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1

Source characteristics of Jovian narrow-band kilometric radio emissions  

Microsoft Academic Search

New observations of Jovian narrow-band kilometric (nKOM) radio emissions were made by the Unified Radio and Plasma Wave (URAP) experiment on the Ulysses spacecraft during the Ulysses-Jupiter encounter in early February 1992. These observations have demonstrated the unique capability of the URAP instrument for determining both the direction and polarization of nKOM radio sources. An important result is the discovery

M. J. Reiner; J. Fainberg; R. G. Stone; M. L. Kaiser; M. D. Desch; R. Manning; P. Zarka; B.-M. Pedersen

1993-01-01

2

Source characteristics of Jovian narrow-band kilometric radio emissions  

NASA Technical Reports Server (NTRS)

New observations of Jovian narrow-band kilometric (nKOM) radio emissions were made by the Unified Radio and Plasma Wave (URAP) experiment on the Ulysses spacecraft during the Ulysses-Jupiter encounter in early February 1992. These observations have demonstrated the unique capability of the URAP instrument for determining both the direction and polarization of nKOM radio sources. An important result is the discovery that nKOM radio emission originates from a number of distinct sources located at different Jovian longitudes and at the inner and outermost regions of the Io plasma torus. These sources have been tracked for several Jovian rotations, yielding their corotational lags, their spatial and temporal evolution, and their radiation characteristics at both low latitudes far from Jupiter and at high latitudes near the planet. Both right-hand and left-hand circularly polarized nKOM sources were observed. The polarizations observed for sources in the outermost regions of the torus seem to favor extraordinary mode emission.

Reiner, M. J.; Fainberg, J.; Stone, R. G.; Kaiser, M. L.; Desch, M. D.; Manning, R.; Zarka, P.; Pedersen, B.-M.

1993-01-01

3

A contribution to the selection of emission-line galaxies using narrow-band filters in the optical airglow windows  

E-print Network

Emission line galaxies are an invaluable tool for our understanding of the evolution of galaxies in the Universe. Imaging of deep fields with narrow-band filters allows not only the selection of these objects, but also to infer the line flux and the equivalent width of the emission line with some assumptions. The narrow-band filter technique provides homogeneous samples of galaxies in small comoving volumes in the sky. We present an analysis of the selection of emission-line galaxies using narrow-band filters. Different methods of observation are considered: broad-band -- narrow-band filters and two broad-band and one narrow-band filters. We study also the effect of several lines entering simultaneously inside the filters (this is the case of Halpha). In each case the equations to obtain the equivalent width and line flux from the photometry are obtained. Candidates to emission-line objects are selected by their color excess in a magnitude-color diagram. For different narrow-band filters, we compute the mean colors of stars and galaxies, showing that, apart from galaxies, some types of stars could be selected with certain filter sets. We show how to compute the standard deviation of the colors of the objects even in the usual case when there are not enough objects to determine the standard deviation from the data. We present also helpful equations to compute the narrow-band and the broad-band exposure times in order to obtain minimum dispersion in the ratio of fluxes of both bands with minimum total exposure time.

Sergio Pascual; Jesus Gallego; Jaime Zamorano

2006-11-03

4

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

NASA Astrophysics Data System (ADS)

Recently, chlorophyll fluorescence (ChlF) retrievals in narrow spectral regions (< 1 nm, between 750-770 nm) of the near infrared (NIR) region of Earth's reflected radiation have been achieved from satellites, including the Japanese GOSAT and the European Space Agency's Sciamachy/Envisat. However, these retrievals sample the total full-spectrum ChlF and are made at non-optimal wavelengths since they are not located at the peak fluorescence emission features. We wish to estimate the total full-spectrum ChlF based on emissions obtained at selected wavelengths. For this, we drew upon leaf emission spectra measured on corn leaves obtained from a USDA experimental cornfield in MD (USA). These emission spectra were determined for the adaxial and abaxial (i.e., top and underside) surfaces of leaves measured throughout the 2008 and 2011 growing seasons (n>400) using a laboratory instrument (Fluorolog-3, Horiba Scientific, USA), recorded in either 1 nm or 5 nm increments with monochromatic excitation wavelengths of either 532 or 420 nm. The total ChlF signal was computed as the area under the continuous spectral emission curves, summing the emission intensities (counts per second) per waveband. The individual narrow (1 or 5 nm) waveband emission intensities were linearly related to full emission values, with variable success across the spectrum. Equations were developed to estimate total ChlF from these individual wavebands. Here, we report the results for the average adaxial/abaxial emissions. Very strong relationships were achieved for the relatively high fluorescence intensities at the red chlorophyll peak, centered at 685 nm (r2= 0.98, RMSE = 5.53 x 107 photons/s) and in the nearby O2-B atmospheric absorption feature centered at 688 nm (r2 = 0.94, RMSE = 4.04 x 107), as well as in the far-red peak centered at 740 nm (r2=0.94, RMSE = 5.98 x107). Very good retrieval success occurred for the O2-A atmospheric absorption feature on the declining NIR shoulder centered at 760 nm (r2 = 0.88, RMSE = 7.54 x 107). When perfect retrievals were assumed (0% noise), retrievals remained good in the low emission regions on either side of the peaks-- those associated with the H alpha line at 655 nm (r2 = 0.83, RMSE =8.87 x 107) and the far-NIR wavelengths recently utilized for satellite retrievals: a K line at 770 nm (r2 = 0.85, RMSE = 8.36 x 107) and the 750-770 nm interval (r2 = 0.88, RMSE = 6.92 x 107). However, the atmosphere and satellite observations are expected to add noise to retrievals. Adding 5% random error to these relationships did not seriously impair the retrieval successes in the red and far-red peaks (r2 ~ 0.85, RMSEs = 6.31 x 107). A greater impact occurred (reducing retrieval success by ~10%) when adding 5% noise for the far-NIR narrow band at 770 nm (r2 ~ 0.70, RMSE ~ 8.5 x 107). When a 10% random error was added, the retrieval successes fell to ~68 ± 7% for all retrieval wavebands, and RMSEs increased by a factor of 10. This laboratory approach will be critical to calibrate space borne retrievals, but additional information across plant species is needed. Furthermore, this experiment indicates that ChlF retrievals from space should include information from the red and far-red peak emission regions, since the true total fluorescence signal is the desired parameter for Earth carbon and energy budgets.

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

2012-12-01

5

Enhanced tunable narrow-band THz emission from laser-modulated electron beams  

SciTech Connect

We propose and analyze a scheme to generate enhanced narrow-band terahertz (THz) radiation through down-conversion of the frequency of optical lasers using laser-modulated electron beams. In the scheme the electron beam is first energy modulated by two lasers with wave numbers k{sub 1} and k2, respectively. After passing through a dispersion section, the energy modulation is converted to density modulation. Due to the nonlinear conversion process, the beam will have density modulation at wave number k = nk{sub 1} + mk{sub 2}, where n and m are positive or negative integers. By properly choosing the parameters for the lasers and dispersion section, one can generate density modulation at THz frequency in the beam using optical lasers. This density-modulated beam can be used to generate powerful narrow-band THz radiation. Since the THz radiation is in tight synchronization with the lasers, it should provide a high temporal resolution for the optical-pump THz-probe experiments. The central frequency of the THz radiation can be easily tuned by varying the wavelength of the two lasers and the energy chirp of the electron beam. The proposed scheme is in principle able to generate intense narrow-band THz radiation covering the whole THz range and offers a promising way towards the tunable intense narrow-band THz sources.

Xiang, D.; Stupakov, G.; /SLAC

2009-06-19

6

Hybrid semiconducting polymer dot-quantum dot with narrow-band emission, near-infrared fluorescence, and high brightness.  

PubMed

This communication describes a new class of semiconducting polymer nanoparticle-quantum dot hybrid with high brightness, narrow emission, near-IR fluorescence, and excellent cellular targeting capability. Using this approach, we circumvented the current difficulty with obtaining narrow-band-emitting and near-IR-fluorescing semiconducting polymer nanoparticles while combining the advantages of both semiconducting polymer nanoparticles and quantum dots. We further demonstrated the use of this new class of hybrid nanomaterial for effective and specific cellular and subcellular labeling without any noticeable nonspecific binding. This hybrid nanomaterial is anticipated to find use in a variety of in vitro and in vivo biological applications. PMID:22515545

Chan, Yang-Hsiang; Ye, Fangmao; Gallina, Maria Elena; Zhang, Xuanjun; Jin, Yuhui; Wu, I-Che; Chiu, Daniel T

2012-05-01

7

Narrow-band PMD Measurements  

E-print Network

by natural or induced birefringence in the optical transmission medium, which in turn causes polarization measurements on narrow-band devices using the Agilent 8509B Lightwave Polarization Analyzer #12;Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 2 #12;I. Introduction This product note provides information about making narrow-band Polarization

Park, Namkyoo

8

A very narrow spectral band  

Microsoft Academic Search

The power spectrum of the variable z in the Lorenz equations with sigma=10, b=8\\/3, and r=200 appeared in previous work to contain a line superposed on a continuum. Analysis of an extended solution into consecutive segments with rather similar initial states, each segment spanning at least seven maxima of z, shows that the apparent line is actually a narrow band.

Edward N. Lorenz

1984-01-01

9

A very narrow spectral band  

Microsoft Academic Search

The power spectrum of the variablez in the Lorenz equations with s=10,b=8\\/3, andr=200 appeared in previous work to contain a line superposed on a continuum. Analysis of an extended solution into consecutive segments with rather similar initial states, each segment spanning at least seven maxima ofz, shows that the apparent line is actually a narrow band. Solutions spanning at least

Edward N. Lorenz

1984-01-01

10

A Fluorescent Indicator for Imaging Lysosomal Zinc(II) with Förster Resonance Energy Transfer (FRET)-Enhanced Photostability and a Narrow Band of Emission.  

PubMed

We demonstrate a strategy to transfer the zinc(II) sensitivity of a fluoroionophore with low photostability and a broad emission band to a bright and photostable fluorophore with a narrow emission band. The two fluorophores are covalently connected to afford an intramolecular Förster resonance energy transfer (FRET) conjugate. The FRET donor in the conjugate is a zinc(II)-sensitive arylvinylbipyridyl fluoroionophore, the absorption and emission of which undergo bathochromic shifts upon zinc(II) coordination. When the FRET donor is excited, efficient intramolecular energy transfer occurs to result in the emission of the acceptor boron dipyrromethene (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene or BODIPY) as a function of zinc(II) concentration. The broad emission band of the donor/zinc(II) complex is transformed into the strong, narrow emission band of the BODIPY acceptor in the FRET conjugates, which can be captured within the narrow emission window that is preferred for multicolor imaging experiments. In addition to competing with other nonradiative decay processes of the FRET donor, the rapid intramolecular FRET of the excited FRET-conjugate molecule protects the donor fluorophore from photobleaching, thus enhancing the photostability of the indicator. FRET conjugates 3 and 4 contain aliphatic amino groups, which selectively target lysosomes in mammalian cells. This subcellular localization preference was verified by using confocal fluorescence microscopy, which also shows the zinc(II)-enhanced emission of 3 and 4 in lysosomes. It was further shown using two-color structured illumination microscopy (SIM), which is capable of extending the lateral resolution over the Abbe diffraction limit by a factor of two, that the morpholino-functionalized compound 4 localizes in the interior of lysosomes, rather than anchoring on the lysosomal membranes, of live HeLa cells. PMID:25382395

Sreenath, Kesavapillai; Yuan, Zhao; Allen, John R; Davidson, Michael W; Zhu, Lei

2015-01-01

11

A Fluorescent Indicator for Imaging Lysosomal Zinc(II) with Förster Resonance Energy Transfer (FRET)-Enhanced Photostability and a Narrow Band of Emission.  

PubMed

We demonstrate a strategy to transfer the zinc(II) sensitivity of a fluoroionophore with low photostability and a broad emission band to a bright and photostable fluorophore with a narrow emission band. The two fluorophores are covalently connected to afford an intramolecular Förster resonance energy transfer (FRET) conjugate. The FRET donor in the conjugate is a zinc(II)-sensitive arylvinylbipyridyl fluoroionophore, the absorption and emission of which undergo bathochromic shifts upon zinc(II) coordination. When the FRET donor is excited, efficient intramolecular energy transfer occurs to result in the emission of the acceptor boron dipyrromethene (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene or BODIPY) as a function of zinc(II) concentration. The broad emission band of the donor/zinc(II) complex is transformed into the strong, narrow emission band of the BODIPY acceptor in the FRET conjugates, which can be captured within the narrow emission window that is preferred for multicolor imaging experiments. In addition to competing with other nonradiative decay processes of the FRET donor, the rapid intramolecular FRET of the excited FRET-conjugate molecule protects the donor fluorophore from photobleaching, thus enhancing the photostability of the indicator. FRET conjugates 3 and 4 contain aliphatic amino groups, which selectively target lysosomes in mammalian cells. This subcellular localization preference was verified by using confocal fluorescence microscopy, which also shows the zinc(II)-enhanced emission of 3 and 4 in lysosomes. It was further shown using two-color structured illumination microscopy (SIM), which is capable of extending the lateral resolution over the Abbe diffraction limit by a factor of two, that the morpholino-functionalized compound 4 localizes in the interior of lysosomes, rather than anchoring on the lysosomal membranes, of live HeLa cells. PMID:25378058

Sreenath, Kesavapillai; Yuan, Zhao; Allen, John R; Davidson, Michael W; Zhu, Lei

2014-11-01

12

A 1.1-1.9 GHz SETI Survey of the Kepler Field. I. A Search for Narrow-band Emission from Select Targets  

NASA Astrophysics Data System (ADS)

We present a targeted search for narrow-band (<5 Hz) drifting sinusoidal radio emission from 86 stars in the Kepler field hosting confirmed or candidate exoplanets. Radio emission less than 5 Hz in spectral extent is currently known to only arise from artificial sources. The stars searched were chosen based on the properties of their putative exoplanets, including stars hosting candidates with 380 K > T eq > 230 K, stars with five or more detected candidates or stars with a super-Earth (R p < 3 R ?) in a >50 day orbit. Baseband voltage data across the entire band between 1.1 and 1.9 GHz were recorded at the Robert C. Byrd Green Bank Telescope between 2011 February and April and subsequently searched offline. No signals of extraterrestrial origin were found. We estimate that fewer than ~1% of transiting exoplanet systems host technological civilizations that are radio loud in narrow-band emission between 1 and 2 GHz at an equivalent isotropically radiated power (EIRP) of ~1.5 × 1021 erg s-1, approximately eight times the peak EIRP of the Arecibo Planetary Radar, and we limit the number of 1-2 GHz narrow-band-radio-loud Kardashev type II civilizations in the Milky Way to be {<}10^{-6}\\ M^{-1}_\\odot. Here we describe our observations, data reduction procedures and results.

Siemion, Andrew P. V.; Demorest, Paul; Korpela, Eric; Maddalena, Ron J.; Werthimer, Dan; Cobb, Jeff; Howard, Andrew W.; Langston, Glen; Lebofsky, Matt; Marcy, Geoffrey W.; Tarter, Jill

2013-04-01

13

A 1.1-1.9 GHz SETI SURVEY OF THE KEPLER FIELD. I. A SEARCH FOR NARROW-BAND EMISSION FROM SELECT TARGETS  

SciTech Connect

We present a targeted search for narrow-band (<5 Hz) drifting sinusoidal radio emission from 86 stars in the Kepler field hosting confirmed or candidate exoplanets. Radio emission less than 5 Hz in spectral extent is currently known to only arise from artificial sources. The stars searched were chosen based on the properties of their putative exoplanets, including stars hosting candidates with 380 K > T{sub eq} > 230 K, stars with five or more detected candidates or stars with a super-Earth (R{sub p} < 3 R{sub Circled-Plus }) in a >50 day orbit. Baseband voltage data across the entire band between 1.1 and 1.9 GHz were recorded at the Robert C. Byrd Green Bank Telescope between 2011 February and April and subsequently searched offline. No signals of extraterrestrial origin were found. We estimate that fewer than {approx}1% of transiting exoplanet systems host technological civilizations that are radio loud in narrow-band emission between 1 and 2 GHz at an equivalent isotropically radiated power (EIRP) of {approx}1.5 Multiplication-Sign 10{sup 21} erg s{sup -1}, approximately eight times the peak EIRP of the Arecibo Planetary Radar, and we limit the number of 1-2 GHz narrow-band-radio-loud Kardashev type II civilizations in the Milky Way to be <10{sup -6} M{sub Sun }{sup -1}. Here we describe our observations, data reduction procedures and results.

Siemion, Andrew P. V.; Korpela, Eric; Werthimer, Dan; Cobb, Jeff; Lebofsky, Matt; Marcy, Geoffrey W. [University of California, Berkeley, 110 Sproul Hall, Berkeley, CA 94720 (United States)] [University of California, Berkeley, 110 Sproul Hall, Berkeley, CA 94720 (United States); Demorest, Paul; Maddalena, Ron J.; Langston, Glen [National Radio Astronomy Observatory, 520 Edgemont Rd Charlottesville, VA 22903 (United States)] [National Radio Astronomy Observatory, 520 Edgemont Rd Charlottesville, VA 22903 (United States); Howard, Andrew W. [Institute for Astronomy, University of Hawaii, 640 North A'ohoku Place, 209 Hilo, HI 96720-2700 (United States)] [Institute for Astronomy, University of Hawaii, 640 North A'ohoku Place, 209 Hilo, HI 96720-2700 (United States); Tarter, Jill [SETI Institute, 189 Bernardo Ave 100 Mountain View, CA 94043 (United States)] [SETI Institute, 189 Bernardo Ave 100 Mountain View, CA 94043 (United States)

2013-04-10

14

Narrow band gap amorphous silicon semiconductors  

DOEpatents

Disclosed is a narrow band gap amorphous silicon semiconductor comprising an alloy of amorphous silicon and a band gap narrowing element selected from the group consisting of Sn, Ge, and Pb, with an electron donor dopant selected from the group consisting of P, As, Sb, Bi and N. The process for producing the narrow band gap amorphous silicon semiconductor comprises the steps of forming an alloy comprising amorphous silicon and at least one of the aforesaid band gap narrowing elements in amount sufficient to narrow the band gap of the silicon semiconductor alloy below that of amorphous silicon, and also utilizing sufficient amounts of the aforesaid electron donor dopant to maintain the amorphous silicon alloy as an n-type semiconductor.

Madan, A.; Mahan, A.H.

1985-01-10

15

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Analysis of the outlook for using narrow-band spontaneous emission sources for atmospheric air purification  

NASA Astrophysics Data System (ADS)

The outlook for using narrow-band spontaneous emission sources for purification of smoke gases from sulphur and nitrogen oxides is demonstrated by calculations based on a nonstationary kinetic model of the N2 — O2 — H2O — CO2 — SO2 mixture. The dependences of the mixture purification efficiency on the UV source power at different wavelengths, the exposure time, and the mixture temperature are calculated. It is shown that the radiation sources proposed in the paper will provide better purification of waste gases in the atmosphere. The most promising is a KrCl* lamp emitting an average power of no less than 100 W at 222 nm.

Boyarchuk, K. A.; Karelin, A. V.; Shirokov, R. V.

2003-12-01

16

Multilayer dielectric narrow band mangin mirror  

NASA Astrophysics Data System (ADS)

The design of multilayer stack of dielectric films for narrow band mirror is developed using thin film coating software. The proposed design is materialized by employing thin film coating (PVD) method and reflectance in narrow band spectrum range is achieved. Thickness of high and low refractive index material is taken precisely up to nanometer level. The curved coated substrate is cemented with another K9 matching substrate that forms a Mangin mirror for wavelength 650nm. Narrow band mirrors with reflectivity more than 90% has been produced by properly stacking of 21 layers and advantage of the use of this type of mirror as an interference filter is discussed.

Ahmed, K.; Khan, A. N.; Rauf, A.; Gul, A.

2014-06-01

17

The Stellar Population and Star Formation Rates of z~1.5-1.6 [O II] Emitting Galaxies Selected from Narrow-Band Emission-Line Surveys  

E-print Network

We present the first detailed study of the stellar populations of star-forming galaxies at z~1.5, which are selected by their [O II] emission line, detected in narrow-band surveys. We identified ~1,300 [O II] emitters at z=1.47 and z=1.62 in the Subaru Deep Field with rest-frame EWs above 13\\AA. Optical and near-infrared spectroscopic observations for ~10% of our samples show that our two-color identification of [O II] emission-line galaxies is 99% successful. We analyze the multi-wavelength properties of a subset of ~1,200 galaxies with the best photometry. They have average rest-frame EW of 45\\AA, stellar mass of 3 x 10^9 M_sun, and stellar age of 100 Myr. In addition, our SED fitting and broad-band colors indicate that [O II] emitters span the full range of galaxy populations at z~1.5. We also find that 80% of [O II] emitters are also photometrically classified as "BX/BM" (UV) galaxies and/or the star-forming "BzK" (near-IR) galaxies. Our [O II] emission line survey produces a far more complete, and somewh...

Ly, Chun; Kashikawa, Nobunari; Hayashi, Masao; Nagao, Tohru; Shimasaku, Kazuhiro; Ota, Kazuaki; Ross, Nathaniel R

2012-01-01

18

Narrow-Band Applications of Communications Satellites.  

ERIC Educational Resources Information Center

This paper attempts to describe the advantages of "narrow-band" applications of communications satellites for education. It begins by discussing the general controversy surrounding the use of satellites in education, by placing the concern within the larger context of the general debate over the uses of new technologies in education, and by…

Cowlan, Bert; Horowitz, Andrew

19

Photosensized Controlling Benzyl Methacrylate-Based Matrix Enhanced Eu3+ Narrow-Band Emission for Fluorescence Applications  

PubMed Central

This study synthesized a europium (Eu3+) complex Eu(DBM)3Cl-MIP (DBM = dibenzoyl methane; Cl-MIP = 2-(2-chlorophenyl)-1-methyl-1H-imidazo[4,5-f][1,10]phenanthroline) dispersed in a benzyl methacrylate (BMA) monomer and treated with ultraviolet (UV) light for polymerization. Spectral results showed that the europium complex containing an antenna, Cl-MIP, which had higher triplet energy into the Eu3+ energy level, was an energetically enhanced europium emission. Typical stacking behaviors of ?–? interactions between the ligands and the Eu3+-ion were analyzed using single crystal X-ray diffraction. Regarding the luminescence performance of this europium composite, the ligand/defect emission was suppressed by dispersion in a poly-BMA (PBMA) matrix. The underlying mechanism of the effective enhancement of the pure Eu3+ emission was attributed to the combined effects of structural modifications, defect emissions, and carrier charge transfer. Fluorescence spectra were compared to the composite of optimized Eu3+ emission where they were subsequently chelated to four metal ions via carboxylate groups on the BMA unit. The optical enhanced europium composite clearly demonstrated highly efficient optical responses and is, therefore a promising application as an optical detection material. PMID:22489178

Lee, Jiann-Fong; Chen, Hsuen-Li; Lee, Geneh-Siang; Tseng, Shao-Chin; Lin, Mei-Hsiang; Liau, Wen-Bin

2012-01-01

20

THZ EMISSION SPECTROSCOPY OF NARROW BANDGAP SEMICONDUCTORS  

E-print Network

THZ EMISSION SPECTROSCOPY OF NARROW BANDGAP SEMICONDUCTORS By Ricardo Asc´azubi A Thesis Submitted-Domain Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 Optically Excited THz Emission Processes Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.1 THz-TDS Setup

Wilke, Ingrid

21

Narrow band 3 × 3 Mueller polarimetric endoscopy.  

PubMed

Mueller matrix polarimetric imaging has shown potential in tissue diagnosis but is challenging to implement endoscopically. In this work, a narrow band 3 × 3 Mueller matrix polarimetric endoscope was designed by rotating the endoscope to generate 0°, 45° and 90° linearly polarized illumination and positioning a rotating filter wheel in front of the camera containing three polarisers to permit polarization state analysis for backscattered light. The system was validated with a rotating linear polarizer and a diffuse reflection target. Initial measurements of 3 × 3 Mueller matrices on a rat are demonstrated, followed by matrix decomposition into the depolarization and retardance matrices for further analysis. Our work shows the feasibility of implementing polarimetric imaging in a rigid endoscope conveniently and economically in order to reveal diagnostic information. PMID:24298405

Qi, Ji; Ye, Menglong; Singh, Mohan; Clancy, Neil T; Elson, Daniel S

2013-01-01

22

Narrow band 3 × 3 Mueller polarimetric endoscopy  

PubMed Central

Mueller matrix polarimetric imaging has shown potential in tissue diagnosis but is challenging to implement endoscopically. In this work, a narrow band 3 × 3 Mueller matrix polarimetric endoscope was designed by rotating the endoscope to generate 0°, 45° and 90° linearly polarized illumination and positioning a rotating filter wheel in front of the camera containing three polarisers to permit polarization state analysis for backscattered light. The system was validated with a rotating linear polarizer and a diffuse reflection target. Initial measurements of 3 × 3 Mueller matrices on a rat are demonstrated, followed by matrix decomposition into the depolarization and retardance matrices for further analysis. Our work shows the feasibility of implementing polarimetric imaging in a rigid endoscope conveniently and economically in order to reveal diagnostic information. PMID:24298405

Qi, Ji; Ye, Menglong; Singh, Mohan; Clancy, Neil T.; Elson, Daniel S.

2013-01-01

23

Narrow band images of suspected cooling flow galaxies  

NASA Technical Reports Server (NTRS)

Narrow-band (H alpha and (NII)) charge coupled device (CCD) images of elliptical galaxies suspected of having cooling flows are discussed. Researchers find evidence of optical emission from cool gas which is most likely associated with a cooling flow. At least 4 galaxies (NGC 3998, NGC 4203, NGC 4550 and NGC 4697) show emission of (NII) and/or H alpha within the central 20 seconds, a fraction consistent with results from Phillips et al. (1987) and Caldwell (1984). In these four, (NII) lambda 6584A emission is stronger than H alpha (which is often in absorption e.g., as seen in long slit spectra of NGC4697). From long slit spectra of these galaxies, Deustua and Teske (1989) infer electron densities, N sub e, of order 1.2x10 to the 3rd power cm(-3) assuming T = 10 to the 4th power K for the optically emitting gas. NGC 2685, NGC 3489 appear to have emission in (NII); NGC 4636 may also, but, is difficult to see in the data (Demoulin-Ulrich, Butcher and Boksenberg (1984) did not see emission from this galaxy). NGC 4472, NGC 4473, NGC 4365, NGC 4638 and NGC 4649 show no emission.

Deustua, Susana; Bothun, Greg

1990-01-01

24

The Narrow-Band Model and Semi-Conductor Theory  

ERIC Educational Resources Information Center

Applies the narrow-band model to the instruction of intrinsic and extrinsic semiconductors along with the phenomenon of compensation. Advocates the model for undergraduate instruction due to its intuitive appeal and mathematical simplicity. (CP)

Tanner, B. K.

1976-01-01

25

Ultrafast Narrow Band Modulation of VCSELs  

NASA Technical Reports Server (NTRS)

Multimode beating was greatly enhanced by taking output from part (e.g., half) of the output facet. Simpler sources of microwaves and millimeter waves of various frequencies were generated by varying the VCSEL diameter in a single multimode VCSEL our coupling of a few VCSELs. Breathing frequency in multi-mode operations affects modulation response and bandwidth. Optimizing RO frequency and mode beating frequency could potentially expand bandwidths suitable for wide band digital communications.

Ning, Cun-Zheng; Biegel, Bryan A. (Technical Monitor)

2002-01-01

26

Comparison of broad-band and narrow-band red and near-infrared vegetation indices  

Microsoft Academic Search

An experiment has been conducted in which narrow-band field reflectance spectra were acquired of a rooted pinyon pine canopy with five different gravel backgrounds. Leaf area was successively removed as the measurements were repeated. From these reflectance spectra, narrow-band and broad-band (AVHRR, TM, MSS) red and near-infrared (NIR) vegetation index values were calculated. The performance of the vegetation indices was

Christopher D. Elvidge; Zhikang Chen

1995-01-01

27

A narrow band graph partitioning method for skin lesion segmentation  

Microsoft Academic Search

Accurate skin lesion segmentation is critical for automated early skin cancer detection and diagnosis. In this paper, we present a novel multi-modal skin lesion segmentation method based on region fusion and narrow band energy graph partitioning. The proposed method can handle challenging characteristics of skin lesions, such as topological changes, weak or false edges, and asymmetry. Extensive testing demonstrated that

Xiaojing Yuan; Ning Situ; George Zouridakis

2009-01-01

28

Narrow-Band WGM Optical Filters With Tunable FSRs  

NASA Technical Reports Server (NTRS)

Optical resonators of the whispering-gallery-mode (WGM) type featuring DC-tunable free spectral ranges (FSRs) have been demonstrated. By making the FSR tunable, one makes it possible to adjust, during operation, the frequency of a microwave signal generated by an optoelectronic oscillator in which an WGM optical resonator is utilized as a narrow-band filter.

Mohageg, Makan; Matsko, Andrey; Savchenkov, Anatoliy; Maleki, Lute; Iltchenko, Vladimir; Strekalov, Dmitry

2007-01-01

29

Limits on neutrino oscillations in the Fermilab narrow band beam  

SciTech Connect

A search for neutrino oscillations was made using the Fermilab narrow-band neutrino beam and the 15 ft. bubble chamber. No positive signal for neutrino oscillations was observed. Limits were obtained for mixing angles and neutrino mass differences for nu/sub ..mu../ ..-->.. nu/sub e/, nu/sub ..mu../ ..-->.. nu/sub tau/, nu/sub e/ ..-->.. nu/sub e/. 5 refs.

Brucker, E.B.; Jacques, P.F.; Kalelkar, M.; Koller, E.L.; Plano, R.J.; Stamer, P.E.; Baker, N.J.; Connolly, P.L.; Kahn, S.A.; Murtagh, M.J.

1986-01-01

30

Local level set segmentation method combined with narrow band  

NASA Astrophysics Data System (ADS)

The paper deduces a general form of energy function from the level set method based on Mumford-Shah model. It introduces the gradient of image features into the energy function, which could make the segmentation more precise and the algorithm converge faster. In order to detect local object in the image with clutter background, a local level set segmentation method using the proposed energy function is presented in this paper. The method combined with narrow band could obtain local optimal segmentation, which just needs prior location of the object. To tackle the problem that the calculation cost of level set is so expensive, the paper proposes an efficient algorithm for narrow band which implements very fast. The algorithm starts with a simple initial curve, and then it only updates the level set function in the narrow band. The local level set method is applied successfully to image segmentation with cluttered background, multi-object detection and moving object detection. The results of the experiments are presented in the end of paper.

Li, Yushi; Zhou, Jun; Li, Junlong; Liu, Chunsheng

2007-11-01

31

Narrow-Band Spectrophotometry of Comet Hale-Bopp (C/1995 O1) Near Perihelion I.: Photometric Behavior of C2, C3, CN Molecular Bands  

NASA Astrophysics Data System (ADS)

We present the results from narrow-band spectrophotometry of Comet Hale-Bopp (C/1995 O1) near perihelion obtained at Sobaeksan Optical Astronomy Observatory 61cm telescope equipped with PM 512 CCD camera (512 x 512, 0.5''/pixel) and narrow-band filter set for the comet on 19 nights from February 21 to May 1, 1997. We discuss molecular emission band morphology and photometric behavior of Comet Hale-Bopp. The morphology of CN band shows more symmetric light distributions than C2 or C3 bands. On other hand, C2 and C3 band have more compact light distributions than CN band. Similar to wide-band image, molecular band morphology shows spiral structures at the core of the comet. The CN surface brightness variation with changing heliocentric distance shows difference from those of C2 and C.3 The brightness, however, of these molecular bands near perihelion shows previously known 7day period light variations.

Sung, Eon-Chang; Kim, Ho-Il; Youn, Jae-Hyuk

2000-12-01

32

Spectroscopy and Narrow Band Imaging of PAHs in HII regions and Planetary Nebulae using FLITECAM  

NASA Astrophysics Data System (ADS)

FLITECAM, the first light test camera being developed for NASA's SOFIA aircraft has been used successfully on the Shane 120 inch telescope at Lick Observatory on six occasions, most recently to commission the grism spectroscopy mode. Utilizing 3 direct-ruled KRS-5 grisms, this mode provides R 1700 spectroscopy in 9 bands from 1-5 microns for a 1 arcsec slit (2.4 pixels). One of the spectral bands covers the 3.3 micron PAH emission feature. Although difficult to observe from the ground, we have used this emission feature to survey a sample of young and proto-planetary nebulae, carbon stars, and HII regions. On extended sources we also used FLITECAM's wide-field imaging mode to construct narrow-band images centered on and near the 3.3 micron PAH feature. These maps were then used to position FLITECAM's 1 x 60 arcsecond slit on the most prominent areas of PAH emission. The planetary nebulae surveyed with FLITECAM were selected from lists of IRAS and ISO targets. All the selected nebulae have C/O ratios larger than 1, and several targets were known to exhibit PAH emission at longer wavelengths. NGC 7027, a young and highly energetic planetary nebula exhibits the strongest 3.3 micron PAH emission in our survey, as well as strong atomic line emission. Our current sample of 21 PNs shows 12 with PAH emission. None of the carbon stars in our survey showed either PAH or atomic line emission. Narrow band images of the star-forming regions S106, the Orion bar and NGC 1333 reveal clumps of PAH emission. In S106 and Orion the position of peak PAH emission is clearly offset from the position of peak Brackett-Gamma emission by several arcseconds. E. Smith is funded by a NASA GSRP fellowship. Funding for FLITECAM is provided by USRA and UCLA.

Smith, E. C. D.; McLean, I. S.

2006-06-01

33

Compact narrow-band THz radiation source based on photocathode rf gun  

NASA Astrophysics Data System (ADS)

Narrow-band THz coherent Cherenkov radiation can be driven by a subpicosecond electron bunch traveling along the axis of a hollow cylindrical dielectric-lined waveguide. We present a scheme of compact THz radiation source based on the photocathode rf gun. On the basis of our analytic result, the subpicosecond electron bunch with high charge (800 pC) can be generated directly in the photocathode rf gun. According to the analytical and simulated results, a narrow emission spectrum peaked at 0.24 THz with 2 megawatt (MW) peak power is expected to gain in the proposed scheme (the length of the facility is about 1.2 m).

Li, Wei-Wei; He, Zhi-Gang; Jia, Qi-Ka

2014-04-01

34

Elementary energy bands in the band structure of the narrow-band-gap semiconductor CdSb  

NASA Astrophysics Data System (ADS)

Based upon the example of a narrow band gap covalent CdSb crystal (D2h16) , it is shown that a spatial electron density distribution in the unit cell is related to the Zak’s elementary energy bands creating the valence band and to the corresponding Wyckoff positions. A role of particular electronic states in the creation of the elementary energy bands was analyzed by conducting ab initio band structure calculations of CdSb. The investigations of the topology of the elementrary energy bands allows one to predict the nature of chemical bondings in rhombic crystals.

Bercha, D. M.; Slipukhina, I. V.; Sznajder, M.; Rushchanskii, K. Z.

2004-12-01

35

NIR Narrow- and Broad-Band Study of the SSA 22 Field  

NASA Astrophysics Data System (ADS)

Deep narrow- and broad-band near-infrared imaging observations of the central 2'×2' region of the SSA 22 field were made with the near-infrared camera (CISCO) attached to the Subaru Telescope. Using a narrow-band filter centered at 2.033?m, [O III] ?5007 emitters at z ~ 3.06 +/- 0.02 were searched to examine star-forming activities in an over-density region where a clustering of Lyman Break Galaxies (LBGs) and Lyman ? emitter candidates around z = 3.09 was reported, though the targeted redshift is slightly different from that of the peak of the over-density region. Although one emitter candidate at z = 3.06 was detected, it is likely to be located at a redshift of between 1 and 2 judged based on multi-band photometry. Another emission-line object was detected in another narrow-band filter (``off band'' filter) centered at 2.120 ?m, which is identified with a galaxy at z = 0.132 (the emission line is Paschen ?). The K'-band imaging data revealed the presence of 12 Extremely Red Objects (EROs) with I814-K' gep 4. The distribution of the EROs does not seem to coincide with that of Lyman Break Galaxies or Lyman alpha; emitters at z ~ 3. The magnitudes and colors of the EROs are not consistent with those of passively evolving massive elliptical galaxies at z ~ 3. Candidates for counterparts of the submm sources detected with SCUBA are found; no EROs around the submm sources are found in our magnitude limit.

Tamura, Naoyuki; Ohta, Kouji; Maihara, Toshinori; Iwamuro, Fumihide; Motohara, Kentaro; Takata, Tadafumi; Iye, Masanori

2001-08-01

36

Surgical treatment of laryngeal papillomatosis using narrow band imaging.  

PubMed

Laryngeal papillomatosis has a high rate of recurrence after surgery. Narrow band imaging (NBI) is a novel optical enhancement technology used for the diagnosis. This is the first report to date to indicate the availability of the combination of laryngomicro surgery and videoendoscopic surgery for laryngeal papillomatosis using NBI technology. The patients were a 34-year-old man and a 30-year-old man. Both patients underwent surgery in another hospital. However, due to recurrence, they were subsequently referred to the authors' department for further evaluation. The presence of papillomas was confirmed by NBI, and the papillomas were removed using an XPS Micro Debrider and a CO2 laser. Using the NBI system, the border between the normal mucosa and the papillomas could be clearly identified, allowing precise resection. Further treatment on the lesions has been carried out several times to date using NBI. The lesions have now been eradicated without further recurrence. PMID:22597574

Imaizumi, Mitsuyoshi; Okano, Wataru; Tada, Yasuhiro; Omori, Koichi

2012-09-01

37

NARROW-K-BAND OBSERVATIONS OF THE GJ 1214 SYSTEM  

SciTech Connect

GJ 1214 is a nearby M dwarf star that hosts a transiting super-Earth-size planet, making this system an excellent target for atmospheric studies. Most studies find that the transmission spectrum of GJ 1214b is flat, which favors either a high mean molecular weight or cloudy/hazy hydrogen (H) rich atmosphere model. Photometry at short wavelengths (<0.7 ?m) and in the K band can discriminate the most between these different atmosphere models for GJ 1214b, but current observations do not have sufficiently high precision. We present photometry of seven transits of GJ 1214b through a narrow K-band (2.141 ?m) filter with the Wide Field Camera on the 3.8 m United Kingdom Infrared Telescope. Our photometric precision is typically 1.7 × 10{sup –3} (for a single transit), comparable with other ground-based observations of GJ 1214b. We measure a planet-star radius ratio of 0.1158 ± 0.0013, which, along with other studies, also supports a flat transmission spectrum for GJ 1214b. Since this does not exclude a scenario where GJ 1214b has an H-rich envelope with heavy elements that are sequestered below a cloud/haze layer, we compare K-band observations with models of H{sub 2} collision-induced absorption in an atmosphere for a range of temperatures. While we find no evidence for deviation from a flat spectrum (slope s = 0.0016 ± 0.0038), an H{sub 2}-dominated upper atmosphere (<60 mbar) cannot be excluded. More precise observations at <0.7 ?m and in the K band, as well as a uniform analysis of all published data, would be useful for establishing more robust limits on atmosphere models for GJ 1214b.

Colón, Knicole D.; Gaidos, Eric, E-mail: colonk@hawaii.edu [Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

2013-10-10

38

PAU, a fully depleted mosaic imager with narrow band filters  

NASA Astrophysics Data System (ADS)

The PAU Survey studies the existence and properties of dark energy from the observations of redshift space distortions and weak lensing magnification from galaxy cross-correlations as main cosmological probes. The PAU Team is building an instrument, PAUCam, equipped with fully depleted CCD detectors, designed to be mounted at the prime focus of the 4.2 m diameter William Herschel Telescope (WHT) in La Palma. Simulations indicate that PAUCam at the WHT will be able to image about 2 square degrees per night in 40 narrow-band filters plus six wide-band filters to an AB magnitude depth of i ~ 22.5, providing low-resolution (R ~ 50) photometric spectra for around 30,000 galaxies, 5,000 stars and 1,000 quasars per square degree. Accurate photometric calibration of the PAU data is vital to achieve the survey science goals. This calibration is challenging due to the large and unusual filter set. We outline the data management pipelines being developed for the survey, both for nightly data reduction and co-addition of multiple epochs, with emphasis on the photometric calibration strategies. We also describe the main tests and results in the characterization of our Hamamatsu fully depleted detectors.

Bauer, A.; Casas, R.; Castander, F. J.; Serrano, S.

2014-03-01

39

Narrow-band injection seeding of a terahertz frequency quantum cascade laser: Selection and suppression of longitudinal modes  

NASA Astrophysics Data System (ADS)

A periodically poled lithium niobate (PPLN) crystal with multiple poling periods is used to generate tunable narrow-bandwidth THz pulses for injection seeding a quantum cascade laser (QCL). We demonstrate that longitudinal modes of the quantum cascade laser close to the gain maximum can be selected or suppressed according to the seed spectrum. The QCL emission spectra obtained by electro-optic sampling from the quantum cascade laser, in the most favorable case, shows high selectivity and amplification of the longitudinal modes that overlap the frequency of the narrow-band seed. Proper selection of the narrow-band THz seed from the PPLN crystal discretely tunes the longitudinal mode emission of the quantum cascade laser. Moreover, the THz wave build-up within the laser cavity is studied as a function of the round-trip time. When the seed frequency is outside the maximum of the gain spectrum the laser emission shifts to the preferential longitudinal mode.

Nong, Hanond; Pal, Shovon; Markmann, Sergej; Hekmat, Negar; Mohandas, Reshma A.; Dean, Paul; Li, Lianhe; Linfield, Edmund H.; Giles Davies, A.; Wieck, Andreas D.; Jukam, Nathan

2014-09-01

40

Narrow-band injection seeding of a terahertz frequency quantum cascade laser: Selection and suppression of longitudinal modes  

SciTech Connect

A periodically poled lithium niobate (PPLN) crystal with multiple poling periods is used to generate tunable narrow-bandwidth THz pulses for injection seeding a quantum cascade laser (QCL). We demonstrate that longitudinal modes of the quantum cascade laser close to the gain maximum can be selected or suppressed according to the seed spectrum. The QCL emission spectra obtained by electro-optic sampling from the quantum cascade laser, in the most favorable case, shows high selectivity and amplification of the longitudinal modes that overlap the frequency of the narrow-band seed. Proper selection of the narrow-band THz seed from the PPLN crystal discretely tunes the longitudinal mode emission of the quantum cascade laser. Moreover, the THz wave build-up within the laser cavity is studied as a function of the round-trip time. When the seed frequency is outside the maximum of the gain spectrum the laser emission shifts to the preferential longitudinal mode.

Nong, Hanond, E-mail: Nong.Hanond@rub.de; Markmann, Sergej; Hekmat, Negar; Jukam, Nathan, E-mail: Nathan.Jukam@rub.de [Arbeitsgruppe Terahertz Spektroskopie und Technologie, Ruhr-Universität Bochum, Bochum 44780 (Germany); Pal, Shovon [Arbeitsgruppe Terahertz Spektroskopie und Technologie, Ruhr-Universität Bochum, Bochum 44780 (Germany); Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum 44780 (Germany); Mohandas, Reshma A.; Dean, Paul; Li, Lianhe; Linfield, Edmund H.; Giles Davies, A. [School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Wieck, Andreas D. [Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum 44780 (Germany)

2014-09-15

41

HTS narrow band filters at UHF band for radio astronomy applications  

Microsoft Academic Search

High performance narrow-band High-Temperature Superconductor (HTS) filters at 610 MHz with very sharp cut-off response and low loss are needed for improving the observation of pulsars at the Jodrell Bank Observatory, UK. An eight-pole quasi-elliptic HTS filter using compact resonators has been designed for this purpose. The measured response of filter has an insertion loss of 0.3 dB (including a

Jiafeng Zhou; Michael J. Lancaster; Frederick Huang; Neil Roddis; Dave Glynn

2005-01-01

42

Narrow-band ultraviolet B is a useful and well-tolerated treatment for vitiligo  

Microsoft Academic Search

Background: The treatment of vitiligo remains a challenge. Objective: The purpose of this article is to review our results and experience with narrow-band ultraviolet (UV) B phototherapy for vitiligo. Methods: This is a retrospective analysis of our experience and results with patients with vitiligo who were treated with narrow-band UVB between November 1998 and November 1999. Narrow-band UVB phototherapy was

Lubomira Scherschun; Jane J. Kim; Henry W. Lim

2001-01-01

43

Whispering-Gallery-Mode Tunable Narrow-Band-Pass Filter  

NASA Technical Reports Server (NTRS)

An experimental tunable, narrow-band-pass electro-optical filter is based on a whispering-gallery resonator. This device is a prototype of tunable filters needed for the further development of reconfigurable networking wavelength-division multiplexers and communication systems that utilize radio-frequency (more specifically, microwave) subcarrier signals on optical carrier signals. The characteristics of whispering-gallery resonators that make them attractive for such applications include high tuning speed, compactness, wide tuning range, low power consumption, and compatibility with single-mode optical fibers. In addition, relative to Fabry-Perot resonators, these devices offer advantages of greater robustness and lower cost. As described in several prior NASA Tech Briefs articles, a whispering-gallery resonator is a spheroidal, disk-like, or toroidal body made of a highly transparent material. It is so named because it is designed to exploit whispering-gallery electromagnetic modes, which are waveguide modes that propagate circumferentially and are concentrated in a narrow toroidal region centered on the equatorial plane and located near the outermost edge. The experimental whispering-gallery tunable filter (see figure) is made from a disk of Z-cut LiNbO3 of 4.8-mm diameter and 0.17-mm thickness. The perimeter of the disk is rounded to a radius of curvature of 100 m. Metal coats on the flat faces of the disk serve as electrodes for exploiting the electro-optical effect in LiNbO3 for tuning. There is no metal coat on the rounded perimeter region, where the whispering-gallery modes propagate. Light is coupled from an input optical fiber into the whispering-gallery modes by means of a diamond prism. Another diamond prism is used to couple light from the whispering-gallery modes to an output optical fiber. This device is designed and operated to exploit transverse magnetic (TM) whispering- gallery modes, rather than transverse electric (TE) modes because the resonance quality factors (Q values) of the TM modes are higher. If Q values were not of major concern, it would be better to use the TE modes because the electro-optical shifts of the TE modes are 3 times those of the TM modes.

Savchenkov, Anatoliy; Iltchenko, Vladimir; Matsko, Andrey; Maleki, Lute

2004-01-01

44

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 1 Ricean K-Factors in Narrow-Band Fixed Wireless  

E-print Network

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 1 Ricean K-Factors in Narrow-Band Fixed Wireless Channels gain and Ricean K-factor. Because such fading has important implications for the design of both narrow-band a collective database from which we could construct a simple model for the probability distribution of K

Michelson, David G.

45

Narrow-band imaging system with magnifying endoscopy for superficial esophageal lesions  

Microsoft Academic Search

BackgroundBy assessing the intrapapillary capillary loop in esophageal mucosa, magnifying endoscopy can play an important role in the evaluation of superficial esophageal lesions. A newly developed narrow-band imaging system was applied to magnifying endoscopy in a clinical setting; the benefit of the narrow-band imaging system was evaluated.

Tatsuya Yoshida; Haruhiro Inoue; Shinsuke Usui; Hitoshi Satodate; Norio Fukami; Shin-ei Kudo

2004-01-01

46

47 CFR 80.1159 - Narrow-band direct-printing (NB-DP).  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Narrow-band direct-printing (NB-DP). 80.1159 Section 80... § 80.1159 Narrow-band direct-printing (NB-DP). NB-DP is a form of...the transmission and receipt of direct printing public correspondence. Ships must...

2012-10-01

47

47 CFR 80.1159 - Narrow-band direct-printing (NB-DP).  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Narrow-band direct-printing (NB-DP). 80.1159 Section 80... § 80.1159 Narrow-band direct-printing (NB-DP). NB-DP is a form of...the transmission and receipt of direct printing public correspondence. Ships must...

2010-10-01

48

47 CFR 80.1159 - Narrow-band direct-printing (NB-DP).  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Narrow-band direct-printing (NB-DP). 80.1159 Section 80... § 80.1159 Narrow-band direct-printing (NB-DP). NB-DP is a form of...the transmission and receipt of direct printing public correspondence. Ships must...

2011-10-01

49

47 CFR 80.1159 - Narrow-band direct-printing (NB-DP).  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Narrow-band direct-printing (NB-DP). 80.1159 Section 80... § 80.1159 Narrow-band direct-printing (NB-DP). NB-DP is a form of...the transmission and receipt of direct printing public correspondence. Ships must...

2013-10-01

50

47 CFR 80.461 - Narrow-band direct-printing.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Narrow-band direct-printing. 80.461 Section 80.461 Telecommunication FEDERAL...Stations Use of Telegraphy § 80.461 Narrow-band direct-printing. Subpart H of this part lists the frequencies...

2010-10-01

51

47 CFR 80.461 - Narrow-band direct-printing.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Narrow-band direct-printing. 80.461 Section 80.461 Telecommunication FEDERAL...Stations Use of Telegraphy § 80.461 Narrow-band direct-printing. Subpart H of this part lists the frequencies...

2011-10-01

52

47 CFR 80.461 - Narrow-band direct-printing.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Narrow-band direct-printing. 80.461 Section 80.461 Telecommunication FEDERAL...Stations Use of Telegraphy § 80.461 Narrow-band direct-printing. Subpart H of this part lists the frequencies...

2013-10-01

53

47 CFR 80.461 - Narrow-band direct-printing.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Narrow-band direct-printing. 80.461 Section 80.461 Telecommunication FEDERAL...Stations Use of Telegraphy § 80.461 Narrow-band direct-printing. Subpart H of this part lists the frequencies...

2012-10-01

54

Characterization of Narrow Band Filters for Infrared The Brfl and H 2 filters  

E-print Network

Characterization of Narrow Band Filters for Infrared Astronomy The Brfl and H 2 filters L. Vanzi used in Infrared Astronomy. Our study mainly quantifies the effect of temperature and tilt angle: Infrared, Narrow Band Filters, Imaging Abbreviations: IR -- Infrared; NIR -- Near infrared JEL codes: D24

Testi, Leonardo

55

Surface band-gap narrowing in quantized electron accumulation layers.  

PubMed

An energy gap between the valence and the conduction band is the defining property of a semiconductor, and the gap size plays a crucial role in the design of semiconductor devices. We show that the presence of a two-dimensional electron gas near to the surface of a semiconductor can significantly alter the size of its band gap through many-body effects caused by its high electron density, resulting in a surface band gap that is much smaller than that in the bulk. Apart from reconciling a number of disparate previous experimental findings, the results suggest an entirely new route to spatially inhomogeneous band-gap engineering. PMID:20867408

King, P D C; Veal, T D; McConville, C F; Zúñiga-Pérez, J; Muñoz-Sanjosé, V; Hopkinson, M; Rienks, E D L; Jensen, M Fuglsang; Hofmann, Ph

2010-06-25

56

Ultrafast optical control of group delay of narrow-band terahertz waves  

PubMed Central

We experimentally demonstrate control over the group delay of narrow-band (quasi continuous wave) terahertz (THz) pulses with constant amplitude based on optical switching of a metasurface characteristic. The near-field coupling between resonant modes of a complementary split ring resonator pair and a rectangular slit show an electromagnetically induced transparency-like (EIT-like) spectral shape in the reflection spectrum of a metasurface. This coupling induces group delay of a narrow-band THz pulse around the resonant frequency of the EIT-like spectrum. By irradiating the metasurface with an optical excitation pulse, the metasurface becomes mirror-like and thus the incident narrow-band THz pulse is reflected without a delay. Remarkably, if we select the appropriate excitation power, only the group delay of the narrow-band THz pulse can be switched while the amplitude is maintained before and after optical excitation. PMID:24614514

Miyamaru, Fumiaki; Morita, Hiroki; Nishiyama, Yohei; Nishida, Tsubasa; Nakanishi, Toshihiro; Kitano, Masao; Takeda, Mitsuo W.

2014-01-01

57

Narrow-Band Absorption-Enhanced Quantum Dot/J-Aggregate Conjugates  

E-print Network

We report narrow-band absorption enhancement of semiconductor nanocrystals via Förster resonance energy transfer from cyanine J-aggregates. These J-aggregated dyes associate electrostatically with short quantum-dot (QD) ...

Walker, Brian J.

58

Ultrafast optical control of group delay of narrow-band terahertz waves  

NASA Astrophysics Data System (ADS)

We experimentally demonstrate control over the group delay of narrow-band (quasi continuous wave) terahertz (THz) pulses with constant amplitude based on optical switching of a metasurface characteristic. The near-field coupling between resonant modes of a complementary split ring resonator pair and a rectangular slit show an electromagnetically induced transparency-like (EIT-like) spectral shape in the reflection spectrum of a metasurface. This coupling induces group delay of a narrow-band THz pulse around the resonant frequency of the EIT-like spectrum. By irradiating the metasurface with an optical excitation pulse, the metasurface becomes mirror-like and thus the incident narrow-band THz pulse is reflected without a delay. Remarkably, if we select the appropriate excitation power, only the group delay of the narrow-band THz pulse can be switched while the amplitude is maintained before and after optical excitation.

Miyamaru, Fumiaki; Morita, Hiroki; Nishiyama, Yohei; Nishida, Tsubasa; Nakanishi, Toshihiro; Kitano, Masao; Takeda, Mitsuo W.

2014-03-01

59

Ultrafast optical control of group delay of narrow-band terahertz waves.  

PubMed

We experimentally demonstrate control over the group delay of narrow-band (quasi continuous wave) terahertz (THz) pulses with constant amplitude based on optical switching of a metasurface characteristic. The near-field coupling between resonant modes of a complementary split ring resonator pair and a rectangular slit show an electromagnetically induced transparency-like (EIT-like) spectral shape in the reflection spectrum of a metasurface. This coupling induces group delay of a narrow-band THz pulse around the resonant frequency of the EIT-like spectrum. By irradiating the metasurface with an optical excitation pulse, the metasurface becomes mirror-like and thus the incident narrow-band THz pulse is reflected without a delay. Remarkably, if we select the appropriate excitation power, only the group delay of the narrow-band THz pulse can be switched while the amplitude is maintained before and after optical excitation. PMID:24614514

Miyamaru, Fumiaki; Morita, Hiroki; Nishiyama, Yohei; Nishida, Tsubasa; Nakanishi, Toshihiro; Kitano, Masao; Takeda, Mitsuo W

2014-01-01

60

Searching for narrow-band oscillations in solar flares in the presence of frequency-dependent noise  

NASA Astrophysics Data System (ADS)

A common feature of solar flare emission is the appearance of short timescale fluctuations, often interpreted in terms of oscillatory signatures, and often referred to as quasi-periodic pulsations (QPPs) or quasi-periodic oscilations (QPOs). These fluctuations are an important diagnostic of solar plasma, as they are linked to the flare reconnection and particle acceleration sites. However, it has recently become clear that solar flare time series, like many astrophysical objects, are often dominated by frequency-dependent 'red' noise, rather than white noise. This frequency-dependent red-noise is commonly not taken into account when analyzing flare time-series for narrow-band oscillations. We demonstrate the application of a Bayesian method of searching for narrow-band oscillations in flares (based on Vaughan 2010) that fully accounts for frequency-dependent noise. We apply this method to the recent flares of 2011 February 15 and 2011 June 7, utilizing high-cadence EUV and X-ray data from the Proba-2/LYRA and Fermi/GBM instruments. While emphasizing that the observed fluctuations are a very real effect, we show that the emission from the selected events can be well described by a frequency-dependent noise model, without the need to invoke an explicit oscillatory mechanism. This presents a challenge to our current understanding of flare fluctuations, and suggests that narrow-band oscillations in flare emission may be much less prevalent than previously believed.

Inglis, Andrew; Ireland, Jack

2014-06-01

61

Narrow-band EUV Multilayer Coating for the MOSES Sounding Rocket  

NASA Technical Reports Server (NTRS)

The Multi-order Solar EUV Spectrograph (MOSES) is a slitless spectrograph designed to study solar He II emission at 303.8 Angstroms, to be launched on a sounding rocket payload. One difference between MOSES and other slitless spectrographs is that the images are recorded simultaneously at three spectral orders, m = -1,0, +l. Another is the addition of a narrow-band multilayer coating on both the grating and the fold flat, which will reject out-of-band lines that normally contaminate the image of a slitless instrument. The primary metrics f a the mating were high peak reflectivity and suppression of Fe XV and XVI emission lines at 284 Angstroms and 335 Angstroms, respectively. We chose B4C/Mg2Si for our material combination since it provides better values for all three metrics together than the other leading candidates Si/Ir, Si/B4C or Si/SiC. Measurements of witness flats at NIST indicate the peak reflectivity at 303.6 is 38.5% for a 15 bilayer stack, while the suppression at 284 Angstroms, is 4.5x and at 335 Angstroms is 18.3x for each of two reflections in the instrument. We present the results of coating the MOSES flight gratings and fold flat, including the spectral response of the fold flat and grating as measured at NIST's SURF III and Brookhaven's X24C beamline.

Owens, Scott M.; Gum, Jeffery S.; Tarrio, Charles; Dvorak, Joseph; Kjornrattanawanich, Benjawan; Keski-Kuha, Ritva; Thomas, Roger J.; Kankelborg, Charles C.

2005-01-01

62

47 CFR 80.361 - Frequencies for narrow-band direct-printing (NBDP), radioprinter and data transmissions.  

Code of Federal Regulations, 2012 CFR

...Frequencies for narrow-band direct-printing (NBDP), radioprinter and data transmissions...Frequencies for narrow-band direct-printing (NBDP), radioprinter and data transmissions...coast stations for narrow-band direct-printing (NBDP) and data transmissions....

2012-10-01

63

47 CFR 80.361 - Frequencies for narrow-band direct-printing (NBDP), radioprinter and data transmissions.  

Code of Federal Regulations, 2011 CFR

...Frequencies for narrow-band direct-printing (NBDP), radioprinter and data transmissions...Frequencies for narrow-band direct-printing (NBDP), radioprinter and data transmissions...coast stations for narrow-band direct-printing (NBDP) and data transmissions....

2011-10-01

64

47 CFR 80.361 - Frequencies for narrow-band direct-printing (NBDP), radioprinter and data transmissions.  

Code of Federal Regulations, 2013 CFR

...Frequencies for narrow-band direct-printing (NBDP), radioprinter and data transmissions...Frequencies for narrow-band direct-printing (NBDP), radioprinter and data transmissions...coast stations for narrow-band direct-printing (NBDP) and data transmissions....

2013-10-01

65

Analytic design of optimal FIR narrow-band filters using Zolotarev polynomials  

NASA Astrophysics Data System (ADS)

An analytic method for designing narrow-band FIR filters using Zolotarev polynomials, which are extensions of Chebyshev polynomials, is proposed. These filters are optimal in the Chebyshev sense. Bandpass and bandstop narrow-band filters, as well as low-pass and high-pass filters, can be designed by this method. The design procedure and related formulas are presented. Design examples are included to show the properties of these filters.

Chen, Xiangkun; Parks, Thomas W.

1986-11-01

66

Characterization of microwave magnetic narrow band filters by ferromagnetic resonance  

NASA Astrophysics Data System (ADS)

Ferromagnetic resonance cavity and microstrip excitation experiments have been performed on a straight edge yttrium iron garnet resonator. Both excitation systems have been modeled as band-stop configurations and a mapping from the swept bias magnetic field domain to the frequency domain has been elaborated to compare them in terms of the dispersion and the amplitude of the magnetostatic wave modes.

Bousbahi, Khaled; Marcelli, Romolo

2000-05-01

67

Some advantages of wide over narrow band signals in the search for extraterrestrial intelligence \\/SETI  

Microsoft Academic Search

The present interest in the search for narrow-band signals in connection with SETI as well as its reasons and implications are considered. As an alternative, and considering the advantages of spread spectrum techniques in terms of higher communications capacity, the use of a wide-band transmission strategy is examined. The effects of dispersion by the interstellar medium and its use for

P. F. Clancy

1980-01-01

68

Tracking photosynthetic efficiency with narrow-band spectroradiometry  

NASA Technical Reports Server (NTRS)

Narrow-waveband spectroradiometry presents the possibility of detecting subtle signals closely related to the current physiological state of vegetation. One such signal related to the epoxidation state of the xanthophyll cycle pigments, violaxanthin, antheraxanthin, and zeaxanthin is discussed. Recent advances in plant ecophysiology demonstrated a close relationship between these pigments and the regulatory state of photosystem 2 in photosynthesis. Our recent field studies of sunflower (Helianthus annuus) and oak (Quercus agrifolia) demonstrated that a 'xanthophyll signal' can be isolated from the diurnal reflectance spectra of intact canopies. Furthermore, the xanthophyll signal can be used to derive a 'physiological reflectance index' (PRI) that closely correlates with the actual photosynthetic efficiency (defined as the photosynthetic rate divided by the incident PAR) in closed canopies. If these signals were detectable in Airborne Visible/Infrared Imaging Spectrometers (AVIRIS) images, they could lead to improved remote estimates of photosynthetic fluxes.

Gamon, John A.; Field, Christopher B.

1992-01-01

69

Pilot-aided modulation for narrow-band satellite communications  

NASA Technical Reports Server (NTRS)

This paper discusses a number of tone-aided modulation techniques which have been studied as part of the Mobile Satellite Experiment (MSAT-X) Program. In all instances tone(s) are inserted into data-free portions of the transmit spectrum and used by the receiver to sense the amplitude and frequency/phase distortions introduced by the channel. The receiver then uses this information in a feedforward manner to lessen the effect of the distortions on the data detection performance. Particular techniques discussed are the Tone Calibration Technique (TCT), the Dual Tone Calibrated Technique (DTCT), Transparent Tone-In-Band (TTIB), and Dual-Tone Single Sideband (DTSSB).

Saulnier, Gary J.; Rafferty, William

1988-01-01

70

Photodegradation of polycarbonate under narrow band irradiation at 172 nm  

NASA Astrophysics Data System (ADS)

Photostability of polymers is an important issue since most polymers tend to loose their original properties upon exposure to light, especially to ultraviolet radiation. Polycarbonates are widely used industrial materials because of their excellent properties, which includes transparency, high tensile strength, impact resistance and rigidity. In this paper, we present results on 172 nm photodegradation of polycarbonate (PC) films. PC films of 50 ?m thickness were irradiated for up to 20 min using a Xe2? excimer lamp system. Ex situ UV visible spectroscopic investigation of the treated films revealed the appearance of two strong absorption bands at 279 and 317 nm and a third broad band centred around 380 nm whose intensity increased linearly with illumination time. The morphological changes were characterised by atomic force microscopy and resulted in a gradually increasing roughness, being a linear function of irradiation time. The interpretation of the observed chemical degradation is based on attenuated total reflection IR and X-ray photoelectron spectroscopic measurements which show cleavage of the aromatic C-C and carboxylic CO-O bonds together with some nitrogen incorporation into the surface layer of the irradiated films.

Geretovszky, Zs.; Hopp, B.; Bertóti, I.; Boyd, I. W.

2002-01-01

71

The relationship between rape biomass and narrow-band vegetation indices  

NASA Astrophysics Data System (ADS)

The Relationships between rape biomass and hyperspectral vegetation indices are investigated in this paper. The data for this study comes from field hyperspectral reflectance measurements of rape during 2002-2003 growing period. Reflectance was measured in discrete narrow bands between 350 and 2500 nm. Observed rape biomass included wet biomass (WBM including leaf wet biomass-LWBM, stem wet biomass-SWBM, fruit wet biomass-FWBM), and dry biomass(DBM: including leaf dry biomass-LDBM, stem dry biomass, fruit dry biomass-FDBM). Narrow band normalized difference vegetation index (NBNDVI) and narrow band ratio vegetation index (NBRVI)involving all possible two-band combinations of discrete channels was tested. Special narrow band lambda (?1) versus lambda (?2) plots of R2 values illustrate the most effective wavelength combinations (?1 and ?2) and band-width (??1 and ??2) for predicting rape biomass at different development stage. A strong relationship with rape biomass is located in red-edge, the longer portion of red, moisture-sensitive NIR, longer portion of the blue band, the intermediate portion of SWIR, and the longer portion of SWIR.

Huang, Jingfeng; Wang, Yuan; Wang, Fumin; Wang, Xiuzhen

2004-11-01

72

Narrow-band processing and fusion approach for explosive hazard detection in FLGPR  

NASA Astrophysics Data System (ADS)

This paper proposes an effective anomaly detection algorithm for a forward-looking ground-penetrating radar(FLGPR). One challenge for threat detection using FLGPR is its high dynamic range in response to different kinds of targets and clutter objects. The application of a fixed threshold for detection in a full-band radar image often yields a large number of false alarms. We propose a method that uses both narrow-band and full-band radar processing, coupled with a classifier that uses complex-valued Gabor filter responses as the features. We then fuse the narrow-band and fullband images into a composite confidence map and detect local maxima in this map to produce candidate alarm locations. Full-band radar images provide a high degree of image resolution, while narrow-band images provide a means to detect targets which have a unique narrow-band signature. Experimental results for our improved detection techniques are demonstrated on data sets collected at a US Army test site.

Havens, Timothy C.; Keller, James M.; Ho, K. C.; Ton, Tuan T.; Wong, David C.; Soumekh, Mehrdad

2011-06-01

73

Generation of narrow-band terahertz coherent Cherenkov radiation in a dielectric wakefield structure  

NASA Astrophysics Data System (ADS)

This study explores the use of a dielectric-lined waveguide structure as a means of producing narrow-band terahertz radiation in the form of electron-beam-driven coherent Cherenkov radiation wakefields. This concept builds on previously studied scenarios such as the Cherenkov maser and the Cherenkov free-electron laser. It is distinct in that it relies solely on coherent wakefield excitation instead of a microbunching instability gain process, in analogy to the superradiant regime of FEL operation. The narrow bandwidth is due to the single-mode nature of the excitation, enabled by the exclusion (due to coherence) of discrete waveguide modes with wavelengths shorter than the driving electron bunch length. This allows an inherently broadband beam current profile to radiate power into a single frequency, which is selectable by appropriate choice of design parameters. The theoretical component of this dissertation is aimed at making predictions for comparison with experimental results. The functional form and propagating mode frequencies of the electromagnetic fields in the waveguide structure are found by eigenmode solution in the source-free case beginning from Maxwell's equations; the response of the structure to a driving electron bunch is then found using a wakefield formalism. Predictions for the frequencies and radiated energy levels obtained from this analysis are corroborated computationally using the commercial particle-in-cell simulation code OOPIC PRO. The experiment is designed to be a proof-of-principle demonstration of the effectiveness of this scenario in converting the energy in an electron beam into electromagnetic radiation. We present detailed measurements showing a narrow emission spectrum peaked at 367 +/- 3 GHz from a 1 cm long fused silica capillary tube with sub-mm transverse dimensions, matching the predicted (analytical and computational) TM01 mode resonance to within 1% error. This measurement confirms the expected preferential coherent excitation of the TM01 mode over the HEM11 mode, which lies nearby in frequency but still decisively outside the error estimate established over multiple measurements. The measured 3 dB bandwidth is on the order of ? 10% and is seen to be transform-limited. We observe a 100 GHz shift in the emitted central frequency when the tube wall thickness is changed by 50 mum, demonstrating the modular tunability of the source. Calibrated measurements of the radiated energy register up to 10 muJ per 60-80 ps pulse for an incident sub-picosecond electron beam carrying 200 pC of charge, corresponding to a peak power of approximately 150 kW. A case study considering the implementation of this scenario using a 10-cm-long structure with smaller transverse dimensions indicates a possible yield of 50 MW peak power at 1.8 THz and 0.1% bandwidth. This dissertation reports the first direct measurements of narrow-band THz coherent Cherenkov radiation driven by a sub-picosecond electron beam in a dielectric wakefield structure, representing a successful adaptation of the previously proven Cherenkov FEL concept to the realm of ultra-short electron beams such as are available in state-of-the-art user facilities around the world. These results prove the potential of this method to produce tunable, narrow-band, pulse-length-variable, multi-megawatt peak-power radiation at f > 1 THz in existing modern electron accelerators.

Cook, Alan Matthew

74

Cyclotron side band emissions from magnetospheric electrons  

NASA Technical Reports Server (NTRS)

Very low frequency emissions with subharmonic cyclotron frequency from magnetospheric electrons were detected by the S(3)-A satellite (Explorer 45) whose orbit is close to the magnetic equatorial plane where the wave-particle interaction is most efficient. These emissions were observed during the main phase of a geomagnetic storm in the nightside of the magnetosphere outside of the plasmasphere. During the event of these side-band emissions, the pitch angle distributions of high energy electrons (greater than 50 keV) and of energetic protons (greater than 100 keV) showed remarkable changes with time, whereas those of low energy electrons and protons remained approximately isotropic. In this type of event, emissions consist essentially of two bands, the one below the equatorial electron gyrofrequency, and the other above. The emissions below are whistler mode, and the emissions above are electrostatic mode.

Maeda, K.

1975-01-01

75

Elementary Excitations in Ferromagnetic Semiconductor Superlattice in the Narrow-band Limit  

NASA Astrophysics Data System (ADS)

The transfer matrix method, developed in our previous paper [1], is used to study bulk and surface magnetic excitations of a semi-infinite ferromagnetic semiconductor (FMS's) superlattice. Results are discussed in the narrow-band limit. The spin-wave frequencies for a semi-infinite narrow-band semiconductor are analyzed in the low-frequency, as well as in the high-frequency region. In the frame of the same methodology, bulk and surface magnetic excitations of thin FMS's films are analyzed in dependence of the parameters of the system. Results are analyzed numerically, discussed and plotted.

Pavkov-Hrvojevi?, M.; Panti?, M.; Radoševi?, S.; Rutonjski, M.; Škrinjar, M.; Kapor, D.

2010-01-01

76

Differential-phase-shift quantum key distribution using heralded narrow-band single photons.  

PubMed

We demonstrate the first proof of principle differential phase shift (DPS) quantum key distribution (QKD) using narrow-band heralded single photons with amplitude-phase modulations. In the 3-pulse case, we obtain a quantum bit error rate (QBER) as low as 3.06% which meets the unconditional security requirement. As we increase the pulse number up to 15, the key creation efficiency approaches 93.4%, but with a cost of increasing the QBER. Our result suggests that narrow-band single photons maybe a promising source for the DPS-QKD protocol. PMID:23609661

Liu, Chang; Zhang, Shanchao; Zhao, Luwei; Chen, Peng; Fung, C-H F; Chau, H F; Loy, M M T; Du, Shengwang

2013-04-22

77

Motional narrowing and ergodic bands in excited superdeformed states of {sup 194}Hg.  

SciTech Connect

The E{sub {gamma}}-E{sub {gamma}} coincidence spectra from the electromagnetic decay of excited superdeformed states in {sup 194}Hg reveal surprisingly narrow ridges, parallel to the diagonal. A total of 100-150 excited bands are found to contribute to these ridges, which account for nearly all the unresolved E2 decay strength. Comparison with theory suggests that these excited bands have many components in their wave functions, yet they display remarkable rotational coherence. This phenomenon can be explained in terms of the combination of shell effects and motional narrowing.

Lopez-Martens, A.; Dossing, T.; Khoo, T. L.; Matsuo, M.; Herskind, B.; Lauritsen, T.; Carpenter, M. P.; Janssens, R. V. F.; Hackman, G.; Lee, I-Y.; Macchiavelli, A. O.; Vigezzi, E.; Yoshida, K.; C.S.N.S.M.; Niels Bohr Inst.; Niigata Univ.; LBNL; Univ. di Milano; Nara Univ.

2008-03-14

78

Application of narrow-band television to industrial and commercial communications  

NASA Technical Reports Server (NTRS)

The development of narrow-band systems for use in space systems is presented. Applications of the technology to future spacecraft requirements are discussed along with narrow-band television's influence in stimulating development within the industry. The transferral of the technology into industrial and commercial communications is described. Major areas included are: (1) medicine; (2) education; (3) remote sensing for traffic control; and (5) weather observation. Applications in data processing, image enhancement, and information retrieval are provided by the combination of the TV camera and the computer.

Embrey, B. C., Jr.; Southworth, G. R.

1974-01-01

79

Hydrogen-Saturated Saline Protects Intensive Narrow Band Noise-Induced Hearing Loss in Guinea Pigs through an Antioxidant Effect  

PubMed Central

The purpose of the current study was to evaluate hydrogen-saturated saline protecting intensive narrow band noise-induced hearing loss. Guinea pigs were divided into three groups: hydrogen-saturated saline; normal saline; and control. For saline administration, the guinea pigs were given daily abdominal injections (1 ml/100 g) 3 days before and 1 h before narrow band noise exposure (2.5–3.5 kHz 130 dB SPL, 1 h). The guinea pigs in the control group received no treatment. The hearing function was assessed by the auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) recording. The changes of free radicals in the cochlea before noise exposure, and immediately and 7 days after noise exposure were also examined. By Scanning electron microscopy and succinate dehydrogenase staining, we found that pre-treatment with hydrogen-saturated saline significantly reduced noise-induced hair cell damage and hearing loss. We also found that the malondialdehyde, lipid peroxidation, and hydroxyl levels were significantly lower in the hydrogen-saturated saline group after noise trauma, indicating that hydrogen-saturated saline can decrease the amount of harmful free radicals caused by noise trauma. Our findings suggest that hydrogen-saturated saline is effective in preventing intensive narrow band noise-induced hearing loss through the antioxidant effect. PMID:24945316

Chen, Liwei; Yu, Ning; Lu, Yan; Wu, Longjun; Chen, Daishi; Guo, Weiwei; Zhao, Lidong; Liu, Mingbo; Yang, Shiming; Sun, Xuejun; Zhai, Suoqiang

2014-01-01

80

An Interpretation of Banded Magnetospheric Radio Emissions  

NASA Technical Reports Server (NTRS)

Recently-published Active Magnetospheric Particle Tracer Explorer/Isothermal Remanent Magnetization (AMPTE/IRM) banded magnetospheric emissions, commonly referred to as '(n + 1/2)f(sub ce)' emissions where f(sub ce) is the electron gyrofrequency, are analyzed by treating them as analogous to sounder-stimulated ionospheric emissions. We show that both individual AMPTE/IRM spectra of magnetospheric banded emissions, and a statistically-derived spectra observed over the two-year lifetime of the mission, can be interpreted in a self-consistent manner. The analysis, which predicts all spectral peaks within 4% of the observed peaks, interprets the higher-frequency emissions as due to low group-velocity Bernstein-mode waves and the lower-frequency emissions as eigen modes of cylindrical-electromagnetic-plasma-oscillations. The demarcation between these two classes of emissions is the electron plasma frequency f(sub pe), where an emission is often observed. This f(sub pe), emission is not necessarily the strongest. None of the observed banded emissions were attributed to the upper-hybrid frequency. We present Alouette-2 and ISIS-1 plasma-resonance data, and model electron temperature (T(sub e)) values, to support the argument that the frequency-spectrum of ionospheric sounder-stimulated emissions is not strongly temperature dependent and thus that the interpretation of these emissions in the ionosphere is relevant to other plasmas (such as the magnetosphere) where N(sub e) and T(sub e) can be quite different but where the ratio f(sub pe)/f(sub ce) is identical.

Benson, Robert F.; Osherovich, V. A.; Fainberg, J.; Vinas, A. F.; Ruppert, D. R.; Vondrak, Richard R. (Technical Monitor)

2000-01-01

81

Spatially localized band-gap renormalization and band-filling effects in three growth-interrupted multiple asymmetric coupled narrow quantum wells  

NASA Astrophysics Data System (ADS)

For the first time to our knowledge, we have observed a large excitonic linewidth broadening at low temperatures in three growth-interrupted asymmetric coupled GaAs/Al0.3Ga0.7As narrow quantum wells as the irradiance increases. We attribute this broadening to the decrease of the exciton binding energy that results from spatially localized band-gap renormalization. We also observed the stepwise saturation of the photoluminescence emission peaks as irradiance increases. We attribute this saturation to the result of spatially localized band filling. Based on time-resolved photoluminescence measurements, we have determined the nature of the recombination processes. We have also determined the exciton densities. In both undoped and modulation-doped samples, the small interface island area that results from growth interruption allows us to generate a large carrier density in the islands; both band-gap renormalization and band-filling effects become stronger even at low irradiances. When the temperature is higher than the transition temperature, the free-carrier recombination dominates the photoluminescence spectrum. The band-gap renormalization then results in a red shift of the photoluminescence emissions.

Cui, A. G.; Ding, Y. J.; Lee, S. J.; Veliadis, J. V. D.; Khurgin, Jacob B.; Li, S.; Reynolds, D. C.; Grata, J.

1996-03-01

82

Analysis of discrimination techniques for low-cost narrow-band spectrofluorometers.  

PubMed

The need for covering large areas in oceanographic measurement campaigns and the general interest in reducing the observational costs open the necessity to develop new strategies towards this objective, fundamental to deal with current and future research projects. In this respect, the development of low-cost instruments becomes a key factor, but optimal signal-processing techniques must be used to balance their measurements with those obtained from accurate but expensive instruments. In this paper, a complete signal-processing chain to process the fluorescence spectra of marine organisms for taxonomic discrimination is proposed. It has been designed to deal with noisy, narrow-band and low-resolution data obtained from low-cost sensors or instruments and to optimize its computational cost, and it consists of four separated blocks that denoise, normalize, transform and classify the samples. For each block, several techniques are tested and compared to find the best combination that optimizes the classification of the samples. The signal processing has been focused on the Chlorophyll-a fluorescence peak, since it presents the highest emission levels and it can be measured with sensors presenting poor sensitivity and signal-to-noise ratios. The whole methodology has been successfully validated by means of the fluorescence spectra emitted by five different cultures. PMID:25558997

Aymerich, Ismael F; Sánchez, Albert-Miquel; Pérez, Sergio; Piera, Jaume

2014-01-01

83

Monte Carlo Simulation of Radiation in Gases with a NarrowBand Model  

E-print Network

Monte Carlo Simulation of Radiation in Gases with a Narrow­Band Model and a Net, Germany. published in ASME Journal of Heat Transfer, May 1996, pp.401­407 Abstract The Monte Carlo method with the Monte Carlo method : numerical efficiency becomes independent of optical thickness, strongly non uniform

Dufresne, Jean-Louis

84

Treatment of generalized vitiligo in children with narrow-band (TL01) UVB radiation therapy  

Microsoft Academic Search

Background: Only a few clinical trials have been performed on the treatment of generalized vitiligo in children. Recently, narrow-band UVB therapy has been reported to be an effective and safe therapeutic option in adult patients with vitiligo. Objective: We studied the efficacy and safety of UVB (311 nm) therapy in children with generalized vitiligo and evaluated the effect of the

M. D. Njoo; J. D. Bos; W. Westerhof

2000-01-01

85

Integrable narrow-band model with possible relevance to heavy-fermion systems  

Microsoft Academic Search

A lattice model consisting of a single narrow band is introduced to describe some aspects of heavy electrons. The model excludes double occupancy of the sites and electrons on nearest-neighbor sites interact via a charge interaction and spin exchange. The model is integrable in one dimension for some special values of the coupling constants. These cases are related to the

P. Schlottmann

1987-01-01

86

Search for neutrino oscillations at the AGS with the narrow band beam  

SciTech Connect

We have taken neutrino data with the Narrow Band Beam (NBB) at Brookhaven National Laboratory (BNL) in the summer and fall of 1985. We are in the process of completing the analysis of the NBB data. In this paper we present preliminary results of this analysis. We observe an anomalous appearance of electron neutrinos above the expected background. 3 refs., 16 figs., 3 tabs.

Chi, C.; Kondakis, N.; Lee, W.; O'Brien, E.; O'Halloran, T.; Reardon, K.; Salman, S.; Blumenfeld, B.; Chichura, L.; Chien, C.Y.

1987-01-01

87

Rejection of Narrow Band Unknown Disturbances in an Active Suspension System  

E-print Network

Constantinescu, Daniel Rey and Ioan Dor´e Landau Abstract-- The rejection of unknown disturbances of un- known of unknown narrow band disturbances, with the model of the plant considered known (e.g. obtained by standard of the active suspension system considers that the plant model is known and the disturbance model is unknown2

Boyer, Edmond

88

Narrow circumstellar emission lines in SN 1987A  

NASA Technical Reports Server (NTRS)

Low and high dispersion short wavelength prime (SWP) spectra of SN 1987A show that the supernova's progenitor was in a post red giant branch stage of evolution at the time of its demise in February 1987. The development of narrow high temperature emission lines of N 5, N 4, N 3, C 3, He 2 and O 3 were followed since May 1987. Observations through April 1990 are presented. The lines are interpreted as arising in a low density gas surrounding the supernova which was photoionized by the extreme UV pulse at shock breakout. In this picture, their temporal evolution is determined primarily by light travel time effects and recombination. Comparison of models of circumstellar environment with the International Ultraviolet Explorer (IUE) observations are discussed.

Sonneborn, George; Cassatella, Angelo; Wamsteker, Willem; Fransson, Claes; Kirshner, Robert; Gilmozzi, Roberto; Panagia, Nino

1990-01-01

89

Experimental analysis of emission linewidth narrowing in a pulsed KGd(WO ?) ? Raman laser.  

PubMed

The linewidth of a KGd(WO ?) ? (KGW) intracavity pumped Raman laser is analyzed experimentally for different configurations of the Raman and pump laser resonators: with narrow and broadband pump emission profiles, with and without linewidth narrowing elements in the Raman laser resonator, with and without injection seeding into the Raman cavity. The benefits of a narrow linewidth pump source in combination with linewidth narrowing elements in the Raman laser cavity for the efficient linewidth narrowing of the Raman laser emission are explained. 20 kW peak-power pulses at 1156 nm with 0.43 cm?¹ emission linewidth are demonstrated from an injection seeded KGW Raman laser. PMID:25321552

Savitski, Vasili G

2014-09-01

90

Manipulating stimulated coherent anti-Stokes Raman spectroscopy signals by broad-band and narrow-band pulses  

PubMed Central

A transition-amplitude based representation of heterodyne detected coherent anti-Stokes Raman signals is used to separate them into a parametric component that involves no change in the material and dissipative processes associated with various transitions between states. Qualitatively different contributions from the two processes are predicted for the signal generated by an overlapping narrow (picosecond) and broad-band (femtosecond) pulse. PMID:19929063

Rahav, Saar; Roslyak, Oleksiy; Mukamel, Shaul

2009-01-01

91

Variable doping narrow-band response GaAlAs photocathode the preparation method of the research  

NASA Astrophysics Data System (ADS)

In order to avoid the low sensitivity common problem of 532nm sensitive narrow-band response photocathode, variable doping narrow-band response GaAlAs photocathode structure is designed. The photocathode is composed of GaAs substrates, Ga1-x1Alx1As buffer layer, Ga1-x2Alx2As doping concentration gradient emissive layer and GaAs protection layer from bottom to top. Among them, exponential doping method is applied to Ga1-x2Alx2As unit layer from the bottom to the top. And a preparation methods of GaAlAs photocathode is developed. For the GaAlAs photocathode components which grow well, chemical cleaning, heating purification and (Cs, O) activation are operated, and ultimately Cs / O activation layer is formed on the surface of Ga1-x2Alx2As doping concentration gradient emissive layer. The highest sensitivity of the photocathode peak response is at 532nm, and the photocathode quantum efficiency in 532nm peaks at 36%.

Xu, Yuan; Chen, XinLong; Zhao, Jing; Wang, Honggang; Chang, BenKang

2012-11-01

92

A narrow-band search for extraterrestrial intelligence (SETI) using the interstellar contact channel hypothesis  

Microsoft Academic Search

A search is reported for narrow spectral line emission from 176 targets (including 166 stars and seven globular clusers) at the hypothesized 'interstellar communications channel' frequency of 4.462336275 GHz (= pi times the neutral hydrogen line at 1.42 GHz) using the Parkes Radio telescope. The frequency was Doppler corrected for the solar barycenter, target barycenter, and cosmic microwave background (CMB)

D. G. Blair; R. P. Norris; E. R. Troup; R. Twardy; K. J. Wellington; A. J. Williams; A. E. Wright; M. G. Zadnik

1992-01-01

93

47 CFR 80.219 - Special requirements for narrow-band direct-printing (NB-DP) equipment.  

Code of Federal Regulations, 2010 CFR

...requirements for narrow-band direct-printing (NB-DP) equipment. 80.219 ...requirements for narrow-band direct-printing (NB-DP) equipment. NB-DP...Recommendation M.476-5, “Direct-Printing Telegraph Equipment in the Maritime...

2010-10-01

94

47 CFR 80.219 - Special requirements for narrow-band direct-printing (NB-DP) equipment.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Special requirements for narrow-band direct-printing (NB-DP) equipment. 80.219 Section 80.219 Telecommunication...80.219 Special requirements for narrow-band direct-printing (NB-DP) equipment. NB-DP and data...

2013-10-01

95

47 CFR 80.219 - Special requirements for narrow-band direct-printing (NB-DP) equipment.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Special requirements for narrow-band direct-printing (NB-DP) equipment. 80.219 Section 80.219 Telecommunication...80.219 Special requirements for narrow-band direct-printing (NB-DP) equipment. NB-DP and data...

2012-10-01

96

47 CFR 80.219 - Special requirements for narrow-band direct-printing (NB-DP) equipment.  

Code of Federal Regulations, 2011 CFR

...requirements for narrow-band direct-printing (NB-DP) equipment. 80.219 ...requirements for narrow-band direct-printing (NB-DP) equipment. NB-DP...Recommendation M.476-5, “Direct-Printing Telegraph Equipment in the Maritime...

2011-10-01

97

A theory for narrow-banded radio bursts at Uranus - MHD surface waves as an energy driver  

NASA Technical Reports Server (NTRS)

A possible scenario for the generation of the narrow-banded radio bursts detected at Uranus by the Voyager 2 planetary radio astronomy experiment is described. In order to account for the emission burstiness which occurs on time scales of hundreds of milliseconds, it is proposed that ULF magnetic surface turbulence generated at the frontside magnetopause propagates down the open/closed field line boundary and mode-converts to kinetic Alfven waves (KAW) deep within the polar cusp. The oscillating KAW potentials then drive a transient electron stream that creates the bursty radio emission. To substantiate these ideas, Voyager 2 magnetometer measurements of enhanced ULF magnetic activity at the frontside magnetopause are shown. It is demonstrated analytically that such magnetic turbulence should mode-convert deep in the cusp at a radial distance of 3 RU.

Farrell, W. M.; Curtis, S. A.; Desch, M. D.; Lepping, R. P.

1992-01-01

98

On a Hydrodynamic Source of Self-Excitation of Narrow-Band Disturbances in a Wind Tunnel  

NASA Astrophysics Data System (ADS)

A study has been made of the occurrence of intense narrow-band components in the spectra of pressure pulsations in a wind tunnel. It has been established that the high level of acoustic emission in auto-oscillations is a consequence of negative static-pressure gradients inside the nozzle and the change in the regime of wall shear flow of an incompressible medium, of the formation of large-scale coherent structures, and of resonance phenomena. It has been noted that the azimuthally nonuniform topology of large-scale transient-flow structures emitting sound and implementation of not a single resonance are responsible for the existence of ensembles of components of an undesirably high level in the pressure-pulsation spectra in the tunnel. One possible method of fighting the considered sound emission generating auto-oscillations has been indicated.

Karavosov, R. K.; Prozorov, A. G.

2014-11-01

99

Narrow Band Ratio Vegetation Indices and Itsrelationships With Rice Agronomic Variables  

NASA Astrophysics Data System (ADS)

The present study aims to determine spectral bands that are best suited for characterizing rice agronomic variables. The data for this study came from ground-level hyperspectral reflectance measurements of rice at different stage. Reflectance was measured in discrete narrow bands between 350 and 2500 nm. Observed rice agronomic variables included leaf area index (LAI), wet biomass (WBM including aboveground wet biomass-AGWBM, leaf wet biomass-LWBM, stem wet biomass-SWBM), and dry biomass(DBM: including aboveground dry biomass-AGDBM, leaf dry biomass-LDBM, stem dry biomass.) Firstly, narrow band ratio vegetation index (NBRVI) involving all possible two bands combinations of discrete channels were tested. The second part of the paper describes a rigorous search procedure to identify the best NBRVI predictors of rice agronomic variables. Special narrow band lambda (?1) versus lambda (?2) plots of R2 values illustrates the most effective wavelength combinations (?1 and ?2) and band-widths (??1 and ??2) for predicting rice agronomic variables at different development stages. The best of the NBRVI models explained 58% to 83% variability rice agronomic variables at different development stage. A strong relationship with rice agronomic variables is located in red-edge, 700 nm to 750 nm, the longer portion of red (650nm to 700nm), the shorter portion of green (500nm to 550nm), a particular portion of NIR (800nm to 850nm). They are followed by moisture-sensitive NIR(1150nm to 1200nm), and two portions of SWIR (1600nm to 1650nm).

Wang, Fumin; Huang, Jingfeng

100

Narrow Band Region-Based Active Contours Model for Noisy Color Image Segmentation  

PubMed Central

A narrow band active contour model for color image segmentation is proposed, which applies local statistics to improve the robustness against noise. The crux of our approach is to use intensity mean of local region to define the force function within a level set framework, within which a narrow band is implemented to further improve the computational efficiency. In addition, the image is segmented from channel-to-channel, which shows superior performance when the intensities of the object and background are similar. Furthermore, a multichannel segmentation combination method is used to integrate the information of multiple level sets. The proposed model has been applied to both synthetic and real images with expected results, and the comparison with the state-of-the-art approaches demonstrates the accuracy and superiority of our approach. PMID:25121116

Xie, Xiaomin; Zhang, Aijun; Wang, Changming; Meng, Xiangfei

2014-01-01

101

Defining the endoscopic appearances of tylosis using conventional and narrow-band imaging: a case series.  

PubMed

Tylosis is an autosomal dominant skin disorder strongly associated with esophageal squamous cell cancer. We present a single-operator experience of utilizing conventional endoscopy and narrow-band imaging with magnification to characterize esophageal appearances in tylosis. Nineteen consecutive patients with tylosis attending for surveillance endoscopy were studied. White-light imaging (WLI) and narrow-band imaging (NBI) were undertaken, with magnification being performed as necessary. On WLI, we classified 12 patients as having mild change, 5 moderate change, and 2 severe change. WLI can define changes to the esophageal mucosa of variable hyperkeratosis and identify more significant focal abnormalities. NBI enhances these mucosal changes, and NBI with magnification can demonstrate intrapapillary capillary loop changes compatible with dysplasia, prompting consideration of surgery. This report is the first to characterize the endoscopic appearances in tylosis. PMID:21623561

Smart, H; Kia, R; Subramanian, S; Khalid, S; Campbell, F; Ellis, A

2011-08-01

102

Narrow-band-noise generation in charge-density-wave compounds  

NASA Astrophysics Data System (ADS)

The absolute magnitude of the narrow-band noise is estimated within the framework of the Fukuyama-Lee-Rice model. The noise is predicted to vary with sample volume scrV as scrV-1/2, as has been previously noted, and with impurity concentration ni as n1/2i. Experiments on the sliding charge-density wave in NbSe3 agree with both of these predictions. The predicted magnitude differs from that observed in NbSe3, but it is in quantitative agreement with data for the charge-density waves in K0.3MoO3 and (TaSe4)2I. These results provide additional evidence both for bulk narrow-band-noise generation and for weak pinning.

Dicarlo, D.; McCarten, J.; Adelman, T. L.; Maher, M. P.; Thorne, R. E.

1994-05-01

103

Dual-Band Stimulated Parametric Emission Microscopy  

NASA Astrophysics Data System (ADS)

We demonstrate that two distinct images can be simultaneously acquired using the dual-band configuration of stimulated parametric emission (SPE) microscopy, which is based on the four-wave mixing process enhanced by two-photon electronic resonance. The dual-band SPE microscopy utilizes two SPE signals simultaneously generated at different wavelengths. In the experiment, we image stained and unstained biological tissues, and obtain two different images for each sample. Additionally, we propose an axial differential imaging technique to improve the contrast of SPE images, and verify its applicability to biological imaging.

Yamagiwa, Masatomo; Omura, Gen; Ozeki, Yasuyuki; Ishii, Makiko; Dang, Hieu Min; Kajiyama, Shin'ichiro; Suzuki, Takeshi; Fukui, Kiichi; Itoh, Kazuyoshi

2010-01-01

104

UNIDENTIFIED INFRARED EMISSION BANDS: PAHs or MAONs?  

SciTech Connect

We suggest that the carrier of the unidentified infrared emission (UIE) bands is an amorphous carbonaceous solid with mixed aromatic/aliphatic structures, rather than free-flying polycyclic aromatic hydrocarbon molecules. Through spectral fittings of the astronomical spectra of the UIE bands, we show that a significant amount of the energy is emitted by the aliphatic component, implying that aliphatic groups are an essential part of the chemical structure. Arguments in favor of an amorphous, solid-state structure rather than a gas-phase molecule as a carrier of the UIE are also presented.

Sun Kwok; Yong Zhang, E-mail: sunkwok@hku.hk [Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong (Hong Kong)

2013-07-01

105

Substantial band-gap narrowing of ?-Si 3N 4 induced by heavy Al doping  

NASA Astrophysics Data System (ADS)

Our first-principles study on the structural and electronic properties of Al-doped ?-Si 3N 4 predict a significant band-gap narrowing, which makes this material a more efficient phosphor. Strong attraction of substitutional and interstitial Al atoms leads to the formation of stable (3+1) complexes that behave as isoelectronic traps. The near-mid-gap states of the interstitials reduce nearly half of the band-gap of ?-Si 3N 4. Such a new nitride-based semiconductor could be a promising photocatalyst with high reactivity in solar irradiation or interior lighting in visible spectrum.

Xiao, W.; Geng, W. T.

2011-07-01

106

Narrow-band radiation wavelength measurement by processing digital photographs in RAW format  

SciTech Connect

The technique of measuring the mean wavelength of narrow-band radiation in the 455 - 625-nm range using the image of the emitting surface is presented. The data from the camera array unprocessed by the built-in processor (RAW format) are used. The method is applied for determining the parameters of response of holographic sensors. Depending on the wavelength and brightness of the image fragment, the mean square deviation of the wavelength amounts to 0.3 - 3 nm. (experimental techniques)

Kraiskii, A V; Mironova, T V; Sultanov, T T [P N Lebedev Physical Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2012-12-31

107

Usefulness of a Narrow-Band Reflectance Spectrophotometer in Evaluating Effects of Depigmenting Treatment  

Microsoft Academic Search

.   As a depigmenting treatment, combined topical applications of all-trans retinoic acid (atRA) aqueous gel and 5% hydroquinone,\\u000a 7% lactic acid ointment were used for Oriental patients with hyperpigmented skin lesions such as senile lentigines and nevus\\u000a spilus. A narrow-band reflectance spectrophotometer and a tristimulus colorimeter were used to evaluate objectively the intensity\\u000a of pigmentation and erythema at each clinical

Kotaro Yoshimura; Kiyonori Harii; Yuji Masuda; Motoji Takahashi; Takao Aoyama; Tatsuji Iga

2001-01-01

108

Narrow-band frequency analysis for laser-based glass thickness measurement  

Microsoft Academic Search

This paper presents a narrow-band frequency analysis approach for a new laser interferometric heterodyne system, which is used for noncontact glass bottle wall thickness measurement. The measurement signal consists of a number of spectral components, the strongest of which is a reliable representation of the above-mentioned thickness. A fast method for searching and locating this frequency is vital for real-time

Bing He; François Cabestaing; Jack-Gérard Postaire; Ruodan Zhang

2005-01-01

109

Some results of the narrow-band photometry of Comet Halley (1986 III)  

NASA Astrophysics Data System (ADS)

Narrow-band photometric observations of Comet Halley in the CN, C3, C2, H2O(+), CU, CB, and CR filters during October-November 1985 are presented. Molecular column densities and production rates for gases and dust particles are obtained. Photometric parameters n for CN, C3, C2, and dust particles in the Q of about r exp -n law are determined. The analysis of the gas and dust ratio as a function of the heliocentric distance is given.

Churyumov, K. I.; Rozenbush, V. K.; Rspayev, F. K.; Gorodetsky, D. I.

1990-06-01

110

Band gap narrowing in BaTiO{sub 3} nanoparticles facilitated by multiple mechanisms  

SciTech Connect

In the present work, BaTiO{sub 3} nanoparticles of four different size ranges were prepared by sol-gel method. The optical band gap of these particles at some size ranges has come down to 2.53?eV from 3.2?eV, resulting in substantial increase in optical absorption by these ferroelectric nanoparticles making them potential candidates for light energy harvesting. XRD results show the presence of higher compressive strain in 23?nm and 54?nm size particles, they exhibit a higher band gap narrowing, whereas tensile strain is observed in 31?nm and 34?nm particles, and they do not show the marginal band gap narrowing. The 23?nm and 54?nm particles also show a coupling of free carriers to phonons by increasing the intensity of LO phonon mode at 715?cm{sup ?1}. The higher surface charge density is expected in case of enhanced surface optical Raman modes (638?cm{sup ?1}) contained in 31 and 34?nm size particles. In addition to this, the red shift in an LO mode Raman spectral line at 305?cm{sup ?1} with decrease in particle size depicts the presence of phonon confinement in it. The enhanced optical absorption in 23?nm and 54?nm size particles with a narrowed band gap of 3?eV and 2.53?eV is due to exchange correlation interactions between the carriers present in these particles. In 31?nm and 34?nm range particles, the absorption got bleached exhibiting increased band gaps of 3.08?eV and 3.2?eV, respectively. It is due to filling up of conduction band resulting from weakening of exchange correlation interactions between the charge carriers. Hence, it is concluded that the band gap narrowing in the nanoparticles of average size 23?nm/54?nm is a consequence of multiple effects like strain, electron-phonon interaction, and exchange correlation interactions between the carriers which is subdued in some other size ranges like 31?nm/34?nm.

Ramakanth, S. [Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Hyderabad 500046 (India); James Raju, K. C., E-mail: kcjrsp@uohyd.ernet.in [Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Hyderabad 500046 (India); School of Physics, University of Hyderabad, Hyderabad 500046 (India)

2014-05-07

111

Narrow-band search of continuous gravitational-wave signals from Crab and Vela pulsars in Virgo VSR4 data  

NASA Astrophysics Data System (ADS)

In this paper we present the results of a coherent narrow-band search for continuous gravitational-wave signals from the Crab and Vela pulsars conducted on Virgo VSR4 data. In order to take into account a possible small mismatch between the gravitational-wave frequency and two times the star rotation frequency, inferred from measurement of the electromagnetic pulse rate, a range of 0.02 Hz around two times the star rotational frequency has been searched for both the pulsars. No evidence for a signal has been found and 95% confidence level upper limits have been computed assuming both that polarization parameters are completely unknown and that they are known with some uncertainty, as derived from x-ray observations of the pulsar wind torii. For Vela the upper limits are comparable to the spin-down limit, computed assuming that all the observed spin-down is due to the emission of gravitational waves. For Crab the upper limits are about a factor of 2 below the spin-down limit, and represent a significant improvement with respect to past analysis. This is the first time the spin-down limit is significantly overcome in a narrow-band search.

Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Ain, A.; Ajith, P.; Alemic, A.; Allen, B.; Allocca, A.; Amariutei, D.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Areeda, J. S.; Ashton, G.; Ast, S.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Aylott, B. E.; Babak, S.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barbet, M.; Barclay, S.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Bartlett, J.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bauer, Th. S.; Baune, C.; Bavigadda, V.; Behnke, B.; Bejger, M.; Belczynski, C.; Bell, A. S.; Bell, C.; Benacquista, M.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biscans, S.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackburn, L.; Blair, C. D.; Blair, D.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bojtos, P.; Bond, C.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, Sukanta; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Buchman, S.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Cadonati, L.; Cagnoli, G.; Calderón Bustillo, J.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Carbognani, F.; Caride, S.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C.; Colombini, M.; Cominsky, L.; Constancio, M.; Conte, A.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coulon, J.-P.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Cutler, C.; Dahl, K.; Canton, T. Dal; Damjanic, M.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dartez, L.; Dattilo, V.; Dave, I.; Daveloza, H.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Dominguez, E.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S.; Eberle, T.; Edo, T.; Edwards, M.; Edwards, M.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Essick, R.; Etzel, T.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Feldbaum, D.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fuentes-Tapia, S.; Fulda, P.; Fyffe, M.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S.; Garufi, F.; Gatto, A.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; Gergely, L. Á.; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gleason, J.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Goßler, S.; Gouaty, R.; Gräf, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guido, C. J.; Guo, X.; Gushwa, K.; Gustafson, E. K.; Gustafson, R.; Hacker, J.; Hall, E. D.; Hammond, G.; Hanke, M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Hee, S.; Heidmann, A.; Heintze, M.; Heinzel, G.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E.

2015-01-01

112

Imaging of the PAH Emission Bands in the Orion Bar  

NASA Technical Reports Server (NTRS)

The infrared spectrum of many planetary nebulae, HII regions, galactic nuclei, reflection nebulae, and WC stars are dominated by a set of narrow and broad features which for many years were called the "unidentified infrared bands". These bands have been attributed to several carbon-rich molecular species which all contain only carbon and hydrogen atoms, and fall into the class of PAH molecules or are conglomerates of PAH skeletons. If these bands are from PAHs, then PAHs contain 1-10% of the interstellar carbon, making them the most abundant molecular species in the interstellar medium after CO. From ground based telescopes, we have studied the emission bands assigned to C-H bond vibrations in PAHs (3.3, 11.3 microns) in the Orion Bar region, and showed that their distribution and intensities are consistent with a quantitative PAH model. We have recently obtained spectral images of the Orion Bar from the KAO at 6.2 and 7.7 microns using a 128 x 128 Si:Ga array camera in order to study the C-C modes of the PAH molecules. We will show these new data along with our existing C-H mode data set, and make a quantitative comparison of the data with the existing PAH model.

Bregman, Jesse; Harker, David; Rank, David; Temi, Pasqiale; Morrison, David (Technical Monitor)

1994-01-01

113

SEARCHING FOR NARROW EMISSION LINES IN X-RAY SPECTRA: COMPUTATION AND METHODS Taeyoung Park,1  

E-print Network

The detection and quantification of narrow emission lines in X-ray spectra is a challenging statistical task quasar emission. The detection of weak lines in noisy spectra is the main statistical problem- portant X-ray emission feature identified in AGN and quasar spectra is the iron K emission line (see

van Dyk, David

114

High open circuit voltage in regioregular narrow band gap polymer solar cells.  

PubMed

The regioregular narrow band gap (E(g) ~1.5 eV) conjugated polymer PIPCP was designed and synthesized. PIPCP contains a backbone comprised of CPDT-PT-IDT-PT repeat units (CPDT = cyclopentadithiophene, PT = pyridyl[2,1,3]thiadiazole, IDT = indacenodithiophene) and strictly organized PT orientations, such that the pyridyl N-atoms point toward the CPDT fragment. Comparison of PIPCP with the regiorandom counterpart PIPC-RA illustrates that the higher level of molecular order translates to higher power conversion efficiencies (PCEs) when incorporated into bulk heterojunction (BHJ) organic solar cells. Examination of thin films via absorption spectroscopy and grazing incidence wide-angle X-ray diffraction (GIWAXS) experiments provides evidence of higher order within thin films obtained by spin coating. Most significantly, we find that PIPCP:PC61BM blends yield devices with an open circuit voltage (V(oc)) of 0.86 V, while maintaining a PCE of ~6%. Comparison against a wide range of analogous narrow band gap conjugated polymers reveals that this V(oc) value is particularly high for a BHJ system with band gaps in the 1.4-1.5 eV range thereby indicating a very low E(g) - eV(oc) loss. PMID:25122541

Wang, Ming; Wang, Hengbin; Yokoyama, Takamichi; Liu, Xiaofeng; Huang, Ye; Zhang, Yuan; Nguyen, Thuc-Quyen; Aramaki, Shinji; Bazan, Guillermo C

2014-09-10

115

The Differences in Brain Activity between Narrow Band Noise and Pure Tone Tinnitus  

PubMed Central

Background Tinnitus is an auditory sensation characterized by the perception of sound or noise in the absence of any external sound source. Based on neurobiological research, it is generally accepted that most forms of tinnitus are attributable to maladaptive plasticity due to damage to auditory system. Changes have been observed in auditory structures such as the inferior colliculus, the thalamus and the auditory cortex as well as in non-auditory brain areas. However, the observed changes show great variability, hence lacking a conclusive picture. One of the reasons might be the selection of inhomogeneous groups in data analysis. Methodology The aim of the present study was to delineate the differences between the neural networks involved in narrow band noise and pure tone tinnitus conducting LORETA based source analysis of resting state EEG. Conclusions Results demonstrated that narrow band noise tinnitus patients differ from pure tone tinnitus patients in the lateral frontopolar (BA 10), PCC and the parahippocampal area for delta, beta and gamma frequency bands, respectively. The parahippocampal-PCC current density differences might be load dependent, as noise-like tinnitus constitutes multiple frequencies in contrast to pure tone tinnitus. The lateral frontopolar differences might be related to pitch specific memory retrieval. PMID:21048975

Vanneste, Sven; Plazier, Mark; van der Loo, Elsa; Van de Heyning, Paul; De Ridder, Dirk

2010-01-01

116

Ratiometric luminescence thermometry based on crystal-field alternation at the extremely narrow ?D? ? ?F? transition band of europium(III).  

PubMed

A dinuclear europium(III) complex with a structure of [BP-(Eu(III))2-(ODA)3] (BP = 2,2'-bipyridine-6,6'-dicarboxylic acid bis(N-hydroxy-succinimide) ester, ODA = diglycolic acid) shows a fully reversible emission spectral change at the extremely narrow (5)D0 ? (7)F2 transition band in response to temperature changes ranging from 283 K to 333 K. PMID:24686443

Yuasa, Junpei; Mukai, Ryusuke; Hasegawa, Yasuchika; Kawai, Tsuyoshi

2014-07-28

117

NPP VIIRS emissive band radiance calibration  

NASA Astrophysics Data System (ADS)

VIIRS thermal emissive bands (TEB) calibration data (blackbody and space counts) have been analyzed. The analysis results indicate that the Visible Infrared Imaging Radiometer Suite (VIIRS) TEB is stable and exceeds the specification. VIIRS Blackbody temperature is stable, too. The 6 platinum resistance thermometers (PRT) are also stable, except for the 3rd and 6th PRT have a periodic variation of 50 mK. Using the calibration data during the Blackbody temperature cool down and warm up, we found that noise equivalent deviation of temperatures (NEdT) varies with the Blackbody temperature. We developed a model that can predict the scene temperature dependent NEdT for the VIIRS M15 band. Comparisons between the VIIRS and other sensors such as AVHRR, MODIS and CrIS demonstrated that VIIRS TEB agrees generally with those sensors.

Liu, Quanhua; Cao, Changyong; Weng, Fuzhong

2012-09-01

118

A search for double-peaked narrow emission line galaxies and AGNs in the LAMOST DR1  

NASA Astrophysics Data System (ADS)

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) has released more than two million spectra, which provide the opportunity to search for double-peaked narrow emission line (NEL) galaxies and active galactic nuclei (AGNs). The double-peaked narrow-line profiles can be well modeled by two velocity components, respectively blueshifted and redshifted with respect to the systemic recession velocity. This paper presents 20 double-peaked NEL galaxies and AGNs found from LAMOST DR1 using a search method based on a multi-Gaussian fit of the narrow emission lines. Among them, ten have already been published by other authors, either listed as genuine double-peaked NEL objects or as asymmetric NEL objects, and the remaining ten are original discoveries. We discuss some possible origins for the double-peaked narrow-line features, such as interaction between jet and narrow line regions, interaction with companion galaxies, and black hole binaries. Spatially resolved optical imaging and/or follow-up observations in other spectral bands are needed to further discuss the physical mechanisms at work.

Shi, Zhi-Xin; Luo, A.-Li; Comte, Georges; Chen, Xiao-Yan; Wei, Peng; Zhao, Yong-Heng; Wu, Fu-Chao; Zhang, Yan-Xia; Shen, Shi-Yin; Yang, Ming; Wu, Hong; Wu, Xue-Bing; Zhang, Hao-Tong; Lei, Ya-Juan; Zhang, Jian-Nan; Wang, Ting-Gui; Jin, Ge; Zhang, Yong

2014-10-01

119

Measurement of the surface wavelength distribution of narrow-band radiation by a colorimetric method  

SciTech Connect

A method is suggested for determining the wavelength of narrow-band light from a digital photograph of a radiating surface. The digital camera used should be appropriately calibrated. The accuracy of the wavelength measurement is better than 1 nm. The method was tested on the yellow doublet of mercury spectrum and on the adjacent continuum of the incandescent lamp radiation spectrum. By means of the method suggested the homogeneity of holographic sensor swelling was studied in stationary and transient cases. (laser applications and other topics in quantum electronics)

Kraiskii, A V; Mironova, T V; Sultanov, T T [P N Lebedev Physical Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2010-09-10

120

Hydrogen in insulating oxide Y3Al5O12 strongly narrows the band gap  

NASA Astrophysics Data System (ADS)

We report an unusual band gap narrowing in Y3Al5O12 (YAG) insulating oxide after growing YAG single crystals in hydrogen atmosphere. Theory confirms that hydrogen interstitials as well as oxygen vacancies strongly shift the absorption spectrum towards lower energies. Furthermore, hydrogen eliminated all deep and shallow traps in the YAG structure and dramatically modified the optical and scintillation properties of YAG single crystals. We conclude that hydrogen plays a significant role in insulating oxides similar to its role in semiconductors and it may be used to passivate defects and improve exciton dynamics in oxides for optical and scintillation applications.

Winarski, D.; Persson, C.; Selim, F. A.

2014-12-01

121

Construction of narrow-band regenerative amplifier for momentum imaging spectroscopy of lithium dimer  

NASA Astrophysics Data System (ADS)

We constructed a Ti:Sapphire narrow-band regenerative amplifier as the probe laser of the experiment of momentum imaging spectroscopy of lithium dimer. The spectral profile of the regenerative cavity was designed by three birefringent filters and a plate of etalon. With 1.1-mJ pumping by the second harmonics of Nd:YLF laser, mode-locked seed pulses were amplified to ˜25 ?J at 1-kHz repetition, with the bandwidth of ˜0.7 cm-1.

Matsuoka, Leo; Hashimoto, Masashi; Yokoyama, Keiichi

2012-07-01

122

A search for narrow band signals with SERENDIP II: a progress report  

NASA Technical Reports Server (NTRS)

Commensal programs for the Search for Extraterrestrial Intelligence (SETI), carried out concurrently with conventional radio astronomical observing programs, can be an attractive and cost-effective means of exploring the large multidimensional search space intrinsic to this effort. Our automated commensal system, SERENDIP II, is a high resolution 131,072 channel spectrometer. It searches for 0.49 Hz signals in sequential 64,700 Hz bands of the IF signal from a radio telescope being used for an astronomical observation. Upon detection of a narrow band signal with power above a preset threshold, the frequency, power, time, and telescope direction are recorded for later study. The system has been tested at the Hat Creek Radio Astronomy Observatory 85 ft telescope and the NASA-JPL Deep Space Station (DSS 14) 64 m telescope. It is currently collecting data at the National Radio Astronomy Observatory 300 ft telescope.

Werthimer, D.; Brady, R.; Berezin, A.; Bowyer, S.

1988-01-01

123

A search for narrow band signals with SERENDIP II: a progress report.  

PubMed

Commensal programs for the Search for Extraterrestrial Intelligence (SETI), carried out concurrently with conventional radio astronomical observing programs, can be an attractive and cost-effective means of exploring the large multidimensional search space intrinsic to this effort. Our automated commensal system, SERENDIP II, is a high resolution 131,072 channel spectrometer. It searches for 0.49 Hz signals in sequential 64,700 Hz bands of the IF signal from a radio telescope being used for an astronomical observation. Upon detection of a narrow band signal with power above a preset threshold, the frequency, power, time, and telescope direction are recorded for later study. The system has been tested at the Hat Creek Radio Astronomy Observatory 85 ft telescope and the NASA-JPL Deep Space Station (DSS 14) 64 m telescope. It is currently collecting data at the National Radio Astronomy Observatory 300 ft telescope. PMID:11538322

Werthimer, D; Brady, R; Berezin, A; Bowyer, S

1988-01-01

124

The Cosmic Infrared Background Experiment: Flight Characterization Of The Ciber Narrow Band Spectrometer.  

NASA Astrophysics Data System (ADS)

Subtraction of the Zodiacal light foreground is the dominant source of uncertainty in absolute photometric measurements of the extra-galactic background at near-infrared to optical wavelengths. The second flight of the Cosmic Infrared Background ExpeRiment (CIBER) occurred on July 10th, 2010. CIBER is a NASA sounding rocket experiment carrying four co-aligned instruments including two imaging telescopes with wide passbands centered at 1 and 1.6 microns, respectively, as well as a low resolution spectrometer and a narrow-band spectrometer. THE CIBER spectrometers are absolutely calibrated in collaboration with NIST. The narrow-band spectrometer filter is centered on the Ca II solar Fraunhofer line at 854.2 nm and is designed to measure the equivalent width of the solar line reflected by the interplanetary dust in order to obtain an absolute measurement of the Zodiacal contribution to the infrared sky at that wavelength. In conjunction with measured low resolution spectrum from 700 to 1900 nm, this will provide an accurate independent check of the DIRBE Zodiacal light models. Here we describe the NBS instrument, calibration and in-flight characterization.

Levenson, Louis R.; Battle, J.; Bock, J. J.; Cooray, A.; Hristov, V.; Keating, B.; Lee, D.; Mason, P.; Matsumoto, T.; Matsuura, S.; Nam, U. W.; Renbarger, T.; Sullivan, I.; Suzuki, K.; Wada, T.; Zemcov, M.

2011-01-01

125

Fermion space charge in narrow-band gap semiconductors, Weyl semimetals and around highly charged nuclei  

E-print Network

The field of charged impurities in narrow-band gap semiconductors and Weyl semimetals can create electron-hole pairs when the total charge $Ze$ of the impurity exceeds a value $Z_{c}e$. The particles of one charge escape to infinity, leaving a screening space charge. The result is that the observable dimensionless impurity charge $Q_{\\infty}$ is less than $Z$ but greater than $Z_{c}$. There is a corresponding effect for nuclei with $Z >Z_{c} \\approx 170$, however in the condensed matter setting we find $Z_{c} \\simeq 10$. Thomas-Fermi theory indicates that $Q_{\\infty} = 0$ for the Weyl semimetal, but we argue that this is a defect of the theory. For the case of a highly-charged recombination center in a narrow band-gap semiconductor (or of a supercharged nucleus), the observable charge takes on a nearly universal value. In Weyl semimetals the observable charge takes on the universal value $Q_{\\infty} = Z_{c}$ set by the reciprocal of material's fine structure constant.

Kolomeisky, Eugene B; Zaidi, Hussain

2013-01-01

126

Nature of the narrow optical band in H*-aggregates: Dozy-chaos–exciton coupling  

SciTech Connect

Dozy chaos emerges as a combined effect of the collective chaotic motion of electrons and nuclei, and their chaotic electromagnetic interactions in the transient state of molecules experiencing quantum transitions. Following earlier discussions of the well-known Brönsted relations for proton-transfer reactions; the temperature-dependent electron transfer in Langmuir–Blodgett films; the shape of the optical bands of polymethine dye monomers, their dimers, and J-aggregates, this paper reports one more application of the dozy-chaos theory of molecular quantum transitions. The qualitative and quantitative explanations for shape of a narrow and blue-shifted optical absorption band in H{sup *}-aggregates is given on the basis of the dozy-chaos theory by taking into account the dozy-chaos–exciton coupling effect. It is emphasized that in the H{sup *}-aggregate chromophore (dimer of cyclic bis-thiacarbocyanines) there is a competition between two Frenkel exciton transitions through the chaotic reorganization motion of nuclear environment. As a result, the highly organized quantum transition to the upper exciton state becomes an exciton-induced source of dozy chaos for the low organized transition to the lower exciton state. This manifests itself in appearing the narrow peak and broad wing in the optical spectrum pattern of H{sup *}-aggregates. A similar enhancement in the H{sup *}-effect caused by the strengthening of the exciton coupling in H{sup *}-dimers, which could be achieved by synthesizing tertiary and quarternary thiacarbocyanine monomers, is predicted.

Egorov, Vladimir V., E-mail: egorov@photonics.ru [Photochemistry Center, Russian Academy of Sciences, Moscow, 119421 (Russian Federation)

2014-07-15

127

In vivo early diagnosis of gastric dysplasia using narrow-band image-guided Raman endoscopy  

NASA Astrophysics Data System (ADS)

We first report on the implementation of a novel narrow-band image-guided Raman endoscopy technique for in vivo diagnosis of gastric dysplasia. High-quality in vivo Raman spectra can be acquired from normal and dysplastic gastric mucosal tissue within 0.5 sec under narrow-band image (NBI) guidance at gastroscopy. Significant differences are observed in in vivo Raman spectra between normal (n=54) and dysplastic (n=18) gastric tissue from 30 gastric patients, particularly in the spectral ranges of 825 to 950, 1000 to 1100, 1250 to 1500, and 1600 to 1800 cm-1, which primarily contain signals related to proteins, nucleic acids, and lipids. The multivariate analysis [i.e., principal components analysis (PCA) and linear discriminant analysis (LDA)], together with the leave-one tissue site-out, cross validation on in vivo gastric Raman spectra yields a diagnostic sensitivity of 94.4% (17/18) and specificity of 96.3% (52/54) for distinction of gastric dysplastic tissue. This study suggests that narrowband image-guided Raman endoscopy associated with PCA-LDA diagnostic algorithms has potential for the noninvasive, in vivo early diagnosis and detection of gastric precancer during clinical gastroscopic examination.

Huang, Zhiwei; Bergholt, Mads Sylvest; Zheng, Wei; Lin, Kan; Ho, Khek Yu; Teh, Ming; Yeoh, Khay Guan

2010-05-01

128

Narrow-band double-pass superluminescent diodes emitting at 1060 nm  

SciTech Connect

Experimental data are presented which show that double-pass superluminescent diodes (SLDs) with fibre Bragg grating (FBG) based spectrally selective external reflectors offer emission linewidths in the range 0.1-1.0 nm, i.e., one to two orders of magnitude narrower in comparison with conventional SLDs and considerably broader in comparison with single-frequency semiconductor lasers. Their optical power at the single-mode fibre output reaches 5.0-8.0 mW, and can be raised to 50 mW using a semiconductor optical amplifier. (lasers)

Lobintsov, A A; Perevozchikov, M V; Shramenko, M V [Superlum Diodes Ltd., Moscow (Russian Federation); Yakubovich, S D [Moscow State Institute of Radio-Engineering, Electronics and Automation (Technical University), Moscow (Russian Federation)

2009-09-30

129

A proposed interim improvement to the Tevatron beam position monitors with narrow band crystal filters  

SciTech Connect

Since the start of Run II, we have found that we are unable to reliably and accurately measure the beam position with the present BPM system during high energy physics (HEP). This problem can be traced back to the analogue frontend called the AM/PM module which has trouble handling coalesced beam, but works well with uncoalesced beam. In this paper, we propose a simple fix to the AM/PM module so that we can measure the beam position during HEP. The idea is to use narrow band crystal filters which ring when pinged by coalesced beam so that the AM/PM module is tricked into thinking that it is measuring uncoalesced beam.

Cheng-Yang Tan

2003-08-25

130

Catalyzed Water Oxidation by Solar Irradiation of Band-Gap-Narrowed Semiconductors (Part 2. Overview).  

SciTech Connect

The objectives of this report are: (1) Investigate the catalysis of water oxidation by cobalt and manganese hydrous oxides immobilized on titania or silica nanoparticles, and dinuclear metal complexes with quinonoid ligands in order to develop a better understanding of the critical water oxidation chemistry, and rationally search for improved catalysts. (2) Optimize the light-harvesting and charge-separation abilities of stable semiconductors including both a focused effort to improve the best existing materials by investigating their structural and electronic properties using a full suite of characterization tools, and a parallel effort to discover and characterize new materials. (3) Combine these elements to examine the function of oxidation catalysts on Band-Gap-Narrowed Semiconductor (BGNSC) surfaces and elucidate the core scientific challenges to the efficient coupling of the materials functions.

Fujita,E.; Khalifah, P.; Lymar, S.; Muckerman, J.T.; Rodriguez, J.

2008-03-18

131

The method of narrow-band audio classification based on universal noise background model  

NASA Astrophysics Data System (ADS)

Audio classification is the basis of content-based audio analysis and retrieval. The conventional classification methods mainly depend on feature extraction of audio clip, which certainly increase the time requirement for classification. An approach for classifying the narrow-band audio stream based on feature extraction of audio frame-level is presented in this paper. The audio signals are divided into speech, instrumental music, song with accompaniment and noise using the Gaussian mixture model (GMM). In order to satisfy the demand of actual environment changing, a universal noise background model (UNBM) for white noise, street noise, factory noise and car interior noise is built. In addition, three feature schemes are considered to optimize feature selection. The experimental results show that the proposed algorithm achieves a high accuracy for audio classification, especially under each noise background we used and keep the classification time less than one second.

Rui, Rui; Bao, Chang-chun

2013-03-01

132

Catalyzed Water Oxidation by Solar Irradiation of Band-Gap-Narrowed Semiconductors (Part 1. Overview).  

SciTech Connect

The objectives of this report are: (1) Investigate the catalysis of water oxidation by cobalt and manganese hydrous oxides immobilized on titania or silica nanoparticles, and dinuclear metal complexes with quinonoid ligands in order to develop a better understanding of the critical water oxidation chemistry, and rationally search for improved catalysts. (2) Optimize the light-harvesting and charge-separation abilities of stable semiconductors including both a focused effort to improve the best existing materials by investigating their structural and electronic properties using a full suite of characterization tools, and a parallel effort to discover and characterize new materials. (3) Combine these elements to examine the function of oxidation catalysts on Band-Gap-Narrowed Semiconductor (BGNSC) surfaces and elucidate the core scientific challenges to the efficient coupling of the materials functions.

Fujita,E.; Khalifah, P.; Lymar, S.; Muckerman, J.T.; Rodgriguez, J.

2008-03-18

133

Band gap narrowing in zinc oxide-based semiconductor thin films  

SciTech Connect

A simple expression is proposed for the band gap narrowing (or shrinkage) in semiconductors using optical absorption measurements of spin coated 1 at.?% Ga-doped ZnO (with additional 0–1.5 at.?% zinc species) thin films as ?E{sub BGN}?=?Bn{sup 1/3} [1 ? (n{sub c}/n){sup 1/3}], where B is the fitting parameter, n is carrier concentration, and n{sub c} is the critical density required for shrinkage onset. Its uniqueness lies in not only describing variation of ?E{sub BGN} correctly but also allowing deduction of n{sub c} automatically for several M-doped ZnO (M: Ga, Al, In, B, Mo) systems. The physical significance of the term [1 ? (n{sub c}/n){sup 1/3}] is discussed in terms of carrier separation.

Kumar, Jitendra, E-mail: jkiitk@gmail.com, E-mail: akrsri@gmail.com; Kumar Srivastava, Amit, E-mail: jkiitk@gmail.com, E-mail: akrsri@gmail.com [Materials Science Programme, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

2014-04-07

134

Program for narrow-band analysis of aircraft flyover noise using ensemble averaging techniques  

NASA Technical Reports Server (NTRS)

A package of computer programs was developed for analyzing acoustic data from an aircraft flyover. The package assumes the aircraft is flying at constant altitude and constant velocity in a fixed attitude over a linear array of ground microphones. Aircraft position is provided by radar and an option exists for including the effects of the aircraft's rigid-body attitude relative to the flight path. Time synchronization between radar and acoustic recording stations permits ensemble averaging techniques to be applied to the acoustic data thereby increasing the statistical accuracy of the acoustic results. Measured layered meteorological data obtained during the flyovers are used to compute propagation effects through the atmosphere. Final results are narrow-band spectra and directivities corrected for the flight environment to an equivalent static condition at a specified radius.

Gridley, D.

1982-01-01

135

[Nursing care management in dermatological patient on phototherapy narrow band UVB].  

PubMed

Phototherapy with narrow band ultraviolet B is a treatment used in some dermatology units, and is the first choice in some dermatological diseases due to being comfortable and cheap. The aim of this paper is to describe the management and nursing care by grouping more specific diagnoses, following NANDA-NIC/NOC taxonomy, such as the methodology from application, technique, material, and personnel to space-related aspects, with the aim of avoiding the clinical variability and the possible associated risks for the patients, and for the nurses who administer the treatment. The continuity of the same nurse in the follow-up sessions stimulates the relationship between medical personnel and patients, key points for loyalty and therapeutic adherence. This paper examines a consensus procedure with the Dermatology Unit Team and accredited by the Hospital Quality Unit. PMID:23916523

de Argila Fernández-Durán, Nuria; Blasco Maldonado, Celeste; Martín Gómez, Mónica

2013-01-01

136

Generalized Lichen Nitidus Successfully Treated with Narrow-band UVB Phototherapy : Two Cases Report  

PubMed Central

Lichen nitidus (LN) is an uncommon chronic inflammatory skin disease composed of numerous, tiny, shiny, flesh-colored papules that are predominantly observed on the chest, abdomen, glans penis and upper extremities. The distribution of LN is most often localized, but in some cases it can become generalized. Because LN tends to be asymptomatic and presents spontaneous resolution within several years, it usually does not require treatment except in symptomatic, persistent and generalized cases. We describe a 28-yr-old man and a 7-yr-old boy with generalized LN where both cases improved with narrow-band ultraviolet B (NB-UVB) phototherapy plus topical steroid ointment. Both patients noted improvement within the first three treatments and showed almost complete resolution after 18 and 20 treatments, respectively. NB-UVB phototherapy may be an effective alternative therapy for the treatment of generalized LN, even for those patients in their childhood. PMID:17297274

Do, Mi-Ok; Kim, Myoung-Ju; Kim, Seong-Hyun; Myung, Ki-Bum

2007-01-01

137

Search for Muon-Associated NEUTRINO---> Electron - Neutrino Oscillations in a Narrow Band Neutrino Beam.  

NASA Astrophysics Data System (ADS)

An experiment that looked for the oscillation nu_mu Rightarrow nu _{e} was performed using a narrow band nu_mu beam produced by the AGS at Brookhaven National Lab. Both the nu_mu and nu_ {e} reactions in our detector are analyzed. The number of nu_{e} events found in the detector is compared to the expected background from Monte Carlo calculations and an excess of 22.4 +/- 5.6 +/- _sp{3.8}{4.4} events above background is found. The excess represents a 3 standard deviation effect and may suggest a neutrino oscillation. The ratio of the acceptance corrected number of nu_{e} and nu_mu events is calculated from the data. The value is {cal R} = {nu_{e}over nu_mu} = 0.0184 +/-.0085.

O'Brien, Edward John

138

a Muon Neutrino Going to Electron Neutrino Oscillation Search in the AGS New Narrow Band Beam  

NASA Astrophysics Data System (ADS)

We report the result of a long baseline search for the neutrino oscillation mode nu_ mu to nu_{e} at Brookhaven National Laboratory. The neutrino detector, a 226 metric ton segmented electromagnetic calorimeter followed by a toroidal muon spectrometer, is located at 1 km from the target of the new Narrow Band Beam at the Alternating Gradient Synchrotron. We collected 3 times 10^{19} protons on target at mean neutrino energies of 1.3 GeV and 1.5 GeV. No evidence for neutrino oscillations through this mode is observed. The 90% confidence limits obtained are Delta m^2 <=q 0.10 eV ^2 in the limit of large mixing angle, and sin^2 2theta <=q 0.016 in the limit of large Delta m^2 . ftn*Research supported by the National Science Foundation.

Kondakis, Nicholas

139

Anomalous resistivity and the origin of heavy mass in the two-band Hubbard model with one narrow band  

SciTech Connect

We search for marginal Fermi-liquid behavior in the two-band Hubbard model with one narrow band. We consider the limit of low electron densities in the bands and strong intraband and interband Hubbard interactions. We analyze the influence of electron polaron effect and other mechanisms of mass enhancement (related to momentum dependence of the self-energies) on the effective mass and scattering times of light and heavy components in the clean case (electron-electron scattering and no impurities). We find the tendency towards phase separation (towards negative partial compressibility of heavy particles) in the 3D case for a large mismatch between the densities of heavy and light bands in the strong-coupling limit. We also observe that for low temperatures and equal densities, the homogeneous state resistivity R(T) {approx} T{sub 2} behaves in a Fermi-liquid fashion in both 3D and 2D cases. For temperatures higher than the effective bandwidth for heavy electrons T > W{sub *}{sup h}, the coherent behavior of the heavy component is totally destroyed. The heavy particles move diffusively in the surrounding of light particles. At the same time, the light particles scatter on the heavy ones as if on immobile (static) impurities. In this regime, the heavy component is marginal, while the light one is not. The resistivity saturates for T > W{sub *}{sup h} in the 3D case. In 2D, the resistivity has a maximum and a localization tail due to weak-localization corrections of the Altshuler-Aronov type. Such behavior of resistivity could be relevant for some uranium-based heavy-fermion compounds like UNi{sub 2}Al{sub 3} in 3D and for some other mixed-valence compounds possibly including layered manganites in 2D. We also briefly consider the superconductive (SC) instability in the model. The leading instability is towards the p-wave pairing and is governed by the enhanced Kohn-Luttinger mechanism of SC at low electron density. The critical temperature corresponds to the pairing of heavy electrons via polarization of the light ones in 2D.

Kagan, M. Yu., E-mail: kagan@kapitza.ras.ru [Kapitza Institute for Physical Problems (Russian Federation); Val'kov, V. V. [Kirenskii Institute of Physics (Russian Federation)

2011-07-15

140

Rapid narrow band elution for on-line SPE using a novel solvent plug injection technique.  

PubMed

Determination of trace constituents in biological and environmental samples usually requires a pre-concentration step. While solid-phase extraction (SPE) has been widely used, it is slow, labor intensive and adversely affected by analytical errors from handling. On-line SPE eliminates some of the flaws but often suffers from solvent compatibility problems with the subsequent chromatography separation. In this study, we are presenting a technical solution for overcoming some of these compatibility issues, by utilizing a fully automated, focused SPE sample transfer technique utilizing narrow-band solvent plugs, for seamless hyphenation with high-performance liquid chromatography (HPLC) or flow injection mass spectrometry (MS). A wide range of pharmaceutical compounds was studied in different sample matrices. Short plugs of high elution strength solvent were generated by means of an electrically actuated sample loop and enrichment and transfer steps monitored using on-line SPE-MS. The impact of the solvent plugs on chromatographic separation was studied using hyphenated SPE-LC-MS. By carefully examining elution profiles of solvent plugs of different compositions, optimum conditions for quantitative elution within well-defined volumes were found for all substances. In addition, the highly focused elution bands resulted in excellent retention time and peak area reproducibilities when injected on-line onto HPLC columns. Finally, to demonstrate proof-of-principle, the fully integrated on-line SPE-LC-MS system was applied to the analysis of spiked urine and river water samples. PMID:22669308

Gode, David; Martin, Markus M; Steiner, Frank; Huber, Christian G; Volmer, Dietrich A

2012-08-01

141

Two cases of eczematid-like purpura of Doucas and Kapetanakis responsive to narrow band ultraviolet B treatment.  

PubMed

Eczematid-like purpura of Doucas and Kapetanakis is a type of pigmented purpuric dermatoses (PPDs) with eczematous changes in the purpuric surface. A 10-year-old male and a 44-year-old male patients were admitted to our clinics for itching and flaking of the skin rashes. Based on the clinical and histopathological evaluations, the rashes were identified as eczematid-like PPDs of Doucas and Kapetanakis. Both patients were treated with narrow band ultraviolet B. The lesions were remarkably regressed following the treatment. These cases reported due its rarity and good response to narrow band ultraviolet B. PMID:23458394

Karadag, Ayse Serap; Bilgili, Serap Gunes; Onder, Sevda; Calka, Omer

2013-04-01

142

THE PREVALENCE OF NARROW OPTICAL Fe II EMISSION LINES IN TYPE 1 ACTIVE GALACTIC NUCLEI  

SciTech Connect

From detailed spectral analysis of a large sample of low-redshift active galactic nuclei (AGNs) selected from the Sloan Digital Sky Survey, we demonstrate-statistically for the first time-that narrow optical Fe II emission lines, both permitted and forbidden, are prevalent in type 1 AGNs. Remarkably, these optical lines are completely absent in type 2 AGNs, across a wide luminosity range, from Seyfert 2 galaxies to type 2 quasars. We suggest that the narrow Fe II-emitting gas is confined to a disk-like geometry in the innermost regions of the narrow-line region on physical scales smaller than the obscuring torus.

Dong Xiaobo; Wang Jianguo; Wang Tinggui; Wang Huiyuan; Zhou Hongyan [Key Laboratory for Research in Galaxies and Cosmology, University of Sciences and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Ho, Luis C. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Fan Xiaohui [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

2010-10-01

143

Radio jet emission from GeV-emitting narrow-line Seyfert 1 galaxies  

E-print Network

We studied the radio emission from four radio-loud and gamma-ray-loud narrow-line Seyfert 1 galaxies. The goal was to investigate whether a relativistic jet is operating at the source, and quantify its characteristics. We relied on the most systematic monitoring of such system in the cm and mm radio bands which is conducted with the Effelsberg 100 m and IRAM 30 m telescopes and covers the longest time-baselines and the most radio frequencies to date. We extract variability parameters and compute variability brightness temperatures and Doppler factors. The jet powers were computed from the light curves to estimate the energy output. The dynamics of radio spectral energy distributions were examined to understand the mechanism causing the variability. All the sources display intensive variability that occurs at a pace faster than what is commonly seen in blazars. The flaring events show intensive spectral evolution indicative of shock evolution. The brightness temperatures and Doppler factors are moderate, imply...

Angelakis, E; Marchili, N; Foschini, L; Myserlis, I; Karamanavis, V; Komossa, S; Blinov, D; Krichbaum, T P; Sievers, A; Ungerechts, H; Zensus, J A

2015-01-01

144

A blue optical filter for narrow-band imaging in endoscopic capsules  

NASA Astrophysics Data System (ADS)

This paper presents the design, simulation, fabrication, and characterization of a thin-film Fabry-Perot resonator composed of titanium dioxide (TiO2) and silicon dioxide (SiO2) thin-films. The optical filter is developed to be integrated with a light emitting diode (LED) for enabling narrow-band imaging (NBI) in endoscopy. The NBI is a high resolution imaging technique that uses spectrally centered blue light (415 nm) and green light (540 nm) to illuminate the target tissue. The light at 415 nm enhances the imaging of superficial veins due to their hemoglobin absorption, while the light at 540 nm penetrates deeper into the mucosa, thus enhances the sub-epithelial vessels imaging. Typically the endoscopes and endoscopic capsules use white light for acquiring images of the gastrointestinal (GI) tract. However, implementing the NBI technique in endoscopic capsules enhances their capabilities for the clinical applications. A commercially available blue LED with a maximum peak intensity at 404 nm and Full Width Half Maximum (FWHM) of 20 nm is integrated with a narrow band blue filter as the NBI light source. The thin film simulations show a maximum spectral transmittance of 36 %, that is centered at 415 nm with FWHM of 13 nm for combined the blue LED and a Fabry Perot resonator system. A custom made deposition scheme was developed for the fabrication of the blue optical filter by RF sputtering. RF powered reactive sputtering at 200 W with the gas flows of argon and oxygen that are controlled for a 5:1 ratio gives the optimum optical conditions for TiO2 thin films. For SiO2 thin films, a non-reactive RF sputtering at 150 W with argon gas flow at 15 sccm results in the best optical performance. The TiO2 and SiO2 thin films were fully characterized by an ellipsometer in the wavelength range between 250 nm to 1600 nm. Finally, the optical performance of the blue optical filter is measured and presented.

Silva, M. F.; Ghaderi, M.; Goncalves, L. M.; de Graaf, G.; Wolffenbuttel, R. F.; Correia, J. H.

2014-05-01

145

Narrow band quantitative and multivariate electroencephalogram analysis of peri-adolescent period  

PubMed Central

Background The peri-adolescent period is a crucial developmental moment of transition from childhood to emergent adulthood. The present report analyses the differences in Power Spectrum (PS) of the Electroencephalogram (EEG) between late childhood (24 children between 8 and 13 years old) and young adulthood (24 young adults between 18 and 23 years old). Results The narrow band analysis of the Electroencephalogram was computed in the frequency range of 0–20 Hz. The analysis of mean and variance suggested that six frequency ranges presented a different rate of maturation at these ages, namely: low delta, delta-theta, low alpha, high alpha, low beta and high beta. For most of these bands the maturation seems to occur later in anterior sites than posterior sites. Correlational analysis showed a lower pattern of correlation between different frequencies in children than in young adults, suggesting a certain asynchrony in the maturation of different rhythms. The topographical analysis revealed similar topographies of the different rhythms in children and young adults. Principal Component Analysis (PCA) demonstrated the same internal structure for the Electroencephalogram of both age groups. Principal Component Analysis allowed to separate four subcomponents in the alpha range. All these subcomponents peaked at a lower frequency in children than in young adults. Conclusions The present approaches complement and solve some of the incertitudes when the classical brain broad rhythm analysis is applied. Children have a higher absolute power than young adults for frequency ranges between 0-20 Hz, the correlation of Power Spectrum (PS) with age and the variance age comparison showed that there are six ranges of frequencies that can distinguish the level of EEG maturation in children and adults. The establishment of maturational order of different frequencies and its possible maturational interdependence would require a complete series including all the different ages. PMID:22920159

2012-01-01

146

Gas Distributions in Comet ISON’s Coma: Concurrent Integral-Field Spectroscopy and Narrow-band Imaging.  

NASA Astrophysics Data System (ADS)

At a solar distance of 0.44 AU, Oort cloud comet C/2012 S1 (ISON) exhibited an outburst phase that was observed by small telescopes at the McDonald Observatory. In conjunction with narrow-band (14Å) imaging over a wide-field, an image-slicer spectrograph ( 20,000) simultaneously measured the spatial distribution of ISON’s coma over a 1.6 x 2.7 arcminute field made up of 246 individual spectra. More than fifty emission lines from C2, NH2, CO, H2O+ and Na were observed within a single Echelle order spanning 5868Å to 5930Å. Spatial reconstructions of these species reveal that ISON’s coma was quite elongated several thousand km along the axis perpendicular to its motion. The ion tail appeared distinctly broader than the neutral Na tail, providing strong evidence that Na in the coma did not originate by dissociative recombination of a sodium bearing molecular ion. Production rates increased from 1.6 ± 0.3 x 1023 to 5.8 ± 1 x 1023 Na atoms/s within 24 hours, outgassing much less than comparable comets relative to ISON’s water production. The anti-sunward Na tail was imaged >106 km from the nucleus. Its distribution indicates origins both near the nucleus and in the dust tail, with the ratio of these Na sources varying on hourly timescales due to outburst activity.

Schmidt, Carl; Johnson, Robert E.; Baumgardner, Jeffrey; Mendillo, Michael

2014-11-01

147

Numerical simulation of evaluation of surface breaking cracks by array-lasers generated narrow-band SAW  

NASA Astrophysics Data System (ADS)

Most of the factors limiting the extensive application of laser-based ultrasonic for nondestructive evaluation of surface breaking crack are its poor sensitivity, low efficiency relative to conventional contact ultrasonic methods and limit on the dimension of the cracks. For this reason, a new technique that multiplepulse narrow-band ultrasound generated by laser arrays has been proposed. It is found that crack detection dependent on spectrum of narrow-band ultrasound generated by laser arrays can be operated with low amplitude requirements. In this paper, the narrow-band ultrasound generated by pulse laser arrays interacting with surface breaking cracks has been simulated in detail by the finite element method (FEM) according to the thermoelastic theory. The pulsed array lasers were assumed to be transient heat source, and the surface acoustic wave (SAW) which propagating on the top of the plate was computed based on thermoelastic theory. Then the frequency spectrums of both reflected waves by crack and transmission ones through crack were compared with the direct waves. Results demonstrate that multiple-frequency components of the narrow-band ultrasound were varied with change of the depth of surface breaking cracks significantly, which provides the possibility for precise evaluation of surface breaking cracks.

Dong, Li-Ming; Ni, Chen-Yin; Shen, Zhong-Hua; Ni, Xiao-Wu

2011-09-01

148

Absorption of Narrow-Gap HgCdTe Near the Band Edge Including Nonparabolicity and the Urbach Tail  

E-print Network

Absorption of Narrow-Gap HgCdTe Near the Band Edge Including Nonparabolicity and the Urbach Tail, USA. 6.--e-mail: yonchang@uic.edu An analytical model describing the absorption behavior of Hg1-x. This model smoothly fits experimental absorption coefficients over energies ranging from the Urbach tail

Flatte, Michael E.

149

Narrow-band imaging observation of colorectal lesions using NICE classification to avoid discarding significant lesions  

PubMed Central

AIM: To assess the risk of failing to detect diminutive and small colorectal cancers with the “resect and discard” policy. METHODS: Patients who received colonoscopy and polypectomy were recruited in the retrospective study. Probable histology of the polyps was predicted by six colonoscopists by the use of NICE classification. The incidence of diminutive and small colorectal cancers and their endoscopic features were assessed. RESULTS: In total, we found 681 cases of diminutive (1-5 mm) lesions in 402 patients and 197 cases of small (6-9 mm) lesions in 151 patients. Based on pathology of the diminutive and small polyps, 105 and 18 were non-neoplastic polyps, 557 and 154 were low-grade adenomas, 18 and 24 were high-grade adenomas or intramucosal/submucosal (SM) scanty invasive carcinomas, 1 and 1 were SM-d carcinoma, respectively. The endoscopic features of invasive cancer were classified as NICE type 3 endoscopically. CONCLUSION: The risk of failing to detect diminutive and small colorectal invasive cancer with the “resect and discard” strategy might be avoided through the use of narrow-band imaging observation with the NICE classification scheme and magnifying endoscopy. PMID:25512769

Hattori, Santa; Iwatate, Mineo; Sano, Wataru; Hasuike, Noriaki; Kosaka, Hidekazu; Ikumoto, Taro; Kotaka, Masahito; Ichiyanagi, Akihiro; Ebisutani, Chikara; Hisano, Yasuko; Fujimori, Takahiro; Sano, Yasushi

2014-01-01

150

Three-step H- charge exchange injection with a narrow-band laser  

NASA Astrophysics Data System (ADS)

This paper presents a scheme for three-step laser-based stripping of an H- beam for charge exchange injection into a high-intensity proton ring. First, H- atoms are converted to H0 by Lorentz stripping in a strong magnetic field, then neutral hydrogen atoms are excited from the ground state to upper levels by a laser, and the remaining electron, now more weakly bound, is stripped in a strong magnetic field. The energy spread of the beam particles gives rise to a Doppler broadened absorption linewidth, which makes for an inefficient population of the upper state by a narrow-band laser. We propose to overcome this limitation with a “frequency sweeping” arrangement, which populates the upper state with almost 100% efficiency. We present estimates of peak laser power and describe a method to reduce the power by tailoring the dispersion function at the laser-particle beam interaction point. We present a scheme for reducing the average power requirements by using an optical ring resonator. Finally, we discuss an experimental setup to demonstrate this approach in a proof-of-principle experiment.

Danilov, V.; Aleksandrov, A.; Assadi, S.; Henderson, S.; Holtkamp, N.; Shea, T.; Shishlo, A.; Braiman, Y.; Liu, Y.; Barhen, J.; Zacharia, T.

2003-05-01

151

Narrow-band autocorrelation function features for the automatic recognition of acoustic environments.  

PubMed

Acoustic environments are typically composed of multiple sound sources of different typologies, making them especially complex to model and parameterize. To develop an automatic acoustic environment recognition system, this work proposes a spectro-temporal signal parameterization technique inspired by human perception. The proposed parameters are derived from the analysis of the autocorrelation function of narrow-band signals (NB-ACF) obtained from an auditory gammatone filter bank. Five features related to acoustic phenomena are extracted from the NB-ACF to parameterize sound signals. Experiments are conducted on a 4?h sound database (composed of 15 different acoustic environments) employing four different machine learning techniques: K-nearest neighbor, Gaussian mixture models, neural networks and support vector machines. The averaged recognition rates increase by 4.5% when using the proposed NB-ACF features instead of the popular Mel frequency cepstral coefficients. The improvement is even greater (5.6%) when the features are tested in acoustic environments from unknown locations. These results are attributed to the better modeling of the acoustic environments thanks to the complementarity of the spectro-temporal features derived from NB-ACF analysis. PMID:23862894

Valero, Xavier; Alías, Francesc

2013-07-01

152

Diagnosis of early gastric cancer using narrow band imaging and acetic acid  

PubMed Central

AIM: To determine whether the endoscopic findings of depressed-type early gastric cancers (EGCs) could precisely predict the histological type. METHODS: Ninety depressed-type EGCs in 72 patients were macroscopically and histologically identified. We evaluated the microvascular (MV) and mucosal surface (MS) patterns of depressed-type EGCs using magnifying endoscopy (ME) with narrow-band imaging (NBI) (NBI-ME) and ME enhanced by 1.5% acetic acid, respectively. First, depressed-type EGCs were classified according to MV pattern by NBI-ME. Subsequently, EGCs unclassified by MV pattern were classified according to MS pattern by enhanced ME (EME) images obtained from the same angle. RESULTS: We classified the depressed-type EGCs into the following 2 MV patterns using NBI-ME: a fine-network pattern that indicated differentiated adenocarcinoma (25/25, 100%) and a corkscrew pattern that likely indicated undifferentiated adenocarcinoma (18/23, 78.3%). However, 42 of the 90 (46.7%) lesions could not be classified into MV patterns by NBI-ME. These unclassified lesions were then evaluated for MS patterns using EME, which classified 33 (81.0%) lesions as MS patterns, diagnosed as differentiated adenocarcinoma. As a result, 76 of the 90 (84.4%) lesions were matched with histological diagnoses using a combination of NBI-ME and EME. CONCLUSION: A combination of NBI-ME and EME was useful in predicting the histological type of depressed-type EGC.

Matsuo, Ken; Takedatsu, Hidetoshi; Mukasa, Michita; Sumie, Hiroaki; Yoshida, Hikaru; Watanabe, Yasutomo; Akiba, Jun; Nakahara, Keita; Tsuruta, Osamu; Torimura, Takuji

2015-01-01

153

A Narrow-band Multispectral Instrument for the Measurement of Low Density Biomass  

NASA Astrophysics Data System (ADS)

During 2001, a team of scientists and engineers from NASA Goddard Space Flight Center, at the request of NASA Headquarters, lead a planning activity for future studies of the sources, sinks, and transport of carbon in the atmosphere, on land, and in the oceans. One outcome of this study was a survey of critical gaps in our current measurement suite and identification of the types of instruments that could provide this missing information. Estimating biomass in ecosystems dominated by vegetation of short-stature (< 5 m), such as grasslands and shrub lands, was one of the gaps identified. An instrument with multiple narrow bands in the visible and near infrared was one possibility for filling this gap. In addition, such an instrument might prove helpful in conjunction with lidar measurements for characterizing high density biomass ecosystems such as tropical and boreal forest. A summary of the study and the basis for the recommendations will be presented. The characteristics of a low density biomass instrument, including measurement specifications and considerations, design alternatives including full VNIR and SWIR spectral coverage, and possible spacecraft accommodations, will be discussed. One or more aircraft versions of this type of instrument could be flown as part of the North American Carbon Program's field campaign. This could test the current specifications and design alternatives, thereby helping to guide selection of the best approach for a possible spaceborne instrument, as well as provide valuable information for the campaign itself.

Gervin, J. C.; Knox, R. G.; Hall, F. G.; McClain, C. R.; Caruso, P. S.

2002-12-01

154

Non-sequential narrow band imaging for targeted biopsy and monitoring of gastric intestinal metaplasia  

PubMed Central

AIM: To evaluate the efficacy of non-sequential narrow band imaging (NBI) for a better recognition of gastric intestinal metaplasia (GIM). METHODS: Previously diagnosed GIM patients underwent targeted biopsy from areas with and without GIM, as indicated by NBI, twice at an interval of 1 year. The authors compared the endoscopic criteria such as light blue crest (LBC), villous pattern (VP), and large long crest (LLC) with standard histology. The results from two surveillance endoscopies were compared with histology results for sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and likelihood ratio of positive test (LR+). The number of early gastric cancer cases detected was also reported. RESULTS: NBI targeted biopsy was performed in 38 and 26 patients during the first and second surveillance endoscopies, respectively. There were 2 early gastric cancers detected in the first endoscopy. No cancer was detected from the second study. Surgical and endoscopic resections were successfully performed in each patient. Sensitivity, specificity, PPV, NPV, and LR+ of all 3 endoscopic criteria during the first/second surveillances were 78.8%/91.3%, 82.5%/89.1%, 72.8%/77.8%, 86.8%/96.1, and 4.51/8.4, respectively. LBC provided the highest LR+ over VP and LLC. CONCLUSION: Non-sequential NBI is useful for GIM targeted biopsy. LBC provides the most sensitive reading. However, the optimal duration between two surveillances requires further study. PMID:21455334

Rerknimitr, Rungsun; Imraporn, Boonlert; Klaikeaw, Naruemon; Ridtitid, Wiriyaporn; Jutaghokiat, Sukprasert; Ponauthai, Yuwadee; Kongkam, Pradermchai; Kullavanijaya, Pinit

2011-01-01

155

Narrow-band imaging with magnifying endoscopy for the evaluation of gastrointestinal lesions  

PubMed Central

Narrow band imaging (NBI) endoscopy is an optical image enhancing technology that allows a detailed inspection of vascular and mucosal patterns, providing the ability to predict histology during real-time endoscopy. By combining NBI with magnification endoscopy (NBI-ME), the accurate assessment of lesions in the gastrointestinal tract can be achieved, as well as the early detection of neoplasia by emphasizing neovascularization. Promising results of the method in the diagnosis of premalignant and malignant lesions of gastrointestinal tract have been reported in clinical studies. The usefulness of NBI-ME as an adjunct to endoscopic therapy in clinical practice, the potential to improve diagnostic accuracy, surveillance strategies and cost-saving strategies based on this method are summarized in this review. Various classification systems of mucosal and vascular patterns used to differentiate preneoplastic and neoplastic lesions have been reviewed. We concluded that the clinical applicability of NBI-ME has increased, but standardization of endoscopic criteria and classification systems, validation in randomized multicenter trials and training programs to improve the diagnostic performance are all needed before the widespread acceptance of the method in routine practice. However, published data regarding the usefulness of NBI endoscopy are relevant in order to recommend the method as a reliable tool in diagnostic and therapy, even for less experienced endoscopists.

Boeriu, Alina; Boeriu, Cristian; Drasovean, Silvia; Pascarenco, Ofelia; Mocan, Simona; Stoian, Mircea; Dobru, Daniela

2015-01-01

156

Narrow-band imaging with magnifying endoscopy for the evaluation of gastrointestinal lesions.  

PubMed

Narrow band imaging (NBI) endoscopy is an optical image enhancing technology that allows a detailed inspection of vascular and mucosal patterns, providing the ability to predict histology during real-time endoscopy. By combining NBI with magnification endoscopy (NBI-ME), the accurate assessment of lesions in the gastrointestinal tract can be achieved, as well as the early detection of neoplasia by emphasizing neovascularization. Promising results of the method in the diagnosis of premalignant and malignant lesions of gastrointestinal tract have been reported in clinical studies. The usefulness of NBI-ME as an adjunct to endoscopic therapy in clinical practice, the potential to improve diagnostic accuracy, surveillance strategies and cost-saving strategies based on this method are summarized in this review. Various classification systems of mucosal and vascular patterns used to differentiate preneoplastic and neoplastic lesions have been reviewed. We concluded that the clinical applicability of NBI-ME has increased, but standardization of endoscopic criteria and classification systems, validation in randomized multicenter trials and training programs to improve the diagnostic performance are all needed before the widespread acceptance of the method in routine practice. However, published data regarding the usefulness of NBI endoscopy are relevant in order to recommend the method as a reliable tool in diagnostic and therapy, even for less experienced endoscopists. PMID:25685267

Boeriu, Alina; Boeriu, Cristian; Drasovean, Silvia; Pascarenco, Ofelia; Mocan, Simona; Stoian, Mircea; Dobru, Daniela

2015-02-16

157

Effects of Narrow Band UVB (311 nm) Irradiation on Epidermal Cells.  

PubMed

Ultraviolet radiation (UVR) is known to be one of the most important environmental hazards acting on the skin. It was revealed that chronic exposure to UVR accelerates skin aging, induces immunosuppression and may lead to the development of skin cancers. On the other hand, UVR has been shown to be effective in the treatment of numerous skin diseases and thus, various phototherapy modalities have been developed to date. Narrow-band ultraviolet B (NB-UVB) emitting a light with a peak around 311 nm has been demonstrated to be effective in the treatment of various skin disorders; currently it is one of the most commonly used phototherapy devices. Despite NB-UVB has been developed more than 30 years ago, the exact mechanism of its therapeutic action remains poorly understood. To date, most of NB-UVB effects were attributed to its influence on immune cells; however, nearly 90% of NB-UVB irradiation is absorbed by epidermis and keratinocytes seem to be important players in mediating NB-UVB biological activity. Here, we have reviewed the current data about the influence of NB-UVB on epidermal cells, with a special emphasis on cell proliferation and death. PMID:23594996

Reich, Adam; M?drek, Karolina

2013-01-01

158

THE BALDWIN EFFECT IN THE NARROW EMISSION LINES OF ACTIVE GALACTIC NUCLEI  

SciTech Connect

The anti-correlations between the equivalent widths of emission lines and the continuum luminosity in active galactic nuclei (AGNs), known as the Baldwin effect, are well established for broad lines, but are less well studied for narrow lines. In this paper we explore the Baldwin effect of narrow emission lines over a wide range of ionization levels and critical densities using a large sample of broad-line, radio-quiet AGNs taken from Sloan Digital Sky Survey Data Release 4. These type 1 AGNs span three orders of magnitude in continuum luminosity. We show that most narrow lines show a similar Baldwin effect slope of about -0.2, while the significant deviations of the slopes for [N II] {lambda}6583, [O II] {lambda}3727, [Ne V] {lambda}3425, and the narrow component of H{alpha} can be explained by the influence of metallicity, star formation contamination, and possibly by the difference in the shape of the UV-optical continuum. The slopes do not show any correlation with either the ionization potential or the critical density. We show that a combination of 50% variations in continuum near 5100 A and a lognormal distribution of observed luminosity can naturally reproduce a constant Baldwin effect slope of -0.2 for all narrow lines. The variations of the continuum could be due to variability, intrinsic anisotropic emission, or an inclination effect.

Zhang, Kai; Wang, Ting-Gui; Dong, Xiao-Bo [Key Laboratory for Research in Galaxies and Cosmology, The University of Sciences and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China)] [Key Laboratory for Research in Galaxies and Cosmology, The University of Sciences and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Gaskell, C. Martin, E-mail: zkdtc@mail.ustc.edu.cn, E-mail: twang@ustc.edu.cn, E-mail: xbdong@ustc.edu.cn, E-mail: martin.gaskell@uv.cl [Centro de Astrofisica de Valparaiso y Departamento de Fisica y Astronomia, Facultad de Ciencias, Universidad de Valparaiso, Av. Gran Bretana 1111, Valparaiso (Chile)

2013-01-01

159

Narrow-band, narrow-field-of-view Raman lidar with combined day and night capability for tropospheric water-vapor profile measurements.  

PubMed

We describe a high-performance Raman lidar system with combined day and night capability for tropospheric water-vapor profile measurements. The system incorporates high-performance UV interference filters and a narrow-band, dual-field-of-view receiver for rejection of background sunlight. Daytime performance has been demonstrated up to 5 km with 150-m vertical and 5-min temporal averaging. The nighttime performance is significantly better with measurements routinely extending from 10 to 12 km with 75-m range resolution and a 5-min temporal average. We describe design issues for daytime operation and a novel daytime calibration technique. PMID:18305815

Bisson, S E; Goldsmith, J E; Mitchell, M G

1999-03-20

160

Narrow-band, narrow-field-of-view Raman lidar with combined day and night capability for tropospheric water-vapor profile measurements  

SciTech Connect

We describe a high-performance Raman lidar system with combined day and night capability for tropospheric water-vapor profile measurements. The system incorporates high-performance UV interference filters and a narrow-band, dual-field-of-view receiver for rejection of background sunlight. Daytime performance has been demonstrated up to 5 km with 150-m vertical and 5-min temporal averaging. The nighttime performance is significantly better with measurements routinely extending from 10 to 12 km with 75-m range resolution and a 5-min temporal average. We describe design issues for daytime operation and a novel daytime calibration technique. {copyright} 1999 Optical Society of America

Bisson, S.E.; Goldsmith, J.E.; Mitchell, M.G. [Diagnostics Research Division, Sandia National Laboratories, 7011 East Avenue, P.O. Box 969, Livermore, California 94551-5149 (United States)

1999-03-01

161

Narrow-band imaging of fields around optically-thick absorption systems: The line-of-sight towards Q 0000-2619  

NASA Astrophysics Data System (ADS)

In this paper we describe deeper observations, both imaging and spectroscopy, of the most distant radio-quiet Ly-alpha galaxy known so far, at redshift of z = 3.428 (galaxy G2) and of other faint objects in the field around the QSO 0000 - 2619. Galaxy G2, which we discovered in the field around the damped absorber of the QSO with narrow-band imaging tuned to detect Ly-alpha emission at the redshift of the absorption system, is the best primaeval galaxy candidate identified so far. Here we report measurements of its restframe UV spectral energy distribution in the interval lambda lambda 1000, 1700 A, in particular the depression of the continuum due to the blanketing of the intervening Ly-alpha forest and the Ly-alpha emission line, and give better upper limits for the high-ionization emission lines, such as NV and CIV. We conclude that this object is very likely a primaeval galaxy observed during a major episode of star formation and in which dust does not extinguish the Ly-alpha emission. We also present Ly-alpha narrow-band imaging of the galaxy which causes the damped absorber in the spectrum of the QSO. No emission is detected, down to a 3 sigma upper limit of 1.2 x 10-17 erg/s/sq cm in an aperture of 2 arcsec in diameter. A corresponding upper limit to the rest-frame equivalent width is 6 A. Similar limits apply also to other 13 flat-spectrum z greater than 3 galaxy candidates identified in the same field by Steidel & Hamilton, if their redshift is such that their Ly-alpha emission falls within our narrow-band filter. However, from their rest-frame UV continuum luminosity, we estimate that the star formation rates for these galaxies are in the range 30 to 100 solar mass/yr. This would suggest that radioquiet primaeval galaxies, though in a star-forming phase, are not characterized by the intense Ly-alpha emission and large star formation rates (SFRs) typical of radio-galaxies. If these candidates are confirmed to be at similar redshifts than those of G2 and the galaxy responsible for the damped system of the QSO, then this association of galaxies would be the most distant cluster observed so far, with a total stellar mass of the order of 1013 solar mass (throughout this paper we assume H0 = 50 km/s/Mpc and Omega = 0, unless differently stated).

Giavalisco, M.; Macchetto, F. D.; Sparks, W. B.

1994-08-01

162

Development of inexpensive optical broad- and narrow-band sensors for ecosystem research  

NASA Astrophysics Data System (ADS)

The observation and monitoring of ecosystem processes are great challenges in environmental science, due to the dynamic and complexity of such procedures. To describe and understand biotic and abiotic processes and their interaction it is necessary to acquire multiple parameters, which are influencing the natural regime. Essential issues are: the detection of spatial heterogeneities and scale overlapping procedures in the environment. To overcome these problems an adequate monitoring system should cover a representative area as well as have a sufficient resolution in time and space. Hence, the needed quantity of sensors (depending on the observed parameters or processes) can be enormous. According to these issues, there is a high demand on low-cost sensor technologies (with adequate performances) to realize a delicate monitoring platform. In the case of vegetation processes, one key feature is to characterize photosynthetic activity of the plants in detail. Common investigation methods are based on optical measurements. Here photosynthetically active radiation (PAR) sensors and hyperspectral sensors are in major use. Photosynthetically active radiation (solar radiation from 400 to 700 nanometers) designates the spectral range that photosynthetic organisms are able to use in the process of photosynthesis. PAR sensors enable the detection of the reflected solar light of the vegetation in whole the PAR wave band. The amount of absorption indicates photosynthetic activity of the plant. Hyperspectral sensors observe specific parts of the solar light spectrum and facilitate the determination of the main pigment classes (Chlorophyll, Carotenoid and Anthocyanin). Due to absorption of pigments they producing a specific spectral signature in the visible part of the electromagnetic spectrum (narrow-band peaks). If vegetation is affected by water or nutritional deficience the proportion of light-absorbing pigments is reduced which finally results in an overall reduced light absorption. The resulting spectral signature then differs from usual reflectance patterns and can be used as stress indicator. Hence, reflectances between 550-700 nm are extremely sensitive regarding changing Chlorophyll contents. Both kinds of sensors based on semiconductor technologies whereby the material input can kept on low level. This work presents the development and testing of a practical, rugged, and inexpensive PAR and hyperspectral sensor. The sensors were made from a gallium arsenide phosphide (GaAsP) photodiodes and silicon photodiodes with different interference filters. First results of recorded long term in-situ data and linear regressions (in comparison to commercial products) show extremely high performances (coefficient of determination higher than 0.99) of the PAR sensors simultaneous to the cost cutting.

Mollenhauer, Hannes; Cuntz, Thomas; Bumberger, Jan

2014-05-01

163

Assessing the Temperature Dependence of Narrow-Band Raman Water Vapor Lidar Measurements: A Practical Approach  

NASA Technical Reports Server (NTRS)

Narrow-band detection of the Raman water vapor spectrum using the lidar technique introduces a concern over the temperature dependence of the Raman spectrum. Various groups have addressed this issue either by trying to minimize the temperature dependence to the point where it can be ignored or by correcting for whatever degree of temperature dependence exists. The traditional technique for performing either of these entails accurately measuring both the laser output wavelength and the water vapor spectral passband with combined uncertainty of approximately 0.01 nm. However, uncertainty in interference filter center wavelengths and laser output wavelengths can be this large or larger. These combined uncertainties translate into uncertainties in the magnitude of the temperature dependence of the Raman lidar water vapor measurement of 3% or more. We present here an alternate approach for accurately determining the temperature dependence of the Raman lidar water vapor measurement. This alternate approach entails acquiring sequential atmospheric profiles using the lidar while scanning the channel passband across portions of the Raman water vapor Q-branch. This scanning is accomplished either by tilt-tuning an interference filter or by scanning the output of a spectrometer. Through this process a peak in the transmitted intensity can be discerned in a manner that defines the spectral location of the channel passband with respect to the laser output wavelength to much higher accuracy than that achieved with standard laboratory techniques. Given the peak of the water vapor signal intensity curve, determined using the techniques described here, and an approximate knowledge of atmospheric temperature, the temperature dependence of a given Raman lidar profile can be determined with accuracy of 0.5% or better. A Mathematica notebook that demonstrates the calculations used here is available from the lead author.

Whiteman, David N.; Venable, Demetrius D.; Walker, Monique; Cardirola, Martin; Sakai, Tetsu; Veselovskii, Igor

2013-01-01

164

Assessing the temperature dependence of narrow-band Raman water vapor lidar measurements: a practical approach.  

PubMed

Narrow-band detection of the Raman water vapor spectrum using the lidar technique introduces a concern over the temperature dependence of the Raman spectrum. Various groups have addressed this issue either by trying to minimize the temperature dependence to the point where it can be ignored or by correcting for whatever degree of temperature dependence exists. The traditional technique for performing either of these entails accurately measuring both the laser output wavelength and the water vapor spectral passband with combined uncertainty of approximately 0.01 nm. However, uncertainty in interference filter center wavelengths and laser output wavelengths can be this large or larger. These combined uncertainties translate into uncertainties in the magnitude of the temperature dependence of the Raman lidar water vapor measurement of 3% or more. We present here an alternate approach for accurately determining the temperature dependence of the Raman lidar water vapor measurement. This alternate approach entails acquiring sequential atmospheric profiles using the lidar while scanning the channel passband across portions of the Raman water vapor Q-branch. This scanning is accomplished either by tilt-tuning an interference filter or by scanning the output of a spectrometer. Through this process a peak in the transmitted intensity can be discerned in a manner that defines the spectral location of the channel passband with respect to the laser output wavelength to much higher accuracy than that achieved with standard laboratory techniques. Given the peak of the water vapor signal intensity curve, determined using the techniques described here, and an approximate knowledge of atmospheric temperature, the temperature dependence of a given Raman lidar profile can be determined with accuracy of 0.5% or better. A Mathematica notebook that demonstrates the calculations used here is available from the lead author. PMID:23913054

Whiteman, David N; Venable, Demetrius D; Walker, Monique; Cadirola, Martin; Sakai, Tetsu; Veselovskii, Igor

2013-08-01

165

Investigation of relationships among gastroesophageal reflux disease subtypes using narrow band imaging magnifying endoscopy  

PubMed Central

AIM: To investigate the relationships among subtypes of gastroesophageal reflux disease (GERD) using narrow band imaging (NBI) magnifying endoscopy. METHODS: A reflux disease questionnaire was used to screen 120 patients representing the three subtypes of GERD (n = 40 for each subtypes): nonerosive reflux disease (NERD), reflux esophagitis (RE) and Barrett’s esophagus (BE). NBI magnifying endoscopic procedure was performed on the patients as well as on 40 healthy controls. The demographic and clinical characteristics, and NBI magnifying endoscopic features, were recorded and compared among the groups. Targeted biopsy and histopathological examination were conducted if there were any abnormalities. SPSS 18.0 software was used for all statistical analysis. RESULTS: Compared with healthy controls, a significantly higher proportion of GERD patients had increased number of intrapapillary capillary loops (IPCLs) (78.3% vs 20%, P < 0.05), presence of microerosions (41.7% vs 0%, P < 0.05), and a non-round pit pattern below the squamocolumnar junction (88.3% vs 30%, P < 0.05). The maximum (228 ± 4.8 vs 144 ± 4.7, P < 0.05), minimum (171 ± 3.8 vs 103 ± 4.4, P < 0.05), and average (199 ± 3.9 vs 119 ± 3.9, P < 0.05) numbers of IPCLs/field were also significantly greater in GERD patients. However, comparison among groups of the three subtypes showed no significant differences or any linear trend, except that microerosions were present in 60% of the RE patients, but in only 35% and 30% of the NERD and BE patients, respectively (P < 0.05). CONCLUSION: Patients with GERD, irrespective of subtype, have similar micro changes in the distal esophagus. The three forms of the disease are probably independent of each other. PMID:24363532

Lv, Jing; Liu, Dong; Ma, Shi-Yang; Zhang, Jun

2013-01-01

166

Detection of Mucosal Recurrent Nasopharyngeal Carcinomas After Radiotherapy With Narrow-Band Imaging Endoscopy  

SciTech Connect

Purpose: This study evaluated the feasibility of screening mucosal recurrent nasopharyngeal carcinoma with narrow-band imaging (NBI) endoscopy. Methods and Materials: One hundred and six patients were enrolled. All patients underwent conventional white-light (WL) endoscopic examination of the nasopharynx followed by NBI endoscopy. Biopsies were performed if recurrence was suspected. Results: We identified 32 suspected lesions by endoscopy in WL and/or NBI mode. Scattered brown spots (BS) were identified in 22 patients, and 4 of the 22 who had negative MRI findings were histopathologically confirmed to be neoplasias that were successfully removed via endoscopy. A comparison of the visualization in NBI closer view corresponded to histopathological findings in 22 BS, and the prevalence rates of neoplasias in tail signs, round signs, and irregularities signs were 0% (0/6), 0% (0/7), and 44.4% (4/9), respectively (p = 0.048). The sensitivity, specificity, and diagnostic capability were 37.5%, 92.9% and 0.652 for WL, 87.5%, 74.5% and 0.810 for NBI, and 87.5%, 87.8%, and 0.876 for NBI closer view, respectively. NBI closer view was effective in increasing specificity compared with NBI alone (87.8% vs. 74.5%, p < 0.05), and in increasing sensitivity and diagnostic capability compared to WL alone (87.5% vs. 37.5%, p < 0.05; 0.876 vs. 0.652, p = 0.0001). Conclusions: Although NBI in endoscopy can improve sensitivity of mucosal recurrent nasopharyngeal neoplasias, false-positive (nonneoplasia BS) results may be obtained in areas with nonspecific inflammatory changes due to postradiation effects. NBI closer view not only can offer a timely, convenient, and highly reliable assessment of mucosal recurrent nasopharyngeal carcinoma, it can also make endoscopic removal possible.

Wang, Wen-Hung [Department of Otolaryngology, Chang Gung Memorial Hospital at Chiayi and Chang Gung University College of Medicine, Taiwan (China); Lin, Yen-Chun, E-mail: sarah_travel@hotmail.com [Department of Otolaryngology, Chang Gung Memorial Hospital at Chiayi and Chang Gung University College of Medicine, Taiwan (China); Chen, Wen-Cheng; Chen, Miao-Fen [Department of Radiation Oncology, Chang Gung Memorial Hospital at Chiayi and Chang Gung University College of Medicine, Taiwan (China); Chen, Chih-Cheng [Department of Hematology and Oncology, Chang Gung Memorial Hospital at Chiayi and Chang Gung University College of Medicine, Taiwan (China); Lee, Kam-Fai [Department of Pathology, Chang Gung Memorial Hospital at Chiayi and Chang Gung University College of Medicine, Taiwan (China)

2012-07-15

167

Reversal of Atopic Dermatitis with Narrow-Band UVB Phototherapy and Biomarkers for Therapeutic Response  

PubMed Central

Background Atopic dermatitis (AD) is a common inflammatory skin disease exhibiting a predominantly Th2/“T22” immune activation and a defective epidermal barrier. Narrow-band UVB (NB-UVB) is considered an efficient treatment for moderate-to-severe AD. In psoriasis, NB-UVB has been found to suppress the Th1/Th17-polarization with subsequent reversal of epidermal hyperplasia. The immunomodulatory effects of this treatment are largely unknown in AD. Objective To evaluate the effects of NB-UVB on immune and barrier abnormalities in AD, aiming to establish reversibility of disease and biomarkers of therapeutic response. Methods 12 moderate-to-severe chronic AD patients received NB-UVB phototherapy 3 times weekly for up to 12 weeks. Lesional and non-lesional skin biopsies were obtained before and after treatment and evaluated by gene-expression and immunohistochemistry studies. Results All patients had at least a 50% reduction in SCORing of AD (SCORAD) index with NB-UVB phototherapy. The Th2, “T22,” and Th1 immune pathways were suppressed and measures of epidermal hyperplasia and differentiation normalized. The reversal of disease activity was associated with elimination of inflammatory leukocytes, Th2/“T22”- associated cytokines and chemokines, and normalized expression of barrier proteins. Conclusions Our study shows that resolution of clinical disease in patients with chronic AD is accompanied by reversal of both the epidermal defects and the underlying immune activation. We have defined a set of biomarkers of disease response that associate resolved Th2 and “T22” inflammation in chronic AD patients with reversal of barrier pathology. By showing reversal of the AD epidermal phenotype with a broad immune-targeted therapy, our data argues against a fixed genetic phenotype. PMID:21762976

Tintle, Suzanne; Shemer, Avner; Suárez-Fariñas, Mayte; Fujita, Hideki; Gilleaudeau, Patricia; Sullivan-Whalen, Mary; Johnson-Huang, Leanne; Chiricozzi, Andrea; Cardinale, Irma; Duan, Shenghui; Bowcock, Anne; Krueger, James G.; Guttman-Yassky, Emma

2012-01-01

168

Narrow-band Imager for Multi-Application Solar Telescope (MAST) at Udaipur Solar Observatory  

NASA Astrophysics Data System (ADS)

Multi-Application Solar Telescope (MAST) is an off-axis Gregorian solar telescope of 50 cm clear aperture installed at the lake site of Udaipur solar observatory (USO). A narrow band imager is being developed for near simultaneous observations of the solar atmosphere at different heights. The heart of the system is two Fabry-Perot (FP) etalons working in tandem. The substrate of the etalons is made of Lithium Niobate electro-optic crystal. The filter is tuned by changing the refractive index of the crystal with the application of the voltage. It is important to know the voltage required per unit wavelength shift to tune the system for different wavelength regions for near simultaneous observations. A littrow spectrograph was set up to calibrate the FP etalons. The achieved spectral resolution with the spectrograph at 6173 Å is 35 mÅ. Calibration is carried-out for the Fe I 6173 Å, H-alpha 6563 Å and Ca K 8542 Å. Free spectral range (FSR) obtained for FP1 and FP2 in tandem for 6173 Å is 6.7Å and 150 mÅ respectively. Voltage range of the system allows us to scan the entire line profile of 6173 in the range of ±220 mÅ with a sampling of 20 mÅ. We also performed temperature tuning and voltage tuning of the system. Similar exercise is performed for other two wavelengths. Here we present the details of the calibration set-up and obtained parameters and first-light results of the system.

Raja Bayanna, A.; Mathew, Shibu K.; Venkatakrishnan, Parameswaran; Srivastava, Nandita

2013-04-01

169

NARROW-BAND ULTRA-LOW CURRENT MEASUREMENTS WITH A RF SQUID F. Bordoni, P. Carelli , I. Modena and G.L. Roman!  

E-print Network

NARROW-BAND ULTRA-LOW CURRENT MEASUREMENTS WITH A RF SQUID F. Bordoni, P. Carelli , I. Modena and G at a fixed frequency we inserted a tuning capacitor in the input circuit. However, due to the high value Nb wire. One Fig. 1 : Schematic of the experimental arrangement used for narrow-band ultra

Paris-Sud XI, Université de

170

Destruction of superconductivity in the narrow-band metal K3C60 Susan K. Watson, Kimberly Allen, D. W. Denlinger, and F. Hellman  

E-print Network

Destruction of superconductivity in the narrow-band metal K3C60 Susan K. Watson, Kimberly Allen, D is a consequence of the narrow conduction band and low electron density in K3C60 , which gives rise to an extreme 24 October 1996 Transport data on K3C60 prepared with different amounts of disorder are presented

Hellman, Frances

171

AVHRR Surface Temperature and Narrow-Band Albedo Comparison with Ground Measurements for the Greenland Ice Sheet  

NASA Technical Reports Server (NTRS)

An ice-surface temperature retrieval algorithm for the Greenland ice sheet was developed using NOAA 11 thermal radiances from channels 4 and 5. Temperature, pressure and humidity profiles, cloud observations and skin temperatures from the Swiss Federal Institute of Technology (ETH) camp, located at the equilibrium line altitude at 49 deg17 min W, 69 deg 34 min N, were used in the LOWTRAN 7 model. Through a statistical analysis of daily clear sky profiles, the coefficients that correct for the atmospheric effects were determined for the ETH-Camp field season (May to August). Surface temperatures retrieved by this method were then compared against the in situ observations with a maximum difference of 0.6 K. The NOAA 11 narrow-band planetary albedo values for channels 1 and 2 were calculated using pre-launch calibration coefficients. Scattering and absorption by the atmosphere were modelled with LOWTRAN 7. Then, narrow-band albedo values for the AVHRR visible and near infrared channels were compared with in situ high resolution spectral reflectance measurements. In the visible band (580-680 nm), AVHRR-derived narrow-band albedo and the in situ measurements corrected with radiative transfer model LOWTRAN 7 showed a difference of less than 2%. For the near infrared channel (725-1100 nm) the difference between the measured and modelled narrow-band albedo was 14%. These discrepancies could be either the result of inaccurate aerosol scattering modelling (lack of the in situ observation), or the result of sensor drift due to degradation.

Haefliger, M.; Steffen, K.; Fowler, C.

1993-01-01

172

L-band circular polarization microstrip antenna based on the narrow-slot fractal method  

Microsoft Academic Search

The resonant frequencies of traditional Koch island fractal patch antennas and their narrow-slot counterparts are investigated. The simulation shows that at the stage of higher than the first iteration, the narrow-slot fractal patch antenna has a better effect in decreasing the resonant frequency and reducing the antenna dimension, and this is partly due to its higher performance in increasing the

Nanbo Jin; Mingyan Fan; Xuexia Zhang

2003-01-01

173

On unusual narrow transmission bands for a multi-layered periodic structure containing left-handed materials  

E-print Network

A multi-layered structure consisting of alternate right-handed material (RHM) and left-handed material (LHM)is considered and the unusual narrow transmission bands are explained as the competitive results of the Bragg condition and the transparent condition. These unusual narrow transmission bands may exist regardless whether the optical length of the LHM layer cancels the optical length of the RHM layer or not. This unusual transmission property may disappear when the reflection coefficient for each interface is small and the optical length of the LHM layer does not cancel the optical length of the RHM layer. An non-ideal model when the LHM is dispersive and lossy is also employed to confirm the unusual transmission phenomenon.

Liang Wu; Sailing He; Long Chen

2002-11-03

174

Acne phototherapy with a high-intensity, enhanced, narrow- band, blue light source: an open study and in vitro investigation  

Microsoft Academic Search

The purpose of this study was to investigate the efficacy of phototherapy with a newly-developed high-intensity, enhanced, narrow-band, blue light source in patients with mild to moderate acne. An open study was performed in acne patients who were treated twice a week up to 5 weeks. Acne lesions were reduced by 64%. Two patients experienced dryness. No patient discontinued treatment

Akira Kawada; Yoshinori Aragane; Hiroko Kameyama; Yoshiko Sangen; Tadashi Tezuka

175

Dynamics of a narrow-band exciton coupled with optical phonons: A time-convolutionless master-equation approach  

Microsoft Academic Search

A time-convolutionless master equation is established for studying the dynamics of a narrow-band exciton coupled with optical phonons. Within the nonadiabatic weak-coupling limit, the diagonal hypothesis works quite well so that the exciton-phonon dynamics is mainly governed by the so-called time-dependent dephasing function. It has been shown that the dephasing function tends to zero by exhibiting damped oscillations that characterize

Vincent Pouthier

2009-01-01

176

Teleradiology via narrow-band integrated services digital network (N-ISDN) and Joint Photographic Experts Group (JPEG) Image Compression  

Microsoft Academic Search

The importance of remote access to both radiological images and medical information has stimulated many demonstration projects\\u000a that use a variety of telecommunications providers' offerings. Teleradiology, through modest cost channels, can achieve adequate\\u000a response times using a combination of narrow-band integrated services digital network (N-ISDN) and data compression. A demonstration\\u000a project, developed in collaboration with Southwestern Bell Technology Resources, Inc,

G. James Blaine; Stephen M. Moore; Jerome R. Cox; Robert A. Whitman

1992-01-01

177

Structure investigation of narrow banded spherulites in polyhydroxyalkanoates by microbeam X-ray diffraction with synchrotron radiation  

Microsoft Academic Search

Narrow banded structures of spherulites of poly[(R)-3-hydroxybutyrate] (P(3HB)) and its copolymers, with different second monomer unit of 4-hydroxybutyrate, 3-hydroxyhexanoate or 6-hydroxyhexanoate, were investigated by microbeam X-ray diffraction with Fresnel Zone Plate technique in synchrotron radiation (SPring-8). Radial scanning of spherulites were performed in 2 or 4?m steps with 0.5?m beam diameter of fine microfocus beam. The X-ray diffraction patterns for

Toshihisa Tanaka; Masahiro Fujita; Akihisa Takeuchi; Yoshio Suzuki; Kentaro Uesugi; Yoshiharu Doi; Tadahisa Iwata

2005-01-01

178

Band limited emission with central frequency around 2 Hz accompanying powerful cyclones  

NASA Technical Reports Server (NTRS)

It has been found that powerful cyclones are proceeded, accompanied and followed by narrow band electromagnetic emission with central frequency around 2 Hz. It is shown that the signal from this emission is unique and clearly distinguishable from known types of magnetic pulsations, spectra of local thunderstorms, and signals from industrial sources. This emission was first observed during an unusually powerful cyclone with tornadoes in the western European part of the Soviet Union, which passed by the observatory of Borok from south to north-east. The emission has been confirmed by analysis of similar events in Antarctica. The phenomenon described presents a new aspect of interactions of processes in the lower atmosphere and the ionosphere.

Troitskaia, V. A.; Shepetnov, K. S.; Dvobnia, B. D.

1992-01-01

179

Narrow-band imaging with magnifying endoscopy is accurate for detecting gastric intestinal metaplasia  

PubMed Central

AIM: To investigate the predictive value of narrow-band imaging with magnifying endoscopy (NBI-ME) for identifying gastric intestinal metaplasia (GIM) in unselected patients. METHODS: We prospectively evaluated consecutive patients undergoing upper endoscopy for various indications, such as epigastric discomfort/pain, anaemia, gastro-oesophageal reflux disease, suspicion of peptic ulcer disease, or chronic liver diseases. Patients underwent NBI-ME, which was performed by three blinded, experienced endoscopists. In addition, five biopsies (2 antrum, 1 angulus, and 2 corpus) were taken and examined by two pathologists unaware of the endoscopic findings to determine the presence or absence of GIM. The correlation between light blue crest (LBC) appearance and histology was measured. Moreover, we quantified the degree of LBC appearance as less than 20% (+), 20%-80% (++) and more than 80% (+++) of an image field, and the semiquantitative evaluation of LBC appearance was correlated with IM percentage from the histological findings. RESULTS: We enrolled 100 (58 F/42 M) patients who were mainly referred for gastro-esophageal reflux disease/dyspepsia (46%), cancer screening/anaemia (34%), chronic liver disease (9%), and suspected celiac disease (6%); the remaining patients were referred for other indications. The prevalence of Helicobacter pylori (H. pylori) infection detected from the biopsies was 31%, while 67% of the patients used proton pump inhibitors. LBCs were found in the antrum of 33 patients (33%); 20 of the cases were classified as LBC+, 9 as LBC++, and 4 as LBC+++. LBCs were found in the gastric body of 6 patients (6%), with 5 of them also having LBCs in the antrum. The correlation between the appearance of LBCs and histological GIM was good, with a sensitivity of 80% (95%CI: 67-92), a specificity of 96% (95%CI: 93-99), a positive predictive value of 84% (95%CI: 73-96), a negative predictive value of 95% (95%CI: 92-98), and an accuracy of 93% (95%CI: 90-97). The NBI-ME examination overlooked GIM in 8 cases, but the GIM was less than 5% in 7 of the cases. Moreover, in the 6 false positive cases, the histological examination showed the presence of reactive gastropathy (4 cases) or H. pylori active chronic gastritis (2 cases). The semiquantitative correlation between the rate of LBC appearance and the percentage of GIM was 79% (P < 0.01). CONCLUSION: NBI-ME achieved good sensitivity and specificity in recognising GIM in an unselected population. In routine clinical practice, this technique can reliably target gastric biopsies. PMID:23674874

Savarino, Edoardo; Corbo, Marina; Dulbecco, Pietro; Gemignani, Lorenzo; Giambruno, Elisa; Mastracci, Luca; Grillo, Federica; Savarino, Vincenzo

2013-01-01

180

A Deep ROSAT Survey - X. X-ray-luminous narrow-emission-line galaxies  

Microsoft Academic Search

X-ray luminous narrow-emission-line galaxies (NELGs) have been previously identified and proposed as an important class of extragalactic X-ray source, with a potentially significant contribution to the total extragalactic X-ray flux at energies below ~10 keV. In order to investigate and clarify this possibility, we have used a sample of NELGs found in five deep ROSAT fields, and similar samples belonging

R. E. Griffiths; R. della Ceca; Ioannis Georgantopoulos; B. J. Boyle; G. C. Stewart; Tom Shanks; Antonella Fruscione

1996-01-01

181

Broad-band transmission spectrum and K-band thermal emission of WASP-43b as observed from the ground  

NASA Astrophysics Data System (ADS)

Aims: WASP-43b is the closest-orbiting hot Jupiter, and it has high bulk density. It causes deep eclipse depths in the system's light curve in both transit and occultation that is attributed to the cool temperature and small radius of its host star. We aim to secure a broad-band transmission spectrum and to detect its near-infrared thermal emission in order to characterize its atmosphere. Methods: We observed one transit and one occultation event simultaneously in the g', r', i', z', J, H, K bands using the GROND instrument on the MPG/ESO 2.2-m telescope, where the telescope was heavily defocused in staring mode. After modeling the light curves, we derived wavelength-dependent transit depths and flux ratios and compared them to atmospheric models. Results: From the transit event, we have independently derived WASP-43's system parameters with high precision and improved the period to be 0.81347437(13) days based on all the available timings. No significant variation in transit depths is detected, with the largest deviations coming from the i'-, H-, and K-bands. Given the observational uncertainties, the broad-band transmission spectrum can be explained by either (i) a flat featureless straight line that indicates thick clouds; (ii) synthetic spectra with absorption signatures of atomic Na/K, or molecular TiO/VO that in turn indicate cloud-free atmosphere; or (iii) a Rayleigh scattering profile that indicates high-altitude hazes. From the occultation event, we detected planetary dayside thermal emission in the K-band with a flux ratio of 0.197 ± 0.042%, which confirms previous detections obtained in the 2.09 ?m narrow band and KS-band. The K-band brightness temperature 1878+108-116 K favors an atmosphere with poor day- to nightside heat redistribution. We also have a marginal detection in the i'-band (0.037+0.023-0.021%), corresponding to TB = 2225+139-225 K, which is either a false positive, a signature of non-blackbody radiation at this wavelength, or an indication of reflective hazes at high altitude. Based on observations collected with the Gamma Ray Burst Optical and Near-Infrared Detector (GROND) on the MPG/ESO 2.2-m telescope at La Silla Observatory, Chile. Program 088.A-9016 (PI: Chen).Photometric time series are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/563/A40

Chen, G.; van Boekel, R.; Wang, H.; Nikolov, N.; Fortney, J. J.; Seemann, U.; Wang, W.; Mancini, L.; Henning, Th.

2014-03-01

182

A Novel Technique for Narrow-Band Tunable Filter Photometry to Enable Ground-Based Detection of Earth-Sized Exoplanets  

NASA Astrophysics Data System (ADS)

We present a novel technique for the removal of sky rings from narrow-band photometry, which arise due to atmospheric OH emission. Our goal is to achieve very high-precision ground-based photometry to enable detection of small transit or occultation signals from exoplanets. We demonstrate our technique on narrow-band photometry of the super-Earth-size transiting planet CoRoT-7b acquired with the OSIRIS tunable filter imager on the 10.4-meter Gran Telescopio Canarias. Without removing sky rings, we do not detect a transit of CoRoT-7b at any significance, but after removing sky rings with our technique, we detect a transit at a significance of 3.2-sigma. Our detection of the transit suggests that this technique can enable ground-based detection of exoplanets with transit or occultation depths on the order of 0.1 mmag. At the time of writing, we believe this to be the first ground-based detection of a transit of a super-Earth orbiting a Sun-like star. This implies that the characterization of Earth-sized planets discovered by space-based missions like Kepler and the future TESS mission may be possible from the ground.

Kimock, Benjamin; Colón, Knicole; Pepper, Joshua

2015-01-01

183

Clinicopathological features of narrow-band imaging endoscopy and immunohistochemistry in ultraminute esophageal squamous neoplasms.  

PubMed

To reveal clinicopathological features of narrow-band imaging (NBI) endoscopy and immunohistochemistry in ultraminute esophageal squamous neoplasms. If a lesion diameter was smaller or same compared with a width of closed biopsy forceps, a lesion was defined to be an ultraminute lesion. Twenty-five consecutive patients with 33 ultraminute esophageal lesions that were removed by endoscopic mucosal resection were included in the present study. We conducted two questionnaire surveys of six endoscopists by their retrospective review of endoscopic still images. The six endoscopists evaluated the endoscopic findings of the ultraminute lesions on still images taken by conventional white-light imaging endoscopy and non-magnified NBI endoscopy in the first questionnaire, and taken by magnified NBI endoscopy in the second questionnaire. An experienced pathologist who was unaware of any endoscopic findings made histological diagnosis and evaluated immunoexpression of p53 and Ki67. The 33 ultraminute lesions were all determined to be either 11 high-grade intraepithelial neoplasias (HGIENs) or 22 low-grade intraepithelial neoplasias (LGIENs). The tumor diameters were histologically confirmed to be <3?mm. All of the ultraminute tumors were visualized as unstained areas and brownish areas by real-time endoscopy with Lugol dye staining and non-magnified NBI endoscopy, respectively. All of the ultraminute IENs were visualized as brownish areas by real-time non-magnified NBI endoscopy. Three of the 25 patients with the ultraminute IENs (12%) had multiple brownish areas (more than several areas) in the esophagus on real-time non-magnified NBI endoscopy. All of the ultraminute IENs were visualized as unstained areas by real-time Lugol chromoendoscopy. Twenty of the 25 patients (80%) had multiple unstained areas (more than several areas) in the esophagus on real-time Lugol chromoendoscopy. The first questionnaire survey revealed that a significantly higher detection rate of the ultraminute IENs on non-magnified NBI endoscopy images compared with conventional white-light imaging endoscopy ones (100% vs. 72%, respectively: P < 0.0001). The second questionnaire survey revealed that presence rates of any magnified NBI endoscopy findings were not significantly different between HGIENs and LGIENs. Proliferation, dilation, and various shapes of intrapapillary capillary loops indicated remarkably high presence rates of more than 90% in both HGIENs and LGIENs. Six of 22 LGIENs (27%) and 3 of 11 HGIENs (27%) show a positive expression for p53. None of peri-IEN epithelia was positive for p53. A mean of Ki67 labeling index of LGIENs was 33% and that of HGIENs 36%. Ki67 labeling index was significantly greater in the LGIENs and HGIENs compared with that in the peri-IEN epithelia. There were no significant differences in p53 expression and Ki67 labeling index between the HGIENs and LGIENs. Non-magnified/magnified NBI endoscopy could facilitate visualization and characterization of ultraminute esophageal squamous IENs. The ultraminute HGIENs and LGIENs might have comparable features of magnified NBI endoscopy and immunohistochemistry. PMID:23796261

Goda, K; Dobashi, A; Yoshimura, N; Chiba, M; Fukuda, A; Nakao, Y; Ohya, T R; Sasaki, Y; Kato, M; Aihara, H; Sumiyama, K; Toyoizumi, H; Kato, T; Tajiri, H; Ikegami, M

2014-04-01

184

Narrow-band FM system for television links: Interference between FM and AM television signals  

Microsoft Academic Search

The Band V FM television links used for television outside broadcasts have suffered more and more from interference as the network of UHF television broadcasting transmitters has expanded. There is also thought to be an increasing danger that Band V Links will cause interference to broadcast television reception. Experimental work was carried out to determine whether reducing the bandwidth of

N. H. C. Gilchrist; A. G. Lyner

1978-01-01

185

Volume 35, number 3 OPTICSCOMMUNICATIONS December 1980 NARROW-BAND UV RADIATION (250-260 nm)  

E-print Network

an intracavity- doubled cw ring dye laser. This work not only extends the wavelength range available from second, but this has been accomplish- ed using pulsed dye laser systems whose theoretical bandwidth is at best the Fourier transform limit of the laser pulse duration [2]. For narrower bandwidths cw operation is necessary

Zare, Richard N.

186

ALEXIS (Array of Low-Energy X-Ray Imaging Sensors): A narrow-band survey/monitor of the ultrasoft x-ray sky  

SciTech Connect

Los Alamos and Sandia National Laboratories are building an ultrasoft X-ray monitor experiment. This experiment, called ALEXIS (Array of Low-Energy X-Ray Imaging Sensors), consists of six compact normal-incidence telescopes. ALEXIS will operate in the range 70--110 eV. The ultrasoft X-ray/EUV band is nearly uncharted territory for astrophysics. ALEXIS, with its wide fields-of-view and well-defined wavelength bands, will complement the upcoming NASA Extreme Ultraviolet Explorer and ROSAT EUV Wide Field Camera, which are sensitive broad-band survey experiments. The program objectives of ALEXIS are to (1) demonstrate the feasibility of a wide field-of-view, normal incidence ultrasoft X-ray telescope system and (2) to determine ultrasoft X-ray backgrounds in the space environment. As a dividend, ALEXIS will pursue the following scientific objectives: (1) to map the diffuse background, with unprecedented angular resolution, in several emission-line bands, (2) to perform a narrow-band survey of point sources, (3) to search for transient phenomena in the ultrasoft X-ray band, and (4) to provide synoptic monitoring of variable ultrasoft X-ray sources such as cataclysmic variables and flare stars. ALEXIS is designed to be flown on a small autonomous payload carrier (a minisat) that could be launched from any expendable launch vehicle. The experiment weighs 100 pounds, draws 40 watts, and produces 10 kbps of data. It can be flown in any low earth orbit. Onboard data storage allows operation and tracking from a single ground station at Los Alamos. 57 refs., 12 figs.

Priedhorsky, W.C.; Bloch, J.J.; Cordova, F.; Smith, B.W.; Ulibarri, M.; Chavez, J.; Evans, E.; Seigmund, O.H.W.; Marshall, H.; Vallerga, J.

1989-01-01

187

The infrared emission bands. III. Southern IRAS sources.  

PubMed

We present airborne 5-8 micrometers spectra of southern IRAS sources which reveal strong polycyclic aromatic hydrocarbon (PAH) emission features. The good correlation between the bands, in particular the dominant 6.2 and "7.7" micrometers features, strongly imply a common carrier, reinforcing the PAH hypothesis. However, small but detectable spectral variations exist. Planetaries have a distinctly different ratio of I(6.2)/I(7.7) than other nebulae, accompanied by a redward shift in the actual wavelength of the "7.7" micrometers peak. Further, we have detected a new feature, previously predicted from laboratory spectra of PAH molecules, at 5.2 micrometers in many of these sources. Spectra of two rare [WC 10] planetary nebular nuclei indicate a very prominent plateau of emission, linking the 6.2 and 7.7 micrometers bands. Several of our sources show definite evidence for emission structure between 14 and 23 micrometers in their IRAS Low-Resolution Spectral Atlas spectra: we attribute this structure to PAH bands. too. We have defined the "generic" spectrum of emission bands relating the mean intensities of each band to that of the strongest, near 7.7 micrometers. We have added three more planetary or protoplanetary nebulae to our correlation between 7.7 micrometers band intensity and nebular gas phase C/O ratio, namely NGC 6302, HR 4049, and the highly carbon-rich [WC 10] nucleus, CPD--56 degrees 8032. For the latter we have determined a ratio for C/O of approximately 4.8 from IUE observations. The good correlation between the intensity ratio of the "7.7" micrometers feature relative to the far-infrared dust continuum and nebular C/O also supports a carbonaceous carrier for these emission features. PMID:11542167

Cohen, M; Tielens, A G; Bregman, J; Witteborn, F C; Rank, D M; Allamandola, L J; Wooden, D H; de Muizon, M

1989-06-01

188

Imaging chlorophyll fluorescence with an airborne narrow-band multispectral camera for vegetation stress detection  

Microsoft Academic Search

Progress in assessing the feasibility for imaging fluorescence using the O2-A band with 1 nm full-width half-maximum (FWHM) bands centered at 757.5 and 760.5 nm is reported in this paper. Multispectral airborne data was acquired at 150 m above ground level in the thermal, visible and near infrared regions yielding imagery at 15 cm spatial resolution. Simultaneous field experiments conducted in olive, peach, and

P. J. Zarco-Tejada; J. A. J. Berni; L. Suárez; G. Sepulcre-Cantó; F. Morales; J. R. Miller

2009-01-01

189

Angle and polarization independent narrow-band thermal emitter made of metallic disk on SiO2  

NASA Astrophysics Data System (ADS)

It is shown that the metallic disk structure can be used as an efficient narrow-band thermal emitter in the IR region. The absorption spectra of such structure are investigated both theoretically and experimentally. Calculations of thermal radiation properties of the metallic disk show that the metallic disk is a perfect emitter at a specific wavelength, which can be tuned by varying the diameter of the disk. The metallic disk exhibits only one significant localized surface plasmon polariton (LSPP) mode for both TM and TE polarizations simultaneously. The LSPP mode can be tuned by either varying the disk diameter or the spacer (made of SiO2).

Abbas, Mohammed Nadhim; Cheng, Cheng-Wen; Chang, Yia-Chung; Shih, Min-Hsiung; Chen, Hung-Hsin; Lee, Si-Chen

2011-03-01

190

Observation of coherently enhanced tunable narrow-band terahertz transition radiation from a relativistic sub-picosecond electron bunch train  

SciTech Connect

We experimentally demonstrate the production of narrow-band ({delta}f/f{approx_equal}20% at f{approx_equal}0.5THz) transition radiation with tunable frequency over [0.37, 0.86] THz. The radiation is produced as a train of sub-picosecond relativistic electron bunches transits at the vacuum-aluminum interface of an aluminum converter screen. The bunch train is generated via a transverse-to-longitudinal phase space exchange technique. We also show a possible application of modulated beams to extend the dynamical range of a popular bunch length diagnostic technique based on the spectral analysis of coherent radiation.

Piot, P.; Maxwell, T. J. [Northern Illinois Center for Accelerator and Detector Development and Department of Physics, Northern Illinois University, DeKalb, Illinois 60115 (United States); Accelerator Physics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Sun, Y.-E [Accelerator Physics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Ruan, J.; Lumpkin, A. H.; Thurman-Keup, R. [Accelerator Division, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Rihaoui, M. M. [Northern Illinois Center for Accelerator and Detector Development and Department of Physics, Northern Illinois University, DeKalb, Illinois 60115 (United States)

2011-06-27

191

Emission de bandes larges dans ZnSe : cathodoluminescence, thermoluminescence,  

E-print Network

479 Emission de bandes larges dans ZnSe : cathodoluminescence, thermoluminescence, transitions dues aussi les profondeurs des pièges par différentes techniques de thermoluminescence ainsi que les. Introduction. - La thermoluminescence a été depuis longtemps un procédé très usité pour déter- miner les

Paris-Sud XI, Université de

192

Increased conductivities of Cr doped Al2-xCrxO3 powders due to band gap narrowing  

NASA Astrophysics Data System (ADS)

A high Cr content in the synthesized Al2-xCrxO3 materials was achieved via a new synthesis route, the self propagating combustion method, for investigation of the effect of Cr substitution on the electrical, optical band gap and structural characteristics of the modified Al2O3 materials. X-ray diffraction (XRD) results showed that all the samples were pure and that Cr was successfully substituted in the crystal lattice. The cell parameters and volume are linearly dependent on the Cr content. AC impedance spectroscopy results show that conductivity of the Cr doped samples increases exponentially with Cr content. This is attributed to band gap narrowing of the Al2-xCrxO3 powders as obtained from UV-visible spectrophotometric studies.

Badar, Nurhanna; Kamarulzaman, Norlida; Rusdi, Roshidah; Abdul Aziz, Nor Diyana; Kun Fun, Hoong

2014-03-01

193

Assessment of MODIS Thermal Emissive Band On-Orbit Calibration  

NASA Technical Reports Server (NTRS)

Sixteen Moderate Resolution Imaging Spectroradiometer thermal emissive bands (TEBs) cover the wavelength from 3.75 to 14.24 m. TEB calibration uses data collected from the detector responses to the onboard blackbody (BB) and space view. The BB was designed to operate either at a constant temperature for detector linear gain calibration or at temperatures varying from ambient ( 270 K) to 315 K for on-orbit characterization of nonlinear coefficients. In this paper, we assess TEB on-orbit calibration performance in two aspects: One is to review the calibration trending on the orbital, daily, and multiyear timescales, and the other is to analyze the on-orbit calibration radiance uncertainty and its impact on the calibration. The calibration trending confirms the detector response dependence on the instrument temperature. The temperature trending and prelaunch characterization provide the basis for determining the calibration radiance source temperature range and uncertainties. An analytical approach was used to assess the impacts of onboard radiance uncertainties. The BB emission uncertainty, resulting from the temperature measurement error and emissivity uncertainty, causes a calibration uncertainty up to 0.3%, a value decreasing with the band wavelength. The BB nonblackness effect is analyzed and found to be insignificant. For the band with the lowest BB emissivity, the nonblackness affects the calibration radiance by less than 0.08%. The cavity emission uncertainty and the scan-mirror emission uncertainty both cause a less than 0.1% calibration uncertainty. The analysis of the nonlinear calibration coefficient uncertainty shows that its effect on the low Earth-view brightness-temperature range varies by band and is generally insignificant.

Chang, Tiejun; Xiong, Xiaoxiong

2011-01-01

194

Optimized design of a band-pass filter with low frequency and narrow bandwidth  

NASA Astrophysics Data System (ADS)

An underwater metal pipeline detector is designed based on the principle of artificial source electromagnetic detection, which is used for detecting the deeply buried in underwater metal pipes. Narrowband band-pass filter in the receiver can well separate the specific frequency signal from mixed signal which is containing strong noise. Authors deduced the narrowband filter transfer function and simulated in computer, and the detector was applied in instrument prototype. Experiment results show that the error of the center frequency of the band-pass filter is small, and the gain is stable. In conclusion the detector has good performance.

Tian, Biao; Fu, Guo-hong; Liao, Xiu-ying; Cheng, Hui; Li, Guang

2013-10-01

195

Perfect narrow-band absorber based on a monolayer of metallodielectric microspheres  

SciTech Connect

We have studied how two-dimensional arrays of metallodielectric core-shell microspheres on a metal substrate can efficiently absorb infrared electromagnetic radiation in a narrow wavelength range under normal incidence. Our simulations indicate that perfect absorption efficiencies can be achieved for resonance wavelengths. The influence of core-shell microspheres geometry and lattice geometry is studied on absorption properties. For wavelength from 1.2??m to 2.6??m, an optimal combination of sphere and core radius was obtained to provide perfect absorption which can be wavelength adjusted.

Dyachenko, P. N., E-mail: pavel.dyachenko@tuhh.de; Petrov, A. Yu.; Eich, M. [Institute of Optical and Electronic Materials, Hamburg University of Technology, Eissendorfer Strasse 38, 21073 Hamburg (Germany)] [Institute of Optical and Electronic Materials, Hamburg University of Technology, Eissendorfer Strasse 38, 21073 Hamburg (Germany)

2013-11-18

196

Five years of Project META - An all-sky narrow-band radio search for extraterrestrial signals  

NASA Technical Reports Server (NTRS)

We have conducted a five-year search of the northern sky (delta between 30 and 60 deg) for narrow-band radio signals near the 1420 MHz line of neutral hydrogen, and its second harmonic, using an 8.4 x 10 exp 6 channel Fourier spectrometer of 0.05 Hz resolution and 400 kHz instantaneous bandwidth. The observing frequency was corrected both for motions with respect to three astronomical inertial frames, and for the effect of Earth's rotation, which provides a characteristic changing Doppler signature for narrow-band signals of extraterrestrial origin. Among the 6 x 10 exp 13 spectral channels searched, we have found 37 candidate events exceeding the average detection threshold of 1.7 x 10 exp -23 W/sq m, none of which was detected upon reobservation. The strongest of these appear to be dominated by rare processor errors. However, the strongest signals that survive culling for terrestrial interference lie in or near the Galactic plane. We describe the search and candidate events, and set limits on the prevalence of supercivilizations transmitting Doppler-precompensated beacons at H I or its second harmonic. We conclude with recommendations for future searches, based upon these findings, and a description of our next-generation search system.

Horowitz, Paul; Sagan, Carl

1993-01-01

197

Spin-wave dispersion in ferromagnetic semiconductor superlattices and thin films in the narrow-band limit  

NASA Astrophysics Data System (ADS)

Bulk and surface magnetic excitations of the semi-infinite ferromagnetic semiconductor (FMS) superlattices and thin films described by Heisenberg and s-d model are analyzed using the transfer matrix method, developed in our previous work. Results are discussed in the narrow-band limit. The spin-wave frequencies for the semi-infinite narrow-band semiconductors are analyzed in both low- and high-frequency regions. Energies of localized excitations are compared to the bulk and the results of Green function formalism. Depending on the parameters of the system, the surface spin waves appear as "acoustical" and "optical", and there are only some quantitative difference in the high-frequency region, comparing our method and the Green function method. In the framework of the same methodology, bulk and surface magnetic excitations of more complicated superlattices and thin films made of the FMS superlattices are analyzed in terms of dependence of the system parameters. It is shown that the s-d interaction governs the behavior of the systems. Dependence on bulk and surface parameters is discussed.

Pavkov-Hrvojevi?, M.; Panti?, M.; Radoševi?, S.; Rutonjski, M.; Škrinjar, M.; Kapor, D.

2011-09-01

198

A Minimum Parameter Adaptive Approach for Rejecting Multiple Narrow-Band Disturbances  

E-print Network

with Application to Hard Disk Drives Xu Chen, Student Member, IEEE, and Masayoshi Tomizuka, Fellow, IEEE Abstract- quencies. One example is the track-following control in a hard disk drive (HDD) system, where the airflow-band disturbances, disks drives I. Introduction In a modern hard disk drive (HDD), data/information is stored

Mofrad, Mohammad R. K.

199

A narrow-band injection-seeded pulsed titanium:sapphire oscillator-amplifier system with on-line chirp analysis for  

E-print Network

A narrow-band injection-seeded pulsed titanium:sapphire oscillator-amplifier system with on-band tunable injection-seeded pulsed titanium:sapphire laser system has been developed for application in high of Physics. DOI: 10.1063/1.2789690 I. INTRODUCTION Titanium:sapphire Ti:sapphire, Ti:Al2O3 lasers share

200

A manganese-doped polymeric framework of polyoxotitanate nanoclusters with a narrow band gap.  

PubMed

A three-dimensional coordination polymer based on a manganese-doped polyoxotitanate nanocluster, {Ti13Mn4O16[MeC(CH2O)3]4(OEt)12Br4}?, has been synthesized under solvothermal conditions. It is the first framework of doped polyoxotitanate nanoclusters reported in the literature. Compared with anatase, its band gap is reduced from 3.19 to 2.57 eV. PMID:24042234

Chen, Yang; Sokolow, Jesse D; Trzop, Elzbieta; Coppens, Philip

2013-11-21

201

The contribution of interaural intensity differences to the horizontal auditory localization of narrow bands of noise  

NASA Astrophysics Data System (ADS)

Brief bursts of third-octave bands of noise (center frequencies at 0.5, 1.0, 2.0 and 4.0 kHz) and band pass noises with different degrees of low-frequency content (0.5 to 4.0 kHz, 1.0 to 4.0 kHz and 2.0 to 4.0 kHz) were recorded binaurally from 17 different horizontal locations (90 degrees on the left to 90 degrees on the right in 11.25 degree steps) one meter from the ears of an anthropomorphic mannequin (KEMAR) in an anechoic room and a reverberant room. The recorded sounds were processed by attenuating or removing interaural intensity differences and presented to five normally hearing subjects through insert transducers (ER-3A) in a sound- source identification task. The localization accuracy of the subjects for unprocessed signals was similar to that reported in the literature for free-field listening. Auditory localization performance was not significantly degraded by reducing interaural intensity difference cues to 50% of their original value in dB. However, attenuating interaural intensity differences by 100% degraded localization performance by introducing a bias toward the center. The effect was frequency dependent, with no effect for a 0.5 kHz third octave band. Some asymmetries in localization performance were observed. Localization accuracy was similar for signals recorded in a reverberant room as for those recorded in an anechoic room.

Bakke, Matthew H.

202

An analysis of the information dependence between MODIS emissive bands  

NASA Astrophysics Data System (ADS)

Multispectral, hyperspectral and ultraspectral imagers and sounders are increasingly important for atmospheric science and weather forecasting. The recent advent of multipsectral and hyperspectral sensors measuring radiances in the emissive IR are providing valuable new information. This is due to the presence of spectral channels (in some cases micro-channels) which are carefully positioned in and out of absorption lines of CO2, ozone, and water vapor. These spectral bands are used for measuring surface/cloud temperature, atmospheric temperature, Cirrus clouds water vapor, cloud properties/ozone, and cloud top altidude etc. The complexity of the spectral structure wherein the emissive bands have been selected presents challenges for lossless data compression; these are qualitatively different than the challenges offered by the reflective bands. For a hyperspectral sounder such as AIRS, the large number of channels is the principal contributor to data size. We have shown that methods combining clustering and linear models in the spectral channels can be effective for lossless data compression. However, when the number of emissive channels is relatively small compared to the spatial resolution, such as with the 17 emissive channels of MODIS, such techniques are not effective. In previous work the CCNY-NOAA compression group has reported an algorithm which addresses this case by sequential prediction of the spatial image. While that algorithm demonstrated an improved compression ratio over pure JPEG2000 compression, it underperformed optimal compression ratios estimated from entropy. In order to effectively exploit the redundant information in a progressive prediction scheme we must, determine a sequence of bands in which each band has sufficient mutual information with the next band, so that it predicts it well. We will provide a covariance and mutual information based analysis of the pairwise dependence between the bands and compare this with the qualitative expected dependence suggested by a physical analysis. This compression research is managed by Roger Heymann, PE of OSD NOAA NESDIS Engineering, in collaboration with the NOAA NESDIS STAR Research Office through Mitch Goldberg, Tim Schmit, Walter Wolf.

Gottipati, Srikanth; Gladkova, Irina; Grossberg, Michael

2008-08-01

203

Spectrally narrowed leaky waveguide edge emission and transient electrluminescent dynamics of OLEDs  

SciTech Connect

In summary, there are two major research works presented in this dissertation. The first research project (Chapter 4) is spectrally narrowed edge emission from Organic Light Emitting Diodes. The second project (Chapter 5) is about transient electroluminescent dynamics in OLEDs. Chapter 1 is a general introduction of OLEDs. Chapter 2 is a general introduction of organic semiconductor lasers. Chapter 3 is a description of the thermal evaporation method for OLED fabrication. The detail of the first project was presented in Chapter 4. Extremely narrowed spectrum was observed from the edge of OLED devices. A threshold thickness exists, above which the spectrum is narrow, and below which the spectrum is broad. The FWHM of spectrum depends on the material of the organic thin films, the thickness of the organic layers, and length of the OLED device. A superlinear relationship between the output intensity of the edge emission and the length of the device was observed, which is probably due to the misalignment of the device edge and the optical fiber detector. The original motivation of this research is for organic semiconductor laser that hasn't been realized due to the extremely high photon absorption in OLED devices. Although we didn't succeed in fabricating an electrically pumped organic laser diode, we made a comprehensive research in edge emission of OLEDs which provides valuable results in understanding light distribution and propagation in OLED devices. Chapter 5 focuses on the second project. A strong spike was observed at the falling edge of a pulse, and a long tail followed. The spike was due to the recombination of correlated charge pair (CCP) created by trapped carriers in guest molecules of the recombination zone. When the bias was turned off, along with the decreasing of electric field in the device, the electric field induced quenching decreases and the recombination rate of the CCP increases which result in the spike. This research project provides a profound understanding of the EL dynamics of OLED, and the theoretical model can fit and explain the experiment data quite well. For the edge emission, we focused on the spectrum and the relative intensity of the edge emission. In the future, more research can be done on the comparison of the intensity between the total edge emission and the surface emission which will give us a sense what fraction of light was trapped in the device. Micro structures can be integrated into the OLED such as DFB and DBR, the character of edge emission should be very interesting. For the transient spike, the CCP model can give a good explanation. But in the model, the effect of the electric field change is not included, because from the start point (t=0), we assume the mobility of carriers is a constant. If we consider the details of the change of the electric field, then when turning of the bias, the decrease of the electric field results in decrease of the carrier mobility and the dissociation rate. If we can add the electric field effect into the model, the whole theory will be more convincing.

Zhengqing, Gan

2010-05-16

204

A six-pole narrow-band high temperature superconducting filter with wide stop-band response at P-band  

NASA Astrophysics Data System (ADS)

A quarter-wavelength stepped impedance resonator (QWSIR) is proposed for high temperature superconducting (HTS) filter, offering wide stop-band performance. A six-pole P-band HTS filter with QWSIRs was designed and fabricated. The filter has a fractional bandwidth of 0.8% at 516 MHz and shows the lowest spurious frequency at about 2.15 GHz. The measured results of the HTS filter are in good agreement with simulations.

Gong, Liming; Wei, Bin; Zhang, Ying; Zhang, Xiaoping; Guo, Xubo; Zhang, Guoyong; Cao, Bisong

2013-10-01

205

The effect of narrow-band noise maskers on increment detection1  

PubMed Central

It is often assumed that listeners detect an increment in the intensity of a pure tone by detecting an increase in the energy falling within the critical band centered on the signal frequency. A noise masker can be used to limit the use of signal energy falling outside of the critical band, but facets of the noise may impact increment detection beyond this intended purpose. The current study evaluated the impact of envelope fluctuation in a noise masker on thresholds for detection of an increment. Thresholds were obtained for detection of an increment in the intensity of a 0.25- or 4-kHz pedestal in quiet and in the presence of noise of varying bandwidth. Results indicate that thresholds for detection of an increment in the intensity of a pure tone increase with increasing bandwidth for an on-frequency noise masker, but are unchanged by an off-frequency noise masker. Neither a model that includes a modulation-filter-bank analysis of envelope modulation nor a model based on discrimination of spectral patterns can account for all aspects of the observed data. PMID:21110593

Messersmith, Jessica J.; Patra, Harisadhan; Jesteadt, Walt

2010-01-01

206

Large aperture tunable ultra narrow band Fabry-Perot-Bragg filter  

NASA Astrophysics Data System (ADS)

A novel type of filters based on a combination of a Fabry-Perot etalon and a volume Bragg grating is demonstrated. The proposed solid-spaced Fabry-Perot etalon consists of a high quality fused silica window with both faces having identical dielectric mirrors coatings. The transmission of this Fabry-Perot etalon is a discrete channel spectrum consisting of narrow lines (typically a few tens of picometers) which are separated by gaps with constant width defined as the free spectral range (typically between 0.1 and 10 nm). These discrete resonances define the addressable wavelengths. The second element of this complex filter is a volume Bragg grating. This component is obtained by recording of a sinusoidal refractive index modulation into the volume of a photo-thermo-refractive glass plate. Central wavelength of such element can be tuned over several tens of nanometers by rotating the Bragg grating and therefore changing the incidence angle. This element is thus used to select one of the Fabry-Perot resonances and switch between them. We present the features of this filter and two experimental demonstrations of different configurations of Fabry-Perot-Bragg filters combining different Fabry-Perot etalons and volume Bragg gratings. That way, the flexibility of such kind of filters is demonstrated.

Lumeau, Julien; Smirnov, Vadim; Lemarchand, Fabien; Lequime, Michel; Glebov, Leonid B.

2007-02-01

207

Anatomy of the AGN in NGC 5548: the X-ray narrow emission lines  

NASA Astrophysics Data System (ADS)

After a very successful multi-satellite campaign on Mrk 509 in 2009, we conducted a similar campaign on the AGN NGC 5548 in 2013. During the latter the source appeared unusually strongly absorbed in the soft X-rays, and signatures of strong outflows were also present in the UV. While a talk giving an overview of the campaign (PI: J. Kaastra) is also proposed at this conference, we will focus here on the data obtained from the XMM-RGS, resulting in a stacked spectrum of 660 ks. Narrow emission lines, including He-like triplets of Oxygen, Nitrogen and Neon, and radiative recombination (RRC) features dominate this spectrum due to the low soft X-ray continuum flux. All emission features are consistent with having constant flux over our campaign. The O VII triplet has been one focus of our analysis, especially due to unexpected differences of ˜300 km s^{-1} among the measured outflow velocities of its individual lines. The RRCs allow us to directly calculate a temperature of the emitting gas of a few eV (˜10^{4}K), favouring photoionised conditions. We have modelled the emission lines and features using the photoionisation code Cloudy, to attempt to construct a self-consistent picture of the physical environment of the AGN.

Whewell, M.; Branduardi-Raymont, G.; Kaastra, J.; Mehdipour, M.; Bianchi, S.; NGC 5548 Collaboration

2014-07-01

208

Magnifying Endoscopy with Narrow Band Imaging to Determine the Extent of Resection in Transoral Robotic Surgery of Oropharyngeal Cancer  

PubMed Central

Transoral robotic surgery (TORS) is a less invasive treatment that is becoming popular all over the world. One of the most important factors for achieving success in TORS is the ability to determine the extent of resection during the procedure as the extent of resection in the laryngopharynx not only affects oncological outcomes but also directly affects swallowing and voice functions. Magnifying endoscopy with narrow band imaging (ME-NBI) is an innovative optical technology that provides high-resolution images and is useful in detecting early superficial pharyngeal cancers, which are difficult to detect by standard endoscopy. A 55-year-old male with superficial oropharyngeal cancer has been successfully treated by combining MB-NBI with TORS and MB-NBI was useful in determining the extent of resection. ME-NBI with TORS will make it possible to achieve a higher ratio of minimally invasive treatment in pharyngeal cancer. PMID:25574412

Tateya, Ichiro; Ishikawa, Seiji; Morita, Shuko; Ito, Hiroyuki; Sakamoto, Tatsunori; Murayama, Toshinori; Kishimoto, Yo; Hayashi, Tomomasa; Funakoshi, Makiko; Hirano, Shigeru; Kitamura, Morimasa; Morita, Mami; Muto, Manabu; Ito, Juichi

2014-01-01

209

On the X-ray Baldwin effect for narrow Fe Kalpha emission line  

E-print Network

Most Active Galactic Nuclei (AGN) exhibit a narrow Fe Kalpha line at ~ 6.4 keV in the X-ray spectra, due to the fluorescent emission from cold material far from the inner accretion disk. Using XMM-Newton observations, Page et al. found that the equivalent width (EW) of the narrow Fe Kalpha line decreases with increasing luminosity (EW ~ L^-0.17pm0.08), suggesting a decrease in the covering factor of the material emitting the line (presumably the torus). By combining the archival Chandra HETG observations of 34 type 1 AGNs with XMM observations in literature, we build a much large sample with 101 AGNs. We find a similar X-ray Baldwin effect in the sample (EW ~ L^-0.2015pm0.0426), however, we note that the anti-correlation is dominated by the radio loud AGN in the sample, whose X-ray spectra might be contaminated by the relativistic jet. Excluding the radio loud AGN, we find a much weaker anti-correlation (EW ~ L^-0.1019pm0.0524). We present Monte-Carlo simulations showing that such a weak anti-correlation can be attributed to the relative short time scale variations of the X-ray continuum.

P. Jiang; J. X. Wang; T. G. Wang

2006-03-14

210

A Search for Low Surface Brightness Structure Around Compact Narrow Emission Line Galaxies  

E-print Network

As the most extreme members of the rapidly evolving faint blue galaxy population at intermediate redshift, the compact narrow emission line galaxies (CNELGs) are intrinsically luminous (-22 -18). Conversely, 15 are not blue enough to fade to low-luminosity dwarfs (M_B > -15.2). The majority of the CNELGs are consistent with progenitors of intermediate-luminosity dwarfs and low-luminosity spiral galaxies with small disks. CNELGs are a heterogeneous progenitor population with significant fractions (up to 44%) capable of fading into today's faint dwarfs (M_B > -15.2), while 15 to 85% may only experience an apparently extremely compact CNELG phase at intermediate redshift but remain more luminous galaxies at the present epoch.

Elizabeth J. Barton; Liese van Zee; Matthew A. Bershady

2006-10-27

211

Molecular nitrogen LBH band system far-UV emissions of sprite streamers  

E-print Network

Molecular nitrogen LBH band system far-UV emissions of sprite streamers Ningyu Liu and Victor P due to N2 Lyman-Birge- Hopfield (LBH) band system. Modeling results indicate that the LBH emissions., and V. P. Pasko (2005), Molecular nitrogen LBH band system far-UV emissions of sprite streamers, Geophys

Pasko, Victor

212

Search algorithm for the detection of long-duration narrow-band transients in GW interferometers  

NASA Astrophysics Data System (ADS)

The recent observation of quasi-periodic oscillations (QPOs) in the x-ray light curve of soft gamma-ray repeaters, which fall within LIGO's sensitivity band, prompted us to search for gravitational waves associated with them. We describe the corresponding search algorithm that is based on the energy measurement in a single detector signal stream. We analytically derive the search sensitivity and compare it to the numerical sensitivity provided by the analysis pipeline with simulated detector noise. We found excellent agreement between the two approaches, reassuring us that the analysis method is well understood and implemented properly. The detector noise is approximated as white Gaussian with a strain equivalent spectral noise density of 10-22 strain Hz-1/2, similar to the noise floor of the H1 LIGO detector at the time of the SGR 1806 20 hyperflare event of 27 December 2004. As a trial model, we use a hypothetical 100 Hz QPO lasting for 50s. The corresponding energy sensitivity is found to be Esens = 3.63 × 10-43 strain2 Hz-1 which, in terms of amplitude, is hsensrss-det = 6.06 × 10-22 strain Hz-1/2. We show that, besides being simple and flexible, the algorithm is sensitive to a wide range of waveforms obeying the time and bandwidth requirements.

Matone, L.; Márka, S.

2007-10-01

213

Compact, narrow-linewidth, tunable ultraviolet laser source for detecting Hg emissions  

NASA Astrophysics Data System (ADS)

Recent EPA regulations targeting mercury (Hg) emissions from utility coal boilers have prompted increased activity in the development of reliable chemical sensors for monitoring Hg emissions with high sensitivity, high specificity, and fast time response. We are developing a portable, laser-based instrument for real-time, stand-off detection of Hg emissions that involves exciting the Hg (6 3P I <--6 1S 0) transition at 253.7 nm and detecting the resulting resonant emission from Hg (6 3P I). The laser for this approach must be tunable over the Hg absorption line at 253.7 nm, while system performance modeling has indicated a desired output pulse energy >=0.1 ?J and linewidth <=5 GHz (full width at half-maximum, FWHM). In addition, the laser must have the requisite physical characteristics for use in coal-fired power plants. To meet these criteria, we are pursing a multistage frequency-conversion scheme involving an optical parametric amplifier (OPA). The OPA is pumped by the frequency-doubled output of a passively Q-switched, monolithic Nd:YAG micro-laser operating at 10-Hz repetition rate and is seeded by a 761-nm, cw distributed-feedback diode laser. The resultant pulse-amplified seed beam is frequency tripled in two nonlinear frequency-conversion steps to generate 253.7-nm light. The laser system is mounted on a 45.7 cm × 30.5 cm breadboard and can be further condensed using custom optical mounts. Based on simulations of the nonlinear frequency-conversion processes and current results, we expect this laser architecture to exceed the desired pulse energy. Moreover, this approach provides a compact, all-solid- state source of tunable, narrow-linewidth visible and ultraviolet radiation, which is required for many chemical sensing applications.

Hoops, Alexandra A.; Farrow, Roger L.; Schulz, Paul; Reichardt, Thomas A.; Bambha, Ray P.; Schmitt, Randal L.; Kliner, Dahv A. V.

2008-02-01

214

Methane Band and Continuum Band Imaging of Titan's Atmosphere Using Cassini ISS Narrow Angle Camera Pictures from the CURE/Cassini Imaging Project  

NASA Astrophysics Data System (ADS)

The study of Titan's atmosphere, which bears resemblance to early Earth's, may help us understand more of our own. Constructing a Monte Carlo model of Titan's atmosphere is helpful to achieve this goal. Methane (MT) and continuum band (CB) images of Titan taken by the CURE/Cassini Imaging Project, using the Cassini Narrow Angle Camera (NAC) were analyzed. They were scheduled by Cassini Optical Navigation. Images were obtained at phase 53°, 112°, 161°, and 165°. They include 22 total MT1(center wavelength at 619nm), MT2(727nm), MT3(889nm), CB1(635nm), CB2(751nm), and CB3(938nm) images. They were reduced with previously written scripts using the National Optical Astronomy Observatory Image Reduction and Analysis Facility scientific analysis suite. Correction for horizontal and vertical banding and cosmic ray hits were made. The MT images were registered with corresponding CB images to ensure that subsequently measured fluxes ratios came from the same parts of the atmosphere. Preliminary DN limb-to-limb scans and loci of the haze layers will be presented. Accurate estimates of the sub-spacecraft points on each picture will be presented. Flux ratios (FMT/FCB=Q0) along the scans and total absorption coefficients along the lines of sight from the spacecraft through the pixels (and into Titan) will also be presented.

Shitanishi, Jennifer; Gillam, S. D.

2009-05-01

215

High-frequency response and the possibilities of frequency-tunable narrow-band terahertz amplification in resonant tunneling nanostructures  

SciTech Connect

The characteristics of the high-frequency response of single- and double-well resonant tunneling structures in a dc electric field are investigated on the basis of the numerical solution of a time-dependent Schroedinger equation with open boundary conditions. The frequency dependence of the real part of high frequency conductivity (high-frequency response) in In{sub 0.53}Ga{sub 0.47}As/AlAs/InP structures is analyzed in detail for various values of the dc voltage V{sub dc} in the negative differential resistance (NDR) region. It is shown that double-well three-barrier structures are promising for the design of terahertz-band oscillators. The presence of two resonant states with close energies in such structures leads to a resonant (in frequency) response whose frequency is determined by the energy difference between these levels and can be controlled by varying the parameters of the structure. It is shown that, in principle, such structures admit narrow-band amplification, tuning of the amplification frequency, and a fine control of the amplification (oscillation) frequency in a wide range of terahertz frequencies by varying a dc electric voltage applied to the structure. Starting from a certain width of the central intermediate barrier in double-well structures, one can observe a collapse of resonances, where the structure behaves like a single-well system. This phenomenon imposes a lower limit on the oscillation frequency in three-barrier resonant tunneling structures.

Kapaev, V. V., E-mail: kapaev@sci.lebedev.ru; Kopaev, Yu. V.; Savinov, S. A.; Murzin, V. N. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)] [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

2013-03-15

216

Precise photometric redshifts with a narrow-band filter set: The PAU Survey at the William Herschel Telescope  

E-print Network

The Physics of the Accelerating Universe (PAU) survey at the William Herschel Telescope (WHT) will use a new optical camera (PAUCam) with a large set of narrow-band filters to perform a photometric galaxy survey with a quasi-spectroscopic redshift precision of \\sigma(z)/(1 + z) ~ 0.0035 and map the large-scale structure of the universe in three dimensions up to i_AB < 22.5-23.0. In this paper we present a detailed photo-z performance study using photometric simulations for 40 equally-spaced 12.5-nm-wide (FWHM) filters with a ~25% overlap and spanning the wavelength range from 450 nm to 850 nm, together with a ugrizY broad-band filter system. We then present the migration matrix r_ij, containing the probability that a galaxy in a true redshift bin j is measured in a photo-z bin i, and study its effect on the determination of galaxy auto- and cross-correlations. Finally, we also study the impact on the photo-z performance of small variations of the filter set in terms of width, wavelength coverage, etc., and...

Martí, Pol; Castander, Francisco J; Gaztañaga, Enrique; Eriksen, Martin; Sánchez, Carles

2014-01-01

217

Precise photometric redshifts with a narrow-band filter set: the PAU survey at the William Herschel Telescope  

NASA Astrophysics Data System (ADS)

The Physics of the Accelerating Universe (PAU) survey at the William Herschel Telescope will use a new optical camera (PAUCam) with a large set of narrow-band filters to perform a photometric galaxy survey with a quasi-spectroscopic redshift precision of ?(z)/(1 + z) ˜ 0.0035 and map the large-scale structure of the universe in three dimensions up to iAB < 22.5-23.0. In this paper, we present a detailed photo-z performance study using photometric simulations for 40 equally spaced 12.5-nm-wide (full width at half-maximum) filters with an ˜25 per cent overlap and spanning the wavelength range from 450 to 850 nm, together with a ugrizY broad-band filter system. We then present the migration matrix rij, containing the probability that a galaxy in a true redshift bin j is measured in a photo-z bin i, and study its effect on the determination of galaxy auto- and cross-correlations. Finally, we also study the impact on the photo-z performance of small variations of the filter set in terms of width, wavelength coverage, etc., and find a broad region where slightly modified filter sets provide similar results, with the original set being close to optimal.

Martí, P.; Miquel, R.; Castander, F. J.; Gaztañaga, E.; Eriksen, M.; Sánchez, C.

2014-07-01

218

Are PAH molecules the carriers of Unidentified Infrared Emission bands?  

NASA Astrophysics Data System (ADS)

Polycyclic aromatic hydrocarbon (PAH) molecules are widely considered as the preferred candidate for the carrier of the unidentified infrared emission bands observed in the interstellar medium and circumstellar envelopes. In this paper we report the result of fitting a variety of non-PAH spectra (silicates, hydrogenated amorphous carbon, coal and even artificial spectra) using the theoretical infrared spectra of PAHs from the NASA Ames PAH IR Spectroscopic Database. We show that these non-PAH spectra can be well fitted by PAH mixtures. This suggest that a general match between astronomical spectra and those of PAH mixtures does not necessarily provide definitive support for the PAH hypothesis.

Kwok, Sun; Zhang, Yong

2015-01-01

219

Eu3+-activated Y2MoO6: a narrow band red-emitting phosphor with strong near-UV absorption.  

PubMed

Near-UV excited narrow line red-emitting phosphors, Eu(3+)-activated Y2MoO6 systems, were synthesized using a simple molten salt reaction. The structure and photoluminescence characteristics were investigated using X-ray powder diffraction, UV-Vis absorption and fluorescent spectrophotometry. The excitation spectra show strong broad-band absorptions in the near-UV to blue light regions which match the radiation of near-UV light-emitting diode chips well. Under excitation of either near-UV or blue light, intense red emission with a main peak of 611 nm is observed, ascribed to the (5)D0-(7)F2 transition of Eu(3+) ions; the optimal doping concentration is 20 mol%. The chromaticity coordinates (x = 0.65, y = 0.34) of the as-obtained phosphor are very close to the National Television Standard Committee standard values (x = 0.67, y = 0.33). All these characteristics suggest that this material is a promising red-emitting phosphor candidate for white-LEDs based on near-UV LED chips. PMID:23124929

He, Xianghong; Bian, Danping; Wang, Hao; Xu, Jian

2013-01-01

220

Narrow-band red-emitting Sr[LiAl?N?]:Eu²? as a next-generation LED-phosphor material.  

PubMed

To facilitate the next generation of high-power white-light-emitting diodes (white LEDs), the discovery of more efficient red-emitting phosphor materials is essential. In this regard, the hardly explored compound class of nitridoaluminates affords a new material with superior luminescence properties. Doped with Eu(2+), Sr[LiAl3N4] emerged as a new high-performance narrow-band red-emitting phosphor material, which can efficiently be excited by GaN-based blue LEDs. Owing to the highly efficient red emission at ?(max) ~ 650 nm with a full-width at half-maximum of ~1,180 cm(-1) (~50 nm) that shows only very low thermal quenching (>95% relative to the quantum efficiency at 200 °C), a prototype phosphor-converted LED (pc-LED), employing Sr[LiAl3N4]:Eu(2+) as the red-emitting component, already shows an increase of 14% in luminous efficacy compared with a commercially available high colour rendering index (CRI) LED, together with an excellent colour rendition (R(a)8 = 91, R9 = 57). Therefore, we predict great potential for industrial applications in high-power white pc-LEDs. PMID:24952748

Pust, Philipp; Weiler, Volker; Hecht, Cora; Tücks, Andreas; Wochnik, Angela S; Henß, Ann-Kathrin; Wiechert, Detlef; Scheu, Christina; Schmidt, Peter J; Schnick, Wolfgang

2014-09-01

221

Narrow-band red-emitting Sr[LiAl3N4]:Eu2+ as a next-generation LED-phosphor material  

NASA Astrophysics Data System (ADS)

To facilitate the next generation of high-power white-light-emitting diodes (white LEDs), the discovery of more efficient red-emitting phosphor materials is essential. In this regard, the hardly explored compound class of nitridoaluminates affords a new material with superior luminescence properties. Doped with Eu2+, Sr[LiAl3N4] emerged as a new high-performance narrow-band red-emitting phosphor material, which can efficiently be excited by GaN-based blue LEDs. Owing to the highly efficient red emission at ?max ~ 650 nm with a full-width at half-maximum of ~1,180 cm-1 (~50 nm) that shows only very low thermal quenching (>95% relative to the quantum efficiency at 200 °C), a prototype phosphor-converted LED (pc-LED), employing Sr[LiAl3N4]:Eu2+ as the red-emitting component, already shows an increase of 14% in luminous efficacy compared with a commercially available high colour rendering index (CRI) LED, together with an excellent colour rendition (Ra8 = 91, R9 = 57). Therefore, we predict great potential for industrial applications in high-power white pc-LEDs.

Pust, Philipp; Weiler, Volker; Hecht, Cora; Tücks, Andreas; Wochnik, Angela S.; Henß, Ann-Kathrin; Wiechert, Detlef; Scheu, Christina; Schmidt, Peter J.; Schnick, Wolfgang

2014-09-01

222

The Irkutsk Barium filter for narrow-band wide-field high-resolution solar images at the Dutch Open Telescope  

E-print Network

1 The Irkutsk Barium filter for narrow-band wide-field high-resolution solar images at the Dutch ABSTRACT A wide-field birefringent filter for the barium II line at 455.4nm is developed in Irkutsk. The Barium line is excellent for Doppler-shift measurements because of low thermal line-broadening and steep

Rutten, Rob

223

A narrow-band wavelength-tunable laser system delivering high-energy 300 ps pulses in the near-infrared  

E-print Network

A narrow-band wavelength-tunable laser system delivering high-energy 300 ps pulses in the near; accepted 30 September 2002 We report on the operation of a novel laser system delivering high-energy pulses, however, the tunability extends over the range 700­970 nm. The laser system is suitable for high

224

Principal resonance responses of SDOF systems with small fractional derivative damping under narrow-band random parametric excitation  

NASA Astrophysics Data System (ADS)

The principal resonance responses of nonlinear single-degree-of-freedom (SDOF) systems with lightly fractional derivative damping of order ? (0 < ? < 1) subject to the narrow-band random parametric excitation are investigated. The method of multiple scales is developed to derive two first order stochastic differential equation of amplitude and phase, and then to examine the influences of fractional order and intensity of random excitation on the first-order and second-order moment. As an example, the stochastic Duffing oscillator with fractional derivative damping is considered. The effects of detuning frequency parameter, the intensity of random excitation and the fractional order derivative damping on stability are studied through the largest Lyapunov exponent. The corresponding theoretical results are well verified through direct numerical simulations. In addition, the phenomenon of stochastic jump is analyzed for parametric principal resonance responses via finite differential method. The stochastic jump phenomena indicates that the most probable motion is around the larger non-trivial branch of the amplitude response when the intensity of excitation is very small, and the probable motion of amplitude responses will move from the larger non-trivial branch to trivial branch with the increasing of the intensity of excitation. Such stochastic jump can be considered as bifurcation.

Liu, Di; Li, Jing; Xu, Yong

2014-10-01

225

Assessment of Gastric Phenotypes Using Magnifying Narrow-Band Imaging for Differentiation of Gastric Carcinomas from Adenomas  

PubMed Central

Background. Conventional white-light endoscopy and forceps biopsy are insufficient for definitive diagnosis of gastric adenoma. Immunohistochemical studies have reported an obvious phenotypic difference between adenomas and carcinomas. We investigated the utility of narrow-band imaging with magnifying endoscopy (NBI-ME) for mucin phenotypic assessment to differentiate carcinomas from adenomas. Methods. NBI-ME findings were classified into A, B, and AB types, which revealed papillary, tubular pits and groove microstructures, respectively. To investigate A-B classifications retrospectively, 137 patients (155 lesions) that were diagnosed pretherapeutically with adenoma or borderline lesions by biopsy were enrolled. The mucin phenotype was analyzed immunohistochemically in the first 60 lesions. Results. After endoscopic submucosal dissection, A type and AB type lesions were determined histologically as carcinoma (81/82, 99%). B type lesions were adenoma (29/73, 40%) and carcinoma (44/73, 60%). A or AB type correlated to histological carcinomas (sensitivity 65%, specificity 97%, and accuracy 71%). Mucin phenotypes were gastric or gastrointestinal in A type and AB type carcinomas (31/37, 84%) and intestinal in B type adenomas and carcinomas (21/23, 91%). Conclusions. NBI-ME has the advantage of the assessment of mucin phenotypes in gastric carcinomas and adenomas. The proposed A-B classification is useful, especially for differentiation of gastric or gastrointestinal carcinomas from adenomas. PMID:25371671

Hashimoto, Satoru; Nishikura, Ken; Mizuno, Ken-Ichi; Takeuchi, Manabu; Ajioka, Yoichi

2014-01-01

226

Data analysis of gravitational-wave signals from spinning neutron stars. V. A narrow-band all-sky search  

SciTech Connect

We present theory and algorithms to perform an all-sky coherent search for periodic signals of gravitational waves in narrow-band data of a detector. Our search is based on a statistic, commonly called the F-statistic, derived from the maximum-likelihood principle in Paper I of this series. We briefly review the response of a ground-based detector to the gravitational-wave signal from a rotating neuron star and the derivation of the F-statistic. We present several algorithms to calculate efficiently this statistic. In particular our algorithms are such that one can take advantage of the speed of fast Fourier transform in calculation of the F-statistic. We construct a grid in the parameter space such that the nodes of the grid coincide with the Fourier frequencies. We present interpolation methods that approximately convert the two integrals in the F-statistic into Fourier transforms so that the fast Fourier transform algorithm can be applied in their evaluation. We have implemented our methods and algorithms into computer codes and we present results of the Monte Carlo simulations performed to test these codes.

Astone, Pia [Istituto Nazionale di Fisica Nucleare, (INFN)-Rome I, 00185 Rome (Italy); Borkowski, Kazimierz M. [Centre for Astronomy, Nicolaus Copernicus University, Gagarina 11, 87-100 Torun (Poland); Jaranowski, Piotr; Pietka, Maciej [Faculty of Physics, University of Bialystok, Lipowa 41, 15-424 Bialystok (Poland); Krolak, Andrzej [Institute of Mathematics, Polish Academy of Sciences, Sniadeckich 8, 00-950 Warsaw (Poland)

2010-07-15

227

Toward Photochemical Water Splitting Using Band-Gap-Narrowed Semiconductors and Transition-Metal Based Molecular Catalysts  

SciTech Connect

We are carrying out coordinated theoretical and experimental studies of toward photochemical water splitting using band-gap-narrowed semiconductors (BGNSCs) with attached multi-electron molecular water oxidation and hydrogen production catalysts. We focus on the coupling between the materials properties and the H{sub 2}O redox chemistry, with an emphasis on attaining a fundamental understanding of the individual elementary steps in the following four processes: (1) Light-harvesting and charge-separation of stable oxide or oxide-derived semiconductors for solar-driven water splitting, including the discovery and characterization of the behavior of such materials at the aqueous interface; (2) The catalysis of the four-electron water oxidation by dinuclear hydroxo transition-metal complexes with quinonoid ligands, and the rational search for improved catalysts; (3) Transfer of the design principles learned from the elucidation of the DuBois-type hydrogenase model catalysts in acetonitrile to the rational design of two-electron hydrogen production catalysts for aqueous solution; (4) Combining these three elements to examine the function of oxidation catalysts on BGNSC photoanode surfaces and hydrogen production catalysts on cathode surfaces at the aqueous interface to understand the challenges to the efficient coupling of the materials functions.

Muckerman,J.T.; Rodriguez, J.A.; Fujita, E.

2009-06-07

228

Clinical impact of narrow-band imaging magnifying endoscopy for 'basal layer type squamous cell carcinoma' in the esophagus.  

PubMed

A 61-year-old man had received endoscopic submucosal dissection (ESD) for early gastric cancer twice. Then he had undergone annual control esophagogastroduodenoscopy using narrow-band imaging (NBI) magnifying endoscope. At the esophagogastroduodenoscopy, we were not able to detect any significant finding in the esophagus by conventional endoscopy. Switching to NBI mode, a brownish area was showed in the middle esophagus. The lesion showing the brownish area was predicted to be mucosal squamous cell carcinoma (SCC) as a result of assessment of morphologic change of intraepithelial papillary capillary loop under magnifying NBI observation. Lugol chromoendoscopy displayed the lesion as unstained area corresponding to the brownish area visualized by NBI. The ESD was performed for the lesion. Histology from ESD specimen showed SCC with minimal invasion to lamina propria at multifocal sites. The SCC was surrounded by low-grade intraepithelial neoplasia. Most of the SCC showed a high degree of cytological and architectural atypia confined to the lower half of the epithelium. The type of SCC was called as 'basal layer type SCC' mainly by Japanese pathologists. We suggest that magnifying NBI endoscopy can be useful for detecting and diagnosing 'basal layer type SCC'. PMID:21535206

Goda, Kenichi; Tajiri, Hisao; Ikegami, Masahiro; Dobashi, Akira; Yoshimura, Noboru

2011-05-01

229

Endoscopic Detection of Early Esophageal Squamous Cell Carcinoma in Patients with Achalasia: Narrow-Band Imaging versus Lugol's Staining.  

PubMed

Chromoendoscopy with Lugol's staining remains the gold standard technique for detecting superficial SCC. An alternative technique, such as narrow-band imaging (NBI), for "optical staining" would be desirable, since NBI is a simpler technique and has no known complications. In this study, we compare NBI without magnification and chromoendoscopy with Lugol's staining for detecting high-grade dysplasia and intramucosal esophageal squamous cell carcinoma (SCC) in patients with achalasia. This was a prospective observational study of 43 patients with achalasia referred to the Gastrointestinal Endoscopy Unit of the Hospital of Clinics, São Paulo, University Medical School, Brazil, from October 2006 to February 2007. Conventional examinations with white light, NBI, and Lugol staining were consecutively performed, and the suspected lesions were mapped, recorded, and sent for biopsy. The results of the three methods were compared regarding sensitivity, specificity, accuracy, positive predictive value, negative predictive value, positive likelihood value, and negative likelihood value. Of the 43 patients, one was diagnosed with esophageal squamous cell carcinoma, and it was detected by all of the methods. NBI technology without magnification has high sensitivity and negative predictive value for detecting superficial esophageal squamous cell carcinoma, and it has comparable results with those obtained with Lugol's staining. PMID:23935622

Ide, Edson; Carneiro, Fred Olavo Aragão Andrade; Frazão, Mariana Souza Varella; Chaves, Dalton Marques; Sallum, Rubens Antônio Aissar; de Moura, Eduardo Guimarães Hourneaux; Sakai, Paulo; Cecconello, Ivan; Maluf-Filho, Fauze

2013-01-01

230

Oxidation Reduction is a Key Process for Successful Treatment of Psoriasis by Narrow-band UVB Phototherapy.  

PubMed

Narrow-band UVB (NB-UVB) phototherapy is commonly used for treatment of psoriasis, though the mechanisms underlying its efficacy have not been completely elucidated. We used gene expression profiling to characterise gene expression in lesional epidermis from psoriasis patients in the middle and late stages of NB-UVB photo-therapy. Increased melanogenesis gene expression was the earliest response to phototherapy. At the end of treatment, genes responding to phototherapy and correlated to treatment outcome were involved in oxidation reduction, growth and mitochondria organisation. Particularly, SPATA18, a key regulator of mitochondrial quality, was significantly down-regulated in psoriasis (p?

Gu, Xiaolian; Nylander, Elisabet; Coates, Philip J; Nylander, Karin

2015-01-15

231

Dynamics of a narrow-band exciton coupled with optical phonons: A time-convolutionless master-equation approach  

NASA Astrophysics Data System (ADS)

A time-convolutionless master equation is established for studying the dynamics of a narrow-band exciton coupled with optical phonons. Within the nonadiabatic weak-coupling limit, the diagonal hypothesis works quite well so that the exciton-phonon dynamics is mainly governed by the so-called time-dependent dephasing function. It has been shown that the dephasing function tends to zero by exhibiting damped oscillations that characterize a series of dephasing-rephasing mechanisms. Indeed, the correlation time of the exciton-phonon interaction is defined as the time needed to the exciton to cover a few lattice sites. Therefore this correlation time is sufficiently long so that the system dynamics remains sensitive to the coherent nature of the lattice vibrations. Because the phonon memory recurs periodically, the exciton experiences a series of dephasing-rephasing processes. Although each rephasing does not exactly compensate the previous dephasing, the coherence survives. Consequently, the exciton keeps its wavelike nature and a coherent energy transfer occurs according to an effective hopping constant smaller than the bare hopping constant.

Pouthier, Vincent

2009-10-01

232

Identifying AGN Balmer absorptions and stratified narrow emission-line region kinematics in SDSS J112611.63+425246.4  

NASA Astrophysics Data System (ADS)

Context. Balmer absorption is a rare phenomenon in active galactic nuclei (AGNs). So far, only seven Balmer-absorption AGNs have been reported in the literature. Aims: We here report the identification of SDSS J112611.63+425246 as a new Balmer-absorption AGN through our spectral analysis and study the kinematics of its narrow emission-line region (NLR). Methods: We modeled the continuum by a linear combination of a starlight component, a power law from the central AGN, and the emission from the FeII complex. After subtracting the modeled continuum, each emission or absorption line profile is a sum of multi-Gaussian functions. All the line shifts were determined with respect to the modeled starlight component. Results: By using the host starlight as a reference for the local system, both H? and H? show AGN absorptions with a blueshift of ~300 km s-1. We identify a strong anticorrelation between the inferred velocity shifts and the ionization potential for various narrow emission lines, which suggests a stratified NLR kinematics. A de-accelerated outflow is implied for the inner NLR gas, an accelerated inflow for the outer NLR gas. This complicated NLR kinematics additionally implies that AGN narrow emission lines, even for the low-ionized lines, might not be a reliable substitute for the velocity of the local system.

Wang, J.; Xu, D. W.

2015-01-01

233

Narrow-band Imagery with the Goddard Fabry-Perot: Probing the Epoch of Active Accretion for PMS Stars  

NASA Technical Reports Server (NTRS)

The STIS coronagraphic imaging sample of I'MS stars was surveyed with the Goddard Fabry-Perot (GFP) interferometer to determine what fraction of the stars drive jets, whether there is any difference in behavior for a group of intermediate-mass stars as compared with T Tauri stars, and to search for evolutionary effects. Compared to broad band imaging, the FGP achieves an emission-line nebulosity-to-star contrast gain of between 500 and 3000. To date, we have detected jets associated with classical T Tauri stars spanning a factor of 280 in mass accretion rate in approximately 50% of the STIS coronagraphic imaging sample. We also detected jets or Herbig-HARO knots associated with 5 Herbig Ae stars, all younger than 8 Myr, for a detection fraction which is smaller than the T Tauri survey.

Woodgate, Bruce E.; Grady, C.; Endres, M.; Williger, G.

2006-01-01

234

Influence of the surface band structure in photoelectron emission by ultra-short laser pulses  

NASA Astrophysics Data System (ADS)

Photoelectron emission from the valence band of aluminum and beryllium surfaces by ultra-short laser pulses is studied within the Band-Structure-Based - Volkov (BSB-V) approximation, which takes into account the contribution of the band structure of the solid. We found that band structure effects are extremely important for Be(0001), for which signatures of partially occupied surface states can be observed in the electron emission spectra.

Ríos Rubiano, C. A.; Gravielle, M. S.; Mitnik, D. M.; Silkin, V. M.

2014-04-01

235

Assessment of novel endoscopic techniques for visualizing superficial esophageal squamous cell carcinoma: autofluorescence and narrow-band imaging.  

PubMed

Lugol chromoendoscopy (LCE) is a useful technique for visualizing superficial esophageal squamous cell carcinoma (SESCC), but the stimulating effect of the Lugol solution can sometimes cause clinical problems. Newly developed techniques such as narrow-band imaging (NBI) and autofluorescence imaging (AFI) enable SESCC to be easily visualized without LCE. This study aimed to assess the visualizing power of white-light imaging (WLI), NBI, and AFI, compared with LCE. Sixteen patients with 16 SESCCs underwent LCE and endoscopy with NBI and AFI before endoscopic or surgical treatment. Twenty sets of endoscopic SESCC images were prepared, each of which contained still images from WLI, NBI, AFI, and LCE. The image sets were shown to 25 endoscopists, who then each completed a questionnaire about the ease-of-detection of the SESCCs, scoring WLI, NBI, and AFI images with reference to a perfect score for LCE; mean scores were compared. Overall, significantly higher scores were given for NBI than for WLI and AFI, with no significant difference between WLI and AFI. Stratification by endoscopist characteristics indicated that younger or less experienced endoscopists gave significantly higher scores for AFI than WLI. Stratification by lesion characteristics revealed that AFI had significantly higher scores than WLI for flat/elevated lesions or those with diameter >or=20 mm; scores were significantly lower for depressed lesions or those with diameter <20 mm. For SESCC, the visualizing power of NBI seems more similar to that of LCE than AFI or WLI: NBI might be more useful than AFI or WLI in detecting SESCC. AFI seems to have both superior and inferior visualizing power to WLI depending on characteristics of endoscopists or SESCC lesions. PMID:19191860

Yoshida, Y; Goda, K; Tajiri, H; Urashima, M; Yoshimura, N; Kato, T

2009-01-01

236

Measurements of global UV irradiance at Terranova Bay, Antactica, by a home made narrow band filter radiometer  

NASA Astrophysics Data System (ADS)

Filter radiometers measure the solar radiation in several channels (typically 4 to 7) with a bandwith from 2 to 10 nm. They require less maintenance than the spectroradiometer and they are able to work in hostile environment as for instance the polar regions. The spectral resolution depends on the width at half maximum (FWHM) of the filters and is generally lower than the spectroradiometer resolution (0.5 nm). Other than the robustness of this instruments, the main advantage of the filter radiometers is the high frequency with which all wavelengths can be measured, making this class of instrument well suited for investigating short term irradiance variation. In this work is presented the results of UV irradiance measurements performed by a very narrow band (FWHM less than 1 nm) filter radiometer at Antarctica Italia Base, Mario Zucchelli Station, Terranova Bay, lat. 74° 41.6084' south and lon. 164° 05.9224' est. All-dielectric Fabry-Perot filters were manufactured in the laboratories of the Optical Coating Group, ENEA, by the ion beam assistance physical vapor deposition technique. Nine filters select nine different wavelengths in the UV spectral range from 296.5 nm to 377 nm with about 1 minute of measurement period, i.e. each wavelength is measured about 1250 times per day. At the moment the radiometer are permanently located near MZS and the data are daily downloaded in ENEA, Rome, by a dedicated satellite channel. During the Antarctica winter the radiometer will be in standby mode, in this season MZS is closed, and it will be start to measure again in the Antarctica spring.

Salvatore, Scaglione; di Sarcina, Ilaria; Flori, Daniele; Menchini, Francesca

2010-05-01

237

An open randomized study to compare narrow band UVB, topical pimecrolimus and topical tacrolimus in the treatment of vitiligo.  

PubMed

Vitiligo is an acquired loss of pigmentation and its treatment remains very difficult up to date. Narrow band ultraviolet B (NB-UVB) and topical immunomodulators are included among the most innovative approaches to vitiligo. We evaluated the efficacy and tolerability of NB-UVB, topical pimecrolimus and tacrolimus in the treatment of vitiligo. Adult patients with chronic and stable vitiligo refractory to conventional therapies were enrolled in an open parallel groups study. The patients were scheduled on the basis of a computer-generated randomization into three groups: 13 patients received NB-UVB phototherapy 3 times a week, 15 patients were treated with pimecrolimus 1% cream b.i.d. and 16 patients applied tacrolimus 0.1% ointment b.i.d. All three treatment regimens were performed for 24 weeks. At baseline and every three weeks for the whole period of therapy the patients were examined through digital photographs and, at the end of the study, based on the percentage of repigmentation, treatment outcome was classified as "absent" (0), "slight" (< 25%), mild (25-49%), "moderate" (50-74%), and "excellent" (> 75%). During the whole period of the study, possible side effects were recorded. The response to treatments varied according to the anatomical location of the lesions. No statistically significant differences in repigmentation for any anatomical site were recorded with the three treatments. The best results were obtained for lesions of the face with pimecrolimus cream and tacrolimus ointment and of the neck with NB-UVB. Statistically significant differences in repigmentation between photo-exposed and covered skin areas were recorded although the patients were asked to avoid direct UV exposition and to apply a very high protection sun screen on vitiligo lesions. All three treatments should be considered as a good option in the treatment of vitiligo. NB-UVB irradiation may represent the optimal choice in generalized vitiligo with topical immunomodulators in localized vitiligo. PMID:19651562

Stinco, Giuseppe; Piccirillo, Fabio; Forcione, Marina; Valent, Francesca; Patrone, Pasquale

2009-01-01

238

HAWC+: A Detector, Polarimetry, and Narrow-Band Imaging Upgrade to SOFIA's Far-Infrared Facility Camera  

NASA Astrophysics Data System (ADS)

HAWC, the High-resolution Airborne Widebandwidth Camera, is the facility far-infrared camera for SOFIA, providing continuum imaging from 50 to 250 microns wavelength. As a result of NASA selection as a SOFIA Second Generation Instruments upgrade investigation, HAWC will be upgraded with enhanced capability for addressing current problems in star formation and interstellar medium physics prior to commissioning in early 2015. We describe the capabilities of the upgraded HAWC+, as well as our initial science program. The mapping speed of HAWC is increased by a factor of 9, accomplished by using NASA/Goddard's Backshort-Under-Grid bolometer detectors in a 64x40 format. Two arrays are used in a dual-beam polarimeter format, and the full complement of 5120 transition-edge detectors is read using NIST SQUID multiplexers and U.B.C. Multi-Channel Electronics. A multi-band polarimeter is added to the HAWC opto-mechanical system, at the cryogenic pupil image, employing rotating quartz half-wave plates. Six new filters are added to HAWC+, bringing the full set to 53, 63, 89, 155, and 216 microns at R = 5 resolution and 52, 63, 88, 158, and 205 microns at R = 300 resolution. The latter filters are fixed-tuned to key fine-structure emission lines from [OIII], [OI], [CII], and [NII]. Polarimetry can be performed in any of the filter bands. The first-light science program with HAWC+ emphasizes polarimetry for the purpose of mapping magnetic fields in Galactic clouds. The strength and character of magnetic fields in molecular clouds before, during, and after the star formation phase are largely unknown, despite pioneering efforts on the KAO and ground-based telescopes. SOFIA and HAWC+ provide significant new capability: sensitivity to extended dust emission (to A_V ~ 1) which is unmatched, ~10 arcsec angular resolution combined with wide-field mapping which allows statistical estimates of magnetic field strength, and wavelength coverage spanning the peak of the far-infrared spectrum of star-forming clouds. Our initial targets include nearby quiescent clouds, active sites of high- and low-mass star formation, remnants of dispersing clouds, and the Galactic center.

Dowell, C. D.; Staguhn, J.; Harper, D. A.; Ames, T. J.; Benford, D. J.; Berthoud, M.; Chapman, N. L.; Chuss, D. T.; Dotson, J. L.; Irwin, K. D.; Jhabvala, C. A.; Kovacs, A.; Looney, L.; Novak, G.; Stacey, G. J.; Vaillancourt, J. E.; HAWC+ Science Collaboration

2013-01-01

239

Prospective clinical and histological study to evaluate the efficacy and safety of a targeted high?intensity narrow band UVB\\/UVA1 therapy for striae alba  

Microsoft Academic Search

Objective: The purpose of this study was to determine the efficacy and safety of a targeted narrow band UVB\\/UVA1 therapy for the treatment of striae alba. Methods: Fourteen individuals with skin types II-VI were enrolled in this 22-week trial that consisted of up to 10 treatments with a combination of UVB\\/UVA1 (MultiClear2, Curelight Ltd, Israel). Participants were treated with a

Neil S. Sadick; Cynthia Magro; Alison Hoenig

2007-01-01

240

Xenon chloride ultraviolet B laser is more effective in treating psoriasis and in inducing T cell apoptosis than narrow-band ultraviolet B  

Microsoft Academic Search

Earlier we reported that a 308-nm xenon chloride (XeCl) UVB laser is highly effective for treating psoriasis. As ultraviolet B light seems to cause T cell apoptosis, in the present study we studied the ability of the XeCl laser to induce T-cell apoptosis in vitro, and then compared the apoptosis-inducing capacities of narrow-band UVB (NB-UVB) light and the XeCl laser.

Zoltán Novák; Béla Bónis; Eszter Baltás; Imre Ocsovszki; Ferenc Ignácz; Attila Dobozy; Lajos Kemény

2002-01-01

241

Fermion condensation around a Coulomb impurity in a Weyl semimetal and in a narrow band gap semiconductor as manifestations of the Landau zero-charge problem  

E-print Network

A Coulomb impurity placed in an undoped Weyl semimetal spontaneously surrounds itself with a cloud of condensed Weyl fermions. We find that the ground-state of this system exhibits an experimentally accessible Landau zero-charge effect: the fermion condensate completely screens out the impurity charge. In a narrow band gap semiconducor this effect manifests itself in the near universality of observable charge of a highly-charged recombination center.

Eugene B. Kolomeisky; Joseph P. Straley

2012-10-05

242

Fermion condensation around a Coulomb impurity in a Weyl semimetal and in a narrow band gap semiconductor as manifestations of the Landau zero-charge problem  

E-print Network

A Coulomb impurity placed in an undoped Weyl semimetal spontaneously surrounds itself with a cloud of condensed Weyl fermions. We find that the ground-state of this system exhibits an experimentally accessible Landau zero-charge effect: the fermion condensate completely screens out the impurity charge. In a narrow band gap semiconducor this effect manifests itself in the near universality of observable charge of a highly-charged recombination center.

Kolomeisky, Eugene B

2012-01-01

243

Detailed features of palisade vessels as a marker of the esophageal mucosa revealed by magnifying endoscopy with narrow band imaging.  

PubMed

The palisade vessels present at the distal end of the esophagus are considered to be a landmark of the esophagogastric junction and indispensable for diagnosis of columnar-lined esophagus on the basis of the Japanese criteria. Here we clarified the features of normal palisade vessels at the esophagogastric junction using magnifying endoscopy. We prospectively studied palisade vessels in 15 patients undergoing upper gastrointestinal endoscopy using a GIF-H260Z instrument (Olympus Medical Systems Co., Tokyo, Japan). All views of the palisade vessels were obtained at the maximum magnification power in the narrow band imaging mode. We divided the area in which palisade vessels were present into three sections: the area from the squamocolumnar junction (SCJ) to about 1 cm orad within the esophagus (Section 1); the area between sections 1 and 3 (Section 2); and the area from the upper limit of the palisade vessels to about 1 cm distal within the esophagus (Section 3). In each section, we analyzed the vessel density, caliber of the palisade vessels, and their branching pattern. The vessel density in Sections 1, 2, and 3 was 9.1 ± 2.1, 8.0 ± 2.6, and 3.3 ± 1.3 per high-power field (mean ± standard deviation [SD]), respectively, and the differences were significant between Sections 1 and 2 (P= 0.0086) and between Sections 2 and 3 (P < 0.0001). The palisade vessel caliber in Sections 1, 2, and 3 was 127.6 ± 52.4 µm, 149.6 ± 58.6 µm, and 199.5 ± 75.1 µm (mean ± SD), respectively, and the differences between Sections 1 and 2, and between Sections 2 and 3, were significant (P < 0.0001). With regard to branching form, the frequency of branching was highest in Section 1, and the 'normal Y' shape was observed more frequently than in Sections 2 and 3. Toward the oral side, the frequency of branching diminished, and the frequency of the 'upside down Y' shape increased. The differences in branching form were significant among the three sections (P < 0.0001). These results indicate that the density of palisade vessels is highest near the SCJ, and that towards their upper limit they gradually become more confluent and show an increase of thickness. Within a limited area near the SCJ, observations of branching form suggest that palisade vessels merge abruptly on the distal side. We have demonstrated that palisade vessels are a useful marker for endoscopic recognition of the lower esophagus. PMID:22098187

Kumagai, Y; Yagi, M; Aida, J; Ishida, H; Suzuki, S; Hashimoto, T; Amanuma, Y; Kusano, M; Mukai, S; Yamazaki, S; Iida, M; Ochiai, T; Matsuura, M; Iwakiri, K; Kawano, T; Hoshihara, Y; Takubo, K

2012-08-01

244

Acoustic emission and velocities associated with the formation of compaction bands in sandstone  

E-print Network

Acoustic emission and velocities associated with the formation of compaction bands in sandstone Je the development of compaction bands in Bleurswiller sandstone, which has a porosity of 25%. Results were obtained of compaction bands in sandstone, J. Geophys. Res., 111, B10203, doi:10.1029/2005JB003854. 1. Introduction [2

Fortin, Jérôme

245

Modeled and observed nitrogen Lyman-Birge-Hopfield band emissions in the earth's dayglow: A comparison  

Microsoft Academic Search

Ultraviolet (UV) spectra obtained from Earth's dayglow contain important information for understanding the thermosphere, and the N2 Lyman-Birge-Hopfield (LBH) bands are possibly the most useful emission. To be useful, a thorough understanding of how the LBH band emission varies with altitude and latitude is essential to present and future use of this emission by space-based remote sensors. Excited by photoelectron

D. Jay Murray

2008-01-01

246

Molecular nitrogen LBH band system far-UV emissions of sprite streamers  

Microsoft Academic Search

The time dependent optical emission model developed by Liu and Pasko (2004) is applied to studies of far-UV emissions of sprite streamers due to N2 Lyman-Birge-Hopfield (LBH) band system. Modeling results indicate that the LBH emissions of sprite streamers at 70 km are generally stronger by up to a factor of 10 than those from the first negative band system

Ningyu Liu; Victor P. Pasko

2005-01-01

247

DOUBLE-PEAKED NARROW EMISSION-LINE GALAXIES FROM THE SLOAN DIGITAL SKY SURVEY. I. SAMPLE AND BASIC PROPERTIES  

SciTech Connect

Recently, much attention has been paid to double-peaked narrow emission-line (NEL) galaxies, some of which are suggested to be related to merging galaxies. We make a systematic search to build the largest sample of these sources from Data Release 7 of the Sloan Digital Sky Survey (SDSS). With reasonable criteria for fluxes, FWHMs of the emission lines, and separations of the peaks, we select 3030 double-peaked NEL galaxies. In light of the existence of broad Balmer lines and the locations of the two components of double-peaked NELs distinguished by the Kauffmann et al. criteria in the Baldwin-Phillips-Terlevich diagram, we find that there are 81 Type I active galactic nuclei (AGNs), 837 double Type II AGNs (2-Type II), 708 galaxies with double star-forming components (2-SF), 400 with mixed star-forming and Type II AGN components (Type II + SF), and 1004 unknown-type objects. As a by-product, a sample of galaxies (12,582) with asymmetric or top-flat profiles of emission lines is established. After visually inspecting the SDSS images of the two samples, we find 54 galaxies with dual cores. The present samples can be used to study the dynamics of merging galaxies, the triggering mechanism of black hole activity, the hierarchical growth of galaxies, and the dynamics of narrow line regions driven by outflows and a rotating disk.

Ge Junqiang; Hu Chen; Wang Jianmin; Zhang Shu [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Beijing 100049 (China); Bai Jinming, E-mail: wangjm@mail.ihep.ac.cn [Yunnan Observatory, Chinese Academy of Sciences, Kunming 650011 (China)

2012-08-01

248

Using Lunar Observations to Assess Terra MODIS Thermal Emissive Bands Calibration  

NASA Technical Reports Server (NTRS)

MODIS collects data in both the reflected solar and thermal emissive regions using 36 spectral bands. The center wavelengths of these bands cover the3.7 to 14.24 micron region. In addition to using its on-board calibrators (OBC), which include a full aperture solar diffuser (SD) and a blackbody (BB), lunar observations have been scheduled on a regular basis to support both Terra and Aqua MODIS on-orbit calibration and characterization. This paper provides an overview of MODIS lunar observations and their applications for the reflective solar bands (RSB) and thermal emissive bands (TEB) with an emphasis on potential calibration improvements of MODIS band 21 at 3.96 microns. This spectral band has detectors set with low gains to enable fire detection. Methodologies are proposed and examined on the use of lunar observations for the band 21 calibration. Also presented in this paper are preliminary results derived from Terra MODIS lunar observations and remaining challenging issues.

Xiong, Xiaoxiong; Chen, Hongda

2010-01-01

249

Using lunar observations to assess Terra MODIS thermal emissive bands calibration  

NASA Astrophysics Data System (ADS)

MODIS collects data in both the reflected solar and thermal emissive regions using 36 spectral bands. The center wavelengths of these bands cover the3.7 to 14.24 micron region. In addition to using its on-board calibrators (OBC), which include a full aperture solar diffuser (SD) and a blackbody (BB), lunar observations have been scheduled on a regular basis to support both Terra and Aqua MODIS on-orbit calibration and characterization. This paper provides an overview of MODIS lunar observations and their applications for the reflective solar bands (RSB) and thermal emissive bands (TEB) with an emphasis on potential calibration improvements of MODIS band 21 at 3.96 microns. This spectral band has detectors set with low gains to enable fire detection. Methodologies are proposed and examined on the use of lunar observations for the band 21 calibration. Also presented in this paper are preliminary results derived from Terra MODIS lunar observations and remaining challenging issues.

Xiong, Xiaoxiong; Chen, Hongda

2010-09-01

250

Relationship between photonic band structure and emission characteristics of a polymer distributed feedback laser  

NASA Astrophysics Data System (ADS)

We present an experimental study of the emission characteristics and photonic band structure of a distributed feedback polymer laser, based on the material poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene]. We use measurements of the photonic band dispersion to explain how the substrate microstructure modifies both spontaneous and stimulated emission. The lasing structure exhibits a one-dimensional photonic band gap around 610 nm, with lasing occurring at one of the two associated band edges. The band edge (frequency) selection mechanism is found to be a difference in the level of output coupling of the modes associated with the two band edges. This is a feature of the second-order distributed feedback mechanism we have employed and is clearly evident in the measured photonic band structure.

Turnbull, G. A.; Andrew, P.; Jory, M. J.; Barnes, W. L.; Samuel, I. D. W.

2001-09-01

251

Shocked Post-starbust Galaxy Survey: Candidate Post-Starbust Galaxies with Narrow Emission Line Ratios Arising from Shocks  

NASA Astrophysics Data System (ADS)

As galaxies age they move from the blue cloud (star forming) to the red sequence (`dead' galaxies) in the color-magnitude diagram of galaxies. Galaxies between the blue cloud and red sequence (i.e., the green valley) are caught in the act of transitioning and they show large Balmer jump and high order Balmer absorption lines in their optical spectra. These galaxies answer to many names (i.e., E+A, K+A, Hdelta-strong, post-starburst), all with similar but slightly different selection criteria. Many studies of transitioning galaxies invoke strong constraints on emission lines in order to guarantee a dominant post-starburst (rather that actively star bursting) stellar population, however these constraints bias the sample against narrow-line emission not arising from star formation, namely active galactic nuclei, low-ionization nuclear emission regions and shocks. Using the Oh-Sarzi-Schawinski-Yi (OSSY) emission and absorption line measurements for SDSS DR7 galaxies we study the intersection between transitioning galaxies and those with shock line ratios. We show that a significant fraction of transitioning galaxies have emission-line ratios indicative of shocks. We postulate that these shocks may be in part responsible for the shepherding of blue star forming galaxies to passive early-types.

Cales, Sabrina; Alatalo, Katherine A.; Appleton, Philip N.; Lisenfeld, Ute; Rich, Jeffrey; Nyland, Kristina; Lacy, Mark; Kewley, Lisa J.

2015-01-01

252

Hearing threshold estimation by auditory steady-state responses with narrow-band chirps and adaptive stimulus patterns: implementation in clinical routine.  

PubMed

Objective hearing threshold estimation by auditory steady-state responses (ASSR) can be accelerated by the use of narrow-band chirps and adaptive stimulus patterns. This modification has been examined in only a few clinical studies. In this study, clinical data is validated and extended, and the applicability of the method in audiological diagnostics routine is examined. In 60 patients (normal hearing and hearing impaired), ASSR and pure tone audiometry (PTA) thresholds were compared. ASSR were evoked by binaural multi-frequent narrow-band chirps with adaptive stimulus patterns. The precision and required testing time for hearing threshold estimation were determined. The average differences between ASSR and PTA thresholds were 18, 12, 17 and 19 dB for normal hearing (PTA ? 20 dB) and 5, 9, 9 and 11 dB for hearing impaired (PTA > 20 dB) at the frequencies of 500, 1,000, 2,000 and 4,000 Hz, respectively, and the differences were significant in all frequencies with the exception of 1 kHz. Correlation coefficients between ASSR and PTA thresholds were 0.36, 0.47, 0.54 and 0.51 for normal hearing and 0.73, 0.74, 0.72 and 0.71 for hearing impaired at 500, 1,000, 2,000 and 4,000 Hz, respectively. Mean ASSR testing time was 33 ± 8 min. In conclusion, auditory steady-state responses with narrow-band-chirps and adaptive stimulus patterns is an efficient method for objective frequency-specific hearing threshold estimation. Precision of threshold estimation is most limited for slighter hearing loss at 500 Hz. The required testing time is acceptable for the application in everyday clinical routine. PMID:24305781

Seidel, David Ulrich; Flemming, Tobias Angelo; Park, Jonas Jae-Hyun; Remmert, Stephan

2015-01-01

253

Unprecedentedly strong and narrow electromagnetic emissions stimulated by high-frequency radio waves in the ionosphere.  

PubMed

Experimental results of secondary electromagnetic radiation, stimulated by high-frequency radio waves irradiating the ionosphere, are reported. We have observed emission peaks, shifted in frequency up to a few tens of Hertz from radio waves transmitted at several megahertz. These emission peaks are by far the strongest spectral features of secondary radiation that have been reported. The emissions are attributed to stimulated Brillouin scattering, long predicted but hitherto never unambiguously identified in high-frequency ionospheric interaction experiments. The experiments were performed at the High-Frequency Active Auroral Research Program (HAARP), Alaska, USA. PMID:19257596

Norin, L; Leyser, T B; Nordblad, E; Thidé, B; McCarrick, M

2009-02-13

254

Unprecedentedly Strong and Narrow Electromagnetic Emissions Stimulated by High-Frequency Radio Waves in the Ionosphere  

SciTech Connect

Experimental results of secondary electromagnetic radiation, stimulated by high-frequency radio waves irradiating the ionosphere, are reported. We have observed emission peaks, shifted in frequency up to a few tens of Hertz from radio waves transmitted at several megahertz. These emission peaks are by far the strongest spectral features of secondary radiation that have been reported. The emissions are attributed to stimulated Brillouin scattering, long predicted but hitherto never unambiguously identified in high-frequency ionospheric interaction experiments. The experiments were performed at the High-Frequency Active Auroral Research Program (HAARP), Alaska, USA.

Norin, L.; Leyser, T. B.; Nordblad, E.; Thide, B.; McCarrick, M. [Swedish Institute of Space Physics, Uppsala (Sweden); BAE Systems Advanced Technologies, Washington, D.C. (United States)

2009-02-13

255

RFID Transponders' RF Emissions in Aircraft Communication and Navigation Radio Bands  

NASA Technical Reports Server (NTRS)

Radiated emission data in aircraft communication and navigation bands are presented for several active radio frequency identification (RFID) tags. The individual tags are different in design, operation and transmitting frequencies. The process for measuring the tags emissions in a reverberation chamber is discussed. Measurement issues dealing with tag interrogation, low level measurement in the presence of strong transmissions, and tags low duty factors are discussed. The results show strong emissions, far exceeding aircraft emission limits and can be of potential interference risks.

Nguyen, Truong X.; Ely, Jay J.; Koppen Sandra V.; Fersch, Mariatheresa S.

2008-01-01

256

Observation of Coherently-Enhanced Tunable Narrow-Band Terahertz Transition Radiation from a Relativistic Sub-Picosecond Electron Bunch Train  

We experimentally demonstrate the production of narrow-band (?f/f ~ =20% at f ~ = 0.5 THz) THz transition radiation with tunable frequency over [0.37, 0.86] THz. The radiation is produced as a train of sub-picosecond relativistic electron bunches transits at the vacuum-aluminum interface of an aluminum converter screen. We also show a possible application of modulated beams to extend the dynamical range of a popular bunch length diagnostic technique based on the spectral analysis of coherent radiation.

Piot, P [Northern Illinois U.; Fermilab; Sun, Y E [Fermilab; Maxwell, T J [Fermilab; Northern Illinois U.; Ruan, J.; Lumpkin, A H [Fermilab; Rihaoui, M M [Northern Illinois U.; Thurman-Keup, R [Fermilab

2011-06-27

257

High-power single mode (>1 W) continuous wave operation of longitudinal photonic band crystal lasers with a narrow vertical beam divergence  

NASA Astrophysics Data System (ADS)

We report on 980nm InGaAs /AlGaAs lasers with a broad waveguide based on a longitudinal photonic band crystal concept. The beam divergence measured as full width at half maximum was as narrow as <5° (vertical). Broad area 100?m multimode devices demonstrated >15W pulsed operation as limited by the current source. Significantly increased modal spot size enabled stable single lateral mode operation in broad ridge 10?m stripes. Maximum continuous wave power in single mode regime of 1.3W for 10?m wide stripe lasers was obtained, being limited by the catastrophic degradation of the unpassivated laser facets.

Novikov, I. I.; Gordeev, N. Yu.; Shernyakov, Yu. M.; Kiselev, Yu. Yu.; Maximov, M. V.; Kop'ev, P. S.; Sharon, A.; Duboc, R.; Arbiv, D. B.; Ben-Ami, U.; Shchukin, V. A.; Ledentsov, N. N.

2008-03-01

258

A 32 x 10 Gb\\/s DWDM metropolitan network demonstration using wavelength-selective photonic cross-connects and narrow-band EDFAs  

Microsoft Academic Search

The feasibility of a 32×10 Gb\\/s dense wavelength-division-multiplexed (DWDM) all-optical short-reach metropolitan network using dynamically reconfigurable three-dimensional microelectromechanical-system-based wavelength-selective photonic cross-connects (WSPXC) is experimentally investigated. Full DWDM amplification at the high-capacity node is performed with low-cost narrow-band erbium-doped fiber amplifiers whose channel gain variation is compensated per span using the inherent channel equalization capability of the WSPXC. With Reed-Solomon forward

Volkan Kaman; Xuezhe Zheng; Shifu Yuan; Jim Klingshirn; Chandrasekhar Pusarla; Roger J. Helkey; Olivier Jerphagnon; John E. Bowers

2005-01-01

259

Detection of a new emission band at 2.8 microns in Comet P/Halley  

NASA Technical Reports Server (NTRS)

A 2.8- to 3.7-micron spectrum of Comet Halley taken in May 1986 is presented. The spectrum shows the 3.36-micron emission feature that most likely arises from carbonaceous material and a previously unknown emission band at 2.8-2.9 microns with no evidence for the 3-micron water-ice band either in reflection or absorption. The 2.8- to 2.9-micron emission feature does not arise from infrared fluorescence from water or OH. Since LTE emission from water is unlikely, the nature of this feature is uncertain.

Tokunaga, A. T.; Nagata, T.; Smith, R. G.

1987-01-01

260

Quasi-random narrow-band model FITS to near-infrared low-temperature laboratory methane spectra and derived exponential-sum absorption coefficients  

NASA Astrophysics Data System (ADS)

Near-infrared 10/cm resolution spectra of methane obtained at various temperatures, pressures, and abundances are fit to a quasi-random narrow-band model. Exponential-sum absorption coefficients for three temperatures (112, 188, and 295 K), and 20 pressures from 0.0001 to 5.6 bars, applicable to the cold environments of the major planets, are then derived from the band model for the 230 wavelengths measured from 1.6 to 2.5 microns. RMS deviations between the laboratory and the exponential-sum synthetic transmissions are reported for the best fitting 50 wavelengths. Deviations relevant to broadband, 1-percent spectral resolution observations are also presented. The validity of exponential-sum coefficients derived from broadband (10/cm) transmission data is demonstrated via direct comparison with line-by-line calculations. The complete atlas of coefficients is available from the Planetary Data System-Planetary Atmospheres Discipline Node.

Baines, K. H.; West, R. A.; Giver, L. P.; Moreno, F.

1993-03-01

261

Quasi-random narrow-band model fits to near-infrared low-temperature laboratory methane spectra and derived exponential-sum absorption coefficients  

NASA Technical Reports Server (NTRS)

Near-infrared 10/cm resolution spectra of methane obtained at various temperatures, pressures, and abundances are fit to a quasi-random narrow-band model. Exponential-sum absorption coefficients for three temperatures (112, 188, and 295 K), and 20 pressures from 0.0001 to 5.6 bars, applicable to the cold environments of the major planets, are then derived from the band model for the 230 wavelengths measured from 1.6 to 2.5 microns. RMS deviations between the laboratory and the exponential-sum synthetic transmissions are reported for the best fitting 50 wavelengths. Deviations relevant to broadband, 1-percent spectral resolution observations are also presented. The validity of exponential-sum coefficients derived from broadband (10/cm) transmission data is demonstrated via direct comparison with line-by-line calculations. The complete atlas of coefficients is available from the Planetary Data System-Planetary Atmospheres Discipline Node.

Baines, Kevin H.; West, Robert A.; Giver, Lawrence P.; Moreno, Fernando

1993-01-01

262

The narrow ultraviolet emission lines of the red dwarf Au Microscopii (dM1.6e)  

NASA Technical Reports Server (NTRS)

It is pointed out that the red dwarfs are the smallest, coolest, faintest, least massive, but most common of normal main-sequence stars. The dMe (H-alpha emission) subclass of the red dwarfs exhibits the largest median soft X-ray to bolometric luminosity ratio of any group of late-type stars. In connection with the present investigation, attention is given to the first high-dispersion spectra of the chromospheric (6000 K) and higher temperature (up to 100,000 K) emissions of a dMe star, AU Microscopii in the far-ultraviolet (1150-2000 A) and middle-ultraviolet (2000-3000 A) bands accessible to the International Ultraviolet Explorer (IUE). AU Mic is one of the most luminous of lower main-sequence stars in C IV and soft X-ray emission.

Ayres, T. R.; Eriksson, K.; Linsky, J. L.; Stencel, R. E.

1983-01-01

263

Narrow-Band Imaging System for the Multi-application Solar Telescope at Udaipur Solar Observatory: Characterization of Lithium Niobate Etalons  

E-print Network

Multi-application Solar Telescope is a 50 cm off-axis Gregorian telescope that has been installed at the lake site of Udaipur Solar Observatory. For quasi-simultaneous photospheric and chromospheric observations, a narrow-band imager has been developed as one of the back-end instruments for this telescope. Narrow-band imaging is achieved using two lithium niobate Fabry-Perot etalons working in tandem as a filter. This filter can be tuned to different wavelengths by changing either voltage, tilt or temperature of the etalons. To characterize the etalons, a Littrow spectrograph was set up, in conjunction with a 15 cm Carl Zeiss Coud\\'e solar telescope. The etalons were calibrated for the solar spectral lines FeI 6173 {\\AA}, and CaII 8542 {\\AA}. In this work, we discuss the characterization of the Fabry-Perot etalons, specifically the temperature and voltage tuning of the system for the spectral lines proposed for observations. We present the details of the calibration set-up and various tuning parameters. We al...

Bayanna, A Raja; Venkatakrishnan, P; Srivastava, N

2014-01-01

264

Narrow band noise as a model of time-dependent accelerations - Study of the stability of a fluid surface in a microgravity environment  

NASA Technical Reports Server (NTRS)

We introduce a stochastic model to analyze in quantitative detail the effect of the high frequency components of the residual accelerations onboard spacecraft (often called g-jitter) on fluid motion. The residual acceleration field is modeled as a narrow band noise characterized by three independent parameters: its intensity G squared, a dominant frequency Omega, and a characteristic spectral width tau exp -1. The white noise limit corresponds to Omega tau goes to O, with G squared tau finite, and the limit of a periodic g-jitter (or deterministic limit) can be recovered for Omega tau goes to infinity, G squared finite. The analysis of the response of a fluid surface subjected to a fluctuating gravitational field leads to the stochastic Mathieu equation driven by both additive and multiplicative noise. We discuss the stability of the solutions of this equation in the two limits of white noise and deterministic forcing, and in the general case of narrow band noise. The results are then applied to typical microgravity conditions.

Casademunt, Jaume; Zhang, Wenbin; Vinals, Jorge; Sekerka, Robert F.

1993-01-01

265

Narrow-Band Imaging System for the Multi-application Solar Telescope at Udaipur Solar Observatory: Characterization of Lithium Niobate Etalons  

NASA Astrophysics Data System (ADS)

Multi-application Solar Telescope is a 50 cm off-axis Gregorian telescope that has been installed at the lake site of Udaipur Solar Observatory. For quasi-simultaneous photospheric and chromospheric observations, a narrow-band imager has been developed as one of the back-end instruments for this telescope. Narrow-band imaging is achieved using two lithium niobate Fabry-Perot etalons working in tandem as a filter. This filter can be tuned to different wavelengths by changing either voltage, tilt or temperature of the etalons. To characterize the etalons, a Littrow spectrograph was set up, in conjunction with a 15 cm Carl Zeiss Coud\\'e solar telescope. The etalons were calibrated for the solar spectral lines FeI 6173 {\\AA}, and CaII 8542 {\\AA}. In this work, we discuss the characterization of the Fabry-Perot etalons, specifically the temperature and voltage tuning of the system for the spectral lines proposed for observations. We present the details of the calibration set-up and various tuning parameters. We also present solar images obtained using the system parameters. We also present solar images obtained using the system.

Raja Bayanna, A.; Mathew, Shibu K.; Venkatakrishnan, P.; Srivastava, N.

2014-10-01

266

Coherent control of spontaneous emission near a photonic band edge: A qubit for quantum computation  

E-print Network

­photon spontaneous emission @5#, classical light localization @6#, a photon­atom bound state @8#, fractionalized demonstrate the coherent control of spontaneous emission for a three­level atom located within a photonic band the three­level atom can be totally suppressed or strongly enhanced depending on the relative phase between

John, Sajeev

267

Coherent control of spontaneous emission near a photonic band edge: A qubit for quantum computation  

E-print Network

-photon spontaneous emission 5 , classical light localization 6 , a photon-atom bound state 8 , fractionalized single-atom demonstrate the coherent control of spontaneous emission for a three-level atom located within a photonic band the three-level atom can be totally suppressed or strongly enhanced depending on the relative phase between

John, Sajeev

268

Unusual stripes in emission and absorption in solar radio bursts: Ropes of fibers in the meter wave band  

NASA Astrophysics Data System (ADS)

Based on data from the spectrographs of IZMIRAN and Tremsdorf station (Astronomical Institute, Potsdam), we analyze the ropes of narrow-band fibers in the spectra of solar radio bursts in the meter wave band by invoking events of satellite data (SOHO/LASCO, EIT, MDI) for the analysis. We consider in detail basic properties of the ropes in four events in comparison with previously known data. The fibers in ropes are more commonly observed with an overlap in time and frequency, but occasionally (more often at the end of the ropes) they can follow with a separation in time. The fiber duration and recurrence period seldom remain stable and, in general, increase from 0.3 0.5 s at the beginning to several seconds at the end of the rope. The relative values of the instantaneous and total fiber frequency bandwidths change only slightly in different events; ? f / f ? 0.003 0.005 and ? f / f ? 0.02 0.03. Most of the ropes exhibit a low-frequency absorption. The fibers in ropes are similar to ordinary intermediate drift bursts (fiber bursts), but they drift in a narrow frequency band and have a more frequent recurrence in some events. The ropes of fibers are usually observed in the time interval when the shock front catches up with the leading edge of a coronal mass ejection. Under the condition of a unified approach to interpreting the ropes of fibers in all events, their basic properties can be explained in terms of the model of fiber bursts. The connection of fibers with the developed zebra pattern is shown within the framework of a unified approach to the formation theory of stripes in emission and absorption in the model on whistlers.

Chernov, G. P.

2008-07-01

269

A deep ROSAT survey 10, X-ray luminous narrow emission line galaxies  

E-print Network

X-ray luminous narrow emision-line galaxies (NELG) have been previously identified and proposed as an important class of extragalactic X-ray sources, with a potentially significant contribution to the total extragalactic X-ray flux at energies below \\sim 10 keV. In order to investigate and clarify this possibility, we have used a sample of NELG found in 5 deep ROSAT fields and similar samples belonging to the Cambridge-Cambridge ROSAT Serendipity Survey and to the {\\it Einstein} Observatory Extended Medium Sensitivity Survey sample. The principal results of this investigation are as follows: a) for a given optical luminosity, the typical X-ray luminosity of NELGs is about one or two orders of magnitude higher than that of normal galaxies; b) the ratio of the surface density of NELGs compared with BLAGN increases from about 0.04 at fx >= 6 x 10^{-13} erg cm^{-2} s^{-1} to about 0.1 at fx >= 10^{-14} erg cm^{-2} s^{-1}, suggesting that the surface density of NL galaxies might be very close to that of BLAGN at f...

Griffiths, R E; Georgantopoulos, I; Boyle, B J; Stewart, G C; Shanks, T; Fruscione, A; Griffiths, Richard E; Della Ceca, Roberto; Georgantopoulos, Ioannis; Boyle, Brian J; Stewart, Gordon C; Shanks, Tom; Fruscione, Antonella

1996-01-01

270

Compact source of narrow-band counterpropagating polarization-entangled photon pairs using a single dual-periodically-poled crystal  

NASA Astrophysics Data System (ADS)

We propose a scheme for the generation of counterpropagating polarization-entangled photon pairs from a dual-periodically-poled crystal. Compared with the usual forward-wave-type source, this source, in the backward-wave way, has a much narrower bandwidth. With a 2-cm-long bulk crystal, the bandwidths of the example sources are estimated to be 3.6 GHz, and the spectral brightnesses are more than 100 pairs/(s GHz mW). Two concurrent quasi-phase-matched spontaneous parametric down-conversion processes in a single crystal enable our source to be compact and stable. This scheme does not rely on any state projection and applies to both degenerate and nondegenerate cases, facilitating applications of the entangled photons.

Gong, Yan-Xiao; Xie, Zhen-Da; Xu, Ping; Yu, Xiao-Qiang; Xue, Peng; Zhu, Shi-Ning

2011-11-01

271

Critical design issues in implementing a YBCO superconductor X -band narrow bandpass filter operating at 77 K  

Microsoft Academic Search

The implementation of a narrowband (0.5%) high-Tc superconducting filter operating at X-band and 77 K is discussed. The authors examine the effects of high-temperature superconductor (HTS) film thickness on the loss performance; kinetic and mutual inductance contributions to the center frequency drift with temperature; and nonlinearities associated with the generation of intermodulation distortion. It is concluded that, in order to

A. Fathy; D. Kalokitis; E. Belohoubek

1991-01-01

272

Amplified spontaneous emission measurement of a line-narrowed, tunable, Ti:Al2O3 amplifier using rubidium absorption  

NASA Technical Reports Server (NTRS)

Amplified spontaneous emission, ASE, generated by a Ti:Al2O3 laser amplifier has been measured as a function of pump energy, and thus gain, using the atomic absorption of rubidium, Rb, gas at 0.780 micron. By tuning the Ti:Al2O3 laser, the Rb cell could selectively absorb the narrow spectral bandwidth laser radiation while transmitting the wide spectral bandwidth ASE. Transmission of laser amplifier pulses through a Rb absorption cell, measured at various temperatures, thus allows the measurement of the weak ASE in the vicinity of the strong laser pulse. A model for the transmission of Rb as a function of temperature and wavelength has been developed. The measured transmissions are in good agreement with the transmission model predictions.

Barnes, James C.; Barnes, Norman P.; Lockard, George E.; Cross, Patricia L.

1989-01-01

273

First results from the FPGA/NIOS Adaptive FIR Filter Using Linear Prediction Implemented in the AERA Radio Stations to Reduce Narrow Band RFI for Radio Detection of Cosmic Rays  

E-print Network

The FPGA/NIOS FIR filter based on linear prediction (LP) to suppress radio frequency interference (RFI) has been installed in several radio stations in the Auger Engineering Radio Array (AERA) experiment. AERA observes coherent radio emission from extensive air showers induced by ultra-high-energy cosmic rays to make a detailed study of the development of the electromagnetic part of air showers. Radio signals provide complementary information to that obtained from Auger surface detectors, which are predominantly sensitive to the particle content of an air shower at the surface. The radio signals from air showers are caused by the coherent emission due to geomagnetic and charge-excess processes. These emissions can be observed in the frequency band between 10 - 100 MHz. However, this frequency range is significantly contaminated by narrow-band RFI and other human-made distortions. A FIR filter implemented in the FPGA logic segment of the front-end electronics of a radio sensor significantly improves the signal-to-noise ratio. In this paper we present first results of the efficiency of the adaptive LP FIR filter, deployed in real AERA station on pampas, with a comparison to the currently used IIR notch filter with constant coefficients. The laboratory tests confirms the stability of the filter. Using constant LP coefficients the suppression efficiency remains the same for hours, which corresponds to more than $\\bf 10^{12}$ clock cycles. We compared in real conditions several variants of the LP FIR filter with various lengths and various coefficients widths (due to fixed-point representations in the FPGA logic) with the aim to minimize the power consumption for the radio station while keeping sufficient accuracy for noise reduction.

Zbigniew Szadkowski; D. G?as; C. Timmermans; T. Wijnen for the Pierre Auger Collaboration

2014-06-03

274

A Narrow-band 8.7 GHz SiGe HBT LNA with a Passive Frequency Selective Feedback  

NASA Astrophysics Data System (ADS)

This paper presents a low noise amplifier (LNA) with differential output using a passive frequency selective feedback. The introduced feedback stabilizes the amplifier at lower frequencies and improves the gain in the desired frequency band. The LNA consists of two stages. Additionally, a buffer at the output is added for measurements. The amplifier was implemented in a 0.35 ?m SiGe technology. For measurements the LNA was bonded to a substrate. A peak gain of 28.1 dB and a minimum noise figure of 2.2 dB at a supply voltage of 3 V were achieved.

Gerlich, Stefan; Weger, Peter

2012-06-01

275

EXTENDED NARROW-LINE EMISSION IN THE BRIGHT SEYFERT 1.5 GALAXY HE 2211-3903  

SciTech Connect

Extended narrow-line regions (ENLRs) and extended emission-line regions have been the focus of integral field spectroscopy aiming at the inner kiloparsecs of nearby Seyfert galaxies as well as the larger environment of high-redshift QSOs. Based on observations with the Wide Field Spectrograph at the 2.3 m telescope of the Australian National University, we present spatially resolved emission-line diagnostics of the bright Seyfert 1.5 galaxy HE 2211-3903 which is drawn from a sample of the brightest Seyfert galaxies at z < 0.06 with luminosities around the classical Seyfert/QSO demarcation. In addition to the previously known spiral arms of HE 2211-3903, the emission-line maps reveal a large-scale ring with a radius of about 6 kpc which is connected to the active galactic nucleus (AGN) through a bar-like structure. The overall gas kinematics indicates a disk rotation pattern. The emission-line ratios show Seyfert-type, H II region-type, and composite classifications, while there is no strong evidence of LINER-type ratios. Shock ionization is likely to be negligible throughout the galaxy. The composite line ratios are explained via a mixing line between AGN and H II region photoionization. Composite line ratios are predominantly found in between the H II regions in the circum-nuclear region, the bar-like structure to the east of the nucleus, and the eastern half of the ring, suggesting AGN photoionization of the low-density interstellar medium in an ENLR on galaxy scales. The line ratios in the nucleus indicate N enrichment, which is discussed in terms of chemical enrichment by Wolf-Rayet and asymptotic giant branch stars during past and ongoing nuclear starburst activity.

Scharwaechter, J.; Dopita, M. A. [Research School of Astronomy and Astrophysics, The Australian National University, Mount Stromlo Observatory, Cotter Road, Weston Creek 2611 (Australia); Zuther, J.; Fischer, S.; Eckart, A. [I. Physikalisches Institut, Universitaet zu Koeln, Zuelpicher Strasse 77, 50937 Koeln (Germany); Komossa, S., E-mail: julia@mso.anu.edu [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, 85741 Garching (Germany)

2011-08-15

276

Improved efficiency of ternary the blend polymer solar cells by doping a narrow band gap polymer material  

NASA Astrophysics Data System (ADS)

A series of P3HT:PC71BM polymer solar cells (PSCs) with different PIDTDTQx doping concentrations were fabricated to investigate the effect of the PIDTDTQx as a complementary electron donor on the performance of PSCs. The power conversion efficiency (PCE) of the optimized ternary blend PSCs (with 2 wt% PIDTDTQx) reached 3.87%, which is 28% higher than that of the PSCs based on P3HT:PC71BM (control cells). The short-circuit current density ( J sc) was increased to 10.20 mA/cm2 compared with the control cells. The PCE improvement could be attributed to more photon harvest and charge carrier transport by appropriate doping PIDTDTQx. The energy transfer from P3HT to PIDTDTQx was demonstrated from the 650 nm emission intensity decrease and the red-shifted emission peaks from 725 nm to 737 nm along with the increase of PIDTDTQx doping concentrations.

Zhu, XiXiang; An, QiaoShi; Huang, Hui; Jiao, ChaoQun; Zhang, FuJun

2015-03-01

277

A deep ROSAT Survey X: X-ray Luminous Narrow Emission Line Galaxies  

E-print Network

X-ray luminous narrow emision-line galaxies (NELG) have been previously identified and proposed as an important class of extragalactic X-ray sources, with a potentially significant contribution to the total extragalactic X-ray flux at energies below $\\sim$ 10 keV. In order to investigate and clarify this possibility, we have used a sample of NELG found in 5 deep ROSAT fields and similar samples belonging to the Cambridge-Cambridge ROSAT Serendipity Survey and to the {\\it Einstein} Observatory Extended Medium Sensitivity Survey sample. The principal results of this investigation are as follows: a) for a given optical luminosity, the typical X-ray luminosity of NELGs is about one or two orders of magnitude higher than that of normal galaxies; b) the ratio of the surface density of NELGs compared with BLAGN increases from about 0.04 at fx >= 6 x 10^{-13} erg cm^{-2} s^{-1} to about 0.1 at fx >= 10^{-14} erg cm^{-2} s^{-1}, suggesting that the surface density of NL galaxies might be very close to that of BLAGN at fx ~ 10^{-15} erg cm^{-2} s^{-1}; c) we find that these objects are described by a cosmological evolution rate similar to that of soft X-ray selected BLAGN; d) the de-evolved (z=0) XLF of NELGs in the luminosity range 10^{41} - 5 x 10^{43} erg s^{-1} is steeper than the BLAGN (z=0) XLF in the same luminosity interval. Their spatial density is significantly lower than the spatial density of X-ray selected BLAGN at Lx(z=0) ~ 5 x 10^{43} erg s^{-1}, but this difference decreases at lower luminosities such that at Lx(z=0) < 10^{42} erg s^{-1} the spatial density of NELGs is very close to that of BLAGN. The implications of these results for the contribution of this class of objects to the cosmic X-ray background are discussed.

Richard E. Griffiths; Roberto Della Ceca; Ioannis Georgantopoulos; Brian J. Boyle; Gordon C. Stewart; Tom Shanks; Antonella Fruscione

1996-03-19

278

Masking of low-frequency signals by high-frequency, high-level narrow bands of noisea  

PubMed Central

Low-frequency masking by intense high-frequency noise bands, referred to as remote masking (RM), was the first evidence to challenge energy-detection models of signal detection. Its underlying mechanisms remain unknown. RM was measured in five normal-hearing young-adults at 250, 350, 500, and 700 Hz using equal-power, spectrally matched random-phase noise (RPN) and low-noise noise (LNN) narrowband maskers. RM was also measured using equal-power, two-tone complex (TC2) and eight-tone complex (TC8). Maskers were centered at 3000 Hz with one or two equivalent rectangular bandwidths (ERBs). Masker levels varied from 80 to 95 dB sound pressure level in 5 dB steps. LNN produced negligible masking for all conditions. An increase in bandwidth in RPN yielded greater masking over a wider frequency region. Masking for TC2 was limited to 350 and 700 Hz for one ERB but shifted to only 700 Hz for two ERBs. A spread of masking to 500 and 700 Hz was observed for TC8 when the bandwidth was increased from one to two ERBs. Results suggest that high-frequency noise bands at high levels could generate significant low-frequency masking. It is possible that listeners experience significant RM due to the amplification of various competing noises that might have significant implications for speech perception in noise. PMID:21361445

Patra, Harisadhan; Roup, Christina M.; Feth, Lawrence L.

2011-01-01

279

Broadband femtosecond OPCPA system driven by the single-shot narrow-band iodine photodissociation laser SOFIA  

NASA Astrophysics Data System (ADS)

A two-stage optical parametric amplifier driven by a frequency-tripled beam from the high-energy iodine laser system SOFIA was built. This single-shot Optical Parametric Chirped Pulse-Amplification facility (OPCPA) and the system synchronizing the pump and signal pulses are described in detail. The chirped seed pulse of a Ti:sapphire oscillator running at the central wavelength of 800 nm is amplified in the two-stage (LBO and KDP) optical parametric amplifier over 108 times. The amplified spectral bandwidth of 68 nm corresponds to the pulse duration of 14 fs when a transform-limited pulse is assumed. This implies a compressed pulse of TW power. Systematic gain measurements reveal a good match with the theoretical predictions. Signal and idler beam fluence profiles are presented. The suitability of the iodine photo-dissociation laser as a pump source for the OPCPA technique is thus proved for the first time experimentally. A distinctive feature of the iodine laser is its very narrow gain bandwidth (<0.1 cm-1) and, therefore, the conventional chirped-pulse amplification technique does not lead to pulse durations at the femtosecond level.

Novák, O.; Tur?i?ová, H.; Smrž, M.; Huynh, J.; Pfeifer, M.; Straka, P.

2012-09-01

280

An optimization of the FPGA/NIOS adaptive FIR filter using linear prediction to reduce narrow band RFI for the next generation ground-based ultra-high energy cosmic-ray experiment  

NASA Astrophysics Data System (ADS)

The electromagnetic part of an extensive air shower developing in the atmosphere provides significant information complementary to that obtained by water Cherenkov detectors which are predominantly sensitive to the muonic content of an air shower at ground. The emissions can be observed in the frequency band between 10 and 100 MHz. However, this frequency range is significantly contaminated by narrow-band RFI and other human-made distortions. The Auger Engineering Radio Array currently suppresses the RFI by multiple time-to-frequency domain conversions using an FFT procedure as well as by a set of manually chosen IIR notch filters in the time-domain. An alternative approach developed in this paper is an adaptive FIR filter based on linear prediction (LP). The coefficients for the linear predictor are dynamically refreshed and calculated in the virtual NIOS processor. The radio detector is an autonomous system installed on the Argentinean pampas and supplied from a solar panel. Powerful calculation capacity inside the FPGA is a factor. Power consumption versus the degree of effectiveness of the calculation inside the FPGA is a figure of merit to be minimized. Results show that the RFI contamination can be significantly suppressed by the LP FIR filter for 64 or less stages.

Szadkowski, Zbigniew; Fraenkel, E. D.; Glas, Dariusz; Legumina, Remigiusz

2013-12-01

281

Recent Emission Channeling Studies in Wide Band Gap Semiconductors  

NASA Astrophysics Data System (ADS)

We present results of recent emission channeling experiments on the lattice location of implanted Fe and rare earths in wurtzite GaN and ZnO. In both cases the majority of implanted atoms are found on substitutional cation sites. The root mean square displacements from the ideal substitutional Ga and Zn sites are given and the stability of the Fe and rare earth lattice location against thermal annealing is discussed.

Wahl, U.; Correia, J. G.; Rita, E.; Alves, E.; Soares, J. C.; de Vries, B.; Matias, V.; Vantomme, A.

2004-12-01

282

Compact high-quality CdSe/CdS core/shell nanocrystals with narrow emission linewidths and suppressed blinking  

PubMed Central

High particle uniformity, high photoluminescence quantum yields, narrow and symmetric emission spectral lineshapes and minimal single dot emission intermittency (known as blinking) have been recognized as universal requirements for the successful use of colloidal quantum dots (QDs) in nearly all optical applications. However, synthesizing samples that simultaneously meet all these four criteria has proven challenging. Here, we report the synthesis of such high-quality CdSe/CdS core/shell QDs in an optimized process which maintains a slow growth rate of the shell through the use of octanethiol and cadmium oleate as precursors. In contrast with previous observations, single-QD blinking is significantly suppressed with only a relatively thin shell. In addition, we demonstrate the elimination of the ensemble luminescence photodarkening that is an intrinsic consequence of QD blinking statistical aging. Furthermore, the small size and high photoluminescence quantum yields of these novel QDs render them superior in vivo imaging agents compared to conventional QDs. We anticipate that this new generation of QDs will also result in significant improvement in the performance of QDs in other applications such as solid-state lighting and illumination. PMID:23377294

Chen, Ou; Zhao, Jing; Chauhan, Vikash P.; Cui, Jian; Wong, Cliff; Harris, Daniel K.; Wei, He; Han, Hee-Sun; Fukumura, Dai; Jain, Rakesh K.; Bawendi, Moungi G.

2013-01-01

283

33 W quasi-continuous-wave narrow-band sodium D2a laser by sum-frequency generation in LBO  

NASA Astrophysics Data System (ADS)

We demonstrate an all-solid quasi-continuous-wave (QCW) narrow-band source tunable to sodium D2a line at 589.159 nm. The source is based on sum-frequency mixing between lasers at 1064 nm and 1319 nm in a LBO crystal. The 1064 nm and 1319 nm lasers are produced from two diode side-pumped Nd:YAG master oscillator power amplifier (MOPA) laser systems, respectively. A 33 W output of 589 nm laser is obtained with beam quality factor M2 = 1.25, frequency stability better than ±0.2 GHz and linewidth less than 0.44 GHz. A prototype 589 nm laser system is assembled, and a sodium laser guided star has been successfully observed in the field test.

Wang, Peng-Yuan; Xie, Shi-Yong; Bo, Yong; Wang, Bao-Shan; Zuo, Jun-Wei; Wang, Zhi-Chao; Shen, Yu; Zhang, Feng-Feng; Wei, Kai; Jin, Kai; Xu, Yi-Ting; Xu, Jia-Lin; Peng, Qin-Jun; Zhang, Jing-Yuan; Lei, Wen-Qiang; Cui, Da-Fu; Zhang, Yu-Dong; Xu, Zu-Yan

2014-09-01

284

Side-chain effects on the conductivity, morphology, and thermoelectric properties of self-doped narrow-band-gap conjugated polyelectrolytes.  

PubMed

This contribution reports a series of anionic narrow-band-gap self-doped conjugated polyelectrolytes (CPEs) with ?-conjugated cyclopenta-[2,1-b;3,4-b']-dithiophene-alt-4,7-(2,1,3-benzothiadiazole) backbones, but with different counterions (Na(+), K(+), vs tetrabutylammonium) and lengths of alkyl chains (C4 vs C3). These materials were doped to provide air-stable, water-soluble conductive materials. Solid-state electrical conductivity, thermopower, and thermal conductivity were measured and compared. CPEs with smaller counterions and shorter side chains exhibit higher doping levels and form more ordered films. The smallest countercation (Na(+)) provides thin films with higher electrical conductivity, but a comparable thermopower, compared to those with larger counterions, thereby leading to a higher power factor. Chemical modifications of the pendant side chains do not influence out of plane thermal conductivity. These studies introduce a novel approach to understand thermoelectric performance by structural modifications. PMID:25179403

Mai, Cheng-Kang; Schlitz, Ruth A; Su, Gregory M; Spitzer, Daniel; Wang, Xiaojia; Fronk, Stephanie L; Cahill, David G; Chabinyc, Michael L; Bazan, Guillermo C

2014-10-01

285

Narrow band fiber-optic phase-shifted Fabry-Perot Bragg grating filters for atmospheric water vapor lidar measurements.  

PubMed

A unique ultranarrowband fiber-optic phase-shifted Fabry-Perot Bragg grating filter for atmospheric water vapor lidar measurements was designed, fabricated, and successfully tested. Customized optical fiber Bragg gratings were fabricated so that two transmission filter peaks occurred: one (89% transmission, 8 pm FWHM) near the 946-nm water vapor absorption line and the other peak (80% transmission, 4 pm FWHM) at a region of no absorption. Both transmission peaks were within a 2.66-nm stop band. Demonstration of tension tuning to the 946.0003-nm water vapor line was achieved, and the performance characterization of custom-made optical fiber Bragg grating filters are presented. These measurements are successfully compared to theoretical calculations using a piecewise-matrix form of the coupled-mode equations. PMID:16353809

Vann, Lelia B; DeYoung, Russell J; Mihailov, Stephen J; Lu, Ping; Grobnic, Dan; Walker, Robert

2005-12-01

286

Narrow-band Filter Observations of the Red-Line Corona at the 29 March 2006 Eclipse  

NASA Astrophysics Data System (ADS)

We report on observations of the corona above active region NOAA 10866, which was on the solar east limb at S 06 on 29 March 2006. Filtergrams were obtained at six 0.22 Å steps across the profile of the Fe X line at 6374.5 Å during the total solar eclipse, starting at about 1052 UT. The telescope was a 35-cm Schmidt-Cassegrain Meade RCX400 with the solar image relayed to a 512 x 512-pixel Andor Ixon DV887 CCD camera via telecentric optics and two narrow-bandpass filters: (1) a 2 Å thin-film Andover Corp. blocker and (2) a 0.16 Å tunable Fabry-Perot etalon, made by the CSIRO Australian Centre for Precision Optics. The F-P etalon is a Y-cut lithium niobate wafer of 0.200-mm thickness coated with reflective and conductive thin-film layers. Application of a voltage to the etalon produces a passband shift of 0.0011 Å/volt. Calibration at the eclipse site in Kastellorizo, Greece, was maintained by reference to a WSTech thermo-electrically stabilized diode laser tuned to 6375.16 Å. The profile and Doppler shifts of the Fe X line will be discussed.The expedition was supported by NSF (ATM-0552116), the Committee for Research and Exploration of the National Geographic Society, NASA's Planetary Astronomy Division for the CCD cameras (NNG04GE48G), Sigma Xi, and the Rob Spring Fund and the Ryan Patrick Gaishin Fund at Williams College.

Rust, David M.; Noble, M. W.; Pasachoff, J. M.; Babcock, B. A.; Bruck, M. A.; Wittenmyer, R. A.

2006-06-01

287

Yb5Ga2Sb6: a mixed valent and narrow-band gap material in the RE5M2X6 family.  

PubMed

A new compound Yb5Ga2Sb6 was synthesized by the metal flux technique as well as high frequency induction heating. Yb5Ga2Sb6 crystallizes in the orthorhombic space group Pbam (no. 55), in the Ba5Al2Bi6 structure type, with a unit cell of a = 7.2769(2) Å, b = 22.9102(5) Å, c = 4.3984(14) Å, and Z = 2. Yb5Ga2Sb6 has an anisotropic structure with infinite anionic double chains (Ga2Sb6)(10-) cross-linked by Yb(2+) and Yb(3+) ions. Each single chain is made of corner-sharing GaSb4 tetrahedra. Two such chains are bridged by Sb2 groups to form double chains of 1/? [Ga2Sb6(10-)]. The compound satisfies the classical Zintl-Klemm concept and is a narrow band gap semiconductor with an energy gap of around 0.36 eV calculated from the electrical resistivity data corroborating with the experimental absorption studies in the IR region (0.3 eV). Magnetic measurements suggest Yb atoms in Yb5Ga2Sb6 exist in the mixed valent state. Temperature dependent magnetic susceptibility data follows the Curie-Weiss behavior above 100 K and no magnetic ordering was observed down to 2 K. Experiments are accompanied by all electron full-potential linear augmented plane wave (FP-LAPW) calculations based on density functional theory to calculate the electronic structure and density of states. The calculated band structure shows a weak overlap of valence band and conduction band resulting in a pseudo gap in the density of states revealing semimetallic character. PMID:24224906

Subbarao, Udumula; Sarkar, Sumanta; Gudelli, Vijay Kumar; Kanchana, V; Vaitheeswaran, G; Peter, Sebastian C

2013-12-01

288

Band-Structure Based model for photoelectron emission from metal surfaces  

NASA Astrophysics Data System (ADS)

Photoelectron emission spectra induced by grazing incidence of intense and ultrashort laser pulses on a metal surface are studied within a distorted-wave formalism. The proposed aproximation, named Band-Structure Based-Volkov (BSB-V) approach, includes a precise description of the surface potential, incorporating information of the band structure of the solid. Results are compared with the numerical solution of the time-dependent Schrodinger equation and with values derived from simpler theoretical models.

Rios, C. A.; Gravielle, M. S.; Mitnik, D. M.; Silkin, V. M.

2012-11-01

289

Bulk band gaps in divalent hexaborides: A soft x-ray emission study  

SciTech Connect

Boron K-edge soft x-ray emission and absorption are used to address the fundamental question of whether divalent hexaborides are intrinsic semimetals or defect-doped bandgap insulators. These bulk sensitive measurements, complementary and consistent with surface-sensitive angle-resolved photoemission experiments, confirm the existence of a bulk band gap and the location of the chemical potential at the bottom of the conduction band.

Denlinger, Jonathan D.; Gweon, Gey-Hong; Allen, James W.; Bianchi, Andrea D.; Fisk, Zachary

2001-10-03

290

Ocean Surface Emissivity at L-band (1.4 GHz): The Dependence on Salinity and Roughness  

NASA Technical Reports Server (NTRS)

A characterization of the emissivity of sea water at L-band is important for the remote sensing of sea surface salinity. Measurements of salinity are currently being made in the radio astronomy band at 1.413 GHz by ESA's Soil Moisture and Ocean Salinity (SMOS) mission and NASA's Aquarius instrument aboard the Aquarius/SAC-D observatory. The goal of both missions is accuracy on the order of 0.1 psu. This requires accurate knowledge of the dielectric constant of sea water as a function of salinity and temperature and also the effect of waves (roughness). The former determines the emissivity of an ideal (i.e. flat) surface and the later is the major source of error from predictions based on a flat surface. These two aspects of the problem of characterizing the emissivity are being addressed in the context of the Aquarius mission. First, laboratory measurements are being made of the dielectric constant of sea water. This is being done at the George Washington University using a resonant cavity. In this technique, sea water of known salinity and temperature is fed into the cavity along its axis through a narrow tube. The sea water changes the resonant frequency and Q of the cavity which, if the sample is small enough, can be related to the dielectric constant of the sample. An extensive set of measurements have been conducted at 1.413 GHz to develop a model for the real and imaginary part of the dielectric constant as a function of salinity and temperature. The results are compared to the predictions of models based on parameterization of the Debye resonance of the water molecule. The models and measurements are close; however, the differences are significant for remote sensing of salinity. This is especially true at low temperatures where the sensitivity to salinity is lowest.

LeVine, D. M.; Lang, R.; Wentz, F.; Messiner, T.

2012-01-01

291

Giant enhancement of band edge emission based on ZnO/TiO(2) nanocomposites.  

PubMed

Enhancement of band edge emission of ZnO nanorods up to a factor of 120 times has been observed in the composite consisting of ZnO nanorods and TiO(2) nanoparticles, while the defect emission of ZnO nanorods is quenched to noise level. Through a detailed investigation, it is found that the large enhancement mainly arises from fluorescence resonance energy transfer between the band edge transition of ZnO nanorods and TiO(2) nanoparticles. Our finding opens up new possibilities for the creation of highly efficient solid state emitters. PMID:19550653

Lin, H Y; Chou, Y Y; Cheng, C L; Chen, Y F

2007-10-17

292

The Luminosity Function and Star Formation Rate Between Redshifts of 0.07 and 1.47 for Narrow-band Emitters in the Subaru Deep Field  

NASA Astrophysics Data System (ADS)

Subaru Deep Field line-emitting galaxies in four narrow-band filters at low and intermediate redshifts are presented. Broad-band colors, follow-up optical spectroscopy, and multiple narrow-band filters are used to distinguish H?, [OII], and [OIII] emitters between redshifts of 0.07 and 1.47 to construct their averaged rest-frame optical-to-UV SED and luminosity functions. These luminosity functions are derived down to faint magnitudes, which allows for a more accurate determination of the faint end slope. With a large (N 200-900) sample for each redshift interval, a Schechter profile is fitted to each luminosity function. Prior to dust extinction corrections, the [OIII] and [OII] luminosity functions reported in this paper agree reasonably well with those of Hippelein et al (2003). The z=0.066-0.092 H? LF agrees with those of Jones & Bland-Hawthorn (2001), but for z=0.24 and 0.40, their number density is higher by a factor of two or more. The z=0.08 H? LF, which reaches two orders of magnitude fainter than Gallego et al. (1995), is steeper by 25%. This indicates that there are more low luminosity star-forming galaxies for z<0.1 than predicted. The faint end slope ? and ?* show a strong evolution with redshift while L* show little evolution. The evolution in ? indicates that low-luminosity galaxies have a stronger evolution compared to brighter ones. Integrated star formation rate densities are derived via H? for 0.07

Ly, Chun; Malkan, M.; Kashikawa, N.; Shimasaku, K.; Doi, M.; Nagao, T.; Iye, M.; Kodama, T.; Morokuma, T.; Motohara, K.

2006-06-01

293

The emission spectrum of helium hydride. II - Bands near 5500 and 6400 A  

Microsoft Academic Search

The emission bands of helium hydride near 5500 and 6400 A? were analyzed for 4HeH, 3HeD, and 4HeD. They are assigned to the emission of the coupled states D 2?+, (3d, L=2) and (for the deuterides) C 2?+, v=3 to the A 2?+ (5500 A?) and B 2&Pgr; (6400 A?) states. The 3d, L=2 state is treated as pure Hund’s

Wolfgang Ketterle

1990-01-01

294

Updated modeling of the N2 LBH band emissions in the Earth's thermosphere  

Microsoft Academic Search

Much of the information derived from remote sensing of the thermosphere depends on our understanding of the N2 Lyman-Birge-Hopfield (LBH) band emissions. This emission is essential to techniques used to derive atomic oxygen to molecular nitrogen (O\\/N2) density ratios, to molecular nitrogen densities and to remotely sensing the temperature of the lower thermosphere. There has been uncertainty and debate about

R. Eastes; A. Kulshreshth

2009-01-01

295

Detecting long-duration narrow-band gravitational wave transients associated with soft gamma repeater quasiperiodic oscillations  

NASA Astrophysics Data System (ADS)

We have performed an in-depth concept study of a gravitational wave data analysis method which targets repeated long quasimonochromatic transients (triggers) from cosmic sources. The algorithm concept can be applied to multitrigger data sets in which the detector-source orientation and the statistical properties of the data stream change with time, and does not require the assumption that the data is Gaussian. Reconstructing or limiting the energetics of potential gravitational wave emissions associated with quasiperiodic oscillations observed in the x-ray lightcurve tails of soft gamma repeater flares might be an interesting endeavor of the future. Therefore we chose this in a simplified form to illustrate the flow, capabilities, and performance of the method. We investigate performance aspects of a multitrigger based data analysis approach by using O(100s) long stretches of mock data in coincidence with the times of observed quasiperiodic oscillations, and by using the known sky location of the source. We analytically derive the probability density function of the background distribution and compare to the results obtained by applying the concept to simulated Gaussian noise, as well as off-source playground data collected by the 4-km Hanford detector during LIGO’s fifth science run (S5). We show that the transient glitch rejection and adaptive differential energy comparison methods we apply succeed in rejecting outliers in the fifth science run background data. Finally, we discuss how to extend the method to a network containing multiple detectors, and as an example, tune the method to maximize sensitivity to soft gamma repeater 1806-20 flare times.

Murphy, David; Tse, Maggie; Raffai, Peter; Bartos, Imre; Khan, Rubab; Márka, Zsuzsa; Matone, Luca; Redwine, Keith; Márka, Szabolcs

2013-05-01

296

Reinvestigation of the Emission ? Band System (A2?+-X2?) of the NO Molecule  

NASA Astrophysics Data System (ADS)

In the emission spectrum of the nitric oxide molecule 13 bands of the ? system (A2?+-X2?) were recorded and analyzed. The following bands of this system comprising over 3950 lines were photographed under high resolution by using conventional spectroscopy and Th standard lines: 0-0 through 0-6 and 1-4, 1-5, 2-0, 2-6, 2-7, and 3-4. The analysis of the individual bands and the merged analysis of the entire band system made it possible to unify, extend, and improve the information about the ? system and the energy structure of its participating statesA2?+andX2?. RKR turning points of theAandXstates and Franck-Condon factors andrcentroids for theA-Xsystem were also determined using the precise molecular parameters obtained in the present work.

Danielak, J.; Domin, U.; Ke, R.; Rytel, M.; Zachwieja, M.

1997-02-01

297

High resolution emission Fourier transform infrared spectra of the 4p-5s and 5p-6s bands of ArH  

NASA Astrophysics Data System (ADS)

In the 2500-8500cm-1 region several strong emission bands of ArH40 were observed by Fourier transform spectroscopy through a dc glow discharge in a mixture of argon and hydrogen. Rotational-electronic transitions of the two previously unstudied 4p-5s and 5p-6s,v=0-0, bands of ArH40 were measured and assigned in the 6060 and 3770cm-1 regions, respectively. A simultaneous fit of the emission transitions of the 4p-5s and 5p-6s bands and an extended set of transitions of the 6s-4p band observed by Dabrowski, Tokaryk, and Watson [J. Mol. Spectrosc. 189, 95 (1998)] and remeasured in the present work yielded consistent values of the spectroscopic parameters of the electronic states under investigation. In the branch of the 4p-5s band with transitions of type Qf3eQ we observed a narrowing in the linewidths with increasing rotational quantum number N. The rotational dependence of the linewidth is caused by predissociation of the 5s state by the repulsive ground 4s state through homogeneous coupling and changes in overlap integrals of the vibrational wave functions with the rotational level. Analysis was based on the Fermi's golden rule approximation model. In the 4p-5s band region a vibrational sequence ofv'-v?=1-1, 2-2, and 3-3 were recorded and a number of transitions belonging to the strongest Qf3eQ form branch of the 1-1 band were analyzed.

Baskakov, O. I.; Civiš, S.; Kawaguchi, K.

2005-03-01

298

Polycyclic aromatic hydrocarbons and the unidentified infrared emission bands - Auto exhaust along the Milky Way  

NASA Technical Reports Server (NTRS)

The unidentified infrared emission features (UIR bands) are attributed to a collection of partially hydrogenated, positively charged polycyclic aromatic hydrocarbons (PAHs). This assignment is based on a spectroscopic analysis of the UIR bands. Comparison of the observed interstellar 6.2 and 7.7-micron bands with the laboratory measured Raman spectrum of a collection of carbon-based particulates (auto exhaust) shows a very good agreement, supporting this identification. The infrared emission is due to relaxation from highly vibrationally and electronically excited states. The excitation is probably caused by UV photon absorption. The infrared fluorescence of one particular, highly vibrationally excited PAH (chrysene) is modeled. In this analysis the species is treated as a molecule rather than bulk material and the non-thermodynamic equilibrium nature of the emission is fully taken into account. From a comparison of the observed ratio of the 3.3 to 11.3-micron UIR bands with the model calculations, the average number of carbon atoms per molecule is estimated to be about 20. The abundance of interstellar PAHs is calculated to be about 2 x 10 to the -7th with respect to hydrogen.

Allamandola, L. J.; Tielens, A. G. G. M.; Barker, J. R.

1985-01-01

299

Modeled and observed nitrogen Lyman-Birge-Hopfield band emissions in the earth's dayglow: A comparison  

NASA Astrophysics Data System (ADS)

Ultraviolet (UV) spectra obtained from Earth's dayglow contain important information for understanding the thermosphere, and the N2 Lyman-Birge-Hopfield (LBH) bands are possibly the most useful emission. To be useful, a thorough understanding of how the LBH band emission varies with altitude and latitude is essential to present and future use of this emission by space-based remote sensors. Excited by photoelectron impact on N2 leading to transitions from the a 1pi g state to the ground state, the LBH emissions radiate between 1270 and 2400 A. In addition to being populated by electron impact excitation, the a 1pig state is populated by radiative and collisional cascading from adjacent singlet states a' 1Sigma -u, and w 1Deltau (Eastes, 2000). Ultimately, the intensity is most dependent on low energy electron flux (Ajello and Shemansky, 1985; Meier, 1991) because that is where the electron impact scattering cross sections of the singlet states are the largest. This dissertation presents modeled LBH profiles produced using the Intrasystem Cascade Excitation (ICE) model (Eastes, 2000) with photoelectron fluxes calculated using the Continuous Slowing Down (CSD) model (Jasperse, 1976). Both of these models implement the Mass Spectrometer and Incoherent Scatter (MSIS) to model an atmosphere. Modeled emissions are compared against observations by the High resolution Ionospheric and Thermospheric Spectrograph (HITS) on the Advanced Research and Global Observation Satellite (ARGOS). This dissertation will investigate the LBH emissions in detail and ultimately use them for remote sensing of thermospheric temperatures.

Murray, D. Jay

300

The effect of Neel relaxation on the properties of the third harmonic signal of magnetic nanoparticles for use in narrow-band magnetic nanoparticle imaging  

NASA Astrophysics Data System (ADS)

We study the third harmonic signal of magnetic nanoparticles (MNPs) for use in narrow-band magnetic nanoparticle imaging. We measured the properties of the third harmonic signal, such as frequency and magnetic field dependencies, when the behavior of MNPs was dominated by Neel relaxation. It was shown that the third harmonic signal had both real and imaginary parts, although only the real part is expected from the conventional Langevin function. The real and imaginary parts exhibited different dependences on the frequency and magnetic field. The dynamic behavior of MNPs was analyzed by taking into account the Neel relaxation of MNPs. It was shown that the imaginary part was generated due to Neel relaxation. We obtain an analytical expression for the third harmonic signal, in which distributions of magnetic moment and anisotropic energy of MNPs in the sample were also considered. We show that the analytical results quantitatively explain the experimental results. Our results indicate that the properties of the third harmonic signal of immobilized MNPs are significantly affected by Neel relaxation.

Enpuku, Keiji; Bai, Shi; Hirokawa, Aiki; Tanabe, Kazuhiro; Sasayama, Teruyoshi; Yoshida, Takashi

2014-10-01

301

A space-borne fiber-optic interrogator module based on narrow-band tunable laser diode for temperature monitoring in telecommunication satellites  

NASA Astrophysics Data System (ADS)

In this paper measurement results of the fiber-optic interrogator module for telecommunication satellite applications are presented. The sensor interrogator features from fiber Bragg grating (FBG) based sensing. Benefits are intrinsic sensor distribution capability and the possibility to embed optical fibers in composite structures like tanks and satellite panels. The fiber-optic interrogator module is based on a narrow-band monolithic laser diode where the output wavelength is spectrally tuned by electric control signals. By evaluating the intensities of the sensor response, the peak of the FBG can be monitored. The correct evaluation of the sensor response is a challenging task, therefore different computational methods are presented, namely centroid, finite impulse response filter and curve fitting algorithms. The algorithms shall met the performance requirements in terms of measurement accuracy, robustness against laser degradation and measurement rate. Furthermore the algorithms shall be implemented in an FPGA, which means a detailed point of view to fixed-point arithmetic and necessary amount of hardware resources at constant performance. Measurement results based on the different FBG evaluation algorithms are presented and traded regarding accuracy robustness and their possible implementation in an FPGA.

Putzer, P.; Kuhenuri, N.; Koch, A. W.; Schweyer, S.; Hurni, A.; Plattner, M.

2013-04-01

302

Feeding at a high pitch: source parameters of narrow band, high-frequency clicks from echolocating off-shore hourglass dolphins and coastal Hector's dolphins.  

PubMed

Toothed whales depend on echolocation for orientation and prey localization, and source parameters of echolocation clicks from free-ranging animals therefore convey valuable information about the acoustic physiology and behavioral ecology of the recorded species. Recordings of wild hourglass (Lagenorhynchus cruciger) and Hector's dolphins (Cephalorhynchus hectori) were made in the Drake Passage (between Tierra del Fuego and the Antarctic Peninsular) and Banks Peninsular (Akaroa Harbour, New Zealand) with a four element hydrophone array. Analysis of source parameters shows that both species produce narrow band high-frequency (NBHF) echolocation clicks. Coastal Hector's dolphins produce clicks with a mean peak frequency of 129 kHz, 3 dB bandwidth of 20 kHz, 57 micros, 10 dB duration, and mean apparent source level (ASL) of 177 dB re 1 microPa(p.-p.). The oceanic hourglass dolphins produce clicks with mean peak frequency of 126 kHz, 3 dB bandwidth of 8 kHz, 116 micros, 10 dB duration, and a mean estimated ASL of 197 dB re 1 microPa(p.-p.). Thus, hourglass dolphins apparently produce clicks of higher source level, which should allow them to detect prey at more than twice the distance compared to Hector's dolphins. The observed source parameter differences within these two NBHF species may be an adaptation to a coastal cluttered environment versus a deep water, pelagic habitat. PMID:19275335

Kyhn, Line A; Tougaard, J; Jensen, F; Wahlberg, M; Stone, G; Yoshinaga, A; Beedholm, K; Madsen, P T

2009-03-01

303

Clicking in a Killer Whale Habitat: Narrow-Band, High-Frequency Biosonar Clicks of Harbour Porpoise (Phocoena phocoena) and Dall’s Porpoise (Phocoenoides dalli)  

PubMed Central

Odontocetes produce a range of different echolocation clicks but four groups in different families have converged on producing the same stereotyped narrow band high frequency (NBHF) click. In microchiropteran bats, sympatric species have evolved the use of different acoustic niches and subtly different echolocation signals to avoid competition among species. In this study, we examined whether similar adaptations are at play among sympatric porpoise species that use NBHF echolocation clicks. We used a six-element hydrophone array to record harbour and Dall’s porpoises in British Columbia (BC), Canada, and harbour porpoises in Denmark. The click source properties of all porpoise groups were remarkably similar and had an average directivity index of 25 dB. Yet there was a small, but consistent and significant 4 kHz difference in centroid frequency between sympatric Dall’s (137±3 kHz) and Canadian harbour porpoises (141±2 kHz). Danish harbour porpoise clicks (136±3 kHz) were more similar to Dall’s porpoise than to their conspecifics in Canada. We suggest that the spectral differences in echolocation clicks between the sympatric porpoises are consistent with evolution of a prezygotic isolating barrier (i.e., character displacement) to avoid hybridization of sympatric species. In practical terms, these spectral differences have immediate application to passive acoustic monitoring. PMID:23723996

Kyhn, Line A.; Tougaard, Jakob; Beedholm, Kristian; Jensen, Frants H.; Ashe, Erin; Williams, Rob; Madsen, Peter T.

2013-01-01

304

Ground-based Pa$\\alpha$ Narrow-band Imaging of Local Luminous Infrared Galaxies I: Star Formation Rates and Surface Densities  

E-print Network

Luminous infrared galaxies (LIRGs) are enshrouded by a large amount of dust, produced by their active star formation, and it is difficult to measure their activity in the optical wavelength. We have carried out Pa$\\alpha$ narrow-band imaging observations of 38 nearby star-forming galaxies including 33 LIRGs listed in $IRAS$ RBGS catalog with the Atacama Near InfraRed camera (ANIR) on the University of Tokyo Atacama Observatory (TAO) 1.0 m telescope (miniTAO). Star formation rates (SFRs) estimated from the Pa$\\alpha$ fluxes, corrected for dust extinction using the Balmer Decrement Method (typically $A_V$ $\\sim$ 4.3 mag), show a good correlation with those from the bolometric infrared luminosity of $IRAS$ data within a scatter of 0.27 dex. This suggests that the correction of dust extinction for Pa$\\alpha$ flux is sufficient in our sample. We measure the physical sizes and the surface density of infrared luminosities ($\\Sigma_{L(\\mathrm{IR})}$) and $SFR$ ($\\Sigma_{SFR}$) of star-forming region for individual ga...

Tateuchi, Ken; Motohara, Kentaro; Takahashi, Hidenori; Kato, Natsuko Mitani; Kitagawa, Yutaro; Todo, Soya; Toshikawa, Koji; Sako, Shigeyuki; Uchimoto, Yuka K; Ohsawa, Ryou; Asano, Kentaro; Ita, Yoshifusa; Kamizuka, Takafumi; Komugi, Shinya; Koshida, Shintaro; Manabe, Sho; Nakamura, Tomohiko; Nakashima, Asami; Okada, Kazushi; Takagi, Toshinobu; Tanabé, Toshihiko; Uchiyama, Mizuho; Aoki, Tsutomu; Doi, Mamoru; Handa, Toshihiro; Kawara, Kimiaki; Kohno, Kotaro; Minezaki, Takeo; Miyata, Takashi; Morokuma, Tomoki; Soyano, Takeo; Tamura, Yoichi; Tanaka, Masuo; Tarusawa, Ken'ichi; Yoshii, Yuzuru

2014-01-01

305

Narrow band imaging with magnification can pick up esophageal squamous cell carcinoma more efficiently than lugol chromoendoscopy in patients after chemoradiotherapy.  

PubMed

Aim. Little is known about the usefulness of narrow band imaging (NBI) for surveillance of patients after chemoradiotherapy for esophageal neoplasia. Its usefulness in detecting esophageal squamous cell carcinoma (SCC) or high-grade intraepithelial neoplasia (HGIN) in these patients was retrospectively compared to Lugol chromoendoscopy. Patients and Methods. We assessed the diagnostic ability of NBI with magnification based on the biopsy specimens obtained from iodine-unstained lesions. Seventy-two iodine-unstained lesions were biopsied and consecutively enrolled for this study. The lesions were divided into NBI positive and NBI negative. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of NBI with magnification and PPV of Lugol chromoendoscopy was calculated using histological assessment as a gold standard. Results. Forty-six endoscopic examinations using NBI with magnification followed by Lugol chromoendoscopy were performed to 28 patients. The prevalence of SCC and HGIN was 21.4%. Sensitivity, specificity, PPV, NPV, and accuracy of NBI were 100.0%, 98.5%, 85.7%, 100%, and 98.6%, respectively. On the contrary, PPV of Lugol chromoendoscopy were 8.3%. Compared to Lugol chromoendoscopy, NBI with magnification showed equal sensitivity and significantly higher PPV (P < 0.0001). Conclusion. NBI with magnification would be able to pick up esophageal neoplasia more efficiently than Lugol chromoendoscopy in patients after chemoradiotherapy. PMID:23476110

Asada-Hirayama, Itsuko; Kodashima, Shinya; Fujishiro, Mitsuhiro; Ono, Satoshi; Niimi, Keiko; Mochizuki, Satoshi; Konno-Shimizu, Maki; Mikami-Matsuda, Rie; Minatsuki, Chihiro; Nakayama, Chiemi; Takahashi, Yu; Yamamichi, Nobutake; Koike, Kazuhiko

2013-01-01

306

Evaluation of the Efficacy of Topical Tetracycline in Enhancing the Effect of Narrow Band UVB against Vitiligo: A Double-Blind, Randomized, Placebo-Controlled Clinical Trial  

PubMed Central

Background. Vitiligo is a pigmentary disorder characterized by depigmented macules due to absence of melanocytes. Increased levels of tumor necrosis factor alpha and interleukin-1 in the epidermis of lesions may play a role in keratinocyte apoptosis and less production of melanogenic cytokines. Tetracyclines reduce production of tumor necrosis factor alpha and interleukin-1. Objective. To evaluate the effect of topical tetracycline on vitiligo patients on phototherapy. Methods. Thirty cases of generalized stable vitiligo were chosen randomly and pigmentation of two assigned lesions on right and left sides (same size and location) was determined by vitiligo area severity index, and medication and placebo were randomly assigned to be applied twice daily on either right or left side, respectively. Images were taken of the lesions at the end of the 4th, 8th, and 12th weeks and pigmentations were compared to baseline using aforementioned index. The patients also took narrow band ultraviolet B two to three times a week. Results. Mean pigmentation, based on vitiligo area severity index, changed significantly from 90.1667 to 86.6667 (P = 0.026) and on placebo side from 89.6667 to 86.8333 (P = 0.026). There was no significant difference between medication and placebo sides in terms of pigmentation (P = 0.566). Conclusions. No significant difference in improving repigmentation between medication and placebo sides was seen. PMID:24665368

Kalafi, Amir; Jowkar, Farideh

2014-01-01

307

Ground-based detections of thermal emission from the dense hot Jupiter WASP-43b in H and Ks-bands  

E-print Network

We report new detections of thermal emission from the transiting hot Jupiter WASP-43b in the H and Ks-bands as observed at secondary eclipses. The observations were made with the WIRCam instrument on the CFHT. We obtained a secondary eclipse depth of 0.103$_{-0.017}^{+0.017}%$ and 0.194$_{-0.029}^{+0.029}%$ in the H and Ks-bands, respectively. The Ks band depth is consistent with previous measurement in the narrow band centered at 2.09um by Gillon et al. (2012). Our eclipse depths in both bands are consistent with a blackbody spectrum with a temperature of ~1850 K, slightly higher than the dayside equilibrium temperature without day-night energy redistribution. Based on theoretical models of the dayside atmosphere of WASP-43b, our data constrain the day-night energy redistribution in the planet to be $\\lesssim 15-25$%, depending on the metal content in the atmosphere. Combined with energy balance arguments our data suggest that a strong temperature inversion is unlikely in the dayside atmosphere of WASP-43b. ...

Wang, Wei; Madhusudhan, Nikku; Chen, Guo; Zhao, Gang; Henning, Thomas

2013-01-01

308

GROUND-BASED DETECTIONS OF THERMAL EMISSION FROM THE DENSE HOT JUPITER WASP-43b IN THE H AND K{sub s} BANDS  

SciTech Connect

We report new detections of thermal emission from the transiting hot Jupiter WASP-43b in the H and K{sub s} bands as observed at secondary eclipses. The observations were made with the WIRCam instrument on the Canada-France-Hawaii Telescope. We obtained a secondary eclipse depth of 0.103{sub -0.017}{sup +0.017}%$ and 0.194{sub -0.029}{sup +0.029} in the H and K{sub s} bands, respectively. The K{sub s}-band depth is consistent with the previous measurement in the narrow band centered at 2.09 {mu}m by Gillon et al. Our eclipse depths in both bands are consistent with a blackbody spectrum with a temperature of {approx}1850 K, slightly higher than the dayside equilibrium temperature without day-night energy redistribution. Based on theoretical models of the dayside atmosphere of WASP-43b, our data constrain the day-night energy redistribution in the planet to be {approx}< 15%-25%, depending on the metal content in the atmosphere. Combined with energy balance arguments, our data suggest that a strong temperature inversion is unlikely in the dayside atmosphere of WASP-43b. However, a weak inversion cannot be strictly ruled out at the current time. Future observations are required to place detailed constraints on the chemical composition of the atmosphere.

Wang, W.; Zhao, G. [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Van Boekel, R.; Henning, Th. [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Madhusudhan, N. [Department of Physics and Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Chen, G., E-mail: wangw@nao.cas.cn [Purple Mountain Observatory, Chinese Academy of Sciences, West Beijing Road, Nanjing 210008 (China)

2013-06-10

309

Updated modeling of the N2 LBH band emissions in the Earth’s thermosphere  

NASA Astrophysics Data System (ADS)

Much of the information derived from remote sensing of the thermosphere depends on our understanding of the N2 Lyman-Birge-Hopfield (LBH) band emissions. This emission is essential to techniques used to derive atomic oxygen to molecular nitrogen (O/N2) density ratios, to molecular nitrogen densities and to remotely sensing the temperature of the lower thermosphere. There has been uncertainty and debate about the importance of excitation of the emission by cascade of excitation from other states of N2. Previous modeling results for the LBH band emissions from the Earth’s upper atmosphere have made approximations to either the cascading between the singlet states or the calculation of the photoelectron spectrum. Consequently, direct excitation, scaled to approximate the expected effects of excitation by cascade, is used when deriving information from atmospheric observations. Now, a model of the cascading, Intrasystem Cascade Excitation (ICE), has been coupled with a recent model, GLOW, for calculating the photoelectron spectrum. With this combination of models, the approximations previously used can be avoided. In addition to coupling the two models, the most recent N2 cross section information now available have been incorporated into the calculation. These updated calculation are generally consistent with earlier calculations; however, when the recent cross sections are incorporated, the brightness of the LBH bands is enhanced less than that reported for earlier calculations.

Eastes, R.; Kulshreshth, A.

2009-12-01

310

Modeled and observed N2 Lyman-Birge-Hopfield band emissions: A comparison  

NASA Astrophysics Data System (ADS)

A thorough understanding of how the N2 Lyman-Birge-Hopfield (LBH) band emissions vary with altitude is essential to the use of this emission by space-based remote sensors. In this paper, model-to-model comparisons are first performed to elucidate the influence of the solar irradiance spectrum, intrasystem cascade excitation, and O2 photoabsorption on the limb profile. Next, the observed LBH emissions measured by the High resolution Ionospheric and Thermospheric Spectrograph aboard the Advanced Research and Global Observation Satellite are compared with modeled LBH limb profiles to determine which combination of parameters provides the best agreement. The analysis concentrates on the altitude dependence of the LBH (1,1) band, the brightest LBH emission in the observations. In the analysis, satellite drag data are used to constrain the neutral densities used for the data-to-model comparisons. For the average limb profiles on two of the three days analyzed (28, 29, and 30 July 2001), calculations using direct excitation alone give slightly better agreement with the observations than did calculations with cascading between the singlet electronic N2 states (a1?g, a??-u, and w1?u) however, the differences between the observed profiles and either model are possibly greater than the differences between the models. Nevertheless, both models give excellent agreement with the observations, indicating that current models provide an adequate description of the altitude variation of the N2 LBH (1,1) band emissions. Consequently, when using the LBH bands to remotely sense thermospheric temperatures, which can be used to provide an unprecedented view of the thermosphere, the temperatures derived have a negligible dependence on the model used.

Eastes, R. W.; Murray, D. J.; Aksnes, A.; Budzien, S. A.; Daniell, R. E.; Krywonos, A.

2011-12-01

311

Review of Terra MODIS thermal emissive band L1B radiometric performance  

NASA Astrophysics Data System (ADS)

The MODerate-resolution Imaging Spectroradiometer (MODIS) on NASA's Earth Observing System Terra satellite, launched into orbit on 18 December 1999, will have a "first light" 15th anniversary on 24 February 2015. For nearly 15 years the MODIS instrument has provided radiances in all spectral bands. Though some detectors have fallen below SNR thresholds, the vast majority of spectral bands continue to provide high quality L1B measurements for use in L2 science algorithms supporting global climate research. Radiometric accuracy of the Terra MODIS thermal emissive bands (TEBs) in the C6 L1B product has been assessed using various approaches over the nearly 15 year Terra MODIS data record, including comparisons with instruments on the ground, in aircraft under-flights, and on other satellites. All of these approaches contribute to the understanding of the Terra MODIS radiometric L1B performance. Early in the lifetime of Terra, ground-based measurements and NASA ER-2 aircraft under-flights revealed that TEBs in the infrared window ("window" bands) are well calibrated and performing within accuracy specifications. The ER-2 under-flights also suggested that many atmospheric bands may be performing outside of specification, especially LWIR CO2 sensitive bands that are subject to optical crosstalk, although analysis uncertainties are larger for atmospheric bands. Beginning in 2007, MetOp-A IASI observations were used to evaluate Terra MODIS TEB performance through Simultaneous Nadir Overpass (SNO) comparisons. These inter-satellite comparisons largely affirm the early aircraft and ground-based evaluations, showing that all Terra MODIS window bands have small biases, minimal trending, and minor detector and mirror side striping over the 2007-2013 timeframe. Most atmospheric bands are performing satisfactorily near to specification; however, biases, striping and trending are large and significantly out of specification in the water vapor sensitive band 27 and ozone sensitive band 30 while the CO2 sensitive band 36 bias significantly exceeds specification. The investigation has found that an effective spectral shift significantly reduces biases and scene temperature dependence (but not trends) in most atmospheric bands, bringing them closer to, if not within, specification.

Moeller, Chris; Menzel, W. P.; Quinn, Greg

2014-09-01

312

VIIRS thermal emissive bands on-orbit calibration coefficient performance using vicarious calibration results  

NASA Astrophysics Data System (ADS)

The Visible Infrared Imager Radiometer Suite (VIIRS), a primary sensor on-board the Suomi-National Polar-orbiting Partnership (SNPP) spacecraft, was launched October 28, 2011. It has 22 bands: 7 thermal emissive bands (TEBs), 14 reflective solar bands (RSBs) and a Day Night Band (DNB). The TEBs cover the spectral wavelengths between 3.7 to 12 ?m and have two 371 m and five 742 m spatial resolution bands. A VIIRS Key Performance Parameter (KPP) is the sea surface temperature (SST) which uses bands M12 (3.7 ?m), M15 (10.8 ?m) and M16's (12.0 ?m) calibrated Science Data Records (SDRs). The TEB SDRs rely on pre-launch calibration coefficients used in a quadratic algorithm to convert the detector's response to calibrated radiance. This paper will evaluate the performance of these prelaunch calibration coefficients using vicarious calibration information from the Cross-track Infrared Sounder (CrIS) also onboard the SNPP spacecraft and the Infrared Atmospheric Sounding Interferometer (IASI) on-board the Meteorological Operational (MetOp) satellite. Changes to the pre-launch calibration coefficients' offset term c0 to improve the SDR's performance at cold scene temperatures will also be discussed.

Moyer, D.; Moeller, C.; De Luccia, F.

2013-09-01

313

Modeling Altitude Profiles of the N2 Lyman-Birge-Hopfield Band Emissions  

NASA Astrophysics Data System (ADS)

Space-based remote sensing of the N2 Lyman-Birge-Hopfield (LBH) band emissions provides valuable insight about the Earth's environment. In this study we investigate the ability of the cascade model to reproduce the LBH limb profiles, by comparing model calculations with observations from the High resolution Ionospheric and Thermospheric Spectrograph (HITS) aboard the Advanced Research and Global Observation Satellite (ARGOS). Also, we examine how the different models existing to infer the LBH emissions match in different altitude regions. While most models only take direct excitation into account, the cascade code also includes radiative and collisional cascade contributions.

Murray, J.; Eastes, R.; Aksnes, A.; Budzien, S.; Daniell, R.; Dymond, K.

2005-12-01

314

Nitric oxide delta band emission in the earth's atmosphere - Comparison of a measurement and a theory  

NASA Technical Reports Server (NTRS)

Attention is given to the altitude dependent emission rate in the delta-bands of nitric oxide as measured in the earth's atmosphere at night by a scanning ultraviolet spectrometer. It is noted that the reaction responsible is the two-body association of nitrogen and oxygen atoms. The measurements show a vertical intensity beneath the layer for the delta-band system of 19 R. The horizontal emission rate is found to increase from 70 R at 117 km to 140 R at 150 km. The data are analyzed with a one-dimensional, time-dependent, vertical-transport model of odd nitrogen photochemistry. The calculated and measured intensities agree so long as the quenching of N(2D) by atomic oxygen is near 5 x 10 to the -13 cu cm/sec.

Rusch, D. W.; Sharp, W. E.

1981-01-01

315

Simplified classification of capillary pattern in barrett esophagus using magnifying endoscopy with narrow band imaging: implications for malignant potential and interobserver agreement.  

PubMed

The classification of Barrett esophagus (BE) using magnifying endoscopy with narrow band imaging (ME-NBI) is not widely used in clinical settings because of its complexity. To establish a new simplified available classification using ME-NBI.We conducted a cross-sectional study in a single-referral center. One hundred eight consecutive patients with BE using ME-NBI and crystal violet (CV) chromoendoscopy, and histological findings were enrolled. BE areas observed by ME-NBI were classified as type I or II on the basis of capillary pattern (CP), and as closed or open type on the basis of a mucosal pit pattern using CV chromoendoscopy; then, biopsy samples were obtained. We evaluated the relation between CP and pit pattern, expression of the factors with malignant potential, percentage of microvascular density, and interobserver agreement.One hundred thirty lesions from 91 patients were analyzed. Type II CP had more open type pit pattern areas and significantly greater microvascular density than type I. The presence of dysplasia, specialized intestinal metaplasia, expressions of COX-2, CDX2, and CD34, and PCNA index were significantly higher in type II, whereas the multivariate analysis showed that type II was the best predictor for the presence of dysplasia (OR 11.14), CD34 expression (OR 3.60), and PCNA (OR 3.29). Interobserver agreement for this classification was substantial (??=?0.66).A simplified CP classification based on observation with ME-NBI is presented. Our results indicate that the classification may be useful for surveillance of BE with high malignant potential. PMID:25621687

Uno, Goichi; Ishimura, Norihisa; Tada, Yasumasa; Tamagawa, Yuji; Yuki, Takafumi; Matsushita, Takashi; Ishihara, Shunji; Amano, Yuji; Maruyama, Riruke; Kinoshita, Yoshikazu

2015-01-01

316

Effective optical identification of type “0-IIb” early gastric cancer with narrow band imaging magnification endoscopy, successfully treated by endoscopic submucosal dissection  

PubMed Central

Background Endoscopic submucosal dissection (ESD) is currently considered the minimal invasive endoscopic treatment for early gastric cancer. Most superficial gastric neoplastic lesions are depressed type “0-IIc” (70-80%), while totally flat, classified as type “0-IIb” early gastric cancer, is rarely reported (0.4%). The aim of the present study was to assess the efficacy of narrow band imaging (NBI) magnification endoscopy in identifying type “0-IIb” early gastric cancer and ESD treatment with curative intention. Methods Twelve of 615 (2%) patients (10 males, median 72 years), treated by ESD at our center, were diagnosed as type “0-IIb” gastric cancer. Ten had exclusively type “0-IIb”, while two had combined types “0-IIb+IIc” and “0-IIa+IIb” gastric cancer. Initial diagnosis was made during screening gastroscopy, while NBI magnification endoscopy combined with indigo-carmine chromoendoscopy were also used. Results White light endoscopy showed only superficial redness. One patient with signet-ring carcinoma showed whitish appearance. Indigo-carmine chromoendoscopy showed better visualization, while NBI magnification endoscopy revealed abnormal mucosal microsurface and microvascular findings which enabled border marking. ESD with curative intention was completed without complications. Histological examination showed complete (R0) resection, in 10 patients (83%). One patient with positive margins received additional surgery (8%). Mean procedure time was 149 (range 60-190) min. One to six years post-ESD all patients remain alive. Conclusions ESD is considered a safe and effective curative treatment for type “0-IIb” gastric cancer, resulting in long-term disease-free survival. NBI magnification endoscopy is effective for accurate optical identification and border marking of type “0-IIb” early gastric cancer. PMID:25609014

Eleftheriadis, Nikolas; Inoue, ?aruhiro; Ikeda, Haruo; Onimaru, Manabu; Yoshida, Akira; Maselli, Roberta; Santi, Grace; Hamatani, Shigeharu; Kudo, Shin-ei

2015-01-01

317

Usefulness of Non-Magnifying Narrow-Band Imaging in Screening of Early Esophageal Squamous Cell Carcinoma: A Prospective Comparative Study Using Propensity Score Matching  

PubMed Central

OBJECTIVES: The usefulness of non-magnifying endoscopy with narrow-band imaging (NBI; NM-NBI) in the screening of early esophageal squamous cell carcinoma (SCC) and high-grade intraepithelial neoplasia (HGIN) remains unclear. Here, we aimed to compare NM-NBI and chromoendoscopy with iodine staining (CE-Iodine) in terms of the diagnostic performance, and to evaluate the usefulness of NM-NBI in detecting early esophageal SCC. METHODS: We prospectively enrolled 202 consecutive patients (male/female=180/22; median age, 67 years) with high-risk factors for esophageal SCC. All patients received endoscopic examination with NM-NBI and CE-Iodine to screen for early esophageal SCC or HGIN. We conducted the examinations sequentially, and calculated the accuracy, sensitivity, and specificity through a per-lesion-based analysis. A propensity score matching analysis was performed to reduce the effects of selection bias, and we compared the respective outcomes according to NM-NBI and CE-Iodine after matching. RESULTS: The accuracy, sensitivity, and specificity of NM-NBI were 77.0, 88.3, and 75.2%, respectively, and those for unstained areas by CE-Iodine were 68.0, 94.2, and 64.0, respectively. The accuracy and specificity of NM-NBI were superior to those of CE-Iodine (P=0.03 and P=0.01, respectively). However, the sensitivity did not significantly differ between NM-NBI and CE-Iodine (P=0.67). The accuracy and specificity of NM-NBI before matching were superior to those of CE-Iodine after matching (P=0.04 and P=0.03). CONCLUSIONS: NM-NBI was useful and reliable for the diagnosis of esophageal SCC and can be a promising screening strategy for early esophageal SCC. PMID:24751580

Nagami, Yasuaki; Tominaga, Kazunari; Machida, Hirohisa; Nakatani, Masami; Kameda, Natsuhiko; Sugimori, Satoshi; Okazaki, Hirotoshi; Tanigawa, Tetsuya; Yamagami, Hirokazu; Kubo, Naoshi; Shiba, Masatsugu; Watanabe, Kenji; Watanabe, Toshio; Iguchi, Hiroyoshi; Fujiwara, Yasuhiro; Ohira, Masaichi; Hirakawa, Kosei; Arakawa, Tetsuo

2014-01-01

318

Early Detection of Superficial Squamous Cell Carcinoma in the Head and Neck Region and Esophagus by Narrow Band Imaging: A Multicenter Randomized Controlled Trial  

PubMed Central

Purpose Most of the esophageal squamous cell carcinomas (ESCCs) and cancers of the head and neck (H&N) region are diagnosed at later stages. To achieve better survival, early detection is necessary. We compared the real-time diagnostic yield of superficial cancer in these regions between conventional white light imaging (WLI) and narrow band imaging (NBI) in high-risk patients. Patients and Methods In a multicenter, prospective, randomized controlled trial, 320 patients with ESCC were randomly assigned to primary WLI followed by NBI (n = 162) or primary NBI followed by WLI (n = 158) in a back-to-back fashion. The primary aim was to compare the real-time detection rates of superficial cancer in the H&N region and the esophagus between WLI and NBI. The secondary aim was to evaluate the diagnostic accuracy of these techniques. Results NBI detected superficial cancer more frequently than did WLI in both the H&N region and the esophagus (100% v 8%, P < .001; 97% v 55%, P < .001, respectively). The sensitivity of NBI for diagnosis of superficial cancer was 100% and 97.2% in the H&N region and the esophagus, respectively. The accuracy of NBI for diagnosis of superficial cancer was 86.7% and 88.9% in these regions, respectively. The sensitivity and accuracy were significantly higher using NBI than WLI in both regions (P < .001 and P = .02 for the H&N region; P < .001 for both measures for the esophagus, respectively). Conclusion NBI could be the standard examination for the early detection of superficial cancer in the H&N region and the esophagus. PMID:20177025

Muto, Manabu; Minashi, Keiko; Yano, Tomonori; Saito, Yutaka; Oda, Ichiro; Nonaka, Satoru; Omori, Tai; Sugiura, Hitoshi; Goda, Kenichi; Kaise, Mitsuru; Inoue, Haruhiro; Ishikawa, Hideki; Ochiai, Atsushi; Shimoda, Tadakazu; Watanabe, Hidenobu; Tajiri, Hisao; Saito, Daizo

2010-01-01

319

Four emission bands from a mixed-ligand iridium complex IrQ(ppy)2 at room temperature  

NASA Astrophysics Data System (ADS)

Four photoluminescence bands are observed from iridium complex in UV, violet, green, and red spectral regions at room temperature. Such a multiple emission is found from a mixed-ligand iridium(III) complex, (8-quinolinolato) bis(2-phenylpyridyl) iridium IrQ(ppy)2, which consists of IrQ and Ir(ppy)2 components (Q: 8-quinolinolato, ppy: phenylpyridyl). Of the four emission bands, the UV emission band with maximum at about 330 nm and the red emission band are attributed to the ligand-centered (1LC) 1n?* and metal-to-ligand charge transfer (3MLCT) 3(??*) states from IrQ, respectively, while the violet emission band with maximum at about 400 nm and the green emission band at about 513 nm are attributed to the 1LC 1(n?*) and 3MLCT 3??* states from Ir(ppy). It is suggested that (1) IrQ and Ir(ppy) generate their own emissions by the inefficient Förster energy transfer between IrQ and Ir(ppy) due to the orientation factor of nearly zero, and (2) each of IrQ and Ir(ppy) gives rise to two emissions from the singlet and triplet states by the inefficient intersystem crossing.

Tsuboi, Taiju; Huang, Duo-Fong; Chow, Tahsin J.; Huang, Wei

2014-08-01

320

A Theory Attributing Optical Diffuse Interstellar Absorption Bands, ``Unidentified Infrared'' Emission Bands, and Cloud Reddening to H 2 Nonlinear Absorption  

NASA Astrophysics Data System (ADS)

A theory is described that attributes the diffuse interstellar absorption bands (DIBs) to coherently driven two-photon absorption by H2 molecules present in sheetlike clouds located near hot stars. Results from three-level nonlinear spectroscopy are used to argue that vacuum ultraviolet (VUV) photons from the star impinging on the H2-containing cloud will be primarily absorbed in simultaneous two-photon (Raman-type) transitions, resulting in the build-up of coherent VUV Stokes-wave radiation in the "plane" of the H2-containing cloud on the transitions [Cn ? X0; P(2) and P(3); n = 0-5] and on some of the transitions [Bn ? X0, P(2) and P(3)]. Via this in-plane VUV Stokes-wave radiation, parahydrogen molecules in the (X0, J" = 2) level and ortho-hydrogen molecules in the (X0, J" = 3) level are coherently excited to levels [Cn?u+); J' = 1 and 2; n = 0-5] and [Bn, J' = 1 and 2], which thus serve as the intermediate states in resonantly enhanced, coherently driven, two-photon absorption. The DIBs result from visible light from the star being simultaneously absorbed in "second step" transitions from the coherently excited (C, B)-state levels to various singlet gerade state levels. In-plane coherent VUV Stokes-wave radiation at [Cn ? X0; P(2) and P(3); n = 1-5] can also act to produce in-plane coherent IR radiation via stimulated Raman scattering processes terminating on various EF singlet gerade levels. Striking coincidences are shown to exist between frequencies of IR Stokes-wave transitions expected to be strong and those of the so-called unidentified infrared emission bands (UIBs). Assuming a common identity, assignments are offered for most of the known UIBs. More than 70 sharp DIBs are assigned to transitions from B- and C-state levels to levels of singlet gerade states. On the basis of in-plane four-wave mixing of VUV and IR-Stokes-waves radiation (i.e., four-wave parametric generation), the most prominent features seen in the emission spectrum of the Red Rectangle are also explained. It is furthermore indicated that cloud reddening should be an additional manifestation of the presence of intense, in-plane, VUV Stokes-wave radiation.

Sorokin, Peter P.; Glownia, James H.

1996-12-01

321

On the yellow-band emission in CdS films  

NASA Astrophysics Data System (ADS)

CdS polycrystalline thin films were prepared by the chemical bath deposition (CBD) method on glass substrates. X-ray diffraction (XRD) studies show that the films grow in the cubic zinc-blende crystalline phase. Upon thermal annealing (TA) in Ar+S2 flux at normal pressure in the temperature range 240-510 °C, the evolution of the transformation into the hexagonal wurtzite phase is observed. This hexagonal crystalline structure is the stable phase. From XRD diagrams the phase transition can be appreciated to occur upon TA at approximately 300 °C. Photoluminescence (PL) data prove that the green-emission band is present for well-defined phases - cubic or hexagonal ones. A second band located at 2.2 eV appears for samples near the transition region. This band at 2.2 eV, called the yellow band, has already been reported to be associated with interstitial Cd atoms. A model for this yellow-band-mechanism formation, arising during the phase transformation, has been proposed based on Frenkel-pair creation.

Lozada-Morales, R.; Zelaya-Angel, O.; Torres-Delgado, G.

322

Origin of the low-energy emission band in epitaxially grown para-sexiphenyl nanocrystallites  

NASA Astrophysics Data System (ADS)

A comparative study of steady-state and time-resolved photoluminescence of para-sexiphenyl (PSP) films grown by organic molecular beam epitaxy (OMBE) and hot wall epitaxy (HWE) under comparable conditions is presented. Using different template substrates [mica(001) and KCl(001) surfaces] as well as different OMBE growth conditions has enabled us to vary greatly the morphology of the PSP crystallites while keeping their chemical structure virtually untouched. We prove that the broad redshifted emission band has a structure-related origin rather than being due to monomolecular oxidative defects. We conclude that the growth conditions and type of template substrate impacts substantially on the film morphology (measured by atomic force microscopy) and emission properties of the PSP films. The relative intensity of the defect emission band observed in the delayed spectra was found to correlate with the structural quality of PSP crystallites. In particular, the defect emission has been found to be drastically suppressed when (i) a KCl template substrate was used instead of mica in HWE-grown films, and (ii) in the OMBE-grown films dominated by growth mounds composed of upright standing molecules as opposed to the films consisting of crystallites formed by molecules lying parallel to the substrate.

Kadashchuk, A.; Schols, S.; Heremans, P.; Skryshevski, Yu.; Piryatinski, Yu.; Beinik, I.; Teichert, C.; Hernandez-Sosa, G.; Sitter, H.; Andreev, A.; Frank, P.; Winkler, A.

2009-02-01

323

Origin of the low-energy emission band in epitaxially grown para-sexiphenyl nanocrystallites  

SciTech Connect

A comparative study of steady-state and time-resolved photoluminescence of para-sexiphenyl (PSP) films grown by organic molecular beam epitaxy (OMBE) and hot wall epitaxy (HWE) under comparable conditions is presented. Using different template substrates [mica(001) and KCl(001) surfaces] as well as different OMBE growth conditions has enabled us to vary greatly the morphology of the PSP crystallites while keeping their chemical structure virtually untouched. We prove that the broad redshifted emission band has a structure-related origin rather than being due to monomolecular oxidative defects. We conclude that the growth conditions and type of template substrate impacts substantially on the film morphology (measured by atomic force microscopy) and emission properties of the PSP films. The relative intensity of the defect emission band observed in the delayed spectra was found to correlate with the structural quality of PSP crystallites. In particular, the defect emission has been found to be drastically suppressed when (i) a KCl template substrate was used instead of mica in HWE-grown films, and (ii) in the OMBE-grown films dominated by growth mounds composed of upright standing molecules as opposed to the films consisting of crystallites formed by molecules lying parallel to the substrate.

Kadashchuk, A. [IMEC v.z.w., SOLO-PME, Kapeldreef 75, B-3001 Leuven (Belgium); Institute of Physics, National Academy of Science of Ukraine, Kiev 03028 (Ukraine); Schols, S. [IMEC v.z.w., SOLO-PME, Kapeldreef 75, B-3001 Leuven (Belgium); Department of Electrical Engineering, Katholieke Universiteit Leuven, B-3001 Leuven (Belgium); Heremans, P. [IMEC v.z.w., SOLO-PME, Kapeldreef 75, B-3001 Leuven (Belgium); Skryshevski, Yu.; Piryatinski, Yu. [Institute of Physics, National Academy of Science of Ukraine, Kiev 03028 (Ukraine); Beinik, I.; Teichert, C. [Institute of Physics, University of Leoben, A-8700 Leoben (Austria); Hernandez-Sosa, G.; Sitter, H. [Institute of Semiconductor and Solid State Physics, University of Linz, A-4040 Linz (Austria); Andreev, A. [Nanoindent Technologies AG, A-4020 Linz (Austria); Frank, P.; Winkler, A. [Graz University of Technology, A-8010 Graz (Austria)

2009-02-28

324

Rain effect on Aquarius L-band Emissivity and Backscatter Model Functions  

NASA Astrophysics Data System (ADS)

Remote sensing of sea surface salinity (SSS) is being performed by Aquarius and SMOS missions, which are using L-band radiometry to sense the microwave emissions from sea surfaces. To enable accurate SSS retrieval, it is essential to correct the impact of sea surface roughness on L-band brightness temperatures. In addition, the impact of rain has to be carefully assessed and accounted for. Although the atmospheric attenuation caused by raindrops are likely negligible at 1.4GHz, other factors must be considered because they may have indirect but important contribution to the surface roughness and consequently L-band brightness temperatures. For example, the wind speed dependent roughness correction will be corrupted when rain striking the water, creating rings, stalks, and crowns from which the signal scatters. It is also unknown how long the freshwater stays at surface while through the oceanic mixing process at various regions over global oceans. We collocated the Aquarius L-band data with various wind products, including SSM/I, NCEP, ASCAT and WindSAT, as well as the SSM/I and WindSAT rain products. During the first four months of Aquarius mission, near 1.9 million pixels are identified under rain conditions by either SSM/I or WindSAT. We derived the L-band emissivity and backscatter geophysical model functions (GMF), parameterized by SSM/I and NCEP winds for rain-free conditions. However, the residual ocean surface emissivity (the Aquarius measured minus the rain-free model predictions) reveals profound resemblance with global precipitation pattern. In region dominated by rain, e.g. ITCZ, northern hemisphere storm track, and Indian Ocean partially under the influence of summer monsoon, the GMF built using rain free data underestimates excess emissivity about 0.5 to 1 K. The dependence of residual of emissivity and backscatter is shown as a function of wind speed and rain rate. A modified GMF is developed including rain rate as one of the parameters. Due to limited samples at heavy rain, we binned the data in four rain domains: rain free, light (0-2 mm/hr), moderate (2-5 mm/hr) and heavy (>5 mm/hr). Comparing the modeling coefficients with rain free GMF, the major changes introduced by rain is found to occur at low to medium wind speeds, and curves for different rain domains converge for high wind (beyond 15 m/s).

Tang, W.; Yueh, S. H.; Fore, A.; Neumann, G.; Hayashi, A.

2012-12-01

325

Thermal band selection for the PRISM instrument: 1. Analysis of emissivity-temperature separation algorithms  

NASA Astrophysics Data System (ADS)

One of the missions being planned by the European Space Agency (ESA) within the framework of its Earth Observation Programme is the Processes Research by Imaging Space Mission (PRISM). The PRISM instrument consists of a thermal sensor whose main objective is to retrieve accurate land surface temperatures (LST) and whose band positions are 3.5-4.1 ?m, 8.1-9.5 ?m, 10.3-11.3 ?m, and 11.5-12.5 ?m. We have studied the optimal design of this instrument to retrieve accurate LSTs. First, we have analyzed several emissivity-temperature separation methods (part 1) and atmospheric and emissivity correction algorithms (part 2). Finally, we have identified the optimal band configuration (part 3). This paper is the first of a series of three and addresses the question of the emissivity-temperature separability. Among all the existing algorithms, we have studied the "absolute methods," which are able to estimate the absolute value of emissivity at satellite scale and can yield better results in the emissivity estimate. These methods are the algorithm based on the temperature-independent thermal infrared spectral index (TISI), the alpha coefficients method, and the algorithms which use visible, near-infrared, and shortwave infrared data to estimate the thermal emissivity (vegetation cover method (VCM)). The study consisted of an analysis of both random and systematic errors of each method. The results indicate that emissivity can be obtained with an error of ±1.7-5% using the alpha coefficients, ±1.7-3% using the TISIs, and ±0.5-1.4% using the VCM, depending on the spectral region. In all cases the error decreases with wavelength, and the lowest errors are achieved in the 10-12 ?m spectral region, due to small variability of emissivity. It is necessary that the two first methods use radiosondes simultaneous with the satellite overpass to perform the atmospheric corrections on the thermal data; in addition, they show important sources of systematic errors, which will increase the uncertainty in the emissivity estimate (even in the best possible case). The VCM does not use radiosondes and does not present important sources of systematic error. It appears to be the procedure with the most favorable error propagation characteristics. Thus the VCM could be the most adequate method for retrieving the land surface emissivity (LSE), within the framework of this work.

Caselles, Vicente; Valor, Enric; Coll, CéSar; Rubio, Eva

1997-05-01

326

The microwave emission and transmission characters of deciduous forest at L-band  

NASA Astrophysics Data System (ADS)

Forest covers about 30% of earth surface, which plays an important role in global forecast and carbon cycle. Monitoring forest biomass, and retrieving soil moisture at forest area, are the main goals of most passive microwave sensors on satellite missions. L-band is the most sensitive frequency among all the frequencies due to its good penetration ability. Because of its variety of the size of scattering components, the complicated structures and species of forest, it is difficult to describe the scattering and attenuation characters of forest in modeling microwave emission at forest area. In this paper, we studied the emissivity and transmissivity of deciduous forest at L(1.4GHz) by model simulation and field experiment. The microwave emission model was based on Matrix-Doubling algorithm. The comparison between simulated emissivity and measured data collected during an experiment at Maryland, USA in 2007 was good. Since theoretical model like Matrix-Doubling is too complicated to be used in retrial application, we mapped the results of Matrix-Doubling to a simple 0th-order model, also called ?-? model, by setting the simulated emissivity to be the emissivity of 0th-order model at the same environment, which 2 unknown variables---opacity ? and effective single scattering albedo ? need to be determined. To valited ? (transmissivity of forest) simulated by Matrix-Doubling, we took an deciduous forest experiment by an L band microwave radiometer under trees at JingYueTan area, Changchun, Jilin Province in April to June in 2014. Thus the ? of forest can be determined. The matching results are presented in this paper. The relationship between LAI and forest microwave characters are discussed.

Zhang, Zhongjun; Yuan, Yu; Zheng, Xingming; Zhu, Xiaoming; Fu, Xiuli

2014-11-01

327

The dust sublimation radius as an outer envelope to the bulk of the narrow Fe Kalpha line emission in Type 1 AGN  

E-print Network

The Fe Kalpha emission line is the most ubiquitous feature in the X-ray spectra of active galactic nuclei (AGN), but the origin of its narrow core remains uncertain. Here, we investigate the connection between the sizes of the Fe Kalpha core emission regions and the measured sizes of the dusty tori in 13 local Type 1 AGN. The observed Fe Kalpha emission radii (R_fe) are determined from spectrally resolved line widths in X-ray grating spectra, and the dust sublimation radii (R_dust) are measured either from optical/near-infrared reverberation time lags or from resolved near-infrared interferometric data. This direct comparison shows that the dust sublimation radius forms an outer envelope to the bulk of the Fe Kalpha emission. R_fe matches R_dust well in the AGN with the best constrained line widths currently. In a significant fraction of objects without a clear narrow line core, R_fe is similar to, or smaller than the radius of the optical broad line region. These facts place important constraints on the toru...

Gandhi, Poshak; Kishimoto, Makoto

2015-01-01

328

Multiyear On-orbit Calibration and Performance of Terra MODIS Thermal Emissive Bands  

NASA Technical Reports Server (NTRS)

Since launch in December 1999, Terra MODIS has been making continuous Earth observations for more than seven years. It has produced a broad range of land, ocean, and atmospheric science data products for improvements in studies of global climate and environmental change. Among its 36 spectral bands, there are 20 reflective solar bands (RSB) and 16 thermal emissive bands (TEB). MODIS thermal emissive bands cover the mid-wave infrared (MWIR) and long-wave infrared (LWIR) spectral regions with wavelengths from 3.7 to 14.4pm. They are calibrated on-orbit using an on-board blackbody (BB) with its temperature measured by a set of thermistors on a scan-by-scan basis. This paper will provide a brief overview of MODIS TEB calibration and characterization methodologies and illustrate on-board BB functions and TEB performance over more than seven years of on-orbit operation and calibration. Discussions will be focused on TEB detector short-term stability and noise characterization, and changes in long-term response (or system gain). Results show that Terra MODIS BB operation has been extremely stable since launch. When operated at its nominal controlled temperature of 290K, the BB temperature variation is typically less than +0.30mK on a scan-by-scan basis and there has been no time-dependent temperature drift. In addition to excellent short-term stability, most TEB detectors continue to meet or exceed their specified noise characterization requirements, thus enabling calibration accuracy and science data product quality to be maintained. Excluding the noisy detectors identified pre-launch and those that occurred post-launch, the changes in TEB responses have been less than 0.7% on an annual basis. The optical leak corrections applied to bands 32-36 have been effective and stable over the entire mission

Xiong, Xiaoxiong; Chiang, Kwo-Fu; Wu, Aisheng; Barnes, William; Guenther, Bruce; Salomonson, Vincent

2007-01-01

329

The average GeV-band emission from gamma-ray bursts  

NASA Astrophysics Data System (ADS)

Aims: We analyze the emission in the 0.3-30 GeV energy range of gamma-ray bursts detected with the Fermi Gamma-ray Space Telescope. We concentrate on bursts that were previously only detected with the Gamma-Ray Burst Monitor in the keV energy range. These bursts will then be compared to the bursts that were individually detected with the Large Area Telescope at higher energies. Methods: To estimate the emission of faint GRBs we used nonstandard analysis methods and sum over many GRBs to find an average signal that is significantly above background level. We used a subsample of 99 GRBs listed in the Burst Catalog from the first two years of observation. Results: Although most are not individually detectable, the bursts not detected by the Large Area Telescope on average emit a significant flux in the energy range from 0.3 GeV to 30 GeV, but their cumulative energy fluence is only 8% of that of all GRBs. Likewise, the GeV-to-MeV flux ratio is less and the GeV-band spectra are softer. We confirm that the GeV-band emission lasts much longer than the emission found in the keV energy range. The average allsky energy flux from GRBs in the GeV band is 6.4 × 10-4 erg cm-2 yr-1 or only ~4% of the energy flux of cosmic rays above the ankle at 1018.6 eV.

Lange, J.; Pohl, M.

2013-03-01

330

EXAMINING THE BROADBAND EMISSION SPECTRUM OF WASP-19b: A NEW z-BAND ECLIPSE DETECTION  

SciTech Connect

WASP-19b is one of the most irradiated hot-Jupiters known. Its secondary eclipse is the deepest of all transiting planets and has been measured in multiple optical and infrared bands. We obtained a z-band eclipse observation with a measured depth of 0.080% {+-} 0.029%, using the 2 m Faulkes Telescope South, which is consistent with the results of previous observations. We combined our measurement of the z-band eclipse with previous observations to explore atmosphere models of WASP-19b that are consistent with its broadband spectrum. We use the VSTAR radiative transfer code to examine the effect of varying pressure-temperature profiles and C/O abundance ratios on the emission spectrum of the planet. We find that models with super-solar carbon enrichment best match the observations, which is consistent with previous model retrieval studies. We also include upper atmosphere haze as another dimension in the interpretation of exoplanet emission spectra and find that particles <0.5 {mu}m in size are unlikely to be present in WASP-19b.

Zhou, George; Bayliss, Daniel D. R. [Research School of Astronomy and Astrophysics, Australian National University, Cotter Rd, Weston Creek, ACT 2611 (Australia); Kedziora-Chudczer, Lucyna; Bailey, Jeremy, E-mail: george@mso.anu.edu.au [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia)

2013-09-10

331

Acoustic emission frequency discrimination  

NASA Technical Reports Server (NTRS)

In acoustic emission nondestructive testing, broadband frequency noise is distinguished from narrow banded acoustic emission signals, since the latter are valid events indicative of structural flaws in the material being examined. This is accomplished by separating out those signals which contain frequency components both within and beyond (either above or below) the range of valid acoustic emission events. Application to acoustic emission monitoring during nondestructive bond verification and proof loading of undensified tiles on the Space Shuttle Orbiter is considered.

Sugg, Frank E. (inventor); Graham, Lloyd J. (inventor)

1988-01-01

332

Study of instrument temperature effect on MODIS thermal emissive band responses  

NASA Astrophysics Data System (ADS)

The Moderate Resolution Imaging Spectroradiometer (MODIS) has 16 thermal emissive bands (TEB) over a spectral range from mid-wave infrared (MWIR) to long-wave infrared (LWIR), using photovoltaic (PV) HgCdTe detectors for bands 20-25 and 27-30 with wavelengths from 3.75?m to 9.73?m and photoconductive (PC) HgCdTe detectors for bands 31-36 with wavelengths from 11.0?m to 14.2?m. A total of 160 individual detectors, 10 per band, are distributed on the short- and mid-wave (SMIR) and LWIR cold focal-plane assemblies (CFPA) with temperature controlled at 83K. The instrument temperature affects the detector response and this effect varies with the detector type. Detector responses from on-orbit calibration and pre-launch measurements have been examined to characterize this effect. Results from this analysis show that, for the PV detectors on the SMIR CFPA, the detector responses (gains) increase with instrument temperature whereas the PC detector responses decrease with the instrument temperature. The calibration impact due to on-orbit changes in instrument temperatures is examined. On-orbit detector offset and nonlinear response characterization obtained from the on-boar blackbody (BB) warm-up and cool-down (WUCD) cycle is discussed. This investigation was performed for both Terra MODIS and Aqua MODIS.

Chang, Tiejun; Xiong, Xiaoxiong

2010-09-01

333

Deep Narrow-Band Imaging of M87: a Close Look at the Disk of Ionized Gas Fueling a Massive Black Hole  

NASA Astrophysics Data System (ADS)

M87 provides a unique example of a 100 pc scale disk of ionized gasfueling a massive black hole (Ford et al. 1994, Harms et al. 1994).The disk shows tantalizing evidence for spiral structure and a possibleconnection to large scale, wrapped filaments. Sparks, Ford, and Kinney(1993) used observations of dust absorption in the filaments andblueshifted velocities with respect to M87 to conclude that thefilaments are an outflow from the nucleus. If the wrapped filamentsare in fact an outflow, we are witnessing the solution to anoutstanding problem in astrophysics, that of removing angular momentumfrom a disk to allow the gas to flow onto the central massive black hole.We propose to use 6 orbits to take deep, half-pixel stepped,Halpha+[Nii] on-band images to study the morphology in the disk andfilaments. The images will be one magnitude deeper than previousimages and will reach the 0.06'' diffraction limit of the telescopeat Halpha. Our goals are to use the deep, high resolution images to:1) Investigate and understand the apparent connection between thefilaments and the disk.2) Delineate the apparent spiral structure in the disk.3) Confirm the presence of faint Halpha+[Nii] emission associated withthe jet, which could be gas which has been entrained by the jet.

Ford, Holland

1995-07-01

334

Improvement of low temperature estimation for MODIS thermal emissive bands by adjusting calibration offset and nonlinear terms  

Microsoft Academic Search

MODIS is a major instrument for the NASA EOS Terra and Aqua missions, launched in December 1999 and May 2002 respectively. MODIS has 16 thermal emissive bands and they are calibrated using an onboard blackbody (BB) based on a nonlinear second order relationship. While the gains of the MODIS thermal bands are calibrated on a scan-by-scan basis, the offset and

A. Wu; X. Xiong; B. Wenny; C. Moeller; N. Chen; K. Chiang

2007-01-01

335

Narrow-band imaging does not improve detection of colorectal polyps when compared to conventional colonoscopy: a randomized controlled trial and meta-analysis of published studies  

PubMed Central

Background A colonoscopy may frequently miss polyps and cancers. A number of techniques have emerged to improve visualization and to reduce the rate of adenoma miss. Methods We conducted a randomized controlled trial (RCT) in two clinics of the Gastrointestinal Department of the Sanitas University Foundation in Bogota, Colombia. Eligible adult patients presenting for screening or diagnostic elective colonoscopy were randomlsy allocated to undergo conventional colonoscopy or narrow-band imaging (NBI) during instrument withdrawal by three experienced endoscopists. For the systematic review, studies were identified from the Cochrane Library, PUBMED and LILACS and assessed using the Cochrane risk of bias tool. Results We enrolled a total of 482 patients (62.5% female), with a mean age of 58.33 years (SD 12.91); 241 into the intervention (NBI) colonoscopy and 241 into the conventional colonoscopy group. Most patients presented for diagnostic colonoscopy (75.3%). The overall rate of polyp detection was significantly higher in the conventional group compared to the NBI group (RR 0.75, 95%CI 0.60 to 0.96). However, no significant differences were found in the mean number of polyps (MD -0.1; 95%CI -0.25 to 0.05), and the mean number of adenomas (MD 0.04 95%CI -0.09 to 0.17). Meta-analysis of studies (regardless of indication) did not find any significant differences in the mean number of polyps (5 RCT, 2479 participants; WMD -0.07 95% CI -0.21 to 0.07; I2 68%), the mean number of adenomas (8 RCT, 3517 participants; WMD -0.08 95% CI -0.17; 0.01 to I2 62%) and the rate of patients with at least one adenoma (8 RCT, 3512 participants, RR 0.96 95% CI 0.88 to 1,04;I2 0%). Conclusion NBI does not improve detection of colorectal polyps when compared to conventional colonoscopy (Australian New Zealand Clinical Trials Registry ACTRN12610000456055). PMID:21943365

2011-01-01

336

Adjuvant Narrow Band UVB Improves the Efficacy of Oral Azithromycin for the Treatment of Moderate to Severe Inflammatory Facial Acne Vulgaris  

PubMed Central

Background: Acne vulgaris (AV) is a common inflammatory disease of the pilosebaceous unit. A variety of treatment modalities are available for the treatment of AV. Among the available options, oral azithromycin is popularly prescribed for its proven anti-inflammatory effects. Narrow band UVB (NBUVB) also has a potent anti-inflammatory action. Concomitant use of both modalities may result in a synergistic therapeutic response; however, the combined efficacy has not yet been evaluated for the treatment of inflammatory AV. Objective: The aim of this study was to compare the efficacy of oral azithromycin plus NBUVB (peak 311 nm) to oral azithromycin alone for the treatment of moderate to severe inflammatory AV. Materials and Methods: A randomized, open-label, clinical trial was conducted over 4 weeks. Subjects were randomized into two groups. Group 1 received 500 mg of oral azithromycin three times per week. Group 2 received 500 mg of oral azithromycin plus NBUVB three and two times per week, respectively. Concomitant topical or oral AV treatments were not permitted during the treatment period. Response to treatment was measured by photographic records at the primary endpoint (2 weeks) and at the end of treatment. Results: One hundred and four subjects were enrolled in the trial; 94 subjects completed the treatment period of the study. Group 2 demonstrated significant clinical improvement of the inflammatory papular lesions (88.55%) compared with group 1 (70.34%) at the end of treatment (P = 0.002). The clinical response of pustular (P = 0.562), nodular (P = 0.711) and cystic (P = 0.682) lesions did not significantly differ between the two treatment groups. Interestingly, response to treatment in group 2 had a significant anatomical predilection for the forehead (P = 0.023). There was no side-effect except erythema, which subsided within 1-2 days. Conclusion: NBUVB plus oral azithromycin is more effective than oral azithromycin alone for treating papular lesions of inflammatory AV. NBUVB is certainly a viable adjunct in acne therapy.

Rassai, Sima; Rafeie, Esmaeil; Ramirez-Fort, Marigdalia K; Feily, Amir

2014-01-01

337

Monitoring water stress and fruit quality in an orange orchard under regulated deficit irrigation using narrow-band structural and physiological remote sensing indices  

NASA Astrophysics Data System (ADS)

This paper deals with the monitoring of water status and the assessment of the effect of stress on citrus fruit quality using structural and physiological remote sensing indices. Four flights were conducted over a citrus orchard in 2009 using an unmanned aerial vehicle (UAV) carrying a multispectral camera with six narrow spectral bands in the visible and near infrared. Physiological indices such as the Photochemical Reflectance Index (PRI570), a new structurally robust PRI formulation that uses the 515 nm as the reference band (PRI515), and a chlorophyll ratio (R700/R670) were compared against the Normalized Difference Vegetation Index (NDVI), Renormalized Difference Vegetation Index (RDVI) and Modified Triangular Vegetation Index (MTVI) canopy structural indices for their performance in tracking water status and the effects of sustained water stress on fruit quality at harvest. The irrigation setup in the commercial orchard was compared against a treatment scheduled to satisfy full requirements (based on estimated crop evapotranspiration) using two regulated deficit irrigation (RDI) strategies. The water status of the trees throughout the experiment was monitored with frequent field measurements of stem water potential (?x), while titratable acidity (TA) and total soluble solids (TSS) were measured at harvest on selected trees from each irrigation treatment. The high spatial resolution of the multispectral imagery (30 cm pixel size) enabled identification of pure tree crown components, extracting the tree reflectance from shaded, sunlit and aggregated pixels. The physiological and structural indices were then calculated from each tree at the following levels: (i) pure sunlit tree crown, (ii) entire crown, aggregating the within-crown shadows, and (iii) simulating a lower resolution pixel, including tree crown, sunlit and shaded soil pixels. The resulting analysis demonstrated that both PRI formulations were able to track water status, except when water stress altered canopy structure. In such cases, PRI570 was more affected than PRI515 by the structural changes caused by sustained water stress throughout the season. Both PRI formulations were proven to serve as pre-visual water stress indicators linked to fruit quality TSS and TA parameters (r2 = 0.69 for PRI515 vs TSS; r2 = 0.58 vs TA). In contrast, the chlorophyll (R700/R670) and structural indices (NDVI, RDVI, MTVI) showed poor relationships with fruit quality and water status levels (r2 = 0.04 for NDVI vs TSS; r2 = 0.19 vs TA). The two PRI formulations showed strong relationships with the field-measured fruit quality parameters in September, the beginning of stage III, which appeared to be the period most sensitive to water stress and the most critical for assessing fruit quality in citrus. Both PRI515 and PRI570 showed similar performance for the two scales assessed (sunlit crown and entire crown), demonstrating that within-crown component separation is not needed in citrus tree crowns where the shaded vegetation component is small. However, the simulation conducted through spatial resampling on tree + soil aggregated pixels revealed that the physiological indices were highly affected by soil reflectance and between-tree shadows, showing that for TSS vs PRI515 the relationship dropped from r2 = 0.69 to r2 = 0.38 when aggregating soil + crown components. This work confirms a previous study that demonstrated the link between PRI570, water stress, and fruit quality, while also making progress in assessing the new PRI formulation (PRI515), the within-crown shadow effects on the physiological indices, and the need for high resolution imagery to target individual tree crowns for the purpose of evaluating the effects of water stress on fruit quality in citrus.

Stagakis, S.; González-Dugo, V.; Cid, P.; Guillén-Climent, M. L.; Zarco-Tejada, P. J.

2012-07-01

338

High resolution extraction of fiber propagation parameters for accurate modeling of slow light systems based on narrow band optical parametric amplification  

Microsoft Academic Search

The spatial distributions of fiber propagation parameters are estimated with a high spatial resolution using measured ASE spectra of narrow parametric gain. This allows accurate modeling of slow light propagation of high bit rate data.

E. Shumakher; A. Willinger; R. Blit; D. Dahan; G. Eisenstein

2007-01-01

339

Plasmonic nanoantennas for broad-band enhancement of two-photon emission from semiconductors.  

PubMed

We demonstrate experimentally and theoretically a broad-band enhancement of the spontaneous two-photon emission from AlGaAs at room temperature by plasmonic nanoantenna arrays fabricated on the semiconductor surface. Plasmonic structures with inherently low quality factors but very small effective volumes are shown to be optimal. A 20-fold enhancement was achieved for the entire antenna array, corresponding to an enhancement of nearly 3 orders of magnitude for charge carriers emitting at the near field of a plasmonic antenna. PMID:20397660

Nevet, Amir; Berkovitch, Nikolai; Hayat, Alex; Ginzburg, Pavel; Ginzach, Shai; Sorias, Ofir; Orenstein, Meir

2010-05-12

340

Quantum simulation of the yellow emission band of CsXe  

NASA Technical Reports Server (NTRS)

Quantum spectral simulations of the yellow excimer emission band of CsXe are presented. Synthetic spectra as a function of wave number are calculated for the 2 Sigma 1/2 + (7s) - 2 Sigma 1/2 + (6s) transition by the use of the equation of Tellinghuisen et al. (1976) with a theoretical potential for the ground state and a Morse potential curve with an electron frequency of 32/cm for the excited state. Results based on emission studies at 450 K and 200 and 800 torr, are found to be consistent with absorption studies. The undulatory structure observed in the spectrum is attributed not to the vibrational spacing in the excited state, but rather to a characteristic reflection structure associated with nearly parallel upper and lower potential curves.

Tellinghuisen, J.; Exton, R. J.

1980-01-01

341

Band-limited Green's Functions for Quantitative Evaluation of Acoustic Emission Using the Finite Element Method  

NASA Technical Reports Server (NTRS)

A method of numerically estimating dynamic Green's functions using the finite element method is proposed. These Green's functions are accurate in a limited frequency range dependent on the mesh size used to generate them. This range can often match or exceed the frequency sensitivity of the traditional acoustic emission sensors. An algorithm is also developed to characterize an acoustic emission source by obtaining information about its strength and temporal dependence. This information can then be used to reproduce the source in a finite element model for further analysis. Numerical examples are presented that demonstrate the ability of the band-limited Green's functions approach to determine the moment tensor coefficients of several reference signals to within seven percent, as well as accurately reproduce the source-time function.

Leser, William P.; Yuan, Fuh-Gwo; Leser, William P.

2013-01-01

342

Acoustic emissions and porosity reduction during growth of discrete compaction bands in porous sandstone  

NASA Astrophysics Data System (ADS)

Recent field and laboratory studies have documented the occurrence of strain localisation in porous sandstones. The localised failure mode can be in shear or compaction, in the form of conjugate shear or compaction bands oriented at relatively high angles to the maximum compression direction. Compaction bands in particular have drawn a lot of interest because these localized structures could potentially act as barriers for fluid flow in reservoirs and aquifers. To elucidate the complexity of the occurrence and growth of discrete compaction bands in porous sandstones, we performed a series of triaxial deformation experiments on Bentheim sandstone. The experiments were done on saturated samples under drained condition at different confining and pore pressures. During the experiments, confining pressure and pore pressure were controlled to within about 1% with the help of two external servo-controlled pressure intensifiers. Acoustic emission (AE) activity was monitored continuously during the experiments by up to 8 piezoelectric transducers attached to the sample. For each transducer, several characteristics of the AE signals, such as amplitude and energy were recorded continuously. Our results show that the occurrence and growth of compaction bands was followed by small stress drops in the mechanical data and very large AE outputs. From the AE data, we calculated the evolution of the seismic b-value associated with strain localisation in the compactive regime. During the compaction process, our fully servo-controlled experimental set-up enabled us also to follow the step-by-step decrease in porosity in the samples associated with the sequential development of discrete compaction bands.

Baud, P.; Meredith, P.; Boon, S.

2003-04-01

343

Model of the optical emission of a driven semiconductor quantum dot: phonon-enhanced coherent scattering and off-resonant sideband narrowing  

E-print Network

We study the crucial role played by the solid-state environment in determining the photon emission characteristics of a driven quantum dot. For resonant driving, we predict a phonon-enhancement of the coherently emitted radiation field with increasing driving strength, in stark contrast to the conventional expectation of a rapidly decreasing fraction of coherent emission with stronger driving. This surprising behaviour results from thermalisation of the dot with respect to the phonon bath, and leads to a nonstandard regime of resonance fluorescence in which significant coherent scattering and the Mollow triplet coexist. Off-resonance, we show that despite the phonon influence, narrowing of dot spectral sideband widths can occur in certain regimes, consistent with an experimental trend.

Dara P. S. McCutcheon; Ahsan Nazir

2013-05-30

344

Probing Unification With Chandra HETGS and XMM-Newton EPIC And RGS Spectroscopy of the Narrow Emission Line Galaxy NGC 2110  

E-print Network

We present results from Chandra HETGS (250 ks over two epochs) and XMM-Newton EPIC and RGS (60 ks) observations of NGC 2110, which has been historically classified as a Narrow Emission Line Galaxy galaxy. Our results support the interpretation that the source is a Seyfert 2 viewed through a patchy absorber. The nuclear X-ray spectrum of the source is best described by a power law of photon index $\\Gamma$ ~1.7, modified by absorption from multiple layers of neutral material at a large distance from the central supermassive black hole. We report the strong detections of Fe K$\\alpha$ and Si K$\\alpha$ lines, which are marginally resolved with the Chandra HETGS, and we constrain the emission radius of the fluorescing material to >1 pc. There is some evidence for modest additional broadening at the base of the narrow Fe K$\\alpha$ core with a velocity ~4500 km s$^{-1}$. We find tentative evidence for ionized emission (O VIII Ly $\\alpha$, an O VIII RRC feature, and possibly a Ne IX forbidden line) in the Chandra MEG and XMM-Newton RGS spectra, which could be associated with the known extended X-ray emission that lies ~160 pc from the nucleus. We suggest that the $10^{23}$ cm$^{-2}$ partially covering absorber originates in broad-line region clouds in the vicinity of the AGN, and that the $3\\times10^{22}$ cm$^{-2}$ coverer is likely to have a more distant origin and have a flattened geometry in order to allow the small-scale radio jet to escape.

Daniel A. Evans; Julia C. Lee; T. Jane Turner; Kimberly A. Weaver; Herman L. Marshall

2007-08-30

345

Ruling out unresolved binaries in five transitional disks. VLT/NACO deep 2.12 and 1.75 ?m narrow-band imaging  

NASA Astrophysics Data System (ADS)

Context. The presence of unresolved binaries on sub-arsecond scales could explain the existence of optically thin inner holes or gaps in circumstellar disks, which are commonly referred to as "transitional" or "cold" disks, and it is the first scenario to check before making any other assumptions. Aims: We aim at detecting the presence of companions inside the inner hole/gap region of a sample of five well known transitional disks using spatially-resolved imaging in the near-IR with the VLT/NACO/S13 camera, which probes projected distances from the primary of typically 0.1 to 7 arcsec. The sample includes the stars DoAr 21, HD 135344B (SAO 206462), HR 4796A, T Cha, and TW Hya, spanning ages of less than 1 to 10 Myr, spectral types of A0 to K7, and hole/gap outer radii of 4 to 100 AU. Methods: In order to enhance the contrast and to avoid saturation at the core of the point-spread function (PSF), we use narrow-band filters at 1.75 and 2.12 ?m. The "locally optimized combination of images" (LOCI) algorithm is applied for an optimal speckle noise removal and PSF subtraction, providing an increase of 0.5-1.5 mag in contrast over the classic method. Results: With the proviso that we could have missed companions owing to unfavorable projections, the VLT/NACO observations rule out the presence of unresolved companions down to an inner radius of about 0.1 arcsec from the primary in all five transitional disks and with a detection limit of 2 to 5 mag in contrast. In the disk outer regions the detection limits typically reach 8 to 9 mag in contrast and 4.7 mag for T Cha. Hence, the NACO images resolve part of the inner hole/gap region of all disks with the exception of TW Hya, for which the inner hole is only 4 AU. The 5? sensitivity profiles, together with a selected evolutionary model, allow to discard stellar companions within the inner hole/gap region of T Cha, and down to the substellar regime for HD 135344B and HR 4796A. DoAr 21 is the only object from the sample of five disks for which the NACO images are sensitive enough for a detection of objects less massive than ~13 MJup that is, potential giant planets or low-mass brown dwarfs at radii larger than ~76 AU (0.63 arcsec). Conclusions: These new VLT/NACO observations further constrain the origin of the inner opacity cavities to be owing to closer or lower-mass companions or other mechanisms such as giant planet formation, efficient grain growth, and photoevaporation (for DoAr 21 and HR 4796A).

Vicente, S.; Merín, B.; Hartung, M.; Bouy, H.; Huélamo, N.; Artigau, E.; Augereau, J.-C.; van Dishoeck, E.; Olofsson, J.; Oliveira, I.; Prusti, T.

2011-09-01

346

The emission spectrum of helium hydride. II. Bands near 5500 and 6400 A  

SciTech Connect

The emission bands of helium hydride near 5500 and 6400 A were analyzed for {sup 4}HeH, {sup 3}HeD, and {sup 4}HeD. They are assigned to the emission of the coupled states {ital D} {sup 2}{Sigma}{sup +}, (3{ital d}, L=2) and (for the deuterides) {ital C} {sup 2}{Sigma}{sup +}, {ital v}=3 to the {ital A} {sup 2}{Sigma}{sup +} (5500 A) and {ital B} {sup 2}{Pi} (6400 A) states. The 3{ital d}, L=2 state is treated as pure Hund's case (d). The coupling of the electronic states is homogeneous and described by constant matrix elements. Only in the case of {sup 4}HeH, strong predissociation of the {ital D} state was observed for {ital N}{prime}{ge}3. The emission spectra were observed after neutralization of a fast (15 keV) mass-selected HeH{sup +} beam in potassium vapor.

Ketterle, W. (Max-Planck-Institut fuer Quantenoptik, D-8046 Garching bei Muenchen (Federal Republic of Germany))

1990-09-15

347

Performance of MODIS Thermal Emissive Bands On-orbit Calibration Algorithms  

NASA Technical Reports Server (NTRS)

Two nearly identical copies of the Moderate Resolution Imaging Spectroradiometer (MODIS) are currently operated on-board the Terra and Aqua spacecrafts, launched in December 1999 and May 2002, respectively. Together, they have produced an unprecedented amount of science data products, which are widely used for the studies of changes in the Earth's system of land, oceans, and atmosphere. MODIS is a cross-track scanning radiometer, which uses a two-sided scan mirror and collects data continuously over a wide scan angle range (+/-55 degree relative to the instrument nadir) each scan of 1.47 seconds. It has 36 spectral bands with wavelengths ranging from visible (VIS) to long-wave infrared (LWIR). MODIS bands 1-19 and 26 are the reflective solar bands (RSB) and bands 20-25 and 27-36 are the thermal emissive bands (TEB). MODIS was developed and designed with improvements made over its heritage sensors (such as AVHRR and Landsat) and, in particular, with more stringent calibration requirements. Because of this, MODIS was built with a set of state-of-art on-board calibrators (OBC), which include a solar diffuser (SD), a solar diffuser stability monitor (SDSM), a blackbody (BB), a spectroradiometric calibration assembly (SRCA), and a space view (SV) port. With the exception of view angle differences, MODIS OBC measurements and the Earth View (EV) observations are made via the same optical path. MODIS TEB have a total of 160 individual TEB detectors (10 per band), which are located on two cold focal plane assemblies (CFPA). For nominal on-orbit operation, the CFPA temperature is controlled at 83K via a passive radiative cooler. For the TEB, the calibration requirements at specified typical scene radiances are less than or equal to 1% with an exception for the fire detection (low gain) band. MODIS TEB on-orbit calibration is performed on a scan-by-scan basis using a quadratic calibration algorithm, and data collected from sensor responses to the onboard BB and SV. The BB serves as the thermal calibration source and the SV provides measurements for the sensor's background and offsets. MODIS on-board BB is a v-grooved plate with its temperature measured using 12 platinum resistive thermistors (PRT) uniformly embedded in the BB substrate. All the BB thermistors were characterized pre-launch with reference to the NIST temperature standards. Unlike typical BB operations in many heritage sensors, which have no temperature control capability, the MODIS on-board BB can be operated at any temperatures between instrument ambient (about 270K) and 315K and can also be varied continuously within this range. This feature has significantly enhanced the MODIS' capability of tracking and updating the TEB nonlinear calibration coefficients over its entire mission. Following a brief description of MODIS TEB on-orbit calibration methodologies and its onboard BB operational activities, this paper provides a comprehensive performance assessment of MODIS TEB quadratic calibration algorithm. It examines the scan-by-scan, orbit-by-orbit, daily, and seasonal variations of detector responses and associated impact due changes in the CFPA and instrument temperatures. Specifically, this paper will analyze the contribution by each individual thermal emissive source term (BB, scan cavity, and scan mirror), the impact on the Level 1 B data product quality due to pre-launch and on-orbit calibration uncertainties. A comparison of Terra and Aqua TEB on-orbit performance, lessons learned, and suggestions for future improvements will also be made.

Xiong, Xiaoxiong; Chang, T.

2009-01-01

348

Structural phase transition, narrow band gap, and room-temperature ferromagnetism in [KNbO3]1-x[BaNi1/2Nb1/2O3-?]x ferroelectrics  

NASA Astrophysics Data System (ADS)

Structural phase transition, narrow band gap (Eg), and room-temperature ferromagnetism (RTFM) have been observed in the [KNbO3]1-x[BaNi1/2Nb1/2O3-?]x (KBNNO) ceramics. All the samples have single phase perovskite structure, but exhibit a gradual transition behaviour from the orthorhombic to a cubic structure with the increase of x. Raman spectroscopy analysis not only corroborates this doping-induced change in normal structure but also shows the local crystal symmetry for x ? 0.1 compositions to deviate from the idealized cubic perovskite structure. A possible mechanism for the observed specific changes in lattice structure is discussed. Moreover, it is noted that KBNNO with compositions x = 0.1-0.3 have quite narrow Eg of below 1.5 eV, much smaller than the 3.2 eV band gap of parent KNbO3 (KNO), which is due to the increasing Ni 3d electronic states within the gap of KNO. Furthermore, the KBNNO materials present RTFM near a tetragonal to cubic phase boundary. With increasing x from 0 to 0.3, the magnetism of the samples develops from diamagnetism to ferromagnetism and paramagnetism, originating from the ferromagnetic-antiferromagnetic competition. These results are helpful in the deeper understanding of phase transitions, band gap tunability, and magnetism variations in perovskite oxides and show the potential role, such materials can play, in perovskite solar cells and multiferroic applications.

Zhou, Wenliang; Deng, Hongmei; Yang, Pingxiong; Chu, Junhao

2014-09-01

349

Quantum cascade lasers: ultrahigh-speed operation, optical wireless communication, narrow linewidth, and far-infrared emission  

Microsoft Academic Search

Abstract—Following an introduction to the history of the inven- tion of the quantum,cascade (QC) laser and of the band-structure engineering advances that have led to laser action over most of the mid-infrared (IR) and part of the far-IR spectrum, the paper provides a comprehensive review of recent developments that will likely enable important advances in areas such as optical commu-

F. Capasso; R. Paiella; R. Martini; R. Colombelli; C. Gmachl; T. L. Myers; M. S. Taubman; R. M. Williams; C. G. Bethea; K. Unterrainer; H. Y. Hwang; D. L. Sivco; A. Y. Cho; A. M. Sergent; H. C. Liu; E. A. Whittaker

2002-01-01

350

Spatial distribution and variation of narrow L-shell bands in the plasmasphere supporting field-aligned propagating modes as observed by the RPI/IMAGE satellite  

NASA Astrophysics Data System (ADS)

Field-aligned propagating (FAP) modes have been a regular characteristic of the RPI/IMAGE plasmagrams from the beginning of the experiment. LF/MF (in the range of 3 kHz to 3 MHz) transmitted radio signals from the satellite propagate in the magnetic meridian plane along the magnetic field line passing through the satellite position to both the northern and southern hemispheres where they reflect at a level that depends on the sounding frequency. This analysis has shown that these hemispherical reflections occur on about 20% of the plasmagrams while the IMAGE satellite is between L = 2.5 and L = 4.5. Occurrences of these FAP plasmagrams were consistently organized into two L-shell bands. The first band was found at L = 3.2+/- 0.2 moving in and out slowly over a period of a few days. This band, with a width of DL >> 0.2, is always present. The second observed band also supports hemispherical propagation and was found at higher L-shells, ranging from L = 3.5 under quiet magnetic conditions, moving to L = 4.0 as the level of magnetic activity increases. During high magnetic activity conditions this outer band disappears. When RPI/IMAGE passed through the inner band the probability of the appearance of FAP modes was 98% while for the outer band this percentage drops to 91%. Analyzing 5 months of data using an RPI sounding program that makes a new plasmagram every 3 minutes as the satellite traverses the plasmasphere has lead to a comprehensive description of these bands that can be mapped down to the mid-latitude trough region. Comparison is made between the plasmaspause location and the tail region as determined using other sensors with respect to the position of the two bands under changing magnetic conditions.

Sales, G.; Reinisch, B. W.; Song, P.; Huang, X.; Galkin, I.; Gallagher, D. L.

2002-12-01

351

Impact of Conifer Forest Litter on Microwave Emission at L-Band  

NASA Technical Reports Server (NTRS)

This study reports on the utilization of microwave modeling, together with ground truth, and L-band (1.4-GHz) brightness temperatures to investigate the passive microwave characteristics of a conifer forest floor. The microwave data were acquired over a natural Virginia Pine forest in Maryland by a ground-based microwave active/passive instrument system in 2008/2009. Ground measurements of the tree biophysical parameters and forest floor characteristics were obtained during the field campaign. The test site consisted of medium-sized evergreen conifers with an average height of 12 m and average diameters at breast height of 12.6 cm. The site is a typical pine forest site in that there is a surface layer of loose debris/needles and an organic transition layer above the mineral soil. In an effort to characterize and model the impact of the surface litter layer, an experiment was conducted on a day with wet soil conditions, which involved removal of the surface litter layer from one half of the test site while keeping the other half undisturbed. The observations showed detectable decrease in emissivity for both polarizations after the surface litter layer was removed. A first-order radiative transfer model of the forest stands including the multilayer nature of the forest floor in conjunction with the ground truth data are used to compute forest emission. The model calculations reproduced the major features of the experimental data over the entire duration, which included the effects of surface litter and ground moisture content on overall emission. Both theory and experimental results confirm that the litter layer increases the observed canopy brightness temperature and obscure the soil emission.

Kurum, Mehmet; O'Neill, Peggy E.; Lang, Roger H.; Cosh, Michael H.; Joseph, Alicia T.; Jackson, Thomas J.

2011-01-01

352

Incomplete relaxation and plasmon formation in the K emission band of copper  

NASA Astrophysics Data System (ADS)

A method of calculating the effect of self-absorption in X-ray emission spectra and which is suitable for non-adiabatic excitation processes is presented. The Fermi-level EF and the "true" profile of the electron-excited (20-40keV) Cu K? 2,5 band are determined. A deviation from the calvulated one-electron spectrum in the energy interval [-12 eV, -7 eV] below EF is interpreted as a result of plasmon formation and Auger broadening. A pronounced disagreement is found also in the range [-1 eV, + 10eV]. Above EF, a part of the intensity may be due to incomplete electron relaxation.

Bremer, J.

1983-09-01

353

The GROUSE project III: Ks-band observations of the thermal emission from WASP-33b  

E-print Network

In recent years, day-side emission from about a dozen hot Jupiters has been detected through ground-based secondary eclipse observations in the near-infrared. These near-infrared observations are vital for determining the energy budgets of hot Jupiters, since they probe the planet's spectral energy distribution near its peak. The aim of this work is to measure the Ks-band secondary eclipse depth of WASP-33b, the first planet discovered to transit an A-type star. This planet receives the highest level of irradiation of all transiting planets discovered to date. Furthermore, its host-star shows pulsations and is classified as a low-amplitude delta-Scuti. As part of our GROUnd-based Secondary Eclipse (GROUSE) project we have obtained observations of two separate secondary eclipses of WASP-33b in the Ks-band using the LIRIS instrument on the William Herschel Telescope (WHT). The telescope was significantly defocused to avoid saturation of the detector for this bright star (K~7.5). To increase the stability and th...

de Mooij, E J W; de Kok, R J; Snellen, I A G; Kenworthy, M A; Karjalainen, R; 10.1051/0004-6361/201219434

2013-01-01

354

Aqua MODIS Thermal Emissive Band On-Orbit Calibration, Characterization, and Performance  

NASA Technical Reports Server (NTRS)

The NASA's Earth Observing System Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) has continued to operate with satisfactory performance since its launch in May 2002, exceeding its nominal six-year design lifetime. Its continuous Earth observations have been used to generate many science data products for studies of the Earth's, system. MODIS has 36 spectral bands; 20 reflective solar bands and 16 thermal emissive bands (TEBs). All TEB observations are made at 1-km nadir spatial resolution with spectral wavelengths from 3.7 to 14.4 pm. Primary applications of MODIS TEB 'include surface, cloud, and atmospheric temperatures, water vapor, and cloud top altitude. MODIS TEB on-orbit calibration uses a quadratic algorithm with its calibration coefficients derived using an onboard blackbody (BB). This paper will present Aqua MODIS TEB on-orbit calibration, characterization, and performance over its six-year mission. Examples of instrument thermal behavior, BB temperature stability, detector short-term stability, and changes in long-term response (or system gain) will be presented. Comparisons will also be made with Terra MODIS, launched in December 1999. On-orbit results show that Aqua MODIS and its focal plane temperatures have behaved normally. BB temperature has remained extremely stable with typical scan -to-scan variations of less than +/-0.15 mK. Most TEB detectors continue to exceed their specified signal-to-noise ratio requirements, exhibiting excellent short-term stability and calibration accuracy. Excluding a few noisy detectors, either identified prelaunch or occurring postlaunch, on-orbit changes in TEB responses have been less than 0.5% on an annual basis. By comparison; the overall Aqua TEB performance has been better than that of Terra MODIS,

Xiong, Xiaoxiong; Wenny, Brian N.; Wu, Aisheng; Barnes, William L.; Salomonson, Vincent V.

2009-01-01

355

Intrinsic single-band upconversion emission in colloidal Yb/Er(Tm):Na3Zr(Hf)F7 nanocrystals.  

PubMed

Novel Yb/Er(Tm):Na(3)MF(7) (M = Zr, Hf) nanocrystals with intrinsic single-band upconversion emission, in contrast to the routine lanthanide-doped fluoride nanocrystals which show typical multi-band upconversion emissions, are reported for the first time. Specifically, the red upconversion intensity of the Yb/Er:Na(3)ZrF(7) nanocrystals is about 5 times as high as that of the hexagonal Yb/Er:NaYF(4) ones with a similar crystal size. PMID:23010848

Chen, Daqin; Lei, Lei; Zhang, Rui; Yang, Anping; Xu, Ju; Wang, Yuansheng

2012-11-01

356

Emission Cross Sections of the Lyman-Birge-Hopfield Band System in Molecular Nitrogen Induced by Electron Impact Excitation  

Microsoft Academic Search

Emissions from the Lyman-Birge-Hopfield (LBH) band system in N2 (a 1Pig --> X 1sigmag+) are the most prominent molecular features below 180 nm in the Earth's atmosphere [Kanik et al., Phys. Chem. Earth (C), 25, 573, 2000]. LBH emissions continue to be of interest as a sensitive test of N2 density distributions and photoelectron flux in the dayglow and secondary

C. P. Malone; P. V. Johnson; J. M. Ajello; I. Kanik

2005-01-01

357

FERMI/LARGE AREA TELESCOPE DISCOVERY OF GAMMA-RAY EMISSION FROM A RELATIVISTIC JET IN THE NARROW-LINE QUASAR PMN J0948+0022  

SciTech Connect

We report the discovery by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope of high-energy {gamma}-ray emission from the peculiar quasar PMN J0948+0022 (z = 0.5846). The optical spectrum of this object exhibits rather narrow H{beta} (FWHM(H{beta}) {approx}1500 km s{sup -1}), weak forbidden lines, and is therefore classified as a narrow-line type I quasar. This class of objects is thought to have relatively small black hole mass and to accrete at a high Eddington ratio. The radio loudness and variability of the compact radio core indicate the presence of a relativistic jet. Quasi-simultaneous radio/optical/X-ray and {gamma}-ray observations are presented. Both radio and {gamma}-ray emissions (observed over five months) are strongly variable. The simultaneous optical and X-ray data from Swift show a blue continuum attributed to the accretion disk and a hard X-ray spectrum attributed to the jet. The resulting broadband spectral energy distribution (SED) and, in particular, the {gamma}-ray spectrum measured by Fermi are similar to those of more powerful Flat-Spectrum Radio Quasars (FSRQs). A comparison of the radio and {gamma}-ray characteristics of PMN J0948+0022 with the other blazars detected by LAT shows that this source has a relatively low radio and {gamma}-ray power with respect to other FSRQs. The physical parameters obtained from modeling the SED also fall at the low power end of the FSRQ parameter region discussed in Celotti and Ghisellini. We suggest that the similarity of the SED of PMN J0948+0022 to that of more massive and more powerful quasars can be understood in a scenario in which the SED properties depend on the Eddington ratio rather than on the absolute power.

Abdo, A. A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Ackermann, M.; Ajello, M.; Bechtol, K.; Bloom, E. D.; Borgland, A. W. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Axelsson, M.; Battelino, M. [Oskar Klein Centre for Cosmo Particle Physics, AlbaNova, SE-106 91 Stockholm (Sweden); Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, F-91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Baughman, B. M. [Department of Physics, Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Brigida, M.; Caliandro, G. A. [Dipartimento di Fisica 'M. Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy); Bruel, P. [Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France)], E-mail: luigi.foschini@brera.inaf.it (and others)

2009-07-10

358

Use of IRI to Model the Effect of Ionosphere Emission on Earth Remote Sensing at L-Band  

NASA Technical Reports Server (NTRS)

Microwave remote sensing in the window at 1.413 GHz (L-band) set aside for passive use only is important for monitoring sea surface salinity and soil moisture. These parameters are important for understanding ocean dynamics and energy exchange between the surface and atmosphere, and both NASA and ESA plan to launch satellite sensors to monitor these parameters at L-band (Aquarius, Hydros and SMOS). The ionosphere is an important source of error for passive remote sensing at this frequency. In addition to Faraday rotation, emission from the ionosphere is also a potential source of error at L-band. As an aid for correcting for emission, a regression model is presented that relates ionosphere emission to the integrated electron density (TEC). The goal is to use TEC from sources such as TOPEX, JASON or GPS to obtain estimates of emission over the oceans where the electron density profiles needed to compute emission are not available. In addition, data will also be presented to evaluate the use of the IRI for computing emission over the ocean.

Abraham, Saji; LeVine, David M.

2004-01-01

359

The Ground-based H-, K-, and L-band Absolute Emission Spectra of HD 209458b  

NASA Astrophysics Data System (ADS)

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 CH4 ?3 fluorescence. We do not detect a similar bright 3.3 ?m feature to ~3?, 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 1? 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.

Zellem, Robert T.; Griffith, Caitlin A.; Deroo, Pieter; Swain, Mark R.; Waldmann, Ingo P.

2014-11-01

360

2D XANES-XEOL mapping: observation of enhanced band gap emission from ZnO nanowire arrays  

NASA Astrophysics Data System (ADS)

Using 2D XANES-XEOL spectroscopy, it is found that the band gap emission of ZnO nanowire arrays is substantially enhanced i.e. that the intensity ratio between the band gap and defect emissions increases by more than an order of magnitude when the excitation energy is scanned across the O K-edge. Possible mechanisms are discussed.Using 2D XANES-XEOL spectroscopy, it is found that the band gap emission of ZnO nanowire arrays is substantially enhanced i.e. that the intensity ratio between the band gap and defect emissions increases by more than an order of magnitude when the excitation energy is scanned across the O K-edge. Possible mechanisms are discussed. Electronic supplementary information (ESI) available: XEOL spectra with different excitation energies. X-ray attenuation length vs. photon energy. Details of surface defects in ZnO NWs. The second O K-edge and Zn L-edge 2D XANES-XEOL maps. Comparison of the first and second TEY at O K-edge and Zn L-edge scans, respectively. Raman spectra of the ZnO NWs with different IBGE/IDE ratios. See DOI: 10.1039/c4nr01049c

Wang, Zhiqiang; Guo, Xiaoxuan; Sham, Tsun-Kong

2014-05-01

361

Observation of nitric oxide rovibrational band head emissions in the quiescent airglow during the CIRRIS-1A space shuttle experiment  

Microsoft Academic Search

Band head emissions from highly rotationally excited NO (v, J) (J approx. equals 90) have been observed in the quiescent atmosphere at tangent heights between approximately 115 and 190 km for both sunlit and nighttime conditions. The data were obtained by the Cryogenic Infrared Radiance Instrumentation for Shuttle (CIRRIS-1A) interferometer which was operated on-board the space shuttle between 28 and

D. R. Smith; M. Ahmadjian

1993-01-01

362

Alterations in Cochlear Function after Exposure to Short Term Broad Band Noise Assessed by Otoacoustic Emissions  

PubMed Central

Background: Sudden or chronic exposure to sound alters the functioning of cochlea. This results in temporary or permanent alteration of functioning of cochlear cells. Alteration of functioning of outer hair cells (OHC) of cochlea following exposure to noise can be assessed by measurement of transient otoacoustic emissions (TEOAE). Such a measurement is of great clinical importance in early detection of the damage to the OHC. Aim: In this study we aim to study effect of noise on outer hair cell function by studying the changes in TEOAE’s amplitude following exposure to short term broad band noise in healthy volunteers. Materials and Methods: Twenty volunteers’ ten males and ten females participated in the study. They underwent pure tone and impedance audiometry to rule out ear pathology. Then pre-exposure TEOAE’s were recorded. After that they were exposed to broad band noise for two minutes. After gap of five minutes again TEOAE’s were recorded. Pre and post exposure amplitude of TEOAE’s was analysed statistically.s Results: There was statistically significant difference between pre exposure and post-exposure amplitude of TEOAE’s. Pre and post exposure values for A & B amplitudes showed p-value of 0.0001 whereas values for A-B amplitude showed p-value of 0.0001. Conclusion: Measurement of TEOAE’s can detect early changes in the functioning of outer hair cells which cannot be picked by routine pure tone audiometry. Thus they can be used in assessing early changes in cochlear function following exposure to noise in individuals exposed to sudden noise or working in noisy environments. Thus preventive methods to reduce the noise induced hearing loss in such individuals can be implemented. PMID:25386468

Reddy, Prasen; M M, Kavitha; Khavasi, Prabhu; Doddamani, S S

2014-01-01

363

Narrow spectral emission CaMoO4: Eu3+, Dy3+, Tb3+ phosphor crystals for white light emitting diodes  

NASA Astrophysics Data System (ADS)

Alkaline earth metal molybdates are promising candidates as a host material for high efficiency narrow spectral emission phosphors. These phosphors could potentially be used for the fabrication of phosphor-converted light emitting diodes (pc-LEDs). Phosphor crystals of calcium molybdate doped with rare earth dopant Ln3+(Ln=Eu, Dy, Tb) grown using flux growth method have been shown to exhibit higher excitation efficiency than the powders synthesized by solid-state reaction process. Molybdenum (VI) oxide has been found to be a suitable flux for growing large size optically transparent high quality crystals at a temperature around 1100 °C. Using the excitation wavelengths of 465 nm, 454 nm and 489 nm for CaMoO4: Eu3+, CaMoO4: Dy3+ and CaMoO4: Tb3+, respectively, intense emission lines at wavelengths of 615 nm, 575 nm and 550 nm were observed. The optimized doping concentrations of 12%, 2% and 5% for Eu3+, Dy3+ and Tb3+, respectively, provided the highest luminescence intensity.

Khanna, A.; Dutta, P. S.

2013-02-01

364

Discovery of a TiO emission band in the infrared spectrum of the S star NP Aurigae  

NASA Astrophysics Data System (ADS)

We report on the discovery of an infrared emission band in the Spitzer spectrum of the S-type AGB star NP Aurigae that is caused by TiO molecules in the circumstellar environment. We modeled the observed emission to derive the temperature of the TiO molecules (?600 K), an upper limit on the column density (?1017.25 cm-2) and a lower limit on the spatial extent of the layer that contains these molecules. (?4.6 R?). This is the first time that this TiO emission band is observed. A search for similar emission features in the sample of S-type stars yielded two additional candidates. However, owing to the additional dust emission, the identification is less stringent. By comparing the stellar characteristics of NP Aur to those of the other stars in our sample, we find that all stars with TiO emission show large-amplitude pulsations, s-process enrichment, and a low C/O ratio. These characteristics might be necessary requirements for a star to show TiO in emission, but they are not sufficient.

Smolders, K.; Verhoelst, T.; Neyskens, P.; Blommaert, J. A. D. L.; Decin, L.; Van Winckel, H.; Van Eck, S.; Sloan, G. C.; Cami, J.; Hony, S.; De Cat, P.; Menu, J.; Vos, J.

2012-07-01

365

Structural phase transition, narrow band gap, and room-temperature ferromagnetism in [KNbO{sub 3}]{sub 1?x}[BaNi{sub 1/2}Nb{sub 1/2}O{sub 3??}]{sub x} ferroelectrics  

SciTech Connect

Structural phase transition, narrow band gap (E{sub g}), and room-temperature ferromagnetism (RTFM) have been observed in the [KNbO{sub 3}]{sub 1?x}[BaNi{sub 1/2}Nb{sub 1/2}O{sub 3??}]{sub x} (KBNNO) ceramics. All the samples have single phase perovskite structure, but exhibit a gradual transition behaviour from the orthorhombic to a cubic structure with the increase of x. Raman spectroscopy analysis not only corroborates this doping-induced change in normal structure but also shows the local crystal symmetry for x ? 0.1 compositions to deviate from the idealized cubic perovskite structure. A possible mechanism for the observed specific changes in lattice structure is discussed. Moreover, it is noted that KBNNO with compositions x?=?0.1–0.3 have quite narrow E{sub g} of below 1.5?eV, much smaller than the 3.2?eV band gap of parent KNbO{sub 3} (KNO), which is due to the increasing Ni 3d electronic states within the gap of KNO. Furthermore, the KBNNO materials present RTFM near a tetragonal to cubic phase boundary. With increasing x from 0 to 0.3, the magnetism of the samples develops from diamagnetism to ferromagnetism and paramagnetism, originating from the ferromagnetic–antiferromagnetic competition. These results are helpful in the deeper understanding of phase transitions, band gap tunability, and magnetism variations in perovskite oxides and show the potential role, such materials can play, in perovskite solar cells and multiferroic applications.

Zhou, Wenliang; Yang, Pingxiong, E-mail: pxyang@ee.ecnu.edu.cn; Chu, Junhao [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Deng, Hongmei [Instrumental Analysis and Research Center, Institute of Materials, Shanghai University, 99 Shangda Road, Shanghai 200444 (China)

2014-09-15

366

Narrow spectral emission CaMoO{sub 4}: Eu{sup 3+}, Dy{sup 3+}, Tb{sup 3+} phosphor crystals for white light emitting diodes  

SciTech Connect

Alkaline earth metal molybdates are promising candidates as a host material for high efficiency narrow spectral emission phosphors. These phosphors could potentially be used for the fabrication of phosphor-converted light emitting diodes (pc-LEDs). Phosphor crystals of calcium molybdate doped with rare earth dopant Ln{sup 3+}(Ln=Eu, Dy, Tb) grown using flux growth method have been shown to exhibit higher excitation efficiency than the powders synthesized by solid-state reaction process. Molybdenum (VI) oxide has been found to be a suitable flux for growing large size optically transparent high quality crystals at a temperature around 1100 Degree-Sign C. Using the excitation wavelengths of 465 nm, 454 nm and 489 nm for CaMoO{sub 4}: Eu{sup 3+}, CaMoO{sub 4}: Dy{sup 3+} and CaMoO{sub 4}: Tb{sup 3+}, respectively, intense emission lines at wavelengths of 615 nm, 575 nm and 550 nm were observed. The optimized doping concentrations of 12%, 2% and 5% for Eu{sup 3+}, Dy{sup 3+} and Tb{sup 3+}, respectively, provided the highest luminescence intensity. - Graphical Abstract: CaMoO{sub 4}: Eu{sup 3+} phosphor crystals grown using a molybdenum (VI) oxide flux exhibited around 1.5 times the emission intensity of powders obtained from solid-state reaction at the same synthesis temperature. These crystals were found to efficiently emit 615 nm red light when excited by near UV light up to a wavelength of 395 nm. Highlights: Black-Right-Pointing-Pointer CaMoO{sub 4}: Ln{sup 3+} (Ln=Eu{sup 3+}, Dy{sup 3+}, Tb{sup 3+}) phosphor crystals were successfully grown using high temperature flux (solutions) containing molybdenum (VI) oxide or lithium chloride. Black-Right-Pointing-Pointer Narrow spectral emission at 615 nm, 575 nm and 550 nm, respectively, was observed from CaMoO{sub 4}: Ln{sup 3+} (Ln=Eu{sup 3+}, Dy{sup 3+}, Tb{sup 3+}) phosphor crystals. Black-Right-Pointing-Pointer The optimized doping concentrations of Eu{sup 3+}, Dy{sup 3+}, Tb{sup 3+} in CaMoO{sub 4} for highest emission intensity were determined to be 12%, 2% and 5%, respectively. Black-Right-Pointing-Pointer The CaMoO{sub 4}: Ln{sup 3+} (Ln=Eu{sup 3+}, Dy{sup 3+}, Tb{sup 3+}) phosphor crystals grown with molybdenum (VI) oxide flux exhibited 50% higher emission intensity compared to the crystals grown with lithium chloride flux and the powders synthesized by solid-state reaction.

Khanna, A. [Smart Lighting Engineering Research Center, 110, 8th Street, Troy, New York, 12180 (United States) [Smart Lighting Engineering Research Center, 110, 8th Street, Troy, New York, 12180 (United States); Electrical, Computer and Systems Engineering Department, Rensselaer Polytechnic Institute, 110, 8th Street, Troy, New York, 12180 (United States); Dutta, P.S., E-mail: duttap@rpi.edu [Smart Lighting Engineering Research Center, 110, 8th Street, Troy, New York, 12180 (United States); Electrical, Computer and Systems Engineering Department, Rensselaer Polytechnic Institute, 110, 8th Street, Troy, New York, 12180 (United States)

2013-02-15

367

Out-of-band emission suppression techniques based on a generalized OFDM framework  

NASA Astrophysics Data System (ADS)

Orthogonal frequency division multiplexing (OFDM)-based cognitive radio (CR) systems suffer from the large out-of-band emission (OOBE) that may interfere with other users. Since most existing OFDM OOBE suppression schemes are derived on the base of an original OFDM system without any other scheme, we first propose a generalized OFDM framework that is capable of describing these schemes no matter whether any one or more of the schemes is applied. Then, according to the place where these schemes are implemented in our framework, they are classified into three groups, namely symbol mapping techniques, precoding techniques, and time-domain techniques. Finally, based on the proposed framework, we propose three new schemes by combining a precoding scheme named singular value decomposition (SVD) precoding with three other schemes from the three groups, namely spectral precoding, N-continuous symbol mapping, and filtering. Numerical results show the power spectral density (PSD), peak-to-average power ratio (PAPR), and bit error rate (BER) performances of the three proposed schemes. Since the individual schemes have complementary characteristics, the three proposed combined schemes are constructed to maintain the merits and avoid the drawbacks of the individual schemes involved. Thus, it is demonstrated that the proposed framework can be employed to develop other new combined OOBE suppression schemes tailoring to some specific practical needs.

You, Zihao; Fang, Juan; Lu, I.-Tai

2014-12-01

368

The GROUSE project. III. Ks-band observations of the thermal emission from WASP-33b  

NASA Astrophysics Data System (ADS)

Context. In recent years, day-side emission from about a dozen hot Jupiters has been detected through ground-based secondary eclipse observations in the near-infrared. These near-infrared observations are vital for determining the energy budgets of hot Jupiters, since they probe the planet's spectral energy distribution near its peak. Aims: The aim of this work is to measure the Ks-band secondary eclipse depth of WASP-33b, the first planet discovered to transit an A-type star. This planet receives the highest level of irradiation of all transiting planets discovered to date. Furthermore, its host-star shows pulsations and is classified as a low-amplitude ? Scuti. Methods: As part of our GROUnd-based Secondary Eclipse (GROUSE) project we have obtained observations of two separate secondary eclipses of WASP-33b in the Ks-band using the LIRIS instrument on the William Herschel Telescope (WHT). The telescope was significantly defocused to avoid saturation of the detector for this bright star (K ~ 7.5). To increase the stability and the cadence of the observations, they were performed in staring mode. We collected a total of 5100 and 6900 frames for the first and the second night respectively, both with an average cadence of 3.3 s. Results: On the second night the eclipse is detected at the 12 -? level, with a measured eclipse depth of 0.244-0.020+0.027%. This eclipse depth corresponds to a brightness temperature of 3270-160+115 K. The measured brightness temperature on the second night is consistent with the expected equilibrium temperature for a planet with a very low albedo and a rapid re-radiation of the absorbed stellar light. For the other night the short out-of-eclipse baseline prevents good corrections for the stellar pulsations and systematic effects, which makes this dataset unreliable for eclipse depth measurements. This demonstrates the need of getting a sufficient out-of-eclipse baseline. Appendix A is available in electronic form at http://www.aanda.orgLight curves are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/550/A54

de Mooij, E. J. W.; Brogi, M.; de Kok, R. J.; Snellen, I. A. G.; Kenworthy, M. A.; Karjalainen, R.

2013-02-01

369

L-Band H Polarized Microwave Emission During the Corn Growth Cycle  

NASA Technical Reports Server (NTRS)

Hourly L-band (1.4 GHz) horizontally (H) polarized brightness temperatures (T(sub B))'s measured during five episodes (more than two days of continuous measurements) of the 2002 corn growth cycle are analyzed. These T(sub B)'s measurements were acquired as a part of a combined active/passive microwave field campaign, and were obtained at five incidence and three azimuth angles relative to the row direction. In support of this microwave data collection, intensive ground sampling took place once a week. Moreover, the interpretation of the hourly T(sub B)'s could also rely on the data obtained using the various automated instruments installed in the same field. In this paper, the soil moisture and temperature measured at fixed time intervals have been employed as input for the tau-omega model to reproduce the hourly T(sub B). Through the calibration of the vegetation and surface roughness parameterizations, the impact of the vegetation morphological changes on the microwave emission and the dependence of the soil surface roughness parameter, h(sub r), on soil moisture are investigated. This analysis demonstrates that the b parameter, appearing in the representation of the canopy opacity, has an angular dependence that varies throughout the growing period and also that the parameter hr increases as the soil dries in a portion of the dry-down cycle. The angular dependence of the b parameter imposes the largest uncertainty on T(sub B) simulations near senescence as the response of b to the incidence is also affected by the crop row orientation. On the other hand, the incorporation of a soil moisture dependent h(sub r) parameterization was responsible for the largest error reduction of T(sub B) simulations in the early growth cycle.

Joseph, A. T.; va der Velde, R.; O'Neill, P. E.; Kim, E.; Lang, R. H.; Gish, T.

2012-01-01

370

Evaluation of Terra and Aqua MODIS thermal emissive band response versus scan angle  

NASA Astrophysics Data System (ADS)

Terra and Aqua MODIS have operated near-continuously for over 14 and 12 years, respectively, and are key instruments for NASA's Earth Observing System. Observations from the 16 thermal emissive bands (TEB), covering wavelengths from 3.5 to 14.4 ?m with a nadir spatial resolution of 1 km are used to regularly generate a variety of atmosphere, ocean and land science products. The TEB detectors are calibrated using scan-by-scan observations of an on-board blackbody (BB). The current response versus scan angle (RVS) of the scan mirror was derived using a spacecraft deep-space pitch maneuver for Terra MODIS and characterized during prelaunch for Aqua MODIS. Earth view (EV) data over the complete range of angles of incidence (AOI) can be used to evaluate the on-orbit performance of the TEB RVS over the mission lifetime. Three approaches for tracking the TEB RVS on-orbit using EV observations are formulated. The first approach uses the multiple daily observations of Dome C BT at different AOI and their trend relative to coincident measurements from a ground temperature sensor. The second approach uses brightness temperatures (BT) retrieved over the cloud-free ocean to derive the trends at 13 AOI over the mission lifetime. The third approach tracks the dn response (normalized to the BB AOI) across the full swath width for Antarctic granules with the Dome C site at nadir. The viability of the three approaches is assessed and the long-term stability of the TEB RVS for both MODIS instruments is determined.

Wenny, B. N.; Wu, A.; Madhavan, S.; Xiong, X.

2014-10-01

371

Methane oxidation behind reflected shock waves: Ignition delay times measured by pressure and flame band emission  

NASA Technical Reports Server (NTRS)

Ignition delay data were recorded for three methane-oxygen-argon mixtures (phi = 0.5, 1.0, 2.0) for the temperature range 1500 to 1920 K. Quiet pressure trances enabled us to obtain delay times for the start of the experimental pressure rise. These times were in good agreement with those obtained from the flame band emission at 3700 A. The data correlated well with the oxygen and methane dependence of Lifshitz, but showed a much stronger temperature dependence (phi = 0.5 delta E = 51.9, phi = 1.0 delta = 58.8, phi = 2.0 delta E = 58.7 Kcal). The effect of probe location on the delay time measurement was studied. It appears that the probe located 83 mm from the reflecting surface measured delay times which may not be related to the initial temperature and pressure. It was estimated that for a probe located 7 mm from the reflecting surface, the measured delay time would be about 10 microseconds too short, and it was suggested that delay times less than 100 microsecond should not be used. The ignition period was defined as the time interval between start of the experimental pressure rise and 50 percent of the ignition pressure. This time interval was measured for three gas mixtures and found to be similar (40 to 60 micro sec) for phi = 1.0 and 0.5 but much longer (100 to 120) microsecond for phi = 2.0. It was suggested that the ignition period would be very useful to the kinetic modeler in judging the agreement between experimental and calculated delay times.

Brabbs, T. A.; Robertson, T. F.

1986-01-01

372

Large-amplitude, narrow-linewidth microwave emission in a dual free-layer MgO spin-torque oscillator  

NASA Astrophysics Data System (ADS)

Synchronized magnetization motion among the several magnetic layers composing a spin-torque oscillator (STO) is considered an effective way to improve spectral purity. To utilize this scheme in a MgO-based STO, we have fabricated a dual free-layer STO composed of a CoFeB free layer (FL), a MgO barrier layer, and a CoFe/Ru/CoFeB synthetic ferrimagnet free layer (SyF). Unlike conventional MgO-based STOs, this structure does not have an antiferromagnetic layer that pins the SyF, leading to a large-amplitude oscillation of magnetization in the SyF. The dual free-layer STO exhibits coherent microwave emissions with power spectrum density beyond 800 nW/GHz and narrow spectral linewidth below 5 MHz (Q-factor ? 2000). Macrospin simulations confirm that the stable oscillations originate from the synchronized magnetization motion of the FL and the SyF through dynamical dipolar coupling.

Nagasawa, Tazumi; Kudo, Kiwamu; Suto, Hirofumi; Mizushima, Koichi; Sato, Rie

2014-11-01

373

Estimating net rainfall, evaporation and water storage of a bare soil from sequential L-band emissivities  

NASA Technical Reports Server (NTRS)

A general method to use a time series of L-band emissivities as an input to a hydrological model for continuously monitoring the net rainfall and evaporation as well as the water content over the entire soil profile is proposed. The model requires a sufficiently accurate and general relation between soil emissivity and surface moisture content. A model which requires the soil hydraulic properties as an additional input, but does not need any weather data was developed. The method is shown to be numerically consistent.

Stroosnijder, L.; Lascano, R. J.; Newton, R. W.; Vanbavel, C. H. M.

1984-01-01

374

Monitoring MRK 509: The Origin of the Reprocessor and Broad Band X-ray Spectrum of Narrow Line Seyfert 1 AKN 564  

NASA Technical Reports Server (NTRS)

The ten monitoring observations of Mrk 509 were made successfully between October 20 and November 26 last year. These observations were simultaneously with RXTE observations. A preliminary analysis of the RXTE observations has been done, and the light curve is shown in figure 1. Our aim in this experiment is to determine the location of the emission region of the reflection component by reverberation mapping. This component could be emitted from the accretion disk, within 100 Scwartzschild radii (R(sub s)) from the source. Note that the monitoring interval of 2.5 days corresponds to 100 R(sub s) for a 2 x 10(exp 8) solar mass black hole, which may be appropriate for this luminous object. In that case, we would expect the reflected component to vary along the direct flux, and there should be no spectral variability between observations. Alternatively, the reflected emission could come from the molecular torus, several parsecs from the nucleus. In that case, the reflection component flux should not vary. The light curve in figure 1 shows that during the monitoring period, the target varied in an ideal way, since significant variability was observed between observations and yet the most rapid variability is apparently sampled. The analysis of this data is not yet completed. The measurement of the reflection component in the combined ASCa and RXTE spectra depends critically on the RXTE background subtraction and calibration, but these have not yet progressed to the point where the analysis can be done.

Halpern, Jules P.; Leighly, Karen M.

1998-01-01

375

Emission Cross Sections of the Lyman-Birge-Hopfield Band System in Molecular Nitrogen Induced by Electron Impact Excitation  

NASA Astrophysics Data System (ADS)

Emissions from the Lyman-Birge-Hopfield (LBH) band system in N2 (a 1?g ? X 1?g+) are the most prominent molecular features below 180 nm in the Earth's atmosphere [Kanik et al., Phys. Chem. Earth (C), 25, 573, 2000]. LBH emissions continue to be of interest as a sensitive test of N2 density distributions and photoelectron flux in the dayglow and secondary electron flux in the aurora. Furthermore, recent measurements with the onboard Ultraviolet Imaging Spectrograph (UVIS) experiment by the Cassini spacecraft of the Saturnian system, in particular Titan, have invigorated the need for improved N2 cross sections. The present work utilized a large vacuum chamber, a detector platform that provided vertical and horizontal movement, a Faraday cup, and an electron gun providing an electron beam of fixed energy. The detector platform enabled the LBH emissions to be observed, using the UVIS engineering flight spare, at multiple radial positions relative to the electron beam axis, which was used to map the glow resulting from electron impact excitation of an optically thin swarm of N2 gas. Normalization of the LBH emissions was provided by comparison with well known NI emissions. The absolute 100 eV LBH emission cross section was used to renormalize the LBH emission cross sections of [Ajello and Shemansky, JGR, 90, 9845, 1985]. Acknowledgement: This work was carried out at JPL, Caltech, under contract with NASA and at LASP, UC (Boulder). This research was performed while CPM held a NRC Research Associateship Award at JPL.

Malone, C. P.; Johnson, P. V.; Ajello, J. M.; Kanik, I.

2005-12-01

376

Coupling of narrow and wide band-gap semiconductors on uniform films active in bacterial disinfection under low intensity visible light: implications of the interfacial charge transfer (IFCT).  

PubMed

This study reports the design, preparation, testing and surface characterization of uniform films deposited by sputtering Ag and Ta on non-heat resistant polyester to evaluate the Escherichia coli inactivation by TaON, TaN/Ag, Ag and TaON/Ag polyester. Co-sputtering for 120 s Ta and Ag in the presence of N? and O? led to the faster E. coli inactivation by a TaON/Ag sample within ?40 min under visible light irradiation. The deconvolution of TaON/Ag peaks obtained by X-ray photoelectron spectroscopy (XPS) allowed the assignment of the Ta?O? and Ag-species. The shifts observed for the XPS peaks have been assigned to AgO to Ag?O and Ag(0), and are a function of the applied sputtering times. The mechanism of interfacial charge transfer (IFCT) from the Ag?O conduction band (cb) to the lower laying Ta?O? (cb) is discussed suggesting a reaction mechanism. The optical absorption of the TaON and TaON/Ag samples found by diffuse reflectance spectroscopy (DRS) correlated well with the kinetics of E. coli inactivation. The TaON/Ag sample microstructure was characterized by contact angle (CA) and by atomic force microscopy (AFM). Self-cleaning of the TaON/Ag polyester after each disinfection cycle enabled repetitive E. coli inactivation. PMID:23867967

Rtimi, S; Sanjines, R; Pulgarin, C; Houas, A; Lavanchy, J-C; Kiwi, J

2013-09-15

377

Narrowband ultraviolet field-emission device using Gd-doped AlN  

Microsoft Academic Search

We developed mercury-free narrow-band deep-ultraviolet luminescence devices which were accomplished by performing field-emission excitation of Al1-xGdxN. The narrow band emission is a typical feature of the intra-orbital electron transition in the rare-earth Gd3+ ions. AlN, GdN and Al1-xGdxN thin films were grown on fused silica substrates by using the reactive sputtering technique. A resolution limited, narrow band luminescence line from

Shinya Kitayama; Takashi Kita; Masashi Kawamura; Osamu Wada; Yoshitaka Chigi; Yoshihiro Kasai; Tetsuro Nishimoto; Hiroyuki Tanaka; Mikihiro Kobayashi

2009-01-01

378

Acoustic emissions and porosity reduction during growth of discrete compaction bands in porous sandstone  

Microsoft Academic Search

Recent field and laboratory studies have documented the occurrence of strain localisation in porous sandstones. The localised failure mode can be in shear or compaction, in the form of conjugate shear or compaction bands oriented at relatively high angles to the maximum compression direction. Compaction bands in particular have drawn a lot of interest because these localized structures could potentially

P. Baud; P. Meredith; S. Boon

2003-01-01

379

Wavelength Shifts of the 7.7 Micron Emission Band in Reflection Nebulae  

NASA Technical Reports Server (NTRS)

Using spatial-spectral data cubes of reflection nebulae obtained by ISOCAM, we have observed a shift in the central wavelength of the 7.7 micron band within several reflection nebulae. The band shifts progressively from approx. 7.8 microns near the edge of the nebulae to approx. 7.6 microns towards the center of the nebulae. The ratio of the 11.3/7.7 micron bands also changes with distance from the central star, first rising from the center towards the edge of the nebula, then falling at the largest distances from the star, consistent with the 11.3/7.7 micron band ratio being controlled by the PAH ionization state. The behavior of the 7.7 micron band center can be explained either by assuming that anions are the origin of the 7.85 micron band and cations the 7.65 micron band, or that the band center wavelength depends on the chemical nature of the PAHs.

Bregman, Jesse; Temi, Pasquale

2003-01-01

380

Laboratory studies of UV emissions of H2 by electron impact - The Werner- and Lyman-band systems  

NASA Technical Reports Server (NTRS)

The vacuum ultraviolet electron-impact-induced fluorescence emissions of H2 were studied for the Lyman and Werner band systems in the range of 120-170 nm, using an optical system containing a photomultiplier and a spectrometer, over an energy range from threshold to 400 eV. The emission cross sections for the Lyman and Werner transitions at 100 eV are determined. The cross-section ratio is in excellent agreement with theoretical calculations and experimental data for the optical oscillator strengths. The cross-section for cascading to the B state is stated as a percentage of the total emission cross section at both 100 and 300 eV, increasing substantially at 20 eV. The vibrational population distribution of the B state is found to be a function of electron-impact energy as the importance of cascading relative to direct excitation changes with electron-impact energy.

Ajello, J. M.; Srivastava, S. K.; Yung, Y. L.

1982-01-01

381

L-band automatic-gain-controlled erbium-doped fiber amplifier utilizing C-band backward-amplified spontaneous emission and electrical feedback monitor.  

PubMed

A new L-band automatic-gain-controlled (AGC) erbium-doped fiber amplifier (EDFA) for dense wavelength-division-multiplexing transmission systems is presented, in which a single 1480 nm laser with an internal thermoelectric cooler is used as a primary pump for stable amplification. All C-band amplified spontaneous emission (ASE) is recycled by the secondary pump to enhance the gain efficiency. A fraction of the output signal is used as an electrical feedback monitor for the AGC to improve the gain-clamped (GC) flatness. Experimental results prove that the AGC EDFA has a gain flatness of better than 0.46 dB/40 nm, i.e., below 1.5%, and a higher gain of approximately 36.5 dB compared to that of approximately 35.3 dB for the conventional GC EDFA at -30 dBm input signal power. The best gain flatness of +/-0.25 dB can be achieved over the dynamic range greater than 20 dB. The dynamic range of noise figure is between 6.7 and 7.1. The 3 dB down bandwidth is more than 40 nm. Overall dynamics measurements for the AGC EDFA feedback stabilization have been carried out. The recorded corresponding rise time of 1.565 ms indicates that the system does not exhibit any overshoot of gain or ASE variation due to the signal at the beginning of the pulse. PMID:19209194

Shen, Jyi-Lai; Lee, Yueh-Chien; Huang, Chia-Chih

2009-02-10

382

Effect of multiple conduction bands on high-harmonic emission from dielectrics  

NASA Astrophysics Data System (ADS)

We find that, for sufficiently strong mid-IR fields, transitions between different conduction bands play an important role in the generation of high-order harmonics in a dielectric. The transitions make a significant contribution to the harmonic signal, and they can create a single effective band for the motion of an electron wave packet. We show how high harmonic spectra produced during the interaction of ultrashort laser pulses with periodic solids provide a spectroscopic tool for understanding the effective band structure that controls electron dynamics in these media.

Hawkins, Peter G.; Ivanov, Misha Yu.; Yakovlev, Vladislav S.

2015-01-01

383

The Effect of Multiple Conduction Bands on High Harmonic Emission from Dielectrics  

E-print Network

We find that, for sufficiently strong mid-IR fields, transitions between different conduction bands play an important role in the generation of high-order harmonics in a dielectric. The transitions make a significant contribution to the harmonic signal, and they can create a single effective band for the motion of an electron wave packet. We show how high harmonic spectra produced during the interaction of ultrashort laser pulses with periodic solids provide a spectroscopic tool for understanding the effective band structure that controls electron dynamics in these media.

Peter G. Hawkins; Misha Yu. Ivanov; Vladislav S. Yakovlev

2014-09-19

384

PAH Emission in the Orion Bar  

NASA Technical Reports Server (NTRS)

The emission from polycyclic aromatic hydrocarbons (PAH's) in the Orion Bar region is investigated using a combination of narrow-band imaging and long-slit spectroscopy. The goal was to study how the strength of the PAH bands vary with spatial position in this edge-on photo-dissociation region. The specific focus here is how these variations constrain the carrier of the 3.4 micron band.

Bregman, Jesse; Sloan, G. C.

1996-01-01

385

Modeled and Observed N2 Lyman-Birge-Hopfield Band Emissions Earth's Dayglow: A Comparison.  

E-print Network

??Ultraviolet (UV) spectra obtained from Earth's dayglow contain important information for understanding the thermosphere, and the N2 Lyman-Birge-Hopfield (LBH) bands are possibly the most useful… (more)

Murray, Donald

2007-01-01

386

The ALI-ARMS Code for Modeling Atmospheric non-LTE Molecular Band Emissions: Current Status and Applications  

NASA Technical Reports Server (NTRS)

The Accelerated Lambda Iteration (ALI) technique was developed in stellar astrophysics at the beginning of 1990s for solving the non-LTE radiative transfer problem in atomic lines and multiplets in stellar atmospheres. It was later successfully applied to modeling the non-LTE emissions and radiative cooling/heating in the vibrational-rotational bands of molecules in planetary atmospheres. Similar to the standard lambda iterations ALI operates with the matrices of minimal dimension. However, it provides higher convergence rate and stability due to removing from the iterating process the photons trapped in the optically thick line cores. In the current ALI-ARMS (ALI for Atmospheric Radiation and Molecular Spectra) code version additional acceleration of calculations is provided by utilizing the opacity distribution function (ODF) approach and "decoupling". The former allows replacing the band branches by single lines of special shape, whereas the latter treats non-linearity caused by strong near-resonant vibration-vibrational level coupling without additional linearizing the statistical equilibrium equations. Latest code application for the non-LTE diagnostics of the molecular band emissions of Earth's and Martian atmospheres as well as for the non-LTE IR cooling/heating calculations are discussed.

Kutepov, A. A.; Feofilov, A. G.; Manuilova, R. O.; Yankovsky, V. A.; Rezac, L.; Pesnell, W. D.; Goldberg, R. A.

2008-01-01

387

Laboratory studies of UV emissions from proton impact on N2: The Lyman-Birge-Hopfield band system for aurora analysis  

Microsoft Academic Search

We have measured the emission cross sections of the Lyman-Birge-Hopfield (LBH) a 1Pig - X 1Sigmag+ band system and several atomic nitrogen (N I) multiplets (1200, 1243, 1493 Å) by H+ (proton) impact on N2 over an impact energy range of 1-7 keV. The peak proton-impact-induced emission cross section of the LBH band system (1260-2500 Å) was measured to be

Joseph M. Ajello; Rao S. Mangina; Douglas J. Strickland; Dariusz Dziczek

2011-01-01

388

Direct imaging of the visible emission bands from individual ZnO nanowires by near-field optical spectroscopy.  

PubMed

Room-temperature photoluminescence (PL) measurements have been performed on single-crystal ZnO nanowires grown on SiO2/Si and quartz substrates by the vapor transport method using Au as a catalyst. Two emission bands are apparent, one in the UV spectral region around 380 nm (3.26 eV) associated with exciton recombination processes and a much broader structure in the visible range from 420 to 700 nm, which exhibits two distinct peak-like features around 520 and 590 nm (2.38 and 2.10 eV). Spectrally resolved scanning near-field optical microscopy (SNOM) of single ZnO nanowires have been performed for a direct imaging of the PL emission with spatial resolution below 100 nm. SNOM results provide evidence that the yellow emission band observed at 590 nm is a unique property of the ZnO nanowires, being most likely related to radiative recombination processes associated with Au impurities introduced during the catalytic growth. PMID:19597252

Güell, F; Ossó, J O; Goñi, A R; Cornet, A; Morante, J R

2009-08-01

389

Pre-launch characterization of aqua MODIS scan mirror response versus scan angle for thermal emissive bands  

NASA Astrophysics Data System (ADS)

The double-sided paddle wheel scan mirror is the key optical component of the Moderate Resolution Imaging Spectroradiometer (MODIS) on-board the NASA EOS Terra and Aqua satellites. At a constant rotating speed, the scan mirror continuously reflects the Earth's top-of-atmosphere radiances through the instrument nadir aperture door and onto four focal plane assemblies (FPA), which consist of 36 spectral bands. Of those 36 bands, 16 are thermal emissive bands (TEB) with wavelengths ranging from 3.7 to 14.4?m. While this cross-track scanning system provides the Earth scene observations over a range of +/-55° viewing angles from the nadir, the on-orbit calibration for TEB is performed by an On-Board Calibrator Blackbody (OBC BB) at a fixed viewing angle. The response versus scan angle (RVS) of the scan mirror is sensitive to the MODIS radiometric calibration. This paper describes how the pre-launch TEB RVS of the Aqua MODIS was characterized at the instrument system level by using ground support equipment, a Blackbody Calibration Source (BCS). The RVS test setup, test procedure, data analysis, derivation of RVS, and the fitting uncertainty are discussed in the paper. A separate paper that gives similar RVS analysis for the MODIS Reflective Solar Bands (RSB) is presented in this proceeding.

Chiang, Kwo-Fu; Xiong, Xiaoxiong

2007-09-01

390

Azimuthal Variation of the Emissivity of Foam From C and X Band Polarimetric Measurements  

Microsoft Academic Search

Sea foam increases surface emission and brightness temperature at microwave frequencies. Together with the surface roughness, it is a key component of the signal used to obtain surface wind vector with satellite-borne radiometric and polarimetric instruments. Current knowledge of foam emissivity, however, is incomplete, particularly in regard to azimuthal effects. Since breaking waves on the open ocean are intermittent and

L. A. Rose; J. P. Bobak; P. W. Gaiser; M. D. Anguelova; D. J. Dowgiallo; W. E. Asher; S. C. Reising; S. Padmanabhan

2006-01-01

391

Imaging Jupiter's aurorae from H3+ emissions in the 3-4 micrometers band  

NASA Technical Reports Server (NTRS)

Since H3+ was first spectroscopically detected on Jupiter, there has been considerable interest in using this simple molecular ion to probe conditions existing in the planet's auroral regions. Here we present a series of images of Jupiter recorded at wavelengths sensitive to emission by H3+, which reveal the spatial distribution of excited H3+ molecular ions in the jovian ionosphere, as seen from Earth. We believe that they provide high-spatial-resolution images of polar aurorae on Jupiter. They suggest that the intensity of the auroral emission can vary on a timescale of an hour, a shorter period than had previously been noted. We also find that the spatial distribution of H3+ emissions correlates only partially with the loci of auroral activity inferred from ultraviolet and longer-wavelength infrared observations. The H3+ emission may therefore be controlled by auroral processes that are different from those responsible for the ultraviolet and infrared emissions.

Baron, R.; Joseph, R. D.; Owen, T.; Tennyson, J.; Miller, S.; Ballester, G. E.

1991-01-01

392

Enhanced photonic band edge laser emission in a cholesteric liquid crystal resonator  

NASA Astrophysics Data System (ADS)

A highly efficient photonic band edge dye-doped cholesteric liquid crystal (CLC) laser is demonstrated. By sandwiching an active CLC cell within a resonator consisting of two passive CLC reflectors, the lasing efficiency is dramatically enhanced. Theoretical analysis using the improved 4×4 transfer matrix and scattering matrix shows that the band edge laser mode can be supported by the external CLC resonator and its optimal output can be achieved by a relatively thin active CLC layer and thin passive CLC reflectors. Theoretical analysis agrees well with the experimental results.

Zhou, Ying; Huang, Yuhua; Ge, Zhibing; Chen, Liang-Pin; Hong, Qi; Wu, Thomas X.; Wu, Shin-Tson

2006-12-01

393

Tuning the light emission properties by band gap engineering in hybrid lead halide perovskite.  

PubMed

We report about the relationship between the morphology and luminescence properties of methylammonium lead trihalide perovskite thin films. By tuning the average crystallite dimension in the film from tens of nanometers to a few micrometers, we are able to tune the optical band gap of the material along with its photoluminescence lifetime. We demonstrate that larger crystallites present smaller band gap and longer lifetime, which correlates to a smaller radiative bimolecular recombination coefficient. We also show that they present a higher optical gain, becoming preferred candidates for the realization of CW lasing devices. PMID:25469762

D'Innocenzo, Valerio; Srimath Kandada, Ajay Ram; De Bastiani, Michele; Gandini, Marina; Petrozza, Annamaria

2014-12-24

394

Lugol chromo-endoscopy versus narrow band imaging for endoscopic screening of esophageal squamous-cell carcinoma in patients with a history of cured esophageal cancer: a feasibility study.  

PubMed

To date, Lugol chromo-endoscopy is the reference technique to detect an esophageal neoplasia in patients with prior esophageal squamous-cell carcinoma (ESCC), but is not easy to perform without general anesthesia, which can limit its use in routine practice. The objective of this study were to compare the accuracy of white light, narrow band imaging (NBI), and Lugol to detect esophageal neoplasia in patients with a history of cured ESCC, in a prospective study. Thirty patients were prospectively included between June 2006 and June 2009. They all had a history of cured ESCC. Esophageal mucosa was examined first using white light, second NBI, and third after Lugol staining. Histology was obtained in all abnormalities detected by white light, NBI, and/or Lugol. Five neoplastic lesions in five different patients were identified at histology, four cancers, and one high-grade dysplasia. NBI and Lugol both detected all esophageal neoplastic lesions, whereas white light detected the four cancers but missed the high-grade dysplasia. In this feasibility study, NBI and Lugol both detected all identified esophageal neoplasia in very high-risk patients of ESCC. This result suggests that NBI could be used instead of Lugol to detect an esophageal neoplasia in patients with high risk of ESCC, but needs to be confirmed in a larger study. PMID:21309914

Lecleire, S; Antonietti, M; Iwanicki-Caron, I; Duclos, A; Lemoine, F; Pessot, F L; Michel, P; Ducrotté, P; Di Fiore, F

2011-08-01

395

Non-LTE modeling of narrow emission components of He and Ca lines in optical spectra of classical T Tauri stars  

NASA Astrophysics Data System (ADS)

Using LTE calculations of the structure of T Tauri stellar atmospheres heated by radiation from an accretion shock (Dodin and Lamzin 2012), we have calculated the spectrum of the hot spot emerging on the stellar surface by taking into account non-LTE effects for He I, He II, Ca I, and Ca II. Assuming the pre-shock gas density N 0 and velocity V 0 to be the same at all points of the accretion stream cross section, we have calculated the spectrum of the star+circular spot system at various N 0, V 0, and parameters characterizing the star and the spot. Using nine stars as an example, we show that the theoretical optical spectra reproduce well the observed veiling of photospheric absorption lines as well as the profiles and intensities of the so-called narrow components of He II and Ca I emission lines with an appropriate choice of parameters. The accreted gas density in all of the investigated stars except DK Tau has been found to be N 0 > 1012 cm-3. We have managed to choose the parameters for eight stars at a calcium abundance in the accreted gas ? Ca equal to the solar one, but we have been able to achieve agreement between the calculations and observations for TW Hya only by assuming ? Ca to be approximately a factor of 3 lower than the solar one. The estimated parameters do not depend on interstellar extinction, because they have been determined from the spectra normalized to the continuum level. The calculated intensity of Ca II lines has turned out to be lower than the observed one, but this contradiction can be eliminated by assuming that, in addition to the accreted gas with a high density N 0, a more rarefied gas also falls onto the star. The theoretical equivalent widths and relative intensities of the subordinate He I lines disagree significantly with the observations. This is apparently because non-LTE effects should be taken into account when calculating the structure of the upper layers of the hot spot, the accuracy of the cross sections for collisional processes from upper levels is insufficient, and the spot inhomogeneity should probably be taken into account.

Dodin, A. V.; Lamzin, S. A.; Sitnova, T. M.

2013-05-01

396

Are the Isomers of C2H4O Responsible for the Unidentified Infrared Emission Bands and Continuum?  

NASA Astrophysics Data System (ADS)

We suggest that ethylene oxide (EO, c-C2H4O) and its isomers, acetaldehyde (AC, CH3CHO) and vinyl alcohol (VA, CH2CHOH) may be the source of the unidentified infrared bands (UIR) and their underlying continuum. Microwave transitions of all three isomers have been observed in many astronomical objects, all of which show the UIR bands. We show that the fundamental and overtone vibrational frequencies of EO correlate well with the major UIR bands at 3.3, 6.2, 7.7, 8.6, and 11.2 ?m. Two additional UIR features at 12.7 and 16.4 ?m are consistent with vibrationally excited EO, which is not collisionally quenched in space because the collision rate is negligible compared to the photon emission rate. In our mechanism, a vibrationally and rotationally cold AC molecule absorbs a 9 eV UV photon to produce vibrationally hot and rotationally cold AC in an excited electronic state. The excited AC either (1) undergoes isomerization to form vibrationally hot and rotationally cold EO in an excited electronic state, or (2) undergoes dissociation to form vibrationally and rotationally hot molecular products in excited electronic states. The electronically excited EO emits a UV photon to produce vibrationally hot and rotationally cold EO in its ground electronic state. This EO then emits its vibrational energy in the infrared (IR) and gives rise to the UIR bands. The electronically excited dissociation products also emit UV photons to produce vibrationally and rotationally hot molecules in their ground electronic states. These daughter molecules also emit in the IR and give rise to the UIR continuum. While EO and its isomers are plausible candidates for the source of the UIR spectrum, we have also found that the fundamental vibrational frequencies of cyclopropenylidene (c-C3H2) also match well with the UIR spectral bands, perhaps indicating that more than one small carbonaceous molecule (SCM) is involved.

Bernstein, Lawrence; Lynch, D. K.

2009-05-01

397

Narrow band filter photometry of Comet Kohoutek  

NASA Technical Reports Server (NTRS)

Narrowband photoelectric measurements of CN (3870), CO(+) (4250), C2 (4700), and C2 (5120) were made on twelve nights in December and January of Comet Kohoutek. CN and C2 appear to be stronger after perihelion, and CO(+) showed a strong post perihelion increase coincident with the first appearance of a strong gas tail and then decreased to a fairly constant level.

Angione, R. J.; Lanning, H.; Roosen, R. G.

1975-01-01

398

Soil moisture, dielectric permittivity and emissivity of soil: effective depth of emission measured by the L-band radiometer ELBARA  

NASA Astrophysics Data System (ADS)

Due to the large variation of soil moisture in space and in time, obtaining soil water balance with an aid of data acquired from the surface is still a challenge. Microwave remote sensing is widely used to determine the water content in soil. It is based on the fact that the dielectric constant of the soil is strongly dependent on its water content. This method provides the data in both local and global scales. Very important issue that is still not solved, is the soil depth at which radiometer "sees" the incoming radiation and how this "depth of view" depends on water content and physical properties of soil. The microwave emission comes from its entire profile, but much of this energy is absorbed by the upper layers of soil. As a result, the contribution of each layer to radiation visible for radiometer decreases with depth. The thickness of the surface layer, which significantly contributes to the energy measured by the radiometer is defined as the "penetration depth". In order to improve the physical base of the methodology of soil moisture measurements using microwave remote sensing and to determine the effective emission depth seen by the radiometer, a new algorithm was developed. This algorithm determines the reflectance coefficient from Fresnel equations, and, what is new, the complex dielectric constant of the soil, calculated from the Usowicz's statistical-physical model (S-PM) of dielectric permittivity and conductivity of soil. The model is expressed in terms of electrical resistance and capacity. The unit volume of soil in the model consists of solid, water and air, and is treated as a system made up of spheres, filling volume by overlapping layers. It was assumed that connections between layers and spheres in the layer are represented by serial and parallel connections of "resistors" and "capacitors". The emissivity of the soil surface is calculated from the ratio between the brightness temperature measured by the ELBARA radiometer (GAMMA Remote Sensing AG) and the physical temperature of the soil surface measured by infrared sensor. As the input data for S-PM: volumes of soil components, mineralogical composition, organic matter content, specific surface area and bulk density of the soil were used. Water contents in the model are iteratively changed, until emissivities calculated from the S-PM reach the best agreement with emissivities measured by the radiometer. Final water content will correspond to the soil moisture measured by the radiometer. Then, the examined soil profile will be virtually divided into thin slices where moisture, temperature and thermal properties will be measured and simultaneously modelled via S-PM. In the next step, the slices will be "added" starting from top (soil surface), until the effective soil moisture will be equal to the soil moisture measured by ELBARA. The thickness of obtained stack will be equal to desired "penetration depth". Moreover, it will be verified further by measuring the moisture content using thermal inertia. The work was partially funded by the Government of Poland through an ESA Contract under the PECS ELBARA_PD project No. 4000107897/13/NL/KML.

Usowicz, Boguslaw; Lukowski, Mateusz; Marczewski, Wojciech; Usowicz, Jerzy; Lipiec, Jerzy; Rojek, Edyta; Slominska, Ewa; Slominski, Jan

2014-05-01

399

No detection of L-band radio emission from SN 2007gr by GMRT  

NASA Astrophysics Data System (ADS)

Sayan Chakraborti (Tata Institute of Fundamental Research, Mumbai, (TIFR)), Poonam Chandra (Univ Virginia and National Radio Astronomical Observatory, Charlottesville), Nirupam Roy (National Centre for Radio Astrophysics (NCRA-TIFR), Pune, and Alak Ray (TIFR) report on the Target of Opportunity observation of SN 2007gr on 2007 Aug 24 by the Giant Metrewave Radio Telescope (GMRT) in the L-band between UT 0200 to 0400.

Ray, Alak K.

2007-08-01

400

Squaraine-based polymer dots with narrow, bright near-infrared fluorescence for biological applications.  

PubMed

This article describes the design and development of squaraine-based semiconducting polymer dots (Pdots) that show large Stokes shifts and narrow-band emissions in the near-infrared (NIR) region. Fluorescent copolymers containing fluorene and squaraine units were synthesized and used as precursors for preparing the Pdots, where exciton diffusion and likely through-bond energy transfer led to highly bright and narrow-band NIR emissions. The resulting Pdots exhibit the emission full width at half-maximum of ?36 nm, which is ?2 times narrower than those of inorganic quantum dots in the same wavelength region (?66 nm for Qdot705). The squaraine-based Pdots show a high fluorescence quantum yield (QY) of 0.30 and a large Stokes shift of ?340 nm. Single-particle analysis indicates that the average per-particle brightness of the Pdots is ?6 times higher than that of Qdot705. We demonstrate bioconjugation of the squaraine Pdots and employ the Pdot bioconjugates in flow cytometry and cellular imaging applications. Our results suggest that the narrow bandwidth, high QY, and large Stokes shift are promising for multiplexed biological detections. PMID:25494172

Wu, I-Che; Yu, Jiangbo; Ye, Fangmao; Rong, Yu; Gallina, Maria Elena; Fujimoto, Bryant S; Zhang, Yong; Chan, Yang-Hsiang; Sun, Wei; Zhou, Xing-Hua; Wu, Changfeng; Chiu, Daniel T

2015-01-14

401

Dayglow and auroral emissions of Uranus in H2 FUV bands  

NASA Astrophysics Data System (ADS)

Following the recent detection of an auroral signal on Uranus (Lamy et al. [2012]. Geophys. Res. Lett. 39, 7105) during HST/STIS observation performed in November 2011, we analyzed the associated HST/STIS FUV spectral images obtained in 2011 and 2012. Our purpose was to extract any possible H2 emission produced in the upper atmosphere of the planet. To interpret these data, we adapted a version of the kinetic Trans* code to the Uranian case. This code simulates the H2 emissions created by energetic particle precipitations in the upper atmosphere. The signal measured in the 1330-1700 Å range, of around 1.8 kR, is composed mostly of reflected sunlight with a small contribution from upper atmospheric emissions. For most spectra, we found no evidence of particle precipitation, indicating a precipitation flux smaller than 0.01 erg cm-2 s-1. For the spectrum of 29 November 2011 however, when an auroral spot was positively detected, we additionally identified a small contribution of H2 emission which requires a precipitating energy flux up to 0.05 erg cm-2 s-1. This study also establishes that the Hubble Space Telescope (HST) can be used to monitor the aurorae on Uranus in its image and spectral modes, and to estimate the associated precipitated energy flux, provided a very careful data processing is applied.

Barthélemy, M.; Lamy, L.; Menager, H.; Schulik, M.; Bernard, D.; Abgrall, H.; Roueff, E.; Cessateur, G.; Prange, R.; Lilensten, J.

2014-09-01

402

Enhanced near-band edge emission from ZnO nanorods by V2Os coating and subsequent thermal annealing.  

PubMed

V2O5-coated ZnO 1D nanostructures were prepared by using a two step process: thermal evaporation of a mixture of ZnO and graphite powders (ZnO:C = 1:1) in an oxidative atmosphere and sputter-deposition of V2O5. Scanning electron microscopy revealed that the nanostructures had a rod-like morphology with the thickness diminishing gradually from an end to the other. The thicknesses and lengths of the nanorods range from a few tens to a few hundreds of nanometers and from a few to a few tens of micrometers, respectively. Transmission electron microscopy and X-ray diffraction analyses revealed that the ZnO cores and V2O5 shells of the core-shell nanorods were wurtzite-type hexagonal close-packed structured single crystal and amorphous, respectively. The intensity ratio of the near-band edge (NBE) emission to the deep-level emission was increased about three times by coating the ZnO nanorods with a V2o5 thin film about 10 nm thick. The NBE emission enhancement may be mainly attributed to two sources: the effects of suppression of capturing of carriers by surface states and suppression of visible emission and nonradiative recombination by depletion regions formed in the ZnO cores. In addition, it was found that postannealing of V2O5-coated ZnO nanorods is not desirable, whereas post annealing makes a positive effect on the NBE emission enhancement in uncoated ZnO nanorods. PMID:24757999

Kim, Hyunsu; Jin, Changhyun; Park, Sunghoon; Lee, Wan In; Lee, Chongmu

2014-07-01

403

Improvement of low temperature estimation for MODIS thermal emissive bands by adjusting calibration offset and nonlinear terms  

NASA Astrophysics Data System (ADS)

MODIS is a major instrument for the NASA EOS Terra and Aqua missions, launched in December 1999 and May 2002 respectively. MODIS has 16 thermal emissive bands and they are calibrated using an onboard blackbody (BB) based on a nonlinear second order relationship. While the gains of the MODIS thermal bands are calibrated on a scan-by-scan basis, the offset and non-linear terms are determined either from prelaunch or on-orbit measurements during scheduled BB warm-up and cool-down cycles. A major concern on determination of the offset and non-linear terms from on-orbit BB measurements is that the controlled BB temperature range is relative small compared to the temperature range used in prelaunch tests, which could have impacts on the retrieval of brightness temperatures (BT) well outside the calibration range. In this study, the stability of offset and non-linear terms obtained from BB warm-up/cool-down cycles is presented. Several approaches to derive the on-orbit offset and non-linear terms are used and their impacts on the Earth scene BT estimates are examined. By comparison with BT derived using prelaunch offset and nonlinear terms under the same electronic configuration, it is shown that the current approach of deriving on-orbit offset and nonlinear terms applied in L1B radiance products causes positive BT biases of exceeding 1K at low temperatures for middle- to longwave IR bands. Comparison of MODIS and AIRS (The Atmospheric Infrared Sounder), both on-board Aqua spacecraft, for cold temperature scenes at Antarctica for two long-wave IR bands also indicates that there are temperature-dependent positive BT biases for about the same magnitudes. Results of this study have a significant impact on improving the current approach of setting a 0 and a II used to produce MODIS L1B data products.

Wu, A.; Xiong, X.; Wenny, B.; Moeller, C.; Chen, N.; Chiang, K.

2007-09-01

404

MAPPING H-BAND SCATTERED LIGHT EMISSION IN THE MYSTERIOUS SR21 TRANSITIONAL DISK  

SciTech Connect

We present the first near infrared (NIR) spatially resolved images of the circumstellar transitional disk around SR21. These images were obtained with the Subaru HiCIAO camera, adaptive optics, and the polarized differential imaging technique. We resolve the disk in scattered light at H-band for stellocentric 0.''1 {<=} r {<=} 0.''6 (12 {approx}< r {approx}< 75 AU). We compare our results with previously published spatially resolved 880 {mu}m continuum Submillimeter Array images that show an inner r {approx}< 36 AU cavity in SR21. Radiative transfer models reveal that the large disk depletion factor invoked to explain SR21's sub-mm cavity cannot be 'universal' for all grain sizes. Even significantly more moderate depletions ({delta} = 0.1, 0.01 relative to an undepleted disk) than those that reproduce the sub-mm cavity ({delta} {approx} 10{sup -6}) are inconsistent with our H-band images when they are assumed to carry over to small grains, suggesting that surface grains scattering in the NIR either survive or are generated by whatever mechanism is clearing the disk midplane. In fact, the radial polarized intensity profile of our H-band observations is smooth and steeply inwardly-increasing (r {sup -3}), with no evidence of a break at the 36 AU sub-mm cavity wall. We hypothesize that this profile is dominated by an optically thin disk envelope or atmosphere component. We also discuss the compatibility of our data with the previously postulated existence of a sub-stellar companion to SR21 at r {approx} 10-20 AU, and find that we can neither exclude nor verify this scenario. This study demonstrates the power of multiwavelength imaging of transitional disks to inform modeling efforts, including the debate over precisely what physical mechanism is responsible for clearing these disks of their large midplane grains.

Follette, Katherine B.; Close, Laird [Steward Observatory, The University of Arizona, 933 N Cherry Ave, Tucson, AZ 85721 (United States)] [Steward Observatory, The University of Arizona, 933 N Cherry Ave, Tucson, AZ 85721 (United States); Tamura, Motohide; Hashimoto, Jun; Kwon, Jungmi; Kandori, Ryo [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)] [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Whitney, Barbara [Astronomy Department, University of Wisconsin-Madison, 475 N. Charter Street, Madison, WI 53706 (United States)] [Astronomy Department, University of Wisconsin-Madison, 475 N. Charter Street, Madison, WI 53706 (United States); Grady, Carol [Eureka Scientific, 2452 Delmer, Suite 100, Oakland, CA 96002 (United States)] [Eureka Scientific, 2452 Delmer, Suite 100, Oakland, CA 96002 (United States); Andrews, Sean M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Wisniewski, John [H.L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W Brooks St Norman, OK 73019 (United States)] [H.L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W Brooks St Norman, OK 73019 (United States); Brandt, Timothy D.; Dong, Ruobing [Department of Astrophysical Sciences, Princeton University, NJ 08544 (United States)] [Department of Astrophysical Sciences, Princeton University, NJ 08544 (United States); Mayama, Satoshi [The Center for the Promotion of Integrated Sciences, The Graduate University for Advanced Studies (Sokendai), Shonan International Village, Hayama-cho, Miura-gun, Kanagawa 240-0193 (Japan)] [The Center for the Promotion of Integrated Sciences, The Graduate University for Advanced Studies (Sokendai), Shonan International Village, Hayama-cho, Miura-gun, Kanagawa 240-0193 (Japan); Abe, Lyu [Laboratoire Lagrange, UMR7293, Universite de Nice-Sophia Antipolis, CNRS, Observatoire de la Cote d'Azur, F-06300 Nice (France)] [Laboratoire Lagrange, UMR7293, Universite de Nice-Sophia Antipolis, CNRS, Observatoire de la Cote d'Azur, F-06300 Nice (France); Brandner, Wolfgang; Feldt, Markus [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)] [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Carson, Joseph [Department of Physics and Astronomy, College of Charleston, 58 Coming St., Charleston, SC 29424 (United States)] [Department of Physics and Astronomy, College of Charleston, 58 Coming St., Charleston, SC 29424 (United States); Currie, Thayne [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street M5S 3H4, Toronto Ontario (Canada)] [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street M5S 3H4, Toronto Ontario (Canada); Egner, Sebastian E. [Subaru Telescope, 650 North Aohoku Place, Hilo, HI 96720 (United States)] [Subaru Telescope, 650 North Aohoku Place, Hilo, HI 96720 (United States); Goto, Miwa, E-mail: kfollette@as.arizona.edu [Universitats-Sternwarte Munchen, Ludwig-Maximilians-Universitat, Scheinerstr. 1, D-81679 Munchen (Germany)] [Universitats-Sternwarte Munchen, Ludwig-Maximilians-Universitat, Scheinerstr. 1, D-81679 Munchen (Germany); and others

2013-04-10

405

Mapping H-band Scattered Light Emission in the Mysterious SR21Transitional Disk  

NASA Technical Reports Server (NTRS)

We present the first near infrared (NIR) spatially resolved images of the circumstellar transitional disk around SR21. These images were obtained with the Subaru HiCIAO camera, adaptive optics, and the polarized differential imaging technique. We resolve the disk in scattered light at H-band for stellocentric 0.1 < or approx. r < or approx. 0.6 (12 < or approx. r < or approx. 75AU). We compare our results with previously published spatially resolved 880 micron continuum Submillimeter Array images that show an inner r < or approx. 36AU cavity in SR21. Radiative transfer models reveal that the large disk depletion factor invoked to explain SR21's sub-mm cavity cannot be "universal" for all grain sizes. Even significantly more moderate depletions (delta = 0.1, 0.01 relative to an undepleted disk) than those that reproduce the sub-mm cavity (delta approx. 10(exp -6) are inconsistent with our H-band images when they are assumed to carry over to small grains, suggesting that surface grains scattering in the NIR either survive or are generated by whatever mechanism is clearing the disk midplane. In fact, the radial polarized intensity profile of our H-band observations is smooth and steeply inwardly-increasing (r(sup -3), with no evidence of a break at the 36AU sub-mm cavity wall. We hypothesize that this profile is dominated by an optically thin disk envelope or atmosphere component.We also discuss the compatibility of our data with the previously postulated existence of a sub-stellar companion to SR21 at r approx. 10-20AU, and find that we can neither exclude nor verify this scenario. This study demonstrates the power of multiwavelength imaging of transitional disks to inform modeling efforts, including the debate over precisely what physical mechanism is responsible for clearing these disks of their large midplane grains.

Follette, Katherine B.; Motohide, Tamura; Hashimoto, Jun; Whitney, Barbara; Grady, Carol; Close, Laird; Andrews, Sean M.; Kwon, Jungmi; Wisniewski, John; Brandt, Timothy D.; Mayama, Satoshi; Kandori, Ryo; Dong, Ruobing; Abe, Lyu; Brandner, Wolfgang; Carson, Joseph; Currie, Thayne; Egner, Sebastian E.; Feldt, Markus; Goto, Miwa; Guyon, Olivier.; Hayano, Yutaka; McElwain, Michael W.; Hayashi, Masahiko; Hayashi, Saeko

2013-01-01

406

Annealing effect on the near-band edge emission of ZnO  

NASA Astrophysics Data System (ADS)

ZnO thin films have been grown on the sapphire (?-Al2O3) substrates at the temperature of 250 °C by means of the direct current (DC) magnetron sputtering technique. The crystal structure and surface morphology of the deposited films were investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM). The optical transmission, reflection and luminescence spectra at 300 K were analyzed for both the as-grown and post-annealed ZnO films. Using the ?-modulation method gives the possibility to reveal the main features of the energy band structure and the nature of the radiative transitions causing the ultraviolet (UV) luminescence.

Khomyak, V. V.; Slyotov, M. M.; Shtepliuk, I. I.; Lashkarev, G. V.; Slyotov, O. M.; Marianchuk, P. D.; Kosolovskiy, V. V.

2013-02-01

407

Valence band states and polarized optical emission from nonpolar and semipolar III–nitride quantum well optoelectronic devices  

NASA Astrophysics Data System (ADS)

Nonpolar and semipolar III–nitride quantum wells (QWs) and devices have been extensively studied due to their unique valence band (VB) structure and polarized optical emission. Unlike conventional c-plane oriented III–nitride QWs, the low crystal symmetry and unbalanced biaxial stress in nonpolar and semipolar QWs separates the topmost VBs and gives rise to polarized optical emission. Since the first experimental reports on nonpolar devices, research on this topic has progressed very rapidly and has covered nonpolar m-plane and a-plane QWs and devices as well as semipolar (11\\bar{2}2), (20\\bar{2}1), and (20\\bar{2}\\bar{1}) QWs and devices. Issues such as strain, plane inclination angle (with respect to the c-plane), indium composition, temperature, and their impact on QW VB structure and device performance have been extensively studied. In this paper we review the physical background and theoretical analysis of the VB states and polarized optical emission of nonpolar and semipolar structures and discuss their potential impacts on optoelectronic devices. Experimental results for nonpolar and semipolar light-emitting diodes and laser diodes will be covered along with additional discussions on the potential applications and challenges related to their unique physical properties.

Zhao, Yuji; Farrell, Robert M.; Wu, Yuh-Renn; Speck, James S.

2014-10-01

408

Band Gap Energy of Chalcopyrite Thin Film Solar Cell Absorbers Determined by Soft X-Ray Emission and Absorption Spectroscopy  

SciTech Connect

The chemical and electronic structure of high efficiency chalcopyrite thin film solar cell absorbers significantly differs between the surface and the bulk. While it is widely accepted that the absorber surface exhibits a Cu-poor surface phase with increased band gap (Eg), a direct access to the crucial information of the depth-dependency of Eg is still missing. In this paper, we demonstrate that a combination of x-ray emission and absorption spectroscopy allows a determination of Eg in the surface-near bulk and thus complements the established surface- and bulk-sensitive techniques of Eg determination. As an example, we discuss the determination of Eg for a Cu(In,Ga)Se2 absorber [(1.52 +- 0.20) eV].

Bar, M.; Weinhardt, L.; Pookpanratana, S.; Heske, C.; Nishiwaki, S.; Shafarman, W.; Fuchs, O.; Blum, M.; Yang, W.; Denlinger, J.D.

2008-05-11

409

Spatial variation of the 3.29 and 3.40 micron emission bands within reflection nebulae and the photochemical evolution of methylated polycyclic aromatic hydrocarbons.  

PubMed

Spectra of 3 micrometers emission features have been obtained at several positions within the reflection nebulae NGC 1333 SVS3 and NGC 2023. Strong variations of the relative intensities of the 3.29 micrometers feature and its most prominent satellite band at 3.40 micrometers are found. It is shown that (i) the 3.40 micrometers band is too intense with respect to the 3.29 micrometers band at certain positions to arise from hot band emission alone, (ii) the 3.40 micrometers band can be reasonably well matched by new laboratory spectra of gas-phase polycyclic aromatic hydrocarbons (PAHs) with alkyl (-CH3) side groups, and (iii) the variations in the 3.40 micrometers to 3.29 micrometers band intensity ratios are consistent with the photochemical erosion of alkylated PAHs. We conclude that the 3.40 micrometers emission feature is attributable to -CH3 side groups on PAH molecules. We predict a value of 0.5 for the peak intensity ratio of the 3.40 and 3.29 micrometers emission bands from free PAHs in the diffuse interstellar medium, which would correspond to a proportion of one methyl group for four peripheral hydrogens. We also compare the 3 micrometers spectrum of the proto-planetary nebula IRAS 05341+0852 with the spectrum of the planetary nebula IRAS 21282+5050. We suggest that a photochemical evolution of the initial aliphatic and aromatic hydrocarbon mixture formed in the outflow is responsible for the changes observed in the 3 micrometers emission spectra of these objects. PMID:11538557

Joblin, C; Tielens, A G; Allamandola, L J; Geballe, T R

1996-02-20

410

Spatial Variation of the 3.29 and 3.40 Micron Emission Bands Within Reflection Nebulae and The Photochemical Evolution of Methylated Polycyclic Aromatic Hydrocarbons  

NASA Technical Reports Server (NTRS)

Spectra of 3 microns emission features have been obtained at several positions within the reflection nebulae NGC 1333 SVS3 and NGC 2023. Strong variations of the relative intensities of the 3.29 microns feature and its most prominent satellite band at 3.40 microns are found. It is shown that: (1) the 3.40 microns band is too intense with respect to the 3.29 microns band at certain positions to arise from hot band emission alone, (2) the 3.40 microns band can be reasonably well matched by new laboratory spectra of gas-phase polycyclic aromatic hydrocarbons (PAHs) with alkyl (-CH3) side groups, and (3) the variations in the 3.40 microns to 3.29 microns band intensity ratios are consistent with the photochemical erosion of alkylated PAHs. We conclude that the 3.40 microns emission feature is attributable to -CH3 side groups on PAH molecules. We predict a value of 0.5 for the peak intensity ratio of the 3.40 and 3.29 microns emission bands from free PAHs in the diffuse interstellar medium, which would correspond to a proportion of one methyl group for four peripheral hydrogens. We also compare the 3 microns spectrum of the proto-planetary nebula IRAS 05341 + 0852 with the spectrum of the planetary nebula IRAS 21282 + 5050. We suggest that a photochemical evolution of the initial aliphatic and aromatic hydrocarbon mixture formed in the outflow is responsible for the changes observed in the 3 microns emission spectra of these objects.

Joblin, C.; Tielens, A. G. G. M.; Allamandola, L. J.; Geballe, T. R.

1996-01-01

411

Internal entrainment and the origin of jet-related broad-band emission in Centaurus A  

NASA Astrophysics Data System (ADS)

The dimensions of Fanaroff-Riley class I jets and the stellar densities at galactic centres imply that there will be numerous interactions between the jet and stellar winds. These may give rise to the observed diffuse and `knotty' structure of the jets in the X-ray, and can also mass load the jets. We performed modelling of internal entrainment from stars intercepted by Centaurus A's jet, using stellar evolution- and wind codes. From photometry and a code-synthesized population of 12 Gyr (Z = 0.004), 3 Gyr (Z = 0.008) and 0-60 Myr (Z = 0.02) stars, appropriate for the parent elliptical NGC 5128, the total number of stars in the jet is ˜8 × 108. Our model is energetically capable of producing the observed X-ray emission, even without young stars. We also reproduce the radio through X-ray spectrum of the jet, albeit in a downstream region with distinctly fewer young stars, and recover the mean X-ray spectral index. We derive an internal entrainment rate of ˜2.3 × 10-3 M? yr-1 which implies substantial jet deceleration. Our absolute nucleosynthetic yields for the Asymptotic Giant Branch stellar population in the jet show the highest amounts for 4He, 16O, 12C, 14N and 20Ne. If some of the events at ?55 EeV detected by the Pierre Auger Observatory originate from internal entrainment in Centaurus A, we predict that their composition will be largely intermediate-mass nuclei with 16O, 12C and 14N the key isotopes.

Wykes, Sarka; Hardcastle, Martin J.; Karakas, Amanda I.; Vink, Jorick S.