WorldWideScience

Sample records for 3d-3d emission spectra

  1. Simultaneous observation of low temperature 4f-4f and 3d-3d emission spectra in a series of Cr(III)(ox)Ln(III) assembly

    CERN Document Server

    Subhan, M A; Suzuki, T; Choi, J H; Kaizaki, S

    2003-01-01

    We report here the low temperature emission spectra in the heterometal dinuclear 3d-4f assembled molecular system [(acac) sub 2 Cr sup I sup I sup I (mu-ox)Ln sup I sup I sup I (HBpz sub 3) sub 2] (Cr(ox)Ln:acac sup - =acetylacetonate, ox sup 2 sup - =oxalate, HBpz sub 3 sup - =hydrotris(pyrazol-1-yl)borate; Ln=La, Nd, Ho, Er , Tm and Yb) in comparison with those of Na[Cr(acac) sub 2 (ox)] and [(HBpz sub 3) sub 2 Ln(mu-ox)Ln(HBpz sub 3) sub 2](Ln=Nd and Er). From 10 to 150 K the Cr(ox)Ln complexes show a broad emission band around 800 nm from the sup 2 E state of Cr(III) moiety. At room temperature no sup 2 E- sup 4 A sub 2 emission was observed in the Cr(ox)Ln except for the La and Lu complexes. On warming from 10 to 300 K rapid quenching of the sup 2 E- sup 4 A sub 2 emission of Cr(III) is suggested to result from the energy transfer from Cr to Ln in the Cr(ox)Ln. The excitation spectra and the life-time were also measured with monitoring the 4f-4f emission peaks of the Cr(ox)Yb complex.

  2. Holography of 3d-3d correspondence at Large N

    OpenAIRE

    Gang, Dongmin; Kim, Nakwoo; Lee, Sangmin

    2014-01-01

    We study the physics of multiple M5-branes compactified on a hyperbolic 3-manifold. On the one hand, it leads to the 3d-3d correspondence which maps an N = 2 $$ \\mathcal{N}=2 $$ superconformal field theory to a pure Chern-Simons theory on the 3-manifold. On the other hand, it leads to a warped AdS 4 geometry in M-theory holographically dual to the superconformal field theory. Combining the holographic duality and the 3d-3d correspondence, we propose a conjecture for the large N limit of the p...

  3. Holography of 3d-3d correspondence at large N

    Energy Technology Data Exchange (ETDEWEB)

    Gang, Dongmin [School of Physics, Korea Institute for Advanced Study,85 Hoegiro, Dongdaemun-gu, Seoul, 130-722 (Korea, Republic of); Kim, Nakwoo [Department of Physics and Research Institute of Basic Science, Kyung Hee University,26 Kyungheedaero, Dongdaemun-gu, Seoul, 130-701 (Korea, Republic of); Lee, Sangmin [School of Physics, Korea Institute for Advanced Study,85 Hoegiro, Dongdaemun-gu, Seoul, 130-722 (Korea, Republic of); Center for Theoretical Physics, Department of Physics and Astronomy, College of Liberal Studies,Seoul National University, 1 Gwanakro, Gwanak-gu, Seoul, 151-742 (Korea, Republic of)

    2015-04-20

    We study the physics of multiple M5-branes compactified on a hyperbolic 3-manifold. On the one hand, it leads to the 3d-3d correspondence which maps an N=2 superconformal field theory to a pure Chern-Simons theory on the 3-manifold. On the other hand, it leads to a warped AdS{sub 4} geometry in M-theory holographically dual to the superconformal field theory. Combining the holographic duality and the 3d-3d correspondence, we propose a conjecture for the large N limit of the perturbative free energy of a Chern-Simons theory on hyperbolic 3-manifold. The conjecture claims that the tree, one-loop and two-loop terms all share the same N{sup 3} scaling behavior and are proportional to the volume of the 3-manifold, while the three-loop and higher terms are suppressed at large N. Under mild assumptions, we prove the tree and one-loop parts of the conjecture. For the two-loop part, we test the conjecture numerically in a number of examples and find precise agreement. We also confirm the suppression of higher loop terms in a few examples.

  4. Aspects of defects in 3d-3d correspondence

    Energy Technology Data Exchange (ETDEWEB)

    Gang, Dongmin [Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo,Chiba 277-8583 (Japan); Kim, Nakwoo [Department of Physics and Research Institute of Basic Science, Kyung Hee University,Seoul 02447 (Korea, Republic of); School of Physics, Korea Institute for Advanced Study,Seoul 02455 (Korea, Republic of); Romo, Mauricio; Yamazaki, Masahito [Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo,Chiba 277-8583 (Japan); School of Natural Sciences, Institute for Advanced Study,Princeton, NJ 08540 (United States)

    2016-10-12

    In this paper we study supersymmetric co-dimension 2 and 4 defects in the compactification of the 6d (2,0) theory of type A{sub N−1} on a 3-manifold M. The so-called 3d-3d correspondence is a relation between complexified Chern-Simons theory (with gauge group SL(N,ℂ)) on M and a 3d N=2 theory T{sub N}[M]. We study this correspondence in the presence of supersymmetric defects, which are knots/links inside the 3-manifold. Our study employs a number of different methods: state-integral models for complex Chern-Simons theory, cluster algebra techniques, domain wall theory T[SU(N)], 5d N=2 SYM, and also supergravity analysis through holography. These methods are complementary and we find agreement between them. In some cases the results lead to highly non-trivial predictions on the partition function. Our discussion includes a general expression for the cluster partition function, which can be used to compute in the presence of maximal and certain class of non-maximal punctures when N>2. We also highlight the non-Abelian description of the 3d N=2T{sub N}[M] theory with defect included, when such a description is available. This paper is a companion to our shorter paper http://dx.doi.org/10.1088/1751-8113/49/30/30LT02, which summarizes our main results.

  5. Aspects of defects in 3d-3d correspondence

    Science.gov (United States)

    Gang, Dongmin; Kim, Nakwoo; Romo, Mauricio; Yamazaki, Masahito

    2016-10-01

    In this paper we study supersymmetric co-dimension 2 and 4 defects in the compactification of the 6d (2, 0) theory of type A N -1 on a 3-manifold M . The so-called 3d-3d correspondence is a relation between complexified Chern-Simons theory (with gauge group SL(N,C) ) on M and a 3d N=2 theory T N [ M ]. We study this correspondence in the presence of supersymmetric defects, which are knots/links inside the 3-manifold. Our study employs a number of different methods: state-integral models for complex Chern-Simons theory, cluster algebra techniques, domain wall theory T [SU( N )], 5d N=2 SYM, and also supergravity analysis through holography. These methods are complementary and we find agreement between them. In some cases the results lead to highly non-trivial predictions on the partition function. Our discussion includes a general expression for the cluster partition function, which can be used to compute in the presence of maximal and certain class of non-maximal punctures when N > 2. We also highlight the non-Abelian description of the 3d N=2 T N [ M ] theory with defect included, when such a description is available. This paper is a companion to our shorter paper [1], which summarizes our main results.

  6. Superconformal index and 3d-3d correspondence for mapping cylinder/torus

    Energy Technology Data Exchange (ETDEWEB)

    Gang, Dongmin; Koh, Eunkyung [School of Physics, Korea Institute for Advanced Study,85 Hoegiro, Seoul 130-722 (Korea, Republic of); Lee, Sangmin [Center for Theoretical Physics, Seoul National University,1 Gwanak-ro, Seoul 151-747 (Korea, Republic of); Department of Physics and Astronomy, Seoul National University,1 Gwanak-ro, Seoul 151-747 (Korea, Republic of); College of Liberal Studies, Seoul National University,1 Gwanak-ro, Seoul 151-742 (Korea, Republic of); Park, Jaemo [Department of Physics, POSTECH,77 Cheongam-Ro, Pohang 790-784 (Korea, Republic of); Postech Center for Theoretical Physics (PCTP), Postech,77 Cheongam-Ro, Pohang 790-784 (Korea, Republic of)

    2014-01-15

    We probe the 3d-3d correspondence for mapping cylinder/torus using the superconformal index. We focus on the case when the fiber is a once-punctured torus (Σ{sub 1,1}). The corresponding 3d field theories can be realized using duality domain wall theories in 4d N=2{sup ∗} theory. We show that the superconformal indices of the 3d theories are the SL(2,ℂ) Chern-Simons partition function on the mapping cylinder/torus. For the mapping torus, we also consider another realization of the corresponding 3d theory associated with ideal triangulation. The equality between the indices from the two descriptions for the mapping torus theory is reduced to a simple basis change of the Hilbert space for the SL(2,ℂ) Chern-Simons theory on ℝ×Σ{sub 1,1}.

  7. A View to the Future: A Novel Approach for 3D-3D Superimposition and Quantification of Differences for Identification from Next-Generation Video Surveillance Systems.

    Science.gov (United States)

    Gibelli, Daniele; De Angelis, Danilo; Poppa, Pasquale; Sforza, Chiarella; Cattaneo, Cristina

    2017-03-01

    Techniques of 2D-3D superimposition are widely used in cases of personal identification from video surveillance systems. However, the progressive improvement of 3D image acquisition technology will enable operators to perform also 3D-3D facial superimposition. This study aims at analyzing the possible applications of 3D-3D superimposition to personal identification, although from a theoretical point of view. Twenty subjects underwent a facial 3D scan by stereophotogrammetry twice at different time periods. Scans were superimposed two by two according to nine landmarks, and root-mean-square (RMS) value of point-to-point distances was calculated. When the two superimposed models belonged to the same individual, RMS value was 2.10 mm, while it was 4.47 mm in mismatches with a statistically significant difference (p forensic practice. © 2016 American Academy of Forensic Sciences.

  8. A neural network based 3D/3D image registration quality evaluator for the head-and-neck patient setup in the absence of a ground truth

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jian; Murphy, Martin J. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)

    2010-11-15

    Purpose: To develop a neural network based registration quality evaluator (RQE) that can identify unsuccessful 3D/3D image registrations for the head-and-neck patient setup in radiotherapy. Methods: A two-layer feed-forward neural network was used as a RQE to classify 3D/3D rigid registration solutions as successful or unsuccessful based on the features of the similarity surface near the point-of-solution. The supervised training and test data sets were generated by rigidly registering daily cone-beam CTs to the treatment planning fan-beam CTs of six patients with head-and-neck tumors. Two different similarity metrics (mutual information and mean-squared intensity difference) and two different types of image content (entire image versus bony landmarks) were used. The best solution for each registration pair was selected from 50 optimizing attempts that differed only by the initial transformation parameters. The distance from each individual solution to the best solution in the normalized parametrical space was compared to a user-defined error threshold to determine whether that solution was successful or not. The supervised training was then used to train the RQE. The performance of the RQE was evaluated using the test data set that consisted of registration results that were not used in training. Results: The RQE constructed using the mutual information had very good performance when tested using the test data sets, yielding the sensitivity, the specificity, the positive predictive value, and the negative predictive value in the ranges of 0.960-1.000, 0.993-1.000, 0.983-1.000, and 0.909-1.000, respectively. Adding a RQE into a conventional 3D/3D image registration system incurs only about 10%-20% increase of the overall processing time. Conclusions: The authors' patient study has demonstrated very good performance of the proposed RQE when used with the mutual information in identifying unsuccessful 3D/3D registrations for daily patient setup. The classifier

  9. Clinical evaluation of 3D/3D MRI-CBCT automatching on brain tumors for online patient setup verification - A step towards MRI-based treatment planning

    DEFF Research Database (Denmark)

    Buhl, Sune K.; Duun-Christensen, Anne Katrine; Kristensen, Brian H.

    2010-01-01

    Background. Magnetic Resonance Imaging (MRI) is often used in modern day radiotherapy (RT) due to superior soft tissue contrast. However, treatment planning based solely on MRI is restricted due to e. g. the limitations of conducting online patient setup verification using MRI as reference....... In this study 3D/3D MRI-Cone Beam CT (CBCT) automatching for online patient setup verification was investigated. Material and methods. Initially, a multi-modality phantom was constructed and used for a quantitative comparison of CT-CBCT and MRI-CBCT automatching. Following the phantom experiment three patients...

  10. A positioning QA procedure for 2D/2D (kV/MV) and 3D/3D (CT/CBCT) image matching for radiotherapy patient setup.

    Science.gov (United States)

    Guan, Huaiqun; Hammoud, Rabih; Yin, Fang-Fang

    2009-10-06

    A positioning QA procedure for Varian's 2D/2D (kV/MV) and 3D/3D (planCT/CBCT) matching was developed. The procedure was to check: (1) the coincidence of on-board imager (OBI), portal imager (PI), and cone beam CT (CBCT)'s isocenters (digital graticules) to a linac's isocenter (to a pre-specified accuracy); (2) that the positioning difference detected by 2D/2D (kV/MV) and 3D/3D(planCT/CBCT) matching can be reliably transferred to couch motion. A cube phantom with a 2 mm metal ball (bb) at the center was used. The bb was used to define the isocenter. Two additional bbs were placed on two phantom surfaces in order to define a spatial location of 1.5 cm anterior, 1.5 cm inferior, and 1.5 cm right from the isocenter. An axial scan of the phantom was acquired from a multislice CT simulator. The phantom was set at the linac's isocenter (lasers); either AP MV/R Lat kV images or CBCT images were taken for 2D/2D or 3D/3D matching, respectively. For 2D/2D, the accuracy of each device's isocenter was obtained by checking the distance between the central bb and the digital graticule. Then the central bb in orthogonal DRRs was manually moved to overlay to the off-axis bbs in kV/MV images. For 3D/3D, CBCT was first matched to planCT to check the isocenter difference between the two CTs. Manual shifts were then made by moving CBCT such that the point defined by the two off-axis bbs overlay to the central bb in planCT. (PlanCT can not be moved in the current version of OBI1.4.) The manual shifts were then applied to remotely move the couch. The room laser was used to check the accuracy of the couch movement. For Trilogy (or Ix-21) linacs, the coincidence of imager and linac's isocenter was better than 1 mm (or 1.5 mm). The couch shift accuracy was better than 2 mm.

  11. Calculated electronic properties of ordered alloys a handbook : the element and their 3d/3d and 4d/4d alloys

    CERN Document Server

    Moruzzi, VL

    1995-01-01

    This is a handbook of calculated electronic properties of elements and of 3d/3d and 4d/4d ordered alloys. The book derives the ground-state or equilibrium properties of the metallic elements in both bcc and fcc structures, and of existing and nonexisting ordered binary transition-metal alloys in CsCl, CuAu, and Cu 3 Au structures by the analysis of binding curves, or total energy vs. volume curves, calculated from first-principles augmented-spherical-wave methods. The calculated properties, energy bands along symmetry lines in the respective Brillouin zones, and the total and I-decomposed dens

  12. Soil emissivity and reflectance spectra measurements.

    Science.gov (United States)

    Sobrino, José A; Mattar, Cristian; Pardo, Pablo; Jiménez-Muñoz, Juan C; Hook, Simon J; Baldridge, Alice; Ibañez, Rafael

    2009-07-01

    We present an analysis of the laboratory reflectance and emissivity spectra of 11 soil samples collected on different field campaigns carried out over a diverse suite of test sites in Europe, North Africa, and South America from 2002 to 2008. Hemispherical reflectance spectra were measured from 2.0 to 14 microm with a Fourier transform infrared spectrometer, and x-ray diffraction analysis (XRD) was used to determine the mineralogical phases of the soil samples. Emissivity spectra were obtained from the hemispherical reflectance measurements using Kirchhoff's law and compared with in situ radiance measurements obtained with a CIMEL Electronique CE312-2 thermal radiometer and converted to emissivity using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) temperature and emissivity separation algorithm. The CIMEL has five narrow bands at approximately the same positions as the ASTER. Results show a root mean square error typically below 0.015 between laboratory emissivity measurements and emissivity measurements derived from the field radiometer.

  13. Soil emissivity and reflectance spectra measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sobrino, Jose A.; Mattar, Cristian; Pardo, Pablo; Jimenez-Munoz, Juan C.; Hook, Simon J.; Baldridge, Alice; Ibanez, Rafael

    2009-07-01

    We present an analysis of the laboratory reflectance and emissivity spectra of 11 soil samples collected on different field campaigns carried out over a diverse suite of test sites in Europe, North Africa, and South America from 2002 to 2008. Hemispherical reflectance spectra were measured from 2.0 to 14 {mu}m with a Fourier transform infrared spectrometer, and x-ray diffraction analysis (XRD) was used to determine the mineralogical phases of the soil samples. Emissivity spectra were obtained from the hemispherical reflectance measurements using Kirchhoff's law and compared with in situ radiance measurements obtained with a CIMEL Electronique CE312-2 thermal radiometer and converted to emissivity using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) temperature and emissivity separation algorithm. The CIMEL has five narrow bands at approximately the same positions as the ASTER. Results show a root mean square error typically below 0.015 between laboratory emissivity measurements and emissivity measurements derived from the field radiometer.

  14. Martian Analogues Emissivity Spectra From the Berlin Emissivity Database (BED)

    Science.gov (United States)

    Maturilli, A.; Helbert, J.; Moroz, L.

    2006-12-01

    Remote sensing infrared spectroscopy is the principal field of investigation for planetary surfaces composition. Past, present and future missions to bodies in the solar system include in their payload instruments measuring the emerging radiation in the infrared range. For the interpretation of the measured data an emissivity spectral library of planetary analog materials is needed. The Berlin Emissivity Database (BED) currently contains emissivity spectra of plagioclase and potassium feldspars, low Ca and high Ca pyroxenes, olivine, elemental sulphur, and Martian analogue minerals, measured in the wavelength range from 7 to 22 microns as a function of particle size. For each sample we measured the spectra of four particle size separates ranging from 0 to 250 microns. The device we used is built at DLR (Berlin) and is coupled to a Fourier transform infrared spectrometer (Bruker IFS 88), purged with dry air and equipped with a cooled detector (MCT). All spectra were acquired with a spectral resolution of 4 cm-1. We present here the results of our analysis on well knew and characterized Martian analogue minerals: JSC Mars-1, Salten Skov, and Palagonite from Mauna Kea, Hawaii. We are currently working to upgrade our emissivity facility. A new spectrometer (Bruker VERTEX 80v) and new detectors will allow us to measure the emissivity of samples in the wavelength range from 1 to 50 microns, even in a vacuum environment.

  15. Infra-red reflectance and emissivity spectra of nanodiamonds

    OpenAIRE

    MATURILLI, A.; A. A Shiryaev; Kulakova, I I; Helbert, J.

    2012-01-01

    Reflectance and emissivity spectra of nanodiamonds powder were measured in a dedicated setup at temperatures up to 873 K. The spectra are characterised by presence of sharp bands due to surface-bound functional groups. Thermal desorption of oxygen-containing groups lead to corresponding spectral changes. The maximal emissivity of nanodiamond powder reaches 0.985.

  16. Thermal Emission and Albedo Spectra of Super Earths with Flat Transmission Spectra

    CERN Document Server

    Morley, Caroline V; Marley, Mark S; Zahnle, Kevin; Line, Michael; Kempton, Eliza; Lewis, Nikole; Cahoy, Kerri

    2015-01-01

    Planets larger than Earth and smaller than Neptune are some of the most numerous in the galaxy, but observational efforts to understand this population have proved challenging because optically thick clouds or hazes at high altitudes obscure molecular features (Kreidberg et al. 2014b). We present models of super Earths that include thick clouds and hazes and predict their transmission, thermal emission, and reflected light spectra. Very thick, lofted clouds of salts or sulfides in high metallicity (1000x solar) atmospheres create featureless transmission spectra in the near-infrared. Photochemical hazes with a range of particle sizes also create featureless transmission spectra at lower metallicities. Cloudy thermal emission spectra have muted features more like blackbodies, and hazy thermal emission spectra have emission features caused by an inversion layer at altitudes where the haze forms. Close analysis of reflected light from warm (~400-800 K) planets can distinguish cloudy spectra, which have moderate ...

  17. Double-Resonance Facilitated Decomposion of Emission Spectra

    Science.gov (United States)

    Kato, Ryota; Ishikawa, Haruki

    2016-06-01

    Emission spectra provide us with rich information about the excited-state processes such as proton-transfer, charge-transfer and so on. In the cases that more than one excited states are involved, emission spectra from different excited states sometimes overlap and a decomposition of the overlapped spectra is desired. One of the methods to perform a decomposition is a time-resolved fluorescence technique. It uses a difference in time evolutions of components involved. However, in the gas-phase, a concentration of the sample is frequently too small to carry out this method. On the other hand, double-resonance technique is a very powerful tool to discriminate or identify a common species in the spectra in the gas-phase. Thus, in the present study, we applied the double-resonance technique to resolve the overlapped emission spectra. When transient IR absorption spectra of the excited state are available, we can label the population of the certain species by the IR excitation with a proper selection of the IR wavenumbers. Thus, we can obtain the emission spectra of labeled species by subtracting the emission spectra with IR labeling from that without IR. In the present study, we chose the charge-transfer emission spectra of cyanophenyldisilane (CPDS) as a test system. One of us reported that two charge-transfer (CT) states are involved in the intramolecular charge-transfer (ICT) process of CPDS-water cluster and recorded the transient IR spectra. As expected, we have succeeded in resolving the CT emission spectra of CPDS-water cluster by the double resonance facilitated decomposion technique. In the present paper, we will report the details of the experimental scheme and the results of the decomposition of the emission spectra. H. Ishikawa, et al., Chem. Phys. Phys. Chem., 9, 117 (2007).

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

    Science.gov (United States)

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

    1987-03-01

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

  19. Spreadsheet-Based Program for Simulating Atomic Emission Spectra

    Science.gov (United States)

    Flannigan, David J.

    2014-01-01

    A simple Excel spreadsheet-based program for simulating atomic emission spectra from the properties of neutral atoms (e.g., energies and statistical weights of the electronic states, electronic partition functions, transition probabilities, etc.) is described. The contents of the spreadsheet (i.e., input parameters, formulas for calculating…

  20. A Correlation Between Stellar Activity and Hot Jupiter Emission Spectra

    CERN Document Server

    Knutson, Heather A; Isaacson, Howard

    2010-01-01

    We present evidence for a correlation between the observed properties of hot Jupiter emission spectra and the activity levels of the host stars measured using Ca II H & K emission lines. We find that planets with dayside emission spectra that are well-described by standard, non-inverted 1D atmosphere models with water in absorption (HD 189733, TrES-1, TrES-3) orbit chromospherically active stars, while planets with emission spectra that are consistent with the presence of a high-altitude temperature inversion and water in emission orbit quieter stars. We propose that the increased UV flux received by planets orbiting active stars destroys the compounds responsible for the formation of the observed temperature inversions. We also derive a model-independent method for differentiating between these two atmosphere types using the secondary eclipse depths measured in the 3.6 and 4.5 micron bands on the Spitzer Space Telescope, and argue that the observed correlation is independent of the inverted/non-inverted ...

  1. Interpreting the Ionization Sequence in AGN Emission-Line Spectra

    CERN Document Server

    Richardson, Chris T; Baldwin, Jack A; Hewett, Paul C; Ferland, Gary J

    2013-01-01

    We investigate the physical cause of the great range in the ionization level seen in the spectra of narrow lined active galactic nuclei (AGN). Mean field independent component analysis identifies examples of individual SDSS galaxies whose spectra are not dominated by emission due to star formation (SF), which we designate as AGN. We assembled high S/N ratio composite spectra of a sequence of these AGN defined by the ionization level of their narrow-line regions (NLR), extending down to very low-ionization cases. We used a local optimally emitting cloud (LOC) model to fit emission-line ratios in this AGN sequence. These included the weak lines that can be measured only in the co-added spectra, providing consistency checks on strong line diagnostics. After integrating over a wide range of radii and densities our models indicate that the radial extent of the NLR is the major parameter in determining the position of high to moderate ionization AGN along our sequence, providing a physical interpretation for their ...

  2. Simulation of UIB spectra with IR emission from CHONS molecules

    CERN Document Server

    Papoular, Renaud

    2012-01-01

    The present work purports to identify candidate carriers of the UIBs. This requires a procedure for the computation of the emission spectrum of any given candidate. The procedure used here consists in exciting the carrier into a state of internal vibration, waiting until the system has reached dynamic equilibrium and, then, monitoring the time variations of the overall electric dipole moment associated with this vibration. The emission spectrum is shown to be simply related to the FT of these variations. This procedure was applied to more than 100 different chemical structures, inspired by the exhaustive experimental and theoretical analyses of Kerogens, the terrestrial sedimentary matter, which is known to be mainly composed of C, H, O, N and S atoms. From this data base, 21 structures were extracted, which fall in 4 classes, each of which contributes preferentially to one of the main UIBs. Summing their adequately weighted spectra delivers an emission spectrum which indeed exhibits the main UIB features (al...

  3. Helium shells and faint emission lines from slitless flash spectra.

    Science.gov (United States)

    Bazin, Cyril; Koutchmy, Serge

    2013-05-01

    At the time of the two last solar total eclipses of August 1st, 2008 in Siberia and July 11th, 2010 in French Polynesia, high frame rate CCD flash spectra were obtained. These eclipses occurred in quiet Sun period and after. The slitless flash spectra show two helium shells, in the weak Paschen α 4686 Å line of the ionized helium HeII and in the neutral helium HeI line at 4713 Å. The extensions of these helium shells are typically 3 Mm. In prominences, the extension of the interface with the corona is much more extended. The observations and analysis of these lines can properly be done only in eclipse conditions, when the intensity threshold reaches the coronal level, and the parasitic scattered light is virtually zero. Under the layers of 1 Mm above the limb, many faint low FIP lines were also seen in emission. These emission lines are superposed on the continuum containing absorption lines. The solar limb can be defined using the weak continuum appearing between the emission lines at the time of the second and third contact. The variations of the singly ionized iron line, the HeI and HeII lines and the continuum intensity are analyzed. The intensity ratio of ionized to neutral helium is studied for evaluating the ionization rate in low layers up to 2 Mm and also around a prominence.

  4. Helium shells and faint emission lines from slitless flash spectra

    Directory of Open Access Journals (Sweden)

    Cyril Bazin

    2013-05-01

    Full Text Available At the time of the two last solar total eclipses of August 1st, 2008 in Siberia and July 11th, 2010 in French Polynesia, high frame rate CCD flash spectra were obtained. These eclipses occurred in quiet Sun period and after. The slitless flash spectra show two helium shells, in the weak Paschen α 4686 Å line of the ionized helium HeII and in the neutral helium HeI line at 4713 Å. The extensions of these helium shells are typically 3 Mm. In prominences, the extension of the interface with the corona is much more extended. The observations and analysis of these lines can properly be done only in eclipse conditions, when the intensity threshold reaches the coronal level, and the parasitic scattered light is virtually zero. Under the layers of 1 Mm above the limb, many faint low FIP lines were also seen in emission. These emission lines are superposed on the continuum containing absorption lines. The solar limb can be defined using the weak continuum appearing between the emission lines at the time of the second and third contact. The variations of the singly ionized iron line, the HeI and HeII lines and the continuum intensity are analyzed. The intensity ratio of ionized to neutral helium is studied for evaluating the ionization rate in low layers up to 2 Mm and also around a prominence.

  5. Gravitational Redshift of Emission Lines in the AGN Spectra

    CERN Document Server

    Bon, Nataša; Marziani, Paola; Jovanović, Predrag

    2016-01-01

    The detection of gravitationally redshifted optical emission lines has been reported just for a few active galaxies. In this paper we give a short overview of studies that analyzed or exploited the detection of the gravitational redshift in optical AGN spectra. In addition, we tested the consistency of gravitational redshift as the physical origin of the redward shifts observed in their spectra using a sample of $\\approx$ 50 Hamburg-ESO intermediate to high redshift quasars that are among the most luminous quasars known ($10^{47} \\lesssim L \\lesssim 10^{48}$ erg/s), and are expected to host very massive black holes. To this aim we modeled the line profile with accretion disk models around a black hole.

  6. Inferring physical properties of galaxies from their emission line spectra

    CERN Document Server

    Ucci, Graziano; Gallerani, Simona; Pallottini, Andrea

    2016-01-01

    We present a new approach based on Supervised Machine Learning (SML) algorithms to infer key physical properties of galaxies (density, metallicity, column density and ionization parameter) from their emission line spectra. We introduce a numerical code (called GAME, GAlaxy Machine learning for Emission lines) implementing this method and test it extensively. GAME delivers excellent predictive performances, especially for estimates of metallicity and column densities. We compare GAME with the most widely used diagnostics (e.g. R$_{23}$, [NII]$\\lambda$6584 / H$\\alpha$ indicators) showing that it provides much better accuracy and wider applicability range. GAME is particularly suitable for use in combination with Integral Field Unit (IFU) spectroscopy, both for rest-frame optical/UV nebular lines and far-infrared/sub-mm lines arising from Photo-Dissociation Regions. Finally, GAME can also be applied to the analysis of synthetic galaxy maps built from numerical simulations.

  7. Chemical Speciation via X-ray Emission Spectra

    Science.gov (United States)

    Ankudinov, A. L.; Rehr, J. J.; Elam, W. T.; Sieber, J. R.

    2002-03-01

    We have extended our calculations of lineshapes in x-ray emission and x-ray fluorescence (XRF) spectroscopy to investigate the dependence on formal oxidation state. We used the self-consistent x-ray spectroscopy code FEFF8.1 [1], which is based on a real-space Green's function formalism, to calculate the phosphorus K-M_2,3 line and the Cr K and L emission lines for a range of simple oxides. These lines exhibit changes depending on oxidation state. Convolution with an algorithm describing the response function of the spectrometer is necessary to compare to experimental measurements. The calculated spectra are compared to measured spectra and to other relevant calculations, e.g., Fujikawa and Kawai [2]. The comparisons thus far indicate that calculations and measurements together can yield a quantitative analysis of compounds. [1] A. L. Ankudinov and J. J. Rehr, Phys. Rev. B 62, 2437 (2000). [2] T. Fujikawa and J. Kawai, J. Phys. Soc. Japan 68, 4032 (1999).

  8. Spectra of hybrid synchrotron emission in hot black hole winds

    Science.gov (United States)

    Hayakawa, Ken; Fukue, Jun

    2015-12-01

    We solve radiative transfer to obtain the hybrid synchrotron spectra from a hot, optically thin black hole wind, by integrating the radiative transfer equation in the comoving frame and considering the relativistic effect of wind flow as well as the emission and absorption along the line-of-sight. We find two primary characteristics in the hybrid model: (1) a shoulder at low frequencies and (2) a power-law tail at high frequencies. Even if only 10-4 of the total electron energy is injected as non-thermal electrons, higher luminosity can be produced compared to the pure thermal model. Thus, there is a large difference between the pure thermal model and the hybrid one. In addition, as the wind velocity becomes large, the thermal peak of the comoving spectra shifts toward the high-frequency regime, due to the relativistic Doppler effect. As the wind velocity increases, on the other hand, the thermal peak of the observed spectra shifts toward the low-frequency regime, due to the redshifted part in the far side and limb side.

  9. Neutron emission profiles and energy spectra measurements at JET

    Energy Technology Data Exchange (ETDEWEB)

    Giacomelli, L. [JET-EFDA, Culham Science Centre, Abingdon, 0X14 3DB, United Kingdom and Department of Physics, Università degli Studi di Milano-Bicocca, Milano (Italy); Conroy, S. [JET-EFDA, Culham Science Centre, Abingdon, 0X14 3DB, United Kingdom and Department of Physics and Astronomy, Uppsala University, Uppsala (Sweden); Belli, F.; Riva, M. [Associazione EURATOM-ENEA sulla Fusione, Roma (Italy); Gorini, G. [Department of Physics, Università degli Studi di Milano-Bicocca, Milano, Italy and Istituto di Física del Plasma Piero Caldirola, Milan (Italy); Horton, L.; Joffrin, E.; Lerche, E.; Murari, A.; Popovichev, S.; Syme, B. [JET-EFDA, Culham Science Centre, Abingdon, 0X14 3DB (United Kingdom); Collaboration: JET EFDA Contributors

    2014-08-21

    The Joint European Toras (JET, Culham, UK) is the largest tokamak in the world. It is devoted to nuclear fusion experiments of magnetic confined Deuterium (D) or Deuterium-Tritium (DT) plasmas. JET has been upgraded over the years and recently it has also become a test facility of the components designed for ITER, the next step fusion machine under construction in Cadarache (France). JET makes use of many different diagnostics to measure the physical quantities of interest in plasma experiments. Concerning D or DT plasmas neutron production, various types of detectors are implemented to provide information upon the neutron total yield, emission profile and energy spectrum. The neutron emission profile emitted from the JET plasma poloidal section is reconstructed using the neutron camera (KN3). In 2010 KN3 was equipped with a new digital data acquisition system capable of high rate neutron measurements (<0.5 MCps). A similar instrument will be implemented on ITER and it is currently in its design phase. Various types of neutron spectrometers with different view lines are also operational on JET. One of them is a new compact spectrometer (KM12) based on organic liquid scintillating material which was installed in 2010 and implements a similar digital data acquisition system as for KN3. This article illustrates the measurement results of KN3 neutron emission profiles and KM 12 neutron energy spectra from the latest JET D experimental campaign C31.

  10. Common substructure in otoacoustic emission spectra of land vertebrates

    Science.gov (United States)

    Manley, Geoffrey A.; Köppl, Christine; Bergevin, Christopher

    2015-12-01

    In humans, a similar spectral periodicity is found in all otoacoustic emission types and in threshold fine structure. This may reflect travelling wave phase and reflectance from "structural roughness" in the organ of Corti, or entrainment and suppressive interactions between emissions. To further understand these phenomena, we have examined spontaneous otoacoustic emission (SOAE) spectra in 9 lizard species and the barn owl and find a comparable periodicity. Importantly, the frequency spacing between SOAE peaks was independent of the physical spacing and of the frequency space constants in hearing organs. In 9 lizard species, median spectral gaps lay between 219 and 461 Hz, with no correlation to papillar length (0.3 to 2.1 mm). Similarly in much longer organs: In humans (35 mm), SOAE spectral gaps vary up to 220 Hz at 4 kHz; in the barn owl (11 mm), the median SOAE peak spacing was 395Hz. In the barn owl, a very large space constant between 5 and 10 kHz (5 mm/octave) contrasts with stable SOAE spacing between 1 and 11 kHz. Similar SOAE spectral gaps across all species suggests they represent a basic frequency grating revealing local phase-dependent interactions between active hair cells, a feature not determined by macro-structural anatomy. Emission spectral spacing is independent of cochlear length, of the frequency space constant, of the existence of travelling waves or of a tectorial membrane. Our data suggest that there are greater similarities between frequency selectivity reflected at the level of the hair cells' spontaneous mechanical output (OAEs) than there are at the level of the auditory nerve, where macro-structural anatomy links hair-cell activity differentially to the neural output. Apparently, all hair-cell arrays show a similar frequency substructure not directly replicated in neural tuning.

  11. Polarization of electron cyclotron emission spectra in LHD

    Energy Technology Data Exchange (ETDEWEB)

    Vries, P.C. de; Nagayama, Y.; Kawahata, K.; Inagaki, S.; Sasao, H. [National Inst. for Fusion Science, Toki, Gifu (Japan); Nagasaki, K.

    1999-07-01

    Electron cyclotron emission (ECE) can be used to determine the electron temperature profile in magnetized plasmas. The complex structure of the magnetic field configuration in the Large Helical Device (LHD), which has a large shear, complicates the analysis of the ECE spectrum. In a sheared magnetic field the propagation of X and O-mode polarization through the plasma are coupled, causing mode conversion and polarization rotation. Mode scrambling is also caused by wall reflections. In this report, this mode conversion in LHD is numerically analyzed. It was found that at low density mode conversion scrambles the ECE spectra. However, at higher density (n{sub eo} > 1.0{center_dot}10{sup 19} m{sup -3}) the polarization mode is found to rotate with the sheared magnetic field, yielding only a negligible mode conversion. Wall reflections are found to depolarize the ECE spectrum. Notwithstanding the LHD magnetic configuration, it is shown that temperature profiles could be revealed from the ECE spectra. (author)

  12. Analysis of neutral hydrogenic emission spectra in a tokamak

    Science.gov (United States)

    Ko, J.; Chung, J.; Jaspers, R. J. E.

    2015-10-01

    Balmer-α radiation by the excitation of thermal and fast neutral hydrogenic particles has been investigated in a magnetically confined fusion device, or tokamak, from the Korea Superconducting Tokamak Advanced Research (KSTAR). From the diagnostic point of view, the emission from thermal neutrals is associated with passive spectroscopy and that from energetic neutrals that are usually injected from the outside of the tokamak to the active spectroscopy. The passive spectroscopic measurement for the thermal Balmer-α emission from deuterium and hydrogen estimates the relative concentration of hydrogen in a deuterium-fueled plasma and therefore, makes a useful tool to monitor the vacuum wall condition. The ratio of hydrogen to deuterium obtained from this measurement qualitatively correlates with the energy confinement of the plasma. The Doppler-shifted Balmer-α components from the fast neutrals features the spectrum of the motional Stark effect (MSE) which is an essential principle for the measurement of the magnetic pitch angle profile. Characterization of this active MSE spectra, especially with multiple neutral beam lines crossing along the observation line of sight, has been done for the guideline of the multi-ion-source heating beam operation and for the optimization of the narrow bandpass filters that are required for the polarimeter-based MSE diagnostic system under construction at KSTAR.

  13. New downshifted maximum in stimulated electromagnetic emission spectra

    Science.gov (United States)

    Sergeev, Evgeny; Grach, Savely

    A new spectral maximum in spectra of stimulated electromagnetic emission of the ionosphere (SEE, [1]) was detected in experiments at the SURA facility in 2008 for the pump frequencies f0 4.4-4.5 MHz, most stably for f0 = 4.3 MHz, the lowest possible pump frequency at the SURA facility. The new maximum is situated at frequency shifts ∆f -6 kHz from the pump wave frequency f0 , ∆f = fSEE - f0 , somewhat closer to the f0 than the well known [2,3] Downshifted Maximum in the SEE spectrum at ∆f -9 kHz. The detection and detailed study of the new feature (which we tentatively called the New Downshifted Maximum, NDM) became possible due to high frequency resolution in spectral analysis. The following properties of the NDM are established. (i) The NDM appears in the SEE spectra simultaneously with the DM and UM features after the pump turn on (recall that the less intensive Upshifted Maximum, UM, is situated at ∆f +(6-8) kHz [2,3]). The NDM can't be attributed to 1 DM [4] or Narrow Continuum Maximum (NCM, 2 [5]) SEE features, as well as to splitted DM near gyroharmonics [2]. (ii) The NDM is observed as prominent feature for maximum pump power of the SURA facility P ≈ 120 MW ERP, for which the DM is almost covered by the Broad Continuum SEE feature [2,3]. For P ˜ 30-60 MW ERP the DM and NDM have comparable intensities. For the lesser pump power the DM prevails in the SEE spectrum, while the NDM becomes invisible being covered by the thermal Narrow Continuum feature [2]. (iii) The NDM is exactly symmetrical for the UM relatively to f0 when the former one is observed, although the UM frequency offset increases up to ∆fUM ≈ +9 kHz with a decrease of the pump power up to P ≈ 4 MW ERP. The DM formation in the SEE spectrum is attributed to a three-wave interaction between the upper and lower hybrid waves in the ionosphere, and the lower hybrid frequency ( 7 kHz) determines the frequency offset of the DM high frequency flank [2,6]. The detection of the NDM with

  14. Measuring the response of canopy emissivity spectra to leaf area index variation using thermal hyperspectral data

    Science.gov (United States)

    Neinavaz, Elnaz; Darvishzadeh, Roshanak; Skidmore, Andrew K.; Groen, Thomas A.

    2016-12-01

    One of the plant biophysical factors affecting the canopy spectral reflectance of plants in the optical domain to receive research attention in recent decades is leaf area index (LAI). Although it is expected that the value of LAI affects the emission of radiation, it not known how. To our knowledge, the effect of LAI on plant canopy emissivity spectra has not yet been investigated in the thermal infrared region (TIR 8-14 μm). The overall aim of this study was to demonstrate the effect of LAI on canopy emissivity spectra of different species at the nadir position. The 279 spectral wavebands in the TIR domain were measured under controlled laboratory condition using a MIDAC spectrometer for four plant species. The corresponding LAI of each measurement was destructively calculated. We found a positive correlation between canopy emissivity spectra at various LAI values, indicating that emissivity increases concomitantly with LAI value. The canopy emissivity spectra of the four species were found to be statistically different at various wavebands even when the LAI values of the species were similar. It seems that other biophysical or biochemical factors also contribute to canopy emissivity spectra: this merits further investigation. We not only quantify the role of LAI on canopy emissivity spectra for the first time, but also demonstrate the potential of using hyperspectral thermal data to estimate LAI of plant species.

  15. 3D,3D,全家都3D!

    Institute of Scientific and Technical Information of China (English)

    春天

    2011-01-01

    不难发现最近周围的男人突然都开始对3D这个词有了难以名状的兴趣,这绝对要归功于近期在香港热映的某部3D电影。随着祼眼3D等技术的问世,3D被应用到了越来越多的领域。

  16. Equilibrium excited state and emission spectra of molecular aggregates from the hierarchical equations of motion approach.

    Science.gov (United States)

    Jing, Yuanyuan; Chen, Liping; Bai, Shuming; Shi, Qiang

    2013-01-28

    The hierarchical equations of motion (HEOM) method was applied to calculate the emission spectra of molecular aggregates using the Frenkel exciton model. HEOM equations for the one-exciton excited state were first propagated until equilibration. The reduced density operator and auxiliary density operators (ADOs) were used to characterize the coupled system-bath equilibrium. The dipole-dipole correlation functions were then calculated to obtain the emission spectra of model dimers, and the B850 band of light-harvesting complex II (LH2) in purple bacteria. The effect of static disorder on equilibrium excited state and the emission spectra of LH2 was also explicitly considered. Several approximation schemes, including the high temperature approximation (HTA) of the HEOM, a modified version of the HTA, the stochastic Liouville equation approach, the perturbative time-local and time-nonlocal generalized quantum master equations, were assessed in the calculation of the equilibrium excited state and emission spectra.

  17. Spectra and rates of bremsstrahlung neutrino emission in stars

    Science.gov (United States)

    Guo, Gang; Qian, Yong-Zhong

    2016-08-01

    We calculate the energy-differential rate for neutrino emission from electron-nucleus bremsstrahlung in stellar interiors taking into account the effects of electron screening and ionic correlations. We compare the energy-differential and the net rates, as well as the average ν¯e and ν¯x(x =μ ,τ ) energies, for this process with those for e± pair annihilation, plasmon decay, and photoneutrino emission over a wide range of temperature and density. We also compare our updated energy loss rates for the above thermal neutrino emission processes with the fitting formulas widely used in stellar evolution models and determine the temperature and density domain in which each process dominates. We discuss the implications of our results for detection of ν¯e from massive stars during their presupernova evolution and find that pair annihilation makes the predominant contribution to the signal from the thermal emission processes.

  18. Imaging Emission Spectra with Handheld and Cellphone Cameras

    Science.gov (United States)

    Sitar, David

    2012-01-01

    As point-and-shoot digital camera technology advances it is becoming easier to image spectra in a laboratory setting on a shoestring budget and get immediate results. With this in mind, I wanted to test three cameras to see how their results would differ. Two undergraduate physics students and I used one handheld 7.1 megapixel (MP) digital Cannon…

  19. Emission spectra of YAG:Er3+ under pulse laser-thermal excitation

    Science.gov (United States)

    Marchenko, V. M.; Shakir, Yu. A.

    2016-12-01

    Spectra and kinetics of emission of YAG:0.5% Er3+ monocrystal in visible and NIR ranges were investigated under laser-thermal excitation by the pulses of CO2 laser of 100 ns duration at wavelength λ = 10,6 μμm. Kinetics of integral emission was interpreted.

  20. Influence of pure dephasing on emission spectra from single photon sources

    DEFF Research Database (Denmark)

    Næsby Rasmussen, Andreas; Skovgård, Troels Suhr; Kristensen, Philip Trøst

    2008-01-01

    We investigate the light-matter interaction of a quantum dot with the electromagnetic field in a lossy microcavity and calculate emission spectra for nonzero detuning and dephasing. It is found that dephasing shifts the intensity of the emission peaks for nonzero detuning. We investigate the char...

  1. Action and Emission Spectra of the Luminescence of Green PlantMaterials

    Energy Technology Data Exchange (ETDEWEB)

    Tollin, G.; Fujimori, E.; Calvin, Melvin

    1957-12-29

    The action and emission spectra of the delayed light emission from Chlorella, Nostoc, and spinach chloroplasts have been measured. The action spectra for Chlorella and for spinach chloroplasts are quite similar to the absorption spectra of these materials. The action spectrum for Nostoc, on the other hand, shows a relatively low activity for chlorophyll and carotenoids and a high activity for phycocyanin. The emission spectra of these materials demonstrates that the luminescence is the result of a transition between the first excited singlet state and the ground state of chlorophyll. Low-temperature studies suggest that the triplet state of chlorophyll is not involved at all in the luminescence of spinach chloroplasts. There is some indication that part of the light emitted from Nostoc is due to a phycocyanin transition.

  2. Emission spectra of alkali-metal (K,Na,Li)-He exciplexes in cold helium gas

    Science.gov (United States)

    Enomoto, K.; Hirano, K.; Kumakura, M.; Takahashi, Y.; Yabuzaki, T.

    2004-01-01

    We have observed emission spectra of excimers and exciplexes composed of a light alkali-metal atom in the first excited state and 4He atoms [K*Hen (n=1-6), Na*Hen (n=1-4), and Li*Hen (n=1,2)] in cryogenic He gas (the temperature 2 Kspectra for the different number of He atoms were well separated, so that their assignment could be made experimentally. Comparing with the spectra of K*Hen, we found that the infrared emission spectrum of the K atom excited in liquid He was from K*He6. To confirm the assignment, we have also carried out ab initio calculation of adiabatic potential curves and peak positions of the emission spectra of the exciplexes.

  3. Spectra and rates of bremsstrahlung neutrino emission in stars

    CERN Document Server

    Guo, Gang

    2016-01-01

    We calculate the energy-differential rate for neutrino emission from electron-nucleus bremsstrahlung in stellar interiors taking into account the effects of electron screening and ionic correlations. We compare the energy-differential and the net rates, as well as the average $\\bar{\

  4. Effects of grain boundary characteristics of steel on magnetoacoustic emission spectra

    Science.gov (United States)

    Namkung, M.; Yost, W. T.; Utrata, D.; Grainger, J. L.; Kushnick, P. W.

    1989-01-01

    Consideration is given to the effects of grain boundary characteristics on the properties of a magnetoacoustic emission spectra obtained by external ac magnetic field-driven domain wall motions. In studies with HY80 steel samples, it is found that the domain wall-defect interaction enhances as more grain boundary is introduced. The enhancement of the domain wall-defect interaction generates high amplitude magnetoacoustic emission pulses and reduces the rate of magnetoacoustic emission events by limiting domain wall motions.

  5. Tau-REx II: Retrieval of emission spectra

    CERN Document Server

    Waldmann, Ingo P; Rocchetto, Marco; Barton, Emma J; Yurchenko, Sergey N; Tennyson, Jonathan

    2015-01-01

    Tau-REx (Tau Retrieval of Exoplanets) is a novel, fully Bayesian atmospheric retrieval code custom built for extrasolar atmospheres. In Waldmann et al. (2015) the transmission spectroscopic case was introduced, here we present the emission spectroscopy spectral retrieval for the Tau-REx framework. Compared to transmission spectroscopy, the emission case is often significantly more degenerate due to the need to retrieve the full atmospheric temperature-pressure (TP) profile. This is particularly true in the case of current measurements of exoplanetary atmospheres, which are either of low signal-to-noise, low spectral resolution or both. Here we present a new way of combining two existing approaches to the modelling of the said TP profile: 1) the parametric profile, where the atmospheric TP structure is analytically approximated by a few model parameters, 2) the Layer-by-Layer approach, where individual atmospheric layers are modelled. Both these approaches have distinct advantages and disadvantages in terms of...

  6. Identifying plant species using MIR and TIR (2 - 14 μm) emissivity spectra

    Science.gov (United States)

    Ullah, S.; Schlerf, M.; Skidmore, A. K.; Hecker, C.

    2012-04-01

    Tittle: Identifying plant species using MIR and TIR (2 - 14 µm) emissivity spectra Identification plant species using remote sensing is generally limited by the similarity of their reflectance spectra in the visible, NIR and SWIR domains. Laboratory measured emissivity spectra in the mid to thermal infrared (MIR-TIR; 2 µm - 14 µm) shows significant differences. The laboratory emissivity spectra of thirteen common broad leaved species, comprising 3024 spectral bands in the MIR and TIR, were analyzed. For each wavelength the differences between the species were tested for significance using the one way analysis of variance (ANOVA) with the post-hoc Tukey HSD test. The emissivity spectra of the analysed species were found to be statistically different at various wavebands. Subsequently, six spectral bands were selected (based on the histogram of separable pairs of species for each waveband) to quantify the separability between each species pair based on the Jefferies Matusita (JM) distance. Out of 78 combinations, 76 pairs had a significantly different JM distance. Using the selected six wavebands for multiple plant species, overall classification accuracy of 92 % was achieved. This means that careful selection of hyperspectral bands in the MIR and TIR (2.5 µm - 14 µm) results in reliable species discrimination. Keywords: Spectral emissivity, J-M distance, ANOVA, Tukey HSD, spectral separability, Kirchhoff law

  7. Structural and time resolved emission spectra of Er 3+: Silver lead borate glass

    Science.gov (United States)

    Coelho, João; Hungerford, Graham; Hussain, N. Sooraj

    2011-08-01

    The structural properties of Er 3+: silver lead borate glass is assessed by means of SEM, X-ray mapping, EDS and Raman analysis. In order to verify the time dependency of emission spectra, steady-state luminescence spectroscopy (SSLS) and time-resolved emission spectroscopy (TRES) studies have been performed. The stimulated emission cross-sections for the NIR emission transition 4I 13/2 → 4I 15/2 (1535 nm) at 970 nm excitation are reported. The decay times were obtained by fitting one ( τm = 0.301 ms) and two ( τm1 = 0.141 ms, τm2 = 0.368 ms) distributions for the NIR transition. Furthermore, by making use of TRES measurements the decay associated spectra were obtained allowing the time dependency for the different emission bands to be elucidated.

  8. Far-infrared emission spectra of selected gas-phase PAHs: Spectroscopic fingerprints

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, K.; Guo, B.; Colarusso, P.; Bernath, P.F. [Univ. of Waterloo, Ontario (Canada)

    1996-10-25

    The emission spectra of the gaseous polycyclic aromatic hydrocarbons (PAHs) naphthalene, chrysene, and pyrene were recorded in the far-infrared (far-IR) region. The vibrational bands that lie in the far IR are unique for each PAH molecule and allow discrimination among the three PAH molecules. The far-IR PAH spectra, therefore, may prove useful in the assignment of unidentified spectral features from astronomical objects. 23 refs., 1 fig., 1 tab.

  9. On the sharpness of gamma-ray burst prompt emission spectra

    CERN Document Server

    Yu, Hoi-Fung; Greiner, Jochen; Sari, Re'em; Bhat, P Narayana; von Kienlin, Andreas; Paciesas, William S; Preece, Robert D

    2015-01-01

    We aim to obtain a measure of the curvature of time-resolved spectra that can be compared directly to theory. This tests the ability of models such as synchrotron emission to explain the peaks or breaks of GBM prompt emission spectra. We take the burst sample from the official Fermi GBM GRB time-resolved spectral catalog. We re-fit all spectra with a measured peak or break energy in the catalog best-fit models in various energy ranges, which cover the curvature around the spectral peak or break, resulting in a total of 1,113 spectra being analysed. We compute the sharpness angles under the peak or break of the triangle constructed under the model fit curves and compare to the values obtained from various representative emission models: blackbody, single-electron synchrotron, synchrotron emission from a Maxwellian or power-law electron distribution. We find that 35% of the time-resolved spectra are inconsistent with the single-electron synchrotron function, and 91% are inconsistent with the Maxwellian synchrot...

  10. Emission spectra of selected SSME elements and materials

    Science.gov (United States)

    Tejwani, Gopal D.; Vandyke, David B.; Bircher, Felix E.; Gardner, Donald G.; Chenevert, Donald J.

    1992-12-01

    Stennis Space Center (SSC) is pursuing the advancement of experimental techniques and theoretical developments in the field of plume spectroscopy for application to rocket development testing programs and engine health monitoring. Exhaust plume spectral data for the Space Shuttle Main Engine (SSME) are routinely acquired. The usefulness of this data depends upon qualitative and quantitative interpretation of spectral features and their correlation with the engine performance. A knowledge of the emission spectral characteristics of effluent materials in the exhaust plume is essential. A study of SSME critical components and their materials identified 30 elements and 53 materials whose engine exhaust plume spectral might be required. The most important were evaluated using SSC's Diagnostic Testbed Facility Thruster (DTFT), a 1200-lbf, liquid oxygen/gaseous hydrogen rocket engine which very nearly replicates the temperature and pressure conditions of the SSME exhaust plume in the first Mach diamond. This report presents the spectral data for the 10 most important elements and 27 most important materials which are strongly to moderately emitting in the DTFT exhaust plume. The covered spectral range is 300 to 426 nm and the spectral resolution is 0.25 nm. Spectral line identification information is provided and line interference effects are considered.

  11. Evolution of infrared spectra and optical emission spectra in hydrogenated silicon thin films prepared by VHF-PECVD

    Science.gov (United States)

    Hou, Guo-Fu; Geng, Xin-Hua; Zhang, Xiao-Dan; Sun, Jian; Zhang, Jian-Jun; Zhao, Ying

    2011-07-01

    A series of hydrogenated silicon thin films with varying silane concentrations have been deposited by using very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) method. The deposition process and the silicon thin films are studied by using optical emission spectroscopy (OES) and Fourier transfer infrared (FTIR) spectroscopy, respectively. The results show that when the silane concentration changes from 10% to 1%, the peak frequency of the Si-H stretching mode shifts from 2000 cm-1 to 2100 cm-1, while the peak frequency of the Si—H wagging—rocking mode shifts from 650 cm-1 to 620 cm-1. At the same time the SiH/Hα intensity ratio in the plasma decreases gradually. The evolution of the infrared spectra and the optical emission spectra demonstrates a morphological phase transition from amorphous silicon (a-Si:H) to microcrystalline silicon (μc-Si:H). The structural evolution and the μc-Si:H formation have been analyzed based on the variation of Hα and SiH intensities in the plasma. The role of oxygen impurity during the plasma process and in the silicon films is also discussed in this study.

  12. Study of Ultraviolet Emission Spectra in ZnO Thin Films

    Directory of Open Access Journals (Sweden)

    Y. M. Lu

    2013-01-01

    Full Text Available Photoluminescence (PL of ZnO thin films prepared on c-Al2O3 substrates by pulsed laser deposition (PLD are investigated. For all samples, roomtemperature (RT spectra show a strong band-edge ultraviolet (UV emission with a pronounced low-energy band tail. The origin of this UV emission is analyzed by the temperature dependence of PL spectra. The result shows that the UV emission at RT contains different recombination processes. At low temperature donor-bound exciton (D0X emission plays a major role in PL spectra, while the free exciton transition (FX gradually dominates the spectrum with increasing temperatures. It notes that at low temperature an emission band (FA appears in low energy side of D0X and FX and can survive up to RT. Further confirmation shows that the origin of the band FA can be attributed to the transitions of conduction band electrons to acceptors (e, A0, in which the acceptor binding energy is estimated to be approximately 121 meV. It is concluded that at room temperature UV emission originates from the corporate contributions of the free exciton and free electrons-to-acceptor transitions.

  13. Discernment of lint trash in raw cotton using multivariate analysis of excitation-emission luminescence spectra

    Science.gov (United States)

    Excitation-Emission luminescence spectra of basic (pH 12.5) phosphate buffer solution extracts were used to distinguish among botanical components of trash within seed cotton. All components were separated from whole plants removed from a field in southern New Mexico. Unfolded Principal Component An...

  14. Cassini VIMS Spectra of the Thermal Emission from Hot Spots Along Enceladus South Pole Fissures

    Science.gov (United States)

    Goguen, Jay D.; Buratti, Bonnie J.; Cassini VIMS Team

    2016-10-01

    Most of the south pole fissure region has not been directly illuminated by sunlight since the sub-solar point moved into the northern hemisphere in 2009, thereby eliminating the background of reflected sunlight at VIMS wavelengths and making the fissure thermal emission readily measureable. Since then, VIMS has measured spectra of at least 11 hot spots along the fissures. Most of these measurements were acquired in ride-along mode with CIRS as the prime instrument. During at least 2 encounters, VIMS and CIRS acquired simultaneous or near-simultaneous spectra of the same fissure location. VIMS spectra include multiple hot spots along Damascus, Baghdad, Cairo, and a likely hot spot on Alexandria.All of the VIMS spectra examined to date are consistent with this scenario of a self-regulating fissure maximum T~200 K with brighter VIMS emissions corresponding to fissures up to ~20 m wide. Emission from the warm fissure interior walls dominate the VIMS spectra with <15% contributed by conductive heating of the adjacent terrain at VIMS wavelengths.CIRS spectra report slightly cooler T's due to CIRS increased sensitivity to lower T emission at longer wavelengths and averaging over contributions from both the hottest and cooler areas. Combined analysis of the CIRS and VIMS spectra spanning 3 to 500 micron wavelengths promises to reveal the distribution of [T, area] near the fissures that cannot be spatially resolved. This [T, area] distribution holds the key to understanding how heat is transferred to the surface within a few 100 m of the fissures.The VIMS-detected emission is concentrated in localized hot spots along the fissures and does not seem to be distributed continuously along them. CIRS spectra suggest a more continuous distribution of the emission along the fissure length. Jets locations also are distributed along the fissure length and it appears that the VIMS-detected hot spots in general correlate with jet locations, but not all of the jet locations have been

  15. Behavior of porous silicon emission spectra during quenching by immersion in metal ion solutions

    Energy Technology Data Exchange (ETDEWEB)

    Andsager, D.; Hilliard, J.; Nayfeh, M.H. (Department of Physics, University of Illinois at Urbana-Champaign, 1110 W. Green Street, Urbana, Illinois 61801 (United States))

    1994-02-28

    The photoluminescence emission of porous silicon was regularly measured while immersed in dilute metal ion solutions of Cu, Ag, and Au. The emission spectra show progressive quenching that advances from the blue edge towards the red edge of the emission band, causing a continuous shift in the band center and a narrowing of its width. Auger electron spectroscopy data show that the penetration of the metal adsorbate into the porous layer correlates with the degree of quenching of the photoluminescence. These results are interpreted as a progression of the quenching of the photoluminescence inward from the surface of the sample toward the bulk.

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

    Science.gov (United States)

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

    2014-12-01

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

  17. Applications of Wigner high-order spectra in feature extraction of acoustic emission signals

    Institute of Scientific and Technical Information of China (English)

    Xiao Siwen; Liao Chuanjun; Li Xuejun

    2009-01-01

    The characteristics of typical AE signals initiated by mechanical component damages are analyzed. Based on the extracting principle of acoustic emission(AE) signals from damaged components, the paper introduces Wigner high-order spectra to the field of feature extraction and fault diagnosis of AE signals. Some main performances of Wigner bi-nary spectra, Wigner triple spectra and Wigner-Ville distribution (WVD) are discussed, including of time-frequency resolution, energy accumulation, reduction of crossing items and noise elimination. Wigncr triple spectra is employed to the fault diagnosis of rolling bearings with AE techniques. The fault features reading from experimental data analysis are clear, accurate and intuitionistic. The validity and accuracy of Wigner high-order spectra methods proposed agree quite well with simulation results. Simulation and research results indicate that wigncr high-order spectra is quite useful for condition monitoring and fault diagnosis in conjunction with AE technique, and has very important research and applica-tion values in feature extraction and faults diagnosis based on AE signals due to mechanical component damages.

  18. On the effect of emergence angle on emissivity spectra: application to small bodies

    Science.gov (United States)

    Maturilli, Alessandro; Helbert, Jörn; Ferrari, Sabrina; D'Amore, Mario

    2016-05-01

    Dependence of laboratory-measured emissivity spectra from the emergence angle is a subject that still needs a lot of investigations to be fully understood. Most of the previous work is based on reflectance measurements in the VIS-NIR spectral region and on emissivity measurements of flat, solid surfaces (mainly metals), which are not directly applicable to the analysis of remote sensing data. Small bodies in particular (c.f. asteroids Itokawa and 1999JU3, the respective targets of JAXA Hayabusa and Hayabusa 2 missions) have a very irregular surface; hence, the spectra from those rough surfaces are difficult to compare with laboratory spectra, where the observing geometry is always close to "nadir." At the Planetary Emissivity Laboratory of the German Aerospace Center (DLR), we have set up a series of spectral measurements to investigate this problem in the 1- to 16-µm spectral region. We measured the emissivity for two asteroid analogue materials (meteorite Millbillillie and a synthetic enstatite) in vacuum and under purged air, at surface temperature of 100 °C, for emergence angles of 0°, 5°, 10°, 20°, 30°, 40°, 50°, and 60°. Emissivity of a serpentinite slab, already used as calibration target for the MARA instrument on Hayabusa 2 MASCOT lander and for the thermal infrared imager spectrometer on Hayabusa 2 orbiter, was measured under the same conditions. Additionally, a second basalt slab was measured. Both slabs were not measured at 5° inclination. Complementary reflectance measurements of the four samples were taken. For all the samples measured, we found that for calibrated emissivity, significant variations from values obtained at nadir (0° emergence angle) appear only for emergence angles ≥40°. Reflectance measurements confirmed this finding, showing the same trend of variations.

  19. C-H Hot Bands in the Near-IR Emission Spectra of Leonids

    Science.gov (United States)

    Freund, F. T.; Scoville, J.; Holm, R.; Seelemann, R.; Freund, M. M.

    2002-01-01

    The reported infrared (IR) emission spectra from 1999 Leonid fireballs show a 3.4 micron C-H emission band and unidentified bands at longer wavelengths. Upon atmospheric entry, the Leonid meteorites were flash-heated to temperatures around 2400K, which would destroy any organics on the surface of the meteorite grains. We propose that the nu(sub )CH emission band in the Leonid emission spectra arises from matrix-embedded C(sub n)-H-O entities that are protected from instant pyrolysis. Our model is based on IR absorption nu(sub )CH bands, which we observed in laboratory-grown MgO and natural olivine single crystals, where they arise from C(sub n)-H-O units imbedded in the mineral matrix, indicative of aliphatic -CH2- and -CH3 organics. Instead of being pyrolyzed, the C(sub n)-H-O entities in the Leonid trails become vibrationally excited to higher levels n = 1, 2, 3 etc. During de-excitation they emit at 3.4 microns, due to the (0 => 1) transition, and at longer wavelengths, due to hot bands. As a first step toward verifying this hypothesis we measured the C-H vibrational manifold of hexane (C6H14). The calculated positions of the (2 => l ) , (3 => 2), and possibly (4 => 3) hot bands agree with the Leonid emission bands at 3.5, 3.8 and 4.l microns.

  20. Searching for Dwarf H Alpha Emission-line Galaxies within Voids III: First Spectra

    Science.gov (United States)

    Moody, J. Ward; Draper, Christian; McNeil, Stephen; Joner, Michael D.

    2017-02-01

    The presence or absence of dwarf galaxies with {M}r\\prime > -14 in low-density voids is determined by the nature of dark matter halos. To better understand what this nature is, we are conducting an imaging survey through redshifted Hα filters to look for emission-line dwarf galaxies in the centers of two nearby galaxy voids called FN2 and FN8. Either finding such dwarfs or establishing that they are not present is a significant result. As an important step in establishing the robustness of the search technique, we have observed six candidates from the survey of FN8 with the Gillett Gemini telescope and GMOS spectrometer. All of these candidates had emission, although none was Hα. The emission in two objects was the [O iii]λ4959, 5007 doublet plus Hβ, and the emission in the remaining four was the [O ii]λ3727 doublet, all from objects beyond the void. While no objects were within the void, these spectra show that the survey is capable of finding emission-line dwarfs in the void centers that are as faint as {M}r\\prime ˜ -12.4, should they be present. These spectra also show that redshifts estimated from our filtered images are accurate to several hundred km s-1 if the line is identified correctly, encouraging further work in finding ways to conduct redshift surveys through imaging alone.

  1. Herd-test-day variability of methane emissions predicted from milk MIR spectra in Holstein cows

    OpenAIRE

    Vanrobays, Marie-Laure; Kandel, Purna Bhadra; Soyeurt, Hélène; Vanlierde, Amélie; Dehareng, Frédéric; Froidmont, Eric; Pierre DARDENNE; Gengler, Nicolas

    2013-01-01

    The aim of this study was to estimate the herd-test-day (HTD) effect on milk yield, fat and protein content, and methane (CH4) emissions of Walloon Holstein first-parity cows. A total of 412,520 test-day records and milk mid-infrared (MIR) spectra of 69,223 cows in 1,104 herds were included in the data set. The prediction equation developed by Vanlierde et al. (Abstract submitted to EAAP 2013; R² of cross-validation=0.70) was applied on the recorded spectral data to predict CH4 emissions (g/d...

  2. Bound-bound transitions in the emission spectra of Ba$^{+}$--He excimer

    OpenAIRE

    Moroshkin, Peter; Kono, Kimitoshi

    2016-01-01

    We present an experimental and theoretical study of the emission and absorption spectra of the Ba$^{+}$ ions and Ba$^{+\\ast}$He excimer quasimolecules in the cryogenic Ba--He plasma. We observe several new spectral features in the emission spectrum which we assign to the electronic transitions between bound states of the excimer correlating to the 6$^{2}P_{3/2}$ and 5$^{2}D_{3/2,5/2}$ states of Ba$^{+}$. The resulting Ba$^{+}$(5$^{2}D_{J}$)He is a metastable electronically excited complex wit...

  3. Robust red-emission spectra and yields in firefly bioluminescence against temperature changes

    Science.gov (United States)

    Mochizuki, Toshimitsu; Wang, Yu; Hiyama, Miyabi; Akiyama, Hidefumi

    2014-05-01

    We measured the quantitative spectra of firefly (Photinus pyralis) bioluminescence at various temperatures to investigate the temperature dependence of the luciferin-luciferase reaction at 15-34 °C. The quantitative spectra were decomposed very well into red (1.9 eV), orange (2.0 eV), and green (2.2 eV) Gaussian components. The intensity of the green component was the only temperature sensitive quantity that linearly decreased as the temperature increased at pH 7 and 8. We found the quantitative bioluminescence spectra to be robust below 2.0 eV against temperature and other experimental conditions. The revealed robustness of the red emissions should be useful for quantitative applications such as adenosine-5'-triphosphate detection.

  4. Quantitative analysis of quantum dot dynamics and emission spectra in cavity quantum electrodynamics

    DEFF Research Database (Denmark)

    Madsen, Kristian Høeg; Lodahl, Peter

    2013-01-01

    We present detuning-dependent spectral and decay-rate measurements to study the difference between the spectral and dynamical properties of single quantum dots embedded in micropillar and photonic crystal cavities. For the micropillar cavity, the dynamics is well described by the dissipative Jaynes......–Cummings model, whereas systematic deviations are observed for the emission spectra. The discrepancy for the spectra is attributed to the coupling of other exciton lines to the cavity and interference of different propagation paths toward the detector of the fields emitted by the quantum dot. In contrast......, quantitative information about the system can readily be extracted from the dynamical measurements. In the case of photonic crystal cavities, we observe an anti-crossing in the spectra when detuning a single quantum dot through resonance, which is the spectral signature of a strong coupling. However, time...

  5. Genetic parameters for methane emissions predicted from milk mid-infrared spectra in dairy cows

    OpenAIRE

    Kandel, Purna Bhadra; Vanrobays, Marie-Laure; Vanlierde, Amélie; Dehareng, Frédéric; Froidmont, Eric; Pierre DARDENNE; Lewis, E.; Buckley, F.; Deighton, MH; McParland, S.; Gengler, Nicolas; Soyeurt, Hélène

    2013-01-01

    Genetic selection of low methane (CH4) emitting animals is additive and permanent but the difficulties associated with individual CH4 measurement result in a paucity of records required to estimate genetic variability of CH4 traits. Recently, it was shown that direct quantification of CH4 emissions by mid-infrared spectroscopy (MIR) from milk. The CH4 prediction equation was developed using 452 SF6 CH4 measurements with associated milk spectra and the calibration equation wa...

  6. Evidence for the Secondary Emission as the Origin of Hard Spectra in TeV Blazars

    CERN Document Server

    Zheng, Y G

    2016-01-01

    We develop a model for a possible origin of hard very high energy spectra from a distant blazar. In the model, both the primary photons produced in the source and secondary photons produced outside the source contribute to the observed high energy $\\gamma$-rays emission. That is, the primary photons are produced in the source through the synchrotron self-Compton (SSC) process, and the secondary photons are produced outside the source through high energy protons interaction with the background photons along the line of sight. We apply the model to a characteristic case was the very high energy (VHE) $\\gamma$-ray emissions in distant blazar 1ES 1101-232. Assuming a suitable electron and proton spectra, we obtain excellent fits to observed spectra of distant blazar 1ES 1101-232. This indicated that the surprisingly low attenuation of high energy $\\gamma$-rays, especially for the shape of the very high energy $\\gamma$-rays tail of the observed spectra, can be explained by secondary $\\gamma$-rays produced in inter...

  7. The Nuclear Region of Low Luminosity Flat Radio Spectrum Sources. II. Emission-Line Spectra

    CERN Document Server

    Gonçalves, A C

    2004-01-01

    We report on the spectroscopic study of 19 low luminosity Flat Radio Spectrum (LL FRS) sources selected from Marcha's et al. (1996) 200 mJy sample. In the optical, these objects are mainly dominated by the host galaxy starlight. After correcting the data for this effect, we obtain a new set of spectra clearly displaying weak emission lines; such features carry valuable information concerning the excitation mechanisms at work in the nuclear regions of LL FRS sources. We have used a special routine to model the spectra and assess the intensities and velocities of the emission lines; we have analyzed the results in terms of diagnostic diagrams. Our analysis shows that 79% of the studied objects harbour a Low Ionization Nuclear Emission-line Region (or LINER) whose contribution was swamped by the host galaxy starlight. The remaining objects display a higher ionization spectrum, more typical of Seyferts; due to the poor quality of the spectra, it was not possible to identify any possible large Balmer components. T...

  8. Sources of High-Energy Emission in the Green Pea Galaxies: New Constraints from Magellan Spectra

    Science.gov (United States)

    Carroll, Derek Alexander

    2016-01-01

    The recently discovered Green Pea galaxies display extreme starburst activity and may be some of the only possible Lyman continuum emitting galaxies at low redshift. Green Peas are characterized by their unusually high [O III]/[O II] ratios, similar to the ratios observed in high-redshift galaxies. In addition, the presence of the high-energy He II 4686 line shows that the Green Peas are highly ionized. However, the origin of the He II emission in the Green Peas, and many other starburst galaxies, is still an open question. We analyze IMACS and MagE spectra from the Magellan telescopes in order to evaluate the most probable cause of this He II emission. We also analyze other properties like dust content, temperature and density, and kinematic components. Our IMACS spectra show no Wolf-Rayet (WR) features. We set upper limits on the WR populations in our sample and conclude that Wolf-Rayet stars are not a likely candidate for the He II emission. With deeper MagE spectra we investigate energetic shocks as a possible source of the He II, and move one step closer to uncovering the origin of high-energy photons in these unique starbursts.

  9. VIRTIS on Venus Express thermal emission spectra near 1μm

    Science.gov (United States)

    Mueller, Nils; Tsang, Constantine; Helbert, Joern; Smrekar, Suzanne; Piccioni, Giuseppe; Drossart, Pierre

    2016-10-01

    Thermal emission from the surface of Venus is observable through narrow spectral windows close to 1μm. Surface temperature is strongly constrained by surface elevation, due to the thick and dense atmosphere. The data from Visible and InfraRed Thermal Imaging Spectrometer VIRTIS on Venus Express together with altimetry constrain surface emissivity. In VIRTIS observations at 1.02μm, strongly deformed highland plateaus (tesserae) appear to have a lower emissivity consistent with continental crust, an interpretation that implies existence of an early ocean. Comparison between the Magellan stereo digital elevation model (DEM) and altimetry shows that the altimetry height error in rough tesserae greatly exceeds the formal error. In the one tesserae outlier covered by altimetry, DEM, and VIRTIS, the height error could account for the observed emissivity variation. The radiances observed at 1.10 and 1.18μm have a different response to topography, mostly due to spectrally varying absorption in the overlying atmospheric column. Thus if the tesserae have the same emissivity as volcanic plains, its spectrum should be the same as that of plains of the correct surface elevation. In order to investigate this statistically, we create a database of all long exposure duration VIRTIS spectra in the range of 1 – 1.4μm. The spectra are corrected for the ubiquitous straylight from the dayside, based on analysis of spectra showing deep space. Because the 1.10 and 1.18μm peaks are narrow compared to the variation of instrument spectral registration, we fit each spectrum with a synthetic spectrum from an atmospheric radiative transfer model, using wavelength offset and bandwidths as parameters in addition to atmospheric variables. This dataset of ~28 million thermal emission spectra spans a wide range of southern latitudes and night local times, and thus may be useful for studies beyond the question of surface emissivity. A portion of this research was conducted at the Jet

  10. Lifetime-vibrational interference effects in resonantly excited x-ray emission spectra of CO

    Energy Technology Data Exchange (ETDEWEB)

    Skytt, P.; Glans, P.; Gunnelin, K. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    The parity selection rule for resonant X-ray emission as demonstrated for O{sub 2} and N{sub 2} can be seen as an effect of interference between coherently excited degenerate localized core states. One system where the core state degeneracy is not exact but somewhat lifted was previously studied at ALS, namely the resonant X-ray emission of amino-substituted benzene (aniline). It was shown that the X-ray fluorescence spectrum resulting from excitation of the C1s at the site of the {open_quotes}aminocarbon{close_quotes} could be described in a picture separating the excitation and the emission processes, whereas the spectrum corresponding to the quasi-degenerate carbons could not. Thus, in this case it was necessary to take interference effects between the quasi-degenerate intermediate core excited states into account in order to obtain agreement between calculations and experiment. The different vibrational levels of core excited states in molecules have energy splittings which are of the same order of magnitude as the natural lifetime broadening of core excitations in the soft X-ray range. Therefore, lifetime-vibrational interference effects are likely to appear and influence the band shapes in resonant X-ray emission spectra. Lifetime-vibrational interference has been studied in non-resonant X-ray emission, and in Auger spectra. In this report the authors discuss results of selectively excited soft X-ray fluorescence spectra of molecules, where they focus on lifetime-interference effects appearing in the band shapes.

  11. Emission lines between 1 and 2 keV in Cometary X-ray Spectra

    CERN Document Server

    Ewing, Ian; Bodewits, Dennis; Dennerl, Konrad; Lisse, Carey M; Wolk, Scott J

    2012-01-01

    We present the detection of new cometary X-ray emission lines in the 1.0 to 2.0 keV range using a sample of comets observed with the Chandra X-ray observatory and ACIS spectrometer. We have selected 5 comets from the Chandra sample with good signal-to-noise spectra. The surveyed comets are: C/1999 S4 (LINEAR), C/1999 T1 (McNaught-Hartley), 153P/2002 (Ikeya-Zhang), 2P/2003 (Encke), and C/2008 8P (Tuttle). We modeled the spectra with an extended version of our solar wind charge exchange (SWCX) emission model (Bodewits et al. 2007). Above 1 keV, we find Ikeya-Zhang to have strong emission lines at 1340 and 1850 eV that we identify as being created by solar wind charge exchange lines of Mg XI and Si XIII, respectively, and weaker emission lines at 1470, 1600, and 1950 eV formed by SWCX of Mg XII, Mg XI, and Si XIV, respectively. The Mg XI and XII and Si XIII and XIV lines are detected at a significant level for the other comets in our sample (LS4, MH, Encke, 8P), and these lines promise additional diagnostics to ...

  12. Observation of the Emission Spectra of an Atmospheric Pressure Radio-frequency Plasma Jet

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    An atmospheric pressure plasma jet (APPJ) using radio-frequency (13.56 MHz)power has been developed to produce homogeneous glow discharge at low temperature. With optical emission spectroscopy, we observed the excited species (atomic helium, atomic oxygen and metastable oxygen) generated in this APPJ and their dependence on gas composition ratio and RF power. O and O2(b1∑g+) are found in the effluent outside the jet by measuring the emission spectra of effluent perpendicular to the jet. An interesting phenomenon is found that there is an abnormal increase of O emission intensity (777.4 nm) between 10 mm and 40 mm away from the nozzle. This observation result is very helpful in practical operation.

  13. Gamma Emission Spectra from Neutron Resonances in 234,236,238U Measured Using the Dance Detector at Lansce

    Science.gov (United States)

    Ullmann, J. L.; Bredeweg, T. A.; Couture, A. J.; Haight, R. C.; Jandel, M.; Kawano, T.; Keksis, A. L.; O'Donnell, J. M.; Rundberg, R. S.; Vieira, D. J.; Wouters, J. M.; Wilhelmy, J. B.; Wu, C. Y.; Becker, J. A.; Chyzh, A.; Baramsai, B.; Mitchell, G. E.; Krticka, M.

    2013-03-01

    An accurate knowledge of the radiative strength function and level density is needed to calculate of neutron-capture cross sections. An additional constraint on these quantities is provided by measurements of γ-ray emission spectra following capture. We present γ-emission spectra from several neutron resonances in 234,236,238U, measured using the DANCE detector at LANSCE. The measurements are compared to preliminary calculations of the cascade. It is observed that the generalized Lorentzian form of the E1 strength function cannot reproduce the shape of the emission spectra, but a better description is made by adding low-lying M1 Lorentzian strength.

  14. Constraining hot Jupiter’s atmospheric structure and dynamics through Doppler shifted emission spectra

    Science.gov (United States)

    Zhang, Jisheng; Kempton, Eliza; Rauscher, Emily

    2017-01-01

    In recent years, astronomers have begun successfully observing the atmospheres of extrasolar planets using ground-based telescopes equipped with spectrographs capable of observing at high spectral resolution (R~105). Such studies are capable of diagnosing the atmospheric structure, composition, and dynamics (winds and rotation) of both transiting and non-transiting exoplanets. However, few studies have examined how the 3-D atmospheric dynamics could alter the emitted light of hot Jupiters at such high spectral resolution. Here, we present a model to explore such influence on the hot Jupiters’ thermal emission spectra. Our aim is to investigate the extent to which the effects of 3-D atmospheric dynamics are imprinted on planet-averaged thermal emission spectra. We couple together a 3-D general circulation model of hot Jupiter atmospheric dynamics (Rauscher & Menou, 2012) with a radiative transfer solver to predict the planet’s disk-integrated emission spectrum as a function of its orbital phase. For the first time, we self-consistently include the effects of the line-of-sight atmospheric motions (resulting from winds and rotation) in the calculation to produce Doppler-shifted spectral line profiles that result from the atmospheric dynamics. We focus our study on three benchmark hot Jupiters, HD 189733b, HD 209458b, and WASP-43b which have been the focus of previous detailed observational studies. We find that the high-resolution Doppler shifted thermal emission spectra can be used to diagnose key properties of the dynamical atmosphere - the planet’s longitudinal temperature and wind structure, and its rotation rate.

  15. Method of fission product beta spectra measurements for predicting reactor anti-neutrino emission

    Energy Technology Data Exchange (ETDEWEB)

    Asner, D.M.; Burns, K.; Campbell, L.W.; Greenfield, B.; Kos, M.S., E-mail: markskos@gmail.com; Orrell, J.L.; Schram, M.; VanDevender, B.; Wood, L.S.; Wootan, D.W.

    2015-03-11

    The nuclear fission process that occurs in the core of nuclear reactors results in unstable, neutron-rich fission products that subsequently beta decay and emit electron antineutrinos. These reactor neutrinos have served neutrino physics research from the initial discovery of the neutrino to today's precision measurements of neutrino mixing angles. The prediction of the absolute flux and energy spectrum of the emitted reactor neutrinos hinges upon a series of seminal papers based on measurements performed in the 1970s and 1980s. The steadily improving reactor neutrino measurement techniques and recent reconsiderations of the agreement between the predicted and observed reactor neutrino flux motivates revisiting the underlying beta spectra measurements. A method is proposed to use an accelerator proton beam delivered to an engineered target to yield a neutron field tailored to reproduce the neutron energy spectrum present in the core of an operating nuclear reactor. Foils of the primary reactor fissionable isotopes placed in this tailored neutron flux will ultimately emit beta particles from the resultant fission products. Measurement of these beta particles in a time projection chamber with a perpendicular magnetic field provides a distinctive set of systematic considerations for comparison to the original seminal beta spectra measurements. Ancillary measurements such as gamma-ray emission and post-irradiation radiochemical analysis will further constrain the absolute normalization of beta emissions per fission. The requirements for unfolding the beta spectra measured with this method into a predicted reactor neutrino spectrum are explored.

  16. Method of fission product beta spectra measurements for predicting reactor anti-neutrino emission

    Energy Technology Data Exchange (ETDEWEB)

    Asner, David M.; Burns, Kimberly A.; Campbell, Luke W.; Greenfield, Bryce A.; Kos, Marek S.; Orrell, John L.; Schram, Malachi; VanDevender, Brent A.; Wood, Lynn S.; Wootan, David W.

    2015-03-01

    The nuclear fission process that occurs in the core of nuclear reactors results in unstable, neutron-rich fission products that subsequently beta decay and emit electron antineutrinos. These reactor neutrinos have served neutrino physics research from the initial discovery of the neutrino to today's precision measurements of neutrino mixing angles. The prediction of the absolute flux and energy spectrum of the emitted reactor neutrinos hinges upon a series of seminal papers based on measurements performed in the 1970s and 1980s. The steadily improving reactor neutrino measurement techniques and recent reconsiderations of the agreement between the predicted and observed reactor neutrino flux motivates revisiting the underlying beta spectra measurements. A method is proposed to use an accelerator proton beam delivered to an engineered target to yield a neutron field tailored to reproduce the neutron energy spectrum present in the core of an operating nuclear reactor. Foils of the primary reactor fissionable isotopes placed in this tailored neutron flux will ultimately emit beta particles from the resultant fission products. Measurement of these beta particles in a time projection chamber with a perpendicular magnetic field provides a distinctive set of systematic considerations for comparison to the original seminal beta spectra measurements. Ancillary measurements such as gamma-ray emission and post-irradiation radiochemical analysis will further constrain the absolute normalization of beta emissions per fission. The requirements for unfolding the beta spectra measured with this method into a predicted reactor neutrino spectrum are explored.

  17. Emission spectra of photoionized plasmas induced by intense EUV pulses: Experimental and theoretical investigations

    Science.gov (United States)

    Saber, Ismail; Bartnik, Andrzej; Skrzeczanowski, Wojciech; Wachulak, Przemysław; Jarocki, Roman; Fiedorowicz, Henryk

    2017-03-01

    Experimental measurements and numerical modeling of emission spectra in photoionized plasma in the ultraviolet and visible light (UV/Vis) range for noble gases have been investigated. The photoionized plasmas were created using laser-produced plasma (LPP) extreme ultraviolet (EUV) source. The source was based on a gas puff target; irradiated with 10ns/10J/10Hz Nd:YAG laser. The EUV radiation pulses were collected and focused using grazing incidence multifoil EUV collector. The laser pulses were focused on a gas stream, injected into a vacuum chamber synchronously with the EUV pulses. Irradiation of gases resulted in a formation of low temperature photoionized plasmas emitting radiation in the UV/Vis spectral range. Atomic photoionized plasmas produced this way consisted of atomic and ionic with various ionization states. The most dominated observed spectral lines originated from radiative transitions in singly charged ions. To assist in a theoretical interpretation of the measured spectra, an atomic code based on Cowan's programs and a collisional-radiative PrismSPECT code have been used to calculate the theoretical spectra. A comparison of the calculated spectral lines with experimentally obtained results is presented. Electron temperature in plasma is estimated using the Boltzmann plot method, by an assumption that a local thermodynamic equilibrium (LTE) condition in the plasma is validated in the first few ionization states. A brief discussion for the measured and computed spectra is given.

  18. Emission Spectra of Working Mixtures of a HgBr/HgCl Excimer Lamp

    Science.gov (United States)

    Malinin, A. N.; Guĭvan, N. N.; Shimon, L. L.

    2000-12-01

    A study of emission spectra of a gas-discharge plasma produced in a HgBr/HgCl excimer lamp, which is filled with multicomponent working mixtures at atmospheric pressure (HgBr2 and HgCl2 with additions of molecular nitrogen and xenon), are reported. A gas-discharge plasma was produced by high-frequency (pulses ˜100 ns long with a repetition rate of up to 2000 Hz) barrier and surface discharges, which took place simultaneously. Emission of HgBr* and HgCl* excimer molecules, the second positive system of molecular oxygen, and helium and xenon lines in the UV, visible, and IR spectral regions was observed. The strongest emission of HgBr* and HgCl* molecules (the emission intensities were in the ratio 10:1) was observed in the HgBr2: HgCl2: N2: He mixture. Regularities in spectral and integrated characteristics of gas-discharge plasma emission are discussed.

  19. Mid-infrared spectra of PAH emission in Herbig AeBe stars

    CERN Document Server

    Sloan, G C; Forrest, W J; Leibensperger, E; Sargent, B; Li, A; Najita, J; Watson, D M; Brandl, B R; Chen, C H; Green, J D; Markwick-Kemper, F; Herter, T L; D'Alessio, P; Morris, P W; Barry, J; Hall, P; Myers, P C; Houck, J R

    2005-01-01

    We present spectra of four Herbig AeBe stars obtained with the Infrared Spectrograph (IRS). on the Spitzer Space Telescope. All four of the sources show strong emission from polycyclic aromatic hydrocarbons (PAHs), with the 6.2 um emission feature shifted to 6.3 um and the strongest C-C skeletal-mode feature occuring at 7.9 um instead of at 7.7 um as is often seen. Remarkably, none of the four stars have silicate emission. The strength of the 7.9 um feature varies with respect to the 11.3 um feature among the sources, indicating that we have observed PAHs with a range of ionization fractions. The ionization fraction is higher for systems with hotter and brighter central stars. Two sources, HD 34282 and HD 169142, show emission features from aliphatic hydrocarbons at 6.85 and 7.25 um. The spectrum of HD 141569 shows a previously undetected emission feature at 12.4 um which may be related to the 12.7 um PAH feature. The spectrum of HD 135344, the coolest star in our sample, shows an unusual profile in the 7-9 u...

  20. Bayesian electron density inference from JET lithium beam emission spectra using Gaussian processes

    CERN Document Server

    Kwak, Sehyun; Brix, M; Ghim, Y -c

    2016-01-01

    A Bayesian model to infer edge electron density profiles is developed for the JET lithium beam emission spectroscopy system, measuring Li I line radiation using 26 channels with ~1 cm spatial resolution and 10~20 ms temporal resolution. The density profile is modelled using a Gaussian process prior, and the uncertainty of the density profile is calculated by a Markov Chain Monte Carlo (MCMC) scheme. From the spectra measured by the transmission grating spectrometer, the Li line intensities are extracted, and modelled as a function of the plasma density by a multi-state model which describes the relevant processes between neutral lithium beam atoms and plasma particles. The spectral model fully takes into account interference filter and instrument effects, that are separately estimated, again using Gaussian processes. The line intensities are inferred based on a spectral model consistent with the measured spectra within their uncertainties, which includes photon statistics and electronic noise. Our newly devel...

  1. The Impact of Non-Uniform Thermal Structure on the Interpretation of Exoplanet Emission Spectra

    CERN Document Server

    Feng, Y Katherina; Fortney, Jonathan J; Stevenson, Kevin B; Bean, Jacob; Kreidberg, Laura; Parmentier, Vivien

    2016-01-01

    The determination of atmospheric structure and molecular abundances of planetary atmospheres via spectroscopy involves direct comparisons between models and data. While varying in sophistication, most model-spectra comparisons fundamentally assume "1D" model physics. However, knowledge from general circulation models and of solar system planets suggests that planetary atmospheres are inherently "3D" in their structure and composition. We explore the potential biases resulting from standard "1D" assumptions within a Bayesian atmospheric retrieval framework. Specifically, we show how the assumption of a single 1-dimensional thermal profile can bias our interpretation of the thermal emission spectrum of a hot Jupiter atmosphere that is composed of two thermal profiles. We retrieve upon spectra of unresolved model planets as observed with a combination of $HST$ WFC3+$Spitzer$ IRAC as well as $JWST$ under varying differences in the two thermal profiles. For WFC3+IRAC, there is a significantly biased estimate of CH...

  2. Identifying Student and Teacher Difficulties in Interpreting Atomic Spectra Using a Quantum Model of Emission and Absorption of Radiation

    Science.gov (United States)

    Savall-Alemany, Francisco; Domènech-Blanco, Josep Lluís; Guisasola, Jenaro; Martínez-Torregrosa, Joaquín

    2016-01-01

    Our study sets out to identify the difficulties that high school students, teachers, and university students encounter when trying to explain atomic spectra. To do so, we identify the key concepts that any quantum model for the emission and absorption of electromagnetic radiation must include to account for the gas spectra and we then design two…

  3. t-SURFF: Fully Differential Two-Electron Photo-Emission Spectra

    CERN Document Server

    Scrinzi, Armin

    2012-01-01

    The time dependent surface flux (t-SURFF) method is extended to single and double ionization of two electron systems. Fully differential double emission spectra by strong pulses at extreme UV and infrared wave length are calculated using simulation volumes that only accommodate the effective range of the atomic binding potential and the quiver radius of free electrons in the external field. For a model system we find pronounced dependence of shake-up and non-sequential double ionization on phase and duration of the laser pulse. Extension to fully three-dimensional calculations is discussed.

  4. Calcium Pyroxenes at Mercurian Surface Temperatures: Investigation of In-Situ Emissivity Spectra.

    Science.gov (United States)

    Ferrari, Sabrina; Maturilli, Alessandro; Helbert, Jörn; Rossi, Manuela; Nestola, Fabrizio; D'Amore, Mario; Hiesinger, Harald

    2014-05-01

    Several observations point to the possibility that Ca-rich (and low-Fe) clinopyroxenes could be common constituent minerals of the surface of Mercury. The upcoming ESA-JAXA BepiColombo mission to Mercury will carry on board the Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) that will provide surface emissivity spectra in the wavelength range from 7-14 μm. This spectral range is very useful to identify the fine-scale structural properties of several silicates including pyroxenes. The extreme daily surface temperature range of Mercury (70 to 725 K) that significantly affects the spectral signature of minerals will make the interpretation of MERTIS observations challenging. It has been shown that spectra of clinopyroxenes with similar calcium content display a deepening of the main absorption bands, and a shift of the band minima toward higher wavelengths with increasing temperatures. Similar shifts can also be observed at constant temperature with increasing iron content in the M2 site. Therefore, the thermal expansion induced by the increasing temperature simulates the presence of a larger cation (e.g., iron vs. magnesium) within the mineral structure. Interestingly, each band shifts by a different amount, representing a marker for the real chemistry of the sample. A detailed study of the described mineral behavior is fundamental to localize those spectral bands sensitive to the daily temperature range of the Mercury surface. In combination with the temperature measurements obtained independently by the radiometer channel of MERTIS this will help to further constrain the mineralogical interpretation of the MERTIS spectral data. Here we present high-temperature (up to 750 K) laboratory emissivity spectra of several augitic pyroxenes with different calcium contents and very different magnesium to iron ratios. The spectra were derived from individual well-preserved natural crystals of several pyroxenes of less than 125 ?m in size, which approaches the

  5. Effects of high pressure on the Raman and fluorescence emission spectra of two novel 1,3,4-oxadiazole derivatives

    Institute of Scientific and Technical Information of China (English)

    Luo Ji-Feng; Tang Ben-Chen; Gao Chun-Xiao; Li Min; Han Yong-Hao; Zou Guang-Tian

    2005-01-01

    The effects of pressure on the fluorescence emission and Raman spectra of 1,4-bis[(4-methyloxyphenyl)-1,3,4-oxadiazolyl]- 2,5-bisheptyloxyphenylene (OXD-2) and on the fluorescence emission spectra of 1,4-bis[(4-methylphenyl)-1,3,4-oxadiazolyl]phenylene (OXD-1) are investigated using a diamond anvil cell. With the increase of pressure, the intensity of the fluorescence emission increases and reaches maxima at 13GPa for OXD-1 and at 9.6GPa for OXD-2.The effect of pressure on the peak position of the emission shows a similar trend, red shift with the increase of pressure.But at higher pressures, the intensity of emission drops down dramatically. The Raman spectra of OXD-2 indicate that there appears a structural change at ca 3GPa.

  6. TDDFT Study of the Electronic Structure, Absorption and Emission Spectra of the Light Emitters of the Amazing Firefly Bioluminescence and Solvation Effects on the Spectra

    Institute of Scientific and Technical Information of China (English)

    REN,Ai-Min; GUO,Jing-Fu; FENG,Ji-Kang; ZOU,Lu-Yi; LI,Zhong-Wei; GODDARD,John,David

    2008-01-01

    The ground and excited state properties of luciferin (LH2) and oxyluciferin (OxyLH2), the bioluminescent chemicals in the firefly, have been characterized using density functional theory (DFT) and time dependent DFT (TDDFT) methods. The effects of solvation on the electronic absorption and emission spectra of luciferin and oxyluciferin were predicted with a self-consistent isodensity polarized continuum model of the solvent using TDDFT.The S0→S1 vertical excitation energies in the gas phase and in water were obtained. Optimizations of the excited state geometries permitted the first predictions of the fluorescence spectra for these biologically important molecules. Shifts in both of the absorption and emission spectra on proceeding from the gas phase to aqueous solution were also predicted.

  7. K-Alpha Emission Spectra From Non-Equilibrium Ionizing Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, V L; Decaux, V; Beiersdorfer, P

    2004-12-16

    K{alpha} X-ray emission spectra from highly charged Fe ions have been theoretically predicted using a detailed and systematic spectral model. Account has been taken of the fundamental atomic radiative-emission processes associated with inner-shell electron collisional excitation and ionization, as well as dielectronic recombination. Particular emphasis has been directed at extreme non-equilibrium or transient-ionization conditions, which can occur in astrophysical and tokamak plasmas. Good agreement has been found in comparisons with spectral observations on the EBIT-II electron beam ion trap at the Lawrence Livermore National Laboratory. We have identified spectral features that can serve as diagnostics of the electron density, the line-formation mechanism, and the charge-state distribution.

  8. Temperature dependence of the emission spectra of individual self-assembled quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Zora, A; Simserides, C; Triberis, G P, E-mail: azora@phys.uoa.g [University of Athens, Physics Department, Panepistimiopolis, Zografos, GR-15784, Athens (Greece)

    2010-09-01

    We have developed a quantum-mechanical theory for the interaction of light and electron-hole excitations in semiconductor quantum dots. Our theoretical analysis results in an expression for the photoluminescence intensity in the non-linear regime. The validity of the theoretical results is tested analyzing experimental data reported for the temperature dependence of the emission spectra of an individual lens-shaped In{sub 0.4}Ga{sub 0.6}As self-assembled quantum dot in a wide temperature range up to 300 K. Our theoretical predictions for the redshift of the emission peak with increasing temperature, in the range 2-300 K, agree with the experiment.

  9. Bound-bound transitions in the emission spectra of Ba$^{+}$--He excimer

    CERN Document Server

    Moroshkin, Peter

    2016-01-01

    We present an experimental and theoretical study of the emission and absorption spectra of the Ba$^{+}$ ions and Ba$^{+\\ast}$He excimer quasimolecules in the cryogenic Ba--He plasma. We observe several new spectral features in the emission spectrum which we assign to the electronic transitions between bound states of the excimer correlating to the 6$^{2}P_{3/2}$ and 5$^{2}D_{3/2,5/2}$ states of Ba$^{+}$. The resulting Ba$^{+}$(5$^{2}D_{J}$)He is a metastable electronically excited complex with orbital angular momentum $L$=2, thus expanding the family of known metal--helium quasimolecules. It might be suitable for high-resolution spectroscopic studies and for the search for new polyatomic exciplex structures.

  10. Bound-bound transitions in the emission spectra of Ba+-He excimer

    Science.gov (United States)

    Moroshkin, P.; Kono, K.

    2016-05-01

    We present an experimental and theoretical study of the emission and absorption spectra of the Ba+ ions and Ba+*He excimer quasimolecules in the cryogenic Ba-He plasma. We observe several spectral features in the emission spectrum, which we assign to the electronic transitions between bound states of the excimer correlating to the 6 2P3 /2 and 5 2D3 /2 ,5 /2 states of Ba+. The resulting Ba+(5 2DJ) He is a metastable electronically excited complex with orbital angular momentum L =2 , thus expanding the family of known metal-helium quasimolecules. It might be suitable for high-resolution spectroscopic studies and for the search for new polyatomic exciplex structures.

  11. Determination of thermal emission spectra maximizing thermophotovoltaic performance using a genetic algorithm

    CERN Document Server

    DeSutter, John; Francoeur, Mathieu

    2016-01-01

    Optimal radiator thermal emission spectra maximizing thermophotovoltaic (TPV) conversion efficiency and output power density are determined when temperature effects in the cell are considered. To do this, a framework is designed in which a TPV model that accounts for radiative, electrical and thermal losses is coupled with a genetic algorithm. The TPV device under study involves a spectrally selective radiator at a temperature of 2000 K, a gallium antimonide cell, and a cell thermal management system characterized by a fluid temperature and a heat transfer coefficient of 293 K and 600 Wm-2K-1. It is shown that a maximum conversion efficiency of 38.8% is achievable with an emission spectrum that has emissivity of unity between 0.719 eV and 0.763 eV and zero elsewhere. This optimal spectrum is less than half of the width of those when thermal losses are neglected. A maximum output power density of 41708 Wm-2 is achievable with a spectrum having emissivity values of unity between 0.684 eV and 1.082 eV and zero e...

  12. Random mixtures of polycyclic aromatic hydrocarbon spectra match interstellar infrared emission

    CERN Document Server

    Rosenberg, Marissa J F; Boersma, Christiaan

    2014-01-01

    The mid-infrared (IR; 5-15~$\\mu$m) spectrum of a wide variety of astronomical objects exhibits a set of broad emission features at 6.2, 7.7, 8.6, 11.3 and 12.7 $\\mu$m. About 30 years ago it was proposed that these signatures are due to emission from a family of UV heated nanometer-sized carbonaceous molecules known as polycyclic aromatic hydrocarbons (PAHs), causing them to be referred to as aromatic IR bands (AIBs). Today, the acceptance of the PAH model is far from settled, as the identification of a single PAH in space has not yet been successful and physically relevant theoretical models involving ``true'' PAH cross sections do not reproduce the AIBs in detail. In this paper, we use the NASA Ames PAH IR Spectroscopic Database, which contains over 500 quantum-computed spectra, in conjunction with a simple emission model, to show that the spectrum produced by any random mixture of at least 30 PAHs converges to the same 'kernel'-spectrum. This kernel-spectrum captures the essence of the PAH emission spectrum...

  13. Theoretical simulations of emission spectra of Fe7+ and Fe8+

    Institute of Scientific and Technical Information of China (English)

    Zeng Jiao-Long; Wang Yan-Gui; Zhao Gang; Yuan Jian-Min

    2006-01-01

    The energy levels, oscillator strengths, spontaneous radiative decay rates, and electron impact collision strengths are calculated for Fe Ⅷ and Fe Ⅸ using the recently developed flexible atomic code (FA3. These atomic data are used to analyse the emission spectra of both laboratory and astrophysical plasmas. The nf-3d emission lines have been simulated for Fe Ⅷ and Fe Ⅸ in a wavelength range of 6-14 nm. For Fe Ⅷ, the predicted relative intensities of lines are insensitive to temperature. For Fe Ⅸ, however, the intensity ratios are very sensitive to temperature, implying that the information of temperature in the experiment can be inferred. Detailed line analyses have also been carried out in a wavelength range of 60-80 nm for Fe Ⅷ, where the solar ultraviolet measurements of emitted radiation spectrometer records a large number of spectra. More lines can be identified with the aid of present atomic data. A complete dataset is available electronically from http://www.astrnomy.csdb.cn/EIE/.

  14. Correction of emission spectra in microspectrofluorimetry using a reference lamp: computations.

    Science.gov (United States)

    Galassi, L

    1992-01-01

    Accurate correction of emission spectra in microspectrofluorimetry, using a reference lamp, may require that a factor for the emissivity of tungsten be introduced. This is only possible provided that the true temperature of the lamp filament is known. A method is given for obtaining the true temperature from the knowledge of the colour temperature. Also, the values of the spectral concentration of the radiance of the black body, either computed according to Planck's equation or taken from available published tables, have to be converted from energetic units to units of quanta since the photomultiplier is linear not to absorbed power but to units of quanta. When the fluorescence spectra to be corrected extend into the far red it is preferable to use a lower temperature (by lowering the supply voltage) than that for which the lamp is certified. It is possible to determine the new temperature (and then the corresponding spectral distribution) by taking a few pairs of measurements at different wavelengths both at the lower voltage and at the voltage for which the lamp is certified and then introducing these values in a non-linear regression soluble on a PC with a curve fitting program. The microscope tungsten halogen lamp can conveniently be used as a reference, thanks to its small size and its steady spectral characteristics. When high accuracy is required, however, the halogen lamp should be calibrated against a certified ribbon filament lamp.

  15. Thermal Infrared Emission Spectra of Terrestrial Exoplanets Influenced by Multi-layer Clouds

    Science.gov (United States)

    Schreier, Franz; Vasquez, Mayte; Gimeno Garcia, Sebastian; Kitzmann, Daniel

    2016-04-01

    Clouds play an important role in the radiative transfer of planetary atmospheres: they are key elements of the climate system and influence the planet's spectral appearance. Given the thousands of exoplanets discovered so far, including some dozens of Earth-sized exoplanets, the feasibility of remote sensing of exoplanet atmospheres is attracting increasing attention. Here we present a study of the thermal emission of cloud-covered Earth-like exoplanets orbiting in the habitable zone of F, G, K, and M-type stars. A line-by-line model for molecular absorption has been coupled to a discrete ordinate multiple scattering radiative transfer solver. Pressure, temperature, and molecular concentration profiles were taken from a consistent radiative-convective climate model including a parameterized cloud description (Kitzmann et al., A&A, 2010). The main focus of the current work is the impact of multi-layer clouds on emission spectra in the thermal infrared. The effects of low-level water clouds and high level ice clouds simultaneously on signatures of H2O, CO2, O3, etc will be studied for various resolutions. Furthermore, comparisons with spectra resulting from a low-resolution code will be shown.

  16. M-type asteroids in the mid-infrared: thermal inertias and emissivity spectra

    Science.gov (United States)

    Landsman, Zoe A.; Emery, Joshua P.; Campins, Humberto

    2016-10-01

    The M-type asteroid taxon has been inferred to contain metallic asteroids. This inference comes mainly from spectral analogy to iron meteorites and from the observation of high radar albedos among M-types. There is, nevertheless, evidence for significant compositional diversity within the M-type population. Spectral signatures of both high-temperature silicates (λ~0.9 μm) and hydrated minerals (λ~3 μm) are common in this group. The nature of the M-types is, therefore, still not well understood. In order to further test the hypothesis that many M-types are metallic, we have undertaken an observational study at mid-infrared wavelengths (5.2 – 38 μm). Our aim is to characterize the silicate composition and the thermal properties of a sample of M-type asteroids. If metallic, we expect relatively high thermal inertia and an absence of silicate emissivity features. The spectra we analyze were measured with the InfraRed Spectrograph (IRS) on the Spitzer Space Telescope. We present emissivity spectra and the initial results of thermophysical modeling, including derived thermal inertias. We chose our sample because these asteroids have also been observed at complementary wavelengths, such as visible, near-infrared and radar, which places further constraints on the interpretation of our results.

  17. Modeling of aircraft exhaust emissions and infrared spectra for remote measurement of nitrogen oxides

    Directory of Open Access Journals (Sweden)

    K. Beier

    Full Text Available Infrared (IR molecular spectroscopy is proposed to perform remote measurements of NOx concentrations in the exhaust plume and wake of aircraft. The computer model NIRATAM is applied to simulate the physical and chemical properties of the exhaust plume and to generate low resolution IR spectra and synthetical thermal images of the aircraft in its natural surroundings. High-resolution IR spectra of the plume, including atmospheric absorption and emission, are simulated using the molecular line-by-line radiation model FASCODE2. Simulated IR spectra of a Boeing 747-400 at cruising altitude for different axial and radial positions in the jet region of the exhaust plume are presented. A number of spectral lines of NO can be identified that can be discriminated from lines of other exhaust gases and the natural atmospheric background in the region around 5.2 µm. These lines can be used to determine NO concentration profiles in the plume. The possibility of measuring nitrogen dioxide NO2 is also discussed briefly, although measurements turn out to be substantially less likely than those of NO. This feasibility study compiles fundamental data for the optical and radiometric design of an airborne Fourier transform spectrometer and the preparation of in-flight measurements for monitoring of aircraft pollutants.

  18. Evaluation of potential emission spectra for the reliable classification of fluorescently coded materials

    Science.gov (United States)

    Brunner, Siegfried; Kargel, Christian

    2011-06-01

    The conservation and efficient use of natural and especially strategic resources like oil and water have become global issues, which increasingly initiate environmental and political activities for comprehensive recycling programs. To effectively reutilize oil-based materials necessary in many industrial fields (e.g. chemical and pharmaceutical industry, automotive, packaging), appropriate methods for a fast and highly reliable automated material identification are required. One non-contacting, color- and shape-independent new technique that eliminates the shortcomings of existing methods is to label materials like plastics with certain combinations of fluorescent markers ("optical codes", "optical fingerprints") incorporated during manufacture. Since time-resolved measurements are complex (and expensive), fluorescent markers must be designed that possess unique spectral signatures. The number of identifiable materials increases with the number of fluorescent markers that can be reliably distinguished within the limited wavelength band available. In this article we shall investigate the reliable detection and classification of fluorescent markers with specific fluorescence emission spectra. These simulated spectra are modeled based on realistic fluorescence spectra acquired from material samples using a modern VNIR spectral imaging system. In order to maximize the number of materials that can be reliably identified, we evaluate the performance of 8 classification algorithms based on different spectral similarity measures. The results help guide the design of appropriate fluorescent markers, optical sensors and the overall measurement system.

  19. Measuring nickel masses in Type Ia supernovae using cobalt emission in nebular phase spectra

    CERN Document Server

    Childress, Michael J; Seitenzahl, Ivo; Sullivan, Mark; Maguire, Kate; Taubenberger, Stefan; Scalzo, Richard; Ruiter, Ashley; Blagorodnova, Nadejda; Camacho, Yssavo; Castillo, Jayden; Elias-Rosa, Nancy; Fraser, Morgan; Gal-Yam, Avishay; Graham, Melissa; Howell, D Andrew; Inserra, Cosimo; Jha, Saurabh W; Kumar, Sahana; Mazzali, Paolo A; McCully, Curtis; Morales-Garoffolo, Antonia; Pandya, Viraj; Polshaw, Joe; Schmidt, Brian; Smartt, Stephen; Smith, Ken W; Sollerman, Jesper; Spyromilio, Jason; Tucker, Brad; Valenti, Stefano; Walton, Nicholas; Wolf, Christian; Yaron, Ofer; Young, D R; Yuan, Fang; Zhang, Bonnie

    2015-01-01

    The light curves of Type Ia supernovae (SNe Ia) are powered by the radioactive decay of $^{56}$Ni to $^{56}$Co at early times, and the decay of $^{56}$Co to $^{56}$Fe from ~60 days after explosion. We examine the evolution of the [Co III] 5892 A emission complex during the nebular phase for SNe Ia with multiple nebular spectra and show that the line flux follows the square of the mass of $^{56}$Co as a function of time. This result indicates both efficient local energy deposition from positrons produced in $^{56}$Co decay, and long-term stability of the ionization state of the nebula. We compile 77 nebular spectra of 25 SN Ia from the literature and present 17 new nebular spectra of 7 SNe Ia, including SN2014J. From these we measure the flux in the [Co III] 5892 A line and remove its well-behaved time dependence to infer the initial mass of $^{56}$Ni ($M_{Ni}$) produced in the explosion. We then examine $^{56}$Ni yields for different SN Ia ejected masses ($M_{ej}$ - calculated using the relation between light...

  20. Modeling of the EUV and X-Ray Emission Spectra Induced by the Solar Winds Ions in the Heliosphere

    Science.gov (United States)

    Kharchenko, Vasili

    2005-01-01

    We have carried out investigation of the EUV and X-ray emission spectra induced in interaction between the Solar Wind (SW) and interstellar neutral gas. The spectra of most important SW ions have been computed for the charge-exchange mechanism of X-ray emission using new accurate spectroscopic data from recent laboratory measurements and theoretical calculations. Total spectra have been constructed as a sum of spectra induced in the charge-exchange collisions by individual O(exp q+), C(exp q+), N(exp q+), Ne(exp q+), Mg (exp q+) and Fe(exp q+) ions. Calculations have been performed for X-ray emission from the heliospheric hydrogen and helium gas. X-ray maps of the heliosphere have been computed. The power density of X-ray sources in the heliospheric ecliptic plane is shown for the H gas and for the He gas. Distances from the Sun (0,0) are given in AU. The helium cone is clear seen in the X-ray map of the charge-exchange emission induced by the solar wind. X-ray emission spectra detected by the Chandra X-ray telescope from the "dark" side of Moon has been identified as a X-ray background emission induced by the solar wind from the geocorona. Spectra and intensities of this charge-exchange X-rays have been compared with the heliospheric component of the X-ray background. Observations and modeling of the SW spectra induced from the geocorona indicate a strong presence of emission lines of highly charged oxygen ions. Anisotropy in distribution of heliospheric X-rays has been predicted and calculated for the regions of the fast and slow solar winds.

  1. Modeling the Emission Spectra of Organic Molecules: A Competition between Franck-Condon and Nuclear Ensemble Methods.

    Science.gov (United States)

    de Sousa, Leonardo Evaristo; Ribeiro, Luiz Antonio; Fonseca, Antonio Luciano de Almeida; da Silva Filho, Demétrio Antonio

    2016-07-14

    The emission spectra of flexible and rigid organic molecules are theoretically investigated in the framework of the Franck-Condon (FC) and nuclear ensemble (NE) approaches, both of which rely on results from density functional theory but differ in the way vibrational contributions are taken into account. Our findings show that the emission spectra obtained using the NE approach are in better agreement with experiment than the ones produced by FC calculations considering both rigid and flexible molecules. Surprisingly, the description of a suitable balance between the vibronic progression and the emission spectra envelope shows dependency on the initial sampling for the NE calculations which must be judiciously selected. Our results intend to provide guidance for a better theoretical description of light emission properties of organic molecules with applications in organic electronic devices.

  2. Consistency of atomic data for the interpretation of beam emission spectra

    Energy Technology Data Exchange (ETDEWEB)

    Delabie, E; Von Hellermann, M G [FOM Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Brix, M; Giroud, C; Surrey, E; Zastrow, K D [EURATOM/CCFE Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Jaspers, R J E [Eindhoven University of Technology, Postbus 513, 5600 MB Eindhoven (Netherlands); Marchuk, O [Forschungszentrum Juelich, Association EURATOM-FZJ, 52425, Juelich (Germany); O' Mullane, M G [Department of Physics, University of Strathclyde, 107 Rottenrow, Glasgow G4 0NG (United Kingdom); Ralchenko, Yu, E-mail: e.delabie@fz-juelich.d [Atomic Physics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8422 (United States)

    2010-12-15

    Several collisional-radiative (CR) models (Anderson et al 2000 Plasma Phys. Control. Fusion 42 781-806, Hutchinson 2002 Plasma Phys. Control. Fusion 44 71-82, Marchuk et al 2008 Rev. Sci. Instrum. 79 10F532) have been developed to calculate the attenuation and the population of excited states of hydrogen or deuterium beams injected into tokamak plasmas. The datasets generated by these CR models are needed for the modelling of beam ion deposition and (excited) beam densities in current experiments, and the reliability of these data will be crucial to obtain helium ash densities on ITER combining charge exchange and beam emission spectroscopy. Good agreement between the different CR models for the neutral beam (NB) is found, if corrections to the fundamental cross sections are taken into account. First the H{sub {alpha}} and H{sub {beta}} beam emission spectra from JET are compared with the expected intensities. Second, the line ratios within the Stark multiplet are compared with the predictions of a sublevel resolved model. The measured intensity of the full multiplet is {approx}30% lower than expected on the basis of beam attenuation codes and the updated beam emission rates, but apart from the atomic data this could also be due to the characterization of the NB path and line of sight integration and the absolute calibration of the optics. The modelled n = 3 to n = 4 population agrees very well with the ratio of the measured H{sub {alpha}} to H{sub {beta}} beam emission intensities. Good agreement is found as well between the NB power fractions measured with beam emission in plasma and on the JET Neutral Beam Test Bed. The Stark line ratios and {sigma}/{pi} intensity ratio deviate from a statistical distribution, in agreement with the CR model in parabolic states from Marchuk et al (2010 J. Phys. B: At. Mol. Opt. Phys. 43 011002).

  3. The Slowly Varying Corona. I. Daily Differential Emission Measure Distributions Derived from EVE Spectra

    Science.gov (United States)

    Schonfeld, S. J.; White, S. M.; Hock-Mysliwiec, R. A.; McAteer, R. T. J.

    2017-08-01

    Daily differential emission measure (DEM) distributions of the solar corona are derived from spectra obtained by the Extreme-ultraviolet Variability Experiment (EVE) over a 4 yr period starting in 2010 near solar minimum and continuing through the maximum of solar cycle 24. The DEMs are calculated using six strong emission features dominated by Fe lines of charge states viii, ix, xi, xii, xiv, and xvi that sample the nonflaring coronal temperature range 0.3-5 MK. A proxy for the non-Fe xviii emission in the wavelength band around the 93.9 Å line is demonstrated. There is little variability in the cool component of the corona (T 2.0 MK) varies by more than an order of magnitude. A discontinuity in the behavior of coronal diagnostics in 2011 February-March, around the time of the first X-class flare of cycle 24, suggests fundamentally different behavior in the corona under solar minimum and maximum conditions. This global state transition occurs over a period of several months. The DEMs are used to estimate the thermal energy of the visible solar corona (of order 1031 erg), its radiative energy loss rate ((2.5-8) × {10}27 erg s-1), and the corresponding energy turnover timescale (about an hour). The uncertainties associated with the DEMs and these derived values are mostly due to the coronal Fe abundance and density and the CHIANTI atomic line database.

  4. Experimental studies of neutron emission spectra in Li(d,xn) reactions for IFMIF

    Energy Technology Data Exchange (ETDEWEB)

    Hagiwara, Masayuki, E-mail: hagi@post.kek.jp [Cyclotron and Radioisotope Center, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Radiation Science Center, High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Itoga, Toshiro, E-mail: itoga@spring8.or.jp [Cyclotron and Radioisotope Center, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Oishi, Takuji, E-mail: oishi.takuji@canon.co.jp [Cyclotron and Radioisotope Center, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Baba, Mamoru [Cyclotron and Radioisotope Center, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan)

    2011-10-01

    To improve the accuracy of the neutron emission data in the {sup nat}Li(d,xn) reaction, which will be used as the neutron source in the International Fusion Materials Irradiation Facility (IFMIF), we measured the double-differential neutron emission cross-sections (DDXs) of the d-Li reaction at 25 MeV at the cyclotron facility of Tohoku University. The DDXs were measured at ten laboratory angles between 0{sup o} and 110{sup o} by the time-of-flight method, using a beam-swinger system and a well-collimated neutron flight channel. We used a two-gain method to obtain over most of the energy range of secondary neutrons and reveal the shape of the overall emission spectra including the breakup peak of incident deuterons near half the incidence energy, and several peaks in the high-energy tail due to stripping reactions. The experimental results compared favorably with those obtained using the extended Serber model.

  5. Optical vibronic emission spectra for irradiation induced F aggregate centers in single crystal α-Al2O3

    Science.gov (United States)

    Mohammad Saliqur, Rahman Abu Zayed; Awata, T.; Yamashita, N.; Xu, Qiu; Atobe, K.

    The optical vibronic emission spectra of the single crystal α-Al2O3 caused by neutron bombardment have been studied. New sharp line features near the 470 nm emission band were found. The phonon side band of the previously found zero-phonon line near the 380 nm emission band is also observed in the present study. Vibronic structures associated with the 470 nm emission band are predominantly featured. The Huang-Rhys factor and the Debye temperature are estimated by a curve fitting method to be 3.2 and 710 K, respectively. It can be seen that the origin of the 470 nm vibronic emission spectra is derived from the Fimg style="vertical-align: text-bottom;" class="inlinematheqn" src="/ampp/image?path=/713648881/915810374/grad_a_398864_o_ilm0001.gif" alt="./GRAD_A_398864_O_XML_IMAGES/GRAD_A_398864_O_ILM0001.gif" border="0" /> type center.

  6. Observations of the Quadrantid meteor shower from 2008 to 2012: Orbits and emission spectra

    Science.gov (United States)

    Madiedo, José M.; Espartero, Francisco; Trigo-Rodríguez, Josep M.; Castro-Tirado, Alberto J.; Pujols, Pep; Pastor, Sensi; de los Reyes, José A.; Rodríguez, Diego

    2016-09-01

    The activity of the Quadrantids in January during several years (2008, 2010, 2011 and 2012) has been investigated in the framework of the SPanish Meteor Network (SPMN). For this purpose, an array of high-sensitivity CCD video devices and CCD all-sky cameras have been used to obtain multi-station observations of these meteors. These allowed to obtain precise radiant and orbital information about this meteoroid stream. This paper presents a large set of orbital data (namely, 85 orbits) of Quadrantid meteoroids. Most meteors produced by these particles were recorded during the activity peak of this shower. Besides, we discuss four Quadrantid emission spectra. The tensile strength of Quadrantid meteoroids has been also obtained.

  7. Observations of the Quadrantid meteor shower from 2008 to 2012: orbits and emission spectra

    CERN Document Server

    Madiedo, José M; Trigo-Rodríguez, Josep M; Castro-Tirado, Alberto J; Pujols, Pep; Pastor, Sensi; Reyes, José A de los; Rodríguez, Diego

    2016-01-01

    The activity of the Quadrantids in January during several years (2008, 2010, 2011 and 2012) has been investigated in the framework of the SPanish Meteor Network (SPMN). For this purpose, an array of high-sensitivity CCD video devices and CCD all-sky cameras have been used to obtain multi-station observations of these meteors. These allowed us to obtain precise radiant and orbital information about this meteoroid stream. This paper presents a large set of orbital data (namely, 85 orbits) of Quadrantid meteoroids. Most meteors produced by these particles were recorded during the activity peak of this shower. Besides, we discuss four Quadrantid emission spectra. The tensile strength of Quadrantid meteoroids has been also obtained.

  8. Scanning tunneling microscope light emission spectra of polycrystalline GeSbTe and SbTe

    Science.gov (United States)

    Uehara, Y.; Kuwahara, M.; Katano, S.; Ushioda, S.

    2009-11-01

    We have observed scanning tunneling microscope light emission (STM-LE) spectra of Ge 2Sb 2Te 5 and Sb 2Te 3. Although these chalcogenide alloys exhibit band gaps less than 0.5 eV, the STM-LE was observed with a narrow spectral width at a photon energy of 1.5 eV for both materials. By analyzing its bias voltage, polarity, and temperature dependencies combined with recently reported theoretical electronic structures, we concluded that the STM-LE is excited by electronic transitions taking place in the local electronic structure having a direct gap-like shape with a band gap of 1.5 eV, commonly found in the electronic structures of both materials.

  9. [Application study of the thermal infrared emissivity spectra in the estimation of salt content of saline soil].

    Science.gov (United States)

    Xia, Jun; Tashpolat, Tiyip; Mamat, Sawut; Zhang, Fei; Han, Gui-Hong

    2012-11-01

    Studying of soil salinization is of great significance for agricultural production in arid area oasis, thermal infrared remote sensing technology provides a new technology and method in this field. Authors used Fourier transform infrared spectrometer to measure the oasis saline soil in field, employed iterative spectrally smooth temperature/emissivity separation algorithm (ISSTES) to separate temperature and emissivity, and acquired the thermal infrared emissivity data of the saline soil. Through researching the emissivity spectral feature of saline soil, and concluded that soil emissivity will reduce with the increasing of salt content from 8 to 13 microm, so emissivity spectra is more sensitive to salt factor from 8 to 9.5 microm. Then, analyzed the correlation between original emissivity spectra and its first derivative, second derivative and normalized ratio with salt content, the result showed that they have a negative correlation relationship between soil emissivity and salt content, and the correlation between emissivity first derivative and salt content is highest, reach to 0.724 2, the corresponding bands are from 8.370 745-8.390 880 microm. Finally, established the quadratic function regression model, its determination coefficient is 0.741 4, and root mean square error is 0.235 5, the result explained that the approach of using thermal infrared emissivity to retrieve the salt content of saline soil is feasible.

  10. X-ray emission of SNRs in nonuniform medium: properties of thermal and nonthermal spectra

    Science.gov (United States)

    Petruk, O.

    2006-05-01

    In this report we consider two effects in the thermal and nonthermal spectra of supernova remnants (SNRs) which could be caused by the nonuniform ISM: i) the mimicry of the thermal X-ray spectrum of SNRs under the nonthermal one and ii) artificial broadening of the high-energy end of the nonthermal X-ray spectrum of SNRs. 1.There is possibility that the nonthermal features in the X-ray spectrum of some supernova remnants may be in fact of the thermal origin. Observed spectrum from SNRs is a superposition of ``individual'' spectra from different small volumes along the line of sight. The plasma is under different conditions in different places in SNR. The thermal X-ray spectrum of emission from a volume with high enough gradients of density and temperature may mimic under nonthermal one. This effect is studied with special attention to the case of supernova remnant evolution in the nonuniform interstellar medium like near molecular cloud. The mimicry-effect may be responsible for the nonthermal properties of X-ray spectra in those SNRs where nonthermal flux in photons with energy nonuniform interstellar medium. Time dependence of the maximum energy of electrons accelerated by the shock is also not able to make the observed spectrum considerably broader. The only possibility to produce broadening in the spectrum is the variation of the maximum energy of electrons over the surface of SNR. In such a case, the obliquity dependence of injection efficiency and/or magnetic field strength make also effect on the shape of the spectrum but their role is of the second order.

  11. The Impact of Non-uniform Thermal Structure on the Interpretation of Exoplanet Emission Spectra

    Science.gov (United States)

    Feng, Y. Katherina; Line, Michael R.; Fortney, Jonathan J.; Stevenson, Kevin B.; Bean, Jacob; Kreidberg, Laura; Parmentier, Vivien

    2016-09-01

    The determination of atmospheric structure and molecular abundances of planetary atmospheres via spectroscopy involves direct comparisons between models and data. While varying in sophistication, most model spectra comparisons fundamentally assume one-dimensional (1D) model physics. However, knowledge from general circulation models and of solar system planets suggests that planetary atmospheres are inherently three-dimensional in their structure and composition. We explore the potential biases resulting from standard “1D” assumptions within a Bayesian atmospheric retrieval framework. Specifically, we show how the assumption of a single 1D thermal profile can bias our interpretation of the thermal emission spectrum of a hot Jupiter atmosphere that is composed of two thermal profiles. We retrieve spectra of unresolved model planets as observed with a combination of the Hubble Space Telescope Wide Field Camera 3 (WFC3)+Spitzer Infrared Array Camera (IRAC) as well as the James Webb Space Telescope (JWST) under varying differences in the two thermal profiles. For WFC3+IRAC, there is a significantly biased estimate of CH4 abundance using a 1D model when the contrast is 80%. For JWST, two thermal profiles are required to adequately interpret the data and estimate the abundances when contrast is greater than 40%. We also apply this preliminary concept to the recent WFC3+IRAC phase curve data of the hot Jupiter WASP-43b. We see similar behavior as present in our simulated data: while the {{{H}}}2{{O}} abundance determination is robust, CH4 is artificially well-constrained to incorrect values under the 1D assumption. Our work demonstrates the need to evaluate model assumptions in order to extract meaningful constraints from atmospheric spectra and motivates exploration of optimal observational setups.

  12. Molecular phonons and their absorption/emission spectra from the far IR to microwaves

    CERN Document Server

    Papoular, Renaud

    2015-01-01

    Together with their fingerprint modes, molecules carry coherent vibrations of all their atoms (phonons). Phonon spectra extend from $\\sim$20 to more than $10^{4}\\,\\mu$m, depending on molecular size. These spectra are discrete but large assemblies of molecules of the same family, differing only by minor structural details, will produce continua. As such assemblies are expected to exist in regions where dust accumulates, they are bound to contribute to the observed continua underlying the Unidentified Infrared Bands and the 21-mum band of planetary nebulae as well as to the diffuse galactic emission surveyed by the Planck astronomical satellite and other means. The purpose of this work is to determine, for carbon-rich molecules, the intensity of such continua and their extent into the millimetric range, and to evaluate their detectability in this range. The rules governing the spectral distributions of phonons are derived and shown to differ from those which obtain in the solid state. Their application allow th...

  13. The impact of non-uniform thermal structure on the interpretation of exoplanet emission spectra

    Science.gov (United States)

    Feng, Ying; Fortney, Jonathan J.; Line, Michael R.

    2016-10-01

    Observations and models have revealed the complex and dynamic states of exoplanetary atmospheres. In particular, the atmospheres of warm and hot gas giants have opened the doors to physical and chemical regimes unseen in our solar system. To understand their thermal structures and chemical abundances, the field has been moving towards inverse models, or ``retrievals.'' Traditionally, one retrieves what are supposed to be 1D hemispheric average atmospheric conditions. However, the real spectra are produced by 3D structures that feature hot and cool spots, chemical gradients, clouds, etc. How well does a 1D retrieval represent, or misrepresent, a complex reality?Here, we investigate the biases accompanying the 1D interpretation of retrievals by putting more complex retrieval scenarios to the test on emission spectra. Our first scenario is the emission from a hypothetical HD 189733b-like planet at first or third quarter phase, featuring a ``hot'' dayside and ``colder'' nightside thermal profile. We simulate JWST and WFC3+IRAC data and compare the results of retrieving for 1 profile (1 T-Ps) and abundances versus for 2 profiles (2 T-Ps) and abundances. We also examine the effects of increasing contrast between the two profiles. We find that, for both JWST and WFC3+IRAC, when the contrast is large (80% difference between the temperatures at the top of the atmosphere), the 1 T-P approach shows well constrained abundances -- but the retrieved values are inaccurate. When we apply the 2 T-P approach, we better recover the true value. We also demonstrate the effect on real WASP-43b HST+Spitzer phase curve data: invoking a second profile indeed reveals that 1 T-P returns a well-constrained, but likely false, abundance of methane. We also quantify which wavelengths are more sensitive to temperature profile differences. Our work is greatly complementary to observational studies.In the future, we will expand to retrieve from spectra at different phases and the study of dayside

  14. High-resolution far ultraviolet emission spectra of electron-excited molecular deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Abgrall, H.; Roueff, E. [Observatoire de Paris, Section de Meudon, DAEC and CNRS UMR 8631, 92195 Meudon Cedex (France); Xianming Liu; Shemansky, D.E. [Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA 90089 (United States); James, G.K. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    1999-08-14

    The high-resolution (full width at half maximum {delta} {lambda} = 0.11 A) emission spectrum of the deuterium molecule produced by electron-impact excitation at 100 eV has been measured in the wavelength range 1200-1660 A. In conjunction with the experimental measurement, transition probabilities of B{sup 1}{sigma}{sub u}{sup +}-X{sup 1}{sigma}{sub g}{sup +}, C{sup 1}{pi}{sub u}-X{sup 1}{sigma}{sub g}{sup +}, B'{sup 1}{sigma}{sub u}{sup +}-X{sup 1}{sigma}{sub g}{sup +} and D{sup 1}{pi}{sub u}-X{sup 1}{sigma}{sub g}{sup -} band systems are calculated. Synthetic spectra based on the calculated transition probabilities are in very good agreement with the optically thin experimental spectra. While centrifugal effects on the overall Lyman band emission intensity in D{sub 2} and H{sub 2} are similar, the effect of rotation-vibrational perturbations between the B{sup 1}{sigma}{sub u}{sup +} and C{sup 1}{pi}{sub u}{sup +} states on spectral intensities is found to be less significant in D{sub 2}. Excitations via isotropic ({delta} J = 0) and anisotropic ({delta}J = {+-} 2, and 0) interactions for the dipole forbidden E, F{sup 1}{sigma}{sub g}{sup +}-X{sup 1}{sigma}{sub g}{sup +} transition are inferred from the measured spectra. Excitation cross sections of the B{sup 1}{sigma}{sub u}{sup +}-X{sup 1}{sigma}{sub g}{sup +} and C{sup 1}{pi}{sub u}-X{sup 1}{sigma}{sub g}{sup +} bands, along with the estimated E, F{sup 1}{sigma}{sub g}{sup +}-B{sup 1}{sigma}{sub u}{sup +} cascade cross section, for D{sub 2} are obtained. (author)

  15. Time resolved spectra in the infrared absorption and emission from shock heated hydrocarbons. [in interstellar medium

    Science.gov (United States)

    Bauer, S. H.; Borchardt, D. B.

    1990-01-01

    The wavelength range of a previously constructed multichannel fast recording spectrometer was extended to the mid-infrared. With the initial configuration, light intensities were recorded simultaneously with a silicon-diode array simultaneously at 20 adjacent wavelengths, each with a 20-micron time resolution. For studies in the infrared, the silicon diodes were replaced by a 20-element PbSe array of similar dimensions, cooled by a three-stage thermoelectric device. It is proposed that infrared emissions could be due to shock-heated low molecular-weight hydrocarbons. The full Swan band system appeared in time-integrated emission spectra from shock-heated C2H2; no soot was generated. At low resolution, the profiles on the high-frequency side of the black body maximum show no distinctive features. These could be fitted to Planck curves, with temperatures that declined with time from an initial high that was intermediate between T5 (no conversion) and T5(eq).

  16. ELECTROMAGNETIC EMISSION FROM LONG-LIVED BINARY NEUTRON STAR MERGER REMNANTS. II. LIGHT CURVES AND SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, Daniel M. [Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Am Mühlenberg 1, D-14476 Potsdam-Golm (Germany); Ciolfi, Riccardo, E-mail: daniel.siegel@aei.mpg.de, E-mail: riccardo.ciolfi@unitn.it [Physics Department, University of Trento, Via Sommarive 14, I-38123 Trento (Italy)

    2016-03-01

    Recent observations indicate that in a large fraction of binary neutron star (BNS) mergers a long-lived neutron star (NS) may be formed rather than a black hole. Unambiguous electromagnetic (EM) signatures of such a scenario would strongly impact our knowledge on how short gamma-ray bursts (SGRBs) and their afterglow radiation are generated. Furthermore, such EM signals would have profound implications for multimessenger astronomy with joint EM and gravitational-wave (GW) observations of BNS mergers, which will soon become reality thanks to the ground-based advanced LIGO/Virgo GW detector network. Here we explore such EM signatures based on the model presented in a companion paper, which provides a self-consistent evolution of the post-merger system and its EM emission up to ∼10{sup 7} s. Light curves and spectra are computed for a wide range of post-merger physical properties. We present X-ray afterglow light curves corresponding to the “standard” and the “time-reversal” scenario for SGRBs (prompt emission associated with the merger or with the collapse of the long-lived NS). The light curve morphologies include single and two-plateau features with timescales and luminosities that are in good agreement with Swift observations. Furthermore, we compute the X-ray signal that should precede the SGRB in the time-reversal scenario, the detection of which would represent smoking-gun evidence for this scenario. Finally, we find a bright, highly isotropic EM transient peaking in the X-ray band at ∼10{sup 2}–10{sup 4} s after the BNS merger with luminosities of L{sub X} ∼ 10{sup 46}–10{sup 48} erg s{sup −1}. This signal represents a very promising EM counterpart to the GW emission from BNS mergers.

  17. Fluorescence Excitation-Emission Matrix Regional Integration to Quantify Spectra for Dissolved Organic Matter

    Science.gov (United States)

    Chen, W.; Westerhoff, P.; Leenheer, J.A.; Booksh, K.

    2003-01-01

    Excitation-emission matrix (EEM) fluorescence spectroscopy has been widely used to characterize dissolved organic matter (DOM) in water and soil. However, interpreting the >10,000 wavelength-dependent fluorescence intensity data points represented in EEMs has posed a significant challenge. Fluorescence regional integration, a quantitative technique that integrates the volume beneath an EEM, was developed to analyze EEMs. EEMs were delineated into five excitation-emission regions based on fluorescence of model compounds, DOM fractions, and marine waters or freshwaters. Volumetric integration under the EEM within each region, normalized to the projected excitation-emission area within that region and dissolved organic carbon concentration, resulted in a normalized region-specific EEM volume (??i,n). Solid-state carbon nuclear magnetic resonance (13C NMR), Fourier transform infrared (FTIR) analysis, ultraviolet-visible absorption spectra, and EEMs were obtained for standard Suwannee River fulvic acid and 15 hydrophobic or hydrophilic acid, neutral, and base DOM fractions plus nonfractionated DOM from wastewater effluents and rivers in the southwestern United States. DOM fractions fluoresced in one or more EEM regions. The highest cumulative EEM volume (??T,n = ????i,n) was observed for hydrophobic neutral DOM fractions, followed by lower ??T,n values for hydrophobic acid, base, and hydrophilic acid DOM fractions, respectively. An extracted wastewater biomass DOM sample contained aromatic protein- and humic-like material and was characteristic of bacterial-soluble microbial products. Aromatic carbon and the presence of specific aromatic compounds (as indicated by solid-state 13C NMR and FTIR data) resulted in EEMs that aided in differentiating wastewater effluent DOM from drinking water DOM.

  18. Electromagnetic Emission from Long-lived Binary Neutron Star Merger Remnants. II. Lightcurves and Spectra

    Science.gov (United States)

    Siegel, Daniel M.; Ciolfi, Riccardo

    2016-03-01

    Recent observations indicate that in a large fraction of binary neutron star (BNS) mergers a long-lived neutron star (NS) may be formed rather than a black hole. Unambiguous electromagnetic (EM) signatures of such a scenario would strongly impact our knowledge on how short gamma-ray bursts (SGRBs) and their afterglow radiation are generated. Furthermore, such EM signals would have profound implications for multimessenger astronomy with joint EM and gravitational-wave (GW) observations of BNS mergers, which will soon become reality thanks to the ground-based advanced LIGO/Virgo GW detector network. Here we explore such EM signatures based on the model presented in a companion paper, which provides a self-consistent evolution of the post-merger system and its EM emission up to ˜107 s. Light curves and spectra are computed for a wide range of post-merger physical properties. We present X-ray afterglow light curves corresponding to the “standard” and the “time-reversal” scenario for SGRBs (prompt emission associated with the merger or with the collapse of the long-lived NS). The light curve morphologies include single and two-plateau features with timescales and luminosities that are in good agreement with Swift observations. Furthermore, we compute the X-ray signal that should precede the SGRB in the time-reversal scenario, the detection of which would represent smoking-gun evidence for this scenario. Finally, we find a bright, highly isotropic EM transient peaking in the X-ray band at ˜102-104 s after the BNS merger with luminosities of LX ˜ 1046-1048 erg s-1. This signal represents a very promising EM counterpart to the GW emission from BNS mergers.

  19. Infrared Space Observatory Spectra of R Coronae Borealis Stars; 1, Emission Features in the Interval 3 - 25 microns

    CERN Document Server

    Lambert, D L; Pandey, G; Ivans, I I; Lambert, David L.; Pandey, Gajendra; Ivans, Inese I.

    2001-01-01

    Infrared Space Observatory 3 - 25 $\\mu$m spectra of the R Coronae Borealis stars V854 Cen, R CrB, and RY Sgr are presented and discussed. Sharp emission features coincident in wavelengths with the well known Unidentified Emission Features are present in the spectrum of V854 Cen but not of R CrB or RY Sgr. Since V854 Cen is not particularly H-poor and has a 1000 times more H than the other stars, the emission features are probably from a carrier containing hydrogen. There is a correspondence between the features and emission from laboratory samples of hydrogenated amorphous carbon. A search for C$_{60}$ in emission or absorption proved negative. Amorphous carbon particles account for the broad emission features seen between 6 - 14 $\\mu$m in the spectrum of each star.

  20. Bayesian electron density inference from JET lithium beam emission spectra using Gaussian processes

    Science.gov (United States)

    Kwak, Sehyun; Svensson, J.; Brix, M.; Ghim, Y.-C.; Contributors, JET

    2017-03-01

    A Bayesian model to infer edge electron density profiles is developed for the JET lithium beam emission spectroscopy (Li-BES) system, measuring Li I (2p-2s) line radiation using 26 channels with  ∼1 cm spatial resolution and 10∼ 20 ms temporal resolution. The density profile is modelled using a Gaussian process prior, and the uncertainty of the density profile is calculated by a Markov Chain Monte Carlo (MCMC) scheme. From the spectra measured by the transmission grating spectrometer, the Li I line intensities are extracted, and modelled as a function of the plasma density by a multi-state model which describes the relevant processes between neutral lithium beam atoms and plasma particles. The spectral model fully takes into account interference filter and instrument effects, that are separately estimated, again using Gaussian processes. The line intensities are inferred based on a spectral model consistent with the measured spectra within their uncertainties, which includes photon statistics and electronic noise. Our newly developed method to infer JET edge electron density profiles has the following advantages in comparison to the conventional method: (i) providing full posterior distributions of edge density profiles, including their associated uncertainties, (ii) the available radial range for density profiles is increased to the full observation range (∼26 cm), (iii) an assumption of monotonic electron density profile is not necessary, (iv) the absolute calibration factor of the diagnostic system is automatically estimated overcoming the limitation of the conventional technique and allowing us to infer the electron density profiles for all pulses without preprocessing the data or an additional boundary condition, and (v) since the full spectrum is modelled, the procedure of modulating the beam to measure the background signal is only necessary for the case of overlapping of the Li I line with impurity lines.

  1. Retrieval of stratospheric ozone profiles from MIPAS/ENVISAT limb emission spectra: a sensitivity study

    Directory of Open Access Journals (Sweden)

    N. Glatthor

    2005-11-01

    Full Text Available We report on the dependance of ozone volume mixing ratio profiles, retrieved from spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS, on different retrieval setups such as different a-priori profiles, regularization strengths and spectral regions used for analysis. MIPAS is a spaceborne limb-viewing Fourier transform infrared (FTIR emission spectrometer, by which vertical profiles of various trace gases can be measured simultaneously. Purpose of this investigation is to check and to optimize the current retrieval setup. The choice of different a-priori profiles, of a different approach to retrieve the continuum radiation, and of a weaker regularization than in the reference data version (V2_O3_2 causes only small to moderate deviations of up to ±0.2, −0.3 and ±0.5 ppmv, respectively, in the retrieved ozone volume mixing ratios below 60 km altitude. Use of different microwindow sets optimized for polar, mid-latitude and tropical conditions results in deviations of up to ±1.5 ppmv in the altitude region of the ozone maximum, exceeding the total estimated retrieval error of 0.65 ppmv (polar regions – 1.2 ppmv (tropics in this height region. Therefore, to avoid latitudinal artefacts, one fixed set of microwindows is considered more appropriate for retrieval of a whole orbit rather than a latitude-dependent microwindow selection. For this task the microwindow set optimized for the polar atmosphere was found to be better suitable than its midlatitude and tropical counterparts. The results from the different microwindow sets, which variably cover MIPAS spectral bands A (685–970 cm−1 and AB (1020–1170 cm−1, indicated a positive bias of up to 1ppmv between the ozone maxima retrieved from the ozone emission in MIPAS band AB only and from combined analysis of MIPAS bands A and AB. Further investigations showed that this discrepancy can be caused by a bias between the radiance calibration of

  2. Detection of Low-energy Breaks in Gamma-Ray Burst Prompt Emission Spectra

    Science.gov (United States)

    Oganesyan, Gor; Nava, Lara; Ghirlanda, Giancarlo; Celotti, Annalisa

    2017-09-01

    The radiative process responsible for gamma-ray burst (GRB) prompt emission has not been identified yet. If dominated by fast-cooling synchrotron radiation, the part of the spectrum immediately below the ν {F}ν peak energy should display a power-law behavior with slope {α }2=-3/2, which breaks to a higher value {α }1=-2/3 (i.e., to a harder spectral shape) at lower energies. Prompt emission spectral data (usually available down to ∼ 10{--}20 keV) are consistent with one single power-law behavior below the peak, with typical slope =-1, higher than (and then inconsistent with) the expected value {α }2=-3/2. To better characterize the spectral shape at low energy, we analyzed 14 GRBs for which the Swift X-ray Telescope started observations during the prompt. When available, Fermi-GBM observations have been included in the analysis. For 67% of the spectra, models that usually give a satisfactory description of the prompt (e.g., the Band model) fail to reproduce the 0.5–1000 keV spectra: low-energy data outline the presence of a spectral break around a few keV. We then introduce an empirical fitting function that includes a low-energy power law {α }1, a break energy {E}{break}, a second power law {α }2, and a peak energy {E}{peak}. We find =-0.66 (σ =0.35), =0.63 (σ =0.20), =-1.46 (σ =0.31), and =2.1 (σ =0.56). The values and are very close to expectations from synchrotron radiation. In this context, {E}{break} corresponds to the cooling break frequency. The relatively small ratio {E}{peak}/{E}{break}∼ 30 suggests a regime of moderately fast cooling, which might solve the long-lasting problem of the apparent inconsistency between measured and predicted low-energy spectral index.

  3. Chlorophyll Fluorescence Emissions of Vegetation Canopies From High Resolution Field Reflectance Spectra

    Science.gov (United States)

    Middleton, E. M.; Corp, L. A.; Daughtry, C. S. T.; Campbell, P. K. Entcheva

    2006-01-01

    A two-year experiment was performed on corn (Zea mays L.) crops under nitrogen (N) fertilization regimes to examine the use of hyperspectral canopy reflectance information for estimating chlorophyll fluorescence (ChlF) and vegetation production. Fluorescence of foliage in the laboratory has proven more rigorous than reflectance for correlation to plant physiology. Especially useful are emissions produced from two stable red and far-red chlorophyll ChlF peaks centered at 685V10 nm and 735V5 nm. Methods have been developed elsewhere to extract steady state solar induced fluorescence (SF) from apparent reflectance of vegetation canopies/landscapes using the Fraunhofer Line Depth (FLD) principal. Our study utilized these methods in conjunction with field-acquired high spectral resolution canopy reflectance spectra obtained in 2004 and 2005 over corn crops, as part of an ongoing multi-year experiment at the USDA/Agriculture Research Service in Beltsville, MD. A spectroradiometer (ASD-FR Fieldspec Pro, Analytical Spectral Devices, Inc., Boulder, CO) was used to measure canopy radiances 1 m above plant canopies with a 22deg field of view and a 0deg nadir view zenith angle. Canopy and plant measurements were made at the R3 grain fill reproductive stage on 3-4 replicate N application plots provided seasonal inputs of 280, 140, 70, and 28 kg N/ha. Leaf level measurements were also made which included ChlF, photosynthesis, and leaf constituents (photosynthetic pigment, carbon (C), and N contents). Crop yields were determined at harvest. SIF intensities for ChlF were derived directly from canopy reflectance spectra in specific narrowband regions associated with atmospheric oxygen absorption features centered at 688 and 760 nm. The red/far-red S F ratio derived from these field reflectance spectra successfully discriminated foliar pigment levels (e.g., total chlorophyll, Chl) associated with N application rates in both corn crops. This canopy-level spectral ratio was also

  4. Identifying student and teacher difficulties in interpreting atomic spectra using a quantum model of emission and absorption of radiation

    Science.gov (United States)

    Savall-Alemany, Francisco; Domènech-Blanco, Josep Lluís; Guisasola, Jenaro; Martínez-Torregrosa, Joaquín

    2016-06-01

    Our study sets out to identify the difficulties that high school students, teachers, and university students encounter when trying to explain atomic spectra. To do so, we identify the key concepts that any quantum model for the emission and absorption of electromagnetic radiation must include to account for the gas spectra and we then design two questionnaires, one for teachers and the other for students. By analyzing the responses, we conclude that (i) teachers lack a quantum model for the emission and absorption of electromagnetic radiation capable of explaining the spectra, (ii) teachers and students share the same difficulties, and (iii) these difficulties concern the model of the atom, the model of radiation, and the model of the interaction between them.

  5. Electronic spectra of 2- and 3-tolunitrile in the gas phase. II. Geometry changes from Franck-Condon fits of fluorescence emission spectra

    Science.gov (United States)

    Gmerek, Felix; Stuhlmann, Benjamin; Álvarez-Valtierra, Leonardo; Pratt, David W.; Schmitt, Michael

    2016-02-01

    We determined the changes of the geometries of 2- and 3-tolunitrile upon excitation to the lowest excited singlet states from Franck-Condon fits of the vibronic intensities in several fluorescence emission spectra and of the rotational constant changes upon excitation. These structural changes can be connected to the altered electron distribution in the molecules and are compared to the results of ab initio calculations. We show how the torsional barriers of the methyl groups in both components are used as probe of the molecular changes upon electronic excitation.

  6. The non-thermal emission of extended radio galaxy lobes with curved electron spectra

    CERN Document Server

    Duffy, Peter

    2011-01-01

    The existing theoretical framework for the energies stored in the synchrotron-emitting lobes of radio galaxies and quasars doesn't properly account for the curved spectral shape that many of them exhibit. We characterise these spectra using parameters that are straightforwardly observable in the era of high-resolution, low-frequency radio astronomy: the spectral curvature and the turnover in the frequency spectrum. This characterisation gives the Lorentz factor at the turnover in the energy distribution (we point out that this is distinctly different from the Lorentz factor corresponding to the turnover frequency in a way that depends on the amount of curvature in the spectrum) and readily gives the equipartition magnetic field strength and the total energy of the radiating plasma obviating the need for any assumed values of the cutoff frequencies to calculate these important physical quantities. This framework readily yields the form of the X-ray emission due to inverse-Compton (IC) scattering of Cosmic Micr...

  7. Electromagnetic emission from long-lived binary neutron star merger remnants II: lightcurves and spectra

    CERN Document Server

    Siegel, Daniel M

    2015-01-01

    Recent observations indicate that in a large fraction of binary neutron star (BNS) mergers a long-lived neutron star (NS) may be formed rather than a black hole. Unambiguous electromagnetic (EM) signatures of such a scenario would strongly impact our knowledge on how short gamma-ray bursts (SGRBs) and their afterglow radiation are generated. Furthermore, such EM signals would have profound implications for multimessenger astronomy with joint EM and gravitational-wave (GW) observations of BNS mergers, which will soon become reality with the ground-based advanced LIGO/Virgo GW detector network starting its first science run this year. Here we explore such EM signatures based on the model presented in a companion paper, which provides a self-consistent evolution of the post-merger system and its EM emission starting from an early baryonic wind phase and resulting in a final pulsar wind nebula that is confined by the previously ejected material. Lightcurves and spectra are computed for a wide range of post-merger...

  8. VUV emission spectra from binary rare gas mixtures near the resonance lines of Xe I and Kr I

    CERN Document Server

    Morozov, A; Gerasimov, G; Arnesen, A; Hallin, R

    2003-01-01

    Emission spectra of Xe-X (X = He, Ne, Ar and Kr) and of Kr-Y (Y = He, Ne and Ar) mixtures with low concentrations of the heavier gases (0.1-1%) and moderate total pressures (50-200 hPa) have been recorded near each of the two resonance lines of Xe and Kr in DC glow capillary discharges. The recorded intense emissions have narrow spectral profiles with FWHM of about 0.1 nm. The profiles are very similar in shape to profiles of known high resolution absorption spectra recorded at comparable gas pressures. A tentative identification of the emission structures is given, which involves transitions in heteronuclear molecules and quasimolecules between weakly-bound states.

  9. Computing the Absorption and Emission Spectra of 5-Methylcytidine in Different Solvents: A Test-Case for Different Solvation Models.

    Science.gov (United States)

    Martínez-Fernández, L; Pepino, A J; Segarra-Martí, J; Banyasz, A; Garavelli, M; Improta, R

    2016-09-13

    The optical spectra of 5-methylcytidine in three different solvents (tetrahydrofuran, acetonitrile, and water) is measured, showing that both the absorption and the emission maximum in water are significantly blue-shifted (0.08 eV). The absorption spectra are simulated based on CAM-B3LYP/TD-DFT calculations but including solvent effects with three different approaches: (i) a hybrid implicit/explicit full quantum mechanical approach, (ii) a mixed QM/MM static approach, and (iii) a QM/MM method exploiting the structures issuing from molecular dynamics classical simulations. Ab-initio Molecular dynamics simulations based on CAM-B3LYP functionals have also been performed. The adopted approaches all reproduce the main features of the experimental spectra, giving insights on the chemical-physical effects responsible for the solvent shifts in the spectra of 5-methylcytidine and providing the basis for discussing advantages and limitations of the adopted solvation models.

  10. Analysis of arc emission spectra of stainless steel electric arc furnace slag affected by fluctuating arc voltage.

    Science.gov (United States)

    Aula, Matti; Mäkinen, Ari; Fabritius, Timo

    2014-01-01

    Control of chromium oxidation in the electric arc furnace (EAF) is a significant problem in stainless steel production due to variations of the chemical compositions in the EAF charge. One potential method to control chromium oxidation is to analyze the emission spectrum of the electric arc in order to find indicators of rising chromium content in slag. The purpose of this study was to determine if slag composition can be gained by utilizing electric arc emission spectra in the laboratory environment, despite electric arc voltage fluctuations and varying slag composition. The purpose of inducing voltage fluctuation was to simulate changes in the industrial EAF process. The slag samples were obtained from Outokumpu Stainless Oy Tornio Works, and three different arc currents were used. The correlation analysis showed that the emission spectra offer numerous peak ratios with high correlations to the X-ray fluorescence-measured slag CrO(x)/FeO(x) and MnO/SiO2 ratios. These ratios are useful in determining if the reduction agents have been depleted in the EAF. The results suggest that analysis of laboratory-scale electric arc emission spectra is suitable for indicating the high CrO(x) or MnO content of the slag despite the arc fluctuations. Reliable analysis of other slag components was not successful.

  11. Practical retrieval of land surface emissivity spectra in 8-14 μm from hyperspectral thermal infrared data.

    Science.gov (United States)

    Wu, Hua; Wang, Ning; Ni, Li; Tang, Bo-Hui; Li, Zhao-Liang

    2012-10-22

    A practical physics-based regression method was developed and evaluated for nearly real time estimate of land surface emissivity spectra in 8-14 μm from hyperspectral thermal infrared data. Two spectral emissivity libraries and one atmospheric profile database fully covering all the possible situations for clear sky conditions were elaborately selected to simulate the radiances at the top of the atmosphere (TOA). The regression coefficients were determined by the main principal components of emissivity spectra and those of simulated brightness temperature at TOA using a ridge regression method. The experience with the simulated Interferometer Atmospheric Sounding Instrument (IASI) data showed that the emissivity spectra could be retrieved under clear sky conditions with root mean square errors of 0.015 and 0.03 for 714-970 cm(-1) (10.3-14.0 μm) and 970-1250 cm(-1) (8.0-10.3 μm), respectively, for various land surface and atmospheric conditions. This indicates the proposed method may be robust and applicable for all hyperspectral infrared sensors.

  12. Excitation Emission Matrix Spectra (EEMS) of Chromophoric Dissolved Organic Matter Produced during Microbial Incubation

    Science.gov (United States)

    McDonald, N.; Nelson, N. B.; Parsons, R.

    2013-12-01

    The chromophoric or light-absorbing fraction of dissolved organic matter (CDOM) is present ubiquitously in natural waters and has a significant impact on ocean biogeochemistry, affecting photosynthesis and primary production as well direct and indirect photochemical reactions (Siegel et al., 2002; Nelson et al., 2007). It has been largely researched in the past few decades, however the exact chemical composition remains unknown. Instrumental methods of analysis including simultaneous excitation-emission fluorescence spectra have allowed for further insight into source and chemical composition. While certain excitation-emission peaks have been associated with ';marine' sources, they have not been exclusively linked to bacterial production of CDOM (Coble, 1996; Zepp et al., 2004). In this study, ';grazer diluted' seawater samples (70% 0.2μm filtered water; 30% whole water) were collected at the Bermuda Atlantic Time Series (BATS) site in the Sargasso Sea (31° 41' N; 64° 10' W) and incubated with an amendment of labile dissolved organic carbon (10μM C6H12O6), ammonium (1μM NH4Cl) and phosphate (0.1μM K2HPO4) to facilitate bacterial production. These substrates and concentrations have been previously shown to facilitate optimum bacterial and CDOM production (Nelson et al., 2004). Sample depths were chosen at 1m and 200m as water at these depths has been exposed to UV light (the Subtropical Mode Water at 200m has been subducted from the surface) and therefore has low initial concentrations of CDOM. After the samples were amended, they were incubated at in-situ temperatures in the dark for 72 hours, with bacteria counts, UV-Vis absorption and EEMS measurements taken at 6-8 hour intervals. Dissolved organic carbon (DOC) measurements were collected daily. For the surface water experiment specific bacteria populations were investigated using Fluorescence In-Situ Hybridization (FISH) analysis. Results showed a clear production of bacteria and production of CDOM, which

  13. State-by-state emission spectra fitting for non-equilibrium plasmas: OH spectra of surface barrier discharge at argon/water interface

    Science.gov (United States)

    Voráč, Jan; Synek, Petr; Procházka, Vojtěch; Hoder, Tomáš

    2017-07-01

    Optical emission spectroscopy applied to non-equilibrium plasmas in molecular gases can give important information on basic plasma parameters, including the rotational and vibrational temperatures and densities of the investigated radiative states. In order to precisely understand the non-equilibrium of rotational-vibrational state distribution from the investigated spectra without limiting presumptions, a state-by-state temperature-independent fitting procedure is the ideal approach. In this paper, we present a novel software tool developed for this purpose, freely available for the scientific community. The introduced tool offers a convenient way to construct Boltzmann plots even from partially overlapping spectra, in a user-friendly environment. We apply the novel software to the challenging case of OH spectra in surface streamer discharges generated from the triple-line of the argon/water/dielectrics interface. After the barrier discharge is characterised by ICCD and electrical measurements, the spatially and phase resolved rotational temperatures from N2(C-B) and OH(A-X) spectra are determined and compared. The precise analysis shows that OH(A) states with quantum numbers ≤ft({{v}\\prime}=0,~9≤slant {{N}\\prime}≤slant 13\\right) are overpopulated with respect to the found two-Boltzmann distribution. We hypothesise that fast vibrational-energy transfer is responsible for this phenomenon, observed here for the first time. Finally, the vibrational temperature of the plasma and the relative populations of hot and cold OH(A) states are quantified spatially and phase resolved.

  14. c2d Spitzer IRS spectra of embedded low-mass young stars: gas-phase emission lines

    Science.gov (United States)

    Lahuis, F.; van Dishoeck, E. F.; Jørgensen, J. K.; Blake, G. A.; Evans, N. J.

    2010-09-01

    Context. A survey of mid-infrared gas-phase emission lines of H2, H2O and various atoms toward a sample of 43 embedded low-mass young stars in nearby star-forming regions is presented. The sources are selected from the Spitzer “Cores to Disks” (c2d) legacy program. Aims: The environment of embedded protostars is complex both in its physical structure (envelopes, outflows, jets, protostellar disks) and the physical processes (accretion, irradiation by UV and/or X-rays, excitation through slow and fast shocks) which take place. The mid-IR spectral range hosts a suite of diagnostic lines which can distinguish them. A key point is to spatially resolve the emission in the Spitzer-IRS spectra to separate extended PDR and shock emission from compact source emission associated with the circumstellar disk and jets. Methods: An optimal extraction method is used to separate both spatially unresolved (compact, up to a few hundred AU) and spatially resolved (extended, thousand AU or more) emission from the IRS spectra. The results are compared with the c2d disk sample and literature PDR and shock models to address the physical nature of the sources. Results: Both compact and extended emission features are observed. Warm (T_ex few hundred K) H2, observed through the pure rotational H2 S(0), S(1) and S(2) lines, and [S i] 25 μm emission is observed primarily in the extended component. [S i] is observed uniquely toward truly embedded sources and not toward disks. On the other hand hot (T_ex ⪆ 700 K) H2, observed primarily through the S(4) line, and [Ne ii] emission is seen mostly in the spatially unresolved component. [Fe ii] and [Si ii] lines are observed in both spatial components. Hot H2O emission is found in the spatially unresolved component of some sources. Conclusions: The observed emission on ≥1000 AU scales is characteristic of PDR emission and likely originates in the outflow cavities in the remnant envelope created by the stellar wind and jets from the embedded

  15. Mid-Infrared Atomic Fine-Structure Emission Line Spectra of Luminous Infrared Galaxies: Spitzer/IRS Spectra of the GOALS Sample

    CERN Document Server

    Inami, H; Charmandaris, V; Groves, B; Kewley, L; Petric, A; Stierwalt, S; Díaz-Santos, T; Surace, J; Rich, J; Haan, S; Howell, J; Evans, A; Mazzarella, J; Marshall, J; Appleton, P; Lord, S; Spoon, H; Frayer, D; Matsuhara, H; Veilleux, S

    2013-01-01

    We present the data and our analysis of MIR fine-structure emission lines detected in Spitzer/IRS high-res spectra of 202 local LIRGs observed as part of the GOALS project. We detect emission lines of [SIV], [NeII], [NeV], [NeIII], [SIII]18.7, [OIV], [FeII], [SIII]33.5, and [SiII]. Over 75% of our galaxies are classified as starburst (SB) sources in the MIR. We compare ratios of the emission line fluxes to stellar photo- and shock-ionization models to constrain the gas properties in the SB nuclei. Comparing the [SIV]/[NeII] and [NeIII]/[NeII] ratios to the Starburst99-Mappings III models with an instantaneous burst history, the line ratios suggest that the SB in our LIRGs have ages of 1-4.5Myr, metallicities of 1-2Z_sun, and ionization parameters of 2-8e7cm/s. Based on the [SIII]/[SIII] ratios, the electron density in LIRG nuclei has a median electron density of ~300cm-3 for sources above the low density limit. We also find that strong shocks are likely present in 10 SB sources. A significant fraction of the ...

  16. Compact characterization of liquid absorption and emission spectra using linear variable filters integrated with a CMOS imaging camera

    Science.gov (United States)

    Wan, Yuhang; Carlson, John A.; Kesler, Benjamin A.; Peng, Wang; Su, Patrick; Al-Mulla, Saoud A.; Lim, Sung Jun; Smith, Andrew M.; Dallesasse, John M.; Cunningham, Brian T.

    2016-07-01

    A compact analysis platform for detecting liquid absorption and emission spectra using a set of optical linear variable filters atop a CMOS image sensor is presented. The working spectral range of the analysis platform can be extended without a reduction in spectral resolution by utilizing multiple linear variable filters with different wavelength ranges on the same CMOS sensor. With optical setup reconfiguration, its capability to measure both absorption and fluorescence emission is demonstrated. Quantitative detection of fluorescence emission down to 0.28 nM for quantum dot dispersions and 32 ng/mL for near-infrared dyes has been demonstrated on a single platform over a wide spectral range, as well as an absorption-based water quality test, showing the versatility of the system across liquid solutions for different emission and absorption bands. Comparison with a commercially available portable spectrometer and an optical spectrum analyzer shows our system has an improved signal-to-noise ratio and acceptable spectral resolution for discrimination of emission spectra, and characterization of colored liquid’s absorption characteristics generated by common biomolecular assays. This simple, compact, and versatile analysis platform demonstrates a path towards an integrated optical device that can be utilized for a wide variety of applications in point-of-use testing and point-of-care diagnostics.

  17. The relative number of Seyfert 2 galaxies. I - Spectra of emission-line galaxies in the Wasilewski field

    Science.gov (United States)

    Osterbrock, Donald E.; Shaw, Richard A.

    1988-04-01

    Slit spectra were obtained of all the Seyfert galaxy candidates and many other emission-line galaxies discovered (or recovered) by Wasilewski in his objective-prism survey centered on the region of North Galactic Pole. Redshifts and relative emission-line fluxes were measured for these galaxies, and all of their spectra were classified. Per unit volume of space, the relative numbers of Seyfert (1+1.5) to Seyfert (1.8+1.9) to Seyfert 2 are approximately 0.1/0.1/0.8. If the same galaxies were to evolve through all these stages, they would spend most of their AGN lifetimes as Seyfert 2s. If all Seyfert nuclei were similar objects with central broad-line regions hidden by obscuring disks to various extents, the disks would be thick and the line broadening due to any presumed rotational or radial velocity field in the plane of the disk would be greatly reduced by projection effects.

  18. Advances in physical study of high enthalpy plasma jets of technological interest: emission spectra and plasma characteristics

    Science.gov (United States)

    Belevtsev, A. A.; Chinnov, V. F.; Isakaev, E. Kh.; Markin, A. V.; Tazikova, T. F.; Tereshkin, S. A.

    1998-10-01

    Offers a comprehensive study of the emission spectra and plasma characteristics of high enthalpy atmospheric pressure argon and nitrogen jets produced by a high- current industrially important arc plasmatron with a vortex stabilized channel-anode (I4g/s, jet diameter at a minimum-6mm). The spectra are taken at different distances from the cathode in the 200-950nm region with a spectral resolution=3D0.01nm allowing a fine structure of vibronic bands to be essentially resolved except that due to the dublet (spin) splitting and Λ-doubling. Also derived (through the Abel inversion) are radial distributions of plasma components. The spectra obtained have been used for determining plasma composition, the electron component parameters (by atomic/ionic Stark half-widths and intensities) and the assessment of rotational and vibrational temperatures by simulating molecular bands.

  19. Simulation of the single-vibronic-level emission spectra of HAsO and DAsO

    Science.gov (United States)

    Mok, Daniel K. W.; Lee, Edmond P. F.; Dyke, John M.

    2016-05-01

    The single-vibronic-level (SVL) emission spectra of HAsO and DAsO have been simulated by electronic structure/Franck-Condon factor calculations to confirm the spectral molecular carrier and to investigate the electronic states involved. Various multi-reference (MR) methods, namely, NEVPT2 (n-electron valence state second order perturbation theory), RSPT2-F12 (explicitly correlated Rayleigh-Schrodinger second order perturbation theory), and MRCI-F12 (explicitly correlated multi-reference configuration interaction) were employed to compute the geometries and relative electronic energies for the X ˜ 1 A ' and A ˜ 1 A ″ states of HAsO. These are the highest level calculations on these states yet reported. The MRCI-F12 method gives computed T0 (adiabatic transition energy including zero-point energy correction) values, which agree well with the available experimental T0 value much better than previously computed values and values computed with other MR methods in this work. In addition, the potential energy surfaces of the X ˜ 1 A ' and A ˜ 1 A ″ states of HAsO were computed using the MRCI-F12 method. Franck-Condon factors between the two states, which include anharmonicity and Duschinsky rotation, were then computed and used to simulate the recently reported SVL emission spectra of HAsO and DAsO [R. Grimminger and D. J. Clouthier, J. Chem. Phys. 135, 184308 (2011)]. Our simulated SVL emission spectra confirm the assignments of the molecular carrier, the electronic states involved, and the vibrational structures observed in the SVL emission spectra but suggest a loss of intensity in the reported experimental spectra at the low emission energy region almost certainly due to a loss of responsivity near the cutoff region (˜800 nm) of the detector used. Computed and experimentally derived re (equilibrium) and/or r0 {the (0,0,0) vibrational level} geometries of the two states of HAsO are discussed.

  20. c2d Spitzer IRS spectra of embedded low-mass young stars: gas-phase emission lines

    CERN Document Server

    Lahuis, Fred; Jørgensen, Jes K; Blake, Geoffrey A; Evans, Neal J

    2010-01-01

    A survey of mid-IR gas-phase emission lines of H2, H2O and various atoms toward a sample of 43 embedded low-mass young stars in nearby star-forming regions is presented. The sources are selected from the Spitzer "Cores to Disks" (c2d) legacy program. The environment of embedded protostars is complex both in its physical structure (envelopes, outflows, jets, protostellar disks) and the physical processes (accretion, irradiation by UV and/or X-rays, excitation through slow and fast shocks) which take place. A key point is to spatially resolve the emission in the Spitzer-IRS spectra. An optimal extraction method is used to separate both spatially unresolved (compact, up to a few 100 AU) and spatially resolved (extended, 1000 AU or more) emission from the IRS spectra. The results are compared with the c2d disk sample and literature PDR and shock models to address the physical nature of the sources. Both compact and extended emission features are observed. Warm (Tex few 100 K) H2, observed through the pure rotatio...

  1. Mn K-edge XANES spectra of manganites measured by Kbeta emission.

    Science.gov (United States)

    García, J; Sánchez, M C; Subías, G; Blasco, J; Proietti, M G

    2001-03-01

    The electronic state of Mn atoms in mixed valence manganites has been studied by means of X-ray absorption spectroscopy at the Mn K-edge. Higher resolution than in conventional measurements has been achieved by measuring the Mn Kbeta fluorescence line. We have found a unique resonance at the edge in the XANES spectra of intermediate composition RE1-xCa(x)MnO3 samples. The features of these XANES spectra do not depend on small changes in the local structure around the Mn atom. However, the spectra of the intermediate composition samples can not be reproduced by a linear combination of REMnO3 and CaMnO3 spectra. Accordingly, the electronic state of Mn atoms in these compounds can not be considered as a mixture of Mn3+ and Mn4+ pure states.

  2. Searching for narrow absorption and emission lines in XMM-Newton spectra of gamma-ray bursts

    CERN Document Server

    Campana, S; D'Avanzo, P; Ghirlanda, G; Melandri, A; Pescalli, A; Salafia, O S; Salvaterra, R; Tagliaferri, G; Vergani, S D

    2016-01-01

    We present the results of a spectroscopic search for narrow emission and absorption features in the X-ray spectra of long gamma-ray burst (GRB) afterglows. Using XMM-Newton data, both EPIC and RGS spectra, of six bright (fluence >10^{-7} erg cm^{-2}) and relatively nearby (z=0.54-1.41) GRBs, we performed a blind search for emission or absorption lines that could be related to a high cloud density or metal-rich gas in the environ close to the GRBs. We detected five emission features in four of the six GRBs with an overall statistical significance, assessed through Monte Carlo simulations, of <3.0 sigma. Most of the lines are detected around the observed energy of the oxygen edge at ~0.5 keV, suggesting that they are not related to the GRB environment but are most likely of Galactic origin. No significant absorption features were detected. A spectral fitting with a free Galactic column density (N_H) testing different models for the Galactic absorption confirms this origin because we found an indication of an...

  3. TD-DFT Study of Absorption and Emission Spectra of 2-(2'-Aminophenyl)benzothiazole Derivatives in Water.

    Science.gov (United States)

    Manojai, Natthaporn; Daengngern, Rathawat; Kerdpol, Khanittha; Kungwan, Nawee; Ngaojampa, Chanisorn

    2017-03-01

    Reduction of aromatic azides to amines is an important property of hydrogen sulphide (H2S) which is useful in fluorescence microscopy and H2S probing in cells. The aim of this work is to study the substituent effect on the absorption and emission spectra of 2-(2'-aminophenyl)benzothiazole (APBT) in order to design APBT derivatives for the use of H2S detection. Absorption and emission spectra of APBT derivatives in aqueous environment were calculated using density functional theory (DFT) and time-dependent DFT (TD-DFT) at B3LYP/6-311+G(d,p) level. The computed results favoured the substitution of strong electron-donating group on the phenyl ring opposite to the amino group for their large Stokes' shifts and emission wavelengths of over 600 nm. Also, three designed compounds were suggested as potential candidates for the fluorescent probes. Such generalised guideline learnt from this work can also be useful in further designs of other fluorescent probes of H2S in water.

  4. Study of the structural characteristics of a group of natural silicates by means of their K{beta} emission spectra

    Energy Technology Data Exchange (ETDEWEB)

    Torres Deluigi, Maria Torres [Departamento de Fisica, Facultad de Ciencias Fisico, Matematicas y Naturales, Universidad Nacional de San Luis, Chacabuco 917, CP 5700 San Luis (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, CP C1033 AAJ, Buenos Aires (Argentina)], E-mail: charo@unsl.edu.ar; Strasser, Edgardo N. [Departamento de Geologia, Facultad de Ciencias Fisico, Matematicas y Naturales, Universidad Nacional de San Luis, Chacabuco 917, CP 5700 San Luis (Argentina); Vasconcellos, Marcos A.Z. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, CP 15051, 91501-970 Porto Alegre, RS (Brazil); Riveros, Jose A. [Facultad de Matematica, Astronomia y Fisica, Universidad Nacional de Cordoba, Medina Allende y Haya de la Torre, CP 5000 Cordoba (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Rivadavia 1917, CP C1033 AAJ, Buenos Aires (Argentina)

    2006-04-21

    In this work, the Si K{beta} and Al K{beta} emission spectra of a group of natural silicates typical of a region in San Luis (Argentina) are described qualitatively within the frame of the Molecular Orbital (MO) theory. Since these spectra come from electron transitions from valence orbitals, they offer information on the chemical bonds that are present and on the molecular orbitals involved. The spectra were obtained by means of an electron microprobe. The energies, intensities and full-width at half-maximum (FWHM) of the lines that conform the silicon and aluminium K{beta} spectra were quantified. It was observed that an increase in the number of oxygen ions shared by the tetrahedra (SiO{sub 4}){sup 4-} caused a lineal increase in the FWHM of the Si K{beta}{sub 1,3} and Al K{beta}{sub 1,3} lines. This behavior is caused by the increase of the covalent character of the Si-O and Al-O bonds with the quantity of oxygen ions shared by the adjacent tetrahedra.

  5. Practical use of corrected fluorescence excitation and emission spectra of fluorescent proteins in Förster Resonance Energy Transfer (FRET) studies

    NARCIS (Netherlands)

    Hink, M.A.; Visser, N.V.; Borst, J.W.; Hoek, van A.; Visser, A.J.W.G.

    2003-01-01

    Corrected fluorescence excitation and emission spectra have been obtained from several enhanced variants of the green fluorescent protein (EGFP) isolated from the jellyfish Aequorea victoria, blue fluorescence protein (EBFP), cyan fluorescent protein (ECFP), EGFP and yellow fluorescent protein (EYFP

  6. Practical use of corrected fluorescence excitation and emission spectra of fluorescent proteins in Förster Resonance Energy Transfer (FRET) studies

    NARCIS (Netherlands)

    Hink, M.A.; Visser, N.V.; Borst, J.W.; Hoek, van A.; Visser, A.J.W.G.

    2003-01-01

    Corrected fluorescence excitation and emission spectra have been obtained from several enhanced variants of the green fluorescent protein (EGFP) isolated from the jellyfish Aequorea victoria, blue fluorescence protein (EBFP), cyan fluorescent protein (ECFP), EGFP and yellow fluorescent protein

  7. Measurement of excitation spectra in the ${}^{12}$C$(p,d)$ reaction near the $\\eta'$ emission threshold

    CERN Document Server

    Tanaka, Y K; Fujioka, H; Ayyad, Y; Benlliure, J; Brinkmann, K -T; Friedrich, S; Geissel, H; Gellanki, J; Guo, C; Gutz, E; Haettner, E; Harakeh, M N; Hayano, R S; Higashi, Y; Hirenzaki, S; Hornung, C; Igarashi, Y; Ikeno, N; Iwasaki, M; Jido, D; Kalantar-Nayestanaki, N; Kanungo, R; Knöbel, R; Kurz, N; Metag, V; Mukha, I; Nagae, T; Nagahiro, H; Nanova, M; Nishi, T; Ong, H J; Pietri, S; Prochazka, A; Rappold, C; Reiter, M P; Rodríguez-Sánchez, J L; Scheidenberger, C; Simon, H; Sitar, B; Strmen, P; Sun, B; Suzuki, K; Szarka, I; Takechi, M; Tanihata, I; Terashima, S; Watanabe, Y N; Weick, H; Widmann, E; Winfield, J S; Xu, X; Yamakami, H; Zhao, J

    2016-01-01

    Excitation spectra of $^{11}$C were measured in the $^{12}$C$(p,d)$ reaction near the $\\eta'$ emission threshold. A proton beam extracted from the synchrotron SIS-18 at GSI with an incident energy of 2.5 GeV impinged on a carbon target. The momenta of deuterons emitted at 0 degrees were precisely measured with the fragment separator FRS operated as a spectrometer. In contrast to theoretical predictions on the possible existence of deeply bound $\\eta'$ mesic states in carbon nuclei, no distinct structures were observed associated with the formation of bound states. The spectra were analyzed to set stringent constraints on the formation cross section and on the hitherto barely-known $\\eta'$-nucleus interaction.

  8. Measurement of Excitation Spectra in the ^{12}C(p,d) Reaction near the η^{'} Emission Threshold.

    Science.gov (United States)

    Tanaka, Y K; Itahashi, K; Fujioka, H; Ayyad, Y; Benlliure, J; Brinkmann, K-T; Friedrich, S; Geissel, H; Gellanki, J; Guo, C; Gutz, E; Haettner, E; Harakeh, M N; Hayano, R S; Higashi, Y; Hirenzaki, S; Hornung, C; Igarashi, Y; Ikeno, N; Iwasaki, M; Jido, D; Kalantar-Nayestanaki, N; Kanungo, R; Knöbel, R; Kurz, N; Metag, V; Mukha, I; Nagae, T; Nagahiro, H; Nanova, M; Nishi, T; Ong, H J; Pietri, S; Prochazka, A; Rappold, C; Reiter, M P; Rodríguez-Sánchez, J L; Scheidenberger, C; Simon, H; Sitar, B; Strmen, P; Sun, B; Suzuki, K; Szarka, I; Takechi, M; Tanihata, I; Terashima, S; Watanabe, Y N; Weick, H; Widmann, E; Winfield, J S; Xu, X; Yamakami, H; Zhao, J

    2016-11-11

    Excitation spectra of ^{11}C are measured in the ^{12}C(p,d) reaction near the η^{'} emission threshold. A proton beam extracted from the synchrotron SIS-18 at GSI with an incident energy of 2.5 GeV impinges on a carbon target. The momenta of deuterons emitted at 0° are precisely measured with the fragment separator (FRS) operated as a spectrometer. In contrast to theoretical predictions on the possible existence of deeply bound η^{'}-mesic states in carbon nuclei, no distinct structures are observed associated with the formation of bound states. The spectra are analyzed to set stringent constraints on the formation cross section and on the hitherto barely known η^{'}-nucleus interaction.

  9. Identifying plant species using mid-wave infrared (2.5-6µm) and thermal infrared (8-14µm) emissivity spectra

    NARCIS (Netherlands)

    Ullah, S.; Schlerf, M.; Skidmore, A.K.; Hecker, C.

    2012-01-01

    Plant species discrimination using remote sensing is generally limited by the similarity of their reflectance spectra in the visible, NIR and SWIR domains. Laboratory measured emissivity spectra in the mid infrared (MIR; 2.5µm-6µm) and the thermal infrared (TIR; 8µm-14µm) domain of different plant s

  10. Hot topic: Innovative lactation-stage-dependent prediction of methane emissions from milk mid-infrared spectra.

    Science.gov (United States)

    Vanlierde, A; Vanrobays, M-L; Dehareng, F; Froidmont, E; Soyeurt, H; McParland, S; Lewis, E; Deighton, M H; Grandl, F; Kreuzer, M; Gredler, B; Dardenne, P; Gengler, N

    2015-08-01

    The main goal of this study was to develop, apply, and validate a new method to predict an indicator for CH4 eructed by dairy cows using milk mid-infrared (MIR) spectra. A novel feature of this model was the consideration of lactation stage to reflect changes in the metabolic status of the cow. A total of 446 daily CH4 measurements were obtained using the SF6 method on 142 Jersey, Holstein, and Holstein-Jersey cows. The corresponding milk samples were collected during these CH4 measurements and were analyzed using MIR spectroscopy. A first derivative was applied to the milk MIR spectra. To validate the novel calibration equation incorporating days in milk (DIM), 2 calibration processes were developed: the first was based only on CH4 measurements and milk MIR spectra (independent of lactation stage; ILS); the second included milk MIR spectra and DIM information (dependent on lactation stage; DLS) by using linear and quadratic modified Legendre polynomials. The coefficients of determination of ILS and DLS equations were 0.77 and 0.75, respectively, with standard error of calibration of 63g/d of CH4 for both calibration equations. These equations were applied to 1,674,763 milk MIR spectra from Holstein cows in the first 3 parities and between 5 and 365 DIM. The average CH4 indicators were 428, 444, and 448g/d by ILS and 444, 467, and 471g/d by DLS for cows in first, second, and third lactation, respectively. Behavior of the DLS indicator throughout the lactations was in agreement with the literature with values increasing between 0 and 100 DIM and decreasing thereafter. Conversely, the ILS indicator of CH4 emission decreased at the beginning of the lactation and increased until the end of the lactation, which differs from the literature. Therefore, the DLS indicator seems to better reflect biological processes that drive CH4 emissions than the ILS indicator. The ILS and DLS equations were applied to an independent data set, which included 59 respiration chamber

  11. Observation of the fine structure for rovibronic spectral lines in visible part of emission spectra of $D_2$

    CERN Document Server

    Lavrov, B P; Zhukov, A S

    2011-01-01

    For the first time the fine structure of rovibronic spectral lines in visible part of emission spectra of $D_2$ molecule has been observed. Observed splitting in visible doublets is about 0.2 cm$^{-1}$ in good accordance with previous observations in the infrared part of the spectrum ($a^3\\Sigma_g^+ \\to c^3\\Pi_u$ electronic transition) by means of FTIR and laser spectroscopy. Relative intensities of the fine structure components are in agreement with our calculations of adiabatic line strengths for Hund's case "b" coupling scheme.

  12. Neutron Capture Cross Sections and Gamma Emission Spectra from Neutron Capture on 234,236,238U Measured with DANCE

    Science.gov (United States)

    Ullmann, J. L.; Mosby, S.; Bredeweg, T. A.; Couture, A. J.; Haight, R. C.; Jandel, M.; Kawano, T.; O'Donnell, J. M.; Rundberg, R. S.; Vieira, D. J.; Wilhelmy, J. B.; Wu, C.-Y.; Becker, J. A.; Chyzh, A.; Baramsai, B.; Mitchell, G. E.; Krticka, M.

    2014-05-01

    A new measurement of the 238U(n, γ) cross section using a thin 48 mg/cm2 target was made using the DANCE detector at LANSCE over the energy range from 10 eV to 500 keV. The results confirm earlier measurements. Measurements of the gamma-ray emission spectra were also made for 238U(n, γ) as well as 234,236U(n, γ). These measurements help to constrain the radiative strength function used in the cross-section calculations.

  13. Spontaneous emission spectra and quantum light-matter interactions from a strongly coupled quantum dot metal-nanoparticle system

    DEFF Research Database (Denmark)

    Van Vlack, C.; Kristensen, Philip Trøst; Hughes, S.

    2012-01-01

    We investigate the quantum optical properties of a quantum-dot dipole emitter coupled to a finite-size metal nanoparticle using a photon Green-function technique that rigorously quantizes the electromagnetic fields. We first obtain pronounced Purcell factors and photonic Lamb shifts for both a 7......- and 20-nm-radius metal nanoparticle, without adopting a dipole approximation. We then consider a quantum-dot photon emitter positioned sufficiently near the metal nanoparticle so that the strong-coupling regime is possible. Accounting for nondipole interactions, quenching, and photon transport from...... the dot to the detector, we demonstrate that the strong-coupling regime should be observable in the far-field spontaneous emission spectrum, even at room temperature. The vacuum-induced emission spectra show that the usual vacuum Rabi doublet becomes a rich spectral triplet or quartet with two of the four...

  14. Structure and magnetic exchange in heterometallic 3d-3d transition metal triethanolamine clusters.

    Science.gov (United States)

    Langley, Stuart K; Chilton, Nicholas F; Moubaraki, Boujemaa; Murray, Keith S

    2012-01-21

    Synthetic methods are described that have resulted in the formation of seven heterometallic complexes, all of which contain partially deprotonated forms of the ligand triethanolamine (teaH(3)). These compounds are [Mn(III)(4)Co(III)(2)Co(II)(2)O(2)(teaH(2))(2)(teaH)(0.82)(dea)(3.18)(O(2)CMe)(2)(OMe)(2)](BF(4))(2)(O(2)CMe)(2)·3.18MeOH·H(2)O (1), [Mn(II)(2)Mn(III)(2)Co(III)(2)(teaH)(4)(OMe)(2)(acac)(4)](NO(3))(2)·2MeOH (2), [Mn(III)(2)Ni(II)(4)(teaH)(4)(O(2)CMe)(6)]·2MeCN (3), [Mn(III)(2)Co(II)(2)(teaH)(2)(sal)(2)(acac)(2)(MeOH)(2)]·2MeOH (4), [Mn(II)(2)Fe(III)(2)(teaH)(2)(paa)(4)](NO(3))(2)·2MeOH·CH(2)Cl(2) (5), [Mn(II)Mn(III)(2)Co(III)(2)O(teaH)(2)(dea)(Iso)(OMe)(F)(2)(Phen)(2)](BF(4))(NO(3))·3MeOH (6) and [Mn(II)(2)Mn(III)Co(III)(2)(OH)(teaH)(3)(teaH(2))(acac)(3)](NO(3))(2)·3CH(2)Cl(2) (7). All of the compounds contain manganese, combined with 3d transition metal ions such as Fe, Co and Ni. The crystal structures are described and examples of 'rods', tetranuclear 'butterfly' and 'triangular' Mn(3) cluster motifs, flanked in some cases by diamagnetic cobalt(III) centres, are presented. Detailed DC and AC magnetic susceptibility and magnetization studies, combined with spin Hamiltonian analysis, have yielded J values and identified the spin ground states. In most cases, the energies of the low-lying excited states have also been obtained. The features of note include the 'inverse butterfly' spin arrangement in 2, 4 and 5. A S = 5/2 ground state occurs, for the first time, in the Mn(III)(2)Mn(II) triangular moiety within 6, the many other reported [Mn(3)O](6+) examples having S = ½ or 3/2 ground states. Compound 7 provides the first example of a Mn(II)(2)Mn(III) triangle, here within a pentanuclear Mn(3)Co(2) cluster.

  15. 3D/3D registration of coronary CTA and biplane XA reconstructions for improved image guidance.

    Science.gov (United States)

    Dibildox, Gerardo; Baka, Nora; Punt, Mark; Aben, Jean-Paul; Schultz, Carl; Niessen, Wiro; van Walsum, Theo

    2014-09-01

    The authors aim to improve image guidance during percutaneous coronary interventions of chronic total occlusions (CTO) by providing information obtained from computed tomography angiography (CTA) to the cardiac interventionist. To this end, the authors investigate a method to register a 3D CTA model to biplane reconstructions. The authors developed a method for registering preoperative coronary CTA with intraoperative biplane x-ray angiography (XA) images via 3D models of the coronary arteries. The models are extracted from the CTA and biplane XA images, and are temporally aligned based on CTA reconstruction phase and XA ECG signals. Rigid spatial alignment is achieved with a robust probabilistic point set registration approach using Gaussian mixture models (GMMs). This approach is extended by including orientation in the Gaussian mixtures and by weighting bifurcation points. The method is evaluated on retrospectively acquired coronary CTA datasets of 23 CTO patients for which biplane XA images are available. The Gaussian mixture model approach achieved a median registration accuracy of 1.7 mm. The extended GMM approach including orientation was not significantly different (P>0.1) but did improve robustness with regards to the initialization of the 3D models. The authors demonstrated that the GMM approach can effectively be applied to register CTA to biplane XA images for the purpose of improving image guidance in percutaneous coronary interventions.

  16. MRS3D: 3D Spherical Wavelet Transform on the Sphere

    Science.gov (United States)

    Lanusse, F.; Rassat, A.; Starck, J.-L.

    2011-12-01

    Future cosmological surveys will provide 3D large scale structure maps with large sky coverage, for which a 3D Spherical Fourier-Bessel (SFB) analysis is natural. Wavelets are particularly well-suited to the analysis and denoising of cosmological data, but a spherical 3D isotropic wavelet transform does not currently exist to analyse spherical 3D data. We present a new fast Discrete Spherical Fourier-Bessel Transform (DSFBT) based on both a discrete Bessel Transform and the HEALPIX angular pixelisation scheme. We tested the 3D wavelet transform and as a toy-application, applied a denoising algorithm in wavelet space to the Virgo large box cosmological simulations and found we can successfully remove noise without much loss to the large scale structure. The new spherical 3D isotropic wavelet transform, called MRS3D, is ideally suited to analysing and denoising future 3D spherical cosmological surveys; it uses a novel discrete spherical Fourier-Bessel Transform. MRS3D is based on two packages, IDL and Healpix and can be used only if these two packages have been installed.

  17. Voro3D: 3D Voronoi tessellations applied to protein structures.

    Science.gov (United States)

    Dupuis, Franck; Sadoc, Jean-François; Jullien, Rémi; Angelov, Borislav; Mornon, Jean-Paul

    2005-04-15

    Voro3D is an original easy-to-use tool, which provides a brand new point of view on protein structures through the three-dimensional (3D) Voronoi tessellations. To construct the Voronoi cells associated with each amino acid by a number of different tessellation methods, Voro3D uses a protein structure file in the PDB format as an input. After calculation, different structural properties of interest like secondary structures assignment, environment accessibility and exact contact matrices can be derived without any geometrical cut-off. Voro3D provides also a visualization of these tessellations superimposed on the associated protein structure, from which it is possible to model a polygonal protein surface using a model solvent or to quantify, for instance, the contact areas between a protein and a ligand. The software executable file for PC using Windows 98, 2000, NT, XP can be freely downloaded at http://www.lmcp.jussieu.fr/~mornon/voronoi.html franck.dupuis@sanofi-aventis.com; jean-paul-mornon@imcp.jussieu.fr.

  18. 3D/3D registration of coronary CTA and biplane XA reconstructions for improved image guidance

    Energy Technology Data Exchange (ETDEWEB)

    Dibildox, Gerardo, E-mail: g.dibildox@erasmusmc.nl; Baka, Nora; Walsum, Theo van [Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Erasmus Medical Center, 3015 GE Rotterdam (Netherlands); Punt, Mark; Aben, Jean-Paul [Pie Medical Imaging, 6227 AJ Maastricht (Netherlands); Schultz, Carl [Department of Cardiology, Erasmus Medical Center, 3015 GE Rotterdam (Netherlands); Niessen, Wiro [Quantitative Imaging Group, Faculty of Applied Sciences, Delft University of Technology, 2628 CJ Delft, The Netherlands and Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Erasmus Medical Center, 3015 GE Rotterdam (Netherlands)

    2014-09-15

    Purpose: The authors aim to improve image guidance during percutaneous coronary interventions of chronic total occlusions (CTO) by providing information obtained from computed tomography angiography (CTA) to the cardiac interventionist. To this end, the authors investigate a method to register a 3D CTA model to biplane reconstructions. Methods: The authors developed a method for registering preoperative coronary CTA with intraoperative biplane x-ray angiography (XA) images via 3D models of the coronary arteries. The models are extracted from the CTA and biplane XA images, and are temporally aligned based on CTA reconstruction phase and XA ECG signals. Rigid spatial alignment is achieved with a robust probabilistic point set registration approach using Gaussian mixture models (GMMs). This approach is extended by including orientation in the Gaussian mixtures and by weighting bifurcation points. The method is evaluated on retrospectively acquired coronary CTA datasets of 23 CTO patients for which biplane XA images are available. Results: The Gaussian mixture model approach achieved a median registration accuracy of 1.7 mm. The extended GMM approach including orientation was not significantly different (P > 0.1) but did improve robustness with regards to the initialization of the 3D models. Conclusions: The authors demonstrated that the GMM approach can effectively be applied to register CTA to biplane XA images for the purpose of improving image guidance in percutaneous coronary interventions.

  19. Influence of the emission-reception geometry in laser-induced fluorescence spectra from turbid media.

    Science.gov (United States)

    Avrillier, S; Tinet, E; Ettori, D; Tualle, J M; Gélébart, B

    1998-05-01

    Routine clinical detection of precancerous lesions by laser-inducedautofluorescence was recently demonstrated in several medicalfields. This technique is based on the analysis of complex spectrawith overlapping broad structures. However, in biological tissues, scattering and absorption are wavelength dependent, and the observedfluorescence signals are distorted when the illumination and detectiongeometry varies, making comparison of results from different groupsdifficult. We study this phenomenon experimentally in human tissuein a simple experiment: A fiber is used for the excitation and anidentical fiber is used for reception of the signal; both fibers aremaintained in contact with the tissue. We study the distortion ofthe spectra as a function of the distance between the twofibers. For correction of the spectra we show that it is possibleto use a fast and accurate ab initio Monte Carlo simulationwhen the spectral variations of the optical properties of the mediumare known. The main advantage of this simulation is itsapplicability even for complex boundary conditions or when the sampleconsists of several layers.

  20. Quasi-similar decameter emission features appearing in the solar and jovian dynamic spectra

    Science.gov (United States)

    Litvinenko, G. V.; Shaposhnikov, V. E.; Konovalenko, A. A.; Zakharenko, V. V.; Panchenko, M.; Dorovsky, V. V.; Brazhenko, A. I.; Rucker, H. O.; Vinogradov, V. V.; Melnik, V. N.

    2016-07-01

    We investigate the dynamic spectra of the Sun and jovian decametric radiation obtained by the authors with the radio telescopes UTR-2 and URAN-2 (Kharkov, Poltava, Ukraine). We focus on the similar structures that appear on the dynamic spectra of those objects: S-bursts, drifting pairs, absorption bursts and zebra patterns. Similarity in structures allows us to assume that the plasma processes in the solar corona and in the jovian magnetosphere might have similar properties. We analyze and compare the main parameters of those structures and describe briefly some mechanisms of their generation that have already discussed in publications. We selected the mechanisms which, in our opinion, most completely and consistently explain the properties of the structures under consideration.

  1. Emission and absorption spectra of some bridged 1,5-benzodiazepines

    Science.gov (United States)

    Mellor, J. M.; Pathirana, R. N.; Stibbard, J. H. A.

    Absorption spectra in neutral and acidic media are reported for a series of bridged 1,5-benzodiazepines, which are unable to tautomerize. Comparison is made with non-bridged 1,5-benzodiazepines capable of tautomeric rearrangement. Both bridged and non-bridged 1,5-benzodiazepines are essentially non-fluorescent due to the "proximity effect" of interaction between singlet ηπ* and ππ* states of similar energy, a phenomenon previously recognised in six-membered nitrogen heterocycles.

  2. Sequencing BPS spectra

    Science.gov (United States)

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

    2016-03-01

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

  3. Sequencing BPS spectra

    Energy Technology Data Exchange (ETDEWEB)

    Gukov, Sergei [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Max-Planck-Institut für Mathematik,Vivatsgasse 7, D-53111 Bonn (Germany); Nawata, Satoshi [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Centre for Quantum Geometry of Moduli Spaces, University of Aarhus,Nordre Ringgade 1, DK-8000 (Denmark); Saberi, Ingmar [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Stošić, Marko [CAMGSD, Departamento de Matemática, Instituto Superior Técnico,Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Mathematical Institute SANU,Knez Mihajlova 36, 11000 Belgrade (Serbia); Sułkowski, Piotr [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Faculty of Physics, University of Warsaw,ul. Pasteura 5, 02-093 Warsaw (Poland)

    2016-03-02

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

  4. Characterization of high-resolution aerosol mass spectra of primary organic aerosol emissions from Chinese cooking and biomass burning

    Directory of Open Access Journals (Sweden)

    L.-Y. He

    2010-09-01

    Full Text Available Aerosol Mass Spectrometer (AMS has proved to be a powerful tool to measure submicron particulate composition with high time resolution. Factor analysis of mass spectra (MS collected worldwide by AMS demonstrates that submicron organic aerosol (OA is usually composed of several major components, such as oxygenated (OOA, hydrocarbon-like (HOA, biomass burning (BBOA, and other primary OA. In order to help interpretation of component MS from factor analysis of ambient OA datasets, AMS measurement of different primary sources is required for comparison. Such work, however, has been very scarce in the literature, especially for high resolution MS (HR-MS measurement, which performs improved characterization by separating the ions of different elemental compositions at each m/z in comparison with unit mass resolution MS (UMR-MS measurement. In this study, primary emissions from four types of Chinese cooking (CC and six types of biomass burning (BB were simulated systemically and measured using an Aerodyne High-Resolution Time-of-Flight AMS (HR-ToF-AMS. The MS of the CC emissions show high similarity with m/z 41 and m/z 55 being the highest signals; the MS of the BB emissions also show high similarity with m/z 29 and m/z 43 being the highest signals. The MS difference between the CC and BB emissions is much bigger than that between different CC (or BB types, especially for the HR-MS. The O/C ratio of OA ranges from 0.08 to 0.13 for the CC emissions while from 0.18 to 0.26 for the BB emissions. The ions of m/z 43, m/z 44, m/z 57, and m/z 60, usually used as tracer ions in AMS measurement, were examined for their HR-MS characteristics in the CC and BB emissions. Moreover, the MS of the CC and BB emissions are also used to compare with component MS from factor analysis of ambient OA datasets observed in China, as well as with other AMS measurements of primary sources in the literature. The MS

  5. Evolving mass spectra of the oxidized component of organic aerosol: results from aerosol mass spectrometer analyses of aged diesel emissions

    Directory of Open Access Journals (Sweden)

    A. M. Sage

    2007-07-01

    Full Text Available The species and chemistry responsible for secondary organic aerosol (SOA formation remain highly uncertain. Laboratory studies of the oxidation of individual, high-flux SOA precursors do not lead to particles with mass spectra (MS matching those of ambient aged organic material. And, the complexity of real organic particles challenges efforts to identify their chemical origins. We have previously hypothesized that SOA can form from the atmospheric oxidation of a large suite of precursors with varying vapor pressures. Here, we support this hypothesis by using an aerosol mass spectrometer to track the chemical evolution of diesel exhaust as it is photochemically oxidized in an environmental chamber. With explicit knowledge of the condensed-phase MS of the primary emissions from our engine, we are able to decompose each recorded MS into contributing primary and secondary spectra throughout the experiment. We find that the SOA MS becomes increasingly oxidized as a function of time, eventually reaching a final MS that closely resembles that of ambient aged organic particulate matter. This observation is consistent with the idea that lower vapor pressure, semi-volatile organic emissions can form condensable products with fewer generations of oxidation, and therefore, they form relatively less oxidized SOA very quickly.

  6. The infrared emission spectra of compositionally inhomogeneous aggregates composed of irregularly shaped constituents

    NARCIS (Netherlands)

    M. Min; J.W. Hovenier; L.B.F.M. Waters; A. de Koter

    2008-01-01

    Aims. In order to deduce properties of dust in astrophysical environments where dust growth through aggregation is high, knowledge of the way aggregated particles interact with radiation, and what information is encoded in the thermal radiation they emit, is needed. The emission characteristics are

  7. Effects of temporal laser profile on the emission spectra for underwater laser-induced breakdown spectroscopy: Study by short-interval double pulses with different pulse durations

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Ayaka, E-mail: tamura.ayaka.88m@st.kyoto-u.ac.jp; Matsumoto, Ayumu; Nishi, Naoya; Sakka, Tetsuo, E-mail: sakka.tetsuo.2a@kyoto-u.ac.jp [Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510 (Japan); Nakajima, Takashi; Ogata, Yukio H. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan); Fukami, Kazuhiro [Department of Materials Science and Engineering, Graduate School of Engineering, Kyoto University, Kyoto 606-8501 (Japan)

    2015-01-14

    We investigate the effects of temporal laser profile on the emission spectra of laser ablation plasma in water. We use short-interval (76 ns) double pulses with different pulse durations of the composing two pulses for the irradiation of underwater target. Narrow atomic spectral lines in emission spectra are obtained by the irradiation, where the two pulses are wide enough to be merged into a single-pulse-like temporal profile, while deformed spectra are obtained when the two pulses are fully separated. The behavior of the atomic spectral lines for the different pulse durations is consistent with that of the temporal profiles of the optical emission intensities of the plasma. All these results suggest that continuous excitation of the plasma during the laser irradiation for ∼100 ns is a key to obtain narrow emission spectral lines.

  8. Investigating Metal-Enrichment, Tidal Heating, and Clouds in the Emission and Transmission Spectra of GJ 436b

    Science.gov (United States)

    Morley, Caroline; Knutson, Heather; Line, Michael R.; Fortney, Jonathan J.; Marley, Mark S.; Teal, Dillon; Lupu, Roxana E.

    2016-10-01

    One of the legacies of the Kepler mission is the preponderance of planets between Earth and Neptune in radius; a major goal of atmospheric studies is to characterize planets spanning this size range. What is the range of compositions of these objects, and does these compositions correlate with planet mass (or some other property)? Do they have clouds and/or hazes in their atmospheres? How do atmospheric dynamics shape our observations? The Neptune-mass GJ 436b is one of the most-studied transiting exoplanets to date, with repeated measurements of both its thermal emission and transmission spectra. I will discuss new observations of GJ 436b's thermal emission at 3.6 and 4.5 μm, which reduce the uncertainties in estimates of GJ 436b's flux at those wavelengths and demonstrate consistency between Spitzer observations spanning more than 7 years. For the first time, we analyze the Spitzer thermal emission photometry and Hubble WFC3 transmission spectrum in tandem. I will show how we use a powerful dual-pronged modeling approach, comparing these data to both self-consistent and retrieval models. We vary the metallicity, intrinsic luminosity from tidal heating, disequilibrium chemistry, and heat redistribution. We also study the potential effect of both clouds and photochemical hazes on the spectra, but do not find strong evidence for either. The self-consistent and retrieval modeling combine to suggest that GJ 436b has a high atmospheric metallicity, with best fits at or above several hundred times solar metallicity, tidal heating warming its interior with best-fit intrinsic effective effective temperatures around 300-350 K, and disequilibrium chemistry. We suggest that Neptune-mass planets may be a more diverse class than previously imagined, with a range of metal-enhancements spanning over an order of magnitude from 50-100 to perhaps over 1000× solar metallicity. High fidelity observations with instruments like JWST will be critical for characterizing this diversity.

  9. The local dust foregrounds in the microwave sky: I. Thermal emission spectra

    CERN Document Server

    Dikarev, V; Solanki, S; Krüger, H; Krivov, A

    2009-01-01

    Analyses of the cosmic microwave background (CMB) radiation maps made by the Wilkinson Microwave Anisotropy Probe (WMAP) have revealed anomalies not predicted by the standard inflationary cosmology. In particular, the power of the quadrupole moment of the CMB fluctuations is remarkably low, and the quadrupole and octopole moments are aligned mutually and with the geometry of the Solar system. It has been suggested in the literature that microwave sky pollution by an unidentified dust cloud in the vicinity of the Solar system may be the cause for these anomalies. In this paper, we simulate the thermal emission by clouds of spherical homogeneous particles of several materials. Spectral constraints from the WMAP multi-wavelength data and earlier infrared observations on the hypothetical dust cloud are used to determine the dust cloud's physical characteristics. In order for its emissivity to demonstrate a flat, CMB-like wavelength dependence over the WMAP wavelengths (3 through 14 mm), and to be invisible in the...

  10. Interpreting the Ionization Sequence in Star-Forming Galaxy Emission-Line Spectra

    CERN Document Server

    Richardson, Chris T; Baldwin, Jack A; Hewett, Paul C; Ferland, Gary J; Crider, Anthony; Meskhidze, Helen

    2016-01-01

    High ionization star forming (SF) galaxies are easily identified with strong emission line techniques such as the BPT diagram, and form an obvious ionization sequence on such diagrams. We use a locally optimally emitting cloud model to fit emission line ratios that constrain the excitation mechanism, spectral energy distribution, abundances and physical conditions along the star-formation ionization sequence. Our analysis takes advantage of the identification of a sample of pure star-forming galaxies, to define the ionization sequence, via mean field independent component analysis. Previous work has suggested that the major parameter controlling the ionization level in SF galaxies is the metallicity. Here we show that the observed SF- sequence could alternatively be interpreted primarily as a sequence in the distribution of the ionizing flux incident on gas spread throughout a galaxy. Metallicity variations remain necessary to model the SF-sequence, however, our best models indicate that galaxies with the hig...

  11. The infrared emission spectra of compositionally inhomogeneous aggregates composed of irregularly shaped constituents

    CERN Document Server

    Min, M; Waters, L B F M; De Koter, A

    2008-01-01

    In order to deduce properties of dust in astrophysical environments where dust growth through aggregation is important, knowledge of the way aggregated particles interact with radiation, and what information is encoded in the thermal radiation they emit, is needed. The emission characteristics are determined by the size and structure of the aggregate and the composition and shape of the constituents. We thus aim at performing computations of compositionally inhomogeneous aggregates composed of irregularly shaped constituents. In addition we aim at developing an empirical recipe to compute the optical properties of such aggregates in a fast and accurate manner. We performed CDA computations for aggregates of irregularly shaped particles with various compositions. The constituents of the aggregate are assumed to be in the Rayleigh regime, and in addition we assume that the dominant interaction of the aggregate constituents is through dipole-dipole interactions. We computed the spectral structure of the emission...

  12. Evaluation of infrared emission spectra of aircraft exhaust with the FitFas software

    Directory of Open Access Journals (Sweden)

    E. Lindermeir

    Full Text Available A Fourier transform spectrometer was used to measure infrared spectra of the exhaust gas of an aircraft's jet engine. The measured spectra were modelled by use of the program FASCODE. For this simulation, the inhomogeneous gas mixture is divided into several homogenous layers which are characterized by their geometrical extents, temperatures, pressures and chemical compositions. To obtain values for the temperatures and the CO, NO, H2O and CO2 concentrations of the layers a nonlinear least-squares algorithm was implemented. The program (FITFAS not only changes the parameters to find the minimum of the squared differences between measurement and calculation; it also provides the variances and covariances of the parameters. Thus information is obtained to which parameters (besides the interesting ones must be fitted (or be accurately known. It also tells us whether or not another spectral interval is more suitable for the determination of a specific parameter.

  13. Experimental Studies of Low-Pressure Plasma Jet by Means of Langmuir Probes and Emission Spectra

    Institute of Scientific and Technical Information of China (English)

    LIU Lei; CAO Jinxiang; NIU Tianye; WANG Liang; MENG Gang; LIU Xin; YUAN Lei; WU Runhui; ZHANG Shengjun; REN Aimin

    2009-01-01

    An investigation was made into the argon plasma jet that expanded in a low-pressure vacuum chamber. The spatial distributions of the parameters of the plasma jet with different supplied powers were measured using a ten-channel Langmuir probe array. The chemical species in the plasma jet were identified by emission spectroscopy. The electron excitation temperatures at two positions, 10 cm and 50 cm downstream from the nozzle exit were calculated, respectively, by the Boltzmann plot method.

  14. Peak-Flux-Density Spectra of Large Solar Radio Bursts and Proton Emission from Flares.

    Science.gov (United States)

    1985-08-19

    3(d).- 37. Juday, R. D., and Adams, G. W. (1969) Riometer measurements, solar proton intensities and radiation dose rates, Planet. Space Sci. 17:1313...emissions radioelectriques solaires de Type IV et leur relation avec d’autres phenomenes solaires et geophys- iques, Ann.- Astrophys. 24:183. 39. Harvey, G. A...1965) 2800 megacycle per second radiation associated with Type II and Type IV solar radio bursts and the relation with other phen- omena, J

  15. Effects of quantum interference in spectra of cascade spontaneous emission from multilevel systems

    Science.gov (United States)

    Makarov, A. A.; Yudson, V. I.

    2016-12-01

    A general expression for the spectrum of cascade spontaneous emission from an arbitrary multilevel system is presented. Effects of the quantum interference of photons emitted in different transitions are analyzed. These effects are especially essential when the transition frequencies are close. Several examples are considered: (i) Three-level system; (ii) Harmonic oscillator; (iii) System with equidistant levels and equal rates of the spontaneous decay for all the transitions; (iv) Dicke superradiance model.

  16. Fluorescence of Bacteria, Pollens, and Naturally Occurring Airborne Particles: Excitation/Emission Spectra

    Science.gov (United States)

    2009-02-01

    have important effects on climate, through scattering and absorbing light, and acting as cloud condensation nuclei (17–19). Improved real-time...from polymerization and other reactions of volatile terpenes released by plants are not considered biological by at least some researchers. Humic...has a higher energy per photon absorbed , and this energy is higher than that of the photons emitted from NADH or riboflavin, but the emission is

  17. Study of medical isotope production facility stack emissions and noble gas isotopic signature using automatic gamma-spectra analysis platform

    Science.gov (United States)

    Zhang, Weihua; Hoffmann, Emmy; Ungar, Kurt; Dolinar, George; Miley, Harry; Mekarski, Pawel; Schrom, Brian; Hoffman, Ian; Lawrie, Ryan; Loosz, Tom

    2013-04-01

    The nuclear industry emissions of the four CTBT (Comprehensive Nuclear-Test-Ban Treaty) relevant radioxenon isotopes are unavoidably detected by the IMS along with possible treaty violations. Another civil source of radioxenon emissions which contributes to the global background is radiopharmaceutical production companies. To better understand the source terms of these background emissions, a joint project between HC, ANSTO, PNNL and CRL was formed to install real-time detection systems to support 135Xe, 133Xe, 131mXe and 133mXe measurements at the ANSTO and CRL 99Mo production facility stacks as well as the CANDU (CANada Deuterium Uranium) primary coolant monitoring system at CRL. At each site, high resolution gamma spectra were collected every 15 minutes using a HPGe detector to continuously monitor a bypass feed from the stack or CANDU primary coolant system as it passed through a sampling cell. HC also conducted atmospheric monitoring for radioxenon at approximately 200 km distant from CRL. A program was written to transfer each spectrum into a text file format suitable for the automatic gamma-spectra analysis platform and then email the file to a server. Once the email was received by the server, it was automatically analysed with the gamma-spectrum software UniSampo/Shaman to perform radionuclide identification and activity calculation for a large number of gamma-spectra in a short period of time (less than 10 seconds per spectrum). The results of nuclide activity together with other spectrum parameters were saved into the Linssi database. This database contains a large amount of radionuclide information which is a valuable resource for the analysis of radionuclide distribution within the noble gas fission product emissions. The results could be useful to identify the specific mechanisms of the activity release. The isotopic signatures of the various radioxenon species can be determined as a function of release time. Comparison of 133mXe and 133Xe activity

  18. Soft-excess in ULX spectra: disc emission or wind absorption?

    CERN Document Server

    Gonçalves, A C

    2006-01-01

    We assess the claim that Ultra-luminous X-ray sources (ULXs) host intermediate-mass black holes (BH) by comparing the cool disc-blackbody model with a range of other models, namelly a more complex physical model based on a power-law component slightly modified at various energies by smeared emission/absorption lines from highly-ionized gas. Our main conclusion is that the presence of a soft excess, or a soft deficit, depends entirely on the energy range to which we choose to fit the ``true'' power-law continuum; hence, we argue that those components should not be taken as evidence for accretion disc emission, nor used to infer BH masses. We speculate that bright ULXs could be in a spectral state similar to (or an extension of) the steep-power-law state of Galactic BH candidates, in which the disc is completely comptonized and not directly detectable, and the power-law emission may be modified by the surrounding, fast-moving, ionized gas.

  19. Investigating the Sensitivity of Emission Line Spectra to the Incident SED in Narrow Line Seyferts and LINERs

    Science.gov (United States)

    Greene, Christopher; Richardson, Chris T.

    2017-01-01

    This research investigates photoionization models of the Narrow Line Region (NLR) of Seyfert galaxies and Low-Ionization Nuclear Emitting Region (LINER) galaxies with the use of the astrophysical code CLOUDY. Groves et al. 2004 attempted to resolve the apparent uniformity of emission line ratios in the NLR through introducing dusty, radiation pressure-dominated photoionization models of AGN. This model assumed a simple power law relation for the Spectral Energy Distribution (SED). Grupe et al. 2010 found a correlation between αuv and αx, and by constraining αuv as a function of αx we developed a photoionization model for the ionizing spectrum of a typical Seyfert Narrow Line Region. The incident SED is based upon the spectral indices αuv, αx, αox , and the blackbody accretion disk temperature Tbb . We set the value of αox based on the average of data collected in Grupe et al. 2010, and fix the value of αuv to αx based on their linear correlation. To check the validity of our model, simulations were run across a range of blackbody accretion disk temperatures and αx, while fixing the hydrogen density, ionization parameter, and elemental abundance of clouds in the NLR. The emission lines produced by these simulations were plotted using standard diagnostic diagrams and compared to emission line data obtained from the Sloan Digital Sky Survey. Our model produces emission lines without significant variation between simulations with αx = 1.42, 1.17, and 2.19, with Tbb ranging from 104 K to 107 K, except with regard to [O I] λ6300/Hα, where our simulated spectra started to fall on the boundary between Seyferts and LINERs. This leads us to examine the ability of our photoionization model to create emission line spectra that are typical of LINERs, as debate still continues over the primary excitation mechanism for LINERs. To adjust our model to fit LINERs, we lower the value of the ionization parameter and discuss the preliminary results within the context of

  20. Predicting the stellar and non-equilibrium dust emission spectra of high-resolution simulated galaxies with DART-Ray

    CERN Document Server

    Natale, Giovanni; Tuffs, Richard J; Debattista, Victor P; Fischera, Jörg; Grootes, Meiert W

    2015-01-01

    We describe the calculation of the stochastically heated dust emission using the 3D ray-tracing dust radiative transfer code DART-Ray, which is designed to solve the dust radiative transfer problem for galaxies with arbitrary geometries. In order to reduce the time required to derive the non-equilibrium dust emission spectra from each volume element within a model, we implemented an adaptive SED library approach, which we tested for the case of axisymmetric galaxy geometries. To show the capabilities of the code, we applied DART-Ray to a high-resolution N-body+SPH galaxy simulation to predict the appearance of the simulated galaxy at a set of wavelengths from the UV to the sub-mm. We analyse the results to determine the effect of dust on the observed radial and vertical profiles of the stellar emission as well as on the attenuation and scattering of light from the constituent stellar populations. We also quantify the proportion of dust re-radiated stellar light powered by young and old stellar populations, bo...

  1. Predicting the stellar and non-equilibrium dust emission spectra of high-resolution simulated galaxies with DART-RAY

    Science.gov (United States)

    Natale, Giovanni; Popescu, Cristina C.; Tuffs, Richard. J.; Debattista, Victor P.; Fischera, Jörg; Grootes, Meiert W.

    2015-05-01

    We describe the calculation of the stochastically heated dust emission using the 3D ray-tracing dust radiative transfer code DART-RAY, which is designed to solve the dust radiative transfer problem for galaxies with arbitrary geometries. In order to reduce the time required to derive the non-equilibrium dust emission spectra from each volume element within a model, we implemented an adaptive spectral energy distribution library approach, which we tested for the case of axisymmetric galaxy geometries. To show the capabilities of the code, we applied DART-RAY to a high-resolution N-body+SPH galaxy simulation to predict the appearance of the simulated galaxy at a set of wavelengths from the UV to the sub-mm. We analyse the results to determine the effect of dust on the observed radial and vertical profiles of the stellar emission as well as on the attenuation and scattering of light from the constituent stellar populations. We also quantify the proportion of dust re-radiated stellar light powered by young and old stellar populations, both bolometrically and as a function of infrared wavelength.

  2. Early Results from the Galactic O-Star Spectroscopic Survey: C III Emission Lines in Of Spectra

    CERN Document Server

    Walborn, Nolan R; Apellaniz, Jesus Maiz; Alfaro, Emilio J; Morrell, Nidia I; Barba, Rodolfo H; Arias, Julia I; Gamen, Roberto C

    2010-01-01

    On the basis of an extensive new spectroscopic survey of Galactic O stars, we introduce the Ofc category, which consists of normal spectra with C III \\lambda\\lambda4647-4650-4652 emission lines of comparable intensity to those of the Of defining lines N III \\lambda\\lambda4634-4640-4642. The former feature is strongly peaked to spectral type O5, at all luminosity classes, but preferentially in some associations or clusters and not others. The relationships of this phenomenon to the selective C III \\lambda5696 emission throughout the normal Of domain, and to the peculiar, variable Of?p category, for which strong C III \\lambda\\lambda4647-4650-4652 emission is a defining characteristic, are discussed. Magnetic fields have recently been detected on two members of the latter category. We also present two new extreme Of?p stars, NGC 1624-2 and CPD -28^{\\circ}2561, bringing the number known in the Galaxy to five. Modeling of the behavior of these spectral features can be expected to better define the physical paramet...

  3. VizieR Online Data Catalog: Spectra of 7 Hα emission line stars in MBM 18 (Brand+ 2012)

    Science.gov (United States)

    Brand, J.; Wouterloot, J. G. A.; Magnani, L.

    2012-10-01

    Data in tabular form (wavelength and flux) are presented of the spectra of seven candidate Hα emission line stars in the direction of translucent cloud MBM 18. The data were obtained on 5 different nights in 2009 and 2010 with the 3.58-m Telescopio Nazionale Galileo (TNG; La Palma, Canary Islands, Spain). The spectra are shown in the appendix of the paper, only visible in the on line version. The spectra were taken with the low-resolution spectrograph DOLORES on the TNG, using long-slit spectroscopy. We used grism VHR-R, which covers a wavelength range of 6240-7720 Angstrom with a dispersion of 0.80Å/pix. The scale of the CCD detector is 0.252 arcsec/pixel. The observations were carried out with a slit width of 1 or 1.5 arcsec, depending on the seeing, resulting in a spectral resolution of 3.2Å and 4.8Å, respectively. To avoid problems with cosmic rays, 2 to 4 separate spectra per star were obtained. Two of the stars (Ha4 and Ha6) were observed simultaneously with another target (Ha1 and Ha5, respectively) by positioning the slit at an appropriate angle. The integration time was based on the brighter star in the slit, thus the signal-to-noise ratio for the other target is smaller than for the primary one. To allow absolute flux calibration the standard star Feige24 or Feige34 (for Ha5-Ha6) was observed immediately before or after the target observations, using the same instrumental setup as for the target observations. Flat-fielding was performed using 10 (5 for Ha5-Ha6) frames, which were uniformly illuminated by a halogen lamp. Wavelength calibration was performed using an arc-spectrum of an Ar, Ne+Hg, and Kr lamp, or a Ne+Hg (for Ha7) comparison lamp. A bias frame, to be subtracted from the other frames before analysis, was constructed from ten individual bias frames. Flat-, arc-, and bias-frames were obtained on the same day as the science observations and with the same instrumental setup. Data were reduced with the IRAF package. From all science frames a

  4. New method for measuring time-resolved spectra of lanthanide emission using square-wave excitation

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Feng [Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150080 (China); Zhao, Hua; Cai, Wei, E-mail: weicai@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Duan, Qianqian [College of Information Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Zhang, Zhiguo, E-mail: zhangzhiguo@hit.edu.cn [Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150080 (China); Laboratory of Sono- and Photo-Theranostic Technologies, Harbin Institute of Technology, Harbin 150080 (China); Cao, Wenwu, E-mail: dzk@psu.edu [Condensed Matter Science and Technology Institute, Harbin Institute of Technology, Harbin 150080 (China); Laboratory of Sono- and Photo-Theranostic Technologies, Harbin Institute of Technology, Harbin 150080 (China); Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2013-11-15

    A method using modulated continuous wave (CW) visible laser to measure time-resolved fluorescence spectra of trivalent rare-earth ions has been developed. Electro-optic modulator was used to modulate the CW pumping laser with a rise time of 2 μs. CW Nd{sup 3+} lasers were used as examples to present the method. Upconversion dynamic process of Ho{sup 3+} was studied utilizing a 532 nm CW laser. Quantum cutting dynamic process from Tb{sup 3+} to Yb{sup 3+} was analyzed by a 473 nm CW laser. This method can be applied to any CW laser such as He-Ne laser, Ar{sup +} laser, Kr{sup +} laser, Ti:sapphire laser, etc.

  5. Method of Fission Product Beta Spectra Measurements for Predicting Reactor Anti-neutrino Emission

    CERN Document Server

    Asner, D M; Campbell, L W; Greenfield, B; Kos, M S; Orrell, J L; Schram, M; VanDevender, B; Wood, 1 L S; Wootan, D W

    2014-01-01

    The nuclear fission process that occurs in the core of nuclear reactors results in unstable, neutron rich fission products that subsequently beta decay and emit electron anti-neutrinos. These reactor neutrinos have served neutrino physics research from the initial discovery of the neutrino to current precision measurements of neutrino mixing angles. The prediction of the absolute flux and energy spectrum of the emitted reactor neutrinos hinges upon a series of seminal papers based on measurements performed in the 1970s and 1980s. The steadily improving reactor neutrino measurement techniques and recent re-considerations of the agreement between the predicted and observed reactor neutrino flux motivates revisiting the underlying beta spectra measurements. A method is proposed to use an accelerator proton beam delivered to an engineered target to yield a neutron field tailored to reproduce the neutron energy spectrum present in the core of an operating nuclear reactor. Foils of the primary reactor fissionable i...

  6. Using k-alpha emission to determine fast electron spectra using the Hybrid code ZEPHYROS

    CERN Document Server

    White, Thomas; Gregori, Gianluca

    2014-01-01

    A high intensity laser-solid interaction invariably drives a non-thermal fast electron current through the target, however characterizing these fast electron distributions can prove difficult. An understanding of how these electrons propagate through dense materials is of fundamental interest and has applications relevant to fast ignition schemes and ion acceleration. Here, we utilize an upgraded version of the Hybrid code ZEPHYROS to demonstrate how the resulting k-alpha emission from such an interaction can be used as a diagnostic to obtain the characteristic temperature, divergence and total energy of the fast electron population.

  7. THEORETICAL EMISSION SPECTRA OF ATMOSPHERES OF HOT ROCKY SUPER-EARTHS

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Yuichi; Ikoma, Masahiro; Kawahara, Hajime; Nagahara, Hiroko; Kawashima, Yui [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Nakamoto, Taishi [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

    2015-03-10

    Motivated by recent detection of transiting high-density super-Earths, we explore the detectability of hot rocky super-Earths orbiting very close to their host stars. In an environment hot enough for their rocky surfaces to be molten, they would have an atmosphere composed of gas species from the magma oceans. In this study, we investigate the radiative properties of the atmosphere that is in gas/melt equilibrium with the underlying magma ocean. Our equilibrium calculations yield Na, K, Fe, Si, SiO, O, and O{sub 2} as the major atmospheric species. We compile the radiative absorption line data of those species available in the literature and calculate their absorption opacities in the wavelength region of 0.1–100 μm. Using them, we integrate the thermal structure of the atmosphere. Then, we find that thermal inversion occurs in the atmosphere because of the UV absorption by SiO. In addition, we calculate the ratio of the planetary to stellar emission fluxes during secondary eclipse, and we find prominent emission features induced by SiO at 4 μm detectable by Spitzer, and those at 10 and 100 μm detectable by near-future space telescopes.

  8. Revisiting the Infrared Spectra of Active Galactic Nuclei with a New Torus Emission Model

    CERN Document Server

    Fritz, J; Hatziminaoglou, E

    2006-01-01

    We describe improved modelling of the emission by dust in a toroidal--like structure heated by a central illuminating source within Active Galactic Nuclei (AGN). We chose a simple but realistic torus geometry, a flared disc, and a dust grain distribution function including a full range of grain sizes. The optical depth within the torus is computed in detail taking into account the different sublimation temperatures of the silicate and graphite grains, which solves previously reported inconsistencies in the silicate emission feature in type-1 AGN. We exploit this model to study the spectral energy distributions (SEDs) of 58 extragalactic (both type-1 and type-2) sources using archival optical and infrared (IR) data. We find that both AGN and starburst contributions are often required to reproduce the observed SEDs, although in a few cases they are very well fitted by a pure AGN component. The AGN contribution to the far-IR luminosity is found to be higher in type-1 sources, with all the type-2 requiring a subs...

  9. Online diagnosis of electron excitation temperature in CH4+H2 discharge plasma at atmospheric pressure by optical emission spectra

    Institute of Scientific and Technical Information of China (English)

    CUI JinHua; XU ZhenFeng; ZHANG JiaLiang; NIE QiuYue; XU GenHui; REN LongLiang

    2008-01-01

    Methane coupling under low temperature plasmas at atmospheric pressure is a green process by use of renewable sources of energy.In this study,CH4+H2 dis-charge plasma was on-line diagnosed by optical emission spectra so as to char-acterize the discharge system and to do spade work for the optimization of the technical parameters for future commercial production of methane coupling under plasmas.The study was focused on a calculation method for the online diagnosis of the electron excitation temperature in CH4+H2 discharge plasma at atmospheric pressure.The diagnostic method is easy,efficient and fairly precise.A serious er-ror in a literature was corrected during the reasoning of its series of equations formerly used to calculate electron temperatures in plasmas.

  10. Theoretical characterization of X-ray absorption, emission, and photoelectron spectra of nitrogen doped along graphene edges.

    Science.gov (United States)

    Wang, Xianlong; Hou, Zhufeng; Ikeda, Takashi; Oshima, Masaharu; Kakimoto, Masa-aki; Terakura, Kiyoyuki

    2013-01-24

    K-edge X-ray absorption (XAS), emission (XES), and photoelectron (XPS) spectra of nitrogen doped along graphene edges are systematically investigated by using first-principles methods. In this study we considered pyridinium-like, pyridine-like, cyanide-like, and amine-like nitrogens at armchair and zigzag edges and pyrrole-like nitrogen at armchair edge as well as graphite-like nitrogen at graphene interior site. Our results indicate that nitrogen configuration and its location (armchair or zigzag edge) in nitrogen-doped graphene can be identified via the spectral analysis. Furthermore, some controversial spectral features observed in experiment for N-doped graphene-like materials are unambiguously assigned. The present analysis gives an explanation to the reason why the peak assignment is usually made differently between XPS and XAS.

  11. The x-ray emission spectra of multicharged xenon ions in a gas puff laser-produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Skobelev, I.Yu.; Dyakin, V.M.; Faenov, A.Ya. [Multicharged Ion Spectra Data Center, VNIIFTRI, Mendeleevo (Russian Federation); Bartnik, A.; Fiedorowicz, H.; Jarocki, R.; Kostecki, J.; Szczurek, M. [Institute of Optoelectronics, Military University of Technology, Warsaw (Poland); Biemont, E. [Institut de Physique Nucleaire Experimentale, Universite de Liege, Liege (Belgium); Astrophysique et Spectroscopie, Universite de Mons-Hainaut, Mons (Belgium); Quinet, P. [Astrophysique et Spectroscopie, Universite de Mons-Hainaut, Mons (Belgium); Nilsen, J. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Behar, E.; Doron, R.; Mandelbaum, P.; Schwob, J.L. [Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem (Israel)

    1999-01-14

    Emission spectra of multicharged xenon ions produced by a laser gas puff are observed with high spectral resolution in the 8.5-9.5 and 17-19 A wavelength ranges. Three different theoretical methods are employed to obtain 3l-n'l'(n' = 4 to 10) wavelengths and Einstein coefficients for Ni-like Xe{sup 26+}. For the 3d-4p transitions, very good agreement is found between the experimental wavelengths and the various theoretical wavelengths. These accurate energy level measurements can be useful for studying the Ni-like xenon x-ray laser scheme. On the other hand, several intense spectral lines could not be identified as 3l-n'l' lines of Ni-like xenon, despite the very good agreement between the wavelengths and Einstein coefficients calculated for these transitions using the three different methods. (author)

  12. Online diagnosis of electron excitation temperature in CH4+H2 discharge plasma at atmospheric pressure by optical emission spectra

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Methane coupling under low temperature plasmas at atmospheric pressure is a green process by use of renewable sources of energy. In this study, CH4+H2 dis- charge plasma was on-line diagnosed by optical emission spectra so as to char- acterize the discharge system and to do spade work for the optimization of the technical parameters for future commercial production of methane coupling under plasmas. The study was focused on a calculation method for the online diagnosis of the electron excitation temperature in CH4+H2 discharge plasma at atmospheric pressure. The diagnostic method is easy, efficient and fairly precise. A serious er- ror in a literature was corrected during the reasoning of its series of equations formerly used to calculate electron temperatures in plasmas.

  13. Position Dependent Spontaneous Emission Spectra of a A-Type Atomic System Embedded in a Defective Photonic Crystal

    Institute of Scientific and Technical Information of China (English)

    S. Roshan Entezar

    2012-01-01

    We investigate the position dependent spontaneous emission spectra of a A-type three-level atom with one transition coupled to the free vacuum reservoir and the other one coupled to a double-band photonic band gap reservoir with a defect mode in the band gap. It is shown that, for the atom at the defect location, we have a two-peak spectrum with a wide dark line due to the strong coupling between the atom and the defect mode. While, when the atom is far from the defect location (or in the absence of the defect mode), the spectrum has three peaks with two dark lines due to the coupling between the atom and the photonic band gap reservoir with the largest density of states near the band edges. On the other hand, we have a four-peak spectrum for the atom at the space in between. Moreover, the average spontaneous emission spectra of the atoms uniformly embedded in high dielectric or low dielectric regions are described. It is shown that the atoms embedded in high (low) dielectric regions far from the defect location, effectively couple to the modes of the lower (upper) photonic band. However, the atoms embedded in high dielectric or low dielectric regions at the defect location, are coupled mainly to the defect modes. While, the atoms uniformly embedded in high (low) dielectric regions with a normal distance from the defect location, are coupled to both of defect and lower (upper) photonic band modes.

  14. The Early Spectra of Eta Carinae 1892 to 1941 and the Onset of Its High Excitation Emission Spectrum

    CERN Document Server

    Humphreys, Roberta M; Koppleman, Michael

    2008-01-01

    The observed behavior of eta Car from 1860 to 1940 has not been considered in most recent accounts, nor has it been explained in any quantitative model. We have used modern digital processing techniques to examine Harvard objective-prism spectra made from 1892 to 1941. Relatively high-excitation He I 4471 and [Fe III] 4658 emission, conspicuous today, were weak and perhaps absent throughout those years. Feast et al. noted this qualitative fact for other pre-1920 spectra, but we quantify it and extend it to a time only three years before Gaviola's first observations of the high-excitation features. Evidently the supply of helium-ionizing photons(lambda < 504A) grew rapidly between 1941 and 1944. The apparent scarcity of such far-UV radiation before 1944 is difficult to explain in models that employ a hot massive secondary star,} because no feasible dense wind or obscuration by dust would have hidden the photoionization caused by the proposed companion during most of its orbital period. We also discuss the q...

  15. Modelling the Emission And/or Absorption Features in the High Resolution Spectra of the Southern Binary System: HH Car

    Science.gov (United States)

    Koseoglu, Dogan; Bakış, Hicran

    2016-07-01

    High-resolution spectra (R=48000) of the southern close binary system, HH Car, has been analyzed with modern analysis techniques. Precise absolute parameters were derived from the simultaneous solution of the radial velocity, produced in this study and the light curves, published. According to the results of these analyses, the primary component is an O9 type main sequence star while the secondary component is a giant/subgiant star with a spectral type of B0. Hα emissions can be seen explicitly in the spectra of HH Car. These features were modelled using the absolute parameters of the components. Since components of HH Car are massive early-type stars, mass loss through stellar winds can be expected. This study revealed that the components of HH Car have stellar winds and the secondary component loses mass to the primary. Stellar winds and the gas stream between the components were modelled as a hot shell around the system. It is determined that the interaction between the winds and the gas stream leads to formation of a high temperature impact region.

  16. Gamma-Ray Emission Spectra as a Constraint on Calculations of 234 , 236 , 238U Neutron-Capture Cross Sections

    Science.gov (United States)

    Ullmann, J. L.; Krticka, M.; Kawano, T.; Bredeweg, T. A.; Baramsai, B.; Couture, A.; Haight, R. C.; Jandel, M.; Mosby, S.; O'Donnell, J. M.; Rundberg, R. S.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Wu, C. Y.; Chyzh, A.

    2015-10-01

    Calculations of the neutron-capture cross section at low neutron energies (10 eV through 100's of keV) are very sensitive to the nuclear level density and radiative strength function. These quantities are often poorly known, especially for radioactive targets, and actual measurements of the capture cross section are usually required. An additional constraint on the calculation of the capture cross section is provided by measurements of the cascade gamma spectrum following neutron capture. Recent measurements of 234 , 236 , 238U(n, γ) emission spectra made using the DANCE 4 π BaF2 array at the Los Alamos Neutron Science Center will be presented. Calculations of gamma-ray spectra made using the DICEBOX code and of the capture cross section made using the CoH3 code will also be presented. These techniques may be also useful for calculations of more unstable nuclides. This work was performed with the support of the U.S. Department of Energy, National Nuclear Security Administration by Los Alamos National Security, LLC (Contract DE-AC52-06NA25396) and Lawrence Livermore National Security, LLC (Contract DE-AC52-07NA2734).

  17. Using violet laser-induced chlorophyll fluorescence emission spectra for crop yield assessment of cowpea (Vigna unguiculata (L) Walp) varieties

    Science.gov (United States)

    Anderson, Benjamin; Buah-Bassuah, Paul K.; Tetteh, Jonathan P.

    2004-07-01

    The use of violet laser-induced chlorophyll fluorescence (LICF) emission spectra to monitor the growth of five varieties of cowpea in the University of Cape Coast Botanical Garden is presented. Radiation from a continuous-wave violet laser diode emitting at 396 nm through a fibre is closely incident on in vivo leaves of cowpea to excite chlorophyll fluorescence, which is detected by an integrated spectrometer with CCD readout. The chlorophyll fluorescence spectra with peaks at 683 and 731 nm were used for growth monitoring of the cowpea plants over three weeks and analysed using Gaussian spectral functions with curve fitted parameters to determine the peak positions, area under the spectral curve and the intensity ratio F683/F731. The variation in the intensity ratio of the chlorophyll bands showed sensitive changes indicating the photosynthetic activity of the cowpea varieties. A discussion of the fluorescence result as compared to conventional assessment is presented with regard to discrimination between the cowpea varieties in terms of crop yield performance.

  18. The Northern ω-Scorpiid Meteoroid Stream: Orbits and Emission Spectra

    Science.gov (United States)

    Espartero, Francisco A.; Madiedo, José M.

    2016-11-01

    We analyze the activity of the Northern ω-Scorpiid meteor shower between 2010 and 2012. For this purpose we have employed an array of low-lux CCD video cameras and spectrographs deployed at different astronomical observatories in Spain. As a result of our survey, the atmospheric trajectory and radiant position of 11 of these meteor events were obtained. The tensile strength and orbital parameters of the progenitor meteoroids have been also calculated. The calculated orbital data and the behaviour of these meteoroids in the atmosphere are compatible with an asteroidal origin of this stream. In addition, we discuss a unique emission spectrum recorded for one of these meteors. This is, to our knowledge, the first North ω-Scorpiid spectrum discussed in the scientific literature, and it has provided information about the chemical nature of the meteoroid and the progenitor body.

  19. The Northern \\omega-Scorpiid meteoroid stream: orbits and emission spectra

    CERN Document Server

    Espartero, Francisco A

    2016-01-01

    We analyze the activity of the Northern \\omega-Scorpiid meteor shower between 2010 and 2012. For this purpose we have employed an array of low-lux CCD video cameras and spectrographs deployed at different astronomical observatories in Spain. As a result of our survey, the atmospheric trajectory and radiant position of 11 of these meteor events were obtained. The tensile strength and orbital parameters of the progenitor meteoroids have been also calculated. The calculated orbital data and the behaviour of these meteoroids in the atmosphere are compatible with an asteroidal origin of this stream. In addition, we discuss a unique emission spectrum recorded for one of these meteors. This is, to our knowledge, the first North {\\omega}-Scorpiid spectrum discussed in the scientific literature, and it has provided information about the chemical nature of the meteoroid and the progenitor body.

  20. Intensity enhancement of O VI ultraviolet emission lines in solar spectra due to opacity

    CERN Document Server

    Keenan, F P; Madjarska, M S; Rose, S J; Bowler, L A; Britton, J; McCrink, L; Mathioudakis, M

    2014-01-01

    Opacity is a property of many plasmas, and it is normally expected that if an emission line in a plasma becomes optically thick, its intensity ratio to that of another transition that remains optically thin should decrease. However, radiative transfer calculations undertaken both by ourselves and others predict that under certain conditions the intensity ratio of an optically thick to thin line can show an increase over the optically thin value, indicating an enhancement in the former. These conditions include the geometry of the emitting plasma and its orientation to the observer. A similar effect can take place between lines of differing optical depth. Previous observational studies have focused on stellar point sources, and here we investigate the spatially-resolved solar atmosphere using measurements of the I(1032 A)/I(1038 A) intensity ratio of O VI in several regions obtained with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument on board the Solar and Heliospheric Observatory (...

  1. Impact of Reabsorption on the Emission Spectra and Recombination Dynamics of Hybrid Perovskite Single Crystals.

    Science.gov (United States)

    Diab, Hiba; Arnold, Christophe; Lédée, Ferdinand; Trippé-Allard, Gaëlle; Delport, Géraud; Vilar, Christèle; Bretenaker, Fabien; Barjon, Julien; Lauret, Jean-Sébastien; Deleporte, Emmanuelle; Garrot, Damien

    2017-07-06

    Understanding the surface properties of organic-inorganic lead-based perovskites is of high importance to improve the device's performance. Here, we have investigated the differences between surface and bulk optical properties of CH3NH3PbBr3 single crystals. Depth-resolved cathodoluminescence was used to probe the near-surface region on a depth of a few microns. In addition, we have studied the transmitted luminescence through thicknesses between 50 and 600 μm. In both experiments, the expected spectral shift due to the reabsorption effect has been precisely calculated. We demonstrate that reabsorption explains the important variations reported for the emission energy of single crystals. Single crystals are partially transparent to their own luminescence, and radiative transport is the dominant mechanism for propagation of the excitation in thick crystals. The transmitted luminescence dynamics are characterized by a long rise time and a lengthening of their decay due to photon recycling and light trapping.

  2. Seasonal variations of Saturn's auroral acceleration region deduced from spectra of auroral radio emissions

    Science.gov (United States)

    Kimura, T.; Lamy, L.; Tao, C.; Badman, S. V.; Cecconi, B.; Zarka, P.; Morioka, A.; Miyoshi, Y.; Kasaba, Y.; Maruno, D.; Fujimoto, M.

    2012-09-01

    Multi-instrumental surveys of Saturn's magnetosphere by Cassini have indicated that auroral radio emissions (Saturnian Kilometric Radiation, SKR), aurorae at UV and IR wavelengths and Energetic Neutral Atoms (ENA) from the inner magnetosphere exhibit periodic behavior at around Saturn's rotational period with the north-south asymmetry and seasonal variations [e.g., Gurnett et al., 2010; Mitchell et al., 2009; Nichols et al., 2010]. These rotationally periodic phenomena are suggestive of distinct magnetosphere-ionosphere coupling current systems, rotating at different periods in the northern and southern hemispheres [e.g., Andrews et al., 2010]. These phenomena suggest that the magnetosphere-ionosphere coupling process and associated energy dissipation process (aurora & SKR) are dynamically dependent on both magnetospheric rotations and long-term conditions of the magnetosphere/ionosphere.

  3. Thermal Emission Spectra of Silica-coated Basalt and Considerations for Martian Surface Mineralogy

    Science.gov (United States)

    Kraft, M. D.; Sharp, T. G.; Michalski, J. R.

    2003-01-01

    Among the most important discoveries made during the Mars Global Surveyor (MGS) mission was that the rocky materials of Mars are broadly divisible into two distinct rock types. The geological significance of this finding is dependent on the mineralogy of these rock types as well as their geographic and stratigraphic positions. Much work has yet to be done to understand these relationships and the small-scale variability of these units. For now, it is worth considering various scenarios that could have resulted in Mars global-scale mineralogical dichotomy. Such work will make clearer what must be looked for in Thermal Emission Spectrometer (TES) and Thermal Imaging Spectrometer (THEMIS) data, what to test with other data sets, and what geological processes can be considered or ruled out as we advance with interpreting Martian geologic history. Here, we suggest that exogenic coatings of secondary silica on basaltic rocks may provide a plausible explanation for the newly discovered distribution of rock types.

  4. Temperature-induced tuning of emission spectra of liquid-crystal optical microcavities

    Science.gov (United States)

    Zemánek, Pavel; Pilát, Zdeněk.; Ježek, Jan; Bernatová, Silvie; Aas, Mehdi; Kiraz, Alper; Jonáš, Alexandr

    2016-12-01

    Emulsion droplets of liquid crystals (LC) suspended in water and labeled with a suitable fluorescent dye can serve as active optofluidic microcavities, since the contrast of refractive index between the LC droplets and the surrounding aqueous medium allows excitation of whispering gallery modes (WGMs) in the droplets. In addition, such emulsion droplets can be also stably trapped in three-dimensions using optical tweezers which stabilizes the droplets while investigating their spectral characteristics. We explore various combinations of fluorescently dyed LC droplets and host liquid - surfactant systems and show that the WGM emission spectrum of an optically trapped LC droplet-based cavity can be largely and (almost) reversibly tuned by controlled changes of the ambient temperature that induce phase transitions in the LC droplets. Our results indicate feasibility of this approach for creating miniature tunable sources of coherent light.

  5. Ultraviolet emission lines of Si II in cool star and solar spectra

    CERN Document Server

    Laha, Sibasish; ferland, Gary J; Ramsbottom, Catherine A; Aggarwal, Kanti M; Ayres, Thomas R; Chatzikos, Marios; van Hoof, Peter A M; Williams, Robin J R

    2015-01-01

    Recent atomic physics calculations for Si II are employed within the Cloudy modelling code to analyse Hubble Space Telescope (HST) STIS ultraviolet spectra of three cool stars, Beta-Geminorum, Alpha-Centauri A and B, as well as previously published HST/GHRS observations of Alpha-Tau, plus solar quiet Sun data from the High Resolution Telescope and Spectrograph. Discrepancies found previously between theory and observation for line intensity ratios involving the 3s$^{2}$3p $^{2}$P$_{J}$--3s3p$^{2}$ $^{4}$P$_{J^{\\prime}}$ intercombination multiplet of Si II at 2335 Angs are significantly reduced, as are those for ratios containing the 3s$^{2}$3p $^{2}$P$_{J}$--3s3p$^{2}$ $^{2}$D$_{J^{\\prime}}$ transitions at 1816 Angs. This is primarily due to the effect of the new Si II transition probabilities. However, these atomic data are not only very different from previous calculations, but also show large disagreements with measurements, specifically those of Calamai et. al. (1993) for the intercombination lines. New m...

  6. An analysis of infrared emission spectra from the regions near the Galactic Center

    CERN Document Server

    Contini, M

    2009-01-01

    We present consistent modelling of line and continuum IR spectra in the region close to the Galactic center. The models account for the coupled effect of shocks and photoionization from an external source. The results show that the shock velocities range between 65 and 80 km/s, the pre-shock densities between 1 cm-3 in the ISM to 200 cm-3 in the filamentary structures. The pre-shock magnetic field increases from 5. 10^{-6} gauss in the surrounding ISM to ~8. 10^{-5} gauss in the Arched Filaments. The stellar temperatures are ~38000 K in the Quintuplet cluster and ~27000 K in the Arches Cluster. The ionization parameter is relatively low (0.01 near the Arches Cluster. Depletion from the gaseous phase of Si is found throughout the whole observed region, indicating the presence of silicate dust. Grains including iron, are concentrated throughout the Arched Filaments. The modelling of the continuum SED in the IR range, indicates that a component of dust at temperatures of ~100-200 K is present in the central regi...

  7. FLUORESCENCE EMISSION SPECTRA OF MARINE AND BRACKISH-WATER ECOTYPES OF FUCUS VESICULOSUS AND FUCUS RADICANS (PHAEOPHYCEAE) REVEAL DIFFERENCES IN LIGHT-HARVESTING APPARATUS(1).

    Science.gov (United States)

    Maria Gylle, Anna; Rantamäki, Susanne; Ekelund, Nils G A; Tyystjärvi, Esa

    2011-02-01

    The Bothnian Sea in the northerly part of the Baltic Sea is a geologically recent brackish-water environment, and rapid speciation is occurring in the algal community of the Bothnian Sea. We measured low-temperature fluorescence emission spectra from the Bothnian Sea and the Norwegian Sea ecotypes of Fucus vesiculosus L., a marine macroalga widespread in the Bothnian Sea. Powdered, frozen thallus was used to obtain undistorted emission spectra. The spectra were compared with spectra measured from the newly identified species Fucus radicans Bergström et L. Kautsky, which is a close relative of F. vesiculosus and endemic to the Bothnian Sea. The spectrum of variable fluorescence was used to identify fluorescence peaks originating in PSI and PSII in this chl c-containing alga. The spectra revealed much higher PSII emission, compared to PSI emission, in the Bothnian Sea ecotype of F. vesiculosus than in F. radicans or in the Norwegian Sea ecotype of F. vesiculosus. The results suggest that more light-harvesting chl a/c proteins serve PSII in the Bothnian Sea ecotype of F. vesiculosus than in the two other algal strains. Treatment of the Bothnian Sea ecotype of F. vesiculosus in high salinity (10, 20, and 35 practical salinity units) for 1 week did not lead to spectral changes, indicating that the measured features of the Bothnian Sea F. vesiculosus are stable and not simply a direct result of exposure to low salinity.

  8. Emission spectra from direct current and microwave powered Hg lamps at very high pressure

    Science.gov (United States)

    Hamady, M.; Lister, G. G.; Stafford, L.

    2013-11-01

    Discharge lamps containing mercury at pressures above 100 bar are commercially used in data projectors and television projector systems. Due to their small size, these lamps are difficult to investigate experimentally, but spectral measurements, combined with radiation transport calculations, have provided useful information on the visible spectrum. However, classical spectral line broadening theory is inadequate to describe the UV portion of the spectrum, so self-consistent modelling of these discharges is not possible at present. This paper discusses the differences between discharges containing electrodes and discharges sustained by a microwave (mw) electromagnetic field, on the basis of the experimentally measured temperature profile in an electroded discharge, and a temperature profile computed from a 1D power balance model for a microwave discharge. A model based on the ray-tracing method is employed to simulate the radiation transport in these lamps. The model has been validated by comparing the emission spectrum from dc discharge lamps with those obtained experimentally. The output flux, luminous flux, luminous efficacy, the correlated colour temperature, the chromaticity coordinates and photometric curves of the lamp were then obtained. These results were also compared with those of a theoretically calculated temperature profile for the same lamp, excited by microwave power in the TM010 mode.

  9. Single Nanoparticle Mass Spectrometry as a High Temperature Kinetics Tool: Sublimation, Oxidation, and Emission Spectra of Hot Carbon Nanoparticles.

    Science.gov (United States)

    Howder, Collin R; Long, Bryan A; Gerlich, Dieter; Alley, Rex N; Anderson, Scott L

    2015-12-17

    In single nanoparticle mass spectrometry, individual charged nanoparticles (NPs) are trapped in a quadrupole ion trap and detected optically, allowing their mass, charge, and optical properties to be monitored continuously. Previous experiments of this type probed NPs that were either fluorescent or large enough to detect by light scattering. Alternatively, small NPs can be heated to temperatures where thermally excited emission is strong enough to allow detection, and this approach should provide a new tool for measurements of sublimation and surface reaction kinetics of materials at high temperatures. As an initial test, we report a study of carbon NPs in the 20-50 nm range, heated by 10.6 μm, 532 nm, or 445 nm lasers. The kinetics for sublimation and oxidation of individual carbon NPs were studied, and a model is presented for the factors that control the NP temperature, including laser heating, and cooling by sublimation, buffer gas collisions, and radiation. The estimated NP temperatures were in the 1700-2000 K range, and the NP absorption cross sections ranged from ∼0.8 to 0.2% of the geometric cross sections for 532 nm and 10.6 μm excitation, respectively. Emission spectra of single NPs and small NP ensembles show a feature in the IR that appears to be the high energy tail of the thermal (blackbody-like) emission expected from hot particles but also a discrete feature peaking around 750 nm. Both the IR tail and 750 nm peak are observed for all particles and for both IR and visible laser excitation. No significant difference was observed between graphite and amorphous carbon NPs.

  10. Local moments and electronic correlations in Fe-based Heusler alloys: Kα x-ray emission spectra measurements

    Energy Technology Data Exchange (ETDEWEB)

    Svyazhin, Artem, E-mail: svyazhin@imp.uran.ru [M.N. Mikheev Institute of Metal Physics, Russian Academy of Sciences – Ural Division, 620990 Yekaterinburg (Russian Federation); Kurmaev, Ernst; Shreder, Elena; Shamin, Sergey [M.N. Mikheev Institute of Metal Physics, Russian Academy of Sciences – Ural Division, 620990 Yekaterinburg (Russian Federation); Sahle, Christoph J. [ESRF – The European Synchrotron, CS40220, 38043 Grenoble Cedex 9 (France)

    2016-09-15

    Heusler alloys are a property-rich class of materials, intensively investigated today from both theoretical and real-world application points of view. In this paper, we attempt to shed light on the role of electronic correlations in the Fe{sub 2}MeAl group (where Me represents all 3d elements from Ti to Ni) of Heusler alloys. For this purpose, we have investigated the local moments of iron by means of the x-ray emission spectroscopy technique. To obtain numerical values of local moments, the Kα-FWHM method has been employed for the first time. In every compound of the group, the presence of a local moment on the Fe atom was detected. As has been revealed, the values of these moments are temperature-independent, pointing to an insufficiency of a pure itinerant approach to magnetism in these alloys. We also comprehensively compare the usage of Kβ main lines and Kα spectra as tools for the probing of local moments and point out the significant advantages of the latter. - Highlights: • Local spin moments of iron in Fe{sub 2}MeAl (Me = Ti … Ni) Heusler alloys were investigated by means of x-ray emission spectroscopy. • Independence of the local moments from temperature confirms their localized nature. • A local moment value of iron in Fe{sub 2}MeAl raises with the atomic number of element Me. • The applicability of the Kα x-ray emission line for extracting local moment values of 3d elements was established.

  11. Phosphorus K β X-Ray Emission Spectra and Valence-Band Structures of Transition-Metal Phosphides and GaAs 1-xPx

    Science.gov (United States)

    Sugiura, Chikara

    1996-07-01

    The P Kβ emission spectra in fluorescence from ZrP, NbP, MoP,HfP, TaP, WP, AgP2, CdP2, Mn3P2, Cd3P2 and GaAs1-xPxfor 0.2 ≤ x ≤ 1 are measured with a high-resolutiontwo-crystal vacuum spectrometer equipped with Ge(111) crystals. Theinfluence of metal atoms appears distinctly in the P Kβemission spectra of transition-metal phosphides. The effect ofarsenic atoms appears slightly in the P Kβ emission spectraof GaAs1-xPx. The P Kβ emission spectra of AgP2,CdP2, Cd3P2 and GaAs0.6 P0.4 are compared withavailable P L2,3 emission and XPS valence-band spectra ona common energy scale. It is shown that the P 3p electronsinteract fairly with the metal d electrons in the upper partof the valence band for MP ( M = Zr, Nb, Mo, Hf, Ta, W) and Mn3P2;considerable p-d, s mixing occurs in the middle part for AgP2and in the lower part for CdP2 and Cd3P2; and the Ga 3dstates mix fairly with the P 3s states in GaAs0.6P0.4.

  12. [Two-temperature diagnostic studies by emission spectra for nonequilibrium Ti-H plasma].

    Science.gov (United States)

    Deng, Chun-feng; Lu, Biao; Wu, Chun-lei; Wang, Yi-fu; Wen, Zhong-wei

    2014-12-01

    Using the T-H solid solution made by titanium absorbed hydrogen as the cathode, the Ti-H plasma produced by the pulsed vacuum are ion source was nonequilibrium: it contained both the component of titanium and hydrogen; there existed gradient in the radiaL, the horizontal and the time. As a result, it could not be described by a single temperature. The present paper assumed that the subsystem consisting of electrons and the subsystem consisting of other heavy particles reached equilibrium respectively, meaning that the Ti-H plasma was described by the two temperatures as electron temperature and heavy ion temperature, it was non-equilibrium two-temperature plasma Using Culdberg-Waage dissociation equation to describe the molecular dissociation process in the system, using Saha ionization equation to describe the atomic ionization process, combining plasma's charge quasi-neutral condition and introducing atomic emission spectroscopy as a plasma diagnostic method which would not interfere the plasma at the same time; the temperature and the particle number density of the Ti-H plasma were diagnosed. Using MATLAB as a tool, both the titanium atoms and monovalent titanium ions' ionization were considered, and the calculated results showed that with the electtron density determined by the Stark broadening of spectral lines in advance, except the heavy particle temperature and the hydrogen number density, the Ti-H plasma's parameters could be diagnosed fairly accurately; the accuracy of the electron density values had a great effect on the calculation results; if the heavy particle temperature could be determined in advance, the temperature and the particle number density of the Ti-H plasma could be accurately analyzed quantitatively.

  13. The effects of consistent chemical kinetics calculations on the pressure-temperature profiles and emission spectra of hot Jupiters

    Science.gov (United States)

    Drummond, B.; Tremblin, P.; Baraffe, I.; Amundsen, D. S.; Mayne, N. J.; Venot, O.; Goyal, J.

    2016-10-01

    In this work we investigate the impact of calculating non-equilibrium chemical abundances consistently with the temperature structure for the atmospheres of highly-irradiated, close-in gas giant exoplanets. Chemical kinetics models have been widely used in the literature to investigate the chemical compositions of hot Jupiter atmospheres which are expected to be driven away from chemical equilibrium via processes such as vertical mixing and photochemistry. All of these models have so far used pressure-temperature (P-T) profiles as fixed model input. This results in a decoupling of the chemistry from the radiative and thermal properties of the atmosphere, despite the fact that in nature they are intricately linked. We use a one-dimensional radiative-convective equilibrium model, ATMO, which includes a sophisticated chemistry scheme to calculate P-T profiles which are fully consistent with non-equilibrium chemical abundances, including vertical mixing and photochemistry. Our primary conclusion is that, in cases of strong chemical disequilibrium, consistent calculations can lead to differences in the P-T profile of up to 100 K compared to the P-T profile derived assuming chemical equilibrium. This temperature change can, in turn, have important consequences for the chemical abundances themselves as well as for the simulated emission spectra. In particular, we find that performing the chemical kinetics calculation consistently can reduce the overall impact of non-equilibrium chemistry on the observable emission spectrum of hot Jupiters. Simulated observations derived from non-consistent models could thus yield the wrong interpretation. We show that this behaviour is due to the non-consistent models violating the energy budget balance of the atmosphere.

  14. Deriving the Extinction to Young Stellar Objects using [Fe II] Near-infrared Emission Lines: Prescriptions from GIANO High-resolution Spectra

    Science.gov (United States)

    Pecchioli, T.; Sanna, N.; Massi, F.; Oliva, E.

    2016-07-01

    The near-infrared (NIR) emission lines of Fe+ at 1.257, 1.321, and 1.644 μm share the same upper level; their ratios can then be exploited to derive the extinction to a line emitting region once the relevant spontaneous emission coefficients are known. This is commonly done, normally from low-resolution spectra, in observations of shocked gas from jets driven by Young Stellar Objects. In this paper we review this method, provide the relevant equations, and test it by analyzing high-resolution (R ∼ 50,000) NIR spectra of two young stars, namely the Herbig Be star HD 200775 and the Be star V1478 Cyg, which exhibit intense emission lines. The spectra were obtained with the new GIANO echelle spectrograph at the Telescopio Nazionale Galileo. Notably, the high-resolution spectra allowed checking the effects of overlapping telluric absorption lines. A set of various determinations of the Einstein coefficients are compared to show how much the available computations affect extinction derivation. The most recently obtained values are probably good enough to allow reddening determination within 1 visual mag of accuracy. Furthermore, we show that [Fe ii] line ratios from low-resolution pure emission-line spectra in general are likely to be in error due to the impossibility to properly account for telluric absorption lines. If low-resolution spectra are used for reddening determinations, we advice that the ratio 1.644/1.257, rather than 1.644/1.321, should be used, being less affected by the effects of telluric absorption lines.

  15. Spectral and spatial resolution of the 12.8 micron Ne 2 emission from the galactic center. [astronomical spectroscopy/emission spectra, radio sources (astronomy)

    Science.gov (United States)

    Wollman, E. R.; Geballe, T. R.; Lacy, J. H.; Townes, C. H.; Rank, D. M.

    1975-01-01

    High-resolution spectra of the Ne II 12.8 micron fine-structure line in emission from the galactic center cloud Sgr A West show a line-center LSR radial velocity of + 75 + or - 20 km/sec. and a velocity dispersion of about 200 km/sec. The line has been observed with spectral resolution as high as 0.10/cm and spatial resolution as high as 8 sec. This appears to provide a direct measurement of conditions in the 45 sec. ionized region at the galactic center. The radial velocity and dispersion are more-or-less independent of position and indicate that events as recent as the last 4 million years have given the ionized gas a systematic motion with respect to the massive stellar component of material at the galactic center. An upper limit for the mass approximately equal to four million times the solar mass was obtained from the velocity distribution, with the mass located within 0.8 parsecs of the galactic center.

  16. Spitzer Secondary Eclipse Observations of Five Cool Gas Giant Planets and Empirical Trends in Cool Planet Emission Spectra

    CERN Document Server

    Kammer, Joshua A; Line, Michael R; Fortney, Jonathan J; Deming, Drake; Burrows, Adam; Cowan, Nicolas B; Triaud, Amaury H M J; Agol, Eric; Desert, Jean-Michel; Fulton, Benjamin J; Howard, Andrew W; Laughlin, Gregory P; Lewis, Nikole K; Morley, Caroline V; Moses, Julianne I; Showman, Adam P; Todorov, Kamen O

    2015-01-01

    In this work we present Spitzer 3.6 and 4.5 micron secondary eclipse observations of five new cool (<1200 K) transiting gas giant planets: HAT-P-19b, WASP-6b, WASP-10b, WASP-39b, and WASP-67b. We compare our measured eclipse depths to the predictions of a suite of atmosphere models and to eclipse depths for planets with previously published observations in order to constrain the temperature- and mass-dependent properties of gas giant planet atmospheres. We find that the dayside emission spectra of planets less massive than Jupiter require models with efficient circulation of energy to the night side and/or increased albedos, while those with masses greater than that of Jupiter are consistently best-matched by models with inefficient circulation and low albedos. At these relatively low temperatures we expect the atmospheric methane to CO ratio to vary as a function of metallicity, and we therefore use our observations of these planets to constrain their atmospheric metallicities. We find that the most massi...

  17. Diagnosis of lubricating oil by evaluating cyanide and carbon molecular emission lines in laser induced breakdown spectra

    Science.gov (United States)

    Elnasharty, I. Y.; Kassem, A. K.; Sabsabi, M.; Harith, M. A.

    2011-08-01

    To prevent engine failure it is essential to change lubricating oil regularly before it loses its protective properties. It is also necessary to monitor the physical and chemical conditions of the oil to reliably determine the optimum oil-change intervals. The present work focuses on studying evolution of the cyanide (CN) and carbon (C 2) molecular spectral emission lines in the laser induced breakdown spectra of lubricating oil as a function of its consumption. The intensities of these molecular bands have been taken as indicator of engine oil degradation at certain mileage. Furthermore, the percentage of decay of CN and C 2 integral intensity values at the corresponding mileage was calculated in order to relate it to the degree of consumption of the motor oil. Such percentage decay of the CN and C 2 integral intensities have been found to increase gradually with increasing mileage which is accompanied with increasing depletion of engine oil. The results of using LIBS technique in the present measurements proved that it is possible to have a direct, straightforward and easy method for prediction of lubricating oil degree of consumption. This may facilitate scheduling the proper time and/or mileage intervals for changing the oil to avoid any possibility of engine failure.

  18. Absolute Time-Resolved Emission of Non-LTE L-Shell Spectra from Ti-Doped Aerogels

    Energy Technology Data Exchange (ETDEWEB)

    Back,C.; Feldman, U.; Weaver, J.; Seely, J.; Constantin, C.; Holland, G.; Lee, R.; Chung, H.; Scott, H.

    2006-01-01

    Outstanding discrepancies between data and calculations of laser-produced plasmas in recombination have been observed since the 1980s. Although improvements in hydrodynamic modeling may reduce the discrepancies, there are indications that non-LTE atomic kinetics may be the dominant cause. Experiments to investigate non-LTE effects were recently performed at the NIKE KrF laser on low-density Ti-doped aerogels. The laser irradiated a 2 mm diameter, cylindrical sample of various lengths with a 4-ns square pulse to create a volumetrically heated plasma. Ti L-shell spectra spanning a range of 0.47-3 keV were obtained with a transmission grating coupled to Si photodiodes. The diagnostic can be configured to provide 1-dimensional spatial resolution at a single photon energy, or 18 discrete energies with a resolving power, {gamma}/{delta}{gamma} of 3-20. The data are examined and compared to calculations to develop absolute emission measurements that can provide new tests of the non-LTE physics.

  19. Absolute, time-resolved emission of non-LTE L-shell spectra from Ti-doped aerogels

    Energy Technology Data Exchange (ETDEWEB)

    Back, C.A. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States)]. E-mail: tinaback@llnl.gov; Feldman, U. [Artep Inc. 2922 Excelsior Ct., Ellicott City, MD 21042 (United States); Weaver, J.L. [Naval Research Laboratory, 4555 Overlook Drive, SW, Washington DC 20375 (United States); Seely, J.F. [Naval Research Laboratory, 4555 Overlook Drive, SW, Washington DC 20375 (United States); Constantin, C. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States); Holland, G. [Naval Research Laboratory, 4555 Overlook Drive, SW, Washington DC 20375 (United States); Lee, R.W. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States); Chung, H.-K. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States); Scott, H.A. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States)

    2006-05-15

    Outstanding discrepancies between data and calculations of laser-produced plasmas in recombination have been observed since the 1980s. Although improvements in hydrodynamic modeling may reduce the discrepancies, there are indications that non-LTE atomic kinetics may be the dominant cause. Experiments to investigate non-LTE effects were recently performed at the NIKE KrF laser on low-density Ti-doped aerogels. The laser irradiated a 2mm diameter, cylindrical sample of various lengths with a 4-ns square pulse to create a volumetrically heated plasma. Ti L-shell spectra spanning a range of 0.47-3keV were obtained with a transmission grating coupled to Si photodiodes. The diagnostic can be configured to provide 1-dimensional spatial resolution at a single photon energy, or 18 discrete energies with a resolving power, {lambda}/{delta}{lambda} of 3-20. The data are examined and compared to calculations to develop absolute emission measurements that can provide new tests of the non-LTE physics.

  20. Research as a guide for curriculum development: An example from introductory spectroscopy. II. Addressing student difficulties with atomic emission spectra

    Science.gov (United States)

    Ivanjek, L.; Shaffer, P. S.; McDermott, L. C.; Planinic, M.; Veza, D.

    2015-02-01

    This is the second of two closely related articles (Paper I and Paper II) that together illustrate how research in physics education has helped guide the design of instruction that has proved effective in improving student understanding of atomic spectroscopy. Most of the more than 1000 students who participated in this four-year investigation were science majors enrolled in the introductory calculus-based physics course at the University of Washington (UW) in Seattle, WA, USA. The others included graduate and undergraduate teaching assistants at UW and physics majors in introductory and advanced physics courses at the University of Zagreb, Zagreb, Croatia. About half of the latter group were preservice high school physics teachers. Paper I describes how several conceptual and reasoning difficulties were identified among university students as they tried to relate a discrete line spectrum to the energy levels of atoms in a light source. This second article (Paper II) illustrates how findings from this research informed the development of a tutorial that led to improvement in student understanding of atomic emission spectra.

  1. High resolution catalogue of emission lines in the spectra of comet C/2002 C1 Ikeya-Zhang

    Science.gov (United States)

    Capria, M. T.; Cremonese, G.; de Sanctis, M. C.; Buzzoni, A.

    2003-04-01

    The comet C/2002 C1 Ikeya-Zhang was observed at the Telescopio Nazionale Galileo in Canary Islands with the echelle spectrograph SARG during the night 19-20 of April 2002. One echelle spectrum composed by 55 orders covering the spectral range from 462 to 792 nm with R=57000 was acquired. The observations were performed in the frame of a program aimed to collect, catalogue and identify cometary emission lines in the optical part of the spectral range. In this range many important lines of daughters molecules and ions can be found; most of these lines were detected many times with low resolution spectroscopy, but the cataloguing with high resolution spectroscopy was done until now for few comets, and many lines still remain unidentified. We present here a first version of our catalogue, in which the line identification, based on wavelength coincidence only, is made using as starting line lists the ones compiled by Brown et al. [1] and Cochran and Cochran [2]. The O(1S) and O(1D) metastable lines are also clearly visible in our spectra and well separated from the other cometary and telluric lines, so we present also a preliminary estimate of the ratio of the green and red lines. [1] M.E. Brown et al. (1996) AJ, 112. [2] A. Cochran and D. Cochran (2002) Icarus, 157.

  2. Physical properties, transmission and emission spectra of the WASP-19 planetary system from multi-colour photometry

    CERN Document Server

    Mancini, L; Chen, G; Tregloan-Reed, J; Fortney, J J; Southworth, J; Tan, T G; Burgdorf, M; Novati, S Calchi; Dominik, M; Fang, X -S; Finet, F; Gerner, T; Hardis, S; Hinse, T C; Jorgensen, U G; Liebig, C; Nikolov, N; Ricci, D; Schaefer, S; Schoenebeck, F; Skottfelt, J; Wertz, O; Alsubai, K A; Bozza, V; Browne, P; Dodds, P; Gu, S -H; Harpsoe, K; Henning, Th; Hundertmark, M; Jessen-Hansen, J; Kains, N; Kerins, E; Kjeldsen, H; Lund, M N; Lundkvist, M; Madhusudhan, N; Mathiasen, M; Penny, M T; Proft, S; Rahvar, S; Sahu, K; Scarpetta, G; Snodgrass, C; Surdej, J

    2013-01-01

    We present new ground-based, multi-colour, broad-band photometric measurements of the physical parameters, transmission and emission spectra of the transiting extrasolar planet WASP-19b. The measurements are based on observations of 8 transits and four occultations using the 1.5m Danish Telescope, 14 transits at the PEST observatory, and 1 transit observed simultaneously through four optical and three near-infrared filters, using the GROND instrument on the ESO 2.2m telescope. We use these new data to measure refined physical parameters for the system. We find the planet to be more bloated and the system to be twice as old as initially thought. We also used published and archived datasets to study the transit timings, which do not depart from a linear ephemeris. We detected an anomaly in the GROND transit light curve which is compatible with a spot on the photosphere of the parent star. The starspot position, size, spot contrast and temperature were established. Using our new and published measurements, we as...

  3. Research as a guide for curriculum development: An example from introductory spectroscopy. I. Identifying student difficulties with atomic emission spectra

    Science.gov (United States)

    Ivanjek, L.; Shaffer, P. S.; McDermott, L. C.; Planinic, M.; Veza, D.

    2015-01-01

    This is the first of two closely related articles (Paper I and Paper II) that together illustrate how research in physics education has helped guide the design of instruction that has proved effective in improving student understanding of atomic spectroscopy. Most of the more than 1000 students who participated in this four-year investigation were science majors enrolled in the introductory calculus-based physics course at the University of Washington (UW) in Seattle, WA, USA. The others included graduate and undergraduate teaching assistants at UW and physics majors in introductory and advanced physics courses at the University of Zagreb, Zagreb, Croatia. About half of the latter group were preservice high school physics teachers. This article (Paper I) describes how several serious conceptual and reasoning difficulties were identified among students as they tried to relate a discrete line spectrum to the energy levels of atoms in a light source. Paper II illustrates how findings from this research informed the development of a tutorial that led to significant improvement in student understanding of atomic emission spectra.

  4. Discovery of Rubidium, Cadmium, and Germanium Emission Lines in the Near-Infrared Spectra of Planetary Nebulae

    CERN Document Server

    Sterling, N C; Kaplan, Kyle F; Bautista, Manuel

    2016-01-01

    We identify [Rb IV] 1.5973 and [Cd IV] 1.7204 micron emission lines in high-resolution (R=40,000) near-infrared spectra of the planetary nebulae (PNe) NGC 7027 and IC 5117, obtained with the IGRINS spectrometer on the 2.7-m telescope at McDonald Observatory. We also identify [Ge VI] 2.1930 $\\mu$m in NGC 7027. Alternate identifications for these features are ruled out based on the absence of other multiplet members and/or transitions with the same upper levels. Ge, Rb, and Cd can be enriched in PNe by s-process nucleosynthesis during the asymptotic giant branch (AGB) stage of evolution. To determine ionic abundances, we calculate [Rb IV] collision strengths and use approximations for those of [Cd IV] and [Ge VI]. Our identification of [Rb IV] 1.5973 $\\mu$m is supported by the agreement between Rb3+/H+ abundances found from this line and the 5759.55 A feature in NGC 7027. Elemental Rb, Cd, and Ge abundances are derived with ionization corrections based on similarities in ionization potential ranges between the ...

  5. DETECTION OF BROAD Hα EMISSION LINES IN THE LATE-TIME SPECTRA OF A HYDROGEN-POOR SUPERLUMINOUS SUPERNOVA

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Lin; Masci, F. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Quimby, R. [Department of Astronomy, San Diego State University, San Diego, CA 92182 (United States); Ofek, E.; Gal-Yam, A.; Vreeswijk, P. M.; Leloudas, G.; Cia, A. de; Yaron, O. [Department of Particle Physics and Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100 (Israel); Mazzali, P. [Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Perley, D. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Cenko, S. B. [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Cao, Y.; Kulkarni, S. R. [Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States); Nugent, P. E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Rebbapragada, Umaa D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Woźniak, P. R., E-mail: lyan@ipac.caltech.edu [Space and Remote Sensing, ISR-2, MS-B244 Los Alamos National Laboratory Los Alamos, NM 87545 (United States)

    2015-12-01

    iPTF13ehe is a hydrogen-poor superluminous supernova (SLSN) at z = 0.3434, with a slow-evolving light curve and spectral features similar to SN2007bi. It rises in 83–148 days to reach a peak bolometric luminosity of ∼1.3 × 10{sup 44} erg s{sup −1}, then decays slowly at 0.015 mag day{sup −1}. The measured ejecta velocity is ∼ 13,000 km s{sup −1}. The inferred explosion characteristics, such as the ejecta mass (70–220 M{sub ⊙}), and the total radiative and kinetic energy (E{sub rad} ∼ 10{sup 51} erg, E{sub kin} ∼ 2 × 10{sup 53} erg), are typical of slow-evolving H-poor SLSN events. However, the late-time spectrum taken at +251 days (rest, post-peak) reveals a Balmer Hα emission feature with broad and narrow components, which has never been detected before among other H-poor SLSNe. The broad component has a velocity width of ∼4500 km s{sup −1} and a ∼300 km s{sup −1} blueward shift relative to the narrow component. We interpret this broad Hα emission with a luminosity of ∼2 × 10{sup 41} erg s{sup −1} as resulting from the interaction between the supernova ejecta and a discrete H-rich shell, located at a distance of ∼4 × 10{sup 16} cm from the explosion site. This interaction causes the rest-frame r-band LC to brighten at late times. The fact that the late-time spectra are not completely absorbed by the shock-ionized H-shell implies that its Thomson scattering optical depth is likely ≤1, thus setting upper limits on the shell mass ≤30 M{sub ⊙}. Of the existing models, a Pulsational Pair Instability supernova model can naturally explain the observed 30 M{sub ⊙} H-shell, ejected from a progenitor star with an initial mass of (95–150) M{sub ⊙} about 40 years ago. We estimate that at least ∼15% of all SLSNe-I may have late-time Balmer emission lines.

  6. Determination of size and bandgap distributions of Si nanoparticles from photoluminescence excitation and emission spectra in n-type stain etched porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Rustamov, F.A., E-mail: farhad.rustamov@bsu.az; Darvishov, N.H.; Bagiev, V.E.; Mamedov, M.Z.; Bobrova, E.Y.; Qafarova, H.O.

    2014-10-15

    The photoluminescence excitation and emission spectra of n-type stain etched porous silicon layers were investigated. From these spectra the average values of optical bandgap and photoluminescence peak position were determined. Based on these experimental data, the photoluminescence emission spectra of porous silicon were analyzed by the phenomenological theory and the fitting parameters of the theory were defined. The size and bandgap distributions of silicon nanoparticles were determined and their mean values were calculated. It was found that the investigated PS samples are the ensemble of nanoparticles with size between 1.5 nm and 2.8 nm and a bandgap from 2 eV to 3.2 eV distributed with different probabilities depending on the formation time of porous silicon. It is shown that with increasing formation time, the average size of nanocrystals is slightly increasing, while the average bandgap is slightly narrowing. - Highlights: • Stain etched n-type porous silicon layers were formed in modified solution. • Joint theoretical analysis of excitation and emission spectra was performed. • Size and bandgap distributions of nanocrystals were determined. • Mean values of nanocrystal size and bandgap were determined.

  7. Deriving the extinction to young stellar objects using [FeII] near-infrared emission lines. Prescriptions from GIANO high-resolution spectra

    CERN Document Server

    Pecchioli, Tommaso; Massi, Fabrizio; Oliva, Ernesto

    2016-01-01

    The near-infrared emission lines of Fe$^{+}$ at 1.257, 1.321, and 1.644 $\\mu$m share the same upper level; their ratios can then be exploited to derive the extinction to a line emitting region once the relevant spontaneous emission coefficients are known. This is commonly done, normally from low-resolution spectra, in observations of shocked gas from jets driven by Young Stellar Objects. In this paper we review this method, provide the relevant equations, and test it by analyzing high-resolution ($R \\sim 50000$) near-infrared spectra oftwo young stars, namely the Herbig Be star HD 200775 and the Be star V1478 Cyg, which exhibit intense emission lines. The spectra were obtained with the new GIANO echelle spectrograph at the Telescopio Nazionale Galileo. Notably, the high-resolution spectra allowed checking the effects of overlapping telluric absorption lines. A set of various determinations of the Einstein coefficients are compared to show how much the available computations affect extinction derivation. The m...

  8. Correcting for variable laser-target distances of laser-induced breakdown spectroscopy measurements with ChemCam using emission lines of Martian dust spectra

    Science.gov (United States)

    Melikechi, N.; Mezzacappa, A.; Cousin, A.; Lanza, N. L.; Lasue, J.; Clegg, S. M.; Berger, G.; Wiens, R. C.; Maurice, S.; Tokar, R. L.; Bender, S.; Forni, O.; Breves, E. A.; Dyar, M. D.; Frydenvang, J.; Delapp, D.; Gasnault, O.; Newsom, H.; Ollila, A. M.; Lewin, E.; Clark, B. C.; Ehlmann, B. L.; Blaney, D.; Fabre, C.

    2014-06-01

    As part of the Mars Science Laboratory, the ChemCam instrument acquires remote laser induced breakdown spectra at distances that vary between 1.56 m and 7 m. This variation in distance affects the intensities of the measured LIBS emission lines in non-trivial ways. To determine the behavior of a LIBS emission line with distance, it is necessary to separate the effects of many parameters such as laser energy, laser spot size, target homogeneity, and optical collection efficiency. These parameters may be controlled in a laboratory on Earth but for field applications or in space this is a challenge. In this paper, we show that carefully selected ChemCam LIBS emission lines acquired from the Martian dust can be used to build an internal proxy spectroscopic standard. This in turn, allows for a direct measurement of the effects of the distance of various LIBS emission lines and hence can be used to correct ChemCam LIBS spectra for distance variations. When tested on pre-launch LIBS calibration data acquired under Martian-like conditions and with controlled and well-calibrated targets, this approach yields much improved agreement between targets observed at various distances. This work lays the foundation for future implementation of automated routines to correct ChemCam spectra for differences caused by variable distance.

  9. DISCOVERY OF RUBIDIUM, CADMIUM, AND GERMANIUM EMISSION LINES IN THE NEAR-INFRARED SPECTRA OF PLANETARY NEBULAE

    Energy Technology Data Exchange (ETDEWEB)

    Sterling, N. C. [Department of Physics, University of West Georgia, 1601 Maple Street, Carrollton, GA 30118 (United States); Dinerstein, Harriet L.; Kaplan, Kyle F. [Department of Astronomy, University of Texas, 2515 Speedway, C1400, Austin, TX 78712-1205 (United States); Bautista, Manuel A., E-mail: nsterlin@westga.edu, E-mail: harriet@astro.as.utexas.edu, E-mail: kfkaplan@astro.as.utexas.edu, E-mail: manuel.bautista@wmich.edu [Department of Physics, Western Michigan University, Kalamazoo, MI 49008 (United States)

    2016-03-01

    We identify [Rb iv] 1.5973 and [Cd iv] 1.7204 μm emission lines in high-resolution (R = 40,000) near-infrared spectra of the planetary nebulae (PNe) NGC 7027 and IC 5117, obtained with the Immersion GRating INfrared Spectrometer (IGRINS) on the 2.7 m telescope at McDonald Observatory. We also identify [Ge vi] 2.1930 μm in NGC 7027. Alternate identifications for these features are ruled out based on the absence of other multiplet members and/or transitions with the same upper levels. Ge, Rb, and Cd can be enriched in PNe by s-process nucleosynthesis during the asymptotic giant branch stage of evolution. To determine ionic abundances, we calculate [Rb iv] collision strengths and use approximations for those of [Cd iv] and [Ge vi]. Our identification of [Rb iv] 1.5973 μm is supported by the agreement between Rb{sup 3+}/H{sup +} abundances found from this line and the 5759.55 Å feature in NGC 7027. Elemental Rb, Cd, and Ge abundances are derived with ionization corrections based on similarities in ionization potential ranges between the detected ions and O and Ne ionization states. Our analysis indicates abundances 2–4 times solar for Rb and Cd in both nebulae. Ge is subsolar in NGC 7027, but its abundance is uncertain due to the large and uncertain ionization correction. The general consistency of the measured relative s-process enrichments with predictions from models appropriate for these PNe (2.0–2.5 M{sub ⊙}, [Fe/H] = −0.37) demonstrates the potential of using PN compositions to test s-process nucleosynthesis models.

  10. Non-intrusive measurement of emission indices. A new approach to the evaluation of infrared spectra emitted by aircraft engine exhaust gases

    Energy Technology Data Exchange (ETDEWEB)

    Lindermeir, E.; Haschberger, P.; Tank, V. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Optoelektronik

    1997-12-31

    A non-intrusive method is used to determine the emission indices of a research aircraft`s engine in-flight. The principle is based on the Fourier Transform Infrared Spectrometer MIROR which was specifically designed and built for operation aboard aircrafts. This device measures the spectrum of the infrared radiation emitted by the hot exhaust gas under cruise conditions. From these spectra mixing ratios and emission indices can be derived. An extension to previously applied evaluation schemes is proposed: Whereas formerly the plume was assumed a homogeneous layer of gas, temperature and concentration profiles are now introduced to the evaluation procedure. (author) 5 refs.

  11. Searching double-peaked emission line profiles in the spectra of galaxies through the symmetry of the cross-correlation function

    CERN Document Server

    Garcia-Lorenzo, B

    2012-01-01

    The presence of double-peaked/multicomponent emission line profiles in spectra of galaxies is commonly done by visual inspection. However, the identification of complex emission line profiles by eye is unapproachable for large databases such as the Sloan Digital Sky Survey (SDSS) or the integral field spectroscopy surveys of galaxies (e.g. CALIFA or MaNGA). We describe a quick method involving the cross-correlation technique for detecting the presence of complex (double-peaked or multiple components) profiles in the spectra of galaxies, deriving simultaneously a first estimation of the velocity dispersions and radial velocities of the dominant gaseous component. We illustrate the proposed procedure with the well-known complex [OIII]4959,5007 profiles of the central region of NGC1068.

  12. Revealing discriminating power of the elements in edible sea salts: Line-intensity correlation analysis from laser-induced plasma emission spectra

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yonghoon, E-mail: yhlee@mokpo.ac.kr [Department of Chemistry, Mokpo National University, Jeonnam 534-729 (Korea, Republic of); Ham, Kyung-Sik [Department of Food Engineering, Mokpo National University, Jeonnam 534-729 (Korea, Republic of); Han, Song-Hee [Division of Maritime Transportation System, Mokpo National Maritime University, Jeonnam 530-729 (Korea, Republic of); Yoo, Jonghyun, E-mail: jyoo@appliedspectra.com [Applied Spectra, Inc., 46665 Fremont Boulevard, Fremont, CA 94538 (United States); Jeong, Sungho [School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

    2014-11-01

    We have investigated the discriminating power of the elements in edible sea salts using Laser-Induced Breakdown Spectroscopy (LIBS). For the ten different sea salts from South Korea, China, Japan, France, Mexico and New Zealand, LIBS spectra were recorded in the spectral range between 190 and 1040 nm, identifying the presence of Na, Cl, K, Ca, Mg, Li, Sr, Al, Si, Ti, Fe, C, O, N, and H. Intensity correlation analysis of the observed emission lines provided a valuable insight into the discriminating power of the different elements in the sea salts. The correlation analysis suggests that the elements with independent discrimination power can be categorized into three groups; those that represent dissolved ions in seawater (K, Li, and Mg), those that are associated with calcified particles (Ca and Sr), and those that are present in soils contained in the sea salts (Al, Si, Ti, and Fe). Classification models using a few emission lines selected based on the results from intensity correlation analysis and full broadband LIBS spectra were developed based on Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA) and their performances were compared. Our results indicate that effective combination of a few emission lines can provide a dependable model for discriminating the edible sea salts and the performance is not much degraded from that based on the full broadband spectra. This can be rationalized by the intensity correlation results. - Highlights: • Broadband LIBS spectra of various edible sea salts were obtained. • Intensity correlation of emission lines of the elements in edible sea salts was analyzed. • The elements were categorized into three groups with independent discriminating power. • The effective combination of a few lines can provide dependable classification models.

  13. Revealing discriminating power of the elements in edible sea salts: Line-intensity correlation analysis from laser-induced plasma emission spectra

    Science.gov (United States)

    Lee, Yonghoon; Ham, Kyung-Sik; Han, Song-Hee; Yoo, Jonghyun; Jeong, Sungho

    2014-11-01

    We have investigated the discriminating power of the elements in edible sea salts using Laser-Induced Breakdown Spectroscopy (LIBS). For the ten different sea salts from South Korea, China, Japan, France, Mexico and New Zealand, LIBS spectra were recorded in the spectral range between 190 and 1040 nm, identifying the presence of Na, Cl, K, Ca, Mg, Li, Sr, Al, Si, Ti, Fe, C, O, N, and H. Intensity correlation analysis of the observed emission lines provided a valuable insight into the discriminating power of the different elements in the sea salts. The correlation analysis suggests that the elements with independent discrimination power can be categorized into three groups; those that represent dissolved ions in seawater (K, Li, and Mg), those that are associated with calcified particles (Ca and Sr), and those that are present in soils contained in the sea salts (Al, Si, Ti, and Fe). Classification models using a few emission lines selected based on the results from intensity correlation analysis and full broadband LIBS spectra were developed based on Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA) and their performances were compared. Our results indicate that effective combination of a few emission lines can provide a dependable model for discriminating the edible sea salts and the performance is not much degraded from that based on the full broadband spectra. This can be rationalized by the intensity correlation results.

  14. Correcting for variable laser-target distances of laser-induced breakdown spectroscopy measurements with ChemCam using emission lines of Martian dust spectra

    Energy Technology Data Exchange (ETDEWEB)

    Melikechi, N.; Mezzacappa, A. [Optical Science Center for Applied Research, Delaware State University, Dover, DE (United States); Cousin, A.; Lanza, N.L. [Los Alamos National Laboratory, Los Alamos, NM (United States); Lasue, J. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Clegg, S.M. [Los Alamos National Laboratory, Los Alamos, NM (United States); Berger, G. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Wiens, R.C. [Los Alamos National Laboratory, Los Alamos, NM (United States); Maurice, S. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Tokar, R.L.; Bender, S. [Planetary Science Institute, Flagstaff, AZ (United States); Forni, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Breves, E.A.; Dyar, M.D. [Dept. of Astronomy, Mount Holyoke College, South Hadley, MA (United States); Frydenvang, J. [The Niels Bohr Institute, University of Copenhagen, Copenhagen (Denmark); Delapp, D. [Los Alamos National Laboratory, Los Alamos, NM (United States); Gasnault, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Newsom, H.; Ollila, A.M. [Earth and Planetary Sciences, University of New Mexico, Alburquerque, NM (United States); Lewin, E. [Institut des Sciences de la Terre, Universite Grenoble l-CNRS, Grenoble (France); and others

    2014-06-01

    As part of the Mars Science Laboratory, the ChemCam instrument acquires remote laser induced breakdown spectra at distances that vary between 1.56 m and 7 m. This variation in distance affects the intensities of the measured LIBS emission lines in non-trivial ways. To determine the behavior of a LIBS emission line with distance, it is necessary to separate the effects of many parameters such as laser energy, laser spot size, target homogeneity, and optical collection efficiency. These parameters may be controlled in a laboratory on Earth but for field applications or in space this is a challenge. In this paper, we show that carefully selected ChemCam LIBS emission lines acquired from the Martian dust can be used to build an internal proxy spectroscopic standard. This in turn, allows for a direct measurement of the effects of the distance of various LIBS emission lines and hence can be used to correct ChemCam LIBS spectra for distance variations. When tested on pre-launch LIBS calibration data acquired under Martian-like conditions and with controlled and well-calibrated targets, this approach yields much improved agreement between targets observed at various distances. This work lays the foundation for future implementation of automated routines to correct ChemCam spectra for differences caused by variable distance. - Highlights: • Selected Martian dust emission lines are used to correct for variable laser-target distances. • The correction model yields improved agreement between targets observed at various distances. • The impact of the model reduces the bias between predicted and actual compositions by as much as 70%. • When implemented, the model will yield spectral corrections for various ChemCam measurements. • This work is a foundation to perform novel stand-off LIBS measurements on Earth and other planets.

  15. Impact of temperature field inhomogeneities on the retrieval of atmospheric species from MIPAS IR limb emission spectra

    Directory of Open Access Journals (Sweden)

    M. Kiefer

    2010-04-01

    Full Text Available We examine volume mixing ratios (vmr retrieved from limb emission spectra recorded with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS. In level 2 (L2 data products of three different retrieval processors, which perform one dimensional (1-D retrievals, we find significant differences between species' profiles from ascending and descending orbit parts. The relative differences vary systematically with time of the year, latitude, and altitude. In the lower stratosphere their monthly means can reach maxima of 20% for CFC-11, CFC-12, HNO3, H2O, 10% for CH4 and N2O. Relative differences between monthly means of 1-D retrieval results and of the true atmospheric state can be expected to reach half of these percentage values, while relative differences in single vmr profiles might well exceed those numbers. Often there are no physical or chemical reasons for these differences, so they are an indicator for a problem in the data processing. The differences are generally largest at locations where the meridional temperature gradient of the atmosphere is strong. On the contrary, when performing the retrieval with a tomographic two dimensional (2-D retrieval, L2 products generally do not show these differences. This implies that inhomogeneities in the temperature field, and possibly in the species' fields, which are accounted for in the 2-D algorithm and not in standard 1-D processors, may cause significant deviations in the results. Inclusion of an externally given adequate temperature gradient in the forward model of a 1-D processor helps to reduce the observed differences. However, only the full tomographic approach is suitable to resolve the horizontal inhomogeneities. Implications for the use of the 1-D data, e.g. for validation, are discussed. The dependence of the ascending/descending differences on the observation strategy suggests that this problem is to be expected to affect in

  16. Computer-aided screening system for cervical precancerous cells based on field emission scanning electron microscopy and energy dispersive x-ray images and spectra

    Science.gov (United States)

    Jusman, Yessi; Ng, Siew-Cheok; Hasikin, Khairunnisa; Kurnia, Rahmadi; Osman, Noor Azuan Bin Abu; Teoh, Kean Hooi

    2016-10-01

    The capability of field emission scanning electron microscopy and energy dispersive x-ray spectroscopy (FE-SEM/EDX) to scan material structures at the microlevel and characterize the material with its elemental properties has inspired this research, which has developed an FE-SEM/EDX-based cervical cancer screening system. The developed computer-aided screening system consisted of two parts, which were the automatic features of extraction and classification. For the automatic features extraction algorithm, the image and spectra of cervical cells features extraction algorithm for extracting the discriminant features of FE-SEM/EDX data was introduced. The system automatically extracted two types of features based on FE-SEM/EDX images and FE-SEM/EDX spectra. Textural features were extracted from the FE-SEM/EDX image using a gray level co-occurrence matrix technique, while the FE-SEM/EDX spectra features were calculated based on peak heights and corrected area under the peaks using an algorithm. A discriminant analysis technique was employed to predict the cervical precancerous stage into three classes: normal, low-grade intraepithelial squamous lesion (LSIL), and high-grade intraepithelial squamous lesion (HSIL). The capability of the developed screening system was tested using 700 FE-SEM/EDX spectra (300 normal, 200 LSIL, and 200 HSIL cases). The accuracy, sensitivity, and specificity performances were 98.2%, 99.0%, and 98.0%, respectively.

  17. An iterative method in a probabilistic approach to the spectral inverse problem: Differential emission measure from line spectra and broadband data

    CERN Document Server

    Goryaev, F F; Urnov, A M; Oparin, S N; Hochedez, J -F; Reale, F; 10.1051/0004-6361/201014280

    2010-01-01

    Inverse problems are of great importance in astrophysics for deriving information about the physical characteristics of hot optically thin plasma sources from their EUV and X-ray spectra. We describe and test an iterative method developed within the framework of a probabilistic approach to the spectral inverse problem for determining the thermal structures of the emitting plasma. We also demonstrate applications of this method to both high resolution line spectra and broadband imaging data. Our so-called Bayesian iterative method (BIM) is an iterative procedure based on Bayes' theorem and is used to reconstruct differential emission measure (DEM) distributions. To demonstrate the abilities of the BIM, we performed various numerical tests and model simulations establishing its robustness and usefulness. We then applied the BIM to observable data for several active regions (AR) previously analyzed with other DEM diagnostic techniques: both SUMER/SOHO (Landi and Feldman, 2008) and SPIRIT/CORONAS-F (Shestov et al...

  18. On the origin of the absorption and emission line components in the spectra of PHL 293B

    CERN Document Server

    Tenorio-Tagle, Guillermo; Martinez-Gonzalez, Sergio; Terlevich, Roberto; Terlevich, Elena

    2015-01-01

    From the structure of PHL 293B and the physical properties of its ionizing cluster and based on results of hydrodynamic models, we point at the various events required to explain in detail the emission and absorption components seen in its optical spectrum. We ascribe the narrow and well centered emission lines, showing the low metallicity of the galaxy, to an HII region that spans through the main body of the galaxy. The broad emission line components are due to two off-centered supernova remnants evolving within the ionizing cluster volume and the absorption line profiles are due to a stationary cluster wind able to recombine at a close distance from the cluster surface, as originally suggested by Silich et al. (2004). Our numerical models and analytical estimates confirm the ionized and neutral column density values and the inferred X-ray emission derived from the observations.

  19. Ejecta patterns of Meteor Crater, Arizona derived from the linear un-mixing of TIMS data and laboratory thermal emission spectra

    Science.gov (United States)

    Ramsey, Michael S.; Christensen, Philip R.

    1992-01-01

    Accurate interpretation of thermal infrared data depends upon the understanding and removal of complicating effects. These effects may include physical mixing of various mineralogies and particle sizes, atmospheric absorption and emission, surficial coatings, geometry effects, and differential surface temperatures. The focus is the examination of the linear spectral mixing of individual mineral or endmember spectra. Linear addition of spectra, for particles larger than the wavelength, allows for a straight-forward method of deconvolving the observed spectra, predicting a volume percent of each endmember. The 'forward analysis' of linear mixing (comparing the spectra of physical mixtures to numerical mixtures) has received much attention. The reverse approach of un-mixing thermal emission spectra was examined with remotely sensed data, but no laboratory verification exists. Understanding of the effects of spectral mixing on high resolution laboratory spectra allows for the extrapolation to lower resolution, and often more complicated, remotely gathered data. Thermal Infrared Multispectral Scanner (TIMS) data for Meteor Crater, Arizona were acquired in Sep. 1987. The spectral un-mixing of these data gives a unique test of the laboratory results. Meteor Crater (1.2 km in diameter and 180 m deep) is located in north-central Arizona, west of Canyon Diablo. The arid environment, paucity of vegetation, and low relief make the region ideal for remote data acquisition. Within the horizontal sedimentary sequence that forms the upper Colorado Plateau, the oldest unit sampled by the impact crater was the Permian Coconino Sandstone. A thin bed of the Toroweap Formation, also of Permian age, conformably overlays the Coconino. Above the Toroweap lies the Permian Kiabab Limestone which, in turn, is covered by a thin veneer of the Moenkopi Formation. The Moenkopi is Triassic in age and has two distinct sub-units in the vicinity of the crater. The lower Wupatki member is a fine

  20. The Equilibrium and Pre-equilibrium Triton Emission Spectra of Some Target Nuclei for ( n, xt) Reactions up to 45 MeV Energy

    Science.gov (United States)

    Tel, E.; Kaplan, A.; Aydın, A.; Özkorucuklu, S.; Büyükuslu, H.; Yıldırım, G.

    2010-08-01

    Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So, working out the systematics of ( n,t) reaction cross sections and triton emission differential data are important for the given reaction taking place on various nuclei at different energies. In this study, ( n,xt) reactions for some target nuclei as 16O, 27Al, 59Co and 209Bi have been investigated up to 45 MeV incident neutron energy. In the calculations of the triton emission spectra, the pre-equilibrium and equilibrium effects have been used. The calculated results have been compared with the experimental data taken from the literature.

  1. The influence of visible light and inorganic pigments on fluorescence excitation emission spectra of egg-, casein- and collagen-based painting media

    Science.gov (United States)

    Nevin, A.; Anglos, D.; Cather, S.; Burnstock, A.

    2008-07-01

    Spectrofluorimetric analysis of proteinaceous binding media is particularly promising because proteins employed in paintings are often fluorescent and media from different sources have significantly different fluorescence spectral profiles. Protein-based binding media derived from eggs, milk and animal tissue have been used for painting and for conservation, but their analysis using non-destructive techniques is complicated by interferences with pigments, their degradation and their low concentration. Changes in the fluorescence excitation emission spectra of films of binding media following artificial ageing to an equivalent of 50 and 100 years of museum lighting include the reduction of bands ascribed to tyrosine, tryptophan and Maillard reaction products and an increase in fluorescent photodegradation. Fluorescence of naturally aged paint is dependent on the nature of the pigment present and, with egg-based media, in comparison with un-pigmented films, emissions ascribed to amino acids are more pronounced.

  2. Unravelling thermal emissivity spectra of the main minerals on Mercury's surface by comparison with ab initio calculated IR-HT vibrational frequencies

    Science.gov (United States)

    Stangarone, C.; Helbert, J.; Tribaudino, M.; Maturilli, A.; D'Amore, M.; Ferrari, S.; Prencipe, M.

    2015-12-01

    Spectral signatures of minerals are intimately related to the crystal structure; therefore they may represent a remote sensing model to determine surface composition of planetary bodies, by analysing their spectral reflectance and emission. However, one of the most critical point is data interpretation considering planetary surfaces, as Mercury, where the changes in spectral characteristics are induced by the high temperatures conditions (Helbert et al., 2013). The aim of this work is to interpret the experimental thermal emissivity spectra with an innovative approach: simulating IR spectra of the main mineral families that compose the surface of Mercury, focusing on pyroxenes (Sprague et al., 2002), both at room and high temperature, exploiting the accuracy of ab initio quantum mechanical calculations, by means of CRYSTAL14 code (Dovesi et al., 2014). The simulations will be compared with experimental emissivity measurements of planetary analogue samples at temperature up to 1000K, performed at Planetary Emissivity Laboratory (PEL) by Institute of Planetary Research (DLR, Berlin). Results will be useful to create a theoretical background to interpret HT-IR emissivity spectra that will be collected by the Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS), a spectrometer developed by DLR that will be on board of the ESA BepiColombo Mercury Planetary Orbiter (MPO) scheduled for 2017. The goal is to point out the most interesting spectral features for a geological mapping of Mercury and other rocky bodies, simulating the environmental conditions of the inner planets of Solar System. Dovesi R., Saunders V. R., Roetti C., Orlando R., Zicovich-Wilson C. M., Pascale F., Civalleri B., Doll K., Harrison N. M., Bush I. J., D'Arco P., Llunell M., Causà M. & Noël Y. 2014. CRYSTAL14 User's Manual, University of Torino. Sprague, A. L., Emery, J. P., Donaldson, K. L., Russell, R. W., Lynch, D. K., & Mazuk, A. L. (2002). Mercury: Mid-infrared (3-13.5

  3. Emissions and ambient distributions of Biogenic Volatile Organic Compounds (BVOC in a ponderosa pine ecosystem: interpretation of PTR-MS mass spectra

    Directory of Open Access Journals (Sweden)

    S. Kim

    2010-02-01

    Full Text Available Two proton-transfer-reaction mass spectrometry systems were deployed at the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen-Southern Rocky Mountain 2008 field campaign (BEACHON-SRM08; July to September, 2008 at the Manitou Forest Observatory in a ponderosa pine woodland near Woodland Park, Colorado USA. The two PTR-MS systems simultaneously measured BVOC emissions and ambient distributions of their oxidation products. Here, we present mass spectral analysis in a wide range of masses (m/z 40+ to 210+ to assess our understanding of BVOC emissions and their photochemical processing inside of the forest canopy. The biogenic terpenoids, 2-methyl-3-butene-2-ol (MBO, 50.2% and several monoterpenes (MT, 33.5% were identified as the dominant BVOC emissions from a transmission corrected mass spectrum (PTR-MS, averaged over the daytime (11 a.m. to 3 p.m., local time of three days. To assess contributions of oxidation products of local BVOC, we calculate an oxidation product spectrum with the OH- and ozone-initiated oxidation product distribution mass spectra of two major BVOC emissions at the ecosystem (MBO and β-pinene that were observed from laboratory oxidation experiments. The majority (~76% of the total signal in the transmission corrected PTR-MS spectra could be explained by identified compounds. The remainder are attributed to oxidation products of BVOC emitted from nearby ecosystems and transported to the site, and oxidation products of unidentified BVOC emitted from the ponderosa pine ecosystem.

  4. Lines and continuum sky emission in the near infrared: observational constraints from deep high spectral resolution spectra with GIANO-TNG

    CERN Document Server

    Oliva, E; Scuderi, S; Benatti, S; Carleo, I; Lapenna, E; Mucciarelli, A; Baffa, C; Biliotti, V; Carbonaro, L; Falcini, G; Giani, E; Iuzzolino, M; Massi, F; Sanna, N; Sozzi, M; Tozzi, A; Ghedina, A; Ghinassi, F; Lodi, M; Harutyunyan, A; Pedani, M

    2015-01-01

    Aims Determining the intensity of lines and continuum airglow emission in the H-band is important for the design of faint-object infrared spectrographs. Existing spectra at low/medium resolution cannot disentangle the true sky-continuum from instrumental effects (e.g. diffuse light in the wings of strong lines). We aim to obtain, for the first time, a high resolution infrared spectrum deep enough to set significant constraints on the continuum emission between the lines in the H-band. Methods During the second commissioning run of the GIANO high-resolution infrared spectrograph at La Palma Observatory, we pointed the instrument directly to the sky and obtained a deep spectrum that extends from 0.97 to 2.4 micron. Results The spectrum shows about 1500 emission lines, a factor of two more than in previous works. Of these, 80% are identified as OH transitions; half of these are from highly excited molecules (hot-OH component) that are not included in the OH airglow emission models normally used for astronomical ...

  5. Detailed analysis of hollow ions spectra from dense matter pumped by X-ray emission of relativistic laser plasma

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, S. B., E-mail: sbhanse@sandia.gov, E-mail: anatolyf@hotmail.com [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States); Colgan, J.; Abdallah, J. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Faenov, A. Ya., E-mail: sbhanse@sandia.gov, E-mail: anatolyf@hotmail.com [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Quantum Beam Science Directorate, Japan Atomic Energy Agency, Kyoto 619-0215 (Japan); Pikuz, S. A.; Skobelev, I. Yu. [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Wagenaars, E.; Culfa, O.; Dance, R. J.; Tallents, G. J.; Rossall, A. K.; Woolsey, N. C. [York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom); Booth, N.; Lancaster, K. L. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX (United Kingdom); Evans, R. G. [Department of Physics, Imperial College, London SW7 2AZ (United Kingdom); Gray, R. J.; McKenna, P. [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 ONG (United Kingdom); Kaempfer, T.; Schulze, K. S. [Helmholtzinstitut Jena, Jena D-07743 (Germany); Uschmann, I. [Helmholtzinstitut Jena, Jena D-07743 (Germany); Institut für Optik und Quantenelektronic, Friedrich-Schiller-Universität Jena, Max-Wien Platz 1, Jena, D-07743 (Germany); and others

    2014-03-15

    X-ray emission from hollow ions offers new diagnostic opportunities for dense, strongly coupled plasma. We present extended modeling of the x-ray emission spectrum reported by Colgan et al. [Phys. Rev. Lett. 110, 125001 (2013)] based on two collisional-radiative codes: the hybrid-structure Spectroscopic Collisional-Radiative Atomic Model (SCRAM) and the mixed-unresolved transition arrays (MUTA) ATOMIC model. We show that both accuracy and completeness in the modeled energy level structure are critical for reliable diagnostics, investigate how emission changes with different treatments of ionization potential depression, and discuss two approaches to handling the extensive structure required for hollow-ion models with many multiply excited configurations.

  6. The application and comparison of several chemometric methods of excitation-emission matrix spectra in studying the interactions of metal complexes with DNA.

    Science.gov (United States)

    Zhang, Fang; Zhang, Qian-Qian; Wang, Wei-Guo; Zhu, Chen-Jian; Wang, Xiu-Lin

    2007-09-19

    The interactions of fs DNA and two metal complexes [Cu(phen)SO4] x 2 H2O and [Ni(phen)SO4] x 2 H2O were explored by several chemometric methods, including parallel factor (PARAFAC), singular value decomposition-least squares (SVD-LS), and singular value decomposition-nonnegative least squares (SVD-NNLS) of excitation-emission matrix spectra (EEMs). The applications of SVD-LS and SVD-NNLS in this domain have been discussed. Rayleigh scatter part is avoided by ordered zero and reconstructed by linear interpolation. The importance of avoiding Rayleigh scatter has also been discussed. All the three methods do well in qualitative analysis. SVD-LS does best in present small changes of ethidium bromide (EB). In order to get accurate results, PARAFAC and SVD-NNLS can be utilized together in quantitative analysis. All the three chemometric methods indicate that the DNA binding modes of [Cu(phen)SO4] x 2 H2O are hydrogen bond effect and intercalation, while intercalation is the only DNA binding mode for [Ni(phen)SO4] x 2 H2O. These results are verified by the electronic absorption and emission fluorescence spectra. Just like PARAFAC, both SVD-LS and SVD-NNLS are proven to be convenient and convincing in studying the interactions between nucleic acids and complexes.

  7. Solvatochromic effect in absorption and emission spectra of star-shaped bipolar derivatives of 1,3,5-triazine and carbazole. A time-dependent density functional study.

    Science.gov (United States)

    Baryshnikov, Gleb V; Bondarchuk, Sergey V; Minaeva, Valentina A; Ågren, Hans; Minaev, Boris F

    2017-02-01

    A series of three star-shaped compounds containing both donor (carbazole) and acceptor (2,4,6-triphenyl-1,3,5-triazine) moieties linked through various linking bridges was studied theoretically at the linear response TD-DFT level of theory to describe their absorption and fluorescence spectra. The concept of a localized charge-transfer excited state has been applied successfully to explain the observed strong solvatochromic effect in the emission spectra of the studied molecules, which can be utilized for the fabrication of color tunable solution-processable OLEDs. The concept is in particularly applicable to donor-acceptor species with a C 3 symmetry point group where the static dipole moment changes dramatically upon electronic excitation. An important peculiarity of the studied molecules is that they are characterized by non-zero values of the HOMO and LUMO orbitals in the same common part of molecular space that provides a large electric dipole transition moment for both light absorption and emission. Graphical abstract Star-shaped C 3 symmetry point group derivatives for color tunable OLEDs.

  8. Prediction of the hydrophilic antioxidant capacity of tomato pastes from the IR and fluorescence excitation-emission spectra of extracts and intact samples.

    Science.gov (United States)

    Orzel, Joanna; Stanimirova, Ivana; Czarnik-Matusewicz, Boguslawa; Daszykowski, Michal

    2015-06-01

    The performance of the recently proposed excitation-emission fluorescence method was compared to the method using infrared measurements for the evaluation of the antioxidant properties of intact samples and extracts that had been obtained from tomato pastes. The oxygen radical absorbance capacity assay (ORAC) was applied in order to estimate the antioxidant capacity of the extracts, while the Folin-Ciocalteu reagent was adopted for the evaluation of the total phenolic content. The optimal extraction conditions for tomato pastes (three minutes of sonication under 80°C) were determined using the central composite design. Chemometric models such as the partial least squares regression and its N-way variant were further constructed in order to predict the antioxidant capacity or total phenolic content of the samples using either the IR or fluorescence spectra. The prediction errors that were obtained for the total antioxidant content were evaluated as the Trolox equivalents from the ORAC assay and were found to be equal to 2.011 (14.21%) for the fluorescence and 2.426 (17.15%) for the IR spectra, respectively. The prediction errors of the total phenolic content expressed as gallic acid equivalents were 0.067 (10.78%) for the fluorescence and 0.033 (5.36%) for the IR spectra, which were used as independent variables in the regression models.

  9. The 3D-HST Survey: Hubble Space Telescope WFC3/G141 grism spectra, redshifts, and emission line measurements for $\\sim 100,000$ galaxies

    CERN Document Server

    Momcheva, Ivelina G; van Dokkum, Pieter G; Skelton, Rosalind E; Whitaker, Katherine E; Nelson, Erica J; Fumagalli, Mattia; Maseda, Michael V; Leja, Joel; Franx, Marijn; Rix, Hans-Walter; Bezanson, Rachel; Da Cunha, Elisabete; Dickey, Claire; Schreiber, Natascha M Förster; Illingworth, Garth; Kriek, Mariska; Labbé, Ivo; Lange, Johannes Ulf; Lundgren, Britt F; Magee, Daniel; Marchesini, Danilo; Oesch, Pascal; Pacifici, Camilla; Patel, Shannon G; Price, Sedona; Tal, Tomer; Wake, David A; van der Wel, Arjen; Wuyts, Stijn

    2015-01-01

    We present reduced data and data products from the 3D-HST survey, a 248-orbit HST Treasury program. The survey obtained WFC3 G141 grism spectroscopy in four of the five CANDELS fields: AEGIS, COSMOS, GOODS-S, and UDS, along with WFC3 $H_{140}$ imaging, parallel ACS G800L spectroscopy, and parallel $I_{814}$ imaging. In a previous paper (Skelton et al. 2014) we presented photometric catalogs in these four fields and in GOODS-N, the fifth CANDELS field. Here we describe and present the WFC3 G141 spectroscopic data, again augmented with data from GO-1600 in GOODS-N. The data analysis is complicated by the fact that no slits are used: all objects in the WFC3 field are dispersed, and many spectra overlap. We developed software to automatically and optimally extract interlaced 2D and 1D spectra for all objects in the Skelton et al. (2014) photometric catalogs. The 2D spectra and the multi-band photometry were fit simultaneously to determine redshifts and emission line strengths, taking the morphology of the galaxie...

  10. Gamma-Ray Emission Spectra as a Constraint on Calculations of 234,236,238U Neutron-Capture Cross Sections

    Energy Technology Data Exchange (ETDEWEB)

    Ullmann, John Leonard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kawano, Toshihiko [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bredeweg, Todd Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Baramsai, Bayarbadrakh [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Couture, Aaron Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Haight, Robert Cameron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jandel, Marian [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mosby, Shea Morgan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); O' Donnell, John M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vieira, David J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wilhelmy, Jerry B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Becker, John A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wu, Ching-Yen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Krticka, Milan [Charles Univ., Prague (Czech Republic)

    2015-05-28

    Neutron capture cross sections in the “continuum” region (>≈1 keV) and gamma-emission spectra are of importance to basic science and many applied fields. Careful measurements have been made on most common stable nuclides, but physicists must rely on calculations (or “surrogate” reactions) for rare or unstable nuclides. Calculations must be benchmarked against measurements (cross sections, gamma-ray spectra, and <Γγ>). Gamma-ray spectrum measurements from resolved resonances were made with 1 - 2 mg/cm2 thick targets; cross sections at >1 keV were measured using thicker targets. The results show that the shape of capture cross section vs neutron energy is not sensitive to the form of the strength function (although the magnitude is); the generalized Lorentzian E1 strength function is not sufficient to describe the shape of observed gamma-ray spectra; MGLO + “Oslo M1” parameters produces quantitative agreement with the measured 238U(n,γ) cross section; additional strength at low energies (~ 3 MeV) -- likely M1-- is required; and careful study of complementary results on low-lying giant resonance strength is needed to consistently describe observations.

  11. 自动识别发射线恒星光谱的新方法%A New Automated Method to Identify Emission Line Star from Massive Spectra

    Institute of Scientific and Technical Information of China (English)

    潘景昌; 张彩明; 韦鹏; 罗阿理; 赵永恒

    2012-01-01

    Stellar spectra are characterized by obvious absorption lines or absorption bands, while those with emission lines are usually special stars such as cataclysmic variable stars (CVs), HerbigAe/Be etc. The further study of this kind of spectra is meaningful. The present paper proposed a new method to identify emission line stars (ELS) spectra automatically. After the continuum normalization is done for the original spectral flux, line detection is made by comparing the normalized flux with the mean and standard deviation of the flux in its neighbor region. The results of the experiment on massive spectra from SDSS DR8 indicate that the method can identify ELS spectra completely and accurately. Since no complex transformation and computation are involved in this method, the identifying process is fast and it is ideal for the ELS detection in large sky survey projects like LAMOST and SDSS.%恒星光谱一般具有明显的吸收线或者吸收带特征,而具有发射线的恒星光谱对应着特殊类型的恒星、如激变变星、Herbig Ae/Be等.对这些光谱的后续研究有着重要的意义.本文提出了一种能够自动识别发射线恒星光谱的方法.该方法首先对光谱进行连续谱归一化,然后通过比较谱线对应的流量及其邻域流量的均值和标准差,来判断是否存在发射线.对SDSS DR8大样本数据的实验表明,该方法能够完整、准确地识别发射线恒星.而且,由于该方法不涉及复杂的变换和运算,因而识别速度非常快,可用于诸如LAMOST和SDSS这样大型光谱巡天项目中发现发射线恒星光谱.

  12. PARAFAC modeling of fluorescence excitation - Emission spectra of fish bile for rapid en route screening of PAC exposure

    DEFF Research Database (Denmark)

    Christensen, Jan H.; Tomasi, Giorgio; Strand, Jakob

    2009-01-01

    with parallel factor analysis (PARAFAC) and may constitute an alternative to fixed wavelength fluorescence and synchronous fluorescence spectroscopy (M). PARAFAC was applied to excitation-emission matrices (EEMs) of bile samples of shorthorn sculpins and European eels collected in Greenland and Denmark...

  13. c2d Spitzer IRS spectra of embedded low-mass young stars : gas-phase emission lines

    NARCIS (Netherlands)

    Lahuis, F.; van Dishoeck, E. F.; Jorgensen, J. K.; Blake, G. A.; Evans, N. J.

    2010-01-01

    Context. A survey of mid-infrared gas-phase emission lines of H(2), H(2)O and various atoms toward a sample of 43 embedded low-mass young stars in nearby star-forming regions is presented. The sources are selected from the Spitzer "Cores to Disks" (c2d) legacy program. Aims. The environment of embed

  14. Ab initio calculation of X-ray emission and IR spectra of the hydrofullerene C 60H 36

    Science.gov (United States)

    Bulusheva, L. G.; Okotrub, A. V.; Antich, A. V.; Lobach, A. S.

    2001-05-01

    Two isomers of the hydrofullerene C 60H 36 with T and D3 d symmetry were calculated using ab initio Hartree-Fock self-consistent field (HF-SCF). The T symmetry isomer in which the benzenoid rings occupy tetrahedral positions is predicted to be lower in energy than the other considered isomer. Simulated CK α spectra of the isomers were compared with the X-ray fluorescence spectrum of the hydrofullerene C 60H 36 prepared by the transfer hydrogenation method. The short-wave maximum intensity of the CK α spectrum of C 60H 36 was shown to be sensitive to the number of π electrons in the high-occupied levels of the molecule. Although the theoretical spectra are similar in appearance, the T isomer seems to be in better accordance with the experiment. Furthermore, the computed infrared frequencies and intensities for this isomer were found to correlate well with features in the measured spectrum of C 60H 36. The most intense peak in the low-frequency spectral region was shown to correspond to the skeletal vibrations of the benzenoid rings.

  15. The ground-based H-, K-, and L-band absolute emission spectra of HD 209458b

    Energy Technology Data Exchange (ETDEWEB)

    Zellem, Robert T.; Griffith, Caitlin A. [Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721 (United States); Deroo, Pieter; Swain, Mark R. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Waldmann, Ingo P., E-mail: rzellem@lpl.arizona.edu [University College London, Department of Physics and Astronomy, Gower Street, London WC1E 6BT (United Kingdom)

    2014-11-20

    Here we explore the capabilities of NASA's 3.0 m Infrared Telescope Facility (IRTF) and SpeX spectrometer and the 5.08 m Hale telescope with the TripleSpec spectrometer with near-infrared H-, K-, and L-band measurements of HD 209458b's secondary eclipse. Our IRTF/SpeX data are the first absolute L-band spectroscopic emission measurements of any exoplanet other than the hot Jupiter HD 189733b. Previous measurements of HD 189733b's L band indicate bright emission hypothesized to result from non-LTE CH{sub 4} ν{sub 3} fluorescence. We do not detect a similar bright 3.3 μm feature to ∼3σ, suggesting that fluorescence does not need to be invoked to explain HD 209458b's L-band measurements. The validity of our observation and reduction techniques, which decrease the flux variance by up to 2.8 orders of magnitude, is reinforced by 1σ agreement with existent Hubble/NICMOS and Spitzer/IRAC1 observations that overlap the H, K, and L bands, suggesting that both IRTF/SpeX and Palomar/TripleSpec can measure an exoplanet's emission with high precision.

  16. Influence of COsub>2sub> pressure on the emission spectra and plasma parameters in underwater laser-induced breakdown spectroscopy.

    Science.gov (United States)

    Goueguel, Christian L; McIntyre, Dustin L; Jain, Jinesh C

    2016-12-01

    Optical emission spectroscopic studies have been carried out to investigate the pressure effect of COsub>2sub> on laser-produced underwater plasma. The plasma was generated by focusing 1064 nm, 6 ns pulses from a Nd:YAG laser in a COsub>2sub>-bearing solution. The temporal evolution of the continuum emission, Sr and Ba lines, and plasma electron density and temperature was characterized under COsub>2sub> pressure ranging from 10 to 300 bars. The electron density measurements were made using the Stark broadening of the 455.40 nm Ba II line, while the temperature measurements have been performed by the Saha-Boltzmann method using the Sr I-II lines at 460.73 and 407.77 nm, respectively. It was found that COsub>2sub> pressure has little effect on the emission line intensity and signal-to-background ratio. The electron density and the temperature are found to be independent of the COsub>2sub> pressure at early times. When time becomes longer, the electron density exhibits an appreciable rise as the COsub>2sub> pressure increases, while the temperature is found to be unchanged.

  17. Theoretical modeling and analysis of the emission spectra of a ChemCam standard: Basalt BIR-1A

    Energy Technology Data Exchange (ETDEWEB)

    Colgan, J. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Judge, E.J. [Chemical Diagnostics and Engineering, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Johns, H.M.; Kilcrease, D.P. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Barefield, J.E. [Chemical Diagnostics and Engineering, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); McInroy, R. [Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hakel, P. [Computational Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Wiens, R.C. [Space and Remote Sensing Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Clegg, S.M. [Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2015-08-01

    We report on efforts to perform theoretical modeling of the emission spectrum measured from a basalt sample. We compare our calculations with measurements that were made to provide standards for the ChemCam instrument on the Mars Science Laboratory. We find that to obtain good agreement between modeling and the measurement, it is necessary to determine atomic and ionic level populations via a multi-element approach in which the free electron density that is created influences all the species within the plasma. Calculations that consider each element separately are found to be in poorer agreement with the measured spectrum, indicating that the ‘matrix effect’ term often used to describe the influence of other species on the emission spectrum from a given element is due to the influence of the global electron density of the plasma. We explore the emission features in both the visible and near-infrared wavelength ranges, and also examine radiation transport effects for some of the most intense features found in the basalt spectrum. Finally, we also provide comparisons of the ChemCam measurement with new high-resolution spectral measurements. - Highlights: • LIBS basalt spectrum • Ab-initio theoretical modeling • Discussion of matrix effects • Discussion of radiation transport effects • High-resolution measurements of Basalt.

  18. HST/COS Spectra of DF Tau and V4046 SGR: First Detection of Molecular Hydrogen Absorption Against the Ly$\\alpha$ Emission Line

    CERN Document Server

    Yang, Hao; France, Kevin

    2011-01-01

    We report the first detection of molecular hydrogen (H$_{2}$) absorption in the Lyman-$\\alpha$ emission line profiles of two classical T Tauri stars (CTTSs), DF Tau and V4046 Sgr, observed by \\emph{HST}/COS. This absorption is the energy source for many of the Lyman-band H$_{2}$ fluorescent lines commonly seen in the far-ultraviolet spectra of CTTSs. We find that the absorbed energy in the H$_{2}$ pumping transitions from a portion of the Lyman-$\\alpha$ line significantly differ from the amount of energy in the resulting fluorescent emission. By assuming additional absorption in the H I Lyman-$\\alpha$ profile along our light of sight, we can correct the H$_{2}$ absorption/emission ratios so that they are close to unity. The required H I absorption for DF Tau is at a velocity close to the radial velocity of the star, consistent with H I absorption in the edge-on disk and interstellar medium. For V4046 Sgr, a nearly face-on system, the required absorption is between +100 km/s and +290 km/s, most likely resultin...

  19. Emissions and ambient distributions of Biogenic Volatile Organic Compounds (BVOC in a Ponderosa pine ecosystem: interpretation of PTR-MS mass spectra

    Directory of Open Access Journals (Sweden)

    S. Kim

    2009-10-01

    Full Text Available Two proton-transfer-reaction mass spectrometry systems were deployed at the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen-Southern Rocky Mountain 2008 field campaign (BEACHON-SRM08; July to September 2008 at the Manitou Forest observatory in a Ponderosa pine woodland near Woodland Park, Colorado USA to simultaneously measure BVOC emissions and ambient distributions of their oxidation products. Here, we present mass spectral analysis in a wide range of masses (m/z=40+ to 210+ to assess our understanding of BVOC emissions and their photochemical process inside of the forest canopy. The biogenic terpenoids, 2-methyl-3-butene-2-ol (MBO, 50.2% and several monoterpenes (MT, 33.5% were identified as the dominant BVOC emissions from a transmission corrected mass spectrum, averaged over the daytime (11 am to 3 p.m., local time of three days. To assess contributions of oxidation products of local BVOC, we calculate a oxidation product spectrum with the OH- and ozone-initiated oxidation product distribution mass spectra of two major BVOC at the ecosystem (MBO and β-pinene that were observed from laboratory oxidation experiments. A majority (~73% of the total signal could be explained by known compounds. The remainder are attributed to oxidation products of BVOC, emitted from nearby ecosystems and transported to the site, and oxidation products of unidentified BVOC emitted from the Ponderosa pine ecosystem.

  20. X-ray spectra from magnetar candidates - III. Fitting SGRs/AXPs soft X-ray emission with non-relativistic Monte Carlo models

    CERN Document Server

    Zane, S; Turolla, R; Nobili, L

    2009-01-01

    Within the magnetar scenario, the "twisted magnetosphere" model appears very promising in explaining the persistent X-ray emission from the Soft Gamma Repeaters and the Anomalous X-ray Pulsars (SGRs and AXPs). In the first two papers of the series, we have presented a 3D Monte Carlo code for solving radiation transport as soft, thermal photons emitted by the star surface are resonantly upscattered by the magnetospheric particles. A spectral model archive has been generated and implemented in XSPEC. Here we report on the systematic application of our spectral model to different XMM-Newton and Integral observations of SGRs and AXPs. We find that the synthetic spectra provide a very good fit to the data for the nearly all the source (and source states) we have analyzed.

  1. K band SINFONI spectra of two $z \\sim 5$ SMGs: upper limits to the un-obscured star formation from [O II] optical emission line searches

    CERN Document Server

    Couto, Guilherme S; López, Javier Piqueras; Storchi-Bergmann, Thaisa; Arribas, Santiago

    2016-01-01

    We present deep SINFONI K band integral field spectra of two submillimeter (SMG) galaxy systems: BR 1202-0725 and J1000+0234, at $z=4.69$ and $4.55$ respectively. Spectra extracted for each object in the two systems do not show any signature of the [O II]$\\lambda\\lambda$3726,29\\AA$\\,$ emission-lines, placing upper flux limits of $3.9$ and $2.5 \\times 10^{-18}\\,$${\\rm erg\\,s^{-1}\\,\\,cm^{-2} \\,}$ for BR 1202-0725 and J1000+0234, respectively. Using the relation between the star formation rate (SFR) and the luminosity of the [O II] doublet from Kennicutt (1998), we estimate unobscured SFR upper limits of $\\sim$ $10-15\\,\\rm M_\\odot\\,yr^{-1} \\,$ and $\\sim$ $30-40\\,\\rm M_\\odot\\,yr^{-1} \\,$ for the objects of the two systems, respectively. For the SMGs, these values are at least two orders of magnitude lower than those derived from SED and IR luminosities. The differences on the SFR values would correspond to internal extinction of, at least, $3.4 - 4.9$ and $2.1 - 3.6$ mag in the visual for BR 1202-0725 and J1000+0...

  2. Temperature dependence of photoluminescence spectra for green light emission from InGaN/GaN multiple wells.

    Science.gov (United States)

    Liu, W; Zhao, D G; Jiang, D S; Chen, P; Liu, Z S; Zhu, J J; Shi, M; Zhao, D M; Li, X; Liu, J P; Zhang, S M; Wang, H; Yang, H; Zhang, Y T; Du, G T

    2015-06-15

    Three green light emitting InGaN/GaN multiple quantum well (MQW) structures with different In composition grown by metal-organic chemical vapor deposition are investigated by the X-ray diffraction and the temperature-dependent photoluminescence (PL) measurements. It is found that when the In composition increases in the InGaN/GaN MQWs, the PL spectral bandwidth may anomalously decrease with increasing temperature. The reduction of PL spectral bandwidth may be ascribed to the enhanced non-radiative recombination process which may lower the light emission efficiency of the localized luminescent centers with shallow localization energy in the high-In-content InGaN quantum wells and also cause a reduction of integrated PL intensity.

  3. Ultrafast Time-Resolved Emission and Absorption Spectra of meso-Pyridyl Porphyrins upon Soret Band Excitation Studied by Fluorescence Up-Conversion and Transient Absorption Spectroscopy.

    Science.gov (United States)

    Venkatesh, Yeduru; Venkatesan, M; Ramakrishna, B; Bangal, Prakriti Ranjan

    2016-09-08

    A comprehensive study of ultrafast molecular relaxation processes of isomeric meso-(pyridyl) porphyrins (TpyPs) has been carried out by using femtosecond time-resolved emission and absorption spectroscopic techniques upon pumping at 400 nm, Soret band (B band or S2), in 4:1 dichloromethane (DCM) and tetrahydrofuran (THF) solvent mixture. By combined studies of fluorescence up-conversion, time-correlated single photon counting, and transient absorption spectroscopic techniques, a complete model with different microscopic rate constants associated with elementary processes involved in electronic manifolds has been reported. Besides, a distinct coherent nuclear wave packet motion in Qy state is observed at low-frequency mode, ca. 26 cm(-1) region. Fluorescence up-conversion studies constitute ultrafast time-resolved emission spectra (TRES) over the whole emission range (430-710 nm) starting from S2 state to Qx state via Qy state. Careful analysis of time profiles of up-converted signals at different emission wavelengths helps to reveal detail molecular dynamics. The observed lifetimes are as indicated: A very fast decay component with 80 ± 20 fs observed at ∼435 nm is assigned to the lifetime of S2 (B) state, whereas being a rise component in the region of between 550 and 710 nm emission wavelength pertaining to Qy and Qx states, it is attributed to very fast internal conversion (IC) occurring from B → Qy and B → Qx as well. Two distinct components of Qy emission decay with ∼200-300 fs and ∼1-1.5 ps time constants are due to intramolecular vibrational redistribution (IVR) induced by solute-solvent inelastic collisions and vibrational redistribution induced by solute-solvent elastic collision, respectively. The weighted average of these two decay components is assigned as the characteristic lifetime of Qy, and it ranges between 0.3 and 0.5 ps. An additional ∼20 ± 2 ps rise component is observed in Qx emission, and it is assigned to the formation time of

  4. [Excitation-Emission Matrix Fluorescence Spectra Characteristics of DOM in Integrated Verical Flow Constructed Wetland for Treating Eutrophic Water].

    Science.gov (United States)

    Li, Shu-juan; Ge, Li-yun; Deng, Huan-huan

    2015-04-01

    Three-dimensional fluorescence parameters can reflect classification, properties and content change of pollutants in wastewater treatment. In the present paper, by using three-dimensional fluorescence characteristic analysis, comparative analysis of conventional organic pollutants such as COD, TN and TP, and three dimensional fluorescence spectrum analysis, the classification and content of dissolved organic pollutants were identified. We studied fluorescence spectra, fluorescence peak (R. U.), fluorescence index (FI), humification index (HIX) of DOM's four components in the entrance and effluent water and interstitial water, as well as the correlation between these four components and COD, TN and TP. The results showed that the position and intensity of the characteristic fluorescence peak center changed significantly before and after sewage treatment, indicating that the relative composition and content of the organic wastewater varied with wastewater treatment. Furthermore, the test results presented that humic-like composition was not degraded significantly, while protein-like composition was degraded significantly. And the protein-like component and COD, TN and TP presented significant positive correlation. This paper analyzed the fluorescence characteristics changes of dissolved organic matter in sewage treatment by using three-dimensional fluorescence spectrometry, and discussed the feasibility of three-dimensional fluorescence technique applied for description of dissolved organic pollutant degradation rule in the wastewater treatment process.

  5. Environmentally friendly Zn0.75Cd0.25S/PVA heterosystem nanocomposite: UV-stimulated emission and absorption spectra

    Science.gov (United States)

    Imam, N. G.; Mohamed, Mohamed Bakr

    2016-02-01

    Zn0.75Cd0.25S nanoparticles prepared at different temperatures were composited with polyvinyl alcohol for functionalization it in wide spectrum of applications such as in photocatalysis. The nanostructure of the Zn0.75Cd0.25S mother phase is confirmed by X-ray diffraction in addition to absorption and fluorescence spectra. UV/VIS. measurements show that, the transmittance coefficient of Zn0.75Cd0.25S/PVA nanocomposite is lesser than that of pure PVA by 0.33% and varies upon increasing the preparation temperature; reaching a maximum value for the sample prepared at 300 °C. It was found that the optical band gap tunes with annealing temperature which, in turns, with particle size. The refractive index of the Zn0.75Cd0.25S/PVA nanocomposite films decrease with increasing wavelength and saturates at high wavelengths. The optical conductivity increases with increasing photon energy which may be due to the excitation of electrons by photon energy. The optical conductivity of Zn0.75Cd0.25S/PVA nanocomposite is lesser than that of pure PVA and it decreases as the preparation temperature of Zn0.75Cd0.25S nanoparticles in PVA matrix increases which could be related to the decrease in the extinction coefficient and the density of localized states in the gap. Abroad peak deconvoluted, by Gaussian fitting function, into two violet and blue colors was observed in the fluorescence spectra under UV light irradiation. The two emission bands are attributed to band edge emission and neutral oxygen vacancies respectively. Analysis of fluorescence (FL) spectra reveals quenching in FL intensity and a peak shifting towards the lower wavelength side with increasing the preparation temperature of the mother phase. The results suggest that the 200 °C Zn0.75Cd0.25S/PVA nanocomposites have been regarded as a promising candidate in many technical fields, such as photocatalytic hydrogen production and/or photocatalytic degradation of organic dyes under UV irradiation due to its high optical

  6. Synthesis of ZnO quantum dots and their agglomeration mechanisms along with emission spectra based on ageing time and temperature

    Science.gov (United States)

    Qiao, Bo; Zhao, Suling; Xu, Zheng; Xu, Xurong

    2016-09-01

    The ZnO quantum dots (QDs) were synthesized with improved chemical solution method. The size of the ZnO QDs is exceedingly uniform with a diameter of approximately 4.8 nm, which are homogeneously dispersed in ethanol. The optical absorption edge shifts from 370 nm of bulk material to 359 nm of QD materials due to the quantum size effect, while the photoluminescence peak shifts from 375 nm to 387 nm with the increase of the density of ZnO QDs. The stability of ZnO QDs was studied with different dispersion degrees at 0 °C and at room temperature of 25 °C. The agglomeration mechanisms and their relationship with the emission spectra were uncovered for the first time. With the ageing of ZnO QDs, the agglomeration is aggravated and the surface defects increase, which leads to the defect emission. Project supported by the FRFCU (Grant No. 2016JBM066), 863 Program (Grant No. 2013AA032205), the National Natural Science Foundation of China (Grant Nos. 61575019, 51272022, and 11474018), and RFDP (Grant Nos. 20120009130005 and 20130009130001).

  7. Three green luminescent cadmium complexes containing 8-aminoquinoline ligands: Syntheses, crystal structures, emission spectra and DFT calculations

    Energy Technology Data Exchange (ETDEWEB)

    Xu Heng; Huang Liangfang; Guo Limin; Zhang Yuanguang [Anhui Key Laboratory for Functional Coordination Compounds, Anqing Normal College, Anqing 246011 (China); Ren Xiaoming [Anhui Key Laboratory for Functional Coordination Compounds, Anqing Normal College, Anqing 246011 (China); Department of Applied Chemistry, Science College, Nanjing University of Technology, 5 Xin Mo Fan Road, Nanjing 210009 (China)], E-mail: xmren@njut.edu.cn; Song You [Coordination Chemistry Institute and State Key Laboratory, Nanjing University, Nanjing 210093 (China); Xie Jingli [School of Chemistry and Bio21 Institute, The University of Melbourne, Parkville, VIC 3010 (Australia)

    2008-10-15

    Three complexes, Cd(8-aminoql){sub 2}x{sub 2} (8-aminoql=8-aminoquinoline; X{sup -}=ClO{sub 4}{sup -}, SCN{sup -}, 1 and 2, respectively) and Cd(8-aminoql)(N{sub 3}){sub 2} (3), were synthesized and structurally characterized. For each complex, the Cd{sup 2+} ion exhibits distorted octahedral coordination geometry. Two 8-aminoquinoline molecules and two counter-anions are coordinated to the Cd{sup 2+} center to form a mononuclear species with two trans-ClO{sub 4}{sup -} anions for 1, while two SCN{sup -} anions adopt a cis-configuration for 2. The intermolecular H-bonding interactions between the -NH{sub 2} groups and the O atom (1) and the S atom (2) result in the formation of a 2-D layered structure. In the crystal of 3, the N{sub 3}{sup -} anions bridging the neighboring Cd(8-aminoql){sup 2+} units form a 1-D coordination polymer. The three complexes emit green luminescence. The emission bands possess a broad asymmetric feature, which can be assigned to L'LCT transitions based on DFT and TDDFT calculations.

  8. Simulation of emission molecular spectra by a semi-automatic programme package: the case of C2 and CN diatomic molecules emitting during laser ablation of a graphite target in nitrogen environment.

    Science.gov (United States)

    Acquaviva, S

    2004-07-01

    Some emission spectra of diatomic molecules were calculated by a semi-automatic programme package in order to infer the rotational and vibrational temperatures in Boltzmann distribution by comparing them with the corresponding experimental ones. The calculation procedure was applied in the case of CN radical and C2 molecule whose optical emission spectra were recorded during pulsed excimer laser ablation of a graphite target in low-pressure nitrogen environment. Computed similar or dissimilar values of rotational and vibrational temperatures let to verify the existence or not of local thermodynamic equilibrium and to hypothesise the temporal range necessary to establish it in such experiments.

  9. Estimation of Mass-Loss Rates from Emission Line Profiles in the UV Spectra of Cool Stars

    Science.gov (United States)

    Carpenter, K. G.; Robinson, R. D.; Harper, G. M.

    1999-01-01

    The photon-scattering winds of cool, low-gravity stars (K-M giants and supergiants) produce absorption features in the strong chromospheric emission lines. This provides us with an opportunity to assess important parameters of the wind, including flow and turbulent velocities, the optical depth of the wind above the region of photon creation, and the star's mass-loss rate. We have used the Lamers et al. Sobolev with Exact Integration (SEI) radiative transfer code along with simple models of the outer atmospheric structure to compute synthetic line profiles for comparison with the observed line profiles. The SEI code has the advantage of being computationally fast and allows a great number of possible wind models to be examined. We therefore use it here to obtain initial first-order estimates of the wind parameters. More sophisticated, but more time-consuming and resource intensive calculations will be performed at a later date, using the SEI-deduced wind parameters as a starting point. A comparison of the profiles over a range of wind velocity laws, turbulence values, and line opacities allows us to constrain the wind parameters, and to estimate the mass-loss rates. We have applied this analysis technique (using lines of Mg II, 0 I, and Fe II) so far to four stars: the normal K5-giant alpha Tau, the hybrid K-giant gamma Dra, the K5 supergiant lambda Vel, and the M-giant gamma Cru. We present in this paper a description of the technique, including the assumptions which go into its use, an assessment of its robustness, and the results of our analysis.

  10. Effect of [Li]/[Nb] ratios on the absorption and up-conversion emission spectra in In:Yb:Ho:LiNbO{sub 3} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Li, E-mail: daili198108@126.com [Applied Science College, Harbin University of Science and Technology, Harbin 150080 (China); State Key Laboratory of Crystal Material, Shandong University, Jinan 250100 (China); Yan, Zhehua; Jiao, Shanshan [Applied Science College, Harbin University of Science and Technology, Harbin 150080 (China); Xu, Chao; Xu, Yuheng [Department of the Applied Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

    2015-09-25

    Highlights: • In:Yb:Ho:LiNbO{sub 3} crystals were grown with various [Li]/[Nb] ratios. • The influence of [Li]/[Nb] ratios on the UV–VIS–NIR is investigated. • This UC process is three-photon process. • In:Yb:Ho:LiNbO{sub 3} crystals (Li/Nb = 1.38) is a promising material for 2 μm wavelength radiation. - Abstract: In:Yb:Ho:LiNbO{sub 3} crystals with high optical quality were grown by the Czochralski method with various ratios of [Li]/[Nb], that is 0.94, 1.05, 1.20 and 1.38 in the melt. The UV–VIS–NIR absorption spectra of In:Yb:Ho:LiNbO{sub 3} crystals were measured. The transition intensity parameters Ω{sub t} (t = 2, 4 and 6), spectroscopic quality factor (X) and the lifetimes of Ho{sup 3+} in In:Yb:Ho:LiNbO{sub 3} crystals were all evaluated by the Judd–Ofelt theory. The spectroscopic quality factor Ω{sub 4}/Ω{sub 6} of In:Yb:Ho:LiNbO{sub 3} crystals with the [Li]/[Nb] ratio of 1.38 was found to be 1.69, which is comparable with those found in widely used Ho{sup 3+} doped crystals. Furthermore, up-conversion emission spectra were determined and analyzed under 980 nm LD excitation in the In:Yb:Ho:LiNbO{sub 3} crystals. The results revealed that In:Yb:Ho:LiNbO{sub 3} crystal with the [Li]/[Nb] ratio of 1.38 is a promising material for 2 μm wavelength radiation.

  11. Secondary ion emission from CO2-H2O ice irradiated by energetic heavy ions: Part I. Measurement of the mass spectra

    Science.gov (United States)

    Farenzena, L. S.; Collado, V. M.; Ponciano, C. R.; da Silveira, E. F.; Wien, K.

    2005-05-01

    Secondary ion mass spectrometry is used to investigate ion emission from a frozen-gas mixture (T = 80-90 K) of CO2 and H2O bombarded by MeV nitrogen ions and by 252Cf fission fragments (FF). The aim of the experiments is to produce organic molecules in the highly excited material around the nuclear track and to detect them in the flux of sputtered particles. Such sputter processes are known to occur at the icy surfaces of planetary or interstellar objects. Time-of-flight (TOF) mass spectrometry is employed to identify the desorbed ions. Mass spectra of positive and negative ions were taken for several molecular H2O/CO2 ratios. In special, positive ions induced by MeV nitrogen beam were analyzed for 9 and 18% H2O concentrations of the CO2-H2O ice and negative ions for ~5% H2O. The ion peaks are separated to generate exclusive the spectra of CO2 specific ions, H2O specific ions and hybrid molecular ions, the latter ones corresponding to ions that contain mostly H and C atoms. In the mass range from 10 to 320 u, the latter exhibits 35 positive and 58 negative ions. The total yield of the positive ions is 0.35 and 0.57 ions/impact, respectively, and of negative ions 0.066 ions/impact. Unexpected effects of secondary ion sputtering yields on H2O/CO2 ratio are attributed to the influence of water molecules concentration on the ionization process.

  12. Monitoring Disinfection Byproduct Forming Potential with Simultaneous Absorbance Spectra and Fluorescence Excitation-Emission Mapping: Supporting Stage 2 EPA Regulation Monitoring Compliance

    Science.gov (United States)

    Gilmore, A. M.

    2011-12-01

    Water treatment plants in the United States will soon (by 2013 to 2013) be required to initialize enhanced monitoring for reducing disinfection by-products (DBPs) to meet the Stage 2 levels enforced by the EPA. The key to successfully meeting these requirements lies in the treatment plant's ability to deal with often dramatic source-water variations in natural organic matter (NOM) content. Whereas the regulated levels of NOM must be determined by measuring total organic carbon (TOC) often this parameter does not provide rapid or cost-effective qualitative or quantitative assessment of the various humic, fulvic and other aromatic NOM components. However, 2 main optical techniques namely UV absorbance and fluorescence excitation-emission mapping can be used for rapid assessment with precise identification of humic and fulvic components. This study presents data from a new type of instrument which simultaneously measures the UV-VIS absorbance spectrum and EEM. The rapid absorbance-EEM is facilitated by a single system that is more than 100 time faster than conventional scanning absorbance and fluoresence optical benches. The new system can continuously collect EEMs and absorbance spectra at a rate often greater than 1 per min with the extra capacity to monitor the UV254 absorbance and fluorescence emission spectrum excited at 254 nm in 4 ms intervals (an equivalent scan rate of 5.5 million nm/min). The EEM spectral data is corrected for all instrumental response factors including concentration dependent inner-filter effects. The accumulated EEM data sets can be modeled using conventional peak identification, PARAFAC and or PCA analysis of the fractionated samples to predict the trihalomethane forming potential (THMFP). This study compares the effectiveness of THFMP predictive models based on these three techniques and explains how these can be readily employed to facilitate the Stage 2 regulation compliance for DBP monitoring.

  13. The Infrared Spectra of Polycyclic Aromatic Hydrocarbons with Excess Peripheral H Atoms (H(sub n)-PAHs) and their Relation to the 3.4 and 6.9 Micrometer PAH Emission Features

    Science.gov (United States)

    Sandford, Scott A.; Bernstein, Max P.; Materese, Christopher K.

    2013-01-01

    A population of polycyclic aromatic hydrocarbons (PAHs) and related materials are thought to be responsible for the family of infrared emission features that are seen towards a wide variety of astrophysical environments. A potentially important subclass of these materials are polycyclic aromatic hydrocarbons whose edges contain excess H atoms (H(sub n)-PAHs). While it has been suggested that this type of compound may be present in the interstellar population, it has been difficult to properly assess this possibility because of a lack of suitable infrared laboratory spectra to assist with analysis of the astronomical data. We present the 4000-500 cm(exp -1) (2.5-20 micrometers) infrared spectra of 23 H(sub n)-PAHs and related molecules isolated in argon matrices, under conditions suitable for use in the interpretation of astronomical data. The spectra of molecules with mixed aromatic and aliphatic domains show unique characteristics that distinguish them from their fully aromatic PAH equivalents. We discuss the changes to the spectra of these types of molecules as they transition from fully aromatic to fully aliphatic forms. The implications for the interpretation of astronomical spectra are discussed with specific emphasis on the 3.4 and 6.9 micrometer features. Laboratory data is compared with emission spectra from IRAS 21282+5050, an object with normal PAH emission features, in addition to IRAS 22272+5435 and IRAS 0496+3429, two protoplanetary nebulae with abnormally large 3.4 micrometer features. We show that 'normal' PAH emission objects contain relatively few H(sub n)-PAHs in their emitter populations, but less evolved protoplanetary nebulae may contain significant abundances of these molecules.

  14. Emission spectra investigation of fs induced NPs probed by the ns laser pulse of a fs/ns DP-LIBS orthogonal configuration

    Energy Technology Data Exchange (ETDEWEB)

    Santagata, A. [CNR-IMIP, Unita Operativa di Potenza, Zona Industriale di Tito Scalo, Via S. Loja, Zona Ind., 85050 Tito Scalo, PZ (Italy)], E-mail: antonio.santagata@cnr.it; Albano, G.; Spera, D. [CNR-IMIP, Unita Operativa di Potenza, Zona Industriale di Tito Scalo, Via S. Loja, Zona Ind., 85050 Tito Scalo, PZ (Italy); Teghil, R. [Universita degli Studi della Basilicata, Dipartimento di Chimica, Via N. Sauro 85, 85100 Potenza (Italy); Villani, P.; Parisi, G.P. [CNR-IMIP, Unita Operativa di Potenza, Zona Industriale di Tito Scalo, Via S. Loja, Zona Ind., 85050 Tito Scalo, PZ (Italy); De Bonis, A. [Universita degli Studi della Basilicata, Dipartimento di Chimica, Via N. Sauro 85, 85100 Potenza (Italy); Sordelet, D.J. [Materials and Engineering Physics Program, Ames Laboratory, Iowa State University, Ames, IA (United States)

    2009-03-01

    A dual-pulse fs/ns laser induced breakdown spectroscopy configuration, where an initial 250 fs ablating pulsed laser followed by a delayed ns laser beam placed at a fixed distance, orthogonally with the expanding plasma plume, has been used in air on a Al{sub 65}Cu{sub 23}Fe{sub 12} quasicrystal. The obtained emission data were acquired with a set-up arrangement providing space detections, with a resolution up to 15 {mu}m, of the ns laser pulse generated signals. Assuming the fulfillment of local thermodynamic equilibrium conditions, the role played by the time lag between the two laser beams on the induced plasma excitation temperatures and electronic densities, as well as a space resolved process survey, has been followed. The spatial and time resolved spectra show, almost, steady values of the determined elementary plasma features with the development of nanoparticles occurring during the fs laser pulsed ablation process. The ns laser probe of the dual-pulse LIBS configuration here presented confirms that the nanoparticles induced can be largely widespread in both space and time whose compositions, overall, could retain the starting target stoichiometry. It is shown that these nanoparticles formation can actually take place at different times following the initial ultra-short laser beam incidence and that, especially at long inter-pulse delays (>100 {mu}s), modest compositional changes can be observed.

  15. Electromeric effect of substitution at 6th position in 2-(Furan-2-yl)-3-hydroxy-4 H-chromen-4-one (FHC) on the absorption and emission spectra

    Indian Academy of Sciences (India)

    Manisha Bansal; Ranbir Kaur

    2015-03-01

    Five 3-Hydroxychromones (3HCs), namely, 2-(furan-2-yl)-3-hydroxy-4H-chromen-4-one (FHC) and its four derivatives by substitution of -CH3, -OH, -NO2 and -Cl at 6th position were synthesized from their corresponding 2’-hydroxyacetophenone and furan-2-carboxaldehyde. Various spectral transitions of all these 3-hydroxychromones (3-HCs) have been assigned by interpreting their absorption spectra in cyclohexane, acetonitrile and methanol. It has been shown that the electromeric effects of substitution at 2nd and 6th positions on the 2–3 double bond in `C’ ring are similar but the effect on the double bond of 4-carbonyl group is opposite. It has been found that the substitution at 2nd position changes mainly the electron density directly at the 4-carbonyl group and substitution at 6th position changes the electron density of the `C’ ring, changing the overall dipole moment of the molecule, which in turn changes the electron density at the 4-carbonyl group. Emission spectral studies showed that the increase and decrease in dipole moment by substitution at 6th position with electron withdrawing group like NO2 and electron donating group like -CH3 and -OH, stabilizes and destabilizes the N* state in the polar solvents respectively

  16. A newly discovered DLA and associated Ly-alpha emission in the spectra of the gravitationally lensed quasar UM 673A,B

    CERN Document Server

    Cooke, Ryan; Steidel, Charles C; King, Lindsay J; Rudie, Gwen C; Rakic, Olivera

    2010-01-01

    The sightline to the brighter member of the gravitationally lensed quasar pair UM 673A,B intersects a damped Lyman-alpha system (DLA) at z = 1.62650 which, because of its low redshift, has not been recognised before. Our high quality echelle spectra of the pair, obtained with HIRES on the Keck I telescope, show a drop in neutral hydrogen column density N(H I) by a factor of at least 400 between UM 673A and B, indicating that the DLA's extent in this direction is much less than the 2.7 kpc separation between the two sightlines at z = 1.62650. By reassessing this new case together with published data on other QSO pairs, we conclude that the typical size (radius) of DLAs at these redshifts is R ~ (5 +/- 3) kpc, smaller than previously realised. Highly ionized gas associated with the DLA is more extended, as we find only small differences in the C IV absorption profiles between the two sightlines. Coincident with UM 673B, we detect a weak and narrow Ly-alpha emission line which we attribute to star formation acti...

  17. Vibration-rotation pattern in acetylene. II. Introduction of Coriolis coupling in the global model and analysis of emission spectra of hot acetylene around 3 microm.

    Science.gov (United States)

    Amyay, Badr; Robert, Séverine; Herman, Michel; Fayt, André; Raghavendra, Balakrishna; Moudens, Audrey; Thiévin, Jonathan; Rowe, Bertrand; Georges, Robert

    2009-09-21

    A high temperature source has been developed and coupled to a high resolution Fourier transform spectrometer to record emission spectra of acetylene around 3 mum up to 1455 K under Doppler limited resolution (0.015 cm(-1)). The nu(3)-ground state (GS) and nu(2)+nu(4)+nu(5) (Sigma(u) (+) and Delta(u))-GS bands and 76 related hot bands, counting e and f parities separately, are assigned using semiautomatic methods based on a global model to reproduce all related vibration-rotation states. Significantly higher J-values than previously reported are observed for 40 known substates while 37 new e or f vibrational substates, up to about 6000 cm(-1), are identified and characterized by vibration-rotation parameters. The 3 811 new or improved data resulting from the analysis are merged into the database presented by Robert et al. [Mol. Phys. 106, 2581 (2008)], now including 15 562 lines accessing vibrational states up to 8600 cm(-1). A global model, updated as compared to the one in the previous paper, allows all lines in the database to be simultaneously fitted, successfully. The updates are discussed taking into account, in particular, the systematic inclusion of Coriolis interaction.

  18. Emission spectra of luminous bacteria

    NARCIS (Netherlands)

    Spruit-van der Burg, A.

    1950-01-01

    The relation between the rate of photosynthesis and the pigment content was studied in seedlings of Avena sativa var. Victory. Etiolated seedlings were illuminated during different periods. Next, the rate of photosynthesis as well as the pigment concentrations were determined in the primary leaves.

  19. Franck-Condon Simulations including Anharmonicity of the Ã(1)A''-X̃(1)A' Absorption and Single Vibronic Level Emission Spectra of HSiCl and DSiCl.

    Science.gov (United States)

    Mok, Daniel W K; Lee, Edmond P F; Chau, Foo-Tim; Dyke, John M

    2009-03-10

    RCCSD(T) and/or CASSCF/MRCI calculations have been carried out on the X̃(1)A' and Ã(1)A'' states of HSiCl employing basis sets of up to the aug-cc-pV5Z quality. Contributions from core correlation and extrapolation to the complete basis set limit were included in determining the computed equilibrium geometrical parameters and relative electronic energy of these two states of HSiCl. Franck-Condon factors which include allowance for anharmonicity and Duschinsky rotation between these two states of HSiCl and DSiCl were calculated employing RCCSD(T) and CASSCF/MRCI potential energy functions, and were used to simulate the Ã(1)A'' ← X̃(1)A' absorption and Ã(1)A'' → X̃(1)A' single vibronic level (SVL) emission spectra of HSiCl and DSiCl. Simulated absorption and experimental LIF spectra, and simulated and observed Ã(1)A''(0,0,0) → X̃(1)A' SVL emission spectra, of HSiCl and DSiCl are in very good agreement. However, agreement between simulated and observed Ã(1)A''(0,1,0) → X̃(1)A' and Ã(1)A''(0,2,1) → X̃(1)A' SVL emission spectra of DSiCl is not as good. Preliminary calculations on low-lying excited states of HSiCl suggest that vibronic interaction between low-lying vibrational levels of the Ã(1)A'' state and highly excited vibrational levels of the ã(3)A'' is possible. Such vibronic interaction may change the character of the low-lying vibrational levels of the Ã(1)A'' state, which would lead to perturbation in the SVL emission spectra from these vibrational levels.

  20. THE INFRARED SPECTRA OF POLYCYCLIC AROMATIC HYDROCARBONS WITH EXCESS PERIPHERAL H ATOMS (H {sub n} -PAHs) AND THEIR RELATION TO THE 3.4 AND 6.9 {mu}m PAH EMISSION FEATURES

    Energy Technology Data Exchange (ETDEWEB)

    Sandford, Scott A.; Bernstein, Max P. [NASA-Ames Research Center, Mail Stop 245-6, Moffett Field, CA 94035-1000 (United States); Materese, Christopher K., E-mail: Scott.A.Sandford@nasa.gov [SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, CA 94043 (United States)

    2013-03-01

    Polycyclic aromatic hydrocarbons (PAHs) are likely responsible for the family of infrared emission features seen in a wide variety of astrophysical environments. A potentially important subclass of these materials are PAHs whose edges contain excess H atoms (H {sub n} -PAHs). This type of compound may be present in space, but it has been difficult to assess this possibility because of a lack of suitable laboratory spectra to assist with analysis of astronomical data. We present 4000-500 cm{sup -1} (2.5-20 {mu}m) infrared spectra of 23 H {sub n} -PAHs and related molecules isolated in argon matrices under conditions suitable for interpretation of astronomical data. Spectra of molecules with mixed aromatic and aliphatic domains show characteristics that distinguish them from fully aromatic PAH equivalents. Two major changes occur as PAHs become more hydrogenated: (1) aromatic C-H stretching bands near 3.3 {mu}m weaken and are replaced with stronger aliphatic bands near 3.4 {mu}m, and (2) aromatic C-H out-of-plane bending mode bands in the 11-15 {mu}m region shift and weaken concurrent with growth of a strong aliphatic -CH{sub 2}- deformation mode near 6.9 {mu}m. Implications for interpreting astronomical spectra are discussed with emphasis on the 3.4 and 6.9 {mu}m features. Laboratory data is compared with emission spectra from IRAS 21282+5050, an object with normal PAH emission features, and IRAS 22272+5435 and IRAS 0496+3429, two protoplanetary nebulae with abnormally large 3.4 {mu}m features. We show that 'normal' PAH emission objects contain relatively few H {sub n} -PAHs in their emitter populations, but less evolved protoplanetary nebulae may contain significant abundances of these molecules.

  1. Double pulse laser induced breakdown spectroscopy of a solid in water: Effect of hydrostatic pressure on laser induced plasma, cavitation bubble and emission spectra

    Science.gov (United States)

    López-Claros, M.; Dell'Aglio, M.; Gaudiuso, R.; Santagata, A.; De Giacomo, A.; Fortes, F. J.; Laserna, J. J.

    2017-07-01

    There is a growing interest in the development of sensors use in exploration of the deep ocean. Techniques for the chemical analysis of submerged solids are of special interest, as they show promise for subsea mining applications where a rapid sorting of materials found in the sea bottom would improve efficiency. Laser-Induced Breakdown Spectroscopy (LIBS) has demonstrated potential for this application thanks to its unique capability of providing the atomic composition of submerged solids. Here we present a study on the parameters that affect the spectral response of metallic targets in an oceanic pressure environment. Following laser excitation of the solid, the plasma persistence and the cavitation bubble size are considerably reduced as the hydrostatic pressure increases. These effects are of particular concern in dual pulse excitation as reported here, where a careful choice of the interpulse timing is required. Shadowgraphic images of the plasma demonstrate that cavitation bubbles are formed early after the plasma onset and that the effect of hydrostatic pressure is negligible during the early stage of plasma expansion. Contrarily to what is observed at atmospheric pressure, emission spectra observed at high pressures are characterized by self-absorbed atomic lines on continuum radiation resulting from strong radiative recombination in the electron-rich confined environment. This effect is much less evident with ionic lines due to the much higher energy of the levels involved and ionization energy of ions, as well as to the lower extent of absorption effects occurring in the inner part of the plasma, where ionized species are more abundant. As a result of the smaller shorter-lived cavitation bubble, the LIBS intensity enhancement resulting from dual pulse excitation is reduced when the applied pressure increases.

  2. Global peroxyacetyl nitrate (PAN retrieval in the upper troposphere from limb emission spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS

    Directory of Open Access Journals (Sweden)

    N. Glatthor

    2007-06-01

    Full Text Available We use limb emission spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS onboard the ENVIronmental SATellite (ENVISAT to derive the first global distribution of peroxyacetyl nitrate (PAN in the upper troposphere. PAN is generated in tropospheric air masses polluted by fuel combustion or biomass burning and acts as a reservoir and carrier of NOx in the cold free troposphere. PAN exhibits continuum-like broadband structures in the mid-infrared region and was retrieved in a contiguous analysis window covering the wavenumber region 775–800 cm−1. The interfering species CCl4, HCFC-22, H2O, ClONO2, CH3CCl3 and C2H2 were fitted along with PAN, whereas pre-fitted profiles were used to model the contribution of other contaminants like ozone. Sensitivity tests consisting in retrieval without consideration of PAN demonstrated the existence of PAN signatures in MIPAS spectra obtained in polluted air masses. The analysed dataset consists of 10 days between 4 October and 1 December 2003. This period covers the end of the biomass burning season in South America and South and East Africa, in which generally large amounts of pollutants are produced and distributed over wide areas of the southern hemispheric free troposphere. Indeed, elevated PAN amounts of 200–700 pptv were measured in a large plume extending from Brasil over the Southern Atlantic, Central and South Africa, the South Indian Ocean as far as Australia at altitudes between 8 and 16 km. Enhanced PAN values were also found in a much more restricted area between northern subtropical Africa and India. The most significant northern midlatitude PAN signal was detected in an area at 8 km altitude extending from China into the Chinese Sea. The average mid and high latitude PAN amounts found at 8 km were around 125 pptv in the northern, but only between 50 and 75 pptv in the

  3. Global peroxyacetyl nitrate (PAN retrieval in the upper troposphere from limb emission spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS

    Directory of Open Access Journals (Sweden)

    N. Glatthor

    2007-01-01

    Full Text Available We use limb emission spectra of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS onboard the ENVIronmental SATellite (ENVISAT to derive the first global distribution of peroxyacetyl nitrate (PAN in the upper troposphere. PAN is generated in tropospheric air masses polluted by fuel combustion or biomass burning and acts as a reservoir and carrier of NOx in the cold free troposphere. Since PAN exhibits continuum-like broadband structures in the mid-infrared region, we have applied a contiguous analysis window covering the wavenumber region 775–800 cm−1 for retrieval. The interfering species CCl4, HCFC-22, H2O, ClONO2, CH3CCl3 and C2H2 were fitted along with PAN, whereas pre-fitted profiles were used to model the contribution of other contaminants like ozone. Sensitivity tests consisting in retrieval without consideration of PAN have demonstrated the existence of PAN signatures in MIPAS spectra obtained from polluted air masses. The analysed dataset consists of 10 days between 4 October and 1 December 2003. This period covers the end of the biomass burning season in South America and South and East Africa, in which generally large amounts of pollutants are produced and distributed over wide areas in the southern hemispheric free troposphere. Elevated PAN amounts of 200–700 pptv were measured in a large plume extending from Brasil over the Southern Atlantic, Central and South Africa, the South Indian Ocean as far as Australia at altitudes between 8 and 16 km. Enhanced PAN values were also found in a much more restricted area between northern subtropical Africa and India. The most significant northern midlatitude PAN signal in MIPAS data is an area extending at 8 km altitude from China into the Chinese Sea. The average mid and high latitude PAN amounts found at 8 km were around 125 pptv in the northern, but only between 75 and

  4. Effects of Palagonitic Dust Coatings on Thermal Emission Spectra of Rocks and Minerals: Implications for Mineralogical Characterization of the Martian Surface by MGS-TES

    Science.gov (United States)

    Graff, T. G.; Morris, R.; Christensen, P.

    2001-01-01

    Thermal emission measurements on dust-coated rocks and minerals show that a 300 5m thick layer is required to mask emission from the substrate and that non-linear effects are present. Additional information is contained in the original extended abstract.

  5. Inequality spectra

    Science.gov (United States)

    Eliazar, Iddo

    2017-03-01

    Inequality indices are widely applied in economics and in the social sciences as quantitative measures of the socioeconomic inequality of human societies. The application of inequality indices extends to size-distributions at large, where these indices can be used as general gauges of statistical heterogeneity. Moreover, as inequality indices are plentiful, arrays of such indices facilitate high-detail quantification of statistical heterogeneity. In this paper we elevate from arrays of inequality indices to inequality spectra: continuums of inequality indices that are parameterized by a single control parameter. We present a general methodology of constructing Lorenz-based inequality spectra, apply the general methodology to establish four sets of inequality spectra, investigate the properties of these sets, and show how these sets generalize known inequality gauges such as: the Gini index, the extended Gini index, the Rényi index, and hill curves.

  6. Measurement of the 238U neutron-capture cross section and gamma-emission spectra from 10 eV to 100 keV using the DANCE detector at LANSCE

    Energy Technology Data Exchange (ETDEWEB)

    Ullmann, John L [Los Alamos National Laboratory; Couture, A J [Los Alamos National Laboratory; Keksis, A L [Los Alamos National Laboratory; Vieira, D J [Los Alamos National Laboratory; O' Donnell, J M [Los Alamos National Laboratory; Jandel, M [Los Alamos National Laboratory; Haight, R C [Los Alamos National Laboratory; Rundberg, R S [Los Alamos National Laboratory; Kawano, T [Los Alamos National Laboratory; Chyzh, A [NORTH CAROLINA STATE UNIV; Baramsai, B [NORTH CAROLINA STATE UNIV; Wu, C Y [LLNL; Mitchell, G E [NORTH CAROLINA STATE UNIV; Becker, J A [LLNL; Krticka, M [CHARLES UNIV

    2010-01-01

    A careful new measurement of the {sup 238}U(n,{gamma}) cross section from 10 eV to 100 keV has been made using the DANCE detector at LANSCE. DANCE is a 4{pi} calorimetric scintillator array consisting of 160 BaF{sub 2} crystals. Measurements were made on a 48 mg/cm{sup 2} depleted uranium target. The cross sections are in general good agreement with previous measurements. The gamma-ray emission spectra, as a function of gamma multiplicity, were also measured and compared to model calculations.

  7. Dissecting the Power Sources of Low-Luminosity Emission-Line Galaxy Nuclei via Comparison of HST-STIS and Ground-Based Spectra

    Science.gov (United States)

    Constantin, Anca; Shields, Joseph C.; Ho, Luis C.; Barth, Aaron J.; Filippenko, Alexei V.; Castillo, Christopher A.

    2015-12-01

    Using a sample of ∼100 nearby line-emitting galaxy nuclei, we have built the currently definitive atlas of spectroscopic measurements of Hα and neighboring emission lines at subarcsecond scales. We employ these data in a quantitative comparison of the nebular emission in Hubble Space Telescope (HST) and ground-based apertures, which offer an order-of-magnitude difference in contrast, and provide new statistical constraints on the degree to which transition objects and low-ionization nuclear emission-line regions (LINERs) are powered by an accreting black hole at ≲10 pc. We show that while the small-aperture observations clearly resolve the nebular emission, the aperture dependence in the line ratios is generally weak, and this can be explained by gradients in the density of the line-emitting gas: the higher densities in the more nuclear regions potentially flatten the excitation gradients, suppressing the forbidden emission. The transition objects show a threefold increase in the incidence of broad Hα emission in the high-resolution data, as well as the strongest density gradients, supporting the composite model for these systems as accreting sources surrounded by star-forming activity. The narrow-line LINERs appear to be the weaker counterparts of the Type 1 LINERs, where the low accretion rates cause the disappearance of the broad-line component. The enhanced sensitivity of the HST observations reveals a 30% increase in the incidence of accretion-powered systems at z ≈ 0. A comparison of the strength of the broad-line emission detected at different epochs implies potential broad-line variability on a decade-long timescale, with at least a factor of three in amplitude. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  8. DISSECTING THE POWER SOURCES OF LOW-LUMINOSITY EMISSION-LINE GALAXY NUCLEI VIA COMPARISON OF HST-STIS AND GROUND-BASED SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Constantin, Anca; Castillo, Christopher A. [Department of Physics and Astronomy, James Madison University, Harrisonburg, VA 22807 (United States); Shields, Joseph C. [Department of Physics and Astronomy, Ohio University, Athens, OH 45701 (United States); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Barth, Aaron J. [Department of Physics and Astronomy, University of California, Irvine, CA 92697-4575 (United States); Filippenko, Alexei V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

    2015-12-01

    Using a sample of ∼100 nearby line-emitting galaxy nuclei, we have built the currently definitive atlas of spectroscopic measurements of Hα and neighboring emission lines at subarcsecond scales. We employ these data in a quantitative comparison of the nebular emission in Hubble Space Telescope (HST) and ground-based apertures, which offer an order-of-magnitude difference in contrast, and provide new statistical constraints on the degree to which transition objects and low-ionization nuclear emission-line regions (LINERs) are powered by an accreting black hole at ≲10 pc. We show that while the small-aperture observations clearly resolve the nebular emission, the aperture dependence in the line ratios is generally weak, and this can be explained by gradients in the density of the line-emitting gas: the higher densities in the more nuclear regions potentially flatten the excitation gradients, suppressing the forbidden emission. The transition objects show a threefold increase in the incidence of broad Hα emission in the high-resolution data, as well as the strongest density gradients, supporting the composite model for these systems as accreting sources surrounded by star-forming activity. The narrow-line LINERs appear to be the weaker counterparts of the Type 1 LINERs, where the low accretion rates cause the disappearance of the broad-line component. The enhanced sensitivity of the HST observations reveals a 30% increase in the incidence of accretion-powered systems at z ≈ 0. A comparison of the strength of the broad-line emission detected at different epochs implies potential broad-line variability on a decade-long timescale, with at least a factor of three in amplitude.

  9. Dissecting the Power Sources of Low-Luminosity Emission-Line Galaxy Nuclei via Comparison of HST-STIS and Ground-Based Spectra

    CERN Document Server

    Constantin, Anca; Ho, Luis C; Barth, Aaron J; Filippenko, Alexei V; Castillo, Christopher A

    2015-01-01

    Using a sample of ~100 nearby line-emitting galaxy nuclei, we have built the currently definitive atlas of spectroscopic measurements of H_alpha and neighboring emission lines at subarcsecond scales. We employ these data in a quantitative comparison of the nebular emission in Hubble Space Telescope (HST) and ground-based apertures, which offer an order-of-magnitude difference in contrast, and provide new statistical constraints on the degree to which Transition Objects and low-ionization nuclear emission-line regions (LINERs) are powered by an accreting black hole at <10 pc. We show that while the small-aperture observations clearly resolve the nebular emission, the aperture dependence in the line ratios is generally weak, and this can be explained by gradients in the density of the line-emitting gas: the higher densities in the more nuclear regions potentially flatten the excitation gradients, suppressing the forbidden emission. The Transition Objects show a threefold increase in the incidence of broad H_...

  10. Photoemission spectra of CeAl[sub 3], CeBe[sub 13], CeSi[sub 2], and CeCu[sub 2]Si[sub 2]: Weights and widths of the 4[ital f] emission features

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, J.M. (Physics Department, University of California, Irvine, California 92717 (United States)); Arko, A.J.; Joyce, J.J.; Blyth, R.I.R.; Bartlett, R.J.; Canfield, P.C.; Fisk, Z. (Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)); Riseborough, P.S. (Physics Department, Polytechnic University, Brooklyn, New York 11201 (United States))

    1993-06-15

    We present valence-band photoemission spectra for CeAl[sub 3], CeBe[sub 13], CeSi[sub 2], CeCu[sub 2]Si[sub 2], and related conventional rare-earth counterpart compounds, taken at photon energies corresponding to the giant 4[ital d] resonance with resolution [similar to]150 meV. We take into account the 5[ital d] emission, which comprises 30% of the valence-band emission at the 4[ital d] resonance. We compare the resulting 4[ital f] emission to the predictions of the Anderson impurity model calculated in a low-order 1/[ital N] expansion, and including spin-orbit, crystal-field, and finite Coulomb correlation effects. The calculation gives order-of-magnitude fits to the data, but underestimates the spectral weight near the Fermi level by a factor of 2 and overestimates the width of the main [ital f] emission at 2 eV by a factor of 4. We argue that Ce photoemission remains an open problem and discuss several experimental and theoretical issues which need to be resolved to make further progress.

  11. Diagram X-ray emission spectra of a hollow atom: the Kh alpha1,2 and Kh beta1,3 hypersatellites of Fe.

    Science.gov (United States)

    Diamant, R; Huotari, S; Hämäläinen, K; Sharon, R; Kao, C C; Deutsch, M

    2003-11-07

    High-resolution Fe K(h) beta(1,3) and K(h) alpha(1,2) hypersatellite spectra were measured, using monochromatized synchrotron radiation photoexcitation. The lines' energies, splitting, excitation thresholds, and the K(h) alpha(1)/K(h) alpha(2) intensity ratio were derived with high accuracy. Having both spectra, not hitherto available for any atom with high resolution, allows separating out the energy shifts of the outer levels caused by a K shell spectator vacancy. Comparison with ab initio relativistic multiconfigurational Dirac-Fock calculations reveals that while the influence of relativity and QED effects is mostly accounted for, discrepancies remain in the lines' intensity ratio, which sensitively measures the intermediacy of the coupling. Similar discrepancies, of unknown origin, are found in the energy shifts of the outer levels due to the final-state K shell spectator vacancy.

  12. Effects of varying environmental conditions on emissivity spectra of bulk lunar soils: Application to Diviner thermal infrared observations of the Moon

    Science.gov (United States)

    Donaldson Hanna, K. L.; Greenhagen, B. T.; Patterson, W. R.; Pieters, C. M.; Mustard, J. F.; Bowles, N. E.; Paige, D. A.; Glotch, T. D.; Thompson, C.

    2017-02-01

    Currently, few thermal infrared measurements exist of fine particulate (Moon and other airless bodies. In this work, we present thermal infrared emissivity measurements of a suite of well-characterized Apollo lunar soils and a fine particulate (Moon for future laboratory measurements and to better interpret lunar surface compositions as observed by Diviner.

  13. TOMO3D: 3-D joint refraction and reflection traveltime tomography parallel code for active-source seismic data—synthetic test

    Science.gov (United States)

    Meléndez, A.; Korenaga, J.; Sallarès, V.; Miniussi, A.; Ranero, C. R.

    2015-10-01

    We present a new 3-D traveltime tomography code (TOMO3D) for the modelling of active-source seismic data that uses the arrival times of both refracted and reflected seismic phases to derive the velocity distribution and the geometry of reflecting boundaries in the subsurface. This code is based on its popular 2-D version TOMO2D from which it inherited the methods to solve the forward and inverse problems. The traveltime calculations are done using a hybrid ray-tracing technique combining the graph and bending methods. The LSQR algorithm is used to perform the iterative regularized inversion to improve the initial velocity and depth models. In order to cope with an increased computational demand due to the incorporation of the third dimension, the forward problem solver, which takes most of the run time (˜90 per cent in the test presented here), has been parallelized with a combination of multi-processing and message passing interface standards. This parallelization distributes the ray-tracing and traveltime calculations among available computational resources. The code's performance is illustrated with a realistic synthetic example, including a checkerboard anomaly and two reflectors, which simulates the geometry of a subduction zone. The code is designed to invert for a single reflector at a time. A data-driven layer-stripping strategy is proposed for cases involving multiple reflectors, and it is tested for the successive inversion of the two reflectors. Layers are bound by consecutive reflectors, and an initial velocity model for each inversion step incorporates the results from previous steps. This strategy poses simpler inversion problems at each step, allowing the recovery of strong velocity discontinuities that would otherwise be smoothened.

  14. Clinical evaluation of 3D/3D MRI-CBCT automatching on brain tumors for online patient setup verification - A step towards MRI-based treatment planning

    DEFF Research Database (Denmark)

    Buhl, S.K.; Duun-Christensen, Anne Katrine; Kristensen, B.H.;

    2010-01-01

    undergoing postoperative radiotherapy for malignant brain tumors received a weekly CBCT. In total 18 scans was matched with both CT and MRI as reference. The CBCT scans were acquired using a Clinac iX 2300 linear accelerator (Varian Medical Systems) with an On-Board Imager (OBI). Results. For the phantom...

  15. Fluorescence-excitation and emission spectra from LH2 antenna complexes of Rhodopseudomonas acidophila as a function of the sample preparation conditions.

    Science.gov (United States)

    Kunz, Ralf; Timpmann, Kõu; Southall, June; Cogdell, Richard J; Köhler, Jürgen; Freiberg, Arvi

    2013-10-10

    The high sensitivity of optical spectra of pigment-protein complexes to temperature and pressure is well known. In the present study, we have demonstrated the significant influence of the environments commonly used in bulk and single-molecule spectroscopic studies at low temperatures on the LH2 photosynthetic antenna complex from Rhodopseudomonas acidophila. A transfer of this LH2 complex from a bulk-buffer solution into a spin-coated polymer film results in a 189 cm(-1) blue shift of the B850 excitonic absorption band at 5 K. Within the molecular exciton model, the origin of this shift could be disentangled into three parts, namely to an increase of the local site energies, a contraction of the exciton band, and a decrease of the displacement energy.

  16. Normal incidence X-ray telescope power spectra of X-ray emission from solar active regions. I - Observations. II - Theory

    Science.gov (United States)

    Gomez, Daniel O.; Martens, Petrus C. H.; Golub, Leon

    1993-01-01

    Fourier analysis is applied to very high resolution image of coronal active regions obtained by the Normal Incidence X-Ray Telescope is used to find a broad isotropic power-law spectrum of the spatial distribution of soft X-ray intensities. Magnetic structures of all sizes are present down to the resolution limit of the instrument. Power spectra for the X-ray intensities of a sample of topologically different active regions are found which fall off with increasing wavenumber as 1/k-cubed. A model is presented that relates the basic features of coronal magnetic fluctuations to the subphotospheric hydrodynamic turbulence that generates them. The model is used to find a theoretical power spectrum for the X-ray intensity which falls off with increasing wavenumber as 1/k-cubed. The implications of a turbulent regime in active regions are discussed.

  17. Palagonitic Mars from Rock Rinds to Dust: Evidence from Visible, Near-IR, and Thermal Emission Spectra of Poorly Crystalline Materials

    Science.gov (United States)

    Morris, R. V.; Graff, T. G.; Mertzman, S. A.; Lane, M. D.; Christensen, P. R.

    2003-01-01

    Visible and near-IR (VNIR) spectral data for Martian bright regions are characterized by a general shape consisting of a ferric absorption edge extending from about 400 to 750 nm and relatively constant reflectivity extending from about 750 nm to beyond 2000 nm . Among terrestrial geologic materials, the best spectral analogues are certain palagonic tephras from Mauna Kea Volcano (Hawaii). By definition, palagonite is a yellow or orange isotropic mineraloid formed by hydration and devitrification of basaltic glass. The ferric pigment in palagonite is nanometer-sized ferric oxide particles (np-Ox) dispersed throughout the hydrated basaltic glass matrix. The hydration state of the np-Ox particles is not known, and the best Martian spectral analogues contain allophane-like materials and not crystalline phyllosilicates. We show here that laboratory VNIR and TES spectra of palagonitic alteration rinds developed on basaltic rocks are spectral endmembers that provide a consistent explanation for both VNIR and TES data of Martian dark regions.

  18. Microwave Power Spectra of Stimulated Phonon Emission and Spatio-Temporal Structures in an Optical-Wavelengths Acoustic Laser (Paramagnetic Phaser)

    CERN Document Server

    Makovetskii, D N

    2012-01-01

    A problem of self-organized motions in solid-state nonequilibrium media has been studied experimentally using methods of quantum acoustics. Generalized Poincare cross-sections of microwave power spectra (MPS) have been obtained in an optical-wavelengths acoustic laser (paramagnetic phaser) based on ruby crystal. Considerable narrowing of MPS and their autowave-like superslow motion have been observed under conditions of periodical pump modulation beyond the region of the phaser relaxation resonance. Some preliminar experimental results of this work were published in: Solid State Communications, Vol.90, No.8, P.501 (1994). An interpretation of the experimental data see arXiv:1101.0482v1 ; arXiv:cond-mat/0410460v1 ; arXiv:cond-mat/0303188v1 .

  19. Flower-Like Internal Emission Distribution of LEDs with Monolithic Integration of InGaN-based Quantum Wells Emitting Narrow Blue, Green, and Red Spectra.

    Science.gov (United States)

    Lee, Kwanjae; Choi, Ilgyu; Lee, Cheul-Ro; Chung, Tae-Hoon; Kim, Yoon Seok; Jeong, Kwang-Un; Chung, Dong Chul; Kim, Jin Soo

    2017-08-02

    We report a phosphor-free white light-emitting diodes (LED) realized by the monolithic integration of In0.18Ga0.82N/GaN (438 nm, blue), In0.26Ga0.74N/GaN (513 nm, green), and In0.45Ga0.55N/In0.13Ga0.87N (602 nm, red) quantum wells (QWs) as an active medium. The QWs corresponding to blue and green light were grown using a conventional growth mode. For the red spectral emission, five-stacked In0.45Ga0.55N/In0.13Ga0.87N QWs were realized by the so-called Ga-flow-interruption (Ga-FI) technique, wherein the Ga supply was periodically interrupted during the deposition of In0.3Ga0.7N to form an In0.45Ga0.55N well. The vertical and lateral distributions of the three different light emissions were investigated by fluorescence microscope (FM) images. The FM image measured at a focal point in the middle of the n-GaN cladding layer for the red-emitting LED shows that light emissions with flower-like patterns with six petals are periodically observed. The chromaticity coordinates of the electroluminescence spectrum for the white LEDs at an injection current of 80 mA are measured to be (0.316, 0.312), which is close to ideal white light. In contrast with phosphor-free white-light-emitting devices based on nanostructures, our white light device exhibits a mixture of three independent wavelengths by monolithically grown InGaN-based QWs, thus demonstrating a more facile technique to obtain white LEDs.

  20. Emission spectra of the sol-gel glass doped with europium(III) complexes of picolinic acid N-oxide-A new UV-light sensor

    Energy Technology Data Exchange (ETDEWEB)

    Godlewska, P. [Department of Bioorganic Chemistry, Institute of Chemistry and Food Technology, Faculty of Engineering and Economics, Lower Silesian University of Economics, Wroclaw (Poland); Macalik, L. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw (Poland); Hanuza, J. [Department of Bioorganic Chemistry, Institute of Chemistry and Food Technology, Faculty of Engineering and Economics, Lower Silesian University of Economics, Wroclaw (Poland); Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw (Poland)], E-mail: j.hanuza@int.pan.wroc.pl

    2008-02-28

    New europium complexes of picolinic acid N-oxides have been synthesised and introduced into sol-gel matrices. Their application as UV-light sensors has been considered. The sequence of the electronic levels for Eu{sup 3+} ions has been determined from the absorption and emission studies and assigned to the respective electron transitions. The lifetimes of the excited states have been detected and analysed. The role of the CT transition inside the picolinic ligand and its influence on the ligand to metal charge transfer (LMCT) have been discussed.

  1. Matrix formalism for calculation of the light beam intensity in stratified multilayered films, and its use in the analysis of emission spectra.

    Science.gov (United States)

    Ohta, K; Ishida, H

    1990-06-01

    Matrix formulation to describe the light propagation in stratified multilayered films has been extended to a system with phase incoherence. Several equations for the reflectance, transmittance, and light beam intensity in the film system are derived from the formulation. Some formulas previously proposed are corrected in reference to the present method. The beam intensity description is used for the calculation of light emissive power from multilayered films having a temperature gradient. It is found that the equations derived here are exactly equivalent to those derived from the radiative transfer equation. However, the present method is more tractable, and can be readily used for a film system with any number of layers.

  2. Detection of Broad H$\\alpha$ Emission Lines in the Late-time Spectra of a Hydrogen-poor Superluminous Supernova

    CERN Document Server

    Yan, Lin; Ofek, E; Gal-Yam, A; Mazzali, P; Perley, D; Vreeswijk, P; Leloudas, G; de Cia, A; Masci, F; Cenko, S B; Cao, Y; Kulkarni, S R; Nugent, P E; Rebbapragada, Umaa D; Woźniak, P R; Yaron, O

    2015-01-01

    iPTF13ehe is a hydrogen-poor superluminous supernova (SLSN) at z=0.3434, with properties similar to SN2007bi. It rises within (83-148)days (rest-frame) to reach a peak bolometric luminosity of 1.3x$10^{44}$erg/s, then decays very slowly at 0.015mag. per day. The measured ejecta velocity is 13000km/s. The inferred explosion characteristics, such as the ejecta mass (67-220$M_\\odot$), the total radiative and kinetic energy ($10^{51}$ & 2x$10^{53}$erg respectively), is typical of SLSN-R events. However, the late-time spectrum taken at +251days reveals a Balmer Halpha emission feature with broad and narrow components, which has never been detected before among other H-poor SLSNe. The broad component has a velocity width of ~4500km/s and has a ~300km/s blue-ward shift relative to the narrow component. We interpret this broad Halpha emission line as the interaction between the supernova ejecta and a H-rich circumstellar medium (CSM) shell, located at a distance of ~4x$10^{16}$cm from the explosion site. This eje...

  3. Exploratory analysis of excitation-emission matrix fluorescence spectra with self-organizing maps as a basis for determination of organic matter removal efficiency at water treatment works

    Science.gov (United States)

    Bieroza, Magdalena; Baker, Andy; Bridgeman, John

    2009-12-01

    In the paper, the self-organizing map (SOM) was employed for the exploratory analysis of fluorescence excitation-emission data characterizing organic matter removal efficiency at 16 water treatment works in the UK. Fluorescence spectroscopy was used to assess organic matter removal efficiency between raw and partially treated (clarified) water to provide an indication of the potential for disinfection by-products formation. Fluorescence spectroscopy was utilized to evaluate quantitative and qualitative properties of organic matter removal. However, the substantial amount of fluorescence data generated impeded the interpretation process. Therefore a robust SOM technique was used to examine the fluorescence data and to reveal patterns in data distribution and correlations between organic matter properties and fluorescence variables. It was found that the SOM provided a good discrimination between water treatment sites on the base of spectral properties of organic matter. The distances between the units of the SOM map were indicative of the similarity of the fluorescence samples and thus demonstrated the relative changes in organic matter content between raw and clarified water. The higher efficiency of organic matter removal was demonstrated for the larger distances between raw and clarified samples on the map. It was also shown that organic matter removal was highly dependent on the raw water fluorescence properties, with higher efficiencies for higher emission wavelengths in visible and UV humic-like fluorescence centers.

  4. First theoretical global line lists of ethylene (12C2H4) spectra for the temperature range 50-700 K in the far-infrared for quantification of absorption and emission in planetary atmospheres

    Science.gov (United States)

    Rey, M.; Delahaye, T.; Nikitin, A. V.; Tyuterev, Vl. G.

    2016-10-01

    We present the construction of complete and comprehensive ethylene line lists for the temperatures 50-700 K based on accurate ab initio potential and dipole moment surfaces and extensive first-principle calculations. Three lists spanning the [0-6400] cm-1 infrared region were built at T = 80, 160, and 296 K, and two lists in the range [0-5200] cm-1 were built at 500 and 700 K. For each of these five temperatures, we considered possible convergence problems to ensure reliable opacity calculations. Our final list at 700 K was computed up to J = 71 and contains almost 60 million lines for intensities I > 5 × 10-27 cm/molecule. Comparisons with experimental spectra carried out in this study showed that for the most active infrared bands, the accuracy of band centers in our theoretical lists is better on average than 0.3 cm-1, and the integrated absorbance errors in the intervals relevant for spectral analyses are about 1-3%. These lists can be applied to simulations of absorption and emission spectra, radiative and non-LTE processes, and opacity calculations for planetary and astrophysical applications. The lists are freely accessible through the TheoReTS information system at http://theorets.univ-reims.fr and http://theorets.tsu.ru

  5. Analysis of the absorption spectra of gas emission of patients with lung cancer and chronic obstructive pulmonary disease by laser optoacoustic spectroscopy

    Science.gov (United States)

    Bukreeva, Ekaterina B.; Bulanova, Anna A.; Kistenev, Yurii V.; Kuzmin, Dmitry A.; Tuzikov, Sergei A.; Yumov, Evgenii L.

    2013-02-01

    It is important to identify patients with chronic obstructive pulmonary disease (COPD) and lung cancer in the early stages of the disease. The method of laser opto-acoustic gas analysis, in this case, can act as a promising tool for diagnostics. The material for this study were the gas emission samples collected from patients and healthy volunteers - samples of exhaled air, swabs from teeth and cheeks. A set of material was formed three groups: healthy volunteers, patients with COPD, lung cancer patients. The resulting samples were analyzed by means of laser opto-acoustic gas analyzers: with intracavity location detector (ILPA-1), with extracavity location detector (LGA-2). Presentation of the results in an easy to visual form was performed using the method of elastic maps, based on the principal component analysis. The results of analysis show potentialities of usage of laser optoacoustic spectroscopy application to assess the status of patients with chronic obstructive pulmonary disease and lung cancer.

  6. Optimal fitting of Gaussian-apodized or under-resolved emission lines in Fourier transform spectra providing new insights on the velocity structure of NGC 6720

    Science.gov (United States)

    Martin, Thomas B.; Prunet, Simon; Drissen, Laurent

    2016-12-01

    An analysis of the kinematics of NGC 6720 is performed on the commissioning data obtained with SITELLE, the Canada-France-Hawaii Telescope's new imaging Fourier transform spectrometer. In order to measure carefully the small broadening effect of a shell expansion on an unresolved emission line, we have determined a computationally robust implementation of the convolution of a Gaussian with a sinc instrumental line shape which avoids arithmetic overflows. This model can be used to measure line broadening of typically a few km s-1 even at low spectral resolution (R halo in [N II] and Hα and found that the brightest bubbles are originating from two bipolar structures with a velocity difference of more than 35 km s-1 lying at the poles of a possibly unique halo shell expanding at a velocity of more than 15 km s-1.

  7. Experimental and theoretical studies of the VUV emission and absorption spectra of H{sub 2}, HD and D{sub 2} molecules; Etude experimentale et theorique des spectres d'emission et d'absorption VUV des molecules H{sub 2}, D{sub 2} et HD

    Energy Technology Data Exchange (ETDEWEB)

    Roudjane, M

    2007-12-15

    The aim of this thesis is to carry out an experimental study of the absorption and emission spectra of the D{sub 2} and HD isotopes, with high resolution, in the VUV domain and to supplement it by a theoretical study of the excited electronic states involved in the observed transitions. The emission spectra of HD and D{sub 2} are produced by Penning discharge source operating under low pressure and are recorded in the spectral range 78 - 170 nm. The recorded spectra contains more than 20.000 lines. The analysis of the spectrum consists in identifying and assigning the lines to the electronic transitions between energy levels of the molecule. The present analysis is based on our theoretical calculations of the ro-vibrational energy levels of the excited electronic states and the transition probabilities from these states towards the energy levels of the fundamental state. The theoretical results are obtained by resolving the coupled equations between the excited electronic states B{sup 1}{sigma}{sub u}{sup 1}, B'{sup 1}{sigma}{sub u}{sup 1}, C{sup 1}{pi}{sub u}{sup 1} and D{sup 1}{pi}{sub u}{sup 1}, taking into account the nonadiabatic couplings between these states, and they are obtained in the adiabatic approximation for the excited electronic states B''B-bar{sup 1}{sigma}{sub u}{sup +}, D'{sup 1}{pi}{sub u}{sup 1} and D''{sup 1}{pi}{sub u}{sup 1}. The equations are resolved using a modern method based on the discretization variables representation method. In addition, we have carried out a study of the absorption spectra of the HD and D{sub 2} molecules.

  8. Complex Spectra in Fusion Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Hellermann, M.G. von; Jaspers, R. [FOM-Institute for Plasma Physics Rijnhuizen, Nieuwegein (Netherlands); Bertschinger, G.; Biel, W.; Marchuk, O. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Plasmaphysik; Giroud, C.; Zastrow, K.D. [UKAEA Culham Laboratory Euratom Association, Abingdon (United Kingdom); Jupen, C. [Univ. of Lund (Sweden). Physics Dept.; O' Mullane, M.; Summers, H.P.; Whiteford, A. [Univ. of Strathclyde, Glasgow (United Kingdom). Applied Physics Dept.

    2005-12-15

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

  9. Meteors and meteorites spectra

    Science.gov (United States)

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

    2016-01-01

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

  10. Optimal fitting of gaussian-apodized or under-resolved emission lines in Fourier Transform spectra providing new insights on the velocity structure of NGC 6720

    Science.gov (United States)

    Martin, Thomas B.; Prunet, Simon; Drissen, Laurent

    2016-09-01

    An analysis of the kinematics of NGC 6720 is performed on the commissioning data obtained with SITELLE, the Canada-France-Hawaii Telescope's new imaging Fourier transform spectrometer. In order to measure carefully the small broadening effect of a shell expansion on an unresolved emission line, we have determined a computationally robust implementation of the convolution of a Gaussian with a sinc instrumental line shape which avoids arithmetic overflows. This model can be used to measure line broadening of typically a few km s-1 even at low spectral resolution (R less than 5000). We have also designed the corresponding set of Gaussian apodizing functions that are now used by ORBS, the SITELLE's reduction pipeline. We have implemented this model in ORCS, a fitting engine for SITELLE's data, and used it to derive the [S II] density map of the central part of the nebula. The study of the broadening of the [N II] lines shows that the Main Ring and the Central Lobe are two different shells with different expansion velocities. We have also derived deep and spatially resolved velocity maps of the Halo in [N II] and Hα and found that the brightest bubbles are originating from two bipolar structures with a velocity difference of more than 35 km s-1 lying at the poles of a possibly unique Halo shell expanding at a velocity of more than 15 km s-1.

  11. A search for iron emission lines in the Chandra X-ray spectra of neutron star low-mass X-ray binaries

    CERN Document Server

    Cackett, E M; Homan, J; Van der Klis, M; Lewin, W H G; Méndez, M; Raymond, J; Steeghs, D; Wijnands, R

    2008-01-01

    While iron emission lines are well studied in black hole systems, both in X-ray binaries and Active Galactic Nuclei, there has been less of a focus on these lines in neutron star low-mass X-ray binaries (LMXBs). However, recent observations with Suzaku and XMM-Newton have revealed broad asymmetric iron line profiles in 4 neutron star LMXBs, confirming an inner disk origin for these lines in neutron star systems. Here, we present a search for iron lines in 6 neutron star LMXBs. For each object we have simultaneous Chandra and RXTE observations at 2 separate epochs, allowing for both a high resolution spectrum, as well as broadband spectral coverage. Out of the six objects in the survey, we only find significant iron lines in two of the objects, GX 17+2 and GX 349+2. However, we cannot rule out that there are weak, broad lines present in the other sources. The equivalent width of the line in GX 17+2 is consistent between the 2 epochs, while in GX 349+2 the line equivalent width increases by a factor of ~3 betwe...

  12. Optimal fitting of gaussian-apodized or under-resolved emission lines in Fourier Transform spectra providing new insights on the velocity structure of NGC 6720

    CERN Document Server

    Martin, Thomas B; Drissen, Laurent

    2016-01-01

    An analysis of the kinematics of NGC 6720 is performed on the commissioning data obtained with SITELLE, the Canada-France-Hawaii Telescope's new imaging Fourier transform spectrometer. In order to measure carefully the small broadening effect of a shell expansion on an unresolved emission line, we have determined a computationally robust implementation of the convolution of a Gaussian with a sinc instrumental line shape which avoids arithmetic overflows. This model can be used to measure line broadening of typically a few km/s even at low spectral resolution (R less than 5000). We have also designed the corresponding set of Gaussian apodizing functions that are now used by ORBS, the SITELLE's reduction pipeline. We have implemented this model in ORCS, a fitting engine for SITELLE's data, and used it to derive the [SII] density map of the central part of the nebula. The study of the broadening of the [NII] lines shows that the Main Ring and the Central Lobe are two different shells with different expansion vel...

  13. Evaluation of secondary and prompt fission neutron spectra

    Energy Technology Data Exchange (ETDEWEB)

    Porodzinskij, Yu.V.; Sukhovitskij, E.Sh. [Radiation Physics and Chemistry Problems Inst., Minsk-Sosny (Belarus)

    1997-03-01

    A simple model allowing to split neutron emission spectra into reaction partials is suggested. Predicted spectra of (n,n`{gamma}), (n,n`f), etc appear to be much harder than usually evaluated. (author)

  14. Evaluation of secondary and prompt fission neutron spectra

    Energy Technology Data Exchange (ETDEWEB)

    Porodzinskij, Yu.V.; Sukhovitskij, E.Sh. [Radiation Physics and Chemistry Problems Inst., Minsk-Sosny (Belarus)

    1997-03-01

    A simple model allowing to split neutron emission spectra into reaction partials is suggested. Predicted spectra of (n,n`{gamma}), (n,n`f), etc appear to be much harder than usually evaluated. (author)

  15. Correlation between optical emission spectra and the process parameters of a 915 MHz microwave plasma CVD reactor used for depositing polycrystalline diamond coatings

    Indian Academy of Sciences (India)

    Awadesh Kumar Mallik; Sandip Bysakh; Someswar Dutta; Debabrata Basu

    2014-08-01

    In this paper, the hydrogen and hydrogen-methane mixed plasma have been generated inside a 33 cm diameter quartz bell jar with a low power (9 KW) and lower frequency 915 MHz microwave plasma chemical vapor deposition system. The reactor is being used for growing polycrystalline diamond (PCD) over large area (100 mm). The generated plasma is diagnosed by in situ optical emission spectroscopy method with wave length ranging from 200 to 900 nm. The effects of microwave power, chamber pressure and gas concentration on plasma characteristics have been studied in this work. Within the optical range, Balmer H, H, C2swan band and CH lines have been detected at the wavelengths of 655.95, 485.7, 515.82 and 430.17 nm, respectively. It has been observed that for hydrogen plasma, the amount of transition from hydrogen atom inner shell 3 to 2 (H) is almost constant with increasing microwave (MW) power (from 2000 to 2800 W) and pressure (from 15 to 30 Torr) initially, after that it increases with further increase of MW power and pressure, whereas, the transition from 4 to 2 (H) is slowly increased with increasing MW power and pressure. For hydrogen-methane plasma, intensities of C2 swan band, i.e., the transitions from D$^3\\Pi_\\text{g}$ to A$^3\\Pi_{\\mu}$ energy levels, are also increased with the increasing microwave power and reactor pressure. It has been observed that the radicals present in the plasma are affected by variation of different reactor parameters like pressure, MW power, CH4 concentration, etc.

  16. Absorption and Exciton Emission Spectra of Nanocrystalline Titanium Dioxide Thin Films%二氧化钛纳米晶薄膜的吸收光谱和激发发射光谱

    Institute of Scientific and Technical Information of China (English)

    孙振范; 李玉光

    2006-01-01

    由TiO2反胶束溶胶制备一系列TiO2纳米晶薄膜,对膜的吸收光谱和激发发射光谱研究表明制备的膜存在有二种模式的跃迁,直接跃迁和间接跃迁.由于厚膜中存在较强的表面相互作用,厚膜的直接跃迁禁带宽与薄膜相比发生了红移.在不同陈化时间,浸渍相同次数制得的膜具有相同的直接跃迁禁带宽.除浸渍一次的膜不存在间接跃迁外,所有的膜具有相同的间接跃迁禁带宽.所有的膜具有几乎相同的发射光谱模式.%A series of TiO2 nanocrystalline thin films were fabricated by using dip coating method from TiO2 reverse micelle solution. The studies on absorption and exciton emission spectra showed that both the indirect and direct transition exist in these TiO2 nanocrystalline thin films. A thick film has a red shift of direct transition bandgap than thin films due to the strong interface interaction. The films made at different aging time with same dip times have the same direct transition bandgaps. All the films have the same indirect transition bandgap, but those with one time dip have no indirect transition. All the films have almost the same patterns of photoluminescence spectra.

  17. Investigating the effect of landfill leachates on the characteristics of dissolved organic matter in groundwater using excitation-emission matrix fluorescence spectra coupled with fluorescence regional integration and self-organizing map.

    Science.gov (United States)

    He, Xiao-Song; Fan, Qin-Dong

    2016-11-01

    For the purpose of investigating the effect of landfill leachate on the characteristics of organic matter in groundwater, groundwater samples were collected near and in a landfill site, and dissolved organic matter (DOM) was extracted from the groundwater samples and characterized by excitation-emission matrix (EEM) fluorescence spectra combined with fluorescence regional integration (FRI) and self-organizing map (SOM). The results showed that the groundwater DOM comprised humic-, fulvic-, and protein-like substances. The concentration of humic-like matter showed no obvious variation for all groundwater except the sample collected in the landfill site. Fulvic-like substance content decreased when the groundwater was polluted by landfill leachates. There were two kinds of protein-like matter in the groundwater. One kind was bound to humic-like substances, and its content did not change along with groundwater pollution. However, the other kind was present as "free" molecules or else bound in proteins, and its concentration increased significantly when the groundwater was polluted by landfill leachates. The FRI and SOM methods both can characterize the composition and evolution of DOM in the groundwater. However, the SOM analysis can identify whether protein-like moieties was bound to humic-like matter.

  18. Dynamic Radio Spectra from two Fireballs

    CERN Document Server

    Obenberger, K S; Lin, C S; Dowell, J; Schinzel, F K; Stovall, K

    2015-01-01

    We present dynamic spectra from the LWA1 telescope of two large meteors (fireballs) observed to emit between 37 and 54 MHz. These spectra show the first ever recorded broadband measurements of this newly discovered VHF emission. The spectra show that the emission is smooth and steep, getting very bright at lower frequencies. We suggest that this signal is possibly emission of Langmuir waves and that these waves could be excited by a weak electron beam within the trail. The spectra of one fireball displays broadband temporal frequency sweeps. We suggest that these sweeps are evidence of individual expanding clumps of emitting plasma. While some of these proposed clumps may have formed at the very beginning of the fireball event, others must have formed seconds after the initial event.

  19. Reactor Neutrino Spectra

    OpenAIRE

    Hayes, A. C.; Vogel, Petr

    2016-01-01

    We present a review of the antineutrino spectra emitted from reactors. Knowledge of these spectra and their associated uncertainties is crucial for neutrino oscillation studies. The spectra used to date have been determined either by converting measured electron spectra to antineutrino spectra or by summing over all of the thousands of transitions that make up the spectra, using modern databases as input. The uncertainties in the subdominant corrections to β-decay plague both methods, and we ...

  20. Digital filtering of plume emission spectra

    Science.gov (United States)

    Madzsar, George C.

    1990-01-01

    Fourier transformation and digital filtering techniques were used to separate the superpositioned spectral phenomena observed in the exhaust plumes of liquid propellant rocket engines. Space shuttle main engine (SSME) spectral data were used to show that extraction of spectral lines in the spatial frequency domain does not introduce error, and extraction of the background continuum introduces only minimal error. Error introduced during band extraction could not be quantified due to poor spectrometer resolution. Based on the atomic and molecular species found in the SSME plume, it was determined that spectrometer resolution must be 0.03 nm for SSME plume spectral monitoring.

  1. Molecular Detectability in Exoplanetary Emission Spectra

    CERN Document Server

    Marcell, Tessenyi; Giorgio, Savini; Enzo, Pascale

    2013-01-01

    Of the many recently discovered worlds orbiting distant stars, very little is yet known of their chemical composition. With the arrival of new transit spectroscopy and direct imaging facilities, the question of molecular detectability as a function of signal-to-noise (SNR), spectral resolving power and type of planets has become critical. In this paper, we study the detectability of key molecules in the atmospheres of a range of planet types, and report on the minimum detectable abundances at fixed spectral resolving power and SNR. The planet types considered - hot Jupiters, hot super-Earths, warm Neptunes, temperate Jupiters and temperate super-Earths - cover most of the exoplanets characterisable today or in the near future. We focus on key atmospheric molecules, such as CH4, CO, CO2, NH3, H2O, C2H2, C2H6, HCN, H2S and PH3. We use two methods to assess the detectability of these molecules: a simple measurement of the deviation of the signal from the continuum, and an estimate of the level of confidence of a...

  2. 多针对板负电晕放电激发态N原子发射光谱研究%Study of Emission Spectra of N Atom Generated in Multi-Needle-to-Plate Corona Discharge

    Institute of Scientific and Technical Information of China (English)

    葛辉; 于然; 张路; 宓东; 朱益民

    2012-01-01

    The emission spectra of nitrogen (N) atom produced by multi-needle-to-plate negative corona discharge in air were detected successfully at one atmosphere, and the excited transition spectral line at 674. 5 nm with maximum value of relative intensity was selected to investigate the influences of air and electrical parameters on N atom relative density. The results indicate that N atom relative density in ionization region increases with the increase in power; decreases with increasing discharge gap and relative humidity; and with the increase in N2 content, the relative density of N active atom firstly increases and then decreases. Under present experimental conditions, the maximum value of N atom relative density appears at the axial distance from needle point r=1 mm.%在常压空气中,利用OES技术检测到负直流电晕放电等离子中激发态N原子发射光谱,并利用相对谱峰强度最大的674.5 nm N原子激发跃迁谱线研究了相关空气参数和电参数对其相对密度的影响.结果表明,电离区内N原子相对密度随注入功率的升高呈增加趋势;随电极间距和相对湿度的增加,其相对密度逐渐减小;随N2流量增加,其相对密度呈先增加再减小趋势.在实验条件下,当针尖轴向距离r=1 mm时,N原子相对密度出现最大值.

  3. Energy dependence of radioluminescence spectra from strontium titanate

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y., E-mail: wyfemail@gmail.com [School of Science, China University of Geosciences, Beijing 100083 (China); Zhao, Y.; Zhang, Z.; Zhao, C.; Wu, X. [School of Science, China University of Geosciences, Beijing 100083 (China); Finch, A.A. [Department of Earth & Environmental Sciences, University of St. Andrews, Fife KY16 9AL (United Kingdom); Townsend, P.D. [Physics Building, University of Sussex, Brighton BN1 9QH (United Kingdom)

    2015-10-15

    X-ray excited luminescence spectra of strontium titanate are reported over the temperature range from 20 to 300 K. The range includes several crystalline phases, each with different emission spectra. The signals are thermally quenched above ~220 K. There are spectral shifts and intensity changes around the temperatures associated with phase changes and overall there are nominally three spectral emission bands. A remarkable observation is that at fixed lower temperatures the spectra undergo major changes with the energy of the X-rays. A possible cause of the effect is discussed in terms of inner shell excitation from the K shell of the strontium. Comparisons with thermoluminescence spectra from the strontium titanate are reported. - Highlights: • Radioluminescence spectra of SrTiO{sub 3} are reported from 20 to 300 K. • X-ray luminescence spectra depend on crystal phase. • Direct evidence for inner shell excitation of Sr controlling emission spectra.

  4. Luminescent ion pairs with tunable emission colors for light-emitting devices and electrochromic switches† †Electronic supplementary information (ESI) available: Details of NMR and MS spectra. See DOI: 10.1039/c6sc02837c Click here for additional data file.

    Science.gov (United States)

    Guo, Song; Huang, Tianci; Liu, Shujuan; Zhang, Kenneth Yin; Yang, Huiran; Han, Jianmei

    2017-01-01

    Most recently, stimuli-responsive luminescent materials have attracted increasing interest because they can exhibit tunable emissive properties which are sensitive to external physical stimuli, such as light, temperature, force, and electric field. Among these stimuli, electric field is an important external stimulus. However, examples of electrochromic luminescent materials that exhibit emission color change induced by an electric field are limited. Herein, we have proposed a new strategy to develop electrochromic luminescent materials based on luminescent ion pairs. Six tunable emissive ion pairs (IP1–IP6) based on iridium(iii) complexes have been designed and synthesized. The emission spectra of ion pairs (IPs) show concentration dependence and the energy transfer process is very efficient between positive and negative ions. Interestingly, IP6 displayed white emission at a certain concentration in solution or solid state. Thus, in this contribution, UV-chip (365 nm) excited light-emitting diodes showing orange, light yellow and white emission colors were successfully fabricated. Furthermore, IPs displayed tunable and reversible electrochromic luminescence. For example, upon applying a voltage of 3 V onto the electrodes, the emission color of the solution of IP1 near the anode or cathode changed from yellow to red or green, respectively. Color tunable electrochromic luminescence has also been realized by using other IPs. Finally, a solid-film electrochromic switch device with a sandwiched structure using IP1 has been fabricated successfully, which exhibited fast and reversible emission color change. PMID:28451179

  5. Mn掺杂ZnO薄膜的软X射线发射光谱研究%Soft X-ray Emission Spectra of Mn-doped ZnO Thin Films

    Institute of Scientific and Technical Information of China (English)

    金晶; 张新夷; 周映雪

    2012-01-01

    利用先进光源(ALS)8.0.1光束线的软X射线荧光谱仪,对采用分子束外延(MBE)设备在200℃下生长的Zn0.97Mn0.03O和Zn0.67Mn0.33O薄膜样品进行了电子结构的研究.根据共振和非共振Mn L2,3边的X射线发射光谱,计算出Mn L2与Mn L3发射峰相对积分强度的比值(I(L2)/I(L3)),可知样品的铁磁性与自由d载流子的数目有关.在Zn0.97Mn0.03O中,Mn主要处于替代位置,并表现出较强的Coster-Kronig(C-K)跃迁效应,这说明样品中存在大量的自由d载流子.这些非局域的d载流子的行为类似于巡游电子,与Ruderman-Kittel-Kasuya-Yosid(RKKY)模型下计算得出的间隙Mn提供的4s电子,都可成为铁磁交换作用的媒介.在Zn0.67Mn0.33O中,自由d载流子的数目较少以及MnO团簇的存在是导致铁磁性向反铁磁性转变的主要原因.%The local electronic structures of Zn0.97Mn0.03O和Zn0.67Mn0.33O thin films prepared by a molecular beam epitaxy (MBE) at 200℃ were investigated by soft X-ray fluorescence spectrometer of beamline 8.0.1 of the Advanced Light Source (ALS). The special interest can be given to find the relationship between the electronic structure of Mn and magnetic properties of our samples. Analysis of the integral intensity ratio of Mn L2 to L3 emission lines (I(L2)//(L3)) from resonant and nonresonant Mn L2,3 X-ray emission spectra (XES) indicates that ferromagnet-ism (FM) is related to the free d charge carriers in the film. For ferromagnetic Zn0.97Mn0.03O sample, the majority of Mn atoms are incorporated at Zn substitutional sites and the film shows strong Coster-Kronig (C-K) transitions due to a large amount of free charge carriers available around Mn atoms. Both non-localized d charge carriers as itinerant electrons and 4s electrons from interstitial Mn obtained by Ruderman-Kittel-Kasuya-Yosid (RKKY) calculations can induce the ferromagnetic exchange interaction. However, the disappearance of FM in Zn0.67Mn0.33O sample can be explained in terms

  6. Gamma-ray burst spectra

    Science.gov (United States)

    Teegarden, B. J.

    1982-01-01

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

  7. Reactor Neutrino Spectra

    CERN Document Server

    Hayes, A C

    2016-01-01

    We present a review of the antineutrino spectra emitted from reactors. Knowledge of these and their associated uncertainties are crucial for neutrino oscillation studies. The spectra used to-date have been determined by either conversion of measured electron spectra to antineutrino spectra or by summing over all of the thousands of transitions that makeup the spectra using modern databases as input. The uncertainties in the subdominant corrections to beta-decay plague both methods, and we provide estimates of these uncertainties. Improving on current knowledge of the antineutrino spectra from reactors will require new experiments. Such experiments would also address the so-called reactor neutrino anomaly and the possible origin of the shoulder observed in the antineutrino spectra measured in recent high-statistics reactor neutrino experiments.

  8. Hot NH3 Spectra for Astrophysical Applications

    CERN Document Server

    Hargreaves, R J; Bernath, P F

    2011-01-01

    We present line lists for ammonia (NH$_{3}$) at high temperatures obtained by recording Fourier transform infrared emission spectra. Calibrated line lists are presented for twelve temperatures (300 -- 1300$^{\\circ}$C in 100$^{\\circ}$C intervals and 1370$^{\\circ}$C) and each line list covers the 740 -- 2100 cm$^{-1}$ range, which includes the majority of the $\

  9. [Effect of spectra on growth of chlorella and isochrysis].

    Science.gov (United States)

    Mao, An-Jun; Wang, Jing; Lin, Xue-Zheng; Meng, Ji-Wu

    2008-05-01

    Focusing on the speed and efficiency, the effects of different spectra on the growth of chlorella vulgaris and isochrysis galbana Parke 8701 were investigated by using monochromatic LED (light-emitting diode) and fluorescent lamp as light sources. It was concluded that continuous spectra accelerate the top-growth-rate, blue light has the best efficiency, and the combination of them can obtain a good balance of speed and efficiency. For the purpose of measuring spectra as a parameter of irradiation quantitatively, spectra-absorbability-coefficient defined as the quanta-absorbability- efficiency of spectra for algae was calculated by means of absorption spectra of algae and emission spectra of light sources. Compared with the experimental results the coefficients of different light sources have a positive correlation to their efficiency for growth, so the coefficient can be used to elementarily quantify the relation between the spectra and the efficiency for growth.

  10. Infrared emission from interstellar PAHs

    Science.gov (United States)

    Allamandola, L. J.; Tielens, A. G. G. M.; Barker, J. R.

    1987-01-01

    The mid-IR absorption and Raman spectra of polycyclic aromatic hydrocarbons (PAHs) and the mechanisms determining them are reviewed, and the implications for observations of similar emission spectra in interstellar clouds are considered. Topics addressed include the relationship between PAHs and amorphous C, the vibrational spectroscopy of PAHs, the molecular emission process, molecular anharmonicity, and the vibrational quasi-continuum. Extensive graphs, diagrams, and sample spectra are provided, and the interstellar emission bands are attributed to PAHs with 20-30 C atoms on the basis of the observed 3.3/3.4-micron intensity ratios.

  11. Action spectra again?

    Science.gov (United States)

    Coohill, T P

    1991-11-01

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

  12. Algorithms for classification of astronomical object spectra

    Science.gov (United States)

    Wasiewicz, P.; Szuppe, J.; Hryniewicz, K.

    2015-09-01

    Obtaining interesting celestial objects from tens of thousands or even millions of recorded optical-ultraviolet spectra depends not only on the data quality but also on the accuracy of spectra decomposition. Additionally rapidly growing data volumes demands higher computing power and/or more efficient algorithms implementations. In this paper we speed up the process of substracting iron transitions and fitting Gaussian functions to emission peaks utilising C++ and OpenCL methods together with the NOSQL database. In this paper we implemented typical astronomical methods of detecting peaks in comparison to our previous hybrid methods implemented with CUDA.

  13. Mid-infrared spectra of comet nuclei

    Science.gov (United States)

    Kelley, Michael S. P.; Woodward, Charles E.; Gehrz, Robert D.; Reach, William T.; Harker, David E.

    2017-03-01

    Comet nuclei and D-type asteroids have several similarities at optical and near-IR wavelengths, including near-featureless red reflectance spectra, and low albedos. Mineral identifications based on these characteristics are fraught with degeneracies, although some general trends can be identified. In contrast, spectral emissivity features in the mid-infrared provide important compositional information that might not otherwise be achievable. Jovian Trojan D-type asteroids have emissivity features strikingly similar to comet comae, suggesting that they have the same compositions and that the surfaces of the Trojans are highly porous. However, a direct comparison between a comet and asteroid surface has not been possible due to the paucity of spectra of comet nuclei at mid-infrared wavelengths. We present 5-35 μm thermal emission spectra of comets 10P/Tempel 2, and 49P/Arend-Rigaux observed with the Infrared Spectrograph on the Spitzer Space Telescope. Our analysis reveals no evidence for a coma or tail at the time of observation, suggesting the spectra are dominated by the comet nucleus. We fit each spectrum with the near-Earth asteroid thermal model (NEATM) and find sizes in agreement with previous values. However, the NEATM beaming parameters of the nuclei, 0.74-0.83, are systematically lower than the Jupiter-family comet population mean of 1.03 ± 0.11, derived from 16- and 22-μm photometry. We suggest this may be either an artifact of the spectral reduction, or the consequence of an emissivity low near 16 μm. When the spectra are normalized by the NEATM model, a weak 10-μm silicate plateau is evident, with a shape similar to those seen in mid-infrared spectra of D-type asteroids. A silicate plateau is also evident in previously published Spitzer spectra of the nucleus of comet 9P/Tempel 1. We compare, in detail, these comet nucleus emission features to those seen in spectra of the Jovian Trojan D-types (624) Hektor, (911) Agamemnon, and (1172) Aneas, as well

  14. {{\\rm{H}}}_{2}\\,X{}^{1}{{\\rm{\\Sigma }}}_{g}^{+}-c{}^{3}{{\\rm{\\Pi }}}_{u} Excitation by Electron Impact: Energies, Spectra, Emission Yields, Cross-sections, and H(1s) Kinetic Energy Distributions

    Science.gov (United States)

    Liu, Xianming; Shemansky, Donald E.; Yoshii, Jean; Liu, Melinda J.; Johnson, Paul V.; Malone, Charles P.; Khakoo, Murtadha A.

    2017-10-01

    The c{}3{{{\\Pi }}}u state of the hydrogen molecule has the second largest triplet-state excitation cross-section, and plays an important role in the heating of the upper thermospheres of outer planets by electron excitation. Precise energies of the H2, D2, and HD c{}3{{{\\Pi }}}u-(v,N) levels are calculated from highly accurate ab initio potential energy curves that include relativistic, radiative, and empirical non-adiabatic corrections. The emission yields are determined from predissociation rates and refined radiative transition probabilities. The excitation function and excitation cross-section of the c{}3{{{\\Pi }}}u state are extracted from previous theoretical calculations and experimental measurements. The emission cross-section is determined from the calculated emission yield and the extracted excitation cross-section. The kinetic energy (E k ) distributions of H atoms produced via the predissociation of the c{}3{{{\\Pi }}}u state, the c{}3{{{\\Pi }}}u- – b{}3{{{Σ }}}u+ dissociative emission by the magnetic dipole and electric quadrupole, and the c{}3{{{\\Pi }}}u – a{}3{{{Σ }}}g+ – b{}3{{{Σ }}}u+ cascade dissociative emission by the electric dipole are obtained. The predissociation of the c{}3{{{\\Pi }}}u+ and c{}3{{{\\Pi }}}u- states both produce H(1s) atoms with an average E k of ∼4.1 eV/atom, while the c{}3{{{\\Pi }}}u- – b{}3{{{Σ }}}u+ dissociative emissions by the magnetic dipole and electric quadrupole give an average E k of ∼1.0 and ∼0.8 eV/atom, respectively. The c{}3{{{\\Pi }}}u – a{}3{{{Σ }}}g+ – b{}3{{{Σ }}}u+ cascade and dissociative emission gives an average E k of ∼1.3 eV/atom. On average, each H2 excited to the c{}3{{{\\Pi }}}u state in an H2-dominated atmosphere deposits ∼7.1 eV into the atmosphere while each H2 directly excited to the a{}3{{{Σ }}}g+ and d{}3{{{\\Pi }}}u states contribute ∼2.3 and ∼3.3 eV, respectively, to the atmosphere. The spectral distribution of the calculated continuum emission

  15. Raman Spectra of Glasses

    Science.gov (United States)

    1986-11-30

    17), Raman spectra, plus a , . theoretical treatment of the data, f complex fluorozirconate 14 I anions in ZBLAN glasses and melts (16), and...based ZBLAN glasses ) 17. ICORS (International Conference on Raman Spectroscopy) Proceedings, London, England. Conferencf 5-9 Sep 88. (Molten silica...RESEARCH FINAL REPORT DTIC CONTRACT N00014-81-K-0501 &JELECTE 1 MAY 81 -- 30 NOV 86 EJJAN041989 V "RAMAN SPECTRA OF GLASSES " 0 During the five years of the

  16. SYNTHESIZED SPECTRA OF OPTICALLY THIN EMISSION LINES PRODUCED BY THE BIFROST STELLAR ATMOSPHERE CODE, INCLUDING NONEQUILIBRIUM IONIZATION EFFECTS: A STUDY OF THE INTENSITY, NONTHERMAL LINE WIDTHS, AND DOPPLER SHIFTS

    Energy Technology Data Exchange (ETDEWEB)

    Olluri, K.; Gudiksen, B. V.; Hansteen, V. H.; Pontieu, B. De, E-mail: kosovare.olluri@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, P. O. Box 1029 Blindern, NO-0315 Oslo (Norway)

    2015-03-20

    In recent years realistic 3D numerical models of the solar atmosphere have become available. The models attempt to recreate the solar atmosphere and mimic observations in the best way, in order to make it possible to couple complicated observations with physical properties such as the temperatures, densities, velocities, and magnetic fields. We here present a study of synthetic spectra created using the Bifrost code in order to assess how well they fit with previously taken solar data. A study of the synthetic intensity, nonthermal line widths, Doppler shifts, and correlations between any two of these three components of the spectra first assuming statistical equilibrium is made, followed by a report on some of the effects nonequilibrium ionization will have on the synthesized spectra. We find that the synthetic intensities compare well with the observations. The synthetic observations depend on the assumed resolution and point-spread function (PSF) of the instrument, and we find a large effect on the results, especially for intensity and nonthermal line width. The Doppler shifts produce the reported persistent redshifts for the transition region (TR) lines and blueshifts for the upper TR and corona lines. The nonthermal line widths reproduce the well-known turnoff point around (2–3) × 10{sup 5} K, but with much lower values than those observed. The nonthermal line widths tend to increase with decreasing assumed instrumental resolution, also when nonequilibrium ionization is included. Correlations between the nonthermal line width of any two TR line studies as reported by Chae et al. are reproduced, while the correlations of intensity to line width are reproduced only after applying a PSF to the data. Doppler shift correlations reported by Doschek for the TR lines and correlations of Doppler shift to nonthermal line width of the Fe xii{sub 19.5} line reported by Doschek et al. are reproduced.

  17. Development of a photonuclear activation file and measurement of delayed neutron spectra; Creation d'une bibliotheque d'activation photonucleaire et mesures de spectres d'emission de neutrons retardes

    Energy Technology Data Exchange (ETDEWEB)

    Giacri-Mauborgne, M.L

    2005-11-15

    This thesis work consists in two parts. The first part is the description of the creation of a photonuclear activation file which will be used to calculated photonuclear activation. To build this file we have used different data sources: evaluations but also calculations done using several cross sections codes (HMS-ALICE, GNASH, ABLA). This file contains photonuclear activation cross sections for more than 600 nuclides and fission fragments distributions for 30 actinides at tree different Bremsstrahlung energies and the delay neutron spectrum associated. These spectra are not in good agreement with experimental data. That is why we decided to launch measurement of delayed neutrons spectra from photofission. The second part of this thesis consists in demonstrating the possibility to do such measurements at the ELSA accelerator facility. To that purpose, we have developed the detection, the acquisition system and the analysis method of such spectra. These were tested for the measurement of the delayed neutron spectrum of uranium-238 after irradiation in a 2 MeV neutron flux. Finally, we have measured the delayed neutron spectrum of uranium-238 after irradiation in a 15 MeV Bremsstrahlung flux. We compare our results with experimental data. The experiment has allowed us to improve the value of {nu}{sub p}-bar with an absolute uncertainty below 7%, we propose {nu}{sub p}-bar = (3.03 {+-} 0.02) n/100 fissions, and to correct the Nikotin's parameters for the six group representation. Particularly, we have improved the data concerning the sixth group by taking into account results from different irradiation times.

  18. Cathodoluminescence spectra of gallium nitride nanorods.

    Science.gov (United States)

    Tsai, Chia-Chang; Li, Guan-Hua; Lin, Yuan-Ting; Chang, Ching-Wen; Wadekar, Paritosh; Chen, Quark Yung-Sung; Rigutti, Lorenzo; Tchernycheva, Maria; Julien, François Henri; Tu, Li-Wei

    2011-12-14

    Gallium nitride [GaN] nanorods grown on a Si(111) substrate at 720°C via plasma-assisted molecular beam epitaxy were studied by field-emission electron microscopy and cathodoluminescence [CL]. The surface topography and optical properties of the GaN nanorod cluster and single GaN nanorod were measured and discussed. The defect-related CL spectra of GaN nanorods and their dependence on temperature were investigated. The CL spectra along the length of the individual GaN nanorod were also studied. The results reveal that the 3.2-eV peak comes from the structural defect at the interface between the GaN nanorod and Si substrate. The surface state emission of the single GaN nanorod is stronger as the diameter of the GaN nanorod becomes smaller due to an increased surface-to-volume ratio.

  19. Broadband Eclipse Spectra of Exoplanets are Featureless

    CERN Document Server

    Hansen, C J; Cowan, N B

    2014-01-01

    Spectral retrieval methods leverage features in emission spectra to constrain the atmospheric composition and structure of transiting exoplanets. Most of the observed emission spectra consist of broadband photometric observations at a small number of wavelengths. We compare the Bayesian Information Criterion (BIC) of blackbody fits and spectral retrieval fits for all planets with eclipse measurements in multiple thermal wavebands, typically hot Jupiters with 2-4 observations. If the published error bars are taken at face value, then eight planets are significantly better fit by a spectral model than by a blackbody. In this under-constrained regime, however, photometric uncertainties directly impact one's ability to constrain atmospheric properties. By considering the handful of planets for which eclipse measurements have been repeated and/or reanalyzed, we obtain an empirical estimate of systematic uncertainties for broadband eclipse depths obtained with the Spitzer Space Telescope: sigma_sys = 5E-4. When thi...

  20. Mid-infrared spectra of comet nuclei

    CERN Document Server

    Kelley, Michael S P; Gehrz, Robert D; Reach, William T; Harker, David E

    2016-01-01

    Jovian Trojan D-type asteroids have mid-infrared emissivity features strikingly similar to comet comae, suggesting that they have the same compositions and that the surfaces of the Trojans are highly porous. However, a direct comparison between a comet and asteroid surface has not been possible due to the paucity of spectra of comet nuclei at mid-infrared wavelengths. We present 5-35 {\\mu}m thermal emission spectra of comets 10P/Tempel 2, and 49P/Arend-Rigaux observed with the Infrared Spectrograph on the Spitzer Space Telescope. Our analysis suggests the spectra are dominated by the comet nucleus. We fit each spectrum with the near-Earth asteroid thermal model (NEATM) and find sizes in agreement with previous values. However, the NEATM beaming parameters of the nuclei, 0.74 to 0.83, are systematically lower than the Jupiter-family comet population mean of 1.03+/-0.11, derived from 16- and 22-{\\mu}m photometry. When the spectra are normalized by the NEATM model, a weak 10-{\\mu}m silicate plateau is evident, w...

  1. Spectra and strains

    CERN Document Server

    Golyshev, V

    2008-01-01

    This is a blend of two informal reports on the activities of the seminar on Galois representations and mirror symmetry given at the Conference on classification problems and mirror duality at the Steklov Institute, in March 2006, and at the Seminar on Algebra, Geometry and Physics at MPI, in November 2007. We assess where we are on the issue of the spectra of Fano varieties, and state problems. We introduce higher dimensional irreducible analogues of dessins, the low ramified sheaves, and hypothesize that Fano spectra relate to their geometric conductors. We give a recipe to a physicist.

  2. Discrimination of phytoplankton classes using characteristic spectra of 3D fluorescence spectra.

    Science.gov (United States)

    Zhang, Qian-Qian; Lei, Shu-He; Wang, Xiu-Lin; Wang, Lei; Zhu, Chen-Jian

    2006-02-01

    The discrimination of phytoplankton classes using the characteristic fluorescence spectra extracted from three-dimensional fluorescence spectra was investigated. Single species cultures of 11 phytoplankton species, representing 5 major phytoplankton divisions, were used. The 3D fluorescence spectra of the cultures grown at different temperatures (20 and 15 degrees C) and illumination intensities (140, 80 and 30 microM m(-2) s(-1)) were measured and their feature extraction methods were explored. Ordering Rayleigh and Raman scattering data as zero, the obtained excitation-emission matrices were processed by both singular value decomposition (SVD) and trilinear decomposition methods. The resulting first principal component can be regarded as the characteristic spectrum of the original 3D fluorescence spectrum. The analysis shows that such characteristic spectra have a discriminatory capability. At different temperatures, the characteristic spectra of Isochrysis galbana, Platymonas helgolanidica and Skeletonema costatuma have high degrees of similarity to their own species samples, while the spectra similarities of Alexandrium tamarense, Prorocentrum dentatum, Pseudo-nitzschia pungens, Chaetoceros curvisetus, Ch. Debilis, Ch. Didymus and Synechococcus sp. are not as significant as the other three species. C. curvisetus, Ch. Debilis and Ch. Didymus, belonging to genus Chaetoceros, have identical spectra and cannot be discriminated at all. Regarding all six diatom species as one class, the average discriminant error rate is below 9%. It is worth mentioning that the diatom class can be distinguished from A. tamarense and P. dentatum, which belong to Dinophyta.

  3. Discrimination of phytoplankton classes using characteristic spectra of 3D fluorescence spectra

    Science.gov (United States)

    Zhang, Qian-Qian; Lei, Shu-He; Wang, Xiu-Lin; Wang, Lei; Zhu, Chen-Jian

    2006-02-01

    The discrimination of phytoplankton classes using the characteristic fluorescence spectra extracted from three-dimensional fluorescence spectra was investigated. Single species cultures of 11 phytoplankton species, representing 5 major phytoplankton divisions, were used. The 3D fluorescence spectra of the cultures grown at different temperatures (20 and 15 °C) and illumination intensities (140, 80 and 30 μM m -2 s -1) were measured and their feature extraction methods were explored. Ordering Rayleigh and Raman scattering data as zero, the obtained excitation-emission matrices were processed by both singular value decomposition (SVD) and trilinear decomposition methods. The resulting first principal component can be regarded as the characteristic spectrum of the original 3D fluorescence spectrum. The analysis shows that such characteristic spectra have a discriminatory capability. At different temperatures, the characteristic spectra of Isochrysis galbana, Platymonas helgolanidica and Skeletonema costatuma have high degrees of similarity to their own species samples, while the spectra similarities of Alexandrium tamarense, Prorocentrum dentatum, Pseudo-nitzschia pungens, Chaetoceros curvisetus, Ch. Debilis, Ch. Didymus and Synechococcus sp. are not as significant as the other three species. C. curvisetus, Ch. Debilis and Ch. Didymus, belonging to genus Chaetoceros, have identical spectra and cannot be discriminated at all. Regarding all six diatom species as one class, the average discriminant error rate is below 9%. It is worth mentioning that the diatom class can be distinguished from A. tamarense and P. dentatum, which belong to Dinophyta.

  4. Atomic Spectra Database (ASD)

    Science.gov (United States)

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

  5. Disk-averaged synthetic spectra of Mars

    Science.gov (United States)

    Tinetti, Giovanna; Meadows, Victoria S.; Crisp, David; Fong, William; Velusamy, Thangasamy; Snively, Heather

    2005-01-01

    The principal goal of the NASA Terrestrial Planet Finder (TPF) and European Space Agency's Darwin mission concepts is to directly detect and characterize extrasolar terrestrial (Earthsized) planets. This first generation of instruments is expected to provide disk-averaged spectra with modest spectral resolution and signal-to-noise. Here we use a spatially and spectrally resolved model of a Mars-like planet to study the detectability of a planet's surface and atmospheric properties from disk-averaged spectra. We explore the detectability as a function of spectral resolution and wavelength range, for both the proposed visible coronograph (TPFC) and mid-infrared interferometer (TPF-I/Darwin) architectures. At the core of our model is a spectrum-resolving (line-by-line) atmospheric/surface radiative transfer model. This model uses observational data as input to generate a database of spatially resolved synthetic spectra for a range of illumination conditions and viewing geometries. The model was validated against spectra recorded by the Mars Global Surveyor-Thermal Emission Spectrometer and the Mariner 9-Infrared Interferometer Spectrometer. Results presented here include disk-averaged synthetic spectra, light curves, and the spectral variability at visible and mid-infrared wavelengths for Mars as a function of viewing angle, illumination, and season. We also considered the differences in the spectral appearance of an increasingly ice-covered Mars, as a function of spectral resolution, signal-to-noise and integration time for both TPF-C and TPFI/ Darwin.

  6. Disk-averaged synthetic spectra of Mars

    Science.gov (United States)

    Tinetti, Giovanna; Meadows, Victoria S.; Crisp, David; Fong, William; Velusamy, Thangasamy; Snively, Heather

    2005-01-01

    The principal goal of the NASA Terrestrial Planet Finder (TPF) and European Space Agency's Darwin mission concepts is to directly detect and characterize extrasolar terrestrial (Earthsized) planets. This first generation of instruments is expected to provide disk-averaged spectra with modest spectral resolution and signal-to-noise. Here we use a spatially and spectrally resolved model of a Mars-like planet to study the detectability of a planet's surface and atmospheric properties from disk-averaged spectra. We explore the detectability as a function of spectral resolution and wavelength range, for both the proposed visible coronograph (TPFC) and mid-infrared interferometer (TPF-I/Darwin) architectures. At the core of our model is a spectrum-resolving (line-by-line) atmospheric/surface radiative transfer model. This model uses observational data as input to generate a database of spatially resolved synthetic spectra for a range of illumination conditions and viewing geometries. The model was validated against spectra recorded by the Mars Global Surveyor-Thermal Emission Spectrometer and the Mariner 9-Infrared Interferometer Spectrometer. Results presented here include disk-averaged synthetic spectra, light curves, and the spectral variability at visible and mid-infrared wavelengths for Mars as a function of viewing angle, illumination, and season. We also considered the differences in the spectral appearance of an increasingly ice-covered Mars, as a function of spectral resolution, signal-to-noise and integration time for both TPF-C and TPFI/ Darwin.

  7. Laboratory-based grain-shape models for simulating dust infrared spectra

    NARCIS (Netherlands)

    Mutschke, H.; Min, M.; Tamanai, A.

    2009-01-01

    Context. Analysis of thermal dust emission spectra for dust mineralogy and physical grain properties depends on comparison spectra, which are either laboratory-measured infrared extinction spectra or calculated extinction cross sections based on certain grain models. Often, the agreement between the

  8. EMPCA and Cluster Analysis of Quasar Spectra: Construction and Application to Simulated Spectra

    Science.gov (United States)

    Marrs, Adam; Leighly, Karen; Wagner, Cassidy; Macinnis, Francis

    2017-01-01

    Quasars have complex spectra with emission lines influenced by many factors. Therefore, to fully describe the spectrum requires specification of a large number of parameters, such as line equivalent width, blueshift, and ratios. Principal Component Analysis (PCA) aims to construct eigenvectors-or principal components-from the data with the goal of finding a few key parameters that can be used to predict the rest of the spectrum fairly well. Analysis of simulated quasar spectra was used to verify and justify our modified application of PCA.We used a variant of PCA called Weighted Expectation Maximization PCA (EMPCA; Bailey 2012) along with k-means cluster analysis to analyze simulated quasar spectra. Our approach combines both analytical methods to address two known problems with classical PCA. EMPCA uses weights to account for uncertainty and missing points in the spectra. K-means groups similar spectra together to address the nonlinearity of quasar spectra, specifically variance in blueshifts and widths of the emission lines.In producing and analyzing simulations, we first tested the effects of varying equivalent widths and blueshifts on the derived principal components, and explored the differences between standard PCA and EMPCA. We also tested the effects of varying signal-to-noise ratio. Next we used the results of fits to composite quasar spectra (see accompanying poster by Wagner et al.) to construct a set of realistic simulated spectra, and subjected those spectra to the EMPCA /k-means analysis. We concluded that our approach was validated when we found that the mean spectra from our k-means clusters derived from PCA projection coefficients reproduced the trends observed in the composite spectra.Furthermore, our method needed only two eigenvectors to identify both sets of correlations used to construct the simulations, as well as indicating the linear and nonlinear segments. Comparing this to regular PCA, which can require a dozen or more components, or to

  9. EMPCA and Cluster Analysis of Quasar Spectra: Application to SDSS Spectra

    Science.gov (United States)

    Leighly, Karen; Marrs, Adam; Wagner, Cassidy; Macinnis, Francis

    2017-01-01

    Accurate modeling of the quasar continuum is necessary to measure and analyze absorption lines. But quasar continua, in particular the emission lines, vary from object to object. Patterns in the variations allow a spectral principal component analysis (SPCA) approach using large samples of quasar spectra, e.g., from the SDSS. Then, a small number of the derived principal component spectra can be used to reconstruct an arbitrary quasar's continuum.A problem with this approach is that the number of principal components required to model an arbitrary quasar, usually 8 to 20 in the literature, is large. One reason why so many components are required is that SPCA implicitly assumes that spectra bins are independent. Quasar emission lines are spread over a range of spectral bins, and more importantly, can sometimes be blueshifted. So while the intrinsic variability may only be a function of a few physical parameters, the nonlinearity inherent in the variations from object to object requires a large number of prinicipal components to accurately model a quasar continuum.We present a modified approach. We perform a SPCA analysis, using an expectation-maximization algorithm by Bailey et al. 2012, which takes into account uncertainties and missing data. We project the sample spectra on the resulting eignevectors to obtain the projection coefficients. Reasoning that intriniscally similar spectra will have similar projection coefficients, we perform a cluster analysis on the projection coefficients. The results are used to divide the sample into groups of similar spectra. A second PCA analysis is then performed on each group. We find that many fewer eigenspectra are required to accurately model the spectra in each group. We apply this approach to several samples of quasars from the SDSS.

  10. Direct recovery of fluctuation spectra from tomographic shear spectra

    Science.gov (United States)

    Mezzetti, Marino; Bonometto, Silvio A.; Casarini, Luciano; Murante, Giuseppe

    2012-06-01

    Forthcoming experiments will enable us to determine high precision tomographic shear spectra. Matter density fluctuation spectra, at various z, should then be recovered from them, in order to constrain the model and determine the DE state equation. Available analytical expressions, however, do the opposite, enabling us to derive shear spectra from fluctuation spectra. Here we find the inverse expression, yielding density fluctuation spectra from observational tomographic shear spectra. The procedure involves SVD techniques for matrix inversion. We show in detail how the approach works and provide a few examples.

  11. Slit Spectra of Second Byurakan Survey Galaxies

    Science.gov (United States)

    Osterbrock, D. E.; Martel, A.

    1993-12-01

    Slit spectra have been obtained at Lick Observatory of 18 Seyfert galaxy candidates from the Second Byurakan Spectral Sky Survey (SBS). The great majority of them turned out to be Seyfert galaxies. The classifications and redshifts of all the galaxies are reported. Measurements of the intensity ratios of the emission lines used in classifying the galaxies are tabulated and plotted on diagnostic diagrams. The spectra of seven of the galaxies are described in detail. In general, our classification and redshift measurements are in very good accord with those of Lipovetsky, Stepanian, and their collaborators at the Special Astrophysical Observatory, showing that their results can be used in conjunction with the Lick results with little if any systematic difference between the two data sets. The importance of the SBS as a source of new Seyferts bridging the gap between low-redshift Seyfert galaxies and higher-luminosity QSOs is also emphasized.

  12. Curved Radio Spectra of Weak Cluster Shocks

    CERN Document Server

    Kang, Hyesung

    2015-01-01

    We explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud of fossil relativistic electrons in the cluster periphery. Such a scenario could explain uniformity of the surface brightness and spectral curvature in the integrated spectra of thin arc-like radio relics. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. The surface brightness profile of radio-emitting postshock region and the volume-integrated radio spectrum are calculated as well. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed $u_s \\sim 3,000 \\kms$ and sonic Mach number $M_s \\sim 3$. These shocks produce curved radio spectra that steepen gradually over $(0.1-10) \

  13. Atomic and Molecular Aspects of Astronomical Spectra

    CERN Document Server

    Sochi, Taha

    2012-01-01

    In the first section we present the atomic part where a C2+ atomic target was prepared and used to generate theoretical data to investigate recombination lines arising from electron-ion collisions in thin plasma. R-matrix method was used to describe the C2+ plus electron system. Theoretical data concerning bound and autoionizing states were generated in the intermediate-coupling approximation. The data were used to generate dielectronic recombination data for C+ which include transition lines, oscillator strengths, radiative transition probabilities, emissivities and dielectronic recombination coefficients. The data were cast in a line list containing 6187 optically-allowed transitions which include many C II lines observed in astronomical spectra. This line list was used to analyze the spectra from a number of astronomical objects, mainly planetary nebulae, and identify their electron temperature. The electron temperature investigation was also extended to include free electron energy analysis to investigate...

  14. Control spectra for Quito

    Science.gov (United States)

    Aguiar, Roberto; Rivas-Medina, Alicia; Caiza, Pablo; Quizanga, Diego

    2017-03-01

    The Metropolitan District of Quito is located on or very close to segments of reverse blind faults, Puengasí, Ilumbisí-La Bota, Carcelen-El Inca, Bellavista-Catequilla and Tangahuilla, making it one of the most seismically dangerous cities in the world. The city is divided into five areas: south, south-central, central, north-central and north. For each of the urban areas, elastic response spectra are presented in this paper, which are determined by utilizing some of the new models of the Pacific Earthquake Engineering Research Center (PEER) NGA-West2 program. These spectra are calculated considering the maximum magnitude that could be generated by the rupture of each fault segment, and taking into account the soil type that exists at different points of the city according to the Norma Ecuatoriana de la Construcción (2015). Subsequently, the recurrence period of earthquakes of high magnitude in each fault segment is determined from the physical parameters of the fault segments (size of the fault plane and slip rate) and the pattern of recurrence of type Gutenberg-Richter earthquakes with double truncation magnitude (Mmin and Mmax) is used.

  15. OPTICAL SPECTRA OF LOW-DIMENSIONAL SEMICONDUCTORS

    Institute of Scientific and Technical Information of China (English)

    Fu Y Chiragwandi Z; G(o..)thberg P; Willander M

    2003-01-01

    We have studied the optical spectra of low-dimensional semiconductor systems by calculating all possible optical transitions between electronic states. Optical absorption and emission have been obtained under different carrier population conditions and in different photon wavelengths. The line-shapes of the peaks in the optical spectrum are determined by the density of electronic states of the system, and the symmetries and intensities of these peaks can be improved by reducing the dimensionality of the system. Optical gain requires in general a population inversion, whereas for a quantum-dot system, there exists a threshold value of the population inversion.

  16. Study of optical absorption, visible emission and NIR–vis luminescence spectra of Tm{sup 3+}/Yb{sup 3+}, Ho{sup 3+}/Yb{sup 3+} and Tm{sup 3+}/Ho{sup 3+}/Yb{sup 3+} doped tellurite glasses

    Energy Technology Data Exchange (ETDEWEB)

    Seshadri, M., E-mail: seshumeruva@gmail.com [Institute of Physics, University of Campinas, UNICAMP, P.O. Box 6165, Campinas 13083-970 (Brazil); Barbosa, L.C.; Cordeiro, C.M.B.; Radha, M. [Institute of Physics, University of Campinas, UNICAMP, P.O. Box 6165, Campinas 13083-970 (Brazil); Sigoli, F.A. [Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, Campinas 13083-970 (Brazil); Ratnakaram, Y.C. [Department of Physics, Sri Venkateswara University, SVU, Tirupat 517502 (India)

    2015-10-15

    Tm{sup 3+}/Yb{sup 3+}, Ho{sup 3+}/Yb{sup 3+} co-doped and Tm{sup 3+}/Ho{sup 3+}/Yb{sup 3+} triply doped TeO{sub 2}–Bi{sub 2}O{sub 3}–ZnO–Li{sub 2}O–Nb{sub 2}O{sub 5} (TBZLN) tellurite glasses were prepared by melt quenching method. Judd–Ofelt intensity parameters (Ω{sub λ}, λ=2, 4 and 6), radiative transition probabilities, branching ratios and radiative lifetimes of Tm{sup 3+}, Ho{sup 3+} ions in co-doped TBZLN glasses were calculated from the optical absorption spectra. Excitation, visible luminescence and decay lifetimes in visible region were also investigated. The stimulated emission and gain cross-sections for the Tm{sup 3+}:{sup 3}F{sub 4}→{sup 3}H{sub 6} (1700 nm) and Ho{sup 3+}:{sup 5}I{sub 7}→{sup 5}I{sub 8} (1956 nm) transitions in co-doped TBZLN glasses have been analyzed and compared with those of other reported glasses. Up-conversion luminescence was observed in TBZLN glasses under 980 nm laser excitation and energy transfer mechanisms have been discussed. Finally, CIE color co-ordinates were calculated and it is observed that the color co-ordinates fall in blue and green regions for Tm{sup 3+}/Yb{sup 3+} and Ho{sup 3+}/Yb{sup 3+} co-doped TBZLN glasses, respectively. A subsequent shift in color co-ordinates from green to greenish-yellow region has been observed with an increase in the concentration (0.1, 0.5 and 1.0 mol%) of Tm{sup 3+} ions in Tm{sup 3+}/Ho{sup 3+}/Yb{sup 3+} triply doped TBZLN glasses. - Highlights: • High degree of covalecy of RE–O bond in co-doped TBZLN glasses was observed. • Tm{sup 3+}:{sup 1}D{sub 2}→{sup 3}F{sub 4} and Ho{sup 3+}:{sup 5}F{sub 4}({sup 5}S{sub 2})→{sup 5}I{sub 8} transitions show high emission cross-section. • Visible and strong 793 nm emission was observed when pumped by 980 nm diode laser. • Triply doped glasses exhibits tunable emission intensity by increasing Tm{sup 3+} ions.

  17. THERMODYNAMICS OF LIGHT EMISSION AND FREE-ENERGY STORAGE IN PHOTOSYNTHESIS

    OpenAIRE

    Ross, Robert T.; Calvin, Melvin

    2008-01-01

    A Planck law relationship between absorption and emission spectra is used to compute the fluorescence spectra of some photosynthetic systems from their absorption spectra. Calculated luminescence spectra of purple bacteria agree well but not perfectly with published experimental spectra. Application of the Planck law relation to published activation spectra for Systems I and II of spinach chloroplasts permits independent calculation of the luminescence spectra of the two systems; if the lumin...

  18. Sequencing BPS Spectra

    CERN Document Server

    Gukov, Sergei; Saberi, Ingmar; Stosic, Marko; Sulkowski, Piotr

    2015-01-01

    This paper provides both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explain from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincar\\'e polynomials in numerous examples. Among these structural properties is a novel "sliding" property, which can be explained by using (refined) modular $S$-matrix. This leads to the identifi...

  19. Optical Spectra of the High Voltage Erosive Water Discharge

    CERN Document Server

    Pirozerski, A L

    2008-01-01

    In the present paper kinetics of emission spectra of the high voltage erosive water discharge at near ultraviolet and visible spectral ranges has been investigated. Obtained results show a similarity of physical properties of this discharge (and of corresponding plasmoids) to that of some other types of erosional discharges which also result in the formation of dust-gas fireballs.

  20. A spectrograph for studying pulsed infrared laser spectra

    Energy Technology Data Exchange (ETDEWEB)

    Gorlin, G.B.; Filippov, V.N.; Komissarova, I.I.; Ostrobskii, U.I.; Ostrovskaya, G.V.; Paritskii, L.G.; Shevova, E.N.

    1982-01-01

    A spectrograph used to record the pulsed infrared spectra in a wavelength range which exceeds the sensitivity limits of standard photographic materials is described. The spectrograph is built using a standard scheme with mirror optics (f = 60 centimeters) and a diffraction grating 50 lines per millimeter. The recording process involves exposing the photomaterial to a pulsed emission source which is synchronized with a reference infrared emission source created using a purple relief photomaterial. The recording sensitivity is 10exp-2 joules per square centimeter. An interlaced pulsed CO2 laser emission spectrum is derived using the spectrograph.

  1. Quantum optimal control of photoelectron spectra and angular distributions

    CERN Document Server

    Goetz, R Esteban; Santra, Robin; Koch, Christiane P

    2016-01-01

    Photoelectron spectra and photoelectron angular distributions obtained in photoionization reveal important information on e.g. charge transfer or hole coherence in the parent ion. Here we show that optimal control of the underlying quantum dynamics can be used to enhance desired features in the photoelectron spectra and angular distributions. To this end, we combine Krotov's method for optimal control theory with the time-dependent configuration interaction singles formalism and a splitting approach to calculate photoelectron spectra and angular distributions. The optimization target can account for specific desired properties in the photoelectron angular distribution alone, in the photoelectron spectrum, or in both. We demonstrate the method for hydrogen and then apply it to argon under strong XUV radiation, maximizing the difference of emission into the upper and lower hemispheres, in order to realize directed electron emission in the XUV regime.

  2. Emission Trading

    OpenAIRE

    2009-01-01

    The work concerns Emission Trading Scheme from perspektive of taxes and accounting. I should show problems with emission trading. The work concerns practical example of trading with emission allowance.

  3. Theoretical Spectra of Terrestrial Exoplanet Surfaces

    CERN Document Server

    Hu, Renyu; Seager, Sara

    2012-01-01

    We investigate spectra of airless rocky exoplanets with a theoretical framework that self-consistently treats reflection and thermal emission. We find that a silicate surface on an exoplanet is spectroscopically detectable via prominent Si-O features in the thermal emission bands of 7 - 13 \\mu m and 15 - 25 \\mu m. The variation of brightness temperature due to the silicate features can be up to 20 K for an airless Earth analog, and the silicate features are wide enough to be distinguished from atmospheric features with relatively high-resolution spectra. The surface characterization thus provides a method to unambiguously identify a rocky exoplanet. Furthermore, identification of specific rocky surface types is possible with the planet's reflectance spectrum in near-infrared broad bands. A key parameter to observe is the difference between K band and J band geometric albedos (A_g (K)-A_g (J)): A_g (K)-A_g (J) > 0.2 indicates that more than half of the planet's surface has abundant mafic minerals, such as oliv...

  4. Non-Gaussian Spectra

    CERN Document Server

    Ferreira, P G; Ferreira, Pedro G.; Magueijo, Joao

    1997-01-01

    Gaussian cosmic microwave background skies are fully specified by the power spectrum. The conventional method of characterizing non-Gaussian skies is to evaluate higher order moments, the n-point functions and their Fourier transforms. We argue that this method is inefficient, due to the redundancy of information existing in the complete set of moments. In this paper we propose a set of new statistics or non-Gaussian spectra to be extracted out of the angular distribution of the Fourier transform of the temperature anisotropies in the small field limit. These statistics complement the power spectrum and act as localization, shape, and connectedness statistics. They quantify generic non-Gaussian structure, and may be used in more general image processing tasks. We concentrate on a subset of these statistics and argue that while they carry no information in Gaussian theories they may be the best arena for making predictions in some non-Gaussian theories. As examples of applications we consider superposed Gaussi...

  5. Theoretical investigation on the effect of protonation on the absorption and emission spectra of two amine-group-bearing, red "push-pull" emitters, 4-dimethylamino-4'-nitrostilbene and 4-(dicyanomethylene)-2-methyl-6-p-(dimethylamino) styryl-4H-pyran, by DFT and TDDFT calculations.

    Science.gov (United States)

    Petsalakis, I D; Georgiadou, D G; Vasilopoulou, M; Pistolis, G; Dimotikali, D; Argitis, P; Theodorakopoulos, G

    2010-05-06

    A theoretical investigation on the electronic structure of 4-dimethylamino-4'-nitrostilbene (DANS), 4-(dicyanomethylene)-2-methyl-6-p-(dimethylamino) styryl-4H-pyran (DCM), and their protonated forms is presented in an effort to rationalize recent experimental results on the tuning of the emitted color of organic light-emitting diodes through photochemically induced protonation. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations have been carried out on the neutral and protonated forms of DANS and DCM, employing both the B3LYP and the CAM-B3LYP functionals. It was found that the CAM-B3LYP functional leads to better agreement than the B3LYP of the calculated with the experimental absorption lambda(max) for DANS, whereas B3LYP is more appropriate than CAM-B3LYP for DCM. The results of the calculations aid in a rationalization of the observed differences of the spectra of DANS and DCM upon protonation, and in particular those differences that make DANS a more attractive system for absorbance and emission tuning.

  6. Orbits and emission spectra from the 2014 Camelopardalids

    CERN Document Server

    Madiedo, José M; Zamorano, Jaime; Izquierdo, Jaime; de Miguel, Alejandro Sánchez; Ocaña, Francisco; Ortiz, José L; Espartero, Francisco; Morillas, Lorenzo G; Cardeñosa, David; Moreno-Ibáñez, Manuel; Urzáiz, Marta

    2014-01-01

    We have analyzed the meteor activity associated with meteoroids of fresh dust trails of Comet 209P/LINEAR, which produced an outburst of the Camelopardalid meteor shower (IAU code #451, CAM) in May 2014. With this aim, we have employed an array of high-sensitivity CCD video devices and spectrographs deployed at 10 meteor observing stations in Spain in the framework of the Spanish Meteor Network (SPMN). Additional meteoroid flux data were obtained by means of two forward-scatter radio systems. The observed peak zenithal hourly rate (ZHR) was much lower than expected, of around 20 meteors h-1. Despite of the small meteor flux in the optical range, we have obtained precise atmospheric trajectory, radiant and orbital information for 11 meteor and fireball events associated with this stream. The ablation behaviour and low tensile strength calculated for these particles reveal that Camelopardalid meteoroids are very fragile, mostly pristine aggregates with strength similar to that of the Orionids and the Leonids. T...

  7. Heavy ozone enrichments from MIPAS limb emission spectra

    Directory of Open Access Journals (Sweden)

    A. Dudhia

    2009-11-01

    Full Text Available Vertical enrichment profiles of stratospheric heavy ozone (asymmetric and symmetric 50O3 isotopomers have been derived from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS. As a continuously operating satellite instrument, MIPAS has an advantage over previous measurements in providing global coverage over an extended time period, allowing the variations in enrichment to be determined. However, since the spectral features of the isotopomers are comparable with the magnitude of the instrument noise, a sequential estimation retrieval scheme has been used to average the measurements zonally.

    The magnitude of observed enrichments is ~10% in stratosphere, a value consistent with previous observations and lab measurements. The data indicate that asymmetric heavy ozone is significantly more enriched than the symmetric isotopomer and show latitudinal and vertical variations in both the asymmetric and symmetric 50O3 enrichments. Enrichments decrease with decreasing temperature, as previously noted, at midlatidudes and polar regions, while they increase with decreasing temperature in equatorial regions.

    MIPAS measurements contain also information on the asymmetric and symmetric 49O3 isotopomers. The enrichments of 49O3, obtained with the same sequential estimator approach, are much larger than the enrichments of 50O3, in contraddictions with previous results which predict larger enrichments for heavier isotopomers.

  8. Varying Faces of Photospheric Emission in Gamma-Ray Bursts

    CERN Document Server

    Axelsson, M

    2015-01-01

    Among the more than 1000 gamma-ray bursts observed by the Fermi Gamma-ray Space Telescope, a large fraction show narrow and hard spectra inconsistent with non-thermal emission, signifying optically thick emission from the photosphere. However, only a few of these bursts have spectra consistent with a pure Planck function. We will discuss the observational features of photospheric emission in these GRBs as well as in the ones showing multi-component spectra. We interpret the observations in light of models of subphotospheric dissipation, geometrical broadening and multi-zone emission, and show what we can learn about the dissipation mechanism and properties of GRB jets.

  9. Energetic solar electron spectra and gamma-ray observations

    Science.gov (United States)

    Dröge, Wolfgang

    1996-06-01

    We analyze solar energetic electron events measured with particle detectors on board of the ISEE-3 (ICE) and Helios 1 and 2 spacecraft. Energy spectra in the range 0.1 to tens of MeV are generated applying the results of a careful re-examination of the electron response function of the instruments. The spectral shapes of events observed simultaneously, among them five on all three s/c, are in very good agreement inspite of the sometimes considerable difference in azimuthal and radial distances of the s/c with respect to the flare. These findings suggest that transport processes at the Sun and in the interplanetary medium depend only weakly on the electron energy and that the observed spectra are representative of the accelerated electron spectra at the Sun. A comparison of the electron spectra with SMM gamma-ray spectra gives evidence for the existence of different acceleration and emission mechanism in flares with long (LDEs) and short duration (SDEs) soft X-ray emission.

  10. Measurements and parameterization of neutron energy spectra from targets bombarded with 120 GeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Kajimoto, T., E-mail: kajimoto@hiroshima-u.ac.jp [Hiroshima University, Kagamiyama, Higashi-hiroshima 739-8527 (Japan); Shigyo, N. [Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Sanami, T. [High Energy Accelerator Research Organization, Oho, Tsukuba, Ibaraki 305-0801 (Japan); Iwamoto, Y. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Hagiwara, M. [High Energy Accelerator Research Organization, Oho, Tsukuba, Ibaraki 305-0801 (Japan); Lee, H.S. [Pohang Accelerator Laboratory, POSTECH, Pohang, Kyungbuk 790-784 (Korea, Republic of); Soha, A.; Ramberg, E.; Coleman, R.; Jensen, D.; Leveling, A.; Mokhov, N.V.; Boehnlein, D.; Vaziri, K. [Fermi National Accelerator Laboratory, Batavia, IL 60510-5011 (United States); Sakamoto, Y. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Ishibashi, K. [Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Nakashima, H. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

    2014-10-15

    Highlights: •Neutron energy spectra from targets bombarded with 120 GeV protons were measured. •The neutron energy was determined with the time-of-flight technique. •The measured spectra were compared with those calculated by PHITS and FLUKA. •Large differences were found between measured and calculated spectra. •The study shows the need to improve models for neutron production in the high energy region. -- Abstract: The energy spectra of neutrons were measured by a time-of-flight method for 120 GeV protons on thick graphite, aluminum, copper, and tungsten targets with an NE213 scintillator at the Fermilab Test Beam Facility. Neutron energy spectra were obtained between 25 and 3000 MeV at emission angles of 30°, 45°, 120°, and 150°. The spectra were parameterized as neutron emissions from three moving sources and then compared with theoretical spectra calculated by PHITS and FLUKA codes. The yields of the theoretical spectra were substantially underestimated compared with the yields of measured spectra. The integrated neutron yields from 25 to 3000 MeV calculated with PHITS code were 16–36% of the experimental yields and those calculated with FLUKA code were 26–57% of the experimental yields for all targets and emission angles.

  11. The Berlin emissivity database (BED)

    Science.gov (United States)

    Maturilli, A.; Helbert, J.; Moroz, L.

    2008-03-01

    Remote-sensing infrared spectroscopy is the principal field of investigation for planetary surfaces composition. Past, present and future missions to the solar system bodies include in their payload, instruments measuring the emerging radiation in the infrared range. Apart from measuring the reflected radiance, more and more spacecrafts are equipped with instruments measuring directly the emitted radiation from the planetary surface. The emitted radiation is not only a function of the composition of the material but also of its texture and especially the grain size distribution. For the interpretation of the measured data an emissivity spectral library of planetary analogue materials in grain size fractions appropriate for planetary surfaces is needed. The Berlin emissivity database (BED) presented here is focused on relatively fine-grained size separates, providing thereby a realistic basis for the interpretation of thermal emission spectra of planetary regoliths. The BED is therefore complimentary to existing thermal emission libraries, like the ASU library for example. BED currently contains emissivity spectra of plagioclase and potassium feldspars, low Ca and high Ca pyroxenes, olivine, elemental sulfur, Martian analogue minerals and volcanic soils, and a lunar highland soil sample measured in the wavelength range from 7 to 22 μm as a function of particle size. For each sample we measured the spectra of four particle size separates ranging from <25 to 250 μm. The device we used is built at DLR (Berlin) and is coupled to a Fourier-transform infrared spectrometer Bruker IFS 88 purged with dry air and equipped with a nitrogen-cooled MCT detector. All spectra were acquired with a spectral resolution of 4 cm -1. We are currently working on upgrading our emissivity facility. A new spectrometer (Bruker VERTEX 80 V) and new detectors will allow us to measure the emissivity of samples in the wavelength range from 1 to 50 μm in a vacuum environment. This will be

  12. Photoluminescence spectra of some ternary and quaternary chalcopyrite semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Abou-Elfotouh, F.; Dunlavy, D.J.; Kazmerski, L.L.; Albin, D.; Bachman, K.J.; Menner, R.

    1988-05-01

    Photoluminescence (PL) emission spectra of single crystals and thin films of CuGa/sub x/In/sub 1/..sqrt../sub x/Se/sub 2/ compounds have been investigated at various measuring temperatures, and compared with the emission from CuGaSe/sub 2/ and CuInSe/sub 2/. The observed PL spectra consisted of two groups of emission lines: the near-band-gap group (A) and the lower energy group (B). It was found that the type of emission obtained is determined by the amount of stoichiometry and molecularity deviations. The PL data also showed a correspondence between the defect related transitions from the CuGa/sub x/In/sub 1/..sqrt../sub x/Se/sub 2/ solid solution and CuGaSe/sub 2/ for x<0.5. Based on the intrinsic defect states in the two components CuInSe/sub 2/ and CuGaSe/sub 2/, the predominant defect states transitions in the solid solution are defined for the m<1 and ..delta..S>0. Interpretation of the PL spectra of Se-deficient compounds with m>1 are rather complicated, and much work remains to be done before the defect chemistry of CuGa/sub x/In/sub 1/..sqrt../sub x/Se/sub 2/ could be fully understood.

  13. Pileup correction of microdosimetric spectra

    CERN Document Server

    Langen, K M; Lennox, A J; Kroc, T K; De Luca, P M

    2002-01-01

    Microdosimetric spectra were measured at the Fermilab neutron therapy facility using low pressure proportional counters operated in pulse mode. The neutron beam has a very low duty cycle (<0.1%) and consequently a high instantaneous dose rate which causes distortions of the microdosimetric spectra due to pulse pileup. The determination of undistorted spectra at this facility necessitated (i) the modified operation of the proton accelerator to reduce the instantaneous dose rate and (ii) the establishment of a computational procedure to correct the measured spectra for remaining pileup distortions. In support of the latter effort, two different pileup simulation algorithms using analytical and Monte-Carlo-based approaches were developed. While the analytical algorithm allows a detailed analysis of pileup processes it only treats two-pulse and three-pulse pileup and its validity is hence restricted. A Monte-Carlo-based pileup algorithm was developed that inherently treats all degrees of pileup. This algorithm...

  14. Correlation Functions and Power Spectra

    DEFF Research Database (Denmark)

    Larsen, Jan

    2006-01-01

    The present lecture note is a supplement to the textbook Digital Signal Processing by J. Proakis and D.G. Manolakis used in the IMM/DTU course 02451 Digital Signal Processing and provides an extended discussion of correlation functions and power spectra. The definitions of correlation functions...... and spectra for discrete-time and continuous-time (analog) signals are pretty similar. Consequently, we confine the discussion mainly to real discrete-time signals. The Appendix contains detailed definitions and properties of correlation functions and spectra for analog as well as discrete-time signals....... It is possible to define correlation functions and associated spectra for aperiodic, periodic and random signals although the interpretation is different. Moreover, we will discuss correlation functions when mixing these basic signal types. In addition, the note include several examples for the purpose...

  15. Absorption Spectra of Astaxanthin Aggregates

    CERN Document Server

    Olsina, Jan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas

    2012-01-01

    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption maximum of monomeric astaxanthin (470-495 nm depending on solvent) are caused by excitonic interaction between aggregated molecules. We applied molecular dynamics simulations to elucidate structure of astaxanthin dimer in water, and the resulting structure was used as a basis for calculations of absorption spectra. Absorption spectra of astaxanthin aggregates in hydrated dimethylsulfoxide were calculated using molecular exciton model with the resonance interaction energy between astaxanthin monomers constrained by semi-e...

  16. Infrared spectra of mineral species

    CERN Document Server

    Chukanov, Nikita V

    2014-01-01

    This book details more than 3,000 IR spectra of more than 2,000 mineral species collected during last 30 years. It features full descriptions and analytical data of each sample for which IR spectrum was obtained.

  17. PAHFIT: Properties of PAH Emission

    Science.gov (United States)

    Smith, J. D.; Draine, Bruce

    2012-10-01

    PAHFIT is an IDL tool for decomposing Spitzer IRS spectra of PAH emission sources, with a special emphasis on the careful recovery of ambiguous silicate absorption, and weak, blended dust emission features. PAHFIT is primarily designed for use with full 5-35 micron Spitzer low-resolution IRS spectra. PAHFIT is a flexible tool for fitting spectra, and you can add or disable features, compute combined flux bands, change fitting limits, etc., without changing the code. PAHFIT uses a simple, physically-motivated model, consisting of starlight, thermal dust continuum in a small number of fixed temperature bins, resolved dust features and feature blends, prominent emission lines (which themselves can be blended with dust features), as well as simple fully-mixed or screen dust extinction, dominated by the silicate absorption bands at 9.7 and 18 microns. Most model components are held fixed or are tightly constrained. PAHFIT uses Drude profiles to recover the full strength of dust emission features and blends, including the significant power in the wings of the broad emission profiles. This means the resulting feature strengths are larger (by factors of 2-4) than are recovered by methods which estimate the underlying continuum using line segments or spline curves fit through fiducial wavelength anchors.

  18. Radioactive sample effects on EDXRF spectra

    Energy Technology Data Exchange (ETDEWEB)

    Worley, Christopher G [Los Alamos National Laboratory

    2008-01-01

    Energy dispersive X-ray fluorescence (EDXRF) is a rapid, straightforward method to determine sample elemental composition. A spectrum can be collected in a few minutes or less, and elemental content can be determined easily if there is adequate energy resolution. Radioactive alpha emitters, however, emit X-rays during the alpha decay process that complicate spectral interpretation. This is particularly noticeable when using a portable instrument where the detector is located in close proximity to the instrument analysis window held against the sample. A portable EDXRF instrument was used to collect spectra from specimens containing plutonium-239 (a moderate alpha emitter) and americium-241 (a heavy alpha emitter). These specimens were then analyzed with a wavelength dispersive XRF (WDXRF) instrument to demonstrate the differences to which sample radiation-induced X-ray emission affects the detectors on these two types of XRF instruments.

  19. VLF emissions from ionospheric/magnetospheric plasma

    Indian Academy of Sciences (India)

    R P Patel; R P Singh

    2001-05-01

    VLF emissions such as hiss, chorus, oscillating tones, hiss-triggered chorus and whistler triggered emissions have been observed at low latitude Indian stations. In this paper we present dynamic spectra of these emissions and discuss their various observed features. It is argued that most of the emissions are generated during Doppler shifted cyclotron resonance interaction between the whistler mode wave and counter streaming energetic electrons. Resonance energy of the participating electron and interaction length are evaluated to explain the generation mechanism of some of these emissions observed at Indian stations.

  20. The long wavelength emission of interstellar PAHs: characterizing the spinning dust emission

    CERN Document Server

    Ysard, Nathalie

    2009-01-01

    The emission of cold dust grains at long wavelengths will soon be observed by the Planck and Herschel satellites and provide new constraints on the nature of interstellar dust. The microwave anomalous emission, proposed to be due to spinning PAHs, should help to better define these species. Moreover, understanding the fluctuations of the anomalous emission over the sky is crucial for CMB studies. We focus on the long wavelength emission of interstellar PAHs in their rovibrational and rotational transitions. The PAH emission spectrum from the IR to the microwave range is presented and compared to anomalous emission observations. To model their long wavelength emission, we treat PAHs as isolated systems and follow consistently their IR and rotational emissions. We consider several interstellar phases and discuss how the anomalous emission may constrain their size distribution. Our model of PAH emission accounts for the mid-IR spectra of the diffuse interstellar medium and of the Orion Bar. For lambda<3mm the...

  1. THEORETICAL SPECTRA OF TERRESTRIAL EXOPLANET SURFACES

    Energy Technology Data Exchange (ETDEWEB)

    Hu Renyu; Seager, Sara [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Ehlmann, Bethany L., E-mail: hury@mit.edu [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)

    2012-06-10

    We investigate spectra of airless rocky exoplanets with a theoretical framework that self-consistently treats reflection and thermal emission. We find that a silicate surface on an exoplanet is spectroscopically detectable via prominent Si-O features in the thermal emission bands of 7-13 {mu}m and 15-25 {mu}m. The variation of brightness temperature due to the silicate features can be up to 20 K for an airless Earth analog, and the silicate features are wide enough to be distinguished from atmospheric features with relatively high resolution spectra. The surface characterization thus provides a method to unambiguously identify a rocky exoplanet. Furthermore, identification of specific rocky surface types is possible with the planet's reflectance spectrum in near-infrared broad bands. A key parameter to observe is the difference between K-band and J-band geometric albedos (A{sub g}(K) - A{sub g}(J)): A{sub g}(K) - A{sub g}(J) > 0.2 indicates that more than half of the planet's surface has abundant mafic minerals, such as olivine and pyroxene, in other words primary crust from a magma ocean or high-temperature lavas; A{sub g}(K) - A{sub g}(J) < -0.09 indicates that more than half of the planet's surface is covered or partially covered by water ice or hydrated silicates, implying extant or past water on its surface. Also, surface water ice can be specifically distinguished by an H-band geometric albedo lower than the J-band geometric albedo. The surface features can be distinguished from possible atmospheric features with molecule identification of atmospheric species by transmission spectroscopy. We therefore propose that mid-infrared spectroscopy of exoplanets may detect rocky surfaces, and near-infrared spectrophotometry may identify ultramafic surfaces, hydrated surfaces, and water ice.

  2. NO2分子内能传递和弛豫过程的光声和荧光光谱探测%Investigation on Internal Energy Transfer and Relaxation Kinetics of NO2 by Photoacoustic and Fluorescence Emission Spectra

    Institute of Scientific and Technical Information of China (English)

    张贵银; 马金英; 靳一东

    2011-01-01

    With 532 nm laser as excitation source, the excitation and relaxation process of NO2 molecule was investigated by the technique of photoacoustic and fluorescence emission spectra. The results show that NO2 molecules will be pumped to the first excited electronic state by laser photon. When the sample pressure is lower, some of the excited molecules relax to the ground state by radiation process directly; the other parts are redistributed to a few of the excited rovibronic energy levels by the process of fast internal energy transfer. With the increase in the sample pressure, continual collisions dominate the relaxation process gradually. This makes the excited molecules to be redistributed to many excited rovibronic energy levels. Emission from these excited levels forms a continuous spectrum. Just then, the efficiency of fluorescence emission from laser excited level decreases and the fluorescence intensity on the long wavelength side increases. The intensity of PA signals increases also. These phenomena indicate that besides the relaxation process of radiation, there is a strong relaxation process of continual collision under the condition of higher sample pressure. It converts vibration energy of the excited molecules into translation one. This induces the increase in gas temperature and a sound wave is produced.%将荧光光谱和光声光谱两种互补的探测技术结合起来,从辐射和无辐射跃迁两个方面,分析了 532nm激光作用下,NO2分子的激发和弛豫过程.发现NO2分子在激光作用下,将跃迁至第一激发电子态.当样品气压较低时,受激NO2分子除辐射荧光外,可通过快速的内能转移过程实现在几个振转能级的再布居;随样品气压的升高,分子间碰撞加剧,受激NO2分子通过分子间的碰撞,实现在多个振转能级的再布居.激光布居能级的荧光辐射效率随样品气压的升高逐渐降低,而长波区域的荧光辐射及光声信号强度逐渐增强,说明在高

  3. Atomic and Molecular Aspects of Astronomical Spectra

    Science.gov (United States)

    Sochi, Taha

    2012-11-01

    In the first section we present the atomic part where a C2+ atomic target was prepared and used to generate theoretical data to investigate recombination lines arising from electron-ion collisions in thin plasma. R-matrix method was used to describe the C2+ plus electron system. Theoretical data concerning bound and autoionizing states were generated in the intermediate-coupling approximation. The data were used to generate dielectronic recombination data for C+ which include transition lines, oscillator strengths, radiative transition probabilities, emissivities and dielectronic recombination coefficients. The data were cast in a line list containing 6187 optically-allowed transitions which include many C II lines observed in astronomical spectra. This line list was used to analyze the spectra from a number of astronomical objects, mainly planetary nebulae, and identify their electron temperature. The electron temperature investigation was also extended to include free electron energy analysis to investigate the long-standing problem of discrepancy between the results of recombination and forbidden lines analysis and its possible connection to the electron distribution. In the second section we present the results of our molecular investigation; the generation of a comprehensive, calculated line list of frequencies and transition probabilities for H2D+. The line list contains over 22 million rotational-vibrational transitions occurring between more than 33 thousand energy levels and covers frequencies up to 18500 cm-1. About 15% of these levels are fully assigned with approximate rotational and vibrational quantum numbers. A temperature-dependent partition function and cooling function are presented. Temperature-dependent synthetic spectra for the temperatures T=100, 500, 1000 and 2000 K in the frequency range 0-10000 cm-1 were also generated and presented graphically.

  4. Emissions Trading

    NARCIS (Netherlands)

    Woerdman, Edwin; Backhaus, Juergen

    2014-01-01

    Emissions trading is a market-based instrument to achieve environmental targets in a cost-effective way by allowing legal entities to buy and sell emission rights. The current international dissemination and intended linking of emissions trading schemes underlines the growing relevance of this

  5. Emissions Trading

    NARCIS (Netherlands)

    Woerdman, Edwin; Backhaus, Juergen

    2014-01-01

    Emissions trading is a market-based instrument to achieve environmental targets in a cost-effective way by allowing legal entities to buy and sell emission rights. The current international dissemination and intended linking of emissions trading schemes underlines the growing relevance of this instr

  6. Study on Growth and Spectra Properties of Nd: GGG Crystal

    Institute of Scientific and Technical Information of China (English)

    Zeng Fanming; Sun Jing; Zhang Ying; Liu Jinghe

    2007-01-01

    The laser crystal Nd: GGG was grown by Cz method. The optimum processing parameter is that the pulling rate is 2~4mm·h-1, the rotation rate is 20~40 r·min-1 and the cooling rate is 20℃. The absorption and fluorescence spectra of Nd: GGG were measured. The main absorption peak of Nd: GGG is at 808 nm and the fluorescence emission peak is at 9430cm-1, corresponding to 4F3/2-4I11/2 emission band of Nd3+ ions.

  7. Scenario of temperature-related variation of phosphorescence spectra of ortho-bromobenzophenone crystal

    Science.gov (United States)

    Strzhemechny, M. A.; Stepanian, S. G.; Zloba, D. I.; Buravtseva, L. M.; Pyshkin, O. S.; Piryatinski, Yu. P.; Melnik, V. I.; Klishevich, G. V.; Adamowicz, L.

    2015-12-01

    Luminescence and other properties of solid 2-bromobenzophenone demonstrate features, which require special attention. We present results, which include DFT calculations, integrated and time-resolved phosphorescence spectra, and excitation spectra. The energies of the title molecule were calculated for the S0 , S1 , and T1 states. Nanosecond time-resolved phosphorescence spectra were measured at three temperature points at which the spectra undergo substantial changes. Joint analysis of energy surfaces and experimental evidence allowed reconstruction of the emission scenario that determines temperature-related variations of spectra. Upon excitation to state S1 the molecule converges very fast to T1 , emission from which can occur from the minima at 60° or at 180°. At low temperatures the molecule emits from the former, whereas at higher temperatures the molecule can overcome the barrier to emit from the lower minimum. The probability of excimer formation increases with increasing temperature.

  8. Emission Facilities - Air Emission Plants

    Data.gov (United States)

    NSGIC Education | GIS Inventory — Represents the Primary Facility type Air Emission Plant (AEP) point features. Air Emissions Plant is a DEP primary facility type related to the Air Quality Program....

  9. Emission Facilities - Air Emission Plants

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Represents the Primary Facility type Air Emission Plant (AEP) point features. Air Emissions Plant is a DEP primary facility type related to the Air Quality Program....

  10. Calculation of Vibrational Energy-Spectra of α-Helical Protein Molecules and Its Properties

    Institute of Scientific and Technical Information of China (English)

    PANG XiaoFeng; CHEN XiangRong

    2002-01-01

    The quantum vibrational energy-spectra of amide-Is in alpha-protein molecules are calculated by using the discretely nonlinear Schrodinger equation and physical parameters appropriate to the systems on the basis of theory of bio-energy transport. The numerical results for the energy-spectra are basically consistent with the experimental values obtained by the infrared absorption and Raman scattering and emission-spectra of infrared lights of person's hand-fingers. Utilizing the energy-spectra we explain the laser-Raman spectrum from metabolically active E. Coli. and give some features of the infrared absorption of the protein molecules.

  11. Emission inventory; Inventaire des emissions

    Energy Technology Data Exchange (ETDEWEB)

    Fontelle, J.P. [CITEPA, Centre Interprofessionnel Technique d`Etudes de la Pollution Atmospherique, 75 - Paris (France)

    1997-12-31

    Statistics on air pollutant (sulfur dioxide, nitrogen oxides and ammonium) emissions, acid equivalent emissions and their evolution since 1990 in the various countries of Europe and the USA, are presented. Emission data from the industrial, agricultural, transportation and power sectors are given, and comparisons are carried out between countries based on Gnp and population, pollution import/export fluxes and compliance to the previous emission reduction objectives

  12. The Photoluminescence Spectra of the Aeschynite Group Minerals

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Raman and photoluminescence spectra of the metamict and annealing recrystallization titanoaeschynite-(Nd) and nioboaeschynite-(Ce), found in Baiyunobo mineral deposit in China, were measured and discussed. The peaks or bands in the spectra of the metamic minerals are weak, broad and diffuse, but sharpen notably after heating. The results show that the distortion of the structure and disorder state of the elements exists in the minerals when natural crystalline minerals transformed into metamict minerals after a long period of self-irradiation structure damaging. And all bands in the photoluminescence spectra of the aeschynite group mineral stem from emission transitions of Nd3+, when 514.5nm laser is used as the excitation source.

  13. Photoluminescence spectra of TlInSe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Wakita, Kazuki; Araki, Yoshito; Asaba, Ryo [Department of Electrical, Electronic and Computer Engineering, Chiba Institute of Technology, 2-17-1 Tsudanuma, 275-0016 Narashino (Japan); Shim, YongGu [Department of Physics and Electronics, Osaka Prefecture University, 1-1 Gakuencho, 599-8531 Sakai (Japan); Mamedov, Nazim [Institute of Physics, National Academy of Sciences of Azerbaijan, H. Javid ave. 33, 1143 Baku (Azerbaijan)

    2012-12-15

    Photoluminescence spectra of TlInSe{sub 2} crystals with quasi one-dimensional structure have been investigated. The observed broad spectra have been found to result from overlapping of two peaks centered at 1.05 and 0.97 eV. Following the results of the examination of the excitation intensity dependence of the observed photoluminescence, the last peaks have been attributed to free-to-bound radiative transitions. The activation energy of donor or acceptor levels associated with these emissions has been tentatively evaluated. Furthermore, two sharp peaks located at 1.17 and 1.23 eV have been observed at 10 K in the excitation spectra of the observed photoluminescence (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. An atlas of ultraviolet spectra of star-forming galaxies

    Science.gov (United States)

    Kinney, A. L.; Bohlin, R. C.; Calzetti, D.; Panagia, N.; Wyse, Rosemary F. G.

    1993-01-01

    A systematic study is presented of the UV spectra of star-forming galaxies of different morphological type and activity class using a sample drawn from a uniformly reduced IUE data set. The spectra for a wide variety of galaxies, including normal spiral, LINER, starburst, blue compact, blue compact dwarf, and Seyfert 2 galaxies, are presented in the form of spectral energy distributions to demonstrate the overall characteristics according to morphology and activity class and in the form of absolute flux distributions to better show the absorption and emission features of individual objects. The data support the picture based on UV spectra of the Orbiting Astronomical Observatory and of the Astronautical Netherlands Satellite that spiral galaxies of later Hubble class have more flux at the shortest UV wavelengths than do spiral galaxies of earlier Hubble class.

  15. Qualitative interpretation of galaxy spectra

    CERN Document Server

    Almeida, J Sanchez; Terlevich, E; Fernandes, R Cid; Morales-Luis, A B

    2012-01-01

    We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis, and for gaining physical insight when interpreting the outputs provided by automated tools. Though the recipe is of general application, it was developed for understanding the nature of the Automatic Spectroscopic K-means based (ASK) template spectra. They resulted from the classification of all the galaxy spectra in the Sloan Digital Sky Survey data release 7 (SDSS-DR7), thus being a comprehensive representation of the galaxy spectra in the local universe. Using the recipe, we give a description of the properties of the gas and the stars that characterize the ASK classes, from those corresponding to passively evolving galaxies, to HII galaxies undergoing a galaxy-wide starburst. The qualitative analysis is found to be in excellent agreement with quantitative analyses of the same spectra. A number of byprodu...

  16. GASP: A general-purpose program for environmental alpha spectra

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, A.M.; Tome, F.V.; Vargas, M.J. (Dept. de Fisica, Univ. de Extremadura, Badajoz (Spain))

    1992-02-01

    A computer program to study general environmental alpha-particle emission spectra obtained by using semiconductor detectors is described. Each alpha-emitting nuclide is analysed following a method which is suited to its case. Low-energy tail and branching-ratio corrections are included so that the area corresponding to each nuclide in the spectrum is obtained separately. Calculations are not iterative, and so the program is economic in its use of computer time and memory. (orig.).

  17. Publicly Released Prompt Radiation Spectra Suitable for Nuclear Detonation Simulations

    Science.gov (United States)

    2017-03-01

    emission. During the Hiroshima and Nagasaki bombings, the prompt radiation contributed from 40%-70% of the free-in-air dose depending on distance from...intermediate- and low -yield thermonuclear weapons for initial radiation shielding calculations No Gritzner, et al. 1976 (EM-1, Low , Henre...Publicly Released Prompt Radiation Spectra Suitable for Nuclear Detonation Simulations DISTRIBUTION A. Approved for public release; distribution is

  18. Accelerated Fitting of Stellar Spectra

    CERN Document Server

    Ting, Yuan-Sen; Rix, Hans-Walter

    2016-01-01

    Stellar spectra are often modeled and fit by interpolating within a rectilinear grid of synthetic spectra to derive the stars' labels: stellar parameters and elemental abundances. However, the number of synthetic spectra needed for a rectilinear grid grows exponentially with the label space dimensions, precluding the simultaneous and self-consistent fitting of more than a few elemental abundances. Shortcuts such as fitting subsets of parameters separately can introduce unknown systematics and do not produce correct error covariances in the derived labels. In this paper we present a new approach -- CHAT (Convex Hull Adaptive Tessellation) -- which includes several new ideas for inexpensively generating a sufficient stellar synthetic library, using linear algebra and the concept of an adaptive, data-driven grid. A convex hull approximates the region where the data lie in the label space. A variety of tests with mock datasets demonstrate that CHAT can reduce the number of required synthetic model calculations by...

  19. Mutation spectra of complex environmental mixtures

    Energy Technology Data Exchange (ETDEWEB)

    DeMarini, D.M. [EPA, Research Triangle Park, NC (United States)

    1997-10-01

    Bioassay-directed chemical analysis of complex environmental mixtures has indicated that much of the genotoxic activity of mixtures is due to the presence of one or a few classes or chemicals within the mixture. We have extended this observation to the molecular level by using colony probe hybridization and PCR/DNA sequence analysis to determine the mutation spectra of {approximately}8,000 revertants induced by a variety of complex mixtures and their chemical fractions in TA100 and TA98 of Salmonella. For urban air, >80% of mutagenic activity was due to a base/neutral fraction that contained primarily PAHs. The mutation spectrum induced by unfractionated urban air was not significantly different from that produced by a model PAH, B(a)P. The mutation spectrum induced by organic extracts of chlorinated drinking water were similar to those produced by the chlorinated furanone MX, which accounted for {approximately}20% of the mutagenic activity of the samples. The base/neutral fraction of municipal waste incinerator emissions accounted for the primary class of mutations induced by the emissions, and a polar neutral fraction accounted for the secondary class of mutations induced by the emissions. The primary class of mutations induced by cigarette smoke condensate in TA100 (GC {yields} TA) is also the primary class of mutations in the p53 gene of lung tumors of cigarette smokers. These results confirm at the molecular level that the mutations induced by a complex mixture reflect the dominance of one or a few classes of chemicals within the mixture.

  20. QUALITATIVE INTERPRETATION OF GALAXY SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Almeida, J.; Morales-Luis, A. B. [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain); Terlevich, R.; Terlevich, E. [Instituto Nacional de Astrofisica, Optica y Electronica, Tonantzintla, Puebla (Mexico); Cid Fernandes, R., E-mail: jos@iac.es, E-mail: abml@iac.es, E-mail: rjt@ast.cam.ac.uk, E-mail: eterlevi@inaoep.mx, E-mail: cid@astro.ufsc.br [Departamento de Fisica-CFM, Universidade Federal de Santa Catarina, P.O. Box 476, 88040-900 Florianopolis, SC (Brazil)

    2012-09-10

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

  1. The Of emission lines near 4650 A

    Science.gov (United States)

    Underhill, A. B.; Gilroy, K. K.; Hill, G. M.

    1989-09-01

    Rectified, normalized, high S/N intensity tracings of nine Of stars were obtained from Reticon spectra in the 4550-4800-A region. The well-known relatively sharp Of emission lines are seen to stand on pedestals of broad weak emission somewhat like the broad emission lines from WR stars. It is suggested that cascades following dielectronic recombination may be an important process driving some lines of N III, C III, and C IV into the emission of Of stars, and that the sharp Of lines come from plasma that is stationary with respect to the star. The broad emission features show an extensive low-density wind from each star. The results imply that the detection of two, more or less equal, broad jumps in the rest spectra of galaxies at about 4640 and 4686 A is more indicative of Of stars than of WR stars.

  2. Evoked acoustic emission

    DEFF Research Database (Denmark)

    Elberling, C; Parbo, J; Johnsen, N J

    1985-01-01

    Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has onl...... reveals presence of a true emission from all ears tested. It is concluded that the cochlear echo can be recorded in normal-hearing newborns with an extremely low rate of type I errors.......Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has only...... a minor effect on the power spectra, i.e. the maximum jumps from one spectral peak to another. Experiments with deconvolution demonstrate that the emission generating system at least at a fixed intensity can be regarded as being linear and characterized by its impulse response which is similar...

  3. Classical Trajectories and Quantum Spectra

    Science.gov (United States)

    Mielnik, Bogdan; Reyes, Marco A.

    1996-01-01

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

  4. Missing levels in correlated spectra

    CERN Document Server

    Bohigas, O

    2004-01-01

    Complete spectroscopy (measurements of a complete sequence of consecutive levels) is often considered as a prerequisite to extract fluctuation properties of spectra. It is shown how this goal can be achieved even if only a fraction of levels are observed. The case of levels behaving as eigenvalues of random matrices, of current interest in nuclear physics, is worked out in detail.

  5. Squeezed States and Helmholtz Spectra

    CERN Document Server

    Francisco Delgado, C; Reyes, M A; Mielnik, Bogdan; Reyes, Marco A

    1997-01-01

    The 'classical interpretation' of the wave function psi(x) reveals an interesting operational aspect of the Helmholtz spectra. It is shown that the traditional Sturm-Liouville problem contains the simplest key to predict the squeezing effect for charged particle states.

  6. Universal Behavior in Dirac Spectra

    CERN Document Server

    Verbaarschot, J J M

    1997-01-01

    In these lectures we review recent results on universal fluctuations of QCD Dirac spectra and applications of Random Matrix Theory (RMT) to QCD. We review general properties of Dirac spectra and discuss the relation between chiral symmetry breaking and correlations of Dirac eigenvalues. In particular, we will focus on the microscopic spectral density density, i.e. the spectral density near zero virtuality on the scale of a typical level spacing. The relation with Leutwyler-Smilga sum-rules will be discussed. The success of applications of RMT to spectra of 'complex' systems leads us to the introduction of a chiral Random Matrix Theory (chRMT) with the global symmetries of the QCD partition function. Our central conjecture is that it decribes correlations of QCD Dirac spectra. We will review recent universality proofs supporting this conjecture. Lattice QCD results for the microscopic spectral density and for correlations in the bulk of the spectrum are shown to be in perfect agreement with chRMT. We close wit...

  7. Gallery of Planetary Nebula Spectra

    CERN Document Server

    Kwitter, K B; Kwitter, Karen B.; Henry, Richard B.C.

    2006-01-01

    We present the Gallery of Planetary Nebula Spectra now available at http://oitwilliams.edu/nebulae. The website offers high-quality, moderate resolution (~7-10 A FWHM) spectra of 128 Galactic planetary nebulae from 3600-9600 A, obtained by Kwitter, Henry, and colleagues with the Goldcam spectrograph at the KPNO 2.1-m or with the RC spectrograph at the CTIO 1.5-m. The master PN table contains atlas data and an image link. A selected object's spectrum is displayed in a zoomable window; line identification templates are provided. In addition to the spectra themselves, the website also contains a brief discussion of PNe as astronomical objects and as contributors to our understanding of stellar evolution. We envision that this website, which concentrates a large amount of data in one place, will be of interest to a variety of users: researchers might need to check the spectrum of a particular object of interest; the non-specialist astronomer might simply be interested in perusing such a collection of spectra; and...

  8. Vibrational spectra of ordered perovskites

    NARCIS (Netherlands)

    Corsmit, A.F.; Hoefdraad, H.E.; Blasse, G.

    1972-01-01

    The vibrational spectra of the molecular M6+O6 (M = Mo, Te, W) group in ordered perovskites of the type Ba2M2+M6+O6 are reported. These groups have symmetry Oh, whereas their site symmetry is also Oh. An assignment of the internal vibrations is presented.

  9. Spectra of sodium aluminate solutions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The UV spectra of sodium aluminate solutions were obtained in the sodium oxide concentration range from 59 to 409 g/L and the caustic ratio range from 1.5 to 4.0 to reveal the structure characteristics of them. It is found that a new peak appears at about 370 nm besides peaks at about 220 and 266 nm in all solutions. The new peak is strongly favored by high hydroxide concentration and high caustic ratio. And it only appears when the solutions are prepared by dissolving sodium hydroxide and aluminum hydroxide.In addition, the IR and Raman spectra of sodium aluminate solutions with high alkali concentration and high caustic ratio were measured, and the UV spectra of aqueous solutions of Al(H2O)63+ and AlF63- were measured as well. According to the crystal field theory in coordination chemistry as well as the above spectra characteristics, this new peak at about 370 nm is determined as the evidence of a new species of aluminate ion with a coordination number of 6.

  10. A flow cytometer for the measurement of Raman spectra.

    Science.gov (United States)

    Watson, Dakota A; Brown, Leif O; Gaskill, Daniel F; Naivar, Mark; Graves, Steven W; Doorn, Stephen K; Nolan, John P

    2008-02-01

    Multiparameter measurements in flow cytometry are limited by the broad emission spectra of fluorescent labels. By contrast, Raman spectra are notable for their narrow spectral features. To increase the multiparameter analysis capabilities of flow cytometry, we investigated the possibility of measuring Raman signals in a flow cytometry-based system. We constructed a Raman Spectral Flow Cytometer, substituting a spectrograph and CCD detector for the traditional mirrors, optical filters, and photomultiplier tubes. Excitation at 633 nm was provided by a HeNe laser, and forward-angle light scatter is used to trigger acquisition of complete spectra from individual particles. Microspheres were labeled with nanoparticle surface enhanced Raman scattering (SERS) tags and measured using the RSFC. Fluorescence and Raman spectra from labeled microspheres were acquired using the Raman Spectral Flow Cytometer. SERS spectral intensities were dependent on integration time, laser power, and detector pixel binning. Spectra from particles labeled with one each of four different SERS tags could be distinguished by either a virtual bandpass approach using commercial flow cytometry data analysis software or by principal component analysis. Raman flow cytometry opens up new possibilities for highly multiparameter and multiplexed measurements of cells and other particles using a simple optical design and a single detector and light source.

  11. Mid-infrared spectra of optically selected type 2 quasars

    CERN Document Server

    Zakamska, Nadia L; Strauss, Michael A; Krolik, Julian H

    2008-01-01

    Type 2 quasars are luminous Active Galactic Nuclei whose central engines are seen through large amounts of gas and dust. We present Spitzer spectra of twelve type 2 quasars selected on the basis of their optical emission line properties. Within this sample, we find a surprising diversity of spectra, from those that are featureless to those showing strong PAH emission, deep silicate absorption at 10 micron, hydrocarbon absorption, high-ionization emission lines and H_2 rotational emission lines. About half of the objects in the sample are likely Compton-thick, including the two with the deepest Si absorption. The median star-formation luminosity of the objects in our sample measured from the strength of the PAH features is 5x10^11 L_sun, much higher than for field galaxies or for any other AGN sample, but similar to other samples of type 2 quasars. This suggests an evolutionary link between obscured quasars and peak star formation activity in the host galaxy. Despite the high level of star formation, the bolom...

  12. Vanadium Oxide in the Spectra of Mira Variables

    Science.gov (United States)

    Castelaz, M. W.; Luttermoser, D. G.; Piontek, R. A.

    1999-05-01

    Over the last three years, we have made spectroscopic measurements of twenty Mira variable stars, as a function of phase, probing their stellar atmospheres and underlying pulsation mechanisms. Measurement of variations in TiO and VO with phase can be used to help determine whether these molecular species are produced in an extended region above the layers where Balmer line emission occurs or below this shocked region. Piontek & Luttermoser (1999 IAPPPC, submitted), produce synthetic spectra for three Mira variables, R Leo, V CVn, and R CVn as a function of phase. Comparison of their synthetic spectra to our observed spectra yield the fundamental astrophysical parameters of effective temperatures and surface gravities. Spectra are synthesized with LTE stellar stmospheres code ATLAS, using the 6.6--million Indiana University atomic and molecular line dataset. Piontek & Luttermoser point out that the IU dataset does not include vanadium oxide (VO). Thus, there is a noticeable difference between the synthetic spectra and observed near-IR spectra corresponding to the B-X bands of VO (Mahanti 1935, Proc. Phys. Soc., 47, 43; Keenan & Schroeder 1952,L. W., ApJ, 115, 82). In order to incorporate the VO bands in the synthetic spectra, we need to establish tables of wavenumbers, lowest energy levels, and oscillator strengths. Producing the tables is non-trivial. Laboratory measurements of wavenumbers are used in the Just-Overlapping Line Approximation (JOLA; Tsuji 1966, PASJ, 18, 127) to calculate oscillator strengths. The JOLA technique and preliminary results will be presented. MWC greatly appreciates support from the National Science Foundation grant AST-9500756. RAP acknowledges the Southeastern Association for Research in Astronomy 1998 Summer REU program supported by the National Science Foundation and thanks DGL for being his mentor.

  13. Curved Radio Spectra of Weak Cluster Shocks

    Science.gov (United States)

    Kang, Hyesung; Ryu, Dongsu

    2015-08-01

    In order to understand certain observed features of arc-like giant radio relics such as the rareness, uniform surface brightness, and curved integrated spectra, we explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud containing fossil relativistic electrons. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. Three types of fossil electron populations are considered: a delta-function like population with the shock injection momentum, a power-law distribution, and a power law with an exponential cutoff. The surface brightness profile of the radio-emitting postshock region and the volume-integrated radio spectrum are calculated and compared with observations. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed {u}{{s}}˜ 3× {10}3 {km} {{{s}}}-1 and sonic Mach number {M}{{s}}˜ 3. These shocks produce curved radio spectra that steepen gradually over (0.1-10){ν }{br} with a break frequency {ν }{br}˜ 1 GHz if the duration of electron acceleration is ˜60-80 Myr. However, the abrupt increase in the spectral index above ˜1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with {γ }{{e}}≳ {10}4.

  14. Phobos surface spectra mineralogical modeling

    Science.gov (United States)

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

    2014-04-01

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

  15. Eigenvectors of optimal color spectra.

    Science.gov (United States)

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

    2013-09-01

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

  16. Phonon spectra in quantum wires

    Directory of Open Access Journals (Sweden)

    Ilić Dušan

    2007-01-01

    Full Text Available Green's function method, adjusted to bound crystalline structures, was applied to obtain the phonon dispersion law in quantum wires. The condition of the existence of small mechanical atom movements defining phonon spectra can be found by solving the secular equation. This problem was presented graphically for different boundary parameters. The presence of boundaries, as well as the change of boundary parameters, leads to the appearance of new properties of the layered structure. The most important feature is that, beside the allowed energy zones (which are continuous as in the bulk structure, zones of forbidden states appear. Different values of the boundary parameters lead to the appearance of lower and upper energy gaps, or dispersion branches spreading out of the bulk energy zone. The spectra of phonons in corresponding unbound structures were correlated to those in bound structures.

  17. Electroluminescence and cathodoluminescence from polyethylene and polypropylene films: Spectra reconstruction from elementary components and underlying mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, B. [Université de Toulouse, UPS, INP, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse (France); Teyssedre, G.; Laurent, C. [Université de Toulouse, UPS, INP, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, LAPLACE, F-31062 Toulouse (France)

    2016-01-14

    The mechanisms of electroluminescence from large band gap polymers used as insulation in electric components are still under debate. It becomes important to unravel the underlying physics of the emission because of increasing thermo-electric stress and a possible relationship between electroluminescence and field withstand. We report herein on the cathodoluminescence spectra of polyethylene and polypropylene films as a way to uncover the nature of its contributions to electroluminescence emission. It is shown that spectra from the two materials are structured around four elementary components, each of them being associated with a specific process contributing to the overall emission with different weights depending on excitation conditions and on materials. The cathodoluminescence and electroluminescence spectra of each material are reconstructed from the four spectral components and their relative contribution are discussed. It is shown that electroluminescence from polyethylene and polypropylene has the same origin pointing towards generic mechanisms in both.

  18. Electroluminescence and cathodoluminescence from polyethylene and polypropylene films: Spectra reconstruction from elementary components and underlying mechanisms

    Science.gov (United States)

    Qiao, B.; Teyssedre, G.; Laurent, C.

    2016-01-01

    The mechanisms of electroluminescence from large band gap polymers used as insulation in electric components are still under debate. It becomes important to unravel the underlying physics of the emission because of increasing thermo-electric stress and a possible relationship between electroluminescence and field withstand. We report herein on the cathodoluminescence spectra of polyethylene and polypropylene films as a way to uncover the nature of its contributions to electroluminescence emission. It is shown that spectra from the two materials are structured around four elementary components, each of them being associated with a specific process contributing to the overall emission with different weights depending on excitation conditions and on materials. The cathodoluminescence and electroluminescence spectra of each material are reconstructed from the four spectral components and their relative contribution are discussed. It is shown that electroluminescence from polyethylene and polypropylene has the same origin pointing towards generic mechanisms in both.

  19. Modelling and Evaluation of Spectra in Beam Aided Spectroscopy

    Science.gov (United States)

    von Hellermann, M. G.; Delabie, E.; Jaspers, R.; Lotte, P.; Summers, H. P.

    2008-10-01

    The evaluation of active beam induced spectra requires advanced modelling of both active and passive features. Three types of line shapes are addressed in this paper: Thermal spectra representing Maxwellian distribution functions described by Gaussian-like line shapes, secondly broad-band fast ion spectra with energies well above local ion temperatures, and, finally, the narrow lines shapes of the equi-spaced Motion Stark multiplet (MSE) of excited neutral beam particles travelling through the magnetic field confining the plasma. In each case additional line shape broadening caused by Gaussian-like instrument functions is taken into account. Further broadening effects are induced by collision velocity dependent effective atomic rates where the observed spectral shape is the result of a convolution of emission rate function and velocity distribution function projected into the direction of observation. In the case of Beam Emission Spectroscopy which encompasses the Motional Stark features, line broadening is also caused by the finite angular spread of injected neutrals and secondly by a ripple in the acceleration voltage associated with high energy neutral beams.

  20. Understanding reconstructed Dante spectra using high resolution spectroscopy

    Science.gov (United States)

    May, M. J.; Weaver, J.; Widmann, K.; Kemp, G. E.; Thorn, D.; Colvin, J. D.; Schneider, M. B.; Moore, A.; Blue, B. E.

    2016-11-01

    The Dante is an 18 channel filtered diode array used at the National Ignition Facility (NIF) to measure the spectrally and temporally resolved radiation flux between 50 eV and 20 keV from various targets. The absolute flux is determined from the radiometric calibration of the x-ray diodes, filters, and mirrors and a reconstruction algorithm applied to the recorded voltages from each channel. The reconstructed spectra are very low resolution with features consistent with the instrument response and are not necessarily consistent with the spectral emission features from the plasma. Errors may exist between the reconstructed spectra and the actual emission features due to assumptions in the algorithm. Recently, a high resolution convex crystal spectrometer, VIRGIL, has been installed at NIF with the same line of sight as the Dante. Spectra from L-shell Ag and Xe have been recorded by both VIRGIL and Dante. Comparisons of these two spectroscopic measurements yield insights into the accuracy of the Dante reconstructions.

  1. Understanding reconstructed Dante spectra using high resolution spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    May, M. J., E-mail: may13@llnl.gov; Widmann, K.; Kemp, G. E.; Thorn, D.; Colvin, J. D.; Schneider, M. B.; Moore, A.; Blue, B. E. [L-170 Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94551 (United States); Weaver, J. [Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, DC 20375 (United States)

    2016-11-15

    The Dante is an 18 channel filtered diode array used at the National Ignition Facility (NIF) to measure the spectrally and temporally resolved radiation flux between 50 eV and 20 keV from various targets. The absolute flux is determined from the radiometric calibration of the x-ray diodes, filters, and mirrors and a reconstruction algorithm applied to the recorded voltages from each channel. The reconstructed spectra are very low resolution with features consistent with the instrument response and are not necessarily consistent with the spectral emission features from the plasma. Errors may exist between the reconstructed spectra and the actual emission features due to assumptions in the algorithm. Recently, a high resolution convex crystal spectrometer, VIRGIL, has been installed at NIF with the same line of sight as the Dante. Spectra from L-shell Ag and Xe have been recorded by both VIRGIL and Dante. Comparisons of these two spectroscopic measurements yield insights into the accuracy of the Dante reconstructions.

  2. Camera artifacts in IUE spectra

    Science.gov (United States)

    Bruegman, O. W.; Crenshaw, D. M.

    1994-01-01

    This study of emission line mimicking features in the IUE cameras has produced an atlas of artifiacts in high-dispersion images with an accompanying table of prominent artifacts and a table of prominent artifacts in the raw images along with a medium image of the sky background for each IUE camera.

  3. Near Infrared Spectra of the Orion Bar

    CERN Document Server

    Marconi, A; Natta, A; Walmsley, C M; Spazio, D A S; Firenze, U; Arcetri, O A

    1997-01-01

    We have used the LONGSP spectrometer on the 1.5-m TIRGO telescope to obtain long slit spectra in the J, H, and K wavelength bands towards two positions along the Orion bar. These data have been supplemented with images made using the ARNICA camera mounted on TIRGO as well as with an ESO NTT observation carried out by Dr A. Moorwood. We detect a variety of transitions of hydrogen, helium, OI, FeII, FeIII, and H_2 . From our molecular hydrogen data, we conclude that densities are moderate (3-6 10^4 cm^-3) in the layer responsible for the molecular hydrogen emission and give no evidence for the presence of dense neutral clumps. We also find that the molecular hydrogen bar is likely to be tilted by ~10 degrees relative to the line of sight. We discuss the relative merits of several models of the structure of the bar and conclude that it may be split into two structures separated by 0.2-0.3 parsec along the line of sight. It also seems likely to us that in both structures, density increases along a line perpendicu...

  4. CN and C2 vibrational spectra analysis in molecular LIBS of organic materials

    Science.gov (United States)

    Mousavi, S. J.; Hemati Farsani, M.; Darbani, S. M. R.; Mousaviazar, A.; Soltanolkotabi, M.; Eslami Majd, A.

    2016-05-01

    With the objective of investigation of the influence of molecular structure on CN violet and C2 Swan bands system spectra, plasma emissions from different organic materials, including polycyclic aromatic hydrocarbons, aromatic carboxylic acid, aliphatic carboxylic acid, amides and polymers, have been analyzed by laser-induced breakdown spectroscopy (LIBS) technique in air. To evaluate the influence of N2 and O2 molecules concentration on the CN and C2 molecular emissions, LIB spectra of four different samples have been recorded in air (approximately 80 % N2 and 20 % O2), nitrogen, oxygen and argon atmospheres. Experimental results indicate that the main reason for the absence of C2 emission in LIB spectra of samples which do not contain C-C bonds, when measurements were taken in air, is the presence of oxygen which could potentially deplete C2 emission rather than the absence of C-C bonds in their structure. Also, comparisons between experiment and theory spectra are made using a Nelder-Mead temperature program for CN and C2 bands with the ∆ν = 0 sequences from LIB spectra of different samples in various atmospheres. Furthermore, CN and C2 vibrational temperatures in Kelvin (K) are calculated from these spectral fittings. Both CN and C2 vibrational temperatures have highest values in argon atmosphere, and increasing the oxygen concentration in ambient atmosphere decreased those in most cases.

  5. Spectroscopy of unusual emission-line stars

    Science.gov (United States)

    Bopp, Bernard W.

    1988-01-01

    New spectroscopic observations are reported for ten stars that have been identified in the literature as having H-alpha emission with suspected F, G, or K spectral types. Three of the stars are shown to be BE stars, two are confirmed as early-type supergiants, three show composite (F or K + B) spectra, one is a 'post-T Tauri' star, and one is an ordinary F star without emission.

  6. Measured-predicted molecular spectra at band-line resolution

    Science.gov (United States)

    Freeman, G. N.; Akagi, T.; Barton, P. B. C.

    2016-10-01

    Early ERIM measurements of hot-through-cold gas (CO2, H2O, N2) emission-absorption spectra are replicated by modern line-band computations that incorporate independent fundamental line strength-frequency information. Close agreement is achieved for all cases by empirical adjustment of the line broadening function. Line spectra for CO2 and H2O computed at 0.001 cm-1 resolution were integrated to 3.2 and 14 cm-1 using a triangular slit function consistent with ERIM measurements for the 4.3 and 2.7 μm spectral regions. Band spectra computed at 0.1 cm-1 resolution give close agreement with spectra generated at higher resolution. The findings demonstrate a merged line-band model for nonuniform path radiance and transmittance based on the line-sum spectral cross section for each piecewise-uniform path segment. The band-and-line transmittance become equivalent at high spectral resolution.

  7. Analysing degeneracies in networks spectra

    CERN Document Server

    Marrec, Loïc

    2016-01-01

    Many real-world networks exhibit a high degeneracy at few eigenvalues. We show that a simple transformation of the network's adjacency matrix provides an understanding of? the origins of occurrence of high multiplicities in the networks spectra. We find that the eigenvectors associated with the degenerate eigenvalues shed light on the structures contributing to the degeneracy. Since these degeneracies are rarely observed in model graphs, we present results for various cancer networks. This approach gives an opportunity to search for structures contributing to degeneracy which might have an important role in a network.

  8. Rotational spectra and molecular structure

    CERN Document Server

    Wollrab, James E

    1967-01-01

    Physical Chemistry, A Series of Monographs: Rotational Spectra and Molecular Structure covers the energy levels and rotational transitions. This book is divided into nine chapters that evaluate the rigid asymmetric top molecules and the nuclear spin statistics for asymmetric tops. Some of the topics covered in the book are the asymmetric rotor functions; rotational transition intensities; classes of molecules; nuclear spin statistics for linear molecules and symmetric tops; and classical appearance of centrifugal and coriolis forces. Other chapters deal with the energy levels and effects of ce

  9. Infrared Spectra of Polycyclic Aromatic Hydrocarbons (PAHs)

    Science.gov (United States)

    Bauschlicher, Charles W., Jr.; Bakes, E. L. O.

    2000-01-01

    We have computed the synthetic infrared spectra of some polycyclic aromatic hydrocarbons containing up to 54 carbon atoms. The species studied include ovalene, circumcoronene, dicoronylene, and hexabenzocoronene. We report spectra for anions, neutrals, cations, and multiply charged cations.

  10. Calculation of delayed-neutron energy spectra in a QRPA-Hauser-Feshbach model

    Energy Technology Data Exchange (ETDEWEB)

    Kawano, Toshihiko [Los Alamos National Laboratory; Moller, Peter [Los Alamos National Laboratory; Wilson, William B [Los Alamos National Laboratory

    2008-01-01

    Theoretical {beta}-delayed-neutron spectra are calculated based on the Quasiparticle Random-Phase Approximation (QRPA) and the Hauser-Feshbach statistical model. Neutron emissions from an excited daughter nucleus after {beta} decay to the granddaughter residual are more accurately calculated than in previous evaluations, including all the microscopic nuclear structure information, such as a Gamow-Teller strength distribution and discrete states in the granddaughter. The calculated delayed-neutron spectra agree reasonably well with those evaluations in the ENDF decay library, which are based on experimental data. The model was adopted to generate the delayed-neutron spectra for all 271 precursors.

  11. A Survey and Analysis of Spitzer Infrared Spectrograph Spectra of T Tauri Stars in Taurus

    CERN Document Server

    Furlan, E; Calvet, N; D'Alessio, P; Franco-Hernandez, R; Forrest, W J; Watson, D M; Uchida, K I; Sargent, B; Green, J D; Keller, L D; Herter, T L

    2006-01-01

    We present mid-infrared spectra of T Tauri stars in the Taurus star-forming region obtained with the Spitzer Infrared Spectrograph (IRS). For the first time, the 5-36 micron spectra of a large sample of T Tauri stars belonging to the same star-forming region is studied, revealing details of the mid-infrared excess due to dust in circumstellar disks. We analyze common features and differences in the mid-IR spectra based on disk structure, dust grain properties, and the presence of companions. Our analysis encompasses spectral energy distributions from the optical to the far-infrared, a morphological sequence based on the IRS spectra, and spectral indices in IRS wave bands representative of continuum emission. By comparing the observed spectra to a grid of accretion disk models, we infer some basic disk properties for our sample of T Tauri stars, and find additional evidence for dust settling.

  12. A case study on the myth of emission from aliphatic amides

    Science.gov (United States)

    Singh, Avinash Kumar; Das, Sreyashi; Datta, Anindya

    2016-12-01

    For several decades, aliphatic amidic compounds have been believed to be emissive. We report that this contention is incorrect and that the anomalous emission from amides originates in fluorescent impurities generated during their synthesis. In order to make this point, we have synthesized fluorescent compounds and have compared the absorption spectra with excitation spectra.

  13. Electron Impact Induced VUV Emission from Argon

    Science.gov (United States)

    Young, J. A.; Malone, C. P.; Johnson, P. V.

    2011-10-01

    Emission intensity and spectra are important tools for diagnosing plasma properties such as electron temperature and neutral density. In order to properly interpret emissions from low-density plasmas, accurate cross sections are needed, particularly low energy electron-impact cross sections. Of interest are the cross sections for Argon, a common species used in industrial and lighting applications. In this paper, we present recent measurements of electron-impact induced VUV emissions from Ar using a magnetically collimated monoenergetic beam of electrons and a 0.2m spectrometer. Specifically, we present emission excitation functions for both Ar I(1048 Å) and Ar I(1066 Å) emissions. Similarities and differences between current results and previously published emission results will be discussed. Also discussed will be the relation to recent electron energy loss results.

  14. The Extragalactic Background Light and Absorption in Gamma Ray Spectra

    Science.gov (United States)

    Gilmore, Rudy C.

    2008-03-01

    Recent state-of-the-art semi-analytic models (SAMs) can now accurately model the history of galaxy formation and evolution. These SAMs utilize a 'forward evolution' approach and include all of the important processes for determining photon emission from galaxies, such as cooling and shock heating of gas, galaxy mergers, star formation and aging, supernova and AGN feedback, and the reprocessing of light by dust. I will be presenting our group's latest prediction of the extra-galactic background light based on this work and will discuss the implications for the attenuation of VHE gamma rays from distant sources due to pair-production. These results will be compared to recent limits placed on the EBL by observations of GeV and TeV blazar spectra by experiments such as H.E.S.S., MAGIC and VERITAS. The implications for reconstructing the intrinsic spectra of distant blazars will be addressed.

  15. Relativistic Effects on Reflection X-ray Spectra of AGN

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Khee-Gan; /University Coll. London; Fuerst, Steven V.; /KIPAC, Menlo Park; Brandwardi-Raymond, Graziella; Wu, Kinwah; Crowley, Oliver; /University Coll. London

    2007-01-05

    We have calculated the reflection component of the X-ray spectra of active galactic nuclei (AGN) and shown that they can be significantly modified by the relativistic motion of the accretion flow and various gravitational effects of the central black hole. The absorption edges in the reflection spectra suffer severe energy shifts and smearing. The degree of distortion depends on the system parameters, and the dependence is stronger for some parameters such as the inner radius of the accretion disk and the disk viewing inclination angles. The relativistic effects are significant and are observable. Improper treatment of the reflection component of the X-ray continuum in spectral fittings will give rise to spurious line-like features, which will mimic the fluorescent emission lines and mask the relativistic signatures of the lines.

  16. Fine Spectra of Symmetric Toeplitz Operators

    Directory of Open Access Journals (Sweden)

    Muhammed Altun

    2012-01-01

    Full Text Available The fine spectra of 2-banded and 3-banded infinite Toeplitz matrices were examined by several authors. The fine spectra of n-banded triangular Toeplitz matrices and tridiagonal symmetric matrices were computed in the following papers: Altun, “On the fine spectra of triangular toeplitz operators” (2011 and Altun, “Fine spectra of tridiagonal symmetric matrices” (2011. Here, we generalize those results to the (2+1-banded symmetric Toeplitz matrix operators for arbitrary positive integer .

  17. Duality properties between spectra and tilings

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Spectra and tilings play an important role in analysis and geometry respectively.The relations between spectra and tilings have bafied the mathematicians for a long time.Many conjectures,such as the Fuglede conjecture,are placed on the establishment of relations between spectra and tilings,although there are no desired results.In the present paper we derive some characteristic properties of spectra and tilings which highlight certain duality properties between them.

  18. The difference between laboratory and in-situ pixel-averaged emissivity: The effects on temperature-emissivity separation

    Science.gov (United States)

    Matsunaga, Tsuneo

    1993-01-01

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a Japanese future imaging sensor which has five channels in thermal infrared (TIR) region. To extract spectral emissivity information from ASTER and/or TIMS data, various temperature-emissivity (T-E) separation methods have been developed to date. Most of them require assumptions on surface emissivity, in which emissivity measured in a laboratory is often used instead of in-situ pixel-averaged emissivity. But if these two emissivities are different, accuracies of separated emissivity and surface temperature are reduced. In this study, the difference between laboratory and in-situ pixel-averaged emissivity and its effect on T-E separation are discussed. TIMS data of an area containing both rocks and vegetation were also processed to retrieve emissivity spectra using two T-E separation methods.

  19. VizieR Online Data Catalog: Spectra of blue compact galaxies (Kong+, 2002)

    Science.gov (United States)

    Kong, X.; Cheng, F. Z.; Weiss, A.; Charlot, S.

    2003-08-01

    This is the second paper in a series studying the star formation rates, stellar components, metallicities, and star formation histories and evolution of a sample of blue compact galaxies. We analyzed spectral properties of 97 blue compact galaxies, obtained with the Beijing Astronomical Observatory (China) 2.16m telescope, with spectral range 3580{AA}-7400{AA}. We classify the spectra according to their emission lines: 13 of the total 97 BCG sample are non-emission line galaxies (non-ELGs); 10 have AGN-like emission (AGNs), and 74 of them are star-forming galaxies (SFGs). Emission line fluxes and equivalent widths, continuum fluxes, the 4000A Balmer break index and equivalent widths of absorption lines are measured from the spectra. Please find more detail information in http://optik2.mtk.nao.ac.jp/~xkong/bcg/ (5 data files).

  20. Fast computation of morphological area pattern spectra

    NARCIS (Netherlands)

    Meijster, Arnold; Wilkinson, Michael H.F.

    2001-01-01

    An area based counterpart of the binary structural opening spectra is developed It is shown that these area opening and closing spectra can be computed using an adaptation of Tarjan's union-find algorithm These spectra provide rotation, translation, and scale invariant pattern vectors for texture

  1. Multiscale climate emulator of multimodal wave spectra: MUSCLE-spectra

    Science.gov (United States)

    Rueda, Ana; Hegermiller, Christie A.; Antolinez, Jose A. A.; Camus, Paula; Vitousek, Sean; Ruggiero, Peter; Barnard, Patrick L.; Erikson, Li H.; Tomás, Antonio; Mendez, Fernando J.

    2017-02-01

    Characterization of multimodal directional wave spectra is important for many offshore and coastal applications, such as marine forecasting, coastal hazard assessment, and design of offshore wave energy farms and coastal structures. However, the multivariate and multiscale nature of wave climate variability makes this complex problem tractable using computationally expensive numerical models. So far, the skill of statistical-downscaling model-based parametric (unimodal) wave conditions is limited in large ocean basins such as the Pacific. The recent availability of long-term directional spectral data from buoys and wave hindcast models allows for development of stochastic models that include multimodal sea-state parameters. This work introduces a statistical downscaling framework based on weather types to predict multimodal wave spectra (e.g., significant wave height, mean wave period, and mean wave direction from different storm systems, including sea and swells) from large-scale atmospheric pressure fields. For each weather type, variables of interest are modeled using the categorical distribution for the sea-state type, the Generalized Extreme Value (GEV) distribution for wave height and wave period, a multivariate Gaussian copula for the interdependence between variables, and a Markov chain model for the chronology of daily weather types. We apply the model to the southern California coast, where local seas and swells from both the Northern and Southern Hemispheres contribute to the multimodal wave spectrum. This work allows attribution of particular extreme multimodal wave events to specific atmospheric conditions, expanding knowledge of time-dependent, climate-driven offshore and coastal sea-state conditions that have a significant influence on local nearshore processes, coastal morphology, and flood hazards.

  2. The Optical Spectra of X-Shaped Radio Galaxies

    Science.gov (United States)

    2010-01-01

    Sky Survey ( SDSS ; Abazajian et al. 2009) but has only narrow emission lines in its spectrum (see Fig. A1), and J0245+1047, whose X- shaped radio...spectroscopically observed by the SDSS (Data Release 5; see Fig. A1). For another seven sources, namely, J0113+0106, J0115−0000, J0245+1047, J1309−0012...of this task to deblend the indi- vidual features. However, this procedure was not necessary in the case of the SDSS spectra, whose spectral resolution

  3. Configuration interaction in LTE spectra of heavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Bar-Shalom, A.; Oreg, J. [Negev Nuclear Research Centre, Beersheba (Israel); Goldstein, W. [Lawrence Livermore National Lab., CA (United States)

    1992-11-01

    We present a method for including the effects of configuration interaction (CI) between relativistic subconfigurations of an electron configuration in the calculation of emission and absorption spectra of plasmas in local thermodynamic equilibrium (LTE). Analytical expressions for the correction to the intensities, owing to Cl, of an unresolved transition array (UTA) and of a supertransition array (STA) are obtained when the correction is small compared to the spin-orbit splitting, bypassing the need to diagonalize energy matrices. These expressions serve as working formulas in the STA model and, in addition, reveal a priori the conditions under which CI effects are significant. Examples of the effect are presented.

  4. 基于1-(1′,3′-苯并噁唑-2′-甲基)苯并咪唑的钴(Ⅱ)配合物:晶体结构、弱相互作用和荧光发射光谱%Cobalt(H) Complex Based on 1-(1′ ,3′ -Benzoxazole-2′ -methyl)benzimidazole:Crystal Structure, Weak Interactions and Fluorescent Emission Spectra

    Institute of Scientific and Technical Information of China (English)

    吕世真; 李树娟; 王修光; 柳清湘

    2011-01-01

    配体1-(1′,3′-苯并恶唑-2′-甲基)苯并咪唑(L)是通过苯并咪唑与2-(氯甲基)-1,3-苯并恶唑烷基化制备而来.配体L与CoCl2·2H2O反应得到了配合物[CoCl2L2] (1).配合物1通过π-π堆积作用和C-H…Cl氢键形成了三维超分子框架结构.测定了L和1的荧光发射光谱.%The ligand 1-(1′,3′-benzoxazole-2′-methyl)benzimidazole (L) was prepared from benzimidazole by alkylation with 2-(chloromethyl)-1,3-benzoxazole.Reaction of ligand L with CoCl2 ·2H2O afforded a complex [CoCl2L2] (1).In complex 1,3D supramolecular frameworks were formed through π-π interactions and C-H…Cl hydrogen bonds.The fluorescence emission spectra of L and 1 are described.CCDC:843658.

  5. Scikit-spectra: Explorative Spectroscopy in Python

    Directory of Open Access Journals (Sweden)

    Adam Hughes

    2015-06-01

    Full Text Available Scikit-spectra is an intuitive framework for explorative spectroscopy in Python. Scikit-spectra leverages the Pandas library for powerful data processing to provide datastructures and an API designed for spectroscopy. Utilizing the new IPython Notebook widget system, scikit-spectra is headed towards a GUI when you want it, API when you need it approach to spectral analysis. As an application, analysis is presented of the surface-plasmon resonance shift in a solution of gold nanoparticles induced by proteins binding to the gold’s surface. Please refer to the scikit-spectra website for full documentation and support: http://hugadams.github.io/scikit-spectra/

  6. Analysis of multi-layer ERBS spectra

    Energy Technology Data Exchange (ETDEWEB)

    Marmitt, G.G. [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Rosa, L.F.S. [Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Nandi, S.K. [Electronic Materials Engineering Department, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2611 (Australia); Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh); Vos, M., E-mail: maarten.vos@anu.edu.au [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia)

    2015-07-15

    Highlights: • Electron Rutherford backscattering (ERBS) spectra are presented. • The spectra are fitted based on physical meaningful quantities. • Very consistent results are obtained for spectra taken under different conditions. • This establishes that ERBS can be used to measure film thicknesses. - Abstract: A systematic way of analysis of multi-layer electron Rutherford backscattering spectra is described. The approach uses fitting in terms of physical meaningful parameters. Simultaneous analysis then becomes possible for spectra taken at different incoming energies and measurement geometries. Examples are given to demonstrate the level of detail that can be resolved by this technique.

  7. Detailed Analysis of Early to Late-Time Spectra of Supernova 1993J

    CERN Document Server

    Matheson, T; Ho, L C; Barth, A J; Leonard, D C; Matheson, Thomas; Filippenko, Alexei V.; Ho, Luis C.; Barth, Aaron J.; Leonard, Douglas C.

    2000-01-01

    We present a detailed study of line structure in early to late-time spectra of Supernova (SN) 1993J. Spectra during the nebular phase, but within the first two years after explosion, exhibit small-scale structure in the emission lines of some species, notably oxygen and magnesium, showing that the ejecta of SN 1993J are clumpy. On the other hand, a lack of structure in emission lines of calcium implies that the source of calcium emission is uniformly distributed throughout the ejecta. These results are interpreted as evidence that oxygen emission originates in clumpy, newly synthesized material, while calcium emission arises from material pre-existing in the atmosphere of the progenitor. Spectra spanning the range 433-2454 days after the explosion show box-like profiles for the emission lines, clearly indicating circumstellar interaction in a roughly spherical shell. This is interpreted within the Chevalier & Fransson (1994) model for SNe interacting with mass lost during prior stellar winds. At very late...

  8. Similar features that appear both on the dynamic spectra of the Sun and Jupiter

    Science.gov (United States)

    Litvinenko, G.; Konovalenko, A.; Zakharenko, V.; Vinogradov, V.; Dorovsky, V.; Melnik, V.; Shaposhnikov, V.; Rucker, H. O.; Zarka, Ph.

    2013-09-01

    At present, the physical nature of the basic components of the solar sporadic radiation has been well studied and reliably identified non-equilibrium particle emission mechanisms responsible for their origin [1, 2, and references therein]. Jupiter decameter emission (DAM) represents an extraordinary astrophysical phenomenon which is characterized by an unusual complexity of the frequency-temporal structure of its dynamic spectra. It should be noted that since of its discovering many problems in the theory of the Jovian decameter emission have been successfully investigated and solved [3, and references therein]. Nevertheless, a great number of physical features of this phenomenon still remain unclear. It should be noted that the quasi-similar in shape features appear in the dynamic spectra both in the Sun and the Jovian radio emission. We hope that future research of the similar properties in the emission spectra of Jupiter and the Sun and analogy between the plasma processes in the solar corona and magnetosphere of Jupiter can allow also define the similar features in the radiation mechanisms of these cosmic objects. One of the promising approaches to investigating features of the Jovian DAM emission and the decameter solar radiation is application of novel experimental techniques with a further detailed analysis of the obtained data.

  9. Neutron and photon spectra in LINACs.

    Science.gov (United States)

    Vega-Carrillo, H R; Martínez-Ovalle, S A; Lallena, A M; Mercado, G A; Benites-Rengifo, J L

    2012-12-01

    A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10(-6) and 1 MeV. Neutron and the Bremsstrahlung spectra show the same features regardless of the linac voltage.

  10. Action spectra of zebrafish cone photoreceptors.

    Directory of Open Access Journals (Sweden)

    Duco Endeman

    Full Text Available Zebrafish is becoming an increasingly popular model in the field of visual neuroscience. Although the absorption spectra of its cone photopigments have been described, the cone action spectra were still unknown. In this study we report the action spectra of the four types of zebrafish cone photoreceptors, determined by measuring voltage responses upon light stimulation using whole cell patch clamp recordings. A generic template of photopigment absorption spectra was fit to the resulting action spectra in order to establish the maximum absorption wavelength, the A2-based photopigment contribution and the size of the β-wave of each cone-type. Although in general there is close correspondence between zebrafish cone action- and absorbance spectra, our data suggest that in the case of MWS- and LWS-cones there is appreciable contribution of A2-based photopigments and that the β-wave for these cones is smaller than expected based on the absorption spectra.

  11. Vacuum Rabi spectra of a single quantum emitter

    CERN Document Server

    Ota, Yasutomo; Kumagai, Naoto; Iwamoto, Satoshi; Arakawa, Yasuhiko

    2015-01-01

    We report the observation of the vacuum Rabi splitting of a single quantum emitter by measuring its direct spontaneous emission into free space. We used a semiconductor quantum dot inside a photonic crystal nanocavity, in conjunction with an appropriate cavity design and filtering with a polarizer and an aperture, enabling the extraction of the inherently-weak emitter's signal. The emitter's vacuum Rabi spectra exhibit clear differences to those measured by detecting the cavity photon leakage. Moreover, we observed an asymmetric vacuum Rabi spectrum induced by interference between the emitter and cavity detection channels. Our observations lay the groundwork for accessing various cavity quantum electrodynamics phenomena that manifest themselves only in the emitter's direct spontaneous emission.

  12. Graviton spectra in string cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Galluccio, Massimo [Osservatorio Astronomico di Roma (Roma-IT); Litterio, Marco [Istituto Astronomico dell' Universita (Roma-IT); Occhionero, Franco [Osservatorio Astronomico di Roma (Roma-IT)

    1996-08-01

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

  13. Graviton Spectra in String Cosmology

    CERN Document Server

    Galluccio, M; Occhionero, F; Galluccio, Massimo; Litterio, Marco; Occhionero, Franco

    1997-01-01

    We propose to uncover the signature of a stringy era in the primordial Universe by searching for a prominent peak in the relic graviton spectrum. This feature, which in our specific model terminates an $\\omega^3$ increase and initiates an $\\omega^{-7}$ decrease, is induced during the so far overlooked bounce of the scale factor between the collapsing deflationary era (or pre-Big Bang) and the expanding inflationary era (or post-Big Bang). We evaluate both analytically and numerically the frequency and the intensity of the peak and we show that they may likely fall in the realm of the new generation of interferometric detectors. The existence of a peak is at variance with ordinarily monotonic (either increasing or decreasing) graviton spectra of canonical cosmologies; its detection would therefore offer strong support to string cosmology.

  14. [Vibrational spectra of Corallium elatius].

    Science.gov (United States)

    Fan, Lu-wei; Zhang, Yan; Hu, Yang

    2013-09-01

    Corallium elatius, which has unique color distribution characteristic, is the most important species of Taiwan precious corals. EPMA, XRD, FTIR and Laser Raman detective methods were used to study the chemical, mineral composition and spectra characteristics of Corallium elatius. The result of EPMA, XRD and FTIR shows the high-Mg calcite mineral componentand the stable minor chemical constituents of the samples. Meanwhile, the cell parameter indicates the lattice distortion and the preferred orientation of calcite grain caused by organic matter. The red part of the samples shows a different Raman spectrum from that of the white part, located at 1517/1128 cm(-1) and 1296/1016 cm(-1). Raman scattering measurement reveals the relationship between the organic matter and color.

  15. Emissivity measurements of Mercury analogue materials from the Berlin Emissivity Database (BED)

    Science.gov (United States)

    Maturilli, A.; Helbert, J.; Moroz, L.

    To determine the planetary surfaces composition, remote sensing infrared spectroscopy is a suitable and powerful method of investigation. Past, present and future missions to bodies in the solar system include in their payload instruments measuring the emerging radiation in the infrared range. The MERTIS instrument, a TIR spectrometer combined with a radiometer, is part of the scientific payload of the ESA BepiColombo mission to Mercury, scheduled for 2013. The Berlin Emissivity Database (BED) is an emissivity spectral library of planetary analogue materials, essential for the interpretation of the measured data. Our unique database is focused on relatively fine-grained size separates, providing a realistic basis for interpretation of thermal emission spectra of Mercury and other planetary bodies. The BED spectral library currently contains emissivity spectra of plagioclase and potassium feldspars, low Ca and high Ca pyroxenes, olivine, elemental sulfur and a lunar highland soil sample measured in the wavelength range from 7 to 22 µm as a function of particle size. For each sample we measured the spectra of four particle size separates ranging from 0 to 250 µm. The device we used is built at DLR (Berlin) and is coupled to a Fourier transform infrared spectrometer (Bruker IFS 88), purged with dry air and equipped with a cooled detector (MCT). All spectra were acquired with a spectral resolution of 4 cm-1 . We present here the emissivity spectra of a basic set of analogue materials reflecting the current knowledge of the surface composition of Mercury. We are currently working to upgrade our emissivity facility: a new spectrometer (Bruker VERTEX 80v) and new detectors will allow us to measure the emissivity of samples in the wavelength range from 1 to 50 µm, even in a vacuum environment.

  16. Dissecting Galaxies: Spatial and Spectral Separation of Emission Excited by Star Formation and AGN Activity

    CERN Document Server

    Davies, Rebecca L; Kewley, Lisa J; Dopita, Michael A; Hampton, Elise J; Shastri, Prajval; Scharwachter, Julia; Sutherland, Ralph; Kharb, Preeti; Bhatt, Harish; Jin, Chichuan; Banfield, Julie; Zaw, Ingyin; James, Bethan; Juneau, Stephanie; Srivastava, Shweta

    2016-01-01

    The optical spectra of Seyfert galaxies are often dominated by emission lines excited by both star formation and AGN activity. Standard calibrations (such as for the star formation rate) are not applicable to such composite (mixed) spectra. In this paper, we describe how integral field data can be used to spectrally and spatially separate emission associated with star formation from emission associated with accretion onto an active galactic nucleus (AGN). We demonstrate our method using integral field data for two AGN host galaxies (NGC 5728 and NGC 7679) from the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). The spectra of NGC 5728 and NGC 7679 form clear sequences of AGN fraction on standard emission line ratio diagnostic diagrams. We show that the emission line luminosities of the majority (> 85 per cent) of spectra along each AGN fraction sequence can be reproduced by linear superpositions of the emission line luminosities of one AGN dominated spectrum and one star formation dominated...

  17. [Quantitative estimation of CaO content in surface rocks using hyperspectral thermal infrared emissivity].

    Science.gov (United States)

    Zhang, Li-Fu; Zhang, Xue-Wen; Huang, Zhao-Qiang; Yang, Hang; Zhang, Fei-Zhou

    2011-11-01

    The objective of the present paper is to study the quantitative relationship between the CaO content and the thermal infrared emissivity spectra. The surface spectral emissivity of 23 solid rocks samples were measured in the field and the first derivative of the spectral emissivity was also calculated. Multiple linear regression (MLR), principal component analysis (PCR) and partial least squares regression (PLSR) were modeled and the regression results were compared. The results show that there is a good relationship between CaO content and thermal emissivity spectra features; emissivities become lower when CaO content increases in the 10.3-13 mm region; the first derivative spectra have a better predictive ability compared to the original emissivity spectra.

  18. New insight on the interaction of self-activated and Mn-related emission centers in ZnS

    Science.gov (United States)

    Bacherikov, Yu Yu; Vorona, I.; Zhuk, A.; Gilchuk, A. V.; Korsunska, N.; Markevich, I.

    2017-02-01

    The photoluminescence (PL) and PL excitation (PLE) spectra of undoped and thermally doped with Mn ZnS single crystals are studied. In the PL spectra, the bands caused by Mn-related and self-activated (SA) emission centers were observed. A number of narrow peaks whose intensity enhanced with increasing Mn content were found in the PLE spectra of SA emission. The same peaks were present in the PLE spectra of the Mn-related emission band. Some of these peaks were previously observed in the absorption spectra and attributed to Mn2+ ions. The appearance of Mn-related peaks in the PLE spectra of SA emission is explained by excitation transfer from the Mn2+ ions to SA emission centers. The conditions required for this transfer and possible mechanisms of the process are discussed.

  19. Thermal emissivity of avian eggshells.

    Science.gov (United States)

    Björn, Lars Olof; Bengtson, Sven-Axel; Li, Shaoshan; Hecker, Christoph; Ullah, Saleem; Roos, Arne; Nilsson, Annica M

    2016-04-01

    The hypothesis has been tested that evolution has resulted in lower thermal emissivity of eggs of birds breeding openly in cold climates than of eggs of birds that nest under protective covering or in warmer climates. Directional thermal emissivity has been estimated from directional-hemispherical reflectance spectra. Due to several methodological difficulties the absolute emissivity is not accurately determined, but differences between species are obvious. Most notably, small waders of the genus Calidris, breeding in cold climates on the tundra, and in most cases with uniparental nest attendance, have low directional emissivity of their eggshells, about 0.92 when integration is carried out for wavelengths up to 16μm. Species belonging to Galloanserinae have the highest directional emissivity, about 0.96, of their eggs. No differences due to climate or breeding conditions were found within this group. Eggs of most other birds tested possess intermediate emissivity, but the values for Pica pica and Corvus corone cornix are as low as for Calidris. Large species-dependent differences in spectral reflectance were found at specific wavelengths. For instance, at 4.259μm the directional-hemispherical reflectance for galliforms range from 0.05 to 0.09, while for Fratercula arctica and Fulmarus glacialis it is about 0.3. The reflection peaks at 6.5 and 11.3μm due to calcite are differentially attenuated in different species. In conclusion, the hypothesis that evolution has resulted in lower thermal emissivity of bird eggs being exposed in cold climates is not supported by our results. The emissivity is not clearly related to nesting habits or climate, and it is unlikely that the small differences observed are ecologically important. The spectral differences between eggs that nevertheless exist should be taken into account when using infrared thermometers for estimating the surface temperature of avian eggs.

  20. Solvent effects on the absorption and emission spectra of novel (E)-4-((4-(heptyloxy)phenyl)diazenyl)benzyl (((9H-fluoren-9-yl)methoxy)carbonyl)-D-alaninate (Fmoc-al-az): Determination of dipole moment by experimental and theoretical study

    Science.gov (United States)

    Y, Tej Varma; Agarwal, Devesh S.; Sarmah, Amrit; Joshi, Lata; Sakhuja, Rajeev; Pant, Debi D.

    2017-02-01

    Amino acid appended azobenzene hybrid has been synthesized (Fmoc-al-az) and its electronic absorbance and fluorescence spectra were recorded at room temperature in a series of polar and non-polar solvents. The ground state and excited state dipole moments were calculated using solvatochromic shift method. A DFT based study was also performed using- Gaussian09 program package. We have observed that the absorption spectra don't show sensitive behavior to the change in the polarity of the solvent, whereas a bathochromic shift was observed in the fluorescence spectra as we moved from non-polar to polar solvents indicating a π→π* transition. It was observed that the dipole moment in the excited state is much higher than the ground state, due to the amino acid containing hydrogen bond acceptor (Osbnd Cdbnd O) and hydrogen bond donor (sbnd NH) in Fmoc-al-az increasing the reorientation tendency of the solvent molecule around the dye therefore enhancing the stabilization of the excited state which is attributed to the high polarity of the excited states. DFT level electronic structure calculations are also performed for a better molecular level understanding of the experimental observations. We obtained a good correlation between the theoretical studies and experimental results.

  1. Iron line profiles in Suzaku spectra of bare Seyfert galaxies

    CERN Document Server

    Patrick, A R; Porquet, D; Markowitz, A G; Lobban, A P; Terashima, Y

    2010-01-01

    We methodically model the broad-band Suzaku spectra of a small sample of six 'bare' Seyfert galaxies: Ark 120, Fairall 9, MCG-02-14-009, Mrk 335, NGC 7469 and SWIFT J2127.4+5654. The analysis of bare Seyferts allows a consistent and physical modelling of AGN due to a weak amount of any intrinsic warm absorption, removing the degeneracy between the spectral curvature due to warm absorption and the red-wing of the Fe K region. Through effective modelling of the broad-band spectrum and investigating the presence of narrow neutral or ionized emission lines and reflection from distant material, we obtain an accurate and detailed description of the Fe K line region using models such as laor, kerrdisk and kerrconv. Results suggest that ionized emission lines at 6.7 keV and 6.97 keV (particularly Fe XXVI) are relatively common and the inclusion of these lines can greatly affect the parameters obtained with relativistic models i.e. spin, emissivity, inner radius of emission and inclination. Moderately broad components...

  2. EMPCA and Cluster Analysis of Quasar Spectra: Sample Preparation and Validation

    Science.gov (United States)

    Wagner, Cassidy; Leighly, Karen; Macinnis, Francis; Marrs, Adam; Richards, Gordon T.

    2017-01-01

    All quasars are fundamentally similar, powered by accretion of matter onto a super massive black hole. However, patterns of differences can be identified through the emission lines. Quasar broad absorption lines have been postulated to be responsible for feedback in galaxy evolution. Principal component analysis (PCA) quantifies trends in emission lines of quasars that can be used to predict and reconstruct the underlying continuum in broad absorption line quasars.Richards et al. 2011 hypothesized that emission-line variance across the rest-UV spectrum is correlated with C IV blueshift and equivalent width. We fit their composite spectra, constructed based on these properties, to identify trends for the purpose of creating simulated spectra to test the weighted Expectation Maximization PCA (EMPCA; Bailey 2012) and cluster analysis method discussed in adjacent poster by Marrs et al.More than 800 SDSS spectra from Allen et al. 2011, with a redshift range of z = 2.2 - 2.3, were selected for analysis, particularly spectra with high signal to noise ratios, without broad absorption lines, and without numerous narrow absorption lines. Interstellar and intergalactic absorption lines add variance that contaminates the principal components. To remove these lines, we smoothed the spectra using a Fourier transform and a low-pass filter. We then used a line-finding and -removal program to remove or flag narrow absorption lines. From the principal components that resulted from the PCA analysis we were able to reconstruct the continua of a small sample of BAL QSOs.

  3. Characterization of the Effects of Precursor Mineralogy on Hematite Spectra: Application to Martian Hematite Mineralization

    Science.gov (United States)

    Glotch, Timothy D.; Morris, Richard V.; Sharp, Thomas G.; Christensen, Philip R.

    2003-01-01

    The Thermal Emission Spectrometer (TES) instrument aboard Mars Global Surveyor discovered several isolated deposits of gray, crystalline hematite in Sinus Meridiani, Aram Chaos, and Valles Marineris. A variety of formation mechanisms has been proposed for the martian hematite deposits, including aqueous and nonaqueous processes. Comparison of the average Sinus Meridiani hematite spectrum measured by TES to laboratory emissivity spectra for a variety of naturally occurring hematites shows small but potentially important differences. In particular, the emissivity minimum at 300 and 445/cm in the Sinus Meridiani (SM) spectrum is displaced 10-25/cm to lower frequencies compared to some natural hematite samples. In addition, these bands in the TES data are narrower than the broad bands seen in many natural hematite spectra. These differences may imply that the natural variability of hematite spectra has not been fully characterized, especially with respect to the reaction pathway (precursor mineralogy and temperature of hematite formation) and crystal morphology. Here, we describe the thermal infrared spectral characteristics of several series of synthetic hematite samples derived by direct precipitation, dehydroxylation of fine-grained goethite and the oxidation of magnetite. Several natural hematite sample spectra are also presented for comparison. Transmission electron microscopy (TEM) and Mossbauer spectral analyses of selected samples were performed in order to help determine the causes of the changes seen in the infrared spectra.

  4. Mid infrared emission spectroscopy of carbon plasma

    Science.gov (United States)

    Nemes, Laszlo; Brown, Ei Ei; Yang, Clayton S.-C.; Hommerich, Uwe

    2017-01-01

    Mid infrared time-resolved emission spectra were recorded from laser-induced carbon plasma. These spectra constitute the first study of carbon materials LIB spectroscopy in the mid infrared range. The carbon plasma was induced using a Q-switched Nd: YAG laser. The laser beam was focused to high purity graphite pellets mounted on a translation stage. Mid infrared emission from the plasma in an atmospheric pressure background gas was detected by a cooled HgCdTe detector in the range 4.4-11.6 μm, using long-pass filters. LIB spectra were taken in argon, helium and also in air. Despite a gate delay of 10 μs was used there were strong backgrounds in the spectra. Superimposed on this background broad and noisy emission bands were observed, the form and position of which depended somewhat on the ambient gas. The spectra were digitally smoothed and background corrected. In argon, for instance, strong bands were observed around 4.8, 6.0 and 7.5 μm. Using atomic spectral data by NIST it could be concluded that carbon, argon, helium and nitrogen lines from neutral and ionized atoms are very weak in this spectral region. The width of the infrared bands supports molecular origin. The infrared emission bands were thus compared to vibrational features of carbon molecules (excluding C2) of various sizes on the basis of previous carbon cluster infrared absorption and emission spectroscopic analyses in the literature and quantum chemical calculations. Some general considerations are given about the present results.

  5. Mid infrared emission spectroscopy of carbon plasma.

    Science.gov (United States)

    Nemes, Laszlo; Brown, Ei Ei; S-C Yang, Clayton; Hommerich, Uwe

    2017-01-05

    Mid infrared time-resolved emission spectra were recorded from laser-induced carbon plasma. These spectra constitute the first study of carbon materials LIB spectroscopy in the mid infrared range. The carbon plasma was induced using a Q-switched Nd: YAG laser. The laser beam was focused to high purity graphite pellets mounted on a translation stage. Mid infrared emission from the plasma in an atmospheric pressure background gas was detected by a cooled HgCdTe detector in the range 4.4-11.6μm, using long-pass filters. LIB spectra were taken in argon, helium and also in air. Despite a gate delay of 10μs was used there were strong backgrounds in the spectra. Superimposed on this background broad and noisy emission bands were observed, the form and position of which depended somewhat on the ambient gas. The spectra were digitally smoothed and background corrected. In argon, for instance, strong bands were observed around 4.8, 6.0 and 7.5μm. Using atomic spectral data by NIST it could be concluded that carbon, argon, helium and nitrogen lines from neutral and ionized atoms are very weak in this spectral region. The width of the infrared bands supports molecular origin. The infrared emission bands were thus compared to vibrational features of carbon molecules (excluding C2) of various sizes on the basis of previous carbon cluster infrared absorption and emission spectroscopic analyses in the literature and quantum chemical calculations. Some general considerations are given about the present results.

  6. MCNP modelling of scintillation-detector gamma-ray spectra from natural radionuclides

    NARCIS (Netherlands)

    Hendriks, Peter; Maucec, M; de Meijer, RJ

    2002-01-01

    gamma-ray spectra of natural radionuclides are simulated for a BGO detector in a borehole geometry using the Monte Carlo code MCNP. All gamma-ray emissions of the decay of K-40 and the series of Th-232 and U-238 are used to describe the source. A procedure is proposed which excludes the time-consumi

  7. The NASA Ames Polycyclic Aromatic Hydrocarbon Infrared Spectroscopic Database : The Computed Spectra

    NARCIS (Netherlands)

    Bauschlicher, C. W.; Boersma, C.; Ricca, A.; Mattioda, A. L.; Cami, J.; Peeters, E.; de Armas, F. Sanchez; Saborido, G. Puerta; Hudgins, D. M.; Allamandola, L. J.

    2010-01-01

    The astronomical emission features, formerly known as the unidentified infrared bands, are now commonly ascribed to polycyclic aromatic hydrocarbons (PAHs). The laboratory experiments and computational modeling done at the NASA Ames Research Center to create a collection of PAH IR spectra relevant t

  8. The NASA Ames Polycyclic Aromatic Hydrocarbon Infrared Spectroscopic Database: The Computed Spectra

    NARCIS (Netherlands)

    Bauschlicher, C. W.; Boersma, C.; Ricca, A.; Mattioda, A. L.; Cami, J.; Peeters, E.; Sánchez de Armas, F.; Puerta Saborido, G.; Hudgins, D. M.; Allamandola, L. J.

    2010-01-01

    The astronomical emission features, formerly known as the unidentified infrared bands, are now commonly ascribed to polycyclic aromatic hydrocarbons (PAHs). The laboratory experiments and computational modeling done at the NASA Ames Research Center to create a collection of PAH IR spectra relevant t

  9. The NASA Ames Polycyclic Aromatic Hydrocarbon Infrared Spectroscopic Database : The Computed Spectra

    NARCIS (Netherlands)

    Bauschlicher, C. W.; Boersma, C.; Ricca, A.; Mattioda, A. L.; Cami, J.; Peeters, E.; de Armas, F. Sanchez; Saborido, G. Puerta; Hudgins, D. M.; Allamandola, L. J.

    The astronomical emission features, formerly known as the unidentified infrared bands, are now commonly ascribed to polycyclic aromatic hydrocarbons (PAHs). The laboratory experiments and computational modeling done at the NASA Ames Research Center to create a collection of PAH IR spectra relevant

  10. The NASA Ames Polycyclic Aromatic Hydrocarbon Infrared Spectroscopic Database: The Computed Spectra

    NARCIS (Netherlands)

    Bauschlicher, C. W.; Boersma, C.; Ricca, A.; Mattioda, A. L.; Cami, J.; Peeters, E.; Sánchez de Armas, F.; Puerta Saborido, G.; Hudgins, D. M.; Allamandola, L. J.

    2010-01-01

    The astronomical emission features, formerly known as the unidentified infrared bands, are now commonly ascribed to polycyclic aromatic hydrocarbons (PAHs). The laboratory experiments and computational modeling done at the NASA Ames Research Center to create a collection of PAH IR spectra relevant t

  11. Spectroscopic analysis of time-resolved emission from detonating thin film explosive samples

    Science.gov (United States)

    Kay, Jeffrey J.; Wixom, Ryan R.; Jilek, Brook A.; Knepper, Robert; Tappan, Alexander S.; Damm, David L.

    2017-01-01

    We report a series of time-resolved spectroscopic measurements that aim to characterize the reactions that occur during shock initiation of high explosives. The experiments employ time- and wavelength-resolved emission spectroscopy to analyze light emitted from detonating thin explosive films. This paper presents analysis of optical emission spectra from hexanitrostilbene (HNS) and pentaerythritol tetranitrate (PETN) thin film samples. Both vibrationally resolved and broadband emission features are observed in the spectra and area as electronic transitions of intermediate species.

  12. Tritium diagnostics by Balmer-alpha emission

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, C.H.; Ramsey, A.T.; Johnson, D.W.; Diesso, M.

    1993-02-01

    Spectral line emission from tritium in a plasma may be distinguished from deuterium emission by a small isotope shift. A diagnostic system to measure tritium Balmer-alpha emission from the plasma edge has been installed on TFTR. This system has been used in deuterium plasmas, and the deuterium alpha line profile used as a basis to predict the spectrum at differing tritium concentrations in future D-T runs. The tritium and deuterium lines are partially blended, however, analysis of the predicted D-T spectra by a line fitting program produced estimates of the tritium density that closely matched those input to the spectra, providing confidence that the tritium density can be reliably measured. The spectrum maps the tritium velocity distribution at the plasma edge and will be important for studies of tritium edge physics.

  13. Spatially-resolved spectra of the accretion disc of the novalike UU Aquarii

    CERN Document Server

    Baptista, R; Steiner, J E; Horne, K; Baptista, Raymundo; Horne, Keith

    2000-01-01

    Time-resolved spectroscopy of the novalike variable UU Aquarii is analyzedwith eclipse mapping techniques to produce spatially resolved spectra of itsaccretion disc and gas stream as a function of distance from disc centre in therange 3600-6900 \\AA. The spatially-resolved spectra show that the continuumemission becomes progressively fainter and redder for increasing disc radius --reflecting the radial temperature gradient -- and reveal that the HI and HeIlines appear as deep, narrow absorption features in the inner disc regionstransitioning to emission with P Cygni profiles for intermediate and large discradii. The spectrum of the uneclipsed component has strong HI and HeI emissionlines plus a Balmer jump in emission and is explained as optically thinemission from a vertically extended disc chromosphere + wind. Most of the lineemission probably arises from the wind. The spatially-resolved spectra alsosuggest the existence of gas stream ``disk-skimming'' overflow in UU Aqr, whichcan be seen down to R \\simeq 0....

  14. Fluorescence line-narrowing spectra of Zn-cytochrome c. Temperature dependence

    Science.gov (United States)

    Koloczek, Henryk; Fidy, Judit; Vanderkooi, Jane M.

    1987-10-01

    Fluorescence site selection spectra of Zn-substituted cytochrome c and Zn-mesoporphyrin were measured as a function of excitation energy and temperature within 5-60 K. The emission energies determined for Zn-cytochrome c were comparable with those of Zn-mesoporphyrin and mesoporphyrin in polar glassy matrices and with resonance Raman spectra of heme proteins. In the site selection spectra of both Zn-cytochrome c and Zn-mesoporphyrin in polar organic glass an increase in the intensity of zero phonon emission lines was observed with an increase of temperature between 5 and 30 K. The irregular spectral changes were interpreted on the basis of the temperature dependence of the linewidth as well as possible hole-burning phenomena.

  15. Measurement of CIB power spectra over large sky areas from Planck HFI maps

    CERN Document Server

    Ying, Suet; Challinor, Anthony; Efstathiou, Geroge; Lagache, Guilaine

    2016-01-01

    We present new measurements of the power spectra of the cosmic infrared background (CIB) anisotropies using the Planck 2015 full-mission HFI data at 353, 545, and 857 GHz over 20000 square degrees. We use techniques similar to those applied for the cosmological analysis of Planck, subtracting dust emission at the power spectrum level. Our analysis gives stable solutions for the CIB power spectra with increasing sky coverage up to about 50% of the sky. These spectra agree well with Hi cleaned spectra from Planck measured on much smaller areas of sky with low Galactic dust emission. At 545 and 857 GHz our CIB spectra agree well with those measured from Herschel data. We find that the CIB spectra at l > 500 are well fitted by a power-law model for the clustered CIB, with a shallow index {\\gamma}^cib = 0.53\\pm0.02. This is consistent with the CIB results at 217 GHz from the cosmological parameter analysis of Planck. We show that a linear combination of the 545 and 857 GHz Planck maps is dominated by CIB fluctuati...

  16. Measurement of CIB power spectra over large sky areas from Planck HFI maps

    Science.gov (United States)

    Mak, Daisy Suet Ying; Challinor, Anthony; Efstathiou, George; Lagache, Guilaine

    2017-04-01

    We present new measurements of the power spectra of the cosmic infrared background (CIB) anisotropies using the Planck 2015 full-mission High frequency instrument data at 353, 545 and 857 GHz over 20 000 deg2. We use techniques similar to those applied for the cosmological analysis of Planck, subtracting dust emission at the power spectrum level. Our analysis gives stable solutions for the CIB power spectra with increasing sky coverage up to about 50 per cent of the sky. These spectra agree well with H I-cleaned spectra from Planck measured on much smaller areas of sky with low Galactic dust emission. At 545 and 857 GHz, our CIB spectra agree well with those measured from Herschel data. We find that the CIB spectra at ℓ ≳ 500 are well fitted by a power-law model for the clustered CIB, with a shallow index γcib = 0.53 ± 0.02. This is consistent with the CIB results at 217 GHz from the cosmological parameter analysis of Planck. We show that a linear combination of the 545 and 857 GHz Planck maps is dominated by the CIB fluctuations at multipoles ℓ ≳ 300.

  17. Skyglow effects in UV and visible spectra: Radiative fluxes

    Science.gov (United States)

    Kocifaj, Miroslav; Solano Lamphar, Hector Antonio

    2013-09-01

    Several studies have tried to understand the mechanisms and effects of radiative transfer under different night-sky conditions. However, most of these studies are limited to the various effects of visible spectra. Nevertheless, the invisible parts of the electromagnetic spectrum can pose a more profound threat to nature. One visible threat is from what is popularly termed skyglow. Such skyglow is caused by injudiciously situated or designed artificial night lighting systems which degrade desired sky viewing. Therefore, since lamp emissions are not limited to visible electromagnetic spectra, it is necessary to consider the complete spectrum of such lamps in order to understand the physical behaviour of diffuse radiation at terrain level. In this paper, the downward diffuse radiative flux is computed in a two-stream approximation and obtained ultraviolet spectral radiative fluxes are inter-related with luminous fluxes. Such a method then permits an estimate of ultraviolet radiation if the traditionally measured illuminance on a horizontal plane is available. The utility of such a comparison of two spectral bands is shown, using the different lamp types employed in street lighting. The data demonstrate that it is insufficient to specify lamp type and its visible flux production independently of each other. Also the UV emissions have to be treated by modellers and environmental scientists because some light sources can be fairly important pollutants in the near ultraviolet. Such light sources can affect both the living organisms and ambient environment.

  18. Complex structure of spatially resolved high-order-harmonic spectra

    Science.gov (United States)

    Catoire, F.; Ferré, A.; Hort, O.; Dubrouil, A.; Quintard, L.; Descamps, D.; Petit, S.; Burgy, F.; Mével, E.; Mairesse, Y.; Constant, E.

    2016-12-01

    We investigate the spatiospectral coupling appearing in the spatially resolved high-order-harmonic spectra generated in gases. When ionization is weak, harmonic generation in the far field often exhibits rings surrounding a central spot centered on each odd harmonics in the spatiospectral domain. The nature of these structures is debated. They could stem from interferences between the emission of short and long trajectories, or could be the signature of the temporal and spatial dependence of the longitudinal phase matching of long trajectories (Maker fringes). We conducted spectrally and spatially resolved measurements of the harmonic spectra as a function of pressure, intensity, and ellipticity. In addition, we performed calculations where only a single emission plane is included (i.e., omitting deliberately the longitudinal phase matching), reproducing the features experimentally observed. This study has been completed by the spatiospectral coupling when strong ionization occurs leading to complex patterns which have been compared to calculations using the same model and also show good agreement. We conclude that many spatiospectral structures of the harmonic spectrum can be interpreted in terms of spatial and temporal transverse coherence of the emitting medium without resorting to longitudinal phase matching or quantum phase interference between short and long trajectories.

  19. Characterizing the infrared spectra of small, neutral, fully dehydrogenated PAHs

    CERN Document Server

    Mackie, C J; Bauschlicher, C W; Cami, J

    2014-01-01

    We present the results of a computational study to investigate the infrared spectroscopic properties of a large number of polycyclic aromatic hydrocarbon (PAH) molecules and their fully dehydrogenated counterparts. We constructed a database of fully optimized geometries for PAHs that is complete for eight or fewer fused benzene rings, thus containing 1550 PAHs and 805 fully dehydrogenated aromatics. A large fraction of the species in our database have clearly non-planar or curved geometries. For each species, we determined the frequencies and intensities of their normal modes using density functional theory calculations. Whereas most PAH spectra are fairly similar, the spectra of fully dehydrogenated aromatics are much more diverse. Nevertheless, these fully dehydrogenated species show characteristic emission features at 5.2$\\mu$m, 5.5$\\mu$m and 10.6$\\mu$m; at longer wavelengths, there is a forest of emission features in the 16--30$\\mu$m range that appears as a structured continuum, but with a clear peak cent...

  20. The Spitzer Atlas of Stellar Spectra

    CERN Document Server

    Ardila, David R; Makowiecki, Wojciech; Stauffer, John; Song, Inseok; Rho, Jeonghee; Fajardo-Acosta, Sergio; Hoard, D W; Wachter, Stefanie

    2010-01-01

    We present the Spitzer Atlas of Stellar Spectra (SASS), which includes 159 stellar spectra (5 to 32 mic; R~100) taken with the Infrared Spectrograph on the Spitzer Space Telescope. This Atlas gathers representative spectra of a broad section of the Hertzsprung-Russell diagram, intended to serve as a general stellar spectral reference in the mid-infrared. It includes stars from all luminosity classes, as well as Wolf-Rayet (WR) objects. Furthermore, it includes some objects of intrinsic interest, like blue stragglers and certain pulsating variables. All the spectra have been uniformly reduced, and all are available online. For dwarfs and giants, the spectra of early-type objects are relatively featureless, dominated by Hydrogen lines around A spectral types. Besides these, the most noticeable photospheric features correspond to water vapor and silicon monoxide in late-type objects and methane and ammonia features at the latest spectral types. Most supergiant spectra in the Atlas present evidence of circumstell...

  1. Reflectance spectra of subarctic lichens

    Science.gov (United States)

    Petzold, Donald E.; Goward, Samuel N.

    1988-01-01

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

  2. Interpretation of Nitroindolinospirobenzothiopyran Vibrational Spectra

    Science.gov (United States)

    Gladkov, L. L.; Khamchukov, Yu. D.; Lyubimov, A. V.

    2016-05-01

    The structures of four possible stereoisomers of the closed form of photochromic nitroindolinospirobenzothiopyran (NISTP) {1',3'-dihydro-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzothiopyran-2,2'-(2H)-indoline]} were determined by the DFT method. The geometry of the most stable isomer was defined. Nitro-substitution changes mainly the lengths of bonds formed by S and N with spiro-atom Cs. According to the calculations, the CsS bond changes most and lengthens by 0.019 Å. It is shown that the S atom has large displacement amplitudes in normal modes assigned to Raman lines at 230, 285, 360, and 575 cm-1 and weak IR bands at 467 and 577 cm-1. Oscillations involving the nitro group are very active in Raman and IR spectra. Their frequencies are slightly lower than similar frequencies of nitrobenzene and nitroindolinospirobenzopyran, indicating a higher degree of vibrational coupling of the NO2 group with the NISTP molecular skeleton.

  3. Functional Regression for Quasar Spectra

    CERN Document Server

    Ciollaro, Mattia; Freeman, Peter; Genovese, Christopher; Lei, Jing; O'Connell, Ross; Wasserman, Larry

    2014-01-01

    The Lyman-alpha forest is a portion of the observed light spectrum of distant galactic nuclei which allows us to probe remote regions of the Universe that are otherwise inaccessible. The observed Lyman-alpha forest of a quasar light spectrum can be modeled as a noisy realization of a smooth curve that is affected by a `damping effect' which occurs whenever the light emitted by the quasar travels through regions of the Universe with higher matter concentration. To decode the information conveyed by the Lyman-alpha forest about the matter distribution, we must be able to separate the smooth `continuum' from the noise and the contribution of the damping effect in the quasar light spectra. To predict the continuum in the Lyman-alpha forest, we use a nonparametric functional regression model in which both the response and the predictor variable (the smooth part of the damping-free portion of the spectrum) are function-valued random variables. We demonstrate that the proposed method accurately predicts the unobserv...

  4. On non-forking spectra

    CERN Document Server

    Chernikov, Artem; Shelah, Saharon

    2012-01-01

    Non-forking is one of the most important notions in modern model theory capturing the idea of a generic extension of a type (which is a far-reaching generalization of the concept of a generic point of a variety). To a countable first-order theory we associate its non-forking spectrum - a function of two cardinals kappa and lambda giving the supremum of the possible number of types over a model of size lambda that do not fork over a sub-model of size kappa. This is a natural generalization of the stability function of a theory. We make progress towards classifying the non-forking spectra. On the one hand, we show that the possible values a non-forking spectrum may take are quite limited. On the other hand, we develop a general technique for constructing theories with a prescribed non-forking spectrum, thus giving a number of examples. In particular, we answer negatively a question of Adler whether NIP is equivalent to bounded non-forking. In addition, we answer a question of Keisler regarding the number of cut...

  5. Electronic Spectra of Chevreul's Salts

    Directory of Open Access Journals (Sweden)

    Silva Luciana A. da

    2002-01-01

    Full Text Available The isomorphic series of double sulfites with empirical formula Cu2SO3.MSO3.2H 2O (where M is Cu, Fe, Mn, or Cd have been prepared from the Cu(II replacement by transition metal ions such as Mn(II, Fe(II and Cd(II ions in Chevreul's salt, Cu2SO3.CuSO3.2H 2O. As a consequence, the isomorphic species present distinct colors. Molecular modeling calculations were carried out for the dimeric [CuI2(SO3 2(SO32]6- center. The electronic spectra of the Chevreul's salt consist of a charge-transfer band around 425 nm associated with the [CuI2(SO3 2(SO32]6- chromophore and two ligand field transitions at 785 and 1000 nm involving the Jahn-Teller splitting of the Cu(II levels. An additional intervalence-transfer band, responsible for its characteristic red color, can be found at 500 nm. The replacement of the Cu(II ions for Fe(II, Mn(II and Cd(II does not eliminate the absorption band at 425 nm, supporting its assignment as a charge-transfer transition centered on the Cu(I sites; while the original band at 500 nm disappears, in agreement with its intervalence transfer nature.

  6. Spitzer IRAC Images and Sample Spectra of Cassiopeia A's Explosion

    CERN Document Server

    Ennis, J A; Reach, W T; Smith, J D; Rho, J; Delaney, T A; Gomez, H L; Kozasa, T

    2006-01-01

    We present Spitzer IRAC images, along with representative 5.27 to 38.5 micron IRS spectra of the Cassiopeia A supernova remnant. We find that various IRAC channels are each most sensitive to a different spectral and physical component. Channel 1 (3.6 micron) matches radio synchrotron images. Where Channel 1 is strong with respect to the other channels, the longer-wavelength spectra show a broad continuum gently peaking around 26 micron, with weak or no lines. We suggest that this is due to un-enriched progenitor circumstellar dust behind the outer shock, processed by shock photons and electrons. Where Channel 4 (8 micron) is bright relative to the other IRAC channels, the long-wavelength spectra show a strong, 2-3 micron-wide peak at 21 micron, likely due to silicates and proto-silicates, as well as strong ionic lines of [Ar II], [Ar III], [S IV] and [Ne II]. In these locations, the dust and ionic emission originate from the explosion's O-burning layers. The regions where Channels 2 (4.5 micron) and 3 (5.6 mi...

  7. Mid-IR Spectra of Refractory Minerals Relevant to Comets

    Science.gov (United States)

    Jauhari, Shekeab

    2008-09-01

    On 4 July 2005 the Spitzer Space Telescope obtained mid-IR ( 5-40 µm) spectra of the ejecta from the hypervelocity impact of the Deep Impact projectile with comet 9P/Tempel 1. Spectral modeling demonstrates that there are abundant minerals present in the ejecta including Ca/Fe/Mg-rich silicates, carbonates, phyllosilicates, water ice, amorphous carbon, and sulfides [1]. However, precise mineralogical identifications are hampered by the lack of comprehensive 5 - 40 µm spectral measurements of the emissivity for a broad compositional range of these materials. Here, we present our initial results for 2 - 50 µm transmission spectra and absorption constants for materials relevant to comets, including pyrrhotite, pyrite, and several phyllosilicate (clay) minerals. Measuring the transmission of materials over the full spectral range sensitive by Spitzer requires grinding the minerals into submicron powders and then mixing them with KBr (for the 1-25 um region) and polyethylene (16-50 um region) to form pellets. Transmission measurements of sub-micron sulfides are particularly difficult to obtain because the minerals oxidize rapidly upon grinding and subsequent handling unless special care is taken. A detailed description of our sample preparation and measurement technique will be provided to assist other researchers in their attempts to acquire similar spectra. References: [1] Lisse, C.M. et al., Science 313, 635 - 640 (2006)

  8. Structure of high-resolution NMR spectra

    CERN Document Server

    Corio, PL

    2012-01-01

    Structure of High-Resolution NMR Spectra provides the principles, theories, and mathematical and physical concepts of high-resolution nuclear magnetic resonance spectra.The book presents the elementary theory of magnetic resonance; the quantum mechanical theory of angular momentum; the general theory of steady state spectra; and multiple quantum transitions, double resonance and spin echo experiments.Physicists, chemists, and researchers will find the book a valuable reference text.

  9. A study of ice response spectra

    Institute of Scientific and Technical Information of China (English)

    LIU Chunguang; JIA Lingling

    2009-01-01

    Some problems concerning the ice forces and ice response spectra are studied from both theoretical and practical points of view. On the basis of structural analysis,the analysis method of ice response spectra is proposed, since it plays an important role in the prediction of maximum structural response in cold regions. And it is illustrated that it is easy to study the structural response to ice using the ice response spectra.

  10. Circumstellar Molecular Spectra towards Evolved Stars

    CERN Document Server

    Bakker, E J

    1997-01-01

    In this paper we discuss the relevance of, and possible scientific gains which can be acquired from studying circumstellar molecular spectra toward evolved stars. Where can we expect circumstellar molecular spectra, why would we want to study these spectra, which molecules might be present, and what can we learn from these studies? We present an overview of reported detections, and discuss some of the results.

  11. Calculation of reactor antineutrino spectra in TEXONO

    CERN Document Server

    Chen Dong Liang; Mao Ze Pu; Wong, T H

    2002-01-01

    In the low energy reactor antineutrino physics experiments, either for the researches of antineutrino oscillation and antineutrino reactions, or for the measurement of abnormal magnetic moment of antineutrino, the flux and the spectra of reactor antineutrino must be described accurately. The method of calculation of reactor antineutrino spectra was discussed in detail. Furthermore, based on the actual circumstances of NP2 reactors and the arrangement of detectors, the flux and the spectra of reactor antineutrino in TEXONO were worked out

  12. Thermal luminescence spectra of polyamides and their Maillard reaction with reducing sugars.

    Science.gov (United States)

    Karakisawa, Taketo; Yamada, Taishi; Sekine, Masahiko; Ishii, Hiroshi; Satoh, Chikahiro; Millington, Keith R; Nakata, Munetaka

    2012-01-01

    Thermal luminescence (TL) spectra of polyamides were measured with a Fourier-transform chemiluminescence spectrometer to elucidate the emission mechanism. A TL band of ε-polylysine with a peak at 542 nm observed at 403 K was assigned to the emission due to the interaction of the -CO-NH- group with oxygen molecules by comparison with nylon-6, polyglycine, and polyalanine. When the sample was kept at 453 K, the intensity of the TL band decreased and the wavelength of the peak shifted to 602 nm, which was assigned to the emission due to the interaction of the NH2 group on the side chain with oxygen molecules by comparison with monomeric lysine. A weak emission with a peak at 668 nm was assigned to the advanced glycosylation end products (AGEs) yielded by the Maillard reaction with a catalytic amount of water. To understand this reaction and to examine the TL emission of AGEs, we measured TL spectra of mixtures of polylysine and reducing sugars such as glucose, maltose, lactose, and dextrin. The minimum temperature for TL emission, wavelength of the peak and the relative intensities of the TL emission were found to depend on the size of the sugars.

  13. Spectra of Velocity components over Complex Terrain

    DEFF Research Database (Denmark)

    Panofsky, H. A.; Larko, D.; Lipschut, R.

    1982-01-01

    Spectra have been measured over a variety of types of complex terrain: on tops of hills and escarpments, over land downstream of a water surface, and over rolling terrain. Differences between spectra over many types of complex terrain, and over uniform terrain, can be explained by these hypotheses...... is horizontal, and decrease when the flow is uphill, for the longitudinal velocity component only. Since vertical-velocity spectra contain relatively less low wavenumber energy than horizontal-velocity spectra, energetic vertical-velocity fluctuations tend to be in equilibrium with local terrain....

  14. Optical absorption spectra of Ag-11 isomers

    DEFF Research Database (Denmark)

    Martinez, Jose Ignacio; Fernandez, E. M.

    2009-01-01

    The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground-stale confi......The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground...

  15. Estimation of emission cone wall thickness of Jupiter's decametric radio emission using stereoscopic STEREO/WAVES observations

    Science.gov (United States)

    Panchenko, M.; Rucker, H. O.

    2016-11-01

    Aims: Stereoscopic observations by the WAVES instrument onboard two STEREO spacecraft have been used with the aim of estimating wall thickness of an emission cone of Jovian decametric radio emission (DAM). Methods: Stereoscopic observations provided by STEREO-A and -B facilitate unambiguous recognition of the Jovian DAM in observed dynamic spectra as well as identification of its components (Io DAM or non-Io DAM). The dynamic spectra of radio emissions recorded by STEREO/WAVES have been analyzed using the method of cross-correlation of the radio dynamic spectra. Results: Altogether, 139 radio events, in particular 91 Io- and 48 non-Io-related radio events were observed. The averaged width of the emission cone wall for Io-DAM as well as for non-Io DAM is about 1.1° ± 0.2°. These results are in agreement with previous findings.

  16. ELEMENTAL ABUNDANCES IN THE EJECTA OF OLD CLASSICAL NOVAE FROM LATE-EPOCH SPITZER SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Helton, L. Andrew; Vacca, William D. [SOFIA Science Center, USRA, NASA Ames Research Center, M.S. N232-11, Moffett Field, CA 94035 (United States); Gehrz, Robert D.; Woodward, Charles E.; Shenoy, Dinesh P. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street S.E., University of Minnesota, Minneapolis, MN 55455 (United States); Wagner, R. Mark [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Evans, Aneurin [Astrophysics Group, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Krautter, Joachim [Landessternwarte-Zentrum fuer Astronomie der Universitaet, Koenigstuhl, D-69117 Heidelberg (Germany); Schwarz, Greg J. [American Astronomical Society, 2000 Florida Avenue, NW, Suite 400, Washington, DC 20009 (United States); Starrfield, Sumner, E-mail: ahelton@sofia.usra.edu [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287 (United States)

    2012-08-10

    We present Spitzer Space Telescope mid-infrared IRS spectra, supplemented by ground-based optical observations, of the classical novae V1974 Cyg, V382 Vel, and V1494 Aql more than 11, 8, and 4 years after outburst, respectively. The spectra are dominated by forbidden emission from neon and oxygen, though in some cases, there are weak signatures of magnesium, sulfur, and argon. We investigate the geometry and distribution of the late time ejecta by examination of the emission line profiles. Using nebular analysis in the low-density regime, we estimate lower limits on the abundances in these novae. In V1974 Cyg and V382 Vel, our observations confirm the abundance estimates presented by other authors and support the claims that these eruptions occurred on ONe white dwarfs (WDs). We report the first detection of neon emission in V1494 Aql and show that the system most likely contains a CO WD.

  17. Simulations of the Fe K-alpha Energy Spectra from Gravitationally Microlensed Quasars

    CERN Document Server

    Krawczynski, Henric

    2016-01-01

    Chartas et al. (2012, 2016a,b) reported the discovery of multiple and energy variable peaks of the Fe K-alpha emission from the gravitationally lensed quasar RX J1131-1231. The authors explain the observations by the microlensing (produced by the stars of the lensing galaxy) of the emission from different regions of the accretion disk with different Doppler and gravitational frequency shifts. In this paper, we combine detailed simulations of the Fe K-alpha emission of the accretion disk in the Kerr spacetime of the black hole with calculations of the effect of gravitational microlensing on the observed energy spectra. The simulations give multiply peaked energy spectra similar to the observed ones. We explore the dependence of the spectral characteristics on black hole spin, accretion disk inclination, corona height, and microlensing amplification factor, and show that the measurements can be used to constrain these parameters. The detailed simulations described in this paper confirm the earlier constraints o...

  18. Optical spectra of phthalocyanines and related compounds a guide for beginners

    CERN Document Server

    Isago, Hiroaki

    2015-01-01

    This book displays how optical (absorption, emission, and magnetic circular dichroism) spectra of phthalocyanines and related macrocyclic dyes can be varied from their prototypical ones depending on conditions. As these compounds can be involved in colorful chemistry (which might be driven by impurities in solvents), their spectra behave like the sea-god Proteus in their mutability. Therefore, those who have been engaged with phthalocyanines for the first time, including even educated professional researchers and engineers, may have been embarrassed by the deceptive behavior of their compounds and could have, in the worst cases, given up their projects. This book is aimed not merely at reviewing the optical spectra, but also at helping such people, particularly beginners, to figure them out by showing some examples of their prototypical spectra and their variations in several situations. For the purpose of better understanding, the book also provides an introduction to their theoretical backgrounds as graphic...

  19. How Similar are the Properties of Quasars with Nearly Identical Ultraviolet Spectra?

    CERN Document Server

    Rochais, Thomas; Chick, William; Maithil, Jaya; Sutter, Jessica; Brotherton, Michael; Shang, Zhouhui

    2016-01-01

    The spectrum of a quasar contains important information about its properties. Thus, it can be expected that two quasars with similar spectra will have similar properties, but just how similar has not before been quantified. Here we compare the ultraviolet spectra of a sample of 5553 quasars from Data Release 7 of the Sloan Digital Sky Survey, focusing on the $1350$ \\AA \\ $\\leq \\lambda \\leq 2900$ \\AA \\ rest-frame region which contains prominent emission lines from \\SiIV, O IV], \\CIV, \\CIII, and \\MgII\\ species. We use principal component analysis to determine the dominant components of spectral variation, as well as to quantitatively measure spectral similarity. As suggested by both the Baldwin effect and modified Baldwin effect, quasars with similar spectra have similar properties: bolometric luminosity, Eddington fraction, and black hole mass. The latter two quantities are calculated from the luminosity in conjunction with spectral features, and the variation between quasars with virtually identical spectra (...

  20. Estimation of damped oscillation associated spectra from ultrafast transient absorption spectra

    Science.gov (United States)

    van Stokkum, Ivo H. M.; Jumper, Chanelle C.; Snellenburg, Joris J.; Scholes, Gregory D.; van Grondelle, Rienk; Malý, Pavel

    2016-11-01

    When exciting a complex molecular system with a short optical pulse, all chromophores present in the system can be excited. The resulting superposition of electronically and vibrationally excited states evolves in time, which is monitored with transient absorption spectroscopy. We present a methodology to resolve simultaneously the contributions of the different electronically and vibrationally excited states from the complete data. The evolution of the excited states is described with a superposition of damped oscillations. The amplitude of a damped oscillation cos(ωnt)exp(-γnt) as a function of the detection wavelength constitutes a damped oscillation associated spectrum DOASn(λ) with an accompanying phase characteristic φn(λ). In a case study, the cryptophyte photosynthetic antenna complex PC612 which contains eight bilin chromophores was excited by a broadband optical pulse. Difference absorption spectra from 525 to 715 nm were measured until 1 ns. The population dynamics is described by four lifetimes, with interchromophore equilibration in 0.8 and 7.5 ps. We have resolved 24 DOAS with frequencies between 130 and 1649 cm-1 and with damping rates between 0.9 and 12 ps-1. In addition, 11 more DOAS with faster damping rates were necessary to describe the "coherent artefact." The DOAS contains both ground and excited state features. Their interpretation is aided by DOAS analysis of simulated transient absorption signals resulting from stimulated emission and ground state bleach.