and measuring the fluorescence spectra of the particles. The illumination was 280 nm (20 nm FWHM) and the fluorescence spectra was measured between 300 and 450 nm. The fluorescence cross section of vegetative Bg peaks at 320 nm with a maximum cross section of 5 X 10{sup -14} cm{sup 2}/sr-nm-particle while the Bg spore fluorescence peaks at 310 nm with peak fluorescence of 8 X 10{sup -15} cm{sup 2}/sr-nm-particle. Pine pollen particles showed a higher fluorescence peaking at 355 nm with a cross section of 1.7 X 10{sup -13} cm{sup 2}/sr-nm-particle. Integrated cross sections ranged from 3.0 X 10{sup -13} for the Bg spores through 2.25 X 10{sup -12} (cm{sup 2}/sr-particle) for the vegetative cells.

  1. Creating semiconductor metafilms with designer absorption spectra.

    PubMed

    Kim, Soo Jin; Fan, Pengyu; Kang, Ju-Hyung; Brongersma, Mark L

    2015-01-01

    The optical properties of semiconductors are typically considered intrinsic and fixed. Here we leverage the rapid developments in the field of optical metamaterials to create ultrathin semiconductor metafilms with designer absorption spectra. We show how such metafilms can be constructed by placing one or more types of high-index semiconductor antennas into a dense array with subwavelength spacings. It is argued that the large absorption cross-section of semiconductor antennas and their weak near-field coupling open a unique opportunity to create strongly absorbing metafilms whose spectral absorption properties directly reflect those of the individual antennas. Using experiments and simulations, we demonstrate that near-unity absorption at one or more target wavelengths of interest can be achieved in a sub-50-nm-thick metafilm using judiciously sized and spaced Ge nanobeams. The ability to create semiconductor metafilms with custom absorption spectra opens up new design strategies for planar optoelectronic devices and solar cells. PMID:26184335

  2. Creating semiconductor metafilms with designer absorption spectra

    PubMed Central

    Kim, Soo Jin; Fan, Pengyu; Kang, Ju-Hyung; Brongersma, Mark L.

    2015-01-01

    The optical properties of semiconductors are typically considered intrinsic and fixed. Here we leverage the rapid developments in the field of optical metamaterials to create ultrathin semiconductor metafilms with designer absorption spectra. We show how such metafilms can be constructed by placing one or more types of high-index semiconductor antennas into a dense array with subwavelength spacings. It is argued that the large absorption cross-section of semiconductor antennas and their weak near-field coupling open a unique opportunity to create strongly absorbing metafilms whose spectral absorption properties directly reflect those of the individual antennas. Using experiments and simulations, we demonstrate that near-unity absorption at one or more target wavelengths of interest can be achieved in a sub-50-nm-thick metafilm using judiciously sized and spaced Ge nanobeams. The ability to create semiconductor metafilms with custom absorption spectra opens up new design strategies for planar optoelectronic devices and solar cells. PMID:26184335

  3. Creating semiconductor metafilms with designer absorption spectra

    NASA Astrophysics Data System (ADS)

    Kim, Soo Jin; Fan, Pengyu; Kang, Ju-Hyung; Brongersma, Mark L.

    2015-07-01

    The optical properties of semiconductors are typically considered intrinsic and fixed. Here we leverage the rapid developments in the field of optical metamaterials to create ultrathin semiconductor metafilms with designer absorption spectra. We show how such metafilms can be constructed by placing one or more types of high-index semiconductor antennas into a dense array with subwavelength spacings. It is argued that the large absorption cross-section of semiconductor antennas and their weak near-field coupling open a unique opportunity to create strongly absorbing metafilms whose spectral absorption properties directly reflect those of the individual antennas. Using experiments and simulations, we demonstrate that near-unity absorption at one or more target wavelengths of interest can be achieved in a sub-50-nm-thick metafilm using judiciously sized and spaced Ge nanobeams. The ability to create semiconductor metafilms with custom absorption spectra opens up new design strategies for planar optoelectronic devices and solar cells.

  4. UV-IR Spectra of the Icy Saturnian Satellites

    NASA Astrophysics Data System (ADS)

    Hendrix, A. R.; Filacchione, G.; Schenk, P.; Clark, R. N.; Cuzzi, J. N.; Noll, K. S.; Spencer, J. R.

    2014-12-01

    Cassini's multi-instrument suite allows simultaneous observations of the icy satellites of Saturn over a wide range of wavelengths. We present composite UV-IR spectra (0.1-5 microns) of the leading and trailing hemispheres of the icy moons using data from Cassini supplemented with spectra from Hubble Space Telescope (STIS). We use data of Mimas, Enceladus, Tethys, Dione and Rhea from the Ultraviolet Imaging Spectrograph (UVIS), the Imaging Subsystem (ISS) and the Visual-Near Infrared Mapping Spectrometer (VIMS) taken during simultaneous measurements, or using similar observational geometries. The well-studied phase curve behaviors of the satellites are utilized to readily combine Earth-based STIS data with the Cassini datasets to create composite spectra. Focusing primarily on the UV-visible region so far, we find that the spectra of all satellites are bright and spectrally relatively flat at visible wavelengths longer than 500-600 nm; shortward of 500-600 nm the surfaces become absorbing with wavelength, resulting in reddish spectra. The satellites exhibit flattish-to-bowl-shaped spectra in the ~200-350 nm range and demonstrate the 165 nm water ice absorption edge, in varying strengths. These composite spectra are used to study the system-wide surface compositions of the satellites to understand large-scale exogenic effects (e.g., E-ring grain bombardment and radiolytic processing) at a variety of regolith sensing depths, and in particular to study implications for the presence and distribution of organics, ammonia, and other non-H2O-ice species in the system.

  5. Observation of Quiet Limb in He I 1083.0 nm, H Paschen alpha1281.8 nm and H Brackett gamma 2166.1 nm lines

    NASA Astrophysics Data System (ADS)

    Prasad Choudhary, Debi

    2016-05-01

    In this paper, we shall present the results of an observational study of the quiet solar limb in the near infrared lines using the New IR Array Camera (NAC) and the vertical spectrograph at the focal plane of McMath-Pierce telescope. The NAC, at the exit port of the spectrograph, was used to record the limb spectrum in HeI 1083.0 nm, Hydrogen Paschen 1281.8 nm and Brackett 2165.5 nm wavelength regions. The NAC is a 1024x1024 InSb Alladin III Detector operating over 1-5 micron range with high density sampling at 0.018 arc second/pixel. The all-reflective optical train minimizes number of surfaces and eliminates ghosts leading to low scatter, ghost-free optics. The close-cycle cryogenic provides a stable cooling environment over six hour period with an accuracy of 0.01K leading to low dark current. The low read out noise combined with low scattered light and dark current makes NAC an ideal detector for making high quality infrared spectral observations of solar limb. The limb spectrums were obtained by placing the spectrograph slit perpendicular to the limb at an interval of 10 degrees around the solar disk. We shall report the intensity profile, line-of-sight velocity and line width distribution around the sun derived from the spectra along the slit.

  6. Spectra of particulate backscattering in natural waters.

    PubMed

    Gordon, Howard R; Lewis, Marlon R; McLean, Scott D; Twardowski, Michael S; Freeman, Scott A; Voss, Kenneth J; Boynton, G Chris

    2009-08-31

    Hyperspectral profiles of downwelling irradiance and upwelling radiance in natural waters (oligotrophic and mesotrophic) are combined with inverse radiative transfer to obtain high resolution spectra of the absorption coefficient (a) and the backscattering coefficient (b(b)) of the water and its constituents. The absorption coefficient at the mesotrophic station clearly shows spectral absorption features attributable to several phytoplankton pigments (Chlorophyll a, b, c, and Carotenoids). The backscattering shows only weak spectral features and can be well represented by a power-law variation with wavelength (lambda): b(b) approximately lambda(-n), where n is a constant between 0.4 and 1.0. However, the weak spectral features in b(b)b suggest that it is depressed in spectral regions of strong particle absorption. The applicability of the present inverse radiative transfer algorithm, which omits the influence of Raman scattering, is limited to lambda < 490 nm in oligotrophic waters and lambda < 575 nm in mesotrophic waters. PMID:19724619

  7. Spectra of Particulate Backscattering in Natural Waters

    NASA Technical Reports Server (NTRS)

    Gordon, Howard, R.; Lewis, Marlon R.; McLean, Scott D.; Twardowski, Michael S.; Freeman, Scott A.; Voss, Kenneth J.; Boynton, Chris G.

    2009-01-01

    Hyperspectral profiles of downwelling irradiance and upwelling radiance in natural waters (oligotrophic and mesotrophic) are combined with inverse radiative transfer to obtain high resolution spectra of the absorption coefficient (a) and the backscattering coefficient (bb) of the water and its constituents. The absorption coefficient at the mesotrophic station clearly shows spectral absorption features attributable to several phytoplankton pigments (Chlorophyll a, b, c, and Carotenoids). The backscattering shows only weak spectral features and can be well represented by a power-law variation with wavelength (lambda): b(sub b) approx. Lambda(sup -n), where n is a constant between 0.4 and 1.0. However, the weak spectral features in b(sub b), suggest that it is depressed in spectral regions of strong particle absorption. The applicability of the present inverse radiative transfer algorithm, which omits the influence of Raman scattering, is limited to lambda < 490 nm in oligotrophic waters and lambda < 575 nm in mesotrophic waters.

  8. Comprehensive Analyses of the Spectra of Iron-group Elements

    NASA Astrophysics Data System (ADS)

    Nave, Gillian; Sansonetti, Craig J; Pickering, Juliet C; Liggins, Florence

    2014-06-01

    For many decades, the Atomic Spectroscopy Group at NIST has measured atomic data of vital use to astronomy and other fields using high resolution spectrometers that are found in few other places in the world. These now include the 2-m Fourier transform (FT) spectrometer covering the region 285 nm to 5500 nm, the FT700 vacuum ultraviolet (VUV) FT spectrometer covering the region 143 nm to 900 nm, and a 10.7-m normal incidence spectrograph (NIVS) covering 30 nm to 500 nm. Recent work focused on the measurement and analysis of wavelengths and energy levels of iron-group elements to provide extensive data for the analysis of astrophysical spectra. Our comprehensive linelist for Fe II from 90 nm to 5500 nm contains over 13 600 lines with order of magnitude improvements in the wavelengths compared to previous work [Nave & Johansson, ApJSS 204, 1(2013)]. The spectra were observed in high-current continuous and pulsed hollow cathode (HCL) discharges using FT spectrometers and our NIVS spectrograph. A similar analysis of Cr II contains over 5300 lines and extends the knowledge of this spectrum to the previously unobserved region between 731 nm at 5500 nm [Sansonetti, Nave, Reader & Kerber, ApJSS 202, 15 (2012); Sansonetti & Nave, ApJSS (in prep.)]. Our analysis of the Co III spectrum contains 750 lines observed in Penning discharge lamps and an additional 900 lines compiled from previous work, including Ritz wavelengths, optimized energy levels, and calculated log(gf) values [Smillie, Pickering, Nave & Smith, ApJSS (in prep.)]. NIST and ICL are currently collaborating to complete the measurement and analysis of wavelengths, energy levels, and hyperfine structure parameters for all singly-ionized iron-group elements of astrophysical interest, covering the wavelength range 80 nm to 5500 nm. This project uses archival data from FT spectrometers at NIST, ICL and Kitt Peak National Observatory, with additional spectra of HCL and Penning discharge sources taken using our FT and

  9. Spectral characteristics of caries-related autofluorescence spectra and their use for diagnosis of caries stage

    NASA Astrophysics Data System (ADS)

    Son, Sung-Ae; Jung, Kyeong-Hoon; Ko, Ching-Chang; Kwon, Yong Hoon

    2016-01-01

    The purpose of the present study was to identify factors useful for diagnosis of the caries stage from laser-induced autofluorescence (AF) spectra. Affected teeth were accurately staged and allocated to four groups: sound, stage II, stage III, or stage IV. A 405-nm laser was used to produce AF spectra. The spectrum factors analyzed were spectrum slope at 550 to 600 nm, spectral area from 500 and 590 nm, and intensity ratio of peaks 625 and 667 nm (625/667 nm). DIAGNOdent was used as control measurement. AF spectra of sound teeth had a peak near 500 nm followed by a smooth decline to 800 nm. As caries progressed, some specimens in stages II to IV showed one or two peak(s) near 625 and 667 nm. Slopes at 550 to 600 nm and areas under the curve at 500 to 590 nm were significantly different (p<0.001) for each stage. Two-peak ratios were also significantly different (p<0.001) except for stage III and stage IV. DIAGNOdent readings for sound and stage II and stage III and IV were not significantly different. Among the studied factors, the spectrum slope at 550 to 600 nm and area under curve at 500 to 590 nm could be useful treatment decision-making tools for carious lesions.

  10. Extending the McDonald Observatory Serendipitous Survey of UV/Blue Asteroid Spectra

    NASA Technical Reports Server (NTRS)

    Vilas, Faith; Cochran, A. L.

    1999-01-01

    Moderate resolution asteroid spectra in the 350 - 650 nm spectral range acquired randomly over many years (Cochran and Vilas, Icarus v 127, 121, 1997) identified absorption features in spectra of some of the asteroids. A feature centered at 430 nm was identified in the spectra of some low-albedo asteroids (C class and subclass), similar to the feature identified by Vilas et al. (Icarus, v. 102, 225,1993) in other low-albedo asteroid spectra and attributed to a ferric iron spin-forbidden transition in iron alteration minerals such as jarosite. Features at 505 nm and 430 nm were identified in the spectrum of 4 Vesta. The 505-nm feature is highly diagnostic of the amount and form of calcium in pyroxenes. This suggested further research on the sharpness and spectral placement of this feature in the spectra of Vesta and Vestoids (e.g., Cochran and Vilas, Icarus v. 134, 207, 1998). In 1997 and 1998, additional UV/blue spectra were obtained at the 2.7-m Harlan J. Smith telescope with a facility cassegrain spectrograph. These included spectra of low-albedo asteroids, the R-class asteroid 349 Dembowska, and the M-class asteroid 135 Hertha. These spectra will be presented and identified features will be discussed.

  11. IUE archived spectra

    NASA Technical Reports Server (NTRS)

    Sullivan, Edward C.; Bohlin, Ralph C.; Heap, Sara R.; West, Donald K.; Schmitz, Marion

    1988-01-01

    The International Ultraviolet Explorer (IUE) Satellite has been in continuous operation since January 26, 1978. To date, approximately 65,000 spectra have been stored in an archive at Goddard Space Flight Center in Greenbelt, MD. A number of procedures have been generated to facilitate access to the data in the IUE spectral archive. This document describes the procedures which include on-line quick look of the displays, search of an observation data base for selected observations, and several methods for ordering data from the archive.

  12. Application of normalized spectra in resolving a challenging Orphenadrine and Paracetamol binary mixture.

    PubMed

    Yehia, Ali M; Abd El-Rahman, Mohamed K

    2015-03-01

    Normalized spectra have a great power in resolving spectral overlap of challenging Orphenadrine (ORP) and Paracetamol (PAR) binary mixture, four smart techniques utilizing the normalized spectra were used in this work, namely, amplitude modulation (AM), simultaneous area ratio subtraction (SARS), simultaneous derivative spectrophotometry (S(1)DD) and ratio H-point standard addition method (RHPSAM). In AM, peak amplitude at 221.6nm of the division spectra was measured for both ORP and PAR determination, while in SARS, concentration of ORP was determined using the area under the curve from 215nm to 222nm of the regenerated ORP zero order absorption spectra, in S(1)DD, concentration of ORP was determined using the peak amplitude at 224nm of the first derivative ratio spectra. PAR concentration was determined directly at 288nm in the division spectra obtained during the manipulation steps in the previous three methods. The last RHPSAM is a dual wavelength method in which two calibrations were plotted at 216nm and 226nm. RH point is the intersection of the two calibration lines, where ORP and PAR concentrations were directly determined from coordinates of RH point. The proposed methods were applied successfully for the determination of ORP and PAR in their dosage form.

  13. Application of normalized spectra in resolving a challenging Orphenadrine and Paracetamol binary mixture

    NASA Astrophysics Data System (ADS)

    Yehia, Ali M.; Abd El-Rahman, Mohamed K.

    2015-03-01

    Normalized spectra have a great power in resolving spectral overlap of challenging Orphenadrine (ORP) and Paracetamol (PAR) binary mixture, four smart techniques utilizing the normalized spectra were used in this work, namely, amplitude modulation (AM), simultaneous area ratio subtraction (SARS), simultaneous derivative spectrophotometry (S1DD) and ratio H-point standard addition method (RHPSAM). In AM, peak amplitude at 221.6 nm of the division spectra was measured for both ORP and PAR determination, while in SARS, concentration of ORP was determined using the area under the curve from 215 nm to 222 nm of the regenerated ORP zero order absorption spectra, in S1DD, concentration of ORP was determined using the peak amplitude at 224 nm of the first derivative ratio spectra. PAR concentration was determined directly at 288 nm in the division spectra obtained during the manipulation steps in the previous three methods. The last RHPSAM is a dual wavelength method in which two calibrations were plotted at 216 nm and 226 nm. RH point is the intersection of the two calibration lines, where ORP and PAR concentrations were directly determined from coordinates of RH point. The proposed methods were applied successfully for the determination of ORP and PAR in their dosage form.

  14. [Spectra analysis of ignition flame in two-stroke gasoline engine burning blended fuel].

    PubMed

    Sheng, K; Ning, W; Zhang, G; Cheng, X; Wang, Z

    1998-12-01

    In a two-stroke gasoline engine, exhaust gas pollution is especially severe when it burns rich mixture of blended fuel. The results of spectra analysis of ignition combustion flame show that the peak luminous intensities of three characteristic spectra CH(431.5nm), C2(516.5nm) and CN(387nm) are strong, of which the peak luminous intensity of CN(387nm) is the most outstanding. The mechanism of NO(x) formation in exhaust gas can be illustrated by Fenimore theorem. The mechanism was also verified by experiments conducted by Japanese researcher K. Nagase.

  15. Generation of Thermospheric OI 845 nm Emission by Bowen Fluorescence

    NASA Astrophysics Data System (ADS)

    Huestis, D. L.; Sharpee, B. D.; Cosby, P. C.; Slanger, T. G.

    2006-12-01

    777 and 845 nm emissions from the 3p-3s multiplets of atomic oxygen are commonly observed at non-auroral latitudes in the terrestrial nightglow. By studying the relative strengths of these emissions we can learn something about the mechanisms that produce them and what they can teach us about the atmosphere. Recently [1] we have used intensity-calibrated sky spectra from the Keck telescopes to investigate the relative strengths of a wide range of O-atom Rydberg lines and have confirmed that electron-ion radiative recombination is a primary source of excitation for both the triplet and quintet systems. Following the intensity of the 777 and 845 nm lines during the night, we find that for most of the night the quintet 777 nm line is consistently stronger than the triplet 845 nm line, with a nearly constant intensity ratio I(777)/I(845) near 2.3, although both intensities fall rapidly as the night progresses. However, late in the night the 845 nm intensity levels off, while the 777 nm intensity continues to fall, and the I(777)/I(845) ratio plunges by a factor of 5-10. We interpret these observations as indicating that the O-atom quintet states are still being excited by the same mechanism as earlier in the night, i.e. radiative recombination, but some triplet states are also being excited by an additional mechanism. Such a mechanism has been proposed before [2-6] but not previously observed directly in the terrestrial nightglow. The oxygen triplet 3d-2p transition at 102.576 nm is in close coincidence with the solar hydrogen Lyman-β line at 102.572 nm. Radiative transport in the hydrogen geocorona will deliver Lyman-β intensity into the Earth's shadow and will produce triplet O(3d 3D) high in the atmosphere, even prior to direct solar illumination. The result is observable in a radiative cascade sequence 3d-3p(1129 nm) → 3p- 3s(845 nm) → 3s-2p(130 nm). A similar effect is observed in the H-α emission, which is also excited by Lyman-β absorption. This process

  16. Meteors and meteorites spectra

    NASA Astrophysics Data System (ADS)

    Koukal, J.; Srba, J.; Gorková, S.; Lenža, L.; Ferus, M.; Civiš, S.; Knížek, A.; Kubelík, P.; Kaiserová, T.; Váňa, P.

    2016-01-01

    The main goal of our meteor spectroscopy project is to better understand the physical and chemical properties of meteoroids. Astrometric and spectral observations of real meteors are obtained via spectroscopic CCD video systems. Processed meteor data are inserted to the EDMOND database (European viDeo MeteOr Network Database) together with spectral information. The fully analyzed atmospheric trajectory, orbit and also spectra of a Leonid meteor/meteoroid captured in November 2015 are presented as an example. At the same time, our target is the systematization of spectroscopic emission lines for the comparative analysis of meteor spectra. Meteoroid plasma was simulated in a laboratory by laser ablation of meteorites samples using an (ArF) excimer laser and the LIDB (Laser Induced Dielectric Breakdown) in a low pressure atmosphere and various gases. The induced plasma emissions were simultaneously observed with the Echelle Spectrograph and the same CCD video spectral camera as used for real meteor registration. Measurements and analysis results for few selected meteorite samples are presented and discussed.

  17. Raman spectra of carotenoids in natural products.

    PubMed

    Withnall, Robert; Chowdhry, Babur Z; Silver, Jack; Edwards, Howell G M; de Oliveira, Luiz F C

    2003-08-01

    Resonance Raman spectra of naturally occurring carotenoids have been obtained from nautilus, periwinkle (Littorina littorea) and clam shells under 514.5 nm excitation and these spectra are compared with the resonance Raman spectra obtained in situ from tomatoes, carrots, red peppers and saffron. The tomatoes, carrots and red peppers gave rise to resonance Raman spectra exhibiting a nu1 band at ca. 1520 cm(-1), in keeping with its assignment to carotenoids with ca. nine conjugated carbon-carbon double bonds in their main chains, whereas the resonance Raman spectrum of saffron showed a nu1 band at 1537 cm(-1) which can be assigned to crocetin, having seven conjugated carbon-carbon double bonds. A correlation between nu1 wavenumber location and effective conjugated chain length has been used to interpret the data obtained from the shells, and the wavenumber position (1522 cm(-1)) of the nu1 band of the carotenoid in the orange clam shell suggests that it contains nine conjugated double bonds in the main chain. However, the black periwinkle and nautilus shells exhibit nu1 bands at 1504 and 1496 cm(-1), respectively. On the basis of the correlation between nu1 wavenumber location and effective conjugated chain length, this indicates that they contain carotenoids with longer conjugated chains, the former having ca. 11 double bonds and the latter ca. 13 or even more. Raman spectra of the nautilus, periwinkle and clam shells also exhibited a strong band at 1085 cm(-1) and a doublet with components at 701 and 705 cm(-1), which can be assigned to biogenic calcium carbonate in the aragonite crystallographic form. PMID:12909134

  18. Raman spectra of carotenoids in natural products

    NASA Astrophysics Data System (ADS)

    Withnall, Robert; Chowdhry, Babur Z.; Silver, Jack; Edwards, Howell G. M.; de Oliveira, Luiz F. C.

    2003-08-01

    Resonance Raman spectra of naturally occurring carotenoids have been obtained from nautilus, periwinkle ( Littorina littorea) and clam shells under 514.5 nm excitation and these spectra are compared with the resonance Raman spectra obtained in situ from tomatoes, carrots, red peppers and saffron. The tomatoes, carrots and red peppers gave rise to resonance Raman spectra exhibiting a ν1 band at ca. 1520 cm -1, in keeping with its assignment to carotenoids with ca. nine conjugated carboncarbon double bonds in their main chains, whereas the resonance Raman spectrum of saffron showed a ν1 band at 1537 cm -1 which can be assigned to crocetin, having seven conjugated carboncarbon double bonds. A correlation between ν1 wavenumber location and effective conjugated chain length has been used to interpret the data obtained from the shells, and the wavenumber position (1522 cm -1) of the ν1 band of the carotenoid in the orange clam shell suggests that it contains nine conjugated double bonds in the main chain. However, the black periwinkle and nautilus shells exhibit ν1 bands at 1504 and 1496 cm -1, respectively. On the basis of the correlation between ν1 wavenumber location and effective conjugated chain length, this indicates that they contain carotenoids with longer conjugated chains, the former having ca. 11 double bonds and the latter ca. 13 or even more. Raman spectra of the nautilus, periwinkle and clam shells also exhibited a strong band at 1085 cm -1 and a doublet with components at 701 and 705 cm -1, which can be assigned to biogenic calcium carbonate in the aragonite crystallographic form.

  19. Fluorescence spectra of benign and malignant prostate tissues

    NASA Astrophysics Data System (ADS)

    AlSalhi, M. S.; Masilamani, V.; Atif, M.; Farhat, K.; Rabah, D.; Turki, M. R. Al

    2012-09-01

    In this study, fluorescence emission spectrum (FES), Stokes' shift spectrum (SSS), and reflectance spectrum (RS) of benign (N = 12) and malignant prostate tissues (N = 8) were investigated to discriminate the two types of tissues. The FES was done with the excitation at 325 nm only; SSS with Δλ = 70 and Δλ = 0, the latter being equivalent to reflectance spectra. Of the three modes of spectra, SSS with Δλ = 70 nm showed the best discrimination. There were four important bands, one at 280 nm (due to tryptophan); 320 nm (due to elastin & tryptophan); 355 and 385 (due to NADH) and 440 nm (due to flavin). From the relative intensities of these bands, three ratios were evaluated. Similarly another two ratios were obtained from reflectance spectra and one more from FES. Thus, there are 6 ratio parameters which represent the relative concentration of tryptophan, elastin, nicotinamide adenine dinucleotide (NADH), and flavin. A statistical analysis showed that benign and malignant tissues could be classified with accuracy greater than 90%. This report is only for in vitro analysis; but employing optical fiber, this can be extended to in vivo analysis too, so that benign tumor could be distinguished without surgery.

  20. Principal-components analysis of fluorescence cross-section spectra from pathogenic and simulant bacteria

    NASA Astrophysics Data System (ADS)

    Heaton, Harold I.

    2005-10-01

    Principal-components analysis of a new set of highly resolved (<1 nm) fluorescence cross-section spectra excited at 354.7 nm over the 370 646 nm band has been used to demonstrate the potential ability of UV standoff lidars to discriminate among particular biological warfare agents and simulants over short ranges. The remapped spectra produced by this technique from Bacillus globigii (Bg) and Bacillus anthracis (Ba) spores were sufficiently different to allow them to be cleanly separated, and the Ba spectra obtained from Sterne and Ames strain spores were distinguishable. These patterns persisted as the spectral resolution was subsequently degraded in processing from ˜1 to 34 nm. This is to the author's knowledge the first time that resolved fluorescence spectra from biological warfare agents have been speciated or shown to be distinguishably different from those normally used surrogates by optical spectroscopy.

  1. Continuum Fitting HST QSO Spectra

    NASA Technical Reports Server (NTRS)

    Tytler, David; Oliversen, Ronald J. (Technical Monitor)

    2002-01-01

    The Principal Component Analysis (PCA) method which we are using to fit and describe QSO spectra relies upon the fact that QSO continuum are generally very smooth and simple except for emission and absorption lines. To see this we need high signal-to-noise (S/N) spectra of QSOs at low redshift which have relatively few absorption lines in the Lyman-a forest. We need a large number of such spectra to use as the basis set for the PCA analysis which will find the set of principal component spectra which describe the QSO family as a whole. We have found that too few HST spectra have the required S/N and hence we need to supplement them with ground based spectra of QSOs at higher redshift. We have many such spectra and we have been working to make them suitable for this analysis. We have concentrated on this topic since 12/15/01.

  2. Interstellar Electron Density Spectra

    NASA Astrophysics Data System (ADS)

    Lambert, Hendrick Clark

    This study concerns the investigation of the form of the wavenumber spectrum of the Galactic electron density fluctuations through an examination of the scattering of the radio pulses emitted by pulsars as they propagate through the diffuse ionized interstellar gas. A widely used model for the electron density spectrum is based on the simple power-law: Pne(q)∝ q-β, where β = 11/3 is usually assumed, corresponding to Kolmogorov's turbulence spectrum. The simple Kolmogorov model provides satisfactory agreement for observations along many lines of sight; however, major inconsistencies remain. The inconsistencies suggest that an increase in the ratio of the power between the high (10-8[ m]-1≤ q<=10-7[ m]-1) and low (10-13[ m]-1≤ q<=10-12[ m]-1) wavenumbers is needed. This enhancement in the ratio can in turn be achieved by either including an inner scale, corresponding to a dissipation scale for the turbulent cascade, in the Kolmogorov spectrum or by considering steeper spectra. Spectra with spectral exponents β > 4 have been in general rejected based on observations of pulsar refractive scintillations. The special case of β = 4 has been given little attention and is analyzed in detail. Physically, this 'β = 4' model corresponds to the random distribution, both in location and orientation, of discrete objects with relatively sharp boundaries across the line of sight. An outer scale is included in the model to account for the average size of such objects. We compare the predictions of the inner-scale and β = 4 models both with published observations and observations we made as part of this investigation. We conclude that the form of the wavenumber spectrum is dependent on the line of sight. We propose a composite spectrum featuring a uniform background turbulence in presence of randomly distributed discrete objects, as modeled by the β = model.

  3. Articular cartilage optical properties in the spectral range 300--850 nm

    NASA Astrophysics Data System (ADS)

    Ebert, Daniel W.; Roberts, Cynthia J.; Farrar, Stuart K.; Johnston, William M.; Litsky, Alan S.; Bertone, Alicia L.

    1998-07-01

    Measurements of absolute total reflectance were recorded from weight-bearing (n equals 9) and nonweight-bearing (n equals 9) equine articular cartilage specimens from 300 to 850 nm using a spectrophotometer with integrating sphere attachment. Following correction of measured spectra for interfacial reflections and edge losses, Kubelka-Munk theory was applied to estimate absorption and scattering coefficient, 1D light intensity distribution, and light penetration depth. Kubelka-Munk absorption coefficients ranged from approximately 7 cm-1 at 330 nm to approximately 1 cm-1 at 850 nm. A localized absorption peak was noted at approximately 340 nm. Above 510 nm, weight-bearing cartilage demonstrated significantly higher absorption coefficients than nonweight-bearing tissue (paired t-test, p < 0.05). Kubelka-Munk scattering coefficients ranged from approximately 40 cm-1 at 360 nm to approximately 6 cm-1 at 850 nm. No statistical differences in scattering coefficient were noted between weight-bearing and nonweight-bearing tissue. Penetration depths predicted by Kubelka-Munk theory ranged from 0.6 mm at 350 nm to over 3 mm at 850 nm. Stronger absorption in weight-bearing cartilage compared to nonweight-bearing tissue resulted in lower light penetration depths in weight-bearing cartilage at all wavelengths longer than 510 nm.

  4. Absolute absorption cross sections of ozone in the 185- to 350-nm wavelength range

    NASA Technical Reports Server (NTRS)

    Molina, L. T.; Molina, M. J.

    1986-01-01

    The absorption cross sections of ozone have been measured in the wavelength range 185-350 nm and in the temperature range 225-298 K. The absolute ozone concentrations were established by measuring the pressure of pure gaseous samples in the 0.08to 300-torr range, and the UV spectra were recorded under conditions where less than 1 percent of the sample decomposed. The temperature dependence is significant for wavelengths longer than about 280 nm. The absorption cross-section values around 210 nm were found to be about 10 percent larger than the previously accepted values.

  5. Rare-earth plasma extreme ultraviolet sources at 6.5-6.7 nm

    SciTech Connect

    Otsuka, Takamitsu; Higashiguchi, Takeshi; Yugami, Noboru; Yatagai, Toyohiko; Kilbane, Deirdre; White, John; Dunne, Padraig; O'Sullivan, Gerry; Jiang, Weihua; Endo, Akira

    2010-09-13

    We have demonstrated a laser-produced plasma extreme ultraviolet source operating in the 6.5-6.7 nm region based on rare-earth targets of Gd and Tb coupled with a Mo/B{sub 4}C multilayer mirror. Multiply charged ions produce strong resonance emission lines, which combine to yield an intense unresolved transition array. The spectra of these resonant lines around 6.7 nm (in-band: 6.7 nm {+-}1%) suggest that the in-band emission increases with increased plasma volume by suppressing the plasma hydrodynamic expansion loss at an electron temperature of about 50 eV, resulting in maximized emission.

  6. Quantum-mechanical analysis of the intensity distribution in spectra of resonant Raman scattering spectra of aqueous solutions of tyrosine

    NASA Astrophysics Data System (ADS)

    Burova, T. G.; Shcherbakov, R. S.

    2016-05-01

    Quantum-mechanical calculations of the intensity distribution in the resonant Raman scattering spectra of aqueous solutions of tyrosine excited by laser radiation with wavelengths of 244, 229, 218, 200, and 193 nm, as well as in the nonresonant Raman scattering spectrum excited at a wavelength of 488 nm, are performed. Satisfactory agreement is achieved between the calculation results and the experimental data. It is shown that the changes in the intensity distribution observed in the spectra with a change in the excitation wavelength from 244 to 193 nm correlate with the determined changes in the contribution made by excited electronic states into the scattering tensor components. It is noted that it is necessary to take into account the Herzberg-Teller effect and that the number of excited electronic states taken into account considerably affects the calculated relative intensities of lines. The possibility of existence of several tyrosine conformers in aqueous solution at room temperature is shown.

  7. Detection of munitions grade g-series nerve agents using Raman excitation at 1064 nm

    NASA Astrophysics Data System (ADS)

    Roy, Eric; Wilcox, Phillip G.; Hoffland, Soren; Pardoe, Ian

    2015-05-01

    Raman spectroscopy is a powerful tool for obtaining molecular structure information of a sample. While Raman spectroscopy is a common laboratory based analytical tool, miniaturization of opto-electronic components has allowed handheld Raman analyzers to become commercially available. These handheld systems are utilized by Military and First Responder operators tasked with rapidly identifying potentially hazardous chemicals in the field. However, one limitation of many handheld Raman detection systems is strong interference caused by fluorescence of the sample or underlying surface which obscures the characteristic Raman signature of the target analyte. Munitions grade chemical warfare agents (CWAs) are produced and stored in large batches and typically have more impurities from the storage container, degradation, or unreacted precursors. In this work, Raman spectra of munitions grade CWAs were collected using a handheld Raman spectrometer with a 1064 nm excitation laser. While Raman scattering generated by a 1064 nm laser is inherently less efficient than excitation at shorter wavelengths, high quality spectra were easily obtained due to significantly reduced fluorescence of the munitions grade CWAs. The spectra of these less pure, but more operationally relevant, munitions grade CWAs were then compared to spectra of CASARM grade CWAs, as well as Raman spectra collected using the more common 785 nm excitation laser.

  8. Photoelectron Emission Studies in CsBr at 257 nm

    SciTech Connect

    Maldonado, Juan R.; Liu, Zhi; Sun, Yun; Pianetta, Piero A.; Pease, Fabian W.; /Stanford U., Elect. Eng. Dept. /SLAC, SSRL

    2006-09-28

    CsBr/Cr photocathodes were found [1,2] to meet the requirements of a multi-electron beam lithography system operating with a light energy of 4.8 eV (257nm). The fact that photoemission was observed with a light energy below the reported 7.3 eV band gap for CsBr was not understood. This paper presents experimental results on the presence of intra-band gap absorption sites (IBAS) in CsBr thin film photo electron emitters, and presents a model based on IBAS to explain the observed photoelectron emission behavior at energies below band gap. A fluorescence band centered at 330 nm with a FWHM of about 0.34 eV was observed in CsBr/Cr samples under 257 nm laser illumination which can be attributed to IBAS and agrees well with previously obtained synchrotron photoelectron spectra[1] from the valence band of CsBr films.

  9. Electronic spectra of Fe3+ oxides and oxide hydroxides in the near IR to near UV.

    USGS Publications Warehouse

    Sherman, David M.; Waite, T.D.

    1985-01-01

    Optical absorption and diffuse reflectance spectra of several Fe2O3 and FeOOH polymorphs (hematite, maghemite, goethite, lepidocrocite) in the near-IR to near-UV spectral regions (2000-200 nm) are presented. The spectra consist primarily of Fe3+ ligand field and ligand-to-metal charge-transfer transitions.-J.A.Z.

  10. Surface Raman spectra of a biased and buried ultrathin copper phthalocyanine layer

    SciTech Connect

    Hipps, K.W.; Dowdy, J.; Hoagland, J.J. )

    1991-01-01

    Raman spectra of Al-AlO{sub x}-CuPc (1 nm)-M devices, where M = Ag or Pb, are reported. The first Raman spectrum of a material buried in a working (biased) tunnel diode without Ag surface enhancement or substrate roughening is reported. Comparison of the Raman spectra resulting from biased devices with inelastic electron tunneling spectra proves that the anomalous features of the CuPc tunneling spectrum are not due to electrochemical changes inside the device.

  11. Interpreting Chromosome Aberration Spectra

    NASA Technical Reports Server (NTRS)

    Levy, Dan; Reeder, Christopher; Loucas, Bradford; Hlatky, Lynn; Chen, Allen; Cornforth, Michael; Sachs, Rainer

    2007-01-01

    Ionizing radiation can damage cells by breaking both strands of DNA in multiple locations, essentially cutting chromosomes into pieces. The cell has enzymatic mechanisms to repair such breaks; however, these mechanisms are imperfect and, in an exchange process, may produce a large-scale rearrangement of the genome, called a chromosome aberration. Chromosome aberrations are important in killing cells, during carcinogenesis, in characterizing repair/misrepair pathways, in retrospective radiation biodosimetry, and in a number of other ways. DNA staining techniques such as mFISH ( multicolor fluorescent in situ hybridization) provide a means for analyzing aberration spectra by examining observed final patterns. Unfortunately, an mFISH observed final pattern often does not uniquely determine the underlying exchange process. Further, resolution limitations in the painting protocol sometimes lead to apparently incomplete final patterns. We here describe an algorithm for systematically finding exchange processes consistent with any observed final pattern. This algorithm uses aberration multigraphs, a mathematical formalism that links the various aspects of aberration formation. By applying a measure to the space of consistent multigraphs, we will show how to generate model-specific distributions of aberration processes from mFISH experimental data. The approach is implemented by software freely available over the internet. As a sample application, we apply these algorithms to an aberration data set, obtaining a distribution of exchange cycle sizes, which serves to measure aberration complexity. Estimating complexity, in turn, helps indicate how damaging the aberrations are and may facilitate identification of radiation type in retrospective biodosimetry.

  12. Sequencing BPS spectra

    DOE PAGES

    Gukov, Sergei; Nawata, Satoshi; Saberi, Ingmar; Stošić, Marko; Sułkowski, Piotr

    2016-03-02

    In this article, we provide both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explainmore » from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincar e polynomials in numerous examples. Among these structural properties is a novel "sliding" property, which can be explained by using (re fined) modular S-matrix. This leads to the identi fication of modular transformations in Chern-Simons theory and 3d N = 2 theory via the 3d/3d correspondence. In conclusion, we introduce the notion of associated varieties as classical limits of recursion relations of colored superpolynomials of links, and study their properties.« less

  13. Sequencing BPS spectra

    NASA Astrophysics Data System (ADS)

    Gukov, Sergei; Nawata, Satoshi; Saberi, Ingmar; Stošić, Marko; Sułkowski, Piotr

    2016-03-01

    This paper provides both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explain from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincaré polynomials in numerous examples. Among these structural properties is a novel "sliding" property, which can be explained by using (refined) modular S-matrix. This leads to the identification of modular transformations in Chern-Simons theory and 3d {N}=2 theory via the 3d/3d correspondence. Lastly, we introduce the notion of associated varieties as classical limits of recursion relations of colored superpolynomials of links, and study their properties.

  14. Spikes in Brewer spectroradiometer UV spectra

    NASA Astrophysics Data System (ADS)

    Meinander, O.; Josefsson, W.; Kaurola, J.; Koskela, T.; Lakkala, K.

    2003-04-01

    The occurrence of spikes in Brewer UV spectra has been studied. By a spike we mean an anomalous number of counts recorded in one wavelength channel causing an abrupt upwards or downwards change in value that does not originate from the true radiation signal. We have recorded downward spikes in lamp scans measured in the darkroom, and spikes occur in sky measurements as well. We analyzed continuous measurement data over several years, with more than 90 000 spectra, from one single monochromator and two double monochromator Brewers. We found that especially the double monochromators may suffer from more than 200 spikes per ~5000 annual spectra. The spikes were not always randomly distributed over the wavelength range. The single monochromator was found to have a significant number of spikes at wavelengths below 300 nm, indicating possible bias in the stray light correction unless taken into consideration. The error caused by non-corrected spikes varied greatly from case to case. For example, the effect of one moderate-size spiked was found to be more than 5 % on a DNA action dose rate and close to 1 % on a DNA action daily dose. When high accuracy of the in situ UV measurements is required, our results suggest a need to remove spikes from the spectra. We used a simple statistical approach. Other slightly different approaches exist as well. Our data showed that ancillary radiation measurements may be necessary to interpret the data correctly. Under rapidly-changing cloudiness it can be difficult to distinguish between noise spikes and the variation in irradiance due to changes in the state of the sky.

  15. Photosynthetic action spectra and adaptation to spectral light distribution in a benthic cyanobacterial mat.

    PubMed Central

    Jorgensen, B B; Cohen, Y; Des Marais, D J

    1987-01-01

    We studied adaptation to spectral light distribution in undisturbed benthic communities of cyanobacterial mats growing in hypersaline ponds at Guerrero Negro, Baja California, Mexico. Microscale measurements of oxygen photosynthesis and action spectra were performed with microelectrodes; spectral radiance was measured with fiber-optic microprobes. The spatial resolution of all measurements was 0.1 mm, and the spectral resolution was 10 to 15 nm. Light attenuation spectra showed absorption predominantly by chlorophyll a (Chl a) (430 and 670 nm), phycocyanin (620 nm), and carotenoids (440 to 500 nm). Blue light (450 nm) was attenuated 10-fold more strongly than red light (600 nm). The action spectra of the surface film of diatoms accordingly showed activity over the whole spectrum, with maxima for Chl a and carotenoids. The underlying dense Microcoleus population showed almost exclusively activity dependent upon light harvesting by phycobilins at 550 to 660 nm. Maximum activity was at 580 and 650 nm, indicating absorption by phycoerythrin and phycocyanin as well as by allophycocyanin. Very little Chl a-dependent activity could be detected in the cyanobacterial action spectrum, even with additional 600-nm light to excite photosystem II. The depth distribution of photosynthesis showed detectable activity down to a depth of 0.8 to 2.5 mm, where the downwelling radiant flux at 600 nm was reduced to 0.2 to 0.6% of the surface flux. PMID:11536572

  16. Photosynthetic action spectra and adaptation to spectral light distribution in a benthic cyanobacterial mat.

    PubMed

    Jorgensen, B B; Cohen, Y; Des Marais, D J

    1987-04-01

    We studied adaptation to spectral light distribution in undisturbed benthic communities of cyanobacterial mats growing in hypersaline ponds at Guerrero Negro, Baja California, Mexico. Microscale measurements of oxygen photosynthesis and action spectra were performed with microelectrodes; spectral radiance was measured with fiber-optic microprobes. The spatial resolution of all measurements was 0.1 mm, and the spectral resolution was 10 to 15 nm. Light attenuation spectra showed absorption predominantly by chlorophyll a (Chl a) (430 and 670 nm), phycocyanin (620 nm), and carotenoids (440 to 500 nm). Blue light (450 nm) was attenuated 10-fold more strongly than red light (600 nm). The action spectra of the surface film of diatoms accordingly showed activity over the whole spectrum, with maxima for Chl a and carotenoids. The underlying dense Microcoleus population showed almost exclusively activity dependent upon light harvesting by phycobilins at 550 to 660 nm. Maximum activity was at 580 and 650 nm, indicating absorption by phycoerythrin and phycocyanin as well as by allophycocyanin. Very little Chl a-dependent activity could be detected in the cyanobacterial action spectrum, even with additional 600-nm light to excite photosystem II. The depth distribution of photosynthesis showed detectable activity down to a depth of 0.8 to 2.5 mm, where the downwelling radiant flux at 600 nm was reduced to 0.2 to 0.6% of the surface flux.

  17. Photosynthetic action spectra and adaptation to spectral light distribution in a benthic cyanobacterial mat

    NASA Technical Reports Server (NTRS)

    Jorgensen, B. B.; Cohen, Y.; Des Marais, D. J.

    1987-01-01

    We studied adaptation to spectral light distribution in undisturbed benthic communities of cyanobacterial mats growing in hypersaline ponds at Guerrero Negro, Baja California, Mexico. Microscale measurements of oxygen photosynthesis and action spectra were performed with microelectrodes; spectral radiance was measured with fiber-optic microprobes. The spatial resolution of all measurements was 0.1 mm, and the spectral resolution was 10 to 15 nm. Light attenuation spectra showed absorption predominantly by chlorophyll a (Chl a) (430 and 670 nm), phycocyanin (620 nm), and carotenoids (440 to 500 nm). Blue light (450 nm) was attenuated 10-fold more strongly than red light (600 nm). The action spectra of the surface film of diatoms accordingly showed activity over the whole spectrum, with maxima for Chl a and carotenoids. The underlying dense Microcoleus population showed almost exclusively activity dependent upon light harvesting by phycobilins at 550 to 660 nm. Maximum activity was at 580 and 650 nm, indicating absorption by phycoerythrin and phycocyanin as well as by allophycocyanin. Very little Chl a-dependent activity could be detected in the cyanobacterial action spectrum, even with additional 600-nm light to excite photosystem II. The depth distribution of photosynthesis showed detectable activity down to a depth of 0.8 to 2.5 mm, where the downwelling radiant flux at 600 nm was reduced to 0.2 to 0.6% of the surface flux.

  18. [EPR spectra of silkworm eggs].

    PubMed

    Korkhova, E D; Chepel', L M; Nikolov, O T; Komar', I N; Shakhbazov, V G

    1976-01-01

    ESR spectra of the native grain of the silkworm have been studied in the course of embryo formation, during a diapause, and during embryo development after the diapause. It is shown that the nature of ESR spectra of the grain is not determined by the metabolic processes, but by the presence of pigments in it and other stationary biological structures having developed pi-systems and unpaired electrones. The latter are mainly found in the envelope and may give the ESR spectra, with various g-factors. A dependence of the ESR spectra integral intensity of the grain on the denotype is discovered.

  19. Simultaneous triple 914 nm, 1084 nm, and 1086 nm operation of a diode-pumped Nd:YVO4 laser

    NASA Astrophysics Data System (ADS)

    Lü, Yanfei; Xia, Jing; Liu, Huilong; Pu, Xiaoyun

    2014-10-01

    We report a diode-pumped continuous-wave (cw) triple-wavelength Nd:YVO4 laser operating at 914, 1084, and 1086 nm. A theoretical analysis has been introduced to determine the threshold conditions for simultaneous triple-wavelength laser. Using a T-shaped cavity, we realized an efficient triple-wavelength operation at 4F3/2→4I9/2 and 4F3/2→4I11/2 transitions for Nd:YVO4 crystal, simultaneously. At an absorbed pump power of 16 W (or 25 W of incident pump power), the maximum output power was 2.3 W, which included 914 nm, 1084 nm, and 1086 nm three wavelengths, and the optical conversion efficiency with respect to the absorbed pump power was 14.4%.

  20. Effects of compositional variation on absorption spectra of lunar pyroxenes

    NASA Technical Reports Server (NTRS)

    Hazen, R. M.; Bell, P. M.; Mao, H. K.

    1978-01-01

    Polarized absorption spectra of lunar pyroxenes with a range of iron, calcium, magnesium, titanium and chromium contents were measured on polished, oriented single crystals; spectral data on pure synthetic FeSiO3 were also recorded. The bands at 1 and 2 microns were found to vary significantly in position with composition within the pyroxene quadrilateral; wavelengths increased with increasing calcium and iron. In the visible region, a weak band at 640 nm correlates in intensity with Cr2O3, but not with titanium as had been previously suggested. The 505-nm ferrous iron peak is a sharp doublet in most low-calcium pyroxenes but a singlet in augites. A peak at 475 nm and an intense absorption edge below 700 nm correlated with titanium content.

  1. Sub-10 nm nanopantography

    SciTech Connect

    Tian, Siyuan Donnelly, Vincent M. E-mail: economou@uh.edu; Economou, Demetre J. E-mail: economou@uh.edu; Ruchhoeft, Paul

    2015-11-09

    Nanopantography, a massively parallel nanopatterning method over large areas, was previously shown to be capable of printing 10 nm features in silicon, using an array of 1000 nm-diameter electrostatic lenses, fabricated on the substrate, to focus beamlets of a broad area ion beam on selected regions of the substrate. In the present study, using lens dimensional scaling optimized by computer simulation, and reduction in the ion beam image size and energy dispersion, the resolution of nanopantography was dramatically improved, allowing features as small as 3 nm to be etched into Si.

  2. Fabrication of 10nm diameter carbon nanopores

    SciTech Connect

    Radenovic, Aleksandra; Trepagnier, Eliane; Csencsits, Roseann; Downing, Kenneth H; Liphardt, Jan

    2008-09-25

    The addition of carbon to samples, during imaging, presents a barrier to accurate TEM analysis, the controlled deposition of hydrocarbons by a focused electron beam can be a useful technique for local nanometer-scale sculpting of material. Here we use hydrocarbon deposition to form nanopores from larger focused ion beam (FIB) holes in silicon nitride membranes. Using this method, we close 100-200nm diameter holes to diameters of 10nm and below, with deposition rates of 0.6nm per minute. I-V characteristics of electrolytic flow through these nanopores agree quantitatively with a one dimensional model at all examined salt concentrations.

  3. Laser Damage Growth in Fused Silica with Simultaneous 351 nm and 1053 nm irradiation

    SciTech Connect

    Norton, M A; Carr, A V; Carr, C W; Donohue, E E; Feit, M D; Hollingsworth, W G; Liao, Z; Negres, R A; Rubenchik, A M; Wegner, P J

    2008-10-24

    Laser-induced growth of optical damage often determines the useful lifetime of an optic in a high power laser system. We have extended our previous work on growth of laser damage in fused silica with simultaneous 351 nm and 1053 nm laser irradiation by measuring the threshold for growth with various ratios of 351 nm and 1053 nm fluence. Previously we reported that when growth occurs, the growth rate is determined by the total fluence. We now find that the threshold for growth is dependent on both the magnitude of the 351 nm fluence as well as the ratio of the 351 nm fluence to the 1053 nm fluence. Furthermore, the data suggests that under certain conditions the 1053 nm fluence does not contribute to the growth.

  4. Catalogue of representative meteor spectra

    NASA Astrophysics Data System (ADS)

    Vojáček, V.; Borovička, J.; Koten, P.; Spurný, P.; Štork, R.

    2016-01-01

    We present a library of low-resolution meteor spectra that includes sporadic meteors, members of minor meteor showers, and major meteor showers. These meteors are in the magnitude range from +2 to ‑3, corresponding to meteoroid sizes from 1 mm to10 mm. This catalogue is available online at the CDS for those interested in video meteor spectra.

  5. Projecting Spectra for Classroom Investigations.

    ERIC Educational Resources Information Center

    Sadler, Philip

    1991-01-01

    Describes an inexpensive spectrum projector that makes high-dispersion, high-efficiency diffraction gratings using a holographic process. Discusses classroom applications such as transmission spectra, absorption spectra, reflection characteristics of materials, color mixing, florescence and phosphorescence, and break up spectral colors. (MDH)

  6. Catalogue of representative meteor spectra

    NASA Astrophysics Data System (ADS)

    Vojáček, V.; Borovička, J.; Koten, P.; Spurný, P.; Štork, R.

    2016-01-01

    We present a library of low-resolution meteor spectra that includes sporadic meteors, members of minor meteor showers, and major meteor showers. These meteors are in the magnitude range from +2 to -3, corresponding to meteoroid sizes from 1 mm to10 mm. This catalogue is available online at the CDS for those interested in video meteor spectra.

  7. Isothermal annealing of a 620 nm optical absorption band in Brazilian topaz crystals

    NASA Astrophysics Data System (ADS)

    Isotani, Sadao; Matsuoka, Masao; Albuquerque, Antonio Roberto Pereira Leite

    2013-04-01

    Isothermal decay behaviors, observed at 515, 523, 562, and 693 K, for an optical absorption band at 620 nm in gamma-irradiated Brazilian blue topaz were analyzed using a kinetic model consisting of O- bound small polarons adjacent to recombination centers (electron traps). The kinetic equations obtained on the basis of this model were solved using the method of Runge-Kutta and the fit parameters describing these defects were determined with a grid optimization method. Two activation energies of 0.52±0.08 and 0.88±0.13 eV, corresponding to two different structural configurations of the O- polarons, explained well the isothermal decay curves using first-order kinetics expected from the kinetic model. On the other hand, thermoluminescence (TL) emission spectra measured at various temperatures showed a single band at 400 nm in the temperature range of 373-553 K in which the 620 nm optical absorption band decreased in intensity. Monochromatic TL glow curve data at 400 nm extracted from the TL emission spectra observed were found to be explained reasonably by using the knowledge obtained from the isothermal decay analysis. This suggests that two different structural configurations of O- polarons are responsible for the 620 nm optical absorption band and that the thermal annealing of the polarons causes the 400 nm TL emission band.

  8. Astronomical spectra as powerful source for airglow studies

    NASA Astrophysics Data System (ADS)

    Kausch, W.; Noll, S.; Unterguggenberger, S.; Proxauf, B.; Kimeswenger, S.

    2015-03-01

    Light from astronomical objects has to pass the Earth's atmosphere before it reaches ground-based telescopes. Thus, any observation taken with such facilities contains information on the chemical composition and the physical state of the atmosphere. In particular, optical and near-infrared spectra taken with such telescopes are well suited to study various airglow emissions arising in the upper atmosphere thanks to the small field-of-view of the telescopes, large mirror sizes, and the frequent usage of medium to high resolution spectrographs. We study data taken by two frequently used echelle spectrographs from the Very Large Telescope (VLT) of the European Southern Observatory at Cerro Paranal (Chile): UVES, operative since 1999, is a high-resolution (20000 R 110000) instrument covering the wavelength range from 300 to 1100 nm. Hence, several O2 band systems (Herzberg I+II, Chamberlain, atmospheric), the green and red OI lines ( 557 nm; 630 nm), the recently discovered FeO bands ( 550 to 720 nm), NaID ( 589 nm), and all hydroxyl bands up to OH(3-0) can be investigated. The high temporal coverage allows investigations for more than one solar cycle. The X-Shooter instrument is an echelle spectrograph which is able to take medium-resolution (3000 R 18000) spectra from 300 to 2480 nm within one shot. Therefore, it is well suited for a comprehensive study of OH, as it covers all bands with a vibrational level difference 2 (up to OH(9-7)) simultaneously, apart from the previously mentioned other lines and bands. X-Shooter was put into operation in 2009. In this presentation, we will give a review on the available spectra, their quality and time coverage. Moreover, we will illustrate the potential of the data for airglow studies by showing results

  9. [Transient UV absorption spectra of artemisinin reacting with sodium hydroxide].

    PubMed

    Gao, Yan-Jun; Ping, Li; Yang, Li-Jun; Wang, Qi-Ming; Xue, Jun-Peng; Wu, Da-Cheng; Li, Rui-Xia

    2009-03-01

    UV absorption spectrum of artemisinin and transient absorption spectra of various concentrations of artemisinin reacting with sodium hydroxide were measured by using an intensified spectroscopic detector ICCD. The exposure time of each spectrum was 0.1 ms. Results indicate that artemisinin has an obvious UV absorption band centered at 212.52 nm and can react with sodium hydroxide easily. All absorption spectra of different concentrations of artemisinin reacting with sodium hydroxide have the similar changes, but the moment at which the changes happened is different. After adding sodium hydroxide into artemisinin in ethanol solution, there was a new absorption band centered at 288 nm appearing firstly. As reaction went on, the intensity of another absorption band centered at 260 nm increased gradually. At the end of the reaction, a continuous absorption band from 200 to 350 nm with the peak at 245 nm formed finally. No other transient absorption spectral data are available on the reaction of artemisinin with sodium hydroxide currently. The new spectral information obtained in this experiment provides very important experimental basis for understanding the properties of artemisinin reacting with alkaline medium and is useful for correctly using of artemisinin as a potential anticancer drug.

  10. [Study on fluorescence spectra of Chinese rice wine].

    PubMed

    Liu, Zhou-yi; Zhu, Tuo; Gu, En-dong; Liu, Ying; Song, Chun-yuan

    2008-10-01

    Chinese rice wine has a history of more than 5000 years, only in China, hich is called "Nation Wine", and Shao Xing Chinese rice wine is a representative of it. The fluorescence spectra of 3 kinds of Shao Xing Chinese rice wine with different storage age induced by suitable UV-light were obtained in the present paper through experiment. The authors compared and analyzed them comprehensively by using three dimensional contour and two dimensional fluorescence technique, and found that their best induced light was all in the vicinity of 370 nm. The peak wavelength of 3 year storage age wine was 504 nm, while 488 nm and 505 nm were for 5 and 8 year storage age wine respectively. The emitted fluorescence existed in 400 to 680 nm, which had wide peak. More over, the emitting mechanism of Shao Xing Chinese rice wine was discussed. The authors also have explained the similarity and difference of fluorescence spectra among the 3 kinds of wine. The reason for wide fluorescence peak was also analyzed. This investigation contributes to the study of the characteristic, year detection and food safety of Chinese rice wine.

  11. High-speed stimulated Brillouin scattering spectroscopy at 780 nm

    NASA Astrophysics Data System (ADS)

    Remer, Itay; Bilenca, Alberto

    2016-09-01

    We demonstrate a high-speed stimulated Brillouin scattering (SBS) spectroscopy system that is able to acquire stimulated Brillouin gain point-spectra in water samples and Intralipid tissue phantoms over 2 GHz within 10 ms and 100 ms, respectively, showing a 10-100 fold increase in acquisition rates over current frequency-domain SBS spectrometers. This improvement was accomplished by integrating an ultra-narrowband hot rubidium-85 vapor notch filter in a simplified frequency-domain SBS spectrometer comprising nearly counter-propagating continuous-wave pump-probe light at 780 nm and conventional single-modulation lock-in detection. The optical notch filter significantly suppressed stray pump light, enabling detection of stimulated Brillouin gain spectra with substantially improved acquisition times at adequate signal-to-noise ratios (˜25 dB in water samples and ˜15 dB in tissue phantoms). These results represent an important step towards the use of SBS spectroscopy for high-speed measurements of Brillouin gain resonances in scattering and non-scattering samples.

  12. Temperature measurement of wood flame based on the double line method of atomic emission spectra

    NASA Astrophysics Data System (ADS)

    Hao, Xiaojian; Liu, Zhenhua; Sang, Tao

    2016-01-01

    Aimed at the testing requirement of the transient high temperature in explosion field and the bore of barrel weapon, the temperature measurement system of double line of atomic emission spectrum was designed, the method of flame spectrum testing system were used for experimental analysis. The experimental study of wood burning spectra was done with flame spectrum testing system. The measured spectra contained atomic emission spectra of the elements K, Na, and the excitation ease of two kinds atomic emission spectra was analyzed. The temperature was calculated with two spectral lines of K I 766.5nm and 769.9nm. The results show that, compared with Na, the excitation temperature of K atomic emission spectra is lower. By double line method, the temperature of wood burning is 1040K, and error is 3.7%.

  13. Assessing the impact of hydrocarbon leakages on vegetation using reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Sanches, I. D.; Souza Filho, C. R.; Magalhães, L. A.; Quitério, G. C. M.; Alves, M. N.; Oliveira, W. J.

    2013-04-01

    This paper assesses the capability of hyperspectral remote sensing to detect hydrocarbon leakages in pipelines using vegetation status as an indicator of contamination. A field experiment in real scale and in tropical weather was conducted in which Brachiaria brizantha H.S. pasture plants were grown over soils contaminated with small volumes of liquid hydrocarbons (HCs). The contaminations involved volumes of hydrocarbons that ranged between 2 L and 12.7 L of gasoline and diesel per m3 of soil, which were applied to the crop parcels over the course of 30 days. The leaf and canopy reflectance spectra of contaminated and control plants were acquired within 350-2500 nm wavelengths. The leaf and canopy reflectance spectra were mathematically transformed by means of first derivative (FD) and continuum removal (CR) techniques. Using principal component analysis (PCA), the spectral measurements could be grouped into either two or three contamination groups. Wavelengths in the red edge were found to contain the largest spectral differences between plants at distinct, evolving contamination stages. Wavelengths centred on water absorption bands were also important to differentiating contaminated from healthy plants. The red edge position of contaminated plants, calculated on the basis of FD spectra, shifted substantially to shorter wavelengths with increasing contamination, whereas non-contaminated plants displayed a red shift (in leaf spectra) or small blue shift (in canopy spectra). At leaf scale, contaminated plants were differentiated from healthy plants between 550-750 nm, 1380-1550 nm, 1850-2000 nm and 2006-2196 nm. At canopy scale, differences were substantial between 470-518 nm, 550-750 nm, 910-1081 nm, 1116-1284 nm, 1736-1786 nm, 2006-2196 nm and 2222-2378 nm. The results of this study suggests that remote sensing of B. brizantha H.S. at both leaf and canopy scales can be used as an indicator of gasoline and diesel contaminations for the detection of small leakages

  14. Quantitative analysis of planetary reflectance spectra with principal components analysis

    NASA Technical Reports Server (NTRS)

    Johnson, P. E.; Smith, M. O.; Adams, J. B.

    1985-01-01

    A technique is presented for quantitative analysis of planetary reflectance spectra as mixtures of particles on microscopic and macroscopic scales using principal components analysis. This technique allows for determination of the endmembers being mixed, their abundance, and the scale of mixing, as well as other physical parameters. Eighteen lunar telescopic reflectance spectra of the Copernicus crater region, from 600 nm to 1800 nm in wavelength, are modeled in terms of five likely endmembers: mare basalt, mature mare soil, anorthosite, mature highland soil, and clinopyroxene. These endmembers were chosen from a similar analysis of 92 lunar soil and rock samples. The models fit the data to within 2 percent rms. It is found that the goodness of fit is marginally better for intimate mixing over macroscopic mixing.

  15. Raman spectra and optical coherent tomography images of skin

    NASA Astrophysics Data System (ADS)

    Villanueva-Luna, A. E.; Castro-Ramos, J.; Vazquez-Montiel, S.; Flores-Gil, A.; Delgado-Atencio, J. A.; Vazquez-Villa, A.

    2011-03-01

    The optical coherence tomography images are useful to see the internal profile and the structure of material samples. In this work, OCT images were recorded in 10 volunteers with different skin tone which were related to Raman spectra. The areas where we obtained OCT images and Raman spectra were a) index finger nail, b) between index finger and middle finger, c) middle finger tip, d) half of middle finger, e) the thumb finger tip and f) between index finger and thumb, areas measured were for the purpose of finding extracellular fluids with contain triglycerides, cholesterol and glucose that are reported in the literature. The excitation wavelength used for this work was 785 nm, a spectrometer of 6 cm-1 resolution. The spectral region used ranges from 300 to 1800 cm-1. We use an OCT with 930 nm of Central Wavelength, 1.6 mm of Image Depth, 6 mm of image width and 6.2 μm of axial resolution.

  16. Quantitative analysis of planetary reflectance spectra with principal components analysis

    NASA Astrophysics Data System (ADS)

    Johnson, P. E.; Smith, M. O.; Adams, J. B.

    1985-02-01

    A technique is presented for quantitative analysis of planetary reflectance spectra as mixtures of particles on microscopic and macroscopic scales using principal components analysis. This technique allows for determination of the endmembers being mixed, their abundance, and the scale of mixing, as well as other physical parameters. Eighteen lunar telescopic reflectance spectra of the Copernicus crater region, from 600 nm to 1800 nm in wavelength, are modeled in terms of five likely endmembers: mare basalt, mature mare soil, anorthosite, mature highland soil, and clinopyroxene. These endmembers were chosen from a similar analysis of 92 lunar soil and rock samples. The models fit the data to within 2 percent rms. It is found that the goodness of fit is marginally better for intimate mixing over macroscopic mixing.

  17. Radiometric calibration of spacecraft using small lunar images

    USGS Publications Warehouse

    Kieffer, Hugh H.; Anderson, James M.; Becker, Kris J.

    1999-01-01

    In this study, the data reduction steps that can be used to extract the lunar irradiance from low resolution images of the Moon are examined and the attendant uncertainties are quantitatively assessed. The response integrated over an image is compared to a lunar irradiance model being developed from terrestrial multi-band photometric observations over the 350-2500 nm range.

  18. Spectral analysis on origination of the bands at 437 nm and 475.5 nm of chlorophyll fluorescence excitation spectrum in Arabidopsis chloroplasts.

    PubMed

    Zeng, Lizhang; Wang, Yongqiang; Zhou, Jun

    2016-05-01

    Chlorophyll fluorescence has been often used as an intrinsic optical molecular probe to study photosynthesis. In this study, the origin of bands at 437 and 475.5 nm in the chlorophyll fluorescence excitation spectrum for emission at 685 nm in Arabidopsis chloroplasts was investigated using various optical analysis methods. The results revealed that this fluorescence excitation spectrum was related to the absorption characteristics of pigment molecules in PSII complexes. Moreover, the excitation band centred at 475.5 nm had a blue shift, but the excitation band at 437 nm changed relatively less due to induction of non-photochemical quenching (NPQ). Furthermore, fluorescence emission spectra showed that this blue shift occurred when excitation energy transfer from both chlorophyll b (Chl b) and carotenoids (Cars) to chlorophyll a (Chl a) was blocked. These results demonstrate that the excitation band at 437 nm was mainly contributed by Chl a, while the excitation band at 475.5 nm was mainly contributed by Chl b and Cars. The chlorophyll fluorescence excitation spectrum, therefore, could serve as a useful tool to describe specific characteristics of light absorption and energy transfer between light-harvesting pigments.

  19. Remittance at a single wavelength of 390 nm to quantify epidermal melanin concentration.

    PubMed

    Verkruysse, Wim; Svaasand, Lars O; Franco, Walfre; Nelson, J Stuart

    2009-01-01

    Objective quantification of epidermal melanin concentration (EMC) should be useful in laser dermatology to determine the individual maximum safe radiant exposure (IMSRE). We propose a single-wavelength remittance measurement at 390 nm as an alternative optical method to determine EMC and IMSRE. Remittance spectra (360 to 740 nm), melanin index (MI) measurements and the transient radiometric temperature increase, DeltaT(t), upon skin irradiation with an Alexandrite laser (755 nm, 3-ms pulse duration, 6 Jcm(2)) were measured on 749 skin spots (arm and calf) on 23 volunteers (skin phototypes I to IV). Due to the shallow penetration depth and independence of blood oxygen saturation (isosbestic point), remittance at 390 nm appears to provide better estimates for EMC and IMSRE than MI. PMID:19256693

  20. SEMICONDUCTOR DEVICES: In situ growth monitoring of AlGaN/GaN distributed Bragg reflectors at 530 nm using a 633 nm laser

    NASA Astrophysics Data System (ADS)

    Feng, Wen; Lirong, Huang; Bo, Jiang; Liangzhu, Tong; Wei, Xu; Deming, Liu

    2010-09-01

    The metal-organic chemical vapor deposition (MOCVD) growth of AlGaN/GaN distributed Bragg reflectors (DBR) with a reflection peak at 530 nm was in situ monitored using 633 nm laser reflectometry. Evolutions of in situ reflected reflectivity for different kinds of AlGaN/GaN DBR were simulated by the classical transfer matrix method. Two DBR samples, which have the same parameters as the simulated structures, were grown by MOCVD. The simulated and experimental results show that it is possible to evaluate the DBR parameters from the envelope shape of the in situ reflectivity spectrum. With the help of the 633 nm laser reflectometry, a DBR light emitting diode (LED) was grown. The room temperature photoluminescence spectra show that the reflection peak of the DBR in the LED is within the design region.

  1. New Measurements of Doubly Ionized Iron Group Spectra by High Resolution Fourier Transform and Grating Spectroscopy

    NASA Technical Reports Server (NTRS)

    Smillie, D. G.; Pickering, J. C.; Blackwell-Whitehead, R. J.; Smith, Peter L.; Nave, G.

    2006-01-01

    We report new measurements of doubly ionized iron group element spectra, important in the analysis of B-type (hot) stars whose spectra they dominate. These measurements include Co III and Cr III taken with the Imperial College VUV Fourier transform (FT) spectrometer and measurements of Co III taken with the normal incidence vacuum spectrograph at NIST, below 135 nm. We report new Fe III grating spectra measurements to complement our FT spectra. Work towards transition wavelengths, energy levels and branching ratios (which, combined with lifetimes, produce oscillator strengths) for these ions is underway.

  2. The emission spectra of Ar, Kr and Xe + TEA

    NASA Astrophysics Data System (ADS)

    Suzuki, Masayo; Strock, Pierre; Sauli, Fabio; Charpak, Georges

    1987-03-01

    The emission spectra of Ar, Kr and Xe + 6% TEA gas mixtures are measured by using a single wire proportional counter as the emission source. Asymmetric emission bands are observed in the range of 270 to 350 nm, which can be attributed to the radiative deexcitation of excited TEA molecules. For the practical application of optical readout of avalanche chambers, the Ar + 2.0% TEA + 20% isobutane gas mixture is also examined, and nearly the same emission band is observed.

  3. Predicting accurate fluorescent spectra for high molecular weight polycyclic aromatic hydrocarbons using density functional theory

    NASA Astrophysics Data System (ADS)

    Powell, Jacob; Heider, Emily C.; Campiglia, Andres; Harper, James K.

    2016-10-01

    The ability of density functional theory (DFT) methods to predict accurate fluorescence spectra for polycyclic aromatic hydrocarbons (PAHs) is explored. Two methods, PBE0 and CAM-B3LYP, are evaluated both in the gas phase and in solution. Spectra for several of the most toxic PAHs are predicted and compared to experiment, including three isomers of C24H14 and a PAH containing heteroatoms. Unusually high-resolution experimental spectra are obtained for comparison by analyzing each PAH at 4.2 K in an n-alkane matrix. All theoretical spectra visually conform to the profiles of the experimental data but are systematically offset by a small amount. Specifically, when solvent is included the PBE0 functional overestimates peaks by 16.1 ± 6.6 nm while CAM-B3LYP underestimates the same transitions by 14.5 ± 7.6 nm. These calculated spectra can be empirically corrected to decrease the uncertainties to 6.5 ± 5.1 and 5.7 ± 5.1 nm for the PBE0 and CAM-B3LYP methods, respectively. A comparison of computed spectra in the gas phase indicates that the inclusion of n-octane shifts peaks by +11 nm on average and this change is roughly equivalent for PBE0 and CAM-B3LYP. An automated approach for comparing spectra is also described that minimizes residuals between a given theoretical spectrum and all available experimental spectra. This approach identifies the correct spectrum in all cases and excludes approximately 80% of the incorrect spectra, demonstrating that an automated search of theoretical libraries of spectra may eventually become feasible.

  4. RESEARCH PAPER: Automated estimation of stellar fundamental parameters from low resolution spectra: the PLS method

    NASA Astrophysics Data System (ADS)

    Zhang, Jian-Nan; Luo, A.-Li; Zhao, Yong-Heng

    2009-06-01

    PLS (Partial Least Squares regression) is introduced into an automatic estimation of fundamental stellar spectral parameters. It extracts the most correlative spectral component to the parameters (Teff, log g and [Fe/H]), and sets up a linear regression function from spectra to the corresponding parameters. Considering the properties of stellar spectra and the PLS algorithm, we present a piecewise PLS regression method for estimation of stellar parameters, which is composed of one PLS model for Teff, and seven PLS models for log g and [Fe/H] estimation. Its performance is investigated by large experiments on flux calibrated spectra and continuum normalized spectra at different signal-to-noise ratios (SNRs) and resolutions. The results show that the piecewise PLS method is robust for spectra at the medium resolution of 0.23 nm. For low resolution 0.5 nm and 1 nm spectra, it achieves competitive results at higher SNR. Experiments using ELODIE spectra of 0.23 nm resolution illustrate that our piecewise PLS models trained with MILES spectra are efficient for O ~ G stars: for flux calibrated spectra, the systematic offsets are 3.8%, 0.14 dex, and -0.09 dex for Teff, log g and [Fe/H], with error scatters of 5.2%, 0.44 dex and 0.38 dex, respectively; for continuum normalized spectra, the systematic offsets are 3.8%, 0.12dex, and -0.13dex for Teff, log g and [Fe/H], with error scatters of 5.2%, 0.49 dex and 0.41 dex, respectively. The PLS method is rapid, easy to use and does not rely as strongly on the tightness of a parameter grid of templates to reach high precision as Artificial Neural Networks or minimum distance methods do.

  5. Interpretation of cathodoluminescence spectra obtained from carbonate gangue minerals and breccias, Right Fork area, central Tennessee zinc district

    SciTech Connect

    Kopp, O.C. . Dept. of Geological Sciences); Owen, M.R. . Dept. of Geology); Fuller, E.L. Jr. . Metals and Ceramics Div.)

    1993-03-01

    Spectral patterns (from approximately 350 nm to 750 nm) were obtained for zoned dolomite and unzoned calcite gangue, and dolostone breccia fragments from the Right Fork area in Jackson and Overton Counties, 40 km northeast of the elmwood Mine in the Central Tennessee zinc district. The materials had been analyzed for Fe, Mn, REE, and other trace elements using the synchrotron XRF probe at the National Synchrotron Light Source, Brookhaven National Laboratory. Three distinct zones in dolomite gangue (arbitrarily named zones 4, 5, and 6) could be traced throughout the entire area. The largest number of spectra were obtained for zone 4, which luminesces medium bright red to the eye. The spectra reveal broad peaks in the vicinity of 460 nm and 660 nm; however, spectral deconvolution suggests that the spectra comprise several peaks. The broad peak at 460 nm may consist of overlapping peaks at about 430 nm and 530 nm. Of special interest is the broad peak at 660 nm, which is normally assigned solely to Mn. Shoulders in the range from 700 nm to 725 nm might be due to Fe, which is generally assumed to quench Mn-activated cathodoluminescence. Note that Fe[sup 3+] produces peaks in the vicinity of 550 nm and 710 nm in plagioclase. Intensities determined for zone 4 vary by a factor of 3X and are related to both the Mn concentrations and the Fe/Mn ratios of the individual spots analyzed, even though little, if any, differences in intensity are observed by eye.

  6. Radiation Failures in Intel 14nm Microprocessors

    NASA Technical Reports Server (NTRS)

    Bossev, Dobrin P.; Duncan, Adam R.; Gadlage, Matthew J.; Roach, Austin H.; Kay, Matthew J.; Szabo, Carl; Berger, Tammy J.; York, Darin A.; Williams, Aaron; LaBel, K.; Ingalls, James D.

    2016-01-01

    In this study the 14 nm Intel Broadwell 5th generation core series 5005U-i3 and 5200U-i5 was mounted on Dell Inspiron laptops, MSI Cubi and Gigabyte Brix barebones and tested with Windows 8 and CentOS7 at idle. Heavy-ion-induced hard- and catastrophic failures do not appear to be related to the Intel 14nm Tri-Gate FinFET process. They originate from a small (9 m 140 m) area on the 32nm planar PCH die (not the CPU) as initially speculated. The hard failures seem to be due to a SEE but the exact physical mechanism has yet to be identified. Some possibilities include latch-ups, charge ion trapping or implantation, ion channels, or a combination of those (in biased conditions). The mechanism of the catastrophic failures seems related to the presence of electric power (1.05V core voltage). The 1064 nm laser mimics ionization radiation and induces soft- and hard failures as a direct result of electron-hole pair production, not heat. The 14nm FinFET processes continue to look promising for space radiation environments.

  7. 810nm, 980nm, 1470nm and 1950nm diode laser comparison: a preliminary "ex vivo" study on oral soft tissues

    NASA Astrophysics Data System (ADS)

    Fornaini, Carlo; Merigo, Elisabetta; Sozzi, Michele; Selleri, Stefano; Vescovi, Paolo; Cucinotta, Annamaria

    2015-02-01

    The introduction of diode lasers in dentistry has several advantages, mainly consisting on the reduced size, reduced cost and possibility to beam delivering by optical fibers. At the moment the two diode wavelengths normally utilized in the dental field are 810 and 980 nm for soft tissues treatments. The aim of this study was to compare the efficacy of four different diode wavelengths: 810, 980, 1470 and 1950 nm diode laser for the ablation of soft tissues. Several samples of veal tongue were exposed to the four different wavelengths, at different fluences. The internal temperature of the soft tissues, in the area close to the beam, was monitored with thermocouple during the experiment. The excision quality of the exposed samples have been characterized by means of an optical microscope. Tissue damages and the cut regularity have been evaluated on the base of established criteria. The lowest thermal increase was recorded for 1950 nm laser. Best quality and speed of incision were obtained by the same wavelength. By evaluating epithelial, stromal and vascular damages for all the used wavelengths, the best result, in terms of "tissue respect", have been obtained for 1470 and 1950 nm exposures. From the obtained results 1470 and 1950 nm diode laser showed to be the best performer wavelengths among these used in this "ex vivo" study, probably due to their greatest affinity to water.

  8. Spectrofluorimetric Determination of Beryllium by Mean Centering of Ratio Spectra.

    PubMed

    Chamsaz, Mahmoud; Samghani, Kobra; Arbab-Zavar, Mohammad Hossein; Heidari, Tahereh

    2016-07-01

    Trace amounts of beryllium has been determined by spectrofluorimetric method that used morin as fluorimetric reagent. Beryllium gives a highly fluorescent complex with morin. The excitation wavelength of morin and Be-morin complex were 410 and 430. The fluorescence spectra of morin and Be-morin complex were overlaped in excitation wavelength of 430 nm. A method based on mean centering of ratio spectra has been performed to remove the interference caused by morin as it overlaps with the Be-morin spectra. The linear range of beryllium concentration is in 0.2-200 ppb range. The parameters of detection limit and RSD were 0.18 ppb and 4.6 % respectively. This method was used for determination of beryllium in copper-beryllium alloy as a real sample. In determination of Be(II), the interference by Cu(II) was very serious, which was eliminated by adding triethanolamine. PMID:27265354

  9. [Research on clouds affecting the spectra of solar ultraviolet radiation].

    PubMed

    Zhao, Xiao-Yan; Yan, Hai-Tao; Zhen, Zhi-Qiang; Tang, Zheng-Xin; Wang, Hui

    2011-01-01

    In the present paper, using UV CCD optical multi-channel analyzer, the solar ultraviolet radiation spectra under the conditions of cloud cover were measured, and the impact of clouds on the solar ultraviolet radiation spectra were studied mostly. The results of spectral analysis showed that the intensity of solar ultraviolet radiation spectra was weakened by the clouds. The solar ultraviolet radiation spectral intensity attenuation depended on the wavelength and decreased with decreasing wavelength. The greater the cloud cover, the stronger the attenuation, The solar ultraviolet radiation spectral intensity at wavelengths below 315 nm was affected relatively less by the cloud cover. These results have more important practical applications. When we use solar ultraviolet radiation spectrum to study the atmospheric composition, we should choose the spectral band that is less affected by the atmospheric environment.

  10. Spectrofluorimetric Determination of Beryllium by Mean Centering of Ratio Spectra.

    PubMed

    Chamsaz, Mahmoud; Samghani, Kobra; Arbab-Zavar, Mohammad Hossein; Heidari, Tahereh

    2016-07-01

    Trace amounts of beryllium has been determined by spectrofluorimetric method that used morin as fluorimetric reagent. Beryllium gives a highly fluorescent complex with morin. The excitation wavelength of morin and Be-morin complex were 410 and 430. The fluorescence spectra of morin and Be-morin complex were overlaped in excitation wavelength of 430 nm. A method based on mean centering of ratio spectra has been performed to remove the interference caused by morin as it overlaps with the Be-morin spectra. The linear range of beryllium concentration is in 0.2-200 ppb range. The parameters of detection limit and RSD were 0.18 ppb and 4.6 % respectively. This method was used for determination of beryllium in copper-beryllium alloy as a real sample. In determination of Be(II), the interference by Cu(II) was very serious, which was eliminated by adding triethanolamine.

  11. Surface-enhanced vibrational spectra of 2-nitrofluorene.

    PubMed

    Carrasco-Flores, E A; Campos-Vallette, M M; Clavijo, R E

    2007-02-01

    The infrared and Raman spectra of the isolated adsorbate 2-nitrofluorene (2NF) have been registered and the spectral assignment was performed on the basis of both previous data concerning related molecules and density functional theory DFT calculations. The theoretical calculations were compared to the experimental results, obtaining a good agreement with the IR and Raman data. The surface-enhanced infrared and Raman spectra, SEIRA and SERS, of 2NF on different metal surfaces were registered; the best spectra were obtained by using the 633nm laser line. The most probable orientation and organization of the adsorbate on the surface were inferred from the reflection-absorption infrared spectrum RAIRS and SERS and SEIRA data. PMID:16859958

  12. Surface-enhanced vibrational spectra of 2-nitrofluorene

    NASA Astrophysics Data System (ADS)

    Carrasco-Flores, E. A.; Campos-Vallette, M. M.; Clavijo, R. E.

    2007-02-01

    The infrared and Raman spectra of the isolated adsorbate 2-nitrofluorene (2NF) have been registered and the spectral assignment was performed on the basis of both previous data concerning related molecules and density functional theory DFT calculations. The theoretical calculations were compared to the experimental results, obtaining a good agreement with the IR and Raman data. The surface-enhanced infrared and Raman spectra, SEIRA and SERS, of 2NF on different metal surfaces were registered; the best spectra were obtained by using the 633 nm laser line. The most probable orientation and organization of the adsorbate on the surface were inferred from the reflection-absorption infrared spectrum RAIRS and SERS and SEIRA data.

  13. Ocean color spectra measured off the Oregon coast - Characteristic vectors

    NASA Technical Reports Server (NTRS)

    Mueller, J. L.

    1976-01-01

    The ocean color spectrum is defined as the ratio of the spectrum of light upwelled from the sea to the spectrum of light incident on the sea surface. Ocean color spectra, observed from an airplane flown over waters off Oregon, are analyzed. The original spectra are resolved into fifty-five wavelength bands, each 5 nm wide. The shapes of these spectra are parameterized by, and shown to be accurately recoverable from, their first four principal components. These components are the scalar projections of each spectrum on the first four characteristic vectors of the sample covariance matrix. Regression equations are found with which phytoplankton pigment concentration and water transparency may be estimated as linear functions of the principal components. Pigment concentration estimates thus obtained are imprecise. The poor fit is at least partly due to the inappropriateness of the linear regression model and the neglect of other optically important substances typically present in sea water.

  14. Laboratory Measurements of the 940, 1130, and 1370 nm Water Vapor Absorption Band Profiles

    NASA Technical Reports Server (NTRS)

    Giver, Lawrence P.; Gore, Warren J.; Pilewskie, P.; Freedman, R. S.; Chackerian, C., Jr.; Varanasi, P.

    2001-01-01

    We have used the solar spectral flux radiometer (SSFR) flight instrument with the Ames 25 meter base-path White cell to obtain about 20 moderate resolution (8 nm) pure water vapor spectra from 650 to 1650 nm, with absorbing paths from 806 to 1506 meters and pressures up to 14 torr. We also obtained a set at 806 meters with several different air-broadening pressures. Model simulations were made for the 940, 1130, and 1370 nm absorption bands for some of these laboratory conditions using the Rothman, et al HITRAN-2000 linelist. This new compilation of HITRAN includes new intensity measurements for the 940 nm region. We compared simulations for our spectra of this band using HITRAN-2000 with simulations using the prior HITRAN-1996. The simulations of the 1130 nm band show about 10% less absorption than we measured. There is some evidence that the total intensity of this band is about 38% stronger than the sum of the HITRAN line intensities in this region. In our laboratory conditions the absorption depends approximately on the square root of the intensity. Thus, our measurements agree that the band is stronger than tabulated in HITRAN, but by about 20%, substantially less than the published value. Significant differences have been shown between Doppler-limited resolution spectra of the 1370 nm band obtained at the Pacific Northwest National Laboratory and HITRAN simulations. Additional new intensity measurements in this region are continuing to be made. We expect the simulations of our SSFR lab data of this band will show the relative importance of improving the HITRAN line intensities of this band for atmospheric measurements.

  15. Diode laser (980nm) cartilage reshaping

    NASA Astrophysics Data System (ADS)

    El Kharbotly, A.; El Tayeb, T.; Mostafa, Y.; Hesham, I.

    2011-03-01

    Loss of facial or ear cartilage due to trauma or surgery is a major challenge to the otolaryngologists and plastic surgeons as the complicated geometric contours are difficult to be animated. Diode laser (980 nm) has been proven effective in reshaping and maintaining the new geometric shape achieved by laser. This study focused on determining the optimum laser parameters needed for cartilage reshaping with a controlled water cooling system. Harvested animal cartilages were angulated with different degrees and irradiated with different diode laser powers (980nm, 4x8mm spot size). The cartilage specimens were maintained in a deformation angle for two hours after irradiation then released for another two hours. They were serially measured and photographed. High-power Diode laser irradiation with water cooling is a cheep and effective method for reshaping the cartilage needed for reconstruction of difficult situations in otorhinolaryngologic surgery. Key words: cartilage,diode laser (980nm), reshaping.

  16. Resist materials for 157-nm lithography

    NASA Astrophysics Data System (ADS)

    Toriumi, Minoru; Ishikawa, Seiichi; Miyoshi, Seiro; Naito, Takuya; Yamazaki, Tamio; Watanabe, Manabu; Itani, Toshiro

    2001-08-01

    Fluoropolymers are key materials for single layer resists of 157nm lithography. We have been studying fluoropolymers to identify their potential for base resins of 157nm photoresist. Many fluoropolymers showed high optical transparencies, with absorption coefficients of 0.01micrometers -1 to 2micrometers -1 at 157nm, and dry- etching resistance comparable to an ArF resist, and non- swelling solubility in the standard developer. Positive- tone resists were formulated using fluoropolymers that fulfill practical resist requirements. They showed good sensitivities, from 1 mJ/cm(superscript 2 to 10 mJ/cm2, and contrast in the sensitivity curves. They were able to be patterned using a F2 laser microstepper.

  17. Analyzing LED-induced haemal fluorescent spectra on laboratory small albino rat

    NASA Astrophysics Data System (ADS)

    Gao, Shumei; Luo, Xiaosen; Lan, Xiufeng; Jiao, Fangxiang; Lu, Jian; Ni, Xiaowu; Xu, Jiaying; Lu, Shiyue; Shen, Jian; Liu, Jiangang

    2002-04-01

    Native fluorescence spectral characteristics of red blood cells were studied in the visible region in this paper. Blood samples were collected from normal small albino rats. Native fluorescence spectra of the erythrocyte were induced using Light Emitting Diode (LED) at yellow wavelength about 570+/- 16 nm ((Delta) (lambda) 0.5approximately equals 32nm). As the rat's erythrocyte content of in physiological water is increasing, the fluorescent primary emission peak is red shifted from 588 nm to above 615 nm. Furthermore, the fluorescence intensity at about 600 nm was found to be maximal while the rat's erythrocyte consistence is 1%. Moreover, it is shown in large numbers of experiments that LED-induced fluorescence spectra of the erythrocyte are similar with the whole blood. It may make sense for low- intensity light therapy.

  18. Comparative study of Nd:KGW lasers pumped at 808 nm and 877 nm

    NASA Astrophysics Data System (ADS)

    Huang, Ke; Ge, Wen-Qi; Zhao, Tian-Zhuo; He, Jian-Guo; Feng, Chen-Yong; Fan, Zhong-Wei

    2015-10-01

    The laser performance and thermal analysis of Nd:KGW laser continuously pumped by 808 nm and 877 nm are comparatively investigated. Output power of 670 mW and 1587 mW, with nearly TEM00 mode, are achieved respectively at 808 nm pump and 877 nm pump. Meanwhile, a high-power passively Q-switched Nd:KGW/Cr4+:YAG laser pumped at 877 nm is demonstrated. An average output power of 1495 mW is obtained at pump power of 5.22 W while the laser is operating at repetition of 53.17 kHz. We demonstrate that 877 nm diode laser is a more potential pump source for Nd:KGW lasers.

  19. Kerr-gated picosecond Raman spectroscopy and Raman photon migration of equine bone tissue with 400-nm excitation

    NASA Astrophysics Data System (ADS)

    Morris, Michael D.; Goodship, Allen E.; Draper, Edward R. C.; Matousek, Pavel; Towrie, Michael; Parker, Anthony W.

    2004-07-01

    We show that Raman spectroscopy with visible lasers, even in the deep blue is possible with time-gated Raman spectroscopy. A 4 picosec time gate allows efficient fluorescence rejection, up to 1000X, and provides almost background-free Raman spectra with low incident laser power. The technology enables spectroscopy with better than 10X higher scattering efficiency than is possible with the NIR (785 nm and 830 nm) lasers that are conventionally used. Raman photon migration is shown to allow depth penetration. We show for the first time that Kerr-gated Raman spectra of bone tissue with blue laser excitation enables both fluorescence rejection and depth penetration.

  20. Tracking the photodissociation dynamics of liquid nitromethane at 266 nm by femtosecond time-resolved broadband transient grating spectroscopy

    NASA Astrophysics Data System (ADS)

    Wu, Honglin; Song, Yunfei; Yu, Guoyang; Wang, Yang; Wang, Chang; Yang, Yanqiang

    2016-05-01

    Femtosecond time-resolved transient grating (TG) technique was employed to get insight into the photodissociation mechanism of liquid nitromethane (NM). Broadband white-light continuum was introduced as the probe to observe the evolution of electronic excited states of NM molecules and the formation of photodissociation products simultaneously. The reaction channel of liquid NM under 266 nm excitation was obtained that NM molecules in excited state S2 relax through two channels: about 73% relax to low lying S1 state through S2/S1 internal conversion with a time constant of 0.24 ps and then go back to the ground state through S1/S0 internal conversion; the other 27% will dissociate with a time constant of 2.56 ps. NO2 was found to be one of the products from the experimental TG spectra, which confirmed that C-N bond rupture was the primary dissociation channel of liquid NM.

  1. Interpretation of the absorption and circular dichroic spectra of oriented purple membrane films.

    PubMed Central

    Muccio, D D; Cassim, J Y

    1979-01-01

    The absorption and circular dichroic (CD) spectra of purple membrane films in which the plane of the membranes is oriented perpendicular to the incident beam are compared with the solution spectra. This enables one to relate structural features of the purple membrane to a coordinate system as defined by a normal to the membrane plane and two mutually perpendicular in-plane axes. The film and solution absorption spectra were similar except for a relative depression in the 200 - 225-nm region of the film spectrum. However, the CD spectra showed significant differences in the visible region, where the biphasic band in the solution spectrum was replaced by a single positive band at 555 nm in the film spectrum and in the far ultraviolet region, where the 208-nm band was deleted from the film spectra of the native and regenerated membranes. Moreover, a small shoulder occurred at 208 nm in the film spectrum of the bleached membrane. The near ultraviolet spectra also showed differences, whereas the 317-nm band remained essentially the same for both spectra. Based on excitonic interpretations of the visible and far ultraviolet spectra the following conclusions were reached: (a) a relatively strong in-plane monomeric interaction occurs between te retinyl chromophore and apoprotein; (b) the helical axes of the native and regenerated membrane proteins are oriented primarily normal to the membrane plane; and (c) the helical axes of the bleached membrane proteins are tilted more in-plane than the axes of the native or regenerated membrane. Additional conclusions were that an interaction occurs between an in-plane magnetic dipole moment of the retinyl chromophore and probably an in-plane electric dipole moment of a nearby aromatic amino acid(s), and that although the membrane is anisotropic with respect to coupling between electric and magnetic moments of the aromatic amino acids, the transition dipole moments of the aromatic amino acids are not preferentially oriented in either

  2. Near infrared absorption spectra of C{sub 60} radical cations and anions prepared simultaneously in solid argon

    SciTech Connect

    Schatz, P.N.; Gasyna, Z.; Andrews, L.

    1992-12-01

    The codeposition of C{sub 60} vapor with excess argon and concurrent argon resonance radiation has produced strong new absorptions at 973 and 1068 nm in solid argon at 11 {plus_minus} 1 K. A similar experiment with CCl{sub 4}, added to serve as an electron trap, reduced the yield of the 1068 nm band with little effect on the 973 nm absorption. The 973 nm band is assigned to C{sub 60}{sup +} produced by photoionization and the 1068 nm band to C{sub 60}{sup {minus}} formed by electron capture. These identifications are in excellent agreement with glassy matrix, solution and photoelectron spectra. Preliminary magnetic circular dichroism (MCD) spectra of the 973 nm C{sub 60}{sup +} band have also been measured. Both the 1068 and 973 nm bands show a characteristic triplet structure which is tentatively attributed to the combined effects of spin-orbit and Jahn-Teller coupling.

  3. Quick analysis of optical spectra to quantify epidermal melanin and papillary dermal blood content of skin.

    PubMed

    Jacques, Steven L

    2015-04-01

    This paper presents a practical approach for assessing the melanin and blood content of the skin from total diffuse reflectance spectra, R(λ), where λ is wavelength. A quick spectral analysis using just three wavelengths (585 nm, 700 nm and 800 nm) is presented, based on the 1985 work of Kollias and Baquer who documented epidermal melanin of skin using the slope of optical density (OD) between 620 nm and 720 nm. The paper describes the non-rectilinear character of such a quick analysis, and shows that almost any choice of two wavelengths in the 600-900 range can achieve the characterization of melanin. The extrapolation of the melanin slope to 585 nm serves as a baseline for subtraction from the OD (585 nm) to yield a blood perfusion score. Monte Carlo simulations created spectral data for a skin model with epidermis, papillary dermis and reticular dermis to illustrate the analysis.

  4. Sub-10 nm carbon nanotube transistor.

    PubMed

    Franklin, Aaron D; Luisier, Mathieu; Han, Shu-Jen; Tulevski, George; Breslin, Chris M; Gignac, Lynne; Lundstrom, Mark S; Haensch, Wilfried

    2012-02-01

    Although carbon nanotube (CNT) transistors have been promoted for years as a replacement for silicon technology, there is limited theoretical work and no experimental reports on how nanotubes will perform at sub-10 nm channel lengths. In this manuscript, we demonstrate the first sub-10 nm CNT transistor, which is shown to outperform the best competing silicon devices with more than four times the diameter-normalized current density (2.41 mA/μm) at a low operating voltage of 0.5 V. The nanotube transistor exhibits an impressively small inverse subthreshold slope of 94 mV/decade-nearly half of the value expected from a previous theoretical study. Numerical simulations show the critical role of the metal-CNT contacts in determining the performance of sub-10 nm channel length transistors, signifying the need for more accurate theoretical modeling of transport between the metal and nanotube. The superior low-voltage performance of the sub-10 nm CNT transistor proves the viability of nanotubes for consideration in future aggressively scaled transistor technologies.

  5. Radiation Tolerance of 65nm CMOS Transistors

    DOE PAGES

    Krohn, M.; Bentele, B.; Christian, D. C.; Cumalat, J. P.; Deptuch, G.; Fahim, F.; Hoff, J.; Shenai, A.; Wagner, S. R.

    2015-12-11

    We report on the effects of ionizing radiation on 65 nm CMOS transistors held at approximately -20°C during irradiation. The pattern of damage observed after a total dose of 1 Grad is similar to damage reported in room temperature exposures, but we observe less damage than was observed at room temperature.

  6. White Sands, Carrizozo Lava Beds, NM

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A truly remarkable view of White Sands and the nearby Carrizozo Lava Beds in southeast NM (33.5N, 106.5W). White Sands, site of the WW II atomic bomb development and testing facility and later post war nuclear weapons testing that can still be seen in the cleared circular patterns on the ground.

  7. Negative-tone 193-nm resists

    NASA Astrophysics Data System (ADS)

    Cho, Sungseo; Vander Heyden, Anthony; Byers, Jeff D.; Willson, C. Grant

    2000-06-01

    A great deal of progress has been made in the design of single layer positive tone resists for 193 nm lithography. Commercial samples of such materials are now available from many vendors. The patterning of certain levels of devices profits from the use of negative tone resists. There have been several reports of work directed toward the design of negative tones resists for 193 nm exposure but, none have performed as well as the positive tone systems. Polymers with alicyclic structures in the backbone have emerged as excellent platforms from which to design positive tone resists for 193 nm exposure. We now report the adaptation of this class of polymers to the design of high performance negative tone 193 nm resists. New systems have been prepared that are based on a polarity switch mechanism for modulation of the dissolution rate. The systems are based on a polar, alicyclic polymer backbone that includes a monomer bearing a glycol pendant group that undergoes the acid catalyzed pinacol rearrangement upon exposure and bake to produce the corresponding less polar ketone. This monomer was copolymerized with maleic anhydride and a norbornene bearing a bis-trifluoromethylcarbinol. The rearrangement of the copolymer was monitored by FT-IR as a function of temperature. The synthesis of the norbornene monomers will be presented together with characterization of copolymers of these monomers with maleic anhydride. The lithographic performance of the new resist system will also be presented.

  8. MEPHISTO spectromicroscope reaches 20 nm lateral resolution

    NASA Astrophysics Data System (ADS)

    De Stasio, Gelsomina; Perfetti, Luca; Gilbert, B.; Fauchoux, O.; Capozi, M.; Perfetti, P.; Margaritondo, G.; Tonner, B. P.

    1999-03-01

    The recently described tests of the synchrotron imaging photoelectron spectromicroscope MEPHISTO (Microscope à Emission de PHotoélectrons par Illumination Synchrotronique de Type Onduleur) were complemented by further resolution improvements and tests, which brought the lateral resolution down to 20 nm. Images and line plot profiles demonstrate such performance.

  9. 1541nm GmAPD LADAR system

    NASA Astrophysics Data System (ADS)

    Kutteruf, Mary R.; Lebow, Paul

    2014-06-01

    The single photon sensitivity of Geiger-mode avalanche photo diodes (GmAPDs) has facilitated the development of LADAR systems that operate at longer stand-off distances, require lower laser pulse powers and are capable of imaging through a partial obscuration. In this paper, we describe a GmAPD LADAR system which operates at the eye-safe wavelength of 1541 nm. The longer wavelength should enhance system covertness and improve haze penetration compared to systems using 1064 nm lasers. The system is comprised of a COTS 1541 nm erbium fiber laser producing 4 ns pulses at 80 kHz to 450 kHz and a COTS camera with a focal plane of 32x32 InGaAs GmAPDs band-gap optimized for 1550 nm. Laboratory characterization methodology and results are discussed. We show that accurate modeling of the system response, allows us to achieve a depth resolution which is limited by the width of the camera's time bin (.25 ns or 1.5 inches) rather than by the duration of the laser pulse (4 ns or 2 ft.). In the presence of obscuration, the depth discrimination is degraded to 6 inches but is still significantly better than that dictated by the laser pulse duration. We conclude with a discussion of future work.

  10. A principal component analysis of transmission spectra of wine distillates

    NASA Astrophysics Data System (ADS)

    Rogovaya, M. V.; Sinitsyn, G. V.; Khodasevich, M. A.

    2014-11-01

    A chemometric method of decomposing multidimensional data into a small-sized space, the principal component method, has been applied to the transmission spectra of vintage Moldovan wine distillates. A sample of 42 distillates aged from four to 7 years from six producers has been used to show the possibility of identifying a producer in a two-dimensional space of principal components describing 94.5% of the data-matrix dispersion. Analysis of the loads into the first two principal components has shown that, in order to measure the optical characteristics of the samples under study using only two wavelengths, it is necessary to select 380 and 540 nm, instead of the standard 420 and 520 nm, to describe the variability of the distillates by one principal component or 370 and 520 nm to describe the variability by two principal components.

  11. Absorption spectra of crystalline limestones experimentally deformed or tectonised

    NASA Astrophysics Data System (ADS)

    Cervelle, B.; ChayéD'Albissin, M.; Gouet, G.; Visocekas, R.

    1982-11-01

    Diffuse-reflectance spectra have been measured for a series of samples of Carrara marble experimentally deformed under different cylindrical stress ( P = 0, 100, 250, 500, 980 bars). The creation of point defects that results has been shown up classically by irradiation with β rays (40 krads), thus producing a typical blue coloration linked with the formation of colour centres. The diffuse-reflectance spectra, measured on powders with a microscope-spectrometer in the visible range (400-800 nm), allow the determination of the absorption spectra by means of the Kubelka-Munk function. These absorption spectra have been measured for each of the deformed samples, as well as for different fractions of a very deformed specimen subsequently heated at temperatures between 100 and 500° C for a fixed time. In the same way, tectonised crystalline limestones, of various origins, were studied without any other treatment than the irradiation with β rays. From this study the following preliminary conclusions have been drawn: (1) The absorption spectrum of an undeformed but merely irradiated specimen of crystalline limestone is practically monotonous, but in the deformed specimens a broad band of absorption appears, having a maximum at 620 nm with several shoulders, the chief of which is at 520 nm. (2) This absorption band shows the existence of colour centres, the density of which can be estimated relatively by means of the chromaticity coordinates x and y of the C.I.E. obtained from the diffuse-reflectance spectra (C.I.E. = Commission Internationale de l'Éclairage). (3) An overgrinding of calcite generates defects that have the same spectra as those produced during the experimental deformation. Consequently, in obtaining the powders of grain size 50-80 μm needed for the diffuse spectrometry, great care must be exercised. (4) For a given confining pressure, the defect density is proportional to the deformation rate. (5) One can calibrate the effect of the annealing of

  12. Stratospheric N2O mixing ratio profile from high-resolution balloon-borne solar absorption spectra and laboratory spectra near 1880/cm

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Goldman, A.; Murcray, F. J.; Murcray, D. G.; Smith, M. A. H.; Seals, R. K., Jr.; Larsen, J. C.; Rinsland, P. L.

    1982-01-01

    A nonlinear least-squares fitting procedure is used to derive the stratospheric N2O mixing ratio profile from balloon-borne solar absorption spectra and laboratory spectra near 1880/cm. The atmospheric spectra analyzed here were recorded during sunset from a float altitude of 33 km with the University of Denver's 0.02/cm resolution interferometer near Alamogordo, N.M. (33 deg N) on Oct. 10, 1979. The laboratory data are used to determine the N2O line intensities. The measurements suggest an N2O mixing ratio of 264 ppbv near 15 km, decreasing to 155 ppbv near 28 km.

  13. Stratospheric N(2)O mixing ratio profile from high-resolution balloon-borne solar absorption spectra and laboratory spectra near 1880 cm(-1).

    PubMed

    Rinsland, C P; Goldman, A; Murcray, F J; Murcray, D G; Smith, M A; Seals, R K; Larsen, J C; Rinsland, P L

    1982-12-01

    A nonlinear least-squares fitting procedure has been used to derive the stratospheric N(2)O mixing ratio profile from balloon-borne solar absorption spectra and laboratory spectra near 1880 cm(-1). The atmospheric spectra were recorded during sunset from a float altitude of 33 km with the University of Denver 0.02-cm(-1) resolution interferometer near Alamogordo, N.M. (33 degrees N), on 10 Oct. 1979. The laboratory data were used to determine the N(2)O line intensities. The measurements indicate an N(2)O mixing ratio of 264 ppbv near 15 km decreasing to 155 ppbv near 28 km. PMID:20401069

  14. Stratospheric N2O mixing ratio profile from high-resolution balloon-borne solar absorption spectra and laboratory spectra near 1880/cm

    NASA Astrophysics Data System (ADS)

    Rinsland, C. P.; Goldman, A.; Murcray, F. J.; Murcray, D. G.; Smith, M. A. H.; Seals, R. K., Jr.; Larsen, J. C.; Rinsland, P. L.

    1982-12-01

    A nonlinear least-squares fitting procedure is used to derive the stratospheric N2O mixing ratio profile from balloon-borne solar absorption spectra and laboratory spectra near 1880/cm. The atmospheric spectra analyzed here were recorded during sunset from a float altitude of 33 km with the University of Denver's 0.02/cm resolution interferometer near Alamogordo, N.M. (33 deg N) on Oct. 10, 1979. The laboratory data are used to determine the N2O line intensities. The measurements suggest an N2O mixing ratio of 264 ppbv near 15 km, decreasing to 155 ppbv near 28 km.

  15. Complex Spectra in Fusion Plasmas

    NASA Astrophysics Data System (ADS)

    von Hellermann, M. G.; Bertschinger, G.; Biel, W.; Giroud, C.; Jaspers, R.; Jupen, C.; Marchuk, O.; O'Mullane, M.; Summers, H. P.; Whiteford, A.; Zastrow, K.-D.

    2005-01-01

    The need for quantitative evaluation of complex line emission spectra as observed in hot fusion plasmas initiated a challenging development of sophisticated interpretation tools based on integrating advanced atomic modelling with detailed treatment of the plasma environment. The successful merging of the two worlds has led to routine diagnostic procedures which have contributed enormously to the understanding of underlying plasma processes and also to a wide acceptance of spectroscopy as a reliable diagnostic method. In this paper three characteristic types of spectra of current and continuing interest are presented. The first is that of medium/heavy species with many ionisation stages revealed in survey VUV and XUV spectra. Such species occur as control gases, as wall materials, as ablated heavy species and possible as layered wall dopants for monitoring erosion. The spectra are complex with line-like and quasi-continuum regions and are amenable to advanced `pattern recognition' methods. The second type is of few electron, highly ionised systems observed as line-of-sight integrated passive emission spectra in the soft x-ray region. They are analysed successfully in terms of plasma parameters through matching of observation with predicted synthetic spectra. Examples used here include highly resolved helium-like emission spectra of argon, iron and titanium observed on the tokamaks TEXTOR and Tore Supra. The third type, and the emphasis of this work, comprises spectra linked to active beam spectroscopy, that is, charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES). In this case, a complex spectrum is again composed of a (usually) dominating active spectrum and an underlying passive emission spectrum. Its analysis requires modelling of both active and passive features. Examples used here are from the CXRS diagnostic at JET and TEXTOR. They display characteristic features of the main light impurity ions (C+6, He+2, N+7, Ne+10 and Ar+18

  16. Investigation of formalin influence over hard and soft biological tissues fluorescent spectra in vitro

    NASA Astrophysics Data System (ADS)

    Borisova, E.; Uzunov, Tz.; Vladimirov, B.; Avramov, L.

    2007-05-01

    In order to investigate the formalin influence over fluorescence properties of hard and soft biological tissues during conservation, emission spectra have been registered. Nitrogen laser at 337 nm and light-emitting diode with maximum at 405 nm have been used as excitation sources. For investigation of formalin influence over hard tissues, an experiment was made on teeth samples. Sound teeth were demineralized with a phosphoric acid for 10 seconds to obtain enamel structure near to the tooth lesion, and were fixed in formalin. Before and after teeth treatment spectra from the areas of interest were detected. There were not observed changes in the shape of the teeth spectra, related to the introduction of formalin fluorescence. Samples from mucosa of esophagus and stomach, where initially an ALA/Protoporphyrin IX diagnosis was applied, were used as soft tissue specimens. After fluorescent diagnosis in vivo biopsy samples were obtained from normal and cancerous areas and were conserved in formalin. Initially, spectrum observed has one autofluorescence maximum from the mucous tissue at 500-600 nm and secondary maxima from the protoporphyrin fluorescence at 635 nm and 720 nm, as well as pronounced minima at 540 and 575 nm related to hemoglobin absorption. After formalin conservation hemoglobin absorption was strongly reduced that increases mucous emission signal in green-yellow spectral region. Simultaneously the maxima at 635 nm and 720 nm were reduced. As conclusion we could say that formalin has negligible influence over fluorescence spectra of conserved hard tissues and has more pronounced influence over fluorescence spectra obtained in the case of soft tissue conservation, which has to be taking into account in measurements in vitro.

  17. Tip-Enhanced Raman Spectroscopy and Microscopy on Single Dye Molecules with 15nm Resolution

    NASA Astrophysics Data System (ADS)

    Steidtner, Jens; Pettinger, Bruno

    2008-06-01

    Our recently developed approach of UHV-tip-enhanced Raman spectroscopy permits us to acquire Raman spectra of a few single brilliant cresyl blue (BCB) molecules and even a single one adsorbed on a Au(111) surface. This is substantiated by simultaneously recorded STM images. Furthermore, because of the reduced photobleaching in UHV, the time frame for spectral acquisition is sufficiently extended to allow tip-enhanced Raman imaging of a single BCB molecule with a lateral resolution of 15 nm.

  18. Optical properties of human colon tissues in the 350 – 2500 nm spectral range

    SciTech Connect

    Bashkatov, A N; Genina, E A; Kochubey, V I; Kolesnikova, E A; Tuchin, V V; Rubtsov, V S

    2014-08-31

    We present the optical characteristics of the mucosa and submucosa of human colon tissue. The experiments are performed in vitro using a LAMBDA 950 spectrophotometer in the 350 – 2500 nm spectral range. The absorption and scattering coefficients and the scattering anisotropy factor are calculated based on the measured diffuse reflectance and total and collimated transmittance spectra using the inverse Monte Carlo method. (laser biophotonics)

  19. VizieR Online Data Catalog: Thorium spectrum from 250nm to 5500nm (Redman+, 2014)

    NASA Astrophysics Data System (ADS)

    Redman, S. L.; Nave, G.; Sansonetti, C. J.

    2014-04-01

    We observed the spectrum of a commercial sealed Th/Ar HCL running at 25mA for almost 15hr starting on 2011 November 2. The region of observation was limited to between 8500/cm and 28000/cm (360nm and 1200nm) by the sensitivity of the silicon photodiode detector. (5 data files).

  20. Analysis of photometric spectra of 17 meteors

    NASA Technical Reports Server (NTRS)

    Millman, P. M.

    1982-01-01

    The initial phase of the photometry which involved 17 meteor spectra consisting of eight Geminid spectra, six Orionid spectra and three Eta Aquarid spectra is discussed. Among these 17 spectra it is found that the Geminid spectra are of the best quality and are used for the identification of the atomic lines and molecular bands that normally appear on video tape spectra. The data from the Geminid records are used for developing calibration techniques in photometry. The Orionid and Eta Aquarid spectra are chosen for early analysis because of the current interest in all physical and chemical data relating to Comet Halley.

  1. 120 nm resolution and 55 nm structure size in STED-lithography.

    PubMed

    Wollhofen, Richard; Katzmann, Julia; Hrelescu, Calin; Jacak, Jaroslaw; Klar, Thomas A

    2013-05-01

    Two-photon direct laser writing (DLW) lithography is limited in the achievable structure size as well as in structure resolution. Adding stimulated emission depletion (STED) to DLW allowed overcoming both restrictions. We now push both to new limits. Using visible light for two-photon DLW (780 nm) and STED (532 nm), we obtain lateral structure sizes of 55 nm, a Sparrow limit of around 100 nm and we present two clearly separated lines spaced only 120 nm apart. The photo-resist used in these experiments is a mixture of tri- and tetra-acrylates and 7-Diethylamino-3-thenoylcoumarin as a photo-starter which can be readily quenched via STED.

  2. Photoresist outgassing at 157 nm exposure

    NASA Astrophysics Data System (ADS)

    Hien, Stefan; Angood, Steve; Ashworth, Dominic; Basset, Steve; Bloomstein, Theodore M.; Dean, Kim R.; Kunz, Roderick R.; Miller, Daniel A.; Patel, Shashikant; Rich, Georgia K.

    2001-08-01

    Contamination of optical elements during photoresist exposure is a serious issue in optical lithography. The outgassing of photoresist has been identified as a problem at 248nm and 193nm in production because the organic films that can be formed on an exposure lens can cause transmission loss and sever image distortion. At these exposure energies, the excitation of the photo acid generator, formation of acid, and cleavage of the protecting group are highly selective processes. At 157nm, the exposure energy is much higher (7.9 eV compared to 6.4 eV at 193nm) and it is known from laser ablation experiments that direct laser cleavage of sigma bonds occurs. The fragments formed during this irradiation can be considered as effective laser deposition precursors even in the mid ppb level. In this study, methods to quantify photoresist outgassing at 157 nm are discussed. Three criteria have been set up at International SEMATECH to protect lens contamination and to determine the severity of photoresist outgassing. First, we measured film thickness loss as a function of exposure dose for a variety of materials. In a second test we studied the molecular composition of the outgassing fragments with an exposure chamber coupled to a gas chromatograph and a mass spectrometer detector. Our third method was a deposition test of outgassing vapors on a CaF2 proof plate followed by analysis using VUV and X-ray photoelectron spectroscopies (XPS). With this technique we found deposits for many different resists. Our main focus is on F- and Si- containing resists. Both material classes form deposits especially if these atoms are bound to the polymer side chains. Whereas the F-containing films can be cleaned off under 157nm irradiation, cleaning of Si-containing films mainly produces SiO2. Our cleaning studies of plasma deposited F-containing organic films on SiO2 did not indicate damage of this surface by the possible formation of HF. Despite that we strongly recommend engineering

  3. Reduction of multielement mass spectra

    SciTech Connect

    Russ, G.P. III; Caffee, M.W.; Hudson, G.B.; Storch, N.A.

    1990-06-29

    Even though the spectra obtained by inductively coupled plasma source spectrometry (ICP-MS) are relatively simple, their interpretation can be complicated by the presence of molecular and isobaric interferants. To the extent that isotopic abundances are known and constant, one can treat observed spectra as sums of known components. A linear decomposition approach for determining the concentrations of the components in a spectrum and correctly propagating uncertainties is presented. This technique differs from linear regression in that an exact fit is made to a subset of isotopes and goodness-of-fit is evaluated from the deviations between the predicted and measured intensities of the other, unfit isotopes. This technique can be applied to a wide range of spectral fitting problems. In this paper, its applicability to ICP-MS spectra is used to demonstrate the use and utility of the technique. 2 refs., 9 figs.

  4. Photon spectra from WIMP annihilation

    SciTech Connect

    Cembranos, J. A. R.; Cruz-Dombriz, A. de la; Dobado, A.; Maroto, A. L.; Lineros, R. A.

    2011-04-15

    If the present dark matter in the Universe annihilates into standard model particles, it must contribute to the fluxes of cosmic rays that are detected on the Earth and, in particular, to the observed gamma-ray fluxes. The magnitude of such a contribution depends on the particular dark matter candidate, but certain features of the produced photon spectra may be analyzed in a rather model-independent fashion. In this work we provide the complete photon spectra coming from WIMP annihilation into standard model particle-antiparticle pairs obtained by extensive Monte Carlo simulations. We present results for each individual annihilation channel and provide analytical fitting formulas for the different spectra for a wide range of WIMP masses.

  5. Visible/near-infrared spectra of experimentally shocked plagioclase feldspars

    USGS Publications Warehouse

    Johnson, J. R.; Horz, F.

    2003-01-01

    High shock pressures cause structural changes in plagioclase feldspars such as mechanical fracturing and disaggregation of the crystal lattice at submicron scales, the formation of diaplectic glass (maskelynite), and genuine melting. Past studies of visible/ near-infrared spectra of shocked feldspars demonstrated few spectral variations with pressure except for a decrease in the depth of the absorption feature near 1250-1300 nm and an overall decrease in reflectance. New visible/near-infrared spectra (400-2500 nm) of experimentally shocked (17-56 GPa) albite- and anorthite-rich rock powders demonstrate similar trends, including the loss of minor hydrated mineral bands near 1410, 1930, 2250, and 2350 nm. However, the most interesting new observations are increases in reflectance at intermediate pressures, followed by subsequent decreases in reflectance at higher pressures. The amount of internal scattering and overall sample reflectance is controlled by the relative proportions of micro-fractures, submicron grains, diaplectic glass, and melts formed during shock metamorphism. We interpret the observed reflectance increases at intermediate pressures to result from progressively larger proportions of submicron feldspar grains and diaplectic glass. The ensuing decreases in reflectance occur after diaplectic glass formation is complete and the proportion of genuine melt inclusions increases. The pressure regimes over which these reflectance variations occur differ between albite and anorthite, consistent with thermal infrared spectra of these samples and previous studies of shocked feldspars. These types of spectral variations associated with different peak shock pressures should be considered during interpretation and modeling of visible/near-infrared remotely sensed spectra of planetary and asteroidal surfaces.

  6. QUALITATIVE INTERPRETATION OF GALAXY SPECTRA

    SciTech Connect

    Sanchez Almeida, J.; Morales-Luis, A. B.; Terlevich, R.; Terlevich, E.; Cid Fernandes, R. E-mail: abml@iac.es E-mail: eterlevi@inaoep.mx

    2012-09-10

    We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis and for gaining physical insight when interpreting the outputs provided by automated tools. Though the recipe is for general application, it was developed for understanding the nature of the Automatic Spectroscopic K-means-based (ASK) template spectra. They resulted from the classification of all the galaxy spectra in the Sloan Digital Sky Survey data release 7, thus being a comprehensive representation of the galaxy spectra in the local universe. Using the recipe, we give a description of the properties of the gas and the stars that characterize the ASK classes, from those corresponding to passively evolving galaxies, to H II galaxies undergoing a galaxy-wide starburst. The qualitative analysis is found to be in excellent agreement with quantitative analyses of the same spectra. We compare the mean ages of the stellar populations with those inferred using the code STARLIGHT. We also examine the estimated gas-phase metallicity with the metallicities obtained using electron-temperature-based methods. A number of byproducts follow from the analysis. There is a tight correlation between the age of the stellar population and the metallicity of the gas, which is stronger than the correlations between galaxy mass and stellar age, and galaxy mass and gas metallicity. The galaxy spectra are known to follow a one-dimensional sequence, and we identify the luminosity-weighted mean stellar age as the affine parameter that describes the sequence. All ASK classes happen to have a significant fraction of old stars, although spectrum-wise they are outshined by the youngest populations. Old stars are metal-rich or metal-poor depending on whether they reside in passive galaxies or in star-forming galaxies.

  7. Selection of Portable Spectrometers for Planetary Exploration: A Comparison of 532 nm and 785 nm Raman Spectroscopy of Reduced Carbon in Archean Cherts.

    PubMed

    Harris, Liam V; Hutchinson, Ian B; Ingley, Richard; Marshall, Craig P; Marshall, Alison Olcott; Edwards, Howell G M

    2015-06-01

    Knowledge and understanding of the martian environment has advanced greatly over the past two decades, beginning with NASA's return to the surface of Mars with the Pathfinder mission and its rover Sojourner in 1997 and continuing today with data being returned by the Curiosity rover. Reduced carbon, however, is yet to be detected on the martian surface, despite its abundance in meteorites originating from the planet. If carbon is detected on Mars, it could be a remnant of extinct life, although an abiotic source is much more likely. If the latter is the case, environmental carbonaceous material would still provide a source of carbon that could be utilized by microbial life for biochemical synthesis and could therefore act as a marker for potential habitats, indicating regions that should be investigated further. For this reason, the detection and characterization of reduced or organic carbon is a top priority for both the ESA/Roscosmos ExoMars rover, currently due for launch in 2018, and for NASA's Mars 2020 mission. Here, we present a Raman spectroscopic study of Archean chert Mars analog samples from the Pilbara Craton, Western Australia. Raman spectra were acquired with a flight-representative 532 nm instrument and a 785 nm instrument with similar operating parameters. Reduced carbon was successfully detected with both instruments; however, its Raman bands were detected more readily with 785 nm excitation, and the corresponding spectra exhibited superior signal-to-noise ratios and reduced background levels.

  8. Selection of Portable Spectrometers for Planetary Exploration: A Comparison of 532 nm and 785 nm Raman Spectroscopy of Reduced Carbon in Archean Cherts.

    PubMed

    Harris, Liam V; Hutchinson, Ian B; Ingley, Richard; Marshall, Craig P; Marshall, Alison Olcott; Edwards, Howell G M

    2015-06-01

    Knowledge and understanding of the martian environment has advanced greatly over the past two decades, beginning with NASA's return to the surface of Mars with the Pathfinder mission and its rover Sojourner in 1997 and continuing today with data being returned by the Curiosity rover. Reduced carbon, however, is yet to be detected on the martian surface, despite its abundance in meteorites originating from the planet. If carbon is detected on Mars, it could be a remnant of extinct life, although an abiotic source is much more likely. If the latter is the case, environmental carbonaceous material would still provide a source of carbon that could be utilized by microbial life for biochemical synthesis and could therefore act as a marker for potential habitats, indicating regions that should be investigated further. For this reason, the detection and characterization of reduced or organic carbon is a top priority for both the ESA/Roscosmos ExoMars rover, currently due for launch in 2018, and for NASA's Mars 2020 mission. Here, we present a Raman spectroscopic study of Archean chert Mars analog samples from the Pilbara Craton, Western Australia. Raman spectra were acquired with a flight-representative 532 nm instrument and a 785 nm instrument with similar operating parameters. Reduced carbon was successfully detected with both instruments; however, its Raman bands were detected more readily with 785 nm excitation, and the corresponding spectra exhibited superior signal-to-noise ratios and reduced background levels. PMID:26060980

  9. AVIRIS spectra of California wetlands

    NASA Technical Reports Server (NTRS)

    Gross, Michael F.; Ustin, Susan L.; Klemas, Vytautas

    1988-01-01

    Spectral data gathered by the AVIRIS from wetlands in the Suisun Bay area of California on 13 October 1987 were analyzed. Spectra representing stands of numerous vegetation types (including Sesuvium verrucosum, Scirpus acutus and Scirpus californicus, Xanthium strumarium, Cynadon dactylon, and Distichlis spicata) and soil were isolated. Despite some defects in the data, it was possible to detect vegetation features such as differences in the location of the chlorophyll red absorption maximum. Also, differences in cover type spectra were evident in other spectral regions. It was not possible to determine if the observed features represent noise, variability in canopy architecture, or chemical constituents of leaves.

  10. The structure of BPS spectra

    NASA Astrophysics Data System (ADS)

    Longhi, Pietro

    In this thesis we develop and apply novel techniques for analyzing BPS spectra of supersymmetric quantum field theories of class S. By a combination of wall-crossing, spectral networks and quiver methods we explore the BPS spectra of higher rank four-dimensional N = 2 super Yang-Mills, uncovering surprising new phenomena. Focusing on the SU(3) case, we prove the existence of wild BPS spectra in field theory, featuring BPS states of higher spin whose degeneracies grow exponentially with the energy. The occurrence of wild BPS states is surprising because it appears to be in tension with physical expectations on the behavior of the entropy as a function of the energy scale. The solution to this puzzle comes from realizing that the size of wild BPS states grows rapidly with their mass, and carefully analyzing the volume-dependence of the entropy of BPS states. We also find some interesting structures underlying wild BPS spectra, such as a Regge-like relation between the maximal spin of a BPS multiplet and the square of its mass, and the existence of a universal asymptotic distribution of spin-j irreps within a multiplet of given charge. We also extend the spectral networks construction by introducing a refinement in the topological classification of 2d-4d BPS states, and identifying their spin with a topological invariant known as the "writhe of soliton paths". A careful analysis of the 2d-4d wall-crossing behavior of this refined data reveals that it is described by motivic Kontsevich-Soibelman transformations, controlled by the Protected Spin Character, a protected deformation of the BPS index encoding the spin of BPS states. Our construction opens the way for the systematic study of refined BPS spectra in class S theories. We apply it to several examples, including ones featuring wild BPS spectra, where we find an interesting relation between spectral networks and certain functional equations. For class S theories of A 1 type, we derive an alternative technique for

  11. [Experimental study on the size spectra and emission factor of ultrafine particle from coal combustion].

    PubMed

    Sun, Zai; Yang, Wen-jun; Xie, Xiao-fang; Chen, Qiu-fang; Cai, Zhi-liang

    2014-12-01

    The emission characteristics of ultrafine particles released from pulverized coal combustion were studied, the size spectra of ultrafine particles (5.6-560 nm) were measured with FMPS (fast mobility particle sizer) on a self-built aerosol experiment platform. Meanwhile, a particle dynamic evolution model was established to obtain the particle deposition rate and the emission rate through the optimized algorithm. Finally, the emission factor was calculated. The results showed that at the beginning of particle generation, the size spectra were polydisperse and complex, the initial size spectra was mainly composed of three modes including 10 nm, 30-40 nm and 100-200 nm. Among them, the number concentration of mode around 10 nm was higher than those of other modes, the size spectrum of around 100-200 nm was lognormal distributed, with a CMD (count median diameter) of around 16 nm. Then, as time went on, the total number concentration was decayed by exponential law, the CMD first increased and then tended to be stable gradually. The calculation results showed that the emission factor of particles from coal combustion under laboratory condition was (5.54 x 10(12) ± 2.18 x 10(12)) unit x g(-1). PMID:25826918

  12. [Experimental study on the size spectra and emission factor of ultrafine particle from coal combustion].

    PubMed

    Sun, Zai; Yang, Wen-jun; Xie, Xiao-fang; Chen, Qiu-fang; Cai, Zhi-liang

    2014-12-01

    The emission characteristics of ultrafine particles released from pulverized coal combustion were studied, the size spectra of ultrafine particles (5.6-560 nm) were measured with FMPS (fast mobility particle sizer) on a self-built aerosol experiment platform. Meanwhile, a particle dynamic evolution model was established to obtain the particle deposition rate and the emission rate through the optimized algorithm. Finally, the emission factor was calculated. The results showed that at the beginning of particle generation, the size spectra were polydisperse and complex, the initial size spectra was mainly composed of three modes including 10 nm, 30-40 nm and 100-200 nm. Among them, the number concentration of mode around 10 nm was higher than those of other modes, the size spectrum of around 100-200 nm was lognormal distributed, with a CMD (count median diameter) of around 16 nm. Then, as time went on, the total number concentration was decayed by exponential law, the CMD first increased and then tended to be stable gradually. The calculation results showed that the emission factor of particles from coal combustion under laboratory condition was (5.54 x 10(12) ± 2.18 x 10(12)) unit x g(-1).

  13. Action spectra for validation of pathogen disinfection in medium-pressure ultraviolet (UV) systems.

    PubMed

    Beck, Sara E; Wright, Harold B; Hargy, Thomas M; Larason, Thomas C; Linden, Karl G

    2015-03-01

    Ultraviolet (UV) reactors used for disinfecting water and wastewater must be validated and monitored over time. The validation process requires understanding the photochemical properties of the pathogens of concern and the challenge microorganisms used to represent them. Specifically for polychromatic UV systems, the organisms' dose responses to UV light and their sensitivity across the UV spectrum must be known. This research measured the UV spectral sensitivity, called action spectra, of Cryptosporidium parvum, and MS2, T1UV, Q Beta, T7, and T7m Coliphages, as well as Bacillus pumilus spores. A tunable laser from the National Institute of Standards and Technology was used to isolate single UV wavelengths at 10 nm intervals between 210 and 290 nm. Above 240 nm, all bacteria and viruses tested exhibited a relative peak sensitivity between 260 and 270 nm. Of the coliphage, MS2 exhibited the highest relative sensitivity below 240 nm, relative to its sensitivity at 254 nm, followed by Q Beta, T1UV, T7m and T7 coliphage. B. pumilus spores were more sensitive to UV light at 220 nm than any of the coliphage. These spectra are required for calculating action spectra correction factors for medium pressure UV system validation, for matching appropriate challenge microorganisms to pathogens, and for improving UV dose monitoring. Additionally, understanding the dose response of these organisms at multiple wavelengths can improve polychromatic UV dose calculations and enable prediction of pathogen inactivation from wavelength-specific disinfection technologies such as UV light emitting diodes (LEDs).

  14. Action spectra for validation of pathogen disinfection in medium-pressure ultraviolet (UV) systems.

    PubMed

    Beck, Sara E; Wright, Harold B; Hargy, Thomas M; Larason, Thomas C; Linden, Karl G

    2015-03-01

    Ultraviolet (UV) reactors used for disinfecting water and wastewater must be validated and monitored over time. The validation process requires understanding the photochemical properties of the pathogens of concern and the challenge microorganisms used to represent them. Specifically for polychromatic UV systems, the organisms' dose responses to UV light and their sensitivity across the UV spectrum must be known. This research measured the UV spectral sensitivity, called action spectra, of Cryptosporidium parvum, and MS2, T1UV, Q Beta, T7, and T7m Coliphages, as well as Bacillus pumilus spores. A tunable laser from the National Institute of Standards and Technology was used to isolate single UV wavelengths at 10 nm intervals between 210 and 290 nm. Above 240 nm, all bacteria and viruses tested exhibited a relative peak sensitivity between 260 and 270 nm. Of the coliphage, MS2 exhibited the highest relative sensitivity below 240 nm, relative to its sensitivity at 254 nm, followed by Q Beta, T1UV, T7m and T7 coliphage. B. pumilus spores were more sensitive to UV light at 220 nm than any of the coliphage. These spectra are required for calculating action spectra correction factors for medium pressure UV system validation, for matching appropriate challenge microorganisms to pathogens, and for improving UV dose monitoring. Additionally, understanding the dose response of these organisms at multiple wavelengths can improve polychromatic UV dose calculations and enable prediction of pathogen inactivation from wavelength-specific disinfection technologies such as UV light emitting diodes (LEDs). PMID:25506761

  15. Radiation Status of Sub-65 nm Electronics

    NASA Technical Reports Server (NTRS)

    Pellish, Jonathan A.

    2011-01-01

    Ultra-scaled complementary metal oxide semiconductor (CMOS) includes commercial foundry capabilities at and below the 65 nm technology node Radiation evaluations take place using standard products and test characterization vehicles (memories, logic/latch chains, etc.) NEPP focus is two-fold: (1) Conduct early radiation evaluations to ascertain viability for future NASA missions (i.e. leverage commercial technology development). (2) Uncover gaps in current testing methodologies and mechanism comprehension -- early risk mitigation.

  16. Laser damage database at 1064 nm

    SciTech Connect

    Rainer, F.; Gonzales, R.P.; Morgan, A.J.

    1990-03-01

    In conjunction with our diversification of laser damage testing capabilities, we have expanded upon a database of threshold measurements and parameter variations at 1064 nm. This includes all tests at low pulse-repetition frequencies (PRF) ranging from single shots to 120 Hz. These tests were conducted on the Reptile laser facility since 1987 and the Variable Pulse Laser (VPL) facility since 1988. Pulse durations ranged from 1 to 16 ns. 10 refs., 14 figs.

  17. Ultraviolet spectra of minerals and rocks relevant to airless bodies

    NASA Astrophysics Data System (ADS)

    Greenspon, A.; Hibbitts, C.; Klima, R. L.; Izenberg, N. R.

    2011-12-01

    Reflectance spectroscopy from the ultraviolet (UV) through infrared is used to determine the composition of solar system objects from asteroids to gas giants. Ultraviolet spectroscopy is often used to characterize small amounts of dispersed media, for example during probing tenuous atmospheres and characterizing aurora as well as exploring atmospheric chemistry. It has also been used to characterize the compositions of solid surfaces of airless bodies such as the icy Galilean and Saturnian satellites [1,2], Mercury [3], and the Moon [3,4]. Spacecraft have obtained reflectance spectra of solid-surfaced airless bodies throughout the ultraviolet through visible (~ 100 to 750nm) that show absorption features indicative of mineral composition and processes such as space weathering. We are obtaining vacuum UV - infrared (~ 130 - 5000 nm) bidirectional reflectance spectra of minerals and rocks under vacuum and at different temperatures to increase the library of available UV reflectance spectra and to assist in the interpretation of these types of observations. Reflectance spectra of olivine and montmorillonite are consistent with those measured previously [5]. We are expanding our results to minerals relevant to Mercury, where understanding UV reflectance may prove critical for mineralogical interpretation of surface spectroscopy [6], as well as exploring the effect of hydration and temperature on UV spectra. [1] Hendrix, A.R. et al., Icarus, 135, 79-84, 1998. [2] Hendrix, A.R., and C.J. Hansen, Icarus 193, 323-333, 2008. [3] Holsclaw, G.M. et al., Icarus, 209, 179-194, 2010. [4] Gladstone, G.R. et al., Science, 330, 472-476, 2010. [5] Cloutis, E. A., Icarus, 197, 321-347, 2008. [6] Izenberg et al., AGU Fall 2011 Abstract ID: 119846

  18. Optical properties of root canal irrigants in the 300-3,000-nm wavelength region.

    PubMed

    Meire, Maarten A; Poelman, Dirk; De Moor, Roeland J

    2014-09-01

    In root canal therapy, irrigating solutions are essential to assist in debridement and disinfection. Their spread and action is often restricted by canal anatomy, requiring some form of activation. Lasers have been shown to be promising tools for this purpose (laser-activated irrigation (LAI)). For LAI to be effective, high absorption of radiation in the irrigant is essential. Although the absorption spectrum of water is well established, little is known about the optical properties of other irrigating solutions. Therefore, root canal irrigants (sodium hypochlorite (NaOCl), citric acid (CA), chlorhexidine (CHX), ethylenediaminetetraacetate (EDTA), water) were subjected to UV/Vis spectrophotometry in the 300-3,000-nm region using synthetic quartz cells with an optical path length of 1 mm. Transmission data were used to plot the transmission spectrum and calculate the absorption coefficient (α) of each irrigant. The transmission spectra of the tested solutions proved to follow the spectrum of pure water to a large extent. All tested solutions displayed absorption peaks around 1,450 nm (α ≈ 14 cm(-1)), 1,950 nm (α > 30 cm(-1)), and above 2,500 nm (α > 30 cm(-1)). NaOCl showed higher absorption than water in the UV region. Slightly higher absorption than water was noted for CHX (Corsodyl) around 513 nm and for CA between 1,600 and 1,800 nm and around 2,200 nm. The absorption in all tested solutions for wavelengths greater than 2,500 nm is very high, meaning a great potential for laser-activated irrigation. Other wavelengths eligible for LAI are located around 1,450 and 2,000 nm but require further investigation.

  19. Application of laser-induced autofluorescence spectra detection in human colorectal cancer screening

    NASA Astrophysics Data System (ADS)

    Fu, Sheng; Chia, Teck-Chee; Kwek, Leong Chuan; Diong, Cheong Hoong; Tang, Choong Leong; Choen, Francis S.; Krishnan, S. M.

    2003-10-01

    We investigated 48 normal patients and 25 diseased patients using our laser-induced autofluorescence spectra detection system during their regular colonoscopy. The colon and rectum mucosa autofluorescence were excited by 405 nm continue wavelength laser. We observed that cancer or diseased colorectal mucosa, their autofluorescence spectra are significantly different from normal area. The autofluorescence spectra intensity at about 500 nm was been used for our intensity ratio characteristics intensity for our diagnostic algorithm. The intensity ratios of RI-680/I-500 and RI-630/I-500 were performed to identify the detection area. From experimental result we concluded that both intensity ratios of RI-680/I-500 and RI-630/I-500 as guidelines can detect cancerous and polyps disease completely. Our investigation provided some useful insight for laser induced autofluorescence spectra as a diagnosis technique for clinical application.

  20. Sunlight induced chlorophyll fluorescence in the near-infrared spectral region in natural waters: Interpretation of the narrow reflectance peak around 761 nm

    NASA Astrophysics Data System (ADS)

    Lu, Yingcheng; Li, Linhai; Hu, Chuanmin; Li, Lin; Zhang, Minwei; Sun, Shaojie; Lv, Chunguang

    2016-07-01

    Sunlight induced chlorophyll a fluorescence (SICF) can be used as a probe to estimate chlorophyll a concentrations (Chl) and infer phytoplankton physiology. SICF at ˜685 nm has been widely applied to studies of natural waters. SICF around 740 nm has been demonstrated to cause a narrow reflectance peak at ˜761 nm in the reflectance spectra of terrestrial vegetation. This narrow peak has also been observed in the reflectance spectra of natural waters, but its mechanism and applications have not yet been investigated and it has often been treated as measurement artifacts. In this study, we aimed to interpret this reflectance peak at ˜761 nm and discuss its potential applications for remote monitoring of natural waters. A derivative analysis of the spectral reflectance suggests that the 761 nm peak is due to SICF. It was also found that the fluorescence line height (FLH) at 761 nm significantly and linearly correlates with Chl. FLH(761 nm) showed a tighter relationship with Chl than the relationship between FLH(˜685 nm) and Chl mainly due to weaker perturbations by nonalgal materials around 761 nm. While it is not conclusive, a combination of FLH(761 nm) and FLH(˜685 nm) might have some potentials to discriminate cyanobacteria from other phytoplankton due to their different fluorescence responses at the two wavelengths. It was further found that reflectance spectra with a 5 nm spectral resolution are adequate to capture the spectral SICF feature at ˜761 nm. These preliminary results suggest that FLH(761 nm) need to be explored more for future applications in optically complex coastal and inland waters.

  1. Scatterometry measurement precision and accuracy below 70 nm

    NASA Astrophysics Data System (ADS)

    Sendelbach, Matthew; Archie, Charles N.

    2003-05-01

    Scatterometry is a contender for various measurement applications where structure widths and heights can be significantly smaller than 70 nm within one or two ITRS generations. For example, feedforward process control in the post-lithography transistor gate formation is being actively pursued by a number of RIE tool manufacturers. Several commercial forms of scatterometry are available or under development which promise to provide satisfactory performance in this regime. Scatterometry, as commercially practiced today, involves analyzing the zeroth order reflected light from a grating of lines. Normal incidence spectroscopic reflectometry, 2-theta fixed-wavelength ellipsometry, and spectroscopic ellipsometry are among the optical techniques, while library based spectra matching and realtime regression are among the analysis techniques. All these commercial forms will find accurate and precise measurement a challenge when the material constituting the critical structure approaches a very small volume. Equally challenging is executing an evaluation methodology that first determines the true properties (critical dimensions and materials) of semiconductor wafer artifacts and then compares measurement performance of several scatterometers. How well do scatterometers track process induced changes in bottom CD and sidewall profile? This paper introduces a general 3D metrology assessment methodology and reports upon work involving sub-70 nm structures and several scatterometers. The methodology combines results from multiple metrologies (CD-SEM, CD-AFM, TEM, and XSEM) to form a Reference Measurement System (RMS). The methodology determines how well the scatterometry measurement tracks critical structure changes even in the presence of other noncritical changes that take place at the same time; these are key components of accuracy. Because the assessment rewards scatterometers that measure with good precision (reproducibility) and good accuracy, the most precise

  2. Resolution of overlapped spectra for the determination of ternary mixture using different and modified spectrophotometric methods

    NASA Astrophysics Data System (ADS)

    Moussa, Bahia Abbas; El-Zaher, Asmaa Ahmed; Mahrouse, Marianne Alphonse; Ahmed, Maha Said

    2016-08-01

    Four new spectrophotometric methods were developed, applied to resolve the overlapped spectra of a ternary mixture of [aliskiren hemifumarate (ALS)-amlodipine besylate (AM)-hydrochlorothiazide (HCT)] and to determine the three drugs in pure form and in combined dosage form. Method A depends on simultaneous determination of ALS, AM and HCT using principal component regression and partial least squares chemometric methods. In Method B, a modified isosbestic spectrophotometric method was applied for the determination of the total concentration of ALS and HCT by measuring the absorbance at 274.5 nm (isosbestic point, Aiso). On the other hand, the concentration of HCT in ternary mixture with ALS and AM could be calculated without interference using first derivative spectrophotometric method by measuring the amplitude at 279 nm (zero crossing of ALS and zero value of AM). Thus, the content of ALS was calculated by subtraction. Method C, double divisor first derivative ratio spectrophotometry (double divisor 1DD method), was based on that for the determination of one drug, the ratio spectra were obtained by dividing the absorption spectra of its different concentrations by the sum of the absorption spectra of the other two drugs as a double divisor. The first derivative of the obtained ratio spectra were then recorded using the appropriate smoothing factor. The amplitudes at 291 nm, 380 nm and 274.5 nm were selected for the determination of ALS, AM and HCT in their ternary mixture, respectively. Method D was based on mean centering of ratio spectra. The mean centered values at 287, 295.5 and 269 nm were recorded and used for the determination of ALS, AM and HCT, respectively. The developed methods were validated according to ICH guidelines and proved to be accurate, precise and selective. Satisfactory results were obtained by applying the proposed methods to the analysis of pharmaceutical dosage form.

  3. Resolution of overlapped spectra for the determination of ternary mixture using different and modified spectrophotometric methods.

    PubMed

    Moussa, Bahia Abbas; El-Zaher, Asmaa Ahmed; Mahrouse, Marianne Alphonse; Ahmed, Maha Said

    2016-08-01

    Four new spectrophotometric methods were developed, applied to resolve the overlapped spectra of a ternary mixture of [aliskiren hemifumarate (ALS)-amlodipine besylate (AM)-hydrochlorothiazide (HCT)] and to determine the three drugs in pure form and in combined dosage form. Method A depends on simultaneous determination of ALS, AM and HCT using principal component regression and partial least squares chemometric methods. In Method B, a modified isosbestic spectrophotometric method was applied for the determination of the total concentration of ALS and HCT by measuring the absorbance at 274.5nm (isosbestic point, Aiso). On the other hand, the concentration of HCT in ternary mixture with ALS and AM could be calculated without interference using first derivative spectrophotometric method by measuring the amplitude at 279nm (zero crossing of ALS and zero value of AM). Thus, the content of ALS was calculated by subtraction. Method C, double divisor first derivative ratio spectrophotometry (double divisor (1)DD method), was based on that for the determination of one drug, the ratio spectra were obtained by dividing the absorption spectra of its different concentrations by the sum of the absorption spectra of the other two drugs as a double divisor. The first derivative of the obtained ratio spectra were then recorded using the appropriate smoothing factor. The amplitudes at 291nm, 380nm and 274.5nm were selected for the determination of ALS, AM and HCT in their ternary mixture, respectively. Method D was based on mean centering of ratio spectra. The mean centered values at 287, 295.5 and 269nm were recorded and used for the determination of ALS, AM and HCT, respectively. The developed methods were validated according to ICH guidelines and proved to be accurate, precise and selective. Satisfactory results were obtained by applying the proposed methods to the analysis of pharmaceutical dosage form. PMID:27128521

  4. Polarization effects in cutaneous autofluorescent spectra

    NASA Astrophysics Data System (ADS)

    Borisova, E.; Angelova, L.; Jeliazkova, Al.; Genova, Ts.; Pavlova, E.; Troyanova, P.; Avramov, L.

    2014-05-01

    Used polarized light for fluorescence excitation one could obtain response related to the anisotropy features of extracellular matrix. The fluorophore anisotropy is attenuated during lesions' growth and level of such decrease could be correlated with the stage of tumor development. Our preliminary investigations are based on in vivo point-by-point measurements of excitation-emission matrices (EEM) from healthy volunteers skin on different ages and from different anatomical places using linear polarizer and analyzer for excitation and emission light detected. Measurements were made using spectrofluorimeter FluoroLog 3 (HORIBA Jobin Yvon, France) with fiber-optic probe in steady-state regime using excitation in the region of 280-440 nm. Three different situations were evaluated and corresponding excitation-emission matrices were developed - with parallel and perpendicular positions for linear polarizer and analyzer, and without polarization of excitation and fluorescence light detected from a forearm skin surface. The fluorescence spectra obtained reveal differences in spectral intensity, related to general attenuation, due to filtering effects of used polarizer/analyzer couple. Significant spectral shape changes were observed for the complex autofluorescence signal detected, which correlated with collagen and protein cross-links fluorescence, that could be addressed to the tissue extracellular matrix and general condition of the skin investigated, due to morphological destruction during lesions' growth. A correlation between volunteers' age and the fluorescence spectra detected was observed during our measurements. Our next step is to increase developed initial database and to evaluate all sources of intrinsic fluorescent polarization effects and found if they are significantly altered from normal skin to cancerous state of the tissue, this way to develop a non-invasive diagnostic tool for dermatological practice.

  5. cloud supersaturations and CCN spectra

    NASA Astrophysics Data System (ADS)

    Hudson, James; Noble, Stephen

    2014-05-01

    Multiple regression analysis predictions of low altitude cloud droplet concentrations based on measured CCN spectra compared much better with measured low altitude droplet concentrations than various CCN concentrations at single supersaturations (S) in two aircraft cumulus cloud projects, RICO and ICE-T. The addition of vertical velocity (W) to the single and multiple regressions showed small improvements. For RICO the multiple regression correlations were also superior to previous adiabatic model predictions of droplet concentrations also based on CCN spectra and mean W. More adiabatic cloud parcels showed only slightly better correlations than flight-averaged droplet concentrations. Results show the value of more extensive CCN spectra and the relative unimportance of W variations for determining droplet concentrations in these Caribbean cumuli. The fact that flight-averaged droplet concentrations of all low cloud data was almost as well correlated with CCN spectra as were droplet concentrations of more adiabatic cloud parcels indicates that entrainment did not significantly perturb CCN-droplet concentration relationships. As should be expected higher cloud S were determined for the cumulus clouds than for stratus clouds. Suppression of cloud S by higher CCN concentrations that had previously been observed in stratus was observed in ICE-T but not in RICO where the CCN range may have been too low for cloud S suppression. But ICE-T and a stratus project, POST, even showed this S suppression over the same limited maritime CCN range as RICO.

  6. Classical Trajectories and Quantum Spectra

    NASA Technical Reports Server (NTRS)

    Mielnik, Bogdan; Reyes, Marco A.

    1996-01-01

    A classical model of the Schrodinger's wave packet is considered. The problem of finding the energy levels corresponds to a classical manipulation game. It leads to an approximate but non-perturbative method of finding the eigenvalues, exploring the bifurcations of classical trajectories. The role of squeezing turns out decisive in the generation of the discrete spectra.

  7. Size and Purity Control of HPHT Nanodiamonds down to 1 nm

    PubMed Central

    2015-01-01

    High-pressure high-temperature (HPHT) nanodiamonds originate from grinding of diamond microcrystals obtained by HPHT synthesis. Here we report on a simple two-step approach to obtain as small as 1.1 nm HPHT nanodiamonds of excellent purity and crystallinity, which are among the smallest artificially prepared nanodiamonds ever shown and characterized. Moreover we provide experimental evidence of diamond stability down to 1 nm. Controlled annealing at 450 °C in air leads to efficient purification from the nondiamond carbon (shells and dots), as evidenced by X-ray photoelectron spectroscopy, Raman spectroscopy, photoluminescence spectroscopy, and scanning transmission electron microscopy. Annealing at 500 °C promotes, besides of purification, also size reduction of nanodiamonds down to ∼1 nm. Comparably short (1 h) centrifugation of the nanodiamonds aqueous colloidal solution ensures separation of the sub-10 nm fraction. Calculations show that an asymmetry of Raman diamond peak of sub-10 nm HPHT nanodiamonds can be well explained by modified phonon confinement model when the actual particle size distribution is taken into account. In contrast, larger Raman peak asymmetry commonly observed in Raman spectra of detonation nanodiamonds is mainly attributed to defects rather than to the phonon confinement. Thus, the obtained characteristics reflect high material quality including nanoscale effects in sub-10 nm HPHT nanodiamonds prepared by the presented method. PMID:26691647

  8. Evidence from action and fluorescence spectra that UV-induced violet-blue-green fluorescence enhances leaf photosynthesis.

    PubMed

    Mantha, S V; Johnson, G A; Day, T A

    2001-03-01

    We assessed the contribution of UV-induced violet-blue-green leaf fluorescence to photosynthesis in Poa annua, Sorghum halepense and Nerium oleander by measuring UV-induced fluorescence spectra (280-380 nm excitation, 400-550 nm emission) from leaf surfaces and determining the monochromatic UV action spectra for leaf photosynthetic O2-evolution. Peak fluorescence emission wavelengths from leaf surfaces ranged from violet (408 nm) to blue (448 nm), while excitation peaks for these maxima ranged from 333 to 344 nm. Action spectra were developed by supplementing monochromatic radiation from 280 to 440 nm, in 20 nm increments, to a visible nonsaturating background of 500 mumol m-2 s-1 photosynthetically active radiation and measuring photosynthetic O2-evolution rates. Photosynthetic rates tended to be higher with the 340 nm supplement than with higher or lower wavelength UV supplements. Comparing photosynthetic rates with the 340 nm supplement to those with the 400 nm supplement, the percentage enhancement in photosynthetic rates at 340 nm ranged from 7.8 to 9.8%. We suspect that 340 nm UV improves photosynthetic rates via fluorescence that provides violet-blue-green photons for photosynthetic energy conversion because (1) the peak excitation wavelength (340 nm) for violet-blue-green fluorescence from leaves was also the most effective UV wavelength at enhancing photosynthetic rates, and (2) the magnitude of photosynthetic enhancements attributable to supplemental 340 nm UV was well correlated (R2 = 0.90) with the apparent intensity of 340 nm UV-induced violet-blue-green fluorescence emission from leaves.

  9. Shape effects on asteroid spectra

    NASA Astrophysics Data System (ADS)

    Davalos, J.; Carvano, J.

    2014-07-01

    The objective of this work is to probe how the shape of a body like an asteroid could be modifying its observed spectra and the derived mineralogical interfaces based on spectral modeling. To model this effect, we construct an oblate ellipsoid with triangular facets, where each facet contributes to the overall reflectance. The synthetic spectra is generated by the isotropic multiple-scattering approximation (IMSA) reflectance model of Hapke (1993). First, we obtained optical constants by inverting the spectra of meteorites, obtained from the RELAB spectral database. These optical constants were found inverting the reflectance bidirectional equation of Hapke; this is made in two steps: (i) The first inversion is to find the single-scattering albedo π (ii) in the model of Hapke, this albedo is found under the regime of the geometric optics, where the particle size is much larger than the wavelength of the incident radiation. Here we assumed a constant value for the real part of the optical constant n=1.5. With these optical constants, we can construct synthetic spectra for any particle size. The phase function used is the double Henyey-Greenstein phase function and an accurate expression for the H-functions. We started with the ellipsoidal shape a=1.0, b=c=0.5 for two particle size 50 and 250 μ m, in this part, we found good differences in the BAR parameter between the two geometric models, this was done for 100 Eucrite meteorites spectra. In this first study, we found that the BAR parameter between the two models is bigger when the particle size increases. In the second part, we started with different ellipsoidal shapes and produced synthetic spectra for material with eucrite and diogenite composition with a phase angle of 20 degrees, incidence and emission angles of 10 degrees, and particle size at 250 μ m. All spectra was generated for four parameters of phase angle b=[0.2,0.4,0.6,0.8] taking the empirical relation between the phase constants of Hapke (2012

  10. 10 nm gap bowtie plasmonic apertures fabricated by modified lift-off process

    NASA Astrophysics Data System (ADS)

    Huang, I.-Chun; Holzgrafe, Jeffrey; Jensen, Russell A.; Choy, Jennifer T.; Bawendi, Moungi G.; Lončar, Marko

    2016-09-01

    Bowtie plasmonic apertures, with gap sizes down to 11 nm and silver film thickness of up to 150 nm (aspect ratio ˜14:1), were fabricated on a silicon nitride membrane. Transmission spectra feature the aperture resonances ranging from 470 to 687 nm, with quality factors around 10. The mode area of the smallest gap aperture is estimated to be as small as 0.002 (λ/n)2 using numerical modeling. Importantly, our fabrication technique, based on an e-beam lithography and a lift-off process, is scalable which allows fabrication of many devices in parallel over a relatively large area. We believe that the devices demonstrated in this work will find application in studying and engineering light-matter interactions.

  11. Gd plasma source modeling at 6.7 nm for future lithography

    SciTech Connect

    Li Bowen; Dunne, Padraig; O'Sullivan, Gerry; Higashiguchi, Takeshi; Yugami, Noboru; Otsuka, Takamitsu; Jiang, Weihua; Endo, Akira

    2011-12-05

    Plasmas containing gadolinium have been proposed as sources for next generation lithography at 6.x nm. To determine the optimum plasma conditions, atomic structure calculations have been performed for Gd{sup 11+} to Gd{sup 27+} ions which showed that n = 4 - n = 4 resonance transitions overlap in the 6.5-7.0 nm region. Plasma modeling calculations, assuming collisional-radiative equilibrium, predict that the optimum temperature for an optically thin plasma is close to 110 eV and that maximum intensity occurs at 6.76 nm under these conditions. The close agreement between simulated and experimental spectra from laser and discharge produced plasmas indicates the validity of our approach.

  12. CdTe surface roughness by Raman spectroscopy using the 830 nm wavelength.

    PubMed

    Frausto-Reyes, C; Molina-Contreras, J Rafael; Medina-Gutiérrez, C; Calixto, Sergio

    2006-09-01

    A Raman spectroscopic study was performed to detect the surface roughness of a cadmium telluride (CdTe) wafer sample, using the 514.5, 632.8 and 830.0 nm excitations wavelengths. To verify the relation between the roughness and the structure of Raman spectra, in certain zones of the sample, we measured their roughness with an atomic force microscopy. It was found that, using the 830 nm wavelength there is a direct correspondence between the spectrum structure and the surface roughness. For the others wavelengths it was found, however, that there is not a clearly correspondence between them. Our results suggest that, using the excitation wavelength of 830 nm the Raman spectroscopy can be used as an on-line roughness monitor on the CdTe growth.

  13. Photoinduced absorption and refractive-index induction in phosphosilicate fibres by radiation at 193 nm

    SciTech Connect

    Rybaltovsky, A A; Sokolov, V O; Plotnichenko, V G; Lanin, Aleksei V; Semenov, S L; Dianov, Evgenii M; Gur'yanov, A N; Khopin, V F

    2007-04-30

    The photoinduced room-temperature-stable increase in the refractive index by {approx}5x10{sup -4} at a wavelength of 1.55 {mu}m was observed in phosphosilicate fibres without their preliminary loading with molecular hydrogen. It is shown that irradiation of preliminary hydrogen-loaded fibres by an ArF laser at 193 nm enhances the efficiency of refractive-index induction by an order of magnitude. The induced-absorption spectra of preforms with a phosphosilicate glass core and optical fibres fabricated from them are studied in a broad spectral range from 150 to 5000 nm. The intense induced-absorption band ({approx}800 cm{sup -1}) at 180 nm is found, which strongly affects the formation of the induced refractive index. The quantum-chemical model of a defect related to this band is proposed. (optical fibres)

  14. The laser desorption/laser ionization mass spectra of some anti-inflammatory drugs

    NASA Astrophysics Data System (ADS)

    Milnes, John; Rogers, Kevin; Jones, Sian; Gormally, John

    1994-03-01

    The IR laser desorption/ultraviolet laser ionization time-of-flight mass spectra are reported for the anti-inflammatory drugs indomethacin, acemetacin, ibuprofen, flurbiprofen, diflunisal and mefenamic acid. It is found that the six compounds can be readily ionized by two photon absorption at a fixed wavelength of 266 nm. Mass spectra have been obtained under conditions of high ionizing irradiance and the observed fragmentation behaviour is discussed.

  15. Source spectra of seismic hum

    NASA Astrophysics Data System (ADS)

    Nishida, Kiwamu

    2014-10-01

    The observation of seismic hum from 2 to 20 mHz, also known as Earth's background free oscillations, has been established. Recent observations by broad-band seismometers show simultaneous excitation of Love waves (fundamental toroidal modes) and Rayleigh waves (fundamental spheroidal modes). The excitation amplitudes above 10 mHz can be explained by random shear traction sources on Earth's surface. With estimated source distributions, the most likely excitation mechanism is a linear coupling between ocean infragravity waves and seismic surface waves through seafloor topography. Observed Love and Rayleigh wave amplitudes below 5 mHz suggest that surface pressure sources could also contribute to their excitations, although the amplitudes have large uncertainties due to the high noise levels of the horizontal components. To quantify the observation, we develop a new method for estimation of the source spectra of random tractions on Earth's surface by modelling cross-spectra between pairs of stations. The method is to calculate synthetic cross-spectra for spatially isotropic and homogeneous excitations by random shear traction and pressure sources, and invert them with the observed cross-spectra to obtain the source spectra. We applied this method to the IRIS, ORFEUS, and F-net records from 618 stations with three components of broad-band seismometers for 2004-2011. The results show the dominance of shear traction above 5 mHz, which is consistent with past studies. Below 5 mHz, however, the spectral amplitudes of the pressure sources are comparable to those of shear traction. Observed acoustic resonance between the atmosphere and the solid Earth at 3.7 and 4.4 mHz suggests that atmospheric disturbances are responsible for the surface pressure sources, although non-linear ocean wave processes are also candidates for the pressure sources. Excitation mechanisms of seismic hum should be considered as a superposition of the processes of the solid Earth, atmosphere and ocean

  16. Variation of TMA Optical Spectra With Altitude as Observed During the JOULE-2 and HEX-2 Rocket Experiments

    NASA Astrophysics Data System (ADS)

    Hampton, D. L.; Conde, M.; Craven, J. D.

    2007-12-01

    During the JOULE-2 and HEX-2 rocket experiments a total of 7 rockets releasing tri-methyl aluminum (TMA) were launched from the Poker Flat Research Range. Four of the TMA trails were observed with a video imaging spectrograph located at Poker Flat: two during the JOULE-2 experiment in the 400 to 650 nm wavelength range, and two during the HEX-2 experiment in the 615 nm to 890 nm wavelength range. The spectrograph has an angular extent of about 10 degrees along the slit and a spectral resolution of 8 nm. The spectra show that the TMA emissions comprise a broadband continuum, with no significant narrowband emission or molecular band structure apparent. When spectra are compared for TMA released at different altitudes, the continuum shows no difference between 400 nm and 600 nm. However, at wavelengths longer than 650 nm, spectra from 100 km altitude show 20 to 40% greater intensity than spectra from 90 km, when normalized at 615 nm. Proposed mechanisms for photon production in TMA generally invoke a catalytic cycle of chemiluminescence reactions between AlO and O, O2, and in some cases OH and H2O. We report the quantitative variation in spectrum with altitude for TMA in these two releases, ongoing work to use (rarely calibrated) literature data on AlO chemiluminescent reactions to determine the most likely mechanism for photon production in TMA releases, and speculate on whether the spectrum of a TMA release can help reveal geophysical information in the upper atmosphere.

  17. Instrumentation and action spectra in light-associated diseases

    SciTech Connect

    Cripps, D.J.

    1981-07-01

    Instrumentation for studying action spectra in controls and various light-associated diseases is described. This study summarizes tests performed with a prism grating monochromator during the last 10 yr. There were 68 photodermatoses studied: xeroderma pigmentosum (XP) (1), lupus erythematosus (LE) (12), polymorphous light eruption (PLE) (23), solar urticaria (4), actinic reticuloid (2), halogenated salicylanilide photosensitivity and persistent light reactors (11), psoralen photosensitivity (6), and porphyria (9). A normal minimal erythema dose in the UVB (below 320 nm) was generally observed in polymorphous light eruption and lupus erythematosus. The most exquisite photosensitivity for delayed erythema was observed in actinic reticuloid, which in one case was 25-35 times more sensitive in the UVB range which was also observed but to a lesser extent in XP and in persistent light reactors. Persistence of erythema and edema at test sites was observed in XP, PLE, LE, and actinic reticuloid. A delay in development of erythema reaching a maximum at 72 hr was observed in XP and psoralen phototoxicity. Maximum photosensitivity occurred in solar urticaria. Three patients had peak sensitivity in the range of 310-313 nm and the 4th at 460 nm. Photosensitivity in the visible range was detected in 2 patients with solar urticaria, one with actinic reticuloid, and confirmed in 9 patients with porphyria (405 nm). Photosensitivity in the UVA (above 320 nm) occurred to some degree in all groups.

  18. Time resolved EUV spectra from Zpinching capillary discharge plasma

    NASA Astrophysics Data System (ADS)

    Jancarek, Alexandr; Nevrkla, Michal; Nawaz, Fahad

    2015-09-01

    We developed symmetrically charged driver to obtain high voltage, high current Z-pinching capillary discharge. Plasma is created by up to 70 kA, 29 ns risetime current pulse passing through a 5 mm inner diameter, 224 mm long capillary filled with gas to initial pressure in the range of 1 kPa. Due to the low inductance design of the driver, the pinch is observable directly from the measured current curve. Time-integrated and time-resolved spectra of discharge plasma radiation are recorded together with the capillary current and analyzed. The most encouraging spectra were captured in the wavelength range 8.3 ÷ 14 nm. This spectral region contains nitrogen Balmer series lines including potentially lasing NVII 2 - 3 transition. Spectral lines are identified in the NIST database using the FLY kinetic code. The line of 13.38 nm wavelength, transition NVII 2 - 3, was observed in gated, and also in time-integrated spectra for currents >60 kA. This work has been supported by the Ministry of Education, Youth and Sports of the Czech Republic grants LG13029.

  19. [Feasibility of monitoring karst standing conditions with vegetation spectra].

    PubMed

    Yue, Yue-Min; Wang, Ke-Lin; Xiong, Ying

    2012-07-01

    Karst regions are typically ecological fragile zones constrained by geological setting, which resulted in high heterogeneity of vegetation standing conditions. The karst vegetation was featured with stone, dry and high calcium carbonate content growth conditions. Based on vegetation spectral analysis and canonical correspondence analysis (CCA), the present study aimed to examine the feasibility of using vegetation spectra to monitor the heterogeneous karst standing conditions. The results showed that there were significant differences between karst vegetation and non-karst vegetation within the spectral range of 1 300-2 500 nm reflectance and 400 - 680 nm first-derivative spectra. It was found that soil moisture and calcium carbonate contents had the most significant effects on vegetation spectral features in karst regions. Ordination diagrams of CCA could distinguish the differences of karst vegetation and non-karst vegetation. Our study demonstrates that vegetation spectra are highly related to karst standing conditions and it is feasible to monitor karst standing conditions with vegetation spectral features.

  20. Patterning polymeric structures with 2 nm resolution at 3 nm half pitch in ambient conditions.

    PubMed

    Martínez, R V; Losilla, N S; Martinez, J; Huttel, Y; Garcia, R

    2007-07-01

    The miniaturization limits of electronic and mechanical devices depend on the minimum pattern periodicity that is stable in ambient conditions. Here we demonstrate an atomic force microscopy lithography that enables the patterning of 2 nm organic structures with 6 nm periodicities in air. We also demonstrate that the lithography can be up-scaled for parallel patterning. The method is based on the formation of a nanoscale octane meniscus between a sharp conductive protrusion and a silicon (100) surface. The application of a high electrical field ( approximately 10 V/nm) produces the polymerization and cross-linking of the octane molecules within the meniscus followed by their deposition. The resulting pattern periodicities are very close to the ultimate theoretical limits achievable in air ( approximately 3 nm). The chemical composition of the patterns has been characterized by photoemission spectroscopy.

  1. 981 nm Yb:KYW laser intracavity pumped at 912 nm and frequency-doubling for an emission at 490.5 nm

    NASA Astrophysics Data System (ADS)

    Lü, Y. F.; Zhang, X. H.; Xia, J.; Chen, R.; Jin, G. Y.; Wang, J. G.; Li, C. L.; Ma, Z. Y.

    2010-05-01

    We present an Yb:KY(WO4)2 (Yb:KYW) laser emitting at 981 nm intracavity pumped by a 912 nm diode-pumped Nd:GdVO4 laser. A 808 nm diode laser is used to pump the Nd:GdVO4 crystal emitting at 912 nm, and the Yb:KYW laser emitting at 981 nm intracavity pumped at 912 nm. This configuration enabled us to indirectly diode-pump this ytterbium doped crystal, and to obtain 1.12 W output power at 981 nm for 19.6 W of incident pump power at 808 nm. Furthermore, intracavity second harmonic generation has also been demonstrated with a power of 106 mW at 490.5 nm by using a LBO nonlinear crystal.

  2. Laser Induced Chlorophyll Fluorescence Spectra of Cajanus Cajan L Plant Growing Under Cadmium Stress

    NASA Astrophysics Data System (ADS)

    Gopal, Ram; Pandey, J. K.

    2010-06-01

    Laser-induced Chlorophyll fluorescence (LICF) spectra of Cajanus cajan L leaves treated with different concentrations of Cd (0.05, 0.5 and 1 mM) are recorded at 10 and 20 days after first treatment of cadmium. LICF spectra are recorded in the region of 650-780 nm using violet diode laser (405 nm). LICF spectra of plant leaves show two maxima near 685 and 730nm. Fluorescence induction kinetics (FIK) curve are recorded at 685 and 730 nm with red diode laser (635 nm) for excitation. The fluorescence intensity ratios (FIR) F685/F730 are calculated from LICF spectra and vitality index (Rfd) are determined from FIK curve. FIR and Rfd value are good stress indicator of plant health. These parameters along with chlorophyll content are used to analyze the effect of Cd on wheat plants. The result indicates that higher concentrations of Cd hazardous for photosynthetic activity and health of Arhar plants. The lower concentration of 0.05 mM shows stimulatory response up to 10 days while after 20 days this concentration also shows inhibitory response. R. Gopal, K. B. Mishra, M. Zeeshan, S. M. Prasad, and M. M. Joshi Curr. Sci., 83, 880, 2002 K. B. Mishra and R. Gopal Int. J. Rem. Sen., 29, 157, 2008 R. Maurya, S. M. Prasad, and R. Gopal J. Photochem. Photobio. C: Photochem. Rev., 9, 29, 2008

  3. Near-infrared absorption spectra of C{sub 60} radical cations and anions prepared simultaneously in solid argon

    SciTech Connect

    Gasyna, Z.; Andrews, L.; Schatz, P.N.

    1992-02-20

    The codeposition of C{sub 60} vapor with excess argon and argon resonance radiation has produced strong new absorptions at 973 and 1068 nm in solid argon at 11 {+-} 1 K. A similar experiment with CCl{sub 4} added to serve as an electron trap reduced the yield of the 1068-nm band with little effect on the 973-nm absorption. The 973-nm band is assigned to C{sub 60}{sup {sm_bullet}+} produced by photoionization and the 1068-nm band to C{sub 60}{sup {sm_bullet}-} formed by electron capture. These identifications are in excellent agreement with glassy matrix, solution, and photoelectron spectra.

  4. Deep ultraviolet (254 nm) focal plane array

    NASA Astrophysics Data System (ADS)

    Cicek, Erdem; Vashaei, Zahra; McClintock, Ryan; Razeghi, Manijeh

    2011-10-01

    We report the synthesis, fabrication and testing of a 320 × 256 focal plane array (FPA) of back-illuminated, solarblind, p-i-n, AlxGa1-xN-based detectors, fully realized within our research laboratory. We implemented a novel pulsed atomic layer deposition technique for the metalorganic chemical vapor deposition (MOCVD) growth of crackfree, thick, and high Al composition AlxGa1-xN layers. Following the growth, the wafer was processed into a 320 × 256 array of 25 μm × 25 μm pixels on a 30 μm pixel-pitch and surrounding mini-arrays. A diagnostic mini-array was hybridized to a silicon fan-out chip to allow the study of electrical and optical characteristics of discrete pixels of the FPA. At a reverse bias of 1 V, an average photodetector exhibited a low dark current density of 1.12×10-8 A/cm2. Solar-blind operation is observed throughout the array with peak detection occurring at wavelengths of 256 nm and lower and falling off three orders of magnitude by 285 nm. After indium bump deposition and dicing, the FPA is hybridized to a matching ISC 9809 readout integrated circuit (ROIC). By developing a novel masking technology, we significantly reduced the visible response of the ROIC and thus the need for external filtering to achieve solar- and visible-blind operation is eliminated. This allowed the FPA to achieve high external quantum efficiency (EQE): at 254 nm, average pixels showed unbiased peak responsivity of 75 mA/W, which corresponds to an EQE of ~37%. Finally, the uniformity of the FPA and imaging properties are investigated.

  5. Quantitative comparison of the OCT imaging depth at 1300 nm and 1600 nm

    PubMed Central

    Kodach, V. M.; Kalkman, J.; Faber, D. J.; van Leeuwen, T. G.

    2010-01-01

    One of the present challenges in optical coherence tomography (OCT) is the visualization of deeper structural morphology in biological tissues. Owing to a reduced scattering, a larger imaging depth can be achieved by using longer wavelengths. In this work, we analyze the OCT imaging depth at wavelengths around 1300 nm and 1600 nm by comparing the scattering coefficient and OCT imaging depth for a range of Intralipid concentrations at constant water content. We observe an enhanced OCT imaging depth for 1600 nm compared to 1300 nm for Intralipid concentrations larger than 4 vol.%. For higher Intralipid concentrations, the imaging depth enhancement reaches 30%. The ratio of scattering coefficients at the two wavelengths is constant over a large range of scattering coefficients and corresponds to a scattering power of 2.8 ± 0.1. Based on our results we expect for biological tissues an increase of the OCT imaging depth at 1600 nm compared to 1300 nm for samples with high scattering power and low water content. PMID:21258456

  6. Photolysis of formic acid at 355 nm

    NASA Astrophysics Data System (ADS)

    Martinez, Denhi; Bautista, Teonanacatl; Guerrero, Alfonso; Alvarez, Ignacio; Cisneros, Carmen

    2015-05-01

    Formic acid is well known as a food additive and recently an application on fuel cell technology has emerged. In this work we have studied the dissociative ionization process by multiphoton absorption of formic acid molecules at 355nm wavelength photons, using TOF spectrometry in reflectron mode (R-TOF). Some of the most abundant ionic fragments produced are studied at different settings of the laser harmonic generator. The dependence of the products on these conditions is reported. This work was supported by CONACYT Project 165410 and PAPIIT IN102613 and IN101215.

  7. 248nm silicon photoablation: Microstructuring basics

    SciTech Connect

    Poopalan, P.; Najamudin, S. H.; Wahab, Y.; Mazalan, M.

    2015-05-15

    248nm pulses from a KrF excimer laser was used to ablate a Si wafer in order to ascertain the laser pulse and energy effects for use as a microstructuring tool for MEMS fabrication. The laser pulses were varied between two different energy levels of 8mJ and 4mJ while the number of pulses for ablation was varied. The corresponding ablated depths were found to range between 11 µm and 49 µm, depending on the demagnified beam fluence.

  8. Phobos surface spectra mineralogical modeling

    NASA Astrophysics Data System (ADS)

    Pajola, M.; Lazzarin, M.; Dalle Ore, C. M.; Cruikshank, D. P.; Roush, T. L.; Pendleton, Y.; Bertini, I.; Magrin, S.; Carli, C.; La Forgia, F.; Barbieri, C.

    2014-04-01

    A mineralogical model composed of a mixture of Tagish Lake meteorite (TL) and Pyroxene Glass (PM80) was presented in [1] to explain the surface reflectance of Phobos from 0.25 to 4.0 μm. The positive results we obtained, when comparing the OSIRIS data [2] extended in wavelength to include the [3,4] spectra, forced us to perform a wider comparison between our TL-PM80 model and the CRISM and OMEGA Phobos spectra presented in [5]. Such spectra cover three different regions of interest (ROIs) situated in the Phobos sub-Mars hemisphere: the interior of the Stickney crater, its eastern rim, and its proximity terrain southeast of the Reldresal crater. We decided to vary the percentage mixture of the components of our model (80% TL, 20% PM80), between pure TL and pure PM80, by means of the radiative transfer code based on the [6] formulation of the slab approximation. Once this spectral range was derived, see Fig. 1, we attempted to compare it with the [5] spectra between 0.4 and 2.6 μm, i.e. below the thermal emitted radiation, to see if any spectral match was possible. We observed that CRISM scaled spectra above 1.10 μm fall within pure Tagish Lake composition and the [1] model. The CRISM data below 1.10 μm present more discrepancies with our models, in particular for the Stickney's rim spectrum. Nevertheless the TL and PM80 components seem to be good mineralogical candidates on Phobos. We performed the same analysis with the OMEGA data and, again, we found out that the Stickney's rim spectrum lies out of our model range, while the two remaining spectra still lie between pure TL and 80% TL - 20% PM80, but indicating that a different, more complicated mixture is expected in order to explain properly both the spectral trend and the possible absorption bands located above 2.0 μm. Within this analysis, we point out that a big fraction of TL material (modeled pure or present with a minimum percentage of 80% mixed together with 20% PM80) seems to explain Phobos spectral

  9. Low-intensity LED (625 and 405 nm) and laser (805 nm) killing of Propionibacterium acnes and Staphylococcus epidermidis

    NASA Astrophysics Data System (ADS)

    Tuchina, Elena S.; Tuchin, Valery V.

    2009-02-01

    In the present work we have investigated in vitro sensitivity of microorganisms P. acnes and S. epidermidis to action of red (625 nm and 405 nm) and infrared (805 nm) radiations in combination with photosensitizes Methylene Blue and Indocyanine Green.

  10. Electrically-pumped 850-nm micromirror VECSELs.

    SciTech Connect

    Geib, Kent Martin; Peake, Gregory Merwin; Serkland, Darwin Keith; Keeler, Gordon Arthur; Mar, Alan

    2005-02-01

    Vertical-external-cavity surface-emitting lasers (VECSELs) combine high optical power and good beam quality in a device with surface-normal output. In this paper, we describe the design and operating characteristics of an electrically-pumped VECSEL that employs a wafer-scale fabrication process and operates at 850 nm. A curved micromirror output coupler is heterogeneously integrated with AlGaAs-based semiconductor material to form a compact and robust device. The structure relies on flip-chip bonding the processed epitaxial material to an aluminum nitride mount; this heatsink both dissipates thermal energy and permits high frequency modulation using coplanar traces that lead to the VECSEL mesa. Backside emission is employed, and laser operation at 850 nm is made possible by removing the entire GaAs substrate through selective wet etching. While substrate removal eliminates absorptive losses, it simultaneously compromises laser performance by increasing series resistance and degrading the spatial uniformity of current injection. Several aspects of the VECSEL design help to mitigate these issues, including the use of a novel current-spreading n type distributed Bragg reflector (DBR). Additionally, VECSEL performance is improved through the use of a p-type DBR that is modified for low thermal resistance.

  11. DNA charge transport over 34 nm

    NASA Astrophysics Data System (ADS)

    Slinker, Jason D.; Muren, Natalie B.; Renfrew, Sara E.; Barton, Jacqueline K.

    2011-03-01

    Molecular wires show promise in nanoscale electronics, but the synthesis of uniform, long conductive molecules is a significant challenge. Deoxyribonucleic acid (DNA) of precise length, by contrast, is synthesized easily, but its conductivity over the distances required for nanoscale devices has not been explored. Here we demonstrate DNA charge transport (CT) over 34 nm in 100-mer monolayers on gold. Multiplexed gold electrodes modified with 100-mer DNA yield sizable electrochemical signals from a distal, covalent Nile Blue redox probe. Significant signal attenuation upon incorporation of a single base-pair mismatch demonstrates that CT is DNA-mediated. Efficient cleavage of these 100-mers by a restriction enzyme indicates that the DNA adopts a native conformation accessible to protein binding. Similar electron-transfer rates measured through 100-mer and 17-mer monolayers are consistent with rate-limiting electron tunnelling through the saturated carbon linker. This DNA-mediated CT distance of 34 nm surpasses that of most reports of molecular wires.

  12. Photodissociation of Methyl Iodide at 193 NM

    NASA Astrophysics Data System (ADS)

    Xu, Hong; Pratt, Stephen

    2014-05-01

    A new measurement of the photodissociation of CH3I at 193 nm is reported in which we use a combination of vacuum ultraviolet photoionization and velocity map ion imaging. The iodine photofragments are probed by single-photon ionization at photon energies above and below the photoionization threshold of I(2P3/2) . The relative I(2P3/2) and I*(2P1/2) photoionization cross sections are determined at these wavelengths by using the known branching fractions for the photodissociation at 266 nm. Velocity map ion images indicate that the branching fraction for I(2P3/2) atoms is non-zero, and yield a value of 0.07 +/- 0.01. Interestingly, the translational energy distribution extracted from the image shows that the translational energy of the I(2P3/2) fragments is significantly smaller than that of the I*(2P1/2) atoms. This observation indicates the internal rotational/vibrational energy of the CH3 co-fragment is very high in the I(2P3/2) channel. The results can be interpreted in a manner consistent with the previous measurements, and provide a more complete picture of the dissociation dynamics of this prototypical molecule. This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences under contract No. DE-AC02-06CH11357.

  13. VizieR Online Data Catalog: Spectra of KIC10661783 (Lehmann+, 2013)

    NASA Astrophysics Data System (ADS)

    Lehmann, H.; Southworth, J.; Tkachenko, A.; Pavlovski, K.

    2013-08-01

    In 2010, we obtained 26 high-resolution spectra of KIC 10661783 in seven almost consecutive nights using the Coude-echelle spectrograph at the 2-m telescope of the Thueringer Landessternwarte Tautenburg. The spectra have a resolving power of 64000 and cover the wavelength range 470-740nm. The exposure time was 30 min and the spectra have a signal-to-noise ratio of 90 on average. They were reduced using standard ESO-MIDAS packages and a routine for the calibration of the instrumental radial velocity zero-point using O2 telluric lines. (2 data files).

  14. Eigenvectors of optimal color spectra.

    PubMed

    Flinkman, Mika; Laamanen, Hannu; Tuomela, Jukka; Vahimaa, Pasi; Hauta-Kasari, Markku

    2013-09-01

    Principal component analysis (PCA) and weighted PCA were applied to spectra of optimal colors belonging to the outer surface of the object-color solid or to so-called MacAdam limits. The correlation matrix formed from this data is a circulant matrix whose biggest eigenvalue is simple and the corresponding eigenvector is constant. All other eigenvalues are double, and the eigenvectors can be expressed with trigonometric functions. Found trigonometric functions can be used as a general basis to reconstruct all possible smooth reflectance spectra. When the spectral data are weighted with an appropriate weight function, the essential part of the color information is compressed to the first three components and the shapes of the first three eigenvectors correspond to one achromatic response function and to two chromatic response functions, the latter corresponding approximately to Munsell opponent-hue directions 9YR-9B and 2BG-2R.

  15. Hierarchical analysis of molecular spectra

    SciTech Connect

    Davis, M.J.

    1996-03-01

    A novel representation of molecular spectra in terms of hierarchical trees has proven to be an important aid for the study of many significant problems in gas-phase chemical dynamics. Trees are generated from molecular spectra by monitoring the changes that occur in a spectrum as resolution is changed in a continuous manner. A tree defines a genealogy among all lines of a spectrum. This allows for a detailed understanding of the assignment of features of a spectrum that may be difficult to obtain any other way as well as an understanding of intramolecular energy transfer time scales, mechanisms, and pathways. The methodology has been applied to several problems: transition state spectroscopy, intramolecular energy transfer in highly excited molecules, high-resolution overtone spectroscopy, and the nature of the classical-quantum correspondence when there is classical chaos (``quantum chaos``).

  16. Polarized Matrix Infrared Spectra of Cyclopentadienone

    NASA Astrophysics Data System (ADS)

    Ormond, Thomas K.; Scheer, Adam M.; Ellison, G. Barney; Nimlos, Mark R.; Daily, John W.; Stanton, John F.

    2012-06-01

    We are developing a resistively-heated SiC μtubular reactor with a 100 μsec residence time to study the thermal cracking of biomass monomers. The decomposition products are identified by two independent techniques: 118.2 nm VUV photoionization mass spectrometry (PIMS) and matrix infrared spectroscopy. Many lignins thermally crack to produce cyclopentadienone (m/z 80) and its derivatives. Subsequent decomposition of these cyclopentadienones results in formation of substituted acetylenes which are known precursors to polycyclic aromatic hydrocarbons and soot. Due to its anitaromatic character, cyclopentadienone is highly reactive and presents an interesting spectroscopic system. Pyrolysis of {o}-phenylene sulfite (m/z 156) is a convenient precursor for cyclopentadienone. In this work we report the polarized matrix infrared absorption spectra of cyclopentadienone and d_4-cyclopentadienone. The PIMS results corroborate the thermal decomposition steps of phenylene sulfite. {Ab initio} coupled-cluster anharmonic force field calculations are used to guide the vibrational assignments. A. M. Scheer, C. Murkarakate, D. J. Robichaud, M. R. Nimlos, and G. B. Ellison J. Phys. Chem. A 115, 13381 (2011)

  17. Catalogue of representative meteor spectra

    NASA Astrophysics Data System (ADS)

    Vojáček, V.; Borovička, J.; Koten, P.; Spurný, P.; Štork, R.

    2015-08-01

    Aims: We present a library of low-resolution meteor spectra that includes sporadic meteors, members of minor meteor showers, and major meteor showers. These meteors are in the magnitude range from +2 to -3, corresponding to meteoroid sizes from 1 mm to 10 mm. Methods: Parallel double-station video observations allowed us to compute heliocentric orbits for all meteors. Most observations were performed during the periods of activity of major meteor showers in the years between 2006 and 2012. Spectra are classified according to relative intensities of the low-temperature emission lines of Mg, Na, and Fe. Results: Shower meteors were found to be of normal composition, except for Southern δ Aquariids and some members of the Geminid shower, neither of which have Na in the meteor spectra. Variations in Na content are typical for the Geminid shower. Three populations of Na-free mereoroids were identified. The first population are iron meteorites, which have an asteroidal-chondritic origin, but one meteoroid with low perihelion (0.11 AU) was found among the iron meteorites. The second population were Sun-approaching meteoroids in which sodium is depleted by thermal desorption. The third population were Na-free meteoroids of cometary origin. Long exposure to cosmic rays on the surface of comets in the Oort cloud and disintegration of this crust might be the origin of this population of meteoroids. Spectra (Figs. 17-30) are only, Tables 4-6 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/580/A67

  18. Accelerated Fitting of Stellar Spectra

    NASA Astrophysics Data System (ADS)

    Ting, Yuan-Sen; Conroy, Charlie; Rix, Hans-Walter

    2016-07-01

    Stellar spectra are often modeled and fitted by interpolating within a rectilinear grid of synthetic spectra to derive the stars’ labels: stellar parameters and elemental abundances. However, the number of synthetic spectra needed for a rectilinear grid grows exponentially with the label space dimensions, precluding the simultaneous and self-consistent fitting of more than a few elemental abundances. Shortcuts such as fitting subsets of labels separately can introduce unknown systematics and do not produce correct error covariances in the derived labels. In this paper we present a new approach—Convex Hull Adaptive Tessellation (chat)—which includes several new ideas for inexpensively generating a sufficient stellar synthetic library, using linear algebra and the concept of an adaptive, data-driven grid. A convex hull approximates the region where the data lie in the label space. A variety of tests with mock data sets demonstrate that chat can reduce the number of required synthetic model calculations by three orders of magnitude in an eight-dimensional label space. The reduction will be even larger for higher dimensional label spaces. In chat the computational effort increases only linearly with the number of labels that are fit simultaneously. Around each of these grid points in the label space an approximate synthetic spectrum can be generated through linear expansion using a set of “gradient spectra” that represent flux derivatives at every wavelength point with respect to all labels. These techniques provide new opportunities to fit the full stellar spectra from large surveys with 15–30 labels simultaneously.

  19. Accelerated Fitting of Stellar Spectra

    NASA Astrophysics Data System (ADS)

    Ting, Yuan-Sen; Conroy, Charlie; Rix, Hans-Walter

    2016-07-01

    Stellar spectra are often modeled and fitted by interpolating within a rectilinear grid of synthetic spectra to derive the stars’ labels: stellar parameters and elemental abundances. However, the number of synthetic spectra needed for a rectilinear grid grows exponentially with the label space dimensions, precluding the simultaneous and self-consistent fitting of more than a few elemental abundances. Shortcuts such as fitting subsets of labels separately can introduce unknown systematics and do not produce correct error covariances in the derived labels. In this paper we present a new approach—Convex Hull Adaptive Tessellation (chat)—which includes several new ideas for inexpensively generating a sufficient stellar synthetic library, using linear algebra and the concept of an adaptive, data-driven grid. A convex hull approximates the region where the data lie in the label space. A variety of tests with mock data sets demonstrate that chat can reduce the number of required synthetic model calculations by three orders of magnitude in an eight-dimensional label space. The reduction will be even larger for higher dimensional label spaces. In chat the computational effort increases only linearly with the number of labels that are fit simultaneously. Around each of these grid points in the label space an approximate synthetic spectrum can be generated through linear expansion using a set of “gradient spectra” that represent flux derivatives at every wavelength point with respect to all labels. These techniques provide new opportunities to fit the full stellar spectra from large surveys with 15-30 labels simultaneously.

  20. Variable spectra of active galaxies

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.

    1988-01-01

    The analysis of EXOSAT spectra of active galaxies are presented. The objects examined for X-ray spectral variability were MR 2251-178 and 3C 120. The results of these investigations are described, as well as additional results on X-ray spectral variability related to EXOSAT observations of active galaxies. Additionally, the dipping X-ray source 4U1624-49 was also investigated.

  1. Theoretical prediction of vibrational spectra

    NASA Astrophysics Data System (ADS)

    Niu, Zefu; Dunn, Kevin M.; Boggs, James E.

    The complete harmonic force field and the diagonal and first off-diagonal cubic constants of aniline have been calculated ab initio using a 4-21 basis set augmented by addition of d functions to the nitrogen atom. The force constants were then scaled using scale factors optimized previously to give the best fit to the similarly computed vibrational spectra of benzene and its deuterated isotopomers. The vibrational spectra of aniline, aniline-NHD, and aniline-ND2 were then calculated from this scaled quantum mechanical (SQM) force field and compared with experimentally observed spectra. Several corrections were made to previously proposed empirical spectral assignments. Because of computational difficulties, no definitive statement can be made about the torsion or inversion modes of the amino group. Aside from these and the C-H stretching frequencies for which the detailed assignment is still quite uncertain, the average deviation between the observed frequencies and those obtained entirely from the scaled computed force field is 9·1 cm-1. Dipole moment derivatives and infrared absorption intensities were also calculated, but these are of lower accuracy.

  2. Determination Of The Elements In The Olive Oil Responsible For The Luminescence Spectra Using A Green Laser

    NASA Astrophysics Data System (ADS)

    Fawaz, Saiof; Mahmod, Al-gafary; Lamia, Al-mamouly

    2009-09-01

    In this paper, we were able to record luminescence spectra of olive, sunflower, corn, gourd and laurel oils, chlorophyll and carotene by using an argon laser (488-514 nm) and second harmonic Nd-YAG laser (532 nm) along with a monochromator whose spectral range is 400-900 nm. Only when the luminescence light is vertical to laser light, two new peaks 540 nm and 673 nm have been detected with the latter one is more intense. In discussing our results, we succeeded in determining which materials in olive oil are responsible for producing the luminescence spectral peak; 673 nm. The experimental data has shown that the chlorophyll is the main part of the olive components which gives the olive oil luminescence spectral peak; 673 nm. The other luminescence spectral peak; 540 nm was common to all different kinds of oil in general.

  3. Spectra-selective PbS quantum dot infrared photodetectors

    NASA Astrophysics Data System (ADS)

    Qiao, Keke; Deng, Hui; Yang, Xiaokun; Dong, Dongdong; Li, Min; Hu, Long; Liu, Huan; Song, Haisheng; Tang, Jiang

    2016-03-01

    Traditional photoconductive photodetectors (PDs) commonly respond to higher energy photons compared with the bandgaps of PD active materials. Different from the wide detection spectra of traditional PDs, the present reported PbS quantum dot (QD) PDs can detect the spectra-selective light source. Spectra-selective PDs (ss-PDs) of perovskite/QDs and QD/QDs were respectively implemented by integrating two functional layers. The top layer (facing the light) was utilized to filter the non-target spectra and the bottom layer was used for detection. The response spectrum wavelength and the range of ss-PDs can be conveniently tailored by tuning the QD size. The obtained selectivity factor and normalized detectivity ratio from target and non-target illumination can reach at least 10. A narrow detection range with a full width at half maximum (FWHM) ~100 nm was applied by typical QD/QD based ss-PDs. The prototype ss-PDs were successfully applied in identifying an unknown light source. The convenient tuning and identification capabilities of the present QD based ss-PDs may provide a versatile route to obtain highly spectrum-selective PDs in order to meet the demands for special fields.

  4. Principal Component Analysis of Arctic Solar Irradiance Spectra

    NASA Technical Reports Server (NTRS)

    Rabbette, Maura; Pilewskie, Peter; Gore, Warren J. (Technical Monitor)

    2000-01-01

    During the FIRE (First ISCPP Regional Experiment) Arctic Cloud Experiment and coincident SHEBA (Surface Heat Budget of the Arctic Ocean) campaign, detailed moderate resolution solar spectral measurements were made to study the radiative energy budget of the coupled Arctic Ocean - Atmosphere system. The NASA Ames Solar Spectral Flux Radiometers (SSFRs) were deployed on the NASA ER-2 and at the SHEBA ice camp. Using the SSFRs we acquired continuous solar spectral irradiance (380-2200 nm) throughout the atmospheric column. Principal Component Analysis (PCA) was used to characterize the several tens of thousands of retrieved SSFR spectra and to determine the number of independent pieces of information that exist in the visible to near-infrared solar irradiance spectra. It was found in both the upwelling and downwelling cases that almost 100% of the spectral information (irradiance retrieved from 1820 wavelength channels) was contained in the first six extracted principal components. The majority of the variability in the Arctic downwelling solar irradiance spectra was explained by a few fundamental components including infrared absorption, scattering, water vapor and ozone. PCA analysis of the SSFR upwelling Arctic irradiance spectra successfully separated surface ice and snow reflection from overlying cloud into distinct components.

  5. Evaluation of Raman spectra of human brain tumor tissue using the learning vector quantization neural network

    NASA Astrophysics Data System (ADS)

    Liu, Tuo; Chen, Changshui; Shi, Xingzhe; Liu, Chengyong

    2016-05-01

    The Raman spectra of tissue of 20 brain tumor patients was recorded using a confocal microlaser Raman spectroscope with 785 nm excitation in vitro. A total of 133 spectra were investigated. Spectra peaks from normal white matter tissue and tumor tissue were analyzed. Algorithms, such as principal component analysis, linear discriminant analysis, and the support vector machine, are commonly used to analyze spectral data. However, in this study, we employed the learning vector quantization (LVQ) neural network, which is typically used for pattern recognition. By applying the proposed method, a normal diagnosis accuracy of 85.7% and a glioma diagnosis accuracy of 89.5% were achieved. The LVQ neural network is a recent approach to excavating Raman spectra information. Moreover, it is fast and convenient, does not require the spectra peak counterpart, and achieves a relatively high accuracy. It can be used in brain tumor prognostics and in helping to optimize the cutting margins of gliomas.

  6. Transitions and the effects of configuration interaction in the spectra of Sn XV-Sn XVIII

    NASA Astrophysics Data System (ADS)

    D'Arcy, R.; Ohashi, H.; Suda, S.; Tanuma, H.; Fujioka, S.; Nishimura, H.; Nishihara, K.; Suzuki, C.; Kato, T.; Koike, F.; White, J.; O'Sullivan, G.

    2009-04-01

    Charge state specific euv spectra from a range of tin ions have been recorded at Tokyo Metropolitan University. The spectra were produced from charge-exchange collisions between tin ions and helium atoms using an electron cyclotron resonance source. At low target gas pressures, the spectra were dominated by single capture events. The spectra were, unexpectedly, found to be dominated by an intense unresolved transition array near 13 nm while the resonance lines, including the previously identified 4p-4d S10→P11 resonance line of Sn XV, were relatively weak. From atomic structure calculations, it was found that the unresolved transition array arises from 4s24pm-14d-4s24pm-14f+4s24pm-24d2 transitions. In addition it proved necessary to include interaction with core excited 4s4pm4d configurations to fully explain the observed spectra.

  7. Adaptation of visual spectra and opsin genes in seabreams.

    PubMed

    Wang, Feng Yu; Yan, Hong Young; Chen, Johnny Shou-Chung; Wang, Tzi Yuan; Wang, Daryi

    2009-07-01

    Three species of seabreams, Acanthopagrus berda, Acanthopagrus schlegelii and Pagrus major, living at different depths, were chosen to investigate how visual spectra and opsin genes evolve in response to various photic environments. The lambda max of photoreceptors and opsin genes were measured and cloned from these species. Eight to twelve nm spectral shifts in the rod and blue cone cells were observed between the deep-sea, P. major, and shallow-sea species, A. berda and A. schlegelii. Furthermore, the deep-sea P. major has lost its red light vision. Six opsin genes, Rh1, Rh2A, Rh2B, SWS1, SWS2 and LWS, were identified from all three seabream species, with the LWS genes of P. major having undergone pseudogenization. These data indicate that the photic environment of habitats select for the physiology of visual spectra and coding of opsin genes.

  8. Comparison of 980-nm and 1070-nm in endovenous laser treatment (EVLT)

    NASA Astrophysics Data System (ADS)

    Topaloglu, Nermin; Tabakoglu, Ozgur; Ergenoglu, Mehmet U.; Gülsoy, Murat

    2009-07-01

    The use of endovenous laser treatment for varicose veins has been increasing in recent years. It is a safer technique than surgical vein stripping. Its complications (e.g. bruising, pain) are less than the complications of surgical vein stripping. But best parameters such as optimum wavelength, power, and application duration are still under investigation to clarify uncertainties about this technique. To prevent its complications and improve its clinical outcomes, the exact mechanism of it has to be known. The aim of this study is to investigate the effect of different laser wavelengths on endovenous laser therapy. In this study 980-nm diode laser and 1070-nm fiber laser were used. Human veins were irradiated with 980-nm and 1070-nm lasers at 8 W and 10 W to find the optimal power and wavelength. After laser application, remarkable shrinkage was observed. Inner and outer diameters of the veins also narrowed for both of the laser types. 10 W of 980-nm laser application led to better shrinkage results.

  9. Dual illumination OCT at 1050nm and 840nm for whole eye segment imaging

    NASA Astrophysics Data System (ADS)

    Fan, Shanhui; Qin, Lin; Dai, Cuixia; Zhou, Chuanqing

    2014-11-01

    We presented an improved dual channel dual focus spectral domain optical coherence tomography (SD-OCT) with two illuminations at 840 nm and 1050 nm for whole eye segment imaging and biometry in vivo. The two light beams were coupled and optically optimized to scan the anterior and posterior segment of the eye simultaneously. This configuration with dichroic mirrors integrated in the sample arm enables us to acquire images from the anterior segment and retina effectively with minimum loss of sample signal. In addition, the full resolved complex (FRC) method was applied to double the imaging depth for the whole anterior segment imaging by eliminating the mirror image. The axial resolution for 1050 nm and 840 nm OCT was 14 μm and 8 μm in air, respectively. Finally, the system was successfully tested in imaging the unaccommodated and accommodated eyes. The preliminary results demonstrated the significant improvements comparing with our previous dual channel SD-OCT configuration in which the two probing beams had the same central wavelength of 840 nm.

  10. TCSPC FLIM in the wavelength range from 800 nm to 1700 nm (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Becker, Wolfgang; Shcheslavsky, Vladislav

    2016-03-01

    Excitation and detection in the wavelength range above 800nm is a convenient and relatively inexpensive way to increase the penetration depth in optical microscopy. Moreover, detection at long wavelength avoids the problem that tissue autofluorescence contaminates the signals from endogenous fluorescence probes. FLIM at NIR wavelength may therefore be complementary to multiphoton microscopy, especially if the lifetimes of NIR fluorophores report biological parameters of the tissue structures they are bound to. Unfortunately, neither the excitation sources nor the detectors of standard confocal and multiphoton laser scanning systems are directly suitable for excitation and detection of NIR fluorescence. Most of these problems can be solved, however, by using ps diode lasers or Ti:Sapphire lasers at their fundamental wavelength, and NIR-sensitive detectors. With NIR-sensitive PMTs the detection wavelength range can be extended up to 900 nm, with InGaAs SPAD detectors up to 1700 nm. Here, we demonstrate the use of a combination of laser scanning, multi-dimensional TCSPC, and advanced excitation sources and detectors for FLIM at up to 1700 nm. The performance was tested at tissue samples incubated with NIR dyes. The fluorescence lifetimes generally get shorter with increasing absorption and emission wavelengths of the dyes. For the cyanine dye IR1061, absorbing around 1060 nm, the lifetime was found to be as short as 70 ps. Nevertheless the fluorescence decay could still be clearly detected. Almost all dyes showed clear lifetime changes depending on the binding to different tissue constituents.

  11. Prediction of earthquake response spectra

    USGS Publications Warehouse

    Joyner, W.B.; Boore, David M.

    1982-01-01

    We have developed empirical equations for predicting earthquake response spectra in terms of magnitude, distance, and site conditions, using a two-stage regression method similar to the one we used previously for peak horizontal acceleration and velocity. We analyzed horizontal pseudo-velocity response at 5 percent damping for 64 records of 12 shallow earthquakes in Western North America, including the recent Coyote Lake and Imperial Valley, California, earthquakes. We developed predictive equations for 12 different periods between 0.1 and 4.0 s, both for the larger of two horizontal components and for the random horizontal component. The resulting spectra show amplification at soil sites compared to rock sites for periods greater than or equal to 0.3 s, with maximum amplification exceeding a factor of 2 at 2.0 s. For periods less than 0.3 s there is slight deamplification at the soil sites. These results are generally consistent with those of several earlier studies. A particularly significant aspect of the predicted spectra is the change of shape with magnitude (confirming earlier results by McGuire and by Irifunac and Anderson). This result indicates that the conventional practice of scaling a constant spectral shape by peak acceleration will not give accurate answers. The Newmark and Hall method of spectral scaling, using both peak acceleration and peak velocity, largely avoids this error. Comparison of our spectra with the Nuclear Regulatory Commission's Regulatory Guide 1.60 spectrum anchored at the same value at 0.1 s shows that the Regulatory Guide 1.60 spectrum is exceeded at soil sites for a magnitude of 7.5 at all distances for periods greater than about 0.5 s. Comparison of our spectra for soil sites with the corresponding ATC-3 curve of lateral design force coefficient for the highest seismic zone indicates that the ATC-3 curve is exceeded within about 7 km of a magnitude 6.5 earthquake and within about 15 km of a magnitude 7.5 event. The amount by

  12. Comparison of reflectance spectra of sound and carious enamel

    NASA Astrophysics Data System (ADS)

    Analoui, Mostafa; Ando, Masatoshi; Stookey, George K.

    2000-03-01

    Development of dental caries is associated with the loss of minerals and change in the enamel structure. In this study, we have measured and compared reflectance spectra of sound and carious enamel, to investigate its utility in detection and analysis of dental caries. One hundred twenty, 3-mm diameter human enamel cores, with no sign of fluorosis, tetracycline stain, hypoplasia, fracture and restorations, were prepared. The enamel surfaces then were ground and polished. Specimens were placed on a fitted holder with either black or white color for background, with no fluorescence. The baseline spectra were measured using a spectrophotometer with enclosed diffused illumination. Spectra measured from 380 to 780 nm at 5 nm intervals. All measurements were corrected to compensate for the spectrum of illumination. The specimens were divided into two groups and exposed to a demineralizing solution, for 48 and 96 hours, respectively. Reflectance spectra of specimens were measured following lesion induction. All specimens were sectioned and analyzed by transverse microradiography (TMR), where lesion depth and mineral loss ((Delta) Z) were measured. Dimensionality of multi-spectral data was reduced through its conversion to L*a*b* color coordinates and principal component analysis (PCA). Multiple linear regression analysis showed low correlation between L*a*b* and lesion depth and mineral loss. PCA analysis showed higher correlation coefficient, compared to L*a*b*. Preliminary results of this study suggest that multi-spectral measurement and analysis of the tooth surface could be useful in predicting the depth and severity of an early carious lesion.

  13. 308-nm excimer laser in endodontics

    NASA Astrophysics Data System (ADS)

    Liesenhoff, Tim

    1992-06-01

    Root canal preparation was performed on 20 extracted human teeth. After opening the coronal pulp, the root canals were prepared by 308 nm excimer laser only. All root canals were investigated under SEM after separation in the axial direction. By sagittal separation of the mandibles of freshly slaughtered cows, it was possible to get access to the tissues and irradiate under optical control. Under irradiation of excimer laser light, tissue starts to fluoresce. It was possible to demonstrate that each tissue (dentin, enamel, bone, pulpal, and connective tissue) has a characteristic spectral pattern. The SEM analyses showed that it is well possible to prepare root canals safely. All organic soft tissue has been removed by excimer laser irradiation. There was no case of via falsa. The simultaneous spectroscopic identification of the irradiated tissue provides a safe protection from overinstrumentation. First clinical trials on 20 patients suffering of chronical apical parodontitis have been carried out successfully.

  14. 1064-nm Nd:YAG laser nucleotomy

    NASA Astrophysics Data System (ADS)

    Vari, Sandor G.; Pergadia, Vani R.; Shi, Wei-Qiang; Snyder, Wendy J.; Fishbein, Michael C.; Grundfest, Warren S.

    1993-07-01

    The high incidence of patients with clinical and neurological symptoms of lumbar disc herniation has spurred the development of less invasive and more cost efficient methods to treat patients. In this study we evaluated pulsed and continuous wave (cw) 1064 nm Nd:YAG laser ablation and induced thermal damage in sheep intervertebral disc. We used the Heraeus LaserSonics Hercules 5040 (Nd:YAG) laser system and 400 micrometers bare and 600 micrometers ball-tipped fibers in cw and pulsed mode. For the laser parameters and fibers used in this study, ablation of the intervertebral disc was successful and thermal damage did not exceed 0.5 mm. Varying beam diameters and focusing abilities (i.e., bare and ball) did not produce any difference in the coagulation thermal effect.

  15. Micromachining with femtosecond 250-nm laser pulses

    NASA Astrophysics Data System (ADS)

    Li, C.; Argument, Michael A.; Tsui, Ying Y.; Fedosejevs, Robert

    2000-12-01

    Laser micromachining is a flexible technique for precision patterning of surfaces in microelectronics, microelectromechanical devices and integrated optical devices. Typical applications include drilling of holes, cutting of conducting lines or shaping of micro component surfaces. The resolution, edge finish and residual damage to the surrounding and underlying structures depend on a variety of parameters including laser energy, intensity, pulse width and wavelength. Femtosecond pulses are of particular interest because the limited time of interaction limits the lateral expansion of the plasma and the inward propagation of the heat front. Thus, very small spot size can be achieved and minimal heating and damage of underlying layers can be obtained. An additional advantage of femtosecond pulses is that multiphoton absorption leads to efficient coupling of energy to many materials independent of the linear reflectivity of the surface. Thus metals and transmitting dielectrics, which are difficult to micromachine, may be machined with such pulses. The coupling is improved further by employing ultraviolet wavelength laser pulses where the linear absorption typically is much higher than for visible and infrared laser pulses. To explore these advantages, we have initiated a study of the interaction of 250nm femtosecond laser pulses with metals. The laser pulses are obtained by generating the third harmonic from a femtosecond Ti:sapphire laser operating at 750nm. The pulses are focused to various intensities in the range of 1010Wcm2 to 1015 Wcm2 using reflective and refractive microscope objectives and ablation thresholds and ablation rates have been determined for a few metals. In addition the ability to control feature size and produce submicron holes and lines have been investigated. The results are presented and compared to results obtained using infrared and visible femtosecond laser pulses.

  16. Optical absorption and scattering spectra of pathological stomach tissues

    NASA Astrophysics Data System (ADS)

    Giraev, K. M.; Ashurbekov, N. A.; Lakhina, M. A.

    2011-03-01

    Diffuse reflection spectra of biotissues in vivo and transmission and reflection coefficients for biotissues in vitro are measured over 300-800 nm. These data are used to determine the spectral absorption and scattering indices and the scattering anisotropy factor for stomach mucous membranes under normal and various pathological conditions (chronic atrophic and ulcerous defects, malignant neoplasms). The most importan tphysiological (hemodynamic and oxygenation levels) and structural-morphological (scatterer size and density) parameters are also determined. The results of a morphofunctional study correlate well with the optical properties and are consistent with data from a histomorphological analysis of the corresponding tissues.

  17. 1.86 W cw single-frequency 1319 nm ring laser pumped at 885 nm.

    PubMed

    Li, M L; Zhao, W F; Zhang, S B; Guo, L; Hou, W; Li, J M; Lin, X C

    2012-03-20

    A 1.86 W cw single-frequency 1319 nm laser was produced by using an 885 nm-pumped Nd:YAG crystal with a compact four-mirror ring cavity, for the first time to our knowledge. The Nd:YAG produced a slope efficiency of 21% and an optical-to-optical efficiency of 18% with respect to the absorbed diode pump power. A near-diffraction-limited beam with M(2)=1.2 was achieved under the maximum output power. PMID:22441467

  18. Measurement of 100 nm and 60 nm Particle Standards by Differential Mobility Analysis

    PubMed Central

    Mulholland, George W.; Donnelly, Michelle K.; Hagwood, Charles R.; Kukuck, Scott R.; Hackley, Vincent A.; Pui, David Y. H.

    2006-01-01

    The peak particle size and expanded uncertainties (95 % confidence interval) for two new particle calibration standards are measured as 101.8 nm ± 1.1 nm and 60.39 nm ± 0.63 nm. The particle samples are polystyrene spheres suspended in filtered, deionized water at a mass fraction of about 0.5 %. The size distribution measurements of aerosolized particles are made using a differential mobility analyzer (DMA) system calibrated using SRM® 1963 (100.7 nm polystyrene spheres). An electrospray aerosol generator was used for generating the 60 nm aerosol to almost eliminate the generation of multiply charged dimers and trimers and to minimize the effect of non-volatile contaminants increasing the particle size. The testing for the homogeneity of the samples and for the presence of multimers using dynamic light scattering is described. The use of the transfer function integral in the calibration of the DMA is shown to reduce the uncertainty in the measurement of the peak particle size compared to the approach based on the peak in the concentration vs. voltage distribution. A modified aerosol/sheath inlet, recirculating sheath flow, a high ratio of sheath flow to the aerosol flow, and accurate pressure, temperature, and voltage measurements have increased the resolution and accuracy of the measurements. A significant consideration in the uncertainty analysis was the correlation between the slip correction of the calibration particle and the measured particle. Including the correlation reduced the expanded uncertainty from approximately 1.8 % of the particle size to about 1.0 %. The effect of non-volatile contaminants in the polystyrene suspensions on the peak particle size and the uncertainty in the size is determined. The full size distributions for both the 60 nm and 100 nm spheres are tabulated and selected mean sizes including the number mean diameter and the dynamic light scattering mean diameter are computed. The use of these particles for calibrating DMAs and for

  19. The Doubling of 846 nm Light to Produce 423 nm Light for use in Atom Interferometry

    NASA Astrophysics Data System (ADS)

    Archibald, James; Birrell, Jeremey; Tang, Rebecca; Erickson, Chris; Goggins, Landon; Durfee, Dallin

    2009-10-01

    We present progress on a 423 nm fluorescence probe/cooling laser for use in our neutral calcium atom interferometer. The finished system will include an 846 nm diode laser that is coupled to a tapered amplifier. This light will be sent to a buildup cavity where we will achieve second-harmonic generation (SHG) using either a BBO non-linear crystal or a periodically-poled KTP crystal. We will discuss the theoretical considerations relating to the doubling of light in a crystal and the construction of our buildup cavity. We will also discuss its proposed application for use in atom interferometry.

  20. Absorption Measurements of Periodically Poled Potassium Titanyl Phosphate (PPKTP) at 775 nm and 1550 nm

    PubMed Central

    Steinlechner, Jessica; Ast, Stefan; Krüger, Christoph; Singh, Amrit Pal; Eberle, Tobias; Händchen, Vitus; Schnabel, Roman

    2013-01-01

    The efficient generation of second-harmonic light and squeezed light requires non-linear crystals that have low absorption at the fundamental and harmonic wavelengths. In this work the photo-thermal self-phase modulation technique is exploited to measure the absorption coefficient of periodically poled potassium titanyl phosphate (PPKTP) at 1,550 nm and 775 nm. The measurement results are (84±40) ppm/cm and (127±24) ppm/cm, respectively. We conclude that the performance of state-of-the-art frequency doubling and squeezed light generation in PPKTP is not limited by absorption. PMID:23291574

  1. 1064 nm Nd:YVO4 laser intracavity pumped at 912 nm and sum-frequency mixing for an emission at 491 nm.

    PubMed

    Herault, Emilie; Balembois, François; Georges, Patrick; Georges, Thierry

    2008-07-15

    We present for the first time a Nd:YVO(4) laser emitting at 1064 nm intracavity pumped at 912 nm by a Nd:GdVO(4) laser. We carried out a model to design the system properly, and laser performance was experimentally investigated. Intracavity sum-frequency mixing at 912 and 1064 nm was then realized in a BiBO crystal to reach the blue range. We obtained a cw output power of 155 mW at 491 nm with a pump laser diode emitting 20 W at 808 nm. PMID:18628821

  2. Medium resolution spectra of the shuttle glow in the visible region of the spectrum

    NASA Technical Reports Server (NTRS)

    Viereck, R. A.; Murad, E.; Pike, C. P.; Mende, S. B.; Swenson, G. R.; Culbertson, F. L.; Springer, B. C.

    1992-01-01

    Recent spectral measurements of the visible shuttle glow (lambda = 400 - 800 nm) at medium resolution (1 nm) reveal the same featureless continuum with a maximum near 680 nm that was reported previously. This is also in good agreement with recent laboratory experiments that attribute the glow to the emissions of NO2 formed by the recombination of O + NO. The data that are presented were taken from the aft flight deck with a hand-held spectrograph and from the shuttle bay with a low-light-level television camera. Shuttle glow images and spectra are presented and compared with laboratory data and theory.

  3. Hydrogen atom formation from the photodissociation of water ice at 193 nm.

    PubMed

    Yabushita, Akihiro; Hashikawa, Yuichi; Ikeda, Atsushi; Kawasaki, Masahiro; Tachikawa, Hiroto

    2004-03-15

    The TOF spectra of photofragment hydrogen atoms from the 193 nm photodissociation of amorphous ice at 90-140 K have been measured. The spectra consist of both a fast and a slow components that are characterized by average translational energies of 2k(B)T(trans)=0.39+/-0.04 eV (2300+/-200 K) and 0.02 eV (120+/-20 K), respectively. The incident laser power dependency of the hydrogen atom production suggests one-photon process. The electronic excitation energy of a branched cluster, (H(2)O)(6+1), has been theoretically calculated, where (H(2)O)(6+1) is a (H(2)O)(6) cyclic cluster attached by a water molecule with the hydrogen bond. The photoabsorption of this branched cluster is expected to appear at around 200 nm. The source of the hydrogen atoms is attributed to the photodissociation of the ice surface that is attached by water molecules with the hydrogen bond. Atmospheric implications are estimated for the photodissociation of the ice particles (Noctilucent clouds) at 190-230 nm in the region between 80 and 85 km altitude.

  4. Detection of methyl mercaptan with a 3393-nm distributed feedback interband cascade laser

    NASA Astrophysics Data System (ADS)

    Du, Zhenhui; Zhen, Weimeng; Zhang, Zheyuan; Li, Jinyi; Gao, Nan

    2016-04-01

    Attention has been focused recently on the harmful effects and malodor of methyl mercaptan (CH3SH), so it is desired to detect CH3SH in situ, sensitively, and selectively. We detected methyl mercaptan via tunable laser absorption spectroscopy (TLAS) with a room-temperature distributed feedback interband cascade laser emitting around 3393 nm and a hollow waveguide gas cell with 5 m length. The fundamental characteristic fingerprint absorptions of CH3SH from 3260 to 3400 nm were examined, and the spectral line 3393.584 nm (corresponding to the ν 2 C-H symmetric stretch) was determined to be the optimum for CH3SH detection. The response characteristics of the TLAS system were established by implementing a set of CH3SH concentration gradient experiments with wavelength-scanned direct absorption spectroscopy. The results show that CH3SH TLAS spectra are in excellent agreement with spectra from the Pacific Northwest National Laboratory database; the TLAS response linearity is 0.987, and the detection limit is as low as 25 ppbv (parts per billion by volume, 10-9) with integrated time 1.84 s, corresponding to an absorbance of 1.34 × 10-4 (near the theoretical detection limit). Overall, the TLAS system is a robust method for CH3SH monitoring of industrial waste gas emissions.

  5. Shifted excitation resonance Raman difference spectroscopy using a microsystem light source at 488 nm

    NASA Astrophysics Data System (ADS)

    Maiwald, M.; Sowoidnich, K.; Schmidt, H.; Sumpf, B.; Erbert, G.; Kronfeldt, H.-D.

    2010-04-01

    Experimental results in shifted excitation resonance Raman difference spectroscopy (SERRDS) at 488 nm will be presented. A novel compact diode laser system was used as excitation light source. The device is based on a distributed feedback (DFB) diode laser as a pump light source and a nonlinear frequency doubling using a periodically poled lithium niobate (PPLN) waveguide crystal. All elements including micro-optics are fixed on a micro-optical bench with a footprint of 25 mm × 5 mm. An easy temperature management of the DFB laser and the crystal was used for wavelength tuning. The second harmonic generation (SHG) provides an additional suppression of the spontaneous emission. Raman spectra of polystyrene demonstrate that no laser bandpass filter is needed for the Raman experiments. Resonance-Raman spectra of the restricted food colorant Tartrazine (FD&C Yellow 5, E 102) in distilled water excited at 488 nm demonstrate the suitability of this light source for SERRDS. A limit of detection (LOD) of 0.4 μmol.l-1 of E102 enables SERRDS at 488 nm for trace detection in e.g. food safety control as an appropriate contactless spectroscopic technique.

  6. An Inverse Modeling Approach to Estimating Phytoplankton Pigment Concentrations from Phytoplankton Absorption Spectra

    NASA Technical Reports Server (NTRS)

    Moisan, John R.; Moisan, Tiffany A. H.; Linkswiler, Matthew A.

    2011-01-01

    Phytoplankton absorption spectra and High-Performance Liquid Chromatography (HPLC) pigment observations from the Eastern U.S. and global observations from NASA's SeaBASS archive are used in a linear inverse calculation to extract pigment-specific absorption spectra. Using these pigment-specific absorption spectra to reconstruct the phytoplankton absorption spectra results in high correlations at all visible wavelengths (r(sup 2) from 0.83 to 0.98), and linear regressions (slopes ranging from 0.8 to 1.1). Higher correlations (r(sup 2) from 0.75 to 1.00) are obtained in the visible portion of the spectra when the total phytoplankton absorption spectra are unpackaged by multiplying the entire spectra by a factor that sets the total absorption at 675 nm to that expected from absorption spectra reconstruction using measured pigment concentrations and laboratory-derived pigment-specific absorption spectra. The derived pigment-specific absorption spectra were further used with the total phytoplankton absorption spectra in a second linear inverse calculation to estimate the various phytoplankton HPLC pigments. A comparison between the estimated and measured pigment concentrations for the 18 pigment fields showed good correlations (r(sup 2) greater than 0.5) for 7 pigments and very good correlations (r(sup 2) greater than 0.7) for chlorophyll a and fucoxanthin. Higher correlations result when the analysis is carried out at more local geographic scales. The ability to estimate phytoplankton pigments using pigment-specific absorption spectra is critical for using hyperspectral inverse models to retrieve phytoplankton pigment concentrations and other Inherent Optical Properties (IOPs) from passive remote sensing observations.

  7. Classification and radiative-transfer modeling of meteorite spectra

    NASA Astrophysics Data System (ADS)

    Pentikäinen, H.; Penttilä, A.; Peltoniemi, J.; Muinonen, K.

    2014-07-01

    The interpretation of asteroid spectra is closely tied to surface structure and composition. Asteroid surfaces are usually assumed to be covered with a regolith, which is a mixture of mineral grains ranging from micrometers to centimeters in size. The inverse problem of deducing the characteristics of the grains from the scattering of light (e.g., using photometric and polarimetric observations) is difficult. Meteorite spectroscopy can be a valuable alternative source of information considering that unweathered meteoritic ''falls'' are almost pristine samples of their parent bodies. Reflectance spectra of 18 different meteorite samples were measured with the Finnish Geodetic Institute Field Goniospectrometer (FIGIFIGO) covering a wavelength range of 450--2250 nm [1,2]. The measurements expand the database of reflectance spectra obtained by Paton et al. [3] and Gaffey [4]. Principal Component Analysis (PCA) performed on the spectra indicates a separation of the undifferentiated ordinary chondrites and the differentiated achondrites. The principal components also suggest a discrimination between the spectra of ordinary chondrites with petrologic grades 5 and 6. The distinction is not present when the data are supplemented with the spectra from the two other data sets obtained with differing measuring techniques. To further investigate the different classifications, the PCA is implemented with selected spectral features contrary to the previous analyses, which encompassed the complete spectra. Single-scattering albedos for meteoritic fundamental scatterers were derived with a Monte Carlo radiative-transfer model [1]. In the derivation, realistic scattering phase functions were utilized. The functions were obtained by fitting triple Henyey-Greenstein functions to the measured scattering phase functions of olivine powder for two different size distributions [5,6]. The simulated reflectances for different scattering phase functions were matched to the measured meteorite

  8. Action spectra for photosynthetic inhibition

    NASA Technical Reports Server (NTRS)

    Caldwell, M. M.; Flint, S.; Camp, L. B.

    1981-01-01

    The ultraviolet action spectrum for photosynthesis inhibition was determined to fall between that of the general DNA action spectrum and the generalized plant action spectrum. The characteristics of this action spectrum suggest that a combination of pronounced increase in effectiveness with decreasing wavelength, substantial specificity for the UV-B waveband, and very diminished response in the UV-A waveband result in large radiation amplification factors when the action spectra are used as weighting functions. Attempted determination of dose/response relationships for leaf disc inhibition provided inconclusive data from which to deconvolute an action spectrum.

  9. DUO: Spectra of diatomic molecules

    NASA Astrophysics Data System (ADS)

    Yurchenko, Sergei N.; Lodi, Lorenzo; Tennyson, Jonathan; Stolyarov, Andrey V.

    2016-05-01

    Duo computes rotational, rovibrational and rovibronic spectra of diatomic molecules. The software, written in Fortran 2003, solves the Schrödinger equation for the motion of the nuclei for the simple case of uncoupled, isolated electronic states and also for the general case of an arbitrary number and type of couplings between electronic states. Possible couplings include spin-orbit, angular momenta, spin-rotational and spin-spin. Introducing the relevant couplings using so-called Born-Oppenheimer breakdown curves can correct non-adiabatic effects.

  10. DUO: Spectra of diatomic molecules

    NASA Astrophysics Data System (ADS)

    Yurchenko, Sergei N.; Lodi, Lorenzo; Tennyson, Jonathan; Stolyarov, Andrey V.

    2016-05-01

    Duo computes rotational, rovibrational and rovibronic spectra of diatomic molecules. The software, written in Fortran 2003, solves the Schrödinger equation for the motion of the nuclei for the simple case of uncoupled, isolated electronic states and also for the general case of an arbitrary number and type of couplings between electronic states. Possible couplings include spin–orbit, angular momenta, spin-rotational and spin–spin. Introducing the relevant couplings using so-called Born–Oppenheimer breakdown curves can correct non-adiabatic effects.

  11. Gamma-ray burst spectra

    NASA Technical Reports Server (NTRS)

    Teegarden, B. J.

    1982-01-01

    A review of recent results in gamma-ray burst spectroscopy is given. Particular attention is paid to the recent discovery of emission and absorption features in the burst spectra. These lines represent the strongest evidence to date that gamma-ray bursts originate on or near neutron stars. Line parameters give information on the temperature, magnetic field and possibly the gravitational potential of the neutron star. The behavior of the continuum spectrum is also discussed. A remarkably good fit to nearly all bursts is obtained with a thermal-bremsstrahlung-like continuum. Significant evolution is observed of both the continuum and line features within most events.

  12. Comparative study of reflectance spectra for human Laogong acupoint and non-acupoint tissues irradiated by laser

    NASA Astrophysics Data System (ADS)

    Zhang, Zude; Guo, Zhouyi; Wei, Huajiang; Zhong, Huiqing; Yang, Hongqin; Xie, Shusen; Liu, Songhao

    2008-12-01

    Reflection spectra of human Laogong acupoint (PC8) and non-acupoint tissue which irradiated by different power were studied in the spectral range from 400 nm to 1000 nm in vivo. A wavelength of 808 nm semiconductor laser was used for irradiation at the power of 0 mw (empty irradiation), 20 mw, 50 mw and 100 mw for ten minutes. Reflection spectra were measured with an AvaSpec-2048 optical fiber spectroscopy with an integrating sphere attachment. The result shows that when empty irradiated, the shape of the reflectance spectra of Laogong acupoint and non-acupoint are similar, they have the same troughs at 423 nm, 544 nm, 577 nm and 980 nm, the reflectance at these wavelengths for Laogong acupoint are 17.1%, 26.1%, 25.9%, 35.0%, and for non-acupoint are 17.1%, 27.6%, 28.1%, 36.5%. But from 475 nm to 1000 nm, the reflectance of Laogong acupoint is smaller than that of non-acoupoint. After irradiated by laser at the power of 20 mw, 50 mw, and 100 mw, there is a very significant decrease in the reflectance spectra of Laogong acupoint comparing to that of empty irradiated, and the higher power, the lower reflectance. But there is just a small decrease in the reflectance spectra of non-acupoint comparing to that of empty irradiated. From the above results, it is clearly to see that Laogong acupoint is more sensitive than non-acupoint when irradiated by semiconductor laser.

  13. Photodissociation of the Propargyl (C3D3) Radicals at 248 nm and 193 nm

    SciTech Connect

    Neumark., D.M.; Crider, P.E.; Castiglioni, L.; Kautzman, K.K.

    2009-01-21

    The photodissociation of perdeuterated propargyl (D{sub 2}CCCD) and propynyl (D{sub 3}CCC) radicals was investigated using fast beam photofragment translational spectroscopy. Radicals were produced from their respective anions by photodetachment at 540 nm and 450 nm (below and above the electron affinity of propynyl). The radicals were then photodissociated by 248 nm or 193 nm light. The recoiling photofragments were detected in coincidence with a time- and position-sensitive detector. Three channels were observed: D{sub 2} loss, CD + C{sub 2}D{sub 2}, and CD{sub 3} + C{sub 2}. Obervation of the D loss channel was incompatible with this experiment and was not attempted. Our translational energy distributions for D{sub 2} loss peaked at nonzero translational energy, consistent with ground state dissociation over small (< 1 eV) exit barriers with respect to separated products. Translational energy distributions for the two heavy channels peaked near zero kinetic energy, indicating dissociation on the ground state in the absence of exit barriers.

  14. Evaluation of the Diode laser (810nm,980nm) on dentin tubule diameter following internal bleaching

    PubMed Central

    Kiomarsi, Nazanin; Salim, Soheil; Sarraf, Pegah; Javad-Kharazifard, Mohammad

    2016-01-01

    Background The aim of this study was to evaluate the effect of diode laser irradiation and bleaching materials on the dentinal tubule diameter after laser bleaching. Material and Methods The dentin discs of 40 extracted third molar were used in this experiment. Each disc surface was divided into two halves by grooving. Half of samples were laser bleached at different wavelengths with two different concentrations of hydrogen peroxide. Other half of each disc with no laser bleaching remained as a negative control. Dentin discs were assigned randomly into four groups (n=10) with following hydrogen peroxide and diode laser wavelength specifications; Group 1 (30% - 810 nm), group 2 (30% - 980 nm), group 3 (46% - 810 nm) and group 4 (46% - 980 nm). All specimens were sent for scanning electron microscopic (SEM) analysis in order to measure tubular diameter in laser treated and control halves. Data were analyzed by ANOVA and Tukey test (p<0.05). Results A significant reduction in dentin tubule diameter was observed in groups 1, 2 and 4. There was no significant difference between groups 1 and 2 and between groups 3 and 4 after bleaching. Conclusions The SEM results showed that diode laser was able to reduce dentin tubule diameter and its effect on dentin was dependent on chemical action of bleaching material. Key words:Laser, diode, dentin, tubule, diameter. PMID:27398172

  15. NXT:1980Di immersion scanner for 7nm and 5nm production nodes

    NASA Astrophysics Data System (ADS)

    de Graaf, Roelof; Weichselbaum, Stefan; Droste, Richard; McLaren, Matthew; Koek, Bert; de Boeij, Wim

    2016-03-01

    Immersion scanners remain the critical lithography workhorses in semiconductor device manufacturing. When progressing towards the 7nm device node for logic and D18 device node for DRAM production, pattern-placement and layer-to-layer overlay requirements keep progressively scaling down and consequently require system improvements in immersion scanners. The on-product-overlay requirements are approaching levels of only a few nanometers, imposing stringent requirements on the scanner tool design in terms of reproducibility, accuracy and stability. In this paper we report on the performance of the NXT:1980Di immersion scanner. The NXT:1980Di builds upon the NXT:1970Ci, that is widely used for 16nm, 14nm and 10nm high-volume manufacturing. We will discuss the NXT:1980Di system- and sub-system/module enhancements that drive the scanner overlay, focus and productivity performance. Overlay, imaging, focus, productivity and defectivity data will be presented for multiple tools. To further reduce the on-product overlay system performance, alignment sensor contrast improvements as well as active reticle temperature conditioning are implemented on the NXT:1980Di. Reticle temperature conditioning will reduce reticle heating overlay and the higher contrast alignment sensor will improve alignment robustness for processed alignment targets. Due to an increased usage of multiple patterning techniques, an increased number of immersion exposures is required. NXT:1980Di scanner design modifications raised productivity levels from 250wph to 275wph. This productivity enhancement provides lower cost of ownership (CoO) for customers using immersion technology.

  16. THE SPECTRUM OF THORIUM FROM 250 nm TO 5500 nm: RITZ WAVELENGTHS AND OPTIMIZED ENERGY LEVELS

    SciTech Connect

    Redman, Stephen L.; Nave, Gillian; Sansonetti, Craig J.

    2014-03-01

    We have made precise observations of a thorium-argon hollow cathode lamp emission spectrum in the region between 350 nm and 1175 nm using a high-resolution Fourier transform spectrometer. Our measurements are combined with results from seven previously published thorium line lists to re-optimize the energy levels of neutral, singly, and doubly ionized thorium (Th I, Th II, and Th III). Using the optimized level values, we calculate accurate Ritz wavelengths for 19, 874 thorium lines between 250 nm and 5500 nm (40, 000 cm{sup –1} to 1800 cm{sup –1}). We have also found 102 new thorium energy levels. A systematic analysis of previous measurements in light of our new results allows us to identify and propose corrections for systematic errors in Palmer and Engleman and typographical errors and incorrect classifications in Kerber et al. We also found a large scatter with respect to the thorium line list of Lovis and Pepe. We anticipate that our Ritz wavelengths will lead to improved measurement accuracy for current and future spectrographs that make use of thorium-argon or thorium-neon lamps as calibration standards.

  17. THE 217.5 nm BAND, INFRARED ABSORPTION, AND INFRARED EMISSION FEATURES IN HYDROGENATED AMORPHOUS CARBON NANOPARTICLES

    SciTech Connect

    Duley, W. W.; Hu, Anming E-mail: a2hu@uwaterloo.ca

    2012-12-20

    We report on the preparation of hydrogenated amorphous carbon nanoparticles whose spectral characteristics include an absorption band at 217.5 nm with the profile and characteristics of the interstellar 217.5 nm feature. Vibrational spectra of these particles also contain the features commonly observed in absorption and emission from dust in the diffuse interstellar medium. These materials are produced under ''slow'' deposition conditions by minimizing the flux of incident carbon atoms and by reducing surface mobility. The initial chemistry leads to the formation of carbon chains, together with a limited range of small aromatic ring molecules, and eventually results in carbon nanoparticles having an sp {sup 2}/sp {sup 3} ratio Almost-Equal-To 0.4. Spectroscopic analysis of particle composition indicates that naphthalene and naphthalene derivatives are important constituents of this material. We suggest that carbon nanoparticles with similar composition are responsible for the appearance of the interstellar 217.5 nm band and outline how these particles can form in situ under diffuse cloud conditions by deposition of carbon on the surface of silicate grains. Spectral data from carbon nanoparticles formed under these conditions accurately reproduce IR emission spectra from a number of Galactic sources. We provide the first detailed fits to observational spectra of Type A and B emission sources based entirely on measured spectra of a carbonaceous material that can be produced in the laboratory.

  18. Faster qualification of 193-nm resists for 100-nm development using photo cell monitoring

    NASA Astrophysics Data System (ADS)

    Jones, Chris M.; Kallingal, Chidam; Zawadzki, Mary T.; Jeewakhan, Nazneen N.; Kaviani, Nazila N.; Krishnan, Prakash; Klaum, Arthur D.; Van Ess, Joel

    2003-05-01

    The development of 100-nm design rule technologies is currently taking place in many R&D facilities across the world. For some critical alyers, the transition to 193-nm resist technology has been required to meet this leading edge design rule. As with previous technology node transitions, the materials and processes available are undergoing changes and improvements as vendors encounter and solve problems. The initial implementation of the 193-nm resits process did not meet the photolithography requirements of some IC manufacturers due to very high Post Exposure Bake temperature sensitivity and consequently high wafer to wafer CD variation. The photoresist vendors have been working to improve the performance of the 193-nm resists to meet their customer's requirements. Characterization of these new resists needs to be carried out prior to implementation in the R&D line. Initial results on the second-generation resists evaluated at Cypress Semicondcutor showed better CD control compared to the aelrier resist with comparable Depth of Focus (DOF), Exposure Latitute, Etch Resistance, etc. In addition to the standard lithography parameters, resist characterization needs to include defect density studies. It was found that the new resists process with the best CD control, resulted in the introduction of orders of magnitude higher yield limiting defects at Gate, Contact adn Local Interconnect. The defect data were shared with the resists vendor and within days of the discovery the resist vendor was able to pinpoint the source of the problem. The fix was confirmed and the new resists were successfully released to production. By including defect monitoring into the resist qualification process, Cypress Semiconductor was able to 1) drive correction actions earlier resulting in faster ramp and 2) eliminate potential yield loss. We will discuss in this paper how to apply the Micro Photo Cell Monitoring methodology for defect monitoring in the photolithogprhay module and the

  19. 34 nm Charge Transport through DNA

    NASA Astrophysics Data System (ADS)

    Slinker, Jason; Muren, Natalie; Renfrew, Sara; Barton, Jacqueline

    2011-03-01

    Long-range charge transport through DNA has broad-reaching implications due to its inherent biological recognition capabilities and unmatched capacity to be patterned into precise, nanoscale shapes. We have observed charge transport through 34 nm DNA monolayers (100 base pairs) using DNA-mediated electrochemistry. Cyclic voltammetry of multiplexed gold electrodes modified with 100mer DNAs reveal sizable peaks from distally-bound Nile Blue redox probes for well matched duplexes but highly attenuated redox peaks from 100mer monolayers containing a single base pair mismatch, demonstrating that the charge transfer is DNA-mediated. The 100mers on the gold surface are efficiently cleaved by the restriction enzyme RsaI. The 100mers in the DNA film thus adopt conformations that are readily accessible to protein binding and restriction. The ability to assemble well-characterized DNA films with these 100mers permits the demonstration of charge transport over distances surpassing most reports of molecular wires. Supported by funding from the NIH/NIBIB.

  20. Illumination optimization for 65nm technology node

    NASA Astrophysics Data System (ADS)

    Wang, Ching-Heng; Liu, Qingwei; Zhang, Liguo; Hung, Chi-Yuan

    2006-10-01

    The most important task of the microlithography process is to make the manufacturable process latitude/window, including dose latitude and Depth of Focus, as wide as possible. Thus, to perform a thorough source optimization during process development is becoming more critical as moving to high NA technology nodes. Furthermore, Optical proximity correction (OPC) are always used to provide a common process window for structures that would, otherwise, have no overlapping windows. But as the critical dimension of the IC design shrinks dramatically, the flexibility for applying OPC also decreases. So a robust microlithography process should also be OPC-friendly. This paper demonstrates our work on the illumination optimization during the process development. The Calibre ILO (Illumination Optimization) tool was used to perform the illumination optimization and provided plots of DOF vs. various parametric illumination settings. This was used to screen the various illumination settings for the one with optimum process margins. The resulting illumination conditions were then implemented and analyzed at a real wafer level on our 90/65nm critical layers, such as Active, Poly, Contact and Metal. In conclusion, based on these results, a summary is provided highlighting how OPC can get benefit from proper illumination optimization.

  1. Modification of luminescence spectra of CaF2:Eu2+.

    PubMed

    Singh, Vartika S; Joshi, C P; Moharil, S V; Muthal, P L; Dhopte, S M

    2015-11-01

    CaF2:Eu(2+) is a well known phosphor having efficient excitation in the near ultraviolet (NUV) range. Phosphors with NUV excitation are required in newly emerging applications such as photoluminescence liquid crystal displays (PLLCD), solid-state lighting (SSL), and down-conversion for solar cells. However, emission of CaF2:Eu(2+) is around 424 nm. Eye sensitivity drops considerably at these wavelengths. It is thus not useful for display applications for which emission in one of the primary colours (blue - 450 nm, green - 540 nm or red - 610 nm) is required. Efforts were made to modify the Photoluminescence (PL) spectra of CaF2:Eu(2+) to meet these requirements using co-dopants. A Ca0.49 Sr0.50 Eu0.01 F2 phosphor showing better colour coordinates and having an emission maximum around 440 nm was discovered during these studies.

  2. All-weather ultraviolet solar spectra retrieved at a 0.5-Hz sampling rate.

    PubMed

    Thorseth, T M; Kjeldstad, B

    1999-10-20

    A measurement scheme and an algorithm have been developed to retrieve global irradiance ultraviolet solar spectra (290-400 nm) at a sampling rate of 0.5 Hz. The algorithm combines spectral irradiance measurements performed with a slow (a few minutes) scanning spectroradiometer (Optronic Model OL752) and a moderate bandwidth multichannel radiometer (Biospherical ground-based ultraviolet radiometer Model 541). The filter radiometer instrument allows for continuous observations of global UV radiation at five channels (approximately 10-nm bandwidth), performed simultaneously with spectral measurements. Information about changing cloud conditions during a spectral scan was retrieved from filter measurements and applied to spectral data, hence estimated spectra without cloud variations could be constructed. The quality of the estimated spectra depends on data quality from both instruments. The method works well in all kinds of weather conditions, as long as the Sun is above the horizon and none of the instruments are hampered by measurement errors. PMID:18324148

  3. Selection of Portable Spectrometers for Planetary Exploration: A Comparison of 532 nm and 785 nm Raman Spectroscopy of Reduced Carbon in Archean Cherts

    PubMed Central

    Hutchinson, Ian B.; Ingley, Richard; Marshall, Craig P.; Olcott Marshall, Alison; Edwards, Howell G.M.

    2015-01-01

    Abstract Knowledge and understanding of the martian environment has advanced greatly over the past two decades, beginning with NASA's return to the surface of Mars with the Pathfinder mission and its rover Sojourner in 1997 and continuing today with data being returned by the Curiosity rover. Reduced carbon, however, is yet to be detected on the martian surface, despite its abundance in meteorites originating from the planet. If carbon is detected on Mars, it could be a remnant of extinct life, although an abiotic source is much more likely. If the latter is the case, environmental carbonaceous material would still provide a source of carbon that could be utilized by microbial life for biochemical synthesis and could therefore act as a marker for potential habitats, indicating regions that should be investigated further. For this reason, the detection and characterization of reduced or organic carbon is a top priority for both the ESA/Roscosmos ExoMars rover, currently due for launch in 2018, and for NASA's Mars 2020 mission. Here, we present a Raman spectroscopic study of Archean chert Mars analog samples from the Pilbara Craton, Western Australia. Raman spectra were acquired with a flight-representative 532 nm instrument and a 785 nm instrument with similar operating parameters. Reduced carbon was successfully detected with both instruments; however, its Raman bands were detected more readily with 785 nm excitation, and the corresponding spectra exhibited superior signal-to-noise ratios and reduced background levels. Key Words: Raman spectroscopy—Archean—Organic matter—Planetary science—Mars. Astrobiology 15, 420–429. PMID:26060980

  4. Creation and testing of an artificial neural network based carbonate detector for Mars rovers

    NASA Technical Reports Server (NTRS)

    Bornstein, Benjamin; Castano, Rebecca; Gilmore, Martha S.; Merrill, Matthew; Greenwood, James P.

    2005-01-01

    We have developed an artificial neural network (ANN) based carbonate detector capable of running on current and future rover hardware. The detector can identify calcite in visible/NIR (350-2500 nm) spectra of both laboratory specimens covered by ferric dust and rocks in Mars analogue field environments. The ANN was trained using the Backpropagation algorithm with sigmoid activation neurons. For the training dataset, we chose nine carbonate and eight non-carbonate representative mineral spectra from the USGS spectral library. Using these spectra as seeds, we generated 10,000 variants with up to 2% Gaussian noise in each reflectance measurement. We cross-validated several ANN architectures, training on 9,900 spectra and testing on the remaining 100. The best performing ANN correctly detected, with perfect accuracy, the presence (or absence) of carbonate in spectral data taken on field samples from the Mojave desert and clean, pure marbles from CT. Sensitivity experiments with JSC Mars-1 simulant dust suggest the carbonate detector would perform well in aeolian Martian environments.

  5. Photodissociation of ozone at 276nm by photofragment imaging and high resolution photofragment translational spectroscopy

    SciTech Connect

    Blunt, D.A.; Suits, A.G.

    1996-11-01

    The photodissociation of ozone at 276 nm is investigated using both state resolved ion imaging and high-resolution photofragment translational spectroscopy. Ion images from both [3+1] and [2+1] resonance enhanced multiphoton ionization of the O({sup 1}D) photofragment are reported. All images show strong evidence of O({sup 1}D) orbital alignment. Photofragment translation spectroscopy time-of-flight spectra are reported for the O{sub 2} ({sup 1}{Delta}{sub g}) photofragment. Total kinetic energy release distributions determined form these spectra are generally consistent with those distributions determined from imaging data. Observed angular distributions are reported for both detection methods, pointing to some unresolved questions for ozone dissociation in this wavelength region.

  6. Optical properties of apple skin and flesh in the wavelength range from 350 to 2200 nm

    NASA Astrophysics Data System (ADS)

    Saeys, Wouter; Velazco-Roa, Maria A.; Thennadil, Suresh N.; Ramon, Herman; Nicolaï, Bart M.

    2008-03-01

    Optical measurement of fruit quality is challenging due to the presence of a skin around the fruit flesh and the multiple scattering by the structured tissues. To gain insight in the light-tissue interaction, the optical properties of apple skin and flesh tissue are estimated in the 350-2200 nm range for three cultivars. For this purpose, single integrating sphere measurements are combined with inverse adding-doubling. The observed absorption coefficient spectra are dominated by water in the near infrared and by pigments and chlorophyll in the visible region, whose concentrations are much higher in skin tissue. The scattering coefficient spectra show the monotonic decrease with increasing wavelength typical for biological tissues with skin tissue being approximately three times more scattering than flesh tissue. Comparison to the values from time-resolved spectroscopy reported in literature showed comparable profiles for the optical properties, but overestimation of the absorption coefficient values, due to light losses.

  7. Self-frequency-doubled BaTeMo2O9 Raman laser emitting at 589 nm.

    PubMed

    Gao, Z L; Liu, S D; Zhang, J J; Zhang, S J; Zhang, W G; He, J L; Tao, X T

    2013-03-25

    In this paper, the spontaneous Raman spectra and second harmonic generation (SHG) properties at 589 nm of a novel Raman crystal BaTeMo(2)O(9) (BTM) were investigated. The BTM crystal was cut along the type-II SHG phase-matching direction for the first-order Raman shift at 1178 nm to realize the SRS and SHG simultaneously. Pumped by a nanosecond 1064 nm laser source, a self-frequency-doubled BTM Raman laser operating at 589 nm has been demonstrated for the first time. At the pump pulse energy of 48 mJ, the maximum yellow laser output pulse energy of 5.6 mJ was obtained with an optical-to-optical conversion efficiency of 11.7%. Our results show that BTM crystal is one of the promising candidate Raman materials to generate yellow laser radiation.

  8. Spectral emission properties of a LPP light source in the sub-200nm range for wafer inspection applications

    NASA Astrophysics Data System (ADS)

    Gambino, Nadia; Rollinger, Bob; Hudgins, Duane; Abhari, Reza; Abreau, F.

    2015-03-01

    In this work, the spectral emission proprieties of a droplet-based laser-produced plasma are investigated in the VUV range. These studies are performed with a spectrograph operating from 30 nm to 180 nm at a spectral resolution of 0.1 nm. The emission spectra are recorded for different droplet-based metal fuels such as tin, indium and gallium in the presence of different background gas pressure levels. The experimental results are relevant for alternative light sources that would be needed for future wafer inspection tools. In addition, the experimental results help to determine the Out- Of-Band (OOB) radiation emission of the EUV source. By tuning the type of fuel, the laser energies and the background gas, the LPP light source shows good capabilities to be operated as a tunable light source that covers a spectral emission range from the EUV to the sub-200 nm range.

  9. [Instantaneous emission spectra of epoxypropane in the process of deflagration to detonation transition].

    PubMed

    Li, Ping; Yuan, Chang-ying; Hu, Dong; Liu, Jun-chao; Zhu-mei, Sun; Dong, Shi; Xiao, Hai-bo

    2004-07-01

    Using an intensified CCD spectroscopic detector (Princeton Instruments, ICCD PI-Max 1024 RB) which can be gated in as little as 5 ns, the synchronization of the measuring system was controlled by a digital delay generator (Stanford Research Systems, DG535), the DG535 was triggered externally by a lab-made electrical pulse generator which transformed the optical trigger signal to an electrical signal, and the light signal from the end window of an explosion shock tube was delivered by an 1 mm in diameter plastic optical fiber to the entrance slit of the spectrometer (grating of 150 g x mm(-1) , central wavelength of 550 nm). The spectrum measurement of the epoxypropane in the process of deflagration to detonation transition (DDT) was then made. The instantaneous emission spectra of epoxypropane at different time of the DDT process with an exposure time of several microseconds were acquired. Results show that at the beginning of the DDT process, the emitted light was very weak and the line spectra of atoms were observed mainly; in the middle process of the DDT, the emitted light became strong and the spectra observed consisted of line spectra of atoms, band spectra of molecules plus continuous spectrum of the thermal radiation; when the detonation was formed, the emitted light got very strong, and the spectra acquired consisted of both line spectra of atoms and band spectra of molecules superimposed on the strong continuum of the thermal radiation. PMID:15766070

  10. [Instantaneous emission spectra of epoxypropane in the process of deflagration to detonation transition].

    PubMed

    Li, Ping; Yuan, Chang-ying; Hu, Dong; Liu, Jun-chao; Zhu-mei, Sun; Dong, Shi; Xiao, Hai-bo

    2004-07-01

    Using an intensified CCD spectroscopic detector (Princeton Instruments, ICCD PI-Max 1024 RB) which can be gated in as little as 5 ns, the synchronization of the measuring system was controlled by a digital delay generator (Stanford Research Systems, DG535), the DG535 was triggered externally by a lab-made electrical pulse generator which transformed the optical trigger signal to an electrical signal, and the light signal from the end window of an explosion shock tube was delivered by an 1 mm in diameter plastic optical fiber to the entrance slit of the spectrometer (grating of 150 g x mm(-1) , central wavelength of 550 nm). The spectrum measurement of the epoxypropane in the process of deflagration to detonation transition (DDT) was then made. The instantaneous emission spectra of epoxypropane at different time of the DDT process with an exposure time of several microseconds were acquired. Results show that at the beginning of the DDT process, the emitted light was very weak and the line spectra of atoms were observed mainly; in the middle process of the DDT, the emitted light became strong and the spectra observed consisted of line spectra of atoms, band spectra of molecules plus continuous spectrum of the thermal radiation; when the detonation was formed, the emitted light got very strong, and the spectra acquired consisted of both line spectra of atoms and band spectra of molecules superimposed on the strong continuum of the thermal radiation.

  11. OPC structures for maskshops qualification for the CMOS65nm and CMOS45nm nodes

    NASA Astrophysics Data System (ADS)

    Sundermann, Frank; Trouiller, Yorick; Urbani, Jean-Christophe; Couderc, Christophe; Belledent, Jérôme; Borjon, Amandine; Foussadier, Franck; Gardin, Christian; LeCam, Laurent; Rody, Yves; Saied, Mazen; Yesilada, Emek; Martinelli, Catherine; Wilkinson, Bill; Vautrin, Florent; Morgana, Nicolo; Robert, Frederic; Montgomery, Patrick; Kerrien, Gurwan; Planchot, Jonathan; Farys, Vincent; Di Maria, Jean-Luc

    2007-02-01

    Several qualification stages are required for new maskshop tools, first step is done by the maskshop internally. Taking a new writer for example, the maskshop will review the basic factory and site acceptance tests, including CD uniformity, CD linearity, local CD errors and registration errors. The second step is to have dedicated OPC (Optical Proximity Correction) structures from the wafer fab. These dedicated OPC structures will be measured by the maskshop to get a reticle CD metrology trend line. With this trend line, we can: - ensure the stability at reticle level of the maskshop processes - put in place a matching procedure to guarantee the same OPC signature at reticle level in case of any internal maskshop process change or new maskshop evaluation. Changes that require qualification could be process changes for capacity reasons, like introducing a new writer or a new manufacturing line, or for capability reasons, like a new process (new developer tool for example) introduction. Most advanced levels will have dedicated OPC structures. Also dedicated maskshop processes will be monitored with these specific OPC structures. In this paper, we will follow in detail the different reticle CD measurements of dedicated OPC structures for the three advanced logic levels of the 65nm node: poly level, contact level and metal level. The related maskshop's processes are - for poly: eaPSM 193nm with a nega CAR (Chemically Amplified Resist) process for Clear Field L/S (Lines & Space) reticles - for contact: eaPSM 193nm with a posi CAR process for Dark Field Holes reticles - for metal1: eaPSM 193nm with a posi CAR process for Dark Field L/S reticles. For all these structures, CD linearity, CD through pitch, length effects, and pattern density effects will be monitored. To average the metrology errors, the structures are placed twice on the reticle. The first part of this paper will describe the different OPC structures. These OPC structures are close to the DRM (Design Rule

  12. An RGB approach to extraordinary spectra

    NASA Astrophysics Data System (ADS)

    Grusche, Sascha; Theilmann, Florian

    2015-09-01

    After Newton had explained a series of ordinary spectra and Goethe had pointed out its complementary counterpart, Nussbaumer discovered a series of extraordinary spectra which are geometrically identical and colourwise analogous to Newton’s and Goethe’s spectra. To understand the geometry and colours of extraordinary spectra, the wavelength composition is explored with filters and spectroscopic setups. Visualized in a dispersion diagram, the wavelength composition is interpreted in terms of additive colour mixing. Finally, all spectra are simulated as the superposition of red, green, and blue images that are shifted apart. This RGB approach makes it easy to understand the complex relationship between wavelengths and colours.

  13. Effects of organic moieties on the photoluminescence spectra of perovskite-type tin bromide based compounds

    NASA Astrophysics Data System (ADS)

    Papavassiliou, George C.; Vidali, Maria-Sofia; Pagona, Georgia; Mousdis, George A.; Karousis, Nikolaos; Koutselas, Ioannis

    2015-04-01

    The photoluminescence (PL) and optical absorption (OA) spectra of some compounds of the type (SC)SnBr3, (BC)2SnBr4, and (SC)(BC)2Sn2Br7 (where SC is CH3NH3 + or Cs+; BC is C4H9NH3 + ,CH3C6H4CH2NH3 + ,C12H25NH3 + ,C18H37NH3 + and 1-naphthylmethyl ammonium group), in the forms of thin deposits on several substrates, are investigated. Generally, using the 350 nm as excitation line, the obtained PL spectra of compounds of the type (BC)2SnBr4 with short alkyl chain-length in the alkyl ammonium moiety, show broad and strong bands. For example, the PL spectra of compound (C4H9NH3)2SnBr4 exhibit a weak band at ca 475 nm, attributed to free-excitons and a broad and strong band at ca 570 nm, attributed to radiative decay of self-trapped excitons in the inorganic moiety. This is a bright yellow-orange emission, which can be seen by naked eye, even at room temperature. In the case of the compounds with long alkyl chain-length in the alkyl ammonium moiety, the PL spectra are dominated by an excitonic band, which occurs close to the corresponding fundamental OA edge. The PL spectrum of (1-naphthylmethyl ammonium)2SnBr4 shows the strong red band with main maxima at ca 603 and 642 nm, arising from tetramers of naphthyl moieties. Also, the PL spectra of the compounds of the type (SC)SnBr3 and (SC)(BC)2Sn2Br7, after grinding, show strong bands at 600-620 nm.

  14. Brane Constructions and BPS Spectra

    NASA Astrophysics Data System (ADS)

    Rastogi, Ashwin

    The object of this work is to exploit various constructions of string theory and M-theory to yield new insights into supersymmetric theories in both four and three dimensions. In 4d, we extend work on Seiberg-Witten theory to study and compute BPS spectra of the class of complete N = 2 theories. The approach we take is based on the program of geometric engineering, in which 4d theories are constructed from compactifications of type IIB strings on Calabi-Yau manifolds. In this setup, the natural candidates for BPS states are D3 branes wrapped on supersymmetric 3-cycles in the Calabi-Yau. Our study makes use of the mathematical structure of quivers, whose representation theory encodes the notion of stability of BPS particles. Except for 11 exceptional cases, all complete theories can be constructed by wrapping stacks of two M5 branes on Riemann surfaces. By exploring the connection between quivers and M5 brane theories, we develop a powerful algorithm for computing BPS spectra, and give an in-depth study of its applications. In particular, we compute BPS spectra for all asymptotically free complete theories, as well as an infinite set of conformal SU(2)k theories with certain matter content. From here, we go on to apply the insight gained from our 4d study to 3d gauge theories. We consider the analog of the M5 brane construction in the case of 3d N = 2 theories: pairs of M5 branes wrapped on a 3-manifold. Using the ansantz of R-flow, we study 3-manifolds consisting of Riemann surfaces fibered over R. When the construction is non-singular, the resulting IR physics is described by a free abelian Chern-Simons theory. The mathematical data of a tangle captures the data of the gauge theory, and the Reidemeister equivalances on tangles correspond to dualities of physical descriptions. To obtain interacting matter, we allow singularities in the construction. By extending the tangle description to these singular cases, we find a set of generalized Reidemeister moves that

  15. Multi-watt 589nm fiber laser source

    SciTech Connect

    DAWSON, J W; DROBSHOFF, A D; BEACH, R J; MESSERLY, M J; PAYNE, S A; BROWN, A; PENNINGTON, D M; BAMFORD, D J; SHARPE, S J; COOK, D J

    2006-01-19

    We have demonstrated 3.5W of 589nm light from a fiber laser using periodically poled stoichiometric Lithium Tantalate (PPSLT) as the frequency conversion crystal. The system employs 938nm and 1583nm fiber lasers, which were sum-frequency mixed in PPSLT to generate 589nm light. The 938nm fiber laser consists of a single frequency diode laser master oscillator (200mW), which was amplified in two stages to >15W using cladding pumped Nd{sup 3+} fiber amplifiers. The fiber amplifiers operate at 938nm and minimize amplified spontaneous emission at 1088nm by employing a specialty fiber design, which maximizes the core size relative to the cladding diameter. This design allows the 3-level laser system to operate at high inversion, thus making it competitive with the competing 1088nm 4-level laser transition. At 15W, the 938nm laser has an M{sup 2} of 1.1 and good polarization (correctable with a quarter and half wave plate to >15:1). The 1583nm fiber laser consists of a Koheras 1583nm fiber DFB laser that is pre-amplified to 100mW, phase modulated and then amplified to 14W in a commercial IPG fiber amplifier. As a part of our research efforts we are also investigating pulsed laser formats and power scaling of the 589nm system. We will discuss the fiber laser design and operation as well as our results in power scaling at 589nm.

  16. The effect of viewing angle on the spectral behavior of a Gd plasma source near 6.7 nm

    SciTech Connect

    O'Gorman, Colm; Li Bowen; Cummins, Thomas; Dunne, Padraig; Sokell, Emma; O'Sullivan, Gerry; Otsuka, Takamitsu; Yugami, Noboru; Higashiguchi, Takeshi; Jiang Weihua; Endo, Akira

    2012-04-02

    We have demonstrated the effect of viewing angle on the extreme ultraviolet (EUV) emission spectra of gadolinium (Gd) near 6.7 nm. The spectra are shown to have a strong dependence on viewing angle when produced with a laser pulse duration of 10 ns, which may be attributed to absorption by low ion stages of Gd and an angular variation in the ion distribution. Absorption effects are less pronounced at a 150-ps pulse duration due to reduced opacity resulting from plasma expansion. Thus for evaluating source intensity, it is necessary to allow for variation with both viewing angle and target orientation.

  17. Quantum confinement in metal nanofilms: Optical spectra

    NASA Astrophysics Data System (ADS)

    Khmelinskii, Igor; Makarov, Vladimir I.

    2016-05-01

    We report optical absorption and photoluminescence spectra of Au, Fe, Co and Ni polycrystalline nanofilms in the UV-vis-NIR range, featuring discrete bands resulting from transverse quantum confinement. The film thickness ranged from 1.1 to 15.6 nm, depending on the material. The films were deposited on fused silica substrates by sputtering/thermo-evaporation, with Fe, Co and Ni protected by a SiO2 film deposited on top. The results are interpreted within the particle-in-a-box model, with the box width equal to the mass thickness of the nanofilm. The transverse-quantized energy levels and transition energies scale as the inverse square of the film thickness. The calculated values of the effective electron mass are 0.93 (Au), 0.027 (Fe), 0.21 (Co) and 0.16 (Ni), in units of mo - the mass of the free electron, being independent on the film thickness. The uncertainties in the effective mass values are ca. 2.5%, determined by the film thickness calibration. The second calculated model parameter, the quantum number n of the HOMO, was thickness-independent in Au (5.00) and Fe (6.00), and increased with the film thickness in Co (from 7 to 9) and Ni (from 7 to 11). The transitions observed in the absorbance all start at the level n and correspond to Δn=+1, +2, +3, etc. The photoluminescence bands exhibit large Stokes shifts, shifting to higher energies with the increased excitation energy. The photoluminescence quantum yields grow linearly with the excitation energy, showing evidence of multiple exciton generation. A prototype Fe-SnO2 nanofilm photovoltaic cell demonstrated at least 90% quantum yield of photoelectrons at 77 K.

  18. 322 W single-mode Yb-doped all-fiber laser operated at 1120 nm

    NASA Astrophysics Data System (ADS)

    Zhang, Hanwei; Xiao, Hu; Zhou, Pu; Zhang, Kun; Wang, Xiaolin; Xu, Xiaojun

    2014-05-01

    An all-fiber, high-power, spectrally clean, single-mode Yb-doped fiber oscillator at 1120 nm wavelength is demonstrated. By optimizing the reflectivity of the output coupler and the length of the gain fiber, an output power of 322 W and an optical efficiency of 71% have been achieved. The output power, spectra, and bandwidth broadening are presented and briefly discussed. The power scaling capability of the cavity is analyzed on the basis of the thermal effect, and a maximal thermal-damage-free output power of 450 W could be expected.

  19. Polarization properties of lidar scattering from clouds at 347 nm and 694 nm.

    PubMed

    Pal, S R; Carswell, A I

    1978-08-01

    The polarization characteristics of lidar scattering from cumulus and low-lying shower clouds have been measured with a system operating at 694 nm (red) and 347 nm (blue). The backscatter profiles of the polarization components as well as of the total intensity of the return are presented and discussed for the two wavelengths. The linear depolarization ratio delta, which can be used as a measure of the unpolarized multiple scattering, has been obtained at both wavelengths. This quantity has a very low value at cloud base for both wavelengths and increases with pulse penetration. The blue registers generally higher values of a within the cloud. The measured total intensity backscatter functions for both wavelengths are presented and discussed in relation to theoretical calculations of cloud models.

  20. Analysis of excited-state Faraday anomalous dispersion optical filter at 1529 nm.

    PubMed

    Xiong, Junyu; Yin, Longfei; Luo, Bin; Guo, Hong

    2016-06-27

    In this work, a detailed theoretical analysis of 1529 nm ES-FADOF (excited state Faraday anomalous dispersion optical filter) based on rubidium atoms pumped by 780 nm laser is introduced, where Zeeman splitting, Doppler broadening, and relaxation processes are considered. Experimental results are carefully compared with the derivation. The results prove that the optimal pumping frequency is affected by the working magnetic field. The population distribution among all hyperfine Zeeman sublevels under the optimal pumping frequency has also been obtained, which shows that 85Rb atoms are the main contribution to the population. The peak transmittance above 90% is obtained, which is in accordance with the experiment. The calculation also shows that the asymmetric spectra observed in the experiment are caused by the unbalanced population distribution among Zeeman sublevels. This theoretical model can be used for all kinds of calculations for FADOF. PMID:27410643

  1. Pressure spectra and cross spectra at an area contraction in a ducted combustion system

    NASA Technical Reports Server (NTRS)

    Miles, J. H.; Raftopoulos, D. D.

    1980-01-01

    Pressure spectra and cross-spectra at an area contraction in a liquid fuel, ducted, combustion noise test facility are analyzed. Measurements made over a range of air and fuel flows are discussed. Measured spectra are compared with spectra calculated using a simple analytical model.

  2. Reflectance spectra of primitive chondrites

    NASA Astrophysics Data System (ADS)

    Trigo-Rodríguez, J. M.; Moyano-Cambero, C. E.; Llorca, J.

    2013-05-01

    We are studying a wide sample of pristine carbonaceous chondrites from the NASA Antarctic collection in order to get clues on the physico-chemical processes occurred in the parent bodies of these meteorites. We are obtaining laboratory reflectance spectra of different groups of carbonaceous chondrites, but here we focus in CM and CI chondrites. We discuss the main spectral features that can be used to identify primitive carbonaceous asteroids by remote sensing techniques. Two different spectrometers were used covering the entire 0.3 to 30 μm electromagnetic window. Only a handful of Near Earth Objects (NEOs) exhibit bands or features clearly associated with aqueous alteration. Among them are the target asteroids of Osiris Rex and Marco Polo-R missions.

  3. Graviton spectra in string cosmology

    SciTech Connect

    Galluccio, Massimo; Litterio, Marco; Occhionero, Franco

    1996-08-01

    We propose to uncover the signature of a stringy era in the primordial Universe by searching for a prominent peak in the relic graviton spectrum. This feature, which in our specific model terminates an ω³ increase and initiates an ω⁻⁷ decrease, is induced during the so far overlooked bounce of the scale factor between the collapsing deflationary era (or pre-Big Bang) and the expanding inflationary era (or post-Big Bang). We evaluate both analytically and numerically the frequency and the intensity of the peak and we show that they may likely fall in the realm of the new generation of interferometric detectors. The existence of a peak is at variance with ordinarily monotonic (either increasing or decreasing) graviton spectra of canonical cosmologies; its detection would therefore offer strong support to string cosmology.

  4. Graviton Spectra in String Cosmology

    SciTech Connect

    Galluccio, M.; Occhionero, F.; Litterio, M.

    1997-08-01

    We propose to uncover the signature of a stringy era in the primordial Universe by searching for a prominent peak in the relic graviton spectrum. This feature, which in our specific model terminates an {omega}{sup 3} increase and initiates an {omega}{sup {minus}7} decrease, is induced during the so far overlooked bounce of the scale factor between the collapsing deflationary era (or pre{endash}big bang) and the expanding inflationary era (or post{endash}big bang). The frequency and the intensity of the peak may likely fall in the realm of the new generation of interferometric detectors. The existence of a peak, at variance with ordinarily monotonic graviton spectra, would therefore offer strong support to string cosmology. {copyright} {ital 1997} {ital The American Physical Society}

  5. Analysis of multi-mode to single-mode conversion at 635 nm and 1550 nm

    NASA Astrophysics Data System (ADS)

    Zamora, Vanessa; Bogatzki, Angelina; Arndt-Staufenbiel, Norbert; Hofmann, Jens; Schröder, Henning

    2016-03-01

    We propose two low-cost and robust optical fiber systems based on the photonic lantern (PL) technology for operating at 635 nm and 1550 nm. The PL is an emerging technology that couples light from a multi-mode (MM) fiber to several single-mode (SM) fibers via a low-loss adiabatic transition. This bundle of SM fibers is observed as a MM fiber system whose spatial modes are the degenerate supermodes of the bundle. The adiabatic transition allows that those supermodes evolve into the modes of the MM fiber. Simulations of the MM fiber end structure and its taper transition have been performed via functional mode solver tools in order to understand the modal evolution in PLs. The modelled design consists of 7 SM fibers inserted into a low-index capillary. The material and geometry of the PLs are chosen such that the supermodes match to the spatial modes of the desired step-index MM fiber in a moderate loss transmission. The dispersion of materials is also considered. These parameters are studied in two PL systems in order to reach a spectral transmission from 450 nm to 1600 nm. Additionally, an analysis of the geometry and losses due to the mismatching of modes is presented. PLs are typically used in the fields of astrophotonics and space photonics. Recently, they are demonstrated as mode converters in telecommunications, especially focusing on spatial division multiplexing. In this study, we show the use of PLs as a promising interconnecting tool for the development of miniaturized spectrometers operating in a broad wavelength range.

  6. Line Coupling in Atmospheric Spectra

    NASA Technical Reports Server (NTRS)

    Tipping, R. H.

    1996-01-01

    The theoretical modeling of atmospheric spectra is important for a number of different applications: for instance, in the determination of minor atmospheric constituents such as ozone, carbon dioxide, CFC's etc.; in monitoring the temperature profile for climate studies; and in measuring the incoming and outgoing radiation to input into global climate models. In order to accomplish the above mentioned goal, one needs to know the spectral parameters characterizing the individual spectral lines (frequency, width, strength, and shape) as well as the physical parameters of the atmosphere (temperature, abundances, and pressure). When all these parameters are known, it is usually assumed that the resultant spectra and concomitant absorption coefficient can then be calculated by a superposition of individual profiles of appropriate frequency, strength and shape. However, this is not true if the lines are 'coupled'. Line coupling is a subtle effect that takes place when lines of a particular molecule overlap in frequency. In this case when the initial states and the final states of two transitions are connected by collisions, there is a quantum interference resulting in perturbed shapes. In general, this results in the narrowing of Q-branches (those in which the rotational quantum number does not change), and vibration-rotational R- and P branches (those in which the rotational quantum number changes by +/- 1), and in the spectral region beyond band heads (regions where the spectral lines pile up due to centrifugal distortion). Because these features and spectral regions are often those of interest in the determination of the abundances and pressure-temperature profiles, one must take this effect into account in atmospheric models.

  7. Performance comparison of bismuth/erbium co-doped optical fibre by 830 nm and 980 nm pumping

    NASA Astrophysics Data System (ADS)

    Yan, Binbin; Luo, Yanhua; Zareanborji, Amirhassan; Xiao, Gui; Peng, Gang-Ding; Wen, Jianxiang

    2016-10-01

    The performance of bismuth/erbium co-doped fibre (BEDF) by 830 nm and 980 nm pumping has been studied in detail, including the small signal absorption, pump absorption, emission, gain and excited state absorption (ESA). Based on the study, energy transition diagrams of BEDF under 830 nm or 980 nm pumping are proposed to clarify the spectroscopic properties. The results demonstrate the advantages of 830 nm pumping for BEDF over 980 nm pumping when considering the absorption, pumping efficiency, excited state absorption and optical amplification.

  8. Electron-induced single event upsets in 28 nm and 45 nm bulk SRAMs

    DOE PAGES

    Trippe, J. M.; Reed, R. A.; Austin, R. A.; Sierawski, B. D.; Weller, R. A.; Funkhouser, E. D.; King, M. P.; Narasimham, B.; Bartz, B.; Baumann, R.; et al

    2015-12-01

    In this study, we present experimental evidence of single electron-induced upsets in commercial 28 nm and 45 nm CMOS SRAMs from a monoenergetic electron beam. Upsets were observed in both technology nodes when the SRAM was operated in a low power state. The experimental cross section depends strongly on both bias and technology node feature size, consistent with previous work in which SRAMs were irradiated with low energy muons and protons. Accompanying simulations demonstrate that δ-rays produced by the primary electrons are responsible for the observed upsets. Additional simulations predict the on-orbit event rates for various Earth and Jovian environmentsmore » for a set of sensitive volumes representative of current technology nodes. The electron contribution to the total upset rate for Earth environments is significant for critical charges as high as 0.2 fC. This value is comparable to that of sub-22 nm bulk SRAMs. Similarly, for the Jovian environment, the electron-induced upset rate is larger than the proton-induced upset rate for critical charges as high as 0.3 fC.« less

  9. Electron-induced single event upsets in 28 nm and 45 nm bulk SRAMs

    SciTech Connect

    Trippe, J. M.; Reed, R. A.; Austin, R. A.; Sierawski, B. D.; Weller, R. A.; Funkhouser, E. D.; King, M. P.; Narasimham, B.; Bartz, B.; Baumann, R.; Schrimpf, R. D.; Labello, R.; Nichols, J.; Weeden-Wright, S. L.

    2015-12-01

    In this study, we present experimental evidence of single electron-induced upsets in commercial 28 nm and 45 nm CMOS SRAMs from a monoenergetic electron beam. Upsets were observed in both technology nodes when the SRAM was operated in a low power state. The experimental cross section depends strongly on both bias and technology node feature size, consistent with previous work in which SRAMs were irradiated with low energy muons and protons. Accompanying simulations demonstrate that δ-rays produced by the primary electrons are responsible for the observed upsets. Additional simulations predict the on-orbit event rates for various Earth and Jovian environments for a set of sensitive volumes representative of current technology nodes. The electron contribution to the total upset rate for Earth environments is significant for critical charges as high as 0.2 fC. This value is comparable to that of sub-22 nm bulk SRAMs. Similarly, for the Jovian environment, the electron-induced upset rate is larger than the proton-induced upset rate for critical charges as high as 0.3 fC.

  10. Uncertainties of the Intensity of the 1130 nm Band of Water Vapor

    NASA Technical Reports Server (NTRS)

    Giver, L. P.; Pilewskie, P.; Gore, W. J.; Chackerian, C., Jr.; Varanasi, P.; Bergstrom, R.; Freedman, R. S.

    2001-01-01

    Belmiloud, et al have recently suggested that the HITRAN line intensities in the 1130 nm water vapor band are much too weak. Giver, et at corrected unit conversion errors to make the HITRAN intensities compatible with the original measurements of Mandin, et al, but Belmiloud, et al believe that many of those line intensity measurements were too weak, and they propose the total intensity of the 1130 nm water vapor band is 38% stronger than the sum of the HITRAN line intensities in this region. We have made independent assessments of this proposal using 2 spectra obtained with the Ames 25 meter base path White cell. The first was made using the moderate resolution (8 nm) solar spectral flux radiometer (SSFR) flight instrument with a White cell absorbing path of 506 meters and 10 torr water vapor pressure. Modeling this spectrum using the HITRAN linelist gives a reasonable match, and the model is not compatible when the HITRAN line intensities are increased by 38%. The second spectrum was obtained with a White cell path of 1106 meters and 12 torr water vapor pressure, using a Bomem FTIR with near Doppler width resolution. This spectrum is useful for measuring intensities of isolated weak lines to compare with the measurements of Mandin, et al. Unfortunately, as Belmiloud et al point out, at these conditions the strong lines are much too saturated for good intensity measurements. Our measurements of the weak lines are in reasonable agreement with those of Mandin, et al. Neither of our spectra supports the proposal of Belmiloud et al for a general 38% increase of the absorption intensity in the 1130 nm water vapor band.

  11. Temperature and pH effects on myoglobin optical absorption spectra

    NASA Astrophysics Data System (ADS)

    Ciesielski, Wayne A.; Arakaki, Lorilee S. L.; Schenkman, Kenneth A.

    2005-03-01

    Myoglobin is an important intracellular oxygen transport molecule in muscle. Oxygen binding to myoglobin can be determined spectroscopically due to differences in absorption of oxymyoglobin and deoxymyoglobin. Myoglobin oxygenation can be used as a measure of intracellular oxygen tension in muscle. We sought to determine the effects of differences in temperature and pH on myoglobin absorption spectra in the near-infrared spectral region. Transmission spectra were taken of pure solutions of oxymyoglobin and deoxymyoglobin at 10°, 20°, 30°, and 40°C at pH values of 6.0, 7.0, and 8.0 (n=4). In second derivative spectra at 40°C, the deoxymyoglobin peak near 760 nm was shifted by 0.9-1.2 nm toward longer wavelengths relative to 10°C at constant pH. Differences in pH did not result in statistically significant shifts in this peak at constant temperature. Estimations of myoglobin saturation from myoglobin spectra with intermediate saturations were obtained by least squares (LS) and partial least squares (PLS) analyses. Both algorithms estimate myoglobin saturation with small root mean square errors (<1e-6) when component spectra and calibration set spectra are at the same temperature as test spectra (n=100). However, when spectra at 20°C or 40°C were used as component spectra in LS with test spectra at 30°C (all at pH 7.0), errors were 0.8% and 1.4%, respectively. PLS analysis of 30°C test spectra using 20°C or 40°C calibration set spectra yielded errors of 1.6% and 1.5%, respectively. When the PLS analysis is endpoint corrected, these errors become vanishingly small. These results demonstrate that peak shifts due to temperature are potential sources of error if calibration and test spectra differ by 10°C. These errors can be minimized by appropriate spectral analytic methods.

  12. Absolute spectral irradiance measurements of lightning from 375 to 880 nm

    NASA Technical Reports Server (NTRS)

    Orville, R. E.; Henderson, R. W.

    1984-01-01

    The time-integrated emissions from cloud-to-ground lightning have been recorded in the 375-880 nm region, using a spectrometer-detector and multichannel analyzer system capable of absolute spectral irradiance measurements. A schematic drawing of the detector-analyzer system is presented, and the experimental setup is described. A total of ten flashes containing 46 individual strikes were recorded and compared to recordings of 500 flashes from 1981. The average spectral irradiance from 375 to 695 nm for flashes at about 15 km was 3.5 x 10 to the -5th J/sq m per stroke with a standard deviation of 2.0 x 10 to the -5th and a range from 0.7 x 10 to the 0.7-6.8 x 10 to the -5th J/sq m per stroke. The average stroke spectra irradiance from 650 to 880 nm for the same strokes was 1.2 x 10 to the -5th, with a standard deviation of 0.7 x 10 to the -5th and a range from 0.5 to 3.2 x 10 to the -5th J/sq m per stroke. A summary table of spectral irradiance values in 50 nm increment is presented. Analysis of the spectral emission data show that unresolved neutral hydrogen lines (NI) at 744.2 nm were more intense than H-alpha emission at 656.3 nm. The strong emission of a flash with a continuing current was identified as cyanogen (CN) emission.

  13. OSIRIS Detections of a Tropospheric Aerosol that Absorbs at Wavelengths Near 350 nm - Black Carbon?

    NASA Astrophysics Data System (ADS)

    Degenstein, D. A.; Roth, C.; Bourassa, A. E.; Lloyd, N.

    2014-12-01

    The Canadian built OSIRIS instrument has been in operation onboard the Swedish spacecraft Odin since the autumn of 2001. During this 13 year period OSIRIS has recorded millions of spectra of the limb-scattered radiance in the wavelength range from 280 nm to 810 nm with approximately 1 nm spectral resolution. These measurements that scan tangents altitudes from 10 km to 65 km have primarily been used to retrieve stratospheric composition including vertical profiles of ozone, nitrogen dioxide, sulphate aerosol and bromine monoxide. The ozone retrieval is done is such a way that it uses the vertical radiance profile at 350 nm as a non-ozone absorbing reference measurement and it is these measurements that have serendipitously indicated the presence of an absorbing aerosol at tropospheric altitudes. At this time there is no indication of the exact composition of this absorber but it has characteristics that are curiously like those of black carbon. This poster will outline: the technique used to detect the black carbon from OSIRIS measurements; the wavelength dependence of a pseudo absorber used in the SASKTARN radiative transfer model to accurately simulate the OSIRIS measurements; and the geographical distribution of the detections of this pseudo absorber.

  14. C-doped mesoporous anatase TiO2 comprising 10nm crystallites.

    PubMed

    Xie, Chong; Yang, Shenghui; Li, Beibei; Wang, Hongkong; Shi, Jian-Wen; Li, Guodong; Niu, Chunming

    2016-08-15

    We report a C-doped mesoporous anatase TiO2 with high surface area synthesized using multi-walled carbon nanotube (MWCNT) mat as a "rigid" template and carbon doping source. The characterization by SEM, HRTEM, X-ray diffraction and nitrogen adsorption revealed that TiO2 samples have a porous structure which are figuratively a inverse copy of MWCNT network and pore walls are formed by interconnected TiO2 nanoparticles with average diameter of ∼10nm. We found that annealing temperatures from 400 to 1000°C before MWCNT template removal had very limited effect on particle size (∼10nm), surface area (112-129m(2)/g) and total pore volume (0.74-0.85m(2)/g) of the samples through a significantly delayed phase transition from anatase to rutile started at 800°C, resulting in only ∼9.1% conversion at 1000°C. The pore size distribution is in mesopore range from 6 to 60nm peaked at ∼24nm. XPS analysis showed a relatively strong C1s peak at 288.4eV, indicating C doping at Ti sites, which is responsible for red shift of adsorption edge of UV-vis spectra and photocatalytic activity in visible-light region. PMID:27179173

  15. C-doped mesoporous anatase TiO2 comprising 10nm crystallites.

    PubMed

    Xie, Chong; Yang, Shenghui; Li, Beibei; Wang, Hongkong; Shi, Jian-Wen; Li, Guodong; Niu, Chunming

    2016-08-15

    We report a C-doped mesoporous anatase TiO2 with high surface area synthesized using multi-walled carbon nanotube (MWCNT) mat as a "rigid" template and carbon doping source. The characterization by SEM, HRTEM, X-ray diffraction and nitrogen adsorption revealed that TiO2 samples have a porous structure which are figuratively a inverse copy of MWCNT network and pore walls are formed by interconnected TiO2 nanoparticles with average diameter of ∼10nm. We found that annealing temperatures from 400 to 1000°C before MWCNT template removal had very limited effect on particle size (∼10nm), surface area (112-129m(2)/g) and total pore volume (0.74-0.85m(2)/g) of the samples through a significantly delayed phase transition from anatase to rutile started at 800°C, resulting in only ∼9.1% conversion at 1000°C. The pore size distribution is in mesopore range from 6 to 60nm peaked at ∼24nm. XPS analysis showed a relatively strong C1s peak at 288.4eV, indicating C doping at Ti sites, which is responsible for red shift of adsorption edge of UV-vis spectra and photocatalytic activity in visible-light region.

  16. Spin wave eigenmodes in single and coupled sub-150 nm rectangular permalloy dots

    SciTech Connect

    Carlotti, G. Madami, M.; Tacchi, S.; Gubbiotti, G.; Dey, H.; Csaba, G.; Porod, W.

    2015-05-07

    We present the results of a Brillouin light scattering investigation of thermally excited spin wave eigenmodes in square arrays of either isolated rectangular dots of permalloy or twins of dipolarly coupled elements, placed side-by-side or head-to-tail. The nanodots, fabricated by e-beam lithography and lift-off, are 20 nm thick and have the major size D in the range between 90 nm and 150 nm. The experimental spectra show the presence of two main peaks, corresponding to modes localized either at the edges or in the center of the dots. Their frequency dependence on the dot size and on the interaction with adjacent elements has been measured and successfully interpreted on the basis of dynamical micromagnetic simulations. The latter enabled us also to describe the spatial profile of the eigenmodes, putting in evidence the effects induced by the dipolar interaction between coupled dots. In particular, in twinned dots the demagnetizing field is appreciably modified in proximity of the “internal edges” if compared to the “external” ones, leading to a splitting of the edge mode. These results can be relevant for the exploitation of sub-150 nm magnetic dots in new applications, such as magnonic metamaterials, bit-patterned storage media, and nano-magnetic logic devices.

  17. Automated identification of basalt spectra in Clementine lunar data

    NASA Astrophysics Data System (ADS)

    Antonenko, I.; Osinski, G. R.

    2011-06-01

    The identification of fresh basalt spectra plays an important role in lunar stratigraphic studies; however, the process can be time consuming and labor intensive. Thus motivated, we developed an empirically derived algorithm for the automated identification of fresh basalt spectra from Clememtine UVVIS data. This algorithm has the following four parameters and limits: BC Ratio=3(R950-R900)/(R900-R750)<1.1, CD Delta=(R1000-R950)/R750-1.09(R950-R900)/R750>0.003 and <0.06, B Slope=(R900-R750)/(3R750)<-0.012, and Band Depth=(R750-R950)/(R750-R415)>0.1, where R750 represents the unnormalized reflectance of the 750 nm Clementine band, and so on. Algorithm results were found to be accurate to within an error of 4.5% with respect to visual classification, though olivine spectra may be under-represented. Overall, fresh basalts identified by the algorithm are consistent with expectations and previous work in the Mare Humorum area, though accuracy in other areas has not yet been tested. Great potential exists in using this algorithm for identifying craters that have excavated basalts, estimating the thickness of mare and cryptomare deposits, and other applications.

  18. Improved performance 1590 nm Er:YLF laser

    SciTech Connect

    Marchbanks, R.D.; Petrin, R.R.; Cockroft, N.J.

    1994-12-01

    We present an improvement in the performance of a 1590 nm ER:YLF laser through simultaneous laser operation at 2717 nm. A slope efficiency of 7.0% with an output of 13.2 mW has been achieved with 971 nm pumping.

  19. Solar Spectrum Synthesis. I. A Sample Atlas from 224 to 300 nm

    NASA Astrophysics Data System (ADS)

    Kurucz, Robert L.; Avrett, Eugene H.

    1981-05-01

    We have developed sophisticated computer programs for determining solar and stellar atmospheric structure through the analysis of spectra. These programs allow us to treat the spectrum as a whole and to draw much stronger conclusions than would be apparent from individual spectral features. For a given LTE or non-LTE model atmosphere, the programs compute the emergent flux or the specific intensity at up to 20 angles. The spectrum can be broadened by macroturbulence and rotation; it can be modified by transmission through the Earth's atmosphere; it can be convolved with the instrumental profile; and it can finally be plotted together with the observed spectrum with each line labeled. In the opacity calculation, the lines are broadened by radiative, Stark, and van der Waals damping, and they can have isotopic and hyperfine splitting, autoionization, partial redistribution, or be merged into a continuum. The departure coefficients for ions treated in non-LTE in the model atmosphere calculation can be used in the spectrum synthesis programs for all lines of these ions, and highly ionized lines can be treated in the coronal approximation. The model atmosphere can have depth-dependent doppler shifts corresponding to large-scale motions. Using the Vernazza, Avrett, and Loeser models for the average quiet sun, we have computed theoretical solar spectra that include all available atomic and molecular line data. In this atlas we compare with the best available observed spectra in the 224- to 300-nm wavelength range, namely, the Kohl, Parkinson, and Kurucz (Harvard) center and limb rocket spectra in the range 224 to 300 nm; the Allen, McAllister, and Jefferies (Hawaii) disk center rocket spectrum for 268 to 293 nm; and the Brault and Testerman disk center spectrum taken at Kitt Peak for 294 to 300 nm. We also compare the observed spectra with each other. The existing spectra are noisy and do not have adequate resolution, so that it is difficult or impossible to identify weak

  20. Phase-matched frequency conversion below 150 nm in KBe2BO3F2.

    PubMed

    Nakazato, Tomoharu; Ito, Isao; Kobayashi, Yohei; Wang, Xiaoyang; Chen, Chuangtian; Watanabe, Shuntaro

    2016-07-25

    Sum frequency mixing has been demonstrated below 150 nm in KBeBO3F2 by using the fundamental with its fourth harmonic of a 6 kHz Ti: sapphire laser system. The wavelength of 149.8 nm is the shortest ever obtained to our knowledge by phase matching in nonlinear crystals. The output powers were 3.6 μW at 149.8 nm and 110 μW at 154.0 nm, respectively. The phase matching angles measured from 149.8 to 158.1 nm are larger by 3-4 degrees than those expected from the existing Sellmeier equation. The measured transmission spectra of KBeBO3F2 crystals support the generation of coherent radiation below 150 nm. PMID:27464165

  1. Vacuum ultraviolet reflectance spectra of groups L, LL, and E chondrites and of achondrites

    NASA Technical Reports Server (NTRS)

    Wagner, J. K.; Cohen, A. J.; Hapke, B. W.; Partlow, W. D.

    1980-01-01

    The reflectance spectra of individual meteorites of all classes are being measured in the vacuum ultraviolet (VUV) spectral wavelength region from 89 to 248 nm to evaluate the potential of VUV spectroscopy as a remote sensing method for planetary studies. In the present investigation, specimens of 15 group L chondrites, 13 group LL chondrites, 7 group E chondrites, and 18 achondrites were studied. Spectra were measured of both polished thin sections and powders of the meteorites, where both were available. Attention is given to measurements of mineral standards, shock effects, and meteorite data. It is concluded that the VUV spectra of meteorites should provide a useful basis for comparisons with spectra of asteroids and comet nuclei taken from spacecraft. VUV spectroscopy should make it possible to identify the major minerals present in a meteorite or asteroid.

  2. Aerosol-fluorescence spectrum analyzer: real-time measurement of emission spectra of airborne biological particles

    NASA Astrophysics Data System (ADS)

    Hill, Steven C.; Pinnick, Ronald G.; Nachman, Paul; Chen, Gang; Chang, Richard K.; Mayo, Michael W.; Fernandez, Gilbert L.

    1995-10-01

    We have assembled an aerosol-fluorescence spectrum analyzer (AFS), which can measure the fluorescence spectra and elastic scattering of airborne particles as they flow through a laser beam. The aerosols traverse a scattering cell where they are illuminated with intense (50 kW/cm 2) light inside the cavity of an argon-ion laser operating at 488 nm. This AFS can obtain fluorescence spectra of individual dye-doped polystyrene microspheres as small as 0.5 mu m in diameter. The spectra obtained from microspheres doped with pink and green-yellow dyes are clearly different. We have also detected the fluorescence spectra of airborne particles (although not single particles) made from various

  3. Detection of cervical cancer by fluorescence emission and stokes' shift spectra of blood and urine

    NASA Astrophysics Data System (ADS)

    Masilamani, V.; Vijmasi, T.; AlSalhi, M.; Govindarajan, K.; VijayaRaghavan, A. P.; Rai, Ram Rathan

    2011-03-01

    In this paper we present the results of a study to distinguish cervical cancer patients [ N=50] from healthy subjects [N=50] based on the Fluorescence Emission Spectra [FES] and Stokes' Shift Spectra [SSS] of blood and urine. FES was obtained from the cellular fraction of blood and urine by excitation at 400 nm. SSS was obtained from blood plasma and urine with Δλ of 70nm. In the FES of blood cellular fraction, the ratio of intensity of the two bands due to neutral porphyrin and basic porphyrin [I630 / I580] was 1 for normal controls and 3 for cervical cancers. In the SSS of plasma, the average ratio of intensity of the two bands due to tryptophan and collagen [I305 nm / I340 nm] was 1.9 for normal controls, 1.1 for early cervical cancers and 0.9 for advanced cervical cancers In the SSS of urine, the ratio of intensity of the two bands due to flavin and NADH [I450 nm / I360 nm] was 0.2 for normal controls and 0.8 for cancer patients. A discriminant analysis combining all three parameters showed a sensitivity of 80% and specificity of 78% for this technique. In this study we show that fluorescence spectroscopy of blood and urine could develop into a promising technique for non-invasive diagnosis and screening of cervical cancers and would appropriately supplement or complement currently used techniques.

  4. Continuous-wave simultaneous dual-wavelength operation at 912 nm and 1063 nm in Nd:GdVO4

    NASA Astrophysics Data System (ADS)

    Lünstedt, K.; Pavel, N.; Petermann, K.; Huber, G.

    2007-01-01

    A continuous-wave, diode-pumped Nd:GdVO4 thin disk laser with simultaneous dual-wavelength emission at the 912 nm 4 F 3/2→4 I 9/2 quasi-three-level transition and the 1063 nm 4 F 3/2→4 I 11/2 four-level transition is demonstrated and analyzed. Output powers of 1.7 W at 912 nm and of 1.6 W at 1063 nm were achieved simultaneously from a 0.3-at.%, 300-μm thick Nd:GdVO4 crystal that was multi-pass excited with 26.8 W of available diode pump power. Second harmonic generation to 456 nm with LiB3O5 yielded 0.96 W in 912 nm single-wavelength operation and 0.73 W in 912 nm/1063 nm dual-wavelength operation.

  5. From the nm to the Mm

    NASA Astrophysics Data System (ADS)

    Villa, I. M.

    2003-12-01

    Tectonic models for the evolution of an orogen start at the Mm scale, and use field work on smaller subunits at the km scale and rocks collected at the m scale. At the mm scale, minerals are identified, analyzed by mass spectrometry, their "cooling ages" assigned to a specific closure temperature, a cooling rate attributed to a particular tectonic regime, and a large body of self-referential literature is the product of an oiled machinery. Problems become apparent if one attempts to harmonize mm-scale science with the nasty little details at even smaller scales. Atoms are invisible to the naked eye (unlike the minerals mentioned above) and their actual behavior is, or was, only accessible to indirect argumentations and simplified calculations. Increased computing power now allows calculating the transport of atoms in a crystal from the Schr”dinger equation: results do not fit 19th century continuum physics for infinitely dilute solutions (Fick's and Arrhenius' "laws"). Moreover, improved nanochemical analyses allow characterizing the supposedly homogeneous mineral matrix. TEM images show how layers or chains in pristine minerals are substituted in a non-periodic way by alteration products. EMP analyses show the almost ubiquitous presence of razor-sharp boundaries rather than Erf profiles. Disequilibrium recrystallization textures thus prevail over diffusive reequilibration; diffusion sensu stricto is shown to be a much slower process than heterochemical replacement. Alterability sequences are well known to surface scientists: e.g. halite, olivine, biotite, muscovite, zircon. Such sequences are reflected in the isotopic retentivity. The link only becomes clear at the nm scale: isotopic exchange occurs during the replacement reactions that affect all rocks on their retrograde P-T evolution. This is sufficient to explain why zircons record higher isotopic ages than muscovites, which in turn undergo less isotope exchange than biotites etc. While there is a vague

  6. Blind extraction of exoplanetary spectra

    NASA Astrophysics Data System (ADS)

    Morello, Giuseppe; Waldmann, Ingo P.; Tinetti, Giovanna

    2016-06-01

    In the last decade, remote sensing spectroscopy enabled characterization of the atmospheres of extrasolar planets. Transmission and emission spectra of tens of transiting exoplanets have been measured with multiple instruments aboard Spitzer and Hubble Space Telescopes as well as ground-based facilities, revealing the presence of atomic, ionic and molecular species in their atmospheres, and constraining their temperature and pressure profiles.Early analyses were somehow heuristic both in measuring the spectra and in their interpretation, leading to some controversies in the literature.A photometric precision of 0.01% is necessary to detect the atmospheric spectral modulations. Current observatories, except Kepler, were not designed to achieve this precision. Data reduction is necessary to minimize the effect of instrument systematics in order to achieve the target precision. In the past, parametric models have extensively been used by most teams to remove correlated noise with the aid of auxiliary information of the instrument, the so-called optical state vectors (OSVs). Such OSVs can include inter- and intra-pixel position of the star or its spectrum, instrument temperatures and inclinations, and/or other parameters. In some cases, different parameterizations led to discrepant results.We recommend the use of blind non-parametric data detrending techniques to overcome those issues. In particular, we adopt Independent Component Analysis (ICA), i.e. a blind source separation (BSS) technique to disentangle the multiple instrument systematics and astrophysical signals in transit/eclipse light curves. ICA does not require a model for the systematics, and for this reason, it can be applied to any instrument with little changes, if any. ICA-based algorithms have been applied to Spitzer/IRAC and synthetic observations in photometry (Morello et al. 2014, 2015, 2016; Morello 2015) and to Hubble/NICMOS and Spitzer/IRS in spectroscopy (Waldmann 2012, 2014, Waldmann et al. 2013

  7. Refractory sea salt CCN spectra

    NASA Astrophysics Data System (ADS)

    Noble, S.; Hudson, J. G.

    2012-12-01

    Hudson et al. (2011; H11) showed a substantial sea salt (NaCl) CCN contribution for low critical supersaturation (Sc) CCN (< 0.1%), which was a positive function of horizontal wind speed (U) at the ocean surface in the RICO project in the Caribbean. Somewhat similar results were found over the Pacific near California in spite of a factor of 3 higher average CCN concentrations. Results were obscured over the mid Pacific in PASE because of the lack of cloud scavenging (H11). The results were obtained by CCN spectral volatility measurements, which remove all but the refractory CCN that survive heating to 300 degrees C, which are only NaCl. Fig. 1 shows that ambient CCN concentrations were uncorrelated with U but that refractory CCN were correlated with U in RICO and POST. Fig. 2 compares low altitude average refractory CCN spectra during flights with various noted mean U. The two POST flights and the RICO flights displayed here show the same dependence on U that was quantified by H11. The higher concentrations for PASE in relation to U are due to the lack of cloud scavenging, which allowed higher concentrations to build up that are thus not related to the simultaneously measured U. The abundant clouds of RICO and POST provided enough removal of CCN that sea salt CCN were correlated with simultaneously measured U. These measurements have begun the quantification of this most definite natural CCN source. This is needed in order to assess the impact of anthropogenic CCN on clouds; i.e., the indirect aerosol effect. Hudson, J.G., S. Noble, and V. Jha, 2011: On the relative role of sea salt cloud condensation nuclei (CCN). J. Atmos. Chem. Volume 68, Number 1, Pages 71-88, DOI: 10.1007/s10874-011-9210-5. Fig. 1. Correlation coefficients (R) between CCN concentrations at various S and wind speed for ambient CCN (all) and refractory CCN. Fig. 2. Flight averaged refractory CCN spectra.

  8. Resonance raman spectroscopic study of alumina-supported vanadium oxide catalysts with 220 and 287 nm excitation.

    SciTech Connect

    Kim, H. S.; Stair, P. C.; Chemical Sciences and Engineering Division; Northwestern Univ.

    2009-01-01

    We present detailed resonance Raman spectroscopic results excited at 220 and 287 nm for alumina-supported VO{sub x} catalysts. The anharmonic constant, harmonic wavenumber, anharmonic force constant, bond dissociation energy, and bond length change in the excited state for double bonded V{double_bond}O and single bonded V-O were obtained from fundamental and overtone frequencies. Totally symmetric and nontotally symmetric modes could be discerned and assigned on the basis of the overtone and combination progressions found in the resonance Raman spectra. Selective resonance enhancement of two different vibrational modes with two different excitation wavelengths was observed. This allowed us to establish a linear relationship between charge transfer energy and VO bond length and, consequently, to assign the higher-energy charge transfer band centered around 210?250 nm in the UV?vis spectra to the V{double_bond}O transition.

  9. The influence of surface reflectance anisotropy on estimation of soil properties

    NASA Astrophysics Data System (ADS)

    Bartholomeus, Harm; Roosjen, Peter; Clevers, Jan

    2014-05-01

    The spatial variation in soil properties is an important factor for agricultural management. Unmanned airborne vehicles (UAV's) equipped with a hyperspectral mapping system may provide these data, but anisotropic reflectance effects may have an influence on the derived soil properties. Besides influencing the reflectance, angular observations may deliver added information about soil properties. We investigated the anisotropic behavior of 59 soil samples with a large variation in soil composition, by measuring their reflectance (350-2500 nm) over 92 different angles using a robot-based laboratory goniometer system. The results show that the anisotropic behavior of the soils influences the measured reflectance significantly, which limits the accurate prediction of soil properties (OM and clay especially). However, prediction accuracies of OM increase when spectra are measured under specific angles. Prediction accuracies further increase when a combination of observation angles is being used. Apart from that, using UAV's the wavelength range is limited to about 1000 nm. In general, this will decrease the model performance, but our results show that this effect can largely be compensated by combining multiple observation angles. Altogether, we demonstrate that surface anisotropy influences the prediction of soil properties negatively. This effect can be reduced by combining spectra acquired under different angles. Moreover, predictions can be improved if combinations of different observation angles are used.

  10. Picosecond laser texturization of mc-silicon for photovoltaics: A comparison between 1064 nm, 532 nm and 355 nm radiation wavelengths

    NASA Astrophysics Data System (ADS)

    Binetti, Simona; Le Donne, Alessia; Rolfi, Andrea; Jäggi, Beat; Neuenschwander, Beat; Busto, Chiara; Frigeri, Cesare; Scorticati, Davide; Longoni, Luca; Pellegrino, Sergio

    2016-05-01

    Self-organized surface structures were produced by picosecond laser pulses on multi-crystalline silicon for photovoltaic applications. Three different laser wavelengths were employed (i.e. 1064 nm, 532 nm and 355 nm) and the resulting morphologies were observed to effectively reduce the reflectivity of the samples after laser irradiation. Besides, a comparative study of the laser induced subsurface damage generated by the three different wavelengths was performed by confocal micro-Raman, photoluminescence and transmission electron microscopy. The results of both the structural and optical characterization showed that the mc-Si texturing performed with the laser at 355 nm provides surface reflectivity between 11% and 8% over the spectral range from 400 nm to 1 μm, while inducing the lowest subsurface damage, located above the depletion region of the p-n junction.

  11. Study of absorption spectra of gasolines and other hydrocarbon mixtures in the second overtone region of the CH3, CH2, CH groups

    NASA Astrophysics Data System (ADS)

    Muradov, V. G.; Sannikov, D. G.

    2007-03-01

    We have obtained experimental and model absorption spectra for individual hydrocarbons (toluene, benzene, n-heptane, and iso-octane) and their mixtures in the near IR range (λ = 1080 1220 nm). We model the spectra of nonsynthetic gasolines obtained under the same conditions by combining the spectra of three pure hydrocarbons. We show that the octane number of the studied gasoline is linearly related to the toluene (or benzene) concentrations in the model mixture.

  12. Spectroscopic Measurements of Impurity Spectra on the EAST Tokamak

    NASA Astrophysics Data System (ADS)

    Fu, Jia; Li, Yingying; Shi, Yuejiang; Wang, Fudi; Zhang, Wei; Lv, Bo; Huang, Juan; Wan, Baonian; Zhou, Qian

    2012-12-01

    Ultraviolet (UV) and visible impurity spectra (200~750 nm) are commonly used to study plasma and wall interactions in magnetic fusion plasmas. Two optical multi-channel analysis (OMA) systems have been installed for the UV-visible spectrum measurement on EAST. These two OMA systems are both equipped with the Czerny-Turner (C-T) type spectrometer. The upper vacuum vessel and inner divertor baffle can be viewed simultaneously through two optical lenses. The OMA1 system is mainly used for multi-impurity lines radiation measurement. A 280 nm wavelength range can be covered by a 300 mm focal length spectrometer equipped with a 300 grooves/mm grating. The Dα/Hα line shapes can be resolved by the OMA2 system. The focal length is 750 mm. The spectral resolution can be up to 0.01 nm using a 1800 grooves/mm grating. The impurity behaviour and hydrogen ratio evolution after boroniztion, lithium coating, and siliconization are compared. Lithium coating has shown beneficial effects on the reduction of edge recycling and low Z impurity (C, O) influx. The impurity expelling effect of the divertor configuration is also briefly discussed through multi-channels observation of OMA1 system.

  13. Interference patterning of gratings with a period of 150 nm at a wavelength of 157 nm

    NASA Astrophysics Data System (ADS)

    Fuetterer, Gerald; Herbst, Waltraud; Rottstegge, Joerg; Ferstl, Margit; Sebald, Michael; Schwider, Johannes

    2002-07-01

    A system producing an optical pattern with a high spatial frequency at (lambda) equals 157 nm has been built to be used as a photoresist tool for the 157 nm lithography. In order to generate a test pattern with a high spatial frequency, two-beam interference was used to overcome the limits of existing mask-projection systems using numerical apertures up to 0.65. In order to work without phase lock techniques a e-beam phase grating was used for providing the two interfering wave fronts for the generation of 150 nm-structures. The phase grating is illuminated under the Bragg-angle. Only two diffraction orders propagate and the other orders are evanescent. The interference pattern resulting in the region of the overlap of the propagated orders is a true two-beam pattern of the same period as the e-beam mask. The photoresist coated wafer is placed in the plane of the interference pattern and is rigidly held by a mechanical fixture. The contrast of the interference pattern depends on the degree of spatial coherence of the excimer laser, on the coherence length, the polarization state of the beam used to illuminate the surface relief phase grating, and on the distance between the wafer and the surface relief phase grating. The degree of spatial coherence was increased by a restriction of the plane wave spectrum which has been attained at the cost of energy throughput. In addition, the TM-polarization was blocked. This was done by a polarizer and a spatial filter. The theoretical background of the experiment will be discussed as well as practical problems.

  14. Modelling asteroid spectra: few examples

    NASA Astrophysics Data System (ADS)

    Birlan, M.; Popescu, M.

    2011-10-01

    Asteroidal population comprises now more than 500,000 objects. Several observational techniques (spectroscopy, adaptive optics, photometry, polarimetry, radar,..) are used in order to obtain a mature understanding of an overall knowledge of this population. Spectroscopy can play a key role in determining the chemical composition and physical process that took place and modified the surface of asteroids. The development of telescopic instruments and the possibility to access them remotely allowed an increasing number of asteroid spectral measurements. The exploitation of spectral measurements is one of the important items to enlarge our science of surfaces of atmosphereless bodies. Spectral data of asteroids are in continuing growth. To exploit these spectral data we must account the global science of this population as well as the knowledge derived by studies of comparative planetology. The project M4AST (Modeling for Asteroids) consists in a database containing the results of these telescopic measurements and a set of applications for spectral analysis (Fig. 1). M4AST cover several aspects related to statistics of asteroids (taxonomy), mineralogical solutions using laboratory spectra from RELAB, and mineralogical modeling using space weathering effects corroborated with radiative transfer laws. M4AST was conceived to be available via a web interface and will be available for the scientific community. The abilities of these routines will be highlighted by few examples. Science derived via M4AST obtained for (222) Lucia, (809) Lundia, (810) Atossa, (1005) Arago, (1220) Crocus, and (4486) Mithra will be presented.

  15. Reflectance spectra of subarctic lichens

    NASA Technical Reports Server (NTRS)

    Petzold, Donald E.; Goward, Samuel N.

    1988-01-01

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the midlatitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 microns, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future.

  16. Band Spectra and Molecular Structure

    NASA Astrophysics Data System (ADS)

    Kronig, R. De L.

    2011-06-01

    Introduction; Part I. The Energy Levels of Diatomic Molecules and their Classification by Means of Quantum Numbers: 1. General foundations; 2. Wave mechanics of diatomic molecules; 3. Electronic levels; 4. Vibrational levels; 5. Rotational levels; 6. Stark and Zeeman effect; 7. Energy levels of polyatomic molecules; Part II. Fine Structure and Wave Mechanical Properties of the Energy Levels of Diatomic Molecules: 8. The perturbation function; 9. Rotational distortion of spin multiplets; 10. Fine structure; 11. Perturbations and predissociation; 12. Even and odd levels; 13. Symmetrical and antisymmetrical levels; Part III. Selection Rules and Intensities in Diatomic Molecules: 14. General foundations; 15. Electronic bands; 16. Vibrational bands; 17. Rotational bands; 18. Band spectra and nuclear structure; 19. Transitions in the Stark and Zeeman effect; Part IV. Macroscopic Properties of Molecular Gases: 20. Scattering; 21. Dispersion; 22. Kerr and Faraday effect; 23. Dielectric constants; 24. Magnetic susceptibilities; 25. Specific heats; Part V. Molecule Formation and Chemical Binding: 26. Heteropolar molecules; 27. Homopolar molecules. Chemical forces between two H-atoms and two He-atoms; 28. The general theory of homopolar compounds; Bibliography; Subject index.

  17. Interpretation of Nitroindolinospirobenzothiopyran Vibrational Spectra

    NASA Astrophysics Data System (ADS)

    Gladkov, L. L.; Khamchukov, Yu. D.; Lyubimov, A. V.

    2016-05-01

    The structures of four possible stereoisomers of the closed form of photochromic nitroindolinospirobenzothiopyran (NISTP) {1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzothiopyran-2,2'-(2H)-indoline]} were determined by the DFT method. The geometry of the most stable isomer was defined. Nitro-substitution changes mainly the lengths of bonds formed by S and N with spiro-atom Cs. According to the calculations, the CsS bond changes most and lengthens by 0.019 Å. It is shown that the S atom has large displacement amplitudes in normal modes assigned to Raman lines at 230, 285, 360, and 575 cm-1 and weak IR bands at 467 and 577 cm-1. Oscillations involving the nitro group are very active in Raman and IR spectra. Their frequencies are slightly lower than similar frequencies of nitrobenzene and nitroindolinospirobenzopyran, indicating a higher degree of vibrational coupling of the NO2 group with the NISTP molecular skeleton.

  18. X-ray spectra of supernova remnants

    NASA Technical Reports Server (NTRS)

    Szymkowiak, A. E.

    1985-01-01

    X-ray spectra were obtained from fields in three supernova remnants with the solid state spectrometer of the HEAO 2 satellite. These spectra, which contain lines from K-shell transitions of several abundant elements with atomic numbers between 10 and 22, were compared with various models, including some of spectra that would be produced by adiabatic phase remnants when the time-dependence of the ionization is considered.

  19. Infrared spectra of thyroid tumor tissues

    NASA Astrophysics Data System (ADS)

    Tolstorozhev, G. B.; Skornyakov, I. V.; Butra, V. A.

    2010-07-01

    We used infrared spectroscopy methods to study thyroid tumor tissues removed during surgery. The IR spectra of the surgical material are compared with data from histological examination. We show that in malignant neoplasms, the spectra of proteins in the region of C=O vibrations are different from the spectra of these substances in benign tumors and in tissues outside the pathological focus at a distance >1 cm from the margin of the tumor. The differences in the spectra are due to changes in the supermolecular structure of the proteins, resulting from rearrangement of the system of hydrogen bonds. We identify the spectral signs of malignant pathologies.

  20. Scatterometry measurement for gate ADI and AEI critical dimension of 28-nm metal gate technology

    NASA Astrophysics Data System (ADS)

    Huang, Yu-Hao; Chen, Howard; Shen, Kyle; Chen, H. H.; Yu, Chun Chi; Liao, J. H.; Zhang, Xiafang; Teo, Russell; Xu, Zhi-Qing; Yoo, Sungchul; Lin, Ching-Hung; Cheng, Chao-Yu; Lin, Jason

    2011-03-01

    This paper discusses the scatterometry-based metrology measurement of 28nm high k metal gate after-develop inspection (ADI) and after-etch inspection (AEI) layer structures. For these structures, the critical measurement parameters include side wall angle (SWA) and critical dimension (CD). For production process control of these structures, a metrology tool must utilize a non-destructive measurement technique, and have high sensitivity, precision and throughput. Spectroscopic critical dimension (SCD) metrology tools have been implemented in production for process control of traditional poly gate structures. For today's complex metal gate devices, extended SCD technologies are required. KLA-Tencor's new SpectraShape 8810 uses multi-azimuth angles and multi-channel optics to produce the high sensitivity and precision required for measurement of critical parameters on metal gate structures. Data from process of record (POR), focus-exposure matrix (FEM) and design of experiment (DOE) wafers are presented showing the performance of this new SCD tool on metal gate ADI and AEI process structures. Metal gate AEI scatterometry measurement results are also compared to transmission electron microscopy (TEM) reference measurements. These data suggest that the SpectraShape 8810 has the required sensitivity and precision to serve as a production process monitor for 28nm and beyond complex metal gate structures.

  1. Synthesis of gold nanorods with a longitudinal surface plasmon resonance peak of around 1250 nm

    NASA Astrophysics Data System (ADS)

    Nguyen, Thi Nhat Hang; Le Trinh Nguyen, Thi; Thanh Tuyen Luong, Thi; Thang Nguyen, Canh Minh; Nguyen, Thi Phuong Phong

    2016-03-01

    We prepared gold nanorods and joined them to chemicals such as tetrachloauric (III) acid trihydrate, silver nitrate, hydroquinone, hexadecyltrimethylammonium bromide, sodium hydroxide and sodium borohydride using the seed-mediated method. The combination of hydroquinone, with or without salicylic acid, influences the size of the gold nanorods, and this is demonstrated by the results of TEM images, UV-vis spectra and the value of the longitudinal surface plasmon resonance peak with respect to the UV-vis spectra. By changing the Ag+ ion and hydroquinone concentration and the combination of hydroquinone and salicylic acid, the size of the gold nanorods can be controlled and this is manifested by longitudinal surface plasmon resonance peaks forming between 875 and 1278 nm. In particular, sample E2 achieved a longitudinal surface plasmon peak at 1273 nm and an aspect ratio of more than 10 by modifying the hydroquinone to 2.5 mM and salicylic acid to 0.5 mM concentration in the growth solution.

  2. Delayed fluorescence spectra of intact leaves photoexcited by sunlight measured with a multichannel Fourier-transform chemiluminescence spectrometer

    NASA Astrophysics Data System (ADS)

    Akita, Saeka; Yano, Ayako; Ishii, Hiroshi; Satoh, Chikahiro; Akai, Nobuyuki; Nakata, Munetaka

    2013-06-01

    Delayed fluorescence spectra of intact leaves of Green pak choi (Brassica rapa var. chinensis) were measured with a multichannel Fourier-transform chemiluminescence spectrometer, which we developed recently. The intact samples, photoexcited by sunlight without artificial light sources, showed delayed fluorescence around 740 nm with a lifetime of ˜6 s. The observed spectra were deconvoluted into two Gaussian bands: the delayed fluorescence from photosystem II and photosystem I complexes. Their relative intensities depended on the chlorophyll concentration, but their wavelengths were unchanged.

  3. 9nm node wafer defect inspection using three-dimensional scanning, a 405nm diode laser, and a broadband source

    NASA Astrophysics Data System (ADS)

    Zhou, Renjie; Edwards, Chris; Bryniarski, Casey A.; Popescu, Gabriel; Goddard, Lynford L.

    2015-03-01

    We recently built a 405nm laser based optical interferometry system for 9nm node patterned wafer defect inspection. Defects with volumes smaller than 15nm by 90nm by 35nm have been detected. The success of defect detection relied on accurate mechanical scanning of the wafer and custom engineered image denoising post-processing. To further improve the detection sensitivity, we designed a higher precision XYZ scanning stage and replaced the laser source with an incoherent LED to remove the speckle noise. With these system modifications, we successfully detected both defects and surface contamination particles in bright-field imaging mode. Recently, we have upgraded this system for interferometric defect inspection.

  4. Polymer and Material Design for Lithography From 50 nm Node to the sub-16 nm Node

    NASA Astrophysics Data System (ADS)

    Trefonas, Peter

    2012-02-01

    Microlithography is one of the technologies which enabled the Information Age. Developing at the intersection of optical physics, polymer science and photochemistry, the need for ever smaller high fidelity patterns to build integrated circuits is currently pushing the technology evolution from 193 nm immersion lithography to extreme ultraviolet lithography (13.5 nm) to alternate patterning technologies such as directed self assembly (DSA) of block copolymers. Essential to the success of this progression is a rapid application of new concepts and materials in polymer science. We will discuss the requirements for 193 immersion lithography and how advanced acrylic random polymers are being designed with chemical amplification functionality to meet these needs. The special requirements of a water immersion lithography led to the invention and rapid commercial application of surface assembled embedded barrier layer polymers. Design of polymers for EUV lithography is having to respond to much different challenges, prominent being the dearth of photons in the exposure step, and the other being how to maximize the efficiency of photoacid production. In parallel, alternative lithographic approaches are being developed using directed self assembly of block copolymers which realize pattern frequency multiplication. We will update with our progress in the applications of polymers designed for DSA.

  5. Raman spectra from symmetric hydrogen bonds in water by high-intensity laser-induced breakdown.

    PubMed

    Men, Zhiwei; Fang, Wenhui; Li, Dongfei; Li, Zhanlong; Sun, Chenglin

    2014-01-01

    Raman spectra of ice VII and X were investigated using strong plasma shockwave generated by laser-induced breakdown (LIB) in liquid water. Simultaneously, the occurrence of the hydrogen emission lines of 656 nm (Hα), 486 nm (Hβ), 434 nm (Hγ) and 410 nm (Hδ) was observed. At 5 × 10(12) W/cm(2) optical power density, the O-H symmetric stretching, translational and librational modes of ice VII and a single peak at 785 cm(-1) appeared in the spectra. The band was assigned to the Raman-active O-O mode of the monomolecular phase, which was the symmetric hydrogen bond of cuprite ice X. The spectra indicated that ice VII and X structure were formed, as the trajectory of the strong plasma shockwave passes through the stable Pressure-Temperature range of ice VII and X. The shockwave temperature and pressure were calculated by the Grüneisen model.

  6. Raman spectra from Symmetric Hydrogen Bonds in Water by High-intensity Laser-induced Breakdown

    PubMed Central

    Men, Zhiwei; Fang, Wenhui; Li, Dongfei; Li, Zhanlong; Sun, Chenglin

    2014-01-01

    Raman spectra of ice VII and X were investigated using strong plasma shockwave generated by laser-induced breakdown (LIB) in liquid water. Simultaneously, the occurrence of the hydrogen emission lines of 656 nm (Hα), 486 nm (Hβ), 434 nm (Hγ) and 410 nm (Hδ) was observed. At 5 × 1012 W/cm2 optical power density, the O-H symmetric stretching, translational and librational modes of ice VII and a single peak at 785 cm−1 appeared in the spectra. The band was assigned to the Raman-active O-O mode of the monomolecular phase, which was the symmetric hydrogen bond of cuprite ice X. The spectra indicated that ice VII and X structure were formed, as the trajectory of the strong plasma shockwave passes through the stable Pressure-Temperature range of ice VII and X. The shockwave temperature and pressure were calculated by the Grüneisen model. PMID:24709652

  7. Leaf color is fine-tuned on the solar spectra to avoid strand direct solar radiation.

    PubMed

    Kume, Atsushi; Akitsu, Tomoko; Nasahara, Kenlo Nishida

    2016-07-01

    The spectral distributions of light absorption rates by intact leaves are notably different from the incident solar radiation spectra, for reasons that remain elusive. Incident global radiation comprises two main components; direct radiation from the direction of the sun, and diffuse radiation, which is sunlight scattered by molecules, aerosols and clouds. Both irradiance and photon flux density spectra differ between direct and diffuse radiation in their magnitude and profile. However, most research has assumed that the spectra of photosynthetically active radiation (PAR) can be averaged, without considering the radiation classes. We used paired spectroradiometers to sample direct and diffuse solar radiation, and obtained relationships between the PAR spectra and the absorption spectra of photosynthetic pigments and organs. As monomers in solvent, the spectral absorbance of Chl a decreased with the increased spectral irradiance (W m(-2) nm(-1)) of global PAR at noon (R(2) = 0.76), and was suitable to avoid strong spectral irradiance (λmax = 480 nm) rather than absorb photon flux density (μmol m(-2) s(-1) nm(-1)) efficiently. The spectral absorption of photosystems and the intact thallus and leaves decreased linearly with the increased spectral irradiance of direct PAR at noon (I dir-max), where the wavelength was within the 450-650 nm range (R(2) = 0.81). The higher-order structure of photosystems systematically avoided the strong spectral irradiance of I dir-max. However, when whole leaves were considered, leaf anatomical structure and light scattering in leaf tissues made the leaves grey bodies for PAR and enabled high PAR use efficiency. Terrestrial green plants are fine-tuned to spectral dynamics of incident solar radiation and PAR absorption is increased in various structural hierarchies. PMID:26943164

  8. Leaf color is fine-tuned on the solar spectra to avoid strand direct solar radiation.

    PubMed

    Kume, Atsushi; Akitsu, Tomoko; Nasahara, Kenlo Nishida

    2016-07-01

    The spectral distributions of light absorption rates by intact leaves are notably different from the incident solar radiation spectra, for reasons that remain elusive. Incident global radiation comprises two main components; direct radiation from the direction of the sun, and diffuse radiation, which is sunlight scattered by molecules, aerosols and clouds. Both irradiance and photon flux density spectra differ between direct and diffuse radiation in their magnitude and profile. However, most research has assumed that the spectra of photosynthetically active radiation (PAR) can be averaged, without considering the radiation classes. We used paired spectroradiometers to sample direct and diffuse solar radiation, and obtained relationships between the PAR spectra and the absorption spectra of photosynthetic pigments and organs. As monomers in solvent, the spectral absorbance of Chl a decreased with the increased spectral irradiance (W m(-2) nm(-1)) of global PAR at noon (R(2) = 0.76), and was suitable to avoid strong spectral irradiance (λmax = 480 nm) rather than absorb photon flux density (μmol m(-2) s(-1) nm(-1)) efficiently. The spectral absorption of photosystems and the intact thallus and leaves decreased linearly with the increased spectral irradiance of direct PAR at noon (I dir-max), where the wavelength was within the 450-650 nm range (R(2) = 0.81). The higher-order structure of photosystems systematically avoided the strong spectral irradiance of I dir-max. However, when whole leaves were considered, leaf anatomical structure and light scattering in leaf tissues made the leaves grey bodies for PAR and enabled high PAR use efficiency. Terrestrial green plants are fine-tuned to spectral dynamics of incident solar radiation and PAR absorption is increased in various structural hierarchies.

  9. In vivo optical characterization of human tissues from 610 to 1010 nm by time-resolved reflectance spectroscopy.

    PubMed

    Torricelli, A; Pifferi, A; Taroni, P; Giambattistelli, E; Cubeddu, R

    2001-08-01

    A fully automated system for time-resolved reflectance spectroscopy based on tunable mode-locked laser sources and on time-correlated single-photon counting for the detection of time-resolved reflectance data was applied to the evaluation of the optical properties of biological tissues (arm, abdomen and forehead) in vivo from 610 to 1010 nm. The scattering decreases progressively with increasing wavelength, while the absorption line shapes show the typical spectral features of the principal tissue components (haemoglobin, water and lipid), with different weights depending on the tissue type. The best fit of the absorption spectra measured in vivo with the spectra of the pure constituents yielded information on the percentage composition of the different tissues. The interpretation of transport scattering spectra with Mie theory provided information on tissue structure.

  10. [Application of fluorescence spectra and parallel factor analysis in the classification of edible vegetable oils].

    PubMed

    Wu, Xi-jun; Pan, Zhao; Zhao, Yan-peng; Liu, Hai-long; Zheng, Long-jiang

    2014-08-01

    The fluorescence spectra of 22 samples of 8 kinds of edible vegetable oils (soybean oil, maize oil, olive oil, rice oil, peanut oil, walnut oil, sunflower oil and sesame oil) were measured with FS920 fluorescence spectrometer and the fluorescence matrixs (EEMs) were analyzed with parallel factor (PARAFAC) analysis model. To synthesize the capabilities of material characterization and component identification, fluorescence spectra combined with PARAFAC fulfill the classification of vegetable oils. The map feature (peak position, peak value and peak number) was obtained by analyzing three dimensional spectra and con tour maps in the range of emission wavelength from 260 to 750 nm, and excitation wavelengths from 250 to 550 nm. The fluorescent substances (unsaturated fatty acids, vitamin E and its derivatives, chlorophyll and carotenoid) corresponding to spectrum peaks were determined. The factor-number was selected and the components (vitamin E and its derivatives, linoleic acid and linolenic acid, fatty acid oxidation products, vegetable oil oxidation products) corresponding to each factor were ascertained. The four-factor excitation and emission profiles and projection score plots of PARAFAC model were plotted. Different vegetable oils can be characterized and distinguished with the map features of fluorescence spectra and sample projection plots of PARAFAC model. The results demonstrate the capability of the combination of fluorescence spectra technology and four-factor PARAFAC model for differentiating and characterizing vegetable oils.

  11. Theoretical study of absorption and fluorescence spectra of firefly luciferin in aqueous solutions.

    PubMed

    Hiyama, Miyabi; Akiyama, Hidefumi; Yamada, Kenta; Koga, Nobuaki

    2012-01-01

    The absorption and fluorescence spectra of firefly luciferin, which is an analog of oxyluciferin, are investigated by performing the density functional theory (DFT) calculations, especially focusing on the experimentally unassigned peaks. Time-dependent DFT calculations are performed for the excited states of firefly luciferin and its conjugate acids and bases. We find that (1) the peaks in the experimental absorption spectra correspond to the excited states of not only (6'O(-), 4COO(-)) and (6'OH, 4COO(-)), but also (6'OH, 4COOH) and (6'OH, 3H(+), 4COOH); (2) the peaks in the experimental fluorescence spectra correspond to the excited states of not only (6'O(-), 4COO(-)), but also (6'OH, 4COO(-)), (6'O(-), 4COOH), (6'OH, 4COOH) and (6'OH, 3H(+), 4COOH); (3) the unassigned peak near 400 nm in the experimental absorption spectra at pH 1 is assigned to the absorption from the equilibrium ground state to the first excited state of (6'OH, 3H(+), 4COOH); and (4) the unassigned peak at 610 nm in the experimental fluorescence spectra corresponds to the transition from the equilibrium first excited state to the ground state of (6'OH, 4COO(-)). PMID:22364397

  12. Time-resolved EUV spectra from nitrogen Z-pinching capillary discharge

    NASA Astrophysics Data System (ADS)

    Nevrkla, Michal; Jančárek, Alexandr; Nawaz, Fahad; Parkman, Tomáś; Vrbová, Miroslava

    2015-05-01

    Time-integrated spectra and time-resolved spectra (20 ns resolution) of nitrogen discharge plasma radiation were recorded and analyzed. Plasma was created by a 70 kA, 29 ns rise-time current pulse flowing through a 5 mm inner diameter, 224 mm long capillary filled with nitrogen to initial pressure ˜0.1 ÷ 1 kPa. Spectra were captured in the wavelength range 8.3 ÷ 14 nm. This spectral region contains nitrogen Balmer series lines including potentially lasing NVII 2 - 3 transition1. Spectral lines were identified using the NIST database and the FLY kinetic code. Together with spectra the capillary current was measured. Due to the low inductance design of the driver, the pinch is observable directly from the measured current. 13.38 nm NVII 2 - 3 line was observed in gated, and also in time-integrated spectra for currents <60 kA. For higher gas-filling pressure also other Balmer series lines were observed.

  13. Fluorescence spectra of blood plasma treated with ultraviolet irradiation in vivo

    NASA Astrophysics Data System (ADS)

    Zalesskaya, G. A.; Maslova, T. O.

    2010-09-01

    We have studied the fluorescence spectra of blood plasma from patients with acute coronary syndrome, and also the effect of therapeutic doses of in vivo ultraviolet blood irradiation (UBI) on the spectra. We have established that the maxima in the fluorescence spectra of the original plasma samples, obtained from unirradiated blood, are located in the wavelength interval 330-340 nm, characteristic for the fluorescence of tryptophan residues. In extracorporeal UBI ( λ = 254 nm), we observed changes in the shape and also both a blue and a red shift in the maxima of the fluorescence spectra, differing in magnitude for blood plasma samples from different patients in the test group. We show that UBI-initiated changes in the fluorescence spectra of the plasma depend on the original pathological disturbances of metabolite levels, and also on the change in the oxygen-transport function of the blood and the acid-base balance, affecting the oxidative stability of the plasma. We have concluded that UV irradiation, activating buffer systems in the blood, has an effect on the universal and specific interactions of the tryptophan residue with the amino acid residues and water surrounding it.

  14. Two-Component Fitting of Coronal-Hole and Quiet-Sun He I 1083 Spectra

    NASA Technical Reports Server (NTRS)

    Jones, Harrison P.; Malanushenko, Elena V.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    We present reduction techniques and first results for detailed fitting of solar spectra obtained with the NASA/National Solar Observatory Spectromagnetograph (NASA/NSO SPM over a 2 nm bandpass centered on the He 1 1083 nm line. The observation for this analysis was a spectra-spectroheliogram obtained at the NSO/Kitt Peak Vacuum Telescope (KPVT) on 00 Apr 17 at 21:46 UT spanning an area of 512 x 900 arc-seconds; the field of view included a coronal hole near disk center as well as surrounding quiet sun. Since the He I line is very weak and blended with nearby solar and telluric lines, accurate determination of the continuum intensity as a function of wavelength is crucial. We have modified the technique of Malanushenko {\\it et al.) (1992; {\\it AA) (\\bf 259), 567) to tie regions of continuua and the wings of spectral lines which show little variation over the image to standard reference spectra such as the NSO Fourier Transform Spectrometer atlas (Wallace {\\it et al). 1993; NSO Tech Report \\#93-001). We performed detailed least-squares fits of spectra from selected areas, accounting for all the known telluric and solar absorbers in the spectral bandpass. The best physically consistent fits to the Helium lines were obtained with Gaussian profiles from two components (one ''cool'', characteristic of the upper chromosphere; one ''hot'', representing the cool transition region at 2-3 x 10$^{4)$ K). In the coronal hole, the transition-region component, shifted by 6-7 km/s to the blue, is mildly dominant, consistent with mass outflow as suggested by Dupree {\\it et all. (1996; {\\it Ap. J.}-{\\bf 467), 121). In quiet-sun spectra there is less evidence of outward flow, and the chromospheric component is more important. All our fitted spectra show a very weak unidentified absorption feature at 1082.880 nm in the red wing of the nearby Si I line.

  15. Manipulating Ratio Spectra for the Spectrophotometric Analysis of Diclofenac Sodium and Pantoprazole Sodium in Laboratory Mixtures and Tablet Formulation

    PubMed Central

    Bhatt, Nejal M.; Chavada, Vijay D.; Sanyal, Mallika; Shrivastav, Pranav S.

    2014-01-01

    Objective. Three sensitive, selective, and precise spectrophotometric methods based on manipulation of ratio spectra, have been developed and validated for the determination of diclofenac sodium and pantoprazole sodium. Materials and Methods. The first method is based on ratio spectra peak to peak measurement using the amplitudes at 251 and 318 nm; the second method involves the first derivative of the ratio spectra (Δλ = 4 nm) using the peak amplitudes at 326.0 nm for diclofenac sodium and 337.0 nm for pantoprazole sodium. The third is the method of mean centering of ratio spectra using the values at 318.0 nm for both the analytes. Results. All the three methods were linear over the concentration range of 2.0–24.0 μg/mL for diclofenac sodium and 2.0–20.0 μg/mL for pantoprazole sodium. The methods were validated according to the ICH guidelines and accuracy, precision, repeatability, and robustness are found to be within the acceptable limit. The results of single factor ANOVA analysis indicated that there is no significant difference among the developed methods. Conclusions. The developed methods provided simple resolution of this binary combination from laboratory mixtures and pharmaceutical preparations and can be conveniently adopted for routine quality control analysis. PMID:24701171

  16. Trion spectra of semiconductor nanostructures

    NASA Astrophysics Data System (ADS)

    Esser, Axel; Runge, Erich; Zimmermann, Roland

    2001-03-01

    The linear optical properties of quantum wells and quantum wires in the presence of a moderate background carrier density nB are investigated theoretically and compared with recent experiments. At low n_B, excitons and trions (charged excitons) are the relevant excitations. We present a density-matrix approach, which starts from the interband polarization and couples directly to higher order correlation functions which are related to three-particle excitations. It allows to describe both trionic and excitonic states. A generalized dynamical truncation scheme is applied and yields an expression for the absorption coefficient of trions in terms of trion eigenstates. Then, in combination with a numerical solution of the three-particle Schrödinger equation we sucessfully model (i) experimental photoluminescence lineshapes (their asymmetry towards lower photon energy and temperature-dependence is related to carrier recoil) [1], (ii) radiative trion lifetime (shown to depend linearly on temperature for a thermalized trion distribution) [2], and (iii) the influence of an electrical field (quantum-confined Stark effect) [3]. The optical response of excitons and trions can be studied alternatively by the solution of the time-dependent trion Schrödinger equation yielding information about (i) the appearance of trion triplet states (shown to be optically inactice at vanishing center-of-mass momentum), and (ii) exciton-electron scattering states (which give rise to a broadening of the high-energy side of the exciton). Altogether, a consistent and thorough picture of exciton related absorption spectra in the presence of additional carriers can be derived either from density matrix theory or the solution of the time-dependent three-particle Schrödinger equation. [1] A. Esser et al., Phys. Rev. B 62, 8232 (2000); [2] V. Ciulin et al., Phys. Rev. B (2000); [3] A. Esser et al., Phys. Status Solidi B 221, 281 (2000).

  17. Incorporating Spectra Into Periodic Timing

    NASA Astrophysics Data System (ADS)

    Connors, Alanna; Hong, J.; Protopapas, P.; Kashyap, V.

    2011-09-01

    The Chandra surveys have resulted in a wealth of data on low-luminosity X-ray sources (Lx 1030-34 erg/s) of Galactic scales beyond the local solar neighborhood. Many of these are compact binaries, in particular, cataclysmic variables, often identified by their periodic X-ray variability and spectra. Hong et al. (2009, 2011) have used energy quantiles (Hong, Schlegel & Grindlay, 2004) as a fast, robust indicator of spectral hardness and absorption of the X-ray sources. Energy quantiles also enable a simple but effective illustration of spectral changes with phase in these periodic systems: e.g. absorption by the accreting material is understood to drive the periodic light-curves. An interesting question is how to best make use of the information encapsulated in the periodic change in energy spectrum, along with the periodic change in intensity, especially for cases of ambiguous period determination? And, how to do it computationally efficiently? A first approach is to do the period search in intensity, as is standard; and then use a criterion of spectral variation to verify possible periods. Huijse, Zegers & Protopapas (2011) recently demonstrated a powerful period estimation technique using information potential and correntropy embedded in the light curve. Similar quantities based on energies (or energy quantiles) of X-ray photons can serve as criteria of spectral variation. A different approach treats the spectrum variations and intensity variations completely independently, searching through period-space in each, and then combining the results. A more general method would include both at the same time, looking for statistically significant variations above what is expected for a constant (in intensity and spectrum).

  18. Electronic absorption spectra of linear and cyclic Cn+ n=7-9 in a neon matrix

    NASA Astrophysics Data System (ADS)

    Fulara, Jan; Shnitko, Ivan; Batalov, Anton; Maier, John P.

    2005-07-01

    The Cn+n=7-9 cations were produced by electron-impact ionization of perchloronaphthalene, mass selected, and their electronic absorption spectra in 6K neon matrices recorded. The linear and cyclic isomers of C7+ and C8+ are detected. Three systems of linear C7+ are observed with origin bands near 770, 332, and 309nm. The cyclic C7+ shows two transitions near 676 and 448nm. One system of linear C9+ is observed commencing at 371nm. Linear C8+ shows five dipole-allowed electronic transitions from the X˜Πg2 ground state, and the strongest ones have the origin bands at 890.8 and 308.1nm. Five electronic transitions of cyclic C8+ are also discernible.

  19. Comparison between HMME mediated photodynamic therapy using 413nm and 532nm for port wine stains: a mathematical simulation study

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Gu, Y.; Chen, R.; Xu, L. Q.; Liao, X. H.; Huang, N. Y.; Wang, Y. Y.

    2007-11-01

    Introduction: As it is always difficult to find the optimal combination of photosensitizer and of laser wavelength to achieve selective vascular damage in PWS-PDT, the selective vascular effects of HMME (Hematoporphyrin monomethyl ether) mediated PDT with 413 nm and with 532 nm were compared by mathematical simulation in this study. Materials & Methods: Firstly, distribution of 413 nm, 532 nm light in PWS tissue was simulated by Monte Carlo model. Two energy density groups were set, one is 80mW/cm2x40min for both 413 nm and 532 nm, the other is 80mW/cm2x40min for 532 nm while 80mW/cm2x20min in for 413 nm. Secondly, the productivity of reactive oxygen species (ROS) in target vessels and normal tissue were simulated using a simulation system for PDT of PWS established in our lab, which considering the amount of light and photosensitizer in tissue, the molar extinction coefficient of photosensitizer, and quantum yield of ROS. Concentration of HMME for each wavelength were same. Finally, the productivity of ROS n in target vessels and normal tissue were compared between 413 nm PDT and 532 nm PDT under different energy density. Result: Under the same energy density, ROS productivity in target vessels of 413 nm PDT was significantly higher than that of 532 nm PDT. Moreover, it was still higher at low energy density than that of 532nm PDT with high energy density. Conclusion: HMME mediated PDT using 413 nm has the potential to increase the selective vascular effect of PDT for PWS by shortening treatment time.

  20. Non-Destructive Observation of the Laser Treatment Effect on Historical Paper via the Laser-Induced Fluorescence Spectra

    NASA Astrophysics Data System (ADS)

    Komar, K.; Sliwinski, G.

    The fluorescence spectra of historical and model paper samples, previously irradiated with the laser beam at wavelengths of 1,064, 532, 355, and 266 nm, are recorded under excitation at 266 nm, and the nonirradiated samples are used for reference. The spectral profiles obtained for the laser-treated model papers made of cotton and/or linen only reveal differences compared to the reference ones. After irradiation at 532 and 1,064 nm, a decrease of the band intensities of the entire spectral profile is observed. In contrary, the UV irradiation at 355nm of the same samples results in the increase of bands centered at 341 and 370nm compared to the visible region only. Prolonged treatment at 266nm results in the marked increase of band intensities in the visible region and corresponds to the independently observed yellowing.

  1. LINE PARAMETERS OF THE 782 nm BAND OF CO{sub 2}

    SciTech Connect

    Lu, Y.; Liu, A.-W.; Li, X.-F.; Wang, J.; Cheng, C.-F.; Sun, Y. R.; Lambo, R.; Hu, S.-M.

    2013-09-20

    The 782 nm band of CO{sub 2}, in a transparent window of Earth's atmosphere, was the first CO{sub 2} band observed 80 yr ago in the spectra of Venus. The band is very weak and therefore not saturated by the thick atmosphere of Venus, but its spectral parameters are still very limited due to the difficulty of detecting it in the laboratory. It is the highest overtone (ν{sub 1} + 5ν{sub 3}) of CO{sub 2} given in widely used spectroscopy databases such as HITRAN and GEISA. In the present work, the band is studied using a cavity ring-down spectrometer with ultra-high sensitivity as well as high precision. The positions of 55 lines in the band were determined with an absolute accuracy of 3 × 10{sup –5} cm{sup –1}, two orders of magnitude better than previous studies. The line intensities, self-induced pressure broadening coefficients, and the shift coefficients were also derived from the recorded spectra. The obtained spectral parameters can be applied to model the spectra of the CO{sub 2}-rich atmospheres of planets like Venus and Mars.

  2. 9nm node wafer defect inspection using visible light

    NASA Astrophysics Data System (ADS)

    Zhou, Renjie; Edwards, Chris; Popescu, Gabriel; Goddard, Lynford L.

    2014-04-01

    Over the past 2 years, we have developed a common optical-path, 532 nm laser epi-illumination diffraction phase microscope (epi-DPM) and successfully applied it to detect different types of defects down to 20 by 100 nm in a 22nm node intentional defect array (IDA) wafer. An image post-processing method called 2DISC, using image frame 2nd order differential, image stitching, and convolution, was used to significantly improve sensitivity of the measured images. To address 9nm node IDA wafer inspection, we updated our system with a highly stable 405 nm diode laser. By using the 2DISC method, we detected parallel bridge defects in the 9nm node wafer. To further enhance detectability, we are exploring 3D wafer scanning, white-light illumination, and dark-field inspection.

  3. Optical transmission and Faraday rotation spectra of a bismuth iron garnet film

    NASA Astrophysics Data System (ADS)

    Kahl, S.; Popov, V.; Grishin, A. M.

    2003-11-01

    We prepared an epitaxial 530-nm-thick bismuth iron garnet (BIG) film on a Gd3Ga5O12(GGG) (111) substrate by pulsed laser deposition and measured spectra of optical transmission and magneto-optical Faraday rotation θF(λ) in visible light. Both spectra are shaped by the dispersion relations of the dielectric tensor and the effects of multiple-beam interference in the thin film. From fitting of the transmission spectrum, dispersion relations of the real and imaginary parts of the refractive index were found for the wavelength range from 515 to 1000 nm, n(λ)=2.36+(413 nm/λ)2 and k(λ)=(λ/4π nm)×exp[(1660 nm/λ)2-15.2]. With these data as input information, a single diamagnetic line centered at λ=486 nm was fitted to the experimentally recorded magneto-optical spectrum. The effects of thin film interference and surface roughness were included in order to closely reproduce the measured spectrum. The roughness determined from spectral analysis was compared to the rms roughness measured by atomic force microscopy. The values agree within a deviation of less than 20% and are approximately 3% of film thickness. The magneto-optical figure of merit 2|θF|/α (α is the absorption coefficient) of our film increases strongly with wavelength and exceeds 100° at 740 nm. The optical efficiency for magneto-optical visualization |exp(-2αd)sin(4θFd)| (d is film thickness) possesses a maximum value of 29% at 600 nm. Both quantities were calculated using the obtained dispersion relations for absorption and Faraday rotation.

  4. Segmentation of the macular choroid in OCT images acquired at 830nm and 1060nm

    NASA Astrophysics Data System (ADS)

    Lee, Sieun; Beg, Mirza F.; Sarunic, Marinko V.

    2013-06-01

    Retinal imaging with optical coherence tomography (OCT) has rapidly advanced in ophthalmic applications with the broad availability of Fourier domain (FD) technology in commercial systems. The high sensitivity afforded by FD-OCT has enabled imaging of the choroid, a layer of blood vessels serving the outer retina. Improved visualization of the choroid and the choroid-sclera boundary has been investigated using techniques such as enhanced depth imaging (EDI), and also with OCT systems operating in the 1060-nm wavelength range. We report on a comparison of imaging the macular choroid with commercial and prototype OCT systems, and present automated 3D segmentation of the choroid-scleral layer using a graph cut algorithm. The thickness of the choroid is an important measurement to investigate for possible correlation with severity, or possibly early diagnosis, of diseases such as age-related macular degeneration.

  5. Faster optical-spectra recording and analysis

    NASA Technical Reports Server (NTRS)

    Richmond, R. G.

    1977-01-01

    Optical spectra are recorded and rapidly analyzed by system that links multichannel analyzer and desk-top programable calculator. Cassette-memory storage is provided. System can be programed to automate background subtraction, axis expansion, and other data-analysis techniques and can store several hundred spectra for immediate or delayed analysis and comparisons.

  6. (abstract) Spectra of Comet Hale-Bopp

    NASA Technical Reports Server (NTRS)

    Hanner, M. S.; Hayward, T. L.; Lynch, D. K.; Russell, R. W.

    1996-01-01

    The spectra of Hale-Bopp were acquired in mid-1996 at R > 3.5 AU. Strong silicate emission is present in all the spectra. The shape of the feature is very similar to that seen in comet P/Halley. This is the first time that a strong silicate feature has been detected in a comet beyond 2 AU.

  7. Quantitative photoabsorption and fluorescence spectroscopy of H2S and D2S at 49-240 nm

    NASA Technical Reports Server (NTRS)

    Lee, L. C.; Wang, Xiuyan; Suto, Masako

    1987-01-01

    Photoabsorption and fluorescence cross sections of H2S and D2S were measured in the 49-240 nm region using synchrotron radiation as a light source. Fluorescence from photoexcitation of H2S appears at 49-97 nm, but not in the long wavelength region. Fluorescence spectra were dispersed, and used to identify the emitters to be H2S(+) (A), SH(+)(A), and H(n greater than 2). The fluorescence quantum yield is about 6 percent. Photoexcitation of D2S at 49-96 nm produces fluorescence with a quantum yield of about 5 percent. The emitters are identified from the fluorescence spectra to be D2S(+)(A), SD(+)(A), and D(n greater than 2). The Franck-Condon factors for the SH(+) and SD(+) (A-X) transitions were determined. The SD(A-X) fluorescence was observed from photoexcitation of D2S at 100-151 nm, for which the fluorescence cross section and quantum yield were measured.

  8. Detection limits of 405 nm and 633 nm excited PpIX fluorescence for brain tumor detection during stereotactic biopsy

    NASA Astrophysics Data System (ADS)

    Markwardt, Niklas; Götz, Marcus; Haj-Hosseini, Neda; Hollnburger, Bastian; Sroka, Ronald; Stepp, Herbert; Zelenkov, Petr; Rühm, Adrian

    2016-04-01

    5-aminolevulinic-acid-(5-ALA)-induced protoporphyrin IX (PpIX) fluorescence may be used to improve stereotactic brain tumor biopsies. In this study, the sensitivity of PpIX-based tumor detection has been investigated for two potential excitation wavelengths (405 nm, 633 nm). Using a 200 μm fiber in contact with semi-infinite optical phantoms containing ink and Lipovenös, PpIX detection limits of 4.0 nM and 200 nM (relating to 1 mW excitation power) were determined for 405 nm and 633 nm excitation, respectively. Hence, typical PpIX concentrations in glioblastomas of a few μM should be well detectable with both wavelengths. Additionally, blood layers of selected thicknesses were placed between fiber and phantom. Red excitation was shown to be considerably less affected by blood interference: A 50 μm blood layer, for instance, blocked the 405- nm-excited fluorescence completely, but reduced the 633-nm-excited signal by less than 50%. Ray tracing simulations demonstrated that - without blood layer - the sensitivity advantage of 405 nm rises for decreasing fluorescent volume from 50-fold to a maximum of 100-fold. However, at a tumor volume of 1 mm3, which is a typical biopsy sample size, the 633-nm-excited fluorescence signal is only reduced by about 10%. Further simulations revealed that with increasing fiber-tumor distance, the signal drops faster for 405 nm. This reduces the risk of detecting tumor tissue outside the needle's coverage, but diminishes the overlap between optically and mechanically sampled volumes. While 405 nm generally offers a higher sensitivity, 633 nm is more sensitive to distant tumors and considerably superior in case of blood-covered tumor tissue.

  9. Isotope shifts in spectra of molecular liquids

    NASA Astrophysics Data System (ADS)

    Dubrovskaya, E. V.; Kolomiitsova, T. D.; Shurukhina, A. V.; Shchepkin, D. N.

    2016-02-01

    In the IR absorption spectra of low-temperature molecular liquids, we have observed anomalously large isotope shifts of frequencies of vibrational bands that are strong in the dipole absorption. The same effect has also been observed in their Raman spectra. At the same time, in the spectra of cryosolutions, the isotope shifts of the same bands coincide with a high accuracy (±(0.1-0.5) cm-1) with the shifts that are observed in the spectra of the gas phase. The difference between the spectra of examined low-temperature systems is caused by the occurrence of resonant dipole-dipole interactions between spectrally active identical molecules. The calculation of the band contour in the spectrum of liquid freon that we have performed in this work taking into account the resonant interaction between states of simultaneous transitions in isotopically substituted molecules can explain this effect.

  10. PCA: Principal Component Analysis for spectra modeling

    NASA Astrophysics Data System (ADS)

    Hurley, Peter D.; Oliver, Seb; Farrah, Duncan; Wang, Lingyu; Efstathiou, Andreas

    2012-07-01

    The mid-infrared spectra of ultraluminous infrared galaxies (ULIRGs) contain a variety of spectral features that can be used as diagnostics to characterize the spectra. However, such diagnostics are biased by our prior prejudices on the origin of the features. Moreover, by using only part of the spectrum they do not utilize the full information content of the spectra. Blind statistical techniques such as principal component analysis (PCA) consider the whole spectrum, find correlated features and separate them out into distinct components. This code, written in IDL, classifies principal components of IRS spectra to define a new classification scheme using 5D Gaussian mixtures modelling. The five PCs and average spectra for the four classifications to classify objects are made available with the code.

  11. Blind extraction of exoplanetary spectra

    NASA Astrophysics Data System (ADS)

    Morello, Giuseppe; Waldmann, Ingo; Damiano, Mario; Tinetti, Giovanna

    2016-10-01

    In the last decade, remote sensing spectroscopy enabled characterization of the atmospheres of extrasolar planets. Transmission and emission spectra of tens of transiting exoplanets have been measured with multiple instruments aboard Spitzer and Hubble Space Telescopes as well as ground-based facilities, revealing the presence of chemical species in their atmospheres, and constraining their temperature and pressure profiles.Early analyses were somehow heuristic, leading to some controversies in the literature.A photometric precision of 0.01% is necessary to detect the atmospheric spectral modulations. Current observatories, except Kepler, were not designed to achieve this precision. Data reduction is necessary to minimize the effect of instrument systematics in order to achieve the target precision. In the past, parametric models have extensively been used by most teams to remove correlated noise with the aid of auxiliary information of the instrument, the so-called optical state vectors (OSVs). Such OSVs can include inter- and intra-pixel position of the star or its spectrum, instrument temperatures and inclinations, and/or other parameters. In some cases, different parameterizations led to discrepant results.We recommend the use of blind non-parametric data detrending techniques to overcome those issues. In particular, we adopt Independent Component Analysis (ICA), i.e. a powerful blind source separation (BSS) technique to disentangle the multiple instrument systematics and astrophysical signals in transit/eclipse light curves. ICA does not require a model for the systematics, thence it can be applied to any instrument with little changes, if any. ICA-based algorithms have been applied to Spitzer/IRAC and synthetic observations in photometry (Morello et al. 2014, 2015, 2016; Morello 2015) and to Hubble/WFC3, Hubble/NICMOS and Spitzer/IRS and Hubble/WFC3 in spectroscopy (Damiano, Morello et al., in prep., Waldmann 2012, 2014, Waldmann et al. 2013) with excellent

  12. 7nm logic optical lithography with OPC-Lite

    NASA Astrophysics Data System (ADS)

    Smayling, Michael C.; Tsujita, Koichiro; Yaegashi, Hidetami; Axelrad, Valery; Nakayama, Ryo; Oyama, Kenichi; Yamauchi, Shohei; Ishii, Hiroyuki; Mikami, Koji

    2015-03-01

    The CMOS logic 22nm node was the last one done with single patterning. It used a highly regular layout style with Gridded Design Rules (GDR). Smaller nodes have required the same regular layout style but with multiple patterning for critical layers. A "line/cut" approach is being used to achieve good pattern fidelity and process margin.[1] As shown in Fig. 1, even with "line" patterns, pitch division will eventually be necessary. For the "cut" pattern, Design-Source-Mask Optimization (DSMO) has been demonstrated to be effective at the 20nm node and below.[2,3,4] Single patterning was found to be suitable down to 16nm, while double patterning extended optical lithography for cuts to the 10-12nm nodes. Design optimization avoided the need for triple patterning. Lines can be patterned with 193nm immersion with no complex OPC. The final line dimensions can be achieved by applying pitch division by two or four.[5] In this study, we extend the scaling using simplified OPC to the 7nm node for critical FEOL and BEOL layers. The test block is a reasonably complex logic function with ~100k gates of combinatorial logic and flip-flops, scaled from previous experiments. Simulation results show that for cuts at 7nm logic dimensions, the gate layer can be done with single patterning whose minimum pitch is 53nm, possibly some of the 1x metal layers can be done with double patterning whose minimum pitch is 53nm, and the contact layer will require triple patterning whose minimum pitch is 68nm. These pitches are less than the resolution limit of ArF NA=1.35 (72nm). However these patterns can be separated by a combination of innovative SMO for less than optical resolution limit and a process trick of hole-repair technique. An example of triple patterning coloring is shown in Fig 3. Fin and local interconnect are created by lines and trims. The number of trim patterns are 3 times (min. pitch=90nm) and twice (min. pitch=120nm), respectively. The small number of masks, large pitches, and

  13. Pulsed blue laser at 491 nm by nonlinear cavity dumping.

    PubMed

    Herault, Emilie; Lelek, Mickaël; Balembois, François; Georges, Patrick

    2008-11-24

    A nonlinear cavity dumping process is applied for the first time to generate kW peak power pulses at 491 nm. The system is based on efficient sum-frequency mixing of 1063 nm and 912 nm radiations in a BiBO nonlinear crystal placed inside a Nd:GdVO4 laser oscillator with a high finesse cavity at 912 nm. The nonlinear cavity dumping process is triggered by high peak power nanosecond pulses from a 1063 nm Q-switched Nd:GdVO4 laser operating at 10 kHz. To reach the kW range at 491 nm a key point is to Q-switch the high finesse 912 nm cavity instead of continuous wave operation. Thus, the peak power (9.3 kW for 3 ns pulses) and the average power (280 mW) obtained at 491 nm are 14 times higher than the one obtained when the 912 nm laser operated in continuous wave. PMID:19030029

  14. 40nm tunable multi-wavelength fiber laser

    NASA Astrophysics Data System (ADS)

    Jia, Qingsong; Wang, Tianshu; Zhang, Peng; Dong, Keyan; Jiang, Huilin

    2014-12-01

    A Brillouin-Erbium multi-wavelength tunable fiber laser at C-band is demostrated. A 10 km long singlemode fiber(SMF), a 6 m long Erbium-doped fiber, two couplers, a wavelength division multiplexer, a isolator, an optical circulator, a 980nm pump laser and a narrow linewidth tunable laser are included in the structure. A segment of 10 km-long single-mode fiber (SMF) between the two ports of a 1×2 coupler is used as Brillouin gain. Ebiumdoped fiber amplifier (EDFA) consists of a segment of 6m er-doped fiber pumped by 980nm laser dioder . A narrow linewidth tunable laser from 1527 to 1607 nm as Brillouin bump, At the Brillouin pump power of 8mW and the 980 nm pump power of 400 mw, 16 output channels with 0.08 nm spacing and tuning range of 40 nm from 1527 nm to 1567 nm are achieved. We realize the tunable output of wavelength by adjusting the 980 nm pump power and the Brillouin pump wavelength. Stability of the multiwavelength fiber laser is also observed.

  15. Generation and use of high power 213 nm and 266 nm laser radiation and tunable 210-400 nm laser radiation with BBO crystal matrix array

    DOEpatents

    Gruen, Dieter M.

    2000-01-01

    A 213 nm laser beam is capable of single photon ablative photodecomposition for the removal of a polymer or biological material substrate. Breaking the molecular bonds and displacing the molecules away from the substrate in a very short time period results in most of the laser photon energy being carried away by the displaced molecules, thus minimizing thermal damage to the substrate. The incident laser beam may be unfocussed and is preferably produced by quintupling the 1064 nm radiation from a Nd:YAG solid state laser, i.e., at 213 nm. In one application, the 213 nm laser beam is expanded in cross section and directed through a plurality of small beta barium borate (BBO) crystals for increasing the energy per photon of the laser radiation directed onto the substrate. The BBO crystals are arranged in a crystal matrix array to provide a large laser beam transmission area capable of accommodating high energy laser radiation without damaging the BBO crystals. The BBO crystal matrix array may also be used with 266 nm laser radiation for carrying out single or multi photon ablative photodecomposition. The BBO crystal matrix array may also be used in an optical parametric oscillator mode to generate high power tunable laser radiation in the range of 210-400 nm.

  16. Development of normalized spectra manipulating spectrophotometric methods for simultaneous determination of Dimenhydrinate and Cinnarizine binary mixture.

    PubMed

    Lamie, Nesrine T; Yehia, Ali M

    2015-01-01

    Simultaneous determination of Dimenhydrinate (DIM) and Cinnarizine (CIN) binary mixture with simple procedures were applied. Three ratio manipulating spectrophotometric methods were proposed. Normalized spectrum was utilized as a divisor for simultaneous determination of both drugs with minimum manipulation steps. The proposed methods were simultaneous constant center (SCC), simultaneous derivative ratio spectrophotometry (S(1)DD) and ratio H-point standard addition method (RHPSAM). Peak amplitudes at isoabsorptive point in ratio spectra were measured for determination of total concentrations of DIM and CIN. For subsequent determination of DIM concentration, difference between peak amplitudes at 250 nm and 267 nm were used in SCC. While the peak amplitude at 275 nm of the first derivative ratio spectra were used in S(1)DD; then subtraction of DIM concentration from the total one provided the CIN concentration. The last RHPSAM was a dual wavelength method in which two calibrations were plotted at 220 nm and 230 nm. The coordinates of intersection point between the two calibration lines were corresponding to DIM and CIN concentrations. The proposed methods were successfully applied for combined dosage form analysis, Moreover statistical comparison between the proposed and reported spectrophotometric methods was applied. PMID:26037499

  17. Assessment and mapping of soil nitrogen using Visible-Near-Infrared (Vis-NIR) spectra

    NASA Astrophysics Data System (ADS)

    Liu, Xiang; Guo, Yan; Wang, Qian-long; Zhang, Jian; Shi, Zhou

    2013-08-01

    Visible and near infrared (Vis-NIR) reflectance spectroscopy technology, which is rapid, cost-effective, in-situ and non-destructive, is getting more and more widely used in improving the prediction and digital mapping for soil properties. Soil available nitrogen (AN) is closely related to soil fertility and quality, assessing its content and mapping the spatial variability greatly satisfies precision agriculture. In this study, the Vis-NIR diffuse reflectance spectra collected by ASD FieldSpec Pro FR spectrometer with a performance of spectral range from 350 nm to 2500 nm, 1 nm resampling intervals, was used to model and characterize the spatial variability of available nitrogen. Firstly, the raw soil spectra was pre-processing by reducing to 400 nm - 2450 nm with transformation into apparent absorbance spectral using Log(1/R) and Savitzky-Golay smoothing. Secondly, spectral indices (normalized spectral index-NDI; difference index-DI; ratio index-RI) were convinced for seeking further relationship between AN. Afterwards, Partial Least Squares Regression (PLSR) method was employed to predict AN. The results indicated good predictions with RPD more than 1.4. Finally, the spatial variability of AN was mapped by (co)kriging method, digital mapping of the measured and predicted AN showed similar patterns and value ranges, though there are some minor differences. The resultant prediction and mapping demonstrated a promotion of assessing and mapping of soil properties by a rapid and reliable approach from lab to field in-situ.

  18. Investigation of absorption spectra of Gafchromic EBT2 film's components and their impact on UVR dosimetry

    NASA Astrophysics Data System (ADS)

    Aydarous, Abdulkadir

    2016-05-01

    The absorption spectra of the EBT2 film's components were investigated in conjunction with its use for UVA dosimetry. The polyester (topside) and adhesive layers of the EBT2 film have been gently removed. Gafchromic™ EBT2 films with and without the protected layers (polyester and adhesive) were exposed to UVR of 365 nm for different durations. Thereafter, the UV-visible spectra were measured using a UV-visible spectrophotometer (Model Spectro Dual Split Beam, UVS-2700). Films were digitized using a Nikon CanoScan 9000F Mark II flatbed scanner. The dosimetric characteristics including film's uniformity, reproducibility and post-irradiation development were investigated. The color development of EBT2 and new modified EBT2 (EBT2-M) films irradiated with UVA was relatively stable (less than 1%) immediately after exposure. Based on this study, the sensitivity of EBT2 to UVR with wavelength between ~350 nm and ~390 nm can significantly be enhanced if the adhesive layer (~25 μm) is removed. The polyester layer plays almost no part on absorbing UVR with wavelength between ~320 nm and ~390 nm. Furthermore, various sensitivities for the EBT2-M film has been established depending on the wavelength of analysis.

  19. Excitation-emission spectra and fluorescence quantum yields for fresh and aged biogenic secondary organic aerosols

    SciTech Connect

    Lee, Hyun Ji; Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey A.

    2013-05-10

    Certain biogenic secondary organic aerosols (SOA) become absorbent and fluorescent when exposed to reduced nitrogen compounds such as ammonia, amines and their salts. Fluorescent SOA may potentially be mistaken for biological particles by detection methods relying on fluorescence. This work quantifies the spectral distribution and effective quantum yields of fluorescence of SOA generated from two monoterpenes, limonene and a-pinene, and two different oxidants, ozone (O3) and hydroxyl radical (OH). The SOA was generated in a smog chamber, collected on substrates, and aged by exposure to ~100 ppb ammonia vapor in air saturated with water vapor. Absorption and excitation-emission matrix (EEM) spectra of aqueous extracts of aged and control SOA samples were measured, and the effective absorption coefficients and fluorescence quantum yields (~0.005 for 349 nm excitation) were determined from the data. The strongest fluorescence for the limonene-derived SOA was observed for excitation = 420+- 50 nm and emission = 475 +- 38 nm. The window of the strongest fluorescence shifted to excitation = 320 +- 25 nm and emission = 425 +- 38 nm for the a-pinene-derived SOA. Both regions overlap with the excitation-emission matrix (EEM) spectra of some of the fluorophores found in primary biological aerosols. Our study suggests that, despite the low quantum yield, the aged SOA particles should have sufficient fluorescence intensities to interfere with the fluorescence detection of common bioaerosols.

  20. [Study on three-dimensional fluorescence spectra of Yanghe classical distilled spirits].

    PubMed

    Gu, En-dong; Shi, Ai-min; Zhu, Tuo; Xu, Yan; Chen, Guo-qing

    2008-12-01

    In the present paper, the liquors of Hai zhi lan, Tian zhi lan and Meng zhi lan were selected as the objects, and by using equipment of UV-240 ultra-violet spectrophotometer and Sp-2558 multifunctional spectrometer, their absorption and three-dimensional fluorescence spectra induced by UV light were studied respectively. The maximum absorption wavelengths for all of them were located at 212 and 275 nm, but each has different intensity at 212 nm. Moreover, their three-dimensional fluorescence spectra were detected when they were induced by suitable UV-light, The results show that each of the spirits can emit three strong fluorescence lines at 310, 420 and 610 nm respectively when excited by UV-light at 245 nm. Furthermore, we found each of them can emit another two strong fluorescence lines when they absorb the UV-light at 310 and 345 nm. The authors found that they all have five different fluorescence peaks, but each has different intensity. According to the experimental phenomenon, through a careful analysis, it is pointed out that the differences of the five fluorescence peaks basically reflect the aging process and different content of the liquor. The three different brand yanghe classical liquors were identified fast and accurately. The paper also offered a kind of way to determine the quality and brand of white spirit.

  1. Excitation-emission spectra and fluorescence quantum yields for fresh and aged biogenic secondary organic aerosols.

    PubMed

    Lee, Hyun Ji Julie; Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey A

    2013-06-01

    Certain biogenic secondary organic aerosols (SOA) become absorbent and fluorescent when exposed to reduced nitrogen compounds such as ammonia, amines, and their salts. Fluorescent SOA may potentially be mistaken for biological particles by detection methods relying on fluorescence. This work quantifies the spectral distribution and effective quantum yields of fluorescence of water-soluble SOA generated from two monoterpenes, limonene and α-pinene, and two different oxidants, ozone (O3) and hydroxyl radical (OH). The SOA was generated in a smog chamber, collected on substrates, and aged by exposure to ∼100 ppb ammonia in air saturated with water vapor. Absorption and excitation-emission matrix (EEM) spectra of aqueous extracts of aged and control SOA samples were measured, and the effective absorption coefficients and fluorescence quantum yields (∼0.005 for 349 nm excitation) were determined from the data. The strongest fluorescence for the limonene-derived SOA was observed for λexcitation = 420 ± 50 nm and λemission = 475 ± 38 nm. The window of the strongest fluorescence shifted to λexcitation = 320 ± 25 nm and λemission = 425 ± 38 nm for the α-pinene-derived SOA. Both regions overlap with the EEM spectra of some of the fluorophores found in primary biological aerosols. Despite the low quantum yield, the aged SOA particles may have sufficient fluorescence intensities to interfere with the fluorescence detection of common bioaerosols.

  2. The effect of the operation modes of a gas discharge low-pressure amalgam lamp on the intensity of generation of 185 nm UV vacuum radiation

    SciTech Connect

    Vasilyak, L. M.; Drozdov, L. A. Kostyuchenko, S. V.; Sokolov, D. V.; Kudryavtsev, N. N.; Sobur, D. A.

    2011-12-15

    The effect of the discharge current, mercury vapor pressure, and the inert gas pressure on the intensity and efficiency of the 185 nm line generation are considered. The spectra of the UV radiation (vacuum ultraviolet) transmission by protective coatings from the oxides of rare earth metals and aluminum are investigated.

  3. Spatially and momentum resolved energy electron loss spectra from an ultra-thin PrNiO{sub 3} layer

    SciTech Connect

    Kinyanjui, M. K. Kaiser, U.; Benner, G.; Pavia, G.; Boucher, F.; Habermeier, H.-U.; Keimer, B.

    2015-05-18

    We present an experimental approach which allows for the acquisition of spectra from ultra-thin films at high spatial, momentum, and energy resolutions. Spatially and momentum (q) resolved electron energy loss spectra have been obtained from a 12 nm ultra-thin PrNiO{sub 3} layer using a nano-beam electron diffraction based approach which enabled the acquisition of momentum resolved spectra from individual, differently oriented nano-domains and at different positions of the PrNiO{sub 3} thin layer. The spatial and wavelength dependence of the spectral excitations are obtained and characterized after the analysis of the experimental spectra using calculated dielectric and energy loss functions. The presented approach makes a contribution towards obtaining momentum-resolved spectra from nanostructures, thin film, heterostructures, surfaces, and interfaces.

  4. Absorption spectra of adenocarcinoma and squamous cell carcinoma cervical tissues

    NASA Astrophysics Data System (ADS)

    Ivashko, Pavlo; Peresunko, Olexander; Zelinska, Natalia; Alonova, Marina

    2014-08-01

    We studied a methods of assessment of a connective tissue of cervix in terms of specific volume of fibrous component and an optical density of staining of connective tissue fibers in the stroma of squamous cancer and cervix adenocarcinoma. An absorption spectra of blood plasma of the patients suffering from squamous cancer and cervix adenocarcinoma both before the surgery and in postsurgical periods were obtained. Linear dichroism measurements transmittance in polarized light at different orientations of the polarization plane relative to the direction of the dominant orientation in the structure of the sample of biotissues of stroma of squamous cancer and cervix adenocarcinoma were carried. Results of the investigation of the tumor tissues showed that the magnitude of the linear dichroism Δ is insignificant in the researched spectral range λ=280-840 nm and specific regularities in its change observed short-wave ranges.

  5. Single particle size and fluorescence spectra from emissions of burning materials in a tube furnace to simulate burn pits

    NASA Astrophysics Data System (ADS)

    Pan, Yong-Le; Houck, Joshua D. T.; Clark, Pamela A.; Pinnick, Ronald G.

    2013-08-01

    A single-particle fluorescence spectrometer (SPFS) and an aerodynamic particle sizer were used to measure the fluorescence spectra and particle size distribution from the particulate emissions of 12 different burning materials in a tube furnace to simulate open-air burning of garbage. Although the particulate emissions are likely dominated by particles <1 μm diameter, only the spectra of supermicron particles were measured here. The overall fluorescence spectral profiles exhibit either one or two broad bands peaked around 300-450 nm within the 280-650 nm spectral range, when the particles are illuminated with a 263-nm laser. Different burning materials have different profiles, some of them (cigarette, hair, uniform, paper, and plastics) show small changes during the burning process, and while others (beef, bread, carrot, Styrofoam, and wood) show big variations, which initially exhibit a single UV peak (around 310-340 nm) and a long shoulder in visible, and then gradually evolve into a bimodal spectrum with another visible peak (around 430-450 nm) having increasing intensity during the burning process. These spectral profiles could mainly derive from polycyclic aromatic hydrocarbons with the combinations of tyrosine-like, tryptophan-like, and other humic-like substances. About 68 % of these single-particle fluorescence spectra can be grouped into 10 clustered spectral templates that are derived from the spectra of millions of atmospheric aerosol particles observed in three locations; while the others, particularly these bimodal spectra, do not fall into any of the 10 templates. Therefore, the spectra from particulate emissions of burning materials can be easily discriminated from that of common atmospheric aerosol particles. The SFFS technology could be a good tool for monitoring burning pit emissions and possibly for distinguishing them from atmospheric aerosol particles.

  6. Demonstration of miniaturized 20mW CW 280nm and 266nm solid-state UV laser sources

    NASA Astrophysics Data System (ADS)

    Landru, Nicolas; Georges, Thierry; Beaurepaire, Julien; Le Guen, Bruno; Le Bail, Guy

    2015-02-01

    Visible 561 nm and 532 nm laser emissions from 14-mm long DPSS monolithic cavities are frequency converted to deep UV 280 nm and 266 nm in 16-mm long monolithic external cavities. Wavelength conversion is fully insensitive to mechanical vibrations and the whole UV laser sources fit in a miniaturized housing. More than 20 mW deep UV laser emission is demonstrated with high power stability, low noise and good beam quality. Aging tests are in progress but long lifetimes are expected thanks to the cavity design. Protein detection and deep UV resonant Raman spectroscopy are applications that could benefit from these laser sources.

  7. Evaluation of dental pulp repair using low level laser therapy (688 nm and 785 nm) morphologic study in capuchin monkeys

    NASA Astrophysics Data System (ADS)

    Pretel, H.; Oliveira, J. A.; Lizarelli, R. F. Z.; Ramalho, L. T. O.

    2009-02-01

    The aim of this study was to evaluate the hypothesis that low-level laser therapy (LLLT) 688 nm and 785 nm accelerate dentin barrier formation and repair process after traumatic pulp exposure. The sample consisted of 45 premolars of capuchin monkeys (Cebus apella) with pulp exposure Class V cavities. All premolars were treated with calcium hydroxide (Ca(OH)2), divided in groups of 15 teeth each, and analyzed on 7th, 25th, and 60th day. Group GI - only Ca(OH)2, GII - laser 688 nm, and GIII - laser 785 nm. Laser beam was used in single and punctual dose with the parameters: continuous, 688 nm and 785 nm wavelength, tip's area of 0.00785 cm2, power 50 mW, application time 20 s, dose 255 J/cm2, energy 2 J. Teeth were capped with Ca(OH)2, Ca(OH)2 cement and restored with amalgam. All groups presented pulp repair. On 25th day the thickness of the formed dentin barrier was different between the groups GI and GII (p < 0.05) and between groups GI and GIII (p < 0.01). On 60th day there was difference between GI and GIII (p < 0.01). It may be concluded that, LLLT 688 nm and 785 nm accelerated dentin barrier formation and consequently pulp repair process, with best results using infrared laser 785 nm.

  8. 1319 nm and 1356 nm dual-wavelength operation of diode-side-pumped Nd:YAG laser

    NASA Astrophysics Data System (ADS)

    Chen, Ming; Wang, Zhi-chao; Zhang, Shen-jin; Yang, Feng; Zhang, Feng-feng; Yuan, Lei; He, Miao; Li, Jia-jia; Zhang, Xiao-wen; Zong, Nan; Wang, Zhi-min; Bo, Yong; Peng, Qin-jun; Cui, Da-fu; Xu, Zu-yan

    2016-05-01

    We report the first demonstration on a diode-side-pumped quasi continuous wave (QCW) dual-wavelength Nd:YAG laser operating at 1319 nm and 1356 nm. The resonator adopts symmetrical L-shaped flat-flat structure working in a thermally near unstable cavity. By precise coating on the cavity mirrors, the simultaneous oscillation at 1319 nm and 1356 nm is delivered. A maximum dual-wavelength output power of 9.4 W is obtained. The beam quality factor M2 is measured to be 1.9.

  9. Characteristics of energetic solar flare electron spectra

    NASA Technical Reports Server (NTRS)

    Moses, Dan; Droege, Wolfgang; Meyer, Peter; Evenson, Paul

    1989-01-01

    A 55 event survey of energy spectra of 0.1-100 MeV interplanetary electrons originating from solar flares as measured by two spectrometers onboard the ISEE 3 (ICE) spacecraft for the years 1978-1982 has been completed. Spectra generated using the maximum flux of a given event in each energy channel were restricted to events with a well-defined flux rise time. Two broad groups of electron spectra are considered. In one group, the spectra are well represented by a single power law in rigidity with spectral index in the range 3-4.5. The spectra in the other group deviate from a power law in rigidity systematically in that they harden with increasing rigidity. Events with near power-law spectra are found to be correlated with long-duration soft X-ray events, whereas those with hardening spectra are correlated with short-duration events. The possible variation of acceleration and propagation processes with the properties of the flare site is discussed, using the duration of the soft X-ray flare emission as an indicator of the physical parameters of the flare site (flare volume, density, coronal height, and magnetic field geometry).

  10. Medium Resolution Spectra of Solar Illuminated Sounding Rocket Samarium Vapor Releases

    NASA Astrophysics Data System (ADS)

    Holmes, J. M.; Pedersen, T. R.; Miller, D.; Caton, R.; Bernhardt, P. A.

    2014-12-01

    Samarium spectra in the visible wavelengths (400-900 nm) are presented from the Metal Oxide Space Clouds (MOSC) sounding rocket launches of 2014 May 01 and 09. The two releases occurred in twilight at the ground, but with distinctly different solar elevation angles. Resonance-fluorescence spectral lines are identified throughout this wavelength range, and are attributed to Sm, Sm+, SmO and SmO+. Even given the wide spectral range of the instrument, the spectral resolution throughout the range was 1.5 nm or better. The time variation of spectral line intensity from various neutral and ionized atomic and molecular products are compared with a time dependent model of the samarium release, yielding estimates of photoionization rates, autoionization rates (reaction with O to form SmO+), and relative populations of energy levels giving rise to the spectra.

  11. Optimum conditions of the distributed bragg reflector in 850-nm GaAs infrared light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Ahn, Su-Chang; Lee, Byung-Teak; An, Won-Chan; Kim, Dae-Kwang; Jang, In-Kyu; So, Jin-Su; Lee, Hyung-Joo

    2016-07-01

    In this paper, a distributed Bragg reflector (DBR) for a bottom reflector in 850-nm GaAs infrared light-emitting diodes (Ir-LEDs) was developed and optimized. At an 850-nm wavelength, markedly improved reflection spectra were observed from DBRs consisting of Al1-xGaxAs/AlxGa1-xAs materials. In addition, the reflection spectra of Al1-xGaxAs/AlxGa1-xAs-based DBRs was found to increase with increasing difference between the high and the low refractive indices. At multiple layers of 10 pairs, maximal reflection spectra having about a 92% reflectivity were obtained from DBRs consisting of GaAs/AlAs. At 20 pairs, however, outstanding reflection spectra having a higher reflectivity and broader width were clearly observed from DBRs consisting of Al0.1Ga0.9As/Al0.9Ga0.1As. Some incident light appears to have been absorbed and confined by the narrow bandgap of the GaAs material used in DBRs consisting of GaAs/AlAs. This fact could be supported by the decrease in the reflectivity of the shorter wavelength region in DBRs consisting of GaAs/AlAs. For this reason, a remarkable output power could be obtained from the 850-nm GaAs Ir-LED chip having a DBR consisting of Al0.1Ga0.9As/Al0.9Ga0.1As.

  12. Broad-range neutron spectra identification in ultraintense laser interactions with carbon-deuterated plasma

    SciTech Connect

    Youssef, A.; Kodama, R.; Habara, H.; Tanaka, K.A.; Sentoku, Y.; Tampo, M.; Toyama, Y.

    2005-11-15

    Detailed neutron energy spectra produced from a CD2 target irradiated by a 450 fs, 20 J, 1053 nm laser at an intensity of 3x10{sup 18} W/cm{sup 2} have been studied. Wide-ranging neutron spectra were observed from two different observation angles 20 deg. and 70 deg. relative to the rear-side target normal. The experiment and numerically calculated spectra, by a three-dimensional Monte Carlo code, indicate that the range of the measured spectra is larger than that produced by the D(d,n){sup 3}He reaction. An interpretation for the measured spectra is introduced by considering the {sup 12}C(d,n){sup 13}N and D({sup 12}c,n){sup 13}N reactions. In addition, the study revealed that the neutron spectra produced by the D-C and C-D reactions can overlap that produced by the D-D reaction, and due to their high cross sections, comparing to the D-D reaction, both of them effectively participate in the neutron yield.

  13. Next-generation 193-nm laser for sub-100-nm lithography

    NASA Astrophysics Data System (ADS)

    Duffey, Thomas P.; Blumenstock, Gerry M.; Fleurov, Vladimir B.; Pan, Xiaojiang; Newman, Peter C.; Glatzel, Holger; Watson, Tom A.; Erxmeyer, J.; Kuschnereit, Ralf; Weigl, Bernhard

    2001-09-01

    The next generation 193 nm (ArF) laser has been designed and developed for high-volume production lithography. The NanoLithTM 7000, offering 20 Watts average output power at 4 kHz repetition rates is designed to support the highest exposure tool scan speeds for maximum productivity and wafer throughput. Fundamental design changes made to the laser core technologies are described. These advancements in core technology support the delivery of highly line-narrowed light with

  14. Applications of the 308-nm excimer laser in dermatology

    NASA Astrophysics Data System (ADS)

    Farkas, A.; Kemeny, L.

    2006-05-01

    Excimer lasers contain a mixture of a noble inert gas and a halogen, which form excited dimers only in the activated state. High-energy current is used to produce these dimers, which have a very short lifetime, and after their fast dissociation they release the excitation energy through ultraviolet photons. The application of these lasers proved to be successful in medicine, including the field of ophthalmology, cardiology, angiology, dentistry, orthopaedics, and, in recent years, dermatology. For medical purposes, the 193-nm argon fluoride, the 248-nm krypton fluoride, the 351-nm xenon fluoride, and the 308-nm xenon chloride lasers are used. Recently, the 308-nm xenon chloride laser has gained much attention as a very effective treatment modality in dermatological disorders. It was successfully utilized in psoriasis; later, it proved to be useful in handling other lightsensitive skin disorders and even in the treatment of allergic rhinitis. This review summarizes the possible applications of this promising tool in dermatology.

  15. Analysis of atmospheric spectra for trace gases

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Seals, Robert K., Jr.; Smith, Mary Ann H.; Goldman, Aaron; Murcray, David G.; Murcray, Frank J.

    1990-01-01

    The objective is the comprehensive analysis of high resolution atmospheric spectra recorded in the middle-infrared region to obtain simultaneous measurements of coupled parameters (gas concentrations of key trace constituents, total column amounts, pressure, and temperature) in the stratosphere and upper troposphere. Solar absorption spectra recorded at 0.002 and 0.02 cm exp -1 resolutions with the University of Denver group's balloon-borne, aircraft borne, and ground-based interferometers and 0.005 to 0.01 cm exp -1 resolution solar spectra from Kitt Peak are used in the analyses.

  16. The Infrared Spectra and Absorption Intensities of Amorphous Ices

    NASA Astrophysics Data System (ADS)

    Gerakines, Perry A.; Hudson, Reggie L.; Loeffler, Mark

    2016-06-01

    Our research group is carrying out new IR measurements of icy solids relevant to the outer solar system and to the interstellar medium, with an emphasis on amorphous and crystalline ices below ~ 120 K. Our goal is to update and add to the relatively meager literature on this subject and to provide electronic versions of state-of-the-art data, since the abundances of such molecules cannot be deduced without accurate reference spectra and IR band strengths. In the past year, we have focused on three of the simplest and most abundant components of interstellar and solar-system ices: methane (CH4), carbon dioxide (CO2), and methanol (CH3OH). Infrared spectra from ˜ 4500 to 500 cm-1 have been measured for each of these molecules in μm-thick films at temperatures from 10 to 120 K. All known amorphous and crystalline phases have been reproduced and, for some, presented for the first time. We also report measurements of the index of refraction at 670 nm and the mass densities for each ice phase. Comparisons are made to earlier work where possible. Electronic versions of our new results are available at http://science.gsfc.nasa.gov/691/cosmicice/ constants.html.

  17. Mapping Agricultural Crops with AVIRIS Spectra in Washington State

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Pavri, Betina; Roberts, Dar; Ustin, Susan

    2000-01-01

    Spectroscopy is used in the laboratory to measure the molecular components and concentrations of plant constituents to answer questions about the plant type, status, and health. Imaging spectrometers measure the upwelling spectral radiance above the Earth's surface as images. Ideally, imaging spectrometer data sets should be used to understand plant type, plant status, and health of plants in an agricultural setting. An Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data set was acquired over agricultural fields near Wallula, Washington on July 23rd, 1997. AVIRIS measures upwelling radiance spectra through 224 spectral channels with contiguous 10-nm sampling from 400 to 2500 run in the solar-reflected spectrum. The spectra are measured as images of 11 by up to 800 km with 20-m spatial resolution. The spectral images measured by AVIRIS represent the integrated signal resulting from: the solar irradiance; two way transmittance and scattering of the atmosphere; the absorptions and scattering of surface materials; as well as the spectral, radiometric and spatial response functions of AVIRIS. This paper presents initial research to derive properties of the agricultural fields near Wallula from the calibrated spectral images measured by AVIRIS near the top of the atmosphere.

  18. Transient absorption spectra of the laser-dressed hydrogen atom

    NASA Astrophysics Data System (ADS)

    Murakami, Mitsuko; Chu, Shih-I.

    2013-10-01

    We present a theoretical study of transient absorption spectra of laser-dressed hydrogen atoms, based on numerical solutions of the time-dependent Schrödinger equation. The timing of absorption is controlled by the delay between an extreme ultra violet (XUV) pulse and an infrared (IR) laser field. The XUV pulse is isolated and several hundred attoseconds in duration, which acts as a pump to drive the ground-state electron to excited p states. The subsequent interaction with the IR field produces dressed states, which manifest as sidebands between the 1s-np absorption spectra separated by one IR-photon energy. We demonstrate that the population of dressed states is maximized when the timing of the XUV pulse coincides with the zero crossing of the IR field, and that their energies can be manipulated in a subcycle time scale by adding a chirp to the IR field. An alternative perspective to the problem is to think of the XUV pulse as a probe to detect the dynamical ac Stark shifts. Our results indicate that the accidental degeneracy of the hydrogen excited states is removed while they are dressed by the IR field, leading to large ac Stark shifts. Furthermore, we observe the Autler-Townes doublets for the n=2 and 3 levels using the 656 nm dressing field, but their separation does not agree with the prediction by the conventional three-level model that neglects the dynamical ac Stark shifts.

  19. Resonance Raman spectra of. cap alpha. -copper phthalocyanine

    SciTech Connect

    Bovill, A.J.; McConnell, A.A.; Nimmo, J.A.; Smith, W.E.

    1986-02-13

    Raman spectra of ..cap alpha..-copper phthalocyanine (..cap alpha..-CuPc) were recorded at room temperature and at 10 K with excitation wavelengths between 457 and 714 nm. Resonance enhancement was greatest for modes for which the largest displacements were on either the inner five-membered ring of the isoindole groups or the inner macrocycle and consequently assignment of the bands to modes of the entire molecule was possible by comparison with nickel octaethylporphyrin. Four out of five bands resonant in the Q band region and preresonant near the B band absorption region are totally symmetric modes. B band preresonance occurs more strongly with high-frequency modes. At low temperatures, multimode interactions are reduced and profiles were obtained which can be compared with solution profiles of porphyrins. Both Q/sub x/ and Q/sub y/ 0-0 scattering can be identified and a helper mode is evident. A term enhancement predominates, with B/sub 1g/ and B/sub 2g/ modes enhanced because of a Jahn-Teller distortion of the excited state. The resonance studies, together with electronic absorption spectra and published theoretical studies, confirm that the Q band in ..cap alpha..-CuPc is largely due to an allowed ..pi..-..pi..* transition associated mainly with the macrocycle and inner five-membered rings of the isoindole groups. 25 references, 5 figures, 2 tables.

  20. Fluorescence Emission and Excitation Spectra of Photo-Fragmented Nitrobenzene.

    NASA Astrophysics Data System (ADS)

    Lue, Christopher J.; Tanjaroon, Chakree; Johnson, J. Bruce; Allen, Susan D.; Reeve, Scott W.

    2012-06-01

    Upon absorption of a UV photon, nitrobenzene readily dissociates into C_6H_5, NO_2, C_6H_5NO, O, C_6H_5O, and NO through three different channels. We have recorded high resolution emission and excitation spectra of the NO resulting from photo-fragmented nitrobenzene using a pulsed picosecond tunable laser and a nanosecond dye laser. Specifically, the lasers probed the A^2Σ^+→ X^2π(1/2,3/2) NO band system between 225-260 nm using an one or two color process. In a one color process, the same energy (wavelength) photon is used to dissociate nitrobenzene and excite NO. In a two color process, photons of a particular energy are used to dissociate the nitrobenzene while photons of a different energy are used to probe the resultant NO. We have determined the rotational and vibrational temperatures of the nascent NO. And, we have examined the effect of the relative timing of the two photons on the fluorescence spectra to extract information about the photodissociation dynamics. Lin, M.-F.; Lee, Y. T.; Ni, C.-K.; Xu, S. and Lin, M. C. J. Chem. Phys., AIP, 2007, 126.

  1. The Infrared Spectra and Absorption Intensities of Amorphous Ices

    NASA Astrophysics Data System (ADS)

    Gerakines, Perry A.; Hudson, Reggie L.; Loeffler, Mark

    2016-06-01

    Our research group is carrying out new IR measurements of icy solids relevant to the outer solar system and to the interstellar medium, with an emphasis on amorphous and crystalline ices below ~ 120 K. Our goal is to update and add to the relatively meager literature on this subject and to provide electronic versions of state-of-the-art data, since the abundances of such molecules cannot be deduced without accurate reference spectra and IR band strengths. In the past year, we have focused on three of the simplest and most abundant components of interstellar and solar-system ices: methane (CH4), carbon dioxide (CO2), and methanol (CH3OH). Infrared spectra from ∼ 4500 to 500 cm-1 have been measured for each of these molecules in μm-thick films at temperatures from 10 to 120 K. All known amorphous and crystalline phases have been reproduced and, for some, presented for the first time. We also report measurements of the index of refraction at 670 nm and the mass densities for each ice phase. Comparisons are made to earlier work where possible. Electronic versions of our new results are available at http://science.gsfc.nasa.gov/691/cosmicice/ constants.html.

  2. Direct measurement of pure absorbance spectra of living phototrophic microorganisms.

    PubMed

    Göbel, F

    1978-02-01

    The pure absorbance of turbid cell suspensions of various phototrophic microorganisms were determined by collecting the scattered light. A conventional spectrophotometer was used, equipped with an intergrating sphere as receiver unit, which allowed precise measurements of the absorbance in the range from zero to 0.1. In the wavelength range 300--1100 nm, where photosynthesis occurs, light scattered only once by a bacterial cell retains predominantly the forward direction. This allows measurements of pure absorption, when the concentration of cells which the light has to pass through is small. For example, by comparison of measurements of pigmented and nonpigmented cell suspensions of Rhodopseudomonas acidophila, it was shown that the total sum of scattered light can be collected. The best results were obtained using cuvettes with a light path of 0.1 cm or 0.2 cm to measure cell suspensions of about 0.2 mg dry weight per ml. For R. acidophila this corresponds to 1--3 cell layers. Extinction-, absorbance- and scattering spectra for R. acidophila are presented, in addition to the absorbance spectra for Rhodospirillum rubrum, Aphanocapsa and Scenedesmus.

  3. [Decomposition of hemoglobin UV absorption spectrum into absorption spectra of prosthetic group and apoprotein by means of an additive model].

    PubMed

    Lavrinenko, I A; Vashanov, G A; Artyukhov, V G

    2015-01-01

    The decomposition pathways of hemoglobin UV absorption spectrum into the absorption spectra of the protein and non-protein components are proposed and substantiated by means of an additive model. We have established that the heme component has an absorption band with a maximum at λ(max) = 269.2 nm (ε = 97163) and the apoprotein component has an absorption band with a maximum at λ(max) = 278.4 nm (ε = 48669) for the wavelength range from 240.0 to 320.0 nm. An integral relative proportion of absorption for the heme fraction (78.8%) and apoprotein (21.2%) in the investigating wavelength range is defined.

  4. Theoretical investigations of absorption and fluorescence spectra of protonated pyrene.

    PubMed

    Chin, Chih-Hao; Lin, Sheng Hsien

    2016-05-25

    The equilibrium geometry and 75 vibrational normal-mode frequencies of the ground and first excited states of protonated pyrene isomers were calculated and characterized in the adiabatic representation by using the complete active space self-consistent field (CASSCF) method. Electronic absorption spectra of solid neon matrixes in the wavelength range 495-415 nm were determined by Maier et al. and they were analyzed using time-dependent density functional theory calculations (TDDFT). CASSCF calculations and absorption and emission spectra simulations by one-photon excitation equations were used to optimize the excited and ground state structures of protonated pyrene isomers. The absorption band was attributed to the S0 → S1 electronic transition in 1H-Py(+), and a band origin was used at 20580.96 cm(-1). The displaced harmonic oscillator approximation and Franck-Condon approximation were used to simulate the absorption spectrum of the (1) (1)A' ← X[combining tilde](1)A' transition of 1H-Py(+), and the main vibronic transitions were assigned for the first ππ* state. It shows that the vibronic structures were dominated by one of the eight active totally symmetric modes, with ν15 being the most crucial. This indicates that the electronic transition of the S1((1)A') state calculated in the adiabatic representation effectively includes a contribution from the adiabatic vibronic coupling through Franck-Condon factors perturbed by harmonic oscillators. The present method can adequately reproduce experimental absorption and fluorescence spectra of a gas phase. PMID:27181017

  5. [Time resolved UV-Vis absorption spectra of quercetin reacting with various concentrations of sodium hydroxide].

    PubMed

    Yang, Li-Jun; Li, Ping; Gao, Yan-Jun; Li, Hui-Feng; Wu, Da-Cheng; Li, Rui-Xia

    2009-06-01

    A real time investigation of chemical reaction process of quercetin with various concentrations of sodium hydroxide was performed by using an intensified spectroscopic detector ICCD. The time resolved UV-Vis absorption spectra of 5 x 10(-5) mol x L(-1) quercetin respectively reacting with sodium hydroxide at concentrations of 2, 0.2, 0.1, 0.04 and 0.02 mol x L(-1) were acquired. A total of 200 spectra with the same exposure time of 0.1 ms for each spectrum but different time interval between two consecutive spectra were recorded for each reaction. The first 50 spectra have the time interval of 20 ms, the next 50 have 1 s, and the last 100 have 2 s. Results indicate that quercetin reacted with sodium hydroxide easily and there was an intermediate product formed during the reaction, with different concentrations of reactants, the changes of absorption bands were the same, but the moments at which the changes happened were different and the total reaction time was various from 1 s to 100 s. Spectra recorded showed the disappearing process of the typical bands centered at 254 and 374 nm of pure quercetin, the growing and disappearing processes of a new band centered at 427 nm of the intermediate product, and the growing process of the new band centered at 314 nm of the final product obviously. No other transient spectroscopic data are currently available on the reaction of quercrtin with sodium hydroxide, the results obtained in the present work provide useful experimental data for the study of the microscopic process of the reaction.

  6. Rapid discrimination of enhanced quality pork by visible and near infrared spectroscopy.

    PubMed

    Prieto, N; Juárez, M; Larsen, I L; López-Campos, Ó; Zijlstra, R T; Aalhus, J L

    2015-12-01

    This study tested the ability of visible and near infrared spectroscopy (Vis-NIRS) to discriminate enhanced quality pork. Vis-NIR spectra were collected on intact chops from 148 pork carcasses using a portable LabSpec®4 spectrometer (350-2500 nm). Partial least squares discriminant analyses based on Vis-NIR spectra correctly classified 94, 95 and 100% of the 2d, and 95, 98 and 100% of the 14 d aged pork samples within Lacombe, Duroc and Iberian pig breeds, respectively. Moreover, Vis-NIRS correctly classified 97 and 99% of the moisture enhanced (ME) and Non-ME pork samples aged for 2d, and 94 and 95% of those aged for 14 d, as well as 94 and 97% of the 2 and 14 d aged pork samples, respectively. Conversely, Vis-NIRS technology could not differentiate pork samples based on pre-slaughter diet or post-slaughter carcass chilling process. Vis-NIRS can segregate enhanced quality pork according to production factors and post-mortem strategies such as pig breed, moisture enhancing and ageing period. PMID:26188360

  7. 1064 nm laser emission of highly doped Nd: Yttrium aluminum garnet under 885 nm diode laser pumping

    NASA Astrophysics Data System (ADS)

    Lupei, V.; Pavel, N.; Taira, T.

    2002-06-01

    Highly efficient 1064 nm continuous-wave laser emission under 885 nm diode pumping in concentrated Nd: Yttrium aluminum garnet (YAG) crystals (up to 3.5 at. % Nd) and ceramics (up to 3.8 at. % Nd) is reported. A highly doped (2.4 at. %) Nd:YAG laser, passively Q switched by a Cr4+:YAG saturable absorber, is demonstrated.

  8. Wavelength dependence on the forensic analysis of glass by nanosecond 266 nm and 1064 nm laser induced breakdown spectroscopy

    SciTech Connect

    Cahoon, Erica M.; Almirall, Jose R.

    2010-05-01

    Laser induced breakdown spectroscopy can be used for the chemical characterization of glass to provide evidence of an association between a fragment found at a crime scene to a source of glass of known origin. Two different laser irradiances, 266 nm and 1064 nm, were used to conduct qualitative and quantitative analysis of glass standards. Single-pulse and double-pulse configurations and lens-to-sample-distance settings were optimized to yield the best laser-glass coupling. Laser energy and acquisition timing delays were also optimized to result in the highest signal-to-noise ratio corresponding to the highest precision and accuracy. The crater morphology was examined and the mass removed was calculated for both the 266 nm and 1064 nm irradiations. The analytical figures of merit suggest that the 266 nm and 1064 nm wavelengths are capable of good performance for the forensic chemical characterization of glass. The results presented here suggest that the 266 nm laser produces a better laser-glass matrix coupling, resulting in a better stoichiometric representation of the glass sample. The 266 nm irradiance is therefore recommended for the forensic analysis and comparison of glass samples.

  9. Line broadening in the neutral and ionized mercury spectra

    NASA Astrophysics Data System (ADS)

    Gavrilov, M.; Skočić, M.; Burger, M.; Bukvić, S.; Djeniže, S.

    2012-10-01

    The neutral, singly, doubly and triply ionized mercury (Hg I-IV, respectively) spectral line shapes and line center positions have been investigated in the laboratory helium plasma at electron densities ranging between 9.3 × 1022 m-3 and 1.93 × 1023 m-3 and electron temperatures around 19,500 K, both interesting for astrophysics. The mercury (natural isotope composition) atoms were sputtered from the cylindrical amalgamated gold plates located in the homogenous part of the pulsed helium discharge operating at a pressure of 665 Pa in a flowing regime. The mercury spectral line profiles were recorded using the McPherson model 209 spectrograph and the Andor ICCD camera as the detection system. This research presents Stark broadening parameters, the width (W) and the shift (d), of one Hg I, 19 Hg II, 6 Hg III and 4 Hg IV lines, not investigated so far. Our experimental W values were compared with the data calculated applying various approaches. The shape and intensity of astrophysically important 398.4 nm Hg II spectral line was discussed taking into account the isotope shift, hyperfine structure and Penning effects. At the mentioned plasma parameters the Stark broadening is found to be a main line broadening mechanism of the lines (λ > 200 nm) in the Hg I-IV spectra.

  10. Vertebrate ancient opsin photopigment spectra and the avian photoperiodic response.

    PubMed

    Davies, Wayne I L; Turton, Michael; Peirson, Stuart N; Follett, Brian K; Halford, Stephanie; Garcia-Fernandez, Jose M; Sharp, Peter J; Hankins, Mark W; Foster, Russell G

    2012-04-23

    In mammals, photoreception is restricted to cones, rods and a subset of retinal ganglion cells. By contrast, non-mammalian vertebrates possess many extraocular photoreceptors but in many cases the role of these photoreceptors and their underlying photopigments is unknown. In birds, deep brain photoreceptors have been shown to sense photic changes in daylength (photoperiod) and mediate seasonal reproduction. Nonetheless, the specific identity of the opsin photopigment 'sensor' involved has remained elusive. Previously, we showed that vertebrate ancient (VA) opsin is expressed in avian hypothalamic neurons and forms a photosensitive molecule. However, a direct functional link between VA opsin and the regulation of seasonal biology was absent. Here, we report the in vivo and in vitro absorption spectra (λ(max) = ~490 nm) for chicken VA photopigments. Furthermore, the spectral sensitivity of these photopigments match the peak absorbance of the avian photoperiodic response (λ(max) = 492 nm) and permits maximum photon capture within the restricted light environment of the hypothalamus. Such a correspondence argues strongly that VA opsin plays a key role in regulating seasonal reproduction in birds.

  11. [Spectra of dark green jade from Myanmar].

    PubMed

    Mao, Jian; Chai, Lin-Tao; Guo, Shou-Guo; Fan, Jian-Liang; Bao, Feng

    2013-05-01

    Chemical compositions and spectral characteristics of one type of dark green jades assumed from omphacite jadeite from Myanmar jadeite mining area were studied by X-ray powder diffraction(XRD), X-ray fluorescence spectra(XRF), Raman spectra(RM) and UV-Vis Spectroscopy, etc. Based on testing by XRD and XRF, it was shown that it belongs to iron-enriched plagioclase, including albite and anorthite. The compositions range is between Ab0.731 An0.264 Or0.004 and Ab0.693 An0.303 Or0.004. Raman spectra of samples, albite jade and anorthite were collected and analyzed. Additionally, the distributions of Si, Al in the crystal structure were also discussed. UV-Vis spectra showed that dark green hue of this mineral is associated with d--d electronic transition of Fe3+ and Cr3+.

  12. Ultraviolet Spectra of Globular Clusters in Andromeda

    NASA Astrophysics Data System (ADS)

    Peterson, R. C.

    1999-05-01

    As part of a NASA-funded effort with Ben Dorman of Goddard Space Flight Center, I am engaged in calculating spectra from first principles of solar-type stars of a wide range of metallicity. This paper reports on an extension of this work funded by the Hubble Space Telescope archival program, the derivation of fundamental parameters for several globular clusters in Andromeda (M31). Properties of the underlying stellar population are derived by matching archival HST spectra with composite spectra constructed by weighted coaddition of the calculated spectra for stars of appropriate spectral types. Armed with these ab initio calculations, this work explores the degeneracy in age and metallicity in the ultraviolet, and the affect of unknowns such as the relative abundance of light elements versus iron and the possible presence of blue stragglers or blue horizontal branch stars.

  13. Dynamic radio spectra from two fireballs

    NASA Astrophysics Data System (ADS)

    Obenberger, K. S.; Taylor, G. B.; Lin, C. S.; Dowell, J.; Schinzel, F. K.; Stovall, K.

    2015-11-01

    We present dynamic spectra from the Long Wavelength Array telescope of two large meteors (fireballs) observed to emit between 37 and 54 MHz. These spectra show the first ever recorded broadband measurements of this newly discovered VHF emission. The spectra show that the emission is smooth and steep, getting very bright at lower frequencies. We suggest that this signal is possibly emission of Langmuir waves and that these waves could be excited by a bump-on-tail instability within the trail. The spectra of one fireball display broadband temporal frequency sweeps. We suggest that these sweeps are evidence of individual expanding clumps of emitting plasma. While some of these proposed clumps may have formed at the very beginning of the fireball event, others must have formed seconds after the initial event.

  14. Study on Raman spectra of synthetic celluloses

    NASA Astrophysics Data System (ADS)

    Tong, Na; Zhu, Changjun; Zhang, Yixin

    2015-02-01

    Raman spectrometry was employed to study the characteristics of Raman spectra of aliphatic polyamide fiber and polyethylene terephthalate (PET), which were treated with sodium hydroxide, sulfuric acid and copper sulfate, respectively. Raman spectra under different conditions were obtained and the characteristics of the Raman spectra were analyzed. The results show that Raman peaks beyond 1200 cm-1 appear for aliphatic polyamide fiber processed by sodium hydroxide, while the Raman peaks beyond 1000 cm-1 disappear for aliphatic polyamide fiber processed by sulfuric acid. Raman peaks beyond 1750 cm-1 decrease for polyethylene terephthalate processed by sodium hydroxide, while Raman peaks beyond 1000 cm-1 disappear, except weak peaks around 3000 cm-1 , for polyethylene terephthalate processed by sulfuric acid. The variations of the Raman spectra are primarily related to the changes of chemical bonds and molecular structures.

  15. Investigation of Raman spectra of polyethylene terephthalate

    NASA Astrophysics Data System (ADS)

    Zhu, Changjun; Tong, Na; Song, Lixin; Zhang, Guoqing

    2015-08-01

    Raman spectrometry was employed to study the characteristics of Raman spectra of polyethylene terephthalate (PET), which were treated with sodium hydroxide, sulfuric acid and copper sulfate, respectively. Raman spectra under different conditions were obtained and the characteristics of the Raman spectra were analyzed. The morphology structures were observed under different conditions using Atomic Force Microscope. The results show that the spectral intensity of PET treated with sodium hydroxide is higher than that untreated between 200-1750 cm-1, while the intensity of PET treated with sodium hydroxide is lower than that untreated beyond 1750 cm-1 and the fluorescence background of Raman spectra is decreased. The spectral intensity of PET treated with sulfuric acid is remarkably reduced than that untreated, and the intensity of PET treated with copper sulphate is much higher than that untreated.

  16. Synthesis and Spectra of Vanadium Complexes.

    ERIC Educational Resources Information Center

    Ophardt, Charles E.; Stupgia, Sean

    1984-01-01

    Describes an experiment which illustrates simple synthetic techniques, redox principles in synthesis reactions, interpretation of visible spectra using Orgel diagrams, and the spectrochemical series. The experiment is suitable for the advanced undergraduate inorganic chemistry laboratory. (JN)

  17. Vibrational and vibronic spectra of tryptamine conformers

    NASA Astrophysics Data System (ADS)

    Mayorkas, Nitzan; Bernat, Amir; Izbitski, Shay; Bar, Ilana

    2013-03-01

    Conformation-specific ionization-detected stimulated Raman spectra, including both Raman loss and Raman gain lines, along with visible-visible-ultraviolet hole-burning spectra of tryptamine (TRA) conformers have been measured simultaneously, with the aim of obtaining new data for identifying them. The slightly different orientations of the ethylamine side chain relative to the indole lead to unique spectral signatures, pointing to the presence of seven TRA conformers in the molecular beam. Comparison of ionization-loss stimulated Raman spectra to computationally scaled harmonic Raman spectra, especially in the alkyl C-H and amine N-H stretch regions together with the retrieved information on the stabilities of the TRA conformers assisted their characterization and structural identification. The prospects and limitations of using these spectroscopic methods as potential conformational probes of flexible molecules are discussed.

  18. Contribution to the study of turbulence spectra

    NASA Technical Reports Server (NTRS)

    Dumas, R.

    1979-01-01

    An apparatus suitable for turbulence measurement between ranges of 1 to 5000 cps and from 6 to 16,000 cps was developed and is described. Turbulence spectra downstream of the grills were examined with reference to their general characteristics, their LF qualities, and the effects of periodic turbulence. Medium and HF are discussed. Turbulence spectra in the boundary layers are similarly examined, with reference to their fluctuations at right angles to the wall, and to lateral fluctuations. Turbulence spectra in a boundary layer with suction to the wall is discussed. Induced turbulence, and turbulence spectra at high Reynolds numbers. Calculations are presented relating to the effect of filtering on the value of the correlations in time and space.

  19. Microwave spectra of some volatile organic compounds

    NASA Technical Reports Server (NTRS)

    White, W. F.

    1975-01-01

    A computer-controlled microwave (MRR) spectrometer was used to catalog reference spectra for chemical analysis. Tables of absorption frequency, peak absorption intensity, and integrated intensity are included for 26 volatile organic compounds, all but one of which contain oxygen.

  20. Frequency Spectra of Magnetoacoustic Emission in Meteorites

    NASA Astrophysics Data System (ADS)

    Ivanchenko, S. V.; Grokhovsky, V. I.; Kolchanov, N. N.

    2016-08-01

    We analyzed the magnetoacoustic emission spectra of iron meteorites and their industrial analogs. The revealed differences in signal amplitude, position and width of the peaks are associated with the features of structure and the magnetic texture.

  1. Cooperative Interaction Within RNA Virus Mutant Spectra.

    PubMed

    Shirogane, Yuta; Watanabe, Shumpei; Yanagi, Yusuke

    2016-01-01

    RNA viruses usually consist of mutant spectra because of high error rates of viral RNA polymerases. Growth competition occurs among different viral variants, and the fittest clones predominate under given conditions. Individual variants, however, may not be entirely independent of each other, and internal interactions within mutant spectra can occur. Examples of cooperative and interfering interactions that exert enhancing and suppressing effects on replication of the wild-type virus, respectively, have been described, but their underlying mechanisms have not been well defined. It was recently found that the cooperation between wild-type and variant measles virus genomes produces a new phenotype through the heterooligomer formation of a viral protein. This observation provides a molecular mechanism underlying cooperative interactions within mutant spectra. Careful attention to individual sequences, in addition to consensus sequences, may disclose further examples of internal interactions within mutant spectra. PMID:26162566

  2. Handbook of mass spectra of environmental contaminants

    SciTech Connect

    Hites, R.A.

    1985-01-01

    This handbook is a collection of the electron impact mass spectra of 394 commonly encountered environmental pollutants. Each page is devoted to the examination of a single pollutant, which is presented as a bar graph always starting at M/z = 40. Each spectra is determined by analyses of data in EPA data bases. The major fragment ions are correlated with their respective structure. The mass and intensity of the four most intense ions in the spectrum are given. Each spectrum is marked to indicate the origin of the selected fragment ions. For each spectra, also given are the approved name of the chemical Abstract Service, the common name of the compound, the article number (if any) given to the Merck Index, the CAS Registry Number, the molecular formula, and the nominal molecular weight of the compound. Each spectra is indexed by common chemical name, CAS Registry Number, exact molecular weight, and intense peaks.

  3. Comparing Ultraviolet Spectra Against Calculations: First Results

    NASA Technical Reports Server (NTRS)

    Peterson, Ruth C.

    2003-01-01

    The five-year goal of this effort is to calculate high fidelity mid-UV spectra for individual stars and stellar systems for a wide range of ages, abundances, and abundance ratios. In this first year, the emphasis was placed on revising the list of atomic line parameters used to calculate mid-UV spectra. First, new identifications of atomic lines and measurements of their transition probabilities were obtained for lines of the first and second ionization stages of iron-peak elements. Second, observed mid-UV and optical spectra for standard stars were re-analyzed and compared to new calculations, to refine the determination of transition probabilities and to estimate the identity of lines still missing from the laboratory lists. As evidenced by the figures, a dramatic improvement has resulted in the reproduction of the spectra of standard stars by the calculations.

  4. Improved peak shape fitting in alpha spectra.

    PubMed

    Pommé, S; Caro Marroyo, B

    2015-02-01

    Peak overlap is a recurrent issue in alpha-particle spectrometry, not only in routine analyses but also in the high-resolution spectra from which reference values for alpha emission probabilities are derived. In this work, improved peak shape formulae are presented for the deconvolution of alpha-particle spectra. They have been implemented as fit functions in a spreadsheet application and optimum fit parameters were searched with built-in optimisation routines. Deconvolution results are shown for a few challenging spectra with high statistical precision. The algorithm outperforms the best available routines for high-resolution spectrometry, which may facilitate a more reliable determination of alpha emission probabilities in the future. It is also applicable to alpha spectra with inferior energy resolution. PMID:25497323

  5. PIA update: Correlation analyses of mass spectra

    NASA Technical Reports Server (NTRS)

    Mason, L. W.; Clark, B. C.

    1988-01-01

    The PIA instrument aboard the Giotto spacecraft (a time of flight spectrometer) has been presented elsewhere. The mass spectra used in this analysis were decoded and mass numbers assigned according to the presence of carbon and silver, using the global values for these elements in their spectral absence. The results presented here were obtained using a frequency of occurrence based on analysis which correlated how often mass numbers appear in the mass spectra and which mass numbers tend to occur together in the same spectra; no amplitude information is utilized. The data are presented as plots of mass vs coincident mass for different subsets of the PIA data set, with both axes having units of atomic mass. Frequency contours are plotted at approximately five percent contour intervals, relative to the maximum AMU occurrence in that plot. The plots presented are symmetrical about the matrix diagonal, i.e., every mass is coincident with itself in a given spectra.

  6. [Study on the absorption and fluorescence spectra of ethylene glycol and glycerol].

    PubMed

    Xu, Hui; Zhu, Tuo; Yu, Rui-Peng

    2007-07-01

    The absorption and fluorescence spectra of ethylene glycol and glycerol solution induced by UV light were studied respectively in the present paper. The most intense absorption wavelength for both of them was located at 198 nm. Moreover, fluorescence was detected when induced by suitable UV light, and the corresponding fluorescence spectra were listed. But there is no obvious relationship found between the fluorescence intensity and the excited wavelength, and a further research should be done. From the first derivative fluorescence spectra of ethylene glycol, it was concluded that under the UV light of 210 nm, the variation speed for relative intensity proved to be the fastest. In contrast, when excited by 225 nm, the speed proved to be the slowest. In addition, based on the quantum calculation and the transition from HOMO to LUMO of electronics in one-dimensional quantum well, the authors attempted to give out the value of absorption wavelength. In consideration of the bond-length variety brought out by the chain processing, the error between the experimental and calculation values should be apprehensible, and the latter can serve as some reference value in theory.

  7. Measurement of Fluorescence Spectra from Ambient Aerosol Particles Using Laser-induced Fluorescence Technique

    NASA Astrophysics Data System (ADS)

    Taketani, F.; Kanaya, Y.; Nakamura, T.; Moteki, N.; Takegawa, N.

    2011-12-01

    To obtain the information of composition of organic aerosol particles in atmosphere, we developed an instrument using laser-induced fluorescence (LIF) technique. To measure the fluorescence from a particle, we employed two lasers. Scattering light signal derived from a single particle upon crossing the 635nm-CW laser triggers the 266nm-pulsed laser to excite the particle. Fluorescence from the particle in the wavelength range 300-600nm is spectrally dispersed by a grating spectrometer and then detected by a 32-Ch photo-multiplier tube(PMT). The aerosol stream is surrounded by a coaxial sheath air flow and delivered to the optical chamber at atmospheric pressure. Using PSL particles with known sizes, we made a calibration curve to estimate particle size from scattering light intensity. With the current setup of the instrument we are able to detect both scattering and fluorescence from particles whose diameters are larger than 0.5um. Our system was able to differentiate particles composed of mono-aromatic species (e.g. Tryptophan) from those of Riboflavin, by their different fluorescence wavelengths. Also, measurements of fluorescence spectra of ambient particles were demonstrated in our campus in Yokosuka city, facing Tokyo bay in Japan. We obtained several types of florescence spectra in the 8 hours. Classification of the measured fluorescence spectra will be discussed in the presentation.

  8. Plastocyanin conformation: an analysis of its near ultraviolet absorption and circular dichroic spectra

    SciTech Connect

    Draheim, J.E.; Anderson, G.P.; Duane, J.W.; Gross, E.L.

    1986-04-01

    The near-ultraviolet absorption and circular dichroic spectra of plastocyanin are dependent upon the redox state, solution pH, and ammonium sulfate concentration. This dependency was observed in plastocyanin isolated from spinach, poplar, and lettuce. Removal of the copper atom also perturbed the near-ultraviolet spectra. Upon reduction there are increases in both extinction and ellipticity at 252 nm. Further increases at 252 nm were observed upon formation of apo plastocyanin eliminating charge transfer transitions as the cause. The spectral changes in the near-ultraviolet imply a flexible tertiary conformation for plastocyanin. There are at least two charge transfer transitions at approx.295-340 nm. One of these transitions is sensitive to low pH's and is attributed to the His 87 copper ligand. The redox state dependent changes observed in the near-ultraviolet spectra of plastocyanin are attenuated either by decreasing the pH to 5 or by increasing the ammonium sulfate concentration to 2.7 M. This attenuation cannot be easily explained by simple charge screening. Hydrophobic interactions probably play an important role in this phenomenon. The pH and redox state dependent conformational changes may play an important role in regulating electron transport.

  9. TL emission spectra measurements using a spectrometer coupled to the Risoe TL/OSL reader

    NASA Astrophysics Data System (ADS)

    Yoshizumi, Maíra T.; Caldas, Linda V. E.

    2014-11-01

    A high sensitivity spectrometer (Ocean Optics QE65 Pro) was coupled to the Risoe TL/OSL reader to measure TL emission spectra of four different dosimeters. This spectrometer is based on a Hamamatsu FFT-CCD detector with a 2-D arrangement of pixels (1044×64), which detects luminescence in a range of 200-950 nm. An optical fiber was used to guide the signal from the sample to the spectrometer. TL spectra from LiF, CaSO4:Dy, BeO and Al2O3:C detectors were obtained and they are presented in this work. The proposed detection system showed good response; spectra shape, in accordance with the literature, were obtained, validating the system.

  10. Microwave Spectra and Structures of H_2O\\cdotsAgF

    NASA Astrophysics Data System (ADS)

    Stephens, S. L.; Walker, N. R.; Tew, D. P.; Legon, A. C.

    2011-06-01

    A Balle-Flygare FT-MW spectrometer coupled to a laser ablation source has been used to measure the pure rotational spectra of H2O\\cdotsAgF. Generation is via laser ablation (532 nm) of a silver rod in the presence of SF6, argon, a low partial pressure of H2O and the molecules are stabilized by supersonic expansion. The spectra of eight isotopologues have been measured. Rotational constants, B0 and C0, and the centrifugal distortion constant, Δ _J have been determined. Isotopic substitutions are available at the silver, oxygen and hydrogen atoms. The spectra are consistent with a linear arrangement of oxygen, silver and fluorine atoms and the structure is either C2v planar at equilibrium or CS pyramidal but with a low potential-energy barrier to planarity such that the v = 0 and 1 states associated with the motion that inverts the configuration at the O atom are well separated.

  11. Infrared and Ultraviolet Spectra of Diborane(6): B2H6 and B2D6.

    PubMed

    Peng, Yu-Chain; Chou, Sheng-Lung; Lo, Jen-Iu; Lin, Meng-Yeh; Lu, Hsiao-Chi; Cheng, Bing-Ming; Ogilvie, J F

    2016-07-21

    We recorded absorption spectra of diborane(6), B2H6 and B2D6, dispersed in solid neon near 4 K in both mid-infrared and ultraviolet regions. For gaseous B2H6 from 105 to 300 nm, we report quantitative absolute cross sections; for solid B2H6 and for B2H6 dispersed in solid neon, we measured ultraviolet absorbance with relative intensities over a wide range. To assign the mid-infrared spectra to specific isotopic variants, we applied the abundance of (11)B and (10)B in natural proportions; we undertook quantum-chemical calculations of wavenumbers associated with anharmonic vibrational modes and the intensities of the harmonic vibrational modes. To aid an interpretation of the ultraviolet spectra, we calculated the energies of electronically excited singlet and triplet states and oscillator strengths for electronic transitions from the electronic ground state. PMID:27351464

  12. Measurement of Gas and Aerosol Phase Absorption Spectra across the Visible and Near-IR Using Supercontinuum Photoacoustic Spectroscopy.

    PubMed

    Radney, James G; Zangmeister, Christopher D

    2015-07-21

    We demonstrate a method to measure the absorption spectra of gas and aerosol species across the visible and near-IR (500 to 840 nm) using a photoacoustic (PA) spectrometer and a pulsed supercontinuum laser source. Measurements of gas phase absorption spectra were demonstrated using H2O(g) as a function of relative humidity (RH). The measured absorption intensities and peak shapes were able to be quantified and compared to spectra calculated using the 2012 High Resolution Transmission (HITRAN2012) database. Size and mass selected nigrosin aerosol was used to measure absorption spectra across the visible and near-IR. Spectra were measured as a function of aerosol size/mass and show good agreement to Mie theory calculations. Lastly, we measured the broadband absorption spectrum of flame generated soot aerosol at 5% and 70% RH. For the high RH case, we are able to quantifiably separate the soot and water absorption contributions. For soot, we observe an enhancement in the mass specific absorption cross section ranging from 1.5 at 500 nm (p < 0.01) to 1.2 at 840 nm (p < 0.2) and a concomitant increase in the absorption Ångström exponent from 1.2 ± 0.4 (5% RH) to 1.6 ± 0.3 (70% RH). PMID:26098142

  13. Trigonometric Polynomials For Estimation Of Spectra

    NASA Technical Reports Server (NTRS)

    Greenhall, Charles A.

    1990-01-01

    Orthogonal sets of trigonometric polynomials used as suboptimal substitutes for discrete prolate-spheroidal "windows" of Thomson method of estimation of spectra. As used here, "windows" denotes weighting functions used in sampling time series to obtain their power spectra within specified frequency bands. Simplified windows designed to require less computation than do discrete prolate-spheroidal windows, albeit at price of some loss of accuracy.

  14. New atlas of IR solar spectra

    NASA Technical Reports Server (NTRS)

    Goldman, A.; Blatherwick, R. D.; Murcray, F. H.; Vanallen, J. W.; Bradford, C. M.; Cook, G. R.; Murcray, D. G.

    1980-01-01

    Over 4500 absorption lines have been marked on the spectra and the corresponding line positions tabulated. The associated absorbing telluric or solar species for more than 90% of these lines have been identified and only a fraction of the unidentified lines have peak absorptions greater than a few percent. The high resolution and the low Sun spectra greatly enhance the sensitivity limits for identification of trace constituents.

  15. Establishment of the spectra of kinetic turbulence

    NASA Technical Reports Server (NTRS)

    Bolshov, L. A.; Dykhne, A. M.; Kiselev, V. P.; Pergament, A. K.

    1979-01-01

    An analysis of kinetic equations describing the establishment of Langmuir turbulence spectra is presented. Secondary turbulence occurs where stationary distribution consists of many peaks. The position of peaks is established and their amplitudes complete undamped oscillations. It is pointed out that establishing spectra can occur only during adiabatic inclusion of pumping. It is significant here that the adiabiatic condition is more rigid than the ordinary by several hundred times.

  16. Diffuse emission and pathological Seyfert spectra

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.

    1995-01-01

    In this annual ROSAT status report, the diffuse emission and spectra from Seyfert galaxies are examined. Three papers are presented and their contents include the soft x-ray properties and spectra of a binary millisecond pulsar, the PSPC and HRI observations of a Starburst/Seyfert 2 Galaxy, and an analysis of the possibility of x-ray luminous starbursts in the Einstein Medium Sensitivity Survey.

  17. Tilted cranking classification of multiband spectra

    NASA Astrophysics Data System (ADS)

    Frauendorf, S.; May, F. R.

    1992-06-01

    The existence of TDHF-solutions rotating uniformly about a nonprincipal axis of the deformed axial potential is demonstrated. The solutions represent Delta(I) = 1 bands. Self consistency and symmetry are discussed. The transformation of experimental spectra to the rotating frame of reference is introduced. Excitation spectra at high spin are calculated and found to agree well with recent data on Er-163 and Hf-174.

  18. EUV reticle inspection with a 193nm reticle inspector

    NASA Astrophysics Data System (ADS)

    Broadbent, William; Inderhees, Gregg; Yamamoto, Tetsuya; Lee, Isaac; Lim, Phillip

    2013-06-01

    The prevailing industry opinion is that EUV Lithography (EUVL) will enter High Volume Manufacturing (HVM) in the 2015 - 2017 timeframe at the 16nm HP node. Every year the industry assesses the key risk factors for introducing EUVL into HVM - blank and reticle defects are among the top items. To reduce EUV blank and reticle defect levels, high sensitivity inspection is needed. To address this EUV inspection need, KLA-Tencor first developed EUV blank inspection and EUV reticle inspection capability for their 193nm wavelength reticle inspection system - the Teron 610 Series (2010). This system has become the industry standard for 22nm / 3xhp optical reticle HVM along with 14nm / 2xhp optical pilot production; it is further widely used for EUV blank and reticle inspection in R and D. To prepare for the upcoming 10nm / 1xhp generation, KLA-Tencor has developed the Teron 630 Series reticle inspection system which includes many technical advances; these advances can be applied to both EUV and optical reticles. The advanced capabilities are described in this paper with application to EUV die-to-database and die-to-die inspection for currently available 14nm / 2xhp generation EUV reticles. As 10nm / 1xhp generation optical and EUV reticles become available later in 2013, the system will be tested to identify areas for further improvement with the goal to be ready for pilot lines in early 2015.

  19. Analysis of reflectance spectra from hyperspectral images of poultry carcasses for fecal and ingesta detection

    NASA Astrophysics Data System (ADS)

    Windham, William R.; Lawrence, Kurt C.; Park, Bosoon; Smith, Doug P.; Poole, Gavin

    2002-11-01

    Identification and separation of poultry carcasses contaminated by feces and/or crop ingesta are very important to protect the consumer from a potential source of food poisoning. A transportable hyperspectral imaging system was developed to detect fecal and ingesta contamination on the surface of poultry carcasses. Detection algorithms used with the imaging system were developed from visible/near infrared monochromator spectra and with contaminates from birds fed a corn/soybean meal diet. The objectives of this study were to investigate using regions of interest reflectance spectra from hyperspectral images to determine optimal wavelengths for fecal detection algorithms from images of birds fed corn, wheat and milo diets. Spectral and spatial data between 400 and 900 nm with a 1.0 nm spectral resolution were acquired from uncontaminated and fecal and ingesta contaminated poultry carcasses. Regions of interest (ROIs) were defined for fecal and ingesta contaminated and uncontaminated skin (i.e. breast, thigh, and wing). Average reflectance spectra of the ROIs were extracted for analysis. Reflectance spectra of contaminants and uncontaminated skin differed. Spectral data pre-processing treatments with a single-term, linear regression program to select wavelengths for optimum calibration coefficients to detect contamination were developed. Fecal and ingesta detection models, specifically a quotient of 2 and/or 3-wavelengths was 100% successful in classification of contaminates.

  20. All-fibre ytterbium laser tunable within 45 nm

    SciTech Connect

    Abdullina, S R; Babin, S A; Vlasov, A A; Kablukov, S I; Shelemba, I S; Kurkov, A S

    2007-12-31

    A tunable ytterbium-doped fibre laser is fabricated. The laser is tuned by using a tunable fibre Bragg grating (FBG) as a selecting intracavity element. The laser is tunable within 45 nm (from 1063 to 1108 nm) and emits {approx}6 W in the line of width {approx}0.15 nm, the output power and linewidth being virtually invariable within the tuning range. The method is proposed for synchronous tuning the highly reflecting and output FBGs, and a tunable ytterbium all-fibre laser is built. (lasers)

  1. Spectropolarimetry of Atomic and Molecular Lines near 4135 nm

    NASA Astrophysics Data System (ADS)

    Penn, Matthew James; Uitenbroek, Han; Clark, Alan; Coulter, Roy; Goode, Phil; Cao, Wenda

    2016-10-01

    New spatially scanned spectropolarimetry sunspot observations are made of photospheric atomic and molecular absorption lines near 4135 nm. The relative splittings among several atomic lines are measured and shown to agree with values calculated with configuration interaction and intermediate coupling. Large splitting is seen in a line identified with Fe i at 4137 nm, showing multiple Stokes V components and an unusual linear polarization. This line will be a sensitive probe of quiet-Sun magnetic fields, with a magnetic sensitivity of 2.5 times higher than that of the well-known 1565 nm Fe i line.

  2. Spectropolarimetry of Atomic and Molecular Lines near 4135 nm

    NASA Astrophysics Data System (ADS)

    Penn, Matthew James; Uitenbroek, Han; Clark, Alan; Coulter, Roy; Goode, Phil; Cao, Wenda

    2016-09-01

    New spatially scanned spectropolarimetry sunspot observations are made of photospheric atomic and molecular absorption lines near 4135 nm. The relative splittings among several atomic lines are measured and shown to agree with values calculated with configuration interaction and intermediate coupling. Large splitting is seen in a line identified with Fe uc(i) at 4137 nm, showing multiple Stokes V components and an unusual linear polarization. This line will be a sensitive probe of quiet-Sun magnetic fields, with a magnetic sensitivity of 2.5 times higher than that of the well-known 1565 nm Fe uc(i) line.

  3. 80 nm tunable DBR-free semiconductor disk laser

    NASA Astrophysics Data System (ADS)

    Yang, Z.; Albrecht, A. R.; Cederberg, J. G.; Sheik-Bahae, M.

    2016-07-01

    We report a widely tunable optically pumped distributed Bragg reflector (DBR)-free semiconductor disk laser with 6 W continuous wave output power near 1055 nm when using a 2% output coupler. Using only high reflecting mirrors, the lasing wavelength is centered at 1034 nm and can be tuned up to a record 80 nm by using a birefringent filter. We attribute such wide tunability to the unique broad effective gain bandwidth of DBR-free semiconductor disk lasers achieved by eliminating the active mirror geometry.

  4. Protein Helical Structure Determination Using CD Spectroscopy for Solutions with Strong Background Absorbance from 190-230 nm

    PubMed Central

    Wei, Yang; Thyparambil, Aby A.; Latour, Robert A.

    2014-01-01

    Conventional empirical methods for the quantification of the helical content of proteins in solution using circular dichroism (CD) primarily rely on spectral data acquired between wavelengths of 190 to 230 nm. The presence of chemical species in a protein solution with strong absorbance within this range can interfere with the ability to use these methods for the determination of the protein’s helical structure. The objective of this research was to overcome this problem by developing a method for CD spectral analysis that relies on spectral features above this wavelength range. In this study, we determined that the slopes of CD spectra acquired over the 230 to 240 nm region strongly correlate with the helix contents including α-helix and 310-helix of protein as determined using conventional CD algorithms that rely on wavelengths between 190-230 nm. This approach (i.e., the 230-240 nm slope method) is proposed as an effective method to determine the helix content within proteins in the presence of additives such as detergents or denaturants with high absorbance of wavelengths up to 230 nm. PMID:25308773

  5. The Soil Spectroscopy Group and the development of a global soil spectral library

    NASA Astrophysics Data System (ADS)

    Rossel, R. Viscarra Rossel; Soil Spectroscopy Group

    2009-04-01

    This collaboration aims to develop a global soil spectral library and to establish a community of practice for soil spectroscopy. This will help progress soil spectroscopy from an almost purely research tool to a more widely adopted and useful technique for soil analysis, proximal soil sensing, soil monitoring and digital soil mapping. The initiative started in April 2008 with a proposal for the project to be conducted in a number of stages to investigate the following topics: Global soil diversity and variation can be characterised using diffuse reflectance spectra. Soil spectral calibrations can be used to predict soil properties globally. Soil spectroscopy can be a useful tool for digital soil mapping. Currently, the soil spectral library is being developed using legacy soil organic carbon (OC) and clay content data and vis-NIR (350-2500 nm) spectra, but in future we aim to include other soil properties and mid-IR (2500-25000 nm) spectra. The group already has more than 40 collaborators from six continents and 20 countries and the library consists of 5223 spectra from 43 countries. The library accounts for spectra from approximately only 22% of the world's countries, some of which are poorly represented with only very few spectra. We would like to encourage participation from as many countries as possible, particularly, we would like contributions from counties in Central and South America, Mexico, Canada, Russia and countries in Eastern Europe, Africa and Asia. We are missing a lot of countries and for some, e.g. China we have only very few data! Do you want to join the group and contribute spectra to the global library? The requirements for contributing spectra to the global library are as follows: Spectra collected in the 350-2500 nm range every 1 nm. At least soil OC and clay content data but also any other soil chemical, physical, biological and mineralogical data, noting which analytical techniques were used. Coordinates (in WGS84 format) for each sample

  6. H{sub 2} and D{sub 2} in intense sub-picosecond laser pulses: Photoelectron spectroscopy at 1053 and 527 nm

    SciTech Connect

    Rottke, H.; Ludwig, J.; Sandner, W.

    1996-09-01

    We report multiphoton ionization experiments on H{sub 2} and D{sub 2} molecules at 1053- and 526.5-nm excitation wavelengths in the intensity range 5{times}10{sup 13}{endash}5{times}10{sup 14} W/cm{sup 2}. The intensity dependence of the total ion yield, the dissociation fraction, and the photoelectron spectrum is investigated. At 1053 nm we find a strong isotope effect in the dissociation fraction, whereas at 526.5 nm no such effect is observed. Up to 1{times}10{sup 14} W/cm{sup 2} the photoelectron spectrum at 526.5 nm is dominated by resonant ionization processes via Rydberg states of the molecules. They are shifted into resonance at intensities above {approximately}10{sup 13} W/cm{sup 2}. The spectra show that the potential energy curves of the resonant states must have a shape very similar to the corresponding ionic ones. They are therefore mainly determined by the dipole coupling between the ion core orbitals 1{ital s}{sigma}{sub {ital g}} and 2{ital p}{sigma}{sub {ital u}}. At 1053 nm two photoionization regimes are observed: the multiphoton regime with Keldysh parameter {gamma}{gt}1 showing resonance ionization structures, and the tunnel regime ({gamma}{lt}1) at high intensity. The isotope effect in the dissociation fraction at 1053 nm has no influence on the shape of the corresponding photoelectron spectra at this wavelength. {copyright} {ital 1996 The American Physical Society.}

  7. Improving laser damage resistance of 355 nm high-reflective coatings by co-evaporated interfaces.

    PubMed

    Xing, Huanbin; Zhu, Meiping; Chai, Yingjie; Yi, Kui; Sun, Jian; Cui, Yun; Shao, Jianda

    2016-03-15

    355 nm high-reflective multilayer coatings with or without coevaporated interfaces (CEIs) were prepared by electron beam evaporation under the same deposition condition. Their transmission spectra, surface roughness, and mechanical stress properties were evaluated. Elemental composition analysis of the multilayer interfaces was performed using x-ray photoelectron spectroscopy, and laser-induced damage thresholds were obtained in both 1-on-1 and 300-on-1 testing modes. The coatings with CEIs reveal a lower mechanical stress and a higher laser damage resistance when irradiated with high laser fluence, and the corresponding damage modeling indicates that CEIs can significantly decrease defect density. The resulting damage morphologies show that CEI coatings can significantly suppress coating delamination and exhibit a "bulk-like" damage behavior, demonstrating better damage performance against high-power lasers. PMID:26977682

  8. Photodissociation and Photoionization of Propanaldehyde at 355 nm. Theory and experiment.

    NASA Astrophysics Data System (ADS)

    Cisneros, Carmen; Muñoz-Rugeles, Leonardo; Guerrero, Alfonso; Alvarez, Ignacio

    2013-05-01

    Propanaldehyde is a large component in the atmosphere, finding in concentrations around 1-2 × 1010 molecules/cm3, motivating the characterization of photodissociation and photoionization dynamics by UV multiphoton absorption. In this work we present the study of photodissociation and photoionization dynamics by multiphoton absorption with 355 nm wavelength photons, using time of flight spectrometry in reflectron mode, R-TOF, and calculations of potential energy surfaces for the principal reaction coordinate using time dependent density functional theory, TD-DFT. The experimental and theoretical results suggest that the characteristics observed in the R-TOF spectra come from the generation of free radicals, by two photon absorption, that later are ionized by multiphoton absorption. This work is supported by grants DGAPA-UNAM IN-107-912, IN-102613 and CONACyT 165410.

  9. 157 nm Photodissociation of a Complete Set of Dipeptide Ions Containing C-Terminal Arginine

    NASA Astrophysics Data System (ADS)

    He, Yi; Webber, Nathaniel; Reilly, James P.

    2013-05-01

    Twenty singly-charged dipeptide ions with C-terminal arginine were photodissociated with 157 nm light and their tandem mass spectra recorded. Many of the small product ions that were observed are standard peptide fragments that have been commonly seen in VUV photodissociation studies. However, the study of a library of dipeptides containing all 20 N-terminal amino acids enabled the recognition of trends associated with the occurrence of w-, v-, and immonium ions, the observation of competition between forming N- and C-terminal fragments in dipeptide RR, and the identification of some unusual fragment ions appearing at masses of 183, 187, 196, and 197 Da. A highly accurate internal calibration of the photodissociation TOF-TOF data enabled molecular formulae for these four product ions to be derived. Their proposed structures reflect the rather high-energy nature of this fragmentation phenomenon.

  10. 1-nm-thick graphene tri-layer as the ultimate copper diffusion barrier

    SciTech Connect

    Nguyen, Ba-Son; Lin, Jen-Fin

    2014-02-24

    We demonstrate the thinnest ever reported Cu diffusion barrier, a 1-nm-thick graphene tri-layer. X-ray diffraction patterns and Raman spectra show that the graphene is thermally stable at up to 750 °C against Cu diffusion. Transmission electron microscopy images show that there was no inter-diffusion in the Cu/graphene/Si structure. Raman analyses indicate that the graphene may have degraded into a nanocrystalline structure at 750 °C. At 800 °C, the perfect carbon structure was damaged, and thus the barrier failed. The results of this study suggest that graphene could be the ultimate Cu interconnect diffusion barrier.

  11. Surface modification during Nd:YAG (1064 nm) pulsed laser cleaning of organic fibrous materials

    NASA Astrophysics Data System (ADS)

    Strlič, Matija; Kolar, Jana; Šelih, Vid-Simon; Marinček, Marko

    2003-02-01

    Formation of yellow chromophores on artificially soiled surfaces of cellulose sheets, rag paper, linen, cotton, wool and silk during Nd:YAG (1064 nm) pulsed laser cleaning was followed using Vis and FTIR diffuse reflectance spectrometry. Content of reducing carbonyl groups and changes in FTIR reflectance spectra of cellulose are indicative of surface chemical modifications typical of thermal degradation at elevated temperatures. Two types of soiling were used: well-characterised natural dust and carbon powder and no difference in laser-induced formation of chromophores on material surface was observed at low deposit densities. The influence of laser fluence and number of repetitions was studied and a single pulse of a higher fluence (1 J cm -1) is in general more advisable. No bleaching of the chromophores formed was noticed after repeated treatments.

  12. Electro-optic dual-comb interferometry over 40  nm bandwidth.

    PubMed

    Durán, Vicente; Andrekson, Peter A; Torres-Company, Víctor

    2016-09-15

    Dual-comb interferometry is a measurement technique that uses two laser frequency combs to retrieve complex spectra in a line-by-line basis. This technique can be implemented with electro-optic frequency combs, offering intrinsic mutual coherence, high acquisition speed and flexible repetition-rate operation. A challenge with the operation of this kind of frequency comb in dual-comb interferometry is its limited optical bandwidth. Here, we use coherent spectral broadening and demonstrate electro-optic dual-comb interferometry over the entire telecommunications C band (200 lines covering ∼40  nm, measured within 10 μs at 100 signal-to-noise ratio per spectral line). These results offer new prospects for electro-optic dual-comb interferometry as a suitable technology for high-speed broadband metrology, for example in optical coherence tomography or coherent Raman microscopy.

  13. Electro-optic dual-comb interferometry over 40  nm bandwidth.

    PubMed

    Durán, Vicente; Andrekson, Peter A; Torres-Company, Víctor

    2016-09-15

    Dual-comb interferometry is a measurement technique that uses two laser frequency combs to retrieve complex spectra in a line-by-line basis. This technique can be implemented with electro-optic frequency combs, offering intrinsic mutual coherence, high acquisition speed and flexible repetition-rate operation. A challenge with the operation of this kind of frequency comb in dual-comb interferometry is its limited optical bandwidth. Here, we use coherent spectral broadening and demonstrate electro-optic dual-comb interferometry over the entire telecommunications C band (200 lines covering ∼40  nm, measured within 10 μs at 100 signal-to-noise ratio per spectral line). These results offer new prospects for electro-optic dual-comb interferometry as a suitable technology for high-speed broadband metrology, for example in optical coherence tomography or coherent Raman microscopy. PMID:27628354

  14. Pulse shaping control of CH3I multiphoton ionization at 540 nm

    NASA Astrophysics Data System (ADS)

    Gitzinger, Gregory; Loriot, Vincent; Bañares, Luis; de Nalda, Rebeca

    2014-06-01

    A pulse shaping control experiment on multiphoton ionization of the methyl iodide (CH3I) molecule is reported. A range of phase masks were applied in the Fourier plane of a 4f pulse shaper containing a spatial light modulator, causing spectro-temporal modulation in the 540 nm pulses synthesized in an optical parametric amplifier. The ionization process was studied through velocity map imaging of outgoing photoelectrons. Four main ionization channels were identified, with relative yields that are dependent on the pulse shape applied, indicating that the ionization routes can be steered through light manipulation to some extent. The main mechanism for control seems to derive from peak intensity effects, but some features observed in the photoelectron spectra defy this explanation. The role of resonances at the three-photon level is discussed.

  15. Parallel-type C+L band hybrid amplifier pumped by 1480 nm laser diodes

    NASA Astrophysics Data System (ADS)

    Liaw, S.-K.; Huang, C.-K.; Hsiao, Y.-L.

    2008-07-01

    A parallel-type, dispersion compensating C+L band erbium-doped fiber amplifier/Raman fiber amplifier is constructed by sharing a common 1480-nm pump source. The gain spectra of C+L band are flattened by optimally dividing the pump power ratio to 1:29 for EDFA and RFA, respectively. In a signal input power of -20 dBm, the average gain is 14 dB for the C-band EDFA and 13.6 dB for the L-band RFA when a pump reflector is used to recycle the residual pump power in L-band. The noise figure value ranges from 4.6 to 6.5 dB and the polarization dependent gain is less than 0.14 dB.

  16. Hyperfine structure and isotope shifts in 733.2 nm mixed forbidden line of Pb I

    NASA Astrophysics Data System (ADS)

    Wąsowicz, T. J.; Drozdowski, R.; Kwela, J.

    2007-05-01

    Studies of the hyperfine structure and isotope shifts in 733.2 nm mixed (M1+E2) multipole line of Pb I are presented. As a light source the electrodeless discharge tube was used. The high resolution spectral apparatus consisted of a silver coated Fabry-Perot etalon and a grating spectrograph combined with a CCD camera used as a detector. In the analysis of the spectra a computer simulation technique was used. The experiments with the isotope 207Pb yielded the hyperfine structure splitting constant A for the 3P1 and 1D2 levels of the 6s26p2 ground configuration. In the experiment with natural lead the isotope shifts between four stable isotopes (204, 206, 207, 208) were measured.

  17. Pressure effects on the Cl 2 (D'-A') transition at 258 nm

    NASA Astrophysics Data System (ADS)

    Nee, J. B.; Hubinger, S.

    1996-11-01

    UV emission at 258 nm from the transition of Cl 2(D'-A') was investigated by photoexcitation of the Rydberg states at pressures between 1 and 100 Torr. The intensity of the UV fluorescence produced was increased by a factor of two when the pressure of the buffer gas N 2 was increased from 1 to 20 Torr. Characteristic pressures for quenching and fluorescence enhancement were derived. Kinetic studies revealed the mechanism of the interstate transitions about the generation of the D'-A' transition. A vibrational state redistribution in the excitation spectra for the 2 1Σu+ state at high pressure was observed. The cause of this is explained in terms of state-dependent quenching.

  18. Electro-optic dual-comb interferometry over 40 nm bandwidth

    NASA Astrophysics Data System (ADS)

    Durán, Vicente; Andrekson, Peter A.; Torres-Company, Víctor

    2016-09-01

    Dual-comb interferometry is a measurement technique that uses two laser frequency combs to retrieve complex spectra in a line-by-line basis. This technique can be implemented with electro-optic frequency combs, offering intrinsic mutual coherence, high acquisition speed and flexible repetition-rate operation. A challenge with the operation of this kind of frequency comb in dual-comb interferometry is its limited optical bandwidth. Here, we use coherent spectral broadening and demonstrate electro-optic dual-comb interferometry over the entire telecommunications C band (200 lines covering ~ 40 nm, measured within 10 microseconds at 100 signal-to-noise ratio per spectral line). These results offer new prospects for electro-optic dual-comb interferometry as a suitable technology for high-speed broadband metrology, for example in optical coherence tomography or coherent Raman microscopy.

  19. Discriminating model for diagnosis of basal cell carcinoma and melanoma in vitro based on the Raman spectra of selected biochemicals

    NASA Astrophysics Data System (ADS)

    Silveira, Landulfo; Silveira, Fabrício Luiz; Bodanese, Benito; Zângaro, Renato Amaro; Pacheco, Marcos Tadeu T.

    2012-07-01

    Raman spectroscopy has been employed to identify differences in the biochemical constitution of malignant [basal cell carcinoma (BCC) and melanoma (MEL)] cells compared to normal skin tissues, with the goal of skin cancer diagnosis. We collected Raman spectra from compounds such as proteins, lipids, and nucleic acids, which are expected to be represented in human skin spectra, and developed a linear least-squares fitting model to estimate the contributions of these compounds to the tissue spectra. We used a set of 145 spectra from biopsy fragments of normal (30 spectra), BCC (96 spectra), and MEL (19 spectra) skin tissues, collected using a near-infrared Raman spectrometer (830 nm, 50 to 200 mW, and 20 s exposure time) coupled to a Raman probe. We applied the best-fitting model to the spectra of biochemicals and tissues, hypothesizing that the relative spectral contribution of each compound to the tissue Raman spectrum changes according to the disease. We verified that actin, collagen, elastin, and triolein were the most important biochemicals representing the spectral features of skin tissues. A classification model applied to the relative contribution of collagen III, elastin, and melanin using Euclidean distance as a discriminator could differentiate normal from BCC and MEL.

  20. Efficient laser operation of Nd3+:Lu2O3 at various wavelengths between 917 nm and 1463 nm

    NASA Astrophysics Data System (ADS)

    von Brunn, P.; Heuer, A. M.; Fornasiero, L.; Huber, G.; Kränkel, C.

    2016-08-01

    Even though the first Nd3+-doped sesquioxide lasers have been realized more than 50 years ago, up to now no reports on efficient laser operation of Nd3+:doped sesquioxides can be found. In this work, we review the favorable spectroscopic properties of the sesquioxide Nd3+:Lu2O3 in terms of ground state absorption, stimulated emission, and excited state absorption cross sections as well as the upper level lifetime. Making use of these properties, we achieved efficient laser performance on eight different laser transitions in the wavelength range between 917 nm and 1463 nm under Ti:sapphire laser pumping using state-of-the-art HEM-grown Nd3+:Lu2O3 crystals with good optical quality. At the strongest transition around 1076 nm we determined a slope efficiency of 69%, which represents the highest efficiency ever obtained for a Nd3+-doped sesquioxide. Furthermore, we could generate watt level output powers and high slope efficiencies for seven other transitions. Lasers at 917 nm, 1053 nm, 1108 nm and 1463 nm were realized for the first time and the latter represents one of the longest laser wavelengths obtained on the 4F3/2  →  4I13/2 transition in Nd3+-doped materials.

  1. Compact frequency-quadrupled pulsed 1030nm fiber laser

    NASA Astrophysics Data System (ADS)

    McIntosh, Chris; Goldberg, Lew; Cole, Brian; DiLazaro, Tom; Hays, Alan D.

    2016-03-01

    A compact 1030nm fiber laser for ultraviolet generation at 257.5nm is presented. The laser employs a short length of highly-doped, large core (20μm), coiled polarization-maintaining ytterbium-doped double-clad fiber pumped by a wavelength-stabilized 975nm diode. It is passively Q-switched via a Cr4+:YAG saturable absorber and generates 2.4W at 1030nm in a 110μJ pulse train. Lithium triborate (LBO) and beta-barium borate (BBO) are used to achieve 325mW average power at the fourth harmonic. The laser's small form factor, narrow linewidth and modest power consumption are suitable for use in a man-portable ultraviolet Raman explosives detection system.

  2. 980 nm narrow linewidth Yb-doped phosphate fiber laser

    NASA Astrophysics Data System (ADS)

    Li, Pingxue; Yao, Yifei; Hu, Haowei; Chi, Junjie; Yang, Chun; Zhao, Ziqiang; Zhang, Guangju

    2014-12-01

    A narrow-linewidth ytterbium (Yb)-doped phosphate fiber laser based on fiber Bragg grating (FBG) operating around 980 nm is reported. Two different kinds of cavity are applied to obtain the 980 nm narrow-linewidth output. One kind of the cavity consists of a 0.35 nm broadband lindwidth high-reflection FBG and the Yb-doped phosphate fiber end with 0° angle, which generates a maximum output power of 25 mW. The other kind of resonator is composed of a single mode Yb-doped phosphate fiber and a pair of FBGs. Over 10.7 mW stable continuous wave are obtained with two longitudinal modes at 980 nm. We have given a detailed analysis and discussion for the results.

  3. Absolute measurement of F2-laser power at 157 nm

    SciTech Connect

    Kueck, Stefan; Brandt, Friedhelm; Kremling, Hans-Albert; Gottwald, Alexander; Hoehl, Arne; Richter, Mathias

    2006-05-10

    We report a comparison of laser power measurements at the F2-laser wavelength oaf nm made at two facilities of the Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute. At the PTB laboratory at the electron storage ring BESSY II in Berlin, the scale for laser power was directly traced to a cryogenic radiometer operating at 157 nm, whereas at the PTB laser radiometry facility in Braunschweig the calibration of transfer detectors was performed with a newly developed standard for laser power at 157 nm, which is traceable in several steps to a cryogenic radiometer operating at 633 nm. The comparison was performed under vacuum conditions with laser pulse energies of?10 {mu}J, however with different average powers because different primary standard radiometers were used. The relative deviation for the responsivity of the transfer detector was 4.8% and thus within the combined standard uncertainty.

  4. Immersion and 32nm lithography: now and future

    NASA Astrophysics Data System (ADS)

    Kameyama, Masaomi; McCallum, Martin

    2007-12-01

    The amazing growth of the semiconductor industry over the past decades has been supported, and in many cases driven, by miniaturization of devices. Behind this has been one strong backbone - lithography. In the 1970's, devices had geometries of several micrometers, but now we are about to enter 45nm device pre-production and shortly after move it into volume-production. Immersion lithography, although having a short development time, is already in production and will become the primary technology driver. What we need to do now is identify the solutions for 32nm lithography. There are several candidates for 32nm lithography, such as EUVL, High Index Immersion and Double Patterning / Double Exposure. Other more esoteric technologies such as nanoimprint and maskless lithography have also been mentioned. In this paper, the present status of Immersion lithography will be reviewed and each of the 32nm candidates are reviewed.

  5. Determination of complex index of immersion liquids at 193 nm

    NASA Astrophysics Data System (ADS)

    Stehle, Jean-Louis; Piel, Jean-Philippe; Campillo-Carreto, Jose

    2006-03-01

    The next nodes in immersion lithography will require the scanners to use the 193 nm ArF* laser line with a very large numerical aperture and a liquid between the optics and the resist. (1) Immersion lithography at 193 nm requests very specific parameters for the fluid. The first generation is using the deionized Water (DIW) very pure and not recycled, but when a new optical material for the last lens will be available with a refractive index (RI) larger than 1.85, a higher refractive index fluid could be used, enabling second and maybe third generation of immersion lithography at 193 nm. So the 45 and maybe the 32 nm nodes could be covered with this high Index fluids (HIF).

  6. The Missing Solar Irradiance Spectrum: 1 to 7 nm

    NASA Astrophysics Data System (ADS)

    Sojka, J. J.; Lewis, M.; David, M.; Schunk, R. W.; Woods, T. N.; Eparvier, F. G.; Warren, H. P.

    2015-12-01

    During large X-class flares the Earth's upper atmospheric E-region responds immediately to solar photons in the 1 to 7 nm range. The response can change the E-region density by factors approaching 10, create large changes in conductivity, and plague HF communications. GOES-XRS provide 0.1 to 0.8 nm and a 0.05 to 0.4 nm integral channels; SOHO-SEM provided a 0 to 50 nm irradiance; TIMED and SORCE-XPS diode measurements also integrated down to 0.1 nm; and most recently SDO-EVE provided a 0.1 to 7 nm irradiance. For atmospheric response to solar flares the cadence is also crucial. Both GOES and SDO provided integral measurements at 10 seconds or better. Unfortunately these measurements have failed to capture the 1 to 7 nm spectral changes that occur during flares. It is these spectral changes that create the major impact since the ionization cross-section of the dominant atmospheric species, N2 and O2, both contain step function changes in the cross-sections. Models of the solar irradiance over this critical wavelength regime have suffered from the need to model the spectral variability based on incomplete measurements. The most sophisticated empirical model FISM [Chamberlin et al., 2008] used 1 nm spectral binning and various implementations of the above integral measurements to describe the 1 to 7 nm irradiance. Since excellent solar observations exist at other wavelengths it is possible to construct an empirical model of the solar atmosphere and then use this model to infer the spectral distribution at wavelengths below 5 nm. This differential emission measure approach has been used successfully in other contexts [e.g., Warren, 2005, Chamberlin et al., 2009]. This paper contrasts the broadband versus spectrally resolved descriptions of the incoming irradiance that affects the upper atmospheric E-layer. The results provide a prescription of what wavelength resolution would be needed to adequately measure the incoming solar irradiance in the 1 to 7 nm range.

  7. Low-k/copper integration scheme suitable for ULSI manufacturing from 90nm to 45nm nodes

    NASA Astrophysics Data System (ADS)

    Nogami, T.; Lane, S.; Fukasawa, M.; Ida, K.; Angyal, M.; Chanda, K.; Chen, F.; Christiansen, C.; Cohen, S.; Cullinan, M.; Dziobkowski, C.; Fitzsimmons, J.; Flaitz, P.; Grill, A.; Gill, J.; Inoue, K.; Klymko, N.; Kumar, K.; Labelle, C.; Lane, M.; Li, B.; Liniger, E.; Madon, A.; Malone, K.; Martin, J.; McGahay, V.; McLaughlin, P.; Melville, I.; Minami, M.; Molis, S.; Nguyen, S.; Penny, C.; Restaino, D.; Sakamoto, A.; Sankar, M.; Sherwood, M.; Simonyi, E.; Shimooka, Y.; Tai, L.; Widodo, J.; Wildman, H.; Ono, M.; McHerron, D.; Nye, H.; Davis, C.; Sankaran, S.; Edelstein, D.; Ivers, T.

    2005-11-01

    This paper discusses low-k/copper integration schemes which has been in production in the 90 nm node, have been developed in the 65 nm node, and should be taken in the 45 nm node. While our baseline 65 nm BEOL process has been developed by extension and simple shrinkage of our PECVD SiCOH integration which has been in production in the 90 nm node with our SiCOH film having k=3.0, the 65 nm SiCOH integration has two other options to go to extend to lower capacitance. One is to add porosity to become ultra low-k (ULK). The other is to stay with low-k SiCOH, which is modified to have a "lower-k". The effective k- value attained with the lower-k (k=2.8) SiCOH processed in the "Direct CMP" scheme is very close to that with an ULK (k=2.5) SiCOH film built with the "Hard Mask Retention" scheme. This paper first describes consideration of these two damascene schemes, whose comparison leads to the conclusion that the lower-k SiCOH integration can have more advantages in terms of process simplicity and extendibility of our 90 nm scheme under certain assumptions. Then describing the k=2.8 SiCOH film development and its successful integration, damascene schemes for 45nm nodes are discussed based on our learning from development of the lower-k 65nm scheme. Capability of modern dry etchers to define the finer patterns, non-uniformity of CMP, and susceptibility to plasma and mechanical strength and adhesion of ULK are discussed as factors to hamper the applicability of ULK.

  8. Development of a cyclometalated iridium complex with specific intramolecular hydrogen-bonding that acts as a fluorescent marker for the endoplasmic reticulum and causes photoinduced cell death† †Electronic supplementary information (ESI) available: Detailed synthesis; photophysical data (Table S1); pH dependent phosphorescence lifetime of complex C2 (Table S2); crystallographic parameters of C2; selected bond distances and angles of C2 (Table S3); cyclic voltammetric data of complexes C1–C11 (Table S4); 1H NMR spectra of ligands and complexes (Fig. S1 and S3); ESI-MS spectra of ligands and complexes (Fig. S2 and S4); fluorescence spectra of the complexes in acetonitrile and at pH 4, 7 and 9, exponential decay curve of C2 (Fig. S5); pH dependent fluorescence spectrum of complexes C1–C11 (Fig. S6); DIC and confocal fluorescence images of live MCF7 cells not treated with C2 but exposed to photoirradiation at 405 nm for 30 min; the cells were treated with DCFDA and fluorescence images were obtained at 529 nm after excitation at 495 nm (Fig. S7). ESI videos 1 and 2. CCDC 967841. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4dt00845f Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file. Click here for additional data file.

    PubMed Central

    Mandal, Soumik; Poria, Dipak K.; Ghosh, Ritabrata

    2014-01-01

    Cyclometalated iridium complexes have important applications as phosphorescent probes for cellular imaging due to their photophysical properties. Moreover, these properties also make them potential candidates as photosensitizers for photodynamic therapy (PDT) of tumors and skin diseases. Treatment of MCF7 breast carcinoma cells with a heteroleptic phosphorescent cyclometalated iridium(iii) complex C2 followed by confocal imaging indicates that the complex selectively localizes and exhibits high fluorescence in the endoplasmic reticulum. In an unprecedented approach, systematic alteration of functional groups or the metal core in C2 to synthesize a series of iridium(iii) complexes (C1–C10) and an organometallic rhenium complex C11 with an imidazolyl modified phenanthroline ligand has indicated the functional groups and their interactions that are responsible for this selective localization. Remarkably, the exposure of the cells treated with C2 to irradiation at 405 nm for one hour led to membrane blebbing and cell death, demonstrating a photosensitizing property of the compound. PMID:25341053

  9. Spectra of plasmas of Ru, Rh, Pd and Mo produced with nanosecond and picosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Lokasani, Ragava; Long, Elaine; Sheridan, Paul; Hayden, Patrick; O'Reilly, Fergal; Dunne, Padraig; Endo, Akira; Limpouch, Jiri; O'Sullivan, Gerry

    2015-05-01

    This paper describes the extreme ultraviolet and soft x-ray emission recorded in the 2-12 nm region from Mo, Ru, Rh and Pd ions present in the laser produced plasmas. The spectra were found to be dominated by 3p-3d transitions in the 5-8 nm region, which shift slowly to shorter wavelengths with the increasing atomic number, and by 3d-4p and 3d-4f transitions at shorter wavelengths. These transitions, in a number of neighbouring ion stages, were distinguished by comparison with Cowan code calculations and previously reported data. The experimental results show that strong emission can be observed at the 6.X nm region for Ru, Rh and Pd plasmas.

  10. The synchronous fluorescence spectra character of hypocrellin B with type I collagen under irradiation

    NASA Astrophysics Data System (ADS)

    Zhang, Jucheng; Yan, Heping; Yang, Mengting; Feng, Yongzhen; Huang, Yun; Li, Lingmei; Liu, Wei

    2014-09-01

    The synchronous fluorescence (SF) technique can provide some useful information with the endogenous fluorophores in complex systems. The SF technique has been used in the characterization of the type I collagen in PBS solution (pH=7.4) and the photo-reaction of hypocrellin B (HB) with type I collagen in solution irradiation with the 475 nm light under saturated by oxygen, air and nitrogen respectively. The SF spectra show the peaks attribute to tyrosine residues (275 nm) and pyridinoline cross-link (325 nm) in collagen. The photo-induced reaction with HB causing the fluorescence quenching but no wavelength shift, this suggests the photo-reaction don't changing the microenvironment of PYD cross-link. The fluorescence quenching rate is faster than others when the solution saturated by oxygen. The results imply that the photo-induced reaction is oxygen dependence.

  11. Astronomical Implications from an Analysis of the Spectra of LEDs Used in Street Lighting

    NASA Astrophysics Data System (ADS)

    Pompea, Stephen M.; Delp, B.

    2013-01-01

    Using a Czerny-Turner spectrometer, 45 different types of outdoor lights were categorized. These spectra were used to determine how useful the light is to human eyes and how dark skies friendly these lights are. Dark skies friendly lighting means that little to no light shines above a right angle to the light, and should emit as little as possible below 500nm (green) wavelengths. The short wavelengths present a problem to astronomers in the form of Rayleigh scattering. The following criterion were used in selecting the best source for urban and rural lighting: color rendition measured by color rendering index (CRI), percentage of light scattered because it is emitted under 500 nm, and efficiency (lumens/watt). Analysis determined that the best option currently available is to add a 495-500 nm filter to existing and future white LEDs in cities.

  12. Exchange-coupling modified spin wave spectra in the perpendicularly magnetized Permalloy nanodot chain arrays

    NASA Astrophysics Data System (ADS)

    Dou, Jian; Hernandez, Sarah C.; Yu, Chengtao; Pechan, Michael J.; Folks, Liesl; Katine, Jordan A.; Carey, Matthew J.

    2010-05-01

    Spin wave spectra in exchange-coupled nanoscale dot chain arrays were studied using ferromagnetic resonance. The dot chain arrays, with dot diameters of 300 nm and thicknesses of 40 nm, coupled via Permalloy bridges of width ranging from 0 (no bridge) to 60 nm, were fabricated using e-beam lithography. In the perpendicularly magnetized isolated dots, multiple sharp ferromagnetic resonant peaks were observed, which are associated with the quantized in-plane wave vector due to the finite dot radius. These spectrum lines shift to higher fields for samples with wider bridges due to the increasing effective demagnetizing factor. For coupled dots, additional satellite peaks were observed at both sides of higher order spin wave modes and at the lower field side of the uniform mode. We show that these satellite peaks can be attributed to the excitation in each bridged dot and the interdot exchange coupling, respectively.

  13. High efficiency 1341 nm Nd:GdVO4 laser in-band pumped at 912 nm

    NASA Astrophysics Data System (ADS)

    Li, Y. L.; Liu, J. Y.; Zhang, Y. C.

    2012-03-01

    A high-efficiency 1341 nm Nd:GdVO4 laser in-band pumped at 912 nm is demonstrated for the first time. Using an all-solid-state Nd:GdVO4 laser operating at 912 nm as pump source, 542 mW output was obtained with 1.14 W absorbed pump power. The slope efficiency with respect to the absorbed pump power was 56.6%, and the fluctuation of the output power was better than 2.6% in the given 30 min. The beam quality factor M 2 is 1.15.

  14. Revisit pattern collapse for 14nm node and beyond

    NASA Astrophysics Data System (ADS)

    Yoshimoto, Kenji; Higgins, Craig; Raghunathan, Ananthan; Hartley, John G.; Goldfarb, Dario L.; Kato, Hirokazu; Petrillo, Karen; Colburn, Matthew E.; Schefske, Jeffrey; Wood, Obert; Wallow, Thomas I.

    2011-04-01

    In this study, we have analyzed new data sets of pattern collapse obtained from 300 mm wafers which were coated with a process-of-record (POR) EUV resist and exposed by an EUV Alpha-Demo tool (ADT) and a Vistec VB300 e-beam exposure tool. In order to minimize any processing effects on pattern collapse, the same POR EUV track process was applied to both exposures. A key metric of our analysis is the critical aspect ratio of collapse (CARC)1. We found that CARC of POR EUV resist decreases monotonically with spacing, in the range of ~1.8-2.2 at ~32-54 nm space (60-80 nm pitch) for EUV, and ~1.5-2.1 at ~16-50 nm space (~46-80 nm pitch) for e-beam. We also estimated an apparent Young's modulus of POR EUV resist by fitting a collapse model2 to the CARC data. The resulting modulus ~0.30 GPa was much smaller than the modulus of typical polymer glasses (~1.0-5.0 GPa). Our findings suggest that due to a significant decrease of resist mechanical properties and a sharp increase in capillary force, it will be challenging to maintain aspect ratios above 2.0 for sub-30 nm resist spacing (sub-60 nm pitches). For patterning at these dimensions, alternate processes and materials will become increasingly necessary, e.g. surfactant-based rinse solutions3 and other approaches.

  15. Defect inspection of imprinted 32 nm half pitch patterns

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; McMackin, Ian; Perez, Joseph; Sreenivasan, S. V.; Resnick, Douglas J.

    2008-10-01

    Step and Flash Imprint Lithography redefines nanoimprinting. This novel technique involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed leaving a patterned solid on the substrate. Compatibility with existing CMOS processes requires a mask infrastructure in which resolution, inspection and repair are all addressed. The purpose of this paper is to understand the limitations of inspection at half pitches of 32 nm and below. A 32 nm programmed defect mask was fabricated. Patterns included in the mask consisted of an SRAM Metal 1 cell, dense lines, and dense arrays of pillars. Programmed defect sizes started at 4 nm and increased to 48 nm in increments of 4 nm. Defects in both the mask and imprinted wafers were characterized scanning electron microscopy and the measured defect areas were calculated. These defects were then inspected using a KLA-T eS35 electron beam wafer inspection system. Defect sizes as small as 12 nm were detected, and detection limits were found to be a function of defect type.

  16. Electron beam inspection methods for imprint lithography at 32 nm

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; Sreenivasan, S. V.; Resnick, Douglas J.

    2009-01-01

    Step and Flash Imprint Lithography redefines nanoimprinting. This novel technique involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed leaving a patterned solid on the substrate. Compatibility with existing CMOS processes requires a mask infrastructure in which resolution, inspection and repair are all addressed. The purpose of this paper is to understand the limitations of inspection at half pitches of 32 nm and below. A 32 nm programmed defect mask was fabricated. Patterns included in the mask consisted of an SRAM Metal 1 cell, dense lines, and dense arrays of pillars. Programmed defect sizes started at 4 nm and increased to 48 nm in increments of 4 nm. Defects in both the mask and imprinted wafers were characterized scanning electron microscopy and the measured defect areas were calculated. These defects were then inspected using a KLA-T eS35 electron beam wafer inspection system. Defect sizes as small as 12 nm were detected, and detection limits were found to be a function of defect type.

  17. Magneto-optical trap for metastable helium at 389 nm

    SciTech Connect

    Koelemeij, J.C.J.; Stas, R.J.W.; Hogervorst, W.; Vassen, W.

    2003-05-01

    We have constructed a magneto-optical trap (MOT) for metastable triplet helium atoms utilizing the 2 {sup 3}S{sub 1}{yields}3 {sup 3}P{sub 2} line at 389 nm as the trapping and cooling transition. The far-red-detuned MOT (detuning {delta}=-41 MHz) typically contains few times 10{sup 7} atoms at a relatively high ({approx}10{sup 9} cm{sup -3}) density, which is a consequence of the large momentum transfer per photon at 389 nm and a small two-body loss rate coefficient (2x10{sup -10} cm{sup 3}/s<{beta}<1.0x10{sup -9} cm{sup 3}/s). The two-body loss rate is more than five times smaller than in a MOT on the commonly used 2 {sup 3}S{sub 1}{yields}2 {sup 3}P{sub 2} line at 1083 nm. Furthermore, laser cooling at 389 nm results in temperatures somewhat lower than those achieved using 1083 nm. The 389-nm MOT exhibits small losses due to two-photon ionization, which have been investigated as well.

  18. Alternatives to chemical amplification for 193nm lithography

    NASA Astrophysics Data System (ADS)

    Baylav, Burak; Zhao, Meng; Yin, Ran; Xie, Peng; Scholz, Chris; Smith, Bruce; Smith, Thomas; Zimmerman, Paul

    2010-04-01

    Research has been conducted to develop alternatives to chemically amplified 193 nm photoresist materials that will be able to achieve the requirements associated with sub-32 nm device technology. New as well as older photoresist design concepts for non-chemically amplified 193 nm photoresists that have the potential to enable improvements in line edge roughness while maintaining adequate sensitivity, base solubility, and dry etch resistance for high volume manufacturing are being explored. The particular platforms that have been explored in this work include dissolution inhibitor photoresist systems, chain scissioning polymers, and photoresist systems based on polymers incorporating formyloxyphenyl functional groups. In studies of two-component acidic polymer/dissolution inhibitor systems, it was found that compositions using ortho-nitrobenzyl cholate (NBC) as the dissolution inhibitor and poly norbornene hexafluoro alcohol (PNBHFA) as the base resin are capable of printing 90 nm dense line/space patterns upon exposure to a 193 nm laser. Studies of chain scission enhancement in methylmethacrylate copolymers showed that incorporating small amounts of absorptive a-cleavage monomers significantly enhanced sensitivity with an acceptable increase in absorbance at 193 nm. Specifically, it was found that adding 3 mol% of α-methyl styrene (α-MS) reduced the dose to clear of PMMA-based resist from 1400 mJ/cm2 to 420 mJ/cm2. Preliminary data are also presented on a direct photoreactive design concept based on the photo-Fries reaction of formyloxyphenyl functional groups in acrylic copolymers.

  19. Application of atomic force microscope to 65-nm node photomasks

    NASA Astrophysics Data System (ADS)

    Tanaka, Yoshiyuki; Itou, Yasutoshi; Yoshioka, Nobuyuki; Matsuyama, Katsuhiro; Dawson, Dean J.

    2004-08-01

    The technology node of semiconductor device production is progressing to 65nm generation. For the 65nm photomasks, the target specifications of defect size and repair accuracy are 52nm and 7nm, respectively. Especially, real defects on photomasks are not only simple two-dimensional patterns but also three-dimensional shapes such as phase shift defects and contamination, thus we need to recognize defect shapes accurately. Additionally, AAPSM's Cr patterns overhang, and we have to measure defects on three-dimensional shapes. To evaluate them, we use an AFM metrology system, Dimension X3D (Veeco), having both precise CD measurement repeatability (2nm) and high resolution for defects. In this report, we show the performance of the AFM metrology system. First, we evaluated CD metrology performance, CD repeatbility about four type photomasks: NEGA-BIM, POSI-BIM, KrF-HT and ArF-HT, and all masks met specifications. Next, we evaluated defect pattern shapes and AAPSM and CPL mask patterns. Consequently, we have confirmed that the AFM metrology system has high performance for 65nm photomasks.

  20. Development and validation of different methods manipulating zero order and first order spectra for determination of the partially overlapped mixture benazepril and amlodipine: A comparative study

    NASA Astrophysics Data System (ADS)

    Hemdan, A.

    2016-07-01

    Three simple, selective, and accurate spectrophotometric methods have been developed and then validated for the analysis of Benazepril (BENZ) and Amlodipine (AML) in bulk powder and pharmaceutical dosage form. The first method is the absorption factor (AF) for zero order and amplitude factor (P-F) for first order spectrum, where both BENZ and AML can be measured from their resolved zero order spectra at 238 nm or from their first order spectra at 253 nm. The second method is the constant multiplication coupled with constant subtraction (CM-CS) for zero order and successive derivative subtraction-constant multiplication (SDS-CM) for first order spectrum, where both BENZ and AML can be measured from their resolved zero order spectra at 240 nm and 238 nm, respectively, or from their first order spectra at 214 nm and 253 nm for Benazepril and Amlodipine respectively. The third method is the novel constant multiplication coupled with derivative zero crossing (CM-DZC) which is a stability indicating assay method for determination of Benazepril and Amlodipine in presence of the main degradation product of Benazepril which is Benazeprilate (BENZT). The three methods were validated as per the ICH guidelines and the standard curves were found to be linear in the range of 5-60 μg/mL for Benazepril and 5-30 for Amlodipine, with well accepted mean correlation coefficient for each analyte. The intra-day and inter-day precision and accuracy results were well within the acceptable limits.

  1. Development and validation of different methods manipulating zero order and first order spectra for determination of the partially overlapped mixture benazepril and amlodipine: A comparative study.

    PubMed

    Hemdan, A

    2016-07-01

    Three simple, selective, and accurate spectrophotometric methods have been developed and then validated for the analysis of Benazepril (BENZ) and Amlodipine (AML) in bulk powder and pharmaceutical dosage form. The first method is the absorption factor (AF) for zero order and amplitude factor (P-F) for first order spectrum, where both BENZ and AML can be measured from their resolved zero order spectra at 238nm or from their first order spectra at 253nm. The second method is the constant multiplication coupled with constant subtraction (CM-CS) for zero order and successive derivative subtraction-constant multiplication (SDS-CM) for first order spectrum, where both BENZ and AML can be measured from their resolved zero order spectra at 240nm and 238nm, respectively, or from their first order spectra at 214nm and 253nm for Benazepril and Amlodipine respectively. The third method is the novel constant multiplication coupled with derivative zero crossing (CM-DZC) which is a stability indicating assay method for determination of Benazepril and Amlodipine in presence of the main degradation product of Benazepril which is Benazeprilate (BENZT). The three methods were validated as per the ICH guidelines and the standard curves were found to be linear in the range of 5-60μg/mL for Benazepril and 5-30 for Amlodipine, with well accepted mean correlation coefficient for each analyte. The intra-day and inter-day precision and accuracy results were well within the acceptable limits. PMID:27078209

  2. The effect of laser wavelength on the Raman Spectra of phenanthrene, chrysene, and tetracene: implications for extra-terrestrial detection of polyaromatic hydrocarbons.

    PubMed

    Alajtal, A I; Edwards, H G M; Elbagerma, M A; Scowen, I J

    2010-06-01

    Raman spectroscopy, with visible laser (514 and 633 nm) and near infrared (785 and 1064 nm) excitation, has been used to obtain high quality spectra of phenanthrene, chrysene, and tetracene. Samples with dimensions from a minimum size of 10 microm have been analyzed utilizing a Raman microprobe fitted with a charge-coupled device (CCD) array detector and a FT-Raman instrument. Fluorescence is observed for samples using visible 514, 633 and near infrared 785 nm excitation but most of the samples can be measured with a near infrared 1064 nm Nd:YAG laser.

  3. The effect of laser wavelength on the Raman Spectra of phenanthrene, chrysene, and tetracene: Implications for extra-terrestrial detection of polyaromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Alajtal, A. I.; Edwards, H. G. M.; Elbagerma, M. A.; Scowen, I. J.

    2010-06-01

    Raman spectroscopy, with visible laser (514 and 633 nm) and near infrared (785 and 1064 nm) excitation, has been used to obtain high quality spectra of phenanthrene, chrysene, and tetracene. Samples with dimensions from a minimum size of 10 μm have been analyzed utilizing a Raman microprobe fitted with a charge-coupled device (CCD) array detector and a FT-Raman instrument. Fluorescence is observed for samples using visible 514, 633 and near infrared 785 nm excitation but most of the samples can be measured with a near infrared 1064 nm Nd:YAG laser.

  4. Foliar Reflectance and Fluorescence Responses for Corn and Soybean Plants Under Nitrogen Stress

    NASA Technical Reports Server (NTRS)

    Middleton, E. M.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; McMurtrey, J. E.

    2003-01-01

    We are investigating the use of spectral indices derived from actively induced fluorescence spectra and passive optical spectra. We examined the influence of photosynthetic pigment, carbon (C) and nitrogen (N) content on the spectral fluorescence and passive optical property characteristics of mature, upper leaves from plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of recommended N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight. Steady state laser-induced fluorescence emission spectra (5 nm resolution) were obtained from adaxial and abaxial surfaces resulting from excitation at single wavelengths (280, 380 or 360, and 532 nm). For emission spectra produced by each of these excitation wavelengths, ratios of emission peaks were calculated, including the red far-red chlorophyll fluorescence (ChlF) ratio (F685/F740) and the far-red/green (F740/F525) ratio. High resolution (< 3 nm) optical spectra (350-2500 nm) of reflectance, transmittance, and absorptance were also acquired for both adaxial and abaxial leaf surfaces. Species differences were demonstrated for several optical parameters. A 'red edge' derivative ratio determined from transmittance spectra [as the maximum first deivative, between 650-750 nm, normalized to the value at 744 nm, or Dmax/D744], was strongly associated with the C/N ratio (r(exp 2) = 0.90, P +/- 0.001). This ratio, calculated from reflectance spectra, was inversely related to chlorophyll b content (r(exp 2) = 0.91, P +/- 0.001) as was the ChlF (F685/F740) ratio obtained with 532 nm excitation (r(exp 2) = 0.76, P +/- 0.01). Discrimination of N treatment groups was possible with specific fluorescence band ratios (e.g., F740/F525 obtained with 380 nm excitation). Higher ChlF and blue-green emissions were measured from the abaxial leaf surfaces

  5. Electronic Spectroscopy of Combustion Generated Small PAH's by R2PI from 207 to 320 nm

    NASA Astrophysics Data System (ADS)

    Carpentier, Y.; Pino, T.; Bréchignac, Ph.

    2009-06-01

    The Polycyclic Aromatic Hydrocarbons (PAHs) could be responsible for the so-called UV bump near 217 nm in the interstellar extinction curve. In order to test this conjecture, the electronic spectra of gas phase relevant species have to be investigated. This paper will present the results of such measurements obtained using two-photon resonantly enhanced laser ionization. The newly built experimental set-up called "Nanograins" has been used to generate a non-biased ensemble of PAHs from the combustion of hydrocarbons in a premixed low-pressure flame thanks to a flat burner. The combustion products are extracted from the flame by means of a sampling quartz cone, then mixed with a buffer gas to flow through a nozzle and skimmer assembly before being UV laser ionized further downstream within the acceleration zone of an orthogonal linear time-of-flight mass spectrometer. Wavelength scanning of the UV laser allows the simultaneous recording of many species thanks to the mass resolution. The obtained spectra will be presented and commented upon, with particular attention to the region of the interstellar extinction bump.

  6. Raman spectroscopic differentiation of beef and horse meat using a 671 nm microsystem diode laser

    NASA Astrophysics Data System (ADS)

    Ebrahim, Halah Al; Sowoidnich, Kay; Kronfeldt, Heinz-Detlef

    2013-11-01

    A non-invasive Raman spectroscopic approach for meat species identification and quality detection was successfully demonstrated for the two closely related species beef and horse. Fresh beef and horse muscles were cut and ice-stored at 5 °C, and time-dependent Raman measurements were performed daily up to 12 days postmortem. Applying a 671 nm microsystem diode laser and a laser power of 50 mW, spectra were recorded with integration times of 1-4 s. A pronounced offset of the Raman spectra was observed between horse and beef, with high fluorescence background for horse compared to beef for all days of storage. Principal components analysis was applied for data evaluation revealing a clear distinction between beef and horse meat which can be attributed to differences in the myoglobin content of both species. Furthermore, separations according to aging and spoilage for the two species could be identified simultaneously. Therefore, Raman spectroscopy might be an efficient test method for meat species identification in combination with spoilage detection.

  7. Sulphur abundances in halo giants from the [S I] line at 1082 nm and the [S I] triplet around 1045 nm

    NASA Astrophysics Data System (ADS)

    Jönsson, H.; Ryde, N.; Nissen, P. E.; Collet, R.; Eriksson, K.; Asplund, M.; Gustafsson, B.

    2011-06-01

    Context. It is still debated whether or not the Galactic chemical evolution of sulphur in the halo follows the flat trend with [Fe/H] that is ascribed to the result of explosive nucleosynthesis in type II SNe. It has been suggested that the disagreement between different investigations of sulphur abundances in halo stars might be owing to problems with the diagnostics used, that a new production source of sulphur might be needed in the early Universe, like hypernovae, or that the deposition of supernova ejecta into the interstellar medium is time-delayed. Aims: The aim of this study is to try to clarify this situation by measuring the sulphur abundance in a sample of halo giants using two diagnostics: the S i triplet around 1045 nm and the [S i] line at 1082 nm. The latter of the two is not believed to be sensitive to non-LTE effects. We can thereby minimize the uncertainties in the diagnostic used and estimate the usefulness of the triplet for the sulphur determination in halo K giants. We will also be able to compare our sulphur abundance differences from the two diagnostics with the expected non-LTE effects in the 1045 nm triplet previously calculated by others. Methods: High-resolution near-infrared spectra of ten K giants were recorded using the spectrometer CRIRES mounted at VLT. Two standard settings were used, one covering the S i triplet and one covering the [S i] line. The sulphur abundances were individually determined with equivalent widths and synthetic spectra for the two diagnostics using tailored 1D model atmospheres and relying on non-LTE corrections from the litterature. Effects of convective inhomogeneities in the stellar atmospheres are investigated. Results: The sulphur abundances derived from both the [S i] line and the non-LTE corrected 1045 nm triplet favor a flat trend for the evolution of sulphur. In contrast to some previous studies, we saw no "high" values of [S/Fe] in our sample. Conclusions: We corroborate the flat trend in the [S

  8. [Characteristics of Raman Spectra of Polyethylene Terephthalate].

    PubMed

    Tong, Na; Zhu, Chang-jun; Song, Li-xun; Zhang, Chong-hui; Zhang, Guo-qing; Zhang, Yi-xin

    2016-01-01

    Raman spectrometry was employed to study the characteristics of Raman spectra of polyethylene terephthalate (PET), which were treated with sodium hydroxide, sulfuric acid and copper sulfate, respectively. Raman spectra under different conditions were obtained and the characteristics of the Raman spectra were analyzed. The morphology structures were observed under different conditions using Atomic Force Microscope. The results show that the spectral intensity of PET treated with sodium hydroxide is higher than that untreated between 200-1 750 cm(-1), while the intensity of PET treated with sodium hydroxide is lower than that untreated beyond 1 750 cm(-1) and the fluorescence background of Raman spectra is decreased. The spectral intensity of PET treated with sulfuric acid is remarkably reduced than that untreated, and the intensity of PET treated with copper sulphate is much higher than that untreated. The research results obtained by Atomic Force Microscopy show that the variations of the Raman spectra of PET fibers are closely related to. the chemical bonds and molecular structures of PET fibers. The surface of the PET treated with sodium hydroxide is rougher than that untreated, the surface roughness of the PET treated with sulfuric acid is reduced as compared to that untreated, while the surface roughness of the PET treated with copper sulphate is increased. The results obtained by Raman spectroscopy are consistent with those by Atomic Force Microscopy, indicating that the combination of Raman spectroscopy and Atomic Force Microscopy is expected to be a promising characterization technology for polymer characteristics. PMID:27228752

  9. Cloud supersaturations from CCN spectra Hoppel minima

    NASA Astrophysics Data System (ADS)

    Hudson, James G.; Noble, Stephen; Tabor, Samantha

    2015-04-01

    High-resolution cloud condensation nucleus (CCN) spectral measurements in two aircraft field projects, Marine Stratus/Stratocumulus Experiment (MASE) and Ice in Clouds Experiment-Tropical (ICE-T), often showed bimodality that had previously been observed in submicrometer aerosol size distributions obtained by differential mobility analyzers. However, a great deal of spectral shape variability from very bimodal to very monomodal was observed in close proximity. Cloud supersaturation (S) estimates based on critical S, Sc, at minimal CCN concentrations between two modes (Hoppel minima) were ascertained for 63% of 325 measured spectra. These cloud S were lower than effective S (Seff) determined by comparing ambient CCN spectra with nearby cloud droplet concentrations (Nc). Averages for the polluted MASE stratus were 0.15 and 0.23% and for the cumulus clouds of ICE-T 0.44 and 1.03%. This cloud S disagreement between the two methods might in part be due to the fact that Hoppel minima include the effects of cloud processing, which push CCN spectra toward lower S. Furthermore, there is less cloud processing by the smaller cloud droplets, which might be related to smaller droplets evaporating more readily. Significantly lower concentrations within the more bimodal spectra compared with the monomodal spectra indicated active physical processes: Brownian capture of interstitial CCN and droplet coalescence. Chemical cloud processing also contributed to bimodality, especially in MASE.

  10. Disk-averaged synthetic spectra of Mars.

    PubMed

    Tinetti, Giovanna; Meadows, Victoria S; Crisp, David; Fong, William; Velusamy, Thangasamy; Snively, Heather

    2005-08-01

    The principal goal of the NASA Terrestrial Planet Finder (TPF) and European Space Agency's Darwin mission concepts is to directly detect and characterize extrasolar terrestrial (Earthsized) planets. This first generation of instruments is expected to provide disk-averaged spectra with modest spectral resolution and signal-to-noise. Here we use a spatially and spectrally resolved model of a Mars-like planet to study the detectability of a planet's surface and atmospheric properties from disk-averaged spectra. We explore the detectability as a function of spectral resolution and wavelength range, for both the proposed visible coronograph (TPFC) and mid-infrared interferometer (TPF-I/Darwin) architectures. At the core of our model is a spectrum-resolving (line-by-line) atmospheric/surface radiative transfer model. This model uses observational data as input to generate a database of spatially resolved synthetic spectra for a range of illumination conditions and viewing geometries. The model was validated against spectra recorded by the Mars Global Surveyor-Thermal Emission Spectrometer and the Mariner 9-Infrared Interferometer Spectrometer. Results presented here include disk-averaged synthetic spectra, light curves, and the spectral variability at visible and mid-infrared wavelengths for Mars as a function of viewing angle, illumination, and season. We also considered the differences in the spectral appearance of an increasingly ice-covered Mars, as a function of spectral resolution, signal-to-noise and integration time for both TPF-C and TPFI/ Darwin.

  11. [Characteristics of Raman Spectra of Polyethylene Terephthalate].

    PubMed

    Tong, Na; Zhu, Chang-jun; Song, Li-xun; Zhang, Chong-hui; Zhang, Guo-qing; Zhang, Yi-xin

    2016-01-01

    Raman spectrometry was employed to study the characteristics of Raman spectra of polyethylene terephthalate (PET), which were treated with sodium hydroxide, sulfuric acid and copper sulfate, respectively. Raman spectra under different conditions were obtained and the characteristics of the Raman spectra were analyzed. The morphology structures were observed under different conditions using Atomic Force Microscope. The results show that the spectral intensity of PET treated with sodium hydroxide is higher than that untreated between 200-1 750 cm(-1), while the intensity of PET treated with sodium hydroxide is lower than that untreated beyond 1 750 cm(-1) and the fluorescence background of Raman spectra is decreased. The spectral intensity of PET treated with sulfuric acid is remarkably reduced than that untreated, and the intensity of PET treated with copper sulphate is much higher than that untreated. The research results obtained by Atomic Force Microscopy show that the variations of the Raman spectra of PET fibers are closely related to. the chemical bonds and molecular structures of PET fibers. The surface of the PET treated with sodium hydroxide is rougher than that untreated, the surface roughness of the PET treated with sulfuric acid is reduced as compared to that untreated, while the surface roughness of the PET treated with copper sulphate is increased. The results obtained by Raman spectroscopy are consistent with those by Atomic Force Microscopy, indicating that the combination of Raman spectroscopy and Atomic Force Microscopy is expected to be a promising characterization technology for polymer characteristics.

  12. Climatology of tropospheric vertical velocity spectra

    NASA Technical Reports Server (NTRS)

    Ecklund, W. L.; Gage, K. S.; Balsley, B. B.; Carter, D. A.

    1986-01-01

    Vertical velocity power spectra obtained from Poker Flat, Alaska; Platteville, Colorado; Rhone Delta, France; and Ponape, East Caroline Islands using 50-MHz clear-air radars with vertical beams are given. The spectra were obtained by analyzing the quietest periods from the one-minute-resolution time series for each site. The lengths of available vertical records ranged from as long as 6 months at Poker Flat to about 1 month at Platteville. The quiet-time vertical velocity spectra are shown. Spectral period ranging from 2 minutes to 4 hours is shown on the abscissa and power spectral density is given on the ordinate. The Brunt-Vaisala (B-V) periods (determined from nearby sounding balloons) are indicated. All spectra (except the one from Platteville) exhibit a peak at periods slightly longer than the B-V period, are flat at longer periods, and fall rapidly at periods less than the B-V period. This behavior is expected for a spectrum of internal waves and is very similar to what is observed in the ocean (Eriksen, 1978). The spectral amplitudes vary by only a factor of 2 or 3 about the mean, and show that under quiet conditions vertical velocity spectra from the troposphere are very similar at widely different locations.

  13. H. N. Russell and Atomic Spectra

    NASA Astrophysics Data System (ADS)

    Devorkin, David

    2001-04-01

    “I would rather analyze spectra than do cross-word puzzles or do almost anything else” Henry Norris Russell wrote to William F. Meggers in 1927. Meggers, chief of the spectroscopy division at the NBS, had been surprised that an astrophysicist could be so keen about the analysis of complex spectra. But Russell was a new type of astrophysicist, one who made physics the core of his research. Spectra, for Russell, held the "master key" to knowledge about the universe, and of the atom. He was first attracted by the challenge of detecting and explaining anomalies, which he hoped would lead to new knowledge about the structure of matter. Then, influenced by physicists such as Meggers, he devoted himself to filling in the picture of the structure of atoms from their characteristic spectra as completely as possible. In this talk I will review how Russell worked with Meggers and became the nucleus of an ever-widening circle of spectroscopists devoted to the analysis of complex spectra.

  14. Cleaning HI Spectra Contaminated by GPS RFI

    NASA Astrophysics Data System (ADS)

    Sylvia, Kamin; Hallenbeck, Gregory L.; Undergraduate ALFALFA Team

    2016-01-01

    The NUDET systems aboard GPS satellites utilize radio waves to communicate information regarding surface nuclear events. The system tests appear in spectra as RFI (radio frequency interference) at 1381MHz, which contaminates observations of extragalactic HI (atomic hydrogen) signals at 50-150 Mpc. Test durations last roughly 20-120 seconds and can occur upwards of 30 times during a single night of observing. The disruption essentially renders the corresponding HI spectra useless.We present a method that automatically removes RFI in HI spectra caused by these tests. By capitalizing on the GPS system's short test durations and predictable frequency appearance we are able to devise a method of identifying times containing compromised data records. By reevaluating the remaining data, we are able to recover clean spectra while sacrificing little in terms of sensitivity to extragalactic signals. This method has been tested on 500+ spectra taken by the Undergraduate ALFALFA Team (UAT), in which it successfully identified and removed all sources of GPS RFI. It will also be used to eliminate RFI in the upcoming Arecibo Pisces-Perseus Supercluster Survey (APPSS).This work has been supported by NSF grant AST-1211005.

  15. Background noise spectra of global seismic stations

    SciTech Connect

    Wada, M.M.; Claassen, J.P.

    1996-08-01

    Over an extended period of time station noise spectra were collected from various sources for use in estimating the detection and location performance of global networks of seismic stations. As the database of noise spectra enlarged and duplicate entries became available, an effort was mounted to more carefully select station noise spectra while discarding others. This report discusses the methodology and criteria by which the noise spectra were selected. It also identifies and illustrates the station noise spectra which survived the selection process and which currently contribute to the modeling efforts. The resulting catalog of noise statistics not only benefits those who model network performance but also those who wish to select stations on the basis of their noise level as may occur in designing networks or in selecting seismological data for analysis on the basis of station noise level. In view of the various ways by which station noise were estimated by the different contributors, it is advisable that future efforts which predict network performance have available station noise data and spectral estimation methods which are compatible with the statistics underlying seismic noise. This appropriately requires (1) averaging noise over seasonal and/or diurnal cycles, (2) averaging noise over time intervals comparable to those employed by actual detectors, and (3) using logarithmic measures of the noise.

  16. Spectra from nuclear-excited plasmas

    NASA Technical Reports Server (NTRS)

    De Young, R. J.; Weaver, W. R.

    1980-01-01

    The paper discusses the spectra taken from He-3(n,p)H-3 nuclear-induced plasmas under high thermal neutron flux, lasing conditions. Also, initial spectra are presented for U-235F6 generated plasmas. From an evaluation of these spectra, important atomic and molecular processes that occur in the plasma can be inferred. The spectra presented are the first to be generated by He-3 and U-235F6 nuclear reactions under high neutron flux, lasing conditions. The U-235(n,ff)FF reaction, which liberates 165 MeV of fission-fragment kinetic energy, creates plasmas that are of great interest, since at sufficiently high densities of U-235F6 the gas becomes self-critical; thus, there is no need for an external driving reactor (source of neutrons). The spectra from mixtures of He-3 and Ar, Xe, Kr, Ne, Cl2, F2 and N2 indicate little difference between high-pressure nuclear-induced plasmas and high-pressure electrically pulsed afterglow plasmas for noble-gas systems

  17. Disk-averaged synthetic spectra of Mars.

    PubMed

    Tinetti, Giovanna; Meadows, Victoria S; Crisp, David; Fong, William; Velusamy, Thangasamy; Snively, Heather

    2005-08-01

    The principal goal of the NASA Terrestrial Planet Finder (TPF) and European Space Agency's Darwin mission concepts is to directly detect and characterize extrasolar terrestrial (Earthsized) planets. This first generation of instruments is expected to provide disk-averaged spectra with modest spectral resolution and signal-to-noise. Here we use a spatially and spectrally resolved model of a Mars-like planet to study the detectability of a planet's surface and atmospheric properties from disk-averaged spectra. We explore the detectability as a function of spectral resolution and wavelength range, for both the proposed visible coronograph (TPFC) and mid-infrared interferometer (TPF-I/Darwin) architectures. At the core of our model is a spectrum-resolving (line-by-line) atmospheric/surface radiative transfer model. This model uses observational data as input to generate a database of spatially resolved synthetic spectra for a range of illumination conditions and viewing geometries. The model was validated against spectra recorded by the Mars Global Surveyor-Thermal Emission Spectrometer and the Mariner 9-Infrared Interferometer Spectrometer. Results presented here include disk-averaged synthetic spectra, light curves, and the spectral variability at visible and mid-infrared wavelengths for Mars as a function of viewing angle, illumination, and season. We also considered the differences in the spectral appearance of an increasingly ice-covered Mars, as a function of spectral resolution, signal-to-noise and integration time for both TPF-C and TPFI/ Darwin. PMID:16078866

  18. Chemical characterization of individual, airborne sub-10-nm particles and molecules.

    PubMed

    Wang, Shenyi; Zordan, Christopher A; Johnston, Murray V

    2006-03-15

    A nanoaerosol mass spectrometer (NAMS) is described for real-time characterization of individual airborne nanoparticles. The NAMS includes an aerodynamic inlet, quadrupole ion guide, quadrupole ion trap, and time-of-flight mass analyzer. Charged particles in the aerosol are drawn through the aerodynamic inlet, focused through the ion guide, and captured in the ion trap. Trapped particles are irradiated with a high-energy laser pulse to reach the "complete ionization limit" where each particle is thought to be completely disintegrated into atomic ions. In this limit, the relative signal intensities of the atomic ions give the atomic composition. The method is first demonstrated with sucrose particles produced with an electrospray generator. Under the conditions used, the particle detection efficiency (fraction of charged particles entering the inlet that are subsequently analyzed) reaches a maximum of 10(-4) at 9.5 nm in diameter and the size distribution of trapped particles has a geometric standard deviation of 1.1 based on a log-normal distribution. A method to deconvolute overlapping multiply charged ions (e.g. C3+ and O4+) is presented. When applied to sucrose spectra, the measured C/O atomic ratio is 1.1, which matches the expected ratio from the molecular formula. The spectra of singly charged bovine serum albumin (BSA) molecules are also presented, and the measured and expected C/N/O atomic ratios are within 15% of the each other. Also observed in the BSA spectra are signals from 13C and 32S which arise from 40 and approximately 34 atoms per molecule (particle), respectively. Potential applications of NAMS to atmospheric chemistry and biotechnology are briefly discussed. PMID:16536407

  19. Highly efficient continuous-wave 912 nm Nd:GdVO4 laser emission under direct 880 nm pumping

    NASA Astrophysics Data System (ADS)

    Lü, Y. F.; Zhang, X. H.; Xia, J.; Zhang, A. F.; Yin, X. D.; Bao, L.

    2009-11-01

    The quasi-three-level 912 nm continuous-wave laser emission under direct diode laser pumping at 880 nm into emitting level 4F3/2 of Nd:GdVO4 have been demonstrated. An end-pumped Nd:GdVO4 crystal yielded 8.1 W of output power for 13.9 W of absorbed pump power. The slope efficiency with respect to the absorbed pump power was 0.679. To the best of our knowledge this is the first demonstration of such a laser system. Comparative results obtained for the pump with diode laser at 808 nm, into the highly-absorbing 4F5/2 level, are given in order to prove the advantages of the 880 nm wavelength pumping.

  20. 750 nm 1.5 W frequency-doubled semiconductor disk laser with a 44 nm tuning range.

    PubMed

    Saarinen, Esa J; Lyytikäinen, Jari; Ranta, Sanna; Rantamäki, Antti; Sirbu, Alexei; Iakovlev, Vladimir; Kapon, Eli; Okhotnikov, Oleg G

    2015-10-01

    We demonstrate 1.5 W of output power at the wavelength of 750 nm by intracavity frequency doubling a wafer-fused semiconductor disk laser diode-pumped at 980 nm. An optical-to-optical efficiency of 8.3% was achieved using a bismuth borate crystal. The wavelength of the doubled emission could be tuned from 720 to 764 nm with an intracavity birefringent plate. The beam quality parameter M2 of the laser output was measured to be below 1.5 at all pump powers. The laser is a promising tool for biomedical applications that can take advantage of the large penetration depth of light in tissue in the 700-800 nm spectral range.