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

NASA Technical Reports Server (NTRS)

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

2002-01-01

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

Occurrence features of simultaneous H+- and He+-band EMIC emissions in the outer radiation belt

NASA Astrophysics Data System (ADS)

Fu, Song; He, Fengming; Gu, Xudong; Ni, Binbin; Xiang, Zheng; Liu, Jiang

2018-04-01

As an important loss mechanism of radiation belt electrons, electromagnetic ion cyclotron (EMIC) waves show up as three distinct frequency bands below the hydrogen (H+), helium (He+), and oxygen (O+) ion gyrofrequencies. Compared to O+-band EMIC waves, H+- and He+-band emissions generally occur more frequently and result in more efficient scattering removal of <∼5 MeV relativistic electrons. Therefore, knowledge about the occurrence of these two bands is important for understanding the evolution of the relativistic electron population. To evaluate the occurrence pattern and wave properties of H+- and He+-band EMIC waves when they occur concurrently, we investigate 64 events of multi-band EMIC emissions identified from high quality Van Allen Probes wave data. Our quantitative results demonstrate a strong occurrence dependence of the multi-band EMIC emissions on magnetic local time (MLT) and L-shell to mainly concentrate on the dayside region of L = ∼4-6. We also find that the average magnetic field amplitude of H+-band waves is larger than that of He+-band waves only when L < 4.5 and AE∗ < 300 nT, and He+-band emissions are more intense under all other conditions. In contrast to 5 events that have average H+-band amplitude over 2 nT, 19 events exhibit >2 nT He+-band amplitude, indicating that the He+-band waves can be more easily amplified than the H+-band waves under the same circumstances. For simultaneous occurrences of the two EMIC wave bands, their frequencies vary with L-shell and geomagnetic activity: the peak wave frequency of H+-band emissions varies between 0.25 and 0.8 fcp with the average between 0.25 and 0.6 fcp, while that of He+-band emissions varies between 0.03 and 0.23 fcp with the average between 0.05 and 0.15 fcp. These newly observed occurrence features of simultaneous H+- and He+-band EMIC emissions provide improved information to quantify the overall contribution of multi-band EMIC waves to the loss processes of radiation belt electrons.

UNIDENTIFIED INFRARED EMISSION BANDS: PAHs or MAONs?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun Kwok; Yong Zhang, E-mail: sunkwok@hku.hk

2013-07-01

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.

Thermal quenching of the yellow luminescence in GaN

NASA Astrophysics Data System (ADS)

Reshchikov, M. A.; Albarakati, N. M.; Monavarian, M.; Avrutin, V.; Morkoç, H.

2018-04-01

We observed varying thermal quenching behavior of the yellow luminescence band near 2.2 eV in different GaN samples. In spite of the different behavior, the yellow band in all the samples is caused by the same defect—the YL1 center. In conductive n-type GaN, the YL1 band quenches with exponential law, and the Arrhenius plot reveals an ionization energy of ˜0.9 eV for the YL1 center. In semi-insulating GaN, an abrupt and tunable quenching of the YL1 band is observed, where the apparent activation energy in the Arrhenius plot is not related to the ionization energy of the defect. In this case, the ionization energy can be found by analyzing the shift of the characteristic temperature of PL quenching with excitation intensity. We conclude that only one defect, namely, the YL1 center, is responsible for the yellow band in undoped and doped GaN samples grown by different techniques.

Emission characteristics of offshore fishing ships in the Yellow Bo Sea, China.

PubMed

Liu, Yingshuai; Ge, Yunshan; Tan, Jianwei; Fu, Mingliang; Shah, Asad Naeem; Li, Luqiang; Ji, Zhe; Ding, Yan

2018-03-01

Maritime transport has been playing a decisive role in global trade. Its contribution to the air pollution of the sea and coastal areas has been widely recognized. The air pollutant emission inventories of several harbors in China have already been established. However, the emission factors of local ships have not been addressed comprehensively, and thus are lacking from the emission inventories. In this study, on-board emission tests of eight diesel-powered offshore fishing ships were conducted near the coastal region of the northern Yellow Bo Sea fishing ground of Dalian, China. Results show that large amounts of fine particles (<0.5μm, 90%) were found in maneuvering mode, which were about five times higher than those during cruise mode. Emission rates as well as emission factors based on both distance and fuel were determined during the cruise and maneuvering modes (including departure and arrival). Average emission rates and distance-based emission factors of CO, HC and PM were much higher during the maneuvering mode as compared with the cruise mode. However, the average emission rate of Nitrous Oxide (NO x ) was higher during the cruise mode as compared with the maneuvering modes. On the contrary, the average distance-based emission factors of NO x were lower during the cruise mode relative to the maneuvering mode due to the low sailing speed of the latter. Copyright © 2017. Published by Elsevier B.V.

Photoluminescence studies of a perceived white light emission from a monolithic InGaN/GaN quantum well structure

PubMed Central

Ben Sedrine, N.; Esteves, T. C.; Rodrigues, J.; Rino, L.; Correia, M. R.; Sequeira, M. C.; Neves, A. J.; Alves, E.; Bockowski, M.; Edwards, P. R.; O’Donnell, K. P.; Lorenz, K.; Monteiro, T.

2015-01-01

In this work we demonstrate by photoluminescence studies white light emission from a monolithic InGaN/GaN single quantum well structure grown by metal organic chemical vapour deposition. As-grown and thermally annealed samples at high temperature (1000 °C, 1100 °C and 1200 °C) and high pressure (1.1 GPa) were analysed by spectroscopic techniques, and the annealing effect on the photoluminescence is deeply explored. Under laser excitation of 3.8 eV at room temperature, the as-grown structure exhibits two main emission bands: a yellow band peaked at 2.14 eV and a blue band peaked at 2.8 eV resulting in white light perception. Interestingly, the stability of the white light is preserved after annealing at the lowest temperature (1000 °C), but suppressed for higher temperatures due to a deterioration of the blue quantum well emission. Moreover, the control of the yellow/blue bands intensity ratio, responsible for the white colour coordinate temperatures, could be achieved after annealing at 1000 °C. The room temperature white emission is studied as a function of incident power density, and the correlated colour temperature values are found to be in the warm white range: 3260–4000 K. PMID:26336921

Emission coefficients for the OH Meinel band system; calculations and nightglow comparisons

NASA Astrophysics Data System (ADS)

Slanger, T. G.

2016-12-01

The OH Meinel band system is an extensive series of bands that are transitions between the vibrational levels of the X2Π ground-state of the molecule. The exothermicity of the source reaction is sufficient to populate up to OH(v = 9), and in fact the nascent reaction puts most of the product into that level. Subsequently, relaxation of the population to lower levels takes place via collisions with the ambient atmosphere and radiation within the OH(v) manifold. Considerable effort has been spent in determining the emission coefficients of the OH Meinel band system. This emission is a prominent feature of the terrestrial nightglow, and because it is relatively intense, there have been numerous investigations, generally based on ground-based instrumentation. The very exothermic source reaction, H + O3 → OH(v) + O2, results in the production of vibrationally and rotationally hot OH(v), and leads to a great number of OH emission lines, covering a wide spectral range, 500-2000 nm. The full range of energy-accessible OH vibrational levels, up to v = 9, is produced in the reaction, and in this presentation we make the case that it is essential to simultaneously measure as many OH bands as possible, to retrieve the maximum amount of spectroscopic and dynamic information. In order to do so, we must agree on the emission coefficients (A-factors) associated with the individual OH bands, and this determination has presented problems in the past. A major advance in the study of atmospheric OH Meinel band emission took place when astronomical sky spectra were utilized to record all accessible OH bands simultaneously, from Mauna Kea [Cosby and Slanger, 2007]. Subsequently, similar studies were undertaken at the VLT [Noll et al. 2015 a,b], and at the GIANO-TNG [Oliva et al., 2015]. With these intensity-calibrated spectra, it becomes possible to compare the OH optical data with sets of A-factor calculations that have been presented over the years [Mies, 1974; Turnbull and Lowe

Thickness and annealing effects on thermally evaporated InZnO thin films for gas sensors and blue, green and yellow emissive optical devices

NASA Astrophysics Data System (ADS)

Sugumaran, Sathish; Jamlos, Mohd Faizal; Ahmad, Mohd Noor; Bellan, Chandar Shekar; Sivaraj, Manoj

2016-08-01

Indium zinc oxide (InZnO) thin films with thicknesses of 100 nm and 200 nm were deposited on glass plate by thermal evaporation technique. Fourier transform infrared spectra showed a strong metal-oxide bond. X-ray diffraction patterns revealed amorphous nature for as-deposited film whereas polycrystalline structure for annealed films. Scanning electron microscope images showed a uniform distribution of spherical shape grains. Grain size was found to be higher for 200 nm film than 100 nm film. The presence of elements (In, Zn and O) was confirmed from energy dispersive X-ray analysis. Photoluminescence study of 200 nm film showed a blue, blue-green and blue-yellow emission whereas 100 nm film showed a broad green and green-yellow emissions. Both 100 nm and 200 nm films showed good oxygen sensitivity from room temperature to 400 °C. The observed optical and sensor results indicated that the prepared InZnO films are highly potential for room temperature gas sensor and blue, green and yellow emissive opto-electronic devices.

Techniques to minimize adjacent band emissions from Earth Exploration Satellites to protect the Space Research (Category B) Earth Stations in the 8400-8450 MHz band

NASA Technical Reports Server (NTRS)

Wang, Charles C.; Sue, Miles K.; Manshadi, Farzin

2004-01-01

The Earth Exploration Satellites operating in the 8025-8400 MHz band can have strong adjacent band emissions on the8400-8450 MHz band which is allocated for Space Research (Category-B). The unwanted emission may exceed the protection criterion establish by the ITU-R for the protection of the Space Research (Category B) earth stations, i.e., deep-space earth stations. An SFCG Action Item (SF 23/14) was created during the 23rd SFCG meeting to explore technical and operational techniques to reduce the adjacent band emissions. In response to this action item, a study was conducted and results are presented in this document.

Highly Efficient Broadband Yellow Phosphor Based on Zero-Dimensional Tin Mixed-Halide Perovskite.

PubMed

Zhou, Chenkun; Tian, Yu; Yuan, Zhao; Lin, Haoran; Chen, Banghao; Clark, Ronald; Dilbeck, Tristan; Zhou, Yan; Hurley, Joseph; Neu, Jennifer; Besara, Tiglet; Siegrist, Theo; Djurovich, Peter; Ma, Biwu

2017-12-27

Organic-inorganic hybrid metal halide perovskites have emerged as a highly promising class of light emitters, which can be used as phosphors for optically pumped white light-emitting diodes (WLEDs). By controlling the structural dimensionality, metal halide perovskites can exhibit tunable narrow and broadband emissions from the free-exciton and self-trapped excited states, respectively. Here, we report a highly efficient broadband yellow light emitter based on zero-dimensional tin mixed-halide perovskite (C 4 N 2 H 14 Br) 4 SnBr x I 6-x (x = 3). This rare-earth-free ionically bonded crystalline material possesses a perfect host-dopant structure, in which the light-emitting metal halide species (SnBr x I 6-x 4- , x = 3) are completely isolated from each other and embedded in the wide band gap organic matrix composed of C 4 N 2 H 14 Br - . The strongly Stokes-shifted broadband yellow emission that peaked at 582 nm from this phosphor, which is a result of excited state structural reorganization, has an extremely large full width at half-maximum of 126 nm and a high photoluminescence quantum efficiency of ∼85% at room temperature. UV-pumped WLEDs fabricated using this yellow emitter together with a commercial europium-doped barium magnesium aluminate blue phosphor (BaMgAl 10 O 17 :Eu 2+ ) can exhibit high color rendering indexes of up to 85.

Field emission analysis of band bending in donor/acceptor heterojunction

NASA Astrophysics Data System (ADS)

Xing, Yingjie; Li, Shuai; Wang, Guiwei; Zhao, Tianjiao; Zhang, Gengmin

2016-06-01

The donor/acceptor heterojunction plays an important role in organic solar cells. An investigation of band bending in the donor/acceptor heterojunction is helpful in analysis of the charge transport behavior and for the improvement of the device performance. In this work, we report an approach for detection of band bending in a donor/acceptor heterojunction that has been prepared on a small and sharp tungsten tip. In situ field emission measurements are performed after the deposition process, and a linear Fowler-Nordheim plot is obtained from the fresh organic film surface. The thickness-dependent work function is then measured in the layer-by-layer deposited heterojunction. Several different types of heterojunction (zinc phthalocyanine (ZnPc)/C60, copper phthalocyanine (CuPc)/3,4,9,10-perylenetetracarboxylic bisbenzimidazole, and CuPc/C60) are fabricated and analyzed. The different charge transfer directions in the heterojunctions are distinguished by field emission measurements. The calculation method used to determine the band bending is then discussed in detail. A triple layer heterojunction (C60/ZnPc/CuPc) is also analyzed using this method. A small amount of band bending is measured in the outer CuPc layer. This method provides an independent reference method for determination of the band bending in an organic heterojunction that will complement photoemission spectroscopy and current-voltage measurement methods.

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

NASA Technical Reports Server (NTRS)

Nguyen, Truong X.; Ely, Jay J.; Williams, Reuben A.; Koppen, Sandra V.; Salud, Maria Theresa P.

2006-01-01

Radiated emissions in aircraft communication and navigation bands are measured from several active radio frequency identification (RFID) tags. The individual tags are different in design and operations. They may also operate in different frequency bands. The process for measuring the emissions is discussed, and includes tag interrogation, reverberation chamber testing, and instrument settings selection. The measurement results are described and compared against aircraft emission limits. In addition, interference path loss for the cargo bays of passenger aircraft is measured. Cargo bay path loss is more appropriate for RFID tags than passenger cabin path loss. The path loss data are reported for several aircraft radio systems on a Boeing 747 and an Airbus A320.

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

NASA Technical Reports Server (NTRS)

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

2008-01-01

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.

Near-infrared emission bands of TeH and TeD

NASA Astrophysics Data System (ADS)

Fink, E. H.; Setzer, K. D.; Ramsay, D. A.; Vervloet, M.

1989-11-01

High-resolution emission spectra of TeH and TeD have been obtained in the region 4200 to 3600 cm -1 using a Bomem DA3.002 Fourier transform spectrometer. Analyses are given for the 0-0 and 1-1 bands of the X 22Π{1}/{2}-X 12Π{3}/{2} system of TeH and for the 0-0 band of TeD. In addition the 2-0 vibrational overtone bands of 130TeH, 128TeH, and 126TeH are observed and analyzed. Accurate molecular constants are given for the first time.

Laser-induced optical breakdown spectroscopy of polymer materials based on evaluation of molecular emission bands

NASA Astrophysics Data System (ADS)

Trautner, Stefan; Jasik, Juraj; Parigger, Christian G.; Pedarnig, Johannes D.; Spendelhofer, Wolfgang; Lackner, Johannes; Veis, Pavel; Heitz, Johannes

2017-03-01

Laser-induced breakdown spectroscopy (LIBS) for composition analysis of polymer materials results in optical spectra containing atomic and ionic emission lines as well as molecular emission bands. In the present work, the molecular bands are analyzed to obtain spectroscopic information about the plasma state in an effort to quantify the content of different elements in the polymers. Polyethylene (PE) and a rubber material from tire production are investigated employing 157 nm F2 laser and 532 nm Nd:YAG laser ablation in nitrogen and argon gas background or in air. The optical detection reaches from ultraviolet (UV) over the visible (VIS) to the near infrared (NIR) spectral range. In the UV/VIS range, intense molecular emissions, C2 Swan and CN violet bands, are measured with an Echelle spectrometer equipped with an intensified CCD camera. The measured molecular emission spectra can be fitted by vibrational-rotational transitions by open access programs and data sets with good agreement between measured and fitted spectra. The fits allow determining vibrational-rotational temperatures. A comparison to electronic temperatures Te derived earlier from atomic carbon vacuum-UV (VUV) emission lines show differences, which can be related to different locations of the atomic and molecular species in the expanding plasma plume. In the NIR spectral region, we also observe the CN red bands with a conventional CDD Czerny Turner spectrometer. The emission of the three strong atomic sulfur lines between 920 and 925 nm is overlapped by these bands. Fitting of the CN red bands allows a separation of both spectral contributions. This makes a quantitative evaluation of sulfur contents in the start material in the order of 1 wt% feasible.

New Spectral Index for Detecting Wheat Yellow Rust Using Sentinel-2 Multispectral Imagery

PubMed Central

Zheng, Qiong; Huang, Wenjiang; Cui, Ximin; Liu, Linyi

2018-01-01

Yellow rust is one of the most destructive diseases for winter wheat and has led to a significant decrease in winter wheat quality and yield. Identifying and monitoring yellow rust is of great importance for guiding agricultural production over large areas. Compared with traditional crop disease discrimination methods, remote sensing technology has proven to be a useful tool for accomplishing such a task at large scale. This study explores the potential of the Sentinel-2 Multispectral Instrument (MSI), a newly launched satellite with refined spatial resolution and three red-edge bands, for discriminating between yellow rust infection severities (i.e., healthy, slight, and severe) in winter wheat. The corresponding simulative multispectral bands for the Sentinel-2 sensor were calculated by the sensor’s relative spectral response (RSR) function based on the in situ hyperspectral data acquired at the canopy level. Three Sentinel-2 spectral bands, including B4 (Red), B5 (Re1), and B7 (Re3), were found to be sensitive bands using the random forest (RF) method. A new multispectral index, the Red Edge Disease Stress Index (REDSI), which consists of these sensitive bands, was proposed to detect yellow rust infection at different severity levels. The overall identification accuracy for REDSI was 84.1% and the kappa coefficient was 0.76. Moreover, REDSI performed better than other commonly used disease spectral indexes for yellow rust discrimination at the canopy scale. The optimal threshold method was adopted for mapping yellow rust infection at regional scales based on realistic Sentinel-2 multispectral image data to further assess REDSI’s ability for yellow rust detection. The overall accuracy was 85.2% and kappa coefficient was 0.67, which was found through validation against a set of field survey data. This study suggests that the Sentinel-2 MSI has the potential for yellow rust discrimination, and the newly proposed REDSI has great robustness and generalized

New Spectral Index for Detecting Wheat Yellow Rust Using Sentinel-2 Multispectral Imagery.

PubMed

Zheng, Qiong; Huang, Wenjiang; Cui, Ximin; Shi, Yue; Liu, Linyi

2018-03-15

Yellow rust is one of the most destructive diseases for winter wheat and has led to a significant decrease in winter wheat quality and yield. Identifying and monitoring yellow rust is of great importance for guiding agricultural production over large areas. Compared with traditional crop disease discrimination methods, remote sensing technology has proven to be a useful tool for accomplishing such a task at large scale. This study explores the potential of the Sentinel-2 Multispectral Instrument (MSI), a newly launched satellite with refined spatial resolution and three red-edge bands, for discriminating between yellow rust infection severities (i.e., healthy, slight, and severe) in winter wheat. The corresponding simulative multispectral bands for the Sentinel-2 sensor were calculated by the sensor's relative spectral response (RSR) function based on the in situ hyperspectral data acquired at the canopy level. Three Sentinel-2 spectral bands, including B4 (Red), B5 (Re1), and B7 (Re3), were found to be sensitive bands using the random forest (RF) method. A new multispectral index, the Red Edge Disease Stress Index (REDSI), which consists of these sensitive bands, was proposed to detect yellow rust infection at different severity levels. The overall identification accuracy for REDSI was 84.1% and the kappa coefficient was 0.76. Moreover, REDSI performed better than other commonly used disease spectral indexes for yellow rust discrimination at the canopy scale. The optimal threshold method was adopted for mapping yellow rust infection at regional scales based on realistic Sentinel-2 multispectral image data to further assess REDSI's ability for yellow rust detection. The overall accuracy was 85.2% and kappa coefficient was 0.67, which was found through validation against a set of field survey data. This study suggests that the Sentinel-2 MSI has the potential for yellow rust discrimination, and the newly proposed REDSI has great robustness and generalized ability

Determination of microwave vegetation optical depth and water content in the source region of the Yellow River

NASA Astrophysics Data System (ADS)

Liu, R.; Wen, J.; Wang, X.

2017-12-01

In this study, we use dual polarization brightness temperature observational data at the K frequency band collected by the Micro Wave Radiation Imager (MWRI) on board the Fengyun-3B satellite (FY-3B) to improve the τ-ω model by considering the contribution of water bodies in the pixels to radiation in the wetland area of the Yellow River source region. We define a dual polarization slope parameter and express the surface emissivity in the τ-ω model as the sum of the soil and water body emissivity to retrieve the vegetation optical depth (VOD); however, in regions without water body coverage, we still use the τ-ω model to solve for the VOD. By using the field observation data on the vegetation water content (VWC) in the source region of the Yellow River during the summer of 2012, we establish the regression relationship between the VOD and VWC and retrieve the spatial distribution of the VWC. The results indicate that in the entire source region of the Yellow River in 2012, the VOD was in the range of 0.20-1.20 and the VWC was in the range of 0.20 to 1.40, thereby exhibiting a trend of low values in the west and high values in the east. The area with the largest regional variation is along the Yellow River. We compare the results from remote-sensing estimated and ground-measured vegetation water content, and the root-mean-square error is 0.12. The analysis results indicated that by considering the coverage of seasonal wetlands in the source region of the Yellow River, the microwave remote sensing data collected by the FY-3B MWRI can be used to retrieve the vegetation water content in the source region of the Yellow River.

Photonic band edge assisted spontaneous emission enhancement from all Er3+ 1-D photonic band gap structure

NASA Astrophysics Data System (ADS)

Chiasera, A.; Meroni, C.; Varas, S.; Valligatla, S.; Scotognella, F.; Boucher, Y. G.; Lukowiak, A.; Zur, L.; Righini, G. C.; Ferrari, M.

2018-06-01

All Er3+ doped dielectric 1-D Photonic Band Gap Structure was fabricated by rf-sputtering technique. The structure was constituted by of twenty pairs of SiO2/TiO2 alternated layers doped with Er3+ ions. The scanning electron microscopy was used to check the morphology of the structure. Transmission measurements put in evidence the stop band in the range 1500 nm-1950 nm. The photoluminescence measurements were obtained by optically exciting the sample and detecting the emitted light in the 1.5 μm region at different detection angles. Luminescence spectra and luminescence decay curves put in evidence that the presence of the stop band modify the emission features of the Er3+ ions.

Near band edge emission characteristics of sputtered nano-crystalline ZnO films

NASA Astrophysics Data System (ADS)

Kunj, Saurabh; Sreenivas, K.

2016-05-01

Sputtered zinc oxide (ZnO) thin films deposited on unheated glass substrate under different sputtering gas mixtures (Ar+O2) have been investigated using X-ray diffraction and photo luminescence spectroscopy. Earlier reported studies on ZnO films prepared by different techniques exhibit either a sharp/broad near band edge (NBE) emission peak depending on the crystalline quality of the film. In the present study zinc oxide films, grown on unheated substrates, are seen to possess a preferred (002) orientation with a microstructure consisting of clustered nano-sized crystallites. The splitting in the near band edge emission (NBE) into three characteristic peaks is attributed to quantum confinement effect, and is observed specifically under an excitation of 270 nm. Deep level emission (DLE) in the range 400 to 700 nm is not observed indicating absence of deep level radiative defects.

SEARCHING FOR NEW YELLOW SYMBIOTIC STARS: POSITIVE IDENTIFICATION OF StHα63

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baella, N. O.; Pereira, C. B.; Alvarez-Candal, A.

2016-04-15

Yellow symbiotic stars are useful targets for probing whether mass transfer has happened in their binary systems. However, the number of known yellow symbiotic stars is very scarce. We report spectroscopic observations of five candidate yellow symbiotic stars that were selected by their positions in the 2MASS (J − H) versus (H − K{sub s}) diagram and which were included in some emission-line catalogs. Among the five candidates, only StHα63 is identified as a new yellow symbiotic star because of its spectrum and its position in the [TiO]{sub 1}–[TiO]{sub 2} diagram, which indicates a K4–K6 spectral type. In addition, themore » derived electron density (∼10{sup 8.4} cm{sup −3}) and several emission-line intensity ratios provide further support for that classification. The other four candidates are rejected as symbiotic stars because three of them actually do not show emission lines and the fourth one only Balmer emission lines. We also found that the WISE W3–W4 index clearly separates normal K-giants from yellow symbiotic stars and therefore can be used as an additional tool for selecting candidate yellow symbiotic stars.« less

Multicolor emission from intermediate band semiconductor ZnO 1-xSe x

DOE Office of Scientific and Technical Information (OSTI.GOV)

Welna, M.; Baranowski, M.; Linhart, W. M.

Photoluminescence and photomodulated reflectivity measurements of ZnOSe alloys are used to demonstrate a splitting of the valence band due to the band anticrossing interaction between localized Se states and the extended valence band states of the host ZnO matrix. A strong multiband emission associated with optical transitions from the conduction band to lower E - and upper E + valence subbands has been observed at room temperature. The composition dependence of the optical transition energies is well explained by the electronic band structure calculated using the kp method combined with the band anticrossing model. The observation of the multiband emissionmore » is possible because of relatively long recombination lifetimes. Longer than 1 ns lifetimes for holes photoexcited to the lower valence subband offer a potential of using the alloy as an intermediate band semiconductor for solar power conversion applications.« less

Multicolor emission from intermediate band semiconductor ZnO 1-xSe x

DOE PAGES

Welna, M.; Baranowski, M.; Linhart, W. M.; ...

2017-03-13

Photoluminescence and photomodulated reflectivity measurements of ZnOSe alloys are used to demonstrate a splitting of the valence band due to the band anticrossing interaction between localized Se states and the extended valence band states of the host ZnO matrix. A strong multiband emission associated with optical transitions from the conduction band to lower E - and upper E + valence subbands has been observed at room temperature. The composition dependence of the optical transition energies is well explained by the electronic band structure calculated using the kp method combined with the band anticrossing model. The observation of the multiband emissionmore » is possible because of relatively long recombination lifetimes. Longer than 1 ns lifetimes for holes photoexcited to the lower valence subband offer a potential of using the alloy as an intermediate band semiconductor for solar power conversion applications.« less

Chemical trends of the luminescence in wide band gap II 1-xMn xVI semimagnetic semiconductors

NASA Astrophysics Data System (ADS)

Benecke, C.; Busse, W.; Gumlich, H.-E.

1990-04-01

Time resolved emission and excitation spectroscopy is used to investigate the Mn correlated luminescence in wide band gap II-VI compounds, i.e. Zn 1-xMn xS, Cd 1-xMn xSe, Zn 1-xMn xTe and Cd 1-xMn xTe. Additional Information has been obtained with CdxZnyMnzTe( x+ y+ z=1) in checking the luminescence by variation of the ratio of the cations Cd and Zn. Generally speaking, at least two distinct emissions bands can be observed for each II 1- xMn xVI compound. One emissions band is attributed to the internal transition 4T 1(G)→ 6A 1(S) of the 3d 5 electron of the Mn 2+ on regular metal sites with energies of about ≈2 eV. The other emission band is found to occur in the near infrared range of about ≈1.3 eV. This emission band is tentatively interpreted as a transition of Mn 2+ ions on interstitial sites or in small Mn chalcogenide clusters, both interpretations assuming cubic symmetry. This model is supported by the existence of low energy excitation bands and by the great similarity of the shape of the two emission bands which lead to comparable Huang-Rhys factors and effective phonon energies. Also the established trend in the experimental data of the II-VI compounds under consideration confirm this interpretation. For both the IR and the yellow Mn 2+ center, the Racah parameters B and C and the crystal field parameter Dq are determined on the basis of experimental data. As a result, the energy of both the emission and the excitation bands is predominantly determined by the sorrounding anions. These bands shift to higher energies when the anions are changed in the fixed order: Te→Se→S. Regularly, there is also a spectral shift when Zn is replaced by Cd, which is smaller than the shift due to the variation of onions.

Monitoring luminous yellow massive stars in M 33: new yellow hypergiant candidates

NASA Astrophysics Data System (ADS)

Kourniotis, M.; Bonanos, A. Z.; Yuan, W.; Macri, L. M.; Garcia-Alvarez, D.; Lee, C.-H.

2017-05-01

Context. The evolution of massive stars surviving the red supergiant (RSG) stage remains unexplored due to the rarity of such objects. The yellow hypergiants (YHGs) appear to be the warm counterparts of post-RSG classes located near the Humphreys-Davidson upper luminosity limit, which are characterized by atmospheric instability and high mass-loss rates. Aims: We aim to increase the number of YHGs in M 33 and thus to contribute to a better understanding of the pre-supernova evolution of massive stars. Methods: Optical spectroscopy of five dust-enshrouded yellow supergiants (YSGs) selected from mid-IR criteria was obtained with the goal of detecting evidence of extensive atmospheres. We also analyzed BVIc photometry for 21 of the most luminous YSGs in M 33 spanning approximately nine years to identify changes in the spectral type that are expected based on the few well-studied YHGs. To explore the properties of circumstellar dust, we performed spectral energy distribution fitting of multi-band photometry of the 21 YSGs. We additionally conducted K-band spectroscopy of the YHG candidate B324 in search of processed ejected material. Results: We find three luminous YSGs in our sample, stars 2, 6 and 13, with log L/L⊙ ≳ 5.35 to be YHG candidates, as they are surrounded by hot dust and are enshrouded within extended, cold dusty envelopes. Our spectroscopy of star 2 shows emission of more than one Hα component, as well as emission of Ca II and [N II], implying an extended atmospheric structure. In addition, the long-term monitoring of the star reveals a dimming in the visual light curve of amplitude larger than 0.5 mag that caused an apparent drop in the temperature that exceeded 500 K. We suggest the observed variability to be analogous to that of the Galactic YHG ρ Cas. We further support the post-RSG classification of N125093 and B324 instead of being LBVs in outburst. Five less luminous YSGs are suggested as post-RSG candidates showing evidence of hot or

Nitric oxide excited under auroral conditions: Excited state densities and band emissions

NASA Astrophysics Data System (ADS)

Cartwright, D. C.; Brunger, M. J.; Campbell, L.; Mojarrabi, B.; Teubner, P. J. O.

2000-09-01

Electron impact excitation of vibrational levels in the ground electronic state and nine excited electronic states in NO has been simulated for an IBC II aurora (i.e., ˜10 kR in 3914 Å radiation) in order to predict NO excited state number densities and band emission intensities. New integral electron impact excitation cross sections for NO were combined with a measured IBC II auroral secondary electron distribution, and the vibrational populations of 10 NO electronic states were determined under conditions of statistical equilibrium. This model predicts an extended vibrational distribution in the NO ground electronic state produced by radiative cascade from the seven higher-lying doublet excited electronic states populated by electron impact. In addition to significant energy storage in vibrational excitation of the ground electronic state, both the a 4Π and L2 Φ excited electronic states are predicted to have relatively high number densities because they are only weakly connected to lower electronic states by radiative decay. Fundamental mode radiative transitions involving the lowest nine excited vibrational levels in the ground electronic state are predicted to produce infrared (IR) radiation from 5.33 to 6.05 μm with greater intensity than any single NO electronic emission band. Fundamental mode radiative transitions within the a 4Π electronic state, in the 10.08-11.37 μm region, are predicted to have IR intensities comparable to individual electronic emission bands in the Heath and ɛ band systems. Results from this model quantitatively predict the vibrational quantum number dependence of the NO IR measurements of Espy et al. [1988].

Sub-band gap photo-enhanced secondary electron emission from high-purity single-crystal chemical-vapor-deposited diamond

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yater, J. E., E-mail: joan.yater@nrl.navy.mil; Shaw, J. L.; Pate, B. B.

2016-02-07

Secondary-electron-emission (SEE) current measured from high-purity, single-crystal (100) chemical-vapor-deposited diamond is found to increase when sub-band gap (3.06 eV) photons are incident on the hydrogenated surface. Although the light does not produce photoemission directly, the SEE current increases by more than a factor of 2 before saturating with increasing laser power. In energy distribution curves (EDCs), the emission peak shows a corresponding increase in intensity with increasing laser power. However, the emission-onset energy in the EDCs remains constant, indicating that the bands are pinned at the surface. On the other hand, changes are observed on the high-energy side of the distributionmore » as the laser power increases, with a well-defined shoulder becoming more pronounced. From an analysis of this feature in the EDCs, it is deduced that upward band bending is present in the near-surface region during the SEE measurements and this band bending suppresses the SEE yield. However, sub-band gap photon illumination reduces the band bending and thereby increases the SEE current. Because the bands are pinned at the surface, we conclude that the changes in the band levels occur below the surface in the electron transport region. Sample heating produces similar effects as observed with sub-band gap photon illumination, namely, an increase in SEE current and a reduction in band bending. However, the upward band bending is not fully removed by either increasing laser power or temperature, and a minimum band bending of ∼0.8 eV is established in both cases. The sub-band gap photo-excitation mechanism is under further investigation, although it appears likely at present that defect or gap states play a role in the photo-enhanced SEE process. In the meantime, the study demonstrates the ability of visible light to modify the electronic properties of diamond and enhance the emission capabilities, which may have potential impact for diamond-based vacuum

2D XANES-XEOL mapping: observation of enhanced band gap emission from ZnO nanowire arrays

NASA Astrophysics Data System (ADS)

Wang, Zhiqiang; Guo, Xiaoxuan; Sham, Tsun-Kong

2014-05-01

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

Searching for New Yellow Symbiotic Stars: Positive Identification of StHα63

NASA Astrophysics Data System (ADS)

Baella, N. O.; Pereira, C. B.; Miranda, L. F.; Alvarez-Candal, A.

2016-04-01

Yellow symbiotic stars are useful targets for probing whether mass transfer has happened in their binary systems. However, the number of known yellow symbiotic stars is very scarce. We report spectroscopic observations of five candidate yellow symbiotic stars that were selected by their positions in the 2MASS (J - H) versus (H - Ks) diagram and which were included in some emission-line catalogs. Among the five candidates, only StHα63 is identified as a new yellow symbiotic star because of its spectrum and its position in the [TiO]1-[TiO]2 diagram, which indicates a K4-K6 spectral type. In addition, the derived electron density (˜108.4 cm-3) and several emission-line intensity ratios provide further support for that classification. The other four candidates are rejected as symbiotic stars because three of them actually do not show emission lines and the fourth one only Balmer emission lines. We also found that the WISE W3-W4 index clearly separates normal K-giants from yellow symbiotic stars and therefore can be used as an additional tool for selecting candidate yellow symbiotic stars. Based on observations collected at the Centro Astronómico Hispano-Alemán, Calar Alto, jointly operated by the Max-Planck-Institut für Astronomie (Heidelberg) and the Instituto de Astrofísica de Andalucía (CSIC), and at the 4.1 m telescope at Cerro Pachón Observatory, Chile.

Use of IRI to Model the Effect of Ionosphere Emission on Earth Remote Sensing at L-Band

NASA Technical Reports Server (NTRS)

Abraham, Saji; LeVine, David M.

2004-01-01

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.

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

NASA Technical Reports Server (NTRS)

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

1985-01-01

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.

Investigation of narrow-band thermal emission from intersubband transitions in quantum wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Zoysa, M.; Hakubi Center, Kyoto University, Yoshida, Kyoto 606-8501; Asano, T.

2015-09-14

We investigate thermal emission from n-doped GaAs/AlGaAs quantum wells (QWs). Emission peaks with Lorentzian shapes (linewidth 11∼19 meV) that reflect transitions between the first and second conduction subbands are observed in the mid-infrared range. It is demonstrated that the emission characteristics can be tuned by modifying the QW parameters. The peak emissivity is increased from 0.3 to 0.9 by modifying the doping density, and the peak wavelength is tuned from 6 to 10 μm by changing the well width. The obtained results are useful for the design of narrow-band thermal emitters.

Interpreting Methanol v(sub 2)-Band Emission in Comets Using Empirical Fluorescence g-Factors

NASA Technical Reports Server (NTRS)

DiSanti, Michael; Villanueva, G. L.; Bonev, B. P.; Mumma, M. J.; Paganini, L.; Gibb, E. L.; Magee-Sauer, K.

2011-01-01

For many years we have been developing the ability, through high-resolution spectroscopy targeting ro-vibrational emission in the approximately 3 - 5 micrometer region, to quantify a suite of (approximately 10) parent volatiles in comets using quantum mechanical fluorescence models. Our efforts are ongoing and our latest includes methanol (CH3OH). This is unique among traditionally targeted species in having lacked sufficiently robust models for its symmetric (v(sub 3) band) and asymmetric (v(sub 2) and v(sub 9) bands) C-H3 stretching modes, required to provide accurate predicted intensities for individual spectral lines and hence rotational temperatures and production rates. This has provided the driver for undertaking a detailed empirical study of line intensities, and has led to substantial progress regarding our ability to interpret CH3OH in comets. The present study concentrates on the spectral region from approximately 2970 - 3010 per centimeter (3.367 - 3.322 micrometer), which is dominated by emission in the (v(sub 7) band of C2H6 and the v(sub 2) band of CH3OH, with minor contributions from CH3OH (v(sub 9) band), CH4 (v(sub 3)), and OH prompt emissions (v(sub 1) and v(sub 2)- v(sub 1)). Based on laboratory jet-cooled spectra (at a rotational temperature near 20 K)[1], we incorporated approximately 100 lines of the CH3OH v(sub 2) band, having known frequencies and lower state rotational energies, into our model. Line intensities were determined through comparison with several comets we observed with NIRSPEC at Keck 2, after removal of continuum and additional molecular emissions and correcting for atmospheric extinction. In addition to the above spectral region, NIRSPEC allows simultaneous sampling of the CH3OH v(sub 3) band (centered at 2844 per centimeter, or 3.516 micrometers and several hot bands of H2O in the approximately 2.85 - 2.9 micrometer region, at a nominal spectral resolving power of approximately 25,000 [2]. Empirical g-factors for v(sub 2

PROBING THE IONIZATION STATES OF POLYCYCLIC AROMATIC HYDROCARBONS VIA THE 15–20 μm EMISSION BANDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shannon, M. J.; Stock, D. J.; Peeters, E., E-mail: mshann3@uwo.ca

2015-10-01

We report new correlations between ratios of band intensities of the 15–20 μm emission bands of polycyclic aromatic hydrocarbons (PAHs) in a sample of 57 sources observed with the Spitzer/Infrared Spectrograph. This sample includes Large Magellanic Cloud point sources from the SAGE-Spec survey, nearby galaxies from the Spitzer Infrared Nearby Galaxies Survey survey, two Galactic interstellar medium cirrus sources, and the spectral maps of the Galactic reflection nebulae NGC 2023 and NGC 7023. We find that the 16.4, 17.4, and 17.8 μm band intensities are inter-correlated in all environments. In NGC 2023 and NGC 7023 these bands also correlate withmore » the 11.0 and 12.7 μm band intensities. The 15.8 μm band correlates only with the 15–18 μm plateau and the 11.2 μm emission. We examine the spatial morphology of these bands and introduce radial cuts. We find that these bands can be spatially organized into three sets: the 12.7, 16.4, and 17.8 μm bands; the 11.2, 15.8 μm bands and the 15–18 μm plateau; and the 11.0 and 17.4 μm bands. We also find that the spatial distribution of the 12.7, 16.4, and 17.8 μm bands can be reconstructed by averaging the spatial distributions of the cationic 11.0 μm and neutral 11.2 μm bands. We conclude that the 17.4 μm band is dominated by cations, the 15.8 μm band by neutral species, and the 12.7, 16.4, and 17.8 μm bands by a combination of the two. These results highlight the importance of PAH ionization for spatially differentiating sub-populations by their 15–20 μm emission variability.« less

Pressure-induced emission band separation of the hybridized local and charge transfer excited state in a TPE-based crystal.

PubMed

Liu, Xuedan; Li, Aisen; Xu, Weiqing; Ma, Zhiyong; Jia, Xinru

2018-05-08

We herein report a newly synthesized simple molecule, named TPE[double bond, length as m-dash]C4, with twisted D-A structure. TPE[double bond, length as m-dash]C4 showed two intrinsic emission bands ascribed to the locally excited (LE) state and the intramolecular charge transfer (ICT) state, respectively. In the crystal state, the LE emission band is usually observed. However, by applying hydrostatic pressure to the powder sample and the single crystal sample of TPE[double bond, length as m-dash]C4, dual-fluorescence (445 nm and 532 nm) was emerged under high pressure, owing to the pressure-induced emission band separation of the hybridized local and charge transfer excited state (HLCT). It is found that the emission of TPE[double bond, length as m-dash]C4 is generally determined by the ratio of the LE state to the ICT state. The ICT emission band is much more sensitive to the external pressure than the LE emission band. The HLCT state leads to a sample with different responsiveness to grinding and hydrostatic pressure. This study is of significance in the molecular design of such D-A type molecules and in the control of photoluminescence features by molecular structure. Such results are expected to pave a new way to further understand the relationship between the D-A molecular structure and stimuli-responsive properties.

Enhanced Spontaneous Emission of Bloch Oscillation Radiation from a Single Energy Band

DTIC Science & Technology

2006-06-30

ignore interband tunneling , spon- taneous photon emission occurs as the Bloch electron inter- acts with the quantum radiation field; the emission occurs... interband coupling 17 and electron intraband scattering are ignored. Therefore, the quantum dynamics is described by the time-dependent Schrödinger...single band “n0” of a periodic crystal with energy n0K; the ef- fects of interband coupling15 and electron intraband scatter- ing are ignored

VLF-emissions from ring current electrons. An interpretation of the band of missing emissions

NASA Technical Reports Server (NTRS)

Maeda, K.; Smith, P. H.; Anderson, R. R.

1976-01-01

VLF-emissions associated with the enhancement of ring current electrons during magnetic storms and substorms which were detected by the equatorially orbiting S-A satellite (Explorer 45) are described. The emissions observed near the geomagnetic equator consist of essentially two frequency regimes, i.e., one above the electron gyrofrequency, f sub H at the equator and the other below f sub H. This is indicated as a part of the wide-band data obtained during the main phase of the December 17, 1971 magnetic storm. The upper figure is the ac-magnetic field data measured by the search-coil magnetometer with the upper cutoff of 3kHz and the lower figure is the ac-electric field data obtained by the electric field sensor with the upper cutoff of 10kHz. These figures show the time sequence of the observed emissions along the inbound orbit (No. 101) of the satellite as f sub H changes approximately from 3 kHz at 20 UT to 6 kHz at 21 UT. The emissions above f sub H are electrostatic mode, which peak near the frequencies of (n + 1/2) f sub H where n is positive integer, and sometimes emissions up to n = 10 are observed. The emissions below f sub H are whistler mode, which have a conspicuous gap along exactly half electron gyrofrequency, f sub H/2.

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

NASA Technical Reports Server (NTRS)

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

1992-01-01

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.

Facile solution-precipitation assisted synthesis and luminescence property of greenish-yellow emitting Ca{sub 6}Ba(PO{sub 4}){sub 4}O:Eu{sup 2+} phosphor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ji, Haipeng; Huang, Zhaohui, E-mail: huang118@cugb.edu.cn; Xia, Zhiguo, E-mail: xiazg@ustb.edu.cn

2016-03-15

Highlights: • Ca{sub 6}Ba(PO{sub 4}){sub 4}O:Eu{sup 2+} phosphor was prepared by the solution-precipitation assisted route. • The phosphors have satisfactory smooth grain surface and particle size. • It shows greenish-yellow color emission (maximum at 540 nm) upon blue light excitation. • Eu{sup 2+} is coordinated with isolated oxygen atoms and those from PO{sub 4} polyhedra. - Abstract: Greenish-yellow emitting microcrystalline Ca{sub 6}Ba(PO{sub 4}){sub 4}O:Eu{sup 2+} phosphor was successfully prepared by a solution-precipitation assisted high temperature reaction method. Phase structure, morphology and/or luminescence properties of the precursor and the as-prepared phosphors were characterized. The phase-pure Ca{sub 6}Ba(PO{sub 4}){sub 4}O:Eu{sup 2+} phosphorsmore » were obtained with smooth grain surface and particle size of 2–8 μm. Ca{sub 6}Ba(PO{sub 4}){sub 4}O:Eu{sup 2+} exhibits bright greenish-yellow color emission with its maximum at 540 nm upon UV-blue light excitation. The maximum position of the broad emission band is independent on the calcination temperature. The emission intensity increases with increasing calcination temperature due to improved crystallinity. Besides, the presence of two Eu{sup 2+} emission centers in the Ca{sub 6}Ba(PO{sub 4}){sub 4}O crystal lattice was confirmed and the coordination effects are considered concerning the roles of isolated O atoms and those from the PO{sub 4} tetrahedra.« less

Carbon Emission from Tibet Plateau Rivers: a Case Study of the Yellow River Headwater Region

NASA Astrophysics Data System (ADS)

Lu, X. X.; Yang, X.; Tian, M. Y.; Su, Y. R.; Ran, L.; Hu, H. Z.; Yu, R. H.

2017-12-01

Global warming will have major impacts on the high-altitude environments, including glacier retreats and permafrost thawing. Permafrost soils contain enormous amounts of organic carbon, which could act as a positive feedback to global climate change due to enhanced respiration rates with warming. Study on riverine sediment and carbon fluxes from permafrost thawing and glacial retreat at high latitudes can help to identify the potential hazards of carbon emissions and provide scientific references for formulating climate adaptation strategy. The headwater region of the Yellow River, located in the north eastern Tibetan Plateau, retains a huge amount of organic carbon stored in the widely distributed meadow and steppe soils, which has been and will be affected by climate change. For example, carbon storage in the Ruoergai (Zoige) wetlands surrounded by mountain glaciers and permafrost is estimated at 23.2 Gt, representing a very high percentage of the soil carbon in the entire Tibet Plateau. Global warming will have far-reaching impacts on riverine sediment and carbon fluxes in this region. However, the amount of riverine carbon released by glacier retreat and permafrost thawing has not been well studied in this region. This talk will report our results obtained from 4 rounds of field campaign in the headwater region of the Yellow River, with a focus of the river and stream systems in the Ruoergai peatland and the Anyemaqen glacier. Our preliminary results indicated that riverine carbon emission from the headwater region was much higher than our previous report estimated from water chemistry data. With increase in temperature the rivers in Himalayas and Tibet Plateau are potential carbon source areas.

Dayglow emissions of the O2 Herzberg bands and the Rayleigh backscattered spectrum of the earth

NASA Technical Reports Server (NTRS)

Frederick, J. E.; Abrams, R. B.

1982-01-01

It is pointed out that numerous fluorescent emissions from the Herzberg bands of molecular oxygen lie in the spectral region 242-300 nm. This coincides with the wavelength range used by orbiting spectrometers that observe the Rayleigh backscattered spectrum of the earth for the purpose of monitoring the vertical distribution of stratospheric ozone. Model calculations suggest that Herzberg band emissions in the dayglow could provide significant contamination of the ozone measurements if the quenching rate of O2(A3Sigma) is sufficiently small. It is noted that this is especially true near 255 nm, where the most intense fluorescent emissions relative to the Rayleigh scattered signal are located and where past satellite measurements have shown a persistent excess radiance above that expected for a pure ozone absorbing and molecular scattering atmosphere. Very small quenching rates, however, are adequate to reduce the dayglow emission to negligible levels. Noting that available laboratory data have not definitely established the quenching on the rate of O2(A3Sigma) as a function of vibration level, it is emphasized that such information is required before the Herzberg band contributions can be evaluated with confidence.

The development of Ce3+-activated (Gd,Lu)3Al5O12 garnet solid solutions as efficient yellow-emitting phosphors

NASA Astrophysics Data System (ADS)

Li, Jinkai; Li, Ji-Guang; Liu, Shaohong; Li, Xiaodong; Sun, Xudong; Sakka, Yoshio

2013-10-01

Ce3+-activated Gd3Al5O12 garnet, effectively stabilized by Lu3+ doping, has been developed for new yellow-emitting phosphors. The powder processing of [(Gd1-xLux)1-yCey]3Al5O12 solid solutions was achieved through precursor synthesis via carbonate precipitation, followed by annealing. The resultant (Gd,Lu)AG:Ce3+ phosphor particles exhibit typical yellow emission at ˜570 nm (5d-4f transition of Ce3+) upon blue-light excitation at ˜457 nm (the 2F5/2-5d transition of Ce3+). The quenching concentration of Ce3+ was determined to be ˜1.0 at% (y = 0.01) and the quenching mechanism was suggested to be driven by exchange interactions. The best luminescent [(Gd0.9Lu0.1)0.99Ce0.01]AG phosphor is comparative to the well-known YAG:Ce3+ in emission intensity but has a substantially red-shifted emission band that is desired for warm-white lighting. The effects of processing temperature (1000-1500 °C) on the spectroscopic properties of the phosphors, especially those of Lu3+/Ce3+, were thoroughly investigated and discussed from the centroid position and crystal field splitting of the Ce3+ 5d energy levels.

Hydrogenation of polycyclic aromatic hydrocarbons as a factor affecting the cosmic 6.2 micron emission band

NASA Technical Reports Server (NTRS)

Beegle, L. W.; Wdowiak, T. J.; Harrison, J. G.

2001-01-01

While many of the characteristics of the cosmic unidentified infrared (UIR) emission bands observed for interstellar and circumstellar sources within the Milky Way and other galaxies, can be best attributed to vibrational modes of the variants of the molecular family known as polycyclic aromatic hydrocarbons (PAH), there are open questions that need to be resolved. Among them is the observed strength of the 6.2 micron (1600 cm(-1)) band relative to other strong bands, and the generally low strength for measurements in the laboratory of the 1600 cm(-1) skeletal vibration band of many specific neutral PAH molecules. Also, experiments involving laser excitation of some gas phase neutral PAH species while producing long lifetime state emission in the 3.3 micron (3000 cm(-1)) spectral region, do not result in significant 6.2 micron (1600 cm(-1)) emission. A potentially important variant of the neutral PAH species, namely hydrogenated-PAH (H(N)-PAH) which exhibit intriguing spectral correlation with interstellar and circumstellar infrared emission and the 2175 A extinction feature, may be a factor affecting the strength of 6.2 micron emission. These species are hybrids of aromatic and cycloalkane structures. Laboratory infrared absorption spectroscopy augmented by density function theory (DFT) computations of selected partially hydrogenated-PAH molecules, demonstrates enhanced 6.2 micron (1600 cm(-1)) region skeletal vibration mode strength for these molecules relative to the normal PAH form. This along with other factors such as ionization or the incorporation of nitrogen or oxygen atoms could be a reason for the strength of the cosmic 6.2 micron (1600 cm(-1)) feature.

Determination of sunset yellow in soft drinks based on fluorescence quenching of carbon dots

NASA Astrophysics Data System (ADS)

Yuan, Yusheng; Zhao, Xin; Qiao, Man; Zhu, Jinghui; Liu, Shaopu; Yang, Jidong; Hu, Xiaoli

2016-10-01

Fluorescent carbon dots was prepared by heating N-(2-hydroxyethyl)ethylene diaminetriacetic acid in air. The carbon dots were not only highly soluble in water but also uniform in size, and possessed strong blue fluorescence and excitation wavelength-dependent emission properties with the maximum excitation and emission wavelength at 366 nm and 423 nm, respectively. Food colorant sunset yellow whose excitation and emission wavelength at 303 nm and 430 nm could selectively quench the fluorescence of carbon dots, efficient fluorescent resonance energy transfer between the carbon dots and sunset yellow is achieved. This was exploited to design a method for the determination of sunset yellow in the concentration range from 0.3 to 8.0 μmol L- 1, with a limit of detection (3 σ/k) of 79.6 nmol L- 1. Furthermore the fluorimetric detection method was established and validated for sunset yellow in soft drinks samples with satisfactory results.

Imaging of the PAH Emission Bands in the Orion Bar

NASA Technical Reports Server (NTRS)

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

1994-01-01

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.

Multiyear On-orbit Calibration and Performance of Terra MODIS Thermal Emissive Bands

NASA Technical Reports Server (NTRS)

Xiong, Xiaoxiong; Chiang, Kwo-Fu; Wu, Aisheng; Barnes, William; Guenther, Bruce; Salomonson, Vincent

2007-01-01

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

Fabrication of a white electroluminescent device based on bilayered yellow and blue quantum dots

NASA Astrophysics Data System (ADS)

Kim, Jong-Hoon; Lee, Ki-Heon; Kang, Hee-Don; Park, Byoungnam; Hwang, Jun Yeon; Jang, Ho Seong; Do, Young Rag; Yang, Heesun

2015-03-01

-In-S (CIS)/ZnS is used for the formation of the emitting layer (EML) of a multilayered QLED. First, the QLED consisting of a single EML randomly mixed with two QDs is fabricated, however, its EL is dominated by blue emission with the contribution of yellow emission substantially weaker. Thus, another EML configuration is devised in the form of a QD bilayer with two stacking sequences of CdZnS/ZnS//CIS/ZnS QD and vice versa. The QLED with the former stacking sequence shows an overwhelming contribution of blue EL, similar to the mixed QD EML-based device. Upon applying the oppositely stacked QD bilayer of CIS/ZnS//CdZnS/ZnS, however, a bicolored white EL can be successfully achieved by means of the effective extension of the radiative excitonic recombination zone throughout both QD EML regions. Such QD EML configuration-dependent EL results, which are discussed primarily using the proposed device energy level diagram, strongly suggest that the positional design of individual QD emitters is a critical factor for the realization of multicolored, white emissive devices. Electronic supplementary information (ESI) available: Detailed description of synthesis of CdZnS/ZnS, CIS/ZnS QDs and ZnO NPs; TEM images of CdZnS/ZnS and CIS/ZnS QDs; voltage-dependent luminance (CE variations of blue CdZnS/ZnS and yellow CIS/ZnS monochromatic QLEDs; EL spectra and energy band diagram of bilayered QD EML-based QLED with a stacking sequence of CdZnS/ZnS//CIS/ZnS QD; normalized EL spectra of CIS/ZnS//CdZnS/ZnS QD-bilayered QLEDs; comparison of current density of monochromatic QLEDs and bicolored white QLEDs; and voltage-dependent luminance (CE variations of CIS/ZnS QLED fabricated through 150 °C-EML baking. See DOI: 10.1039/c5nr00426h

Unique light-induced degradation in yellow-emitting K₂SiF₆:Mn²⁺ phosphor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oyama, Takuya; Adachi, Sadao, E-mail: adachi@el.gunma-u.ac.jp

2014-10-07

Photo-induced luminescence intensity degradation in yellow-emitting K₂SiF₆:Mn²⁺ phosphor is studied using x-ray diffraction measurement, photoluminescence (PL) analysis, PL excitation (PLE) spectroscopy, PL decay analysis, and electron spin resonance (ESR) measurement. The yellow-emitting K₂SiF₆:Mn²⁺ phosphor exhibits remarkable degradation in the PL intensity under Xe lamp exposure. Coherent laser irradiation also induces degradation and its degree is in the order of He–Cd (λ = 325 nm) > Ar⁺ (488 nm) > He–Ne laser (632.8 nm). The degradation mechanism is proposed to be due to change in the valence state of manganese ions from Mn²⁺ to Mn³⁺ by the photooxidation (Mn²⁺ → Mn³⁺)more » or disproportionation reaction (2Mn²⁺ → Mn⁺ + Mn³⁺). The ESR measurement confirms the decreased Mn²⁺ spin density in the sample exposed with Xe lamp. The PLE spectrum suggests that the excitation of Mn³⁺ ions occurs through energy transfer upon absorption of exciting radiation by the Mn²⁺ ions. Thermal annealing of the degraded samples at ≥200 °C causes a blueshift in the PL emission band with an appearance of the Mn⁴⁺-related sharp red emission lines.« less

New yellow Ba 0.93Eu 0.07Al 2O 4 phosphor for warm-white light-emitting diodes through single-emitting-center conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xufan; Budai, John D.; Liu, Feng

2013-01-01

Phosphor-converted white light-emitting diodes for indoor illumination need to be warm-white (i.e., correlated color temperature <4000 K) with good color rendition (i.e., color rendering index >80). However, no single-phosphor, single-emitting-center-converted white light-emitting diodes can simultaneously satisfy the color temperature and rendition requirements due to the lack of sufficient red spectral component in the phosphors’ emission spectrum. Here, we report a new yellow Ba 0.93Eu 0.07Al 2O 4 phosphor that has a new orthorhombic lattice structure and exhibits a broad yellow photoluminescence band with sufficient red spectral component. Warm-white emissions with correlated color temperature <4000 K and color rendering index >80more » were readily achieved when combining the Ba 0.93Eu 0.07Al 2O 4 phosphor with a blue light-emitting diode (440–470 nm). This study demonstrates that warm-white light-emitting diodes with high color rendition (i.e., color rendering index >80) can be achieved based on single-phosphor, single-emitting-center conversion.« less

Narrow-band tunable terahertz emission from ferrimagnetic Mn{sub 3-x}Ga thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Awari, N.; University of Groningen, 9747 AG Groningen; Kovalev, S., E-mail: s.kovalev@hzdr.de, E-mail: c.fowley@hzdr.de, E-mail: rodek@tcd.ie

2016-07-18

Narrow-band terahertz emission from coherently excited spin precession in metallic ferrimagnetic Mn{sub 3-x}Ga Heusler alloy nanofilms has been observed. The efficiency of the emission, per nanometer film thickness, is comparable or higher than that of classical laser-driven terahertz sources based on optical rectification. The center frequency of the emission from the films can be tuned precisely via the film composition in the range of 0.20–0.35 THz, making this type of metallic film a candidate for efficient on-chip terahertz emitters. Terahertz emission spectroscopy is furthermore shown to be a sensitive probe of magnetic properties of ultra-thin films.

Contributions from gallium vacancies and carbon-related defects to the ``yellow luminescence'' in GaN

NASA Astrophysics Data System (ADS)

Armitage, R.; Hong, William; Yang, Qing; Feick, H.; Gebauer, J.; Weber, E. R.; Hautakangas, S.; Saarinen, K.

2003-05-01

Carbon-doped GaN layers grown by molecular-beam epitaxy are studied with photoluminescence and positron annihilation spectroscopy. Semi-insulating layers doped with >1018 cm-3 carbon show a strong luminescence band centered at ˜2.2 eV (yellow luminescence). The absolute intensity of the 2.2 eV band is compared with the gallium vacancy concentration determined by positron annihilation spectroscopy. The results indicate that a high concentration of gallium vacancies is not necessary for yellow luminescence and that there is in fact a causal relationship between carbon and the 2.2 eV band. Markedly different deep-level ionization energies are found for the high-temperature quenching of the 2.2 eV photoluminescence in carbon-doped and reference samples. We propose that while the model of Neugebauer and Van de Walle [Appl. Phys. Lett. 69, 503 (1996)] applies for GaN of low carbon concentration, a different yellow luminescence mechanism is involved when the interstitial carbon concentration is comparable to or exceeds the gallium vacancy concentration.

Behavioural responses of the yellow emitting annelid Tomopteris helgolandica to photic stimuli.

PubMed

Gouveneaux, Anaïd; Gielen, Marie-Charlotte; Mallefet, Jérôme

2018-05-01

In contrast to most mesopelagic bioluminescent organisms specialised in the emission and reception of blue light, the planktonic annelid Tomopteris helgolandica produces yellow light. This unusual feature has long been suggested to serve for intraspecific communication. Yet, this virtually admitted hypothesis has never been tested. In this behavioural study of spectral colour sensitivity, we first present an illustrated repertoire of the postures and action patterns described by captive specimens. Then video tracking and motion analysis are used to quantify the behavioural responses of singled out worms to photic stimuli imitating intraspecific (yellow) or interspecific (blue) bioluminescent signals. We show the ability of T. helgolandica to react and to contrast its responses to bioluminescent-like blue and yellow light signals. In particular, the attractive effect of yellow light and the variation of angular velocity observed according to the pattern of yellow stimuli (flashes versus glows) support the intraspecific communication hypothesis. However, given the behavioural patterns of T. helgolandica, including mechanically induced light emission, the possibility that bioluminescence may be part of escape/defence responses to predation, should remain an open question. Copyright © 2018 John Wiley & Sons, Ltd.

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

NASA Astrophysics Data System (ADS)

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

2013-09-01

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 μm 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 μm), M15 (10.8 μm) and M16's (12.0 μm) 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.

Io's Sodium Cloud On-Chip Format (Clear and Green-Yellow Filters Superimposed)

NASA Technical Reports Server (NTRS)

1997-01-01

This image of Jupiter's moon Io and its surrounding sky is shown in false color. The solid state imaging (CCD) system on NASA's Galileo spacecraft originally took two images of this scene, one through a clear filter and one through a green-yellow filter. [Versions of these images have been released over the past 3 days.] This picture was created by: (i) adding green color to the image taken through the green-yellow filter, and red color to the image taken through the clear filter; (ii) superimposing the two resulting images. Thus features in this picture which are purely green (or purely red) originally appeared only in the green-yellow (or clear) filter image of this scene. Features which are yellowish appeared in both filters. North is at the top, and east is to the right.

This image reveals several new things about this scene. For example:

(1) The reddish emission south of Io came dominantly through the clear filter. It therefore probably represents scattered light from Io's lit crescent and Prometheus' plume, rather than emission from Io's Sodium Cloud (which came through both filters).

(2) The roundish red spot in Io's southern hemisphere contains a small yellow spot. This means that some thermal emission from the volcano Pele was detected by the green-yellow filter (as well as by the clear filter).

(3) The sky contains several concentrated yellowish spots which were thus seen at the same location on the sky through both filters (one such spot appears in the picture's northeast corner). These spots are almost certainly stars. By contrast, the eastern half of this image contains a number of green spots whose emission was thus detected by the green-yellow filter only. Since any star visible through the green-yellow filter would also be visible through the clear filter, these green spots are probably artifacts (e.g., cosmic ray hits on the CCD sensor).

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space

Topical Review: Development of overgrown semi-polar GaN for high efficiency green/yellow emission

NASA Astrophysics Data System (ADS)

Wang, T.

2016-09-01

The most successful example of large lattice-mismatched epitaxial growth of semiconductors is the growth of III-nitrides on sapphire, leading to the award of the Nobel Prize in 2014 and great success in developing InGaN-based blue emitters. However, the majority of achievements in the field of III-nitride optoelectronics are mainly limited to polar GaN grown on c-plane (0001) sapphire. This polar orientation poses a number of fundamental issues, such as reduced quantum efficiency, efficiency droop, green and yellow gap in wavelength coverage, etc. To date, it is still a great challenge to develop longer wavelength devices such as green and yellow emitters. One clear way forward would be to grow III-nitride device structures along a semi-/non-polar direction, in particular, a semi-polar orientation, which potentially leads to both enhanced indium incorporation into GaN and reduced quantum confined Stark effects. This review presents recent progress on developing semi-polar GaN overgrowth technologies on sapphire or Si substrates, the two kinds of major substrates which are cost-effective and thus industry-compatible, and also demonstrates the latest achievements on electrically injected InGaN emitters with long emission wavelengths up to and including amber on overgrown semi-polar GaN. Finally, this review presents a summary and outlook on further developments for semi-polar GaN based optoelectronics.

Thermally switchable photonic band-edge to random laser emission in dye-doped cholesteric liquid crystals

NASA Astrophysics Data System (ADS)

Ye, Lihua; Wang, Yan; Feng, Yangyang; Liu, Bo; Gu, Bing; Cui, Yiping; Lu, Yanqing

2018-03-01

By changing the doping concentration of the chiral agent to adjust the relative position of the reflection band of cholesteric liquid crystals and the fluorescence emission spectrum of the dye, photonic band-edge and random lasing were observed, respectively. The reflection band of the cholesteric phase liquid crystal can also be controlled by adjusting the temperature: the reflection band is blue-shifted with increasing temperature, and a reversible switch from photonic band-edge to random lasing is obtained. Furthermore, the laser line width can be thermally adjusted from 1.1 nm (at 27 °C) to 4.6 nm (at 32.1 °C). A thermally tunable polarization state of a random laser from dual cells was observed, broadening the field of application liquid crystal random lasers.

ALMA BAND 8 CONTINUUM EMISSION FROM ORION SOURCE I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirota, Tomoya; Matsumoto, Naoko; Machida, Masahiro N.

2016-12-20

We have measured continuum flux densities of a high-mass protostar candidate, a radio source I in the Orion KL region (Orion Source I) using the Atacama Large Millimeter/Submillimeter Array (ALMA) at band 8 with an angular resolution of 0.″1. The continuum emission at 430, 460, and 490 GHz associated with Source I shows an elongated structure along the northwest–southeast direction perpendicular to the so-called low-velocity bipolar outflow. The deconvolved size of the continuum source, 90 au × 20 au, is consistent with those reported previously at other millimeter/submillimeter wavelengths. The flux density can be well fitted to the optically thick blackbody spectral energy distribution, and the brightness temperaturemore » is evaluated to be 700–800 K. It is much lower than that in the case of proton–electron or H{sup −} free–free radiations. Our data are consistent with the latest ALMA results by Plambeck and Wright, in which the continuum emission was proposed to arise from the edge-on circumstellar disk via thermal dust emission, unless the continuum source consists of an unresolved structure with a smaller beam filling factor.« less

Yellowing reaction in encapsulant of photovoltaic modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shigekuni, T.; Kumano, M.

1997-12-31

To clarify the mechanism of the yellowing reaction in encapsulant used for photovoltaic (PV) modules, a low molecular weight substance in EVA (Ethylene vinyl acetate) under accelerated weathering test (Dew cycle test, 1000 hours) with yellow change and virgin EVA were extracted with methanol. Extracts were chemically analyzed by GCIR (Gas Chromatography Infrared-Ray spectroscopic analysis), GC-AED (Gas Chromatography Atomic Emission Detector), and FDMS (Field Desorption Mass Spectroscopy). The conditions of this accelerated test were based on JIS-K9117. The analysis results showed that 2,6-di-t-butyl-4-methyl phenol of antioxidant and 2-hydroxy-4-octoxy-benzophenone of UV absorbent were consumed after the weathering test and that 3,5-di-t-butyl-4-hydroxy-benzaldehydemore » having yellow color was newly produced. A mechanism of the yellowing reaction in encapsulant was presented here that 2,6-di-t-N-O radical from Bis-2,2,6,6-tetramethyl-4-piperidinyl sebacate to produce 3,5 di-t-butyl-4-hydroxy benzaldehyde.« less

Atmospheric dayglow diagnostics involving the O2(b-X) Atmospheric band emission: Global Oxygen and Temperature (GOAT) mapping

NASA Astrophysics Data System (ADS)

Slanger, T. G.; Pejaković, D. A.; Kostko, O.; Matsiev, D.; Kalogerakis, K. S.

2017-03-01

The terrestrial dayglow displays prominent emission features from the 0-0 and 1-1 bands of the O2 Atmospheric band system in the 760-780 nm region. We present an analysis of observations in this wavelength region recorded by the Space Shuttle during the Arizona Airglow Experiment. A major conclusion is that the dominant product of O(1D) + O2 energy transfer is O2(b, v = 1), a result that corroborates our previous laboratory studies. Moreover, critical to the interpretation of dayglow is the possible interference by N2 and N2+ bands in the 760-780 nm region, where the single-most important component is the N2 1PG 3-1 band that overlaps with the O2(b-X) 0-0 band. When present, this background must be accounted for to reveal the O2(b-X) 0-0 and 1-1 bands for altitudes at which the O2 and N2/N2+ emissions coincide. Finally, we exploit the very different collisional behavior of the two lowest O2(b) vibrational levels to outline a remote sensing technique that provides information on Atmospheric composition and temperature from space-based observations of the 0-0 and 1-1 O2 atmospheric bands.

Tunable Yellow-Red Photoluminescence and Persistent Afterglow in Phosphors Ca4LaO(BO3)3:Eu3+ and Ca4EuO(BO3)3.

PubMed

Chen, Zhen; Pan, Yuexiao; Xi, Luqing; Pang, Ran; Huang, Shaoming; Liu, Guokui

2016-11-07

In most Eu 3+ activated phosphors, only red luminescence from the 5 D 0 is obtainable, and efficiency is limited by concentration quenching. Herein we report a new phosphor of Ca 4 LaO(BO 3 ) 3 :Eu 3+ (CLBO:Eu) with advanced photoluminescence properties. The yellow luminescence emitted from the 5 D 1,2 states is not thermally quenched at room temperature. The relative intensities of the yellow and red emission bands depend strongly on the Eu 3+ doping concentration. More importantly, concentration quenching of Eu 3+ photoluminescence is absent in this phosphor, and the stoichiometric compound of Ca 4 EuO(BO 3 ) 3 emits stronger luminescence than the Eu 3+ doped compounds of CLBO:Eu; it is three times stronger than that of a commercial red phosphor of Y 2 O 3 :Eu 3+ . Another beneficial phenomenon is that ligand-to-metal charge transfer (CT) transitions occur in the long UV region with the lowest charge transfer band (CTB) stretched down to about 3.67 eV (∼330 nm). The CT transitions significantly enhance Eu 3+ excitation, and thus result in stronger photoluminescence and promote trapping of excitons for persistent afterglow emission. Along with structure characterization, optical spectra and luminescence dynamics measured under various conditions as a function of Eu 3+ doping, temperature, and excitation wavelength are analyzed for a fundamental understanding of electronic interactions and for potential applications.

Spectral modification of the laser emission of a terahertz quantum cascade laser induced by broad-band double pulse injection seeding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Markmann, Sergej, E-mail: sergej.markmann@ruhr-uni-bochum.de; Nong, Hanond, E-mail: nong.hanond@ruhr-uni-bochum.de; Hekmat, Negar

2015-09-14

We demonstrate by injection seeding that the spectral emission of a terahertz (THz) quantum cascade laser (QCL) can be modified with broad-band THz pulses whose bandwidths are greater than the QCL bandwidth. Two broad-band THz pulses delayed in time imprint a modulation on the single THz pulse spectrum. The resulting spectrum is used to injection seed the THz QCL. By varying the time delay between the THz pulses, the amplitude distribution of the QCL longitudinal modes is modified. By applying this approach, the QCL emission is reversibly switched from multi-mode to single mode emission.

Yellow Fever

MedlinePlus

... Testing Vaccine Information Testing for Vaccine Adverse Events Yellow fever Vaccine Continuing Education Course Yellow Fever Home Prevention Vaccine Vaccine Recommendations Reactions to Yellow Fever Vacine Yellow Fever Vaccine, Pregnancy, & ... Transmission Symptoms, Diagnosis, & Treatment Maps Africa ...

Mixing of phosphorescent and exciplex emission in efficient organic electroluminescent devices.

PubMed

Cherpak, Vladyslav; Stakhira, Pavlo; Minaev, Boris; Baryshnikov, Gleb; Stromylo, Evgeniy; Helzhynskyy, Igor; Chapran, Marian; Volyniuk, Dmytro; Hotra, Zenon; Dabuliene, Asta; Tomkeviciene, Ausra; Voznyak, Lesya; Grazulevicius, Juozas Vidas

2015-01-21

We fabricated a yellow organic light-emitting diode (OLED) based on the star-shaped donor compound tri(9-hexylcarbazol-3-yl)amine, which provides formation of the interface exciplexes with the iridium(III) bis[4,6-difluorophenyl]-pyridinato-N,C2']picolinate (FIrpic). The exciplex emission is characterized by a broad band and provides a condition to realize the highly effective white OLED. It consists of a combination of the blue phosphorescent emission from the FIrpic complex and a broad efficient delayed fluorescence induced by thermal activation with additional direct phosphorescence from the triplet exciplex formed at the interface. The fabricated exciplex-type device exhibits a high brightness of 38 000 cd/m(2) and a high external quantum efficiency.

Identification of yellow luminescence centers in Be-doped GaN through pressure-dependent studies

NASA Astrophysics Data System (ADS)

Teisseyre, Henryk; Lyons, John L.; Kaminska, Agata; Jankowski, Dawid; Jarosz, Dawid; Boćkowski, Michał; Suchocki, Andrzej; Van de Walle, Chris G.

2017-06-01

Effective acceptor doping of wide-band-gap semiconductors is still an outstanding problem. Beryllium has been suggested as a shallow acceptor in GaN, but despite sporadic announcements, Be-induced p-type doping has never been practically realized. Be-doped GaN possesses two luminescence bands; one at 3.38 eV and a second near 2.2 eV at an energy close to that of the parasitic yellow luminescence often found in undoped GaN crystals. We have performed high hydrostatic pressure studies of bulk, Be-doped gallium nitride crystals using the diamond anvil cell technique. We observed a splitting of the yellow luminescence line under hydrostatic pressure into two components, one which is strongly dependent on applied pressure and another whose pressure dependence is more modest. Together with hybrid functional calculations, we attribute the strongly-varying component to the beryllium-oxygen complex. The second component of the yellow luminescence possesses very similar pressure behavior to the yellow luminescence observed in undoped samples grown by the same method, behavior which we find consistent with the CN acceptor. At higher pressure, we observe the vanishing of yellow luminescence and a rapid increase in luminescence intensity of the UV line. We explain this as the pressure-induced transformation of the Be-O complex from a highly localized state with large lattice relaxation to a delocalized state with limited lattice relaxation.

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)

Joblin, C.; Tielens, A. G. G. M.; Allamandola, L. J.; Geballe, T. R.

1996-01-01

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.

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)

Joblin, C.; Tielens, A. G.; Allamandola, L. J.; Geballe, T. R.

1996-01-01

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.

On-orbit Characterization of RVS for MODIS Thermal Emissive Bands

NASA Technical Reports Server (NTRS)

Xiong, X.; Salomonson, V.; Chiang, K.; Wu, A.; Guenther, B.; Barnes, W.

2004-01-01

Response versus scan angle (RVS) is a key calibration parameter for remote sensing radiometers that make observations using a scanning optical system, such as a scan mirror in MODIS and GLI or a rotating telescope in SeaWiFS and VIIRS, since the calibration is typically performed at a fixed viewing angle while the Earth scene observations are made over a range of viewing angles. Terra MODIS has been in operation for more than four years since its launch in December 1999. It has 36 spectral bands covering spectral range from visible (VIS) to long-wave infrared (LWIR). It is a cross-track scanning radiometer using a two-sided paddle wheel scan mirror, making observations over a wide field of view (FOV) of +/-55 deg from the instrument nadir. This paper describes on-orbit characterization of MODIS RVS for its thermal emissive bands (TEB), using the Earth view data collected during Terra spacecraft deep space maneuvers (DSM). Comparisons with pre-launch analysis and early on-orbit measurements are also provided.

Broad emission band of Yb3+ in the nonlinear Nb:RbTiOPO4 crystal: origin and applications.

PubMed

Carvajal, J J; Ciatto, G; Mateos, X; Schmidt, A; Griebner, U; Petrov, V; Boulon, G; Brenier, A; Peña, A; Pujol, M C; Aguiló, M; Díaz, F

2010-03-29

By means of micro-structural and optical characterization of the Yb:Nb:RbTiOPO(4) crystal, we demonstrated that the broad emission band of Yb(3+) in these crystals is due to the large splitting of the ytterbium ground state only, and not to a complex multisite occupation by the ytterbium ions in the crystals. We used this broad emission band to demonstrate wide laser tuning range and generation of femtosecond laser pulses. Passive mode-locked laser operation has been realized by using a semiconductor saturable absorber mirror, generating ultra short laser pulses of 155 fs, which were very stable in time, under Ti:sapphire laser pumping at 1053 nm.

The ALI-ARMS Code for Modeling Atmospheric non-LTE Molecular Band Emissions: Current Status and Applications

NASA Technical Reports Server (NTRS)

Kutepov, A. A.; Feofilov, A. G.; Manuilova, R. O.; Yankovsky, V. A.; Rezac, L.; Pesnell, W. D.; Goldberg, R. A.

2008-01-01

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.

Structural and luminescence properties of self-yellow emitting undoped and (Ca, Ba, Sr)-doped Zn2V2O7 phosphors synthesized by combustion method

NASA Astrophysics Data System (ADS)

Foka, Kewele E.; Dejene, Birhanu F.; Koao, Lehlohonolo F.; Swart, Hendrik C.

2018-04-01

A self-activated yellow emitting Zn2V2O7 was synthesized by combustion method. The influence of the processing parameters such as synthesis temperature and dopants concentration on the structure, morphology and luminescence properties was investigated. The X-ray diffraction (XRD) analysis confirmed that the samples have a tetragonal structure and no significant structural change was observed in varying both the synthesis temperature and the dopants concentration. The estimated average crystallite size was 78 nm for the undoped samples synthesized at different temperatures and 77 nm for the doped samples. Scanning electron microscope (SEM) images showed agglomerated hexagonal-shaped particles with straight edges at low temperatures and the shape of the particles changed to cylindrical structures at moderate temperatures. At higher temperatures, the morphology changed completely. However, the morphologies of the doped samples looked alike. The photoluminescence (PL) of the product exhibited broad emission bands ranging from 400 to 800 nm. The best luminescence intensity was observed for the undoped Zn2V2O7 samples and those synthesized at 600 ℃ . Any further increase in synthesis temperature, type and concentration of dopants led to a decrease in the luminescence intensity. The broad band emission peak of Zn2V2O7 consisted of two broad bands corresponding to emissions from the Em1 (3T2→1A1) and Em2 (3T1→1A1) transitions.

Strong Photonic-Band-Gap Effect on the Spontaneous Emission in 3D Lead Halide Perovskite Photonic Crystals.

PubMed

Zhou, Xue; Li, Mingzhu; Wang, Kang; Li, Huizeng; Li, Yanan; Li, Chang; Yan, Yongli; Zhao, Yongsheng; Song, Yanlin

2018-03-25

Stimulated emission in perovskite-embedded polymer opal structures is investigated. A polymer opal structure is filled with a perovskite, and perovskite photonic crystals are prepared. The spontaneous emission of the perovskite embedded in the polymer opal structures exhibits clear signatures of amplified spontaneous emission (ASE) via gain modulation. The difference in refractive-index contrast between the perovskite and the polymer opal is large enough for retaining photonic-crystals properties. The photonic band gap has a strong effect on the fluorescence emission intensity and lifetime. The stimulated emission spectrum exhibits a narrow ASE rather than a wide fluorescence peak in the thin film. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bias-polarity-dependent UV/visible transferable electroluminescence from ZnO nanorod array LED with graphene oxide electrode supporting layer

NASA Astrophysics Data System (ADS)

Liu, Weizhen; Wang, Wei; Xu, Haiyang; Li, Xinghua; Yang, Liu; Ma, Jiangang; Liu, Yichun

2015-09-01

A simple top electrode preparation process, employing continuous graphene oxide films as electrode supporting layers, was adopted to fabricate a ZnO nanorod array/p-GaN heterojunction LED. The achieved LED demonstrated different electroluminescence behaviors under forward and reverse biases: a yellow-red emission band was observed under forward bias, whereas a blue-UV emission peak was obtained under reverse bias. Electroluminescence spectra under different currents and temperatures, as well as heterojunction energy-band alignments, reveal that the yellow-red emission under forward bias originates from recombinations related to heterointerface defects, whereas the blue-UV electroluminescence under reverse bias is ascribed to transitions from near-band-edge and Mg-acceptor levels in p-GaN.

Generation Process of Large-Amplitude Upper-Band Chorus Emissions Observed by Van Allen Probes

DOE PAGES

Kubota, Yuko; Omura, Yoshiharu; Kletzing, Craig; ...

2018-04-19

In this paper, we analyze large-amplitude upper-band chorus emissions measured near the magnetic equator by the Electric and Magnetic Field Instrument Suite and Integrated Science instrument package on board the Van Allen Probes. In setting up the parameters of source electrons exciting the emissions based on theoretical analyses and observational results measured by the Helium Oxygen Proton Electron instrument, we calculate threshold and optimum amplitudes with the nonlinear wave growth theory. We find that the optimum amplitude is larger than the threshold amplitude obtained in the frequency range of the chorus emissions and that the wave amplitudes grow between themore » threshold and optimum amplitudes. Finally, in the frame of the wave growth process, the nonlinear growth rates are much greater than the linear growth rates.« less

Generation Process of Large-Amplitude Upper-Band Chorus Emissions Observed by Van Allen Probes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kubota, Yuko; Omura, Yoshiharu; Kletzing, Craig

In this paper, we analyze large-amplitude upper-band chorus emissions measured near the magnetic equator by the Electric and Magnetic Field Instrument Suite and Integrated Science instrument package on board the Van Allen Probes. In setting up the parameters of source electrons exciting the emissions based on theoretical analyses and observational results measured by the Helium Oxygen Proton Electron instrument, we calculate threshold and optimum amplitudes with the nonlinear wave growth theory. We find that the optimum amplitude is larger than the threshold amplitude obtained in the frequency range of the chorus emissions and that the wave amplitudes grow between themore » threshold and optimum amplitudes. Finally, in the frame of the wave growth process, the nonlinear growth rates are much greater than the linear growth rates.« less

Target-specific nanoparticles containing a broad band emissive NIR dye for the sensitive detection and characterization of tumor development.

PubMed

Behnke, Thomas; Mathejczyk, Julia E; Brehm, Robert; Würth, Christian; Gomes, Fernanda Ramos; Dullin, Christian; Napp, Joanna; Alves, Frauke; Resch-Genger, Ute

2013-01-01

Current optical probes including engineered nanoparticles (NPs) are constructed from near infrared (NIR)-emissive organic dyes with narrow absorption and emission bands and small Stokes shifts prone to aggregation-induced self-quenching. Here, we present the new asymmetric cyanine Itrybe with broad, almost environment-insensitive absorption and emission bands in the diagnostic window, offering a unique flexibility of the choice of excitation and detection wavelengths compared to common NIR dyes. This strongly emissive dye was spectroscopically studied in different solvents and encapsulated into differently sized (15, 25, 100 nm) amino-modified polystyrene NPs (PSNPs) via a one-step staining procedure. As proof-of-concept for its potential for pre-/clinical imaging applications, Itrybe-loaded NPs were surface-functionalized with polyethylene glycol (PEG) and the tumor-targeting antibody Herceptin and their binding specificity to the tumor-specific biomarker HER2 was systematically assessed. Itrybe-loaded NPs display strong fluorescence signals in vitro and in vivo and Herceptin-conjugated NPs bind specifically to HER2 as demonstrated in immunoassays as well as on tumor cells and sections from mouse tumor xenografts in vitro. This demonstrates that our design strategy exploiting broad band-absorbing and -emitting dyes yields versatile and bright NIR probes with a high potential for e.g. the sensitive detection and characterization of tumor development and progression. Copyright © 2012 Elsevier Ltd. All rights reserved.

Vibrational spectroscopic analyses of unique yellow feather pigments (spheniscins) in penguins.

PubMed

Thomas, Daniel B; McGoverin, Cushla M; McGraw, Kevin J; James, Helen F; Madden, Odile

2013-06-06

Many animals extract, synthesize and refine chemicals for colour display, where a range of compounds and structures can produce a diverse colour palette. Feather colours, for example, span the visible spectrum and mostly result from pigments in five chemical classes (carotenoids, melanins, porphyrins, psittacofulvins and metal oxides). However, the pigment that generates the yellow colour of penguin feathers appears to represent a sixth, poorly characterized class of feather pigments. This pigment class, here termed 'spheniscin', is displayed by half of the living penguin genera; the larger and richer colour displays of the pigment are highly attractive. Using Raman and mid-infrared spectroscopies, we analysed yellow feathers from two penguin species (king penguin, Aptenodytes patagonicus; macaroni penguin, Eudyptes chrysolophus) to further characterize spheniscin pigments. The Raman spectrum of spheniscin is distinct from spectra of other feather pigments and exhibits 17 distinctive spectral bands between 300 and 1700 cm(-1). Spectral bands from the yellow pigment are assigned to aromatically bound carbon atoms, and to skeletal modes in an aromatic, heterocyclic ring. It has been suggested that the penguin pigment is a pterin compound; Raman spectra from yellow penguin feathers are broadly consistent with previously reported pterin spectra, although we have not matched it to any known compound. Raman spectroscopy can provide a rapid and non-destructive method for surveying the distribution of different classes of feather pigments in the avian family tree, and for correlating the chemistry of spheniscin with compounds analysed elsewhere. We suggest that the sixth class of feather pigments may have evolved in a stem-lineage penguin and endowed modern penguins with a costly plumage trait that appears to be chemically unique among birds.

Vibrational spectroscopic analyses of unique yellow feather pigments (spheniscins) in penguins

PubMed Central

Thomas, Daniel B.; McGoverin, Cushla M.; McGraw, Kevin J.; James, Helen F.; Madden, Odile

2013-01-01

Many animals extract, synthesize and refine chemicals for colour display, where a range of compounds and structures can produce a diverse colour palette. Feather colours, for example, span the visible spectrum and mostly result from pigments in five chemical classes (carotenoids, melanins, porphyrins, psittacofulvins and metal oxides). However, the pigment that generates the yellow colour of penguin feathers appears to represent a sixth, poorly characterized class of feather pigments. This pigment class, here termed ‘spheniscin’, is displayed by half of the living penguin genera; the larger and richer colour displays of the pigment are highly attractive. Using Raman and mid-infrared spectroscopies, we analysed yellow feathers from two penguin species (king penguin, Aptenodytes patagonicus; macaroni penguin, Eudyptes chrysolophus) to further characterize spheniscin pigments. The Raman spectrum of spheniscin is distinct from spectra of other feather pigments and exhibits 17 distinctive spectral bands between 300 and 1700 cm−1. Spectral bands from the yellow pigment are assigned to aromatically bound carbon atoms, and to skeletal modes in an aromatic, heterocyclic ring. It has been suggested that the penguin pigment is a pterin compound; Raman spectra from yellow penguin feathers are broadly consistent with previously reported pterin spectra, although we have not matched it to any known compound. Raman spectroscopy can provide a rapid and non-destructive method for surveying the distribution of different classes of feather pigments in the avian family tree, and for correlating the chemistry of spheniscin with compounds analysed elsewhere. We suggest that the sixth class of feather pigments may have evolved in a stem-lineage penguin and endowed modern penguins with a costly plumage trait that appears to be chemically unique among birds. PMID:23516063

Activation of an intense near band edge emission from ZnTe/ZnMgTe core/shell nanowires grown on silicon.

PubMed

Wojnar, P; Szymura, M; Zaleszczyk, W; Kłopotowski, L; Janik, E; Wiater, M; Baczewski, L T; Kret, S; Karczewski, G; Kossut, J; Wojtowicz, T

2013-09-13

The absence of luminescence in the near band edge energy region of Te-anion based semiconductor nanowires grown by gold catalyst assisted molecular beam epitaxy has strongly limited their applications in the field of photonics. In this paper, an enhancement of the near band edge emission intensity from ZnTe/ZnMgTe core/shell nanowires grown on Si substrates is reported. A special role of the use of Si substrates instead of GaAs substrates is emphasized, which results in an increase of the near band edge emission intensity by at least one order of magnitude accompanied by a simultaneous reduction of the defect related luminescence. A possible explanation of this effect relies on the presence of Ga-related deep level defects in structures grown on GaAs substrates, which are absent when Si substrates are used. Monochromatic mapping of the cathodoluminescence clearly confirms that the observed emission originates, indeed, from the ZnTe/ZnMgTe core/shell nanowires, whereas individual objects are studied by means of microphotoluminescence.

High-Performance Blue-Excitable Yellow Phosphor Obtained from an Activated Solvochromic Bismuth-Fluorophore Metal–Organic Framework

DOE PAGES

Deibert, Benjamin J.; Velasco, Ever; Liu, Wei; ...

2016-06-23

Here, we report the synthesis, structure, and photoluminescence properties of a new bismuth based luminescent metal-organic framework (LMOF). The framework is comprised of a 9-coordinated Bi 3+ building unit and 4', 4''', 4''''', 4'''''''-(ethene-1,1,2,2-tetrayl)tetrakis([1,1'-biphenyl]-4-carboxylic acid) (H 4tcbpe) organic linker, which has strong yellow aggregation induced emission (AIE). The structure can be viewed as two interpenetrated 4,4-anionic nets that are stabilized by K + ions forming one-dimensional helical inorganic chains by connecting bismuth nodes through shared oxygen bonds. The as-made LMOF has a bluish emission centered at 459 nm with an internal quantum yield of 57% when excited at 360 nm.more » The emission properties of the LMOF were found to be highly solvochromic with respect to DMF. Upon partial solvent removal, the framework undergoes significant red-shifting to a greenish emission centered at 500 nm. Complete removal of DMF results in additional red-shifting fluorescence coupled with structural changes. The resulting material has strong blue-excitable (455 nm) yellow emission centered at 553 nm, with a quantum yield of 74%, which is maintained after heating in air for 5 days at 90°C. This is the second highest quantum yield value for blue-excited yellow emission among all reported LMOFs.« less

High-Performance Blue-Excitable Yellow Phosphor Obtained from an Activated Solvochromic Bismuth-Fluorophore Metal–Organic Framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deibert, Benjamin J.; Velasco, Ever; Liu, Wei

Here, we report the synthesis, structure, and photoluminescence properties of a new bismuth based luminescent metal-organic framework (LMOF). The framework is comprised of a 9-coordinated Bi 3+ building unit and 4', 4''', 4''''', 4'''''''-(ethene-1,1,2,2-tetrayl)tetrakis([1,1'-biphenyl]-4-carboxylic acid) (H 4tcbpe) organic linker, which has strong yellow aggregation induced emission (AIE). The structure can be viewed as two interpenetrated 4,4-anionic nets that are stabilized by K + ions forming one-dimensional helical inorganic chains by connecting bismuth nodes through shared oxygen bonds. The as-made LMOF has a bluish emission centered at 459 nm with an internal quantum yield of 57% when excited at 360 nm.more » The emission properties of the LMOF were found to be highly solvochromic with respect to DMF. Upon partial solvent removal, the framework undergoes significant red-shifting to a greenish emission centered at 500 nm. Complete removal of DMF results in additional red-shifting fluorescence coupled with structural changes. The resulting material has strong blue-excitable (455 nm) yellow emission centered at 553 nm, with a quantum yield of 74%, which is maintained after heating in air for 5 days at 90°C. This is the second highest quantum yield value for blue-excited yellow emission among all reported LMOFs.« less

[Yellow fever].

PubMed

Sabbatani, Sergio; Fiorino, Sirio

2007-06-01

After the discovery of the New World, yellow fever proved to be an important risk factor of morbidity and mortality for Caribbean populations. In the following centuries epidemic risk, expanded by sea trade and travel, progressively reached the settlements in North America and Brazil as well as the Atlantic seaboard of tropical and equatorial Africa. In the eighteenth century and the first half of the nineteenth century epidemics of yellow fever were reported in some coastal towns in the Iberian peninsula, French coast, Great Britain and Italy, where, in 1804 at Leghorn, only one epidemic was documented. Prevention and control programs against yellow fever, developed at the beginning of the twentieth century in Cuba and in Panama, were a major breakthrough in understanding definitively its aetiology and pathogenesis. Subsequently, further advances in knowledge of yellow fever epidemiology were obtained when French scientists, working in West and Central Africa, showed that monkeys were major hosts of the yellow fever virus (the wild yellow fever virus), besides man. In addition, advances in research, contributing to the development of vaccines against the yellow fever virus in the first half of the nineteenth century, are reported in this paper.

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

PubMed Central

Sreenath, Kesavapillai; Yuan, Zhao; Allen, John R.

2015-01-01

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

Electrical, spectral and optical performance of yellow-green and amber micro-pixelated InGaN light-emitting diodes

NASA Astrophysics Data System (ADS)

Gong, Z.; Liu, N. Y.; Tao, Y. B.; Massoubre, D.; Xie, E. Y.; Hu, X. D.; Chen, Z. Z.; Zhang, G. Y.; Pan, Y. B.; Hao, M. S.; Watson, I. M.; Gu, E.; Dawson, M. D.

2012-01-01

Micro-pixelated InGaN LED arrays operating at 560 and 600 nm, respectively, are demonstrated for what the authors believe to be the first time. Such devices offer applications in areas including bioinstrumentation, visible light communications and optoelectronic tweezers. The devices reported are based on new epitaxial structures, retaining conventional (0 0 0 1) orientation, but incorporating electron reservoir layers which enhance the efficiency of radiative combination in the active regions. A measured output optical power density up to 8 W cm-2 (4.4 W cm-2) has been achieved from a representative pixel of the yellow-green (amber) LED array, substantially higher than that from conventional broad-area reference LEDs fabricated from the same wafer material. Furthermore, these micro-LEDs can sustain a high current density, up to 4.5 kA cm-2, before thermal rollover. A significant blueshift of the emission wavelength with increasing injection current is observed, however. This blueshift saturates at 45 nm (50 nm) for the yellow-green (amber) LED array, and numerical simulations have been used to gain insight into the responsible mechanisms in this microstructured format of device. In the relatively low-current-density regime (<3.5 kA cm-2) the blueshift is attributable to both the screening of the piezoelectric field by the injected carriers and the band-filling effect, whereas in the high-current regime, it is mainly due to band-filling. Further development of the epitaxial wafer material is expected to improve the current-dependent spectral stability.

Calculation of the X-Ray emission K and L 2,3 bands of metallic magnesium and aluminum with allowance for multielectron effects

NASA Astrophysics Data System (ADS)

Ovcharenko, R. E.; Tupitsyn, I. I.; Savinov, E. P.; Voloshina, E. N.; Dedkov, Yu. S.; Shulakov, A. S.

2014-01-01

A procedure is proposed to calculate the shape of the characteristic X-ray emission bands of metals with allowance for multielectron effects. The effects of the dynamic screening of a core vacancy by conduction electrons and the Auger effect in the valence band are taken into account. The dynamic screening of a core vacancy, which is known to be called the MND (Mahan-Nozeieres-De Dominics) effect, is taken into account by an ab initio band calculation of crystals using the PAW (projected augmented waves) method. The Auger effect is taken into account by a semiempirical method using the approximation of a quadratic dependence of the level width in the valence band on the difference between the level energy and the Fermi energy. The proposed calculation procedure is used to describe the X-ray emission K and L 2,3 bands of metallic magnesium and aluminum crystals. The calculated spectra agree well with the experimental bands both near the Fermi level and in the low-energy part of the spectra in all cases.

Effect of water level changes in the middle reaches of the Yellow River in summer on CO2 emissions from wetlands dominated by Phragmites

NASA Astrophysics Data System (ADS)

Lv, Haibo; Zhang, Hong

2018-04-01

The purpose of this study was to investigate the effect of water level changes (WLC) in the middle reaches of the Yellow River in summer on CO2 emissions from wetlands dominated by Phragmites. The rate of CO2 emissions (RCE) from soil was measured in some Phragmites wetlands selected along the Yumenkou-Tongguan section in this river's middle reaches. An artificial recharge experiment was conducted and the data about this section's water levels for the past 15 years was analyzed. This study found that the water level of this river section changed frequently in the last 11 summers. The effect of WLC depended on air temperature. At low temperatures of between 18.0 and 28.0 °C, WLC contributed to a RCE change from 10.19 mmol.m-2.h-1 to 13.43 mmol.m-2.h-1. When the temperature fell within the normal range of 29.0-35.0 °C, the corresponding changes were from 4.07 mmol.m-2.h-1 to 7.35 mmol.m-2.h-1. When the temperature was higher than 35.0 °C, the corresponding changes increased slightly from 6.47 mmol.m-2.h-1 to 12.41 mmol.m-2.h-1. These suggest that WLC had a considerable effect on CO2 emissions at high and low temperatures. As the water level rose, the RCE increased and then decreased in both types of wetlands. At low temperatures, the most favorable water levels for CO2 emissions were -10 cm and 0 cm. At normal temperatures, the RCE from the two types of wetlands decreased with rising water level. At high temperatures, the most favorable water level was -60 cm for Phragmites wetlands. These results demonstrate that frequent WLC can slow CO2 release from Phragmites wetlands along the middle reaches of the Yellow River. Therefore, research on the effect of WLC on CO2 emissions has practical significance.

Estimating net rainfall, evaporation and water storage of a bare soil from sequential L-band emissivities

NASA Technical Reports Server (NTRS)

Stroosnijder, L.; Lascano, R. J.; Newton, R. W.; Vanbavel, C. H. M.

1984-01-01

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.

Ballistic-electron-emission spectroscopy of Al{sub x}Ga{sub 1{minus}x}As/GaAs heterostructures: Conduction-band offsets, transport mechanisms, and band-structure effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

OShea, J.J.; Brazel, E.G.; Rubin, M.E.

1997-07-01

We report an extensive investigation of semiconductor band-structure effects in single-barrier Al{sub x}Ga{sub 1{minus}x}As/GaAs heterostructures using ballistic-electron-emission spectroscopy (BEES). The transport mechanisms in these single-barrier structures were studied systematically as a function of temperature and Al composition over the full compositional range (0{le}x{le}1). The initial ({Gamma}) BEES thresholds for Al{sub x}Ga{sub 1{minus}x}As single barriers with 0{le}x{le}0.42 were extracted using a model which includes the complete transmission probability of the metal-semiconductor interface and the semiconductor heterostructure. Band offsets measured by BEES are in good agreement with previous measurements by other techniques which demonstrates the accuracy of this technique. BEES measurements atmore » 77 K give the same band-offset values as at room temperature. When a reverse bias is applied to the heterostructures, the BEES thresholds shift to lower voltages in good agreement with the expected bias-induced band-bending. In the indirect band-gap regime ({ital x}{gt}0.45), spectra show a weak ballistic-electron-emission microscopy current contribution due to intervalley scattering through Al{sub x}Ga{sub 1{minus}x}As {ital X} valley states. Low-temperature spectra show a marked reduction in this intervalley current component, indicating that intervalley phonon scattering at the GaAs/Al{sub x}Ga{sub 1{minus}x}As interface produces a significant fraction of this{ital X} valley current. A comparison of the BEES thresholds with the expected composition dependence of the Al{sub x}Ga{sub 1{minus}x}As {Gamma}, {ital L}, and {ital X} points yields good agreement over the entire composition range. {copyright} {ital 1997} {ital The American Physical Society}« less

Defect induced structural inhomogeneity, ultraviolet light emission and near-band-edge photoluminescence broadening in degenerate In2O3 nanowires

NASA Astrophysics Data System (ADS)

Mukherjee, Souvik; Sarkar, Ketaki; Wiederrecht, Gary P.; Schaller, Richard D.; Gosztola, David J.; Stroscio, Michael A.; Dutta, Mitra

2018-04-01

We demonstrate here defect induced changes on the morphology and surface properties of indium oxide (In2O3) nanowires and further study their effects on the near-band-edge (NBE) emission, thereby showing the significant influence of surface states on In2O3 nanostructure based device characteristics for potential optoelectronic applications. In2O3 nanowires with cubic crystal structure (c-In2O3) were synthesized via carbothermal reduction technique using a gold-catalyst-assisted vapor-liquid-solid method. Onset of strong optical absorption could be observed at energies greater than 3.5 eV consistent with highly n-type characteristics due to unintentional doping from oxygen vacancy ({V}{{O}}) defects as confirmed using Raman spectroscopy. A combination of high resolution transmission electron microscopy, x-ray photoelectron spectroscopy and valence band analysis on the nanowire morphology and stoichiometry reveals presence of high-density of {V}{{O}} defects on the surface of the nanowires. As a result, chemisorbed oxygen species can be observed leading to upward band bending at the surface which corresponds to a smaller valence band offset of 2.15 eV. Temperature dependent photoluminescence (PL) spectroscopy was used to study the nature of the defect states and the influence of the surface states on the electronic band structure and NBE emission has been discussed. Our data reveals significant broadening of the NBE PL peak consistent with impurity band broadening leading to band-tailing effect from heavy doping.

Defect induced structural inhomogeneity, ultraviolet light emission and near-band-edge photoluminescence broadening in degenerate In 2 O 3 nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mukherjee, Souvik; Sarkar, Ketaki; Wiederrecht, Gary P.

We demonstrate here defect induced changes on the morphology and surface properties of indium oxide (In2O3) nanowires and further study their effects on the near-band-edge (NBE) emission, thereby showing the significant influence of surface states on In2O3 nanostructure based device characteristics for potential optoelectronic applications. In2O3 nanowires with cubic crystal structure (c-In2O3) were synthesized via carbothermal reduction technique using a gold-catalyst-assisted vapor–liquid–solid method. Onset of strong optical absorption could be observed at energies greater than 3.5 eV consistent with highly n-type characteristics due to unintentional doping from oxygen vacancy (VO) defects as confirmed using Raman spectroscopy. A combination of highmore » resolution transmission electron microscopy, x-ray photoelectron spectroscopy and valence band analysis on the nanowire morphology and stoichiometry reveals presence of high-density of VO defects on the surface of the nanowires. As a result, chemisorbed oxygen species can be observed leading to upward band bending at the surface which corresponds to a smaller valence band offset of 2.15 eV. Temperature dependent photoluminescence (PL) spectroscopy was used to study the nature of the defect states and the influence of the surface states on the electronic band structure and NBE emission has been discussed. Our data reveals significant broadening of the NBE PL peak consistent with impurity band broadening leading to band-tailing effect from heavy doping.« less

Defect induced structural inhomogeneity, ultraviolet light emission and near-band-edge photoluminescence broadening in degenerate In2O3 nanowires.

PubMed

Mukherjee, Souvik; Sarkar, Ketaki; Wiederrecht, Gary P; Schaller, Richard D; Gosztola, David J; Stroscio, Michael A; Dutta, Mitra

2018-04-27

We demonstrate here defect induced changes on the morphology and surface properties of indium oxide (In 2 O 3 ) nanowires and further study their effects on the near-band-edge (NBE) emission, thereby showing the significant influence of surface states on In 2 O 3 nanostructure based device characteristics for potential optoelectronic applications. In 2 O 3 nanowires with cubic crystal structure (c-In 2 O 3 ) were synthesized via carbothermal reduction technique using a gold-catalyst-assisted vapor-liquid-solid method. Onset of strong optical absorption could be observed at energies greater than 3.5 eV consistent with highly n-type characteristics due to unintentional doping from oxygen vacancy [Formula: see text] defects as confirmed using Raman spectroscopy. A combination of high resolution transmission electron microscopy, x-ray photoelectron spectroscopy and valence band analysis on the nanowire morphology and stoichiometry reveals presence of high-density of [Formula: see text] defects on the surface of the nanowires. As a result, chemisorbed oxygen species can be observed leading to upward band bending at the surface which corresponds to a smaller valence band offset of 2.15 eV. Temperature dependent photoluminescence (PL) spectroscopy was used to study the nature of the defect states and the influence of the surface states on the electronic band structure and NBE emission has been discussed. Our data reveals significant broadening of the NBE PL peak consistent with impurity band broadening leading to band-tailing effect from heavy doping.

Spontaneous emission near the edge of a photonic band gap

NASA Astrophysics Data System (ADS)

John, Sajeev; Quang, Tran

1994-08-01

The spectral and dynamical features of spontaneous emission from two and three-level atoms in which one transition frequency lay near the edge of a photonic band gap (PBG) were derived. These features included temporal oscillations, fractionalized steady-state atomic population on the excited state, spectral splitting and subnatural bandwidth. The effect of N-1 unexcited atoms were also taken into account. The direct consequences of photon localization as embodied in the photon-atom bound state were observed. One feasible experimental accomplishment of these effects may ensue from laser-cooled atoms in the void regions of a PBG medium. Another option is the application of an organic impurity molecule such as pentacene. Such molecules were known to show extremely narrow linewidths when placed in fitting solid hosts.

A novel greenish yellow-orange red Ba3Y4O9:Bi(3+),Eu(3+) phosphor with efficient energy transfer for UV-LEDs.

PubMed

Li, Kai; Lian, Hongzhou; Shang, Mengmeng; Lin, Jun

2015-12-21

A series of novel color-tunable Ba3Y4O9:Bi(3+),Eu(3+) phosphors were prepared for the first time via the high-temperature solid-state reaction route. The effect of Bi(3+) concentration on the emission intensity of Ba3Y4O9:Bi(3+) was investigated. The emission spectra of the Ba3Y4O9:Bi(3+),Eu(3+) phosphors present both a greenish yellow band of Bi(3+) emission centered at 523 nm, and many characteristic emission lines of Eu(3+), derived from the allowed (3)P1-(1)S0 transition of the Bi(3+) ion and the (5)D0-(7)FJ transition of the Eu(3+) ion, respectively. The energy transfer phenomenon from Bi(3+) to Eu(3+) ions is observed under UV excitation in Bi(3+), Eu(3+) co-doped Ba3Y4O9 phosphors, and their transfer mechanism is demonstrated to be a resonant type via dipole-quadrupole interaction. The critical distance between Bi(3+) and Eu(3+) for the energy transfer effect was calculated via the concentration quenching and spectral overlap methods. Results show that color tuning from greenish yellow to orange red can be realized by adjusting the mole ratio of Bi(3+) and Eu(3+) concentrations based on the principle of energy transfer. Moreover, temperature-dependent PL properties, CIE chromaticity coordinates and quantum yields of Ba3Y4O9:Bi(3+),Eu(3+) phosphors were also supplied. It is illustrated that the as-prepared Ba3Y4O9:Bi(3+),Eu(3+) phosphors can be potential candidates for color-tunable phosphors applied in UV-pumped LEDs.

Enhancement of white light emission from novel Ca3Y2Si3O12:Dy3+ phosphors with Ce3+ ion codoping

NASA Astrophysics Data System (ADS)

Bandi, Vengala Rao; Nien, Yung-Tang; Chen, In-Gann

2010-07-01

The luminescent properties of the Ce3+ or Dy3+ singly doped and Ce3+/Dy3+ codoped in Ca3Y2Si3O12 novel phosphors were investigated, which are prepared by a sol-gel method. Ce3+ doped phosphor showed a brighter and broader violet-blue color emission band with a maximum peak centered at 389 nm, which is attributed to the parity and spin allowed 5d-4f transition. Photoluminescence spectra reveals that the white color emission is originated from the mixtures of two characteristic emission bands of Dy3+ ion, viz., the 473 nm blue emission (F49/2-H615/2) and the 580 nm yellow emission (F49/2-H613/2). codoping of Ce3+ has enhanced the luminescence of Dy3+ quite significantly upon the UV excitation wavelength (242 nm) and the optimized codopant concentration of Ce3+ is found to be 3 mol %. The mechanism involved in the energy transfer between Ce3+ and Dy3+ has been elucidated by an energy level diagram. The structure and morphology of the prepared samples have been analyzed by x-ray diffraction and transmission electron microscope.

Are TiC Grains a Carrier of the 21 Micron Emission Band Observed around Post-Asymptotic Giant Branch Objects?

NASA Astrophysics Data System (ADS)

Chigai, Takeshi; Yamamoto, Tetsuo; Kaito, Chihiro; Kimura, Yuki

2003-04-01

The carrier of the 21 μm band observed in post-asymptotic giant branch (post-AGB) stars is examined. We analyze the infrared spectra of the TiC clusters measured by von Helden et al. in 2000 and determine the absorption efficiency Q in the 21 μm band. Using Q, we estimate the Ti/Si abundance ratios needed to realize the flux ratios of the 21 and 11 μm emission observed in the infrared spectra of the post-AGB stars exhibiting both 21 and 11 μm emission. In view of the nature of the TiC condensation by which TiC grains are quickly mantled by graphite, we calculate the emission spectra of the graphite-coated TiC grains and other possible types of core-mantle grains and compare with the observed spectra. Both the abundance and condensation considerations strongly suggest that TiC is an implausible carrier of the observed infrared 21 μm feature around carbon-rich post-AGB stars.

Final Report Yellow Bluff Air Study SESD Project ID #11-0068

EPA Pesticide Factsheets

On November 16 – December 16, 2010, and January 23 - 28, 2011, EPA conducted an air sampling study in Yellow Bluff, Alabama in response to concerns about potential health impacts related to air emissions emanating from a nearby paper mill.

Microfluidic White Organic Light-Emitting Diode Based on Integrated Patterns of Greenish-Blue and Yellow Solvent-Free Liquid Emitters

NASA Astrophysics Data System (ADS)

Kobayashi, Naofumi; Kasahara, Takashi; Edura, Tomohiko; Oshima, Juro; Ishimatsu, Ryoichi; Tsuwaki, Miho; Imato, Toshihiko; Shoji, Shuichi; Mizuno, Jun

2015-10-01

We demonstrated a novel microfluidic white organic light-emitting diode (microfluidic WOLED) based on integrated sub-100-μm-wide microchannels. Single-μm-thick SU-8-based microchannels, which were sandwiched between indium tin oxide (ITO) anode and cathode pairs, were fabricated by photolithography and heterogeneous bonding technologies. 1-Pyrenebutyric acid 2-ethylhexyl ester (PLQ) was used as a solvent-free greenish-blue liquid emitter, while 2,8-di-tert-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyltetracene (TBRb)-doped PLQ was applied as a yellow liquid emitter. In order to form the liquid white light-emitting layer, the greenish-blue and yellow liquid emitters were alternately injected into the integrated microchannels. The fabricated electro-microfluidic device successfully exhibited white electroluminescence (EL) emission via simultaneous greenish-blue and yellow emissions under an applied voltage of 100 V. A white emission with Commission Internationale de l’Declairage (CIE) color coordinates of (0.40, 0.42) was also obtained; the emission corresponds to warm-white light. The proposed device has potential applications in subpixels of liquid-based microdisplays and for lighting.

Retrieval of Lower Thermospheric Temperatures from O2 A Band Emission: The MIGHTI Experiment on ICON

NASA Astrophysics Data System (ADS)

Stevens, Michael H.; Englert, Christoph R.; Harlander, John M.; England, Scott L.; Marr, Kenneth D.; Brown, Charles M.; Immel, Thomas J.

2018-02-01

The Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) is a satellite experiment scheduled to launch on NASA's Ionospheric Connection Explorer (ICON) in 2018. MIGHTI is designed to measure horizontal neutral winds and neutral temperatures in the terrestrial thermosphere. Temperatures will be inferred by imaging the molecular oxygen Atmospheric band (A band) on the limb in the lower thermosphere. MIGHTI will measure the spectral shape of the A band using discrete wavelength channels to infer the ambient temperature from the rotational envelope of the band. Here we present simulated temperature retrievals based on the as-built characteristics of the instrument and the expected emission rate profile of the A band for typical daytime and nighttime conditions. We find that for a spherically symmetric atmosphere, the measurement precision is 1 K between 90-105 km during the daytime whereas during the nighttime it increases from 1 K at 90 km to 3 K at 105 km. We also find that the accuracy is 2 K to 11 K for the same altitudes. The expected MIGHTI temperature precision is within the measurement requirements for the ICON mission.

Yellow fever.

PubMed

Monath, Thomas P; Vasconcelos, Pedro F C

2015-03-01

Yellow fever, a mosquito-borne flavivirus disease occurs in tropical areas of South America and Africa. It is a disease of major historical importance, but remains a threat to travelers to and residents of endemic areas despite the availability of an effective vaccine for nearly 70 years. An important aspect is the receptivity of many non-endemic areas to introduction and spread of yellow fever. This paper reviews the clinical aspects, pathogenesis, and epidemiology of yellow fever, with an emphasis on recent changes in the distribution and incidence of the disease. Recent knowledge about yellow fever 17D vaccine mechanism of action and safety are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Yellow fluorescent protein phiYFPv (Phialidium): structure and structure-based mutagenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pletneva, Nadya V.; Pletnev, Vladimir Z., E-mail: vzpletnev@gmail.com; Souslova, Ekaterina

The yellow fluorescent protein phiYFPv with improved folding has been developed from the spectrally identical wild-type phiYFP found in the marine jellyfish Phialidium. The yellow fluorescent protein phiYFPv (λ{sub em}{sup max} ≃ 537 nm) with improved folding has been developed from the spectrally identical wild-type phiYFP found in the marine jellyfish Phialidium. The latter fluorescent protein is one of only two known cases of naturally occurring proteins that exhibit emission spectra in the yellow–orange range (535–555 nm). Here, the crystal structure of phiYFPv has been determined at 2.05 Å resolution. The ‘yellow’ chromophore formed from the sequence triad Thr65-Tyr66-Gly67 adoptsmore » the bicyclic structure typical of fluorophores emitting in the green spectral range. It was demonstrated that perfect antiparallel π-stacking of chromophore Tyr66 and the proximal Tyr203, as well as Val205, facing the chromophore phenolic ring are chiefly responsible for the observed yellow emission of phiYFPv at 537 nm. Structure-based site-directed mutagenesis has been used to identify the key functional residues in the chromophore environment. The obtained results have been utilized to improve the properties of phiYFPv and its homologous monomeric biomarker tagYFP.« less

Research on effect of emission uniformity on X-band relativistic backward oscillator using conformal PIC code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Zaigao

2016-07-15

Explosive emission cathodes (EECs) are adopted in relativistic backward wave oscillators (RBWOs) to generate intense relativistic electron beam. The emission uniformity of the EEC can render saturation of the power generation unstable and the output mode impure. However, the direct measurement of the plasma parameters on the cathode surface is quite difficult and there are very few related numerical study reports about this issue. In this paper, a self-developed three-dimensional conformal fully electromagnetic particle in cell code is used to study the effect of emission uniformity on the X-band RBWO; the electron explosive emission model and the field emission modelmore » are both implemented in the same cathode surface, and the local field enhancement factor is also considered in the field emission model. The RBWO with a random nonuniform EEC is thoroughly studied using this code; the simulation results reveal that when the area ratio of cathode surface for electron explosive emission is 80%, the output power is unstable and the output mode is impure. When the annular EEC does not emit electron in the angle range of 30°, the RBWO can also operate normally.« less

Application of band-target entropy minimization to infrared emission spectroscopy and the reconstruction of pure component emissivities from thin films and liquid samples.

PubMed

Cheng, Shuying; Rajarathnam, D; Meiling, Tan; Garland, Marc

2006-05-01

Thermal emission spectral data sets were collected for a thin solid film (parafilm) and a thin liquid film (isopropanol) on the interval of 298-348 K. The measurements were performed using a conventional Fourier transform infrared (FT-IR) spectrometer with external optical bench and in-house-designed emission cell. Both DTGS and MCT detectors were used. The data sets were analyzed with band-target entropy minimization (BTEM), which is a pure component spectral reconstruction program. Pure component emissivities of the parafilm, isopropanol, and thermal background were all recovered without any a priori information. Furthermore, the emissivities were obtained with increased signal-to-noise ratios, and the signals due to absorbance of thermal radiation by gas-phase moisture and CO2 were significantly reduced. As expected, the MCT results displayed better signal-to-noise ratios than the DTGS results, but the latter results were still rather impressive given the low temperatures used in this study. Comparison is made with spectral reconstruction using the orthogonal projection approach-alternating least squares (OPA-ALS) technique. This contribution introduces the primary equation for emission spectral reconstruction using BTEM and discusses some of the unusual characteristics of thermal emission and their impact on the analysis.

First detection of Mars atmospheric hydroxyl: CRISM Near-IR measurement versus LMD GCM simulation of OH Meinel band emission in the Mars polar winter atmosphere

NASA Astrophysics Data System (ADS)

Todd Clancy, R.; Sandor, Brad J.; García-Muñoz, Antonio; Lefèvre, Franck; Smith, Michael D.; Wolff, Michael J.; Montmessin, Franck; Murchie, Scott L.; Nair, Hari

2013-09-01

Visible and near-IR Meinel band emissions originate from excited OH in the terrestrial upper atmosphere (Meinel, I.A.B. [1950]. Astrophys. J. 111, 555. http://dx.doi.org/10.1086/145296), and have recently been detected in the Venus nightside upper mesosphere (Piccioni, G. et al. [2008]. Astron. Astrophys. 483, L29-L33. http://dx.doi.org/10.1051/0004-6361:200809761). Meinel band observations support key studies of transport and photochemistry in both of these atmospheres. In the case of Mars, OH regulates the basic stability of the CO2 atmosphere to photolytic decomposition (to CO and O2, e.g. Parkinson, T.D., Hunten, D.M. [1972]. J. Atmos. Sci. 29, 1380-1390. http://dx.doi.org/10.1175/1520-0469(1972)029<1380:SAAOOO>2.0.CO;2), and yet has never been measured. We present the first detection of Mars atmospheric OH, associated with CRISM near-IR spectral limb observations of polar night Meinel band emissions centered at 1.45 and 2.9 μm. Meinel band (1-0), (2-1), and (2-0) average limb intensities of 990 ± 280, 1060 ± 480, and 200 ± 100 kiloRayleighs (kR), respectively, are determined for 70-90 NS polar winter latitudes over altitudes of 40-56 km. Additional OH bands, such as (3-2), (3-1), and (4-2), present ⩽1σ measurements. Uncertainty in the (4-2) band emission rate contributes to increased uncertainty in the determination of the O2(1Δg) (0-0)/(0-1) band emission ratio A00/A01=47-12+26. An average profile retrieval for Mars OH polar nightglow indicates 45-55 km altitude levels for volume emission rates (VER) of 0.4 (2-0) to 2 (1-0, 2-1) × 104 photons/(cm3 s). Similar to polar night O2(1Δg) emission (e.g. Clancy, R.T. et al. [2012]. J. Geophys. Res. (Planets) 117, E00J10. http://dx.doi.org/10.1029/2011JE004018), Meinel OH band emission is supported by upper level, winter poleward transport of O and H in the deep Hadley solsticial circulations of Mars. The retrieved OH emission rates are compared to polar winter OH nightglow simulated by the LMD (Laboratoire

EMI survey for maritime satellite, L-band, shipboard terminal

NASA Technical Reports Server (NTRS)

Taylor, R. E.; Brandel, D. L.; Hill, J. S.

1975-01-01

The paper presents results of an onboard EMI survey of an L-band shipboard terminal for operation with two geostationary maritime satellites. Significant EMC results include: (1) antenna noise temperature measurements indicate a maximum of 70 K steady background component at 1.6 GHz at sea for elevation angles of 5 degrees and higher; (2) field intensity measurements from 1-10 GHz show that a L-band terminal can operate simultaneously with onboard S-band and X-band navigation radar; (3) radar transmitter case emissions, below deck, in-band from 1535-1660 MHz, at 1 m distance from the cabinet, are equivalent, or greater than above-deck emissions in the same frequency range; and (4) conducted-emission tests of a ship's power lines to both radars show both narrow band and broad band emissions are 15 dB to 50 dB higher than equivalent U.S. commercial power lines from 150 kHz to 32 MHz.

Impact of Conifer Forest Litter on Microwave Emission at L-Band

NASA Technical Reports Server (NTRS)

Kurum, Mehmet; O'Neill, Peggy E.; Lang, Roger H.; Cosh, Michael H.; Joseph, Alicia T.; Jackson, Thomas J.

2011-01-01

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.

Oxygen Sensing Based on the Yellowing of Newspaper.

PubMed

Yu, Jingjing; Qin, Xingcai; Xian, Xiaojun; Tao, Nongjian

2018-01-26

Newspaper is known to turn yellow over time. We show here that this yellowing process is sensitive to oxygen when exposed to UV light, leading to oxygen sensing. Oxygen sensing is critical to many applications, including industrial process control and breath analysis, but the existing oxygen sensors have limitations, especially for breath analysis that operates at 100% humidity. The UV irradiation also triggers fluorescence emission from newspaper, and the fluorescence intensity depends on oxygen concentration, providing an additional oxygen sensing method. Newspaper is stable in ambient air, and reactive to oxygen only with UV activation, which overcomes the instability issue of a typical colorimetric sensor in ambient air. The newspaper oxygen sensor works in 100% relative humidity air, containing various interferents. These unique properties of newspaper promise low cost and reliable oxygen sensing applications.

2,5-difluorenyl-substituted siloles for the fabrication of high-performance yellow organic light-emitting diodes.

PubMed

Chen, Bin; Jiang, Yibin; Chen, Long; Nie, Han; He, Bairong; Lu, Ping; Sung, Herman H Y; Williams, Ian D; Kwok, Hoi Sing; Qin, Anjun; Zhao, Zujin; Tang, Ben Zhong

2014-02-10

2,3,4,5-Tetraarylsiloles are a class of important luminogenic materials with efficient solid-state emission and excellent electron-transport capacity. However, those exhibiting outstanding electroluminescence properties are still rare. In this work, bulky 9,9-dimethylfluorenyl, 9,9-diphenylfluorenyl, and 9,9'-spirobifluorenyl substituents were introduced into the 2,5-positions of silole rings. The resulting 2,5-difluorenyl-substituted siloles are thermally stable and have low-lying LUMO energy levels. Crystallographic analysis revealed that intramolecular π-π interactions are prone to form between 9,9'-spirobifluorene units and phenyl rings at the 3,4-positions of the silole ring. In the solution state, these new siloles show weak blue and green emission bands, arising from the fluorenyl groups and silole rings with a certain extension of π conjugation, respectively. With increasing substituent volume, intramolecular rotation is decreased, and thus the emissions of the present siloles gradually improved and they showed higher fluorescence quantum yields (Φ(F) =2.5-5.4%) than 2,3,4,5-tetraphenylsiloles. They are highly emissive in solid films, with dominant green to yellow emissions and good solid-state Φ(F) values (75-88%). Efficient organic light-emitting diodes were fabricated by adopting them as host emitters and gave high luminance, current efficiency, and power efficiency of up to 44,100 cd m(-2), 18.3 cd A(-1), and 15.7 lm W(-1), respectively. Notably, a maximum external quantum efficiency of 5.5% was achieved in an optimized device. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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)

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

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.

Identification of Drosophila melanogaster yellow-f and yellow-f2 proteins as dopachrome-conversion enzymes.

PubMed Central

Han, Qian; Fang, Jianmin; Ding, Haizhen; Johnson, Jody K; Christensen, Bruce M; Li, Jianyong

2002-01-01

This study describes the identification of Drosophila yellow-f and yellow-f2 as dopachrome-conversion enzymes responsible for catalysing the conversion of dopachrome into 5,6-dihydroxyindole in the melanization pathway. Drosophila yellow -y gene and yellow -b, -c, -f and -f2 genes were expressed in an insect cell/baculovirus expression system and their corresponding recombinant proteins were screened for dopachrome-conversion enzyme activity. Among the yellow and yellow -related genes, the yellow -f and yellow -f2 genes were identified as the genes coding for Drosophila dopachrome-conversion enzyme based on the high activity of their recombinant proteins in catalysing the production of 5,6-dihydroxyindole from dopachrome. Both yellow-f and yellow-f2 are capable of mediating a decarboxylative structural rearrangement of dopachrome, as well as an isomerization/tautomerization of dopamine chrome and dopa methyl ester chrome. Northern hybridization revealed the transcription of yellow -f in larvae and pupae, but a high abundance of mRNA was observed in later larval and early pupal stages. In contrast, yellow-f2 transcripts were present at all stages, but high abundance of its mRNA was observed in later-stage pupae and adults. These data indicate that yellow-f and yellow-f2 complement each other during Drosophila development and that the yellow-f is involved in larval and pupal melanization, and yellow-f2 plays a major role in melanization reactions in Drosophila during later pupal and adult development. Results from this study provide the groundwork towards a better understanding of the physiological roles of the Drosophila yellow gene family. PMID:12164780

Multivariate regression model for predicting yields of grade lumber from yellow birch sawlogs

Treesearch

Andrew F. Howard; Daniel A. Yaussy

1986-01-01

A multivariate regression model was developed to predict green board-foot yields for the common grades of factory lumber processed from yellow birch factory-grade logs. The model incorporates the standard log measurements of scaling diameter, length, proportion of scalable defects, and the assigned USDA Forest Service log grade. Differences in yields between band and...

Quantification of fluorine traces in solid samples using CaF molecular emission bands in atmospheric air Laser-Induced Breakdown Spectroscopy

NASA Astrophysics Data System (ADS)

Alvarez-Llamas, C.; Pisonero, J.; Bordel, N.

2016-09-01

Direct solid determination of trace amounts of fluorine using Laser-Induced Breakdown Spectroscopy (LIBS) is a challenging task due to the low excitation efficiency of this element. Several strategies have been developed to improve the detection capabilities, including the use of LIBS in a He atmosphere to enhance the signal to background ratios of F atomic emission lines. An alternative method is based on the detection of the molecular compounds that are formed with fluorine in the LIBS plasma. In this work, the detection of CaF molecular emission bands is investigated to improve the analytical capabilities of atmospheric air LIBS for the determination of fluorine traces in solid samples. In particular, Cu matrix samples containing different fluorine concentration (between 50 and 600 μg/g), and variable amounts of Ca, are used to demonstrate the linear relationships between CaF emission signal and F concentration. Limits of detection for fluorine are improved by more than 1 order of magnitude using CaF emission bands versus F atomic lines, in atmospheric-air LIBS. Furthermore, a toothpaste powder sample is used to validate this analytical method. Good agreement is observed between the nominal and the predicted fluorine mass-content.

Terra and Aqua MODIS Thermal Emissive Bands On-Orbit Calibration and Performance

NASA Technical Reports Server (NTRS)

Xiong, Xiaoxiong; Wu, Aisheng; Wenny, Brian N.; Madhavan, Sriharsha; Wang, Zhipeng; Li, Yonghong; Chen, Na; Barnes, William L.; Salomonson, Vincent V.

2015-01-01

Since launch, the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the Terra and Aqua spacecraft have operated successfully for more than 14 and 12 years, respectively. A key instrument for National Aeronautics and Space Administration Earth Observing System missions, MODIS was designed to make continuous observations for studies of Earth's land, ocean, and atmospheric properties and to extend existing data records from heritage Earth observing sensors. The 16 thermal emissive bands (TEBs) (3.75-14.24 micrometers) are calibrated on orbit using a temperature controlled blackbody (BB). Both Terra and Aqua MODIS BBs have displayed minimal drift over the mission lifetime, and the seasonal variations of the BB temperature are extremely small in Aqua MODIS. The long-term gain and noise equivalent difference in temperature performance of the 160 TEB detectors on both MODIS instruments have been well behaved and generally very stable. Small but noticeable variations of Aqua MODIS bands 33-36 (13.34-14.24 micrometer) response in recent years are primarily due to loss of temperature control margin of its passive cryoradiative cooler. As a result, fixed calibration coefficients, previously used by bands when the BB temperature is above their saturation temperatures, are replaced by the focal-plane-temperature-dependent calibration coefficients. This paper presents an overview of the MODIS TEB calibration, the on-orbit performance, and the challenging issues likely to impact the instruments as they continue operating well past their designed lifetime of six years.

Active-passive synergy for interpreting ocean L-band emissivity: Results from the CAROLS airborne campaigns

NASA Astrophysics Data System (ADS)

Martin, A. C. H.; Boutin, J.; Hauser, D.; Dinnat, E. P.

2014-08-01

The impact of the ocean surface roughness on the ocean L-band emissivity is investigated using simultaneous airborne measurements from an L-band radiometer (CAROLS) and from a C-band scatterometer (STORM) acquired in the Gulf of Biscay (off-the French Atlantic coasts) in November 2010. Two synergetic approaches are used to investigate the impact of surface roughness on the L-band brightness temperature (Tb). First, wind derived from the scatterometer measurements is used to analyze the roughness contribution to Tb as a function of wind and compare it with the one simulated by SMOS and Aquarius roughness models. Then residuals from this mean relationship are analyzed in terms of mean square slope derived from the STORM instrument. We show improvement of new radiometric roughness models derived from SMOS and Aquarius satellite measurements in comparison with prelaunch models. Influence of wind azimuth on Tb could not be evidenced from our data set. However, we point out the importance of taking into account large roughness scales (>20 cm) in addition to small roughness scale (5 cm) rapidly affected by wind to interpret radiometric measurements far from nadir. This was made possible thanks to simultaneous estimates of large and small roughness scales using STORM at small (7-16°) and large (30°) incidence angles.

[Research on the emission spectrum of NO molecule's γ-band system by corona discharge].

PubMed

Zhai, Xiao-dong; Ding, Yan-jun; Peng, Zhi-min; Luo, Rui

2012-05-01

The optical emission spectrum of the gamma-band system of NO molecule, A2 sigma+ --> X2 pi(r), has been analyzed and calculated based on the energy structure of NO molecule' doublet states. By employing the theory of diatomic molecular Spectra, some key parameters of equations for the radiative transition intensity were evaluated theoretically, including the potentials of the doublet states of NO molecule's upper and lower energy levels, the electronic transition moments calculated by using r-centroid approximation method, and the Einstein coefficient of different vibrational and rotational levels. The simulated spectrum of the gamma-band system was calculated as a function of different vibrational and rotational temperature. Compared to the theoretical spectroscopy, the measured results were achieved from corona discharge experiments of NO and N2. The vibrational and rotational temperatures were determined approximately by fitting the measured spectral intensities with the calculated ones.

Enhancing the quantum efficiency of InGaN yellow-green light-emitting diodes by growth interruption

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Chunhua; Ma, Ziguang; Zhou, Junming

2014-08-18

We studied the effect of multiple interruptions during the quantum well growth on emission-efficiency enhancement of InGaN-based yellow-green light emitting diodes on c-plane sapphire substrate. The output power and dominant wavelength at 20 mA are 0.24 mW and 556.3 nm. High resolution x-ray diffraction, photoluminescence, and electroluminescence measurements demonstrate that efficiency enhancement could be partially attributed to crystal quality improvement of the active region resulted from reduced In clusters and relevant defects on the surface of InGaN layer by introducing interruptions. The less tilted energy band in the quantum well is also caused by the decrease of In-content gradient along c-axis resultedmore » from In segregation during the interruptions, which increases spatial overlap of electron-hole wavefunction and thus the internal quantum efficiency. The latter also leads to smaller blueshift of dominant wavelength with current increasing.« less

Band-limited Green's Functions for Quantitative Evaluation of Acoustic Emission Using the Finite Element Method

NASA Technical Reports Server (NTRS)

Leser, William P.; Yuan, Fuh-Gwo; Leser, William P.

2013-01-01

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.

CH^+ Spectrum and Diffuse Interstellar Bands Toward Herschel 36 Excited by Dust Emission

NASA Astrophysics Data System (ADS)

Dahlstrom, Julie; Oka, Takeshi; Johnson, Sean; Welty, Daniel E.; Hobbs, Lew M.; York, Donald G.

2012-06-01

All electronic CH^+ interstellar absorption lines so far observed had been limited to the R(0) transition starting from the J = 0 ground level; this is because of the very rapid J = 1 → 0 spontaneous emission with the life time of ˜ 140 s. We have observed the R(1) and Q(1) lines of the A^1π ← X^1Σ band from the excited J = 1 level 40.08 K (27.86 cm-1) above the J = 0 level toward Herschel 36 indicating high radiative temperature of T_r = 17.5 K. The high temperature is most likely due to far infrared dust emission from the Her 36 SE. We have also observed the R_1(3/2) line of CH starting from the excited fine structure level J = 3/2 which is 25.76 - 25.57 K above the J = 1/2 level. The effect of high radiative temperature is also noticed as unique lineshapes of diffuse interstellar bands (DIBs) observed toward Her 36. We have examined seven DIBs including λ 5780.5, λ 5797.1, λ 6190.0, and λ 6613.0 that are correlated with each other with correlation coefficients > 0.93. While for ordinary sightlines the lineshapes of these DIBs are more or less symmetric, those toward Her 36 show a long tail toward the red. This is due to far infrared pumping of high J rotational levels of polar carriers of the DIBs by the dust emission. We have developed a model calculation of relaxation taking into account of both radiative and collisional processes. A linear molecule with about 6 carbon atoms can explain some of the DIBs. For the DIBs we have examined, probably the carriers are of this size since we cannot explain the large difference between the DIBs toward ordinary sightlines and toward Her 36 with larger molecules. Goto, M., Stecklum, B., Linz, H., Feldt, M., Henning, Th., Pascucci, I., and Usuda, T. 2006, ApJ, {649} 299.

The application of high efficient yellow phosphorescent material to white OLEDs

NASA Astrophysics Data System (ADS)

Lin, Jin-Sheng; Ku, Chun-Neng; Huang, Pang-Chi; Wu, Cheng-An; Chang, Meng-Hao; Liou, Jia-Lun; Tseng, Mei-Rurng

2014-10-01

A new type of thiopyridinyl-based iridium molecule (POT) was used as the yellow phosphorescent material in our research. On fabricating a yellow PHOLED by doping POT-02 with host as the emitter, the device achieved a high power efficiency of 66.0 lm/W and an external quantum efficiency of 23.2%. On the other hand, a white organic lightemitting diode (WOLED) with a high power efficiency has been demonstrated by dispersing a host-free, yellow phosphorescent material in-between double blue phosphorescent emitters. In this study, we introduce a simple process for generating yellow emission of a WOLED by using the B/Y/B EML configuration. The B/Y/B EML configuration can achieve a higher efficiency and a smaller color shift with various operational brightness values. Based on the concept of this device, the molecular engineering of the blue phosphorescent host material as well as the light-extraction film, a WOLED with a power efficiency of 103 lm/W and an external quantum efficiency of 38.2% at a practical brightness of 1000 cd/m2 with CIE coordinates (CIEx, y) of (0.36, 0.48) can be achieved.

Calculated hydroxyl A2 sigma --> X2 pi (0, 0) band emission rate factors applicable to atmospheric spectroscopy

NASA Technical Reports Server (NTRS)

Cageao, R. P.; Ha, Y. L.; Jiang, Y.; Morgan, M. F.; Yung, Y. L.; Sander, S. P.

1997-01-01

A calculation of the A2 sigma --> X2 pi (0, 0) band emission rate factors and line center absorption cross sections of OH applicable to its measurement using solar resonant fluorescence in the terrestrial atmosphere is presented in this paper. The most accurate available line parameters have been used. Special consideration has been given to the solar input flux because of its highly structured Fraunhofer spectrum. The calculation for the OH atmospheric emission rate factor in the solar resonant fluorescent case is described in detail with examples and intermediate results. Results of this calculation of OH emission rate factors for individual rotational lines are on average 30% lower than the values obtained in an earlier work.

Comparison of band model calculations of upper atmospheric cooling rates for the 15-micrometer carbon dioxide band

NASA Technical Reports Server (NTRS)

Boughner, R. E.

1985-01-01

Within the atmosphere of the earth, absorption and emission of thermal radiation by the 15-micron CO2 bands are the largest contributors to infrared cooling rates in the stratosphere. Various techniques for calculating cooling rates due to these bands have been described. These techniques can be classified into one of two categories, including 'exact' or line-by-line calculations and other methods. The latter methods are based on broad band emissivity and band absorptance formulations. The present paper has the objective to present comparisons of the considered computational approaches. It was found that the best agreement with the exact line-by-line calculations of Fels and Schwarzkopf (1981) could be obtained by making use of a new Doppler band model which is described in the appendix of the paper.

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

PubMed

Baskakov, O I; Civis, S; Kawaguchi, K

2005-03-15

In the 2500-8500 cm(-1) region several strong emission bands of (40)ArH 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 (40)ArH were measured and assigned in the 6060 and 3770 cm(-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 (Q)Q(f(3)e) 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 (Q)Q(f(3)e) form branch of the 1-1 band were analyzed.

MODIS On-Orbit Thermal Emissive Bands Lifetime Performance

NASA Technical Reports Server (NTRS)

Madhavan, Sriharsha; Xiong, Xiaoxiong

2016-01-01

MODerate resolution Imaging Spectroradiometer (MODIS), a leading heritage sensor in the fleet of Earth Observing System for the National Aeronautics and Space Administration (NASA) is in space orbit on two spacecrafts. They are the Terra (T) and Aqua (A) platforms. Both instruments have successfully continued to operate beyond the 6 year design life time, with the T-MODIS currently functional beyond 15 years and the A-MODIS operating beyond 13 years respectively. The MODIS sensor characteristics include a spectral coverage from 0.41 micron 14.4 micron, of which wavelengths ranging from 3.7 micron 14. 4 micron cover the thermal infrared region also referred to as the Thermal Emissive Bands (TEBs). The TEBs is calibrated using a v-grooved BlackBody (BB) whose temperature measurements are traceable to the National Institute of Standards and Technology temperature scales. The TEBs calibration based on the onboard BB is extremely important for its high radiometric fidelity. In this paper, we provide a complete characterization of the lifetime instrument performance of both MODIS instruments in terms of the sensor gain, the Noise Equivalent difference Temperature, key instrument telemetry such as the BB lifetime trends, the instrument temperature trends, the Cold Focal Plane telemetry and finally, the total assessed calibration uncertainty of the TEBs.

MODIS on-orbit thermal emissive bands lifetime performance

NASA Astrophysics Data System (ADS)

Madhavan, Sriharsha; Wu, Aisheng; Chen, Na; Xiong, Xiaoxiong

2016-05-01

MODerate resolution Imaging Spectroradiometer (MODIS), a leading heritage sensor in the fleet of Earth Observing System for the National Aeronautics and Space Administration (NASA) is in space orbit on two spacecrafts. They are the Terra (T) and Aqua (A) platforms. Both instruments have successfully continued to operate beyond the 6 year design life time, with the T-MODIS currently functional beyond 15 years and the A-MODIS operating beyond 13 years respectively. The MODIS sensor characteristics include a spectral coverage from 0.41 μm - 14.4 μm, of which wavelengths ranging from 3.7 μm - 14. 4 μm cover the thermal infrared region also referred to as the Thermal Emissive Bands (TEBs). The TEBs is calibrated using a v-grooved BlackBody (BB) whose temperature measurements are traceable to the National Institute of Standards and Technology temperature scales. The TEBs calibration based on the onboard BB is extremely important for its high radiometric fidelity. In this paper, we provide a complete characterization of the lifetime instrument performance of both MODIS instruments in terms of the sensor gain, the Noise Equivalent difference Temperature, key instrument telemetry such as the BB lifetime trends, the instrument temperature trends, the Cold Focal Plane telemetry and finally, the total assessed calibration uncertainty of the TEBs.

Coexistence of strongly and weakly confined energy levels in (Cd,Zn)Se quantum dots: Tailoring the near-band-edge and defect-levels for white light emission

NASA Astrophysics Data System (ADS)

Das, Tapan Kumar; Ilaiyaraja, P.; Sudakar, C.

2017-05-01

We demonstrate white light emission (WLE) from (Cd,Zn)Se system, which is a composite of Zn alloyed CdSe quantum dot and ZnSe-amorphous (ZnSe-a) phase. Detailed structural and photoluminescence emission studies on pure CdSe and (Cd,Zn)Se show cubic zinc blende structure in the size range of 2.5 to 5 nm. (Cd,Zn)Se quantum dots (QDs) also have a significant fraction of ZnSe-a phase. The near-band-edge green-emission in crystalline CdSe and (Cd,Zn)Se is tunable between 500 to 600 nm. The (Cd,Zn)Se system also exhibits a broad, deep defect level (DL) red-emission in the range 600 to 750 nm and a sharp ZnSe near-band-edge blue-emission (ZS-NBE) between 445 to 465 nm. While DL and CdSe near-band-edge (CS-NBE) emissions significantly shift with the size of QD due to strong confinement effect, the ZS-NBE show minimal change in peak position indicating a weak confinement effect. The intensities of ZS-NBE and DL emissions also exhibit a strong dependence on the QD size. A gamut of emission colors is obtained by combining the CS-NBE with the ZS-NBE emission and broad DL emission in (Cd,Zn)Se system. Interestingly, we find the convergence of Commission Internationale de l'Eclairage (CIE) coordinates towards the white light with increasing Zn concentration in CdSe. We demonstrate by combining these three emissions in a proper weight ratio WLE can be achieved. Cd1-yZnySe (y = 0. 5; QD size ˜4.9 nm) alloy with a maximum quantum yield of 57% exhibits CIE coordinates of (0.39, 0.4), color rendering index (CRI) of 82, correlated color temperature (CCT) of 3922 K, and Duv of 0.0078 which is very promising for white light applications.

Yellow fever: epidemiology and prevention.

PubMed

Barnett, Elizabeth D

2007-03-15

Yellow fever continues to occur in regions of Africa and South America, despite the availability of effective vaccines. Recently, some cases of severe neurologic disease and multiorgan system disease have been described in individuals who received yellow fever vaccine. These events have focused attention on the need to define criteria for judicious use of yellow fever vaccine and to describe the spectrum of adverse events that may be associated with yellow fever vaccine. Describing host factors that would increase risk of these events and identifying potential treatment modalities for yellow fever and yellow fever vaccine-associated adverse events are subjects of intense investigation.

Development of Yellow Sand Image Products Using Infrared Brightness Temperature Difference Method

NASA Astrophysics Data System (ADS)

Ha, J.; Kim, J.; Kwak, M.; Ha, K.

2007-12-01

A technique for detection of airborne yellow sand dust using meteorological satellite has been developed from various bands from ultraviolet to infrared channels. Among them, Infrared (IR) channels have an advantage of detecting aerosols over high reflecting surface as well as during nighttime. There had been suggestion of using brightness temperature difference (BTD) between 11 and 12¥ìm. We have found that the technique is highly depends on surface temperature, emissivity, and zenith angle, which results in changing the threshold of BTD. In order to overcome these problems, we have constructed the background brightness temperature threshold of BTD and then aerosol index (AI) has been determined from subtracting the background threshold from BTD of our interested scene. Along with this, we utilized high temporal coverage of geostationary satellite, MTSAT, to improve the reliability of the determined AI signal. The products have been evaluated by comparing the forecasted wind field with the movement fiend of AI. The statistical score test illustrates that this newly developed algorithm produces a promising result for detecting mineral dust by reducing the errors with respect to the current BTD method.

Earth limb views with greenish bands of airglow during STS-99

NASA Image and Video Library

2000-04-06

STS099-355-024 (11-22 February 2000) -- Two separate atmospheric optical phenomena appear in this 35mm photograph captured from the Space Shuttle Endeavour. The thin greenish band above the horizon is airglow; radiation emitted by the atmosphere from a layer about 30-kilometers thick and about 100-kilometers' altitude. The predominant emission in airglow is the green 5577-Angstrom wavelength emission from atomic oxygen atoms, which is also the predominant emission from the aurora. A yellow-orange color is also seen in airglow, which is the emission of the 5800-Angstrom wavelength from sodium atoms. Airglow is always present in the atmosphere; it results from the recombination of molecules that have been broken apart by solar radiation during the day. But airglow is so faint that it can only be seen at night by looking "edge on" at the emission layer, such as the view that astronauts have in Earth orbit. The other phenomenon in the photo appears to be a faint, diffuse red aurora. Red aurora occur from about 200 kilometers to as high as 500 kilometers altitude only in the auroral zones at polar latitudes. They are caused by the emission of 6300- Angstrom wavelength light from oxygen atoms that have been raised to a higher energy level (excited) by collisions with energetic electrons pouring down from the Earth's magnetosphere. The light is emitted when the atoms return to their original unexcited state. With the red light so faint in this picture, scientists are led to believe that the flux density of incoming electrons was small. Also, since there is no green aurora below the red, that indicates that the energy of the incoming electrons was low - higher energy electrons would penetrate deeper into the atmosphere where the green aurora is energized.

Yellow light generation by frequency doubling of a fiber oscillator

NASA Astrophysics Data System (ADS)

Bacher, Christoph; Oliveira, Ricardo; Nogueira, Rogério N.; Romano, Valerio; Ryser, Manuel

2016-04-01

Laser sources with light-emission in the yellow spectral range around 577nm are very favorable for a variety of applications. These include applications in astronomy, in ophthalmology or in quantum optics. The generation and amplification of 1154 nm light is not straight forward when using Yb-doped optical fibers, since lasing occurs preferentially around the gain-maximum of 1030 nm. We generate the radiation within a fiber Bragg grating (FBG) based cavity and focused on reducing the amplified spontaneous emission (ASE). After the cavity, the output is frequency doubled to 577nm by using a second harmonic crystal.

Yellow band disease compromises the reproductive output of the Caribbean reef-building coral Montastraea faveolata (Anthozoa, Scleractinia).

PubMed

Weil, Ernesto; Cróquer, Aldo; Urreiztieta, Isabel

2009-11-16

Sexual reproduction is critical to coral population dynamics and the long-term regeneration of coral reefs. Bleaching, disease, and/or anthropogenic-induced tissue/colony loss reduce reproductive output. This is the first attempt to explore the effect of a biotic disease on the reproduction of scleractinian corals. The study aimed to assess the effect of yellow band disease (YBD) on the reproduction of the important Caribbean reef-builder Montastraea faveolata. Tissue samples were collected from diseased, transition, and healthy-looking areas in each of 5 infected colonies and from 5 healthy controls in southwest Puerto Rico. The effect of disease-induced mortality was assessed by collecting samples from the edge and center of surviving small and large, healthy-looking tissue patches from large, previously infected tagged colonies. Fecundity was significantly lower in disease lesions compared to transition and healthy-looking tissues and the controls (99% fewer eggs). Fecundity in transition areas was significantly lower (50%) than in healthy-looking tissues in diseased colonies, which had 23% lower fecundity than control tissues. Although this fecundity drop was not statistically significant, it could indicate a systemic effect of YBD across the colony. Large and small patches had 64 and 84% fewer eggs than controls, respectively, and edge polyps had 97% fewer eggs than those in central control areas. Field observations of the spawning behavior of each tissue area corroborated the histological results. Our results indicate that YBD significantly compromises the reproductive output of M. faveolata, potentially reducing the fitness and consequently, the recovery of this important reef-building species on Caribbean coral reefs.

Performance and emission analysis on blends of diesel, restaurant yellow grease and n-pentanol in direct-injection diesel engine.

PubMed

Ravikumar, J; Saravanan, S

2017-02-01

Yellow grease from restaurants is typically waste cooking oil (WCO) free from suspended food particles with free fatty acid (FFA) content less than 15%. This study proposes an approach to formulate a renewable, eco-friendly fuel by recycling WCO with diesel (D) and n-pentanol (P) to improve fuel-spray characteristics. Three ternary blends (D50-WCO45-P5, D50-WCO40-P10 and D50-WCO30-P20) were selected based on the stability tests and prepared with an objective to substitute diesel by 50% with up to 45% recycled component (WCO) and up to 20% bio-component (n-pentanol) by volume. The fuel properties of these ternary blends were measured and compared. The emission impacts of these blends on a diesel engine were analysed in comparison with diesel and D50-WCO50 (50% of diesel + 50% of WCO) under naturally articulated and EGR (exhaust gas recirculation) approaches. Doping of n-pentanol showed improved fuel properties when compared to D50-WCO50. Viscosity is reduced up to 45%. Cetane number and density were comparable to that of diesel. Addition of n-pentanol to D50-WCO50 presented improved brake specific fuel consumption (BSFC) for all ternary blends. Brake thermal efficiency (BTE) of D50-WCO30-P20 blend is comparable to diesel due to improved atomization. Smoke opacity reduced, HC emissions increased and CO emissions remained unchanged with doping n-pentanol in the WCO. NOx emission increases with increase in n-pentanol and remained lower than diesel and all load conditions. However, NOx can be decreased by up to threefold using EGR. By adopting this approach, WCO can be effectively reused as a clean energy source by negating environmental hazards before and after its use in diesel engines, instead of being dumped into sewers and landfills.

47 CFR 90.1323 - Emission limits.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Emission limits. 90.1323 Section 90.1323... MOBILE RADIO SERVICES Wireless Broadband Services in the 3650-3700 MHz Band § 90.1323 Emission limits. (a) The power of any emission outside a licensee's frequency band(s) of operation shall be attenuated...

Near-midnight observations of nitric oxide delta- and gamma-band chemiluminescence

NASA Technical Reports Server (NTRS)

Tennyson, P. D.; Feldman, P. D.; Hartig, G. F.; Henry, R. C.

1986-01-01

Chemiluminescent nightglow emission of the nitric oxide delta and gamma bands was measured from a sounding rocket launched on April 27, 1981, near local midnight. The integrated band emission rates for this near zenith observation above 205 km were less than 10 Rayleighs. The solar zenith angle was 127 deg. The branching ratio from the C2Pi state to the A2Sigma(+) state of NO was determined from comparison of the total emission rate of the delta band system to that of the gamma band system and found to be 0.30 + or - 0.06. The branching ratios within each of the band systems were found to be consistent with previous theoretical and experimental determinations. The vertical atomic nitrogen distribution, derived with the use of a model atmosphere, was found to have a peak density of 2.0 x 10 to the 7th atoms/cu cm at an altitude of 205 km. The analysis of these data indicate the presence of residual NO emission above 270 km at local midnight on the order of 1 Rayleigh of total band emission.

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

NASA Technical Reports Server (NTRS)

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

2012-01-01

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.

NEAR-INFRARED THERMAL EMISSION FROM TrES-3b: A Ks-BAND DETECTION AND AN H-BAND UPPER LIMIT ON THE DEPTH OF THE SECONDARY ECLIPSE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Croll, Bryce; Jayawardhana, Ray; Fortney, Jonathan J.

2010-08-01

We present H- and Ks-band photometry bracketing the secondary eclipse of the hot Jupiter TrES-3b using the Wide-field Infrared Camera on the Canada-France-Hawaii Telescope. We detect the secondary eclipse of TrES-3b with a depth of 0.133{sup +0.018}{sub -0.016}% in the Ks band (8{sigma})-a result that is in sharp contrast to the eclipse depth reported by de Mooij and Snellen. We do not detect its thermal emission in the H band, but place a 3{sigma} limit of 0.051% on the depth of the secondary eclipse in this band. A secondary eclipse of this depth in Ks requires very efficient day-to-nightside redistributionmore » of heat and nearly isotropic reradiation, a conclusion that is in agreement with longer wavelength, mid-infrared Spitzer observations. Our 3{sigma} upper limit on the depth of our H-band secondary eclipse also argues for very efficient redistribution of heat and suggests that the atmospheric layer probed by these observations may be well homogenized. However, our H-band upper limit is so constraining that it suggests the possibility of a temperature inversion at depth, or an absorbing molecule, such as methane, that further depresses the emitted flux at this wavelength. The combination of our near-infrared measurements and those obtained with Spitzer suggests that TrES-3b displays a near-isothermal dayside atmospheric temperature structure, whose spectrum is well approximated by a blackbody. We emphasize that our strict H-band limit is in stark disagreement with the best-fit atmospheric model that results from longer wavelength observations only, thus highlighting the importance of near-infrared observations at multiple wavelengths, in addition to those returned by Spitzer in the mid-infrared, to facilitate a comprehensive understanding of the energy budgets of transiting exoplanets.« less

Room temperature direct band gap emission characteristics of surfactant mediated grown compressively strained Ge films

NASA Astrophysics Data System (ADS)

Katiyar, Ajit K.; Grimm, Andreas; Bar, R.; Schmidt, Jan; Wietler, Tobias; Joerg Osten, H.; Ray, Samit K.

2016-10-01

Compressively strained Ge films have been grown on relaxed Si0.45Ge0.55 virtual substrates using molecular beam epitaxy in the presence of Sb as a surfactant. Structural characterization has shown that films grown in the presence of surfactant exhibit very smooth surfaces with a relatively higher strain value in comparison to those grown without any surfactant. The variation of strain with increasing Ge layer thickness was analyzed using Raman spectroscopy. The strain is found to be reduced with increasing film thickness due to the onset of island nucleation following Stranski-Krastanov growth mechanism. No phonon assisted direct band gap photoluminescence from compressively strained Ge films grown on relaxed Si0.45Ge0.55 has been achieved up to room temperature. Excitation power and temperature dependent photoluminescence have been studied in details to investigate the origin of different emission sub-bands.

Investigation of the normal spectral band emissivity characteristic within 7.5 to 13 μm for Molybdenum between 100 and 500 °C

NASA Astrophysics Data System (ADS)

Zhang, Yan; Zhang, Yuzhong; Lu, Rongsheng; Shu, Shuangbao; Lang, Xianli; Yang, Lei

2018-01-01

Molybdenum (Mo) is an important material to construct the first wall for the Experimental Advanced Superconducting Tokamak (EAST). The real-time monitoring of temperature distribution of the first wall based on radiation thermometry is essential to guarantee the stable operation of EAST. So, it is especially important for the acquisition of emissivity property of Mo. In this work, a self-designed emissivity measurement apparatus is developed, and the relationship between the normal infrared spectral band (7.5-13 μm) emissivity of Mo against the temperature and surface roughness of material samples is experimentally investigated under the vacuum condition over the temperature ranging from 100 °C to 500 °C. Moreover, the dependence of spectral band emissivity of Mo exposed to air on the heating-duration time at a given elevated temperature is also studied. The emissivity measurement apparatus is mainly composed of a high temperature furnace and a radiation thermometer as well as a benchmark blackbody furnace. The radiation thermometer is firstly calibrated against the blackbody furnace by means of the multi-temperature methods. And then the temperature of the sample is simultaneously measured by the two highly accurate S-type thermocouples and the radiation thermometer. Finally the emissivity value of the sample is calculated based on the direct radiometric method. The developed emissivity measurement method and experimental results obtained in this work may be helpful to understand the work state the EAST and to use of Mo as an emissivity reference.

Study on the Spectral Mixing Model for Mineral Pigments Based on Derivative of Ratio Spectroscopy-Take Vermilion and Stone Yellow for Example

NASA Astrophysics Data System (ADS)

Zhao, H.; Hao, Y.; Liu, X.; Hou, M.; Zhao, X.

2018-04-01

Hyperspectral remote sensing is a completely non-invasive technology for measurement of cultural relics, and has been successfully applied in identification and analysis of pigments of Chinese historical paintings. Although the phenomenon of mixing pigments is very usual in Chinese historical paintings, the quantitative analysis of the mixing pigments in the ancient paintings is still unsolved. In this research, we took two typical mineral pigments, vermilion and stone yellow as example, made precisely mixed samples using these two kinds of pigments, and measured their spectra in the laboratory. For the mixing spectra, both fully constrained least square (FCLS) method and derivative of ratio spectroscopy (DRS) were performed. Experimental results showed that the mixing spectra of vermilion and stone yellow had strong nonlinear mixing characteristics, but at some bands linear unmixing could also achieve satisfactory results. DRS using strong linear bands can reach much higher accuracy than that of FCLS using full bands.

Spontaneous emission inhibition of telecom-band quantum disks inside single nanowire on different substrates.

PubMed

Birowosuto, M D; Zhang, G; Yokoo, A; Takiguchi, M; Notomi, M

2014-05-19

We investigate the inhibited spontaneous emission of telecom-band InAs quantum disks (Qdisks) in InP nanowires (NWs). We have evaluated how the inhibition is affected by different disk diameter and thickness. We also compared the inhibition in standing InP NWs and those NWs laying on silica (SiO(2)), and silicon (Si) substrates. We found that the inhibition is altered when we put the NW on the high-refractive-index materials of Si. Experimentally, the inhibition factor ζ of the Qdisk emission at 1,500 nm decreases from 4.6 to 2.5 for NW on SiO(2) and Si substrates, respectively. Those inhibitions are even much smaller than that of 6.4 of the standing NW. The inhibition factors well agree with those calculated from the coupling of the Qdisk to the fundamental guided mode and the continuum of radiative modes. Our observation can be useful for the integration of the NW as light sources in the photonic nanodevices.

Beyond the Band Function Paradigm : a New Model for GRB Prompt Emission and Possible Impact in Cosmology

NASA Astrophysics Data System (ADS)

Guiriec, Sylvain

Gamma Ray Bursts (GRBs) are the most violent phenomenons in the Universe. They are associated with the birth of stellar mass black holes either from the collapse of hypermassive stars or the merger of compact objects. The Fireball model is the most popular scenario to explain GRBs. In this theoretical framework, GRB central engines release collimated, bipolar and highly relativistic jets mainly composed of electrons, positrons, photons, and a small amount of baryons. During the first phase of the Fireball model, charged particles are accelerated and release non-thermal radiations. The Fireball model also predicts a thermal like component coming from the jet photosphere. This first phase would be responsible for the GRB prompt emission observed by gamma ray telescopes such as Fermi/GBM in the keV-MeV energy range and which is the only phase discussed in this talk. Until now, GRB prompt emission spectra were considered as adequately fitted with the empirical Band function, which is a smoothly broken power law. However, its parameters are very often incompatible with the Fireball model predictions for both the thermal and non-thermal components. We will see that observation with the Fermi Gamma Ray Space Telescope break the paradigm of the Band function and that deviations from this function exists in many GRBs. Those deviations are adequately fitted with an additional thermal-like component -that we consider as the jet photosphere- and/or an additional power law. Importantly, with the three components together, theory and observations are much more in agreement. We will also see how this new model for prompt emission spectra may have an impact beyond the physics of GRBs. Indeed, this work may confirm a relation between the hardness of the GRB prompt emission and its luminosity which may be used to scale GRBs as standard-like candles for use in cosmology.

Fabrication of a white electroluminescent device based on bilayered yellow and blue quantum dots.

PubMed

Kim, Jong-Hoon; Lee, Ki-Heon; Kang, Hee-Don; Park, Byoungnam; Hwang, Jun Yeon; Jang, Ho Seong; Do, Young Rag; Yang, Heesun

2015-03-12

Until now most work on colloidal quantum dot-light-emitting diodes (QLEDs) has been focused on the improvement of the electroluminescent (EL) performance of monochromatic devices, and multi-colored white QLEDs comprising more than one type of QD emitter have been rarely investigated. To demonstrate a white EL as a result of color mixing between blue and yellow, herein a unique combination of two dissimilar QDs of blue- CdZnS/ZnS plus a yellow-emitting Cu-In-S (CIS)/ZnS is used for the formation of the emitting layer (EML) of a multilayered QLED. First, the QLED consisting of a single EML randomly mixed with two QDs is fabricated, however, its EL is dominated by blue emission with the contribution of yellow emission substantially weaker. Thus, another EML configuration is devised in the form of a QD bilayer with two stacking sequences of CdZnS/ZnS//CIS/ZnS QD and vice versa. The QLED with the former stacking sequence shows an overwhelming contribution of blue EL, similar to the mixed QD EML-based device. Upon applying the oppositely stacked QD bilayer of CIS/ZnS//CdZnS/ZnS, however, a bicolored white EL can be successfully achieved by means of the effective extension of the radiative excitonic recombination zone throughout both QD EML regions. Such QD EML configuration-dependent EL results, which are discussed primarily using the proposed device energy level diagram, strongly suggest that the positional design of individual QD emitters is a critical factor for the realization of multicolored, white emissive devices.

Detector Noise Characterization and Performance of MODIS Thermal Emissive Bands

NASA Technical Reports Server (NTRS)

Xiong, X.; Wu, A.; Chen, N.; Chiang, K.; Xiong, S.; Wenny, B.; Barnes, W. L.

2007-01-01

MODIS has 16 thermal emissive bands, a total of 160 individual detectors (10 for each spectral bands), located on the two cold focal plane assemblies (CFPA). MODIS TEB detectors were fully characterized pre-launch in a thermal vacuum (TV) environment using a NIST traceable blackbody calibration source (BCS) with temperatures ranging from 170 to 340K. On-orbit the TEB detectors are calibrated using an on-board blackbody (BB) on a scan-by-scan basis. For nominal on-orbit operation, the on-board BB temperature is typically controlled at 285K for Aqua MODIS and 290K for Terra MODIS. For the MODIS TEB calibration, each detector's noise equivalent temperature difference (NEdT) is often used to assess its performance and this parameter is a major contributor to the calibration uncertainty. Because of its impact on sensor calibration and data product quality, each MODIS TEB detector's NEdT is monitored on a daily basis at a fixed BB temperature and completely characterized on a regular basis at a number of BB temperatures. In this paper, we describe MODIS on-orbit TEB NEdT characterization activities, approaches, and results. We compare both pre-launch and on-orbit performance with sensor design specification and examine detector noise characterization impact on the calibration uncertainty. To date, 135 TEB detectors (out of a total of 160 detectors) in Terra MODIS (launched in December 1999) and 158 in Aqua MODIS (launched in May 2002) continue to perform with their NEdT below (or better than) their design specifications. A complete summary of all TEB noisy detectors, identified both pre-launch and on-orbit, is provided.

Study on Remote Sensing Image Characteristics of Ecological Land: Case Study of Original Ecological Land in the Yellow River Delta

NASA Astrophysics Data System (ADS)

An, G. Q.

2018-04-01

Takes the Yellow River Delta as an example, this paper studies the characteristics of remote sensing imagery with dominant ecological functional land use types, compares the advantages and disadvantages of different image in interpreting ecological land use, and uses research results to analyse the changing trend of ecological land in the study area in the past 30 years. The main methods include multi-period, different sensor images and different seasonal spectral curves, vegetation index, GIS and data analysis methods. The results show that the main ecological land in the Yellow River Delta included coastal beaches, saline-alkaline lands, and water bodies. These lands have relatively distinct spectral and texture features. The spectral features along the beach show characteristics of absorption in the green band and reflection in the red band. This feature is less affected by the acquisition year, season, and sensor type. Saline-alkali land due to the influence of some saline-alkaline-tolerant plants such as alkali tent, Tamarix and other vegetation, the spectral characteristics have a certain seasonal changes, winter and spring NDVI index is less than the summer and autumn vegetation index. The spectral characteristics of a water body generally decrease rapidly with increasing wavelength, and the reflectance in the red band increases with increasing sediment concentration. In conclusion, according to the spectral characteristics and image texture features of the ecological land in the Yellow River Delta, the accuracy of image interpretation of such ecological land can be improved.

Broad-band emission properties of central engine powered supernova ejecta interacting with a circumstellar medium

NASA Astrophysics Data System (ADS)

Suzuki, Akihiro; Maeda, Keiichi

2018-04-01

We investigate broad-band emission from supernova ejecta powered by a relativistic wind from a central compact object. A recent two-dimensional hydrodynamic simulation studying the dynamical evolution of supernova ejecta with a central energy source has revealed that outermost layers of the ejecta are accelerated to mildly relativistic velocities because of the breakout of a hot bubble driven by the energy injection. The outermost layers decelerate as they sweep a circumstellar medium surrounding the ejecta, leading to the formation of the forward and reverse shocks propagating in the circumstellar medium and the ejecta. While the ejecta continue to release the internal energy as thermal emission from the photosphere, the energy dissipation at the forward and reverse shock fronts gives rise to non-thermal emission. We calculate light curves and spectral energy distributions of thermal and non-thermal emission from central engine powered supernova ejecta embedded in a steady stellar wind with typical mass loss rates for massive stars. The light curves are compared with currently available radio and X-ray observations of hydrogen-poor superluminous supernovae, as well as the two well-studied broad-lined Ic supernovae, 1998bw and 2009bb, which exhibit bright radio emission indicating central engine activities. We point out that upper limits on radio luminosities of nearby superluminous supernovae may indicate the injected energy is mainly converted to thermal radiation rather than creating mildly relativistic flows owing to photon diffusion time scales comparable to the injection time scale.

Dual-Polarization Observations of Slowly Varying Solar Emissions from a Mobile X-Band Radar

PubMed Central

Gabella, Marco; Leuenberger, Andreas

2017-01-01

The radio noise that comes from the Sun has been reported in literature as a reference signal to check the quality of dual-polarization weather radar receivers for the S-band and C-band. In most cases, the focus was on relative calibration: horizontal and vertical polarizations were evaluated versus the reference signal mainly in terms of standard deviation of the difference. This means that the investigated radar receivers were able to reproduce the slowly varying component of the microwave signal emitted by the Sun. A novel method, aimed at the absolute calibration of dual-polarization receivers, has recently been presented and applied for the C-band. This method requires the antenna beam axis to be pointed towards the center of the Sun for less than a minute. Standard deviations of the difference as low as 0.1 dB have been found for the Swiss radars. As far as the absolute calibration is concerned, the average differences were of the order of −0.6 dB (after noise subtraction). The method has been implemented on a mobile, X-band radar, and this paper presents the successful results that were obtained during the 2016 field campaign in Payerne (Switzerland). Despite a relatively poor Sun-to-Noise ratio, the “small” (~0.4 dB) amplitude of the slowly varying emission was captured and reproduced; the standard deviation of the difference between the radar and the reference was ~0.2 dB. The absolute calibration of the vertical and horizontal receivers was satisfactory. After the noise subtraction and atmospheric correction a, the mean difference was close to 0 dB. PMID:28531164

Dual-Polarization Observations of Slowly Varying Solar Emissions from a Mobile X-Band Radar.

PubMed

Gabella, Marco; Leuenberger, Andreas

2017-05-22

The radio noise that comes from the Sun has been reported in literature as a reference signal to check the quality of dual-polarization weather radar receivers for the S-band and C-band. In most cases, the focus was on relative calibration: horizontal and vertical polarizations were evaluated versus the reference signal mainly in terms of standard deviation of the difference. This means that the investigated radar receivers were able to reproduce the slowly varying component of the microwave signal emitted by the Sun. A novel method, aimed at the absolute calibration of dual-polarization receivers, has recently been presented and applied for the C-band. This method requires the antenna beam axis to be pointed towards the center of the Sun for less than a minute. Standard deviations of the difference as low as 0.1 dB have been found for the Swiss radars. As far as the absolute calibration is concerned, the average differences were of the order of -0.6 dB (after noise subtraction). The method has been implemented on a mobile, X-band radar, and this paper presents the successful results that were obtained during the 2016 field campaign in Payerne (Switzerland). Despite a relatively poor Sun-to-Noise ratio, the "small" (~0.4 dB) amplitude of the slowly varying emission was captured and reproduced; the standard deviation of the difference between the radar and the reference was ~0.2 dB. The absolute calibration of the vertical and horizontal receivers was satisfactory. After the noise subtraction and atmospheric correction a, the mean difference was close to 0 dB.

Io's Sodium Cloud (Green-yellow Filter)

NASA Technical Reports Server (NTRS)

1997-01-01

This image of Jupiter's moon Io and its surrounding sky is shown in false color. North is at the top, and east is to the right. Most of Io's visible surface is in shadow, though one can see part of a white crescent on its western side. This crescent is being illuminated mostly by 'Jupitershine' (i.e. sunlight reflected off Jupiter).

The striking burst of white light near Io's eastern equatorial edge is sunlight being scattered by the plume of the volcano Prometheus. Prometheus lies just beyond the visible edge of the moon on Io's far side. Its plume extends about 100 kilometers above the surface, and is being hit by sunlight just a little east of Io's eastern edge.

Scattered light from Prometheus' plume and Io's lit crescent also contribute to the diffuse yellowish emission which appears throughout much of the sky. However, much of this emission comes from Io's Sodium Cloud: sodium atoms within Io's extensive material halo are scattering sunlight at the yellow wavelength of about 589 nanometers.

This image was taken at 5 hours 30 minutes Universal Time on Nov. 9, 1996 through the green-yellow filter of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft. Galileo was then in Jupiter's shadow, and located about 2.3 million kilometers (about 32 Jovian radii) from both Jupiter and Io.

The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington D.C. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at: http://galileo.jpl.nasa.gov.

Visible sub-band gap photoelectron emission from nitrogen doped and undoped polycrystalline diamond films

NASA Astrophysics Data System (ADS)

Elfimchev, S.; Chandran, M.; Akhvlediani, R.; Hoffman, A.

2017-07-01

In this study the origin of visible sub-band gap photoelectron emission (PEE) from polycrystalline diamond films is investigated. The PEE yields as a function of temperature were studied in the wavelengths range of 360-520 nm. Based on the comparison of electron emission yields from diamond films deposited on silicon and molybdenum substrates, with different thicknesses and nitrogen doping levels, we suggested that photoelectrons are generated from nitrogen related centers in diamond. Our results show that diamond film thickness and substrate material have no significant influence on the PEE yield. We found that nanocrystalline diamond films have low electron emission yields, compared to microcrystalline diamond, due to the presence of high amount of defects in the former, which trap excited electrons before escaping into the vacuum. However, the low PEE yield of nanocrystalline diamond films was found to increase with temperature. The phenomenon was explained by the trap assisted photon enhanced thermionic emission (ta-PETE) model. According to the ta-PETE model, photoelectrons are trapped by shallow traps, followed by thermal excitation at elevated temperatures and escape into the vacuum. Activation energies of trap levels were estimated for undoped nanocrystalline, undoped microcrystalline and N-doped diamond films using the Richardson-Dushman equation, which gives 0.13, 0.39 and 0.04 eV, respectively. Such low activation energy of trap levels makes the ta-PETE process very effective at elevated temperatures.

Generation of Multi-band Chorus by Lower Band Cascade in the Earth's Magnetosphere

NASA Astrophysics Data System (ADS)

Gao, X.; Lu, Q.; Chen, L.; Bortnik, J.; Li, W.; Wang, S.

2016-12-01

Chorus waves are intense electromagnetic whistler-mode emissions in the magnetosphere, typically falling into two distinct frequency bands: a lower band (0.1-0.5fce) and an upper band (0.5-0.8fce) with a power gap at about 0.5fce. In this letter, with the THEMIS satellite, we observed two special chorus events, which are called as multi-band chorus because upper band chorus is located at harmonics of lower band chorus. We propose a new potential generation mechanism for multi-band chorus, which is called as lower band cascade. In this scenario, a density mode with a frequency equal to that of lower band chorus is caused by the ponderomotive effect (inhomogeneity of the electric amplitude) along the wave vector, and then upper band chorus with the frequency twice that of lower band chorus is generated through wave-wave couplings between lower band chorus and the density mode. The mechanism provides a new insight into the evolution of whistler-mode chorus in the Earth's magnetosphere.

Optical absorption and emission bands of Tm 3+ ions in calcium niobium gallium garnet crystal

NASA Astrophysics Data System (ADS)

Tsuboi, Taiju; Tanigawa, Masayuki; Shimamura, Kiyoshi

2000-12-01

Absorption spectra of Tm 3+ ions in Ca 3Nb 1.6875Ga 3.1875O 12 (CNGG) crystal have been investigated at various temperatures between 15 and 296 K. Luminescence spectra in a spectral region of 400-1750 nm are investigated under excitation into various excited states of Tm 3+ and the conduction band of CNGG at room temperature. The absorption and emission bands of Tm 3+ in CNGG are observed to be broader than those observed in other Tm 3+-doped crystals such as LiNbO 3. This is due to the disordered structure of CNGG. From the temperature dependence of absorption spectra, five Stark levels are derived for the 3H 6 ground state. The highest Stark level is found to be 351 cm -1 above the ground level. It is suggested that the low efficiency of the 2.02 μm lasing at room temperature is due to the narrow splitting of the Stark levels.

Io's Sodium Cloud (Clear Filter and Green-Yellow Filter with Intensity Contours)

NASA Technical Reports Server (NTRS)

1997-01-01

This picture contains two images of Jupiter's moon Io and its surrounding sky. The original frame was exposed twice, once through a clear filter and once through a green-yellow filter. The camera pointed in slightly different directions for the two exposures, placing a clear filter image of Io in the top half of the frame, and a green-yellow filter image of Io in the bottom half of the frame. This picture shows the entire original frame with the addition of intensity contours and false color. East is to the right.

Most of Io's visible surface is in shadow, though part of a white crescent can be seen on its western side. This crescent is being illuminated mostly by 'Jupitershine' (i.e., sunlight reflected off Jupiter). Near Io's eastern equatorial edge is a burst of white light which shows up best in the lower image. This sunlight being scattered by the plume of the volcano Prometheus. Prometheus lies just beyond the visible edge of the moon on Io's far side. Its plume extends about 100 kilometers above the surface, and is being hit by sunlight just a little east of Io's eastern edge.

The sky is full of diffuse light, some of which is scattered light from Prometheus' plume and Io's lit crescent (particularly in the half of the frame dominated by the clear filter). However, much of the diffuse emission comes from Io's Sodium Cloud: sodium atoms within Io's extensive material halo are scattering sunlight into both the clear and green-yellow filters at a wavelength of about 589 nanometers.

The intensity contours help to illustrate that: (i) significant diffuse emission is present all the way to the eastern edge of the frame (indeed, the Sodium Cloud is known to extend far beyond that edge); (ii) the diffuse emission exhibits a directional feature at about four o'clock relative to Io's center (similar features have been seen in the Sodium Cloud at greater distances from Io).

The upper image of Io exhibits a roundish white spot in the bottom half of Io

The yellow x paper birch hybrid--a potential substitute for yellow birch on problem sites

Treesearch

Knud E. Clausen

1977-01-01

Yellow x paper birch hybrids and yellow birches with common female parents were compared after 5 growing seasons in an open field. Survival of the hybrids was 91 percent compared with 64 percent for the yellow birch trees. The hybrids were from 25 to 32 percent taller than the yellow birches and had 19-40 percent greater diameter. Because this hybrid not only grows...

Electronic structure descriptor for the discovery of narrow-band red-emitting phosphors

DOE PAGES

Wang, Zhenbin; Chu, Iek -Heng; Zhou, Fei; ...

2016-05-09

Narrow-band red-emitting phosphors are a critical component of phosphor-converted light-emitting diodes for highly efficient illumination-grade lighting. In this work, we report the discovery of a quantitative descriptor for narrow-band Eu 2+-activated emission identified through a comparison of the electronic structures of known narrow-band and broad-band phosphors. We find that a narrow emission bandwidth is characterized by a large splitting of more than 0.1 eV between the two highest Eu 2+ 4 f 7 bands. By incorporating this descriptor in a high-throughput first-principles screening of 2259 nitride compounds, we identify five promising new nitride hosts for Eu 2+-activated red-emitting phosphors thatmore » are predicted to exhibit good chemical stability, thermal quenching resistance, and quantum efficiency, as well as narrow-band emission. Lastly, our findings provide important insights into the emission characteristics of rare-earth activators in phosphor hosts and a general strategy to the discovery of phosphors with a desired emission peak and bandwidth.« less

Electronic structure descriptor for the discovery of narrow-band red-emitting phosphors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhenbin; Chu, Iek -Heng; Zhou, Fei

Narrow-band red-emitting phosphors are a critical component of phosphor-converted light-emitting diodes for highly efficient illumination-grade lighting. In this work, we report the discovery of a quantitative descriptor for narrow-band Eu 2+-activated emission identified through a comparison of the electronic structures of known narrow-band and broad-band phosphors. We find that a narrow emission bandwidth is characterized by a large splitting of more than 0.1 eV between the two highest Eu 2+ 4 f 7 bands. By incorporating this descriptor in a high-throughput first-principles screening of 2259 nitride compounds, we identify five promising new nitride hosts for Eu 2+-activated red-emitting phosphors thatmore » are predicted to exhibit good chemical stability, thermal quenching resistance, and quantum efficiency, as well as narrow-band emission. Lastly, our findings provide important insights into the emission characteristics of rare-earth activators in phosphor hosts and a general strategy to the discovery of phosphors with a desired emission peak and bandwidth.« less

Near band edge photoluminescence of ZnO nanowires: Optimization via surface engineering

NASA Astrophysics Data System (ADS)

Yan, Danhua; Zhang, Wenrui; Cen, Jiajie; Stavitski, Eli; Sadowski, Jerzy T.; Vescovo, Elio; Walter, Andrew; Attenkofer, Klaus; Stacchiola, Darío J.; Liu, Mingzhao

2017-12-01

Zinc oxide (ZnO) nanowire arrays have potential applications for various devices such as ultra-violet light emitting diodes and lasers, where photoluminescence of intense near band edge emission without defect emissions is usually desired. Here, we demonstrate, counter-intuitively, that the near band edge emission may become dominant by introducing certain surface defects to ZnO nanowires via surface engineering. Specifically, near band edge emission (NBE) is effectively enhanced after a low pressure O2 plasma treatment that sputters off surface oxygen species to produce a reduced and oxygen vacancy-rich surface. The effect is attributed to the lowered surface valence band maximum of the reduced ZnO surface that creates an accumulative band bending, which screens the photo-generated minority carriers (holes) from reaching or being trapped by the surface defects.

47 CFR 15.239 - Operation in the band 88-108 MHz.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.239 Operation in the band 88-108 MHz. (a) Emissions from the intentional radiator shall be confined within a band 200 kHz wide centered... the general radiated emission limits in § 15.209. (d) A custom built telemetry intentional radiator...

Flesh color inheritance and gene interactions among canary yellow, pale yellow and red watermelon

USDA-ARS?s Scientific Manuscript database

Two loci, C and i-C were previously reported to determine flesh color between canary yellow and red watermelon. Recently LCYB was found as a color determinant gene for canary yellow (C) and co-dominant CAPS marker was developed to identify canary yellow and red alleles. Another report suggested th...

Beet yellow stunt

USDA-ARS?s Scientific Manuscript database

Beet yellow stunt virus (BYSV) is a potentially destructive yellows-type virus affecting plants in the family Asteraceae. The virus is a member of the genus Closterovirus, family Closteroviridae, and has been found in California and England. Initial symptoms consist of chlorosis of the older leaves,...

Cross-couplings in the elaboration of luminescent bis-terpyridyl iridium complexes: the effect of extended or inhibited conjugation on emission.

PubMed

Leslie, Wendy; Batsanov, Andrei S; Howard, Judith A K; Williams, J A Gareth

2004-02-21

The utility of Suzuki cross-coupling methodology for the in situ elaboration of bromo-functionalised bis-terpyridyl iridium(III) complexes has been explored. The complex [Ir(tpy)(tpy-phi-Br)]3+ [tpy-phi-Br = 4'-(4-bromophenyl)-2,2':6',2''-terpyridine] undergoes palladium-catalysed cross-coupling with aryl boronic acids to yield biaryl-substituted complexes directly. The biphenyl and 4-cyanobiphenyl-substituted products display relatively intense, long-lived (tau > 100 mus) yellow emission in degassed aqueous solution at room temperature, assigned to a 3pi-pi* state. A 4-aminobiphenyl-substituted analogue displays an additional low energy absorbance band, attributed to an intraligand charge-transfer (ILCT) excited state, and is scarcely emissive under the same conditions. The iridium(III) complex of 4'-mesityl-terpyridine is also reported. Its emission is much shorter-lived, with a spectral profile resembling that of unsubstituted [Ir(tpy)2]3+, confirming the need for the attainment of a roughly coplanar geometry for stabilisation of the 3pi-pi* excited state.

Io's Sodium Cloud (Clear and Green-Yellow Filters)

NASA Technical Reports Server (NTRS)

1997-01-01

The green-yellow filter and clear filter images of Io which were released over the past two days were originally exposed on the same frame. The camera pointed in slightly different directions for the two exposures, placing a clear filter image of Io on the top half of the frame, and a green-yellow filter image of Io on the bottom half of the frame. This picture shows that entire original frame in false color, the most intense emission appearing white.

East is to the right. Most of Io's visible surface is in shadow, though one can see part of an illuminated crescent on its western side. The burst of white light near Io's eastern equatorial edge (most distinctive in the green filter image) is sunlight scattered by the plume of the volcano Prometheus.

There is much more bright light near Io in the clear filter image, since that filter's wider wavelength range admits more scattered light from Prometheus' sunlit plume and Io's illuminated crescent. Thus in the clear filter image especially, Prometheus's plume was bright enough to produce several white spikes which extend radially outward from the center of the plume emission. These spikes are artifacts produced by the optics of the camera. Two of the spikes in the clear filter image appear against Io's shadowed surface, and the lower of these is pointing towards a bright round spot. That spot corresponds to thermal emission from the volcano Pele.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siemion, Andrew P. V.; Korpela, Eric; Werthimer, Dan

2013-04-10

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 bandmore » 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.« less

Near band edge photoluminescence of ZnO nanowires: Optimization via surface engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Danhua; Zhang, Wenrui; Cen, Jiajie

Zinc oxide (ZnO) nanowire arrays have potential applications for various devices including ultra-violet light emitting diodes and lasers, where photoluminescence of intense near band edge emission without defect emissions is usually desired. Here, we demonstrate, counter-intuitively, that the near band edge emission may become dominant by introducing certain surface defects to ZnO nanowires via surface engineering. Specifically, near band edge emission (NBE) is effectively enhanced after a low pressure O 2 plasma treatment that sputters off surface oxygen species to produce a reduced and oxygen vacancy-rich surface. The effect is attributed to the lowered surface valence band maximum of themore » reduced ZnO surface that creates an accumulative band bending, which screens the photo-generated minority carriers (holes) from reaching or being trapped by the surface defects.« less

Near band edge photoluminescence of ZnO nanowires: Optimization via surface engineering

DOE PAGES

Yan, Danhua; Zhang, Wenrui; Cen, Jiajie; ...

2017-12-04

Zinc oxide (ZnO) nanowire arrays have potential applications for various devices including ultra-violet light emitting diodes and lasers, where photoluminescence of intense near band edge emission without defect emissions is usually desired. Here, we demonstrate, counter-intuitively, that the near band edge emission may become dominant by introducing certain surface defects to ZnO nanowires via surface engineering. Specifically, near band edge emission (NBE) is effectively enhanced after a low pressure O 2 plasma treatment that sputters off surface oxygen species to produce a reduced and oxygen vacancy-rich surface. The effect is attributed to the lowered surface valence band maximum of themore » reduced ZnO surface that creates an accumulative band bending, which screens the photo-generated minority carriers (holes) from reaching or being trapped by the surface defects.« less

Relations between broad-band linear polarization and Ca II H and K emission in late-type dwarf stars

NASA Technical Reports Server (NTRS)

Huovelin, Juhani; Saar, Steven H.; Tuominen, Ilkka

1988-01-01

Broadband UBV linear polarization data acquired for a sample of late-type dwarfs are compared with contemporaneous measurements of Ca II H and K line core emission. A weighted average of the largest values of the polarization degree is shown to be the best parameter for chromospheric activity diagnosis. The average maximum polarization in the UV is found to increase from late-F to late-G stars. It is noted that polarization in the U band is considerably more sensitive to activity variations than that in the B or V bands. The results indicate that stellar magnetic fields and the resulting saturation in the Zeeman-sensitive absorption lines are the most probably source of linear polarization in late-type main-sequence stars.

Nitrous oxide emissions from yellow brown soil as affected by incorporation of crop residues with different carbon-to-nitrogen ratios: a case study in central China.

PubMed

Lin, Shan; Iqbal, Javed; Hu, Ronggui; Shaaban, Muhammad; Cai, Jianbo; Chen, Xi

2013-08-01

To investigate the influence of crop residues decomposition on nitrous oxide (N2O) emission, a field study was performed with application of crop residues with different C:N ratios in a bare yellow brown soil at the experimental station of Zhangjiachong at Zigui, China. We set up six experimental treatments: no crop residue (CK), rapeseed cake (RC), potato stalk (PS), rice straw (RS), wheat straw (WS), and corn straw (CS). The carbon (C) to nitrogen (N) ratios of these crop residues were 7.5, 32.9, 40.4, 65.7, and 90.9, respectively. Nitrous oxide fluxes were measured using a static closed chamber method. N2O emissions were significantly enhanced by incorporation of crop residues. Cumulative N2O emissions negatively correlated with C:N ratio (R (2) = 0.9821) of the crop residue, but they were positively correlated with average concentrations of dissolved organic carbon and microbial biomass carbon. Nitrogen emission fraction, calculated as N2O-N emissions originated from the crop residues N, positively correlated with C:N ratio of the residues (P < 0.05). Soil temperature did, whereas soil moisture did not, control the residue's induced N2O emissions because a significant correlation (P < 0.01) existed between soil temperature and N2O emissions in all treatments except the control. In contrast, a significant relationship between soil moisture and N2O emissions was found in the control only. Furthermore, N2O emission significantly correlated (P < 0.05) with NO3 (-)-N, and NH4 (+)-N contents from all residue treatments. These results indicate that (1) crop residues with distinct carbon and nitrogen contents can significantly alter soil N2O flux rates; and (2) soil biotic as well as abiotic variables are critical in determining soil-atmospheric N2O emissions after crop residue incorporation into soil.

[Estimating spatiotemporal dynamics of methane emissions from livestock in China].

PubMed

Lin, Yu; Zhang, Wen; Huang, Yao

2011-08-01

Combining Tier 2 method presented in the guidelines of the Intergovernmental Panel on Climate Change (IPCC, 2006) with GIS techniques, a primary estimation of methane emission from livestock in 2004 (including emission from enteric fermentation and manure management system) was made with county-level livestock statistics and 1 km x 1 km raster data. The results indicated that the methane emission from livestock was 12.79 x 10(6) tons totally in China, and 11.64 x 10(6) tons from enteric fermentation and 1.16 x 10(6) tons from manure management. The uncertainties of the methane emission from enteric fermentation and manure management were +/- 35.10% and +/- 14. 58% respectively. The high methane emission was at Yellow River basin, especially in the lower reaches of the Yellow River and the North China Plain. The Southwestern China also can be found with high emission. In accordance with the seasonal temperature changes, the temporal variation of manure management emission was estimated the highest in summer and the lowest in winter.

Nightglow emissions of OH/X 2 pi/ - Comparison of theory and measurements in the /9-3/ band

NASA Technical Reports Server (NTRS)

Frederick, J. E.; Rusch, D. W.; Liu, S. C.

1978-01-01

The visible airglow experiments on the Atmosphere Explorer C and E satellites have viewed the (9-3) band nightglow emission of the excited hydroxyl radical in the lower thermosphere at tropical latitudes. The surface brightnesses observed at similar local times vary by approximately a factor of 2. Comparison of the measurements with time-dependent photochemical calculations shows reasonable agreement and indicates that temporal changes in atmospheric transport processes are the most likely explanation of the nightglow variations.

Insect enemies of yellow-poplar

Treesearch

Denver P. Burns; Denver P. Burns

1970-01-01

Yellow-poplar, like the other desirable hardwoods, is attacked by a variety of insects. However, only four species of insects are considered economically important: the tuliptree scale, the yellow-poplar weevil, the root-collar borer, and the Columbian timber beetle. These are native enemies of yellow-poplar (Liriodendvon tzllipifera L.) wherever the tree grows.

A definitive analytical spectroscopic study of Indian yellow, an ancient pigment used for dating purposes.

PubMed

de Faria, Dalva L A; Edwards, Howell G M; Careaga, Valeria; Walt, Nicholas; Maier, Marta S

2017-02-01

The Raman spectrum of tartrazine has been mistakenly reported as being that of Indian yellow in the literature, which has serious consequences for the identification of this pigment in art works regarding their authentication. Unlike tartrazine, Indian yellow (a natural mixture of the magnesium and calcium salts of euxanthic acid) exhibits in its Raman spectrum a strong fluorescent background when visible excitation is used, however, excitation in the near infrared (1064nm) permitted the observation of the Raman bands from the raw pigment with the main features placed at 1346, 1368, 1425, 1441 and 1626cm -1 . Indian yellow identification was assured by 1 H and 13 C Nuclear Magnetic Resonance characterization and the complete assignment of the proton and carbon resonances was accomplished using heteronuclear single quantum correlation (HSQC), heteronuclear multiple bond correlation (HMBC), nuclear overhauser effect spectroscopy (NOESY) and 1 H- 1 H correlation spectroscopy (COSY). Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and X-ray fluorescence (XRF) analyzes were also conducted on a genuine sample of this historical pigment. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Impact of Antibody Bioconjugation on Emission and Energy Band Profile of CdSeTe/ZnS Quantum Dots

NASA Astrophysics Data System (ADS)

Torchynska, T. V.; Gomez, J. A. Jaramillo; Polupan, G.; Macotela, L. G. Vega

2018-03-01

The variation of the photoluminescence (PL) and Raman scattering spectra of CdSeTe/ZnS quantum dots (QDs) on conjugation to an antibody has been investigated. Two types of CdSeTe/ZnS QD with different emission wavelength (705 nm and 800 nm) were studied comparatively before and after conjugation to anti-pseudorabies virus antibody (AB). Nonconjugated QDs were characterized by Gaussian-type PL bands. PL shifts to higher energy and asymmetric shape of PL bands was detected in PL spectra of bioconjugated QDs. The surface-enhanced Raman scattering effect was exhibited by the bioconjugated CdSeTe/ZnS QDs, indicating that the excitation light used in the Raman study generated electric dipoles in the AB molecules. The optical bandgap of the CdSeTe core was calculated numerically as a function of its radius based on an effective mass approximation model. The energy band diagrams for non- and bioconjugated CdSeTe/ZnS QDs were obtained, revealing a type II quantum well in the CdSeTe core. The calculations show that AB dipoles, excited in the bioconjugated QDs, stimulate a change in the energy band diagram of the QDs that alters the PL spectrum. These results could be useful for improving the sensitivity of QD biosensors.

Annealing effect on the photoluminescence properties of ZnO nanorod array prepared by a PLD-assistant wet chemical method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei Sufeng; Lian Jianshe; Wu Hua, E-mail: weisufeng@gmail.com

2010-11-15

Well-aligned ZnO nanorod arrays were synthesized by a wet chemical method on the glass substrate with ZnO thin film as seed layer prepared by pulsed laser deposition. The effect of annealing temperature on the luminescence characteristics was investigated. As the annealing temperature increased, the photoluminescence properties show a general enhancing tendency. The nanorod array with high ultraviolet emission and negligible visible light emission (designated by the photoluminescence intensity ratio of ultraviolet to visible emission of 66.4) is obtained by annealing the sample at 700 deg. C for 1 h. Based on the results of X-ray photoelectron spectroscopy and photoluminescence spectra,more » the mechanisms of visible emission were discussed. - Research Highlights: {yields} ZnO nanorod array with good crystallography, low defects concentration and good optical property was obtained after annealed at 700 deg. C for 1 h. {yields} The transition from the conduction band to the O{sub i} level may be responsible for the yellow-green emission. {yields} The yellow emission may originate from the presence of Zn(OH){sub 2} on the surface or the band transition from conduction band to V{sub o}Zn{sub i} level. {yields} The transition from the Zn{sub i} level to the level should produce an orange emission or an orange-red emission.« less

The performance of DC restoration function for MODIS thermal emissive bands

NASA Astrophysics Data System (ADS)

Wang, Zhipeng; Xiong, Xiaoxiong Jack; Shrestha, Ashish

2017-09-01

The DC restore (DCR) process of MODIS instrument maintains the output of a detector at focal plane assembly (FPA) within the dynamic range of subsequent analog-to-digital converter, by adding a specific offset voltage to the output. The DCR offset value is adjusted per scan, based on the comparison of the detector response in digital number (DN) collected from the blackbody (BB) view with target DN saved as an on-board look-up table. In this work, the MODIS DCR mechanism is revisited, with the trends of DCR offset being provided for thermal emissive bands (TEB). Noticeable changes have been occasionally found which coincide with significant detector gain change due to various instrumental events such as safe-mode anomaly or FPA temperature fluctuation. In general, MODIS DCR functionality has been effective and the change of DCR offset has no impact to the quality of MODIS data. One exception is the Earth view (EV) data saturation of Aqua MODIS LWIR bands 33, 35 ad 36 during BB warm-up cool-down (WUCD) cycle which has been observed since 2008. The BB view of their detectors saturate when the BB temperature is above certain threshold so the DCR cannot work as designed. Therefore, the dark signal DN fluctuates with the cold FPA (CFPA) temperature and saturate for a few hours per WUCD cycle, which also saturate the EV data sector within the scan. The CFPA temperature fluctuation peaked in 2012 and has been reduced in recent years and the saturation phenomenon has been easing accordingly. This study demonstrates the importance of DCR to data generation.

A novel yellow-emitting SrAlSi4N7:Ce3+ phosphor for solid state lighting: Synthesis, electronic structure and photoluminescence properties

NASA Astrophysics Data System (ADS)

Ruan, Jian; Xie, Rong-Jun; Funahashi, Shiro; Tanaka, Yoshinori; Takeda, Takashi; Suehiro, Takayuki; Hirosaki, Naoto; Li, Yuan-Qiang

2013-12-01

Ce3+-doped and Ce3+/Li+-codoped SrAlSi4N7 phosphors were synthesized by gas pressure sintering of powder mixtures of Sr3N2, AlN, α-Si3N4, CeN and Li3N. The phase purity, electronic crystal structure, photoluminescence properties of SrAlSi4N7:Ce3+(Ce3+/Li+) were investigated in this work. The band structure calculated by the DMol3 code shows that SrAlSi4N7 has a direct band gap of 3.87 eV. The single crystal analysis of Ce3+-doped SrAlSi4N7 indicates a disordered Si/Al distribution and nitrogen vacnacy defects. SrAlSi4N7 was identified as a major phase of the fired powders, and Sr5Al5Si21N35O2 and AlN as minor phases. Both Ce3+ and Ce3+/Li+ doped SrAlSi4N7 phosphors can be efficiently excited by near-UV or blue light and show a broadband yellow emission peaking around 565 nm. A highest external quantum efficiency of 38.3% under the 450 nm excitation was observed for the Ce3+/Li+-doped SrAlSi4N7 (5 mol%). A white light LED lamp with color temperature of 6300 K and color rendering index of Ra=78 was achieved by combining Sr0.97Al1.03Si3.997N\\94\\maccounttest14=t0005_18193 7:Ce3+0.03 with a commercial blue InGaN chip. It indicates that SrAlSi4N7:Ce3+ is a promising yellow emitting down-conversion phosphor for white LEDs.

Near-infrared Spectroscopic Observations of Comet C/2013 R1 (Lovejoy) by WINERED: CN Red-system Band Emission

NASA Astrophysics Data System (ADS)

Shinnaka, Yoshiharu; Kawakita, Hideyo; Kondo, Sohei; Ikeda, Yuji; Kobayashi, Naoto; Hamano, Satoshi; Sameshima, Hiroaki; Fukue, Kei; Matsunaga, Noriyuki; Yasui, Chikako; Izumi, Natsuko; Mizumoto, Misaki; Otsubo, Shogo; Takenaka, Keiichi; Watase, Ayaka; Kawanishi, Takafumi; Nakanishi, Kenshi; Nakaoka, Tetsuya

2017-08-01

Although high-resolution spectra of the CN red-system band are considered useful in cometary sciences, e.g., in the study of isotopic ratios of carbon and nitrogen in cometary volatiles, there have been few reports to date due to the lack of high-resolution (R ≡ λ/Δλ > 20,000) spectrographs in the near-infrared region around ˜1 μm. Here, we present the high-resolution emission spectrum of the CN red-system band in comet C/2013 R1 (Lovejoy), acquired by the near-infrared high-resolution spectrograph WINERED mounted on the 1.3 m Araki telescope at the Koyama Astronomical Observatory, Kyoto, Japan. We applied our fluorescence excitation models for CN, based on modern spectroscopic studies, to the observed spectrum of comet C/2013 R1 (Lovejoy) to search for CN isotopologues (13C14N and 12C15N). We used a CN fluorescence excitation model involving both a “pure” fluorescence excitation model for the outer coma and a “fully collisional” fluorescence excitation model for the inner coma region. Our emission model could reproduce the observed 12C14N red-system band of comet C/2013 R1 (Lovejoy). The derived mixing ratio between the two excitation models was 0.94(+0.02/-0.03):0.06(+0.03/-0.02), corresponding to the radius of the collision-dominant region of ˜800-1600 km from the nucleus. No isotopologues were detected. The observed spectrum is consistent, within error, with previous estimates in comets of 12C/13C (˜90) and 14N/15N (˜150).

[Near ultraviolet absorption spectral properties of chromophoric dissolved organic matter in the north area of Yellow Sea].

PubMed

Wang, Lin; Zhao, Dong-Zhi; Yang, Jian-Hong; Chen, Yan-Long

2010-12-01

Chromophoric dissolved organic matter (CDOM) near ultraviolet absorption spectra contains CDOM molecular structure, composition and other important physical and chemical information. Based on the measured data of CDOM absorption coefficient in March 2009 in the north area of Yellow Sea, the present paper analyzed near ultraviolet absorption spectral properties of CDOM. The results showed that due to the impact of near-shore terrigenous input, the composition of CDOM is quite different in the north area of Yellow Sea, and this area is a typical case II water; fitted slope with specific range of spectral band and absorption coefficient at specific band can indicate the relative size of CDOM molecular weight, correlation between spectral slope of the Sg,275-300), Sg,300-350, Sg,350-400 and Sg,250-275 and the relative size of CDOM molecular weight indicative parameter M increases in turn and the highest is up to 0.95. Correlation between a(g)(lambda) and M value increases gradually with the increase in wavelength, and the highest is up to 0.92 at 400 nm; being correlated or not between spectral slope and absorption coefficient is decided by the fitting-band wavelength range for the spectra slope and the wavelength for absorption coefficient. Correlation between Sg,275-300 and a(g)(400) is the largest, up to 0.87.

Single photon infrared emission spectroscopy: a study of IR emission from UV laser excited PAHs between 3 and 15 micrometers

NASA Technical Reports Server (NTRS)

Cook, D. J.; Schlemmer, S.; Balucani, N.; Wagner, D. R.; Harrison, J. A.; Steiner, B.; Saykally, R. J.

1998-01-01

Single-photon infrared emission spectroscopy (SPIRES) has been used to measure emission spectra from polycyclic aromatic hydrocarbons (PAHs). A supersonic free-jet expansion has been used to provide emission spectra of rotationally cold and vibrationally excited naphthalene and benzene. Under these conditions, the observed width of the 3.3-micrometers (C-H stretch) band resembles the bandwidths observed in experiments in which emission is observed from naphthalene with higher rotational energy. To obtain complete coverage of IR wavelengths relevant to the unidentified infrared bands (UIRs), UV laser-induced desorption was used to generate gas-phase highly excited PAHs. Lorentzian band shapes were convoluted with the monochromator-slit function in order to determine the widths of PAH emission bands under astrophysically relevant conditions. Bandwidths were also extracted from bands consisting of multiple normal modes blended together. These parameters are grouped according to the functional groups mostly involved in the vibration, and mean bandwidths are obtained. These bandwidths are larger than the widths of the corresponding UIR bands. However, when the comparison is limited to the largest PAHs studied, the bandwidths are slightly smaller than the corresponding UIR bands. These parameters can be used to model emission spectra from PAH cations and cations of larger PAHs, which are better candidate carriers of the UIRs.

Near-infrared Thermal Emission from TrES-3b: A Ks-band Detection and an H-band Upper Limit on the Depth of the Secondary Eclipse

NASA Astrophysics Data System (ADS)

Croll, Bryce; Jayawardhana, Ray; Fortney, Jonathan J.; Lafrenière, David; Albert, Loic

2010-08-01

We present H- and Ks-band photometry bracketing the secondary eclipse of the hot Jupiter TrES-3b using the Wide-field Infrared Camera on the Canada-France-Hawaii Telescope. We detect the secondary eclipse of TrES-3b with a depth of 0.133+0.018 -0.016% in the Ks band (8σ)—a result that is in sharp contrast to the eclipse depth reported by de Mooij & Snellen. We do not detect its thermal emission in the H band, but place a 3σ limit of 0.051% on the depth of the secondary eclipse in this band. A secondary eclipse of this depth in Ks requires very efficient day-to-nightside redistribution of heat and nearly isotropic reradiation, a conclusion that is in agreement with longer wavelength, mid-infrared Spitzer observations. Our 3σ upper limit on the depth of our H-band secondary eclipse also argues for very efficient redistribution of heat and suggests that the atmospheric layer probed by these observations may be well homogenized. However, our H-band upper limit is so constraining that it suggests the possibility of a temperature inversion at depth, or an absorbing molecule, such as methane, that further depresses the emitted flux at this wavelength. The combination of our near-infrared measurements and those obtained with Spitzer suggests that TrES-3b displays a near-isothermal dayside atmospheric temperature structure, whose spectrum is well approximated by a blackbody. We emphasize that our strict H-band limit is in stark disagreement with the best-fit atmospheric model that results from longer wavelength observations only, thus highlighting the importance of near-infrared observations at multiple wavelengths, in addition to those returned by Spitzer in the mid-infrared, to facilitate a comprehensive understanding of the energy budgets of transiting exoplanets. Based on observations obtained with WIRCam, a joint project of CFHT, Taiwan, Korea, Canada, France, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of

Ultrafast dynamics of photoactive yellow protein via the photoexcitation and emission processes.

PubMed

Nakamura, Ryosuke; Hamada, Norio; Ichida, Hideki; Tokunaga, Fumio; Kanematsu, Yasuo

2007-01-01

Pump-dump fluorescence spectroscopy was performed for photoactive yellow protein (PYP) at room temperature. The effect of the dump pulse on the population of the potential energy surface of the electronic excited state was examined as depletion in the stationary fluorescence intensity. The dynamic behavior of the population in the electronic excited state was successfully probed in the various combinations of the pump-dump delay, the dump-pulse wavelength, the dump-pulse energy and the observation wavelength. The experimental results were compared with the results obtained by the femtosecond time-resolved fluorescence spectroscopy.

L Band Service Compatibility Part I: Optimum OOBE Compatibility

DOT National Transportation Integrated Search

2014-12-04

Discussion: -- Two Parts - Today we focus on optimum L Band ABC Out of Band Emission into GPS L1, OOBE. - Next ABC meeting will examine GPS-side mitigation of Adjacent Band Interference, ABI. -- Greater Compatibility: OOBE and ABI are distinct but pa...

New Kronig-Penney Equation Emphasizing the Band Edge Conditions

ERIC Educational Resources Information Center

Szmulowicz, Frank

2008-01-01

The Kronig-Penney problem is a textbook example for discussing band dispersions and band gap formation in periodic layered media. For example, in photonic crystals, the behaviour of bands next to the band edges is important for further discussions of such effects as inhibited light emission, slow light and negative index of refraction. However,…

Yellow fever: an update.

PubMed

Monath, T P

2001-08-01

Yellow fever, the original viral haemorrhagic fever, was one of the most feared lethal diseases before the development of an effective vaccine. Today the disease still affects as many as 200,000 persons annually in tropical regions of Africa and South America, and poses a significant hazard to unvaccinated travellers to these areas. Yellow fever is transmitted in a cycle involving monkeys and mosquitoes, but human beings can also serve as the viraemic host for mosquito infection. Recent increases in the density and distribution of the urban mosquito vector, Aedes aegypti, as well as the rise in air travel increase the risk of introduction and spread of yellow fever to North and Central America, the Caribbean and Asia. Here I review the clinical features of the disease, its pathogenesis and pathophysiology. The disease mechanisms are poorly understood and have not been the subject of modern clinical research. Since there is no specific treatment, and management of patients with the disease is extremely problematic, the emphasis is on preventative vaccination. As a zoonosis, yellow fever cannot be eradicated, but reduction of the human disease burden is achievable through routine childhood vaccination in endemic countries, with a low cost for the benefits obtained. The biological characteristics, safety, and efficacy of live attenuated, yellow fever 17D vaccine are reviewed. New applications of yellow fever 17D virus as a vector for foreign genes hold considerable promise as a means of developing new vaccines against other viruses, and possibly against cancers.

Calibration of VIIRS F1 Sensor Fire Detection Band Using lunar Observations

NASA Technical Reports Server (NTRS)

McIntire, Jeff; Efremova, Boryana; Xiong, Xiaoxiong

2012-01-01

Visible Infrared Imager Radiometer Suite (VIIRS) Fight 1 (Fl) sensor includes a fire detection band at roughly 4 microns. This spectral band has two gain states; fire detection occurs in the low gain state above approximately 345 K. The thermal bands normally utilize an on-board blackbody to provide on-orbit calibration. However, as the maximum temperature of this blackbody is 315 K, the low gain state of the 4 micron band cannot be calibrated in the same manner as the rest of the thermal bands. Regular observations of the moon provide an alternative calibration source. The lunar surface temperature has been recently mapped by the DIVINER sensor on the LRO platform. The periodic on-board high gain calibration along with the DIVINER surface temperatures was used to determine the emissivity and solar reflectance of the lunar surface at 4 microns; these factors and the lunar data are then used to fit the low gain calibration coefficients of the 4 micron band. Furthermore, the emissivity of the lunar surface is well known near 8.5 microns due to the Christiansen feature (an emissivity maximum associated with Si-O stretching vibrations) and the solar reflectance is negligible. Thus, the 8.5 micron band is used for relative calibration with the 4 micron band to de-trend any temporal variations. In addition, the remaining thermal bands are analyzed in a similar fashion, with both calculated emissivities and solar reflectances produced.

Narrow-band evoked oto-acoustic emission from ears with normal and pathologic conditions.

PubMed

Takeda, Taizo; Kakigi, Akinobu; Takebayashi, Shinji; Ohono, Satoshi; Nishioka, Rie; Nakatani, Hiroaki

2010-01-01

Evoked oto-acoustic emission (EOAE), in particular the slow component, is fragile with the inner ear lesions and is apt to disappear in impaired ears. This presence is thought to mean that inner ear is not badly damaged, and that the presence of EOAEs in early stage sudden deafness carries a good prognosis. Narrow-band EOAE analysis would open a potentially promising way to manage sensorineural deafness. The aim of present study was to evaluate the characteristics of EOAEs from pathologic ears by a narrow-band EOAE analysis, which allowed us to investigate amplitude, frequency content and latency of EOAEs simultaneously and also to easily detect weak echoes in cases with inner ear lesions. EOAEs were analyzed by investigating narrow-band frequency contents of EOAEs, filtered by a 100-Hz step of pass bandwidth in frequency regions from 1.0 to 2.0 kHz, and by 500 Hz of pass bandwidth in the frequency ranges of 0.5-1.0 and 2.0-5.0 kHz. EOAE testing was performed in 40 normal ears and 111 ears with pathologic disorders, including sudden deafness, Ménière's disease and surgically proven acoustic neurinomas. Spontaneous oto-acoustic emission was investigated in some cases. In acoustic neurinoma, especially computed tomography scan and magnetic resonance imaging tests were performed to assess the tumor size. (1) Narrow-band EOAE analysis revealed that EOAEs from normal ears were composed of two main echo trains and several sub-echoes. The main echo trains were divided into a fast component with a short latency of <10 ms and a slow component with a long latency of >10 ms. (2) EOAEs could often be detected from ears with moderate to severe hearing loss >45 dB HL in early stage sudden deafness. The prognosis of sudden deafness was good in cases where both a fast component and slow component were detected in the acute stage within 2 weeks after the deafness onset, and was pessimistic, when either or both of them failed to recover. (3) In Ménière's disease, EOAE was found

Phylogeny of Yellow Fever Virus, Uganda, 2016.

PubMed

Hughes, Holly R; Kayiwa, John; Mossel, Eric C; Lutwama, Julius; Staples, J Erin; Lambert, Amy J

2018-08-17

In April 2016, a yellow fever outbreak was detected in Uganda. Removal of contaminating ribosomal RNA in a clinical sample improved the sensitivity of next-generation sequencing. Molecular analyses determined the Uganda yellow fever outbreak was distinct from the concurrent yellow fever outbreak in Angola, improving our understanding of yellow fever epidemiology.

Korea and the Yellow Sea

NASA Image and Video Library

2017-12-08

NASA image acquired September 24, 2012 City lights at night are a fairly reliable indicator of where people live. But this isn’t always the case, and the Korean Peninsula shows why. As of July 2012, South Korea’s population was estimated at roughly 49 million people, and North Korea’s population was estimated at about half that number. But where South Korea is gleaming with city lights, North Korea has hardly any lights at all—just a faint glimmer around Pyongyang. On September 24, 2012, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured this nighttime view of the Korean Peninsula. This imagery is from the VIIRS “day-night band,” which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe signals such as gas flares, auroras, wildfires, city lights, and reflected moonlight. The wide-area image shows the Korean Peninsula, parts of China and Japan, the Yellow Sea, and the Sea of Japan. The white inset box encloses an area showing ship lights in the Yellow Sea. Many of the ships form a line, as if assembling along a watery border. Following the 1953 armistice ending the Korean War, per-capita income in South Korea rose to about 17 times the per-capital income level of North Korea, according to the U.S. Central Intelligence Agency. Worldwide, South Korea ranks 12th in electricity production, and 10th in electricity consumption, per 2011 estimates. North Korea ranks 71st in electricity production, and 73rd in electricity consumption, per 2009 estimates. NASA Earth Observatory image by Jesse Allen and Robert Simmon, using VIIRS Day-Night Band data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Michon Scott. Instrument: Suomi NPP - VIIRS Credit: NASA Earth Observatory Click here to view all of the Earth at Night 2012

Scuss u-Band Emission as a Star-Formation-Rate Indicator

NASA Astrophysics Data System (ADS)

Zhou, Zhimin; Zhou, Xu; Wu, Hong; Fan, Xiao-Hui; Fan, Zhou; Jiang, Zhao-Ji; Jing, Yi-Peng; Li, Cheng; Lesser, Michael; Jiang, Lin-Hua; Ma, Jun; Nie, Jun-Dan; Shen, Shi-Yin; Wang, Jia-Li; Wu, Zhen-Yu; Zhang, Tian-Meng; Zou, Hu

2017-01-01

We present and analyze the possibility of using optical u-band luminosities to estimate star-formation rates (SFRs) of galaxies based on the data from the South Galactic Cap u band Sky Survey (SCUSS), which provides a deep u-band photometric survey covering about 5000 deg2 of the South Galactic Cap. Based on two samples of normal star-forming galaxies selected by the BPT diagram, we explore the correlations between u-band, Hα, and IR luminosities by combing SCUSS data with the Sloan Digital Sky Survey and Wide-field Infrared Survey Explorer (WISE). The attenuation-corrected u-band luminosities are tightly correlated with the Balmer decrement-corrected Hα luminosities with an rms scatter of ˜0.17 dex. The IR-corrected u luminosities are derived based on the correlations between the attenuation of u-band luminosities and WISE 12 (or 22) μm luminosities, and then calibrated with the Balmer-corrected Hα luminosities. The systematic residuals of these calibrations are tested against the physical properties over the ranges covered by our sample objects. We find that the best-fitting nonlinear relations are better than the linear ones and recommended to be applied in the measurement of SFRs. The systematic deviations mainly come from the pollution of old stellar population and the effect of dust extinction; therefore, a more detailed analysis is needed in future work.

Yellow-poplar seedfall pattern

Treesearch

LaMont G. Engle

1960-01-01

Knowing the pattern of seedfall can be helpful when trying to regenerate yellow-poplar. This is especially true if the stand contains only scattered yellow-poplar seed trees. Information obtained from seed collections in Indiana shows that most of the seed falls north and northeast of seed trees.

Near-infrared Spectroscopic Observations of Comet C/2013 R1 (Lovejoy) by WINERED: CN Red-system Band Emission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shinnaka, Yoshiharu; Yasui, Chikako; Izumi, Natsuko

Although high-resolution spectra of the CN red-system band are considered useful in cometary sciences, e.g., in the study of isotopic ratios of carbon and nitrogen in cometary volatiles, there have been few reports to date due to the lack of high-resolution ( R  ≡  λ /Δ λ  > 20,000) spectrographs in the near-infrared region around ∼1 μ m. Here, we present the high-resolution emission spectrum of the CN red-system band in comet C/2013 R1 (Lovejoy), acquired by the near-infrared high-resolution spectrograph WINERED mounted on the 1.3 m Araki telescope at the Koyama Astronomical Observatory, Kyoto, Japan. We applied our fluorescence excitation models for CN, based onmore » modern spectroscopic studies, to the observed spectrum of comet C/2013 R1 (Lovejoy) to search for CN isotopologues ({sup 13}C{sup 14}N and {sup 12}C{sup 15}N). We used a CN fluorescence excitation model involving both a “pure” fluorescence excitation model for the outer coma and a “fully collisional” fluorescence excitation model for the inner coma region. Our emission model could reproduce the observed {sup 12}C{sup 14}N red-system band of comet C/2013 R1 (Lovejoy). The derived mixing ratio between the two excitation models was 0.94(+0.02/−0.03):0.06(+0.03/−0.02), corresponding to the radius of the collision-dominant region of ∼800–1600 km from the nucleus. No isotopologues were detected. The observed spectrum is consistent, within error, with previous estimates in comets of {sup 12}C/{sup 13}C (∼90) and {sup 14}N/{sup 15}N (∼150).« less

Long-lasting X-ray emission from type IIb supernova 2011dh and mass-loss history of the yellow supergiant progenitor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maeda, Keiichi; Katsuda, Satoru; Bamba, Aya

2014-04-20

Type IIb supernova (SN) 2011dh, with conclusive detection of an unprecedented yellow supergiant (YSG) progenitor, provides an excellent opportunity to deepen our understanding on the massive star evolution in the final centuries toward the SN explosion. In this paper, we report on detection and analyses of thermal X-ray emission from SN IIb 2011dh at ∼500 days after the explosion on Chandra archival data, providing a solidly derived mass-loss rate of a YSG progenitor for the first time. We find that the circumstellar media should be dense, more than that expected from a Wolf-Rayet (W-R) star by one order of magnitude.more » The emission is powered by a reverse shock penetrating into an outer envelope, fully consistent with the YSG progenitor but not with a W-R progenitor. The density distribution at the outermost ejecta is much steeper than that expected from a compact W-R star, and this finding must be taken into account in modeling the early UV/optical emission from SNe IIb. The derived mass-loss rate is ∼3 × 10{sup –6} M {sub ☉} yr{sup –1} for the mass-loss velocity of ∼20 km s{sup –1} in the final ∼1300 yr before the explosion. The derived mass-loss properties are largely consistent with the standard wind mass-loss expected for a giant star. This is not sufficient to be a main driver to expel nearly all the hydrogen envelope. Therefore, the binary interaction, with a huge mass transfer having taken place at ≳ 1300 yr before the explosion, is a likely scenario to produce the YSG progenitor.« less

21 CFR 137.215 - Yellow corn flour.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Yellow corn flour. 137.215 Section 137.215 Food... Flours and Related Products § 137.215 Yellow corn flour. Yellow corn flour conforms to the definition and standard of identity prescribed by § 137.211 for white corn flour except that cleaned yellow corn is used...

21 CFR 137.275 - Yellow corn meal.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Yellow corn meal. 137.275 Section 137.275 Food and... Related Products § 137.275 Yellow corn meal. Yellow corn meal conforms to the definition and standard of identity prescribed by § 137.250 for white corn meal except that cleaned yellow corn is used instead of...

21 CFR 137.215 - Yellow corn flour.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Yellow corn flour. 137.215 Section 137.215 Food... Flours and Related Products § 137.215 Yellow corn flour. Yellow corn flour conforms to the definition and standard of identity prescribed by § 137.211 for white corn flour except that cleaned yellow corn is used...

21 CFR 137.275 - Yellow corn meal.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Yellow corn meal. 137.275 Section 137.275 Food and... Related Products § 137.275 Yellow corn meal. Yellow corn meal conforms to the definition and standard of identity prescribed by § 137.250 for white corn meal except that cleaned yellow corn is used instead of...

The circumstellar dust envelopes of red giant stars. I - M giant stars with the 10-micron silicate emission band

NASA Technical Reports Server (NTRS)

Hashimoto, O.; Nakada, Y.; Onaka, T.; Kamijo, F.; Tanabe, T.

1990-01-01

Spherical dust envelope models of red giant stars are constructed by solving the radiative transfer equations of the generalized two-stream Eddington approximation. The IRAS observations of M giant stars which show the 10-micron silicate emission band in IRAS LRS spectra are explained by the models with the dirty silicate grains with K proportional to lambda exp -1.5 for lambda greather than 28 microns. Under the assumption of steady mass flow in the envelope, this model analysis gives the following conclusions: (1) the strength of the silicate emission peak at 10 microns is a good indicator of the mass loss rate of the star, (2) no stars with the 10-microns silicate emission feature are observed in the range of mass loss rate smaller than 7 x 10 to the -8th solar mass/yr, and (3) the characteristic time of the mass loss process of M stars does not exceed a few 10,000 years.

SCUSS u- BAND EMISSION AS A STAR-FORMATION-RATE INDICATOR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Zhimin; Zhou, Xu; Wu, Hong

2017-01-20

We present and analyze the possibility of using optical u- band luminosities to estimate star-formation rates (SFRs) of galaxies based on the data from the South Galactic Cap u band Sky Survey (SCUSS), which provides a deep u -band photometric survey covering about 5000 deg{sup 2} of the South Galactic Cap. Based on two samples of normal star-forming galaxies selected by the BPT diagram, we explore the correlations between u -band, H α , and IR luminosities by combing SCUSS data with the Sloan Digital Sky Survey and Wide-field Infrared Survey Explorer ( WISE ). The attenuation-corrected u -band luminositiesmore » are tightly correlated with the Balmer decrement-corrected H α luminosities with an rms scatter of ∼0.17 dex. The IR-corrected u luminosities are derived based on the correlations between the attenuation of u- band luminosities and WISE 12 (or 22) μ m luminosities, and then calibrated with the Balmer-corrected H α luminosities. The systematic residuals of these calibrations are tested against the physical properties over the ranges covered by our sample objects. We find that the best-fitting nonlinear relations are better than the linear ones and recommended to be applied in the measurement of SFRs. The systematic deviations mainly come from the pollution of old stellar population and the effect of dust extinction; therefore, a more detailed analysis is needed in future work.« less

Impact of the wetting layer thickness on the emission wavelength of direct band gap GeSn/Ge quantum dots

NASA Astrophysics Data System (ADS)

Ilahi, Bouraoui; Al-Saigh, Reem; Salem, Bassem

2017-07-01

The effects of the wetting layer thickness (t WL) on the electronic properties of direct band gap type-I strained dome shaped Ge(1-x)Sn x quantum dot (QD) embedded in Ge matrix is numerically studied. The emission wavelength and the energy difference between S and P electron levels have been evaluated as a function of t WL for different QD size and composition with constant height to diameter ratio. The emission wavelength is found to be red shifted by increasing the wetting layer thickness, with smaller size QD being more sensitive to the variation of t WL. Furthermore, the minimum Sn composition required to fit the directness criteria is found to reduce by increasing the wetting layer thickness.

A new distinctively banded-species of Panaqolus (Siluriformes: Loricariidae) from the western Amazon Basin in Peru.

PubMed

Lujan, Nathan K; Steele, Sarah; Velasquez, Miquel

2013-01-01

Panaqolus albivermis is described as a new species based on four specimens from the San Alejandro River, a tributary of the upper Ucayali River in central Peru. Panaqolus albivermis is diagnosed from all other Panaqolus except P. maccus by having head, body, and fins with widely separated small white to yellow spots, vermiculations, and/or thin oblique bands on a black base (vs. exclusively small white to yellow spots on a black base in P. alboinaculatus, generally broad oblique bands of alternating light to dark brown in P. changae, P. gnomus, P purusiensis, and a uniformly dark gray to black body color in P. dentex, P. koko, and P. nocturnus); P. albivernis can be diagnosed from P. maccus by having a black base color (vs. brown), by having parallel dentary tooth cups (vs. acute intermandibular tooth cup angle), and by having a larger known adult body size (95.8 mm SL vs. 84.8).

Sensible Ozone on Mars based on 2-D Maps of O 2(a 1△ g) Emission for L s=102° Comparison of (0,0) and (1,1) Bands

NASA Astrophysics Data System (ADS)

Novak, Robert E.; Mumma, Michael J.; Villanueva, Geronimo Luis

2016-10-01

We report 2-D maps of the O2(a1△g) emission rate (a tracer for high-altitude ozone) taken during early northern summer (Ls=102° on 30 January 2016) using CSHELL at NASA's IRTF. The entrance slit of the spectrometer was positioned N-S on Mars and stepped E-W at 0.5 arc-sec increments. Spectral extracts were taken at 0.6 arc-sec intervals along the slit. We also took data to compare the emission rates of the O2(a1△g) (1-1) band (1.28 μm) to the (0-0) band (1.27 μm) with the entrance slit centered at the sub-Earth point. A model consisting of the solar continuum with Fraunhofer lines, two-way transmission through Mars' atmosphere, and a one-way transmission through the Earth's atmosphere was used to isolate and analyze individual spectral emission lines from Mars. Boltzmann analysis of these lines yielded a rotational temperature (~165 K) that was used to determine the total emission rates for the a-X system from the measured line intensities. The line-of-sight emission rates were converted to vertical emission rates and O2(a1△g) column densities after geometric correction. The sensible O3 column implied by these data is compared with maps of total O3 in Mars standard atmosphere models.The 2-D map shows increased emission in the southern hemisphere when compared to previously reported results taken at earlier seasonal points (Ls=72° on 3 April 2010 and Ls=88° on 10 February 2014). Emission results of the O2(a1△g) (0-0) band (Local Time ~ 14:30) will be compared with MARCI results (LT ~ 15:00, Clancy et al., Icarus 266 (2016) 112-113). We searched for the (1-1) band in two adjacent wavelength ranges; (0-0) emissions were detected at these settings, but no (1-1) emissions were noticed above the noise level. An upper limit will be presented, and implications discussed.This work was partially funded by grants from NASA's Mars Fundamental Research Program (11-MFRP11-0066) and the NSF-RUI Program (AST-805540). The NASA Astrobiology Institute supported this work

Relative spectral response corrected calibration inter-comparison of S-NPP VIIRS and Aqua MODIS thermal emissive bands

NASA Astrophysics Data System (ADS)

Efremova, Boryana; Wu, Aisheng; Xiong, Xiaoxiong

2014-09-01

The S-NPP Visible Infrared Imaging Radiometer Suite (VIIRS) instrument is built with strong heritage from EOS MODIS, and has very similar thermal emissive bands (TEB) calibration algorithm and on-board calibrating source - a V-grooved blackbody. The calibration of the two instruments can be assessed by comparing the brightness temperatures retrieved from VIIRS and Aqua MODIS simultaneous nadir observations (SNO) from their spectrally matched TEB. However, even though the VIIRS and MODIS bands are similar there are still relative spectral response (RSR) differences and thus some differences in the retrieved brightness temperatures are expected. The differences depend on both the type and the temperature of the observed scene, and contribute to the bias and the scatter of the comparison. In this paper we use S-NPP Cross-track Infrared Sounder (CrIS) data taken simultaneously with the VIIRS data to derive a correction for the slightly different spectral coverage of VIIRS and MODIS TEB bands. An attempt to correct for RSR differences is also made using MODTRAN models, computed with physical parameters appropriate for each scene, and compared to the value derived from actual CrIS spectra. After applying the CrIS-based correction for RSR differences we see an excellent agreement between the VIIRS and Aqua MODIS measurements in the studied band pairs M13-B23, M15-B31, and M16- B32. The agreement is better than the VIIRS uncertainty at cold scenes, and improves with increasing scene temperature up to about 290K.

Auroral nitric oxide concentration and infrared emission

NASA Astrophysics Data System (ADS)

Reidy, W. P.; Degges, T. C.; Hurd, A. G.; Stair, A. T., Jr.; Ulwick, J. C.

1982-05-01

Rocket-borne measurements of infrared auroral emission by nitric oxide are analyzed. Four rocket flights provided opportunities to measure 5.3- and 2.7-micron NO emission by means of infrared fixed band radiometers and CVF spectrometers, narrow band photometers, and incident energy spectra on various occasions. Analysis of infrared emission profiles and electron flux data indicates the NO density to be significantly enhanced with respect to midlatitude values. NO emission in the fundamental 5.3-micron band is attributed to resonance excitation by warm earth radiation, collisional excitation primarily by O atoms and chemiluminescence from the reaction of N with O2; with an energy efficiency of 0.015. The overtone band emission at 2.7 microns is accounted for by chemiluminescence produced with an energy efficiency of 0.0054. Total photon yield for the chemiluminescence reaction is estimated to range from 1.2 to 2.4 vibrational quanta per NO molecule.

Paintable band-edge liquid crystal lasers.

PubMed

Gardiner, Damian J; Morris, Stephen M; Hands, Philip J W; Mowatt, Carrie; Rutledge, Rupert; Wilkinson, Timothy D; Coles, Harry J

2011-01-31

In this paper we demonstrate photonic band-edge laser emission from emulsion-based polymer dispersed liquid crystals. The lasing medium consists of dye-doped chiral nematic droplets dispersed within a polymer matrix that spontaneously align as the film dries. Such lasers can be easily formed on single substrates with no alignment layers. The system combines the self-organizing periodic structure of chiral nematic liquid crystals with the simplicity of the emulsion procedure so as to produce a material that retains the emission characteristics of band-edge lasers yet can be readily coated. Sequential and stacked layers demonstrate the possibility of achieving simultaneous multi-wavelength laser output from glass, metallic, and flexible substrates.

Cytotoxicity of yellow sand in lung epithelial cells.

PubMed

Kim, Y H; Kim, K S; Kwak, N J; Lee, K H; Kweon, S A; Lim, Y

2003-02-01

The present study was carried out to observe the cytotoxicity of yellow sand in comparison with silica and titanium dioxide in a rat alveolar type II cell line (RLE-6TN). Yellow sand (China Loess) was obtained from the loess layer in the Gunsu Province of China. The mean particle diameter of yellow sand was about 0.003 +/- 0.001 mm. Major elements of yellow sand were Si(27.7 +/- 0.6%), Al(6.01 +/- 0.17%), and Ca(5.83 +/- 0.23%) in that order. Silica and yellow sand significantly decreased cell viability and increased [Ca2+]i. All three particles increased the generation of H2O2. TiO2 did not change Fenton activity, while silica induced a slight increase of Fenton activity. In contrast, yellow sand induced a significant increase of Fenton activity. Silica, yellow sand and TiO2 induced significant nitrite formations in RLE-6TN cells. Silica showed the highest increase in nitrite formation, while yellow sand induced the least formation of nitrite. Silica and yellow sand increased the release of TNF-a. Based on these results, we suggest that yellow sand can induce cytotoxicity in RLE-6TN cells and reactive oxygen species, Fenton activity and reactive nitrogen species might be involved in this toxicity.

Yellow phosphorus-induced Brugada phenocopy.

PubMed

Dharanipradab, Mayakrishnan; Viswanathan, Stalin; Kumar, Gokula Raman; Krishnamurthy, Vijayalatchumy; Stanley, Daphene Divya

Metallic phosphides (of aluminum and phosphide) and yellow phosphorus are commonly used rodenticide compounds in developing countries. Toxicity of yellow phosphorus mostly pertains to the liver, kidney, heart, pancreas and the brain. Cardiotoxicity with associated Brugada ECG pattern has been reported only in poisoning with metallic phosphides. Brugada phenocopy and hepatic dysfunction were observed in a 29-year-old male following yellow phosphorus consumption. He had both type 1 (day1) and type 2 (day2) Brugada patterns in the electrocardiogram, which resolved spontaneously by the third day without hemodynamic compromise. Toxins such as aluminum and zinc phosphide have been reported to induce Brugada ECG patterns due to the generation of phosphine. We report the first case of yellow phosphorus-related Brugada phenocopy, without hemodynamic compromise or malignant arrhythmia. Copyright © 2017 Elsevier Inc. All rights reserved.

Perinatal Yellow Fever: A Case Report.

PubMed

Diniz, Lilian Martins Oliveira; Romanelli, Roberta Maia Castro; de Carvalho, Andréa Lucchesi; Teixeira, Daniela Caldas; de Carvalho, Luis Fernando Andrade; Cury, Verônica Ferreira; Filho, Marcelo Pereira Lima; Perígolo, Graciele; Heringer, Tiago Pires

2018-04-09

An outbreak of yellow fever in Brazil made it possible to assess different presentations of disease such as perinatal transmission. A pregnant woman was admitted to hospital with yellow fever symptoms. She was submitted to cesarean section and died due to fulminant hepatitis. On the 6th day the newborn developed liver failure and died 13 days later. Yellow fever PCR was positive for both.

An evaluation of yellow-flowering magnolias and magnolia rootstocks

USDA-ARS?s Scientific Manuscript database

Yellow-flowering magnolias were evaluated for flower color, bloom duration and growth rate in USDA Hardiness Zone 6b. Of the thirty selections evaluated, all were reported to have yellow blooms; however, tepal color ranged from light pink with some yellow coloration, to creamy yellow to dark yellow....

The GOES-R Advanced Baseline Imager: detector spectral response effects on thermal emissive band calibration

NASA Astrophysics Data System (ADS)

Pearlman, Aaron J.; Padula, Francis; Cao, Changyong; Wu, Xiangqian

2015-10-01

The Advanced Baseline Imager (ABI) will be aboard the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellite R-Series (GOES-R) to supply data needed for operational weather forecasts and long-term climate variability studies, which depend on high quality data. Unlike the heritage operational GOES systems that have two or four detectors per band, ABI has hundreds of detectors per channel requiring calibration coefficients for each one. This increase in number of detectors poses new challenges for next generation sensors as each detector has a unique spectral response function (SRF) even though only one averaged SRF per band is used operationally to calibrate each detector. This simplified processing increases computational efficiency. Using measured system-level SRF data from pre-launch testing, we have the opportunity to characterize the calibration impact using measured SRFs, both per detector and as an average of detector-level SRFs similar to the operational version. We calculated the spectral response impacts for the thermal emissive bands (TEB) theoretically, by simulating the ABI response viewing an ideal blackbody and practically, with the measured ABI response to an external reference blackbody from the pre-launch TEB calibration test. The impacts from the practical case match the theoretical results using an ideal blackbody. The observed brightness temperature trends show structure across the array with magnitudes as large as 0.1 K for and 12 (9.61 µm), and 0.25 K for band 14 (11.2 µm) for a 300 K blackbody. The trends in the raw ABI signal viewing the blackbody support the spectral response measurements results, since they show similar trends in bands 12 (9.61µm), and 14 (11.2 µm), meaning that the spectral effects dominate the response differences between detectors for these bands. We further validated these effects using the radiometric bias calculated between calibrations using the external blackbody and

InGaAs/InP quantum wires grown on silicon with adjustable emission wavelength at telecom bands

NASA Astrophysics Data System (ADS)

Han, Yu; Li, Qiang; Ng, Kar Wei; Zhu, Si; Lau, Kei May

2018-06-01

We report the growth of vertically stacked InGaAs/InP quantum wires on (001) Si substrates with adjustable room-temperature emission at telecom bands. Based on a self-limiting growth mode in selective area metal–organic chemical vapor deposition, crescent-shaped InGaAs quantum wires with variable dimensions are embedded within InP nano-ridges. With extensive transmission electron microscopy studies, the growth transition and morphology change from quantum wires to ridge quantum wells (QWs) have been revealed. As a result, we are able to decouple the quantum wires from ridge QWs and manipulate their dimensions by scaling the growth time. With minimized lateral dimension and their unique positioning, the InGaAs/InP quantum wires are more immune to dislocations and more efficient in radiative processes, as evidenced by their excellent optical quality at telecom-bands. These promising results thus highlight the potential of combining low-dimensional quantum wire structures with the aspect ratio trapping process for integrating III–V nano-light emitters on mainstream (001) Si substrates.

InGaAs/InP quantum wires grown on silicon with adjustable emission wavelength at telecom bands.

PubMed

Han, Yu; Li, Qiang; Ng, Kar Wei; Zhu, Si; Lau, Kei May

2018-06-01

We report the growth of vertically stacked InGaAs/InP quantum wires on (001) Si substrates with adjustable room-temperature emission at telecom bands. Based on a self-limiting growth mode in selective area metal-organic chemical vapor deposition, crescent-shaped InGaAs quantum wires with variable dimensions are embedded within InP nano-ridges. With extensive transmission electron microscopy studies, the growth transition and morphology change from quantum wires to ridge quantum wells (QWs) have been revealed. As a result, we are able to decouple the quantum wires from ridge QWs and manipulate their dimensions by scaling the growth time. With minimized lateral dimension and their unique positioning, the InGaAs/InP quantum wires are more immune to dislocations and more efficient in radiative processes, as evidenced by their excellent optical quality at telecom-bands. These promising results thus highlight the potential of combining low-dimensional quantum wire structures with the aspect ratio trapping process for integrating III-V nano-light emitters on mainstream (001) Si substrates.

21 CFR 137.285 - Degerminated yellow corn meal.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Degerminated yellow corn meal. 137.285 Section 137... Cereal Flours and Related Products § 137.285 Degerminated yellow corn meal. Degerminated yellow corn meal, degermed yellow corn meal, conforms to the definition and standard of identity prescribed by § 137.265 for...

21 CFR 137.285 - Degerminated yellow corn meal.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Degerminated yellow corn meal. 137.285 Section 137... Cereal Flours and Related Products § 137.285 Degerminated yellow corn meal. Degerminated yellow corn meal, degermed yellow corn meal, conforms to the definition and standard of identity prescribed by § 137.265 for...

A novel yellow-emitting SrAlSi{sub 4}N{sub 7}:Ce{sup 3+} phosphor for solid state lighting: Synthesis, electronic structure and photoluminescence properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruan, Jian; Laboratory of Glasses and Nanostructured Functional Materials, 122 Luoshi Road, Wuhan, Hubei 430070; Xie, Rong-Jun, E-mail: Xie.Rong-Jun@nims.go.jp

2013-12-15

Ce{sup 3+}-doped and Ce{sup 3+}/Li{sup +}-codoped SrAlSi{sub 4}N{sub 7} phosphors were synthesized by gas pressure sintering of powder mixtures of Sr{sub 3}N{sub 2}, AlN, α-Si{sub 3}N{sub 4}, CeN and Li{sub 3}N. The phase purity, electronic crystal structure, photoluminescence properties of SrAlSi{sub 4}N{sub 7}:Ce{sup 3+}(Ce{sup 3+}/Li{sup +}) were investigated in this work. The band structure calculated by the DMol{sup 3} code shows that SrAlSi{sub 4}N{sub 7} has a direct band gap of 3.87 eV. The single crystal analysis of Ce{sup 3+}-doped SrAlSi{sub 4}N{sub 7} indicates a disordered Si/Al distribution and nitrogen vacnacy defects. SrAlSi{sub 4}N{sub 7} was identified as a majormore » phase of the fired powders, and Sr{sub 5}Al{sub 5}Si{sub 21}N{sub 35}O{sub 2} and AlN as minor phases. Both Ce{sup 3+} and Ce{sup 3+}/Li{sup +} doped SrAlSi{sub 4}N{sub 7} phosphors can be efficiently excited by near-UV or blue light and show a broadband yellow emission peaking around 565 nm. A highest external quantum efficiency of 38.3% under the 450 nm excitation was observed for the Ce{sup 3+}/Li{sup +}-doped SrAlSi{sub 4}N{sub 7} (5 mol%). A white light LED lamp with color temperature of 6300 K and color rendering index of Ra=78 was achieved by combining Sr{sub 0.97}Al{sub 1.03}Si{sub 3.997}N/94/maccounttest14=t0005{sub 1}8193 {sub 7}:Ce{sup 3+}{sub 0.03} with a commercial blue InGaN chip. It indicates that SrAlSi{sub 4}N{sub 7}:Ce{sup 3+} is a promising yellow emitting down-conversion phosphor for white LEDs. - Graphical abstract: One-phosphor converted white light-emitting diode (LED) was fabricated by combining a blue LED chip and a yellow-emitting SrAlSi4N7:Ce{sup 3+} phosphor (see inset), which has the color rendering index of 78 and color temperature of 6300 K. - Highlights: • We reported a new yellow nitride phosphor suitable for solid state lighting. • We solved the crystal structure and evidenced a disordered Si/Al distribution. • We fabricated a high color

LANDSAT 4 band 6 data evaluation

NASA Technical Reports Server (NTRS)

1984-01-01

A series of images of a portion of a TM frame of Lake Ontario are presented. The top left frame is the TM Band 6 image, the top right image is a conventional contrast stretched image. The bottom left image is a Band 5 to Band 3 ratio image. This image is used to generate a primitive land cover classificaton. Each land cover (Water, Urban, Forest, Agriculture) is assigned a Band 6 emissivity value. The ratio image is then combined with the Band 6 image and atmospheric propagation data to generate the bottom right image. This image represents a display of data whose digital count can be directly related to estimated surface temperature. The resolution appears higher because the process cell is the size of the TM shortwave pixels.

Extended infrared emission around IRAS 21282 + 5050

NASA Technical Reports Server (NTRS)

Bregman, Jesse D.; Booth, John; Gilmore, D. K.; Kay, Laura; Rank, David

1992-01-01

Multiaperture 3-4-micron spectra along with K- and L-band images of the compact planetary nebula IRAS 21282 + 5050 show a 5 arcsec - 20 arcsec diameter nebula with structure similar to many other planetary nebulae. The spectral observations and the L-band image show evidence for extended PAH emission out to a radius of 20 arcsec, while the K-band image shows a 5 arcsec diameter nebula. An observed linear increase of integrated brightness with aperture size at L band implies a 1/r exp 2 volume emissivity for a spherically symmetric model. The spectral similarity of the emission in the small and large apertures suggests fluorescent emission by the PAHs. If the observed emission is from PAHs which formed during the planetary nebulae stage of IRAs 21282 + 5050, then PAHs have been forming for not less than 3000 yr. If the PAH emission is from material produced during the earlier red giant phase, then the formation time frame was much longer. The morphological and spectral similarity of IRAS 21282 + 5050 to many other planetary nebulae suggests that this phenomenon may be widespread, and that planetary nebulae may be a significant source of interstellar PAHs.

Study on the structural, optical, and electrical properties of the yellow light-emitting diode grown on free-standing (0001) GaN substrate

NASA Astrophysics Data System (ADS)

Deng, Gaoqiang; Zhang, Yuantao; Yu, Ye; Yan, Long; Li, Pengchong; Han, Xu; Chen, Liang; Zhao, Degang; Du, Guotong

2018-04-01

In this paper, GaN-based yellow light-emitting diodes (LEDs) were homoepitaxially grown on free-standing (0001) GaN substrates by metal-organic chemical vapor deposition. X-ray diffraction (XRD), photoluminescence (PL), and electroluminescence (EL) measurements were conducted to investigate the structural, optical, and electrical properties of the yellow LED. The XRD measurement results showed that the InGaN/GaN multiple quantum wells (MQWs) in the LED structure have good periodicity because the distinct MQWs related higher order satellite peaks can be clearly observed from the profile of 2θ-ω XRD scan. The low temperature (10 K) and room temperature PL measurement results yield an internal quantum efficiency of 16% for the yellow LED. The EL spectra of the yellow LED present well Gaussian distribution with relatively low linewidth (47-55 nm), indicating the homogeneous In-content in the InGaN quantum well layers in the yellow LED structure. It is believed that this work will aid in the future development of GaN on GaN LEDs with long emission wavelength.

17DD yellow fever vaccine

PubMed Central

Martins, Reinaldo M.; Maia, Maria de Lourdes S.; Farias, Roberto Henrique G.; Camacho, Luiz Antonio B.; Freire, Marcos S.; Galler, Ricardo; Yamamura, Anna Maya Yoshida; Almeida, Luiz Fernando C.; Lima, Sheila Maria B.; Nogueira, Rita Maria R.; Sá, Gloria Regina S.; Hokama, Darcy A.; de Carvalho, Ricardo; Freire, Ricardo Aguiar V.; Filho, Edson Pereira; Leal, Maria da Luz Fernandes; Homma, Akira

2013-01-01

Objective: To verify if the Bio-Manguinhos 17DD yellow fever vaccine (17DD-YFV) used in lower doses is as immunogenic and safe as the current formulation. Results: Doses from 27,476 IU to 587 IU induced similar seroconversion rates and neutralizing antibodies geometric mean titers (GMTs). Immunity of those who seroconverted to YF was maintained for 10 mo. Reactogenicity was low for all groups. Methods: Young and healthy adult males (n = 900) were recruited and randomized into 6 groups, to receive de-escalating doses of 17DD-YFV, from 27,476 IU to 31 IU. Blood samples were collected before vaccination (for neutralization tests to yellow fever, serology for dengue and clinical chemistry), 3 to 7 d after vaccination (for viremia and clinical chemistry) and 30 d after vaccination (for new yellow fever serology and clinical chemistry). Adverse events diaries were filled out by volunteers during 10 d after vaccination. Volunteers were retested for yellow fever and dengue antibodies 10 mo later. Seropositivity for dengue was found in 87.6% of volunteers before vaccination, but this had no significant influence on conclusions. Conclusion: In young healthy adults Bio-Manguinhos/Fiocruz yellow fever vaccine can be used in much lower doses than usual. International Register ISRCTN 38082350. PMID:23364472

Nd3+/Yb3+ cascade-sensitized single-band red upconversion emission in active-core/active-shell nanocrystals.

PubMed

Ding, M Y; Hou, J J; Yuan, Y J; Bai, W F; Lu, C H; Xi, J H; Ji, Z G; Chen, D Q

2018-08-24

Lanthanide-doped upconversion nanomaterials (UCNMs) have promoted extensive interest for its biological research and biomedical applications, benefiting from low autofluorescence background, deep light penetration depth, and minimal photo-damage to biological tissues. However, owing to the 980 nm laser-induced overheating issue and the attenuation effect associated with conventional multi-peak emissions, the usage of UCNMs as fluorescent bioprobes is still limited. To address these issues, an effective strategy has been proposed to tune both the excitation and emission peaks of UCNMs into the first biological window (650 ∼ 900 nm), where the light absorption by water and hemoglobin in biological tissues is minimal. Based on the Nd 3+ /Yb 3+ cascade-sensitized upconversion process and efficient exchange-energy transfer between Mn 2+ and Er 3+ in conjunction with the active-core@active-shell nanostructured design, we have developed a new class of upconversion nanoparticles (UCNPs) that exhibit strong single-band red emission upon excitation of an 808 nm near-infrared laser. Hopefully, the well-designed KMnF 3 :Yb/Er/Nd@ KMnF 3 :Yb/Nd core-shell nanocrystals will be considered a promising alternative to conventionally used UCNPs for biolabeling applications without the concern of the overheating issue and the attenuation constraints.

47 CFR 15.217 - Operation in the band 160-190 kHz.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 1 2012-10-01 2012-10-01 false Operation in the band 160-190 kHz. 15.217... Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.217 Operation in the band 160-190 k... lead (if used) shall not exceed 15 meters. (c) All emissions below 160 kHz or above 190 kHz shall be...

47 CFR 15.217 - Operation in the band 160-190 kHz.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 1 2011-10-01 2011-10-01 false Operation in the band 160-190 kHz. 15.217... Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.217 Operation in the band 160-190 k... lead (if used) shall not exceed 15 meters. (c) All emissions below 160 kHz or above 190 kHz shall be...

47 CFR 15.217 - Operation in the band 160-190 kHz.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 1 2013-10-01 2013-10-01 false Operation in the band 160-190 kHz. 15.217... Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.217 Operation in the band 160-190 k... lead (if used) shall not exceed 15 meters. (c) All emissions below 160 kHz or above 190 kHz shall be...

47 CFR 15.217 - Operation in the band 160-190 kHz.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 1 2014-10-01 2014-10-01 false Operation in the band 160-190 kHz. 15.217... Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.217 Operation in the band 160-190 k... lead (if used) shall not exceed 15 meters. (c) All emissions below 160 kHz or above 190 kHz shall be...

47 CFR 15.217 - Operation in the band 160-190 kHz.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation in the band 160-190 kHz. 15.217... Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.217 Operation in the band 160-190 k... lead (if used) shall not exceed 15 meters. (c) All emissions below 160 kHz or above 190 kHz shall be...

Efficient Incorporation of Mg in Solution Grown GaN Crystals

DTIC Science & Technology

2013-10-11

stronger contribution from the yellow/green defect band near 2.35 eV and smaller con- tributions from the 3.25 and 3:4 eV bands. The 3:4 eV emission...and N. Magna: Phys. Status Solidi B 102 (1980) 475. 16) J. Lee, E. S. Koteles, M. O. Vassell, and J. P. Salerno: J. Lumin . 34 (1985) 63. 17) B

Tunable Narrow Band Emissions from Dye-Sensitized Core/Shell/Shell Nanocrystals in the Second Near-Infrared Biological Window

PubMed Central

Shao, Wei; Chen, Guanying; Kuzmin, Andrey; Kutscher, Hilliard L.; Pliss, Artem; Ohulchanskyy, Tymish Y.; Prasad, Paras N.

2017-01-01

We introduce a hybrid organic–inorganic system consisting of epitaxial NaYF4:Yb3+/X3+@NaYbF4@NaYF4:Nd3+ (X = null, Er, Ho, Tm, or Pr) core/shell/shell (CSS) nanocrystal with organic dye, indocyanine green (ICG) on the nanocrystal surface. This system is able to produce a set of narrow band emissions with a large Stokes-shift (>200 nm) in the second biological window of optical transparency (NIR-II, 1000–1700 nm), by directional energy transfer from light-harvesting surface ICG, via lanthanide ions in the shells, to the emitter X3+ in the core. Surface ICG not only increases the NIR-II emission intensity of inorganic CSS nanocrystals by ~4-fold but also provides a broadly excitable spectral range (700–860 nm) that facilitates their use in bioapplications. We show that the NIR-II emission from ICG-sensitized Er3+-doped CSS nanocrystals allows clear observation of a sharp image through 9 mm thick chicken breast tissue, and emission signal detection through 22 mm thick tissue yielding a better imaging profile than from typically used Yb/Tm-codoped upconverting nanocrystals imaged in the NIR-I region (700–950 nm). Our result on in vivo imaging suggests that these ICG-sensitized CSS nanocrystals are suitable for deep optical imaging in the NIR-II region. PMID:27935695

Yellow-Poplar Site Index Curves

Treesearch

Donald E. Beck

1962-01-01

Yellow-poplar (Liriodendron tulipifera L.) occurs naturally throughout the eastern and central United States from southern New England west to Michigan and south to Florida and Louisiana. Because of its wide occurrence, yellow-poplar grows under a variety of climatic, edaphic, and biotic conditions. Combinations of these different environmental...

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

NASA Astrophysics Data System (ADS)

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

2012-12-01

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.

38 CFR 21.9700 - Yellow Ribbon Program.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 2 2011-07-01 2011-07-01 false Yellow Ribbon Program. 21... Ribbon Program. (a) Establishment. The “Yellow Ribbon G.I. Education Enhancement Program”, known as the “Yellow Ribbon Program,” permits an institution of higher learning (IHL), at the IHL's option, to enter...

38 CFR 21.9700 - Yellow Ribbon Program.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 2 2013-07-01 2013-07-01 false Yellow Ribbon Program. 21... Ribbon Program. (a) Establishment. The “Yellow Ribbon G.I. Education Enhancement Program”, known as the “Yellow Ribbon Program,” permits an institution of higher learning (IHL), at the IHL's option, to enter...

38 CFR 21.9700 - Yellow Ribbon Program.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Yellow Ribbon Program. 21... Ribbon Program. (a) Establishment. The “Yellow Ribbon G.I. Education Enhancement Program”, known as the “Yellow Ribbon Program,” permits an institution of higher learning (IHL), at the IHL's option, to enter...

38 CFR 21.9700 - Yellow Ribbon Program.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 2 2014-07-01 2014-07-01 false Yellow Ribbon Program. 21... Ribbon Program. (a) Establishment. The “Yellow Ribbon G.I. Education Enhancement Program”, known as the “Yellow Ribbon Program,” permits an institution of higher learning (IHL), at the IHL's option, to enter...

38 CFR 21.9700 - Yellow Ribbon Program.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 38 Pensions, Bonuses, and Veterans' Relief 2 2012-07-01 2012-07-01 false Yellow Ribbon Program. 21... Ribbon Program. (a) Establishment. The “Yellow Ribbon G.I. Education Enhancement Program”, known as the “Yellow Ribbon Program,” permits an institution of higher learning (IHL), at the IHL's option, to enter...

Fatal Yellow Fever in Travelers to Brazil, 2018.

PubMed

Hamer, Davidson H; Angelo, Kristina; Caumes, Eric; van Genderen, Perry J J; Florescu, Simin A; Popescu, Corneliu P; Perret, Cecilia; McBride, Angela; Checkley, Anna; Ryan, Jenny; Cetron, Martin; Schlagenhauf, Patricia

2018-03-23

Yellow fever virus is a mosquito-borne flavivirus that causes yellow fever, an acute infectious disease that occurs in South America and sub-Saharan Africa. Most patients with yellow fever are asymptomatic, but among the 15% who develop severe illness, the case fatality rate is 20%-60%. Effective live-attenuated virus vaccines are available that protect against yellow fever (1). An outbreak of yellow fever began in Brazil in December 2016; since July 2017, cases in both humans and nonhuman primates have been reported from the states of São Paulo, Minas Gerais, and Rio de Janeiro, including cases occurring near large urban centers in these states (2). On January 16, 2018, the World Health Organization updated yellow fever vaccination recommendations for Brazil to include all persons traveling to or living in Espírito Santo, São Paulo, and Rio de Janeiro states, and certain cities in Bahia state, in addition to areas where vaccination had been recommended before the recent outbreak (3). Since January 2018, 10 travel-related cases of yellow fever, including four deaths, have been reported in international travelers returning from Brazil. None of the 10 travelers had received yellow fever vaccination.

Dietary calcein marking of brook trout, Atlantic salmon, yellow perch, and coho salmon scales

USGS Publications Warehouse

Honeyfield, D.C.; Ostrowski, C.S.; Fletcher, J.W.; Mohler, J.W.

2006-01-01

Brook trout Salvelinus fontinalis, Atlantic salmon Salmo salar, coho salmon Oncorhynchus kisutch, and yellow perch Perca flavescens fed calcein for 5 d showed characteristic calcein scale marks 7-10 d postmarking. In fish fed 0.75 or 1.25 g of calcein per kilogram of feed, the percentage of fish that exhibited a calcein mark was 100% in brook trout, 93-98% in Atlantic salmon, 60% in yellow perch, and 0% in coho salmon. However, when coho salmon were fed 5.25 g calcein/kg feed, 100% marking was observed 7-10 d postmarking. Brook trout were successfully marked twice with distinct bands when fed calcein 5 months apart. Brook trout scale pixel luminosity increased as dietary calcein increased in experiment 2. For the second calcein mark, scale pixel luminosity from brook trout fed 1.25 g calcein/kg feed was numerically higher (P < 0.08) than scales from fish fed 0.75 g calcein/kg feed. Mean pixel luminosity of calcein-marked Atlantic salmon scales was 57.7 for fish fed 0.75 g calcein/kg feed and 55.2 for fish fed 1.25 g calcein/kg feed. Although feed acceptance presented a problem in yellow perch, these experiments provide evidence that dietary calcein is a viable tool for marking fish for stock identification. ?? Copyright by the American Fisheries Society 2006.

Stimulated emission in quantum well laser diodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blood, P.

1989-07-03

We observe that stimulated emission from inhomogeneously pumped quantum well laser diodes is shifted down in energy compared with the subband transition energy. Measured spontaneous emission spectra show that this stimulated emission is due to band-to-band transitions shifted by renormalization at high injected carrier densities, and we suggest that this same mechanism explains reported observations of stimulated emission from inhomogeneously photopumped structures which previously have been interpreted as evidence for longitudinal optic (LO) phonon participation. We show that LO phonon participation cannot account for the photon energy of stimulated emission from conventional homogeneously pumped quantum well laser diodes.

Variability of OH(3-1) and OH(6-2) emission altitude and volume emission rate from 2003 to 2011

NASA Astrophysics Data System (ADS)

Teiser, Georg; von Savigny, Christian

2017-08-01

In this study we report on variability in emission rate and centroid emission altitude of the OH(3-1) and OH(6-2) Meinel bands in the terrestrial nightglow based on spaceborne nightglow measurements with the SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) instrument on the Envisat satellite. The SCIAMACHY observations cover the time period from August 2002 to April 2012 and the nighttime observations used in this study are performed at 10:00 p.m. local solar time. Characterizing variability in OH emission altitude - particularly potential long-term variations - is important for an appropriate interpretation of ground-based OH rotational temperature measurements, because simultaneous observations of the vertical OH volume emission rate profile are usually not available for these measurements. OH emission altitude and vertically integrated emission rate time series with daily resolution for the OH(3-1) band and monthly resolution for the OH(6-2) band were analyzed using a standard multilinear regression approach allowing for seasonal variations, QBO-effects (Quasi-Biennial Oscillation), solar cycle (SC) variability and a linear long-term trend. The analysis focuses on low latitudes, where SCIAMACHY nighttime observations are available all year. The dominant sources of variability for both OH emission rate and altitude are the semi-annual and annual variations, with emission rate and altitude being highly anti-correlated. There is some evidence for a 11-year solar cycle signature in the vertically integrated emission rate and in the centroid emission altitude of both the OH(3-1) and OH(6-2) bands.

Yield of Unthinned Yellow-Poplar

Treesearch

Donald E. Beck; Lino Della-Bianca

1970-01-01

Cubic-foot and board-foot yields of unthinned yellow-poplar (Liriodendron Tulipiferi L.) stands are described in relation to stand age, site index, and number of trees per acre. The yield tables are based on analysis of diameter distributions and height-diameter relationships obtained from 141 natural, unthinned yellow-poplar stands in the...

Thermal emission from a metamaterial wire medium slab.

PubMed

D'Aguanno, G; Mattiucci, N; Alù, A; Argyropoulos, C; Foreman, J V; Bloemer, M J

2012-04-23

We investigate thermal emission from a metamaterial wire medium embedded in a dielectric host and highlight two different regimes for efficient emission, respectively characterized by broadband emission near the effective plasma frequency of the metamaterial, and by narrow-band resonant emission at the band-edge in the Bragg scattering regime. We discuss how to control the spectral position and relative strength of these two emission mechanisms by varying the geometrical parameters of the proposed metamaterial and its temperature. © 2012 Optical Society of America

Optical Band Gap Alteration of Graphene Oxide via Ozone Treatment.

PubMed

Hasan, Md Tanvir; Senger, Brian J; Ryan, Conor; Culp, Marais; Gonzalez-Rodriguez, Roberto; Coffer, Jeffery L; Naumov, Anton V

2017-07-25

Graphene oxide (GO) is a graphene derivative that emits fluorescence, which makes GO an attractive material for optoelectronics and biotechnology. In this work, we utilize ozone treatment to controllably tune the band gap of GO, which can significantly enhance its applications. Ozone treatment in aqueous GO suspensions yields the addition/rearrangement of oxygen-containing functional groups suggested by the increase in vibrational transitions of C-O and C=O moieties. Concomitantly it leads to an initial increase in GO fluorescence intensity and significant (100 nm) blue shifts in emission maxima. Based on the model of GO fluorescence originating from sp 2 graphitic islands confined by oxygenated addends, we propose that ozone-induced functionalization decreases the size of graphitic islands affecting the GO band gap and emission energies. TEM analyses of GO flakes confirm the size decrease of ordered sp 2 domains with ozone treatment, whereas semi-empirical PM3 calculations on model addend-confined graphitic clusters predict the inverse dependence of the band gap energies on sp 2 cluster size. This model explains ozone-induced increase in emission energies yielding fluorescence blue shifts and helps develop an understanding of the origins of GO fluorescence emission. Furthermore, ozone treatment provides a versatile approach to controllably alter GO band gap for optoelectronics and bio-sensing applications.

Optical Properties of ZnCdS:I Orange and ZnSTe:I White Thin Film Phosphor for High Ra White LED

NASA Astrophysics Data System (ADS)

Fujii, Satoshi; Tasaki, Norio; Shinomura, Naohiko; Kurai, Satoshi; Yamada, Yoichi; Taguchi, Tsunemasa

In order to develop visible thin film phosphors, we have for the first time prepared ZnCdS and ZnSTe doped with Iodine (I) using low-pressure MOCVD method. ZnCdS:I, of which Cd composition was calibrated to match the lattice constant to that of substrate and the band gap to absorption peak, showed a orange broad emission consist of yellow near band edge emission and red SA emission. Isoelectronic Te in ZnS indicates strong blue-green emissions, whilst I donor impurity in ZnS shows strong red SA emissions. A typical ZnSTe:I thin film shows two broad emission bands locating at around 500 and 680 nm, respectively, indicating Ra˜90. It was shown that high Ra thin film phosphor can be realized by single material (ZnSTe:I), and that MOCVD method is capable for controlling the thickness and doping profile to obtain uniform white emission pattern.

A thermochromic silver nanocluster exhibiting dual emission character

NASA Astrophysics Data System (ADS)

Xu, Qing-Qing; Dong, Xi-Yan; Huang, Ren-Wu; Li, Bo; Zang, Shuang-Quan; Mak, Thomas C. W.

2015-01-01

A Ag12(SCH2C10H7)6(CF3CO2)6(CH3CN)6 (1) nanocluster modified using naphthalen-2-yl-methanethiol was synthesized and structurally characterized by single crystal X-ray analysis. The targeted luminescent nanocluster displays dual emission with the property of reversible thermochromism spanning from red to bright yellow.A Ag12(SCH2C10H7)6(CF3CO2)6(CH3CN)6 (1) nanocluster modified using naphthalen-2-yl-methanethiol was synthesized and structurally characterized by single crystal X-ray analysis. The targeted luminescent nanocluster displays dual emission with the property of reversible thermochromism spanning from red to bright yellow. Electronic supplementary information (ESI) available: Experimental section and supporting Fig. S1-S6. CCDC 1004246. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4nr05122j

Investigations of the Nonlinear Optical Response of Composite and Photonic Band Gap Materials

DTIC Science & Technology

1998-11-01

M. J. Bloemer, M. Scalora , J. P. Dowling, and C. M. Bowden, "Measurement of spontaneous-emission enhancement near the one-dimensional photonic band...with applications to photonic band structures," Phys. Rev. A 46, 612 (1992). 5. M. Scalora , J. P. Dowling, M. Tocci, M. J. Bloemer, C. M. Bowden, and...J. W. Haus, "Dipole emission rates in one-dimensional photonic band-gap materials," Appl. Phys. B 60, S57 (1995). 6. J. P. Dowling, M. Scalora , M. J

Plant Guide: Yellow beeplant (Cleome lutea Hook)

Treesearch

Derek Tilley; Jim Cane; Loren St. John; Dan Ogle; Nancy Shaw

2012-01-01

Yellow beeplant is a valuable native forage species for bees wasps and butterflies. Over 140 species of native bees have been observed foraging for nectar or pollen on yellow beeplant in southern Utah (Cane, 2008). Yellow beeplant is an annual forb which could provide food to insects in the first growing season of a range seeding (Ogle and others, 2011a). This...

Why is my alfalfa yellow?

USDA-ARS?s Scientific Manuscript database

In 2016, many parts of the Midwest experienced far wetter than normal summer weather and by August or September, many growers were asking, “Why is my alfalfa yellow?” When all or part of an alfalfa field is yellow, it is a certain sign that something has gone wrong. In this case the problem in most ...

Financial maturity of yellow birch

Treesearch

William B. Leak

1969-01-01

The methods used to compute financial maturity of yellow birch sawtimber are similar to those used for paper birch sawtimber, except for minor differences in detail. The procedure followed for yellow-birch veneer-log trees was also similar, except that local veneer grades and local veneer-log prices were used as the basis for the financial maturity computations.

Density Measurements in Air by Optically Exciting the Cordes Bands of I2

NASA Technical Reports Server (NTRS)

Balla, R. Jeffrey; Exton, Reginald J.

2000-01-01

We describe an optical method based on laser-induced fluorescence for obtaining instantaneous measurements of density along a line in low-density air seeded with I2. The Cordes bands of I2 (D(sup 1)sigma(sup +, sub u)) left arrow X(sup 1)sigma(sup +, sub g)) are excited with a tunable ArF excimer laser. air densities in the range (0.1-6.5) x 10(exp 17) cm(exp -3) are measured over 295-583 K using the density-dependent emission ratio of two emission bands of I2; the 340 nm bands and the diffuse-structured McLennan bands near 320 nm.

Use of abnormal preprophase bands to decipher division plane determination

NASA Technical Reports Server (NTRS)

Granger, C.; Cyr, R.

2001-01-01

Many premitotic plant cells possess a cortical preprophase band of microtubules and actin filaments that encircles the nucleus. In vacuolated cells, the preprophase band is visibly connected to the nucleus by a cytoplasmic raft of actin filaments and microtubules termed the phragmosome. Typically, the location of the preprophase band and phragmosome corresponds to, and thus is thought to influence, the location of the cell division plane. To better understand the function of the preprophase band and phragmosome in orienting division, we used a green fluorescent protein-based microtubule reporter protein to observe mitosis in living tobacco bright yellow 2 cells possessing unusual preprophase bands. Observations of mitosis in these unusual cells support the involvement of the preprophase band/phragmosome in properly positioning the preprophase nucleus, influencing spindle orientation such that the cytokinetic phragmoplast initially grows in an appropriate direction, and delineating a region in the cell cortex that attracts microtubules and directs later stages of phragmoplast growth. Thus, the preprophase band/phragmosome appears to perform several interrelated functions to orient the division plane. However, functional information associated with the preprophase band is not always used or needed and there appears to be an age or distance-dependent character to the information. Cells treated with the anti-actin drug, latrunculin B, are still able to position the preprophase nucleus suggesting that microtubules may play a dominant role in premitotic positioning. Furthermore, in treated cells, spindle location and phragmoplast insertion are frequently abnormal suggesting that actin plays a significant role in nuclear anchoring and phragmoplast guidance. Thus, the microtubule and actin components of the preprophase band/phragmosome execute complementary activities to ensure proper orientation of the division plane.

Viscerotropic disease following yellow fever vaccination in Peru.

PubMed

Whittembury, Alvaro; Ramirez, Gladys; Hernández, Herminio; Ropero, Alba Maria; Waterman, Steve; Ticona, María; Brinton, Margo; Uchuya, Jorge; Gershman, Mark; Toledo, Washington; Staples, Erin; Campos, Clarense; Martínez, Mario; Chang, Gwong-Jen J; Cabezas, Cesar; Lanciotti, Robert; Zaki, Sherif; Montgomery, Joel M; Monath, Thomas; Hayes, Edward

2009-10-09

Five suspected cases of yellow fever vaccine-associated viscerotropic disease (YEL-AVD) clustered in space and time following a vaccination campaign in Ica, Peru in 2007. All five people received the same lot of 17DD live attenuated yellow fever vaccine before their illness; four of the five died of confirmed YEL-AVD. The surviving case was classified as probable YEL-AVD. Intensive investigation yielded no abnormalities of the implicated vaccine lot and no common risk factors. This is the first described space-time cluster of yellow fever viscerotropic disease involving more than two cases. Mass yellow fever vaccination should be avoided in areas that present extremely low risk of yellow fever.

Extreme Emission Line Galaxies in CANDELS: Broad-Band Selected, Star-Bursting Dwarf Galaxies at Z greater than 1

NASA Technical Reports Server (NTRS)

vanderWel, A.; Straughn, A. N.; Rix, H.-W.; Finkelstein, S. L.; Koekemoer, A. M.; Weiner, B. J.; Wuyts, S.; Bell, E. F.; Faber, S. M.; Trump, J. R.;

[Effect of transparent yellow and orange colored contact lenses on color discrimination in the yellow color range].

PubMed

Schürer, M; Walter, A; Brünner, H; Langenbucher, A

2015-08-01

Colored transparent filters cause a change in color perception and have an impact on the perceptible amount of different colors and especially on the ability to discriminate between them. Yellow or orange tinted contact lenses worn to enhance contrast vision by reducing or blocking short wavelengths also have an effect on color perception. The impact of the yellow and orange tinted contact lenses Wöhlk SPORT CONTRAST on color discrimination was investigated with the Erlangen colour measurement system in a study with 14 and 16 subjects, respectively. In relation to a yellow reference color located at u' = 0.2487/v' = 0.5433, measurements of color discrimination thresholds were taken in up to 6 different color coordinate axes. Based on these thresholds, color discrimination ellipses were calculated. These results are given in the Derrington, Krauskopf and Lennie (DKL) color system. Both contact lenses caused a shift of the reference color towards higher saturated colors. Color discrimination ability with the yellow and orange colored lenses was significantly enhanced along the blue-yellow axis in comparison to the reference measurements without a tinted filter. Along the red-green axis only the orange lens caused a significant reduction of color discrimination threshold distance to the reference color. Yellow and orange tinted contact lenses enhance the ability of color discrimination. If the transmission spectra and the induced changes are taken into account, these results can also be applied to other filter media, such as blue filter intraocular lenses.

High Pressure Noble Gas Alkali Vapor Mixtures and Their Visible and Infrared Excimer Bands.

DTIC Science & Technology

1980-02-01

Curry, and W. Bapper, "Visible emission bands of KXen polyatomic exciplexes ," Phys. Rev. Letters 41, 543 (1978). A. C. Tam, T. Yabuzaki, S. M. Curry...I178 Visible Emission Bands of KXe. Polyatomic Exciplexes ’. Yauviki.’ ) A. C. Tam, 0’ S. M. Curry, ( ) and W. liapper COdumble Ru’Iiati.op labor,, ,wy...giound electronic states. These temperature. " exciplex " molectle, are often gool laser species (2) The polyxetide band broadens substantially since the

Minimizing yellow-bellied sapsucker damage

Treesearch

Gayne G. Erdmann; Ralph M., Jr. Peterson

1992-01-01

The yellow-bellied sapsucker is a migratory woodpecker that feeds on a wide variety of orchard, shade, and forest trees. Instead of drilling holes to find insects like other woodpeckers, sapsuckers drill holes in living trees to feed on sap and phloem tissues. Yellow and paper birches are their favorite summer food sources on their nesting grounds in Upper Michigan and...

Silvical Characteristics of Yellow-Poplar

Treesearch

David F. Olson

1969-01-01

Yellow-poplar (Liriorlentlron tulipifera L.) is also commonly known as tulip poplar, tulip tree, white-poplar, whitewood, and "poplar" (60). It gets its name from the tulip-like flowers which it bears in the late spring. Because of the excellent form and rapid growth of the tree, plus the fine working qualities of the wood, yellow-poplar is one of the most...

Broadening emission band of Ba2B2O5: Dy3+ by codoping Ce3+ as sensitizer and its application to white LEDs

NASA Astrophysics Data System (ADS)

Xu, Shuchao; Wang, Zhijun; Li, Panlai; Li, Ting; Bai, Qiongyu; Yang, Zhiping

2018-06-01

In order to achieve broad-band white emitting phosphor, Ce3+/Dy3+ codoped Ba2B2O5 were synthesized by a solid-state method, and the luminescence property and energy transfer were discussed in detail. Dy3+ doped Ba2B2O5 shows white emission, and the two narrow peaks which are assigned to the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions of Dy3+ ions, respectively. When codoped Ce3+ as sensitizer, the broad-band white emission can be obtained by the energy transfer from Ce3+ to Dy3+ ions in Ba2B2O5, and the mechanism is the dipole-dipole interaction. And the CIE coordinates can be tuned from (0.2501, 0.2323) to (0.3422, 0.3799) by increase Dy3+ content. The emission peak blue-shift of Ce3+ ions in Ba2B2O5:Ce3+, Dy3+ was observed from the thermal spectra, and the mechanism was analyzed. A white light emitting diodes (LEDs) can be fabricated Ba2B2O5:Ce3+, Dy3+ with 380 nm chip, and the results show that the phosphor may be a potential application in this field.

Thermal Infrared Spectral Band Detection Limits for Unidentified Surface Materials

NASA Technical Reports Server (NTRS)

Kirkland, Laurel E.; Herr, Kenneth C.; Salisbury, John W.

2001-01-01

Infrared emission spectra recorded by airborne or satellite spectrometers can be searched for spectral features to determine the composition of rocks on planetary surfaces. Surface materials are identified by detections of characteristic spectral bands. We show how to define whether to accept an observed spectral feature as a detection when the target material is unknown. We also use remotely sensed spectra measured by the Thermal Emission Spectrometer (TES) and the Spatially Enhanced Broadband Array Spectrograph System to illustrate the importance of instrument parameters and surface properties on band detection limits and how the variation in signal-to-noise ratio with wavelength affects the bands that are most detectable for a given instrument. The spectrometer's sampling interval, spectral resolution, signal-to-noise ratio as a function of wavelength, and the sample's surface properties influence whether the instrument can detect a spectral feature exhibited by a material. As an example, in the 6-13 micrometer wavelength region, massive carbonates exhibit two bands: a very strong, broad feature at approximately 6.5 micrometers and a less intense, sharper band at approximately 11.25 micrometers. Although the 6.5-micrometer band is stronger and broader in laboratory-measured spectra, the 11.25-micrometer band will cause a more detectable feature in TES spectra.

Peripherally hydrogenated neutral polycyclic aromatic hydrocarbons as carriers of the 3 micron interstellar infrared emission complex: results from single-photon infrared emission spectroscopy

NASA Technical Reports Server (NTRS)

Wagner, D. R.; Kim, H. S.; Saykally, R. J.

2000-01-01

Infrared emission spectra of five gas-phase UV laser-excited polycyclic aromatic hydrocarbons (PAHs) containing aliphatic hydrogens are compared with the main 3.3 microns and associated interstellar unidentified infrared emission bands (UIRs). We show that neutral PAHs can account for the majority of the 3 microns emission complex while making little contribution to the other UIR bands; peripherally hydrogenated PAHs produce a better match to astrophysical data than do those containing methyl side groups; 3.4 microns plateau emission is shown to be a general spectral feature of vibrationally excited PAHs containing aliphatic hydrogens, especially those containing methyl groups; and finally, hot-band and overtone emissions arising from aromatic C-H vibrations are not observed in laboratory emission spectra, and therefore, in contrast to current assignments, are not expected to be observed in the UIRs.

A LIGHT CURVE ANALYSIS OF CLASSICAL NOVAE: FREE-FREE EMISSION VERSUS PHOTOSPHERIC EMISSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hachisu, Izumi; Kato, Mariko, E-mail: hachisu@ea.c.u-tokyo.ac.jp, E-mail: mariko@educ.cc.keio.ac.jp

2015-01-10

We analyzed light curves of seven relatively slower novae, PW Vul, V705 Cas, GQ Mus, RR Pic, V5558 Sgr, HR Del, and V723 Cas, based on an optically thick wind theory of nova outbursts. For fast novae, free-free emission dominates the spectrum in optical bands rather than photospheric emission, and nova optical light curves follow the universal decline law. Faster novae blow stronger winds with larger mass-loss rates. Because the brightness of free-free emission depends directly on the wind mass-loss rate, faster novae show brighter optical maxima. In slower novae, however, we must take into account photospheric emission because of theirmore » lower wind mass-loss rates. We calculated three model light curves of free-free emission, photospheric emission, and their sum for various white dwarf (WD) masses with various chemical compositions of their envelopes and fitted reasonably with observational data of optical, near-IR (NIR), and UV bands. From light curve fittings of the seven novae, we estimated their absolute magnitudes, distances, and WD masses. In PW Vul and V705 Cas, free-free emission still dominates the spectrum in the optical and NIR bands. In the very slow novae, RR Pic, V5558 Sgr, HR Del, and V723 Cas, photospheric emission dominates the spectrum rather than free-free emission, which makes a deviation from the universal decline law. We have confirmed that the absolute brightnesses of our model light curves are consistent with the distance moduli of four classical novae with known distances (GK Per, V603 Aql, RR Pic, and DQ Her). We also discussed the reason why the very slow novae are about ∼1 mag brighter than the proposed maximum magnitude versus rate of decline relation.« less

Effect of narrow band nonuniformity on unsteady heat up of water vapor under radiation-conduction combined heat transfer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okamoto, Tatsuyuki; Tanaka, Tomohiro; Morimune, Atsushi

Effect of narrow band nonuniformity on unsteady heat up process of water vapor under radiation-conduction combined heat transfer is examined by comparing the result of numerical simulations with and without incorporation of narrow band nonuniformity. The authors propose a rational and comprehensive computational approach for incorporating the narrow band nonuniformity into numerical simulations of radiative heat transfer when the considered field is nonisothermal. Results of examination exhibited that the contribution of radiative heat transfer to the heat up rate of water vapor may be almost twice overestimated, if the narrow band nonuniformity effect is neglected. Separate analyses of radiative energymore » attributed to wall emission and gas emission clarified that the absorption of wall emission is overestimated and, on the contrary, the absorption of radiation energy emitted by water vapor itself is underestimated if the narrow band nonuniformity is neglected. The reason why such over- or under-estimation is induced is understood by examining the influence of line overlap parameter on the transmittance averaged within a narrow band. Smaller value of line overlap parameter {gamma}/d means more violent narrow band nonuniformity. The broken lines show the narrow band transmittance for flat incident power spectrum, and the solid lines show that for the radiative emission from the absorbing gas itself. It is also clarified that the disregard of the narrow band nonuniformity give rise to serious error in the estimation of absorption rate of wall and gas emission even in the case where the disregard of narrow band nonuniformity bring little change to the temperature distribution. The results illustrated in this paper suggest that the narrow band nonuniformity should not be neglected.« less

S-NPP VIIRS thermal emissive bands on-orbit calibration and performance

NASA Astrophysics Data System (ADS)

Efremova, Boryana; McIntire, Jeff; Moyer, David; Wu, Aisheng; Xiong, Xiaoxiong

2014-09-01

Presented is an assessment of the on-orbit radiometric performance of the thermal emissive bands (TEB) of the Suomi National Polar-orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) instrument based on data from the first 2 years of operations—from 20 January 2012 to 20 January 2014. The VIIRS TEB are calibrated on orbit using a V-grooved blackbody (BB) as a radiance source. Performance characteristics trended over the life of the mission include the F factor—a measure of the gain change of the TEB detectors; the Noise Equivalent differential Temperature (NEdT)—a measure of the detector noise; and the detector offset and nonlinear terms trended at the quarterly performed BB warm-up cool-down cycles. We find that the BB temperature is well controlled and stable within the 30mK requirement. The F factor trends are very stable and showing little degradation (within 0.8%). The offsets and nonlinearity terms are also without noticeable drifts. NEdT is stable and does not show any trend. Other TEB radiometric calibration-related activities discussed include the on-orbit assessment of the response versus scan-angle functions and an approach to improve the M13 low-gain calibration using onboard lunar measurements. We conclude that all the assessed parameters comply with the requirements, and the TEB provide radiometric measurements with the required accuracy.

Dermatology Internet Yellow Page advertising.

PubMed

Francis, Shayla; Kozak, Katarzyna Z; Heilig, Lauren; Lundahl, Kristy; Bowland, Terri; Hester, Eric; Best, Arthur; Dellavalle, Robert P

2006-07-01

Patients may use Internet Yellow Pages to help select a physician. We sought to describe dermatology Internet Yellow Page advertising. Dermatology advertisements in Colorado, California, New York, and Texas at 3 Yellow Page World Wide Web sites were systematically examined. Most advertisements (76%; 223/292) listed only one provider, 56 listed more than one provider, and 13 listed no practitioner names. Five advertisements listed provider names without any credentialing letters, 265 listed at least one doctor of medicine or osteopathy, and 9 listed only providers with other credentials (6 doctors of podiatric medicine and 3 registered nurses). Most advertisements (61%; 179/292) listed a doctor of medicine or osteopathy claiming board certification, 78% (139/179) in dermatology and 22% (40/179) in other medical specialties. Four (1%; 4/292) claims of board certification could not be verified (one each in dermatology, family practice, dermatologic/cosmetologic surgery, and laser surgery). Board certification could be verified for most doctors of medicine and osteopathy not advertising claims of board certification (68%; 41/60; 32 dermatology, 9 other specialties). A total of 50 advertisements (17%) contained unverifiable or no board certification information, and 47 (16%) listed a physician with verifiable board certification in a field other than dermatology. All Internet Yellow Page World Wide Web sites and all US states were not examined. Nonphysicians, physicians board certified in medical specialties other than dermatology, and individuals without verifiable board certification in any medical specialty are advertising in dermatology Internet Yellow Pages. Many board-certified dermatologists are not advertising this certification.

21 CFR 573.1020 - Yellow prussiate of soda.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.1020 Yellow prussiate of soda. Yellow prussiate of soda (sodium... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Yellow prussiate of soda. 573.1020 Section 573...

21 CFR 573.1020 - Yellow prussiate of soda.

Code of Federal Regulations, 2012 CFR

2012-04-01

...) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.1020 Yellow prussiate of soda. Yellow prussiate of soda (sodium... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Yellow prussiate of soda. 573.1020 Section 573...

21 CFR 573.1020 - Yellow prussiate of soda.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.1020 Yellow prussiate of soda. Yellow prussiate of soda (sodium... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Yellow prussiate of soda. 573.1020 Section 573...

21 CFR 573.1020 - Yellow prussiate of soda.

Code of Federal Regulations, 2013 CFR

2013-04-01

...) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.1020 Yellow prussiate of soda. Yellow prussiate of soda (sodium... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Yellow prussiate of soda. 573.1020 Section 573...

21 CFR 573.1020 - Yellow prussiate of soda.

Code of Federal Regulations, 2011 CFR

2011-04-01

...) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.1020 Yellow prussiate of soda. Yellow prussiate of soda (sodium... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Yellow prussiate of soda. 573.1020 Section 573...

Highly Efficient Defect Emission from ZnO:Zn and ZnO:S Powders

NASA Astrophysics Data System (ADS)

Everitt, Henry

2013-03-01

Bulk Zinc Oxide (ZnO) is a wide band gap semiconductor with an ultraviolet direct band gap energy of 3.4 eV and a broad, defect-related visible wavelength emission band centered near 2 eV. We have shown that the external quantum efficiency can exceed 50% for this nearly white emission band that closely matches the human dark-adapted visual response. To explore the potential of ZnO as a rare earth-free white light phosphor, we investigated the mechanism of efficient defect emission in three types of ZnO powders: unannealed, annealed, and sulfur-doped. Annealing and sulfur-doping of ZnO greatly increase the strength of defect emission while suppressing the UV band edge emission. Continuous wave and ultrafast one- and two-photon excitation spectroscopy are used to examine the defect emission mechanism. Low temperature photoluminescence (PL) and PL excitation (PLE) spectra were measured for all three compounds, and it was found that bound excitons mediate the defect emission. Temperature-dependent PLE spectra for the defect and band edge emission were measured to estimate trapping and activation energies of the bound excitons and clarify the role they play in the defect emission. Time-resolved techniques were used to ascertain the role of exciton diffusion, the effects of reabsorption, and the spatial distributions of radiative and non-radiative traps. In unannealed ZnO we find that defect emission is suppressed and UV band edge emission is inefficient (< 2%) because of reabsorption and non-radiative recombination due to a high density of non-radiative bulk traps. By annealing ZnO, bulk trap densities are reduced, and a high density of defects responsible for the broad visible emission are created near the surface. Interestingly, nearly identical PLE spectra are found for both the band edge and the defect emission, one of many indications that the defect emission is deeply connected to bound excitons. Quantum efficiency, also measured as a function of excitation

Carbon stars with alpha-C:H emission

NASA Technical Reports Server (NTRS)

Gerbault, Florence; Goebel, John H.

1989-01-01

Many carbon stars in the IRS low resolution spectra (LRS) catalog were found which display emission spectra that compare favorable with the absorption spectrum of alpha-C:H. These stars have largely been classified as 4X in the LRS which has led to their interpretation by others in terms of displaying a mixture of the UIRF's 8.6 micron band and SiC at 11.5 microns. It was also found that many of these stars have a spectral upturn at 20+ microns which resembles the MgS band seen in carbon stars and planetary nebulae. It was concluded that this group of carbon stars will evolve into planetary nebulae like NGC 7027 and IC 418. In the presence of hard ultraviolet radiation the UIRF's will light up and be displayed as narrow emission bands on top of the broad alpha-C:H emission bands.

Yellow fever: the recurring plague.

PubMed

Tomori, Oyewale

2004-01-01

Despite the availability of a safe and efficacious vaccine, yellow fever (YF) remains a disease of significant public health importance, with an estimated 200,000 cases and 30,000 deaths annually. The disease is endemic in tropical regions of Africa and South America; nearly 90% of YF cases and deaths occur in Africa. It is a significant hazard to unvaccinated travelers to these endemic areas. Virus transmission occurs between humans, mosquitoes, and monkeys. The mosquito, the true reservoir of YF, is infected throughout its life, and can transmit the virus transovarially through infected eggs. Man and monkeys, on the other hand, play the role of temporary amplifiers of the virus available for mosquito infection. Recent increases in the density and distribution of the urban mosquito vector, Aedes aegypti, as well as the rise in air travel increase the risk of introduction and spread of yellow fever to North and Central America, the Caribbean, the Middle East, Asia, Australia, and Oceania. It is an acute infectious disease characterized by sudden onset with a two-phase development, separated by a short period of remission. The clinical spectrum of yellow fever varies from very mild, nonspecific, febrile illness to a fulminating, sometimes fatal disease with pathognomic features. In severe cases, jaundice, bleeding diathesis, with hepatorenal involvement are common. The case fatality rate of severe yellow fever is 50% or higher. The pathogenesis and pathophysiology of the disease are poorly understood and have not been the subject of modern clinical research. There is no specific treatment for YF, making the management of YF patients extremely problematic. YF is a zoonotic disease that cannot be eradicated, therefore instituting preventive vaccination through routine childhood vaccination in endemic countries, can significantly reduce the burden of the disease. The distinctive properties of lifelong immunity after a single dose of yellow fever vaccination are the

Tunable emission in lanthanide coordination polymer gels based on a rationally designed blue emissive gelator.

PubMed

Sutar, Papri; Suresh, Venkata M; Maji, Tapas Kumar

2015-06-18

Rational design and synthesis of a new low molecular weight gelator (LMWG) having 9,10-diphenylanthracene core and terminal terpyridine is reported. Tb(III) and Eu(III) ion coordination to a LMWG results in green and pink emissive coordination polymer gels, respectively, with coiled nanofiber morphology. Further, control over stoichiometry of LMWG:Tb(III):Eu(III) leads to yellow and white light emitting bimetallic gels.

Impact of surface roughness on L-band emissivity of the sea ice

NASA Astrophysics Data System (ADS)

Miernecki, M.; Kaleschke, L.; Hendricks, S.; Søbjærg, S. S.

2015-12-01

In March 2014 a joint experiment IRO2/SMOSice was carried out in the Barents Sea. R/V Lance equipped with meteorological instruments, electromagnetic sea ice thickness probe and engine monitoring instruments, was performing a series of tests in different ice conditions in order to validate the ice route optimization (IRO) system, advising on his route through pack ice. In parallel cal/val activities for sea ice thickness product obtained from SMOS (Soil Moisture and Ocean Salinity mission) L-band radiometer were carried out. Apart from helicopter towing the EMbird thickness probe, Polar 5 aircraft was serving the area during the experiment with L-band radiometer EMIRAD2 and Airborne Laser Scanner (ALS) as primary instruments. Sea ice Thickness algorithm using SMOS brightness temperature developed at University of Hamburg, provides daily maps of thin sea ice (up to 0.5-1 m) in polar regions with resolution of 35-50 km. So far the retrieval method was not taking into account surface roughness, assuming that sea ice is a specular surface. Roughness is a stochastic process that can be characterized by standard deviation of surface height σ and by shape of the autocorrelation function R to estimate it's vertical and horizontal scales respectively. Interactions of electromagnetic radiation with the surface of the medium are dependent on R and σ and they scales with respect to the incident wavelength. During SMOSice the radiometer was observing sea ice surface at two incidence angles 0 and 40 degrees and simultaneously the surface elevation was scanned with ALS with ground resolution of ~ 0.25 m. This configuration allowed us to calculate σ and R from power spectral densities of surface elevation profiles and quantify the effect of surface roughness on the emissivity of the sea ice. First results indicate that Gaussian autocorrelation function is suitable for deformed ice, for other ice types exponential function is the best fit.

Multicolor tuning towards single red-emission band of upconversion nanoparticles for tunable optical component and optical/x-ray imaging agents via Ce(3+) doping.

PubMed

Yi, Zhigao; Zeng, Tianmei; Xu, Yaru; Lu, Wei; Qian, Chao; Liu, Hongrong; Zeng, Songjun; Hao, Jianhua

2015-09-25

A simple strategy of Ce(3+) doping is proposed to realize multicolor tuning and predominant red emission in BaLnF5:Yb(3+)/Ho(3+) (Ln(3+) = Gd(3+), Y(3+), Yb(3+)) systems. A tunable upconversion (UC) multicolor output from green/yellow to red can be readily achieved in a fixed Yb(3+)/Ho(3+) composition by doping Ce(3+), providing an effective route for multicolor tuning widely used for various optical components. Moreover, compared with Ce(3+)-free UC nanoparticles (UCNPs), a remarkable enhancement of the red-to-green (R/G) ratio is observed by doping 30% Ce(3+), arising from the two largely promoted cross-relaxation (CR) processes between Ce(3+) and Ho(3+). UCNPs with pure red emission are selected as in vivo UC bioimaging agents, demonstrating the merits of deep penetration depth, the absence of autofluorescence and high contrast in small animal bioimaging. Moreover, such fluorescence imaging nanoprobes can also be used as contrast agents for three-dimensional (3D) x-ray bioimaging by taking advantage of the high K-edge values and x-ray absorption coefficients of Ba(2+), Gd(3+), and Ce(3+) in our designed nanoprobes. Thus, the simultaneous realization of multicolor output, highly enhanced R/G ratio, and predominant red emission makes the Ce(3+)-doped UCNPs very useful for widespread applications in optical components and bioimaging.

Influence of the Yellow Sea Warm Current on phytoplankton community in the central Yellow Sea

NASA Astrophysics Data System (ADS)

Liu, Xin; Chiang, Kuo-Ping; Liu, Su-Mei; Wei, Hao; Zhao, Yuan; Huang, Bang-Qin

2015-12-01

In early spring, a hydrological front emerges in the central Yellow Sea, resulting from the intrusion of the high temperature and salinity Yellow Sea Warm Current (YSWC). The present study, applying phytoplankton pigments and flow cytometry measurements in March of 2007 and 2009, focuses on the biogeochemical effects of the YSWC. The nutrients fronts were coincident with the hydrological front, and a positive linear relationship between nitrate and salinity was found in the frontal area. This contrast with the common situation of coastal waters where high salinity values usually correlate with poor nutrients. We suggested nutrient concentrations of the YSWC waters might have been enhanced by mixing with the local nutrient-rich waters when it invaded the Yellow Sea from the north of the Changjiang estuary. In addition, our results indicate that the relative abundance of diatoms ranged from 26% to 90%, showing a higher value in the YSCC than in YSWC waters. Similar distributions were found between diatoms and dinoflagellates, however the cyanobacteria and prasinophytes showed an opposite distribution pattern. Good correlations were found between the pigments and flow cytometry observations on the picophytoplankton groups. Prasinophytes might be the major contributor to pico-eukaryotes in the central Yellow Sea as similar distributional patterns and significant correlations between them. It seems that the front separates the YSWC from the coastal water, and different phytoplankton groups are transported in these water masses and follow their movement. These results imply that the YSWC plays important roles in the distribution of nutrients, phytoplankton biomass and also in the community structure of the central Yellow Sea.

49 CFR 173.188 - White or yellow phosphorus.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false White or yellow phosphorus. 173.188 Section 173... Class 7 § 173.188 White or yellow phosphorus. Phosphorus, white or yellow, when offered for... pound) of phosphorus with screw-top closures; or (2) Steel drums (1A1) not over 250 L (66 gallons...

49 CFR 173.188 - White or yellow phosphorus.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false White or yellow phosphorus. 173.188 Section 173... Class 7 § 173.188 White or yellow phosphorus. Phosphorus, white or yellow, when offered for... pound) of phosphorus with screw-top closures; or (2) Steel drums (1A1) not over 250 L (66 gallons...

Radiative recombination in GaN/InGaN heterojunction bipolar transistors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kao, Tsung-Ting; Lee, Yi-Che; Kim, Hee-Jin

2015-12-14

We report an electroluminescence (EL) study on npn GaN/InGaN heterojunction bipolar transistors (HBTs). Three radiative recombination paths are resolved in the HBTs, corresponding to the band-to-band transition (3.3 eV), conduction-band-to-acceptor-level transition (3.15 eV), and yellow luminescence (YL) with the emission peak at 2.2 eV. We further study possible light emission paths by operating the HBTs under different biasing conditions. The band-to-band and the conduction-band-to-acceptor-level transitions mostly arise from the intrinsic base region, while a defect-related YL band could likely originate from the quasi-neutral base region of a GaN/InGaN HBT. The I{sub B}-dependent EL intensities for these three recombination paths are discussed. The resultsmore » also show the radiative emission under the forward-active transistor mode operation is more effective than that using a diode-based emitter due to the enhanced excess electron concentration in the base region as increasing the collector current increases.« less

Complex organic matter in space: about the chemical composition of carriers of the Unidentified Infrared Bands (UIBs) and protoplanetary emission spectra recorded from certain astrophysical objects.

PubMed

Cataldo, Franco; Keheyan, Yeghis; Heymann, Dieter

2004-02-01

In this communication we present the basic concept that the pure PAHs (Polycyclic Aromatic Hydrocarbons) can be considered only the ideal carriers of the UIBs (Unidentified Infrared Bands), the emission spectra coming from a large variety of astronomical objects. Instead we have proposed that the carriers of UIBs and of protoplanetary nebulae (PPNe) emission spectra are much more complex molecular mixtures possessing also complex chemical structures comparable to certain petroleum fractions obtained from the petroleum refining processes. The demonstration of our proposal is based on the comparison between the emission spectra recorded from the protoplanetary nebulae (PPNe) IRAS 22272+ 5435 and the infrared absorption spectra of certain 'heavy' petroleum fractions. It is shown that the best match with the reference spectrum is achieved by highly aromatic petroleum fractions. It is shown that the selected petroleum fractions used in the present study are able to match the band pattern of anthracite coal. Coal has been proposed previously as a model for the PPNe and UIBs but presents some drawbacks which could be overcome by adopting the petroleum fractions as model for PPNe and UIBs in place of coal. A brief discussion on the formation of the petroleum-like fractions in PPNe objects is included.

21 CFR 137.280 - Bolted yellow corn meal.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Bolted yellow corn meal. 137.280 Section 137.280... Flours and Related Products § 137.280 Bolted yellow corn meal. Bolted yellow corn meal conforms to the definition and standard of identity prescribed by § 137.255 for bolted white corn meal except that cleaned...

21 CFR 137.280 - Bolted yellow corn meal.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Bolted yellow corn meal. 137.280 Section 137.280... Flours and Related Products § 137.280 Bolted yellow corn meal. Bolted yellow corn meal conforms to the definition and standard of identity prescribed by § 137.255 for bolted white corn meal except that cleaned...

Biologically inspired band-edge laser action from semiconductor with dipole-forbidden band-gap transition.

PubMed

Wang, Cih-Su; Liau, Chi-Shung; Sun, Tzu-Ming; Chen, Yu-Chia; Lin, Tai-Yuan; Chen, Yang-Fang

2015-03-11

A new approach is proposed to light up band-edge stimulated emission arising from a semiconductor with dipole-forbidden band-gap transition. To illustrate our working principle, here we demonstrate the feasibility on the composite of SnO2 nanowires (NWs) and chicken albumen. SnO2 NWs, which merely emit visible defect emission, are observed to generate a strong ultraviolet fluorescence centered at 387 nm assisted by chicken albumen at room temperature. In addition, a stunning laser action is further discovered in the albumen/SnO2 NWs composite system. The underlying mechanism is interpreted in terms of the fluorescence resonance energy transfer (FRET) from the chicken albumen protein to SnO2 NWs. More importantly, the giant oscillator strength of shallow defect states, which is served orders of magnitude larger than that of the free exciton, plays a decisive role. Our approach therefore shows that bio-materials exhibit a great potential in applications for novel light emitters, which may open up a new avenue for the development of bio-inspired optoelectronic devices.

Image plane detector spectrophotometer - Application to O2 atmospheric band nightglow

NASA Technical Reports Server (NTRS)

Luo, Mingzhao; Yee, Jeng-Hwa; Hays, Paul B.

1988-01-01

A new variety of low resolution spectrometer is described. This device, an image plane detector spectrophotometer, has high sensitivity and modest resolution sufficient to determine the rotational temperature and brightness of molecular band emissions. It uses an interference filter as a dispersive element and a multichannel image plane detector as the photon collecting device. The data analysis technqiue used to recover the temperature of the emitter and the emission brightness is presented. The atmospheric band of molecular oxygen is used to illustrate the use of the device.

Photoexcited emission efficiencies of zinc oxide

NASA Astrophysics Data System (ADS)

Foreman, John Vincent

Optoelectronic properties of the II-VI semiconductor zinc oxide (ZnO) have been studied scientifically for almost 60 years; however, many fundamental questions remain unanswered about its two primary emission bands--the exciton-related luminescence in the ultraviolet and the defect-related emission band centered in the green portion of the visible spectrum. The work in this dissertation was motivated by the surprising optical properties of a ZnO nanowire sample grown by the group of Prof. Jie Liu, Department of Chemistry, Duke University. We found that this nanowire sample exhibited defect-related green/white emission of unprecedented intensity relative to near-band-edge luminescence. The experimental work comprising this dissertation was designed to explain the optical properties of this ZnO nanowire sample. Understanding the physics underlying such exceptional intensity of green emission addresses many of the open questions of ZnO research and assesses the possibility of using ZnO nanostructures as an ultraviolet-excited, broadband visible phosphor. The goal of this dissertation is to provide insight into what factors influence the radiative and nonradiative recombination efficiencies of ZnO by characterizing simultaneously the optical properties of the near-band-edge ultraviolet and the defect-related green emission bands. Specifically, we seek to understand the mechanisms of ultraviolet and green emission, the mechanism of energy transfer between them, and the evolution of their emission efficiencies with parameters such as excitation density and sample temperature. These fundamental but unanswered questions of ZnO emission are addressed here by using a novel combination of ultrafast spectroscopic techniques in conjunction with a systematic set of ZnO samples. Through this systematic investigation, ZnO may be realistically assessed as a potential green/white light phosphor. Photoluminescence techniques are used to characterize the thermal quenching behavior of

Extreme Emission Line Galaxies in CANDELS: Broad-Band Selected, Star-Bursting Dwarf Galaxies at Z greater than 1

NASA Technical Reports Server (NTRS)

VanDerWel, A.; Straughn, A. N.; Rix, H.-W.; Finkelstein, S. L.; Koekemoer, A. M.; Weiner, B. J.; Wuyts, S.; Bell, E. F.; Faber, S. M.; Trump, J. R.;

Ground-based K-band detection of thermal emission from the exoplanet TrES-3b

NASA Astrophysics Data System (ADS)

de Mooij, E. J. W.; Snellen, I. A. G.

2009-01-01

Context: Secondary eclipse measurements of transiting extrasolar planets with the Spitzer Space Telescope have yielded several direct detections of thermal exoplanet light. Since Spitzer operates at wavelengths longward of 3.6 μm, arguably one of the most interesting parts of the planet spectrum (from 1 to 3 μm) is inaccessible with this satellite. This region is at the peak of the planet's spectral energy distribution and is also the regime where molecular absorption bands can significantly influence the measured emission. Aims: So far, 2.2 μm K-band secondary eclipse measurements, which are possible from the ground, have not yet lead to secure detections. The aim of this paper is to measure the secondary eclipse of the very hot Jupiter TrES-3b in K-band, and in addition to observe its transit, to obtain an accurate planet radius in the near infrared. Methods: We have used the william herschell telescope (WHT) to observe the secondary eclipse, and the united kingdom infrared telescope (UKIRT) to observe the transit of TrES-3b. Both observations involved significant defocusing of the telescope, aimed to produce high-cadence time series of several thousand frames at high efficiency, with the starlight spread out over many pixels. Results: We detect the secondary eclipse of TrES-3b with a depth of -0.241 ± 0.043% (~6σ). This corresponds to a day-side brightness temperature of TB(2.2 μm) = 2040 ± 185 K, which is consistent with current models of the physical properties of this planet's upper atmosphere. The centre of the eclipse seems slightly offset from phase φ=0.5 by Δφ = -0.0042 ± 0.0027, which could indicate that the orbit of TrES-3b is non-circular. Analysis of the transit data shows that TrES-3b has a near-infrared radius of 1.338 ± 0.016 R_Jup, showing no significant deviation from optical measurements.

Yellow Fever Outbreak, Southern Sudan, 2003

PubMed Central

Onyango, Clayton O.; Grobbelaar, Antoinette A.; Gibson, Georgina V.F.; Sang, Rosemary C.; Sow, Abdourahmane; Swanepoel, Robert

2004-01-01

In May 2003, an outbreak of fatal hemorrhagic fever, caused by yellow fever virus, occurred in southern Sudan. Phylogenetic analysis showed that the virus belonged to the East African genotype, which supports the contention that yellow fever is endemic in East Africa with the potential to cause large outbreaks in humans. PMID:15498174

Various Measures of the Effectiveness of Yellow Goggles

DTIC Science & Technology

1980-10-08

technique which is widely used r.o improve vision under these conditions is the use of yellow goggles. Skiers commonly don yellow goggles...different laboratory studies are presented. Two of the studies were of depth perception, since skiers believe that yellow goggles help them...selected for measurement because of practical considerations and theoretical implications. EXPERIMENTS ON DEPTH PERCEPTION Background Since skiers

Narrow-band generation in random distributed feedback fiber laser.

PubMed

Sugavanam, Srikanth; Tarasov, Nikita; Shu, Xuewen; Churkin, Dmitry V

2013-07-15

Narrow-band emission of spectral width down to ~0.05 nm line-width is achieved in the random distributed feedback fiber laser employing narrow-band fiber Bragg grating or fiber Fabry-Perot interferometer filters. The observed line-width is ~10 times less than line-width of other demonstrated up to date random distributed feedback fiber lasers. The random DFB laser with Fabry-Perot interferometer filter provides simultaneously multi-wavelength and narrow-band (within each line) generation with possibility of further wavelength tuning.

Infrared emission spectra of candidate interstellar aromatic molecules

NASA Technical Reports Server (NTRS)

Schlemmer, S.; Balucani, N.; Wagner, D. R.; Steiner, B.; Saykally, R. J.

1996-01-01

Interstellar dust is responsible, through surface reactions, for the creation of molecular hydrogen, the main component of the interstellar clouds in which new stars form. Intermediate between small, gas-phase molecules and dust are the polycyclic aromatic hydrocarbons (PAHs). Such molecules could account for 2-30% of the carbon in the Galaxy, and may provide nucleation sites for the formation of carbonaceous dust. Although PAHs have been proposed as the sources of the unidentified infrared emission bands that are observed in the spectra of a variety of interstellar sources, the emission characteristics of such molecules are still poorly understood. Here we report laboratory emission spectra of several representative PAHs, obtained in conditions approximating those of the interstellar medium, and measured over the entire spectral region spanned by the unidentified infrared bands. We find that neutral PAHs of small and moderate size can at best make only a minor contribution to these emission bands. Cations of these molecules, as well as much larger PAHs and their cations, remain viable candidates for the sources of these bands.

Direct Band Gap Wurtzite Gallium Phosphide Nanowires

PubMed Central

2013-01-01

The main challenge for light-emitting diodes is to increase the efficiency in the green part of the spectrum. Gallium phosphide (GaP) with the normal cubic crystal structure has an indirect band gap, which severely limits the green emission efficiency. Band structure calculations have predicted a direct band gap for wurtzite GaP. Here, we report the fabrication of GaP nanowires with pure hexagonal crystal structure and demonstrate the direct nature of the band gap. We observe strong photoluminescence at a wavelength of 594 nm with short lifetime, typical for a direct band gap. Furthermore, by incorporation of aluminum or arsenic in the GaP nanowires, the emitted wavelength is tuned across an important range of the visible light spectrum (555–690 nm). This approach of crystal structure engineering enables new pathways to tailor materials properties enhancing the functionality. PMID:23464761

Spectroscopic behavior of composition dependent Dy3+ doped alkali fluoroborophosphate glasses

NASA Astrophysics Data System (ADS)

Raj, V. Anthony; Maheshvaran, K.; D'Silva, A. Josuva; Rayappan, I. Arul

2018-04-01

A new series of Dy3+ doped Alkali fluoroborophosphate glasses were prepared following conventional melt quenching technique and characterized using optical absorption and luminescence measurements. The nature of the metal-ligand bonding and the electronic band structure has been investigated using the absorption spectra. The Judd-Oflet (JO) intensity parameters (Ω2, Ω4 and Ω6) were evaluated and the experimental oscillator strength values were also calculated. The luminescence spectra exhibit two visible bands 4F9/2→6H15/2 (Blue) and 4F9/2→6H13/2 (Yellow) respectively. The radiative properties such as peak wavelength and effective band width for the emission transition were calculated. The yellow to blue (Y/B) ratios and color coordinates have been calculated from the luminescence spectra and the utility of the present glasses for white LED applications.

Multi-photon excited coherent random laser emission in ZnO powders

NASA Astrophysics Data System (ADS)

Tolentino Dominguez, Christian; Gomes, Maria De A.; Macedo, Zélia S.; de Araújo, Cid B.; Gomes, Anderson S. L.

2014-11-01

We report the observation and analysis of anti-Stokes coherent random laser (RL) emission from zinc oxide (ZnO) powders excited by one-, two- or three-photon femtosecond laser radiation. The ZnO powders were produced via a novel proteic sol-gel, low-cost and environmentally friendly route using coconut water in the polymerization step of the metal precursor. One- and two-photon excitation at 354 nm and 710 nm, respectively, generated single-band emissions centred at about 387 nm. For three-photon excitation, the emission spectra showed a strong ultraviolet (UV) band (380-396 nm) attributed to direct three-photon absorption from the valence band to the conduction band. The presence of an intensity threshold and a bandwidth narrowing of the UV band from about 20 to 4 nm are clear evidence of RL action. The observation of multiple sub-nanometre narrow peaks in the emission spectra for excitation above the RL threshold is consistent with random lasing by coherent feedback.

Radio Emission from the Exoplanetary System ɛ Eridani

NASA Astrophysics Data System (ADS)

Bastian, T. S.; Villadsen, J.; Maps, A.; Hallinan, G.; Beasley, A. J.

2018-04-01

As part of a wider search for radio emission from nearby systems known or suspected to contain extrasolar planets, ɛ Eridani was observed by the Jansky Very Large Array (VLA) in the 2–4 GHz and 4–8 GHz frequency bands. In addition, as part of a separate survey of thermal emission from solar-like stars, ɛ Eri was observed in the 8–12 GHz and the 12–18 GHz bands of the VLA. Quasi-steady continuum radio emission from ɛ Eri was detected in the three high-frequency bands at levels ranging from 67 to 83 μJy. No significant variability is seen in the quasi-steady emission. The emission in the 2–4 GHz emission, however, is shown to be the result of a circularly polarized (up to 50%) radio pulse or flare of a few minutes in duration that occurred at the beginning of the observation. We consider the astrometric position of the radio source in each frequency band relative to the expected position of the K2V star and the purported planet. The quasi-steady radio emission at frequencies ≥8 GHz is consistent with a stellar origin. The quality of the 4–8 GHz astrometry provides no meaningful constraint on the origin of the emission. The location of the 2–4 GHz radio pulse is >2.5σ from the star; however, based on the ephemeris of Benedict et al., it is not consistent with the expected location of the planet either. If the radio pulse has a planetary origin, then either the planetary ephemeris is incorrect or the emission originates from another planet.

Broad band simulation of Gamma Ray Bursts (GRB) prompt emission in presence of an external magnetic field

NASA Astrophysics Data System (ADS)

Ziaeepour, Houri; Gardner, Brian

2011-12-01

The origin of prompt emission in GRBs is not yet well understood. The simplest and most popular model is Synchrotron Self-Compton (SSC) emission produced by internal shocks inside an ultra-relativistic jet. However, recent observations of a delayed high energy component by the Fermi-LAT instrument have encouraged alternative models. Here we use a recently developed formulation of relativistic shocks for GRBs to simulate light curves and spectra of synchrotron and self-Compton emissions in the framework of internal shock model. This model takes into account the evolution of quantities such as densities of colliding shells, and fraction of kinetic energy transferred to electrons and to induced magnetic field. We also extend this formulation by considering the presence of a precessing external magnetic field. These simulations are very realistic and present significant improvement with respect to previous phenomenological GRB simulations. They reproduce light curves of separate peaks of real GRBs and variety of spectral slopes at E > Epeak observed by the Fermi-LAT instrument. The high energy emission can be explained by synchrotron emission and a subdominant contribution from inverse Compton. We also suggest an explanation for extended tail emission and relate it to the screening of the magnetic field and/or trapping of accelerated electrons in the electromagnetic energy structure of the plasma in the shock front. Spectral slopes of simulated bursts at E << Epeak are consistent with theoretical prediction and at E < Epeak can be flatter if the spectrum of electrons is roughly flat or has a shallow slope at low energies. The observed flat spectra at soft gamma-ray and hard x-ray bands is the evidence that there is a significant contribution at E < Epeak from lower Lorentz factor wing of electron distribution which have a roughly random acceleration rather than being thermal. This means that the state of matter in the jet at the time of ejection is most probably

Dimension yields from yellow-poplar lumber

Treesearch

R. C. Gilmore; J. D. Danielson

1984-01-01

The available supply of yellow poplar (Liriodendron tulipifera L.), its potential for new uses, and its continuing importance to the furniture industry have created a need to accumulate additional information about this species. As an aid to better utilization of this species, charts for determining cutting stock yields from yellow poplar lumber are presented for each...

The complete nucleotide sequence of the Barley yellow dwarf virus-RMV genome reveals it to be a new Polerovirus distantly related to other yellow dwarf viruses

USDA-ARS?s Scientific Manuscript database

The yellow dwarf viruses (YDVs) of the Luteoviridae family represent the most widespread group of cereal viruses worldwide. They include the Barley yellow dwarf viruses (BYDVs) of genus Luteovirus, the Cereal yellow dwarf viruses (CYDVs) and Wheat yellow dwarf virus (WYDV) of genus Polerovirus. All ...

7 CFR 28.441 - Strict Middling Yellow Stained Color.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Strict Middling Yellow Stained Color. 28.441 Section... Strict Middling Yellow Stained Color. Strict Middling Yellow Stained Color is color which is deeper than that of Strict Middling Tinged Color. [57 FR 34498, Aug. 5, 1992] ...

7 CFR 28.441 - Strict Middling Yellow Stained Color.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Strict Middling Yellow Stained Color. 28.441 Section... Strict Middling Yellow Stained Color. Strict Middling Yellow Stained Color is color which is deeper than that of Strict Middling Tinged Color. [57 FR 34498, Aug. 5, 1992] ...

7 CFR 28.441 - Strict Middling Yellow Stained Color.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Strict Middling Yellow Stained Color. 28.441 Section... Strict Middling Yellow Stained Color. Strict Middling Yellow Stained Color is color which is deeper than that of Strict Middling Tinged Color. [57 FR 34498, Aug. 5, 1992] ...

7 CFR 28.441 - Strict Middling Yellow Stained Color.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Strict Middling Yellow Stained Color. 28.441 Section... Strict Middling Yellow Stained Color. Strict Middling Yellow Stained Color is color which is deeper than that of Strict Middling Tinged Color. [57 FR 34498, Aug. 5, 1992] ...

7 CFR 28.441 - Strict Middling Yellow Stained Color.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Middling Yellow Stained Color. 28.441 Section... Strict Middling Yellow Stained Color. Strict Middling Yellow Stained Color is color which is deeper than that of Strict Middling Tinged Color. [57 FR 34498, Aug. 5, 1992] ...

Excitation of O+ Band EMIC Waves Through H+ Ring Velocity Distributions: Van Allen Probe Observations

NASA Astrophysics Data System (ADS)

Yu, Xiongdong; Yuan, Zhigang; Huang, Shiyong; Yao, Fei; Wang, Dedong; Funsten, Herbert O.; Wygant, John R.

2018-02-01

A typical case of electromagnetic ion cyclotron (EMIC) emissions with both He+ band and O+ band waves was observed by Van Allen Probe A on 14 July 2014. These emissions occurred in the morning sector on the equator inside the plasmasphere, in which region O+ band EMIC waves prefer to appear. Through property analysis of these emissions, it is found that the He+ band EMIC waves are linearly polarized and propagating quasi-parallelly along the background magnetic field, while the O+ band ones are of linear and left-hand polarization and propagating obliquely with respect to the background magnetic field. Using the in situ observations of plasma environment and particle data, excitation of these O+ band EMIC waves has been investigated with the linear growth theory. The calculated linear growth rate shows that these O+ band EMIC waves can be locally excited by ring current protons with ring velocity distributions. The comparison of the observed wave spectral intensity and the calculated growth rate suggests that the density of H+ rings providing the free energy for the instability has decreased after the wave grows. Therefore, this paper provides a direct observational evidence to the excitation mechanism of O+ band EMIC waves: ring current protons with ring distributions provide the free energy supporting the instability in the presence of rich O+ in the plasmasphere.

High-frequency tone-pip-evoked otoacoustic emissions in chinchillas

NASA Astrophysics Data System (ADS)

Siegel, Jonathan H.; Charaziak, Karolina K.

2015-12-01

We measured otoacoustic emissions in anesthetized chinchillas evoked by short (1 ms) high-frequency (4 kHz) tone-pips (TEOAE) using either a compression or suppression method to separate the stimulus from the emission. Both methods revealed consistent features of the TEOAEs. The main spectral band of the emission generally corresponded to the spectrum of the stimulus, exhibiting a group delay similar to that of SFOAEs [9]. However, a second spectral band below 1.5 kHz, clearly separated from the low-frequency cut-off frequency of the stimulus spectrum, corresponded to an amplitude modulation of the waveform of the TEOAE. The group delay of this low-frequency band was similar to that of the main band near the probe frequency. The average level and group delay of the main band declined monotonically when revealed as the suppressor frequency was raised above the probe. The low-frequency band was more sensitive than the main band to shifts in compound action potential thresholds near the probe frequency induced by acute exposure to intense tones. Taken together, the experiments indicate that both the main and low-frequency bands of the TEOAE are generated primarily near the cochlear region maximally stimulated by the probe, but that significant contributions arise over a large region even more basal.

Dual-emissive quantum dots for multispectral intraoperative fluorescence imaging.

PubMed

Chin, Patrick T K; Buckle, Tessa; Aguirre de Miguel, Arantxa; Meskers, Stefan C J; Janssen, René A J; van Leeuwen, Fijs W B

2010-09-01

Fluorescence molecular imaging is rapidly increasing its popularity in image guided surgery applications. To help develop its full surgical potential it remains a challenge to generate dual-emissive imaging agents that allow for combined visible assessment and sensitive camera based imaging. To this end, we now describe multispectral InP/ZnS quantum dots (QDs) that exhibit a bright visible green/yellow exciton emission combined with a long-lived far red defect emission. The intensity of the latter emission was enhanced by X-ray irradiation and allows for: 1) inverted QD density dependent defect emission intensity, showing improved efficacies at lower QD densities, and 2) detection without direct illumination and interference from autofluorescence. Copyright 2010 Elsevier Ltd. All rights reserved.

Thin-walled boron nitride microtubes exhibiting intense band-edge UV emission at room temperature.

PubMed

Huang, Yang; Bando, Yoshio; Tang, Chengchun; Zhi, Chunyi; Terao, Takeshi; Dierre, Benjamin; Sekiguchi, Takashi; Golberg, Dmitri

2009-02-25

Boron nitride (BN) microtubes were synthesized in a vertical induction furnace using Li(2)CO(3) and B reactants. Their structures and morphologies were investigated using x-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive x-ray spectroscopy. The microtubes have diameters of 1-3 microm, lengths of up to hundreds of micrometers, and well-structured ultrathin walls only approximately 50 nm thick. A mechanism combining the vapor-liquid-solid (VLS) and template self-sacrificing processes is proposed to explain the formation of these novel one-dimensional microstructures, in which the Li(2)O-B(2)O(3) eutectic reaction plays an important role. Cathodoluminescence studies show that even at room temperature the thin-walled BN microtubes can possess an intense band-edge emission at approximately 216.5 nm, which is distinct compared with other BN nanostructures. The study suggests that the thin-walled BN microtubes should be promising for constructing compact deep UV devices and find potential applications in microreactors and microfluidic and drug delivery systems.

Detection of boron nitride radicals by emission spectroscopy in a laser-induced plasma

NASA Astrophysics Data System (ADS)

Dutouquet, C.; Acquaviva, S.; Hermann, J.

2001-06-01

Several vibrational bands of boron nitride radicals have been observed in a plasma produced by pulsed-laser ablation of a boron nitride target in low-pressure nitrogen or argon atmospheres. Using time- and space-resolved emission spectroscopic measurements with a high dynamic range, the most abundant isotopic species B 11N have been detected. The emission bands in the spectral range from 340 to 380 nm belong to the Δυ =-1, 0, +1 sequences of the triplet system (transition A 3Π-X 3Π). For positive identification, the molecular emission bands have been compared with synthetic spectra obtained by computer simulations. Furthermore, B 10N emission bands have been reproduced by computer simulation using molecular constants which have been deduced from the B 11N constants. Nevertheless, the presence of the lower abundant isotopic radical B 10N was not proved due the noise level which masked the low emission intensity of the B 10N band heads.

THE TRANSMISSION OF YELLOW FEVER

PubMed Central

Davis, Nelson C.

1930-01-01

1. Saimiri sciureus has been infected with yellow fever virus, both by the inoculation of infectious blood and by the bites of infective mosquitoes. Some of the monkeys have died, showing lesions, including hepatic necrosis, suggesting yellow fever as seen in human beings and in rhesus monkeys. Virus has been transferred back to M. rhesus from infected Saimiri both by blood inoculation and by mosquito bites. The virus undoubtedly has been maintained through four direct passages in Saimiri. Reinoculations of infectious material into recovered monkeys have not given rise to invasion of the blood stream by virus. Sera from recovered animals have protected M. rhesus against the inoculation of virus. 2. It has been possible to pass the virus to and from Ateleus ater by the injection of blood or liver and by the bites of mosquitoes. The livers from two infected animals have shown no necrosis. The serum from one recovered monkey proved to be protective for M. rhesus. 3. Only three out of twelve Lagothrix lagotricha have reacted to yellow fever virus by a rise in temperature. Probably none have died as a result of the infection. In only one instance has the virus been transferred back to M. rhesus. The sera of recovered animals have had a protective action against yellow fever virus. PMID:19869721

High efficiency yellow organic light-emitting diodes with optimized barrier layers

NASA Astrophysics Data System (ADS)

Mu, Ye; Zhang, Shiming; Yue, Shouzhen; Wu, Qingyang; Zhao, Yi

2015-12-01

High efficiency Iridium (III) bis (4-phenylthieno [3,2-c] pyridinato-N,C2‧) acetylacetonate (PO-01) based yellow organic light-emitting devices are fabricated by employing multiple emission layers. The efficiency of the device using 4,4‧,4″-tris(N-carbazolyl) triphenylamine (TCTA) as potential barrier layer (PBL) outperforms those devices based on other PBLs and detailed analysis is carried out to reveal the mechanisms. A forward-viewing current efficiency (CE) of 65.21 cd/A, which corresponds to a maximum total CE of 110.85 cd/A is achieved at 335.8 cd/m2 in the optimized device without any outcoupling enhancement structures.

Increasing Mercury in Yellow Perch at a Hotspot in Atlantic Canada, Kejimkujik National Park

PubMed Central

2010-01-01

In the mid-1990s, yellow perch (Perca flavescens) and common loons (Gavia immer) from Kejimkujik National Park and National Historic Site (KNPNHS), Nova Scotia, Canada, had among the highest mercury (Hg) concentrations across North America. In 2006 and 2007, we re-examined 16 lakes to determine whether there have been changes in Hg in the loon’s preferred prey, yellow perch. Total Hg concentrations were measured in up to nine perch in each of three size classes (5−10 cm, 10−15 cm, and 15−20 cm) consumed by loons. Between 1996/97 and 2006/07, polynomial regressions indicated that Hg in yellow perch increased an average of 29% in ten lakes, decreased an average of 21% in three, and were unchanged in the remaining three lakes. In 2006/07, perch in 75% of the study lakes had Hg concentrations (standardized to 12-cm fish length) equal to or above the concentration (0.21 μg·g−1 ww) associated with a 50% reduction in maximum productivity of loons, compared with only 56% of these lakes in 1996/97. Mercury contamination currently poses a greater threat to loon health than a decade ago, and further reductions in anthropogenic emissions should be considered to reduce its impacts on ecosystem health. PMID:21062071

47 CFR 15.243 - Operation in the band 890-940 MHz.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation in the band 890-940 MHz. 15.243 Section 15.243 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.243 Operation in the band 890-940...

47 CFR 15.241 - Operation in the band 174-216 MHz.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation in the band 174-216 MHz. 15.241 Section 15.241 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.241 Operation in the band 174-216...

Yellow Fever Vaccine

MedlinePlus

... way to prevent yellow fever is to avoid mosquito bites by:staying in well-screened or air-conditioned areas, wearing clothes that cover most of your body, using an effective insect repellent, such as those containing DEET.

Acoustic emission frequency discrimination

NASA Technical Reports Server (NTRS)

Sugg, Frank E. (Inventor); Graham, Lloyd J. (Inventor)

1988-01-01

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.

Unpolarized emissivity with shadow and multiple reflections from random rough surfaces with the geometric optics approximation: application to Gaussian sea surfaces in the infrared band.

PubMed

Bourlier, Christophe

2006-08-20

The emissivity from a stationary random rough surface is derived by taking into account the multiple reflections and the shadowing effect. The model is applied to the ocean surface. The geometric optics approximation is assumed to be valid, which means that the rough surface is modeled as a collection of facets reflecting locally the light in the specular direction. In particular, the emissivity with zero, single, and double reflections are analytically calculated, and each contribution is studied numerically by considering a 1D sea surface observed in the near infrared band. The model is also compared with results computed from a Monte Carlo ray-tracing method.

Yellow fever cases in Asia: primed for an epidemic.

PubMed

Wasserman, Sean; Tambyah, Paul Anantharajah; Lim, Poh Lian

2016-07-01

There is currently an emerging outbreak of yellow fever in Angola. Cases in infected travellers have been reported in a number of other African countries, as well as in China, representing the first ever documented cases of yellow fever in Asia. There is a large Chinese workforce in Angola, many of whom may be unvaccinated, increasing the risk of ongoing importation of yellow fever into Asia via busy commercial airline routes. Large parts of the region are hyperendemic for the related Flavivirus dengue and are widely infested by Aedes aegypti, the primary mosquito vector of urban yellow fever transmission. The combination of sustained introduction of viraemic travellers, an ecology conducive to local transmission, and an unimmunized population raises the possibility of a yellow fever epidemic in Asia. This represents a major global health threat, particularly in the context of a depleted emergency vaccine stockpile and untested surveillance systems in the region. In this review, the potential for a yellow fever outbreak in Asia is discussed with reference to the ecological and historical forces that have shaped global yellow fever epidemiology. The limitations of surveillance and vector control in the region are highlighted, and priorities for outbreak preparedness and response are suggested. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Biology and biological control of Dalmatian and yellow toadflax

Treesearch

Sharlene E. Sing; Rosemarie De Clerck-Floate; Richard W. Hansen; Hal Pearce; Carol Bell Randall; Ivo Tosevski; Sarah M. Ward

2016-01-01

Dalmatian toadflax, Linaria dalmatica (L.) Mill., and yellow toadflax, Linaria vulgaris Mill., are exotic weeds of rangeland, grassland, forests, and cropland. Both Dalmatian and yellow toadflax are short-lived perennial forbs that are easily recognized by their yellow snapdragon- like flowers (Figure 1a, 1b). Both species propagate by seed and vegetatively...

White emission materials from glass doped with rare Earth ions: A review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yasaka, P.; Kaewkhao, J., E-mail: mink110@hotmail.com; Physics Program, Faculty of Science and Technology, Nakhon Pathom Rajabhat University, 73000

2016-03-11

Solid State Lighting (SSL) based devices are predicted to play a crucial role in the coming years. Development of W-LED, which have an edge over traditional lighting sources due to their compact size, higher reliability, shock resistance, interesting design possibilities, higher transparency and an extremely long lifetime. Over the fifteen trivalent lanthanide ions, Dy{sup 3+} ions doped glasses are most appropriate for white light generation because of the fact that it exhibits two intense emission bands corresponds to the {sup 4}F{sub 9/2}→{sup 6}H{sub 15/2} (magnetic dipole) and {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} (electric dipole) transitions at around 480-500 nm and 580-600 nmmore » pertaining to blue and yellow regions respectively. In this work, the developments of Dy3+ doped in several glass structures for white emitting materials application have reviewed. Properties of Dy{sup 3+} doped in glasses were discussed for use as a solid state lighting materials application.« less

33 CFR 117.225 - Yellow Mill Channel.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Yellow Mill Channel. 117.225 Section 117.225 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Connecticut § 117.225 Yellow Mill Channel. The...

Search for the OH (X(2)Pi) Meinel band emission in meteors as a tracer of mineral water in comets: detection of N(2)(+) (A-X)

NASA Technical Reports Server (NTRS)

Jenniskens, Peter; Laux, Christophe O.

2004-01-01

We report the discovery of the N(2)(+) A-X Meinel band in the 780-840 nm meteor emission from two Leonid meteoroids that were ejected less than 1000 years ago by comet 55P/Tempel-Tuttle. Our analysis indicates that the N(2)(+) molecule is at least an order of magnitude less abundant than expected, possibly as a result of charge transfer reactions with meteoric metal atoms. This new band was found while searching for rovibrational transitions in the X(2)Pi electronic ground state of OH (the OH Meinel band), a potential tracer of water bound to minerals in cometary matter. The electronic A-X transition of OH has been identified in other Leonid meteors. We did not detect this OH Meinel band, which implies that the excited A state is not populated by thermal excitation but by a mechanism that directly produces OH in low vibrational levels of the excited A(2)Sigma state. Ultraviolet dissociation of atmospheric or meteoric water vapor is such a mechanism, as is the possible combustion of meteoric organics.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2009-06-19

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 andmore » 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.« less

S-NPP VIIRS thermal emissive band gain correction during the blackbody warm-up-cool-down cycle

NASA Astrophysics Data System (ADS)

Choi, Taeyoung J.; Cao, Changyong; Weng, Fuzhong

2016-09-01

The Suomi National Polar orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) has onboard calibrators called blackbody (BB) and Space View (SV) for Thermal Emissive Band (TEB) radiometric calibration. In normal operation, the BB temperature is set to 292.5 K providing one radiance level. From the NOAA's Integrated Calibration and Validation System (ICVS) monitoring system, the TEB calibration factors (F-factors) have been trended and show very stable responses, however the BB Warm-Up-Cool-Down (WUCD) cycles provide detectors' gain and temperature dependent sensitivity measurements. Since the launch of S-NPP, the NOAA Sea Surface Temperature (SST) group noticed unexpected global SST anomalies during the WUCD cycles. In this study, the TEB Ffactors are calculated during the WUCD cycle on June 17th 2015. The TEB F-factors are analyzed by identifying the VIIRS On-Board Calibrator Intermediate Product (OBCIP) files to be Warm-Up or Cool-Down granules. To correct the SST anomaly, an F-factor correction parameter is calculated by the modified C1 (or b1) values which are derived from the linear portion of C1 coefficient during the WUCD. The F-factor correction factors are applied back to the original VIIRS SST bands showing significantly reducing the F-factor changes. Obvious improvements are observed in M12, M14 and M16, but corrections effects are hardly seen in M16. Further investigation is needed to find out the source of the F-factor oscillations during the WUCD.

The Mars diffuse aurora: A model of ultraviolet and visible emissions

NASA Astrophysics Data System (ADS)

Gérard, J.-C.; Soret, L.; Shematovich, V. I.; Bisikalo, D. V.; Bougher, S. W.

2017-05-01

A new type of Martian aurora, characterized by an extended spatial distribution, an altitude lower than the discrete aurora and electron precipitation up to 200 keV has been observed following solar activity on several occasions from the MAVEN spacecraft. We describe the results of Monte Carlo simulations of the production of several ultraviolet and violet auroral emissions for initial electron energies extending from 0.25 to 200 keV. These include the CO2+ ultraviolet doublet (UVD) at 288.3 and 289.6 nm and the Fox-Duffendack-Barker (FDB) bands, CO Cameron and Fourth Positive bands, OI 130.4 and 297.2 nm and CI 156.1 nm and 165.7 nm multiplets. We calculate the nadir and limb production rates of several of these emissions for a unit precipitated energy flux. Our results indicate that electrons in the range 50-200 keV produce maximum CO2+ UVD emission below 75 km, in agreement with the MAVEN observations. We calculate the efficiency of photon production per unit precipitated electron power. The strongest emissions are the CO2+ FDB, UVD and CO Cameron bands and the oxygen emission at 297.2 nm. The metastable a 3Π state which radiates the Cameron bands is deactivated by collisions below about 110 km. As a consequence, we show that the Cameron band emission is expected to peak at a higher altitude than the CO2+ UVD and FDB bands. Collisional quenching also causes the intensity ratio of the CO2+ UVD to CO Cameron bands to increase below ∼100 km in the energetic diffuse aurora.

False-color L-band image of Manaus region of Brazil

NASA Technical Reports Server (NTRS)

1994-01-01

This false-color L-band image of the Manaus region of Brazil was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperature Radar (SIR-C/X-SAR) flying on the Space Shuttle Endeavour on its 46th orbit. The area shown is approximately 8 kilometers by 40 kilometers (5 by 25 miles). At the top of the image are the Solimoes and Rio Negro River. The image is centered at about 3 degrees south latitude, and 61 degrees west longitude. Blue areas show low returns at VV poloarization; hence the bright blue colors of the smooth river surfaces. Green areas in the image are heavily forested, while blue areas are either cleared forest or open water. The yellow and red areas are flooded forest. Between Rio Solimoes and Rio Negro, a road can be seen running from some cleared areas (visible as blue rectangles north of Rio Solimoes) north toward a tributary or Rio Negro. The Jet Propulsion Laboratory alternative photo number is P-43895.

International travel between global urban centres vulnerable to yellow fever transmission.

PubMed

Brent, Shannon E; Watts, Alexander; Cetron, Martin; German, Matthew; Kraemer, Moritz Ug; Bogoch, Isaac I; Brady, Oliver J; Hay, Simon I; Creatore, Maria I; Khan, Kamran

2018-05-01

To examine the potential for international travel to spread yellow fever virus to cities around the world. We obtained data on the international flight itineraries of travellers who departed yellow fever-endemic areas of the world in 2016 for cities either where yellow fever was endemic or which were suitable for viral transmission. Using a global ecological model of dengue virus transmission, we predicted the suitability of cities in non-endemic areas for yellow fever transmission. We obtained information on national entry requirements for yellow fever vaccination at travellers' destination cities. In 2016, 45.2 million international air travellers departed from yellow fever-endemic areas of the world. Of 11.7 million travellers with destinations in 472 cities where yellow fever was not endemic but which were suitable for virus transmission, 7.7 million (65.7%) were not required to provide proof of vaccination upon arrival. Brazil, China, India, Mexico, Peru and the United States of America had the highest volumes of travellers arriving from yellow fever-endemic areas and the largest populations living in cities suitable for yellow fever transmission. Each year millions of travellers depart from yellow fever-endemic areas of the world for cities in non-endemic areas that appear suitable for viral transmission without having to provide proof of vaccination. Rapid global changes in human mobility and urbanization make it vital for countries to re-examine their vaccination policies and practices to prevent urban yellow fever epidemics.

Photon ratchet intermediate band solar cells

NASA Astrophysics Data System (ADS)

Yoshida, M.; Ekins-Daukes, N. J.; Farrell, D. J.; Phillips, C. C.

2012-06-01

In this paper, we propose an innovative concept for solar power conversion—the "photon ratchet" intermediate band solar cell (IBSC)—which may increase the photovoltaic energy conversion efficiency of IBSCs by increasing the lifetime of charge carriers in the intermediate state. The limiting efficiency calculation for this concept shows that the efficiency can be increased by introducing a fast thermal transition of carriers into a non-emissive state. At 1 sun, the introduction of a "ratchet band" results in an increase of efficiency from 46.8% to 48.5%, due to suppression of entropy generation.

Lost trust: a yellow fever patient response.

PubMed

Runge, John S

2013-12-13

In the 19th century, yellow fever thrived in the tropical, urban trade centers along the American Gulf Coast. Industrializing and populated, New Orleans and Memphis made excellent habitats for the yellow fever-carrying Aedes aegypti mosquitoes and the virulence they imparted on their victims. Known for its jaundice and black, blood-filled vomit, the malady terrorized the region for decades, sometimes claiming tens of thousands of lives during the near annual summertime outbreaks. In response to the failing medical community, a small, pronounced population of sick and healthy laypeople openly criticized the efforts to rid the Gulf region of yellow jack. Utilizing newspapers and cartoons to vocalize their opinions, these critics doubted and mocked the medical community, contributing to the regional and seasonal dilemma yellow fever posed for the American South. These sentient expressions prove to be an early example of patient distrust toward caregivers, a current problem in clinical heath care.

Lost Trust: A Yellow Fever Patient Response

PubMed Central

Runge, John S.

2013-01-01

In the 19th century, yellow fever thrived in the tropical, urban trade centers along the American Gulf Coast. Industrializing and populated, New Orleans and Memphis made excellent habitats for the yellow fever-carrying Aedes aegypti mosquitoes and the virulence they imparted on their victims. Known for its jaundice and black, blood-filled vomit, the malady terrorized the region for decades, sometimes claiming tens of thousands of lives during the near annual summertime outbreaks. In response to the failing medical community, a small, pronounced population of sick and healthy laypeople openly criticized the efforts to rid the Gulf region of yellow jack. Utilizing newspapers and cartoons to vocalize their opinions, these critics doubted and mocked the medical community, contributing to the regional and seasonal dilemma yellow fever posed for the American South. These sentient expressions prove to be an early example of patient distrust toward caregivers, a current problem in clinical heath care. PMID:24348220

21 CFR 137.290 - Self-rising yellow corn meal.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Self-rising yellow corn meal. 137.290 Section 137... Cereal Flours and Related Products § 137.290 Self-rising yellow corn meal. Self-rising yellow corn meal conforms to the definition and standard of identity prescribed by § 137.270 for self-rising white corn meal...

21 CFR 137.290 - Self-rising yellow corn meal.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Self-rising yellow corn meal. 137.290 Section 137... Cereal Flours and Related Products § 137.290 Self-rising yellow corn meal. Self-rising yellow corn meal conforms to the definition and standard of identity prescribed by § 137.270 for self-rising white corn meal...

Highly solid-state emissive pyridinium-substituted tetraphenylethylene salts: emission color-tuning with counter anions and application for optical waveguides.

PubMed

Hu, Fang; Zhang, Guanxin; Zhan, Chi; Zhang, Wei; Yan, Yongli; Zhao, Yongsheng; Fu, Hongbing; Zhang, Deqing

2015-03-18

In this paper seven salts of pyridinium-substituted tetraphenylethylene with different anions are reported. They show typical aggregation-induced emission. Crystal structures of three of the salts with (CF(3)SO(2))(2) N(-), CF(3) SO(3)(-), and SbF(6)(-) as the respective counter anions, are determined. The emission behavior of their amorphous and crystalline solids is investigated. Both amorphous and crystalline solids, except for the one with I(-), are highly emissive. Certain amorphous solids are red-emissive with almost the same quantum yields and fluorescence life-times. However, some crystalline solids are found to show different emission colors varying from green to yellow. Thus, their emission colors can be tuned by the counter anions. Furthermore, certain crystalline solids are highly emissive compared to the respective amorphous solids. Such solid-state emission behavior of these pyridinium-substituted tetraphenylethylene salts is interpreted on the basis of their crystal structures. In addition, optical waveguiding behavior of fabricated microrods is presented. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Competition between nonindigenous ruffe and native yellow perch in laboratory studies

USGS Publications Warehouse

Savino, Jacqueline F.; Kolar, Cynthia S.

1996-01-01

The ruffe Gymnocephalus cernuus is a European percid that was accidently introduced in Duluth Harbor, Lake Superior. This nonindigenous species is closely related to yellow perch Perca flavescens, and because the two species have similar diets and habitat requirements, they are potential competitors. Laboratory studies in aquaria and pools were conducted to determine whether ruffe can compete with yellow perch for food. Ruffe had capture rates similar to those of yellow perch when food was unlimited. Ruffe spent more time than yellow perch over a feeding container before leaving it and searching again, and they also required less time to ingest (or handle) prey. However, the presence of yellow perch shortened the time ruffe spent over foraging areas when food was more limited. In addition, yellow perch were more active than ruffe, as indicated by their more frequent visits to a feeding container. Hence, the outcome of exploitative competition was not conclusive; ruffe appear to have the advantage in some behaviors, yellow perch in others. Ruffe were much more aggressive than yellow perch, and interference competition may be important in the interactions between these species. Our results indicate that ruffe might compete with native yellow perch.

Influence of Background Genome on Enzymatic Characteristics of Yellow (Ay/-, Avy/-) Mice

PubMed Central

Wolff, George L.; Pitot, Henry C.

1973-01-01

Identification of the fundamental polypeptide difference between yellow (Ay/-, Avy/-) and non-yellow mice is important for biomedical research because of the influence of the yellow genotype on normal and neoplastic growth and obesity. The complexity of the "yellow mouse syndrome" makes attainment of this objective dependent on the separation of those pleiotropic enzyme differences which are secondary, and depend on the background genome, from those which are primary, and depend primarily on the agouti locus genotype.—Four of nine hepatic enzyme activities assayed simultaneously differed between eight-week-old yellow (Ay/-, Avy/-) and non-yellow (A/-, a/a) male inbred and F1 hybrid mice. Among these four, only cytoplasmic malic enzyme activity was elevated in all yellow mice, as compared with the non-yellow sibs, regardless of background genome. Glucokinase, serine dehydratase, and tyrosine α-ketoglutarate transaminase activities were also changed in yellow mice, but these alterations depended on the background genome.—The ratio of malic enzyme activity to citrate-cleavage enzyme activity, possibly related to the altered fat metabolism of yellow mice, was influenced by background genome as well as by the yellow genotype.——Significant deviations of enzyme activities from mid-parent values among F1 hybrids were associated with particular background genomes; the number of such deviations was larger among yellow mice than among non-yellows and this difference was greater among C3H F1 hybrids than among C57BL/6 F1 hybrids. PMID:4405752

Novel yellow-emitting Sr8MgLn(PO4)7:Eu2+ (Ln=Y, La) phosphors for applications in white LEDs with excellent color rendering index.

PubMed

Huang, Chien-Hao; Chen, Teng-Ming

2011-06-20

Eu(2+)-activated Sr(8)MgY(PO(4))(7) and Sr(8)MgLa(PO(4))(7) yellow-emitting phosphors were successfully synthesized by solid-state reactions for applications in excellent color rendering index white light-emitting diodes (LEDs). The excitation and reflectance spectra of these phosphors show broad band excitation and absorption in the 250-450 nm near-ultraviolet region, which is ascribed to the 4f(7) → 4f(6)5d(1) transitions of Eu(2+). Therefore, these phosphors meet the application requirements for near-UV LED chips. Upon excitation at 400 nm, the Sr(8)MgY(PO(4))(7):Eu(2+) and Sr(8)MgLa(PO(4))(7):Eu(2+) phosphors exhibit strong yellow emissions centered at 518, 610, and 611 nm with better thermal stability than (Ba,Sr)(2)SiO(4) (570 nm) commodity phosphors. The composition-optimized concentrations of Eu(2+) in Sr(8)MgLa(PO(4))(7):Eu(2+) and Sr(8)MgY(PO(4))(7):Eu(2+) phosphors were determined to be 0.01 and 0.03 mol, respectively. A warm white-light near-UV LED was fabricated using a near-UV 400 nm chip pumped by a phosphor blend of blue-emitting BaMgAl(10)O(17):Eu(2+) and yellow-emitting Sr(8)MgY(PO(4))(7):0.01Eu(2+) or Sr(8)MgLa(PO(4))(7):0.03Eu(2+), driven by a 350 mA current. The Sr(8)MgY(PO(4))(7):0.01Eu(2+) and Sr(8)MgLa(PO(4))(7):0.03Eu(2+) containing LEDs produced a white light with Commission International de I'Eclairage (CIE) chromaticity coordinates of (0.348, 0.357) and (0.365, 0.328), warm correlated color temperatures of 4705 and 4100 K, and excellent color rendering indices of 95.375 and 91.75, respectively. © 2011 American Chemical Society

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 109

NASA Technical Reports Server (NTRS)

Valdez, A.

2000-01-01

This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A1, S/N 109, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

47 CFR 22.359 - Emission limitations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... provided the measured power is integrated over the full required measurement bandwidth (i.e., 30 kHz or 1..., to the FCC. (d) Interference caused by out of band emissions. If any emission from a transmitter..., the FCC may require a greater attenuation of that emission than specified in this section. [70 FR...

Mechanism of radiative recombination in acceptor-doped bulk GaN crystals

NASA Astrophysics Data System (ADS)

Godlewski, M.; Suski, T.; Grzegory, I.; Porowski, S.; Bergman, J. P.; Chen, W. M.; Monemar, B.

1999-12-01

Optical and electrical properties of acceptor-doped bulk GaN crystals are discussed. Though introducing Zn and Ca to bulk GaN does not significantly change electron concentration, it results in the appearance of a blue photoluminescence band accompanying the relatively strong yellow band usually present. Highly resistive GaN : Mg crystals are obtained when high amount of Mg is introduced to the Ga melt during high-pressure synthesis. Change of electrical properties of Mg-doped bulk crystals is accompanied by the appearance of a strong blue emission of GaN similar to that in Ca- and Zn-doped crystals. Optically detected magnetic resonance investigations indicate a multi-band character of this blue emission and suggest possible mechanism of compensation in acceptor-doped bulk GaN.

Infrared radiation parameterizations for the minor CO2 bands and for several CFC bands in the window region

NASA Technical Reports Server (NTRS)

Kratz, David P.; Chou, Ming-Dah; Yan, Michael M.-H.

1993-01-01

Fast and accurate parameterizations have been developed for the transmission functions of the CO2 9.4- and 10.4-micron bands, as well as the CFC-11, CFC-12, and CFC-22 bands located in the 8-12-micron region. The parameterizations are based on line-by-line calculations of transmission functions for the CO2 bands and on high spectral resolution laboratory measurements of the absorption coefficients for the CFC bands. Also developed are the parameterizations for the H2O transmission functions for the corresponding spectral bands. Compared to the high-resolution calculations, fluxes at the tropopause computed with the parameterizations are accurate to within 10 percent when overlapping of gas absorptions within a band is taken into account. For individual gas absorption, the accuracy is of order 0-2 percent. The climatic effects of these trace gases have been studied using a zonally averaged multilayer energy balance model, which includes seasonal cycles and a simplified deep ocean. With the trace gas abundances taken to follow the Intergovernmental Panel on Climate Change Low Emissions 'B' scenario, the transient response of the surface temperature is simulated for the period 1900-2060.

International travel between global urban centres vulnerable to yellow fever transmission

PubMed Central

Brent, Shannon E; Watts, Alexander; Cetron, Martin; German, Matthew; Kraemer, Moritz UG; Bogoch, Isaac I; Brady, Oliver J; Hay, Simon I; Creatore, Maria I

2018-01-01

Abstract Objective To examine the potential for international travel to spread yellow fever virus to cities around the world. Methods We obtained data on the international flight itineraries of travellers who departed yellow fever-endemic areas of the world in 2016 for cities either where yellow fever was endemic or which were suitable for viral transmission. Using a global ecological model of dengue virus transmission, we predicted the suitability of cities in non-endemic areas for yellow fever transmission. We obtained information on national entry requirements for yellow fever vaccination at travellers’ destination cities. Findings In 2016, 45.2 million international air travellers departed from yellow fever-endemic areas of the world. Of 11.7 million travellers with destinations in 472 cities where yellow fever was not endemic but which were suitable for virus transmission, 7.7 million (65.7%) were not required to provide proof of vaccination upon arrival. Brazil, China, India, Mexico, Peru and the United States of America had the highest volumes of travellers arriving from yellow fever-endemic areas and the largest populations living in cities suitable for yellow fever transmission. Conclusion Each year millions of travellers depart from yellow fever-endemic areas of the world for cities in non-endemic areas that appear suitable for viral transmission without having to provide proof of vaccination. Rapid global changes in human mobility and urbanization make it vital for countries to re-examine their vaccination policies and practices to prevent urban yellow fever epidemics. PMID:29875519

YELLOW SUPERGIANTS IN THE ANDROMEDA GALAXY (M31)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drout, Maria R.; Massey, Philip; Meynet, Georges

2009-09-20

The yellow supergiant content of nearby galaxies can provide a critical test of stellar evolution theory, bridging the gap between the hot, massive stars and the cool red supergiants. But, this region of the color-magnitude diagram is dominated by foreground contamination, requiring membership to somehow be determined. Fortunately, the large negative systemic velocity of M31, coupled to its high rotation rate, provides the means for separating the contaminating foreground dwarfs from the bona fide yellow supergiants within M31. We obtained radial velocities of {approx}2900 individual targets within the correct color-magnitude range corresponding to masses of 12 M{sub sun} and higher.more » A comparison of these velocities to those expected from M31's rotation curve reveals 54 rank-1 (near certain) and 66 rank-2 (probable) yellow supergiant members, indicating a foreground contamination >= 96%. We expect some modest contamination from Milky Way halo giants among the remainder, particularly for the rank-2 candidates, and indeed follow-up spectroscopy of a small sample eliminates four rank 2's while confirming five others. We find excellent agreement between the location of yellow supergiants in the H-R diagram and that predicted by the latest Geneva evolutionary tracks that include rotation. However, the relative number of yellow supergiants seen as a function of mass varies from that predicted by the models by a factor of >10, in the sense that more high-mass yellow supergiants are predicted than those are actually observed. Comparing the total number (16) of >20 M{sub sun} yellow supergiants with the estimated number (24,800) of unevolved O stars indicates that the duration of the yellow supergiant phase is {approx}3000 years. This is consistent with what the 12 M{sub sun} and 15 M{sub sun} evolutionary tracks predict, but disagrees with the 20,000-80,000 year timescales predicted by the models for higher masses.« less

Manipulation of spontaneous emission in a tapered photonic crystal fibre

NASA Astrophysics Data System (ADS)

Myers, S. J.; Fussell, D. P.; Dawes, J. M.; Mägi, E.; McPhedran, R. C.; Eggleton, B. J.; de Sterke, C. Martijn

2006-12-01

We characterize the spontaneous emission of dye that is introduced into the central core of a tapered photonic crystal fiber. Since the photonic crystal period in the fibre cladding varies along the taper, the transmission and spontaneous emission spectra over a wide range of relative frequencies can be observed. The spontaneous emission spectra of the fibre transverse to the fiber axis show suppression due to partial band-gaps of the structure, and also enhancement of spontaneous emission near the band edges. We associate these with van Hove features, as well as finite cluster size effects.

Second Harmonic Hectometric Radio Emission at Jupiter

NASA Technical Reports Server (NTRS)

Menietti, J. D.; Gurnett, D. A.; Groene, J. B.

1998-01-01

Galileo has been in orbit around Jupiter since December 1995. The plasma wave instrument on board the spacecraft has occasionally detected a rotationally modulated attenuation band in the hectometric (HOM) emission that most likely is due to scattering of the radiation from density fluctuations along the Io L-shell, as reported earlier. The occurrence of the attenuation band is likely to be dependent on Io activity and the presence of density scattering centers along the Io-L-shell as well as the location of the source region. Some of the attenuation bands show clear indications of second harmonic emission. Without polarization measurements, it is difficult to place constraints on the local generation conditions based on the cyclotron maser instability, but the results imply that second harmonic emission could be present in the decametric (DAM) radiation as well. A survey of the data has revealed about 30 examples of second harmonic HOM.

Second Harmonic Hectometric Radio Emission at Jupiter

NASA Technical Reports Server (NTRS)

Menietti, J. D.; Gurnett, D. A.; Groene, J. B.

1998-01-01

Galileo has been in orbit around Jupiter since December 1995. The plasma wave instrument on board the spacecraft has occasionally detected a rotationally modulated attenuation band in the hectometric (HOM) emission that most likely is due to scattering of the radiation from density fluctuations along the Io L-shell, as reported earlier. The occurrence of the attenuation band is likely to be dependent on Io activity and the presence of density scattering centers along the Io L-shell as well as the location of the source region. Some of the attenuation bands show clear indications of second harmonic emission. Without polarization measurements, it is difficult to place constraints on the local generation conditions based on the cyclotron maser instability, but the results imply that second harmonic emission could be present in the decametric (DAM) radiation as well. A survey of the data has revealed about 30 examples of second harmonic HOM.

Introducing Eu{sup 2+} into yellow phosphor LiBaB{sub 9}O{sub 15}:Ce{sup 3+}, Dy{sup 3+} as blue emitting source to realize white emission

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Ting; Li, Panlai, E-mail: li_panlai@126.com; Fu, Nian, E-mail: funian3678@163.com

A series of Dy{sup 3+}, Ce{sup 3+}/Dy{sup 3+}, Eu{sup 2+}/Dy{sup 3+} and Ce{sup 3+}/Eu{sup 2+}/Dy{sup 3+} doping LiBaB{sub 9}O{sub 15} (LBB) phosphors were synthesized via a high temperature solid-state method. LBB:Dy{sup 3+} cannot create light under ultraviolet radiation, however, LBB:Ce{sup 3+}, Dy{sup 3+} can produce yellow emission under 295 nm excitation. The energy transfer occurs from Ce{sup 3+} to Dy{sup 3+} ions via electric dipole-dipole interaction and the critical distance is estimated to be 21.15 Å based on concentration quenching model. Generally, Eu{sup 2+} ion is a sensitizer to Dy{sup 3+} ion, however, there is only the emission of Eu{supmore » 2+} in LBB:Eu{sup 2+}, Dy{sup 3+}, which means there is no energy transfer from Eu{sup 2+} to Dy{sup 3+} ions. Interestingly enough, when doping Eu{sup 2+} ion into LBB:Ce{sup 3+}, Dy{sup 3+}, white emission can be achieved by increase the blue (350–425 nm) emission intensity. The spectral property, quantum efficiency, CIE chromaticity coordinates and thermal quenching property of LBB:Ce{sup 3+}, Eu{sup 2+}, Dy{sup 3+} are investigated. The results indicate that LBB:Ce{sup 3+}, Eu{sup 2+}, Dy{sup 3+} may be a potential application to white light emitting diodes. - Graphical abstract: LBB:Ce{sup 3+}, Dy{sup 3+} can create white emission by doping Eu{sup 2+} ions. - Highlights: • LBB:Ce{sup 3+}, Dy{sup 3+} can produce white emission by doping Eu{sup 2+} ion. • There is no energy transfer from Eu{sup 2+} to Dy{sup 3+} ions. • Energy transfer occurs from Ce{sup 3+} to Dy{sup 3+} ions. • LBB:Ce{sup 3+}, Eu{sup 2+}, Dy{sup 3+} may be a potential application for white LEDs.« less

The developing stages of the Martian yellow storm of 1971

NASA Technical Reports Server (NTRS)

Capen, C. F.; Martin, L. J.

1971-01-01

A history of the yellow storm on Mars which occurred in 1971 is presented. It is compared to the Great 1956 Yellow Cloud, and possible yellow storms are predicted for 1973. Photographs of the stages of evolution and the path of the storm are included.

Model Development for MODIS Thermal Band Electronic Crosstalk

NASA Technical Reports Server (NTRS)

Chang, Tiejun; Wu, Aisheng; Geng, Xu; Li, Yonghonh; Brinkman, Jake; Keller, Graziela; Xiong, Xiaoxiong

2016-01-01

MODerate-resolution Imaging Spectroradiometer (MODIS) has 36 bands. Among them, 16 thermal emissive bands covering a wavelength range from 3.8 to 14.4 m. After 16 years on-orbit operation, the electronic crosstalk of a few Terra MODIS thermal emissive bands developed substantial issues that cause biases in the EV brightness temperature measurements and surface feature contamination. The crosstalk effects on band 27 with center wavelength at 6.7 m and band 29 at 8.5 m increased significantly in recent years, affecting downstream products such as water vapor and cloud mask. The crosstalk effect is evident in the near-monthly scheduled lunar measurements, from which the crosstalk coefficients can be derived. The development of an alternative approach is very helpful for independent verification.In this work, a physical model was developed to assess the crosstalk impact on calibration as well as in Earth view brightness temperature retrieval. This model was applied to Terra MODIS band 29 empirically to correct the Earth brightness temperature measurements. In the model development, the detectors nonlinear response is considered. The impact of the electronic crosstalk is assessed in two steps. The first step consists of determining the impact on calibration using the on-board blackbody (BB). Due to the detectors nonlinear response and large background signal, both linear and nonlinear coefficients are affected by the crosstalk from sending bands. The second step is to calculate the effects on the Earth view brightness temperature retrieval. The effects include those from affected calibration coefficients and the contamination of Earth view measurements. This model links the measurement bias with crosstalk coefficients, detector non-linearity, and the ratio of Earth measurements between the sending and receiving bands. The correction of the electronic cross talk can be implemented empirically from the processed bias at different brightness temperature. The implementation

Caribbean yellow band disease compromises the activity of catalase and glutathione S-transferase in the reef-building coral Orbicella faveolata exposed to anthracene.

PubMed

Montilla, Luis Miguel; Ramos, Ruth; García, Elia; Cróquer, Aldo

2016-05-03

Healthy and diseased corals are threatened by different anthropogenic sources, such as pollution, a problem expected to become more severe in the near future. Despite the fact that coastal pollution and coral diseases might represent a serious threat to coral reef health, there is a paucity of controlled experiments showing whether the response of diseased and healthy corals to xenobiotics differs. In this study, we exposed healthy and Caribbean yellow band disease (CYBD)-affected Orbicella faveolata colonies to 3 sublethal concentrations of anthracene to test if enzymatic responses to this hydrocarbon were compromised in CYBD-affected tissues. For this, a 2-factorial fully orthogonal design was used in a controlled laboratory bioassay, using tissue condition (2 levels: apparently healthy and diseased) and pollutant concentration (4 levels: experimental control, 10, 30 and 100 ppb concentration) as fixed factors. A permutation-based ANOVA (PERMANOVA) was used to test the effects of condition and concentration on the specific activity of 3 enzymatic biomarkers: catalase, glutathione S-transferase, and glutathione peroxidase. We found a significant interaction between the concentration of anthracene and the colony condition for catalase (Pseudo-F = 3.84, df = 3, p < 0.05) and glutathione S-transferase (Pseudo-F = 3.29, df = 3, p < 0.05). Moreover, our results indicated that the enzymatic response to anthracene in CYBD-affected tissues was compromised, as the activity of these enzymes decreased 3- to 4-fold compared to healthy tissues. These results suggest that under a potential scenario of increasing hydrocarbon coastal pollution, colonies of O. faveolata affected with CYBD might become more vulnerable to the deleterious effects of chemical pollution.

PAH Emission in the Orion Bar

NASA Technical Reports Server (NTRS)

Bregman, Jesse; Sloan, G. C.

1996-01-01

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.

The 11.2 μm emission of PAHs in astrophysical objects

NASA Astrophysics Data System (ADS)

Candian, A.; Sarre, P. J.

2015-04-01

The 11.2-μm emission band belongs to the family of the `unidentified' infrared emission bands seen in many astronomical environments. In this work, we present a theoretical interpretation of the band characteristics and profile variation for a number of astrophysical sources in which the carriers are subject to a range of physical conditions. The results of Density Functional Theory calculations for the solo out-of-plane vibrational bending modes of large polycyclic aromatic hydrocarbon (PAH) molecules are used as input for a detailed emission model which includes the temperature and mass dependence of PAH band wavelength, and a PAH mass distribution that varies with object. Comparison of the model with astronomical spectra indicates that the 11.2-μm band asymmetry and profile variation can be explained principally in terms of the mass distribution of neutral PAHs with a small contribution from anharmonic effects.

Ceres' Yellow Spots - Observations with Dawn Framing Camera

NASA Astrophysics Data System (ADS)

Schäfer, Michael; Schäfer, Tanja; Cloutis, Edward A.; Izawa, Matthew R. M.; Platz, Thomas; Castillo-Rogez, Julie C.; Hoffmann, Martin; Thangjam, Guneshwar S.; Kneissl, Thomas; Nathues, Andreas; Mengel, Kurt; Williams, David A.; Kallisch, Jan; Ripken, Joachim; Russell, Christopher T.

2016-04-01

The Framing Camera (FC) onboard the Dawn spacecraft acquired several spectral data sets of (1) Ceres with increasing spatial resolution (up to 135 m/pixel with nearly global coverage). The FC is equipped with seven color filters (0.4-1.0 μm) plus one panchromatic ('clear') filter [1]. We produced spectral mosaics using photometrically corrected FC color filter images as described in [2]. Even early FC color mosaics obtained during Dawn's approach unexpectedly exhibited quite a diversity of surface materials on Ceres. Besides the ordinary cerean surface material, potentially composed of ammoniated phyllosilicates [3] or some other alteration product of carbonaceous chondrites [4], a large number of bright spots were found on Ceres [5]. These spots are substantially brighter than the average surface (exceeding its triple standard deviation), with the spots within Occator crater being the brightest and most prominent examples (reflectance more than 10 times the average of Ceres). We observed bright spots which are different by their obvious yellow color. This yellow color appears both in a 'true color' RGB display (R=0.65, G=0.55, B=0.44 μm) as well as in a false color display (R=0.97, G=0.75, B=0.44 μm) using a linear 2% stretch. Their spectra show a steep red slope between 0.44 and 0.55 μm (UV drop-off). On the contrary to these yellow spots, the vast majority of bright spots appears white in the aforementioned color displays and exhibit blue sloped spectra, except for a shallow UV drop-off. Thus, yellow spots are easily distinguishable from white spots and the remaining cerean surface by their high values in the ratio 0.55/0.44 μm. We found 8 occurrences of yellow spots on Ceres. Most of them (>70 individual spots) occur both inside and outside crater Dantu, where white spots are also found in the immediate vicinity. Besides Dantu, further occurrences with only a few yellow spots were found at craters Ikapati and Gaue. Less definite occurrences are found at 97

The evolution of adult light emission color in North American fireflies

PubMed Central

Hall, David W.; Sander, Sarah E.; Pallansch, Jennifer C.; Stanger-Hall, Kathrin F.

2016-01-01

Firefly species (Lampyridae) vary in the color of their adult bioluminescence. It has been hypothesized that color is selected to enhance detection by conspecifics. One mechanism to improve visibility of the signal is to increase contrast against ambient light. High contrast implies that fireflies active early in the evening will emit yellower luminescence to contrast against ambient light reflected from green vegetation, especially in habitats with high vegetation cover. Another mechanism to improve visibility is to use reflection off the background to enhance the light signal. Reflectance predicts that sedentary females will produce greener light to maximize reflection off the green vegetation on which they signal. To test these predictions, we recorded over 7500 light emission spectra and determined peak emission wavelength for 675 males, representing 24 species, at 57 field sites across the Eastern United States. We found support for both hypotheses: males active early in more vegetated habitats produced yellower flashes in comparison to later-active males with greener flashes. Further, in 2 of the 8 species with female data, female light emissions were significantly greener as compared to males. PMID:27412777

The evolution of adult light emission color in North American fireflies.

PubMed

Hall, David W; Sander, Sarah E; Pallansch, Jennifer C; Stanger-Hall, Kathrin F

2016-09-01

Firefly species (Lampyridae) vary in the color of their adult bioluminescence. It has been hypothesized that color is selected to enhance detection by conspecifics. One mechanism to improve visibility of the signal is to increase contrast against ambient light. High contrast implies that fireflies active early in the evening will emit yellower luminescence to contrast against ambient light reflected from green vegetation, especially in habitats with high vegetation cover. Another mechanism to improve visibility is to use reflection off the background to enhance the light signal. Reflectance predicts that sedentary females will produce greener light to maximize reflection off the green vegetation on which they signal. To test these predictions, we recorded over 7500 light emission spectra and determined peak emission wavelength for 675 males, representing 24 species, at 57 field sites across the Eastern United States. We found support for both hypotheses: males active early in more vegetated habitats produced yellower flashes in comparison to later-active males with greener flashes. Further, in two of the eight species with female data, female light emissions were significantly greener as compared to males. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Availability of yellow pine sawtimber in Alabama

Treesearch

William H. McWilliams

1991-01-01

Alabama's timberland supports 76.2 billion board feet of sawtimber (International 1/4-inch Rule), of which 55 percent is contributed by yellow pine species. Currently, yellow pine sawtimber volume totals 41.8 billion board feet. The recent inventory conducted by the USDA-Forest Service, Southern Forest Experiment Station, Forest Inventory and Analysis Unit (SO-...

Exciplex electroluminescence and photoluminescence spectra of the new organic materials based on zinc complexes of sulphanylamino-substituted ligands.

PubMed

Kaplunov, Mikhail G; Krasnikova, Svetlana S; Nikitenko, Sergey L; Sermakasheva, Natalia L; Yakushchenko, Igor K

2012-04-03

We have investigated the electroluminescence spectra of the electroluminescent devices based on the new zinc complexes of amino-substituted benzothiazoles and quinolines containing the C-N-M-N chains in their chelate cycles. The spectra exhibit strong exciplex bands in the green to yellow region 540 to 590 nm due to interaction of the excited states of zinc complexes and triaryl molecules of the hole-transporting layer. For some devices, the intrinsic luminescence band of 460 nm in the blue region is also observed along with the exciplex band giving rise to an almost white color of the device emission. The exciplex band can be eliminated if the material of the hole-transporting layer is not a triarylamine derivative. We have also found the exciplex emission in the photoluminescence spectra of the films containing blends of zinc complex and triphenylamine material.

Exciplex electroluminescence and photoluminescence spectra of the new organic materials based on zinc complexes of sulphanylamino-substituted ligands

PubMed Central

2012-01-01

We have investigated the electroluminescence spectra of the electroluminescent devices based on the new zinc complexes of amino-substituted benzothiazoles and quinolines containing the C-N-M-N chains in their chelate cycles. The spectra exhibit strong exciplex bands in the green to yellow region 540 to 590 nm due to interaction of the excited states of zinc complexes and triaryl molecules of the hole-transporting layer. For some devices, the intrinsic luminescence band of 460 nm in the blue region is also observed along with the exciplex band giving rise to an almost white color of the device emission. The exciplex band can be eliminated if the material of the hole-transporting layer is not a triarylamine derivative. We have also found the exciplex emission in the photoluminescence spectra of the films containing blends of zinc complex and triphenylamine material. PMID:22471942

47 CFR 90.669 - Emission limits.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Emission limits. 90.669 Section 90.669... 896-901/935-940 Mhz Band § 90.669 Emission limits. (a) On any frequency in an MTA licensee's spectrum block that is adjacent to a non-MTA frequency, the power of any emission shall be attenuated below the...

Using VISAR to assess the M-band isotropy in hohlraums

DOE PAGES

Lanier, Nicholas Edward; Kline, John L.; Morton, John

2016-09-27

In laser based radiation flow experiments, drive variability can often overwhelm the physics sensitivity that one seeks to quantify. Hohlraums can help by providing a more symmetrized, Planckian-like source. However, at higher temperatures, the hohlraum’s actual emission can deviate significantly from a truly blackbody, Lambertian source. At the National Ignition Facility (NIF), Dante provides the best quantification of hohlraum output. Unfortunately, limited diagnostic access coupled with NIF’s natural symmetry does not allow for Dante measurements at more than two angles. As part of the CEPHEUS campaign on NIF, proof-of-principle experiments to better quantify the gold M-band isotropy were conducted. Thesemore » experiments positioned beryllium/aluminum mirrors at differing angles, offset from the hohlraum. Filtering removes the thermal emission of the hohlraum and the remaining M-band radiation is preferentially absorbed in the aluminum layer. The subsequent hydrodynamic motion is measured via VISAR. Although indirect, this M-band measurement can be made at any angle.« less

A novel emaravirus is associated with redbud yellow ringspot disease

USDA-ARS?s Scientific Manuscript database

Yellow ringspot is the only virus-like disease reported in redbud (Cercis spp.) with symptoms including vein clearing, chlorotic ringspots and oak-leaf pattern. A putative new emaravirus was present in 48 of 48l trees displaying typical yellow ringspot symptoms and the name redbud yellow ringspot as...

47 CFR 15.223 - Operation in the band 1.705-10 MHz.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation in the band 1.705-10 MHz. 15.223 Section 15.223 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.223 Operation in the band 1.705-10...

Optimization of Replacing Pork Meat with Yellow Worm (Tenebrio molitor L.) for Frankfurters

PubMed Central

Paik, Hyun-Dong

2017-01-01

The effects of replacing pork meat with yellow mealworms on the physicochemical properties and sensory characteristics of frankfurters were investigated in this study. The control (50% pork ham), T1 (45% pork ham + 5% yellow mealworm), T2 (40% pork ham + 10% yellow mealworm), T3 (35% pork ham + 15% yellow mealworm), T4 (30% pork ham + 20% yellow mealworm), T5 (25% pork ham + 25% yellow mealworm), and T6 (20% pork ham + 30% yellow mealworm) were prepared, replacing lean pork meat with yellow mealworm. The moisture content, lightness, sarcoplasmic protein solubility, hardness, gumminess, chewiness, and apparent viscosity of frankfurters with yellow mealworm were lower than those of the control (p<0.05), whereas the content of protein and ash, pH, and yellowness of frankfurters with yellow mealworm were higher than those of the control (p<0.05). The fat content of frankfurters in T1 (p<0.05) was the highest, and the fat content of treatments decreased with increasing yellow mealworm concentrations (p<0.05). Frankfurters with increasing yellow mealworm concentrations had lower color, flavor, off-flavor, and juiciness scores. The overall acceptability was not significantly different in the control, T1, and T2 (p>0.05). Thus, the results of this study showed that replacing lean pork meat with up to 10% yellow mealworm successfully maintained the quality of frankfurters at a level similar to that of the regular control frankfurters. PMID:29147084

[The use of white and yellow turpentine baths with diabetic patients].

PubMed

Davydova, O B; Turova, E A; Golovach, A V

1998-01-01

In patients with insulin-dependent diabetes mellitus while and yellow turpentine baths produced a positive effect on carbohydrate metabolism. White baths were more effective in respect to lipid metabolism, blood viscosity, produced a good effect on plasmic hemocoagulation factors. Both while and yellow turpentine baths were beneficial for capillary blood flow: initially high distal blood flow in patients with prevailing distal polyneuropathy decreased while in patients with macroangiopathy initially subnormal blood flow increased. Both white and yellow turpentine baths promoted better pulse blood filling of the lower limbs and weaker peripheral resistance of large vessels. In patients with non-insulin-dependent diabetes mellitus white and yellow turpentine baths contributed to normalization of carbohydrate metabolism. Yellow baths were more effective in lowering lipids. White baths induced inhibition of platelet aggregation but had no effect on coagulation, yellow baths promoted a reduction of fibrinogen but had no effect on platelet aggregation. Yellow baths produced more pronounced effect than white ones on blood viscosity and microcirculation. Both yellow and white baths stimulated pulse blood filling, corrected peripheral resistance of large and small vessels of the lower limbs.

Mid infrared emission spectroscopy of carbon plasma.

PubMed

Nemes, Laszlo; Brown, Ei Ei; S-C Yang, Clayton; Hommerich, Uwe

2017-01-05

Mid infrared time-resolved emission spectra were recorded from laser-induced carbon plasma. These spectra constitute the first study of carbon materials LIB spectroscopy in the mid infrared range. The carbon plasma was induced using a Q-switched Nd: YAG laser. The laser beam was focused to high purity graphite pellets mounted on a translation stage. Mid infrared emission from the plasma in an atmospheric pressure background gas was detected by a cooled HgCdTe detector in the range 4.4-11.6μm, using long-pass filters. LIB spectra were taken in argon, helium and also in air. Despite a gate delay of 10μs was used there were strong backgrounds in the spectra. Superimposed on this background broad and noisy emission bands were observed, the form and position of which depended somewhat on the ambient gas. The spectra were digitally smoothed and background corrected. In argon, for instance, strong bands were observed around 4.8, 6.0 and 7.5μm. Using atomic spectral data by NIST it could be concluded that carbon, argon, helium and nitrogen lines from neutral and ionized atoms are very weak in this spectral region. The width of the infrared bands supports molecular origin. The infrared emission bands were thus compared to vibrational features of carbon molecules (excluding C2) of various sizes on the basis of previous carbon cluster infrared absorption and emission spectroscopic analyses in the literature and quantum chemical calculations. Some general considerations are given about the present results. Copyright © 2016 Elsevier B.V. All rights reserved.

Yellow Fever outbreaks in unvaccinated populations, Brazil, 2008-2009.

PubMed

Romano, Alessandro Pecego Martins; Costa, Zouraide Guerra Antunes; Ramos, Daniel Garkauskas; Andrade, Maria Auxiliadora; Jayme, Valéria de Sá; Almeida, Marco Antônio Barreto de; Vettorello, Kátia Campomar; Mascheretti, Melissa; Flannery, Brendan

2014-03-01

Due to the risk of severe vaccine-associated adverse events, yellow fever vaccination in Brazil is only recommended in areas considered at risk for disease. From September 2008 through June 2009, two outbreaks of yellow fever in previously unvaccinated populations resulted in 21 confirmed cases with 9 deaths (case-fatality, 43%) in the southern state of Rio Grande do Sul and 28 cases with 11 deaths (39%) in Sao Paulo state. Epizootic deaths of non-human primates were reported before and during the outbreak. Over 5.5 million doses of yellow fever vaccine were administered in the two most affected states. Vaccine-associated adverse events were associated with six deaths due to acute viscerotropic disease (0.8 deaths per million doses administered) and 45 cases of acute neurotropic disease (5.6 per million doses administered). Yellow fever vaccine recommendations were revised to include areas in Brazil previously not considered at risk for yellow fever.

Dengue-yellow fever sera cross-reactivity; challenges for diagnosis.

PubMed

Houghton-Triviño, Natalia; Montaña, Diana; Castellanos, Jaime

2008-01-01

The Flavivirus genera share epitopes inducing cross-reactive antibodies leading to great difficulty in differentially diagnosing flaviviral infections. This work was aimed at evaluating the complexity of dengue and yellow fever serological differential diagnosis. Dengue antibody capture ELISA and a yellow fever neutralisation test were carried out on 13 serum samples obtained from yellow fever patients, 20 acute serum samples from dengue patients and 19 voluntary serum samples pre- and post-vaccination with YF vaccine. Dengue ELISA revealed IgM reactivity in 46,2 % of yellow fever patients and 42 % of vaccinees. Sixteen out of 20 dengue patients (80 %) had high YF virus neutralisation titres. Such very high cross-reactivity data challenged differential laboratory diagnosis of dengue and yellow fever in areas where both flaviviruses co-circulate. New laboratory strategies are thus needed for improving the tests and providing a specific laboratory diagnosis. Cross-reactivity between Flaviviruses represents a great difficulty for epidemiological surveillance and preventing dengue, both of which demand urgent attention.

Interpreting the Subtle Spectral Variations of the 11.2 and 12.7 μm Polycyclic Aromatic Hydrocarbon Bands

NASA Astrophysics Data System (ADS)

Shannon, M. J.; Stock, D. J.; Peeters, E.

2016-06-01

We report new properties of the 11 and 12.7 μm emission complexes of polycyclic aromatic hydrocarbons (PAHs) by applying a Gaussian-based decomposition technique. Using high-resolution Spitzer Space Telescope data, we study in detail the spectral and spatial characteristics of the 11 and 12.7 μm emission bands in maps of reflection nebulae NGC 7023 and NGC 2023 (north and south) and the star-forming region M17. Profile variations are observed in both the 11 and 12.7 μm emission bands. We identify a neutral contribution to the traditional 11.0 μm PAH band and a cationic contribution to the traditional 11.2 μm band, the latter of which affects the PAH class of the 11.2 μm emission in our sample. The peak variations of the 12.7 μm complex are explained by the competition between two underlying blended components. The spatial distributions of these components link them to cations and neutrals. We conclude that the 12.7 μm emission originates in both neutral and cationic PAHs, lending support to the use of the 12.7/11.2 intensity ratio as a charge proxy.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A2, S/N 108, 08

NASA Technical Reports Server (NTRS)

Valdez, A.

2000-01-01

This is the Engineering Test Report, Radiated Emissions and SARR, SARP, DCS Receivers, Link Frequencies EMI Sensitive Band Test Results, AMSU-A2, S/N 108, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

Source apportionment of particulate pollutants in the atmosphere over the Northern Yellow Sea

NASA Astrophysics Data System (ADS)

Wang, L.; Qi, J. H.; Shi, J. H.; Chen, X. J.; Gao, H. W.

2013-05-01

Atmospheric aerosol samples were collected over the Northern Yellow Sea of China during the years of 2006 and 2007, in which the Total Carbon (TC), Cu, Pb, Cd, V, Zn, Fe, Al, Na+, Ca2+, Mg2+, NH4+, NO3-, SO42-, Cl-, and K+ were measured. The principle components analysis (PCA) and positive matrix factorization (PMF) receptor models were used to identify the sources of particulate matter. The results indicated that seven factors contributed to the atmospheric particles over the Northern Yellow Sea, i.e., two secondary aerosols (sulfate and nitrate), soil dust, biomass burning, oil combustion, sea salt, and metal smelting. When the whole database was considered, secondary aerosol formation contributed the most to the atmospheric particle content, followed by soil dust. Secondary aerosols and soil dust consisted of 65.65% of the total mass of particulate matter. The results also suggested that the aerosols over the North Yellow Sea were heavily influenced by ship emission over the local sea area and by continental agricultural activities in the northern China, indicating by high loading of V in oil combustion and high loading of K+ in biomass burning. However, the contribution of each factor varied greatly over the different seasons. In spring and autumn, soil dust and biomass burning were the dominant factors. In summer, heavy oil combustion contributed the most among these factors. In winter, secondary aerosols were major sources. Backward trajectories analysis indicated the 66% of air mass in summer was from the ocean, while the air mass is mainly from the continent in other seasons.

Structure and photoluminescence properties of ZnS-core/In2O3-shell one-dimensional nanowires

NASA Astrophysics Data System (ADS)

Park, Sunghoon; Lee, Jungkeun; Jeong, Bongyong; Lee, Wan In; Lee, Chongmu

2011-12-01

ZnS-core/In2O3-shell nanowires have been prepared by using a two-step process: the thermal evaporation of ZnS powders on Si(100) substrates coated with Au thin films and the sputter-deposition of In2O3. The ZnS nanowires were a few tens to a few hundreds of nanometers in diameter and up to a few hundreds of micrometers in length. ZnS nanowires have an emission band centered at around 570 nm in the yellow region. The yellow emission has been enhanced in intensity by coating the ZnS nanowires with In2O3 and further enhanced by annealing in a reducing atmosphere, but it is degraded by annealing in an oxidative atmosphere.

Contribution of the New WORLDVIEW-2 Spectral Bands for Urban Mapping in Coastal Areas: Case Study SÃO LUÍS ( MARANHÃO State, Brazil)

NASA Astrophysics Data System (ADS)

Souza, U. D. V.; kux, H. J. H.

2012-07-01

The objective of this study is to verify the contribution of the spectral bands from the new WorldView-2 satellite for the extraction of urban targets aiming a detailed mapping from the city of São Luis, at the coastal zone of Maranhão State, Brazil. This satellite system has 3 bands in the visible portion of the spectrum and also the following 4 new bands: Coastal (400-450 nm), Yellow (585- 625 nm), Red Edge (705-745 nm), and Near Infrared 2 (860-1040 nm). As for the methodology used, initially a fusion was made among the panchromatic and the multispectral bands, combining the spectral information of the multispectral bands with the geometric information of the panchromatic band. Following the ortho-rectification of the dataset was done, using ground control points (GCPs) obtained during field survey. The classification reached high values of Kappa indices. The use of the new bands Red Edge and Near Infrared 2, allowed the improvement of discriminations at tidal flats, mangrove and other vegetation types. The Yellow band improved the discrimination of bare soils - very important information for urban planning - and ceramic roofs. The Coastal band allowed to map the tidal channels which cross the urban area of São Luis, a typical feature of this coastal area. The functionalities of software GEODMA used, allowed an efficient attribute selection which improved the land cover classification from the test sites. The new WorldView-2 bands permit the identification and extraction of the features mentioned, because these bands are positioned at important parts of the electromagnetic spectrum, such as band Red Edge, which strongly improves the discrimination of vegetation conditions. Combining both higher spatial and spectral resolutions, WorldView-2 data allows an improvement on the discrimination of physical characteristics of the targets of interest, thus permitting a higher precision of land use/land cover maps, contributing to urban planning. The test sites of this

Discrete Electronic Bands in Semiconductors and Insulators: Potential High-Light-Yield Scintillators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Hongliang; Du, Mao-Hua

Bulk semiconductors and insulators typically have continuous valence and conduction bands. In this paper, we show that valence and conduction bands of a multinary semiconductor or insulator can be split to narrow discrete bands separated by large energy gaps. This unique electronic structure is demonstrated by first-principles calculations in several quaternary elpasolite compounds, i.e., Cs 2NaInBr 6, Cs 2NaBiCl 6, and Tl 2NaBiCl 6. The narrow discrete band structure in these quaternary elpasolites is due to the large electronegativity difference among cations and the large nearest-neighbor distances in cation sublattices. We further use Cs 2NaInBr 6 as an example tomore » show that the narrow bands can stabilize self-trapped and dopant-bound excitons (in which both the electron and the hole are strongly localized in static positions on adjacent sites) and promote strong exciton emission at room temperature. The discrete band structure should further suppress thermalization of hot carriers and may lead to enhanced impact ionization, which is usually considered inefficient in bulk semiconductors and insulators. Finally, these characteristics can enable efficient room-temperature light emission in low-gap scintillators and may overcome the light-yield bottleneck in current scintillator research.« less

Discrete Electronic Bands in Semiconductors and Insulators: Potential High-Light-Yield Scintillators

DOE PAGES

Shi, Hongliang; Du, Mao-Hua

2015-05-12

Bulk semiconductors and insulators typically have continuous valence and conduction bands. In this paper, we show that valence and conduction bands of a multinary semiconductor or insulator can be split to narrow discrete bands separated by large energy gaps. This unique electronic structure is demonstrated by first-principles calculations in several quaternary elpasolite compounds, i.e., Cs 2NaInBr 6, Cs 2NaBiCl 6, and Tl 2NaBiCl 6. The narrow discrete band structure in these quaternary elpasolites is due to the large electronegativity difference among cations and the large nearest-neighbor distances in cation sublattices. We further use Cs 2NaInBr 6 as an example tomore » show that the narrow bands can stabilize self-trapped and dopant-bound excitons (in which both the electron and the hole are strongly localized in static positions on adjacent sites) and promote strong exciton emission at room temperature. The discrete band structure should further suppress thermalization of hot carriers and may lead to enhanced impact ionization, which is usually considered inefficient in bulk semiconductors and insulators. Finally, these characteristics can enable efficient room-temperature light emission in low-gap scintillators and may overcome the light-yield bottleneck in current scintillator research.« less

Polycyclic Aromatic Hydrocarbon Emission in Spitzer /IRS Maps. II. A Direct Link between Band Profiles and the Radiation Field Strength

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stock, D. J.; Peeters, E., E-mail: dstock84@gmail.com

2017-03-10

We decompose the observed 7.7 μ m polycyclic aromatic hydrocarbon (PAH) emission complexes in a large sample of over 7000 mid-infrared spectra of the interstellar medium using spectral cubes observed with the Spitzer /IRS-SL instrument. In order to fit the 7.7 μ m PAH emission complex we invoke four Gaussian components, which are found to be very stable in terms of their peak positions and widths across all of our spectra, and subsequently define a decomposition with fixed parameters, which gives an acceptable fit for all the spectra. We see a strong environmental dependence on the interrelationships between our bandmore » fluxes—in the H ii regions all four components are intercorrelated, while in the reflection nebulae (RNs) the inner and outer pairs of bands correlate in the same manner as previously seen for NGC 2023. We show that this effect arises because the maps of RNs are dominated by emission from strongly irradiated photodissociation regions, while the much larger maps of H ii regions are dominated by emission from regions much more distant from the exciting stars, leading to subtly different spectral behavior. Further investigation of this dichotomy reveals that the ratio of two of these components (centered at 7.6 and 7.8 μ m) is linearly related to the UV-field intensity (log G {sub 0}). We find that this relationship does not hold for sources consisting of circumstellar material, which are known to have variable 7.7 μ m spectral profiles.« less

42 CFR 71.3 - Designation of yellow fever vaccination centers; Validation stamps.

Code of Federal Regulations, 2010 CFR

2010-10-01

... safe, potent, and pure yellow fever vaccine. Medical facilities of Federal agencies are authorized to obtain yellow fever vaccine without being designated as a yellow fever vaccination center by the Director..., storage, and administration of yellow fever vaccine. If a designated center fails to comply with such...

Genotyping points to divergent evolution of ‘Candidatus Phytoplasma asteris’ strains causing North American grapevine yellows and strains causing aster yellows

USDA-ARS?s Scientific Manuscript database

Grapevine yellows diseases occur in cultivated grapevine (Vitis vinifera L.) on several continents, where the diseases are known by different names depending upon the identities of the causal phytoplasmas. In this study, phytoplasma strains associated with grapevine yellows disease (North American ...

Yellow fever in China is still an imported disease.

PubMed

Chen, Jun; Lu, Hongzhou

2016-05-23

Yellow fever is a vector-borne disease endemic to tropical regions of Africa and South America. A recent outbreak in Angola caused hundreds of deaths. Six cases of yellow fever imported from Angola were reported recently in China. This raised the question of whether it will spread in China and how it can be prevented. This article discusses the possibility of yellow fever transmission in China and the strategies to counter it.

47 CFR 15.253 - Operation within the bands 46.7-46.9 GHz and 76.0-77.0 GHz.

Code of Federal Regulations, 2010 CFR

2010-10-01

...-77.0 GHz is restricted to vehicle-mounted field disturbance sensors used as vehicle radar systems... the radiating structure. (c) The power density of any emissions outside the operating band shall... GHz shall not exceed the general limits in § 15.209. (2) Radiated emissions outside the operating band...

Carriers of the mid-IR emission bands in PNe reanalysed. Evidence of a link between circumstellar and interstellar aromatic dust

NASA Astrophysics Data System (ADS)

Joblin, C.; Szczerba, R.; Berné, O.; Szyszka, C.

2008-10-01

Context: It has been shown that the diversity of the aromatic emission features can be rationalized into different classes of objects, in which differences between circumstellar and interstellar matter are emphasised. Aims: We probe the links between the mid-IR emitters observed in planetary nebulae (PNe) and their counterparts in the interstellar medium in order to probe a scenario in which the latter have been formed in the circumstellar environment of evolved stars. Methods: The mid-IR (6-14 μm) emission spectra of PNe and compact H II regions were analysed on the basis of previous work on photodissociation regions (PDRs). Galactic, Large Magellanic Cloud (LMC), and Small Magellanic Cloud (SMC) objects were considered in our sample. Results: We show that the mid-IR emission of PNe can be decomposed as the sum of six components. Some components made of polycyclic aromatic hydrocarbon (PAH) and very small grain (VSG) populations are similar to those observed in PDRs. Others are fitted in an evolutionary scenario involving the destruction of the aliphatic component observed in the post-AGB stage, as well as strong processing of PAHs in the extreme conditions of PNe that leads to a population of very large ionized PAHs. This species called PAHx are proposed as the carriers of a characteristic band at 7.90 μm. This band can be used as part of diagnostics that identify PNe in nearby galaxies and is also observed in galactic compact H II regions. Conclusions: These results support the formation of the aromatic very small dust particles in the envelopes of evolved stars, in the Milky Way, as well as in the LMC and SMC, and their subsequent survival in the interstellar medium. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the

Serologic assessment of yellow fever immunity in the rural population of a yellow fever-endemic area in Central Brazil.

PubMed

Machado, Vanessa Wolff; Vasconcelos, Pedro Fernando da Costa; Silva, Eliana Vieira Pinto; Santos, João Barberino

2013-01-01

The yellow fever epidemic that occurred in 1972/73 in Central Brazil surprised the majority of the population unprotected. A clinical-epidemiological survey conducted at that time in the rural area of 19 municipalities found that the highest (13.8%) number of disease cases were present in the municipality of Luziânia, State of Goiás. Thirty-eight years later, a new seroepidemiological survey was conducted with the aim of assessing the degree of immune protection of the rural population of Luziânia, following the continuous attempts of public health services to obtain vaccination coverage in the region. A total of 383 volunteers, aged between 5 and 89 years and with predominant rural labor activities (75.5%), were interviewed. The presence of antibodies against the yellow fever was also investigated in these individuals, by using plaque reduction neutralization test, and correlated to information regarding residency, occupation, epidemiological data and immunity against the yellow fever virus. We found a high (97.6%) frequency of protective titers (>1:10) of neutralizing antibodies against the yellow fever virus; the frequency of titers of 1:640 or higher was 23.2%, indicating wide immune protection against the disease in the study population. The presence of protective immunity was correlated to increasing age. This study reinforces the importance of surveys to address the immune state of a population at risk for yellow fever infection and to the surveillance of actions to control the disease in endemic areas.

Modeling the complexity of acoustic emission during intermittent plastic deformation: Power laws and multifractal spectra

NASA Astrophysics Data System (ADS)

Kumar, Jagadish; Ananthakrishna, G.

2018-01-01

Scale-invariant power-law distributions for acoustic emission signals are ubiquitous in several plastically deforming materials. However, power-law distributions for acoustic emission energies are reported in distinctly different plastically deforming situations such as hcp and fcc single and polycrystalline samples exhibiting smooth stress-strain curves and in dilute metallic alloys exhibiting discontinuous flow. This is surprising since the underlying dislocation mechanisms in these two types of deformations are very different. So far, there have been no models that predict the power-law statistics for discontinuous flow. Furthermore, the statistics of the acoustic emission signals in jerky flow is even more complex, requiring multifractal measures for a proper characterization. There has been no model that explains the complex statistics either. Here we address the problem of statistical characterization of the acoustic emission signals associated with the three types of the Portevin-Le Chatelier bands. Following our recently proposed general framework for calculating acoustic emission, we set up a wave equation for the elastic degrees of freedom with a plastic strain rate as a source term. The energy dissipated during acoustic emission is represented by the Rayleigh-dissipation function. Using the plastic strain rate obtained from the Ananthakrishna model for the Portevin-Le Chatelier effect, we compute the acoustic emission signals associated with the three Portevin-Le Chatelier bands and the Lüders-like band. The so-calculated acoustic emission signals are used for further statistical characterization. Our results show that the model predicts power-law statistics for all the acoustic emission signals associated with the three types of Portevin-Le Chatelier bands with the exponent values increasing with increasing strain rate. The calculated multifractal spectra corresponding to the acoustic emission signals associated with the three band types have a maximum

Modeling the complexity of acoustic emission during intermittent plastic deformation: Power laws and multifractal spectra.

PubMed

Kumar, Jagadish; Ananthakrishna, G

2018-01-01

Scale-invariant power-law distributions for acoustic emission signals are ubiquitous in several plastically deforming materials. However, power-law distributions for acoustic emission energies are reported in distinctly different plastically deforming situations such as hcp and fcc single and polycrystalline samples exhibiting smooth stress-strain curves and in dilute metallic alloys exhibiting discontinuous flow. This is surprising since the underlying dislocation mechanisms in these two types of deformations are very different. So far, there have been no models that predict the power-law statistics for discontinuous flow. Furthermore, the statistics of the acoustic emission signals in jerky flow is even more complex, requiring multifractal measures for a proper characterization. There has been no model that explains the complex statistics either. Here we address the problem of statistical characterization of the acoustic emission signals associated with the three types of the Portevin-Le Chatelier bands. Following our recently proposed general framework for calculating acoustic emission, we set up a wave equation for the elastic degrees of freedom with a plastic strain rate as a source term. The energy dissipated during acoustic emission is represented by the Rayleigh-dissipation function. Using the plastic strain rate obtained from the Ananthakrishna model for the Portevin-Le Chatelier effect, we compute the acoustic emission signals associated with the three Portevin-Le Chatelier bands and the Lüders-like band. The so-calculated acoustic emission signals are used for further statistical characterization. Our results show that the model predicts power-law statistics for all the acoustic emission signals associated with the three types of Portevin-Le Chatelier bands with the exponent values increasing with increasing strain rate. The calculated multifractal spectra corresponding to the acoustic emission signals associated with the three band types have a maximum

Present status of yellow fever: memorandum from a PAHO meeting.

PubMed

1986-01-01

An international seminar on the treatment and laboratory diagnosis of yellow fever, sponsored by the Pan American Health Organization (PAHO) and held in 1984, differed from previous meetings on yellow fever because of its emphasis on the care and management of patients and because the participants included specialists from several branches of medicine, such as hepatology, haematology, cardiology, infectious diseases, pathology and nephrology. The meeting reviewed the current status of yellow fever and problems associated with case-finding and notification; features of yellow fever in individual countries of Latin America; health services and facilities for medical care as they relate to diagnosis and management of cases; prevention strategies for and current status of immunization programmes; clinical and pathological aspects of yellow fever in humans; pathogenesis and pathophysiology of yellow fever in experimental animal models; clinical and specific laboratory diagnosis; treatment of the disease and of complications in the functioning of individual organ systems; prognosis and prognostic indicators; and directions for future clinical and experimental research on pathophysiology and treatment.

SU-F-J-46: Feasibility of Cerenkov Emission for Absorption Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oraiqat, I; Rehemtulla, A; Lam, K

2016-06-15

Purpose: Cerenkov emission (CE) is a promising tool for online tumor microenvironment interrogation and targeting during radiotherapy. In this work, we utilize CE generated during radiotherapy as a broadband excitation source for real-time absorption spectroscopy. We demonstrate the feasibility of CE spectroscopy using a controlled experiment of materials with known emission/absorption properties. Methods: A water tank is irradiated with 20 MeV electron beam to induce Cerenkov emission. Food coloring dyes (Yellow #5, Red #40, and Blue #1), which have known emission/absorption properties were added to the water tank with increasing concentration (1 drop (0.05 mL), 2 drops, and 4 dropsmore » from a dispenser bottle). The signal is collected using a condensing lens which is coupled into a 20m optical fiber that is fed into a spectrometer that measures the emitted spectra. The resulting spectra from water/food coloring dye solutions were normalized by the reference spectrum, which is the Cerenkov spectrum of pure water, correcting for both the nonlinearity of the broadband Cerenkov emission spectrum as well as the non-uniform spectral response of the spectrometer. The emitted spectra were then converted into absorbance and their characteristics were analyzed. Results: The food coloring dye had a drastic change on the Cerenkov emission, shifting its wavelength according to its visible color. The collected spectra showed various absorbance peaks which agrees with tabulated peak positions of the dyes added within 0.3% for yellow, 1.7% for red, and 0.16% for blue. The CE peak heights proportionally increased as the dye concentration is increased. Conclusion: This work shows the potential for real-time functional spectroscopy using Cerenkov emission during radiotherapy. It was demonstrated that molecule identification as well as relative concentration can be extracted from the Cerenkov emission color shift.« less

STUDIES ON SOUTH AMERICAN YELLOW FEVER

PubMed Central

Davis, Nelson C.; Shannon, Raymond C.

1929-01-01

Yellow fever virus from M. rhesus has been inoculated into a South American monkey (Cebus macrocephalus) by blood injection and by bites of infected mosquitoes. The Cebus does not develop the clinical or pathological signs of yellow fever. Nevertheless, the virus persists in the Cebus for a time as shown by the typical symptoms and lesions which develop when the susceptible M. rhesus is inoculated from a Cebus by direct transfer of blood or by mosquito (A. aegypti) transmission. PMID:19869607

Noise Characterization and Performance of MODIS Thermal Emissive Bands

NASA Technical Reports Server (NTRS)

Madhavan, Sriharsha; Xiong, Xiaoxiong; Wu, Aisheng; Wenny, Brian; Chiang, Kwofu; Chen, Na; Wang, Zhipeng; Li, Yonghong

2016-01-01

The MODerate-resolution Imaging Spectroradiometer (MODIS) is a premier Earth-observing sensor of the early 21st century, flying onboard the Terra (T) and Aqua (A) spacecraft. Both instruments far exceeded their six-year design life and continue to operate satisfactorily for more than 15 and 13 years, respectively. The MODIS instrument is designed to make observations at nearly a 100% duty cycle covering the entire Earth in less than two days. The MODIS sensor characteristics include a spectral coverage from 0.41micrometers to 14.4 micrometers, of which those wavelengths ranging from 3.7 micrometers to 14.4 micrometers cover the thermal infrared region which is interspaced in 16 thermal emissive bands (TEBs). Each of the TEB contains ten detectors which record samples at a spatial resolution of 1 km. In order to ensure a high level of accuracy for the TEB-measured top-of-atmosphere radiances, an onboard blackbody (BB) is used as the calibration source. This paper reports the noise characterization and performance of the TEB on various counts. First, the stability of the onboard BB is evaluated to understand the effectiveness of the calibration source. Next, key noise metrics such as the noise equivalent temperature difference and the noise equivalent dn difference (NEdN) for the various TEBs are determined from multiple temperature sources. These sources include the nominally controlled BB temperature of 290 K for T-MODIS and 285 K for A-MODIS, as well as a BB warm up-cool down cycle that is performed over a temperature range from roughly 270 to 315 K. The space-view port that measures the background signal serves as a viable cold temperature source for measuring noise. In addition, a well characterized Earth-view target, the Dome Concordia site located in the Antarctic plateau, is used for characterizing the stability of the sensor, indirectly providing a measure of the NEdN. Based on this rigorous characterization, a list of the noisy and inoperable detectors for

Maturation and Collection of Yellow-Poplar Seeds in the Midsouth

Treesearch

F. T. Bonner

1976-01-01

Yellow-poplar fruits are best collected in late October when their color changes from green to yellow-green or yellow. There were no other obvious physical or chemical changes indicating maturity. The seeds are physiologically mature as early as September 1, although high fruit moisture contents make special handling necessary if fruits are collected at this time....

Passive L-Band H Polarized Microwave Emission During the Corn Growth Cycle

NASA Astrophysics Data System (ADS)

Joseph, A. T.; van der Velde, R.; O'Neill, P. E.; Kim, E. J.; Lang, R. H.; Gish, T. J.

2012-12-01

Hourly L-band (1.4 GHz) horizontally (H) polarized brightness temperatures (TB's) measured during five episodes (more than two days of continuous measurements) of the 2002 corn growth cycle are analyzed. These TB 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 TB'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 TB. 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, hr, 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 TB 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 hr parameterization was responsible for the largest error reduction of TB simulations in the early growth cycle. A.T. Joseph, R. Van der Velde, P.E. O'Neill, R.H. Lang, and T. Gish, "Soil moisture retrieval during a corn growth cycle using L-band (1.6 GHz) radar observations", IEEE Transactions on Geoscience and Remote Sensing, vol. 46, DOI:10.1109/TGRS.2008.917214, Aug. 2008. M.C. Dobson, F.T. Ulaby, M

Auroral excitation of the N2 2P(0,0) and VK(0,9) bands

NASA Technical Reports Server (NTRS)

Solomon, Stanley C.

1989-01-01

The low-energy secondary electron flux caused by auroral electron precipitation is examined using data from the Atmosphere Explorer C satellite. An energetic electron transport algorithm is used to compute the differential electron flux produced by measured primaries. Emissions of N2 in the 2P(0,0) band at 337 nm and the VK(0,9) band at 335 nm predicted by the model are compared with photometric observation of their combined volume emission rate altitude profile made by the visible airglow experiment. Reasonable correspondence between model and measurement is obtained. Ratios of emissions at 337 nm and 630 nm to the N2(+) 1N(0,0) band at 428 nm are also studied. It is concluded that the 337/428 nm ratio responds to changes in the characteristic energy of primary auroral electrons only insofar as part of the 337 nm brightness is due to N2 VK(0,9) emission. The 630/428 nm ratio, which is strongly dependent on characteristic energy, also varies significantly with changes in atomic oxygen density.

Narrow-band filters for the lightning imager

NASA Astrophysics Data System (ADS)

Piegari, Angela; Di Sarcina, Ilaria; Grilli, Maria Luisa; Menchini, Francesca; Scaglione, Salvatore; Sytchkova, Anna; Zola, Danilo; Cuevas, Leticia P.

2017-11-01

The study of lightning phenomena will be carried out by a dedicated instrument, the lightning imager, that will make use of narrow-band transmission filters for separating the Oxygen emission lines in the clouds, from the background signal. The design, manufacturing and testing of these optical filters will be described here.

47 CFR 15.225 - Operation within the band 13.110-14.010 MHz.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation within the band 13.110-14.010 MHz. 15.225 Section 15.225 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.225 Operation within the band 13...

Variability of yellow tulp (Moraea pallida Bak.) toxicity.

PubMed

Snyman, L D; Schultz, R A; van den Berg, H

2011-06-01

Yellow tulp (Moraea pallida Bak.), collected predominantly during the flowering stage from a number of sites in South Africa, showed large variation in digoxin equivalent values, indicating variability in yellow tulp toxicity. Very low values were recorded for tulp collected from certain sites in the Northern Cape.

[Trends in yellow fever mortality in Colombia, 1998-2009].

PubMed

Segura, Ángela María; Cardona, Doris; Garzón, María Osley

2013-09-01

Yellow fever is a neglected tropical disease, thus, knowing the trends in mortality from this disease in Colombia is an important source of information for decision making and identifying public health interventions. To analyze trends in yellow fever mortality in Colombia during the 1998-2009 period and the differences in the morbidity and mortality information sources for the country, which affect indicators such as the lethality one. This is a descriptive study of deaths by yellow fever according to the Departamento Administrativo Nacional de Estadística and the incidence of the disease according to the Instituto Nacional de Salud . We used secondary sources of information in the calculation of proportions of socio-demographic characteristics of the deceased and epidemiological measures of lethality, incidence and mortality from yellow fever by department of residence of the deceased. Yellow fever deaths occur primarily in men of working age residing in scattered rural areas, who were members of the regimen vinculado, and who were living in the eastern, southeastern, northern and central zones in the country. We observed inconsistencies in the reports that affect the comparative analysis. The inhabitants of the departments located in national territories and Norte de Santander have an increased risk of illness and death from yellow fever, but this information could be underestimated, according to the source of information used for its calculation.

Rh-Catalyzed annulations of N-methoxybenzamides with ketenimines: synthesis of 3-aminoisoindolinones and 3-diarylmethyleneisoindolinones with strong aggregation induced emission properties.

PubMed

Zhou, Xiaorong; Peng, Zhixing; Zhao, Hongyang; Zhang, Zhiyin; Lu, Ping; Wang, Yanguang

2016-08-23

Rhodium-catalyzed C-H activation/annulation reactions of ketenimines with N-methoxybenzamides furnished 3-aminoisoindolin-1-ones and 3-(diarylmethylene)isoindolin-1-ones. The synthesized 3-(diarylmethylene)isoindolin-1-ones exhibited aggregation induced emissions in aqueous tetrahydrofuran solution and strong green-yellow emissions in solids.

47 CFR 90.1323 - Emission limits.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 5 2012-10-01 2012-10-01 false Emission limits. 90.1323 Section 90.1323 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Wireless Broadband Services in the 3650-3700 MHz Band § 90.1323 Emission limits. (a...

47 CFR 90.1323 - Emission limits.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Emission limits. 90.1323 Section 90.1323 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Wireless Broadband Services in the 3650-3700 MHz Band § 90.1323 Emission limits. (a...

Regulated emissions from biodiesel fuels from on/off-road applications

NASA Astrophysics Data System (ADS)

Durbin, Thomas D.; Cocker, David R.; Sawant, Aniket A.; Johnson, Kent; Miller, J. Wayne; Holden, Bruce B.; Helgeson, Norman L.; Jack, Jason A.

This research is one of the largest studies of biodiesel in both on-road and off-road uses. The testing was conducted for the military and encompassed a wide range of application types including two medium-duty trucks, two Humvees, a heavy heavy-duty diesel truck, a bus, two stationary backup generators (BUGs), a forklift, and an airport tow vehicle. The full range of fuels tested included a California ultra-low sulfur diesel (ULSD) fuel, different blend ratios of two different yellow-grease biodiesels and one soy-based biodiesel, JP-8, and yellow-grease biodiesel blends with two different NO x reduction additives. The B20-YGA, B20-YGB, and B20-Soy did not show trends relative to ULSD that were consistent over all applications tested. Higher biodiesel blends were tested on only one vehicle, but showed a tendency for higher total hydrocarbons (THC) and carbon monoxide (CO) emissions and lower particulate matter (PM) emissions. The JP-8 showed increases in THC and CO relative to the ULSD.

7 CFR 28.442 - Middling Yellow Stained Color.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Middling Yellow Stained Color. 28.442 Section 28.442... Stained Color. Middling Yellow Stained Color is American Upland cotton which in color is deeper than Middling Tinged Color. [57 FR 34498, Aug. 5, 1992] below color grade cotton ...

7 CFR 28.442 - Middling Yellow Stained Color.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Middling Yellow Stained Color. 28.442 Section 28.442... Stained Color. Middling Yellow Stained Color is American Upland cotton which in color is deeper than Middling Tinged Color. [57 FR 34498, Aug. 5, 1992] below color grade cotton ...

7 CFR 28.442 - Middling Yellow Stained Color.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Middling Yellow Stained Color. 28.442 Section 28.442... Stained Color. Middling Yellow Stained Color is American Upland cotton which in color is deeper than Middling Tinged Color. [57 FR 34498, Aug. 5, 1992] below color grade cotton ...

7 CFR 28.442 - Middling Yellow Stained Color.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Middling Yellow Stained Color. 28.442 Section 28.442... Stained Color. Middling Yellow Stained Color is American Upland cotton which in color is deeper than Middling Tinged Color. [57 FR 34498, Aug. 5, 1992] below color grade cotton ...

7 CFR 28.442 - Middling Yellow Stained Color.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Middling Yellow Stained Color. 28.442 Section 28.442... Stained Color. Middling Yellow Stained Color is American Upland cotton which in color is deeper than Middling Tinged Color. [57 FR 34498, Aug. 5, 1992] below color grade cotton ...

47 CFR 15.221 - Operation in the band 525-1705 kHz.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 1 2011-10-01 2011-10-01 false Operation in the band 525-1705 kHz. 15.221... kHz. (a) Carrier current systems and transmitters employing a leaky coaxial cable as the radiating antenna may operate in the band 525-1705 kHz provided the field strength levels of the radiated emissions...

47 CFR 15.221 - Operation in the band 525-1705 kHz.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation in the band 525-1705 kHz. 15.221... kHz. (a) Carrier current systems and transmitters employing a leaky coaxial cable as the radiating antenna may operate in the band 525-1705 kHz provided the field strength levels of the radiated emissions...

47 CFR 15.221 - Operation in the band 525-1705 kHz.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 1 2012-10-01 2012-10-01 false Operation in the band 525-1705 kHz. 15.221... kHz. (a) Carrier current systems and transmitters employing a leaky coaxial cable as the radiating antenna may operate in the band 525-1705 kHz provided the field strength levels of the radiated emissions...

47 CFR 15.221 - Operation in the band 525-1705 kHz.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 1 2014-10-01 2014-10-01 false Operation in the band 525-1705 kHz. 15.221... kHz. (a) Carrier current systems and transmitters employing a leaky coaxial cable as the radiating antenna may operate in the band 525-1705 kHz provided the field strength levels of the radiated emissions...

47 CFR 15.221 - Operation in the band 525-1705 kHz.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 1 2013-10-01 2013-10-01 false Operation in the band 525-1705 kHz. 15.221... kHz. (a) Carrier current systems and transmitters employing a leaky coaxial cable as the radiating antenna may operate in the band 525-1705 kHz provided the field strength levels of the radiated emissions...

47 CFR 15.229 - Operation within the band 40.66-40.70 MHz.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation within the band 40.66-40.70 MHz. 15.229 Section 15.229 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.229 Operation within the band 40.66...

47 CFR 15.227 - Operation within the band 26.96-27.28 MHz.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false Operation within the band 26.96-27.28 MHz. 15.227 Section 15.227 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Intentional Radiators Radiated Emission Limits, Additional Provisions § 15.227 Operation within the band 26.96...

INTERPRETING THE SUBTLE SPECTRAL VARIATIONS OF THE 11.2 AND 12.7 μ m POLYCYCLIC AROMATIC HYDROCARBON BANDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shannon, M. J.; Stock, D. J.; Peeters, E., E-mail: mshann3@uwo.ca

2016-06-20

We report new properties of the 11 and 12.7 μ m emission complexes of polycyclic aromatic hydrocarbons (PAHs) by applying a Gaussian-based decomposition technique. Using high-resolution Spitzer Space Telescope data, we study in detail the spectral and spatial characteristics of the 11 and 12.7 μ m emission bands in maps of reflection nebulae NGC 7023 and NGC 2023 (north and south) and the star-forming region M17. Profile variations are observed in both the 11 and 12.7 μ m emission bands. We identify a neutral contribution to the traditional 11.0 μ m PAH band and a cationic contribution to the traditionalmore » 11.2 μ m band, the latter of which affects the PAH class of the 11.2 μ m emission in our sample. The peak variations of the 12.7 μ m complex are explained by the competition between two underlying blended components. The spatial distributions of these components link them to cations and neutrals. We conclude that the 12.7 μ m emission originates in both neutral and cationic PAHs, lending support to the use of the 12.7/11.2 intensity ratio as a charge proxy.« less

Is it time for a new yellow fever vaccine?

PubMed

Hayes, Edward B

2010-11-29

An inexpensive live attenuated vaccine (the 17D vaccine) against yellow fever has been effectively used to prevent yellow fever for more than 70 years. Interest in developing new inactivated vaccines has been spurred by recognition of rare but serious, sometimes fatal adverse events following live virus vaccination. A safer inactivated yellow fever vaccine could be useful for vaccinating people at higher risk of adverse events from the live vaccine, but could also have broader global health utility by lowering the risk-benefit threshold for assuring high levels of yellow fever vaccine coverage. If ongoing trials demonstrate favorable immunogenicity and safety compared to the current vaccine, the practical global health utility of an inactivated vaccine is likely to be determined mostly by cost. Copyright © 2010 Elsevier Ltd. All rights reserved.

THE USE OF MICE IN TESTS OF IMMUNITY AGAINST YELLOW FEVER

PubMed Central

Sawyer, W. A.; Lloyd, Wray

1931-01-01

1. A method of testing sera for protective power against yellow fever is described and designated as the intraperitoneal protection test in mice. 2. The test consists essentially of the inoculation of mice intra-peritoneally with yellow fever virus, fixed for mice, together with the serum to be tested, and the simultaneous injection of starch solution into the brain to localize the virus. If the serum lacks protective power the mice die of yellow fever encephalitis. 3. The test is highly sensitive. Consequently it is useful in epidemiological studies to determine whether individuals have ever had yellow fever and in tests to find whether vaccinated persons or animals have in reality been immunized. 4. When mice were given large intraperitoneal injections of yellow fever virus fixed for mice, the virus could be recovered from the blood for 4 days although encephalitis did not occur. If the brain was mildly injured at the time of the intraperitoneal injection, the symptoms of yellow fever encephalitis appeared 6 days later, but the virus was then absent from the blood. 5. Strains of white mice vary greatly in their susceptibility to yellow fever. PMID:19869938

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kraiskii, A V; Mironova, T V; Sultanov, T T

2010-09-10

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)

Atmospheric correction using near-infrared bands for satellite ocean color data processing in the turbid western Pacific region.

PubMed

Wang, Menghua; Shi, Wei; Jiang, Lide

2012-01-16

A regional near-infrared (NIR) ocean normalized water-leaving radiance (nL(w)(λ)) model is proposed for atmospheric correction for ocean color data processing in the western Pacific region, including the Bohai Sea, Yellow Sea, and East China Sea. Our motivation for this work is to derive ocean color products in the highly turbid western Pacific region using the Geostationary Ocean Color Imager (GOCI) onboard South Korean Communication, Ocean, and Meteorological Satellite (COMS). GOCI has eight spectral bands from 412 to 865 nm but does not have shortwave infrared (SWIR) bands that are needed for satellite ocean color remote sensing in the turbid ocean region. Based on a regional empirical relationship between the NIR nL(w)(λ) and diffuse attenuation coefficient at 490 nm (K(d)(490)), which is derived from the long-term measurements with the Moderate-resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite, an iterative scheme with the NIR-based atmospheric correction algorithm has been developed. Results from MODIS-Aqua measurements show that ocean color products in the region derived from the new proposed NIR-corrected atmospheric correction algorithm match well with those from the SWIR atmospheric correction algorithm. Thus, the proposed new atmospheric correction method provides an alternative for ocean color data processing for GOCI (and other ocean color satellite sensors without SWIR bands) in the turbid ocean regions of the Bohai Sea, Yellow Sea, and East China Sea, although the SWIR-based atmospheric correction approach is still much preferred. The proposed atmospheric correction methodology can also be applied to other turbid coastal regions.

A Case of Yellow Fever Vaccine–Associated Viscerotropic Disease in Ecuador

PubMed Central

Douce, Richard W.; Freire, Diana; Tello, Betzabe; Vásquez, Gavino A.

2010-01-01

We report the first case of viscerotropic syndrome in Ecuador. Because of similarities between yellow fever and viscerotropic syndrome, the incidence of this recently described complication of vaccination with the 17D yellow fever vaccine is not known. There is a large population in South America that is considered at risk for possible reemergence of urban yellow fever. Knowledge of potentially fatal complications of yellow fever vaccine should temper decisions to vaccinate populations where the disease is not endemic. PMID:20348528

Thermal emission and absorption of radiation in finite inverted-opal photonic crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Florescu, Marian; Stimpson, Andrew J.; Lee, Hwang

We study theoretically the optical properties of a finite inverted-opal photonic crystal. The light-matter interaction is strongly affected by the presence of the three-dimensional photonic crystal and the alterations of the light emission and absorption processes can be used to suppress or enhance the thermal emissivity and absorptivity of the dielectric structure. We investigate the influence of the absorption present in the system on the relevant band edge frequencies that control the optical response of the photonic crystal. Our study reveals that the absorption processes cause spectral broadening and shifting of the band edge optical resonances, and determine a strongmore » reduction of the photonic band gap spectral range. Using the angular and spectral dependence of the band edge frequencies for stop bands along different directions, we argue that by matching the blackbody emission spectrum peak with a prescribed maximum of the absorption coefficient, it is possible to achieve an angle-sensitive enhancement of the thermal emission/absorption of radiation. This result opens a way to realize a frequency-sensitive and angle-sensitive photonic crystal absorbers/emitters.« less

Yellow River Delta, China

NASA Image and Video Library

2009-12-08

The Yellow River is the second-longest river in China, and the sixth longest in the world and makes many dramatic shifts over time. This image was taken with the ASTER instrument aboard NASA Terra spacecraft in 2009.

Yellow-Poplar Rooting Habits

Treesearch

John K. Francis

1979-01-01

Although the configuration of pole-sized yellow-poplar root systems in Tennessee is quite variable, a branched taproot with several widely spreading laterals is typical. Rooting depth is particularly limited by clayey texture, wetness, and firmness of subsoils.

Detect changes in lipid-related structure of brown- and yellow-seeded Brassica Carinata seed during rumen fermentation in relation to basic chemical profile using ATR-FT/IR molecular spectroscopy with chemometrics.

PubMed

Xin, Hangshu; Yu, Peiqiang

2014-12-10

In this experiment, brown- and yellow-seeded Brassica carinata were selected to use as a model to investigate whether there were any changes in lipid-related structure make-up (including CH3 and CH2 asymmetric and symmetric stretching bands ca. 3010-2765cm(-1), unsaturated lipid band ca. 3043-2987cm(-1) and carbonyl CO ester band ca. 1789-1701cm(-1)) of oilseed tissue during rumen in situ incubation using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FT/IR). Correlations of lipid spectral characteristics with basic chemical profile and multivariate analyses for clarifying structural differences within lipid regions between two carinata seeds were also measured. The results showed that most spectral parameters in both carinata seeds were reduced as incubation time increased. However, the extent of changes in peak intensity of carbonyl CO ester group of brown-seeded carinata was not in fully accordance with that of yellow-seeded carinata. Additionally, these lipid structure features were highly correlated with the concentrations of OM (positively), CP (positively), NDF (negatively) and EE (positively) in carinata seeds after 0, 12, 24 and 48h of incubation. Based on the results from multivariate analyses, neither AHCA nor PCA could produce any distinctions in rumen residues between brown- and yellow-seeded carinata in spectra at lipid regions. It was concluded that besides for original feed samples, spectroscopic technique of ATR-FT/IR could also be used for rumen degradation residues in detecting changes in lipid-related molecular structure make-up. Further studies are needed to explore more details in lipid metabolism during ruminal fermentation with the combined consideration on both metabolic basis and molecular structural basis. Copyright © 2014 Elsevier B.V. All rights reserved.

Seasonal differences in freezing tolerance of yellow-cedar and western hemlock trees at a site affected by yellow-cedar decline

Treesearch

Paul G. Schaberg; Paul E. Hennon; Amore, David V. D; Gary J. Hawley; Catherine H. Borer; Catherine H. Borer

2005-01-01

To assess whether inadequate cold hardiness could be a contributor to yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach) decline, we measured the freezing tolerance of foliage from yellow-cedar trees in closed-canopy (nondeclining) and open-canopy (declining at elevations below 130 m) stands at three sites along an elevational gradient in the heart of the decline...

Excitation of the Werner bands of H2 by electron impact

NASA Technical Reports Server (NTRS)

Stone, E. J.; Zipf, E. C.

1972-01-01

Absolute cross sections for the excitation of the H2 Werner band system were measured from energy threshold to 300 eV for electron impact on H2. The bands were observed in emission in the wavelength region 1100A to 1250A. The measured cross sections were compared with published transition probabilities, leading to the conclusion that the Werner bands are suitable as the basis for a relative spectral response calibration only when the bands are observed under sufficiently high resolution. The effect of the perturbation between the C 1Pi u and B 1 Sigma-u states of the hydrogen molecule was clearly observed in anomalies in the rotational intensity distribution in bands of the (3 v '') progression.

Introducing the yellow laser

NASA Astrophysics Data System (ADS)

Lincoln, James

2018-02-01

The author has acquired a yellow laser with the specific wavelength of 589 nm. Because this is the first time such a laser has been discussed in this journal, I feel it is appropriate to provide a discussion of its function and capabilities. Normal laser safety should be employed, such as not pointing it into eyes or at people, and using eye protection for the young and inexperienced. It is important to note that 589 nm is the same wavelength as the Sodium-D line (doublet). This allows for the laser to serve as a replacement for sodium lamps, and, considering its rather high price, this added value should be balanced against its cost. What follows is a list of activities that showcase the yellow laser's unique promise as an engaging piece of technology that can be used in the teaching of physics.

Silvical characteristics of yellow birch (Betula alleghaniensis)

Treesearch

Adrian M. Gilbert

1960-01-01

Of the birches in the Northeast, the yellow birch is the elite species, by far the most valuable as a timber tree. More than that, it is one of the largest deciduous trees of northeastern America. It may reach 100 feet in height and more than 3 feet in diameter, and may live to 300 years of age. Pioneers told tales of the gigantic yellow birches they saw.

Growth and band gap of the filled tetrahedral semiconductor LiMgN

NASA Astrophysics Data System (ADS)

Kuriyama, K.; Nagasawa, K.; Kushida, K.

2002-04-01

The cubic AlN-like compound, LiMgN, can be considered as a zinc blende-like (MgN) - lattice partially filled with He-like Li + interstitials. LiMgN was synthesized by direct reaction between N 2 and LiMg alloy at around 800°C for 8 h. Polycrystalline crystals are grown as cornflake-like shapes with a light yellow color and show the LiMgN-phase (the lattice constant a=4.955±0.005 Å) except for non-reactant LiMg and oxide (LiNO 3). The ordered structure between Li and Mg is not confirmed exactly by X-ray diffraction studies. The band gap of as-grown crystals evaluated using photoacoustic spectroscopy is 3.2 eV, which value is supported by an optical transmission spectrum. The band gap value of LiMgN is close to that of GaN (zinc blende, Eg=3.45 eV).

Travelers' Health: Yellow Fever

MedlinePlus

... and local rate of virus transmission at the time of travel. Although reported cases of human disease are the ... be receiving yellow fever vaccine for the first time. If travel is unavoidable, the decision to vaccinate travelers aged ≥ ...

[The fourth horseman: The yellow fever].

PubMed

Vallejos-Parás, Alfonso; Cabrera-Gaytán, David Alejandro

2017-01-01

Dengue virus three, Chikunguya and Zika have entered the national territory through the south of the country. Cases and outbreaks of yellow fever have now been identified in the Americas where it threatens to expand. Although Mexico has a robust epidemiological surveillance system for vector-borne diseases, our country must be alert in case of its possible introduction into the national territory. This paper presents theoretical assumptions based on factual data on the behavior of yellow fever in the Americas, as well as reflections on the epidemiological surveillance of vector-borne diseases.

Yellow fever: a reemerging threat.

PubMed

Gardner, Christina L; Ryman, Kate D

2010-03-01

Yellow fever (YF) is a viral disease, endemic to tropical regions of Africa and the Americas, which principally affects humans and nonhuman primates and is transmitted via the bite of infected mosquitoes. Yellow fever virus (YFV) can cause devastating epidemics of potentially fatal, hemorrhagic disease. Despite mass vaccination campaigns to prevent and control these outbreaks, the risk of major YF epidemics, especially in densely populated, poor urban settings, both in Africa and South America, has greatly increased. Consequently, YF is considered an emerging, or reemerging disease of considerable importance. This article comprehensively reviews the history, microbiology, epidemiology, clinical presentation, diagnosis, and treatment of YFV, as well as the vaccines produced to combat YF. 2010 Elsevier Inc. All rights reserved.

Cucumber vein yellowing virus

USDA-ARS?s Scientific Manuscript database

Cucurbits are an important crop of temperate, subtropical and tropical regions of the world. Cucumber vein yellowing virus (CVYV) is a major viral pathogen of cucurbits. This chapter provides an overview of the biology of CVYV and the disease it causes....

Yellowing and bleaching of grey hair caused by photo and thermal degradation.