WorldWideScience

Sample records for primary emission wavelength

  1. Emission wavelength of multilayer distributed feedback dye lasers

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Smith, Cameron L. C.; Brøkner Christiansen, Mads

    2012-01-01

    Precise emission wavelength modeling is essential for understanding and optimization of distributed feedback (DFB) lasers. An analytical approach for determining the emission wavelength based on setting the propagation constant of the Bragg condition and solving for the resulting slab waveguide m...

  2. Study of the correlation of scintillation decay and emission wavelength

    International Nuclear Information System (INIS)

    Yanagida, Takayuki; Fujimoto, Yutaka; Yamaji, Akihiro; Kawaguchi, Noriaki; Kamada, Kei; Totsuka, Daisuke; Fukuda, Kentaro; Yamanoi, Kohei; Nishi, Ryosuke; Kurosawa, Shunsuke; Shimizu, Toshihiko; Sarukura, Nobuhiko

    2013-01-01

    In photoluminescence which directly excites the emission center of phosphor material is known to have a correlation between the emission wavelength and the decay time based on quantum mechanics. In scintillation phenomenon, host lattice of the material is first excited by ionizing radiation and then the excitation energy is transferred to emission centers. For the first time, we investigated the correlation between the scintillation decay and the emission wavelength by using pulse X-ray equipped streak camera system which could observe time and wavelength resolved scintillation phenomenon. Investigated materials were Ce 3+ , Pr 3+ and Nd 3+ doped oxides and fluorides which all showed 5d-4f transition based emission. As a result, we obtained the relation that τ (scintillation decay time) was proportional to the λ 2.15 (emission wavelength). -- Highlights: ► The correlation between emission wavelength and scintillation decay time is investigated. ► Photoluminescence decay times are also evaluated and compared with scintillation decay times. ► It is proved the relaxation process in emission center is dominant even in scintillation decay

  3. Self-amplified spontaneous emission for short wavelength coherent radiation

    International Nuclear Information System (INIS)

    Kim, K.J.; Xie, M.

    1992-09-01

    We review the recent progress in our understanding of the self-amplified spontaneous emission (SASE), emphasizing the application to short wavelength generation. Simple formulae are given for the start-up, exponential gain and the saturation of SASE. Accelerator technologies producing high brightness electron beams required for short wavelength SASE are discussed. An example utilizing electron beams from a photocathode-linac system to produce 4nm SASE in the multigigawatt range is presented

  4. Enhanced Plasmonic Wavelength Selective Infrared Emission Combined with Microheater

    Directory of Open Access Journals (Sweden)

    Hiroki Ishihara

    2017-09-01

    Full Text Available The indirect wavelength selective thermal emitter that we have proposed is constructed using a new microheater, demonstrating the enhancement of the emission peak generated by the surface plasmon polariton. The thermal isolation is improved using a 2 μm-thick Si membrane having 3.6 and 5.4 mm outer diameter. The emission at around the wavelength of the absorption band of CO2 gas is enhanced. The absorption signal increases, confirming the suitability for gas sensing. Against input power, the intensity at the peak wavelength shows a steeper increasing ratio than the background intensity. The microheater with higher thermal isolation gives larger peak intensity and its increasing ratio against the input power.

  5. Digitally tunable dual wavelength emission from semiconductor ring lasers with filtered optical feedback

    International Nuclear Information System (INIS)

    Khoder, Mulham; Verschaffelt, Guy; Nguimdo, Romain Modeste; Danckaert, Jan; Leijtens, Xaveer; Bolk, Jeroen

    2013-01-01

    We report on a novel integrated approach to obtain dual wavelength emission from a semiconductor laser based on on-chip filtered optical feedback. Using this approach, we show experiments and numerical simulations of dual wavelength emission of a semiconductor ring laser. The filtered optical feedback is realized on-chip by employing two arrayed waveguide gratings to split/recombine light into different wavelength channels. Semiconductor optical amplifiers are placed in the feedback loop in order to control the feedback strength of each wavelength channel independently. By tuning the current injected into each of the amplifiers, we can effectively cancel the gain difference between the wavelength channels due to fabrication and material dichroism, thus resulting in stable dual wavelength emission. We also explore the accuracy needed in the operational parameters to maintain this dual wavelength emission. (letter)

  6. Controlling the emission wavelength in group III-V semiconductor laser diodes

    KAUST Repository

    Ooi, Boon S.; Majid, Mohammed Abdul; Afandy, Rami; Aljabr, Ahmad

    2016-01-01

    Methods are provided for modifying the emission wavelength of a semiconductor quantum well laser diode, e.g. by blue shifting the emission wavelength. The methods can be applied to a variety of semiconductor quantum well laser diodes, e.g. group III

  7. Prediction of Backscatter and Emissivity of Snow at Millimeter Wavelengths.

    Science.gov (United States)

    1980-01-01

    AD-AI16 9A MASSACHUISETTS IMST OF TECH CAMBRIDGE RESEARCH LAB OF-ETC F/6 17/9 PREDICTION OF BACKSCATTER AND EMISSIVITY OF SNOW AT MILLETER --ETC(U...emitting media such as snow. The emissivity in the Ray- leigh- Jeans approximation is then the microwave brightness tempera- ture T divided by an effective...resistivity, and thermal tempera- ture. Jean et al. (Reference 125) compared a theoretical expression for the total apparent temperature of a smooth surface

  8. Sensitivity of Heterointerfaces on Emission Wavelength in Quantum Cascade Lasers

    Science.gov (United States)

    2016-10-31

    thickness. To correct the composition, a secondary flow of the Al precursor was added during MOVPE growth to increase Al content in QCLs. The resulting...diluted 200 ppm in H2) was used as the n-type dopant. The growth temperature was 625 °C as measured by emissivity corrected optical pyrometrey. AlInAs and...Muraki, S. Fukatsu, Y. Shiraki, and R. Ito , "Surface segregation of In atoms during molecular beam epitaxy and its influence on the energy levels in

  9. Continuously tunable sub-half-wavelength localization via coherent control of spontaneous emission

    International Nuclear Information System (INIS)

    Wang Fei; Tan Xin-Yu; Gong Cheng; Shi Wen-Xing

    2012-01-01

    We propose a continuously tunable method of sub-half-wavelength localization via the coherent control of the spontaneous emission of a four-level Y-type atomic system, which is coupled to three strong coupling fields including a standing-wave field together with a weak probe field. It is shown that the sub-half-wavelength atomic localization is realized for both resonance and off-resonance cases. Furthermore, by varying the probe detuning in succession, the positions of the two localization peaks are tuned continuously within a wide range of probe field frequencies, which provides convenience for the realization of sub-half-wavelength atomic localization experimentally

  10. [Investigation of multi-wavelength effect during the measurement of UV-enhanced film's emission spectrum].

    Science.gov (United States)

    Liu, Meng; Ni, Zheng-ji; Zhang, Da-wei; Huang, Yuan-shen; Zhuang, Song-lin

    2009-09-01

    The UV-responsive detector is a dual-use device for civilian and military after the laser and IR-responsive sensors. Typical image sensor coated with a layer of down-convert frequency thin film on it's photosurface to enhance UV response is the key technology of enhancing UV-response. The UV-enhanced thin film was made in the experimental laboratory using the Zn2SiO4:Mn phosphor by spin coating method. Two peaks at 520 and 560 nm respectively in the emission spectrum of the UV-enhanced film were found by SP1702 spectrograph when the excitation wavelength was 260 and 280 nm. The peaks were found in the process of experiment of measuring and counting the quantum efficiency of UV-enhanced thin film. But the light peaks at 520 and 560 nm are not the emission light peaks by the exciting light of 260 and 280 nm. The reason why the light at 520 and 560 nm is not the emission light was analyzed based on the measurement principle of grating spectrograph. The reasons for the multi-wavelength of light overlaps during the measurement of emission spectrum were also discussed. And the equipment used to separate the overlapped different wavelengths was designed, which will be used to resolve the problem of the overlap of multi-wavelength.

  11. Two-dimensional sub-half-wavelength atom localization via controlled spontaneous emission.

    Science.gov (United States)

    Wan, Ren-Gang; Zhang, Tong-Yi

    2011-12-05

    We propose a scheme for two-dimensional (2D) atom localization based on the controlled spontaneous emission, in which the atom interacts with two orthogonal standing-wave fields. Due to the spatially dependent atom-field interaction, the position probability distribution of the atom can be directly determined by measuring the resulting spontaneously emission spectrum. The phase sensitive property of the atomic system leads to quenching of the spontaneous emission in some regions of the standing-waves, which significantly reduces the uncertainty in the position measurement of the atom. We find that the frequency measurement of the emitted light localizes the atom in half-wavelength domain. Especially the probability of finding the atom at a particular position can reach 100% when a photon with certain frequency is detected. By increasing the Rabi frequencies of the driving fields, such 2D sub-half-wavelength atom localization can acquire high spatial resolution.

  12. Enhancement and wavelength-shifted emission of Cerenkov luminescence using multifunctional microspheres

    International Nuclear Information System (INIS)

    Li, Joanne; Dobrucki, Lawrence W; Marjanovic, Marina; Chaney, Eric J; Suslick, Kenneth S; Boppart, Stephen A

    2015-01-01

    Cerenkov luminescence (CL) imaging is a new molecular imaging modality that utilizes the photons emitted during radioactive decay when charged particles travel faster than the phase velocity of light in a dielectric medium. Here we present a novel agent to convert and increase CL emission at longer wavelengths using multimodal protein microspheres (MSs). The 64 Cu-labeled protein microspheres contain quantum dots (QDs) encapsulated within a high-refractive-index-oil core. Dark box imaging of the MSs was conducted to demonstrate the improvement in CL emission at longer wavelengths. To illustrate the versatile design of these MSs and the potential of CL in disease diagnosis, these MSs were utilized for in vitro cell targeting and ex vivo CL-excited QD fluorescence (CL-FL) imaging of atherosclerotic plaques in rats. It was shown that by utilizing both QDs and MSs with a high-refractive-index-oil core, the CL emission increases by four-fold at longer wavelengths. Furthermore, we demonstrate that these MSs generate both an in vivo and ex vivo contrast signal. The design concept of utilizing QDs and high-index core MSs may contribute to future developments of in vivo CL imaging. (paper)

  13. Efficient color-tunable multiexcitonic dual wavelength emission from Type II semiconductor tetrapods.

    Science.gov (United States)

    Wu, Wen-Ya; Li, Mingjie; Lian, Jie; Wu, Xiangyang; Yeow, Edwin K L; Jhon, Mark H; Chan, Yinthai

    2014-09-23

    We synthesized colloidal InP/ZnS seeded CdS tetrapods by harnessing the structural stability of the InP/ZnS seed nanocrystals at the high reaction temperatures needed to grow the CdS arms. Because of an unexpected Type II band alignment at the interface of the InP/ZnS core and CdS arms that enhanced the occurrence of radiative excitonic recombination in CdS, these tetrapods were found to be capable of exhibiting highly efficient multiexcitonic dual wavelength emission of equal intensity at spectrally distinct wavelengths of ∼485 and ∼675 nm. Additionally, the Type II InP/ZnS seeded CdS tetrapods displayed a wider range of pump-dependent emission color-tunability (from red to white to blue) within the context of a CIE 1931 chromaticity diagram and possessed higher photostability due to suppressed multiexcitonic Auger recombination when compared to conventional Type I CdSe seeded CdS tetrapods. By employing time-resolved spectroscopy measurements, we were able to attribute the wide emission color-tunability to the large valence band offset between InP and CdS. This work highlights the importance of band alignment in the synthetic design of semiconductor nanoheterostructures, which can exhibit color-tunable multiwavelength emission with high efficiency and photostability.

  14. Improving the submicro determination of vanadium in natural water using primary-secondary wavelength spectrophotometry

    International Nuclear Information System (INIS)

    Khongven Gao

    1999-01-01

    In acidic solution and in the presence of ammonium persulfate, the conventional reaction of vanadium(5) with gallic acid to form an orange complex has been used for the improvement of the determination of trace amounts of vanadium in water by the updated method named primary-secondary wavelength spectrophotometry. The results show that the analytical precision and accuracy were improved and gave higher determination sensitivity than ordinary spectrophotometry. The relative standard deviations were less than 5.6 % [ru

  15. Multi-wavelength emission from 3C 66A: clues to its redshift and gamma-ray emission location

    International Nuclear Information System (INIS)

    Yan Da-Hai; Fan Zhong-Hui; Zhou Yao; Dai Ben-Zhong

    2013-01-01

    The quasi-simultaneous multi-wavelength emission of TeV blazar 3C 66A is studied by using a one-zone multi-component leptonic jet model. It is found that the quasi-simultaneous spectral energy distribution of 3C 66A can be well reproduced; in particular, the first three months of its average Fermi-LAT spectrum can be well reproduced by the synchrotron self-Compton component plus external Compton component of the broad line region (BLR). Clues to its redshift and gamma-ray emission location are obtained. The results indicate the following. (i) On the redshift: The theoretical intrinsic TeV spectra can be predicted by extrapolating the reproduced GeV spectra. Through comparing these extrapolated TeV spectra with the corrected observed TeV spectra from extragalactic background light, it is suggested that the redshift of 3C 66A could be between 0.1 and 0.3, with the most likely value being ∼ 0.2. (ii) On the gamma-ray emission location: To well reproduce the GeV emission of 3C 66A under different assumptions on the BLR, the gamma-ray emission region is always required to be beyond the inner zone of the BLR. The BLR absorption effect on gamma-ray emission confirms this point.

  16. Controlling the emission wavelength in group III-V semiconductor laser diodes

    KAUST Repository

    Ooi, Boon S.

    2016-12-29

    Methods are provided for modifying the emission wavelength of a semiconductor quantum well laser diode, e.g. by blue shifting the emission wavelength. The methods can be applied to a variety of semiconductor quantum well laser diodes, e.g. group III-V semiconductor quantum wells. The group III-V semiconductor can include AlSb, AlAs, Aln, AlP, BN, GaSb, GaAs, GaN, GaP, InSb, InAs, InN, and InP, and group III-V ternary semiconductors alloys such as AlxGai.xAs. The methods can results in a blue shifting of about 20 meV to 350 meV, which can be used for example to make group III-V semiconductor quantum well laser diodes with an emission that is orange or yellow. Methods of making semiconductor quantum well laser diodes and semiconductor quantum well laser diodes made therefrom are also provided.

  17. Differentiation of ocular fundus fluorophores by fluorescence lifetime imaging using multiple excitation and emission wavelengths

    Science.gov (United States)

    Hammer, M.; Schweitzer, D.; Schenke, S.; Becker, W.; Bergmann, A.

    2006-10-01

    Ocular fundus autofluorescence imaging has been introduced into clinical diagnostics recently. It is in use for the observation of the age pigment lipofuscin, a precursor of age - related macular degeneration (AMD). But other fluorophores may be of interest too: The redox pair FAD - FADH II provides information on the retinal energy metabolism, advanced glycation end products (AGE) indicate protein glycation associated with pathologic processes in diabetes as well as AMD, and alterations in the fluorescence of collagen and elastin in connective tissue give us the opportunity to observe fibrosis by fluorescence imaging. This, however, needs techniques able to differentiate particular fluorophores despite limited permissible ocular exposure as well as excitation wavelength (limited by the transmission of the human ocular lens to >400 nm). We present an ophthalmic laser scanning system (SLO), equipped with picosecond laser diodes (FWHM 100 ps, 446 nm or 468 nm respectively) and time correlated single photon counting (TCSPC) in two emission bands (500 - 560 nm and 560 - 700 nm). The decays were fitted by a bi-exponential model. Fluorescence spectra were measured by a fluorescence spectrometer fluorolog. Upon excitation at 446 nm, the fluorescence of AGE, FAD, and lipofuscin were found to peak at 503 nm, 525 nm, and 600 nm respectively. Accordingly, the statistical distribution of the fluorescence decay times was found to depend on the different excitation wavelengths and emission bands used. The use of multiple excitation and emission wavelengths in conjunction with fluorescence lifetime imaging allows us to discriminate between intrinsic fluorophores of the ocular fundus. Taken together with our knowledge on the anatomical structure of the fundus, these findings suggest an association of the short, middle and long fluorescence decay time to the retinal pigment epithelium, the retina, and connective tissue respectively.

  18. Random laser emission at dual wavelengths in a donor-acceptor dye mixture solution

    Directory of Open Access Journals (Sweden)

    Sunita Kedia

    Full Text Available The work was aimed to generate random laser emissions simultaneously at two wavelengths in a weakly scattering system containing mixture of binary dyes, rhodamine-B (Rh-B and oxazine-170 (O-170 dispersed with ZnO nano-particles serving as scattering centres. Random lasing performances for individual Rh-B dye were extensively studied for varying small signal gain/scatterer density and we found lasing threshold to significantly depend upon number density of dispersed nano-particles. In spite of inefficient pumping, we demonstrated possibility of random lasing in O-170 dye solution on account of resonance energy transfer from Rh-B dye which served as donor. At optimum concentrations of fluorophores and scatterer in dye mixture solution, incoherent random lasing was effectively attained simultaneously at two wavelengths centered 90 nm apart. Dual-emission intensities, lasing thresholds and rate of amplifications could be controlled and made equivalent for both donor and acceptor in dye mixture solution by appropriate choice of concentrations of dyes and scatterers. Keywords: Random lasing, Energy transfer, Rhodamine-B, Oxazine-170, Zinc oxide

  19. Secondary emission electron gun using external primaries

    Science.gov (United States)

    Srinivasan-Rao, Triveni [Shoreham, NY; Ben-Zvi, Ilan [Setauket, NY

    2009-10-13

    An electron gun for generating an electron beam is provided, which includes a secondary emitter. The secondary emitter includes a non-contaminating negative-electron-affinity (NEA) material and emitting surface. The gun includes an accelerating region which accelerates the secondaries from the emitting surface. The secondaries are emitted in response to a primary beam generated external to the accelerating region. The accelerating region may include a superconducting radio frequency (RF) cavity, and the gun may be operated in a continuous wave (CW) mode. The secondary emitter includes hydrogenated diamond. A uniform electrically conductive layer is superposed on the emitter to replenish the extracted current, preventing charging of the emitter. An encapsulated secondary emission enhanced cathode device, useful in a superconducting RF cavity, includes a housing for maintaining vacuum, a cathode, e.g., a photocathode, and the non-contaminating NEA secondary emitter with the uniform electrically conductive layer superposed thereon.

  20. Photonic engineering of highly linearly polarized quantum dot emission at telecommunication wavelengths

    Science.gov (United States)

    Mrowiński, P.; Emmerling, M.; Schneider, C.; Reithmaier, J. P.; Misiewicz, J.; Höfling, S.; Sek, G.

    2018-04-01

    In this work, we discuss a method to control the polarization anisotropy of spontaneous emission from neutral excitons confined in quantum-dot-like nanostructures, namely single epitaxial InAs quantum dashes emitting at telecom wavelengths. The nanostructures are embedded inside lithographically defined, in-plane asymmetric photonic mesa structures, which generate polarization-dependent photonic confinement. First, we study the influence of the photonic confinement on the polarization anisotropy of the emission by photoluminescence spectroscopy, and we find evidence of different contributions to a degree of linear polarization (DOLP), i.e., from the quantum dash and the photonic mesa, in total giving rise to DOLP =0.85 . Then, we perform finite-difference time-domain simulations of photonic confinement, and we calculate the DOLP in a dipole approximation showing well-matched results for the established model. Furthermore, by using numerical calculations, we demonstrate several types of photonic confinements where highly linearly polarized emission with DOLP of about 0.9 is possible by controlling the position of a quantum emitter inside the photonic structure. Then, we elaborate on anisotropic quantum emitters allowing for exceeding DOLP =0.95 in an optimized case, and we discuss the ways towards efficient linearly polarized single photon source at telecom bands.

  1. Analysis of Saturn's Thermal Emission at 2.2-cm Wavelength: Spatial Distribution of Ammonia Vapor

    Science.gov (United States)

    Laraia, A. L.; Ingersoll, A. P.; Janssen, Michael A.; Gulkis, Samuel; Oyafuso, Fabiano A.; Allison, Michael D.

    2013-01-01

    This work focuses on determining the latitudinal structure of ammonia vapor in Saturn's cloud layer near 1.5 bars using the brightness temperature maps derived from the Cassini RADAR (Elachi et al., 2004) instrument, which works in a passive mode to measure thermal emission from Saturn at 2.2-cm wavelength. We perform an analysis of five brightness temperature maps that span epochs from 2005 to 2011, which are presented in a companion paper by Janssen et al. (2013a, this issue). The brightness temperature maps are representative of the spatial distribution of ammonia vapor, since ammonia gas is the only effective opacity source in Saturn's atmosphere at 2.2-cm wavelength. Relatively high brightness temperatures indicate relatively low ammonia relative humidity (RH), and vice versa. We compare the observed brightness temperatures to brightness temperatures computed using the Juno atmospheric microwave radiative transfer (JAMRT) program which includes both the means to calculate a tropospheric atmosphere model for Saturn and the means to carry out radiative transfer calculations at microwave frequencies. The reference atmosphere to which we compare has a 3x solar deep mixing ratio of ammonia (we use 1.352x10(exp -4) for the solar mixing ratio of ammonia vapor relative to H2; see Atreya, 2010) and is fully saturated above its cloud base. The maps are comprised of residual brightness temperatures-observed brightness temperature minus the model brightness temperature of the saturated atmosphere.

  2. Interband emission energy in a dilute nitride quaternary semiconductor quantum dot for longer wavelength applications

    Science.gov (United States)

    Mageshwari, P. Uma; Peter, A. John; Lee, Chang Woo; Duque, C. A.

    2016-07-01

    Excitonic properties are studied in a strained Ga1-xInxNyAs1-y/GaAs cylindrical quantum dot. The optimum condition for the desired band alignment for emitting wavelength 1.55 μm is investigated using band anticrossing model and the model solid theory. The band gap and the band discontinuities of a Ga1-xInxNyAs1-y/GaAs quantum dot on GaAs are computed with the geometrical confinement effect. The binding energy of the exciton, the oscillator strength and its radiative life time for the optimum condition are found taking into account the spatial confinement effect. The effects of geometrical confinement and the nitrogen incorporation on the interband emission energy are brought out. The result shows that the desired band alignment for emitting wavelength 1.55 μm is achieved for the inclusion of alloy contents, y=0.0554% and x=0.339% in Ga1-xInxNyAs1-y/GaAs quantum dot. And the incorporation of nitrogen and indium shows the red-shift and the geometrical confinement shows the blue-shift. And it can be applied for fibre optical communication networks.

  3. The Peculiar Binary System AE Aquarii from its Characteristic Multi-wavelength Emission

    Directory of Open Access Journals (Sweden)

    Oruru B.

    2014-01-01

    Full Text Available The multi-wavelength properties of the novalike variable system AE Aquarii are discussed in terms of the interaction between the accretion inflow from a late-type main sequence star and the magnetosphere of a fast rotating white dwarf. This results in an efficient magnetospheric propeller process and particle acceleration. The spin-down of the white dwarf at a period rate of 5.64×10−14 s s−1 results in a huge spin-down luminosity of Ls−d ≃ 6 10×33 erg s−1. Hence, the observed non-thermal hard X-ray emission and VHE and TeV gamma-ray emission may suggest that AE Aquarii can be placed in the category of spin-powered pulsars. Besides, observed hard X-ray luminosity of LX,hard ≤ 5 × 1030 erg s−1 constitutes 0.1 % of the total spin-down luminosity of the white dwarf. This paper will discuss some recent theoretical studies and data analysis of the system.

  4. Continental anthropogenic primary particle number emissions

    Science.gov (United States)

    Paasonen, Pauli; Kupiainen, Kaarle; Klimont, Zbigniew; Visschedijk, Antoon; Denier van der Gon, Hugo A. C.; Amann, Markus

    2016-06-01

    Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas-Air Pollution Interactions and Synergies) model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa), coke production (Russia and China), and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation) scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol-cloud interactions as well as particle number related adverse health effects, e.g. in response to tightening

  5. Continental anthropogenic primary particle number emissions

    Directory of Open Access Journals (Sweden)

    P. Paasonen

    2016-06-01

    Full Text Available Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas–Air Pollution Interactions and Synergies model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa, coke production (Russia and China, and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol–cloud interactions as well as particle number related adverse health effects, e.g. in response

  6. Investigation of black and brown carbon multiple-wavelength-dependent light absorption from biomass and fossil fuel combustion source emissions

    Science.gov (United States)

    Michael R. Olson; Mercedes Victoria Garcia; Michael A. Robinson; Paul Van Rooy; Mark A. Dietenberger; Michael Bergin; James Jay Schauer

    2015-01-01

    Quantification of the black carbon (BC) and brown carbon (BrC) components of source emissions is critical to understanding the impact combustion aerosols have on atmospheric light absorption. Multiple-wavelength absorption was measured from fuels including wood, agricultural biomass, coals, plant matter, and petroleum distillates in controlled combustion settings....

  7. Excitation and emission wavelength ratiometric cyanide-sensitive probes for physiological sensing.

    Science.gov (United States)

    Badugu, Ramachandram; Lakowicz, Joseph R; Geddes, Chris D

    2004-04-01

    We characterize three new fluorescent probes that show both spectral shifts and intensity changes in the presence of aqueous cyanide, allowing for both excitation and fluorescence emission wavelength ratiometric and colorimetric sensing. The relatively high binding constants of the probes for cyanide enables a distinct colorimetric change to be visually observed with as little as 10 microM cyanide. The response of the new probes is based on the ability of the boronic acid group to interact with the CN(-) anion, changing from the neutral form of the boronic acid group R-B(OH)(2) to the anionic R-B(-)(OH)3 form, which is an electron-donating group. The presence of an electron-deficient quaternary heterocyclic nitrogen center and a strong electron-donating amino group in the 6 position on the quinolinium backbone provides for the spectral changes observed upon CN(-) complexation. We have determined the binding constants for the ortho-, meta-, and para-boronic acid probes to be 0.12, 0.17, and 0.14 microM(-3). In addition we have synthesized a control compound that does not contain the boronic acid moiety, allowing for structural comparisons and a rationale for the sensing mechanism to be made. Finally we show that the affinity for monosaccharides, such as glucose or fructose, is relatively low as compared to that for cyanide, enabling the potential detection of cyanide in physiologies up to lethal levels.

  8. Short-wavelength out-of-band EUV emission from Sn laser-produced plasma

    Science.gov (United States)

    Torretti, F.; Schupp, R.; Kurilovich, D.; Bayerle, A.; Scheers, J.; Ubachs, W.; Hoekstra, R.; Versolato, O. O.

    2018-02-01

    We present the results of spectroscopic measurements in the extreme ultraviolet regime (7-17 nm) of molten tin microdroplets illuminated by a high-intensity 3 J, 60 ns Nd:YAG laser pulse. The strong 13.5 nm emission from this laser-produced plasma (LPP) is of relevance for next-generation nanolithography machines. Here, we focus on the shorter wavelength features between 7 and 12 nm which have so far remained poorly investigated despite their diagnostic relevance. Using flexible atomic code calculations and local thermodynamic equilibrium arguments, we show that the line features in this region of the spectrum can be explained by transitions from high-lying configurations within the Sn{}8+-Sn{}15+ ions. The dominant transitions for all ions but Sn{}8+ are found to be electric-dipole transitions towards the n = 4 ground state from the core-excited configuration in which a 4p electron is promoted to the 5s subshell. Our results resolve some long-standing spectroscopic issues and provide reliable charge state identification for Sn LPP, which could be employed as a useful tool for diagnostic purposes.

  9. Long-wavelength stimulated emission and carrier lifetimes in HgCdTe-based waveguide structures with quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Rumyantsev, V. V., E-mail: rumyantsev@ipm.sci-nnov.ru; Fadeev, M. A.; Morozov, S. V.; Dubinov, A. A.; Kudryavtsev, K. E.; Kadykov, A. M. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Tuzov, I. V. [Lobachevsky State University of Nizhny Novgorod (NNSU) (Russian Federation); Dvoretskii, S. A.; Mikhailov, N. N. [Russian Academy of Sciences, Institute for Semiconductor Physics, Siberian Branch (Russian Federation); Gavrilenko, V. I. [Novosibirsk State University (Russian Federation); Teppe, F. [Universite Montpellier II, Laboratoire Charles Coulomb (L2C) (France)

    2016-12-15

    The interband photoconductivity and photoluminescence in narrow-gap HgCdTe-based waveguide structures with quantum wells (QWs) (designed for long-wavelength stimulated emission under optical pumping) are investigated. The photoconductivity relaxation times in n-type structures reach several microseconds, due to which stimulated emission at a wavelength of 10.2 μm occurs at a low threshold pump intensity (~100 W/cm{sup 2}) at 20 K. In the p-type structures obtained by annealing (to increase the mercury vacancy concentration), even spontaneous emission from the QWs is not detected because of a dramatic decrease in the carrier lifetime with respect to Shockley–Read–Hall nonradiative recombination.

  10. Intense, stable and excitation wavelength-independent photoluminescence emission in the blue-violet region from phosphorene quantum dots

    Science.gov (United States)

    Ge, Shuaipeng; Zhang, Lisheng; Wang, Peijie; Fang, Yan

    2016-01-01

    Nanoscale phosphorene quantum dots (PQDs) with few-layer structures were fabricated by pulsed laser ablation of a bulk black phosphorus target in diethyl ether. An intense and stable photoluminescence (PL) emission of the PQDs in the blue-violet wavelength region is clearly observed for the first time, which is attributed to electronic transitions from the lowest unoccupied molecular orbital (LUMO) to the highest occupied molecular orbital (HOMO) and occupied molecular orbitals below the HOMO (H-1, H-2), respectively. Surprisingly, the PL emission peak positions of the PQDs are not red-shifted with progressively longer excitation wavelengths, which is in contrast to the cases of graphene and molybdenum disulphide quantum dots. This excitation wavelength-independence is derived from the saturated passivation on the periphery and surfaces of the PQDs by large numbers of electron-donating functional groups which cause the electron density on the PQDs to be dramatically increased and the band gap to be insensitive to the quantum size effect in the PQDs. This work suggests that PQDs with intense, stable and excitation wavelength-independent PL emission in the blue-violet region have a potential application as semiconductor-based blue-violet light irradiation sources. PMID:27265198

  11. Double pulse laser induced breakdown spectroscopy: Experimental study of lead emission intensity dependence on the wavelengths and sample matrix

    Energy Technology Data Exchange (ETDEWEB)

    Piscitelli S, V; Martinez L, M A; Fernandez C, A J [Laboratorio de Espectroscopia Laser, Escuela de Quimica, Facultad de Ciencias, Universidad Central de Venezuela, Caracas, DC 1020 (Venezuela, Bolivarian Republic of); Gonzalez, J J; Mao, X L [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Russo, R.E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)], E-mail: RERusso@lbl.gov

    2009-02-15

    Lead (Pb) emission intensity (atomic line 405.78 nm) dependence on the sample matrix (metal alloy) was studied by means of collinear double pulse (DP)-laser induced breakdown spectroscopy (LIBS). The measurement of the emission intensity produced by three different wavelength combinations (i.e. I:532 nm-II:1064 nm, I:532 nm-II:532 nm, and I:532 nm-II:355 nm) from three series of standard reference materials showed that the lead atomic line 405.78 nm emission intensity was dependent on the sample matrix for all the combination of wavelengths, however reduced dependency was found for the wavelength combination I:532 nm-II:355 nm. Two series of standard reference materials from the National Institute of Standards and Technology (NIST) and one series from the British Chemical Standards (BCS) were used for these experiments. Calibration curves for lead ablated from NIST 626-630 ('Zn{sub 95}Al{sub 4}Cu{sub 1}') provided higher sensitivity (slope) than those calibration curves produced from NIST 1737-1741 ('Zn{sub 99.5}Al{sub 0.5}') and with the series BCS 551-556 ('Cu{sub 87}Sn{sub 11}'). Similar trends between lead emission intensity (calibration curve sensitivities) and reported variations in plasma temperatures caused by the differing ionization potentials of the major and minor elements in these samples were established.

  12. Primary anthropogenic aerosol emission trends for China, 1990–2005

    Directory of Open Access Journals (Sweden)

    Y. Lei

    2011-02-01

    Full Text Available An inventory of anthropogenic primary aerosol emissions in China was developed for 1990–2005 using a technology-based approach. Taking into account changes in the technology penetration within industry sectors and improvements in emission controls driven by stricter emission standards, a dynamic methodology was derived and implemented to estimate inter-annual emission factors. Emission factors of PM2.5 decreased by 7%–69% from 1990 to 2005 in different industry sectors of China, and emission factors of TSP decreased by 18%–80% as well, with the measures of controlling PM emissions implemented. As a result, emissions of PM2.5 and TSP in 2005 were 11.0 Tg and 29.7 Tg, respectively, less than what they would have been without the adoption of these measures. Emissions of PM2.5, PM10 and TSP presented similar trends: they increased in the first six years of 1990s and decreased until 2000, then increased again in the following years. Emissions of TSP peaked (35.5 Tg in 1996, while the peak of PM10 (18.8 Tg and PM2.5 (12.7 Tg emissions occurred in 2005. Although various emission trends were identified across sectors, the cement industry and biofuel combustion in the residential sector were consistently the largest sources of PM2.5 emissions, accounting for 53%–62% of emissions over the study period. The non-metallic mineral product industry, including the cement, lime and brick industries, accounted for 54%–63% of national TSP emissions. There were no significant trends of BC and OC emissions until 2000, but the increase after 2000 brought the peaks of BC (1.51 Tg and OC (3.19 Tg emissions in 2005. Although significant improvements in the estimation of primary aerosols are presented here, there still exist large uncertainties. More accurate and detailed activity information and emission factors based on local tests are essential to further improve emission estimates

  13. MULTI-WAVELENGTH RADIO CONTINUUM EMISSION STUDIES OF DUST-FREE RED GIANTS

    Energy Technology Data Exchange (ETDEWEB)

    O' Gorman, Eamon; Harper, Graham M. [School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Brown, Alexander [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Drake, Stephen [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Richards, Anita M. S. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)

    2013-10-01

    Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones. Such stars are feeble emitters at these wavelengths, however, and previous observations have provided only a small number of modest signal-to-noise measurements slowly accumulated over three decades. We present multi-wavelength Karl G. Jansky Very Large Array thermal continuum observations of the wind acceleration zones of two dust-free red giants, Arcturus (α Boo: K2 III) and Aldebaran (α Tau: K5 III). Importantly, most of our observations of each star were carried out over just a few days, so that we obtained a snapshot of the different stellar atmospheric layers sampled at different wavelengths, independent of any long-term variability. We report the first detections at several wavelengths for each star including a detection at 10 cm (3.0 GHz: S band) for both stars and a 20 cm (1.5 GHz: L band) detection for α Boo. This is the first time single (non-binary) luminosity class III red giants have been detected at these continuum wavelengths. Our long-wavelength data sample the outer layers of α Boo's atmosphere where its wind velocity is approaching (or possibly has reached) its terminal value and the ionization balance is becoming frozen-in. For α Tau, however, our long-wavelength data are still sampling its inner atmosphere, where the wind is still accelerating probably due to its lower mass-loss rate. We compare our data with published semi-empirical models based on ultraviolet data, and the marked deviations highlight the need for new atmospheric models to be developed. Spectral indices are used to discuss the possible properties of the stellar atmospheres, and we find evidence for a rapidly cooling wind in the case of α Boo. Finally, we develop a simple analytical wind model for α Boo based on our new long-wavelength flux measurements.

  14. MULTI-WAVELENGTH RADIO CONTINUUM EMISSION STUDIES OF DUST-FREE RED GIANTS

    International Nuclear Information System (INIS)

    O'Gorman, Eamon; Harper, Graham M.; Brown, Alexander; Drake, Stephen; Richards, Anita M. S.

    2013-01-01

    Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones. Such stars are feeble emitters at these wavelengths, however, and previous observations have provided only a small number of modest signal-to-noise measurements slowly accumulated over three decades. We present multi-wavelength Karl G. Jansky Very Large Array thermal continuum observations of the wind acceleration zones of two dust-free red giants, Arcturus (α Boo: K2 III) and Aldebaran (α Tau: K5 III). Importantly, most of our observations of each star were carried out over just a few days, so that we obtained a snapshot of the different stellar atmospheric layers sampled at different wavelengths, independent of any long-term variability. We report the first detections at several wavelengths for each star including a detection at 10 cm (3.0 GHz: S band) for both stars and a 20 cm (1.5 GHz: L band) detection for α Boo. This is the first time single (non-binary) luminosity class III red giants have been detected at these continuum wavelengths. Our long-wavelength data sample the outer layers of α Boo's atmosphere where its wind velocity is approaching (or possibly has reached) its terminal value and the ionization balance is becoming frozen-in. For α Tau, however, our long-wavelength data are still sampling its inner atmosphere, where the wind is still accelerating probably due to its lower mass-loss rate. We compare our data with published semi-empirical models based on ultraviolet data, and the marked deviations highlight the need for new atmospheric models to be developed. Spectral indices are used to discuss the possible properties of the stellar atmospheres, and we find evidence for a rapidly cooling wind in the case of α Boo. Finally, we develop a simple analytical wind model for α Boo based on our new long-wavelength flux measurements

  15. Multi-wavelength Radio Continuum Emission Studies of Dust-free Red Giants

    Science.gov (United States)

    O'Gorman, Eamon; Harper, Graham M.; Brown, Alexander; Dranke, Stephen; Richards, Anita M. S.

    2013-01-01

    Multi-wavelength centimeter continuum observations of non-dusty, non-pulsating K spectral-type red giants directly sample their chromospheres and wind acceleration zones. Such stars are feeble emitters at these wavelengths, however, and previous observations have provided only a small number of modest signal-to-noise measurements slowly accumulated over three decades. We present multi-wavelength Karl G. Jansky Very Large Array thermal continuum observations of the wind acceleration zones of two dust-free red giants, Arcturus (alpha Boo: K2 III) and Aldebaran (alpha Tau: K5 III). Importantly, most of our observations of each star were carried out over just a few days, so that we obtained a snapshot of the different stellar atmospheric layers sampled at different wavelengths, independent of any long-term variability. We report the first detections at several wavelengths for each star including a detection at 10 cm (3.0 GHz: S band) for both stars and a 20 cm (1.5 GHz: L band) detection for alpha Boo. This is the first time single (non-binary) luminosity class III red giants have been detected at these continuum wavelengths. Our long-wavelength data sample the outer layers of alpha Boo's atmosphere where its wind velocity is approaching (or possibly has reached) its terminal value and the ionization balance is becoming frozen-in. For alpha Tau, however, our long-wavelength data are still sampling its inner atmosphere, where the wind is still accelerating probably due to its lower mass-loss rate. We compare our data with published semi-empirical models based on ultraviolet data, and the marked deviations highlight the need for new atmospheric models to be developed. Spectral indices are used to discuss the possible properties of the stellar atmospheres, and we find evidence for a rapidly cooling wind in the case of alpha Boo. Finally, we develop a simple analytical wind model for alpha Boo based on our new long-wavelength flux measurements.

  16. The pre-launch Planck Sky Model: a model of sky emission at submillimetre to centimetre wavelengths

    CERN Document Server

    Delabrouille, J.; Melin, J.-B.; Miville-Deschenes, M.-A.; Gonzalez-Nuevo, J.; Jeune, M.Le; Castex, G.; de Zotti, G.; Basak, S.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A.; Bernard, J.-P.; Bouchet, F.R.; Clements, D.L.; da Silva, A.; Dickinson, C.; Dodu, F.; Dolag, K.; Elsner, F.; Fauvet, L.; Fay, G.; Giardino, G.; Leach, S.; Lesgourgues, J.; Liguori, M.; Macias-Perez, J.F.; Massardi, M.; Matarrese, S.; Mazzotta, P.; Montier, L.; Mottet, S.; Paladini, R.; Partridge, B.; Piffaretti, R.; Prezeau, G.; Prunet, S.; Ricciardi, S.; Roman, M.; Schaefer, B.; Toffolatti, L.

    2012-01-01

    We present the Planck Sky Model (PSM), a parametric model for the generation of all-sky, few arcminute resolution maps of sky emission at submillimetre to centimetre wavelengths, in both intensity and polarisation. Several options are implemented to model the cosmic microwave background, Galactic diffuse emission (synchrotron, free-free, thermal and spinning dust, CO lines), Galactic H-II regions, extragalactic radio sources, dusty galaxies, and thermal and kinetic Sunyaev-Zeldovich signals from clusters of galaxies. Each component is simulated by means of educated interpolations/extrapolations of data sets available at the time of the launch of the Planck mission, complemented by state-of-the-art models of the emission. Distinctive features of the simulations are: spatially varying spectral properties of synchrotron and dust; different spectral parameters for each point source; modeling of the clustering properties of extragalactic sources and of the power spectrum of fluctuations in the cosmic infrared back...

  17. Spectroscopic studies of xenon EUV emission in the 40-80 nm wavelength range using an absolutely calibrated monochromator

    Energy Technology Data Exchange (ETDEWEB)

    Merabet, H [Mathematic and Sciences Unit, Dhofar University, Salalah 211, Sultanate of (Oman); Bista, R [Department of Physics, University of Nevada Reno, Reno, NV 89557 (United States); Bruch, R [Department of Physics, University of Nevada Reno, Reno, NV 89557 (United States); Fuelling, S [Department of Physics, University of Nevada Reno, Reno, NV 89557 (United States)

    2007-03-01

    We have measured and identified numerous Extreme UltraViolet (EUV) radiative line structures arising from xenon (Xe) ions in charge state q = 1 to 10 in the wavelength range 40-80 nm. To obtain reasonable intensities of different charged Xe ions, we have used a compact microwave plasma source which was designed and developed at the Lawrence Berkeley National Laboratory (LBNL). The EUV emission of the ECR plasma has been measured by a 1.5 m grazing incidence monochromator that was absolutely calibrated in the 10-80 nm wavelength range using well known and calibrated EUV light at the Advanced Light Source (ALS), LBNL. This calibration has enabled us to determine absolute intensities of previously measured EUV radiative lines in the wavelengths regions investigated for different ionization stages of Xe. In addition, emission spectra of xenon ions for corresponding measured lines have been calculated. The calculations have been carried out within the relativistic Hartree-Fock (HF) approximation. Results of calculations are found to be in good agreement with current and available experimental and theoretical data.

  18. Modification of erbium photoluminescence excitation spectra for the emission wavelength 1.54 μm in mesoscopic structures

    International Nuclear Information System (INIS)

    Gaponenko, N.V.; Unuchak, D.M.; Mudryi, A.V.; Malyarevich, G.K.; Gusev, O.B.; Stepikhova, M.V.; Krasilnikova, L.V.; Stupak, A.P.; Kleshcheva, S.M.; Samoilovich, M.I.; Tsvetkov, M.Yu.

    2006-01-01

    Photoluminescence excitation (PLE) spectra for the emission wavelength 1.54 μm were studied for erbium-doped xerogels embedded in artificial opals and porous anodic alumina films. Opals were chosen with photonic stop-band in green spectral range, where excitation of 1.54 μm occurs most efficiently. In comparison to the structure erbium-doped titania xerogel/porous anodic alumina/silicon the photoluminescence excitation spectra for 1.54 μm emission wavelength significantly changes for the same xerogels embedded in artificial opals. Enhancement of erbium-related 1.54 μm emission was observed from the structure Fe 2 O 3 xerogel/porous anodic alumina fabricated on silicon, having some incompletely anodized aluminium, under excitation with either the lasing source at 532 nm or xenon lamp. Evident difference in PLE spectra for erbium doped TiO 2 and Fe 2 O 3 xerogels in porous anodic alumina is observed

  19. Planck intermediate results. XIV. Dust emission at millimetre wavelengths in the Galactic plane

    DEFF Research Database (Denmark)

    Ade, P. A. R.; Aghanim, N.; Alves, Marie-Helene

    2014-01-01

    We use Planck HFI data combined with ancillary radio data to study the emissivity index of the interstellar dust emission in the frequency range 100-353 GHz, or 3-0.8 mm, in the Galactic plane. We analyse the region l = 20 degrees-44 degrees and vertical bar b vertical bar...

  20. Effects of laser wavelengths and pulse energy ratio on the emission enhancement in dual pulse LIBS

    International Nuclear Information System (INIS)

    Ahmed, Rizwan; Iqbal, Javed; Baig, M Aslam

    2015-01-01

    We present new studies on the effects of laser wavelengths, pulse energy ratio and interpulse delay between two laser pulses in the collinear dual pulse configuration of laser-induced breakdown spectroscopy (LIBS) on an iron sample in air using the fundamental (1064 nm) and the second harmonics (532 nm) of Nd:YAG lasers. In the dual pulse LIBS, an optimum value of interpulse delay with an appropriate combination of laser wavelengths, and laser pulse energy ratio, yields a 30 times signal intensity enhancement in the neutral iron lines as compared with single pulse LIBS. A comparison in the spatial variations of electron temperature along the axis of the plume expansion in single and double pulse LIBS has also been studied. (letter)

  1. Near-Infrared Phosphorus-Substituted Rhodamine with Emission Wavelength above 700 nm for Bioimaging.

    Science.gov (United States)

    Chai, Xiaoyun; Cui, Xiaoyan; Wang, Baogang; Yang, Fan; Cai, Yi; Wu, Qiuye; Wang, Ting

    2015-11-16

    Phosphorus has been successfully fused into a classic rhodamine framework, in which it replaces the bridging oxygen atom to give a series of phosphorus-substituted rhodamines (PRs). Because of the electron-accepting properties of the phosphorus moiety, which is due to effective σ*-π* interactions and strengthened by the inductivity of phosphine oxide, PR exhibits extraordinary long-wavelength fluorescence emission, elongating to the region above 700 nm, with bathochromic shifts of 140 and 40 nm relative to rhodamine and silicon-substituted rhodamine, respectively. Other advantageous properties of the rhodamine family, including high molar extinction coefficient, considerable quantum efficiency, high water solubility, pH-independent emission, great tolerance to photobleaching, and low cytotoxicity, stay intact in PR. Given these excellent properties, PR is desirable for NIR-fluorescence imaging in vivo. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Light absorption by primary particle emissions from a lignite burning plant

    International Nuclear Information System (INIS)

    Bond, T.C.; Bussemer, M.; Wehner, B.; Keller, S.; Charlson, R.J.; Heintzenberg, J.

    1999-01-01

    Anthropogenic aerosols from the burning of fossil fuels contribute to climate forcing by both scattering and absorbing solar radiation, and estimates of climate forcing by light-absorbing primary particles have recently been published. While the mass and optical properties of emissions are needed for these studies, the available measurements do not characterize the low-technology burning that is thought to contribute a large fraction of light-absorbing material to the global budget. The authors have measured characteristics of particulate matter (PM) emitted from a small, low-technology lignite-burning plant. The PM emission factor is comparable to those used to calculate emission inventories of light-absorbing particles. However, the fine fraction, the absorbing fraction, and the absorption efficiency of the emissions are substantially below assumptions that have been made in inventories of black carbon emissions and calculations of climate forcing. The measurements suggest that nonblack, light-absorbing particles are emitted from low-technology coal burning. As the burning rate increases, the emitted absorption cross-section decreases, and the wavelength dependence of absorption becomes closer to that of black particles

  3. Shifting wavelengths of ultraweak photon emissions from dying melanoma cells: their chemical enhancement and blocking are predicted by Cosic's theory of resonant recognition model for macromolecules.

    Science.gov (United States)

    Dotta, Blake T; Murugan, Nirosha J; Karbowski, Lukasz M; Lafrenie, Robert M; Persinger, Michael A

    2014-02-01

    During the first 24 h after removal from incubation, melanoma cells in culture displayed reliable increases in emissions of photons of specific wavelengths during discrete portions of this interval. Applications of specific filters revealed marked and protracted increases in infrared (950 nm) photons about 7 h after removal followed 3 h later by marked and protracted increases in near ultraviolet (370 nm) photon emissions. Specific wavelengths within the visible (400 to 800 nm) peaked 12 to 24 h later. Specific activators or inhibitors for specific wavelengths based upon Cosic's resonant recognition model elicited either enhancement or diminishment of photons at the specific wavelength as predicted. Inhibitors or activators predicted for other wavelengths, even within 10 nm, were less or not effective. There is now evidence for quantitative coupling between the wavelength of photon emissions and intrinsic cellular chemistry. The results are consistent with initial activation of signaling molecules associated with infrared followed about 3 h later by growth and protein-structural factors associated with ultraviolet. The greater-than-expected photon counts compared with raw measures through the various filters, which also function as reflective material to other photons, suggest that photons of different wavelengths might be self-stimulatory and could play a significant role in cell-to-cell communication.

  4. A superconducting wavelength shifter as primary radiometric source standard in the X-ray range

    Energy Technology Data Exchange (ETDEWEB)

    Klein, R. [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany)], E-mail: roman.klein@ptb.de; Brandt, G.; Cibik, L.; Gerlach, M.; Krumrey, M.; Mueller, P.; Ulm, G. [Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin (Germany); Scheer, M. [BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany)

    2007-10-11

    For more than 20 years, the Physikalisch-Technische Bundesanstalt (PTB) has been using the calculable radiation of bending magnets from the BESSY I and BESSY II electron storage rings in the visible, UV, vacuum-UV (VUV) and X-ray spectral range for radiometry, especially for the calibration of radiation sources and energy-dispersive detectors. Due to its-compared to bending magnets-higher magnetic field, wavelength shifters (WLS) have the potential to extend the usable spectral range for these applications to higher photon energies. Thus, the characteristic energies of BESSY II bending magnet radiation and a 6 T WLS radiation are 2.5 and 11.5 keV, respectively. Within the scope of this work, the properties of the synchrotron radiation from the 6 T WLS have been investigated and compared to theoretical predictions for photon energies up to 150 keV. Good agreement within the experimental uncertainty of several percent was found. Further improvements for a future radiometric use of WLS radiation with low uncertainties will be discussed.

  5. A superconducting wavelength shifter as primary radiometric source standard in the X-ray range

    International Nuclear Information System (INIS)

    Klein, R.; Brandt, G.; Cibik, L.; Gerlach, M.; Krumrey, M.; Mueller, P.; Ulm, G.; Scheer, M.

    2007-01-01

    For more than 20 years, the Physikalisch-Technische Bundesanstalt (PTB) has been using the calculable radiation of bending magnets from the BESSY I and BESSY II electron storage rings in the visible, UV, vacuum-UV (VUV) and X-ray spectral range for radiometry, especially for the calibration of radiation sources and energy-dispersive detectors. Due to its-compared to bending magnets-higher magnetic field, wavelength shifters (WLS) have the potential to extend the usable spectral range for these applications to higher photon energies. Thus, the characteristic energies of BESSY II bending magnet radiation and a 6 T WLS radiation are 2.5 and 11.5 keV, respectively. Within the scope of this work, the properties of the synchrotron radiation from the 6 T WLS have been investigated and compared to theoretical predictions for photon energies up to 150 keV. Good agreement within the experimental uncertainty of several percent was found. Further improvements for a future radiometric use of WLS radiation with low uncertainties will be discussed

  6. A superconducting wavelength shifter as primary radiometric source standard in the X-ray range

    Science.gov (United States)

    Klein, R.; Brandt, G.; Cibik, L.; Gerlach, M.; Krumrey, M.; Müller, P.; Ulm, G.; Scheer, M.

    2007-10-01

    For more than 20 years, the Physikalisch-Technische Bundesanstalt (PTB) has been using the calculable radiation of bending magnets from the BESSY I and BESSY II electron storage rings in the visible, UV, vacuum-UV (VUV) and X-ray spectral range for radiometry, especially for the calibration of radiation sources and energy-dispersive detectors. Due to its—compared to bending magnets—higher magnetic field, wavelength shifters (WLS) have the potential to extend the usable spectral range for these applications to higher photon energies. Thus, the characteristic energies of BESSY II bending magnet radiation and a 6 T WLS radiation are 2.5 and 11.5 keV, respectively. Within the scope of this work, the properties of the synchrotron radiation from the 6 T WLS have been investigated and compared to theoretical predictions for photon energies up to 150 keV. Good agreement within the experimental uncertainty of several percent was found. Further improvements for a future radiometric use of WLS radiation with low uncertainties will be discussed.

  7. 1.3 mm WAVELENGTH VLBI OF SAGITTARIUS A*: DETECTION OF TIME-VARIABLE EMISSION ON EVENT HORIZON SCALES

    International Nuclear Information System (INIS)

    Fish, Vincent L.; Doeleman, Sheperd S.; Beaudoin, Christopher; Bolin, David E.; Rogers, Alan E. E.; Blundell, Ray; Gurwell, Mark A.; Moran, James M.; Primiani, Rurik; Bower, Geoffrey C.; Plambeck, Richard; Chamberlin, Richard; Freund, Robert; Friberg, Per; Honma, Mareki; Oyama, Tomoaki; Inoue, Makoto; Krichbaum, Thomas P.; Lamb, James; Marrone, Daniel P.

    2011-01-01

    Sagittarius A*, the ∼4 x 10 6 M sun black hole candidate at the Galactic center, can be studied on Schwarzschild radius scales with (sub)millimeter wavelength very long baseline interferometry (VLBI). We report on 1.3 mm wavelength observations of Sgr A* using a VLBI array consisting of the JCMT on Mauna Kea, the Arizona Radio Observatory's Submillimeter Telescope on Mt. Graham in Arizona, and two telescopes of the CARMA array at Cedar Flat in California. Both Sgr A* and the quasar calibrator 1924-292 were observed over three consecutive nights, and both sources were clearly detected on all baselines. For the first time, we are able to extract 1.3 mm VLBI interferometer phase information on Sgr A* through measurement of closure phase on the triangle of baselines. On the third night of observing, the correlated flux density of Sgr A* on all VLBI baselines increased relative to the first two nights, providing strong evidence for time-variable change on scales of a few Schwarzschild radii. These results suggest that future VLBI observations with greater sensitivity and additional baselines will play a valuable role in determining the structure of emission near the event horizon of Sgr A*.

  8. Major constituent quantitative determination in uranium alloys by coupled plasma atomic emission spectrometry and X ray fluorescence wavelength dispersive spectrometry

    International Nuclear Information System (INIS)

    Oliveira, Luis Claudio de; Silva, Adriana Mascarenhas Martins da; Gomide, Ricardo Goncalves; Silva, Ieda de Souza

    2013-01-01

    A wavelength-dispersive X-ray fluorescence (WD-XRF) spectrometric method for determination of major constituents elements (Zr, Nb, Mo) in Uranium/Zirconium/Niobium and Uranium/Molybdenum alloy samples were developed. The methods use samples taken in the form of chips that were dissolved in hot nitric acid and precipitate particles melted with lithium tetraborate and dissolved in hot nitric acid and finally analyzed as a solution. Studies on the determination by inductively coupled plasma optic emission spectrometry (ICP OES) using matched matrix in calibration curve were developed. The same samples solution were analyzed in both methods. The limits of detection (LOD), linearity of the calibrations curves, recovery study, accuracy and precision of the both techniques were carried out. The results were compared. (author)

  9. Proportion of influence phases anatase and rutile TiO_2 in the photoluminescence 538 nm emission wavelength

    International Nuclear Information System (INIS)

    Araujo, D.S.; Diniz, V.C.S.; Araujo, P.M.A.G.; Costa, A.C.F.M.; Viana, R.S.; Junior, S.A.

    2016-01-01

    TiO2 is one of the most studied materials in the technology area, especially in photoluminescent applications involving catalysts from the biosensor. Therefore, we propose to obtain the Pechini method TiO_2 molar ratio of citric acid/metal ions of 3:1 and 4:1 in order to investigate the influence of the proportion of anatase and rutile phases with the photoluminescence excitation wavelength of 538nm emission. The samples were characterized by X-ray diffraction, thermal analysis and excitation spectroscopy. The results indicate the presence of two phases, with a proportion of 78.99 and 83.58 and 21.01% of anatase and rutile 16.42%, density 3.82 and 3.70 g/cm"3 and excitement in length wave emission 538nm with maximum intensity 91289.2 and 71880,7 cps for samples 3:1 and 4:1, respectively. Sample 3:1 with the highest percentage of rutile phase favored photoluminescence. (author)

  10. Eta Carinae: Linelist for the Emission Spectrum of the Weigelt Blobs in the 1700-10400Angstrom Wavelength Region

    Science.gov (United States)

    Zethson, T.; Johansson, S.; Hartman, H.; Gull, T. R.

    2011-01-01

    Aims. We present line identifications in the 1700 to 10400A region for the Weigelt Blobs B and D, located 0.1 to 0.3" NNW of Eta Carinae. The aim of this work is to characterize the behavior of these luminous, dense gas condensations in response to the broad maximum and short minimum states of Eta Carinae during its 5.54-year spectroscopic period. Methods. The observations were carried out during March 1998, the minimum spectrum, and in February 1999, early maximum spectrum, with the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) from 1640 to 10400A using the 52"x0.1" aperture centered on Eta Carinae at position angle -28 degrees. Extractions of the reduced spectrum centered on Weigelt B and D, 0.28: in length along the slit, were used to identify the narrow, nebular emission lines, measure their wavelengths and estimate their fluxes. Results. A linelist of 1500 lines is presented for the maximum and minimum states of combined Weigelt blobs B and D. The spectra are dominated by emission lines from the iron-group elements, but include lines from lighter elements. They include parity permitted and forbidden lines. A number of lines are fluorescent lines pumped by H Ly alpha. Other lines show anomalous excitation.

  11. Long wavelength stimulated emission up to 9.5 μm from HgCdTe quantum well heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, S. V.; Rumyantsev, V. V., E-mail: rumyantsev@ipmras.ru; Dubinov, A. A.; Kudryavtsev, K. E.; Antonov, A. V.; Gavrilenko, V. I. [Institute for Physics of Microstructures of Russian Academy of Sciences, 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod (Russian Federation); Kadykov, A. M. [Institute for Physics of Microstructures of Russian Academy of Sciences, 603950 Nizhny Novgorod (Russian Federation); UMR CNRS 5221, GIS-TERALAB, Université Montpellier II, 34095 Montpellier (France); Mikhailov, N. N. [A.V. Rzhanov Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation); Dvoretskii, S. A. [A.V. Rzhanov Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk (Russian Federation)

    2016-02-29

    Stimulated emission from waveguide HgCdTe structures with several quantum wells inside waveguide core is demonstrated at wavelengths up to 9.5 μm. Photoluminescence line narrowing down to kT energy, as well as superlinear rise in its intensity evidence the onset of the stimulated emission, which takes place under optical pumping with intensity as small as ∼0.1 kW/cm{sup 2} at 18 K and 1 kW/cm{sup 2} at 80 K. One can conclude that HgCdTe structures potential for long-wavelength lasers is not exhausted.

  12. Tuning direct bandgap GeSn/Ge quantum dots' interband and intraband useful emission wavelength: Towards CMOS compatible infrared optical devices

    Science.gov (United States)

    Baira, Mourad; Salem, Bassem; Madhar, Niyaz Ahamad; Ilahi, Bouraoui

    2018-05-01

    In this work, interband and intraband optical transitions from direct bandgap strained GeSn/Ge quantum dots are numerically tuned by evaluating the confined energies for heavy holes and electrons in D- and L-valley. The practically exploitable emission wavelength ranges for efficient use in light emission and sensing should fulfill specific criteria imposing the electrons confined states in D-valley to be sufficiently below those in L-valley. This study shows that GeSn quantum dots offer promising opportunity towards high efficient group IV based infrared optical devices operating in the mid-IR and far-IR wavelength regions.

  13. Characterization of selenium in ambient aerosols and primary emission sources.

    Science.gov (United States)

    De Santiago, Arlette; Longo, Amelia F; Ingall, Ellery D; Diaz, Julia M; King, Laura E; Lai, Barry; Weber, Rodney J; Russell, Armistead G; Oakes, Michelle

    2014-08-19

    Atmospheric selenium (Se) in aerosols was investigated using X-ray absorption near-edge structure (XANES) spectroscopy and X-ray fluorescence (XRF) microscopy. These techniques were used to determine the oxidation state and elemental associations of Se in common primary emission sources and ambient aerosols collected from the greater Atlanta area. In the majority of ambient aerosol and primary emission source samples, the spectroscopic patterns as well as the absence of elemental correlations suggest Se is in an elemental, organic, or oxide form. XRF microscopy revealed numerous Se-rich particles, or hotspots, accounting on average for ∼16% of the total Se in ambient aerosols. Hotspots contained primarily Se(0)/Se(-II). However, larger, bulk spectroscopic characterizations revealed Se(IV) as the dominant oxidation state in ambient aerosol, followed by Se(0)/Se(-II) and Se(VI). Se(IV) was the only observed oxidation state in gasoline, diesel, and coal fly ash, while biomass burning contained a combination of Se(0)/Se(-II) and Se(IV). Although the majority of Se in aerosols was in the most toxic form, the Se concentration is well below the California Environmental Protection Agency chronic exposure limit (∼20000 ng/m(3)).

  14. Strain engineering of quantum dots for long wavelength emission: Photoluminescence from self-assembled InAs quantum dots grown on GaAs(001) at wavelengths over 1.55 μm

    International Nuclear Information System (INIS)

    Shimomura, K.; Kamiya, I.

    2015-01-01

    Photoluminescence (PL) at wavelengths over 1.55 μm from self-assembled InAs quantum dots (QDs) grown on GaAs(001) is observed at room temperature (RT) and 4 K using a bilayer structure with thin cap. The PL peak has been known to redshift with decreasing cap layer thickness, although accompanying intensity decrease and peak broadening. With our strain-controlled bilayer structure, the PL intensity can be comparable to the ordinary QDs while realizing peak emission wavelength of 1.61 μm at 4 K and 1.73 μm at RT. The key issue lies in the control of strain not only in the QDs but also in the cap layer. By combining with underlying seed QD layer, we realize strain-driven bandgap engineering through control of strain in the QD and cap layers

  15. Strain engineering of quantum dots for long wavelength emission: Photoluminescence from self-assembled InAs quantum dots grown on GaAs(001) at wavelengths over 1.55 μm

    Energy Technology Data Exchange (ETDEWEB)

    Shimomura, K., E-mail: sd12502@toyota-ti.ac.jp; Kamiya, I., E-mail: kamiya@toyota-ti.ac.jp [Toyota Technological Institute 2-12-1 Hisakata, Tempaku, Nagoya 468-8511 (Japan)

    2015-02-23

    Photoluminescence (PL) at wavelengths over 1.55 μm from self-assembled InAs quantum dots (QDs) grown on GaAs(001) is observed at room temperature (RT) and 4 K using a bilayer structure with thin cap. The PL peak has been known to redshift with decreasing cap layer thickness, although accompanying intensity decrease and peak broadening. With our strain-controlled bilayer structure, the PL intensity can be comparable to the ordinary QDs while realizing peak emission wavelength of 1.61 μm at 4 K and 1.73 μm at RT. The key issue lies in the control of strain not only in the QDs but also in the cap layer. By combining with underlying seed QD layer, we realize strain-driven bandgap engineering through control of strain in the QD and cap layers.

  16. 76 FR 9409 - National Emission Standards for Hazardous Air Pollutants: Primary Lead Smelting

    Science.gov (United States)

    2011-02-17

    ... National Emission Standards for Hazardous Air Pollutants: Primary Lead Smelting; Proposed Rule #0;#0... Emission Standards for Hazardous Air Pollutants: Primary Lead Smelting AGENCY: Environmental Protection... standards for hazardous air pollutants (NESHAP) for Primary Lead Smelting to address the results of the...

  17. A new experimental apparatus for emissivity measurements of steel and the application of multi-wavelength thermometry to continuous casting billets

    Science.gov (United States)

    Wang, Peng; Hu, Zhenwei; Xie, Zhi; Yan, Ming

    2018-05-01

    An experimental apparatus has been designed for measuring the emissivity of a steel surface in both vacuum and oxidation atmosphere. The sample is heated with the method of electromagnetic induction in order to ensure the temperature uniformity. The radiance emitted from a sample is measured using a fiber-optic Fourier transform infrared spectrometer. Using this unique apparatus, we investigated the spectral (2-6 μm) and directional (0°-86°) emissivity of stainless steel 304 with different degrees of surface oxidation at temperatures ranging from 800 to 1100 °C. The experimental results show that the emissivity increases slightly with increasing temperature, which accords with the Hagen-Rubens relation. The emissivity increases rapidly at the initial stage of oxidation, but gradually reaches to a constant value after 20 min. In addition, the directional emissivity has a maximum value at the measuring angle of about 75°. The maximum uncertainty of emissivity is only 3.0% over all the measuring ranges, indicating that this experimental apparatus has a high reliability. In order to measure the surface temperature of casting billets based on multi-wavelength thermometry, the bivariate emissivity function with the two variables, wavelength and temperature, is determined. Temperature measurement results based on our technique are compared with those from common dual-wavelength radiation thermometry. Our approach reduces the measured temperature fluctuation from ±20.7 °C to ±2.8 °C and reflects the temperature variation with the changes of production parameters in real time.

  18. MOVPE prepared InAs/GaAs quantum dots covered by GaAsSb layer with long wavelength emission at 1.8 µm

    Czech Academy of Sciences Publication Activity Database

    Zíková, Markéta; Hospodková, Alice; Pangrác, Jiří; Oswald, Jiří; Krčil, Pavel; Hulicius, Eduard; Komninou, Ph.; Kioseoglou, J.

    2015-01-01

    Roč. 414, Mar (2015), 167-171 ISSN 0022-0248 R&D Projects: GA ČR GA13-15286S; GA MŠk(CZ) LM2011026 Institutional support: RVO:68378271 Keywords : long emission wavelength * photocurrent * InAs quantum dots * MOVPE * GaAsSb layer Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.462, year: 2015

  19. CO_2 emission trends of China's primary aluminum industry: A scenario analysis using system dynamics model

    International Nuclear Information System (INIS)

    Li, Qiang; Zhang, Wenjuan; Li, Huiquan; He, Peng

    2017-01-01

    China announced its promise on CO_2 emission peak. When and what level of CO_2 emission peak China's primary aluminum industry will reach is in suspense. In this paper, a system dynamic model is established, with five subsystems of economy development, primary aluminum production, secondary aluminum production, CO_2 emission intensity and policies making involved. The model is applied to examine potential CO_2 emission trends of China's primary aluminum industry in next fifteen years with three scenarios of “no new policies”, “13th five-year plan” and “additional policies”. Simulation results imply that: merely relying on rapid expansion of domestic scarps recycling and reuse could not mitigate CO_2 emission continuously. Combination of energy-saving technology application and electrolytic technology innovation, as well as promoting hydropower utilization in primary aluminum industry are necessary for long term low-carbon development. From a global prospective, enhancing international cooperation on new primary aluminum capacity construction in other countries, especially with rich low-carbon energy, could bring about essential CO_2 emission for both China's and global primary aluminum industry. - Highlights: • A system dynamic model is established for future CO_2 emission trend of China's primary aluminum industry. • Three potential policy scenarios are simulated. • The impacts of potential policies implication on the CO_2 emission trend are discussed.

  20. MIT wavelength tables. Volume 2. Wavelengths by element

    International Nuclear Information System (INIS)

    Phelps, F.M. III.

    1982-01-01

    This volume is the first stage of a project to expand and update the MIT wavelength tables first compiled in the 1930's. For 109,325 atomic emission lines, arranged by element, it presents wavelength in air, wavelength in vacuum, wave number and intensity. All data are stored on computer-readable magnetic tape

  1. Observations of the polarized emission of Taurus A, Cas A and Cygnus A at 9-mm wavelength

    International Nuclear Information System (INIS)

    Flett, A.M.; Henderson, C.

    1979-01-01

    Measurements of the total intensity and degree of linear polarization of the supernova remnants Taurus A and Cas A and of the radiogalaxy Cygnus A have been made at lambda 9 mm using the 25-m radiotelescope at Chilbolton. A new experimental technique involving Faraday rotation of the incoming polarized radiation was employed. Taurus A shows the expected strong and uniform polarization over the central area investigated, and Cas A the ring-like distribution observed at other wavelengths. The beamwidth of 1.5 arcmin resolves the two major components of Cygnus A and it is found that the polarization in the E component has a position angle of 53 +- 3 0 and P = 7.5 +- 1.2 per cent, and the W component a position angle of 133 +- 3 0 and P = 9.6 +-1.1 per cent. When these results are combined with earlier data at longer wavelengths, the large rotation measure of the E component and the fall of the degree of polarization of the W component at short wavelength are further established. (author)

  2. GHG emissions from primary aluminum production in China: Regional disparity and policy implications

    International Nuclear Information System (INIS)

    Hao, Han; Geng, Yong; Hang, Wen

    2016-01-01

    Highlights: • GHG emissions from primary aluminum production in China were accounted. • The impact of regional disparity of power generation was considered for this study. • GHG emissions factor of China’s primary aluminum production was 16.5 t CO_2e/t Al ingot in 2013. • Total GHG emissions from China’s primary aluminum production were 421 mt CO_2e in 2013. - Abstract: China is the world-leading primary aluminum production country, which contributed to over half of global production in 2014. Primary aluminum production is power-intensive, for which power generation has substantial impact on overall Greenhouse Gas (GHG) emissions. In this study, we explore the impact of regional disparity of China’s power generation system on GHG emissions for the sector of primary aluminum production. Our analysis reveals that the national GHG emissions factor (GEF) of China’s primary aluminum production was 16.5 t CO_2e/t Al ingot in 2013, with province-level GEFs ranging from 8.2 to 21.7 t CO_2e/t Al ingot. There is a high coincidence of provinces with high aluminum productions and high GEFs. Total GHG emissions from China’s primary aluminum production were 421 mt CO_2e in 2013, approximately accounting for 4% of China’s total GHG emissions. Under the 2020 scenario, GEF shows a 13.2% reduction compared to the 2013 level, but total GHG emissions will increase to 551 mt CO_2e. Based on our analysis, we recommend that the government should further promote energy efficiency improvement, facilitate aluminum industry redistribution with low-carbon consideration, promote secondary aluminum production, and improve aluminum industry data reporting and disclosure.

  3. Primary Aluminum Reduction Industry - National Emission Standards for Hazardous Air Pollutants (NESHAP)

    Science.gov (United States)

    National emission standards for each new or existing potline, paste production operation, and anode bake furnace associated with a primary aluminum reduction plant. Includes rule history, implementation information and additional resources.

  4. Monitoring of PM10 and PM2.5 around primary particulate anthropogenic emission sources

    Science.gov (United States)

    Querol, Xavier; Alastuey, Andrés; Rodriguez, Sergio; Plana, Felicià; Mantilla, Enrique; Ruiz, Carmen R.

    Investigations on the monitoring of ambient air levels of atmospheric particulates were developed around a large source of primary anthropogenic particulate emissions: the industrial ceramic area in the province of Castelló (Eastern Spain). Although these primary particulate emissions have a coarse grain-size distribution, the atmospheric transport dominated by the breeze circulation accounts for a grain-size segregation, which results in ambient air particles occurring mainly in the 2.5-10 μm range. The chemical composition of the ceramic particulate emissions is very similar to the crustal end-member but the use of high Al, Ti and Fe as tracer elements as well as a peculiar grain-size distribution in the insoluble major phases allow us to identify the ceramic input in the bulk particulate matter. PM2.5 instead of PM10 monitoring may avoid the interference of crustal particles without a major reduction in the secondary anthropogenic load, with the exception of nitrate. However, a methodology based in PM2.5 measurement alone is not adequate for monitoring the impact of primary particulate emissions (such as ceramic emissions) on air quality, since the major ambient air particles derived from these emissions are mainly in the range of 2.5-10 μm. Consequently, in areas characterised by major secondary particulate emissions, PM2.5 monitoring should detect anthropogenic particulate pollutants without crustal particulate interference, whereas PM10 measurements should be used in areas with major primary anthropogenic particulate emissions.

  5. Wavelength-tuned light emission via modifying the band edge symmetry: Doped SnO2 as an example

    KAUST Repository

    Zhou, Hang; Deng, Rui; Li, Yongfeng; Yao, Bin; Ding, Zhanhui; Wang, Qingxiao; Han, Yu; Wu, Tao; Liu, Lei

    2014-01-01

    at 398 nm is observed in the indium-doped SnO2-based heterojunction. Our results demonstrate an unprecedented doping-based approach toward tailoring the symmetry of band edge states and recovering ultraviolet light emission in wide-bandgap oxides. © 2014

  6. Wavelength-tuned light emission via modifying the band edge symmetry: Doped SnO2 as an example

    KAUST Repository

    Zhou, Hang

    2014-03-27

    We report the observation of ultraviolet photoluminescence and electroluminescence in indium-doped SnO2 thin films with modified "forbidden" bandgap. With increasing indium concentration in SnO 2, dominant visible light emission evolves into the ultraviolet regime in photoluminescence. Hybrid functional first-principles calculations demonstrate that the complex of indium dopant and oxygen vacancy breaks "forbidden" band gap to form allowed transition states. Furthermore, undoped and 10% indium-doped SnO2 layers are synthesized on p-type GaN substrates to obtain SnO2-based heterojunction light-emitting diodes. A dominant visible emission band is observed in the undoped SnO 2-based heterojunction, whereas strong near-ultraviolet emission peak at 398 nm is observed in the indium-doped SnO2-based heterojunction. Our results demonstrate an unprecedented doping-based approach toward tailoring the symmetry of band edge states and recovering ultraviolet light emission in wide-bandgap oxides. © 2014 American Chemical Society.

  7. Stimulated emission of surface plasmon polaritons by lead-sulphide quantum dots at near infra-red wavelengths

    DEFF Research Database (Denmark)

    Radko, Ilya P.; Nielsen, Michael Grøndahl; Albrektsen, Ole

    2010-01-01

    Amplification of surface plasmon polaritons (SPPs) in planar metal-dielectric structure through stimulated emission is investigated using leakage-radiation microscopy configuration. The gain medium is a thin polymethylmethacrylate layer doped with lead-sulphide nanocrystals emitting at near-infrared...

  8. X-ray emission, ablation pressure, and preheating for foils irradiated at 0. 26. mu. m wavelength

    Energy Technology Data Exchange (ETDEWEB)

    Pepin, H.; Fabbro, R.; Faral, B.; Amiranoff, F.; Virmont, J.; Cottet, F.; Romain, J.P.

    1985-11-01

    The x-ray emission, ablation pressure, and preheating for foils irradiated with a 0.26 ..mu..m laser at intensities approx.10/sup 15/ W cm/sup -2/ are studied. The foils are Al with various thicknesses, coated or uncoated with CH or Au. The x-ray emission and conversion efficiency are obtained with a multichannel x-ray diode spectrometer, the ablation pressures are deduced from shock transit times, and the rear temperatures are inferred from x-ray pyrometry. For thin foils (<<12 ..mu..m), the rear temperatures can be predicted reasonably well with the use of the front x-ray spectra. For thick foils shock preheating is dominant.

  9. X-ray emission, ablation pressure, and preheating for foils irradiated at 0.26 μm wavelength

    International Nuclear Information System (INIS)

    Pepin, H.; Fabbro, R.; Faral, B.; Amiranoff, F.; Virmont, J.; Cottet, F.; Romain, J.P.

    1985-01-01

    The x-ray emission, ablation pressure, and preheating for foils irradiated with a 0.26 μm laser at intensities approx.10 15 W cm -2 are studied. The foils are Al with various thicknesses, coated or uncoated with CH or Au. The x-ray emission and conversion efficiency are obtained with a multichannel x-ray diode spectrometer, the ablation pressures are deduced from shock transit times, and the rear temperatures are inferred from x-ray pyrometry. For thin foils (<<12 μm), the rear temperatures can be predicted reasonably well with the use of the front x-ray spectra. For thick foils shock preheating is dominant

  10. Globalization and pollution: tele-connecting local primary PM2.5 emissions to global consumption

    Science.gov (United States)

    Meng, Jing; Liu, Junfeng; Xu, Yuan; Guan, Dabo; Liu, Zhu; Huang, Ye; Tao, Shu

    2016-11-01

    Globalization pushes production and consumption to geographically diverse locations and generates a variety of sizeable opportunities and challenges. The distribution and associated effects of short-lived primary fine particulate matter (PM2.5), a representative of local pollution, are significantly affected by the consumption through global supply chain. Tele-connection is used here to represent the link between production and consumption activity at large distances. In this study, we develop a global consumption-based primary PM2.5 emission inventory to track primary PM2.5 emissions embodied in the supply chain and evaluate the extent to which local PM2.5 emissions are triggered by international trade. We further adopt consumption-based accounting and identify the global original source that produced the emissions. We find that anthropogenic PM2.5 emissions from industrial sectors accounted for 24 Tg globally in 2007; approximately 30% (7.2 Tg) of these emissions were embodied in export of products principally from Brazil, South Africa, India and China (3.8 Tg) to developed countries. Large differences (up to 10 times) in the embodied emissions intensity between net importers and exporters greatly increased total global PM2.5 emissions. Tele-connecting production and consumption activity provides valuable insights with respect to mitigating long-range transboundary air pollution and prompts concerted efforts aiming at more environmentally conscious globalization.

  11. Tracing Primary PM2.5 emissions via Chinese supply chains

    Science.gov (United States)

    Meng, Jing; Liu, Junfeng; Xu, Yuan; Tao, Shu

    2015-05-01

    In this study, we examine a supply-chain approach to more effectively mitigate primary PM2.5 emissions in China from the perspectives of production, consumption and their linkages using structural path analysis. We identify the pattern of all supply chain paths using principal component analysis. To address the severe haze problems in China, it is important to understand how final demand purchase initiates production processes and ultimately leads to primary PM2.5 emission. We found that consumers’ demands on power and transportation mainly induce direct emissions, quite different from the demands on construction, industry and service products which largely drive emissions in upstream activities. We also found that nearly 80% of the economic sectors in China follow a similar pattern in generating primary PM2.5 emissions in electricity, cement and the ferrous metal industries; but only the construction sector increases the release of PM2.5 due to the production of non-metallic mineral products. These findings indicate that further reduction of end-of-pipe emissions in the power and transportation sectors will facilitate cleaner production in almost all the economic sectors. However, for urbanization induced emissions, China should mitigate PM2.5 emissions through the supply chain of construction, either severely reducing its life-cycle intensity or carefully planning to avoid extensive, unnecessary building activity.

  12. Tracing Primary PM2.5 emissions via Chinese supply chains

    International Nuclear Information System (INIS)

    Meng, Jing; Liu, Junfeng; Tao, Shu; Xu, Yuan

    2015-01-01

    In this study, we examine a supply-chain approach to more effectively mitigate primary PM 2.5 emissions in China from the perspectives of production, consumption and their linkages using structural path analysis. We identify the pattern of all supply chain paths using principal component analysis. To address the severe haze problems in China, it is important to understand how final demand purchase initiates production processes and ultimately leads to primary PM 2.5 emission. We found that consumers’ demands on power and transportation mainly induce direct emissions, quite different from the demands on construction, industry and service products which largely drive emissions in upstream activities. We also found that nearly 80% of the economic sectors in China follow a similar pattern in generating primary PM 2.5 emissions in electricity, cement and the ferrous metal industries; but only the construction sector increases the release of PM 2.5 due to the production of non-metallic mineral products. These findings indicate that further reduction of end-of-pipe emissions in the power and transportation sectors will facilitate cleaner production in almost all the economic sectors. However, for urbanization induced emissions, China should mitigate PM 2.5 emissions through the supply chain of construction, either severely reducing its life-cycle intensity or carefully planning to avoid extensive, unnecessary building activity. (letter)

  13. Globalization and pollution: tele-connecting local primary PM2.5 emissions to global consumption

    Science.gov (United States)

    Meng, Jing; Xu, Yuan; Guan, Dabo; Liu, Zhu; Huang, Ye; Tao, Shu

    2016-01-01

    Globalization pushes production and consumption to geographically diverse locations and generates a variety of sizeable opportunities and challenges. The distribution and associated effects of short-lived primary fine particulate matter (PM2.5), a representative of local pollution, are significantly affected by the consumption through global supply chain. Tele-connection is used here to represent the link between production and consumption activity at large distances. In this study, we develop a global consumption-based primary PM2.5 emission inventory to track primary PM2.5 emissions embodied in the supply chain and evaluate the extent to which local PM2.5 emissions are triggered by international trade. We further adopt consumption-based accounting and identify the global original source that produced the emissions. We find that anthropogenic PM2.5 emissions from industrial sectors accounted for 24 Tg globally in 2007; approximately 30% (7.2 Tg) of these emissions were embodied in export of products principally from Brazil, South Africa, India and China (3.8 Tg) to developed countries. Large differences (up to 10 times) in the embodied emissions intensity between net importers and exporters greatly increased total global PM2.5 emissions. Tele-connecting production and consumption activity provides valuable insights with respect to mitigating long-range transboundary air pollution and prompts concerted efforts aiming at more environmentally conscious globalization. PMID:27956874

  14. Globalization and pollution: tele-connecting local primary PM2.5 emissions to global consumption.

    Science.gov (United States)

    Meng, Jing; Liu, Junfeng; Xu, Yuan; Guan, Dabo; Liu, Zhu; Huang, Ye; Tao, Shu

    2016-11-01

    Globalization pushes production and consumption to geographically diverse locations and generates a variety of sizeable opportunities and challenges. The distribution and associated effects of short-lived primary fine particulate matter (PM 2.5 ), a representative of local pollution, are significantly affected by the consumption through global supply chain. Tele-connection is used here to represent the link between production and consumption activity at large distances. In this study, we develop a global consumption-based primary PM 2.5 emission inventory to track primary PM 2.5 emissions embodied in the supply chain and evaluate the extent to which local PM 2.5 emissions are triggered by international trade. We further adopt consumption-based accounting and identify the global original source that produced the emissions. We find that anthropogenic PM 2.5 emissions from industrial sectors accounted for 24 Tg globally in 2007; approximately 30% (7.2 Tg) of these emissions were embodied in export of products principally from Brazil, South Africa, India and China (3.8 Tg) to developed countries. Large differences (up to 10 times) in the embodied emissions intensity between net importers and exporters greatly increased total global PM 2.5 emissions. Tele-connecting production and consumption activity provides valuable insights with respect to mitigating long-range transboundary air pollution and prompts concerted efforts aiming at more environmentally conscious globalization.

  15. Inventory of primary particulates emissions; Inventaire des emissions de particules primaires

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-12-01

    CITEPA carried out a national inventory on particulate emissions. This report presents the results of this study for a great number of sectors and it covers a larger number of sources than the previous CITEPA inventories on particles and some other inventories carried out by International organisms (TNO, IIASA). In particular, at the present time, fugitive dust emissions for some sources are rarely taken into account in inventories because of poor knowledge and they are still the subject of researches in order to validate the emission results. (author)

  16. [Effect of different excitation monitoring wavelengths on emission spectrum of red long afterglow phosphor Sr3Al2O6 : Eu2+, Dy3+].

    Science.gov (United States)

    Cui, Cai-e; Li, Jian; Huang, Ping; Liang, Li-ping; Wu, Yin-lan

    2012-01-01

    The Eu2+ and Dy3+ ion co-doped Sr3Al2O6 phosphor powders with long afterglow were prepared with high temperature solid-state reaction. The phase and the spectra properties of the material were characterized by X-ray diffraction (XRD) and fluorescence spectrophotometer. It was found that the sample is composed of pure Sr3Al2O6 phase. Furthermore, the emission peak of 537 nm under 360 nm excitation and that of 590 nm excited by 468 nm-light were obtained, respectively, and it is more interesting that the emission peaks were at 537 and 590 nm under 394 nm excitation. The effects of different excitation wavelengths on the emission spectrum were explained reasonably by the effect of nephelauxetic effect and crystal field. It revealed that the two types of luminescence with different color were caused by the differences of the center of gravity of the 5d excited state energy level and the split range of 5d energy level.

  17. Spectral emissivities at wavelengths in the range 500--653 nm, enthalpies, and heat capacities of the liquid phases of cobalt, titanium, and zirconium

    International Nuclear Information System (INIS)

    Qin, J.; Roesner-Kuhn, M.; Drewes, K.; Thiedemann, U.; Kuppermann, G.; Camin, B.; Blume, R.; Frohberg, M.G.

    1997-01-01

    A review is given of the literature data for spectral emissivities at wavelengths (λ) in the range 500--653 nm, the enthalpies, and heat capacities of the liquid phases of cobalt, titanium, and zirconium. Emissivity measurements were carried out by means of electromagnetic levitation at the solid-to-liquid transition with a partial-radiation pyrometer operating at λ = 547 and 650 nm. Considering the sensitivity of the optical properties to surface impurities, investigations on the surfaces of several titanium and zirconium samples by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) were performed that confirmed a nitrogen- and oxygen-free process atmosphere during the measurements. Liquid phase normal emissivities obtained were var-epsilon n,547 = 0.365 and var-epsilon n,650 = 0.331 for cobalt, var-epsilon n,547 = 0.409 and var-epsilon n,650 = 0.393 for titanium, and var-epsilon n,547 = 0.365 and var-epsilon n,650 = 0.355 for zirconium. Enthalpy measurements on the liquid metals were carried out by means of levitation-drop calorimetry in the range 1591--2159 K for cobalt, 1847--2430 K for titanium, and 2025--2897 K for zirconium. The resulting heat capacities (values in J·mol -1 ·K -1 ) obtained were 42.78 for cobalt, 43.79 for titanium, and 39.81 for zirconium

  18. Primary sources of selected POPs: regional and global scale emission inventories

    Energy Technology Data Exchange (ETDEWEB)

    Breivik, Knut; Alcock, Ruth; Li Yifan; Bailey, Robert E.; Fiedler, Heidelore; Pacyna, Jozef M

    2004-03-01

    During the last decade, a number of studies have been devoted to the sources and emissions of Persistent Organic Pollutants (POPs) at regional and global scales. While significant improvements in knowledge have been achieved for some pesticides, the quantitative understanding of the emission processes and emission patterns for 'non-pesticide' POPs are still considered limited. The key issues remaining for the non-pesticide POPs are in part determined by their general source classification. For industrial chemicals, such as the polychlorinated biphenyls (PCBs), there is considerable uncertainty with respect to the relative importance of atmospheric emissions from various source categories. For PCBs, temperature is discussed as a potential key factor influencing atmospheric emission levels and patterns. When it comes to the unintentional by-products of combustion and industrial processes (PCDD/Fs), there is still a large uncertainty with respect to the relative contribution of emissions from unregulated sources such as backyard barrel burning that requires further consideration and characterisation. For hexachlorobenzene (HCB), the relative importance of primary and secondary atmospheric emissions in controlling current atmospheric concentrations remains one of the key uncertainties. While these and other issues may remain unresolved, knowledge concerning the emissions of POPs is a prerequisite for any attempt to understand and predict the distribution and fate of these chemicals on a regional and global scale as well as to efficiently minimise future environmental burdens. - Knowledge of primary emissions is a prerequisite for understanding and predicting POPs on a regional/global scale.

  19. Primary sources of selected POPs: regional and global scale emission inventories

    International Nuclear Information System (INIS)

    Breivik, Knut; Alcock, Ruth; Li Yifan; Bailey, Robert E.; Fiedler, Heidelore; Pacyna, Jozef M.

    2004-01-01

    During the last decade, a number of studies have been devoted to the sources and emissions of Persistent Organic Pollutants (POPs) at regional and global scales. While significant improvements in knowledge have been achieved for some pesticides, the quantitative understanding of the emission processes and emission patterns for 'non-pesticide' POPs are still considered limited. The key issues remaining for the non-pesticide POPs are in part determined by their general source classification. For industrial chemicals, such as the polychlorinated biphenyls (PCBs), there is considerable uncertainty with respect to the relative importance of atmospheric emissions from various source categories. For PCBs, temperature is discussed as a potential key factor influencing atmospheric emission levels and patterns. When it comes to the unintentional by-products of combustion and industrial processes (PCDD/Fs), there is still a large uncertainty with respect to the relative contribution of emissions from unregulated sources such as backyard barrel burning that requires further consideration and characterisation. For hexachlorobenzene (HCB), the relative importance of primary and secondary atmospheric emissions in controlling current atmospheric concentrations remains one of the key uncertainties. While these and other issues may remain unresolved, knowledge concerning the emissions of POPs is a prerequisite for any attempt to understand and predict the distribution and fate of these chemicals on a regional and global scale as well as to efficiently minimise future environmental burdens. - Knowledge of primary emissions is a prerequisite for understanding and predicting POPs on a regional/global scale

  20. The recombination mechanisms leading to amplified spontaneous emission at the true-green wavelength in CH3NH3PbBr3 perovskites

    Science.gov (United States)

    Priante, D.; Dursun, I.; Alias, M. S.; Shi, D.; Melnikov, V. A.; Ng, T. K.; Mohammed, O. F.; Bakr, O. M.; Ooi, B. S.

    2015-02-01

    We investigated the mechanisms of radiative recombination in a CH3NH3PbBr3 hybrid perovskite material using low-temperature, power-dependent (77 K), and temperature-dependent photoluminescence (PL) measurements. Two bound-excitonic radiative transitions related to grain size inhomogeneity were identified. Both transitions led to PL spectra broadening as a result of concurrent blue and red shifts of these excitonic peaks. The red-shifted bound-excitonic peak dominated at high PL excitation led to a true-green wavelength of 553 nm for CH3NH3PbBr3 powders that are encapsulated in polydimethylsiloxane. Amplified spontaneous emission was eventually achieved for an excitation threshold energy of approximately 350 μJ/cm2. Our results provide a platform for potential extension towards a true-green light-emitting device for solid-state lighting and display applications.

  1. The recombination mechanisms leading to amplified spontaneous emission at the true-green wavelength in CH3NH3PbBr3 perovskites

    KAUST Repository

    Priante, Davide

    2015-02-23

    We investigated the mechanisms of radiative recombination in a CH3NH3PbBr3 hybrid perovskite material using low-temperature, power-dependent (77K), and temperature-dependent photoluminescence (PL) measurements. Two bound-excitonic radiative transitions related to grain size inhomogeneity were identified. Both transitions led to PL spectra broadening as a result of concurrent blue and red shifts of these excitonic peaks. The red-shifted bound-excitonic peak dominated at high PL excitation led to a true-green wavelength of 553nm for CH3NH3PbBr3 powders that are encapsulated in polydimethylsiloxane. Amplified spontaneous emission was eventually achieved for an excitation threshold energy of approximately 350μJ/cm2. Our results provide a platform for potential extension towards a true-green light-emitting device for solid-state lighting and display applications.

  2. Extended wavelength anisotropy resolved multidimensional emission spectroscopy (ARMES) measurements: better filters, validation standards, and Rayleigh scatter removal methods

    Science.gov (United States)

    Casamayou-Boucau, Yannick; Ryder, Alan G.

    2017-09-01

    Anisotropy resolved multidimensional emission spectroscopy (ARMES) provides valuable insights into multi-fluorophore proteins (Groza et al 2015 Anal. Chim. Acta 886 133-42). Fluorescence anisotropy adds to the multidimensional fluorescence dataset information about the physical size of the fluorophores and/or the rigidity of the surrounding micro-environment. The first ARMES studies used standard thin film polarizers (TFP) that had negligible transmission between 250 and 290 nm, preventing accurate measurement of intrinsic protein fluorescence from tyrosine and tryptophan. Replacing TFP with pairs of broadband wire grid polarizers enabled standard fluorescence spectrometers to accurately measure anisotropies between 250 and 300 nm, which was validated with solutions of perylene in the UV and Erythrosin B and Phloxine B in the visible. In all cases, anisotropies were accurate to better than ±1% when compared to literature measurements made with Glan Thompson or TFP polarizers. Better dual wire grid polarizer UV transmittance and the use of excitation-emission matrix measurements for ARMES required complete Rayleigh scatter elimination. This was achieved by chemometric modelling rather than classical interpolation, which enabled the acquisition of pure anisotropy patterns over wider spectral ranges. In combination, these three improvements permit the accurate implementation of ARMES for studying intrinsic protein fluorescence.

  3. 76 FR 70833 - National Emission Standards for Hazardous Air Pollutant Emissions for Primary Lead Processing

    Science.gov (United States)

    2011-11-15

    ... INFORMATION: For specific information regarding the modeling methodology, contact Dr. Michael Stewart, Office... there is a malfunction, the emission limitation is still enforceable through injunctive relief. While... (GEP) stack height of 330 feet (as was done in the SIP and in modeling submitted by the Doe Run Company...

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

    Science.gov (United States)

    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.

  5. Multi-wavelength emission from a single InGaN/GaN nanorod analyzed by cathodoluminescence hyperspectral imaging

    KAUST Repository

    Kusch, Gunnar

    2018-01-23

    Multiple luminescence peaks emitted by a single InGaN/GaN quantum-well(QW) nanorod, extending from the blue to the red, were analysed by a combination of electron microscope based imaging techniques. Utilizing the capability of cathodoluminescence hyperspectral imaging it was possible to investigate spatial variations in the luminescence properties on a nanoscale. The high optical quality of a single GaN nanorod was demonstrated, evidenced by a narrow band-edge peak and the absence of any luminescence associated with the yellow defect band. Additionally two spatially confined broad luminescence bands were observed, consisting of multiple peaks ranging from 395 nm to 480 nm and 490 nm to 650 nm. The lower energy band originates from broad c-plane QWs located at the apex of the nanorod and the higher energy band from the semipolar QWs on the pyramidal nanorod tip. Comparing the experimentally observed peak positions with peak positions obtained from plane wave modelling and 3D finite difference time domain(FDTD) modelling shows modulation of the nanorod luminescence by cavity modes. By studying the influence of these modes we demonstrate that this can be exploited as an additional parameter in engineering the emission profile of LEDs.

  6. Multi-band emission in a wide wavelength range from tin oxide/Au nanocomposites grown on porous anodic alumina substrate (AAO)

    International Nuclear Information System (INIS)

    Norek, Małgorzata; Michalska-Domańska, Marta; Stępniowski, Wojciech J.; Ayala, Israel; Bombalska, Aneta; Budner, Bogusław

    2013-01-01

    The photoluminescence (PL) properties of tin oxide nanostructures are investigated. Three samples of different morphology, induced by deposition process and various geometrical features of nanoporous anodic aluminum oxide (AAO) substrate, are analyzed. X-ray photoelectronic spectroscopy (XPS) analysis reveals the presence of two forms of tin oxide on the surface of all studied samples: SnO and SnO 2 . The former form is typical for reduced surface with bridging oxygen atoms and every other row of in-plane oxygen atoms removed. The oxygen defects give rise to a strong emission in visible region. Two intense PL peaks are observed centered at about 540 (band I) and 620 (band II) nm. The origin of these bands was ascribed to the recombination of electrons from the conduction band (band I) and shallow traps levels (band II) to the surface oxygen vacancy levels. Upon deposition of Au nanoparticles on the top of tin oxide nanostructures the emission at 540 and 620 nm disappears and a new band (band III) occurs in the range >760 nm. The PL mechanism operating in the studied systems is discussed. The tin oxide/Au nanocomposites can be used as efficient multi-band light emitters in a wide (from visible to near infrared) wavelength range.

  7. Primary and Aggregate Size Distributions of PM in Tail Pipe Emissions form Diesel Engines

    Science.gov (United States)

    Arai, Masataka; Amagai, Kenji; Nakaji, Takayuki; Hayashi, Shinji

    Particulate matter (PM) emission exhausted from diesel engine should be reduced to keep the clean air environment. PM emission was considered that it consisted of coarse and aggregate particles, and nuclei-mode particles of which diameter was less than 50nm. However the detail characteristics about these particles of the PM were still unknown and they were needed for more physically accurate measurement and more effective reduction of exhaust PM emission. In this study, the size distributions of solid particles in PM emission were reported. PMs in the tail-pipe emission were sampled from three type diesel engines. Sampled PM was chemically treated to separate the solid carbon fraction from other fractions such as soluble organic fraction (SOF). The electron microscopic and optical-manual size measurement procedures were used to determine the size distribution of primary particles those were formed through coagulation process from nuclei-mode particles and consisted in aggregate particles. The centrifugal sedimentation method was applied to measure the Stokes diameter of dry-soot. Aerodynamic diameters of nano and aggregate particles were measured with scanning mobility particle sizer (SMPS). The peak aggregate diameters detected by SMPS were fallen in the same size regime as the Stokes diameter of dry-soot. Both of primary and Stokes diameters of dry-soot decreased with increases of engine speed and excess air ratio. Also, the effects of fuel properties and engine types on primary and aggregate particle diameters were discussed.

  8. 76 FR 76259 - National Emissions Standards for Hazardous Air Pollutants: Primary Aluminum Reduction Plants

    Science.gov (United States)

    2011-12-06

    ... Emissions From Maleic Anhydride Plants, Ethylbenzene/Styrene Plants, Benzene Storage Vessels, Benzene...). The rule is applicable to facilities with affected sources associated with the production of aluminum... are subject to the requirements of this NESHAP: 14 primary aluminum production plants and one carbon...

  9. Fine tuning the emission wavelengths of the 7-hydroxy-1-indanone based nano-structure dyes: Near-infrared (NIR) dual emission generation with large stokes shifts

    Science.gov (United States)

    Roohi, Hossein; Alizadeh, Parvaneh

    2018-05-01

    Near-infrared (NIR) fluorescent dyes have recently gained special attention due to their applications to use as molecular probes for imaging of biological targets and sensitive determination. In this study, photophysical properties of the 7-hydroxy-1-indanone based fluorophors A1, A2, A3, B1, B2 and 3R-B2 (R = CF3, NH2, NO2 and OMe) in the gas and three solution phases were probed using TD-DFT method at PBE0/6-311++G(d,p) and M06-2X/6-311++G(d,p) levels of theory. In addition to structural and photophysical properties as well as ESIPT mechanism of all mentioned molecules, the FC and relaxed potential energy surfaces of B2 and 3R-B2 (R = CF3 and NH2) molecules were explored in gas phase and acetonitrile, cyclohexane and water solvents. It is predicted that the A1, A3 and 3R-B2 chromophores afford normal (615-670 nm) and NIR fluorescence emissions (770-940 nm; biological window) with the large Stokes shifts of >160 and >300 nm, respectively. A good aggrement was found between theoretical and experimental results. In sum, these new types of dyes may render the new approaches for the development of the most efficient NIR fluorescent probes for enhanced image contrast and optimal apparent brightness in biological applications.

  10. A national day with near zero emissions and its effect on primary and secondary pollutants

    Science.gov (United States)

    Levy, Ilan

    2013-10-01

    Traffic related air pollution is a major health concern in many countries. The potential costs and benefits of different abatement policies are usually estimated by either models, case studies or previously implemented intervention measures. Such estimations have, however, limited ability to predict the effect of a reduction in primary pollutants' emissions on secondary pollutants such as ozone, because of the nonlinear nature of the photochemical reactions. This study examines the short term effects of a drastic change in emissions on a national scale during the Jewish holiday of Day of Atonement (DA) in Israel. During the holiday nearly all anthropogenic emission sources are ceased for a period of 25 h, including all vehicles, commercial, industrial and recreational activities. DAs during the 15 years period of 1998-2012 are analyzed at three sites with respect to primary and secondary air pollutants, and in greater details for 2001. A dramatic decrease in primary pollutants emissions (83-98% in NO) causes an 8 ppbv increase in ozone at the urban core. Downwind (27 km), ozone decreases by only 5 ppbv. Nighttime O3 is shown to increase to 20 ppbv at the urban sites and 30 ppbv downwind. In spite of the striking reduction in emissions, changes in ozone are not greater than what is reported in the literature about less significant events like the ozone weekend effect. Changes in ambient pollution levels observed during DA provide some indication to the possible outcomes of a major change in anthropogenic emissions. These may be considered as the best case scenario for emissions reduction intervention measures and thus aid policy makers in evaluating potential benefits of such measures.

  11. Simultaneous detection of electronic structure changes from two elements of a bifunctional catalyst using wavelength-dispersive X-ray emission spectroscopy and in situ electrochemistry.

    Science.gov (United States)

    Gul, Sheraz; Ng, Jia Wei Desmond; Alonso-Mori, Roberto; Kern, Jan; Sokaras, Dimosthenis; Anzenberg, Eitan; Lassalle-Kaiser, Benedikt; Gorlin, Yelena; Weng, Tsu-Chien; Zwart, Petrus H; Zhang, Jin Z; Bergmann, Uwe; Yachandra, Vittal K; Jaramillo, Thomas F; Yano, Junko

    2015-04-14

    Multielectron catalytic reactions, such as water oxidation, nitrogen reduction, or hydrogen production in enzymes and inorganic catalysts often involve multimetallic clusters. In these systems, the reaction takes place between metals or metals and ligands to facilitate charge transfer, bond formation/breaking, substrate binding, and release of products. In this study, we present a method to detect X-ray emission signals from multiple elements simultaneously, which allows for the study of charge transfer and the sequential chemistry occurring between elements. Kβ X-ray emission spectroscopy (XES) probes charge and spin states of metals as well as their ligand environment. A wavelength-dispersive spectrometer based on the von Hamos geometry was used to disperse Kβ signals of multiple elements onto a position detector, enabling an XES spectrum to be measured in a single-shot mode. This overcomes the scanning needs of the scanning spectrometers, providing data free from temporal and normalization errors and therefore ideal to follow sequential chemistry at multiple sites. We have applied this method to study MnOx-based bifunctional electrocatalysts for the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). In particular, we investigated the effects of adding a secondary element, Ni, to form MnNiOx and its impact on the chemical states and catalytic activity, by tracking the redox characteristics of each element upon sweeping the electrode potential. The detection scheme we describe here is general and can be applied to time-resolved studies of materials consisting of multiple elements, to follow the dynamics of catalytic and electron transfer reactions.

  12. Excitation wavelength dependent photoluminescence emission behavior, UV induced photoluminescence enhancement and optical gap tuning of Zn0.45Cd0.55S nanoparticles for optoelectronic applications

    Science.gov (United States)

    Osman, M. A.; Abd-Elrahim, A. G.

    2018-03-01

    In the present study, we investigate the excitation wavelength (λex) dependent photoluminescence (PL) behavior in Zn0.45Cd0.55S nanoparticles. The deconvoluted PL emission bands for nanopowders and nanocolloids reveal noticeable spectral blue shift with decreasing λex accompanied by intensity enhancement. This unusual behavior is explained in terms of selective particle size distribution in nanostructures, advancing of fast ionization process at short λex; and solvation process in polar solvent. In addition, we attributed the UV-induced PL intensity enhancement and blue shift of the optical gap to the reduction in particle size by photo-corrosion process associated with the improvement in the quantum size effect; surface modification due to cross-linkage improvement of capping molecules at NPs surface; the creation of new radiative centers and the formation of photo-passivation layers from ZnSO4 and CdSO4, and photo-enhanced oxygen adsorption on Zn0.45Cd0.55S nanoparticles surface.

  13. Field trial of a dual-wavelength fluorescent emission (L.I.F.E.) instrument and the Magma White rover during the MARS2013 Mars analog mission.

    Science.gov (United States)

    Groemer, Gernot; Sattler, Birgit; Weisleitner, Klemens; Hunger, Lars; Kohstall, Christoph; Frisch, Albert; Józefowicz, Mateusz; Meszyński, Sebastian; Storrie-Lombardi, Michael; Bothe, Claudia; Boyd, Andrea; Dinkelaker, Aline; Dissertori, Markus; Fasching, David; Fischer, Monika; Föger, Daniel; Foresta, Luca; Frischauf, Norbert; Fritsch, Lukas; Fuchs, Harald; Gautsch, Christoph; Gerard, Stephan; Goetzloff, Linda; Gołebiowska, Izabella; Gorur, Paavan; Groemer, Gerhard; Groll, Petra; Haider, Christian; Haider, Olivia; Hauth, Eva; Hauth, Stefan; Hettrich, Sebastian; Jais, Wolfgang; Jones, Natalie; Taj-Eddine, Kamal; Karl, Alexander; Kauerhoff, Tilo; Khan, Muhammad Shadab; Kjeldsen, Andreas; Klauck, Jan; Losiak, Anna; Luger, Markus; Luger, Thomas; Luger, Ulrich; McArthur, Jane; Moser, Linda; Neuner, Julia; Orgel, Csilla; Ori, Gian Gabriele; Paternesi, Roberta; Peschier, Jarno; Pfeil, Isabella; Prock, Silvia; Radinger, Josef; Ragonig, Christoph; Ramirez, Barbara; Ramo, Wissam; Rampey, Mike; Sams, Arnold; Sams, Elisabeth; Sams, Sebastian; Sandu, Oana; Sans, Alejandra; Sansone, Petra; Scheer, Daniela; Schildhammer, Daniel; Scornet, Quentin; Sejkora, Nina; Soucek, Alexander; Stadler, Andrea; Stummer, Florian; Stumptner, Willibald; Taraba, Michael; Tlustos, Reinhard; Toferer, Ernst; Turetschek, Thomas; Winter, Egon; Zanella-Kux, Katja

    2014-05-01

    Abstract We have developed a portable dual-wavelength laser fluorescence spectrometer as part of a multi-instrument optical probe to characterize mineral, organic, and microbial species in extreme environments. Operating at 405 and 532 nm, the instrument was originally designed for use by human explorers to produce a laser-induced fluorescence emission (L.I.F.E.) spectral database of the mineral and organic molecules found in the microbial communities of Earth's cryosphere. Recently, our team had the opportunity to explore the strengths and limitations of the instrument when it was deployed on a remote-controlled Mars analog rover. In February 2013, the instrument was deployed on board the Magma White rover platform during the MARS2013 Mars analog field mission in the Kess Kess formation near Erfoud, Morocco. During these tests, we followed tele-science work flows pertinent to Mars surface missions in a simulated spaceflight environment. We report on the L.I.F.E. instrument setup, data processing, and performance during field trials. A pilot postmission laboratory analysis determined that rock samples acquired during the field mission exhibited a fluorescence signal from the Sun-exposed side characteristic of chlorophyll a following excitation at 405 nm. A weak fluorescence response to excitation at 532 nm may have originated from another microbial photosynthetic pigment, phycoerythrin, but final assignment awaits development of a comprehensive database of mineral and organic fluorescence spectra. No chlorophyll fluorescence signal was detected from the shaded underside of the samples.

  14. Variability in the primary emissions and secondary gas and particle formation from vehicles using bioethanol mixtures.

    Science.gov (United States)

    Gramsch, E; Papapostolou, V; Reyes, F; Vásquez, Y; Castillo, M; Oyola, P; López, G; Cádiz, A; Ferguson, S; Wolfson, M; Lawrence, J; Koutrakis, P

    2018-04-01

    Bioethanol for use in vehicles is becoming a substantial part of global energy infrastructure because it is renewable and some emissions are reduced. Carbon monoxide (CO) emissions and total hydrocarbons (THC) are reduced, but there is still controversy regarding emissions of nitrogen oxides (NO x ), aldehydes, and ethanol; this may be a concern because all these compounds are precursors of ozone and secondary organic aerosol (SOA). The amount of emissions depends on the ethanol content, but it also may depend on the engine quality and ethanol origin. Thus, a photochemical chamber was used to study secondary gas and aerosol formation from two flex-fueled vehicles using different ethanol blends in gasoline. One vehicle and the fuel used were made in the United States, and the others were made in Brazil. Primary emissions of THC, CO, carbon dioxide (CO 2 ), and nonmethane hydrocarbons (NMHC) from both vehicles decreased as the amount of ethanol in gasoline increased. NO x emissions in the U.S. and Brazilian cars decreased with ethanol content. However, emissions of THC, CO, and NO x from the Brazilian car were markedly higher than those from the U.S. car, showing high variability between vehicle technologies. In the Brazilian car, formation of secondary nitrogen dioxide (NO 2 ) and ozone (O 3 ) was lower for higher ethanol content in the fuel. In the U.S. car, NO 2 and O 3 had a small increase. Secondary particle (particulate matter [PM]) formation in the chamber decreased for both vehicles as the fraction of ethanol in fuel increased, consistent with previous studies. Secondary to primary PM ratios for pure gasoline is 11, also consistent with previous studies. In addition, the time required to form secondary PM is longer for higher ethanol blends. These results indicate that using higher ethanol blends may have a positive impact on air quality. The use of bioethanol can significantly reduce petroleum use and greenhouse gas emissions worldwide. Given the extent of

  15. Current and future emissions of primary pollutants from coal-fired power plants in Shaanxi, China.

    Science.gov (United States)

    Xu, Yong; Hu, Jianlin; Ying, Qi; Hao, Hongke; Wang, Dexiang; Zhang, Hongliang

    2017-10-01

    A high-resolution inventory of primary atmospheric pollutants from coal-fired power plants in Shaanxi in 2012 was built based on a detailed database compiled at unit level involving unit capacity, boiler size and type, commission time, corresponding control technologies, and average coal quality of 72 power plants. The pollutants included SO 2 , NO x , fine particulate matter (PM 2.5 ), inhalable particulate matter (PM 10 ), organic carbon (OC), elemental carbon (EC), carbon monoxide (CO) and non-methane volatile organic compounds (NMVOC). Emission factors for SO 2 , NO x , PM 2.5 and PM 10 were adopted from standardized official promulgation, supplemented by those from local studies. The estimated annual emissions of SO 2 , NO x , PM 2.5 , PM 10 , EC, OC, CO and NMVOC were 152.4, 314.8, 16.6, 26.4, 0.07, 0.27, 64.9 and 2.5kt, respectively. Small units (emission rates compared to medium (≥100MW and emissions were decontamination efficiency, sulfur content and ash content of coal. Weinan and Xianyang were the two cities with the highest emissions, and Guanzhong Plain had the largest emission density. Despite the projected growth of coal consumption, emissions would decrease in 2030 due to improvement in emission control technologies and combustion efficiencies. SO 2 and NO x emissions would experience significant reduction by ~81% and ~84%, respectively. PM 2.5 , PM 10 , EC and OC would be decreased by ~43% and CO and NMVOC would be reduced by ~16%. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. InP-InxGa1-xAs core-multi-shell nanowire quantum wells with tunable emission in the 1.3-1.55 μm wavelength range.

    Science.gov (United States)

    Fonseka, H A; Ameruddin, A S; Caroff, P; Tedeschi, D; De Luca, M; Mura, F; Guo, Y; Lysevych, M; Wang, F; Tan, H H; Polimeni, A; Jagadish, C

    2017-09-21

    The usability and tunability of the essential InP-InGaAs material combination in nanowire-based quantum wells (QWs) are assessed. The wurtzite phase core-multi-shell InP-InGaAs-InP nanowire QWs are characterised using cross-section transmission electron microscopy and photoluminescence measurements. The InP-InGaAs direct interface is found to be sharp while the InGaAs-InP inverted interface is more diffused, in agreement with their planar counterpart. Bright emission is observed from the single nanowires containing the QWs at room temperature, with no emission from the InP core or outer barrier. The tunability of the QW emission wavelength in the 1.3-1.55 μm communication wavelength range is demonstrated by varying the QW thickness and in the 1.3 μm range by varying the composition. The experiments are supported by simulation of the emission wavelength of the wurtzite phase InP-InGaAs QWs in the thickness range considered. The radial heterostructure is further extended to design multiple QWs with bright emission, therefore establishing the capability of this material system for nanowire based optical devices for communication applications.

  17. Wavelength standards in the infrared

    CERN Document Server

    Rao, KN

    2012-01-01

    Wavelength Standards in the Infrared is a compilation of wavelength standards suitable for use with high-resolution infrared spectrographs, including both emission and absorption standards. The book presents atomic line emission standards of argon, krypton, neon, and xenon. These atomic line emission standards are from the deliberations of Commission 14 of the International Astronomical Union, which is the recognized authority for such standards. The text also explains the techniques employed in determining spectral positions in the infrared. One of the techniques used includes the grating con

  18. Sulfur dioxide and primary carbonaceous aerosol emissions in China and India, 1996–2010

    Directory of Open Access Journals (Sweden)

    Z. Lu

    2011-09-01

    Full Text Available China and India are the two largest anthropogenic aerosol generating countries in the world. In this study, we develop a new inventory of sulfur dioxide (SO2 and primary carbonaceous aerosol (i.e., black and organic carbon, BC and OC emissions from these two countries for the period 1996–2010, using a technology-based methodology. Emissions from major anthropogenic sources and open biomass burning are included, and time-dependent trends in activity rates and emission factors are incorporated in the calculation. Year-specific monthly temporal distributions for major sectors and gridded emissions at a resolution of 0.1°×0.1° distributed by multiple year-by-year spatial proxies are also developed. In China, the interaction between economic development and environmental protection causes large temporal variations in the emission trends. From 1996 to 2000, emissions of all three species showed a decreasing trend (by 9 %–17 % due to a slowdown in economic growth, a decline in coal use in non-power sectors, and the implementation of air pollution control measures. With the economic boom after 2000, emissions from China changed dramatically. BC and OC emissions increased by 46 % and 33 % to 1.85 Tg and 4.03 Tg in 2010. SO2 emissions first increased by 61 % to 34.0 Tg in 2006, and then decreased by 9.2 % to 30.8 Tg in 2010 due to the wide application of flue-gas desulfurization (FGD equipment in power plants. Driven by the remarkable energy consumption growth and relatively lax emission controls, emissions from India increased by 70 %, 41 %, and 35 % to 8.81 Tg, 1.02 Tg, and 2.74 Tg in 2010 for SO2, BC, and OC, respectively. Monte Carlo simulations are used to quantify the emission uncertainties. The average 95 % confidence intervals (CIs of SO2, BC, and OC emissions are estimated to be −16 %–17 %, −43 %–93 %, and −43 %–80 % for China, and −15 %–16 %, −41 %–87 %, and −44 %–92

  19. Sulfur dioxide and primary carbonaceous aerosol emissions in China and India, 1996-2010

    Science.gov (United States)

    Lu, Z.; Zhang, Q.; Streets, D. G.

    2011-09-01

    China and India are the two largest anthropogenic aerosol generating countries in the world. In this study, we develop a new inventory of sulfur dioxide (SO2) and primary carbonaceous aerosol (i.e., black and organic carbon, BC and OC) emissions from these two countries for the period 1996-2010, using a technology-based methodology. Emissions from major anthropogenic sources and open biomass burning are included, and time-dependent trends in activity rates and emission factors are incorporated in the calculation. Year-specific monthly temporal distributions for major sectors and gridded emissions at a resolution of 0.1°×0.1° distributed by multiple year-by-year spatial proxies are also developed. In China, the interaction between economic development and environmental protection causes large temporal variations in the emission trends. From 1996 to 2000, emissions of all three species showed a decreasing trend (by 9 %-17 %) due to a slowdown in economic growth, a decline in coal use in non-power sectors, and the implementation of air pollution control measures. With the economic boom after 2000, emissions from China changed dramatically. BC and OC emissions increased by 46 % and 33 % to 1.85 Tg and 4.03 Tg in 2010. SO2 emissions first increased by 61 % to 34.0 Tg in 2006, and then decreased by 9.2 % to 30.8 Tg in 2010 due to the wide application of flue-gas desulfurization (FGD) equipment in power plants. Driven by the remarkable energy consumption growth and relatively lax emission controls, emissions from India increased by 70 %, 41 %, and 35 % to 8.81 Tg, 1.02 Tg, and 2.74 Tg in 2010 for SO2, BC, and OC, respectively. Monte Carlo simulations are used to quantify the emission uncertainties. The average 95 % confidence intervals (CIs) of SO2, BC, and OC emissions are estimated to be -16 %-17 %, -43 %-93 %, and -43 %-80 % for China, and -15 %-16 %, -41 %-87 %, and -44 %-92 % for India, respectively. Sulfur content, fuel use, and sulfur retention of hard coal and

  20. Global climate impacts of country-level primary carbonaceous aerosol from solid-fuel cookstove emissions

    International Nuclear Information System (INIS)

    Lacey, Forrest; Henze, Daven

    2015-01-01

    Cookstove use is globally one of the largest unregulated anthropogenic sources of primary carbonaceous aerosol. While reducing cookstove emissions through national-scale mitigation efforts has clear benefits for improving indoor and ambient air quality, and significant climate benefits from reduced green-house gas emissions, climate impacts associated with reductions to co-emitted black (BC) and organic carbonaceous aerosol are not well characterized. Here we attribute direct, indirect, semi-direct, and snow/ice albedo radiative forcing (RF) and associated global surface temperature changes to national-scale carbonaceous aerosol cookstove emissions. These results are made possible through the use of adjoint sensitivity modeling to relate direct RF and BC deposition to emissions. Semi- and indirect effects are included via global scaling factors, and bounds on these estimates are drawn from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. Absolute regional temperature potentials are used to estimate global surface temperature changes. Bounds are placed on these estimates, drawing from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. We estimate a range of 0.16 K warming to 0.28 K cooling with a central estimate of 0.06 K cooling from the removal of cookstove aerosol emissions. At the national emissions scale, countries’ impacts on global climate range from net warming (e.g., Mexico and Brazil) to net cooling, although the range of estimated impacts for all countries span zero given uncertainties in RF estimates and fuel characterization. We identify similarities and differences in the sets of countries with the highest emissions and largest cookstove temperature impacts (China, India, Nigeria, Pakistan, Bangladesh and Nepal), those with the largest temperature impact per carbon emitted (Kazakhstan, Estonia, and Mongolia), and those that would provide the

  1. Global climate impacts of country-level primary carbonaceous aerosol from solid-fuel cookstove emissions

    Science.gov (United States)

    Lacey, Forrest; Henze, Daven

    2015-11-01

    Cookstove use is globally one of the largest unregulated anthropogenic sources of primary carbonaceous aerosol. While reducing cookstove emissions through national-scale mitigation efforts has clear benefits for improving indoor and ambient air quality, and significant climate benefits from reduced green-house gas emissions, climate impacts associated with reductions to co-emitted black (BC) and organic carbonaceous aerosol are not well characterized. Here we attribute direct, indirect, semi-direct, and snow/ice albedo radiative forcing (RF) and associated global surface temperature changes to national-scale carbonaceous aerosol cookstove emissions. These results are made possible through the use of adjoint sensitivity modeling to relate direct RF and BC deposition to emissions. Semi- and indirect effects are included via global scaling factors, and bounds on these estimates are drawn from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. Absolute regional temperature potentials are used to estimate global surface temperature changes. Bounds are placed on these estimates, drawing from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. We estimate a range of 0.16 K warming to 0.28 K cooling with a central estimate of 0.06 K cooling from the removal of cookstove aerosol emissions. At the national emissions scale, countries’ impacts on global climate range from net warming (e.g., Mexico and Brazil) to net cooling, although the range of estimated impacts for all countries span zero given uncertainties in RF estimates and fuel characterization. We identify similarities and differences in the sets of countries with the highest emissions and largest cookstove temperature impacts (China, India, Nigeria, Pakistan, Bangladesh and Nepal), those with the largest temperature impact per carbon emitted (Kazakhstan, Estonia, and Mongolia), and those that would provide the

  2. A new physically-based quantification of marine isoprene and primary organic aerosol emissions

    Directory of Open Access Journals (Sweden)

    N. Meskhidze

    2009-07-01

    Full Text Available The global marine sources of organic carbon (OC are estimated here using a physically-based parameterization for the emission of marine isoprene and primary organic matter. The marine isoprene emission model incorporates new physical parameters such as light sensitivity of phytoplankton isoprene production and dynamic euphotic depth to simulate hourly marine isoprene emissions totaling 0.92 Tg C yr−1. Sensitivity studies using different schemes for the euphotic zone depth and ocean phytoplankton speciation produce the upper and the lower range of marine-isoprene emissions of 0.31 to 1.09 Tg C yr−1, respectively. Established relationships between sea spray fractionation of water-insoluble organic carbon (WIOC and chlorophyll-a concentration are used to estimate the total primary sources of marine sub- and super-micron OC of 2.9 and 19.4 Tg C yr−1, respectively. The consistent spatial and temporal resolution of the two emission types allow us, for the first time, to explore the relative contributions of sub- and super-micron organic matter and marine isoprene-derived secondary organic aerosol (SOA to the total OC fraction of marine aerosol. Using a fixed 3% mass yield for the conversion of isoprene to SOA, our emission simulations show minor (<0.2% contribution of marine isoprene to the total marine source of OC on a global scale. However, our model calculations also indicate that over the tropical oceanic regions (30° S to 30° N, marine isoprene SOA may contribute over 30% of the total monthly-averaged sub-micron OC fraction of marine aerosol. The estimated contribution of marine isoprene SOA to hourly-averaged sub-micron marine OC emission is even higher, approaching 50% over the vast regions of the oceans during the midday hours when isoprene emissions are highest. As it is widely believed that sub-micron OC has the potential to influence the cloud droplet activation of marine aerosols, our

  3. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in the detection of primary pulmonary angiosarcomas

    International Nuclear Information System (INIS)

    Krishnamurthy, Arvind; Nayak, Deepika; Ramshankar, Vijayalakshmi; Majhi, Urmila

    2015-01-01

    Angiosarcoma is a malignant vascular tumor that originates from the mesenchymal cells which have undergone angioblastic differentiation. Pulmonary angiosarcomas are invariably (>90%) metastatic tumors form primaries of the skin, bone, liver, breast, or heart. Primary pulmonary angiosarcomas are exceedingly rare, with just about 20 cases being reported in the literature. We report an additional case with a brief review of the literature of a primary pulmonary angiosarcoma in a 26-year-old lady who presented with intractable hemoptysis. In addition, we highlight the potential of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography as an important diagnostic tool in the evaluation of this tumor and thus contribute to the existing sparse literature on this fascinating yet devastating disease

  4. Distortion product otoacoustic emissions: comparison of sequential vs. simultaneous presentation of primary tones.

    Science.gov (United States)

    Kumar, U Ajith; Maruthy, Sandeep; Chandrakant, Vishwakarma

    2009-03-01

    Distortion product otoacoustic emissions are one form of evoked otoacoustic emissions. DPOAEs provide the frequency specific information about the hearing status in mid and high frequency regions. But in most screening protocols TEOAEs are preferred as it requires less time compared to DPOAE. This is because, in DPOAE each stimulus is presented one after the other and responses are analyzed. Grason and Stadler Incorporation 60 (GSI-60) offer simultaneous presentation of four sets of primary tones at a time and checks for the DPOAE. In this mode of presentation, all the pairs are presented at a time and following that response is extracted separately whereas, in sequential mode primaries are presented in orderly fashion one after the other. In this article simultaneous and sequential protocols were used to compare the Distortion product otoacoustic emission amplitude, noise floor and administration time in individuals with normal hearing and mild sensori-neural (SN) hearing loss. In simultaneous protocols four sets of primary tones (i.e. 8 tones) were presented together whereas, in sequential presentation mode one set of primary tones was presented each time. Simultaneous protocol was completed in less than half the time required for the completion of sequential protocol. Two techniques yielded similar results at frequencies above 1000 Hz only in normal hearing group. In SN hearing loss group simultaneous presentation yielded signifi cantly higher noise floors and distortion product amplitudes. This result challenges the use of simultaneous presentation technique in neonatal hearing screening programmes and on other pathologies. This discrepancy between two protocols may be due to some changes in biomechanical process in the cochlear and/or due to higher distortion/noise produced by the system during the simultaneous presentation mode.

  5. On the high characteristic temperature of an InAs/GaAs/InGaAsP QD laser with an emission wavelength of ~1.5 μm on an InP substrate

    DEFF Research Database (Denmark)

    Zubov, F.; Semenova, Elizaveta; Kulkova, Irina

    2017-01-01

    We report on a study of lasers with an emission wavelength of about 1.5 μm and high temperature stability, synthesized on an InP (001) substrate. Self-organized InAs quantum dots capped with a thin GaAs layer are used as the active region of the laser. A quaternary InGaAsP solid solution with a b......We report on a study of lasers with an emission wavelength of about 1.5 μm and high temperature stability, synthesized on an InP (001) substrate. Self-organized InAs quantum dots capped with a thin GaAs layer are used as the active region of the laser. A quaternary InGaAsP solid solution...

  6. Untangling the primary drivers of pinyon monoterpene production and emissions under predicted drought

    Science.gov (United States)

    Trowbridge, A. M.; Adams, H. D.; Breshears, D. D.; Monson, R. K.

    2012-04-01

    Climate and insect herbivory have important consequences for plant function, atmospheric composition, and the functioning of ecosystems and ecological communities. Within the last decade, pinyon-juniper woodlands throughout the southwestern U.S. have suffered large-scale mortality, especially of pinyon pine, due to drought and associated insect outbreaks. While much research has focused on the primary metabolic mechanisms underlying pinyon's sensitivity to drought, there remains a gap in our knowledge concerning how the resulting shift in carbon allocation toward plant secondary compounds, particularly monoterpenes, affects atmospheric process and ecological interactions. Monoterpenes are the principal constituents of pinyon resin. Because of their large global emission rates and effect on atmospheric chemistry, particularly ozone creation, identifying controls over emissions and sensitivities to environmental change is critical for global emission models. Furthermore, monoterpenes are known to impact insect behavior and act as defense compounds against herbivores, contributing to insect population fluctuations either directly through toxicity, or indirectly by influencing parasitism susceptibility. Pinyon mortality events are thought to be exacerbated by their susceptibility to herbivores resulting from weakened secondary chemical defenses, but the impact of current and predicted drought on the chemical defense status of pinyons and subsequent atmospheric and ecological consequences remain unknown. A field study was developed to examine the impact of seasonality and climate, particularly drought, on pinyon pine physiology and chemistry in the context of tiger moth (Lophocampa ingens) herbivory in pinyon-juniper woodlands. We demonstrate the importance of geography and seasonality, particularly mid-summer drought and late summer monsoons, in driving physiology and monoterpene concentrations and emissions. Emission rates significantly decreased throughout the summer

  7. Life cycle primary energy use and carbon emission of an eight-storey wood-framed apartment building

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, Leif; Joelsson, Anna; Sathre, Roger [Ecotechnology, Department of Engineering and Sustainable Development, Mid Sweden University, 83125 Oestersund (Sweden)

    2010-02-15

    In this study the life cycle primary energy use and carbon dioxide (CO{sub 2}) emission of an eight-storey wood-framed apartment building are analyzed. All life cycle phases are included, including acquisition and processing of materials, on-site construction, building operation, demolition and materials disposal. The calculated primary energy use includes the entire energy system chains, and carbon flows are tracked including fossil fuel emissions, process emissions, carbon stocks in building materials, and avoided fossil emissions due to biofuel substitution. The results show that building operation uses the largest share of life cycle energy use, becoming increasingly dominant as the life span of the building increases. The type of heating system strongly influences the primary energy use and CO{sub 2} emission; a biomass-based system with cogeneration of district heat and electricity achieves low primary energy use and very low CO{sub 2} emissions. Using biomass residues from the wood products chain to substitute for fossil fuels significantly reduces net CO{sub 2} emission. Excluding household tap water and electricity, a negative life cycle net CO{sub 2} emission can be achieved due to the wood-based construction materials and biomass-based energy supply system. This study shows the importance of using a life cycle perspective when evaluating primary energy and climatic impacts of buildings. (author)

  8. A high-resolution emission inventory of primary pollutants for the Huabei region, China

    Directory of Open Access Journals (Sweden)

    B. Zhao

    2012-01-01

    straw burning sectors, and large industrial point sources, which include 345 sets of power plants, iron and steel plants, cement plants, and chemical plants.

    The estimated regional NO2 emissions are about 2–3% (administrative Huabei region or 5% (larger Huabei region of the global anthropogenic NO2 emissions. We compare our inventory (IPAC-NC with the global emission inventory EDGAR-CIRCE and the Asian emission inventory INTEX-B. Except for a factor of 3 lower EC emission rate in comparison with INTEX-B, the biases of the total emissions of most primary air pollutants in Huabei estimated in our inventory, with respect to EDGAR-CIRCE and INTEX-B, generally range from −30% to +40%. Large differences up to a factor of 2–3 for local emissions in some areas (e.g. Beijing and Tianjin are found. It is recommended that the inventories based on the activity rates and emission factors for each specific year should be applied in future modeling work related to the changes in air quality and atmospheric chemistry over this region.

  9. Inhalation of primary motor vehicle emissions: Effects of urbanpopulation and land area

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, Julian D.; McKone, Thomas E.; Nazaroff, William W.

    2004-06-14

    Urban population density can influence transportation demand, as expressed through average daily vehicle-kilometers traveled per capita (VKT). In turn, changes in transportation demand influence total passenger vehicle emissions. Population density can also influence the fraction of total emissions that are inhaled by the exposed urban population. Equations are presented that describe these relationships for an idealized representation of an urban area. Using analytic solutions to these equations, we investigate the effect of three changes in urban population and urban land area (infill, sprawl, and constant-density growth) on per capita inhalation intake of primary pollutants from passenger vehicles. The magnitude of these effects depends on density-emissions elasticity ({var_epsilon}{sub e}), a normalized derivative relating change in population density to change in vehicle emissions. For example, if urban population increases, per capita intake is less with infill development than with constant-density growth if {var_epsilon}{sub e} is less than -0.5, while for {var_epsilon}{sub e} greater than -0.5 the reverse is true.

  10. Sub-wavelength plasmon laser

    Science.gov (United States)

    Bora, Mihail; Bond, Tiziana C.

    2016-04-19

    A plasmonic laser device has resonant nanocavities filled with a gain medium containing an organic dye. The resonant plasmon frequencies of the nanocavities are tuned to align with both the absorption and emission spectra of the dye. Variables in the system include the nature of the dye and the wavelength of its absorption and emission, the wavelength of the pumping radiation, and the resonance frequencies of the nanocavities. In addition the pumping frequency of the dye is selected to be close to the absorption maximum.

  11. Long-term implications of alternative light-duty vehicle technologies for global greenhouse gas emissions and primary energy demands

    International Nuclear Information System (INIS)

    Kyle, Page; Kim, Son H.

    2011-01-01

    This study assesses global light-duty vehicle (LDV) transport in the upcoming century, and the implications of vehicle technology advancement and fuel-switching on greenhouse gas emissions and primary energy demands. Five different vehicle technology scenarios are analyzed with and without a CO 2 emissions mitigation policy using the GCAM integrated assessment model: a reference internal combustion engine vehicle scenario, an advanced internal combustion engine vehicle scenario, and three alternative fuel vehicle scenarios in which all LDVs are switched to natural gas, electricity, or hydrogen by 2050. The emissions mitigation policy is a global CO 2 emissions price pathway that achieves 450 ppmv CO 2 at the end of the century with reference vehicle technologies. The scenarios demonstrate considerable emissions mitigation potential from LDV technology; with and without emissions pricing, global CO 2 concentrations in 2095 are reduced about 10 ppmv by advanced ICEV technologies and natural gas vehicles, and 25 ppmv by electric or hydrogen vehicles. All technological advances in vehicles are important for reducing the oil demands of LDV transport and their corresponding CO 2 emissions. Among advanced and alternative vehicle technologies, electricity- and hydrogen-powered vehicles are especially valuable for reducing whole-system emissions and total primary energy. - Highlights: → Alternative-fuel LDVs reduce whole-system CO 2 emissions, even without carbon pricing. → Alternative-fuel LDVs enhance the CO 2 mitigation capacity of the transportation sector. → Electric and hydrogen vehicles reduce whole-system primary energy supporting LDV transport.

  12. Quantitative evaluation of emission controls on primary and secondary organic aerosol sources during Beijing 2008 Olympics

    Directory of Open Access Journals (Sweden)

    S. Guo

    2013-08-01

    Full Text Available To assess the primary and secondary sources of fine organic aerosols after the aggressive implementation of air pollution controls during the 2008 Beijing Olympic Games, 12 h PM2.5 values were measured at an urban site at Peking University (PKU and an upwind rural site at Yufa during the CAREBEIJING-2008 (Campaigns of Air quality REsearch in BEIJING and surrounding region summer field campaign. The average PM2.5 concentrations were 72.5 ± 43.6 μg m−3 and 64.3 ± 36.2 μg m−3 (average ± standard deviation, below as the same at PKU and Yufa, respectively, showing the lowest concentrations in recent years. Combining the results from a CMB (chemical mass balance model and secondary organic aerosol (SOA tracer-yield model, five primary and four secondary fine organic aerosol sources were compared with the results from previous studies in Beijing. The relative contribution of mobile sources to PM2.5 concentrations was increased in 2008, with diesel engines contributing 16.2 ± 5.9% and 14.5 ± 4.1% and gasoline vehicles contributing 10.3 ± 8.7% and 7.9 ± 6.2% to organic carbon (OC at PKU and Yufa, respectively. Due to the implementation of emission controls, the absolute OC concentrations from primary sources were reduced during the Olympics, and the contributions from secondary formation of OC represented a larger relative source of fine organic aerosols. Compared with the non-controlled period prior to the Olympics, primary vehicle contributions were reduced by 30% at the urban site and 24% at the rural site. The reductions in coal combustion contributions were 57% at PKU and 7% at Yufa. Our results demonstrate that the emission control measures implemented in 2008 significantly alleviated the primary organic particle pollution in and around Beijing. However, additional studies are needed to provide a more comprehensive assessment of the emission control effectiveness on SOA formation.

  13. Trends in European background air reflect reductions in primary emissions of PCBs and PBDEs.

    Science.gov (United States)

    Schuster, Jasmin K; Gioia, Rosalinda; Breivik, Knut; Steinnes, Eiliv; Scheringer, Martin; Jones, Kevin C

    2010-09-01

    Data are presented for polychlorinated biphenyls (PCBs) and polybrominated diphenyls ethers (PBDEs) in passive air samplers (PAS) collected along a rural/remote latitudinal transect from southern UK to northern Norway during 2004-2008. This study is part of an ongoing campaign, using semipermeable membrane devices (SPMDs) as PAS over two year intervals since 1994. Absolute sequestered amounts of selected PCB congeners have decreased in a first order fashion between 1994-2008, with the average time of 8.4+/-3.2 years for atmospheric concentrations to decline by 50%. PCBs have continued to fractionate with latitude during this period. PBDE concentrations declined by 50% between 2000 and 2008 every 2.2+/-0.4 years. Results are discussed in terms of sources, long-range atmospheric transport, global fractionation, and clearance processes. It is concluded that the spatial and temporal trends in background European air mainly reflect the strength of primary diffusive emissions of these compounds and subsequently their ongoing declines. The direct evidence for this is similar rates of decline at all the sites; similar rates of decline for all congeners; no systematic change in the fractionation pattern since 1994. The latest results indicate a reduction in the rate of decline for PCBs (and hence in primary emissions).

  14. Cost-effective reduction of fine primary particulate matter emissions in Finland

    International Nuclear Information System (INIS)

    Karvosenoja, Niko; Klimont, Zbigniew; Tohka, Antti; Johansson, Matti

    2007-01-01

    Policies to reduce adverse health impacts of fine particulate matter (PM 2.5 ) require information on costs of abatement and associated costs. This paper explores the potential for cost-efficient control of anthropogenic primary PM 2.5 emissions in Finland. Based on a Kyoto-compliant energy projection, two emission control scenarios for 2020 were developed. 'Baseline' assumes implementation of PM controls in compliance with existing legislation. 'Reduction' assumes ambitious further reductions. Emissions for 2020 were estimated at 26 and 18.6 Gg a -1 for 'Baseline' and 'Reduction', respectively. The largest abatement potential, 3.0 Gg a -1 , was calculated for power plants and industrial combustion. The largest potential with marginal costs below 5000 Euro MG(PM 2.5 ) -1 was for domestic wood combustion, 1.7 Gg a -1 . For traffic the potential was estimated at 1.0 Gg a -1 , but was associated with high costs. The results from this paper are used in the policy-driven national integrated assessment modeling that explores cost-efficient reductions of the health impacts of PM

  15. Time-resolved characterization of primary emissions from residential wood combustion appliances.

    Science.gov (United States)

    Heringa, M F; DeCarlo, P F; Chirico, R; Lauber, A; Doberer, A; Good, J; Nussbaumer, T; Keller, A; Burtscher, H; Richard, A; Miljevic, B; Prevot, A S H; Baltensperger, U

    2012-10-16

    Primary emissions from a log wood burner and a pellet boiler were characterized by online measurements of the organic aerosol (OA) using a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) and of black carbon (BC). The OA and BC concentrations measured during the burning cycle of the log wood burner, batch wise fueled with wood logs, were highly variable and generally dominated by BC. The emissions of the pellet burner had, besides inorganic material, a high fraction of OA and a minor contribution of BC. However, during artificially induced poor burning BC was the dominating species with ∼80% of the measured mass. The elemental O:C ratio of the OA was generally found in the range of 0.2-0.5 during the startup phase or after reloading of the log wood burner. During the burnout or smoldering phase, O:C ratios increased up to 1.6-1.7, which is similar to the ratios found for the pellet boiler during stable burning conditions and higher than the O:C ratios observed for highly aged ambient OA. The organic emissions of both burners have a very similar H:C ratio at a given O:C ratio and therefore fall on the same line in the Van Krevelen diagram.

  16. Explaining global surface aerosol number concentrations in terms of primary emissions and particle formation

    Directory of Open Access Journals (Sweden)

    D. V. Spracklen

    2010-05-01

    Full Text Available We synthesised observations of total particle number (CN concentration from 36 sites around the world. We found that annual mean CN concentrations are typically 300–2000 cm−3 in the marine boundary layer and free troposphere (FT and 1000–10 000 cm−3 in the continental boundary layer (BL. Many sites exhibit pronounced seasonality with summer time concentrations a factor of 2–10 greater than wintertime concentrations. We used these CN observations to evaluate primary and secondary sources of particle number in a global aerosol microphysics model. We found that emissions of primary particles can reasonably reproduce the spatial pattern of observed CN concentration (R2=0.46 but fail to explain the observed seasonal cycle (R2=0.1. The modeled CN concentration in the FT was biased low (normalised mean bias, NMB=−88% unless a secondary source of particles was included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB=−25%. Simulated CN concentrations in the continental BL were also biased low (NMB=−74% unless the number emission of anthropogenic primary particles was increased or a mechanism that results in particle formation in the BL was included. We ran a number of simulations where we included an empirical BL nucleation mechanism either using the activation-type mechanism (nucleation rate, J, proportional to gas-phase sulfuric acid concentration to the power one or kinetic-type mechanism (J proportional to sulfuric acid to the power two with a range of nucleation coefficients. We found that the seasonal CN cycle observed at continental BL sites was better simulated by BL particle formation (R2=0.3 than by increasing the number emission from primary anthropogenic sources (R2=0.18. The nucleation constants that resulted in best overall match between model and observed CN concentrations were

  17. Explaining global surface aerosol number concentrations in terms of primary emissions and particle formation

    Science.gov (United States)

    Spracklen, D. V.; Carslaw, K. S.; Merikanto, J.; Mann, G. W.; Reddington, C. L.; Pickering, S.; Ogren, J. A.; Andrews, E.; Baltensperger, U.; Weingartner, E.; Boy, M.; Kulmala, M.; Laakso, L.; Lihavainen, H.; Kivekäs, N.; Komppula, M.; Mihalopoulos, N.; Kouvarakis, G.; Jennings, S. G.; O'Dowd, C.; Birmili, W.; Wiedensohler, A.; Weller, R.; Gras, J.; Laj, P.; Sellegri, K.; Bonn, B.; Krejci, R.; Laaksonen, A.; Hamed, A.; Minikin, A.; Harrison, R. M.; Talbot, R.; Sun, J.

    2010-05-01

    We synthesised observations of total particle number (CN) concentration from 36 sites around the world. We found that annual mean CN concentrations are typically 300-2000 cm-3 in the marine boundary layer and free troposphere (FT) and 1000-10 000 cm-3 in the continental boundary layer (BL). Many sites exhibit pronounced seasonality with summer time concentrations a factor of 2-10 greater than wintertime concentrations. We used these CN observations to evaluate primary and secondary sources of particle number in a global aerosol microphysics model. We found that emissions of primary particles can reasonably reproduce the spatial pattern of observed CN concentration (R2=0.46) but fail to explain the observed seasonal cycle (R2=0.1). The modeled CN concentration in the FT was biased low (normalised mean bias, NMB=-88%) unless a secondary source of particles was included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB=-25%). Simulated CN concentrations in the continental BL were also biased low (NMB=-74%) unless the number emission of anthropogenic primary particles was increased or a mechanism that results in particle formation in the BL was included. We ran a number of simulations where we included an empirical BL nucleation mechanism either using the activation-type mechanism (nucleation rate, J, proportional to gas-phase sulfuric acid concentration to the power one) or kinetic-type mechanism (J proportional to sulfuric acid to the power two) with a range of nucleation coefficients. We found that the seasonal CN cycle observed at continental BL sites was better simulated by BL particle formation (R2=0.3) than by increasing the number emission from primary anthropogenic sources (R2=0.18). The nucleation constants that resulted in best overall match between model and observed CN concentrations were consistent with values derived in previous studies from detailed case studies at individual sites. In our model, kinetic and activation

  18. Consideration of black carbon and primary organic carbon emissions in life-cycle analysis of Greenhouse gas emissions of vehicle systems and fuels.

    Science.gov (United States)

    Cai, Hao; Wang, Michael Q

    2014-10-21

    The climate impact assessment of vehicle/fuel systems may be incomplete without considering short-lived climate forcers of black carbon (BC) and primary organic carbon (POC). We quantified life-cycle BC and POC emissions of a large variety of vehicle/fuel systems with an expanded Greenhouse gases, Regulated Emissions, and Energy use in Transportation model developed at Argonne National Laboratory. Life-cycle BC and POC emissions have small impacts on life-cycle greenhouse gas (GHG) emissions of gasoline, diesel, and other fuel vehicles, but would add 34, 16, and 16 g CO2 equivalent (CO2e)/mile, or 125, 56, and 56 g CO2e/mile with the 100 or 20 year Global Warming Potentials of BC and POC emissions, respectively, for vehicles fueled with corn stover-, willow tree-, and Brazilian sugarcane-derived ethanol, mostly due to BC- and POC-intensive biomass-fired boilers in cellulosic and sugarcane ethanol plants for steam and electricity production, biomass open burning in sugarcane fields, and diesel-powered agricultural equipment for biomass feedstock production/harvest. As a result, life-cycle GHG emission reduction potentials of these ethanol types, though still significant, are reduced from those without considering BC and POC emissions. These findings, together with a newly expanded GREET version, help quantify the previously unknown impacts of BC and POC emissions on life-cycle GHG emissions of U.S. vehicle/fuel systems.

  19. Intelligent emissions controller for substance injection in the post-primary combustion zone of fossil-fired boilers

    Science.gov (United States)

    Reifman, Jaques; Feldman, Earl E.; Wei, Thomas Y. C.; Glickert, Roger W.

    2003-01-01

    The control of emissions from fossil-fired boilers wherein an injection of substances above the primary combustion zone employs multi-layer feedforward artificial neural networks for modeling static nonlinear relationships between the distribution of injected substances into the upper region of the furnace and the emissions exiting the furnace. Multivariable nonlinear constrained optimization algorithms use the mathematical expressions from the artificial neural networks to provide the optimal substance distribution that minimizes emission levels for a given total substance injection rate. Based upon the optimal operating conditions from the optimization algorithms, the incremental substance cost per unit of emissions reduction, and the open-market price per unit of emissions reduction, the intelligent emissions controller allows for the determination of whether it is more cost-effective to achieve additional increments in emission reduction through the injection of additional substance or through the purchase of emission credits on the open market. This is of particular interest to fossil-fired electrical power plant operators. The intelligent emission controller is particularly adapted for determining the economical control of such pollutants as oxides of nitrogen (NO.sub.x) and carbon monoxide (CO) emitted by fossil-fired boilers by the selective introduction of multiple inputs of substances (such as natural gas, ammonia, oil, water-oil emulsion, coal-water slurry and/or urea, and combinations of these substances) above the primary combustion zone of fossil-fired boilers.

  20. Influence of barrier layer indium on efficiency and wavelength of InGaN multiple quantum well (MQW) with and without semi-bulk InGaN buffer for blue to green regime emission

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Saiful [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Georgia Tech-CNRS, UMI 2958, Metz (France); CEA-LETI, Minatec Campus, Grenoble (France); Sundaram, Suresh; Li, Xin; El Gmili, Youssef [Georgia Tech-CNRS, UMI 2958, Metz (France); Jamroz, Miryam E.; Robin, Ivan C. [CEA-LETI, Minatec Campus, Grenoble (France); Voss, Paul L.; Ougazzaden, Abdallah [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Georgia Tech-CNRS, UMI 2958, Metz (France); Salvestrini, Jean-Paul [Georgia Tech-CNRS, UMI 2958, Metz (France); LMOPS, University of Lorraine, EA4423, Metz (France)

    2017-08-15

    The effect of indium (In) in the barrier of InGaN/GaN multiple quantum well (MQW) has been studied for MQWs with and without semi-bulk InGaN buffer. From simulation, the optimum In content in the barrier with 3-5 nm width is 5-7% to get the optimal material quality and internal quantum efficiency (IQE) of ∝65% for 450-480 nm emission range. Simulation shows a reduction of the potential barrier due to band flattening, a more homogeneous distribution of electrons and holes in the active region and subsequently, a more radiative recombination rate with InGaN as barrier layer. Both cathodoluminescence (CL) and photoluminescence (PL) experimental results show a blue-shift of emission wavelength along with an enhancement in the emission intensity when GaN barrier is replaced with InGaN barrier, for a MQW structure both with and without the semi-bulk InGaN buffer. We attribute this blue shift to the reduced polarization mismatch and increased effective bandgap. This InGaN barrier-related improvement in IQE and efficiency droop could be useful for the realization of longer wavelength ''green-gap'' range LEDs where poor IQE and efficiency droop are more prominent due to high indium (In) in the active region. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Temporal trends and spatial variation characteristics of primary air pollutants emissions from coal-fired industrial boilers in Beijing, China

    International Nuclear Information System (INIS)

    Xue, Yifeng; Tian, Hezhong; Yan, Jing; Zhou, Zhen; Wang, Junling; Nie, Lei; Pan, Tao; Zhou, Junrui; Hua, Shenbing; Wang, Yong; Wu, Xiaoqing

    2016-01-01

    Coal-fired combustion is recognized as a significant anthropogenic source of atmospheric compounds in Beijing, causing heavy air pollution events and associated deterioration in visibility. Obtaining an accurate understanding of the temporal trends and spatial variation characteristics of emissions from coal-fired industrial combustion is essential for predicting air quality changes and evaluating the effectiveness of current control measures. In this study, an integrated emission inventory of primary air pollutants emitted from coal-fired industrial boilers in Beijing is developed for the period of 2007–2013 using a technology-based approach. Future emission trends are projected through 2030 based on current energy-related and emission control policies. Our analysis shows that there is a general downward trend in primary air pollutants emissions because of the implementation of stricter local emission standards and the promotion by the Beijing municipal government of converting from coal-fired industrial boilers to gas-fired boilers. However, the ratio of coal consumed by industrial boilers to total coal consumption has been increasing, raising concerns about the further improvement of air quality in Beijing. Our estimates indicate that the total emissions of PM 10 , PM 2.5 , SO 2 , NO x , CO and VOCs from coal-fired industrial boilers in Beijing in 2013 are approximately 19,242 t, 13,345 t, 26,615 t, 22,965 t, 63,779 t and 1406 t, respectively. Under the current environmental policies and relevant energy savings and emission control plans, it may be possible to reduce NO x and other air pollutant emissions by 94% and 90% by 2030, respectively, if advanced flue gas purification technologies are implemented and coal is replaced with natural gas in the majority of existing boilers. - Highlights: • A unit-based emission inventory of coal-fired industrial boilers is developed. • Temporal trend of historical period 2007–2013 and the future till 2030 is

  2. Seasonality of isoprenoid emissions from a primary rainforest in central Amazonia

    Directory of Open Access Journals (Sweden)

    E. G. Alves

    2016-03-01

    Full Text Available Tropical rainforests are an important source of isoprenoid and other volatile organic compound (VOC emissions to the atmosphere. The seasonal variation of these compounds is however still poorly understood. In this study, vertical profiles of mixing ratios of isoprene, total monoterpenes and total sesquiterpenes, were measured within and above the canopy, in a primary rainforest in central Amazonia, using a proton transfer reaction – mass spectrometer (PTR-MS. Fluxes of these compounds from the canopy into the atmosphere were estimated from PTR-MS measurements by using an inverse Lagrangian transport model. Measurements were carried out continuously from September 2010 to January 2011, encompassing the dry and wet seasons. Mixing ratios were higher during the dry (isoprene – 2.68 ± 0.9 ppbv, total monoterpenes – 0.67 ± 0.3 ppbv; total sesquiterpenes – 0.09 ± 0.07 ppbv than the wet season (isoprene – 1.66 ± 0.9 ppbv, total monoterpenes – 0.47 ± 0.2 ppbv; total sesquiterpenes – 0.03 ± 0.02 ppbv for all compounds. Ambient air temperature and photosynthetically active radiation (PAR behaved similarly. Daytime isoprene and total monoterpene mixing ratios were highest within the canopy, rather than near the ground or above the canopy. By comparison, daytime total sesquiterpene mixing ratios were highest near the ground. Daytime fluxes varied significantly between seasons for all compounds. The maximums for isoprene (2.53 ± 0.5 µmol m−2 h−1 and total monoterpenes (1.77 ± 0.05 µmol m−2 h−1 were observed in the late dry season, whereas the maximum for total sesquiterpenes was found during the dry-to-wet transition season (0.77 ± 0.1 µmol m−2 h−1. These flux estimates suggest that the canopy is the main source of isoprenoids emitted into the atmosphere for all seasons. However, uncertainties in turbulence parameterization near the ground could affect estimates of fluxes that come from the ground. Leaf

  3. Seasonality of isoprenoid emissions from a primary rainforest in central Amazonia

    Science.gov (United States)

    Alves, Eliane G.; Jardine, Kolby; Tota, Julio; Jardine, Angela; Yãnez-Serrano, Ana Maria; Karl, Thomas; Tavares, Julia; Nelson, Bruce; Gu, Dasa; Stavrakou, Trissevgeni; Martin, Scot; Artaxo, Paulo; Manzi, Antonio; Guenther, Alex

    2016-03-01

    Tropical rainforests are an important source of isoprenoid and other volatile organic compound (VOC) emissions to the atmosphere. The seasonal variation of these compounds is however still poorly understood. In this study, vertical profiles of mixing ratios of isoprene, total monoterpenes and total sesquiterpenes, were measured within and above the canopy, in a primary rainforest in central Amazonia, using a proton transfer reaction - mass spectrometer (PTR-MS). Fluxes of these compounds from the canopy into the atmosphere were estimated from PTR-MS measurements by using an inverse Lagrangian transport model. Measurements were carried out continuously from September 2010 to January 2011, encompassing the dry and wet seasons. Mixing ratios were higher during the dry (isoprene - 2.68 ± 0.9 ppbv, total monoterpenes - 0.67 ± 0.3 ppbv; total sesquiterpenes - 0.09 ± 0.07 ppbv) than the wet season (isoprene - 1.66 ± 0.9 ppbv, total monoterpenes - 0.47 ± 0.2 ppbv; total sesquiterpenes - 0.03 ± 0.02 ppbv) for all compounds. Ambient air temperature and photosynthetically active radiation (PAR) behaved similarly. Daytime isoprene and total monoterpene mixing ratios were highest within the canopy, rather than near the ground or above the canopy. By comparison, daytime total sesquiterpene mixing ratios were highest near the ground. Daytime fluxes varied significantly between seasons for all compounds. The maximums for isoprene (2.53 ± 0.5 µmol m-2 h-1) and total monoterpenes (1.77 ± 0.05 µmol m-2 h-1) were observed in the late dry season, whereas the maximum for total sesquiterpenes was found during the dry-to-wet transition season (0.77 ± 0.1 µmol m-2 h-1). These flux estimates suggest that the canopy is the main source of isoprenoids emitted into the atmosphere for all seasons. However, uncertainties in turbulence parameterization near the ground could affect estimates of fluxes that come from the ground. Leaf phenology seemed to be an important driver of seasonal

  4. Multi-directional emission and detection of spin waves propagating in yttrium iron garnet with wavelengths down to about 100 nm

    Science.gov (United States)

    Maendl, Stefan; Grundler, Dirk

    2018-05-01

    We performed broadband spin-wave spectroscopy on 200 nm thick yttrium iron garnet containing arrays of partially embedded magnetic nanodisks. Using integrated coplanar waveguides (CPWs), we studied the excitation and transmission of spin waves depending on the presence of nanomagnet arrays of different lateral extensions. By means of the grating coupler effect, we excited spin waves propagating in multiple lateral directions with wavelengths down to 111 nm. They exhibited group velocities of up to 1 km/s. Detection of such short-wavelength spin waves was possible only in symmetrically designed emitter/detector configurations, not with a bare CPW. We report spin waves propagating between grating couplers under oblique angles exhibiting a wave vector component parallel to the CPW. The effective propagation distance amounted to about 80 μm. Such transmission signals were not addressed before and substantiate the versatility of the grating coupler effect for implementing nanomagnonic circuits.

  5. Wavelength converter technology

    DEFF Research Database (Denmark)

    Kloch, Allan; Hansen, Peter Bukhave; Poulsen, Henrik Nørskov

    1999-01-01

    Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on all-optical wavelength converter types based on semiconductor optical amplifiers.......Wavelength conversion is important since it ensures full flexibility of the WDM network layer. Progress in optical wavelength converter technology is reviewed with emphasis on all-optical wavelength converter types based on semiconductor optical amplifiers....

  6. 18F-fluorodeoxyglucose positron emission tomography in colorectal cancer: value in primary staging and follow-up

    International Nuclear Information System (INIS)

    Joerg, L.; Heinisch, M.; Rechberger, E.; Kurz, F.; Klug, R.; Aufschnaiter, M; Hammer, J.; Langsteger, W.

    2002-01-01

    Positron emission tomography using 18 F-fluorodeoxyglucose (FDG-PET) is a encouraging imaging techniques allowing a highly sensitive whole-body search for malignant foci detected by their increased glucose metabolism compared with benign tissues. Several studies are now available that indicate its added value for diagnosis and staging of colorectal cancer. In all, patient management seems to be changed in 20-30 % of patients who undergo fluorodeoxyglucose positron emission tomography in addition to standard staging procedures. Fluorodeoxyglucose positron emission tomography is also useful in monitoring radiation therapy and chemotherapy. Regarding preoperative staging of primary colorectal cancer the literature is very limited. (author)

  7. Wavelength and coherence effects on the growth mechanism of silicon nanopillars and their use in the modification of spontaneous lifetime emission of BODIPY dye molecules

    Energy Technology Data Exchange (ETDEWEB)

    Acikgoz, Sabriye [Bogazici University, Department of Physics, Istanbul (Turkey); Karamanoglu Mehmetbey University, Department of Material Science and Engineering, Karaman (Turkey); Bilen, Bukem; Saygili, Asli C.; Aktas, Gulen; Inci, Mehmet Naci [Bogazici University, Department of Physics, Istanbul (Turkey); Sanyal, Amitav [Bogazici University, Department of Chemistry, Istanbul (Turkey)

    2012-09-15

    Silicon nanopillars are grown by an electrochemical anodization of p-type silicon wafers at low current densities in a hydrofluoric acid solution. CW, white light, and various UV pulsed lasers are employed as illumination sources in sample preparation to study wavelength and coherence effects on the growth mechanism of the nanopillars. Coherence is observed to be the foundation of regularity in obtaining conical shapes. The pillar size is found to be almost linearly proportional to the employed illumination wavelength during their growth. BODIPY dye molecules are chemically attached to these silicon nanopillars and the radiative decay rates are investigated by means of a time-resolved fluorescence experiment. The decay rate of the dye molecules embedded in the vicinity of various size pillar tips is significantly affected due to different apex angles of the conical nature. It is demonstrated that the pillar size and the separation between pillars can be adjusted if one uses a coherent light source with an appropriate wavelength during the course of fabrication process. Since change in the decay rate is due to tips of the pillars only, separation of a few micrometers between pillar tips allows one to directly monitor a dye, which is embedded to the tip of a single nanopillar, via a confocal microscopic method for the spontaneous lifetime measurements, without having needed to any extra efforts for an in situ imaging process. It is observed that as the pillar size gets smaller, the inhibition in the spontaneous lifetime of BODIPY is more pronounced. In addition, a more regular pillar structure yields nonvarying decay rates of the dye molecules throughout the silicon sample. (orig.)

  8. Open burning of rice, corn and wheat straws: primary emissions, photochemical aging, and secondary organic aerosol formation

    Science.gov (United States)

    Fang, Zheng; Deng, Wei; Zhang, Yanli; Ding, Xiang; Tang, Mingjin; Liu, Tengyu; Hu, Qihou; Zhu, Ming; Wang, Zhaoyi; Yang, Weiqiang; Huang, Zhonghui; Song, Wei; Bi, Xinhui; Chen, Jianmin; Sun, Yele; George, Christian; Wang, Xinming

    2017-12-01

    Agricultural residues are among the most abundant biomass burned globally, especially in China. However, there is little information on primary emissions and photochemical evolution of agricultural residue burning. In this study, indoor chamber experiments were conducted to investigate primary emissions from open burning of rice, corn and wheat straws and their photochemical aging as well. Emission factors of NOx, NH3, SO2, 67 non-methane hydrocarbons (NMHCs), particulate matter (PM), organic aerosol (OA) and black carbon (BC) under ambient dilution conditions were determined. Olefins accounted for > 50 % of the total speciated NMHCs emission (2.47 to 5.04 g kg-1), indicating high ozone formation potential of straw burning emissions. Emission factors of PM (3.73 to 6.36 g kg-1) and primary organic carbon (POC, 2.05 to 4.11 gC kg-1), measured at dilution ratios of 1300 to 4000, were lower than those reported in previous studies at low dilution ratios, probably due to the evaporation of semi-volatile organic compounds under high dilution conditions. After photochemical aging with an OH exposure range of (1.97-4.97) × 1010 molecule cm-3 s in the chamber, large amounts of secondary organic aerosol (SOA) were produced with OA mass enhancement ratios (the mass ratio of total OA to primary OA) of 2.4-7.6. The 20 known precursors could only explain 5.0-27.3 % of the observed SOA mass, suggesting that the major precursors of SOA formed from open straw burning remain unidentified. Aerosol mass spectrometry (AMS) signaled that the aged OA contained less hydrocarbons but more oxygen- and nitrogen-containing compounds than primary OA, and carbon oxidation state (OSc) calculated with AMS resolved O / C and H / C ratios increased linearly (p < 0.001) with OH exposure with quite similar slopes.

  9. One-pot and ultrafast synthesis of nitrogen and phosphorus co-doped carbon dots possessing bright dual wavelength fluorescence emission

    Science.gov (United States)

    Sun, Xiangcheng; Brückner, Christian; Lei, Yu

    2015-10-01

    Very brief microwave heating of aniline, ethylene diamine, and phosphoric acid in water at ambient pressure generated nitrogen and phosphorus co-doped carbon dots (N,P-CDs) that exhibit bright dual blue (centred at 450 nm; 51% quantum yield) and green (centred at 510 nm, 38% quantum yield) fluorescence emission bands. The N,P-CDs were characterized using TEM, XRD, XPS, IR, UV-vis, and fluorescence spectroscopy, demonstrating their partially crystalline carbon, partially amorphous structures, and the incorporation of O, N, and P into the carbogenic scaffold. The N,P-CDs demonstrated excitation-dependent and nearly pH-independent emission properties. The unique dual emission properties lay the foundation for the use of N,P-CDs in ratiometric sensing applications.Very brief microwave heating of aniline, ethylene diamine, and phosphoric acid in water at ambient pressure generated nitrogen and phosphorus co-doped carbon dots (N,P-CDs) that exhibit bright dual blue (centred at 450 nm; 51% quantum yield) and green (centred at 510 nm, 38% quantum yield) fluorescence emission bands. The N,P-CDs were characterized using TEM, XRD, XPS, IR, UV-vis, and fluorescence spectroscopy, demonstrating their partially crystalline carbon, partially amorphous structures, and the incorporation of O, N, and P into the carbogenic scaffold. The N,P-CDs demonstrated excitation-dependent and nearly pH-independent emission properties. The unique dual emission properties lay the foundation for the use of N,P-CDs in ratiometric sensing applications. Electronic supplementary information (ESI) available: Detailed experimental section, XRD, FTIR, explosive sensing and the applications results. See DOI: 10.1039/c5nr05549k

  10. Shifting primary energy source and NOx emission location with plug-in hybrid vehicles

    Science.gov (United States)

    Karman, Deniz

    2011-06-01

    Plug-in hybrid vehicles (PHEVs) present an interesting technological opportunity for using non-fossil primary energy in light duty passenger vehicles, with the associated potential for reducing air pollutant and greenhouse gas emissions, to the extent that the electric power grid is fed by non-fossil sources. This perspective, accompanying the article by Thompson et al (2011) in this issue, will touch on two other studies that are directly related: the Argonne study (Elgowainy et al 2010) and a PhD thesis from Utrecht (van Vliet 2010). Thompson et al (2011) have examined air quality effects in a case where the grid is predominantly fossil fed. They estimate a reduction of 7.42 tons/day of NOx from motor vehicles as a result of substituting electric VMTs for 20% of the light duty gasoline vehicle miles traveled. To estimate the impact of this reduction on air quality they also consider the increases in NOx emissions due to the increased load on electricity generating units. The NOx emission increases are estimated as 4.0, 5.5 and 6.3 tons for the Convenience, Battery and Night charging scenarios respectively. The net reductions are thus in the 1.1-3.4 tons/day range. The air quality modelling results presented show that the air quality impact from a ground-level ozone perspective is favorable overall, and while the effect is stronger in some localities, the difference between the three scenarios is small. This is quite significant and suggests that localization of the NOx emissions to point sources has a more pronounced effect than the absolute reductions achieved. Furthermore it demonstrates that localization of NOx emissions to electricity generating units by using PHEVs in vehicle traffic has beneficial effects for air quality not only by minimizing direct human exposure to motor vehicle emissions, but also due to reduced exposure to secondary pollutants (i.e. ozone). In an electric power grid with a smaller share of fossil fired generating units, the beneficial

  11. Using otoacoustic emissions to screen young children for hearing loss in primary care settings.

    Science.gov (United States)

    Foust, Terry; Eiserman, William; Shisler, Lenore; Geroso, Amy

    2013-07-01

    Otoacoustic emissions (OAE) technology, used widely in newborn hearing screening programs and validated by professional organizations as a reliable and objective tool, is beginning to be recognized as superior to subjective methods when screening young children in a variety of settings. This study examines the efficacy of integrating OAE hearing screening into services routinely provided in health care settings. Three federally funded clinics serving low-income and uninsured people in a metropolitan area participated in the 10-month study. Subjects included 846 children (842 in the target population children did not pass the initial screening. Audiological evaluation was sought for children not passing a subsequent OAE screening. Of the 846 children screened, 814 (96%) ultimately passed the screening or audiological assessment and 29 (3%) exited the study. Three children (1 was 5) were identified with permanent hearing loss. The rate of identification of permanent hearing loss in this study is similar to findings from a study of OAE screening in early childhood educational settings. OAE screening holds the potential for being an effective method for helping to identify young children with permanent hearing loss in primary care settings.

  12. Vibrational motions associated with primary processes in bacteriorhodopsin studied by coherent infrared emission spectroscopy.

    Science.gov (United States)

    Groma, Géza I; Colonna, Anne; Martin, Jean-Louis; Vos, Marten H

    2011-03-16

    The primary energetic processes driving the functional proton pump of bacteriorhodopsin take place in the form of complex molecular dynamic events after excitation of the retinal chromophore into the Franck-Condon state. These early events include a strong electronic polarization, skeletal stretching, and all-trans-to-13-cis isomerization upon formation of the J intermediate. The effectiveness of the photoreaction is ensured by a conical intersection between the electronic excited and ground states, providing highly nonadiabatic coupling to nuclear motions. Here, we study real-time vibrational coherences associated with these motions by analyzing light-induced infrared emission from oriented purple membranes in the 750-1400 cm(-)(1) region. The experimental technique applied is based on second-order femtosecond difference frequency generation on macroscopically ordered samples that also yield information on phase and direction of the underlying motions. Concerted use of several analysis methods resulted in the isolation and characterization of seven different vibrational modes, assigned as C-C stretches, out-of-plane methyl rocks, and hydrogen out-of-plane wags, whereas no in-plane H rock was found. Based on their lifetimes and several other criteria, we deduce that the majority of the observed modes take place on the potential energy surface of the excited electronic state. In particular, the direction sensitivity provides experimental evidence for large intermediate distortions of the retinal plane during the excited-state isomerization process. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  13. Primary gas- and particle-phase emissions and secondary organic aerosol production from gasoline and diesel off-road engines.

    Science.gov (United States)

    Gordon, Timothy D; Tkacik, Daniel S; Presto, Albert A; Zhang, Mang; Jathar, Shantanu H; Nguyen, Ngoc T; Massetti, John; Truong, Tin; Cicero-Fernandez, Pablo; Maddox, Christine; Rieger, Paul; Chattopadhyay, Sulekha; Maldonado, Hector; Maricq, M Matti; Robinson, Allen L

    2013-12-17

    Dilution and smog chamber experiments were performed to characterize the primary emissions and secondary organic aerosol (SOA) formation from gasoline and diesel small off-road engines (SOREs). These engines are high emitters of primary gas- and particle-phase pollutants relative to their fuel consumption. Two- and 4-stroke gasoline SOREs emit much more (up to 3 orders of magnitude more) nonmethane organic gases (NMOGs), primary PM and organic carbon than newer on-road gasoline vehicles (per kg of fuel burned). The primary emissions from a diesel transportation refrigeration unit were similar to those of older, uncontrolled diesel engines used in on-road vehicles (e.g., premodel year 2007 heavy-duty diesel trucks). Two-strokes emitted the largest fractional (and absolute) amount of SOA precursors compared to diesel and 4-stroke gasoline SOREs; however, 35-80% of the NMOG emissions from the engines could not be speciated using traditional gas chromatography or high-performance liquid chromatography. After 3 h of photo-oxidation in a smog chamber, dilute emissions from both 2- and 4-stroke gasoline SOREs produced large amounts of semivolatile SOA. The effective SOA yield (defined as the ratio of SOA mass to estimated mass of reacted precursors) was 2-4% for 2- and 4-stroke SOREs, which is comparable to yields from dilute exhaust from older passenger cars and unburned gasoline. This suggests that much of the SOA production was due to unburned fuel and/or lubrication oil. The total PM contribution of different mobile source categories to the ambient PM burden was calculated by combining primary emission, SOA production and fuel consumption data. Relative to their fuel consumption, SOREs are disproportionately high total PM sources; however, the vastly greater fuel consumption of on-road vehicles renders them (on-road vehicles) the dominant mobile source of ambient PM in the Los Angeles area.

  14. Primary emissions and secondary aerosol production potential from woodstoves for residential heating: Influence of the stove technology and combustion efficiency

    Science.gov (United States)

    Bertrand, Amelie; Stefenelli, Giulia; Bruns, Emily A.; Pieber, Simone M.; Temime-Roussel, Brice; Slowik, Jay G.; Prévôt, André S. H.; Wortham, Henri; El Haddad, Imad; Marchand, Nicolas

    2017-11-01

    To reduce the influence of biomass burning on air quality, consumers are encouraged to replace their old woodstove with new and cleaner appliances. While their primary emissions have been extensively investigated, the impact of atmospheric aging on these emissions, including secondary organic aerosol (SOA) formation, remains unknown. Here, using an atmospheric smog chamber, we aim at understanding the chemical nature and quantify the emission factors of the primary organic aerosols (POA) from three types of appliances for residential heating, and to assess the influence of aging thereon. Two, old and modern, logwood stoves and one pellet burner were operated under typical conditions. Emissions from an entire burning cycle (past the start-up operation) were injected, including the smoldering and flaming phases, resulting in highly variable emission factors. The stoves emitted a significant fraction of POA (up to 80%) and black carbon. After ageing, the total mass concentration of organic aerosol (OA) increased on average by a factor of 5. For the pellet stove, flaming conditions were maintained throughout the combustion. The aerosol was dominated by black carbon (over 90% of the primary emission) and amounted to the same quantity of primary aerosol emitted by the old logwood stove. However, after ageing, the OA mass was increased by a factor of 1.7 only, thus rendering OA emissions by the pellet stove almost negligible compared to the other two stoves tested. Therefore, the pellet stove was the most reliable and least polluting appliance out of the three stoves tested. The spectral signatures of the POA and aged emissions by a High Resolution - Time of Flight - Aerosol Mass Spectrometer (Electron Ionization (EI) at 70 eV) were also investigated. The m/z 44 (CO2+) and high molecular weight fragments (m/z 115 (C9H7+), 137 (C8H9O2+), 167 (C9H11O3+) and 181 (C9H9O4+, C14H13+)) correlate with the modified combustion efficiency (MCE) allowing us to discriminate further

  15. Whole body 18F-deoxyglucose positron emission tomography in detecting the primary focus of metastatic cancer with an unknown primary

    International Nuclear Information System (INIS)

    Chen Yingrui; Li Weixiong; Gu Meixin; Zhan Zhiguang; Zeng Zijun

    2002-01-01

    Objective: To evaluate the value of 18 F-deoxyglucose (FDG) positron emission tomography (PET) in detecting the primary focus of metastatic cancer with an unknown primary. Methods: Twenty-nine patients with various histological types of metastases from an unknown primary after extensive conventional diagnostic work-up were studied. After intravenous 370 MBq FDG, whole body scan was made 50 minutes after injection. The results of FDG PET were compared with those of CT or MRI. Results: With FDG PET, the primary tumors were identified in 13 patients and confirmed by pathology. The corresponding detection rate was 44.8% (13/29) as compared with 27.6% (8/29) by CT or MRI. In addition, 26 metastases were discovered by FDG PET whole body imaging but only 13 were found by CT or MRI. During 2-13 months' follow-up, the mortality rates were 15.4%(2/13) and 42.9%(6/14) for patients with the primary tumor identified or unidentified. Conclusions: FDG PET is valuable in staging, selecting appropriate treatment protocol and predicting prognosis for patients suffering from metastatic cancers with an unknown primary

  16. Historical gaseous and primary aerosol emissions in the United States from 1990 to 2010

    Directory of Open Access Journals (Sweden)

    J. Xing

    2013-08-01

    Full Text Available An accurate description of emissions is crucial for model simulations to reproduce and interpret observed phenomena over extended time periods. In this study, we used an approach based on activity data to develop a consistent series of spatially resolved emissions in the United States from 1990 to 2010. The state-level anthropogenic emissions of SO2, NOx, CO, NMVOC (non-methane volatile organic compounds, NH3, PM10 and PM2.5 for a total of 49 sectors were estimated based on several long-term databases containing information about activities and emission controls. Activity data for energy-related stationary sources were derived from the State Energy Data System. Corresponding emission factors reflecting implemented emission controls were calculated back from the National Emissions Inventory (NEI for seven years (i.e., 1990, 1995, 1996, 1999, 2001, 2002 and 2005, and constrained by the AP-42 (US EPA's Compilation of Air Pollutant Emissions Factors dataset. Activity data for mobile sources including different types of highway vehicles and non-highway equipment were obtained from highway statistics reported by the Federal Highway Administration. The trends in emission factors for highway mobile source were informed by the 2011 National Transportation Statistics. Emissions for all non-energy-related sources were either scaled by the growth ratio of activity indicators or adjusted based on the NEI trends report. Because of the strengthened control efforts, particularly for the power sector and mobile sources, emissions of all pollutants except NH3 were reduced by half over the last two decades. The emission trends developed in this study are comparable with the NEI trend report and EDGAR (Emissions Database for Global Atmospheric Research data, but better constrained by trends in activity data. Reductions in SO2, NOx, CO and EC (speciation of PM2.5 by SMOKE, Sparse Matrix Operator Kernel Emissions emissions agree well with the observed changes in

  17. Enhancing carrier injection in the active region of a 280nm emission wavelength LED using graded hole and electron blocking layers

    KAUST Repository

    Janjua, Bilal

    2014-02-27

    A theoretical investigation of AlGaN UV-LED with band engineering of hole and electron blocking layers (HBL and EBL, respectively) was conducted with an aim to improve injection efficiency and reduce efficiency droop in the UV LEDs. The analysis is based on energy band diagrams, carrier distribution and recombination rates (Shockley-Reed-Hall, Auger, and radiative recombination rates) in the quantum well, under equilibrium and forward bias conditions. Electron blocking layer is based on AlaGa1-aN / Al b → cGa1-b → 1-cN / AldGa 1-dN, where a < d < b < c. A graded layer sandwiched between large bandgap AlGaN materials was found to be effective in simultaneously blocking electrons and providing polarization field enhanced carrier injection. The graded interlayer reduces polarization induced band bending and mitigates the related drawback of impediment of holes injection. Similarly on the n-side, the Alx → yGa1-x → 1-yN / AlzGa 1-zN (x < z < y) barrier acts as a hole blocking layer. The reduced carrier leakage and enhanced carrier density in the active region results in significant improvement in radiative recombination rate compared to a structure with the conventional rectangular EBL layers. The improvement in device performance comes from meticulously designing the hole and electron blocking layers to increase carrier injection efficiency. The quantum well based UV-LED was designed to emit at 280nm, which is an effective wavelength for water disinfection application.

  18. Enhancing carrier injection in the active region of a 280nm emission wavelength LED using graded hole and electron blocking layers

    KAUST Repository

    Janjua, Bilal; Ng, Tien Khee; Alyamani, Ahmed Y.; El-Desouki, Munir M.; Ooi, Boon S.

    2014-01-01

    A theoretical investigation of AlGaN UV-LED with band engineering of hole and electron blocking layers (HBL and EBL, respectively) was conducted with an aim to improve injection efficiency and reduce efficiency droop in the UV LEDs. The analysis is based on energy band diagrams, carrier distribution and recombination rates (Shockley-Reed-Hall, Auger, and radiative recombination rates) in the quantum well, under equilibrium and forward bias conditions. Electron blocking layer is based on AlaGa1-aN / Al b → cGa1-b → 1-cN / AldGa 1-dN, where a < d < b < c. A graded layer sandwiched between large bandgap AlGaN materials was found to be effective in simultaneously blocking electrons and providing polarization field enhanced carrier injection. The graded interlayer reduces polarization induced band bending and mitigates the related drawback of impediment of holes injection. Similarly on the n-side, the Alx → yGa1-x → 1-yN / AlzGa 1-zN (x < z < y) barrier acts as a hole blocking layer. The reduced carrier leakage and enhanced carrier density in the active region results in significant improvement in radiative recombination rate compared to a structure with the conventional rectangular EBL layers. The improvement in device performance comes from meticulously designing the hole and electron blocking layers to increase carrier injection efficiency. The quantum well based UV-LED was designed to emit at 280nm, which is an effective wavelength for water disinfection application.

  19. Global organic carbon emissions from primary sources from 1960 to 2009

    Science.gov (United States)

    Huang, Ye; Shen, Huizhong; Chen, Yilin; Zhong, Qirui; Chen, Han; Wang, Rong; Shen, Guofeng; Liu, Junfeng; Li, Bengang; Tao, Shu

    2015-12-01

    In an attempt to reduce uncertainty, global organic carbon (OC) emissions from a total of 70 sources were compiled at 0.1° × 0.1° resolution for 2007 (PKU-OC-2007) and country scale from 1960 to 2009. The compilation took advantage of a new fuel-consumption data product (PKU-Fuel-2007) and a series of newly published emission factors (EFOC) in developing countries. The estimated OC emissions were 32.9 Tg (24.1-50.6 Tg as interquartile range), of which less than one third was anthropogenic in origin. Uncertainty resulted primarily from variations in EFOC. Asia, Africa, and South America had high emissions mainly because of residential biomass fuel burning or wildfires. Per-person OC emission in rural areas was three times that of urban areas because of the relatively high EFOC of residential solid fuels. Temporal trend of anthropogenic OC emissions depended on rural population, and was influenced primarily by residential crop residue and agricultural waste burning. Both the OC/PM2.5 ratio and emission intensity, defined as quantity of OC emissions per unit of fuel consumption for all sources, of anthropogenic OC followed a decreasing trend, indicating continuous improvement in combustion efficiency and control measures.

  20. Evaluation of three common green building materials for ozone removal, and primary and secondary emissions of aldehydes

    Science.gov (United States)

    Gall, Elliott; Darling, Erin; Siegel, Jeffrey A.; Morrison, Glenn C.; Corsi, Richard L.

    2013-10-01

    Ozone reactions that occur on material surfaces can lead to elevated concentrations of oxidized products in the occupied space of buildings. However, there is little information on the impact of materials at full scale, especially for green building materials. Experiments were completed in a 68 m3 climate-controlled test chamber with three certified green building materials that can cover large areas in buildings: (1) recycled carpet, (2) perlite-based ceiling tile and (3) low-VOC paint and primer on recycled drywall. Ozone deposition velocity and primary and secondary emission rates of C1 to C10 saturated carbonyls were determined for two chamber mixing conditions and three values of relative humidity. A direct comparison was made between ozone deposition velocities and carbonyl yields observed for the same materials analyzed in small (10 L) chambers. Total primary carbonyl emission rates from carpet, ceiling tile and painted drywall ranged from 27 to 120 μg m-2 h-1, 13 to 40 μg m-2 h-1, 3.9 to 42 μg m-2 h-1, respectively. Ozone deposition velocity to these three materials averaged 6.1 m h-1, 2.3 m h-1 and 0.32 m h-1, respectively. Total secondary carbonyl emissions from these materials ranged from 70 to 276 μg m-2 h-1, 0 to 12 μg m-2 h-1, and 0 to 30 μg m-2 h-1, respectively. Carbonyl emissions were determined with a transient approximation, and were found to be in general agreement with those found in the literature. These results suggest that care should be taken when selecting green building materials due to potentially large differences in primary and secondary emissions.

  1. F-18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Appearance of Extramedullary Hematopoesis in a Case of Primary Myelofibrosis

    Science.gov (United States)

    Mukherjee, Anirban; Bal, Chandrasekhar; Tripathi, Madhavi; Das, Chandan Jyoti; Shamim, Shamim Ahmed

    2017-01-01

    A 44-year-old female with known primary myelofibrosis presented with shortness of breath. High Resolution Computed Tomography thorax revealed large heterogeneously enhancing extraparenchymal soft tissue density mass involving bilateral lung fields. F-18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography revealed mildly FDG avid soft tissue density mass with specks of calcification involving bilateral lung fields, liver, and spleen. Subsequent histopathologic evaluation from the right lung mass was suggestive of extramedullary hematopoesis. PMID:28533647

  2. F18 FDG positron emission tomography revelation of primary testicular lymphoma with concurrent multiple extra nodal involvement

    International Nuclear Information System (INIS)

    Vamsy, Mohana; Dattatreya, P.S.; Parakh, Megha; Dayal, Monal; Prabhakar Rao, V.V.S.

    2013-01-01

    Primary testicular lymphoma (PTL) a relatively rare disease of non-Hodgkin's lymphomas occurring with a lesser incidence of 1-2% has a propensity to occur at later ages above 50 years. PTL spreads to extra nodal sites due to deficiency of extra cellular adhesion molecules. We present detection of multiple sites of extra nodal involvement of PTL by F-18 positron emission tomography/computed tomography study aiding early detection of the dissemination thus aiding in staging and management. (author)

  3. Primary emissions and secondary organic aerosol formation from the exhaust of a flex-fuel (ethanol) vehicle

    Science.gov (United States)

    Suarez-Bertoa, R.; Zardini, A. A.; Platt, S. M.; Hellebust, S.; Pieber, S. M.; El Haddad, I.; Temime-Roussel, B.; Baltensperger, U.; Marchand, N.; Prévôt, A. S. H.; Astorga, C.

    2015-09-01

    Incentives to use biofuels may result in increasing vehicular emissions of compounds detrimental to air quality. Therefore, regulated and unregulated emissions from a Euro 5a flex-fuel vehicle, tested using E85 and E75 blends (gasoline containing 85% and 75% of ethanol (vol/vol), respectively), were investigated at 22 and -7 °C over the New European Driving Cycle, at the Vehicle Emission Laboratory at the European Commission Joint Research Centre Ispra, Italy. Vehicle exhaust was comprehensively analyzed at the tailpipe and in a dilution tunnel. A fraction of the exhaust was injected into a mobile smog chamber to study the photochemical aging of the mixture. We found that emissions from a flex-fuel vehicle, fueled by E85 and E75, led to secondary organic aerosol (SOA) formation, despite the low aromatic content of these fuel blends. Emissions of regulated and unregulated compounds, as well as emissions of black carbon (BC) and primary organic aerosol (POA) and SOA formation were higher at -7 °C. The flex-fuel unregulated emissions, mainly composed of ethanol and acetaldehyde, resulted in very high ozone formation potential and SOA, especially at low temperature (860 mg O3 km-1 and up to 38 mg C kg-1). After an OH exposure of 10 × 106 cm-3 h, SOA mass was, on average, 3 times larger than total primary particle mass emissions (BC + POA) with a high O:C ratio (up to 0.7 and 0.5 at 22 and -7 °C, respectively) typical of highly oxidized mixtures. Furthermore, high resolution organic mass spectra showed high 44/43 ratios (ratio of the ions m/z 44 and m/z 43) characteristic of low-volatility oxygenated organic aerosol. We also hypothesize that SOA formation from vehicular emissions could be due to oxidation products of ethanol and acetaldehyde, both short-chain oxygenated VOCs, e.g. methylglyoxal and acetic acid, and not only from aromatic compounds.

  4. Final report for measurement of primary particulate matter emissions from light-duty motor vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Norbeck, J. M.; Durbin, T. D.; Truex, T. J.

    1998-12-31

    This report describes the results of a particulate emissions study conducted at the University of California, Riverside, College of Engineering-Center for Environmental Research and Technology (CE-CERT) from September of 1996 to August of 1997. The goal of this program was to expand the database of particulate emissions measurements from motor vehicles to include larger numbers of representative in-use vehicles. This work was co-sponsored by the Coordinating Research Council (CRC), the South Coast Air Quality Management District (SCAQMD), and the National Renewable Energy Laboratory (NREL) and was part of a larger study of particulate emissions being conducted in several states under sponsorship by CRC. For this work, FTP particulate mass emission rates were determined for gasoline and diesel vehicles, along with the fractions of particulates below 2.5 and 10 microns aerodynamic diameter. A total of 129 gasoline-fueled vehicles and 19 diesel-fueled vehicles were tested as part of the program.

  5. Role of albedo from the Gamma-400 telescope calorimeter when recording the primary gamma emission.

    Science.gov (United States)

    Ginsburg, V. L.; Kurnosova, L. V.; Labensky, A. G.; Topchiev, N. P.; Fradkin, M. I.; Kaplin, V. A.; Kaplin, D. V.; Loginov, V. A.; Maklyaev, E. F.; Runtso, M. F.; Gorchakov, E. V.

    A calorimeter albedo emission affecting the Gamma-400 telescope operation is studied, when recording γ-quanta at energies from 10 to 1000 GeV. Methods for diminishing this impact on measuring data are proposed.

  6. Experimental investigation of aerodynamics, combustion, and emissions characteristics within the primary zone of a gas turbine combustor

    Science.gov (United States)

    Elkady, Ahmed M.

    2006-04-01

    The present work investigates pollutant emissions production, mainly nitric oxides and carbon monoxide, within the primary zone of a highly swirling combustion and methods with which to reduce their formation. A baseline study was executed at different equivalence ratios and different inlet air temperatures. The study was then extended to investigate the effects of utilizing transverse air jets on pollutant emission characteristics at different jet locations, jet mass ratio, and overall equivalence ratio as well as to investigate the jets' overall interactions with the recirculation zone. A Fourier Transform Infrared (FTIR) spectrometer was employed to measure emissions concentrations generated during combustion of Jet-A fuel in a swirl-cup assembly. Laser Doppler Velocimetry (LDV) was employed to investigate the mean flow aerodynamics within the combustor. Particle Image Velocimetry (PIV) was utilized to capture the instantaneous aerodynamic behavior of the non-reacting primary zone. Results illustrate that NOx production is a function of both the recirculation zone and the flame length. At low overall equivalence ratios, the recirculation zone is found to be the main producer of NOx. At near stoichiometric conditions, the post recirculation zone appears to be responsible for the majority of NOx produced. Results reveal the possibility of injecting air into the recirculation zone without altering flame stability to improve emission characteristics. Depending on the jet location and strength, nitric oxides as well as carbon monoxide can be reduced simultaneously. Placing the primary air jet just downstream of the fuel rich recirculation zone can lead to a significant reduction in both nitric oxides and carbon monoxide. In the case of fuel lean recirculation zone, reduction of nitric oxides can occur by placing the jets below the location of maximum radius of the recirculation zone.

  7. Cervical Lymph Node Metastases of Unknown Origin: Primary Tumor Detection with Whole-Body Positron Emission Tomography/Computed Tomography

    International Nuclear Information System (INIS)

    Nassenstein, K.; Veit-Haibach, P.; Stergar, H.; Gutzeit, A.; Freudenberg, L.; Kuehl, H.; Fischer, M.; Barkhausen, J.; Bockisch, A.; Antoch, G.

    2007-01-01

    Background: Identification of primary tumor in patients with cervical lymph node metastasis of unknown primary (MUO) has a great impact on therapy approach and potentially on patient prognosis. Purpose: To assess the diagnostic accuracy of combined positron emission tomography (PET)/computer tomography (CT) for primary tumor detection in cervical metastases of unknown origin compared to PET, CT, and PET+CT side-by-side evaluation. Material and Methods: 39 consecutive patients (eight women, 31 men; mean age 59.9±11.2 years) with MUO were enrolled in this study. PET/CT images were obtained 1 hour after injection of 350 MBq of fluorodeoxyglucose. Oral and intravenous contrast agents were administered in all patients to ensure diagnostic CT data. Fused PET/CT data were evaluated for primary tumor detection. Diagnostic accuracy was calculated and compared with CT alone, PET alone, and side-by-side PET+CT evaluation. Statistical analysis of differences in diagnostic performance between the different imaging procedures was based on the McNemar test. Results: Fused PET/CT depicted the primary tumor in 11 of 39 (28%) patients. In 28 (72%) patients, the primary tumor remained occult. CT revealed the primary in five (13%), PET alone in 10 (26%), and side-by-side evaluation of PET+CT in 10 (26%) of 39 patients. Statistical analysis showed no significant differences between the imaging modalities. Conclusion: PET, side-by-side PET+CT, and PET/CT revealed similar detection rates for primary tumors in cervical MUO patients. Therefore, cervical metastases of an unknown primary may be assessed with either of these imaging modalities. Detection rates with CT were substantially lower. Thus, inclusion of functional data for assessment of cervical MUO patients must be recommended

  8. Housing and sustainable development: perspectives offered by thermal solar energy. Particle emissions: prospective investigation of primary particle emissions in France by 2030

    International Nuclear Information System (INIS)

    Brignon, J.M.; Cauret, L.; Sambat, S.

    2004-09-01

    This publication proposes two investigation reports. A first study proposes a prospective analysis of the housing 'stock' in France and the evolution of global energy consumptions and CO 2 emissions by the housing sector, a prospective study of space heating and hot water needs by defining reference scenarios as well as a target scenario for heating consumption (based on the factor 4 of reduction of emissions by 2050), and an assessment of the contribution of the thermal solar energy applied to winter comfort under the form of direct solar floors and passive solar contributions, and applied to hot water by 2050. The contribution of the thermal solar energy is studied within its regulatory context. An analysis of urban forms is also performed to assess the potential of integration of renewable energy solutions in the existing housing stock, and thus to assess the morphological limits of an attempt of generalized solarization of roofs. The second study proposes a detailed identification and assessment of the various sources of primary particles (combustion, industrial processes, mineral extraction and processing, road transport, waste processing and elimination, agriculture, natural sources, forest fires), providing more precise results and methodological complements for some sources. It also proposes a prospective assessment of emissions and identifies the main factors of particle concentrations in urban environment

  9. Inter-annual trend of the primary contribution of ship emissions to PM2.5 concentrations in Venice (Italy): Efficiency of emissions mitigation strategies

    Science.gov (United States)

    Contini, Daniele; Gambaro, Andrea; Donateo, Antonio; Cescon, Paolo; Cesari, Daniela; Merico, Eva; Belosi, Franco; Citron, Marta

    2015-02-01

    Ships and harbour emissions are currently increasing, due to the increase of tourism and trade, with potential impact on global air pollution and climate. At local scale, in-port ship emissions influence air quality in coastal areas impacting on health of coastal communities. International legislations to reduce ship emissions, both at Worldwide and European levels, are mainly based on the use of low-sulphur content fuel. In this work an analysis of the inter-annual trends of primary contribution, ε, of tourist shipping to the atmospheric PM2.5 concentrations in the urban area of Venice has been performed. Measurements have been taken in the summer periods of 2007, 2009 and 2012. Results show a decrease of ε from 7% (±1%) in 2007 to 5% (±1%) in 2009 and to 3.5% (±1%) in 2012. The meteorological and micrometeorological conditions of the campaigns were similar. Tourist ship traffic during measurement campaigns increased, in terms of gross tonnage, of about 25.4% from 2007 to 2009 and of 17.6% from 2009 to 2012. The decrease of ε was associated to the effect of a voluntary agreement (Venice Blue Flag) for the use of low-sulphur content fuel enforced in the area between 2007 and 2009 and to the implementation of the 2005/33/CE Directive in 2010. Results show that the use of low-sulphur fuel could effectively reduce the impact of shipping to atmospheric primary particles at local scale. Further, voluntary agreement could also be effective in reducing the impact of shipping on local air quality in coastal areas.

  10. Proposition of primary methods for nitrogen oxides emissions reduction at coal-fired 200 MW power unit (Yugoslavia)

    International Nuclear Information System (INIS)

    Repic, B.; Mladenovic, R.; Crnomarkovic, N.

    1997-01-01

    The combustion of coal is followed by increased pollution of the environment with toxic products. Together with the generation of other pollutants, the emission of nitrogen oxides (NO x ) represents, due to its high toxicity, a great environmental risk. Appropriate measures must be taken for lowering NO x emission, both on new facilities and those already in operation. Basic technologies (primary reduction methods) of several generations, developed until now and used in practice, are presented in the paper. The technologies applicable on domestic facilities and adjusted to domestic coals have been given particular consideration. Proposition of primary methods for NO x emission reduction at coal-fired 200 MW power unit at TPS 'Nikola Tesla' is analyzed. The following methods have been considered in detail: flue gases recirculation, multi-stage combustion, low-NO x burners, additional over-fire air, multi-stage air intake into the furnace, staged fuel injection, grinding fineness increase, etc. Considerations were performed according to existing constructive characteristics of the furnace and the burners, and characteristics of used fuels, i. e. lignites from Kolubara pit. (Author)

  11. Time-resolved analysis of primary volatile emissions and secondary aerosol formation potential from a small-scale pellet boiler

    Science.gov (United States)

    Czech, Hendryk; Pieber, Simone M.; Tiitta, Petri; Sippula, Olli; Kortelainen, Miika; Lamberg, Heikki; Grigonyte, Julija; Streibel, Thorsten; Prévôt, André S. H.; Jokiniemi, Jorma; Zimmermann, Ralf

    2017-06-01

    Small-scale pellet boilers and stoves became popular as a wood combustion appliance for domestic heating in Europe, North America and Asia due to economic and environmental aspects. Therefore, an increasing contribution of pellet boilers to air pollution is expected despite their general high combustion efficiency. As emissions of primary organic aerosol (POA) and permanent gases of pellet boilers are well investigated, the scope of this study was to investigate the volatile organic emissions and the formation potential of secondary aerosols for this type of appliance. Fresh and aged emissions were analysed by a soot-particle aerosol time-of-flight mass spectrometry (SP-AMS) and the molecular composition of the volatile precursors with single-photon ionisation time-of-flight mass spectrometry (SPI-TOFMS) at different pellet boiler operation conditions. Organic emissions in the gas phase were dominated by unsaturated hydrocarbons while wood-specific VOCs, e.g. phenolic species or substituted furans, were only detected during the starting phase. Furthermore, organic emissions in the gas phase were found to correlate with fuel grade and combustion technology in terms of secondary air supply. Secondary organic aerosols of optimised pellet boiler conditions (OPT, state-of-the-art combustion appliance) and reduced secondary air supply (RSA, used as a proxy for pellet boilers of older type) were studied by simulating atmospheric ageing in a Potential Aerosol Mass (PAM) flow reactor. Different increases in OA mass (55% for OPT, 102% for RSA), associated with higher average carbon oxidation state and O:C, could be observed in a PAM chamber experiment. Finally, it was found that derived SOA yields and emission factors were distinctly lower than reported for log wood stoves.

  12. EVALUATION OF CORN (Zea mays L.) SEED VIGOR THROUGH THE PRECOCITY OF PRIMARY ROOT EMISSION

    OpenAIRE

    Toledo, Francisco Ferraz de; Novembre, Ana Dionisia da Luz Coelho; Chamma, Helena Maria Carmignani Pescarin; Maschietto, Renata Waldemarin

    1999-01-01

    Foi desenvolvido trabalho baseado na determinação da precocidade da emissão da raiz primária de sementes de milho, em dez lotes de um mesmo cultivar. Este processo constou da distribuição de 200 sementes de cada lote sobre folhas de papel umedecido e, também, rolos de papel, que permaneceram em germinador a 25 °C; de 12 em 12 horas, aquelas que apresentaram emissão da raiz primária foram removidas, contadas e anotadas. Para estabelecer comparação entre os métodos e os lotes, paralelamente, as...

  13. Wavelength conversion devices

    DEFF Research Database (Denmark)

    Mikkelsen, Benny; Durhuus, Terji; Jørgensen, Carsten

    1996-01-01

    system requirements. The ideal wavelength converter should be transparent to the bit rate and signal format and provide an unchirped output signal with both a high extinction ratio and a large signal-to-noise ratio. It should allow conversion to both shorter and longer wavelengths with equal performance...

  14. Primary Emission and the Potential of Secondary Aerosol Formation from Chinese Gasoline Engine Exhaust

    Science.gov (United States)

    Hu, Min; Peng, Jianfei; Qin, Yanhong; Du, Zhuofei; Li, Mengjin; Zheng, Rong; Zheng, Jing; Shang, Dongjie; Lu, Sihua; Wu, Yusheng; Zeng, Limin; Guo, Song; Shao, Min; Wang, Yinhui; Shuai, Shijin

    2017-04-01

    Along with the urbanization and economic growth, vehicle population in China reached 269 million, ranked the second in the world in 2015. Gasoline vehicle is identified to be the main source for urban PM2.5 in China, accounting for 15%-31%. In this study the impact of fuel components on PM2.5 and volatile organic compounds (VOCs) emissions from a gasoline port fuel injection (PFI) engine and a gasoline direct injection (GDI) engine are discussed. Results show that, higher proportion of aromatics, alkenes or sulfur in gasoline fuel will lead to higher PM emissions. The PM from the PFI engine mainly consists of OC and a small amount of EC and inorganic ions, while the PM discharge from the GDI engine mainly consists of EC, OM and a small amount of inorganic ions. Since the GDI engines can reduce fuel consumption and CO2 emissions, and it would become more and more popular in the near future. The characteristics of POM component, emission factors and source profile were investigated from GDI engine, particularly focused on the effect of engine speed, load and the catalyst, which will be very much helpful for source identification as source indicators. Chamber experiments were conducted to quantify the potential of secondary aerosol formation from exhaust of a PFI gasoline engine and China V gasoline fuel. During 4-5 h simulation, equivalent to10 days of atmospheric photo-oxidation in Beijing, the extreme SOA production was 426 ± 85 mg/kg fuel, with high precursors and OH exposure. 14% of SOA measured in the chamber experiments could be explained through the oxidation of speciated single-ring aromatics. Unspeciated precursors, such as intermediate-volatility organic compounds and semi-volatility organic compounds, might be significant for SOA formation from gasoline VOCs. We concluded that reduction of emissions of aerosol precursor gases from vehicles is essential to mediate pollution in China.

  15. Emission Facilities - Air Emission Plants

    Data.gov (United States)

    NSGIC Education | GIS Inventory — Represents the Primary Facility type Air Emission Plant (AEP) point features. Air Emissions Plant is a DEP primary facility type related to the Air Quality Program....

  16. Household Solar Photovoltaics: Supplier of Marginal Abatement, or Primary Source of Low-Emission Power?

    Directory of Open Access Journals (Sweden)

    Graham Palmer

    2013-03-01

    Full Text Available With declining system costs and assuming a short energy payback period, photovoltaics (PV should, at face value, be able to make a meaningful contribution to reducing the emission intensity of Australia’s electricity system. However, solar is an intermittent power source and households remain completely dependent on a “less than green” electricity grid for reliable electricity. Further, much of the energy impact of PV occurs outside of the conventional boundaries of PV life-cycle analyses (LCA. This paper examines these competing observations and explores the broader impacts of a high penetration of household PV using Melbourne, Victoria as a reference. It concludes that in a grid dominated by unsequestered coal and gas, PV provides a legitimate source of emission abatement at high, but declining costs, with the potential for network and peak demand support. It may be technically possible to integrate a high penetration of PV, but the economic and energy cost of accommodating high-penetration PV erodes much of the benefits. Future developments in PV, storage, and integration technologies may allow PV to take on a greater long term role, but in the time horizon usually discussed in climate policy, a large-scale expansion of household PV may hinder rather than assist deep cuts to the emission intensity of Australia’s electricity system.

  17. Short wavelength FELS

    International Nuclear Information System (INIS)

    Sheffield, R.L.

    1991-01-01

    The generation of coherent ultraviolet and shorter wavelength light is presently limited to synchrotron sources. The recent progress in the development of brighter electron beams enables the use of much lower energy electron rf linacs to reach short-wavelengths than previously considered possible. This paper will summarize the present results obtained with synchrotron sources, review proposed short- wavelength FEL designs and then present a new design which is capable of over an order of magnitude higher power to the extreme ultraviolet. 17 refs., 10 figs

  18. Short wavelength FELS

    Energy Technology Data Exchange (ETDEWEB)

    Sheffield, R.L.

    1991-01-01

    The generation of coherent ultraviolet and shorter wavelength light is presently limited to synchrotron sources. The recent progress in the development of brighter electron beams enables the use of much lower energy electron rf linacs to reach short-wavelengths than previously considered possible. This paper will summarize the present results obtained with synchrotron sources, review proposed short- wavelength FEL designs and then present a new design which is capable of over an order of magnitude higher power to the extreme ultraviolet. 17 refs., 10 figs.

  19. Clinical applications of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in carcinoma of unknown primary

    Institute of Scientific and Technical Information of China (English)

    HU Man; YU Jin-ming; ZHAO Wei; ZHANG Pin-liang; JU Gui-fang; FU Zheng; ZHANG Guo-li; KONG Li; YANG Yan-qin; MA Yi-dong

    2011-01-01

    Background Carcinoma of unknown primary (CUP) encompasses a heterogeneous group of tumors with varying clinical features. The management of patients of CUP remains a clinical challenge. The purpose of this study was to evaluate the clinical applications of integrated 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) information in patients with CUP,including detecting the occult primary tumor and effecting on disease therapy.Methods One hundred and forty-nine patients with histologically-proven metastases of CUP were included. For all patients,the conventional diagnostic work-up was unsuccessful in localizing the primary site. Whole-body PET/CT images were obtained approximately 60 minutes after intravenous injection of 350-425 MBq of 18F-FDG.Results In 24.8% of patients,FDG PET/CT detected primary tumors that were not apparent after conventional workup.In this group of patients,the overall sensitivity,specificity,and accuracy rates of FDG PET/CT in detecting unknown primary tumors were 86.0%,87.7%,and 87.2%,respectively. FDG PET/CT imaging also led to the detection of previously unrecognized metastases in 29.5% of patients. Forty-seven (31.5%,47 of 149) patients underwent a change in therapeutic management.Conclusions FDG PET/CT is a valuable tool in patients with CUP,because it assisted in detecting unknown primary tumors and previously unrecognized distant metastases,and optimized the mangement of these patients.

  20. What is the value of emission tomography studies in patients with a primary glioblastoma multiforme treated by 192Ir brachytherapy?

    International Nuclear Information System (INIS)

    Koot, R.W.; Bosch, D.A.; Habraken, J.B.A.; Hulshof, M.C.C.M.; Paans, A.M.J.; Pruim, J.

    2008-01-01

    We studied the use of 201 thallium SPECT and L-[1- 11 C]-tyrosine PET in patients with a primary glioblastoma multiforme treated with 192 Ir brachytherapy after surgery and external beam radiation therapy. We hypothesised that the patients most likely to benefit from further surgery after deterioration would be those with radiation necrosis and would be recognised by a negative emission tomography scan. Twenty-one patients underwent 201 thallium SPECT performed before brachytherapy, and this was repeated in 19 patients when recurrence was suspected. Nine patients also underwent a PET scan at the same time. Nine patients underwent a second operation. SPECT and PET were highly concordant concerning the prediction of radionecrosis and/or tumor recurrence. Repeat surgery did not lead to a significant increase in survival. There was no significant association between the duration of survival and tumor-to-background ratio but the number studied was small. Both SPECT and PET showed highly active lesions, which were proved to be recurrent tumor by clinical and histological follow-up. Although PET and SPECT are both highly sensitive in detecting active tumor tissue, emission tomography was not clinically valuable in the investigation of patients with a primary glioblastoma treated with brachytherapy. (author)

  1. Position emission tomography with or without computed tomography in the primary staging of Hodgkin's lymphoma

    DEFF Research Database (Denmark)

    Hutchings, Martin; Loft, Annika; Hansen, Mads

    2006-01-01

    BACKGROUND AND OBJECTIVES: In order to receive the most appropriate therapy, patients with Hodgkin's lymphoma (HL) must be accurately stratified into different prognostic staging groups. Computed tomography (CT) plays a pivotal role in the conventional staging. The aim of the present study...... was to investigate the value of positron emission tomography using 2-[18F]fluoro-2-deoxy-D-glucose (FDG-PET) and combined FDG-PET/CT for the staging of HL patients, and the impact on the choice of treatment. DESIGN AND METHODS: Ninety-nine consecutive, prospectively included patients had FDG-PET and CT...

  2. Short wavelength FELs using the SLAC linac

    International Nuclear Information System (INIS)

    Winick, H.; Bane, K.; Boyce, R.

    1993-08-01

    Recent technological developments have opened the possibility to construct a device which we call a Linac Coherent Light Source (LCLS); a fourth generation light source, with brightness, coherence, and peak power far exceeding other sources. Operating on the principle of the free electron laser (FEL), the LCLS would extend the range of FEL operation to much aborter wavelength than the 240 mn that has so far been reached. We report the results of studies of the use of the SLAC linac to drive an LCLS at wavelengths from about 3-100 nm initially and possibly even shorter wavelengths in the future. Lasing would be achieved in a single pass of a low emittance, high peak current, high energy electron beam through a long undulator. Most present FELs use an optical cavity to build up the intensity of the light to achieve lasing action in a low gain oscillator configuration. By eliminating the optical cavity, which is difficult to make at short wavelengths, laser action can be extended to shorter wavelengths by Self-Amplified-Spontaneous-Emission (SASE), or by harmonic generation from a longer wavelength seed laser. Short wavelength, single pass lasers have been extensively studied at several laboratories and at recent workshops

  3. The use of the acoustic emission for the components of the primary circuit of the nuclear power plants

    International Nuclear Information System (INIS)

    Svoboda, V.

    1992-01-01

    Full text: The Modrany Engineering Works (Modranske strojirny) is a producer and a final supplier of the main connecting piping circuit systems and valves for the nuclear power plants (type VVER 440 and VVER 1000) built in Czechoslovakia. Besides the delivery and assembly of valves and components methods there were developed for a monitoring of the stated equipment ability of a service in the Material and Diagnostic Laboratory, which is a part of the company. An important object of this work is to obtain a sufficient set of data and to work out suitable methods, on the basis of which it would be possible to perform a serious estimation of residual service life of the main piping components after certain service operation of the nuclear power plant. During the operation of a nuclear power station a failure of the main piping circuit could happen in either of two possible modes: 1.) A sudden break - by an unstable defect propagation leading to a. final fracture of the piping; 2) A fatigue failure - which is characterised by a gradual subcritical growth of defect in relation to the loading parameters. This process is frequently accelerated by further processes, e.g. corrosion. It is therefore suitable to use such physical and mechanical quantities, which characterize the material damage. Acoustic emission signals belongs to these quantities. A knowledge of the response of these signals in relation to the damage of the material gives us the possibility to evaluate the residual life of the piping containing defects. The importance of this is increasing mainly after a long period of service. She paper deals in details with experience gained in application of acoustic emission, during pressure tests of primary circuit components (elbow, welds, T- junction etc) in laboratory conditions which imitate those in service. There are shown some results of cyclic fatigue tests by internal pressure on prototypes models and specimen. Acoustic emission method represents the

  4. Secondary emission yield at low-primary energies of magnetic materials for anti-multipactor applications

    CERN Document Server

    Aguilera, L; Olano, L; Casas, A; Morales, P; Vázquez, M; Galán, L; Caspers, F; Costa-Pinto, P; Taborelli, M; Raboso, D

    2014-01-01

    Secondary electron emission processes under electron bombardment are central to many effects at surfaces and interfaces, and to many in vacuum high power RF electronic devices where multipactor can be very intense [1,2]. Ferrite materials are usually used in microwave components used in space telecommunication systems, as circulators, phase-shifters, switches, and isolators. The physics of the multipactor phenomenon existing in microwave devices based on ferrite materials is an important issue and it is urgent to be researched [3]. One difficulty in the analysis of the multipactor effect in RF components containing ferrite lies on the fact that this material is an anysotropic magnetic medium controlled by an applied permanent magnetic field, which is used to magnetize the ferrite material. SEY and other properties (structure, magnetic behaviour,...) of soft-magnetic materials were studied in this work. MnZn soft ferrites magnets are suitable in the situation of frequency < 3MHz, low loss and high μi. Comp...

  5. Molecular characterization of urban organic aerosol in tropical India: contributions of primary emissions and secondary photooxidation

    Directory of Open Access Journals (Sweden)

    P. Q. Fu

    2010-03-01

    Full Text Available Organic molecular composition of PM10 samples, collected at Chennai in tropical India, was studied using capillary gas chromatography/mass spectrometry. Fourteen organic compound classes were detected in the aerosols, including aliphatic lipids, sugar compounds, lignin products, terpenoid biomarkers, sterols, aromatic acids, hydroxy-/polyacids, phthalate esters, hopanes, Polycyclic Aromatic Hydrocarbons (PAHs, and photooxidation products from biogenic Volatile Organic Compounds (VOCs. At daytime, phthalate esters were found to be the most abundant compound class; however, at nighttime, fatty acids were the dominant one. Di-(2-ethylhexyl phthalate, C16 fatty acid, and levoglucosan were identified as the most abundant single compounds. The nighttime maxima of most organics in the aerosols indicate a land/sea breeze effect in tropical India, although some other factors such as local emissions and long-range transport may also influence the composition of organic aerosols. However, biogenic VOC oxidation products (e.g., 2-methyltetrols, pinic acid, 3-hydroxyglutaric acid and β-caryophyllinic acid showed diurnal patterns with daytime maxima. Interestingly, terephthalic acid was maximized at nighttime, which is different from those of phthalic and isophthalic acids. A positive relation was found between 1,3,5-triphenylbenzene (a tracer for plastic burning and terephthalic acid, suggesting that the field burning of municipal solid wastes including plastics is a significant source of terephthalic acid. Organic compounds were further categorized into several groups to clarify their sources. Fossil fuel combustion (24–43% was recognized as the most significant source for the total identified compounds, followed by plastic emission (16–33%, secondary oxidation (8.6–23%, and microbial/marine sources (7.2–17%. In contrast, the contributions of terrestrial plant waxes (5.9–11% and biomass burning (4.2–6.4% were relatively

  6. 18F-fluorodeoxyglucose positron emission tomography and magnetic resonance imaging findings of primary intracranial histiocytic sarcoma in a dog

    International Nuclear Information System (INIS)

    Kang, B.T.; Park, C.; Yoo, J.H.; Gu, S.H.; Jang, D.P.; Kim, Y.B.; Woo, E.J.; Kim, D.Y.; Cho, Z.H.; Park, H.M.

    2009-01-01

    A 10-year-old, neutered male, Maltese dog presented with a three week history of intention tremor, right hind limb rigidity, poor coordination, and occasional circling to the left. On magnetic resonance imaging (MRI) of the brain, a mass was identified in the right occipital lobe and cerebellum. Three weeks after the initial MRI scan, we performed an sup(18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) of the brain. The FDG-PET demonstrated areas of hypermetabolism in the right occipital lobe, cerebellum, pons, and medulla oblongata. When the standardized uptake value was calculated, the hypermetabolic lesion was higher than the gray matter values. The anatomical location of the hypermetabolic lesion was more precisely identified by the PET-MRI fusion images. The dog was definitively diagnosed as a primary histiocytic sarcoma of the brain. This is the first report of PET findings of an intracranial histiocytic sarcoma in a dog

  7. 18F-fluorodeoxyglucose positron emission tomography optimizes neoadjuvant chemotherapy for primary breast cancer to achieve pathological complete response

    International Nuclear Information System (INIS)

    Ueda, Shigeto; Saeki, Toshiaki; Shigekawa, Takashi

    2012-01-01

    The background of this study was to assess the usefulness of positron emission tomography combined with computed tomography using 18 F-fluorodeoxyglucose (FDG positron emission tomography (PET)/CT) for optimizing chemotherapy during neoadjuvant chemotherapy for primary breast cancer. One hundred and eight patients (110 tumors) with breast cancer (≥2 cm, stages II and III) received neoadjuvant chemotherapy consisting of an anthracycline-based regimen and taxane. The maximal value of the baseline standardized uptake value (SUV) and the change in SUV after four cycles of an anthracycline-based regimen relative to baseline SUV were assessed for predicting pathological complete response (pCR) after sequential taxane. Tumors with pCR had significantly higher baseline SUV (9.3±3.7 SD) compared to those with non-pCR (7.2±3.8 SD) (p=0.02), but there was a considerable overlap between two groups. On PET scan after four cycles of chemotherapy, thirty-three patients (33.7%) with a 72.1% or greater reduction in SUV were considered as responders and the performance in predicting pCR had a sensitivity of 88.9% and specificity of 78.7%. The baseline SUV could not be a useful indicator for predicting pCR due to the wide range in sensitivity. On the other hand, a relative change in SUV after completion of an anthracycline-based regimen could be useful for predicting pCR. (author)

  8. The added value of 18F-fluorodeoxyglucose positron emission tomography computed tomography in patients with neck lymph node metastases from an unknown primary malignancy.

    Science.gov (United States)

    Prowse, S J B; Shaw, R; Ganeshan, D; Prowse, P M; Hanlon, R; Lewis-Jones, H; Wieshmann, H

    2013-08-01

    The search for a primary malignancy in patients with a metastatic cervical lymph node is challenging yet ultimately of utmost clinical importance. This study evaluated the efficacy of positron emission tomography computed tomography in detecting the occult primary, within the context of a tertiary referral centre head and neck cancer multidisciplinary team tumour board meeting. Thirty-two patients (23 men and 9 women; mean and median age, 61 years) with a metastatic cervical lymph node of unknown primary origin, after clinical examination and magnetic resonance imaging, underwent positron emission tomography computed tomography. The primary tumour detection rate was 50 per cent (16/32). Positron emission tomography computed tomography had a sensitivity of 94 per cent (16/17) and a specificity of 67 per cent (10/15). Combining these results with those of 10 earlier studies of similar patients gave an overall detection rate of 37 per cent. Positron emission tomography computed tomography has become an important imaging modality. To date, it has the highest primary tumour detection rate, for head and neck cancer patients presenting with cervical lymph node metastases from an unknown primary.

  9. The Effect of Learning Disability on Contralateral Suppression of Otoacoustic Emissions in Primary Students

    Directory of Open Access Journals (Sweden)

    Saeid Sarough Farahani

    2006-06-01

    Full Text Available Background and Aim: One of the most significant complaints of children with learning disability (LD is difficulty in understanding speech in the presence of background noise. Different studies have shown that the medial olivocochlear bundle(MOCB may play a role in hearing in noise. The MOCB function can be evaluated by the contralateral suppression of tone burst evoked otoacoustic emissions (TBEOAEs.The aim of the present study was to evaluate frequency specifications of MOCB by the contralateral suppression of TBEOAEs at 1,2,3 and 4 KHz in response to contralateral white noise in LD students. Materials and Methods: This case-control study was conducted on 34 LD students aged 7-11 years and 31 normal students matched for age.The contralateral suppression of TBEOAEs was evaluated by comparing TBEOAEs amplitudes with and without contralateral white noise. Results: In the absence of noise there was no significant difference between TBEOAEs amplitudes of two groups. In the presence of noise significant decrease was seen in TBEOAEs amplitudes at 1,2,3 and 4 KHz in both groups. In LD students the amount of this decrement at 1,2 and 4 KHz was lower than in the normal students. Conclusion: A significant diminished suppression effect at 1,2 and 4 KHz in LD students indicates that at these frequency regions MOCB function was reduced. Therefore it suggests that the assessment of MOCB by evaluating the suppression effect of TBEOAEs included in the test battery approach used in the diagnostic of LD students.

  10. Wavelength conversion technology

    DEFF Research Database (Denmark)

    Stubkjær, Kristian

    1998-01-01

    Optical wavelength conversion is currently attracting much interest. This is because it enables full flexibility and eases management of WDM fibre networks. The tutorial will review existing and potential application areas. Examples of node architectures and network demonstrators that use wavelen...

  11. Electric vehicles, primary energy sources and CO2 emissions: Romanian case study

    International Nuclear Information System (INIS)

    Varga, Bogdan Ovidiu

    2013-01-01

    Starting on the 24th of April, 2011, the Romanian government offered to subsidize all potential buyers of electric vehicles, both private and corporate, offering 25% off of the retail price up to 5000 euros with no pollution tax. The Romanian government encourages all governmental institutions to consider buying electric vehicles when deciding to change their existing vehicles stock. This decision is strictly related to the Romanian government's approval of a long-term Energy Strategy, building on the National Energy Strategy for the Medium Term. The government's strategy emphasizes increasing energy efficiency and boosting renewable energy use. The first electric vehicles distributed in the Romanian market are the Citroen-C-Zero, the Mitsubishi i-MiEV, the Renault Kangoo Z.E. and the Renault Fluence Z.E. The energy consumption of these vehicles was analyzed, considering the CO 2 generation characteristics of a Romanian electric power plant. -- Highlights: ► Tax and governmental support for electrical vehicles in Romania. ► Evaluate the CO 2 pollution of the electrical vehicles in Romania's case. ► Comprehensive understanding of the influence of primary energy source over the pollution of an electrical vehicle. ► Approach to decrees the pollution of the electrical vehicles.

  12. Long wavelength scintillators for fiber-optic applications

    International Nuclear Information System (INIS)

    Lyons, P.B.; Franks, L.; Lutz, S.; Flournoy, J.; Fullman, E.

    1980-01-01

    The use of fiber optics in plasma diagnostics has spurred the development of long wavelength scintillators with fast temporal characteristics. In this paper we describe several new liquid scintillator systems with fluorescent emissions maxima up to 730 nm. Subnanosecond scintillator FWHM response times have been obtained by the operation of liquid scintillators at elevated temperatures. Data on fiber system sensitivity versus fiber length and scintillator emission wavelength will be presented

  13. Solar Observations at Submillimeter Wavelengths

    Science.gov (United States)

    Kaufmann, P.

    We review earlier to recent observational evidences and theoretical motivations leading to a renewed interest to observe flares in the submillimeter (submm) - infrared (IR) range of wavelengths. We describe the new solar dedicated submillimeter wave telescope which began operations at El Leoncito in the Argentina Andes: the SST project. It consists of focal plane arrays of two 405 GHz and four 212 GHz radiometers placed in a 1.5-m radome-enclosed Cassegrain antenna, operating simultaneously with one millisecond time resolution. The first solar events analyzed exhibited the onset of rapid submm-wave spikes (100-300 ms), well associated to other flare manifestations, especially at X-rays. The spikes positions were found scattered over the flaring source by tens of arcseconds. For one event an excellent association was found between the gamma-ray emission time profile and the rate of occurrence of submm-wave rapid spikes. The preliminary results favour the idea that bulk burst emissions are a response to numerous fast energetic injections, discrete in time, produced at different spatial positions over the flaring region. Coronal mass ejections were associated to the events studied. Their trajectories extrapolated to the solar surface appear to correspond to the onset time of the submm-wave spikes, which might represent an early signature of the CME's initial acceleration process.

  14. Wavelength sweepable laser source

    DEFF Research Database (Denmark)

    2014-01-01

    Wavelength sweepable laser source is disclosed, wherein the laser source is a semiconductor laser source adapted for generating laser light at a lasing wavelength. The laser source comprises a substrate, a first reflector, and a second reflector. The first and second reflector together defines...... and having a rest position, the second reflector and suspension together defining a microelectromechanical MEMS oscillator. The MEMS oscillator has a resonance frequency and is adapted for oscillating the second reflector on either side of the rest position.; The laser source further comprises electrical...... connections adapted for applying an electric field to the MEMS oscillator. Furthermore, a laser source system and a method of use of the laser source are disclosed....

  15. Organic molecular composition of marine aerosols over the Arctic Ocean in summer: contributions of primary emission and secondary aerosol formation

    Directory of Open Access Journals (Sweden)

    P. Q. Fu

    2013-02-01

    Full Text Available Organic molecular composition of marine aerosol samples collected during the MALINA cruise in the Arctic Ocean was investigated by gas chromatography/mass spectrometry. More than 110 individual organic compounds were determined in the samples and were grouped into different compound classes based on the functionality and sources. The concentrations of total quantified organics ranged from 7.3 to 185 ng m−3 (mean 47.6 ng m−3, accounting for 1.8–11.0% (4.8% of organic carbon in the marine aerosols. Primary saccharides were found to be dominant organic compound class, followed by secondary organic aerosol (SOA tracers formed from the oxidation of biogenic volatile organic compounds (VOCs such as isoprene, α-pinene and β-caryophyllene. Mannitol, the specific tracer for airborne fungal spores, was detected as the most abundant organic species in the samples with a concentration range of 0.052–53.3 ng m−3 (9.2 ng m−3, followed by glucose, arabitol, and the isoprene oxidation products of 2-methyltetrols. Biomass burning tracers such as levoglucosan are evident in all samples with trace levels. On the basis of the tracer-based method for the estimation of fungal-spore OC and biogenic secondary organic carbon (SOC, we estimate that an average of 10.7% (up to 26.2% of the OC in the marine aerosols was due to the contribution of fungal spores, followed by the contribution of isoprene SOC (mean 3.8% and α-pinene SOC (2.9%. In contrast, only 0.19% of the OC was due to the photooxidation of β-caryophyllene. This study indicates that primary organic aerosols from biogenic emissions, both from long-range transport of mid-latitude aerosols and from sea-to-air emission of marine organics, as well as secondary organic aerosols formed from the photooxidation of biogenic VOCs are important factors controlling the organic chemical composition of marine aerosols in the Arctic Ocean.

  16. Spectral filter for splitting a beam with electromagnetic radiation having wavelengths in the extreme ultraviolet (EUV) or soft X-Ray (Soft X) and the infrared (IR) wavelength range

    NARCIS (Netherlands)

    van Goor, F.A.; Bijkerk, Frederik; van den Boogaard, Toine; van den Boogaard, A.J.R.; van der Meer, R.

    2012-01-01

    Spectral filter for splitting the primary radiation from a generated beam with primary electromagnetic radiation having a wavelength in the extreme ultraviolet (EUV radiation) or soft X-ray (soft X) wavelength range and parasitic radiation having a wavelength in the infrared wavelength range (IR

  17. Occult primary tumors of the head and neck: accuracy of thallium 201 single-photon emission computed tomography and computed tomography and/or magnetic resonance imaging

    NARCIS (Netherlands)

    van Veen, S. A.; Balm, A. J.; Valdés Olmos, R. A.; Hoefnagel, C. A.; Hilgers, F. J.; Tan, I. B.; Pameijer, F. A.

    2001-01-01

    To determine the accuracy of thallium 201 single-photon emission computed tomography (thallium SPECT) and computed tomography and/or magnetic resonance imaging (CT/MRI) in the detection of occult primary tumors of the head and neck. Study of diagnostic tests. National Cancer Institute, Amsterdam,

  18. [Positron emission tomography combined with computed tomography in the initial evaluation and response assessment in primary central nervous system lymphoma].

    Science.gov (United States)

    Mercadal, Santiago; Cortés-Romera, Montserrat; Vélez, Patricia; Climent, Fina; Gámez, Cristina; González-Barca, Eva

    2015-06-08

    To evaluate the role of positron emission tomography combined with computed tomography (PET-CT) in the initial evaluation and response assessment in primary central nervous system lymphoma (PCNSL). Fourteen patients (8 males) with a median age 59.5 years diagnosed of PCNSL. A brain PET-CT and magnetic resonance imaging (MRI) were performed in the initial evaluation. In 7 patients a PET-CT after treatment was performed. PET-CT showed at diagnosis 31 hypermetabolic focuses and MRI showed 47 lesions, with a good grade of concordance between both (k = 0.61; P = .005). In the response assessment, correlation between both techniques was good, and PET-CT was helpful in the appreciation of residual MRI lesions. Overall survival at 2 years of negative vs. positive PET-CT at the end of treatment was 100 vs. 37.5%, respectively (P = .045). PET-CT can be useful in the initial evaluation of PCNSL, and especially in the assessment of response. Despite the fact that PET-CT detects less small lesions than MRI, a good correlation between MRI and PET-CT was observed. It is effective in the evaluation of residual lesions. Prospective studies are needed to confirm their possible prognostic value. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  19. Life cycle air emissions impacts and ownership costs of light-duty vehicles using natural gas as a primary energy source.

    Science.gov (United States)

    Luk, Jason M; Saville, Bradley A; MacLean, Heather L

    2015-04-21

    This paper aims to comprehensively distinguish among the merits of different vehicles using a common primary energy source. In this study, we consider compressed natural gas (CNG) use directly in conventional vehicles (CV) and hybrid electric vehicles (HEV), and natural gas-derived electricity (NG-e) use in plug-in battery electric vehicles (BEV). This study evaluates the incremental life cycle air emissions (climate change and human health) impacts and life cycle ownership costs of non-plug-in (CV and HEV) and plug-in light-duty vehicles. Replacing a gasoline CV with a CNG CV, or a CNG CV with a CNG HEV, can provide life cycle air emissions impact benefits without increasing ownership costs; however, the NG-e BEV will likely increase costs (90% confidence interval: $1000 to $31 000 incremental cost per vehicle lifetime). Furthermore, eliminating HEV tailpipe emissions via plug-in vehicles has an insignificant incremental benefit, due to high uncertainties, with emissions cost benefits between -$1000 and $2000. Vehicle criteria air contaminants are a relatively minor contributor to life cycle air emissions impacts because of strict vehicle emissions standards. Therefore, policies should focus on adoption of plug-in vehicles in nonattainment regions, because CNG vehicles are likely more cost-effective at providing overall life cycle air emissions impact benefits.

  20. A regional high-resolution emission inventory of primary air pollutants in 2012 for Beijing and the surrounding five provinces of North China

    Science.gov (United States)

    Liu, Huanjia; Wu, Bobo; Liu, Shuhan; Shao, Panyang; Liu, Xiangyang; Zhu, Chuanyong; Wang, Yong; Wu, Yiming; Xue, Yifeng; Gao, Jiajia; Hao, Yan; Tian, Hezhong

    2018-05-01

    A high resolution regional emission inventory of typical primary air pollutants (PAPs) for the year 2012 in Beijing and the surrounding five provinces (BSFP) of North China is developed. It is compiled with the combination of bottom-up and top-down methods, based on city-level collected activity data and the latest updated specific emission factors for different sources. The considered sources are classified into 12 major categories and totally 36 subcategories with respect to their multi-dimensional characteristics, such as economic sector, combustion facility or industrial process, installed air pollution control devices, etc. Power plant sector is the dominant contributor of NOX emissions with an average contribution of 34.1%, while VOCs emissions are largely emitted from industrial process sources (33.9%). Whereas, other stationary combustion sources represent major sources of primary PM2.5, PM10 and BC emissions, accounting for 22.7%, 30.0% and 33.9% of the total emissions, respectively. Hebei province contributes over 34% of the regional total CO emissions because of huge volume of iron and steel production. By comparison, Shandong province ranks as the biggest contributor for NOX, PM10, PM2.5, SO2, VOCs and OC. Further, the BSFP regional total emissions are spatially distributed into grid cells with a high resolution of 9 km × 9 km using GIS tools and surrogate indexes, such regional population, gross domestic product (GDP) and the types of arable soils. The highest emission intensities are mainly located in Beijing-Tianjin-Tangshan area, Jinan-Laiwu-Zibo area and several other cities such as Shijiazhuang, Handan, and Zhengzhou. Furthermore, in order to establish a simple method to estimate and forecast PAPs emissions with macroscopic provincial-level statistical parameters in China, multi-parameter regression equations are firstly developed to estimate emissions outside the BSFP region with routine statistics (e.g. population, total final coal consumption

  1. The role of 18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography in the management of patients with carcinoma of unknown primary.

    Science.gov (United States)

    Deonarine, P; Han, S; Poon, F W; de Wet, C

    2013-08-01

    Carcinoma of unknown primary is one of the ten most frequent cancers worldwide. Its median survival time is less than 10 months. Detecting primary tumour locations and/or occult metastatic lesions may inform definitive treatment and improve patients' prognosis. We aimed to determine: (1) the sensitivity, specificity and accuracy of (18)F-fluoro-2-deoxyglucose positron emission tomography/computed tomography; (2) its detection rate of primary tumour locations and occult metastases and (3) factors associated with improved survival times. We retrospectively reviewed all cases in the West of Scotland for the period 1 December 2007 to 31 May 2011 that met all our selection criteria: (1) diagnosis of carcinoma of unknown primary; (2) a thorough but negative 'work-up' and (3) (18)F-fluoro-2-deoxyglucose positron emission tomography/computed tomography report. Statistical methods included frequencies, Kaplan-Meier graphs and log-rank tests to compare survival times. (18)F-fluoro-2-deoxyglucose positron emission tomography/computed tomography detected primary tumour sites in 19/51 (37.3%) and occult metastases in 28/51 (54.9%) of eligible patients. Its sensitivity, specificity and accuracy were 79.2%, 70.4% and 74.5%, respectively; 20/51 (39.2%) patients died during the study period with a median survival of 8.4 months (range 21.4, SD ± 6.2). The number of metastatic locations was strongly associated with survival (p = 0.002), but detection of a primary tumour site (p = 0.174) or histopathology (p = 0.301) was not. (18)F-fluoro-2-deoxyglucose positron emission tomography/computed tomography detected occult metastatic sites in the majority and a primary cancer location in a substantial minority of patients. Our results were comparable with international literature and may indicate that (18)F-fluoro-2-deoxyglucose positron emission tomography/computed tomography have an early role to improve the accuracy of cancer staging and to optimise carcinoma of unknown

  2. Simulation of nitrous oxide and nitric oxide emissions from tropical primary forests in the Costa Rican Atlantic Zone

    Science.gov (United States)

    Shuguanga Liu; William A. Reiners; Michael Keller; Davis S. Schimel

    2000-01-01

    Nitrous oxide (N2O) and nitric oxide (NO) are important atmospheric trace gases participating in the regulation of global climate and environment. Predictive models on the emissions of N2O and NO emissions from soil into the atmosphere are required. We modified the CENTURY model (Soil Sci. Soc. Am. J., 51 (1987) 1173) to simulate the emissions of N2O and NO from...

  3. Long wavelength irregularities in the equatorial electrojet

    International Nuclear Information System (INIS)

    Kudeki, E.; Farley, D.T.; Fejer, B.G.

    1982-01-01

    We have used the radar interferometer technique at Jicamarca to study in detail irregularities with wavelengths of a few kilometers generated in the unstable equatorial electrojet plasma during strong type 1 conditions. In-situ rocket observations of the same instability process are discussed in a companion paper. These large scale primary waves travel essentially horizontally and have large amplitudes. The vertical electron drift velocities driven by the horizontal wave electric fields reach or exceed the ion-acoustic velocity even though the horizontal phase velocity of the wave is considerably smaller. A straightforward extension to the long wavelength regime of the usual linear theory of the electrojet instability explains this and several other observed features of these dominant primary waves

  4. Small global effect on terrestrial net primary production due to increased fossil fuel aerosol emissions from East Asia during the last decade.

    Science.gov (United States)

    O'Sullivan, Michael; Rap, Alex; Reddington, Carly; Spracklen, Dominick; Buermann, Wolfgang

    2016-04-01

    The global terrestrial carbon sink has increased since the start of this century at a time of rapidly growing carbon dioxide emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning have increased the diffuse fraction of incoming solar radiation and the efficiency of photosynthesis leading to increased plant carbon uptake. Using a combination of atmospheric and biospheric models, we find that changes in diffuse light associated with fossil fuel aerosol emission accounts for only 2.8% of the increase in global net primary production (1.221 PgC/yr) over the study period 1998 to 2007. This relatively small global signal is however a result of large regional compensations. Over East Asia, the strong increase in fossil fuel emissions contributed nearly 70% of the increased plant carbon uptake (21 TgC/yr), whereas the declining fossil fuel aerosol emissions in Europe and North America contributed negatively (-16% and -54%, respectively) to increased plant carbon uptake. At global scale, we also find the CO2 fertilization effect on photosynthesis to be the dominant driver of increased plant carbon uptake, in line with previous studies. These results suggest that further research into alternative mechanisms by which fossil fuel emissions could increase carbon uptake, such as nitrogen deposition and carbon-nitrogen interactions, is required to better understand a potential link between the recent changes in fossil fuel emissions and terrestrial carbon uptake.

  5. Long wavelength irregularities in the equatorial electrojet

    OpenAIRE

    Kudeki, E.; Farley, D. T.; Fejer, Bela G.

    1982-01-01

    We have used the radar interferometer technique at Jicamarca to study in detail irregularities with wavelengths of a few kilometers generated in the unstable equatorial electrojet plasma during strong type 1 conditions. In-situ rocket observations of the same instability process are discussed in a companion paper. These large scale primary waves travel essentially horizontally and have large amplitudes. The vertical electron drift velocities driven by the horizontal wave electric fields reach...

  6. Primary neuroendocrine carcinoma of breast with liver and bone metastasis detected with fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography

    International Nuclear Information System (INIS)

    Kamaleshwaran, Koramadai Karuppusamy; Mohanan, Vyshak; Shibu, Deepu; Radhakrishnan, Edathuruthy Kalarikal; Shinto, Ajit Sugunan

    2014-01-01

    Cases of primary neuroendocrine carcinoma (NEC) of the breast have been reported, though rare. We report the case of a 45-year-old woman presented with jaundice and evaluated to have liver metastasis from neuroendocrine origin. She underwent whole body positron emission tomography/computed tomography, which showed left breast lesion and bone metastasis. Fine-needle aspiration (FNA) of breast revealed a NEC. A diagnosis of a primary NEC of the breast was rendered with hepatic and bone metastasis. She was treated with peptide receptor radionuclide therapy and is on follow-up

  7. Dependence of secondary electron emission on the incident angle and the energy of primary electrons bombarding bowl-structured beryllium surfaces

    International Nuclear Information System (INIS)

    Kawata, Jun; Ohya, Kaoru.

    1994-01-01

    A Monte Carlo simulation of the secondary electron emission from beryllium is combined with a model of bowl structure for surface roughness, for analyzing the difference between the electron emissions for normal and oblique incidences. At normal incidence, with increasing the roughness parameter H/W, the primary energy E pm at which the maximum electron yield occurs becomes higher, and at more than the E pm , the decrease in the yield is slower; where H and W are the depth and width of the bowl structure, respectively. The dispersion of incident angle to the microscopic surface causes a small increase in the yield at oblique incidence, whereas the blocking of primary electrons from bombarding the bottom of the structure causes an opposite trend. The strong anisotropy in the polar angular distribution with respect to the azimuthal angle is calculated at oblique incidence. (author)

  8. Contrast-enhanced [18F] fluorodeoxyglucose-positron emission tomography-computed tomography as an initial imaging modality in patients presenting with metastatic malignancy of undefined primary origin

    International Nuclear Information System (INIS)

    Jain, Avani; Srivastava, Madhur Kumar; Pawaskar, Alok Suresh; Shelley, Simon; Elangovan, Indirani; Jain, Hasmukh; Pandey, Somnath; Kalal, Shilpa; Amalachandran, Jaykanth

    2005-01-01

    To evaluate the advantages of contrast enhanced F-18-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-contrast enhanced CT [CECT]) when used as an initial imaging modality in patients presenting with metastatic malignancy of undefined primary origin (MUO). A total of 243 patients with fine needle aspiration cytology/biopsy proven MUO were included in this prospective study. Patients who were thoroughly evaluated for primary or primary tumor was detected by any other investigation were excluded from the analysis. Totally, 163 patients with pathological diagnosis of malignancy but no apparent sites of the primary tumor were finally selected for analysis. The site of probable primary malignancy suggested by PET-CECT was confirmed by biopsy/follow-up. PET-CECT suggested probable site of primary in 128/163 (78.52%) patients. In 30/35 remaining patients, primary tumor was not detected even after extensive work-up. In 5 patients, where PET-CECT was negative, primary was found on further extensive investigations or follow-up. The sensitivity, specificity, positive predictive value and negative predictive value of the study were 95.76%, 66.67%, 88.28% and 85.71% respectively. F-18 FDG PET-CECT aptly serves the purpose of initial imaging modality owing to high sensitivity, negative and positive predictive value. PET-CECT not only surveys the whole body for the primary malignancy but also stages the disease accurately. Use of contrast improves the diagnostic utility of modality as well as help in staging of the primary tumor. Although benefits of using PET-CECT as initial diagnostic modality are obvious from this study, there is a need for a larger study comparing conventional methods for diagnosing primary in patients with MUO versus PET-CECT

  9. Contrast-enhanced [18F] fluorodeoxyglucose-positron emission tomography-computed tomography as an initial imaging modality in patients presenting with metastatic malignancy of undefined primary origin.

    Science.gov (United States)

    Jain, Avani; Srivastava, Madhur Kumar; Pawaskar, Alok Suresh; Shelley, Simon; Elangovan, Indirani; Jain, Hasmukh; Pandey, Somnath; Kalal, Shilpa; Amalachandran, Jaykanth

    2015-01-01

    To evaluate the advantages of contrast enhanced F-18-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-contrast enhanced CT [CECT]) when used as an initial imaging modality in patients presenting with metastatic malignancy of undefined primary origin (MUO). A total of 243 patients with fine needle aspiration cytology/biopsy proven MUO were included in this prospective study. Patients who were thoroughly evaluated for primary or primary tumor was detected by any other investigation were excluded from the analysis. Totally, 163 patients with pathological diagnosis of malignancy but no apparent sites of the primary tumor were finally selected for analysis. The site of probable primary malignancy suggested by PET-CECT was confirmed by biopsy/follow-up. PET-CECT suggested probable site of primary in 128/163 (78.52%) patients. In 30/35 remaining patients, primary tumor was not detected even after extensive work-up. In 5 patients, where PET-CECT was negative, primary was found on further extensive investigations or follow-up. The sensitivity, specificity, positive predictive value and negative predictive value of the study were 95.76%, 66.67%, 88.28% and 85.71% respectively. F-18 FDG PET-CECT aptly serves the purpose of initial imaging modality owing to high sensitivity, negative and positive predictive value. PET-CECT not only surveys the whole body for the primary malignancy but also stages the disease accurately. Use of contrast improves the diagnostic utility of modality as well as help in staging of the primary tumor. Although benefits of using PET-CECT as initial diagnostic modality are obvious from this study, there is a need for a larger study comparing conventional methods for diagnosing primary in patients with MUO versus PET-CECT.

  10. Unusual presentation of metastatic carcinoma cervix with clinically silent primary identified by 18F-flouro deoxy glucose positron emission tomography/computed tomography

    International Nuclear Information System (INIS)

    Senthil, Raja; Mohapatra, Ranjan Kumar; Srinivas, Shripriya; Sampath, Mouleeswaran Koramadai; Sundaraiya, Sumati

    2016-01-01

    Carcinoma cervix is the most common gynecological malignancy among Indian women. The common symptoms at presentation include abnormal vaginal bleeding, unusual discharge from the vagina, or pain during coitus and postmenopausal bleeding. Rarely, few patients may present with distant metastases without local symptoms. We present two patients with an unusual presentation of metastatic disease without any gynecological symptoms, where 18 F-flouro deoxy glucose positron emission tomography/computed tomography helped in identifying the primary malignancy in the uterine cervix

  11. Primary marine aerosol emissions from the Mediterranean Sea during pre-bloom and oligotrophic conditions: correlations to seawater chlorophyll a from a mesocosm study

    OpenAIRE

    Schwier , A. N.; Rose , C.; Asmi , E.; Ebling , A. M.; Landing , W. M.; Marro , S.; Pedrotti , M.-L.; Sallon , A.; Iuculano , F.; Agusti , S.; Tsiola , A.; Pitta , P.; Louis , J.; Guieu , C.; Gazeau , F.

    2015-01-01

    The effect of ocean acidification and changing water conditions on primary (and secondary) marine aerosol emissions is not well understood on a regional or a global scale. To investigate this effect as well as the indirect effect on aerosol that changing biogeochemical parameters can have, ~ 52 m3 pelagic mesocosms were deployed for several weeks in the Mediterranean Sea during both winter pre-bloom and summer oligotrophic conditions and were subjected to various levels of C...

  12. The wavelength dependence of polarization in NGC 2023

    International Nuclear Information System (INIS)

    Rolph, C. D.; Scarrott, S. M.

    1989-01-01

    NGC 2023 is a bright reflection nebula illuminated by the central star HD37903. At 2 microns the nebula is seen solely by reflected light from the central star but in the NIR there is excess radiation that is supposed to arise from thermal emission from a population of small grains (Sellgren, 1984). The unexpectedly high surface brightness at R and I wavelengths has led to the suggestion that even at these wavelengths there is a significant contribution from this thermal emission process (Witt, Schild, and Kraiman, 1984). If the nebula is seen by reflected starlight then this radiation will be linearly polarized. The level of polarization depends on the scattering geometry, grain size distribution, etc., and is typically 20 to 40 percent for nebulae such as NGC 1999 which is morphologically similar to NGC 2023. If, in any waveband, there is a contribution of radiation from emission processes this radiation will be unpolarized and will serve to dilute the scattered radiation to give a lower level of observed polarization. A study of the wavelength dependence of polarization in nebulae in which there may be thermal emission from grains will indicate the contribution from this process to the total luminosity. Polarization maps were produced in BVRI wavebands for the NGC 2023 nebulosity which confirm that at all wavelengths it is a reflection nebula illuminated by a central star. The wavelength dependence of polarization at representative points in the nebula and in a scatter plot of polarization in V and I wavebands at all points at which measurements are given. Results indicate that throughout the nebula there is a general trend for the level of polarization to increase with wavelength and that maximum levels of polarization occur at the longest wavelengths. No evidence is seen in the data for any significant contribution from the thermal emission from grains in the BVRI luminosity of NGC 2023

  13. Estimates of SASE power in the short wavelength region

    International Nuclear Information System (INIS)

    Kim, Kwang-Je.

    1992-03-01

    Given a sufficiently bright electron beam, the self-amplified-spontaneous emission (SASE) can provide gigawatts of short wavelength coherent radiation. The advantages of SASE approach are that is requires neither optical cavity nor an imput seed laser. In this note, we estimate the peak power performance of SASE for wavelengths shorter than 1000 Angstrom. At each wavelength, we calculate the saturated power from a uniform parameter undulator and the enhanced power from a tapered undulator. The method described here is an adaptation of that discussed by L.H. Yu, who discussed the harmonic generation scheme with seeded laser, to the case of SASE

  14. Full phosphorescent white-light organic light-emitting diodes with improved color stability and efficiency by fine tuning primary emission contributions

    Directory of Open Access Journals (Sweden)

    Wang Hua

    2014-02-01

    Full Text Available In this paper, a novel type of white-light organic light emitting diode (OLED with high color stability was reported, in which the yellow-light emission layer of (4,4′-N,N′-dicarbazolebiphenyl (CBP : tris(2-phenylquinoline-C2,N′iridium(III (Ir(2-phq3 was sandwiched by double blue-light emission layers of 1,1-bis-[(di-4-tolylaminopheny1]cyclohexane (TAPC : bis[4,6-(di-fluorophenyl-pyridinato-N,C2′]picolinate (FIrpic and tris[3-(3-pyridylmesityl]borane (3TPYMB:FIrpic. And, it exhibited the maximum current efficiency of 33.1 cd/A, the turn-on voltage at about 3 V and the maximum luminance in excess of 20000 cd/m2. More important, it realized very stable white-light emission, and its CIE(x, y coordinates only shift from (0.34, 0.37 to (0.33, 0.37 as applied voltage increased from 5 V to 12 V. It is believed that the new scheme in emission layer of white-light OLED can fine tune the contribution of primary emission with applied voltage changed, resulting in high quality white-light OLED.

  15. Full phosphorescent white-light organic light-emitting diodes with improved color stability and efficiency by fine tuning primary emission contributions

    Energy Technology Data Exchange (ETDEWEB)

    Hua, Wang, E-mail: wmsu2008@sinano.ac.cn, E-mail: wanghua001@tyut.edu.cn; Du, Xiaogang [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan 030024 (China); Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Su, Wenming, E-mail: wmsu2008@sinano.ac.cn, E-mail: wanghua001@tyut.edu.cn; Zhang, Dongyu [Printable Electronics Research Centre, Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, suzhou 215123 (China); Lin, Wenjing [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan 030024 (China); Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Printable Electronics Research Centre, Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, suzhou 215123 (China)

    2014-02-15

    In this paper, a novel type of white-light organic light emitting diode (OLED) with high color stability was reported, in which the yellow-light emission layer of (4,4{sup ′}-N,N{sup ′}-dicarbazole)biphenyl (CBP) : tris(2-phenylquinoline-C2,N{sup ′})iridium(III) (Ir(2-phq){sub 3}) was sandwiched by double blue-light emission layers of 1,1-bis-[(di-4-tolylamino)pheny1]cyclohexane (TAPC) : bis[4,6-(di-fluorophenyl)-pyridinato-N,C2{sup ′}]picolinate (FIrpic) and tris[3-(3-pyridyl)mesityl]borane (3TPYMB):FIrpic. And, it exhibited the maximum current efficiency of 33.1 cd/A, the turn-on voltage at about 3 V and the maximum luminance in excess of 20000 cd/m{sup 2}. More important, it realized very stable white-light emission, and its CIE(x, y) coordinates only shift from (0.34, 0.37) to (0.33, 0.37) as applied voltage increased from 5 V to 12 V. It is believed that the new scheme in emission layer of white-light OLED can fine tune the contribution of primary emission with applied voltage changed, resulting in high quality white-light OLED.

  16. Full phosphorescent white-light organic light-emitting diodes with improved color stability and efficiency by fine tuning primary emission contributions

    Science.gov (United States)

    Hua, Wang; Du, Xiaogang; Su, Wenming; Lin, Wenjing; Zhang, Dongyu

    2014-02-01

    In this paper, a novel type of white-light organic light emitting diode (OLED) with high color stability was reported, in which the yellow-light emission layer of (4,4'-N,N'-dicarbazole)biphenyl (CBP) : tris(2-phenylquinoline-C2,N')iridium(III) (Ir(2-phq)3) was sandwiched by double blue-light emission layers of 1,1-bis-[(di-4-tolylamino)pheny1]cyclohexane (TAPC) : bis[4,6-(di-fluorophenyl)-pyridinato-N,C2']picolinate (FIrpic) and tris[3-(3-pyridyl)mesityl]borane (3TPYMB):FIrpic. And, it exhibited the maximum current efficiency of 33.1 cd/A, the turn-on voltage at about 3 V and the maximum luminance in excess of 20000 cd/m2. More important, it realized very stable white-light emission, and its CIE(x, y) coordinates only shift from (0.34, 0.37) to (0.33, 0.37) as applied voltage increased from 5 V to 12 V. It is believed that the new scheme in emission layer of white-light OLED can fine tune the contribution of primary emission with applied voltage changed, resulting in high quality white-light OLED.

  17. Empirical analysis of the effect of descent flight path angle on primary gaseous emissions of commercial aircraft.

    Science.gov (United States)

    Turgut, Enis T; Usanmaz, Oznur; Rosen, Marc A

    2018-05-01

    In this study, the effects of descent flight path angle (between 1.25° and 4.25°) on aircraft gaseous emissions (carbon monoxide, total hydrocarbons and nitrogen oxides) are explored using actual flight data from aircraft flight data recording system and emissions indices from the International Civil Aviation Organization. All emissions parameters are corrected to flight conditions using Boeing Fuel Flow Method2, where the ambient air pressure, temperature and humidity data are obtained from long-term radiosonde data measured close to the arrival airport. The main findings highlight that the higher the flight path angle, the higher the emission indices of CO and HC, whereas the lower the emissions index of NO x and fuel consumption. Furthermore, during a descent, a heavier aircraft tends to emit less CO and HC, and more NO x . For a five-tonne aircraft mass increase, the average change in emissions indices are found to be -4.1% and -5.7% (CO), -5.4% and -8.2% (HC), and +1.1% and +1.6% (NO x ) for high and low flight path angle groups, respectively. The average emissions indices for CO, HC and NO x during descent are calculated to be 24.5, 1.7 and 5.6 g/kg of fuel, whereas the average emissions for descending from 32,000 ft (9.7 km) and 24,000 ft (7.3 km) are calculated to be 7-8 kg (CO), ∼0.5 kg (HC) and ∼3 kg (NO x ). Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Converting a Monopole Emission into a Dipole Using a Subwavelength Structure

    Science.gov (United States)

    Fan, Xu-Dong; Zhu, Yi-Fan; Liang, Bin; Cheng, Jian-chun; Zhang, Likun

    2018-03-01

    High-efficiency emission of multipoles is unachievable by a source much smaller than the wavelength, preventing compact acoustic devices for generating directional sound beams. Here, we present a primary scheme towards solving this problem by numerically and experimentally enclosing a monopole sound source in a structure with a dimension of around 1 /10 sound wavelength to emit a dipolar field. The radiated sound power is found to be more than twice that of a bare dipole. Our study of efficient emission of directional low-frequency sound from a monopole source in a subwavelength space may have applications such as focused ultrasound for imaging, directional underwater sound beams, miniaturized sonar, etc.

  19. Forest biomass supply chains in Ireland: A life cycle assessment of GHG emissions and primary energy balances

    International Nuclear Information System (INIS)

    Murphy, Fionnuala; Devlin, Ger; McDonnell, Kevin

    2014-01-01

    Highlights: • Wood energy supply chains are analysed for energy requirements and GHG emissions. • Use of residues and stumps for energy is evaluated for Irish conditions. • Results highlight transportation as the most energy and GHG emission intensive step. • Wood energy compares favourably with other biomass sources and fossil fuels. - Abstract: The demand for wood for energy production in Ireland is predicted to double from 1.5 million m 3 over bark (OB) in 2011 to 3 million m 3 OB by 2020. There is a large potential for additional biomass recovery for energetic purposes from both thinning forest stands and by harvesting of tops and branches, and stumps. This study builds on research within the wood-for-energy concept in Ireland by analysing the energy requirements and greenhouse gas emissions associated with thinning, residue bundling and stump removal for energy purposes. To date there have been no studies on harvesting of residues and stumps in terms of energy balances and greenhouse gas emissions across the life cycle in Ireland. The results of the analysis on wood energy supply chains highlights transport as the most energy and greenhouse gas emissions intensive step in the life cycle. This finding illustrates importance of localised production and use of forest biomass. Production of wood chip, and shredded bundles and stumps, compares favourably with both other sources of biomass in Ireland and fossil fuels

  20. Future premature mortality due to O3, secondary inorganic aerosols and primary PM in Europe--sensitivity to changes in climate, anthropogenic emissions, population and building stock.

    Science.gov (United States)

    Geels, Camilla; Andersson, Camilla; Hänninen, Otto; Lansø, Anne Sofie; Schwarze, Per E; Skjøth, Carsten Ambelas; Brandt, Jørgen

    2015-03-04

    Air pollution is an important environmental factor associated with health impacts in Europe and considerable resources are used to reduce exposure to air pollution through emission reductions. These reductions will have non-linear effects on exposure due, e.g., to interactions between climate and atmospheric chemistry. By using an integrated assessment model, we quantify the effect of changes in climate, emissions and population demography on exposure and health impacts in Europe. The sensitivity to the changes is assessed by investigating the differences between the decades 2000-2009, 2050-2059 and 2080-2089. We focus on the number of premature deaths related to atmospheric ozone, Secondary Inorganic Aerosols and primary PM. For the Nordic region we furthermore include a projection on how population exposure might develop due to changes in building stock with increased energy efficiency. Reductions in emissions cause a large significant decrease in mortality, while climate effects on chemistry and emissions only affects premature mortality by a few percent. Changes in population demography lead to a larger relative increase in chronic mortality than the relative increase in population. Finally, the projected changes in building stock and infiltration rates in the Nordic indicate that this factor may be very important for assessments of population exposure in the future.

  1. Future Premature Mortality Due to O3, Secondary Inorganic Aerosols and Primary PM in Europe — Sensitivity to Changes in Climate, Anthropogenic Emissions, Population and Building Stock

    Science.gov (United States)

    Geels, Camilla; Andersson, Camilla; Hänninen, Otto; Lansø, Anne Sofie; Schwarze, Per E.; Ambelas Skjøth, Carsten; Brandt, Jørgen

    2015-01-01

    Air pollution is an important environmental factor associated with health impacts in Europe and considerable resources are used to reduce exposure to air pollution through emission reductions. These reductions will have non-linear effects on exposure due, e.g., to interactions between climate and atmospheric chemistry. By using an integrated assessment model, we quantify the effect of changes in climate, emissions and population demography on exposure and health impacts in Europe. The sensitivity to the changes is assessed by investigating the differences between the decades 2000–2009, 2050–2059 and 2080–2089. We focus on the number of premature deaths related to atmospheric ozone, Secondary Inorganic Aerosols and primary PM. For the Nordic region we furthermore include a projection on how population exposure might develop due to changes in building stock with increased energy efficiency. Reductions in emissions cause a large significant decrease in mortality, while climate effects on chemistry and emissions only affects premature mortality by a few percent. Changes in population demography lead to a larger relative increase in chronic mortality than the relative increase in population. Finally, the projected changes in building stock and infiltration rates in the Nordic indicate that this factor may be very important for assessments of population exposure in the future. PMID:25749320

  2. Future Premature Mortality Due to O3, Secondary Inorganic Aerosols and Primary PM in Europe — Sensitivity to Changes in Climate, Anthropogenic Emissions, Population and Building Stock

    Directory of Open Access Journals (Sweden)

    Camilla Geels

    2015-03-01

    Full Text Available Air pollution is an important environmental factor associated with health impacts in Europe and considerable resources are used to reduce exposure to air pollution through emission reductions. These reductions will have non-linear effects on exposure due, e.g., to interactions between climate and atmospheric chemistry. By using an integrated assessment model, we quantify the effect of changes in climate, emissions and population demography on exposure and health impacts in Europe. The sensitivity to the changes is assessed by investigating the differences between the decades 2000–2009, 2050–2059 and 2080–2089. We focus on the number of premature deaths related to atmospheric ozone, Secondary Inorganic Aerosols and primary PM. For the Nordic region we furthermore include a projection on how population exposure might develop due to changes in building stock with increased energy efficiency. Reductions in emissions cause a large significant decrease in mortality, while climate effects on chemistry and emissions only affects premature mortality by a few percent. Changes in population demography lead to a larger relative increase in chronic mortality than the relative increase in population. Finally, the projected changes in building stock and infiltration rates in the Nordic indicate that this factor may be very important for assessments of population exposure in the future.

  3. Topology optimised wavelength dependent splitters

    DEFF Research Database (Denmark)

    Hede, K. K.; Burgos Leon, J.; Frandsen, Lars Hagedorn

    A photonic crystal wavelength dependent splitter has been constructed by utilising topology optimisation1. The splitter has been fabricated in a silicon-on-insulator material (Fig. 1). The topology optimised wavelength dependent splitter demonstrates promising 3D FDTD simulation results....... This complex photonic crystal structure is very sensitive against small fabrication variations from the expected topology optimised design. A wavelength dependent splitter is an important basic building block for high-performance nanophotonic circuits. 1J. S. Jensen and O. Sigmund, App. Phys. Lett. 84, 2022...

  4. AWG Filter for Wavelength Interrogator

    Science.gov (United States)

    Black, Richard J. (Inventor); Costa, Joannes M. (Inventor); Faridian, Fereydoun (Inventor); Moslehi, Behzad (Inventor); Sotoudeh, Vahid (Inventor)

    2015-01-01

    A wavelength interrogator is coupled to a circulator which couples optical energy from a broadband source to an optical fiber having a plurality of sensors, each sensor reflecting optical energy at a unique wavelength and directing the reflected optical energy to an AWG. The AWG has a detector coupled to each output, and the reflected optical energy from each grating is coupled to the skirt edge response of the AWG such that the adjacent channel responses form a complementary pair response. The complementary pair response is used to convert an AWG skirt response to a wavelength.

  5. Dye mixtures for ultrafast wavelength shifters

    Energy Technology Data Exchange (ETDEWEB)

    Gangopadhyay, S.; Liu, L.; Palsule, C.; Borst, W.; Wigmans, R. [Texas Tech Univ., Lubbock, TX (United States). Dept. of Physics; Barashkov, N. [Karpov Inst. of Physical Chemistry, Moscow (Russian Federation)

    1994-12-31

    Particle detectors based on scintillation processes have been used since the discovery of radium about 100 years ago. The fast signals that can be obtained with these detectors, although often considered a nice asset, were rarely essential for the success of experiments. However, the new generation of high energy particle accelerators require particle detectors with fast response time. The authors have produced fast wavelength shifters using mixtures of various Coumarin dyes with DCM in epoxy-polymers (DGEBA+HHPA) and measured the properties of these wavelength shifters. The particular mixtures were chosen because there is a substantial overlap between the emission spectrum of Coumarin and the absorption spectrum of DCM. The continuous wave and time-resolved fluorescence spectra have been studied as a function of component concentration to optimize the decay times, emission peaks and quantum yields. The mean decay times of these mixtures are in the range of 2.5--4.5 ns. The mean decay time increases with an increase in Coumarin concentration at a fixed DCM concentration or with a decrease in DCM concentration at a fixed Coumarin concentration. This indicates that the energy transfer is radiative at lower relative DCM concentrations and becomes non-radiative at higher DCM concentrations.

  6. Dye mixtures for ultrafast wavelength shifters

    International Nuclear Information System (INIS)

    Gangopadhyay, S.; Liu, L.; Palsule, C.; Borst, W.; Wigmans, R.

    1994-01-01

    Particle detectors based on scintillation processes have been used since the discovery of radium about 100 years ago. The fast signals that can be obtained with these detectors, although often considered a nice asset, were rarely essential for the success of experiments. However, the new generation of high energy particle accelerators require particle detectors with fast response time. The authors have produced fast wavelength shifters using mixtures of various Coumarin dyes with DCM in epoxy-polymers (DGEBA+HHPA) and measured the properties of these wavelength shifters. The particular mixtures were chosen because there is a substantial overlap between the emission spectrum of Coumarin and the absorption spectrum of DCM. The continuous wave and time-resolved fluorescence spectra have been studied as a function of component concentration to optimize the decay times, emission peaks and quantum yields. The mean decay times of these mixtures are in the range of 2.5--4.5 ns. The mean decay time increases with an increase in Coumarin concentration at a fixed DCM concentration or with a decrease in DCM concentration at a fixed Coumarin concentration. This indicates that the energy transfer is radiative at lower relative DCM concentrations and becomes non-radiative at higher DCM concentrations

  7. Positron Emission Tomography/Magnetic Resonance Imaging for Local Tumor Staging in Patients With Primary Breast Cancer: A Comparison With Positron Emission Tomography/Computed Tomography and Magnetic Resonance Imaging.

    Science.gov (United States)

    Grueneisen, Johannes; Nagarajah, James; Buchbender, Christian; Hoffmann, Oliver; Schaarschmidt, Benedikt Michael; Poeppel, Thorsten; Forsting, Michael; Quick, Harald H; Umutlu, Lale; Kinner, Sonja

    2015-08-01

    This study aimed to assess the diagnostic performance of integrated positron emission tomography (PET)/magnetic resonance imaging (MRI) of the breast for lesion detection and local tumor staging of patients with primary breast cancer in comparison to PET/computed tomography (CT) and MRI. The study was approved by the local institutional review board. Forty-nine patients with biopsy-proven invasive breast cancer were prospectively enrolled in our study. All patients underwent a PET/CT, and subsequently, a contrast-enhanced PET/MRI of the breast after written informed consent was obtained before each examination. Two radiologists independently evaluated the corresponding data sets (PET/CT, PET/MRI, and MRI) and were instructed to identify primary tumors lesions as well as multifocal/multicentric and bilateral disease. Furthermore, the occurrence of lymph node metastases was assessed, and the T-stage for each patient was determined. Histopathological verification of the local tumor extent and the axillary lymph node status was available for 30 of 49 and 48 of 49 patients, respectively. For the remaining patients, a consensus characterization was performed for the determination of the T-stage and nodal status, taking into account the results of clinical staging, PET/CT, and PET/MRI examinations. Statistical analysis was performed to test for differences in diagnostic performance between the different imaging procedures. P values less than 0.05 were considered to be statistically significant. Positron emission tomography/MRI and MRI correctly identified 47 (96%) of the 49 patients with primary breast cancer, whereas PET/CT enabled detection of 46 (94%) of 49 breast cancer patients and missed a synchronous carcinoma in the contralateral breast in 1 patient. In a lesion-by-lesion analysis, no significant differences could be obtained between the 3 imaging procedures for the identification of primary breast cancer lesions (P > 0.05). Positron emission tomography/MRI and

  8. Towards short wavelengths FELs workshop

    International Nuclear Information System (INIS)

    Ben-Zvi, I.; Winick, H.

    1993-01-01

    This workshop was caged because of the growing perception in the FEL source community that recent advances have made it possible to extend FEL operation to wavelengths about two orders of magnitude shorter than the 240 nm that has been achieved to date. In addition short wavelength FELs offer the possibilities of extremely high peak power (several gigawatts) and very short pulses (of the order of 100 fs). Several groups in the USA are developing plans for such short wavelength FEL facilities. However, reviewers of these plans have pointed out that it would be highly desirable to first carry out proof-of-principle experiments at longer wavelengths to increase confidence that the shorter wavelength devices will indeed perform as calculated. The need for such experiments has now been broadly accepted by the FEL community. Such experiments were the main focus of this workshop as described in the following objectives distributed to attendees: (1) Define measurements needed to gain confidence that short wavelength FELs will perform as calculated. (2) List possible hardware that could be used to carry out these measurements in the near term. (3) Define a prioritized FEL physics experimental program and suggested timetable. (4) Form collaborative teams to carry out this program

  9. Towards short wavelengths FELs workshop

    Science.gov (United States)

    Ben-Zvi, I.; Winick, H.

    1993-11-01

    This workshop was caged because of the growing perception in the FEL source community that recent advances have made it possible to extend FEL operation to wavelengths about two orders of magnitude shorter than the 240 nm that has been achieved to date. In addition short wavelength FEL's offer the possibilities of extremely high peak power (several gigawatts) and very short pulses (of the order of 100 fs). Several groups in the USA are developing plans for such short wavelength FEL facilities. However, reviewers of these plans have pointed out that it would be highly desirable to first carry out proof-of-principle experiments at longer wavelengths to increase confidence that the shorter wavelength devices will indeed perform as calculated. The need for such experiments has now been broadly accepted by the FEL community. Such experiments were the main focus of this workshop as described in the following objectives distributed to attendees: (1) Define measurements needed to gain confidence that short wavelength FEL's will perform as calculated. (2) List possible hardware that could be used to carry out these measurements in the near term. (3) Define a prioritized FEL physics experimental program and suggested timetable. (4) Form collaborative teams to carry out this program.

  10. 18F-FDG whole body positron emission tomography (PET) in patients with unknown primary tumours (UPT)

    DEFF Research Database (Denmark)

    Lassen, U; Daugaard, G; Eigtved, A

    1999-01-01

    adenocarcinomas and 1 poorly differentiated carcinoma). The remaining patients had metastases located in bone (3), bone marrow (1), brain (1), pericardium (1), skin (1), pleura (1) and chest wall (1). All metastatic lesions were visible with PET. In 13 patients PET suggested the site for the primary tumour...... by the PET result. The rest received either radical radiotherapy to the head and neck region (7), palliative radiotherapy to the metastatic lesion (8), chemotherapy based on signet ring cell carcinoma in bone marrow (1) or no therapy (1). These results indicates that PET is useful in UPT preceding expensive......The management of patients with unknown primary tumours (UPT) often includes a large number of radiographical studies and invasive procedures, but the occult primary tumour is detected in less than 25%. In this prospective study we explored whether non-invasive whole body PET scans using FDG (18-F...

  11. 18F-FDG whole body positron emission tomography (PET) in patients with unknown primary tumours (UPT)

    DEFF Research Database (Denmark)

    Lassen, U; Daugaard, G; Eigtved, A

    1999-01-01

    -fluorodeoxyglucose) are of clinical value in detection of UPT. Whole-body FDG-PET scans were performed in 20 patients following standard staging procedures according to histology. PET results were verified either histologically or by the clinical course of the disease. 11 patients had neck metastases (5 squamous cell, 5......The management of patients with unknown primary tumours (UPT) often includes a large number of radiographical studies and invasive procedures, but the occult primary tumour is detected in less than 25%. In this prospective study we explored whether non-invasive whole body PET scans using FDG (18-F...... and this was verified in 9 (45%), either histologically or by the clinical course of disease. 8 of these had primary lung cancer and 1 had carcinoma at the basis of the tongue. In most patients PET had no treatment related implications. 3 patients with non-small cell lung cancer (NSCLC) received chemotherapy prompted...

  12. What is the value of emission tomography studies in patients with a primary glioblastoma multiforme treated by {sup 192}Ir brachytherapy?

    Energy Technology Data Exchange (ETDEWEB)

    Koot, R W; Bosch, D A [Academic Medical Center, Department of Neurosurgery, University of Amsterdam, Amsterdam (Netherlands); Habraken, J B.A. [Academic Medical Center, Department of Nuclear Medicine, University of Amsterdam, Amsterdam (Netherlands); Academic Medical Center, Department of Radiology, University of Amsterdam, Amsterdam (Netherlands); Hulshof, M C.C.M. [Academic Medical Center, Department of Radiotherapy, University of Amsterdam, Amsterdam (Netherlands); Paans, A M.J.; Pruim, J. [Department of Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, Groningen (Netherlands)], e-mail: r.w.koot@lumc.nl

    2008-07-01

    We studied the use of {sup 201}thallium SPECT and L-[1-{sup 11}C]-tyrosine PET in patients with a primary glioblastoma multiforme treated with {sup 192}Ir brachytherapy after surgery and external beam radiation therapy. We hypothesised that the patients most likely to benefit from further surgery after deterioration would be those with radiation necrosis and would be recognised by a negative emission tomography scan. Twenty-one patients underwent {sup 201}thallium SPECT performed before brachytherapy, and this was repeated in 19 patients when recurrence was suspected. Nine patients also underwent a PET scan at the same time. Nine patients underwent a second operation. SPECT and PET were highly concordant concerning the prediction of radionecrosis and/or tumor recurrence. Repeat surgery did not lead to a significant increase in survival. There was no significant association between the duration of survival and tumor-to-background ratio but the number studied was small. Both SPECT and PET showed highly active lesions, which were proved to be recurrent tumor by clinical and histological follow-up. Although PET and SPECT are both highly sensitive in detecting active tumor tissue, emission tomography was not clinically valuable in the investigation of patients with a primary glioblastoma treated with brachytherapy. (author)

  13. Local emission of primary air pollutants and its contribution to wet deposition and concentrations of aerosols and gases in ambient air in Japan

    Science.gov (United States)

    Aikawa, Masahide; Hiraki, Takatoshi; Tomoyose, Nobutaka; Ohizumi, Tsuyoshi; Noguchi, Izumi; Murano, Kentaro; Mukai, Hitoshi

    2013-11-01

    We studied wet deposition by precipitation and the concentrations of aerosols and gases in ambient air in relation to the primary air pollutants discharged from domestic areas. The concentrations of aerosols and gases were influenced by nearby emissions except for non-sea-salt SO, which is transported long distances. The area facing the Sea of Japan showed much larger wet deposition than other areas, although the domestic emissions of the primary air pollutants there were small and showed a peak in wet deposition from October to March, as distinct from April to September in other areas. We performed the correlation analyses between wet deposition of each component and the product of the concentrations of corresponding aerosols and gases in ambient air and the two-thirds power of the precipitation. From the results, following scavenging processes were suggested. • Sulfate and ammonium were scavenged in precipitation as particulate matter such as (NH4)2SO4 and NH4HSO4. • Nitrate was scavenged mainly in precipitation through gaseous HNO3. • Ammonium was complementarily scavenged in precipitation through aerosols such as (NH4)2SO4 and NH4HSO4 and through gaseous NH3.

  14. Ghostly Glow Reveals a Hidden Class of Long-Wavelength Radio Emitters

    Science.gov (United States)

    2008-10-01

    (Washington, DC. 08)- A team of scientists, including astronomers from the Naval Research Laboratory (NRL), have detected long wavelength radio emission from a colliding, massive galaxy cluster which, surprisingly, is not detected at the shorter wavelengths typically seen in these objects. The discovery implies that existing radio telescopes have missed a large population of these colliding objects. It also provides an important confirmation of the theoretical prediction that colliding galaxy clusters accelerate electrons and other particles to very high energies through the process of turbulent waves. The team revealed their findings in the October 16, 2008 edition of Nature. This new population of objects is most easily detected at long wavelengths. Professor Greg Taylor of the University of New Mexico and scientific director of the Long Wavelength Array (LWA) points out, "This result is just the tip of the iceberg. When an emerging suite of much more powerful low frequency telescopes, including the LWA in New Mexico, turn their views to the cosmos, the sky will 'light up' with hundreds or even thousands of colliding galaxy clusters." NRL has played a key role in promoting the development of this generation of new instruments and is currently involved with the development of the LWA. NRL radio astronomer and LWA Project Scientist Namir Kassim says "Our discovery of a previously hidden class of low frequency cluster-radio sources is particularly important since the study of galaxy clusters was a primary motivation for development of the LWA." The discovery of the emission in the galaxy cluster Abell 521 (or A521 for short) was made using the Giant Metrewave Radiotelescope (GMRT) in India, and its long wavelength nature was confirmed by the National Science Foundation's (NRAO) Very Large Array (VLA) radio telescope in New Mexico. The attached image shows the radio emission at a wavelength of 125cm in red superimposed on a blue image made from data taken by the

  15. Characterization of primary organic aerosol emissions from meat cooking, trash burning, and motor vehicles with high-resolution aerosol mass spectrometry and comparison with ambient and chamber observations.

    Science.gov (United States)

    Mohr, Claudia; Huffman, Alex; Cubison, Michael J; Aiken, Allison C; Docherty, Kenneth S; Kimmel, Joel R; Ulbrich, Ingrid M; Hannigan, Michael; Jimenez, Jose L

    2009-04-01

    Organic aerosol (OA) emissions from motor vehicles, meat-cooking and trash burning are analyzed here using a high-resolution aerosol mass spectrometer (AMS). High resolution data show that aerosols emitted by combustion engines and plastic burning are dominated by hydrocarbon-like organic compounds. Meat cooking and especially paper burning emissions contain significant fractions of oxygenated organic compounds; however, their unit-resolution mass spectral signatures are very similar to those from ambient hydrocarbon-like OA, and very different from the mass spectra of ambient secondary or oxygenated OA (OOA). Thus, primary OA from these sources is unlikelyto be a significant direct source of ambient OOA. There are significant differences in high-resolution tracer m/zs that may be useful for differentiating some of these sources. Unlike in most ambient spectra, all of these sources have low total m/z 44 and this signal is not dominated by the CO2+ ion. All sources have high m/z 57, which is low during high OOA ambient periods. Spectra from paper burning are similar to some types of biomass burning OA, with elevated m/z 60. Meat cooking aerosols also have slightly elevated m/z 60, whereas motor vehicle emissions have very low signal at this m/z.

  16. Are perfluoroalkyl acids in waste water treatment plant effluents the result of primary emissions from the technosphere or of environmental recirculation?

    Science.gov (United States)

    Filipovic, Marko; Berger, Urs

    2015-06-01

    Wastewater treatment plants (WWTP) have been suggested to be one of the major pathways of perfluoroalkyl acids (PFAAs) from the technosphere to the aquatic environment. The origin of PFAAs in WWTP influents is either from current primary emissions or a result of recirculation of PFAAs that have been residing and transported in the environment for several years or decades. Environmental recirculation can then occur when PFAAs from the environment enter the wastewater stream in, e.g., tap water. In this study 13 PFAAs and perfluorooctane sulfonamide were analyzed in tap water as well as WWTP influent, effluent and sludge from three Swedish cities: Bromma (in the metropolitan area of Stockholm), Bollebygd and Umeå. A mass balance of the WWTPs was assembled for each PFAA. Positive mass balances were observed for PFHxA and PFOA in all WWTPs, indicating the presence of precursor compounds in the technosphere. With regard to environmental recirculation, tap water was an important source of PFAAs to the Bromma WWTP influent, contributing >40% for each quantified sulfonic acid and up to 30% for the carboxylic acids. The PFAAs in tap water from Bollebygd and Umeå did not contribute significantly to the PFAA load in the WWTP influents. Our results show that in order to estimate current primary emissions from the technosphere, it may be necessary to correct the PFAA emission rates in WWTP effluents for PFAAs present in tap water, especially in the case of elevated levels in tap water. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Wavelength dependence of interstellar polarization

    International Nuclear Information System (INIS)

    Mavko, G.E.

    1974-01-01

    The wavelength dependence of interstellar polarization was measured for twelve stars in three regions of the Milky Way. A 120A bandpass was used to measure the polarization at a maximum of sixteen wavelengths evenly spaced between 2.78μ -1 (3600A) and 1.28μ -1 (7800A). For such a wide wavelength range, the wavelength resolution is superior to that of any previously reported polarization measurements. The new scanning polarimeter built by W. A. Hiltner of the University of Michigan was used for the observations. Very broad structure was found in the wavelength dependence of the polarization. Extensive investigations were carried out to show that the structure was not caused by instrumental effects. The broad structure observed is shown to be in agreement with concurrent extinction measurements for the same stars. Also, the observed structure is of the type predicted when a homogeneous silicate grain model is fitted to the observed extinction. The results are in agreement with the hypothesis that the very broad band structure seen in the extinction is produced by the grains. (Diss. Abstr. Int., B)

  18. Recent Warming, Rather than Industrial Emissions of Bioavailable Nutrients, Is the Dominant Driver of Lake Primary Production Shifts across the Athabasca Oil Sands Region.

    Directory of Open Access Journals (Sweden)

    Jamie C Summers

    Full Text Available Freshwaters in the Athabasca Oil Sands Region (AOSR are vulnerable to the atmospheric emissions and land disturbances caused by the local oil sands industry; however, they are also affected by climate change. Recent observations of increases in aquatic primary production near the main development area have prompted questions about the principal drivers of these limnological changes. Is the enhanced primary production due to deposition of nutrients (nitrogen and phosphorus from local industry or from recent climatic changes? Here, we use downcore, spectrally-inferred chlorophyll-a (VRS-chla profiles (including diagenetic products from 23 limnologically-diverse lakes with undisturbed catchments to characterize the pattern of primary production increases in the AOSR. Our aim is to better understand the relative roles of the local oil sands industry versus climate change in driving aquatic primary production trends. Nutrient deposition maps, generated using geostatistical interpolations of spring-time snowpack measurements from a grid pattern across the AOSR, demonstrate patterns of elevated total phosphorus, total nitrogen, and bioavailable nitrogen deposition around the main area of industrial activity. However, this pattern is not observed for bioavailable phosphorus. Our paleolimnological findings demonstrate consistently greater VRS-chla concentrations compared to pre-oil sands development levels, regardless of morphological and limnological characteristics, landscape position, bioavailable nutrient deposition, and dibenzothiophene (DBT-inferred industrial impacts. Furthermore, breakpoint analyses on VRS-chla concentrations across a gradient of DBT-inferred industrial impact show limited evidence of a contemporaneous change among lakes. Despite the contribution of bioavailable nitrogen to the landscape from industrial activities, we find no consistency in the spatial pattern and timing of VRS-chla shifts with an industrial fertilizing signal

  19. Selection of Quantum Dot Wavelengths for Biomedical Assays and Imaging

    Directory of Open Access Journals (Sweden)

    Yong Taik Lim

    2003-01-01

    Full Text Available Fluorescent semiconductor nanocrystals (quantum dots [QDs] are hypothesized to be excellent contrast agents for biomedical assays and imaging. A unique property of QDs is that their absorbance increases with increasing separation between excitation and emission wavelengths. Much of the enthusiasm for using QDs in vivo stems from this property, since photon yield should be proportional to the integral of the broadband absorption. In this study, we demonstrate that tissue scatter and absorbance can sometimes offset increasing QD absorption at bluer wavelengths, and counteract this potential advantage. By using a previously validated mathematical model, we explored the effects of tissue absorbance, tissue scatter, wavelength dependence of the scatter, water-to- hemoglobin ratio, and tissue thickness on QD performance. We conclude that when embedded in biological fluids and tissues, QD excitation wavelengths will often be quite constrained, and that excitation and emission wavelengths should be selected carefully based on the particular application. Based on our results, we produced near-infrared QDs optimized for imaging surface vasculature with white light excitation and a silicon CCD camera, and used them to image the coronary vasculature in vivo. Taken together, our data should prove useful in designing fluorescent QD contrast agents optimized for specific biomedical applications.

  20. Wavelength conversion techniques and devices

    DEFF Research Database (Denmark)

    Danielsen, Søren Lykke; Mikkelsen, Benny; Hansen, Peter Bukhave

    1997-01-01

    Taking into account the requirements to the converters e.g., bit rate transparency (at least up to 10 Gbit/s), polarisation independence, wavelength independence, moderate input power levels, high signal-to-noise ratio and high extinction ratio interferometric wavelength convertors are very...... interesting for use in WDM optical fibre networks. However, the perfect converter has probably not yet been fabricated and new techniques such as conversion relying on cross-absorption modulation in electro-absorption modulators might also be considered in pursue of effective conversion devices...

  1. Proportion of influence phases anatase and rutile TiO{sub 2} in the photoluminescence 538 nm emission wavelength; Influencia da proporcao das fases anatasio e rutilo na fotoluminescincia do TiO{sub 2} em comprimento de onda de emissao de 538 nm

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, D.S.; Diniz, V.C.S.; Araujo, P.M.A.G.; Costa, A.C.F.M., E-mail: dagobertoufcg@gmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Viana, R.S.; Junior, S.A. [Universidade Federal de Pernambuco (UFPE), PE (Brazil)

    2016-07-01

    TiO2 is one of the most studied materials in the technology area, especially in photoluminescent applications involving catalysts from the biosensor. Therefore, we propose to obtain the Pechini method TiO{sub 2} molar ratio of citric acid/metal ions of 3:1 and 4:1 in order to investigate the influence of the proportion of anatase and rutile phases with the photoluminescence excitation wavelength of 538nm emission. The samples were characterized by X-ray diffraction, thermal analysis and excitation spectroscopy. The results indicate the presence of two phases, with a proportion of 78.99 and 83.58 and 21.01% of anatase and rutile 16.42%, density 3.82 and 3.70 g/cm{sup 3} and excitement in length wave emission 538nm with maximum intensity 91289.2 and 71880,7 cps for samples 3:1 and 4:1, respectively. Sample 3:1 with the highest percentage of rutile phase favored photoluminescence. (author)

  2. Comparison of {sup 18}F-fluorodeoxyglucose positron emission tomography/computed tomography, hydro-stomach computed tomography, and their combination for detecting primary gastric cancer

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Hye Young; Chung, Woo Suk; Song, E Rang; Kim, Jin Suk [Konyang University Myunggok Medical Research Institute, Konyang University Hospital, Konyang University College of Medicine, Daejeon (Korea, Republic of)

    2015-01-15

    To retrospectively compare the diagnostic accuracy for detecting primary gastric cancer on positron emission tomography/computed tomography (PET/CT) and hydro-stomach CT (S-CT) and determine whether the combination of the two techniques improves diagnostic performance. A total of 253 patients with pathologically proven primary gastric cancer underwent PET/CT and S-CT for the preoperative evaluation. Two radiologists independently reviewed the three sets (PET/CT set, S-CT set, and the combined set) of PET/CT and S-CT in a random order. They graded the likelihood for the presence of primary gastric cancer based on a 4-point scale. The diagnostic accuracy of the PET/CT set, the S-CT set, and the combined set were determined by the area under the alternative-free receiver operating characteristic curve, and sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Diagnostic accuracy, sensitivity, and NPV for detecting all gastric cancers and early gastric cancers (EGCs) were significantly higher with the combined set than those with the PET/CT and S-CT sets. Specificity and PPV were significantly higher with the PET/CT set than those with the combined and S-CT set for detecting all gastric cancers and EGCs. The combination of PET/CT and S-CT is more accurate than S-CT alone, particularly for detecting EGCs.

  3. Energy Toolbox—Framework for the Development of a Tool for the Primary Design of Zero Emission Buildings in European and Asian Cities

    Directory of Open Access Journals (Sweden)

    Christoph Koller

    2017-12-01

    Full Text Available This paper discusses the framework for the development of an Energy Toolbox (ETB. The aim of the ETB is to support the design of domestic Zero Emission Buildings (ZEBs, according to the concept of net zero-energy buildings during the early architectural design and planning phases. The ETB concept is based on the calculation of the energy demand for heating, cooling, lighting, and appliances. Based on a building’s energy demand, technologies for the onsite conversion and production of the specific forms and quantities of final and primary energy by means of renewable energy carriers can be identified. The calculations of the ETB are based on the building envelope properties of a primary building design, as well as the physical and climate parameters required for the calculation of heat transfer coefficients, heat gains, and heat losses. The ETB enables the selection and rough dimensioning of technologies and systems to meet, and, wherever possible, reduce the thermal and electric energy demand of a building. The technologies included comprise green facades, adaptable dynamic lighting, shading devices, heat pumps, photovoltaic generators, solar thermal collectors, adiabatic cooling, and thermal storage. The ETB facilitates the balancing of the energy consumption and the production of renewable energies of a primary building design.

  4. Comparison of 18F-fluorodeoxyglucose positron emission tomography/computed tomography, hydro-stomach computed tomography, and their combination for detecting primary gastric cancer

    International Nuclear Information System (INIS)

    Jang, Hye Young; Chung, Woo Suk; Song, E Rang; Kim, Jin Suk

    2015-01-01

    To retrospectively compare the diagnostic accuracy for detecting primary gastric cancer on positron emission tomography/computed tomography (PET/CT) and hydro-stomach CT (S-CT) and determine whether the combination of the two techniques improves diagnostic performance. A total of 253 patients with pathologically proven primary gastric cancer underwent PET/CT and S-CT for the preoperative evaluation. Two radiologists independently reviewed the three sets (PET/CT set, S-CT set, and the combined set) of PET/CT and S-CT in a random order. They graded the likelihood for the presence of primary gastric cancer based on a 4-point scale. The diagnostic accuracy of the PET/CT set, the S-CT set, and the combined set were determined by the area under the alternative-free receiver operating characteristic curve, and sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Diagnostic accuracy, sensitivity, and NPV for detecting all gastric cancers and early gastric cancers (EGCs) were significantly higher with the combined set than those with the PET/CT and S-CT sets. Specificity and PPV were significantly higher with the PET/CT set than those with the combined and S-CT set for detecting all gastric cancers and EGCs. The combination of PET/CT and S-CT is more accurate than S-CT alone, particularly for detecting EGCs.

  5. Wavelength tuning of porous silicon microcavities

    International Nuclear Information System (INIS)

    Mulders, J.; Reece, P.; Zheng, W.H.; Lerondel, G.; Sun, B.; Gal, M.

    2002-01-01

    Full text: In the last decade much attention has been given to porous silicon (PS) for optoelectronic applications, which include efficient room temperature light emission as well as microcavity formation. Due to the large specific surface area, the use of porous silicon microcavities (PSMs) has been proposed for chemical sensing. Large wavelength shifts have indicated that the optical properties of PSMs are indeed strongly dependent on the environment. In this paper, we report the shifting of the resonance frequency of high quality PSMs, with the aim of tuning a future PS device to a certain required wavelength. The PSM samples were prepared by anodically etching p + -doped (5mΩcm) bulk silicon wafer in a solution (25%) of aqueous HF and ethanol. The device structure consisted of a PS layer sandwiched between 2 stacks of thin PS layers with alternating high and low effective refractive indices (RI), i.e. distributed Bragg mirrors (DBM). The layer thickness depends on the etch time while the porosity and hence refractive index is determined by the current density as the Si is etched. The position and the width of the stop-band can be fully controlled by the design of the DBMs, with the microcavity resonance mode sitting within the stop-band. We achieved tuning of the microcavity resonance by a number of methods, including temperature dependent tuning. The temperature induced wavelength shift was found to be of the order of 10 -15 nm. Computer modeling of these changes in the reflectivity spectra allowed us to quantify the changes of the effective refractive index and the respective layer thicknesses

  6. Comparison of the primary energy consumption and the CO2-emission of an urban vehicle with conventional and alternative drives

    International Nuclear Information System (INIS)

    Birnbreier, H.

    1992-01-01

    Based on a model car with its basic data corresponding to those of a series-produced small passenger car, conventional and alternative drives were compared. Cars shared the following features: same basic weight without tank, one energy storage system for the same driving range, same acceleration capacity from 0 to 50 km/h. Petrol and diesel were the conventional fuels; methanol, natural gas (pressurized, liquid), hydrogen (pressurized, liquid, hydride) and electric energy (NaS battery) were the alternative fuels. Both primary energy and CO 2 balancings take the different raw materials into account for the production of useful energies. (orig.) [de

  7. Underdense radiation sources: Moving towards longer wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Back, C.A.; Kilkenny, J.D. [General Atomics, San Diego, California (United States); Seely, J.F.; Weaver, J.L. [Naval Research Laboratory, Washington, DC (United States); Feldman, U. [Artep Inc., Ellicott City, MD (United States); Tommasini, R.; Glendinning, S.G.; Chung, H.K.; Rosen, M.; Lee, R.W.; Scott, H.A. [Lawrence Livermore National Laboratory, California (United States); Tillack, M. [U. C. San Diego, La Jolla, CA (United States)

    2006-06-15

    Underdense radiation sources have been developed to provide efficient laboratory multi-keV radiation sources for radiography and radiation hardening studies. In these plasmas laser absorption by inverse Bremsstrahlung leads to high x-ray conversion efficiency because of efficient ionization of the low density aerogel or gas targets. Now we performing experiments in the soft x-ray energy regime where the atomic physics models are much more complicated. In recent experiments at the NIKE laser, we have irradiated a Ti-doped SiO{sub 2} aerogel with up to 1650 J of 248 nm wavelength light. The absolute Ti L-shell emission in the 200-800 eV range is measured with a diagnostic that uses a transmission grating coupled to Si photodiodes. We will give an overview of the temporally-resolved absolutely calibrated spectra obtained over a range of conditions. (authors)

  8. Underdense radiation sources: Moving towards longer wavelengths

    International Nuclear Information System (INIS)

    Back, C.A.; Kilkenny, J.D.; Seely, J.F.; Weaver, J.L.; Feldman, U.; Tommasini, R.; Glendinning, S.G.; Chung, H.K.; Rosen, M.; Lee, R.W.; Scott, H.A.; Tillack, M.

    2006-01-01

    Underdense radiation sources have been developed to provide efficient laboratory multi-keV radiation sources for radiography and radiation hardening studies. In these plasmas laser absorption by inverse Bremsstrahlung leads to high x-ray conversion efficiency because of efficient ionization of the low density aerogel or gas targets. Now we performing experiments in the soft x-ray energy regime where the atomic physics models are much more complicated. In recent experiments at the NIKE laser, we have irradiated a Ti-doped SiO 2 aerogel with up to 1650 J of 248 nm wavelength light. The absolute Ti L-shell emission in the 200-800 eV range is measured with a diagnostic that uses a transmission grating coupled to Si photodiodes. We will give an overview of the temporally-resolved absolutely calibrated spectra obtained over a range of conditions. (authors)

  9. Intensities of decimetric-wavelength radio recombination lines

    International Nuclear Information System (INIS)

    Parrish, A.; Pankonin, V.

    1975-01-01

    We summarize the intensity results of some of the 221 and 248α recombination-line observations taken with the Arecibo telescope, and report additional results including 166α observations from the NRAO 300-foot (91 m) telescope. The brightness temperatures of these lines increase sharply with wavelength. We show that these results require that the upper levels of the recombining atoms be overpopulated with respect to LTE conditions. The most reasonable interpretation of the results is that the line emission at these decimetric wavelengths is stimulated by a background source of continuum radiation

  10. Vigor of pearl millet seeds by precocity of primary root emissionPrecocidade na emissão da raiz primária para avaliação do vigor de sementes de milheto

    Directory of Open Access Journals (Sweden)

    Simério Carlos Silva Cruz

    2012-05-01

    Full Text Available In a program of seed quality assurance, the evaluation of seed vigor is fundamental and necessary to the global production process outcome. The objective of this study was to evaluate the efficiency of the precocity of primary root emission test, for the substrates paper roll, on paper and between papers, on vigor of pearl millet seeds. Ten seed lots evaluated in four replication of 100 pearl millet seeds cultivar ADR 500 were sown in three different humidified substrates: between papers, paper roll and on paper. These were incubated at a temperature of 20-30°C. Fifteen hours after the germination test was established, the emission of seed primary roots started to be observed every 2 hours up to 25 hours and then after 48 hours. For the comparison among lots, seeds were also evaluated by moisture content, weight of 1000 seeds, germination and vigor (first count, electrical conductivity, accelerated aging and seedling emergence. The statistical design was completely randomized, and the means comparisons were accomplished by the Tukey test at 0.05 level of probability. It was concluded that the precocity of primary root emission test on paper is promising for vigor evaluation of pearl millet seeds. Dentro de um programa de controle de qualidade, a avaliação do vigor de sementes é fundamental e necessária para o sucesso da produção. O objetivo deste estudo foi verificar a eficiência do teste de precocidade da emissão da raiz primária, em três tipos de substrato, na avaliação do vigor de sementes de milheto. Dez lotes de sementes da cultivar ADR 500 foram avaliados mediante a semeadura de quatro repetições de 100 sementes de cada lote em: entre papel, rolo de papel e sobre papel, mantidos sob temperatura alternada de 20-30°C. Após 15 horas as sementes que emitiram a raiz primária foram contadas e descartadas, procedendo-se a leitura a cada 2 horas até 25 horas e posteriormente às 48 horas. Para estabelecer a comparação entre os

  11. Comparison of Amino Acid Positron Emission Tomographic Radiotracers for Molecular Imaging of Primary and Metastatic Brain Tumors

    Directory of Open Access Journals (Sweden)

    Csaba Juhász

    2014-08-01

    Full Text Available Positron emission tomography (PET is an imaging technology that can detect and characterize tumors based on their molecular and biochemical properties, such as altered glucose, nucleoside, or amino acid metabolism. PET plays a significant role in the diagnosis, prognostication, and treatment of various cancers, including brain tumors. In this article, we compare uptake mechanisms and the clinical performance of the amino acid PET radiotracers (L-[methyl-11C]methionine [MET], 18F-fluoroethyl-tyrosine [FET], 18F-fluoro-L- dihydroxy-phenylalanine [FDOPA], and 11C-alpha-methyl-L-tryptophan [AMT] most commonly used for brain tumor imaging. First, we discuss and compare the mechanisms of tumoral transport and accumulation, the basis of differential performance of these radioligands in clinical studies. Then we summarize studies that provided direct comparisons among these amino acid tracers and to clinically used 2-deoxy-2[18F]fluoro-D-glucose [FDG] PET imaging. We also discuss how tracer kinetic analysis can enhance the clinical information obtained from amino acid PET images. We discuss both similarities and differences in potential clinical value for each radioligand. This comparative review can guide which radiotracer to favor in future clinical trials aimed at defining the role of these molecular imaging modalities in the clinical management of brain tumor patients.

  12. Prospective Study of 68Ga-DOTATATE Positron Emission Tomography/Computed Tomography for Detecting Gastro-Entero-Pancreatic Neuroendocrine Tumors and Unknown Primary Sites.

    Science.gov (United States)

    Sadowski, Samira M; Neychev, Vladimir; Millo, Corina; Shih, Joanna; Nilubol, Naris; Herscovitch, Peter; Pacak, Karel; Marx, Stephen J; Kebebew, Electron

    2016-02-20

    Gastro-entero-pancreatic neuroendocrine tumors (GEPNETs) are increasing in incidence, and accurate staging is important for selecting the appropriate treatment. (68)Ga-DOTATATE imaging is a promising approach for detecting GEPNETs and could help in selecting optimal therapeutic strategies. The aim of this study was to prospectively determine the clinical utility of (68)Ga-DOTATATE positron emission tomography (PET)/computed tomography (CT) in detecting unknown primary and metastatic GEPNETs. One hundred thirty-one patients were enrolled in a prospective study of patients undergoing (68)Ga-DOTATATE PET/CT, (111)In-pentetreotide single-photon emission computed tomography (SPECT)/CT and multiphasic CT scan, and/or magnetic resonance imaging in a blinded fashion with comprehensive biochemical testing. The primary outcome measure was the detection of lesions by each imaging study. (68)Ga-DOTATATE PET/CT imaging detected 95.1% of lesions (95% CI, 92.4% to 96.8%) with an average maximum standardized uptake value of 65.4 ± 47 (range, 6.9 to 244), anatomic imaging detected 45.3% of lesions (95% CI, 37.9% to 52.9%), and (111)In-pentetreotide SPECT/CT detected 30.9% of lesions (95% CI, 25.0% to 37.5%), with a significant difference between imaging modalities (P < .001). In four of 14 patients (28.6%), (68)Ga-DOTATATE PET/CT found a previously unknown primary tumor, and detected primary GEPNET, lymph node, and distant metastases correctly in 72 of 113 lesions (63.7%) when compared with histopathology, with 22.1% and 38.9% detected by using (111)In-pentetreotide SPECT/CT and anatomic imaging, respectively. On the basis of findings with (68)Ga-DOTATATE PET/CT, 43 of 131 patients (32.8%) had a change in management recommendation. In patients with carcinoid symptoms but negative biochemical testing, (68)Ga-DOTATATE PET/CT detected lesions in 65.2% of patients, 40% of which were detected neither by anatomic imaging nor by (111)In-pentetreotide SPECT/CT. (68)Ga-DOTATATE PET

  13. Wavelength stabilized multi-kW diode laser systems

    Science.gov (United States)

    Köhler, Bernd; Unger, Andreas; Kindervater, Tobias; Drovs, Simon; Wolf, Paul; Hubrich, Ralf; Beczkowiak, Anna; Auch, Stefan; Müntz, Holger; Biesenbach, Jens

    2015-03-01

    We report on wavelength stabilized high-power diode laser systems with enhanced spectral brightness by means of Volume Holographic Gratings. High-power diode laser modules typically have a relatively broad spectral width of about 3 to 6 nm. In addition the center wavelength shifts by changing the temperature and the driving current, which is obstructive for pumping applications with small absorption bandwidths. Wavelength stabilization of high-power diode laser systems is an important method to increase the efficiency of diode pumped solid-state lasers. It also enables power scaling by dense wavelength multiplexing. To ensure a wide locking range and efficient wavelength stabilization the parameters of the Volume Holographic Grating and the parameters of the diode laser bar have to be adapted carefully. Important parameters are the reflectivity of the Volume Holographic Grating, the reflectivity of the diode laser bar as well as its angular and spectral emission characteristics. In this paper we present detailed data on wavelength stabilized diode laser systems with and without fiber coupling in the spectral range from 634 nm up to 1533 nm. The maximum output power of 2.7 kW was measured for a fiber coupled system (1000 μm, NA 0.22), which was stabilized at a wavelength of 969 nm with a spectral width of only 0.6 nm (90% value). Another example is a narrow line-width diode laser stack, which was stabilized at a wavelength of 1533 nm with a spectral bandwidth below 1 nm and an output power of 835 W.

  14. The Relationship Between Solar Radio and Hard X-Ray Emission

    Science.gov (United States)

    White, S. M.; Benz, A. O.; Christe, S.; Farnik, F.; Kundu, M. R.; Mann, G.; Ning, Z.; Raulin, J.-P.; Silva-Valio, A. V. R.; Saint-Hilaire, P.; hide

    2011-01-01

    This review discusses the complementary relationship between radio and hard Xray observations of the Sun using primarily results from the era of the Reuven Ramaty High Energy Solar Spectroscopic Imager satellite. A primary focus of joint radio and hard X-ray studies of solar flares uses observations of nonthermal gyrosynchrotron emission at radio wavelengths and bremsstrahlung hard X-rays to study the properties of electrons accelerated in the main flare site, since it is well established that these two emissions show very similar temporal behavior. A quantitative prescription is given for comparing the electron energy distributions derived separately from the two wavelength ranges: this is an important application with the potential for measuring the magnetic field strength in the flaring region, and reveals significant differences between the electrons in different energy ranges. Examples of the use of simultaneous data from the two wavelength ranges to derive physical conditions are then discussed, including the case of microflares, and the comparison of images at radio and hard X-ray wavelengths is presented. There have been puzzling results obtained from observations of solar flares at millimeter and submillimeter wavelengths, and the comparison of these results with corresponding hard X-ray data is presented. Finally, the review discusses the association of hard X-ray releases with radio emission at decimeter and meter wavelengths, which is dominated by plasma emission (at lower frequencies) and electron cyclotron maser emission (at higher frequencies), both coherent emission mechanisms that require small numbers of energetic electrons. These comparisons show broad general associations but detailed correspondence remains more elusive.

  15. The primary volcanic aerosol emission from Mt Etna: Size-resolved particles with SO2 and role in plume reactive halogen chemistry

    Science.gov (United States)

    Roberts, T. J.; Vignelles, D.; Liuzzo, M.; Giudice, G.; Aiuppa, A.; Coltelli, M.; Salerno, G.; Chartier, M.; Couté, B.; Berthet, G.; Lurton, T.; Dulac, F.; Renard, J.-B.

    2018-02-01

    Volcanoes are an important source of aerosols to the troposphere. Within minutes after emission, volcanic plume aerosol catalyses conversion of co-emitted HBr, HCl into highly reactive halogens (e.g. BrO, OClO) through chemical cycles that cause substantial ozone depletion in the dispersing downwind plume. This study quantifies the sub-to-supramicron primary volcanic aerosol emission (0.2-5 μm diameter) and its role in this process. An in-situ ground-based study at Mt Etna (Italy) during passive degassing co-deployed an optical particle counter and Multi-Gas SO2 sensors at high time resolution (0.1 Hz) enabling to characterise the aerosol number, size-distribution and emission flux. A tri-modal volcanic aerosol size distribution was found, to which lognormal distributions are fitted. Total particle volume correlates to SO2 (as a plume tracer). The measured particle volume:SO2 ratio equates to a sulfate:SO2 ratio of 1-2% at the observed meteorological conditions (40% Relative Humidity). A particle mass flux of 0.7 kg s-1 is calculated for the measured Mt Etna SO2 flux of 1950 tonnes/day. A numerical plume atmospheric chemistry model is used to simulate the role of the hygroscopic primary aerosol surface area and its humidity dependence on volcanic plume BrO and OClO chemistry. As well as predicting volcanic BrO formation and O3 depletion, the model achieves OClO/SO2 in broad quantitative agreement with recently reported Mt Etna observations, with a predicted maximum a few minutes downwind. In addition to humidity - that enhances aerosols surface area for halogen cycling - background ozone is predicted to be an important control on OClO/SO2. Dependence of BrO/SO2 on ambient humidity is rather low near-to-source but increases further downwind. The model plume chemistry also exhibits strong across-plume spatial variations between plume edge and centre.

  16. Cluster dynamics at different cluster size and incident laser wavelengths

    International Nuclear Information System (INIS)

    Desai, Tara; Bernardinello, Andrea

    2002-01-01

    X-ray emission spectra from aluminum clusters of diameter -0.4 μm and gold clusters of dia. ∼1.25 μm are experimentally studied by irradiating the cluster foil targets with 1.06 μm laser, 10 ns (FWHM) at an intensity ∼10 12 W/cm 2 . Aluminum clusters show a different spectra compared to bulk material whereas gold cluster evolve towards bulk gold. Experimental data are analyzed on the basis of cluster dimension, laser wavelength and pulse duration. PIC simulations are performed to study the behavior of clusters at higher intensity I≥10 17 W/cm 2 for different size of the clusters irradiated at different laser wavelengths. Results indicate the dependence of cluster dynamics on cluster size and incident laser wavelength

  17. Review of short wavelength lasers

    International Nuclear Information System (INIS)

    Hagelstein, P.L.

    1985-01-01

    There has recently been a substantial amount of research devoted to the development of short wavelength amplifiers and lasers. A number of experimental results have been published wherein the observation of significant gain has been claimed on transitions in the EUV and soft x-ray regimes. The present review is intended to discuss the main approaches to the creation of population inversions and laser media in the short wavelength regime, and hopefully aid workers in the field by helping to provide access to a growing literature. The approaches to pumping EUV and soft x-ray lasers are discussed according to inversion mechanism. The approaches may be divided into roughly seven categories, including collisional excitation pumping, recombination pumping, direct photoionization and photoexcitation pumping, metastable state storage plus optical pumping, charge exchange pumping, and finally, the extension of free electron laser techniques into the EUV and soft x-ray regimes. 250 references

  18. Review of short wavelength lasers

    Energy Technology Data Exchange (ETDEWEB)

    Hagelstein, P.L.

    1985-03-18

    There has recently been a substantial amount of research devoted to the development of short wavelength amplifiers and lasers. A number of experimental results have been published wherein the observation of significant gain has been claimed on transitions in the EUV and soft x-ray regimes. The present review is intended to discuss the main approaches to the creation of population inversions and laser media in the short wavelength regime, and hopefully aid workers in the field by helping to provide access to a growing literature. The approaches to pumping EUV and soft x-ray lasers are discussed according to inversion mechanism. The approaches may be divided into roughly seven categories, including collisional excitation pumping, recombination pumping, direct photoionization and photoexcitation pumping, metastable state storage plus optical pumping, charge exchange pumping, and finally, the extension of free electron laser techniques into the EUV and soft x-ray regimes. 250 references.

  19. Primary marine aerosol emissions from the Mediterranean Sea during pre-bloom and oligotrophic conditions: correlations to seawater chlorophyll a from a mesocosm study

    Science.gov (United States)

    Schwier, A. N.; Rose, C.; Asmi, E.; Ebling, A. M.; Landing, W. M.; Marro, S.; Pedrotti, M.-L.; Sallon, A.; Iuculano, F.; Agusti, S.; Tsiola, A.; Pitta, P.; Louis, J.; Guieu, C.; Gazeau, F.; Sellegri, K.

    2015-07-01

    The effect of ocean acidification and changing water conditions on primary (and secondary) marine aerosol emissions is not well understood on a regional or a global scale. To investigate this effect as well as the indirect effect on aerosol that changing biogeochemical parameters can have, ~ 52 m3 pelagic mesocosms were deployed for several weeks in the Mediterranean Sea during both winter pre-bloom and summer oligotrophic conditions and were subjected to various levels of CO2 to simulate the conditions foreseen in this region for the coming decades. After seawater sampling, primary bubble-bursting aerosol experiments were performed using a plunging water jet system to test both chemical and physical aerosol parameters (10-400 nm). Comparing results obtained during pre-bloom and oligotrophic conditions, we find the same four log-normal modal diameters (18.5 ± 0.6, 37.5 ± 1.4, 91.5 ± 2.0, 260 ± 3.2 nm) describing the aerosol size distribution during both campaigns, yet pre-bloom conditions significantly increased the number fraction of the second (Aitken) mode, with an amplitude correlated to virus-like particles, heterotrophic prokaryotes, TEPs (transparent exopolymeric particles), chlorophyll a and other pigments. Organic fractions determined from kappa closure calculations for the diameter, Dp ~ 50 nm, were much larger during the pre-bloom period (64 %) than during the oligotrophic period (38 %), and the organic fraction decreased as the particle size increased. Combining data from both campaigns together, strong positive correlations were found between the organic fraction of the aerosol and chlorophyll a concentrations, heterotrophic and autotrophic bacteria abundance, and dissolved organic carbon (DOC) concentrations. As a consequence of the changes in the organic fraction and the size distributions between pre-bloom and oligotrophic periods, we find that the ratio of cloud condensation nuclei (CCN) to condensation nuclei (CN) slightly decreased during the

  20. Experimental investigation of the cascadability of a cross-gain modulation wavelength converter

    DEFF Research Database (Denmark)

    Zheng, Xueyan; Liu, Fenghai; Kloch, Allan

    2000-01-01

    by adding a fiber grating-based optical add-drop multiplexer after the semiconductor optical amplifier (SOA) to enhance the high-frequency response of the wavelength converter. However, the low-frequency degradation of the signal together with amplified spontaneous emission (ASE) noise and jitter......The cascading characteristics of a wavelength converter based on cross-gain modulation (XGM) are studied experimentally using a recirculating loop at 10 Gb/s. The maximum cascaded number of the wavelength converter converting the signal to the same wavelength is improved from five to eight...

  1. Dual-wavelength phase-shifting digital holography selectively extracting wavelength information from wavelength-multiplexed holograms.

    Science.gov (United States)

    Tahara, Tatsuki; Mori, Ryota; Kikunaga, Shuhei; Arai, Yasuhiko; Takaki, Yasuhiro

    2015-06-15

    Dual-wavelength phase-shifting digital holography that selectively extracts wavelength information from five wavelength-multiplexed holograms is presented. Specific phase shifts for respective wavelengths are introduced to remove the crosstalk components and extract only the object wave at the desired wavelength from the holograms. Object waves in multiple wavelengths are selectively extracted by utilizing 2π ambiguity and the subtraction procedures based on phase-shifting interferometry. Numerical results show the validity of the proposed technique. The proposed technique is also experimentally demonstrated.

  2. MULTI-WAVELENGTH AFTERGLOWS OF FAST RADIO BURSTS

    International Nuclear Information System (INIS)

    Yi, Shuang-Xi; Gao, He; Zhang, Bing

    2014-01-01

    The physical origin of fast radio bursts (FRBs) is unknown. Detecting electromagnetic counterparts to FRBs in other wavelengths is essential to measure their distances and to determine their physical origin. Assuming that at least some of them are of cosmological origin, we calculate their afterglow light curves in multiple wavelengths (X-rays, optical, and radio) by assuming a range of total kinetic energies and redshifts. We focus on forward shock emission, but also consider the possibility that some of the FRBs might have bright reverse shock emission. In general, FRB afterglows are too faint to be detected by current detectors. Only if an FRB has a very low radiative efficiency in radio (hence, a very large kinetic energy), and when it is close enough to observe can its afterglow be detected in the optical and radio bands. We discuss observational strategies for detecting these faint afterglows using future telescopes such as Large Synoptic Survey Telescope and Expanded Very Large Array

  3. Mechanism of wavelength conversion in polystyrene doped with benzoxanthene: emergence of a complex.

    Science.gov (United States)

    Nakamura, Hidehito; Shirakawa, Yoshiyuki; Kitamura, Hisashi; Sato, Nobuhiro; Shinji, Osamu; Saito, Katashi; Takahashi, Sentaro

    2013-01-01

    Fluorescent guest molecules doped in polymers have been used to convert ultraviolet light into visible light for applications ranging from optical fibres to filters for the cultivation of plants. The wavelength conversion process involves the absorption of light at short wavelengths followed by fluorescence emission at a longer wavelength. However, a precise understanding of the light conversion remains unclear. Here we show light responses for a purified polystyrene base substrates doped with fluorescent benzoxanthene in concentrations varied over four orders of magnitude. The shape of the excitation spectrum for fluorescence emission changes significantly with the concentration of the benzoxanthene, indicating formation of a base substrate/fluorescent molecule complex. Furthermore, the wavelength conversion light yield increases in three stages depending on the nature of the complex. These findings identify a mechanism that will have many applications in wavelength conversion materials.

  4. Spatial variability of greenhouse gases emissions (CO2, CH4, N2O) in a tropical hydroelectric reservoir flooding primary forest (Petit Saut Reservoir, French Guiana)

    Science.gov (United States)

    Cailleaud, Emilie; Guérin, Frédéric; Bouillon, Steven; Sarrazin, Max; Serça, Dominique

    2014-05-01

    At the Petit Saut Reservoir (PSR, French Guiana, South America), vertical profiles were performed at 5 stations in the open waters (OW) and 6 stations in two shallow flooded forest (FF) areas between April 2012 and September 2013. Measurements included physico-chemical parameters, ammonium, nitrate and dissolved greenhouse gas (CO2, CH4, N2O) concentrations, dissolved and particulate organic carbon (DOC, POC) and nitrogen (PN), δ13C-POC and δ15N-PN . The diffusive fluxes were calculated from surface concentrations. The aim of this study was to estimate the spatial variations of greenhouse gas emissions at a dentrical hydroelectric reservoir located in the tropics and flooding primary forest. Twenty years after impoundment, the water column of the PSR is permanently and tightly stratified thermally in the FF whereas in the OW, the thermal gradients are not as stable. The different hydrodynamical behaviours between the two different zones have significant consequences on the biogeochemistry: oxygen barely diffuses down to the hypolimnion in the FF whereas destratification occurs sporadically during the rainy season in the OW. Although we found the same range of POC in the FF and the OW (2.5-29 μmol L-1) and 20% more DOC at the bottom of OW than in the FF (229-878 μmol L-1), CO2 and CH4 concentrations were always significantly higher in the FF (CO2: 11-1412 μmol L-1, CH4: 0.001-1015 μmol L-1) than in the OW. On average, the CO2 concentrations were 30-40% higher in the FF than in the OW and the CH4 concentrations were three times higher in the FF than in the OW. The δ13C-POC and C:N values did not suggest substantial differences in the sources of OM between the FF and OW. At all stations, POC at the bottom has an isotopic signature slightly lighter than the terrestrial OM in the surrounding forest whereas the isotopic signature of surface POM would result from phytoplankton and methanotrophs. The vertical profiles of nitrogen compounds reveal that the main

  5. Atomic carbon emission from photodissociation of CO2. [planetary atmospheric chemistry

    Science.gov (United States)

    Wu, C. Y. R.; Phillips, E.; Lee, L. C.; Judge, D. L.

    1978-01-01

    Atomic carbon fluorescence, C I 1561, 1657, and 1931 A, has been observed from photodissociation of CO2, and the production cross sections have been measured. A line emission source provided the primary photons at wavelengths from threshold to 420 A. The present results suggest that the excited carbon atoms are produced by total dissociation of CO2 into three atoms. The cross sections for producing the O I 1304-A fluorescence through photodissociation of CO2 are found to be less than 0.01 Mb in the wavelength region from 420 to 835 A. The present data have implications with respect to photochemical processes in the atmospheres of Mars and Venus.

  6. Impact of primary and secondary air supply intensity in stove on emissions of size-segregated particulate matter and carbonaceous aerosols from apple tree wood burning

    Science.gov (United States)

    Sun, Jian; Shen, Zhenxing; Zhang, Leiming; Zhang, Qian; Lei, Yali; Cao, Junji; Huang, Yu; Liu, Suixin; Zheng, Chunli; Xu, Hongmei; Liu, Hongxia; Pan, Hua; Liu, Pingping; Zhang, Renjian

    2018-04-01

    In order to assess emission factors (EF) more accurately from household biomass burning, a series of laboratory-controlled apple tree wood burning tests were conducted to measure the EFs of size-segregated particulate matter (PM) and carbonaceous aerosols. The controlled burning experiments were conducted with designed primary air (PA) and secondary air (SA) supply intensity. An optimum value of 7 m3·h- 1 was found for SA, resulting the highest modified combustion efficiency (92.4 ± 2.5%) as well as the lowest EFs of PM2.5 (0.13 ± 0.01 g·MJ- 1), OC (0.04 ± 0.03 g·MJ- 1) and EC (0.03 ± 0.01 g·MJ- 1). SA values of 7 and 10 m3·h- 1 resulted the lowest EFs for all the different PM sizes. In a test with PA of 6 m3·h- 1 and SA of 7 m3·h- 1, very low EFs were observed for OC1 (8.2%), OC2 (11.2%) and especially OP (Pyrolyzed OC) (0%, not detected), indicating nearly complete combustion under this air supply condition. Besides SA, higher PA was proved to have positive effects on PM and carbonaceous fraction emission reduction. For example, with a fixed SA of 1.5 m3·h- 1, EFs of PM2.5 decreased from 0.64 to 0.27 g·MJ- 1 when PA increased from 6 to 15 m3·h- 1 (P < 0.05). Similar reductions were also observed in EFs of OC, EC and size segregated PM.

  7. Millimetre wavelength methanol masers survey towards massive star forming regions

    Science.gov (United States)

    Umemoto, T.; Mochizuki, N.; Shibata, K. M.; Roh, D.-G.; Chung, H.-S.

    2007-03-01

    We present the results of a mm wavelength methanol maser survey towards massive star forming regions. We have carried out Class II methanol maser observations at 86.6 GHz, 86.9 GHz and 107.0 GHz, simultaneously, using the Nobeyama 45 m telescope. We selected 108 6.7 GHz methanol maser sources with declinations above -25 degrees and fluxes above 20 Jy. The detection limit of maser observations was ~3 Jy. Of the 93 sources surveyed so far, we detected methanol emission in 25 sources (27%) and “maser” emission in nine sources (10%), of which thre “maser” sources are new detections. The detection rate for maser emission is about half that of a survey of the southern sky (Caswell et al. 2000). There is a correlation between the maser flux of 107 GHz and 6.7 GHz/12 GHz emission, but no correlation with the “thermal” (non maser) emission. From results of other molecular line observations, we found that the sources with methanol emission show higher gas temperatures and twice the detection rate of SiO emission. This may suggest that dust evaporation and destruction by shock are responsible for the high abundance of methanol molecules, one of the required physical conditions for maser emission.

  8. Primary pulmonary lymphoma-role of fluoro-deoxy-glucose positron emission tomography-computed tomography in the initial staging and evaluating response to treatment - case reports and review of literature

    International Nuclear Information System (INIS)

    Agarwal, Krishan Kant; Dhanapathi, Halanaik; Nazar, Aftab Hasan; Kumar, Rakesh

    2016-01-01

    Primary pulmonary lymphoma (PPL) is an uncommon entity of non-Hodgkin lymphoma, which accounts for <1% of all cases of lymphoma. We present two rare cases of PPL of diffuse large B-cell lymphoma, which underwent 18 fluorine fluoro-deoxy-glucose positron emission tomography-computed tomography for initial staging and response evaluation after chemotherapy

  9. Making Displaced Holograms At Two Wavelengths

    Science.gov (United States)

    Witherow, William K.; Ecker, Andreas

    1989-01-01

    Two-wavelength holographic system augmented with pair of prisms to introduce small separation between holograms formed simultaneously at two wavelengths on holographic plate. Principal use in study of flows. Gradients in index of refraction of fluid caused by variations in temperature, concentration, or both. Holography at one wavelength cannot be used to distinguish between two types of variations. Difference between spacings of fringes in photographs reconstructed from holograms taken simultaneously at two different wavelengths manipulated mathematically to determine type of variation.

  10. [Research on the temperature field detection method of hot forging based on long-wavelength infrared spectrum].

    Science.gov (United States)

    Zhang, Yu-Cun; Wei, Bin; Fu, Xian-Bin

    2014-02-01

    A temperature field detection method based on long-wavelength infrared spectrum for hot forging is proposed in the present paper. This method combines primary spectrum pyrometry and three-stage FP-cavity LCTF. By optimizing the solutions of three group nonlinear equations in the mathematical model of temperature detection, the errors are reduced, thus measuring results will be more objective and accurate. Then the system of three-stage FP-cavity LCTF was designed on the principle of crystal birefringence. The system realized rapid selection of any wavelength in a certain wavelength range. It makes the response of the temperature measuring system rapid and accurate. As a result, without the emissivity of hot forging, the method can acquire exact information of temperature field and effectively suppress the background light radiation around the hot forging and ambient light that impact the temperature detection accuracy. Finally, the results of MATLAB showed that the infrared spectroscopy through the three-stage FP-cavity LCTF could meet the requirements of design. And experiments verified the feasibility of temperature measuring method. Compared with traditional single-band thermal infrared imager, the accuracy of measuring result was improved.

  11. Dual-wavelength erbium-doped fiber laser with asymmetric fiber Bragg grating Fabry-Perot cavity

    Science.gov (United States)

    Chen, Cong; Xu, Zhi-wei; Wang, Meng; Chen, Hai-yan

    2014-11-01

    A novel dual-wavelength fiber laser with asymmetric fiber Bragg grating (FBG) Fabry-Perot (FP) cavity is proposed and experimentally demonstrated. A couple of uniform FBGs are used as the cavity mirrors, and the third FBG is used as intracavity wavelength selector by changing its operation temperature. Experimental results show that by adjusting the operation temperature of the intracavity wavelength selector, a tunable dual-wavelength laser emission can be achieved. The results demonstrate the new concept of dual-wavelength lasing with asymmetric FBG FP resonator and its technical feasibility.

  12. Theory and experiment studies of the 1,4-bis(4-methoxylstyryl)benzene as a wavelength shifter of liquid scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Zhanlong [School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, Mianyang 621010 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Zhu, Jiayi [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, Mianyang 621010 (China); Bi, Yutie, E-mail: biyutie@sina.com [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, Mianyang 621010 (China); Xu, Yewei [School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Zhang, Qianfeng [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, Mianyang 621010 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Zhang, Xing [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Li, Junjiang [Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Zhang, Lin, E-mail: zhlmy@sina.com [School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, Mianyang 621010 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)

    2017-03-15

    A novel wavelength shifter of the 1,4-bis(4-methoxylstyryl)benzene (bis-4-MOSB) was synthesized by employing the classical Horner-Wadsworth-Emmons reaction. Feasible analysis of the bis-4-MOSB as the wavelength shifter in a ternary liquid scintillator, in which p-xylene (PX) was as the solvent and 2,5-diphenyloxazole (PPO) was as the primary fluor, was carried out. The optimum prescription with 3.5 g/L PPO and 25 mg/L bis-4-MOSB was obtained with regard to the light yield. A series of characterization tests based on the optimal formulation were performed. Compared with the 1,4-bis(2-methylstyryl)benzene (bis-MSB), the maximum absorption peak at 356 nm and maximum emission peak at 421 nm in n-hexane with the red shift of 10 nm and 3 nm, respectively, were measured accordingly. The light yield characterized by using a relative measurement method achieved as high as 75.85% of the anthracene crystal. A brief density functional calculation was conducted to have an insight into the electronic structure characteristic of the bis-4-MOSB in the scintillation process. - Graphic abstract: In our work, 1,4-bis(4-methoxylstyryl)benzene (bis-4-MOSB), as a novel wavelength shifter of liquid scintillator, was designed and synthesized. A comparison including absorption spectra and electronic structure characteristic between bis-4-MOSB and bis-MSB were conducted. Its maximum emission peak lied at 421 nm in n-hexane was corresponded to the maximum response range wavelength of PMT for the bis-4-MOSB. Furthermore, compared with the bis-MSB, the wavelength shifter of bis-4-MOSB showed a better luminescence performance.

  13. Theory and experiment studies of the 1,4-bis(4-methoxylstyryl)benzene as a wavelength shifter of liquid scintillator

    International Nuclear Information System (INIS)

    Zheng, Zhanlong; Zhu, Jiayi; Bi, Yutie; Xu, Yewei; Zhang, Qianfeng; Zhang, Xing; Li, Junjiang; Zhang, Lin

    2017-01-01

    A novel wavelength shifter of the 1,4-bis(4-methoxylstyryl)benzene (bis-4-MOSB) was synthesized by employing the classical Horner-Wadsworth-Emmons reaction. Feasible analysis of the bis-4-MOSB as the wavelength shifter in a ternary liquid scintillator, in which p-xylene (PX) was as the solvent and 2,5-diphenyloxazole (PPO) was as the primary fluor, was carried out. The optimum prescription with 3.5 g/L PPO and 25 mg/L bis-4-MOSB was obtained with regard to the light yield. A series of characterization tests based on the optimal formulation were performed. Compared with the 1,4-bis(2-methylstyryl)benzene (bis-MSB), the maximum absorption peak at 356 nm and maximum emission peak at 421 nm in n-hexane with the red shift of 10 nm and 3 nm, respectively, were measured accordingly. The light yield characterized by using a relative measurement method achieved as high as 75.85% of the anthracene crystal. A brief density functional calculation was conducted to have an insight into the electronic structure characteristic of the bis-4-MOSB in the scintillation process. - Graphic abstract: In our work, 1,4-bis(4-methoxylstyryl)benzene (bis-4-MOSB), as a novel wavelength shifter of liquid scintillator, was designed and synthesized. A comparison including absorption spectra and electronic structure characteristic between bis-4-MOSB and bis-MSB were conducted. Its maximum emission peak lied at 421 nm in n-hexane was corresponded to the maximum response range wavelength of PMT for the bis-4-MOSB. Furthermore, compared with the bis-MSB, the wavelength shifter of bis-4-MOSB showed a better luminescence performance.

  14. Effects of morphology and wavelength on the measurement accuracy of soot volume fraction by laser extinction

    Science.gov (United States)

    Wang, Ya-fei; Huang, Qun-xing; Wang, Fei; Chi, Yong; Yan, Jian-hua

    2018-01-01

    A novel method to evaluate the quantitative effects of soot morphology and incident wavelength on the measurement accuracy of soot volume fraction, by the laser extinction (LE) technique is proposed in this paper. The results indicate that the traditional LE technique would overestimate soot volume fraction if the effects of morphology and wavelength are not considered. Before the agglomeration of isolated soot primary particles, the overestimation of the LE technique is in the range of 2-20%, and rises with increasing primary particle diameter and with decreasing incident wavelength. When isolated primary particles are agglomerated into fractal soot aggregates, the overestimation would exceed 30%, and rise with increasing primary particle number per soot aggregate, fractal dimension and fractal prefactor and with decreasing incident wavelength to a maximum value of 55%. Finally, based on these results above, the existing formula of the LE technique gets modified, and the modification factor is 0.65-0.77.

  15. Bright Single InAsP Quantum Dots at Telecom Wavelengths in Position-Controlled InP Nanowires: The Role of the Photonic Waveguide.

    Science.gov (United States)

    Haffouz, Sofiane; Zeuner, Katharina D; Dalacu, Dan; Poole, Philip J; Lapointe, Jean; Poitras, Daniel; Mnaymneh, Khaled; Wu, Xiaohua; Couillard, Martin; Korkusinski, Marek; Schöll, Eva; Jöns, Klaus D; Zwiller, Valery; Williams, Robin L

    2018-05-09

    We report on the site-selected growth of bright single InAsP quantum dots embedded within InP photonic nanowire waveguides emitting at telecom wavelengths. We demonstrate a dramatic dependence of the emission rate on both the emission wavelength and the nanowire diameter. With an appropriately designed waveguide, tailored to the emission wavelength of the dot, an increase in the count rate by nearly 2 orders of magnitude (0.4 to 35 kcps) is obtained for quantum dots emitting in the telecom O-band, showing high single-photon purity with multiphoton emission probabilities down to 2%. Using emission-wavelength-optimized waveguides, we demonstrate bright, narrow-line-width emission from single InAsP quantum dots with an unprecedented tuning range of 880 to 1550 nm. These results pave the way toward efficient single-photon sources at telecom wavelengths using deterministically grown InAsP/InP nanowire quantum dots.

  16. Wavelength modulation spectroscopy of semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kohn, S.E.

    1977-10-01

    The use of modulation spectroscopy to study the electronic properties of solids has been very productive. The construction of a wide range Wavelength Modulation Spectrometer to study the optical properties of solids is described in detail. Extensions of the working range of the spectrometer into the vacuum ultraviolet are discussed. Measurements of the reflectivity and derivative reflectivity spectra of the lead chalcogenides, the chalcopyrite ZnGeP/sub 2/, the layer compounds GaSe and GaS and their alloys, the ferroelectric SbSI, layer compounds SnS/sub 2/ and SnSe/sub 2/, and HfS/sub 2/ were made. The results of these measurements are presented along with their interpretation in terms of band structure calculations.

  17. CO ICE PHOTODESORPTION: A WAVELENGTH-DEPENDENT STUDY

    International Nuclear Information System (INIS)

    Fayolle, Edith C.; Linnartz, Harold; Bertin, Mathieu; Romanzin, Claire; Michaut, Xavier; Fillion, Jean-Hugues; Oeberg, Karin I.

    2011-01-01

    UV-induced photodesorption of ice is a non-thermal evaporation process that can explain the presence of cold molecular gas in a range of interstellar regions. Information on the average UV photodesorption yield of astrophysically important ices exists for broadband UV lamp experiments. UV fields around low-mass pre-main-sequence stars, around shocks and in many other astrophysical environments are however often dominated by discrete atomic and molecular emission lines. It is therefore crucial to consider the wavelength dependence of photodesorption yields and mechanisms. In this work, for the first time, the wavelength-dependent photodesorption of pure CO ice is explored between 90 and 170 nm. The experiments are performed under ultra high vacuum conditions using tunable synchrotron radiation. Ice photodesorption is simultaneously probed by infrared absorption spectroscopy in reflection mode of the ice and by quadrupole mass spectrometry of the gas phase. The experimental results for CO reveal a strong wavelength dependence directly linked to the vibronic transition strengths of CO ice, implying that photodesorption is induced by electronic transition (DIET). The observed dependence on the ice absorption spectra implies relatively low photodesorption yields at 121.6 nm (Lyα), where CO barely absorbs, compared to the high yields found at wavelengths coinciding with transitions into the first electronic state of CO (A 1 Π at 150 nm); the CO photodesorption rates depend strongly on the UV profiles encountered in different star formation environments.

  18. Primary (recurrent) and metastatic lesions detection in cervical cancer: A comparison of positron emission tomography, CT and/or MRI image and pathological study

    International Nuclear Information System (INIS)

    Yen, T.C.; Tzen, K.Y.; Ma, S.Y.; Ng, K.K.; Hsueh, S.; Lai, C.H.

    2002-01-01

    Aim: This prospective study is to compare the results of primary (recurrence) and metastatic lesions detection, based on pathologic results, with computed tomography (CT) and/or magnetic resonance imaging (MRI) and positron emission tomography (PET) with [18F]-fluoro-2-deoxy-D-glucose (FDG) in invasive cervical cancer (ICC). Materials and Methods: An FDG PET scan was performed in 136 patients with ICC (107 squamous cell carcinoma [SCC], 18 adenocarcinoma [AdenoCa], 5 adeosquamous cell carcinoma, 4 small cell carcinoma, and 2 poorly differentiated carcinoma; from FIGO staging IB to IVB prior to operation). CT and/or MRI image were performed within one week before or after FDG PET scan was done. The accuracy of lymph node status was based on histological result or a second FDG PET combined with a CT and/or MRI image images. Results: Totally, 68 main tumor and 147 metastatic lesions were recognized by either histopathology or a follow up study. On a lesion basis, CT and/or MRI image images demonstrated 63 (92.6 %) main tumor and 103 (70.1 %) metastatic lesions. For lymph node metastatic lesions detection, there were 6(75 %) enlarged inguinal lymph nodes, 38(76 %) enlarged pelvic lymph nodes (PLN), 28(73.7 %) enlarged para-aortic lymph nodes (PAN), 8(50 %) enlarged supraclavicular lymph nodes (SLNs), and 5(62.5 %) enlarged mediastinal lymph nodes (MLNs). Liver metastases were found in 4(100 %), in lung in 7(70 %) and in bone in 5(83.3 %). Peritoneal metastases were found in 2(28.6 %). FDG PET demonstrated 63 (92.6 %) and 135 (91.8 %) metastatic lesions. For lymph node metastases, FDG PET found 8(100 %) enlarged inguinal lymph nodes, 44(88 %) enlarged PLNs, 36(94.7 %) enlarged PANs, 15(93.8 %) enlarged SLNs, and 8(100 %) enlarged MLNs. Liver metastases were found in 4(100 %), in lung in 9(90 %) and in bone in 6(100 %). Peritoneal metastases were found in 5(71.4 %). On a patient basis, with FDG PET scan, 31(22.8%) were upstaging while 4(2.9%) were down staging. 35

  19. Positron Emission Tomography/Computed Tomography Assessment After Immunochemotherapy and Irradiation Using the Lugano Classification Criteria in the IELSG-26 Study of Primary Mediastinal B-Cell Lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Ceriani, Luca, E-mail: luca.ceriani@eoc.ch [Nuclear Medicine and PET-CT Center, Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); Martelli, Maurizio [Department of Cellular Biotechnologies and Hematology, Sapienza University, Rome (Italy); Gospodarowicz, Maria K. [Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Ricardi, Umberto [Department of Oncology, University of Torino, Torino (Italy); Ferreri, Andrés J.M. [Unit of Lymphoid Malignancies, Department of Onco-Hematology, Istituto Di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Milano (Italy); Chiappella, Annalisa [Hematology, Azienda Ospedaliera Universitaria Città della Salute e della Scienza, Torino (Italy); Stelitano, Caterina [Hematology, Azienda Ospedaliera Bianchi-Melacrino-Morelli, Reggio Calabria (Italy); Balzarotti, Monica [Hematology, IRCCS Humanitas Cancer Center, Rozzano, Milan (Italy); Cabrera, Maria E. [Hematology, Hospital del Salvador, Universidad de Chile, Santiago (Chile); Cunningham, David [Department of Medicine, The Royal Marsden National Health Service Foundation Trust, London and Surrey (United Kingdom); Guarini, Attilio [Hematology Unit, Istituto Nazionale Tumori Giovanni Paolo II IRCCS, Bari (Italy); Zinzani, Pier Luigi [Institute of Hematology and Medical Oncology, Policlinico S.Orsola-Malpighi, Bologna (Italy); Giovanella, Luca [Nuclear Medicine and PET-CT Center, Oncology Institute of Southern Switzerland, Bellinzona (Switzerland); Johnson, Peter W.M. [Cancer Research UK Centre, University of Southampton, Southampton (United Kingdom); Zucca, Emanuele [Oncology Department, Oncology Institute of Southern Switzerland, Bellinzona (Switzerland)

    2017-01-01

    Purpose: To assess the predictive value of {sup 18}F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) for disease recurrence after immunochemotherapy (R-CHT) and mediastinal irradiation (RT), using the recently published criteria of the Lugano classification to predict outcomes for patients with primary mediastinal large B-cell lymphoma. Methods and Materials: Among 125 patients prospectively enrolled in the IELSG-26 study, 88 were eligible for central review of PET/CT scans after completion of RT. Responses were evaluated using the 5-point Deauville scale at the end of induction R-CHT and after consolidation RT. According to the Lugano classification, a complete metabolic response (CMR) was defined by a Deauville score (DS) ≤3. Results: The CMR (DS1, -2, or -3) rate increased from 74% (65 patients) after R-CHT to 89% (78 patients) after consolidation RT. Among the 10 patients (11%) with persistently positive scans, the residual uptake after RT was slightly higher than the liver uptake in 6 patients (DS4; 7%) and markedly higher in 4 patients (DS5; 4%): these patients had a significantly poorer 5-year progression-free survival and overall survival. At a median follow-up of 60 months (range, 35-107 months), no patients with a CMR after RT have relapsed. Among the 10 patients who did not reach a CMR, 3 of the 4 patients (positive predictive value, 75%) with DS5 after RT had subsequent disease progression (within the RT volume in all cases) and died. All patients with DS4 had good outcomes without recurrence. Conclusions: All the patients obtaining a CMR defined as DS ≤3 remained progression-free at 5 years, confirming the excellent negative predictive value of the Lugano classification criteria in primary mediastinal large B-cell lymphoma patients. The few patients with DS4 also had an excellent outcome, suggesting that they do not necessarily require additional therapy, because the residual {sup 18}F-fluorodeoxyglucose uptake may

  20. VIGOR DE SEMENTES DE MILHO (Zea mays L. AVALIADO PELA PRECOCIDADE DE EMISSÃO DA RAIZ PRIMÁRIA EVALUATION OF CORN (Zea mays L. SEED VIGOR THROUGH THE PRECOCITY OF PRIMARY ROOT EMISSION

    Directory of Open Access Journals (Sweden)

    Francisco Ferraz de Toledo

    1999-01-01

    Full Text Available Foi desenvolvido trabalho baseado na determinação da precocidade da emissão da raiz primária de sementes de milho, em dez lotes de um mesmo cultivar. Este processo constou da distribuição de 200 sementes de cada lote sobre folhas de papel umedecido e, também, rolos de papel, que permaneceram em germinador a 25 °C; de 12 em 12 horas, aquelas que apresentaram emissão da raiz primária foram removidas, contadas e anotadas. Para estabelecer comparação entre os métodos e os lotes, paralelamente, as sementes eram avaliadas através da determinação do grau de umidade, dos testes de germinação e de vigor (primeira contagem, teste de frio com solo e emergência de plântulas em campo. Concluiu-se que há possibilidade de se utilizar o teste de emissão da raiz primária, em rolos de papel, para a avaliação do vigor de sementes de milho.The objectives of this study were to evaluate the variability of the emission of seed radicle of corn (Zea mays L. and to establish indexes of primary root emission to test the vigor of commercial seed lots. Samples of corn seeds not treated with fungicides, were taken from ten lots of the same cultivar. Two hundred seeds from each lot were distributed on wetted paper towels and also within paper rolles at 25 °C. Each 12 hours, seeds with primary root emission were counted and removed. Indexes of primary root emission were calculated and compared to conventional laboratory tests (first count; accelerated aging; cold test and field emergence. It was concluded that the primary root emission test, in rolled paper towels can be of great value for evaluating the vigor of corn seeds.

  1. Single-Institution Experience in the Treatment of Primary Mediastinal B Cell Lymphoma Treated With Immunochemotherapy in the Setting of Response Assessment by 18Fluorodeoxyglucose Positron Emission Tomography

    International Nuclear Information System (INIS)

    Pinnix, Chelsea C.; Dabaja, Bouthaina; Ahmed, Mohamed Amin; Chuang, Hubert H.; Costelloe, Colleen; Wogan, Christine F.; Reed, Valerie; Romaguera, Jorge E.; Neelapu, Sattva; Oki, Yasuhiro; Rodriguez, M. Alma; Fayad, Luis; Hagemeister, Frederick B.; Nastoupil, Loretta; Turturro, Francesco; Fowler, Nathan; Fanale, Michelle A.; Nieto, Yago; Khouri, Issa F.; Ahmed, Sairah

    2015-01-01

    Purpose: Excellent outcomes obtained after infusional dose-adjusted etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, and rituximab (R-EPOCH) alone have led some to question the role of consolidative radiation therapy (RT) in the treatment of primary mediastinal B cell lymphoma (PMBL). We reviewed the outcomes in patients treated with 1 of 3 rituximab-containing regimens (cyclophosphamide, doxorubicin, vincristine, prednisone [R-CHOP]; hyperfractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone [R-HCVAD], or R-EPOCH) with or without RT. We also evaluated the ability of positron emission tomography–computed tomography (PET-CT) to identify patients at risk of relapse. Methods and Materials: We retrospectively identified 97 patients with diagnoses of stage I/II PMBCL treated at our institution between 2001 and 2013. The clinical characteristics, treatment outcomes, and toxicity were assessed. We analyzed whether postchemotherapy PET-CT could identify patients at risk for progressive disease according to a 5 point scale (5PS) Deauville score assigned. Results: Among 97 patients (median follow-up time, 57 months), the 5-year overall survival rate was 99%. Of patients treated with R-CHOP, 99% received RT; R-HCVAD, 82%; and R-EPOCH, 36%. Of 68 patients with evaluable end-of-chemotherapy PET-CT scans, 62% had a positive scan (avidity above that of the mediastinal blood pool [Deauville 5PS = 3]), but only 9 patients experienced relapse (n=1) or progressive disease (n=8), all with a 5PS of 4 to 5. Of the 25 patients who received R-EPOCH, 4 experienced progression, all with 5PS of 4 to 5; salvage therapy (RT and autologous stem cell transplantation) was successful in all cases. Conclusion: Combined modality immunochemotherapy and RT is well tolerated and effective for treatment of PMBCL. A postchemotherapy 5PS of 4 to 5, rather than 3 to 5, can identify patients at high risk of progression who should be considered for therapy beyond

  2. Value of (18F)-FDG positron emission tomography, computed tomography, and magnetic resonance imaging in diagnosing primary and recurrent ovarian carcinoma

    International Nuclear Information System (INIS)

    Kubik-Huch, R.A.; Doerffler, W.; Marincek, B.; Schulthess, G.K.; Steinert, H.C.; Koechli, O.R.; Haller, U.; Seifert, B.

    2000-01-01

    The aim of this study was to compare prospectively the accuracy of whole-body positron emission tomography (PET), CT and MRI in diagnosing primary and recurrent ovarian cancer. Nineteen patients (age range 23-76 years) were recruited with suspicious ovarian lesions at presentation (n = 8) or follow-up for recurrence (n = 11). All patients were scheduled for laparotomy and histological confirmation. Whole-body PET with FDG, contrast-enhanced spiral CT of the abdomen, including the pelvis, and MRI of the entire abdomen were performed. Each imaging study was evaluated separately. Imaging findings were correlated with histopathological diagnosis. The sensitivity, specificity and accuracy for lesion characterization in patients with suspicious ovarian lesions (n = 7) were, respectively: 100, 67 and 86 % for PET; 100, 67 and 86 % for CT; and 100, 100 and 100 % for MRI. For the diagnosis of recurrent disease (n = 10), PET had a sensitivity of 100 %, specificity of 50 % and accuracy of 90 %. The PET technique was the only technique which correctly identified a single transverse colon metastasis. Results for CT were 40, 50 and 43 %, and for MRI 86, 100 and 89 %, respectively. No statistically significant difference was seen. Neither FDG PET nor CT nor MRI can replace surgery in the detection of microscopic peritoneal disease. No statistically significant difference was observed for the investigated imaging modalities with regard to lesion characterization or detection of recurrent disease; thus, the methods are permissible alternatives. The PET technique, however, has the drawback of less accurate spatial assignment of small lesions compared with CT and MRI. (orig.)

  3. Short wavelength limits of current shot noise suppression

    International Nuclear Information System (INIS)

    Nause, Ariel; Dyunin, Egor; Gover, Avraham

    2014-01-01

    Shot noise in electron beam was assumed to be one of the features beyond control of accelerator physics. Current results attained in experiments at Accelerator Test Facility in Brookhaven and Linac Coherent Light Source in Stanford suggest that the control of the shot noise in electron beam (and therefore of spontaneous radiation and Self Amplified Spontaneous Emission of Free Electron Lasers) is feasible at least in the visible range of the spectrum. Here, we present a general linear formulation for collective micro-dynamics of e-beam noise and its control. Specifically, we compare two schemes for current noise suppression: a quarter plasma wavelength drift section and a combined drift/dispersive (transverse magnetic field) section. We examine and compare their limits of applicability at short wavelengths via considerations of electron phase-spread and the related Landau damping effect

  4. Short wavelength limits of current shot noise suppression

    Energy Technology Data Exchange (ETDEWEB)

    Nause, Ariel, E-mail: arielnau@post.tau.ac.il [Faculty of Exact Sciences, Department of Physics, Tel Aviv University, Tel Aviv (Israel); Dyunin, Egor; Gover, Avraham [Faculty of Engineering, Department of Physical Electronics, Tel Aviv University, Tel Aviv (Israel)

    2014-08-15

    Shot noise in electron beam was assumed to be one of the features beyond control of accelerator physics. Current results attained in experiments at Accelerator Test Facility in Brookhaven and Linac Coherent Light Source in Stanford suggest that the control of the shot noise in electron beam (and therefore of spontaneous radiation and Self Amplified Spontaneous Emission of Free Electron Lasers) is feasible at least in the visible range of the spectrum. Here, we present a general linear formulation for collective micro-dynamics of e-beam noise and its control. Specifically, we compare two schemes for current noise suppression: a quarter plasma wavelength drift section and a combined drift/dispersive (transverse magnetic field) section. We examine and compare their limits of applicability at short wavelengths via considerations of electron phase-spread and the related Landau damping effect.

  5. Reliable Operation for 14500 h of a Wavelength-Stabilized Diode Laser System on a Microoptical Bench at 671 nm

    DEFF Research Database (Denmark)

    Sumpf, Bernd; Maiwald, Martin; Müller, André

    2012-01-01

    Reliability tests for wavelength-stabilized compact diode laser systems emitting at 671 nm are presented. The devices were mounted on microoptical benches with the dimensions of 13 mm $\\times\\,$4 mm. Reflecting Bragg gratings were used for wavelength stabilization and emission width narrowing...

  6. Effective wavelength calibration for moire fringe projection

    International Nuclear Information System (INIS)

    Purcell, Daryl; Davies, Angela; Farahi, Faramarz

    2006-01-01

    The fringe patterns seen when using moire instruments are similar to the patterns seen in traditional interferometry but differ in the spacing between consecutive fringes. In traditional interferometry, the spacing is constant and related to the wavelength of the source. In moire fringe projection, the spacing (the effective wavelength) may not be constant over the field of view and the spacing depends on the system geometry. In these cases, using a constant effective wavelength over the field of view causes inaccurate surface height measurements. We examine the calibration process of the moirefringe projection measurement, which takes this varying wavelength into account to produce a pixel-by-pixel wavelength map. The wavelength calibration procedure is to move the object in the out-of-plane direction a known distance until every pixel intensity value goes through at least one cycle. A sinusoidal function is then fit to the data to extract the effective wavelength pixel by pixel, yielding an effective wavelength map. A calibrated step height was used to validate the effective wavelength map with results within 1% of the nominal value of the step height. The error sources that contributed to the uncertainty in determining the height of the artifact are also investigated

  7. A proposed new method for the determination of the solar irradiance at EUV wavelength range

    Science.gov (United States)

    Feldman, Uri; Doschek, G. A.; Seely, J. F.; Landi, E.; Dammasch, I.

    The solar irradiance in the far ultraviolet (FUV) and extreme ultraviolet (EUV) and its time variability are important inputs to geospace models. It provides the primary mechanism for heating the earth's upper atmosphere and creating the ionosphere. Understanding various space weather phenomena requires reliable detailed knowledge of the solar EUV irradiance. Ideally one would like to have a single well-calibrated, high-resolution spectrometer that can continuously monitor the solar irradiance over the relevant wavelengths range. Since this is much too difficult to accomplish, a number of monitoring instruments were constructed in the past, each covering a fraction of the required wavelength range. Assembling solar irradiance from measurements by a number of instruments is extremely difficult and is usually plagued by large uncertainties. To overcome some of the difficulties resulting from such procedures, empirical models have been developed that rely in large part on solar activity levels as proxies. In recent years a different approach has been established for the determination of the solar irradiance, an approach independent of irradiance observations. The new approach is based on the line intensities calculated from emission measure (EM) distributions across the solar surface. The EM distributions are derived from spatially and spectrally resolved measurements of line intensities and describe the temperature and density structure of the basic large scale features of the solar atmosphere, specifically coronal holes, quiet Sun, and active regions. Recently, as a result of detailed analysis of solar upper atmosphere (SUA) spectra recorded by SUMER/SoHO it was discovered that, in contrast to earlier beliefs, the solar EM in 3x105 -4x106 K plasmas does not appear to vary continuously with temperature as previously assumed. Instead it appears to be composed of isothermal structures where each can attain but one of the following four main temperatures: 5x105 , 9x105

  8. Use of primary beam filtration in estimating mass attenuation coefficients by Compton scattering

    International Nuclear Information System (INIS)

    O'Connor, B.H.; Chang, W.J.

    1985-01-01

    Mass attenuation coefficients (MACs) are frequently estimated over a range of wavelengths in x-ray spectrometry from the intensity of the Compton peak I /SUB C/ associated with a prominent tube line. The MAC μ /SUB ll/ at wavelength lambda is estimated from the MAC at the Compton wavelength lambda /SUB C/ with the approximations μ /SUB ll/ α μ /SUB C/ and μ /SUB C/ α l/I /SUB C/ , Systematic errors may introduce absorption edge bias (AEB) effects into the results, caused by sample components with absorption edges between lambda /SUB C/ and lambda. A procedure is described which eliminates AEB effects by measuring I /SUB C/ using emission radiation from a primary beam filter

  9. The fabrication of millimeter-wavelength accelerating structures

    International Nuclear Information System (INIS)

    Chou, P.J.; Bowden, G.B.; Copeland, M.R.

    1996-11-01

    There is a growing interest in the development of high gradient (≥ 1 GeV/m) accelerating structures. The need for high gradient acceleration based on current microwave technology requires the structures to be operated in the millimeter wavelength. Fabrication of accelerating structures at millimeter scale with sub-micron tolerances poses great challenges. The accelerating structures impose strict requirements on surface smoothness and finish to suppress field emission and multipactor effects. Various fabrication techniques based on conventional machining and micromachining have been evaluated and tested. These will be discussed and measurement results presented

  10. An improved wavelength selection scheme for Monte Carlo solvers applied to hypersonic plasmas

    International Nuclear Information System (INIS)

    Feldick, Andrew; Modest, Michael F.

    2011-01-01

    A new databasing scheme is developed for Monte Carlo Ray Tracing methods applied to hypersonic planetary entry. In this scheme, the complex relationships for the emission wavelength selection of atomic and molecular species in nonequilibrium flows are simplified by developing random number relationships for individual transitions, as opposed to using relationships for the spectral emission coefficient of a given species. These new techniques speed up wavelength selection by about 2 orders of magnitude, and offer flexibility for use in weighted or part-spectrum Monte Carlo solvers.

  11. Differentiating primary CNS lymphoma from glioblastoma multiforme: assessment using arterial spin labeling, diffusion-weighted imaging, and {sup 18}F-fluorodeoxyglucose positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, Koji; Yoshiura, Takashi; Hiwatashi, Akio; Togao, Osamu; Abe, Koichiro; Kikuchi, Kazufumi; Maruoka, Yasuhiro; Honda, Hiroshi [Kyushu University, Department of Clinical Radiology, Graduate School of Medical Sciences, Fukuoka (Japan); Yoshimoto, Koji; Mizoguchi, Masahiro [Kyushu University, Department of Neurosurgery, Graduate School of Medical Sciences, Fukuoka (Japan); Suzuki, Satoshi O.; Iwaki, Toru [Kyushu University, Department of Neuropathology, Graduate School of Medical Sciences, Fukuoka (Japan)

    2013-02-15

    Our purpose was to evaluate the diagnostic performance of arterial spin labeling (ASL) perfusion imaging, diffusion-weighted imaging (DWI), and {sup 18}F-fluorodeoxyglucose positron emission tomography (FDG-PET) in differentiating primary central nervous system lymphomas (PCNSLs) from glioblastoma multiformes (GBMs). Fifty-six patients including 19 with PCNSL and 37 with GBM were retrospectively studied. From the ASL data, an absolute tumor blood flow (aTBF) and a relative tumor blood flow (rTBF) were obtained within the enhancing portion of each tumor. In addition, the minimum apparent diffusion coefficient (ADCmin) and the maximum standard uptake value (SUVmax) were obtained from DWI and FDG-PET data, respectively. Each of the four parameters was compared between PCNSLs and GBMs using Kruskal-Wallis test. The performance in discriminating between PCNSLs and GBMs was evaluated using the receiver-operating characteristics analysis. Area-under-the-curve (AUC) values were compared among the four parameters using a nonparametric method. The aTBF, rTBF, and ADCmin were significantly higher in GBMs (mean aTBF {+-} SD = 91.6 {+-} 56.0 mL/100 g/min, mean rTBF {+-} SD = 2.61 {+-} 1.61, mean ADCmin {+-} SD = 0.78 {+-} 0.19 x 10{sup -3} mm{sup 2}/s) than in PCNSLs (mean aTBF {+-} SD = 37.3 {+-} 10.5 mL/100 g/min, mean rTBF {+-} SD = 1.24 {+-} 0.37, mean ADCmin {+-} SD = 0.61 {+-} 0.13 x 10{sup -3} mm{sup 2}/s) (p < 0.005, respectively). In addition, SUVmax was significantly lower in GBMs (mean {+-} SD = 13.1 {+-} 6.34) than in PCNSLs (mean {+-} SD = 22.5 {+-} 7.83) (p < 0.005). The AUC for aTBF (0.888) was higher than those for rTBF (0.810), ADCmin (0.768), and SUVmax (0.848), although their difference was not statistically significant. ASL perfusion imaging is useful for differentiating PCNSLs from GBMs as well as DWI and FDG-PET. (orig.)

  12. Is 18F-fluorocholine-positron emission tomography/computerized tomography a new imaging tool for detecting hyperfunctioning parathyroid glands in primary or secondary hyperparathyroidism?

    Science.gov (United States)

    Michaud, Laure; Burgess, Alice; Huchet, Virginie; Lefèvre, Marine; Tassart, Marc; Ohnona, Jessica; Kerrou, Khaldoun; Balogova, Sona; Talbot, Jean-Noël; Périé, Sophie

    2014-12-01

    Preoperative ultrasonography and scintigraphy using (99m)Tc-sestamibi are commonly used to localize abnormal parathyroid glands. In cases of discrepant results between scintigraphy and ultrasonography, it is important to rely on another diagnostic imaging modality. (18)F-fluorodeoxyglucose (FDG) and (11)C-methionine positron emission tomography (PET) have been studied, but are imperfect to detect abnormal parathyroid glands. Recently, first cases of abnormal parathyroid glands taking-up radiolabelled choline were discovered incidentally in men referred to (11)C-choline or (18)F-fluorocholine (FCH)-PET/CT for prostate cancer. We checked if FCH uptake was a general feature of adenomatous or hyperplastic parathyroid glands. FCH-PET/CT was performed in 12 patients with primary (n = 8) or secondary hyperparathyroidism (1 dialyzed, 3 grafted) and with discordant or equivocal results on preoperative ultrasonography (US) and/or (123)I/(99m)Tc-sestamibi dual-phase scintigraphy. The results of the FCH-PET/CT were evaluated, with surgical exploration and histopathologic examination as the standard of truth. On a per-patient level, the detection rate of FCH-PET/CT (at least one FCH focus corresponding to an abnormal parathyroid gland in a given patient) was 11/12 = 92%. FCH-PET/CT detected 18 foci interpreted as parathyroid glands and correctly localized 17 abnormal parathyroid glands (7 adenomas and 10 hyperplasias). On a per-lesion level, FCH-PET/CT results were 17 TP, 2 false negative ie, a lesion-based sensitivity of 89%, and 1 false positive. As the main result of this pilot study, we show that in patients with hyperparathyroidism and with discordant or equivocal results on scintigraphy or on ultrasonography, adenomatous or hyperplastic parathyroid glands can be localized by FCH-PET/CT with good accuracy. Furthermore, FCH-PET/CT can solve discrepant results between preoperative ultrasonography and scintigraphy and has thus a potential as a functional imaging modality in

  13. Wavelength scaling of laser plasma coupling

    International Nuclear Information System (INIS)

    Kruer, W.L.

    1983-01-01

    The use of shorter wavelength laser light both enhances collisional absorption and reduces deleterious collective plasma effects. Coupling processes which can be important in reactor-size targets are briefly reviewed. Simple estimates are presented for the intensity-wavelength regime in which collisional absorption is high and collective effects are minimized

  14. Influence of ablation wavelength and time on optical properties of laser ablated carbon dots

    Science.gov (United States)

    Isnaeni, Hanna, M. Yusrul; Pambudi, A. A.; Murdaka, F. H.

    2017-01-01

    Carbon dots, which are unique and applicable materials, have been produced using many techniques. In this work, we have fabricated carbon dots made of coconut fiber using laser ablation technique. The purpose of this work is to evaluate two ablation parameters, which are ablation wavelength and ablation time. We used pulsed laser from Nd:YAG laser with emit wavelength at 355 nm, 532 nm and 1064 nm. We varied ablation time one hour and two hours. Photoluminescence and time-resolved photoluminescence setup were used to study the optical properties of fabricated carbon dots. In general, fabricated carbon dots emit bluish green color emission upon excitation by blue laser. We found that carbon dots fabricated using 1064 nm laser produced the highest carbon dots emission among other samples. The peak wavelength of carbon dots emission is between 495 nm until 505 nm, which gives bluish green color emission. Two hours fabricated carbon dots gave four times higher emission than one hour fabricated carbon dot. More emission intensity of carbon dots means more carbon dots nanoparticles were fabricated during laser ablation process. In addition, we also measured electron dynamics of carbon dots using time-resolved photoluminescence. We found that sample with higher emission has longer electron decay time. Our finding gives optimum condition of carbon dots fabrication from coconut fiber using laser ablation technique. Moreover, fabricated carbon dots are non-toxic nanoparticles that can be applied for health, bio-tagging and medical applications.

  15. A guidance manual for estimating greenhouse gas emissions from fuel combustion and process-related sources for primary base metals smelting and refining

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-03-01

    This technical guidance manual is a useful resource for helping the metals industry compile inventories of its greenhouse gas (GHG) emissions. The guidance is consistent with Canada's national GHG accounting methodologies. It provides information to smelters and refiners of base metals on how to estimate their GHG emissions from fuel combustion and specific process-related activities. The base metals group in this manual included copper, nickel, lead, zinc, and cobalt. Fuel combustion includes all stationary combustion activities for generating heat or work, and includes waste incineration if the waste heat is used for energy. It also includes mobile fuel combustion activities such as on-site transportation of raw materials from one process to another. Guidance is provided for carbon dioxide (CO{sub 2}), methane (CH{sub 4}) and nitrous oxide (N{sub 2}O). Process-related activities include specific industrial processes that contribute to GHG emissions. For base metal smelting, this includes CO{sub 2} emissions from use of carbonate reagents, use of reducing agents, electrode consumption, and hydrofluorocarbons (HFC) emissions from use in refrigeration systems. This document also included sections on quality assurance; aspects of uncertainty assessment; verification; and, reporting of emissions information. refs., tabs., figs.

  16. Research with high-power short-wavelength lasers

    International Nuclear Information System (INIS)

    Holzrichter, J.F.; Campbell, E.M.; Lindl, J.D.; Storm, E.

    1985-01-01

    Three important high-temperature, high-density experiments were conducted recently using the 10-TW, short-wavelength Novette laser system at the Lawrence Livermore National Laboratory. These experiments demonstrated successful solutions to problems that arose during previous experiments with long wavelength lasers (lambda greater than or equal to 1μm) in which inertial confinement fusion (ICF), x-ray laser, and other high-temperature physics concepts were being tested. The demonstrations were: (1) large-scale plasmas (typical dimensions of up to 1000 laser wavelengths) were produced in which potentially deleterious laser-plasma instabilities were collisionally damped. (2) Deuterium-tritium fuel was imploded to a density of 20 g/cm 3 and a pressure of 10 10 atm. (3) A 700-fold amplification of soft x rays by stimulated emission at 206 and 209 A (62 eV) from Se +24 ions was observed in a laser-generated plasma. Isoelectronic scaling to 155 A (87 eV) in Y +29 was also demonstrated

  17. Clinicopathological and prognostic relevance of uptake level using 18F-fluorodeoxyglucose positron emission tomography/computed tomography fusion imaging (18F-FDG PET/CT) in primary breast cancer

    International Nuclear Information System (INIS)

    Ueda, Shigeto; Tsuda, Hitoshi; Asakawa, Hideki

    2008-01-01

    Using integrated 18 F-fluorodeoxyglucose positron emission tomography/computed tomography fusion imaging ( 18 F-FDG PET/CT), the clinical significance of 18 F-FDG uptake was evaluated in patients with primary breast cancer. Clinicopathological correlation with the level of maximum standardized uptake values (SUV) 60 min obtained from preoperative 18 F-FDG PET/CT were examined in 152 patients with primary breast cancer. The prognostic impact of the level of SUV was explored using simulated prognosis derived from computed program Adjuvant! in 136 (89%) patients with invasive ductal carcinoma (IDC). High SUV level was significantly correlated with tumor invasive size (≤2 cm) (P 18 F-FDG would be predictive of poor prognosis in patients with primary breast cancer, and aggressive features of cancer cells in patients with early breast cancer. 18 F-FDG PET/CT could be a useful tool to pretherapeutically predict biological characteristics and baseline risk of breast cancer. (author)

  18. Secondary emission coefficient dependence on the angle of incidence of primary electrons on CsI and LiF layers. [0. 9 to 3 keV, mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Shabel' nikova, A E; Yasnopol' skii, N L

    1976-08-01

    The angular dependence was studied of the secondary emission coefficient sigma for CsI and LiF dielectrics which have large sigma in conditions of normal incidence of primary electrons. Measurements were taken down to the angle of 85 deg for energies of primary electrons between 0.9 and 3 keV. In the whole range of angles a nonmonotonic angular dependence sigma is observed. The dependence shows itself particularly clearly for CsI at large energies of primary electrons. Such a behaviour is due to the decrease in the depth of yield of inelastically reflected electrons and to the increase in the inelastic reflection coefficient of the substance.

  19. In Situ Measurement of Alkali Metals in an MSW Incinerator Using a Spontaneous Emission Spectrum

    Directory of Open Access Journals (Sweden)

    Weijie Yan

    2017-03-01

    Full Text Available This paper presents experimental investigations of the in situ diagnosis of the alkali metals in the municipal solid waste (MSW flame of an industrial grade incinerator using flame emission spectroscopy. The spectral radiation intensities of the MSW flame were obtained using a spectrometer. A linear polynomial fitting method is proposed to uncouple the continuous spectrum and the characteristic line. Based on spectra processing and a non-gray emissivity model, the flame temperature, emissivity, and intensities of the emission of alkali metals were calculated by means of measuring the spectral radiation intensities of the MSW flame. Experimental results indicate that the MSW flame contains alkali metals, including Na, K, and even Rb, and it demonstrates non-gray characteristics in a wavelength range from 500 nm to 900 nm. Peak intensities of the emission of the alkali metals were found to increase when the primary air was high, and the measured temperature varied in the same way as the primary air. The temperature and peak intensities of the lines of emission of the alkali metals may be used to adjust the primary airflow and to manage the feeding of the MSW to control the alkali metals in the MSW flame. It was found that the peak intensity of the K emission line had a linear relationship with the peak intensity of the Na emission line; this correlation may be attributed to their similar physicochemical characteristics in the MSW. The variation trend of the emissivity of the MSW flame and the oxygen content in the flue gas were almost opposite because the increased oxygen content suppressed soot formation and decreased soot emissivity. These results prove that the flame emission spectroscopy technique is feasible for monitoring combustion in the MSW incinerator in situ.

  20. First Resolved Images of the Mira AB Symbiotic Binary at Centimeter Wavelengths

    OpenAIRE

    Matthews, Lynn D.; Karovska, Margarita

    2005-01-01

    We report the first spatially resolved radio continuum measurements of the Mira AB symbiotic binary system, based on observations obtained with the Very Large Array (VLA). This is the first time that a symbiotic binary has been resolved unambiguously at centimeter wavelengths. We describe the results of VLA monitoring of both stars over a ten month period, together with constraints on their individual spectral energy distributions, variability, and radio emission mechanisms. The emission from...

  1. Detection of unknown primary tumours in patients with cerebral metastases using whole-body 18F-flouorodeoxyglucose positron emission tomography

    DEFF Research Database (Denmark)

    Klee, B; Law, I; Højgaard, L

    2002-01-01

    Identification of the unknown primary tumours in patients presenting with cerebral metastasis is a continued diagnostic challenge. Despite extensive and lengthy diagnostic work-up, the primary tumours will remain obscure in a significant proportion of the patients. The aim of this study was to ev...

  2. Short-wavelength electrostatic waves in the earth's magnetosheath

    International Nuclear Information System (INIS)

    Gallagher, D.L.

    1985-01-01

    Recent observations with the ISEE 1 spacecraft have found electric field emissions in the dayside magnetosheath whose frequency spectrum is modulated at twice the spacecraft spin period. The upper frequency cutoff in the frequency-time spectrum of the emission has a characteristic parabola shape or ''festoon'' shape. The low-frequency cutoff ranges from 100 to 400 Hz, while the high-frequency limit ranges from about 1 to 4 kHz. The bandwidth is found to minimize for antenna orientations parallel to the wave vectors. The wave vector does not appear to be related to the local magnetic field, the plasma flow velocity, or the spacecraft-sun directions. The spacecraft observed frequency spectrum results from the spacecraft antenna response to the Doppler-shifted wave vector spectrum which exists in the plasma. Imposed constraints on the plasma rest frame wave vectors and frequencies indicate that emissions occur within the frequency range from about 150 Hz to 1 kHz, with wavelengths between about 40 and 600 m. These constraints strongly suggest that the festoon-shaped emissions are ion-acoustic waves. The small group velocity and k direction of the ion-acoustic mode are consistent with wave generation upstream at the bow shock and convection downstream to locations within the outer dayside magnetosheath

  3. Short wavelength electrostatic waves in the earth's magnetosheath

    International Nuclear Information System (INIS)

    Gallagher, D.L.

    1982-01-01

    Recent observations with the ISEE-1 spacecraft have found electric field emissions in the dayside magnetosheath whose frequency spectrum is modulated at twice the spacecraft spin period. The upper frequency cutoff in the frequency-time spectrum of the emissions has a characteristic parabola shape or ''festoon'' shape. The low frequency cutoff ranges from 100 Hz to 400 Hz, while the high frequency limit ranges from about 1kHz to 4kHz. The bandwidth is found to minimize for antenna orientations parallel to these wave number vectors, requiring the confinement of those vectors to a plane which contains the geocentric solar eclilptic coordinate z-axis. The spacecraft observed frequency spectrum results from the spacecraft antenna response to the Doppler shifted wave vector spectrum which exists in the plasma. Imposed constraints on the plasma rest-frame wave vectors and frequencies indicate that the emissions occur within the frequency range from about 150 Hz to 1 kHz, with wavelengths between about 30 meters and 600 meters. These constraints strongly suggest that the festoon-shaped emissions are ion-acoustic waves. The small group velocity and k vector direction of the ion-acoustic mode are consistent with wave generation upstream at the bow shock and convection downstream to locations within the outer dayside magnetosheath

  4. Optimization of dual-wavelength intravascular photoacoustic imaging of atherosclerotic plaques using Monte Carlo optical modeling

    Science.gov (United States)

    Dana, Nicholas; Sowers, Timothy; Karpiouk, Andrei; Vanderlaan, Donald; Emelianov, Stanislav

    2017-10-01

    Coronary heart disease (the presence of coronary atherosclerotic plaques) is a significant health problem in the industrialized world. A clinical method to accurately visualize and characterize atherosclerotic plaques is needed. Intravascular photoacoustic (IVPA) imaging is being developed to fill this role, but questions remain regarding optimal imaging wavelengths. We utilized a Monte Carlo optical model to simulate IVPA excitation in coronary tissues, identifying optimal wavelengths for plaque characterization. Near-infrared wavelengths (≤1800 nm) were simulated, and single- and dual-wavelength data were analyzed for accuracy of plaque characterization. Results indicate light penetration is best in the range of 1050 to 1370 nm, where 5% residual fluence can be achieved at clinically relevant depths of ≥2 mm in arteries. Across the arterial wall, fluence may vary by over 10-fold, confounding plaque characterization. For single-wavelength results, plaque segmentation accuracy peaked at 1210 and 1720 nm, though correlation was poor (blood, a primary and secondary wavelength near 1210 and 1350 nm, respectively, may offer the best implementation of dual-wavelength IVPA imaging. These findings could guide the development of a cost-effective clinical system by highlighting optimal wavelengths and improving plaque characterization.

  5. Multi-wavelength lasers using AWGs

    NARCIS (Netherlands)

    Besten, den J.H.

    2003-01-01

    Multiwavelength lasers using AWGs can be used as digitally tunable lasers with simple channel selection, and for generating multiple wavelengths simultanously. In this paper a number of different configurations is reviewed.

  6. Wavelength-tunable colloidal quantum dot laser on ultra-thin flexible glass

    Energy Technology Data Exchange (ETDEWEB)

    Foucher, C.; Guilhabert, B.; Laurand, N.; Dawson, M. D. [Institute of Photonics, SUPA, University of Strathclyde, Glasgow (United Kingdom)

    2014-04-07

    A mechanically flexible and wavelength-tunable laser with an ultra-thin glass membrane as substrate is demonstrated. The optically pumped hybrid device has a distributed feedback cavity that combines a colloidal quantum dot gain film with a grating-patterned polymeric underlayer, all on a 30-μm thick glass sheet. The total thickness of the structure is only 75 μm. The hybrid laser has an average threshold fluence of 450 ± 80 μJ/cm{sup 2} (for 5-ns excitation pulses) at an emitting wavelength of 607 nm. Mechanically bending the thin-glass substrate enables continuous tuning of the laser emission wavelength over an 18-nm range, from 600 nm to 618 nm. The correlation between the wavelength tunability and the mechanical properties of the thin laser structure is verified theoretically and experimentally.

  7. Wavelength interrogation of fiber Bragg grating sensors using tapered hollow Bragg waveguides.

    Science.gov (United States)

    Potts, C; Allen, T W; Azar, A; Melnyk, A; Dennison, C R; DeCorby, R G

    2014-10-15

    We describe an integrated system for wavelength interrogation, which uses tapered hollow Bragg waveguides coupled to an image sensor. Spectral shifts are extracted from the wavelength dependence of the light radiated at mode cutoff. Wavelength shifts as small as ~10  pm were resolved by employing a simple peak detection algorithm. Si/SiO₂-based cladding mirrors enable a potential operational range of several hundred nanometers in the 1550 nm wavelength region for a taper length of ~1  mm. Interrogation of a strain-tuned grating was accomplished using a broadband amplified spontaneous emission (ASE) source, and potential for single-chip interrogation of multiplexed sensor arrays is demonstrated.

  8. Wavelength mismatch effect in electromagnetically induced absorption

    Energy Technology Data Exchange (ETDEWEB)

    Bharti, Vineet [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Wasan, Ajay [Department of Physics, Indian Institute of Technology, Roorkee 247667 (India); Natarajan, Vasant [Department of Physics, Indian Institute of Science, Bangalore 560012 (India)

    2016-07-15

    We present a theoretical investigation of the phenomenon of electromagnetically induced absorption (EIA) in a 4-level system consisting of vee and ladder subsystems. The four levels are coupled using one weak probe field, and two strong control fields. We consider an experimental realization using energy levels of Rb. This necessitates dealing with different conditions of wavelength mismatch—near-perfect match where all three wavelengths are approximately equal; partial mismatch where the wavelength of one control field is less than the other fields; and complete mismatch where all three wavelengths are unequal. We present probe absorption profiles with Doppler averaging at room temperature to account for experiments in a room temperature Rb vapor cell. Our analysis shows that EIA resonances can be studied using Rydberg states excited with diode lasers. - Highlights: • Wavelength mismatch effect is investigated in electromagnetically induced absorption (EIA). • An experimental realization of 4-level vee + ladder system using energy levels of rubidium atom is presented. • EIA resonances are studied under different conditions of wavelength mismatch. • Possibility of observation of EIA using Rydberg states excited with diode lasers.

  9. Wavelength mismatch effect in electromagnetically induced absorption

    International Nuclear Information System (INIS)

    Bharti, Vineet; Wasan, Ajay; Natarajan, Vasant

    2016-01-01

    We present a theoretical investigation of the phenomenon of electromagnetically induced absorption (EIA) in a 4-level system consisting of vee and ladder subsystems. The four levels are coupled using one weak probe field, and two strong control fields. We consider an experimental realization using energy levels of Rb. This necessitates dealing with different conditions of wavelength mismatch—near-perfect match where all three wavelengths are approximately equal; partial mismatch where the wavelength of one control field is less than the other fields; and complete mismatch where all three wavelengths are unequal. We present probe absorption profiles with Doppler averaging at room temperature to account for experiments in a room temperature Rb vapor cell. Our analysis shows that EIA resonances can be studied using Rydberg states excited with diode lasers. - Highlights: • Wavelength mismatch effect is investigated in electromagnetically induced absorption (EIA). • An experimental realization of 4-level vee + ladder system using energy levels of rubidium atom is presented. • EIA resonances are studied under different conditions of wavelength mismatch. • Possibility of observation of EIA using Rydberg states excited with diode lasers.

  10. An organic white light-emitting dye: very small molecular architecture displays panchromatic emission.

    Science.gov (United States)

    Nandhikonda, Premchendar; Heagy, Michael D

    2010-11-14

    The synthesis and photophysical characterization of a new white-light fluorophore is described. The optimization of excitation wavelengths allows the naphthalimide (NI) dyes to display blue, green or white light emission depending on the excitation wavelength.

  11. Incidence of the geometric parameters and of flow in the primary ventilation rate and of carbon monoxide emissions in burning atmospherics of medium and high pressure

    International Nuclear Information System (INIS)

    Amell A, Andres; Hernandez V, Jaime; Cortes T, Jaime

    2000-01-01

    In this kind of atmospheric burners, high-pressure gas supply and Venturi geometry guarantee a good primary air entrance for combustion. In this project we analyze the most important burner geometric parameters (outlet diameter, injection diameter and mixer geometry) and gas flux conditions (supply pressure) that have an influence over primary aeration rate. The results of this investigation will contribute with the methodology design improvement, focused to use this kind of burners in our country

  12. Regional glucose hypometabolic spread within the primary motor cortex is associated with amyotrophic lateral sclerosis disease progression: A fluoro-deoxyglucose positron emission tomography study

    Directory of Open Access Journals (Sweden)

    Hironobu Endo

    2017-03-01

    Conclusions: In patients with ALS, glucose metabolism decreased in the impaired side of the primary motor cortex depending on the clinical symptom progression in the corresponding extremities, regardless of the presence of clinical UMN signs. A decrement in glucose metabolism on FDG-PET corresponding to symptoms in the primary motor cortex might be an indicator of the time-dependent course of ALS neurodegeneration.

  13. A 12 GHz wavelength spacing multi-wavelength laser source for wireless communication systems

    Science.gov (United States)

    Peng, P. C.; Shiu, R. K.; Bitew, M. A.; Chang, T. L.; Lai, C. H.; Junior, J. I.

    2017-08-01

    This paper presents a multi-wavelength laser source with 12 GHz wavelength spacing based on a single distributed feedback laser. A light wave generated from the distributed feedback laser is fed into a frequency shifter loop consisting of 50:50 coupler, dual-parallel Mach-Zehnder modulator, optical amplifier, optical filter, and polarization controller. The frequency of the input wavelength is shifted and then re-injected into the frequency shifter loop. By re-injecting the shifted wavelengths multiple times, we have generated 84 optical carriers with 12 GHz wavelength spacing and stable output power. For each channel, two wavelengths are modulated by a wireless data using the phase modulator and transmitted through a 25 km single mode fiber. In contrast to previously developed schemes, the proposed laser source does not incur DC bias drift problem. Moreover, it is a good candidate for radio-over-fiber systems to support multiple users using a single distributed feedback laser.

  14. Wavelength converter placement for different RWA algorithms in wavelength-routed all-optical networks

    Science.gov (United States)

    Chu, Xiaowen; Li, Bo; Chlamtac, Imrich

    2002-07-01

    Sparse wavelength conversion and appropriate routing and wavelength assignment (RWA) algorithms are the two key factors in improving the blocking performance in wavelength-routed all-optical networks. It has been shown that the optimal placement of a limited number of wavelength converters in an arbitrary mesh network is an NP complete problem. There have been various heuristic algorithms proposed in the literature, in which most of them assume that a static routing and random wavelength assignment RWA algorithm is employed. However, the existing work shows that fixed-alternate routing and dynamic routing RWA algorithms can achieve much better blocking performance. Our study in this paper further demonstrates that the wavelength converter placement and RWA algorithms are closely related in the sense that a well designed wavelength converter placement mechanism for a particular RWA algorithm might not work well with a different RWA algorithm. Therefore, the wavelength converter placement and the RWA have to be considered jointly. The objective of this paper is to investigate the wavelength converter placement problem under fixed-alternate routing algorithm and least-loaded routing algorithm. Under the fixed-alternate routing algorithm, we propose a heuristic algorithm called Minimum Blocking Probability First (MBPF) algorithm for wavelength converter placement. Under the least-loaded routing algorithm, we propose a heuristic converter placement algorithm called Weighted Maximum Segment Length (WMSL) algorithm. The objective of the converter placement algorithm is to minimize the overall blocking probability. Extensive simulation studies have been carried out over three typical mesh networks, including the 14-node NSFNET, 19-node EON and 38-node CTNET. We observe that the proposed algorithms not only outperform existing wavelength converter placement algorithms by a large margin, but they also can achieve almost the same performance comparing with full wavelength

  15. Observations of primary and secondary emissions in a B747 exhaust plume in the upper troposphere and inferred engine exit plane OH concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Schlager, H; Schulte, P; Tremmel, H G; Ziereis, H [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Arnold, F; Droste-Franke, B; Klemm, M; Schneider, J [Max-Planck-Inst. fuer Kernphysik, Heidelberg (Germany)

    1998-12-31

    The speciation of NO{sub y} exhaust emissions in the near-field plume of a B747 cruising at 9.2 km was measured in situ using the DLR Falcon research aircraft instrumented with a chemical ionisation mass spectrometer of MPI-K and a chemiluminescence NO detector of DLR. In addition, CO{sub 2} was measured providing a dilution factor for the exhaust species. Observed maximum peak concentrations above background in the plume 60 s after emission were 25.4 ppmv (CO{sub 2}), 184 ppbv (NO), 2.6 ppbv (HNO{sub 2}), and 1.3 ppbv (HNO{sub 3}). The observations were used to infer the initial OH concentration (15.4 ppmv) and NO{sub 2}/NO{sub x} ratio (0.08) at the engine exit by back calculations using a chemistry box model. (author) 20 refs.

  16. Observations of primary and secondary emissions in a B747 exhaust plume in the upper troposphere and inferred engine exit plane OH concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Schlager, H.; Schulte, P.; Tremmel, H.G.; Ziereis, H. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Arnold, F.; Droste-Franke, B.; Klemm, M.; Schneider, J. [Max-Planck-Inst. fuer Kernphysik, Heidelberg (Germany)

    1997-12-31

    The speciation of NO{sub y} exhaust emissions in the near-field plume of a B747 cruising at 9.2 km was measured in situ using the DLR Falcon research aircraft instrumented with a chemical ionisation mass spectrometer of MPI-K and a chemiluminescence NO detector of DLR. In addition, CO{sub 2} was measured providing a dilution factor for the exhaust species. Observed maximum peak concentrations above background in the plume 60 s after emission were 25.4 ppmv (CO{sub 2}), 184 ppbv (NO), 2.6 ppbv (HNO{sub 2}), and 1.3 ppbv (HNO{sub 3}). The observations were used to infer the initial OH concentration (15.4 ppmv) and NO{sub 2}/NO{sub x} ratio (0.08) at the engine exit by back calculations using a chemistry box model. (author) 20 refs.

  17. Role of whole body positron emission tomography/computed tomography scan with 18F-fluorodeoxyglucose in patients with biopsy proven tumor metastases from unknown primary site

    International Nuclear Information System (INIS)

    Pelosi, E.; Pennone, M.; Deandreis, D.; Bisi, G.

    2006-01-01

    Aim: The aim of this study was to evaluate the role of whole body PET/CT scan with 1 8F -fluorodeoxyglucose (FDG) in the detection of the primary tumor in patients with metastatic cancer from unknown primary origin (CUP syndrome). Methods: Sixty-eight consecutive patients, with CUP syndrome (39 lymph nodes, 29 visceral biopsy proven tumor metastases), underwent a whole-body FDG-PET/CT study. All enrolled patients were unsuccessfully studied, within the previous month, with physical examination, laboratory tests and conventional diagnostic procedures. All the pathological findings identified at PET/CT scan and suspected for primaries, were further investigated. After PET study, the minimum follow-up period for the inclusion in the studied population was 3 months. Results: The primary tumor site was correctly identified by FDG-PET/CT in 24 patients (24/68, 35.3%): long (0-9). rino/oro-pharynx (n=6), pancreas (n=5), colon (n=2). uterus (n=2). In 5 cases, FDG-PET scan did not identify a primary pathological focus, which was subsequently detected by other diagnostic methods within 3 months. In 39 patients (39168, 57.4%), the primary tumor site was not localized. However, in 9 of them, FDG-PET/CT scan identified further unexpected metastases, modifying the stage of disease. Overall, the following oncological treatment was influenced by the PET scan, in a total of 33 patients (33/68, 48.5%). Conclusion: Our data strongly support the diagnostic contribution of whole body FDG-PET/CT scan in the evaluation of patients with CUP syndrome and suggest its use in an early phase of the diagnostic iter to optimize patient management

  18. Emission spectrum and relaxation kinetics of SO2 induced by 266 nm laser.

    Science.gov (United States)

    Zhang, Guiyin; Zhang, Lianshui; Jin, Yidong

    2010-09-15

    Laser induced fluorescence (LIF) emission spectrum of SO(2) in the range of 270.0-470.0 nm has been obtained with the quadruple harmonic output (266 nm) of a pulsed Nd:YAG laser as excitation source. The spectrum is composed of a continuous envelope in the short wavelength side, while it shows the character of banded structure superimposed on a continuous one in the long wavelength region. Fluorescence emission from the hybrid states of A(1)A(2)+B(1)B(1) and X(1)A(1)+B(1)B(1) forms the continuous envelope and phosphorescence emission from the triplet state a(3)B(1) forms the banded progression. It is also found that direct emission from laser excited states is very weak. The primary portion of the emission is from the energy levels populated by collision relaxation or collision induced intersystem crossing process. The harmonic frequencies and inharmonic coefficients of the symmetric stretching vibration and the bending vibration of X(1)A(1) state are derived from the ascription of the phosphorescence progression. Copyright 2010 Elsevier B.V. All rights reserved.

  19. Air pollution from motor vehicle emissions

    International Nuclear Information System (INIS)

    Petrushevska, Ljubica

    1996-01-01

    This paper presents some aspects of air pollution from motor vehicle emissions as: characteristic primary and secondary pollutants, dependence of the motor vehicle emission from the engine type; the relationship of typical engine emission and performance to air-fuel ratio, transport of pollutants from mobile sources of emissions, as well as some world experiences in the control approaches for exhaust emissions. (author)

  20. Positron emission tomography (PET) and magnetic resonance imaging (MRI) for assessing tumour resectability in advanced epithelial ovarian, fallopian tube and/or primary peritoneal cancer

    NARCIS (Netherlands)

    Hoogendam, Jacob P.; Roze, Joline F.; van de Wetering, Fleur T.; Spijker, René; Verleye, Leen; Vlayen, Joan; Veldhuis, Wouter B.; Scholten, Rob J P M; Zweemer, RP

    2017-01-01

    This is a protocol for a Cochrane Review (Diagnostic test accuracy). The objectives are as follows: To assess the diagnostic test accuracy of PET(-CT), conventional and diffusion-weighted MRI as an replacement or an add-on to abdominal CT, for predicting tumour resectability at primary debulking

  1. Wavelength division multiplexing a practical engineering guide

    CERN Document Server

    Grobe, Klaus

    2013-01-01

    In this book, Optical Wavelength Division Multiplexing (WDM) is approached from a strictly practical and application-oriented point of view. Based on the characteristics and constraints of modern fiber-optic components, transport systems and fibers, the text provides relevant rules of thumb and practical hints for technology selection, WDM system and link dimensioning, and also for network-related aspects such as wavelength assignment and resilience mechanisms. Actual 10/40 Gb/s WDM systems are considered, and a preview of the upcoming 100 Gb/s systems and technologies for even higher bit rate

  2. Wavelength dependence of superhumps in VW Hyi

    International Nuclear Information System (INIS)

    Amerongen, S. van; Bovenschen, H.; Paradijs, J. van

    1987-01-01

    Results are presented of five-colour photometric observations of the SU UMa system VW Hyi, made on six nights during the November 1984 superoutburst. The light curve is dominated by superhump variations, whose amplitude in all passbands decreases with time (in the V-band from 0.16 mag about 4.5 day after the superoutburst reached maximum brightness, to 0.10 mag about 5 day later). The superhump light curve depends strongly on wavelength. In particular it appears that the light curves in different passbands are mutually shifted: the larger the wavelength, the more the light curve is delayed. (author)

  3. Short wavelength sources and atoms and ions

    International Nuclear Information System (INIS)

    Kennedy, E.T.

    2008-01-01

    The interaction of ionizing radiation with atoms and ions is a key fundamental process. Experimental progress has depended in particular on the development of short wavelength light sources. Laser-plasma and synchrotron sources have been exploited for several decades and most recently the development of short wavelength Free Electron Laser (FEL) sources is revolutionizing the field. This paper introduces laser plasma and synchrotron sources through examples of their use in studies of the interaction of ionizing radiation with atoms and ions, ranging from few-electron atomic and ionic systems to the many-electron high atomic number actinides. The new FEL source (FLASH) at DESY is introduced. (author)

  4. CONFIRMING THE PRIMARILY SMOOTH STRUCTURE OF THE VEGA DEBRIS DISK AT MILLIMETER WAVELENGTHS

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, A. Meredith; Plambeck, Richard; Chiang, Eugene [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Wilner, David J.; Andrews, Sean M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Mason, Brian [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States); Carpenter, John M. [California Institute of Technology, Department of Astronomy, MC 105-24, Pasadena, CA 91125 (United States); Chiang, Hsin-Fang [Institute for Astronomy, University of Hawaii, 640 North Aohoku Place, Hilo, HI 96720 (United States); Williams, Jonathan P. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Hales, Antonio [Joint ALMA Observatory, Av. El Golf 40, Piso 18, Santiago (Chile); Su, Kate [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Dicker, Simon; Korngut, Phil; Devlin, Mark, E-mail: mhughes@astro.berkeley.edu [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States)

    2012-05-01

    Clumpy structure in the debris disk around Vega has been previously reported at millimeter wavelengths and attributed to concentrations of dust grains trapped in resonances with an unseen planet. However, recent imaging at similar wavelengths with higher sensitivity has disputed the observed structure. We present three new millimeter-wavelength observations that help to resolve the puzzling and contradictory observations. We have observed the Vega system with the Submillimeter Array (SMA) at a wavelength of 880 {mu}m and an angular resolution of 5''; with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) at a wavelength of 1.3 mm and an angular resolution of 5''; and with the Green Bank Telescope (GBT) at a wavelength of 3.3 mm and angular resolution of 10''. Despite high sensitivity and short baselines, we do not detect the Vega debris disk in either of the interferometric data sets (SMA and CARMA), which should be sensitive at high significance to clumpy structure based on previously reported observations. We obtain a marginal (3{sigma}) detection of disk emission in the GBT data; the spatial distribution of the emission is not well constrained. We analyze the observations in the context of several different models, demonstrating that the observations are consistent with a smooth, broad, axisymmetric disk with inner radius 20-100 AU and width {approx}> 50 AU. The interferometric data require that at least half of the 860 {mu}m emission detected by previous single-dish observations with the James Clerk Maxwell Telescope be distributed axisymmetrically, ruling out strong contributions from flux concentrations on spatial scales of {approx}<100 AU. These observations support recent results from the Plateau de Bure Interferometer indicating that previous detections of clumpy structure in the Vega debris disk were spurious.

  5. CONFIRMING THE PRIMARILY SMOOTH STRUCTURE OF THE VEGA DEBRIS DISK AT MILLIMETER WAVELENGTHS

    International Nuclear Information System (INIS)

    Hughes, A. Meredith; Plambeck, Richard; Chiang, Eugene; Wilner, David J.; Andrews, Sean M.; Mason, Brian; Carpenter, John M.; Chiang, Hsin-Fang; Williams, Jonathan P.; Hales, Antonio; Su, Kate; Dicker, Simon; Korngut, Phil; Devlin, Mark

    2012-01-01

    Clumpy structure in the debris disk around Vega has been previously reported at millimeter wavelengths and attributed to concentrations of dust grains trapped in resonances with an unseen planet. However, recent imaging at similar wavelengths with higher sensitivity has disputed the observed structure. We present three new millimeter-wavelength observations that help to resolve the puzzling and contradictory observations. We have observed the Vega system with the Submillimeter Array (SMA) at a wavelength of 880 μm and an angular resolution of 5''; with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) at a wavelength of 1.3 mm and an angular resolution of 5''; and with the Green Bank Telescope (GBT) at a wavelength of 3.3 mm and angular resolution of 10''. Despite high sensitivity and short baselines, we do not detect the Vega debris disk in either of the interferometric data sets (SMA and CARMA), which should be sensitive at high significance to clumpy structure based on previously reported observations. We obtain a marginal (3σ) detection of disk emission in the GBT data; the spatial distribution of the emission is not well constrained. We analyze the observations in the context of several different models, demonstrating that the observations are consistent with a smooth, broad, axisymmetric disk with inner radius 20-100 AU and width ∼> 50 AU. The interferometric data require that at least half of the 860 μm emission detected by previous single-dish observations with the James Clerk Maxwell Telescope be distributed axisymmetrically, ruling out strong contributions from flux concentrations on spatial scales of ∼<100 AU. These observations support recent results from the Plateau de Bure Interferometer indicating that previous detections of clumpy structure in the Vega debris disk were spurious.

  6. Brightness temperature of the ''quiet'' Sun in the millimeter wavelength range

    International Nuclear Information System (INIS)

    Pelyushenko, S.A.

    1982-01-01

    Results are presented of recalibration of the data available for measurements of the solar brightness temperature Tsub(s) made by comparison with the lunar radio emission. A spectrum has been obtained of the ''quiet'' Sun radio emission in the range of 1-20 mm. The mean square spread of data does not exceed +-(from 3 to 4)%. The ''quiet'' Sun spectrum has a form of: Tsub(c)=(6150+-70)lambdasup(01+-0.01)[mm]K in the wavelength interval of lambda=(1-6) mm and Tsub(c)=(3470+-80)lambdasup(0.42+-0.01) [mm]K in the wavelength interval of lambda=(7-20) mm on approximation of recalibrated values of Tsub(c) with a linear dependence using the mean-square-root method. The obtained spectral characteristics of the ''quiet'' Sun radio frequency emission in the mullimeter wavelength range testify on the spectrum flatteming in the (1-6) mm wavelength range

  7. Solar Prominence Modelling and Plasma Diagnostics at ALMA Wavelengths

    Science.gov (United States)

    Rodger, Andrew; Labrosse, Nicolas

    2017-09-01

    Our aim is to test potential solar prominence plasma diagnostics as obtained with the new solar capability of the Atacama Large Millimeter/submillimeter Array (ALMA). We investigate the thermal and plasma diagnostic potential of ALMA for solar prominences through the computation of brightness temperatures at ALMA wavelengths. The brightness temperature, for a chosen line of sight, is calculated using the densities of electrons, hydrogen, and helium obtained from a radiative transfer code under non-local thermodynamic equilibrium (non-LTE) conditions, as well as the input internal parameters of the prominence model in consideration. Two distinct sets of prominence models were used: isothermal-isobaric fine-structure threads, and large-scale structures with radially increasing temperature distributions representing the prominence-to-corona transition region. We compute brightness temperatures over the range of wavelengths in which ALMA is capable of observing (0.32 - 9.6 mm), however, we particularly focus on the bands available to solar observers in ALMA cycles 4 and 5, namely 2.6 - 3.6 mm (Band 3) and 1.1 - 1.4 mm (Band 6). We show how the computed brightness temperatures and optical thicknesses in our models vary with the plasma parameters (temperature and pressure) and the wavelength of observation. We then study how ALMA observables such as the ratio of brightness temperatures at two frequencies can be used to estimate the optical thickness and the emission measure for isothermal and non-isothermal prominences. From this study we conclude that for both sets of models, ALMA presents a strong thermal diagnostic capability, provided that the interpretation of observations is supported by the use of non-LTE simulation results.

  8. Optical emissions from oxygen atom reactions with adsorbates

    Science.gov (United States)

    Oakes, David B.; Fraser, Mark E.; Gauthier-Beals, Mitzi; Holtzclaw, Karl W.; Malonson, Mark; Gelb, Alan H.

    1992-12-01

    Although most optical materials are inert to the ambient low earth orbit environment, high velocity oxygen atoms will react with adsorbates to produce optical emissions from the ultraviolet into the infrared. The adsorbates arise from chemical releases or outgassing from the spacecraft itself. We have been investigating kinetic and spectral aspects of these phenomenon by direct observation of the 0.2 to 13 micrometers chemiluminescence from the interaction of a fast atomic oxygen beam with a continuously dosed surface. The dosing gases include fuels, combustion products and outgassed species such as unsymmetrical dimethylhydrazine (UDMH), NO, H2O and CO. The surface studied include gold and magnesium fluoride. In order to relate the results to actual spacecraft conditions these phenomena have been explored as a function of O atom velocity, dosant flux and substrate temperature. UDMH dosed surfaces exhibit spectra typical (wavelength and intensity) of carbonaceous surfaces. The primary emitters are CO, CO2, and OH. H2O dosed surfaces are dominated by OH and /or H2O emission while CO dosed surfaces are dominated by CO and CO2 emissions. The nitric oxide dosed surface produces a glow from 0.4 to 5.4 micrometers due to NO2* continuum emission. The emission was observed to increase by a factor of two upon cooling the surface from 20 degree(s)C to -35 degree(s)C.

  9. Energy Levels, wavelengths and hyperfine structure measurements of Sc II

    Science.gov (United States)

    Hala, Fnu; Nave, Gillian

    2018-01-01

    Lines of singly ionized Scandium (Sc II) along with other Iron group elements have been observed [1] in the region surrounding the massive star Eta Carinae [2,3] called the strontium filament (SrF). The last extensive analysis of Sc II was the four-decade old work of Johansson & Litzen [4], using low-resolution grating spectroscopy. To update and extend the Sc II spectra, we have made observation of Sc/Ar, Sc/Ne and Sc/Ge/Ar hollow cathode emission spectrum on the NIST high resolution FT700 UV/Vis and 2 m UV/Vis/IR Fourier transform spectrometers (FTS). More than 850 Sc II lines have been measured in the wavelength range of 187 nm to 3.2 μm. connecting a total of 152 energy levels. The present work also focuses to resolve hyperfine structure (HFS) in Sc II lines. We aim to obtain accurate transition wavelengths, improved energy levels and HFS constants of Sc II. The latest results from work in progress will be presented.Reference[1] Hartman H, Gull T, Johansson S and Smith N 2004 Astron. Astrophys. 419 215[2] Smith N, Morse J A and Gull T R 2004 Astrophys. J. 605 405[3] Davidson K and Humphreys R M 1997 Annu. Rev. Astron. Astrophys. 35[4] Johansson S and Litzén U 1980 Phys. Scr. 22 49

  10. Multi-client quantum key distribution using wavelength division multiplexing

    International Nuclear Information System (INIS)

    Grice, Warren P.; Bennink, Ryan S.; Earl, Dennis Duncan; Evans, Philip G.; Humble, Travis S.; Pooser, Raphael C.; Schaake, Jason; Williams, Brian P.

    2011-01-01

    Quantum Key Distribution (QKD) exploits the rules of quantum mechanics to generate and securely distribute a random sequence of bits to two spatially separated clients. Typically a QKD system can support only a single pair of clients at a time, and so a separate quantum link is required for every pair of users. We overcome this limitation with the design and characterization of a multi-client entangled-photon QKD system with the capacity for up to 100 clients simultaneously. The time-bin entangled QKD system includes a broadband down-conversion source with two unique features that enable the multi-user capability. First, the photons are emitted across a very large portion of the telecom spectrum. Second, and more importantly, the photons are strongly correlated in their energy degree of freedom. Using standard wavelength division multiplexing (WDM) hardware, the photons can be routed to different parties on a quantum communication network, while the strong spectral correlations ensure that each client is linked only to the client receiving the conjugate wavelength. In this way, a single down-conversion source can support dozens of channels simultaneously--and to the extent that the WDM hardware can send different spectral channels to different clients, the system can support multiple client pairings. We will describe the design and characterization of the down-conversion source, as well as the client stations, which must be tunable across the emission spectrum.

  11. Single-photon generator for optical telecommunication wavelength

    International Nuclear Information System (INIS)

    Usuki, T; Sakuma, Y; Hirose, S; Takemoto, K; Yokoyama, N; Miyazawa, T; Takatsu, M; Arakawa, Y

    2006-01-01

    We report on the generation of single-photon pulses from a single InAs/InP quantum dot in telecommunication bands (1.3-1.55 μm: higher transmittance through an optical fiber). First we prepared InAs quantum dots on InP (0 0 1) substrates in a low-pressure MOCVD by using a so-called InP 'double-cap' procedure. The quantum dots have well-controlled photo emission wavelength in the telecommunication bands. We also developed a single-photon emitter in which quantum dots were embedded. Numerical simulation designed the emitter to realize efficient injection of the emitted photons into a single-mode optical fiber. Using a Hanbury-Brown and Twiss technique has proved that the photons through the fiber were single photons

  12. External-cavity high-power dual-wavelength tapered amplifier with tunable THz frequency difference

    DEFF Research Database (Denmark)

    Chi, Mingjun; Jensen, Ole Bjarlin; Petersen, Paul Michael

    2012-01-01

    A tunable 800 nm high-power dual-wavelength diode laser system with double-Littrow external-cavity feedback is demonstrated. The two wavelengths can be tuned individually, and the frequency difference of the two wavelengths is tunable from 0.5 to 5.0 THz. A maximum output power of 1.54 W is achie......A tunable 800 nm high-power dual-wavelength diode laser system with double-Littrow external-cavity feedback is demonstrated. The two wavelengths can be tuned individually, and the frequency difference of the two wavelengths is tunable from 0.5 to 5.0 THz. A maximum output power of 1.54 W...... is achieved with a frequency difference of 0.86 THz, the output power is higher than 1.3 W in the 5.0 THz range of frequency difference, and the amplified spontaneous emission intensity is more than 20 dB suppressed in the range of frequency difference. The beam quality factor M2 is 1.22±0.15 at an output...

  13. Prospective, blinded trial of whole-body magnetic resonance imaging versus computed tomography positron emission tomography in staging primary and recurrent cancer of the head and neck.

    LENUS (Irish Health Repository)

    O'Neill, J P

    2012-02-01

    OBJECTIVES: To compare the use of computed tomography - positron emission tomography and whole-body magnetic resonance imaging for the staging of head and neck cancer. PATIENTS AND METHODS: From January to July 2009, 15 consecutive head and neck cancer patients (11 men and four women; mean age 59 years; age range 19 to 81 years) underwent computed tomography - positron emission tomography and whole-body magnetic resonance imaging for pre-therapeutic evaluation. All scans were staged, as per the American Joint Committee on Cancer tumour-node-metastasis classification, by two blinded consultant radiologists, in two sittings. Diagnoses were confirmed by histopathological examination of endoscopic biopsies, and in some cases whole surgical specimens. RESULTS: Tumour staging showed a 74 per cent concordance, node staging an 80 per cent concordance and metastasis staging a 100 per cent concordance, comparing the two imaging modalities. CONCLUSION: This study found radiological staging discordance between the two imaging modalities. Whole-body magnetic resonance imaging is an emerging staging modality with superior visualisation of metastatic disease, which does not require exposure to ionising radiation.

  14. Wavelength comparison for laser induced breakdown spectroscopy caries detection

    Science.gov (United States)

    Amaral, Marcello M.; Raele, Marcus P.; Ana, Patrícia A.; Núñez, Sílvia C.; Zamataro, Claudia B.; Zezell, Denise M.

    2018-02-01

    Laser Induced Breakdown Spectroscopy (LIBS) is a technique capable to perform elemental analyses of a variety of samples, independent of matter state. Other spectroscopy techniques may require a destructive and time-consuming sample preparation. On the other hand, LIBS is a less destructive technique with no (or considerably less) sample preparation, using a relatively simple experimental setup. LIBS also provides a multielement analysis into one single spectrum acquisition, applying a Nd:YAG short-pulsed laser to ensure the stoichiometry between the sample and the generated plasma. LIBS have been applied on the study of carious lesions using a Nd:YAG into its fundamental emission at 1064 nm. It was shown that ratio of P/Ca and Zn/Ca can be used to monitor the cariogenic process. Another minor elements, e.g. C and Cu, associated with bacteria biofilm were also measured with the Nd:YAG laser. The fundamental wavelength emission (1064 nm) of Nd:YAG is coincident with a hydroxyapatite transmission window and it may affect the result. In order to address this issue a study used the second harmonic of the Nd:YAG laser at 532 nm. It was show that it is also possible perform LIBS on carious lesion using the Nd:YAG at 532 nm. However, there is not a work direct comparing the LIBS at 532 nm and 1064 nm for carious lesion detection. So, the aim of this work was to investigate the influence of laser wavelength on the LIBS performance for carious lesion detection. In both cases the carious lesion was detected with the advantage of no interference with hydroxyapatite at 532 nm.

  15. Topology Optimization of Sub-Wavelength Antennas

    DEFF Research Database (Denmark)

    Erentok, Aycan; Sigmund, Ole

    2011-01-01

    We propose a topology optimization strategy for the systematic design of a three-dimensional (3D), conductor-based sub-wavelength antenna. The post-processed finite-element (FE) models of the optimized structure are shown to be self-resonant, efficient and exhibit distorted omnidirectional...

  16. Characterization of ethanol concentrations at ultraviolet wavelength ...

    African Journals Online (AJOL)

    This paper presents the measurement of optical absorption spectrum for different concentrations of ethanol at ultraviolet wavelength. Ethanol absorption spectrum was measured using portable spectroscopy setup from Avantes. It consists of Balanced Deuterium Halogen light source and spectrometer. The light source can ...

  17. Smart wavelength meter for integrated photonics

    NARCIS (Netherlands)

    Benelajla, Meryem; Taballione, Caterina; Boller, Klaus J.

    2017-01-01

    Thermally tunable SiN waveguide microring resonators in connection with neural network readout algorithms appear promising for use as integrated optical wavelength meters. So far, we have observed long-term reliability and a temperature immunity of the readout across several degrees of ambient

  18. An automated wavelength selection for flame spectroscopy

    International Nuclear Information System (INIS)

    Hurteau, M.; Mislan, J.P.; Ashley, R.W.

    1976-01-01

    A simple electro-mechanical programming system is described for use with a flame spectrophotometer. Its application for automated sequential multi-element analysis is illustrated. Reproducibility of wavelength settings are within +-0.5 A. Precision and sensitivities are at least as good as those obtained for single element determinations. (author)

  19. Alien wavelength modeling tool and field trial

    DEFF Research Database (Denmark)

    Sambo, N.; Sgambelluri, A.; Secondini, M.

    2015-01-01

    A modeling tool is presented for pre-FEC BER estimation of PM-QPSK alien wavelength signals. A field trial is demonstrated and used as validation of the tool's correctness. A very close correspondence between the performance of the field trial and the one predicted by the modeling tool has been...

  20. Two-wavelength spatial-heterodyne holography

    Science.gov (United States)

    Hanson, Gregory R.; Bingham, Philip R.; Simpson, John T.; Karnowski, Thomas P.; Voelkl, Edgar

    2007-12-25

    Systems and methods are described for obtaining two-wavelength differential-phase holograms. A method includes determining a difference between a filtered analyzed recorded first spatially heterodyne hologram phase and a filtered analyzed recorded second spatially-heterodyned hologram phase.

  1. Continuum emission of excited sodium dimer

    International Nuclear Information System (INIS)

    Pardo, A.; Poyato, J.M.L.; Alonso, J.I.; Rico, F.R.

    1980-01-01

    A study has been made of the behaviour of excited molecular sodium using high-power Ar + laser radiation. A continuum emission was observed in the red wavelength region. This emission was thought to be caused by the formation of excited triatomic molecules. Energy transfer was observed from excited molecules to atoms. (orig.)

  2. A Case of Low-Grade Primary Cardiac Lymphoma with Pericardial Effusion Diagnosed by Combined 18F-Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography (FDG-PET/CT) Imaging and Effusion Cytology.

    Science.gov (United States)

    Fukunaga, Hisanori; Tatewaki, Yasuko; Mutoh, Tatsushi; Shimomura, Hideo; Yamamoto, Shuzo; Terao, Chiaki; Totsune, Tomoko; Nakagawa, Manabu; Taki, Yasuyuki

    2018-03-14

    BACKGROUND Primary cardiac lymphoma is rare and can be an aggressive disease, depending on the grade. A case is reported of low-grade primary cardiac lymphoma associated with a pericardial effusion. 18F-fluorodeoxyglucose positron emission tomography and computed tomography (FDG-PET/CT) imaging was useful in the diagnosis and in evaluating the disease activity in this case. CASE REPORT A 72-year-old Japanese woman visited a general practitioner, complaining of dyspnea associated with cardiac tamponade. Pericardiocentesis was performed, and Group V malignant cells were identified by cytology, suspicious for malignant lymphoma. Whole-body FDG-PET/CT scans showed no pleural effusion or lymph node metastasis supporting the diagnosis of primary cardiac lymphoma diagnosed on pericardial effusion. The laboratory investigations showed that levels of serum soluble interleukin-2 (IL-2) receptor (sIL-2R), a diagnostic and prognostic marker for malignant lymphoma, were not elevated (258 U/ml). A six-month follow-up FDG-PET/CT scan showed an increased volume of the pericardial effusion and mild but abnormal uptake diffusely in the pericardial space, and the sIL-2R was slightly elevated (860 U/ml). No abnormal FDG accumulation outside the retained pericardial effusion was noted, which was compatible with a clinical picture of low-grade primary cardiac lymphoma, and in a period of watchful waiting during the first two years later, the sIL-2R had reduced to 195 U/ml. CONCLUSIONS This is a rare case of low-grade primary cardiac lymphoma detected in a pericardial effusion, and highlights the utility of the FDG-PET/CT scan as a valuable diagnostic and follow-up modality.

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

    National Research Council Canada - National Science Library

    Hill, Steven C; Mayo, Michael W; Chang, Richard K

    2009-01-01

    The fluorescence intensity as a function of excitation and emission wavelengths (EEM spectra) was measured for different species of bacteria, biochemical constituents of cells, pollens, and vegetation...

  4. Development of monitoring system using acoustic emission for detection of helium gas leakage for primary cooling system and flow-induced vibration for heat transfer tube of heat exchangers for the High Temperature Engineering Test Reactor (HTTR)

    International Nuclear Information System (INIS)

    Tachibana, Yukio; Kunitomi, Kazuhiko; Furusawa, Takayuki; Shinozaki, Masayuki; Satoh, Yoshiyuki; Yanagibashi, Minoru

    1998-10-01

    The High Temperature Engineering Test Reactor (HTTR) uses helium gas for its primary coolant, whose leakage inside reactor containment vessel is considered in design of the HTTR. It is necessary to detect leakage of helium gas at an early stage so that total amount of the leakage should be as small as possible. On the other hand, heat transfer tubes of heat exchangers of the HTTR are designed not to vibrate at normal operation, but the flow-induced vibration is to be monitored to provide against an emergency. Thus monitoring system of acoustic emission for detection of primary coolant leakage and vibration of heat transfer tubes was developed and applied to the HTTR. Before the application to the HTTR, leakage detection test was performed using 1/4 scaled model of outer tube of primary concentric hot gas duct. Result of the test covers detectable minimum leakage rate and effect of difference in gas, pressure, shape of leakage path and distance from the leaking point. Detectable minimum leakage rate was about 5 Ncc/sec. The monitoring system is promising in leakage detection, though countermeasure to noise is to be needed after the HTTR starts operating. (author)

  5. Solid state cathodoluminescence and the properties of its two emission peaks

    International Nuclear Information System (INIS)

    Xu Xurong

    2007-01-01

    We discovered solid state cathodoluminescence (SSCL). For its identification we excluded all artifacts, carried out its cross proof and studied its generality. Its spectrum is characterized by the appearance of short wavelength peak when the applied voltage is increased. Three voltage ranges are distinguished, in the lower voltage range we have the long wavelength emission, in the middle range we have both long and short wavelength emissions, and in the higher voltage range we have only the short wavelength emission. The mechanism of this spectral shift lies in the electrical field ionization of excitons. This effect initiates the applicability of band model besides molecular excitons theory. The temporal behaviors of both peaks in SSCL are studied with a method of estimating lifetime by means of frequency dependence on intensity. The lifetime of short wavelength emission is found to be 5 ms and that of long wavelength emission is less than 0.05 ms

  6. CBET Experiments with Wavelength Shifting at the Nike Laser

    Science.gov (United States)

    Weaver, James; McKenty, P.; Bates, J.; Myatt, J.; Shaw, J.; Obenschain, K.; Oh, J.; Kehne, D.; Obenschain, S.; Lehmberg, R. H.; Tsung, F.; Schmitt, A. J.; Serlin, V.

    2016-10-01

    Studies conducted at NRL during 2015 searched for cross-beam energy transport (CBET) in small-scale plastic targets with strong gradients in planar, cylindrical, and spherical geometries. The targets were irradiated by two widely separated beam arrays in a geometry similar to polar direct drive. Data from these shots will be presented that show a lack of a clear CBET signature even with wavelength shifting of one set of beams. This poster will discuss the next campaign being planned, in part, with modelling codes developed at LLE. The next experiments will use a target configuration optimized to create stronger SBS growth. The primary path under consideration is to increase scale lengths 5-10x over the previous study by using exploding foils or low density foams. In addition to simulations, the presentation will also discuss improvements to the diagnostic suite and laser operations; for example, a new set of etalons will be available for the next campaign that should double the range of wavelength shifting between the two beam arrays. Work supported by DoE/NNSA.

  7. Design alternatives for wavelength routing networks

    Science.gov (United States)

    Miliotis, K.; Papadimitriou, G. I.; Pomportsis, A. S.

    2003-03-01

    This paper attempts to provide a high level overview of many of the technologies employed in optical networks with a focus on wavelength-routing networks. Optical networks involve a number of technologies from the physics of light through protocols and networks architectures. In fact there is so much technology and know-how that most people involved with optical networks only have a full understanding of the narrow area they deal with. We start first examining the principles that govern light and its use as a wave guide, and then turn our focus to the various components that constitute an optical network and conclude with the description of all optical networks and wavelength-routed networks in greater detail.

  8. 18F-fluorodeoxyglucose positron emission tomography/computed tomography for primary thyroid langerhans histiocytosis: A case report and literature review

    International Nuclear Information System (INIS)

    Long, Qi; Shaoyan, Wang; Hui, Wang

    2015-01-01

    Langerhans cell histiocytosis (LCH) is a rare clonal proliferative disease, with an incidence rate of 4.0–5.4/1 million individuals. LCH encompasses a spectrum of disorders with diverse clinical presentations ranging from a single organ to multiple organ involvement. LCH rarely involves the thyroid gland. We presented a case with LCH of thyroid gland. The patient had painless progressive neck enlargement and then diabetes insipidus. Ultrasonic scan and magnetic resonance imaging scan revealed nodular goiter and pituitary stalk enlargement, respectively. Histopathological analysis revealed features of histiocytoid cells. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) was performed in order to rule out the presence of whole body infiltration. 18F-FDG PET/CT also demonstrated increased uptake in the thickening pituitary stalk and maxillofacial skin lesion, in addition to the bilateral thyroid nodules, CT showed the left lung nodule and the skull destruction without 18F-FDG uptake. This report emphasizes the role of 18F-FDG PET/CT in multiple organs involvement of patients with LCH

  9. Primary central nervous system lymphoma in an human immunodeficiency virus-infected patient mimicking bilateral eye sign in brain seen in fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography.

    Science.gov (United States)

    Kamaleshwaran, Koramadai Karuppusany; Thirugnanam, Rajasekar; Shibu, Deepu; Kalarikal, Radhakrishnan Edathurthy; Shinto, Ajit Sugunan

    2014-04-01

    Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) has proven useful in the diagnosis, staging, and detection of metastasis and posttreatment monitoring of several malignancies in human immunodeficiency virus (HIV)-infected patients. It also has the ability to make the important distinction between malignancy and infection in the evaluation of central nervous system (CNS) lesions, leading to the initiation of the appropriate treatment and precluding the need for invasive biopsy. We report an interesting case of HIV positive 35-year-old woman presented with headache, disorientation, and decreased level of consciousness. She underwent whole body PET/CT which showed multiple lesions in the cerebrum which mimics bilateral eye in brain. A diagnosis of a primary CNS lymphoma was made and patient was started on chemotherapy.

  10. Primary central nervous system lymphoma in an human immunodeficiency virus-infected patient mimicking bilateral eye sign in brain seen in fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography

    International Nuclear Information System (INIS)

    Kamaleshwaran, Koramadai Karuppusany; Thirugnanam, Rajasekar; Shibu, Deepu; Kalarikal, Radhakrishnan Edathurthy; Shinto, Ajit Sugunan

    2014-01-01

    Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) has proven useful in the diagnosis, staging, and detection of metastasis and posttreatment monitoring of several malignancies in human immunodeficiency virus (HIV)-infected patients. It also has the ability to make the important distinction between malignancy and infection in the evaluation of central nervous system (CNS) lesions, leading to the initiation of the appropriate treatment and precluding the need for invasive biopsy. We report an interesting case of HIV positive 35-year-old woman presented with headache, disorientation, and decreased level of consciousness. She underwent whole body PET/CT which showed multiple lesions in the cerebrum which mimics bilateral eye in brain. A diagnosis of a primary CNS lymphoma was made and patient was started on chemotherapy

  11. Optical Detection in Ultrafast Short Wavelength Science

    International Nuclear Information System (INIS)

    Fullagar, Wilfred K.; Hall, Chris J.

    2010-01-01

    A new approach to coherent detection of ionising radiation is briefly motivated and recounted. The approach involves optical scattering of coherent light fields by colour centres in transparent solids. It has significant potential for diffractive imaging applications that require high detection dynamic range from pulsed high brilliance short wavelength sources. It also motivates new incarnations of Bragg's X-ray microscope for pump-probe studies of ultrafast molecular structure-dynamics.

  12. Short wavelength striations on expanding plasma clouds

    International Nuclear Information System (INIS)

    Winske, D.; Gary, S.P.

    1989-01-01

    The growth and evolution of short wavelength (< ion gyroradius) flute modes on a plasma expanding across an ambient magnetic field have been actively studied in recent years, both by means of experiments in the laboratory as well as in space and through numerical simulations. We review the relevant observations and simulations results, discuss the instability mechanism and related linear theory, and describe recent work to bring experiments and theory into better agreement. 30 refs., 6 figs

  13. Acoustic emission

    International Nuclear Information System (INIS)

    Nichols, R.W.

    1976-01-01

    The volume contains six papers which together provide an overall review of the inspection technique known as acoustic emission or stress wave emission. The titles are: a welder's introduction to acoustic emission technology; use of acoustic emission for detection of defects as they arise during fabrication; examples of laboratory application and assessment of acoustic emission in the United Kingdom; (Part I: acoustic emission behaviour of low alloy steels; Part II: fatigue crack assessment from proof testing and continuous monitoring); inspection of selected areas of engineering structures by acoustic emission; Japanese experience in laboratory and practical applications of acoustic emission to welded structures; and ASME acoustic emission code status. (U.K.)

  14. Optically coupled cavities for wavelength switching

    Energy Technology Data Exchange (ETDEWEB)

    Costazo-Caso, Pablo A; Granieri, Sergio; Siahmakoun, Azad, E-mail: pcostanzo@ing.unlp.edu.ar, E-mail: granieri@rose-hulman.edu, E-mail: siahmako@rose-hulman.edu [Department of Physics and Optical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803 (United States)

    2011-01-01

    An optical bistable device which presents hysteresis behavior is proposed and experimentally demonstrated. The system finds applications in wavelength switching, pulse reshaping and optical bistability. It is based on two optically coupled cavities named master and slave. Each cavity includes a semiconductor optical amplifier (SOA), acting as the gain medium of the laser, and two pair of fiber Bragg gratings (FBG) which define the lasing wavelength (being different in each cavity). Finally, a variable optical coupler (VOC) is employed to couple both cavities. Experimental characterization of the system performance is made analyzing the effects of the coupling coefficient between the two cavities and the driving current in each SOA. The properties of the hysteretic bistable curve and switching can be controlled by adjusting these parameters and the loss in the cavities. By selecting the output wavelength ({lambda}{sub 1} or {lambda}{sub 2}) with an external filter it is possible to choose either the invert or non-invert switched signal. Experiments were developed employing both optical discrete components and a photonic integrated circuit. They show that for 8 m-long cavities the maximum switching frequency is about 500 KHz, and for 4 m-long cavities a minimum rise-time about 21 ns was measured. The switching time can be reduced by shortening the cavity lengths and using photonic integrated circuits.

  15. Wavelength switching in an optical klystron

    International Nuclear Information System (INIS)

    Berryman, K.W.; Smith, T.I.

    1995-01-01

    A symmetric optical klystron consists of two identical undulator sections separated a dispersive section. For a device of a given length, an optical klystron is capable of producing much more bunching, and therefore more gain, than a traditional undulator. Another consequence of introducing dispersion between two undulator sections is that the overall spontaneous radiation pattern results from the interference between the two undulator sections, and as such resembles a standard undulator radiation pattern modulated by a sinusoidal interference term. The presence of several wavelength peaks in the spontaneous lineshape implies an equal number of peaks in the gain spectrum. If the strength of the dispersion section is adjusted to provide nearly equal gain on the two largest of these peaks, then they will compete, and the FEL may switch wavelengths based on noise, cavity length, or other perturbations. We provide the first observations of this behavior, using the FIREFLY system at the Stanford Picosecond FEL Center. In FIREFLY, relative wavelength switching by more than 3%--more than twice the laser linewidth-has been observed by varying dispersion section strength, while at intermediate points stable switching has also been observed as a function of cavity length

  16. Multiple wavelength X-ray monochromators

    International Nuclear Information System (INIS)

    Steinmeyer, P.A.

    1992-01-01

    An improved apparatus and method is provided for separating input x-ray radiation containing first and second x-ray wavelengths into spatially separate first and second output radiation which contain the first and second x-ray wavelengths, respectively. The apparatus includes a crystalline diffractor which includes a first set of parallel crystal planes, where each of the planes is spaced a predetermined first distance from one another. The crystalline diffractor also includes a second set of parallel crystal planes inclined at an angle with respect to the first set of crystal planes where each of the planes of the second set of parallel crystal planes is spaced a predetermined second distance from one another. In one embodiment, the crystalline diffractor is comprised of a single crystal. In a second embodiment, the crystalline diffractor is comprised of a stack of two crystals. In a third embodiment, the crystalline diffractor includes a single crystal that is bent for focusing the separate first and second output x-ray radiation wavelengths into separate focal points. 3 figs

  17. Dual-wavelength electroluminescence from an n-ZnO/p-GaN heterojunction light emitting diode

    International Nuclear Information System (INIS)

    Tsai, Bor-Sheng; Chiu, Hung-Jen; Chen, Tai-Hong; Lai, Li-Wen; Ho, Chai-Cheng; Liu, Day-Shan

    2015-01-01

    Highlights: • The LEDs fabricated by 450 °C- and 700 °C-annealed n-ZnO/p-GaN heterojunction structures were investigated. • The structure annealed at 700 °C emitted yellowish light composed of the dual-wavelength radiations centered at 420 and 610 nm. • The long-wavelength radiation was attributed to emerge from the deep-level emission and the Ga–O interlayer emission. - Abstract: We investigated the electro-optical properties of light emitting diodes (LEDs) fabricated by using the n-ZnO/p-GaN heterojunction structures annealed at 450 °C and 700 °C, in vacuum ambient. A dominant near-UV emission at approximately 420 nm was observed from the LED fabricated by the 450 °C-annealed n-ZnO/p-GaN heterojunction structure, whereas that of the structure annealed at 700 °C emitted a yellowish light composed of the dual-wavelength emissions centered at 420 and 610 nm. The mechanism responsible for the broad long-wavelength radiation was ascribed to the transitions associated with both the deep-level emissions due to the activation of the native defects on the n-ZnO side surface and the formation of the Ga–O interlayer resulting from the in-diffusion of oxygen atoms to the p-GaN side surface of the n-ZnO/p-GaN interface.

  18. Primary emissions and chemical oxidation of volatile organic compounds emitted from laboratory biomass burning sources during the 2016 FIREX FireLab campaign: measurements from a H3O+ chemical ionization mass spectrometer

    Science.gov (United States)

    Coggon, M. M.; Warneke, C.; Koss, A.; Sekimoto, K.; Yuan, B.; Lim, C. Y.; Hagan, D. H.; Kroll, J. H.; Cappa, C. D.; Gilman, J.; Lerner, B. M.; Jimenez, J. L.; Yokelson, R. J.; Roberts, J. M.; De Gouw, J. A.

    2017-12-01

    Non-methane organic gases (NMOG) emitted by biomass burning constitute a large source of reactive carbon in the atmosphere. Once emitted, these compounds may undergo series of reactions with the OH radical and nitrogen oxides to form secondary organic aerosol (SOA), ozone, or other health-impacting products. The complex emission profile and strong variability of biomass burning NMOG play an important, yet understudied, role in the variability of air quality outcomes such as SOA and ozone. In this study, we summarize measurements of biomass burning volatile organic compounds (VOCs) conducted using a H3O+ chemical ionization mass spectrometer (H3O+-CIMS) during the 2016 FIREX laboratory campaign in Missoula, MT. Specifically, we will present data demonstrating the chemical evolution of biomass burning VOCs artificially aged in a field-deployable photooxidation chamber and an oxidation flow reactor. More than 50 OH-oxidation experiments were conducted with biomass types representing a range of North American fuels. Across many fuel types, VOCs with high SOA and ozone formation potential, such as aromatics and furans, were observed to quickly react with the OH radical while oxidized species were generated. We compare the calculated OH reactivity of the primary emissions to the calculated OH reactivity used in many photochemical models and highlight areas requiring additional research in order to improve model/measurement comparisons.

  19. NOx emission reduction from gas turbines

    International Nuclear Information System (INIS)

    Groppi, G.; Lietti, L.; Forzatti, P.

    2001-01-01

    NO x emissions from gas turbines are a serious environmental concern. Primary control technologies significantly reduce NO x formation, which however is still too high to match increasingly strict emission laws. Catalytic processes can provide lower NO x emissions both as primary and secondary control methods, but their economics should be carefully addressed [it

  20. Predamage threshold electron emission from insulator and semiconductor surfaces

    International Nuclear Information System (INIS)

    Siekhaus, W.J.; Kinney, J.H.; Milam, D.

    1985-01-01

    Predamage electron emission shows a dependence on fluence, bandgap and wavelength consistent with multiphoton excitation across the bandgap and inconsistent with avalanche ionization and thermionic emission models. The electron emission scales with pulselength as 1/√T. 6 references, 8 figures, 1 table

  1. The Comparison of Computed Tomography Perfusion, Contrast-Enhanced Computed Tomography and Positron-Emission Tomography/Computed Tomography for the Detection of Primary Esophageal Carcinoma.

    Science.gov (United States)

    Genc, Berhan; Kantarci, Mecit; Sade, Recep; Orsal, Ebru; Ogul, Hayri; Okur, Aylin; Aydin, Yener; Karaca, Leyla; Eroğlu, Atilla

    2016-01-01

    The purpose of this study was to investigate the efficiency of computed tomography perfusion (CTP), contrast-enhanced computed tomography (CECT) and 18F-fluoro-2-deoxy-D-glucose (18F-FDG) positron-emission tomography (PET/CT) in the diagnosis of esophageal cancer. This prospective study consisted of 33 patients with pathologically confirmed esophageal cancer, 2 of whom had an esophageal abscess. All the patients underwent CTP, CECT and PET/CT imaging and the imaging findings were evaluated. Sensitivity, specificity and positive and negative predictive values were calculated for each of the 3 imaging modalities relative to the histological diagnosis. Thirty-three tumors were visualized on CTP, 29 on CECT and 27 on PET/CT. Six tumors were stage 1, and 2 and 4 of these tumors were missed on CECT and PET/CT, respectively. Significant differences between CTP and CECT (p = 0.02), and between CTP and PET/CT (p = 0.04) were found for stage 1 tumors. Values for the sensitivity, specificity and positive and negative predictive values on CTP were 100, 100, 100 and 100%, respectively. Corresponding values on CECT were 93.94, 0, 93.94 and 0%, respectively, and those on PET/CT were 87.88, 0, 93.55 and 0%, respectively. Hence, the sensitivity, specificity and positive and negative predictive values of CTP were better than those of CECT and PET/CT. CTP had an advantage over CECT and PET/CT in detecting small lesions. CTP was valuable, especially in detecting stage 1 tumors. © 2016 S. Karger AG, Basel.

  2. The wavelength dependence of gold nanorod-mediated optical breakdown during infrared ultrashort pulses

    Energy Technology Data Exchange (ETDEWEB)

    Davletshin, Yevgeniy R.; Kumaradas, J. Carl [Department of Physics, Ryerson University, Toronto, ON (Canada)

    2017-04-15

    This paper investigates the wavelength dependence of the threshold of gold nanorod-mediated optical breakdown during picosecond and femtosecond near infrared optical pulses. It was found that the wavelength dependence in the picosecond regime is governed solely by the changes of a nanorod's optical properties. On the other hand, the optical breakdown threshold during femtosecond pulse exposure falls within one of two regimes. When the ratio of the maximum electric field from the outside to the inside of the nanorod is less then 7 (the absorption regime) the seed electrons are initiated by photo-thermal emission, and the wavelength dependence in the threshold of optical breakdown is the result of optical properties of the nanoparticle. When the ratio is greater than 7 (the near-field regime) more seed electrons are initiated by multiphoton ionization, and the wavelength dependence of the threshold of optical breakdown results from a combination of nanorod's optical properties and transitions in the order of multiphoton ionization. The findings of this study can guide the design of nanoparticle based optical breakdown applications. This analysis also deepens the understanding of nanoparticle-mediated laser induced breakdown for picosecond and femtosecond pulses at near infrared wavelengths. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. High power multiple wavelength diode laser stack for DPSSL application without temperature control

    Science.gov (United States)

    Hou, Dong; Yin, Xia; Wang, Jingwei; Chen, Shi; Zhan, Yun; Li, Xiaoning; Fan, Yingmin; Liu, Xingsheng

    2018-02-01

    High power diode laser stack is widely used in pumping solid-state laser for years. Normally an integrated temperature control module is required for stabilizing the output power of solid-state laser, as the output power of the solid-state laser highly depends on the emission wavelength and the wavelength shift of diode lasers according to the temperature changes. However the temperature control module is inconvenient for this application, due to its large dimension, high electric power consumption and extra adding a complicated controlling system. Furthermore, it takes dozens of seconds to stabilize the output power when the laser system is turned on. In this work, a compact hard soldered high power conduction cooled diode laser stack with multiple wavelengths is developed for stabilizing the output power of solid-state laser in a certain temperature range. The stack consists of 5 laser bars with the pitch of 0.43mm. The peak output power of each bar in the diode laser stack reaches as much as 557W and the combined lasing wavelength spectrum profile spans 15nm. The solidstate laser, structured with multiple wavelength diode laser stacks, allows the ambient temperature change of 65°C without suddenly degrading the optical performance.

  4. The Wavelength Dependence of the Lunar Phase Curve as Seen by the LRO LAMP

    Science.gov (United States)

    Liu, Y.; Retherford, K. D.; Greathouse, T. K.; Hendrix, A. R.; Mandt, K.; Gladstone, R.; Cahill, J. T.; Egan, A.; Kaufmann, D. E.; Grava, C.; Pryor, W. R.

    2016-12-01

    The Lunar Reconnaissance Orbiter (LRO) Lyman Alpha Mapping Project (LAMP) provides global coverage of both nightside and dayside of the Moon in the far ultraviolet (FUV) wavelengths. The nightside observations use roughly uniform diffuse illumination sources from interplanetary medium Lyman-α sky glow and UV-bright stars so that traditional photometric corrections do not apply. In contrast, the dayside observations use sunlight as its illumination source where bidirectional reflectance is measured. The bidirectional reflectance is dependent on the incident, emission, and phase angles as well as the soil properties. Thus the comparisons of dayside mapping and nightside mapping techniques offer a method for cross-comparing the photometric correction factors because the observations are made under different lighting and viewing conditions. Specifically, the nightside data well constrain the single-scattering coefficient. We'll discuss the wavelength dependence of the lunar phase curve as seen by the LAMP instrument in dayside data. Our preliminary results indicate that the reflectance in the FUV wavelengths decreases with the increasing phase angles from 0° to 90°, similar to the phase curve in the UV-visible wavelengths as studied by Hapke et al. (2012) using LRO wide angle camera (WAC) data, among other visible-wavelength lunar studies. Particularly, we'll report how coherent backscattering and shadow hiding contribute to the opposition surge, given the fact that the albedo at FUV wavelengths is extremely low and thus multiple scattering is significantly less important. Finally, we'll report the derived Hapke parameters at FUV wavelengths for our study areas.

  5. The impact of positron emission tomography on primary tumour delineation and dosimetric outcome in intensity modulated radiotherapy of early T-stage nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Wu, Vincent W. C.; Leung, Wan-shun; Wong, Kwun-lam; Chan, Ying-kit; Law, Wing-lam; Leung, Wing-kwan; Yu, Yat-long

    2016-01-01

    In intensity modulated radiotherapy (IMRT) of nasopharyngeal carcinoma (NPC), accurate delineation of the gross tumour volume (GTV) is important. Image registration of CT and MRI has been routinely used in treatment planning. With recent development of positron emission tomography (PET), the aims of this study were to evaluate the impact of PET on GTV delineation and dosimetric outcome in IMRT of early stage NPC patients. Twenty NPC patients with T1 or T2 disease treated by IMRT were recruited. For each patient, 2 sets of NP GTVs were delineated separately, in which one set was performed using CT and MRI registration only (GTV CM ), while the other set was carried out using PET, CT and MRI information (GTV CMP ). A 9-field IMRT plan was computed based on the target volumes generated from CT and MRI (PTV CM ). To assess the geometric difference between the GTV CM and GTV CMP , GTV volumes and DICE similarity coefficient (DSC), which measured the geometrical similarity between the two GTVs, were recorded. To evaluate the dosimetric impact, the D max , D min , D mean and D 95 of PTVs were obtained from their dose volume histograms generated by the treatment planning system. The overall mean volume of GTV CMP was greater than GTV CM by 4.4 %, in which GTV CMP was slightly greater in the T1 group but lower in the T2 group. The mean DSC of the whole group was 0.79 ± 0.05. Similar mean DSC values were also obtained from the T1 and T2 groups separately. The dosimetric parameters of PTV CM fulfilled the planning requirements. When applying this plan to the PTV CMP , the average D min (56.9 Gy) and D 95 (68.6 Gy) of PTV CMP failed to meet the dose requirements and demonstrated significant differences from the PTV CM (p = 0.001 and 0.016 respectively), whereas the doses to GTV CMP did not show significant difference with the GTV CM . In IMRT of early stage NPC, PET was an important imaging modality in radiotherapy planning so as to avoid underdosing the PTV, although its

  6. The impact of positron emission tomography on primary tumour delineation and dosimetric outcome in intensity modulated radiotherapy of early T-stage nasopharyngeal carcinoma.

    Science.gov (United States)

    Wu, Vincent W C; Leung, Wan-Shun; Wong, Kwun-Lam; Chan, Ying-Kit; Law, Wing-Lam; Leung, Wing-Kwan; Yu, Yat-Long

    2016-08-24

    In intensity modulated radiotherapy (IMRT) of nasopharyngeal carcinoma (NPC), accurate delineation of the gross tumour volume (GTV) is important. Image registration of CT and MRI has been routinely used in treatment planning. With recent development of positron emission tomography (PET), the aims of this study were to evaluate the impact of PET on GTV delineation and dosimetric outcome in IMRT of early stage NPC patients. Twenty NPC patients with T1 or T2 disease treated by IMRT were recruited. For each patient, 2 sets of NP GTVs were delineated separately, in which one set was performed using CT and MRI registration only (GTVCM), while the other set was carried out using PET, CT and MRI information (GTVCMP). A 9-field IMRT plan was computed based on the target volumes generated from CT and MRI (PTVCM). To assess the geometric difference between the GTVCM and GTVCMP, GTV volumes and DICE similarity coefficient (DSC), which measured the geometrical similarity between the two GTVs, were recorded. To evaluate the dosimetric impact, the Dmax, Dmin, Dmean and D95 of PTVs were obtained from their dose volume histograms generated by the treatment planning system. The overall mean volume of GTVCMP was greater than GTVCM by 4.4 %, in which GTVCMP was slightly greater in the T1 group but lower in the T2 group. The mean DSC of the whole group was 0.79 ± 0.05. Similar mean DSC values were also obtained from the T1 and T2 groups separately. The dosimetric parameters of PTVCM fulfilled the planning requirements. When applying this plan to the PTVCMP, the average Dmin (56.9 Gy) and D95 (68.6 Gy) of PTVCMP failed to meet the dose requirements and demonstrated significant differences from the PTVCM (p = 0.001 and 0.016 respectively), whereas the doses to GTVCMP did not show significant difference with the GTVCM. In IMRT of early stage NPC, PET was an important imaging modality in radiotherapy planning so as to avoid underdosing the PTV, although its effect on GTV

  7. Biophotonic markers of malignancy: Discriminating cancers using wavelength-specific biophotons

    Directory of Open Access Journals (Sweden)

    Nirosha J. Murugan

    2018-03-01

    Full Text Available Early detection is a critically important factor when successfully diagnosing and treating cancer. Whereas contemporary molecular techniques are capable of identifying biomarkers associated with cancer, surgical interventions are required to biopsy tissue. The common imaging alternative, positron-emission tomography (PET, involves the use of nuclear material which poses some risks. Novel, non-invasive techniques to assess the degree to which tissues express malignant properties are now needed. Recent developments in biophoton research have made it possible to discriminate cancerous cells from normal cells both in vitro and in vivo. The current study expands upon a growing body of literature where we classified and characterized malignant and non-malignant cell types according to their biophotonic activity. Using wavelength-exclusion filters, we demonstrate that ratios between infrared and ultraviolet photon emissions differentiate cancer and non-cancer cell types. Further, we identified photon sources associated with three filters (420-nm, 620-nm., and 950-nm which classified cancer and non-cancer cell types. The temporal increases in biophoton emission within these wavelength bandwidths is shown to be coupled with intrisitic biomolecular events using Cosic's resonant recognition model. Together, the findings suggest that the use of wavelength-exclusion filters in biophotonic measurement can be employed to detect cancer in vitro.

  8. Influence of ns-laser wavelength in laser-induced breakdown spectroscopy for discrimination of painting techniques

    Science.gov (United States)

    Bai, Xueshi; Syvilay, Delphine; Wilkie-Chancellier, Nicolas; Texier, Annick; Martinez, Loic; Serfaty, Stéphane; Martos-Levif, Dominique; Detalle, Vincent

    2017-08-01

    The influence of ns-laser wavelength to discriminate ancient painting techniques such as are fresco, casein, animal glue, egg yolk and oil was investigated in this work. This study was carried out with a single shot laser on samples covered by a layer made of a mixture of the cinnabar pigment and different binders. Three wavelengths based on Nd: YAG laser were investigated (1064, 532 and 266 nm). The plasma is controlled at the same electron temperature after an adjustment of pulse energy for these three wavelengths on a fresco sample without organic binder. This approach allows to eliminate the effects of laser pulse energy and the material laser absorption. Afterwards, the emission spectra were compared to separate different techniques. The organic binding media has been separated based on the relative emission intensity of the present CN or C2 rovibrational emissions. In order to test the capability of separating or identifying, the chemometric approach (PCA) was applied to the different matrix. The different solutions in term of wavelength range to optimise the identification was investigated. We focused on the evaluation for the laser wavelength to insure a better separation. The different capacity was interpreted by differentiating the binders by the altered interaction mechanisms between the laser photon and the binders. Also, the electron temperature in the plasma was estimated, which provided the evidences to our findings.

  9. A radiation research apparatus sensitive to wavelength

    International Nuclear Information System (INIS)

    1980-01-01

    The apparatus described is equipped with a radiation source with a tuning device for the generation of X radiation of at least two different wavelength spectra. The detector with ionisation chamber is able to discriminate between these spectra. This is done with the aid of an auxillary electrode between the entrance window and a high voltage electrode. With a lower source of voltage this electrode has a potential equal to the high voltage electrode potential and with a higher voltage source it has a potential equal to the signal electrode potential. (Th.P.)

  10. Wavelength-agnostic WDM-PON System

    DEFF Research Database (Denmark)

    Wagner, Christoph; Eiselt, Michael; Zou, S.

    2016-01-01

    on the standardization status of this lowcost system in the new ITU-T G.metro draft recommendation, in the context of autonomous tuning. We also discuss some low-effort implementations of the pilot-tone labels and investigate the impact of these labels on the transmission channels.......Next-generation WDM-PON solutions for metro and access systems will take advantage of remotely controlled wavelength-tunable ONUs to keep system costs as low as possible. For such a purpose, each ONU signal can be labeled by a pilot tone modulated onto the optical data stream. We report...

  11. Sub-wavelength imaging at radio frequency

    International Nuclear Information System (INIS)

    Wiltshire, M C K; Pendry, J B; Hajnal, J V

    2006-01-01

    A slab of material with a negative permeability can act as a super-lens for magnetic fields and generate images with a sub-wavelength resolution. We have constructed an effective medium using a metamaterial with negative permeability in the region of 24 MHz, and used this to form images in free space of radio frequency magnetic sources. Measurements of these images show that a resolution of approximately λ/64 has been achieved, consistent with both analytical and numerical predictions. (letter to the editor)

  12. Gold Photoluminescence: Wavelength and Polarization Engineering

    DEFF Research Database (Denmark)

    Andersen, Sebastian Kim Hjælm; Pors, Anders Lambertus; Bozhevolnyi, Sergey I.

    2015-01-01

    We demonstrate engineering of the spectral content and polarization of photoluminescence (PL) from arrayed gold nanoparticles atop a subwavelength-thin dielectric spacer and optically-thick gold film, a configuration that supports gap-surface plasmon resonances (GSPRs). Choice of shapes...... and dimensions of gold nanoparticles influences the GSPR wavelength and polarization characteristics, thereby allowing us to enhance and spectrally mold the plasmon-assisted PL while simultaneously controlling its polarization. In order to understand the underlying physics behind the plasmon-enhanced PL, we...

  13. Wavelength converter placement in optical networks with dynamic traffic

    DEFF Research Database (Denmark)

    Buron, Jakob Due; Ruepp, Sarah Renée; Wessing, Henrik

    2008-01-01

    We evaluate the connection provisioning performance of GMPLS-controlled wavelength routed networks under dynamic traffic load and using three different wavelength converter placement heuristics. Results show that a simple uniform placement heuristic matches the performance of complex heuristics...

  14. Dynamic segment shared protection for multicast traffic in meshed wavelength-division-multiplexing optical networks

    Science.gov (United States)

    Liao, Luhua; Li, Lemin; Wang, Sheng

    2006-12-01

    We investigate the protection approach for dynamic multicast traffic under shared risk link group (SRLG) constraints in meshed wavelength-division-multiplexing optical networks. We present a shared protection algorithm called dynamic segment shared protection for multicast traffic (DSSPM), which can dynamically adjust the link cost according to the current network state and can establish a primary light-tree as well as corresponding SRLG-disjoint backup segments for a dependable multicast connection. A backup segment can efficiently share the wavelength capacity of its working tree and the common resources of other backup segments based on SRLG-disjoint constraints. The simulation results show that DSSPM not only can protect the multicast sessions against a single-SRLG breakdown, but can make better use of the wavelength resources and also lower the network blocking probability.

  15. Passively synchronized dual-wavelength Q-switched lasers

    DEFF Research Database (Denmark)

    Janousek, Jiri; Tidemand-Lichtenberg, Peter; Mortensen, Jesper Liltorp

    We present a simple and efficient way of generating synchronized Q-switched pulses at wavelengths hundreds of nanometers apart. This principle can result in new pulsed all-solid-state light sources at new wavelengths based on SFG.......We present a simple and efficient way of generating synchronized Q-switched pulses at wavelengths hundreds of nanometers apart. This principle can result in new pulsed all-solid-state light sources at new wavelengths based on SFG....

  16. Meter-wavelength VLBI. III. Pulsars

    International Nuclear Information System (INIS)

    Vandenberg, N.R.; Clark, T.A.; Clark, W.C.; Erickson, W.C.; Resch, G.M.; Broderick, J.J.

    1976-01-01

    The results and analysis of observations of pulsars, especially the Crab Nebula pulsar, taken during a series of meter-wavelength very long baseline interferometry (VLBI) experiments are discussed. Based on a crude 144 MHz visibility curve which is consistent with a Gaussian brightness distribution, the measured visibilities at 196, 111, and 74 MHz were interpreted to yield apparent angular diameters (at half-power) of 0 .03 +- 0 .01, 0 .07 +- 0 .01, and 0 .18 +- 0 .01, respectively. These sizes scale approximately as wavelength-squared, and the 74 MHz size agrees with recent observations using interplanetary scintillation techniques.The VLBI-measured total flux densities lie on the extrapolation from higher frequencies of the pulsing flux densities. Variations in the total flux density up to 25 percent were observed. A lack of fine structure other than the pulsar in the nebula is indicated by our simple visibility curves. The pulse shapes observed with the interferometer are similar to single-dish measurements at 196 MHz but reveal a steady, nonpulsing component at 111 MHz. The ratio of pulsing to total power was approximately equal to one-half but varied with time. No pulsing power was detected at 74 MHz. It was found that four strong, low-dispersion pulsars were only slightly resolved

  17. Long-wavelength microinstabilities in toroidal plasmas

    International Nuclear Information System (INIS)

    Tang, W.W.; Rewoldt, G.

    1993-01-01

    Realistic kinetic toroidal eigenmode calculations have been carried out to support a proper assessment of the influence of long-wavelength microturbulence on transport in tokamak plasmas. In order to efficiently evaluate large-scale kinetic behavior extending over many rational surfaces, significant improvements have been made to a toroidal finite element code used to analyze the fully two-dimensional (r,θ) mode structures of trapped-ion and toroidal ion temperature gradient (ITG) instabilities. It is found that even at very long wavelengths, these eigenmodes exhibit a strong ballooning character with the associated radial structure relatively insensitive to ion Landau damping at the rational surfaces. In contrast to the long-accepted picture that the radial extent of trapped-ion instabilities is characterized by the ion-gyroradius-scale associated with strong localization between adjacent rational surfaces, present results demonstrate that under realistic conditions, the actual scale is governed by the large-scale variations in the equilibrium gradients. Applications to recent measurements of fluctuation properties in TFTR L-mode plasmas indicate that the theoretical trends appear consistent with spectral characteristics as well as rough heuristic estimates of the transport level. Benchmarking calculations in support of the development of a three-dimensional toroidal gyrokinetic code indicate reasonable agreement with respect to both the properties of the eigenfunctions and the magnitude of the eigenvalues during the linear phase of the simulations of toroidal ITG instabilities

  18. Coherence techniques at extreme ultraviolet wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chang [Univ. of California, Berkeley, CA (United States)

    2002-01-01

    The renaissance of Extreme Ultraviolet (EUV) and soft x-ray (SXR) optics in recent years is mainly driven by the desire of printing and observing ever smaller features, as in lithography and microscopy. This attribute is complemented by the unique opportunity for element specific identification presented by the large number of atomic resonances, essentially for all materials in this range of photon energies. Together, these have driven the need for new short-wavelength radiation sources (e.g. third generation synchrotron radiation facilities), and novel optical components, that in turn permit new research in areas that have not yet been fully explored. This dissertation is directed towards advancing this new field by contributing to the characterization of spatial coherence properties of undulator radiation and, for the first time, introducing Fourier optical elements to this short-wavelength spectral region. The first experiment in this dissertation uses the Thompson-Wolf two-pinhole method to characterize the spatial coherence properties of the undulator radiation at Beamline 12 of the Advanced Light Source. High spatial coherence EUV radiation is demonstrated with appropriate spatial filtering. The effects of small vertical source size and beamline apertures are observed. The difference in the measured horizontal and vertical coherence profile evokes further theoretical studies on coherence propagation of an EUV undulator beamline. A numerical simulation based on the Huygens-Fresnel principle is performed.

  19. Artificial light pollution: Shifting spectral wavelengths to mitigate physiological and health consequences in a nocturnal marsupial mammal.

    Science.gov (United States)

    Dimovski, Alicia M; Robert, Kylie A

    2018-05-02

    The focus of sustainable lighting tends to be on reduced CO 2 emissions and cost savings, but not on the wider environmental effects. Ironically, the introduction of energy-efficient lighting, such as light emitting diodes (LEDs), may be having a great impact on the health of wildlife. These white LEDs are generated with a high content of short-wavelength 'blue' light. While light of any kind can suppress melatonin and the physiological processes it regulates, these short wavelengths are potent suppressors of melatonin. Here, we manipulated the spectral composition of LED lights and tested their capacity to mitigate the physiological and health consequences associated with their use. We experimentally investigated the impact of white LEDs (peak wavelength 448 nm; mean irradiance 2.87 W/m 2 ), long-wavelength shifted amber LEDs (peak wavelength 605 nm; mean irradiance 2.00 W/m 2 ), and no lighting (irradiance from sky glow light treatments. White LED exposed wallabies had significantly suppressed nocturnal melatonin compared to no light and amber LED exposed wallabies, while there was no difference in lipid peroxidation. Antioxidant capacity declined from baseline to week 10 under all treatments. These results provide further evidence that short-wavelength light at night is a potent suppressor of nocturnal melatonin. Importantly, we also illustrate that shifting the spectral output to longer wavelengths could mitigate these negative physiological impacts. © 2018 Wiley Periodicals, Inc.

  20. WDM cross-connect cascade based on all-optical wavelength converters for routing and wavelength slot interchanging using a reduced number of internal wavelengths

    DEFF Research Database (Denmark)

    Pedersen, Rune Johan Skullerud; Mikkelsen, Benny; Jørgensen, Bo Foged

    1998-01-01

    interchanging can be used to create a robust and nonblocking OXC. However, for an OXC with n fiber inlets each carrying m wavelengths the OXC requires n×m internal wavelengths, which constrains the size of the cross-connect. In this paper we therefore propose and demonstrate an architecture that uses a reduced......Optical transport layers need rearrangeable wavelength-division multiplexing optical cross-connects (OXCs) to increase the capacity and flexibility of the network. It has previously been shown that a cross-connect based on all-optical wavelength converters for routing as well as wavelength slot...... set of internal wavelengths without sacrificing cross-connecting capabilities. By inserting a partly equipped OXC with the new architecture in a 10-Gbit/s re-circulating loop setup we demonstrate the possibility of cascading up to ten OXCs. Furthermore, we investigate the regenerating effect...

  1. Heterodyne spatial interferometry of circumstellar dust shells at a wavelength of 11 microns

    International Nuclear Information System (INIS)

    Sutton, E.C.

    1979-01-01

    The spatial distribution of the 11 micron thermal emission from circumstellar dust envelopes has been studied using an infrared heterodyne interferometer. Circumstellar dust envelopes often exist around cool, late-type stars. These envelopes radiate strongly at 11 microns, particularly if they are composed of silicate grains, which have a strong emission feature near this wavelength. By measuring the spatial distribution of this dust emission it is possible to probe the temperatures and densities of the circumstellar material and thereby to gain an understanding of the structures of circumstellar envelopes. Among the sources which have been observed with this interferometer are α Orionis, o Ceti, VY Canis Majoris, and IRC + 10216. The 11 micron brightness distributions of these objects all have spatially extended dust-emission components which are resolved in these measurements. The dust envelopes of α Orionis and o Ceti are optically thin, having optical depths at 11 microns of 0.02 and 0.04, respectively. In addition, variations are seen in the 11 micron brightness distribution of o Ceti which correlate with the stellar variability. These variations primarily represent changes in the relative amount of spatially compact photospheric emission and spatially extended dust emission. The source VY Canis Majoris, on the other had, has a dust envelope which is optically thick at 11 microns. The dust envelope of IRC + 10216, although optically thick at visible wavelengths, does not seem to be optically thick at 11 microns since there is a spatially compact component of the 11 micron brightness distribution which presumably represents emission from the central star

  2. Investigation of concept of efficient short wavelength laser. Final technical report, April 1, 1977-July 31, 1979

    International Nuclear Information System (INIS)

    Piper, L.G.; Krech, R.H.; Pugh, E.; Taylor, R.L.

    1979-01-01

    The feasibility of producing an efficient, short wavelength, storage laser for ICF driven applications by making use of certain state-specific reactions of exoergic azide compounds has been investigated. The ultraviolet (approx. 300 nm) photolysis of gaseous ClN 3 produced prompt emission in the red, which was attributed to the efficient formation of ClN(b 1 Σ + ) with subsequent ClN(X reverse arrow b) fluorescence. Based on these results, a small-scale laser demonstration experiment was constructed using short duration Xe flash lamps as the photolytic source. The results of this latter experiment were negative. The most plausible explanation was that the flash lamps provided sufficient far-uv radiation to dissociate and/or ionize the ClN(b) produced in the primary photolytic step. In parallel, limited experiments were performed on the rapid pyrolysis of a solid, ionic azide, NaN 3 , to produce gaseous N 3 radicals and subsequent production of triplet N 2 molecules

  3. Dynamic Sensor Interrogation Using Wavelength-Swept Laser with a Polygon-Scanner-Based Wavelength Filter

    Science.gov (United States)

    Kwon, Yong Seok; Ko, Myeong Ock; Jung, Mi Sun; Park, Ik Gon; Kim, Namje; Han, Sang-Pil; Ryu, Han-Cheol; Park, Kyung Hyun; Jeon, Min Yong

    2013-01-01

    We report a high-speed (∼2 kHz) dynamic multiplexed fiber Bragg grating (FBG) sensor interrogation using a wavelength-swept laser (WSL) with a polygon-scanner-based wavelength filter. The scanning frequency of the WSL is 18 kHz, and the 10 dB scanning bandwidth is more than 90 nm around a center wavelength of 1,540 nm. The output from the WSL is coupled into the multiplexed FBG array, which consists of five FBGs. The reflected Bragg wavelengths of the FBGs are 1,532.02 nm, 1,537.84 nm, 1,543.48 nm, 1,547.98 nm, and 1,553.06 nm, respectively. A dynamic periodic strain ranging from 500 Hz to 2 kHz is applied to one of the multiplexed FBGs, which is fixed on the stage of the piezoelectric transducer stack. Good dynamic performance of the FBGs and recording of their fast Fourier transform spectra have been successfully achieved with a measuring speed of 18 kHz. The signal-to-noise ratio and the bandwidth over the whole frequency span are determined to be more than 30 dB and around 10 Hz, respectively. We successfully obtained a real-time measurement of the abrupt change of the periodic strain. The dynamic FBG sensor interrogation system can be read out with a WSL for high-speed and high-sensitivity real-time measurement. PMID:23899934

  4. MODELING MULTI-WAVELENGTH PULSE PROFILES OF THE MILLISECOND PULSAR PSR B1821–24

    Energy Technology Data Exchange (ETDEWEB)

    Du, Yuanjie; Shuai, Ping; Bei, Xiaomin; Chen, Shaolong; Fu, Linzhong; Huang, Liangwei; Lin, Qingqing; Meng, Jing; Wu, Yaojun; Zhang, Hengbin; Zhang, Qian; Zhang, Xinyuan [Qian Xuesen Laboratory of Space Technology, NO. 104, Youyi Road, Haidian District, Beijing 100094 (China); Qiao, Guojun, E-mail: dyj@nao.cas.cn [School of Physics, Peking University, Beijing 100871 (China)

    2015-03-10

    PSR B1821–24 is a solitary millisecond pulsar that radiates multi-wavelength pulsed photons. It has complex radio, X-ray, and γ-ray pulse profiles with distinct peak phase separations that challenge the traditional caustic emission models. Using the single-pole annular gap model with a suitable magnetic inclination angle (α = 40°) and viewing angle (ζ = 75°), we managed to reproduce its pulse profiles of three wavebands. It is found that the middle radio peak originated from the core gap region at high altitudes, and the other two radio peaks originated from the annular gap region at relatively low altitudes. Two peaks of both X-ray and γ-ray wavebands basically originated from the annular gap region, while the γ-ray emission generated from the core gap region contributes somewhat to the first γ-ray peak. Precisely reproducing the multi-wavelength pulse profiles of PSR B1821–24 enables us to understand emission regions of distinct wavebands and justify pulsar emission models.

  5. Temperature Characteristics of Monolithically Integrated Wavelength-Selectable Light Sources

    International Nuclear Information System (INIS)

    Han Liang-Shun; Zhu Hong-Liang; Zhang Can; Ma Li; Liang Song; Wang Wei

    2013-01-01

    The temperature characteristics of monolithically integrated wavelength-selectable light sources are experimentally investigated. The wavelength-selectable light sources consist of four distributed feedback (DFB) lasers, a multimode interferometer coupler, and a semiconductor optical amplifier. The oscillating wavelength of the DFB laser could be modulated by adjusting the device operating temperature. A wavelength range covering over 8.0nm is obtained with stable single-mode operation by selecting the appropriate laser and chip temperature. The thermal crosstalk caused by the lateral heat spreading between lasers operating simultaneously is evaluated by oscillating-wavelength shift. The thermal crosstalk approximately decreases exponentially as the increasing distance between lasers

  6. Analysis of subsystems in wavelength-division-multiplexing networks

    DEFF Research Database (Denmark)

    Liu, Fenghai

    2001-01-01

    Wavelength division multiplexing (WDM) technology together with optical amplification has created a new era for optical communication. Transmission capacity is greatly increased by adding more and more wavelength channels into a single fiber, as well as by increasing the line rate of each channel...... in semiconductor optical amplifiers (SOAs), and dispersion managed fiber sections. New subsystems are also proposed in the thesis: a modular 2×2 multiwavelength cross-connect using wavelength switching blocks, a wavelength converter based on cross phase modulation in a semiconductor modulator, a wavelength...

  7. Comparison of primary tumour volumes delineated on four-dimensional computed tomography maximum intensity projection and 18F-fluorodeoxyglucose positron emission tomography computed tomography images of non-small cell lung cancer

    International Nuclear Information System (INIS)

    Duan, Yili; Li, Jianbin; Zhang, Yingjie; Wang, Wei; Fan, Tingyong; Shao, Qian; Xu, Min; Guo, Yanluan; Sun, Xiaorong; Shang, Dongping

    2015-01-01

    The study aims to compare the positional and volumetric differences of tumour volumes based on the maximum intensity projection (MIP) of four-dimensional CT (4DCT) and 18 F-fluorodexyglucose ( 18 F-FDG) positron emission tomography CT (PET/CT) images for the primary tumour of non-small cell lung cancer (NSCLC). Ten patients with NSCLC underwent 4DCT and 18 F-FDG PET/CT scans of the thorax on the same day. Internal gross target volumes (IGTVs) of the primary tumours were contoured on the MIP images of 4DCT to generate IGTV MIP . Gross target volumes (GTVs) based on PET (GTV PET ) were determined with nine different threshold methods using the auto-contouring function. The differences in the volume, position, matching index (MI) and degree of inclusion (DI) of the GTV PET and IGTV MIP were investigated. In volume terms, GTV PET2.0 and GTV PET20% approximated closely to IGTV MIP with mean volume ratio of 0.93 ± 0.45 and 1.06 ± 0.43, respectively. The best MI was between IGTV MIP and GTV PET20% (0.45 ± 0.23). The best DI of IGTV MIP in GTV PET was IGTV MIP in GTV PET20% (0.61 ± 0.26). In 3D PET images, the GTVPET contoured by standardised uptake value (SUV) 2.0 or 20% of maximal SUV (SUV max ) approximate closely to the IGTV MIP in target size, while the spatial mismatch is apparent between them. Therefore, neither of them could replace IGTV MIP in spatial position and form. The advent of 4D PET/CT may improve the accuracy of contouring the perimeter for moving targets.

  8. Diagnostic Accuracy of 64Copper Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography for Primary Lymph Node Staging of Intermediate- to High-risk Prostate Cancer: Our Preliminary Experience.

    Science.gov (United States)

    Cantiello, Francesco; Gangemi, Vincenzo; Cascini, Giuseppe Lucio; Calabria, Ferdinando; Moschini, Marco; Ferro, Matteo; Musi, Gennaro; Butticè, Salvatore; Salonia, Andrea; Briganti, Alberto; Damiano, Rocco

    2017-08-01

    To assess the diagnostic accuracy of 64 Copper prostate-specific membrane antigen ( 64 Cu-PSMA) positron emission tomography/computed tomography (PET/CT) in the primary lymph node (LN) staging of a selected cohort of intermediate- to high-risk prostate cancer (PCa) patients. An observational prospective study was performed in 23 patients with intermediate- to high-risk PCa, who underwent 64 Cu-PSMA PET/CT for local and lymph nodal staging before laparoscopic radical prostatectomy with an extended pelvic LN dissection. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for LN status of 64 Cu-PSMA PET/CT were calculated using the final pathological findings as reference. Furthermore, we evaluated the correlation of intraprostatic tumor extent and grading with 64 Cu-PSMA intraprostatic distribution. Pathological analysis of LN involvement in 413 LNs harvested from our study cohort identified a total of 22 LN metastases in 8 (5%) of the 23 (35%) PCa patients. Imaging-based LN staging in a per-patient analysis showed that 64 Cu-PSMA PET/CT was positive in 7 of 8 LN-positive patients (22%) with a sensitivity of 87.5%, specificity of 100%, PPV of 100%, and NPV of 93.7%, considering the maximum standardized uptake value (SUV max ) at 4 hours as our reference. Receiver operating characteristic curve was characterized by an area under the curve of 0.938. A significant positive association was observed between SUV max at 4 hours with Gleason score, index, and cumulative tumor volume. In our intermediate- to high-risk PCa patients study cohort, we showed the high diagnostic accuracy of 64 Cu-PSMA PET/CT for primary LN staging before radical prostatectomy. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Spin and wavelength multiplexed nonlinear metasurface holography

    Science.gov (United States)

    Ye, Weimin; Zeuner, Franziska; Li, Xin; Reineke, Bernhard; He, Shan; Qiu, Cheng-Wei; Liu, Juan; Wang, Yongtian; Zhang, Shuang; Zentgraf, Thomas

    2016-06-01

    Metasurfaces, as the ultrathin version of metamaterials, have caught growing attention due to their superior capability in controlling the phase, amplitude and polarization states of light. Among various types of metasurfaces, geometric metasurface that encodes a geometric or Pancharatnam-Berry phase into the orientation angle of the constituent meta-atoms has shown great potential in controlling light in both linear and nonlinear optical regimes. The robust and dispersionless nature of the geometric phase simplifies the wave manipulation tremendously. Benefitting from the continuous phase control, metasurface holography has exhibited advantages over conventional depth controlled holography with discretized phase levels. Here we report on spin and wavelength multiplexed nonlinear metasurface holography, which allows construction of multiple target holographic images carried independently by the fundamental and harmonic generation waves of different spins. The nonlinear holograms provide independent, nondispersive and crosstalk-free post-selective channels for holographic multiplexing and multidimensional optical data storages, anti-counterfeiting, and optical encryption.

  10. Aligning of single and multiple wavelength chromatographic

    DEFF Research Database (Denmark)

    Nielsen, Niels-Peter Vest; Carstensen, Jens Michael; Smedsgaard, Jørn

    1998-01-01

    optimised warping (COW) using two input parameters which can be estimated from the observed peak width. COW is demonstrated on constructed single trace chromatograms and on single and multiple wavelength chromatograms obtained from HPLC diode detection analyses of fungal extractsA copy of the C program......The use of chemometric data processing is becoming an important part of modern chromatography. Most chemometric analyses are performed on reduced data sets using areas of selected peaks detected in the chromatograms, which means a loss of data and introduces the problem of extracting peak data from...... to utilise the entire data matrix or rely on peak detection, thus having the same limitations as the commonly used chemometric procedures. The method presented uses the entire chromatographic data matrices and does not require any preprocessing e.g., peak detection. It relies on piecewise linear correlation...

  11. Single wavelength standard wiggler for PEP

    International Nuclear Information System (INIS)

    Brunk, W.; Fischer, G.; Spencer, J.

    1979-03-01

    A 1lambda planar wiggler has been designed that will be used for the initial operation of the 4 to 18 GeV storage ring PEP. Three of these wigglers will be installed symmetrically around the ring at 120 0 intervals in three of six available 5 m straight sections with the purpose of providing: (1) beam size control to obtain better luminosities below 15 GeV, and (2) decreased damping times to obtain better injection rates at lower energies. Design goals are discussed and a description of the final system including cost estimates is given. Expected results and usage in PEP are discussed. Some possibilities for production of synchrotron radiation and beam monitoring with shorter wavelength, multiple-period wigglers at PEP energies are also discussed. Comparison to a wiggler now operating in SPEAR is given

  12. Long-wavelength microinstabilities in toroidal plasmas

    International Nuclear Information System (INIS)

    Tang, W.M.; Rewoldt, G.

    1993-01-01

    Realistic kinetic toroidal eigenmode calculations have been carried out to support a proper assessment of the influence of long-wavelength microturbulence on transport in tokamak plasmas. In order to efficiently evaluate large-scale kinetic behavior extending over many rational surfaces, significant improvements have been made to a toroidal finite element code used to analyze the fully two-dimensional (r,θ) mode structures of trapped-ion and toroidal ion temperature gradient (ITG) instabilities. It is found that even at very long wavelengths, these eigenmodes exhibit a strong ballooning character with the associated radial structure relatively insensitive to ion Landau damping at the rational surfaces. In contrast to the long-accepted picture that the radial extent of trapped-ion instabilities is characterized by the ion-gyroradius-scale associated with strong localization between adjacent rational surfaces, present results demonstrate that under realistic conditions, the actual scale is governed by the large-scale variations in the equilibrium gradients. Applications to recent measurements of fluctuation properties in Tokamak Fusion Test Reactor (TFTR) [Plasma Phys. Controlled Nucl. Fusion Res. (International Atomic Energy Agency, Vienna, 1985), Vol. 1, p. 29] L-mode plasmas indicate that the theoretical trends appear consistent with spectral characteristics as well as rough heuristic estimates of the transport level. Benchmarking calculations in support of the development of a three-dimensional toroidal gyrokinetic code indicate reasonable agreement with respect to both the properties of the eigenfunctions and the magnitude of the eigenvalues during the linear phase of the simulations of toroidal ITG instabilities

  13. Outsourcing CO2 Emissions

    Science.gov (United States)

    Davis, S. J.; Caldeira, K. G.

    2009-12-01

    CO2 emissions from the burning of fossil fuels are the primary cause of global warming. Much attention has been focused on the CO2 directly emitted by each country, but relatively little attention has been paid to the amount of emissions associated with consumption of goods and services in each country. This consumption-based emissions inventory differs from the production-based inventory because of imports and exports of goods and services that, either directly or indirectly, involved CO2 emissions. Using the latest available data and reasonable assumptions regarding trans-shipment of embodied carbon through third-party countries, we developed a global consumption-based CO2 emissions inventory and have calculated associated consumption-based energy and carbon intensities. We find that, in 2004, 24% of CO2 emissions are effectively outsourced to other countries, with much of the developed world outsourcing CO2 emissions to emerging markets, principally China. Some wealthy countries, including Switzerland and Sweden, outsource over half of their consumption-based emissions, with many northern Europeans outsourcing more than three tons of emissions per person per year. The United States is both a big importer and exporter of emissions embodied in trade, outsourcing >2.6 tons of CO2 per person and at the same time as >2.0 tons of CO2 per person are outsourced to the United States. These large flows indicate that CO2 emissions embodied in trade must be taken into consideration when considering responsibility for increasing atmospheric greenhouse gas concentrations.

  14. Wavelength-Dependent Extinction and Grain Sizes in "Dippers"

    Science.gov (United States)

    Sitko, Michael; Russell, Ray W.; Long, Zachary; Bayyari, Ammar; Assani, Korash; Grady, Carol; Lisse, Carey Michael; Marengo, Massimo; Wisniewski, John

    2018-01-01

    We have examined inter-night variability of K2-discovered "Dippers" that are not close to being viewed edge-on (as determined from previously-reported ALMA images) using the SpeX spectrograph on NASA's Infrared Telescope facility (IRTF). The three objects observed were EPIC 203850058, EPIC 205151387, and EPIC 204638512 ( = 2MASS J16042165-2130284). Using the ratio of the fluxes from 0.7-2.4 microns between two successive nights, we find that in at least two cases, the extinction increased toward shorter wavelengths. In the case of EPIC 204638512, we find that the properties of the dust differ from that seen in the diffuse interstellar medium and denser molecular clouds. However, the grain properties needed to explain the extinction does resemble those used to model the disks of many young stellar objects. The best fit to the data on EPIC 204638512 includes grains at least 500 microns in size, but lacks grains smaller than 0.25 microns. Since EPIC 204638512 is seen nearly face-on, it is possible the grains are entrained in an accretion flow that preferentially destroys the smallest grains. However, we have no indication of significant gas accretion onto the star in the form of emission lines observed in young low-mass stars. But the He I line at 1.083 microns was seen to change from night to night, and showed a P Cygni profile on one night, suggesting the gas might be outflowing from regions near the star.

  15. Planck 2013 results. XIV. Zodiacal emission

    DEFF Research Database (Denmark)

    Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.

    2013-01-01

    , three asteroidal dust bands, a circumsolar ring, and an Earth-trailing feature. The emissivity of the diuse cloud decreases with increasing wavelength, as expected from earlier analyses. The emissivities of the dust bands, however, decrease less rapidly, indicating that the properties of the grains......The Planck satellite provides a set of all-sky maps at nine frequencies from 30 GHz to 857 GHz. Planets, minor bodies, and diuse interplanetary dust emission (IPD) are all observed. The IPD can be separated from Galactic and other emissions because Planck views a given point on the celestial sphere...

  16. Emissivity measurements on aeronautical alloys

    International Nuclear Information System (INIS)

    Campo, L. del; Perez-Saez, R.B.; Gonzalez-Fernandez, L.; Esquisabel, X.; Fernandez, I.; Gonzalez-Martin, P.; Tello, M.J.

    2010-01-01

    The emissivity of three Ni and Co based aeronautical alloys is analyzed in this paper. These alloys are employed in high temperature environments whenever good corrosion resistance, high temperature resistance and high strength are essential. Thus, apart from the aeronautical industry, these alloys are also used in other technological applications, as for example, aerospace, nuclear reactors, and tooling. The results in this paper extend the emissivity data for these alloys available in the literature. Emissivity dependence on the radiation wavelength (2-22 μm), sample temperature (200-650 o C) and emission angle (0-85 o ) has been investigated. In addition, the effect of surface finish and oxidation has also been taken into consideration. The data in this paper have several applications, as temperature measurement of a target by pyrometry, low observability of airplanes and thermal radiation heat transfer simulation in airplane nozzles or furnaces.

  17. Emissivity measurements on aeronautical alloys

    Energy Technology Data Exchange (ETDEWEB)

    Campo, L. del, E-mail: leire.del-campo@cnrs-orleans.f [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Perez-Saez, R.B., E-mail: raul.perez@ehu.e [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Instituto de Sintesis y Estudio de Materiales, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao (Spain); Gonzalez-Fernandez, L. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Esquisabel, X.; Fernandez, I. [Industria de Turbo Propulsores, S.A., Planta de Zamudio, Edificio 300, 48170 Zamudio, Bizkaia (Spain); Gonzalez-Martin, P. [Industria de Turbo Propulsores, S.A., Parque empresarial San Fernando, Avda. Castilla 2, 28830 San Fernando de Henares, Madrid (Spain); Tello, M.J. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Instituto de Sintesis y Estudio de Materiales, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao (Spain)

    2010-01-21

    The emissivity of three Ni and Co based aeronautical alloys is analyzed in this paper. These alloys are employed in high temperature environments whenever good corrosion resistance, high temperature resistance and high strength are essential. Thus, apart from the aeronautical industry, these alloys are also used in other technological applications, as for example, aerospace, nuclear reactors, and tooling. The results in this paper extend the emissivity data for these alloys available in the literature. Emissivity dependence on the radiation wavelength (2-22 {mu}m), sample temperature (200-650 {sup o}C) and emission angle (0-85{sup o}) has been investigated. In addition, the effect of surface finish and oxidation has also been taken into consideration. The data in this paper have several applications, as temperature measurement of a target by pyrometry, low observability of airplanes and thermal radiation heat transfer simulation in airplane nozzles or furnaces.

  18. Survey of the energy market in Germany in 2000. Primary energy consumption - carbon dioxide emissions - mineral oil - lignite - coal - natural gas - electricity - energy prices - import bill; Deutscher Energiemarkt 2000. Primaerenergie - Treibhausgas-Emissionen - Mineraloel - Braunkohle - Steinkohle - Erdgas - Elektrizitaet - Energiepreise - Importrechnung

    Energy Technology Data Exchange (ETDEWEB)

    Schiffer, H.W. [RWE Rheinbraun AG, Koeln (Germany)

    2001-03-01

    Primary energy consumption in Germany in 2000 amounted to 483.6m tonnes of coal equivalent and thus decreased by 0.2%, as compared to 1999. The comprehensive survey consists of tabulated data and explanatory comments relating to the developments linked to the various energy sources, change of energy mix, generation technologies and systems, demand factors and consumer behavior, carbon dioxide emissions, renewable energies and cogeneration and the government policies, imports and prices. (orig./CB) [German] Der Primaerenergieverbrauch in der Bundesrepublik Deutschland belief sich im Jahr 2000 auf 483,6 Millionen Tonnen Steinkohleneinheiten (Mio. t SKE), d.h. er war 0,2% niedriger als im Vorjahr. Hinsichtlich der Entwicklung in 2000 im Vergleich zu 1999 wurden u.a. folgende Tendenzen festgestellt: 1. Wandel im Energiemix. 2. Rueckgang der CO2-Emissionen, ausser im Verkehrssektor. 3. Gestiegenes Mineraloelaufkommen, aber veraenderte Zusammensetzung. 4. Anstieg bei Gewinnung und Einsatz von Braunkohle, Verringerung bei Steinkohle. Die Daten werden erlaeutert, wobei auch auf geaenderte rechtliche Rahmenbedingungen und die neuere Energiepolitik hingewiesen wird. (orig./CB)

  19. Nanoparticle discrimination based on wavelength and lifetime-multiplexed cathodoluminescence microscopy.

    Science.gov (United States)

    Garming, Mathijs W H; Weppelman, I Gerward C; de Boer, Pascal; Martínez, Felipe Perona; Schirhagl, Romana; Hoogenboom, Jacob P; Moerland, Robert J

    2017-08-31

    Nanomaterials can be identified in high-resolution electron microscopy images using spectrally-selective cathodoluminescence. Capabilities for multiplex detection can however be limited, e.g., due to spectral overlap or availability of filters. Also, the available photon flux may be limited due to degradation under electron irradiation. Here, we demonstrate single-pass cathodoluminescence-lifetime based discrimination of different nanoparticles, using a pulsed electron beam. We also show that cathodoluminescence lifetime is a robust parameter even when the nanoparticle cathodoluminescence intensity decays over an order of magnitude. We create lifetime maps, where the lifetime of the cathodoluminescence emission is correlated with the emission intensity and secondary-electron images. The consistency of lifetime-based discrimination is verified by also correlating the emission wavelength and the lifetime of nanoparticles. Our results show how cathodoluminescence lifetime provides an additional channel of information in electron microscopy.

  20. Design and implementation of a dual-wavelength intrinsic fluorescence camera system

    Science.gov (United States)

    Ortega-Martinez, Antonio; Musacchia, Joseph J.; Gutierrez-Herrera, Enoch; Wang, Ying; Franco, Walfre

    2017-03-01

    Intrinsic UV fluorescence imaging is a technique that permits the observation of spatial differences in emitted fluorescence. It relies on the fluorescence produced by the innate fluorophores in the sample, and thus can be used for marker-less in-vivo assessment of tissue. It has been studied as a tool for the study of the skin, specifically for the classification of lesions, the delimitation of lesion borders and the study of wound healing, among others. In its most basic setup, a sample is excited with a narrow-band UV light source and the resulting fluorescence is imaged with a UV sensitive camera filtered to the emission wavelength of interest. By carefully selecting the excitation/emission pair, we can observe changes in fluorescence associated with physiological processes. One of the main drawbacks of this simple setup is the inability to observe more than a single excitation/emission pair at the same time, as some phenomena are better studied when two or more different pairs are studied simultaneously. In this work, we describe the design and the hardware and software implementation of a dual wavelength portable UV fluorescence imaging system. Its main components are an UV camera, a dual wavelength UV LED illuminator (295 and 345 nm) and two different emission filters (345 and 390 nm) that can be swapped by a mechanical filter wheel. The system is operated using a laptop computer and custom software that performs basic pre-processing to improve the image. The system was designed to allow us to image fluorescent peaks of tryptophan and collagen cross links in order to study wound healing progression.

  1. Plasmonic distributed feedback lasers at telecommunications wavelengths.

    Science.gov (United States)

    Marell, Milan J H; Smalbrugge, Barry; Geluk, Erik Jan; van Veldhoven, Peter J; Barcones, Beatrix; Koopmans, Bert; Nötzel, Richard; Smit, Meint K; Hill, Martin T

    2011-08-01

    We investigate electrically pumped, distributed feedback (DFB) lasers, based on gap-plasmon mode metallic waveguides. The waveguides have nano-scale widths below the diffraction limit and incorporate vertical groove Bragg gratings. These metallic Bragg gratings provide a broad bandwidth stop band (~500 nm) with grating coupling coefficients of over 5000/cm. A strong suppression of spontaneous emission occurs in these Bragg grating cavities, over the stop band frequencies. This strong suppression manifests itself in our experimental results as a near absence of spontaneous emission and significantly reduced lasing thresholds when compared to similar length Fabry-Pérot waveguide cavities. Furthermore, the reduced threshold pumping requirements permits us to show strong line narrowing and super linear light current curves for these plasmon mode devices even at room temperature.

  2. Tunable multi-wavelength polymer laser based on a triangular-lattice photonic crystal structure

    International Nuclear Information System (INIS)

    Huang, Wenbin; Pu, Donglin; Qiao, Wen; Wan, Wenqiang; Liu, Yanhua; Ye, Yan; Wu, Shaolong; Chen, Linsen

    2016-01-01

    A continuously tunable multi-wavelength polymer laser based on a triangular-lattice photonic crystal cavity is demonstrated. The triangular-lattice resonator was initially fabricated through multiple interference exposure and was then replicated into a low refractive index polymer via UV-nanoimprinting. The blend of a blue-emitting conjugated polymer and a red-emitting one was used as the gain medium. Three periods in the scalene triangular-lattice structure yield stable tri-wavelength laser emission (625.5 nm, 617.4 nm and 614.3 nm) in six different directions. A uniformly aligned liquid crystal (LC) layer was incorporated into the cavity as the top cladding layer. Upon heating, the orientation of LC molecules and thus the effective refractive index of the lasing mode changes which continuously shifts the lasing wavelength. A maximum tuning range of 12.2 nm was observed for the lasing mode at 625.5 nm. This tunable tri-wavelength polymer laser is simple constructed and cost-effective. It may find application in the fields of biosensors and photonic integrated circuits. (paper)

  3. High-efficiency and low-loss gallium nitride dielectric metasurfaces for nanophotonics at visible wavelengths

    Science.gov (United States)

    Emani, Naresh Kumar; Khaidarov, Egor; Paniagua-Domínguez, Ramón; Fu, Yuan Hsing; Valuckas, Vytautas; Lu, Shunpeng; Zhang, Xueliang; Tan, Swee Tiam; Demir, Hilmi Volkan; Kuznetsov, Arseniy I.

    2017-11-01

    The dielectric nanophotonics research community is currently exploring transparent material platforms (e.g., TiO2, Si3N4, and GaP) to realize compact high efficiency optical devices at visible wavelengths. Efficient visible-light operation is key to integrating atomic quantum systems for future quantum computing. Gallium nitride (GaN), a III-V semiconductor which is highly transparent at visible wavelengths, is a promising material choice for active, nonlinear, and quantum nanophotonic applications. Here, we present the design and experimental realization of high efficiency beam deflecting and polarization beam splitting metasurfaces consisting of GaN nanostructures etched on the GaN epitaxial substrate itself. We demonstrate a polarization insensitive beam deflecting metasurface with 64% and 90% absolute and relative efficiencies. Further, a polarization beam splitter with an extinction ratio of 8.6/1 (6.2/1) and a transmission of 73% (67%) for p-polarization (s-polarization) is implemented to demonstrate the broad functionality that can be realized on this platform. The metasurfaces in our work exhibit a broadband response in the blue wavelength range of 430-470 nm. This nanophotonic platform of GaN shows the way to off- and on-chip nonlinear and quantum photonic devices working efficiently at blue emission wavelengths common to many atomic quantum emitters such as Ca+ and Sr+ ions.

  4. Multi-wavelength study of infrared galaxies

    International Nuclear Information System (INIS)

    Marcillac, Delphine

    2005-01-01

    This thesis deals with a panchromatic study of luminous infrared galaxies (LIRGs) detected at 15 microns by ISOCAM (camera aboard ISO) and at 24 microns by MIPS (camera aboard the recently launched Spitzer satellite). These galaxies are today considered to be the Rosetta Stone of galaxy evolution since they are found to be far more numerous at high redshift and it is thought that a large part of stars seen in the local universe are born in such phases. The first part of this thesis presents a new study dedicated to dust emission of distant LIRGs in the mid-infrared range. Their dust emission has been compared to those of a local sample of LIRGs in addition to the prediction of several spectral energy distributions (SEDs) built on data available in the local universe. It has been shown that distant and local LIRGs present similar mid infrared spectral energy distribution: similar PAH bumps are detected in both local and distant LIRGs, however distant LIRGs show evidence of a stronger silicate absorption at 10 microns associated silicate grains. It also shows that distant LIRG mid infrared emission can be used together with local SEDs in order to estimate the total infrared luminosity. The second part of this thesis is dedicated to the burst of star formation and to the recent star formation history of these galaxies, which is responsible for the dust emission. This study was done thanks to a combination of high resolution spectra (R=2000 in the rest frame) obtained at VLT/FORS2 and the stellar population synthesis models called GALAXEV (Bruzual and Charlot, 2003). It has been shown that the burst of star formation has a duration of about 0.1 Gyear. About 10 % of the stellar content is formed during this burst of star formation. (author) [fr

  5. Wavelength-stepped, actively mode-locked fiber laser based on wavelength-division-multiplexed optical delay lines

    Science.gov (United States)

    Lee, Eunjoo; Kim, Byoung Yoon

    2017-12-01

    We propose a new scheme for an actively mode-locked wavelength-swept fiber laser that produces a train of discretely wavelength-stepped pulses from a short fiber cavity. Pulses with different wavelengths are split and combined by standard wavelength division multiplexers with fiber delay lines. As a proof of concept, we demonstrate a laser using an erbium doped fiber amplifier and commercially available wavelength-division multiplexers with wavelength spacing of 0.8 nm. The results show simultaneous mode-locking at three different wavelengths. Laser output parameters in time domain, optical and radio frequency spectral domain, and the noise characteristics are presented. Suggestions for the improved design are discussed.

  6. Emission from power plants 1989-1998

    International Nuclear Information System (INIS)

    Anon.

    1999-01-01

    Emissions from power plants consist of several substances with different environmental effects. Most important is emission of CO 2 ,SO 2 and NO x . The actual emission of CO 2 declined from 33 million ton in 1997 to 29 million ton in 1998, while the corrected emission of CO 2 declined from 27 million ton to 26 million ton. The primary cause to the decline in the actual emission of CO 2 is the constant changing of the energy consumption from coal towards natural gas. The corrected emission of CO 2 increased a little from 1989 to 1991, but has declined since 1991. The actual emission of CO 2 has been more variable, which especially reflects the fluctuating import and export of electricity. The actual emission of SO 2 has in the period varied, but the tendency is declining emission of SO 2 . In the years 1991 and 1996 the actual emission of SO 2 increased, these being the years where the net export of electricity increased. The corrected emission of SO 2 has generally declined during the period. The actual emission of NO x has varied during the period, but the tendency is declining emission. Emission of NO x has been large this year with large electricity export. Correction the emission for net import and export of electricity the NO x emission has declined during 1989-1998. The corrected emission of NO x has declined 54 % during the period 1989-1998. The reason is primary the usage of low NO x burners. (EHS)

  7. Pulsar Emission: Is It All Relative?

    Science.gov (United States)

    Harding, Alice K.

    2004-01-01

    Thirty-five years after the discovery of pulsars, we still do not understand the fundamentals of their pulsed emission at any wavelength. The fact that even detailed pulse profiles cannot identlfy the origin of the emission in a magnetosphere that extends fiom the neutron star surface to plasma moving at relativistic speeds near the light cylinder compounds the problem. I will discuss the role of special and general relativistic effects on pulsar emission, fiom inertial frame-dragging near the stellar surface to aberration, time-of-flight and retardation of the magnetic field near the light cylinder. Understanding how these effects determine what we observe at different wavelengths is critical to unraveling the emission physics.

  8. Amenorrhea - primary

    Science.gov (United States)

    ... of periods - primary Images Primary amenorrhea Normal uterine anatomy (cut section) Absence of menstruation (amenorrhea) References Bulun SE. The physiology and pathology of the female reproductive axis. In: ...

  9. Emissions Trading

    NARCIS (Netherlands)

    Woerdman, Edwin; Backhaus, Juergen

    2014-01-01

    Emissions trading is a market-based instrument to achieve environmental targets in a cost-effective way by allowing legal entities to buy and sell emission rights. The current international dissemination and intended linking of emissions trading schemes underlines the growing relevance of this

  10. Optimal Fluorescence Waveband Determination for Detecting Defective Cherry Tomatoes Using a Fluorescence Excitation-Emission Matrix

    Directory of Open Access Journals (Sweden)

    In-Suck Baek

    2014-11-01

    Full Text Available A multi-spectral fluorescence imaging technique was used to detect defective cherry tomatoes. The fluorescence excitation and emission matrix was used to measure for defects, sound surface and stem areas to determine the optimal fluorescence excitation and emission wavelengths for discrimination. Two-way ANOVA revealed the optimal excitation wavelength for detecting defect areas was 410 nm. Principal component analysis (PCA was applied to the fluorescence emission spectra of all regions at 410 nm excitation to determine the emission wavelengths for defect detection. The major emission wavelengths were 688 nm and 506 nm for the detection. Fluorescence images combined with the determined emission wavebands demonstrated the feasibility of detecting defective cherry tomatoes with >98% accuracy. Multi-spectral fluorescence imaging has potential utility in non-destructive quality sorting of cherry tomatoes.

  11. Carbon emissions in China

    International Nuclear Information System (INIS)

    Liu, Zhu

    2016-01-01

    This study analyzes the spatial-temporal pattern and processes of China's energy-related carbon emissions. Based on extensive quantitative analysis, it outlines the character and trajectory of China's energy-related carbon emissions during the period 1995-2010, examining the distribution pattern of China's carbon emissions from regional and sectoral perspectives and revealing the driving factors of China's soaring emission increase. Further, the book investigates the supply chain carbon emissions (the carbon footprints) of China's industrial sectors. Anthropogenic climate change is one of the most serious challenges currently facing humankind. China is the world's largest developing country, top primary energy consumer and carbon emitter. Achieving both economic growth and environmental conservation is the country's twofold challenge. Understanding the status, features and driving forces of China's energy-related carbon emissions is a critical aspect of attaining global sustainability. This work, for the first time, presents both key findings on and a systematic evaluation of China's carbon emissions from energy consumption. The results have important implications for global carbon budgets and burden-sharing with regard to climate change mitigation. The book will be of great interest to readers around the world, as it addresses a topic of truly global significance.

  12. Carbon emissions in China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhu [Harvard Univ., Cambridge, MA (United States). Sustainability Science Program

    2016-07-01

    This study analyzes the spatial-temporal pattern and processes of China's energy-related carbon emissions. Based on extensive quantitative analysis, it outlines the character and trajectory of China's energy-related carbon emissions during the period 1995-2010, examining the distribution pattern of China's carbon emissions from regional and sectoral perspectives and revealing the driving factors of China's soaring emission increase. Further, the book investigates the supply chain carbon emissions (the carbon footprints) of China's industrial sectors. Anthropogenic climate change is one of the most serious challenges currently facing humankind. China is the world's largest developing country, top primary energy consumer and carbon emitter. Achieving both economic growth and environmental conservation is the country's twofold challenge. Understanding the status, features and driving forces of China's energy-related carbon emissions is a critical aspect of attaining global sustainability. This work, for the first time, presents both key findings on and a systematic evaluation of China's carbon emissions from energy consumption. The results have important implications for global carbon budgets and burden-sharing with regard to climate change mitigation. The book will be of great interest to readers around the world, as it addresses a topic of truly global significance.

  13. Line ratios and wavelengths of helium-like argon n=2 satellite transitions and resonance lines

    International Nuclear Information System (INIS)

    Biedermann, C.; Radtke, R.; Fournier, K.

    2003-01-01

    The characteristic X-ray emission from helium-like argon was investigated as a mean to diagnose hot plasmas. We have measured the radiation from n=2-1 parent lines and from KLn dielectronic recombination satellites with high wavelength resolution as function of the excitation energy using the Berlin Electron Beam Ion Trap. Values of wavelength relative to the resonance and forbidden line are tabulated and compared with references. The line intensity observed over a wide range of excitation energies is weighted with a Maxwellian electron-energy distribution to analyze line ratios as function of plasma temperature. Line ratios (j+z)/w and k/w compare nicely with theoretical predictions and demonstrate their applicability as temperature diagnostic. The ratio z/(x+y) shows not to depend on the electron density

  14. A compact design for monochromatic OSL measurements in the wavelength range 380-1020 NM

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Poolton, N.R.J.; Willumsen, F.

    1994-01-01

    automated Riso TL/OSL dating apparatus, thus allowing for either routine scanning or more detailed thermo-optical investigations. The high throughput efficiency of the unit means that the existing 75 W tungsten-halogen lamp can be directly used for such measurements on both quartz and feldspar samples......The development and performance of a compact module is described that allows for the monochromatic illumination of samples in the wavelength range 380-1020 nm, enabling the measurement of energy-resolved optically stimulated luminescence. The unit is designed to couple directly to the existing....... The design allows for rapid spectral scanning with a choice of resolution of anywhere between 10 and 80 nm: stray light levels are less than 0.01%. The unit can equally be used for recording wavelength-resolved emission spectra, whether photo-excited or thermally stimulated; the capabilities of the system...

  15. Multi-wavelength Observations of the Enduring Type IIn Supernovae 2005ip and 2006jd

    DEFF Research Database (Denmark)

    Stritzinger, Maximilian; Taddia, Francesco; Fransson, Claes

    2012-01-01

    We present an observational study of the Type IIn supernovae (SNe IIn) 2005ip and 2006jd. Broadband UV, optical, and near-IR photometry, and visual-wavelength spectroscopy of SN 2005ip complement and extend upon published observations to 6.5 years past discovery. Our observations of SN 2006jd...... extend from UV to mid-infrared wavelengths, and like SN 2005ip, are compared to reported X-ray measurements to understand the nature of the progenitor. Both objects display a number of similarities with the 1988Z-like subclass of SN IIn including (1) remarkably similar early- and late-phase optical...... spectra, (2) a variety of high-ionization coronal lines, (3) long-duration optical and near-IR emission, and (4) evidence of cold and warm dust components. However, diversity is apparent, including an unprecedented late-time r-band excess in SN 2006jd. The observed differences are attributed...

  16. 4.5 μm wavelength vertical external cavity surface emitting laser operating above room temperature

    Science.gov (United States)

    Rahim, M.; Khiar, A.; Felder, F.; Fill, M.; Zogg, H.

    2009-05-01

    A midinfrared vertical external cavity surface emitting laser with 4.5 μm emission wavelength and operating above room temperature has been realized. The active part consists of a single 850 nm thick epitaxial PbSe gain layer. It is followed by a 2 1/2 pair Pb1-yEuyTe/BaF2 Bragg mirror. No microstructural processing is needed. Excitation is done optically with a 1.5 μm wavelength laser. The device operates up to 45 °C with 100 ns pulses and delivers 6 mW output power at 27 °C heat-sink temperature.

  17. Metasurface axicon lens design at visible wavelengths

    Science.gov (United States)

    Alyammahi, Saleimah; Zhan, Qiwen

    2017-08-01

    The emerging field of metasurfaces is promising to realize novel optical devices with miniaturized flat format and added functionalities. Metasurfaces have been demonstrated to exhibit full control of amplitude, phase and polarization of electromagnetic waves. Using the metasurface, the wavefront of light can be manipulated permitting new functionalities such as focusing and steering of the beams and imaging. One optical component which can be designed using metasurfaces is the axicon. Axicons are conical lenses used to convert Gaussian beams into nondiffraction Bessel beams. These unique devices are utilized in different applications ranging from optical trapping and manipulation, medical imaging, and surgery. In this work, we study axicon lens design comprising of planar metasurfaces which generate non-diffracting Bessel beams at visible wavelengths. Dielectric metasurfaces have been used to achieve high efficiency and low optical loss. We measured the spot size of the resulted beams at different planes to demonstrate the non-diffraction properties of the resulted beams. We also investigated how the spot size is influenced by the axicon aperture. Furthermore, we examined the achromatic properties of the designed axicon. Comparing with the conventional lens, the metasurface axicon lens design enables the creation of flat optical device with wide range of depth of focus along its optical axis.

  18. Picosecond chronography at x-ray wavelengths

    International Nuclear Information System (INIS)

    Bird, P.R.; Bradley, D.J.; Roddie, A.G.; Sibbett, W.; Key, M.H.; Lamb, M.J.; Lewis, C.L.S.

    1975-01-01

    An ultrafast streak camera for vacuum U-V to X-ray radiation is described. Preliminary measurements on laser-produced plasmas are presented with time resolution down to 150 psecs and space resolution down to 40μm for 1keV X-ray emission from a plasma generated by 2GW laser pulses focussed on a Cu target. High sensitivity and wide spectral bandwidth is due to front surface photoemission at oblique incidence. Time resolution capability of 40 psec and simultaneous spatial resolution down to a few microns is theoretically possible with this system. (author)

  19. Emission inventory; Inventaire des emissions

    Energy Technology Data Exchange (ETDEWEB)

    Fontelle, J.P. [CITEPA, Centre Interprofessionnel Technique d`Etudes de la Pollution Atmospherique, 75 - Paris (France)

    1997-12-31

    Statistics on air pollutant (sulfur dioxide, nitrogen oxides and ammonium) emissions, acid equivalent emissions and their evolution since 1990 in the various countries of Europe and the USA, are presented. Emission data from the industrial, agricultural, transportation and power sectors are given, and comparisons are carried out between countries based on Gnp and population, pollution import/export fluxes and compliance to the previous emission reduction objectives

  20. Wavelength stabilized high pulse power laser diodes for automotive LiDAR

    Science.gov (United States)

    Knigge, A.; Klehr, A.; Wenzel, H.; Zeghuzi, A.; Fricke, J.; Maaßdorf, A.; Liero, A.; Tränkle, G.

    2018-03-01

    Diode lasers generating optical pulses with high peak power and lengths in the nanosecond range are key components of systems for free-space communication, metrology, material processing, spectroscopy, and light detection and ranging (LiDAR) as needed for object detection and autonomous driving. Automotive LiDAR systems demand additionally a good beam quality and low wavelength shift with temperature due to the wide operating temperature span. We present here internally wavelength stabilized lasers emitting ns optical pulses from an emission aperture between 30 μm and 100 μm with peak powers of tens of Watts at wavelengths around 905 nm. The vertical structure based on AlGaAs (confinement and cladding layers) and InGaAs (active quantum well) is especially optimized for pulsed operation with respect to the implementation of a surface Bragg grating with a high reflectivity. The fabricated 6 mm long distributed Bragg reflector (DBR) broad area (BA) lasers are electrically driven by an in-house developed high-speed unit generating 3 to 10 ns long nearly rectangular shaped current pulses with amplitudes of up to 250 A. Such lasers emit optical pulses with a peak power of more than 30 W at 95 A pulse current up to a temperature of 85°C with a wavelength shift as low as 65 pm/K and a lateral beam propagation factor less than 10. The influence of the lateral aperture width and the pulse length on the beam quality will be shown. A monolithic integration of 3 DBR BA lasers on a single chip whose emission can be combined into a single beam raises the output power to more than 100 W.

  1. Wavelength encoding technique for particle analyses in hematology analyzer

    Science.gov (United States)

    Rongeat, Nelly; Brunel, Patrick; Gineys, Jean-Philippe; Cremien, Didier; Couderc, Vincent; Nérin, Philippe

    2011-07-01

    The aim of this study is to combine multiple excitation wavelengths in order to improve accuracy of fluorescence characterization of labeled cells. The experimental demonstration is realized with a hematology analyzer based on flow cytometry and a CW laser source emitting two visible wavelengths. A given optical encoding associated to each wavelength allows fluorescence identification coming from specific fluorochromes and avoiding the use of noisy compensation method.

  2. Long wavelength magnetic anomalies over continental rifts in cratonic region

    Science.gov (United States)

    Friedman, S. A.; Persaud, P.; Ferre, E. C.; Martín-Hernández, F.; Feinberg, J. M.

    2017-12-01

    New collections of unaltered mantle xenoliths shed light on potential upper mantle contributions to long wavelength magnetic anomalies (LWMA) in continental rifts in cratonic / shield areas. The new material originates from the East African Rift (Tanzania), the Rio Grande Rift (U.S.A.), the Rhine Rift (Germany), and the West Antarctic Rift (Antarctica). The xenoliths sample the uppermost ( 0.2 or Fe geotherms (>60ºC/km) that are characteristic of rifted regions preclude any contribution to LWMA at depths >10 km. Hence, only upper basalts and hypovolcanic mafic sills would constitute potential magnetic sources. In contrast, the margins of these rifted regions consist of refractory cratonic domains, often characterized by oxidized sublithospheric mantle that host significant concentrations of primary magnetite. The higher NRMs of these peridotites (up to 15 A/m, Qn > 2.5) combined with much lower geotherms (as low as 15ºC/km) allows for a 5 to 10 km layer of uppermost mantle to potentially contribute to LWMA. Assuming that Qn values in rift margins are also gradient across the rift would primarily reflect thermal equilibration over time.

  3. Quantitative structural modeling on the wavelength interval (Δλ) in synchronous fluorescence spectroscopy

    Science.gov (United States)

    Samari, Fayezeh; Yousefinejad, Saeed

    2017-11-01

    Emission fluorescence spectroscopy has an extremely restricted scope of application to analyze of complex mixtures since its selectivity is reduced by the extensive spectral overlap. Synchronous fluorescence spectroscopy (SFS) is a technique enables us to analyze complex mixtures with overlapped emission and/or excitation spectra. The difference of excitation and emission wavelength of compounds (interval wavelength or Δλ) is an important characteristic in SFS. Thus a multi-parameter model was constructed to predict Δλ in 63 fluorescent compounds and the regression coefficient in training set, cross validation and test set were 0.88, 0.85 and 0.91 respectively. Furthermore, the applicability and validity of model were evaluated using different statistical methods such as y-scrambling and applicability domain. It was concluded that increasing average valence connectivity, number of Al2-NH functional group and Geary autocorrelation (lag 4) with electronegative weights can lead to increasing Δλ in the fluorescent compounds. The current study obtained an insight into the structural properties of compounds effective on their Δλ as an important parameter in SFS.

  4. An aluminium nitride light-emitting diode with a wavelength of 210 nanometres.

    Science.gov (United States)

    Taniyasu, Yoshitaka; Kasu, Makoto; Makimoto, Toshiki

    2006-05-18

    Compact high-efficiency ultraviolet solid-state light sources--such as light-emitting diodes (LEDs) and laser diodes--are of considerable technological interest as alternatives to large, toxic, low-efficiency gas lasers and mercury lamps. Microelectronic fabrication technologies and the environmental sciences both require light sources with shorter emission wavelengths: the former for improved resolution in photolithography and the latter for sensors that can detect minute hazardous particles. In addition, ultraviolet solid-state light sources are also attracting attention for potential applications in high-density optical data storage, biomedical research, water and air purification, and sterilization. Wide-bandgap materials, such as diamond and III-V nitride semiconductors (GaN, AlGaN and AlN; refs 3-10), are potential materials for ultraviolet LEDs and laser diodes, but suffer from difficulties in controlling electrical conduction. Here we report the successful control of both n-type and p-type doping in aluminium nitride (AlN), which has a very wide direct bandgap of 6 eV. This doping strategy allows us to develop an AlN PIN (p-type/intrinsic/n-type) homojunction LED with an emission wavelength of 210 nm, which is the shortest reported to date for any kind of LED. The emission is attributed to an exciton transition, and represents an important step towards achieving exciton-related light-emitting devices as well as replacing gas light sources with solid-state light sources.

  5. Performance evaluation of distributed wavelength assignment in WDM optical networks

    Science.gov (United States)

    Hashiguchi, Tomohiro; Wang, Xi; Morikawa, Hiroyuki; Aoyama, Tomonori

    2004-04-01

    In WDM wavelength routed networks, prior to a data transfer, a call setup procedure is required to reserve a wavelength path between the source-destination node pairs. A distributed approach to a connection setup can achieve a very high speed, while improving the reliability and reducing the implementation cost of the networks. However, along with many advantages, several major challenges have been posed by the distributed scheme in how the management and allocation of wavelength could be efficiently carried out. In this thesis, we apply a distributed wavelength assignment algorithm named priority based wavelength assignment (PWA) that was originally proposed for the use in burst switched optical networks to the problem of reserving wavelengths of path reservation protocols in the distributed control optical networks. Instead of assigning wavelengths randomly, this approach lets each node select the "safest" wavelengths based on the information of wavelength utilization history, thus unnecessary future contention is prevented. The simulation results presented in this paper show that the proposed protocol can enhance the performance of the system without introducing any apparent drawbacks.

  6. Absolute analytical prediction of photonic crystal guided mode resonance wavelengths

    DEFF Research Database (Denmark)

    Hermannsson, Pétur Gordon; Vannahme, Christoph; Smith, Cameron

    2014-01-01

    numerically with methods such as rigorous coupled wave analysis. Here it is demonstrated how the absolute resonance wavelengths of such structures can be predicted by analytically modeling them as slab waveguides in which the propagation constant is determined by a phase matching condition. The model...... is experimentally verified to be capable of predicting the absolute resonance wavelengths to an accuracy of within 0.75 nm, as well as resonance wavelength shifts due to changes in cladding index within an accuracy of 0.45 nm across the visible wavelength regime in the case where material dispersion is taken...

  7. Span Restoration in Optical Networks with Limited Wavelength Conversion

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Buron, Jakob Due; Andriolli, N

    2007-01-01

    Next generation optical networks provide functionalities to dynamically provision and recover connections, while emerging technologies allow for the conversion between wavelengths. These devices are however expensive and hence it is likely that only few are deployed throughout the network...... converter-saving wavelength assignment in GMPLS networks. The converter saving property of the Suggested Vector is particularly desirable in span restoration, where the pre-failure path stubs have to be merged to the restoration path at the failure-adjacent nodes. In order to avoid wavelength conversion....... Furthermore, we describe different scenarios to extend the suggested vector wavelength assignment scheme to multi-domain networks with focus on span restoration....

  8. Utility of 18F-fluoro-deoxyglucose emission tomography/computed tomography fusion imaging (18F-FDG PET/CT) in combination with ultrasonography for axillary staging in primary breast cancer

    International Nuclear Information System (INIS)

    Ueda, Shigeto; Ishida, Jiro; Abe, Yoshiyuki; Mochizuki, Hidetaka; Tsuda, Hitoshi; Asakawa, Hideki; Omata, Jiro; Fukatsu, Kazuhiko; Kondo, Nobuo; Kondo, Tadaharu; Hama, Yukihiro; Tamura, Katsumi

    2008-01-01

    Accurate evaluation of axillary lymph node (ALN) involvement is mandatory before treatment of primary breast cancer. The aim of this study is to compare preoperative diagnostic accuracy between positron emission tomography/computed tomography with 18 F-fluorodeoxyglucose ( 18 F-FDG PET/CT) and axillary ultrasonography (AUS) for detecting ALN metastasis in patients having operable breast cancer, and to assess the clinical management of axillary 18 F-FDG PET/CT for therapeutic indication of sentinel node biopsy (SNB) and preoperative systemic chemotherapy (PSC). One hundred eighty-three patients with primary operable breast cancer were recruited. All patients underwent 18 F-FDG PET/CT and AUS followed by SNB and/or ALN dissection (ALND). Using 18 F-FDG PET/CT, we studied both a visual assessment of 18 F-FDG uptake and standardized uptake value (SUV) for axillary staging. In a visual assessment of 18 F-FDG PET/CT, the diagnostic accuracy of ALN metastasis was 83% with 58% in sensitivity and 95% in specificity, and when cut-off point of SUV was set at 1.8, sensitivity, specificity, and accuracy were 36, 100, and 79%, respectively. On the other hand, the diagnostic accuracy of AUS was 85% with 54% in sensitivity and 99% in specificity. By the combination of 18 F-FDG PET/CT and AUS to the axilla, the sensitivity, specificity, and accuracy were 64, 94, and 85%, respectively. If either 18 F-FDG PET uptake or AUS was positive in allixa, the probability of axillary metastasis was high; 50% (6 of 12) in 18 F-FDG PET uptake only, 80% (4 of 5) in AUS positive only, and 100% (28 of 28) in dual positive. By the combination of AUS and 18 F-FDG PET/CT, candidates of SNB were more appropriately selected. The axillary 18 F-FDG uptake was correlated with the maximum size and nuclear grade of metastatic foci (p = 0.006 and p = 0.03). The diagnostic accuracy of 18 F-FDG PET/CT was shown to be nearly equal to ultrasound, and considering their limited sensitivities, the high radiation

  9. Prognostic Role of Pre–Radiation Therapy {sup 18}F-Fluorodeoxyglucose Positron Emission Tomography for Primary Mediastinal B-Cell Lymphomas Treated with R-CHOP or R-CHOP-Like Chemotherapy Plus Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Filippi, Andrea Riccardo, E-mail: andreariccardo.filippi@unito.it [Department of Oncology, University of Torino, Torino (Italy); Piva, Cristina; Levis, Mario [Department of Oncology, University of Torino, Torino (Italy); Chiappella, Annalisa [Hematology, Città della Salute e della Scienza, Torino (Italy); Caracciolo, Daniele [Hematology, Città della Salute e della Scienza and University of Torino, Torino (Italy); Bellò, Marilena [Nuclear Medicine, Città della Salute e della Scienza, Torino (Italy); Bisi, Gianni [Nuclear Medicine, Città della Salute e della Scienza, Torino (Italy); Department of Medical Sciences, University of Torino, Torino (Italy); Vitolo, Umberto [Hematology, Città della Salute e della Scienza, Torino (Italy); Ricardi, Umberto [Department of Oncology, University of Torino, Torino (Italy)

    2016-07-15

    Purpose: To validate, in a monoinstitutional cohort with extended follow-up, that post–rituximab chemotherapy (R-CT) {sup 18}F-fluorodeoxyglucose positron emission tomography ({sup 18}FDG-PET) is a prognostic factor allowing discrimination of primary mediastinal B-cell lymphoma (PMBCL) patients at higher risk for progression after radiation therapy. Methods and Materials: We analyzed 51 patients, and {sup 18}FDG-PET scans were re-examined evaluating both the Deauville 5-point scale (D5PS) score and the standardized uptake value (SUV) of residual activity, if present. These parameters were then tested by univariate analysis for a potential correlation with progression-free survival (PFS) as the primary study endpoint. Results: Median follow-up time was 51 months (range, 9-153 months). After R-CT, D5PS score was 1 in 10 (19.6%), 2 in 11 (21.6%), 3 in 7 (13.8%), 4 in 17 (33.3%), and 5 in 6 patients (11.7%). Forty-three out of 51 patients (84.3%) had an SUV{sub max} ≤5, and 8 out of 51 (15.7%) had an SUV{sub max} ≥5. Overall, 6 patients experienced progression or relapse: 1 had a D5PS score 2 (with SUV{sub max} ≤5), and 5 had a D5PS score 5 (and SUV{sub max} ≥5). Patients with a D5PS score 5 showed significantly lower PFS rates versus all other scores (log-rank P<.001), as did patients with SUV{sub max} ≥5 when compared with those with SUV{sub max} ≤5 (log-rank P<.001). Conclusions: The present study confirmed the prognostic role of {sup 18}FDG-PET after R-CT, with patients with a D5PS score of 5 and/or an SUV{sub max} ≥5 being at high risk of progression/relapse after RT.

  10. Utility of 18F-fluoro-deoxyglucose emission tomography/computed tomography fusion imaging (18F-FDG PET/CT in combination with ultrasonography for axillary staging in primary breast cancer

    Directory of Open Access Journals (Sweden)

    Tamura Katsumi

    2008-06-01

    Full Text Available Abstract Background Accurate evaluation of axillary lymph node (ALN involvement is mandatory before treatment of primary breast cancer. The aim of this study is to compare preoperative diagnostic accuracy between positron emission tomography/computed tomography with 18F-fluorodeoxyglucose (18F-FDG PET/CT and axillary ultrasonography (AUS for detecting ALN metastasis in patients having operable breast cancer, and to assess the clinical management of axillary 18F-FDG PET/CT for therapeutic indication of sentinel node biopsy (SNB and preoperative systemic chemotherapy (PSC. Methods One hundred eighty-three patients with primary operable breast cancer were recruited. All patients underwent 18F-FDG PET/CT and AUS followed by SNB and/or ALN dissection (ALND. Using 18F-FDG PET/CT, we studied both a visual assessment of 18F-FDG uptake and standardized uptake value (SUV for axillary staging. Results In a visual assessment of 18F-FDG PET/CT, the diagnostic accuracy of ALN metastasis was 83% with 58% in sensitivity and 95% in specificity, and when cut-off point of SUV was set at 1.8, sensitivity, specificity, and accuracy were 36, 100, and 79%, respectively. On the other hand, the diagnostic accuracy of AUS was 85% with 54% in sensitivity and 99% in specificity. By the combination of 18F-FDG PET/CT and AUS to the axilla, the sensitivity, specificity, and accuracy were 64, 94, and 85%, respectively. If either 18F-FDG PET uptake or AUS was positive in allixa, the probability of axillary metastasis was high; 50% (6 of 12 in 18F-FDG PET uptake only, 80% (4 of 5 in AUS positive only, and 100% (28 of 28 in dual positive. By the combination of AUS and 18F-FDG PET/CT, candidates of SNB were more appropriately selected. The axillary 18F-FDG uptake was correlated with the maximum size and nuclear grade of metastatic foci (p = 0.006 and p = 0.03. Conclusion The diagnostic accuracy of 18F-FDG PET/CT was shown to be nearly equal to ultrasound, and considering their

  11. Spectral emissivity of surface blackbody calibrators

    DEFF Research Database (Denmark)

    Clausen, Sønnik

    2007-01-01

    The normal spectral emissivity of commercial infrared calibrators is compared with measurements of anodized aluminum samples and grooved aluminum surfaces coated with Pyromark. Measurements performed by FTIR spectroscopy in the wavelength interval from 2 to 20 mu m and at temperatures between 5...

  12. S – C – L triple wavelength superluminescent source based on an ultra-wideband SOA and FBGs

    International Nuclear Information System (INIS)

    Ahmad, H; Zulkifli, M Z; Hassan, N A; Muhammad, F D; Harun, S W

    2013-01-01

    We propose and demonstrate a wide-band semiconductor optical amplifier (SOA) based triple-wavelength superluminescent source with the output in the S-, C- and L-band regions. The proposed systems uses an ultra-wideband SOA with an amplification range from 1440 to 1620 nm as the linear gain medium. Three fibre Bragg gratings (FBGs) with centre wavelengths of 1500, 1540 and 1580 nm are used to generate the lasing wavelengths in the S-, Cand L-bands respectively, while a variable optical attenuator is used to finely balance the optical powers of the lasing wavelengths. The ultra-wideband SOA generates an amplified spontaneous emission (ASE) spectrum with a peak power of -33 dBm at the highest SOA drive current, and also demonstrates a down-shift in the centre wavelength of the generated spectrum due to the spatial distribution of the carrier densities. The S-band wavelength is the dominant wavelength at high drive currents, with an output power of -6 dBm as compared to the C- and L-bands, which only have powers of -11 and -10 dBm, respectively. All wavelengths have a high average signal-to-noise ratio more than 60 dB at the highest drive current of 390 mA, and the system also shows a high degree of stability, with power fluctuations of less than 3 dB within 70 min. The proposed system can find many applications where a wide-band and stable laser source is crucial, such as in communications and sensing. (control of laser radiation parameters)

  13. S – C – L triple wavelength superluminescent source based on an ultra-wideband SOA and FBGs

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, H; Zulkifli, M Z; Hassan, N A; Muhammad, F D; Harun, S W [Photonics Research Center (Department of Physics), University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2013-10-31

    We propose and demonstrate a wide-band semiconductor optical amplifier (SOA) based triple-wavelength superluminescent source with the output in the S-, C- and L-band regions. The proposed systems uses an ultra-wideband SOA with an amplification range from 1440 to 1620 nm as the linear gain medium. Three fibre Bragg gratings (FBGs) with centre wavelengths of 1500, 1540 and 1580 nm are used to generate the lasing wavelengths in the S-, Cand L-bands respectively, while a variable optical attenuator is used to finely balance the optical powers of the lasing wavelengths. The ultra-wideband SOA generates an amplified spontaneous emission (ASE) spectrum with a peak power of -33 dBm at the highest SOA drive current, and also demonstrates a down-shift in the centre wavelength of the generated spectrum due to the spatial distribution of the carrier densities. The S-band wavelength is the dominant wavelength at high drive currents, with an output power of -6 dBm as compared to the C- and L-bands, which only have powers of -11 and -10 dBm, respectively. All wavelengths have a high average signal-to-noise ratio more than 60 dB at the highest drive current of 390 mA, and the system also shows a high degree of stability, with power fluctuations of less than 3 dB within 70 min. The proposed system can find many applications where a wide-band and stable laser source is crucial, such as in communications and sensing. (control of laser radiation parameters)

  14. Single-Institution Experience in the Treatment of Primary Mediastinal B Cell Lymphoma Treated With Immunochemotherapy in the Setting of Response Assessment by {sup 18}Fluorodeoxyglucose Positron Emission Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Pinnix, Chelsea C. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Dabaja, Bouthaina, E-mail: bdabaja@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Ahmed, Mohamed Amin [Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chuang, Hubert H. [Department of Nuclear Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Costelloe, Colleen [Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wogan, Christine F.; Reed, Valerie [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Romaguera, Jorge E.; Neelapu, Sattva; Oki, Yasuhiro [Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Rodriguez, M. Alma [Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Office of Medical Affairs, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Fayad, Luis; Hagemeister, Frederick B.; Nastoupil, Loretta; Turturro, Francesco; Fowler, Nathan; Fanale, Michelle A. [Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Nieto, Yago; Khouri, Issa F.; Ahmed, Sairah [Department of Stem Cell Transplantation, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); and others

    2015-05-01

    Purpose: Excellent outcomes obtained after infusional dose-adjusted etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, and rituximab (R-EPOCH) alone have led some to question the role of consolidative radiation therapy (RT) in the treatment of primary mediastinal B cell lymphoma (PMBL). We reviewed the outcomes in patients treated with 1 of 3 rituximab-containing regimens (cyclophosphamide, doxorubicin, vincristine, prednisone [R-CHOP]; hyperfractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone [R-HCVAD], or R-EPOCH) with or without RT. We also evaluated the ability of positron emission tomography–computed tomography (PET-CT) to identify patients at risk of relapse. Methods and Materials: We retrospectively identified 97 patients with diagnoses of stage I/II PMBCL treated at our institution between 2001 and 2013. The clinical characteristics, treatment outcomes, and toxicity were assessed. We analyzed whether postchemotherapy PET-CT could identify patients at risk for progressive disease according to a 5 point scale (5PS) Deauville score assigned. Results: Among 97 patients (median follow-up time, 57 months), the 5-year overall survival rate was 99%. Of patients treated with R-CHOP, 99% received RT; R-HCVAD, 82%; and R-EPOCH, 36%. Of 68 patients with evaluable end-of-chemotherapy PET-CT scans, 62% had a positive scan (avidity above that of the mediastinal blood pool [Deauville 5PS = 3]), but only 9 patients experienced relapse (n=1) or progressive disease (n=8), all with a 5PS of 4 to 5. Of the 25 patients who received R-EPOCH, 4 experienced progression, all with 5PS of 4 to 5; salvage therapy (RT and autologous stem cell transplantation) was successful in all cases. Conclusion: Combined modality immunochemotherapy and RT is well tolerated and effective for treatment of PMBCL. A postchemotherapy 5PS of 4 to 5, rather than 3 to 5, can identify patients at high risk of progression who should be considered for therapy beyond

  15. Critical de Broglie wavelength in superconductors

    Science.gov (United States)

    Talantsev, E. F.

    2018-03-01

    There are growing numbers of experimental evidences that the self-field critical currents, Jc(sf,T), are a new instructive tool to investigate fundamental properties of superconductors ranging from atomically thin films [M. Liao et al., Nat. Phys. 6 (2018), https://doi.org/10.1038/s41567-017-0031-6; E. F. Talantsev et al., 2D Mater. 4 (2017) 025072; A. Fete et al., Appl. Phys. Lett. 109 (2016) 192601] to millimeter-scale samples [E. F. Talantsev et al., Sci. Rep. 7 (2017) 10010]. The basic empirical equation which quantitatively accurately described experimental Jc(sf,T) was proposed by Talantsev and Tallon [Nat. Commun. 6 (2015) 7820] and it was the relevant critical field (i.e. thermodynamic field, Bc, for type-I and lower critical field, Bc1, for type-II superconductors) divided by the London penetration depth, λL. In this paper, we report new findings relating to this empirical equation. It is that the critical wavelength of the de Broglie wave, λdB,c, of the superconducting charge carrier which within a numerical pre-factor is equal to the largest of two characteristic lengths of Ginzburg-Landau theory, i.e. the coherence length, ξ, for type-I superconductors or the London penetration depth, λL, for type-II superconductors. We also formulate a microscopic criterion for the onset of dissipative transport current flow: ps ṡ 2ṡλL ln(1+2ṡ(λL ξ )) ≥ 1 2 ṡ ( h 2π), where ps is the charge carrier momentum, h is Planck’s constant and the inequality sign “ <” is reserved for the dissipation-free flow.

  16. Colloidal PbS nanocrystals integrated to Si-based photonics for applications at telecom wavelengths

    Science.gov (United States)

    Humer, M.; Guider, R.; Jantsch, W.; Fromherz, T.

    2013-05-01

    In the last decade, Si based photonics has made major advances in terms of design, fabrication, and device implementation. But due to Silicon's indirect bandgap, it still remains a challenge to create efficient Si-based light emitting devices. In order to overcome this problem, an approach is to develop hybrid systems integrating light-emitting materials into Si. A promising class of materials for this purpose is the class of semiconducting nanocrystal quantum dots (NCs) that are synthesized by colloidal chemistry. As their absorption and emission wavelength depends on the dot size, which can easily be controlled during synthesis, they are extremely attractive as building blocks for nanophotonic applications. For applications in telecom wavelength, Lead chalcogenide colloidal NCs are optimum materials due to their unique optical, electronic and nonlinear properties. In this work, we experimentally demonstrate the integration of PbS nanocrystals into Si-based photonic structures like slot waveguides and ring resonators as optically pumped emitters for room temperature applications. In order to create such hybrid structures, the NCs were dissolved into polymer resists and drop cast on top of the device. Upon optical pumping, intense photoluminescence emission from the resonating modes is recorded at the output of the waveguide with transmission quality factors up to 14000. The polymer host material was investigated with respect to its ability to stabilize the NC's photoluminescence emission against degradation under ambient conditions. The waveguide-ring coupling efficiency was also investigated as function of the NCs concentrations blended into the polymer matrix. The integration of colloidal quantum dots into Silicon photonic structures as demonstrated in this work is a very versatile technique and thus opens a large range of applications utilizing the linear and nonlinear optical properties of PbS NCs at telecom wavelengths.

  17. Compactly packaged monolithic four-wavelength VCSEL array with 100-GHz wavelength spacing for future-proof mobile fronthaul transport.

    Science.gov (United States)

    Lee, Eun-Gu; Mun, Sil-Gu; Lee, Sang Soo; Lee, Jyung Chan; Lee, Jong Hyun

    2015-01-12

    We report a cost-effective transmitter optical sub-assembly using a monolithic four-wavelength vertical-cavity surface-emitting laser (VCSEL) array with 100-GHz wavelength spacing for future-proof mobile fronthaul transport using the data rate of common public radio interface option 6. The wavelength spacing is achieved using selectively etched cavity control layers and fine current adjustment. The differences in operating current and output power for maintaining the wavelength spacing of four VCSELs are fiber without any dispersion-compensation techniques.

  18. Highly accurate Michelson type wavelength meter that uses a rubidium stabilized 1560 nm diode laser as a wavelength reference

    International Nuclear Information System (INIS)

    Masuda, Shin; Kanoh, Eiji; Irisawa, Akiyoshi; Niki, Shoji

    2009-01-01

    We investigated the accuracy limitation of a wavelength meter installed in a vacuum chamber to enable us to develop a highly accurate meter based on a Michelson interferometer in 1550 nm optical communication bands. We found that an error of parts per million order could not be avoided using famous wavelength compensation equations. Chromatic dispersion of the refractive index in air can almost be disregarded when a 1560 nm wavelength produced by a rubidium (Rb) stabilized distributed feedback (DFB) diode laser is used as a reference wavelength. We describe a novel dual-wavelength self-calibration scheme that maintains high accuracy of the wavelength meter. The method uses the fundamental and second-harmonic wavelengths of an Rb-stabilized DFB diode laser. Consequently, a highly accurate Michelson type wavelength meter with an absolute accuracy of 5x10 -8 (10 MHz, 0.08 pm) over a wide wavelength range including optical communication bands was achieved without the need for a vacuum chamber.

  19. FIMS Wavelength Calibration via Airglow Line Observations

    Directory of Open Access Journals (Sweden)

    Dae-Hee Lee

    2004-12-01

    Full Text Available Far-ultraviolet Imaging Spectrograph (FIMS is the main payload of the Korea's first scientific micro satellite STSAT-1, which was launched at Sep. 27 2003 successfully. Major objective of FIMS is observing hot gas in the Galaxy in FUV bands to diagnose the energy flow models of the interstellar medium. Supernova remnants, molecular clouds, and Aurora emission in the geomagnetic pole regions are specific targets for pointing observation. Although the whole system was calibrated before launch, it is essential to perform on-orbit calibration for data analysis. For spectral calibration, we observed airglow lines in the atmosphere since they provide good spectral references. We identify and compare the observed airglow lines with model calculations, and correct the spectral distortion appeared in the detector system to improve the spectral resolution of the system.

  20. Multi-wavelength study of young and massive galaxy clusters

    International Nuclear Information System (INIS)

    Lemonon, Ludovic

    1999-01-01

    Clusters of galaxies are the most massive objects gravitationally bound observed. They are the consequence of the evolution of most important perturbations in the cosmological microwave background. Their formation depends strongly of the cosmology, so they represent key objects to understand the Universe. The aim of this thesis is to study the processes of formation in clusters of galaxies well far away than previous studies clone, by high-resolution observations obtained by using most powerful telescope in each studied wavelength: X-ray, visible, infrared and radio. After data reductions of 12 clusters located at 0.1; z; 0.3, I was able to classified them in three categories: dynamically perturbed clusters, with substructures in their X-ray/optical image or velocity distribution of galaxies; cooling flows clusters, more relaxed than previous, with huge amount of gas cooling in their center; AGN contaminated, where the central dominant galaxy is an AGN which contaminate considerably the X-ray emission. I have obtained a measurement of the baryonic fraction of the Universe mass, and an estimation of the Universe matter density parameter at the mega-parsec scale, claiming for a low density universe. The ISOCAM data showed the effect of the ICM interactions on the star formation in cluster galaxies, and demonstrated that optical and mid-IR deduced star-formation are not basically compatible. They also showed how IR-emitting galaxies distribute in clusters, most noticeably how 15 um galaxies are located preferably on the edge of clusters. X-ray and radio data showed that clusters at z 0.25 could be find in several dynamical state, similarly with nearby ones, from relaxed to severely perturbed. All clusters present signs of past or present merging, in agreement with hierarchical structure formation scenario. This clusters database is an excellent starting point to study process of merging in clusters since they showed different aspect of this evolution. (author) [fr

  1. Multi-wavelength investigations on feedback of massive star formation

    Science.gov (United States)

    Yuan, Jinghua

    2014-05-01

    In the course of massive star formation, outflows, ionizing radiation and intense stellar winds could heavily affect their adjacent environs and natal clouds. There are several outstanding open questions related to these processes: i) whether they can drive turbulence in molecular clouds; ii) whether they are able to trigger star formation; iii) whether they can destroy natal clouds to terminate star formation at low efficiencies. This thesis investigates feedback in different stages of massive star formation. Influence of such feedback to the ambient medium has been revealed. A new type of millimeter methanol maser is detected for the first time. An uncommon bipolar outflow prominent in the mid-infrared is discovered. And features of triggered star formation are found on the border of an infrared bubble and in the surroundings of a Herbig Be star. Extended green objects (EGOs) are massive outflow candidates showing prominent shocked features in the mid-infrared. We have carried out a high resolution study of the EGO G22.04+0.22 (hereafter, G22) based on archived SMA data. Continuum and molecular lines at 1.3 mm reveal that G22 is still at a hot molecular core stage. A very young multi-polar outflow system is detected, which is interacting with the adjacent dense gas. Anomalous emission features from CH3OH (8,-1,8 - 7,0,7) and CH3OH (4,2,2 - 3,1,2) are proven to be millimeter masers. It is the first time that maser emission of CH3OH (8,-1,8 - 7,0,7) at 218.440 GHz is detected in a massive star-forming region. Bipolar outflows have been revealed and investigated almost always in the microwave or radio domain. It's sort of rare that hourglass-shaped morphology be discovered in the mid-infrared. Based on GLIMPSE data, we have discovered a bipolar object resembling an hourglass at 8.0 um. It is found to be associated with IRAS 18114-1825. Analysis based on fitted SED, optical spectroscopy, and infrared color indices suggests IRAS 18114-1825 is an uncommon bipolar

  2. Wavelength calibration of x-ray imaging crystal spectrometer on Joint Texas Experimental Tokamak

    International Nuclear Information System (INIS)

    Yan, W.; Chen, Z. Y.; Jin, W.; Huang, D. W.; Ding, Y. H.; Li, J. C.; Zhang, X. Q.; Zhuang, G.; Lee, S. G.; Shi, Y. J.

    2014-01-01

    The wavelength calibration of x-ray imaging crystal spectrometer is a key issue for the measurements of plasma rotation. For the lack of available standard radiation source near 3.95 Å and there is no other diagnostics to measure the core rotation for inter-calibration, an indirect method by using tokamak plasma itself has been applied on joint Texas experimental tokamak. It is found that the core toroidal rotation velocity is not zero during locked mode phase. This is consistent with the observation of small oscillations on soft x-ray signals and electron cyclotron emission during locked-mode phase

  3. Unselective regrowth buried heterostructure long-wavelength superluminescent diode realized with MOVPE

    Energy Technology Data Exchange (ETDEWEB)

    Ding Ying [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)]. E-mail: yingding@red.semi.ac.cn; Zhou Fan [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Chen Weixi [School of Physics, Peking University, Beijing 100871 (China); Wang Wei [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    2007-01-15

    A novel unselective regrowth buried heterostructure (BH) long-wavelength superluminescent diode (SLD), which has a grade-strained bulk InGaAs active region, was developed by metalorganic vapor-phase epitaxy (MOVPE). The 3 dB emission spectrum bandwidth of the SLD is about 65 nm with the range from 1596 to 1661 nm at 90 mA and from 1585 to 1650 nm at 150 mA.An output power of 3.5 mW is obtained at 200 mA injection current under CW operation at room temperature.

  4. High-quality asynchronous heralded single-photon source at telecom wavelength

    International Nuclear Information System (INIS)

    Fasel, Sylvain; Alibart, Olivier; Tanzilli, Sebastien; Baldi, Pascal; Beveratos, Alexios; Gisin, Nicolas; Zbinden, Hugo

    2004-01-01

    We report on the experimental realization and characterization of an asynchronous heralded single-photon source based on spontaneous parametric down-conversion. Photons at 1550 nm are heralded as being inside a single-mode fibre with more than 60% probability, and the multi-photon emission probability is reduced by a factor of up to more than 500 compared to Poissonian light sources. These figures of merit, together with the choice of telecom wavelength for the heralded photons, are compatible with practical applications needing very efficient and robust single-photon sources

  5. Wavelength modulated surface enhanced (resonance) Raman scattering for background-free detection.

    Science.gov (United States)

    Praveen, Bavishna B; Steuwe, Christian; Mazilu, Michael; Dholakia, Kishan; Mahajan, Sumeet

    2013-05-21

    Spectra in surface-enhanced Raman scattering (SERS) are always accompanied by a continuum emission called the 'background' which complicates analysis and is especially problematic for quantification and automation. Here, we implement a wavelength modulation technique to eliminate the background in SERS and its resonant version, surface-enhanced resonance Raman scattering (SERRS). This is demonstrated on various nanostructured substrates used for SER(R)S. An enhancement in the signal to noise ratio for the Raman bands of the probe molecules is also observed. This technique helps to improve the analytical ability of SERS by alleviating the problem due to the accompanying background and thus making observations substrate independent.

  6. Selective emission multilayer coatings for a molybdenum thermophotovoltaic radiator

    Science.gov (United States)

    Cockeram, Brian Vern

    2004-01-27

    Multilayer coating designs have been developed to provide selective emission for a molybdenum thermophotovoltaic (TPV) radiator surface. These coatings increase the surface emissivity of a molybdenum TPV radiator substrate in the wavelength range that matches the bandgap of the TPV cells to increase the power density of the TPV system. Radiator emission at wavelengths greater than the bandgap energy of the TPV cells is greatly reduced through the use of these coatings, which significantly increases the efficiency of the TPV system. The use of this coating greatly improves the performance of a TPV system, and the coating can be tailored to match the bandgap of any practical TPV system.

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

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  8. Technologies for all-optical wavelength conversion in DWDM networks

    DEFF Research Database (Denmark)

    Wolfson, David; Fjelde, Tina; Kloch, Allan

    2001-01-01

    Different techniques for all-optical wavelength conversion are reviewed and the advantages and disadvantages seen from a system perspective are highlighted. All-optical wavelength conversion will play a major role in making cost-effective network nodes in future high-speed WDM networks, where...

  9. Experimental determination of the slow-neutron wavelength distribution

    DEFF Research Database (Denmark)

    Lebech, Bente; Mikke, K.; Sledziewska-Blocka, D.

    1970-01-01

    Different experiments for determining the slow-neutron wavelength distribution in the region 227-3 meV have been carried out, and the results compared. It is concluded that the slow-neutron wave-length distribution can be determined accurately by elastic scattering on a pure incoherent or a pure...

  10. Sub-wavelength resonances in polygonal metamaterial cylinders

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Breinbjerg, Olav

    2008-01-01

    It has been shown that the sub-wavelength resonances of circular MTM cylinders also occur for polygonal MTM cylinders. This is the case for lossless and non-dispersive cylinders as well as lossy and dispersive cylinders. The sub-wavelength resonances are thus not limited to structures of canonical...

  11. Systematic wavelength selection for improved multivariate spectral analysis

    Science.gov (United States)

    Thomas, Edward V.; Robinson, Mark R.; Haaland, David M.

    1995-01-01

    Methods and apparatus for determining in a biological material one or more unknown values of at least one known characteristic (e.g. the concentration of an analyte such as glucose in blood or the concentration of one or more blood gas parameters) with a model based on a set of samples with known values of the known characteristics and a multivariate algorithm using several wavelength subsets. The method includes selecting multiple wavelength subsets, from the electromagnetic spectral region appropriate for determining the known characteristic, for use by an algorithm wherein the selection of wavelength subsets improves the model's fitness of the determination for the unknown values of the known characteristic. The selection process utilizes multivariate search methods that select both predictive and synergistic wavelengths within the range of wavelengths utilized. The fitness of the wavelength subsets is determined by the fitness function F=.function.(cost, performance). The method includes the steps of: (1) using one or more applications of a genetic algorithm to produce one or more count spectra, with multiple count spectra then combined to produce a combined count spectrum; (2) smoothing the count spectrum; (3) selecting a threshold count from a count spectrum to select these wavelength subsets which optimize the fitness function; and (4) eliminating a portion of the selected wavelength subsets. The determination of the unknown values can be made: (1) noninvasively and in vivo; (2) invasively and in vivo; or (3) in vitro.

  12. Sub-wavelength metamaterial cylinders with multiple dipole resonances

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Breinbjerg, Olav

    2009-01-01

    It has been shown that the sub-wavelength resonances of the individual MTM cylinders also occur for electrically small configurations combining 2 or 4 cylinders. For the 2-and 4-cylinder configurations the overall size is 1/20 and 1/12.5 of the smallest wavelength, respectively. These MTM...... configuration thus offer the possibility for multi-resonant electrically small configurations....

  13. Modulating wavelength discrimination in goldfish with ethambutol and stimulus intensity

    NARCIS (Netherlands)

    Sjoerdsma, T.; Kamermans, M.; Spekreijse, H.

    1996-01-01

    Wavelength discrimination in goldfish was measured behaviourally. Both acute application of ethambutol injected into the eye and chronic application by feeding the animals daily 25 mg ethambutol for 1 month had the same effect on wavelength discrimination in the range of 560-640 nm. This means that:

  14. Optimal wavelength band clustering for multispectral iris recognition.

    Science.gov (United States)

    Gong, Yazhuo; Zhang, David; Shi, Pengfei; Yan, Jingqi

    2012-07-01

    This work explores the possibility of clustering spectral wavelengths based on the maximum dissimilarity of iris textures. The eventual goal is to determine how many bands of spectral wavelengths will be enough for iris multispectral fusion and to find these bands that will provide higher performance of iris multispectral recognition. A multispectral acquisition system was first designed for imaging the iris at narrow spectral bands in the range of 420 to 940 nm. Next, a set of 60 human iris images that correspond to the right and left eyes of 30 different subjects were acquired for an analysis. Finally, we determined that 3 clusters were enough to represent the 10 feature bands of spectral wavelengths using the agglomerative clustering based on two-dimensional principal component analysis. The experimental results suggest (1) the number, center, and composition of clusters of spectral wavelengths and (2) the higher performance of iris multispectral recognition based on a three wavelengths-bands fusion.

  15. Planck 2013 results. XIV. Zodiacal emission

    OpenAIRE

    Ade, PAR; Aghanim, N; Armitage-Caplan, C; Arnaud, M; Ashdown, M; Atrio-Barandela, F; Aumont, J; Baccigalupi, C; Banday, AJ; Barreiro, RB; Bartlett, JG; Battaner, E; Benabed, K; Benoît, A; Benoit-Lévy, A

    2014-01-01

    © 2014 ESO. The Planck satellite provides a set of all-sky maps at nine frequencies from 30GHz to 857GHz. Planets, minor bodies, and diffuse interplanetary dust emission (IPD) are all observed. The IPD can be separated from Galactic and other emissions because Planck views a given point on the celestial sphere multiple times, through different columns of IPD. We use the Planck data to investigate the behaviour of zodiacal emission over the whole sky at sub-millimetre and millimetre wavelength...

  16. NASA Wavelength: A Digital Library for Earth and Space Science Education

    Science.gov (United States)

    Schwerin, T.; Peticolas, L. M.; Bartolone, L. M.; Davey, B.; Porcello, D.

    2012-12-01

    The NASA Science Education and Public Outreach Forums have developed a web-based information system - NASA Wavelength - that will enable easy discovery and retrieval of thousands of resources from the NASA Earth and space science education portfolio. The beta system is being launched fall 2012 and has been developed based on best-practices in the architecture and design of Web-based information systems. The design style and philosophy emphasize simple, reusable data and services that facilitate the free-flow of data across systems. The primary audiences for NASA Wavelength are STEM educators (K-12, higher education and informal education) as well as scientists, education and public outreach professionals who work with k-12, higher education and informal education.

  17. Towards shorter wavelength x-ray lasers using a high power, short pulse pump laser

    International Nuclear Information System (INIS)

    Tighe, W.; Krushelnick, K.; Valeo, E.; Suckewer, S.

    1991-05-01

    A near-terawatt, KrF* laser system, focussable to power densities >10 18 W/cm 2 has been constructed for use as a pump laser in various schemes aimed at the development of x-ray lasing below 5nm. The laser system along with output characteristics such as the pulse duration, the focal spot size, and the percentage of amplified spontaneous emission (ASE) emitted along with the laser pulse will be presented. Schemes intended to lead to shorter wavelength x-ray emission will be described. The resultant requirements on the pump laser characteristics and the target design will be outlined. Results from recent solid target experiments and two-laser experiments, showing the interaction of a high-power, short pulse laser with a preformed plasma, will be presented. 13 refs., 5 figs

  18. Optically stimulated luminescence emission spectra from feldspars as a function of sample temperature

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.

    1997-01-01

    samples have been measured at various sample temperatures. A small but consistent shift of the peak emission wavelength to shorter wavelengths at higher temperatures is observed. However, the magnitude of this shift is sufficiently small that it will not affect measurements of the thermal activation...... energy. A systematic difference is observed between the thermal activation energies measured when using different emission wavelengths. In particular, the thermal activation energy of the emission at 400 nm is typically 0.11 eV, while that at 570 nm from the same samples is 0.03-0.05 eV. Several possible...

  19. Geometrical differences in target volumes based on 18F-fluorodeoxyglucose positron emission tomography/computed tomography and four-dimensional computed tomography maximum intensity projection images of primary thoracic esophageal cancer.

    Science.gov (United States)

    Guo, Y; Li, J; Wang, W; Zhang, Y; Wang, J; Duan, Y; Shang, D; Fu, Z

    2014-01-01

    The objective of the study was to compare geometrical differences of target volumes based on four-dimensional computed tomography (4DCT) maximum intensity projection (MIP) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) images of primary thoracic esophageal cancer for radiation treatment. Twenty-one patients with thoracic esophageal cancer sequentially underwent contrast-enhanced three-dimensional computed tomography (3DCT), 4DCT, and 18F-FDG PET/CT thoracic simulation scans during normal free breathing. The internal gross target volume defined as IGTVMIP was obtained by contouring on MIP images. The gross target volumes based on PET/CT images (GTVPET ) were determined with nine different standardized uptake value (SUV) thresholds and manual contouring: SUV≥2.0, 2.5, 3.0, 3.5 (SUVn); ≥20%, 25%, 30%, 35%, 40% of the maximum (percentages of SUVmax, SUVn%). The differences in volume ratio (VR), conformity index (CI), and degree of inclusion (DI) between IGTVMIP and GTVPET were investigated. The mean centroid distance between GTVPET and IGTVMIP ranged from 4.98 mm to 6.53 mm. The VR ranged from 0.37 to 1.34, being significantly (P<0.05) closest to 1 at SUV2.5 (0.94), SUV20% (1.07), or manual contouring (1.10). The mean CI ranged from 0.34 to 0.58, being significantly closest to 1 (P<0.05) at SUV2.0 (0.55), SUV2.5 (0.56), SUV20% (0.56), SUV25% (0.53), or manual contouring (0.58). The mean DI of GTVPET in IGTVMIP ranged from 0.61 to 0.91, and the mean DI of IGTVMIP in GTVPET ranged from 0.34 to 0.86. The SUV threshold setting of SUV2.5, SUV20% or manual contouring yields the best tumor VR and CI with internal-gross target volume contoured on MIP of 4DCT dataset, but 3DPET/CT and 4DCT MIP could not replace each other for motion encompassing target volume delineation for radiation treatment. © 2014 International Society for Diseases of the Esophagus.

  20. Planck 2013 results. XIV. Zodiacal emission

    CERN Document Server

    Ade, P A R; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Bartlett, J.G.; Battaner, E.; Benabed, K.; Benoit, A.; Benoit-Levy, A.; Bernard, J.P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J.J.; Bonaldi, A.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Boulanger, F.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R.C.; Cardoso, J.F.; Catalano, A.; Chamballu, A.; Chary, R.-R.; Chen, X.; Chiang, L.Y.; Chiang, H.C.; Christensen, P.R.; Church, S.; Clements, D.L.; Colley, J.-M.; Colombi, S.; Colombo, L.P.L.; Couchot, F.; Coulais, A.; Crill, B.P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.M.; Desert, F.X.; Dickinson, C.; Diego, J.M.; Dole, H.; Donzelli, S.; Dore, O.; Douspis, M.; Dupac, X.; Efstathiou, G.; Ensslin, T.A.; Eriksen, H.K.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giraud-Heraud, Y.; Gonzalez-Nuevo, J.; Gorski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, F.K.; Hanson, D.; Harrison, D.; Helou, G.; Henrot-Versille, S.; Hernandez-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Jaffe, T.R.; Jaffe, A.H.; Jones, W.C.; Juvela, M.; Keihanen, E.; Keskitalo, R.; Kisner, T.S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lahteenmaki, A.; Lamarre, J.M.; Lasenby, A.; Laureijs, R.J.; Lawrence, C.R.; Leonardi, R.; Lesgourgues, J.; Liguori, M.; Lilje, P.B.; Linden-Vornle, M.; Lopez-Caniego, M.; Lubin, P.M.; Macias-Perez, J.F.; Maffei, B.; Maino, D.; Mandolesi, N.; Maris, M.; Marshall, D.J.; Martin, P.G.; Martinez-Gonzalez, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; Meinhold, P.R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschenes, M.A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Mottet, S.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Norgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; O'Sullivan, C.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polegre, A. M.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G.W.; Prezeau, G.; Prunet, S.; Puget, J.L.; Rachen, J.P.; Reach, W.T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Seiffert, M.D.; Shellard, E.P.S.; Smoot, G. F.; Spencer, L.D.; Starck, J.L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.S.; Sygnet, J.F.; Tauber, J.A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L.A.; Wandelt, B.D.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-01-01

    The Planck satellite provides a set of all-sky maps at nine frequencies from 30 GHz to 857 GHz. Planets, minor bodies, and diffuse interplanetary dust emission (IPD) are all observed. The IPD can be separated from Galactic and other emissions because Planck views a given point on the celestial sphere multiple times, through different columns of IPD. We use the Planck data to investigate the behaviour of zodiacal emission over the whole sky at sub-millimetre and millimetre wavelengths. We fit the Planck data to find the emissivities of the various components of the COBE zodiacal model -- a diffuse cloud, three asteroidal dust bands, a circumsolar ring, and an Earth-trailing feature. The emissivity of the diffuse cloud decreases with increasing wavelength, as expected from earlier analyses. The emissivities of the dust bands, however, decrease less rapidly, indicating that the properties of the grains in the bands are different from those in the diffuse cloud. We fit the small amount of Galactic emission seen t...

  1. Multi-wavelength studies of TeV γ-ray emitting BL Lac objects

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, Sarah Sabine

    2012-12-21

    The discovery of TeV γ-ray emission of BL Lac objects gave new insights in the particle acceleration and the emission processes of the highly relativistic jets. To shed light on the conditions in the high energetic jets of the TeV γ-ray emitting BL Lac objects, I have studied in great detail the spectral energy distribution (SED) of sources with different characteristics. BL Lac objects with exceptional very high energy spectra (soft and hard spectra) and with large differences in the emission peak frequencies, to cover the different classes of BL Lac objects, have been chosen. The basic aim of this thesis was, to study with new, simultaneous multi- avelength (MWL) observations, if the emission processes of these extreme cases of TeV BL Lac objects can be explained by the synchrotron Self-Compton (SSC) model which is well established for the class of BL Lac objects at lower energies. We proposed MWL observations in the optical, UV and X-ray regime, to be conducted simultaneous to very high energy observations with the H.E.S.S. experiment, to study the emission processes. Simultaneous observations are crucial, since BL Lac objects are variable at all wavebands. I have analysed the MWL observations and conducted detailed variability and spectral studies in each wavelength range. The different kind of absorption at each wavelength as well as the influence of the host galaxy of the AGN has been considered to obtain the intrinsic jet spectrum. I have then applied the commonly used theoretical jet model, the SSC model, to the SED. I conducted a MWL campaign on a BL Lac object with the softest TeV spectrum, PKS 2005-489, during which it was observed in a very bright X-ray state. The good spectral coverage of the emission peaks allowed a detailed study of the SSC model. The extreme BL Lac object 1ES 0229+200 exhibits a hard intrinsic TeV spectrum. With my MWL campaign I found a clear cut-off in the optical range and therefore a high minimum Lorentz factor is needed to

  2. Multi-wavelength studies of TeV γ-ray emitting BL Lac objects

    International Nuclear Information System (INIS)

    Kaufmann, Sarah Sabine

    2012-01-01

    The discovery of TeV γ-ray emission of BL Lac objects gave new insights in the particle acceleration and the emission processes of the highly relativistic jets. To shed light on the conditions in the high energetic jets of the TeV γ-ray emitting BL Lac objects, I have studied in great detail the spectral energy distribution (SED) of sources with different characteristics. BL Lac objects with exceptional very high energy spectra (soft and hard spectra) and with large differences in the emission peak frequencies, to cover the different classes of BL Lac objects, have been chosen. The basic aim of this thesis was, to study with new, simultaneous multi- avelength (MWL) observations, if the emission processes of these extreme cases of TeV BL Lac objects can be explained by the synchrotron Self-Compton (SSC) model which is well established for the class of BL Lac objects at lower energies. We proposed MWL observations in the optical, UV and X-ray regime, to be conducted simultaneous to very high energy observations with the H.E.S.S. experiment, to study the emission processes. Simultaneous observations are crucial, since BL Lac objects are variable at all wavebands. I have analysed the MWL observations and conducted detailed variability and spectral studies in each wavelength range. The different kind of absorption at each wavelength as well as the influence of the host galaxy of the AGN has been considered to obtain the intrinsic jet spectrum. I have then applied the commonly used theoretical jet model, the SSC model, to the SED. I conducted a MWL campaign on a BL Lac object with the softest TeV spectrum, PKS 2005-489, during which it was observed in a very bright X-ray state. The good spectral coverage of the emission peaks allowed a detailed study of the SSC model. The extreme BL Lac object 1ES 0229+200 exhibits a hard intrinsic TeV spectrum. With my MWL campaign I found a clear cut-off in the optical range and therefore a high minimum Lorentz factor is needed to

  3. Single Mode Fiber Optic Transceiver Using Short Wavelength Active Devices In Long Wavelength Fiber

    Science.gov (United States)

    Gillham, Frederick J.; Campbell, Daniel R.; Corke, Michael; Stowe, David W.

    1990-01-01

    Presently, single mode optical fiber technology is being utilized in systems to supply telephone service to the subscriber. However, in an attempt to be competitive with copper based systems, there are many development programs underway to determine the most cost effective solution while still providing a service that will either satisfy or be upgradeable to satisfy the demands of the consumer for the next 10 to 20 years. One such approach is to combine low cost laser transmitters and silicon receivers, which have been developed for the "compact disc" industry, with fiber that operates in the single mode regime at 1300 nm. In this paper, an optical transceiver will be presented, consisting of a compact disc laser, a silicon detector and a single mode coupler at 1300 nm. A possible system layout is presented which operates at 780 nm bi-directionally for POTS and upgradeable to 1300 nm for video services. There are several important design criteria that have to be considered in the development of such a system which will be addressed. These include: 1. Optimization of coupled power from laser to fiber while maintaining stable launched conditions over a wide range of environmental conditions. 2. Consideration of the multimode operation of the 1300 nm single mode fiber while operating in the 780 nm wavelength region. 3. Development of a low cost pseudo-wavelength division multiplexer for 1300 nm single mode/780 nm multimode operation and a low cost dual mode 50/50, 780 nm splitter using 1300 nm fiber. Details will be given of the design criteria and solution in terms of optimized design. Results of the performance of several prototype devices will be given with indications of the merits of this approach and where further development effort should be applied.

  4. Free-space wavelength-multiplexed optical scanner.

    Science.gov (United States)

    Yaqoob, Z; Rizvi, A A; Riza, N A

    2001-12-10

    A wavelength-multiplexed optical scanning scheme is proposed for deflecting a free-space optical beam by selection of the wavelength of the light incident on a wavelength-dispersive optical element. With fast tunable lasers or optical filters, this scanner features microsecond domain scan setting speeds and large- diameter apertures of several centimeters or more for subdegree angular scans. Analysis performed indicates an optimum scan range for a given diffraction order and grating period. Limitations include beam-spreading effects based on the varying scanner aperture sizes and the instantaneous information bandwidth of the data-carrying laser beam.

  5. Rational choices for the wavelengths of a two color interferometer

    International Nuclear Information System (INIS)

    Jobes, F.C.

    1995-07-01

    If in a two color interferometer for plasma density measurements, the two wavelengths are chosen to have a ratio that is a rational number, and if the signals from each of the wavelengths are multiplied in frequency by the appropriate integer of the rational number and then heterodyned together, the resultant signal will have all effects of component motion nulled out. A phase measurement of this signal will have only plasma density information in it. With CO 2 lasers, it is possible to find suitable wavelength pairs which are close enough to rational numbers to produce an improvement of about 100 in density resolution, compared to standard two color interferometers

  6. Radiative flux calculations at UV and visible wavelengths

    International Nuclear Information System (INIS)

    Grossman, A.S.; Grant, K.E.; Wuebbles, D.J.

    1993-10-01

    A radiative transfer model to calculate the short wavelength fluxes at altitudes between 0 and 80 km has been developed at LLNL. The wavelength range extends from 175--735 nm. This spectral range covers the UV-B wavelength region, 250--350 nm, with sufficient resolution to allow comparison of UV-B measurements with theoretical predictions. Validation studies for the model have been made for both UV-B ground radiation calculations and tropospheric solar radiative forcing calculations for various ozone distributions. These studies indicate that the model produces results which agree well with respect to existing UV calculations from other published models

  7. Photoluminescence wavelength variation of monolayer MoS2 by oxygen plasma treatment

    International Nuclear Information System (INIS)

    Kim, Min Su; Nam, Giwoong; Park, Seki; Kim, Hyun; Han, Gang Hee; Lee, Jubok; Dhakal, Krishna P.; Leem, Jae-Young; Lee, Young Hee; Kim, Jeongyong

    2015-01-01

    We performed nanoscale confocal photoluminescence (PL), Raman, and absorption spectral imaging measurements to investigate the optical and structural properties of molybdenum disulfide (MoS 2 ) monolayers synthesized by chemical vapor deposition method and subjected to oxygen plasma treatment for 10 to 120 s under high vacuum (1.3 × 10 −3 Pa). Oxygen plasma treatment induced red shifts of ~ 20 nm in the PL emission peaks corresponding to A and B excitons. Similarly, the peak positions corresponding to A and B excitons of the absorption spectra were red-shifted following oxygen plasma treatment. Based on the confocal PL, absorption, and Raman microscopy results, we suggest that the red-shifting of the A and B exciton peaks originated from shallow defect states generated by oxygen plasma treatment. - Highlights: • Effects of oxygen plasma on optical properties of monolayer MoS 2 were investigated. • Confocal photoluminescence, Raman, and absorption spectral maps are presented. • Wavelength tuning up to ~ 20 nm for the peak emission wavelength was achieved

  8. Photoluminescence wavelength variation of monolayer MoS{sub 2} by oxygen plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Su [Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Nam, Giwoong [Department of Nanoscience & Engineering, Inje University, Gimhae 621-749 (Korea, Republic of); Park, Seki; Kim, Hyun [Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Han, Gang Hee [Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Jubok; Dhakal, Krishna P. [Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Leem, Jae-Young [Department of Nanoscience & Engineering, Inje University, Gimhae 621-749 (Korea, Republic of); Lee, Young Hee [Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Department of Physics, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Jeongyong, E-mail: j.kim@skku.edu [Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2015-09-01

    We performed nanoscale confocal photoluminescence (PL), Raman, and absorption spectral imaging measurements to investigate the optical and structural properties of molybdenum disulfide (MoS{sub 2}) monolayers synthesized by chemical vapor deposition method and subjected to oxygen plasma treatment for 10 to 120 s under high vacuum (1.3 × 10{sup −3} Pa). Oxygen plasma treatment induced red shifts of ~ 20 nm in the PL emission peaks corresponding to A and B excitons. Similarly, the peak positions corresponding to A and B excitons of the absorption spectra were red-shifted following oxygen plasma treatment. Based on the confocal PL, absorption, and Raman microscopy results, we suggest that the red-shifting of the A and B exciton peaks originated from shallow defect states generated by oxygen plasma treatment. - Highlights: • Effects of oxygen plasma on optical properties of monolayer MoS{sub 2} were investigated. • Confocal photoluminescence, Raman, and absorption spectral maps are presented. • Wavelength tuning up to ~ 20 nm for the peak emission wavelength was achieved.

  9. Many faces of compact objects: distance, optical extinction and multi-wavelength behaviour

    International Nuclear Information System (INIS)

    Corbel, Stephane

    1999-01-01

    This thesis is devoted to a multi-wavelength study of accretion-ejection phenomena around compact stars (black holes and neutron stars). The first part of this manuscript describes problems related to the determination of the distance and the optical extinction to compact objects - fundamental parameters for the evaluation of the energy budget of these systems. To this end, the structure and the dynamics of the Galaxy are studied by observations of the atomic and molecular gas along the line of sight to compact stars. This method leads to the first evaluation of the distance to two Soft Gamma Repeaters: SGR 1806-20 and SGR 1627-41. We then draw some conclusions on the nature of these sources of recurrent gamma-ray bursts. The above method is then applied to two X-ray binaries: Cir X-1 and GX 339-4. In the second part of this thesis, we present a multi-wavelength study of the Galactic black hole candidate GX 339-4. We first discuss the characteristics of the radio emission from GX 339-4. In 1998, GX 339-4 underwent a transition to a soft-high X-ray state and observations in three wavelength regimes (radio, soft and hard X-rays) revealed new patterns of behaviour. This allowed us to constrain the region of origin of the radio emission (a compact jet) in GX 339-4 and allowed a better understanding of the physical coupling between accretion and ejection in GX 339-4. An analogy with the black hole candidate Cyg X-1 is then presented. Finally, these results are discussed in the context of micro-quasars and active galactic nuclei in order to gain a deeper insight into the accretion-ejection coupling around compact objects. (author) [fr

  10. Multi-wavelength Characterization of Brown and Black Carbon from Filter Samples

    Science.gov (United States)

    Johnson, M. M.; Yatavelli, R. L. N.; Chen, L. W. A. A.; Gyawali, M. S.; Arnott, W. P.; Wang, X.; Chakrabarty, R. K.; Moosmüller, H.; Watson, J. G.; Chow, J. C.

    2014-12-01

    Particulate matter (PM) scatters and absorbs solar radiation and thereby affects visibility, the Earth's radiation balance, and properties and lifetimes of clouds. Understanding the radiative forcing (RF) of PM is essential to reducing the uncertainty in total anthropogenic and natural RF. Many instruments that measure light absorption coefficients (βabs [λ], Mm-1) of PM have used light at near-infrared (NIR; e.g., 880 nm) or red (e.g., 633 nm) wavelengths. Measuring βabs over a wider wavelength range, especially including the ultraviolet (UV) and visible, allows for contributions from black carbon (BC), brown carbon (BrC), and mineral dust (MD) to be differentiated. This will help to determine PM RF and its emission sources. In this study, source and ambient samples collected on Teflon-membrane and quartz-fiber filters are used to characterize and develop a multi-wavelength (250 - 1000 nm) filter-based measurement method of PM light absorption. A commercially available UV-visible spectrometer coupled with an integrating sphere is used for quantifying diffuse reflectance and transmittance of filter samples, from which βabs and absorption Ǻngström exponents (AAE) of the PM deposits are determined. The filter-based light absorption measurements of laboratory generated soot and biomass burning aerosol are compared to 3-wavelength photoacoustic absorption measurements to evaluate filter media and loading effects. Calibration factors are developed to account for differences between filter types (Teflon-membrane vs. quartz-fiber), and between filters and in situ photoacoustic absorption values. Application of multi-spectral absorption measurements to existing archived filters, including specific source samples (e.g. diesel and gasoline engines, biomass burning, dust), will also be discussed.

  11. Primary explosives

    Energy Technology Data Exchange (ETDEWEB)

    Matyas, Robert; Pachman, Jiri [Pardubice Univ. (Czech Republic). Faculty of Chemical Technology

    2013-06-01

    The first chapter provides background such as the basics of initiation and differences between requirements on primary explosives used in detonators and igniters. The authors then clarify the influence of physical characteristics on explosive properties, focusing on those properties required for primary explosives. Furthermore, the issue of sensitivity is discussed. All the chapters on particular groups of primary explosives are structured in the same way, including introduction, physical and chemical properties, explosive properties, preparation and documented use.

  12. Primary fibromyalgia

    DEFF Research Database (Denmark)

    Jacobsen, S; Jensen, L T; Foldager, M

    1990-01-01

    Serum concentrations of procollagen type III aminoterminal peptide have previously been reported to be low in some patients with primary fibromyalgia and the aim of this study was to determine if such patients differ clinically from primary fibromyalgia patients with normal levels of procollagen...... type III aminoterminal peptide. Subjective symptoms, tender points and dynamic muscle strength in 45 women with primary fibromyalgia were related to serum concentrations of procollagen type III aminoterminal peptide. Patients with low serum concentrations of procollagen type III aminoterminal peptide...... concentrations of procollagen type III aminoterminal peptide of primary fibromyalgia patients are connected to the disease impact....

  13. Effect of wavelength shifters on water Cherenkov detectors

    Energy Technology Data Exchange (ETDEWEB)

    Badino, G; Galeotti, P; Periale, L; Saavedra, O; Turtelli, A [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Turin Univ. (Italy). Ist. di Fisica Generale)

    1981-06-15

    We report the results of a test showing that concentrations of approx. equal to 2 mg/l of wavelength shifter in water give almost the maximum efficiency of detection without losing the directionality of Cherenkov light.

  14. Two-wavelength HeNe laser interferometer

    International Nuclear Information System (INIS)

    Granneman, E.H.A.

    1981-01-01

    This paper presents an interferometer set-up in which two wavelengths are used simultaneously. This enables one to determine separately the phase shifts caused by changes in plasma density and by mechanical vibrations of the interferometer structure

  15. Multi-wavelength Ocean Profiling and Atmospheric Lidar

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to build and demonstrate the world's first multi-wavelength ocean-profiling high spectral resolution lidar (HSRL). The lidar will provide profiles of...

  16. Isoplanatic patch of the human eye for arbitrary wavelengths

    Science.gov (United States)

    Han, Guoqing; Cao, Zhaoliang; Mu, Quanquan; Wang, Yukun; Li, Dayu; Wang, Shaoxin; Xu, Zihao; Wu, Daosheng; Hu, Lifa; Xuan, Li

    2018-03-01

    The isoplanatic patch of the human eye is a key parameter for the adaptive optics system (AOS) designed for retinal imaging. The field of view (FOV) usually sets to the same size as the isoplanatic patch to obtain high resolution images. However, it has only been measured at a specific wavelength. Here we investigate the wavelength dependence of this important parameter. An optical setup is initially designed and established in a laboratory to measure the isoplanatic patch at various wavelengths (655 nm, 730 nm and 808 nm). We established the Navarro wide-angle eye model in Zemax software to further validate our results, which suggested high consistency between the two. The isoplanatic patch as a function of wavelength was obtained within the range of visible to near-infrared, which can be expressed as: θ=0.0028 λ - 0 . 74. This work is beneficial for the AOS design for retinal imaging.

  17. Portable Long-Wavelength Infrared Camera for Civilian Application

    Science.gov (United States)

    Gunapala, S. D.; Krabach, T. N.; Bandara, S. V.; Liu, J. K.

    1997-01-01

    In this paper, we discuss the performance of this portable long-wavelength infrared camera in quantum efficiency, NEAT, minimum resolvable temperature differnce (MRTD), uniformity, etc. and its application in science, medicine and defense.

  18. Infrared presensitization photography at deuterium fluoride laser wavelengths

    International Nuclear Information System (INIS)

    Geary, J.M.; Ross, K.; Suter, K.

    1989-01-01

    Near-field irradiance distributions of a deuterium flouride laser system are obtained using infrared presensitization photography. This represents the shortest wavelength region to employ this technique thus far

  19. Valuing spectrum at mm wavelengths for cellular networks

    OpenAIRE

    Shaw, B. A.; Beltrán, H. F.; Sowerby, K. W.

    2017-01-01

    This paper investigates the economic value of spectrum at mm wavelengths. The analysis uses four techniques to value spectrum, namely a benchmarking comparison, a discounted cash flow analysis, a real options approach and a deprival method. The methods to calculate spectrum value presented in this paper can be used for any spectrum band and in any country. However, to determine the value of mm wavelengths for cellular networks, we have used data from New Zealand, specifically for the existing...

  20. A MULTI-WAVELENGTH STUDY OF THE STAR-FORMING CORE AHEAD OF HH 80N

    International Nuclear Information System (INIS)

    Masque, Josep M.; Estalella, Robert; Osorio, Mayra; Anglada, Guillem; Girart, Josep M.; Garay, Guido; Calvet, Nuria; Beltran, Maria T.

    2011-01-01

    We present observations of continuum emission in the mid-infrared to millimeter wavelength range, complemented with ammonia observations, of the dense core ahead of the radio Herbig-Haro (HH) object HH 80N, found in the GGD 27 region. The continuum emission in all the observed bands peaks at the same position, consistent with the presence of an embedded object, HH 80N-IRS1, within the core. The distribution of the Very Large Array ammonia emission is well correlated with that of the dust, suggesting that photochemical effects caused by the nearby HH object do not play an important role in shaping this particular molecular emission. In order to unveil the nature of HH 80N-IRS1, we analyzed the continuum data of this source, using self-consistent models of protostellar collapse. We find that a young protostar surrounded by a slowly rotating collapsing envelope of radius ∼0.08 pc and 20 M sun plus a circumstellar disk of radius ∼300 AU and 0.6 M sun provide a good fit to the observed spectral energy distribution and to the maps at 350 μm, 1.2 mm, and 3.5 mm of HH 80N-IRS1. Besides, the Atacama Pathfinder Experiment and Plateau de Bure Interferometer continuum maps at 350 μm and 3.5 mm, respectively, reveal additional clumps in the continuum emission. Given the modeling results and the observed morphology of the emission, we propose a scenario consisting of a central embedded Class 0 object, HH 80N-IRS1, with the rest of the material of the HH 80N core possibly undergoing fragmentation that may lead to the formation of several protostars.

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

    Science.gov (United States)

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

    2012-10-01

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

  2. Extending the depth of field with chromatic aberration for dual-wavelength iris imaging.

    Science.gov (United States)

    Fitzgerald, Niamh M; Dainty, Christopher; Goncharov, Alexander V

    2017-12-11

    We propose a method of extending the depth of field to twice that achievable by conventional lenses for the purpose of a low cost iris recognition front-facing camera in mobile phones. By introducing intrinsic primary chromatic aberration in the lens, the depth of field is doubled by means of dual wavelength illumination. The lens parameters (radius of curvature, optical power) can be found analytically by using paraxial raytracing. The effective range of distances covered increases with dispersion of the glass chosen and with larger distance for the near object point.

  3. Optical cross-connect circuit using hitless wavelength selective switch.

    Science.gov (United States)

    Goebuchi, Yuta; Hisada, Masahiko; Kato, Tomoyuki; Kokubun, Yasuo

    2008-01-21

    We have proposed and demonstrated the basic elements of a full matrix optical switching circuit (cross-connect circuit) using a hitless wavelength selective switch (WSS). The cross-connect circuits are made of a multi-wavelength channel selective switch consisting of cascaded hitless WSSs, and a multi-port switch. These switching elements are realized through the individual Thermo-Optic (TO) tuning of a series-coupled microring resonator, and can switch arbitrary wavelength channels without blocking other wavelength channels during tuning. We demonstrate a four wavelength selective switch using a parallel topology of double series coupled microring resonators and a three wavelength selective switch using a parallel topology of quadruple series coupled microring resonators. Since the spectrum shape of quadruple series coupled microring is much more box-like than the double series, a high extinction ratio of 39.0-46.6 dB and low switching cross talk of 19.3-24.5 dB were achieved.

  4. Impact of beacon wavelength on phase-compensation performance

    Science.gov (United States)

    Enterline, Allison A.; Spencer, Mark F.; Burrell, Derek J.; Brennan, Terry J.

    2017-09-01

    This study evaluates the effects of beacon-wavelength mismatch on phase-compensation performance. In general, beacon-wavelength mismatch occurs at the system level because the beacon-illuminator laser (BIL) and high-energy laser (HEL) are often at different wavelengths. Such is the case, for example, when using an aperture sharing element to isolate the beam-control sensor suite from the blinding nature of the HEL. With that said, this study uses the WavePlex Toolbox in MATLAB® to model ideal spherical wave propagation through various atmospheric-turbulence conditions. To quantify phase-compensation performance, we also model a nominal adaptive-optics (AO) system. We achieve correction from a Shack-Hartmann wavefront sensor and continuous-face-sheet deformable mirror using a least-squares phase reconstruction algorithm in the Fried geometry and a leaky integrator control law. To this end, we plot the power in the bucket metric as a function of BIL-HEL wavelength difference. Our initial results show that positive BIL-HEL wavelength differences achieve better phase compensation performance compared to negative BIL-HEL wavelength differences (i.e., red BILs outperform blue BILs). This outcome is consistent with past results.

  5. Wavelength calibration of an imaging spectrometer based on Savart interferometer

    Science.gov (United States)

    Li, Qiwei; Zhang, Chunmin; Yan, Tingyu; Quan, Naicheng; Wei, Yutong; Tong, Cuncun

    2017-09-01

    The basic principle of Fourier-transform imaging spectrometer (FTIS) based on Savart interferometer is outlined. The un-identical distribution of the optical path difference which leads to the wavelength drift of each row of the interferogram is analyzed. Two typical methods for wavelength calibration of the presented system are described. The first method unifies different spectral intervals and maximum spectral frequencies of each row by a reference monochromatic light with known wavelength, and the dispersion compensation of Savart interferometer is also involved. The second approach is based on the least square fitting which builds the functional relation between recovered wavelength, row number and calibrated wavelength by concise equations. The effectiveness of the two methods is experimentally demonstrated with monochromatic lights and mixed light source across the detecting band of the system, and the results indicate that the first method has higher precision and the mean root-mean-square error of the recovered wavelengths is significantly reduced from 19.896 nm to 1.353 nm, while the second method is more convenient to implement and also has good precision of 2.709 nm.

  6. Phosphorus-free mode-locked semiconductor laser with emission wavelength 1550 nm

    Science.gov (United States)

    Kolodeznyi, E. S.; Novikov, I. I.; Babichev, A. V.; Kurochkin, A. S.; Gladyshev, A. G.; Karachinsky, L. Ya; Gadzhiev, I. M.; Buyalo, M. S.; Usikova, A. A.; Ilynskaya, N. D.; Bougrov, V. E.; Egorov, A. Yu

    2017-11-01

    We have fabricated passive mode-locked laser diodes based on strained InGaAlAs/InGaAs/InP heterostructures with crystal lattice mismatch parameter of +1.0 % between quantum well and barrier. The laser with temperature stabilization at 18 °C was demonstrated 10.027 GHz optical pulse repetition rate with 6 ps pulse duration time. Timing jitter of optical pulses in mode-locked regime was 0.145 ps.

  7. Electronic emission and electron guns

    International Nuclear Information System (INIS)

    Roy, Amitava

    2010-01-01

    This paper reviews the process of electron emission from metal surface. Although electrons move freely in conductors like metals, they normally do not leave the metal without some manipulation. In fact, heating and bombardment are the two primary ways in which electrons are emitted through the use of a heating element behind the cathode (termed thermionic emission) or as a result of bombardment with a beam of electrons, ions, or metastable atoms (termed secondary emission). Another important emission mechanism called Explosive Electron Emission (EEE) is also often used in various High Voltage Pulse Power Systems to generate very high current (few hundreds of kA) pulsed electron beams. The electron gun is the device in that it shoots off a continuous (or pulsed) stream of electrons. A brief idea about the evolution of the electron gun components and their basis of functioning are also discussed. (author)

  8. Comparison of 2- and 4-wavelength methods for the optical detection of sentinel lymph node

    Science.gov (United States)

    Tellier, F.; Simon, H.; Blé, F. X.; Ravelo, R.; Chabrier, R.; Steibel, J.; Rodier, J. F.; Poulet, P.

    2011-07-01

    Sentinel lymph node biopsy is the gold standard method to detect a metastatic invasion from the primary breast cancer. This method can avoid patients to be submitted to full axillary chain dissection. In this study we present and compare two near-infrared optical probes for the sentinel lymph node detection, based on the recording of scattered photons. The two setups were developed to improve the detection of the dye injected in clinical routine: the Patent Blue V dye. Herein, we present results regarding clinical ex-vivo detection of sentinel lymph node after different volume injections. We have previously published results obtained with a two-wavelength probe on phantom and animal models. However this first generation device did not completely account for the optical absorption variations from biological tissue. Thus, a second generation probe has been equipped with four wavelengths. The dye concentration computation is then more robust to measurement and tissue property fluctuations. The detection threshold of the second setup was estimated at 8.10-3μmol/L, which is about 37 times lower than the eye visibility threshold. We present here the preliminary results and demonstrate the advantages of using four wavelengths compared to two on phantom suspensions simulating the optical properties of breast tissues.

  9. Thermoluminescence emission spectra and optical bleaching of oligoclase

    International Nuclear Information System (INIS)

    Bos, A.J.J.; Piters, T.M.; Ypma, P.J.

    1994-01-01

    Thermoluminescence (TL) spectra of oligoclase samples have been recorded in the temperature range from 300 to 700 K and the wavelength range from 300 to 850 nm. Like other feldspars, oligoclase produces blue (peaking at 460 nm) and red (peaking at 765 nm) emission bands. The maximum of the red emission occurs 20 K lower than that of the blue band. Optical bleaching was performed at wavelengths varying from 360 to 800 nm. Bleaching of artificially irradiated oligoclase causes a decrease of the TL signal. The bleaching efficiency increases with decreasing wavelength. Bleaching does not only influence the height of the glow curve but also the shape. An interesting observation is that the ratio of the blue and red band intensities is not affected by a bleaching procedure. No evidence has been found that bleaching influences the shape of the emission spectra. The correlation between the blue and red bands is discussed. (Author)

  10. Broadband transmission grating spectrometer for measuring the emission spectrum of EUV sources

    NARCIS (Netherlands)

    Bayraktar, Muharrem; Bastiaens, Hubertus M.J.; Bruineman, Caspar; Vratzov, Boris; Bijkerk, Frederik

    2016-01-01

    Extreme ultraviolet (EUV) light sources and their optimization for emission within a narrow wavelength band are essential in applications such as photolithography. Most light sources however also emit radiation outside this wavelength band and have a spectrum extending up to deep ultraviolet (DUV)

  11. Coronal magnetic fields inferred from IR wavelength and comparison with EUV observations

    Directory of Open Access Journals (Sweden)

    Y. Liu

    2009-07-01

    Full Text Available Spectropolarimetry using IR wavelength of 1075 nm has been proved to be a powerful tool for directly mapping solar coronal magnetic fields including transverse component directions and line-of-sight component intensities. Solar tomography, or stereoscopy based on EUV observations, can supply 3-D information for some magnetic field lines in bright EUV loops. In a previous paper \\citep{liu08} the locations of the IR emission sources in the 3-D coordinate system were inferred from the comparison between the polarization data and the potential-field-source-surface (PFSS model, for one of five west limb regions in the corona (Lin et al., 2004. The paper shows that the region with the loop system in the active region over the photospheric area with strong magnetic field intensity is the region with a dominant contribution to the observed Stokes signals. So, the inversion of the measured Stokes parameters could be done assuming that most of the signals come from a relatively thin layer over the area with a large photospheric magnetic field strength. Here, the five limb coronal regions are studied together in order to study the spatial correlation between the bright EUV loop features and the inferred IR emission sources. It is found that, for the coronal regions above the stronger photospheric magnetic fields, the locations of the IR emission sources are closer to or more consistent with the bright EUV loop locations than those above weaker photospheric fields. This result suggests that the structures of the coronal magnetic fields observed at IR and EUV wavelengths may be different when weak magnetic fields present there.

  12. THE CHROMOSPHERIC SOLAR LIMB BRIGHTENING AT RADIO, MILLIMETER, SUB-MILLIMETER, AND INFRARED WAVELENGTHS

    Energy Technology Data Exchange (ETDEWEB)

    De la Luz, V. [Conacyt—SCiESMEX, Instituto de Geofísica, Unidad Michoacán, Universidad Nacional Autónoma de México, Morelia, Michoacán, 58190, México (Mexico)

    2016-07-10

    Observations of the emission at radio, millimeter, sub-millimeter, and infrared wavelengths in the center of the solar disk validate the autoconsistence of semi-empirical models of the chromosphere. Theoretically, these models must reproduce the emission at the solar limb. In this work, we tested both the VALC and C7 semi-empirical models by computing their emission spectrum in the frequency range from 2 GHz to 10 THz at solar limb altitudes. We calculate the Sun's theoretical radii as well as their limb brightening. Non-local thermodynamic equilibrium was computed for hydrogen, electron density, and H{sup −}. In order to solve the radiative transfer equation, a three-dimensional (3D) geometry was employed to determine the ray paths, and Bremsstrahlung, H{sup −}, and inverse Bremsstrahlung opacity sources were integrated in the optical depth. We compared the computed solar radii with high-resolution observations at the limb obtained by Clark. We found that there are differences between the observed and computed solar radii of 12,000 km at 20 GHz, 5000 km at 100 GHz, and 1000 km at 3 THz for both semi-empirical models. A difference of 8000 km in the solar radii was found when comparing our results against the heights obtained from H α observations of spicules-off at the solar limb. We conclude that the solar radii cannot be reproduced by VALC and C7 semi-empirical models at radio—infrared wavelengths. Therefore, the structures in the high chromosphere provide a better measurement of the solar radii and their limb brightening as shown in previous investigations.

  13. THE CHROMOSPHERIC SOLAR LIMB BRIGHTENING AT RADIO, MILLIMETER, SUB-MILLIMETER, AND INFRARED WAVELENGTHS

    International Nuclear Information System (INIS)

    De la Luz, V.

    2016-01-01

    Observations of the emission at radio, millimeter, sub-millimeter, and infrared wavelengths in the center of the solar disk validate the autoconsistence of semi-empirical models of the chromosphere. Theoretically, these models must reproduce the emission at the solar limb. In this work, we tested both the VALC and C7 semi-empirical models by computing their emission spectrum in the frequency range from 2 GHz to 10 THz at solar limb altitudes. We calculate the Sun's theoretical radii as well as their limb brightening. Non-local thermodynamic equilibrium was computed for hydrogen, electron density, and H − . In order to solve the radiative transfer equation, a three-dimensional (3D) geometry was employed to determine the ray paths, and Bremsstrahlung, H − , and inverse Bremsstrahlung opacity sources were integrated in the optical depth. We compared the computed solar radii with high-resolution observations at the limb obtained by Clark. We found that there are differences between the observed and computed solar radii of 12,000 km at 20 GHz, 5000 km at 100 GHz, and 1000 km at 3 THz for both semi-empirical models. A difference of 8000 km in the solar radii was found when comparing our results against the heights obtained from H α observations of spicules-off at the solar limb. We conclude that the solar radii cannot be reproduced by VALC and C7 semi-empirical models at radio—infrared wavelengths. Therefore, the structures in the high chromosphere provide a better measurement of the solar radii and their limb brightening as shown in previous investigations.

  14. Short-wavelength luminescence in Ho{sup 3+}-doped KGd(WO{sub 4}){sub 2} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Malinowski, M., E-mail: m.malinowski@elka.pw.edu.p [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Kaczkan, M.; Stopinski, S.; Piramidowicz, R. [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Majchrowski, A. [Institute of Applied Physics, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland)

    2009-12-15

    Emissions from the high-lying excited states, energy transfer and upconversion processes are investigated in Ho{sup 3+}-activated KGd(WO{sub 4}){sub 2} crystal. The spectral assignment based on time-resolved emission spectra allowed to identify various near ultra-violet (UV), blue and green emissions starting from the excited {sup 3}H{sub 5}, {sup 5}G{sub 4}, {sup 5}G{sub 5}, {sup 5}F{sub 3} and {sup 5}S{sub 2} levels. The temporal behavior of these transitions after pulsed excitation was analyzed as a function of temperature and holmium ions concentration. The shortening and nonexponentiality of the decays, observed with increasing activator concentrations, indicated cross-relaxation (CR) among the Ho{sup 3+} ions. Cross-relaxation rates were experimentally determined as a function of activator concentration and used to evaluate the values of the nearest-neighbor trapping rates X{sub 01} and to model the decays. It was observed that KGW, despite higher than in YAG maximum phonon energy of about 900 cm{sup -1}, is more efficient short-wavelength emitter than YAG. Examples of the excited-state absorption (ESA) and energy transfer (ET) mechanisms responsible for the upconverted, short-wavelength emissions were identified by analyzing fluorescence dynamics and possible energy resonances.

  15. SG1120-1202: Mass-quenching as Tracked by UV Emission in the Group Environment at z=0.37

    Science.gov (United States)

    Monroe, Jonathan T.; Tran, Kim-Vy H.; Gonzalez, Anthony H.

    2017-02-01

    We use the Hubble Space Telescope to obtain WFC3/F390W imaging of the supergroup SG1120-1202 at z=0.37, mapping the UV emission of 138 spectroscopically confirmed members. We measure total (F390W-F814W) colors and visually classify the UV morphology of individual galaxies as “clumpy” or “smooth.” Approximately 30% of the members have pockets of UV emission (clumpy) and we identify for the first time in the group environment galaxies with UV morphologies similar to the “jellyfish” galaxies observed in massive clusters. We stack the clumpy UV members and measure a shallow internal color gradient, which indicates that unobscured star formation is occurring throughout these galaxies. We also stack the four galaxy groups and measure a strong trend of decreasing UV emission with decreasing projected group distance ({R}{proj}). We find that the strong correlation between decreasing UV emission and increasing stellar mass can fully account for the observed trend in (F390W-F814W)-{R}{proj}, I.e., mass-quenching is the dominant mechanism for extinguishing UV emission in group galaxies. Our extensive multi-wavelength analysis of SG1120-1202 indicates that stellar mass is the primary predictor of UV emission, but that the increasing fraction of massive (red/smooth) galaxies at {R}{proj} ≲ 2 R 200 and existence of jellyfish candidates is due to the group environment.

  16. Acoustic emission

    International Nuclear Information System (INIS)

    Straus, A.; Lopez Pumarega, M.I.; Di Gaetano, J.O.; D'Atellis, C.E.; Ruzzante, J.E.

    1990-01-01

    This paper is related to our activities on acoustic emission (A.E.). The work is made with different materials: metals and fibre reinforced plastics. At present, acoustic emission transducers are being developed for low and high temperature. A test to detect electrical discharges in electrical transformers was performed. Our experience in industrial tests to detect cracks or failures in tanks or tubes is also described. The use of A.E. for leak detection is considered. Works on pattern recognition of A.E. signals are also being performed. (Author)

  17. All-optical 40 Gbit/s compact integrated interferometric wavelength converter

    DEFF Research Database (Denmark)

    Jørgensen, Carsten; Danielsen, Søren Lykke; Hansen, Peter Bukhave

    1997-01-01

    An interferometric Michelson wavelength converter is presented that combines a speed-optimized semiconductor optical amplifier technology with the benefits of the integrated interferometer showing 40-Gbit/s wavelength conversion. The optimized wavelength converter demonstrates noninverted converted...

  18. Primary productivity

    Digital Repository Service at National Institute of Oceanography (India)

    Verlecar, X.N.; Parulekar, A.H.

    Photosynthetic production in the oceans in relation to light, nutrients and mixing processes is discussed. Primary productivity in the estuarine region is reported to be high in comparison to coastal and oceanic waters. Upwelling phenomenon...

  19. Primary Hyperparathyroidism

    Science.gov (United States)

    ... Neoplasia Type 1 Thyroid Disease & Pregnancy Primary Hyperparathyroidism Prolactinoma National Hormone and Pituitary Program (NHPP): Information for ... qualified health care provider nearby. Eating, Diet, and Nutrition Eating, diet, and nutrition have not been shown ...

  20. Primary Myelofibrosis

    Science.gov (United States)

    ... attack is higher. Patients also have an increased risk of acute myeloid leukemia or primary myelofibrosis . Symptoms of polycythemia vera include headaches and a feeling of fullness below the ribs on the left ...

  1. A Multi-Wavelength IR Laser for Space Applications

    Science.gov (United States)

    Li, Steven X.; Yu, Anthony W.; Sun, Xiaoli; Fahey, Molly E.; Numata, Kenji; Krainak, Michael A.

    2017-01-01

    We present a laser technology development with space flight heritage to generate laser wavelengths in the near- to mid-infrared (NIR to MIR) for space lidar applications. Integrating an optical parametric crystal to the LOLA (Lunar Orbiter Laser Altimeter) laser transmitter design affords selective laser wavelengths from NIR to MIR that are not easily obtainable from traditional diode pumped solid-state lasers. By replacing the output coupler of the LOLA laser with a properly designed parametric crystal, we successfully demonstrated a monolithic intra-cavity optical parametric oscillator (iOPO) laser based on all high technology readiness level (TRL) subsystems and components. Several desired wavelengths have been generated including 2.1 microns, 2.7 microns and 3.4 microns. This laser can also be used in trace-gas remote sensing, as many molecules possess their unique vibrational transitions in NIR to MIR wavelength region, as well as in time-of-flight mass spectrometer where desorption of samples using MIR laser wavelengths have been successfully demonstrated.

  2. Multi-Wavelength Photomagnetic Imaging for Oral Cancer

    Science.gov (United States)

    Marks, Michael

    In this study, a multi-wavelength Photomagnetic Imaging (PMI) system is developed and evaluated with experimental studies.. PMI measures temperature increases in samples illuminated by near-infrared light sources using magnetic resonance thermometry. A multiphysics solver combining light and heat transfer models the spatiotemporal distribution of the temperature change. The PMI system develop in this work uses three lasers of varying wavelength (785 nm, 808 nm, 860 nm) to heat the sample. By using multiple wavelengths, we enable the PMI system to quantify the relative concentrations of optical contrast in turbid media and monitor their distribution, at a higher resolution than conventional diffuse optical imaging. The data collected from agarose phantoms with multiple embedded contrast agents designed to simulate the optical properties of oxy- and deoxy-hemoglobin is presented. The reconstructed images demonstrate that multi-wavelength PMI can resolve this complex inclusion structure with high resolution and recover the concentration of each contrast agent with high quantitative accuracy. The modified multi-wavelength PMI system operates under the maximum skin exposure limits defined by the American National Standards Institute, to enable future clinical applications.

  3. Choice of the laser wavelength for a herpetic keratitis treatment

    Science.gov (United States)

    Razhev, Alexander M.; Bagayev, Sergei N.; Chernikh, Valery V.; Kargapoltsev, Evgeny S.; Trunov, Alexander; Zhupikov, Andrey A.

    2002-06-01

    For the first time the effect of the UV laser radiation to human eye cornea with herpetic keratitis was experimentally investigated. In experiments the UV radiation of ArF (193 nm), KrCl (223 nm), KrF (248 nm) excimer lasers were used. Optimal laser radiation parameters for the treatment of the herpetic keratitis were determined. The immuno-biochemical investigations were carried out and the results of clinical trials are presented. The maximum ablation rate was obtained for the 248 nm radiation wavelength. The process of healing was successful but in some cases the haze on the surface of the cornea was observed. When used the 193 nm radiation wavelength the corneal surface was clear without any hazes but the epithelization process was slower than for 248 nm wavelength and in some cases the relapse was occurred. The best results for herpetic keratitis treatment have been achieved by utilizing the 223 nm radiation wavelength of the KrCl excimer laser. The use of the 223 nm radiation wavelength allows treating the herpetic keratitis with low traumatic process of ablation and provides high quality of corneal surface.

  4. Wavelength calibration of imaging spectrometer using atmospheric absorption features

    Science.gov (United States)

    Zhou, Jiankang; Chen, Yuheng; Chen, Xinhua; Ji, Yiqun; Shen, Weimin

    2012-11-01

    Imaging spectrometer is a promising remote sensing instrument widely used in many filed, such as hazard forecasting, environmental monitoring and so on. The reliability of the spectral data is the determination to the scientific communities. The wavelength position at the focal plane of the imaging spectrometer will change as the pressure and temperature vary, or the mechanical vibration. It is difficult for the onboard calibration instrument itself to keep the spectrum reference accuracy and it also occupies weight and the volume of the remote sensing platform. Because the spectral images suffer from the atmospheric effects, the carbon oxide, water vapor, oxygen and solar Fraunhofer line, the onboard wavelength calibration can be processed by the spectral images themselves. In this paper, wavelength calibration is based on the modeled and measured atmospheric absorption spectra. The modeled spectra constructed by the atmospheric radiative transfer code. The spectral angle is used to determine the best spectral similarity between the modeled spectra and measured spectra and estimates the wavelength position. The smile shape can be obtained when the matching process across all columns of the data. The present method is successful applied on the Hyperion data. The value of the wavelength shift is obtained by shape matching of oxygen absorption feature and the characteristics are comparable to that of the prelaunch measurements.

  5. Three-dimensional modeling of beam emission spectroscopy measurements in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Guszejnov, D.; Pokol, G. I. [Department of Nuclear Techniques, Budapest University of Technology and Economics, Association EURATOM, H-1111 Budapest (Hungary); Pusztai, I. [Nuclear Engineering, Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Refy, D.; Zoletnik, S. [MTA Wigner FK RMI, Association EURATOM, Pf. 49, H-1525 Budapest (Hungary); Lampert, M. [Department of Nuclear Techniques, Budapest University of Technology and Economics, Association EURATOM, H-1111 Budapest (Hungary); MTA Wigner FK RMI, Association EURATOM, Pf. 49, H-1525 Budapest (Hungary); Nam, Y. U. [National Fusion Research Institute, Gwahangno 113, Daejeon 305-333 (Korea, Republic of)

    2012-11-15

    One of the main diagnostic tools for measuring electron density profiles and the characteristics of long wavelength turbulent wave structures in fusion plasmas is beam emission spectroscopy (BES). The increasing number of BES systems necessitated an accurate and comprehensive simulation of BES diagnostics, which in turn motivated the development of the Rate Equations for Neutral Alkali-beam TEchnique (RENATE) simulation code that is the topic of this paper. RENATE is a modular, fully three-dimensional code incorporating all key features of BES systems from the atomic physics to the observation, including an advanced modeling of the optics. Thus RENATE can be used both in the interpretation of measured signals and the development of new BES systems. The most important components of the code have been successfully benchmarked against other simulation codes. The primary results have been validated against experimental data from the KSTAR tokamak.

  6. Acoustic Emission Technology and Application

    International Nuclear Information System (INIS)

    Joo, Y. S.; Lim, S. H.; Eom, H. S.; Kim, J. H.; Jung, H. K.

    2003-10-01

    Acoustic emission is the elastic wave that is generated by the rapid release of energy from the localized sources within a material. After the observation of acoustic emission phenomenon in 1950, the research and further investigation had been performed. Acoustic emission examination becomes a rapidly matured nondestructive testing method with demonstrated capabilities for characterizing material behavior and for detecting the defect. It is of interest as a possible passive monitoring technique for detecting, locating and characterizing the defects in component and structure. Acoustic emission technology has recently strengthened the on-line monitoring application for the detection of incipient failures and the assurance of structural integrity. The field of acoustic emission testing is still growing vigorously and presents many challenges. Especially, acoustic emission has been successfully applied in the leak detection of primary pressure boundary of nuclear power plants. In this state-of-art report, the principle, measurement and field applications of acoustic emission technique is reviewed and summarized. Acoustic emission technology will contribute to the assurance of nuclear safety as the on-line monitoring technique of structural integrity of NSSS components and structures

  7. Kinetic energy dependence of carrier diffusion in a GaAs epilayer studied by wavelength selective PL imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S. [University of North Carolina at Charlotte, Charlotte, NC 28223 (United States); Providence High School, Charlotte, NC 28270 (United States); Su, L.Q.; Kon, J. [University of North Carolina at Charlotte, Charlotte, NC 28223 (United States); Gfroerer, T. [Davidson College, Davidson, NC 28035 (United States); Wanlass, M.W. [National Renewable Energy Laboratory, Golden, CO 80401 (United States); Zhang, Y., E-mail: yong.zhang@uncc.edu [University of North Carolina at Charlotte, Charlotte, NC 28223 (United States)

    2017-05-15

    Photoluminescence (PL) imaging has been shown to be an efficient technique for investigating carrier diffusion in semiconductors. In the past, the measurement was typically carried out by measuring at one wavelength (e.g., at the band gap) or simply the whole emission band. At room temperature in a semiconductor like GaAs, the band-to-band PL emission may occur in a spectral range over 200 meV, vastly exceeding the average thermal energy of about 26 meV. To investigate the potential dependence of the carrier diffusion on the carrier kinetic energy, we performed wavelength selective PL imaging on a GaAs double hetero-structure in a spectral range from about 70 meV above to 50 meV below the bandgap, extracting the carrier diffusion lengths at different PL wavelengths by fitting the imaging data to a theoretical model. The results clearly show that the locally generated carriers of different kinetic energies mostly diffuse together, maintaining the same thermal distribution throughout the diffusion process. Potential effects related to carrier density, self-absorption, lateral wave-guiding, and local heating are also discussed.

  8. Two-wavelength, passive self-injection-controlled operation of diode-pumped cw Yb-doped crystal lasers.

    Science.gov (United States)

    Louyer, Yann; Wallerand, Jean-Pierre; Himbert, Marc; Deneva, Margarita; Nenchev, Marin

    2003-09-20

    We demonstrate and investigate a peculiar mode of cw Yb3+-doped crystal laser operation when two emissions, at two independently tunable wavelengths, are simultaneously produced. Both emissions are generated from a single pumped volume and take place in either a single beam or spatially separated beams. The laser employs original two-channel cavities that use a passive self-injection-locking (PSIL) control to reduce intracavity loss. The advantages of the application of the PSIL technique and some limitations are shown. The conditions for two-wavelength multimode operation of the cw quasi-three-level diode-pumped Yb3+ lasers and the peculiarity of such an operation are carried out both theoretically and experimentally. The results reported are based on the example of a Yb3+:GGG laser but similar results are also obtained with a Yb3+:YAG laser. The laser operates in the 1023-1033-nm (1030-1040-nm) range with a total output power of 0.4 W. A two-wavelength, single longitudinal mode generation is also obtained.

  9. High resolution polarimetry of the Sun at 3. 7 and 11. 1 cm wavelengths. [Stokes parameters, polarization

    Energy Technology Data Exchange (ETDEWEB)

    Lang, K R [Tufts Univ., Medford, Mass. (USA). Dept. of Physics

    1977-04-01

    The four Stokes parameters are presented for interferometric observations of the Sun at wavelengths of lambda=3.7 cm and lambda=11 cm with angular resolutions between 2.7 and 36.7 seconds of arc. An H..cap alpha.. solar flare of importance SN and type C has a radio wavelength (lambda=3.7 cm) size of 5 seconds of arc, a flux density of 0.3 x 10/sup -22/Wm/sup -2/Hz/sup -1/, and a brightness temperature on the order of 10/sup 7/K. The radio flare is 30% left circularly polarized at lambda=3.7 cm, 70% left circularly polarized at lambda=11 cm, and no detectable linear polarization was observed at either wavelength. During a forty hour observation of sunspot region McMath No 13926 no substantial variations in circular polarization were observed, whereas one hour prior to the eruption of a solar flare dramatic changes in circular polarization were observed. Small scale features whose angular sizes are on the order of five seconds of arc exhibit changes of circular polarization of up to 80%. At times other than those immediately preceding flare emission, the degree of circular polarization was the same as the two wavelengths but the sign was reversed. This situation can be explained if magnetic fields of intensity H<=1000 G and electron densities of Nsub(e)>=10/sup 7/cm/sup -3/ are present.

  10. From laboratory to the sky: Th-Ar wavelength standards for the cryogenic infrared echelle spectrograph (CRIRES)

    Energy Technology Data Exchange (ETDEWEB)

    Kerber, Florian; Bristow, Paul [European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching (Germany); Nave, Gillian; Sansonetti, Craig J [National Institute of Standards and Technology, Gaithersburg, MD (United States)], E-mail: fkerber@eso.org, E-mail: gillian.nave@nist.gov, E-mail: craig.sansonetti@nist.gov, E-mail: bristowp@eso.org

    2009-05-15

    We report on the collaborative effort of the European Southern Observatory (ESO) and the National Institute of Standards and Technology (NIST) to establish-through laboratory measurements-wavelength standards in the near-infrared (IR) emission line spectrum of a low current Th-Ar hollow cathode lamp. These standards are now routinely used for the wavelength calibration of the cryogenic infrared echelle spectrograph (CRIRES) operated at one of the unit telescopes of the very large telescope (VLT) at ESO's La Silla Paranal Observatory in Chile. The availability of highly accurate wavelength standards from a commercially available calibration source permits a shift to a new operational paradigm for high-resolution IR spectroscopy. Wavelength calibration no longer has to rely on atmospheric features but can make use of laboratory traceable reference data as is normally done in the ultraviolet and visible regions. This opens the door for more quantitative spectroscopic work in the near-IR. To illustrate the potential impact of this development, we briefly review the current state of affairs in IR astronomy and its projected future. With the advent of the next generation of extremely large ground-based telescopes the IR region will become the most powerful window on the universe within the next 10-15 years. We conclude with a short outlook on the contribution atomic physics can make to this evolution.

  11. Derivation of gravity wave intrinsic parameters and vertical wavelength using a single scanning OH(3-1) airglow spectrometer

    Science.gov (United States)

    Wüst, Sabine; Offenwanger, Thomas; Schmidt, Carsten; Bittner, Michael; Jacobi, Christoph; Stober, Gunter; Yee, Jeng-Hwa; Mlynczak, Martin G.; Russell, James M., III

    2018-05-01

    For the first time, we present an approach to derive zonal, meridional, and vertical wavelengths as well as periods of gravity waves based on only one OH* spectrometer, addressing one vibrational-rotational transition. Knowledge of these parameters is a precondition for the calculation of further information, such as the wave group velocity vector.OH(3-1) spectrometer measurements allow the analysis of gravity wave ground-based periods but spatial information cannot necessarily be deduced. We use a scanning spectrometer and harmonic analysis to derive horizontal wavelengths at the mesopause altitude above Oberpfaffenhofen (48.09° N, 11.28° E), Germany for 22 nights in 2015. Based on the approximation of the dispersion relation for gravity waves of low and medium frequencies and additional horizontal wind information, we calculate vertical wavelengths. The mesopause wind measurements nearest to Oberpfaffenhofen are conducted at Collm (51.30° N, 13.02° E), Germany, ca. 380 km northeast of Oberpfaffenhofen, by a meteor radar.In order to compare our results, vertical temperature profiles of TIMED-SABER (thermosphere ionosphere mesosphere energetics dynamics, sounding of the atmosphere using broadband emission radiometry) overpasses are analysed with respect to the dominating vertical wavelength.

  12. Multi-wavelength study of the Seyfert 1 galaxy NGC 3783 with XMM-Newton

    CERN Document Server

    Blustin, A J; Behar, E; Kaastra, J S; Kahn, S M; Page, M J; Sako, M; Steenbrugge, K C

    2002-01-01

    We present the analysis of multi-wavelength XMM-Newton data from the Seyfert galaxy NGC 3783, including UV imaging, X-ray and UV lightcurves, the 0.2-10 keV X-ray continuum, the iron K-alpha emission line, and high-resolution spectroscopy and modelling of the soft X-ray warm absorber. The 0.2-10 keV spectral continuum can be well reproduced by a power-law at higher energies; we detect a prominent Fe K-alpha emission line, with both broad and narrow components, and a weaker emission line at 6.9 keV which is probably a combination of Fe K-beta and Fe XXVI. We interpret the significant deficit of counts in the soft X-ray region as being due to absorption by ionised gas in the line of sight. This is demonstrated by the large number of narrow absorption lines in the RGS spectrum from iron, oxygen, nitrogen, carbon, neon, argon, magnesium, silicon and sulphur. The wide range of iron states present in the spectrum enables us to deduce the ionisation structure of the absorbing medium. We find that our spectrum contai...

  13. Wavelength selection in traveling-wave convection in a fluid mixture

    International Nuclear Information System (INIS)

    Surko, C.M.; Eaton, K.D.; Baxter, G.W.; Iwata, K.

    1993-01-01

    The mechanisms by which a one-dimensional pattern of traveling waves changes wavelength (i.e. the Eckhaus instability) is studied in a binary fluid mixture. Propagating wavelength modulations develop when the Rayleigh number of the system is decreased below a wavelength-dependent threshold, commonly referred to as the Eckhaus boundary. These wavelength modulations increase in amplitude and narrow in spatial extent until they trigger the creation or annihilation of convection roll pairs and thereby change the average wavelength of the system. The authors find qualitatively different dynamics for wavelength-increasing events and wavelength-decreasing events; these differences are due to the strong wavelength dependence of the group velocity

  14. Effect of graphene on plasmonic metasurfaces at infrared wavelengths

    Directory of Open Access Journals (Sweden)

    Shinpei Ogawa

    2013-11-01

    Full Text Available Significant enhancement of infrared transmittance by the presence of a graphene layer on a plasmonic metasurface (PLM has been demonstrated. PLMs with different configurations were fabricated, and their transmittance with and without graphene was compared. Selective enhancement by graphene occurred at the plasmon resonance wavelength. The degree of enhancement was found to depend on the width of the gap between the periodic metal regions in the PLM. A maximum enhancement of ∼210% was achieved at a wavelength of 10 μm. The ability to achieve such a drastic increase in transmittance at the plasmon resonant wavelength is expected to lead to improvements in the performance of energy collecting devices and optical sensors.

  15. In-vacuum long-wavelength macromolecular crystallography.

    Science.gov (United States)

    Wagner, Armin; Duman, Ramona; Henderson, Keith; Mykhaylyk, Vitaliy

    2016-03-01

    Structure solution based on the weak anomalous signal from native (protein and DNA) crystals is increasingly being attempted as part of synchrotron experiments. Maximizing the measurable anomalous signal by collecting diffraction data at longer wavelengths presents a series of technical challenges caused by the increased absorption of X-rays and larger diffraction angles. A new beamline at Diamond Light Source has been built specifically for collecting data at wavelengths beyond the capability of other synchrotron macromolecular crystallography beamlines. Here, the theoretical considerations in support of the long-wavelength beamline are outlined and the in-vacuum design of the endstation is discussed, as well as other hardware features aimed at enhancing the accuracy of the diffraction data. The first commissioning results, representing the first in-vacuum protein structure solution, demonstrate the promising potential of the beamline.

  16. Method of stabilizing a laser apparatus with wavelength converter

    DEFF Research Database (Denmark)

    2013-01-01

    and to output the frequency-converted radiation (213), the frequency-converted radiation having at least a second wavelength different from the first wavelength, the diode laser (10) comprising at least a first and a second section (222,223), a first contact (220) for injecting a first current (I1......) into the first section (222), a second contact (221) for injecting a second current (I2) into the second section (223), and means for controlling a temperature of the diode laser; wherein the method comprises monitoring a first parameter indicative of the power content of a dominant lobe of the first radiation......A method of controlling beam quality and stability of a laser apparatus, the laser apparatus comprising, a diode laser (10) providing first radiation of at least a first wavelength, and a frequency conversion unit (12) configured to frequency-convert the first radiation from the diode laser...

  17. Do shorter wavelengths improve contrast in optical mammography?

    International Nuclear Information System (INIS)

    Taroni, P; Pifferi, A; Torricelli, A; Spinelli, L; Danesini, G M; Cubeddu, R

    2004-01-01

    The detection of tumours with time-resolved transmittance imaging relies essentially on blood absorption. Previous theoretical and phantom studies have shown that both contrast and spatial resolution of optical images are affected by the optical properties of the background medium, and high absorption and scattering are generally beneficial. Based on these observations, wavelengths shorter than presently used (680-780 nm) could be profitable for optical mammography. A study was thus performed analysing time-resolved transmittance images at 637, 656, 683 and 785 nm obtained from 26 patients bearing 16 tumours and 15 cysts. The optical contrast proved to increase upon decreasing wavelengths for the detection of cancers in late-gated intensity images, with higher gain in contrast for lesions of smaller size (<1.5 cm diameter). For cysts either a progressive increase or decrease in contrast with wavelength was observed in scattering images

  18. Pulsed hybrid dual wavelength Y-branch-DFB laser-tapered amplifier system suitable for water vapor detection at 965 nm with 16 W peak power

    Science.gov (United States)

    Vu, Thi N.; Klehr, Andreas; Sumpf, Bernd; Hoffmann, Thomas; Liero, Armin; Tränkle, Günther

    2016-03-01

    A master oscillator power amplifier system emitting alternatingly at two neighbored wavelengths around 965 nm is presented. As master oscillator (MO) a Y-branch DFB-laser is used. The two branches, which can be individually controlled, deliver the two wavelengths needed for a differential absorption measurement of water vapor. Adjusting the current through the DFB sections, the wavelength can be adjusted with respect to the targeted either "on" or "off" resonance, respectively wavelength λon or wavelength λoff. The emission of this laser is amplified in a tapered amplifier (TA). The ridge waveguide section of the TA acts as optical gate to generate short pulses with duration of 8 ns at a repetition rate of 25 kHz, the flared section is used for further amplification to reach peak powers up to 16 W suitable for micro-LIDAR (Light Detection and Ranging). The necessary pulse current supply user a GaN-transistor based driver electronics placed close to the power amplifier (PA). The spectral properties of the emission of the MO are preserved by the PA. A spectral line width smaller than 10 pm and a side mode suppression ratio (SMSR) of 37 dB are measured. These values meet the demands for water vapor absorption measurements under atmospheric conditions.

  19. Broadband multi-wavelength Brillouin lasers with an operating wavelength range of 1500–1600 nm generated by four-wave mixing in a dual wavelength Brillouin fiber laser cavity

    Science.gov (Unite