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Sample records for absorption spectrum suggesting

  1. Ultraviolet absorption spectrum of HOCl

    NASA Technical Reports Server (NTRS)

    Burkholder, James B.

    1993-01-01

    The room temperature UV absorption spectrum of HOCl was measured over the wavelength range 200 to 380 nm with a diode array spectrometer. The absorption spectrum was identified from UV absorption spectra recorded following UV photolysis of equilibrium mixtures of Cl2O/H2O/HOCl. The HOCl spectrum is continuous with a maximum at 242 nm and a secondary peak at 304 nm. The measured absorption cross section at 242 nm was (2.1 +/- 0.3) x 10 exp -19/sq cm (2 sigma error limits). These results are in excellent agreement with the work of Knauth et al. (1979) but in poor agreement with the more recent measurements of Mishalanie et al. (1986) and Permien et al. (1988). An HOCl nu2 infrared band intensity of 230 +/- 35/sq cm atm was determined based on this UV absorption cross section. The present results are compared with these previous measurements and the discrepancies are discussed.

  2. Visible absorption spectrum of liquid ethylene

    PubMed Central

    Nelson, Edward T.; Patel, C. Kumar N.

    1981-01-01

    The visible absorption spectrum of liquid ethylene at ≈ 108 K from 5500 Å to 7200 Å was measured by using a pulsed tunable dye laser, immersed-transducer, gated-detection opto-acoustic spectroscopy technique. The absorption features show the strongest band with an absorption coefficient of ≈2 × 10-2 cm-1 and the weakest band with an absorption coefficient of ≈1 × 10-4 cm-1. Proposed assignments of the observed absorption peaks involve combinations of overtones of local and normal modes of vibration of ethylene. PMID:16592978

  3. Quantum Entanglement Molecular Absorption Spectrum Simulator

    NASA Technical Reports Server (NTRS)

    Nguyen, Quang-Viet; Kojima, Jun

    2006-01-01

    Quantum Entanglement Molecular Absorption Spectrum Simulator (QE-MASS) is a computer program for simulating two photon molecular-absorption spectroscopy using quantum-entangled photons. More specifically, QE-MASS simulates the molecular absorption of two quantum-entangled photons generated by the spontaneous parametric down-conversion (SPDC) of a fixed-frequency photon from a laser. The two-photon absorption process is modeled via a combination of rovibrational and electronic single-photon transitions, using a wave-function formalism. A two-photon absorption cross section as a function of the entanglement delay time between the two photons is computed, then subjected to a fast Fourier transform to produce an energy spectrum. The program then detects peaks in the Fourier spectrum and displays the energy levels of very short-lived intermediate quantum states (or virtual states) of the molecule. Such virtual states were only previously accessible using ultra-fast (femtosecond) laser systems. However, with the use of a single-frequency continuous wave laser to produce SPDC photons, and QEMASS program, these short-lived molecular states can now be studied using much simpler laser systems. QE-MASS can also show the dependence of the Fourier spectrum on the tuning range of the entanglement time of any externally introduced optical-path delay time. QE-MASS can be extended to any molecule for which an appropriate spectroscopic database is available. It is a means of performing an a priori parametric analysis of entangled photon spectroscopy for development and implementation of emerging quantum-spectroscopic sensing techniques. QE-MASS is currently implemented using the Mathcad software package.

  4. Ultraviolet absorption spectrum of gaseous HOCl

    SciTech Connect

    Mishalanie, E.A; Rutkowski, C.J.; Hutte, R.S.; Birks, J.W.

    1986-10-23

    The UV absorption spectrum of gaseous HOCl was investigated in the wavelength region 240 to 390 nm by using a dynamic HOCl source. Substantial quantities of HOCl were produced compared to two species (Cl/sub 2/O, ClO/sub 2/) that are spectral interferences in the wavelength region of interest. Thirteen experimental absorption spectra were analyzed by the statistical method of factor analysis. This analysis revealed that two major components were contributing to the total absorbance in each spectrum and that these two components accounted for 99.97% of all variance in the data. Mass spectra were simultaneously recorded with the absorption spectra by a quadrupole mass spectrometer that was calibrated for HOCl, Cl/sub 2/, Cl/sub 2/O, ClO/sub 2/, and other species. The two components in the absorption spectra were identified as Cl/sub 2/ and HOCl containing trace levels of ClO/sub 2/. The isolated Cl/sub 2/ and HOCl/ClO/sub 2/ spectral curves were obtained from a spectral-isolation factor analysis and quantified by using the Cl/sub 2/ spectrum as an internal standard. Atmospheric photolysis constants averaged over 24 h were calculated as a function of altitude from these cross sections and those currently recommended for atmospheric modeling. The calculated j values from the cross sections generated in this work predict a shorter photolysis lifetime for HOCl above 28 km. This results in a 6 to 19% decrease in the predicted HOCl diurnal average concentration in the altitude region 28 to 34 km, respectively, compared to the concentrations predicted by the currently recommended cross sections.

  5. Absorption spectrum of DNA for wavelengths greater than 300 nm

    SciTech Connect

    Sutherland, J.C.; Griffin, K.P.

    1981-06-01

    Although DNA absorption at wavelengths greater than 300 nm is much weaker than that at shorter wavelengths, this absorption seems to be responsible for much of the biological damage caused by solar radiation of wavelengths less than 320 nm. Accurate measurement of the absorption spectrum of DNA above 300 nm is complicated by turbidity characteristic of concentrated solutions of DNA. We have measured the absorption spectra of DNA from calf thymus, Clostridium perfringens, Escherichia coli, Micrococcus luteus, salmon testis, and human placenta using procedures which separate optical density due to true absorption from that due to turbidity. Above 300 nm, the relative absorption of DNA increases as a function of guanine-cytosine content, presumably because the absorption of guanine is much greater than the absorption of adenine at these wavelengths. This result suggests that the photophysical processes which follow absorption of a long-wavelength photon may, on the average, differ from those induced by shorter-wavelength photons. It may also explain the lower quantum yield for the killing of cells by wavelengths above 300 nm compared to that by shorter wavelengths.

  6. The Absorption Spectrum of Iodine Vapour

    ERIC Educational Resources Information Center

    Tetlow, K. S.

    1972-01-01

    A laboratory experiment is described which presents some molecular parameters of iodine molecule by studying iodine spectrum. Points out this experiment can be conducted by sixth form students in high school laboratories. (PS)

  7. Vertical transition energies vs. absorption maxima: illustration with the UV absorption spectrum of ethylene.

    PubMed

    Lasorne, Benjamin; Jornet-Somoza, Joaquim; Meyer, Hans-Dieter; Lauvergnat, David; Robb, Michael A; Gatti, Fabien

    2014-02-01

    We revisit the validity of making a direct comparison between measured absorption maxima and computed vertical transition energies within 0.1 eV to calibrate an excited-state level of theory. This is illustrated on the UV absorption spectrum of ethylene for which the usual experimental values of 7.66 eV (V←N) and 7.11 eV (R(3s)←N) cannot be compared directly to the results of electronic structure calculations for two very different reasons. After validation of our level of theory against experimental data, a new experimental reference of 7.28 eV is suggested for benchmarking the Rydberg state, and the often-cited average transition energy (7.80 eV) is confirmed as a safer estimate for the valence state. PMID:23711543

  8. Extreme-ultraviolet absorption spectrum of Ga+

    NASA Astrophysics Data System (ADS)

    Dunne, P.; O'sullivan, G.; Ivanov, V. K.

    1993-12-01

    Time-resolved photoabsorption spectra of gallium plasmas have been photographed in the 50-450-Å region using the dual-laser-produced-plasma technique. The absorbing plasmas were produced by focusing the output of a Q-switched ruby laser onto slab targets while the background continuum was produced by focusing the output of a Nd:YAG oscillator-amplifier system (where Nd:YAG denotes neodymium-doped yttrium-aluminum-garnet) onto a samarium or hafnium target. At 130-ns delay between the two pulses the spectrum recorded was due almost exclusively to Ga+. We have observed transitions due to both 3d and 3p excitation. In the former case we identified 3d104s2-3d94s2nf and 3d94s2np series converging on the 2D3/2 and 2D5/2 limits of Ga2+. In the 3p case no strong transitions were observed because of line broadening by super-Coster-Kronig decay of the 3p hole. The identifications were made by comparison with the predictions of Hartree-Fock and Dirac-Fock atomic-structure codes. Many-body calculations were also performed which proved invaluable in estimating the effects of different decay processes. The theoretical predictions are compared with the experimental data.

  9. On the Absorption Spectrum of Noble Gases at the Arc Spectrum Limit

    PubMed Central

    Fano, Ugo; Pupillo, Guido; Zannoni, Alberto; Clark, Charles W.

    2005-01-01

    Rydberg spectral lines of an atom are sometimes superimposed on the continuous spectrum of a different configuration. Effects of interaction among different configurations in one of these cases are theoretically investigated, and a formula is obtained that describes the behavior of absorption spectrum intensity. This offers qualitative justification of some experimental results obtained by BEUTLER in studies of absorption arc spectra of noble gases and Ib spectra of some metal vapors. PMID:27308180

  10. Optical absorption spectrum of Cu 2+ in calcium tartrate tetrahydrate

    NASA Astrophysics Data System (ADS)

    Swamy, Y. K. R.; Reddy, P. P.; Reddy, Y. P.

    1980-02-01

    Copper doped single crystals of calcium tartrate tetrahydrate are grown from silica gel. The optical absorption spectrum is investigated with polarised and unpolarised beams of incident light. The spectrum is attributed to the Cu 2+ ion in C 4V symmetry associated with spin-orbit coupling. The following crystal field parameters are evaluated: Dq = 1000 cm -1; λ = -830 cm -1; Ds = 1540 cm -1; Dt = 470 cm -1.

  11. Ultraviolet absorption spectrum of chlorine nitrite, ClONO

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    The near-ultraviolet absorption spectrum of chlorine nitrite (ClONO) has been quantitatively investigated over the wavelength range 230-400 nm at 231 K. An absorption maximum was observed at 290 nm with a cross section of 1.5 by 10 to the -18th power sq cm. The calculated lifetime against photodissociation for ClONO in the atmosphere is 2 to 3 minutes. The large photolysis rate indicates that ClONO does not play a significant role in the stratosphere as a temporary holding tank for chlorine.

  12. The Absorption Spectrum of the η Car Ejecta

    NASA Astrophysics Data System (ADS)

    Nielsen, K. E.; Viera, G.; Gull, T. R.

    2005-09-01

    The ultraviolet spectrum of η Car and the very nearby ejecta is dominated by complex wind profiles of the extended atmosphere. Increasingly from the STIS NUV to FUV, absorption features from the ejecta and the interstellar medium are superimposed. The absorption from the foreground ejecta display a velocity dispersion between -650 > v > -100 km s-1, with two easily separated components at -146 and -513 km s-1. These two velocities components have earlier been determined to be formed at very different distances from the central source (Gull et al. 2004), and seem to be linked to Little Homunculus and the Homunculus, respectively.The -146 and -513 km s-1 components show different ionization structures. While the -146 km s-1 component shows a spectrum from almost exclusively singly ionized iron group elements, the fast -513 km s-1 has a lower excitation temperature and consequently shows lines from both neutral and singly ionized species. H2 has a huge impact on the spectrum between 1200 to 1650 Å{} and can for some regions completely describe the ejecta spectrum. The ejecta vary in absorption throughout the spectroscopic period. The -146 km s-1 component strengthens when the minimum approaches. The fast component is not significantly affected across the minimum, however, the molecular lines show a dramatic decrease in intensity likely caused by the drop of FUV radiation reaching the -513 km s-1 ejecta. In this spectral range interstellar features such as S II, C II, C IV, Si II and Si IV have a significant impact on the spectrum. We used an earlier study by Walborn et al. (2002) to estimate the ISM's influence on the η Car spectrum. Many of the interstellar lines show a large velocity dispersion (-388 to +127 km s-1). Within 0.1 arcsec of the central source, STIS resolves spatial features at the 0.25 arcsec scale. A number of strong emission lines are observable in the spectrum and associable with the Weigelt blobs B and C. During the minimum when the FUV and X

  13. The UV/Vis absorption spectrum of matrix-isolated dichlorine peroxide, ClOOCl.

    PubMed

    von Hobe, Marc; Stroh, Fred; Beckers, Helmut; Benter, Thorsten; Willner, Helge

    2009-03-14

    UV/Vis absorption spectra of ClOOCl isolated in neon matrices were measured in the wavelength range 220-400 nm. The purity of the trapped samples was checked by infrared and UV/Vis matrix spectroscopy as well as low-temperature Raman spectroscopy. At wavelengths below 290 nm, the results agree with the UV spectrum recently published by Pope et al. [J. Phys. Chem. A, 2007, 111, 4322-4332]. However, the observed absorption in the long wavelength tail of the spectrum-relevant for polar stratospheric ozone loss-is substantially higher than reported by Pope et al. Our results suggest the existence of a ClOOCl electronic state manifold leading to an absorption band similar to those of the near UV spectrum of Cl(2). The differences to previous studies can be accounted for quantitatively by contributions to the reported absorption spectra caused by impurities. The observed band in the long wavelength tail is supported by several high-level ab initio calculations. However, questions arise concerning absolute values of the ClOOCl cross sections, an issue that needs to be revisited in future studies. With calculated photolysis rates based on our spectrum scaled to previous cross sections at the peak absorption, the known polar catalytic ozone-destruction cycles to a large extent account for the observed ozone depletion in the spring polar stratosphere. PMID:19240934

  14. Photoionization and absorption spectrum of formaldehyde in the vacuum ultraviolet.

    NASA Technical Reports Server (NTRS)

    Mentall, J. E.; Gentieu, E. P.; Krauss, M.; Neumann, D.

    1971-01-01

    The measurements have been conducted in the spectral range from 600 to 2000 A. Integrated oscillator strengths were determined for a number of strong Rydberg transitions above 1200 A. From the photoionization curve the first adiabatic ionization potential was found to be 10.87 plus or minus 0.01 eV. As an aid in interpreting the absorption spectrum, theoretical calculations were made using a single-configuration self-consistent field procedure for the Rydberg states and a model which included mixing between the Rydberg and valence states.

  15. Excitonic Effects and Optical Absorption Spectrum of Doped Graphene

    NASA Astrophysics Data System (ADS)

    Jornada, Felipe; Deslippe, Jack; Louie, Steven

    2012-02-01

    First-principles calculations based on the GW-Bethe-Salpeter Equation (GW-BSE) approach and subsequent experiments have shown large excitonic effects in the optical absorbance of graphene. Here we employ the GW-BSE formalism to probe the effects of charge carrier doping and of having an external electric field on the absorption spectrum of graphene. We show that the absorbance peak due to the resonant exciton exhibits systematic changes in both its position and profile when graphene is gate doped by carriers, in excellent agreement to very recent measurementsootnotetextTony F. Heinz, private communications.. We analyze the various contributions to these changes in the absorption spectrum, such as the effects of screening by carriers to the quasiparticle energies and electron-hole interactions. This work was supported by National Science Foundation Grant No. DMR10-1006184, the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, and the U.S. DOD - Office of Naval Research under RTC Grant No. N00014-09-1-1066. Computer time was provided by NERSC.

  16. Temperature dependence of the NO3 absorption spectrum

    NASA Technical Reports Server (NTRS)

    Sander, Stanley P.

    1986-01-01

    The absorption spectrum of the gas-phase NO3 radical has been studied between 220 and 700 nm by using both flash photolysis and discharge flow reactors for the production of NO3. In the flash photolysis method, cross sections at the peak of the (0,0) band at 661.9 nm were measured relative to the cross section of ClONO2 at several different wavelengths. From the best current measurements of the ClONO2 spectrum, the NO3 cross section at 661.9 nm was determined to be (2.28 + or 0.34) x 10 to the -17th sq cm/molecule at 298 K. Measurements at 230 K indicated that the cross section increases by a factor of 1.18 at the peak of the (0,0) band. The discharge flow method was used both to obtain absolute cross sections at 661.9 nm and to obtain relative absorption spectra between 300 and 700 nm at 298 and 230 K. A value of (1.83 + or - 0.27) x 10 to the -17th sq cm/molecule was obtained for sigma NO3 at 661.9 nm at 298 K. Upper limits to the NO3 cross sections were also measured between 220 and 260 nm with the discharge flow method.

  17. ULTRAVIOLET ABSORPTION SPECTRUM OF NITROUS OXIDE AS FUNCTION OF TEMPERATURE AND ISOTOPIC SUBSTITUTION

    SciTech Connect

    Selwyn, G.S.; Johnston, H.S.

    1980-07-01

    The ultraviolet absorption spectra of nitrous oxide and its {sup 15}N isotopes over the wavelength range 197 to 172 nm and between 150 and 500 K show a weak continuous absorption and a pattern of diffuse banding that became pronounced at higher temperatures. The temperature dependence of the absorption spectrum results from the activation of the n{sub 2}{double_prime} bending mode. Deconvolution of the data shows that absorption by molecules in the (010) vibrational mode results in a spectrum of vibrational bands superimposed on a continuum. A weaker and nearly continuous spectrum results from the ultraviolet absorption by molecules in the (000) vibrational mode. Analysis of the structuring indicates n{sub 2}{double_prime} = (490 {+-} 10) cm{sup -1}. No rotational structure can be observed. Measurement of the n{sub 2}{double_prime} isotope shift is used to identify the quantum number of the upper state vibrational levels. Normal coordinate analysis of the excited state is used to determine a self-consistent set of molecular parameters: bond angle (115{sup o}), the values of n{sub 1}{prime} and n{sub 3}{prime} (1372 and 1761 cm{sup -1}, respectively), and the force constants of the upper state. It is suggested that the transitions observed are {sup 1}S{sup -}({sup 1}A{sup -}) {l_arrow} X- {sup 1}{sup +} and {sup 1}D {l_arrow} {tilde X} {sup 1}S{sup +}.

  18. The root economics spectrum: divergence of absorptive root strategies with root diameter

    NASA Astrophysics Data System (ADS)

    Kong, D.; Wang, J.; Kardol, P.; Wu, H.; Zeng, H.; Deng, X.; Deng, Y.

    2015-08-01

    Plant roots usually vary along a dominant ecological axis, the root economics spectrum (RES), depicting a tradeoff between resource acquisition and conservation. For absorptive roots, which are mainly responsible for resource acquisition, we hypothesized that root strategies as predicted from the RES shift with increasing root diameter. To test this hypothesis, we used seven contrasting plant species for which we separated absorptive roots into two categories: thin roots (< 247 μm diameter) and thick roots. For each category, we analyzed a~range of root traits closely related to resource acquisition and conservation, including root tissue density, carbon (C) and nitrogen (N) fractions as well as root anatomical traits. The results showed that trait relationships for thin absorptive roots followed the expectations from the RES while no clear trait relationships were found in support of the RES for thick absorptive roots. Our results suggest divergence of absorptive root strategies in relation to root diameter, which runs against a single economics spectrum for absorptive roots.

  19. The energy spectrum and the optical absorption spectrum of C{sub 60} fullerene within the Hubbard model

    SciTech Connect

    Silant’ev, A. V.

    2015-10-15

    Anticommutator Green’s functions and the energy spectrum of C{sub 60} fullerene are calculated in the approximation of static fluctuations within the Hubbard model. On the basis of this spectrum, an interpretation is proposed for the experimentally observed optical absorption bands of C{sub 60} fullerene. The parameters of C{sub 60} fullerene that characterize it within the Hubbard model are calculated by the optical absorption spectrum.

  20. [The measurement and analysis of visible-absorption spectrum and fluorescence spectrum of lycopene].

    PubMed

    Yang, Xiao-zhan; Li, Ping; Dai, Song-hui; Wu, Da-cheng; Li, Rui-xia; Yang, Jian-hui; Xiao, Hai-bo

    2005-11-01

    Using ICCD spectral detection system, the absorbency of lycopene-carbon bisulfide solution with different concentration was measured, and the result shows that in a specified range the absorption rule of lycopene solution agrees with Lambert-Beer Law. Absorption spectral wavelength shifts were measured respectively when lycopene was dissolved in acetone, normal hexane, petroleum ether, benzene, ethyl acetate, and carbon bisulfide, and comparing to acetone, different red-shift appeared when lycopene was dissolved in benzene, ethyl acetate, and carbon bisulfide when water was added in lycopene-acetone solution, t he absorbency of lycopene dropped, the fine structure of absorption spectrum became indistinct, and a new absorption peak appeared in UV. The reason for these phenomena is that the solvent molecule had different effect on lycopene molecule when lycopene was dissolved in different solvent. Using fluorecence spectrophotometer, fluorescence spectra of lycopene in different concentrations were collected, and the results show that the fluorescence spectra of lycopene were mainly in 500-680 nm. When concentration was lower than 50 microg x mL(-1), the fluorescence intensity linearly increased with increasing concentration, and when concentration was higher than 60 microg x mL(-1), the fluorescence intensity dropped because of the interaction between lycopene molecules. PMID:16499057

  1. Collision-induced absorption in the far infrared spectrum of Titan

    NASA Technical Reports Server (NTRS)

    Hunt, J. L.; Poll, J. D.; Goorvitch, D.; Tipping, R. H.

    1983-01-01

    The effects of collision-induced absorption on the far infrared spectrum of Titan have been investigated. After a review of the procedure for the theoretical calculation of the N2 translation-rotational spectrum, new results for the temperature range o 70 to 120 K are reported. These are used as input data for a simple atmospheric model in order to compute the far infrared radiance, brightness temperature, and specral limb function. This source of opacity alone is not capable of explaining the Voyager results. When the collision-induced methane is included, the results are in closer agreement in the range between 200 and 300/cm, suggesting that a more complete treatment of collision-induced absorption including particularly CH4-N2, N2-H2, and H2-H2 results, may provide sufficient opacity to reduce or obviate the need for opacities due to clouds or aerosols in order to explain the observed spectra.

  2. Temperature dependence of the far-infrared absorption spectrum of gaseous methane.

    NASA Astrophysics Data System (ADS)

    Codastefano, P.; Dore, P.; Nencini, L.

    The rototranslational absorption spectrum of gaseous methane has been measured at seven different temperatures from 296 to 140 K. The authors have analyzed both the spectral moments and the experimental absorption shapes, assuming that only octupolar and hexadecapolar induction mechanisms contribute to the absorption. This assumption allows to parameterize the temperature dependence of both the intensity and the shape of the absorption band. The results obtained indicate that other contributions to absorption are not negligible.

  3. Brief Report: Suggestibility, Compliance and Psychological Traits in High-Functioning Adults with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Maras, Katie L.; Bowler, Dermot M.

    2012-01-01

    Individuals with autism spectrum disorder (ASD) may be over-represented within the criminal justice system; it is therefore important to understand how they fare under police questioning. The present study examined interrogative suggestibility and compliance in individuals with ASD, and whether this is associated with certain psychological traits.…

  4. Discovery of a second narrow absorption feature in the near-infrared spectrum of Io

    NASA Technical Reports Server (NTRS)

    Lester, D. F.; Trafton, L. M.; Ramseyer, T. F.; Gaffney, N. I.

    1992-01-01

    A high resolution survey of the near-IR reflectance spectrum of Io has shown a sharp absorption feature centered at 5045 +/- 1/cm; this feature is not present in laboratory spectra of dilute CO2 in a matrix. Since the spectrum of cold H2S ice crystals exhibits structure near this wavelength, it is suggested that either (1) the difference in width between this feature and that of the much broader Ionian H2S ice may be due to the presence of different phases of ice at different temperatures, so that these are emphasized in the different spectral regions, or (2) H2S is trapped in an SO2 matrix.

  5. [Gas Concentration Measurement Based on the Integral Value of Absorptance Spectrum].

    PubMed

    Liu, Hui-jun; Tao, Shao-hua; Yang, Bing-chu; Deng, Hong-gui

    2015-12-01

    The absorptance spectrum of a gas is the basis for the qualitative and quantitative analysis of the gas by the law of the Lambert-Beer. The integral value of the absorptance spectrum is an important parameter to describe the characteristics of the gas absorption. Based on the measured absorptance spectrum of a gas, we collected the required data from the database of HIT-RAN, and chose one of the spectral lines and calculated the integral value of the absorptance spectrum in the frequency domain, and then substituted the integral value into Lambert-Beer's law to obtain the concentration of the detected gas. By calculating the integral value of the absorptance spectrum we can avoid the more complicated calculation of the spectral line function and a series of standard gases for calibration, so the gas concentration measurement will be simpler and faster. We studied the changing trends of the integral values of the absorptance spectrums versus temperature. Since temperature variation would cause the corresponding variation in pressure, we studied the changing trends of the integral values of the absorptance spectrums versus both the pressure not changed with temperature and changed with the temperature variation. Based on the two cases, we found that the integral values of the absorptance spectrums both would firstly increase, then decrease, and finally stabilize with temperature increasing, but the ranges of specific changing trend were different in the two cases. In the experiments, we found that the relative errors of the integrated values of the absorptance spectrum were much higher than 1% and still increased with temperature when we only considered the change of temperature and completely ignored the pressure affected by the temperature variation, and the relative errors of the integrated values of the absorptance spectrum were almost constant at about only 1% when we considered that the pressure were affected by the temperature variation. As the integral value

  6. INCIDENCE OF Mg II ABSORPTION SYSTEMS TOWARD FLAT-SPECTRUM RADIO QUASARS

    SciTech Connect

    Chand, Hum; Gopal-Krishna E-mail: krishna@ncra.tifr.res.in

    2012-07-20

    The conventional wisdom that the rate of incidence of Mg II absorption systems, dN/dz (excluding 'associated systems' having a velocity {beta}c relative to the active galactic nucleus (AGN) of less than {approx}5000 km s{sup -1}), is totally independent of the background AGNs has been challenged by a recent finding that dN/dz for strong Mg II absorption systems toward distant blazars is 2.2 {+-} {sup 0.8}{sub 0.6} times the value known for normal optically selected quasars (QSOs). This has led to the suggestion that a significant fraction of even the absorption systems with {beta} as high as {approx}0.1 may have been ejected by the relativistic jets in the blazars, which are expected to be pointed close to our direction. Here, we investigate this scenario using a large sample of 115 flat-spectrum radio-loud quasars (FSRQs) that also possess powerful jets, but are only weakly polarized. We show, for the first time, that dN/dz toward FSRQs is, on the whole, quite similar to that known for QSOs and that the comparative excess of strong Mg II absorption systems seen toward blazars is mainly confined to {beta} < 0.15. The excess relative to FSRQs probably results from a likely closer alignment of blazar jets with our direction; hence, any gas clouds accelerated by them are more likely to be on the line of sight to the active quasar nucleus.

  7. Ultraviolet absorption spectrum of hydrogen peroxide vapor. [for atmospheric abundances

    NASA Technical Reports Server (NTRS)

    Molina, L. T.; Schinke, S. D.; Molina, M. J.

    1977-01-01

    The ultraviolet absorption cross sections of hydrogen peroxide vapor have been determined over the wavelength range 210 to 350 nm at 296 K. At the longer wavelengths, the gas phase absorptivities are significantly larger than the corresponding values in condensed phase. The atmospheric H2O2 photodissociation rate for overhead sun at the earth's surface is estimated to be about 1.3 x 10 to the -5th/sec.

  8. Methane absorption variations in the spectrum of Pluto

    SciTech Connect

    Buie, M.W.; Fink, U.

    1987-06-01

    The lightcurve phases of 0.18, 0.35, 0.49, and 0.98 covered by 5600-10,500 A absolute spectrophotometry of Pluto during four nights include minimum (0.98) light and one near-maximum (0.49) light. The spectra are noted to exhibit significant methane band absorption depth variations at 6200, 7200, 7900, 8400, 8600, 8900, and 10,000 A, with the minimum absorption occurring at minimum light and thereby indicating a 30-percent change in the methane column abundance in the course of three days. An attempt is made to model this absorption strength variation with rotational phase terms of an isotropic surface distribution of methane frost and a clear layer of CH4 gas. 34 references.

  9. Optical absorption components of light-modulated absorption spectrum of CdS

    NASA Technical Reports Server (NTRS)

    Conway, E. J.; Long, E. R.

    1975-01-01

    The amplitude and decay coefficient of light-induced modulation of absorption (LIMA) was measured as a function of wavelength from 535 to 850 nm for single-crystal CdS. The decay coefficient exhibited a discontinuous resonance at 710 nm which was due to the overlap and cancellation of two opposing absorption changes. A method was developed to separate these opposing absorption changes using the measured decay coefficients. The discrete-level-to-band energy for one absorption change was found to be 1.64 eV. An improved model was developed which contains two associated levels in the band gap separated by 0.32 eV.

  10. The interstellar absorption-line spectrum of Mu Ophiuchi

    NASA Technical Reports Server (NTRS)

    Cardelli, J.; Boehm-Vitense, E.

    1982-01-01

    UV interstellar lines have been measured on high-resolution, long- and short-wavelength IUE spectra of the B8 V star Mu Oph. Column densities for the observed atoms and ions have been determined as well as turbulent velocities. The interstellar spectrum of Mu Oph is similar to the ones for Rho Oph and Zeta Oph. The ionization equilibria of several elements give consistent limits for the electron density. The C I line arising from different fine-structure levels are studied to yield estimates on the physical conditions in the cloud. Relative depletion of elements in the cloud seen in the interstellar spectrum of Mu Oph follows the same pattern as seen in the interstellar spectra of Zeta Oph and six other stars in the Rho Oph cloud complex.

  11. Influence of nanorod absorption spectrum width on superluminality effect for laser pulse propagation

    NASA Astrophysics Data System (ADS)

    Trofimov, Vyacheslav A.; Lysak, Tatiana M.

    2016-03-01

    We investigate the influence of the finite absorption spectrum width on the soliton formation and superluminality phenomenon at a femtosecond pulse propagation in a medium with noble nanoparticles. These effects take place if a positive phase-amplitude grating is induced by laser radiation. We take into account the two-photon absorption (TPA) of laser radiation by nanorods, and time-dependent nanorod aspect ratio changing due to their melting or reshaping because of laser energy absorption, and the nanorod absorption spectrum width. On the basis of computer simulation we demonstrate these effects in a medium with positive phase-amplitude grating, induced by laser radiation, if a weak laser energy absorption takes place on the laser pulse dispersion length.

  12. Absorption spectrum analysis based on singular value decomposition for photoisomerization and photodegradation in organic dyes

    NASA Astrophysics Data System (ADS)

    Kawabe, Yutaka; Yoshikawa, Toshio; Chida, Toshifumi; Tada, Kazuhiro; Kawamoto, Masuki; Fujihara, Takashi; Sassa, Takafumi; Tsutsumi, Naoto

    2015-10-01

    In order to analyze the spectra of inseparable chemical mixtures, many mathematical methods have been developed to decompose them into the components relevant to species from series of spectral data obtained under different conditions. We formulated a method based on singular value decomposition (SVD) of linear algebra, and applied it to two example systems of organic dyes, being successful in reproducing absorption spectra assignable to cis/trans azocarbazole dyes from the spectral data after photoisomerization and to monomer/dimer of cyanine dyes from those during photodegaradation process. For the example of photoisomerization, polymer films containing the azocarbazole dyes were prepared, which have showed updatable holographic stereogram for real images with high performance. We made continuous monitoring of absorption spectrum after optical excitation and found that their spectral shapes varied slightly after the excitation and during recovery process, of which fact suggested the contribution from a generated photoisomer. Application of the method was successful to identify two spectral components due to trans and cis forms of azocarbazoles. Temporal evolution of their weight factors suggested important roles of long lifetimed cis states in azocarbazole derivatives. We also applied the method to the photodegradation of cyanine dyes doped in DNA-lipid complexes which have shown efficient and durable optical amplification and/or lasing under optical pumping. The same SVD method was successful in the extraction of two spectral components presumably due to monomer and H-type dimer. During the photodegradation process, absorption magnitude gradually decreased due to decomposition of molecules and their decaying rates strongly depended on the spectral components, suggesting that the long persistency of the dyes in DNA-complex related to weak tendency of aggregate formation.

  13. An absorption line in the ultraviolet spectrum of 40 Eridani B

    NASA Technical Reports Server (NTRS)

    Greenstein, J. L.

    1980-01-01

    Two excellent low-resolution spectra show an absorption line of equivalent width 3 A, near 1391 A, in the typical DA (hydrogen atmosphere) white dwarf 40 Eri B. The line is confirmed by a high-resolution spectrum and is the first seen in any DA star. Ultraviolet fluxes and the profile of Lyman-alpha confirm an effective temperature near 17,000 K. If the line is Si IV, it requires a temperature near 40,000 K. Unattractive possibilities are a hot circumstellar absorbing envelope dependent on accretion from companions, or formation at large optical depth in a transparent atmosphere with high Si/H. A suggestion that H2 should be considered leads to the possible interpretation as the (0, 5) transition of the Lyman band, formed at small optical depth. The band should be stronger in cooler DAs.

  14. Absorption features in the x-ray spectrum of an ordinary radio pulsar.

    PubMed

    Kargaltsev, Oleg; Durant, Martin; Misanovic, Zdenka; Pavlov, George G

    2012-08-24

    The vast majority of known nonaccreting neutron stars (NSs) are rotation-powered radio and/or γ-ray pulsars. So far, their multiwavelength spectra have all been described satisfactorily by thermal and nonthermal continuum models, with no spectral lines. Spectral features have, however, been found in a handful of exotic NSs and were thought to be a manifestation of their unique traits. Here, we report the detection of absorption features in the x-ray spectrum of an ordinary rotation-powered radio pulsar, J1740+1000. Our findings bridge the gap between the spectra of pulsars and other, more exotic, NSs, suggesting that the features are more common in the NS spectra than they have been thought so far. PMID:22923576

  15. Mutational spectrum of Barrett's stem cells suggests paths to initiation of a precancerous lesion

    PubMed Central

    Yamamoto, Yusuke; Wang, Xia; Bertrand, Denis; Kern, Florian; Zhang, Ting; Duleba, Marcin; Srivastava, Supriya; Khor, Chiea Chuen; Hu, Yuanyu; Wilson, Lane H.; Blaszyk, Hagen; Rolshud, Daniil; Teh, Ming; Liu, Jianjun; Howitt, Brooke E.; Vincent, Matthew; Crum, Christopher P.; Nagarajan, Niranjan; Ho, Khek Yu; McKeon, Frank; Xian, Wa

    2016-01-01

    The precancerous lesion known as Barrett's oesophagus can evolve to oesophageal adenocarcinoma in decades-long processes of regenerative growth. Here we report the isolation and propagation of distinct, patient-matched stem cells of Barrett's, gastric and oesophageal epithelia that yield divergent tumour types following in vitro transformation and xenografting. Genomic analyses reveal a broad mutational spectrum unique to Barrett's stem cells that likely reflects their risk for oncogenesis. Remarkably, 25% of cases show no cancer-related genomic changes, suggesting that Barrett's initiates without driver mutations. Most cases, however, sustain patterns of deletions almost identical to adenocarcinoma though tumour-associated gene amplifications were absent. Notably, those suspected of low-grade dysplasia have p53 mutations or undergo amplifications of proto-oncogenes and receptor tyrosine kinases, implicating these events in lethal transitions. Our findings suggest paths for the initiation and progression of Barrett's and define a discrete stem cell underlying its regenerative growth whose eradication could prevent oesophageal adenocarcinoma. PMID:26783136

  16. Complex Resonance Absorption Structure in the X-Ray Spectrum of IRAS 13349+2438

    NASA Technical Reports Server (NTRS)

    Sako, M.; Kahn, S. M.; Behar, E.; Kaastra, J. S.; Brinkman, A. C.; Boller, Th.; Puchnarewicz, E. M.; Starling, R.; Liedahl, D. A.; Clavel, J.

    2000-01-01

    The luminous infrared-loud quasar IRAS 13349+2438 was observed with the XMM - Newton Observatory as part of the Performance Verification program. The spectrum obtained by the Reflection Grating Spectrometer (RGS) exhibits broad (FWHM - 1400 km/s) absorption lines from highly ionized elements including hydrogen- and helium-like carbon, nitrogen, oxygen, and neon, and several iron L - shell ions (Fe XVII - XX). Also shown in the spectrum is the first astrophysical detection of a broad absorption feature around lambda = 16 - 17 A identified as an unresolved transition array (UTA) of 2p - 3d inner-shell absorption by iron M-shell ions in a much cooler medium; a feature that might be misidentified as an O VII edge when observed with moderate resolution spectrometers. No absorption edges are clearly detected in the spectrum. We demonstrate that the RGS spectrum of IRAS 13349+2438 exhibits absorption lines from two distinct regions, one of which is tentatively associated with the medium that produces the optical/UV reddening.

  17. Two-photon absorption spectrum of the photoinitiator Lucirin TPO-L

    NASA Astrophysics Data System (ADS)

    Mendonca, C. R.; Correa, D. S.; Baldacchini, T.; Tayalia, P.; Mazur, E.

    2008-03-01

    Two-photon absorption induced polymerization provides a powerful method for the fabrication of intricate three-dimensional microstructures. Recently, Lucirin TPO-L was shown to be a photoinitiator with several advantageous properties for two-photon induced polymerization. Here we measure the two-photon absorption cross-section spectrum of Lucirin TPO-L, which presents a maximum of 1.2 GM at 610 nm. Despite its small two-photon absorption cross-section, it is possible to fabricate excellent microstructures by two-photon polymerization due to the high polymerization quantum yield of Lucirin TPO-L. These results indicate that optimization of the two-photon absorption cross-section is not the only material parameter to be considered when searching for new photoinitiators for microfabrication via two-photon absorption.

  18. Ab initio calculation of the electronic absorption spectrum of liquid water

    NASA Astrophysics Data System (ADS)

    Martiniano, Hugo F. M. C.; Galamba, Nuno; Cabral, Benedito J. Costa

    2014-04-01

    The electronic absorption spectrum of liquid water was investigated by coupling a one-body energy decomposition scheme to configurations generated by classical and Born-Oppenheimer Molecular Dynamics (BOMD). A Frenkel exciton Hamiltonian formalism was adopted and the excitation energies in the liquid phase were calculated with the equation of motion coupled cluster with single and double excitations method. Molecular dynamics configurations were generated by different approaches. Classical MD were carried out with the TIP4P-Ew and AMOEBA force fields. The BLYP and BLYP-D3 exchange-correlation functionals were used in BOMD. Theoretical and experimental results for the electronic absorption spectrum of liquid water are in good agreement. Emphasis is placed on the relationship between the structure of liquid water predicted by the different models and the electronic absorption spectrum. The theoretical gas to liquid phase blue-shift of the peak positions of the electronic absorption spectrum is in good agreement with experiment. The overall shift is determined by a competition between the O-H stretching of the water monomer in liquid water that leads to a red-shift and polarization effects that induce a blue-shift. The results illustrate the importance of coupling many-body energy decomposition schemes to molecular dynamics configurations to carry out ab initio calculations of the electronic properties in liquid phase.

  19. Ab initio calculation of the electronic absorption spectrum of liquid water

    SciTech Connect

    Martiniano, Hugo F. M. C.; Galamba, Nuno; Cabral, Benedito J. Costa

    2014-04-28

    The electronic absorption spectrum of liquid water was investigated by coupling a one-body energy decomposition scheme to configurations generated by classical and Born-Oppenheimer Molecular Dynamics (BOMD). A Frenkel exciton Hamiltonian formalism was adopted and the excitation energies in the liquid phase were calculated with the equation of motion coupled cluster with single and double excitations method. Molecular dynamics configurations were generated by different approaches. Classical MD were carried out with the TIP4P-Ew and AMOEBA force fields. The BLYP and BLYP-D3 exchange-correlation functionals were used in BOMD. Theoretical and experimental results for the electronic absorption spectrum of liquid water are in good agreement. Emphasis is placed on the relationship between the structure of liquid water predicted by the different models and the electronic absorption spectrum. The theoretical gas to liquid phase blue-shift of the peak positions of the electronic absorption spectrum is in good agreement with experiment. The overall shift is determined by a competition between the O–H stretching of the water monomer in liquid water that leads to a red-shift and polarization effects that induce a blue-shift. The results illustrate the importance of coupling many-body energy decomposition schemes to molecular dynamics configurations to carry out ab initio calculations of the electronic properties in liquid phase.

  20. Research on filling process of fuel and oxidant during detonation based on absorption spectrum technology

    NASA Astrophysics Data System (ADS)

    Lv, Xiao-Jing; Li, Ning; Weng, Chun-Sheng

    2014-12-01

    Research on detonation process is of great significance for the control optimization of pulse detonation engine. Based on absorption spectrum technology, the filling process of fresh fuel and oxidant during detonation is researched. As one of the most important products, H2O is selected as the target of detonation diagnosis. Fiber distributed detonation test system is designed to enable the detonation diagnosis under adverse conditions in detonation process. The test system is verified to be reliable. Laser signals at different working frequency (5Hz, 10Hz and 20Hz) are detected. Change of relative laser intensity in one detonation circle is analyzed. The duration of filling process is inferred from the change of laser intensity, which is about 100~110ms. The peak of absorption spectrum is used to present the concentration of H2O during the filling process of fresh fuel and oxidant. Absorption spectrum is calculated, and the change of absorption peak is analyzed. Duration of filling process calculated with absorption peak consisted with the result inferred from the change of relative laser intensity. The pulse detonation engine worked normally and obtained the maximum thrust at 10Hz under experiment conditions. The results are verified through H2O gas concentration monitoring during detonation.

  1. [Study on removing the lamp spectrum structure in differential optical absorption spectroscopy].

    PubMed

    Qu, Xiao-ying; Li, Yu-jin

    2010-11-01

    Differential optical absorption spectroscopy (DOAS) technique has been used to measure trace gases in the atmosphere by their strongly structured absorption of radiation in the UV and visible spectral range, and nowadays this technique has been widely utilized to measure trace polluted gases in the atmosphere e.g. SO2, NO2, O3, HCHO, etc. However, there exists lamp (xenon lamp or deuteriumlamp) spectrum structure in the measured band (300-700 nm) of the absorption spectra of atmosphere, which badly impacts on precision of retrieving the concentration of trace gases in the atmosphere. People home and abroad generally employ two ways to handle this problem, one is segmenting band retrieving method, another is remedial retrieving method. In the present paper, a new retrieving method to deal with this trouble is introduced. The authors used moving-window average smoothing method to obtain the slow part of the absorption spectra of atmosphere, then achieved the lamp (xenon lamp in the paper) spectrum structure in the measured band of the absorption spectra of atmosphere. The authors analyzed and retrieved the measured spectrum of the atmosphere, and the result is better than the forenamed ways. Chi-square of residuum is 2.995 x 10(-4), and this method was proved to be able to avoid shortcoming of choosing narrowband and disadvantage of discovering the new component of atmosphere in retrieving the concentration of air pollutants and measuring the air pollutants. PMID:21284148

  2. Selectivity of the optical-absorption method based on an instrumental pick out of Fourier components in the absorption spectrum

    NASA Astrophysics Data System (ADS)

    Pisarevsky, Yu. V.; Kolesnikov, S. A.; Kolesnikova, E. S.; Turutin, Yu. A.; Konopelko, L. A.; Shor, N. B.

    2016-06-01

    The introduction of interference-polarization filters (IPFs) in the structure of an optical-absorption analyzer makes it possible to pick out a harmonic (a Fourier component of the absorption spectrum) providing measurement with the highest sensitivity. The selectivity of such a method of analysis is determined by overlapping the oscillations of the measured and interfering components. By the example of measurement in benzene in the presence of an interfering component (toluene), the possibility is considered for the optimization of selectivity due to the variation of the path-difference dispersion for ordinary and extraordinary interfering rays. The metrological characteristics of the interference-polarization analyzer of C6H6 confirming the results of calculations are given.

  3. [Effects of LED spectrum combinations on the absorption of mineral elements of hydroponic lettuce].

    PubMed

    Chen, Xiao-Li; Guo, Wen-Zhong; Xue, Xu-Zhang; Mmanake Beauty, Morewane

    2014-05-01

    Lettuce (Lactuca sativa) was hydroponically cultured in a completely enclosed plant factory, in which spectrum proportion-adjustable LED panels were used as sole light source for plant growth. Absorption and content of eleven mineral elements such as K, P, Ca, Mg, Na, Fe, Mn, Zn, Cu, B and Mo in Lactuca sativa under different spectral component conditions were studied by ICP -AES technology. The results showed that: (1) Single or combined spectrums corresponding to the absorbing peaks of chlorophyll a and b (450, 660 nm) could enhance the absorbing ability of roots especially for mineral elements Na, Fe, Mn, Cu and Mo, the single red spectrum had the most significant promoting effect under which contents of those four elements were respectively 7. 8, 4. 2, 4. 0 and 3. 7 times more than that under FL; (2) Absorption of K and B was the highest under FL which was 10. 309 mg g-1 and 32. 6 microg g-1 while the values decreased significantly under single or combined spectrum of red and blue; (3) Plants grown under single blue spectrum had the lowest absorption of Ca and Mg which respectively decreased by 35% and 33% than FL; (4) Lettuce grown under the spectrum combination of 30% blue and 70% red had the highest accumulations of biomass while those grown under 20% blue and 80% red had the highest accumulations of the following seven elements Ca, Mg, Na, Fe, Mn, Zn and B. The results provided theoretical basis for adjusting nutrient solution formula and selecting light spectrum of hydroponic lettuce. PMID:25095445

  4. Tunable ultranarrow spectrum selective absorption in a graphene monolayer at terahertz frequency

    NASA Astrophysics Data System (ADS)

    Wu, Jun

    2016-06-01

    Complete absorption in a graphene monolayer at terahertz frequency through the critical coupling effect is investigated. It is achieved by sandwiching the graphene monolayer between a dielectric grating and a Bragg grating. The designed graphene absorber exhibits near-unity absorption at resonance but with an ultranarrow spectrum and antenna-like response, which is attributed to the combined effects of guided mode resonance with dielectric grating and the photonic band gap with Bragg grating. In addition to numerical simulation, the electric field distributions are also illustrated to provide a physical understanding of the perfect absorption effect. Furthermore, the absorption performance can be tuned by only changing the Fermi level of graphene, which is beneficial for real application. It is believed that this study may be useful for designing next-generation graphene-based optoelectronic devices.

  5. Considering Homeschooling Your Child on the Autism Spectrum? Some Helpful Hints and Suggestions for Parents

    ERIC Educational Resources Information Center

    Hurlbutt, Karen

    2010-01-01

    With the increase in the numbers of diagnosed children on the autism spectrum, schools are being challenged to provide proper educational services for these children. In Educating Children with Autism, the National Research Council recommended that educational programs for students with autism include three basic components. These are direct…

  6. Absorption spectrum of NO in the {gamma}(O, O) band

    SciTech Connect

    Zobnin, A.V.; Korotkov, A.N.

    1995-05-01

    A promising technique for determining the concentration of nitrogen oxide in the air of an industrial zone and in process gases is the measurement of the absorption of UV radiation by this molecule in the {gamma}(O,O) band with the center of {lambda}{sub 0} = 226.5 nm. This band corresponds to the transition X{sup 2}{Pi}{yields}{Alpha}{sup 2}{Sigma} of the NO molecule and is characterized by a complex rotational structure consisting of about 400 lines. This structure cannot be resolved completely by most spectral instruments. However, if the width of the spread function of the device is perceptibly smaller than the width of the given absorption band ({approx_equal}2 nm), but larger than the characteristic space between rotational lines ({approx_equal}0.02 nm), then the recorded transmission spectra of NO are almost insensitive to a change in the form of this function. In the given case, to describe the transmission spectrum it is possible to use the absorption coefficient averaged over rotational lines. And even though the Bouger-Lambert-Beer law is not strictly applicable for this spectrum, the dependence of the transmission spectrum of NO on the optical thickness, temperature, and pressure of the broadening gas can be represented in the form of an empirical dependence that can be useful in practice, for example, when processing the absorption spectra recorded by dispersion gas analyzers. Thus, the need for complex and laborious calculations is avoided, and this simplifies considerably the instrumental implementation of this method of measuring the concentration of NO. The object of the present work is to determine the empirical dependence of the absorption spectrum of NO in the {gamma}(O, O) band on the optical thickness, temperature, and pressure of the broadening gas in the ranges most frequently encountered in operation of dispersion gas analyzers.

  7. Absorption lines in the spectrum of Q0248 + 4302 due to a foreground tidal tail

    SciTech Connect

    Sargent, W.L.W.; Steidel, C.C. California Univ., Berkeley )

    1990-08-01

    The strong absorption lines in the spectrum of the quasar Q0248 + 4302 are discussed. The absorption has been shown to be produced in a sinuous tidal tail which emanates from the nearby galaxy pair G0248 + 4302A,B. There is a velocity difference of about 260 km/s between the systemic redshift of the interacting galaxies and the redshift of the tidal tail at a galactocentric distance of about 11/h kpc. The large velocity spread observed in the tail gas is probably responsible for the unusual strength of the interstellar lines. 18 refs.

  8. Absorption-line profiles in a companion spectrum of a mass-losing cool supergiant

    NASA Technical Reports Server (NTRS)

    Rodrigues, Liliya L.; Boehm-Vitense, Erika

    1992-01-01

    Cool star winds can best be observed in resonance absorption lines seen in the spectrum of a hot companion, due to the wind passing in front of the blue star. We calculated absorption line profiles that would be seen in the ultraviolet part of the blue companion spectrum. Line profiles are derived for different radial dependences of the cool star wind and for different orbital phases of the binary. Bowen and Wilson find theoretically that stellar pulsations drive mass loss. We therefore apply our calculations to the Cepheid binary S Muscae which has a B5V companion. We find an upper limit for the Cepheid mass loss of M less than or equal to 7 x 10 (exp -10) solar mass per year provided that the stellar wind of the companion does not influence the Cepheid wind at large distances.

  9. Absorption line profiles in a companion spectrum of a mass losing cool supergiant

    NASA Technical Reports Server (NTRS)

    Rodrigues, Liliya L.; Boehm-Vitense, Erika

    1990-01-01

    Cool star winds can best be observed in resonance absorption lines seen in the spectrum of a hot companion, due to the wind passing in front of the blue star. We calculated absorption line profiles that would be seen in the ultraviolet part of the blue companion spectrum. Line profiles are derived for different radial dependences of the cool star wind and for different orbital phases of the binary. Bowen and Wilson find theoretically that stellar pulsations drive mass loss. We therefore apply our calculations to the Cepheid binary S Muscae which has a B5V companion. We find an upper limit for the Cepheid mass loss of M less than or equal to 7 x 10(exp -10) solar mass per year provided that the stellar wind of the companion does not influence the Cepheid wind at large distances.

  10. Integration of Semiconducting Sulfides for Full-Spectrum Solar Energy Absorption and Efficient Charge Separation.

    PubMed

    Zhuang, Tao-Tao; Liu, Yan; Li, Yi; Zhao, Yuan; Wu, Liang; Jiang, Jun; Yu, Shu-Hong

    2016-05-23

    The full harvest of solar energy by semiconductors requires a material that simultaneously absorbs across the whole solar spectrum and collects photogenerated electrons and holes separately. The stepwise integration of three semiconducting sulfides, namely ZnS, CdS, and Cu2-x S, into a single nanocrystal, led to a unique ternary multi-node sheath ZnS-CdS-Cu2-x S heteronanorod for full-spectrum solar energy absorption. Localized surface plasmon resonance (LSPR) in the nonstoichiometric copper sulfide nanostructures enables effective NIR absorption. More significantly, the construction of pn heterojunctions between Cu2-x S and CdS leads to staggered gaps, as confirmed by first-principles simulations. This band alignment causes effective electron-hole separation in the ternary system and hence enables efficient solar energy conversion. PMID:27062543

  11. Light-induced changes in the absorption spectrum of bacteriorhodopsin under two-wavelength excitation

    NASA Astrophysics Data System (ADS)

    Koklyushkin, A. V.; Korolev, A. E.

    2004-09-01

    The results of spectrophotometric measurements of nonlinear light-induced changes in the absorption spectrum of bacteriorhodopsin D96N occurring upon simultaneous excitation at the wavelengths 633 and 441 nm in the excitation intensity range typical for recording of dynamic holograms are presented. The quantitative conditions under which the action of the radiation at one wavelength reduces the change in the optical density caused by the radiation at the other wavelength are determined.

  12. THE SURPRISING ABSENCE OF ABSORPTION IN THE FAR-ULTRAVIOLET SPECTRUM OF Mrk 231

    SciTech Connect

    Veilleux, S.; Trippe, M.; Krug, H.; Hamann, F.; Rupke, D. S. N.; Tripp, T. M.; Netzer, H.; Lutz, D.; Genzel, R.; Sturm, E.; Tacconi, L.; Sembach, K. R.; Teng, S. H.; Maiolino, R. E-mail: veilleux@astro.umd.edu

    2013-02-10

    Mrk 231, the nearest (z = 0.0422) quasar, hosts both a galactic-scale wind and a nuclear-scale iron low-ionization broad absorption line (FeLoBAL) outflow. We recently obtained a far-ultraviolet (FUV) spectrum of this object covering {approx}1150-1470 A with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. This spectrum is highly peculiar, highlighted by the presence of faint ({approx}<2% of predictions based on H{alpha}), broad ({approx}>10,000 km s{sup -1} at the base), and highly blueshifted (centroid at {approx} -3500 km s{sup -1}) Ly{alpha} emission. The FUV continuum emission is slightly declining at shorter wavelengths (consistent with F {sub {lambda}}{proportional_to}{lambda}{sup 1.7}) and does not show the presence of any obvious photospheric or wind stellar features. Surprisingly, the FUV spectrum also does not show any unambiguous broad absorption features. It thus appears to be dominated by the AGN, rather than hot stars, and virtually unfiltered by the dusty FeLoBAL screen. The observed Ly{alpha} emission is best explained if it is produced in the outflowing BAL cloud system, while the Balmer lines arise primarily from the standard broad emission line region seen through the dusty (A{sub V} {approx} 7 mag) broad absorption line region. Two possible geometric models are discussed in the context of these new results.

  13. The Surprising Absence of Absorption in the Far-ultraviolet Spectrum of Mrk 231

    NASA Technical Reports Server (NTRS)

    Veilleux, S.; Trippe, M.; Hamann, F.; Rupke, D. S. N.; Tripp, T. M.; Netzer, H.; Lutz, D.; Sembach, K. R.; Krug, H.; Teng, Stacy H.; Genzel, R.; Maiolino, R.; Sturm, E.; Tacconi, L.

    2013-01-01

    Mrk 231, the nearest (z = 0.0422) quasar, hosts both a galactic-scale wind and a nuclear-scale iron low-ionization broad absorption line (FeLoBAL) outflow. We recently obtained a far-ultraviolet (FUV) spectrum of this object covering approx. 1150-1470A with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. This spectrum is highly peculiar, highlighted by the presence of faint (< or approx.2% of predictions based on H(alpha)), broad (> or approx.10,000 km/s at the base), and highly blueshifted (centroid at approx. 3500 km/s) Ly(aplpha) emission. The FUV continuum emission is slightly declining at shorter wavelengths (consistent with F(sub lambda) Alpha Lambda(sup 1.7)) and does not show the presence of any obvious photospheric or wind stellar features. Surprisingly, the FUV spectrum also does not show any unambiguous broad absorption features. It thus appears to be dominated by the AGN, rather than hot stars, and virtually unfiltered by the dusty FeLoBAL screen. The observed Ly(alpha) emission is best explained if it is produced in the outflowing BAL cloud system, while the Balmer lines arise primarily from the standard broad emission line region seen through the dusty (Av approx. 7 mag) broad absorption line region. Two possible geometric models are discussed in the context of these new results.

  14. Ultraviolet Absorption Spectrum of Malonaldehyde in Water Is Dominated by Solvent-Stabilized Conformations

    SciTech Connect

    Xu, Xuefei; Zheng, Jingjing; Truhlar, Donald G.

    2015-07-01

    Free energy calculations for eight enol isomers of malonaldehyde (MA) and simulation of the ultraviolet (UV) absorption spectrum in both the gas phase and water (pH = 3, where the molecule exists in neutral undeprotonated form) show that in water the two s-trans nonchelated enol conformers of MA become thermodynamically more stable than the internally hydrogen-bonded (“chelated enol”) conformer (CE). The pure CE conformer in water has a slightly red-shifted UV spectrum with respect to that in the gas phase, but the blue-shifted spectrum observed in water at pH 3 is dominated by solvent-stabilized conformations that have negligible populations in the gas phase. Density functional calculations with the solvation model based on density (SMD) and an ensemble-averaged vertical excitation model explain the experimental observations in detail.

  15. Electronic structure and absorption spectrum of biexciton obtained by using exciton basis

    SciTech Connect

    Shiau, Shiue-Yuan; Combescot, Monique; Chang, Yia-Chung

    2013-09-15

    We approach the biexciton Schrödinger equation not through the free-carrier basis as usually done, but through the free-exciton basis, exciton–exciton interactions being treated according to the recently developed composite boson many-body formalism which allows an exact handling of carrier exchange between excitons, as induced by the Pauli exclusion principle. We numerically solve the resulting biexciton Schrödinger equation with the exciton levels restricted to the ground state and we derive the biexciton ground state as well as the bound and unbound excited states as a function of hole-to-electron mass ratio. The biexciton ground-state energy we find, agrees reasonably well with variational results. Next, we use the obtained biexciton wave functions to calculate optical absorption in the presence of a dilute exciton gas in quantum well. We find an asymmetric peak with a characteristic low-energy tail, identified with the biexciton ground state, and a set of Lorentzian-like peaks associated with biexciton unbound states, i.e., exciton–exciton scattering states. Last, we propose a pump–probe experiment to probe the momentum distribution of the exciton condensate. -- Highlights: •New composite boson many-body theory is used to derive exactly the biexciton Schrödinger equation using the exciton basis. •We solved the 2D and 3D biexciton ground- and excited-state binding energies for various electron-to-hole mass ratios. •The absorption spectrum shows an asymmetric low-energy peak identified with the biexciton ground state. •High-energy Lorentzian-like peaks in the absorption spectrum are associated with the exciton–exciton scattering states. •The exciton gas momentum distribution can be determined by the absorption spectrum via the biexciton wave functions.

  16. Hydrogen sulfide absorption spectrum in the 5700-6600 cm-1 spectral region

    NASA Astrophysics Data System (ADS)

    Brown, L. R.; Naumenko, O. V.; Polovtseva, E. R.; Sinitsa, Leonid N.

    2004-01-01

    High resolution FT absorption spectrum of H2S from 5700 to 6600 cm-1 was experimentally recorded and theoretically treated. As a result of the spectrum assignment 1100 precise energy levels were derived for the 2nd hexad interacting states of H232S, H233S, and H234S isotope species including the highly excited (050) state. These energy levels were modeled using Watson-type rotational Hamiltonian and taking into account Coriolis, Darling-Dennison and weak Fermi-resonance interactions inside polyad of interacting states. An average accuracy of the energy levels fitting is of 0.0019 cm-1 for the main isotope species. New evaluation of the band origin of the dark (012) state Ev = 6385.299cm-1 is obtained from the fitting process which agrees well with recent prediction by Naumenko et al. (J. Mol. Spectrosc. 50, 100-110 (2001)). Precise line intensity measurements were performed for more than 1200 absorption lines with accuracy varying from 1 to 7%. These intensities were modeled within 3.3% using wavefunctions derived in the process of the energy levels fitting. The transformed transition moment expansion with 29 terms for 1088 intensities was used. Detailed and accurate H2S absorption line list was generated in the HITRAN format for the analyzed spectral region.

  17. UV absorption spectrum of the C2 Criegee intermediate CH{sub 3}CHOO

    SciTech Connect

    Smith, Mica C.; Ting, Wei-Lun; Chang, Chun-Hung; Takahashi, Kaito; Boering, Kristie A.; Lin, Jim Jr-Min

    2014-08-21

    The UV spectrum of CH{sub 3}CHOO was measured by transient absorption in a flow cell at 295 K. The absolute absorption cross sections of CH{sub 3}CHOO were measured by laser depletion in a molecular beam to be (1.06 ± 0.09) × 10{sup −17} cm{sup 2} molecule{sup −1} at 308 nm and (9.7 ± 0.6) × 10{sup −18} cm{sup 2} molecule{sup −1} at 352 nm. After scaling the UV spectrum of CH{sub 3}CHOO to the absolute cross section at 308 nm, the peak UV cross section is (1.27 ± 0.11) × 10{sup −17} cm{sup 2} molecule{sup −1} at 328 nm. Compared to the simplest Criegee intermediate CH{sub 2}OO, the UV absorption band of CH{sub 3}CHOO is similar in intensity but blue shifted by 14 nm, resulting in a 20% slower photolysis rate estimated for CH{sub 3}CHOO in the atmosphere.

  18. UV absorption spectrum of the C2 Criegee intermediate CH3CHOO.

    PubMed

    Smith, Mica C; Ting, Wei-Lun; Chang, Chun-Hung; Takahashi, Kaito; Boering, Kristie A; Lin, Jim Jr-Min

    2014-08-21

    The UV spectrum of CH3CHOO was measured by transient absorption in a flow cell at 295 K. The absolute absorption cross sections of CH3CHOO were measured by laser depletion in a molecular beam to be (1.06 ± 0.09) × 10(-17) cm(2) molecule(-1) at 308 nm and (9.7 ± 0.6) × 10(-18) cm(2) molecule(-1) at 352 nm. After scaling the UV spectrum of CH3CHOO to the absolute cross section at 308 nm, the peak UV cross section is (1.27 ± 0.11) × 10(-17) cm(2) molecule(-1) at 328 nm. Compared to the simplest Criegee intermediate CH2OO, the UV absorption band of CH3CHOO is similar in intensity but blue shifted by 14 nm, resulting in a 20% slower photolysis rate estimated for CH3CHOO in the atmosphere. PMID:25149781

  19. Infrared absorption spectrum of the simplest deuterated Criegee intermediate CD2OO

    NASA Astrophysics Data System (ADS)

    Huang, Yu-Hsuan; Nishimura, Yoshifumi; Witek, Henryk A.; Lee, Yuan-Pern

    2016-07-01

    We report a transient infrared (IR) absorption spectrum of the simplest deuterated Criegee intermediate CD2OO recorded using a step-scan Fourier-transform spectrometer coupled with a multipass absorption cell. CD2OO was produced from photolysis of flowing mixtures of CD2I2, N2, and O2 (13 or 87 Torr) with laser light at 308 nm. The recorded spectrum shows close structural similarity with the spectrum of CH2OO reported previously [Y.-T. Su et al., Science 340, 174 (2013)]. The four bands observed at 852, 1017, 1054, and 1318 cm-1 are assigned to the OO stretching mode, two distinct in-plane OCD bending modes, and the CO stretching mode of CD2OO, respectively, according to vibrational wavenumbers, IR intensities, rotational contours, and deuterium-isotopic shifts predicted with extensive quantum-chemical calculations. The CO-stretching mode of CD2OO at 1318 cm-1 is blue shifted from the corresponding band of CH2OO at 1286 cm-1; this can be explained by a mechanism based on mode mixing and isotope substitution. A band near 936 cm-1, observed only at higher pressure (87 Torr), is tentatively assigned to the CD2 wagging mode of CD2IOO.

  20. Infrared absorption spectrum of the simplest deuterated Criegee intermediate CD2OO.

    PubMed

    Huang, Yu-Hsuan; Nishimura, Yoshifumi; Witek, Henryk A; Lee, Yuan-Pern

    2016-07-28

    We report a transient infrared (IR) absorption spectrum of the simplest deuterated Criegee intermediate CD2OO recorded using a step-scan Fourier-transform spectrometer coupled with a multipass absorption cell. CD2OO was produced from photolysis of flowing mixtures of CD2I2, N2, and O2 (13 or 87 Torr) with laser light at 308 nm. The recorded spectrum shows close structural similarity with the spectrum of CH2OO reported previously [Y.-T. Su et al., Science 340, 174 (2013)]. The four bands observed at 852, 1017, 1054, and 1318 cm(-1) are assigned to the OO stretching mode, two distinct in-plane OCD bending modes, and the CO stretching mode of CD2OO, respectively, according to vibrational wavenumbers, IR intensities, rotational contours, and deuterium-isotopic shifts predicted with extensive quantum-chemical calculations. The CO-stretching mode of CD2OO at 1318 cm(-1) is blue shifted from the corresponding band of CH2OO at 1286 cm(-1); this can be explained by a mechanism based on mode mixing and isotope substitution. A band near 936 cm(-1), observed only at higher pressure (87 Torr), is tentatively assigned to the CD2 wagging mode of CD2IOO. PMID:27475359

  1. Surprises from a Deep ASCA Spectrum of the Broad Absorption Line Quasar PHL 5200

    NASA Technical Reports Server (NTRS)

    Mathur, Smita; Matt, G.; Green, P. J.; Elvis, M.; Singh, K. P.

    2002-01-01

    We present a deep (approx. 85 ks) ASCA observation of the prototype broad absorption line quasar (BALQSO) PHL 5200. This is the best X-ray spectrum of a BALQSO yet. We find the following: (1) The source is not intrinsically X-ray weak. (2) The line-of-sight absorption is very strong, with N(sub H) = 5 x 10(exp 23)/sq cm. (3) The absorber does not cover the source completely; the covering fraction is approx. 90%. This is consistent with the large optical polarization observed in this source, implying multiple lines of sight. The most surprising result of this observation is that (4) the spectrum of this BALQSO is not exactly similar to other radio-quiet quasars. The hard X-ray spectrum of PHL 5200 is steep, with the power-law spectral index alpha approx. 1.5. This is similar to the steepest hard X-ray slopes observed so far. At low redshifts, such steep slopes are observed in narrow-line Seyfert 1 (NLS1) galaxies, believed to be accreting at a high Eddington rate. This observation strengthens the analogy between BALQSOs and NLS1 galaxies and supports the hypothesis that BALQSOs represent an early evolutionary state of quasars. It is well accepted that the orientation to the line of sight determines the appearance of a quasar: age seems to play a significant role as well.

  2. [Application of near-infrared absorption spectrum scanning techniques in gas quantitative measurement].

    PubMed

    Ding, Hui; Liang, Jian-Qi; Cui, Jun-Hong; Wu, Xiang-Nan; Li, Xian-Li

    2010-03-01

    A practical gas sensing system utilizing absorption spectrum scanning techniques was developed. Using the narrow-band transmission of a fiber tunable filter (TOF) and wavelength modulation technique, the so-called cross-sensing effects of the traditional spectrum absorption based gas sensor were reduced effectively and thus the target gas was detected sensitively and selectively. In order to reduce the effects of nonlinearity of TOF on the measurement results and improve the system stability in operation, the reflection spectrum of a reference FBG was monitored and employed to control the modulation region and center of TOF wavelength precisely. Moreover, a kind of weak signal detecting circuits was developed to detect the weak response signal of the system with high sensitivity. The properties of the proposed system were demonstrated experimentally by detection of acetylene. Approximate linear relationships between the system responses and the input acetylene concentrations were demonstrated by experiments. The minimum detectable acetylene of 5 x 10(-6), with signal-noise ratio of 3, was also achieved by experiments. PMID:20496683

  3. NF3: UV Absorption Spectrum Temperature Dependence and the Atmospheric and Climate Forcing Implications

    NASA Technical Reports Server (NTRS)

    Papadimitriou, Vassileios C.; McGillen, Max R.; Fleming, Eric L.; Jackman, Charles H.; Burkholder, James B.

    2013-01-01

    Nitrogen trifluoride (NF3) is an atmospherically persistent greenhouse gas that is primarily removed by UV photolysis and reaction with O((sup 1)D) atoms. In this work, the NF3 gas-phase UV absorption spectrum, sigma(delta,T), was measured at 16 wavelengths between 184.95 and 250 nm at temperatures between 212 and 296 K. A significant spectrum temperature dependence was observed in the wavelength region most relevant to atmospheric photolysis (200-220 nm) with a decrease in sigma(210 nm,T) of approximately 45 percent between 296 and 212 K. Atmospheric photolysis rates and global annually averaged lifetimes of NF3 were calculated using the Goddard Space Flight Center 2-D model and the sigma(delta,T) parameterization developed in this work. Including the UV absorption spectrum temperature dependence increased the stratospheric photolysis lifetime from 610 to 762 years and the total global lifetime from 484 to 585 years; the NF3 global warming potentials on the 20-, 100-, and 500-year time horizons increased less than 0.3, 1.1, and 6.5 percent to 13,300, 17,700, and 19,700, respectively.

  4. Simulation of energy absorption spectrum in NaI crystal detector for multiple gamma energy using Monte Carlo method

    SciTech Connect

    Wirawan, Rahadi; Waris, Abdul; Djamal, Mitra; Handayani, Gunawan

    2015-04-16

    The spectrum of gamma energy absorption in the NaI crystal (scintillation detector) is the interaction result of gamma photon with NaI crystal, and it’s associated with the photon gamma energy incoming to the detector. Through a simulation approach, we can perform an early observation of gamma energy absorption spectrum in a scintillator crystal detector (NaI) before the experiment conducted. In this paper, we present a simulation model result of gamma energy absorption spectrum for energy 100-700 keV (i.e. 297 keV, 400 keV and 662 keV). This simulation developed based on the concept of photon beam point source distribution and photon cross section interaction with the Monte Carlo method. Our computational code has been successfully predicting the multiple energy peaks absorption spectrum, which derived from multiple photon energy sources.

  5. New transient absorption observed in the spectrum of colloidal CdSe nanoparticles pumped with high-power femtosecond pulses

    SciTech Connect

    Burda, C.; Link, S.; Green, T.C.; El-Sayed, M.A.

    1999-12-09

    The power dependence of the transient absorption spectrum of CdSe nanoparticle colloids with size distribution of 4.0 {+-} 0.4 nm diameter is studied with femtosecond pump-probe techniques. At the lowest pump laser power, the absorption bleaching (negative spectrum) characteristic of the exciton spectrum is observed with maxima at 560 and 480 nm. As the pump laser power increases, two new transient absorptions at 510 and 590 nm with unresolved fast rise (<100 fs) and long decay times ({much{underscore}gt}150 ps) are observed. The energy of each of the positive absorption is red shifted from that of the bleach bands by {approximately}120 MeV. The origin of this shift is discussed in terms of the effect of the internal electric field of the many electron-hole pairs formed within the quantum dot at the high pump intensity, absorption from a metastable excited state or the formation of biexcitons.

  6. The Far-Infrared Absorption Spectrum of Low Temperature Hydrogen Gas.

    NASA Astrophysics Data System (ADS)

    Wishnow, Edward Hyman

    The far-infrared absorption spectrum of normal hydrogen gas has been measured from 20-320 cm^ {-1} (lambda = 500-31 mu M), over the temperature range 21-38 K, and the pressure range 0.6-3 atmospheres. The spectra cover the very weak and broad collision-induced translational absorption band of H_2 which at these low temperatures is observed well isolated from the H_2 rotational lines. Translational absorption occurs when two molecules collide and absorb a photon via a transient induced dipole moment. The molecules emerge from the collision with altered translational energies, and the rotational, vibrational, and electronic energy states remain unaffected. The present spectra are the lowest temperature, lowest pressure, and highest resolution studies of the H_2 translational spectrum. In order to observe the weak translational absorption band, a long pathlength multireflection absorption cell ('White cell'), cooled by the continuous flow of helium vapour, has been designed and constructed. The cell has an f/10 optical beam that allows long wavelength radiation to be transmitted, with low diffraction losses, over an optical path of up to 60 m. The cell is coupled to a Fourier transform interferometer and H_2^ectra are obtained at a spectral resolution of 0.24 cm ^{-1}, 10 times higher than previous experiments. Low temperature absorption spectra are due to not only transitions between molecular translational energy states, but also rotational transitions between the bound states of the van der Waals complex formed by two hydrogen molecules. The integrated absorption of the measured H _2 translational spectrum is consistent with the binary absorption coefficient calculated using the Poll and Van Kranendonk theory of collison-induced absorption. The calculation is based on the quantum mechanical pair distribution function derived from the Lennard-Jones intermolecular potential, and it includes contributions from H_2 dimer bound states. Although dimer transitions

  7. [Detection technology of methane gas concentration based on infrared absorption spectrum].

    PubMed

    Luo, Da-Feng; Yang, Jian-Hua; Zhong, Chong-Gui

    2011-02-01

    According to the disadvantages of current methane sensor in coal mine, the infrared methane concentration detection system based on the principle of infrared spectrum absorption was designed using differential absorption technology. In the system single light beam absorbing cell and single light beam and double wavelengths technology are adopted. Differential amplifier circuit serves as the core of faint signal processing circuit that detects the output signal of methane concentration, and linear formula fits the curve of methane concentration and output voltage, which realizes accurate and full range detection of gas concentration. Experiment shows that measurement error is less than 2%, and the system has very high measurement precision and possesses the basis of industrial applications. PMID:21510386

  8. Blue satellites of absorption spectrum study of sodium based excimer-pumped alkali vapor laser

    NASA Astrophysics Data System (ADS)

    Hu, Shu; Gai, Baodong; Guo, Jingwei; Tan, Yannan; Liu, Jinbo; Li, Hui; Cai, Xianglong; Shi, Zhe; Liu, Wanfa; Jin, Yuqi; Sang, Fengting

    2015-02-01

    Sodium based excimer-pump alkali laser (Na-XPAL) is expected to be an efficient method to generate sodium beacon light, but the information about the spectroscopic characters of Na-XPAL remains sparse so far. In this work, we utilized the relative fluorescence intensity to study the absorption spectrum of blue satellites of complexes of sodium with different collision partners. The yellow fluorescence of Na D1 and D2 line was clearly visible. After processing the fluorescence intensity and the input pumping laser relative intensity, we obtained the Na-CH4 system's blue satellites was from 553nm to 556nm. Meanwhile, we experimentally demonstrated the Na-Ar and Na-Xe system's wavelength range of blue satellites. Also, it was observed that the Na-Xe system's absorption was stronger than the other two systems.

  9. Theoretical Study of the Absorption Spectrum and the Thermochemistry of the CF3OSO3 Radical

    NASA Astrophysics Data System (ADS)

    Cobos, Carlos J.; Croce, Adela E.

    2010-09-01

    The UV-visible absorption spectrum of the recently reported CF3OSO3 radical has been studied by using the time-dependent generalization of the density functional theory (TDDFT). For this a set of eleven hybrid functionals combined with the 6-311+G(3df) basis set were employed. The main features of the three experimental absorption bands of CF3OSO3 recorded over the 220 - 530 nm range are well reproduced by the calculations. A dissociation enthalpy for the CF3O-SO3 bond of 19.1 kcal mol-1 is predicted at the BAC-G3MP2//B3LYP/6-311+G(3df) level of theory

  10. Mg I absorption features in the solar spectrum near 9 and 12 microns

    NASA Technical Reports Server (NTRS)

    Glenar, David A.; Reuter, Dennis C.; Deming, Drake; Chang, Edward S.

    1988-01-01

    High-resolution FTS observations from the Kitt Peak National Solar Observatory and the Spacelab 3 ATMOS experiment have revealed additional infrared transitions due to Mg I in the spectra of both quiet sun and sunspot penumbra. In contrast to previous observations, these transitions are seen in absorption, not emission. Absorption intensities range from 1 to 7 percent of the continuum in the quiet sun. In the penumbra, the same features appear to show Zeeman splitting. Modeling of the line profiles in the photospheric spectrum shows evidence for a factor of three overabundance in the n = 5 or more levels of Mg I in the upper photosphere, but with no deviations from a Planck source function. It is concluded that whatever the process that produces the emission (including the Lemke and Holweger mechanism), it must occur well above the tau(5000) = 0.01 level.

  11. Investigations on the 1.7 micron residual absorption feature in the vegetation reflection spectrum

    NASA Technical Reports Server (NTRS)

    Verdebout, J.; Jacquemoud, S.; Andreoli, G.; Hosgood, B.; Sieber, A.

    1993-01-01

    The detection and interpretation of the weak absorption features associated with the biochemical components of vegetation is of great potential interest to a variety of applications ranging from classification to global change studies. This recent subject is also challenging because the spectral signature of the biochemicals is only detectable as a small distortion of the infrared spectrum which is mainly governed by water. Furthermore, the interpretation is complicated by complexity of the molecules (lignin, cellulose, starch, proteins) which contain a large number of different and common chemical bonds. In this paper, we present investigations on the absorption feature centered at 1.7 micron; these were conducted both on AVIRIS data and laboratory reflectance spectra of leaves.

  12. Effect of Sn on the optical band gap determined using absorption spectrum fitting method

    SciTech Connect

    Heera, Pawan; Kumar, Anup; Sharma, Raman

    2015-05-15

    We report the preparation and the optical studies on tellurium rich glasses thin films. The thin films of Se{sub 30}Te{sub 70-x} Sn{sub x} system for x= 0, 1.5, 2.5 and 4.5 glassy alloys prepared by melt quenching technique are deposited on the glass substrate using vacuum thermal evaporation technique. The analysis of absorption spectra in the spectral range 400nm–4000 nm at room temperature obtained from UV-VIS-NIR spectrophotometer [Perkin Elmer Lamda-750] helps us in the optical characterization of the thin films under study. The absorption spectrum fitting method is applied by using the Tauc’s model for estimating the optical band gap and the width of the band tail of the thin films. The optical band gap is calculated and is found to decrease with the Sn content.

  13. A family history study of schizophrenia spectrum disorders suggests new candidate genes in schizophrenia and autism.

    PubMed

    Goodman, A B

    1994-01-01

    To limit genetic heterogeneity, this study focused on the widely extended pedigrees of Ashkenazi Jewish schizophrenic and autistic probands, to determine if similar causal mechanisms might obtain for both conditions. At least two previous epidemiological studies have demonstrated increased risk for schizophrenia in Ashkenazi Jews. The hypothesis posed is that increased prevalence of various rare autosomal recessive diseases among the Ashkenazim might contribute to the increased vulnerability to schizophrenia and to autism in this large genetic isolate. Rates of amyotrophic lateral sclerosis (ALS) and bleeding disorders were significantly increased among relatives of schizophrenic and autistic probands, compared to relatives of normal probands. These results suggest new candidate loci in schizophrenia and autism, particularly the chromosome 15q23-24 locus of the hexosaminidase A gene, causing various GM2 gangliosidoses, and the 21q22.1-q22.2 loci of the antioxidant, superoxide dismutase gene, and a cytokine receptor gene. PMID:7831415

  14. The absorption spectrum of NH 2 in the region 5300 to 6800 Å

    NASA Astrophysics Data System (ADS)

    Ross, S. C.; Birss, F. W.; Vervloet, M.; Ramsay, D. A.

    1988-06-01

    The detailed analysis of the Ã2A 1- X˜2B 1 spectrum of NH 2 in the region 5300 to 6800 Å is reported. Term values derived from the analysis are also presented. Numerous new vibronic substates have been identified. The assignment of the substates and the perturbations detected are discussed in detail, making reference to the calculations of Jungen, Hallin, and Merer and also drawing on the argon matrix absorption spectrum of Robinson and McCarty. The parameters of a simplified model Hamiltonian are reported for most of the substates. The comparison of these results to the calculations of Jungen, Hallin, and Merer, along with the tendencies in the behavior of the spin-orbit coupling constant detected in their work, facilitated the assignments in the present work.

  15. Total Absorption Spectroscopy Study of (92)Rb Decay: A Major Contributor to Reactor Antineutrino Spectrum Shape.

    PubMed

    Zakari-Issoufou, A-A; Fallot, M; Porta, A; Algora, A; Tain, J L; Valencia, E; Rice, S; Bui, V M; Cormon, S; Estienne, M; Agramunt, J; Äystö, J; Bowry, M; Briz, J A; Caballero-Folch, R; Cano-Ott, D; Cucoanes, A; Elomaa, V-V; Eronen, T; Estévez, E; Farrelly, G F; Garcia, A R; Gelletly, W; Gomez-Hornillos, M B; Gorlychev, V; Hakala, J; Jokinen, A; Jordan, M D; Kankainen, A; Karvonen, P; Kolhinen, V S; Kondev, F G; Martinez, T; Mendoza, E; Molina, F; Moore, I; Perez-Cerdán, A B; Podolyák, Zs; Penttilä, H; Regan, P H; Reponen, M; Rissanen, J; Rubio, B; Shiba, T; Sonzogni, A A; Weber, C

    2015-09-01

    The antineutrino spectra measured in recent experiments at reactors are inconsistent with calculations based on the conversion of integral beta spectra recorded at the ILL reactor. (92)Rb makes the dominant contribution to the reactor antineutrino spectrum in the 5-8 MeV range but its decay properties are in question. We have studied (92)Rb decay with total absorption spectroscopy. Previously unobserved beta feeding was seen in the 4.5-5.5 region and the GS to GS feeding was found to be 87.5(25)%. The impact on the reactor antineutrino spectra calculated with the summation method is shown and discussed. PMID:26382674

  16. Absorption spectrum of the laser-populated 3D metastable levels in barium

    NASA Technical Reports Server (NTRS)

    Carlsten, J. L.; Mcilrath, T. J.; Parkinson, W. H.

    1975-01-01

    This paper deals with the details of the absorption spectrum of the 3D metastable term in barium. The 3D term was selectively populated with a tuneable dye laser. The fundamental triplet series (6s5d 3D-6snf 3F) is identified and extended out to n = 32. In addition, the absolute photoionization cross section was measured at 303 nm. The relative cross section from 303 to 250 nm was also measured with the absolute scale set by the measurement at 303 nm and was found to be nearly constant in the wavelength region measured.

  17. CFCl3 (CFC-11): UV absorption spectrum temperature dependence measurements and the impact on its atmospheric lifetime and uncertainty

    NASA Astrophysics Data System (ADS)

    McGillen, Max R.; Fleming, Eric L.; Jackman, Charles H.; Burkholder, James B.

    2013-09-01

    (CFC-11) is both an atmospheric ozone-depleting and potent greenhouse gas that is removed primarily via stratospheric UV photolysis. Uncertainty in the temperature dependence of its UV absorption spectrum is a significant contributing factor to the overall uncertainty in its global lifetime and, thus, model calculations of stratospheric ozone recovery and climate change. In this work, the CFC-11 UV absorption spectrum was measured over a range of wavelength (184.95-230 nm) and temperature (216-296 K). We report a spectrum temperature dependence that is less than that currently recommended for use in atmospheric models. The impact on its atmospheric lifetime was quantified using a 2-D model and the spectrum parameterization developed in this work. The calculated global annually averaged lifetime was 58.1 ± 0.7 years (2σ uncertainty due solely to the spectrum uncertainty). The lifetime is slightly reduced and the uncertainty significantly reduced from that obtained using current UV spectrum recommendations.

  18. CFCI3 (CFC-11): UV Absorption Spectrum Temperature Dependence Measurements and the Impact on Atmospheric Lifetime and Uncertainty

    NASA Technical Reports Server (NTRS)

    Mcgillen, Max R.; Fleming, Eric L.; Jackman, Charles H.; Burkholder, James B.

    2014-01-01

    CFCl3 (CFC-11) is both an atmospheric ozone-depleting and potent greenhouse gas that is removed primarily via stratospheric UV photolysis. Uncertainty in the temperature dependence of its UV absorption spectrum is a significant contributing factor to the overall uncertainty in its global lifetime and, thus, model calculations of stratospheric ozone recovery and climate change. In this work, the CFC-11 UV absorption spectrum was measured over a range of wavelength (184.95 - 230 nm) and temperature (216 - 296 K). We report a spectrum temperature dependence that is less than currently recommended for use in atmospheric models. The impact on its atmospheric lifetime was quantified using a 2-D model and the spectrum parameterization developed in this work. The obtained global annually averaged lifetime was 58.1 +- 0.7 years (2 sigma uncertainty due solely to the spectrum uncertainty). The lifetime is slightly reduced and the uncertainty significantly reduced from that obtained using current spectrum recommendations

  19. Dynamic registration of D216O absorption spectrum in silica aerogel

    NASA Astrophysics Data System (ADS)

    Sinitsa, L.; Lavrentieva, N.; Lugovskoi, A.

    2014-09-01

    Absorption spectra of the gas phase and adsorbed D2О in the silica aerogel with nanoscale pores were investigated in 3700-5400 cm-1 range using dynamic registration with Fourier Transform spectrometer IFS-125M. Two types of sample with pores of 60 nm wide - the nitrogen gas-treated and untreated aerogels - were examined. The surface treatment of the sample changes noticeably the broadband absorption of adsorbed water. Spectrum of D2O in the pores differs from the spectrum of bulk water as for bandwidth so for band maximum. It was found that treatment of the pores by dry nitrogen leads to increasing hydrophilic properties of the material and to change water band contour. The D2О line widths in both the aerogels exceed those of free monomer in 1.1-3 times at the same pressure. Calculations of self-broadening coefficients of the D2O lines were performed using semi-empirical method based on the impact theory of broadening and includes the correction factors. The calculated results well agree with experimental data. Greater differences were found for the shift of the line centre. The D2O line shifts in the treated pores significantly exceed line shifts in the untreated pores. For some lines, these shifts have the opposite sign indicating complex nature of the molecule-wall interaction.

  20. Invisible ink mark detection in the visible spectrum using absorption difference.

    PubMed

    Lee, Joong; Kong, Seong G; Kang, Tae-Yi; Kim, Byounghyun; Jeon, Oc-Yeub

    2014-03-01

    One of popular techniques in gambling fraud involves the use of invisible ink marks printed on the back surface of playing cards. Such covert patterns are transparent in the visible spectrum and therefore invisible to unaided human eyes. Invisible patterns can be made visible with ultraviolet (UV) illumination or a CCD camera installed with an infrared (IR) filter depending on the type of ink materials used. Cheating gamers often wear contact lenses or eyeglasses made of IR or UV filters to recognize the secret marks on the playing cards. This paper presents an image processing technique to reveal invisible ink patterns in the visible spectrum without the aid of special equipment such as UV lighting or IR filters. A printed invisible ink pattern leaves a thin coating on the surface with different refractive index for different wavelengths of light, which results in color dispersion or absorption difference. The proposed method finds the differences of color components caused by absorption difference to detect invisible ink patterns on the surface. Experiment results show that the proposed scheme is effective for both UV-active and IR-active invisible ink materials. PMID:24529777

  1. Efficient Algorithms for Estimating the Absorption Spectrum within Linear Response TDDFT

    SciTech Connect

    Brabec, Jiri; Lin, Lin; Shao, Meiyue; Govind, Niranjan; Yang, Chao; Saad, Yousef; Ng, Esmond

    2015-10-06

    We present two iterative algorithms for approximating the absorption spectrum of molecules within linear response of time-dependent density functional theory (TDDFT) framework. These methods do not attempt to compute eigenvalues or eigenvectors of the linear response matrix. They are designed to approximate the absorption spectrum as a function directly. They take advantage of the special structure of the linear response matrix. Neither method requires the linear response matrix to be constructed explicitly. They only require a procedure that performs the multiplication of the linear response matrix with a vector. These methods can also be easily modified to efficiently estimate the density of states (DOS) of the linear response matrix without computing the eigenvalues of this matrix. We show by computational experiments that the methods proposed in this paper can be much more efficient than methods that are based on the exact diagonalization of the linear response matrix. We show that they can also be more efficient than real-time TDDFT simulations. We compare the pros and cons of these methods in terms of their accuracy as well as their computational and storage cost.

  2. Absorption spectrum of the PbS-doped silica fibers fabricated by ALD and MCVD

    NASA Astrophysics Data System (ADS)

    Ye, Tang; Wen, Jianxiang; Dong, Yanhua; Wang, Tingyun

    2012-11-01

    The technique of atomic layer deposition (ALD) has been introduced to fabricate PbS-doped silica fibers, whose absorption peaks are discovered to be shifted from 1230 nm to 920 nm when the number of ALD deposition cycles varies from 80 to 30 during optical fiber preform fabrication. This is explained by suggesting that the PbS doped in fiber are under the 3D quantum confinement, i.e., quantum dots (QDs). An effective-mass approximat ion of the PbS QDs ' sizes is then made to show the shift of absorption peaks can be attributed to the change of size distribution of these dots.

  3. Revealing spectral features in two-photon absorption spectrum of Hoechst 33342: a combined experimental and quantum-chemical study.

    PubMed

    Olesiak-Banska, Joanna; Matczyszyn, Katarzyna; Zaleśny, Robert; Murugan, N Arul; Kongsted, Jacob; Ågren, Hans; Bartkowiak, Wojciech; Samoc, Marek

    2013-10-10

    We present the results of wide spectral range Z-scan measurements of the two-photon absorption (2PA) spectrum of the Hoechst 33342 dye. The strongest 2PA of the dye in aqueous solution is found at 575 nm, and the associated two-photon absorption cross section is 245 GM. A weak but clearly visible 2PA band at ∼850 nm is also observed, a feature that could not be anticipated from the one-photon absorption spectrum. On the basis of the results of hybrid quantum mechanics/molecular mechanics calculations, we put forward a notion that the long-wavelength feature observed in the two-photon absorption spectrum of Hoechst 33342 is due to the formation of dye aggregates. PMID:24016295

  4. Frequency-domain method for measuring spectral properties in multiple-scattering media: methemoglobin absorption spectrum in a tissuelike phantom

    NASA Astrophysics Data System (ADS)

    Fishkin, Joshua B.; So, Peter T. C.; Cerussi, Albert E.; Gratton, Enrico; Fantini, Sergio; Franceschini, Maria Angela

    1995-03-01

    We have measured the optical absorption and scattering coefficient spectra of a multiple-scattering medium (i.e., a biological tissue-simulating phantom comprising a lipid colloid) containing methemoglobin by using frequency-domain techniques. The methemoglobin absorption spectrum determined in the multiple-scattering medium is in excellent agreement with a corrected methemoglobin absorption spectrum obtained from a steady-state spectrophotometer measurement of the optical density of a minimally scattering medium. The determination of the corrected methemoglobin absorption spectrum takes into account the scattering from impurities in the methemoglobin solution containing no lipid colloid. Frequency-domain techniques allow for the separation of the absorbing from the scattering properties of multiple-scattering media, and these techniques thus provide an absolute

  5. Molecular level all-optical logic with chlorophyll absorption spectrum and polarization sensitivity

    NASA Astrophysics Data System (ADS)

    Raychaudhuri, B.; Bhattacharyya (Bhaumik), S.

    2008-06-01

    Chlorophyll is suggested as a suitable medium for realizing optical Boolean logic at the molecular level in view of its wavelength-selective property and polarization sensitivity in the visible region. Spectrophotometric studies are made with solutions of total chlorophyll and chromatographically isolated components, viz. chlorophyll a and b and carotenoids extracted from pumpkin leaves of different maturity stages. The absorption features of matured chlorophyll with two characteristic absorption peaks and one transmission band are molecular properties and independent of concentration. A qualitative explanation of such an absorption property is presented in terms of a ‘particle in a box’ model and the property is employed to simulate two-input optical logic operations. If both of the inputs are either red or blue, absorption is high. If either one is absent and replaced by a wavelength of the transmission band, e.g. green, absorption is low. Assigning these values as 0 s or 1 s, AND and OR operations can be performed. A NOT operation can be simulated with the transmittance instead of the absorbance. Also, the shift in absorbance values for two different polarizations of the same monochromatic light can simulate two logical states with a single wavelength. Cyclic change in absorbance is noted over a rotation of 360° for both red and blue peaks, although the difference is not very large. Red monochromatic light with polarizations apart by 90°, corresponding to maximum and minimum absorption, respectively, may be assigned as the two logical states. The fluorescence emissions for different pigment components are measured at different excitation wavelengths and the effect of fluorescence on the red absorbance is concluded to be negligible.

  6. The Electronic Absorption Spectrum of Molecular Iodine: A New Fitting Procedure for the Physical Chemistry Laboratory

    NASA Astrophysics Data System (ADS)

    Pursell, Christopher J.; Doezema, Lambert

    1999-06-01

    This paper presents a different approach to the data treatment for the electronic absorption spectrum of molecular iodine, a standard experiment in the undergraduate physical chemistry laboratory. Traditionally, students analyze the transitions originating from the u'' = 0 level using a Birge-Sponer plot and thereby determine the various molecular constants and energies. Our treatment involves simply fitting the transition frequencies to a second-order polynomial. This fit then yields a direct determination of the important molecular constants along with the various energy terms. With the availability of common graphing programs such as Excel, Kaleidagraph, and SigmaPlot, students can take advantage of more advanced fitting techniques and no longer have to rely on simple linear plots. Additionally, students find this new approach more satisfying and we believe it has pedagogical advantages over the Birge-Sponer treatment.

  7. Theoretical reproduction of the Q-band absorption spectrum of free-base chlorin

    NASA Astrophysics Data System (ADS)

    Wójcik, Justyna; Ratuszna, Alicja; Peszke, Jerzy; Wrzalik, Roman

    2015-01-01

    The computational results of the features observed in the room-temperature Q-band absorption spectrum of free-base chlorin (H2Ch) are presented. The vibrational structures of the first and second excited singlet states were calculated based on a harmonic approximation using density functional theory and its time dependent extension within the Franck-Condon and Herzberg-Teller approaches. The outcome allowed to identify the experimental bands and to assign them to the specific vibrational transitions. A very good agreement between the simulated and measured wavelengths and their relative intensities provided the opportunity to predict the origin of the S0 → S2 transition which could not be determined experimentally.

  8. Theoretical reproduction of the Q-band absorption spectrum of free-base chlorin.

    PubMed

    Wójcik, Justyna; Ratuszna, Alicja; Peszke, Jerzy; Wrzalik, Roman

    2015-01-21

    The computational results of the features observed in the room-temperature Q-band absorption spectrum of free-base chlorin (H2Ch) are presented. The vibrational structures of the first and second excited singlet states were calculated based on a harmonic approximation using density functional theory and its time dependent extension within the Franck-Condon and Herzberg-Teller approaches. The outcome allowed to identify the experimental bands and to assign them to the specific vibrational transitions. A very good agreement between the simulated and measured wavelengths and their relative intensities provided the opportunity to predict the origin of the S0 → S2 transition which could not be determined experimentally. PMID:25612704

  9. The UV-vis absorption spectrum of the flavonol quercetin in methanolic solution: A theoretical investigation

    NASA Astrophysics Data System (ADS)

    Andrade-Filho, T.; Ribeiro, T. C. S.; Del Nero, J.

    2009-07-01

    The UV-vis absorption spectrum of the solvated quercetin molecule in methanol was investigated theoretically by means of an elegant type of QM/MM scheme better known as sequential Monte Carlo/quantum mechanics (S-MC/QM) methodology. A set of 125 uncorrelated Monte Carlo molecular liquid structures were properly selected through the autocorrelation function of the energy in order to be used in the quantum mechanical calculations. These molecular liquid structures were obtained by means of the radial and minimum distance distribution functions. A detailed account of the pattern of hydrogen bond structures obtained in this study is also available. The computed results obtained here were directly compared with the available experimental data in order to validate our theoretical model and through this comparison a very good conformity between theoretical and available experimental results was found.

  10. Analysis of ultraviolet absorption spectrum of Chinese herbal medicine-Cortex Fraxini by double ANN

    NASA Astrophysics Data System (ADS)

    Bai, Lifei; Zhang, Haitao; Wang, Hongxia; Li, Junfeng; Lu, Lei; Zhang, Hanqi; Wang, Hongyan

    2006-11-01

    A fast, accurate and convenient method for the simultaneous determination of multi-component in the Chinese herbal medicine was proposed by using ultraviolet absorption spectrum. In this method, dummy components were added to training sample, and a double artificial neural network (DANN) that has the function of high self-revision and self-simulation was used. Effect of other interference components could be eliminated by adjusting concentration of dummy components. Therefore, the accuracy of concentration prediction for multi-component in the complicated Chinese herbal medicine was improved. It has been realized that two effective components of Cortex Fraxini, aesculin and aesculetin, were simultaneously determined, without any separation. The predicted accuracy was 92% within the permitted relative errors. The measurement precisions of the aesculin and aesculetin were 0.37% and 1.5%, respectively.

  11. The soft X-ray absorption spectrum of the allyl free radical.

    PubMed

    Alagia, M; Bodo, E; Decleva, P; Falcinelli, S; Ponzi, A; Richter, R; Stranges, S

    2013-01-28

    The first experimental study of the X-ray absorption spectrum (XAS) of the allyl free radical, CH(2)CHCH(2), is reported. A supersonic He seeded beam of hyperthermal allyl radicals was crossed by a high resolution synchrotron radiation (SR) in the focus of a 3D ion momentum imaging time-of-flight (TOF) spectrometer to investigate the soft X-ray absorption and fragmentation processes. The XAS, recorded as Total-Ion-Yield (TIY), is dominated by C1s electron excitations from either the central carbon atom, C(C), or the two terminal carbon atoms, C(T), to the frontier orbitals, the semi-occupied-molecular-orbital (SOMO) and the lowest-unoccupied-molecular-orbital (LUMO). All of the intense features in the XAS could only be assigned with the aid of ab initio spectral simulation at the Multi-Configuration Self-Consistent-Field (MCSCF) level of theory, this level being required because of the multi-reference nature of the core-excited state wavefunctions of the open shell molecule. The ionization energies (IEs) of the singlet and triplet states of the C1s ionized allyl radical (XPS) were also calculated at the MCSCF level. PMID:23232557

  12. Tight binding model of conformational disorder effects on the optical absorption spectrum of polythiophenes.

    PubMed

    Bombile, Joel H; Janik, Michael J; Milner, Scott T

    2016-05-14

    Semiconducting polymers are soft materials with many conformational degrees of freedom. The limited understanding of how conformational disorder affects their optoelectronic properties is a key source of difficulties that limits their widespread usage in electronic devices. We develop a coarse-grained approach based on the tight binding approximation to model the electronic degrees of freedom of polythiophene chains, taking into account conformational degrees of freedom. Particularly important is dihedral disorder, which disrupts extended electronic states. Our tight binding model is parameterized using density functional theory (DFT) calculations of the one-dimensional band structures for chains with imposed periodic variations in dihedral angles. The model predicts valence and conduction bands for these chain conformations that compare well to DFT results. As an initial application of our model, we compute the optical absorption spectrum of poly(3-hexylthiophene) chains in solution. We observe a broadening of the absorption edge resulting from dihedral disorder, just shy of the experimental broadening. We conclude that the effects of molecular disorder on the optoelectronic properties of conjugated polymer single chains can be mostly accounted for by torsional disorder alone. PMID:27087455

  13. Analysis of urinary stone based on a spectrum absorption FTIR-ATR

    NASA Astrophysics Data System (ADS)

    Asyana, V.; Haryanto, F.; Fitri, L. A.; Ridwan, T.; Anwary, F.; Soekersi, H.

    2016-03-01

    This research analysed the urinary stone by measuring samples using Fourier transform infrared-attenuated total reflection spectroscopy and black box analysis. The main objective of this study is to find kinds of urinary stone and determine a total spectrum, which is a simple model of the chemical and mineral composition urinary stone through black box analysis using convolution method. The measurements result showed that kinds of urinary stone were pure calcium oxalate monohydrate, ion amino acid calcium oxalate monohydrate, a mixture of calcium oxalate monohydrate with calcium phosphate, a mixture of ion amino acid calcium oxalate monohydrate and calcium phosphate,pure uric acid, ion amino acid uric acid, and a mixture of calcium oxalate monohydrate with ion amino acid uric acid. The results of analysis of black box showed characteristics as the most accurate and precise to confirm the type of urinary stones based on theregion absorption peak on a graph, the results of the convolution, and the shape of the total spectrum on each urinary stones.

  14. Signature OH Absorption Spectrum from cluster Models of Solvation: a solvent-to-solute charge transfer state

    SciTech Connect

    Tsai, Ming Kang; Kowalski, Karol; Valiev, Marat; Dupuis, Michel

    2007-10-25

    ab initio electronic structure theories applied to cluster models support the characterization of the signature of the OH absorption spectrum to be a solvent-to-solute charge transfer state affected by the hydrogen bonding environment in the region of 250 nm (calculated). The vertical excited states were calculated at the TDDFT level of theory with using OH(H2O)n clusters (n = 0-7, 16) with companion calculations at the EOM-CCSD level of theory for n ≤ 7. An intense solvent-to-solute charge transfer transition was calculated for n = 16 cluster where the donor and acceptor molecular orbitals are in favorable alignment. In the other smaller clusters the transitions in this region were found to be weak. The present findings are consistent with the experimental absorption at 230 nm suggested to be a solvent-to-solute charge transfer and provide insight into the electronic states and orbitals that give rise to the intensity of the band. This work was supported by the U.S. Department of Energy's (DOE) Office of Basic Energy Sciences, Chemical Sciences program, and was performed in part using the Molecular Science Computing Facility (MSCF) in the William R. Wiley Environmental Molecular Sciences Laboratory, a DOE national scientific user facility located at the Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for DOE.

  15. High-resolution, vacuum-ultraviolet absorption spectrum of boron trifluoride

    SciTech Connect

    Hughes, Patrick P.; Thompson, Alan K.; Vest, Robert E.; Sprague, Matthew K.; Irikura, Karl K.; Beasten, Amy; McComb, Jacob C.; Al-Sheikhly, Mohamad; Coplan, Michael A.; Clark, Charles W.

    2014-11-21

    In the course of investigations of thermal neutron detection based on mixtures of {sup 10}BF{sub 3} with other gases, knowledge was required of the photoabsorption cross sections of {sup 10}BF{sub 3} for wavelengths between 135 and 205 nm. Large discrepancies in the values reported in existing literature led to the absolute measurements reported in this communication. The measurements were made at the SURF III Synchrotron Ultraviolet Radiation Facility at the National Institute of Standards and Technology. The measured absorption cross sections vary from 10{sup −20} cm{sup 2} at 135 nm to less than 10{sup −21} cm{sup 2} in the region from 165 to 205 nm. Three previously unreported absorption features with resolvable structure were found in the regions 135–145 nm, 150–165 nm, and 190–205 nm. Quantum mechanical calculations, using the TD-B3LYP/aug-cc-pVDZ variant of time-dependent density functional theory implemented in Gaussian 09, suggest that the observed absorption features arise from symmetry-changing adiabatic transitions.

  16. The integrated radio continuum spectrum of M33 - Evidence for free-free absorption by cool ionized gas

    NASA Technical Reports Server (NTRS)

    Israel, F. P.; Mahoney, M. J.; Howarth, N.

    1992-01-01

    We present measurements of the integrated radio continuum flux density of M33 at frequencies between 22 and 610 MHz and discuss the radio continuum spectrum of M33 between 22 MHz and 10 GHz. This spectrum has a turnover between 500 and 900 MHz, depending on the steepness of the high frequency radio spectrum of M33. Below 500 MHz the spectrum is relatively flat. We discuss possible mechanisms to explain this spectral shape and consider efficient free-free absorption of nonthermal emission by a cool (not greater than 1000 K) ionized gas to be a very likely possibility. The surface filling factor of both the nonthermal and the thermal material appears to be small (of order 0.001), which could be explained by magnetic field/density fluctuations in the M 33 interstellar medium. We briefly speculate on the possible presence of a nuclear radio source with a steep spectrum.

  17. The ultraviolet absorption spectrum of the quasar PKS 0405-12 and the local density of Lyman-alpha absorption systems

    NASA Technical Reports Server (NTRS)

    Bahcall, John N.; Jannuzi, Buell T.; Schneider, Donald P.; Hartig, George F.

    1993-01-01

    A sample of 32 absorption lines has been identified in the ultraviolet spectrum of the z = 0.57 quasar PKS 0405-12. Data cover the wavelength range 1190-3260 A. There are 10 extragalactic Ly-alpha absorption lines in the complete sample, all with observed equivalent widths greater than or equal to 0.40 A; three of the Ly-alpha lines have Ly-beta counterparts. The number of Ly-alpha lines observed in the spectrum of PKS 0405-12 is within 1 sigma of the number predicted on the basis of previous HST observations of 3C 273 and of H1821 + 643. Combining the HST observations of 3C 273, H1821 + 643, and PKS 0405-12, we estimate the local number density of Ly-alpha systems with rest equivalent widths larger than 0.32 A to be about 15 +/- 4 Ly-alpha lines per unit redshift. Ground-based images reveal a rich field of galaxies in the direction of PKS 0405-12, including many galaxies with the brightnesses and sizes expected if they belong to a cluster associated with the quasar. The quasar spectrum does not show any evidence for absorption at the redshift of the emission lines, indicating a covering factor of less than unity for the halos of galaxies in the cluster around PKS 0405 - 12.

  18. Temperature sounding from the absorption spectrum of CO2 at 4.3 microns. [in stratosphere and lower mesosphere

    NASA Technical Reports Server (NTRS)

    Toth, R. A.

    1977-01-01

    A new method is described for obtaining the temperature profile in the stratosphere and lower mesosphere from observations of the absorption spectrum of the high J lines of carbon dioxide at 4.3 microns. This concept is based upon the measurement of the integrated absorption of individual CO2 lines whose strengths depend strongly on temperature and that the absorption of these lines are obtained from measurements of the solar or stellar spectrum through an atmospheric path. The technique involves a rapidly converging iterative process in which the equivalent widths of the individual vibration-rotation lines of CO2 are used. Theoretical calculations are presented for balloon and satellite observations using a model atmosphere. Experimental results are given from spectra obtained with a balloon-borne Fourier interferometer spectrometer in which the sun was observed at low zenith angles. The experimental results are compared to rocketsonde data.

  19. Development of nanostructured luminophor coating for broadening of solar cell absorption spectrum

    NASA Astrophysics Data System (ADS)

    Kryuchyn, A. A.; Beliak, Ie. V.

    2014-10-01

    One of the major concerns in the area of high efficient solar cell production is a substantial shift between the solar radiation spectra and optical absorption spectra of a photoelectric transducer that significantly reduces solar cell efficiency. We propose a concept which based on coating of conventional and cheap photoelectric transducer with a luminophor that transmits longer wavelengths of the sunlight, absorbs shorter wavelengths and converts them into longer ones by the value of the Stocks shift. While photoluminescent light is not collimated and thus losses may reach up to 50% of converted light, it was also proposed to make micropattern formation at photoelectric transducer surface. We propose synthesizing of specific materials based on composite pyrazoline dyes with addition of polymethylmethacrylate, polystyrene and UV-laquers. It was revealed that synthesized luminophor coating are characterized by sufficiently enough Stocks shift (200-400 nm), high quantum yield (near 80%) and stability under circumstances of long term radiation. Further research demonstrated potential of the significant characteristic's improvement by introducing of organic dye molecules in the white zeolite matrix with additional laser annealing at low intensity. Experimental results have shown that photoluminescent spectrum of pyrazoline dye didn't change shape, bandwidth and amplitude for last 10 years. It was decided that obtained stability is being caused by porous matrix of white zeolite. Simulation of the solar cell functioning helped to understand physics of the process and simplify problem of microrelief and luminophor optimal parameters search.

  20. A variable absorption feature in the X-ray spectrum of a magnetar.

    PubMed

    Tiengo, Andrea; Esposito, Paolo; Mereghetti, Sandro; Turolla, Roberto; Nobili, Luciano; Gastaldello, Fabio; Götz, Diego; Israel, Gian Luca; Rea, Nanda; Stella, Luigi; Zane, Silvia; Bignami, Giovanni F

    2013-08-15

    Soft-γ-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slowly rotating, isolated neutron stars that sporadically undergo episodes of long-term flux enhancement (outbursts) generally accompanied by the emission of short bursts of hard X-rays. This behaviour can be understood in the magnetar model, according to which these sources are mainly powered by their own magnetic energy. This is supported by the fact that the magnetic fields inferred from several observed properties of SGRs and AXPs are greater than-or at the high end of the range of-those of radio pulsars. In the peculiar case of SGR 0418+5729, a weak dipole magnetic moment is derived from its timing parameters, whereas a strong field has been proposed to reside in the stellar interior and in multipole components on the surface. Here we show that the X-ray spectrum of SGR 0418+5729 has an absorption line, the properties of which depend strongly on the star's rotational phase. This line is interpreted as a proton cyclotron feature and its energy implies a magnetic field ranging from 2 × 10(14) gauss to more than 10(15) gauss. PMID:23955229

  1. Absorption spectrum and ultrafast response of monolayer and bilayer transition-metal dichalcogenides

    NASA Astrophysics Data System (ADS)

    Turkowski, Volodymyr; Ramirez-Torres, Alfredo; Rahman, Talat S.

    2015-03-01

    We apply a combined time-dependent density functional theory and many-body theory approach to examine the absorption spectrum and nonequilibrium response of monolayer and bilayer MoS2, MoSe2, WS2 and WSe2 systems. In particular, we evaluate the possibility of existence of bound states - excitons and trions in the undoped systems. In a previous work we have already demonstrated that the binding energies of these states in the monolayer systems are large which makes them available for room temperature applications. We analyze the possibility of ultrafast electron-hole separation in bilayer systems through inter-layer hole transfer, and show that such a possibility exists, in agreement with experimental observations. For doped systems we consider the possibility of Mahan excitonic states in monolayers and show that the binding energy for these states is of the order of 10 meV. We perform a detailed analysis of the relaxation of doped monolayers excited by ultrafast laser pulse by taking into account electron-phonon scattering effects, and demonstrate that ultrafast (10-100fs) processes, including luminescence, may be relevant for these materials. Work supported in part by DOE Grant No. DOE-DE-FG02-07ER46354.

  2. CFCl3 (CFC-11): UV Absorption Spectrum Temperature Dependence Measurements and the Impact on Atmospheric Lifetime Uncertainty

    NASA Astrophysics Data System (ADS)

    McGillen, M.; Fleming, E. L.; Jackman, C. H.; Burkholder, J. B.

    2013-12-01

    CFCl3 (CFC-11) is both a major ozone-depleting substance and a potent greenhouse gas that is removed primarily via stratospheric UV photolysis. Uncertainty in the temperature dependence of its UV absorption spectrum is a significant contributing factor to the overall uncertainty in its global lifetime and, thus, model calculations of stratospheric ozone recovery and climate change. In this work, the CFC-11 UV absorption spectrum was measured over a range of wavelength (184.95-230 nm) and temperature (216-296 K). We report a spectrum temperature dependence that is less than currently recommended for use in atmospheric models. The impact on its atmospheric lifetime was quantified using the NASA Goddard Space Flight Center 2-D coupled chemistry-radiation-dynamics model and the spectrum parameterization developed in this work. The modeled global annually averaged lifetime was 58.1 × 0.7 years (2σ uncertainty due solely to the spectrum uncertainty). The lifetime is slightly reduced and the uncertainty significantly reduced from that obtained using current UV spectrum recommendations. CFCl 3 (CFC-11) 2-D model results: Left: Global annually averaged loss rate coefficient (local lifetime) and photolysis and reaction contributions (see legend). Middle: Molecular loss rate and uncertainty limits; the slow and fast profiles were calculated using the 2σ uncertainty estimates in the CFC-11 UV absorption spectrum from this work. Right: CFC-11 concentration profile. CFC-11 loss process contribution to the overall local lifetime uncertainty (2σ) calculated using the 2-D model (see text). Left: Results obtained from this work. Right: Results obtained using model input from Sander et al. [2011] and updates in SPARC [2013].

  3. The Hubble Space Telescope Quasar Absorption Line Key Project: The Unusual Absorption-Line System in the Spectrum of PG 2302+029--Ejected or Intervening?

    NASA Technical Reports Server (NTRS)

    Jannuzi, B. T.; Hartig, G. F.; Kirhakos, S.; Sargent, W. L. W.; Turnshek, D. A.; Weymann, R. J.; Bahcall, J. N.; Bergeron, J.; Boksenberg, A.; Savage, B. D.; Schneider, D. P.; Wolfe, A. M.

    1996-01-01

    We report the discovery of a high-ionization broad absorption line system at a redshift of z(sub abs) = 0.695 in the spectrum of the z(sub em) = 1.052 radio-quiet quasar PG 2302+029. Broad absorption with FWHM from 3000 to 5000 km/s is detected from C iv, N v, and O vi in Hubble Space Telescope (HST) Faint Object Spectrograph spectra of the quasar. A narrow-line system (FWHM approx. 250 km/s) at z(sub abs) = 0.7016 is resolved from the broad blend and includes absorption by Ly alpha and the C iv, N v, and O vi doublets. No absorption by low-ionization metal species (e.g., Si II and Mg II) is detected in the HST or ground-based spectra for either the broad or the narrow system. The centroids of the broad system lines are displaced by approx. 56,000 km/s to the blue of the quasar's broad emission lines. The reddest extent of the broad-line absorption is more than 50,000 km/s from the quasar. The properties of this system are unprecedented, whether it is an intervening or an ejected system.

  4. On the Putative Detection of Z>0 X-Ray Absorption Features in the Spectrum of Mrk 421

    SciTech Connect

    Rasmussen, Andrew P.; Kahn, Steven M.; Paerels, Frits; Herder, Jan Willem den; Kaastra, Jelle; de Vries, Cor; /SRON, Utrecht

    2006-04-28

    In a series of papers, Nicastro et al. have claimed the detection of z > 0 O VII absorption features in the spectrum of Mrk 421 obtained with the Chandra Low Energy Transmission Grating Spectrometer (LETGS). We evaluate those claims in the context of a high quality spectrum of the same source obtained with the Reflection Grating Spectrometer (RGS) on XMM-Newton. The data comprise over 955 ksec of usable exposure time and more than 2.6 x 10{sup 4} counts per 50 m{angstrom} at 21.6 {angstrom}. We concentrate on the spectrally clean region (21.3 < {lambda} < 22.5 {angstrom}) where sharp features due to the astrophysically abundant O VII may reveal an intervening, warm-hot intergalactic medium (WHIM). In spite of the fact that the sensitivity of the RGS data is higher than that of the original LETGS data presented by Nicastro et al., we do not confirm detection of any of the intervening systems claimed to date. Rather, we detect only three unsurprising, astrophysically expected features down to the log (N{sub i}) {approx} 14.6 (3{sigma}) sensitivity level. Each of the two purported WHIM features is rejected with a statistical confidence that exceeds that reported for its initial detection. While we can not rule out the existence of fainter, WHIM related features in these spectra, we suggest that previous discovery claims were premature. A more recent paper by Williams et al. claims to have demonstrated that the RGS data we analyze here do not have the resolution or statistical quality required to confirm or deny the LETGS detections. We show that the Williams et al. reduction of the RGS data was highly flawed, leading to an artificial and spurious degradation of the instrument response. We carefully highlight the differences between our analysis presented here and those published by Williams et al.

  5. Vibronic and Rydberg series assignments in the vacuum ultraviolet absorption spectrum of nitrous oxide

    NASA Astrophysics Data System (ADS)

    Shastri, Aparna; Singh, Param Jeet; Krishnakumar, Sunanda; Mandal, Anuvab; Raja Sekhar, B. N.; D'Souza, R.; Jagatap, B. N.

    2014-11-01

    We report a comprehensive photoabsorption study of nitrous oxide (N2O) in the vacuum ultraviolet (45,000-95,000 cm-1) region using synchrotron radiation. The observed spectrum comprises of a few valence transitions and low lying Rydberg series converging to the two spin-orbit components (2П1/2,3/2) of the ground state of N2O+. Spectral analysis is aided by extensive quantum chemical calculations of vertical excited states, oscillator strengths and potential energy curves using the time dependent density functional theory. Vibronic bands observed in the first absorption system (45,000-60,000 cm-1) are assigned to hot band progressions in υ2‧ originating from v″=1 or 2. New insights into the assignment of the well-formed progression of bands in the X1Σ+→C1П system (60,000-72,000 cm-1) are afforded by consideration of the Renner-Teller interaction. A set of molecular vibrational parameters (ω2=467 cm-1, x22=-2.9, ε=-0.24) for the C1П state are derived from a fitting of the experimental data. The 3pπ1Σ+ state at ~77,600 cm-1 shows a large quantum defect (0.96) which is explained as arising due to mixed valence-Rydberg character. In the 85,000-95,000 cm-1 region, a number of absorption features are observed with greater clarity than in earlier photoabsorption studies and assigned to Rydberg series of type nlλ (n=3,4; l=s,p,d; λ=σ,π,δ) and accompanying vibronic bands. This work has resulted in clarification of several discrepancies in earlier Rydberg series assignments. Additionally, the 3pπ 3Σ- Rydberg state at 85,788 cm-1, the valence transition 7σ→3π (1П) at 87,433 cm-1 and the 3dλ Rydberg series in the 91,700-92,600 cm-1 region are assigned for the first time.

  6. Interpretation of the optical absorption spectrum of Co3O4 with normal spinel structure from first principles calculations

    NASA Astrophysics Data System (ADS)

    Lima, A. F.

    2014-01-01

    First principles calculations based on density functional theory have been employed to study the electronic, magnetic and optical properties of Co3O4 in a cubic normal spinel structure. Exchange and correlation effects between electrons were treated by a B3PW91 hybrid functional, which produced better results than others scheme, such as GGA+U or PBE0 hybrid functionals or mBJ semilocal potential. The work focuses on clarifying the nature of the optical absorption bands, which have motivated various theoretical and experimental works in the literature. The calculated optical absorption spectrum was compared with available experimental data. On the basis of this calculated electronic and magnetic structure, the optical absorption peaks (theoretical and experimental) could be satisfactorily explained in terms of d3d charge transfer transitions between both CO2+→CO2+ and CO3+→CO3+ ions. The calculations also predicted that the crystal field splittings at both octahedral and tetrahedral sites in the Co3O4 compound are of the same magnitude. First principles calculations were used to predict optical properties of Co3O4. Exchange-correlation electronic effects were treated by a B3PW91 hybrid functional. Calculated optical absorption spectrum was compared with experimental data. Optical absorption peaks could be satisfactorily explained.

  7. Failure of Energy Transfer between Identical Aromatic Molecules on Excitation at the Long Wave Edge of the Absorption Spectrum

    PubMed Central

    Weber, Gregorio; Shinitzky, Meir

    1970-01-01

    Electronic energy transfer among identical molecules has been followed by the depolarization of the fluorescence in concentrated solutions as well as in dimers, polymers, and micelle systems. In the many aromatic fluorophores examined, unlike a few nonaromatic ones, transfer is much decreased or altogether undetectable on excitation at the red edge of the absorption spectrum. The phenomenon is not due to the transfer taking place during a small fraction of the total fluorescence lifetime, nor is it explainable by a decrease in overlap of absorption and emission upon edge excitation. PMID:16591825

  8. Communication: Does a single CH3CN molecule attached to Ru(bipy)3(2+) affect its absorption spectrum?

    PubMed

    Stockett, M H; Brøndsted Nielsen, S

    2015-05-01

    Tris(bipyridine)ruthenium(II) (Ru(bipy)3 (2+)) is a prototypical transition metal coordination complex whose photophysical properties have attracted considerable attention. A much debated issue is whether the metal-to-ligand charge transfer (MLCT) transition that accounts for the complex's beautiful red color is fully delocalized across all three bipyridine ligands or located on just one ligand. Here, we show based on gas-phase action spectroscopy that attachment of a single acetonitrile molecule does not change the absorption spectrum from that of the bare ions, which is indicative of a delocalized state. However, the gas-phase spectra of the bare and one solvent molecule complexes are significantly blueshifted relative to that obtained in bulk acetonitrile, which suggests that in solution the polarizability of many solvent molecules working together can localize the MLCT state. Our data clearly show that more than one solvent molecule is needed to break the symmetry of the MLCT excited state and reproduce its solution-phase characteristics. PMID:25956080

  9. Communication: Does a single CH3CN molecule attached to Ru(bipy)32+ affect its absorption spectrum?

    NASA Astrophysics Data System (ADS)

    Stockett, M. H.; Brøndsted Nielsen, S.

    2015-05-01

    Tris(bipyridine)ruthenium(II) (Ru(bipy)32+) is a prototypical transition metal coordination complex whose photophysical properties have attracted considerable attention. A much debated issue is whether the metal-to-ligand charge transfer (MLCT) transition that accounts for the complex's beautiful red color is fully delocalized across all three bipyridine ligands or located on just one ligand. Here, we show based on gas-phase action spectroscopy that attachment of a single acetonitrile molecule does not change the absorption spectrum from that of the bare ions, which is indicative of a delocalized state. However, the gas-phase spectra of the bare and one solvent molecule complexes are significantly blueshifted relative to that obtained in bulk acetonitrile, which suggests that in solution the polarizability of many solvent molecules working together can localize the MLCT state. Our data clearly show that more than one solvent molecule is needed to break the symmetry of the MLCT excited state and reproduce its solution-phase characteristics.

  10. Trifluoro methyl peroxynitrate (CF 3OONO 2): Temperature dependence of the UV absorption spectrum and atmospheric implications

    NASA Astrophysics Data System (ADS)

    Malanca, Fabio E.; Chiappero, Malisa S.; Argüello, Gustavo A.; Wallington, Timothy J.

    The ultraviolet absorption spectrum of gas phase CF 3OONO 2 has been measured over the wavelength range 200-340 nm at 233-300 K. Absorption cross-sections at wavelengths of 290-340 nm were found to increase significantly with increasing temperature. The UV spectra of CF 3C(O)Cl and CF 3C(O)F were measured and were consistent with previous work [Rattigan et al., 1993. Temperature-dependent absorption cross-sections of CF 3COCl, CF 3COF, CH 3COF, CCl 3CHO and CF 3COOH. Journal of Photochemistry and Photobiology A: Chemistry 73, 1-9]. Implications for the atmospheric chemistry of CF 3OONO 2 are discussed.

  11. Ultraviolet (250-550  nm) absorption spectrum of pure water.

    PubMed

    Mason, John D; Cone, Michael T; Fry, Edward S

    2016-09-01

    Data for the spectral light absorption of pure water from 250 to 550 nm have been obtained using an integrating cavity made from a newly developed diffuse reflector with a very high UV reflectivity. The data provide the first scattering-independent measurements of absorption coefficients in the spectral gap between well-established literature values for the absorption coefficients in the visible (>400  nm) and UV (<200  nm). A minimum in the absorption coefficient has been observed in the UV at 344 nm; the value is 0.000811±0.000227  m-1. PMID:27607297

  12. The origin of blueshifted absorption features in the X-ray spectrum of PG 1211+143: outflow or disc

    NASA Astrophysics Data System (ADS)

    Gallo, L. C.; Fabian, A. C.

    2013-07-01

    In some radio-quiet active galactic nuclei (AGN), high-energy absorption features in the X-ray spectra have been interpreted as ultrafast outflows (UFOs) - highly ionized material (e.g. Fe XXV and Fe XXVI) ejected at mildly relativistic velocities. In some cases, these outflows can carry energy in excess of the binding energy of the host galaxy. Needless to say, these features demand our attention as they are strong signatures of AGN feedback and will influence galaxy evolution. For the same reason, alternative models need to be discussed and refuted or confirmed. Gallo and Fabian proposed that some of these features could arise from resonance absorption of the reflected spectrum in a layer of ionized material located above and corotating with the accretion disc. Therefore, the absorbing medium would be subjected to similar blurring effects as seen in the disc. A priori, the existence of such plasma above the disc is as plausible as a fast wind. In this work, we highlight the ambiguity by demonstrating that the absorption model can describe the ˜7.6 keV absorption feature (and possibly other features) in the quasar PG 1211+143, an AGN that is often described as a classic example of a UFO. In this model, the 2-10 keV spectrum would be largely reflection dominated (as opposed to power law dominated in the wind models) and the resonance absorption would be originating in a layer between about 6 and 60 gravitational radii. The studies of such features constitute a cornerstone for future X-ray observatories like Astro-H and Athena+. Should our model prove correct, or at least important in some cases, then absorption will provide another diagnostic tool with which to probe the inner accretion flow with future missions.

  13. Matrix-Isolated Infrared Absorption Spectrum of CH2IOO Radical.

    PubMed

    Zhang, Xu; Sander, Stanley P; Cheng, Lan; Thimmakondu, Venkatesan S; Stanton, John F

    2016-01-21

    The peroxyiodomethyl radical, CH2IOO, was generated in cryogenic matrices using tandem supersonic nozzles. One hyperthermal nozzle decomposes diiodomethane (CH2I2) to generate intense beams of CH2I radicals, while the second nozzle continuously deposits O2/argon (Ar) on the matrix at 10 K. The CH2I and O2 in the Ar matrix react to produce the target peroxy radical (CH2IOO). The absorption spectra of the products are monitored with a Fourier transform infrared spectrometer. Eight of the 12 fundamental infrared bands for CH2IOO were observed in an argon matrix at 5 K. The experimental frequencies (cm(-1)) are ν3 = 1407.3, ν4 = 1230.4, ν5 = 1223.2, ν6 = 1085.3, ν7 = 919.9, ν8 = 839.9, ν9 = 567.5, and ν10 = 496.2. Additional confirmation for the vibrational assignment comes from a study of the CH2I(18)O(18)O isotopic species. The six observed frequencies (cm(-1)) for CH2I(18)O(18)O are ν3 = 1407.8, ν4 = 1228.0, ν6 = 1030.8, ν7 = 899.6, ν8 = 836.0, and ν10 = 494.6. Unlike CH2I(16)O(16)O, the ν5 and ν9 bands were not observed for CH2I(18)O(18)O. To guide the experimental analysis, ab initio calculations of the infrared spectrum based on second-order vibrational perturbation theory were performed using force fields computed with relativistic coupled-cluster methods. The experimental frequencies are shown to be in good agreement with the computed fundamental frequencies except for ν9 (for CH2IOO) and ν10 (for CH2I(18)O(18)O). Our findings were compared with the study by Lee and Lee conducted in a para-H2 matrix. The fundamental frequencies are in good agreement (within 6 cm(-1)) except for the two low-frequency modes, ν9 (for CH2IOO) and ν10 (for CH2I(18)O(18)O) likely due to different matrix shifts for para-H2 and Ar matrices. In addition, our calculations are in somewhat better agreement with the experiment values than the calculations by Lee and Lee. Our study also shows that reaction CH2I + O2 produces the peroxy radical CH2IOO in cold matrices (10

  14. Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature

    NASA Astrophysics Data System (ADS)

    Xin, X.; Altan, H.; Saint, A.; Matten, D.; Alfano, R. R.

    2006-11-01

    Terahertz time-domain spectroscopy has been used to measure the absorption of water vapor in 0.2-2.4THz range from low to high humidity at room temperature. The observed absorption lines are due to the water molecular rotations in the ground vibrational state. We find that the absorption strength of para transitions increases as humidity increases, while the absorption strength of ortho transitions increases and then decreases in intensity with increasing humidity. We explain this difference based on the nuclear spin statistics based ratio of ortho to para water monomer populations at room temperature. The preferential adsorption on the solid surfaces of para water leads to an ortho dominated vapor cloud whose monomer rotational absorption intensity decreases due to the effects of dimerization, molecular collisions, clustering, and interactions with liquid droplets at high concentrations.

  15. Cavity Ringdown Absorption Spectrum of the T_1 (n,π^{*}) ← S_0 Transition of 2-CYCLOHEXEN-1-ONE

    NASA Astrophysics Data System (ADS)

    Zabronsky, Katherine L.; McAnally, Michael O.; Stupca, Daniel J.; Pillsbury, Nathan R.; Drucker, Stephen

    2013-06-01

    The cavity ringdown (CRD) absorption spectrum of 2-cyclohexen-1-one (CHO) was recorded over the range 401.5-410.5 nm in a room-temperature gas cell. The very weak band system (ɛ ≤ 0.02 dm^3 mol^{-1} {cm}^{-1}) in this region is due to the T_1(n, π*) ← S_0 electronic transition. The 0^0_0 origin band was assigned to the feature observed at {24,558.6 ± 0.3 {cm}^{-1}}. We have assigned about 25 vibronic transitions in a region extending from {-200 to +350 cm^{-1}} relative to the origin band. From these assignments we determined fundamental frequencies for several vibrational modes in the T_1 excited state. The table below compares their frequencies to corresponding values measured for CHO vapor in the S_0 electronic ground state (via far-IR spectroscopy) and the S_1(n, π*) excited state (via near-UV CRD spectroscopy). Low-frequency fundamentals (cm^{-1}) of CHO vapor Mode Description S_0 S_1(n,π^*) T_1(n,π^*) 39 ring twist 99.2 122.1 99.5 38 bend (inversion of C-5) 247 251.9 253.2 37 C=C twist 304.1 303.3 247.8 36 C=O wag 485 343.9 345.5 For ν_{39} and ν_{37}, the differences between S_1 and T_1 frequencies are noteworthy. These differences suggest that the electron delocalization associated with the π^* ← n chromophore in CHO is substantially different for singlet vs. triplet excitation. T. L. Smithson and H. Wieser, J. Chem. Phys. {73}, 2518 (1980) M. Z. M. Rishard and J. Laane, J. Molec. Struct. {976}, 56 (2010). M. Z. M. Rishard, E. A. Brown, L. K. Ausman, S. Drucker and J. Laane, J. Phys. Chem. A {112}, 38 (2008).

  16. Surface vs. atmospheric origin of 2.1-2.5 micron absorption features in the Martian spectrum

    NASA Technical Reports Server (NTRS)

    Bell, James F., III; Crisp, David

    1992-01-01

    For 20 years the origin of subtle absorption features in the spectrum of Mars near 2.3 micro-m ('K' band: 1.9-2.5 micro-m) has been debated. This spectral region contains gaseous absorption features predominantly from CO2 and CO on Mars and from telluric H2O and CO2. The authors have obtained new higher spectral resolution telescopic K band spectra of 10 surface regions using the Infrared Telescope Facility (IRTF) at Mauna Kea during 1990. The goals were to confirm the existence of broad features seen at lower spectral resolution and to determine whether these bands are caused by atmospheric gases, surface (or airborne dust) minerals, or a combination of both.

  17. Quantum Monte Carlo for the x-ray absorption spectrum of pyrrole at the nitrogen K-edge

    SciTech Connect

    Zubarev, Dmitry Yu.; Austin, Brian M.; Lester, William A. Jr.

    2012-04-14

    Fixed-node diffusion Monte Carlo (FNDMC) is used to simulate the x-ray absorption spectrum of a gas-phase pyrrole molecule at the nitrogen K-edge. Trial wave functions for core-excited states are constructed from ground-state Kohn-Sham determinants substituted with singly occupied natural orbitals from configuration interaction with single excitations calculations of the five lowest valence-excited triplet states. The FNDMC ionization potential (IP) is found to lie within 0.3 eV of the experimental value of 406.1 {+-} 0.1 eV. The transition energies to anti-bonding virtual orbitals match the experimental spectrum after alignment of IP values and agree with the existing assignments.

  18. Detection of the 1400 A absorption in the ultraviolet spectrum of the DA white dwarf LB 3303

    NASA Technical Reports Server (NTRS)

    Wegner, G.

    1982-01-01

    Low-resolution ultraviolet International Ultraviolet Explorer spectra of the southern white dwarf LB 3303 show the presence of the wavelength 1400 absorption feature reported by Greenstein in the spectrum of 40 Eri B. The equivalent width is 5.7 A, and the measured wavelength is 1394 A. A comparison of the ultraviolet fluxes with model atmospheres confirms that LB 3303 has an effective temperature near 16,000 K, as found earlier from visual wavelength data. There are still problems with the identification of this line. The star is not hot enough to explain the presence of Si IV, and the agreement with the spectrum of the H2 molecule is not convincing.

  19. A photon counting and a squeezing measurement method by the exact absorption and dispersion spectrum of Λ-type Atoms.

    PubMed

    Naeimi, Ghasem; Alipour, Samira; Khademi, Siamak

    2016-01-01

    Recently, the master equations for the interaction of two-mode photons with a three-level Λ-type atom are exactly solved for the coherence terms. In this paper the exact absorption spectrum is applied for the presentation of a non-demolition photon counting method, for a few number of coupling photons, and its benefits are discussed. The exact scheme is also applied where the coupling photons are squeezed and the photon counting method is also developed for the measurement of the squeezing parameter of the coupling photons. PMID:27610321

  20. H216O absorption spectrum between 22250 and 22800 cm-1: Fourier transform spectroscopy with bright light source

    NASA Astrophysics Data System (ADS)

    Serduykov, V. I.; Sinitsa, L. N.; Vasil'chenko, S. S.; Bykov, A. D.; Kruglova, T. V.; Polovtseva, E. R.; Scherbakov, A. P.

    2014-11-01

    Measurements of water vapor absorption spectra in the visible spectral region near 0.44 mkm are performed using FTspectrometer IFS-125M and Light-emitting diode (LED) as source of radiation. Water vapor spectrum has been obtained by averaging over 17136 scans recorded at 34,8 m optical path length, temperature 24 ± 1 C and pressure of sample 24,8 mBar. Due to strong emission of LED source it was possible to achieve signal-to-noise ratio about 104 and to record weak lines with intensities of 6 10-27 cm/molecule. Comparisons with results of early works are made.

  1. Relative amplitudes of external satellites of superfine-structure multiplets in the saturated absorption spectrum of SiF4

    NASA Astrophysics Data System (ADS)

    Krylov, I. R.; Akulinin, D. A.; Chubykin, A. D.

    2015-08-01

    Variation of amplitudes of Doppler-free saturated absorption resonances as a result of changes in the gas pressure and power of light waves is studied theoretically and experimentally. The results of the investigation are used for the interpretation of weak satellites of superfine-structure multiplets in the spectrum related to tunnel transitions between energy states of a molecule corresponding to its rotation about equivalent symmetry axes. Relative amplitudes of satellites of the AFE and FEF multiplets of the superfine structure of the SiF4 molecule in the frequency tuning interval of a CO2 laser operating at the P(38) line of the 9.7-µm band are studied experimentally. It is confirmed that the variation of relative amplitudes of the satellites is caused mainly by the fact that the magnitudes of the self-induced transparency of the medium that are created by each light wave for itself are different for the main resonances of the multiplet and for their satellites. The discrepancy between the experimental and theoretical dependences of the relative amplitudes of the satellites upon variation of the gas pressure and power of light waves is analyzed. Based on the discovered discrepancy, it is suggested that molecular collisions with Bennett dip or peak transfer contribute to the formation of satellites of the FEF multiplet. Multiphoton processes participate in the formation of one of the multiplets of the FEF multiplet. It is suggested that the power of the light field partially lifts the ban on transitions participating in the formation of satellites of both studied multiplets. Processing of the experimental curves by the leastsquares method revealed spectrally unresolved satellites within the FEF multiplet, which represent crossover resonances between allowed and forbidden transitions. For these satellites, no additional dependence of the amplitude on the laser power or gas pressure was found. The dependence of the amplitude of these satellites is completely

  2. FUSE Detection of Galactic and Intrinsic Absorption in the Spectrum of the Seyfert 1 Galaxy 2MASX J21362313-6224008

    NASA Technical Reports Server (NTRS)

    Bonamente, Massimiliano; VanDykeDixon, W.

    2003-01-01

    We present the far-ultraviolet spectrum of the Seyfert 1 galaxy 2MASX 521362313-6224008 obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). The spectrum features absorption from Galactic O VI at two velocities and redshifted H I Lyman beta and gamma, C II, C III, and O VI. The redshifted absorption features represent a single kinematic component blueshifted by approx. 310 km/s relative to the AGN. We use photoionization models to derive the physical parameters of the absorbing gas. An alternative interpretation for the absorption lines is also proposed, whereby the absorbing gas is associated with an intervening galaxy cluster.

  3. FUSE Observations of Galactic and Intrinsic Absorption in the Spectrum of the Seyfert 1 Galaxy 2MASX J21362313-6224008

    NASA Technical Reports Server (NTRS)

    Bonamente, Massimiliano; Dixon, W. Van Dyke

    2004-01-01

    We present the far-ultraviolet spectrum of the Seyfert 1 galaxy 2MASX J21362313-6224008 obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). The spectrum features absorption from Galactic O VI at two velocities and redshifted H I Ly beta and gamma, C II, CIII, and O VI. The redshifted absorption features represent a single kinematic component blueshifted by approx. 310 km/s relative to the active galactic nucleus. We use photoionization models to derive constraints on the physical parameters of the absorbing gas. An alternative interpretation for the absorption lines is also proposed, wherein the absorbing gas is associated with an intervening galaxy cluster.

  4. Genetic and Functional Analyses of SHANK2 Mutations Suggest a Multiple Hit Model of Autism Spectrum Disorders

    PubMed Central

    Leblond, Claire S.; Heinrich, Jutta; Delorme, Richard; Proepper, Christian; Betancur, Catalina; Huguet, Guillaume; Konyukh, Marina; Chaste, Pauline; Ey, Elodie; Rastam, Maria; Anckarsäter, Henrik; Nygren, Gudrun; Gillberg, I. Carina; Melke, Jonas; Toro, Roberto; Regnault, Beatrice; Fauchereau, Fabien; Mercati, Oriane; Lemière, Nathalie; Skuse, David; Poot, Martin; Holt, Richard; Monaco, Anthony P.; Järvelä, Irma; Kantojärvi, Katri; Vanhala, Raija; Curran, Sarah; Collier, David A.; Bolton, Patrick; Chiocchetti, Andreas; Klauck, Sabine M.; Poustka, Fritz; Freitag, Christine M.; Waltes, Regina; Kopp, Marnie; Duketis, Eftichia; Bacchelli, Elena; Minopoli, Fiorella; Ruta, Liliana; Battaglia, Agatino; Mazzone, Luigi; Maestrini, Elena; Sequeira, Ana F.; Oliveira, Barbara; Vicente, Astrid; Oliveira, Guiomar; Pinto, Dalila; Scherer, Stephen W.; Zelenika, Diana; Delepine, Marc; Lathrop, Mark; Bonneau, Dominique; Guinchat, Vincent; Devillard, Françoise; Assouline, Brigitte; Mouren, Marie-Christine; Leboyer, Marion; Gillberg, Christopher; Boeckers, Tobias M.; Bourgeron, Thomas

    2012-01-01

    Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disorders with a complex inheritance pattern. While many rare variants in synaptic proteins have been identified in patients with ASD, little is known about their effects at the synapse and their interactions with other genetic variations. Here, following the discovery of two de novo SHANK2 deletions by the Autism Genome Project, we identified a novel 421 kb de novo SHANK2 deletion in a patient with autism. We then sequenced SHANK2 in 455 patients with ASD and 431 controls and integrated these results with those reported by Berkel et al. 2010 (n = 396 patients and n = 659 controls). We observed a significant enrichment of variants affecting conserved amino acids in 29 of 851 (3.4%) patients and in 16 of 1,090 (1.5%) controls (P = 0.004, OR = 2.37, 95% CI = 1.23–4.70). In neuronal cell cultures, the variants identified in patients were associated with a reduced synaptic density at dendrites compared to the variants only detected in controls (P = 0.0013). Interestingly, the three patients with de novo SHANK2 deletions also carried inherited CNVs at 15q11–q13 previously associated with neuropsychiatric disorders. In two cases, the nicotinic receptor CHRNA7 was duplicated and in one case the synaptic translation repressor CYFIP1 was deleted. These results strengthen the role of synaptic gene dysfunction in ASD but also highlight the presence of putative modifier genes, which is in keeping with the “multiple hit model” for ASD. A better knowledge of these genetic interactions will be necessary to understand the complex inheritance pattern of ASD. PMID:22346768

  5. Photodissociation of carbon dioxide in singlet valence electronic states. II. Five state absorption spectrum and vibronic assignment

    NASA Astrophysics Data System (ADS)

    Grebenshchikov, Sergy Yu.

    2013-06-01

    The absorption spectrum of CO2 in the wavelength range 120-160 nm is analyzed by means of quantum mechanical calculations performed using vibronically coupled potential energy surfaces of five singlet valence electronic states and the coordinate dependent transition dipole moment vectors. The thermally averaged spectrum, calculated for T = 190 K via Boltzmann averaging of optical transitions from many initial rotational states, accurately reproduces the experimental spectral envelope, consisting of a low and a high energy band, the positions of the absorption maxima, their FWHMs, peak intensities, and frequencies of diffuse structures in each band. Contributions of the vibronic interactions due to Renner-Teller coupling, conical intersections, and the Herzberg-Teller effect are isolated and the calculated bands are assigned in terms of adiabatic electronic states. Finally, diffuse structures in the calculated bands are vibronically assigned using wave functions of the underlying resonance states. It is demonstrated that the main progressions in the high energy band correspond to consecutive excitations of the pseudorotational motion along the closed loop of the CI seam, and progressions differ in the number of nodes along the radial mode perpendicular to the closed seam. Irregularity of the diffuse peaks in the low energy band is interpreted as a manifestation of the carbene-type "cyclic" OCO minimum.

  6. Two-photon-absorption spectrum of poly(di- n -hexylsilane) films

    SciTech Connect

    Soos, Z.G. ); Kepler, R.G. )

    1991-05-15

    Two-photon-absorption (TPA) spectra of poly(di-{ital n}-hexylsilane) (PDHS) films are obtained from 605 to 410 nm at 295 and 11 K, where the intensity is an order of magnitude higher. A strong TPA band is found above 5 eV and interpreted in terms of interacting {sigma} electrons in a Pariser-Parr-Pople (PPP) model. PPP models for (Si){sub {ital n}} chains relate the excitonic (one-photon) absorption at {ital E}{sub {ital g}}=3.4 in PDHS to the 4.2-eV TPA at the alternation gap and the high-energy TPA derived from two-electron excitations at {ital E}{sub {ital g}}. The smaller alternation gap in {pi}-conjugated polymers and their intense TPA above {ital E}{sub {ital g}} also indicate correlated states and differ qualitatively from single-particle descriptions.

  7. Near-infrared spectrum of ZrF by intracavity laser absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Harms, Jack C.; O'Brien, Leah C.; Ni, Ann; Mahkdoom, Bilal; O'Brien, James J.

    2015-04-01

    The (1, 1) band of the CΩ = 3/2 - X2Δ3/2 transition of ZrF has been recorded at high resolution using intracavity laser absorption spectroscopy. The ZrF molecules were produced using a Zr-lined copper hollow cathode sputter source with a trace amount of SF6 as a fluoride source. Molecular constants from the analysis are presented and compared with previous work.

  8. Visible-band (390-940nm) monitoring of the Pluto absorption spectrum during the New Horizons encounter

    NASA Astrophysics Data System (ADS)

    Smith, Robert J.; Marchant, Jonathan M.

    2015-11-01

    Whilst Earth-based observations obviously cannot compete with New Horizons’ on-board instrumentation in most regards, the New Horizons data set is essentially a snapshot of Pluto in July 2015. The New Horizons project team therefore coordinated a broad international observing campaign to provide temporal context and to take advantage of the once-in-a-lifetime opportunity to directly link our Earth-based view of Pluto with “ground truth” provided by in situ measurements. This both adds value to existing archival data sets and forms the basis of long term, monitoring as we watch Pluto recede from the Sun over the coming years. We present visible-band (390-940nm) monitoring of the Pluto absorption spectrum over the period July - October 2015 from the Liverpool Telescope (LT). In particular we wished to understand the well-known 6-day fluctuation in the methane ice absorption spectrum which is observable from Earth in relation to the never-before-available high resolution maps of the Pluto surface. The LT is a fully robotic 2.0m optical telescope that automatically and dynamically schedules observations across 30+ observing programmes with a broad instrument suite. It is ideal for both reactive response to dynamic events (such as the fly-by) and long term, stable monitoring with timing constraints individually optimised to the science requirements of each programme. For example past studies of the observed CH4 absorption variability have yielded ambiguity of whether they were caused by real physical changes or geometric observation constraints, in large part because of the uneven time sampling imposed by traditional telescope scheduling.

  9. Fourier-analytic technique for the separation of the signature of atmospheric ClO absorption from the solar background spectrum in the near ultraviolet

    SciTech Connect

    Burnett, E.B.

    1989-02-01

    The high-resolution ClO absorption signature in the region of 308.1 nm has a very low absorption fraction, of the order of 6 x 10/sup -5/, and linewidths comparable with those of the solar background spectrum. Because of the need for reliable absorption measurements of the abundance of this species, which is important in ozone photochemistry, a Fourier-analysis-based technique for the deconvolution of atmospheric solar absorption spectra in this region has been developed. The technique utilizes the regularity of the ClO spectrum and results in a significant reduction in the minimum signal-to-noise required for the retrieval of ClO abundances from absorption spectra.

  10. Research of fiber carbon dioxide sensing system based laser absorption spectrum

    NASA Astrophysics Data System (ADS)

    Wei, Yubin; Zhang, Tingting; Li, Yanfang; Zhao, Yanjie; Wang, Chang; Liu, Tongyu

    2012-02-01

    Carbon dioxide is one of the important gas need to be detected in coal mine safety. In the mine limited ventilation environment, Concentration of carbon dioxide directly affects the health of coal miners. Carbon dioxide is also one of important signature Gas in spontaneous combustion forecasting of coal goaf area, it is important to accurately detect concentration of carbon dioxide in coal goaf area. This paper proposed a fiber carbon dioxide online sensing system based on tunable diode laser spectroscopy. The system used laser absorption spectroscopy and optical fiber sensors combined, and a near-infrared wavelength 1608nm fiber-coupled distributed feedback laser (DFB) as a light source and a 7cm length gas cell, to achieve a high sensitivity concentration detection of carbon dioxide gas. The technical specifications of sensing system can basically meet the need of mine safety.

  11. A Near-Infrared Spectrometer to Measure Zodiacal Light Absorption Spectrum

    NASA Technical Reports Server (NTRS)

    Kutyrev, A. S.; Arendt, R.; Dwek, E.; Kimble, R.; Moseley, S. H.; Rapchun, D.; Silverberg, R. F.

    2010-01-01

    We have developed a high throughput infrared spectrometer for zodiacal light fraunhofer lines measurements. The instrument is based on a cryogenic dual silicon Fabry-Perot etalon which is designed to achieve high signal to noise Fraunhofer line profile measurements. Very large aperture silicon Fabry-Perot etalons and fast camera optics make these measurements possible. The results of the absorption line profile measurements will provide a model free measure of the zodiacal Light intensity in the near infrared. The knowledge of the zodiacal light brightness is crucial for accurate subtraction of zodiacal light foreground for accurate measure of the extragalactic background light after the subtraction of zodiacal light foreground. We present the final design of the instrument and the first results of its performance.

  12. Detection of a Deep 3-μm Absorption Feature in the Spectrum of Amalthea (JV)

    NASA Astrophysics Data System (ADS)

    Takato, Naruhisa; Bus, Schelte J.; Terada, Hiroshi; Pyo, Tae-Soo; Kobayashi, Naoto

    2004-12-01

    Near-infrared spectra of Jupiter's small inner satellites Amalthea and Thebe are similar to those of D-type asteroids in the 0.8- to 2.5-micrometer wavelength range. A deep absorption feature is detected at 3 micrometers in the spectra of the trailing side of Amalthea, which is similar to that of the non-ice components of Callisto and can be attributed to hydrous minerals. These surface materials cannot be explained if the satellite formed at its present orbit by accreting from a circumjovian nebula. Amalthea and Thebe may be the remnants of Jupiter's inflowing building blocks that formed in the outer part or outside of the circumjovian nebula.

  13. Detection of a deep 3-microm absorption feature in the spectrum of Amalthea (JV).

    PubMed

    Takato, Naruhisa; Bus, Schelte J; Terada, Hiroshi; Pyo, Tae-Soo; Kobayashi, Naoto

    2004-12-24

    Near-infrared spectra of Jupiter's small inner satellites Amalthea and Thebe are similar to those of D-type asteroids in the 0.8- to 2.5-micrometer wavelength range. A deep absorption feature is detected at 3 micrometers in the spectra of the trailing side of Amalthea, which is similar to that of the non-ice components of Callisto and can be attributed to hydrous minerals. These surface materials cannot be explained if the satellite formed at its present orbit by accreting from a circumjovian nebula. Amalthea and Thebe may be the remnants of Jupiter's inflowing building blocks that formed in the outer part or outside of the circumjovian nebula. PMID:15618511

  14. Anomalously Broad Diffuse Interstellar Bands and Excited CH+ Absorption in the Spectrum of Herschel 36

    NASA Astrophysics Data System (ADS)

    York, D. G.; Dahlstrom, J.; Welty, D. E.; Oka, T.; Hobbs, L. M.; Johnson, S.; Friedman, S. D.; Jiang, Z.; Rachford, B. L.; Snow, T. P.; Sherman, R.; Sonnentrucker, P.

    2014-02-01

    Anomalously broad diffuse interstellar bands (DIBs) at 5780.5, 5797.1, 6196.0, and 6613.6 Å are found in absorption along the line of sight to Herschel 36, an O star system next to the bright Hourglass nebula of the Hii region Messier 8. Excited lines of CH and CH+ are seen as well. We show that the region is very compact and itemize other anomalies of the gas. An infrared-bright star within 400 AU is noted. The combination of these effects produces anomalous DIBs, interpreted by Oka et al. (2013, see also this volume) as being caused predominantly by infrared pumping of rotational levels of relatively small molecules.

  15. Theory and experiment of coherent wave packet dynamics in rare earth solids: Absorption spectrum vs femtosecond fringe-resolved interferogram

    NASA Astrophysics Data System (ADS)

    Luo, Q.; Dai, D. C.; Wang, G. Q.; Ninulescu, V.; Yu, X. Y.; Luo, L.; Zhou, J. Y.; Yan, YiJing

    2001-01-01

    Coherent dynamic property of neodymium yttrium aluminum garnet (Nd:YAG) crystal at 77 K is studied via the conventional absorption, the femtosecond fringe-resolved wave packet interferometry, and the related difference-phase spectrum. The recorded interferogram exhibits beatings in subpicosecond time scale arising from the interferences among various weakly split 4f-electronic states and the coupled vibronic optical phonon sidebands. The electron-phonon coupling in Nd:YAG can be well described by multiple Brownian oscillators model involving in each individual electronic transition. The parameters for characterizing material coherence and relaxation are determined via the theoretical modelings of both the frequency and the time-domain experimental signals.

  16. A HIRES Detection of NA I D Absorption in the Spectrum of the QSO PKS 2020-370 Due to the Galaxy Klemola 31A

    NASA Astrophysics Data System (ADS)

    Junkkarinen, V. T.; Barlow, T. A.

    1994-12-01

    By using the Keck telescope and HIRES spectrograph we have detected Na I D absorption lines in the spectrum of the QSO PKS 2020-370 (V = 17.5, z = 1.048) due to the galaxy Klemola 31A (z = 0.0288). The PKS 2020-370 line of sight is near an apparent spiral arm only 20" from the nucleus of Klemola 31A which corresponds to 17 kpc (H_o = 50 km s(-1) Mpc(-1) ). The spectrum of PKS 2020-370 has strong Ca II absorption lines (W_λ ~ 350 m Angstroms \\ for the K line) at the galaxy redshift (Boksenberg et al, 1980, ApJ, 242, L145), but previous attempts to detect Na I have resulted in upper limits (Boisse et al. 1988, A&A, 191, 193, Womble, 1992, thesis UCSD). We observed PKS 2020-370 with HIRES in May 1994 at a resolution of 8 km s(-1) FWHM for a total of 90 minutes. The Na I D doublet is detected with a total W_λ for the Na I 5891.6 Angstroms \\ (vac) absorption line of about 160 m Angstroms . The absorption appears as two main velocity components separated by 23 km s(-1) . The optically thin estimate for N(Na I) = 1.0 times 10(12) cm(-2) gives an estimated N(Ca II)/N(Na I) = 5. This value suggests that the gas in Klemola 31A along the QSO line of sight is ``halo like''. Along ``disk like'' lines of sight where Ca is thought to be depleted onto grains in our Galaxy, the N(Ca II)/N(Na I) ratio is usually small (<= 1). Other QSO--galaxy pairs often show disk like N(Ca II)/N(Na I) ratios when the line of sight intersects starlight at 25 mag per sq. arcsec (Womble, 1992 thesis UCSD). The PKS 2020-370 sightline is near the optical extent of Klemola 31A but the N(Ca II)/N(Na I) is consistent with the sightline passing through two clouds in the halo. This research has been supported in part by NASA NAS5--29293 and NAG5--1630.

  17. Highly Ionized Iron Absorption Lines from Outflowing Gases in the X-ray Spectrum of NGC 1365

    NASA Technical Reports Server (NTRS)

    Risaliti, G.; Bianchi, S.; Matt, G.; Baldi, A.; Elvis, M.; Fabbiano, G.; Zezas, A.

    2006-01-01

    We present the discovery of four absorption lines in the X-ray spectrum of the Seyfert galaxy NGC 1365, at energies between 6.7 and 8.3 keV. The lines are detected with high statistical confidence (from >20 sigma for the strongest to -4 sigma for the weakest) in two XMM-Newton observations 60 ks long. We also detect the same lines, with a lower signal-to-noise ratio (but still >2 sigma for each line), in two previous shorter (-10 ks) XMM-Newton observations. The spectral analysis identifies these features as Fe XXV and Fe XXVI Kalpha and Kbeta lines, outflowing with velocities varying between -1000 and -5000 km/s among the observations. These are the highest quality detections of such lines so far. The high equivalent widths [EW (Kalpha) approximately 100 eV] and the Kalpha/Kbeta ratios imply that the lines are due to absorption of the AGN continuum by a highly ionized gas with column density NH-5?1023 cm(exp -2) at a distance of -(50-100)RS from the continuum source.

  18. The Fourier transform absorption spectrum of acetylene between 8280 and 8700 cm-1

    NASA Astrophysics Data System (ADS)

    Lyulin, O. M.; Vander Auwera, J.; Campargue, A.

    2016-07-01

    High resolution (0.011 cm-1) room temperature (295 K) Fourier transform absorption spectra (FTS) of acetylene have been analyzed in the 8280-8700 cm-1 range dominated by the ν1+ν2+ν3 band at 8512 cm-1. Line positions and intensities were retrieved from FTS spectra recorded at 3.84 and 56.6 hPa. As a result, a list of 1001 lines was constructed with intensities ranging between about 2×10-26 and 10-22 cm/molecule. Comparison with accurate predictions provided by a global effective operator model led to the assignment of 629 12C2H2 lines. In addition, 114 lines of the 13C12CH2 isotopologue were assigned using information available in the literature. The 12C2H2 lines belong to thirteen bands, nine of which being newly reported. The 13C12CH2 lines belong to three bands, the intensities of which being reported for the first time. Spectroscopic parameters of the 12C2H2 upper vibrational levels were derived from band-by-band analyses of the line positions (typical rms are on the order of 0.002 cm-1). Three of the analyzed bands were found to be affected by rovibrational perturbations, which are discussed in the frame of a global effective Hamiltonian. The obtained line parameters are compared with those of the two bands included in the HITRAN 2012 database.

  19. [Measurements of IR absorption across section and spectrum simulation of lewisite].

    PubMed

    Zhang, Yuan-peng; Wang, Hai-tao; Zhang, Lin; Yang, Liu; Guo, Xiao-di; Bai, Yun; Sun, Hao

    2015-02-01

    The vapor infrared transmission spectra of varied concentration of lewisite-1 were measured by a long-path FT-IR spectrometer, and its characteristic frequencies are 814, 930, 1563 cm(-1); their infrared absorption cross section (a) were determined using Beer-Lambert law. The corresponding sigma values are 3.89 +/- 0.01, 1.43 +/- 0.06, 4.47 +/- 0.05 ( X 10(-20) cm2 x molecule(-1)). Two little teeny peaks, 1158, 1288 cm(-1) were found in the measured spectra. Density Functional Theory (DFT) was applied to calculated the infrared spectra of lewisite-1, -2, -3 on a b3lyp/6-311+g(d, p) level by Gauss09 package. The vibration modes were assigned by Gaussview5. 08. The calculated spectra and experimental spectra are in good agreement with each other in 600-1600 cm(-1) range, for the Person's r is 0.9991. The calculated spectra also showed three characteristic frequencies (293, 360, 374 cm(-1)) related to As atom. 0.977 was a scaling factor we determined for lewisite-1 through least-square error and its performance to scale lewisite-1, -2, -3 was acceptable. The results of this work are useful for monitoring environmental atmospheric concentrations of lewisite. PMID:25970914

  20. Theory of the electronic states and absorption spectrum of the LiCl:Ag+ impurity system

    NASA Astrophysics Data System (ADS)

    Jackson, Koblar A.; Lin, Chun C.

    1990-01-01

    The impurity absorption spectra of Ag+ and Cu+ impurities in alkali halide hosts show characteristically different features, despite the similar nature of the corresponding free ions. We use the self-interaction-corrected local-spin-density (SIC-LSD) theory to calculate the electronic structure of the ground state (4d) and the 5s and 5p excited states of the LiCl:Ag+ impurity ion. The method of linear combinations of atomic orbitals is used to determine the wave functions and energy levels. By comparing with previous calculations for LiCl:Cu+, we are able to attribute the differences in the d-->s and d-->p transitions in the ultraviolet spectra of these systems to the increased bonding between host crystal and impurity orbitals in LiCl:Ag+, due to the more extensive nature of the Ag+ 4d orbitals. A modification of the earlier SIC-LSD impurity-crystal procedure is introduced to treat the strongly mixed impurity states.

  1. Optoelectronic set for measuring the absorption spectrum of the thin biological media

    NASA Astrophysics Data System (ADS)

    Gryko, Lukasz; Zajac, Andrzej; Gilewski, Marian

    2013-10-01

    In the paper the authors present the developed optoelectronic system for controlled, repetitive exposure by electromagnetic radiation of biological structures in the Low Level Laser (LED) Therapy procedures. The set allows for objective selection and control of the irradiation parameters by light from spectral range of the tissues transmission window. Measurements of optical parameters of thin biological medium - spectral absorption coefficient and the amount of absorbed energy - can be implemented in the measuring chamber during irradiation treatment. The radiation source is the broadband illuminator consists of set of selected high power LEDs. The maximum optical power of single source is from 80 mW to 800 mW. Illuminator is controlled and powered by the multi-channel prototype control system, which allows independently control a current of each emitter. This control allows shaping spectral emission characteristic of broadband source in range 600-1000 nm. Illuminator allows providing in the working area of 700 cm2 a uniform distribution of optical power density, of 10 mW/cm2 for maximum. Set ensure uniform distribution of the spectral power density of up to 40 mW/nm.

  2. Total Absorption Spectroscopy Study of ⁹²Rb Decay: A Major Contributor to Reactor Antineutrino Spectrum Shape

    DOE PAGESBeta

    Sonzogni, A.; Zakari-Issoufou, A. -A.; Fallot, M.; Porta, A.; Algora, A.; Tain, J. L.; Valencia, E.; Rice, S.; Bui, V. M.; Cormon, S.; et al

    2015-03-09

    The accurate determination of the emitted reactor antineutrino flux is still a major challenge for actual and future neutrino experiments at reactors, especially after the evidence of a disagreement between the measured antineutrino energy spectrum by Double Chooz, Daya Bay, and Reno and calculated antineutrino spectra obtained from the conversion of the unique integral beta spectra measured at the ILL reactor. Using nuclear data to compute reactor antineutrino spectra may help understanding this bias, with the study of the underlying nuclear physics. Summation calculations allow identifying a list of nuclei that contribute importantly to the antineutrino energy spectra emitted aftermore » the fission of ²³⁹,²⁴¹Pu and ²³⁵,²³⁸U, and whose beta decay properties might deserve new measurements. Among these nuclei, ⁹²Rb exhausts by itself about 16% of of the antineutrino energy spectrum emitted by Pressurized Water Reactors in the 5 to 8 MeV range. In this Letter, we report new Total Absorption Spectroscopy (TAS) results for this important contributor. The obtained beta feeding from ⁹²Rb shows beta intensity unobserved before in the 4.5 to 5.5 MeV energy region and gives a ground state to ground state branch of 87.5 % ± 3%. These new data induce a dramatic change in recent summation calculations where a 51% GS to GS branch was considered for ⁹²Rb, increasing the summation antineutrino spectrum in the region nearby the observed bias.The new data still have an important impact on other summation calculations in which more recent data were considered« less

  3. Total Absorption Spectroscopy Study of ⁹²Rb Decay: A Major Contributor to Reactor Antineutrino Spectrum Shape

    SciTech Connect

    Sonzogni, A.; Zakari-Issoufou, A. -A.; Fallot, M.; Porta, A.; Algora, A.; Tain, J. L.; Valencia, E.; Rice, S.; Bui, V. M.; Cormon, S.; Estienne, M.; Agramunt, J.; Aysto, J.; Bowry, M.; Briz Monago, J. A.; Caballero-Folch, R.; Cano-Ott, D.; Cucoanes, A.; Eloma, V.; Estvez, E.; Farrelly, G. F.; Garcia, A.; Gelletly, W.; Gomez-Hornillos, M. B.; Gorlychev, V.; Hakala, J.; Jokinen, A.; Jordan, M. D.; Kankainen, A.; Kondev, F. G.; Martinez, T.; Mendoza, E.; Molina, F.; Moore, I.; Perez, A.; Podolyak, Zs.; Penttil, H.; Regan, P. H.; Shiba, T.; Rissanen, J.; Rubio, B.; Weber, C.

    2015-03-09

    The accurate determination of the emitted reactor antineutrino flux is still a major challenge for actual and future neutrino experiments at reactors, especially after the evidence of a disagreement between the measured antineutrino energy spectrum by Double Chooz, Daya Bay, and Reno and calculated antineutrino spectra obtained from the conversion of the unique integral beta spectra measured at the ILL reactor. Using nuclear data to compute reactor antineutrino spectra may help understanding this bias, with the study of the underlying nuclear physics. Summation calculations allow identifying a list of nuclei that contribute importantly to the antineutrino energy spectra emitted after the fission of ²³⁹,²⁴¹Pu and ²³⁵,²³⁸U, and whose beta decay properties might deserve new measurements. Among these nuclei, ⁹²Rb exhausts by itself about 16% of of the antineutrino energy spectrum emitted by Pressurized Water Reactors in the 5 to 8 MeV range. In this Letter, we report new Total Absorption Spectroscopy (TAS) results for this important contributor. The obtained beta feeding from ⁹²Rb shows beta intensity unobserved before in the 4.5 to 5.5 MeV energy region and gives a ground state to ground state branch of 87.5 % ± 3%. These new data induce a dramatic change in recent summation calculations where a 51% GS to GS branch was considered for ⁹²Rb, increasing the summation antineutrino spectrum in the region nearby the observed bias.The new data still have an important impact on other summation calculations in which more recent data were considered

  4. New narrow infrared absorption features in the spectrum of Io between 3600 and 3100 cm (2.8-3.2 micrometers)

    NASA Technical Reports Server (NTRS)

    Sandford, Scott A.; Geballe, Thomas R.; Salama, Farid; Goorvitch, David

    1994-01-01

    We report the discovery of a series of infrared absorption bands between 3600 and 3100/cm (2.8-3.2 micrometers) in the spectrum of Io. Individual narrow bands are detected at 3553, 3514.5, 3438, 3423, 3411.5, and 3401/cm (2.815, 2.845, 2.909, 2.921, 2.931, and 2.940 micrometers, respectively). The positions and relative strengths of these bands, and the difference of their absolute strengths between the leading and trailing faces of Io, indicate that they are due to SO2. The band at 3438/cm (2.909 micrometers) could potentially have a contribution from an additional molecular species. The existence of these bands in the spectrum of Io indicates that a substantial fraction of the SO2 on Io must reside in transparent ices having relatively large crystal sizes. The decrease in the continuum observed at the high frequency ends of the spectra is probably due to the low frequency side of the recently detected, strong 3590/cm (2.79 micrometer) feature. This band is likely due to the combination of a moderately strong SO2 band and an additional absorption from another molecular species, perhaps H2O isolated in SO2 at low concentrations. A broad (FWHM approximately = 40-60/cm), weak band is seen near 3160/cm (3.16 micrometers) and is consistent with the presence of small quantities of H2O isolated in SO2-rich ices. There is no evidence in the spectra for the presence of H2O vapor on Io. Thus, the spectra presented here neither provide unequivocal evidence for the presence of H2O on Io nor preclude it at the low concentrations suggested by past studies.

  5. The spectral variability of the GHZ-Peaked spectrum radio source PKS 1718-649 and a comparison of absorption models

    SciTech Connect

    Tingay, S. J.; Macquart, J.-P.; Wayth, R. B.; Trott, C. M.; Emrich, D.; Collier, J. D.; Wong, G. F.; Rees, G.; Stevens, J.; Carretti, E.; Callingham, J. R.; Gaensler, B. M.; McKinley, B.; Briggs, F.; Bernardi, G.; Bowman, J. D.; Cappallo, R. J.; Corey, B. E.; Deshpande, A. A.; Goeke, R.; and others

    2015-02-01

    Using the new wideband capabilities of the ATCA, we obtain spectra for PKS 1718-649, a well-known gigahertz-peaked spectrum radio source. The observations, between approximately 1 and 10 GHz over 3 epochs spanning approximately 21 months, reveal variability both above the spectral peak at ∼3 GHz and below the peak. The combination of the low- and high-frequency variability cannot be easily explained using a single absorption mechanism, such as free–free absorption or synchrotron self-absorption. We find that the PKS 1718-649 spectrum and its variability are best explained by variations in the free–free optical depth on our line of sight to the radio source at low frequencies (below the spectral peak) and the adiabatic expansion of the radio source itself at high frequencies (above the spectral peak). The optical depth variations are found to be plausible when X-ray continuum absorption variability seen in samples of active galactic nuclei is considered. We find that the cause of the peaked spectrum in PKS 1718-649 is most likely due to free–free absorption. In agreement with previous studies, we find that the spectrum at each epoch of observation is best fit by a free–free absorption model characterized by a power-law distribution of free–free absorbing clouds. This agreement is extended to frequencies below the 1 GHz lower limit of the ATCA by considering new observations with Parkes at 725 MHz and 199 MHz observations with the newly operational Murchison Widefield Array. These lower frequency observations argue against families of absorption models (both free–free and synchrotron self-absorption) that are based on simple homogenous structures.

  6. Global Properties of the Ejecta Absorptions in the Spectrum of Eta Carinae

    NASA Astrophysics Data System (ADS)

    Gull, T. R.; Vieira, G. L.; Danks, A. C.

    2002-12-01

    Between 2400A to 3160A, we have identified approximately 500 absorption line complexes, each with up to 20 velocity components. Lines of Fe I, Fe II, Ti II, V II, Ni II, Co II, Mn II, Mg I, Mg II and Na I have been identified. Surprisingly, most of the lines originate from energy levels significantly above the ground level. This is indicative of optical pumping from the Central Source. Line widths and population of various levels are non-thermal. The relative column densities change with velocity. For example, Fe II column densities for one transition arising from 0.1eV increase with ejecta velocity while Fe II column densities for another transition decreases with velocity. This may be due to softening of the ultraviolet radiation that pumps the various ions (neutrals) with velocity. If we assume that the distance of each system scales with distance from the Central Source, only a thirty percent change in distance is noted; yet the ratio of column densities for the Fe II examples given above changes by nearly thirty-fold. If the ejecta distance scales with distance from Eta Carinae, then it is likely that this ejecta originated at nearly the same time. The geometry of the Homunculus has been determined to be a double-lobed structure tilted out of the plane of the sky. We interpret the ejecta as being in the wall of the Southwest lobe, and that this wall just happens to be in line of sight from Eta Carinae to the observer. As Eta Carinae enters into the upcoming minimum, we are already seeing some evidence for changes in column densities due to changes in ultraviolet fluxes. This is reinforced by IUE observations that we have recently re-analyzed with respect to the 5.52 year (2020+/-10 days) spectroscopic period. Observations were done through STScI and funding was through the STIS GTO resources.

  7. Global Properties of the Ejecta Absorptions in the Spectrum of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Gull, T. R.; Vieira, G.; Danks, A.

    2003-01-01

    Between 2400A to 3160A, we have identified approximately 500 absorption line complexes, each with up to 20 velocity components. Lines of Fe I, Fe II, Ti II, V II, Ni II, Co II, Mn II, Mg I, Mg II and Na I have been identified. Surprisingly, most of the lines originate from energy levels significantly above the ground level. This is indcative of optical pumping from the Central Source. Line widths and population of various levels are non-thermal. The relative column densities change with velocity. For example, Fe 11 column densities for one transition arising from approx. 0.l ev increase with ejecta velocity while Fe 11 column densities for another transition decreases with velocity. This may be due to softening of the ultraviolet radiation that pumps the various ions (neutrals) with velocity. If we assume that the distance of each system scales with distance from the Central Source, only a thirty percent change in distance is noted; yet the ratio of column densities for the Fe I1 examples given above changes by nearly thirty-fold. If the ejecta distance scales with distance from Eta Carinae, then it is likely that this ejecta originated at nearly the same time. The geometry of the Homunculus has been determined to be a double-lobed structure tilted out of the plane of the sky. We interpret the ejecta as being in the wall of the Southwest lobe, and that this wall just happens to be in line of sight from Eta Carinae to the observer. As Eta Carinae enters into the upcoming minimum, we are already seeing some evidence for changes in column densities due to changes in ultraviolet fluxes. This is reinforced by IUE observations that we have recently re-analyzed with respect to the 5.52 year (2020 +/- 10 days) spectroscopic period. Observations were done through STScI and funding was through the STIS GTO resources.

  8. The 5f2-->5f16d1 absorption spectrum of Cs2GeF6:U4+ crystals: A quantum chemical and experimental study.

    PubMed

    Ordejón, Belén; Karbowiak, Miroslaw; Seijo, Luis; Barandiarán, Zoila

    2006-08-21

    Single crystals of U(4+)-doped Cs2GeF6 with 1% U4+ concentration have been obtained by the modified Bridgman-Stockbarger method in spite of the large difference in ionic radii between Ge4+ and U4+ in octahedral coordination. Their UV absorption spectrum has been recorded at 7 K, between 190 and 350 nm; it consists of a first broad and intense band peaking at about 38,000 cm(-1) followed by a number of broad bands of lower intensity from 39,000 to 45,000 cm(-1). None of the bands observed shows appreciable fine vibronic structure, so that the energies of experimental electronic origins cannot be deduced and the assignment of the experimental spectrum using empirical methods based on crystal field theory cannot be attempted. Alternatively, the profile of the absorption spectrum has been obtained theoretically using the U-F bond lengths and totally symmetric vibrational frequencies of the ground 5f2 - 1A(1g) and 5f16d(t(2g))1 - iT(1u) excited states, their energy differences, and their corresponding electric dipole transition moments calculated using the relativistic ab initio model potential embedded cluster method. The calculations suggest that the observed bands are associated with the lowest five 5f2 - 1A(1g)-->5f16d(t(2g))1 - iT(1u) (i = 1-5) dipole allowed electronic origins and their vibrational progressions. In particular, the first broad and intense band peaking at about 38,000 cm(-1) can be safely assigned to the 0-0 and 0-1 members of the a(1g) progression of the 5f2 - 1A(1g)-->5f16d(t(2g))1 - 1T(1u) electronic origin. The electronic structure of all the states with main configurational character 5f16d(t(2g))1 has been calculated as well. The results show that the lowest crystal level of this manifold is 5f16d(t(2g))1 - 1E(u) and lies about 6200 cm(-1) above the 5f2 level closest in energy, which amounts to some 11 vibrational quanta. This large energy gap could result in low nonradiative decay and efficient UV emission, which suggest the interest of

  9. Solvent effects on the electronic absorption spectrum of camphor using continuum, discrete or explicit approaches

    NASA Astrophysics Data System (ADS)

    Kongsted, Jacob; Mennucci, Benedetta; Coutinho, Kaline; Canuto, Sylvio

    2010-01-01

    We address the effect of solvation on the lowest electronic excitation energy of camphor. The solvents considered represent a large variation in-solvent polarity. We consider three conceptually different ways of accounting for the solvent using either an implicit, a discrete or an explicit solvation model. The solvatochromic shifts in polar solvents are found to be in good agreement with the experimental data for all three solvent models. However, both the implicit and discrete solvation models are less successful in predicting solvatochromic shifts for solvents of low polarity. The results presented suggest the importance of using explicit solvent molecules in the case of nonpolar solvents.

  10. Reconstruction of a 6-MeV bremsstrahlung spectrum by multi-layer absorption based on LiF:Mg, Cu, P

    NASA Astrophysics Data System (ADS)

    Huang, Jian-Wei; Wang, Nai-Yan

    2014-10-01

    In this paper, TLD (LiF: Mg, Cu, P) is used as detector. A multi-layer absorption (MLA) model is designed. Combined with Monte-Carlo processes, a bremsstrahlung X-ray spectrum is reconstructed by an iterative method; the reconstructed results agree with the results of simulations by the MCNP process essentially, especially in middle energy region.

  11. Interstellar absorption lines in the spectrum of sigma Sco using Copernicus observations

    NASA Technical Reports Server (NTRS)

    Allen, M. M.; Snow, T. P.

    1986-01-01

    Since the launch of Copernicus in 1972, studies have been made of the depletion of gas-phase elements onto dust grains. A few stars have been studied in detail, resulting in a standard depletion pattern which has since been used for comparison. Recent developments, however, have suggested that this standard pattern may need to be re-examined. Some weak, semi-forbidden lines were detected recently which may be able to resolve some of the ambiguities. Studies of single elements have shown that depletion of carbon and oxgyen are much smaller than previously determined. The high resolution ultraviolet spectral scans of sigma Sco were originally made in 1973, but have only recently been analyzed. All these stars are bright and moderately reddened. All four stars will be analyzed in detail, but sigma Sco is the first one completed. The data has broad coverage of ions, making these stars excellent candidates for determination of accurate depletions. A profile-fitting analysis was used rather than curves-of-growth in order to determine separate abundances and depletions in components separated by several km/sec.

  12. Quick measurement of continuous absorption spectrum in ion beam pulse radiolysis: Application of optical multi-channel detector into transient species observation

    NASA Astrophysics Data System (ADS)

    Iwamatsu, Kazuhiro; Muroya, Yusa; Yamashita, Shinichi; Kimura, Atsushi; Taguchi, Mitsumasa; Katsumura, Yosuke

    2016-02-01

    A quick measurement system of a continuous absorption spectrum covering a wide range from 200 to 950 nm was constructed by employing an optical multi-channel detector. Ion beam pulse radiolysis with 12.5 MeV/u He, 18.3 MeV/u C and 17.5 MeV/u Ne ions were performed with the measurement system. Transient absorption spectrum of (S C N) 2 • - was clearly observed in KSCN aqueous solutions within a few minutes in spite of their very small absorbance, demonstrating high sensitivity of 0.001-0.003 in absorbance in the range from 260 to 660 nm as well as short measurement time of a few minutes. Two different absorption peaks attributed to Br2 • - and Br3 - were observed simultaneously in NaBr aqueous solutions, showing powerfulness of the measurement system in overviewing chemical kinetics under ion beam irradiation especially in not well investigated chemical systems.

  13. Accurate calculation of the x-ray absorption spectrum of water via the GW/Bethe-Salpeter equation

    NASA Astrophysics Data System (ADS)

    Gilmore, Keith; Vinson, John; Kas, Josh; Vila, Fernando; Rehr, John

    2014-03-01

    We calculate x-ray absorption spectra (XAS) of water within the OCEAN code, which combines plane-wave, pseudopotential electronic structure, PAW transition elements, GW self-energy corrections, and the NIST BSE solver. Due to the computational demands of this approach, our initial XAS calculations were limited to 17 molecule super cells. This lead to unphysical, size dependent effects in the calculated spectra. To treat larger systems, we extended the OCEAN interface to support well-parallelized codes such as QuantumESPRESSO. We also implemented an efficient interpolation scheme of Shirley. We applied this large-scale GW/BSE approach to 64 molecule unit cell structures of water obtained from classical DFT/MD and PIMD simulations. In concurrence with previous work, we find the calculated spectrum both qualitatively and quantitatively reproduces the experimental features. The agreement implies that structures based on PIMD, which are similar to the traditional distorted tetrahedral view, are consistent with experimental observations. Supported by the DOE CMCSN through DOE award DE-SC0005180 (Princeton University) and in part by DOE Grant No. DE-FG03-97ER45623 (JJR) with computer support from NERSC.

  14. A Giant Metrewave Radio Telescope search for associated H I 21 cm absorption in high-redshift flat-spectrum sources

    NASA Astrophysics Data System (ADS)

    Aditya, J. N. H. S.; Kanekar, Nissim; Kurapati, Sushma

    2016-02-01

    We report results from a Giant Metrewave Radio Telescope search for `associated' redshifted H I 21 cm absorption from 24 active galactic nuclei (AGNs), at 1.1 < z < 3.6, selected from the Caltech-Jodrell Bank Flat-spectrum (CJF) sample. 22 out of 23 sources with usable data showed no evidence of absorption, with typical 3σ optical depth detection limits of ≈0.01 at a velocity resolution of ≈30 km s-1. A single tentative absorption detection was obtained at z ≈ 3.530 towards TXS 0604+728. If confirmed, this would be the highest redshift at which H I 21 cm absorption has ever been detected. Including 29 CJF sources with searches for redshifted H I 21 cm absorption in the literature, mostly at z < 1, we construct a sample of 52 uniformly selected flat-spectrum sources. A Peto-Prentice two-sample test for censored data finds (at ≈3σ significance) that the strength of H I 21 cm absorption is weaker in the high-z sample than in the low-z sample; this is the first statistically significant evidence for redshift evolution in the strength of H I 21 cm absorption in a uniformly selected AGN sample. However, the two-sample test also finds that the H I 21 cm absorption strength is higher in AGNs with low ultraviolet or radio luminosities, at ≈3.4σ significance. The fact that the higher luminosity AGNs of the sample typically lie at high redshifts implies that it is currently not possible to break the degeneracy between AGN luminosity and redshift evolution as the primary cause of the low H I 21 cm opacities in high-redshift, high-luminosity AGNs.

  15. Inertial solvent dynamics and the analysis of spectral line shapes: Temperature-dependent absorption spectrum of beta-carotene in nonpolar solvent.

    PubMed

    Burt, Jim A; Zhao, Xihua; McHale, Jeanne L

    2004-03-01

    The influence of solvent dynamics on optical spectra is often described by a stochastic model which assumes exponential relaxation of the time-correlation function for solvent-induced frequency fluctuations. In contrast, theory and experiment suggest that the initial (subpicosecond) phase of solvent relaxation, resulting from inertial motion of the solvent, is a Gaussian function of time. In this work, we employ numerical and analytical calculations to compare the predicted absorption line shapes and the derived solvent reorganization energies obtained from exponential (Brownian oscillator) versus Gaussian (inertial) solvent dynamics. Both models predict motional narrowing as the ratio kappa = Lambda/Delta is increased, where Lambda and Delta are the frequency and variance, respectively, of the solvent-induced frequency fluctuations. However, the motional narrowing limit is achieved at lower values of kappa for the Brownian oscillator model compared to the inertial model. For a given line shape, the derived value of the solvent reorganization energy lambdasolv is only weakly dependent on the solvent relaxation model employed, though different solvent parameters Lambda and Delta are obtained. The two models are applied to the analysis of the temperature-dependent absorption spectrum of beta-carotene in isopentane and CS2. The derived values of lambdasolv using the Gaussian model are found to be in better agreement with the high temperature limit of Delta2/2kBT than are the values obtained using the Brownian oscillator model. In either approach, the solvent reorganization energy is found to increase slightly with temperature as a result of an increase in the variance Delta of the solvent-induced frequency fluctuations. PMID:15268604

  16. Inertial solvent dynamics and the analysis of spectral line shapes: Temperature-dependent absorption spectrum of β-carotene in nonpolar solvent

    NASA Astrophysics Data System (ADS)

    Burt, Jim A.; Zhao, Xihua; McHale, Jeanne L.

    2004-03-01

    The influence of solvent dynamics on optical spectra is often described by a stochastic model which assumes exponential relaxation of the time-correlation function for solvent-induced frequency fluctuations. In contrast, theory and experiment suggest that the initial (subpicosecond) phase of solvent relaxation, resulting from inertial motion of the solvent, is a Gaussian function of time. In this work, we employ numerical and analytical calculations to compare the predicted absorption line shapes and the derived solvent reorganization energies obtained from exponential (Brownian oscillator) versus Gaussian (inertial) solvent dynamics. Both models predict motional narrowing as the ratio κ=Λ/Δ is increased, where Λ and Δ are the frequency and variance, respectively, of the solvent-induced frequency fluctuations. However, the motional narrowing limit is achieved at lower values of κ for the Brownian oscillator model compared to the inertial model. For a given line shape, the derived value of the solvent reorganization energy λsolv is only weakly dependent on the solvent relaxation model employed, though different solvent parameters Λ and Δ are obtained. The two models are applied to the analysis of the temperature-dependent absorption spectrum of β-carotene in isopentane and CS2. The derived values of λsolv using the Gaussian model are found to be in better agreement with the high temperature limit of Δ2/2kBT than are the values obtained using the Brownian oscillator model. In either approach, the solvent reorganization energy is found to increase slightly with temperature as a result of an increase in the variance Δ of the solvent-induced frequency fluctuations.

  17. The absorption spectrum of the QSO PKS 2126-158 (z_em =3.27) at high resolution

    NASA Astrophysics Data System (ADS)

    D'Odorico, V.; Cristiani, S.; D'Odorico, S.; Fontana, A.; Giallongo, E.

    1998-01-01

    Spectra of the z_em = 3.268 quasar PKS 2126-158 have been obtained in the range lambda lambda 4300-6620 Angstroms with a resolution Rsmallimeq27000 and an average signal-to-noise ratio s/nsmallimeq 25 per resolution element. The list of the identified absorption lines is given together with their fitted column densities and Doppler widths. The modal value of the Doppler parameter distribution for the Lyalpha lines is smallimeq 25 km s(-1) . The column density distribution can be described by a power-law dn / dN ~ N(-beta ) with beta smallimeq 1.5. 12 metal systems have been identified, two of which were previously unknown. In order to make the column densities of the intervening systems compatible with realistic assumptions about the cloud sizes and the silicon to carbon overabundance, it is necessary to assume a jump beyond the He II edge in the spectrum of the UV ionizing background at z smallim 3 a factor 10 larger than the standard predictions for the integrated quasar contribution. An enlarged sample of C IV absorptions (71 doublets) has been used to analyze the statistical properties of this class of absorbers strictly related to galaxies. The column density distribution is well described by a single power-law, with beta =1.64 and the Doppler parameter distribution shows a modal value b_CIV smallimeq 14 km s(-1) . The two point correlation function has been computed in the velocity space for the individual components of C IV features. A significant signal is obtained for scales smaller than 200- 300 km s(-1) , xi (30< Delta v < 90 km\\ s(-1) ) = 33 +/- 3. A trend of decreasing clustering amplitude with decreasing column density is apparent, analogously to what has been observed for Lyalpha lines. Based on observations collected at the European Southern Observatory, La Silla, Chile (ESO No. 2-013-49K). Table 2 is only available in electronic from via anonymous ftp 130.79.128.5 or http://cdsweb.u-strasbg.fr/Abstract.html

  18. 5f3 --> 5f 26d1 absorption spectrum analysis of U3+-SrCl2.

    PubMed

    Karbowiak, Mirosław

    2005-04-28

    The 5f3--> 5f26d1 absorption spectra of the U3+ ions incorporated in SrCl2 single crystals were recorded at 4.2 K in the 15,000-50,000 cm(-1) spectral range. From an analysis of the vibronic structure, 32 zero-phonon lines corresponding to transitions from the 4I9/2 ground multiplet of the 5f3 configuration to the 5f26d(eg)1 excited levels were assigned. A theoretical model proposed by Reid et al. (Reid, H. F.; van Pieterson, L.; Wegh, R. T.; Meijerink, A. Phys. Rev. B 2000, 62, 14744) that extends the established model for energy-level calculations of nf N states has been applied for analysis of the spectrum. The Fk(ff) (k = 2, 4), zeta(5f)(ff), B0(4)(ff), B0(6)(ff), Fk(fd) (k = 2, 4), and Gj(fd) (j = 1, 3) Hamiltonian parameters were determined by a least-squares fitting of the calculated energies to the experimental data. A good overall agreement between the calculated and experimentally observed energy levels has been achieved, with the root-mean-square (rms) deviation equal to 95 cm(-1) for 32 fitted levels and 9 varied parameters. Adjusted values of Fk(ff) and zeta(5f)(ff) parameters for the 5f2 core electrons are closer to the values characteristic of the 5f2 (U4+) configuration than to those of the 5f3 (U3+) configuration. For the U3+ ion, the f-d Coulomb interaction parameters are significantly more reduced from the values calculated using Cowan's computer code than they are for lanthanide ions. Moreover, because of weaker f-d Coulomb interactions for the U3+ ion than for the isoelectronic Nd3+ lanthanide ion, the very simple model assuming the coupling of crystal-field levels of the 6d1 electron with the lattice and the multiplet structure of the 5f2 configuration may be employed for the qualitative description of the general structure of the U3+ ion f-d spectrum. PMID:16839023

  19. Communication: Does a single CH{sub 3}CN molecule attached to Ru(bipy){sub 3}{sup 2+} affect its absorption spectrum?

    SciTech Connect

    Stockett, M. H.; Brøndsted Nielsen, S.

    2015-05-07

    Tris(bipyridine)ruthenium(II) (Ru(bipy){sub 3}{sup 2+}) is a prototypical transition metal coordination complex whose photophysical properties have attracted considerable attention. A much debated issue is whether the metal-to-ligand charge transfer (MLCT) transition that accounts for the complex’s beautiful red color is fully delocalized across all three bipyridine ligands or located on just one ligand. Here, we show based on gas-phase action spectroscopy that attachment of a single acetonitrile molecule does not change the absorption spectrum from that of the bare ions, which is indicative of a delocalized state. However, the gas-phase spectra of the bare and one solvent molecule complexes are significantly blueshifted relative to that obtained in bulk acetonitrile, which suggests that in solution the polarizability of many solvent molecules working together can localize the MLCT state. Our data clearly show that more than one solvent molecule is needed to break the symmetry of the MLCT excited state and reproduce its solution-phase characteristics.

  20. A New Search for Carbon Monoxide Absorption in the Transmission Spectrum of the Extrasolar Planet HD 209458b

    NASA Astrophysics Data System (ADS)

    Deming, Drake; Brown, Timothy M.; Charbonneau, David; Harrington, Joseph; Richardson, L. Jeremy

    2005-04-01

    We have revisited the search for carbon monoxide absorption features in transmission during the transit of the extrasolar planet HD 209458b. In 2002 August-September we acquired a total of 1077 high-resolution spectra (λ/δλ~25,000) in the K-band (2 μm) wavelength region using NIRSPEC on the Keck II telescope during three transits. These data are more numerous and of better quality than the data analyzed in an initial search by Brown et al. Our analysis achieves a sensitivity sufficient to test the degree of CO absorption in the first-overtone bands during transit on the basis of plausible models of the planetary atmosphere. We analyze our observations by comparison with theoretical tangent geometry absorption spectra, computed by adding height-invariant ad hoc temperature perturbations to the model atmosphere of Sudarsky et al. and by treating cloud height as an adjustable parameter. We do not detect CO absorption. The strong 2-0 R-branch lines between 4320 and 4330 cm-1 have depths during transit less than 1.6 parts in 104 in units of the stellar continuum (3 σ limit) at a spectral resolving power of 25,000. Our analysis indicates a weakening similar to that found in the case of sodium, suggesting that a general masking mechanism is at work in the planetary atmosphere. Under the interpretation that this masking is provided by high clouds, our analysis defines the maximum cloud-top pressure (i.e., minimum height) as a function of the model atmospheric temperature. For the relatively hot model used by Charbonneau et al. to interpret their sodium detection, our CO limit requires cloud tops at or above 3.3 mbar, and these clouds must be opaque at a wavelength of 2 μm. High clouds comprised of submicron-sized particles are already present in some models but may not provide sufficient opacity to account for our CO result. Cooler model atmospheres, having smaller atmospheric scale heights and lower CO mixing ratios, may alleviate this problem to some extent

  1. Solvent effects on the absorption spectrum and first hyperpolarizability of keto-enol tautomeric forms of anil derivatives: A Monte Carlo/quantum mechanics study

    NASA Astrophysics Data System (ADS)

    Adriano Junior, L.; Fonseca, T. L.; Castro, M. A.

    2016-06-01

    Theoretical results for the absorption spectrum and electric properties of the enol and keto tautomeric forms of anil derivatives in the gas-phase and in solution are presented. The electronic properties in chloroform, acetonitrile, methanol, and water were determined by carrying out sequential Monte Carlo simulations and quantum mechanics calculations based on the time dependent density functional theory and on the second-order Møller-Plesset perturbation theory method. The results illustrate the role played by electrostatic interactions in the electronic properties of anil derivatives in a liquid environment. There is a significant increase of the dipole moment in solution (20%-100%) relative to the gas-phase value. Solvent effects are mild for the absorption spectrum and linear polarizability but they can be particularly important for first hyperpolarizability. A large first hyperpolarizability contrast between the enol and keto forms is observed when absorption spectra present intense lowest-energy absorption bands. Dynamic results for the first hyperpolarizability are in qualitative agreement with the available experimental results.

  2. Solvent effects on the absorption spectrum and first hyperpolarizability of keto-enol tautomeric forms of anil derivatives: A Monte Carlo/quantum mechanics study.

    PubMed

    Adriano Junior, L; Fonseca, T L; Castro, M A

    2016-06-21

    Theoretical results for the absorption spectrum and electric properties of the enol and keto tautomeric forms of anil derivatives in the gas-phase and in solution are presented. The electronic properties in chloroform, acetonitrile, methanol, and water were determined by carrying out sequential Monte Carlo simulations and quantum mechanics calculations based on the time dependent density functional theory and on the second-order Møller-Plesset perturbation theory method. The results illustrate the role played by electrostatic interactions in the electronic properties of anil derivatives in a liquid environment. There is a significant increase of the dipole moment in solution (20%-100%) relative to the gas-phase value. Solvent effects are mild for the absorption spectrum and linear polarizability but they can be particularly important for first hyperpolarizability. A large first hyperpolarizability contrast between the enol and keto forms is observed when absorption spectra present intense lowest-energy absorption bands. Dynamic results for the first hyperpolarizability are in qualitative agreement with the available experimental results. PMID:27334183

  3. The effect of deformation and intermolecular interaction on the absorption spectrum of 5-aminotetrazole and hydrazine: A computational molecular spectroscopy study on hydrazinium 5-aminotetrazolate

    NASA Astrophysics Data System (ADS)

    Farrokhpour, H.; Dehbozorgi, A.; Manassir, M.; Najafi Chermahini, A.

    2016-03-01

    In the present work, the UV absorption spectra of seven complexes of hydrazinium 5-aminotetrazolate (HY-5AT), in the range of 4-12 eV, were calculated in both gas and water. The UV absorption spectra of the selected HY-5AT complexes were also calculated in the absence of the intermolecular interaction between 5-aminotetrazole (5AT) and hydrazine (HY) and compared with the calculated UV absorption spectra of isolated HY and 5AT in the gas phase to see the effect of deformation on the electronic structures of the fragments. In addition, the calculated spectra of HY-5AT complexes were compared with the corresponding calculated spectra of HY-5AT complexes in the absence of the interaction between HY and 5AT to see the effect of interaction between two fragments on the absorption spectra of the complexes. Similar studies were performed on the most stable structure of HY-5AT complex in water and different trend was observed for the effect of deformation and interaction on the absorption spectrum of complex compared to the gas phase.

  4. The HD spectrum near 2.3 μm by CRDS-VECSEL: Electric quadrupole transition and collision-induced absorption

    NASA Astrophysics Data System (ADS)

    Vasilchenko, S.; Mondelain, D.; Kassi, S.; Čermák, P.; Chomet, B.; Garnache, A.; Denet, S.; Lecocq, V.; Campargue, A.

    2016-08-01

    The HD absorption spectrum is investigated near 2.3 μm with the help of a newly developed Cavity Ring Down Spectrometer (CRDS) using a VECSEL (Vertical External Cavity Surface Emitting Laser) as light source. The HD CRDS spectra were recorded for a series of ten pressure values in the range 50-650 Torr. The sensitivity of the recordings - noise equivalent absorption of the spectra on the order of αmin ≈ 5 × 10-10 cm-1 - has allowed for the first detection of the S(3) quadrupole electric transition of the HD fundamental band, at 4359.940 cm-1. The line center determined with an uncertainty of 0.002 cm-1 agrees with the most recent theoretical calculations. The retrieved value of the line intensity (2.5 × 10-27 cm/molecule at 296 K) agrees within 12% with the ab initio values included in the HITRAN spectroscopic database. We take the opportunity of this contribution to provide an exhaustive review of seventy-three HD absorption lines previously detected up to 20,000 cm-1. From the pressure dependence of the baseline of the CRDS spectra, the binary absorption coefficient of the HD collision induced absorption band is determined to be 1.17(4) × 10-6 cm-1amagat-2 at 4360 cm-1.

  5. Preliminary Evidence Suggesting Caution in the Use of Psychiatric Self-Report Measures with Adolescents with High-Functioning Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Mazefsky, C. A.; Kao, J.; Oswald, D. P.

    2011-01-01

    This study investigated the utility of self-report measures to screen for psychiatric comorbidities in autism spectrum disorders (ASDs). Thirty-eight 10-17 year olds with an ASD and without mental retardation completed: the "Children's Depression Inventory-Short version (CDI-S)", "Revised Children's Manifest Anxiety Scale (RCMAS)", "Conners-Wells…

  6. The 13CH4 absorption spectrum in the Icosad range (6600-7692 cm-1) at 80 K and 296 K: Empirical line lists and temperature dependence

    NASA Astrophysics Data System (ADS)

    Campargue, A.; Béguier, S.; Zbiri, Y.; Mondelain, D.; Kassi, S.; Karlovets, E. V.; Nikitin, A. V.; Rey, M.; Starikova, E. N.; Tyuterev, Vl. G.

    2016-08-01

    The 13CH4 absorption spectrum has been recorded at 296 K and 80 K in the Icosad range between 6600 and 7700 cm-1. The achieved noise equivalent absorption of the spectra recorded by differential absorption spectroscopy (DAS) is about αmin ≈ 1.5 × 10-7 cm-1. Two empirical line lists were constructed including 17,792 and 24,139 lines at 80 K and 296 K, respectively. For comparison, the HITRAN database provides only 1040 13CH4 lines in the region determined from methane spectra with natural isotopic abundance. Empirical values of the lower state energy level, Eemp, were systematically derived from the intensity ratios of the lines measured at 80 K and 296 K. Overall 10,792 Eemp values were determined providing accurate temperature dependence for most of the 13CH4 absorption in the region (93% and 82% at 80 K and 296 K, respectively). The quality of the derived empirical values of the lower state rotational quantum number, Jemp, is illustrated by their clear propensity to be close to an integer. A good agreement is achieved between our small Jemp values, with previous accurate determinations obtained by applying the 2T method to jet and 80 K spectra. The line lists at 296 K and 80 K which are provided as Supplementary material will be used for future rovibrational assignments based on accurate variational calculations.

  7. Electronic Absorption Spectra from MM and ab initio QM/MM Molecular Dynamics: Environmental Effects on the Absorption Spectrum of Photoactive Yellow Protein

    PubMed Central

    Isborn, Christine M.; Götz, Andreas W.; Clark, Matthew A.; Walker, Ross C.; Martínez, Todd J.

    2012-01-01

    We describe a new interface of the GPU parallelized TeraChem electronic structure package and the Amber molecular dynamics package for quantum mechanical (QM) and mixed QM and molecular mechanical (MM) molecular dynamics simulations. This QM/MM interface is used for computation of the absorption spectra of the photoactive yellow protein (PYP) chromophore in vacuum, aqueous solution, and protein environments. The computed excitation energies of PYP require a very large QM region (hundreds of atoms) covalently bonded to the chromophore in order to achieve agreement with calculations that treat the entire protein quantum mechanically. We also show that 40 or more surrounding water molecules must be included in the QM region in order to obtain converged excitation energies of the solvated PYP chromophore. These results indicate that large QM regions (with hundreds of atoms) are a necessity in QM/MM calculations. PMID:23476156

  8. Gas cell based on optical contacting for fundamental spectroscopy studies with initial reference absorption spectrum of H2O vapor at 1723 K and 0.0235 bar

    NASA Astrophysics Data System (ADS)

    Melin, Scott T.; Sanders, Scott T.

    2016-09-01

    A gas cell, using optically contacted sapphire windows to form a hot vapor seal, has been created for high temperature fundamental spectroscopy studies. It is designed to operate at temperatures from 280-2273 K and pressures from vacuum to 1.3 bar. Using the cell in conjunction with an external cavity diode laser spectrometer, a reference H2O vapor absorption spectrum at P=0.0235±0.0036 bar and T=1723±6 K was measured with 0.0001 cm-1 resolution over the 7326-7598 cm-1 range. Comparison of the measured spectrum to simulations reveals errors in both the HITEMP and BT2 databases. This work establishes heated static cell capabilities at temperatures well above the typical limit of approximately 1300 K set by quartz material properties. This paper addresses the design of the cell as well as the cell's limitations.

  9. Rotationally resolved à 2Πg←X˜2Πu electronic spectrum of triacetylene cation by frequency modulation absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Sinclair, Wayne E.; Pfluger, David; Linnartz, Harold; Maier, John P.

    1999-01-01

    The spectrum of the à 2Πg←X˜2Πu 000 band system of the triacetylene cation and isotopic derivatives DC6H+ and C6D2+ have been studied at Doppler-limited resolution using frequency modulation absorption spectroscopy. The ions were generated in a liquid-nitrogen-cooled hollow cathode discharge incorporated in a White cell. A discharge modulation in combination with the frequency modulation technique was used to enhance the detection sensitivity. Analyses of the rotational structure yield accurate rotational and spin-orbit interaction constants of triacetylene cation in the two electronic states and information on its geometry.

  10. Contribution of a visual pigment absorption spectrum to a visual function: depth perception in a jumping spider

    PubMed Central

    Nagata, Takashi; Arikawa, Kentaro; Terakita, Akihisa

    2013-01-01

    Absorption spectra of visual pigments are adaptively tuned to optimize informational capacity in most visual systems. Our recent investigation of the eyes of the jumping spider reveals an apparent exception: the absorption characteristics of a visual pigment cause defocusing of the image, reducing visual acuity generally in a part of the retina. However, the amount of defocus can theoretically provide a quantitative indication of the distance of an object. Therefore, we proposed a novel mechanism for depth perception in jumping spiders based on image defocus. Behavioral experiments revealed that the depth perception of the spider depended on the wavelength of the ambient light, which affects the amount of defocus because of chromatic aberration of the lens. This wavelength effect on depth perception was in close agreement with theoretical predictions based on our hypothesis. These data strongly support the hypothesis that the depth perception mechanism of jumping spiders is based on image defocus.

  11. Diagnosing the reionization of the universe - The absorption spectrum of the intergalactic medium and Lyman alpha clouds

    NASA Technical Reports Server (NTRS)

    Giroux, Mark L.; Shapiro, Paul R.

    1991-01-01

    The thermal and ionization evolution of a uniform intergalactic medium composed of H and He and undergoing reionization is studied. The diagnosis of the metagalactic ionizing radiation background at z of about three using metal line ratios for Lyman limit quasar absorption line systems is addressed. The use of the He II Gunn-Peterson effect to diagnose the reionization source and/or nature of the Hy-alpha forest clouds is considered.

  12. Ultrafast transient absorption spectrum of the room temperature Ionic liquid 1-hexyl-3-methylimidazolium bromide: Confounding effects of photo-degradation

    NASA Astrophysics Data System (ADS)

    Musat, Raluca M.; Crowell, Robert A.; Polyanskiy, Dmitriy E.; Thomas, Marie F.; Wishart, James F.; Katsumura, Yosuke; Takahashi, Kenji

    2015-12-01

    The photochemistry of the charge transfer (CT) band of the room temperature ionic liquid (RTIL) 1-hexyl-3-methylimidazolium bromide (HMIm+/Br-) is investigated using near-IR to vis ultrafast transient absorption (TA) and steady-state UV absorption spectroscopies. Continuous irradiation of the CT band at 266 nm results in the formation of photo-products that absorb strongly at 266 nm. It is shown that these photo-products, which are apparently very stable, adversely affect ultrafast TA measurements. Elimination of these effects reveals at least two transient species that exist within the TA detection window of 100 fs to 3 ns and 500-1250 nm. One of the components is a short-lived (<1 ps) species that absorbs at 1080 nm. The second band exhibits a multicomponent spectrum that is very broad with an absorption maximum around 600 nm and a lifetime that is longer than the 3 ns window of our TA spectrometer. Within the signal to noise ratio of the TA spectrometer little to no solvated electron is generated by the CT mechanism.

  13. Low-temperature high-resolution absorption spectrum of 14NH3 in the ν1+ν3 band region (1.51 μm)

    NASA Astrophysics Data System (ADS)

    Földes, T.; Golebiowski, D.; Herman, M.; Softley, T. P.; Di Lonardo, G.; Fusina, L.

    2014-09-01

    Jet-cooled spectra of 14NH3 and 15NH3 in natural abundance were recorded using cavity ring-down (CRDS, 6584-6670 cm-1) and cavity enhanced absorption (CEAS, 6530-6700 cm-1) spectroscopy. Line broadening effects in the CRDS spectrum allowed lines with J″-values between 0 and 3 to be identified. Intensity ratios in 14NH3 between the jet-cooled CRDS and literature room-temperature data from Sung et al. (J. Quant. Spectrosc. Radiat. Transfer, 113 (2012), 1066) further assisted the line assignments. Ground state combination differences were extensively used to support the assignments, providing reliable values for J, K and inversion symmetry of the ground state vibrational levels. CEAS data helped in this respect for the lowest J lines, some of which are saturated in the CRDS spectrum. Further information on a/s doublets arose from the observed spectral structures. Thirty-two transitions of 14NH3 were assigned in this way and a limited but significant number (19) of changes in the assignments results, compared to Sung et al. or to Cacciani et al. (J. Quant. Spectrosc. Radiat. Transfer, 113 (2012), 1084). Sixteen known and 25 new low-J transitions were identified for 15NH3 in the CRDS spectrum but the much scarcer literature information did not allow for any more refined assignment. The present line position measurements improve on literature values published for 15NH3 and on some line positions for 14NH3.

  14. VizieR Online Data Catalog: Absorption spectrum of the QSO PKS2126-158 (D'Odorico+ 1998)

    NASA Astrophysics Data System (ADS)

    D'Odorico, V.; Cristiani, S.; D'Odorico, S.; Fontana, A.; Giallongo, E.

    1997-10-01

    Spectra of the zem=3.268 quasar PKS 2126-158 have been obtai the wavelength range 430-662nm with a resolution R=27000 and an average signal to noise ratio s/n=25 per resolution element. 12 metal absorption systems have been identified, two of which were previously unknown. All the lines shortward of the Lymanα emission not identified as due to metals have been fitted as Lymanα and Lymanβ. We reported statistical analysis of this sample of lines. In particular, the two-point correlation function for metal systems has been computed. (1 data file).

  15. UV and VUV spectrum of matrix-isolated In: an investigation by absorption, magnetic circular dichroism and emission yield spectroscopy

    NASA Astrophysics Data System (ADS)

    Schroeder, W.; Rotermund, H.-H.; Wiggenhauser, H.; Schrittenlacher, W.; Hormes, J.; Krebs, W.; Laaser, W.

    1986-05-01

    The electronic absorption spectra of In atoms isolated in neon, argon, krypton and xenon matrices have been measured in the energy range between 2.5 and 9.0 eV. This region includes the 5s 25p → 5s 26s and 5s 25p → 5s 25d resonance transitions, higher members of the corresponding s- and d-Rydberg series and the inner shell 5s 25p → 5s5p 2 transitions. A correlation of the absorption spectra with results obtained from magnetic circular dichroism and fluorescence measurements has made it possible to provide a detailed assignment of most of the features in the spectra in spite of the complexities associated with their behavior. For example, the transition to 5s 26s could not be detected in any of the matrices and the 5s 25d configuration was found to be strongly quenched in intensity as compared to the other transitions. In contrast, several Rydberg transitions could be observed for In in Ne. These were satisfactorily interpreted within the Frenkel formalism. Some of these observations have been rationalized by assuming that the average radius of the wavefunction for the excited state is the dominant parameter for the matrix interaction.

  16. Spectral Similarity Assessment Based on a Spectrum Reflectance-Absorption Index and Simplified Curve Patterns for Hyperspectral Remote Sensing.

    PubMed

    Ma, Dan; Liu, Jun; Huang, Junyi; Li, Huali; Liu, Ping; Chen, Huijuan; Qian, Jing

    2016-01-01

    Hyperspectral images possess properties such as rich spectral information, narrow bandwidth, and large numbers of bands. Finding effective methods to retrieve land features from an image by using similarity assessment indices with specific spectral characteristics is an important research question. This paper reports a novel hyperspectral image similarity assessment index based on spectral curve patterns and a reflection-absorption index. First, some spectral reflection-absorption features are extracted to restrict the subsequent curve simplification. Then, the improved Douglas-Peucker algorithm is employed to simplify all spectral curves without setting the thresholds. Finally, the simplified curves with the feature points are matched, and the similarities among the spectral curves are calculated using the matched points. The Airborne Visible Infrared Imaging Spectrometer (AVIRIS) and Reflective Optics System Imaging Spectrometer (ROSIS) hyperspectral image datasets are then selected to test the effect of the proposed index. The practical experiments indicate that the proposed index can achieve higher precision and fewer points than the traditional spectral information divergence and spectral angle match. PMID:26821030

  17. Spectral Similarity Assessment Based on a Spectrum Reflectance-Absorption Index and Simplified Curve Patterns for Hyperspectral Remote Sensing

    PubMed Central

    Ma, Dan; Liu, Jun; Huang, Junyi; Li, Huali; Liu, Ping; Chen, Huijuan; Qian, Jing

    2016-01-01

    Hyperspectral images possess properties such as rich spectral information, narrow bandwidth, and large numbers of bands. Finding effective methods to retrieve land features from an image by using similarity assessment indices with specific spectral characteristics is an important research question. This paper reports a novel hyperspectral image similarity assessment index based on spectral curve patterns and a reflection-absorption index. First, some spectral reflection-absorption features are extracted to restrict the subsequent curve simplification. Then, the improved Douglas-Peucker algorithm is employed to simplify all spectral curves without setting the thresholds. Finally, the simplified curves with the feature points are matched, and the similarities among the spectral curves are calculated using the matched points. The Airborne Visible Infrared Imaging Spectrometer (AVIRIS) and Reflective Optics System Imaging Spectrometer (ROSIS) hyperspectral image datasets are then selected to test the effect of the proposed index. The practical experiments indicate that the proposed index can achieve higher precision and fewer points than the traditional spectral information divergence and spectral angle match. PMID:26821030

  18. Cl{sub 2}O photochemistry: Ultraviolet/vis absorption spectrum temperature dependence and O({sup 3}P) quantum yield at 193 and 248 nm

    SciTech Connect

    Papanastasiou, Dimitrios K.; Feierabend, Karl J.; Burkholder, James B.

    2011-05-28

    The photochemistry of Cl{sub 2}O (dichlorine monoxide) was studied using measurements of its UV/vis absorption spectrum temperature dependence and the O({sup 3}P) atom quantum yield, {Phi}{sub Cl{sub 2}O}{sup O}({lambda}), in its photolysis at 193 and 248 nm. The Cl{sub 2}O UV/vis absorption spectrum was measured over the temperature range 201-296 K between 200 and 500 nm using diode array spectroscopy. Cl{sub 2}O absorption cross sections, {sigma}{sub Cl{sub 2}O}({lambda},T), at temperatures <296 K were determined relative to its well established room temperature values. A wavelength and temperature dependent parameterization of the Cl{sub 2}O spectrum using the sum of six Gaussian functions, which empirically represent transitions from the ground {sup 1}A{sub 1} electronic state to excited states, is presented. The Gaussian functions are found to correlate well with published theoretically calculated vertical excitation energies. O({sup 3}P) quantum yields in the photolysis of Cl{sub 2}O at 193 and 248 nm were measured using pulsed laser photolysis combined with atomic resonance fluorescence detection of O({sup 3}P) atoms. O({sup 3}P) quantum yields were measured to be 0.85 {+-} 0.15 for 193 nm photolysis at 296 K and 0.20 {+-} 0.03 at 248 nm, which was also found to be independent of temperature (220-352 K) and pressure (17 and 28 Torr, N{sub 2}). The quoted uncertainties are at the 2{sigma} (95% confidence) level and include estimated systematic errors. ClO radical temporal profiles obtained following the photolysis of Cl{sub 2}O at 248 nm, as reported previously in Feierabend et al.[J. Phys. Chem. A 114, 12052, (2010)], were interpreted to establish a <5% upper-limit for the O + Cl{sub 2} photodissociation channel, which indicates that O({sup 3}P) is primarily formed in the three-body, O + 2Cl, photodissociation channel at 248 nm. The analysis also indirectly provided a Cl atom quantum yield of 1.2 {+-} 0.1 at 248 nm. The results from this work are compared

  19. FE K EMISSION AND ABSORPTION FEATURES IN THE XMM-EPIC SPECTRUM OF THE SEYFERT GALAXY IC 4329A

    NASA Technical Reports Server (NTRS)

    Markowitz, A.; Reeves, J. N.; Braito, V.

    2001-01-01

    We present a re-analysis of the XMM-Newton long-look of the X-ray bright Seyfert galaxy IC 4329a. The Fe K bandpass is dominated by two peaks, consistent with emission from neutral or near-neutral Fe Ka and KP. A relativistic diskline model whereby both peaks are the result of one doubly-peaked diskline profile is found to be a poor description of the data. Models using two relativistic disklines are found to describe the emission profile well. A low-inclination, moderately-relativistic dual-diskline model is possible if the contribution from narrow components, due to distant material, is small or absent. A high-inclination, moderately relativistic profile for each peak is possible if there are roughly equal contributions from both the broad and narrow components. Upper limits on Fe XXV and Fe XXVI emission and absorption at the systemic velocity of IC 4329a are obtained. We also present the results of RXTE monitoring of this source obtained so far; the combined XMM-Newton and RXTE data sets allow us to explore the time-resolved spectral behavior of this source on time scales ranging from hours to 2 years. We find no strong evidence for variability of the Fe Ka emission line on any time scale probed, likely due to the minimal level of continuum variability. We detect a narrow absorption line, at a energy of 7.68 keV in the rest frame of the source; its significance has been confirmed using Monte Carlo simulations. This feature is most likely due to absorption from Fe XXVI blueshifted to approximately 0.1c relative to the systemic velocity, making IC 4329a the lowest-redshift AGN known with a high-velocity, highly-ionized outflow component. As is often the case with similar outflows seen in high-luminosity quasars, the estimated mass outflow rate is larger than the inflow accretion rate, signaling that the outflow represents a substantial portion of the total energy budget of the AGN. The outflow could arise from a radiatively-driven disk wind, or it may be in the

  20. Discovery of a cyclotron absorption line in the spectrum of the binary X-ray pulsar 4U 1538 - 52 observed by Ginga

    NASA Technical Reports Server (NTRS)

    Clark, George W.; Woo, Jonathan W.; Nagase, Fumiaki; Makishima, Kazuo; Sakao, Taro

    1990-01-01

    A cyclotron absorption line near 20 keV has been found in the spectrum of the massive eclipsing binary X-ray pulsar 4U 1538 - 52 in observations with the Ginga observatory. The line is detected throughout the 529 s pulse cycle with a variable equivalent width that has its maximum value during the smaller peak of the two-peak pulse profile. It is found that the profile of the pulse and the phase-dependence of the cyclotron line can be explained qualitatively by a pulsar model based on recent theoretical results on the properties of pencil beams emitted by accretion-heated slabs of magnetized plasma at the magnetic poles of a neutron star. The indicated field at the surface of the neutron star is 1.7 (1 + z) x 10 to the 12th G, where z is the gravitational redshift.

  1. The 5 f r arrow 6 d absorption spectrum of Pa sup 4+ /Cs sub 2 ZrCl sub 6

    SciTech Connect

    Edelstein, N.; Kot, W.K. ); Krupa, J. )

    1992-01-01

    The 5{ital f}{sup 1}{r arrow}6{ital d}{sup 1} absorption spectrum of {sup 231}Pa{sup 4+} diluted in a single crystal of Cs{sub 2}ZrCl{sub 6} has been measured at 4.2 K. Three bands corresponding to the 6{ital d}({Gamma}{sub 8{ital g}}, {Gamma}{sub 7{ital g}}, and {Gamma}{sup {prime}}{sub 8{ital g}} ) levels are assigned. Extensive vibronic structure has been observed for the lowest 5{ital f}{r arrow}6{ital d} transition and this structure is compared to that recently reported for the 6{ital d}{sup 1}{r arrow}5{ital f}{sup 1} emission spectra in the same system.

  2. A full-dimensional multilayer multiconfiguration time-dependent Hartree study on the ultraviolet absorption spectrum of formaldehyde oxide.

    PubMed

    Meng, Qingyong; Meyer, Hans-Dieter

    2014-09-28

    Employing the multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) method in conjunction with the multistate multimode vibronic coupling Hamiltonian (MMVCH) model, we perform a full dimensional (9D) quantum dynamical study on the simplest Criegee intermediate, formaldehyde oxide, in five lower-lying singlet electronic states. The ultraviolet (UV) spectrum is then simulated by a Fourier transform of the auto-correlation function. The MMVCH model is built based on extensive MRCI(8e,8o)/aug-cc-pVTZ calculations. To ensure a fast convergence of the final calculations, a large number of ML-MCTDH test calculations is performed to find an appropriate multilayer separations (ML-trees) of the ML-MCTDH nuclear wave functions, and the dynamical calculations are carefully checked to ensure that the calculations are well converged. To compare the computational efficiency, standard MCTDH simulations using the same Hamiltonian are also performed. A comparison of the MCTDH and ML-MCTDH calculations shows that even for the present not-too-large system (9D here) the ML-MCTDH calculations can save a considerable amount of computational resources while producing identical spectra as the MCTDH calculations. Furthermore, the present theoretical B̃(1)A'←X̃(1)A' UV spectral band and the corresponding experimental measurements [J. M. Beames, F. Liu, L. Lu, and M. I. Lester, J. Am. Chem. Soc. 134, 20045-20048 (2012); L. Sheps, J. Phys. Chem. Lett. 4, 4201-4205 (2013); W.-L. Ting, Y.-H. Chen, W. Chao, M. C. Smith, and J. J.-M. Lin, Phys. Chem. Chem. Phys. 16, 10438-10443 (2014)] are discussed. To the best of our knowledge, this is the first theoretical UV spectrum simulated for this molecule including nuclear motion beyond an adiabatic harmonic approximation. PMID:25273439

  3. A full-dimensional multilayer multiconfiguration time-dependent Hartree study on the ultraviolet absorption spectrum of formaldehyde oxide

    NASA Astrophysics Data System (ADS)

    Meng, Qingyong; Meyer, Hans-Dieter

    2014-09-01

    Employing the multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) method in conjunction with the multistate multimode vibronic coupling Hamiltonian (MMVCH) model, we perform a full dimensional (9D) quantum dynamical study on the simplest Criegee intermediate, formaldehyde oxide, in five lower-lying singlet electronic states. The ultraviolet (UV) spectrum is then simulated by a Fourier transform of the auto-correlation function. The MMVCH model is built based on extensive MRCI(8e,8o)/aug-cc-pVTZ calculations. To ensure a fast convergence of the final calculations, a large number of ML-MCTDH test calculations is performed to find an appropriate multilayer separations (ML-trees) of the ML-MCTDH nuclear wave functions, and the dynamical calculations are carefully checked to ensure that the calculations are well converged. To compare the computational efficiency, standard MCTDH simulations using the same Hamiltonian are also performed. A comparison of the MCTDH and ML-MCTDH calculations shows that even for the present not-too-large system (9D here) the ML-MCTDH calculations can save a considerable amount of computational resources while producing identical spectra as the MCTDH calculations. Furthermore, the present theoretical tilde{B}{}^1A^' }leftarrow tilde{X}{}^1A^' } UV spectral band and the corresponding experimental measurements [J. M. Beames, F. Liu, L. Lu, and M. I. Lester, J. Am. Chem. Soc. 134, 20045-20048 (2012); L. Sheps, J. Phys. Chem. Lett. 4, 4201-4205 (2013); W.-L. Ting, Y.-H. Chen, W. Chao, M. C. Smith, and J. J.-M. Lin, Phys. Chem. Chem. Phys. 16, 10438-10443 (2014)] are discussed. To the best of our knowledge, this is the first theoretical UV spectrum simulated for this molecule including nuclear motion beyond an adiabatic harmonic approximation.

  4. A full-dimensional multilayer multiconfiguration time-dependent Hartree study on the ultraviolet absorption spectrum of formaldehyde oxide

    SciTech Connect

    Meng, Qingyong; Meyer, Hans-Dieter

    2014-09-28

    Employing the multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) method in conjunction with the multistate multimode vibronic coupling Hamiltonian (MMVCH) model, we perform a full dimensional (9D) quantum dynamical study on the simplest Criegee intermediate, formaldehyde oxide, in five lower-lying singlet electronic states. The ultraviolet (UV) spectrum is then simulated by a Fourier transform of the auto-correlation function. The MMVCH model is built based on extensive MRCI(8e,8o)/aug-cc-pVTZ calculations. To ensure a fast convergence of the final calculations, a large number of ML-MCTDH test calculations is performed to find an appropriate multilayer separations (ML-trees) of the ML-MCTDH nuclear wave functions, and the dynamical calculations are carefully checked to ensure that the calculations are well converged. To compare the computational efficiency, standard MCTDH simulations using the same Hamiltonian are also performed. A comparison of the MCTDH and ML-MCTDH calculations shows that even for the present not-too-large system (9D here) the ML-MCTDH calculations can save a considerable amount of computational resources while producing identical spectra as the MCTDH calculations. Furthermore, the present theoretical B{sup ~} {sup 1}A{sup ′}←X{sup ~} {sup 1}A{sup ′} UV spectral band and the corresponding experimental measurements [J. M. Beames, F. Liu, L. Lu, and M. I. Lester, J. Am. Chem. Soc. 134, 20045–20048 (2012); L. Sheps, J. Phys. Chem. Lett. 4, 4201–4205 (2013); W.-L. Ting, Y.-H. Chen, W. Chao, M. C. Smith, and J. J.-M. Lin, Phys. Chem. Chem. Phys. 16, 10438–10443 (2014)] are discussed. To the best of our knowledge, this is the first theoretical UV spectrum simulated for this molecule including nuclear motion beyond an adiabatic harmonic approximation.

  5. AN Fe XXIV ABSORPTION LINE IN THE PERSISTENT SPECTRUM OF THE DIPPING LOW-MASS X-RAY BINARY 1A 1744-361

    SciTech Connect

    Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

    2012-07-01

    We report on Chandra X-ray Observatory (Chandra) High Energy Transmission Grating spectra of the dipping low-mass X-ray binary 1A 1744-361 during its 2008 July outburst. We find that its persistent emission is well modeled by a blackbody (kT {approx} 1.0 keV) plus power law ({Gamma} {approx} 1.7) with an absorption edge. In the residuals of the combined spectrum, we find a significant absorption line at 6.961 {+-} 0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2-1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km s{sup -1}. We find an equivalent width for the line of 27{sup +2}{sub -3} eV, from which we determine a column density of (7 {+-} 1) Multiplication-Sign 10{sup 17} cm{sup -2} via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of >10{sup 3.6} erg cm s{sup -1}. We discuss what implications the feature has on the system and its geometry. We also present Rossi X-ray Timing Explorer data accumulated during this latest outburst and, via an updated color-color diagram, clearly show that 1A 1744-361 is an 'atoll' source.

  6. Assignment and modeling of the absorption spectrum of 13CH4 at 80 K in the region of the 2ν3 band (5853-6201 cm-1)

    NASA Astrophysics Data System (ADS)

    Starikova, E.; Nikitin, A. V.; Rey, M.; Tashkun, S. A.; Mondelain, D.; Kassi, S.; Campargue, A.; Tyuterev, Vl. G.

    2016-07-01

    The absorption spectrum of the 13CH4 methane isotopologue has been recently recorded by Differential Absorption Spectroscopy (DAS) at 80 K in the 5853-6201 cm-1 spectral range. An empirical list of 3717 lines was constructed for this spectral range corresponding to the upper part of the Tetradecad dominated by the 2ν3 band near 5987 cm-1. In this work, we present rovibrational analyses of these spectra obtained via two theoretical approaches. Assignments of strong and medium lines were achieved with variational calculations using ab initio potential energy (PES) and dipole moment surfaces. For further analysis a non-empirical effective Hamiltonian (EH) of the methane polyads constructed by high-order Contact Transformations (CT) from an ab initio PES was employed. Initially predicted values of EH parameters were empirically optimized using 2898 assigned line positions fitted with an rms deviation of 5×10-3 cm-1. More than 1860 measured line intensities were modeled using the effective dipole transition moments approach with the rms deviation of about 10%. These new data were used for the simultaneous fit of the 13CH4 Hamiltonian parameters of the {Ground state/Dyad/Pentad/Octad/Tetradecad} system and the dipole moment parameters of the {Ground state-Tetradecad} system. Overall, 10 vibrational states and 28 vibration sublevels of the 13CH4 Tetradecad are determined. The comparison of their energy values with corresponding theoretical calculations is discussed.

  7. An Fe XXIV Absorption Line in the Persistent Spectrum of the Dipping Low-Mass X-Ray Binary 1A 1744-361

    NASA Technical Reports Server (NTRS)

    Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

    2012-01-01

    We report on Chandra X-ray Observatory (Chandra) High Energy Transmission Grating spectra of the dipping low-mass X-ray binary 1A 1744-361 during its 2008 July outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power law (Gamma approx. 1.7) with an absorption edge. In the residuals of the combined spectrum, we find a significant absorption line at 6.961 +/- 0.002 keV, consistent with the Fe xxvi (hydrogen-like Fe) 2-1 transition.We place an upper limit on the velocity of a redshifted flow of nu < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of (7 +/- 1)×10(exp 17) /sq. cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of >103.6 erg cm/s. We discuss what implications the feature has on the system and its geometry. We also present Rossi X-ray Timing Explorer data accumulated during this latest outburst and, via an updated color-color diagram, clearly show that 1A 1744-361 is an "atoll" source

  8. A Combination of Chemometrics and Quantum Mechanics Methods Applied to Analysis of Femtosecond Transient Absorption Spectrum of Ortho-Nitroaniline

    PubMed Central

    Yi, Jing; Xiong, Ying; Cheng, Kemei; Li, Menglong; Chu, Genbai; Pu, Xuemei; Xu, Tao

    2016-01-01

    A combination of the advanced chemometrics method with quantum mechanics calculation was for the first time applied to explore a facile yet efficient analysis strategy to thoroughly resolve femtosecond transient absorption spectroscopy of ortho-nitroaniline (ONA), served as a model compound of important nitroaromatics and explosives. The result revealed that the ONA molecule is primarily excited to S3 excited state from the ground state and then ultrafast relaxes to S2 state. The internal conversion from S2 to S1 occurs within 0.9 ps. One intermediate state S* was identified in the intersystem crossing (ISC) process, which is different from the specific upper triplet receiver state proposed in some other nitroaromatics systems. The S1 state decays to the S* one within 6.4 ps and then intersystem crossing to the lowest triplet state within 19.6 ps. T1 was estimated to have a lifetime up to 2 ns. The relatively long S* state and very long-lived T1 one should play a vital role as precursors to various nitroaromatic and explosive photoproducts. PMID:26781083

  9. A Combination of Chemometrics and Quantum Mechanics Methods Applied to Analysis of Femtosecond Transient Absorption Spectrum of Ortho-Nitroaniline.

    PubMed

    Yi, Jing; Xiong, Ying; Cheng, Kemei; Li, Menglong; Chu, Genbai; Pu, Xuemei; Xu, Tao

    2016-01-01

    A combination of the advanced chemometrics method with quantum mechanics calculation was for the first time applied to explore a facile yet efficient analysis strategy to thoroughly resolve femtosecond transient absorption spectroscopy of ortho-nitroaniline (ONA), served as a model compound of important nitroaromatics and explosives. The result revealed that the ONA molecule is primarily excited to S3 excited state from the ground state and then ultrafast relaxes to S2 state. The internal conversion from S2 to S1 occurs within 0.9 ps. One intermediate state S* was identified in the intersystem crossing (ISC) process, which is different from the specific upper triplet receiver state proposed in some other nitroaromatics systems. The S1 state decays to the S* one within 6.4 ps and then intersystem crossing to the lowest triplet state within 19.6 ps. T1 was estimated to have a lifetime up to 2 ns. The relatively long S* state and very long-lived T1 one should play a vital role as precursors to various nitroaromatic and explosive photoproducts. PMID:26781083

  10. Electromagnetic resonance modes on a two-dimensional tandem grating and its application for broadband absorption in the visible spectrum.

    PubMed

    Han, Sunwoo; Lee, Bong Jae

    2016-01-25

    In this work, we numerically investigate the electromagnetic resonances on two-dimensional tandem grating structures. The base of a tandem grating consists of an opaque Au substrate, a SiO(2) spacer, and a Au grating (concave type); that is, a well-known fishnet structure forming Au/SiO(2)/Au stack. A convex-type Au grating (i.e., topmost grating) is then attached on top of the base fishnet structure with or without additional SiO(2) spacer, resulting in two types of tandem grating structures. In order to calculate the spectral reflectance and local magnetic field distribution, the finite-difference time-domain method is employed. When the topmost Au grating is directly added onto the base fishnet structure, the surface plasmon and magnetic polariton in the base structure are branched out due to the geometric asymmetry with respect to the SiO(2) spacer. If additional SiO(2) spacer is added between the topmost Au grating and the base fishnet structure, new magnetic resonance modes appear due to coupling between two vertically aligned Au/SiO(2)/Au stacks. With the understanding of multiple electromagnetic resonance modes on the proposed tandem grating structures, we successfully design a broadband absorber made of Au and SiO(2) in the visible spectrum. PMID:26832574

  11. High-resolution absorption spectrum of jet-cooled CH3Cl between 70 000 and 85 000 cm-1: New assignments

    NASA Astrophysics Data System (ADS)

    Cossart-Magos, Claudina; Jungen, Martin; Stalder, Joerg; Launay, Françoise

    2005-09-01

    The absorption spectrum of jet-cooled CH3Cl was photographed from 165to117nm (or 60000-85000cm-1, 7.5-10.5eV) at a resolution limit of 0.0008nm (0.3-0.6cm-1 or 0.04-0.08meV). Even in the best structured region of the spectrum, from 70000to85000cm-1 (8.7-10.5eV ), observed bandwidths (full width at half maximum) are large, from 50to150cm-1. No rotational feature could be resolved. The spectrum is dominated by two strong bands near 9eV, 140nm, the D and E bands of Mulliken [J. Chem. Phys. 8, 382 (1940)] or the spectral region D of Price [J. Chem. Phys.4, 539 (1936)]. Their relative intensity is incompatible with previous assignments, namely, to a triplet and a singlet state belonging to the same configuration. On the basis of the present ab initio calculations, those bands are now assigned to two singlet states, the A11 and E1 excited states resulting from the 2e34pe Rydberg configuration. The present calculations also reveal that the two E1 states issued from 2e34sa1 and 2e34pa1 are quasidegenerate and strongly mixed. They should be assigned to the two broad bands near 8eV, 160nm, the B and C bands of Mulliken and Price. Three vibrational modes are observed to be active: the CCl bond stretch ν3(a1), and the CH3 umbrella and rocking vibrations, respectively, ν2(a1) and ν6(e ). The fundamental frequencies deduced are well within the ranges defined by the corresponding values in the neutral and ion ground states. The possibility of a dynamical Jahn-Teller effect induced by the ν6(e) vibrational mode in the E1 Rydberg states is discussed.

  12. Infrared absorption spectrum of free carriers in polar semiconductors. Progress report, July 1, 1979-June 30, 1980

    SciTech Connect

    Jensen, B.

    1980-02-01

    The Drude Zener theory of the absorption of high frequency radiation by free carriers (inverse bremsstrahlung) has been extended into the quantum region (h-bar omega > k/sub 0/T) in terms of a frequency dependent relaxation time which predicts the dc mobility in the quasiclassical limit. Numerical calculations of the frequency and concentration dependent electron scattering rate have been completed for InP, InAs, Ga/sub 0/ /sub 47/In/sub 0/ /sub 53/As, and previous results for GaAs extended to high carrier concentrations. When starting from a quantum statistical theory, the fact that n/sub q/oh-bar omega ..-->.. k/sub 0/T at low frequencies can be used to prevent the divergence of the coulomb scattering rate without inclusion of a screening radius. A result containing no adjustable parameters is found which predicts a mobility for uncompensated samples that decreases strongly at high concentrations. This has been observed in GaAs, and is not accounted for by the usual dc calculation which assumes h-bar omega = 0 and a screening parameter. Calculated results for GaAs are in good agreement with experimental measurements of the mobility which are found to be independent of a wide variety of conditions of material preparation. This indicates that disagreement with previous theoretical calculations was not due to compensation. Calculations for ZnSe and further investigation of the modification of the optical constants by the presence of an intense laser field and by a static magnetic field are currently planned.

  13. Theoretical analysis of the two-photon absorption spectrum of Tb3+ in Cs2NaTbCl6

    NASA Astrophysics Data System (ADS)

    Wang, Dianyuan; Ning, Lixin; Xia, Shangda; Tanner, Peter A.

    2003-05-01

    Eighteen selected two-photon absorption (TPA) transition line strengths with polarization angles theta = 0° and 45°, spanning several orders of magnitude, have been calculated for the Tb3+ ion in the cubic host Cs2NaTbCl6. The results are in reasonable agreement with experimental results in the literature. The calculation utilized the crystal field (CF) wavefunctions for the initial and final states of the 4f8 configuration, and utilized free ion or CF wavefunctions (with the corresponding energies) for 4f7 core states of the whole intermediate 4f7 5d configuration comprising 34 320 states. The intensities of certain transitions were found to be very sensitive to the inclusion of the CF interaction within the 4f7 core. In contrast to previous fourth- or third-order calculations of the TPA transition line strength of the strong transition (7F 6)A1g rightarrow (5D 4)A1g using pure Russell-Saunders (RS) wavefunctions for the |7F 6 rangle initial and langle5D 4 | final states, our second-order direct calculation shows that the admixed RS wavefunctions |[7F 6 ]rangle and langle[5D 4 ]| must be used to account for its high intensity. The effects of CF interactions within the 4f7 core, i.e. J-mixing and CF energy level splitting, upon the (7F 6)A1g rightarrow (5D 4)Eg TPA transition line strength have been separated, and the latter effect is shown to be more important for the transition investigated.

  14. ANOMALOUS DIFFUSE INTERSTELLAR BANDS IN THE SPECTRUM OF HERSCHEL 36. I. OBSERVATIONS OF ROTATIONALLY EXCITED CH AND CH{sup +} ABSORPTION AND STRONG, EXTENDED REDWARD WINGS ON SEVERAL DIBs

    SciTech Connect

    Dahlstrom, Julie; York, Donald G.; Welty, Daniel E.; Oka, Takeshi; Johnson, Sean; Jiang Zihao; Sherman, Reid; Hobbs, L. M.; Friedman, Scott D.; Sonnentrucker, Paule; Rachford, Brian L.; Snow, Theodore P.

    2013-08-10

    Anomalously broad diffuse interstellar bands (DIBs) at 5780.5, 5797.1, 6196.0, and 6613.6 A are found in absorption along the line of sight to Herschel 36, the star illuminating the bright Hourglass region of the H II region Messier 8. Interstellar absorption from excited CH{sup +} in the J = 1 level and from excited CH in the J = 3/2 level is also seen. To our knowledge, neither those excited molecular lines nor such strongly extended DIBs have previously been seen in absorption from interstellar gas. These unusual features appear to arise in a small region near Herschel 36 which contains most of the neutral interstellar material in the sight line. The CH{sup +} and CH in that region are radiatively excited by strong far-IR radiation from the adjacent infrared source Her 36 SE. Similarly, the broadening of the DIBs toward Herschel 36 may be due to radiative pumping of closely spaced high-J rotational levels of relatively small, polar carrier molecules. If this picture of excited rotational states for the DIB carriers is correct and applicable to most DIBs, the 2.7 K cosmic microwave background may set the minimum widths (about 0.35 A) of known DIBs, with molecular processes and/or local radiation fields producing the larger widths found for the broader DIBs. Despite the intense local UV radiation field within the cluster NGC 6530, no previously undetected DIBs stronger than 10 mA in equivalent width are found in the optical spectrum of Herschel 36, suggesting that neither dissociation nor ionization of the carriers of the known DIBs by this intense field creates new carriers with easily detectable DIB-like features. Possibly related profile anomalies for several other DIBs are noted.

  15. Simultaneous detection of the absorption spectrum and refractive index ratio with a spectrophotometer: monitoring contaminants in bioethanol

    NASA Astrophysics Data System (ADS)

    Kontturi, V.; Hyvärinen, S.; García, A.; Carmona, R.; Murzin, D. Yu; Mikkola, J.-P.; Peiponen, K.-E.

    2011-05-01

    The optical properties of a biofuel resulting from the fungi-treated lignocellulosic biomass in an ethanol matrix were studied. The matrix simulates the case that the bioethanol is contaminated by sugars, water and colour pigments that reduce the quality of the biofuel and compromise the combustion process. It is suggested that by applying a spectrophotometer only, it is possible to obtain valid information, i.e. the spectral features of the contaminants as well as the refractive index ratio of bioethanol. This allows for simultaneous purity and density detection of biomass-derived liquids or liquid biofuels, in comparison to a reference representing an ideal bioethanol (pure ethyl alcohol, ethanol of 99.5% purity (v/v)).

  16. Local Effects in the X-ray Absorption Spectrum of CaCl2, MgCl2, and NaCl Solutions

    SciTech Connect

    Kulik, H J; Correa Tedesco, A A; Schwegler, E; Prendergast, D; Galli, G

    2010-04-12

    Both first principles molecular dynamics and theoretical X-ray absorption spectroscopy have been used to investigate the aqueous solvation of cations in 0.5 M MgCl{sub 2}, CaCl{sub 2}, and NaCl solutions. We focus here on the species-specific effects that Mg{sup 2+}, Ca{sup 2+}, and Na{sup +}, have on the X-ray absorption spectrum of the respective solutions. For the divalent cations, we find that the hydrogen bonding characteristics of the more rigid magnesium first shell water molecules differ from those in the more flexible solvation shell surrounding calcium. In particular, the first solvation shell water molecules of calcium are accessible to forming acceptor hydrogen bonds, and this results in an enhancement of a post-edge peak near 540 eV. The absence of acceptor hydrogen bonds for magnesium first shell water molecules provides an explanation for the experimental and theoretical observation of a lack of enhancement at the post-main-edge peak. For the sodium monovalent cation we find that the broad tilt angle distribution results in a broadening of post-edge features, despite populations in donor-and-acceptor configurations consistent with calcium. We also present the re-averaged spectra of the MgCl{sub 2}, CaCl{sub 2}, and NaCl solutions and show that trends apparent with increasing concentration (0.5 M, 2.0 M, 4.0 M) are consistent with experiment. Finally, we examine more closely both the effect that cation coordination number has on the hydrogen bonding network and the relative perturbation strength of the cations on lone pair oxygen orbitals.

  17. An Fe XXVI Absorption Line in the Persistent Spectrum of the Dipping Low Mass X-ray Binary 1A 1744-361

    NASA Technical Reports Server (NTRS)

    Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

    2009-01-01

    We report on Chandra X-ray Observatory (CXO) High-Energy Transmission Grating (HETG) spectra of the dipping Low Mass X-ray Binary (LMXB) 1A 1744-361 during its July 2008 outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power-law (Gamma approx. 1.7) with an absorption edge at 7.6 keV. In the residuals of the combined spectrum we find a significant absorption line at 6.961+/-0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2 - 1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of 7+/-1 x 10(exp 17)/sq cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of > 10(exp 3.6) erg cm/s. The properties of this line are consistent with those observed in other dipping LMXBs. Using Rossi X-ray Timing Explorer (RXTE) data accumulated during this latest outburst we present an updated color-color diagram which clearly shows that IA 1744-361 is an "atoll" source. Finally, using additional dips found in the RXTE and CXO data we provide an updated orbital period estimate of 52+/-5 minutes.

  18. The enhancement of 21.2%-power conversion efficiency in polymer photovoltaic cells by using mixed Au nanoparticles with a wide absorption spectrum of 400 nm-1000 nm

    NASA Astrophysics Data System (ADS)

    Hao, Jing-Yu; Xu, Ying; Zhang, Yu-Pei; Chen, Shu-Fen; Li, Xing-Ao; Wang, Lian-Hui; Huang, Wei

    2015-04-01

    Au nanoparticles (NPs) mixed with a majority of bone-like, rod, and cube shapes and a minority of irregular spheres, which can generate a wide absorption spectrum of 400 nm-1000 nm and three localized surface plasmon resonance peaks, respectively, at 525, 575, and 775 nm, are introduced into the hole extraction layer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) to improve optical-to-electrical conversion performances in polymer photovoltaic cells. With the doping concentration of Au NPs optimized, the cell performance is significantly improved: the short-circuit current density and power conversion efficiency of the poly(3-hexylthiophene): [6,6]-phenyl-C60-butyric acid methyl ester cell are increased by 20.54% and 21.2%, reaching 11.15 mA·cm-2 and 4.23%. The variations of optical, electrical, and morphology with the incorporation of Au NPs in the cells are analyzed in detail, and our results demonstrate that the cell performance improvement can be attributed to a synergistic reaction, including: 1) both the localized surface plasmon resonance- and scattering-induced absorption enhancement of the active layer, 2) Au doping-induced hole transport/extraction ability enhancement, and 3) large interface roughness-induced efficient exciton dissociation and hole collection. Project supported by the National Basic Research Program of China (Grant Nos. 2015CB932202 and 2012CB933301), the National Natural Science Foundation of China (Grant Nos. 61274065, 51173081, 61136003, BZ2010043, 51372119, and 51172110), the Science Fund from the Ministry of Education of China (Grant No. IRT1148), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20113223110005), the Priority Academic Program Development of Jiangsu Provincial Higher Education Institutions (Grant No. YX03001), and the National Synergistic Innovation Center for Advanced Materials and the Synergetic Innovation Center for Organic Electronics and

  19. Hybrid Ab initio/EFP approach for calculating d-d absorption spectrum of hexaammineruthenium(II) ion in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Yurenev, P. V.; Scherbinin, A. V.; Stepanov, N. F.

    Ab initio quantum chemical strategies for quantitatively predicting the lowest (1Ag rarr 1T1g) vertical d-d excitation energy of hexaammineruthenium(II) ion in aqueous solution are discussed. The scalar-relativistic ECP/valence basis set on Ru atom developed by the Stuttgart group in a combination with the state-average CASSCF(d) approach, followed by multiconfigurational quasi-degenerate second-order perturbation theory (MCQDPT2) to account for differential correlation effects is proved to be an adequate tool to reproduce the experimental absorption spectrum of the complex for a variety of AO basis sets on ligand atoms. In addition, different ab initio methodologies are examined in order to predict the ground state geometry which is consistent with the follow-up excitation spectrum calculations. It is observed that the use of the optimized structures of a hypothetical gas-phase complex lead to substantial underestimation of excitation energies. Solvent effects strongly influence the excitation energy though indirectly, mainly by means of changing the ground state geometry of the solvated complex when compared with the vacuum one. In particular, the ground state structure of the complex surrounded by effective fragments simulating water molecules provides the lowest CASSCF/MCQDPT excitation energy estimate to be within 25,500-26,400 cm-1, in a fair agreement with the experimentally measured value of 25,600 cm-1. At the same time, direct incorporation of solvation effects causes only minor change in the estimated transition energies, within several hundred cm-1.

  20. Titanium Dioxide/Upconversion Nanoparticles/Cadmium Sulfide Nanofibers Enable Enhanced Full-Spectrum Absorption for Superior Solar Light Driven Photocatalysis.

    PubMed

    Zhang, Fu; Zhang, Chuan-Ling; Wang, Wan-Ni; Cong, Huai-Ping; Qian, Hai-Sheng

    2016-06-22

    In this work, we demonstrate an electrospinning technique to fabricate TiO2 /upconversion nanoparticles (UCNPs)/CdS nanofibers on large scale. In addition, the as-prepared TiO2 nanofibers are incorporated with a high population of UCNPs and CdS nanospheres; this results in Förster resonance energy-transfer configurations of the UCNPs, TiO2 , and CdS nanospheres that are in close proximity. Hence, strong fluorescent emissions for the Tm(3+) ions including the (1) G4 →(3) H6 transition are efficiently transferred to TiO2 and the CdS nanoparticles through an energy-transfer process. The as-prepared TiO2 /UCNPs/CdS nanofibers exhibit full-spectrum solar-energy absorption and enable the efficient degradation of organic dyes by fluorescence resonance energy transfer between the UCNPs and TiO2 (or CdS). The UCNPs/TiO2 /CdS nanofibers may also have enhanced energy-transfer efficiency for wide applications in solar cells, bioimaging, photodynamics, and chemotherapy. PMID:27214754

  1. Pressure-dependence on the absorption spectrum of CuMoO 4: study of the green→brownish-red piezochromic phase transition at 2.5 kbar

    NASA Astrophysics Data System (ADS)

    Hernández, D.; Rodríguez, F.; Garcia-Jaca, J.; Ehrenberg, H.; Weitzel, H.

    1999-04-01

    The optical properties of CuMoO 4 are investigated by means of hydrostatic pressure techniques in the 0-60 kbar range. Attention is paid to the piezochromism exhibited by this crystal at the α (green)→γ (brownish red) structural phase transition. The variation of the absorption spectra with pressure indicates that the piezochromic transition takes place at 2.5 kbar. The associated change of colour is due to the broadening of the first O 2-→Cu 2+ charge transfer band and the disappearance of an intense band at 12000 cm -1, related to the presence of pyramidal CuO 5 complexes in α-CuMoO 4. The measured oscillator strength suggests that this band corresponds to the e→b 1 crystal field transition rather than to a charge transfer within CuO 5. The structural correlation with the absorption spectra performed in this work explains the strong dichroism exhibited by the crystal in the high-pressure γ-CuMoO 4.

  2. THE 3-5 {mu}m SPECTRUM OF NGC 1068 AT HIGH ANGULAR RESOLUTION: DISTRIBUTION OF EMISSION AND ABSORPTION FEATURES ACROSS THE NUCLEAR CONTINUUM SOURCE

    SciTech Connect

    Geballe, T. R.; Mason, R. E.; Rodriguez-Ardila, A.; Axon, D. J.

    2009-08-20

    We report moderate resolution 3-5 {mu}m spectroscopy of the nucleus of NGC 1068 obtained at 0.''3 (20 pc) resolution with the spectrograph slit aligned approximately along the ionization cones of the active galactic nucleus. The deconvolved full width at half-maximum of the nuclear continuum source in this direction is 0.''3. Four coronal lines of widely different excitations were detected; the intensity of each peaks near radio knot C, approximately 0.''3 north of the infrared continuum peak, where the radio jet changes direction. Together with the broadened line profiles observed near that location, this suggests that shock ionization is the dominant excitation mechanism of the coronal lines. The depth of the 3.4 {mu}m hydrocarbon absorption is maximum at and just south of the continuum peak, similar to the 10 {mu}m silicate absorption. That and the similar and rapid variations of the optical depths of both features across the nucleus suggest that substantial portions of both arise in a dusty environment just in front of the continuum source(s). A new and tighter limit is set on the column density of CO. Although clumpy models of the dust screen might explain the shallowness of the silicate feature, the presence of the 3.4 {mu}m feature and the absence of CO are strongly reminiscent of Galactic diffuse cloud environments and a consistent explanation for them and the observed silicate feature is found if all three phenomena occur in such an environment, existing as close as 10 pc to the central engine.

  3. The application of new methane line absorption data to Gemini-N/NIFS and KPNO/FTS observations of Uranus' near-infrared spectrum

    NASA Astrophysics Data System (ADS)

    Irwin, P. G. J.; de Bergh, C.; Courtin, R.; Bézard, B.; Teanby, N. A.; Davis, G. R.; Fletcher, L. N.; Orton, G. S.; Calcutt, S. B.; Tice, D.; Hurley, J.

    2012-08-01

    New line data describing the absorption of CH4 and CH3D from 1.26 to 1.71 μm (Campargue, A., Wang, L., Mondelain, D., Kassi, S., Bézard, B., Lellouch, E., Coustenis, A., de Bergh, C., Hirtzig, M., Drossart, P. [2012]. Icarus 219, 110-128), building upon previous papers by Campargue et al. (Campargue, A., Wang, L., Kassi, S., Masat, M., Votava, O. [2010]. J. Quant. Spectrosc. Radiat. Transfer 111, 1141-1151; Wang, L., Kassi, S., Campargue, A. [2010]. J. Quant. Spectrosc. Radiat. Transfer 111, 1130-1140; Wang, L., Kassi, S., Liu, A.W., Hu, S.M., Campargue, A. [2011]. J. Quant. Spectrosc. Radiat. Transfer 112, 937-951)) have been applied to the analysis of Gemini-N/NIFS observations of Uranus made in 2010 and compared with earlier disc-averaged observations made by KPNO/FTS in 1982. The new line data are found to improve greatly the fit to the observed spectra and present a huge advance over previous methane absorption tables by allowing us to determine the CH3D/CH4 ratio and also start to break the degeneracy between methane abundance and cloud top height. The best fits are obtained if the cloud particles in the main cloud deck at the 2-3 bar level become less scattering with wavelength across the 1.4-1.6 μm region and we have modelled this variation here by varying the extinction cross-section and single-scattering albedo of the particles. Applying the new line data to the NIFS spectra of Uranus, we determine a new estimate of the CH3D/CH4 ratio of 2.9-0.5+0.9×10-4, which is consistent with the estimate of de Bergh et al. (de Bergh, C., Lutz, B.L., Owen, T., Brault, J., Chauville, J. [1986]. Astrophys. J. 311, 501-510) of 3.6-2.8+3.6×10-4, made by fitting a disc-averaged KPNO/FTS spectrum measured in 1982, but much better constrained. The NIFS observations made in 2010 have been disc-averaged and compared with the 1982 KPNO/FTS spectrum and found to be in excellent agreement. Using k-tables fitted to the new line data, the central meridian observations of

  4. Influence of the size and protonation state of acidic residue 85 on the absorption spectrum and photoreaction of the bacteriorhodopsin chromophore

    NASA Technical Reports Server (NTRS)

    Lanyi, J. K.; Tittor, J.; Varo, G.; Krippahl, G.; Oesterhelt, D.

    1992-01-01

    The consequences of replacing Asp-85 with glutamate in bacteriorhodopsin, as expressed in Halobacterium sp. GRB, were investigated. Similarly to the in vitro mutated and in Escherichia coli expressed protein, the chromophore was found to exist as a mixture of blue (absorption maximum 615 nm) and red (532 nm) forms, depending on the pH. However, we found two widely separated pKa values (about 5.4 and 10.4 without added salt), arguing for two blue and two red forms in separate equilibria. Both blue and red forms of the protein are in the two-dimensional crystalline state. A single pKa, such as in the E. coli expressed protein, was observed only after solubilization with detergent. The photocycle of the blue forms was determined at pH 4.0 with 610 nm photoexcitation, and that of the red forms at pH 10.5 and with 520 nm photoexcitation, in the time-range of 100 ns to 1 s. The blue forms produced no M, but a K- and an L-like intermediate, whose spectra and kinetics resembled those of blue wild-type bacteriorhodopsin below pH 3. The red forms produced a K-like intermediate, as well as M and N. Only the red forms transported protons. Specific perturbation of the neighborhood of the Schiff base by the replacement of Asp-85 with glutamate was suggested by (1) the shift and splitting of the pKa for what is presumably the protonation of residue 85, (2) a 36 nm blue-shift in the absorption of the all-trans red chromophore and a 25 nm red-shift of the 13-cis N chromophore, as compared to wild-type bacteriorhodopsin and its N intermediate, and (3) significant acceleration of the deprotonation of the Schiff base at pH 7, but not of its reprotonation and the following steps in the photocycle.

  5. Enhanced squeezing by absorption

    NASA Astrophysics Data System (ADS)

    Grünwald, P.; Vogel, W.

    2016-04-01

    Absorption is usually expected to be detrimental to quantum coherence effects. However, there have been few studies into the situation for complex absorption spectra. We consider the resonance fluorescence of excitons in a semiconductor quantum well. The creation of excitons requires absorption of the incoming pump-laser light. Thus, the absorption spectrum of the medium acts as a spectral filter for the emitted light. Surprisingly, absorption can even improve quantum effects, as is demonstrated for the squeezing of the resonance fluorescence of the quantum-well system. This effect can be explained by an improved phase matching due to absorption.

  6. The absorption spectrum of water vapor in the 1.25 μm atmospheric window (7911-8337 cm-1)

    NASA Astrophysics Data System (ADS)

    Campargue, A.; Mikhailenko, S. N.; Lohan, Benoit Guillo; Karlovets, E. V.; Mondelain, D.; Kassi, S.

    2015-05-01

    The absorption spectrum of water vapor in "natural" isotopic abundance has been recorded at room temperature by high sensitivity Continuous Wave Cavity Ring Down Spectroscopy (CW-CRDS) between 7911 and 8337 cm-1. The investigated region covers most of the 1.25 μm transparency window of importance for atmospheric applications. The recordings were performed with sensitivity on the order of αmin~2×10-11 cm-1, more than two orders of magnitude better than previous investigations by Fourier Transform Spectroscopy (FTS). Measured line intensities cover a range of seven orders of magnitude (3×10-30-2×10-23 cm/molecule at room temperature). The experimental line list provided as Supplementary Material includes more than 5000 transitions. As a result of the achieved sensitivity, more than 1150 lines of the experimental list were identified as being due to ammonia present as an impurity at the 5 ppm concentration level in the water sample. Although incomplete, the obtained ammonia line list seems to be the first one in the region. More than 3193 water lines were assigned to 3560 transitions of five water isotopologues (H216O, H218O, H217O, HD16O and HD18O). The assignments were performed using known experimental energy levels and calculated spectra based on variational calculations by Schwenke and Partridge. The obtained results are compared to the most relevant previous studies by Fourier Transform Spectroscopy in the region and to the exhaustive review of rovibrational line positions and levels performed recently by an IUPAC sponsored task group. Two-hundred and sixty-six levels are newly determined and 46 are corrected by more than 0.015 cm-1 compared to those recommended by the water IUPAC task group. The overall agreement between variational and measured intensities is satisfactory. A complete empirical list of 4473 transitions incorporating all the experimental information at disposal was constructed for water in the studied region. The intensity cut-off was fixed

  7. Ultraviolet to near-infrared absorption spectrum of carbon dioxide ice from 0.174 to 1.8 μm

    NASA Astrophysics Data System (ADS)

    Hansen, Gary B.

    2005-11-01

    A laboratory experiment was devised to measure transmission at fine spectral resolution through thick, high-quality samples of CO2 ice over an extended wavelength range. The absorption coefficient throughout the ultraviolet and near-infrared spectral ranges 0.174-1.8 μm (5555-57,470 cm-1 in wave number) is presented here. CO2 ice samples were grown at a temperature of 150 K, typical of the Martian polar caps. The path length of the samples varied from 1.6 to 107.5 mm, allowing the measurement of absorption from <0.1 to 4000 m-1. The experiment used both a grating monochromator (with spectral resolution 0.1-0.3 nm) and a Fourier transform spectrometer (with an effective resolution of <1.0 cm-1). The transmission data for five thicknesses are used to estimate both the scattering losses for each sample and the absorption coefficient at each wavelength. The uncertainty in the most transparent wavelength regions (<10 m-1) is due to scattering extinction. Measurement noise and data scatter produce significant uncertainty only where absorption coefficients exceed 1000 m-1. Between 1.0 and 1.8 μm there are several weak to moderate absorption lines. Only an upper limit to the absorption can be determined in many places; e.g., the absorption from ~0.25 to 1.0 μm is below the detection limit. The estimated visible absorption, ~10-2 m-1, is a factor of 1000 smaller than the values reported by Egan and Spagnolo, which have been used previously to compute albedos of CO2 snow. The new results should be useful for studies of the seasonal polar caps of Mars.

  8. Enhanced Hydrogen Evolution in the Presence of Plasmonic Au-Photo-Sensitized g-C3N4 with an Extended Absorption Spectrum from 460 to 640 nm.

    PubMed

    Xie, Lihong; Ai, Zhuyu; Zhang, Meng; Sun, Runze; Zhao, Weirong

    2016-01-01

    Extensively spectral-responsive photocatalytic hydrogen production was achieved over g-C3N4 photo-sensitized by Au nanoparticles. The photo-sensitization, which was achieved by a facile photo-assisted reduction route, resulted in an extended spectral range of absorption from 460 to 640 nm. The photo-sensitized g-C3N4 (Au/g-C3N4) photocatalysts exhibit significantly enhanced photocatalytic hydrogen evolution with a TOF value of 223 μmol g-1 h-1, which is a 130-fold improvement over g-C3N4. The hydrogen production result confirms that Au nanoparticles are effective photo-sensitizers for the visible light-responsive substrate g-C3N4. UV-vis diffuse reflection spectra (DRS), photoluminescence spectra (PL), electron spin resonance (ESR), and electrochemical measurements were used to investigate the transfer process of photogenerated electrons. The optimal Au/g-C3N4 photocatalyst displays the lowest charge transfer resistance of 18.45 Ω cm-2 and a high electron transfer efficiency, as determined by electrochemical impedance spectroscopy (EIS). The photo-sensitized g-C3N4 shows a broad range of response to visible light (400-640 nm), with significantly high incident photon-to-current efficiency (IPCE) values of 14.52%, 2.9%, and 0.74% under monochromatic light irradiation of 400, 550, and 640 nm, respectively. ESR characterization suggests that Au nanoparticles are able to absorb visible light of wavelengths higher than 460 nm and to generate hot electrons due to the SPR effect. PMID:27575246

  9. Enhanced Hydrogen Evolution in the Presence of Plasmonic Au-Photo-Sensitized g-C3N4 with an Extended Absorption Spectrum from 460 to 640 nm

    PubMed Central

    Xie, Lihong; Ai, Zhuyu; Zhang, Meng; Sun, Runze; Zhao, Weirong

    2016-01-01

    Extensively spectral-responsive photocatalytic hydrogen production was achieved over g-C3N4 photo-sensitized by Au nanoparticles. The photo-sensitization, which was achieved by a facile photo-assisted reduction route, resulted in an extended spectral range of absorption from 460 to 640 nm. The photo-sensitized g-C3N4 (Au/g-C3N4) photocatalysts exhibit significantly enhanced photocatalytic hydrogen evolution with a TOF value of 223 μmol g-1 h-1, which is a 130-fold improvement over g-C3N4. The hydrogen production result confirms that Au nanoparticles are effective photo-sensitizers for the visible light-responsive substrate g-C3N4. UV–vis diffuse reflection spectra (DRS), photoluminescence spectra (PL), electron spin resonance (ESR), and electrochemical measurements were used to investigate the transfer process of photogenerated electrons. The optimal Au/g-C3N4 photocatalyst displays the lowest charge transfer resistance of 18.45 Ω cm-2 and a high electron transfer efficiency, as determined by electrochemical impedance spectroscopy (EIS). The photo-sensitized g-C3N4 shows a broad range of response to visible light (400–640 nm), with significantly high incident photon-to-current efficiency (IPCE) values of 14.52%, 2.9%, and 0.74% under monochromatic light irradiation of 400, 550, and 640 nm, respectively. ESR characterization suggests that Au nanoparticles are able to absorb visible light of wavelengths higher than 460 nm and to generate hot electrons due to the SPR effect. PMID:27575246

  10. XMM-Newton/Reflection Grating Spectrometer detection of the missing interstellar O VII Kα absorption line in the spectrum of Cyg X-2

    NASA Astrophysics Data System (ADS)

    Cabot, Samuel H. C.; Wang, Q. Daniel; Yao, Yangsen

    2013-05-01

    The hot interstellar medium is an important part of the Galactic ecosystem and can be effectively characterized through X-ray absorption line spectroscopy. However, in a study of the hot medium using the accreting neutron star X-ray binary, Cyg X-2, as a background light source, a mystery came about when the putatively strong O VII Kα line was not detected in Chandra grating observations, while other normally weaker lines such as O VII Kβ as well as O VI and O VIII Kα are clearly present. We have investigated the grating spectra of Cyg X-2 from 10 XMM-Newton observations, in search of the missing line. We detect it consistently in nine of these observations, but the line is absent in the remaining one observation or is inconsistent with the detection in others at a ˜4σ confidence level. This absence of the line resembles that seen in the Chandra observations. Similarly, the O VI Kα line is found to disappear occasionally, but not in concert with the variation of the O VII Kα line. All these variations are most likely due to the presence of changing O VII and O VI Kα emission lines of Cyg X-2, which are blurred together with the absorption ones in the X-ray spectra. A re-examination of the Chandra grating data indeed shows evidence for a narrow emission line slightly off the O VI Kα absorption line. We further show that narrow N V emission lines with varying centroids and fluxes are present in far-ultraviolet spectra from the Cosmic Origins Spectrograph aboard the Hubble Space Telescope. These results provide new constraints on the accretion around the neutron star and on the X-ray-heating of the stellar companion. The understanding of these physical processes is also important to the fidelity of using such local X-ray binaries for interstellar absorption line spectroscopy.

  11. LED-Based Fourier Transform Spectroscopy: the HD16O Absorption Spectrum in the Range of 11200-12400 cm-1

    NASA Astrophysics Data System (ADS)

    Sinitsa, L. N.; Serdyukov, V. I.; Polovtseva, E. R.; Shcherbakov, A. P.; Voronin, B. A.; Bykov, A. D.

    2016-03-01

    The vibrational—rotational spectrum of the HD16O molecule is studied within the range of 11200-12400 cm-1. The spectrum is recorded by an IFS-125M Fourier spectrometer with a resolution of 0.05 cm-1. The measurements are performed using a multipass White cell. A light-emitting diode is used as a radiation source. The signal-to-noise ratio was about 104. The centers, intensities, and half-widths of the spectral lines are determined by fitting to the experimental data by the least-squares method. A linelist containing more than 1500 lines is created. The results obtained are compared with the experimental data of other authors.

  12. The Complete Ultraviolet Spectrum of the Archetypal "Wind-dominated" Quasar Mrk 231: Absorption and Emission from a High-speed Dusty Nuclear Outflow

    NASA Astrophysics Data System (ADS)

    Veilleux, S.; Meléndez, M.; Tripp, T. M.; Hamann, F.; Rupke, D. S. N.

    2016-07-01

    New near- and far-ultraviolet (NUV and FUV) Hubble Space Telescope spectra of Mrk 231, the nearest quasar known, are combined with ground-based optical spectra to study the remarkable dichotomy between the FUV and NUV–optical spectral regions in this object. The FUV emission-line features are faint, broad, and highly blueshifted (up to ˜7000 km s‑1), with no significant accompanying absorption. In contrast, the profiles of the NUV absorption features resemble those of the optical Na i D, He i, and Ca ii H and K lines, exhibiting broad blueshifted troughs that overlap in velocity space with the FUV emission-line features and indicate a dusty, high-density and patchy broad absorption line (BAL) screen covering ˜90% of the observed continuum source at a distance ≲2–20 pc. The FUV continuum emission does not show the presence of any obvious stellar features and is remarkably flat compared with the steeply declining NUV continuum. The NUV (FUV) features and continuum emission have not varied significantly over the past ˜22 (3) years and are unresolved on scales ˜40 (170) pc. These results favor an active galactic nucleus origin for the NUV–FUV line and continuum emission. The observed FUV line emission is produced in the outflowing BAL cloud system, while the Balmer lines arise primarily from the standard broad line region seen through the dusty BAL screen. Our data are inconsistent with the recently proposed binary black hole model. We argue instead that Mrk 231 is the nearest example of weak-lined “wind-dominated” quasars with high Eddington ratios and geometrically thick (“slim”) accretion disks; these quasars are likely more common in the early universe.

  13. Experimental and theoretical study of absorption spectrum of the (CH3)2CO···HF complex. Influence of anharmonic interactions on the frequency and intensity of the C=O and H-F stretching bands.

    PubMed

    Bulychev, V P; Svishcheva, E A; Tokhadze, K G

    2014-01-01

    IR absorption spectra of mixtures (CH3)2CO/HF and free (CH3)2CO molecules are recorded in the region of 4000-900 cm(-1) with a Bruker IFS-125 HR vacuum Fourier spectrometer at room temperature with a resolution up to 0.02 cm(-1). Spectral characteristics of the 2ν(C=O) overtone band of free acetone are reliably measured. The ν1(HF) and ν(C=O) absorption bands of the (CH3)2CO···HF complex are obtained by subtracting the absorption bands of free HF and acetone and absorption lines of atmospheric water from the experimental spectrum of mixtures. The experimental data are compared with theoretical results obtained from variational solutions of 1D-4D vibrational Schrödinger equations. The anharmonic potential energy and dipole moment surfaces used in the calculations were computed in the MP2/6-311++G(2d,2p) approximation with corrections for the basis set superposition error. Comparison of the data derived from solutions for different combinations of vibrational degrees of freedom shows that taking the inter-mode anharmonic interactions into account has different effects on the transition frequencies and intensities. Particular attention has been given to elucidation of the influence of anharmonic coupling of the H-F and C=O stretches with the low-frequency intermolecular modes on their frequencies and intensities and the strength of resonance between the fundamental H-F and the first overtone C=O transitions. PMID:24128921

  14. The X-ray absorption spectrum of 4U1700-37 and its implications for the stellar wind of the companion HD153919

    NASA Technical Reports Server (NTRS)

    White, N. E.; Kallman, T. R.; Swank, J. H.

    1982-01-01

    The first high resolution non-dispersive 2-60 KeV X-ray spectra of 4U1700-37 is presented. The continuum is typical of that found from X-ray pulsars; that is a flat power law between 2 and 10 keV and, beyond 10 keV, an exponential decay of characteristic energy varying between 10 and 20 keV. No X-ray pulsations were detected between 160 ms and 6 min with an amplitude greater than approximately 2%. The absorption measured at binary phases approximately 0.72 is comparable to that expected from the stellar wind of the primary. The gravitational capture of material in the wind is found to be more than enough to power the X-ray source. The increase in the average absorption after phi o approximately 0.5 is confirmed. The minimum level of adsorption is a factor of 2 or 3 lower than that reported by previous observers, which may be related to a factor of approximately 10 decline in the average X-ray luminosity over the same interval. Short term approximately 50% variations in adsorption are seen for the first time which appear to be loosely correlated with approximately 10 min flickering activity in the X-ray flux. These most likely originate from inhomogeneities in the stellar wind of the primary.

  15. Communication: THz absorption spectrum of the CO{sub 2}–H{sub 2}O complex: Observation and assignment of intermolecular van der Waals vibrations

    SciTech Connect

    Andersen, J.; Mahler, D. W.; Larsen, R. Wugt; Heimdal, J.; Nelander, B.

    2014-03-07

    Terahertz absorption spectra have been recorded for the weakly bound CO{sub 2}–H{sub 2}O complex embedded in cryogenic neon matrices at 2.8 K. The three high-frequency van der Waals vibrational transitions associated with out-of-plane wagging, in-plane rocking, and torsional motion of the isotopic H{sub 2}O subunit have been assigned and provide crucial observables for benchmark theoretical descriptions of this systems’ flat intermolecular potential energy surface. A (semi)-empirical value for the zero-point energy of 273 ± 15 cm{sup −1} from the class of intermolecular van der Waals vibrations is proposed and the combination with high-level quantum chemical calculations provides a value of 726 ± 15 cm{sup −1} for the dissociation energy D{sub 0}.

  16. Novel Technique for Improving the Signal-to-Background Ratio of X-ray Absorption Near-Edge Structure Spectrum in Fluorescence Mode and Its Application to the Chemical State Analysis of Magnesium Doped in GaN

    NASA Astrophysics Data System (ADS)

    Yonemura, Takumi; Iihara, Junji; Saito, Yoshihiro; Ueno, Masaki

    2013-12-01

    A novel measurement technique for an X-ray absorption near-edge structure (XANES) for magnesium (Mg) doped in gallium nitride (GaN) has been developed. XANES spectra from Mg at very low concentrations of 1 ×1018/cm3 doped in GaN have successfully been obtained by optimizing the region of interest (ROI) and by using highly brilliant synchrotron radiation X-rays of SPring-8. The ROI is the limited energy region from an X-ray fluorescence spectrum to elicit signals of particular atoms. Using this new technique, we have investigated the effect of the annealing process for Mg-doped GaN on the XANES spectra. It has been found that the XANES spectra of Mg significantly changed as the annealing temperature increased. This indicates that the local structure around Mg atoms in GaN was modified by the annealing process.

  17. Structural and optical study of core–shell InGaN layers of nanorod arrays with multiple stacks of InGaN/GaN superlattices for absorption of longer solar spectrum

    NASA Astrophysics Data System (ADS)

    Bae, Si-Young; Jung, Byung Oh; Lekhal, Kaddour; Lee, Dong-Seon; Deki, Manato; Honda, Yoshio; Amano, Hiroshi

    2016-05-01

    We report on the material and optical properties of core–shell InGaN layers grown on GaN nanorod arrays. The core–shell InGaN layers were well grown on polarization-reduced surfaces such as semipolar pyramids and nonpolar sidewalls. In addition, to compensate the biaxial strain between GaN and InGaN layers, we grew interlayers underneath a thick InGaN layer. Here, the interlayers were composed of multiple superlattice structures. We could observe that the indium composition of core–shell InGaN structures increased with the number of interlayers. This indicates that the absorption energy band of InGaN alloys can be better matched to the spectral irradiance of the solar spectrum in nature. We also implemented a simulation of Ga-polar and nonpolar InGaN-based solar cells based on the indium composition obtained from the experiments. The result showed that nonpolar InGaN solar cells had a much higher efficiency than Ga-polar InGaN solar cells with the same thickness of the absorption layer.

  18. Two-photon solvatochromism II: experimental and theoretical study of solvent effects on the two-photon absorption spectrum of Reichardt's dye.

    PubMed

    Wielgus, Małgorzata; Zaleśny, Robert; Murugan, N Arul; Kongsted, Jacob; Ågren, Hans; Samoc, Marek; Bartkowiak, Wojciech

    2013-11-11

    In this study, we report on the influence of solvent on the two-photon absorption (2PA) spectra of Reichardt's dye (RD). The measurement of 2PA cross-sections is performed for three solvents (chloroform, dimethyl formamide, and dimethyl sulfoxide) using the Z-scan technique. The key finding of this study is the observation that the cross-section, corresponding to the 2PA of the intramolecular charge-transfer state, diminishes substantially upon increasing the solvent polarity. To unravel the solvent dependence of the 2PA cross-section, the electronic structure of RD is determined using a hybrid quantum mechanics/molecular mechanics (QM/MM) approach, in which polarization between the solute and solvent is taken into account by using a self-consistent scheme in the solvent polarization. The two-state approximation proves to be adequate for the studied system, and allowed the observed solvent-polarity-induced decrease of the 2PA cross-section to be related to the decrease of the transition moment and the increase in the excitation energy. PMID:24106066

  19. [PHOSPHOLIPIDS AND FATTY ACIDS IN ERYTHROCYTES OF THE LAMPREY LAMPETRA FLUVIATILIS DURING AUTUMN PRESPAWNING PERIOD AND THE ABSORPTION SPECTRUM OF THEIR LIPID EXTRACT].

    PubMed

    Zabelinskii, S A; Chebotareva, M A; Shukolyukova, E P; Krivchenko, A I

    2015-01-01

    The content of some classes of phospholipids and their fatty acid composition in erythrocytes of the lamprey Lampetrafluviatilis during the autumn period of its prespawning migration are investigated. It is found that the phospholipid spectrum of erythrocytes of the lamprey, the oldest representative of vertebrates, is similar to that of many mammals. A four-fold prevalence of phosphatidilcholine content over sphingomyelin content as well as prevalence of (ω3-acids over ω6-acids indicates the of lamprey's erythrocyte membranes - an important indicator of deformational ability of lamprey's erythrocytes. Phosphatidilethanol amine and its plasmalogenic form are the most unsaturated phospholipids (their unsaturation indices are 230 and 342, correspondingly). Phosphatidilcholine is the most saturated one (UI is 167). It is found that the basic acid indicators characterizing the fluidity of erythrocyte membranes remain unchanged during the whole period of prespawning migration of lampreys up to spawning. The blood contains several buffer systems, in particular, membrane phospholipids which neutralize acids and alkali incoming into the blood. In the process of organism life a change of pH inside erythrocytes occurs. One can suppose that the base of the system associated with buffer properties of the blood is water dissociation. Inside thin vessels of the circulatory system the hemoglobin attaches and returns molecules of oxygen due to interaction of the buffer systems with water. The property of water to dissociate as well as ion transfer produce in erythrocytes, lying within narrow vessels of the circulatory system, a local pH alteration allowing displacing/attaching the molecule of oxygen from hemoglobin. PMID:26547949

  20. Hypnosis, suggestion, and suggestibility: an integrative model.

    PubMed

    Lynn, Steven Jay; Laurence, Jean-Roch; Kirsch, Irving

    2015-01-01

    This article elucidates an integrative model of hypnosis that integrates social, cultural, cognitive, and neurophysiological variables at play both in and out of hypnosis and considers their dynamic interaction as determinants of the multifaceted experience of hypnosis. The roles of these variables are examined in the induction and suggestion stages of hypnosis, including how they are related to the experience of involuntariness, one of the hallmarks of hypnosis. It is suggested that studies of the modification of hypnotic suggestibility; cognitive flexibility; response sets and expectancies; the default-mode network; and the search for the neurophysiological correlates of hypnosis, more broadly, in conjunction with research on social psychological variables, hold much promise to further understanding of hypnosis. PMID:25928681

  1. Multiplasmon Absorption in Graphene

    NASA Astrophysics Data System (ADS)

    Jablan, Marinko; Chang, Darrick E.

    2015-06-01

    We show that graphene possesses a strong nonlinear optical response in the form of multiplasmon absorption, with exciting implications in classical and quantum nonlinear optics. Specifically, we predict that graphene nanoribbons can be used as saturable absorbers with low saturation intensity in the far-infrared and terahertz spectrum. Moreover, we predict that two-plasmon absorption and extreme localization of plasmon fields in graphene nanodisks can lead to a plasmon blockade effect, in which a single quantized plasmon strongly suppresses the possibility of exciting a second plasmon.

  2. Chaotic Systems with Absorption

    NASA Astrophysics Data System (ADS)

    Altmann, Eduardo G.; Portela, Jefferson S. E.; Tél, Tamás

    2013-10-01

    Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe absorption in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape rate κ in terms of the natural conditionally invariant measure of the system, (ii) an increased multifractality when compared to the spectrum of dimensions Dq obtained without taking absorption and return times into account, and (iii) a generalization of the Kantz-Grassberger formula that expresses D1 in terms of κ, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection rate. Simulations in the cardioid billiard confirm these results.

  3. Open to Suggestion.

    ERIC Educational Resources Information Center

    Journal of Reading, 1987

    1987-01-01

    Offers (1) suggestions for improving college students' study skills; (2) a system for keeping track of parent, teacher, and community contacts; (3) suggestions for motivating students using tic tac toe; (4) suggestions for using etymology to improve word retention; (5) a word search grid; and (6) suggestions for using postcards in remedial reading…

  4. K- and L-edge X-ray absorption spectrum calculations of closed-shell carbon, silicon, germanium, and sulfur compounds using damped four-component density functional response theory.

    PubMed

    Fransson, Thomas; Burdakova, Daria; Norman, Patrick

    2016-05-21

    X-ray absorption spectra of carbon, silicon, germanium, and sulfur compounds have been investigated by means of damped four-component density functional response theory. It is demonstrated that a reliable description of relativistic effects is obtained at both K- and L-edges. Notably, an excellent agreement with experimental results is obtained for L2,3-spectra-with spin-orbit effects well accounted for-also in cases when the experimental intensity ratio deviates from the statistical one of 2 : 1. The theoretical results are consistent with calculations using standard response theory as well as recently reported real-time propagation methods in time-dependent density functional theory, and the virtues of different approaches are discussed. As compared to silane and silicon tetrachloride, an anomalous error in the absolute energy is reported for the L2,3-spectrum of silicon tetrafluoride, amounting to an additional spectral shift of ∼1 eV. This anomaly is also observed for other exchange-correlation functionals, but it is seen neither at other silicon edges nor at the carbon K-edge of fluorine derivatives of ethene. Considering the series of molecules SiH4-XFX with X = 1, 2, 3, 4, a gradual divergence from interpolated experimental ionization potentials is observed at the level of Kohn-Sham density functional theory (DFT), and to a smaller extent with the use of Hartree-Fock. This anomalous error is thus attributed partly to difficulties in correctly emulating the electronic structure effects imposed by the very electronegative fluorines, and partly due to inconsistencies in the spurious electron self-repulsion in DFT. Substitution with one, or possibly two, fluorine atoms is estimated to yield small enough errors to allow for reliable interpretations and predictions of L2,3-spectra of more complex and extended silicon-based systems. PMID:27136720

  5. The Life of Suggestions

    ERIC Educational Resources Information Center

    Pearce, Cathie

    2010-01-01

    Using the notion of a suggestion, or rather charting the life of suggestions, this article considers the happenings of chance and embodiment as the "problems that got away." The life of suggestions helps us to ask how connectivities are made, how desire functions, and how "immanence" rather than "transcendence" can open up the politics and ethics…

  6. Suggestion and psychoanalytic technique.

    PubMed

    Levy, S T; Inderbitzin, L B

    2000-01-01

    The role of the analyst's suggestive influence on the course and outcome of psychoanalytic treatment is explored, and traditional and newer perspectives on analytic technique are contrasted. The intersubjective critique of the neutral, objective analyst in relation to suggestion is examined. The inevitable presence and need for suggestive factors in analysis, and the relationship of suggestion to transference susceptibility, are emphasized. The manner in which the analysis of suggestive factors is subsumed in transference analysis as part of traditional technique is highlighted. PMID:11059395

  7. Zellweger Spectrum

    MedlinePlus

    ... the Zellweger spectrum result from defects in the assembly of a cellular structure called the peroxisome, and ... Zellweger spectrum are caused by defects in the assembly of the peroxisome. There are at least 12 ...

  8. Cholesterol absorption.

    PubMed

    Ostlund, Richard E

    2002-03-01

    Cholesterol absorption is a key regulatory point in human lipid metabolism because it determines the amount of endogenous biliary as well as dietary cholesterol that is retained, thereby influencing whole body cholesterol balance. Plant sterols (phytosterols) and the drug ezetimibe reduce cholesterol absorption and low-density lipoprotein cholesterol in clinical trials, complementing the statin drugs, which inhibit cholesterol biosynthesis. The mechanism of cholesterol absorption is not completely known but involves the genes ABC1, ABCG5, and ABCG8, which are members of the ATP-binding cassette protein family and appear to remove unwanted cholesterol and phytosterols from the enterocyte. ABC1 is upregulated by the liver X (LXR) and retinoid X (RXR) nuclear receptors. Acylcholesterol acytransferase-2 is an intestinal enzyme that esterifies absorbed cholesterol and increases cholesterol absorption when dietary intake is high. New clinical treatments based on better understanding of absorption physiology are likely to substantially improve clinical cholesterol management in the future. PMID:17033296

  9. Dipeptide absorption in man

    PubMed Central

    Hellier, M. D.; Holdsworth, C. D.; McColl, I.; Perrett, D.

    1972-01-01

    A quantitative perfusion method has been used to study intestinal absorption of two dipeptides—glycyl-glycine and glycyl-l-alanine—in normal subjects. In each case, the constituent amino acids were absorbed faster when presented as dipeptides than as free amino acids, suggesting intact dipeptide transport. During absorption constituent amino acids were measured within the lumen and it is suggested that these represent amino acids which have diffused back to the lumen after absorption as dipeptide. Portal blood analyses during absorption of a third dipeptide, glycyl-l-lysine, have shown that this dipeptide, known to be transported intact from the intestinal lumen, is hydrolysed to its constitutent amino acids before it reaches portal venous blood. PMID:4652039

  10. [Therapy and suggestion].

    PubMed

    Barrucand, D; Paille, F

    1986-12-01

    Therapy and suggestion are closely related. That is clear for the ancient time: primitive medicine gives a good place to the Word. In plant, animal or mineral remedies, the suggestion is clearly preponderant. Towards the end of the 19th century, the "Ecole de Nancy" sets up a real theory of the suggestion, and Bernheim, its leader, bases hypnosis, then psychotherapy on this concept. Thereafter Coué will bring up the "conscious autosuggestion". Today, despite the progress of scientific medicine, the part of suggestion is still very important in medical therapy (with or without drugs), or in chirurgical therapy; this part is also very important in psychotherapies, whatever has been said in this field. This has to be known and used consciously in the doctor-patient relation, which is always essential in the therapeutic effectiveness. PMID:3555209

  11. Direct MD Simulations of Terahertz Absorption and 2D Spectroscopy Applied to Explosive Crystals.

    PubMed

    Katz, G; Zybin, S; Goddard, W A; Zeiri, Y; Kosloff, R

    2014-03-01

    A direct molecular dynamics simulation of the THz spectrum of a molecular crystal is presented. A time-dependent electric field is added to a molecular dynamics simulation of a crystal slab. The absorption spectrum is composed from the energy dissipated calculated from a series of applied pulses characterized by a carrier frequency. The spectrum of crystalline cyclotrimethylenetrinitramine (RDX) and triacetone triperoxide (TATP) were simulated with the ReaxFF force field. The proposed direct method avoids the linear response and harmonic approximations. A multidimensional extension of the spectroscopy is suggested and simulated based on the nonlinear response to a single polarized pulse of radiation in the perpendicular polarization direction. PMID:26274066

  12. DISCOVERY OF THE TRANSITION OF A MINI-BROAD ABSORPTION LINE INTO A BROAD ABSORPTION LINE IN THE SDSS QUASAR J115122.14+020426.3

    SciTech Connect

    Hidalgo, Paola Rodriguez; Eracleous, Michael; Charlton, Jane; Hamann, Fred; Murphy, Michael T.; Nestor, Daniel

    2013-09-20

    We present the detection of a rare case of dramatic strengthening in the UV absorption profiles in the spectrum of the quasar J115122.14+020426.3 between observations {approx}2.86 yr apart in the quasar rest frame. A spectrum obtained in 2001 by the Sloan Digital Sky Survey shows a C IV ''mini-broad'' absorption line (FWHM = 1220 km s{sup -1}) with a maximum blueshift velocity of {approx}9520 km s{sup -1}, while a later spectrum from the Very Large Telescope shows a significantly broader and stronger absorption line, with a maximum blueshift velocity of {approx}12, 240 km s{sup -1} that qualifies as a broad absorption line. A similar variability pattern is observed in two additional systems at lower blueshifted velocities and in the Ly{alpha} and N V transitions as well. One of the absorption systems appears to be resolved and shows evidence for partial covering of the quasar continuum source (C{sub f} {approx} 0.65), indicating a transverse absorber size of, at least, {approx}6 Multiplication-Sign 10{sup 16} cm. In contrast, a cluster of narrower C IV lines appears to originate in gas that fully covers the continuum and broad emission line sources. There is no evidence for changes in the centroid velocity of the absorption troughs. This case suggests that at least some of the absorbers that produce ''mini-broad'' and broad absorption lines in quasar spectra do not belong to intrinsically separate classes. Here, the ''mini-broad'' absorption line is most likely interpreted as an intermediate phase before the appearance of a broad absorption line due to their similar velocities. While the current observations do not provide enough constraints to discern among the possible causes for this variability, future monitoring of multiple transitions at high resolution will help achieve this goal.

  13. Quasar Absorption Studies

    NASA Technical Reports Server (NTRS)

    Mushotzky, Richard (Technical Monitor); Elvis, Martin

    2004-01-01

    The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

  14. Optical absorption of silicon nanowires

    SciTech Connect

    Xu, T.; Lambert, Y.; Krzeminski, C.; Grandidier, B.; Stievenard, D.; Leveque, G.; Akjouj, A.; Pennec, Y.; Djafari-Rouhani, B.

    2012-08-01

    We report on simulations and measurements of the optical absorption of silicon nanowires (NWs) versus their diameter. We first address the simulation of the optical absorption based on two different theoretical methods: the first one, based on the Green function formalism, is useful to calculate the scattering and absorption properties of a single or a finite set of NWs. The second one, based on the finite difference time domain (FDTD) method, is well-adapted to deal with a periodic set of NWs. In both cases, an increase of the onset energy for the absorption is found with increasing diameter. Such effect is experimentally illustrated, when photoconductivity measurements are performed on single tapered Si nanowires connected between a set of several electrodes. An increase of the nanowire diameter reveals a spectral shift of the photocurrent intensity peak towards lower photon energies that allow to tune the absorption onset from the ultraviolet radiations to the visible light spectrum.

  15. Spectrum Recombination.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1984-01-01

    Describes several methods of executing lecture demonstrations involving the recombination of the spectrum. Groups the techniques into two general classes: bringing selected portions of the spectrum together using lenses or mirrors and blurring the colors by rapid movement or foreshortening. (JM)

  16. Chaotic systems with absorption.

    PubMed

    Altmann, Eduardo G; Portela, Jefferson S E; Tél, Tamás

    2013-10-01

    Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe absorption in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape rate κ in terms of the natural conditionally invariant measure of the system, (ii) an increased multifractality when compared to the spectrum of dimensions D(q) obtained without taking absorption and return times into account, and (iii) a generalization of the Kantz-Grassberger formula that expresses D(1) in terms of κ, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection rate. Simulations in the cardioid billiard confirm these results. PMID:24138240

  17. Learning Semantic Query Suggestions

    NASA Astrophysics Data System (ADS)

    Meij, Edgar; Bron, Marc; Hollink, Laura; Huurnink, Bouke; de Rijke, Maarten

    An important application of semantic web technology is recognizing human-defined concepts in text. Query transformation is a strategy often used in search engines to derive queries that are able to return more useful search results than the original query and most popular search engines provide facilities that let users complete, specify, or reformulate their queries. We study the problem of semantic query suggestion, a special type of query transformation based on identifying semantic concepts contained in user queries. We use a feature-based approach in conjunction with supervised machine learning, augmenting term-based features with search history-based and concept-specific features. We apply our method to the task of linking queries from real-world query logs (the transaction logs of the Netherlands Institute for Sound and Vision) to the DBpedia knowledge base. We evaluate the utility of different machine learning algorithms, features, and feature types in identifying semantic concepts using a manually developed test bed and show significant improvements over an already high baseline. The resources developed for this paper, i.e., queries, human assessments, and extracted features, are available for download.

  18. Absorption-line measurements of AGN outflows

    NASA Astrophysics Data System (ADS)

    Fields, Dale L.

    Investigations into the elemental abundances in two nearby active galaxies, the narrow-line Seyfert 1 Markarian 1044 and the Seyfert 1 Markarian 279, are reported. Spectra from three space-based observatories HST, FUSE, and CHANDRA, are used to measure absorption lines in material outflowing from the nucleus. I make multi-wavelength comparisons to better convert the ionic column densities into elemental column densities which can then be used to determine abundances (metallicities). Narrow-line Seyfert 1 galaxies are known to have extreme values of a number of properties compared to active galactic nuclei (AGNs) as a class. In particular, emission-line studies have suggested that NLS1s are unusually metal-rich compared to broad-line AGNs of comparable luminosity. To test these suggestions I perform absorption-line studies on the NLS1 Markarian 1044, a nearby and bright AGN. I use lines of H I, C IV, N V, and O VI to properly make the photoionization correction through the software Cloudy and determine abundances of Carbon, Nitrogen and Oxygen. I find two results. The first is that Markarian 1044 has a bulk metallicity greater than five times solar. The second is that the N/C ratio in Markarian 1044 is consistent with a solar mixture. This is in direct contradiction of extrapolations from local H II regions which state N/ C should scale with bulk metallicity. This implies a different enrichment history in Markarian 1044 than in the Galactic disk. I also report discovery of three new low-redshift Lya forest lines with log N HI >= 12:77 in the spectrum of Markarian 1044. This number is consistent with the 2.6 expected Lya forest lines in the path length to Markarian 1044. I also investigate the CHANDRA X-ray spectrum of Markarian 279, a broad-line Seyfert 1. I use a new code, PHASE, to self-consistently model the entire absorption spectrum simultaneously. Using solely the X-ray spectrum I am able to determine the physical parameters of this absorber to a degree only

  19. Ultraviolet absorption and luminescence of matrix-isolated adenine

    SciTech Connect

    Polewski, K.; Sutherland, J.; Zinger, D.; Trunk, J.

    2011-10-01

    We have investigated the absorption, the fluorescence and phosphorescence emission and the fluorescence lifetimes of adenine in low-temperature argon and nitrogen matrices at 15 K. Compared to other environments the absorption spectrum shows higher intensity at the shortest wavelengths, and a weak apparent absorption peak is observed at 280 nm. The resolved fluorescence excitation spectrum has five peaks at positions corresponding to those observed in the absorption spectrum. The position of the fluorescence maximum depends on the excitation wavelength. Excitation below 220 nm displays a fluorescence maximum at 305 nm, while for excitations at higher wavelengths the maximum occurs at 335 nm. The results suggest that multiple-emission excited electronic states are populated in low-temperature gas matrices. Excitation at 265 nm produces a phosphorescence spectrum with a well-resolved vibrational structure and a maximum at 415 nm. The fluorescence decays corresponding to excitation at increasing energy of each resolved band could be fit with a double exponential, with the shorter and longer lifetimes ranging from 1.7 to 3.3 ns and from 12 to 23 ns, respectively. Only for the excitation at 180 nm one exponential is required, with the calculated lifetimes of 3.3 ns. The presented results provide an experimental evidence of the existence of multiple site-selected excited electronic states, and may help elucidate the possible deexcitation pathways of adenine. The additional application of synchrotron radiation proved to result in a significant enhancement of the resolution and spectral range of the phenomena under investigation.

  20. Absorption Features in Soil Spectra Assessment.

    PubMed

    Vašát, Radim; Kodešová, Radka; Borůvka, Luboš; Jakšík, Ondřej; Klement, Aleš; Drábek, Ondřej

    2015-12-01

    From a wide range of techniques appropriate to relate spectra measurements with soil properties, partial least squares (PLS) regression and support vector machines (SVM) are most commonly used. This is due to their predictive power and the availability of software tools. Both represent exclusively statistically based approaches and, as such, benefit from multiple responses of soil material in the spectrum. However, physical-based approaches that focus only on a single spectral feature, such as simple linear regression using selected continuum-removed spectra values as a predictor variable, often provide accurate estimates. Furthermore, if this approach extends to multiple cases by taking into account three basic absorption feature parameters (area, width, and depth) of all occurring features as predictors and subjecting them to best subset selection, one can achieve even higher prediction accuracy compared with PLS regression. Here, we attempt to further extend this approach by adding two additional absorption feature parameters (left and right side area), as they can be important diagnostic markers, too. As a result, we achieved higher prediction accuracy compared with PLS regression and SVM for exchangeable soil pH, slightly higher or comparable for dithionite-citrate and ammonium oxalate extractable Fe and Mn forms, but slightly worse for oxidizable carbon content. Therefore, we suggest incorporating the multiple linear regression approach based on absorption feature parameters into existing working practices. PMID:26555184

  1. Absorption of Sunlight in Clear and Cloudy Atmospheres: A Solution to the Cloud Absorption Anomaly

    NASA Technical Reports Server (NTRS)

    Crisp, D.

    1997-01-01

    To identify the origin of this mission absorption, a spectrum-resolving (line-by-line) multiple scattering model was used to derive solar radiances, fluxes, and heating rates for realistic clear and cloudy atmospheres.

  2. Relic Neutrino Absorption Spectroscopy

    SciTech Connect

    Eberle, b

    2004-01-28

    Resonant annihilation of extremely high-energy cosmic neutrinos on big-bang relic anti-neutrinos (and vice versa) into Z-bosons leads to sizable absorption dips in the neutrino flux to be observed at Earth. The high-energy edges of these dips are fixed, via the resonance energies, by the neutrino masses alone. Their depths are determined by the cosmic neutrino background density, by the cosmological parameters determining the expansion rate of the universe, and by the large redshift history of the cosmic neutrino sources. We investigate the possibility of determining the existence of the cosmic neutrino background within the next decade from a measurement of these absorption dips in the neutrino flux. As a by-product, we study the prospects to infer the absolute neutrino mass scale. We find that, with the presently planned neutrino detectors (ANITA, Auger, EUSO, OWL, RICE, and SalSA) operating in the relevant energy regime above 10{sup 21} eV, relic neutrino absorption spectroscopy becomes a realistic possibility. It requires, however, the existence of extremely powerful neutrino sources, which should be opaque to nucleons and high-energy photons to evade present constraints. Furthermore, the neutrino mass spectrum must be quasi-degenerate to optimize the dip, which implies m{sub {nu}} 0.1 eV for the lightest neutrino. With a second generation of neutrino detectors, these demanding requirements can be relaxed considerably.

  3. Absorption Characteristics of Vertebrate Non-Visual Opsin, Opn3

    PubMed Central

    Sugihara, Tomohiro; Nagata, Takashi; Mason, Benjamin; Koyanagi, Mitsumasa; Terakita, Akihisa

    2016-01-01

    Most animals possess multiple opsins which sense light for visual and non-visual functions. Here, we show spectral characteristics of non-visual opsins, vertebrate Opn3s, which are widely distributed among vertebrates. We successfully expressed zebrafish Opn3 in mammalian cultured cells and measured its absorption spectrum spectroscopically. When incubated with 11-cis retinal, zebrafish Opn3 formed a blue-sensitive photopigment with an absorption maximum around 465 nm. The Opn3 converts to an all-trans retinal-bearing photoproduct with an absorption spectrum similar to the dark state following brief blue-light irradiation. The photoproduct experienced a remarkable blue-shift, with changes in position of the isosbestic point, during further irradiation. We then used a cAMP-dependent luciferase reporter assay to investigate light-dependent cAMP responses in cultured cells expressing zebrafish, pufferfish, anole and chicken Opn3. The wild type opsins did not produce responses, but cells expressing chimera mutants (WT Opn3s in which the third intracellular loops were replaced with the third intracellular loop of a Gs-coupled jellyfish opsin) displayed light-dependent changes in cAMP. The results suggest that Opn3 is capable of activating G protein(s) in a light-dependent manner. Finally, we used this assay to measure the relative wavelength-dependent response of cells expressing Opn3 chimeras to multiple quantally-matched stimuli. The inferred spectral sensitivity curve of zebrafish Opn3 accurately matched the measured absorption spectrum. We were unable to estimate the spectral sensitivity curve of mouse or anole Opn3, but, like zebrafish Opn3, the chicken and pufferfish Opn3-JiL3 chimeras also formed blue-sensitive pigments. These findings suggest that vertebrate Opn3s may form blue-sensitive G protein-coupled pigments. Further, we suggest that the method described here, combining a cAMP-dependent luciferase reporter assay with chimeric opsins possessing the third

  4. Clear evidence for the presence of O VI absorption in QSO metal systems

    NASA Technical Reports Server (NTRS)

    Lu, Limin; Savage, Blair D.

    1993-01-01

    We have detected O VI 1031.93 A, 1037.62 A doublet absorption in a composite QSO spectrum formed from a large number of intervening C IV absorption systems. The detections constitute the first firm evidence for the presence of O VI in intervening QSO metal absorption systems. The equivalent width of the detected O VI absorption implies an O VI column density N(O VI) not less than 2.8 x 10 exp 14/sq cm. This value, together with the nondetection of the N V 1238.82 A, 1242.80 A doublet absorption, suggests that N(O VI)/N(N V) not less than 4.4. For collisionally ionized gas with a solar O to N abundance ratio in thermal equilibrium the above ratio requires a temperature T not less than 2.5 x 10 exp 5 K. It is found that C IV systems which show low-ionization species and those which do not both have associated O VI absorption, suggesting that O VI is probably present in all C IV systems. We also find that C IV systems which show low-ionization species on average have stronger high-ionization absorption lines than those which do not. A simple interpretation was given to explain this trend.

  5. X-ray Absorption Studies in Spinel-Type LiMn 2O 4

    NASA Astrophysics Data System (ADS)

    Liu, R. S.; Jang, L. Y.; Chen, J. M.; Tsai, Y. C.; Hwang, Y. D.; Liu, R. G.

    1997-02-01

    The electronic structure of the spinel-type LiMn2O4as the cathode material for the application in secondary batteries was probed using both MnK- andL23-edge X-ray absorption near edge structure (XANES) spectra. Based on the energy shifts of the absorption peaks in the XANES spectrum correlated to the effective charge, the valence of Mn in LiMn2O4was determined to be ∼4+. This suggests that the chemical substitution of low valent Li+ions into the Mn sites is possible to result in high valence of Mn.

  6. Further advancement of differential optical absorption spectroscopy: theory of orthogonal optical absorption spectroscopy.

    PubMed

    Liudchik, Alexander M

    2014-08-10

    A modified version of the differential optical absorption spectroscopy (DOAS) method is presented. The technique is called orthogonal optical absorption spectroscopy (OOAS). A widespread variant of DOAS with smoothing of the registered spectrum and absorption cross sections being made employing a polynomial regression is a particular case of OOAS. The concept of OOAS provides a variety of new possibilities for constructing computational schemes and analyzing the influence of different error sources on calculated concentrations. PMID:25320931

  7. ABSORPTION ANALYZER

    DOEpatents

    Brooksbank, W.A. Jr.; Leddicotte, G.W.; Strain, J.E.; Hendon, H.H. Jr.

    1961-11-14

    A means was developed for continuously computing and indicating the isotopic assay of a process solution and for automatically controlling the process output of isotope separation equipment to provide a continuous output of the desired isotopic ratio. A counter tube is surrounded with a sample to be analyzed so that the tube is exactly in the center of the sample. A source of fast neutrons is provided and is spaced from the sample. The neutrons from the source are thermalized by causing them to pass through a neutron moderator, and the neutrons are allowed to diffuse radially through the sample to actuate the counter. A reference counter in a known sample of pure solvent is also actuated by the thermal neutrons from the neutron source. The number of neutrons which actuate the detectors is a function of a concentration of the elements in solution and their neutron absorption cross sections. The pulses produced by the detectors responsive to each neu tron passing therethrough are amplified and counted. The respective times required to accumulate a selected number of counts are measured by associated timing devices. The concentration of a particular element in solution may be determined by utilizing the following relation: T2/Ti = BCR, where B is a constant proportional to the absorption cross sections, T2 is the time of count collection for the unknown solution, Ti is the time of count collection for the pure solvent, R is the isotopic ratlo, and C is the molar concentration of the element to be determined. Knowing the slope constant B for any element and when the chemical concentration is known, the isotopic concentration may be readily determined, and conversely when the isotopic ratio is known, the chemical concentrations may be determined. (AEC)

  8. Decays of the Three Top Contributors to the Reactor ν[over ¯]_{e} High-Energy Spectrum, ^{92}Rb, ^{96gs}Y, and ^{142}Cs, Studied with Total Absorption Spectroscopy.

    PubMed

    Rasco, B C; Wolińska-Cichocka, M; Fijałkowska, A; Rykaczewski, K P; Karny, M; Grzywacz, R K; Goetz, K C; Gross, C J; Stracener, D W; Zganjar, E F; Batchelder, J C; Blackmon, J C; Brewer, N T; Go, S; Heffron, B; King, T; Matta, J T; Miernik, K; Nesaraja, C D; Paulauskas, S V; Rajabali, M M; Wang, E H; Winger, J A; Xiao, Y; Zachary, C J

    2016-08-26

    We report total absorption spectroscopy measurements of ^{92}Rb, ^{96gs}Y, and ^{142}Cs β decays, which are the most important contributors to the high energy ν[over ¯]_{e} spectral shape in nuclear reactors. These three β decays contribute 43% of the ν[over ¯]_{e} flux near 5.5 MeV emitted by nuclear reactors. This ν[over ¯]_{e} energy is particularly interesting due to spectral features recently observed in several experiments including the Daya Bay, Double Chooz, and RENO Collaborations. Measurements were conducted at Oak Ridge National Laboratory by means of proton-induced fission of ^{238}U with on-line mass separation of fission fragments and the Modular Total Absorption Spectrometer. We observe a β-decay pattern that is similar to recent measurements of ^{92}Rb, with a ground-state to ground-state β feeding of 91(3)%. We verify the ^{96gs}Y ground-state to ground-state β feeding of 95.5(20)%. Our measurements substantially modify the β-decay feedings of ^{142}Cs, reducing the β feeding to ^{142}Ba states below 2 MeV by 32% when compared with the latest evaluations. Our results increase the discrepancy between the observed and the expected reactor ν[over ¯]_{e} flux between 5 and 7 MeV, the maximum excess increases from ∼10% to ∼12%. PMID:27610847

  9. Slow light and saturable absorption

    NASA Astrophysics Data System (ADS)

    Selden, A. C.

    2009-06-01

    Quantitative analysis of slow light experiments utilising coherent population oscillation (CPO) in a range of saturably absorbing media, including ruby and alexandrite, Er3+:Y2SiO5, bacteriorhodopsin, semiconductor quantum devices and erbium-doped optical fibres, shows that the observations may be more simply interpreted as saturable absorption phenomena. A basic two-level model of a saturable absorber displays all the effects normally associated with slow light, namely phase shift and modulation gain of the transmitted signal, hole burning in the modulation frequency spectrum and power broadening of the spectral hole, each arising from the finite response time of the non-linear absorption. Only where hole-burning in the optical spectrum is observed (using independent pump and probe beams), or pulse delays exceeding the limits set by saturable absorption are obtained, can reasonable confidence be placed in the observation of slow light in such experiments. Superluminal (“fast light”) phenomena in media with reverse saturable absorption (RSA) may be similarly explained.

  10. Absorption, Creativity, Peak Experiences, Empathy, and Psychoticism.

    ERIC Educational Resources Information Center

    Mathes, Eugene W.; And Others

    Tellegen and Atkinson suggested that the trait of absorption may play a part in meditative skill, creativity, capacity for peak experiences, and empathy. Although the absorption-meditative skill relationship has been confirmed, other predictions have not been tested. Tellegen and Atkinson's Absorption Scale was completed by undergraduates in four…

  11. ADAPTATION IN ZINC ABSORPTION FROM WHOLE DIETS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Limited evidence suggests that humans increase zinc (Zn) absorption in response to low Zn intake. Aim: To assess human Zn absorption from whole diets varying in Zn content, and short-term adaptation to meet apparent Zn requirements. Method: Using 65Zn and whole body counting, Zn absorption by 83 hea...

  12. Impedance Characteristics of the Plasma Absorption Probe

    NASA Astrophysics Data System (ADS)

    Yamazawa, Yohei

    2009-10-01

    The plasma absorption probe (PAP) is a diagnostics for determination of spatially resolved electron density.footnotetextH. Kokura, et al., Jpn. J. Appl. Phys. 38 5262 (1999). PAP has attracted considerable interest because of its applicability in a reactive plasma. The simple structure of the probe allows us a robust measurement while the mechanism of the absorption is complicated and there are still some uncertainty.footnotetextM. Lapke, et al., Appl. Phys. Lett. 90, 121502 (2007) In this study, we focus on the frequency characteristics of the impedance instead of the absorption spectrum. An electromagnetic field simulation reveals that there is only one parallel resonance in the impedance characteristics even in a case there are many peaks in absorption spectrum. Thus, the impedance characteristics provide a clue to understanding the mechanism.

  13. Fission Spectrum

    DOE R&D Accomplishments Database

    Bloch, F.; Staub, H.

    1943-08-18

    Measurements of the spectrum of the fission neutrons of 25 are described, in which the energy of the neutrons is determined from the ionization produced by individual hydrogen recoils. The slow neutrons producing fission are obtained by slowing down the fast neutrons from the Be-D reaction of the Stanford cyclotron. In order to distinguish between fission neutrons and the remaining fast cyclotron neutrons both the cyclotron current and the pusle amplifier are modulated. A hollow neutron container, in which slow neutrons have a lifetime of about 2 milliseconds, avoids the use of large distances. This method results in much higher intensities than the usual modulation arrangement. The results show a continuous distribution of neutrons with a rather wide maximum at about 0.8 MV falling off to half of its maximum value at 2.0 MV. The total number of netrons is determined by comparison with the number of fission fragments. The result seems to indicate that only about 30% of the neutrons have energies below .8 MV. Various tests are described which were performed in order to rule out modification of the spectrum by inelastic scattering. Decl. May 4, 1951

  14. Temperature dependence of the HNO3 UV absorption cross sections

    NASA Technical Reports Server (NTRS)

    Burkholder, James B.; Talukdar, Ranajit K.; Ravishankara, A. R.; Solomon, Susan

    1993-01-01

    The temperature dependence of the HNO3 absorption cross sections between 240 and 360 K over the wavelength range 195 to 350 nm has been measured using a diode array spectrometer. Absorption cross sections were determined using both (1) absolute pressure measurements at 298 K and (2) a dual absorption cell arrangement in which the absorption spectrum at various temperatures is measured relative to the room temperature absorption spectrum. The HNO3 absorption spectrum showed a temperature dependence which is weak at short wavelengths but stronger at longer wavelengths which are important for photolysis in the lower stratosphere. The 298 K absorption cross sections were found to be larger than the values currently recommended for atmospheric modeling (DeMore et al., 1992). Our absorption cross section data are critically compared with the previous measurements of both room temperature and temperature-dependent absorption cross sections. Temperature-dependent absorption cross sections of HNO3 are recommended for use in atmospheric modeling. These temperature dependent HNO3 absorption cross sections were used in a two-dimensional dynamical-photochemical model to demonstrate the effects of the revised absorption cross sections on loss rate of HNO3 and the abundance of NO2 in the stratosphere.

  15. The Transit Transmission Spectrum of a Cold Gas Giant Planet

    NASA Astrophysics Data System (ADS)

    Dalba, Paul A.; Muirhead, Philip S.; Fortney, Jonathan J.; Hedman, Matthew M.; Nicholson, Philip D.; Veyette, Mark J.

    2015-12-01

    We use solar occultations observed by the Visual and Infrared Mapping Spectrometer on board the Cassini Spacecraft to extract the 1-5 μm transmission spectrum of Saturn, as if it were a transiting exoplanet. We detect absorption from methane, ethane, acetylene, aliphatic hydrocarbons, and possibly carbon monoxide, with peak-to-peak features of up to 90 parts-per-million despite the presence of ammonia clouds. We also find that atmospheric refraction, as opposed to clouds or haze, determines the minimum altitude that could be probed during mid-transit. Self-consistent exoplanet atmosphere models show good agreement with Saturn’s transmission spectrum but fail to reproduce a large absorption feature near 3.4 μm, likely caused by gaseous ethane and a C-H stretching mode of an unknown aliphatic hydrocarbon. This large feature is located in one of the Spitzer Space Telescope bandpasses and could alter interpretations of transmission spectra if not properly modeled. The large signal in Saturn’s transmission spectrum suggests that transmission spectroscopy of cold, long-period gaseous exoplanets should be possible with current and future observatories. Motivated by these results, we briefly consider the feasibility of using a survey to search for and characterize cold exoplanets that are analogous to Jupiter and Saturn utilizing a target-of-opportunity approach.

  16. High-resolution transmission spectrum of the Earth's atmosphere-seeing Earth as an exoplanet using a lunar eclipse

    NASA Astrophysics Data System (ADS)

    Yan, F.; Fosbury, R. A. E.; Petr-Gotzens, M. G.; Zhao, G.; Wang, W.; Wang, L.; Liu, Y.; Pallé, E.

    2015-04-01

    With the rapid developments in the exoplanet field, more and more terrestrial exoplanets are being detected. Characterizing their atmospheres using transit observations will become a key datum in the quest for detecting an Earth-like exoplanet. The atmospheric transmission spectrum of our Earth will be an ideal template for comparison with future exo-Earth candidates. By observing a lunar eclipse, which offers a similar configuration to that of an exoplanet transit, we have obtained a high-resolution and high signal-to-noise ratio (SNR) transmission spectrum of the Earth's atmosphere. This observation was performed with the High Resolution Spectrograph at Xinglong Station, China during the total lunar eclipse in December 2011. We compare the observed transmission spectrum with our atmospheric model, and determine the characteristics of the various atmospheric species in detail. In the transmission spectrum, O2, O3, O2 . O2, NO2 and H2O are detected, and their column densities are measured and compared with the satellites data. The visible Chappuis band of ozone produces the most prominent absorption feature, which suggests that ozone is a promising molecule for the future exo-Earth characterization. Due to the high resolution and high SNR of our spectrum, several novel details of the Earth atmosphere's transmission spectrum are presented. The individual O2 lines are resolved and O2 isotopes are clearly detected. Our new observations do not confirm the absorption features of Ca II or Na I which have been reported in previous lunar eclipse observations. However, features in these and some other strong Fraunhofer line positions do occur in the observed spectrum. We propose that these are due to a Raman-scattered component in the forward-scattered sunlight appearing in the lunar umbral spectrum. Water vapour absorption is found to be rather weak in our spectrum because the atmosphere we probed is relatively dry, which prompts us to discuss the detectability of water

  17. Evidence for Active Galactic Nucleus Feedback in the Broad Absorption Lines and Reddening of Mrk 231

    NASA Astrophysics Data System (ADS)

    Leighly, Karen M.; Terndrup, Donald M.; Baron, Eddie; Lucy, Adrian B.; Dietrich, Matthias; Gallagher, Sarah C.

    2014-06-01

    We present the first J-band spectrum of Mrk 231, which reveals a large He I* λ10830 broad absorption line with a profile similar to that of the well-known Na I broad absorption line. Combining this spectrum with optical and UV spectra from the literature, we show that the unusual reddening noted by Veilleux et al. is explained by a reddening curve like those previously used to explain low values of total-to-selective extinction in Type Ia supernovae. The nuclear starburst may be the origin and location of the dust. Spatially resolved emission in the broad absorption line trough suggests nearly full coverage of the continuum emission region. The broad absorption lines reveal higher velocities in the He I* lines (produced in the quasar-photoionized H II region) compared with the Na I and Ca II lines (produced in the corresponding partially ionized zone). Cloudy simulations show that a density increase is required between the H II and partially ionized zones to produce ionic column densities consistent with the optical and IR absorption line measurements and limits, and that the absorber lies ~100 pc from the central engine. These results suggest that the He I* lines are produced in an ordinary quasar BAL wind that impacts upon, compresses, and accelerates the nuclear starburst's dusty effluent (feedback in action), and the Ca II and Na I lines are produced in this dusty accelerated gas. This unusual circumstance explains the rarity of Na I absorption lines; without the compression along our line of sight, Mrk 231 would appear as an ordinary iron low-ionization, broad absorption line quasar.

  18. On the role of spatial position of bridged oxygen atoms as surface passivants on the ground-state gap and photo-absorption spectrum of silicon nano-crystals

    SciTech Connect

    Nazemi, Sanaz; Soleimani, Ebrahim Asl; Pourfath, Mahdi E-mail: pourfath@iue.tuwien.ac.at

    2015-11-28

    Silicon nano-crystals (NCs) are potential candidates for enhancing and tuning optical properties of silicon for optoelectronic and photo-voltaic applications. Due to the high surface-to-volume ratio, however, optical properties of NC result from the interplay of quantum confinement and surface effects. In this work, we show that both the spatial position of surface terminants and their relative positions have strong effects on NC properties as well. This is accomplished by investigating the ground-state HOMO-LUMO band-gap, the photo-absorption spectra, and the localization and overlap of HOMO and LUMO orbital densities for prototype ∼1.2 nm Si{sub 32–x}H{sub 42–2x}O{sub x} hydrogenated silicon NC with bridged oxygen atoms as surface terminations. It is demonstrated that the surface passivation geometry significantly alters the localization center and thus the overlap of frontier molecular orbitals, which correspondingly modifies the electronic and optical properties of NC.

  19. Spectrum allocations above 40 GHz

    NASA Technical Reports Server (NTRS)

    Katzenstein, W. E.; Moore, R. P.; Kimball, H. G.

    1981-01-01

    The 1979 World Administrative Radio Conference (WARC-79) revised the International Table of Frequency Allocations to reflect increased interest and activity in the region of the EM spectrum above 40 GHz. The total width of the spectrum allocated (235 GHz) in the region above 40 GHz indicates the extent of this new spectrum resource, made accessible by advances in the state-of-the-art of telecommunications equipment. There are some striking differences between the approach to allocation above and below 40 GHz. For example, there are not bands allocated exclusively. This reflects the characteristics of propagation and the small antenna beamwidths achievable at these frequencies. Attention is given to atmospheric window and absorption band limits, allocations to satellite services, allocations to scientific services, allocations to terrestrial services, the future refinement of the radio regulations above 40 GHz, and allocations of WARC-79 and frequency management.

  20. Menopause Hastens Aging, Studies Suggest

    MedlinePlus

    ... gov/news/fullstory_160079.html Menopause Hastens Aging, Studies Suggest Researchers found it boosted cellular aging by ... it, can speed aging in women, two new studies suggest. "For decades, scientists have disagreed over whether ...

  1. Pathways of iron absorption.

    PubMed

    Conrad, Marcel E; Umbreit, Jay N

    2002-01-01

    Iron is vital for all living organisms but excess iron can be lethal because it facilitates free radical formation. Thus iron absorption is carefully regulated to maintain an equilibrium between absorption and body loss of iron. In countries where meat is a significant part of the diet, most body iron is derived from dietary heme because heme binds few of the dietary chelators that bind inorganic iron. Uptake of heme into enterocytes occurs as a metalloporphyrin in an endosomal process. Intracellular iron is released from heme by heme oxygenase to enter plasma as inorganic iron. Ferric iron is absorbed via a beta(3) integrin and mobilferrin pathway (IMP) which is unshared with other nutritional metals. Ferrous iron uptake is facilitated by a DMT-1 pathway which is shared with manganese. In the iron deficient gut, large quantities of both mobilferrin and DMT-1 are found in goblet cells and intraluminal mucins suggesting that they are secreted with mucin into the intestinal lumen to bind iron to facilitate uptake by the cells. In the cytoplasm, IMP and DMT associate in a large protein complex called paraferritin which serves as a ferrireductase. Paraferritin solublizes iron binding proteins and reduces iron to make iron available for production of iron containing proteins such as heme. Iron uptake by intestinal absorptive cells is regulated by the iron concentration within the cell. Except in hemochromatosis it remains in equilibrium with total body stores via transferrin receptors on the basolateral membrane of absorptive cells. Increased intracellular iron either up-regulates or satiates iron binding proteins on regulatory proteins to alter their location in the intestinal mucosa. PMID:12547224

  2. Demonstrating Absorption Spectra Using Commercially Available Incandescent Light Bulbs

    NASA Astrophysics Data System (ADS)

    Birriel, Jennifer J.

    In introductory astronomy courses, I typically introduce the three types of spectra: continuous, absorption line, and emission line. It is standard practice to use an ordinary incandescent light bulb to demonstrate the production of a continuous spectrum, and gas discharge tubes to demonstrate the production of an emission line spectrum. The concept of an absorption spectrum is more difficult for students to grasp. A variety of commercially available light bulbs can be used to demonstrate absorption spectra. Here I discuss the use of specialty incandescent light bulbs to demonstrate the phenomenon of absorption of the continuous spectrum produced by a hot tungsten filament. The bulbs examined include the GE Reveal bulb, yellow anti-insect lights, colored party bulbs, and an incandescent "black light" bulb. The bulbs can be used in a lecture or laboratory setting.

  3. Optical absorption of dilute nitride alloys using self-consistent Green's function method

    NASA Astrophysics Data System (ADS)

    Seifikar, Masoud; O'Reilly, Eoin P.; Fahy, Stephen

    2014-01-01

    We have calculated the optical absorption for InGaNAs and GaNSb using the band anticrossing (BAC) model and a self-consistent Green's function (SCGF) method. In the BAC model, we include the interaction of isolated and pair N levels with the host matrix conduction and valence bands. In the SCGF approach, we include a full distribution of N states, with non-parabolic conduction and light-hole bands, and parabolic heavy-hole and spin-split-off bands. The comparison with experiments shows that the first model accounts for many features of the absorption spectrum in InGaNAs; including the full distribution of N states improves this agreement. Our calculated absorption spectra for GaNSb alloys predict the band edges correctly but show more features than are seen experimentally. This suggests the presence of more disorder in GaNSb alloys in comparison with InGaNAs.

  4. Measurement of transient gas flow parameters by diode laser absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Bolshov, M. A.; Kuritsyn, Yu A.; Liger, V. V.; Mironenko, V. R.; Nadezhdinskii, A. I.; Ponurovskii, Ya Ya; Leonov, S. B.; Yarantsev, D. A.

    2015-04-01

    An absorption spectrometer based on diode lasers is developed for measuring two-dimension maps of temperature and water vapour concentration distributions in the combustion zones of two mixing supersonic flows of fuel and oxidiser in the single run regime. The method of measuring parameters of hot combustion zones is based on detection of transient spectra of water vapour absorption. The design of the spectrometer considerably reduces the influence of water vapour absorption along the path of a sensing laser beam outside the burning chamber. The optical scheme is developed, capable of matching measurement results in different runs of mixture burning. A new algorithm is suggested for obtaining information about the mixture temperature by constructing the correlation functions of the experimental spectrum with those simulated from databases. A two-dimensional map of temperature distribution in a test chamber is obtained for the first time under the conditions of plasma-induced combusion of the ethylene - air mixture.

  5. Identification and Characterization of Visible Absorption Components in Aqueous Methylglyoxal-Ammonium Sulfate Mixtures

    NASA Astrophysics Data System (ADS)

    McGivern, W. S.; Allison, T. C.; Radney, J. G.; Zangmeister, C. D.

    2014-12-01

    The aqueous reaction of methylglyoxal (MG) with ammonium sulfate has been suggested as a source of atmospheric ``brown carbon.'' We have utilized high-performance liquid chromatography coupled to ultraviolet-visible spectroscopy and tandem mass spectrometry to study the products of this reaction at high concentrations. The overall product spectrum shows a large number of distinct components; however, the visible absorption from this mixture is derived a very small number of components. The largest contributor is an imine-substituted (C=N-H) product of aldol condensation/facile dehydration reaction between the parent MG and a hydrated product of the MG + ammonia reaction. The asymmetric nature of this compound relative to the aldol condensation of two MG results in a sufficiently large redshift of the UV absorption spectrum that absorption of visible radiation can occur in the long-wavelength tail. The simplicity of the imine products is a result of a strong bias toward ketimine products due to the extensive hydration of the aldehydic moiety in the parent in aqueous solution. In addition, a strong pH dependence of the absorption cross section was observed with significantly greater absorption under more basic conditions. We have performed time-dependent density functional theory calculations to evaluate the absorption spectra of all of the possible condensation products and their respective ions, and the results are consistent with the experimental observations. We have also observed smaller concentrations of other condensation products of the imine-substituted parent species that do not contribute significantly to the visible absorption but have not been previously discussed.

  6. Effects of backlight structure on absorption experiments

    SciTech Connect

    Iglesias, C A

    2004-11-08

    The impact of spectral details in the backlight of absorption spectroscopy experiments is considered. It is shown that experimentally unresolved structure in the backlight spectrum can introduce significant errors in the inferred transmission. Furthermore, it is shown that a valuable experimental procedure previously used to test the accuracy of the data fails to reveal these errors.

  7. Discovery of Broad Soft X-ray Absorption Lines from the Quasar Wind in PDS 456

    NASA Astrophysics Data System (ADS)

    Reeves, J. N.; Braito, V.; Nardini, E.; Behar, E.; O’Brien, P. T.; Tombesi, F.; Turner, T. J.; Costa, M. T.

    2016-06-01

    High-resolution soft X-ray spectroscopy of the prototype accretion disk wind quasar, PDS 456, is presented. Here, the XMM-Newton reflection grating spectrometer spectra are analyzed from the large 2013–2014 XMM-Newton campaign, consisting of five observations of approximately 100 ks in length. During the last observation (OBS. E), the quasar is at a minimum flux level, and broad absorption line (BAL) profiles are revealed in the soft X-ray band, with typical velocity widths of {σ }{{v}}˜ {{10,000}} km s‑1. During a period of higher flux in the third and fourth observations (OBS. C and D, respectively), a very broad absorption trough is also present above 1 keV. From fitting the absorption lines with models of photoionized absorption spectra, the inferred outflow velocities lie in the range ˜ 0.1{--}0.2c. The absorption lines likely originate from He and H-like neon and L-shell iron at these energies. A comparison with earlier archival data of PDS 456 also reveals a similar absorption structure near 1 keV in a 40 ks observation in 2001, and generally the absorption lines appear most apparent when the spectrum is more absorbed overall. The presence of the soft X-ray BALs is also independently confirmed by an analysis of the XMM-Newton EPIC spectra below 2 keV. We suggest that the soft X-ray absorption profiles could be associated with a lower ionization and possibly clumpy phase of the accretion disk wind, where the latter is known to be present in this quasar from its well-studied iron K absorption profile and where the wind velocity reaches a typical value of 0.3c.

  8. Contribution of organic carbon to wood smoke particulate matter absorption of solar radiation

    NASA Astrophysics Data System (ADS)

    Kirchstetter, T. W.; Thatcher, T. L.

    2012-02-01

    Spectroscopic analysis shows that 115 residential wood smoke-dominated particulate matter samples absorb light with strong spectral selectivity, consistent with prior work that has demonstrated that organic carbon (OC), in addition to black carbon (BC), appreciably absorbs solar radiation in the visible and ultraviolet spectral regions. Apportionment of light absorption yields the absorption Ångström exponent of the light absorbing OC in these samples, which ranges from 3.0 to 7.4 and averages 5.0, and indicates that OC and BC, respectively, would account for 14% and 86% of solar radiation absorbed by the wood smoke in the atmosphere (integrated over the solar spectrum from 300 to 2500 nm). OC would contribute 49% of the wood smoke particulate matter absorption of ultraviolet solar radiation at wavelengths below 400 nm. These results illustrate that BC is the dominant light absorbing particulate matter species in atmospheres burdened with residential wood smoke and OC absorption is secondary but not insignificant. Further, since biomass combustion generates a major portion of atmospheric particulate matter globally, these results suggest that OC absorption should be included when particulate matter effects on the radiative forcing of climate are considered, and that OC absorption may affect the ultraviolet actinic flux and thus tropospheric photochemistry.

  9. Autism Spectrum Disorders and Epigenetics

    ERIC Educational Resources Information Center

    Grafodatskaya, Daria; Chung, Brian; Szatmari, Peter; Weksberg, Rosanna

    2010-01-01

    Objective: Current research suggests that the causes of autism spectrum disorders (ASD) are multifactorial and include both genetic and environmental factors. Several lines of evidence suggest that epigenetics also plays an important role in ASD etiology and that it might, in fact, integrate genetic and environmental influences to dysregulate…

  10. Energy spectrum of C60 fullerene

    NASA Astrophysics Data System (ADS)

    Mironov, G. I.; Murzashev, A. I.

    2011-11-01

    The energy spectrum of the C60 fullerene has been calculated in terms of the Shubin-Vonsovskii-Hubbard model using an approximation of static fluctuations. Based on the spectrum, the optical absorption bands at 4.84, 5.88, and 6.30 eV observed experimentally have been successfully explained. It has been concluded that the model used is applicable for the calculation of the energy spectrum and the energy properties of other nanosystems, such as fullerenes of higher orders, carbon nanotubes, and grafen planes.

  11. ON NEUTRAL ABSORPTION AND SPECTRAL EVOLUTION IN X-RAY BINARIES

    SciTech Connect

    Miller, J. M.; Cackett, E. M.; Reis, R. C.

    2009-12-10

    Current X-ray observatories make it possible to follow the evolution of transient and variable X-ray binaries across a broad range in luminosity and source behavior. In such studies, it can be unclear whether evolution in the low-energy portion of the spectrum should be attributed to evolution in the source, or instead to evolution in neutral photoelectric absorption. Dispersive spectrometers make it possible to address this problem. We have analyzed a small but diverse set of X-ray binaries observed with the Chandra High Energy Transmission Grating Spectrometer across a range in luminosity and different spectral states. The column density in individual photoelectric absorption edges remains constant with luminosity, both within and across source spectral states. This finding suggests that absorption in the interstellar medium strongly dominates the neutral column density observed in spectra of X-ray binaries. Consequently, evolution in the low-energy spectrum of X-ray binaries should properly be attributed to evolution in the source spectrum. We discuss our results in the context of X-ray binary spectroscopy with current and future X-ray missions.

  12. Infra-red absorption lines by molecules in grain mantles

    NASA Astrophysics Data System (ADS)

    Hagen, W.; Allamandola, L. J.; Greenberg, J. M.

    1980-06-01

    The laboratory spectrum of a solid mixture of H2O, CO, CH3OH, and NH3 at a temperature of 10 K reproduces the shape and peak positions of interstellar features. It is shown that the broad absorption features evident in the MIR spectra of some astronomical objects associated with interstellar dust can be explained by absorptions of molecules in grain mantles.

  13. Two-dimensional probe absorption in coupled quantum dots

    NASA Astrophysics Data System (ADS)

    Liu, Ningwu; Zhang, Yan; Kang, Chengxian; Wang, Zhiping; Yu, Benli

    2016-07-01

    We investigate the two-dimensional (2D) probe absorption in coupled quantum dots. It is found that, due to the position-dependent quantum interference effect, the 2D optical absorption spectrum can be easily controlled via adjusting the system parameters. Thus, our scheme may provide some technological applications in solid-state quantum communication.

  14. THE 3 μm SPECTRUM OF JUPITER's IRREGULAR SATELLITE HIMALIA

    SciTech Connect

    Brown, M. E.; Rhoden, A. R. E-mail: Alyssa.Rhoden@jhuapl.edu

    2014-10-01

    We present a medium resolution spectrum of Jupiter's irregular satellite Himalia covering the critical 3 μm spectral region. The spectrum shows no evidence for aqueously altered phyllosilicates, as had been suggested from the tentative detection of a 0.7 μm absorption, but instead shows a spectrum strikingly similar to the C/CF type asteroid 52 Europa. 52 Europa is the prototype of a class of asteroids generally situated in the outer asteroid belt between less distant asteroids which show evidence for aqueous alteration and more distant asteroids which show evidence for water ice. The spectral match between Himalia and this group of asteroids is surprising and difficult to reconcile with models of the origin of the irregular satellites.

  15. Assessment of the action spectrum for photooxidation in full fat bovine milk.

    PubMed

    Wold, Jens Petter; Skaret, Josefine; Dalsgaard, Trine Kastrup

    2015-07-15

    The action spectrum for photooxidation in full fat bovine milk was measured. Samples of milk with air or argon in headspace were exposed to narrow wavelength bands of light in the range 400-700 nm. Photooxidation in terms of off-flavors was measured by a sensory panel, volatile compounds by headspace solid phase micro extraction (SPME-GC-MS), and photobleaching of photosensitizers in milk (riboflavin, protoporphyrin IX and a chlorophyllic compound) by front face fluorescence spectroscopy. The action spectrum deviated significantly from the absorption spectrum of milk. Significant oxidation was induced by wavelengths around 400 nm and 500-650 nm in milk with air in headspace. Argon in headspace gave significant oxidation also at 700 nm. It is suggested that protoporphyrin IX and chlorophyll are responsible for oxidation induced by wavelengths >500 nm, and that also riboflavin is contributing from 400 to 500 nm. PMID:25722140

  16. Autism Spectrum Disorder

    MedlinePlus

    ... Awards Enhancing Diversity Find People About NINDS NINDS Autism Spectrum Disorder Information Page Condensed from Autism Spectrum ... en Español Additional resources from MedlinePlus What is Autism Spectrum Disorder? Autistic disorder (sometimes called autism or ...

  17. The far ultraviolet reflection spectrum of Uranus - Results from the Voyager encounter

    NASA Technical Reports Server (NTRS)

    Yelle, Roger V.; Doose, Lyn R.; Mcconnell, John C.; Strobel, Darrell F.

    1989-01-01

    The present analysis of the 1250-1700 A region Uranus spectrum obtained by Voyager's US spectrometer characterizes these observation results as due primarily to solar light reflected from an H2 Rayleigh and Raman scattering atmosphere with small but measurable hydrocarbon absorption. The hydrocarbon abundances obtained are substantially lower than those at comparable levels of the Saturn or Jupiter atmospheres; it is suggested, in one-dimensional terms, that this is due to diffusive separation, in conjunction with photochemical depletion caused by a very low eddy-diffusion coefficient. Strong latitudinal variations in the hydrocarbon abundances are suggested in the subsolar, polar stratosphere.

  18. Far ultraviolet reflection spectrum of Uranus - Results from the Voyager encounter

    SciTech Connect

    Yelle, R.V.; Doose, L.R.; Mcconnell, J.C.; Strobel, D.F.

    1989-02-01

    The present analysis of the 1250-1700 A region Uranus spectrum obtained by Voyager's US spectrometer characterizes these observation results as due primarily to solar light reflected from an H2 Rayleigh and Raman scattering atmosphere with small but measurable hydrocarbon absorption. The hydrocarbon abundances obtained are substantially lower than those at comparable levels of the Saturn or Jupiter atmospheres; it is suggested, in one-dimensional terms, that this is due to diffusive separation, in conjunction with photochemical depletion caused by a very low eddy-diffusion coefficient. Strong latitudinal variations in the hydrocarbon abundances are suggested in the subsolar, polar stratosphere. 38 references.

  19. Broad spectrum bioactive sunscreens.

    PubMed

    Velasco, Maria Valéria Robles; Sarruf, Fernanda Daud; Salgado-Santos, Idalina Maria Nunes; Haroutiounian-Filho, Carlos Alberto; Kaneko, Telma Mary; Baby, André Rolim

    2008-11-01

    The development of sunscreens containing reduced concentration of chemical UV filters, even though, possessing broad spectrum effectiveness with the use of natural raw materials that improve and infer UV absorption is of great interest. Due to the structural similarities between polyphenolic compounds and organic UV filters, they might exert photoprotection activity. The objective of the present research work was to develop bioactive sunscreen delivery systems containing rutin, Passiflora incarnata L. and Plantago lanceolata extracts associated or not with organic and inorganic UV filters. UV transmission of the sunscreen delivery system films was performed by using diffuse transmittance measurements coupling to an integrating sphere. In vitro photoprotection efficacy was evaluated according to the following parameters: estimated sun protection factor (SPF); Boot's Star Rating category; UVA/UVB ratio; and critical wavelength (lambda(c)). Sunscreen delivery systems obtained SPF values ranging from 0.972+/-0.004 to 28.064+/-2.429 and bioactive compounds interacted with the UV filters positive and negatively. This behavior may be attributed to: the composition of the delivery system; the presence of inorganic UV filter and quantitative composition of the organic UV filters; and the phytochemical composition of the P. incarnata L. and P. lanceolata extracts. Among all associations of bioactive compounds and UV filters, we found that the broad spectrum sunscreen was accomplished when 1.68% (w/w) P. incarnata L. dry extract was in the presence of 7.0% (w/w) ethylhexyl methoxycinnamate, 2.0% (w/w) benzophenone-3 and 2.0% (w/w) TiO(2). It was demonstrated that this association generated estimated SPF of 20.072+/-0.906 and it has improved the protective defense against UVA radiation accompanying augmentation of the UVA/UVB ratio from 0.49 to 0.52 and lambda(c) from 364 to 368.6nm. PMID:18662760

  20. Deimos: A featureless asteroid-like spectrum

    NASA Technical Reports Server (NTRS)

    Grundy, W. M.; Fink, Uwe

    1991-01-01

    High quality CCD spectra were obtained of Deimos from 0.5 to 1.0 micron at a spectral resolution of 15A at the time of the 1988 Mars opposition. The data acquisition and reduction methods allowed the quantitative prevention of scattered light from Mars contaminating the spectra. Solar analog stars BS560, BS2007, and BS8931 were observed the same night to allow removal of telluric absorptions. The ratio spectrum of Deimos has a red slope, increasing in reflectance by a factor of approx. 50 pct. over the one octave wavelength interval observed. Other than this slope, the spectrum is remarkably featureless. The absence of absorption bands in the spectrum of Deimos is in marked contrast with the spectra of Martian surface materials. No trace of the Fe(2+) charge transfer absorption band around 1 micron is observed, which rules out the presence of significant quantities of minerals such as the pyroxenes or olivine at the surface of Deimos. The featureless red spectrum of Deimos appears to be consistent with a surface composition of fine grained carbonaceous chondrite type material. An analysis is presented of the spectrum of Deimos which makes use of the Hapke scattering surface model.

  1. 10 Suggestions for Enhancing Lecturing

    ERIC Educational Resources Information Center

    Heitzmann, Ray

    2010-01-01

    Criticism of the lecture method remains a staple of discussion and writing in academia--and most of the time it's deserved! Those interested in improving this aspect of their teaching might wish to consider some or all of the following suggestions for enhancing lectures. These include: (1) Lectures must start with a "grabber"; (2) Lectures must be…

  2. A study of a high resolution IUE spectrum of AM Canum Venaticorum

    NASA Technical Reports Server (NTRS)

    Solheim, J.-E.; Sion, E. M.

    1994-01-01

    We have obtained the first high resolution IUE spectrum of the helium-rich, cataclysmic variable star AM CVn. The spectrum is greatly underexposed, but we can still detect both wide and narrow line profiles. We report broad, shortward-shifted, P-Cygni-like absorption and in some cases emission lines in the far UV high ionization resonance lines of C, N, O, and Si, but the profiles are considerably disk/boundary layer outflows, absorption disk continuum light in H-rich CVs. The highest ionizations show evidence of a narrow jet or conical flow. For other, lower ionized lines, we find some evidence of a stellar origin. The broad He II (lambda 1640 A) absorption profile with blue shifted emission core has a remarkably similar overall structure to the He II (lambda 1640 A) broad absorption trough in the IUE spectrum of the prototypical cool DO white dwarf HZ 21. The sharp absorption lines seem most convincingly in the resonance doublets of N V (lambda 1238 A, lambda 1242 A) and C IV (lambda 1548 A, lambda 1550 A) and in He II (lambda 1640 A) exhibit a precise velocity coincidence. These sharp features are almost certainly due to circumbinary matter because they are obviously unaffected by the rapid orbital motion (or rapid stellar rotation) in this short period system during the long (9.3 hour) IUE echelle exposure. Our observations support an evolution through shell episodes of a close binary system which ends up with an expanding envelope as seen for HZ 21, and suggests one possible evolutionary channel for production of DOs (DBs).

  3. Evidence for active galactic nucleus feedback in the broad absorption lines and reddening of MRK 231 {sup ,}

    SciTech Connect

    Leighly, Karen M.; Baron, Eddie; Lucy, Adrian B.; Terndrup, Donald M.; Dietrich, Matthias; Gallagher, Sarah C.

    2014-06-20

    We present the first J-band spectrum of Mrk 231, which reveals a large He I* λ10830 broad absorption line with a profile similar to that of the well-known Na I broad absorption line. Combining this spectrum with optical and UV spectra from the literature, we show that the unusual reddening noted by Veilleux et al. is explained by a reddening curve like those previously used to explain low values of total-to-selective extinction in Type Ia supernovae. The nuclear starburst may be the origin and location of the dust. Spatially resolved emission in the broad absorption line trough suggests nearly full coverage of the continuum emission region. The broad absorption lines reveal higher velocities in the He I* lines (produced in the quasar-photoionized H II region) compared with the Na I and Ca II lines (produced in the corresponding partially ionized zone). Cloudy simulations show that a density increase is required between the H II and partially ionized zones to produce ionic column densities consistent with the optical and IR absorption line measurements and limits, and that the absorber lies ∼100 pc from the central engine. These results suggest that the He I* lines are produced in an ordinary quasar BAL wind that impacts upon, compresses, and accelerates the nuclear starburst's dusty effluent (feedback in action), and the Ca II and Na I lines are produced in this dusty accelerated gas. This unusual circumstance explains the rarity of Na I absorption lines; without the compression along our line of sight, Mrk 231 would appear as an ordinary iron low-ionization, broad absorption line quasar.

  4. Estimation of molar absorptivities and pigment sizes for eumelanin and pheomelanin using femtosecond transient absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Piletic, Ivan R.; Matthews, Thomas E.; Warren, Warren S.

    2009-11-01

    Fundamental optical and structural properties of melanins are not well understood due to their poor solubility characteristics and the chemical disorder present during biomolecular synthesis. We apply nonlinear transient absorption spectroscopy to quantify molar absorptivities for eumelanin and pheomelanin and thereby get an estimate for their average pigment sizes. We determine that pheomelanin exhibits a larger molar absorptivity at near IR wavelengths (750nm), which may be extended to shorter wavelengths. Using the molar absorptivities, we estimate that melanin pigments contain ˜46 and 28 monomer units for eumelanin and pheomelanin, respectively. This is considerably larger than the oligomeric species that have been recently proposed to account for the absorption spectrum of eumelanin and illustrates that larger pigments comprise a significant fraction of the pigment distribution.

  5. D-xylose absorption

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003606.htm D-xylose absorption To use the sharing features on this page, please enable JavaScript. D-xylose absorption is a laboratory test to determine ...

  6. The HI absorption "Zoo"

    NASA Astrophysics Data System (ADS)

    Geréb, K.; Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.

    2015-03-01

    We present an analysis of the H I 21 cm absorption in a sample of 101 flux-selected radio AGN (S1.4 GHz> 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). We detect H I absorption in 32 objects (30% of the sample). In a previous paper, we performed a spectral stacking analysis on the radio sources, while here we characterize the absorption spectra of the individual detections using the recently presented busy function. The H I absorption spectra show a broad variety of widths, shapes, and kinematical properties. The full width half maximum (FWHM) of the busy function fits of the detected H I lines lies in the range 32 km s-1absorption (FW20) lies in the range 63 km s-1 200 km s-1). We study the kinematical and radio source properties of each group, with the goal of identifying different morphological structures of H I. Narrow lines mostly lie at the systemic velocity and are likely produced by regularly rotating H I disks or gas clouds. More H I disks can be present among galaxies with lines of intermediate widths; however, the H I in these sources is more unsettled. We study the asymmetry parameter and blueshift/redshift distribution of the lines as a function of their width. We find a trend for which narrow profiles are also symmetric, while broad lines are the most asymmetric. Among the broadest lines, more lines appear blueshifted than redshifted, similarly to what was found by previous studies. Interestingly, symmetric broad lines are absent from the sample. We argue that if a profile is broad, it is also asymmetric and shifted relative to the systemic velocity because it is tracing unsettled H I gas. In particular, besides three of the broadest (up to FW20 = 825 km s-1

  7. Derivation of water vapour absorption cross-sections in the red region

    NASA Technical Reports Server (NTRS)

    Lal, M.; Chakrabarty, D. K.

    1994-01-01

    Absorption spectrum in 436 to 448 nm wavelength region gives NO2 and O3 column densities. This spectrum can also give H2O column density. The spectrum in the range of 655 to 667 nm contains absorption due to NO3 and H2O. Combining the absorption spectra in the wavelength ranges of 436 to 448 and 655 to 667 nm, water vapor absorption cross-sections in this range comes out to be of the order of 2.0 x 10(exp -24) cm(exp -2).

  8. Autism spectrum disorders

    PubMed Central

    Faras, Hadeel; Al Ateeqi, Nahed; Tidmarsh, Lee

    2010-01-01

    Pervasive developmental disorders are a group of neurodevelopmental disorders characterized by impairments in communication, reciprocal social interaction and restricted repetitive behaviors or interests. The term autism spectrum disorders (ASD) has been used to describe their variable presentation. Although the cause of these disorders is not yet known, studies strongly suggest a genetic basis with a complex mode of inheritance. More research is needed to explore environmental factors that could be contributing to the cause of these disorders. The occurrence of ASD has been increasing worldwide, with the most recent prevalence studies indicating that they are present in 6 per 1000 children. The objectives of this article are to provide physicians with relevant information needed to identify and refer children presenting with symptoms suggestive of ASDs to specialized centers early, and to make them feel comfortable in dealing with public concerns regarding controversial issues about the etiology and management of these disorders. PMID:20622347

  9. Cathodoluminescence Spectrum Imaging Software

    2011-04-07

    The software developed for spectrum imaging is applied to the analysis of the spectrum series generated by our cathodoluminescence instrumentation. This software provides advanced processing capabilities s such: reconstruction of photon intensity (resolved in energy) and photon energy maps, extraction of the spectrum from selected areas, quantitative imaging mode, pixel-to-pixel correlation spectrum line scans, ASCII, output, filling routines, drift correction, etc.

  10. Suggestions for Popularizing Civil Aviation

    NASA Technical Reports Server (NTRS)

    1926-01-01

    The public generally is taking very little interest in the progress of Civil Aviation, and the time has come to educate the public in aeronautics and to make them realize the far-reaching importance of air transport. Briefly, the whole problem resolves itself into discovering and applying means for bringing some of the many aspects and effects of civil aviation into the everyday lives of the public. The report suggests three principal groups of methods: (1) Bring aviation into daily contact with the public. (2) Bring the public into daily contact with aviation. (3) General publicity.

  11. Experimental determination of terahertz atmospheric absorption parameters

    NASA Astrophysics Data System (ADS)

    Slocum, David M.; Goyette, Thomas M.; Giles, Robert H.; Nixon, William E.

    2015-05-01

    The terahertz frequency regime is often used as the `chemical fingerprint' region of the electromagnetic spectrum since many molecules exhibit a dense selection of rotational and vibrational transitions. Water is a major component of the atmosphere and since it has a large dipole moment the propagation of terahertz radiation will be dominated by atmospheric effects. This study will present the results of high-­-resolution broadband measurements of the terahertz atmospheric absorption and detail the technique for directly measuring the pressure broadening coefficients, absolute absorption coefficients, line positions, and continuum effects. Differences between these measured parameters and those tabulated in HITRAN will be discussed. Once the water vapor absorption was characterized, the same technique was used to measure the line parameters for methanol, a trace gas of interest within Earth's atmosphere. Methanol has a dense absorption spectrum in the terahertz frequency region and is an important molecule in fields such as environmental monitoring, security, and astrophysics. The data obtained in the present study will be of immediate use for the remote sensing community, as it is uncommon to measure this many independent parameters as well as to measure the absolute absorption of the transitions. Current models rely on tabulated databases of calculated values for the line parameters measured in this study. Differences between the measured data and those in the databases will be highlighted and discussed.

  12. Revision of Suggested State Regulations.

    PubMed

    Winston, John P

    2016-02-01

    It is the mission of the Conference of Radiation Control Program Directors (CRCPD) to promote radiological health in all aspects and phases of implementation and to create a seamless and coherent regulatory structure across the United States. CRCPD currently has 25 committees charged with the development of Suggested State Regulations (SSRs) for everything from transportation and waste disposal to tanning and medical therapy. The SR-F Committee is responsible for the suggested regulations of the equipment and processes used in medical diagnostic and interventional x-ray procedures. Several states are required by law to adopt the SSR verbatim, making it vital that they are kept current. The current revision of SR-F brought together representatives from the state radiation control programs, the Food and Drug Administration, the American Association of Physicists in Medicine, American College of Radiology, and industry. Through the course of two meetings and multiple conference calls, the Committee finalized an updated draft. The CRCPD process for the development of SSR is well established and includes internal and external peer review, review by the state Director Members, approval by the Board of Directors, and concurrence from relevant federal agencies. Once final, an SSR allows a state radiation control program to proceed through the state's own regulatory process with a vetted set of regulations, making this difficult process more efficient and effective. PMID:26717174

  13. The infrared spectrum of M8 E - Evidence for circumstellar CO

    NASA Technical Reports Server (NTRS)

    Larson, H. P.; Fink, U.; Hofmann, R.

    1986-01-01

    High-resolution spectroscopic observations of the compact infrared source M8 E are reported in the region from 3 to 5 microns. Very prominent CO absorption lines are observed in the v = 1-0 band at 4.7 microns. The velocity width and rotational temperature suggest that this CO absorption occurs in a highly excited region. The high background continuum flux level and the prominent appearance of the CO features suggest that the CO line-forming region must be in front of the dust emission region. A blister model for M8 E, which places most of the dust continuum emission behind the source, satisfies this requirement. According to this picture, the observed circumstellar CO spectrum shows a high rotational temperature and a large velocity dispersion because of the combined effects of the strong stellar wind and possible shock heating near the dust zone as the wind encounters the ambient molecular cloud.

  14. Urbanicity and Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Lauritsen, Marlene B.; Astrup, Aske; Pedersen, Carsten Bøcker; Obel, Carsten; Schendel, Diana E.; Schieve, Laura; Yeargin-Allsopp, Marshalyn; Parner, Erik T.

    2014-01-01

    The etiology of autism spectrum disorders (ASD) is for the majority of cases unknown and more studies of risk factors are needed. Geographic variation in ASD occurrence has been observed, and urban residence has been suggested to serve as a proxy for etiologic and identification factors in ASD. We examined the association between urbanicity level…

  15. Temperature dependence of the absorption edge of vitreous silica

    NASA Technical Reports Server (NTRS)

    Bates, C. W., Jr.

    1976-01-01

    During an investigation of the optical properties of high-purity vitreous silica (fused quartz), which is being developed by NASA as a reflective and ablative heat shield, some interesting properties of theoretical and experimental nature have become apparent which otherwise may have remained unnoticed. Of particular interest for the NASA application is the shift of the absorption edge toward longer wavelengths with increasing temperature. The results of studies of this shift and of the spectral dependence of the absorption edge are summarized in the present paper. Plots of the absorption edge and the absorption spectrum of fused quartz vs temperature are given and discussed.

  16. Building false memories without suggestions.

    PubMed

    Foster, Jeffrey L; Garry, Maryanne

    2012-01-01

    People can come to remember doing things they have never done. The question we asked in this study is whether people can systematically come to remember performing actions they never really did, in the absence of any suggestion from the experimenter. People built LEGO vehicles, performing some steps but not others. For half the people, all the pieces needed to assemble each vehicle were laid out in order in front of them while they did the building; for the other half, the pieces were hidden from view. The next day, everyone returned for a surprise recognition test. People falsely and confidently remembered having carried out steps they did not; those who saw all the pieces while they built each vehicle were more likely to correctly remember performing steps they did perform but equally likely to falsely remember performing steps they did not. We explain our results using the source monitoring framework: People used the relationships between actions to internally generate the missing, related actions, later mistaking that information for genuine experience. PMID:22774684

  17. Excited-state absorption and third-order optical nonlinearities in symmetric π-electron organic molecules

    NASA Astrophysics Data System (ADS)

    Williams, G. R. J.

    1996-07-01

    Excited-State Absorption (ESA), Two-Photon Absorption (TPA) and the third-order polarizability γ(ω;ω,ω, - ω) have been investigated for a model dichloride derivative of a symmetrically substituted benzylidene analine (SBAC), using a multielectron configuration-interaction procedure. The calculations indicate that SBAC exhibits ESA across the visible region of the spectrum, but that it is not as extensive as for molecules such as the phthalocyanines. The magnitude of the third-order polarizability is dominated by resonance enhancement from a very strong A g → B u one-photon absorption. The calculated off-resonance value for γ(ω;ω,ω, - ω) suggests that SBAC is a potential candidate for ultrafast switching applications.

  18. The discovery of 50 minute periodic absorption events from 4U1915-05

    NASA Technical Reports Server (NTRS)

    White, N. E.; Swank, J. H.

    1981-01-01

    The steady flux from 4U1916-05 which undergoes periodic absorption dips every 50 minutes was demonstrated. This period represents the underlying orbital period of the system. It is suggested that variations in the depth and duration of these events are caused by a bulge in the edge of the accretion disk, at the point where the gas stream impacts the disk. The mass losing star in this system is probably a low mass white dwarf. The spectrum of the dips indicates that the metallicity of the absorbing material is at least a factor 17 below solar values.

  19. The compact structure of radio-loud broad absorption line quasars

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Jiang, D. R.; Wang, T. G.; Xie, F. G.

    2008-11-01

    We present the results of EVN+MERLIN very long baseline interferometry (VLBI) polarization observations of eight broad absorption line (BAL) quasars at 1.6 GHz, including four low-ionization BAL quasars (LoBALs) and four high-ionization BAL quasars (HiBALs) with either steep or flat spectra on Very Large Array (VLA) scales. Only one steep-spectrum source, J1122+3124, shows two-sided structure on the scale of 2 kpc. The other four steep-spectrum sources and three flat-spectrum sources display either an unresolved image or a core-jet structure on scales of less than 300 pc. In all cases, the marginally resolved core is the dominant radio component. Linear polarization in the cores has been detected in the range of a few to 10 per cent. Polarization, together with high brightness temperatures (from 2 × 109 to 5 × 1010K), suggests a synchrotron origin for the radio emission. There is no apparent difference in the radio morphologies or polarization between low-ionization and high-ionization BAL quasi-stellar objects (QSOs) or between flat- and steep-spectrum sources. We discuss the orientation of BAL QSOs with both flat and steep spectra, and consider a possible evolutionary scenario for BAL QSOs. In this scenario, BAL QSOs are probably a young population of radio sources that are compact steep spectrum or GHz peaked radio source analogues at the low end of radio power.

  20. Hypnosis, hypnotic suggestibility, memory, and involvement in films.

    PubMed

    Maxwell, Reed; Lynn, Steven Jay; Condon, Liam

    2015-05-01

    Our research extends studies that have examined the relation between hypnotic suggestibility and experiential involvement and the role of an hypnotic induction in enhancing experiential involvement (e.g., absorption) in engaging tasks. Researchers have reported increased involvement in reading (Baum & Lynn, 1981) and music-listening (Snodgrass & Lynn, 1989) tasks during hypnosis. We predicted a similar effect for film viewing: greater experiential involvement in an emotional (The Champ) versus a non-emotional (Scenes of Toronto) film. We tested 121 participants who completed measures of absorption and trait dissociation and the Harvard Group Scale of Hypnotic Susceptibility and then viewed the two films after either an hypnotic induction or a non-hypnotic task (i.e., anagrams). Experiential involvement varied as a function of hypnotic suggestibility and film clip. Highly suggestible participants reported more state depersonalization than less suggestible participants, and depersonalization was associated with negative affect; however, we observed no significant correlation between hypnotic suggestibility and trait dissociation. Although hypnosis had no effect on memory commission or omission errors, contrary to the hypothesis that hypnosis facilitates absorption in emotionally engaging tasks, the emotional film was associated with more commission and omission errors compared with the non-emotional film. PMID:25594911

  1. Spectrum of anomalous magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Giovannini, Massimo

    2016-05-01

    The equations of anomalous magnetohydrodynamics describe an Abelian plasma where conduction and chiral currents are simultaneously present and constrained by the second law of thermodynamics. At high frequencies the magnetic currents play the leading role, and the spectrum is dominated by two-fluid effects. The system behaves instead as a single fluid in the low-frequency regime where the vortical currents induce potentially large hypermagnetic fields. After deriving the physical solutions of the generalized Appleton-Hartree equation, the corresponding dispersion relations are scrutinized and compared with the results valid for cold plasmas. Hypermagnetic knots and fluid vortices can be concurrently present at very low frequencies and suggest a qualitatively different dynamics of the hydromagnetic nonlinearities.

  2. A spectrum of an extrasolar planet.

    PubMed

    Richardson, L Jeremy; Deming, Drake; Horning, Karen; Seager, Sara; Harrington, Joseph

    2007-02-22

    Of the over 200 known extrasolar planets, 14 exhibit transits in front of their parent stars as seen from Earth. Spectroscopic observations of the transiting planets can probe the physical conditions of their atmospheres. One such technique can be used to derive the planetary spectrum by subtracting the stellar spectrum measured during eclipse (planet hidden behind star) from the combined-light spectrum measured outside eclipse (star + planet). Although several attempts have been made from Earth-based observatories, no spectrum has yet been measured for any of the established extrasolar planets. Here we report a measurement of the infrared spectrum (7.5-13.2 microm) of the transiting extrasolar planet HD 209458b. Our observations reveal a hot thermal continuum for the planetary spectrum, with an approximately constant ratio to the stellar flux over this wavelength range. Superposed on this continuum is a broad emission peak centred near 9.65 microm that we attribute to emission by silicate clouds. We also find a narrow, unidentified emission feature at 7.78 microm. Models of these 'hot Jupiter' planets predict a flux peak near 10 microm, where thermal emission from the deep atmosphere emerges relatively unimpeded by water absorption, but models dominated by water fit the observed spectrum poorly. PMID:17314975

  3. Autism Spectrum Disorder

    MedlinePlus

    Autism spectrum disorder (ASD) is a neurological and developmental disorder that begins early in childhood and lasts throughout a ... and pervasive developmental disorders. It is called a "spectrum" disorder because people with ASD can have a ...

  4. Autism Spectrum Disorder (ASD)

    MedlinePlus

    ... spectrum disorder (ASD) is a group of developmental disabilities that can cause significant social, communication and behavioral ... for autism spectrum disorder (ASD) and other developmental disabilities. More E-mail Your Friends "Children with autism ...

  5. ABSORPTIONS IN THE VISIBLE OF PROTONATED PYRENE COLLISIONALLY COOLED TO 15 K

    SciTech Connect

    Hardy, F.-X.; Gause, O.; Rice, C. A.; Maier, J. P.

    2013-12-01

    Protonated polycyclic hydrocarbons have been added to the list of suggested carriers of diffuse interstellar absorptions. To test this proposition requires laboratory spectra measured under interstellar conditions, in particular with the rotational and vibrational degrees of freedom equilibrated to low temperatures. This has been achieved for protonated pyrene with absorption bands in the visible, using an ion trap and collisional cooling to ≈15 K. A two-photon excitation-dissociation scheme was employed to record the (1) {sup 1} A' ← X {sup 1} A' electronic spectrum on around 10{sup 5} ions per duty cycle. The origin band of the absorption spectrum of this relatively large polycyclic aromatic species with 27 atoms is located at 4858.86 Å. Two further comparably intense spectral features are present at 4834.48 and 4809.32 Å. This is one of the largest protonated aromatics studied in the gas phase and compared to astronomical observations; however, it is not a carrier of known diffuse interstellar bands.

  6. Observations of the spectrum of Jupiter from 1500 to 2000 A with the IUE

    NASA Astrophysics Data System (ADS)

    Owen, T.; Caldwell, J.; Rivolo, A. R.; Moore, V.; Lane, A. L.; Sagan, C.; Hunt, G. E.; Ponnamperuma, C.

    1980-02-01

    The paper examines the far-UV spectrum of Jupiter recorded by observations with the International Ultraviolet Explorer, noting that only the upper levels of the plant's atmosphere are sampled. It is shown that there are several absorptions caused by C2H2 and indications that NH3 may also be present at these altitudes. In addition, it is suggested that PH3 may also play a role as a continuum absorber, and a new upper limit of 5 x 10 to the -9 on H2S/H2 forbidden line ratio. It is concluded that these results are consistent with existing models for Jovian photochemistry and atmospheric structure.

  7. Observations of the spectrum of Jupiter from 1500 to 2000 A with the IUE

    NASA Technical Reports Server (NTRS)

    Owen, T.; Caldwell, J.; Rivolo, A. R.; Moore, V.; Lane, A. L.; Hunt, G.; Ponnamperuma, C.

    1980-01-01

    The paper examines the far-UV spectrum of Jupiter recorded by observations with the International Ultraviolet Explorer, noting that only the upper levels of the plant's atmosphere are sampled. It is shown that there are several absorptions caused by C2H2 and indications that NH3 may also be present at these altitudes. In addition, it is suggested that PH3 may also play a role as a continuum absorber, and a new upper limit of 5 x 10 to the -9 on H2S/H2 forbidden line ratio. It is concluded that these results are consistent with existing models for Jovian photochemistry and atmospheric structure.

  8. Absorption of Solar Radiation by Clouds: Observations Versus Models

    NASA Technical Reports Server (NTRS)

    Cess, R. D.; Zhang, M. H.; Minnis, P.; Corsetti, L.; Dutton, E. G.; Forgan, B. W.; Garber, D. P.; Gates, W. L.; Hack, J. J.; Harrison, E. F.; Jing, X.; Kiehl, J. T.; Long, C. N.; Morcrette, J.-J.; Potter, G. L.; Ramanathan, V.; Subasilar, B.; Whitlock, C. H.; Young, D. F.; Zhou, Y.

    1995-01-01

    There has been a long history of unexplained anomalous absorption of solar radiation by clouds. Collocated satellite and surface measurements of solar radiation at five geographically diverse locations showed significant solar absorption by clouds, resulting in about 25 watts per square meter more global-mean absorption by the cloudy atmosphere than predicted by theoretical models. It has often been suggested that tropospheric aerosols could increase cloud absorption. But these aerosols are temporally and spatially heterogeneous, whereas the observed cloud absorption is remarkably invariant with respect to season and location. Although its physical cause is unknown, enhanced cloud absorption substantially alters our understanding of the atmosphere's energy budget.

  9. The allocation of the radio spectrum

    NASA Astrophysics Data System (ADS)

    Jackson, C. L.

    1980-02-01

    The system of the radio spectrum (10 kHz-300 GHz) allocation is discussed in its technical, economic, and managerial aspects. Possible improvements to the system are considered, such as minimizing human management, establishing a single authority for the allocation of the spectrum, and stimulating a more efficient use of the spectrum with economic incentives. The 'anarchy band' concept, a system of dynamic allocation, is suggested as a means of replacing human management with electronic equipment. The growing importance of the satellite portion of the spectrum is also shown.

  10. Pressure-induced absorption coefficients for radiative transfer calculations in Titan's atmosphere

    NASA Technical Reports Server (NTRS)

    Courtin, Regis

    1988-01-01

    The semiempirical theory of Birnbaum and Cohen (1976) is used to calculate the FIR pressure-induced absorption (PIA) spectra of N2, CH4, N2 + Ar, N2 + CH4, and N2 + H2 under conditions like those in the Titan troposphere. The results are presented graphically and compared with published data from laboratory measurements of PIA in the same gases and mixtures (Dagg et al., 1986; Dore et al., 1986). Good agreement is obtained, with only a slight underestimation of PIA at 300-400/cm in the case of CH4. The absorption coefficients are presented in tables, and it is suggested that the present findings are of value for evaluating the effects of tropospheric clouds on the Titan FIR spectrum and studying the greenhouse effect near the Titan surface.

  11. On the bathochromic shift of the absorption by astaxanthin in crustacyanin: a quantum chemical study

    NASA Astrophysics Data System (ADS)

    Durbeej, Bo; Eriksson, Leif A.

    2003-06-01

    The structural origin of the bathochromic shift assumed by the electronic absorption spectrum of protein-bound astaxanthin, the carotenoid that upon binding to crustacyanin is responsible for the blue colouration of lobster shell, is investigated by means of quantum chemical methods. The calculations suggest that the bathochromic shift is largely due to one of the astaxanthin C4 keto groups being hydrogen-bonded to a histidine residue of the surrounding protein, and that the effect of this histidine is directly dependent on its protonation state. Out of the different methodologies (CIS, TD-DFT, and ZINDO/S) employed to calculate wavelengths of maximum absorption, the best agreement with experimental data is obtained using the semiempirical ZINDO/S method.

  12. UV nebular absorption in Eta Car and Weigelt D

    NASA Astrophysics Data System (ADS)

    Nielsen, K. E.; Vieira, G. L.; Gull, T. R.; Lindler, D. J.; Eta Car HST Treasury Team

    2003-12-01

    The high angular and high spectral resolution of the HST/STIS MAMA echelle mode, provide an unique means to distinguish the physical structures surrounding Eta Car. Observations are parts of the HST treasury program (K. Davidson P.I.) for monitoring variations over Eta Car's spectroscopic minimum. Nebular emission is present above and below the stellar spectrum which is about 0.03'' wide. We have extracted the nebular part of the central source spectrum and compared it with the spectrum of Weigelt D, located approximately 0.2'' Northwest of the central source. The spectra show significant similarities and our conclusions are two-fold. First, the radiation from the Wiegelt blobs give an unwanted contribution to the spectrum of the central source, which emphasizes the importance of using an extracted spectrum in a spectral analysis. Second, the Weigelt blobs have so far been assumed to produce a pure emission line spectrum. However, this comparison shows the presence of similar absorption structures previously observed in the spectrum of the central star (Gull et al., 2003, submitted ApJL). Two velocity structures at approximately -50 and -500 km/s, respectively, have been observed in the Weigelt D spectrum. We present identifications of the absorption structures to supplement the emission line work performed by T. Zethson (2000, PhD Thesis) and provide additional information regarding the geometry of the inner parts of the Eta Car nebula. The -50 km/s velocity component is similar to the absorption structure at -146 km/s observed in the spectrum of the central object. If these velocity systems are related, this implies that the absorption component is located close to the central parts of the nebular system.

  13. The Biokinetic Spectrum for Temperature.

    PubMed

    Corkrey, Ross; McMeekin, Tom A; Bowman, John P; Ratkowsky, David A; Olley, June; Ross, Tom

    2016-01-01

    We identify and describe the distribution of temperature-dependent specific growth rates for life on Earth, which we term the biokinetic spectrum for temperature. The spectrum has the potential to provide for more robust modeling in thermal ecology since any conclusions derived from it will be based on observed data rather than using theoretical assumptions. It may also provide constraints for systems biology model predictions and provide insights in physiology. The spectrum has a Δ-shape with a sharp peak at around 42°C. At higher temperatures up to 60°C there was a gap of attenuated growth rates. We found another peak at 67°C and a steady decline in maximum rates thereafter. By using Bayesian quantile regression to summarise and explore the data we were able to conclude that the gap represented an actual biological transition between mesophiles and thermophiles that we term the Mesophile-Thermophile Gap (MTG). We have not identified any organism that grows above the maximum rate of the spectrum. We used a thermodynamic model to recover the Δ-shape, suggesting that the growth rate limits arise from a trade-off between activity and stability of proteins. The spectrum provides underpinning principles that will find utility in models concerned with the thermal responses of biological processes. PMID:27088362

  14. The Biokinetic Spectrum for Temperature

    PubMed Central

    Corkrey, Ross; McMeekin, Tom A.; Bowman, John P.; Ratkowsky, David A.; Olley, June; Ross, Tom

    2016-01-01

    We identify and describe the distribution of temperature-dependent specific growth rates for life on Earth, which we term the biokinetic spectrum for temperature. The spectrum has the potential to provide for more robust modeling in thermal ecology since any conclusions derived from it will be based on observed data rather than using theoretical assumptions. It may also provide constraints for systems biology model predictions and provide insights in physiology. The spectrum has a Δ-shape with a sharp peak at around 42°C. At higher temperatures up to 60°C there was a gap of attenuated growth rates. We found another peak at 67°C and a steady decline in maximum rates thereafter. By using Bayesian quantile regression to summarise and explore the data we were able to conclude that the gap represented an actual biological transition between mesophiles and thermophiles that we term the Mesophile-Thermophile Gap (MTG). We have not identified any organism that grows above the maximum rate of the spectrum. We used a thermodynamic model to recover the Δ-shape, suggesting that the growth rate limits arise from a trade-off between activity and stability of proteins. The spectrum provides underpinning principles that will find utility in models concerned with the thermal responses of biological processes. PMID:27088362

  15. Percutaneous absorption in diseased skin: an overview.

    PubMed

    Chiang, Audris; Tudela, Emilie; Maibach, Howard I

    2012-08-01

    The stratum corneum's (SC) functions include protection from external hazardous environments, prevention of water loss and regulation of body temperature. While intact skin absorption studies are abundant, studies on compromised skin permeability are less common, although products are often used to treat affected skin. We reviewed literature on percutaneous absorption through abnormal skin models. Tape stripping is used to disrupt water barrier function. Studies demonstrated that physicochemical properties influence the stripping effect: water-soluble drugs are more affected. Abrasion did not affect absorption as much. Freezing is commonly used to preserve skin. It does not seem to modify water absorption, but still increases the penetration of compounds. Comparatively, heating the skin consistently increased percutaneous absorption. Removing SC lipids may increase percutaneous absorption of drugs. Many organic solvents are employed to delipidize. Delipidization with chloroform-methanol increased hydrophilic compound permeability, but not lipophilic. Acetone pre-treatment enhanced hydrophilic compound penetration. More data is needed to determine influence on highly lipophilic compound penetration. Sodium lauryl sulfate (SLS) induces irritant dermatitis and is frequently used as a model. Studies revealed that SLS increases hydrophilic compound absorption, but not lipophilic. However, skin irritation with other chemicals increases lipophilic penetration as much as hydrophilic. Animal studies show that UV exposure increases percutaneous absorption whereas human studies do not. Human studies show increased penetration in psoriatic and atopic dermatitis skin. The data summarized here begin to characterize flux alteration associated with damaged skin. Understanding the degree of alteration requires interpretation of involved conditions and the enlarging of our database to a more complete physicochemical spectrum. PMID:22912973

  16. Direct and quantitative broadband absorptance spectroscopy with multilayer cantilever probes

    SciTech Connect

    Hsu, Wei-Chun; Tong, Jonathan Kien-Kwok; Liao, Bolin; Chen, Gang

    2015-04-21

    A system for measuring the absorption spectrum of a sample is provided that includes a broadband light source that produces broadband light defined within a range of an absorptance spectrum. An interferometer modulates the intensity of the broadband light source for a range of modulation frequencies. A bi-layer cantilever probe arm is thermally connected to a sample arm having at most two layers of materials. The broadband light modulated by the interferometer is directed towards the sample and absorbed by the sample and converted into heat, which causes a temperature rise and bending of the bi-layer cantilever probe arm. A detector mechanism measures and records the deflection of the probe arm so as to obtain the absorptance spectrum of the sample.

  17. Solar absorption surface panel

    DOEpatents

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  18. Intestinal folate absorption

    PubMed Central

    Strum, Williamson; Nixon, Peter F.; Bertino, Joseph B.; Binder, Henry J.

    1971-01-01

    Intestinal absorption of the monoglutamate form of the principal dietary and circulating folate compound, 5-methyltetrahydrofolic acid (5-MTHF), was studied in the rat utilizing a synthetic highly purified radiolabeled diastereoisomer. Chromatography confirmed that the compound was not altered after transfer from the mucosa to the serosa. Accumulation against a concentration gradient was not observed in duodenal, jejunal, or ileal segments at 5-MTHF concentration from 0.5 to 500 nmoles/liter. Unidirectional transmural flux determination also did not indicate a significant net flux. Mucosal to serosal transfer of 5-MTHF was similar in all segments of the intestine and increased in a linear fashion with increased initial mucosal concentrations. Further, no alteration in 5-MTHF transfer was found when studied in the presence of metabolic inhibitors or folate compounds. These results indicate that 5-MTHF is not absorbed by the rat small intestine by a carrier-mediated system and suggest that 5-MTHF transfer most likely represents diffusion. Images PMID:5564397

  19. Absorption of vitamin A in children with ascariasis.

    PubMed

    Sivakumar, B; Reddy, V

    1975-05-01

    Absorption of labelled vitamin A was studied in normal children and in children with round-worm infestation. Absorption of the vitamin was significantly low in children with ascariasis. In two subjects, in whom the studies were repeated, absorption of vitamin A was significantly increased after antihelminthic treatment. These results suggest that ascariasis may aggravate vitamin A deficiency by interfering with the absorption of the vitamin. PMID:1152102

  20. Petawatt laser absorption bounded

    PubMed Central

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-01-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials. PMID:24938656

  1. Petawatt laser absorption bounded

    NASA Astrophysics Data System (ADS)

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-06-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials.

  2. Handedness in Children With Autism Spectrum Disorder.

    PubMed

    Knaus, Tracey A; Kamps, Jodi; Foundas, Anne L

    2016-04-01

    The left hemisphere is usually predominant in manual skills and language, suggesting a link between hand dominance and language. Studies of autism spectrum disorder show atypical handedness; however, few have examined language-handedness associations. Handedness, assessed by task performance, and standardized receptive and expressive language tests were completed in 110 autism spectrum disorder children (96 boys; M age = 8.3 years, SD = 3.8) and 45 typically developing children (37 boys; M age = 8.6 years, SD = 4.3), 3 to 17 years of age. The autism spectrum disorder group had a lower handedness score (was less strongly lateralized) than the control group. In the autism spectrum disorder group, there was a small effect of handedness on language; right-handers had better language than non-right-handers. Results suggest poorer language prognosis may be associated with left- or mixed-handedness in autism spectrum disorder. PMID:27166333

  3. A first-principle calculation of the XANES spectrum of Cu2+ in water

    NASA Astrophysics Data System (ADS)

    La Penna, G.; Minicozzi, V.; Morante, S.; Rossi, G. C.; Stellato, F.

    2015-09-01

    The progress in high performance computing we are witnessing today offers the possibility of accurate electron density calculations of systems in realistic physico-chemical conditions. In this paper, we present a strategy aimed at performing a first-principle computation of the low energy part of the X-ray Absorption Spectroscopy (XAS) spectrum based on the density functional theory calculation of the electronic potential. To test its effectiveness, we apply the method to the computation of the X-ray absorption near edge structure part of the XAS spectrum in the paradigmatic, but simple case of Cu2+ in water. In order to keep into account the effect of the metal site structure fluctuations in determining the experimental signal, the theoretical spectrum is evaluated as the average over the computed spectra of a statistically significant number of simulated metal site configurations. The comparison of experimental data with theoretical calculations suggests that Cu2+ lives preferentially in a square-pyramidal geometry. The remarkable success of this approach in the interpretation of XAS data makes us optimistic about the possibility of extending the computational strategy we have outlined to the more interesting case of molecules of biological relevance bound to transition metal ions.

  4. A first-principle calculation of the XANES spectrum of Cu{sup 2+} in water

    SciTech Connect

    La Penna, G.; Minicozzi, V.; Morante, S.; Stellato, F.; Rossi, G. C.

    2015-09-28

    The progress in high performance computing we are witnessing today offers the possibility of accurate electron density calculations of systems in realistic physico-chemical conditions. In this paper, we present a strategy aimed at performing a first-principle computation of the low energy part of the X-ray Absorption Spectroscopy (XAS) spectrum based on the density functional theory calculation of the electronic potential. To test its effectiveness, we apply the method to the computation of the X-ray absorption near edge structure part of the XAS spectrum in the paradigmatic, but simple case of Cu{sup 2+} in water. In order to keep into account the effect of the metal site structure fluctuations in determining the experimental signal, the theoretical spectrum is evaluated as the average over the computed spectra of a statistically significant number of simulated metal site configurations. The comparison of experimental data with theoretical calculations suggests that Cu{sup 2+} lives preferentially in a square-pyramidal geometry. The remarkable success of this approach in the interpretation of XAS data makes us optimistic about the possibility of extending the computational strategy we have outlined to the more interesting case of molecules of biological relevance bound to transition metal ions.

  5. Percutaneous absorption of drugs.

    PubMed

    Wester, R C; Maibach, H I

    1992-10-01

    The skin is an evolutionary masterpiece of living tissue which is the final control unit for determining the local and systemic availability of any drug which must pass into and through it. In vivo in humans, many factors will affect the absorption of drugs. These include individual biological variation and may be influenced by race. The skin site of the body will also influence percutaneous absorption. Generally, those body parts exposed to the open environment (and to cosmetics, drugs and hazardous toxic substances) are most affected. Treating patients may involve single daily drug treatment or multiple daily administration. Finally, the body will be washed (normal daily process or when there is concern about skin decontamination) and this will influence percutaneous absorption. The vehicle of a drug will affect release of drug to skin. On skin, the interrelationships of this form of administration involve drug concentration, surface area exposed, frequency and time of exposure. These interrelationships determine percutaneous absorption. Accounting for all the drug administered is desirable in controlled studies. The bioavailability of the drug then is assessed in relationship to its efficacy and toxicity in drug development. There are methods, both quantitative and qualitative, in vitro and in vivo, for studying percutaneous absorption of drugs. Animal models are substituted for humans to determine percutaneous absorption. Each of these methods thus becomes a factor in determining percutaneous absorption because they predict absorption in humans. The relevance of these predictions to humans in vivo is of intense research interest. The most relevant determination of percutaneous absorption of a drug in humans is when the drug in its approved formulation is applied in vivo to humans in the intended clinical situation. Deviation from this scenario involves the introduction of variables which may alter percutaneous absorption. PMID:1296607

  6. Demonstration That Calibration of the Instrument Response to Polarizations Parallel and Perpendicular to the Object Space Projected Slit of an Imaging Spectrometer Enable Measurement of the Atmospheric Absorption Spectrum in Region of the Weak CO2 Band for the Case of Arbitrary Polarization: Implication for the Geocarb Mission

    NASA Astrophysics Data System (ADS)

    Kumer, J. B.; Rairden, R. L.; Polonsky, I. N.; O'Brien, D. M.

    2014-12-01

    The Tropospheric Infrared Mapping Spectrometer (TIMS) unit rebuilt to operate in a narrow spectral region, approximately 1603 to 1615 nm, of the weak CO2 band as described by Kumer et al. (2013, Proc. SPIE 8867, doi:10.1117/12.2022668) was used to conduct the demonstration. An integrating sphere (IS), linear polarizers and quarter wave plate were used to confirm that the instrument's spectral response to unpolarized light, to 45° linearly polarized light and to circular polarized light are identical. In all these cases the intensity components Ip = Is where Ip is the component parallel to the object space projected slit and Is is perpendicular to the slit. In the circular polarized case Ip = Is in the time averaged sense. The polarizer and IS were used to characterize the ratio Rθ of the instrument response to linearly polarized light at the angle θ relative to parallel from the slit, for increments of θ from 0 to 90°, to that of the unpolarized case. Spectra of diffusely reflected sunlight passed through the polarizer in increments of θ, and divided by the respective Rθ showed identical results, within the noise limit, for solar spectrum multiplied by the atmospheric transmission and convolved by the Instrument Line Shape (ILS). These measurements demonstrate that unknown polarization in the diffusely reflected sunlight on this small spectral range affect only the slow change across the narrow band in spectral response relative to that of unpolarized light and NOT the finely structured / high contrast spectral structure of the CO2 atmospheric absorption that is used to retrieve the atmospheric content of CO2. The latter is one of the geoCARB mission objectives (Kumer et al, 2013). The situation is similar for the other three narrow geoCARB bands; O2 A band 757.9 to 768.6 nm; strong CO2 band 2045.0 to 2085.0 nm; CH4 and CO region 2300.6 to 2345.6 nm. Polonsky et al have repeated the mission simulation study doi:10.5194/amt-7-959-2014 assuming no use of a geo

  7. A near-infrared transmission spectrum for the warm Saturn HAT-P-12b

    SciTech Connect

    Line, Michael R.; Knutson, Heather; Desert, Jean-Michel; Deming, Drake; Wilkins, Ashlee

    2013-12-01

    We present a Hubble Space Telescope Wide Field Camera-3 (WFC3) transmission spectrum for the transiting exoplanet HAT-P-12b. This warm (1000 K) sub-Saturn-mass planet has a smaller mass and a lower temperature than the hot Jupiters that have been studied so far. We find that the planet's measured transmission spectrum lacks the expected water absorption feature for a hydrogen-dominated atmosphere and is instead best described by a model with high-altitude clouds. Using a frequentist hypothesis testing procedure, we can rule out a hydrogen-dominated cloud-free atmosphere to 4.9σ. When combined with other recent WFC3 studies, our observations suggest that clouds may be common in exoplanetary atmospheres.

  8. Zinc absorption in inflammatory bowel disease

    SciTech Connect

    Valberg, L.S.; Flanagan, P.R.; Kertesz, A.; Bondy, D.C.

    1986-07-01

    Zinc absorption was measured in 29 patients with inflammatory bowel disease and a wide spectrum of disease activity to determine its relationship to disease activity, general nutritional state, and zinc status. Patients with severe disease requiring either supplementary oral or parenteral nutrition were excluded. The mean 65ZnCl2 absorption, in the patients, determined using a 65Zn and 51Cr stool-counting test, 45 +/- 17% (SD), was significantly lower than the values, 54 +/- 16%, in 30 healthy controls, P less than 0.05. Low 65ZnCl2 absorption was related to undernutrition, but not to disease activity in the absence of undernutrition or to zinc status estimated by leukocyte zinc measurements. Mean plasma zinc or leukocyte zinc concentrations in patients did not differ significantly from controls, and only two patients with moderate disease had leukocyte zinc values below the 5th percentile of normal. In another group of nine patients with inflammatory bowel disease of mild-to-moderate severity and minimal nutritional impairment, 65Zn absorption from an extrinsically labeled turkey test meal was 31 +/- 10% compared to 33 +/- 7% in 17 healthy controls, P greater than 0.1. Thus, impairment in 65ZnCl2 absorption in the patients selected for this study was only evident in undernourished persons with moderate or severe disease activity, but biochemical evidence of zinc deficiency was uncommon, and clinical features of zinc depletion were not encountered.

  9. Electronic states of DNA and M-DNA studied by optical absorption

    NASA Astrophysics Data System (ADS)

    Tsuburaya, Makoto; Sakamoto, Hirokazu; Mizoguchi, Kenji

    2014-02-01

    To unveil the electronic states of divalent metal ion incorporated M-DNAs, where M is Mg, Mn, Ni, Co, or Fe, optical absorption spectra have been studied in aqueous solutions of single-stranded (SS) 30mer DNA of poly(dA) (adenine), poly(dG) (guanine), poly(dT) (thymine), poly(dC) (cytosine), salmon-sperm DNA (B-DNA), and M-DNA. The absorption spectrum of the double-stranded (DS) B-DNA can be reproduced with the sum of the four absorption spectra of the SS oligo-DNAs in the ratio corresponding to the composition of B-DNA. This observation suggests that the interactions between complementary strands of DS DNA are negligibly weaker than the bandwidths of the optical spectra. In the metal-incorporated M-DNAs, except for Fe-DNA, the absorption spectra show no significant qualitative change from that of B-DNA. Quantitatively, however, the absorption intensity decreases by ≈15% uniquely in a DS poly(dA)-poly(dT) solution with adding MCl2, while nothing happens quantitatively and qualitatively in any SS oligo-DNA and DS poly(dG)-poly(dC) solutions, suggesting some suppression of the electronic excitation only in the Adenine-M-Thymine complex. In contrast, remarkable differences have been observed in Fe-DNA, prepared with FeCl2 and B-DNA. New absorption bands appear in the intragap energy of Fe-DNA, in addition to the suppression of the interband absorption peak of DNA at 4.8 eV. The intragap absorption is attributed to the appearance of Fe3+ species with the same spectral feature as that of FeCl3, that is, purely ionic Fe3+ species. This observation suggests that FeCl2+B-DNA forms Fe-DNA with hydrated Fe3+ ions with ionic bonds. Thus, it is concluded that the charge transfer from Fe2+ to DNA has occurred in Fe-DNA and that the transferred charges are expected to be located in the nearby bases.

  10. Remote sensing of soot carbon - Part 2: Understanding the absorption Ångström exponent

    NASA Astrophysics Data System (ADS)

    Schuster, G. L.; Dubovik, O.; Arola, A.; Eck, T. F.; Holben, B. N.

    2016-02-01

    Recently, some authors have suggested that the absorption Ångström exponent (AAE) can be used to deduce the component aerosol absorption optical depths (AAODs) of carbonaceous aerosols in the AERONET database. This AAE approach presumes that AAE ≪ 1 for soot carbon, which contrasts the traditional small particle limit of AAE = 1 for soot carbon. Thus, we provide an overview of the AERONET retrieval, and we investigate how the microphysics of carbonaceous aerosols can be interpreted in the AERONET AAE product. We find that AAE ≪ 1 in the AERONET database requires large coarse mode fractions and/or imaginary refractive indices that increase with wavelength. Neither of these characteristics are consistent with the current definition of soot carbon, so we explore other possibilities for the cause of AAE ≪ 1. AAE is related to particle size, and coarse mode particles have a smaller AAE than fine mode particles for a given aerosol mixture of species. We also note that the mineral goethite has an imaginary refractive index that increases with wavelength, is very common in dust regions, and can easily contribute to AAE ≪ 1. We find that AAE ≪ 1 can not be caused by soot carbon, unless soot carbon has an imaginary refractive index that increases with wavelength throughout the visible and near-infrared spectrums. Finally, AAE is not a robust parameter for separating carbonaceous absorption from dust aerosol absorption in the AERONET database.

  11. The Optical Spectrum of the Geminga Pulsar

    NASA Technical Reports Server (NTRS)

    Martin, Christopher; Halpern, Jules P.; Schiminovich, David; Oliversen, Ronald (Technical Monitor)

    2001-01-01

    We obtained an optical spectrum of the isolated pulsar Geminga at the Keck Observatory. The optical object is at the limit of spectroscopic capability of any telescope, with a continuum flux that is approx. 0.5% of the dark sky on Mauna Kea. With particular attention paid to the dominant systematics of sky subtraction in our observing and analysis methods, we attained approx. 0.1% systematics in heavily binned spectra. The resulting spectrum spanning 3700 - 8000 A has a flat power-law shape f(sub nu) proportional to nu(exp -0.8) and a broad dip over 6300 - 6500 A. Thermal radiation cannot explain the optical spectrum of Geminga. The dominant component can be modeled as either electron synchrotron emission and ion (proton) cyclotron absorption, or ion cyclotron emission, the latter in a 10(exp 11) G magnetic field.

  12. Ultraviolet Continuum of the Quasar PKS 0405-123: Lyman Edge in the Accretion Disk Spectrum

    NASA Astrophysics Data System (ADS)

    Lee, G.; Kriss, G. A.; Davidsen, A. F.; Zheng, W.

    1995-05-01

    We study the characteristics of the ultraviolet continuum of the quasar PKS 0405-123 using the archival HST/FOS spectrum. The spectrum from 1150 to 3300 Angstroms shows a steeply rising continuum in F_λ with a strong absorption feature ~ 100 Angstroms wide around the intrinsic Lyman limit of this z=0.574 quasar. The spectrum also shows Lyman absorption line systems in the wavelength range of the broad absorption feature. A Lyalpha absorption line whose corresponding Lyman limit could contribute to the broad absorption feature is also identified. We investigate the possibility that the broad absorption feature may be due to the sum of the contributions from each Lyman absorption system. The estimated opacity due to the Lyman absorption systems in the region of the broad absorption feature, however, is not high enough to completely account for it. We thus propose that a significant part of the continuum drop in the broad absorption feature may be due to a broadened Lyman edge in the spectrum of an accretion disk. We model the ultraviolet continuum using an alpha -disk with an adiabatic vertical structure. We compute the emitted spectrum by solving the radiative transfer numerically. The observed spectrum is corrected for relativistic effects assuming a Schwarzschild metric, and we also consider the effect of Comptonization by a surrounding hot corona on the observed spectrum. A realistic disk spectrum with a significant amount of Comptonization describes the steep continuum shape and the broad Lyman edge feature, and it is consistent with the X-ray flux observed with EINSTEIN observatory IPC. This work was supported by NASA Grant NAG 5-1630 to the FOS team and NASA contract NAS 5-27000 to the Johns Hopkins University.

  13. Accelerating Spectrum Sharing Technologies

    SciTech Connect

    Juan D. Deaton; Lynda L. Brighton; Rangam Subramanian; Hussein Moradi; Jose Loera

    2013-09-01

    Spectrum sharing potentially holds the promise of solving the emerging spectrum crisis. However, technology innovators face the conundrum of developing spectrum sharing technologies without the ability to experiment and test with real incumbent systems. Interference with operational incumbents can prevent critical services, and the cost of deploying and operating an incumbent system can be prohibitive. Thus, the lack of incumbent systems and frequency authorization for technology incubation and demonstration has stymied spectrum sharing research. To this end, industry, academia, and regulators all require a test facility for validating hypotheses and demonstrating functionality without affecting operational incumbent systems. This article proposes a four-phase program supported by our spectrum accountability architecture. We propose that our comprehensive experimentation and testing approach for technology incubation and demonstration will accelerate the development of spectrum sharing technologies.

  14. Terahertz spectrum of gallic acid

    NASA Astrophysics Data System (ADS)

    Wu, Meng; Zhao, Guozhong; Wang, Haiyan; Liang, Chengshen

    2009-11-01

    Gallic acid is natural polyphenol compound found in many green plants. More and more experiments have demonstrated that the gallic acid has comprehensive applications. In the field of medicine, the gallic acid plays an important role in antianaphylaxis, antineoplastic, antimycotic, anti-inflammatory, antivirotic, antiasthmatic and inhibiting the degradation of insulin. It also has a lot of applications in chemical industry, food industry and light industry. So it is important to study the terahertz time-domain spectroscopy of gallic acid. Terahertz time-domain spectroscopy (THz-TDS) is a new coherent spectral technology based on the femtosecond laser. In this work, the spectral characteristics of gallic acid in the range of 0.4 THz to 2.6 THz have been measured by THz-TDS. We obtained its absorption and refraction spectra at room temperature. The vibration absorption spectrum of the single molecule between 0.4 THz and 2.6 THz is simulated based on the Density Functional Theory (DFT). It is found that the gallic acid has the spectral response to THz wave in this frequency range. The results show the abnormal dispersion at 1.51 THz and 2.05 THz. These results can be used in the qualitative analysis of gallic acid and the medicine and food inspection.

  15. The bispectrum of the Lyman α forest at z~ 2-2.4 from a large sample of UVES QSO absorption spectra (LUQAS)

    NASA Astrophysics Data System (ADS)

    Viel, M.; Matarrese, S.; Heavens, A.; Haehnelt, M. G.; Kim, T.-S.; Springel, V.; Hernquist, L.

    2004-01-01

    We present a determination of the bispectrum of the flux in the Lyman α forest of quasi-stellar object (QSO) absorption spectra obtained from a large sample of Ultraviolet Echelle Spectrograph (UVES) QSO absorption spectra (LUQAS), which consists of spectra observed with the high-resolution UVES. Typical errors on the observed bispectrum as obtained from a jack-knife estimator are ~ 50 per cent. For wavenumbers in the range 0.03 < k < 0.1 s km-1 the observed bispectrum agrees within the errors with that of the synthetic absorption spectra obtained from numerical hydro-simulations of a ΛCDM model with and without feedback from star formation. Including galactic feedback changes the bispectrum by less than 10 per cent. At smaller wavenumbers, the associated metal absorption lines contribute about 50 per cent to the bispectrum and the observed bispectrum exceeds that of the simulations. At wavenumbers k < 0.03 s km-1, second-order perturbation theory applied to the flux spectrum gives a reasonable (errors smaller than 30 per cent) approximation to the bispectra of observed and simulated absorption spectra. The bispectrum of the observed absorption spectra also agrees, within the errors, with that of a randomized set of absorption spectra where a random shift in wavelength has been added to absorption lines identified with VPFIT. This suggests that for a sample of the size presented here, the errors on the bispectrum are too large to discriminate between models with very different 3D distribution of Lyman α absorption. If it were possible to substantially reduce these errors for larger samples of absorption spectra, the bispectrum might become an important statistical tool for probing the growth of gravitational structure in the Universe at redshift z>~ 2.

  16. A Synthesis of Light Absorption Properties of the Arctic Ocean: Application to Semi-analytical Estimates of Dissolved Organic Carbon Concentrations from Space

    NASA Technical Reports Server (NTRS)

    Matsuoka, A.; Babin, M.; Doxaran, D.; Hooker, S. B.; Mitchell, B. G.; Belanger, S.; Bricaud, A.

    2014-01-01

    The light absorption coefficients of particulate and dissolved materials are the main factors determining the light propagation of the visible part of the spectrum and are, thus, important for developing ocean color algorithms. While these absorption properties have recently been documented by a few studies for the Arctic Ocean [e.g., Matsuoka et al., 2007, 2011; Ben Mustapha et al., 2012], the datasets used in the literature were sparse and individually insufficient to draw a general view of the basin-wide spatial and temporal variations in absorption. To achieve such a task, we built a large absorption database at the pan-Arctic scale by pooling the majority of published datasets and merging new datasets. Our results showed that the total non-water absorption coefficients measured in the Eastern Arctic Ocean (EAO; Siberian side) are significantly higher 74 than in the Western Arctic Ocean (WAO; North American side). This higher absorption is explained 75 by higher concentration of colored dissolved organic matter (CDOM) in watersheds on the Siberian 76 side, which contains a large amount of dissolved organic carbon (DOC) compared to waters off 77 North America. In contrast, the relationship between the phytoplankton absorption (a()) and chlorophyll a (chl a) concentration in the EAO was not significantly different from that in the WAO. Because our semi-analytical CDOM absorption algorithm is based on chl a-specific a() values [Matsuoka et al., 2013], this result indirectly suggests that CDOM absorption can be appropriately erived not only for the WAO but also for the EAO using ocean color data. Derived CDOM absorption values were reasonable compared to in situ measurements. By combining this algorithm with empirical DOC versus CDOM relationships, a semi-analytical algorithm for estimating DOC concentrations for coastal waters at the Pan-Arctic scale is presented and applied to satellite ocean color data.

  17. Absorption Features in Spectra of Magnetized Neutron Stars

    SciTech Connect

    Suleimanov, V.; Hambaryan, V.; Neuhaeuser, R.; Potekhin, A. Y.; Pavlov, G. G.; Adelsberg, M. van; Werner, K.

    2011-09-21

    The X-ray spectra of some magnetized isolated neutron stars (NSs) show absorption features with equivalent widths (EWs) of 50-200 eV, whose nature is not yet well known.To explain the prominent absorption features in the soft X-ray spectra of the highly magnetized (B{approx}10{sup 14} G) X-ray dim isolated NSs (XDINSs), we theoretically investigate different NS local surface models, including naked condensed iron surfaces and partially ionized hydrogen model atmospheres, with semi-infinite and thin atmospheres above the condensed surface. We also developed a code for computing light curves and integral emergent spectra of magnetized neutron stars with various temperature and magnetic field distributions over the NS surface. We compare the general properties of the computed and observed light curves and integral spectra for XDINS RBS 1223 and conclude that the observations can be explained by a thin hydrogen atmosphere above the condensed iron surface, while the presence of a strong toroidal magnetic field component on the XDINS surface is unlikely.We suggest that the harmonically spaced absorption features in the soft X-ray spectrum of the central compact object (CCO) 1E 1207.4-5209 (hereafter 1E 1207) correspond to peaks in the energy dependence of the free-free opacity in a quantizing magnetic field, known as quantum oscillations. To explore observable properties of these quantum oscillations, we calculate models of hydrogen NS atmospheres with B{approx}10{sup 10}-10{sup 11} G(i.e., electron cyclotron energy E{sub c,e}{approx}0.1-1 keV) and T{sub eff} = 1-3 MK. Such conditions are thought to be typical for 1E 1207. We show that observable features at the electron cyclotron harmonics with EWs {approx_equal}100-200 eV can arise due to these quantum oscillations.

  18. Time-dependent oral absorption models

    NASA Technical Reports Server (NTRS)

    Higaki, K.; Yamashita, S.; Amidon, G. L.

    2001-01-01

    The plasma concentration-time profiles following oral administration of drugs are often irregular and cannot be interpreted easily with conventional models based on first- or zero-order absorption kinetics and lag time. Six new models were developed using a time-dependent absorption rate coefficient, ka(t), wherein the time dependency was varied to account for the dynamic processes such as changes in fluid absorption or secretion, in absorption surface area, and in motility with time, in the gastrointestinal tract. In the present study, the plasma concentration profiles of propranolol obtained in human subjects following oral dosing were analyzed using the newly derived models based on mass balance and compared with the conventional models. Nonlinear regression analysis indicated that the conventional compartment model including lag time (CLAG model) could not predict the rapid initial increase in plasma concentration after dosing and the predicted Cmax values were much lower than that observed. On the other hand, all models with the time-dependent absorption rate coefficient, ka(t), were superior to the CLAG model in predicting plasma concentration profiles. Based on Akaike's Information Criterion (AIC), the fluid absorption model without lag time (FA model) exhibited the best overall fit to the data. The two-phase model including lag time, TPLAG model was also found to be a good model judging from the values of sum of squares. This model also described the irregular profiles of plasma concentration with time and frequently predicted Cmax values satisfactorily. A comparison of the absorption rate profiles also suggested that the TPLAG model is better at prediction of irregular absorption kinetics than the FA model. In conclusion, the incorporation of a time-dependent absorption rate coefficient ka(t) allows the prediction of nonlinear absorption characteristics in a more reliable manner.

  19. Terbium chloride--aluminum chloride vapor system. I. Absorption and excitation spectra

    SciTech Connect

    Caird, J.A.; Carnall, W.T.; Hessler, J.P.; Williams, C.W.

    1981-01-15

    The absorption spectrum of the vapor complex formed at elevated temperatures between TbCl/sub 3/ and AlCl/sub 3/ has been measured in the region 20 000--50 000 cm/sup -1/. Oscillator strengths of f--f absorption bands below 37 000 cm/sup -1/ were determined. Strong absorption due to opposite parity 4f/sup 7/5d states was observed in the 37 000 to 50 000 cm/sup -1/ region with a peak molar absorptivity of approximately 500 l/mol cm. Significant additional absorption attributed to a molecular complex was also observed in this region. By measuring the excitation spectrum it was found that the molecular absorption does not appear to lead to fluorescence of the /sup 5/D/sub 4/ state. In contrast, absorption by the 4f/sup 7/5d states does result in strong /sup 5/D/sub 4/ fluorescence.

  20. Compounds affecting cholesterol absorption

    NASA Technical Reports Server (NTRS)

    Hua, Duy H. (Inventor); Koo, Sung I. (Inventor); Noh, Sang K. (Inventor)

    2004-01-01

    A class of novel compounds is described for use in affecting lymphatic absorption of cholesterol. Compounds of particular interest are defined by Formula I: ##STR1## or a pharmaceutically acceptable salt thereof.

  1. Absorption heat pump system

    DOEpatents

    Grossman, Gershon

    1984-01-01

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  2. Absorption heat pump system

    DOEpatents

    Grossman, G.

    1982-06-16

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  3. Absorption spectra and photolysis of methyl peroxide in liquid and frozen water.

    PubMed

    Epstein, Scott A; Shemesh, Dorit; Tran, Van T; Nizkorodov, Sergey A; Gerber, R Benny

    2012-06-21

    Methyl peroxide (CH(3)OOH) is commonly found in atmospheric waters and ices in significant concentrations. It is the simplest organic peroxide and an important precursor to hydroxyl radical. Many studies have examined the photochemical behavior of gaseous CH(3)OOH; however, the photochemistry of liquid and frozen water solutions is poorly understood. We present a series of experiments and theoretical calculations designed to elucidate the photochemical behavior of CH(3)OOH dissolved in liquid water and ice over a range of temperatures. The molar extinction coefficients of aqueous CH(3)OOH are different from the gas phase, and they do not change upon freezing. Between -12 and 43 °C, the quantum yield of CH(3)OOH photolysis is described by the following equation: Φ(T) = exp((-2175 ± 448)1/T) + 7.66 ± 1.56). We use on-the-fly ab initio molecular dynamics simulations to model structures and absorption spectra of a bare CH(3)OOH molecule and a CH(3)OOH molecule immersed inside 20 water molecules at 50, 200, and 220 K. The simulations predict large sensitivity in the absorption spectrum of CH(3)OOH to temperature, with the spectrum narrowing and shifting to the blue under cryogenic conditions because of constrained dihedral motion around the O-O bond. The shift in the absorption spectrum is not observed in the experiment when the CH(3)OOH solution is frozen suggesting that CH(3)OOH remains in a liquid layer between the ice grains. Using the extinction coefficients and photolysis quantum yields obtained in this work, we show that under conditions with low temperatures, in the presence of clouds with a high liquid-water content and large solar zenith angles, the loss of CH(3)OOH by aqueous photolysis is responsible for up to 20% of the total loss of CH(3)OOH due to photolysis. Gas phase photolysis of CH(3)OOH dominates under all other conditions. PMID:22217262

  4. Optical absorption measurement system

    DOEpatents

    Draggoo, Vaughn G.; Morton, Richard G.; Sawicki, Richard H.; Bissinger, Horst D.

    1989-01-01

    The system of the present invention contemplates a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature.

  5. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2004-08-31

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  6. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2003-10-14

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  7. Optical absorption of several nanostructures arrays for silicon solar cells

    NASA Astrophysics Data System (ADS)

    Xu, Zhaopeng; Qiao, Huiling; Huangfu, Huichao; Li, Xiaowei; Guo, Jingwei; Wang, Haiyan

    2015-12-01

    To improve the efficiency and reduce the cost of solar cells, it's important to enhance the light absorption. Within the visible solar spectrum based on optimization simulations by COMSOL Multiphysics, the optical absorption of silicon cylindrical nanowires, nanocones and inverted nanocones was calculated respectively. The results reveal that the average absorption for the nanocones between 400 and 800 nm is 70.2%, which is better than cylindrical nanowires (55.3%), inverted nanocones (42.3%) and bulk silicon (42.2%). In addition, more than 95% of light from 630 to 800 nm is reflected for inverted nanocones, which can be used to enhance infrared reflection in photovoltaic devices.

  8. Emission from water vapor and absorption from other gases at 5-7.5 μm in Spitzer-IRS Spectra Of Protoplanetary Disks

    SciTech Connect

    Sargent, B. A.; Forrest, W.; Watson, Dan M.; Kim, K. H.; Richter, I.; Tayrien, C.; D'Alessio, P.; Calvet, N.; Furlan, E.; Green, J.; Pontoppidan, K.

    2014-09-10

    We present spectra of 13 T Tauri stars in the Taurus-Auriga star-forming region showing emission in Spitzer Space Telescope Infrared Spectrograph 5-7.5 μm spectra from water vapor and absorption from other gases in these stars' protoplanetary disks. Seven stars' spectra show an emission feature at 6.6 μm due to the ν{sub 2} = 1-0 bending mode of water vapor, with the shape of the spectrum suggesting water vapor temperatures >500 K, though some of these spectra also show indications of an absorption band, likely from another molecule. This water vapor emission contrasts with the absorption from warm water vapor seen in the spectrum of the FU Orionis star V1057 Cyg. The other 6 of the 13 stars have spectra showing a strong absorption band, peaking in strength at 5.6-5.7 μm, which for some is consistent with gaseous formaldehyde (H{sub 2}CO) and for others is consistent with gaseous formic acid (HCOOH). There are indications that some of these six stars may also have weak water vapor emission. Modeling of these stars' spectra suggests these gases are present in the inner few AU of their host disks, consistent with recent studies of infrared spectra showing gas in protoplanetary disks.

  9. Sensory Over-Responsivity in Adults with Autism Spectrum Conditions

    ERIC Educational Resources Information Center

    Tavassoli, Teresa; Miller, Lucy J.; Schoen, Sarah A.; Nielsen, Darci M.; Baron-Cohen, Simon

    2014-01-01

    Anecdotal reports and empirical evidence suggest that sensory processing issues are a key feature of autism spectrum conditions. This study set out to investigate whether adults with autism spectrum conditions report more sensory over-responsivity than adults without autism spectrum conditions. Another goal of the study was to identify whether…

  10. Absorption Measure Distribution in Mrk 509

    NASA Astrophysics Data System (ADS)

    Adhikari, T. P.; Różańska, A.; Sobolewska, M.; Czerny, B.

    2015-12-01

    In this paper we model the observed absorption measure distribution (AMD) in Mrk 509, which spans three orders of magnitude in ionization level with a single-zone absorber in pressure equilibrium. AMD is usually constructed from observations of narrow absorption lines in radio-quiet active galaxies with warm absorbers. We study the properties of the warm absorber in Mrk 509 using recently published broadband spectral energy distribution observed with different instruments. This spectrum is an input in radiative transfer computations with full photoionization treatment using the titan code. We show that the simplest way to fully reproduce the shape of AMD is to assume that the warm absorber is a single zone under constant total pressure. With this assumption, we found theoretical AMD that matches the observed AMD determined on the basis of the 600 ks reflection grating spectrometer XMM-Newton spectrum of Mrk 509. The softness of the source spectrum and the important role of the free-free emission breaks the usual degeneracy in the ionization state calculations, and the explicit dependence of the depths of AMD dips on density open a new path to the density diagnostic for the warm absorber. In Mrk 509, the implied density is of the order of 108 cm-3.

  11. Visible-absorption spectroscopy as a biomarker to predict treatment response and prognosis of surgically resected esophageal cancer.

    PubMed

    Yang, Pei-Wen; Hsu, I-Jen; Chang, Chun-Wei; Wang, Yu-Chia; Hsieh, Ching-Yueh; Shih, Kuan-Hui; Wong, Li-Fan; Shih, Nai-Yu; Hsieh, Min-Shu; Hou, Max Ti-Kuang; Lee, Jang-Ming

    2016-01-01

    The application of optical absorption spectra in prognostic prediction has hardly been investigated. We developed and evaluated a novel two dimensional absorption spectrum measurement system (TDAS) for use in early diagnosis, evaluating response to chemoradiation, and making prognostic prediction. The absorption spectra of 120 sets of normal and tumor tissues from esophageal cancer patients were analyzed with TDAS ex-vivo. We demonstrated the cancerous tissue, the tissue from patients with a poor concurrent chemoradiotherapy (CCRT) response, and the tissue from patients with an early disease progression each had a readily identifiable common spectral signature. Principal component analysis (PCA) classified tissue spectra into distinct groups, demonstrating the feasibility of using absorption spectra in differentiating normal and tumor tissues, and in predicting CCRT response, poor survival and tumor recurrence (efficiencies of 75%, 100% and 85.7% respectively). Multivariate analysis revealed that patients identified as having poor-response, poor-survival and recurrence spectral signatures were correlated with increased risk of poor response to CCRT (P = 0.012), increased risk of death (P = 0.111) and increased risk of recurrence (P = 0.030) respectively. Our findings suggest that optical absorption microscopy has great potential to be a useful tool for pre-operative diagnosis and prognostic prediction of esophageal cancer. PMID:27624872

  12. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, Robert C.; Biermann, Wendell J.

    1989-01-01

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit.

  13. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, R.C.; Biermann, W.J.

    1989-05-09

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit. 1 fig.

  14. Absorption of surface acoustic waves by topological insulator thin films

    SciTech Connect

    Li, L. L.; Xu, W.

    2014-08-11

    We present a theoretical study on the absorption of the surface acoustic waves (SAWs) by Dirac electrons in topological insulator (TI) thin films (TITFs). We find that due to momentum and energy conservation laws, the absorption of the SAWs in TITFs can only be achieved via intra-band electronic transitions. The strong absorption can be observed up to sub-terahertz frequencies. With increasing temperature, the absorption intensity increases significantly and the cut-off frequency is blue-shifted. More interestingly, we find that the absorption of the SAWs by the TITFs can be markedly enhanced by the tunable subgap in the Dirac energy spectrum of the TI surface states. Such a subgap is absent in conventional two-dimensional electron gases (2DEGs) and in the gapless Dirac 2DEG such as graphene. This study is pertinent to the exploration of the acoustic properties of TIs and to potential application of TIs as tunable SAW devices working at hypersonic frequencies.

  15. A plant canopy light absorption model with application to wheat

    NASA Technical Reports Server (NTRS)

    Chance, J. E.; Lemaster, E. W.

    1977-01-01

    From the light absorption model the absorption of light in the photosynthetically active region of the spectrum was calculated for a Penjamo wheat crop for several situations including: (1) the percent absorption of the incident radiation by a canopy having a four layer structure; (2) the percent absorption of light by the individual layers within a four layer canopy and by the underlying soil; (3) the percent absorption of light by each vegetative canopy layer for variable sun angle; and (4) the cumulative solar energy absorbed by the developing wheat canopy as it progresses from a single layer through its growth stages to a three layer canopy. This calculation was also presented as a function of the leaf area index.

  16. The anxiety disorder spectrum

    PubMed Central

    Lang, Peter J.; McTeague, Lisa M.

    2008-01-01

    This review considers recent research assessing psychophysiological reactivity to fear imagery in anxiety disorder patients. As in animal subjects, fear cues prompt in humans a state of defensive motivation in which autonomic and somatic survival reflexes are markedly enhanced. Thus, a startle stimulus presented in a fear context yields a stronger (potentiated) reflex, providing a quantitative measure of fearful arousal. This fear potentiation is further exaggerated in specific or social phobia individuals when viewing pictures or imagining the phobic object. Paradoxically, fear imagery studies with more severe anxiety disorder patients—panic disorder with agoraphobia, generalized anxiety disorder, or anxious patients with comorbid depression—show a blunted, less robust fear potentiated response. Furthermore, this reflex blunting appears to systematically be more pronounced over the anxiety disorder spectrum, coincident with lengthier chronicity, worsening clinician-based judgments of severity and prognosis, and increased questionnaire-based indices of negative affectivity, suggesting that normal defensive reactivity may be compromised by an experience of long-term stress. PMID:19096959

  17. Spectral Fingerprinting of Individual Cells Visualized by Cavity-Reflection-Enhanced Light-Absorption Microscopy

    PubMed Central

    Arai, Yoshiyuki; Yamamoto, Takayuki; Minamikawa, Takeo; Takamatsu, Tetsuro; Nagai, Takeharu

    2015-01-01

    The absorption spectrum of light is known to be a “molecular fingerprint” that enables analysis of the molecular type and its amount. It would be useful to measure the absorption spectrum in single cell in order to investigate the cellular status. However, cells are too thin for their absorption spectrum to be measured. In this study, we developed an optical-cavity-enhanced absorption spectroscopic microscopy method for two-dimensional absorption imaging. The light absorption is enhanced by an optical cavity system, which allows the detection of the absorption spectrum with samples having an optical path length as small as 10 μm, at a subcellular spatial resolution. Principal component analysis of various types of cultured mammalian cells indicates absorption-based cellular diversity. Interestingly, this diversity is observed among not only different species but also identical cell types. Furthermore, this microscopy technique allows us to observe frozen sections of tissue samples without any staining and is capable of label-free biopsy. Thus, our microscopy method opens the door for imaging the absorption spectra of biological samples and thereby detecting the individuality of cells. PMID:25950513

  18. Radiation detector spectrum simulator

    DOEpatents

    Wolf, Michael A.; Crowell, John M.

    1987-01-01

    A small battery operated nuclear spectrum simulator having a noise source nerates pulses with a Gaussian distribution of amplitudes. A switched dc bias circuit cooperating therewith generates several nominal amplitudes of such pulses and a spectral distribution of pulses that closely simulates the spectrum produced by a radiation source such as Americium 241.

  19. Radiation detector spectrum simulator

    DOEpatents

    Wolf, M.A.; Crowell, J.M.

    1985-04-09

    A small battery operated nuclear spectrum simulator having a noise source generates pulses with a Gaussian distribution of amplitudes. A switched dc bias circuit cooperating therewith to generate several nominal amplitudes of such pulses and a spectral distribution of pulses that closely simulates the spectrum produced by a radiation source such as Americium 241.

  20. The CMBR spectrum

    SciTech Connect

    Stebbins, A.

    1997-05-01

    Here we give an introduction to the observed spectrum of the Cosmic Microwave Background Radiation (CMBR) and discuss what can be learned about it. Particular attention will be given to how Compton scattering can distort the spectrum of the CMBR. An incomplete bibliography of relevant papers is also provided.

  1. Fission Spectrum Related Uncertainties

    SciTech Connect

    G. Aliberti; I. Kodeli; G. Palmiotti; M. Salvatores

    2007-10-01

    The paper presents a preliminary uncertainty analysis related to potential uncertainties on the fission spectrum data. Consistent results are shown for a reference fast reactor design configuration and for experimental thermal configurations. However the results obtained indicate the need for further analysis, in particular in terms of fission spectrum uncertainty data assessment.

  2. Fetal Alcohol Spectrum Disorder

    ERIC Educational Resources Information Center

    Caley, Linda M.; Kramer, Charlotte; Robinson, Luther K.

    2005-01-01

    Fetal alcohol spectrum disorder (FASD) is a serious and widespread problem in this country. Positioned within the community with links to children, families, and healthcare systems, school nurses are a critical element in the prevention and treatment of those affected by fetal alcohol spectrum disorder. Although most school nurses are familiar…

  3. OBSERVATIONS OF THE NEAR-INFRARED SPECTRUM OF THE ZODIACAL LIGHT WITH CIBER

    SciTech Connect

    Tsumura, K.; Matsumoto, T.; Matsuura, S.; Wada, T.; Battle, J.; Bock, J.; Zemcov, M.; Cooray, A.; Hristov, V.; Levenson, L. R.; Mason, P.; Sullivan, I.; Keating, B.; Renbarger, T.; Lee, D. H.; Nam, U. W.; Suzuki, K.

    2010-08-10

    Interplanetary dust (IPD) scatters solar radiation which results in the zodiacal light that dominates the celestial diffuse brightness at optical and near-infrared wavelengths. Both asteroid collisions and cometary ejections produce the IPD, but the relative contribution from these two sources is still unknown. The low resolution spectrometer (LRS) onboard the Cosmic Infrared Background ExpeRiment (CIBER) observed the astrophysical sky spectrum between 0.75 and 2.1 {mu}m over a wide range of ecliptic latitude. The resulting zodiacal light spectrum is redder than the solar spectrum, and shows a broad absorption feature, previously unreported, at approximately 0.9 {mu}m, suggesting the existence of silicates in the IPD material. The spectral shape of the zodiacal light is isotropic at all ecliptic latitudes within the measurement error. The zodiacal light spectrum, including the extended wavelength range to 2.5 {mu}m using Infrared Telescope in Space (IRTS) data, is qualitatively similar to the reflectance of S-type asteroids. This result can be explained by the proximity of S-type asteroidal dust to Earth's orbit, and the relatively high albedo of asteroidal dust compared with cometary dust.

  4. [Research on the NO2 mean concentration measurement with target differential optical absorption spectroscopy technology].

    PubMed

    Liu, Jin; Si, Fu-Qi; Zhou, Hai-Jin; Zhao, Min-Jie; Dou, Ke; Liu, Wen-Qing

    2013-04-01

    A new monitoring method of NO2 concentration near ground with the target difference absorption spectrum technology (Target DOAS) is introduced in the present paper. This method is based on the passive difference absorption spectrum technology. The instrument collects solar reflection spectrum of remote objectives, such as wall of building and mountain, and a specific reference spectrum is chosen to subtract the influence of trace gases from the target to atmospheric top, then integrated concentration of NO2 along the path between the target and instrument can be calculated through the differential absorption spectra inversion algorithm. Since the distance between the instrument and target is given, the mean concentration of NO2 can be derived. With developed Target DOAS instrument, NO2 concentration measurement was carried out in Hefei. And comparison was made between the target DOAS and long path difference absorption spectrometer. Good consistency was presented, proving the feasibility of this method. PMID:23841393

  5. Multiphoton absorption in amyloid protein fibres

    NASA Astrophysics Data System (ADS)

    Hanczyc, Piotr; Samoc, Marek; Norden, Bengt

    2013-12-01

    Fibrillization of peptides leads to the formation of amyloid fibres, which, when in large aggregates, are responsible for diseases such as Alzheimer's and Parkinson's. Here, we show that amyloids have strong nonlinear optical absorption, which is not present in native non-fibrillized protein. Z-scan and pump-probe experiments indicate that insulin and lysozyme β-amyloids, as well as α-synuclein fibres, exhibit either two-photon, three-photon or higher multiphoton absorption processes, depending on the wavelength of light. We propose that the enhanced multiphoton absorption is due to a cooperative mechanism involving through-space dipolar coupling between excited states of aromatic amino acids densely packed in the fibrous structures. This finding will provide the opportunity to develop nonlinear optical techniques to detect and study amyloid structures and also suggests that new protein-based materials with sizable multiphoton absorption could be designed for specific applications in nanotechnology, photonics and optoelectronics.

  6. Soil and Water: Some Teaching Suggestions.

    ERIC Educational Resources Information Center

    Fischer, Richard B.

    1987-01-01

    Outlines six soil and water investigations that students can pursue outdoors, in nature centers, or in classrooms: soil characteristics; relationship between soil ph and plant life; what aggregates tell us; differences in soil structure; differences in rate of water absorption by soil; and soil exploration with a Berlesi funnel. (NEC)

  7. Intergalactic Helium Absorption toward High-Redshift Quasars

    NASA Technical Reports Server (NTRS)

    Giroux, Mark L.; Fardal, Mark A.; Shull, J. Michael

    1995-01-01

    The recent Hubble Space Telescope (HST) observations of the z(q) = 3.286 quasar Q0302-003 (Jakobsen et at. 1994) and the z(q) = 3.185 quasar Q1935-67 by Tytler (1995) show absorption edges at the redshifted wavelength of He II 304 A. A key goal is to distinguish between contributions from discrete Ly-alpha forest clouds and a smoothly distributed intergalactic medium (IGM). We model the contributions from each of these sources of He II absorption, including the distribution of line Doppler widths and column densities, the 'He II proximity effect' from the quasar, and a self-consistent derivation of the He II opacity of the universe as a function of the spectrum of ionizing sources, with the assumption that both the clouds and the IGM are photoionized. The He II edge can be fully accounted for by He II line blanketing for reasonable distributions of line widths and column densities in the Ly-alpha forest, provided that the ionizing sources have spectral index alpha(s) greater than 1.5, and any He II proximity effect is neglected. Even with some contribution from a diffuse IGM, it is difficult to account for the edge observed by Jakobsen et al. (1994) with a 'hard' source spectrum (alpha(s) less than 1.3). The proximity effect modifies the relative contributions of the clouds and IGM to tau(He II) near the quasar (z approx. less than z(q)) and markedly increases the amount of He II absorption required. This implies, for example, that to account for the He II edge with line blanketing alone, the minimum spectral index alpha(s) must be increased from 1.5 to 1.9. We demonstrate the need for higher resolution observations that characterize the change in transmission as z approaches z(q) and resolve line-free gaps in the continuum. We set limits on the density of the diffuse IGM and suggest that the IGM and Ly-alpha clouds are likely to be a significant repository for dark baryons.

  8. Direction dependence of the magneto-optical absorption in nanowires with Rashba interaction

    NASA Astrophysics Data System (ADS)

    Sakr, M. R.

    2016-09-01

    We study the directional dependence of the absorption spectrum of ballistic nanowires in the presence of gate-controlled Rashba spin-orbit interaction and an in-plane magnetic field. In the weak Rashba regime, our analytical and numerical results show that the absorption peaks associated with the first and third intersubband transitions exhibit frequency shifts and strong amplitude modulations as the direction of the magnetic field changes. If the field is parallel to the nanowire axis, these peaks disappear and the resonance frequencies of the whole absorption spectrum are given merely in terms of the Zeeman splitting and the energy scale characterizing the confinement potential. The second transition has an absorption peak that suffers an opposite frequency shift with amplitude that is largely direction independent. The amplitude modulation and frequency shift of the absorption spectrum is periodic in the angle that the magnetic field makes with the nanowire axis.

  9. Petawatt laser absorption bounded

    NASA Astrophysics Data System (ADS)

    Levy, Matthew; Wilks, Scott; Tabak, Max; Libby, Stephen; Baring, Matthew

    2014-10-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top relativistic particle accelerators, ultrafast charged particle imaging systems and fast ignition inertial confinement fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. In this presentation, using a relativistic Rankine-Hugoniot-like analysis, we show how to derive the theoretical maximum and minimum of f. These boundaries constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. Close agreement is shown with several dozens of published experimental data points and simulation results, helping to confirm the theory. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials.

  10. An investigation of a mathematical model for atmospheric absorption spectra

    NASA Technical Reports Server (NTRS)

    Niple, E. R.

    1979-01-01

    A computer program that calculates absorption spectra for slant paths through the atmosphere is described. The program uses an efficient convolution technique (Romberg integration) to simulate instrument resolution effects. A brief information analysis is performed on a set of calculated spectra to illustrate how such techniques may be used to explore the quality of the information in a spectrum.

  11. Spectral effects on direct-insolation absorptance of five collector coatings

    NASA Technical Reports Server (NTRS)

    Hotchkiss, G. B.; Simon, F. F.; Burmeister, L. C.

    1979-01-01

    Absorptances for direct insolation of black chrome, black nickel, copper oxide, and two black zinc conversion selective coatings were calculated for a number of typical solar spectrums. Measured spectral reflectances were used while the effects of atmospheric ozone density, turbidity, and air mass were incorporated in calculated direct solar spectrums. Absorptance variation for direct insolation was found to be of the order of 1 percent for a typical range of clear-sky atmospheric conditions.

  12. The frequency spectrum of the Casimir effect

    SciTech Connect

    Lang, Andrew S.I.D.

    2005-10-01

    The frequency spectrum of the Casimir effect between parallel plates is studied. Calculations are performed for both the massless scalar field and the electromagnetic field cases, first using a spectral weight function, and then via the Fourier transform of the renormalized expectation of the Casimir energy-momentum operator. The Casimir force is calculated using the spectrum for two plates which are perfectly transparent in a frequency band. The result of this calculation suggests a way to detect the frequency spectrum of the Casimir effect.

  13. Spectrum of the microwave background radiation

    SciTech Connect

    Richards, P.L.

    1982-04-01

    A review is given of the present status of measurements of the spectrum of the microwave background. Factors which limit experimental accuracy are discussed with particular reference to high frequency measurements. A selection of the available measurements yields a data set which is reasonably consistent with the blackbody spectrum for a temperature of 2.9 K. A simple statistical analysis suggests either that there are errors in the data set, or that deviations from a blackbody spectrum exist. The difficulties inherent in property averaging the results from different observers are described. Prospects for improved measurements will be summarized.

  14. Spectrum of the microwave background radiation

    NASA Technical Reports Server (NTRS)

    Richards, P. L.

    1982-01-01

    A review is given of the present status of measurements of the spectrum of the microwave background. Factors that limit experimental accuracy are discussed with particular reference to high-frequency measurements. A selection of the available measurements yields a data set that is reasonably consistent with the black-body spectrum for a temperature of 2.9 K. A simple statistical analysis suggests either that there are errors in the data set, or that deviations from a black-body spectrum exist. The difficulties inherent in properly averaging the results from different observers are described. Prospects for improved measurements are summarized.

  15. Enhanced absorption in silicon metamaterials waveguide structure

    NASA Astrophysics Data System (ADS)

    Hamouche, Houria; Shabat, Mohammed M.

    2016-07-01

    Metamaterial waveguide structures for silicon solar cells are a novel approach to antireflection coating structures that can be used for the achievement of high absorption in silicon solar cells. This paper investigates numerically the possibility of improving the performance of a planar waveguide silicon solar cell by incorporating a pair of silicon nitride/metamaterial layer between a semi-infinite glass cover layer and a semi-infinite silicon substrate layer. The optimized layer thicknesses of the pair are determined under the solar spectrum AM1.5 by the effective average reflectance method. The transmission and reflection coefficients are derived by the transfer matrix method for values of metamaterial's refractive index in visible and near-infrared radiation. In addition, the absorption coefficient is examined for several angles of incidence of the transverse electric polarized (TE), transverse magnetic polarized (TM) and the total (TE&TM) guided waves. Numerical results provide an extremely high absorption. The absorptivity of the structure achieves greater than 98 %.

  16. Percutaneous absorption from soil.

    PubMed

    Andersen, Rosa Marie; Coman, Garrett; Blickenstaff, Nicholas R; Maibach, Howard I

    2014-01-01

    Abstract Some natural sites, as a result of contaminants emitted into the air and subsequently deposited in soil or accidental industrial release, have high levels of organic and non-organic chemicals in soil. In occupational and recreation settings, these could be potential sources of percutaneous exposure to humans. When investigating percutaneous absorption from soil - in vitro or vivo - soil load, particle size, layering, soil "age" time, along with the methods of performing the experiment and analyzing the results must be taken into consideration. Skin absorption from soil is generally reduced compared with uptake from water/acetone. However, the absorption of some compounds, e.g., pentachlorophenol, chlorodane and PCB 1254, are similar. Lipophilic compounds like dichlorodiphenyltrichloroethane, benzo[A]pyrene, and metals have the tendency to form reservoirs in skin. Thus, one should take caution in interpreting results directly from in vitro studies for risk assessment; in vivo validations are often required for the most relevant risk assessment. PMID:25205703

  17. Consecutive combined response spectrum

    NASA Astrophysics Data System (ADS)

    Xu, Longjun; Zhao, Guochen; Liu, Qingyang; Xie, Yujian; Xie, Lili

    2014-12-01

    Appropriate estimates of earthquake response spectrum are essential for design of new structures, or seismic safety evaluation of existing structures. This paper presents an alternative procedure to construct design spectrum from a combined normalized response spectrum (NRSC) which is obtained from pseudo-velocity spectrum with the ordinate scaled by different peak ground amplitudes (PGA, PGV, PGD) in different period regions. And a consecutive function f( T) used to normalize the ordinates is defined. Based on a comprehensive study of 220 strong ground motions recorded during recent eleven large worldwide earthquakes, the features of the NRSC are discussed and compared with the traditional normalized acceleration, velocity and displacement response spectra (NRSA, NRSV, NRSD). And the relationships between ground amplitudes are evaluated by using a weighted mean method instead of the arithmetic mean. Then the NRSC is used to define the design spectrum with given peak ground amplitudes. At last, the smooth spectrum is compared with those derived by the former approaches, and the accuracy of the proposed spectrum is tested through an analysis of the dispersion of ground motion response spectra.

  18. Axion isocurvature fluctuations with extremely blue spectrum

    SciTech Connect

    Kasuya, Shinta; Kawasaki, Masahiro

    2009-07-15

    We construct an axion model for generating isocurvature fluctuations with blue spectrum, n{sub iso}=2-4, which is suggested by recent analyses of admixture of adiabatic and isocurvature perturbations with independent spectral indices, n{sub ad}{ne}n{sub iso}. The distinctive feature of the model is that the spectrum is blue at large scales while scale invariant at small scales. This is naturally realized by the dynamics of the Peccei-Quinn scalar field.

  19. A High Signal-To-Noise Ultraviolet Spectrum of NGC 7469: New Support for Reprocessing of Continuum Radiation

    NASA Technical Reports Server (NTRS)

    Kriss, Gerard A.; Peterson, Bradley M.; Crenshaw, D. Michael; Zheng, Wei

    2000-01-01

    From 1996 June 10 to 1996 July 29, the International AGN Watch monitored the Seyfert 1 galaxy NGC 7469 using the International Ultraviolet Explorer, the Rossi X-Ray Timing Explorer, and a network of ground-based observatories. On 1996 June 18, in the midst of this intensive monitoring period, we obtained a high signal-to-noise snapshot of the UV spectrum from 1150 to 3300 A, using the Faint Object Spectrograph (FOS) on the Hubble Space Telescope. This spectrum allows us to disentangle the UV continuum more accurately from the broad wings of the emission lines, to identify clean continuum windows free of contaminating emission and absorption, and to deblend line complexes such as Ly(alpha) + N V, C IV + He II + O III], Si III] + C III], and Mg II + Fe II. Using the FOS spectrum as a template, we have fitted and extracted line and continuum fluxes from the IUE monitoring data. The cleaner continuum extractions c o n h the discovery of time delays between the different UV continuum bands by Wanders et al. Our new measurements show delays increasing with wavelength for continuum bands centered at 1485, 1740, and 1825 A, relative to 1315 A with delays of 0.09, 0.28, and 0.36 days, respectively. Like many other Seyfert I galaxies, the UV spectrum of NGC 7469 shows intrinsic, blue-shifted absorption in Ly(alpha), N V, and C IV. Soft X-ray absorption is also visible in archival ASCA X-ray spectra. The strength of the UV absorption, however, is not compatible with a single-zone model in which the same material absorbs both the UV and X-ray light. Similar to other Seyfert galaxies, such as NGC 3516, the UV-absorbing gas in NGC 7469 has a lower ionization parameter and column density than the X-ray-absorbing material. While the UV and X-ray absorption does not arise in the same material, the frequent occurrence of both associated UV absorption and X-ray warm absorbers in the same galaxies suggests that the gas supply for each has a common origin.

  20. Modeling the reflectance spectrum of Callisto 0.25 to 4.1μm

    USGS Publications Warehouse

    Calvin, Wendy M.; Clark, Roger N.

    1991-01-01

    The reflectance spectrum of Callisto from 0.2 to 4.1 μm is modeled using a simultaneous intimate plus areal mixture solution of ice and dark material which satisfies absorption band depths and reflectance levels. The model uses the radiative transfer theory based on Hapke's (1981, J. Geophys. Res. 86, 3039–3054) work, optical constants of materials and includes effects of grain size and abundance of each material. The best-fitting models contain 20–45 wt% ice in the optical surface. The models indicate that the ice component of the surface is fairly large gained and that the ice cannot account for major spectral features beyond approximately 2.5 μm. In this spectral region other hydrated minerals must dominate. A variety of reasonably well-fitting models were found and the amount of ice determined for these best fits was mathematically removed from the original Callisto spectrum. All of the spectra determined for the non-material were quite similar to each other and have absorption features that resemble hydrated silicates bearing both oxidation states of iron. Certain features in the Callisto non-ice spectrum can be duplicated by mixtures of Fe- and Mg-end member serpentines. Discrepancies indicate that other phases, possibly opaque minerals, are also required to match the entire spectrum. The unusual Fe-serpentines are commonly found in the matrices of primitive cabodnaceous chondrites, suggesting that other matrix phases may also be likely candidates for the Callisto non-ice material.

  1. Absorption heat pump system

    DOEpatents

    Grossman, Gershon; Perez-Blanco, Horacio

    1984-01-01

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  2. Shuttle spectrum despreader

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The results of the spread spectrum despreader project are reported and three principal products are designed and tested. The products are, (1) a spread spectrum despreader breadboard, (2) associated test equipment consisting of a spectrum spreader and bit reconstruction/error counter and (3) paper design of a Ku-band receiver which would incorporate the despreader as a principal subsystem. The despreader and test set are designed for maximum flexibility. A choice of unbalanced quadriphase or biphase shift keyed data modulation is available. Selectable integration time and threshold voltages on the despreader further lend true usefulness as laboratory test equipment to the delivered hardware.

  3. Soft X-ray Absorption Edges in LMXBs

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The XMM observation of LMC X-2 is part of our program to study X-ray absorption in the interstellar medium (ISM). This program includes a variety of bright X-ray binaries in the Galaxy as well as the Magellanic Clouds (LMC and SMC). LMC X-2 is located near the heart of the LMC. Its very soft X-ray spectrum is used to determine abundance and ionization fractions of neutral and lowly ionized oxygen of the ISM in the LMC. The RGS spectrum so far allowed us to determine the O-edge value to be for atomic O, the EW of O-I in the ls-2p resonance absorption line, and the same for O-II. The current study is still ongoing in conjunction with other low absorption sources like Sco X-1 and the recently observed X-ray binary 4U 1957+11.

  4. Absorption in X-ray spectra of high-redshift quasars

    NASA Technical Reports Server (NTRS)

    Elvis, Martin; Fiore, Fabrizio; Wilkes, Belinda; Mcdowell, Jonathan; Bechtold, Jill

    1994-01-01

    We present evidence that X-ray absorption is common in high-redshift quasars. We have studied six high-redshift (z approximately 3) quasars with the ROSAT Position Sensitive Proportional Counter (PSPC) of which four are in directions of low Galactic N(sub H). Three out of these four show excess absorption, while only three in approximately 50 z approximately less than 0.4 quasars do, indicating that such absorption must be common, but not ubiquitous, at high redshifts, and that the absorbers must lie at z greater than 0.4. The six quasars were: S5 0014+81, Q0420-388, PKS 0438-436, S4 0636+680. PKS 2000-330, PKS 2126-158, which have redshifts between 2.85 and 3.78. PKS 0438-436 and PKS 2126-158 show evidence for absorption above the local Galactic value at better than 99.999% confidence level. If the absorber is at the redshift of the quasar, then values of N(sub H) = (0.86(+0.49, -0.28)) x 10(exp 22) atoms/sq cm for PKS 0438-436, and N(sub H) = (1.45(+1.20, -0.64)) x 10(exp 22) atoms/ sq cm for PKS 2126-158, are implied, assuming solar abundances. The spectrum of S4 0636+680 also suggests the presence of a similarly large absorption column density at the 98% confidence level. This absorption reverses the trend for the most luminous active galactic nuclei (AGN) to have the least X-ray absorption, so a new mechanism is likely to be responsible. Intervening absorption due to damped Lyman(alpha) systems is a plausible cause. We also suggest, as an intrinsic model, that intracluster material, e.g., a cooling flow, around the quasar could account for both the X-ray spectrum and other properties of these quasars. All the quasars are radio-loud and three are gigahertz peaked (two of the three showing absorption). No excess absorption above the Galactic value is seen toward Q0420-388. This quasar has two damped Lyman(alpha) systems at z = 3.08. The limit on the X-ray column density implies a low ionization fraction, N(H I)/N(H) approximately greater than 4 x 10(exp -3) (3

  5. An iron absorption model of gamma-ray burst spectra

    NASA Technical Reports Server (NTRS)

    Liang, Edison P.; Kargatis, Vincent E.

    1994-01-01

    Most gamma-ray bursts (GRBs) exhibit deficits of X-rays below approximately 200 keV. Here we consider a spectral model in which the burst source is shielded by an optically thick layer of circumburster material (CBM) rich in iron-group elements whose photoelectric absorption opacity exceeds the Thomson opacity below approximately 120 keV. For power-law distributions of absorption depths along the lines of sight the absorbed spectrum can indeed mimic the typial GRB spectrum. This model predicts that (a) the spectrum should evolve monotonically from hard to soft during each energy release, which is observed in most bursts, especially in fast rise exponential decay bursts; (b) Fe spectral features near 7 keV may be present in some bursts; and (c) the ratio of burst distances to the CBM and to Earth should be approximately 10(exp -11) if the spectral evolution is purely due to Fe stripping by the photons.

  6. The lunar neutron energy spectrum inferred from the isotope compositions of rare-earth elements and hafnium in Apollo samples

    NASA Astrophysics Data System (ADS)

    Albalat, Emmanuelle; Blichert-Toft, Janne; Telouk, Philippe; Albarède, Francis

    2015-11-01

    The isotopic abundances of Sm, Gd, Dy, Er, Yb, and Hf have been measured in nine lunar samples by MC-ICP-MS. The data were corrected for both instrumental mass bias and natural isotope fractionation. We used the data to calculate the total flux and energy spectrum of the neutrons absorbed by the rocks. We write the constitutive equations of the isotopic changes for these elements induced by neutrons and solve the inverse problem by computing local energy averages. Resonant absorption peaks can be used as convenient kernels to define the spectrum of epithermal neutrons. We find that 149Sm and 157Gd anomalies correlate with neutron flux density for E < 0.015 eV (r2 > 0.98) and E ≈ 0.13 eV (r2 > 0.85), while no significant correlation exists between the ratio of these anomalies and the epithermal/thermal flux ratio at any value of energy. Neutron flux density variations can be used to trace the proportions of neutrons scattered out of the samples. The spectrum in the thermal region follows the expected E - 1 / 2 dependence but with 'notches' corresponding to neutron absorption. A major notch at the lowest end of the epithermal neutron spectrum (0.2-0.8 eV) is possibly due to absorption of neutrons by 151Eu, 167Er, and 149Sm. In general, we find a rather good correlation between the neutron flux density at specific energies and the exposure age, which suggests a mean residence time of the samples at the surface of the regolith of 2-300 Ma. Another correlation of epithermal neutrons with sample wt% FeO + TiO2 is consistent with orbital reflectance observations.

  7. Jupiter's atmospheric composition and cloud structure deduced from absorption bands in reflected sunlight

    NASA Technical Reports Server (NTRS)

    Sato, M.; Hansen, J. E.

    1979-01-01

    The spectrum of sunlight reflected by Jupiter is analyzed by comparing observations of Woodman (1979) with multiple-scattering computations. The analysis yields information on the vertical cloud structure at several latitudes and on the abundance of CH4 and NH3 in the atmosphere of Jupiter. The abundances of CH4 and NH3 suggest that all ices and rocks are overabundant on Jupiter by a factor of 2 or more, providing an important constraint on models for the formation of Jupiter from the primitive solar nebula. The pressure level of the clouds, the gaseous NH3 abundance, the mean temperature profile, and the Clausius-Clapeyron relation suggest that these clouds are predominantly ammonia crystals with the cloud bottom at 600-700 mb. A diffuse distribution of aerosols exists between 150 and 500 mb, and the spectral variation of albedo reflects a changing bulk absorption coefficient of the material composing the aerosols and is diagnostic of the aerosol composition.

  8. Iron, lead, and cobalt absorption: similarities and dissimilarities

    SciTech Connect

    Barton, J.C.; Conrad, M.E.; Holland, R.

    1981-01-01

    Using isolated intestinal segments in rats, the absorption of iron, lead, and cobalt was increased in iron deficiency and decreased in iron loading. Similarly, the absorption of these metals was decreased in transfusional erythocytosis, after intravenous iron injection and after parenteral endotoxin injection. Acute bleeding or abbreviated intervals of dietary iron deprivation resulted in increased iron absorption from isolated intestinal segments and in intact animals, while the absorption of lead and cobalt was unaffected. These results suggest that the specificity of the mucosal metal absorptive mechanism is either selectively enhanced for iron absorption by phlebotomy or brief periods of dietary iron deprivation, or that two or more mucosal pathways for iron absorption may exist.

  9. IRIS Spectrum Line Plot

    NASA Video Gallery

    This video shows a line plot of the spectrum. The spectra here are shown for various locations on the Sun. The changes in the movie are caused by differing physical conditions in the locations. Cre...

  10. Fetal Alcohol Spectrum Disorders

    MedlinePlus

    ... alcohol can cause a group of conditions called fetal alcohol spectrum disorders (FASDs). Effects can include physical and behavioral problems such ... alcohol syndrome is the most serious type of FASD. People with fetal alcohol syndrome have facial abnormalities, ...

  11. Quantum Spread Spectrum Communication

    SciTech Connect

    Humble, Travis S

    2010-01-01

    We demonstrate that spectral teleportation can coherently dilate the spectral probability amplitude of a single photon. In preserving the encoded quantum information, this variant of teleportation subsequently enables a form of quantum spread spectrum communication.

  12. Two-Phonon Absorption

    ERIC Educational Resources Information Center

    Hamilton, M. W.

    2007-01-01

    A nonlinear aspect of the acousto-optic interaction that is analogous to multi-photon absorption is discussed. An experiment is described in which the second-order acousto-optically scattered intensity is measured and found to scale with the square of the acoustic intensity. This experiment using a commercially available acousto-optic modulator is…

  13. Total absorption Cherenkov spectrometers

    NASA Astrophysics Data System (ADS)

    Malinovski, E. I.

    2015-05-01

    A short review of 50 years of work done with Cherenkov detectors in laboratories at the Lebedev Physical Institute is presented. The report considers some issues concerning the use of Cherenkov total absorption counters based on lead glass and heavy crystals in accelerator experiments.

  14. Cholesterol Absorption and Metabolism.

    PubMed

    Howles, Philip N

    2016-01-01

    Inhibitors of cholesterol absorption have been sought for decades as a means to treat and prevent cardiovascular diseases (CVDs) associated with hypercholesterolemia. Ezetimibe is the one clear success story in this regard, and other compounds with similar efficacy continue to be sought. In the last decade, the laboratory mouse, with all its genetic power, has become the premier experimental model for discovering the mechanisms underlying cholesterol absorption and has become a critical tool for preclinical testing of potential pharmaceutical entities. This chapter briefly reviews the history of cholesterol absorption research and the various gene candidates that have come under consideration as drug targets. The most common and versatile method of measuring cholesterol absorption is described in detail along with important considerations when interpreting results, and an alternative method is also presented. In recent years, reverse cholesterol transport (RCT) has become an area of intense new interest for drug discovery since this process is now considered another key to reducing CVD risk. The ultimate measure of RCT is sterol excretion and a detailed description is given for measuring neutral and acidic fecal sterols and interpreting the results. PMID:27150091

  15. Lipids: Absorption and transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to the hydrophobic nature of lipids, dietary fat is handled differently than protein or carbohydrate with respect with digestion and absorption. Dietary fats are broken down throughout the gastrointestinal system. A unique group of enzymes and cofactors allows this process to proceed in an eff...

  16. ZINC ABSORPTION BY INFANTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zinc is a vital mineral in human nutrition, and rare cases of overt zinc deficiency are well described in term and preterm infants. A variety of methods have been developed to assess zinc absorption, retention, and balance in humans, either using mass (metabolic) balance or stable isotope-based METH...

  17. Absorption driven focus shift

    NASA Astrophysics Data System (ADS)

    Harrop, N.; Wolf, S.; Maerten, O.; Dudek, K.; Ballach, S.; Kramer, R.

    2016-03-01

    Modern high brilliance near infrared lasers have seen a tremendous growth in applications throughout the world. Increased productivity has been achieved by higher laser power and increased brilliance of lasers. Positive impacts on the performance and costs of parts are opposed to threats on process stability and quality, namely shift of focus position over time. A high initial process quality will be reduced by contamination of optics, eventually leading to a focus shift or even destruction of the optics. Focus analysis at full power of multi-kilowatt high brilliance lasers is a very demanding task because of high power densities in the spot and the high power load on optical elements. With the newly developed high power projection optics, the High-Power Micro-Spot Monitor High Brilliance (HP-MSM-HB) is able to measure focus diameter as low as 20 μm at power levels up to 10 kW at very low internal focus shift. A main driving factor behind thermally induced focus shift is the absorption level of the optical element. A newly developed measuring system is designed to determine the relative absorption level in reference to a gold standard. Test results presented show a direct correlation between absorption levels and focus shift. The ability to determine the absorption level of optical elements as well as their performance at full processing power before they are put to use, enables a high level of quality assurance for optics manufacturers and processing head manufacturers alike.

  18. Absorption and Fluorescence Properties of Chromophoric Dissolved Organic Matter Produced by Algae.

    PubMed

    Peng, Tong; Lu, Xiao-lan; Su, Rong-guo; Zhang, Dong-mei

    2015-09-01

    also increased clearly with the growth of marine microalgae, but protein-like fluorescent component had only a slow growth. Furthermore, the absorption spectrum of CDOM produced by different species of algae changed obviously and the relative composition fluorescence intensity of CDOM produced by different microalgae were found to vary among different composition from EEM, which suggested CDOM produced by different microalgae make quite different contributions to CDOM in natural seawater. PMID:26669142

  19. Absorption-polarization characteristics of rhodamine 6G and its base in poly(methyl methacrylate)

    SciTech Connect

    Prishchepov, A.S.; Nizamou, N.

    1986-01-01

    Results are presented of the measurement and analysis of the absorption-polarization characteristics of rhodamine 6G and the base of rhodamine 6G (BR6G) in polymeric films of poly(methylmethacrylate) (PMMA). The absorption spectrum of a PMMA film containing BR6G and the cationic dye in the monomeric and associated states are shown.

  20. UV absorption of the in-bore plasma emission from an EML using polycarbonate insulators

    NASA Astrophysics Data System (ADS)

    Clothiaux, Eugene J.

    1991-01-01

    The in-bore continuum emission spectrum, laced by absorption lines, is observed to be completely cut off for wavelengths shorter than about 3000 A. This cutoff wavelength is seen to occur at longer wavelengths as the plasma armature moves down the launcher bore. A mechanism for the absorption of shortwave radiation by ablated and evaporated bore materials is given.

  1. Venus - The 17- to 38-micron spectrum. [atmospheric thermal emission spectrum

    NASA Technical Reports Server (NTRS)

    Reed, R. A.; Forrest, W. J.; Houck, J. R.; Pollack, J. B.

    1978-01-01

    A far-IR emission spectrum of Venus covering the wavelength range from 17 to 38 microns is examined which was obtained on five nights at an altitude of 14 km with the 30-cm telescope of the NASA Lear Jet. The spectrum is found to be characterized by an overall continuum level with noticeable absorption shortward of 20 microns and longward of 30 microns as compared with a 245-K blackbody. The continuum level is taken as implying a continuous source of opacity in the Venusian atmosphere over the entire range from 17 to 38 microns with increased opacity shortward of 20 microns and longward of 30 microns. It is shown that a haze of sulfuric acid droplets can provide the necessary opacity and explain the observed depressions. A pressure level of roughly 200 mb is deduced for this spectrum.

  2. [Study of retrieving formaldehyde with differential optical absorption spectroscopy].

    PubMed

    Li, Yu-Jin; Xie, Pin-Hua; Qin, Min; Qu, Xiao-Ying; Hu, Lin

    2009-01-01

    The present paper introduces the method of retrieving the concentration of HCHO with differential optical absorption spectroscopy (DOAS). The authors measured ambient HCHO in Beijing region with the help of differential optical absorption spectroscopy instrument made by ourself, and discussed numerous factors in retrieving the concentration of HCHO with differential optical absorption spectroscopy (DOAS), especially, the choice of HCHO wave band, how to avoid absorption of ambient SO2, NO2 and O3, and the influence of the Xenon lamp spectrum structure on the absorption of ambient HCHO. The authors achieved the HCHO concentration by simultaneously retrieving the concentrations of HCHO, SO2, NO2 and O3 with non-linear least square fitting method, avoiding the effect of choosing narrow wave of HCHO and the residual of SO2, NO2, O3 and the Xenon lamp spectrum structure in retrieving process to attain the concentration of HCHO, Finally the authors analyzed the origin of error in retrieving the concentration of HCHO with differential optical absorption spectroscopy (DOAS), and the total error is within 13.7% in this method. PMID:19385238

  3. Iron K Features in the Quasar E 1821+643: Evidence for Gravitationally Redshifted Absorption?

    NASA Technical Reports Server (NTRS)

    Yaqoob, Tahir; Serlemitsos, Peter

    2005-01-01

    We report a Chandra high-energy grating detection of a narrow, redshifted absorption line superimposed on the red wing of a broad Fe K line in the z = 0.297 quasar E 1821+643. The absorption line is detected at a confidence level, estimated by two different methods, in the range approx. 2 - 3 sigma. Although the detection significance is not high enough to exclude a non-astrophysical origin, accounting for the absorption feature when modeling the X-ray spectrum implies that the Fe-K emission line is broad, and consistent with an origin in a relativistic accretion disk. Ignoring the apparent absorption feature leads to the conclusion that the Fe-K emission line is narrower, and also affects the inferred peak energy of the line (and hence the inferred ionization state of Fe). If the absorption line (at approx. 6.2 keV in the quasar frame) is real, we argue that it could be due to gravitationally redshifted Fe XXV or Fe XXVI resonance absorption within approx. 10 - 20 gravitational radii of the putative central black hole. The absorption line is not detected in earlier ASCA and Chandra low-energy grating observations, but the absorption line is not unequivocally ruled out by these data. The Chandra high-energy grating Fe-K emission line is consistent with an origin predominantly in Fe I-XVII or so. In an ASCA observation eight years earlier, the Fe-K line peaked at approx. 6.6 keV, closer to the energies of He-like Fe triplet lines. Further, in a Chandra low-energy grating observation the Fe-K line profile was double-peaked, one peak corresponding to Fe I-XVII or so, the other peak to Fe XXVI Ly alpha. Such a wide range in ionization state of Fe is not ruled out by the HEG and ASCA data either, and is suggestive of a complex structure for the line-emitter.

  4. Single-particle absorption spectroscopy by photothermal contrast.

    PubMed

    Yorulmaz, Mustafa; Nizzero, Sara; Hoggard, Anneli; Wang, Lin-Yung; Cai, Yi-Yu; Su, Man-Nung; Chang, Wei-Shun; Link, Stephan

    2015-05-13

    Removing effects of sample heterogeneity through single-molecule and single-particle techniques has advanced many fields. While background free luminescence and scattering spectroscopy is widely used, recording the absorption spectrum only is rather difficult. Here we present an approach capable of recording pure absorption spectra of individual nanostructures. We demonstrate the implementation of single-particle absorption spectroscopy on strongly scattering plasmonic nanoparticles by combining photothermal microscopy with a supercontinuum laser and an innovative calibration procedure that accounts for chromatic aberrations and wavelength-dependent excitation powers. Comparison of the absorption spectra to the scattering spectra of the same individual gold nanoparticles reveals the blueshift of the absorption spectra, as predicted by Mie theory but previously not detectable in extinction measurements that measure the sum of absorption and scattering. By covering a wavelength range of 300 nm, we are furthermore able to record absorption spectra of single gold nanorods with different aspect ratios. We find that the spectral shift between absorption and scattering for the longitudinal plasmon resonance decreases as a function of nanorod aspect ratio, which is in agreement with simulations. PMID:25849105

  5. 29 CFR 785.45 - Suggestion systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Suggestion systems. 785.45 Section 785.45 Labor Regulations..., Medical Attention, Civic and Charitable Work, and Suggestion Systems § 785.45 Suggestion systems... general suggestion system is not working time, but if employees are permitted to work on...

  6. The Electronic Spectrum of the Fulvenallenyl Radical.

    PubMed

    Chakraborty, Arghya; Fulara, Jan; Maier, John P

    2016-01-01

    The fulvenallenyl radical was produced in 6 K neon matrices after mass-selective deposition of C7H5(-) and C7H5(+) generated from organic precursors in a hot cathode ion source. Absorption bands commencing at λ=401.3 nm were detected as a result of photodetachment of electrons from the deposited C7H5(-) and also by neutralization of C7H5(+) in the matrix. The absorption system is assigned to the 1 (2)B1 ←X (2)B1 transition of the fulvenallenyl radical on the basis of electronic excitation energies calculated with the MS-CASPT2 method. The vibrational excitation bands detected in the spectrum concur with the structure of the fulvenallenyl radical. Employing DFT calculations, it is found that the fulvenallenyl anion and its radical are the global minima on the potential energy surface among plausible structures of C7H5. PMID:26593635

  7. Optical spectrum variations of IL Cep A

    NASA Astrophysics Data System (ADS)

    Ismailov, N. Z.; Khalilov, O. V.; Bakhaddinova, G. R.

    2016-02-01

    The results of many-year uniform spectroscopic observations of the Herbig Ae/Be star IL Cep A are presented. Its Hα line has either a single or a barely resolved two-component emission profile. The H β emission line is clearly divided into two components with a deep central absorption. Smooth variations of the observed parameters of individual spectral lines over nine years are observed. The He I λ5876 Å line has a complex absorption profile, probably with superposed emission components. The NaI D1, D2 doublet exhibits weak changes due to variations in the circumstellar envelope. The variations observed in the stellar spectrum can be explained by either binarity or variations of the magnetic field in the stellar disk. Difficulties associated with both these possibilities are discussed.

  8. The shell spectrum of HD 94509

    NASA Astrophysics Data System (ADS)

    Cowley, Charles R.; Przybilla, Norbert; Hubrig, Swetlana

    2015-01-01

    HD 94509 is a 9th magnitude Be star with an unusually rich metallic-lined shell. The absorption spectrum is rich, comparable to that of an A or F supergiant, but Mg II (4481A), and the Si II (4128 and 4130A), are weak, indicating a dilute radiation field, as described by Otto Struve. The H-alpha emission is double with components of equal intensity and an absorption core that dips well below the stellar continuum. H-beta is weaker, but with a similar structure. H-gamma through H-epsilon have virtually black cores, indicating that the shell covers the stellar disk. The stronger metallic absorption lines are wide near the continuum, but taper to very narrow cores. This line shape is unexplained. However, the total absorption can be modeled to reveal an overall particle densities of 10^{10}-10^{12} cm^{-3}. An electron density log(n_e) = 11.2 is obtained from the Paschen-line convergence and the Inglis-Tellar relation. Column densities are obtained with the help of curves of growth by assuming uniform conditions in the cloud. These indicate a nearly solar composition. The CLOUDY code (Ferland, et al. Rev. Mex. Astron. Astroph. 49, 137, 213) is used to produce a model that predicts matching column densities of the dominant ions, the n = 3 level of hydrogen, the H-alpha strength, and the electron density (± 0.5 dex).

  9. An optical spectrum of the afterglow of a gamma-ray burst at a redshift of z = 6.295.

    PubMed

    Kawai, N; Kosugi, G; Aoki, K; Yamada, T; Totani, T; Ohta, K; Iye, M; Hattori, T; Aoki, W; Furusawa, H; Hurley, K; Kawabata, K S; Kobayashi, N; Komiyama, Y; Mizumoto, Y; Nomoto, K; Noumaru, J; Ogasawara, R; Sato, R; Sekiguchi, K; Shirasaki, Y; Suzuki, M; Takata, T; Tamagawa, T; Terada, H; Watanabe, J; Yatsu, Y; Yoshida, A

    2006-03-01

    The prompt gamma-ray emission from gamma-ray bursts (GRBs) should be detectable out to distances of z > 10 (ref. 1), and should therefore provide an excellent probe of the evolution of cosmic star formation, reionization of the intergalactic medium, and the metal enrichment history of the Universe. Hitherto, the highest measured redshift for a GRB has been z = 4.50 (ref. 5). Here we report the optical spectrum of the afterglow of GRB 050904 obtained 3.4 days after the burst; the spectrum shows a clear continuum at the long-wavelength end of the spectrum with a sharp cut-off at around 9,000 A due to Lyman alpha absorption at z approximately 6.3 (with a damping wing). A system of absorption lines of heavy elements at z = 6.295 +/- 0.002 was also detected, yielding the precise measurement of the redshift. The Si ii fine-structure lines suggest a dense, metal-enriched environment around the progenitor of the GRB. PMID:16525466

  10. Detection of the 2165 Inverse Centimeter (4.619 Micron) XCN Band in the Spectrum of L1551 IRS 5

    NASA Technical Reports Server (NTRS)

    Tegler, Stephen C.; Weintraub, David A.; Allamandola, Louis J.; Sandford, Scott A.; Rettig, Terrence W.; Campins, Humberto

    1993-01-01

    We report the detection of a broad absorption band at 2165 cm (4.619 microns) in the spectrum of L1551 IRS 5. New laboratory results over the 2200-2100 /cm wavenumber interval (4.55-4.76 microns), performed with realistic interstellar ice analogs, suggest that this feature is due to a CN-containing compound. We will refer to this compound as XCN. We also confirm the presence of frozen CO (both in nonpolar and polar matrices) through absorption bands at 2140 /cm (4.67 microns) and 2135 /cm (4.68 microns). The relative abundance of solid-state CO to frozen H2O is approx. 0.13 while the abundance of XCN seems comparable to that of frozen CO.

  11. Imprints of a high velocity wind on the soft x-ray spectrum of PG1211+143

    NASA Astrophysics Data System (ADS)

    Pounds, K. A.; Lobban, A.; Reeves, J. N.; Vaughan, S.; Costa, M.

    2016-04-01

    An extended XMM-Newton observation of the luminous narrow line Seyfert galaxy PG1211+143 in 2014 has revealed a more complex high velocity wind, with components distinguished in velocity, ionization level, and column density. Here we report soft x-ray emission and absorption features from the ionized outflow, finding counterparts of both high velocity components, v˜0.129c and v˜0.066c, recently identified in the highly ionized Fe K absorption spectrum. The lower ionization of the co-moving soft x-ray absorbers imply a distribution of higher density clouds embedded in the main outflow, while much higher column densities for the same flow component in the hard x-ray spectra suggest differing sight lines to the continuum x-ray source.

  12. Imprints of a high-velocity wind on the soft X-ray spectrum of PG1211+143

    NASA Astrophysics Data System (ADS)

    Pounds, K. A.; Lobban, A.; Reeves, J. N.; Vaughan, S.; Costa, M.

    2016-07-01

    An extended XMM-Newton observation of the luminous narrow-line Seyfert galaxy PG1211+143 in 2014 has revealed a more complex high-velocity wind, with components distinguished in velocity, ionization level, and column density. Here we report soft X-ray emission and absorption features from the ionized outflow, finding counterparts of both high-velocity components, v ˜ 0.129c and v ˜ 0.066c, recently identified in the highly ionized Fe K absorption spectrum. The lower ionization of the comoving soft X-ray absorbers imply a distribution of higher density clouds embedded in the main outflow, while much higher column densities for the same flow component in the hard X-ray spectra suggest differing sightlines to the continuum X-ray source.

  13. Mercury: surface composition from the reflection spectrum.

    PubMed

    McCord, T B; Adams, J B

    1972-11-17

    The reflection spectrum for the integral disk of the planet Mercury was measured and was found to have a constant positive slope from 0.32 to 1.05 micrometers, except for absorption features in the infrared. The reflectivity curve matches closely the curve for the lunar upland and mare regions. Thus, the surface of Mercury is probably covered with a lunar-like soil rich in dark glasses of high iron and titanium content. Pyroxene is probably the dominant mafic mineral. PMID:17798540

  14. The Ultraviolet Spectrum of the Jovian Dayglow

    NASA Technical Reports Server (NTRS)

    Liu, Weihong; Dalgarno, A.

    1995-01-01

    The ultraviolet spectra of molecular hydrogen H2 and HD due to solar fluorescence and photoelectron excitation are calculated and compared with the Jovian equatorial dayglow spectrum measured at 3 A resolution at solar maximum. The dayglow emission is accounted for in both brightness and spectral shape by the solar fluorescence and photoelectron excitation and requires no additional energy source. The emission is characterized by an atmospheric temperature of 530 K and an H2 column density of 10(exp 20) cm(exp -2). The dayglow spectrum contains a cascade contribution to the Lyman band emission from high-lying E and F states. Its relative weakness at short wavelengths is due to both self-absorption by H2 and absorption by CH4. Strong wavelength coincidences of solar emission lines and absorption lines of H2 and HD produce unique line spectra which can be identified in the dayglow spectrum. The strongest fluorescence is due to absorption of the solar Lyman-beta line at 1025.72 A by the P(1) line of the (6, 0) Lyman band of H2 at 1025.93 A. The fluorescence lines due to absorption of the solar O 6 line at 1031.91 A by vibrationally excited H2 via the Q(3) line of the (1, 1) Werner band at 1031.86 A are identified. The fluorescence lines provide a sensitive measure of the atmospheric temperature. There occurs an exact coincidence of the solar O 6 line at 1031.91 A and the R(0) line of the (6, 0) Lyman band of HD at 1031-91 A, but HD on Jupiter is difficult to detect due to the dominance of the H2 emission where the HD emission is particularly strong. Higher spectral resolution and higher sensitivity may make possible such a detection. The high resolution (0.3 A) spectra of H2 and HD are presented to stimulate search for the HD on Jupiter with the Hubble Space Telescope.

  15. 69. INTERIOR VIEW OF THE ABSORPTION TOWER BUILDING, ABSORPTION TOWER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    69. INTERIOR VIEW OF THE ABSORPTION TOWER BUILDING, ABSORPTION TOWER UNDER CONSTRUCTION. (DATE UNKNOWN). - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  16. Collision--induced absorption in dense atmospheres of cool stars

    SciTech Connect

    Borysow, Aleksandra; Joergensen, Uffe Graae

    1999-04-01

    In the atmosphere of the Sun the major interaction between the matter and the radiation is through light absorption by ions (predominantly the negative ion of hydrogen atoms), neutral atoms and a small amount of polar molecules. The majority of stars in the universe are, however, cooler and denser than our Sun, and for a large fraction of these, the above absorption processes are very weak. Here, collision-induced absorption (CIA) becomes the dominant opacity source. The radiation is absorbed during very short mutual passages ('collisions') of two non-polar molecules (and/or atoms), while their electric charge distributions are temporarily distorted which gives rise to a transient dipole moment. We present here a review of the present-day knowledge about the impact of collision-induced absorption processes on the structure and the spectrum of such stars.

  17. Absorption and emission by atmospheric gases - The physical processes

    NASA Astrophysics Data System (ADS)

    McCartney, E. J.

    This book has been written for those who wish to understand better the processes of absorption and emission and their manifold effects. Persons having such interests or needs are the workers in meteorology, atmospheric physics, aerospace surveillance, and air-pollution control. Introductory ideas and useful facts are presented, taking into account an overview of absorption and emission, the electromagnetic spectrum and its parameters, the quantization of energy, the molecular origins of spectra, and the laws of blackbody radiation. Gas properties are considered along with thermodynamics, molecular kinetics, quantized energy states and population, molecular internal energies, spectra of energy transitions, and parameters of line and band absorption. Attention is given to molecular dipole moments, rotational energy and transitions, vibrational energy and transitions, and absorption and emission data.

  18. Absorption of ac fields in amorphous indium-oxide films

    NASA Astrophysics Data System (ADS)

    Ovadyahu, Z.

    2014-08-01

    Absorption data from applied ac fields in Anderson-localized amorphous indium-oxide (InxO) films are shown to be frequency and disorder dependent. The absorption shows a roll-off at a frequency which is much lower than the electron-electron scattering rate of the material when it is in the diffusive regime. This is interpreted as evidence for discreteness of the energy spectrum of the deeply localized regime. This is consistent with recent many-body localization scenarios. As the metal-insulator transition is approached, the absorption shifts to higher frequencies. Comparing with the previously obtained results on the crystalline version of indium-oxide (In2O3-x) implies a considerably higher inelastic electron-phonon scattering rate in the amorphous material. The range over which the absorption versus frequency decreases may indicate that a wide distribution of localization length is a common feature in these systems.

  19. Micro acoustic spectrum analyzer

    DOEpatents

    Schubert, W. Kent; Butler, Michael A.; Adkins, Douglas R.; Anderson, Larry F.

    2004-11-23

    A micro acoustic spectrum analyzer for determining the frequency components of a fluctuating sound signal comprises a microphone to pick up the fluctuating sound signal and produce an alternating current electrical signal; at least one microfabricated resonator, each resonator having a different resonant frequency, that vibrate in response to the alternating current electrical signal; and at least one detector to detect the vibration of the microfabricated resonators. The micro acoustic spectrum analyzer can further comprise a mixer to mix a reference signal with the alternating current electrical signal from the microphone to shift the frequency spectrum to a frequency range that is a better matched to the resonant frequencies of the microfabricated resonators. The micro acoustic spectrum analyzer can be designed specifically for portability, size, cost, accuracy, speed, power requirements, and use in a harsh environment. The micro acoustic spectrum analyzer is particularly suited for applications where size, accessibility, and power requirements are limited, such as the monitoring of industrial equipment and processes, detection of security intrusions, or evaluation of military threats.

  20. Action spectrum for photocarcinogenesis.

    PubMed

    de Gruijl, F R

    1995-01-01

    The wavelength dependence of the carcinogenicity of ultraviolet (UV) radiation needs to be known in order to assess the carcinogenic risks of various UV sources, most notably the different solar UV spectra at ground level under depleting stratospheric ozone. This wavelength dependence cannot be extracted from human data (e.g., from epidemiology); it can, however, be directly obtained from animal experiments. Precise information on the wavelength dependence, the so-called action spectrum, was not available until recently: erythemal or mutagenic action spectra have been used as substitutes. However, experimental data on skin tumors induced in hairless mice (Skh:HR1) with various polychromatic sources have been building up. Our group has found that none of the substitute action spectra yield a statistically acceptable description of our data, and we have, therefore, derived a new action spectrum, dubbed the SCUP action spectrum (SCUP stands for Skin Cancer Utrecht-Philadelphia, because the action spectrum also fits experimental data from the former Skin and Cancer Hospital in Philadelphia). The SCUP action spectrum has a maximum at 293 nm, and in the UVA region above 340 nm the relative carcinogenicity per J/m2 drops to about 10(-4) of this maximum. The effects of an ozone depletion on solar UV doses weighted with these different action spectra are compared: the erythemal and SCUP weighted dose come out as least sensitive with a 1.3% and 1.4% increase, respectively, for every 1% decrease in ozone. PMID:7597292

  1. Smoking Harms Black Americans' Kidneys, Study Suggests

    MedlinePlus

    ... medlineplus/news/fullstory_159032.html Smoking Harms Black Americans' Kidneys, Study Suggests Researchers say inflammation or cigarette ... a significant risk to kidney health for black Americans, new research suggests. The study included more than ...

  2. Intestinal absorption and biomagnification of organochlorines

    SciTech Connect

    Gobas, F.A.P.C. ); McCorquodale, J.R.; Haffner, G.D. )

    1993-03-01

    Dietary uptake rates of several organochlorines from diets with different lipid contents were measured in goldfish (Carassius auratus) to investigate the mechanism of intestinal absorption and biomagnification of organic chemical. The results suggest that intestinal absorption is predominantly controlled by chemical diffusion rather than lipid cotransport. Data for chemical uptake in human infants are presented to illustrate that biomagnification is caused by the digestion of food in the gastrointestinal tract. The findings are discussed in the context of two conflicting theories for the mechanism of biomagnification, and a mechanistic model is presented for the dietary uptake and biomagnification of organic chemicals in fish and mammals.

  3. Subbarrier absorption in a stationary superlattice

    NASA Technical Reports Server (NTRS)

    Arutyunyan, G. M.; Nerkararyan, K. V.

    1984-01-01

    The calculation of the interband absorption coefficient was carried out in the classical case, when the frequency of light was assumed to bind two miniband subbarrier states of different bands. The influence of two dimensional Mott excitons on this absorption was studied and a comparison was made with the experiment. All of these considerations were done taking into account the photon wave vector (the phase spatial heterogeneity). The basic traits of the energy spectra of superlattice semiconductors, their kinetic and optical properties, and possible means of electromagnetic wave intensification were examined. By the density matrix method, a theory of electrical and electromagnetic properties of superlattices was suggested.

  4. Revisiting the total ion yield x-ray absorption spectra of liquid water microjets

    SciTech Connect

    Saykally, Richard J; Cappa, Chris D.; Smith, Jared D.; Wilson, Kevin R.; Saykally, Richard J.

    2008-02-16

    Measurements of the total ion yield (TIY) x-ray absorption spectrum (XAS) of liquid water by Wilson et al. (2002 J. Phys.: Condens. Matter 14 L221 and 2001 J. Phys. Chem. B 105 3346) have been revisited in light of new experimental and theoretical efforts by our group. Previously, the TIY spectrum was interpreted as a distinct measure of the electronic structure of the liquid water surface. However, our new results indicate that the previously obtained spectrum may have suffered from as yet unidentified experimental artifacts. Although computational results indicate that the liquid water surface should exhibit a TIY-XAS that is fundamentally distinguishable from the bulk liquid XAS, the new experimental results suggest that the observable TIY-XAS is actually nearly identical in appearance to the total electron yield (TEY-)XAS, which is a bulk probe. This surprising similarity between the observed TIY-XAS and TEY-XAS likely results from large contributions from x-ray induced electron stimulated desorption of ions, and does not necessarily indicate that the electronic structure of the bulk liquid and liquid surface are identical.

  5. New SCIAMACHY Solar Reference Spectrum

    NASA Astrophysics Data System (ADS)

    Hilbig, Tina; Bramstedt, Klaus; Weber, Mark; Burrows, John P.

    2016-04-01

    The Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) aboard ESA's ENVISAT satellite platform was operating from 2002 until 2012. It was designed to measure the radiance backscattered from the Earth and hence determine total columns and vertical profiles of atmospheric trace gas species. Furthermore SCIAMACHY performed daily sun observations via a diffuser. Solar spectra in the wavelength range from 212 nm to 1760 nm and two narrow bands from 1930 to 2040 nm and 2260 to 2380 nm are measured with a spectral resolution of 0,2 to 1,5 nm in the different channels. Recent developments in the SCIAMACHY calibration (e.g. a physical model of the scanner unit including degradation effects, and an on-ground to in-flight correction using the on-board white light source (WLS)) are used for the generation of a new SCIAMACHY solar reference spectrum as a first step towards a 10 years time series of solar spectral irradiance (SSI) data. For validation comparisons with other solar reference spectra are performed.

  6. Broad spectrum solar cell

    DOEpatents

    Walukiewicz, Wladyslaw; Yu, Kin Man; Wu, Junqiao; Schaff, William J.

    2007-05-15

    An alloy having a large band gap range is used in a multijunction solar cell to enhance utilization of the solar energy spectrum. In one embodiment, the alloy is In.sub.1-xGa.sub.xN having an energy bandgap range of approximately 0.7 eV to 3.4 eV, providing a good match to the solar energy spectrum. Multiple junctions having different bandgaps are stacked to form a solar cell. Each junction may have different bandgaps (realized by varying the alloy composition), and therefore be responsive to different parts of the spectrum. The junctions are stacked in such a manner that some bands of light pass through upper junctions to lower junctions that are responsive to such bands.

  7. Quasi-Fermi level splitting and sub-bandgap absorptivity from semiconductor photoluminescence

    SciTech Connect

    Katahara, John K.; Hillhouse, Hugh W.

    2014-11-07

    A unified model for the direct gap absorption coefficient (band-edge and sub-bandgap) is developed that encompasses the functional forms of the Urbach, Thomas-Fermi, screened Thomas-Fermi, and Franz-Keldysh models of sub-bandgap absorption as specific cases. We combine this model of absorption with an occupation-corrected non-equilibrium Planck law for the spontaneous emission of photons to yield a model of photoluminescence (PL) with broad applicability to band-band photoluminescence from intrinsic, heavily doped, and strongly compensated semiconductors. The utility of the model is that it is amenable to full-spectrum fitting of absolute intensity PL data and yields: (1) the quasi-Fermi level splitting, (2) the local lattice temperature, (3) the direct bandgap, (4) the functional form of the sub-bandgap absorption, and (5) the energy broadening parameter (Urbach energy, magnitude of potential fluctuations, etc.). The accuracy of the model is demonstrated by fitting the room temperature PL spectrum of GaAs. It is then applied to Cu(In,Ga)(S,Se){sub 2} (CIGSSe) and Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSSe) to reveal the nature of their tail states. For GaAs, the model fit is excellent, and fitted parameters match literature values for the bandgap (1.42 eV), functional form of the sub-bandgap states (purely Urbach in nature), and energy broadening parameter (Urbach energy of 9.4 meV). For CIGSSe and CZTSSe, the model fits yield quasi-Fermi leveling splittings that match well with the open circuit voltages measured on devices made from the same materials and bandgaps that match well with those extracted from EQE measurements on the devices. The power of the exponential decay of the absorption coefficient into the bandgap is found to be in the range of 1.2 to 1.6, suggesting that tunneling in the presence of local electrostatic potential fluctuations is a dominant factor contributing to the sub-bandgap absorption by either purely electrostatic (screened Thomas-Fermi) or

  8. Separating higher-order nonlinearities in transient absorption microscopy

    NASA Astrophysics Data System (ADS)

    Wilson, Jesse W.; Anderson, Miguel; Park, Jong Kang; Fischer, Martin C.; Warren, Warren S.

    2015-08-01

    The transient absorption response of melanin is a promising optically-accessible biomarker for distinguishing malignant melanoma from benign pigmented lesions, as demonstrated by earlier experiments on thin sections from biopsied tissue. The technique has also been demonstrated in vivo, but the higher optical intensity required for detecting these signals from backscattered light introduces higher-order nonlinearities in the transient response of melanin. These components that are higher than linear with respect to the pump or the probe introduce intensity-dependent changes to the overall response that complicate data analysis. However, our data also suggest these nonlinearities might be advantageous to in vivo imaging, in that different types of melanins have different nonlinear responses. Therefore, methods to separate linear from nonlinear components in transient absorption measurements might provide additional information to aid in the diagnosis of melanoma. We will discuss numerical methods for analyzing the various nonlinear contributions to pump-probe signals, with the ultimate objective of real time analysis using digital signal processing techniques. To that end, we have replaced the lock-in amplifier in our pump-probe microscope with a high-speed data acquisition board, and reprogrammed the coprocessor field-programmable gate array (FPGA) to perform lock-in detection. The FPGA lock-in offers better performance than the commercial instrument, in terms of both signal to noise ratio and speed. In addition, the flexibility of the digital signal processing approach enables demodulation of more complicated waveforms, such as spread-spectrum sequences, which has the potential to accelerate microscopy methods that rely on slow relaxation phenomena, such as photo-thermal and phosphorescence lifetime imaging.

  9. Neuromyelitis optica spectrum disorders

    PubMed Central

    Sepúlveda, Maria; Armangué, Thaís; Sola-Valls, Nuria; Arrambide, Georgina; Meca-Lallana, José E.; Oreja-Guevara, Celia; Mendibe, Mar; Alvarez de Arcaya, Amaya; Aladro, Yolanda; Casanova, Bonaventura; Olascoaga, Javier; Jiménez-Huete, Adolfo; Fernández-Fournier, Mireya; Ramió-Torrentà, Lluis; Cobo-Calvo, Alvaro; Viñals, Montserrat; de Andrés, Clara; Meca-Lallana, Virginia; Cervelló, Angeles; Calles, Carmen; Rubio, Manuel Barón; Ramo-Tello, Cristina; Caminero, Ana; Munteis, Elvira; Antigüedad, Alfredo R.; Blanco, Yolanda; Villoslada, Pablo; Montalban, Xavier; Graus, Francesc

    2016-01-01

    Objective: To (1) determine the value of the recently proposed criteria of neuromyelitis optica (NMO) spectrum disorder (NMOSD) that unify patients with NMO and those with limited forms (NMO/LF) with aquaporin-4 immunoglobulin G (AQP4-IgG) antibodies; and (2) investigate the clinical significance of the serologic status in patients with NMO. Methods: This was a retrospective, multicenter study of 181 patients fulfilling the 2006 NMO criteria (n = 127) or NMO/LF criteria with AQP4-IgG (n = 54). AQP4-IgG and myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG) antibodies were tested using cell-based assays. Results: Patients were mainly white (86%) and female (ratio 6.5:1) with median age at onset 39 years (range 10–77). Compared to patients with NMO and AQP4-IgG (n = 94), those with NMO/LF presented more often with longitudinally extensive transverse myelitis (LETM) (p < 0.001), and had lower relapse rates (p = 0.015), but similar disability outcomes. Nonwhite ethnicity and optic neuritis presentation doubled the risk for developing NMO compared with white race (p = 0.008) or LETM presentation (p = 0.008). Nonwhite race (hazard ratio [HR] 4.3, 95% confidence interval [CI] 1.4–13.6) and older age at onset were associated with worse outcome (for every 10-year increase, HR 1.7, 95% CI 1.3–2.2). Patients with NMO and MOG-IgG (n = 9) had lower female:male ratio (0.8:1) and better disability outcome than AQP4-IgG-seropositive or double-seronegative patients (p < 0.001). Conclusions: In patients with AQP4-IgG, the similar outcomes regardless of the clinical phenotype support the unified term NMOSD; nonwhite ethnicity and older age at onset are associated with worse outcome. Double-seronegative and AQP4-IgG-seropositive NMO have a similar clinical outcome. The better prognosis of patients with MOG-IgG and NMO suggests that phenotypic and serologic classification is useful. PMID:27144216

  10. Interstellar X-Ray Absorption Spectroscopy of the Crab Pulsar with the LETGS

    NASA Technical Reports Server (NTRS)

    Paerels, Frits; Weisskopf, Martin C.; Tennant, Allyn F.; ODell, Stephen L.; Swartz, Douglas A.; Kahn, Steven M.; Behar, Ehud; Becker, Werner; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    We study the interstellar X-ray absorption along the line of sight to the Crab Pulsar. The Crab was observed with the Low Energy Transmission Grating Spectrometer on the Chandra X-ray Observatory, and the pulsar, a point source, produces a full resolution spectrum. The continuum spectrum appears smooth, and we compare its parameters with other measurements of the pulsar spectrum. The spectrum clearly shows absorption edges due to interstellar Ne, Fe, and O. The O edge shows spectral structure that is probably due to O bound in molecules or dust. We search for near-edge structure (EXAFS) in the O absorption spectrum. The Fe L absorption spectrum is largely due to a set of unresolved discrete n=2-3 transitions in neutral or near-neutral Fe, and we analyze it using a new set of dedicated atomic structure calculations, which provide absolute cross sections. In addition to being interesting in its own right, the ISM absorption needs to be understood in quantitative detail in order to derive spectroscopic constraints on possible soft thermal radiation from the pulsar.

  11. Corrosion Problems in Absorption Chillers

    ERIC Educational Resources Information Center

    Stetson, Bruce

    1978-01-01

    Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

  12. Wind speed power spectrum analysis for Bushland, Texas

    SciTech Connect

    Eggleston, E.D.

    1996-12-31

    Numerous papers and publications on wind turbulence have referenced the wind speed spectrum presented by Isaac Van der Hoven in his article entitled Power Spectrum of Horizontal Wind Speed Spectrum in the Frequency Range from 0.0007 to 900 Cycles per Hour. Van der Hoven used data measured at different heights between 91 and 125 meters above the ground, and represented the high frequency end of the spectrum with data from the peak hour of hurricane Connie. These facts suggest we should question the use of his power spectrum in the wind industry. During the USDA - Agricultural Research Service`s investigation of wind/diesel system power storage, using the appropriate wind speed power spectrum became a significant issue. We developed a power spectrum from 13 years of hourly average data, 1 year of 5 minute average data, and 2 particularly gusty day`s 1 second average data all collected at a height of 10 meters. While the general shape is similar to the Van der Hoven spectrum, few of his peaks were found in the Bushland spectrum. While higher average wind speeds tend to suggest higher amplitudes in the high frequency end of the spectrum, this is not always true. Also, the high frequency end of the spectrum is not accurately described by simple wind statistics such as standard deviation and turbulence intensity. 2 refs., 5 figs., 1 tab.

  13. NREL Spectrum of Innovation

    ScienceCinema

    None

    2013-05-29

    There are many voices calling for a future of abundant clean energy. The choices are difficult and the challenges daunting. How will we get there? The National Renewable Energy Laboratory integrates the entire spectrum of innovation including fundamental science, market relevant research, systems integration, testing and validation, commercialization and deployment. The innovation process at NREL is interdependent and iterative. Many scientific breakthroughs begin in our own laboratories, but new ideas and technologies come to NREL at any point along the innovation spectrum to be validated and refined for commercial use.

  14. Bottomonium spectrum revisited

    NASA Astrophysics Data System (ADS)

    Segovia, Jorge; Ortega, Pablo G.; Entem, David R.; Fernández, Francisco

    2016-04-01

    We revisit the bottomonium spectrum motivated by the recently exciting experimental progress in the observation of new bottomonium states, both conventional and unconventional. Our framework is a nonrelativistic constituent quark model which has been applied to a wide range of hadronic observables from the light to the heavy quark sector, and thus the model parameters are completely constrained. Beyond the spectrum, we provide a large number of electromagnetic, strong and hadronic decays in order to discuss the quark content of the bottomonium states and give more insights about a better way to determine their properties experimentally.

  15. Improving VHF Spectrum Utilization

    NASA Technical Reports Server (NTRS)

    Andro, Monty; Orr, Richard; Foore, Larry; Sheehe, Charles; Freeman, Mark; Nguyen, Thanh; Bretmersky, Steven; Laberge, Chuck; Buchanan, David

    2004-01-01

    Limited VHF communications system capacity and increasing air traffic results in congestion of the aviation VHF spectrum. The voice communications errors and delayed channel access create system congestion and air traffic delays. Regulatory subdivision of bands for specific functions limits flexibility in the frequency usage. The objective of this viewgraph presentation is to identify near/mid/far term technologies to improve the performance and spectrum efficiency of current and emerging VHF communications systems. Select technologies with the highest potential, perform research and development to bring them to implementation stage.

  16. VARIATIONS OF ABSORPTION TROUGHS IN THE QUASAR SDSS J125216.58+052737.7

    SciTech Connect

    Chen, Zhi-Fu; Qin, Yi-Ping

    2015-01-20

    In this work, we analyze the spectra of quasar J125216.58+052737.7 (z {sub em} = 1.9035) which was observed by SDSS-I/II on 2003 January 30 and by BOSS on 2011 April 2. Both the continuum and the absorption spectra of this quasar show obvious variations between the two epochs. In the SDSS-I/II spectrum, we detect 8 C IV λλ1548,1551 absorption systems, which are detected at z {sub abs} = 1.9098, 1.8948, 1.8841, 1.8770, 1.8732, 1.8635, 1.8154, and 1.7359, respectively, and one Mg II λλ2796,2803 absorption system at z {sub abs} = 0.9912. Among these absorption systems, two C IV λλ1548,1551 absorption systems at z {sub abs} = 1.9098 and 1.7359 and the Mg II λλ2796,2803 absorption system are imprinted on the BOSS spectrum as well, and have similar absorption strengths when compared to those measured from the SDSS-I/II spectrum. Three C IV λλ1548,1551 absorption systems at z {sub abs} = 1.8948, 1.8841, and 1.8770 are also detected in the BOSS spectrum, while their absorption strengths are much weaker than those measured from the SDSS-I/II spectrum; three systems at z {sub abs} = 1.8732, 1.8635, and 1.8154 disappeared from the BOSS spectrum. Based on the variability analysis, the absorption systems that disappeared and weakened are likely to be intrinsic to the quasar. If these intrinsic absorption gases are blown away from the central region of the quasar, with respect to the quasar system, the absorption systems that disappeared would have separation velocities of 3147 kms{sup –1}, 4161 km s{sup –1}, and 9241 km s{sup –1}, while the absorption systems that weakened would have separation velocities of 900 km s{sup –1}, 2011 km s{sup –1}, and 2751 km s{sup –1}. Well-coordinated variations of the six C IV λλ1548,1551 absorption systems that disappeared and weakened, occurring on a timescale of 1026.7 days at the quasar rest frame, can be interpreted as a result of global changes in the ionization state of the absorbing gas.

  17. Empathic features of absorption and incongruence.

    PubMed

    Wickramasekera, Ian E

    2007-07-01

    A study was undertaken to examine whether empathy could be related to absorption and incongruence (repressive coping). The participants were 71 graduate students who completed measures of empathy, absorption, and incongruence (repressive coping). The results confirmed a previous finding that empathy appears positively related to absorption (r = .42, p < .001). The results also suggest that affective components of empathy are inversely related to repressive coping (r = -.29, p < .05) while cognitive components are positively related to the social desirability aspects of incongruence (r = .31, p < .01). The findings are collectively discussed in terms of the Empathic Involvement Hypothesis of Hypnosis (Wickramasekera II, 2001), the Four-factor theory of Repressive Coping (Eysenck, 1997), Incongruence (Rogers, 1957), and the High Risk Model of Threat Perception (I. E. Wickramasekera I, 1998). PMID:17685245

  18. Acoustic Absorption Characteristics of People.

    ERIC Educational Resources Information Center

    Kingsbury, H. F.; Wallace, W. J.

    1968-01-01

    The acoustic absorption characteristics of informally dressed college students in typical classroom seating are shown to differ substantially from data for formally dressed audiences in upholstered seating. Absorption data, expressed as sabins per person or absorption coefficient per square foot, shows that there is considerable variation between…

  19. Economic strategies of plant absorptive roots vary with root diameter

    NASA Astrophysics Data System (ADS)

    Kong, D. L.; Wang, J. J.; Kardol, P.; Wu, H. F.; Zeng, H.; Deng, X. B.; Deng, Y.

    2016-01-01

    Plant roots typically vary along a dominant ecological axis, the root economics spectrum, depicting a tradeoff between resource acquisition and conservation. For absorptive roots, which are mainly responsible for resource acquisition, we hypothesized that root economic strategies differ with increasing root diameter. To test this hypothesis, we used seven plant species (a fern, a conifer, and five angiosperms from south China) for which we separated absorptive roots into two categories: thin roots (thickness of root cortex plus epidermis < 247 µm) and thick roots. For each category, we analyzed a range of root traits related to resource acquisition and conservation, including root tissue density, different carbon (C), and nitrogen (N) fractions (i.e., extractive, acid-soluble, and acid-insoluble fractions) as well as root anatomical traits. The results showed significant relationships among root traits indicating an acquisition-conservation tradeoff for thin absorptive roots while no such trait relationships were found for thick absorptive roots. Similar results were found when reanalyzing data of a previous study including 96 plant species. The contrasting economic strategies between thin and thick absorptive roots, as revealed here, may provide a new perspective on our understanding of the root economics spectrum.

  20. A study of spectrum fatigue crack propagation in two aluminum alloys. 1: Spectrum simplification

    NASA Technical Reports Server (NTRS)

    Telesman, J.; Antolovich, S. D.

    1985-01-01

    The fatigue crack propagation behavior of two commercial Al alloys was studied using spectrum loading conditions characteristics of those encountered at critical locations in high performance fighter aircraft. A tension dominated (TD) and tension compression (TC) spectrum were employed for each alloy. Using a mechanics-based analysis, it was suggested that negative loads could be eliminated for the TC spectrum for low to intermediate maximum stress intensities. The suggestion was verified by subsequent testing. Using fractographic evidence, it was suggested that a further similification in the spectra could be accomplished by eliminating low and intermediate peak load points resulting in near or below threshold maximum peak stress intensity values. It is concluded that load interactions become more important at higher stress intensities and more plasticity at the crack tip. These results suggest that a combined mechanics/fractographic mechanisms approach can be used to simplify other complex spectra.

  1. Effects of stereotypes and suggestion on memory.

    PubMed

    Shechory, Mally; Nachson, Israel; Glicksohn, Joseph

    2010-02-01

    In this study, the interactive effect of stereotype and suggestion on accuracy of memory was examined by presenting 645 participants (native Israelis and immigrants from the former Soviet Union and Ethiopia) with three versions of a story about a worker who is waiting in a manager's office for a meeting. All versions were identical except for the worker's name, which implied a Russian or an Ethiopian immigrant or a person of no ethnic origin. Each participant was presented with one version of the story. After an hour delay, the participants' memories were tested via two questionnaires that differed in terms of level of suggestion. Data analyses show that (a) when a suggestion matched the participant's stereotypical perception, the suggestion was incorporated into memory but (b) when the suggestion contradicted the stereotype, it did not influence memory. The conclusion was that recall is influenced by stereotypes but can be enhanced by compatible suggestions. PMID:18662974

  2. Hypnotizability, not suggestion, influences false memory development.

    PubMed

    Dasse, Michelle N; Elkins, Gary R; Weaver, Charles A

    2015-01-01

    Hypnotizability influences the development of false memories. In Experiment 1, participants heard a positive or negative suggestion regarding hypnosis and then listened to 8 Deese-Roediger-McDermott (DRM) false memory paradigm lists in a hypnotic state. Neither hypnosis nor prehypnotic suggestion affected memory. Highly hypnotizable participants were more accurate in recall and recognition. In Experiment 2, suggestions were delivered in the form of feedback. Participants heard a positive or negative suggestion about their performance prior to either the encoding or retrieval of 8 DRM lists. Neither accurate nor false memories were affected by the suggestion. Highly hypnotizable individuals recognized fewer critical lures if they received a negative suggestion about their performance. These results highlight the unusual role of hypnotizability in the creation of false memories. PMID:25365130

  3. Individual personality characteristics related to suggestibility.

    PubMed

    Van Hook, Cheryl W; Steele, Connie

    2002-12-01

    The current study investigated the relationship between suggestibility of memory, personality characteristics identified by the Millon Index of Personality Traits, and tolerance for ambiguity measured by MacDonald's Ambiguity Tolerance-20. 85 female and 16 male college students were assigned to either an experimental group receiving the suggestive information or a control group. Suggestibility was assessed using Lindberg's suggestibility measure consisting of a short video, followed by a questionnaire used to assess memory, and a second administration one week later. Logistical regression analyses were used to construct a model of the personality characteristics predictive of suggestibility and indicated that susceptibility to suggestive information may differ across personalities for variables such as sensing, innovating, agreeing, and low tolerance of ambiguity. PMID:12530759

  4. The Frequency Spectrum Radio.

    ERIC Educational Resources Information Center

    Howkins, John, Ed.

    1979-01-01

    This journal issue focuses on the frequency spectrum used in radio communication and on the World Administrative Radio Conference, sponsored by the International Telecommunication Union, held in Geneva, Switzerland, in the fall of 1979. Articles describe the World Administrative Radio Conference as the most important radio communication conference…

  5. Battlefield spectrum management

    NASA Astrophysics Data System (ADS)

    Sivakumar, C.

    1997-06-01

    Modern tactical communications systems rely on radios to support network and user connectivity. One of the challenges for network planners and managers is to make best use of scarce and vulnerable frequency spectrum resources to support the communication needs of war fighters. With the wide variety of Iris radio types typically to be deployed in the battlefield (ranging from high frequency to super high frequency), a comprehensive suite of tools is necessary to ensure that frequency interference is kept minimum. Without a sophisticated frequency spectrum management system, the most advanced tactical communications systems could be rendered useless, jeopardizing human life and national security. For these reasons, it is important to develop an Iris wide battlefield spectrum management capability that takes full advantage of current frequency spectrum management research and development (R&D), related tools, and supporting technology for assigning frequencies. This session briefly describes various assignment strategies being adopted in the Iris BFSM for overcoming cosite/collocated/farsite interferences along with the propagation models [from high frequency (HF) to super high frequency (SHF)] used for the assignment of frequencies. Also a brief thread outlining the process for generating frequency allocation/assignment request and analysis of frequency interference is discussed.

  6. Charging for Spectrum Use.

    ERIC Educational Resources Information Center

    Geller, Henry; Lampert, Donna

    This paper, the third in a series exploring future options for public policy in the communications and information arenas, argues that the communications spectrum--e.g., public mobile service, private radio, and domestic satellites--is a valuable but limited resource that should benefit all Americans. After a background discussion, it is…

  7. Sinclair ZX Spectrum.

    ERIC Educational Resources Information Center

    Rodwell, Peter

    1982-01-01

    Describes and evaluates the hardware, software, peripheral devices, performance capabilities, and programing capacity of the Sinclair ZX Spectrum microcomputer. The computer's display system, its version of the BASIC programing language, its graphics capabilities, and the unique features of its data entry keyboard are discussed. (JL)

  8. In-vivo absorption properties of algal pigments

    NASA Astrophysics Data System (ADS)

    Bidigare, Robert R.; Ondrusek, Michael E.; Morrow, John H.; Kiefer, Dale A.

    1990-09-01

    Estimates of the in vivo specific absorption coefficients (m2 mg'; 400-750 nm, 2 nm intervals) for the major algal pigment groups (chlorophylls, carotenoids and phycobilins) are presented. "Unpackaged" absorption coefficients were initially obtained by measuring the absorption properties of pure pigment standards spectrophotometrically and "shifting" their absorption maxima to match in vivo positions. Two approaches for estimating the phytoplankton absorption coefficient (spectral reconstruction and spectral decomposition) are compared by linear regression analysis, incorporating concurrent measurements of particulate absorption and pigmentation performed in the Sargasso Sea. Results suggest that "pigment package" effects are minimal for natural assemblages of open-oceanic phytoplankton and that accessory pigments do not always co-vary with chlorophyll a over depth and time.

  9. Study on the elemental mercury absorption cross section based on differential optical absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Zheng, Haiming; Yao, Penghui

    2015-08-01

    With the method of ultraviolet absorption spectrum, the exact absorption cross-section with the light source of the low-pressure mercury lamp was determined, during which the optimum wavelength for mercury concentrations inversion was 253.69 nm, the highest detection limit was 0.177 μg/cm3, and the lowest detection limit was 0.034 μg/cm3. Furthermore, based on the differential optical absorption spectroscopy(DOAS), the relationship between the integral parameters (IP) and the concentration as well as the signal-noise ration (SNR) under the conditions of gas flow was determined and the lowest detection limit was figured out to be 0.03524 μg/cm3, providing a method of DOAS to de-noise through the comparison between the mercury concentration values produced by DOAS and that produced by the wavelet de-noising method (db5). It turned out that the differential optical absorption spectroscopy had a strong anti-interference ability, while the wavelet de-noising method was not suitable for measuring the trace concentration change.

  10. Absorption heat pumps

    NASA Astrophysics Data System (ADS)

    Huhtinen, M.; Heikkilae, M.; Andersson, R.

    1987-03-01

    The aim of the study was to analyze the technical and economic feasibility of absorption heat pumps in Finland. The work was done as a case study: the technical and economic analyses have been carried out for six different cases, where in each the suitable size and type of the heat pump plant and the auxiliary components and connections were specified. The study also detailed the costs concerning the procurement, installation and test runs of the machinery, as well as the savings in energy costs incurred by the introduction of the plant. Conclusions were drawn of the economic viability of the applications studied. The following cases were analyzed: heat recovery from flue gases and productin of district heat in plants using peat, natural gas, and municipal wastes as a fuel. Heat recovery in the pulp and paper industry for the upgrading of pressure of secondary steam and for the heating of white liquor and combustion and drying the air. Heat recovery in a peat-fulled heat and power plant from flue gases that have been used for the drying of peat. According to the study, the absorption heat pump suits best to the production of district heat, when the heat source is the primary energy is steam produced by the boiler. Included in the flue as condensing is the purification of flue gases. Accordingly, benefit is gained on two levels in thick applications. In heat and power plants the use of absorption heat pumps is less economical, due to the fact that the steam used by the pump reduces the production of electricity, which is rated clearly higher than heat.

  11. Scattering with absorptive interaction

    NASA Astrophysics Data System (ADS)

    Cassing, W.; Stingl, M.; Weiguny, A.

    1982-07-01

    The S matrix for a wide class of complex and nonlocal potentials is studied, with special attention given to the motion of singularities in the complex k plane as a function of the imaginary coupling strength. Modifications of Levinson's theorem are obtained and discussed. Analytic approximations to the S matrix in the vicinity of narrow resonances are exhibited and compared to numerical results of resonating-group calculations. The problem of defining resonances in the case of complex interactions is discussed, making contact with the usual analysis of scattering in terms of Argand diagrams. NUCLEAR REACTIONS Scattering theory, S matrix for absorptive potentials.

  12. Ultraviolet absorption hygrometer

    DOEpatents

    Gersh, M.E.; Bien, F.; Bernstein, L.S.

    1986-12-09

    An ultraviolet absorption hygrometer is provided including a source of pulsed ultraviolet radiation for providing radiation in a first wavelength region where water absorbs significantly and in a second proximate wavelength region where water absorbs weakly. Ultraviolet radiation in the first and second regions which has been transmitted through a sample path of atmosphere is detected. The intensity of the radiation transmitted in each of the first and second regions is compared and from this comparison the amount of water in the sample path is determined. 5 figs.

  13. Ultraviolet absorption hygrometer

    DOEpatents

    Gersh, Michael E.; Bien, Fritz; Bernstein, Lawrence S.

    1986-01-01

    An ultraviolet absorption hygrometer is provided including a source of pulsed ultraviolet radiation for providing radiation in a first wavelength region where water absorbs significantly and in a second proximate wavelength region where water absorbs weakly. Ultraviolet radiation in the first and second regions which has been transmitted through a sample path of atmosphere is detected. The intensity of the radiation transmitted in each of the first and second regions is compared and from this comparison the amount of water in the sample path is determined.

  14. The matter power spectrum from the Lyα forest: an optical depth estimate

    NASA Astrophysics Data System (ADS)

    Zaroubi, S.; Viel, M.; Nusser, A.; Haehnelt, M.; Kim, T.-S.

    2006-06-01

    We measure the matter power spectrum from 31 Lyα spectra spanning the redshift range of 1.6-3.6. The optical depth, τ, for Lyα absorption of the intergalactic medium is obtained from the flux using the inversion method of Nusser & Haehnelt. The optical depth is converted to density by using a simple power-law relation, τ ~ (1 + δ)α. The non-linear 1D power spectrum of the gas density is then inferred with a method that makes simultaneous use of the one- and two-point statistics of the flux and compared against theoretical models with a likelihood analysis. A cold dark matter model with standard cosmological parameters fits the data well. The power-spectrum amplitude is measured to be (assuming a flat Universe), σ8 = (0.92 +/- 0.09) × (Ωm/0.3)-0.3, with α varying in the range of 1.56-1.8 with redshift. Enforcing the same cosmological parameters in all four redshift bins, the likelihood analysis suggests some evolution in the temperature-density relation and the thermal smoothing length of the gas. The inferred evolution is consistent with that expected if reionization of HeII occurred at z ~ 3.2. A joint analysis with the Wilkinson Microwave Anisotropy Probe results together with a prior on the Hubble constant as suggested by the Hubble Space Telescope key project data, yields values of Ωm and σ8 that are consistent with the cosmological concordance model. We also perform a further inversion to obtain the linear 3D power spectrum of the matter density fluctuations.

  15. 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.

  16. An HST COS 'SNAPSHOT' spectrum of the K supergiant λ Vel (K4Ib-II)

    SciTech Connect

    Carpenter, Kenneth G.; Harper, Graham M.; Kober, Gladys; Nielsen, Krister E.; Wahlgren, Glenn M.

    2014-10-10

    We present a far-ultraviolet spectrum of the K4 Ib-II supergiant λ Vel obtained with the Hubble Space Telescope's Cosmic Origins Spectrograph (COS) as a part of the SNAPshot program 'SNAPing coronal iron' (GO 11687). The observation covers a wavelength region (1326-1467 Å) not previously recorded for λ Vel at a spectral resolving power of R ∼ 20,000 and displays strong emission and absorption features, superposed on a bright chromospheric continuum. Fluorescent excitation is responsible for much of the observed emission, mainly powered by strong H I Lyα and the O I (UV 2) triplet emission near λ1304. The molecular CO and H{sub 2} fluorescences are weaker than in the early-K giant α Boo while the Fe II and Cr II lines, also pumped by H I Lyα, are stronger in λ Vel. This pattern of relative line strengths between the two stars is explained by the lower iron-group element abundance in α Boo, which weakens that star's Fe II and Cr II emission without reducing the molecular fluorescences. The λ Vel spectrum shows fluorescent Fe II, Cr II, and H{sub 2} emission similar to that observed in the M supergiant α Ori, but more numerous well-defined narrow emissions from CO. The additional CO emissions are visible in the spectrum of λ Vel since that star does not have the cool, opaque circumstellar shells that surround α Ori and produce broad circumstellar CO (A-X) band absorptions that hide those emissions in the cooler star. The presence of Si IV emission in λ Vel indicates a ∼8 × 10{sup 4} K plasma that is mixed into the cooler chromosphere. Evidence of the stellar wind is seen in the C II λλ1334,1335 lines and in the blueshifted Fe II and Ni II wind absorption lines. Line modeling using Sobolev with Exact Integration for the C II lines indicates a larger terminal velocity (∼45 versus ∼30 km s{sup –1}) and turbulence (∼27 versus <21 km s{sup –1}) with a more quickly accelerating wind (β = 0.35 versus 0.7) at the time of this COS observation in

  17. [UV-Vis spectrum characteristics of phycocyanin in water from Taihu lake].

    PubMed

    Zhang, Jing; Wei, Yu-Chun; Wang, Guo-Xiang; Cheng, Chun-Mei; Xia, Xiao-Rui

    2014-05-01

    The present paper analyzed the UV-Vis spectrum characteristics of phycocyanin extracted from 75 water samples around Meiliang Bay of Taihu Lake, China in spring, summer and autumn, 2011, taking standard sample of phycocyanin, Micro-cystic aeruginosa and Anabaena cultured indoor as the reference, and discussed the difference and relation of spectrum among water samples, standard sample and single algae samples. According to the number of absorption peak in the wavelength range from 500 to 700 nm, phycocyanin spectrum of water sampling in Taihu Lake can be divided into three patterns: no peak, single peak and two peaks. In the first pattern, the absorbance changed smoothly and no absorption peak was observed around 620 nm. Depending on the absorption difference in the wavelength range from 300 to 450 nm, this pattern can be divided into type I and type II. Type I only had a absorption peak near 260 nm, with the similar spectrum of chromophoric dissolved organic matter (CDOM) in the wavelength range from 250 to 800 nm. Type II had absorption peak respectively near 260 and 330 nm. In single peak pattern and two peaks pattern, significant absorption peak of phycocyanin appeared around 620 nm. Compared to the other patterns, single peak pattern was more similar to that of standard sample and single algae samples, but different in their maximum absorption peaks position and relative absorption intensity in the wavelength range of 250 approximately 300, 300 approximately 450 and 500 approximately 700 nm, because of different algae species and purity after extraction. In the two peaks pattern, another absorption peak appeared at 670nm, with the absorption shoulder from 350 to 450 nm, and shared the absorption characteristics of phycocyanin and chlorophyll complex protein. The research can provide a basic support for the phycocyanin quantitation and blooms monitoring in Taihu Lake. PMID:25095426

  18. Maltreated Children's Memory: Accuracy, Suggestibility, and Psychopathology

    ERIC Educational Resources Information Center

    Eisen, Mitchell L.; Goodman, Gail S.; Qin, Jianjian; Davis, Suzanne; Crayton, John

    2007-01-01

    Memory, suggestibility, stress arousal, and trauma-related psychopathology were examined in 328 3- to 16-year-olds involved in forensic investigations of abuse and neglect. Children's memory and suggestibility were assessed for a medical examination and venipuncture. Being older and scoring higher in cognitive functioning were related to fewer…

  19. Suggested Learnings: Consumer and Homemaking Education.

    ERIC Educational Resources Information Center

    Edmondson, Dorothy Jean; Swanson, Bettye B.

    The guide presents suggested learning concepts, experiences, and references for home economics educators in the planning and organization of secondary level consumer and homemaking programs. The suggestions are based on questionnaires and interviews with teachers and administrators involved in this program. The guide's main focus is on the process…

  20. Study on the THz spectrum of methamphetamine

    NASA Astrophysics Data System (ADS)

    Ning, Li; Shen, Jingling; Jinhai, Sun; Laishun, Liang; Xu, Xiaoyu; Lu, Meihong; Yan, Jia

    2005-09-01

    The spectral absorption features of methamphetamine (MA), one of the most widely consumed illicit drugs in the world, are studied experimentally by Terahertz (THz) time-domain spectroscopy (THz-TDS), and the characteristic absorption spectra are obtained in the range of 0.2 to 2.6 THz. The vibrational frequencies are calculated using the density functional theory (DFT). Theoretical results show significant agreement with experimental results, and identification of vibrational modes are given. The calculated results further confirm that the characteristic frequencies come from the collective vibrational modes. The results suggest that use of the THz-TDS technique can be an effective way to inspect for illicit drugs.

  1. Genetic Testing for Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Bauer, Sarah C.; Msall, Michael E.

    2011-01-01

    Children with autism spectrum disorders (ASD) have unique developmental and behavioral phenotypes, and they have specific challenges with communication, social skills, and repetitive behaviors. At this time, no single etiology for ASD has been identified. However, evidence from family studies and linkage analyses suggests that genetic factors play…

  2. Resonant Nanophotonic Spectrum Splitting for Ultrathin Multijunction Solar Cells

    PubMed Central

    2015-01-01

    We present an approach to spectrum splitting for photovoltaics that utilizes the resonant optical properties of nanostructures for simultaneous voltage enhancement and spatial separation of different colors of light. Using metal–insulator–metal resonators commonly used in broadband metamaterial absorbers we show theoretically that output voltages can be enhanced significantly compared to single-junction devices. However, the approach is general and works for any type of resonator with a large absorption cross section. Due to its resonant nature, the spectrum splitting occurs within only a fraction of the wavelength, as opposed to traditional spectrum splitting methods, where many wavelengths are required. Combining nanophotonic spectrum splitting with other nanophotonic approaches to voltage enhancements, such as angle restriction and concentration, may lead to highly efficient but deeply subwavelength photovoltaic devices. PMID:26322319

  3. Methane Absorption Coefficients in the 750-940 nm region derived from Intracavity Laser Absorption Spectral Measurements

    NASA Astrophysics Data System (ADS)

    O'Brien, J. J.

    2002-09-01

    The absorption spectrum of methane has been recorded in the visible to near-IR region using the intracavity laser spectroscopy technique. Spectra are recorded at high spectral resolution for narrow overlapping intervals in the region for room and 77 K temperature methane samples. After spectra are deconvolved for the instrument function, absorption coefficients are derived. These will be presented (750-940 nm for room temperature methane; 850-920 nm for 77 K methane) and compared with results reported by other workers. Future work in this area also will be indicated. Support from NASA's Planetary Atmospheres Program (NAG5-6091 and a Major Equipment Grant) is gratefully acknowledged.

  4. Novel patterns of torsion-inversion-rotation energy levels in the ν11 asymmetric CH-stretch spectrum of methylamine.

    PubMed

    Dawadi, Mahesh B; Michael Lindsay, C; Chirokolava, Andrei; Perry, David S; Xu, Li-Hong

    2013-03-14

    The high-resolution infrared spectrum of methylamine (CH3NH2) has been recorded using slit-jet direct absorption spectroscopy in the ν11 CH-stretch region (2965-3005 cm(-1)) with a resolution of 0.0025 cm(-1). The 621 lines assigned by ground state combination differences represent 27 substates with |K(')| ≤ 2 for the A, B, E1, and E2 symmetries. The spectrum of CH3NH2 is complicated by torsion and inversion tunneling connecting six equivalent minima. The upper states K(') = 0, ± 1 for E1 and E2 are substantially perturbed by "dark" states. The result in the spectrum is multiplets of 2 or 3 states with mixed bright∕dark character. The analysis of the spectrum reveals two qualitative differences in the energy level pattern relative to the vibrational ground state and relative to available data on the lower frequency vibrations (NH2 wag and CN stretch). First at J(') = 0, there is a different ordering of the levels connected by torsion-inversion tunneling. Second, the low-J splittings indicative of torsion-rotation coupling are greatly reduced in the ν11 excited state relative to the vibrational ground state for both the E1 and E2 species, suggesting the partial suppression of torsional tunneling in the ν11 CH-stretch excited state. PMID:23514487

  5. A SURVEY OF ALKALI LINE ABSORPTION IN EXOPLANETARY ATMOSPHERES

    SciTech Connect

    Jensen, Adam G.; Redfield, Seth; Endl, Michael; Cochran, William D.; Koesterke, Lars; Barman, Travis S. E-mail: sredfield@wesleyan.edu E-mail: wdc@astro.as.utexas.edu E-mail: barman@lowell.edu

    2011-12-20

    We obtained over 90 hr of spectroscopic observations of four exoplanetary systems with the Hobby-Eberly Telescope. Observations were taken in transit and out of transit, and we analyzed the differenced spectra-i.e., the transmission spectra-to inspect it for absorption at the wavelengths of the neutral sodium (Na I) doublet at {lambda}{lambda}5889, 5895 and neutral potassium (K I) at {lambda}7698. We used the transmission spectrum at Ca I {lambda}6122-which shows strong stellar absorption but is not an alkali metal resonance line that we expect to show significant absorption in these atmospheres-as a control line to examine our measurements for systematic errors. We use an empirical Monte Carlo method to quantify these systematic errors. In a reanalysis of the same data set using a reduction and analysis pipeline that was derived independently, we confirm the previously seen Na I absorption in HD 189733b at a level of (- 5.26 {+-} 1.69) Multiplication-Sign 10{sup -4} (the average value over a 12 A integration band to be consistent with previous authors). Additionally, we tentatively confirm the Na I absorption seen in HD 209458b (independently by multiple authors) at a level of (- 2.63 {+-} 0.81) Multiplication-Sign 10{sup -4}, though the interpretation is less clear. Furthermore, we find Na I absorption of (- 3.16 {+-} 2.06) Multiplication-Sign 10{sup -4} at <3{sigma} in HD 149026b; features apparent in the transmission spectrum are consistent with real absorption and indicate this may be a good target for future observations to confirm. No other results (Na I in HD 147506b and Ca I and K I in all four targets) are significant to {>=}3{sigma}, although we observe some features that we argue are primarily artifacts.

  6. Diode laser absorption sensors for combustion control

    NASA Astrophysics Data System (ADS)

    Xin, Zhou

    Combustion is the most widely used energy conversion technique in the world. Diode-laser absorption sensors offer significant opportunities and advantages for in situ measurements of multiple combustion parameters such as temperature and species concentration due to their high sensitivity, high spectral resolution, fast time response, robustness and non-intrusive character. The overall objective of this thesis is to design and develop time-resolved and real-time tunable diode laser sensors with the potential for combustion control. A crucial element in the design of a tunable-diode-laser optical-absorption-based sensor is the selection of optimum transitions. The strategy and spectroscopic criteria for selecting optimum wavelength regions and absorption line combinations are developed. The development of this design-rule approach establishes a new paradigm to optimize tunable diode laser sensors for target applications. The water vapor spectrum in the 1-2 mum near-infrared region is systematically analyzed to find the best absorption transition pairs for sensitive measurement of temperature in the target combustion environment using a single tunable diode laser. Two sensors are developed in this work. The first sensor is a 1.8 mum, single-laser temperature sensor based on direct absorption scans. Successful time-resolved measurements in a variety of laboratory and practical devices are presented and used to identify potential improvements, and design rules for a second-generation sensor are developed based on the lessons learned. The second generation sensor is a 1.4 mum, single-laser temperature sensor using water vapor absorption detected by wavelength-modulation spectroscopy (WMS), which facilitates rapid data analysis and a 2 kHz real-time data rate in the combustion experiments reported here. Demonstration experiments in a heated cell and a forced Hencken burner confirm the sensitivity and accuracy of the sensors. The first application of TDL thermometry to a

  7. Induction Technique: Beyond Simple Response to Suggestion.

    PubMed

    Barabasz, Arreed; Barabasz, Marianne

    2016-10-01

    The hypnotic induction is intended to induce hypnosis. This implies that what is sought is intended to go beyond what might be wrought by mere suggestion, expectancy, and social influence. The experimentally controlled research showing that the induction makes a difference and how small changes in wording of suggestions can produce orthogonal responses is briefly reviewed. This article explains the principles of induction and three critical phases of hypnotic induction in detail. An arm levitation scripted protocol demonstrating how to respond to the patient using the three phases to maximize responses to hypnotic suggestions is presented. PMID:27586048

  8. Terahertz spectrum analysis of leather at room temperature

    NASA Astrophysics Data System (ADS)

    Li, Jiusheng; Yao, Jianquan; Li, Jianrui

    2008-12-01

    Over the past ten years, electromagnetic terahertz (THz) frequencies region from 100 GHz to 10 THz (or wavelengths of 30 μm ~3 mm) have received extensive attention and investigation. Terahertz wave detection enables direct calculations of both the imaginary and the real parts of the refractive index without using the Kramers-Kronig relations. There are many potential applications such as radio astronomy, atmospheric studies, remote sensing, and plasma diagnostics. Shoes, neckties and sofa, etc are mainly made of skin of animal, imitated skin and artificial leather. It has important practical value to component analysis and quality assessment by measuring absorption, refractive index, and other optical parameters. In this paper, the spectral characteristics of sheepskin, imitated sheepskin and artificial leather have been measured with terahertz time-domain spectroscopy (THz-TDS) in the range of 0.1~2.0THz. The results show that there have not absorption peak in the absorption spectrum of the sheepskin. However, it is found that there are three absorption peaks in the absorption spectrum of the artificial leather at the frequency of 1.13THz, 1.21THz, and 1.36THz, respectively. The potential application of the leather in THz frequency region is also discussed.

  9. Suggested Minimum Cataloging Standards for Arizona.

    ERIC Educational Resources Information Center

    Scott, Sharon

    1979-01-01

    Notes problems with cataloging library materials in the small and medium sized public library and suggests interpretations of the Anglo-American cataloging rules, with recommendations for their adaptation to smaller libraries. (CWM)

  10. Social suggestibility to central and peripheral misinformation.

    PubMed

    Dalton, Andrea L; Daneman, Meredyth

    2006-05-01

    This study used a laboratory-based paradigm to investigate social influences on participants' susceptibility to misleading suggestions. Participants viewed a video clip of an action sequence with one or more peers, and then were required to discuss the event with the co-witness or with the group of co-witnesses. During the discussion a confederate, posing as a peer, presented misinformation about central and peripheral features of the co-witnessed event. Results indicated that participants were more susceptible to misleading suggestions during one-on-one discussions than during group discussions. In addition, participants were susceptible to misleading suggestions about central features of the witnessed event, although to a lesser extent than they were susceptible to misleading suggestions about peripheral features. PMID:16766450

  11. No Statins Before Heart Surgery, Study Suggests

    MedlinePlus

    ... harm, a new study suggests. In that setting, Crestor (rosuvastatin) did not prevent either the abnormal heart rhythm ... who were having elective heart surgery to take Crestor or a placebo before surgery. The researchers found ...

  12. Electronic Reference Services: Some Suggested Guidelines.

    ERIC Educational Resources Information Center

    Sloan, Bernie

    1998-01-01

    Suggests guidelines to help libraries formalize their electronic reference services. Covers the following issues: administration/management (library division/department, library administration, campus administration, academic departments); services; primary clientele; personnel; infrastructure/facilities; finances; and evaluation. (AEF)

  13. Economics of spectrum allocation

    NASA Astrophysics Data System (ADS)

    Melody, W. H.

    The effective and efficient allocation and use of the spectrum can be ensured only by a set of sharing rules that will reflect the interests, values, and power of all affected parties. What is now happening is that the new interests and different values of the developing countries are pressing to change the international sharing rules established by a small group of high-technology nations. It is noted that the latter have established a massive telecommunications infrastructure on the basis of inherited sharing rules that reflect only their interests and a much simplified scarcity problem. Once long-term goals and underlying principles of allocation are established, communication technologies and markets can be directed, through a series of adjustment policies, to achieve them. A crucial first step in the creation of an international information environment in which 'free' flows will be balanced flows is the establishment of a balanced and equitable set of sharing rules for the radio spectrum.

  14. Spread spectrum image steganography.

    PubMed

    Marvel, L M; Boncelet, C R; Retter, C T

    1999-01-01

    In this paper, we present a new method of digital steganography, entitled spread spectrum image steganography (SSIS). Steganography, which means "covered writing" in Greek, is the science of communicating in a hidden manner. Following a discussion of steganographic communication theory and review of existing techniques, the new method, SSIS, is introduced. This system hides and recovers a message of substantial length within digital imagery while maintaining the original image size and dynamic range. The hidden message can be recovered using appropriate keys without any knowledge of the original image. Image restoration, error-control coding, and techniques similar to spread spectrum are described, and the performance of the system is illustrated. A message embedded by this method can be in the form of text, imagery, or any other digital signal. Applications for such a data-hiding scheme include in-band captioning, covert communication, image tamperproofing, authentication, embedded control, and revision tracking. PMID:18267522

  15. Sensors across the Spectrum

    NASA Astrophysics Data System (ADS)

    Neese, Christopher F.; De Lucia, Frank C.; Medvedev, Ivan R.

    2011-06-01

    A resurgence of interest in spectroscopic sensors has been fueled by increases in performance made possible by technological advancements and applications in medicine, environmental monitoring, and national security. Often this research is technology driven, without enough consideration of the spectroscopic signatures available to be probed. We will compare several current spectroscopic sensors across the electromagnetic spectrum, with an eye towards the fundamental spectroscopic considerations important at each wavelength.

  16. The marine diversity spectrum.

    PubMed

    Reuman, Daniel C; Gislason, Henrik; Barnes, Carolyn; Mélin, Frédéric; Jennings, Simon

    2014-07-01

    Distributions of species body sizes within a taxonomic group, for example, mammals, are widely studied and important because they help illuminate the evolutionary processes that produced these distributions. Distributions of the sizes of species within an assemblage delineated by geography instead of taxonomy (all the species in a region regardless of clade) are much less studied but are equally important and will illuminate a different set of ecological and evolutionary processes. We develop and test a mechanistic model of how diversity varies with body mass in marine ecosystems. The model predicts the form of the 'diversity spectrum', which quantifies the distribution of species' asymptotic body masses, is a species analogue of the classic size spectrum of individuals, and which we have found to be a new and widely applicable description of diversity patterns. The marine diversity spectrum is predicted to be approximately linear across an asymptotic mass range spanning seven orders of magnitude. Slope -0.5 is predicted for the global marine diversity spectrum for all combined pelagic zones of continental shelf seas, and slopes for large regions are predicted to lie between -0.5 and -0.1. Slopes of -0.5 and -0.1 represent markedly different communities: a slope of -0.5 depicts a 10-fold reduction in diversity for every 100-fold increase in asymptotic mass; a slope of -0.1 depicts a 1.6-fold reduction. Steeper slopes are predicted for larger or colder regions, meaning fewer large species per small species for such regions. Predictions were largely validated by a global empirical analysis. Results explain for the first time a new and widespread phenomenon of biodiversity. Results have implications for estimating numbers of species of small asymptotic mass, where taxonomic inventories are far from complete. Results show that the relationship between diversity and body mass can be explained from the dependence of predation behaviour, dispersal, and life history on

  17. Credible suggestions affect false autobiographical beliefs.

    PubMed

    Scoboria, Alan; Wysman, Lauren; Otgaar, Henry

    2012-07-01

    False memory implantation studies are characterised by suggestions indicating that specific unremembered events occurred, attributing suggested events to a knowledgeable source (e.g., parents), and including true events that provide evidence that this source was consulted. These characteristics create a particular retrieval context that influences how individuals come to believe that false events occurred. Two studies used a variant of implantation methods to vary the proportion of events attributed to parents and the presence of true events within the suggestion. In Study 1 participants received six false events, and were told that all or some events came from parents. Participants told that all of the events came from parents formed more and stronger false beliefs. In Study 2 participants also received two true events, and a third group was told that half of the events came from their parents. Participants given the specific ratio ("half") endorsed more false beliefs, and beliefs between the other groups no longer differed. Across both studies participants told that some events came from parents reported stronger memory phenomenology. The effect of suggestions on false beliefs in implantation studies depends partly on the credibility of suggestions derived from providing information about the source of suggested events. PMID:22537029

  18. Multifrequency VLBI Observations of the Broad Absorption Line Quasar J1020+4320: Recently Restarted Jet Activity?

    NASA Astrophysics Data System (ADS)

    Doi, Akihiro; Murata, Yasuhiro; Mochizuki, Nanako; Takeuchi, Hiroshi; Asada, Keiichi; Hayashi, Takayuki J.; Nagai, Hiroshi; Shibata, Katsunori M.; Oyama, Tomoaki; Jike, Takaaki; Fujisawa, Kenta; Sugiyama, Koichiro; Ogawa, Hideo; Kimura, Kimihiro; Honma, Mareki; Kobayashi, Hideyuki; Koyama, Shoko

    2013-06-01

    This paper reports on very-long-baseline interferometry observations of the radio-loud broad absorption line (BAL) quasar J1020+4320 at 1.7, 2.3, 6.7, and 8.4 GHz using the Japanese VLBI network (JVN) and European VLBI network (EVN). The radio morphology is compact with a size of ˜10 pc. The convex radio spectrum has been stable over the last decade; an observed peak frequency of 3.2 GHz is equivalent to 9.5 GHz in the rest frame, suggesting an age on the order of ˜100 years as a radio source, according to an observed correlation between the linear size and the peak frequency of compact steep spectrum (CSS) and giga-hertz peaked spectrum (GPS) radio sources. A low-frequency radio excess suggests a relic of past jet activity. J1020+4320 may be one of the quasars with recurrent and short-lived jet activity during a BAL-outflowing phase.

  19. Cloud geometry effects on atmospheric solar absorption

    SciTech Connect

    Fu, Q.; Cribb, M.C.; Barker, H.W.; Krueger, S.K.; Grossman, A.

    2000-04-15

    A 3D broadband solar radiative transfer scheme is formulated by integrating a Monte Carlo photon transport algorithm with the Fu-Liou radiation model. It is applied to fields of tropical mesoscale convective clouds and subtropical marine boundary layer clouds that were generated by a 2D cloud-resolving model. The effects of cloud geometry on the radiative energy budget are examined by comparing the full-resolution Monte Carlo results with those from the independent column approximation (ICA) that applies the plane-parallel radiation model to each column. For the tropical convective cloud system, it is found that cloud geometry effects always enhance atmospheric solar absorption regardless of solar zenith angle. In a large horizontal domain (512 km), differences in domain-averaged atmospheric absorption between the Monte Carlo and the ICA are less than 4 W m{sup {minus}2} in the daytime. However, for a smaller domain (e.g., 75 km) containing a cluster of deep convective towers, domain-averaged absorption can be enhanced by more than 20 W m{sup {minus}2}. For a subtropical marine boundary layer cloud system during the stratus-to-cumulus transition, calculations show that the ICA works very well for domain-averaged fluxes of the stratocumulus cloud fields even for a very small domain (4.8 km). For the trade cumulus cloud field, the effects of cloud sides and horizontal transport of photons become more significant. Calculations have also been made for both cloud systems including black carbon aerosol and a water vapor continuum. It is found that cloud geometry produces no discernible effects on the absorption enhancement due to the black carbon aerosol and water vapor continuum. The current study indicates that the atmospheric absorption enhancement due to cloud-related 3D photon transport is small. This enhancement could not explain the excess absorption suggested by recent studies.

  20. Sulfuric acid cloud interpretation of the infrared spectrum of Venus

    NASA Technical Reports Server (NTRS)

    Martonchik, J. V.

    1974-01-01

    Sulfuric acid single-cloud models are compared with the Venus spectrum in the 8-14 micron region. The results indicate that a cloud composed of a 75 percent H2SO4 solution and with a particle density of 100 per cu cm is in good agreement with observations. In addition to explaining the 11.2 micron absorption, this model also predicts an absorption feature at 16.7 microns which should be detectable if the observation is made from an aircraft.

  1. Visible Spectrum Incandescent Selective Emitter

    SciTech Connect

    Sonsight Inc.

    2004-04-30

    The purpose of the work performed was to demonstrate the feasibility of a novel bi-layer selective emitter. Selective emitters are incandescent radiant bodies with emissivities that are substantially larger in a selected part of the radiation spectrum, thereby significantly shifting their radiated spectral distribution from that of a blackbody radiating at the same temperature. The major research objectives involved answering the following questions: (1) What maximum VIS/NIR radiant power and emissivity ratios can be attained at 2650 K? (2) What is the observed emitter body life and how does its performance vary with time? (3) What are the design tradeoffs for a dual heating approach in which both an internally mounted heating coil and electrical resistance self-heating are used? (4) What are the quantitative improvements to be had from utilizing a bi-layer emitter body with a low emissivity inner layer and a partially transmissive outer layer? Two approaches to obtaining selective emissivity were investigated. The first was to utilize large optical scattering within an emitter material with a spectral optical absorption that is much greater within the visible spectrum than that within the NIR. With this approach, an optically thick emitter can radiate almost as if optically thin because essentially, scattering limits the distance below the surface from which significant amounts of internally generated radiation can emerge. The performance of thin emitters was also investigated (for optically thin emitters, spectral emissivity is proportional to spectral absorptivity). These emitters were fabricated from thin mono-layer emitter rods as well as from bi-layer rods with a thin emitter layer mounted on a substrate core. With an initially estimated energy efficiency of almost three times that of standard incandescent bulbs, a number of energy, economic and environmental benefits such as less energy use and cost, reduced CO{sub 2} emissions, and no mercury contamination

  2. Differential optoacoustic absorption detector

    NASA Technical Reports Server (NTRS)

    Shumate, M. S. (Inventor)

    1978-01-01

    A differential optoacoustic absorption detector employed two tapered cells in tandem or in parallel. When operated in tandem, two mirrors were used at one end remote from the source of the beam of light directed into one cell back through the other, and a lens to focus the light beam into the one cell at a principal focus half way between the reflecting mirror. Each cell was tapered to conform to the shape of the beam so that the volume of one was the same as for the other, and the volume of each received maximum illumination. The axes of the cells were placed as close to each other as possible in order to connect a differential pressure detector to the cells with connecting passages of minimum length. An alternative arrangement employed a beam splitter and two lenses to operate the cells in parallel.

  3. Cloud absorption radiometer

    NASA Technical Reports Server (NTRS)

    Strange, M. G.

    1988-01-01

    The Cloud Absorption Radiometer (CAR) was developed to measure spectrally how light is scattered by clouds and to determine the single scattering albedo, important to meteorology and climate studies, with unprecedented accuracy. This measurement is based on ratios of downwelling to upwelling radiation within clouds, and so is not strongly dependent upon absolute radiometric calibration of the instrument. The CAR has a 5-inch aperture and 1 degree IFOV, and spatially scans in a plane orthogonal to the flight vector from the zenith to nadir at 1.7 revolutions per second. Incoming light is measured in 13 spectral bands, using silicon, germanium, and indium-antimonide detectors. Data from each channel is digitally recorded in flight with 10-bit (0.1 percent) resolution. The instrument incorporates several novel features. These features are briefly detailed.

  4. Analyzing Water's Optical Absorption

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A cooperative agreement between World Precision Instruments (WPI), Inc., and Stennis Space Center has led the UltraPath(TM) device, which provides a more efficient method for analyzing the optical absorption of water samples at sea. UltraPath is a unique, high-performance absorbance spectrophotometer with user-selectable light path lengths. It is an ideal tool for any study requiring precise and highly sensitive spectroscopic determination of analytes, either in the laboratory or the field. As a low-cost, rugged, and portable system capable of high- sensitivity measurements in widely divergent waters, UltraPath will help scientists examine the role that coastal ocean environments play in the global carbon cycle. UltraPath(TM) is a trademark of World Precision Instruments, Inc. LWCC(TM) is a trademark of World Precision Instruments, Inc.

  5. Twin-peaks absorption spectra of excess electron in ionic liquids

    NASA Astrophysics Data System (ADS)

    Musat, Raluca M.; Kondoh, Takafumi; Yoshida, Yoichi; Takahashi, Kenji

    2014-07-01

    The solvated electron in room temperature ionic liquids (RTILs) has been the subject of several investigations and several reports exist on its nature and absorption spectrum. These studies concluded that the solvated electron exhibits an absorption spectrum peaking in the 1000-1400 nm region; a second absorption band peaking in the UV region has been assigned to the hole or dication radicals simultaneously formed in the system. Here we report on the fate of the excess electron in the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, P14+/NTf2- using nanosecond pulse radiolysis. Scavenging experiments allowed us to record and disentangle the complex spectrum measured in P14+/NTf2-. We identified a bi-component absorption spectrum, due to the solvated electron, the absorption maxima located at 1080 nm and around 300 nm, as predicted by previous ab-initio molecular dynamics simulations for the dry excess electron. We also measured the spectra using different ionic liquids and confirmed the same feature of two absorption peaks. The present results have important implications for the characterization of solvated electrons in ionic liquids and better understanding of their structure and reactivity.

  6. Two-photon absorption in Hg 2Cl 2 crystals

    NASA Astrophysics Data System (ADS)

    Pelant, I.; Ambrož, M.; Hála, J.; Kohlová, V.; Barta, Č.

    1985-01-01

    Violet luminescence (396 nm) of Hg 2Cl 2 single crystals was observed under excitation of green light (∼ 500 nm) of a pulsed dye laser at liquid helium temperature. The effect is interpreted as due to the two-photon absorption process. The two-photon excitation spectrum of the luminescence was measured in the wavelength range 475-530 nm. Possible mechanisms of the two-photon transition are outlined.

  7. Electron paramagnetic resonance and optical absorption spectral studies on chalcocite

    NASA Astrophysics Data System (ADS)

    Reddy, S. Lakshmi; Fayazuddin, Md.; Frost, Ray L.; Endo, Tamio

    2007-11-01

    A chalcocite mineral sample of Shaha, Congo is used in the present study. An electron paramagnetic resonance (EPR) study on powdered sample confirms the presence of Mn(II), Fe(III) and Cu(II). Optical absorption spectrum indicates that Fe(III) impurity is present in octahedral structure whereas Cu(II) is present in rhombically distorted octahedral environment. Mid-infrared results are due to water and sulphate fundamentals.

  8. Electron paramagnetic resonance and optical absorption spectral studies on chalcocite.

    PubMed

    Reddy, S Lakshmi; Fayazuddin, Md; Frost, Ray L; Endo, Tamio

    2007-11-01

    A chalcocite mineral sample of Shaha, Congo is used in the present study. An electron paramagnetic resonance (EPR) study on powdered sample confirms the presence of Mn(II), Fe(III) and Cu(II). Optical absorption spectrum indicates that Fe(III) impurity is present in octahedral structure whereas Cu(II) is present in rhombically distorted octahedral environment. Mid-infrared results are due to water and sulphate fundamentals. PMID:17324611

  9. Fractionation of Social Brain Circuits in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Gotts, Stephen J.; Simmons, W. Kyle; Milbury, Lydia A.; Wallace, Gregory L.; Cox, Robert W.; Martin, Alex

    2012-01-01

    Autism spectrum disorders are developmental disorders characterized by impairments in social and communication abilities and repetitive behaviours. Converging neuroscientific evidence has suggested that the neuropathology of autism spectrum disorders is widely distributed, involving impaired connectivity throughout the brain. Here, we evaluate the…

  10. Psychopharmacology of Autism Spectrum Disorders: A Selective Review

    ERIC Educational Resources Information Center

    Mohiuddin, Sarah; Ghaziuddin, Mohammad

    2013-01-01

    While there is no cure for autism spectrum disorder, psychopharmacologic agents are often used with behavioral and educational approaches to treat its comorbid symptoms of hyperactivity, irritability, and aggression. Studies suggest that at least 50% of persons with autism spectrum disorder receive psychotropic medications during their life span.…

  11. Measuring Children's Suggestibility in Forensic Interviews.

    PubMed

    Volpini, Laura; Melis, Manuela; Petralia, Stefania; Rosenberg, Melina D

    2016-01-01

    According to the scientific literature, childrens' cognitive development is not complete until adolescence. Therefore, the problems inherent in children serving as witnesses are crucial. In preschool-aged children, false memories may be identified because of misinformation and insight bias. Additionally, they are susceptible of suggestions. The aim of this study was to verify the levels of suggestibility in children between three and 5 years of age. Ninety-two children were examined (44 male, 48 female; M = 4.5 years, SD = 9.62). We used the correlation coefficient (Pearson's r) and the averages variance by SPSS statistical program. The results concluded that: younger children are almost always more susceptible to suggestibility. The dimension of immediate recall was negatively correlates with that of total suggestibility (r = -0.357 p < 0.001). Social compliance and source monitoring errors contribute to patterns of suggestibility, because older children shift their answers more often (r = 0.394 p < 0.001). Younger children change their answers more times (r = -0.395 p < 0.001). PMID:27404406

  12. Device for frequency modulation of a laser output spectrum

    DOEpatents

    Beene, James R.; Bemis, Jr., Curtis E.

    1986-01-01

    A device is provided for fast frequency modulating the output spectrum of multimode lasers and single frequency lasers that are not actively stabilized. A piezoelectric transducer attached to a laser cavity mirror is driven in an unconventional manner to excite resonance vibration of the transducer to rapidly, cyclicly change the laser cavity length. The result is a cyclic sweeping of the output wavelength sufficient to fill the gaps in the laser output frequency spectrum. When such a laser is used to excite atoms or molecules, complete absorption line coverage is made possible.

  13. Device for frequency modulation of a laser output spectrum

    DOEpatents

    Beene, J.R.; Bemis, C.E. Jr.

    1984-07-17

    A device is provided for fast frequency modulating the output spectrum of multimode lasers and single frequency lasers that are not actively stabilized. A piezoelectric transducer attached to a laser cavity mirror is driven in an unconventional manner to excite resonance vibration of the tranducer to rapidly, cyclicly change the laser cavity length. The result is a cyclic sweeping of the output wavelength sufficient to fill the gaps in the laser output frequency spectrum. When a laser is used to excite atoms or molecules, complete absorption line coverage is made possible.

  14. The microwave spectrum of the AlO radical

    NASA Technical Reports Server (NTRS)

    Yamada, Chikashi; Fujitake, Masaharu; Hirota, Eizi; Cohen, Edward A.

    1990-01-01

    The rotational spectrum of the aluminum monoxide radical in the ground electronic state X 2Sigma(+) was observed in the millimeter- and submillimeter-wave region. Aluminum monoxide radicals were generated directly in a flow reactor absorption cell by the reaction of N2O with aluminum vaporized from a high-temperature crucible. The observed spectrum was analyzed to yield molecular constants including the rotational constant, centrifugal distortion constant, spin-rotation interaction constant, magnetic hyperfine interaction constants, and nuclear quadrupole coupling constant.

  15. The free jet microwave spectrum of 2-phenylethylamine-water.

    PubMed

    Melandri, Sonia; Maris, Assimo; Giuliano, Barbara M; Favero, Laura B; Caminati, Walther

    2010-09-21

    We observed the rotational spectrum of the 1:1 molecular adduct between 2-phenylethylamine and water (normal and H(2)(18)O species) by free jet absorption microwave spectroscopy in the frequency region 60-78 GHz. The dominant spectrum belongs to the structure where the PEA moiety is in the most stable gauche conformation and the water molecule is hydrogen bound to the nitrogen lone pair. The orientation of the water molecule is such that the oxygen atom is almost equidistant (ca. 2.5 A) from the closest methylenic and aromatic hydrogen atoms. PMID:20601990

  16. Theoretical antideuteron-nucleus absorptive cross sections

    NASA Technical Reports Server (NTRS)

    Buck, W. W.; Norbury, J. W.; Townsend, L. W.; Wilson, J. W.

    1993-01-01

    Antideuteron-nucleus absorptive cross sections for intermediate to high energies are calculated using an ion-ion optical model. Good agreement with experiment (within 15 percent) is obtained in this same model for (bar p)-nucleus cross sections at laboratory energies up to 15 GeV. We describe a technique for estimating antinucleus-nucleus cross sections from NN data and suggest that further cosmic ray studies to search for antideuterons and other antinuclei be undertaken.

  17. Extreme Variability in a Broad Absorption Line Quasar

    NASA Astrophysics Data System (ADS)

    Stern, Daniel; Graham, Matthew; Arav, Nahum; Djorgovski, Stanislav G.; Chamberlain, Carter; Barth, Aaron J.; Donalek, Ciro; Drake, Andrew J.; Glikman, Eilat; Jun, Hyunsung David; Mahabal, Ashish A.; Steidel, Charles C.

    2016-01-01

    We report on extreme spectral variability seen in a broad absorption line quasar over the past decade, initially identified from the Catalina Real-time Transient Survey (CRTS). Photometrically, the source had a visual magnitude of V = 17.3 between 2002 and 2008. Then, over the following 5 years, the source slowly brightened by approximately one magnitude, to V = 16.2. A combination of archival and newly acquired spectra reveal the source to be an iron low-ionization broad absorption line (Fe-LoBAL) quasar with extreme changes in its absorption spectrum. Some absorption features completely disappear over the 9 years of optical spectra, while other features remain essentially unchanged. Absorption systems separated by several 1000 km/s in velocity show coordinated changes in the depths of their troughs, correlated with the flux changes. Therefore, we interpret the variability in the absorption troughs to be due to changes in photoionization, rather than due to motion of material into our line of sight. This source highlights the sort of rare transition objects that astronomy will now be finding through dedicated time domain surveys.

  18. Percutaneous absorption in preterm infants.

    PubMed

    West, D P; Halket, J M; Harvey, D R; Hadgraft, J; Solomon, L M; Harper, J I

    1987-11-01

    The skin of preterm infants varies considerably in its level of maturity. To understand skin absorption in premature infants better, we report a technique for the assessment of percutaneous absorption at various gestational and postnatal ages using stable, isotope-labeled (13C6) benzoic acid. Our results indicate that in the preterm infant, this method detects enhanced skin absorption in the first postnatal days, which declines over three weeks to that expected of a full-term infant. This approach also indicates an inverse relationship between gestational age and skin absorption, as well as postnatal age and skin absorption. The reported technique is a safe and noninvasive method using a model skin penetrant for the study of percutaneous absorption in preterm infants from which basic data may be derived to add to our understanding of skin barrier function. PMID:3422856

  19. Fetal Alcohol Spectrum Disorders (FASDs)

    MedlinePlus

    ... FASD Cancel Submit Search The CDC Fetal Alcohol Spectrum Disorders (FASDs) Note: Javascript is disabled or is ... Recommend on Facebook Tweet Share Compartir Fetal alcohol spectrum disorders (FASDs) are a group of conditions that ...

  20. UNSHIFTED METASTABLE He I* MINI-BROAD ABSORPTION LINE SYSTEM IN THE NARROW-LINE TYPE 1 QUASAR SDSS J080248.18+551328.9

    SciTech Connect

    Ji, Tuo; Zhou, Hongyan; Jiang, Peng; Wang, Tinggui; Wang, Huiyuan; Liu, Wenjuan; Yang, Chenwei; Ge, Jian; Hamann, Fred; Komossa, S.; Yuan, Weimin; Zuther, Jens; Lu, Honglin; Zuo, Wenwen

    2015-02-10

    We report the identification of an unusual absorption-line system in the quasar SDSS J080248.18+551328.9 and present a detailed study of the system, incorporating follow-up optical and near-IR spectroscopy. A few tens of absorption lines are detected, including He I*, Fe II*, and Ni II*, which arise from metastable or excited levels, as well as resonant lines in Mg I, Mg II, Fe II, Mn II, and Ca II. All of the isolated absorption lines show the same profile of width Δv ∼ 1500 km s{sup –1} centered at a common redshift as that of the quasar emission lines, such as [O II], [S II], and hydrogen Paschen and Balmer series. With narrow Balmer lines, strong optical Fe II multiplets, and weak [O III] doublets, its emission-line spectrum is typical for that of a narrow-line Seyfert 1 galaxy (NLS1). We have derived reliable measurements of the gas-phase column densities of the absorbing ions/levels. Photoionization modeling indicates that the absorber has a density of n {sub H} ∼ (1.0-2.5) × 10{sup 5} cm{sup –3} and a column density of N {sub H} ∼ (1.0-3.2) × 10{sup 21} cm{sup –2} and is located at R ∼100-250 pc from the central supermassive black hole. The location of the absorber, the symmetric profile of the absorption lines, and the coincidence of the absorption- and emission-line centroid jointly suggest that the absorption gas originates from the host galaxy and is plausibly accelerated by stellar processes, such as stellar winds and/or supernova explosions. The implications for the detection of such a peculiar absorption-line system in an NLS1 are discussed in the context of coevolution between supermassive black hole growth and host galaxy buildup.