WorldWideScience

Sample records for far-infrared spectral energy

  1. Microwave, Millimeter, Submillimeter, and Far Infrared Spectral Databases

    Science.gov (United States)

    Pearson, J. C.; Pickett, H. M.; Drouin, B. J.; Chen, P.; Cohen, E. A.

    2002-01-01

    The spectrum of most known astrophysical molecules is derived from transitions between a few hundred to a few hundred thousand energy levels populated at room temperature. In the microwave and millimeter wave regions. spectroscopy is almost always performed with traditional microwave techniques. In the submillimeter and far infrared microwave technique becomes progressively more technologically challenging and infrared techniques become more widely employed as the wavelength gets shorter. Infrared techniques are typically one to two orders of magnitude less precise but they do generate all the strong features in the spectrum. With microwave technique, it is generally impossible and rarely necessary to measure every single transition of a molecular species, so careful fitting of quantum mechanical Hamiltonians to the transitions measured are required to produce the complete spectral picture of the molecule required by astronomers. The fitting process produces the most precise data possible and is required in the interpret heterodyne observations. The drawback of traditional microwave technique is that precise knowledge of the band origins of low lying excited states is rarely gained. The fitting of data interpolates well for the range of quantum numbers where there is laboratory data, but extrapolation is almost never precise. The majority of high resolution spectroscopic data is millimeter or longer in wavelength and a very limited number of molecules have ever been studied with microwave techniques at wavelengths shorter than 0.3 millimeters. The situation with infrared technique is similarly dire in the submillimeter and far infrared because the black body sources used are competing with a very significant thermal background making the signal to noise poor. Regardless of the technique used the data must be archived in a way useful for the interpretation of observations.

  2. Analysis of cirrus cloud spectral signatures in the far infrared

    International Nuclear Information System (INIS)

    Maestri, T.; Rizzi, R.; Tosi, E.; Veglio, P.; Palchetti, L.; Bianchini, G.; Di Girolamo, P.; Masiello, G.; Serio, C.; Summa, D.

    2014-01-01

    This paper analyses high spectral resolution downwelling radiance measurements in the far infrared in the presence of cirrus clouds taken by the REFIR-PAD interferometer, deployed at 3500 m above the sea level at the Testa Grigia station (Italy), during the Earth COoling by WAter vapouR emission (ECOWAR) campaign. Atmospheric state and cloud geometry are characterised by the co-located millimeter-wave spectrometer GBMS and by radiosonde profile data, an interferometer (I-BEST) and a Raman lidar system deployed at a nearby location (Cervinia). Cloud optical depth and effective diameter are retrieved from REFIR-PAD data using a limited number of channels in the 820–960 cm −1 interval. The retrieved cloud parameters are the input data for simulations covering the 250–1100 cm −1 band in order to test our ability to reproduce the REFIR-PAD spectra in the presence of ice clouds. Inverse and forward simulations are based on the same radiative transfer code. A priori information concerning cloud ice vertical distribution is used to better constrain the simulation scheme and an analysis of the degree of approximation of the phase function within the radiative transfer codes is performed to define the accuracy of computations. Simulation-data residuals over the REFIR-PAD spectral interval show an excellent agreement in the window region, but values are larger than total measurement uncertainties in the far infrared. Possible causes are investigated. It is shown that the uncertainties related to the water vapour and temperature profiles are of the same order as the sensitivity to the a priori assumption on particle habits for an up-looking configuration. In case of a down-looking configuration, errors due to possible incorrect description of the water vapour profile would be drastically reduced. - Highlights: • We analyze down-welling spectral radiances in the far infrared (FIR) spectrum. • Discuss the scattering in the fir and the ice crystals phase function

  3. Far-infrared spectral studies of magnesium and aluminum co ...

    Indian Academy of Sciences (India)

    Far-infrared absorption spectroscopy has been used to study the occurrence of var- ... density of the products was found to be about 83% of the X-ray density. ..... [15] B D Cullity, Elements of X-ray diffraction (Addison-Wesley Press, Reading, ...

  4. Red but not dead: unveiling the star-forming far-infrared spectral energy distribution of SpARCS brightest cluster galaxies at 0 < z < 1.8

    Science.gov (United States)

    Bonaventura, N. R.; Webb, T. M. A.; Muzzin, A.; Noble, A.; Lidman, C.; Wilson, G.; Yee, H. K. C.; Geach, J.; Hezaveh, Y.; Shupe, D.; Surace, J.

    2017-08-01

    We present the results of a Spitzer/Herschel infrared photometric analysis of the largest (716) and the highest-redshift (z = 1.8) sample of brightest cluster galaxies (BCGs), those from the Spitzer Adaptation of the Red-Sequence Cluster Survey Given the tension that exists between model predictions and recent observations of BCGs at z energy distributions (SEDs) to a variety of model templates in the literature, we identify the major sources of their infrared energy output, in multiple redshift bins between 0 solar masses per year down to z = 0.5. This discovery challenges the accepted belief that BCGs should only passively evolve through a series of gas-poor, minor mergers since z ˜ 4, but agrees with an improved semi-analytic model of hierarchical structure formation that predicts star-forming BCGs throughout the epoch considered. We attribute the star formation inferred from the stacked infrared SEDs to both major and minor 'wet' (gas-rich) mergers, based on a lack of key signatures (to date) of cooling-flow-induced star formation, as well as a number of observational and simulation-based studies that support this scenario.

  5. Far-infrared Spectral Radiance Observations and Modeling of Arctic Cirrus: Preliminary Results From RHUBC

    Science.gov (United States)

    Humpage, Neil; Green, Paul D.; Harries, John E.

    2009-03-01

    Recent studies have highlighted the important contribution of the far-infrared (electromagnetic radiation with wavelengths greater than 12 μm) to the Earth's radiative energy budget. In a cloud-free atmosphere, a significant fraction of the Earth's cooling to space from the mid- and upper troposphere takes place via the water vapor pure rotational band between 17 and 33 μm. Cirrus clouds also play an important role in the Earth's outgoing longwave radiation. The effect of cirrus on far-infrared radiation is of particular interest, since the refractive index of ice depends strongly on wavelength in this spectral region. The scattering properties of ice crystals are directly related to the refractive index, so consequently the spectral signature of cirrus measured in the FIR is sensitive to the cloud microphysical properties [1, 2]. By examining radiances measured at wavelengths between the strong water vapor absorption lines in the FIR, the understanding of the relationship between cirrus microphysics and the radiative transfer of thermal energy through cirrus may be improved. Until recently, very few observations of FIR spectral radiances had been made. The Tropospheric Airborne Fourier Transform Spectrometer (TAFTS) was developed by Imperial College to address this lack of observational data. TAFTS observes both zenith and nadir radiances at 0.1 cm-1 resolution, between 80 and 600 cm-1. During February and March 2007, TAFTS was involved in RHUBC (the Radiative Heating in Under-explored Bands Campaign), an ARM funded field campaign based at the ACRF-North Slope of Alaska site near Barrow, situated at 71° latitude. Infrared zenith spectral observations were taken by both TAFTS and the AERI-ER (spectral range 400-3300 cm-1) from the ground during both cloud-free and cirrus conditions. A wide range of other instrumentation was also available at the site, including a micropulse lidar, 35 GHz radar and the University of Colorado/NOAA Ground-based Scanning Radiometer

  6. Quasi-optical analysis of a far-infrared spatio-spectral space interferometer concept

    Science.gov (United States)

    Bracken, C.; O'Sullivan, C.; Murphy, J. A.; Donohoe, A.; Savini, G.; Lightfoot, J.; Juanola-Parramon, R.; Fisica Consortium

    2016-07-01

    FISICA (Far-Infrared Space Interferometer Critical Assessment) was a three year study of a far-infrared spatio-spectral double-Fourier interferometer concept. One of the aims of the FISICA study was to set-out a baseline optical design for such a system, and to use a model of the system to simulate realistic telescope beams for use with an end-to-end instrument simulator. This paper describes a two-telescope (and hub) baseline optical design that fulfils the requirements of the FISICA science case, while minimising the optical mass of the system. A number of different modelling techniques were required for the analysis: fast approximate simulation tools such as ray tracing and Gaussian beam methods were employed for initial analysis, with GRASP physical optics used for higher accuracy in the final analysis. Results are shown for the predicted far-field patterns of the telescope primary mirrors under illumination by smooth walled rectangular feed horns. Far-field patterns for both on-axis and off-axis detectors are presented and discussed.

  7. Wide-field Spatio-Spectral Interferometry: Bringing High Resolution to the Far- Infrared

    Science.gov (United States)

    Leisawitx, David

    Wide-field spatio-spectral interferometry combines spatial and spectral interferometric data to provide integral field spectroscopic information over a wide field of view. This technology breaks through a mission cost barrier that stands in the way of resolving spatially and measuring spectroscopically at far-infrared wavelengths objects that will lead to a deep understanding of planetary system and galaxy formation processes. A space-based far-IR interferometer will combine Spitzer s superb sensitivity with a two order of magnitude gain in angular resolution, and with spectral resolution in the thousands. With the possible exception of detector technology, which is advancing with support from other research programs, the greatest challenge for far-IR interferometry is to demonstrate that the interferometer will actually produce the images and spectra needed to satisfy mission science requirements. With past APRA support, our team has already developed the highly specialized hardware testbed, image projector, computational model, and image construction software required for the proposed effort, and we have access to an ideal test facility.

  8. Detection of small surface vessels in near, medium, and far infrared spectral bands

    Science.gov (United States)

    Dulski, R.; Milewski, S.; Kastek, M.; Trzaskawka, P.; Szustakowski, M.; Ciurapinski, W.; Zyczkowski, M.

    2011-11-01

    Protection of naval bases and harbors requires close co-operation between security and access control systems covering land areas and those monitoring sea approach routes. The typical location of naval bases and harbors - usually next to a large city - makes it difficult to detect and identify a threat in the dense regular traffic of various sea vessels (i.e. merchant ships, fishing boats, tourist ships). Due to the properties of vessel control systems, such as AIS (Automatic Identification System), and the effectiveness of radar and optoelectronic systems against different targets it seems that fast motor boats called RIB (Rigid Inflatable Boat) could be the most serious threat to ships and harbor infrastructure. In the paper the process and conditions for the detection and identification of high-speed boats in the areas of ports and naval bases in the near, medium and far infrared is presented. Based on the results of measurements and recorded thermal images the actual temperature contrast delta T (RIB / sea) will be determined, which will further allow to specify the theoretical ranges of detection and identification of the RIB-type targets for an operating security system. The data will also help to determine the possible advantages of image fusion where the component images are taken in different spectral ranges. This will increase the probability of identifying the object by the multi-sensor security system equipped additionally with the appropriate algorithms for detecting, tracking and performing the fusion of images from the visible and infrared cameras.

  9. Multimode simulations of a wide field of view double-Fourier far-infrared spatio-spectral interferometer

    Science.gov (United States)

    Bracken, Colm P.; Lightfoot, John; O'Sullivan, Creidhe; Murphy, J. Anthony; Donohoe, Anthony; Savini, Giorgio; Juanola-Parramon, Roser; The Fisica Consortium, On Behalf Of

    2018-01-01

    In the absence of 50-m class space-based observatories, subarcsecond astronomy spanning the full far-infrared wavelength range will require space-based long-baseline interferometry. The long baselines of up to tens of meters are necessary to achieve subarcsecond resolution demanded by science goals. Also, practical observing times command a field of view toward an arcminute (1‧) or so, not achievable with a single on-axis coherent detector. This paper is concerned with an application of an end-to-end instrument simulator PyFIInS, developed as part of the FISICA project under funding from the European Commission's seventh Framework Programme for Research and Technological Development (FP7). Predicted results of wide field of view spatio-spectral interferometry through simulations of a long-baseline, double-Fourier, far-infrared interferometer concept are presented and analyzed. It is shown how such an interferometer, illuminated by a multimode detector can recover a large field of view at subarcsecond angular resolution, resulting in similar image quality as that achieved by illuminating the system with an array of coherent detectors. Through careful analysis, the importance of accounting for the correct number of higher-order optical modes is demonstrated, as well as accounting for both orthogonal polarizations. Given that it is very difficult to manufacture waveguide and feed structures at sub-mm wavelengths, the larger multimode design is recommended over the array of smaller single mode detectors. A brief note is provided in the conclusion of this paper addressing a more elegant solution to modeling far-infrared interferometers, which holds promise for improving the computational efficiency of the simulations presented here.

  10. Developing Wide-Field Spatio-Spectral Interferometry for Far-Infrared Space Applications

    Science.gov (United States)

    Leisawitz, David; Bolcar, Matthew R.; Lyon, Richard G.; Maher, Stephen F.; Memarsadeghi, Nargess; Rinehart, Stephen A.; Sinukoff, Evan J.

    2012-01-01

    Interferometry is an affordable way to bring the benefits of high resolution to space far-IR astrophysics. We summarize an ongoing effort to develop and learn the practical limitations of an interferometric technique that will enable the acquisition of high-resolution far-IR integral field spectroscopic data with a single instrument in a future space-based interferometer. This technique was central to the Space Infrared Interferometric Telescope (SPIRIT) and Submillimeter Probe of the Evolution of Cosmic Structure (SPECS) space mission design concepts, and it will first be used on the Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII). Our experimental approach combines data from a laboratory optical interferometer (the Wide-field Imaging Interferometry Testbed, WIIT), computational optical system modeling, and spatio-spectral synthesis algorithm development. We summarize recent experimental results and future plans.

  11. Photoconductor arrays for a spectral-photometric far-infrared camera on SOFIA

    Science.gov (United States)

    Wolf, Juergen; Driescher, Hans; Schubert, Josef; Rabanus, D.; Paul, E.; Roesner, K.

    1998-04-01

    The Stratospheric Observatory for Infrared Astronomy, SOFIA, is a joint US and German project and will start observations from altitudes up to 45,000 ft in late 2001. The 2.5 m telescope is being developed in Germany while the 747- aircraft modifications and preparation of the observatory's operations center is done by a US consortium. Several research institutions and universities of both countries have started to develop science instruments. The DLR Institute of Space Sensor Technology in Berlin plans on a spectral-photometric camera working in the 20 to 220 micrometers wavelength range, using doped silicon and germanium extrinsic photoconductors in large, 2D arrays: silicon blocked-impurity band detectors, Ge:Ga and stressed Ge:Ga. While the silicon array will be commercially available, the germanium arrays have to be developed, including their cryogenic multiplexers. Partner institutions in Germany and the US will support the development of the instrument and its observations.

  12. Integrative Multi-Spectral Sensor Device for Far-Infrared and Visible Light Fusion

    Science.gov (United States)

    Qiao, Tiezhu; Chen, Lulu; Pang, Yusong; Yan, Gaowei

    2018-06-01

    Infrared and visible light image fusion technology is a hot spot in the research of multi-sensor fusion technology in recent years. Existing infrared and visible light fusion technologies need to register before fusion because of using two cameras. However, the application effect of the registration technology has yet to be improved. Hence, a novel integrative multi-spectral sensor device is proposed for infrared and visible light fusion, and by using the beam splitter prism, the coaxial light incident from the same lens is projected to the infrared charge coupled device (CCD) and visible light CCD, respectively. In this paper, the imaging mechanism of the proposed sensor device is studied with the process of the signals acquisition and fusion. The simulation experiment, which involves the entire process of the optic system, signal acquisition, and signal fusion, is constructed based on imaging effect model. Additionally, the quality evaluation index is adopted to analyze the simulation result. The experimental results demonstrate that the proposed sensor device is effective and feasible.

  13. Far infrared photoconductors

    International Nuclear Information System (INIS)

    Leotin, J.; Meny, C.

    1990-01-01

    This paper presents the development of far infrared photoconductors for the focal plane of a spaceborne instrument named SAFIRE. SAFIRE (Spectroscopy of the Atmosphere using Far-Infrared Emission) belongs to the EOS program (Earth Observing System) and is now in the definition phase. It is a joint effort by scientists from the United States, Great Britain, Italy and France for a new generation of atmosphere sensor. The overall goal of the SAFIRE experiment is to improve the understanding of the ozone distribution in the middle atmosphere by conducting global scale measurements of the important chemical, radiative and dynamical processes which influence its changes. This will be accomplished by the measurement of the far infrared thermal limb emission in seven spectral channels covering the range 80 to 400 cm -1 with a maximum resolution of 0.004 cm -1 . For example key gases like OH, O, HO 2 , N 2 O 5 will be probed for the first time. Achievement of the required detector sensitivity in the far-infrared imposes the choice of photoconductive detectors operating at liquid helium temperatures. Germanium doped with gallium is selected for six channels whereas germanium doped with beryllium is suitable for the N 2 O 5 channel. Both photoconductors Ge:Ga and Ge:Be benefit from a well established material technology. A better wavelength coverage of channel 1 is achieved by applying a small uniaxial stress of the order of 0.1 GPa on the Ge:Ga photoconductors. The channel 6B wavelength coverage could be improved by using zinc-doped-germanium (Ge:Zn) or, much better, by using a Blocked Impurity band silicon detector doped with antimony (BIB Si:Sb). The later is developed as an optional basis

  14. Energy levels and far-infrared optical absorption of impurity doped semiconductor nanorings: Intense laser and electric fields effects

    Energy Technology Data Exchange (ETDEWEB)

    Barseghyan, M.G., E-mail: mbarsegh@ysu.am

    2016-11-10

    Highlights: • The electron-impurity interaction on energy levels in nanoring have been investigated. • The electron-impurity interaction on far-infrared absorption have been investigated. • The energy levels are more stable for higher values of electric field. - Abstract: The effects of electron-impurity interaction on energy levels and far-infrared absorption in semiconductor nanoring under the action of intense laser and lateral electric fields have been investigated. Numerical calculations are performed using exact diagonalization technique. It is found that the electron-impurity interaction and external fields change the energy spectrum dramatically, and also have significant influence on the absorption spectrum. Strong dependence on laser field intensity and electric field of lowest energy levels, also supported by the Coulomb interaction with impurity, is clearly revealed.

  15. A Low-Energy-Spread Rf Accelerator for a Far-Infrared Free-Electron Laser

    NARCIS (Netherlands)

    van der Geer, C. A. J.; Bakker, R. J.; van der Meer, A. F. G.; van Amersfoort, P. W.; Gillespie, W. A.; Saxon, G.; Poole, M. W.

    1993-01-01

    A high electron current and a small energy spread are essential for the operation of a free electron laser (FEL). In this paper we discuss the design and performance of the accelerator for FELIX, the free electron laser for infrared experiments. The system consists of a thermionic gun, a prebuncher,

  16. Far-infrared properties of optically selected quasars

    International Nuclear Information System (INIS)

    Edelson, R.A.

    1986-01-01

    The far-infrared properties of 10, optically selected quasars were studied on the basis of pointed IRAS observations and ground-based near-infrared and radio measurements. Nine of these quasars were detected in at least three IRAS bands. The flat spectral energy distributions characterizing these optically selected quasars together with large 60-100-micron luminosities suggest that the infrared emission is dominated by nonthermal radiation. Seven of the nine quasars with far-infrared detections were found to have low-frequency turnovers. 12 references

  17. Simultaneous retrieval of water vapour, temperature and cirrus clouds properties from measurements of far infrared spectral radiance over the Antarctic Plateau

    Science.gov (United States)

    Di Natale, Gianluca; Palchetti, Luca; Bianchini, Giovanni; Del Guasta, Massimo

    2017-03-01

    The possibility separating the contributions of the atmospheric state and ice clouds by using spectral infrared measurements is a fundamental step to quantifying the cloud effect in climate models. A simultaneous retrieval of cloud and atmospheric parameters from infrared wideband spectra will allow the disentanglement of the spectral interference between these variables. In this paper, we describe the development of a code for the simultaneous retrieval of atmospheric state and ice cloud parameters, and its application to the analysis of the spectral measurements acquired by the Radiation Explorer in the Far Infrared - Prototype for Applications and Development (REFIR-PAD) spectroradiometer, which has been in operation at Concordia Station on the Antarctic Plateau since 2012. The code performs the retrieval with a computational time that is comparable with the instrument acquisition time. Water vapour and temperature profiles and the cloud optical and microphysical properties, such as the generalised effective diameter and the ice water path, are retrieved by exploiting the 230-980 cm-1 spectral band. To simulate atmospheric radiative transfer, the Line-By-Line Radiative Transfer Model (LBLRTM) has been integrated with a specifically developed subroutine based on the δ-Eddington two-stream approximation, whereas the single-scattering properties of cirrus clouds have been derived from a database for hexagonal column habits. In order to detect ice clouds, a backscattering and depolarisation lidar, co-located with REFIR-PAD has been used, allowing us to infer the position and the cloud thickness to be used in the retrieval. A climatology of the vertical profiles of water vapour and temperature has been performed by using the daily radiosounding available at the station at 12:00 UTC. The climatology has been used to build an a priori profile correlation to constrain the fitting procedure. An optimal estimation method with the Levenberg-Marquardt approach has been

  18. Far infrared observations of the galactic center

    International Nuclear Information System (INIS)

    Gatley, I.

    1977-01-01

    Maps of a region 10' in diameter around the galactic center made simultaneously in three wavelength bands at 30 μm, 50 μm, and 100 μm with approximately 1' resolution are presented, and the distribution of far infrared luminosity and color temperature across this region is derived. The position of highest far infrared surface brightness coincides with the peak of the late-type stellar distribution and with the H II region Sgr A West. The high spatial and temperature resolution of the data is used to identify features of the far infrared maps with known sources of near infrared, radio continuum, and molecular emission. The emission mechanism and energy sources for the far infrared radiation are anslyzed qualitatively, and it is concluded that all of the observed far infrared radiation from the galactic center region can be attributed to thermal emission from dust heated both by the late-type stars and by the ultraviolet sources which ionize the H II regions. A self-consistent model for the far infrared emission from the galactic center region is presented. It is found that the visual extinction across the central 10 pc of the galaxy is only about 3 magnitudes, and that the dust density is fairly uniform in this region. An upper limit of 10 7 L/sub mass/ is set on the luminosity of any presently unidentified source of 0.1 to 1 μm radiation at the galactic center. Additional maps in the vicinity of the source Sgr B2 and observations of Sgr C bring the total number of H II regions within 1 0 of the galactic center studied by the present experiment to nine. The far infrared luminosity, color temperature and optical depth of these regions and the ratio of infrared flux to radio continuum flux lie in the range characteristic of spiral arm H II regions. The far infrared results are therefore consistent with the data that the galactic center H II regions are ionized by luminous, early type stars

  19. Advanced far infrared detectors

    International Nuclear Information System (INIS)

    Haller, E.E.

    1993-05-01

    Recent advances in photoconductive and bolometric semiconductor detectors for wavelength 1 mm > λ > 50 μm are reviewed. Progress in detector performance in this photon energy range has been stimulated by new and stringent requirements for ground based, high altitude and space-borne telescopes for astronomical and astrophysical observations. The paper consists of chapters dealing with the various types of detectors: Be and Ga doped Ge photoconductors, stressed Ge:Ga devices and neutron transmutation doped Ge thermistors. Advances in the understanding of basic detector physics and the introduction of modern semiconductor device technology have led to predictable and reliable fabrication techniques. Integration of detectors into functional arrays has become feasible and is vigorously pursued by groups worldwide

  20. The far-infrared spectrum of the OH radical

    Science.gov (United States)

    Brown, J. M.; Schubert, J. E.; Evenson, K. M.; Radford, H. E.

    1982-01-01

    It is thought likely that the study of spectral lines in the far-infrared might provide at least as much information about the physics and chemistry of the interstellar environment as radioastronomy. However, by comparison with the microwave region, the far-infrared is largely unexplored. There is a pressing need for good laboratory data to aid searches and assignments of spectra from the interstellar clouds and nebulae. Brown et al. (1981) have conducted a study of the laser magnetic resonance (LMR) spectrum of the OH radical in its ground state at far-infrared wavelengths. The present investigation is concerned with the computation of the frequencies of individual hyperfine transitions involving all rotational levels up to J = 4 1/2. The results of the calculation are presented in a table. The results are summarized in a diagram which shows the low-lying energy levels of OH. The frequencies of transitions between levels studied directly in the LMR spectrum are quite reliable.

  1. Multi-layer Far-Infrared Component Technology, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I SBIR will demonstrate the feasibility of a process to create multi-layer thin-film optics for the far-infrared/sub-millimeter wave spectral region. The...

  2. Long-slit optical spectroscopy of powerful far-infrared galaxies - The nature of the nuclear energy source

    Science.gov (United States)

    Armus, Lee; Heckman, Timothy M.; Miley, George K.

    1989-01-01

    Optical spectroscopic data are presented for a sample of 47 powerful far-IR galaxies chosen for IR spectral shape, and for six other IR-bright galaxies. The stellar absorption lines expected from a population of old stars are generally very weak in the nuclei of the galaxies. Very weak Mg I absorption is found in regions well off the nucleus, implying that the visible spectrum is dominated by young stars and not by an AGN. At least one, and probably five, of the galaxies have detectable WR emission features, providing additional evidence for a young stellar population. About 20 percent of the galaxies have strong Balmer absorption lines, indicating the presence of a substantial intermediate-age stellar population. The equivalent width of the H-alpha emission line can be modeled as arising from a mixture of a large young population and an intermediate-age population of stars.

  3. Far-infrared spectrophotometer for astronomical observations

    Science.gov (United States)

    Moseley, H.; Silverberg, R. F.

    1981-01-01

    A liquid-helium-cooled far infrared spectrophotometer was built and used to make low resolution observations of the continua of several kinds of astronomical objects using the Kuiper Airborne Observatory. This instrument fills a gap in both sensitivity to continuum sources and spectral resolution between the broadband photometers with lambda/Delta lambda approximately 1 and spectrometers with lambda/Delta lambda greater than 50. While designed primarily to study planetary nebulae, the instrument permits study of the shape of the continua of many weak sources which cannot easily be observed with high resolution systems.

  4. Far-Infrared Spectroscopy of Weakly Bound Hydrated Cluster Molecules

    DEFF Research Database (Denmark)

    Andersen, Jonas

    The thermodynamic properties of condensed phases, the functionality of many materials and the molecular organization in biological organisms are all governed by the classes of non-covalent interactions that occur already on the microscopic scale between pairs of molecules. A detailed investigation...... of the intermolecular interactions between prototypical molecular assemblies are valuable for accurate descriptions of larger supramolecular systems such as materials, gas hydrates and biological macromolecules. The aim of this PhD dissertation is to investigate intermolecular interactions fora series of medium...... vibrational bands of the cluster molecules in the challenging far-infrared and terahertz spectral regions.A key parameter in the validation of the performance of theoretical predictions for weak non-covalent intermolecular interactions is the dissociation energy D0 that depends heavily on the class of large...

  5. Observation of galactic far-infrared ray

    International Nuclear Information System (INIS)

    Maihara, Toshinori; Oda, Naoki; Okuda, Haruyuki; Sugiyama, Takuya; Sakai, Kiyomi.

    1978-01-01

    Galactic far-infrared was observed to study the spatial distribution of interstellar dust. Far-infrared is emitted by interstellar dust distributing throughout the galactic plane. The observation of far-infrared is very important to study the overall structure of the galaxy, that is the structure of the galactic arm and gas distribution. The balloon experiment was conducted on May 25, 1978. The detector was a germanium bolometer cooled by liquid helium. The size of the detector is 1.6 mm in diameter. The geometrical factor was 4 x 10 3 cm 2 sr. The result showed that the longitude distribution of far-infrared at 150 μm correlated with H 166 α recombination line. This indicates that the observed far-infrared is emitted by interstellar dust heated by photons of Lyman continuum. (Yoshimori, M.)

  6. Direct observation of the discrete energy spectrum of two lanthanide-based single-chain magnets by far-infrared spectroscopy

    Science.gov (United States)

    Haas, Sabrina; Heintze, Eric; Zapf, Sina; Gorshunov, Boris; Dressel, Martin; Bogani, Lapo

    2014-05-01

    The far-infrared optical transmission has been studied for two lanthanide-based single-chain magnets DyPhOPh and TbPhOPh in the frequency range between 3 and 80 cm-1. The spectra were acquired at temperatures between 2 and 80 K and magnetic fields up to 6 T. Based on their magnetic field dependence in DyPhOPh two of the observed absorption lines are identified as transitions inside the crystal field split Dy3+ ground multiplet 6H15/2, coupled to the neighboring spins. In TbPhOPh one transition was observed inside the crystal-field-split Tb3+ ground multiplet 7F6. The results allow a spectroscopic investigation of the role of single-ion anisotropy and exchange in Glauber dynamics.

  7. Generation of pulsed far-infrared radiation and its application for far-infrared time-resolved spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, Yasuhiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering

    1996-07-01

    So-called time-resolved spectroscopy technique has been used from old time as the means for studying the dynamic optical property, light-induced reaction and so on of matters. As an example, there is the method called pump and probe, and here, the wavelength of this probe light is the problem. If the object energy region is limited to about 0.1 eV, fast time-resolved spectroscopy is feasible relatively easily. However, energy region is extended to low energy region, the light source which is available as the pulsed probe light having sufficient intensity is limited. In this paper, the attempt of time-resolved spectroscopy utilizing coherent radiation, which has ended in failure, and the laser pulse-induced far-infrared radiation which can be utilized as new far-infrared probe light are reported. The reason why far-infrared radiation is used is explained. The attempt of time-resolved spectroscopy using NaCl crystals is reported on the equipment, the method of measuring absorption spectra and the results. Laser pulse-induced far-infrared radiation and the method of generating it are described. The multi-channel detector for far-infrared radiation which was made for trial is shown. (K.I.)

  8. Radio continuum, far infrared and star formation

    International Nuclear Information System (INIS)

    Wielebinski, R.; Wunderlich, E.; Klein, U.; Hummel, E.

    1987-01-01

    A very tight correlation was found between the radio emission and the far infrared emission from galaxies. This has been found for various samples of galaxies and is explained in terms of recent star formation. The tight correlation would imply that the total radio emission is a good tracer of star formation. The correlation between the radio power at 5 GHz and the far infrared luminosity is shown. The galaxies are of various morphological types and were selected from the various IRAS circulars, hence the sample is an infrared selected sample. The far infrared luminosities were corrected for the dust temperature. This is significant because it decreases the dispersion in the correlation

  9. Far infrared peculiar behavior of quasars

    International Nuclear Information System (INIS)

    Liu Yulin; Liu Jiying

    1988-09-01

    Many quasars possibly have nebulous envelopes with far infrared radiation. These nebulosities may be similar to fuzz in the optical region in morphology. These quasars have many properties in common. (author). Refs, 3 figs

  10. Josephson effect far-infrared detector

    International Nuclear Information System (INIS)

    Shapiro, S.

    1971-01-01

    Four Josephson effect schemes for detection of far-infrared radiation are reviewed: Video broad-band detection, regenerative detection, conventional mixing for monochromatic signals, and self-mixing or frequency conversion. (U.S.)

  11. Far-infrared spectroscopy of HII regions

    International Nuclear Information System (INIS)

    Emery, R.J.; Kessler, M.F.

    1984-01-01

    Interest has developed rapidly in the astrophysics associated with far-infrared line emission from ionised regions, following the development of spectroscopic instruments and observing facilities appropriate to those wavelengths. Far-infrared observations and their interpretation are now at the stage where the need for specific developments in theoretical and laboratory work have been identified. The need is also apparent for the development of models dealing with more realistic astrophysical situations. (Auth.)

  12. Far-infrared observations of globules

    International Nuclear Information System (INIS)

    Keene, J.

    1981-01-01

    Observations of far-infrared emission from nine globules are presented. The intensity and uniformity of the emission confirm that the heat source is the interstellar radiation field. Spectra of B133 and B335 are presented; they are consistent with optically thin thermal emission from dust with temperature 13--16 K. The emissivity of the grains must fall as fast as lambda -2 for lambda>500 μm. The temperature and intensity of B335 are used to calculate the ratio of visual extinction to far-infrared emission frequency

  13. Electromagnetic modelling of a space-borne far-infrared interferometer

    Science.gov (United States)

    Donohoe, Anthony; O'Sullivan, Créidhe; Murphy, J. Anthony; Bracken, Colm; Savini, Giorgio; Pascale, Enzo; Ade, Peter; Sudiwala, Rashmi; Hornsby, Amber

    2016-02-01

    In this paper I will describe work done as part of an EU-funded project `Far-infrared space interferometer critical assessment' (FISICA). The aim of the project is to investigate science objectives and technology development required for the next generation THz space interferometer. The THz/FIR is precisely the spectral region where most of the energy from stars, exo-planetary systems and galaxy clusters deep in space is emitted. The atmosphere is almost completely opaque in the wave-band of interest so any observation that requires high quality data must be performed with a space-born instrument. A space-borne far infrared interferometer will be able to answer a variety of crucial astrophysical questions such as how do planets and stars form, what is the energy engine of most galaxies and how common are the molecule building blocks of life. The FISICA team have proposed a novel instrument based on a double Fourier interferometer that is designed to resolve the light from an extended scene, spectrally and spatially. A laboratory prototype spectral-spatial interferometer has been constructed to demonstrate the feasibility of the double-Fourier technique at far infrared wavelengths (0.15 - 1 THz). This demonstrator is being used to investigate and validate important design features and data-processing methods for future instruments. Using electromagnetic modelling techniques several issues related to its operation at long baselines and wavelengths, such as diffraction, have been investigated. These are critical to the design of the concept instrument and the laboratory testbed.

  14. Far infrared studies of superconducting V3Si, Nb3Ge and Nb. Final report

    International Nuclear Information System (INIS)

    Perkowitz, S.

    1985-01-01

    Far infrared spectroscopy between 10 and 250 cm -1 is an effective probe of superconductivity because typical gap and phonon energies lie in this region. Between 1979 and 1985, this DOE contract supported far infrared research in homogeneous high-T/sub c/ superconductors and in granular superconductors. Results in both areas are summarized in this report

  15. Far infrared reflectivity study of ceramic superconductors

    International Nuclear Information System (INIS)

    Memon, A.; Khan, M.N.; Al-Dallal, S.; Tanner, D.B.; Porter, C.D.

    1992-01-01

    In this paper, the authors report on a study of the far-infrared reflectivity of mixed rare earths and lanthnides ceramic superconductors RBa 2 Cu 3 O 7 in the normal state. The authors' results show that the strength of the phonon modes is reduced when yttrium is partially replaced by gadolinium and europium. Also the critical temperature of these mixed materials is reduced as indicated by the four probe technique

  16. Synchrotron radiation in the Far-Infrared: Adsorbate-substrate vibrations and resonant interactions

    International Nuclear Information System (INIS)

    Hoffmann, F.M.; Williams, G.P.; Hirschmugl, C.J.; Chabal, Y.J.

    1991-01-01

    Synchrotron radiation in the Far Infrared offers the potential for a broadband source of high brightness and intensity. Recent development of a Far-Infrared Beamline at the NSLS in Brookhaven provides an unique high intensity source in the FIR spectral range (800-10 cm -1 ). This talk reviews its application to surface vibrational spectroscopy of low frequency adsorbate-substrate vibrations and resonant interactions on metal surfaces

  17. Observability of localized magnetoplasmons in quantum dots: Scrutinizing the eligibility of far-infrared, Raman, and electron-energy-loss spectroscopies

    Directory of Open Access Journals (Sweden)

    Manvir S. Kushwaha

    2016-03-01

    Full Text Available We investigate a one-component, quasi-zero dimensional, quantum plasma exposed to a parabolic potential and an applied magnetic field in the symmetric gauge. If the size of such a system as can be realized in the semiconducting quantum dots is on the order of the de-Broglie wavelength, the electronic and optical properties become highly tunable. Then the quantum size effects challenge the observation of many-particle phenomena such as the magneto-optical absorption, Raman intensity, and electron energy-loss spectrum. An exact analytical solution of the problem leads us to infer that these many-particle phenomena are, in fact, dictated by the generalized Kohn’s theorem (GKT in the long-wavelength limit. Maneuvering the confinement and/or the magnetic field furnishes the resonance energies capable of being explored with the FIR, Raman, and/or electron-energy-loss spectroscopy. This implies that either of these probes is competent in observing the localized magnetoplasmons in the system. As an application of the rigorous analytical diagnosis of the system, we have presented various pertinent single-particle, such as Fock-Darwin spectrum, Fermi energy, zigzag excitation spectrum, and magneto-optical transitions, and the many-particle phenomena, such as magneto-optical absorption, Raman intensity, and electron energy-loss probability. In the latter, the energy position of the resonance peaks is observed to be independent of the electron-electron interactions and hence of the number of electrons in the quantum dot in compliance with the GKT. It is found that both confinement potential and magnetic field play a decisive role in influencing the aforementioned many-particle phenomena. Specifically, increasing (decreasing the strength of the confining potential is found to be analogous to shrinking (expanding the size of the quantum dots and results into a blue (red shift in the respective spectra. Intensifying the magnetic field has two-fold effects in

  18. Observability of localized magnetoplasmons in quantum dots: Scrutinizing the eligibility of far-infrared, Raman, and electron-energy-loss spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Kushwaha, Manvir S. [Department of Physics and Astronomy, Rice University, P.O. Box 1892, Houston, Texas 77251 (United States)

    2016-03-15

    We investigate a one-component, quasi-zero dimensional, quantum plasma exposed to a parabolic potential and an applied magnetic field in the symmetric gauge. If the size of such a system as can be realized in the semiconducting quantum dots is on the order of the de-Broglie wavelength, the electronic and optical properties become highly tunable. Then the quantum size effects challenge the observation of many-particle phenomena such as the magneto-optical absorption, Raman intensity, and electron energy-loss spectrum. An exact analytical solution of the problem leads us to infer that these many-particle phenomena are, in fact, dictated by the generalized Kohn’s theorem (GKT) in the long-wavelength limit. Maneuvering the confinement and/or the magnetic field furnishes the resonance energies capable of being explored with the FIR, Raman, and/or electron-energy-loss spectroscopy. This implies that either of these probes is competent in observing the localized magnetoplasmons in the system. As an application of the rigorous analytical diagnosis of the system, we have presented various pertinent single-particle, such as Fock-Darwin spectrum, Fermi energy, zigzag excitation spectrum, and magneto-optical transitions, and the many-particle phenomena, such as magneto-optical absorption, Raman intensity, and electron energy-loss probability. In the latter, the energy position of the resonance peaks is observed to be independent of the electron-electron interactions and hence of the number of electrons in the quantum dot in compliance with the GKT. It is found that both confinement potential and magnetic field play a decisive role in influencing the aforementioned many-particle phenomena. Specifically, increasing (decreasing) the strength of the confining potential is found to be analogous to shrinking (expanding) the size of the quantum dots and results into a blue (red) shift in the respective spectra. Intensifying the magnetic field has two-fold effects in the resonance

  19. A high resolution helium atom scattering and far infrared study of the dynamics and the lateral potential energy surface of CO molecules chemisorbed on Cu(001)

    International Nuclear Information System (INIS)

    Graham, A.P.; Hofmann, F.; Toennies, J.P.; Williams, G.P.; Hirschmugl, C.J.; Ellis, J.

    1998-01-01

    Inelastic helium scattering (HAS) and infrared reflection adsorption spectroscopy (IRAS) have been used to measure the isotope shifts of the frequencies of both the parallel and perpendicular frustrated translation modes, as well as the frustrated rotation mode of CO molecules at on top sites on Cu(001). The measured isotope shifts for four different isotopomers indicates a significant rotational contribution to the parallel frustrated translation (T-mode), where the vibrational amplitude of the oxygen atom is significantly larger than for the carbon atom. Conversely, for the frustrated rotation the vibrational amplitude of the carbon atom was observed to be larger than for the oxygen atom. At surface temperatures above T s =100 K a careful analysis of the peak shape of the HAS quasielastic peak shows a small broadening, which is attributed to a rapid diffusion of the CO molecules. The measured dynamic diffusion barrier of 31±10 meV is compatible with the shape of the potential at the on-top site and makes it possible to extend the potential energy surface to the region between the on-top sites. copyright 1998 American Institute of Physics

  20. FAR-INFRARED EXTINCTION MAPPING OF INFRARED DARK CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Wanggi [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Tan, Jonathan C. [Departments of Astronomy and Physics, University of Florida, Gainesville, FL 32611 (United States)

    2014-01-10

    Progress in understanding star formation requires detailed observational constraints on the initial conditions, i.e., dense clumps and cores in giant molecular clouds that are on the verge of gravitational instability. Such structures have been studied by their extinction of near-infrared and, more recently, mid-infrared (MIR) background light. It has been somewhat more of a surprise to find that there are regions that appear as dark shadows at far-infrared (FIR) wavelengths as long as ∼100 μm! Here we develop analysis methods of FIR images from Spitzer-MIPS and Herschel-PACS that allow quantitative measurements of cloud mass surface density, Σ. The method builds on that developed for MIR extinction mapping by Butler and Tan, in particular involving a search for independently saturated, i.e., very opaque, regions that allow measurement of the foreground intensity. We focus on three massive starless core/clumps in the Infrared Dark Cloud (IRDC) G028.37+00.07, deriving mass surface density maps from 3.5 to 70 μm. A by-product of this analysis is the measurement of the spectral energy distribution of the diffuse foreground emission. The lower opacity at 70 μm allows us to probe to higher Σ values, up to ∼1 g cm{sup –2} in the densest parts of the core/clumps. Comparison of the Σ maps at different wavelengths constrains the shape of the MIR-FIR dust opacity law in IRDCs. We find that it is most consistent with the thick ice mantle models of Ossenkopf and Henning. There is tentative evidence for grain ice mantle growth as one goes from lower to higher Σ regions.

  1. The Intrinsic Far-infrared Continua of Type-1 Quasars

    Energy Technology Data Exchange (ETDEWEB)

    Lyu, Jianwei; Rieke, George H., E-mail: jianwei@email.arizona.edu [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

    2017-06-01

    The range of currently proposed active galactic nucleus (AGN) far-infrared templates results in uncertainties in retrieving host galaxy information from infrared observations and also undermines constraints on the outer part of the AGN torus. We discuss how to test and reconcile these templates. Physically, the fraction of the intrinsic AGN IR-processed luminosity compared with that from the central engine should be consistent with the dust-covering factor. In addition, besides reproducing the composite spectral energy distributions (SEDs) of quasars, a correct AGN IR template combined with an accurate library of star-forming galaxy templates should be able to reproduce the IR properties of the host galaxies, such as the luminosity-dependent SED shapes and aromatic feature strengths. We develop tests based on these expected behaviors and find that the shape of the AGN intrinsic far-IR emission drops off rapidly starting at ∼20 μ m and can be matched by an Elvis et al.-like template with a minor modification. Despite the variations in the near- to mid-IR bands, AGNs in quasars and Seyfert galaxies have remarkably similar intrinsic far-IR SEDs at λ ∼ 20–100 μ m, suggesting a similar emission character of the outermost region of the circumnuclear torus. The variations of the intrinsic AGN IR SEDs among the type-1 quasar population can be explained by the changing relative strengths of four major dust components with similar characteristic temperatures, and there is evidence for compact AGN-heated dusty structures at sub-kiloparsec scales in the far-IR.

  2. FAR-INFRARED EXTINCTION MAPPING OF INFRARED DARK CLOUDS

    International Nuclear Information System (INIS)

    Lim, Wanggi; Tan, Jonathan C.

    2014-01-01

    Progress in understanding star formation requires detailed observational constraints on the initial conditions, i.e., dense clumps and cores in giant molecular clouds that are on the verge of gravitational instability. Such structures have been studied by their extinction of near-infrared and, more recently, mid-infrared (MIR) background light. It has been somewhat more of a surprise to find that there are regions that appear as dark shadows at far-infrared (FIR) wavelengths as long as ∼100 μm! Here we develop analysis methods of FIR images from Spitzer-MIPS and Herschel-PACS that allow quantitative measurements of cloud mass surface density, Σ. The method builds on that developed for MIR extinction mapping by Butler and Tan, in particular involving a search for independently saturated, i.e., very opaque, regions that allow measurement of the foreground intensity. We focus on three massive starless core/clumps in the Infrared Dark Cloud (IRDC) G028.37+00.07, deriving mass surface density maps from 3.5 to 70 μm. A by-product of this analysis is the measurement of the spectral energy distribution of the diffuse foreground emission. The lower opacity at 70 μm allows us to probe to higher Σ values, up to ∼1 g cm –2 in the densest parts of the core/clumps. Comparison of the Σ maps at different wavelengths constrains the shape of the MIR-FIR dust opacity law in IRDCs. We find that it is most consistent with the thick ice mantle models of Ossenkopf and Henning. There is tentative evidence for grain ice mantle growth as one goes from lower to higher Σ regions

  3. Far-infrared spectra of acetanilide revisited

    Science.gov (United States)

    Spire, A.; Barthes, M.; Kellouai, H.; De Nunzio, G.

    2000-03-01

    A new investigation of the temperature dependence of the far-infrared spectra of acetanilide and some isotopomers is presented. Four absorption bands are considered at 31, 42, 64, and 80 cm-1, and no significant change of their integrated intensity is observed when reducing the temperature. The temperature induced frequency shift values and other properties of these bands are consistent with an assignment as anharmonic lattice phonons. These results rule out the assignment of the 64, 80, and 106 cm-1 bands as normal modes of the polaronic excitation, as previously suggested.

  4. Drying watery wheat grains by far infrared

    International Nuclear Information System (INIS)

    Suda, K.; Murata, K.; Hara, M.

    2004-01-01

    Summary A far infrared dryer was experimented to dry wheat grains for high performance and cost reduction. It is more efficient than a circulating dryer reducing drying time by 20% and fuel consumption by 20 - 30%. Whereas it takes more time and more fuel, when the drying rate is set at 1%/h. Moreover, on condition that the average drying rate is lower, it could decrease the rate of green wheat grains up to 3%. But green wheat grains did not disappear at all on the condition

  5. Reststrahlen Band Optics for the Advancement of Far-Infrared Optical Architecture

    Science.gov (United States)

    Streyer, William Henderson

    . Computational models of the emission indicated the samples had significantly higher power efficiency than a blackbody at the same temperature in the same wavelength band. Chapter 5 presents selective thermal emission in the far-infrared from samples of patterned gallium phosphide. The selective absorption of the samples occurs in the material's Reststrahlen band and can be attributed to surface phonon polariton modes. The surfaces of the samples were grated via wet etching to provide the additional momentum necessary for free space photons to couple into and out of the surface phonon polariton modes. Upon heating the samples, selective thermal emission of the surface phonon polariton modes was observed. Chapter 6 investigates a potential means of linking lattice vibrations to free space photons. Lightly doped films of gallium arsenide were grown by molecular beam epitaxy and wet etched with 1D gratings. The light doping served to modify the material's intrinsic permittivity and extend the region of its Reststrahlen band. Though the extension of the region with negative real permittivity was small, it extended beyond the longitudinal optical phonon energy of the material, which stands as the high energy boundary of the unmodified material's Reststrahlen band. Hybrid surface polariton modes were observed at energies near the longitudinal optical phonon energy where they are not supported on the surface of the intrinsic material -- offering a potential bridge between bulk optical phonon populations and free space photons. Chapter 7 presents preliminary results exploring the prospect of exploiting an absorption resonance known as the Berreman mode as a mechanism to link optical phonons to free space photons. The Berreman mode is a strong absorption resonance that occurs near the longitudinal optical phonon energy at moderate angles of incidence in polar semiconductors. Preliminary results demonstrate selective thermal emission consistent with the expected spectral position of the

  6. Far infrared spectroscopy of H II regions

    International Nuclear Information System (INIS)

    Ward, D.B.

    1976-01-01

    A fully liquid helium cooled grating spectrometer has been developed for far infrared observations from the NASA Lear Jet. This instrument has been used in observations of the galactic HII regions M42 and M17. The instrument is described, and the results of various performance tests and calibrations are presented. The methods employed in observations from the Lear Jet are described, and the data analysis procedures are discussed. The results of a search for the (O III) 88.16 micron fine structure line are presented. The intensity of the line in M17 is reported, and an upper limit given for the intensity in M42. These results are compared with theoretical predictions, and future applications of infrared line observations are discussed. Coarse resolution spectra of M42 and M17 from 45 to 115 microns are also presented. The emission from M42 is shown to be a very smooth function of wavelength, closely fitting the wavelength dependence of a 105 0 K graybody. The spectrum of M17 is very different, having a bump at approximately 75 microns and a general far infrared excess. The observed spectrum is compared to the predictions of models for M17

  7. Coherent atomic and molecular spectroscopy in the far infrared

    International Nuclear Information System (INIS)

    Inguscio, M.

    1988-01-01

    Recent advances in far infrared spectroscopy of atoms (fine structure transitions) and molecules (rotational transitions) are reviewed. Results obtained by means of Laser Magnetic Resonance, using fixed frequency lasers, and Tunable Far Infrared spectrometers are illustrated. The importance of far infrared spectroscopy for several fields, including astrophysics, atmospheric physics, atomic structure and metology, is discussed. (orig.)

  8. Far-infrared luminosities of Markarian starburst galaxies

    International Nuclear Information System (INIS)

    Deutsch, L.K.; Willner, S.P.

    1986-01-01

    Total far-infrared luminosities have been calculated from measured IRAS fluxes for a sample of optically selected galaxies and for a comparison sample of spiral galaxies. The starburst galaxies are notably more luminous in the far-infrared and have higher dust color temperatures than the comparison galaxies. The far-infrared light dominates the total luminosity of the starburst galaxies, and a significant amount of dust must be present. The far-infrared emission correlates well with total blue luminosity, nuclear blue luminosity, and nuclear H-alpha luminosity. The dust that produces the far-infrared light is probably heated predominantly by B rather than by O stars. 30 references

  9. Kinetic inductance detectors for far-infrared spectroscopy

    International Nuclear Information System (INIS)

    Barlis, A.; Aguirre, J.; Stevenson, T.

    2016-01-01

    The star formation mechanisms at work in the early universe remain one of the major unsolved problems of modern astrophysics. Many of the luminous galaxies present during the period of peak star formation (at redshift of about 2.5) were heavily enshrouded in dust, which makes observing their properties difficult at optical wavelengths. However, many spectral lines exist at far-infrared wavelengths that serve as tracers of star formation. Here, we describe a detector system suitable for a balloon-borne spectroscopic intensity mapping experiment at far-infrared wavelengths. The system uses lumped-element kinetic inductance detectors (KIDs), which have the potential to achieve high sensitivity and low noise levels. KIDs consist of separate capacitive and inductive elements, and use the inductive element as the radiation absorber. We describe the design considerations, fabrication process, and readout scheme for a prototype LEKID array of 1600 pixels. - Highlights: • We describe a concept for a balloon-borne telescope for far-IR wavelengths. • Telescope would use high-sensitivity kinetic inductance detectors. • Design considerations and fabrication process for prototype detectors.

  10. Kinetic inductance detectors for far-infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Barlis, A., E-mail: abarlis@physics.upenn.edu [University of Pennsylvania Department of Physics and Astronomy, Philadelphia, Pennsylvania (United States); Aguirre, J. [University of Pennsylvania Department of Physics and Astronomy, Philadelphia, Pennsylvania (United States); Stevenson, T. [NASA Goddard Space Flight Center, Greenbelt, Maryland (United States)

    2016-07-11

    The star formation mechanisms at work in the early universe remain one of the major unsolved problems of modern astrophysics. Many of the luminous galaxies present during the period of peak star formation (at redshift of about 2.5) were heavily enshrouded in dust, which makes observing their properties difficult at optical wavelengths. However, many spectral lines exist at far-infrared wavelengths that serve as tracers of star formation. Here, we describe a detector system suitable for a balloon-borne spectroscopic intensity mapping experiment at far-infrared wavelengths. The system uses lumped-element kinetic inductance detectors (KIDs), which have the potential to achieve high sensitivity and low noise levels. KIDs consist of separate capacitive and inductive elements, and use the inductive element as the radiation absorber. We describe the design considerations, fabrication process, and readout scheme for a prototype LEKID array of 1600 pixels. - Highlights: • We describe a concept for a balloon-borne telescope for far-IR wavelengths. • Telescope would use high-sensitivity kinetic inductance detectors. • Design considerations and fabrication process for prototype detectors.

  11. Stimulated transition radiation in the far-infrared

    International Nuclear Information System (INIS)

    Settakorn, C.; Hernandez, M.; Wiedemann, H.

    1997-08-01

    Stimulated transition radiation is generated by recycling coherent far-infrared light pulses of transition radiation in a special cavity. The cavity length is designed to be adjustable. At specific intervals the light of a previous bunch coincides at the radiator with the arrival of a subsequent bunch. In this situation, the external electromagnetic field stimulates the emission of higher intensity transition radiation. It is expected that the extracted energy from the cavity will be about 17 times more than would be possible without recycling

  12. Early results from the Far Infrared Absolute Spectrophotometer (FIRAS)

    Science.gov (United States)

    Mather, J. C.; Cheng, E. S.; Shafer, R. A.; Eplee, R. E.; Isaacman, R. B.; Fixsen, D. J.; Read, S. M.; Meyer, S. S.; Weiss, R.; Wright, E. L.

    1991-01-01

    The Far Infrared Absolute Spectrophotometer (FIRAS) on the Cosmic Background Explorer (COBE) mapped 98 percent of the sky, 60 percent of it twice, before the liquid helium coolant was exhausted. The FIRAS covers the frequency region from 1 to 100/cm with a 7 deg angular resolution. The spectral resolution is 0.2/cm for frequencies less than 20/cm and 0.8/cm for higher frequencies. Preliminary results include: a limit on the deviations from a Planck curve of 1 percent of the peak brightness from 1 to 20/cm, a temperature of 2.735 +/- 0.06 K, a limit on the Comptonization parameter y of 0.001, on the chemical potential parameter mu of 0.01, a strong limit on the existence of a hot smooth intergalactic medium, and a confirmation that the dipole anisotropy spectrum is that of a Doppler shifted blackbody.

  13. High resolution spectroscopy in the microwave and far infrared

    Science.gov (United States)

    Pickett, Herbert M.

    1990-01-01

    High resolution rotational spectroscopy has long been central to remote sensing techniques in atmospheric sciences and astronomy. As such, laboratory measurements must supply the required data to make direct interpretation of data for instruments which sense atmospheres using rotational spectra. Spectral measurements in the microwave and far infrared regions are also very powerful tools when combined with infrared measurements for characterizing the rotational structure of vibrational spectra. In the past decade new techniques were developed which have pushed high resolution spectroscopy into the wavelength region between 25 micrometers and 2 mm. Techniques to be described include: (1) harmonic generation of microwave sources, (2) infrared laser difference frequency generation, (3) laser sideband generation, and (4) ultrahigh resolution interferometers.

  14. Tunable Far Infrared Studies in Support of Stratospheric Measurements

    Science.gov (United States)

    Chance, Kelly V.; Park, K.; Nolt, I. G.; Evenson, K. M.

    2001-01-01

    determined from Stark effect measurements; exceptions include some molecules with large vibration-rotation interactions (NO2) and internal motions (H2O2 above the lowest torsional state). The line parameters that are still the least well determined are pressure broadening coefficients, and their temperature coefficients, These are strongly dependent on the quantum states involved in the transitions, in a way that is much more complex than the simple projection by directional cosine matrix elements involved in determination of rotational line strengths from static dipole moments. The following molecules have now been measured or detected in the atmosphere using far infrared and millimeter-wave emission spectroscopy from balloon- and satellite-borne spectrometers: OH, HO2, H2O (including minor isotopomers and hot band lines), H2O2, O3P, O2 (including minor isotopomers), O3 (including minor isotopomers and hot band lines), HOCl, HCl, HF, HBr, CIO, CO, CO2, N2O, NO2, N2O5, HNO3, ClNO3, and HCN. Many of these species have spectral lines that are saturated in stratospheric spectra. In these cases, the measured line equivalent widths are proportional to (line strength x Lorentz width) (exp 1/2) so that the pressure broadening coefficients are as important as the line intensities in determining concentration profiles. Interpretation of field measurements for these species have required ongoing measurement programs of pressure broadening measurements. Other species (HO2, HGCl, H2O2, HBr, and NO2, as examples) have required further line position studies in order to fully analyze the field measurements.

  15. Dust properties around evolved stars from far-infrared size limits

    International Nuclear Information System (INIS)

    Harvey, P.M.; Lester, D.F.; Brock, D.; Joy, M.

    1991-01-01

    High angular resolution far-infrared scans were obtained of six stars surrounded by circumstellar dust shells believed to result from mass loss by the central star. None of the dust shells was clearly resolved at either 50 or 100 microns; the upper limits are in the range 4 to 10 arcsec. These size limits place constraints on the far-IR dust emissivity and dust density distribution. For one of the objects, AFGL 2343, larger than normal grains are almost certainly required. For several other stars, the size limits are much more consistent with dust having an emissivity law no steeper than 1/lambda in the 1-100-micron spectral region. For IRC + 10216, an earlier suggestion is confirmed that, assuming reasonable grain properties, a smooth radial dust distribution is not consistent with the scans and the energy distribution of the object. 29 refs

  16. Far-infrared constraints on the contamination by dust-obscured galaxies of high-z dropout searches.

    OpenAIRE

    Boone, F.; Schaerer, D.; Pelló, R.; Lutz, D.; Weiss, A.; Egami, E.; Smail, I.; Rex, M.; Rawle, T.; Ivison, R.; Laporte, N.; Beelen, A.; Combes, F.; Blain, A.W.; Richard, J.

    2011-01-01

    The spectral energy distributions (SED) of dusty galaxies at intermediate redshift may look similar to very high-redshift galaxies in the optical/near infrared (NIR) domain. This can lead to the contamination of high-redshift galaxy searches based on broad-band optical/NIR photometry by lower redshift dusty galaxies because both kind of galaxies cannot be distinguished. The contamination rate could be as high as 50%. This work shows how the far-infrared (FIR) domain can help to recognize like...

  17. Far infrared supplement: Catalog of infrared observations, second edition

    International Nuclear Information System (INIS)

    Gezari, D.Y.; Schmitz, M.; Mead, J.M.

    1988-08-01

    The Far Infrared Supplement: Catalog of Infrared Observations summarizes all infrared astronomical observations at far infrared wavelengths (5 to 1000 microns) published in the scientific literature from 1965 through 1986. The Supplement list contain 25 percent of the observations in the full Catalog of Infrared Observations (CIO), and essentially eliminates most visible stars from the listings. The Supplement is thus more compact than the main catalog, and is intended for easy reference during astronomical observations. The Far Infrared Supplement (2nd Edition) includes the Index of Infrared Source Positions and the Bibliography of Infrared Astronomy for the subset of far infrared observations listed

  18. A study of far-infrared Michelson interferometry based on fast plasma scanning

    International Nuclear Information System (INIS)

    Bartlett, D.V.; Hewitt, G.L.; Robinson, L.C.; Tait, G.D.

    1976-02-01

    Fast far-infrared multiplex spectroscopy based on a plasma-scanned Michelson interferometer is studied. Our experiments show that the interferometer has sub-millisecond time response and high spectral resolving power. In addition to a description of the experimental performance of the interferometer, we develop and discuss two different methods of interferogram inversion. (author)

  19. A study of far-infrared Michelson interferometry based on fast plasma scanning

    International Nuclear Information System (INIS)

    Bartlett, D.V.; Hewitt, R.G.L.; Robinson, L.C.; Tait, G.D.

    1977-01-01

    Fast far infrared (FIR) muliplex spectroscopy based on a plasma-scanned Michelson interferometer is studied. Experiments show that the interferometer has sub-millisecond time response and high spectral resolving power. In addition to the description of the experimental performance of the interferometer, two different methods of interferogram inversion are developed and discussed. (author)

  20. Far-infrared irradiation drying behavior of typical biomass briquettes

    International Nuclear Information System (INIS)

    Chen, N.N.; Chen, M.Q.; Fu, B.A.; Song, J.J.

    2017-01-01

    Infrared radiation drying behaviors of four typical biomass briquettes (populus tomentosa leaves, cotton stalk, spent coffee grounds and eucalyptus bark) were investigated based on a lab-scale setup. The effect of radiation source temperatures (100–200 °C) on the far-infrared drying kinetics and heat transfer of the samples was addressed. As the temperature went up from 100 °C to 200 °C, the time required for the four biomass briquettes drying decreased by about 59–66%, and the average values of temperature for the four biomass briquettes increased by about 33–39 °C, while the average radiation heat transfer fluxes increased by about 3.3 times (3.7 times only for the leaves). The specific energy consumptions were 0.622–0.849 kW h kg"−"1. The Modified Midilli model had the better representing for the moisture ratio change of the briquettes. The values of the activation energy for the briquettes in the first falling rate stage were between 20.35 and 24.83 kJ mol"−"1, while those in the second falling rate stage were between 17.89 and 21.93 kJ mol"−"1. The activation energy for the eucalyptus bark briquette in two falling rate stages was the least one, and that for the cotton stalk briquette was less than that for the rest two briquettes. - Highlights: • Far infrared drying behaviors of four typical biomass briquettes were addressed. • The effect of radiation source temperatures on IR drying kinetics was stated. • Radiation heat transfer flux between the sample and heater was evaluated. • Midilli model had the better representing for the drying process of the samples.

  1. Far-infrared spectroscopic study of CeO{sub 2} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Popović, Z. V., E-mail: zoran.popovic@ipb.ac.rs; Grujić-Brojčin, M.; Paunović, N. [University of Belgrade, Center for Solid State Physics and New Materials, Institute of Physics (Serbia); Radonjić, M. M. [University of Belgrade, Scientific Computing Laboratory, Institute of Physics Belgrade (Serbia); Araújo, V. D.; Bernardi, M. I. B. [Universidade de São Paulo-USP, Instituto de Fisica (Brazil); Lima, M. M. de; Cantarero, A. [Universidad de Valencia, Instituto de Ciencia de Los Materiales (Spain)

    2015-01-15

    We present the far-infrared reflectivity spectra of 5 nm-sized pure and copper-doped Ce{sub 1−x}Cu{sub x}O{sub 2−y} (x = 0; 0.01 and 0.10) nanocrystals measured at room temperature in the 50–650 cm{sup −1} spectral range. Reflectivity spectra were analyzed using the factorized form of the dielectric function, which includes the phonon and the free carriers contribution. Four oscillators with TO energies of approximately 135, 280, 370, and 490 cm{sup −1} were included in the fitting procedure. These oscillators represent local maxima of the CeO{sub 2} phonon density of states, which is also calculated using the density functional theory. The lowest energy oscillator represents TA(L)/TA(X) phonon states, which become infrared-active E{sub u} modes at the L and X points of the Brillouin zone (BZ). The second oscillator originates from TO(Γ) phonon states. The oscillator at ∼400 cm{sup −1} originates from Raman mode phonon states, which at the L point of BZ also becomes infrared-active E{sub u} mode. The last oscillator describes phonons with dominantly LO(Γ) infrared mode character. The appearance of phonon density of states related oscillators, instead of single F{sub 2u}infrared-active mode in the far-infrared reflectivity spectra, is a consequence of the nanosized dimension of the CeO{sub 2} particles. The best fit spectra are obtained using the generalized Bruggeman model for inhomogeneous media, which takes into account the nanocrystal volume fraction and the pore shape.

  2. Far-infrared spectroscopic study of CeO2 nanocrystals

    Science.gov (United States)

    Popović, Z. V.; Grujić-Brojčin, M.; Paunović, N.; Radonjić, M. M.; Araújo, V. D.; Bernardi, M. I. B.; de Lima, M. M.; Cantarero, A.

    2015-01-01

    We present the far-infrared reflectivity spectra of 5 nm-sized pure and copper-doped Ce1- x Cu x O2- y ( x = 0; 0.01 and 0.10) nanocrystals measured at room temperature in the 50-650 cm-1 spectral range. Reflectivity spectra were analyzed using the factorized form of the dielectric function, which includes the phonon and the free carriers contribution. Four oscillators with TO energies of approximately 135, 280, 370, and 490 cm-1 were included in the fitting procedure. These oscillators represent local maxima of the CeO2 phonon density of states, which is also calculated using the density functional theory. The lowest energy oscillator represents TA(L)/TA(X) phonon states, which become infrared-active E u modes at the L and X points of the Brillouin zone (BZ). The second oscillator originates from TO(Γ) phonon states. The oscillator at 400 cm-1 originates from Raman mode phonon states, which at the L point of BZ also becomes infrared-active E u mode. The last oscillator describes phonons with dominantly LO(Γ) infrared mode character. The appearance of phonon density of states related oscillators, instead of single F 2uinfrared-active mode in the far-infrared reflectivity spectra, is a consequence of the nanosized dimension of the CeO2 particles. The best fit spectra are obtained using the generalized Bruggeman model for inhomogeneous media, which takes into account the nanocrystal volume fraction and the pore shape.

  3. Far-infrared spectroscopic study of CeO2 nanocrystals

    International Nuclear Information System (INIS)

    Popović, Z. V.; Grujić-Brojčin, M.; Paunović, N.; Radonjić, M. M.; Araújo, V. D.; Bernardi, M. I. B.; Lima, M. M. de; Cantarero, A.

    2015-01-01

    We present the far-infrared reflectivity spectra of 5 nm-sized pure and copper-doped Ce 1−x Cu x O 2−y (x = 0; 0.01 and 0.10) nanocrystals measured at room temperature in the 50–650 cm −1 spectral range. Reflectivity spectra were analyzed using the factorized form of the dielectric function, which includes the phonon and the free carriers contribution. Four oscillators with TO energies of approximately 135, 280, 370, and 490 cm −1 were included in the fitting procedure. These oscillators represent local maxima of the CeO 2 phonon density of states, which is also calculated using the density functional theory. The lowest energy oscillator represents TA(L)/TA(X) phonon states, which become infrared-active E u modes at the L and X points of the Brillouin zone (BZ). The second oscillator originates from TO(Γ) phonon states. The oscillator at ∼400 cm −1 originates from Raman mode phonon states, which at the L point of BZ also becomes infrared-active E u mode. The last oscillator describes phonons with dominantly LO(Γ) infrared mode character. The appearance of phonon density of states related oscillators, instead of single F 2u infrared-active mode in the far-infrared reflectivity spectra, is a consequence of the nanosized dimension of the CeO 2 particles. The best fit spectra are obtained using the generalized Bruggeman model for inhomogeneous media, which takes into account the nanocrystal volume fraction and the pore shape

  4. Airborne observations of far-infrared upwelling radiance in the Arctic

    Directory of Open Access Journals (Sweden)

    Q. Libois

    2016-12-01

    Full Text Available The first airborne measurements of the Far-InfraRed Radiometer (FIRR were performed in April 2015 during the panarctic NETCARE campaign. Vertical profiles of spectral upwelling radiance in the range 8–50 µm were measured in clear and cloudy conditions from the surface up to 6 km. The clear sky profiles highlight the strong dependence of radiative fluxes to the temperature inversion typical of the Arctic. Measurements acquired for total column water vapour from 1.5 to 10.5 mm also underline the sensitivity of the far-infrared greenhouse effect to specific humidity. The cloudy cases show that optically thin ice clouds increase the cooling rate of the atmosphere, making them important pieces of the Arctic energy balance. One such cloud exhibited a very complex spatial structure, characterized by large horizontal heterogeneities at the kilometre scale. This emphasizes the difficulty of obtaining representative cloud observations with airborne measurements but also points out how challenging it is to model polar clouds radiative effects. These radiance measurements were successfully compared to simulations, suggesting that state-of-the-art radiative transfer models are suited to study the cold and dry Arctic atmosphere. Although FIRR in situ performances compare well to its laboratory performances, complementary simulations show that upgrading the FIRR radiometric resolution would greatly increase its sensitivity to atmospheric and cloud properties. Improved instrument temperature stability in flight and expected technological progress should help meet this objective. The campaign overall highlights the potential for airborne far-infrared radiometry and constitutes a relevant reference for future similar studies dedicated to the Arctic and for the development of spaceborne instruments.

  5. HERSCHEL FAR-INFRARED SPECTRAL-MAPPING OF ORION BN/KL OUTFLOWS: SPATIAL DISTRIBUTION OF EXCITED CO, H{sub 2}O, OH, O, AND C{sup +} IN SHOCKED GAS

    Energy Technology Data Exchange (ETDEWEB)

    Goicoechea, Javier R.; Cernicharo, José; Cuadrado, Sara; Etxaluze, Mireya [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC). Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid (Spain); Chavarría, Luis [Centro de Astrobiología, CSIC-INTA, Ctra. de Torrejón a Ajalvir km 4, E-28850 Madrid (Spain); Neufeld, David A. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Vavrek, Roland [Herschel Science Center, ESA/ESAC, P.O. Box 78, Villanueva de la Cañada, E-28691 Madrid (Spain); Bergin, Edwin A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Encrenaz, Pierre [LERMA, UMR 8112 du CNRS, Observatoire de Paris, École Normale Supérieure, F-75014 Paris (France); Melnick, Gary J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 66, Cambridge, MA 02138 (United States); Polehampton, Edward, E-mail: jr.goicoechea@icmm.csic.es [RAL Space, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom)

    2015-01-20

    We present ∼2' × 2' spectral-maps of Orion Becklin-Neugebauer/Kleinmann-Low (BN/KL) outflows taken with Herschel at ∼12'' resolution. For the first time in the far-IR domain, we spatially resolve the emission associated with the bright H{sub 2} shocked regions ''Peak 1'' and ''Peak 2'' from that of the hot core and ambient cloud. We analyze the ∼54-310 μm spectra taken with the PACS and SPIRE spectrometers. More than 100 lines are detected, most of them rotationally excited lines of {sup 12}CO (up to J = 48-47), H{sub 2}O, OH, {sup 13}CO, and HCN. Peaks 1/2 are characterized by a very high L(CO)/L {sub FIR} ≈ 5 × 10{sup –3} ratio and a plethora of far-IR H{sub 2}O emission lines. The high-J CO and OH lines are a factor of ≈2 brighter toward Peak 1 whereas several excited H{sub 2}O lines are ≲50% brighter toward Peak 2. Most of the CO column density arises from T {sub k} ∼ 200-500 K gas that we associate with low-velocity shocks that fail to sputter grain ice mantles and show a maximum gas-phase H{sub 2}O/CO ≲ 10{sup –2} abundance ratio. In addition, the very excited CO (J > 35) and H{sub 2}O lines reveal a hotter gas component (T {sub k} ∼ 2500 K) from faster (v {sub S} > 25 km s{sup –1}) shocks that are able to sputter the frozen-out H{sub 2}O and lead to high H{sub 2}O/CO ≳ 1 abundance ratios. The H{sub 2}O and OH luminosities cannot be reproduced by shock models that assume high (undepleted) abundances of atomic oxygen in the preshock gas and/or neglect the presence of UV radiation in the postshock gas. Although massive outflows are a common feature in other massive star-forming cores, Orion BN/KL seems more peculiar because of its higher molecular luminosities and strong outflows caused by a recent explosive event.

  6. Far-infrared spectroscopy of neutral interstellar clouds

    International Nuclear Information System (INIS)

    Watson, D.M.

    1984-01-01

    A summary is presented of airborne observations of the far-infrared fine structure lines of neutral atomic oxygen and singly-ionized carbon, and of the far-infrared rotational lines of CO, OH, NH 3 and HD, together with a brief description of the analysis and interpretation of the spectra. The 'state of the art' in instrument performance and the prospects for improved sensitivity and resolution are also surveyed. (Auth.)

  7. Multichannel far-infrared phase imaging for fusion plasmas

    International Nuclear Information System (INIS)

    Young, P.E.; Neikirk, D.P.; Tong, P.P.; Rutledge, D.B.; Luhmann, N.C. Jr.

    1985-01-01

    A 20-channel far-infrared imaging interferometer system has been used to obtain single-shot density profiles in the UCLA Microtor tokamak. This system differs from conventional multichannel interferometers in that the phase distribution produced by the plasma is imaged onto a single, monolithic, integrated microbolometer linear detector array and provides significantly more channels than previous far-infrared interferometers. The system has been demonstrated to provide diffraction-limited phase images of dielectric targets

  8. Far-infrared fusion plasma diagnostics. Task IIIA. Final report

    International Nuclear Information System (INIS)

    Luhmann, N.C. Jr.

    1986-01-01

    The Task IIIA program at UCLA has been concerned with the development of innovative yet practical plasma diagnostic systems capable of providing detailed information essential to the success of the fusion program but not presently available within the fusion community. Historically, this has involved an initial development in the laboratory, followed by a test of feasibility on the Microtor tokamak prior to transfer of the technique/instrument to main line fusion devices. Strong emphasis has been placed upon the far-infrared (FIR) spectral region where novel diagnostic systems and technology have been developed and then distributed throughout the fusion program. The major diagnostics under development have been the measurement of plasma microturbulence and coherent modes via multichannel cw collective Thomson scattering, and the application of phase/polarization imaging techniques to provide accurate and detailed (>20 channel) electron density and current profiles not presently available using conventional methods. The eventual transfer of the above techniques to main line fusion devices is, of course, a major goal of the UCLA development program. The multichannel scattering development at UCLA was efficiently transferred to TEXT a few years ago. The apparatus has been employed to investigate the strong spectral and spatial asymmetries in the microturbulence uncovered through the unique multichannel and spatial scanning capabilities of the system. The scattering apparatus has also produced evidence for the ion pressure gradient driven eta/sub i/ modes thought responsible for anomalous transport in the edge regions of tokamak plasmas, as well as providing insight into the wave-wave coupling processes between various plasma modes

  9. A composite plot of far-infrared versus radio luminosity, and the origin of far-infrared luminosity in quasars

    International Nuclear Information System (INIS)

    Sopp, H.M.; Alexander, P.

    1991-01-01

    We have constructed a composite plot of far-infrared versus radioluminosity for late-type galaxies, Seyferts, quasars and radio galaxies. The most striking result is that the radio and far-infrared luminosities of radio-quiet quasars are correlated and follow the same correlation as normal star-forming galaxies and ultra-luminous infrared galaxies, whereas the radio-loud quasars have luminosities in both bands similar to those of radio galaxies. We conclude that the far-infrared emission from radio-quiet quasars is from star-forming host galaxies and not from active galactic nuclei. The far-infrared radio plot may be a powerful discriminator between host galaxy type. (author)

  10. Consideration of the Verleur model of far-infrared spectroscopy of ternary compounds

    International Nuclear Information System (INIS)

    Robouch, B. V.; Kisiel, A.; Sheregii, E. M.

    2001-01-01

    The clustering model proposed by Verleur and Barker [Phys. Rev. 149, 715 (1966)] to interpret far infrared data for face-centered-cubic ternary compounds is critically analyzed. It is shown that their approach, satisfactory for fitting some ternary compound spectral curves, is too restricted by its one-parameter β model to be able to describe preferences (with respect to a random distribution case) for the five tetrahedron configurations

  11. POLYCYCLIC AROMATIC HYDROCARBON FAR-INFRARED SPECTROSCOPY

    International Nuclear Information System (INIS)

    Boersma, C.; Mattioda, A. L.; Tielens, A. G. G. M.; Allamandola, L. J.; Bauschlicher, C. W. Jr; Ricca, A.; Peeters, E.

    2011-01-01

    sensitivity is not an issue, spectral contrast is maximized and the PAH population is only comprised of highly stable, compact symmetric PAHs, such as the members of the pyrene and coronene 'families' discussed in detail here.

  12. Polycyclic Aromatic Hydrocarbon Far-infrared Spectroscopy

    Science.gov (United States)

    Boersma, C.; Bauschlicher, C. W., Jr.; Ricca, A.; Mattioda, A. L.; Peeters, E.; Tielens, A. G. G. M.; Allamandola, L. J.

    2011-03-01

    sensitivity is not an issue, spectral contrast is maximized and the PAH population is only comprised of highly stable, compact symmetric PAHs, such as the members of the pyrene and coronene "families" discussed in detail here.

  13. Germanium blocked impurity band far infrared detectors

    International Nuclear Information System (INIS)

    Rossington, C.S.

    1988-04-01

    The infrared portion of the electromagnetic spectrum has been of interest to scientist since the eighteenth century when Sir William Herschel discovered the infrared as he measured temperatures in the sun's spectrum and found that there was energy beyond the red. In the late nineteenth century, Thomas Edison established himself as the first infrared astronomer to look beyond the solar system when he observed the star Arcturus in the infrared. Significant advances in infrared technology and physics, long since Edison's time, have resulted in many scientific developments, such as the Infrared Astronomy Satellite (IRAS) which was launched in 1983, semiconductor infrared detectors for materials characterization, military equipment such as night-vision goggles and infrared surveillance equipment. It is now planned that cooled semiconductor infrared detectors will play a major role in the ''Star Wars'' nuclear defense scheme proposed by the Reagan administration

  14. Biological activities caused by far-infrared radiation

    Science.gov (United States)

    Inoué, Shojiro; Kabaya, Morihiro

    1989-09-01

    Contrary to previous presumption, accumulated evidence indicates that far-infrared rays are biologically active. A small ceramic disk that emist far-infrared rays (4 16 μm) has commonly been applied to a local spot or a whole part of the body for exposure. Pioneering attempts to experimentally analyze an effect of acute and chronic radiation of far-infrared rays on living organisms have detected a growth-promoting effect in growing rats, a sleep-modulatory effect in freely behaving rats and an insomiac patient, and a blood circulation-enhancing effect in human skin. Question-paires to 542 users of far-infrared radiator disks embedded in bedelothes revealed that the majority of the users subjectively evaluated an improvement of their health. These effects on living organisms appear to be non-specifically triggered by an exposure to far-infrared rays, which eventually induce an increase in temperature of the body tissues or, more basically, an elevated motility of body fluids due to decrease in size of water clusters.

  15. Far infrared polarimetry of W51A and M42

    Energy Technology Data Exchange (ETDEWEB)

    Cudlip, W; Furniss, I; King, K J; Jennings, R E [University Coll., London (UK). Dept. of Physics and Astronomy

    1982-09-01

    A far infrared polarimeter has been designed for use with a balloon-borne telescope. It uses a rapidly rotating wire grid polarizer with the chopping secondary mirror of the telescope synchronized to the rate of rotation. Observations of M42 using this system show a far infrared polarization of 2.2 +- 0.4 per cent, nearly orthogonal to the near infrared polarization which is usually attributed to dust absorption. Observations of W51A show a much smaller value of the polarization of 0.8 +- 0.5 per cent.

  16. Synchrotron-based far-infrared spectroscopy of nickel tungstate

    International Nuclear Information System (INIS)

    Kalinko, A.; Kuzmin, A.; Roy, P.; Evarestov, R.A.

    2016-01-01

    Monoclinic antiferromagnetic NiWO 4 was studied by far-infrared (30-600 cm -1 ) absorption spectroscopy in the temperature range of 5-300 K using the synchrotron radiation from SOLEIL source. Two isomorphous CoWO 4 and ZnWO 4 tungstates were investigated for comparison. The phonon contributions in the far-infrared range of tungstates were interpreted using the first-principles spin-polarized linear combination of atomic orbital calculations. No contributions from magnetic excitations were found in NiWO 4 and CoWO 4 below their Neel temperatures down to 5 K.

  17. Far-infrared vibrational modes of DNA components studied by terahertz time-domain spectroscopy

    International Nuclear Information System (INIS)

    Fischer, B M; Walther, M; Jepsen, P Uhd

    2002-01-01

    The far-infrared dielectric function of a wide range of organic molecules is dominated by vibrations involving a substantial fraction of the atoms forming the molecule and motion associated with intermolecular hydrogen bond vibrations. Due to their collective nature such modes are highly sensitive to the intra- and intermolecular structure and thus provide a unique fingerprint of the conformational state of the molecule and effects of its environment. We demonstrate the use of terahertz time-domain spectroscopy (THz-TDS) for recording the far-infrared (0.5-4.0 THz) dielectric function of the four nucleobases and corresponding nucleosides forming the building blocks of deoxyribose nucleic acid (DNA). We observe numerous distinct spectral features with large differences between the molecules in both frequency-dependent absorption coefficient and index of refraction. Assisted by results from density-functional calculations we interpret the origin of the observed resonances as vibrations of hydrogen bonds between the molecules

  18. Modeling the HD 32297 Debris Disk With Far-Infrared Herschel Data

    Science.gov (United States)

    Donaldson, J.K.; Lebreton, J.; Roberge, A.; Augereau, J.-C.; Krivov, A. V.

    2013-01-01

    HD 32297 is a young A-star (approx. 30 Myr) 112 pc away with a bright edge-on debris disk that has been resolved in scattered light. We observed the HD 32297 debris disk in the far-infrared and sub-millimeter with the Herschel Space Observatory PACS and SPIRE instruments, populating the spectral energy distribution (SED) from 63 to 500 micron..We aimed to determine the composition of dust grains in the HD 32297 disk through SED modeling, using geometrical constraints from the resolved imaging to break the degeneracies inherent in SED modeling. We found the best fitting SED model has two components: an outer ring centered around 110 AU, seen in the scattered light images, and an inner disk near the habitable zone of the star. The outer disk appears to be composed of grains>2 micron consisting of silicates, carbonaceous material, and water ice with an abundance ratio of 1:2:3 respectively and 90% porosity. These grains appear consistent with cometary grains, implying the underlying planetesimal population is dominated by comet-like bodies. We also discuss the 3.7 sigma detection of [C ii] emission at 158 micron with the Herschel PACS instrument, making HD 32297 one of only a handful of debris disks with circumstellar gas detected

  19. MID- AND FAR-INFRARED PROPERTIES OF A COMPLETE SAMPLE OF LOCAL ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Ichikawa, Kohei; Ueda, Yoshihiro; Terashima, Yuichi; Oyabu, Shinki; Gandhi, Poshak; Nakagawa, Takao; Matsuta, Keiko

    2012-01-01

    We investigate the mid- (MIR) to far-infrared (FIR) properties of a nearly complete sample of local active galactic nuclei (AGNs) detected in the Swift/Burst Alert Telescope (BAT) all-sky hard X-ray (14-195 keV) survey, based on the cross correlation with the AKARI infrared survey catalogs complemented by those with Infrared Astronomical Satellite and Wide-field Infrared Survey Explorer. Out of 135 non-blazer AGNs in the Swift/BAT nine-month catalog, we obtain the MIR photometric data for 128 sources either in the 9, 12, 18, 22, and/or 25 μm band. We find good correlation between their hard X-ray and MIR luminosities over three orders of magnitude (42 λ (9, 18 μm) < 45), which is tighter than that with the FIR luminosities at 90 μm. This suggests that thermal emission from hot dusts irradiated by the AGN emission dominate the MIR fluxes. Both X-ray unabsorbed and absorbed AGNs follow the same correlation, implying isotropic infrared emission, as expected in clumpy dust tori rather than homogeneous ones. We find excess signals around 9 μm in the averaged infrared spectral energy distribution from heavy obscured 'new type' AGNs with small scattering fractions in the X-ray spectra. This could be attributed to the polycyclic aromatic hydrocarbon emission feature, suggesting that their host galaxies have strong starburst activities.

  20. Far-infrared laser interferometry measurements on the STP-3(M) reversed-field pinch

    International Nuclear Information System (INIS)

    Kubota, Shigeyuki; Nagatsu, Masaaki; Tsukishima, Takashige; Arimoto, Hideki; Sato, Koichi; Matsuoka, Akio.

    1993-09-01

    Far-infrared laser interferometry at 432 μm was carried out on the STP-3(M) reversed-field pinch. Measurements along two vertical chords showed a change from a parabolic-like to a flat-like electron density profile after field reversal. A density profile inversion and a correlated toroidal magnetic flux perturbation were also observed during the transition from the current rising to the current decay phase. Measurements of electron density fluctuations indicated relative fluctuation levels of ∼10% for both chords during the current rising phase and ∼5% and ∼15% during the current decay phase for the central and outer chords, respectively. Spectral analysis showed a ∼30 kHz mode consistent with poloidal mode number m=0 magnetic fluctuations, and a ∼90 kHz mode localized to the outer region of the plasma, which was strongly excited during the current decay phase and may be connected to particle and energy transport in STP-3(M). (author)

  1. Spectrophotometry in the far infrared. Optical and Hertzian processes

    International Nuclear Information System (INIS)

    Coste, Andre

    1968-01-01

    After a general study of problems related to instrumental spectroscopy in the far infrared, this research thesis examines the theory and technique of construction of slit spectrometers. The author then studied the possibilities to increase brightness and resolution using Fabry-Perot interferometers, and the Fourier transform interferential spectrometry, and finally addressed methods used with micro-waves

  2. Far-Infrared Absorption of PbSe Nanorods

    KAUST Repository

    Hyun, Byung-Ryool; Bartnik, A. C.; Koh, Weon-kyu; Agladze, N. I.; Wrubel, J. P.; Sievers, A. J.; Murray, Christopher B.; Wise, Frank W.

    2011-01-01

    Measurements of the far-infrared absorption spectra of PbSe nanocrystals and nanorods are presented. As the aspect ratio of the nanorods increases, the Fröhlich sphere resonance splits into two peaks. We analyze this splitting with a classical

  3. Progress in far-infrared spectroscopy: Approximately 1890 to 1970

    Science.gov (United States)

    Mitsuishi, Akiyoshi

    2014-03-01

    The history of far-infrared spectroscopy from its beginning to around 1970 is reviewed. Before World War II, the size of the community investigating this topic was limited. During this period, in particular before 1925, about 90% of the papers were published by H. Rubens and his co-workers in Germany. One or two researchers from the US joined the Rubens group per year from 1890 to the beginning of 1910. During the next year or two, some researchers joined M. Czerny, who is seen as the successor of Rubens. After World War II, far-infrared techniques progressed further in the US, which did not suffer damage during the war. The advanced techniques of far-infrared grating spectroscopy were transferred from the US (R. A. Oetjen) to Japan (H. Yoshinaga). Yoshinaga and his co-workers expanded the techniques by themselves. This paper describes the historical development of far-infrared spectroscopy before Fourier transform spectroscopy became popular around 1970.

  4. The Far-Infrared Surveyor (FIS) for AKARI

    NARCIS (Netherlands)

    Kawada, Mitsunobu; Baba, Hajime; Barthel, Peter D.; Clements, David; Cohen, Martin; Doi, Yasuo; Figueredo, Elysandra; Fujiwara, Mikio; Goto, Tomotsugu; Hasegawa, Sunao; Hibi, Yasunori; Hirao, Takanori; Hiromoto, Norihisa; Jeong, Woong-Seob; Kaneda, Hidehiro; Kawai, Toshihide; Kawamura, Akiko; Kester, Do; Kii, Tsuneo; Kobayashi, Hisato; Kwon, Suk Minn; Lee, Hyung Mok; Makiuti, Sin'itirou; Matsuo, Hiroshi; Matsuura, Shuji; Mueller, Thomas G.; Murakami, Noriko; Nagata, Hirohisa; Nakagawa, Takao; Narita, Masanao; Noda, Manabu; Oh, Sang Hoon; Okada, Yoko; Okuda, Haruyuki; Oliver, Sebastian; Ootsubo, Takafumi; Pak, Soojong; Park, Yong-Sun; Pearson, Chris P.; Rowan-Robinson, Michael; Saito, Toshinobu; Salama, Alberto; Sato, Shinji; Savage, Richard S.; Serjeant, Stephen; Shibai, Hiroshi; Shirahata, Mai; Sohn, Jungjoo; Suzuki, Toyoaki; Takagi, Toshinobu; Takahashi, Hidenori; Thomson, Matthew; Usui, Fumihiko; Verdugo, Eva; Watabe, Toyoki; White, Glenn J.; Wang, Lingyu; Yamamura, Issei; Yamauchi, Chisato; Yasuda, Akiko

    2007-01-01

    The Far-Infrared Surveyor (FIS) is one of two focal-plane instruments on the AKARI satellite. FIS has four photometric bands at 65, 90, 140, and 160 mu m, and uses two kinds of array detectors. The FIS arrays and optics are designed to sweep the sky with high spatial resolution and redundancy. The

  5. A study of Sn addition on bonding arrangement of Se-Te alloys using far infrared transmission spectroscopy

    International Nuclear Information System (INIS)

    Kumar, Rajneesh; Rangra, V. S.; Sharma, Parikshit; Katyal, S. C.; Sharma, Pankaj

    2011-01-01

    Far infrared transmission spectra of Se 92 Te 8-x Sn x (x = 0, 1, 2, 3, 4, 5) glassy alloys are obtained in the spectral range 50-600 cm -1 at room temperature. The results are interpreted in terms of the vibrations of the isolated molecular units in such a way so as to preserve fourfold and twofold coordination for Sn and chalcogen atoms (Se,Te), respectively. With the addition of Sn, Far-IR spectra shift toward high frequency side and some new bands start appearing. Sn atoms appear to substitute for the selenium atoms in the outrigger sites due to large bond formation probability. Theoretical calculations of bond energy, relative probability of bond formation, force constant, and wave number were also made to justify the result.

  6. Density functional theory for prediction of far-infrared vibrational frequencies: molecular crystals of astrophysical interest

    Science.gov (United States)

    Ennis, C.; Auchettl, R.; Appadoo, D. R. T.; Robertson, E. G.

    2017-11-01

    Solid-state density functional theory code has been implemented for the structure optimization of crystalline methanol, acetaldehyde and acetic acid and for the calculation of infrared frequencies. The results are compared to thin film spectra obtained from low-temperature experiments performed at the Australian Synchrotron. Harmonic frequency calculations of the internal modes calculated at the B3LYP-D3/m-6-311G(d) level shows higher deviation from infrared experiment than more advanced theory applied to the gas phase. Importantly for the solid-state, the simulation of low-frequency molecular lattice modes closely resembles the observed far-infrared features after application of a 0.92 scaling factor. This allowed experimental peaks to be assigned to specific translation and libration modes, including acetaldehyde and acetic acid lattice features for the first time. These frequency calculations have been performed without the need for supercomputing resources that are required for large molecular clusters using comparable levels of theory. This new theoretical approach will find use for the rapid characterization of intermolecular interactions and bonding in crystals, and the assignment of far-infrared spectra for crystalline samples such as pharmaceuticals and molecular ices. One interesting application may be for the detection of species of prebiotic interest on the surfaces of Kuiper-Belt and Trans-Neptunian Objects. At such locations, the three small organic molecules studied here could reside in their crystalline phase. The far-infrared spectra for their low-temperature solid phases are collected under planetary conditions, allowing us to compile and assign their most intense spectral features to assist future far-infrared surveys of icy Solar system surfaces.

  7. Science with High Spatial Resolution Far-Infrared Data

    Science.gov (United States)

    Terebey, Susan (Editor); Mazzarella, Joseph M. (Editor)

    1994-01-01

    The goal of this workshop was to discuss new science and techniques relevant to high spatial resolution processing of far-infrared data, with particular focus on high resolution processing of IRAS data. Users of the maximum correlation method, maximum entropy, and other resolution enhancement algorithms applicable to far-infrared data gathered at the Infrared Processing and Analysis Center (IPAC) for two days in June 1993 to compare techniques and discuss new results. During a special session on the third day, interested astronomers were introduced to IRAS HIRES processing, which is IPAC's implementation of the maximum correlation method to the IRAS data. Topics discussed during the workshop included: (1) image reconstruction; (2) random noise; (3) imagery; (4) interacting galaxies; (5) spiral galaxies; (6) galactic dust and elliptical galaxies; (7) star formation in Seyfert galaxies; (8) wavelet analysis; and (9) supernova remnants.

  8. A dual far-infrared laser diagnostic of magnetized plasmas

    International Nuclear Information System (INIS)

    Darrow, D.S.; Park, H.K.

    1988-02-01

    A dual far-infrared laser has been constructed and its properties have been exploited to probe tokamak-like discharges in the CDX toroidal device. Thermal variation of the difference frequency between the two far-infrared cavities is slow, though the cavities lack thermal stabilization, simply because their assembly on the same chassis exposes them to virtually identical temperature changes. The optical arrangement beyond the laser permits conversion within minutes between interferometry and density fluctuation observation, and within an hour between different operating wavelengths. Line-average densities of 2 /times/ 10 13 cm -3 and coherent fluctuations in the neighborhood of 20 kHz have been measured with this diagnostic. 15 refs., 5 figs., 2 tabs

  9. Cosmic far-infrared background at high galactic latitudes

    International Nuclear Information System (INIS)

    Stecker, F.W.; Puget, J.L.; Fazio, G.G.

    1977-01-01

    We predict far-infrared background fluxes from various cosmic sources. These fluxes lie near the high-frequency side of the blackbody radiation spectrum. These sources could account for a significant fraction of the background radiation at frequencies above 400 GHz which might be misinterpreted as a ''Comptonization'' distortion of the blackbody radiation. Particular attention is paid to the possible contributions from external galaxies, from rich clusters of galaxies, and from galactic dust emission

  10. Cosmic far-infrared background at high galactic latitudes

    International Nuclear Information System (INIS)

    Stecker, F.W.; Puget, J.L.; Fazio, G.G.

    1976-12-01

    Far-infrared background fluxes from various cosmic sources are predicted. These fluxes lie near the high-frequency side of the blackbody radiation spectrum. These sources could account for a significant fraction of the background radiation at frequencies above 400 GHz, which might be misinterpreted as a comptonization distortion of the blackbody radiation. Particular attention is paid to the possible contributions from external galaxies, rich clusters of galaxies and from galactic dust emission

  11. Far-infrared spectroscopy of thermally annealed tungsten silicide films

    International Nuclear Information System (INIS)

    Amiotti, M.; Borghesi, A.; Guizzetti, G.; Nava, F.; Santoro, G.

    1991-01-01

    The far-infrared transmittance spectrum of tungsten silicide has been observed for the first time. WSi 2 polycrystalline films were prepared by coevaporation and chemical-vapour deposition on silicon wafers, and subsequently thermally annealed at different temperatures. The observed structures are interpreted, on the basis of the symmetry properties of the crystal, such as infrared-active vibrational modes. Moreover, the marked lineshape dependence on annealing temperature enables this technique to analyse the formation of the solid silicide phases

  12. Far-infrared ferroelectric soft mode spectroscopy on thin films

    Czech Academy of Sciences Publication Activity Database

    Petzelt, Jan; Ostapchuk, Tetyana

    2001-01-01

    Roč. 249, 1-2 (2001), s. 81-88 ISSN 0015-0193 R&D Projects: GA ČR GA202/98/1282; GA AV ČR IAA1010918; GA MŠk OC 514.10 Institutional research plan: CEZ:AV0Z1010914 Keywords : far-infrared spectroscopy * soft mode * dielectric spectra * permitivity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.471, year: 2001

  13. Far infrared properties of PbTe doped with cerium

    International Nuclear Information System (INIS)

    Nikolic, P.M.; Koenig, W.; Vujatovic, S.S.; Blagojevic, V.; Lukovic, D.; Savic, S.; Radulovic, K.; Urosevic, D.; Nikolic, M.V.

    2007-01-01

    Single crystal samples of lead telluride doped with cerium were made using the Bridgman method. Far infrared reflectivity spectra in the temperature range from 10 to 300 K are presented. The experimental data were numerically analyzed using a fitting procedure based on the plasmon-phonon interaction model and optical parameters were determined. Two additional local modes were observed at about 138 and 337 cm -1 . The origin of these local vibrational impurity modes was discussed

  14. Far infrared properties of PbTe doped with cerium

    Energy Technology Data Exchange (ETDEWEB)

    Nikolic, P.M. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia)]. E-mail: nikolic@sanu.ac.yu; Koenig, W. [Max Planck Institut fuer Festkoerperforschung, Heisenbergstrasse 1, 7000 Stuttgart 80 (Germany); Vujatovic, S.S. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia); Blagojevic, V. [Faculty of Electronic Engineering, University of Belgrade, Bulevar Kralja Aleksandra 73, 11000 Belgrade (Serbia); Lukovic, D. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia); Savic, S. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia); Radulovic, K. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia); Urosevic, D. [Mathematical Institute SASA, Knez Mihailova 35/I, 11000 Belgrade (Serbia); Nikolic, M.V. [Center for Multidisciplinary Studies of the University of Belgrade, Kneza Viseslava 1, Belgrade (Serbia)

    2007-05-16

    Single crystal samples of lead telluride doped with cerium were made using the Bridgman method. Far infrared reflectivity spectra in the temperature range from 10 to 300 K are presented. The experimental data were numerically analyzed using a fitting procedure based on the plasmon-phonon interaction model and optical parameters were determined. Two additional local modes were observed at about 138 and 337 cm{sup -1}. The origin of these local vibrational impurity modes was discussed.

  15. An experimental study about effect of far infrared radiant ceramics on efficient methane fermentation

    International Nuclear Information System (INIS)

    Oda, A.; Yamazaki, M.; Oida, A.

    2003-01-01

    Methane fermentation, well known as one of the methods for organic wastes treatment, has been used as an energy production process in order to produce a gaseous fuel. But methane fermentation has some problems to be solved about gas production rate and volatile solids reduction efficiency. Simple methods to improve these problems are needed. In this study, we focused on far infrared radiant ceramics as a stimulating substance to activate methanogenic bacteria. Firstly, through the experiment of one batch fermentation, it was confirmed that the ceramics in the fermenter caused increase of total gas production. Next, even through the experiment of continuous fermentation, same stimulating effect was confirmed. It was considered that this effect was caused not only by a function of bio-contactor of the ceramics but also by far infrared radiation from ceramics. (author)

  16. ISO observations of far-infrared rotational emission lines of water vapor toward the supergiant star VY Canis Majoris

    OpenAIRE

    Neufeld, David A.; Feuchtgruber, Helmut; Harwit, Martin; Melnick, Gary J.

    1999-01-01

    We report the detection of numerous far-infrared emission lines of water vapor toward the supergiant star VY Canis Majoris. A 29.5 - 45 micron grating scan of VY CMa, obtained using the Short Wavelength Spectrometer (SWS) of the Infrared Space Observatory (ISO) at a spectral resolving power of approximately 2000, reveals at least 41 spectral features due to water vapor that together radiate a total luminosity ~ 25 solar luminosities. In addition to pure rotational transitions within the groun...

  17. The structural and optical constants of Ag2S semiconductor nanostructure in the Far-Infrared.

    Science.gov (United States)

    Zamiri, Reza; Abbastabar Ahangar, Hossein; Zakaria, Azmi; Zamiri, Golnoosh; Shabani, Mehdi; Singh, Budhendra; Ferreira, J M F

    2015-01-01

    In this paper a template-free precipitation method was used as an easy and low cost way to synthesize Ag2S semiconductor nanoparticles. The Kramers-Kronig method (K-K) and classical dispersion theory was applied to calculate the optical constants of the prepared samples, such as the reflective index n(ω) and dielectric constant ε(ω) in Far-infrared regime. Nanocrystalline Ag2S was synthesized by a wet chemical precipitation method. Ag2S nanoparticle was characterized by X-ray diffraction, Scanning Electron Microscopy, UV-visible, and FT-IR spectrometry. The refinement of the monoclinic β-Ag2S phase yielded a structure solution similar to the structure reported by Sadanaga and Sueno. The band gap of Ag2S nanoparticles is around 0.96 eV, which is in good agreement with previous reports for the band gap energy of Ag2S nanoparticles (0.9-1.1 eV). The crystallite size of the synthesized particles was obtained by Hall-Williamson plot for the synthesized Ag2S nanoparticles and it was found to be 217 nm. The Far-infrared optical constants of the prepared Ag2S semiconductor nanoparticles were evaluated by means of FTIR transmittance spectra data and K-K method. Graphical abstractThe Far-infrared optical constants of Ag2S semiconductor nanoparticles.

  18. High resolution far-infrared survey of A section of the galactic plane. I. The nature of the sources

    International Nuclear Information System (INIS)

    Jaffe, D.T.; Stier, M.T.; Fazio, G.G.

    1982-01-01

    We have surveyed a 7.5 deg 2 portion of the galactic plane between l/sup II/ = 10 0 and l/sup II/ = 16 0 at 70 μm with a 1' beam. We present far-infrared, radio continuum, and 12 CO and 13 CO line observations of the 42 far-infrared sources in the survey region. The sources range in luminosity from 4 x 10 3 to 3 x 10 6 L/sub sun/. Most are associated with 12 CO peaks. More than half of the sources have associated H 2 O maser emission. Half have associated radio continuum emission at a limit of 100 mJy. Eight sources have radio emission at weaker levels. In a number of cases, the far-infrared source is smaller than its associated radio source. This difference can be explained in the context of the ''blister'' picture of H II regions. One group of sources emits many fewer Lyman continuum photons than expected, given the far-infrared luminosities. We examine a number of possible reasons for this and conclude that the most reasonable explanation is that clusters of early type stars rather than single stars excite the far-infrared sources. We examine the energetics in the molecular clouds surrounding the infrared sources and conclude that the sources could supply the energy to explain the observed temperature structure and velocity field in the molecular gas

  19. Far-Infrared Absorption of PbSe Nanorods

    KAUST Repository

    Hyun, Byung-Ryool

    2011-07-13

    Measurements of the far-infrared absorption spectra of PbSe nanocrystals and nanorods are presented. As the aspect ratio of the nanorods increases, the Fröhlich sphere resonance splits into two peaks. We analyze this splitting with a classical electrostatic model, which is based on the dielectric function of bulk PbSe but without any free-carrier contribution. Good agreement between the measured and calculated spectra indicates that resonances in the local field factors underlie the measured spectra. © 2011 American Chemical Society.

  20. Generating Far-Infrared Radiation By Two-Wave Mixing

    Science.gov (United States)

    Borenstain, Shmuel

    1992-01-01

    Far-infrared radiation 1 to 6 GHz generated by two-wave mixing in asymmetrically grown GaAs/AlxGa1-xAs multiple-quantum-well devices. Two near-infrared semiconductor diode lasers phase-locked. Outputs amplified, then combined in semiconductor nonlinear multiple-quantum-well planar waveguide. Necessary to optimize design of device with respect to three factors: high degree of confinement of electromagnetic field in nonlinear medium to maximize power density, phase matching to extend length of zone of interaction between laser beams in non-linear medium, and nonlinear susceptibility. Devices used as tunable local oscillators in heterodyne-detection radiometers.

  1. Optical Properties of Natural Minerals in the Far-Infrared

    Science.gov (United States)

    Long, Larry Lavern

    The reflectivity of natural mineral powders were measured in the far infrared. The complex indices of refraction were then determined by Kramers-Kronig analysis or dispersive analysis. The samples were constructed by pressing the powdered sample into a 13 mm diameter pellet. A few of the samples that were measured were kaolin, illite, and montmorillonite, clay samples that could not be obtained in large single crystals. For calcite and gypsum crystals a comparison between the single crystal measurements and powder measurements was done to determine the effect of sample preparation on the measured spectra.

  2. Bolometers for far-infrared and submillimetre astronomy

    International Nuclear Information System (INIS)

    Griffin, M.J.

    2000-01-01

    Important scientific goals of far-infrared and submillimetre astronomy include measurements of anisotropies in the cosmic background radiation, deep imaging surveys for detection of high-red-shift galaxies, and imaging and spectroscopy of star formation regions and the interstellar medium in the milky way and nearby galaxies. Use of sensitive bolometer arrays leads to very large improvements in observing speed. Recent progress in the development of bolometric detector systems for ground-based and space-borne far-infrared and submillimetre astronomical observations is reviewed, including spider-web NTD bolometers, transition-edge superconducting sensors, and micromachined planar arrays of ion-implanted silicon bolometers. Future arrays may be based on planar absorbers without feedhorns, which offer potential advantages including more efficient use of space in the focal plane and improved instantaneous sampling of the telescope point spread function, but present challenges in suppression of stray light and RF interference. FIRST and Planck Surveyor are planned satellite missions involving passively cooled (∼70 K) telescopes, and bolometer array developments for these missions are described

  3. Far-infrared Spectroscopic Characterization of Anti-vinyl Alcohol

    Science.gov (United States)

    Bunn, Hayley; Soliday, Rebekah M.; Sumner, Isaiah; Raston, Paul L.

    2017-09-01

    We report a detailed analysis of the high-resolution far-infrared spectrum of anti-vinyl alcohol, which has been previously identified toward Sagittarius B2(N). The ν 15 OH torsional fundamental investigated here is more than 200 cm-1 removed from the next nearest vibration, making it practically unperturbed and ideal to help refine the ground state rotational constants that were previously determined from 25 microwave lines. We assigned 1335 lines within the ν 15 fundamental centered at 261.5512 cm-1, with J and K a ranges of 1-59 and 0-16, respectively. The microwave and far-infrared line positions were fit with Watson-type A- and S-reduced Hamiltonians, with the inclusion of quartic and select sextic distortion terms. This resulted in a significant refinement of the ground state constants, in addition to the determination of the {ν }15=1 state constants for the first time. The spectroscopic parameters are in good agreement with the results from anharmonic coupled-cluster calculations, and should be useful in searches for rotationally and/or vibrationally warm anti-vinyl alcohol in interstellar molecular clouds.

  4. Active Control of Nitride Plasmonic Dispersion in the Far Infrared.

    Energy Technology Data Exchange (ETDEWEB)

    Shaner, Eric A.; Dyer, Gregory Conrad; Seng, William Francis; Bethke, Donald Thomas; Grine, Albert Dario,; Baca, Albert G.; Allerman, Andrew A.

    2014-11-01

    We investigate plasmonic structures in nitride-based materials for far-infrared (IR) applications. The two dimensional electron gas (2DEG) in the GaN/AlGaN material system, much like metal- dielectric structures, is a patternable plasmonic medium. However, it also permits for direct tunability via an applied voltage. While there have been proof-of-principle demonstrations of plasma excitations in nitride 2DEGs, exploration of the potential of this material system has thus far been limited. We recently demonstrated coherent phenomena such as the formation of plasmonic crystals, strong coupling of tunable crystal defects to a plasmonic crystal, and electromagnetically induced transparency in GaAs/AlGaAs 2DEGs at sub-THz frequencies. In this project, we explore whether these effects can be realized in nitride 2DEG materials above 1 THz and at temperatures exceeding 77 K.

  5. Vacuum variable-angle far-infrared ellipsometer

    Science.gov (United States)

    Friš, Pavel; Dubroka, Adam

    2017-11-01

    We present the design and performance of a vacuum far-infrared (∼50-680 cm-1) ellipsometer with a rotating analyser. The system is based on a Fourier transform spectrometer, an in-house built ellipsometer chamber and a closed-cycle bolometer. The ellipsometer chamber is equipped with a computer controlled θ-2θ goniometer for automated measurements at various angles of incidence. We compare our measurements on SrTiO3 crystal with the results acquired above 300 cm-1 with a commercially available ellipsometer system. After the calibration of the angle of incidence and after taking into account the finite reflectivity of mirrors in the detector part we obtain a very good agreement between the data from the two instruments. The system can be supplemented with a closed-cycle He cryostat for measurements between 5 and 400 K.

  6. Far infrared study of molecular reorientations in some alkoxyazoxybenzenes

    International Nuclear Information System (INIS)

    Godlewska, M.; Kocot, A.

    1986-05-01

    Far infrared spectra in the frequency range 20 - 200 cm -1 for di-n-alkoxyazoxybenzene homologous series are presented for the isotropic and nematic phases and for 0.1 M solution in benzene. Additionally some partly deuterated samples were measured. The spectra generally consist of two broad bands. By comparison of the spectra for differently deuterated compounds it was possible to interpret the higher frequency band as being connected with the intermolecular torsional vibration of the groups. We connect the band at lower frequencies with the Poley absorption of librating molecules. The confined rotator model calculations performed for this band for all compounds studied give the rotational correlation time which happens to be in good agreement with the correlation times as derived from the quasielastic neutron scattering experiments. 12 refs., 7 figs., 3 tabs. (author)

  7. The Far-Infrared Properties of the Most Isolated Galaxies

    Science.gov (United States)

    Lisenfeld, U.; Verdes-Montenegro, L.; Sulentic, J.; Leon, S.; Espada, D.; Bergond, G.; García, E.; Sabater, J.; Santander-Vela, J. D.; Verley, S.

    2007-05-01

    A long-standing question in galaxy evolution involves the role of nature (self-regulation) vs. nurture (environment) on the observed properties (and evolution) of galaxies. A collaboration centreed at the Instituto de Astrofisica de Andalucia (Granada, Spain) is trying to address this question by producing a observational database for a sample of 1050 isolated galaxies from the catalogue of Karachentseva (1973) with the overarching goal being the generation of a "zero-point" sample against which effects of environment on galaxies can be assessed. The AMIGA (Analysis of the Interstellar Medium of Isolated Galaxies) database (see www.iaa.es/AMIGA.html) will include optical, IR and radio line and continuum measures. The galaxies in the sample represent the most isolated galaxies in the local universe. In the present contribution, we will present the project, as well as the results of an analysis of the far-infrared (FIR) and molecular gas properties of this sample.

  8. Far infrared radiation (FIR): its biological effects and medical applications.

    Science.gov (United States)

    Vatansever, Fatma; Hamblin, Michael R

    2012-11-01

    Far infrared (FIR) radiation (λ = 3-100 μm) is a subdivision of the electromagnetic spectrum that has been investigated for biological effects. The goal of this review is to cover the use of a further sub-division (3- 12 μm) of this waveband, that has been observed in both in vitro and in vivo studies, to stimulate cells and tissue, and is considered a promising treatment modality for certain medical conditions. Technological advances have provided new techniques for delivering FIR radiation to the human body. Specialty lamps and saunas, delivering pure FIR radiation (eliminating completely the near and mid infrared bands), have became safe, effective, and widely used sources to generate therapeutic effects. Fibers impregnated with FIR emitting ceramic nanoparticles and woven into fabrics, are being used as garments and wraps to generate FIR radiation, and attain health benefits from its effects.

  9. Estimate of Radiosonde Dry Bias From Far-Infrared Measurements on the Antarctic Plateau

    Science.gov (United States)

    Rizzi, R.; Maestri, T.; Arosio, C.

    2018-03-01

    The experimental data set of downwelling radiance spectra measured at the ground in clear conditions during 2013 by a Far-Infrared Fourier Transform Spectrometer at Dome-C, Antarctica, presented in Rizzi et al. (2016, https://doi.org/10.1002/2016JD025341) is used to estimate the effect of solar heating of the radiosonde humidity sensor, called dry bias. The effect is quite evident comparing residuals for the austral summer and winter clear cases and can be modeled by an increase of the water vapor concentration at all levels by about 15%. Such an estimate has become possible only after a new version of the simulation code and spectroscopic data has become available, which has substantially improved the modeling of water vapor absorption in the far infrared. The negative yearly spectral bias reported in Rizzi et al. (2016, https://doi.org/10.1002/2016JD025341) is in fact greatly reduced when compared to the same measurement data set.

  10. Far-infrared Fourier Transform Spectroscopy Measurements of Mn12-acetate.

    Science.gov (United States)

    Tu, Jiufeng; Suzuki, Yoko; Mertes, K. M.; Sarachik, M. P.; Agladze, N. I.; Sievers, A. J.; Rumberger, E. M.; Hendrickson, D. N.; Christou, G.

    2004-03-01

    The transmission spectra of both powder samples and assemblies of single crystals of Mn_12-acetate were measured in the far infrared region (2.0 - 20 cm-1) using a Fourier transform technique. The energies of the observed aborption lines agree with those obtained by Mukhin et al. [1] using the backwards wave oscillator technique. The temperature dependence of the aborption lines, as well as the presence of additional absorption lines, will be discussed. [1] A. A. Mukhin, V. D. Travkin, A. K. Zvesdin, A. Caneschi, D. Gatteschi and R. Sessoli, Physica B 284-288 (2000) 1221-1222

  11. Single mode operation of a hybrid optically pumped D2O far infrared laser

    International Nuclear Information System (INIS)

    Yuan, D.C.; Siegrist, M.R.

    1990-04-01

    We have achieved single mode operation in a hybrid optically pumped D 2 O far infrared laser. The active volume of the resonator was divided into two sections separated by a thin plastic foil. The larger section served as the main gain medium and the shorter section as mode selective element. The vapor pressure in the smaller volume was either very low or alternatively about 3 times higher than the pressure in the main part. In both cases single mode operation was achieved without any reduction of the total output energy. (author) 13 refs., 7 figs

  12. Origins Space Telescope: The Far Infrared Imager and Polarimeter FIP

    Science.gov (United States)

    Staguhn, Johannes G.; Chuss, David; Howard, Joseph; Meixner, Margaret; Vieira, Joaquin; Amatucci, Edward; Bradley, Damon; Carter, Ruth; Cooray, Asantha; Flores, Anel; Leisawitz, David; Moseley, Samuel Harvey; Wollack, Edward; Origins Space Telescope Study Team

    2018-01-01

    The Origins Space Telescope (OST)* is the mission concept for the Far-Infrared Surveyor, one of the four science and technology definition studies of NASA Headquarters for the 2020 Astronomy and Astrophysics Decadal survey. The current "concept 1", which envisions a cold (4K) 9m space telescope, includes 5 instruments, providing a wavelength coverage ranging from 6um and 667um. The achievable sensitivity of the observatory will provide three to four orders of magnitude of improvement in sensitivity over current observational capabilities, allowing to address a wide range of new and so far inaccessible scientific questions, ranging from bio-signatures on exo-planets to mapping primordial H_2 from the "dark ages" before the universe went through the phase of re-ionization.Here we present the Far Infrared Imager and Polarimeter (FIP) for OST. The cameral will cover four bands, 40um, 80um, 120um, and 240um. It will allow for differential polarimetry in those bands with the ability to observe two colors in polarimtery mode simultaneously, while all four bands can be observed simultaneously in total power mode. While the confusion limit will be reached in only 32ms at 240um, at 40um the source density on the sky is so low, that at the angular resolution of 1" of OST at this wavelength there will be no source confusion, even for the longest integration times. Science topics that can be addressed by FIP include but are not limited to galactic and extragalactic magnetic field studies, Deep Galaxy Surveys, and Outer Solar System objects..*Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. We welcome you to contact the Science and Technology Definition Team (STDT) with your science needs and ideas by emailing us at ost_info@lists.ipac.caltech.edu

  13. Enhancement of isobutane refrigerator performance by using far-infrared coating

    International Nuclear Information System (INIS)

    Hsu, Yu-Chun; Teng, Tun-Ping

    2016-01-01

    Highlights: • Two-step synthesis method was employed to produce FIRCs. • Emissivity of FIRCs was determined using a FT-IR. • The highest emissivity of FIRMs was MWCNT. • No-load pull-down and 24-h on-load cycling test were performed. • The COP and EF of S2 were greater than those of S1 by 5.92% and 7.89%. - Abstract: This study evaluated the effect on refrigeration performance and feasibility of a far-infrared coating (FIRC) on the condenser of a small isobutane (R-600a) refrigerator. The evaluation was based on the no-load pull-down and 24-h on-load cycling tests. Far-infrared materials and a water-based coating material were mixed using a two-step synthesis method to obtain the FIRC material. Fourier transform infrared spectrometry established that the optimal far-infrared material was a multiwalled carbon nanotube (MWCNT). The results of the no-load pull-down test revealed that the electricity consumption, freezer temperature, and coefficient of performance (COP) of the R-600a refrigerator with MWCNT-FIRC (S2) were lower than those of the refrigerator without MWCNT-FIRC (S1) by 3.39%, 3.61%, and 2.92%, respectively. The results of the 24-h on-load cycling test showed that S2 had a lower electricity consumption, higher slope of pull-down (SPD), higher compression ratio (CR), higher COP, lower duty ratio (DR), and higher energy factor (EF), changing upon those of S1 by −7.05%, 5.66%, 3.24%, 5.92%, −5.63, and 7.89%, respectively. A MWCNT-FIRC on the condenser of an R-600a refrigerator can enhance refrigeration performance and reduce electricity consumption, resulting in energy saving and carbon reduction.

  14. ESPRIT: a study concept for a far-infrared interferometer in space

    Science.gov (United States)

    Wild, W.; de Graauw, Th.; Helmich, F.; Baryshev, A.; Cernicharo, J.; Gao, J. R.; Gunst, A.; Bos, A.; den Herder, J.-W.; Jackson, B.; Koshelets, V.; Langevelde, H.-J.; Maat, P.; Martin-Pintado, J.; Noordam, J.; Roelfsema, P.; Venema, L.; Wesselius, P.; Yagoubov, P.

    2008-07-01

    In the far-infrared (FIR) / THz regime the angular (and often spectral) resolution of observing facilities is still very restricted despite the fact that this frequency range has become of prime importance for modern astrophysics. ALMA (Atacama Large Millimeter Array) with its superb sensitivity and angular resolution will only cover frequencies up to about 1 THz, while the HIFI instrument for ESA'a Herschel Space Observatory will provide limited angular resolution (10 to 30 arcsec) up to 2 THz. Observations of regions with star and planet formation require extremely high angular resolution as well as frequency resolution in the full THz regime. In order to open these regions for high-resolution astrophysics we present a study concept for a heterodyne space interferometer, ESPRIT (Exploratory Submm Space Radio-Interferometric Telescope). This mission will cover the Terahertz regime inaccessible from the ground and outside the operating range of the James Webb Space Telescope (JWST).

  15. Cleanability evaluation of ceramic glazes with nanometer far-infrared materials using contact angle measurement.

    Science.gov (United States)

    Wang, Lijuan; Liang, Jinsheng; Di, Xingfu; Tang, Qingguo

    2014-05-01

    The cleanability of easy-to-clean ceramic glazes doped with nanometer far-infrared materials was compared with that of some high-quality household ceramic glazes from the market. The cleanability was evaluated by the contact angle measurement using a sessile drop method with a Dataphysics OCA-30 contact angle analyzer. The results showed that the difference of contact angles of water on the glazes before soiling and after cleaning could be used as a parameter for evaluating the cleanability of the glazes. The relationship between cleanability and surface properties, such as surface free energy and surface topography, was investigated. The surface free energy of the samples and their components were calculated using van Oss acid-base approach. By measuring advancing and receding contact angles, the contact angle hysteresis of the ceramic glazes due to the surface topography was investigated. It was shown that the cleanability of ceramic glazes containing nanometer far-infrared materials (NFIM) is better than that of household ceramic glazes from market, due to a higher ratio of electron-acceptor parameter to electron-donor parameter, which led to the effect of water hydration as well as better hydrophilic property and increased smoothness. The contact angle measurement not only accurately evaluates the cleanability of the ceramic glazes, but also has a contribution to the study of cleanability theory. Moreover, this method is simple, convenient and less sample-consumption.

  16. Local Volume Hi Survey: the far-infrared radio correlation

    Science.gov (United States)

    Shao, Li; Koribalski, Bärbel S.; Wang, Jing; Ho, Luis C.; Staveley-Smith, Lister

    2018-06-01

    In this paper we measure the far-infrared (FIR) and radio flux densities of a sample of 82 local gas-rich galaxies, including 70 "dwarf" galaxies (M* correlation (FRC) over four orders of magnitude (F_1.4GHz ∝ F_FIR^{1.00± 0.08}). However, for detected galaxies only, a trend of larger FIR-to-radio ratio with decreasing flux density is observed. We estimate the star formation rate by combining UV and mid-IR data using empirical calibration. It is confirmed that both FIR and radio emission are strongly connected with star formation but with significant non-linearity. Dwarf galaxies are found radiation deficient in both bands, when normalized by star formation rate. It urges a "conspiracy" to keep the FIR-to-radio ratio generally constant. By using partial correlation coefficient in Pearson definition, we identify the key galaxy properties associated with the FIR and radio deficiency. Some major factors, such as stellar mass surface density, will cancel out when taking the ratio between FIR and radio fluxes. The remaining factors, such as HI-to-stellar mass ratio and galaxy size, are expected to cancel each other due to the distribution of galaxies in the parameter space. Such cancellation is probably responsible for the "conspiracy" to keep the FRC alive.

  17. Polarization of far-infrared radiation from molecular clouds

    Science.gov (United States)

    Novak, G.; Gonatas, D. P.; Hildebrand, R. H.; Platt, S. R.; Dragovan, M.

    1989-01-01

    The paper reports measurements of the polarization of far-infrared emission from dust in nine molecular clouds. Detections were obtained in Mon R2, in the Kleinmann-Low (KL) nebula in Orion, and in Sgr A. Upper limits were set for six other clouds. A comparison of the 100 micron polarization of KL with that previously measured at 270 microns provides new evidence that the polarization is due to emission from magnetically aligned dust grains. Comparing the results for Orion with measurements at optical wavelengths, it is inferred that the magnetic field direction in the outer parts of the Orion cloud is the same as that in the dense core. This direction is nearly perpendicular to the ridge of molecular emission and is parallel to both the molecular outflow in KL and the axis of rotation of the cloud core. In Mon R2, the field direction which the measurements imply does not agree withthat derived from 0.9-2.2 micron polarimetry. The discrepancy is attributed to scattering in the near-infrared. In Orion and Sgr A, where comparisons are possible, the measurements are in good agreement with 10 micron polarization measurements.

  18. HerMES: THE FAR-INFRARED EMISSION FROM DUST-OBSCURED GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Calanog, J. A.; Wardlow, J.; Fu, Hai; Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Assef, R. J. [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Bock, J.; Riechers, D.; Schulz, B. [California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Casey, C. M. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Farrah, D.; Oliver, S. J.; Roseboom, I. G. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Ibar, E. [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22 (Chile); Kartaltepe, J. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Magdis, G.; Rigopoulou, D. [Department of Astrophysics, Denys Wilkinson Building, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Marchetti, L. [Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA (United Kingdom); Pérez-Fournon, I. [Instituto de Astrofísica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Scott, Douglas [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); and others

    2013-09-20

    Dust-obscured galaxies (DOGs) are an ultraviolet-faint, infrared-bright galaxy population that reside at z ∼ 2 and are believed to be in a phase of dusty star-forming and active galactic nucleus (AGN) activity. We present far-infrared (far-IR) observations of a complete sample of DOGs in the 2 deg{sup 2} of the Cosmic Evolution Survey. The 3077 DOGs have (z) = 1.9 ± 0.3 and are selected from 24 μm and r {sup +} observations using a color cut of r {sup +} – [24] ≥ 7.5 (AB mag) and S{sub 24} ≥ 100 μJy. Based on the near-IR spectral energy distributions, 47% are bump DOGs (star formation dominated) and 10% are power-law DOGs (AGN-dominated). We use SPIRE far-IR photometry from the Herschel Multi-tiered Extragalactic Survey to calculate the IR luminosity and characteristic dust temperature for the 1572 (51%) DOGs that are detected at 250 μm (≥3σ). For the remaining 1505 (49%) that are undetected, we perform a median stacking analysis to probe fainter luminosities. Herschel-detected and undetected DOGs have average luminosities of (2.8 ± 0.4) × 10{sup 12} L{sub ☉} and (0.77 ± 0.08) × 10{sup 12} L{sub ☉}, and dust temperatures of (33 ± 7) K and (37 ± 5) K, respectively. The IR luminosity function for DOGs with S{sub 24} ≥ 100 μJy is calculated, using far-IR observations and stacking. DOGs contribute 10%-30% to the total star formation rate (SFR) density of the universe at z = 1.5-2.5, dominated by 250 μm detected and bump DOGs. For comparison, DOGs contribute 30% to the SFR density for all z = 1.5-2.5 galaxies with S{sub 24} ≥ 100 μJy. DOGs have a large scatter about the star formation main sequence and their specific SFRs show that the observed phase of star formation could be responsible for their total observed stellar mass at z ∼ 2.

  19. HerMES: THE FAR-INFRARED EMISSION FROM DUST-OBSCURED GALAXIES

    International Nuclear Information System (INIS)

    Calanog, J. A.; Wardlow, J.; Fu, Hai; Cooray, A.; Assef, R. J.; Bock, J.; Riechers, D.; Schulz, B.; Casey, C. M.; Conley, A.; Farrah, D.; Oliver, S. J.; Roseboom, I. G.; Ibar, E.; Kartaltepe, J.; Magdis, G.; Rigopoulou, D.; Marchetti, L.; Pérez-Fournon, I.; Scott, Douglas

    2013-01-01

    Dust-obscured galaxies (DOGs) are an ultraviolet-faint, infrared-bright galaxy population that reside at z ∼ 2 and are believed to be in a phase of dusty star-forming and active galactic nucleus (AGN) activity. We present far-infrared (far-IR) observations of a complete sample of DOGs in the 2 deg 2 of the Cosmic Evolution Survey. The 3077 DOGs have (z) = 1.9 ± 0.3 and are selected from 24 μm and r + observations using a color cut of r + – [24] ≥ 7.5 (AB mag) and S 24 ≥ 100 μJy. Based on the near-IR spectral energy distributions, 47% are bump DOGs (star formation dominated) and 10% are power-law DOGs (AGN-dominated). We use SPIRE far-IR photometry from the Herschel Multi-tiered Extragalactic Survey to calculate the IR luminosity and characteristic dust temperature for the 1572 (51%) DOGs that are detected at 250 μm (≥3σ). For the remaining 1505 (49%) that are undetected, we perform a median stacking analysis to probe fainter luminosities. Herschel-detected and undetected DOGs have average luminosities of (2.8 ± 0.4) × 10 12 L ☉ and (0.77 ± 0.08) × 10 12 L ☉ , and dust temperatures of (33 ± 7) K and (37 ± 5) K, respectively. The IR luminosity function for DOGs with S 24 ≥ 100 μJy is calculated, using far-IR observations and stacking. DOGs contribute 10%-30% to the total star formation rate (SFR) density of the universe at z = 1.5-2.5, dominated by 250 μm detected and bump DOGs. For comparison, DOGs contribute 30% to the SFR density for all z = 1.5-2.5 galaxies with S 24 ≥ 100 μJy. DOGs have a large scatter about the star formation main sequence and their specific SFRs show that the observed phase of star formation could be responsible for their total observed stellar mass at z ∼ 2

  20. Determination of thicknesses and temperatures of crystalline silicon wafers from optical measurements in the far infrared region

    Science.gov (United States)

    Franta, Daniel; Franta, Pavel; Vohánka, Jiří; Čermák, Martin; Ohlídal, Ivan

    2018-05-01

    Optical measurements of transmittance in the far infrared region performed on crystalline silicon wafers exhibit partially coherent interference effects appropriate for the determination of thicknesses of the wafers. The knowledge of accurate spectral and temperature dependencies of the optical constants of crystalline silicon in this spectral region is crucial for the determination of its thickness and vice versa. The recently published temperature dependent dispersion model of crystalline silicon is suitable for this purpose. Because the linear thermal expansion of crystalline silicon is known, the temperatures of the wafers can be determined with high precision from the evolution of the interference patterns at elevated temperatures.

  1. Far-infrared observations of Large Magellanic Cloud H II regions

    International Nuclear Information System (INIS)

    Werner, M.W.; Becklin, E.E.; Gatley, I.; Ellis, M.J.; Hyland, A.R.; Robinson, G.; Thomas, J.A.

    1978-01-01

    Far-infrared emission has been measured from four Large Magellanic Cloud H II regions: the 30 Doradus nebula, MC75, MC76 and MC77. The far-infrared radiation is thermal emission from dust heated by starlight. The results show that the LMC H II regions, like H II regions in the Galaxy, have far-infrared luminosities comparable to the total luminosity of their exciting stars. (author)

  2. Prediction of the diffuse far-infrared flux from the galactic plane

    International Nuclear Information System (INIS)

    Fazio, G.G.; Stecker, F.W.

    1976-01-01

    A basic model and simple numerical relations useful for future far-infrared studies of the Galaxy are presented. Making use of recent CO and other galactic surveys, we then predict the diffuse far-infrared flux distribution from the galactic plane as a function of galactic longitude l for 4degree< or =l< or =90degree and the far-infrared emissivity as a function of galactocentric distance. Future measurements of the galactic far-infrared flux would yield valuable information on the physical properties and distribution of dust and molecular clouds in the Galaxy, particulary the inner region

  3. Far-infrared to Millimeter Data of Protoplanetary Disks: Dust Growth in the Taurus, Ophiuchus, and Chamaeleon I Star-forming Regions

    Energy Technology Data Exchange (ETDEWEB)

    Ribas, Álvaro; Espaillat, Catherine C.; Macías, Enrique [Department of Astronomy, Boston University, Boston, MA 02215 (United States); Bouy, Hervé [Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, F-33615 Pessac (France); Andrews, Sean; Wilner, David [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 91023 (United States); Calvet, Nuria [Astronomy Department, University of Michigan, Ann Arbor, MI 48109 (United States); Naylor, David A.; Van der Wiel, Matthijs H. D. [Institute for Space Imaging Science, Department of Physics and Astronomy, University of Lethbridge (Canada); Riviere-Marichalar, Pablo, E-mail: aribas@bu.edu [Instituto de Ciencia de Materiales de Madrid (CSIC). Calle Sor Juana Inés de la Cruz 3, E-28049 Cantoblanco, Madrid (Spain)

    2017-11-01

    Far-infrared and (sub)millimeter fluxes can be used to study dust in protoplanetary disks, the building blocks of planets. Here, we combine observations from the Herschel Space Observatory with ancillary data of 284 protoplanetary disks in the Taurus, Chamaeleon I, and Ophiuchus star-forming regions, covering from the optical to mm/cm wavelengths. We analyze their spectral indices as a function of wavelength and determine their (sub)millimeter slopes when possible. Most disks display observational evidence of grain growth, in agreement with previous studies. No correlation is found between other tracers of disk evolution and the millimeter spectral indices. A simple disk model is used to fit these sources, and we derive posterior distributions for the optical depth at 1.3 mm and 10 au, the disk temperature at this same radius, and the dust opacity spectral index β . We find the fluxes at 70 μ m to correlate strongly with disk temperatures at 10 au, as derived from these simple models. We find tentative evidence for spectral indices in Chamaeleon I being steeper than those of disks in Taurus/Ophiuchus, although more millimeter observations are needed to confirm this trend and identify its possible origin. Additionally, we determine the median spectral energy distribution of each region and find them to be similar across the entire wavelength range studied, possibly due to the large scatter in disk properties and morphologies.

  4. Design of a far infrared interferometer diagnostic support structure

    International Nuclear Information System (INIS)

    Brooksby, C.A.; Rice, B.W.; Peebles, W.A.

    1987-10-01

    The Far Infrared Interferometer (FIR) diagnostic will operate in the 119 to 400 micron range to measure the plasma electron density on the Microwave Tokamak Experiment (MTX) being set up at LLNL. This diagnostic is a multi-channel system which incorporates a long elliptically shaped beam that passes through the plasma and is imaged onto an array of 14 detectors that are located on a table above the machine. The reference beam is brought around the machine and mixed with the plasma beam onto the detectors. The density is measured by a phase shift between these beams and is, therefore, very sensitive to path length changes between the two beam paths due to motion of the support structure. The design goal for allowable phase shifts caused by changes in the path length due to structure movement is 1/50th of a wavelength (2.4 to 8 microns). The structure needs to maintain this stability during the 0.5 second plasma shot. The structure is approximately 5 meters tall to support the optics table above the machine. In order to reduce the structure motion to the required level the forces acting on it were evaluated. The forces evaluated were eddy currents from the pulsed electromagnetic fields, the ambient ground motion, and the floor movement as the magnets are pulsed. The designs for similar diagnostic interferometers on other tokamaks were also reviewed to evaluate the forces and motions that might cause such small deflections in the support structure. Our structure is somewhat unique in that it is designed for operation in relatively large pulsed magnetic fields (100 to 7000 gauss) arising from the air core transformer of MTX. The design chosen incorporates a very rigid structure with high resistive and non-conductive materials. The choice of materials selected is discussed with reference to their response to expected forces. 14 refs., 10 figs

  5. Far-infrared and submillimeter spectroscopy of photodissociation regions

    International Nuclear Information System (INIS)

    Qaiyum, A.

    1993-12-01

    The physical properties of the galactic and extragalactic photodissociation regions, warm gas components molecular clouds are, generally, derived through the far-infrared (FIR) fine structure and submillimeter line emissions arising out of these regions. In the theoretical studies of these lines the model of Tielens and Hollenbach (herein after referred as TH) are usually employed in which all the opacity is assumed local in escape probability formalism and inward directed photons do not escape. These assumptions are contrary to the observational facts, where most of the lines are found optically thin except OI (63 μm) and low rotational transitions of CO and some other molecules. The optically thin medium will allow the radiation to escape through any face of the region. These observational evidences let us to assume finite parallel plane slab, instead of semi-infinite parallel slab, in which the photons are allowed to escape from both surfaces (back and front). In the present study an attempt has been made to incorporate the two sided escape of photons from the PDRs and to study its effect on the FIR and submillimeter line emission from the PDRs/molecular clouds. Further the present formalism is also employed to study the clumpy PDRs/molecular clouds. The preliminary results show that now serious consequences are found on the thermal and chemical structure of the regions but individual line emissions are modified by differing factors. Particularly at low density and low kinetic temperature the change is substantial but at density greater than the critical density of the line and temperature close to the excitation temperature its effect is almost negligible. An attempt has also been made to study the physical conditions of the M17 region employing the present formalism. (author). 49 refs, 8 figs, 1 tab

  6. Infrared-faint radio sources remain undetected at far-infrared wavelengths. Deep photometric observations using the Herschel Space Observatory

    Science.gov (United States)

    Herzog, A.; Norris, R. P.; Middelberg, E.; Spitler, L. R.; Leipski, C.; Parker, Q. A.

    2015-08-01

    Context. Showing 1.4 GHz flux densities in the range of a few to a few tens of mJy, infrared-faint radio sources (IFRS) are a type of galaxy characterised by faint or absent near-infrared counterparts and consequently extreme radio-to-infrared flux density ratios up to several thousand. Recent studies showed that IFRS are radio-loud active galactic nuclei (AGNs) at redshifts ≳2, potentially linked to high-redshift radio galaxies (HzRGs). Aims: This work explores the far-infrared emission of IFRS, providing crucial information on the star forming and AGN activity of IFRS. Furthermore, the data enable examining the putative relationship between IFRS and HzRGs and testing whether IFRS are more distant or fainter siblings of these massive galaxies. Methods: A sample of six IFRS was observed with the Herschel Space Observatory between 100 μm and 500 μm. Using these results, we constrained the nature of IFRS by modelling their broad-band spectral energy distribution (SED). Furthermore, we set an upper limit on their infrared SED and decomposed their emission into contributions from an AGN and from star forming activity. Results: All six observed IFRS were undetected in all five Herschel far-infrared channels (stacking limits: σ = 0.74 mJy at 100 μm, σ = 3.45 mJy at 500 μm). Based on our SED modelling, we ruled out the following objects to explain the photometric characteristics of IFRS: (a) known radio-loud quasars and compact steep-spectrum sources at any redshift; (b) starburst galaxies with and without an AGN and Seyfert galaxies at any redshift, even if the templates were modified; and (c) known HzRGs at z ≲ 10.5. We find that the IFRS analysed in this work can only be explained by objects that fulfil the selection criteria of HzRGs. More precisely, IFRS could be (a) known HzRGs at very high redshifts (z ≳ 10.5); (b) low-luminosity siblings of HzRGs with additional dust obscuration at lower redshifts; (c) scaled or unscaled versions of Cygnus A at any

  7. Far-infrared investigation of the Taurus star-forming region using the IRAS database

    International Nuclear Information System (INIS)

    Hughes, J.D.

    1986-01-01

    The Taurus-Auriga complex was selected as the first molecular cloud to be investigated in this study. The Taurus clouds were defined as lying between 04h and 05h in R.A. and +16 to +31 degrees in Dec., then the IRAS point-source catalogue was searched for sources with good or moderate quality fluxes in all three of the shortest IRAS bands. The sources selected were then classified into subgroups according to their IRAS colors. Taurus is generally believed to be an area of low-mass star formation, having no luminous O-B associations within or near to the cloud complex. Once field stars, galaxies and planetary nebulae had been removed from the sample only the molecular cloud cores, T Tauri stars and a few emission-line A and B stars remained. The great majority of these objects are pre-main sequence in nature and, as stated by Chester (1985), main sequence stars without excess far-infrared emission would only be seen in Taurus if their spectral types were earlier than about A5 and then not 25 microns. By choosing our sample in this way we are naturally selecting the hotter and thus more evolved sources. To counteract this, the molecular cloud core-criterion was applied to soruces with good or moderate quality flux at 25, 60 and 100 microns, increasing the core sample by about one third. The candidate protostar B335 is only detected by IRAS at 60 and 100 microns while Taurus is heavily contaminated by cirrus at 100 microns. This means that detection at 25 microns is also required with those at 60 and 100 microns to avoid confusing a ridge of cirrus with a genuine protostar. The far-infrared luminosity function of these sources is then calculated and converted to the visual band by a standard method to compare with the field star luminosity function of Miller and Scalo

  8. Downwelling Far-Infrared Radiance Spectra Measured by FIRST at Cerro Toco, Chile

    Science.gov (United States)

    Mast, J. C.; Mlynczak, M. G.; Cageao, R.; Kratz, D. P.; Latvakoski, H.; Johnson, D. G.; Mlawer, E. J.; Turner, D. D.

    2015-12-01

    The Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument is a Fourier transform spectrometer developed by NASA Langley Research Center in collaboration with the Space Dynamics Laboratory and the Harvard-Smithsonian Center for Astrophysics. FIRST was initially developed for measuring the far-infrared portion of Earth's longwave spectrum as a balloon borne instrument and later was reconfigured to operate as a ground-based instrument. In its current ground-based configuration FIRST was deployed at 17500 ft on Cerro Toco, a mountain in the Atacama Desert of Chile, from August to October, 2009. There the integrated precipitable water (IPW) was as low as 0.02 cm. FIRST measurements from days with IPW between 0.024 and 0.035 cm during the campaign are presented here between 200 cm-1 and 800 cm-1. Significant spectral development in the far-IR is observed over the entire 200 cm-1 to 800 cm-1 band. Water vapor and temperature profiles from radiosonde and GVRP measurements are used as inputs to the AER Line-by-Line Radiative Transfer Model (LBLRTM) utilizing the AER v3.2 line parameter database. Uncertainties in both the measured and modeled radiances are accounted for in this study. The residual LBLRTM - FIRST is calculated to assess agreement between the measured and modeled spectra. Measured and model radiances generally agree to within the combined uncertainties for wavenumbers greater than 360 cm-1. At wavenumbers less than 360 cm-1 persistent troughs in the residual are present outside of the combined uncertainties. These features are present on different days and at different water vapor amounts. Possible solutions for these features are discussed.

  9. Tunable far infrared laser spectroscopy of Van der Waals molecules in a planar supersonic jet expansion

    International Nuclear Information System (INIS)

    Busarow, K.L.

    1990-12-01

    The gas phase high resolution spectroscopic study of weakly bound clusters can provide the information necessary to develop an intermolecular potential energy surface. This surface can then be used to better understand condensed phases. In this work, a tunable far infrared laser spectrometer is used to study weakly bound dimers produced in the newly developed continuous planar supersonic jet expansion apparatus. The water dimer is an extensively studied hydrogen bonded dimer. It undergoes several tunneling motions which result in splittings and perturbations of the rovibrational energy levels. A review is presented of much of the experimental and theoretical work done on water dimer, including a description of the combined fit of all the high resolution spectroscopic results by Coudert and Hougen. Also included is a discussion of the measurement of the K = 1 lower → K = 2 lower band performed using the tunable far infrared laser/planar jet apparatus. The preliminary results from the study of CH 4 ·H 2 O will also be presented. CH 4 ·H 2 O is unique in that unlike a strongly anisotropic complex, such as the water dimer, the monomer subunits are nearly free internal rotors. Seven bands are observed which have very similar band origins and rotational constants. Two energy level diagrams are proposed which are strongly influenced by earlier ArH 2 O studies. A brief qualitative discussion of the CH 4 ·H 2 O binding energy compared to that of ArH 2 O is also included. 152 refs., 54 figs., 20 tabs

  10. Drying characteristics of rough rice by far-infrared radiation heating

    International Nuclear Information System (INIS)

    Matsuoka, T.

    1990-01-01

    The relationship between the heat radiation characteristics of a far-infrared radiation heater and the drying characteristics of rough rice was investigated to determine the basic data required for utilization of far-infrared rays for drying rough rice. Results of investigations are discussed in detail

  11. Studies on the hyperthermic effect of the body on utilization of far infrared radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Yong Wun; Cho, Chul Ku; Kim, Kyung Jung [Korea Cancer Center Hospital, Seoul (Korea, Republic of)

    1996-12-01

    This study investigated that strong heat reaction of far infrared radiation material could have the possibility for hyperthermia in patients. Objective was CaSki cell, human uterocervical cancer cell line and they observed descending effect remarkably to compare the effect of cell death by high temperature due to far infrared radiation, platelet numbers of experimental group to compare the control were increased 7 {approx} 17%, and lymphocyte numbers 20 {approx} 40 %. High acidity in tumor tissue due to the concentration of lactic acid, so the effects of far infrared had the result to the possibility to reduce the fatigue stuff. The secretion of endorphin as cerebroneuron substance than epinephrine, sympathetic nerve substance could be reduction of pain in cancer patients because of the effect of far infrared. Above data of experiment, we were found multiple the biological efficacy of far infrared about the possibility of medical utilization. (author). 10 refs., 4 tabs., 3 figs.

  12. Studies on the hyperthermic effect of the body on utilization of far infrared radiation

    International Nuclear Information System (INIS)

    Ryu, Yong Wun; Cho, Chul Ku; Kim, Kyung Jung

    1996-12-01

    This study investigated that strong heat reaction of far infrared radiation material could have the possibility for hyperthermia in patients. Objective was CaSki cell, human uterocervical cancer cell line and they observed descending effect remarkably to compare the effect of cell death by high temperature due to far infrared radiation, platelet numbers of experimental group to compare the control were increased 7 ∼ 17%, and lymphocyte numbers 20 ∼ 40 %. High acidity in tumor tissue due to the concentration of lactic acid, so the effects of far infrared had the result to the possibility to reduce the fatigue stuff. The secretion of endorphin as cerebroneuron substance than epinephrine, sympathetic nerve substance could be reduction of pain in cancer patients because of the effect of far infrared. Above data of experiment, we were found multiple the biological efficacy of far infrared about the possibility of medical utilization. (author). 10 refs., 4 tabs., 3 figs

  13. Exploring the Dynamics of Superconductors by Time-Resolved Far-Infrared Spectroscopy

    International Nuclear Information System (INIS)

    Carr, G. L.; Lobo, R. P. S. M.; LaVeigne, J.; Reitze, D. H.; Tanner, D. B.

    2000-01-01

    We have examined the recombination of excess quasiparticles in superconducting Pb by time-resolved far-infrared spectroscopy using a pulsed synchrotron source. The energy gap shift calculated by Owen and Scalapino [Phys. Rev. Lett. 28, 1559 (1972)] is directly observed, as is the associated reduction in the Cooper pair density. The relaxation process involves a two-component decay; the faster (∼200 ps) is associated with the actual (effective) recombination process, while the slower (∼10 to 100ns) is due to heat transport across the film/substrate interface. The temperature dependence of the recombination process between 0.5T c and 0.85T c is in good agreement with theory

  14. Installation And Test Of Electron Beam Generation System To Produce Far-Infrared Radiation And X-Ray Pulses

    International Nuclear Information System (INIS)

    Wichaisirimongkol, Pathom; Jinamoon, Witoon; Khangrang, Nopadon; Kusoljariyakul, Keerati; Rhodes, Michael W.; Rimjaem, Sakhorn; Saisut, Jatuporn; Chitrlada, Thongbai; Vilaithong, Thiraphat; Wiedemann, Helmut

    2005-10-01

    SURIYA project at the Fast Neutron Research Facility, Chiang Mai University, aims to establish a facility to generate femtosecond electron beams. This electron beam can be used to generate high intensity far-infrared radiation and ultra-short X-ray pulses. The main components of the system are a 3 MeV RF electron gun with a thermionic cathode, an a-magnet as a bunch compressor, and post acceleration 15-20 MeV by a linear accelerator (linac). Between the main components, there are focusing quadrupole magnets and steering magnets to maintain the electron beam within a high vacuum tube. At the end of the beam transport line, a dipole magnet has been installed to function as a beam dump and an energy spectrometer. After the installation and testing of individual major components were completed, we have been investigating the generation of the electron beam, intense far- infrared radiation and ultra short X-ray pulses

  15. Superconducting Microwave Resonator Arrays for Submillimeter/Far-Infrared Imaging

    Science.gov (United States)

    Noroozian, Omid

    Superconducting microwave resonators have the potential to revolutionize submillimeter and far-infrared astronomy, and with it our understanding of the universe. The field of low-temperature detector technology has reached a point where extremely sensitive devices like transition-edge sensors are now capable of detecting radiation limited by the background noise of the universe. However, the size of these detector arrays are limited to only a few thousand pixels. This is because of the cost and complexity of fabricating large-scale arrays of these detectors that can reach up to 10 lithographic levels on chip, and the complicated SQUID-based multiplexing circuitry and wiring for readout of each detector. In order to make substantial progress, next-generation ground-based telescopes such as CCAT or future space telescopes require focal planes with large-scale detector arrays of 104--10 6 pixels. Arrays using microwave kinetic inductance detectors (MKID) are a potential solution. These arrays can be easily made with a single layer of superconducting metal film deposited on a silicon substrate and pattered using conventional optical lithography. Furthermore, MKIDs are inherently multiplexable in the frequency domain, allowing ˜ 10 3 detectors to be read out using a single coaxial transmission line and cryogenic amplifier, drastically reducing cost and complexity. An MKID uses the change in the microwave surface impedance of a superconducting thin-film microresonator to detect photons. Absorption of photons in the superconductor breaks Cooper pairs into quasiparticles, changing the complex surface impedance, which results in a perturbation of resonator frequency and quality factor. For excitation and readout, the resonator is weakly coupled to a transmission line. The complex amplitude of a microwave probe signal tuned on-resonance and transmitted on the feedline past the resonator is perturbed as photons are absorbed in the superconductor. The perturbation can be

  16. Environmental Temperature Effect on the Far-Infrared Absorption Features of Aromatic-Based Titan's Aerosol Analogs

    Science.gov (United States)

    Gautier, Thomas; Trainer, Melissa G.; Loeffler, Mark J.; Sebree, Joshua A.; Anderson, Carrie M.

    2016-01-01

    Benzene detection has been reported in Titans atmosphere both in the stratosphere at ppb levels by remote sensing and in the thermosphere at ppm levels by the Cassini's Ion and Neutral Mass Spectrometer. This detection supports the idea that aromatic and heteroaromatic reaction pathways may play an important role in Titans atmospheric chemistry, especially in the formation of aerosols. Indeed, aromatic molecules are easily dissociated by ultraviolet radiation and can therefore contribute significantly to aerosol formation. It has been shown recently that aerosol analogs produced from a gas mixture containing a low concentration of aromatic and/or heteroaromatic molecules (benzene, naphthalene, pyridine, quinoline and isoquinoline) have spectral signatures below 500/cm, a first step towards reproducing the aerosol spectral features observed by Cassini's Composite InfraRed Spectrometer (CIRS) in the far infrared. In this work we investigate the influence of environmental temperature on the absorption spectra of such aerosol samples, simulating the temperature range to which aerosols, once formed, are exposed during their transport through Titans stratosphere. Our results show that environmental temperature does not have any major effect on the spectral shape of these aerosol analogs in the far-infrared, which is consistent with the CIRS observations.

  17. Properties and Applications of High Emissivity Composite Films Based on Far-Infrared Ceramic Powder.

    Science.gov (United States)

    Xiong, Yabo; Huang, Shaoyun; Wang, Wenqi; Liu, Xinghai; Li, Houbin

    2017-11-29

    Polymer matrix composite materials that can emit radiation in the far-infrared region of the spectrum are receiving increasing attention due to their ability to significantly influence biological processes. This study reports on the far-infrared emissivity property of composite films based on far-infrared ceramic powder. X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray powder diffractometry were used to evaluate the physical properties of the ceramic powder. The ceramic powder was found to be rich in aluminum oxide, titanium oxide, and silicon oxide, which demonstrate high far-infrared emissivity. In addition, the micromorphology, mechanical performance, dynamic mechanical properties, and far-infrared emissivity of the composite were analyzed to evaluate their suitability for strawberry storage. The mechanical properties of the far-infrared radiation ceramic (cFIR) composite films were not significantly influenced ( p ≥ 0.05) by the addition of the ceramic powder. However, the dynamic mechanical analysis (DMA) properties of the cFIR composite films, including a reduction in damping and shock absorption performance, were significant influenced by the addition of the ceramic powder. Moreover, the cFIR composite films showed high far-infrared emissivity, which has the capability of prolonging the storage life of strawberries. This research demonstrates that cFIR composite films are promising for future applications.

  18. Panchromatic spectral energy distributions of Herschel sources

    Science.gov (United States)

    Berta, S.; Lutz, D.; Santini, P.; Wuyts, S.; Rosario, D.; Brisbin, D.; Cooray, A.; Franceschini, A.; Gruppioni, C.; Hatziminaoglou, E.; Hwang, H. S.; Le Floc'h, E.; Magnelli, B.; Nordon, R.; Oliver, S.; Page, M. J.; Popesso, P.; Pozzetti, L.; Pozzi, F.; Riguccini, L.; Rodighiero, G.; Roseboom, I.; Scott, D.; Symeonidis, M.; Valtchanov, I.; Viero, M.; Wang, L.

    2013-03-01

    Combining far-infrared Herschel photometry from the PACS Evolutionary Probe (PEP) and Herschel Multi-tiered Extragalactic Survey (HerMES) guaranteed time programs with ancillary datasets in the GOODS-N, GOODS-S, and COSMOS fields, it is possible to sample the 8-500 μm spectral energy distributions (SEDs) of galaxies with at least 7-10 bands. Extending to the UV, optical, and near-infrared, the number of bands increases up to 43. We reproduce the distribution of galaxies in a carefully selected restframe ten colors space, based on this rich data-set, using a superposition of multivariate Gaussian modes. We use this model to classify galaxies and build median SEDs of each class, which are then fitted with a modified version of the magphys code that combines stellar light, emission from dust heated by stars and a possible warm dust contribution heated by an active galactic nucleus (AGN). The color distribution of galaxies in each of the considered fields can be well described with the combination of 6-9 classes, spanning a large range of far- to near-infrared luminosity ratios, as well as different strength of the AGN contribution to bolometric luminosities. The defined Gaussian grouping is used to identify rare or odd sources. The zoology of outliers includes Herschel-detected ellipticals, very blue z ~ 1 Ly-break galaxies, quiescent spirals, and torus-dominated AGN with star formation. Out of these groups and outliers, a new template library is assembled, consisting of 32 SEDs describing the intrinsic scatter in the restframe UV-to-submm colors of infrared galaxies. This library is tested against L(IR) estimates with and without Herschel data included, and compared to eightother popular methods often adopted in the literature. When implementing Herschel photometry, these approaches produce L(IR) values consistent with each other within a median absolute deviation of 10-20%, the scatter being dominated more by fine tuning of the codes, rather than by the choice of

  19. SAFARI : A Far Infrared Imaging FTS-Spectrometer for SPICA

    NARCIS (Netherlands)

    Goicoechea, J. R.; Roelfsema, P. R.; Jellema, W.; Swinyard, B. M.

    The far-IR spectral window plays host to a critical range of both spectroscopic and photometric diagnostics with which to study our Galaxy and beyond, at wavelengths completely blocked by the Earth’s atmosphere. The proposed Japanese-led IR space telescope SPICA, with its cryogenically cooled ~3.2m

  20. IRAS far-infrared colours of normal stars

    Science.gov (United States)

    Waters, L. B. F. M.; Cote, J.; Aumann, H. H.

    1987-01-01

    The analysis of IRAS observations at 12, 25, 60 and 100 microns of bright stars of spectral type O to M is presented. The objective is to identify the 'normal' stellar population and to characterize it in terms of the relationships between (B-V) and (V-/12/), between (R-I) and (V-/12/), and as a function of spectral type and luminosity class. A well-defined relation is found between the color of normal stars in the visual (B-V), (R-I) and in the IR, which does not depend on luminosity class. Using the (B-V), (V-/12/) relation for normal stars, it is found that B and M type stars show a large fraction of deviating stars, mostly with IR excess that is probably caused by circumstellar material. A comparison of IRAS colors with the Johnson colors as a function of spectral type shows good agreement except for the K0 to M5 type stars. The results will be useful in identifying the deviating stars detected with IRAS.

  1. Micro-Spec: an Integrated, Direct-Detection Spectrometer for Far-Infrared and Submillimeter Astronomy

    Science.gov (United States)

    Cataldo, Giuseppe

    2014-01-01

    The far-infrared and submillimeter portions of the electromagnetic spectrum provide a unique view of the astrophysical processes present in the early universe. Our ability to fully explore this rich spectral region has been limited, however, by the size and cost of the cryogenic spectrometers required to carry out such measurements. Micro-Spec (u-Spec) is a high-sensitivity, direct-detection spectrometer concept working in the 450-1000 micromillimeter wavelength range which will enable a wide range of flight missions that would otherwise be challenging due to the large size of current instruments with the required spectral resolution and sensitivity. The spectrometer design utilizes two internal antenna arrays, one for transmitting and one for receiving, superconducting microstrip transmission lines for power division and phase delay, and an array of microwave kinetic inductance detectors (MKIDs) to achieve these goals. The instrument will be integrated on a approximately 10 square cm silicon chip and can therefore become an important capability under the low background conditions accessible via space and high-altitude borne platforms. In this paper, an optical design methodology for Micro-Spec is presented, with particular attention given to its twodimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the maximization of the instrument resolving power and minimization of the RMS phase error on the instrument focal plane. This two-step optimization can generate geometrical configurations given specific requirements on spectrometer size, operating spectral range and performance. A point design with resolving power of 257, an RMS phase error less than 0.1 radians and four stigmatic points was developed for initial demonstration and will be the basis of future instruments with resolving power up to about 1200.

  2. Water Vapor in Titan's Stratosphere from Cassini CIRS Far-Infrared Spectra

    Science.gov (United States)

    Cottini, V.; Nixon, C. A.; Jennings, D. E.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Teanby, N. A.; Achterberg, R. K.; Bezard, B.; hide

    2012-01-01

    Here we report the measurement of water vapor in Titan's stratosphere using the Cassini Composite Infrared Spectrometer (CIRS). CIRS senses water emissions in the far infrared spectral region near 50 micron, which we have modeled using two independent radiative transfer codes. From the analysis of nadir spectra we have derived a mixing ratio of 0.14 +/- 0.05 ppb at an altitude of 97 km, which corresponds to an integrated (from 0 to 600 km) surface normalized column abundance of 3.7 +/- 1.3 1014 molecules/cm2. In the latitude range 80S to 30N we see no evidence for latitudinal variations in these abundances within the error bars. Using limb observations, we obtained mixing ratios of 0.13 +/- 0.04 ppb at an altitude of 115 km and 0.45 +/- 0.15 ppb at an altitude of 230 km, confirming that the water abundance has a positive vertical gradient as predicted by photochemical models. We have also fitted our data using scaling factors of 0.1-0.6 to these photochemical model profiles, indicating that the models over-predict the water abundance in Titan's lower stratosphere.

  3. Far infrared extinction coefficients of minerals of interest for astronomical observations

    International Nuclear Information System (INIS)

    Hasegawa, H.

    1984-01-01

    Far infrared extinction coefficients of mineral grains of interest for astronomical observations have been measured. The measured mineral species are: amorphous carbon, high temperature magnesium silicates, hydrous silicates, iron oxides, and amorphous silicates. (author)

  4. Photon-Counting Microwave Kinetic Inductance Detectors (MKIDs) for High Resolution Far-Infrared Spectroscopy

    Data.gov (United States)

    National Aeronautics and Space Administration — We are developing ultrasensitive Microwave Kinetic Inductance Detectors (MKIDs) for high resolution far-infrared spectroscopy applications, with a long-term goal of...

  5. Studies on heat transfer in agricultural products by far-infrared ray

    International Nuclear Information System (INIS)

    Liu, H.; Mohri, K.; Namba, K.

    1998-01-01

    Heat is transferred when the object being heated has temperature differences. In this research, the difference of two heating methods (far-infrared ray heating and hot wind heating) was analyzed. To compare their differences, the heat flux was measured by setting a heat flux meter beneath the surface of the object at different depths, then the heat conductivities and heat diffusion rates were analyzed. 1) Compared with hot wind, far-infrared ray heating has more heat flux before reaching a definite depth. 2) The heat conductivity and heat diffusion rates by hot wind heating have specific properties with special objects. The heat conductivity and heat diffusion rate of far-infrared heating are higher than those of hot wind heating. The differences are considered to be caused by far-infrared rays

  6. Far Infrared Spectrometry of the Cosmic Background Radiation

    Science.gov (United States)

    Mather, J. C.

    1974-01-01

    I describe two experiments to measure the cosmic background radiation near 1 mm wavelength. The first was a ground-based search for spectral lines, made with a Fabry-Perot interferometer and an InSb detector. The second is a measurement of the spectrum from 3 to 18 cm{sup -1}, made with a balloon-borne Fourier transform spectrometer. It is a polarizing Michelson interferometer, cooled in liquid helium, and operated with a germanium bolometer. I give the theory of operation, construction details, and experimental results. The first experiment was successfully completed but the second suffered equipment malfunction on its first flight. I describe the theory of Fourier transformations and give a new understanding of convolutional phase correction computations. I discuss for infrared bolometer calibration procedures, and tabulate test results on nine detectors. I describe methods of improving bolometer sensitivity with immersion optics and with conductive film blackening.

  7. Focal plane optics in far-infrared and submillimeter astronomy

    Science.gov (United States)

    Hildebrand, R. H.

    1985-01-01

    The construction of airborne observatories, high mountain-top observatories, and space observatories designed especially for infrared and submillimeter astronomy has opened fields of research requiring new optical techniques. A typical far-IR photometric study involves measurement of a continuum spectrum in several passbands between approx 30 microns and 1000 microns and diffraction-limited mapping of the source. At these wavelengths, diffraction effects strongly influence the design of the field optics systems which couple the incoming flux to the radiation sensors (cold bolometers). The Airy diffraction disk for a typical telescope at submillimeter wavelengths approx 100 microns-1000 microns is many millimeters in diameter; the size of the field stop must be comparable. The dilute radiation at the stop is fed through a Winston nonimaging concentrator to a small cavity containing the bolometer. The purpose of this paper is to review the principles and techniques of infrared field optics systems, including spectral filters, concentrators, cavities, and bolometers (as optical elements), with emphasis on photometric systems for wavelengths longer than 60 microns.

  8. Focal plane optics in far-infrared and submillimeter astronomy

    Science.gov (United States)

    Hildebrand, R. H.

    1986-02-01

    The construction of airborne observatories, high mountain-top observatories, and space observatories designed especially for infrared and submillimeter astronomy has opened fields of research requiring new optical techniques. A typical far-IR photometric study involves measurement of a continuum spectrum in several passbands between approx 30 microns and 1000 microns and diffraction-limited mapping of the source. At these wavelengths, diffraction effects strongly influence the design of the field optics systems which couple the incoming flux to the radiation sensors (cold bolometers). The Airy diffraction disk for a typical telescope at submillimeter wavelengths approx 100 microns-1000 microns is many millimeters in diameter; the size of the field stop must be comparable. The dilute radiation at the stop is fed through a Winston nonimaging concentrator to a small cavity containing the bolometer. The purpose of this paper is to review the principles and techniques of infrared field optics systems, including spectral filters, concentrators, cavities, and bolometers (as optical elements), with emphasis on photometric systems for wavelengths longer than 60 microns.

  9. BETTII: The Balloon Experimental Twin Telescope for Infrared Interferometry (Phase 2a)- High Angular Resolution Astronomy at Far-Infrared Wavelengths

    Science.gov (United States)

    Rinehart, Stephen

    The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an eight-meter baseline far-infrared interferometer to fly on a high altitude balloon. The combination of the long baseline with a double-Fourier instrument allows BETTII to simultaneously gain both spatial and spectral information; BETTII is designed for spatially-resolved spectroscopy. The unique data obtained with BETTII will be valuable for understanding how stars form within dense clusters, by isolating individual objects that are unresolved by previous space telescopes and my measuring their spectral energy distributions. BETTII will be also used in future flights to understand the processes in the cores of Active Galactic Nuclei. In addition to these scientific goals, BETTII serves as a major step towards achieving the vision of space-based interferometry. BETTII was first funded through the 2010 APRA program; last year, the proposal also fared well in the APRA review, but for programmatic reasons was only awarded one year of funding. With the current funding, we will complete the BETTII experiment and conduct a Commissioning Flight in August/September 2016. The effort proposed includes full analysis of data from the Commissioning Flight, which will help us determine the technical and scientific capabilities of the experiment. It also includes two science flights, one in each 2017 and 2018, with full data analysis being completed in 2019.

  10. OH far-infrared emission from low- and intermediate-mass protostars surveyed with Herschel-PACS

    DEFF Research Database (Denmark)

    Wampfler, Susanne Franziska; Bruderer, S.; Karska, A.

    2013-01-01

    fluxes nor their broad line widths, strongly suggesting an outflow origin. Slab excitation models indicate that the observed excitation temperature can either be reached if the OH molecules are exposed to a strong far-infrared continuum radiation field or if the gas temperature and density...... are sufficiently high. Using realistic source parameters and radiation fields, it is shown for the case of Ser SMM1 that radiative pumping plays an important role in transitions arising from upper level energies higher than 300 K. The compact emission in the low-mass sources and the required presence of a strong...

  11. Far-infrared line images of dwarf galaxies

    Science.gov (United States)

    Poglitsch, A.; Geis, N.; Herrmann, F.; Madden, S. C.; Stacey, G. J.; Townes, C. H.; Genzel, R.

    1993-01-01

    Irregular dwarf galaxies are about ten times more widespread in the universe than regular spiral galaxies. They are characterized by a relatively low metallicity, i.e., lower abundance of the heavier elements (metals) with respect to hydrogen than in the solar neighborhood. These heavier elements in the form of molecules, atoms, or ions, which have radiative transitions in the infrared play a decisive role in the energy balance of the ISM and thereby for the formation of stars. Dwarf galaxies are thus model cases for the physical conditions in the early phase of the universe. Large Magellanic Cloud: 30 Doradus. The two nearest dwarf galaxies are the Magellanic clouds at a distance approximately 50 kpc. The LMC contains 30 Dor, a region with young, extremely massive stars which strongly interact with the surrounding ISM on account of their stellar winds and intense UV radiation. 30 Dor is the brightest object in the LMC at almost all wavelengths.

  12. Thin-layer catalytic far-infrared radiation drying and flavour of tomato slices

    Directory of Open Access Journals (Sweden)

    Ernest Ekow Abano

    2014-06-01

    Full Text Available A far-infrared radiation (FIR catalytic laboratory dryer was designed by us and used to dry tomato. The kinetics of drying of tomato slices with FIR energy was dependent on both the distance from the heat source and the sample thickness. Numerical evaluation of the simplified Fick’s law for Fourier number showed that the effective moisture diffusivity increased from 0.193×10–9 to 1.893×10–9 m2/s, from 0.059×10–9 to 2.885×10–9 m2/s, and, from 0.170×10–9 to 4.531×10–9 m2/s for the 7, 9, and 11 mm thick slices as moisture content decreased. Application of FIR enhanced the flavour of the dried tomatoes by 36.6% when compared with the raw ones. The results demonstrate that in addition to shorter drying times, the flavour of the products can be enhanced with FIR. Therefore, FIR drying should be considered as an efficient drying method for tomato with respect to minimization of processing time, enhancement in flavour, and improvements in the quality and functional property of dried tomatoes.

  13. Computed tomographic analysis of vegetable during far infrared radiation drying process

    International Nuclear Information System (INIS)

    Maneechot, P.; Tojo, S.; Watanabe, K.

    2006-01-01

    Far Infrared Radiation (FIR) technology is widely used in the automotive industry to cure painted finishes during manufacturing. FIR drying is used not only in manufacturing but also in agricultural processing such as rice drying. At the present time, FIR drying technology has rarely been used for fruits and vegetables except in research laboratories. In this study, FIR drying and hot air convection drying were compared with respect to energy consumption and time requirement. The internal changes of the agricultural product were also observed during the FIR drying process. A Computed Tomographic (CT) scanner was employed for the observation of the tested material, carrot, and was used to analyze the structural deformation and the internal moisture distribution of the test material. CT data and the hardness of the sample were recorded at regular intervals during the drying experiment. For 200, 400 and 600W FIR drying, the maximum drying rates were 173, 459 and 724%d.b./hr respectively, and the required drying times were 26, 12 and 4.5 hours, respectively. The structure of the carrot sample shrank in accordance with the reduction of moisture content in 200W FIR drying as well as in hot air drying, whereas in 400W and 600W FIR drying the sample was dried without so much deformation

  14. Synchrotron far-infrared spectroscopy of the two lowest fundamental modes of 1,1-difluoroethane

    Science.gov (United States)

    Wong, Andy; Thompson, Christopher D.; Appadoo, Dominique R. T.; Plathe, Ruth; Roy, Pascale; Manceron, Laurent; Barros, Joanna; McNaughton, Don

    2013-08-01

    The far-infrared (FIR) spectrum (50-600 cm-1) of 1,1-difluoroethane was recorded using the high-resolution infrared AILES beamline at the Soleil synchrotron. A ro-vibrational assignment was performed on the lowest wavenumber, low intensity 181 0 and 171 0 modes, yielding band centres of 224.241903 (10) cm-1 and 384.252538 (13) cm-1, respectively. A total of 965 and 2031 FIR transitions were assigned to the 181 0 and 171 0 fundamentals, respectively. Previously measured pure rotational transitions from the upper states were included into the respective fits to yield improved rotational and centrifugal distortion constants. The 182 1 hot band was observed within the fundamental band, with 369 FIR transitions assigned and co-fitted with the fundamental to give a band centre of 431.956502 (39) cm-1 for ν 18 = 2. The 182 0 overtone was observed with 586 transitions assigned and fitted to give a band centre of 431.952763 (23) cm-1 for ν 18 = 2. The difference in energy is attributed to a torsional splitting of 0.003740 (45) cm-1 in the ν 18 = 2 state. Two hot bands originating from the ν 18 = 1 and ν 17 = 1 states were observed within the 171 0 fundamental.

  15. Generation of tunable coherent far-infrared radiation using atomic Rydberg states

    International Nuclear Information System (INIS)

    Bookless, W.

    1980-12-01

    A source of tunable far-infrared radiation has been constructed. The system has been operated at 91.6 cm -1 with a demonstrated tunability of .63 cm -1 . The system is based on a Rydberg state transition in optically pumped potassium vapor. The transition energy is tuned by the application of an electric field to the excited vapor. The transition wavelength and the shifted wavelength were detected and measured by the use of a Michelson interferometer and a liquid helium cooled Ga:Ge bolometer and the data was reduced using Fast Fourier transform techniques. Extensive spectroscopy was done on the potassium vapor to elucidate the depopulation paths and rates of the excited levels. Both theoretical and experimental results are presented to support the conclusions of the research effort. Additionally, possible alternative approaches to the population of the excited state are explored and recommendations are made for the future development of this source as well as the potential uses of it in molecular spectroscopy

  16. ATR and transmission analysis of pigments by means of far infrared spectroscopy.

    Science.gov (United States)

    Kendix, Elsebeth L; Prati, Silvia; Joseph, Edith; Sciutto, Giorgia; Mazzeo, Rocco

    2009-06-01

    In the field of FTIR spectroscopy, the far infrared (FIR) spectral region has been so far less investigated than the mid-infrared (MIR), even though it presents great advantages in the characterization of those inorganic compounds, which are inactive in the MIR, such as some art pigments, corrosion products, etc. Furthermore, FIR spectroscopy is complementary to Raman spectroscopy if the fluorescence effects caused by the latter analytical technique are considered. In this paper, ATR in the FIR region is proposed as an alternative method to transmission for the analyses of pigments. This methodology was selected in order to reduce the sample amount needed for analysis, which is a must when examining cultural heritage materials. A selection of pigments have been analyzed in both ATR and transmission mode, and the resulting spectra were compared with each other. To better perform this comparison, an evaluation of the possible effect induced by the thermal treatment needed for the preparation of the polyethylene pellets on the transmission spectra of the samples has been carried out. Therefore, pigments have been analyzed in ATR mode before and after heating them at the same temperature employed for the polyethylene pellet preparation. The results showed that while the heating treatment causes only small changes in the intensity of some bands, the ATR spectra were characterized by differences in both intensity and band shifts towards lower frequencies if compared with those recorded in transmission mode. All pigments' transmission and ATR spectra are presented and discussed, and the ATR method was validated on a real case study.

  17. Far Infrared spectroscopy of proteinogenic and other less common amino acids

    Science.gov (United States)

    Iglesias-Groth, S.; Cataldo, F.

    2018-05-01

    Far infrared spectroscopy is a powerful tool complementing the potential of mid infrared spectroscopy for the search and identification of organic molecules in space. The far infrared spectra of a total of 29 amino acids are reported in this study. In addition to the spectra of 20 common proteinogenic amino acids, spectra of a selection of 9 non-proteinogenic amino acids are also reported, including the 2-aminoisobutyric acid or α-aminoisobutyric acid which, with glycine, it is one of the most abundant amino acids found in meteorites. The present database of 29 far infrared spectra may serve as reference in the search for amino acids in space environments, given the new apportunities that JWST offers for mid and far IR spectroscopy.

  18. Far-infrared observations of Sagittarius B2 - reconsideration of source structure

    International Nuclear Information System (INIS)

    Thronson, H.A. Jr.; Harper, D.A.; Yerkes Observatory, Williams Bay, WI)

    1986-01-01

    New moderate-angular-resolution far-infrared observations of the Sagittarius B2 star-forming region are presented, discussed, and compared with recent radio molecular and continuum observations of this source. In contrast to previous analyses, its far-infrared spectrum is interpreted as the result of a massive frigid cloud overlying a more-or-less normal infrared source, a natural explanation for the object's previously-noted peculiarities. The characteristics derived for the obscuring cloud are similar to those found for the W51 MAIN object. Both sources have high sub-millimeter surface brightness, a high ratio of sub-millimeter to far-infrared flux, and numerous regions of molecular maser emission. 28 references

  19. Method for generation of tunable far infrared radiation from two-dimensional plasmons

    Science.gov (United States)

    Katz, Joseph (Inventor)

    1989-01-01

    Tunable far infrared radiation is produced from two-dimensional plasmons in a heterostructure, which provides large inversion-layer electron densities at the heterointerface, without the need for a metallic grating to couple out the radiation. Instead, a light interference pattern is produced on the planar surface of the heterostructure using two coherent laser beams of a wavelength selected to be strongly absorbed by the heterostructure in order to penetrate through the inversion layer. The wavelength of the far infrared radiation coupled out can then be readily tuned by varying the angle between the coherent beams, or varying the wavelength of the two interfering coherent beams, thus varying the periodicity of the photoconductivity grating to vary the wavelength of the far infrared radiation being coupled out.

  20. Spectrally selective solar energy materials

    International Nuclear Information System (INIS)

    Sikkens, M.

    1981-01-01

    The performance and properties of spectrally selective materials are considered and, in particular, the selective absorption of solar radiation by free electrons is discussed, both in a homogeneous material in which these electrons are strongly scattered, and in a composite material consisting of small metal particles in a dielectric host. Such materials can be used as selective absorbers if they are deposited as a thin film onto a metal substrate, the latter providing the required low emittance. This type of selective surfaces is produced by reactive sputtering of Ni in an Ar/CH 4 gas mixture. This method can yield Ni films with a considerable carbon concentration. The carbon concentration can be varied over a wide range by adjusting the partial methane pressure. The associated experimental techniques are discussed. As the carbon concentration increases, the structure of the films changes from a Ni phase in which carbon is dissolved, via an intermediate Ni 3 C phase into an amorphous carbon phase with a high electrical resistivity in which small nickel particles are embedded. Both mechanisms of selective absorption by free electrons are observed and are found to be well described by rather simple models. The best selectivity is obtained at high carbon concentrations where the films consist of nickel particles in carbon. Depending on the film thickness and the substrate material, the solar absorptance varies between 0.78 and 0.90, while the thermal emittance varies between 0.025 and 0.04. Since the films are found to be stable at 400 0 C in vacuum, it appears that these films are good candidates for application in photothermal solar energy conversion at temperature levels around 200 0 C and higher. (Auth.)

  1. Far-infrared spectroscopy of lanthanide-based molecular magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Sabrina

    2015-05-13

    This thesis demonstrates the applicability of far-infrared spectroscopy for the study of the crystal-field splitting of lanthanides in single-molecular magnetic materials. The far-infrared studies of three different kinds of single-molecular-magnetic materials, a single-ion magnet, a single-chain magnet and an exchange-coupled cluster, yielded a deeper understanding of the crystal-field splitting of the lanthanides in these materials. In addition, our results offered the opportunity to gain a deeper insight into the relaxation processes of these materials.

  2. Contribution of water dimer absorption to the millimeter and far infrared atmospheric water continuum

    Science.gov (United States)

    Scribano, Yohann; Leforestier, Claude

    2007-06-01

    We present a rigorous calculation of the contribution of water dimers to the absorption coefficient α(ν¯,T ) in the millimeter and far infrared domains, over a wide range (276-310K) of temperatures. This calculation relies on the explicit consideration of all possible transitions within the entire rovibrational bound state manifold of the dimer. The water dimer is described by the flexible 12-dimensional potential energy surface previously fitted to far IR transitions [C. Leforestier et al., J. Chem. Phys. 117, 8710 (2002)], and which was recently further validated by the good agreement obtained for the calculated equilibrium constant Kp(T) with experimental data [Y. Scribano et al., J. Phys. Chem. A. 110, 5411 (2006)]. Transition dipole matrix elements were computed between all rovibrational states up to an excitation energy of 750cm-1, and J =K=5 rotational quantum numbers. It was shown by explicit calculations that these matrix elements could be extrapolated to much higher J values (J=30). Transitions to vibrational states located higher in energy were obtained from interpolation of computed matrix elements between a set of initial states spanning the 0-750cm-1 range and all vibrational states up to the dissociation limit (˜1200cm-1). We compare our calculations with available experimental measurements of the water continuum absorption in the considered range. It appears that water dimers account for an important fraction of the observed continuum absorption in the millimeter region (0-10cm-1). As frequency increases, their relative contribution decreases, becoming small (˜3%) at the highest frequency considered ν¯=944cm-1.

  3. Globules and pillars in Cygnus X. I. Herschel far-infrared imaging of the Cygnus OB2 environment

    Science.gov (United States)

    Schneider, N.; Bontemps, S.; Motte, F.; Blazere, A.; André, Ph.; Anderson, L. D.; Arzoumanian, D.; Comerón, F.; Didelon, P.; Di Francesco, J.; Duarte-Cabral, A.; Guarcello, M. G.; Hennemann, M.; Hill, T.; Könyves, V.; Marston, A.; Minier, V.; Rygl, K. L. J.; Röllig, M.; Roy, A.; Spinoglio, L.; Tremblin, P.; White, G. J.; Wright, N. J.

    2016-06-01

    The radiative feedback of massive stars on molecular clouds creates pillars, globules and other features at the interface between the H II region and molecular cloud. Optical and near-infrared observations from the ground as well as with the Hubble or Spitzer satellites have revealed numerous examples of such cloud structures. We present here Herschel far-infrared observations between 70 μm and 500 μm of the immediate environment of the rich Cygnus OB2 association, performed within the Herschel imaging survey of OB Young Stellar objects (HOBYS) program. All of the observed irradiated structures were detected based on their appearance at 70 μm, and have been classified as pillars, globules, evaporating gasous globules (EGGs), proplyd-like objects, and condensations. From the 70 μm and 160 μm flux maps, we derive the local far-ultraviolet (FUV) field on the photon dominated surfaces. In parallel, we use a census of the O-stars to estimate the overall FUV-field, that is 103-104 G0 (Habing field) close to the central OB cluster (within 10 pc) and decreases down to a few tens G0, in a distance of 50 pc. From a spectral energy distribution (SED) fit to the four longest Herschel wavelengths, we determine column density and temperature maps and derive masses, volume densities and surface densities for these structures. We find that the morphological classification corresponds to distinct physical properties. Pillars and globules are massive (~500 M⊙) and large (equivalent radius r ~ 0.6 pc) structures, corresponding to what is defined as "clumps" for molecular clouds. EGGs and proplyd-likeobjects are smaller (r ~ 0.1 and 0.2 pc) and less massive (~10 and ~30 M⊙). Cloud condensations are small (~0.1 pc), have an average mass of 35 M⊙, are dense (~6 × 104 cm-3), and can thus be described as molecular cloud "cores". All pillars and globules are oriented toward the Cyg OB2 association center and have the longest estimated photoevaporation lifetimes, a few million

  4. Theoretical considerations and preparatory experiments for poloidal field measurements in tokamaks by far-infrared polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, W; Dodel, G [Stuttgart Univ. (TH) (Germany, F.R.). Inst. fuer Plasmaforschung

    1978-12-01

    Numerical calculations give an optimum wavelength and show the precision requirements for determining poloidal field profiles in tokamaks on the basis of the Faraday effect. The required precision of the polarimetric measurements can be achieved in the far-infrared as is verified in a model experiment using a ferrite modulated HCN laser beam.

  5. Experimental test of far-infrared polarimetry for Faraday rotation measurements on the TFR 600 Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Soltwisch, H [Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.). Inst. fuer Plasmaphysik; Association Euratom-Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.)); Equipe, T F.R. [Association Euratom-CEA sur la Fusion, Centre d' Etudes Nucleaires de Fontenay-aux-Roses, 92 (France). Dept. de Recherches sur la Fusion Controlee

    1981-09-01

    The results are reported on the feasibility of using far-infrared polarimetry for Faraday rotation diagnostic measurements on the TRF Tokamak. Precise quantitative results were not obtained but a satisfactory agreement with a simple theoretical model leads to a good understanding of the experimental limitations of the method.

  6. Effect of rare earth Ce on the far infrared radiation property of iron ore tailings ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jie [Key Laboratory of Special Functional Materials for Ecological Environment and Information (Hebei University of Technology), Ministry of Education, Tianjin 300130 (China); Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130 (China); Meng, Junping, E-mail: srlj158@sina.com [Key Laboratory of Special Functional Materials for Ecological Environment and Information (Hebei University of Technology), Ministry of Education, Tianjin 300130 (China); Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130 (China); Liang, Jinsheng; Duan, Xinhui [Key Laboratory of Special Functional Materials for Ecological Environment and Information (Hebei University of Technology), Ministry of Education, Tianjin 300130 (China); Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130 (China); Huo, Xiaoli [Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130 (China); Tang, Qingguo [Key Laboratory of Special Functional Materials for Ecological Environment and Information (Hebei University of Technology), Ministry of Education, Tianjin 300130 (China); Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130 (China)

    2015-06-15

    Highlights: • Detailed process proposed for preparation of iron ore tailings ceramics. • Replace natural minerals with iron ore tailings as raw materials for preparing functional ceramics. • Impact mechanism of Ce on far infrared ceramics, as well as its optimum addition amounts can be obtained. • Propose a new perspective on considering the mechanism of far infrared radiation. - Abstract: A kind of far infrared radiation ceramics was prepared by using iron ore tailings, CaCO{sub 3} and SiO{sub 2} as main raw materials, and Ce as additive. The result of Fourier transform infrared spectroscopy showed that the sample exhibits excellent radiation value of 0.914 when doping 7 wt.% Ce. Ce{sup 4+} dissolved into iron diopside and formed interstitial solid solution with it sintered at 1150 °C. The oxidation of Fe{sup 2+} to Fe{sup 3+} caused by Ce{sup 4+} led to a decrease of crystallite sizes and enhancement of Mg–O and Fe–O vibration in iron diopside, which consequently improved the far infrared radiation properties of iron ore tailings ceramics.

  7. Far infrared and terahertz spectroscopy of ferroelectric soft modes in thin films: a review

    Czech Academy of Sciences Publication Activity Database

    Petzelt, Jan; Kamba, Stanislav

    2016-01-01

    Roč. 503, č. 1 (2016), s. 19-44 ISSN 0015-0193 R&D Projects: GA ČR GA15-08389S Institutional support: RVO:68378271 Keywords : soft mode * central mode * ferroelectric thin film * terahertz spectroscopy * far-infrared spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.551, year: 2016

  8. The Far-Infrared Radio Correlation at High-z : Prospects for the SKA

    NARCIS (Netherlands)

    Murphy, Eric J.

    2009-01-01

    In this conference proceedings article I summarize the recent work of Murphy (2009) which presents physically motivated predictions for the evolution of the Far-Infrared--radio correlation as a function of redshift arising from variations in the cosmic-ray (CR) electron cooling time-scales as

  9. ISO far-infrared observations of rich galaxy clusters II. Sersic 159-03

    DEFF Research Database (Denmark)

    Hansen, Lene; Jørgensen, H.E.; Nørgaard-Nielsen, Hans Ulrik

    2000-01-01

    In a series of papers we investigate far-infrared emission from rich galaxy clusters. Maps have been obtained by ISO at 60 mu m, 100 mu m, 135 mu m, and 200 mu m using the PHT-C camera. Ground based imaging and spectroscopy were also acquired. Here we present the results for the cooling flow...

  10. ISO far-infrared observations of rich galaxy clusters I. Abell 2670

    DEFF Research Database (Denmark)

    Hansen, Lene; Jorgensen, H.E.; Nørgaard-Nielsen, Hans Ulrik

    1999-01-01

    As part of an investigation of far-infrared emission from rich galaxy clusters the central part of Abell 2670 has been mapped with ISO at 60 mu m, 100 mu m, 135 mu m, and 200 mu m using the PHT-C camera. Point sources detected in the field have infrared fluxes comparable to normal spirals...

  11. Advancing toward far-infrared interferometry in space through coordinated international efforts

    NARCIS (Netherlands)

    Leisawitz, D.; Baryshev, A.; Griffin, M. J.; Helmich, F. P.; Ivison, R. J.; Rinehart, S. A.; Savini, G.; Shibai, H.

    2013-01-01

    The international far-infrared astrophysics community is eager to follow up Spitzer and Herschel observations with sensitive, high-resolution imaging and spectroscopy, for such measurements are needed to understand merger-driven star formation, Active Galactic Nuclei, chemical enrichment in

  12. Plasma diagnostics in infrared and far-infrared range for Heliotron E

    International Nuclear Information System (INIS)

    Sudo, S.; Zushi, H.; Hondo, K.; Takeiri, Y.; Sano, F.; Besshou, S.; Suematsu, H.; Motojima, O.; Iiyoshi, A.; Muraoka, K.; Tsukishima, T.; Tsunawaki, Y.

    1989-01-01

    In this paper diagnostics in infrared and far-infrared range for Heliotron E are described: FIR interferometer for measuring electron density profile and ECE for electron temperature profile as routine work, and Fraunhofer diffraction method with a CO 2 laser for density fluctuation and Thomson scattering with a D 2 O laser (λ = 385 μm) for ion temperature, as new methods

  13. Infrared Line Intensities for Formaldehyde from Simultaneous Measurements in the Infrared and Far Infrared Spectral Ranges

    Science.gov (United States)

    Fissiaux, L.; Földes, T.; Tchana, F. Kwabia; Daumont, L.; Lepère, M.; Vander Auwera, J.

    2011-06-01

    Formaldehyde (H_2CO) is an important intermediate compound in the degradation of the volatile organic compounds (VOCs), including methane, in the terrestrial troposphere. Its observation using optical remote sensing in the infrared range relies on the 3.6 and 5.7 μm absorption bands. Band and individual line intensities have been reported in both ranges. With the present work, we aim to also derive infrared line intensities for formaldehyde, however relying on pure rotation line intensities and the known electric dipole moment to determine the particle density. Indeed, because formaldehyde polymerizes or degrades easily, the gas phase may contain polymerization or degradation products. Spectra of H_2CO diluted in 10 hPa of N_2 were therefore simultaneously recorded in the 20-60 Cm-1 and 3.6 μm ranges, respectively using a Bruker IFS125HR Fourier transform spectrometer and a tunable diode laser. see A. Perrin, D. Jacquemart, F. Kwabia Tchana, N. Lacome, J. Quant. Spectrosc. Radiat. Transfer 110 (2009) 700-716, and references therein

  14. Motivation and Prospects for Spatio-spectral Interferometry in the Far-infrared

    Science.gov (United States)

    Leisawitz, David

    2013-01-01

    Consensus developed through a series of workshops, starting in 1998. Compelling science case for high angular resolution imaging and spectroscopy, and mission concepts. A robust plan - it has evolved over the years, but has consistently called for high resolution.

  15. Far infrared radiation promotes rabbit renal proximal tubule cell proliferation and functional characteristics, and protects against cisplatin-induced nephrotoxicity.

    Science.gov (United States)

    Chiang, I-Ni; Pu, Yeong-Shiau; Huang, Chao-Yuan; Young, Tai-Horng

    2017-01-01

    Far infrared radiation, a subdivision of the electromagnetic spectrum, is beneficial for long-term tissue healing, anti-inflammatory effects, growth promotion, sleep modulation, acceleration of microcirculation, and pain relief. We investigated if far infrared radiation is beneficial for renal proximal tubule cell cultivation and renal tissue engineering. We observed the effects of far infrared radiation on renal proximal tubules cells, including its effects on cell proliferation, gene and protein expression, and viability. We also examined the protective effects of far infrared radiation against cisplatin, a nephrotoxic agent, using the human proximal tubule cell line HK-2. We found that daily exposure to far infrared radiation for 30 min significantly increased rabbit renal proximal tubule cell proliferation in vitro, as assessed by MTT assay. Far infrared radiation was not only beneficial to renal proximal tubule cell proliferation, it also increased the expression of ATPase Na+/K+ subunit alpha 1 and glucose transporter 1, as determined by western blotting. Using quantitative polymerase chain reaction, we found that far infrared radiation enhanced CDK5R1, GNAS, NPPB, and TEK expression. In the proximal tubule cell line HK-2, far infrared radiation protected against cisplatin-mediated nephrotoxicity by reducing apoptosis. Renal proximal tubule cell cultivation with far infrared radiation exposure resulted in better cell proliferation, significantly higher ATPase Na+/K+ subunit alpha 1 and glucose transporter 1 expression, and significantly enhanced expression of CDK5R1, GNAS, NPPB, and TEK. These results suggest that far infrared radiation improves cell proliferation and differentiation. In HK-2 cells, far infrared radiation mediated protective effects against cisplatin-induced nephrotoxicity by reducing apoptosis, as indicated by flow cytometry and caspase-3 assay.

  16. Estimation of leaf water content from far infrared (2.5-14µm) spectra using continuous wavelet analysis

    NARCIS (Netherlands)

    Ullah, S.; Skidmore, A.K.; Naeem, M.; Schlerf, M.

    2012-01-01

    The objective of this study was to estimate leaf water content based on continuous wavelet analysis from the far infrared (2.5 - 14.0 μm) spectra. The entire dataset comprised of 394 far infrared spectra which were divided into calibration (262 spectra) and validation (132 spectra) subsets. The far

  17. New far infrared images of bright, nearby, star-forming regions

    Science.gov (United States)

    Harper, D. AL, Jr.; Cole, David M.; Dowell, C. Darren; Lees, Joanna F.; Lowenstein, Robert F.

    1995-01-01

    Broadband imaging in the far infrared is a vital tool for understanding how young stars form, evolve, and interact with their environment. As the sensitivity and size of detector arrays has increased, a richer and more detailed picture has emerged of the nearest and brightest regions of active star formation. We present data on M 17, M 42, and S 106 taken recently on the Kuiper Airborne Observatory with the Yerkes Observatory 60-channel far infrared camera, which has pixel sizes of 17 in. at 60 microns, 27 in. at 100 microns, and 45 in. at 160 and 200 microns. In addition to providing a clearer view of the complex central cores of the regions, the images reveal new details of the structure and heating of ionization fronts and photodissociation zones where radiation form luminous stars interacts with adjacent molecular clouds.

  18. Conceptual thermal design and analysis of a far-infrared/mid-infrared remote sensing instrument

    Science.gov (United States)

    Roettker, William A.

    1992-07-01

    This paper presents the conceptual thermal design and analysis results for the Spectroscopy of the Atmosphere using Far-Infrared Emission (SAFIRE) instrument. SAFIRE has been proposed for Mission to Planet Earth to study ozone chemistry in the middle atmosphere using remote sensing of the atmosphere in the far-infrared (21-87 microns) and mid-infrared (9-16 microns) spectra. SAFIRE requires that far-IR detectors be cooled to 3-4 K and mid-IR detectors to 80 K for the expected mission lifetime of five years. A superfluid helium dewar and Stirling-cycle cryocoolers provide the cryogenic temperatures required by the infrared detectors. The proposed instrument thermal design uses passive thermal control techniques to reject 465 watts of waste heat from the instrument.

  19. A twin optically-pumped far-infrared CH3OH laser for plasma diagnostics

    International Nuclear Information System (INIS)

    Yamanaka, M.; Takeda, Y.; Tanigawa, S.; Nishizawa, A.; Noda, N.

    1979-11-01

    A twin optically-pumped far-infrared CH 3 OH laser has been constructed for use in plasma diagnostics. The anti-symmetric doublet due to the Raman-type resonant two-photon transition is reproducibly observed at 118.8 μm. With the 118.8-μm line, it is obtained from the frequency separation of the anti-symmetric doublet that the CH 3 OH absorption line center is 16 +- 1 MHz higher than the pump 9.7-μm P(36) CO 2 laser line center. It is shown that the Raman-type resonant two-photon transition is useful in order to get several-MHz phase modulation for the far-infrared laser interferometer. Some preliminary performances of this twin laser for the modulated interferometer are described. (author)

  20. Manifestation of surface phonons in far infrared reflectivity of diamond-type semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Sanchez, F.L.; Perez-Rodriguez, F. [Instituto de Fisica, Universidad Autonoma de Puebla, Apdo. Post. J-48, Puebla, Pue. 72570 (Mexico)

    2004-11-01

    The coupling of surface phonons with light at (001) surfaces of diamond-structure crystals and its manifestation in far-infrared anisotropy spectra are theoretically studied. We apply the adiabatic bond charge model to describe short-range mechanical interactions together with long-range Coulomb forces and radiation fields, and we solve the corresponding system of coupled equations for the electromagnetic field and the lattice vibrations. We calculate far-infrared normal reflectance spectra of (001) surfaces of semi-infinite diamond-type crystals. In particular, we analyse reflectance spectra for the Si(001) (2 x 1) surface, which exhibit a resonance structure associated with the excitation of surface phonon modes. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Far-infrared contraband-detection-system development for personnel-search applications

    International Nuclear Information System (INIS)

    Schellenbaum, R.L.

    1982-09-01

    Experiments have been conducted toward the development of an active near-millimeter-wave, far infrared, personnel search system for the detection of contraband. These experiments employed a microwave hybrid tee interferometer/radiometer scanning system and quasi-optical techniques at 3.3-mm wavelength to illuminate and detect the reflection from target objects against a human body background. Clothing and other common concealing materials are transport at this wavelength. Retroreflector arrays, in conjunction with a Gunn diode radiation source, were investigated to provide all-angle illumination and detection of specular reflections from unaligned and irregular-shaped objects. Results indicate that, under highly controlled search conditions, metal objects greater than or equal to 25 cm 2 can be detected in an enclosure lined with retroreflectors. Further development is required to produce a practical personnel search system. The investigation and feasibility of alternate far infrared search techniques are presented. 23 figures, 2 tables

  2. High-resolution far-infrared observations of the galactic center

    International Nuclear Information System (INIS)

    Harvey, P.M.; Campbell, M.F.; Hoffmann, W.F.

    1976-01-01

    A map at 53 μ with 17'' resolution and three-color observations at 53 μ, 100 μ, and 175 μ with approx.30'' beams of Sgr A are presented. Sagittarius A is resolved into two main sources, one associated with the cluster of strong 10 μ sources and another approx.45'' to the southwest coincident with a weak 10 μ source. The dust temperature peaks near the strong 10 μ sources, but the 100 μ and 175 μ fluxes and the far-infrared optical depth are greatest near the southwest source. The amount of dust required to explain the far-infrared emission is comparable to that observed in absorption in the near-infrared

  3. Twin optically-pumped far-infrared CH3OH laser for plasma diagnostics

    International Nuclear Information System (INIS)

    Yamanaka, M.; Takeda, Y.; Tanigawa, S.; Nishizawa, A.

    1980-01-01

    A twin optically-pumped far-infrared CH 3 OH laser has been constructed for use in plasma diagnostics. The antisymmetric doublet due to the Raman-type resonant two-photon transition is reproducibly observed at 118.8 microns. With the 118.8-micron line, it is found that CH 3 OH absorption line center is 16 + or - 1 MHz higher than the pump 9.7-micron P(36) CO 2 laser line center. It is shown that the Raman-type resonant two-photon transition is useful in order to get several MHz phase modulation for the far-infrared laser interferometer. Some preliminary performances of this twin laser for the modulated interferometer are described

  4. The Relationship Between Dynamics and Structure in the Far Infrared Absorption Spectrum of Liquid Water

    Energy Technology Data Exchange (ETDEWEB)

    Woods, K.

    2005-01-14

    Using an intense source of far-infrared radiation, the absorption spectrum of liquid water is measured at a temperature ranging from 269 to 323 K. In the infrared spectrum we observe modes that are related to the local structure of liquid water. Here we present a FIR measured spectrum that is sensitive to the low frequency (< 100cm{sup -1}) microscopic details that exist in liquid water.

  5. Far-infrared spectra of polycrystalline Ba2YCu3O/sub 9-//sub δ/

    International Nuclear Information System (INIS)

    Thomas, G.A.; Ng, H.K.; Millis, A.J.; Bhatt, R.N.; Cava, R.J.; Rietman, E.A.; Johnson, D.W. Jr.; Espinosa, G.P.; Vandenberg, J.M.

    1987-01-01

    We present far-infrared reflectivity spectra of seven samples of ceramic superconductors in the Ba-Y-Cu-O system with transition temperatures near 93 K. We find superconducting gap structures on the basis of which we estimate the ratio of twice the average gap to the transition temperature to be consistent with 3.5, but possibly higher. Questions of normal-state characterization preclude a definitive analysis

  6. Time-resolved far-infrared experiments at the National Synchrotron Light Source. Final report

    International Nuclear Information System (INIS)

    Tanner, D.B.; Reitze, D.H.; Carr, G.L.

    1999-01-01

    A facility for time-resolved infrared and far-infrared spectroscopy has been built and commissioned at the National Synchrotron Light Source. This facility permits the study of time dependent phenomena over a frequency range from 2-8000cm -1 (0.25 meV-1 eV). Temporal resolution is approximately 200 psec and time dependent phenomena in the time range out to 100 nsec can be investigated

  7. FIRBACK Far Infrared Survey with ISO: Data Reduction, Analysis and First Results

    OpenAIRE

    Dole, Herve; Lagache, Guilaine; Puget, Jean-Loup; Gispert, Richard; Aussel, H.; Bouchet, F. R.; Ciliegi, C.; Clements, D. L.; Cesarsky, C.; Desert, F-X; Elbaz, D.; Franceschini, A.; Guiderdoni, B.; Harwit, M.; Laureijs, R.

    1999-01-01

    FIRBACK is one of the deepest cosmological surveys performed in the far infrared, using ISOPHOT. We describe this survey, its data reduction and analysis. We present the maps of fields at 175 microns. We point out some first results: source identifications with radio and mid infrared, and source counts at 175 microns. These two results suggest that half of the FIRBACK sources are probably at redshifts greater than 1. We also present briefly the large follow-up program.

  8. Mode structure in an optically pumped D2O far infrared ring laser

    International Nuclear Information System (INIS)

    Yuan, D.C.; Soumagne, G.; Siegrist, M.R.

    1989-07-01

    The mode structures in an optically pumped D 2 O far infrared ring laser and a corresponding linear resonator have been compared. While single mode operation can be obtained over the whole useful pressure range in the ring structure, this is only possible at pressures greater than 8 Torr in the linear resonator case. A numerical model predicts quite well the pulse shape, pressure dependence and influence of the resonator quality in the ring cavity. (author) 12 figs., 8 refs

  9. A new software tool for computing Earth's atmospheric transmission of near- and far-infrared radiation

    Science.gov (United States)

    Lord, Steven D.

    1992-01-01

    This report describes a new software tool, ATRAN, which computes the transmittance of Earth's atmosphere at near- and far-infrared wavelengths. We compare the capabilities of this program with others currently available and demonstrate its utility for observational data calibration and reduction. The program employs current water-vapor and ozone models to produce fast and accurate transmittance spectra for wavelengths ranging from 0.8 microns to 10 mm.

  10. Atomic oxygen fine-structure splittings with tunable far-infrared spectroscopy

    Science.gov (United States)

    Zink, Lyndon R.; Evenson, Kenneth M.; Matsushima, Fusakazu; Nelis, Thomas; Robinson, Ruth L.

    1991-01-01

    Fine-structure splittings of atomic oxygen (O-16) in the ground state have been accurately measured using a tunable far-infrared spectrometer. The 3P0-3pl splitting is 2,060,069.09 (10) MHz, and the 3Pl-3P2 splitting is 4,744,777.49 (16) MHz. These frequencies are important for measuring atomic oxygen concentration in earth's atmosphere and the interstellar medium.

  11. Far-infrared phonon spectroscopy of Pb1-xMn xTe layers grown by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Romcevic, N.; Nadolny, A.J.; Romcevic, M.; Story, T.; Taliashvili, B.; Milutinovic, A.; Trajic, J.; Lusakowska, E.; Vasiljevic-Radovic, D.; Domukhovski, V.; Osinniy, V.; Hadzic, B.; Dziawa, P.

    2007-01-01

    In this paper we used far-infrared spectroscopy, reflection high energy electron diffraction (RHEED), X-ray diffraction and atomic force microscopy (AFM) to investigate structural and optical properties of Pb 1-x Mn x Te layers grown by molecular beam epitaxy (MBE). A numerical model for calculating the reflectivity coefficient for complex systems which include films, buffer layer and substrate has been applied. The infrared reflectivity spectra consist of Pb 1-x Mn x Te phonons, which exhibit intermediate one-two mode behavior, and MnTe phonons. A good agreement between calculated and experimental spectra is achieved. We registered the local distribution of Mn impurities depending on substrate type. For films growth on BaF 2 substrate we registered the orthorhombic local structure of MnTe clusters, while in the case of KCl substrate this structure is cubic. The Pb 1-x Mn x Te long wavelength optical phonons were described by the modified Genzel's model

  12. Far-infrared elastic scattering proposal for the Avogadro Project's silicon spheres

    Science.gov (United States)

    Humayun, Muhammad Hamza; Khan, Imran; Azeem, Farhan; Chaudhry, Muhammad Rehan; Gökay, Ulaş Sabahattin; Murib, Mohammed Sharif; Serpengüzel, Ali

    2018-05-01

    Avogadro constant determines the number of particles in one mole of a substance, thus relating the molar mass of the substance to the mass of this substance. Avogadro constant is related to Système Internationale base units by defining the very concept of chemical quantity. Revisions of the base units created a need to redefine the Avogadro constant, where a collaborative work called the Avogadro Project is established to employ optical interferometry to measure the diameter of high quality 100 mm silicon spheres. We propose far-infrared spectroscopy for determining the Avogadro constant by using elastic scattering from the 100 mm Avogadro Project silicon spheres. Similar spectroscopic methods are already in use in the near-infrared, relating whispering gallery modes of the 1 mm silicon spheres to the diameter of the spheres. We present numerical simulations in the far-infrared and the near-infrared, as well as spatially scaled down elastic scattering measurements in the near-infrared. These numerical and experimental results show that, the diameter measurements of 100 mm single crystal silicon spheres with elastic scattering in the far-infrared can be considered as an alternative to optical interferometry.

  13. THE EXTRAORDINARY FAR-INFRARED VARIATION OF A PROTOSTAR: HERSCHEL/PACS OBSERVATIONS OF LRLL54361

    Energy Technology Data Exchange (ETDEWEB)

    Balog, Zoltan; Detre, Örs H.; Bouwmann, Jeroen; Nielbock, Markus; Klaas, Ulrich; Krause, Oliver; Henning, Thomas [Max Planck Institute for Astronomy Königstuhl 17, Heidelberg D-69117 (Germany); Muzerolle, James [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Flaherty, Kevin [Astronomy Department, Wesleyan University, Middletown, CT 06459 (United States); Furlan, Elise [Natinal Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Gutermuth, Rob [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Juhasz, Attila [Leiden Observatory, Leiden University, Niels Bohrweg 2, NL-2333-CA Leiden (Netherlands); Bally, John [CASA, University of Colorado, CB 389, Boulder, CO 80309 (United States); Marton, Gabor, E-mail: balog@mpia.de [Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege 15-17, 1121 Budapest (Hungary)

    2014-07-10

    We report Herschel/Photodetector Array Camera and Spectrometer (PACS) photometric observations at 70 μm and 160 μm of LRLL54361—a suspected binary protostar that exhibits periodic (P = 25.34 days) flux variations at shorter wavelengths (3.6 μm and 4.5 μm) thought to be due to pulsed accretion caused by binary motion. The PACS observations show unprecedented flux variation at these far-infrared wavelengths that are well correlated with the variations at shorter wavelengths. At 70 μm the object increases its flux by a factor of six while at 160 μm the change is about a factor of two, consistent with the wavelength dependence seen in the far-infrared spectra. The source is marginally resolved at 70 μm with varying FWHM. Deconvolved images of the sources show elongations exactly matching the outflow cavities traced by the scattered light observations. The spatial variations are anti-correlated with the flux variation, indicating that a light echo is responsible for the changes in FWHM. The observed far-infrared flux variability indicates that the disk and envelope of this source is periodically heated by the accretion pulses of the central source, and suggests that such long wavelength variability in general may provide a reasonable proxy for accretion variations in protostars.

  14. Efficacy and safety of far infrared radiation in lymphedema treatment: clinical evaluation and laboratory analysis.

    Science.gov (United States)

    Li, Ke; Zhang, Zheng; Liu, Ning Fei; Feng, Shao Qing; Tong, Yun; Zhang, Ju Fang; Constantinides, Joannis; Lazzeri, Davide; Grassetti, Luca; Nicoli, Fabio; Zhang, Yi Xin

    2017-04-01

    Swelling is the most common symptom of extremities lymphedema. Clinical evaluation and laboratory analysis were conducted after far infrared radiation (FIR) treatment on the main four components of lymphedema: fluid, fat, protein, and hyaluronan. Far infrared radiation is a kind of hyperthermia therapy with several and additional benefits as well as promoting microcirculation flow and improving collateral lymph circumfluence. Although FIR therapy has been applied for several years on thousands of lymphedema patients, there are still few studies that have reported the biological effects of FIR on lymphatic tissue. In this research, we investigate the effects of far infrared rays on the major components of lymphatic tissue. Then, we explore the effectiveness and safety of FIR as a promising treatment modality of lymphedema. A total of 32 patients affected by lymphedema in stage II and III were treated between January 2015 and January 2016 at our department. After therapy, a significant decrease of limb circumference measurements was noted and improving of quality of life was registered. Laboratory examination showed the treatment can also decrease the deposition of fluid, fat, hyaluronan, and protein, improving the swelling condition. We believe FIR treatment could be considered as both an alternative monotherapy and a useful adjunctive to the conservative or surgical lymphedema procedures. Furthermore, the real and significant biological effects of FIR represent possible future applications in wide range of the medical field.

  15. Effects of intermittent CO2 convection under far-infrared radiation on vacuum drying of pre-osmodehydrated watermelon.

    Science.gov (United States)

    Chakraborty, Rajat; Mondal, Pijus

    2017-08-01

    Watermelon, a tropical seasonal fruit with high nutrient content, requires preservation through drying due to its perishable nature. Nevertheless, drying of watermelon through conventional processes has a negative impact either on the drying time or on the final product quality. In this work, osmotic dehydration of watermelon followed by far-infrared radiation-assisted vacuum drying (FIRRAVD) was optimized to develop dehydrated watermelon with minimum moisture content. Significantly, during FIRRAVD, an attempt was made to further intensify the drying rate by forced convection through intermittent CO 2 injection. Drying kinetics of each operation and physicochemical qualities of dried products were evaluated. FIRRAVD was a viable method of watermelon drying with appreciably high moisture diffusivity (D eff,m ) of 4.97 × 10 -10 to 1.49 × 10 -9 m 2 s -1 compared to conventional tray drying. Moreover, intermittent CO 2 convection during FIRRAVD (ICFIRRAVD) resulted in appreciable intensification of drying rate, with enhanced D eff,m (9.93 × 10 -10 to 1.99 × 10 -9 m 2 s -1 ). Significantly, ICFIRRAVD required less energy and approximately 16% less time compared to FIRRAVD. The quality of the final dehydrated watermelon was superior compared to conventional drying protocols. The novel CO 2 convective drying of watermelon in the presence of far-infrared radiation demonstrated an energy-efficient and time-saving operation rendering a dehydrated watermelon with acceptable quality parameters. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  16. Far-Infrared Magneto-Optical Studies in Germanium and Indium-Antimonide at High Intensities

    Science.gov (United States)

    Leung, Michael

    Observations of nonlinear magneto-optical phenomena occurring in p-type Germanium and n-type Indium Antimonide are reported. These include multi-photon ionization of impurity states, and a new observation, the magneto-photon ionization of impurity states, and a new observation, the magneto-photon drag effect. A novel source of far-infrared radiation has been used. This source uses a pulsed CO(,2) LASER to optically pump a super-radiant cell, generating light with intensities up to 100 KW/cm('2) and wavelengths from 66 (mu)m to 496 (mu)m in a pulse of 150 nanoseconds duration. The Germanium samples were doped with Gallium, which is a shallow acceptor with an ionization potential of 11 meV. At liquid Helium temperature virtually all charge carriers are bound to acceptor sites. However, the high intensity radiation unexpectedly ionizes the acceptors. This is demonstrated through measurements of photoconductivity, transmission and the photo-Hall Effect. This observation is unexpected because the photon energy is one-fourth the ionization potential. Rate equations describing sequential multiphoton excitations are in agreement with the experimental results. The intermediate states are postulated to be acceptor exciton band states. Studies of the photoexcited mobility at 496 (mu)m suggest that at non-saturating levels of photoexcitation, the primary scattering mechanism of hot holes in Germanium is by neutral impurities. A new magneto-optical effect, the magneto-photon drag effect, has been studied in both Germanium and Indium Antimonide. This is simply the absorption of momentum by free carriers, from an incident photon field. It has been found that the mechanism for this effect is different in the two materials. In Germanium, the effect occurs when carriers make optical transitions from the heavy hole band to the light hole band. Thus, the magneto-optical behavior depends heavily upon the band structure. On the other hand, a modified Drude model (independent electron

  17. Far-infrared and CO observations of NGC 6357 and regions surrounding NGC 6357 and NGC 6334

    International Nuclear Information System (INIS)

    McBreen, B.; Jaffe, D.T.; Fazio, G.G.

    1983-01-01

    We have surveyed two 1.7 square degree sections of the galactic plane at 70 μm with one-arcminute resolution. The scanned areas included the giant southern H II region complexes NGC 6357 and NGC 6334. Nineteen far-infrared sources were observed. The sources range in luminosity from 1.6 x 10 4 to 5.5 x 10 5 L/sub sun/ . We present far-infrared continuum and CO line observations of NGC 6357. Four far-infrared sources were found in this complex and for one of these sources the exciting stars are identified. We present far-infrared and CO observations of sources in the field surrounding NGC 6357 and NGC 6334. The far-infrared sources coincide frequently with CO line temperature peaks. The CO clouds which surround the far-infrared sources have similar 13 CO column densities. Two of the far-infrared sources in the field have associated OH and H 2 O maser emission and compact H II regions

  18. HERschel key program heritage: A far-infrared source catalog for the Magellanic Clouds

    Energy Technology Data Exchange (ETDEWEB)

    Seale, Jonathan P.; Meixner, Margaret; Sewiło, Marta [The Johns Hopkins University, Department of Physics and Astronomy, 366 Bloomberg Center, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Babler, Brian [Department of Astronomy, 475 North Charter St., University of Wisconsin, Madison, WI 53706 (United States); Engelbracht, Charles W.; Misselt, Karl; Montiel, Edward [Steward Observatory, University of Arizona, 933 North Cherry Ave., Tucson, AZ 85721 (United States); Gordon, Karl; Roman-Duval, Julia [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Hony, Sacha; Okumura, Koryo; Panuzzo, Pasquale; Sauvage, Marc [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Boyer, Martha L. [Observational Cosmology Laboratory, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Chen, C.-H. Rosie [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Indebetouw, Remy [National Radio Astronomy Observatory, 520 Edgemont Road Charlottesville, VA 22903 (United States); Matsuura, Mikako [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Oliveira, Joana M.; Loon, Jacco Th. van [School of Physical and Geographical Sciences, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG (United Kingdom); Srinivasan, Sundar [UPMC-CNRS UMR7095, Institute d' Astrophysique de Paris, F-75014 Paris (France); and others

    2014-12-01

    Observations from the HERschel Inventory of the Agents of Galaxy Evolution (HERITAGE) have been used to identify dusty populations of sources in the Large and Small Magellanic Clouds (LMC and SMC). We conducted the study using the HERITAGE catalogs of point sources available from the Herschel Science Center from both the Photodetector Array Camera and Spectrometer (PACS; 100 and 160 μm) and Spectral and Photometric Imaging Receiver (SPIRE; 250, 350, and 500 μm) cameras. These catalogs are matched to each other to create a Herschel band-merged catalog and then further matched to archival Spitzer IRAC and MIPS catalogs from the Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and SAGE-SMC surveys to create single mid- to far-infrared (far-IR) point source catalogs that span the wavelength range from 3.6 to 500 μm. There are 35,322 unique sources in the LMC and 7503 in the SMC. To be bright in the FIR, a source must be very dusty, and so the sources in the HERITAGE catalogs represent the dustiest populations of sources. The brightest HERITAGE sources are dominated by young stellar objects (YSOs), and the dimmest by background galaxies. We identify the sources most likely to be background galaxies by first considering their morphology (distant galaxies are point-like at the resolution of Herschel) and then comparing the flux distribution to that of the Herschel Astrophysical Terahertz Large Area Survey (ATLAS) survey of galaxies. We find a total of 9745 background galaxy candidates in the LMC HERITAGE images and 5111 in the SMC images, in agreement with the number predicted by extrapolating from the ATLAS flux distribution. The majority of the Magellanic Cloud-residing sources are either very young, embedded forming stars or dusty clumps of the interstellar medium. Using the presence of 24 μm emission as a tracer of star formation, we identify 3518 YSO candidates in the LMC and 663 in the SMC. There are far fewer far-IR bright YSOs in the SMC than the LMC

  19. HERschel key program heritage: A far-infrared source catalog for the Magellanic Clouds

    International Nuclear Information System (INIS)

    Seale, Jonathan P.; Meixner, Margaret; Sewiło, Marta; Babler, Brian; Engelbracht, Charles W.; Misselt, Karl; Montiel, Edward; Gordon, Karl; Roman-Duval, Julia; Hony, Sacha; Okumura, Koryo; Panuzzo, Pasquale; Sauvage, Marc; Boyer, Martha L.; Chen, C.-H. Rosie; Indebetouw, Remy; Matsuura, Mikako; Oliveira, Joana M.; Loon, Jacco Th. van; Srinivasan, Sundar

    2014-01-01

    Observations from the HERschel Inventory of the Agents of Galaxy Evolution (HERITAGE) have been used to identify dusty populations of sources in the Large and Small Magellanic Clouds (LMC and SMC). We conducted the study using the HERITAGE catalogs of point sources available from the Herschel Science Center from both the Photodetector Array Camera and Spectrometer (PACS; 100 and 160 μm) and Spectral and Photometric Imaging Receiver (SPIRE; 250, 350, and 500 μm) cameras. These catalogs are matched to each other to create a Herschel band-merged catalog and then further matched to archival Spitzer IRAC and MIPS catalogs from the Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and SAGE-SMC surveys to create single mid- to far-infrared (far-IR) point source catalogs that span the wavelength range from 3.6 to 500 μm. There are 35,322 unique sources in the LMC and 7503 in the SMC. To be bright in the FIR, a source must be very dusty, and so the sources in the HERITAGE catalogs represent the dustiest populations of sources. The brightest HERITAGE sources are dominated by young stellar objects (YSOs), and the dimmest by background galaxies. We identify the sources most likely to be background galaxies by first considering their morphology (distant galaxies are point-like at the resolution of Herschel) and then comparing the flux distribution to that of the Herschel Astrophysical Terahertz Large Area Survey (ATLAS) survey of galaxies. We find a total of 9745 background galaxy candidates in the LMC HERITAGE images and 5111 in the SMC images, in agreement with the number predicted by extrapolating from the ATLAS flux distribution. The majority of the Magellanic Cloud-residing sources are either very young, embedded forming stars or dusty clumps of the interstellar medium. Using the presence of 24 μm emission as a tracer of star formation, we identify 3518 YSO candidates in the LMC and 663 in the SMC. There are far fewer far-IR bright YSOs in the SMC than the LMC

  20. Far infrared polarimetry with tokamak plasmas for determination of the poloidal magnetic field distribution

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, W

    1979-01-01

    This study examines the poloidal magnetic field distribution of tokamak plasma, and the elucidation of the radial distribution of the toroidal plasma flow. A numerical and experimental determination of the poloidal field based on the Faraday effect is presented. A method is discussed for measuring the rotation of the polarization plane linear polarized electromagnetic radiation, by passing through a plasma magnetized in the direction of the radiation. The polarization behavior of a linear polarized wave passing through a tokamak plasma is presented theoretically for various wavelengths, along with the experimental investigation of a ferrite modulation procedure through the use of different far infrared detectors.

  1. b-dipole transitions in trans-HOCO observed by far infrared laser magnetic resonance

    International Nuclear Information System (INIS)

    Sears, T.J.; Radford, H.E.; Moore, M.A.

    1993-01-01

    Far infrared laser magnetic resonance spectroscopy is used to measure components of 12 rotational transitions in the ground state of the HOCO radical. The transitions are all b-dipole in character in contrast to the a-dipole rotational spectrum previously reported [Radford, Wei, and Sears, J. Chem. Phys. 97, 3989 (1992)]. The new data determine the A rotational constant to high precision and allow the determination of several centrifugal distortion constants for the first time. The hyperfine coupling in the radical leads to observable splittings in several of the observed transitions and these are used to estimate two of the four expected nonzero hyperfine parameters in the radical

  2. Bench test results on a new technique for far-infrared polarimetry

    International Nuclear Information System (INIS)

    Barry, S.; Nieswand, C.; Prunty, S.L.; Mansfield, H.M.; O'Leary, P.

    1996-11-01

    The results of bench tests performed on a new method of combined interferometry/polarimetry for the magnetic field reconstruction of tokamak plasmas is presented. In particular, the sensitivity obtained in the polarimetric measurement shows the feasibility of Faraday rotation determination approaching a precision of ±0.2 o . The method is based on an optically pumped far-infrared (FIR) laser with a rotating polarization where both the interferometric and polarimetric information is determined from phase measurements. Specific sources which introduce disturbances in the optical arrangement and which can limit the attainment of the polarimetric precision, mentioned above, are discussed. (author) 4 figs., 6 refs

  3. THE FAR-INFRARED EMISSION FROM THE Mg+-PAH SPECIES

    International Nuclear Information System (INIS)

    Bauschlicher, Charles W. Jr.; Ricca, Alessandra

    2009-01-01

    The far-infrared (FIR) spectra of several Mg + -PAH species are studied using density functional theory. The Mg + -PAH stretching mode, regardless of the polycyclic aromatic hydrocarbon (PAH) species, carries a reasonable intensity and tends to fall in a narrow range near 40 μm. Because the bands tend to fall at very similar frequencies, the average spectra of several Mg + -PAH species produce a broadband with an intensity that is about 20% of the well known C-H out-of-plane bending mode. In contrast, an average of seven large compact pure PAHs has no FIR bands that carry any significant intensity.

  4. Far-infrared laser scattering from spontaneous and driven fluctuations in the UCLA microtor tokamak

    International Nuclear Information System (INIS)

    Lee, P.; Luhmann, N.C.; Park, H. Jr.; Peebles, W.A.; Taylor, R.J.; Xu, Ying; Yu, C.X.

    1982-01-01

    A far-infrared (FIR) laser scattering system for the study of tokamak density fluctuations is described. Recent scattering data from low frequency microturbulence in high density (n >= 5 x 10 13 cm -3 ) microtor discharges are presented. In addition, the first observation and identification of internal modes generated during ICRF heating are described. The latter study directly conforms to fast wave mode conversion theory in a two-ion species plasma. In particular, the first internal observation of mode converted ion Bernstein waves in a tokamak plasma has been made. (author)

  5. THE FAR-INFRARED SPECTROSCOPY OF VERY LARGE NEUTRAL POLYCYCLIC AROMATIC HYDROCARBONS

    International Nuclear Information System (INIS)

    Ricca, Alessandra; Bauschlicher, Charles W.; Mattioda, Andrew L.; Boersma, Christiaan; Allamandola, Louis J.

    2010-01-01

    Here we report the computed far-infrared (FIR) spectra of neutral polycyclic aromatic hydrocarbon (PAH) molecules containing at least 82 carbons up to 130 carbons and with shapes going from compact round and oval-type structures to rectangular and to trapezoidal. The effects of size and shape on the FIR band positions and intensities are discussed. Using FIR data from the NASA Ames PAH IR Spectroscopic Database Version 1.1, we generate synthetic spectra that support the suggestion that the 16.4, 17.4, and 17.8 μm bands arise from PAHs.

  6. Status of Far Infrared Tangential Interferometry/Polarimetry (FIReTIP) on NSTX

    International Nuclear Information System (INIS)

    Park, H.K.; Edwards, S.; Guttadora, L.; Deng, B.; Domier, C.W.; Lee, K.C.; Johnson, M.; Luhmann, N.C. Jr.

    2000-01-01

    The Influence of paramagnetism and diamagnetism will significantly alter the vacuum toroidal magnetic field in the spherical torus. Therefore, plasma parameters dependent upon BT such as the q-profile and the local b value need an independent measurement of BT(r,t). The multi-chord Tangential Far Infrared Interferometer/Polarimeter (FIReTIP) system [1] currently under development for the National Spherical Torus Experiment (NSTX) will provide temporally and radially resolved toroidal field profile [BT(r,t)] and 2-D electron density profile [ne(r,t)] data. A two-channel interferometer will be operational this year and the full system will be ready by 2002

  7. Inhibitory Effects of Far-Infrared Ray-Emitting Belts on Primary Dysmenorrhea

    Directory of Open Access Journals (Sweden)

    Ben-Yi Liau

    2012-01-01

    Full Text Available This study investigated the therapeutic effect of the far-infrared ray-emitting belt (FIRB in the management of primary dysmenorrhea in female patients. Forty adolescent females with primary dysmenorrhea were enrolled in the study. Quantitative measurements were taken during the menstruation. Several parameters were measured and compared, including temperature, abdominal blood flow, heart rate variability, and pain assessment. Statistical analysis shows that treatment with FIRB had significant efficiency in increasing regional surface temperature and abdominal blood flow, widening standard deviation of normal-to-normal RR intervals, and reducing VRS and NRS pain scores. The application of an FIRB appears to alleviate dysmenorrhea.

  8. A Stark-tuned, far-infrared laser for high frequency plasma diagnostics

    International Nuclear Information System (INIS)

    Mansfield, D.K.; Vocaturo, M.; Guttadora, L.; Rockmore, M.; Micai, K.; Krug, P.A.

    1992-03-01

    A Stark-tuned optically pumped far-infrared methanol laser operating at 119 micrometers has been built. The laser is designed to operate at high power while exhibiting a well-separated Stark doublet. At a pump power of 65 Watts and electric field of 1 kV/cm the laser has delivered over 100 mW c.w. while exhibiting a frequency splitting of 34 MHz. These parameters indicate that this laser would be suitable for use in the present generation of modulated interferometers on large thermonuclear plasma devices. The achieved modulation frequency is more than an order of magnitude higher than could be achieved using standard techniques

  9. The Far-Infrared Luminosity Function and Star Formation Rate Density for Dust Obscured Galaxies in the Bootes Field

    Science.gov (United States)

    Calanog, Jae Alyson; Wardlow, J. L.; Fu, H.; Cooray, A. R.; HerMES

    2013-01-01

    We present the far-Infrared (FIR) luminosity function (LF) and the star-formation rate density (SFRD) for dust-obscured galaxies (DOGs) in the Bootes field at redshift 2. These galaxies are selected by having a large rest frame mid-IR to UV flux density ratio ( > 1000) and are expected to be some of the most luminous and heavily obscured galaxies in the Universe at this epoch. Photometric redshifts for DOGs are estimated from optical and mid-IR data using empirically derived low resolution spectral templates for AGN and galaxies. We use HerMES Herschel-SPIRE data to fit a modified blackbody to calculate the FIR luminosity (LFIR) and dust temperature (Td) for all DOGs individually detected in SPIRE maps. A stacking analyses was implemented to measure a median sub-mm flux of undetected DOGs. We find that DOGs have LIR and Td that are similar with the sub-millimeter galaxy (SMG) population, suggesting these two populations are related. The DOG LF and SFRD at 2 are calculated and compared to SMGs.

  10. The Far Infrared Spectrum of Thiophosgene: Analysis of the νb{2} Fundamental Band at 500 wn

    Science.gov (United States)

    McKellar, A. R. W.; Billinghurst, B. E.

    2009-06-01

    Thiophosgene (Cl_2CS) is a model system for studies of vibrational dynamics. Many hundreds of vibrational levels in the ground electronic state have been experimentally observed, allowing a detailed anharmonic force field to be developed including all six vibrational modes. But there have been no previous high resolution studies of this molecule in the infrared, presumably because its mass and multiple isotopic species result in very congested spectra. Here we report a detailed study of the strong νb{2} fundamental band (symmetric C - Cl stretch) based on a spectrum obtained using synchrotron radiation with the Bruker IFS125 FT spectrometer at the Canadian Light Source far infrared beamline. Thiophosgene is an interesting example of an accidentally near-symmetric oblate rotor. Indeed, its inertial axes switch with isotopic substitution: for ^{35}Cl_2CS, the C_{2v} symmetry axis coincides with the a inertial axis, but for ^{37}Cl_2CS, this changes to the b axis. Fortunately for us, the ground state microwave spectrum has been well studied. Even so, it has required the full spectral resolution of the present results, with observed line widths of about 0.0008 wn, to achieve a true line-by-line analysis. [1] For example: P.D. Chowdary, B. Strickler, S. Lee, and M. Gruebele, Chem. Phys. Letters 434, 182 (2007). [2] J.H. Carpenter, D.F. Rimmer, J.G. Smith, and D.H. Whiffen, J. Chem. Soc. Faraday Trans. 2 71, 1752 (1971).

  11. Far-infrared and CO observations of Cep F: Implications for star formation in Cepheus OB3

    International Nuclear Information System (INIS)

    Sargent, A.I.; van Duinen, R.J.; Nordh, H.L.; Fridlund, C.V.M.; Aalders, J.W.G.; Beintema, D.

    1983-01-01

    Observations at 80-μm and 130-μm have revealed a source of far-infrared emission in the Cep F portion of the Cepheus OB3 molecular cloud. Molecular line measurements of this region, at the CO J = 1-0 line frequency, have led to the discovery of two CO maxima. One of these coincides with the new far-infrared source. The other is at least as intense as Cep B, until now considered to be the hottest part of the cloud. There is some evidence to suggest that a second far-infrared source is associated with this hotspot. If the far-infrared emission results from the presence of embedded protostars, their location, relative to the OB association stars and to the other active region, Cep A, requires a reexamination of how stars form in the Cepheus OB3 association

  12. Effects of Somatothermal Far-Infrared Ray on Primary Dysmenorrhea: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Yu-Min Ke

    2012-01-01

    Full Text Available The purpose of this study was to assess the beneficial effects of using a far-infrared (FIR belt on the management of patients with primary dysmenorrhea. This is the first study to determine the efficacy of somatothermal FIR using a parallel-arm randomized sham-controlled and double-blinded design with objective physical evidence and psychometric self-reports. Fifty-one Taiwanese women with primary dysmenorrhea were enrolled in the study. Results indicate that there was an increased abdominal temperature of 0.6°C and a 3.27% increase in abdominal blood flow in the FIR group (wearing FIR belt compared to those in the control group (wearing sham belt. Verbal rating scale and numeric rating scale scores in the FIR group were both lower than those in the control group. Compared to the blank group (wearing no belt, the average dysmenorrhea pain duration of the FIR group was significantly reduced from 2.5 to 1.8 days, but there was no significant difference in the control group. These results demonstrate that the use of a belt made of far-infrared ceramic materials can reduce primary dysmenorrhea.

  13. High speed FPGA-based Phasemeter for the far-infrared laser interferometers on EAST

    Science.gov (United States)

    Yao, Y.; Liu, H.; Zou, Z.; Li, W.; Lian, H.; Jie, Y.

    2017-12-01

    The far-infrared laser-based HCN interferometer and POlarimeter/INTerferometer\\break (POINT) system are important diagnostics for plasma density measurement on EAST tokamak. Both HCN and POINT provide high spatial and temporal resolution of electron density measurement and used for plasma density feedback control. The density is calculated by measuring the real-time phase difference between the reference beams and the probe beams. For long-pulse operations on EAST, the calculation of density has to meet the requirements of Real-Time and high precision. In this paper, a Phasemeter for far-infrared laser-based interferometers will be introduced. The FPGA-based Phasemeter leverages fast ADCs to obtain the three-frequency signals from VDI planar-diode Mixers, and realizes digital filters and an FFT algorithm in FPGA to provide real-time, high precision electron density output. Implementation of the Phasemeter will be helpful for the future plasma real-time feedback control in long-pulse discharge.

  14. Interpreting the cosmic far-infrared background anisotropies using a gas regulator model

    Science.gov (United States)

    Wu, Hao-Yi; Doré, Olivier; Teyssier, Romain; Serra, Paolo

    2018-04-01

    Cosmic far-infrared background (CFIRB) is a powerful probe of the history of star formation rate (SFR) and the connection between baryons and dark matter across cosmic time. In this work, we explore to which extent the CFIRB anisotropies can be reproduced by a simple physical framework for galaxy evolution, the gas regulator (bathtub) model. This model is based on continuity equations for gas, stars, and metals, taking into account cosmic gas accretion, star formation, and gas ejection. We model the large-scale galaxy bias and small-scale shot noise self-consistently, and we constrain our model using the CFIRB power spectra measured by Planck. Because of the simplicity of the physical model, the goodness of fit is limited. We compare our model predictions with the observed correlation between CFIRB and gravitational lensing, bolometric infrared luminosity functions, and submillimetre source counts. The strong clustering of CFIRB indicates a large galaxy bias, which corresponds to haloes of mass 1012.5 M⊙ at z = 2, higher than the mass associated with the peak of the star formation efficiency. We also find that the far-infrared luminosities of haloes above 1012 M⊙ are higher than the expectation from the SFR observed in ultraviolet and optical surveys.

  15. Observations of far-infrared line profiles in the Orion-KL region

    International Nuclear Information System (INIS)

    Crawford, M.K.; Lugten, J.B.; Fitelson, W.; Genzel, R.; Melnick, G.; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA)

    1986-01-01

    Measurements of several far-infrared emission line profiles in the Orion-KL region are reported. The emission from the CO, OH, and forbidden O I emission lines toward the BN-KL and H2 peak 1 positions probably comes from dense, hot molecular gas in the Orion-KL shock. The CO and forbidden O I lines have similar profiles, suggesting that the high-velocity forbidden O I emission also arises in magnetohydrodynamic cloud shocks. The velocity centroids of the lines are somewhat blueshifted. The far-infrared data thus support the interpretation that the blue asymmetry of the H2 2 micron lines is not mainly due to differential dust extinction, but rather to the kinematics and geometry of the shocked gas in the Orion-KL outflow. The forbidden O I and CO lines, however, have significantly less extreme blueshifted emission than the H2 lines. Both the forbidden O I 63 micron and forbidden C II 158 micron lines have features strongly supporting a common origin near the surface of the Orion molecular cloud. 28 references

  16. High resolution spectroscopy of six SOCl2 isotopologues from the microwave to the far-infrared

    Science.gov (United States)

    Martin-Drumel, M. A.; Roucou, A.; Brown, G. G.; Thorwirth, S.; Pirali, O.; Mouret, G.; Hindle, F.; McCarthy, M. C.; Cuisset, A.

    2016-02-01

    Despite its potential role as an atmospheric pollutant, thionyl chloride, SOCl2, remains poorly characterized in the gas phase. In this study, the pure rotational and ro-vibrational spectra of six isotopologues of this molecule, all detected in natural abundance, have been extensively studied from the cm-wave band to the far-infrared region by means of three complementary techniques: chirped-pulse Fourier transform microwave spectroscopy, sub-millimeter-wave spectroscopy using frequency multiplier chain, and synchrotron-based far-infrared spectroscopy. Owing to the complex line pattern which results from two nuclei with non-zero spins, new, high-level quantum-chemical calculations of the hyperfine structure played a crucial role in the spectroscopic analysis. From the combined experimental and theoretical work, an accurate semi-experimental equilibrium structure (reSE) of SOCl2 has been derived. With the present data, spectroscopy-based methods can now be applied with confidence to detect and monitor this species, either by remote sensing or in situ.

  17. Tunable far infrared laser spectroscopy of van der Waals bonds: Ar-NH3

    International Nuclear Information System (INIS)

    Gwo, Dz-Hung; California Univ., Berkeley, CA

    1989-11-01

    Hyperfine resolved vibration-rotation-tunneling spectra of Ar--NH 3 and (NH 3 ) 2 , generated in a planar supersonic jet, have been measured with the Berkeley tunable far infrared laser spectrometer. Among the seven rotationally assigned bands, one band belongs to Ar--NH 3 , and the other six belong to (NH 3 ) 2 . To facilitate the intermolecular vibrational assignment for Ar--NH 3 , a dynamics study aided by a permutation-inversion group theoretical treatment is performed on the rovibrational levels. The rovibrational quantum number correlation between the free internal rotor limit and the semi-rigid limit is established to provide a basic physical picture of the evolution of intermolecular vibrational component states. An anomalous vibronically allowed unique Q branch vibrational band structure is predicted to exist for a near prolate binary complex containing an inverting subunit. According to the model developed in this work, the observed band of Ar--NH 3 centered at 26.470633(17) cm -1 can correlate only to either the fundamental dimeric stretching band for the A 2 states with the NH 3 inversional quantum number v i = 1, or the K a = 0 left-arrow 0 subband of the lowest internal-rotation-inversion difference band. Although the estimated nuclear quadrupole coupling constant favors a tentative assignment in terms of the first possibility, a definitive assignment will require far infrared data and a dynamical model incorporating a potential surface

  18. A mid- to far-infrared variability study of the intermediate Seyfert galaxy, Mk 6

    International Nuclear Information System (INIS)

    Clement, R.; Sembay, S.; Coe, M.J.; Hanson, C.G.

    1988-01-01

    A mid- to far-infrared (MFIR) variability study of the intermediate Seyfert galaxy, Mk 6, is presented using data from the Infrared Astronomical Satellite (IRAS). We have analysed 25 observations of this source covering a period of about 1 month. Within the expected errors, the source shows no evidence for variability and this may be an indication that there is a strong contribution to the MFIR emission from thermal re-radiation by dust. This interpretation is consistent with previous studies which suggest that the bulk of the far-infrared (30 -100 μm) emission in Seyfert galaxies originates from cool (35 - 75 K) dust associated with star formation regions in the surrounding envelope of the active nucleus. The lack of variability at 12 and 25 μm can also be readily explained by dust emission. However, in this case, the dust temperatures required to produce emission at these wavelengths makes the narrow-line region a more feasible location for the dust grains. (author)

  19. Far infrared spectroscopy of high-Tc superconductors at the National Synchrotron Light Source

    International Nuclear Information System (INIS)

    Perkowitz, S.; Williams, G.P.

    1989-01-01

    This paper reports the first far infrared transmission spectra for micron-thick films of high-T c rare-earth superconductors such as DyBaCuO, with implications for the superconducting gap. Spectra were obtained at Brookhaven's National Synchrotron Light Source, a new high-intensity, broad-band millimeter to infrared source. The National Synchrotron Light Source at Brookhaven National Laboratory, known for powerful X-ray and UV output, is also a high-intensity (10 to 1000 times above a black body), high-brightness (intensity per solid angle), broad-band, picosecond, millimeter to infrared source. These features make it valuable for far-infrared condensed matter experiments, especially those in highly absorbing or extremely small systems. A first application has been to measure very small infrared transmissions through thick bulk-like high-T c superconducting films. Preliminary measurements through films of the conventional superconductor Nb 3 Ge established techniques. These were followed by the first measurements (to the author's knowledge) through micron-thick films of high-T c rare-earth superconductors such as DyBaCuO over 10-300 cm -1 , which includes the superconducting gap according to BCS or moderately strong-coupled theory. The authors discuss the transmission evidence bearing on the existence of a gap and other important features of high-T c superconductors, and describe the synchrotron and instrumentation features which make possible these unusual measurements

  20. Using far-infrared limb brightening to probe isolated dark globules

    International Nuclear Information System (INIS)

    Leung, C.M.; O'brien, E.V.; Dubisch, R.

    1989-01-01

    The problem of radiation transport in dark globules with or without internal heat source, immersed in an isotropic incident interstellar radiation field, is solved. The phenomenon of infrared limb brightening, its dependence on cloud properties, and its observational implications are addressed. Numerical results regarding the dependence of limb brightening on total cloud opacity, luminosity of internal heat source, grain type, dust density distribution, and wavelength of emitted radiation are discussed. Observational implications concerning the use of limb brightening to place an upper limit on the luminosity of an embedded protostar and to determine the grain emissivity law in the far-infrared are examined. For sufficiently large optical depth, the limb-brightening ratio (LBR) is found to be related to the optical depth by a power-law relation in the 140-300 micron wavelength range, where thermal emission from grains peaks. By observing the LBR in this range, this power-law relationship can be exploited to determine the emissivity law of the dust grain in the far-infrared. Both the LBR and the longest wavelength for which limb brightening still occurs are related linearly to the luminosity of the central source. 37 references

  1. Tunable Far Infrared Laser Spectroscopy of Van Der Waals Bonds: Argon-Ammonia

    Science.gov (United States)

    Gwo, Dz-Hung

    Hyperfine resolved vibration-rotation-tunneling spectra of Ar-NH_3 and (NH _3)_2, generated in a planar supersonic jet, have been measured with the Berkeley tunable far infrared laser spectrometer. Among the seven rotationally assigned bands, one band belongs to Ar-NH_3, and the other six belong to (NH_3)_2 . To facilitate the intermolecular vibrational assignment for Ar-NH_3, a dynamics study aided by a permutation-inversion group theoretical treatment is performed on the rovibrational levels. The rovibrational quantum number correlation between the free internal rotor limit and the semi-rigid limit is established to provide a basic physical picture of the evolution of intermolecular vibrational component states (K_{a } manifolds). An anomalous vibronically (not just rovibronically) allowed unique Q branch vibrational band structure is predicted to exist for a near prolate binary complex containing an inverting subunit. According to the model developed in this work, the observed band of Ar-NH_3 centered at 26.470633(17) cm^{-1} can correlate only to either (1) the fundamental dimeric stretching band for the A_2 states with the NH_3 inversional quantum number v_{i} = 1, or (2) the K_{a} = 0 >=ts 0 subband of the lowest internal-rotation -inversion difference band. Although the estimated nuclear quadrupole coupling constant favors a tentative assignment in terms of the first possibility, a definitive assignment will require more far infrared data and a dynamical model incorporating a potential surface.

  2. Far-infrared spectra of yttrium-doped gold clusters Au(n)Y (n=1-9).

    Science.gov (United States)

    Lin, Ling; Claes, Pieterjan; Gruene, Philipp; Meijer, Gerard; Fielicke, André; Nguyen, Minh Tho; Lievens, Peter

    2010-06-21

    The geometric, spectroscopic, and electronic properties of neutral yttrium-doped gold clusters Au(n)Y (n=1-9) are studied by far-infrared multiple photon dissociation (FIR-MPD) spectroscopy and quantum chemical calculations. Comparison of the observed and calculated vibrational spectra allows the structures of the isomers present in the molecular beam to be determined. Most of the isomers for which the IR spectra agree best with experiment are calculated to be the energetically most stable ones. Attachment of xenon to the Au(n)Y cluster can cause changes in the IR spectra, which involve band shifts and band splittings. In some cases symmetry changes, as a result of the attachment of xenon atoms, were also observed. All the Au(n)Y clusters considered prefer a low spin state. In contrast to pure gold clusters, which exhibit exclusively planar lowest-energy structures for small sizes, several of the studied species are three-dimensional. This is particularly the case for Au(4)Y and Au(9)Y, while for some other sizes (n=5, 8) the 3D structures have an energy similar to that of their 2D counterparts. Several of the lowest-energy structures are quasi-2D, that is, slightly distorted from planar shapes. For all the studied species the Y atom prefers high coordination, which is different from other metal dopants in gold clusters.

  3. Design study of a far-infrared free electron laser with a 20 MeV RF linear accelerator

    International Nuclear Information System (INIS)

    Nakata, S.; Tsukishima, C.; Hifumi, T.; Okuda, S.; Sato, S.; Yosojima, Y.

    1991-01-01

    A FEL in the far-infrared region has been designed using a low energy RF linear accelerator. First we estimate a small signal gain from spontaneous emission using the Madey's theorem. In the calculation following effects are included: an actual field distribution (using a measured magnetic field), beam envelope in the phase space through the undulator, energy spread, and electron beam mis-alignment to the undulator axis. We have developed a code which can simulate three dimensional processes of the electron interaction with multi-mode laser fields in the undulator. From this code we could obtain the time dependent bunching process of electrons and amplification of the laser field. During the calculation we assume an electron beam of 20 MeV, 100 mA with a pulse length of 3 μs, and an undulator of 28 periods, 6 cm periodic length and 2.5 kG peak field. The results from these calculations show that the small-signal gain over 40 % can be obtained, but mis-alignment of the beam severely degrades the gain. The results also show that the output power of several MW can be obtained under the above conditions. Considering the simulation results, a FEL beam line was constructed and the beam size at the undulator was measured. And electrons were focused enough for the FEL experiment. (author)

  4. THE IMPACT OF EVOLVING INFRARED SPECTRAL ENERGY DISTRIBUTIONS OF GALAXIES ON STAR FORMATION RATE ESTIMATES

    Energy Technology Data Exchange (ETDEWEB)

    Nordon, R.; Lutz, D.; Genzel, R.; Berta, S.; Wuyts, S.; Magnelli, B.; Foerster Schreiber, N. M.; Poglitsch, A.; Popesso, P. [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, 85741 Garching (Germany); Altieri, B. [Herschel Science Centre, European Space Astronomy Centre, ESA, Villanueva de al Canada, 28691 Madrid (Spain); Andreani, P. [ESO, Karl-Schwarzschild-Str. 2, D-85748 Garching (Germany); Aussel, H.; Daddi, E. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d' Astrophysique, Bat.709, CEA-Saclay, 91191 Gif-sur-Yvette Cedex (France); Bongiovanni, A.; Cepa, J.; Perez Garcia, A. M. [Instituto de Astrofisica de Canarias, 38200 La Laguna, Tenerife (Spain); Cimatti, A. [Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, 40127 Bologna (Italy); Fadda, D. [IPAC, California Institute of Technology, Pasadena, CA 91125 (United States); Lagache, G. [Institut d' Astrophysique Spatiale (IAS), Bat 121, Universite de Paris XI, 91450 Orsay Cedex (France); Maiolino, R., E-mail: nordon@mpe.mpg.de [INAF-Osservatorio Astronomico di Roma, via di Frascati 33, 00040 Monte Porzio Catone (Italy); and others

    2012-02-01

    We combine Herschel-Photodetector Array Camera and Spectrometer (PACS) data from the PACS Evolutionary Probe (PEP) program with Spitzer 24 {mu}m and 16 {mu}m photometry and ultra deep Infrared Spectrograph (IRS) mid-infrared spectra to measure the mid- to far-infrared spectral energy distribution (SED) of 0.7 < z < 2.5 normal star-forming galaxies (SFGs) around the main sequence (the redshift-dependent relation of star formation rate (SFR) and stellar mass). Our very deep data confirm from individual far-infrared detections that z {approx} 2 SFRs are overestimated if based on 24 {mu}m fluxes and SED templates that are calibrated via local trends with luminosity. Galaxies with similar ratios of rest-frame {nu}L{sub {nu}}(8) to 8-1000 {mu}m infrared luminosity (LIR) tend to lie along lines of constant offset from the main sequence. We explore the relation between SED shape and offset in specific star formation rate (SSFR) from the redshift-dependent main sequence. Main-sequence galaxies tend to have a similar {nu}L{sub {nu}}(8)/LIR regardless of LIR and redshift, up to z {approx} 2.5, and {nu}L{sub {nu}}(8)/LIR decreases with increasing offset above the main sequence in a consistent way at the studied redshifts. We provide a redshift-independent calibration of SED templates in the range of 8-60 {mu}m as a function of {Delta}log(SSFR) offset from the main sequence. Redshift dependency enters only through the evolution of the main sequence with time. Ultra deep IRS spectra match these SED trends well and verify that they are mostly due to a change in ratio of polycyclic aromatic hydrocarbon (PAH) to LIR rather than continua of hidden active galactic nuclei (AGNs). Alternatively, we discuss the dependence of {nu}L{sub {nu}}(8)/LIR on LIR. The same {nu}L{sub {nu}}(8)/LIR is reached at increasingly higher LIR at higher redshift, with shifts relative to local by 0.5 and 0.8 dex in log(LIR) at redshifts z {approx} 1 and z {approx} 2. Corresponding SED template calibrations

  5. A hybrid type undulator for far-infrared FELs at FELI

    Energy Technology Data Exchange (ETDEWEB)

    Zako, A.; Miyauchi, Y.; Koga, A. [Free Electron Laser Research Institute, Inc., Osaka (Japan)] [and others

    1995-12-31

    Two FEL facilities of the FELI are now operating in the wavelength range of 1-20 {mu}m. A 3.2-m hybrid type undulator ({lambda}{sub u}=80mm, N=40) has been designed for far-infrared FELs and will be installed in December. It can cover the wavelength of 20-60 {mu}m by changing K-value from 1 to 2.7 for a 28.0-MeV electron beam. It is composed of ferrite magnetic poles and Sm-Co permanent magnets. Commonly wound coils induce alternating magnetic field in ferrite poles. Combination of the induced field and the permanent magnet field can controls the magnetic field between the undulator gap.

  6. A Demonstration of TIA Using FD-SOI CMOS OPAMP for Far-Infrared Astronomy

    Science.gov (United States)

    Nagase, Koichi; Wada, Takehiko; Ikeda, Hirokazu; Arai, Yasuo; Ohno, Morifumi; Hanaoka, Misaki; Kanada, Hidehiro; Oyabu, Shinki; Hattori, Yasuki; Ukai, Sota; Suzuki, Toyoaki; Watanabe, Kentaroh; Baba, Shunsuke; Kochi, Chihiro; Yamamoto, Keita

    2016-07-01

    We are developing a fully depleted silicon-on-insulator (FD-SOI) CMOS readout integrated circuit (ROIC) operated at temperatures below ˜ 4 K. Its application is planned for the readout circuit of high-impedance far-infrared detectors for astronomical observations. We designed a trans-impedance amplifier (TIA) using a CMOS operational amplifier (OPAMP) with FD-SOI technique. The TIA is optimized to readout signals from a germanium blocked impurity band (Ge BIB) detector which is highly sensitive to wavelengths of up to ˜ 200 \\upmu m. For the first time, we demonstrated the FD-SOI CMOS OPAMP combined with the Ge BIB detector at 4.5 K. The result promises to solve issues faced by conventional cryogenic ROICs.

  7. Vibration mitigation in J-TEXT far-infrared diagnostic systems

    International Nuclear Information System (INIS)

    Li, Q.; Chen, J.; Zhuang, G.; Wang, Z. J.; Gao, L.; Chen, W.

    2012-01-01

    Optical structure stability is an important issue for far-infrared (FIR) phase measurements. To ensure good signal quality, influence of vibration should be minimized. Mechanical amelioration and optical optimization can be taken in turn to decrease vibration's influence and ensure acceptable measurement. J-TEXT (Joint Texal Experiment Tokamak, formerly TEXT-U) has two FIR diagnostic systems: a HCN interferometer system for electron density measurement and a three-wave polarimeter-interferometer system (POLARIS) for electron density and Faraday effect measurements. All use phase detection techniques. HCN interferometer system has almost eliminated the influence of vibration after mechanical amelioration and optical optimization. POLARIS also obtained first experimental results after mechanical stability improvements and is expected to further reduce vibration's influence on Faraday angle to 0.1° after optical optimization.

  8. Optics Alignment of a Balloon-Borne Far-Infrared Interferometer BETTII

    Science.gov (United States)

    Dhabal, Arnab; Rinehart, Stephen A.; Rizzo, Maxime J.; Mundy, Lee; Sampler, Henry; Juanola Parramon, Roser; Veach, Todd; Fixsen, Dale; Vila Hernandez De Lorenzo, Jor; Silverberg, Robert F.

    2017-01-01

    The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-m baseline far-infrared (FIR: 30 90 micrometer) interferometer providing spatially resolved spectroscopy. The initial scientific focus of BETTII is on clustered star formation, but this capability likely has a much broader scientific application.One critical step in developing an interferometer, such as BETTII, is the optical alignment of the system. We discuss how we determine alignment sensitivities of different optical elements on the interferogram outputs. Accordingly, an alignment plan is executed that makes use of a laser tracker and theodolites for precise optical metrology of both the large external optics and the small optics inside the cryostat. We test our alignment on the ground by pointing BETTII to bright near-infrared sources and obtaining their images in the tracking detectors.

  9. Detection of OH from Comet Halley in the far-infrared

    International Nuclear Information System (INIS)

    Stacey, G.J.; Lugten, J.B.; Genzel, R.

    1986-01-01

    The 2 Pi 3/2 (J = 5/2 yields 3/2 + yields - parity) transition of OH was detected in comet Halley at 119.44 microns. The upper limit to the line intensity of the - yields + parity transition is 119.23 microns. The ratio of these lines is consistent with radiative pumping of the rotational levels through absorption of near ultraviolet solar photons which excite the low lying vibrational levels of OH. The far-infrared lines probe the inner regions of the coma where OH is produced through photodissociation of a parent molecule (presumably H 2 O). Hence, these lines complement the 18 cm radio measurements which are sensitive to the outer regions of the comet coma. The OH production rate is highly model dependent but is of the order 2 to 4 times 10 to the 29th power molecules/sec

  10. Orion star-forming region - far-infrared and radio molecular observations

    International Nuclear Information System (INIS)

    Thronson, H.A. Jr.; Harper, D.A.; Bally, J.; Dragovan, M.; Mozurkewich, D.; Yerkes Observatory, Williams Bay, WI; ATandT Bell Labs., Holmdel, NJ; Chicago Uni., IL; E. O. Hulburt Center for Space Research, Washington, DC)

    1986-01-01

    New J = 1-0 CO and far-infrared maps of the Orion star-forming region are presented and discussed. The total infrared luminosity of the Orion star-forming ridge is 250,000 solar luminosities. The material that is emitting strongly at 60 microns is traced and found to be highly centrally concentrated. However, the majority of the extended emission from this region comes from dust that is ultimately heated by the visible Trapezium cluster stars. The luminosity of IRc 2, the most luminous member of the infrared cluster, is estimated to be 40,000-50,000 solar luminosities. A schematic drawing of the Ori MC 1 region is presented. 30 references

  11. Far-infrared tangential interferometer/polarimeter design and installation for NSTX-U

    Energy Technology Data Exchange (ETDEWEB)

    Scott, E. R., E-mail: evrscott@ucdavis.edu [Department of Mechanical and Aerospace Engineering, University of California, Davis, California 95616 (United States); Barchfeld, R. [Department of Applied Science, University of California, Davis, California 95616 (United States); Riemenschneider, P.; Domier, C. W.; Sohrabi, M.; Luhmann, N. C. [Department of Electrical and Computer Engineering, University of California, Davis, California 95616 (United States); Muscatello, C. M. [General Atomics, San Diego, California 92121 (United States); Kaita, R.; Ren, Y. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States)

    2016-11-15

    The Far-infrared Tangential Interferometer/Polarimeter (FIReTIP) system has been refurbished and is being reinstalled on the National Spherical Torus Experiment—Upgrade (NSTX-U) to supply real-time line-integrated core electron density measurements for use in the NSTX-U plasma control system (PCS) to facilitate real-time density feedback control of the NSTX-U plasma. Inclusion of a visible light heterodyne interferometer in the FIReTIP system allows for real-time vibration compensation due to movement of an internally mounted retroreflector and the FIReTIP front-end optics. Real-time signal correction is achieved through use of a National Instruments CompactRIO field-programmable gate array.

  12. Design and prototype results of a far-infrared interferometer for MFTF-B

    International Nuclear Information System (INIS)

    Monjes, J.A.; Throop, A.L.; Thomas, S.R.; Peebles, A.; Zu, Qin-Zin.

    1983-01-01

    A Far-Infrared (FIR) Laser Interferometer (FLI), operating at 185 μm wavelength is planned as part of the initial start-up set of plasma diagnostics for the Mirror Fusion Test Facility (MFTF-B). The FLI will consist of a heterodyne, three-chord laser interferometer which will be used initially to measure line-integrated plasma density in the high-density, center cell region of the machine. The conceptual system design and analysis has been completed. There are several unique environmental/physical constraints and performance requirements for this system which have required that technology-evaluation and prototyping experiments be completed to support the design effort and confirm the expected performance parameters. Issues which have been addressed include extensive use of long-path dielectric waveguide, coupling and control of free-space propagation of the beam, and polarization control. The results and conclusions of the design analysis and experimental measurements will be presented

  13. A Study of the Radio Continuum Far Infrared Correlation at Small Scales in the Galaxy

    Science.gov (United States)

    Rodriguez-Martinez, Monica I.; Allen, R. J.; Wiklind, T.; Loinard, L.

    2006-12-01

    We present a study of the behavior of the Radio Continuum (RC) Far Infrared (FIR) correlation on scales corresponding to the size of small molecular clouds. This was done by comparing the spatial distribution of RC emission and FIR emission from a sample of several regions, distributed within the range 79∘ ≤ l ≤ 174∘ in the Galaxy. We have examined the 408 and 1420 MHz mosaic images of the sample, from the Canadian Galactic Plane Survey (CGPS), which later were compared with images at 60 and 100 μm. Preliminary results suggest that the RC -FIR correlation still holds at small scales, since a good qualitative correlation between RC and FIR emission is found. The physical process involved that may cause such correlation will be discussed as well as the nature of the RC emission. This research makes use of data from the Canadian Galactic Plane Survey.

  14. Hyperfine spectrum measurement of an optically pumped far-infrared laser with a Michelson interferometer

    International Nuclear Information System (INIS)

    Zuo, Z G; Ling, F R; Wang, P; Liu, J S; Yao, J Q; Weng, C X

    2013-01-01

    In this letter, we present a Michelson interferometer for the hyperfine spectrum measurement of an optically pumped far-infrared laser with a highest frequency resolution of 3–5 GHz. CH 3 OH gas with a purity of 99.9%, is pumped by the CO 2 9P36 and 9R10 laser lines to generate terahertz lasers with frequencies of 2.52 and 3.11 THz, respectively. Moreover, except for the center frequency, which is in good agreement with theoretical work, some additional frequencies on both sides of the center frequency are obtained at a frequency interval of 0.15 THz. Meanwhile, the mechanism behind the observed experimental results is also investigated. (letter)

  15. The polarization of the far-infrared radiation from the Galactic center

    Science.gov (United States)

    Werner, M. W.; Davidson, J. A.; Morris, M.; Novak, G.; Platt, S. R.

    1988-01-01

    The first detection of linear polarization of the far-infrared (100-micron) radiation from the about 3-pc-diameter dust ring surrounding the galactic nucleus is reported. The percentage of polarization is between 1 and 2 percent at the three measured positions. It is argued that the polarized radiation is produced by thermal emission from elongated interstellar grains oriented by the local magnetic field. The dust ring is optically thin at 100 microns; therefore the observations sample dust through the entire depth of the cloud and are free of confusing effects due to embedded sources, scattering, or selective absorption. These data provide the first information about the configuration of the magnetic field in the dust ring.

  16. Near-infrared observations of the far-infrared source V region in NGC 6334

    International Nuclear Information System (INIS)

    Fischer, J.; Joyce, R.R.; Simon, M.; Simon, T.

    1982-01-01

    We have observed a very red near-infrared source at the center of NGC 6334 FIRS V, a far-infrared source suspected of variability by McBreen et al. The near-infrared source has deep ice and silicate absorption bands, and its half-power size at 20 μm is approx.15'' x 10''. Over the past 2 years we have observed no variability in the near-infrared flux. We have also detected an extended source of H 2 line emission in this region. The total luminosity in the H 2 v-1--0 S(1) line, uncorrected for extinction along the line of sight, is 0.3 L/sub sun/. Detection of emission in high-velocity wings of the J = 1--0 12 CO line suggests that the H 2 emission is associated with a supersonic gas flow

  17. Drunk identification using far infrared imagery based on DCT features in DWT domain

    Science.gov (United States)

    Xie, Zhihua; Jiang, Peng; Xiong, Ying; Li, Ke

    2016-10-01

    Drunk driving problem is a serious threat to traffic safety. Automatic drunk driver identification is vital to improve the traffic safety. This paper copes with automatic drunk driver detection using far infrared thermal images by the holistic features. To improve the robustness of drunk driver detection, instead of traditional local pixels, a holistic feature extraction method is proposed to attain compact and discriminative features for infrared face drunk identification. Discrete cosine transform (DCT) in discrete wavelet transform (DWT) domain is used to extract the useful features in infrared face images for its high speed. Then, the first six DCT coefficients are retained for drunk classification by means of "Z" scanning. Finally, SVM is applied to classify the drunk person. Experimental results illustrate that the accuracy rate of proposed infrared face drunk identification can reach 98.5% with high computation efficiency, which can be applied in real drunk driver detection system.

  18. Far-infrared /FIR/ optical black bidirectional reflectance distribution function /BRDF/

    Science.gov (United States)

    Smith, S. M.

    1981-01-01

    A nonspecular reflectometer and its operation at far-infrared wavelengths are described. Large differences in nonspecular reflectance were found to exist between different optically black coatings. Normal incidence bidirectional reflectance distribution function /BRDF) measurements at wavelengths between 12 and 316 microns of three black coatings show that their mean BRDFs increase with wavelength. The specularity of two of these coatings also showed a strong wavelength dependence, while the specularity of one coating seemed independent of wavelength. The BRDF of one coating depended on the angle of incidence at 12 and 38 microns, but not at 316 microns. Beyond 200 microns, it was found necessary to correct the measurements for the beam spread of the instrument.

  19. Far-infrared imaging arrays for fusion plasma density and magnetic field measurements

    International Nuclear Information System (INIS)

    Neikirk, D.P.; Rutledge, D.B.

    1982-01-01

    Far-infrared imaging detector arrays are required for the determination of density and local magnetic field in fusion plasmas. Analytic calculations point out the difficulties with simple printed slot and dipole antennas on ungrounded substrates for use in submillimeter wave imaging arrays because of trapped surface waves. This is followed by a discussion of the use of substrate-lens coupling to eliminate the associated trapped surface modes responsible for their poor performance. This integrates well with a modified bow-tie antenna and permits diffraction-limited imaging. Arrays using bismuth microbolometers have been successfully fabricated and tested at 1222μm and 119μm. A 100 channel pilot experiment designed for the UCLA Microtor tokamak is described. (author)

  20. Observations of far-infrared molecular emission lines from the Orion molecular cloud

    International Nuclear Information System (INIS)

    Viscuso, P.J.

    1986-01-01

    The Orion Nebula has been the subject of intensive study for over one hundred years. Far-infrared (FIR) molecular line observations of CO in the shock region surrounding the infrared source IRc2 have suggested that the molecular hydrogen density in the shocked and post-shock gas is roughly 3 x 10 6 cm -3 . The temperature of this gas is on the order of 750-2000K. IRc2, like other nearby infrared sources within the Nebula, is thought to be a site of recent star formation. This object is apparently at the center of a massive bipolar molecular outflow of gas, which is producing a shock front where it meets the ambient molecular cloud surrounding IRc2. Study of such regions is important for the understanding of the chemical and physical processes that are involved in the formation of stars from molecular clouds. Recently, several far-infrared transitions among the low-lying levels of OH have been observed toward IRc2. OH is thought to be abundant, and it plays an important role in the chemical evolution of the shock and post-shock regions. The OH emission serves as a sensitive probe of the temperature and density for the shock-processed gas. A rigorous treatment of the radiative transfer of these measured transitions is performed using the escape probability formalism. From this analysis, the author determines the temperature of the OH-emitting region to be on the order of 40K. This suggests that the gas is part of the post-shock gas that has cooled sufficiently, most likely by way of radiative cooling by CO

  1. Tunable far infrared laser spectroscopy of van der Waals bonds: Ar-NH sub 3

    Energy Technology Data Exchange (ETDEWEB)

    Gwo, Dz-Hung (Lawrence Berkeley Lab., CA (USA) California Univ., Berkeley, CA (USA). Dept. of Chemistry)

    1989-11-01

    Hyperfine resolved vibration-rotation-tunneling spectra of Ar--NH{sub 3} and (NH{sub 3}){sub 2}, generated in a planar supersonic jet, have been measured with the Berkeley tunable far infrared laser spectrometer. Among the seven rotationally assigned bands, one band belongs to Ar--NH{sub 3}, and the other six belong to (NH{sub 3}){sub 2}. To facilitate the intermolecular vibrational assignment for Ar--NH{sub 3}, a dynamics study aided by a permutation-inversion group theoretical treatment is performed on the rovibrational levels. The rovibrational quantum number correlation between the free internal rotor limit and the semi-rigid limit is established to provide a basic physical picture of the evolution of intermolecular vibrational component states. An anomalous vibronically allowed unique Q branch vibrational band structure is predicted to exist for a near prolate binary complex containing an inverting subunit. According to the model developed in this work, the observed band of Ar--NH{sub 3} centered at 26.470633(17) cm{sup {minus}1} can correlate only to either the fundamental dimeric stretching band for the A{sub 2} states with the NH{sub 3} inversional quantum number v{sub i} = 1, or the K{sub a} = 0 {l arrow} 0 subband of the lowest internal-rotation-inversion difference band. Although the estimated nuclear quadrupole coupling constant favors a tentative assignment in terms of the first possibility, a definitive assignment will require far infrared data and a dynamical model incorporating a potential surface.

  2. Third harmonic generation of high power far infrared radiation in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Urban, M [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP)

    1996-04-01

    We investigated the third harmonic generation of high power infrared radiation in doped semiconductors with emphasis on the conversion efficiency. The third harmonic generation effect is based on the nonlinear response of the conduction band electrons in the semiconductor with respect to the electric field of the incident electromagnetic wave. Because this work is directed towards a proposed application in fusion plasma diagnostics, the experimental requirements for the radiation source at the fundamental frequency are roughly given as follows: a wavelength of the radiation at the fundamental frequency in the order of 1 mm and an incident power greater than 1 MW. The most important experiments of this work were performed using the high power far infrared laser of the CRPP. With this laser a new laser line was discovered, which fits exactly the source specifications given above: the wavelength is 676 {mu}m and the maximum power is up to 2 MW. Additional experiments were carried out using a 496 {mu}m laser and a 140 GHz (2.1 mm) gyrotron. The main experimental progress with respect to previous work in this field is, in addition to the use of a very high power laser, the possibility of an absolute calibration of the detectors for the far infrared radiation and the availability of a new type of detector with a very fast response. This detector made it possible to measure the power at the fundamental as well as the third harmonic frequency with full temporal resolution of the fluctuations during the laser pulse. Therefore the power dependence of the third harmonic generation efficiency could be measured directly. The materials investigated were InSb as an example of a narrow gap semiconductor and Si as standard material. The main results are: narrow gap semiconductors indeed have a highly nonlinear electronic response, but the narrow band gap leads at the same time to a low power threshold for internal breakdown, which is due to impact ionization. figs., tabs., refs.

  3. Far-Infrared and Millimeter Continuum Studies of K-Giants: Alpha Boo and Alpha Tau

    Science.gov (United States)

    Cohen, Martin; Carbon, Duane F.; Welch, William J.; Lim, Tanya; Forster, James R.; Goorvitch, David; Thigpen, William (Technical Monitor)

    2002-01-01

    We have imaged two normal, non-coronal, infrared-bright K-giants, alpha Boo and alpha Tau, in the 1.4-millimeter and 2.8-millimeter continuum using BIMA. These stars have been used as important absolute calibrators for several infrared satellites. Our goals are: (1) to probe the structure of their upper photospheres; (2) to establish whether these stars radiate as simple photospheres or possess long-wavelength chromospheres; and (3) to make a connection between millimeter-wave and far-infrared absolute flux calibrations. To accomplish these goals we also present ISO Long Wavelength Spectrometer (LWS) measurements of both these K-giants. The far-infrared and millimeter continuum radiation is produced in the vicinity of the temperature minimum in a Boo and a Tau, offering a direct test of the model photospheres and chromospheres for these two cool giants. We find that current photospheric models predict fluxes in reasonable agreement with those observed for those wavelengths which sample the upper photosphere, namely less than or equal to 170 micrometers in alpha Tau and less than or equal to 125 micrometers in alpha Boo. It is possible that alpha Tau is still radiative as far as 0.9 - 1.4 millimeters. We detect chromospheric radiation from both stars by 2.8 millimeters (by 1.4 millimeters in alpha Boo), and are able to establish useful bounds on the location of the temperature minimum. An attempt to interpret the chromospheric fluxes using the two-component "bifurcation model" proposed by Wiedemann et al. (1994) appears to lead to a significant contradiction.

  4. Effect of ultraviolet and far infrared radiation on microbial decontamination and quality of cumin seeds.

    Science.gov (United States)

    Erdoğdu, S Belgin; Ekiz, H İbrahim

    2011-01-01

    Cumin seeds might be exposed to a high level of natural bacterial contamination, and this could potentially create a public health risk besides leading to problems in exportation. Ultraviolet (UVC) and far infrared (FIR) radiation has low penetration power, and due to that, there might be no detrimental defects to the products during a possible decontamination process. Therefore, the objective of this study was to determine the effect of UVC and FIR treatment on microbial decontamination and quality of cumin seeds. For this purpose, FIR treatment at different exposure times and temperatures were applied followed by constant UVC treatment with an intensity of 10.5 mW/cm² for 2 h. Total mesophilic aerobic bacteria of the cumin seeds were decreased to the target level of 10⁴ CFU/g after 1.57, 2.8, and 4.8 min FIR treatment at 300, 250, and 200 °C, respectively, following a 2 h UVC treatment. Under the given conditions, a complete elimination for total yeast and molds were obtained while there were no significant changes in volatile oil content and color of the cumin seeds. Consequently, combined UVC and FIR treatment was determined to be a promising method for decontamination of the cumin seeds. This research attempts to apply UVC and far infrared (FIR) radiation for pasteurization of cumin seeds. The data suggested that combined UVC and FIR radiation treatments can become a promising new method for pasteurization of cumin seeds without causing any detrimental defect to the quality parameters. The results of this industry partnered (Kadioglu Baharat, Mersin, Turkey--http://www.kadioglubaharat.com) study were already applied in industrial scale production lines. © 2011 Institute of Food Technologists®

  5. Modeling the light-travel-time effect on the far-infrared size of IRC +10216

    Science.gov (United States)

    Wright, Edward L.; Baganoff, Frederick K.

    1995-01-01

    Models of the far-infrared emission from the large circumstellar dust envelope surrounding the carbon star IRC +10216 are used to assess the importance of the light-travel-time effect (LTTE) on the observed size of the source. The central star is a long-period variable with an average period of 644 +/- 17 days and a peak-to-peak amplitude of two magnituds, so a large light-travel-time effect is seen at 1 min radius. An attempt is made to use the LTTE to reconcile the discrepancy between the observations of Fazio et al. and Lester et al. regarding the far-infrared source size. This discrepancy is reviewed in light of recent, high-spatial-resolution observations at 11 microns by Danchi et al. We conclude that IRC +10216 has been resolved on the arcminute scale by Fazio et al. Convolution of the model intensity profile at 61 microns with the 60 sec x 90 sec Gaussian beam of Fazio et al. yields an observed source size full width at half maximum (FWHM) that ranges from approximately 67 sec to 75 sec depending on the phase of the star and the assumed distance to the source. Using a simple r(exp -2) dust distribution and the 106 deg phase of the Fazio et al. observations, the LTTE model reaches a peak size of 74.3 sec at a distance of 300 pc. This agrees favorably with the 78 sec x 6 sec size measured by Fazio et al. Finally, a method is outlined for using the LTTE as a distance indicator to IRC +10216 and other stars with extended mass outflows.

  6. THE HERSCHEL ORION PROTOSTAR SURVEY: SPECTRAL ENERGY DISTRIBUTIONS AND FITS USING A GRID OF PROTOSTELLAR MODELS

    Energy Technology Data Exchange (ETDEWEB)

    Furlan, E. [Infrared Processing and Analysis Center, California Institute of Technology, 770 S. Wilson Ave., Pasadena, CA 91125 (United States); Fischer, W. J. [Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Ali, B. [Space Science Institute, 4750 Walnut Street, Boulder, CO 80301 (United States); Stutz, A. M. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Stanke, T. [ESO, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei München (Germany); Tobin, J. J. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Megeath, S. T.; Booker, J. [Ritter Astrophysical Research Center, Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606 (United States); Osorio, M. [Instituto de Astrofísica de Andalucía, CSIC, Camino Bajo de Huétor 50, E-18008 Granada (Spain); Hartmann, L.; Calvet, N. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Poteet, C. A. [New York Center for Astrobiology, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Manoj, P. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India); Watson, D. M. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Allen, L., E-mail: furlan@ipac.caltech.edu [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States)

    2016-05-01

    We present key results from the Herschel Orion Protostar Survey: spectral energy distributions (SEDs) and model fits of 330 young stellar objects, predominantly protostars, in the Orion molecular clouds. This is the largest sample of protostars studied in a single, nearby star formation complex. With near-infrared photometry from 2MASS, mid- and far-infrared data from Spitzer and Herschel , and submillimeter photometry from APEX, our SEDs cover 1.2–870 μ m and sample the peak of the protostellar envelope emission at ∼100 μ m. Using mid-IR spectral indices and bolometric temperatures, we classify our sample into 92 Class 0 protostars, 125 Class I protostars, 102 flat-spectrum sources, and 11 Class II pre-main-sequence stars. We implement a simple protostellar model (including a disk in an infalling envelope with outflow cavities) to generate a grid of 30,400 model SEDs and use it to determine the best-fit model parameters for each protostar. We argue that far-IR data are essential for accurate constraints on protostellar envelope properties. We find that most protostars, and in particular the flat-spectrum sources, are well fit. The median envelope density and median inclination angle decrease from Class 0 to Class I to flat-spectrum protostars, despite the broad range in best-fit parameters in each of the three categories. We also discuss degeneracies in our model parameters. Our results confirm that the different protostellar classes generally correspond to an evolutionary sequence with a decreasing envelope infall rate, but the inclination angle also plays a role in the appearance, and thus interpretation, of the SEDs.

  7. Far-infrared photometry of OJ 287 with the Herschel Space Observatory

    Science.gov (United States)

    Kidger, Mark; Zola, Staszek; Valtonen, Mauri; Lähteenmäki, Anne; Järvelä, Emilia; Tornikoski, Merja; Tammi, Joni; Liakos, Alexis; Poyner, Gary

    2018-03-01

    Context. The blazar OJ 287 has shown a ≈12 year quasi-periodicity over more than a century, in addition to the common properties of violent variability in all frequency ranges. It is the strongest known candidate to have a binary singularity in its central engine. Aim. We aim to better understand the different emission components by searching for correlated variability in the flux over four decades of frequency measurements. Methods: We combined data at frequencies from the millimetric to the visible to characterise the multifrequency light curve in April and May 2010. This includes the only photometric observations of OJ 287 made with the Herschel Space Observatory: five epochs of data obtained over 33 days at 250, 350, and 500 μm with Herschel-SPIRE. Results: Although we find that the variability at 37 GHz on timescales of a few weeks correlates with the visible to near-IR spectral energy distribution, there is a small degree of reddening in the continuum at lower flux levels that is revealed by the decreasing rate of decline in the light curve at lower frequencies. However, we see no clear evidence that a rapid flare detected in the light curve during our monitoring in the visible to near-IR light curve is seen either in the Herschel data or at 37 GHz, suggesting a low-frequency cut-off in the spectrum of such flares. Conclusions.We see only marginal evidence of variability in the observations with Herschel over a month, although this may be principally due to the poor sampling. The spectral energy distribution between 37 GHz and the visible can be characterised by two components of approximately constant spectral index: a visible to far-IR component of spectral index α = -0.95, and a far-IR to millimetric spectral index of α = -0.43. There is no evidence of an excess of emission that would be consistent with the 60 μmdust bump found in many active galactic nuclei. Herschel is an ESA space observatory with science instruments provided by European

  8. Far-infrared observations of M17: The interaction of an H II region with a molecular cloud

    International Nuclear Information System (INIS)

    Gatley, I.; Becklin, E.E.; Sellgren, K.; Werner, M.W.

    1979-01-01

    The central 15' of the M17 H II region--molecular cloud complex has been mapped with 1' resolution simultaneously at 30, 50, and 100 μm. The data suggest that the bulk of the luminosity radiated in the far-infrared is supplied by the exciting stars of the H II region; the far-infrared radiation is thermal emission from dust grains located chiefly outside the ionized gas. Large-scale systematic gradients in both the temperature and the column density of the dust are seen across the source. The appearance of the source in the far-infrared reflects the markedly nonuniform distribution of matter around the exciting stars; the H II region is bounded by the molecular cloud to the southwest. The core of the molecular cloud is heated primarily by infrared radiation from dust within and adjacent to the H II region; no evidence is seen for substantial luminosity sources embedded within the molecular cloud

  9. The Far-Infrared Emission Line and Continuum Spectrum of the Seyfert Galaxy NGC 1068

    Science.gov (United States)

    Spinoglio, Luigi; Smith, Howard A.; Gonzalez-Alfonso, Eduardo; Fisher, Jacqueline

    2005-01-01

    We report on the analysis of the first complete far-infrared spectrum (43-197 microns) of the Seyfert 2 galaxy NGC 1068 as observed with the Long Wavelength Spectrometer (LWS) onboard the Infrared Space Observatory (ISO). In addition to the 7 expected ionic fine structure emission lines, the OH rotational lines at 79, 119 and 163 microns were all detected in emission, which is unique among galaxies with full LWS spectra, where the 119 micron line, where detected, is always in absorption. The observed line intensities were modelled together with IS0 Short Wavelength Spectrometer (SWS) and optical and ultraviolet line intensities from the literature, considering two independent emission components: the AGN component and the starburst component in the circumnuclear ring of approximately 3kpc in size. Using the UV to mid-IR emission line spectrum to constrain the nuclear ionizing continuum, we have confirmed previous results: a canonical power-law ionizing spectrum is a poorer fit than one with a deep absorption trough, while the presence of a big blue bump is ruled out. Based on the instantaneous starburst age of 5 Myr constrained by the Br gamma equivalent width in the starburst ring, and starburst synthesis models of the mid- and far-infrared fine-structure line emission, a low ionization parameter (U=10(exp -3.5)) and low densities (n=100 cm (exp -3)) are derived. Combining the AGN and starburst components, we succeed in modeling the overall UV to far-IR atomic spectrum of SGC 1068, reproducing the line fluxes to within a factor 2.0 on average with a standard deviation of 1.4. The OH 119 micron emission indicates that the line is collisionally excited, and arises in a warm and dense region. The OH emission has been modeled using spherically symmetric, non-local, non-LTE radiative transfer models. The models indicate that the bulk of the emission arises from the nuclear region, although some extended contribution from the starburst is not ruled out. The OH abundance

  10. Third harmonic generation of high power far infrared radiation in semiconductors

    International Nuclear Information System (INIS)

    Urban, M.

    1996-04-01

    In this work we investigated the third harmonic generation of high power infrared radiation in doped semiconductors with emphasis on the conversion efficiency. The third harmonic generation effect is based on the nonlinear response of the conduction band electrons in the semiconductor with respect to the electric field of the incident electromagnetic wave. Because this work is directed towards a proposed application in fusion plasma diagnostics, the experimental requirements for the radiation source at the fundamental frequency are roughly given as follows: a wavelength of the radiation at the fundamental frequency in the order of 1 mm and an incident power greater than 1 MW. The most important experiments of this work were performed using the high power far infrared laser of the CRPP. With this laser a new laser line was discovered, which fits exactly the source specifications given above: the wavelength is 676 μm and the maximum power is up to 2 MW. Additional experiments were carried out using a 496 μm laser and a 140 GHz (2.1 mm) gyrotron. The main experimental progress with respect to previous work in this field is, in addition to the use of a very high power laser, the possibility of an absolute calibration of the detectors for the far infrared radiation and the availability of a new type of detector with a very fast response. This detector made it possible to measure the power at the fundamental as well as the third harmonic frequency with full temporal resolution of the fluctuations during the laser pulse. Therefore the power dependence of the third harmonic generation efficiency could be measured directly. The materials investigated were InSb as an example of a narrow gap semiconductor and Si as standard material. The main results are: narrow gap semiconductors indeed have a highly nonlinear electronic response, but the narrow band gap leads at the same time to a low power threshold for internal breakdown, which is due to impact ionization. (author) figs

  11. HAWC+/SOFIA observations of Rho Oph A: far-infrared polarization spectrum

    Science.gov (United States)

    Santos, Fabio; Dowell, Charles D.; Houde, Martin; Looney, Leslie; Lopez-Rodriguez, Enrique; Novak, Giles; Ward-Thompson, Derek; HAWC+ Science Team

    2018-01-01

    In this work, we present preliminary results from the HAWC+ far-infrared polarimeter that operates on the SOFIA airborne observatory. The densest portions of the Rho Ophiuchi molecular complex, known as Rho Oph A, have been mapped using HAWC+ bands C (89 microns) and D (155 microns). Rho Oph A is a well known nearby star forming region. At the target's distance of approximately 130 pc, our observations provide excellent spatial resolution (~5 mpc in band C).The magnetic field map suggests a compressed and distorted field morphology around Oph S1, a massive B3 star that is the main heat source of Rho Oph A. We compute the ratio p(D)/p(C), where p(C) and p(D) are the polarization degree maps at bands C and D, respectively. This ratio estimates the slope of the polarization spectrum in the far-infrared. Although the slope is predicted to be positive by dust grain models, previous observations of other molecular clouds have revealed that negative slopes are common. In Rho Oph A, we find that there is a smooth gradient of p(D)/p(C) across the mapped field. The change in p(D)/p(C) is well correlated with the integrated NH3 (1,1) emission. A positive slope dominates the lower density and well illuminated portions of the cloud, whereas a transition to a negative slope is observed at the denser and less evenly illuminated cloud core.We interpret the positive to negative slope transition as being consistent with the radiative torques (RATs) grain alignment theory. For the sight lines of higher column density, polarized emission from the warmer outer cloud layers is added to emission from the colder inner well-shielded layers lying along the same line-of-sight. Given that the outer layers receive more radiation from Oph S1, their grain alignment efficiency is expected to be higher according to RATs. The combination of warmer, well aligned grains with cooler, poorly aligned grains is what causes the negative slope. This effect is not present in the sight lines of lower column

  12. Safari: instrument design of the far-infrared imaging spectrometer for spica

    Science.gov (United States)

    Jellema, W.; Pastor, C.; Naylor, D.; Jackson, B.; Sibthorpe, B.; Roelfsema, P.

    2017-11-01

    The next great leap forward in space-based far-infrared astronomy will be made by the Japanese-led SPICA mission, which is anticipated to be launched late 2020's as the next large astrophysics mission of JAXA, in partnership with ESA and with key European contributions. Filling in the gap between JWST and ALMA, the SPICA mission will study the evolution of galaxies, stars and planetary systems. SPICA will utilize a deeply cooled 3m-class telescope, provided by European industry, to realize zodiacal background limited performance, high spatial resolution and large collecting area. Making full advantage of the deeply cooled telescope (architecture. We will describe the reference design of the SAFARI focal- plane unit, the implementation of the various optical instrument functions designed around the central large-stroke FTS system, the photometric band definition and out-of-band filtering by quasioptical elements, the control of straylight, diffraction and thermal emission in the long-wavelength limit, and how we interface to the large-format FPA arrays at one end and the SPICA telescope assembly at the other end. We will briefly discuss the key performance drivers with special emphasis on the optical techniques adopted to overcome issues related to very low background operation of SAFARI. A summary and discussion of the expected instrument performance and an overview of the astronomical capabilities finally conclude the paper.

  13. Mission Concept for the Single Aperture Far-Infrared (SAFIR) Observatory

    Science.gov (United States)

    Benford, Dominic J.; Amato, Michael J.; Mather, John C.; Moseley, S. Harvey, Jr.

    2004-01-01

    We have developed a preliminary but comprehensive mission concept for SAFIR, as a 10 m-class far-infrared and submillimeter observatory that would begin development later in this decade to meet the needs outlined above. Its operating temperature ( or approx. 40 microns. This would provide a point source sensitivity improvement of several orders of magnitude over that of the Spitzer Space Telescope (previously SIRTF) or the Herschel Space Observatory. Additionally, it would have an angular resolution 12 times finer than that of Spitzer and three times finer than Herschel. This sensitivity and angular resolution are necessary to perform imaging and spectroscopic studies of individual galaxies in the early universe. We have considered many aspects of the SAFIR mission, including the telescope technology (optical design, materials, and packaging), detector needs and technologies, cooling method and required technology developments, attitude and pointing, power systems, launch vehicle, and mission operations. The most challenging requirements for this mission are operating temperature and aperture size of the telescope, and the development of detector arrays. SAFIR can take advantage of much of the technology under development for JWST, but with much less stringent requirements on optical accuracy.

  14. Use of a Far-Infrared Active Warming Device in Guinea Pigs (Cavia porcellus).

    Science.gov (United States)

    Zarndt, Bethany S; Buchta, Jessica N; Garver, Lindsey S; Davidson, Silas A; Rowton, Edgar D; Despain, Kenneth E

    2015-11-01

    Small mammals have difficulty maintaining body temperature under anesthesia. This hypothermia is a potential detriment not only to the health and comfort of the animal but also to the integrity of any treatment given or data gathered during the anesthetic period. Using an external warming device to assist with temperature regulation can mitigate these effects. In this study, we investigated the ability of an advanced warming device that uses far-infrared (FIR) heating and responds to real-time core temperature monitoring to maintain a normothermic core temperature in guinea pigs. Body temperatures were measured during 30 min of ketamine-xylazine general anesthesia with and without application of the heating device. The loss of core body heat from anesthetized guinea pigs under typical (unwarmed) conditions was significant, and this loss was almost completely mitigated by application of the FIR heating pad. The significant difference between the temperatures of the actively warmed guinea pigs as compared with the control group began as early as 14 min after anesthetic administration, leading to a 2.6 °C difference at 30 min. Loss of core body temperature was not correlated with animals' body weight; however, weight influences the efficiency of FIR warming slightly. These study results show that the FIR heating device accurately controls core body temperature in guinea pigs, therefore potentially alleviating the effects of body heat loss on animal physiology.

  15. Application of far-infrared spectroscopy to the structural identification of protein materials.

    Science.gov (United States)

    Han, Yanchen; Ling, Shengjie; Qi, Zeming; Shao, Zhengzhong; Chen, Xin

    2018-05-03

    Although far-infrared (IR) spectroscopy has been shown to be a powerful tool to determine peptide structure and to detect structural transitions in peptides, it has been overlooked in the characterization of proteins. Herein, we used far-IR spectroscopy to monitor the structure of four abundant non-bioactive proteins, namely, soybean protein isolate (SPI), pea protein isolate (PPI) and two types of silk fibroins (SFs), domestic Bombyx mori and wild Antheraea pernyi. The two globular proteins SPI and PPI result in broad and weak far-IR bands (between 50 and 700 cm-1), in agreement with those of some other bioactive globular proteins previously studied (lysozyme, myoglobin, hemoglobin, etc.) that generally only have random amino acid sequences. Interestingly, the two SFs, which are characterized by a structure composed of highly repetitive motifs, show several sharp far-IR characteristic absorption peaks. Moreover, some of these characteristic peaks (such as the peaks at 260 and 428 cm-1 in B. mori, and the peaks at 245 and 448 cm-1 in A. pernyi) are sensitive to conformational changes; hence, they can be directly used to monitor conformational transitions in SFs. Furthermore, since SF absorption bands clearly differ from those of globular proteins and different SFs even show distinct adsorption bands, far-IR spectroscopy can be applied to distinguish and determine the specific SF component within protein blends.

  16. SEASONAL DISAPPEARANCE OF FAR-INFRARED HAZE IN TITAN'S STRATOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Jennings, Donald E.; Anderson, C. M.; Flasar, F. M.; Cottini, V. [Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Samuelson, R. E.; Nixon, C. A.; Kunde, V. G.; Achterberg, R. K. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); De Kok, R. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands); Coustenis, A.; Vinatier, S. [LESIA, Observatoire de Paris-Meudon, 92195 Meudon Cedex (France); Calcutt, S. B., E-mail: donald.e.jennings@nasa.gov [Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom)

    2012-07-20

    A far-infrared emission band attributed to volatile or refractory haze in Titan's stratosphere has been decreasing in intensity since Cassini's arrival in 2004. The 220 cm{sup -1} feature, first seen by the Voyager Infrared Interferometer Spectrometer, has only been found in Titan's winter polar region. The emission peaks at about 140 km altitude near the winter stratospheric temperature minimum. Observations recorded over the period 2004-2012 by the Composite Infrared Spectrometer on Cassini show a decrease in the intensity of this feature by about a factor of four. Possible seasonal causes of this decline are an increase in photolytic destruction of source chemicals at high altitude, a lessening of condensation as solar heating increased, or a weakening of downwelling of vapors. As of early 2012, the 220 cm{sup -1} haze has not yet been detected in the south. The haze composition is unknown, but its decrease is similar to that of HC{sub 3}N gas in Titan's polar stratosphere, pointing to a nitrile origin.

  17. Solid state spectroscopy by using of far-infrared synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nanba, Takao [Kobe Univ. (Japan). Faculty of Science

    1996-07-01

    If the spectroscopic system corresponding to the wavelength region required for experiment is installed, the light source with continuous wavelength is to be obtainable by synchrotron radiation. This report is that of the research on solid state spectroscopy using the ordinary incoherent synchrotron radiation which is obtained from the deflection electromagnet parts of electron storage ring. At present in the world, the facilities which can be utilized in far-infrared spectroscopy region are five, including the UVSOR of Molecular Science Research Institute in Japan. The optical arrangement of the measuring system of the UVSOR is shown. The spectrum distribution of the light passing through the pinholes with different diameter in the place of setting samples was compared in case of the UVSOR and a high pressure mercury lamp, and it was shown that synchrotron radiation has high luminance. The researches on solid state spectroscopy carried out in the above mentioned five facilities are enumerated. In this paper, the high pressure spectroscopic experiment which has been carried out at the UVSOR is reported. The observation of the phase transition of fine particles and the surface phonons of fine particles are described. As fine particle size became smaller, the critical pressure at which phase transition occurred was high. (K.I.)

  18. Micro-Spec: An Ultracompact, High-sensitivity Spectrometer for Far-Infrared and Submillimeter Astronomy

    Science.gov (United States)

    Cataldo, Giuseppe; Hsieh, Wen-Ting; Huang, Wei-Chung; Moseley, S. Harvey; Stevenson, Thomas R.; Wollack, Edward J.

    2014-01-01

    High-performance, integrated spectrometers operating in the far-infrared and submillimeter ranges promise to be powerful tools for the exploration of the epochs of reionization and initial galaxy formation. These devices, using high-efficiency superconducting transmission lines, can achieve the performance of a meter-scale grating spectrometer in an instrument implemented on a 4 inch silicon wafer. Such a device, when combined with a cryogenic telescope in space, provides an enabling capability for studies of the early universe. Here, the optical design process for Micro-Spec (micron-Spec) is presented, with particular attention given to its two-dimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the stigmatization and minimization of the light path function in this bounded region, which results in an optimized geometrical configuration. A point design with an efficiency of (is) approximately 90% has been developed for initial demonstration and can serve as the basis for future instruments. Design variations on this implementation are also discussed, which can lead to lower efficiencies due to diffractive losses in the multimode region.

  19. Influence of Water Activated by Far infrared Porous Ceramics on Nitrogen Absorption in the Pig Feed.

    Science.gov (United States)

    Meng, Junping; Liu, Jie; Liang, Jinsheng; Zhang, Hongchen; Ding, Yan

    2016-04-01

    Under modern and, intensive feeding livestock and poultry density has increased, and brought a deterioration of the farm environment. The livestock and their excrement generate harmful gases such as ammonia, etc. which restricted the sustainable development and improvement of production efficiency of animal husbandry. In this paper, a new kind of far infrared porous ceramics was prepared to activate, the animal drinking water. The activated water and common water were then supplied to pigs, and the fresh pig feces of experimental group and:control group were collected on a regular basis. The residual protein content in feces was tested by Kjeldahl nitrogen method to study the influence law of the porous ceramics on absorbing nitrogen element in animal feces. The results showed that compared with the control group, the protein content in the experimental group decreased on average by 39.2%. The activated drinking water was conducive to the absorption of nitrogen in pig feed. The clusters of water molecules became smaller under the action of the porous ceramics. Hence, they were easy to pass through the water protein channel on the cell membrane for speeding up the metabolism.

  20. Recognizing pedestrian's unsafe behaviors in far-infrared imagery at night

    Science.gov (United States)

    Lee, Eun Ju; Ko, Byoung Chul; Nam, Jae-Yeal

    2016-05-01

    Pedestrian behavior recognition is important work for early accident prevention in advanced driver assistance system (ADAS). In particular, because most pedestrian-vehicle crashes are occurred from late of night to early of dawn, our study focus on recognizing unsafe behavior of pedestrians using thermal image captured from moving vehicle at night. For recognizing unsafe behavior, this study uses convolutional neural network (CNN) which shows high quality of recognition performance. However, because traditional CNN requires the very expensive training time and memory, we design the light CNN consisted of two convolutional layers and two subsampling layers for real-time processing of vehicle applications. In addition, we combine light CNN with boosted random forest (Boosted RF) classifier so that the output of CNN is not fully connected with the classifier but randomly connected with Boosted random forest. We named this CNN as randomly connected CNN (RC-CNN). The proposed method was successfully applied to the pedestrian unsafe behavior (PUB) dataset captured from far-infrared camera at night and its behavior recognition accuracy is confirmed to be higher than that of some algorithms related to CNNs, with a shorter processing time.

  1. Atrazine Molecular Imprinted Polymers: Comparative Analysis by Far-Infrared and Ultraviolet Induced Polymerization

    Directory of Open Access Journals (Sweden)

    Jun Chen

    2014-01-01

    Full Text Available Atrazine molecular imprinted polymers (MIPs were comparatively synthesized using identical polymer formulation by far-infrared (FIR radiation and ultraviolet (UV-induced polymerization, respectively. Equilibrium binding experiments were carried out with the prepared MIPs; the results showed that MIPuv possessed specific binding to atrazine compared with their MIPFIR radiation counterparts. Scatchard plot’s of both MIPs indicated that the affinities of the binding sites in MIPs are heterogeneous and can be approximated by two dissociation-constants corresponding to the high- and low-affinity binding sites. Moreover, several common pesticides including atrazine, cyromazine, metamitron, simazine, ametryn, terbutryn were tested to determine their specificity, similar imprinting factor (IF and different selectivity index (SI for both MIPs. Physical characterization of the polymers revealed that the different polymerization methods led to slight differences in polymer structures and performance by scanning electron microscope (SEM, Fourier transform infrared absorption (FT-IR, and mercury analyzer (MA. Finally, both MIPs were used as selective sorbents for solid phase extraction (SPE of atrazine from lake water, followed by high performance liquid chromatography (HPLC analysis. Compared with commercial C18 SPE sorbent (86.4%–94.8%, higher recoveries of atrazine in spiked lake water were obtained in the range of 90.1%–97.1% and 94.4%–101.9%, for both MIPs, respectively.

  2. Far-infrared pedestrian detection for advanced driver assistance systems using scene context

    Science.gov (United States)

    Wang, Guohua; Liu, Qiong; Wu, Qingyao

    2016-04-01

    Pedestrian detection is one of the most critical but challenging components in advanced driver assistance systems. Far-infrared (FIR) images are well-suited for pedestrian detection even in a dark environment. However, most current detection approaches just focus on pedestrian patterns themselves, where robust and real-time detection cannot be well achieved. We propose a fast FIR pedestrian detection approach, called MAP-HOGLBP-T, to explicitly exploit the scene context for the driver assistance system. In MAP-HOGLBP-T, three algorithms are developed to exploit the scene contextual information from roads, vehicles, and background objects of high homogeneity, and we employ the Bayesian approach to build a classifier learner which respects the scene contextual information. We also develop a multiframe approval scheme to enhance the detection performance based on spatiotemporal continuity of pedestrians. Our empirical study on real-world datasets has demonstrated the efficiency and effectiveness of the proposed method. The performance is shown to be better than that of state-of-the-art low-level feature-based approaches.

  3. Properties in the middle and far infrared radiation of spiral and irregular galaxies

    International Nuclear Information System (INIS)

    Contursi, Alessandra

    1998-01-01

    In the first part of this research thesis, the author reports the study in the middle infrared of H II regions belonging to Magellanic clouds. For this purpose, he presents different aspects of infrared emission by the interstellar medium: origin and evolution of interstellar grains, dust studied by astrophysical observations, dust models, infrared observations made by COBE and IRAS satellites, exploitation of the ISO satellite. He also presents the Small and Large Magellanic clouds, and reports the study of the H II N4 region of the large one, imagery and spectroscopy of the H II N66 region of the small one, and the study of silicate emission in the central region of N66. The second part reports the study of cluster normal spiral galaxies in the middle and far infrared. For this purpose, the author discusses the colours in the middle infrared of Virgo's and Coma's galaxies, discusses the properties in the infrared of spiral galaxies (Coma and A1367), based on observations made by ISO [fr

  4. High resolution far-infrared observations of the evolved H II region M16

    International Nuclear Information System (INIS)

    McBreen, B.; Fazio, G.G.; Jaffe, D.T.

    1982-01-01

    M16 is an evolved, extremely density bounded H II region, which now consists only of a series of ionization fronts at molecular cloud boundaries. The source of ionization is the OB star cluster (NGC 6611) which is about 5 x 10 6 years old. We used the CFA/UA 102 cm balloon-borne telescope to map this region and detected three far-infrared (far-IR) sources embedded in an extended ridge of emission. Source I is an unresolved far-IR source embedded in a molecular cloud near a sharp ionization front. An H 2 O maser is associated with this source, but no radio continuum emission has been observed. The other two far-IR sources (II and III) are associated with ionized gas-molecular cloud interfaces, with the far-IR radiation arising from dust at the boundary heated by the OB cluster. Source II is located at the southern prominent neutral intrusion with its associated bright rims and dark ''elephant trunk'' globules that delineate the current progress of the ionization front into the neutral material, and Source III arises at the interface of the northern molecular cloud fragment

  5. Far-Infrared Radiation Thermotherapy Improves Tissue Fibrosis in Chronic Extremity Lymphedema.

    Science.gov (United States)

    Li, Ke; Zhang, Zheng; Liu, Ning Fei; Sadigh, Parviz; Evans, Verity Joyce; Zhou, Huihong; Gao, Weiqing; Zhang, Yi Xin

    2017-09-29

    Fibrosis can enhance the exacerbation of lymphedema, which becomes obvious in late stage II-III lymphedema. However, whether far-infrared radiation thermotherapy (FIRT) can cure lymphedema fibrosis is still lack of research. This research was to investigate the therapeutic effect of FIRT on tissue fibrosis in the treatment of Late stage II-III lymphedema. Patients accepted only FIRT for a total of 20 sessions. The treatment session duration was 2 hours, and a stable machine temperature of 42°C was maintained throughout treatments. Clinical evaluation and laboratory evaluation were conducted before and after FIRT. Clinical outcome measures included circumference of affected extremity, skin elasticity, ultrasound, patients' subjective assessment, and quality of life (QOL). Laboratory outcome measures included serum and local lymphedema tissue fluid concentrations of fibrosis associated cytokines, tissue growth factor beta-1 (TGF-β1), interleukin (IL)-1β, IL-4, IL-18, and caspase-1. Between 2015 and 2016, clinical evaluation of 64 patients with late stage II-III lymphedema was conducted. From this group, 12 cases (18.75%) underwent simultaneous laboratory evaluation. Circumferences of affected extremities improved significantly following treatment (p pain, discomfort, and numbness (p effective treatment for lymphedema tissue fibrosis; it reduces the concentration of fibrosis cytokines in local lymphedema tissues. Consequently, this treatment can reduce the density of fibrosed tissue in the affected extremity, increase skin elasticity, significantly improve clinical symptoms, and improve QOL of patients.

  6. H-ATLAS: THE COSMIC ABUNDANCE OF DUST FROM THE FAR-INFRARED BACKGROUND POWER SPECTRUM

    Energy Technology Data Exchange (ETDEWEB)

    Thacker, Cameron; Cooray, Asantha; Smidt, Joseph; De Bernardis, Francesco; Mitchell-Wynne, K. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Amblard, A. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Auld, R.; Eales, S.; Pascale, E. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff, CF24 3AA (United Kingdom); Baes, M.; Michalowski, M. J. [Sterrenkundig Observatorium, Universiteit Gent, KrijgslAAn 281 S9, B-9000 Gent (Belgium); Clements, D. L.; Dariush, A.; Hopwood, R. [Physics Department, Imperial College London, South Kensington campus, London, SW7 2AZ (United Kingdom); De Zotti, G. [INAF, Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, I-35122 Padova (Italy); Dunne, L.; Maddox, S. [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Hoyos, C. [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Ibar, E. [UK Astronomy Technology Centre, The Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom); Jarvis, M. [Astrophysics, Department of Physics, Keble Road, Oxford, OX1 3RH (United Kingdom); and others

    2013-05-01

    We present a measurement of the angular power spectrum of the cosmic far-infrared background (CFIRB) anisotropies in one of the extragalactic fields of the Herschel Astrophysical Terahertz Large Area Survey at 250, 350, and 500 {mu}m bands. Consistent with recent measurements of the CFIRB power spectrum in Herschel-SPIRE maps, we confirm the existence of a clear one-halo term of galaxy clustering on arcminute angular scales with large-scale two-halo term of clustering at 30 arcmin to angular scales of a few degrees. The power spectrum at the largest angular scales, especially at 250 {mu}m, is contaminated by the Galactic cirrus. The angular power spectrum is modeled using a conditional luminosity function approach to describe the spatial distribution of unresolved galaxies that make up the bulk of the CFIRB. Integrating over the dusty galaxy population responsible for the background anisotropies, we find that the cosmic abundance of dust, relative to the critical density, to be between {Omega}{sub dust} = 10{sup -6} and 8 Multiplication-Sign 10{sup -6} in the redshift range z {approx} 0-3. This dust abundance is consistent with estimates of the dust content in the universe using quasar reddening and magnification measurements in the Sloan Digital Sky Survey.

  7. Modelling the cosmic spectral energy distribution and extragalactic background light over all time

    Science.gov (United States)

    Andrews, S. K.; Driver, S. P.; Davies, L. J. M.; Lagos, C. d. P.; Robotham, A. S. G.

    2018-02-01

    We present a phenomological model of the cosmic spectral energy distribution (CSED) and the integrated galactic light (IGL) over all cosmic time. This model, based on an earlier model by Driver et al., attributes the cosmic star formation history (CSFH) to two processes - first, chaotic clump accretion and major mergers, resulting in the early-time formation of bulges and secondly, cold gas accretion, resulting in late-time disc formation. Under the assumption of a Universal Chabrier initial mass function, we combine the Bruzual & Charlot stellar libraries, the Charlot & Fall dust attenuation prescription and template spectra for emission by dust and active galactic nuclei to predict the CSED - pre- and post-dust attenuation - and the IGL throughout cosmic time. The phenomological model, as constructed, adopts a number of basic axioms and empirical results and has minimal free parameters. We compare the model output, as well as predictions from the semi-analytic model GALFORM to recent estimates of the CSED out to z = 1. By construction, our empirical model reproduces the full energy output of the Universe from the ultraviolet to the far-infrared extremely well. We use the model to derive predictions of the stellar and dust mass densities, again finding good agreement. We find that GALFORM predicts the CSED for z < 0.3 in good agreement with the observations. This agreement becomes increasingly poor towards z = 1, when the model CSED is ˜50 per cent fainter. The latter is consistent with the model underpredicting the CSFH. As a consequence, GALFORM predicts a ˜30 per cent fainter IGL.

  8. Far-Infrared Emission Characteristics and Wear Comfort Property of ZrC-Imbedded Heat Storage Knitted Fabrics for Emotional Garments

    Directory of Open Access Journals (Sweden)

    Kim Hyun Ah

    2017-06-01

    Full Text Available This study examined the far-infrared emission characteristics and wear comfort properties of ZrC-imbedded heat storage knitted fabrics. For this purpose, ZrC-imbedded, heat storage PET (polyethylene terephthalate was spun from high-viscosity PET with imbedded ZrC powder on the core part and low-viscosity PET on the sheath part using a conjugated spinning method. ZrC-imbedded PET knitted fabric was also prepared and its physical properties were measured and compared with those of regular PET knitted fabric. In addition, ingredient analysis and the far-infrared emission characteristics of the ZrC-imbedded knitted fabrics were analyzed by energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The thermal properties, moisture absorption, and drying properties of the ZrC-imbedded PET knitted fabric were measured and compared with those of the regular PET knitted fabric. The mechanical properties using the FAST (fabric assurance by simple testing system and the dye affinity of the ZrC-imbedded knitted fabric were also measured and compared with those of regular PET knitted fabric.

  9. A kilo-pixel imaging system for future space based far-infrared observatories using microwave kinetic inductance detectors

    NARCIS (Netherlands)

    Baselmans, J.J.A.; Bueno, J.; Yates, Stephen J.C.; Yurduseven, O.; Llombart Juan, N.; Karatsu, K.; Baryshev, A. M.; Ferrarini, L; Endo, A.; Thoen, D.J.; de Visser, P.J.; Janssen, R.M.J.; Murugesan, V.; Driessen, E.F.C.; Coiffard, G.; Martin-Pintado, J.; Hargrave, P.; Griffin, M.

    2017-01-01

    Aims. Future astrophysics and cosmic microwave background space missions operating in the far-infrared to millimetre part of the spectrum will require very large arrays of ultra-sensitive detectors in combination with high multiplexing factors and efficient low-noise and low-power readout systems.

  10. A kilo-pixel imaging system for future space based far-infrared observatories using microwave kinetic inductance detectors

    NARCIS (Netherlands)

    Baselmans, J. J. A.; Bueno, J.; Yates, S. J. C.; Yurduseven, O.; Llombart, N.; Karatsu, K.; Baryshev, A. M.; Ferrari, L.; Endo, A.; Thoen, D. J.; de Visser, P. J.; Janssen, R. M. J.; Murugesan, V.; Driessen, E. F. C.; Coiffard, G.; Martin-Pintado, J.; Hargrave, P.; Griffin, M.

    Aims: Future astrophysics and cosmic microwave background space missions operating in the far-infrared to millimetre part of the spectrum will require very large arrays of ultra-sensitive detectors in combination with high multiplexing factors and efficient low-noise and low-power readout systems.

  11. Possibility of observation of polaron normal modes at the far-infrared spectrum of acetanilide and related organics

    Science.gov (United States)

    Kalosakas, G.; Aubry, S.; Tsironis, G. P.

    1998-10-01

    We use a stationary and normal mode analysis of the semiclassical Holstein model in order to connect the low-frequency linear polaron modes to low-lying far-infrared lines of the acetanilide spectrum and through parameter fitting we comment on the validity of the polaron results in this system.

  12. Development of transition edge superconducting bolometers for the SAFARI Far-Infrared spectrometer on the SPICA space-borne telescope

    NARCIS (Netherlands)

    Mauskopf, P.; Morozov, D.; Glowacka, D.; Goldie, D.; Withington, S.; Bruijn, M.; De Korte, P.; Hoevers, H.; Ridder, M.; Van der Kuur, J.; Gao, J.R.

    2008-01-01

    We describe the optimization of transition edge superconducting (TES) detectors for use in a far-infrared (FIR) Fourier transform spectrometer (FTS) mounted on a cryogenically cooled space-borne telescope (e.g. SPICA). The required noise equivalent power (NEP) of the detectors is approximately 10?19

  13. Infrared Space Observatory Observations of Far-Infrared Rotational Emission Lines of Water Vapor toward the Supergiant Star VY Canis Majoris

    Science.gov (United States)

    Neufeld, David A.; Feuchtgruber, Helmut; Harwit, Martin; Melnick, Gary J.

    1999-06-01

    We report the detection of numerous far-infrared emission lines of water vapor toward the supergiant star VY Canis Majoris. A 29.5-45 μm grating scan of VY CMa, obtained using the Short-Wavelength Spectrometer (SWS) of the Infrared Space Observatory at a spectral resolving power λ/Δλ of ~2000, reveals at least 41 spectral features due to water vapor that together radiate a total luminosity of ~25 Lsolar. In addition to pure rotational transitions within the ground vibrational state, these features include rotational transitions within the (010) excited vibrational state. The spectrum also shows the 2Π1/2(J=5/2)VY CMa were carried out in the instrument's Fabry-Perot mode for three water transitions: the 725-616 line at 29.8367 μm, the 441-312 line at 31.7721 μm, and the 432-303 line at 40.6909 μm. The higher spectral resolving power λ/Δλ of approximately 30,000 thereby obtained permits the line profiles to be resolved spectrally for the first time and reveals the ``P Cygni'' profiles that are characteristic of emission from an outflowing envelope. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands, and the UK) with the participation of ISAS and NASA.

  14. Thermal imaging method to visualize a hidden painting thermally excited by far infrared radiations

    Science.gov (United States)

    Davin, T.; Wang, X.; Chabane, A.; Pawelko, R.; Guida, G.; Serio, B.; Hervé, P.

    2015-06-01

    The diagnosis of hidden painting is a major issue for cultural heritage. In this paper, a non-destructive active infrared thermographic technique was considered to reveal paintings covered by a lime layer. An extended infrared spectral range radiation was used as the excitation source. The external long wave infrared energy source delivered to the surface is then propagated through the material until it encounters a painting zone. Due to several thermal effects, the sample surface then presents non-uniformity patterns. Using a high sensitive infrared camera, the presence of covered pigments can thus be highlighted by the analysis of the non-stationary phenomena. Reconstituted thermal contrast images of mural samples covered by a lime layer are shown.

  15. Far-infrared reflection-absorption spectroscopy of amorphous and polycrystalline gallium arsenide films

    International Nuclear Information System (INIS)

    Gregory, J.R.

    1992-01-01

    We have reported far-infrared reflection absorption spectra (30-320CM -1 ) at 30 and 310K for nine films of non-stoichiometric GaAs. The FIRRAS measurements were performed using the grazing incidence FIR double-modulation spectroscopy technique first described by DaCosta and Coleman. The films were fabricated by molecular beam deposition on metallized substrates for two As/Ga molecular beam flux ratios. The films were characterized by depth profilometry, IRAS, XRD, and x-ray microprobe analysis. Film thicknesses ranged from 800 to 5800 angstrom and compositions were 45-50% As for a MB flux ratio of 0.29 and 60-70% As for a ratio of 1.12. FIRRAS measurements were made and characterizations performed for as-deposited films and for 5 hour anneals at 473, 573, 673 and 723 degrees C. Vibrational spectra of the crystallized films were interpreted in terms of the exact reflectivity of a thin dielectric film on a conducting substrate, using a classical Lorentzian dielectric function for the response of the film. Resonances appearing in the open-quote forbidden close-quote region between the TO and LO frequencies were modelled with an effective medium approximation and are interpreted as arising from small-scale surface roughness. The behavior of the amorphous film spectra were examined within two models. The effective force constant model describes the variation of the reflection-absorption maxima with measured crystallite size in terms of the effective vibration frequency of 1-D atomic chains having force constants distributed according to the parameters of the crystalline-to-amorphous relaxation length and the crystalline to amorphous force constant ratio. The dielectric function continuum model uses the relaxation of the crystal momentum selection rule to calculate the reflection-absorption spectrum based on a dielectric function in which the oscillator strength is the normalized product of a constant dipole strength and the smoothed vibrational density of states

  16. Far infrared promotes wound healing through activation of Notch1 signaling.

    Science.gov (United States)

    Hsu, Yung-Ho; Lin, Yuan-Feng; Chen, Cheng-Hsien; Chiu, Yu-Jhe; Chiu, Hui-Wen

    2017-11-01

    The Notch signaling pathway is critically involved in cell proliferation, differentiation, development, and homeostasis. Far infrared (FIR) has an effect that promotes wound healing. However, the underlying molecular mechanisms are unclear. In the present study, we employed in vivo and HaCaT (a human skin keratinocyte cell line) models to elucidate the role of Notch1 signaling in FIR-promoted wound healing. We found that FIR enhanced keratinocyte migration and proliferation. FIR induced the Notch1 signaling pathway in HaCaT cells and in a microarray dataset from the Gene Expression Omnibus database. We next determined the mRNA levels of NOTCH1 in paired normal and wound skin tissues derived from clinical patients using the microarray dataset and Ingenuity Pathway Analysis software. The result indicated that the Notch1/Twist1 axis plays important roles in wound healing and tissue repair. In addition, inhibiting Notch1 signaling decreased the FIR-enhanced proliferation and migration. In a full-thickness wound model in rats, the wounds healed more rapidly and the scar size was smaller in the FIR group than in the light group. Moreover, FIR could increase Notch1 and Delta1 in skin tissues. The activation of Notch1 signaling may be considered as a possible mechanism for the promoting effect of FIR on wound healing. FIR stimulates keratinocyte migration and proliferation. Notch1 in keratinocytes has an essential role in FIR-induced migration and proliferation. NOTCH1 promotes TWIST1-mediated gene expression to assist wound healing. FIR might promote skin wound healing in a rat model. FIR stimulates keratinocyte migration and proliferation. Notch1 in keratinocytes has an essential role in FIR-induced migration and proliferation. NOTCH1 promotes TWIST1-mediated gene expression to assist wound healing. FIR might promote skin wound healing in a rat model.

  17. Poloidal magnetic field profile measurements on the microwave tokamak experiment using far-infrared polarimetry

    International Nuclear Information System (INIS)

    Rice, B.W.

    1992-09-01

    The measurement of plasma poloidal magnetic field (B) profiles in tokamaks with good temporal and spatial resolution has proven to be a difficult but important measurement. A large range of toroidal confinement phenomena is expected to depend sensitively on the radial variation of B including the tearing instability, sawtooth oscillations, disruptions, and transport. Experimental confirmation of theoretical models describing these phenomena has been hampered by the lack of detailed B measurements. A fifteen chord far-infrared (FIR) polarimeter has been developed to measure B in the Microwave Tokamak, Experiment (MTX). Polarimetry utilizes the well known Faraday rotation effect, which causes a rotation of the polarization of an FIR beam propagating in the poloidal plane. The rotation angle is proportional to the component of B parallel to the beam. A new technique for determining the Faraday rotation angle is introduced, based on phase measurements of a rotating polarization ellipse. This instrument has been used successfully to measure B profiles for a wide range of experiments on MTX. For ohmic discharges, measurements of the safety factor on axis give q 0 ∼ 0.75 during sawteeth and q 0 > 1 without sawteeth. Large perturbations to the polarimeter signals correlated with the sawtooth crash are observed during some discharges. Measurements in discharges with electron cyclotron heating (ECH) show a transition from a hollow to peaked J profile that is triggered by the ECH pulse. Current-ramp experiments were done to perturb the J profile from the nominal Spitzer conductivity profile. Profiles for initial current ramps and ramps starting from a stable equilibrium have been measured and are compared with a cylindrical diffusion model. Finally, the tearing mode stability equation is solved using measured J profiles. Stability predictions are in good agreement with the existence of oscillations observed on the magnetic loops

  18. Use of COTS uncooled microbolometers for the observation of solar eruptions in far infrared

    Science.gov (United States)

    Le Ruyet, B.; Bernardi, P.; Sémery, A.

    2017-11-01

    The Small Explorer for Solar Eruptions (SMESE) mission is a French-Chinese satellite dedicated to the combined study of coronal mass ejections and flares. It should operate by the beginning of 2013. The spacecraft is based on a generic MYRIADE platform developed by CNES. Its payload consists of a Lyman α imager and a Lyman α chronograph (LYOT), a far infrared telescope (DESIR) and a hard X and γ ray spectrometer (HEBS). Its Sun-synchronous orbit will allow for continuous observations. LESIA (Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique, in Paris-Meudon Observatory) is in charge of DESIR instrument. DESIR (Detection of Eruptive Solar InfraRed emission) is an imaging photometer observing the sun in two bandwidths: [25; 45μm] and [80; 130μm]. The detector is a commercially available, uncooled microbolometer focal plane array (UL 02 05 1, from ULIS) designed for thermographic imaging in the 8-14 μm wavelength range. The 160x120 pixels are based on amorphous silicon, with dimensions 35x35 μm2. The performances in terms of noise and dynamics given by the manufacturer associated with simulations of a perfect quarter-wave cavity to predict the microbolometer absorption, make possible the use of such a detector to fulfil the DESIR detection specifications in the two FIR bandwidths. During the A Phase, tests have been carried out in our laboratory to validate the feasibility of the project. In this work, we present the first results obtained on the microbolometer performances in the FIR domain.

  19. A novel, highly efficient cavity backshort design for far-infrared TES detectors

    Science.gov (United States)

    Bracken, C.; de Lange, G.; Audley, M. D.; Trappe, N.; Murphy, J. A.; Gradziel, M.; Vreeling, W.-J.; Watson, D.

    2018-03-01

    In this paper we present a new cavity backshort design for TES (transition edge sensor) detectors which will provide increased coupling of the incoming astronomical signal to the detectors. The increased coupling results from the improved geometry of the cavities, where the geometry is a consequence of the proposed chemical etching manufacturing technique. Using a number of modelling techniques, predicted results of the performance of the cavities for frequencies of 4.3-10 THz are presented and compared to more standard cavity designs. Excellent optical efficiency is demonstrated, with improved response flatness across the band. In order to verify the simulated results, a scaled model cavity was built for testing at the lower W-band frequencies (75-100 GHz) with a VNA system. Further testing of the scale model at THz frequencies was carried out using a globar and bolometer via an FTS measurement set-up. The experimental results are presented, and compared to the simulations. Although there is relatively poor comparison between simulation and measurement at some frequencies, the discrepancies are explained by means of higher-mode excitation in the measured cavity which are not accounted for in the single-mode simulations. To verify this assumption, a better behaved cylindrical cavity is simulated and measured, where excellent agreement is demonstrated in those results. It can be concluded that both the simulations and the supporting measurements give confidence that this novel cavity design will indeed provide much-improved optical coupling for TES detectors in the far-infrared/THz band.

  20. HERUS: the far-IR/submm spectral energy distributions of local ULIRGs and photometric atlas

    Science.gov (United States)

    Clements, D. L.; Pearson, C.; Farrah, D.; Greenslade, J.; Bernard-Salas, Jeronimo; González-Alfonso, E.; Afonso, J.; Efstathiou, A.; Rigopoulou, D.; Lebouteiller, V.; Hurley, P. D.; Spoon, H.

    2018-04-01

    We present the Herschel-SPIRE photometric atlas for a complete flux limited sample of 43 local ultraluminous infrared galaxies (ULIRGs), selected at 60 μm by IRAS, as part of the HERschel ULIRG Survey (HERUS). Photometry observations were obtained using the SPIRE instrument at 250, 350, and 500 μm. We describe these observations, present the results, and combine the new observations with data from IRAS to examine the far-infrared spectral energy distributions (SEDs) of these sources. We fit the observed SEDs of HERUS objects with a simple parametrized modified blackbody model, where temperature and emissivity β are free parameters. We compare the fitted values to those of non-ULIRG local galaxies, and find, in agreement with earlier results, that HERUS ULIRGs have warmer dust (median temperature T = 37.9 ± 4.7 K compared to 21.3 ± 3.4 K) but a similar β distribution (median β = 1.7 compared to 1.8) to the Herschel reference sample (HRS, Cortese et al. 2014) galaxies. Dust masses are found to be in the range of 107.5-109 M⊙, significantly higher than that of HRS sources. We compare our results for local ULIRGs with higher redshift samples selected at 250 and 850 μm. These latter sources generally have cooler dust and/or redder 100-to-250 μm colours than our 60 μm-selected ULIRGs. We show that this difference may in part be the result of the sources being selected at different wavelengths rather than being a simple indication of rapid evolution in the properties of the population.

  1. Far infrared (terahertz) spectroscopy of a series of polycyclic aromatic hydrocarbons and application to structure interpretation of asphaltenes and related compounds.

    Science.gov (United States)

    Cataldo, Franco; Angelini, Giancarlo; García-Hernández, D Aníbal; Manchado, Arturo

    2013-07-01

    A series of 33 different polycyclic aromatic hydrocarbons (PAHs) were studied by far infrared spectroscopy (terahertz spectroscopy) in the spectral range comprised between 600 and 50 cm(-1). In addition to common PAHs like naphthalene, anthracene, phenanthrene, fluoranthene, picene, pyrene, benzo[α]pyrene, and perylene, also quite unusual PAHs were studied like tetracene, pentacene, acenaphtene, acenaphtylene, triphenylene, and decacyclene. A series of alkylated naphthalenes and anthracenes were studied as well as methypyrene. Partially or totally hydrogenated PAHs were also object of the present investigation, ranging from tetrahydronaphthalene (tetralin) to decahydronaphthalene (decalin), 9,10-dihydroanthracene, 9,10-dihydrophenanthrene, hexahydropyrene, and dodecahydrotriphenylene. Finally, the large and quite rare PAHs coronene, quaterrylene, hexabenzocoronene, and dicoronylene were studied by far infrared spectroscopy. The resulting reference spectra were used in the interpretation of the chemical structure of asphaltenes (as extracted from a heavy petroleum fraction and from bitumen), the chemical structures of other petroleum fractions known as DAE (distillate aromatic extract) and RAE (residual aromatic extract), and a possible interpretation of components of the chemical structure of anthracite coal. Asphaltenes, heavy petroleum fractions, and coal were proposed as model compounds for the interpretation of the emission spectra of certain proto-planetary nebulae (PPNe) with a good matching in the mid infrared between the band pattern of the PPNe emission spectra and the spectra of these oil fractions or coal. Although this study was finalized in an astrochemical context, it may find application also in the petroleum and coal chemistry. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Measurements of downwelling far-infrared radiance during the RHUBC-II campaign at Cerro Toco, Chile and comparisons with line-by-line radiative transfer calculations

    Science.gov (United States)

    Mast, Jeffrey C.; Mlynczak, Martin G.; Cageao, Richard P.; Kratz, David P.; Latvakoski, Harri; Johnson, David G.; Turner, David D.; Mlawer, Eli J.

    2017-09-01

    Downwelling radiances at the Earth's surface measured by the Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument in an environment with integrated precipitable water (IPW) as low as 0.03 cm are compared with calculated spectra in the far-infrared and mid-infrared. FIRST (a Fourier transform spectrometer) was deployed from August through October 2009 at 5.38 km MSL on Cerro Toco, a mountain in the Atacama Desert of Chile. There FIRST took part in the Radiative Heating in Unexplored Bands Campaign Part 2 (RHUBC-II), the goal of which is the assessment of water vapor spectroscopy. Radiosonde water vapor and temperature vertical profiles are input into the Atmospheric and Environmental Research (AER) Line-by-Line Radiative Transfer Model (LBLRTM) to compute modeled radiances. The LBLRTM minus FIRST residual spectrum is calculated to assess agreement. Uncertainties (1-σ) in both the measured and modeled radiances are also determined. Measured and modeled radiances nearly all agree to within combined (total) uncertainties. Features exceeding uncertainties can be corrected into the combined uncertainty by increasing water vapor and model continuum absorption, however this may not be necessary due to 1-σ uncertainties (68% confidence). Furthermore, the uncertainty in the measurement-model residual is very large and no additional information on the adequacy of current water vapor spectral line or continuum absorption parameters may be derived. Similar future experiments in similarly cold and dry environments will require absolute accuracy of 0.1% of a 273 K blackbody in radiance and water vapor accuracy of ∼3% in the profile layers contributing to downwelling radiance at the surface.

  3. Wave propagation of spectral energy content in a granular chain

    NARCIS (Netherlands)

    Shrivastava, Rohit Kumar; Luding, Stefan

    2017-01-01

    A mechanical wave is propagation of vibration with transfer of energy and momentum. Understanding the spectral energy characteristics of a propagating wave through disordered granular media can assist in understanding the overall properties of wave propagation through inhomogeneous materials like

  4. The impact of clustering and angular resolution on far-infrared and millimeter continuum observations

    Science.gov (United States)

    Béthermin, Matthieu; Wu, Hao-Yi; Lagache, Guilaine; Davidzon, Iary; Ponthieu, Nicolas; Cousin, Morgane; Wang, Lingyu; Doré, Olivier; Daddi, Emanuele; Lapi, Andrea

    2017-11-01

    Follow-up observations at high-angular resolution of bright submillimeter galaxies selected from deep extragalactic surveys have shown that the single-dish sources are comprised of a blend of several galaxies. Consequently, number counts derived from low- and high-angular-resolution observations are in tension. This demonstrates the importance of resolution effects at these wavelengths and the need for realistic simulations to explore them. We built a new 2 deg2 simulation of the extragalactic sky from the far-infrared to the submillimeter. It is based on an updated version of the 2SFM (two star-formation modes) galaxy evolution model. Using global galaxy properties generated by this model, we used an abundance-matching technique to populate a dark-matter lightcone and thus simulate the clustering. We produced maps from this simulation and extracted the sources, and we show that the limited angular resolution of single-dish instruments has a strong impact on (sub)millimeter continuum observations. Taking into account these resolution effects, we are reproducing a large set of observables, as number counts and their evolution with redshift and cosmic infrared background power spectra. Our simulation consistently describes the number counts from single-dish telescopes and interferometers. In particular, at 350 and 500 μm, we find that the number counts measured by Herschel between 5 and 50 mJy are biased towards high values by a factor 2, and that the redshift distributions are biased towards low redshifts. We also show that the clustering has an important impact on the Herschel pixel histogram used to derive number counts from P(D) analysis. We find that the brightest galaxy in the beam of a 500 μm Herschel source contributes on average to only 60% of the Herschel flux density, but that this number will rise to 95% for future millimeter surveys on 30 m-class telescopes (e.g., NIKA2 at IRAM). Finally, we show that the large number density of red Herschel sources

  5. Submillimeter-wave and far-infrared spectroscopy of high-J transitions of the ground and ν2 = 1 states of ammonia.

    Science.gov (United States)

    Yu, Shanshan; Pearson, John C; Drouin, Brian J; Sung, Keeyoon; Pirali, Olivier; Vervloet, Michel; Martin-Drumel, Marie-Aline; Endres, Christian P; Shiraishi, Tetsuro; Kobayashi, Kaori; Matsushima, Fusakazu

    2010-11-07

    Complete and reliable knowledge of the ammonia spectrum is needed to enable the analysis and interpretation of astrophysical and planetary observations. Ammonia has been observed in the interstellar medium up to J=18 and more highly excited transitions are expected to appear in hot exoplanets and brown dwarfs. As a result, there is considerable interest in observing and assigning the high J (rovibrational) spectrum. In this work, numerous spectroscopic techniques were employed to study its high J transitions in the ground and ν(2)=1 states. Measurements were carried out using a frequency multiplied submillimeter spectrometer at Jet Propulsion Laboratory (JPL), a tunable far-infrared spectrometer at University of Toyama, and a high-resolution Bruker IFS 125 Fourier transform spectrometer (FTS) at Synchrotron SOLEIL. Highly excited ammonia was created with a radiofrequency discharge and a dc discharge, which allowed assignments of transitions with J up to 35. One hundred and seventy seven ground state and ν(2)=1 inversion transitions were observed with microwave accuracy in the 0.3-4.7 THz region. Of these, 125 were observed for the first time, including 26 ΔK=3 transitions. Over 2000 far-infrared transitions were assigned to the ground state and ν(2)=1 inversion bands as well as the ν(2) fundamental band. Of these, 1912 were assigned using the FTS data for the first time, including 222 ΔK=3 transitions. The accuracy of these measurements has been estimated to be 0.0003-0.0006 cm(-1). A reduced root mean square error of 0.9 was obtained for a global fit of the ground and ν(2)=1 states, which includes the lines assigned in this work and all previously available microwave, terahertz, far-infrared, and mid-infrared data. The new measurements and predictions reported here will support the analyses of astronomical observations by high-resolution spectroscopy telescopes such as Herschel, SOFIA, and ALMA. The comprehensive experimental rovibrational energy levels

  6. Direction of Wolf-Rayet stars in a very powerful far-infrared galaxy - Direct evidence for a starburst

    International Nuclear Information System (INIS)

    Armus, L.; Heckman, T.M.; Miley, G.K.

    1988-01-01

    Spectra covering the wavelength range 4476-7610 A are presented for the powerful far-infrared galaxy IRAS 01003-2238. The broad emission band centered at a rest wavelength of roughly 4660 A, and other broad weaker features are interpreted, as arising from the combined effect of approximately 100,000 late Wolf-Rayet stars of the WN subtype. This represents perhaps the most direct evidence to date for the presence of a large number of hot massive stars in the nucleus of a very powerful far-infrared galaxy. The high number of Wolf-Rayet stars in relation to the number of O-type stars may be interpreted as arguing against continuous steady state star formation in 01003-2238, in favor of a recent burst of star formation occurring approximately 100 million yrs ago. 24 references

  7. Metallicity and the spectral energy distribution and spectral types of dwarf O-stars

    NARCIS (Netherlands)

    Mokiem, MR; Martin-Hernandez, NL; Lenorzer, A; de Koter, A; Tielens, AGGA

    We present a systematic study of the effect of metallicity on the stellar spectral energy distribution (SED) of 0 main sequence (dwarf) stars, focussing on the hydrogen and helium ionizing continua, and on the optical and near-IR lines used for spectral classification. The spectra are based on

  8. Metallicity and the spectral energy distribution and spectral types of dwarf O-stars

    NARCIS (Netherlands)

    Mokiem, M.R.; Martín-Hernández, N.L.; Lenorzer, A.; de Koter, A.; Tielens, A.G.G.M.

    2004-01-01

    We present a systematic study of the effect of metallicity on the stellar spectral energy distribution (SED) of O main sequence (dwarf) stars, focussing on the hydrogen and helium ionizing continua, and on the optical and near-IR lines used for spectral classification. The spectra are based on

  9. Analysis of Precursors Prior to Rock Burst in Granite Tunnel Using Acoustic Emission and Far Infrared Monitoring

    OpenAIRE

    Liang, Zhengzhao; Liu, Xiangxin; Zhang, Yanbo; Tang, Chunan

    2013-01-01

    To understand the physical mechanism of the anomalous behaviors observed prior to rock burst, the acoustic emission (AE) and far infrared (FIR) techniques were applied to monitor the progressive failure of a rock tunnel model subjected to biaxial stresses. Images of fracturing process, temperature changes of the tunnel, and spatiotemporal serials of acoustic emission were simultaneously recorded during deformation of the model. The b-value derived from the amplitude distribution data of AE wa...

  10. MIRI: A multichannel far-infrared laser interferometer for electron density measurements on TFTR [Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    Mansfield, D.K.; Park, H.K.; Johnson, L.C.; Anderson, H.M.; Chouinard, R.; Foote, V.S.; Ma, C.H.; Clifton, B.J.

    1987-07-01

    A ten-channel far-infrared laser interferometer which is routinely used to measure the spatial and temporal behavior of the electron density profile on the TFTR tokamak is described and representative results are presented. This system has been designed for remote operation in the very hostile environment of a fusion reactor. The possible expansion of the system to include polarimetric measurements is briefly outlined. 13 refs., 8 figs

  11. Star formation in the inner galaxy: a far-infrared and radio study of two H2 regions

    International Nuclear Information System (INIS)

    Lester, D.F.; Dinerstein, H.L.; Werner, M.W.; Harvey, P.M.; Evans, N.J.II; Brown, R.L.

    1985-12-01

    Far-infrared and radio continuum maps have been made of the central 6' of the inner-galaxy H II regions G30.8-0.0 (in the W43 complex) and G25.4-02., along with radio and molecular line measurements at selected positions. An effort is made to understand far infrared wavelingths allow the dust temperature structures and total far infrared fluxes to be determined. Comparison of the radio and infrared maps shows a close relationship between the ionized gas and the infrared-emitting material. There is evidence that parts of G30.8 are substantially affected by extinction, even at far-infrared wavelengths. For G25.4-0.2, the radio recombination line and CO line data permit resolution of the distance ambiguity for this source. The confusion in distance determination is found to result from an extraordinary near-superposition of two bright H II regions. Using revised distances of 4.3 kpc for G26.4SE and 12 kpc for G25.4NW, that the latter, which is apparently the fainter of the two sources, is actually the more luminous. Though it is not seen on the Palomar Sky Survey, G25.4SE is easily visible in the 9532A line of S III and is mapped in this line. The ratio of total luminosity to ionizing luminosity is very similar to that of H II regions in the solar circle. Assuming a coeval population of ionizing stars, a normal initial mass function is indicated

  12. Star formation in the inner galaxy: a far-infrared and radio study of two H2 regions

    International Nuclear Information System (INIS)

    Lester, D.F.; Dinerstein, H.L.; Werner, M.W.; Harvey, P.M.; Evans, N.J.; Brown, R.L.

    1985-09-01

    Far-infrared and radio continuum maps have been made of the central 6' of the inner-galaxy HII regions G30.8-0.0 (in the W43 complex) and G25.4-0.2, along with radio and molecular line measurements at selected positions. The purpose of this study is an effort to understand star formation in the molecular ring at 5 kpc in galactic radius. Measurements at several far infrared wavelengths allow the dust temperature structures and total far infrared fluxes to be determined. Comparison of the radio and infrared maps shows a close relationship between the ionized gas and the infrared-emitting material. There is evidence that parts of G30.8 are substantially affected by extinction, even at far-infrared wavelengths. Using radio recombination line and CO line data for G25.4-0.2, the distance ambiguity for this source is resolved. The large distance previously ascribed to the entire complex is found to apply to only one of the two main components. The confusion in distance determination is found to result from an extraordinary near-superposition of two bright HII regions. Using the revised distances of 4.3 kpc for G25.4SE and 12 kpc for G25.4NW, it is found that the latter, which is apparently the fainter of the two sources, is actually the more luminous. The ratio of total luminosity to ionizing luminosity is very similar to that of HII regions in the solar circle. Assuming a coeval population of ionizing stars, a normal initial mass function is indicated

  13. Determination of carbohydrates in Folium Lysium Chinensis using capillary electrophoresis combined with far-infrared light irradiation-assisted extraction.

    Science.gov (United States)

    Fu, Yuejiao; Zhang, Luyan; Chen, Gang

    2011-11-01

    In this work, a method based on capillary electrophoresis with amperometric detection and far-infrared-assisted extraction has been developed for the determination of mannitol, sucrose, glucose and fructose in Folium Lysium Chinensis, a commonly used traditional Chinese medicine. The water-soluble constituents in the herbal drug were extracted with double distilled water with the assistance of far-infrared radiations. The effects of detection potential, irradiation time, and the voltage applied on the infrared generator were investigated to acquire the optimum analysis conditions. The detection electrode was a 300-μm-diameter copper disk electrode at a detection potential of +0.65 V. The four carbohydrates could be well separated within 18 min in a 50-cm length fused-silica capillary at a separation voltage of 9 kV in a 50-mM NaOH aqueous solution. The relation between peak current and analyte concentration was linear over about three orders of magnitude with detection limits (S/N=3) ranging from 0.66 to 1.15 μM for all analytes. The results indicated that far infrared significantly enhanced the extraction efficiency of the carbohydrates in Folium Lysium Chinensis. The extraction time was significantly reduced to 7 min compared with several hours for conventional hot solvent extraction. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. CO Spectral Line Energy Distributions of Infrared-Luminous Galaxies and Active Galactic Nuclei

    Science.gov (United States)

    Papadopoulos, Padeli P.; van der Werf, Paul; Isaak, Kate; Xilouris, Emmanuel M.

    2010-06-01

    We report on new sensitive CO J = 6-5 line observations of several luminous infrared galaxies (LIRGs; L IR(8-1000 μm) >~ 1011 L sun), 36% (8/22) of them ultraluminous infrared galaxies (ULIRGs) (L IR>1012 L sun), and two powerful local active galactic nuclei (AGNs)—the optically luminous QSO PG 1119+120 and the powerful radio galaxy 3C 293—using the James Clerk Maxwell Telescope on Mauna Kea in Hawaii. We combine these observations with existing low-J CO data and dust emission spectral energy distributions in the far-infrared-submillimeter from the literature to constrain the properties of the star-forming interstellar medium (ISM) in these systems. We then build the first local CO spectral line energy distributions (SLEDs) for the global molecular gas reservoirs that reach up to high J-levels. These CO SLEDs are neither biased by strong lensing (which affects many of those constructed for high-redshift galaxies), nor suffer from undersampling of CO-bright regions (as most current high-J CO observations of nearby extended systems do). We find: (1) a significant influence of dust optical depths on the high-J CO lines, suppressing the J = 6-5 line emission in some of the most IR-luminous LIRGs, (2) low global CO line excitation possible even in vigorously star-forming systems, (3) the first case of a shock-powered high-excitation CO SLED in the radio galaxy 3C 293 where a powerful jet-ISM interaction occurs, and (4) unusually highly excitated gas in the optically powerful QSO PG 1119+120. In Arp 220 and possibly other (U)LIRGs very faint CO J = 6-5 lines can be attributed to significant dust optical depths at short submillimeter wavelengths immersing those lines in a strong dust continuum, and also causing the C+ line luminosity deficit often observed in such extreme starbursts. Re-analysis of the CO line ratios available for submillimeter galaxies suggests that similar dust opacities also may be present in these high-redshift starbursts, with genuinely low

  15. CO SPECTRAL LINE ENERGY DISTRIBUTIONS OF INFRARED-LUMINOUS GALAXIES AND ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Papadopoulos, Padeli P.; Van der Werf, Paul; Isaak, Kate; Xilouris, Emmanuel M.

    2010-01-01

    We report on new sensitive CO J = 6-5 line observations of several luminous infrared galaxies (LIRGs; L IR (8-1000 μm) ∼> 10 11 L sun ), 36% (8/22) of them ultraluminous infrared galaxies (ULIRGs) (L IR >10 12 L sun ), and two powerful local active galactic nuclei (AGNs)-the optically luminous QSO PG 1119+120 and the powerful radio galaxy 3C 293-using the James Clerk Maxwell Telescope on Mauna Kea in Hawaii. We combine these observations with existing low-J CO data and dust emission spectral energy distributions in the far-infrared-submillimeter from the literature to constrain the properties of the star-forming interstellar medium (ISM) in these systems. We then build the first local CO spectral line energy distributions (SLEDs) for the global molecular gas reservoirs that reach up to high J-levels. These CO SLEDs are neither biased by strong lensing (which affects many of those constructed for high-redshift galaxies), nor suffer from undersampling of CO-bright regions (as most current high-J CO observations of nearby extended systems do). We find: (1) a significant influence of dust optical depths on the high-J CO lines, suppressing the J = 6-5 line emission in some of the most IR-luminous LIRGs, (2) low global CO line excitation possible even in vigorously star-forming systems, (3) the first case of a shock-powered high-excitation CO SLED in the radio galaxy 3C 293 where a powerful jet-ISM interaction occurs, and (4) unusually highly excitated gas in the optically powerful QSO PG 1119+120. In Arp 220 and possibly other (U)LIRGs very faint CO J = 6-5 lines can be attributed to significant dust optical depths at short submillimeter wavelengths immersing those lines in a strong dust continuum, and also causing the C + line luminosity deficit often observed in such extreme starbursts. Re-analysis of the CO line ratios available for submillimeter galaxies suggests that similar dust opacities also may be present in these high-redshift starbursts, with genuinely low

  16. Modeling Well Sampled Composite Spectral Energy Distributions of Distant Galaxies via an MCMC-driven Inference Framework

    Science.gov (United States)

    Pasha, Imad; Kriek, Mariska; Johnson, Benjamin; Conroy, Charlie

    2018-01-01

    Using a novel, MCMC-driven inference framework, we have modeled the stellar and dust emission of 32 composite spectral energy distributions (SEDs), which span from the near-ultraviolet (NUV) to far infrared (FIR). The composite SEDs were originally constructed in a previous work from the photometric catalogs of the NEWFIRM Medium-Band Survey, in which SEDs of individual galaxies at 0.5 MIPS 24 μm was added for each SED type, and in this work, PACS 100 μm, PACS160 μm, SPIRE 25 μm, and SPIRE 350 μm photometry have been added to extend the range of the composite SEDs into the FIR. We fit the composite SEDs with the Prospector code, which utilizes an MCMC sampling to explore the parameter space for models created by the Flexible Stellar Population Synthesis (FSPS) code, in order to investigate how specific star formation rate (sSFR), dust temperature, and other galaxy properties vary with SED type.This work is also being used to better constrain the SPS models within FSPS.

  17. TALC, a new deployable concept for a 20 m far-infrared space telescope

    International Nuclear Information System (INIS)

    Durand, Gilles; Sauvage, Marc; Rodriguez, Louis; Ronayette, Samuel; Reveret, Vincent; Aussel, Herve; Pantin, Eric; Berthe, Michel; Martignac, Jerome; Motte, Frederique; Talvard, Michel; Minier, Vincent; Scola, Loris; Carty, Michael

    2014-01-01

    TALC, Thin Aperture Light Collector is a 20 m space observatory project exploring some unconventional optical solutions (between the single dish and the interferometer) allowing the resolving power of a classical 27 m telescope. With TALC, the principle is to remove the central part of the prime mirror dish, cut the remaining ring into 24 sectors and store them on top of one-another. The aim of this far infrared telescope is to explore the 600 μm to 100 μm region. With this approach we have shown that we can store a ring-telescope of outer diameter 20 m and ring thickness of 3 m inside the fairing of Ariane 5 or Ariane 6. The general structure is the one of a bicycle wheel, whereas the inner sides of the segments are in compression to each other and play the rule of a rim. The segments are linked to each other using a pantograph scissor system that let the segments extend from a pile of dishes to a parabolic ring keeping high stiffness at all time during the deployment. The inner corners of the segments are linked to a central axis using spokes as in a bicycle wheel. The secondary mirror and the instrument box are built as a solid unit fixed at the extremity of the main axis. The tensegrity analysis of this structure shows a very high stiffness to mass ratio, resulting into 3 Hz Eigen frequency. The segments will consist of two composite skins and honeycomb CFRP structure build by replica process. Solid segments will be compared to deformable segments using the controlled shear of the rear surface. The adjustment of the length of the spikes and the relative position of the side of neighbor segments let control the phasing of the entire primary mirror. The telescope is cooled by natural radiation. It is protected from sun radiation by a large inflatable solar screen, loosely linked to the telescope. The orientation is performed by inertia-wheels. This telescope carries a wide field bolometer camera using cryo-cooler at 0.3 K as one of the main instruments. This

  18. TALC: a new deployable concept for a 20m far-infrared space telescope

    Science.gov (United States)

    Durand, Gilles; Sauvage, Marc; Bonnet, Aymeric; Rodriguez, Louis; Ronayette, Samuel; Chanial, Pierre; Scola, Loris; Révéret, Vincent; Aussel, Hervé; Carty, Michael; Durand, Matthis; Durand, Lancelot; Tremblin, Pascal; Pantin, Eric; Berthe, Michel; Martignac, Jérôme; Motte, Frédérique; Talvard, Michel; Minier, Vincent; Bultel, Pascal

    2014-08-01

    TALC, Thin Aperture Light Collector is a 20 m space observatory project exploring some unconventional optical solutions (between the single dish and the interferometer) allowing the resolving power of a classical 27 m telescope. With TALC, the principle is to remove the central part of the prime mirror dish, cut the remaining ring into 24 sectors and store them on top of one-another. The aim of this far infrared telescope is to explore the 600 μm to 100 μm region. With this approach we have shown that we can store a ring-telescope of outer diameter 20m and ring thickness of 3m inside the fairing of Ariane 5 or Ariane 6. The general structure is the one of a bicycle wheel, whereas the inner sides of the segments are in compression to each other and play the rule of a rim. The segments are linked to each other using a pantograph scissor system that let the segments extend from a pile of dishes to a parabolic ring keeping high stiffness at all time during the deployment. The inner corners of the segments are linked to a central axis using spokes as in a bicycle wheel. The secondary mirror and the instrument box are built as a solid unit fixed at the extremity of the main axis. The tensegrity analysis of this structure shows a very high stiffness to mass ratio, resulting into 3 Hz Eigen frequency. The segments will consist of two composite skins and honeycomb CFRP structure build by replica process. Solid segments will be compared to deformable segments using the controlled shear of the rear surface. The adjustment of the length of the spikes and the relative position of the side of neighbor segments let control the phasing of the entire primary mirror. The telescope is cooled by natural radiation. It is protected from sun radiation by a large inflatable solar screen, loosely linked to the telescope. The orientation is performed by inertia-wheels. This telescope carries a wide field bolometer camera using cryocooler at 0.3K as one of the main instruments. This

  19. Herschel GASPS spectral observations of T Tauri stars in Taurus. Unraveling far-infrared line emission from jets and discs

    NARCIS (Netherlands)

    Alonso-Martínez, M.; Riviere-Marichalar, P.; Meeus, G.; Kamp, I.; Fang, M.; Podio, L.; Dent, W. R. F.; Eiroa, C.

    2017-01-01

    Context. At early stages of stellar evolution young stars show powerful jets and/or outflows that interact with protoplanetary discs and their surroundings. Despite the scarce knowledge about the interaction of jets and/or outflows with discs, spectroscopic studies based on Herschel and ISO data

  20. The radio spectral energy distribution of infrared-faint radio sources

    Science.gov (United States)

    Herzog, A.; Norris, R. P.; Middelberg, E.; Seymour, N.; Spitler, L. R.; Emonts, B. H. C.; Franzen, T. M. O.; Hunstead, R.; Intema, H. T.; Marvil, J.; Parker, Q. A.; Sirothia, S. K.; Hurley-Walker, N.; Bell, M.; Bernardi, G.; Bowman, J. D.; Briggs, F.; Cappallo, R. J.; Callingham, J. R.; Deshpande, A. A.; Dwarakanath, K. S.; For, B.-Q.; Greenhill, L. J.; Hancock, P.; Hazelton, B. J.; Hindson, L.; Johnston-Hollitt, M.; Kapińska, A. D.; Kaplan, D. L.; Lenc, E.; Lonsdale, C. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Morgan, J.; Oberoi, D.; Offringa, A.; Ord, S. M.; Prabu, T.; Procopio, P.; Udaya Shankar, N.; Srivani, K. S.; Staveley-Smith, L.; Subrahmanyan, R.; Tingay, S. J.; Wayth, R. B.; Webster, R. L.; Williams, A.; Williams, C. L.; Wu, C.; Zheng, Q.; Bannister, K. W.; Chippendale, A. P.; Harvey-Smith, L.; Heywood, I.; Indermuehle, B.; Popping, A.; Sault, R. J.; Whiting, M. T.

    2016-10-01

    Context. Infrared-faint radio sources (IFRS) are a class of radio-loud (RL) active galactic nuclei (AGN) at high redshifts (z ≥ 1.7) that are characterised by their relative infrared faintness, resulting in enormous radio-to-infrared flux density ratios of up to several thousand. Aims: Because of their optical and infrared faintness, it is very challenging to study IFRS at these wavelengths. However, IFRS are relatively bright in the radio regime with 1.4 GHz flux densities of a few to a few tens of mJy. Therefore, the radio regime is the most promising wavelength regime in which to constrain their nature. We aim to test the hypothesis that IFRS are young AGN, particularly GHz peaked-spectrum (GPS) and compact steep-spectrum (CSS) sources that have a low frequency turnover. Methods: We use the rich radio data set available for the Australia Telescope Large Area Survey fields, covering the frequency range between 150 MHz and 34 GHz with up to 19 wavebands from different telescopes, and build radio spectral energy distributions (SEDs) for 34 IFRS. We then study the radio properties of this class of object with respect to turnover, spectral index, and behaviour towards higher frequencies. We also present the highest-frequency radio observations of an IFRS, observed with the Plateau de Bure Interferometer at 105 GHz, and model the multi-wavelength and radio-far-infrared SED of this source. Results: We find IFRS usually follow single power laws down to observed frequencies of around 150 MHz. Mostly, the radio SEDs are steep (α IFRS show statistically significantly steeper radio SEDs than the broader RL AGN population. Our analysis reveals that the fractions of GPS and CSS sources in the population of IFRS are consistent with the fractions in the broader RL AGN population. We find that at least % of IFRS contain young AGN, although the fraction might be significantly higher as suggested by the steep SEDs and the compact morphology of IFRS. The detailed multi

  1. Safeguards applications of far infrared radiometric techniques for the detection of contraband

    Energy Technology Data Exchange (ETDEWEB)

    Hodges, D.T.; Reber, E.E.; Foote, F.B.; Schellenbaum, R.L.

    1980-02-01

    A new safeguards system under development employs radiometers in the 100 to 300 GHz spectral band to detect contraband, including shielding materials (used to attenuate the gamma ray emissions from nuclear materials), weapons, or explosives covertly concealed on personnel. Clothing is highly transparent at these frequencies and imaging techniques can detect contraband by its emissivity and reflectivity differences relative to human tissues. Experimental data are presented and sample images are used as a basis to discuss system advantages and limitations.

  2. Safeguards applications of far infrared radiometric techniques for the detection of contraband

    International Nuclear Information System (INIS)

    Hodges, D.T.; Reber, E.E.; Foote, F.B.; Schellenbaum, R.L.

    1980-02-01

    A new safeguards system under development employs radiometers in the 100 to 300 GHz spectral band to detect contraband, including shielding materials (used to attenuate the gamma ray emissions from nuclear materials), weapons, or explosives covertly concealed on personnel. Clothing is highly transparent at these frequencies and imaging techniques can detect contraband by its emissivity and reflectivity differences relative to human tissues. Experimental data are presented and sample images are used as a basis to discuss system advantages and limitations

  3. Effect of nano-sized cerium-zirconium oxide solid solution on far-infrared emission properties of tourmaline powders

    Science.gov (United States)

    Guo, Bin; Yang, Liqing; Hu, Weijie; Li, Wenlong; Wang, Haojing

    2015-10-01

    Far-infrared functional nanocomposites were prepared by the co-precipitation method using natural tourmaline (XY3Z6Si6O18(BO3)3V3W, where X is Na+, Ca2+, K+, or vacancy; Y is Mg2+, Fe2+, Mn2+, Al3+, Fe3+, Mn3+, Cr3+, Li+, or Ti4+; Z is Al3+, Mg2+, Cr3+, or V3+; V is O2-, OH-; and W is O2-, OH-, or F-) powders, ammonium cerium(IV) nitrate and zirconium(IV) nitrate pentahydrate as raw materials. The reference sample, tourmaline modified with ammonium cerium(IV) nitrate alone was also prepared by a similar precipitation route. The results of Fourier transform infrared spectroscopy show that tourmaline modified with Ce and Zr has a better far-infrared emission property than tourmaline modified with Ce alone. Through characterization by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), the mechanism for oxygen evolution during the heat process in the two composite materials was systematically studied. The XPS spectra show that Fe3+ ratio inside tourmaline modified with Ce alone can be raised by doping Zr. Moreover, it is showed that there is a higher Ce3+ ratio inside the tourmaline modified with Ce and Zr than tourmaline modified with Ce alone. In addition, XRD results indicate the formation of CeO2 and Ce1-xZrxO2 crystallites during the heat treatment and further TEM observations show they exist as nanoparticles on the surface of tourmaline powders. Based on these results, we attribute the improved far-infrared emission properties of Ce-Zr doped tourmaline to the enhanced unit cell shrinkage of the tourmaline arisen from much more oxidation of Fe2+ to Fe3+ inside the tourmaline caused by the change in the catalyst redox properties of CeO2 brought about by doping with Zr4+. In all samples, tourmaline modified with 7.14 wt.% Ce and 1.86 wt.% Zr calcined at 800∘C for 5 h has the best far-infrared emission property with the maximum emissivity value of 98%.

  4. NGC 985 - Extended ionized regions and the far-infrared luminosity of a ring-shaped Seyfert galaxy

    International Nuclear Information System (INIS)

    Rodriguez Espinosa, J.M.; Stanga, R.M.

    1990-01-01

    Narrow-band H-alpha images and long-slit spectroscopy of the Seyfert galaxy NGC 985 are presented. Large-scale extended ionized zones are seen to cover a significant fraction of the ring of this object. These ionized zones are responsible for a considerable fraction (greater than 35 percent) of the far-infrared emission of NGC 985. These ionized zones are interpreted as giant H II region complexes, formed in a recent burst of star formation. It is also argued that that starburst was triggered by a galaxy interaction. 41 refs

  5. Metal-Insulator Phase Transition in thin VO2 films: A Look from the Far Infrared Side

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd; Fischer, B. M.; Thoman, A.

    Vanadium dioxide (VO2) displays a well-known metal-insulator (MI) transition at atemperature of 68oC. The MI transition in VO2 has been studied extensively by a widerange of optical, electrical, structural, and magnetic measurements. In spite of this there isstill some controversy about the nature...... temperature hysteresis of the far-infrared transmission through thethin film with temperature. Interestingly the temperature-dependent transmissionamplitude shows a markedly different switching temperature than the transmission phase.This effect has not been observed before, and is very important...

  6. The broadband spectral energy distributions of SDSS blazars

    Science.gov (United States)

    Li, Huai-Zhen; Chen, Luo-En; Jiang, Yun-Guo; Yi, Ting-Feng

    2015-07-01

    We compiled the radio, optical and X-ray data of blazars from the Sloan Digital Sky Survey database, and presented the distribution of luminosities and broadband spectral indices. The distribution of luminosities shows that the averaged luminosity of flat spectrum radio quasars (FSRQs) is larger than that of BL Lacertae (BL Lac) objects. On the other hand, the broadband spectral energy distribution reveals that FSRQs and low energy peaked BL Lac objects have similar spectral properties, but high energy peaked BL Lac objects have a distinct spectral property. This may be due to the fact that different subclasses of blazars have different intrinsic environments and are at different cooling levels. Even so, a unified scheme is also revealed from the color-color diagram, which hints that there are similar physical processes operating in all objects under a range of intrinsic physical conditions or beaming parameters. Supported by the National Natural Science Foundation of China.

  7. UV TO FAR-IR CATALOG OF A GALAXY SAMPLE IN NEARBY CLUSTERS: SPECTRAL ENERGY DISTRIBUTIONS AND ENVIRONMENTAL TRENDS

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Fernandez, Jonathan D.; Iglesias-Paramo, J.; Vilchez, J. M., E-mail: jonatan@iaa.es [Instituto de Astrofisica de Andalucia, Glorieta de la Astronomia s/n, 18008 Granada (Spain)

    2012-03-01

    In this paper, we present a sample of cluster galaxies devoted to study the environmental influence on the star formation activity. This sample of galaxies inhabits in clusters showing a rich variety in their characteristics and have been observed by the SDSS-DR6 down to M{sub B} {approx} -18, and by the Galaxy Evolution Explorer AIS throughout sky regions corresponding to several megaparsecs. We assign the broadband and emission-line fluxes from ultraviolet to far-infrared to each galaxy performing an accurate spectral energy distribution for spectral fitting analysis. The clusters follow the general X-ray luminosity versus velocity dispersion trend of L{sub X} {proportional_to} {sigma}{sup 4.4}{sub c}. The analysis of the distributions of galaxy density counting up to the 5th nearest neighbor {Sigma}{sub 5} shows: (1) the virial regions and the cluster outskirts share a common range in the high density part of the distribution. This can be attributed to the presence of massive galaxy structures in the surroundings of virial regions. (2) The virial regions of massive clusters ({sigma}{sub c} > 550 km s{sup -1}) present a {Sigma}{sub 5} distribution statistically distinguishable ({approx}96%) from the corresponding distribution of low-mass clusters ({sigma}{sub c} < 550 km s{sup -1}). Both massive and low-mass clusters follow a similar density-radius trend, but the low-mass clusters avoid the high density extreme. We illustrate, with ABELL 1185, the environmental trends of galaxy populations. Maps of sky projected galaxy density show how low-luminosity star-forming galaxies appear distributed along more spread structures than their giant counterparts, whereas low-luminosity passive galaxies avoid the low-density environment. Giant passive and star-forming galaxies share rather similar sky regions with passive galaxies exhibiting more concentrated distributions.

  8. Downwelling Far-Infrared Emission Spectra Measured By First at Cerro Toco, Chile and Table Mountain, California

    Science.gov (United States)

    Mast, J. C.; Mlynczak, M. G.; Cageao, R.; Kratz, D. P.; Johnson, D. G.; Mlawer, E. J.; Turner, D. D.

    2014-12-01

    The Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument is a Fourier transform spectrometer developed to measure the important far-infrared spectrum between 100 and 650 cm-1. Presented here are measurements made by FIRST during two successful deployments in a ground-based configuration to measure downwelling longwave radiation at Earth's surface. The initial deployment was to Cerro Toco, Chile, where FIRST operated from August to October, 2009 as part of the Radiative Heating in Underexplored Bands Campaign (RHUBC-II) campaign. After recalibration, FIRST was deployed to the Table Mountain Facility from September through October, 2012. Spectra observed at each location are substantially different, due in large part to the order of magnitude difference in integrated precipitable water vapor (0.3 cm at Table Mountain, 0.03 cm at Cerro Toco). Dry days for both campaigns are chosen for analysis - 09/24/2009 and 10/19/2012. Also available during both deployments are coincident radiosonde temperature and water vapor vertical profiles which are used as inputs a line-by-line radiative transfer program. Comparisons between measured and modeled spectra are presented over the 200 to 800 cm-1 range. An extensive error analysis of both the measured and modeled spectra is presented. In general, the differences between the measured and modeled spectra are within their combined uncertainties.

  9. The source of multi spectral energy of solar energetic electron

    Energy Technology Data Exchange (ETDEWEB)

    Herdiwijaya, Dhani [Astronomy Division and Bosscha Observatory, Faculty Mathematics and Natural Sciences, Intitute Technology of Bandung, Ganesha 10, Bandung, Indonesia 40132 dhani@as.itb.ac.id (Indonesia)

    2015-04-16

    We study the solar energetic electron distribution obtained from ACE and GOES satellites which have different altitudes and electron spectral energy during the year 1997 to 2011. The electron spectral energies were 0.038–0.315 MeV from EPAM instrument onboard ACE satellite and >2 MeV from GOES satellite. We found that the low electron energy has no correlation with high energy. In spite of we have corrected to the altitude differences. It implied that they originated from time dependent events with different sources and physical processes at the solar atmosphere. The sources of multi spectral energetic electron were related to flare and CME phenomena. However, we also found that high energetic electron comes from coronal hole.

  10. Visual Method for Spectral Energy Distribution Calculation of ...

    Indian Academy of Sciences (India)

    Abstract. In this work, we propose to use 'The Geometer's Sketchpad' to the fitting of a spectral energy distribution of blazar based on three effective spectral indices, αRO, αOX, and αRX and the flux density in the radio band. It can make us to see the fitting in detail with both the peak frequency and peak luminosity given ...

  11. Measuring the Evolution of Stellar Populations And Gas Metallicity in Galaxies with Far-Infrared Space Spectroscopy

    Science.gov (United States)

    Stacey, Gordon

    We propose a study of the evolution of stellar populations and gas metallicities in about 80 nearby star forming galaxies based on mining the NASA data archives for observations of the [NIII] 57 µm, [OIII] 52 µm and/or 88 µm, [NII] 122 and [CII] 158 µm far-infrared (FIR) fine- structure lines and other archives for thermal radio continuum. These lines are powerful probes of both stellar populations and gas properties and our primary science derives from these tracers. For sources that show both signs of active galactic nuclei (AGN) and star formation, we will take advantage of the readily available NASA Spitzer IRS data base that includes mid-IR [NeII] 12.8 µm, [NeIII] 15.6 µm and [NeV] 14.3 µm, [OIV] 25.9 µm and PAH observations. These complementary data reveal the relative fractions of the FIR line emission that might arise from star formation and the narrow line regions (NLR) associated with an AGN, thereby providing a robust set of observations to compare with star formation models. Subsets of the FIR lines have been detected from hundreds of nearby galaxies. From both theoretical studies and the results of these pioneering observations we know that these lines can be powerful probes of stellar populations and star formation in galaxies. Here we plan to use various combinations of the lines to constrain (1) the age of the stellar populations (through lines that trace the hardness of the stellar radiation fields, hence stellar spectral type), (2) the degree of processing of the interstellar medium (through lines that trace growth of secondary to primary element abundances for example, the N/O ratio), (3) the efficiency of star formation (through growth in absolute abundances of N and O, the N/H and O/H ratios), and (4) the current day mass function of upper main sequence stars. Surprisingly, there has been no systematic study of the large sample of these line detections made with PACS on Herschel in order to truly assess and calibrate their diagnostic

  12. Recent Advances in Laboratory Infrared Spectroscopy of Polycyclic Aromatic Hydrocarbons: PAHs in the Far Infrared

    Science.gov (United States)

    Mattioda, Andrew L.; Ricca, Alessandra; Tucker, Jonathan; Boersma, Christiaan; Bauschlicher, Charles, Jr.; Allamandola, Louis J.

    2010-01-01

    Over 25 years of observations and laboratory work have shown that the mid-IR spectra of a majority of astronomical sources are dominated by emission features near 3.3, 6.2, 7.7, and 11.2 microns, which originate in free polycyclic aromatic hydrocarbon (PAH) molecules. PAHs dominate the mid-IR emission from many galactic and extragalactic objects. As such, this material tracks a wide variety of astronomical processes, making this spectrum a powerful probe of the cosmos Apart from bands in the mid-IR, PAHs have bands spanning the Far-IR (FIR) and emission from these FIR features should be present in astronomical sources showing the Mid-IR PAH bands. However, with one exception, the FIR spectral characteristics are known only for a few neutral small PAHs trapped in salt pellets or oils at room temperature, data which is not relevant to astrophysics. Furthermore, since most emitting PAHs responsible for the mid-IR astronomical features are ionized, the absence of any experimental or theoretical PAH ion FIR spectra will make it impossible to correctly interpret the FIR data from these objects. In view of the upcoming Herschel space telescope mission and SOFIA's FIR airborne instrumentation, which will pioneer the FIR region, it is now urgent to obtain PAH FIR spectra. This talk will present an overview recent advances in the laboratory spectroscopy of PAHs, Highlighting the FIR spectroscopy along with some quantum calculations.

  13. Measured and Modeled Downwelling Far-Infrared Radiances in Very Dry Environments and Calibration Requirements for Future Experiments

    Science.gov (United States)

    Mast, J. C.; Mlynczak, M. G.; Cageao, R.; Kratz, D. P.; Latvakoski, H.; Johnson, D. G.; Mlawer, E. J.; Turner, D. D.

    2016-12-01

    Downwelling radiances measured by the Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument in an environment with integrated precipitable water as low as 0.03 cm are compared with calculated spectra in the far-infrared and mid-infrared. In its current ground-based configuration FIRST was deployed to 5.38 km on Cerro Toco, a mountain in the Atacama Desert of Chile, from August to October 2009. There FIRST took part in the Radiative Heating in Unexplored Bands Campaign Part 2. Water vapor and temperature profiles from an optimal-estimation-based physical retrieval algorithm (using simultaneous radiosonde and multichannel 183 GHz microwave radiometer measurements) are input to the AER Line-by-Line Radiative Transfer Model (LBLRTM) to compute radiances for comparison with FIRST. The AER v3.4 line parameter database is used. The low water vapor amounts and relatively cold atmosphere result in extremely small far-IR radiances (1.5 mW/m2/sr/cm-1) with corresponding brightness temperatures of 120 K. The residual LBLRTM minus FIRST is calculated to assess agreement between the measured and modeled spectra. Uncertainties in both the measured and modeled radiances are accounted for in the comparison. A goal of the deployment and subsequent analysis is the assessment of water vapor spectroscopy in the far-infrared and mid-infrared. While agreement is found between measured and modeled radiances within the combined uncertainties across all spectra, uncertainties in the measured water vapor profiles and from the laboratory calibration exceed those associated with water vapor spectroscopy in this very low radiance environment. Consequently, no improvement in water vapor spectroscopy is afforded by these measurements. However, we use these results to place requirements on instrument calibration accuracy and water vapor profile accuracy for future campaigns to similarly dry environments. Instrument calibration uncertainty needs to be at 2% (1-sigma) of measured radiance

  14. Improved ice particle optical property simulations in the ultraviolet to far-infrared regime

    International Nuclear Information System (INIS)

    Bi, Lei; Yang, Ping

    2017-01-01

    To derive the bulk radiative properties of ice clouds, aircraft contrails and snow grains, which are fundamental to atmospheric radiative transfer calculations in downstream applications, it is necessary to accurately simulate the scattering of light by individual ice particles. An ice particle optical property database reported in 2013 (hereafter, TAMUice2013) is updated (hereafter, TAMUice2016) to incorporate recent advances in computation of the optical properties of nonspherical particles. Specifically, we employ the invariant imbedding T-matrix (II-TM) method to compute the optical properties of particles with small to moderate size parameters. Both versions use the Improved Geometric Optics Method (IGOM) to compute the optical properties of large ice crystals, but TAMUice2016 improves the treatment of inhomogeneous waves inside the scattering particles in the case where ice is absorptive such as at infrared wavelengths. To bridge the gap between the extinction efficiencies computed from the II-TM and the IGOM, TAMUice2016 includes spectrally dependent higher order terms of the edge effect in addition to the first order counterpart considered in TAMUice2013. Furthermore, the differences between TAMUice2013 and TAMUice2016 are quantified with respect to the computation of the bulk optical properties of ice clouds. - Highlights: • A previous database of the single-scattering properties of ice crystals is improved. • A combination of the invariant imbedding T-matrix and improved geometric optics methods is used. • The treatment of inhomogeneous waves in an absorptive ice crystal is improved. • Higher order terms of the edge effect are considered in the updated database.

  15. Diffuse X-ray scattering and far infrared absorption of barium and lead β" aluminas

    DEFF Research Database (Denmark)

    Hayes, W.; Kjær, Kristian; Pratt, F. L.

    1985-01-01

    The authors have carried out high-momentum-resolution studies in diffuse X-ray scattering of barium and lead B" aluminas in the temperature range 20-700 degrees C. They have also measured the vibrational spectra of these compounds between 2K and 300K in the energy range 10-100 cm-1. The results...

  16. Present status of the development of far-infrared coherent light sources with the ISIR linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Okuda, Shuichi [Osaka Univ., Ibaraki (Japan). Inst. of Scientific and Industrial Research

    1996-07-01

    Far-infrared light sources are being developed with a 38-MeV L-band linear accelerator at the Institute of Scientific and Industrial Research, Osaka University. In the experiments of free-electron laser the self-amplified spontaneous emission was observed at wavelengths of 20 and 40 {mu}m with a high-intensity single-bunch beam for a single passage through a wiggler. In the free-electron laser oscillation experiments with a multibunch beam laser light was obtained at wavelengths from 32 to 40 {mu}m. The peak power in a micropulse of the laser was estimated to be 8.3 MW at a wavelength of 40 {mu}m. Coherent radiation emitted from bunched electrons was observed for Cherenkov and transition radiation processes with the single-bunch beam. (author)

  17. A far-infrared Michelson interferometer for tokamak electron density measurements using computer-generated reference fringes

    International Nuclear Information System (INIS)

    Krug, P.A.; Stimson, P.A.; Falconer, I.S.

    1986-01-01

    A simple far-infrared interferometer which uses the 394 μm laser line from optically-pumped formic acid vapour to measure tokamak electron density is described. This interferometer is unusual in requiring only one detector and a single probing beam since reference fringes during the plasma shot are obtained by computer interpolation between the fringes observed immediately before and after the shot. Electron density has been measured with a phase resolution corresponding to + - 1/20 wavelength fringe shift, which is equivalent to a central density resolution of + - 0.1 x 10 19 m -3 for an assumed parabolic density distribution in a plasma of diameter of 0.2 m, and with a time resolution of 0.2 ms. (author)

  18. Terahertz time-domain spectroscopy response of amines and amino acids intercalated smectites in far-infrared region

    Energy Technology Data Exchange (ETDEWEB)

    Janek, M., E-mail: marian.janek@fns.uniba.sk [Comenius University, Faculty of Natural Sciences, Department of Physical and Theoretical Chemistry, Mlynská dolina CH1, SK-84215 Bratislava (Slovakia); Zich, D. [Comenius University, Faculty of Natural Sciences, Department of Physical and Theoretical Chemistry, Mlynská dolina CH1, SK-84215 Bratislava (Slovakia); Naftaly, M., E-mail: mira.naftaly@npl.co.uk [National Physical Laboratory, Hampton Rd, Teddington, Middlesex TW11 0LW (United Kingdom)

    2014-06-01

    Layered clay minerals from the smectite group with different chemical composition and resulting layer charge (e.g. pyrophyllite, illite, hectorite and montmorillonite) were characterised for their dielectric properties in the far-infrared region using terahertz-time domain spectroscopy (THz-TDS). Samples with distinct cation exchange capacity such as hectorite and montmorillonite were modified using cation exchange reaction with alkylamines or amino acids. The presence of these species in 2D gallery was proved by X-ray diffraction and Fourier transform infrared spectroscopy. The frequency-dependent refractive index of these minerals was determined in the experimentally accessible range of 0.1–3.0 THz (3–100 cm{sup −1}) using THz-TDS. Pristine samples revealed their refractive indices to be 1.82–2.15 at about 1 THz while the modified montmorillonite samples had their refractive indices changed by organic molecules used for their modification to 1.70–2.35 for amines and 1.97–2.36 for amino acids. The presence of organic substances in 2D gallery of clays was detectable despite the relatively high absorption of smectites with magnitude of 100 cm{sup −1}. - Graphical abstract: Display Omitted - Highlights: • “Guest” molecules in “host” layered material were investigated. • Amines and amino-acids were selected as guest molecules. • Natural and synthetic host with smectite phyllosilicate structure were used. • Dielectric properties were investigated by terahertz time domain spectroscopy. • Resonance absorption peaks of guest were detected in far infrared region.

  19. Advanced far infrared blocked impurity band detectors based on germanium liquid phase epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Christopher Sean [Univ. of California, Berkeley, CA (United States)

    1998-05-01

    This research has shown that epilayers with residual impurity concentrations of 5 x 1013 cm-3 can be grown by producing the purest Pb available in the world. These epilayers have extremely low minority acceptor concentrations, which is ideal for fabrication of IR absorbing layers. The Pb LPE growth of Ge also has the advantageous property of gettering Cu from the epilayer and the substrate. Epilayers have been grown with intentional Sb doping for IR absorption on lightly doped substrates. This research has proven that properly working Ge BIB detectors can be fabricated from the liquid phase as long as pure enough solvents are available. The detectors have responded at proper wavelengths when reversed biased even though the response did not quite reach minimum wavenumbers. Optimization of the Sb doping concentration should further decrease the photoionization energy of these detectors. Ge BIB detectors have been fabricated that respond to 60 cm-1 with low responsivity. Through reduction of the minority residual impurities, detector performance has reached responsivities of 1 A/W. These detectors have exhibited quantum efficiency and NEP values that rival conventional photoconductors and are expected to provide a much more sensitive tool for new scientific discoveries in a number of fields, including solid state studies, astronomy, and cosmology.

  20. Spectral Gap Energy Transfer in Atmospheric Boundary Layer

    Science.gov (United States)

    Bhushan, S.; Walters, K.; Barros, A. P.; Nogueira, M.

    2012-12-01

    Experimental measurements of atmospheric turbulence energy spectra show E(k) ~ k-3 slopes at synoptic scales (~ 600 km - 2000 km) and k-5/3 slopes at the mesoscales (theory, it is expected that a strong backward energy cascade would develop at the synoptic scale, and that circulation would grow infinitely. To limit this backward transfer, energy arrest at macroscales must be introduced. The most commonly used turbulence models developed to mimic the above energy transfer include the energy backscatter model for 2D turbulence in the horizontal plane via Large Eddy Simulation (LES) models, dissipative URANS models in the vertical plane, and Ekman friction for the energy arrest. One of the controversial issues surrounding the atmospheric turbulence spectra is the explanation of the generation of the 2D and 3D spectra and transition between them, for energy injection at the synoptic scales. Lilly (1989) proposed that the existence of 2D and 3D spectra can only be explained by the presence of an additional energy injection in the meso-scale region. A second issue is related to the observations of dual peak spectra with small variance in meso-scale, suggesting that the energy transfer occurs across a spectral gap (Van Der Hoven, 1957). Several studies have confirmed the spectral gap for the meso-scale circulations, and have suggested that they are enhanced by smaller scale vertical convection rather than by the synoptic scales. Further, the widely accepted energy arrest mechanism by boundary layer friction is closely related to the spectral gap transfer. This study proposes an energy transfer mechanism for atmospheric turbulence with synoptic scale injection, wherein the generation of 2D and 3D spectra is explained using spectral gap energy transfer. The existence of the spectral gap energy transfer is validated by performing LES for the interaction of large scale circulation with a wall, and studying the evolution of the energy spectra both near to and far from the wall

  1. Dual-energy contrast-enhanced spectral mammography (CESM).

    Science.gov (United States)

    Daniaux, Martin; De Zordo, Tobias; Santner, Wolfram; Amort, Birgit; Koppelstätter, Florian; Jaschke, Werner; Dromain, Clarisse; Oberaigner, Willi; Hubalek, Michael; Marth, Christian

    2015-10-01

    Dual-energy contrast-enhanced mammography is one of the latest developments in breast care. Imaging with contrast agents in breast cancer was already known from previous magnetic resonance imaging and computed tomography studies. However, high costs, limited availability-or high radiation dose-led to the development of contrast-enhanced spectral mammography (CESM). We reviewed the current literature, present our experience, discuss the advantages and drawbacks of CESM and look at the future of this innovative technique.

  2. Frequency stabilization of an optically pumped far-infrared laser to the harmonic of a microwave synthesizer.

    Science.gov (United States)

    Danylov, A A; Light, A R; Waldman, J; Erickson, N

    2015-12-10

    Measurements of the frequency stability of a far-infrared molecular laser have been made by mixing the harmonic of an ultrastable microwave source with a portion of the laser output signal in a terahertz (THz) Schottky diode balanced mixer. A 3 GHz difference-frequency signal was used in a frequency discriminator circuit to lock the laser to the microwave source. Comparisons of the short- and long-term laser frequency stability under free-running and locked conditions show a significant improvement with locking. Short-term frequency jitter was reduced by an order of magnitude, from approximately 40 to 4 kHz, and long-term drift was reduced by more than three orders of magnitude, from approximately 250 kHz to 80 Hz. The results, enabled by the efficient Schottky diode balanced mixer downconverter, demonstrate that ultrastable microwave-based frequency stabilization of THz optically pumped lasers (OPLs) will now be possible at frequencies extending well above 4.0 THz.

  3. a Question of Mass : Accounting for all the Dust in the Crab Nebula with the Deepest Far Infrared Maps

    Science.gov (United States)

    Matar, J.; Nehmé, C.; Sauvage, M.

    2017-12-01

    Supernovae represent significant sources of dust in the interstellar medium. In this work, deep far-infrared (FIR) observations of the Crab Nebula are studied to provide a new and reliable constraint on the amount of dust present in this supernova remnant. Deep exposures between 70 and 500 μm taken by PACS and SPIRE instruments on-board the Herschel Space Telescope, compiling all observations of the nebula including PACS observing mode calibration, are refined using advanced processing techniques, thus providing the most accurate data ever generated by Herschel on the object. We carefully find the intrinsic flux of each image by masking the source and creating a 2D polynomial fit to deduce the background emission. After subtracting the estimated non-thermal synchrotron component, two modified blackbodies were found to best fit the remaining infrared continuum, the cold component with T_c = 8.3 ± 3.0 K and M_d = 0.27 ± 0.05 M_{⊙} and the warmer component with T_w = 27.2 ± 1.3 K and M_d = (1.3 ± 0.4) ×10^{-3} M_{⊙}.

  4. Analysis of Precursors Prior to Rock Burst in Granite Tunnel Using Acoustic Emission and Far Infrared Monitoring

    Directory of Open Access Journals (Sweden)

    Zhengzhao Liang

    2013-01-01

    Full Text Available To understand the physical mechanism of the anomalous behaviors observed prior to rock burst, the acoustic emission (AE and far infrared (FIR techniques were applied to monitor the progressive failure of a rock tunnel model subjected to biaxial stresses. Images of fracturing process, temperature changes of the tunnel, and spatiotemporal serials of acoustic emission were simultaneously recorded during deformation of the model. The b-value derived from the amplitude distribution data of AE was calculated to predict the tunnel rock burst. The results showed that the vertical stress enhanced the stability of the tunnel, and the tunnels with higher confining pressure demonstrated a more abrupt and strong rock burst. Abnormal temperature changes around the wall were observed prior to the rock burst of the tunnel. Analysis of the AE events showed that a sudden drop and then a quiet period could be considered as the precursors to forecast the rock burst hazard. Statistical analysis indicated that rock fragment spalling occurred earlier than the abnormal temperature changes, and the abnormal temperature occurred earlier than the descent of the AE b-value. The analysis indicated that the temperature changes were more sensitive than the AE b-value changes to predict the tunnel rock bursts.

  5. Micro-Spec: An Ultra-Compact, High-Sensitivity Spectrometer for Far-Infrared and Sub-Millimeter Astronomy

    Science.gov (United States)

    Cataldo, Giuseppe; Hsieh, Wen-Ting; Huang, Wei-Chung; Moseley, S. Harvey; Stevenson, Thomas R.; Wollack, Edward J.

    2013-01-01

    High-performance, integrated spectrometers operating in the far-infrared and sub-millimeter promise to be powerful tools for the exploration of the epochs of reionization and initial galaxy formation. These devices, using high-efficiency superconducting transmission lines, can achieve the performance of a meter-scale grating spectrometer in an instrument implemented on a four-inch silicon wafer. Such a device, when combined with a cryogenic telescope in space, provides an enabling capability for studies of the early universe. Here, the optical design process for Micro-Spec (mu-Spec) is presented, with particular attention given to its two-dimensional diffractive region, where the light of different wavelengths is focused on the different detectors. The method is based on the stigmatization and minimization of the light path function in this bounded region, which results in an optimized geometrical configuration. A point design with an efficiency of approx. 90% has been developed for initial demonstration, and can serve as the basis for future instruments. Design variations on this implementation are also discussed, which can lead to lower efficiencies due to diffractive losses in the multimode region.

  6. Effects of Combined Far-Infrared Radiation and Acupuncture at ST36 on Peripheral Blood Perfusion and Autonomic Activities

    Directory of Open Access Journals (Sweden)

    Cheng-Chan Yang

    2017-01-01

    Full Text Available Using four-channel photoplethysmography (PPG for acquiring peripheral arterial waveforms, this study investigated vascular and autonomic impacts of combined acupuncture-far infrared radiation (FIR in improving peripheral circulation. Twenty healthy young adults aged 25.5±4.6 were enrolled for 30-minute measurement. Each subject underwent four treatment strategies, including acupuncture at ST36 (Zusanli, pseudoacupuncture, FIR, and combined acupuncture-FIR at different time points. Response was assessed at 5-minute intervals. Area under arterial waveform at baseline was defined as AreaBaseline, whereas AreaStim referred to area at each 5-minute substage during and after treatment. AreaStim/AreaBaseline was compared at different stages and among different strategies. Autonomic activity at different stages was assessed using low-to-high frequency power ratio (LHR. The results demonstrated increased perfusion for each therapeutic strategy from stage 1 to stage 2 (all p<0.02. Elevated perfusion was noted for all treatment strategies at stage 3 compared to stage 1 except pseudoacupuncture. Increased LHR was noted only in subjects undergoing pseudoacupuncture at stage 3 compared to stage 1 (p=0.045. Reduced LHR at stage 2 compared to stage 1 was found only in combined treatment group (p=0.041. In conclusion, the results support clinical benefits of combined acupuncture-FIR treatment in enhancing peripheral perfusion and parasympathetic activity.

  7. Transmission Spectra of HgTe-Based Quantum Wells and Films in the Far-Infrared Range

    Science.gov (United States)

    Savchenko, M. L.; Vasil'ev, N. N.; Yaroshevich, A. S.; Kozlov, D. A.; Kvon, Z. D.; Mikhailov, N. N.; Dvoretskii, S. A.

    2018-04-01

    Strained 80-nm-thick HgTe films belong to a new class of materials referred to as three-dimensional topological insulators (i.e., they have a bulk band gap and spin-nondegenerate surface states). Though there are a number of studies devoted to analysis of the properties of surface states using both transport and magnetooptical techniques in the THz range, the information about direct optical transitions between bulk and surface bands in these systems has not been reported. This study is devoted to the analysis of transmission and reflection spectra of HgTe films of different thicknesses in the far-infrared range recorded in a wide temperature range in order to detect the above interband transitions. A peculiarity at 15 meV, which is sensitive to a change in the temperature, is observed in spectra of both types. Detailed analysis of the data obtained revealed that this feature is related to absorption by HgTe optical phonons, while the interband optical transitions are suppressed.

  8. The effect of leg hyperthermia using far infrared rays in bedridden subjects with type 2 diabetes mellitus.

    Science.gov (United States)

    Kawaura, Akihiko; Tanida, Noritoshi; Kamitani, Masato; Akiyama, Junichi; Mizutani, Masatoshi; Tsugawa, Naoko; Okano, Toshio; Takeda, Eiji

    2010-04-01

    We examined the effect of leg hyperthermia on oxidative stress in bedridden subjects with type 2 diabetes mellitus using 15-min sessions of far infrared rays over a two-week period. Four subjects (male 1, female 3) incapacitated by a stroke were recruited for this study. All patients were admitted to Takahashi Central Hospital and ate the same hospital meals. Fasting plasma glucose, HbA1c, tumor necrosis factor (TNF)alpha, free fatty acid, leptin, adiponectin and plasma 8-epi-prostaglandin F2alpha (8-epi-PGF2alpha) levels as a marker of oxidative stress were measured on admission, just before and 2 weeks after local heating of the leg. Results showed that plasma total 8-epi-PGF2alpha levels were decreased significantly while TNFalpha levels were increased significantly. On the other hand, glucose, HbA1c, free fatty acid, leptin and adiponectin levels were not changed during the study period. These results suggest that repeated leg hyperthermia may protect against oxidative stress.

  9. REGIONAL VARIATIONS IN THE DENSE GAS HEATING AND COOLING IN M51 FROM HERSCHEL FAR-INFRARED SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Parkin, T. J.; Wilson, C. D.; Schirm, M. R. P.; Foyle, K. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Baes, M.; De Looze, I. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Boquien, M.; Boselli, A. [Laboratoire d' Astrophysique de Marseille-LAM, Université d' Aix-Marseille and CNRS, UMR7326, 38 rue F. Joliot-Curie, F-13388 Marseille Cedex 13 (France); Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Cormier, D. [Institut für Theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle Str. 2, D-69120 Heidelberg (Germany); Karczewski, O. Ł. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Lebouteiller, V.; Madden, S. C.; Sauvage, M. [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Roussel, H. [Institut d' Astrophysique de Paris, UMR7095 CNRS, Université Pierre and Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France); Spinoglio, L., E-mail: parkintj@mcmaster.ca [Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via Fosso del Cavaliere 100, I-00133 Roma (Italy)

    2013-10-20

    We present Herschel PACS and SPIRE spectroscopy of the most important far-infrared cooling lines in M51, [C II](158 μm), [N II](122 and 205 μm), [O I](63 and 145 μm), and [O III](88 μm). We compare the observed flux of these lines with the predicted flux from a photon-dominated region model to determine characteristics of the cold gas such as density, temperature, and the far-ultraviolet (FUV) radiation field, G{sub 0}, resolving details on physical scales of roughly 600 pc. We find an average [C II]/F{sub TIR} of 4 × 10{sup –3}, in agreement with previous studies of other galaxies. A pixel-by-pixel analysis of four distinct regions of M51 shows a radially decreasing trend in both the FUV radiation field, G{sub 0}, and the hydrogen density, n, peaking in the nucleus of the galaxy, and then falling off out to the arm and interarm regions. We see for the first time that the FUV flux and gas density are similar in the differing environments of the arm and interarm regions, suggesting that the inherent physical properties of the molecular clouds in both regions are essentially the same.

  10. Planck intermediate results: XVII. Emission of dust in the diffuse interstellar medium from the far-infrared to microwave frequencies

    DEFF Research Database (Denmark)

    Bartlett, J.G.; Cardoso, J.-F.; Delabrouille, J.

    2014-01-01

    H-atom. The dust temperature is observed to be anti-correlated with the dust emissivity and opacity. We interpret this result as evidence of dust evolution within the diffuse ISM. The mean dust opacity is measured to be (7.1 ± 0.6) × 10-27 cm2 H-1 × (v/353 GHz) 1.53 ± 0.03for 100 ≤ v ≤ 353 GHz......The dust-Hi correlation is used to characterize the emission properties of dust in the diffuse interstellar medium (ISM) from far infrared wavelengths to microwave frequencies. The field of this investigation encompasses the part of the southern sky best suited to study the cosmic infrared...... and microwave backgrounds. We cross-correlate sky maps from Planck, the Wilkinson Microwave Anisotropy Probe (WMAP), and the diffuse infrared background experiment (DIRBE), at 17 frequencies from 23 to 3000 GHz, with the Parkes survey of the 21 cm line emission of neutral atomic hydrogen, over a contiguous area...

  11. Prognostic Factors Influencing the Patency of Hemodialysis Vascular Access: Literature Review and Novel Therapeutic Modality by Far Infrared Therapy

    Directory of Open Access Journals (Sweden)

    Chih-Ching Lin

    2009-03-01

    Full Text Available In Taiwan, more than 85% of patients with end-stage renal disease undergo maintenance hemodialysis (HD. The native arteriovenous fistula (AVF accounts for a prevalence of more than 80% of the vascular access in our patients. Some mechanical factors may affect the patency of hemodialysis vascular access, such as surgical skill, puncture technique and shear stress on the vascular endothelium. Several medical factors have also been identified to be associated with vascular access prognosis in HD patients, including stasis, hypercoagulability, endothelial cell injury, medications, red cell mass and genotype polymorphisms of transforming growth factor-β1 and methylene tetrahydrofolate reductase. According to our previous study, AVF failure was associated with a longer dinucleotide (GTn repeat (n ≥ 30 in the promoter of the heme oxygenase-1 (HO-1 gene. Our recent study also demonstrated that far-infrared therapy, a noninvasive and convenient therapeutic modality, can improve access flow, inflammatory status and survival of the AVF in HD patients through both its thermal and non-thermal (endothelial-improving, anti-inflammatory, antiproliferative, antioxidative effects by upregulating NF-E2-related factor-2-dependent HO-1 expression, leading to the inhibition of expression of E-selectin, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1.

  12. Post-angioplasty far infrared radiation therapy improves 1-year angioplasty-free hemodialysis access patency of recurrent obstructive lesions.

    Science.gov (United States)

    Lai, C-C; Fang, H-C; Mar, G-Y; Liou, J-C; Tseng, C-J; Liu, C-P

    2013-12-01

    To explore the role of far infrared (FIR) radiation therapy for hemodialysis (HD) access maintenance after percutaneous transluminal angioplasties (PTA). This was a prospective observational study. Eligible patients were those who received repeated PTA with the last PTA successfully performed within 1 week before the study enrollments. Consecutively enrolled patients undergoing successful HD treatments after PTA were randomly assigned to the FIR-radiated group or control group without radiation. FIR-radiated therapy meaning 40-minute radiation at the major lesion site or anastomosed site three times a week was continued until an end-point defined as dysfunction-driven re-PTA or the study end was reached. Of 216 participants analyzed, including 97 with arteriovenous grafts (AVG) (49 FIR-radiated participants and 48 control participants) and 119 with arteriovenous fistulas (AVF) (69 FIR-radiated participants and 50 control participants), the FIR-radiated therapy compared with free-radiated usual therapy significantly enhanced PTA-unassisted patency at 1 year in the AVG subgroup (16.3% vs. 2.1%; p radiated therapy improves PTA-unassisted patency in patients with AVG who have undergone previous PTA. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  13. Submillimeter and far infrared line observations of M17 SW: A clumpy molecular cloud penetrated by UV radiation

    Science.gov (United States)

    Stutzki, J.; Stacey, G. J.; Genzel, R.; Harris, A. I.; Jaffe, d. T.; Lugten, J. B.

    1987-01-01

    Millimeter, submillimeter, and far infrared spectroscopic observations of the M17 SW star formation region are discussed. The results require the molecular cloud near the interface to be clumpy or filamentary. As a consequence, far ultraviolet radiation from the central OB stellar cluster can penetrate into the dense molecular cloud to a depth of several pc, thus creating bright and extended (CII) emission from the photodissociated surfaces of dense atomic and molecular clumps or sheets. The extended (CII) emission throughout the molecular cloud SW of the M17 complex has a level 20 times higher than expected from a single molecular cloud interface exposed to an ultraviolet radiation field typical of the solar neighborhood. This suggests that the molecular cloud as a whole is penetrated by ultraviolet radiation and has a clumpy or filamentary structure. The number of B stars expected to be embedded in the M17 molecular cloud probably can provide the UV radiation necessary for the extended (CII) emission. Alternatively, the UV radiation could be external, if the interstellar radiation in the vicinity of M17 is higher than in the solar neighborhood.

  14. Antibacterial effect of citrus press-cakes dried by high speed and far-infrared radiation drying methods

    Science.gov (United States)

    Samarakoon, Kalpa; Senevirathne, Mahinda; Lee, Won-Woo; Kim, Young-Tae; Kim, Jae-Il; Oh, Myung-Cheol

    2012-01-01

    In this study, the antibacterial effect was evaluated to determine the benefits of high speed drying (HSD) and far-infrared radiation drying (FIR) compared to the freeze drying (FD) method. Citrus press-cakes (CPCs) are released as a by-product in the citrus processing industry. Previous studies have shown that the HSD and FIR drying methods are much more economical for drying time and mass drying than those of FD, even though FD is the most qualified drying method. The disk diffusion assay was conducted, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined with methanol extracts of the dried CPCs against 11 fish and five food-related pathogenic bacteria. The disk diffusion results indicated that the CPCs dried by HSD, FIR, and FD prevented growth of all tested bacteria almost identically. The MIC and MBC results showed a range from 0.5-8.0 mg/mL and 1.0-16.0 mg/mL respectively. Scanning electron microscopy indicated that the extracts changed the morphology of the bacteria cell wall, leading to destruction. These results suggest that CPCs dried by HSD and FIR showed strong antibacterial activity against pathogenic bacteria and are more useful drying methods than that of the classic FD method in CPCs utilization. PMID:22808341

  15. Wave propagation of spectral energy content in a granular chain

    Directory of Open Access Journals (Sweden)

    Shrivastava Rohit Kumar

    2017-01-01

    Full Text Available A mechanical wave is propagation of vibration with transfer of energy and momentum. Understanding the spectral energy characteristics of a propagating wave through disordered granular media can assist in understanding the overall properties of wave propagation through inhomogeneous materials like soil. The study of these properties is aimed at modeling wave propagation for oil, mineral or gas exploration (seismic prospecting or non-destructive testing of the internal structure of solids. The focus is on the total energy content of a pulse propagating through an idealized one-dimensional discrete particle system like a mass disordered granular chain, which allows understanding the energy attenuation due to disorder since it isolates the longitudinal P-wave from shear or rotational modes. It is observed from the signal that stronger disorder leads to faster attenuation of the signal. An ordered granular chain exhibits ballistic propagation of energy whereas, a disordered granular chain exhibits more diffusive like propagation, which eventually becomes localized at long time periods. For obtaining mean-field macroscopic/continuum properties, ensemble averaging has been used, however, such an ensemble averaged spectral energy response does not resolve multiple scattering, leading to loss of information, indicating the need for a different framework for micro-macro averaging.

  16. THE ORIGIN OF THE INFRARED EMISSION IN RADIO GALAXIES. II. ANALYSIS OF MID- TO FAR-INFRARED SPITZER OBSERVATIONS OF THE 2JY SAMPLE

    NARCIS (Netherlands)

    Dicken, D.; Tadhunter, C.; Axon, D.; Morganti, R.; Inskip, K. J.; Holt, J.; Delgado, R. Gonzalez; Groves, B.

    2009-01-01

    We present an analysis of deep mid- to far-infrared (MFIR) Spitzer photometric observations of the southern 2Jy sample of powerful radio sources (0.05

  17. SNSEDextend: SuperNova Spectral Energy Distributions extrapolation toolkit

    Science.gov (United States)

    Pierel, Justin D. R.; Rodney, Steven A.; Avelino, Arturo; Bianco, Federica; Foley, Ryan J.; Friedman, Andrew; Hicken, Malcolm; Hounsell, Rebekah; Jha, Saurabh W.; Kessler, Richard; Kirshner, Robert; Mandel, Kaisey; Narayan, Gautham; Filippenko, Alexei V.; Scolnic, Daniel; Strolger, Louis-Gregory

    2018-05-01

    SNSEDextend extrapolates core-collapse and Type Ia Spectral Energy Distributions (SEDs) into the UV and IR for use in simulations and photometric classifications. The user provides a library of existing SED templates (such as those in the authors' SN SED Repository) along with new photometric constraints in the UV and/or NIR wavelength ranges. The software then extends the existing template SEDs so their colors match the input data at all phases. SNSEDextend can also extend the SALT2 spectral time-series model for Type Ia SN for a "first-order" extrapolation of the SALT2 model components, suitable for use in survey simulations and photometric classification tools; as the code does not do a rigorous re-training of the SALT2 model, the results should not be relied on for precision applications such as light curve fitting for cosmology.

  18. Far infrared spectroscopy of solids. I. Impurity states in Al2O3. II. Electron-hole droplets in Ge

    International Nuclear Information System (INIS)

    Aurbauch, R.L.

    1975-01-01

    Far infrared Fourier transform spectroscopy was used to study the low lying vibronic states of Mn 3+ in Al 2 O 3 and the plasma absorption of electron-hole droplets in Ge. The transmission of Mn-doped samples of Al 2 O 3 was measured in the frequency range from 3 to 30 cm -1 in applied magnetic fields up to 50 kG. Absorption lines were observed due to both ground and excited state transitions. Polarization measurements established that these absorption lines were due to electric dipole transitions. Temperature dependence measurements were used to derive a level diagram for the low lying states of Mn 3+ . A phenomenological model based on an electronic Hamiltonian was developed which successfully describes the data. The empirically determined trigonal field and spin-orbit quenching parameters of this model are 0.7 and 0.1 respectively. This quenching is attributed to the dynamic Jahn--Teller interaction. The plasma absorption of small (α) electron-hole drops in Ge was measured in the frequency range from 30 to 300 cm -1 . The observed absorption is in good agreement with measurements by Vavilov and other workers. A theoretical model which includes both intraband and interband contributions to the dielectric constant in the Rayleigh limit of Mie theory is used to describe the observed lineshape. Measurements of plasma absorption of large (γ) drops in inhomogeneously stressed Ge were made in magnetic fields up to 50 kG. The lineshape at zero applied field was calculated in the large sphere limit of Mie theory including intraband terms and a zero-strain interband term. Qualitative agreement with experiment was obtained. The peak absorption shifted quadratically with applied magnetic field and the total plasma absorption increased. No oscillatory structure was observed in the field-dependence of the total absorption

  19. STAR FORMATION RATES IN RESOLVED GALAXIES: CALIBRATIONS WITH NEAR- AND FAR-INFRARED DATA FOR NGC 5055 AND NGC 6946

    Energy Technology Data Exchange (ETDEWEB)

    Li Yiming; Crocker, Alison F.; Calzetti, Daniela [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Wilson, Christine D. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Kennicutt, Robert C.; Galametz, M. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Murphy, Eric J. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Brandl, Bernhard R.; Groves, B. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Draine, B. T. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Johnson, B. D. [Institut d' Astrophysique de Paris, UMR7095 CNRS, Universite Pierre and Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France); Armus, L. [Spitzer Science Center, California Institute of Technology, MC 314-6, Pasadena, CA 91125 (United States); Gordon, K. D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Croxall, K. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Dale, D. A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Engelbracht, C. W.; Hinz, J. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Hao, C.-N. [Tianjin Astrophysics Center, Tianjin Normal University, Tianjin 300387 (China); Helou, G. [NASA Herschel Science Center, IPAC, California Institute of Technology, Pasadena, CA 91125 (United States); Hunt, L. K., E-mail: yimingl@astro.umass.edu [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); and others

    2013-05-10

    We use the near-infrared Br{gamma} hydrogen recombination line as a reference star formation rate (SFR) indicator to test the validity and establish the calibration of the Herschel/PACS 70 {mu}m emission as a SFR tracer for sub-galactic regions in external galaxies. Br{gamma} offers the double advantage of directly tracing ionizing photons and of being relatively insensitive to the effects of dust attenuation. For our first experiment, we use archival Canada-France-Hawaii Telescope Br{gamma} and Ks images of two nearby galaxies: NGC 5055 and NGC 6946, which are also part of the Herschel program KINGFISH (Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel). We use the extinction corrected Br{gamma} emission to derive the SFR(70) calibration for H II regions in these two galaxies. A comparison of the SFR(70) calibrations at different spatial scales, from 200 pc to the size of the whole galaxy, reveals that about 50% of the total 70 {mu}m emission is due to dust heated by stellar populations that are unrelated to the current star formation. We use a simple model to qualitatively relate the increase of the SFR(70) calibration coefficient with decreasing region size to the star formation timescale. We provide a calibration for an unbiased SFR indicator that combines the observed H{alpha} with the 70 {mu}m emission, also for use in H II regions. We briefly analyze the PACS 100 and 160 {mu}m maps and find that longer wavelengths are not as good SFR indicators as 70 {mu}m, in agreement with previous results. We find that the calibrations show about 50% difference between the two galaxies, possibly due to effects of inclination.

  20. Comparison of laser-based mitigation of fused silica surface damage using mid- versus far-infrared lasers

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S T; Matthews, M J; Elhadj, S; Cooke, D; Guss, G M; Draggoo, V G; Wegner, P J

    2009-12-16

    Laser induced growth of optical damage can limit component lifetime and therefore operating costs of large-aperture fusion-class laser systems. While far-infrared (IR) lasers have been used previously to treat laser damage on fused silica optics and render it benign, little is known about the effectiveness of less-absorbing mid-IR lasers for this purpose. In this study, they quantitatively compare the effectiveness and efficiency of mid-IR (4.6 {micro}m) versus far-IR (10.6 {micro}m) lasers in mitigating damage growth on fused silica surfaces. The non-linear volumetric heating due to mid-IR laser absorption is analyzed by solving the heat equation numerically, taking into account the temperature-dependent absorption coefficient {alpha}(T) at {lambda} = 4.6 {micro}m, while far-IR laser heating is well-described by a linear analytic approximation to the laser-driven temperature rise. In both cases, the predicted results agree well with surface temperature measurements based on infrared radiometry, as well as sub-surface fictive temperature measurements based on confocal Raman microscopy. Damage mitigation efficiency is assessed using a figure of merit (FOM) relating the crack healing depth to laser power required, under minimally-ablative conditions. Based on their FOM, they show that for cracks up to at least 500 {micro}m in depth, mitigation with a 4.6 {micro}m mid-IR laser is more efficient than mitigation with a 10.6 {micro}m far-IR laser. This conclusion is corroborated by direct application of each laser system to the mitigation of pulsed laser-induced damage possessing fractures up to 225 {micro}m in depth.

  1. Human Detection Based on the Generation of a Background Image by Using a Far-Infrared Light Camera

    Directory of Open Access Journals (Sweden)

    Eun Som Jeon

    2015-03-01

    Full Text Available The need for computer vision-based human detection has increased in fields, such as security, intelligent surveillance and monitoring systems. However, performance enhancement of human detection based on visible light cameras is limited, because of factors, such as nonuniform illumination, shadows and low external light in the evening and night. Consequently, human detection based on thermal (far-infrared light cameras has been considered as an alternative. However, its performance is influenced by the factors, such as low image resolution, low contrast and the large noises of thermal images. It is also affected by the high temperature of backgrounds during the day. To solve these problems, we propose a new method for detecting human areas in thermal camera images. Compared to previous works, the proposed research is novel in the following four aspects. One background image is generated by median and average filtering. Additional filtering procedures based on maximum gray level, size filtering and region erasing are applied to remove the human areas from the background image. Secondly, candidate human regions in the input image are located by combining the pixel and edge difference images between the input and background images. The thresholds for the difference images are adaptively determined based on the brightness of the generated background image. Noise components are removed by component labeling, a morphological operation and size filtering. Third, detected areas that may have more than two human regions are merged or separated based on the information in the horizontal and vertical histograms of the detected area. This procedure is adaptively operated based on the brightness of the generated background image. Fourth, a further procedure for the separation and removal of the candidate human regions is performed based on the size and ratio of the height to width information of the candidate regions considering the camera viewing direction

  2. Far infrared conductivity of charge density wave materials and the oxygen isotope effect in high-Tc superconductors

    International Nuclear Information System (INIS)

    Creager, W.N.

    1991-09-01

    The far infrared reflectance and conductivity of (Ta 1-x Nb x Se 4 ) 2 I and TaS 3 have been measured to determine the origin of a huge infrared resonance that dominates the charge density wave (CDW) dynamics along with the pinned acoustic phason mode in the related materials (TaSe 4 ) 2 I and K 0. 3 MoO 3 . The measurements cover frequencies from 3 to 700cm -1 and the temperature range from 15K to 300K. In the niobium-doped alloys (Ta 1-x Nb x Se 4 ) 2 I, the size and frequency of the giant infrared mode remain nearly constant as the impurity concentration x is increased. For TaS 3 , the pinned acoustic phason near 0.5cm -1 dominates var-epsilon(ω) and an additional small mode lies near 9cm -1 . The latter mode is much smaller than the infrared mode in other CDW materials. These results rule out several models of a ''generic infrared mode'' in CDW excitations. They are compared in detail to the predictions of a recent theory attributing the infrared mode to a bound collective mode localized at impurity sites within the crystal. The transmittance of K 0.3 MoO 3 has been measured at 1.2K with a strong dc electric field applied across the crystal. Under these conditions, the charge density wave depins abruptly and carries large currents with near-zero differential resistance. For some samples, the low-frequency transmittance is enhanced slightly when the CDW depins. The magnitude of the oxygen isotope effect in the high-T c superconductor YBa 2 Cu 3 O 7 has been determined by substitution of 18 O for 16 O. A series of cross-exchanges was performed on high-quality polycrystalline specimens to eliminate uncertainties due to sample heat treatments and sample inhomogeneities

  3. Far-infrared radiation inhibits proliferation, migration, and angiogenesis of human umbilical vein endothelial cells by suppressing secretory clusterin levels.

    Science.gov (United States)

    Hwang, Soojin; Lee, Dong-Hoon; Lee, In-Kyu; Park, Young Mi; Jo, Inho

    2014-04-28

    Far-infrared (FIR) radiation is known to lessen the risk of angiogenesis-related diseases including cancer. Because deficiency of secretory clusterin (sCLU) has been reported to inhibit angiogenesis of endothelial cells (EC), we investigated using human umbilical vein EC (HUVEC) whether sCLU mediates the inhibitory effects of FIR radiation. Although FIR radiation ranging 3-25μm wavelength at room temperature for 60min did not alter EC viability, further incubation in the culture incubator (at 37°C under 5% CO2) after radiation significantly inhibited EC proliferation, in vitro migration, and tube formation in a time-dependent manner. Under these conditions, we found decreased sCLU mRNA and protein expression in HUVEC and decreased sCLU protein secreted in culture medium. Expectedly, the replacement of control culture medium with the FIR-irradiated conditioned medium significantly decreased wound closure and tube formation of HUVEC, and vice versa. Furthermore, neutralization of sCLU with anti-sCLU antibody also mimicked all observed inhibitory effects of FIR radiation. Moreover, treatment with recombinant human sCLU protein completely reversed the inhibitory effects of FIR radiation on EC migration and angiogenesis. Lastly, vascular endothelial growth factor also increased sCLU secretion in the culture medium, and wound closure and tube formation of HUVEC, which were significantly reduced by FIR radiation. Our results demonstrate a novel mechanism by which FIR radiation inhibits the proliferation, migration, and angiogenesis of HUVEC, via decreasing sCLU. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  4. STAR FORMATION RATES IN RESOLVED GALAXIES: CALIBRATIONS WITH NEAR- AND FAR-INFRARED DATA FOR NGC 5055 AND NGC 6946

    International Nuclear Information System (INIS)

    Li Yiming; Crocker, Alison F.; Calzetti, Daniela; Wilson, Christine D.; Kennicutt, Robert C.; Galametz, M.; Murphy, Eric J.; Brandl, Bernhard R.; Groves, B.; Draine, B. T.; Johnson, B. D.; Armus, L.; Gordon, K. D.; Croxall, K.; Dale, D. A.; Engelbracht, C. W.; Hinz, J.; Hao, C.-N.; Helou, G.; Hunt, L. K.

    2013-01-01

    We use the near-infrared Brγ hydrogen recombination line as a reference star formation rate (SFR) indicator to test the validity and establish the calibration of the Herschel/PACS 70 μm emission as a SFR tracer for sub-galactic regions in external galaxies. Brγ offers the double advantage of directly tracing ionizing photons and of being relatively insensitive to the effects of dust attenuation. For our first experiment, we use archival Canada-France-Hawaii Telescope Brγ and Ks images of two nearby galaxies: NGC 5055 and NGC 6946, which are also part of the Herschel program KINGFISH (Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel). We use the extinction corrected Brγ emission to derive the SFR(70) calibration for H II regions in these two galaxies. A comparison of the SFR(70) calibrations at different spatial scales, from 200 pc to the size of the whole galaxy, reveals that about 50% of the total 70 μm emission is due to dust heated by stellar populations that are unrelated to the current star formation. We use a simple model to qualitatively relate the increase of the SFR(70) calibration coefficient with decreasing region size to the star formation timescale. We provide a calibration for an unbiased SFR indicator that combines the observed Hα with the 70 μm emission, also for use in H II regions. We briefly analyze the PACS 100 and 160 μm maps and find that longer wavelengths are not as good SFR indicators as 70 μm, in agreement with previous results. We find that the calibrations show about 50% difference between the two galaxies, possibly due to effects of inclination.

  5. Correlation-induced spectral changes and energy conservation

    International Nuclear Information System (INIS)

    Agarwal, G.S.; Wolf, E.

    1996-01-01

    An energy conservation law is derived for fields generated by random, statistically stationary, scalar sources of any state of coherence. It is shown that correlation-induced spectral changes are in strict agreement with this law and that, basic to the understanding of such changes, is a distinction that must be made between the spectrum of a source and the spectrum of the field that the source generates. This distinction, which is obviously relevant for spectroscopy, does not appear to have been previously recognized. copyright 1996 The American Physical Society

  6. Far infrared conductivity of charge density wave materials and the oxygen isotope effect in high-T sub c superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Creager, W.N.

    1991-09-01

    The far infrared reflectance and conductivity of (Ta{sub 1-x}Nb{sub x}Se{sub 4}){sub 2}I and TaS{sub 3} have been measured to determine the origin of a huge infrared resonance that dominates the charge density wave (CDW) dynamics along with the pinned acoustic phason mode in the related materials (TaSe{sub 4}){sub 2}I and K{sub 0. 3}MoO{sub 3}. The measurements cover frequencies from 3 to 700cm{sup {minus}1} and the temperature range from 15K to 300K. In the niobium-doped alloys (Ta{sub 1-x}Nb{sub x}Se{sub 4}){sub 2}I, the size and frequency of the giant infrared mode remain nearly constant as the impurity concentration x is increased. For TaS{sub 3}, the pinned acoustic phason near 0.5cm{sup {minus}1} dominates {var epsilon}({omega}) and an additional small mode lies near 9cm{sup {minus}1}. The latter mode is much smaller than the infrared mode in other CDW materials. These results rule out several models of a generic infrared mode'' in CDW excitations. They are compared in detail to the predictions of a recent theory attributing the infrared mode to a bound collective mode localized at impurity sites within the crystal. The transmittance of K{sub 0.3}MoO{sub 3} has been measured at 1.2K with a strong dc electric field applied across the crystal. Under these conditions, the charge density wave depins abruptly and carries large currents with near-zero differential resistance. For some samples, the low-frequency transmittance is enhanced slightly when the CDW depins. The magnitude of the oxygen isotope effect in the high-{Tc} superconductor YBa{sub 2}Cu{sub 3}O{sub 7} has been determined by substitution of {sup 18}O for {sup 16}O. A series of cross-exchanges was performed on high-quality polycrystalline specimens to eliminate uncertainties due to sample heat treatments and sample inhomogeneities.

  7. Intersubband Rabi oscillations in asymmetric nanoheterostructures: implications for a tunable continuous-wave source of a far-infrared and THz radiation.

    Science.gov (United States)

    Kukushkin, V A

    2012-06-01

    A tunable continuous-wave source of a far-infrared and THz radiation based on a semiconductor nanoheterostructure with asymmetric quantum wells is suggested. It utilizes Rabi oscillations at a transition between quantum well subbands excited by external femtosecond pulses of a mid-infrared electromagnetic field. Due to quantum well broken inversion symmetry the subbands possess different average dipole moments, which enables the creation of polarization at the Rabi frequency as the subband populations change. It is shown that if this polarization is excited so that it is periodic in space, then, though being pulsed, it can produce continuous-wave output radiation. Changing the polarization space period and the time intervals between the exciting pulses, one can tune the frequency of this radiation throughout the far-infrared and THz range. In the present work a concrete multiple quantum well heterostructure design and a scheme of its space-periodic polarization are suggested. It is shown that for existing sources of mid-infrared femtosecond pulses the proposed scheme can provide a continuous-wave output power of order the power of far-infrared and THz quantum cascade lasers. Being added to the possibility of its output frequency tuning, this can make the suggested device attractive for fundamental research and various applications.

  8. Fermi energy 5f spectral weight variation in uranium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Denlinger, J.D.; Clack, J.; Allen, J.W. [Univ. of Michigan, Ann Arbor, MI (United States)] [and others

    1997-04-01

    Uranium materials display a wide range of thermal, electrical and magnetic properties, often exotic. For more than a decade there have been efforts to use photoemission spectroscopy to develop a systematic and unified understanding of the 5f electron states giving rise to this behavior. These efforts have been hampered by a paucity of systems where changes in transport properties are accompanied by substantial spectral changes, so as to allow an attempt to correlate the two kinds of properties within some model. The authors have made resonant photoemission measurements to extract the 5f spectral weight in three systems which show varying degrees of promise of permitting such an attempt, Y{sub 1{minus}x}U{sub x}Pd{sub 3}, U(Pd{sub x}Pt{sub 1{minus}x}){sub 3} and U(Pd{sub x}Cu{sub 1{minus}x}){sub 5}. They have also measured U 4f core level spectra. The 4f spectra can be modeled with some success by the impurity Anderson model (IAM), and the 5f spectra are currently being analyzed in that framework. The IAM characterizes the 5f-electrons of a single site by an f binding energy {epsilon}{sub f}, an f Coulomb interaction and a hybridization V to conduction electrons. Latent in the model are the phenomena of 5f mixed valence and the Kondo effect.

  9. iSEDfit: Bayesian spectral energy distribution modeling of galaxies

    Science.gov (United States)

    Moustakas, John

    2017-08-01

    iSEDfit uses Bayesian inference to extract the physical properties of galaxies from their observed broadband photometric spectral energy distribution (SED). In its default mode, the inputs to iSEDfit are the measured photometry (fluxes and corresponding inverse variances) and a measurement of the galaxy redshift. Alternatively, iSEDfit can be used to estimate photometric redshifts from the input photometry alone. After the priors have been specified, iSEDfit calculates the marginalized posterior probability distributions for the physical parameters of interest, including the stellar mass, star-formation rate, dust content, star formation history, and stellar metallicity. iSEDfit also optionally computes K-corrections and produces multiple "quality assurance" (QA) plots at each stage of the modeling procedure to aid in the interpretation of the prior parameter choices and subsequent fitting results. The software is distributed as part of the impro IDL suite.

  10. Spitzer deep and wide legacy mid- and far-infrared number counts and lower limits of cosmic infrared background

    Science.gov (United States)

    Béthermin, M.; Dole, H.; Beelen, A.; Aussel, H.

    2010-03-01

    Aims: We aim to place stronger lower limits on the cosmic infrared background (CIB) brightness at 24 μm, 70 μm and 160 μm and measure the extragalactic number counts at these wavelengths in a homogeneous way from various surveys. Methods: Using Spitzer legacy data over 53.6 deg2 of various depths, we build catalogs with the same extraction method at each wavelength. Completeness and photometric accuracy are estimated with Monte-Carlo simulations. Number count uncertainties are estimated with a counts-in-cells moment method to take galaxy clustering into account. Furthermore, we use a stacking analysis to estimate number counts of sources not detected at 70 μm and 160 μm. This method is validated by simulations. The integration of the number counts gives new CIB lower limits. Results: Number counts reach 35 μJy, 3.5 mJy and 40 mJy at 24 μm, 70 μm, and 160 μm, respectively. We reach deeper flux densities of 0.38 mJy at 70, and 3.1 at 160 μm with a stacking analysis. We confirm the number count turnover at 24 μm and 70 μm, and observe it for the first time at 160 μm at about 20 mJy, together with a power-law behavior below 10 mJy. These mid- and far-infrared counts: 1) are homogeneously built by combining fields of different depths and sizes, providing a legacy over about three orders of magnitude in flux density; 2) are the deepest to date at 70 μm and 160 μm; 3) agree with previously published results in the common measured flux density range; 4) globally agree with the Lagache et al. (2004) model, except at 160 μm, where the model slightly overestimates the counts around 20 and 200 mJy. Conclusions: These counts are integrated to estimate new CIB firm lower limits of 2.29-0.09+0.09 nW m-2 sr-1, 5.4-0.4+0.4 nW m-2 sr-1, and 8.9-1.1+1.1 nW m-2 sr-1 at 24 μm, 70 μm, and 160 μm, respectively, and extrapolated to give new estimates of the CIB due to galaxies of 2.86-0.16+0.19 nW m-2 sr-1, 6.6-0.6+0.7 nW m-2 sr-1, and 14.6-2.9+7.1 nW m-2 sr-1

  11. Thermoelectrical-electrothermal feedback (te-et f) enhanced performance characteristics of a high temperature superconductor far-infrared bolometer

    International Nuclear Information System (INIS)

    Kaila, M.M.; Russell, G.J.

    2000-01-01

    Full text: It is more than a decade since the discovery of new a High Temperature Superconducting (HTSC) materials. Their adaptation to large scale applications e.g. high magnetic fields, friction-less motors, levitation trains etc., is still long way to go. Small scale applications e.g., far-infrared sensors, has certainly been established as a highly suitable area for immediate economically viable commercial exploitation. The semiconductor counterparts, NT(Neutron Transmutation doped)Ge, CD(Compensation Doped)Si sensors are not only expensive and difficult to manufacture but also require liquid helium refrigeration at mK temperatures to operate. Although the work around the world has centered on photo-electrical bolometers, in our approach we have adopted a much simpler, temperature stable and a better performing photo-thermoelectrical mode of operation. It is well known that the semi-metal BiSb has the highest electronic thermoelectric figure of merit at liquid nitrogen temperatures. One can obtain a value around 1x10 -2 / K by application of a magnetic field to the BiSb leg of a composite. BiSb-HTSC bolometer. We can use this high figure of merit to our advantage in two different modes of operation of the detector. One is the static mode where the thermoelectric power generated across the semi-metal leg (connected in parallel with the HTSC leg) of the bolometer drives the external electronic circuitry. This circuitry can be remotely (no direct electrical contact) coupled to the bolometer e.g. through the primary coil of a SQUID current amplifier, which can be connected in series with the bolometer inside the cryostat, for better noise performance, or outside, for convenience. Second is the heterodyne operation. The external bias is applied in a constant voltage bias mode. The direction of the bias is so chosen that the transient Peltier power generated, from the incident radiation, in the circuit extracts additional heat at the sensitive area of the bolometer

  12. The science case and data processing strategy for the Thinned Aperture Light Collector (TALC): a project for a 20 m far-infrared space telescope

    International Nuclear Information System (INIS)

    Sauvage, Marc; Durand, Gilles A.; Rodriguez, Louis R.; Starck, Jean-Luc; Ronayette, Samuel; Aussel, Herve; Minier, Vincent; Motte, Frederique; Pantin, Eric J.; Sureau, Florent

    2014-01-01

    The future of far-infrared observations rests on our capacity to reach sub-arc-second angular resolution around 100 μm, in order to achieve a significant advance with respect to our current capabilities. Furthermore, by reaching this angular resolution we can bridge the gap between capacities offered by the JWST in the near infrared and those allowed by ALMA in the submillimeter, and thus benefit from similar resolving capacities over the whole wavelength range where interstellar dust radiates and where key atomic and molecular transitions are found. In an accompanying paper, we present a concept of a deployable annular telescope, named TALC for Thinned Aperture Light Collector, reaching 20 m in diameter. Being annular, this telescope features a main beam width equivalent to that of a 27 m telescope, i.e. an angular resolution of 0.92'' at 100 μm. In this paper we focus on the science case of such a telescope as well on the aspects of unconventional data processing that come with this unconventional optical configuration. The principal science cases of TALC revolve around its imaging capacities, that allow resolving the Kuiper belt in extra-solar planetary systems, or the filamentary scale in star forming clouds all the way to the Galactic Center, or the Narrow Line Region in Active Galactic Nuclei of the Local Group, or breaking the confusion limit to resolve the Cosmic Infrared Background. Equipping this telescope with detectors capable of imaging polarimetry offers as well the extremely interesting perspective to study the influence of the magnetic field in structuring the interstellar medium. We will then present simulations of the optical performance of such a telescope. The main feature of an annular telescope is the small amount of energy contained in the main beam, around 30% for the studied configuration, and the presence of bright diffraction rings. Using simulated point spread functions for realistic broad-band filters, we study the observing

  13. MicroRNA-134 Contributes to Glucose-Induced Endothelial Cell Dysfunction and This Effect Can Be Reversed by Far-Infrared Irradiation.

    Directory of Open Access Journals (Sweden)

    Hsei-Wei Wang

    Full Text Available Diabetes mellitus (DM is a metabolic disease that is increasing worldwide. Furthermore, it is associated with the deregulation of vascular-related functions, which can develop into major complications among DM patients. Endothelial colony forming cells (ECFCs have the potential to bring about medical repairs because of their post-natal angiogenic activities; however, such activities are impaired by high glucose- (HG and the DM-associated conditions. Far-infrared radiation (FIR transfers energy as heat that is perceived by the thermoreceptors in human skin. Several studies have revealed that FIR improves vascular endothelial functioning and boost angiogenesis. FIR has been used as anti-inflammatory therapy and as a clinical treatment for peripheral circulation improvement. In addition to vascular repair, there is increasing evidence to show that FIR can be applied to a variety of diseases, including cardiovascular disorders, hypertension and arthritis. Yet mechanism of action of FIR and the biomarkers that indicate FIR effects remain unclear. MicroRNA-134 (miR-134-5p was identified by small RNA sequencing as being increased in high glucose (HG treated dfECFCs (HG-dfECFCs. Highly expressed miR-134 was also validated in dmECFCs by RT-qPCR and it is associated with impaired angiogenic activities of ECFCs. The functioning of ECFCs is improved by FIR treatment and this occurs via a reduction in the level of miR-134 and an increase in the NRIP1 transcript, a direct target of miR-134. Using a mouse ischemic hindlimb model, the recovery of impaired blood flow in the presence of HG-dfECFCs was improved by FIR pretreatment and this enhanced functionality was decreased when there was miR-134 overexpression in the FIR pretreated HG-dfECFCs. In conclusion, our results reveal that the deregulation of miR-134 is involved in angiogenic defects found in DM patients. FIR treatment improves the angiogenic activity of HG-dfECFCs and dmECFCs and FIR has potential as

  14. The complete far-infrared and submillimeter spectrum of the Class 0 protostar Serpens SMM1 obtained with Herschel

    DEFF Research Database (Denmark)

    R. Goicoechea, Javier; Cernicharo, J.; Karska, A.

    2012-01-01

    We present the first complete 55-671 um spectral scan of a low-mass Class 0 protostar (Serpens SMM1) taken with the PACS and SPIRE spectrometers on board Herschel. More than 145 lines have been detected, most of them rotationally excited lines of 12CO (full ladder from J=4-3 to 42-41), H2O, OH, 13...

  15. Simulated galaxy interactions as probes of merger spectral energy distributions

    Energy Technology Data Exchange (ETDEWEB)

    Lanz, Lauranne; Zezas, Andreas; Smith, Howard A.; Ashby, Matthew L. N.; Fazio, Giovanni G.; Hernquist, Lars [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Hayward, Christopher C. [Heidelberger Institut für Theoretische Studien, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg (Germany); Brassington, Nicola, E-mail: llanz@ipac.caltech.edu [School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield, AL10 9AB (United Kingdom)

    2014-04-10

    We present the first systematic comparison of ultraviolet-millimeter spectral energy distributions (SEDs) of observed and simulated interacting galaxies. Our sample is drawn from the Spitzer Interacting Galaxy Survey and probes a range of galaxy interaction parameters. We use 31 galaxies in 14 systems which have been observed with Herschel, Spitzer, GALEX, and 2MASS. We create a suite of GADGET-3 hydrodynamic simulations of isolated and interacting galaxies with stellar masses comparable to those in our sample of interacting galaxies. Photometry for the simulated systems is then calculated with the SUNRISE radiative transfer code for comparison with the observed systems. For most of the observed systems, one or more of the simulated SEDs match reasonably well. The best matches recover the infrared luminosity and the star formation rate of the observed systems, and the more massive systems preferentially match SEDs from simulations of more massive galaxies. The most morphologically distorted systems in our sample are best matched to the simulated SEDs that are close to coalescence, while less evolved systems match well with the SEDs over a wide range of interaction stages, suggesting that an SED alone is insufficient for identifying the interaction stage except during the most active phases in strongly interacting systems. This result is supported by our finding that the SEDs calculated for simulated systems vary little over the interaction sequence.

  16. Selection effects on GRB spectral-energy correlations

    International Nuclear Information System (INIS)

    Nava, Lara; Ghirlanda, Giancarlo; Ghisellini, Gabriele

    2009-01-01

    Instrumental selection effects can act upon the estimates of the peak energy E peak obs , the fluence F and the peak flux P of GRBs. If this were the case, then the correlations involving the corresponding rest frame quantities (i.e. E peak , E obs and the peak luminosity L iso ) would be questioned. We estimated, as a function of E peak obs , the minimum peak flux necessary to trigger a GRB and the minimum fluence a burst must have to determine the value of E peak obs by considering different instruments (BATSE, Swift, BeppoSAX). We find that the latter dominates over the former. We then study the E peak obs -fluence (and flux) correlation in the observer plane. GRBs with redshift show well defined E peak obs -F and E peak obs -P correlations: in this planes the selection effects are present, but do not determine the found correlations. This is not true for Swift GRBs with redshift, for which the spectral analysis threshold does affect their distribution in the observer planes. Extending the sample to GRBs without z, we still find a significant E peak obs -F correlation, although with a larger scatter than that defined by GRBs with redshift. We find that 6% are outliers of the Amati correlation. The E peak obs -P correlation of GRBs with or without redshift is the same and no outlier is found among bursts without redshift.

  17. MgB2 Thin-Film Bolometer for Applications in Far-Infrared Instruments on Future Planetary Missions

    Science.gov (United States)

    Lakew, B.; Aslam, S.; Brasunas, J.; Cao, N.; Costen, N.; La, A.; Stevenson, T.; Waczynski, A.

    2012-01-01

    A SiN membrane based MgB2 thin-film bolometer, with a non-optimized absorber, has been fabricated that shows an electrical noise equivalent power of 256 fW/square root Hz operating at 30 Hz in the 8.5 - 12.35 micron spectral bandpass. This value corresponds to an electrical specific detectivity of 7.6 x 10(exp 10) cm square root Hz/W. The bolometer shows a measured blackbody (optical) specific detectivity of 8.8 x 10(exp 9) cm square root Hz/W, with a responsivity of 701.5 kV/W and a first-order time constant of 5.2 ms. It is predicted that with the inclusion of a gold black absorber that a blackbody specific detectivity of 6.4 x 10(exp 10) cm/square root Hz/W at an operational frequency of 10 Hz, can be realized for integration into future planetary exploration instrumentation where high sensitivity is required in the 17 - 250 micron spectral wavelength range.

  18. DISCOVERY OF TIME VARIATION OF THE INTENSITY OF MOLECULAR LINES IN IRC+10216 IN THE SUBMILLIMETER AND FAR-INFRARED DOMAINS

    Energy Technology Data Exchange (ETDEWEB)

    Cernicharo, J.; Quintana-Lacaci, G.; Agúndez, M.; Velilla-Prieto, L. [Group of Molecular Astrophysics, ICMM, CSIC, C/Sor Juana Inés de La Cruz N3, E-28049 Madrid (Spain); Teyssier, D.; García-Lario, P. [ESA, ESAC, P.O. Box 78, Villanueva de la Cañada, E-28691 Madrid (Spain); Daniel, F. [Univ. Grenoble Alpes, IPAG, F-38000 Grenoble (France); Decin, L. [Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Guélin, M. [Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406 St-Martin d' Hères (France); Encrenaz, P. [LERMA, Observatoire de Paris, 61 Av. de l' Observatoire, F-75014 Paris (France); De Beck, E. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE 439 92 Onsala (Sweden); Barlow, M. J. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Groenewegen, M. A. T. [Koninklijke Sterrenwacht van België, Ringlaan 3, B-1180 Brussels (Belgium); Neufeld, D. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Pearson, J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

    2014-11-20

    We report on the discovery of strong intensity variations in the high rotational lines of abundant molecular species toward the archetypical circumstellar envelope of IRC+10216. The observations have been carried out with the Heterodyne Instrument for the Far-Infrared (HIFI) instrument on board Herschel and with the IRAM30 m telescope. They cover several observing periods spreading over three years. The line intensity variations for molecules produced in the external layers of the envelope most likely result from time variations in the infrared pumping rates. We analyze the main implications this discovery has on the interpretation of molecular line emission in the envelopes of Mira-type stars. Radiative transfer calculations must take into account both the time variability of infrared pumping and the possible variation of the dust and gas temperatures with stellar phase in order to reproduce the observation of molecular lines at different epochs. The effect of gas temperature variations with stellar phase could be particularly important for lines produced in the innermost regions of the envelope. Each layer of the circumstellar envelope sees the stellar light radiation with a different lag time (phase). Our results show that this effect must be included in the models. The submillimeter and far infrared lines of asymptotic giant branch stars can no longer be considered as safe intensity calibrators.

  19. Development of an optical resonator with high-efficient output coupler for the JAERI far-infrared free-electron laser

    International Nuclear Information System (INIS)

    Nagai, Ryoji; Hajima, Ryoichi; Nishimori, Nobuyuki; Sawamura, Masaru; Kikuzawa, Nobuhiro; Shizuma, Toshiyuki; Minehara, Eisuke

    2001-01-01

    An optical resonator with a high-efficient output coupler was developed for the JAERI far-infrared free-electron laser. The optical resonator is symmetrical near-concentric geometry with an insertable scraper output coupler. As a result of the development of the optical resonator, the JAERI-FEL has been successfully, lased with averaged power over 1 kW. Performance of the optical resonator with the output coupler was evaluated at optical wavelength of 22 μm by using an optical mode calculation code. The output coupling and diffractive loss with a dominant eigen-mode of the resonator were calculated using an iterative computation called Fox-Li procedure. An efficiency factor of the optical resonator was introduced for the evaluation of the optical resonator performance. The efficiency factor was derived by the amount of the output coupling and diffractive loss of the optical resonator. It was found that the optical resonator with the insertable scraper coupler was the most suitable to a high-power and high-efficient far-infrared free-electron laser. (author)

  20. Comfort and Functional Properties of Far-Infrared/Anion-Releasing Warp-Knitted Elastic Composite Fabrics Using Bamboo Charcoal, Copper, and Phase Change Materials

    Directory of Open Access Journals (Sweden)

    Ting-Ting Li

    2016-02-01

    Full Text Available Elastic warp-knitted composite fabrics with far-infrared emissivity and an anion-releasing property were prepared using bamboo charcoal (BC, copper (Cu, and phase-change material (PCM. The functional composite fabric, which was composed of self-made complex yarns with various twisting degrees and material composition, were created using a rotor twister and ring-spinning technique. The fabric structure was diversified by the feeding modes of weft yarn into a crochet-knitting machine. The twist number of complex yarns was optimized by tensile tenacity, twist contraction, and hairiness, and analysis showed that twisting at 12 twists per inch produced the highest tensile tenacity and appropriate twist contraction and hairiness. Comfort evaluation showed that the elastic composite fabrics with BC weft yarns exhibited higher water–vapor transmission rate and air permeability, reaching 876 g/m2∙ day and 73.2 cm3/s/cm2, respectively. Three structures of composite fabric with various weft yarns had >0.85 ε far-infrared emissivity and 350–420 counts/cm3 anion amount. The prepared elastic warp-knitted fabrics can provide a comfortable, dry, and breathable environment to the wearer and can thus be applied as health-care textiles in the future.

  1. MgB2 thin-film bolometer for applications in far-infrared instruments on future planetary missions

    International Nuclear Information System (INIS)

    Lakew, B.; Aslam, S.; Brasunas, J.; Cao, N.; Costen, N.; La, A.; Nguyen, L.; Stevenson, T.; Waczynski, A.

    2012-01-01

    A SiN membrane based MgB 2 thin-film bolometer, with a non-optimized absorber, has been fabricated that shows an electrical noise equivalent power of 2.56 × 10 -13 W/√Hz operating at 30 Hz and a responsivity of 702 kV/W. It is predicted that with the inclusion of a gold black absorber that an optical specific detectivity of 8.3 × 10 10 cm/√Hz/W at an operational frequency of 10 Hz, can be realized for integration into future planetary exploration instrumentation where high sensitivity is required in the 17-250 μm spectral wavelength range.

  2. Inverse Compton X-Ray Halos Around High-z Radio Galaxies: A Feedback Mechanism Powered by Far-Infrared Starbursts or the Cosmic Microwave Background?

    Science.gov (United States)

    Small, Ian; Blundell, Katherine M.; Lehmer, B. D.; Alexander, D. M.

    2012-01-01

    We report the detection of extended X-ray emission around two powerful radio galaxies at z approx. 3.6 (4C 03.24 and 4C 19.71) and use these to investigate the origin of extended, inverse Compton (IC) powered X-ray halos at high redshifts. The halos have X-ray luminosities of L(sub X) approx. 3 x 10(exp 44) erg/s and sizes of approx.60 kpc. Their morphologies are broadly similar to the approx.60 kpc long radio lobes around these galaxies suggesting they are formed from IC scattering by relativistic electrons in the radio lobes, of either cosmic microwave background (CMB) photons or far-infrared photons from the dust-obscured starbursts in these galaxies. These observations double the number of z > 3 radio galaxies with X-ray-detected IC halos. We compare the IC X-ray-to-radio luminosity ratios for the two new detections to the two previously detected z approx. 3.8 radio galaxies. Given the similar redshifts, we would expect comparable X-ray IC luminosities if millimeter photons from the CMB are the dominant seed field for the IC emission (assuming all four galaxies have similar ages and jet powers). Instead we see that the two z approx. 3.6 radio galaxies, which are 4 fainter in the far-infrared than those at z 3.8, also have approx.4x fainter X-ray IC emission. Including data for a further six z > or approx. 2 radio sources with detected IC X-ray halos from the literature, we suggest that in the more compact, majority of radio sources, those with lobe sizes < or approx.100-200 kpc, the bulk of the IC emission may be driven by scattering of locally produced far-infrared photons from luminous, dust-obscured starbursts within these galaxies, rather than millimeter photons from the CMB. The resulting X-ray emission appears sufficient to ionize the gas on approx.100-200 kpc scales around these systems and thus helps form the extended, kinematically quiescent Ly(alpha) emission line halos found around some of these systems. The starburst and active galactic nucleus

  3. THE FAR-INFRARED, UV, AND MOLECULAR GAS RELATION IN GALAXIES UP TO z = 2.5

    International Nuclear Information System (INIS)

    Nordon, R.; Lutz, D.; Saintonge, A.; Berta, S.; Wuyts, S.; Förster Schreiber, N. M.; Genzel, R.; Magnelli, B.; Poglitsch, A.; Popesso, P.; Rosario, D.; Sturm, E.; Tacconi, L. J.

    2013-01-01

    We use the infrared excess (IRX) FIR/UV luminosity ratio to study the relation between the effective UV attenuation (A IRX ) and the UV spectral slope (β) in a sample of 450 1 * ) > 9.3. Thus, we are able to study galaxies on and even below the main SFR-stellar mass relation (main sequence). We find that main-sequence galaxies form a tight sequence in the IRX-β plane, which has a flatter slope than commonly used relations. This slope favors a Small-Magellanic-Cloud-like UV extinction curve, though the interpretation is model dependent. The scatter in the A IRX -β plane correlates with the position of the galaxies in the SFR-M * plane. Using a smaller sample of galaxies with CO gas masses, we study the relation between the UV attenuation and the molecular gas content. We find a very tight relation between the scatter in the IRX-β plane and the specific attenuation S A , a quantity that represents the attenuation contributed by the molecular gas mass per young star. S A is sensitive to both the geometrical arrangement of stars and dust and to the compactness of the star-forming regions. We use this empirical relation to derive a method for estimating molecular gas masses using only widely available integrated rest-frame UV and FIR photometry. The method produces gas masses with an accuracy between 0.12 and 0.16 dex in samples of normal galaxies between z ∼ 0 and z ∼ 1.5. Major mergers and submillimeter galaxies follow a different S A relation.

  4. Spectral and dual-energy X-ray imaging for medical applications

    Science.gov (United States)

    Fredenberg, Erik

    2018-01-01

    Spectral imaging is an umbrella term for energy-resolved X-ray imaging in medicine. The technique makes use of the energy dependence of X-ray attenuation to either increase the contrast-to-noise ratio, or to provide quantitative image data and reduce image artefacts by so-called material decomposition. Spectral imaging is not new, but has gained interest in recent years because of rapidly increasing availability of spectral and dual-energy CT and the dawn of energy-resolved photon-counting detectors. This review examines the current technological status of spectral and dual-energy imaging and a number of practical applications of the technology in medicine.

  5. Feasibility study of a microwave or far-infrared scattering experiment to measure small scale turbulence and anomalous transport in J.E.T

    International Nuclear Information System (INIS)

    Koechlin, F.; Olivain, J.; Gresillon, D.; Truc, A.

    1981-03-01

    In the first part, we make a rapid review of what can be expected as low frequency turbulence in J.E.T. This is to define the parameters of the density fluctuations which can be expected. A method to deduce the anomalous transport is described. In the second part, the physical problems of measuring these parameters by microwave or far-infrared scattering are outlined. In the third part, a preliminary study of a microwave scattering experiment at lambda approximately 1.3 mm is made. In the fourth part, a F.I.R. laser experiment at 10.6 μm is also proposed to perform the same measurements. In this last case, an estimation of the thermal nature of the plasma emission could be made, in order to eventually extend the diagnostic to the ion temperature measurement

  6. A method for ultra-short pulse-shape measurements using far infrared coherent radiation from an undulator

    International Nuclear Information System (INIS)

    Geloni, G.; Saldin, E.L.; Schneidmiller, E.A.; Yurkov, M.V.

    2004-01-01

    In this paper, we discuss a method for non-destructive measurements of the longitudinal profile of sub-picosecond electron bunches for X-ray free electron lasers. The method is based on the detection of the coherent synchrotron radiation (CSR) produced by a bunch passing through an undulator. Coherent radiation energy within a central cone turns out to be proportional, per pulse, to the square modulus of the bunch form-factor at the resonant frequency of the fundamental harmonic. An attractive feature of the proposed technique is the absence of any apparent limitation which would distort measurements. Indeed, the radiation process takes place in vacuum and is described by analytical formulae. CSR propagates to the detector placed in vacuum. Since CSR energy is in the range up to a fraction of mJ, a simple bolometer is used to measure the energy with a high accuracy. The proposed technique is very sensitive and it is capable of probing the electron bunches with a resolution down to a few microns

  7. HERSCHEL* FAR-INFRARED SPECTROSCOPY OF THE GALACTIC CENTER. HOT MOLECULAR GAS: SHOCKS VERSUS RADIATION NEAR Sgr A

    Energy Technology Data Exchange (ETDEWEB)

    Goicoechea, Javier R.; Etxaluze, M.; Cernicharo, J.; Bell, T. A. [Departamento de Astrofisica, Centro de Astrobiologia, CSIC-INTA, Carretera de Ajalvir, Km 4, Torrejon de Ardoz, E-28850 Madrid (Spain); Gerin, M.; De Luca, M.; Encrenaz, P. [LERMA, UMR 8112 du CNRS, Observatoire de Paris, Ecole Normale Superieure (France); Neufeld, D. A.; Indriolo, N. [Johns Hopkins University, Baltimore, MD 21218 (United States); Contursi, A. [Max-Planck-Institut fuer extraterrestrische Physik (MPE), Postfach 1312, D-85741 Garching (Germany); Lis, D. C. [California Institute of Technology, Pasadena, CA 91125 (United States); Polehampton, E. T. [RAL Space, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Sonnentrucker, P., E-mail: jr.goicoechea@cab.inta-csic.es [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

    2013-05-20

    We present a {approx}52-671 {mu}m spectral scan toward Sgr A* taken with the PACS and SPIRE spectrometers on board Herschel. The achieved angular resolution allows us to separate, for the first time at far-IR wavelengths, the emission toward the central cavity (gas in the inner central parsec of the galaxy) from that of the surrounding circumnuclear disk. The spectrum toward Sgr A* is dominated by strong [O III], [O I], [C II], [N III], [N II], and [C I] fine-structure lines (in decreasing order of luminosity) arising in gas irradiated by UV photons from the central stellar cluster. In addition, rotationally excited lines of {sup 12}CO (from J = 4-3 to 24-23), {sup 13}CO, H{sub 2}O, OH, H{sub 3}O{sup +}, HCO{sup +}, and HCN, as well as ground-state absorption lines of OH{sup +}, H{sub 2}O{sup +}, H{sub 3}O{sup +}, CH{sup +}, H{sub 2}O, OH, HF, CH, and NH are detected. The excitation of the {sup 12}CO ladder is consistent with a hot isothermal component at T{sub k} {approx_equal} 10{sup 3.1} K and n(H{sub 2}) {approx}< 10{sup 4} cm{sup -3}. It is also consistent with a distribution of temperature components at higher density with most CO at T{sub k} {approx}< 300 K. The detected molecular features suggest that, at present, neither very enhanced X-ray nor cosmic-ray fluxes play a dominant role in the heating of the hot molecular gas. The hot CO component (either the bulk of the CO column or just a small fraction depending on the above scenario) results from a combination of UV- and shock-driven heating. If irradiated dense clumps/clouds do not exist, shocks likely dominate the heating of the hot molecular gas. This is consistent with the high-velocity gas detected toward Sgr A*.

  8. THE ORIGIN OF THE INFRARED EMISSION IN RADIO GALAXIES. II. ANALYSIS OF MID- TO FAR-INFRARED SPITZER OBSERVATIONS OF THE 2JY SAMPLE

    International Nuclear Information System (INIS)

    Dicken, D.; Tadhunter, C.; Axon, D.; Morganti, R.; Inskip, K. J.; Holt, J.; Groves, B.; Delgado, R. Gonzalez

    2009-01-01

    We present an analysis of deep mid- to far-infrared (MFIR) Spitzer photometric observations of the southern 2Jy sample of powerful radio sources (0.05 < z < 0.7), conducting a statistical investigation of the links between radio jet, active galactic nucleus (AGN), starburst activity and MFIR properties. This is part of an ongoing extensive study of powerful radio galaxies that benefits from both complete optical emission line information and a uniquely high detection rate in the far-infrared (far-IR). We find tight correlations between the MFIR and [O III]λ5007 emission luminosities, which are significantly better than those between MFIR and extended radio luminosities, or between radio and [O III] luminosities. Since [O III] is a known indicator of intrinsic AGN power, these correlations confirm AGN illumination of the circumnuclear dust as the primary heating mechanism for the dust producing thermal MFIR emission at both 24 and 70 μm. We demonstrate that AGN heating is energetically feasible, and identify the narrow-line region clouds as the most likely location of the cool, far-IR emitting dust. Starbursts make a major contribution to the heating of the cool dust in only 15%-28% of our targets. We also investigate the orientation dependence of the continuum properties, finding that the broad- and narrow-line objects in our sample with strong emission lines have similar distributions of MFIR luminosities and colors. Therefore our results are entirely consistent with the orientation-based unified schemes for powerful radio galaxies. However, the weak line radio galaxies form a separate class of objects with intrinsically low-luminosity AGNs in which both the optical emission lines and the MFIR continuum are weak.

  9. THE SPECTRAL ENERGY DISTRIBUTIONS AND INFRARED LUMINOSITIES OF z ≈ 2 DUST-OBSCURED GALAXIES FROM Herschel AND Spitzer

    International Nuclear Information System (INIS)

    Melbourne, J.; Soifer, B. T.; Desai, Vandana; Armus, Lee; Pope, Alexandra; Alberts, Stacey; Dey, Arjun; Jannuzi, B. T.; Bussmann, R. S.

    2012-01-01

    Dust-obscured galaxies (DOGs) are a subset of high-redshift (z ≈ 2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L IR > 10 12 L ☉ ). We present new far-infrared photometry, at 250, 350, and 500 μm (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 10 11.6 L ☉ IR (8-1000 μm) 13.6 L ☉ . 90% of the Herschel-detected DOGs in this sample are ULIRGs and 30% have L IR > 10 13 L ☉ . The rest-frame near-IR (1-3 μm) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths. DOGs with 'power-law' SEDs in the rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to the QSO-like local ULIRG, Mrk 231. DOGs with a stellar 'bump' in their rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to local star-bursting ULIRGs like NGC 6240. None show 250/24 μm flux density ratios similar to extreme local ULIRG, Arp 220; though three show 350/24 μm flux density ratios similar to Arp 220. For the Herschel-detected DOGs, accurate estimates (within ∼25%) of total IR luminosity can be predicted from their rest-frame mid-IR data alone (e.g., from Spitzer observed-frame 24 μm luminosities). Herschel-detected DOGs tend to have a high ratio of infrared luminosity to rest-frame 8 μm luminosity (the IR8 = L IR (8-1000 μm)/νL ν (8 μm) parameter of Elbaz et al.). Instead of lying on the z = 1-2 'infrared main sequence' of star-forming galaxies (like typical LIRGs and ULIRGs at those epochs) the DOGs, especially large fractions of the bump sources, tend to lie in the starburst sequence. While, Herschel-detected DOGs are similar to scaled up

  10. Spectrally and Energy Efficient OFDM (SEE-OFDM) for Intensity Modulated Optical Wireless Systems

    OpenAIRE

    Lam, Emily; Wilson, Sarah Kate; Elgala, Hany; Little, Thomas D. C.

    2015-01-01

    Spectrally and energy efficient orthogonal frequency division multiplexing (SEE-OFDM) is an optical OFDM technique based on combining multiple asymmetrically clipped optical OFDM (ACO-OFDM) signals into one OFDM signal. By summing different components together, SEE-OFDM can achieve the same spectral efficiency as DC-biased optical OFDM (DCO-OFDM) without an energy-inefficient DC-bias. This paper introduces multiple methods for decoding a SEE-OFDM symbol and shows that an iterative decoder wit...

  11. Electron-energy-loss spectral library and its application to materials science

    Energy Technology Data Exchange (ETDEWEB)

    Zaluzec, N.J.

    1983-09-01

    An electron energy loss spectral library can be an invaluable tool in materials research from a fundamental as well as a practical standpoint. Although it will not alleviate all the complications associated with quantification, this type of library can help to elucidate details of spectral profiles previously found intractable. This work was supported by the US Department of Energy. The author also wishes to express his gratitude to the organizing committee for partial financial support provided to attend this meeting.

  12. Image enhancement by spectral-error correction for dual-energy computed tomography.

    Science.gov (United States)

    Park, Kyung-Kook; Oh, Chang-Hyun; Akay, Metin

    2011-01-01

    Dual-energy CT (DECT) was reintroduced recently to use the additional spectral information of X-ray attenuation and aims for accurate density measurement and material differentiation. However, the spectral information lies in the difference between low and high energy images or measurements, so that it is difficult to acquire accurate spectral information due to amplification of high pixel noise in the resulting difference image. In this work, an image enhancement technique for DECT is proposed, based on the fact that the attenuation of a higher density material decreases more rapidly as X-ray energy increases. We define as spectral error the case when a pixel pair of low and high energy images deviates far from the expected attenuation trend. After analyzing the spectral-error sources of DECT images, we propose a DECT image enhancement method, which consists of three steps: water-reference offset correction, spectral-error correction, and anti-correlated noise reduction. It is the main idea of this work that makes spectral errors distributed like random noise over the true attenuation and suppressed by the well-known anti-correlated noise reduction. The proposed method suppressed noise of liver lesions and improved contrast between liver lesions and liver parenchyma in DECT contrast-enhanced abdominal images and their two-material decomposition.

  13. INVERSE COMPTON X-RAY HALOS AROUND HIGH-z RADIO GALAXIES: A FEEDBACK MECHANISM POWERED BY FAR-INFRARED STARBURSTS OR THE COSMIC MICROWAVE BACKGROUND?

    Energy Technology Data Exchange (ETDEWEB)

    Smail, Ian [Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE (United Kingdom); Blundell, Katherine M. [Department of Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Lehmer, B. D. [Department of Physics and Astronomy, The Johns Hopkins University, Homewood Campus, Baltimore, MD 21218 (United States); Alexander, D. M. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)

    2012-12-01

    We report the detection of extended X-ray emission around two powerful radio galaxies at z {approx} 3.6 (4C 03.24 and 4C 19.71) and use these to investigate the origin of extended, inverse Compton (IC) powered X-ray halos at high redshifts. The halos have X-ray luminosities of L {sub X} {approx} 3 Multiplication-Sign 10{sup 44} erg s{sup -1} and sizes of {approx}60 kpc. Their morphologies are broadly similar to the {approx}60 kpc long radio lobes around these galaxies suggesting they are formed from IC scattering by relativistic electrons in the radio lobes, of either cosmic microwave background (CMB) photons or far-infrared photons from the dust-obscured starbursts in these galaxies. These observations double the number of z > 3 radio galaxies with X-ray-detected IC halos. We compare the IC X-ray-to-radio luminosity ratios for the two new detections to the two previously detected z {approx} 3.8 radio galaxies. Given the similar redshifts, we would expect comparable X-ray IC luminosities if millimeter photons from the CMB are the dominant seed field for the IC emission (assuming all four galaxies have similar ages and jet powers). Instead we see that the two z {approx} 3.6 radio galaxies, which are {approx}4 Multiplication-Sign fainter in the far-infrared than those at z {approx} 3.8, also have {approx}4 Multiplication-Sign fainter X-ray IC emission. Including data for a further six z {approx}> 2 radio sources with detected IC X-ray halos from the literature, we suggest that in the more compact, majority of radio sources, those with lobe sizes {approx}<100-200 kpc, the bulk of the IC emission may be driven by scattering of locally produced far-infrared photons from luminous, dust-obscured starbursts within these galaxies, rather than millimeter photons from the CMB. The resulting X-ray emission appears sufficient to ionize the gas on {approx}100-200 kpc scales around these systems and thus helps form the extended, kinematically quiescent Ly{alpha} emission line

  14. Far infrared fusion plasma diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Luhmann, N.C. Jr.; Peebles, W.A.

    1990-01-01

    Over the last several years, reflectometry has grown in importance as a diagnostic for both steady-state density Profiles as well as for the investigation of density fluctuations and turbulence. As a diagnostic for density profile measurement, it is generally believed to be well understood in the tokamak environment. However, its use as a fluctuation diagnostic is hampered by a lack of quantitative experimental understanding of its wavenumber sensitivity and spatial resolution. Several researchers, have theoretically investigated these questions. However, prior to the UCLA laboratory investigation, no group has experimentally investigated these questions. Because of the reflectometer's importance to the world effort in understanding plasma turbulence and transport, UCLA has, over the last year, made its primary Task IIIA effort the resolution of these questions. UCLA has taken the lead in a quantitative experimental understanding of reflectometer data as applied to the measurement of density fluctuations. In addition to this, work has proceeded on the design, construction, and installation of a reflectometer system on UCLA's CCT tokamak. This effort will allow a comparison between the improved confinement regimes (H-mode) observed on both the DIII-D and CCT machines with the goal of achieving a physics understanding of the phenomena. Preliminary investigation of a new diagnostic technique to measure density profiles as a function of time has been initiated at UCLA. The technique promises to be a valuable addition to the range of available plasma diagnostics. Work on advanced holographic reflectometry technique as applied to fluctuation diagnostics has awaited a better understanding of the reflectometer signal itself as discussed above. Efforts to ensure the transfer of the diagnostic developments have continued with particular attention devoted to the preliminary design of a multichannel FIR interferometer for MST.

  15. Coherent tunable far infrared radiation

    Science.gov (United States)

    Jennings, D. A.

    1989-01-01

    Tunable, CW, FIR radiation has been generated by nonlinear mixing of radiation from two CO2 lasers in a metal-insulator-metal (MIM) diode. The FIR difference-frequency power was radiated from the MIM diode antenna to a calibrated InSb bolometer. FIR power of 200 nW was generated by 250 mW from each of the CO2 lasers. Using the combination of lines from a waveguide CO2 laser, with its larger tuning range, with lines from CO2, N2O, and CO2-isotope lasers promises complete coverage of the entire FIR band with stepwise-tunable CW radiation.

  16. Energy Efficient LED Spectrally Matched Smart Lighting, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Innovative Imaging and Research and the University of Houston Clear Lake have teamed to develop a widely extensible, affordable, energy efficient, smart lighting...

  17. A mass and energy conserving spectral element atmospheric dynamical core on the cubed-sphere grid

    International Nuclear Information System (INIS)

    Taylor, M A; Edwards, J; Thomas, S; Nair, R

    2007-01-01

    We present results from a conservative formulation of the spectral element method applied to global atmospheric circulation modeling. Exact local conservation of both mass and energy is obtained via a new compatible formulation of the spectral element method. Compatibility insures that the key integral property of the divergence and gradient operators required to show conservation also hold in discrete form. The spectral element method is used on a cubed-sphere grid to discretize the horizontal directions on the sphere. It can be coupled to any conservative vertical/radial discretization. The accuracy and conservation properties of the method are illustrated using a baroclinic instability test case

  18. Guided-wave approaches to spectrally selective energy absorption

    Science.gov (United States)

    Stegeman, G. I.; Burke, J. J.

    1987-01-01

    Results of experiments designed to demonstrate spectrally selective absorption in dielectric waveguides on semiconductor substrates are reported. These experiments were conducted with three waveguides formed by sputtering films of PSK2 glass onto silicon-oxide layers grown on silicon substrates. The three waveguide samples were studied at 633 and 532 nm. The samples differed only in the thickness of the silicon-oxide layer, specifically 256 nm, 506 nm, and 740 nm. Agreement between theoretical predictions and measurements of propagation constants (mode angles) of the six or seven modes supported by these samples was excellent. However, the loss measurements were inconclusive because of high scattering losses in the structures fabricated (in excess of 10 dB/cm). Theoretical calculations indicated that the power distribution among all the modes supported by these structures will reach its steady state value after a propagation length of only 1 mm. Accordingly, the measured loss rates were found to be almost independent of which mode was initially excited. The excellent agreement between theory and experiment leads to the conclusion that low loss waveguides confirm the predicted loss rates.

  19. Far-infrared properties of sol-gel derived PbZr0.52Ti0.48O3 thin films on Pt-coated substrates

    International Nuclear Information System (INIS)

    Kafadaryan, E A; Hovsepyan, R K; Khachaturova, A A; Aghamalyan, N R; Shirinyan, G O; Manukyan, A L; Vardanyan, R S; Hayrapetyan, A G; Grigoryan, S G; Vardanyan, E S

    2003-01-01

    Polycrystalline tetragonal PbZr 0.52 Ti 0.48 O 3 (PZT) thin films have been deposited on the nickel and (111) platinum coated (110) sapphire substrates by the sol-gel method. Optical properties of the PZT thin films were studied using far-infrared reflectivity spectroscopy in the 200-10 000 cm -1 frequency range at 300 K. The frequency dependence of the optical characteristics (σ, ε, -Im ε -1 ) of the films were calculated by the Kramers-Kronig transformation of the reflectivity spectra and analysed by the Drude-Lorentz model. The frequency dependence of the optical conductivity, σ(ω), of the PZT films deposited on platinum coated sapphire is well described by the free-carrier term and an overdamped mid-infrared component. Sapphire/Pt/PZT structures reveal semiconductor properties (effective carrier concentration N/m* is up to 10 20 cm -3 , plasma minimum is located near 3000 cm -1 ). This effect can be related to the favourable influence of the platinum electrode on the charge carrier density at Pt/PZT contact and formation of the interfacial conductive layer

  20. Far-Infrared Based Pedestrian Detection for Driver-Assistance Systems Based on Candidate Filters, Gradient-Based Feature and Multi-Frame Approval Matching.

    Science.gov (United States)

    Wang, Guohua; Liu, Qiong

    2015-12-21

    Far-infrared pedestrian detection approaches for advanced driver-assistance systems based on high-dimensional features fail to simultaneously achieve robust and real-time detection. We propose a robust and real-time pedestrian detection system characterized by novel candidate filters, novel pedestrian features and multi-frame approval matching in a coarse-to-fine fashion. Firstly, we design two filters based on the pedestrians' head and the road to select the candidates after applying a pedestrian segmentation algorithm to reduce false alarms. Secondly, we propose a novel feature encapsulating both the relationship of oriented gradient distribution and the code of oriented gradient to deal with the enormous variance in pedestrians' size and appearance. Thirdly, we introduce a multi-frame approval matching approach utilizing the spatiotemporal continuity of pedestrians to increase the detection rate. Large-scale experiments indicate that the system works in real time and the accuracy has improved about 9% compared with approaches based on high-dimensional features only.

  1. In Vitro and In Vivo Studies of the Biological Effects of Bioceramic (a Material of Emitting High Performance Far-Infrared Ray) Irradiation.

    Science.gov (United States)

    Leung, Ting-Kai

    2015-06-30

    Bioceramic is a material that emits high performance far-infrared ray, and possess physical, chemical and biological characteristics on irradiation of water, particularly to in reducing the size of water clusters, weakening of the hydrogen bonds of water molecules and other effects on physical and chemical properties of water. In this review paper, we summarized the in vivo and in vitro biological effects of Biocermaic, and included previous published data on nitric oxide, calmodulin induction on cells, effects of bioceramic on intracellular heat shock protein and intracellular nitric oxide contents of melanoma cells, antioxidant effects of Bioceramic on cells and plants under H₂O₂-mediated oxidative stress, effects on anti-oxidative stress of myoblast cells and on preventing fatigue of amphibian skeletal muscle during exercise, anti-inflammatory and pain relief mechanism, effects on the chondrosarcoma cell line with prostaglandin E2 production, effects on the rabbit with inflammatory arthritis by injection of lipopolysaccharides under monitoring by positron emission tomography scan, effects on psychological stress-conditioned elevated heart rate, blood pressure and oxidative stress-suppressed cardiac contractility, and protective effects of non-ionized radiation against oxidative stress on human breast epithelial cell. We anticipate that the present work will benefit medical applications.

  2. The solid molecular hydrogens in the ordered state as function of density and ortho-para concentration: a far infrared study

    International Nuclear Information System (INIS)

    Jochemsen, R.

    1978-01-01

    In this thesis, the results of far infrared absorption experiments on solid molecular hydrogen and deuterium are presented. In Chapter I an introduction to the properties of solid molecular hydrogens in given. The experimental system used for the high pressure infrared measurements and the data handling procedures are discussed in Chapter II. The theory of infrared absorption and the averaging of the dipole moment over the motion of the molecules is contained in Chapter III. In this chapter a general sum rule for the integrated absorption is derived. The remaining chapters present the results of the measurements and the discussion. In Chapter IV the author concentrates on the phonon frequencies as a function of ortho-para concentration and density, while in Chapter V measuremtns of phonon lineshape and integrated absorption intensities are presented. Finally, in Chapter VI, a study is given of the phase transition in solid hydrogen and deuterium. This study provides accurate values for the transition temperature as a function of density (in deuterium) and as a function of ortho-para concentration (in hydrogen) as well as the dependence of the order parameter on the temperature and the ortho-para concentration. (Auth.)

  3. Far-Infrared Based Pedestrian Detection for Driver-Assistance Systems Based on Candidate Filters, Gradient-Based Feature and Multi-Frame Approval Matching

    Directory of Open Access Journals (Sweden)

    Guohua Wang

    2015-12-01

    Full Text Available Far-infrared pedestrian detection approaches for advanced driver-assistance systems based on high-dimensional features fail to simultaneously achieve robust and real-time detection. We propose a robust and real-time pedestrian detection system characterized by novel candidate filters, novel pedestrian features and multi-frame approval matching in a coarse-to-fine fashion. Firstly, we design two filters based on the pedestrians’ head and the road to select the candidates after applying a pedestrian segmentation algorithm to reduce false alarms. Secondly, we propose a novel feature encapsulating both the relationship of oriented gradient distribution and the code of oriented gradient to deal with the enormous variance in pedestrians’ size and appearance. Thirdly, we introduce a multi-frame approval matching approach utilizing the spatiotemporal continuity of pedestrians to increase the detection rate. Large-scale experiments indicate that the system works in real time and the accuracy has improved about 9% compared with approaches based on high-dimensional features only.

  4. Far-infrared spectroscopy in ordered and disordered BaMg1/3Nb2/3O3 microwave ceramics

    Science.gov (United States)

    Dias, Anderson; Moreira, Roberto Luiz

    2003-09-01

    Ba(Mg1/3Nb2/3)O3 ceramics with suitable microwave dielectric properties for application in wireless communications and information access technologies were studied by far-infrared spectroscopy. Samples with different B-site ordering degrees, obtained by hydrothermal synthesis followed by sintering at various temperatures, were employed in this investigation. The sixteen infrared modes predicted by factor-group analysis were observed and adjusted according to a four-parameter semiquantum model. The dispersion parameters were determined in order to calculate the real part of the dielectric permittivity and the quality factors associated with the dielectric losses in the microwave region. The materials exhibited increasing ɛ0 and Q values up to 1100 °C, increasing more substantially when the temperature attained 1300 °C. The B-site ordering played an important role on this behavior along with the microstructural evolution above 1100 °C (grain growth), which also increased the phonon lifetime and contributed to the Q improvement. Kramers-Kronig analyses were carried out in all experimental data and the contributions of the main optical polar modes to the dielectric and microwave properties were carefully analyzed in order to identify and attribute the Ba-BO3 external mode, the inner modes related to the O-Mg-O and O-Nb-O bending vibrations, and the stretching modes of each MgO6 and NbO6 octahedron.

  5. A Parallel-Arm Randomized Controlled Trial to Assess the Effects of a Far-Infrared-Emitting Collar on Neck Disorder

    Directory of Open Access Journals (Sweden)

    Yung-Sheng Lin

    2015-09-01

    Full Text Available The purpose of this study is to assess the beneficial effects of a far-infrared-emitting collar (FIRC on the management of neck disorders. A neck disorder is generalized as neck muscle pain and its relative mental disorders because the etiologies of the neck’s multidimensional syndrome are either muscle impairment or psychiatric distress. This is the first study to determine the efficacy of a FIRC by evaluating objective physical evidence and psychometric self-reports using a parallel-arm randomized sham-controlled and single-blinded design. In this trial, 60 participants with neck disorders were observed at baseline and post-intervention. Compared to the placebo group after a 30-min intervention, the FIRC demonstrated a statistically significant biological effect in elevating skin temperature and promoting blood circulation with p-values 0.003 and 0.020, respectively. In addition, FIRC application significantly reduced neck muscle tension, relieved pain, ameliorated fatigue, improved depression, and decreased anxiety. The FIRC could therefore be a potential treatment for neck disorders.

  6. Far-infrared radiation protects viability in a cell model of Spinocerebellar Ataxia by preventing polyQ protein accumulation and improving mitochondrial function.

    Science.gov (United States)

    Chang, Jui-Chih; Wu, Shey-Lin; Hoel, Fredrik; Cheng, Yu-Shan; Liu, Ko-Hung; Hsieh, Mingli; Hoel, August; Tronstad, Karl Johan; Yan, Kuo-Chia; Hsieh, Ching-Liang; Lin, Wei-Yong; Kuo, Shou-Jen; Su, Shih-Li; Liu, Chin-San

    2016-07-29

    Far infrared radiation (FIR) is currently investigated as a potential therapeutic strategy in various diseases though the mechanism is unknown. Presently, we tested if FIR mediates beneficial effects in a cell model of the neurodegenerative disease spinocerebellar ataxia type 3 (SCA3). SCA3 is caused by a mutation leading to an abnormal polyglutamine expansion (PolyQ) in ataxin-3 protein. The consequent aggregation of mutant ataxin-3 results in disruption of vital cell functions. In this study, neuroblastoma cells (SK-N-SH) was transduced to express either non-pathogenic ataxin-3-26Q or pathogenic ataxin-3-78Q proteins. The cells expressing ataxin-3-78Q demonstrated decreased viability, and increased sensitivity to metabolic stress in the presence rotenone, an inhibitor of mitochondrial respiration. FIR exposure was found to protect against these effects. Moreover, FIR improved mitochondrial respiratory function, which was significantly compromised in ataxin-3-78Q and ataxin-3-26Q expressing cells. This was accompanied by decreased levels of mitochondrial fragmentation in FIR treated cells, as observed by fluorescence microscopy and protein expression analysis. Finally, the expression profile LC3-II, Beclin-1 and p62 suggested that FIR prevent the autophagy inhibiting effects observed in ataxin-3-78Q expressing cells. In summary, our results suggest that FIR have rescuing effects in cells expressing mutated pathogenic ataxin-3, through recovery of mitochondrial function and autophagy.

  7. Far infrared near normal specular reflectivity of Nix(SiO2)1-x (x = 1.0, 0.84, 0.75, 0.61, 0.54, 0.28) granular films

    KAUST Repository

    Massa, Né stor E.; Denardin, Juliano C.; Socolovsky, Leandro M.; Knobel, Marcelo; De La Cruz, Fernando Pablo; Zhang, Xixiang

    2010-01-01

    of transition metal granular films with different metal fractions against what is known for conducting oxides. Films for Nix(SiO2)1-x (x = 1.0, 0.84, 0.75, 0.61, 0.54, 0.28) were studied by temperature dependent far infrared measurements. While for pure Ni

  8. Spectral and energy efficiency analysis of uplink heterogeneous networks with small-cells on edge

    KAUST Repository

    Shakir, Muhammad Zeeshan

    2014-12-01

    This paper presents a tractable mathematical framework to analyze the spectral and energy efficiency of an operator initiated deployment of the small-cells (e.g., femtocells) where the small-cell base stations are deliberately positioned around the edge of the macrocell. The considered deployment facilitates the cell-edge mobile users in terms of their coverage, spectral, and energy efficiency and is referred to as cell-on-edge (COE) configuration. The reduction in energy consumption is achieved by considering fast power control where the mobile users transmit with adaptive power to compensate the path loss, shadowing and fading. In particular, we develop a moment generating function (MGF) based approach to derive analytical bounds on the area spectral efficiency and exact expressions for the energy efficiency of the mobile users in the considered COE configuration over generalized-K fading channels. Besides the COE configuration, the derived bounds are also shown to be useful in evaluating the performance of random small-cell deployments, e.g., uniformly distributed small-cells. Simulation results are presented to demonstrate the improvements in spectral and energy efficiency of the COE configuration with respect to macro-only networks and other unplanned deployment strategies. © 2014 Elsevier B.V. All rights reserved.

  9. Effects of whole-body cryotherapy vs. far-infrared vs. passive modalities on recovery from exercise-induced muscle damage in highly-trained runners.

    Directory of Open Access Journals (Sweden)

    Christophe Hausswirth

    Full Text Available Enhanced recovery following physical activity and exercise-induced muscle damage (EIMD has become a priority for athletes. Consequently, a number of post-exercise recovery strategies are used, often without scientific evidence of their benefits. Within this framework, the purpose of this study was to test the efficacy of whole body cryotherapy (WBC, far infrared (FIR or passive (PAS modalities in hastening muscular recovery within the 48 hours after a simulated trail running race. In 3 non-adjoining weeks, 9 well-trained runners performed 3 repetitions of a simulated trail run on a motorized treadmill, designed to induce muscle damage. Immediately (post, post 24 h, and post 48 h after exercise, all participants tested three different recovery modalities (WBC, FIR, PAS in a random order over the three separate weeks. Markers of muscle damage (maximal isometric muscle strength, plasma creatine kinase [CK] activity and perceived sensations [i.e. pain, tiredness, well-being] were recorded before, immediately after (post, post 1 h, post 24 h, and post 48 h after exercise. In all testing sessions, the simulated 48 min trail run induced a similar, significant amount of muscle damage. Maximal muscle strength and perceived sensations were recovered after the first WBC session (post 1 h, while recovery took 24 h with FIR, and was not attained through the PAS recovery modality. No differences in plasma CK activity were recorded between conditions. Three WBC sessions performed within the 48 hours after a damaging running exercise accelerate recovery from EIMD to a greater extent than FIR or PAS modalities.

  10. High-resolution far-infrared synchrotron FTIR spectrum of the ν12 band of formamide-d1 (DCONH2)

    Science.gov (United States)

    Tan, T. L.; Wu, Q. Y.; Ng, L. L.; Appadoo, Dominique R. T.; McNaughton, Don

    2018-05-01

    The spectrum of the ν12 band of formamide-d1 (DCONH2) was recorded using a synchrotron Fourier transform infrared (FTIR) spectrometer coupled to the Australian Synchrotron THz/Far-IR beamline, with an unapodized resolution of 0.00096 cm-1 in the 350-210 cm-1 region. For the first time, rovibrational constants up to five quartic and two sextic terms were derived for the v12 = 1 state through the fitting of a total of 2072 far-infrared transitions using Watson's A-reduced Hamiltonian in the Ir representation with a root-mean-square (rms) deviation of 0.000073 cm-1. The band centre of the ν12 band of DCONH2 was found to be 289.3327553(47) cm-1 although the experimental uncertainty was limited to ±0.0002 cm-1. Ground state rovibrational constants of DCONH2 up to five quartic and two sextic constants were derived from a fit of 847 ground state combination differences (GSCDs) obtained from the infrared transitions of the ν12 band, together with 6 previously reported microwave transitions, with a rms deviation of 0.000108 cm-1. The ground state rotational constants (A, B, and C) of DCONH2 were improved while the ground state centrifugal distortion constants were accurately obtained for the first time. The uncertainty of the measured infrared lines was estimated to be ±0.0002 cm-1. From the ground state rotational constants, the inertial defect of DCONH2 was calculated to be 0.0169412(11) uÅ2.

  11. Effects of Whole-Body Cryotherapy vs. Far-Infrared vs. Passive Modalities on Recovery from Exercise-Induced Muscle Damage in Highly-Trained Runners

    Science.gov (United States)

    Hausswirth, Christophe; Louis, Julien; Bieuzen, François; Pournot, Hervé; Fournier, Jean; Filliard, Jean-Robert; Brisswalter, Jeanick

    2011-01-01

    Enhanced recovery following physical activity and exercise-induced muscle damage (EIMD) has become a priority for athletes. Consequently, a number of post-exercise recovery strategies are used, often without scientific evidence of their benefits. Within this framework, the purpose of this study was to test the efficacy of whole body cryotherapy (WBC), far infrared (FIR) or passive (PAS) modalities in hastening muscular recovery within the 48 hours after a simulated trail running race. In 3 non-adjoining weeks, 9 well-trained runners performed 3 repetitions of a simulated trail run on a motorized treadmill, designed to induce muscle damage. Immediately (post), post 24 h, and post 48 h after exercise, all participants tested three different recovery modalities (WBC, FIR, PAS) in a random order over the three separate weeks. Markers of muscle damage (maximal isometric muscle strength, plasma creatine kinase [CK] activity and perceived sensations [i.e. pain, tiredness, well-being]) were recorded before, immediately after (post), post 1 h, post 24 h, and post 48 h after exercise. In all testing sessions, the simulated 48 min trail run induced a similar, significant amount of muscle damage. Maximal muscle strength and perceived sensations were recovered after the first WBC session (post 1 h), while recovery took 24 h with FIR, and was not attained through the PAS recovery modality. No differences in plasma CK activity were recorded between conditions. Three WBC sessions performed within the 48 hours after a damaging running exercise accelerate recovery from EIMD to a greater extent than FIR or PAS modalities. PMID:22163272

  12. Pedestrian Detection Based on Adaptive Selection of Visible Light or Far-Infrared Light Camera Image by Fuzzy Inference System and Convolutional Neural Network-Based Verification.

    Science.gov (United States)

    Kang, Jin Kyu; Hong, Hyung Gil; Park, Kang Ryoung

    2017-07-08

    A number of studies have been conducted to enhance the pedestrian detection accuracy of intelligent surveillance systems. However, detecting pedestrians under outdoor conditions is a challenging problem due to the varying lighting, shadows, and occlusions. In recent times, a growing number of studies have been performed on visible light camera-based pedestrian detection systems using a convolutional neural network (CNN) in order to make the pedestrian detection process more resilient to such conditions. However, visible light cameras still cannot detect pedestrians during nighttime, and are easily affected by shadows and lighting. There are many studies on CNN-based pedestrian detection through the use of far-infrared (FIR) light cameras (i.e., thermal cameras) to address such difficulties. However, when the solar radiation increases and the background temperature reaches the same level as the body temperature, it remains difficult for the FIR light camera to detect pedestrians due to the insignificant difference between the pedestrian and non-pedestrian features within the images. Researchers have been trying to solve this issue by inputting both the visible light and the FIR camera images into the CNN as the input. This, however, takes a longer time to process, and makes the system structure more complex as the CNN needs to process both camera images. This research adaptively selects a more appropriate candidate between two pedestrian images from visible light and FIR cameras based on a fuzzy inference system (FIS), and the selected candidate is verified with a CNN. Three types of databases were tested, taking into account various environmental factors using visible light and FIR cameras. The results showed that the proposed method performs better than the previously reported methods.

  13. Association of Far-Infrared Radiation Therapy and Ankle-Brachial Index of Patients on Hemodialysis with Peripheral Artery Occlusive Disease.

    Science.gov (United States)

    Chen, Szu-Chia; Lee, Mei-Yueh; Huang, Jiun-Chi; Kuo, I-Ching; Mai, Hsiu-Chin; Kuo, Po-Lin; Chang, Jer-Ming; Hwang, Shang-Jyh; Chen, Hung-Chun

    2016-01-01

    Background and Aim: The ankle-brachial index (ABI) is recognized to be a good marker for atherosclerosis, and is useful in the diagnosis of peripheral artery occlusive disease (PAOD) which is prevalent among patients on hemodialysis (HD). Methods: This randomized trial aimed to evaluate the effect of far-infrared radiation (FIR) therapy on ABI in HD patients with PAOD. PAOD was defined as patients with ABI < 0.95. One hundred and eight HD patients were enrolled, including 50 in the control group and 58 in the FIR group. A WS TY101 FIR emitter was applied for 40 minutes during each HD session, three times per week for six months. The ABI was measured before and after the FIR therapy. Results: Regardless of FIR therapy, the bilateral ABI decreased (in the FIR group, left: 0.88±0.22 to 0.85±0.24, p = 0.188; right: 0.92±0.20 to 0.90±0.23, p = 0.372; in control group, left: 0.91±0.23 to 0.88±0.21, p = 0144; right: 0.93±0.17 to 0.89±0.21, p = 0.082). Multivariate logistic analysis of the FIR group revealed that high uric acid (odds ratio [OR]: 2.335; 95% confidence interval [CI]: 1.117-4.882; p =0.024) and aspirin use (OR: 16.463; 95% CI: 1.787-151.638; p =0.013) were independently associated with increased bilateral ABI after FIR therapy. Conclusions: This study demonstrates that ABI is not increased after FIR therapy in HD patients with PAOD. However, in the FIR group, patients with higher uric acid level or those who used aspirin have increased bilateral ABI after FIR therapy.

  14. Maximizing the spectral and energy efficiency of ARQ with a fixed outage probability

    KAUST Repository

    Hadjtaieb, Amir; Chelli, Ali; Alouini, Mohamed-Slim

    2015-01-01

    This paper studies the spectral and energy efficiency of automatic repeat request (ARQ) in Nakagami-m block-fading channels. The source encodes each packet into L similar sequences and transmits them to the destination in the L subsequent time slots

  15. Planck intermediate results: XLIII. Spectral energy distribution of dust in clusters of galaxies

    DEFF Research Database (Denmark)

    Adam, R.; Ade, P. A R; Aghanim, N.

    2016-01-01

    Although infrared (IR) overall dust emission from clusters of galaxies has been statistically detected using data from the Infrared Astronomical Satellite (IRAS), it has not been possible to sample the spectral energy distribution (SED) of this emission over its peak, and thus to break the degene...

  16. Localness of energy cascade in hydrodynamic turbulence, II. Sharp spectral filter

    Energy Technology Data Exchange (ETDEWEB)

    Aluie, Hussein [Los Alamos National Laboratory; Eyink, Gregory L [JOHNS HOPKINS UNIV.

    2009-01-01

    We investigate the scale-locality of subgrid-scale (SGS) energy flux and interband energy transfers defined by the sharp spectral filter. We show by rigorous bounds, physical arguments, and numerical simulations that the spectral SGS flux is dominated by local triadic interactions in an extended turbulent inertial range. Interband energy transfers are also shown to be dominated by local triads if the spectral bands have constant width on a logarithmic scale. We disprove in particular an alternative picture of 'local transfer by nonlocal triads,' with the advecting wavenumber mode at the energy peak. Although such triads have the largest transfer rates of all individual wavenumber triads, we show rigorously that, due to their restricted number, they make an asymptotically negligible contribution to energy flux and log-banded energy transfers at high wavenumbers in the inertial range. We show that it is only the aggregate effect of a geometrically increasing number of local wavenumber triads which can sustain an energy cascade to small scales. Furthermore, nonlocal triads are argued to contribute even less to the space-average energy flux than is implied by our rigorous bounds, because of additional cancellations from scale-decorrelation effects. We can thus recover the -4/3 scaling of nonlocal contributions to spectral energy flux predicted by Kraichnan's abridged Lagrangian-history direct-interaction approximation and test-field model closures. We support our results with numerical data from a 512{sup 3} pseudospectral simulation of isotropic turbulence with phase-shift dealiasing. We also discuss a rigorous counterexample of Eyink [Physica D 78, 222 (1994)], which showed that nonlocal wavenumber triads may dominate in the sharp spectral flux (but not in the SGS energy flux for graded filters). We show that this mathematical counter example fails to satisfy reasonable physical requirements for a turbulent velocity field, which are employed in our

  17. Analysis of the Herschel/Hexos Spectral Survey Toward Orion South: A Massive Protostellar Envelope with Strong External Irradiation

    NARCIS (Netherlands)

    Tahani, K.; Plume, R.; Bergin, E. A.; Tolls, V.; Phillips, T. G.; Caux, E.; Cabrit, S.; Goicoechea, J. R.; Goldsmith, P. F.; Johnstone, D.; Lis, D. C.; Pagani, L.; Menten, K. M.; Müller, H. S. P.; Ossenkopf-Okada, V.; Pearson, J. C.; van der Tak, F. F. S.

    2016-01-01

    We present results from a comprehensive submillimeter spectral survey toward the source Orion South, based on data obtained with the Heterodyne Instrument for the Far-Infrared instrument on board the Herschel Space Observatory, covering the frequency range of 480 to 1900 GHz. We detect 685 spectral

  18. Investigation of JI and DI CMOS FXR response at different spectral energies

    International Nuclear Information System (INIS)

    Honnold, V.R.; Goldberg, M.; Schreiner, W.A.; Witteles, A.A.

    1975-01-01

    The transient response of both junction isolated (JI) and dielectrically isolated (DI) CMOS circuits has been investigated in three FXR environments of differing energy spectrums. The offset recovery times have been measured and analyzed for both structures. It is shown that while the DI circuit (HD4007) did not exhibit a four layer type latchup action, its transient response persisted for a time longer than is expected for this type of device. A possible mechanism for this observed response is developed and discussed. JI circuits (CD4007) exposed under the same conditions exhibited four layer device action and one sample at low spectral energies latched-up. The conditions for the latchup to occur including the four layer device paths are discussed. Finally, the dependence of the x-ray transient response on the spectral energy is considered. For the lower energy FXR source, latchup was observed in a CD4007 sample. This latchup was not observed at more than double the dose rate when a high energy FXR was used. This result is attributed to dose enhancement, and a device enhancement factor may also be involved. The dose enhancement factor is estimated from the work of Long, and points up the importance of accounting for the spectral energy content in simulating a given nuclear threat spectrum

  19. EMBEDDED PROTOSTARS IN THE DUST, ICE, AND GAS IN TIME (DIGIT) HERSCHEL KEY PROGRAM: CONTINUUM SEDs, AND AN INVENTORY OF CHARACTERISTIC FAR-INFRARED LINES FROM PACS SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Green, Joel D.; Evans, Neal J. II; Rascati, Michelle R. [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); Jorgensen, Jes K.; Dionatos, Odysseas; Lindberg, Johan E. [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Herczeg, Gregory J. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Kristensen, Lars E.; Yildiz, Umut A.; Van Kempen, Tim A. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands); Lee, Jeong-Eun [Department of Astronomy and Space Science, Kyung Hee University, Gyeonggi 446-701 (Korea, Republic of); Salyk, Colette [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Meeus, Gwendolyn [Dpt. Fisica Teorica, Universidad Autonoma de Madrid, Campus Cantoblanco, E-28049 Madrid (Spain); Bouwman, Jeroen [Max Planck Institute for Astronomy, D-69117 Heidelberg (Germany); Visser, Ruud; Bergin, Edwin A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); Van Dishoeck, Ewine F.; Karska, Agata; Fedele, Davide [Max-Planck Institute for Extraterrestrial Physics, Postfach 1312, D-85741 Garching (Germany); Dunham, Michael M., E-mail: joel@astro.as.utexas.edu [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Collaboration: DIGIT Team1

    2013-06-20

    We present 50-210 {mu}m spectral scans of 30 Class 0/I protostellar sources, obtained with Herschel-PACS, and 0.5-1000 {mu}m spectral energy distributions, as part of the Dust, Ice, and Gas in Time Key Program. Some sources exhibit up to 75 H{sub 2}O lines ranging in excitation energy from 100 to 2000 K, 12 transitions of OH, and CO rotational lines ranging from J = 14 {yields} 13 up to J = 40 {yields} 39. [O I] is detected in all but one source in the entire sample; among the sources with detectable [O I] are two very low luminosity objects. The mean 63/145 {mu}m [O I] flux ratio is 17.2 {+-} 9.2. The [O I] 63 {mu}m line correlates with L{sub bol}, but not with the time-averaged outflow rate derived from low-J CO maps. [C II] emission is in general not local to the source. The sample L{sub bol} increased by 1.25 (1.06) and T{sub bol} decreased to 0.96 (0.96) of mean (median) values with the inclusion of the Herschel data. Most CO rotational diagrams are characterized by two optically thin components ( = (0.70 {+-} 1.12) x 10{sup 49} total particles). N{sub CO} correlates strongly with L{sub bol}, but neither T{sub rot} nor N{sub CO}(warm)/N{sub CO}(hot) correlates with L{sub bol}, suggesting that the total excited gas is related to the current source luminosity, but that the excitation is primarily determined by the physics of the interaction (e.g., UV-heating/shocks). Rotational temperatures for H{sub 2}O ( = 194 +/- 85 K) and OH ( = 183 +/- 117 K) are generally lower than for CO, and much of the scatter in the observations about the best fit is attributed to differences in excitation conditions and optical depths among the detected lines.

  20. Quantitative analysis of the dual-energy CT virtual spectral curve for focal liver lesions characterization

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qi, E-mail: wq20@hotmail.com; Shi, Gaofeng, E-mail: gaofengs62@sina.com; Qi, Xiaohui, E-mail: qixiaohui1984@163.com; Fan, Xueli, E-mail: 407849960@qq.com; Wang, Lijia, E-mail: 893197597@qq.com

    2014-10-15

    Highlights: • We establish a feasible method using the virtual spectral curves (VSC) to differentiate focal liver lesions using DECT. • Our study shows the slope of the VSC can be used to differentiate between hemangioma, HCC, metastasis and cyst. • Importantly, the diagnostic specificities associated with using the slope to diagnose both hemangioma and cysts were 100%. - Abstract: Objective: To assess the usefulness of the spectral curve slope of dual-energy CT (DECT) for differentiating between hepatocellular carcinoma (HCC), hepatic metastasis, hemangioma (HH) and cysts. Methods: In total, 121 patients were imaged in the portal venous phase using dual-energy mode. Of these patients, 23 patients had HH, 28 patients had HCC, 40 patients had metastases and 30 patients had simple cysts. The spectral curves of the hepatic lesions were derived from the 40–190 keV levels of virtual monochromatic spectral imaging. The spectral curve slopes were calculated from 40 to 110 keV. The slopes were compared using the Kruskal–Wallis test. Receiver operating characteristic curves (ROC) were used to determine the optimal cut-off value of the slope of the spectral curve to differentiate between the lesions. Results: The spectral curves of the four lesion types had different baseline levels. The HH baseline level was the highest followed by HCC, metastases and cysts. The slopes of the spectral curves of HH, HCC, metastases and cysts were 3.81 ± 1.19, 1.49 ± 0.57, 1.06 ± 0.76 and 0.13 ± 0.17, respectively. These values were significantly different (P < 0.008). Based on ROC analysis, the respective diagnostic sensitivity and specificity were 87% and 100% for hemangioma (cut-off value ≥ 2.988), 82.1% and 65.9% for HCC (cut-off value 1.167–2.998), 65.9% and 59% for metastasis (cut-off value 0.133–1.167) and 44.4% and 100% for cysts (cut-off value ≤ 0.133). Conclusion: Quantitative analysis of the DECT spectral curve in the portal venous phase can be used to

  1. The Small Magellanic Cloud in the far infrared. I. ISO's 170 mu m map and revisit of the IRAS 12-100 mu m data

    Science.gov (United States)

    Wilke, K.; Stickel, M.; Haas, M.; Herbstmeier, U.; Klaas, U.; Lemke, D.

    2003-04-01

    The ISOPHOT experiment onboard the ISO satellite generated a complete view of the Small Magellanic Cloud (SMC) at 170 mu m with 1.5 arcmin resolution. The map is analysed using an automated photometry program enabling accurate photometric characterization of the far infrared (FIR) emitting regions. An integrated FIR luminosity of 8.5x 107 Lsun is obtained, leading to a star formation rate of SFRFIR=0.015 Msun/yr. With an average dust temperature of TD, 170/100}=20.5 K>, the total dust mass follows to MD=3.7x105 Msun. In this paper, the sources detected at 170 mu m are compared with those obtainable from the IRAS satellite data. For this purpose, the 12 mu m, 25 mu m, 60 mu m, and 100 mu m IRAS high resolution (HiRes) maps of the SMC are re-examined using the same method. In contrast to former studies, this provides an all-band ISO/IRAS source catalog which is no longer based on eyeball classification, but relies on an algorithm which is capable of automated, repeatable photometry, even for irregular sources. In the mid infrared IRAS bands numerous bright FIR emitting regions in the SMC are detected and classified: 73 sources are found at 12 mu m, 135 at 25 mu m (most of them with Fnu =2.0 Jy. Comparable numbers are found for the two FIR IRAS maps at 60 mu m (384) and 100 mu m (338) with fluxes up to 450 Jy. 70 of the 243 170 mu m sources are assigned a general SED type (``cold'', ``warm'', i.e., 30 K) for the first time. A comparison with earlier IRAS results suggests that many source flux densities in those studies have been under- or overestimated because of non-standardized fitting methods. Many sources with flux densities up to 40 Jy listed in former catalogs cannot be identified in our data. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, The Netherlands and the UK) and with the participation of ISAS and NASA. The tables in Appendices A to E are only available in

  2. MEASURING STAR FORMATION RATES AND FAR-INFRARED COLORS OF HIGH-REDSHIFT GALAXIES USING THE CO(7–6) AND [N II] 205 μm LINES

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Nanyao; Zhao, Yinghe; Xu, C. Kevin; Howell, Justin; Mazzarella, Joseph M.; Schulz, Bernhard [Infrared Processing and Analysis Center, California Institute of Technology, MS 100-22, Pasadena, CA 91125 (United States); Gao, Yu; Liu, Lijie [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Díaz-Santos, Tanio; Armus, Lee [Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States); Charmandaris, Vassilis [Department of Physics, University of Crete, GR-71003 Heraklion (Greece); Inami, Hanae [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Privon, George C. [Departamento de Astronomía, Universidad de Concepción, Casilla 160 C, Concepción (Chile); Lord, Steven D. [The SETI Institute, 189 Bernardo Avenue Suite 100, Mountain View, CA 94043 (United States); Sanders, David B. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Van der Werf, Paul P., E-mail: lu@ipac.caltech.edu [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)

    2015-03-20

    To better characterize the global star formation activity in a galaxy, one needs to know not only the star formation rate (SFR) but also the rest-frame, far-infrared color (e.g., the 60–100 μm color, C(60/100)) of the dust emission. The latter probes the average intensity of the dust heating radiation field and scales statistically with the effective SFR surface density in star-forming galaxies including (ultra-)luminous infrared galaxies ((U)LIRGs). To this end, here we exploit a new spectroscopic approach involving only two emission lines: CO(7–6) at 372 μm and [N ii] at 205 μm([N ii]{sub 205μm}). For local (U)LIRGs, the ratios of the CO(7–6) luminosity (L{sub CO(7–6)}) to the total infrared luminosity (L{sub IR}; 8–1000 μm) are fairly tightly distributed (to within ∼0.12 dex) and show little dependence on C(60/100). This makes L{sub CO(7–6)} a good SFR tracer, which is less contaminated by active galactic nuclei than L{sub IR} and may also be much less sensitive to metallicity than L{sub CO(1–0)}. Furthermore, the logarithmic [N ii]{sub 205μm}/CO(7–6) luminosity ratio depends fairly strongly (at a slope of ∼ −1.4) on C(60/100), with a modest scatter (∼0.23 dex). This makes it a useful estimator on C(60/100) with an implied uncertainty of ∼0.15 (or ≲4 K in the dust temperature (T{sub dust}) in the case of a graybody emission with T{sub dust} ≳ 30 K and a dust emissivity index β ≥ 1). Our locally calibrated SFR and C(60/100) estimators are shown to be consistent with the published data of (U)LIRGs of z up to ∼6.5.

  3. Coherent Structures and Spectral Energy Transfer in Turbulent Plasma: A Space-Filter Approach

    Science.gov (United States)

    Camporeale, E.; Sorriso-Valvo, L.; Califano, F.; Retinò, A.

    2018-03-01

    Plasma turbulence at scales of the order of the ion inertial length is mediated by several mechanisms, including linear wave damping, magnetic reconnection, the formation and dissipation of thin current sheets, and stochastic heating. It is now understood that the presence of localized coherent structures enhances the dissipation channels and the kinetic features of the plasma. However, no formal way of quantifying the relationship between scale-to-scale energy transfer and the presence of spatial structures has been presented so far. In the Letter we quantify such a relationship analyzing the results of a two-dimensional high-resolution Hall magnetohydrodynamic simulation. In particular, we employ the technique of space filtering to derive a spectral energy flux term which defines, in any point of the computational domain, the signed flux of spectral energy across a given wave number. The characterization of coherent structures is performed by means of a traditional two-dimensional wavelet transformation. By studying the correlation between the spectral energy flux and the wavelet amplitude, we demonstrate the strong relationship between scale-to-scale transfer and coherent structures. Furthermore, by conditioning one quantity with respect to the other, we are able for the first time to quantify the inhomogeneity of the turbulence cascade induced by topological structures in the magnetic field. Taking into account the low space-filling factor of coherent structures (i.e., they cover a small portion of space), it emerges that 80% of the spectral energy transfer (both in the direct and inverse cascade directions) is localized in about 50% of space, and 50% of the energy transfer is localized in only 25% of space.

  4. Critically Evaluated Energy Levels, Spectral Lines, Transition Probabilities, and Intensities of Neutral Vanadium (V i)

    Energy Technology Data Exchange (ETDEWEB)

    Saloman, Edward B. [Dakota Consulting, Inc., 1110 Bonifant Street, Suite 310, Silver Spring, MD 20910 (United States); Kramida, Alexander [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)

    2017-08-01

    The energy levels, observed spectral lines, and transition probabilities of the neutral vanadium atom, V i, have been compiled. Also included are values for some forbidden lines that may be of interest to the astrophysical community. Experimental Landé g -factors and leading percentage compositions for the levels are included where available, as well as wavelengths calculated from the energy levels (Ritz wavelengths). Wavelengths are reported for 3985 transitions, and 549 energy levels are determined. The observed relative intensities normalized to a common scale are provided.

  5. Energy Calibration of the Pixels of Spectral X-ray Detectors

    CERN Document Server

    Panta, Raj Kumar; Bell, Stephen T; Anderson, Nigel G; Butler, Anthony P; Butler, Philip H

    2015-01-01

    The energy information acquired using spectral X-ray detectors allows noninvasive identification and characterization of chemical components of a material. To achieve this, it is important that the energy response of the detector is calibrated. The established techniques for energy calibration are not practical for routine use in pre-clinical or clinical research environment. This is due to the requirements of using monochromatic radiation sources such as synchrotron, radio-isotopes, and prohibitively long time needed to set up the equipment and make measurements. To address these limitations, we have developed an automated technique for calibrating the energy response of the pixels in a spectral X-ray detector that runs with minimal user intervention. This technique uses the X-ray tube voltage (kVp) as a reference energy, which is stepped through an energy range of interest. This technique locates the energy threshold where a pixel transitions from not-counting (off) to counting (on). Similarly, we have deve...

  6. Quantitative material decomposition using spectral computed tomography with an energy-resolved photon-counting detector

    International Nuclear Information System (INIS)

    Lee, Seungwan; Choi, Yu-Na; Kim, Hee-Joung

    2014-01-01

    Dual-energy computed tomography (CT) techniques have been used to decompose materials and characterize tissues according to their physical and chemical compositions. However, these techniques are hampered by the limitations of conventional x-ray detectors operated in charge integrating mode. Energy-resolved photon-counting detectors provide spectral information from polychromatic x-rays using multiple energy thresholds. These detectors allow simultaneous acquisition of data in different energy ranges without spectral overlap, resulting in more efficient material decomposition and quantification for dual-energy CT. In this study, a pre-reconstruction dual-energy CT technique based on volume conservation was proposed for three-material decomposition. The technique was combined with iterative reconstruction algorithms by using a ray-driven projector in order to improve the quality of decomposition images and reduce radiation dose. A spectral CT system equipped with a CZT-based photon-counting detector was used to implement the proposed dual-energy CT technique. We obtained dual-energy images of calibration and three-material phantoms consisting of low atomic number materials from the optimal energy bins determined by Monte Carlo simulations. The material decomposition process was accomplished by both the proposed and post-reconstruction dual-energy CT techniques. Linear regression and normalized root-mean-square error (NRMSE) analyses were performed to evaluate the quantitative accuracy of decomposition images. The calibration accuracy of the proposed dual-energy CT technique was higher than that of the post-reconstruction dual-energy CT technique, with fitted slopes of 0.97–1.01 and NRMSEs of 0.20–4.50% for all basis materials. In the three-material phantom study, the proposed dual-energy CT technique decreased the NRMSEs of measured volume fractions by factors of 0.17–0.28 compared to the post-reconstruction dual-energy CT technique. It was concluded that the

  7. Maximizing the spectral and energy efficiency of ARQ with a fixed outage probability

    KAUST Repository

    Hadjtaieb, Amir

    2015-10-05

    This paper studies the spectral and energy efficiency of automatic repeat request (ARQ) in Nakagami-m block-fading channels. The source encodes each packet into L similar sequences and transmits them to the destination in the L subsequent time slots. The destination combines the L sequences using maximal ratio combining and tries to decode the information. In case of decoding failure, the destination feeds back a negative acknowledgment and then the source sends the same L sequences to the destination. This process continues until successful decoding occurs at the destination with no limit on the number of retransmissions. We consider two optimization problems. In the first problem, we maximize the spectral efficiency of the system with respect to the rate for a fixed power. In the second problem, we maximize the energy efficiency with respect to the transmitted power for a fixed rate. © 2015 IEEE.

  8. A rediscussion of the atmospheric extinction and the absolute spectral-energy distribution of Vega

    International Nuclear Information System (INIS)

    Hayes, D.S.; Latham, D.W.

    1975-01-01

    For both the Lick and the Palomar calibrations of the spectral-energy distribution of Vega, the atmospheric extinction was treated incorrectly. We present a model for extinction in the Earth's atmosphere and use this model to calculate corrections to the Lick and Palomar calibrations. We also describe a method that can be used to fabricate mean extinction coefficients for any mountain observatory. We combine selected portions of the corrected Lick and corrected Palomar calibrations with the new Mount Hopkins calibration to generate an absolute spectral-energy distibution of Vega over the wavelength range 3300--10,800 A. Until better measurements become available, we recommend the use of this calibration for all practical applications

  9. HERSCHEL/PACS SURVEY OF PROTOPLANETARY DISKS IN TAURUS/AURIGA—OBSERVATIONS OF [O I] AND [C II], AND FAR-INFRARED CONTINUUM

    International Nuclear Information System (INIS)

    Howard, Christian D.; Sandell, Göran; Vacca, William D.; Duchêne, Gaspard; Mathews, Geoffrey; Augereau, Jean-Charles; Ménard, Francois; Pinte, Christophe; Podio, Linda; Thi, Wing-Fai; Barrado, David; Riviere-Marichalar, Pablo; Dent, William R. F.; Eiroa, Carlos; Meeus, Gwendolyn; Grady, Carol; Roberge, Aki; Kamp, Inga; Vicente, Silvia; Williams, Jonathan P.

    2013-01-01

    The Herschel Space Observatory was used to observe ∼120 pre-main-sequence stars in Taurus as part of the GASPS Open Time Key project. Photodetector Array Camera and Spectrometer was used to measure the continuum as well as several gas tracers such as [O I] 63 μm, [O I] 145 μm, [C II] 158 μm, OH, H 2 O, and CO. The strongest line seen is [O I] at 63 μm. We find a clear correlation between the strength of the [O I] 63 μm line and the 63 μm continuum for disk sources. In outflow sources, the line emission can be up to 20 times stronger than in disk sources, suggesting that the line emission is dominated by the outflow. The tight correlation seen for disk sources suggests that the emission arises from the inner disk (<50 AU) and lower surface layers of the disk where the gas and dust are coupled. The [O I] 63 μm is fainter in transitional stars than in normal Class II disks. Simple spectral energy distribution models indicate that the dust responsible for the continuum emission is colder in these disks, leading to weaker line emission. [C II] 158 μm emission is only detected in strong outflow sources. The observed line ratios of [O I] 63 μm to [O I] 145 μm are in the regime where we are insensitive to the gas-to-dust ratio, neither can we discriminate between shock or photodissociation region emission. We detect no Class III object in [O I] 63 μm and only three in continuum, at least one of which is a candidate debris disk

  10. Algorithms for spectral calibration of energy-resolving small-pixel detectors

    International Nuclear Information System (INIS)

    Scuffham, J; Veale, M C; Wilson, M D; Seller, P

    2013-01-01

    Small pixel Cd(Zn)Te detectors often suffer from inter-pixel variations in gain, resulting in shifts in the individual energy spectra. These gain variations are mainly caused by inclusions and defects within the crystal structure, which affect the charge transport within the material causing a decrease in the signal pulse height. In imaging applications, spectra are commonly integrated over a particular peak of interest. This means that the individual pixels must be accurately calibrated to ensure that the same portion of the spectrum is integrated in every pixel. The development of large-area detectors with fine pixel pitch necessitates automated algorithms for this spectral calibration, due to the very large number of pixels. Algorithms for automatic spectral calibration require accurate determination of characteristic x-ray or photopeak positions on a pixelwise basis. In this study, we compare two peak searching spectral calibration algorithms for a small-pixel CdTe detector in gamma spectroscopic imaging. The first algorithm uses rigid search ranges to identify peaks in each pixel spectrum, based on the average peak positions across all pixels. The second algorithm scales the search ranges on the basis of the position of the highest-energy peak relative to the average across all pixels. In test spectra acquired with Tc-99m, we found that the rigid search algorithm failed to correctly identify the target calibraton peaks in up to 4% of pixels. In contrast, the scaled search algorithm failed in only 0.16% of pixels. Failures in the scaled search algorithm were attributed to the presence of noise events above the main photopeak, and possible non-linearities in the spectral response in a small number of pixels. We conclude that a peak searching algorithm based on scaling known peak spacings is simple to implement and performs well for the spectral calibration of pixellated radiation detectors

  11. Optimal Monochromatic Energy Levels in Spectral CT Pulmonary Angiography for the Evaluation of Pulmonary Embolism

    Science.gov (United States)

    Wu, Huawei; Zhang, Qing; Hua, Jia; Hua, Xiaolan; Xu, Jianrong

    2013-01-01

    Background The aim of this study was to determine the optimal monochromatic spectral CT pulmonary angiography (sCTPA) levels to obtain the highest image quality and diagnostic confidence for pulmonary embolism detection. Methods The Institutional Review Board of the Shanghai Jiao Tong University School of Medicine approved this study, and written informed consent was obtained from all participating patients. Seventy-two patients with pulmonary embolism were scanned with spectral CT mode in the arterial phase. One hundred and one sets of virtual monochromatic spectral (VMS) images were generated ranging from 40 keV to 140 keV. Image noise, clot diameter and clot to artery contrast-to-noise ratio (CNR) from seven sets of VMS images at selected monochromatic levels in sCTPA were measured and compared. Subjective image quality and diagnostic confidence for these images were also assessed and compared. Data were analyzed by paired t test and Wilcoxon rank sum test. Results The lowest noise and the highest image quality score for the VMS images were obtained at 65 keV. The VMS images at 65 keV also had the second highest CNR value behind that of 50 keV VMS images. There was no difference in the mean noise and CNR between the 65 keV and 70 keV VMS images. The apparent clot diameter correlated with the keV levels. Conclusions The optimal energy level for detecting pulmonary embolism using dual-energy spectral CT pulmonary angiography was 65–70 keV. Virtual monochromatic spectral images at approximately 65–70 keV yielded the lowest image noise, high CNR and highest diagnostic confidence for the detection of pulmonary embolism. PMID:23667583

  12. Deuterium depleted water effect on seawater spectral energy and marine phytoplankton

    International Nuclear Information System (INIS)

    Mirza, Maria; Zaharia, Mihaela; Cristescu, T.M.; Titescu, Gh.

    2002-01-01

    Solar radiation is the primary source of new energy in most aquatic ecosystems and it is the sun variability in amount and spectral distribution that drives many of the changes in material flux on different time and space scales. The dependency of ecosystem dynamics on sunlight is largely attributable to the simple fact that plants require solar radiation to carry out photosynthesis. The resulting primary production (the rate of the plant growth and reproduction) is an index of aquatic processes, including food web dynamics and biogeochemical cycling of compounds that affect everything from aquatic chemistry to regional and global weather patterns. Light dependent processes in plants (photo-synthesis, photoinhibition, phototaxis and photoprotection) and in aquatic environment, animal vision and microbial mediation of the photo-dissociation of chemical have evolved over millennia and most of them are regulated or at least influenced by the spectral composition of the light field The paper deals with the investigation of relations between water spectral energy modified by deuterium depleted water (DDW) and the microphyte alga Tetraselmis suecica or the total marine micro-phytoplankton growth. (authors)

  13. Modelling the carbon AGB star R Sculptoris. Constraining the dust properties in the detached shell based on far-infrared and sub-millimeter observations

    Science.gov (United States)

    Brunner, M.; Maercker, M.; Mecina, M.; Khouri, T.; Kerschbaum, F.

    2018-06-01

    Context. On the asymptotic giant branch (AGB), Sun-like stars lose a large portion of their mass in an intensive wind and enrich the surrounding interstellar medium with nuclear processed stellar material in the form of molecular gas and dust. For a number of carbon-rich AGB stars, thin detached shells of gas and dust have been observed. These shells are formed during brief periods of increased mass loss and expansion velocity during a thermal pulse, and open up the possibility to study the mass-loss history of thermally pulsing AGB stars. Aims: We study the properties of dust grains in the detached shell around the carbon AGB star R Scl and aim to quantify the influence of the dust grain properties on the shape of the spectral energy distribution (SED) and the derived dust shell mass. Methods: We modelled the SED of the circumstellar dust emission and compared the models to observations, including new observations of Herschel/PACS and SPIRE (infrared) and APEX/LABOCA (sub-millimeter). We derived present-day mass-loss rates and detached shell masses for a variation of dust grain properties (opacities, chemical composition, grain size, and grain geometry) to quantify the influence of changing dust properties to the derived shell mass. Results: The best-fitting mass-loss parameters are a present-day dust mass-loss rate of 2 × 10-10 M⊙ yr-1 and a detached shell dust mass of (2.9 ± 0.3) × 10-5 M⊙. Compared to similar studies, the uncertainty on the dust mass is reduced by a factor of 4. We find that the size of the grains dominates the shape of the SED, while the estimated dust shell mass is most strongly affected by the geometry of the dust grains. Additionally, we find a significant sub-millimeter excess that cannot be reproduced by any of the models, but is most likely not of thermal origin. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  14. Dual energy spectral CT imaging for the evaluation of small hepatocellular carcinoma microvascular invasion.

    Science.gov (United States)

    Yang, Chuang-Bo; Zhang, Shuang; Jia, Yong-Jun; Yu, Yong; Duan, Hai-Feng; Zhang, Xi-Rong; Ma, Guang-Ming; Ren, Chenglong; Yu, Nan

    2017-10-01

    To study the clinical value of dual-energy spectral CT in the quantitative assessment of microvascular invasion of small hepatocellular carcinoma. This study was approved by our ethics committee. 50 patients with small hepatocellular carcinoma who underwent contrast enhanced spectral CT in arterial phase (AP) and portal venous phase (VP) were enrolled. Tumour CT value and iodine concentration (IC) were measured from spectral CT images. The slope of spectral curve, normalized iodine concentration (NIC, to abdominal aorta) and ratio of IC difference between AP and VP (RIC AP-VP : [RIC AP-VP =(IC AP -IC VP )/IC AP ]) were calculated. Tumours were identified as either with or without microvascular invasion based on pathological results. Measurements were statistically compared using independent samples t test. The receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic performance of tumours microvascular invasion assessment. The 70keV images were used to simulate the results of conventional CT scans for comparison. 56 small hepatocellular carcinomas were detected with 37 lesions (Group A) with microvascular invasion and 19 (Group B) without. There were significant differences in IC, NIC and slope in AP and RIC AP-VP between Group A (2.48±0.70mg/ml, 0.23±0.05, 3.39±1.01 and 0.28±0.16) and Group B (1.65±0.47mg/ml, 0.15±0.05, 2.22±0.64 and 0.03±0.24) (all phepatocellular carcinoma with and without microvascular invasion. Quantitative iodine concentration measurement in spectral CT may be used to provide a new method to improve the evaluation for small hepatocellular carcinoma microvascular invasion. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Toward Improved Modeling of Spectral Solar Irradiance for Solar Energy Applications: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yu [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sengupta, Manajit [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-10-19

    This study introduces the National Renewable Energy Laboratory's (NREL's) recent efforts to extend the capability of the Fast All-sky Radiation Model for Solar applications (FARMS) by computing spectral solar irradiances over both horizontal and inclined surfaces. A new model is developed by computing the optical thickness of the atmosphere using a spectral irradiance model for clear-sky conditions, SMARTS2. A comprehensive lookup table (LUT) of cloud bidirectional transmittance distribution functions (BTDFs) is precomputed for 2002 wavelength bands using an atmospheric radiative transfer model, libRadtran. The solar radiation transmitted through the atmosphere is given by considering all possible paths of photon transmission and the relevent scattering and absorption attenuation. Our results indicate that this new model has an accuracy that is similar to that of state-of-the-art radiative transfer models, but it is significantly more efficient.

  16. Planck early results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

    DEFF Research Database (Denmark)

    Aatrokoski, J.; Lähteenmäki, A.; Lavonen, N.

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz......, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase...... of development, shape the radio spectra as they move in the relativistic jet. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data...

  17. Recent Advances in Cardiac Computed Tomography: Dual Energy, Spectral and Molecular CT Imaging

    Science.gov (United States)

    Danad, Ibrahim; Fayad, Zahi A.; Willemink, Martin J.; Min, James K.

    2015-01-01

    Computed tomography (CT) evolved into a powerful diagnostic tool and it is impossible to imagine current clinical practice without CT imaging. Due to its widespread availability, ease of clinical application, superb sensitivity for detection of CAD, and non-invasive nature, CT has become a valuable tool within the armamentarium of the cardiologist. In the last few years, numerous technological advances in CT have occurred—including dual energy CT (DECT), spectral CT and CT-based molecular imaging. By harnessing the advances in technology, cardiac CT has advanced beyond the mere evaluation of coronary stenosis to an imaging modality tool that permits accurate plaque characterization, assessment of myocardial perfusion and even probing of molecular processes that are involved in coronary atherosclerosis. Novel innovations in CT contrast agents and pre-clinical spectral CT devices have paved the way for CT-based molecular imaging. PMID:26068288

  18. Study of the spectral and energy characteristics of lasing in the green spectral region by lithium fluoride with radiation color centers

    Energy Technology Data Exchange (ETDEWEB)

    Voitovich, A.P.; Kalinov, V.S.; Mikhnov, S.A.; Ovseichuk, S.I.

    1987-06-01

    The spectral and energy characteristics of lasers utilizing lithium fluoride with F2 and F3(+) color centers in transverse and longitudinal pumping schemes are studied. The feasibility of obtaining stable narrow-band radiation in the 510-570 nm range using a selective resonator is demonstrated. Consideration is given to the effect of lithium-fluoride crystal processing by excimer laser radiation at a wavelength of 308 nm on the spectroscopic and lasing characteristics of the F3(+) color center. After this processing, the laser efficiency in the green spectral region increases by more than a factor of two (reaching an efficiency of 14 percent). 7 references.

  19. ENERGY-DEPENDENT POWER SPECTRAL STATES AND ORIGIN OF APERIODIC VARIABILITY IN BLACK HOLE BINARIES

    International Nuclear Information System (INIS)

    Yu Wenfei; Zhang Wenda

    2013-01-01

    We found that the black hole candidate MAXI J1659–152 showed distinct power spectra, i.e., power-law noise (PLN) versus band-limited noise (BLN) plus quasi-periodic oscillations (QPOs) below and above about 2 keV, respectively, in observations with Swift and the Rossi X-ray Timing Explorer during the 2010 outburst, indicating a high energy cutoff of the PLN and a low energy cutoff of the BLN and QPOs around 2 keV. The emergence of the PLN and the fading of the BLN and QPOs initially took place below 2 keV when the source entered the hard intermediate state and settled in the soft state three weeks later. The evolution was accompanied by the emergence of the disk spectral component and decreases in the amplitudes of variability in the soft and hard X-ray bands. Our results indicate that the PLN is associated with an optically thick disk in both hard and intermediate states, and the power spectral state is independent of the X-ray energy spectral state in a broadband view. We suggest that in the hard or intermediate state, the BLN and QPOs emerge from the innermost hot flow subjected to Comptonization, while the PLN originates from the optically thick disk farther out. The energy cutoffs of the PLN and the BLN or QPOs then follow the temperature of the seed photons from the inner edge of the optically thick disk, while the high frequency cutoff of the PLN follows the orbital frequency of the inner edge of the optically thick disk as well.

  20. The importance of spectral separation: an assessment of dual-energy spectral separation for quantitative ability and dose efficiency.

    Science.gov (United States)

    Krauss, Bernhard; Grant, Katharine L; Schmidt, Bernhard T; Flohr, Thomas G

    2015-02-01

    One method to acquire dual-energy (DE) computed tomography (CT) data is to perform CT scans at 2 different x-ray tube voltages, typically 80 and 140 kV, either as 2 separate scans, by means of rapid kV switching, or with the use of 2 x-ray sources as in dual-source CT (DSCT) systems. In DSCT, it is possible to improve spectral separation with tin prefiltration (Sn) of the high-kV beam. Recently, x-ray tube voltages beyond the established range of 80 to 140 kV were commercially introduced, which enable additional voltage combinations for DE acquisitions, such as 80/150 Sn or 90/150 Sn kV. Here, we investigate the DE performance of several x-ray tube voltages and prefilter combinations on 2 DSCT scanners and the impact of the spectra on quantitative analysis and dose efficiency. Circular phantoms of different sizes (10-40 cm in diameter) equipped with cylindrical inserts containing water and diluted iodine contrast agent (14.5 mg/cm) were scanned using 2 different DSCT systems (SOMATOM Definition Flash and SOMATOM Force; Siemens AG, Forchheim, Germany). Five x-ray tube voltage combinations (80/140 Sn, 100/140 Sn, 80/150 Sn, 90/150 Sn, and 100/150 Sn kV) were investigated, and the results were compared with the previous standard acquisition technique (80/140 kV). As an example, 80/140 Sn kV means that 1 x-ray tube of the DSCT system was operated at 80 kV, whereas the other was operated at 140 kV with additional tin prefiltration (Sn). Dose values in terms of computed tomography dose index (CTDIvol) were kept constant between the different voltage combinations but adjusted with regard to object size according to automatic exposure control recommendations. Reconstructed images were processed using linear blending of the low- and high-kV CT images to combined images, as well as 3-material decomposition techniques to generate virtual noncontrast (VNC) images and iodine images. Contrast and pixel noise were evaluated, as well as DE ratios, which are defined as the CT value

  1. Structural and vibrational spectral investigations of melaminium maleate monohydrate by FTIR, FT-Raman and quantum chemical calculations

    Science.gov (United States)

    Arjunan, V.; Kalaivani, M.; Marchewka, M. K.; Mohan, S.

    2013-04-01

    The structural investigations of the molecular complex of melamine with maleic acid, namely melaminium maleate monohydrate have been carried out by quantum chemical methods in addition to FTIR, FT-Raman and far-infrared spectral studies. The quantum chemical studies were performed with DFT (B3LYP) method using 6-31G**, cc-pVDZ and 6-311++G** basis sets to determine the energy, structural and thermodynamic parameters of melaminium maleate monohydrate. The hydrogen atom from maleic acid was transferred to the melamine molecule giving the singly protonated melaminium cation. The ability of ions to form spontaneous three-dimensional structure through weak Osbnd H⋯O and Nsbnd H⋯O hydrogen bonds shows notable vibrational effects.

  2. Structural and vibrational spectral investigations of melaminium maleate monohydrate by FTIR, FT-Raman and quantum chemical calculations.

    Science.gov (United States)

    Arjunan, V; Kalaivani, M; Marchewka, M K; Mohan, S

    2013-04-15

    The structural investigations of the molecular complex of melamine with maleic acid, namely melaminium maleate monohydrate have been carried out by quantum chemical methods in addition to FTIR, FT-Raman and far-infrared spectral studies. The quantum chemical studies were performed with DFT (B3LYP) method using 6-31G(**), cc-pVDZ and 6-311++G(**) basis sets to determine the energy, structural and thermodynamic parameters of melaminium maleate monohydrate. The hydrogen atom from maleic acid was transferred to the melamine molecule giving the singly protonated melaminium cation. The ability of ions to form spontaneous three-dimensional structure through weak OH···O and NH···O hydrogen bonds shows notable vibrational effects. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. SPECTRAL ENERGY DISTRIBUTION OF MARKARIAN 501: QUIESCENT STATE VERSUS EXTREME OUTBURST

    International Nuclear Information System (INIS)

    Acciari, V. A.; Benbow, W.; Arlen, T.; Aune, T.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R.; Boettcher, M.; Boltuch, D.; Bradbury, S. M.; Cannon, A.; Cesarini, A.; Ciupik, L.; Cui, W.; Finley, J. P.; Duke, C.; Errando, M.; Falcone, A.; Finnegan, G.

    2011-01-01

    The very high energy (VHE; E > 100 GeV) blazar Markarian 501 (Mrk 501) has a well-studied history of extreme spectral variability and is an excellent laboratory for studying the physical processes within the jets of active galactic nuclei. However, there are few detailed multiwavelength studies of Mrk 501 during its quiescent state, due to its low luminosity. A short-term multiwavelength study of Mrk 501 was coordinated in 2009 March, focusing around a multi-day observation with the Suzaku X-ray satellite and including γ-ray data from VERITAS, MAGIC, and the Fermi Gamma-ray Space Telescope with the goal of providing a well-sampled multiwavelength baseline measurement of Mrk 501 in the quiescent state. The results of these quiescent-state observations are compared to the historically extreme outburst of 1997 April 16, with the goal of examining variability of the spectral energy distribution (SED) between the two states. The derived broadband SED shows the characteristic double-peaked profile. We find that the X-ray peak shifts by over two orders of magnitude in photon energy between the two flux states while the VHE peak varies little. The limited shift in the VHE peak can be explained by the transition to the Klein-Nishina (KN) regime. Synchrotron self-Compton models are matched to the data and the implied KN effects are explored.

  4. Spectral Energy Distribution of Markarian 501: Quiescent State Versus Extreme Outburst

    Science.gov (United States)

    Acciari, V. A.; Arlen, T.; Aune, T.; Beilicke, M.; Benbow, W.; Böttcher, M.; Boltuch, D.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.; Cannon, A.; Cesarini, A.; Ciupik, L.; Cui, W.; Dickherber, R.; Duke, C.; Errando, M.; Falcone, A.; Finley, J. P.; Finnegan, G.; Fortson, L.; Furniss, A.; Galante, N.; Gall, D.; Godambe, S.; Grube, J.; Guenette, R.; Gyuk, G.; Hanna, D.; Holder, J.; Huang, D.; Hui, C. M.; Humensky, T. B.; Imran, A.; Kaaret, P.; Karlsson, N.; Kertzman, M.; Kieda, D.; Konopelko, A.; Krawczynski, H.; Krennrich, F.; Madhavan, A. S.; Maier, G.; McArthur, S.; McCann, A.; Moriarty, P.; Ong, R. A.; Otte, A. N.; Pandel, D.; Perkins, J. S.; Pichel, A.; Pohl, M.; Quinn, J.; Ragan, K.; Reyes, L. C.; Reynolds, P. T.; Roache, E.; Rose, H. J.; Schroedter, M.; Sembroski, G. H.; Steele, D.; Swordy, S. P.; Theiling, M.; Thibadeau, S.; Varlotta, A.; Vassiliev, V. V.; Vincent, S.; Wakely, S. P.; Ward, J. E.; Weekes, T. C.; Weinstein, A.; Weisgarber, T.; Williams, D. A.; Wood, M.; Zitzer, B.; VERITAS Collaboration; Aleksić, J.; Antonelli, L. A.; Antoranz, P.; Backes, M.; Barrio, J. A.; Bastieri, D.; Becerra González, J.; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Bordas, P.; Borla Tridon, D.; Bosch-Ramon, V.; Bose, D.; Braun, I.; Bretz, T.; Camara, M.; Carmona, E.; Carosi, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Dazzi, F.; De Angelis, A.; De Cea del Pozo, E.; De Lotto, B.; De Maria, M.; De Sabata, F.; Delgado Mendez, C.; Diago Ortega, A.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Elsaesser, D.; Errando, M.; Ferenc, D.; Fonseca, M. V.; Font, L.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Giavitto, G.; Godinović, N.; Hadasch, D.; Herrero, A.; Hildebrand, D.; Höhne-Mönch, D.; Hose, J.; Hrupec, D.; Jogler, T.; Klepser, S.; Krähenbühl, T.; Kranich, D.; Krause, J.; La Barbera, A.; Leonardo, E.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Lorenz, E.; Majumdar, P.; Makariev, M.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Miyamoto, H.; Moldón, J.; Moralejo, A.; Nieto, D.; Nilsson, K.; Orito, R.; Oya, I.; Paoletti, R.; Paredes, J. M.; Partini, S.; Pasanen, M.; Pauss, F.; Pegna, R. G.; Perez-Torres, M. A.; Persic, M.; Peruzzo, L.; Pochon, J.; Prada, F.; Prada Moroni, P. G.; Prandini, E.; Puchades, N.; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rissi, M.; Rügamer, S.; Saggion, A.; Saito, K.; Saito, T. Y.; Salvati, M.; Sánchez-Conde, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shayduk, M.; Shore, S. N.; Sierpowska-Bartosik, A.; Sillanpää, A.; Sitarek, J.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamerra, A.; Steinke, B.; Storz, J.; Strah, N.; Struebig, J. C.; Suric, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres, D. F.; Vankov, H.; Wagner, R. M.; Weitzel, Q.; Zabalza, V.; Zandanel, F.; Zanin, R.; MAGIC Collaboration; Paneque, D.; Hayashida, M.

    2011-03-01

    The very high energy (VHE; E > 100 GeV) blazar Markarian 501 (Mrk 501) has a well-studied history of extreme spectral variability and is an excellent laboratory for studying the physical processes within the jets of active galactic nuclei. However, there are few detailed multiwavelength studies of Mrk 501 during its quiescent state, due to its low luminosity. A short-term multiwavelength study of Mrk 501 was coordinated in 2009 March, focusing around a multi-day observation with the Suzaku X-ray satellite and including γ-ray data from VERITAS, MAGIC, and the Fermi Gamma-ray Space Telescope with the goal of providing a well-sampled multiwavelength baseline measurement of Mrk 501 in the quiescent state. The results of these quiescent-state observations are compared to the historically extreme outburst of 1997 April 16, with the goal of examining variability of the spectral energy distribution (SED) between the two states. The derived broadband SED shows the characteristic double-peaked profile. We find that the X-ray peak shifts by over two orders of magnitude in photon energy between the two flux states while the VHE peak varies little. The limited shift in the VHE peak can be explained by the transition to the Klein-Nishina (KN) regime. Synchrotron self-Compton models are matched to the data and the implied KN effects are explored.

  5. Integrated Spectral Energy Distributions and Absorption Feature Indices of Single Stellar Populations

    OpenAIRE

    Zhang, Fenghui; Han, Zhanwen; Li, Lifang; Hurley, Jarrod R.

    2004-01-01

    Using evolutionary population synthesis, we present integrated spectral energy distributions and absorption-line indices defined by the Lick Observatory image dissector scanner (referred to as Lick/IDS) system, for an extensive set of instantaneous burst single stellar populations (SSPs). The ages of the SSPs are in the range 1-19 Gyr and the metallicities [Fe/H] are in the range -2.3 - 0.2. Our models use the rapid single stellar evolution algorithm of Hurley, Pols and Tout for the stellar e...

  6. Spectral energy distributions of T Tauri stars - disk flaring and limits on accretion

    International Nuclear Information System (INIS)

    Kenyon, S.J.; Hartmann, L.

    1987-01-01

    The Adams et al. (1987) conclusion that much of the IR excess emission in the spectral energy distribution of T Tauri stars arises from reprocessing of stellar radiation by a dusty circumstellar disk is presently supported by analyses conducted in light of various models of these stars' spectra. A low mass reprocessing disk can, however, produce these spectra as well as a massive accretion disk. The detection of possible boundary layer radiation in the optical and near-UV regions poses the strongest limits on accretion rates. Disk accretion in the T Tauri phase does not significantly modify stellar evolution. 85 references

  7. Spectral energy transfer of atmospheric gravity waves through sum and difference nonlinear interactions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, K.M. [Wuhan Univ. (China). School of Electronic Information; Chinese Academey of Sciences, Hefei (China). Key Lab. of Geospace Environment; Embry Riddle Aeronautical Univ., Daytona Beach, FL (United States). Dept. of Physical Science; Ministry of Education, Wuhan (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan (China); Liu, A.Z.; Li, Z. [Embry Riddle Aeronautical Univ., Daytona Beach, FL (United States). Dept. of Physical Science; Zhang, S.D.; Yi, F. [Wuhan Univ. (China). School of Electronic Information; Ministry of Education, Wuhan (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan (China)

    2012-07-01

    Nonlinear interactions of gravity waves are studied with a two-dimensional, fully nonlinear model. The energy exchanges among resonant and near-resonant triads are examined in order to understand the spectral energy transfer through interactions. The results show that in both resonant and near-resonant interactions, the energy exchange between two high frequency waves is strong, but the energy transfer from large to small vertical scale waves is rather weak. This suggests that the energy cascade toward large vertical wavenumbers through nonlinear interaction is inefficient, which is different from the rapid turbulence cascade. Because of considerable energy exchange, nonlinear interactions can effectively spread high frequency spectrum, and play a significant role in limiting wave amplitude growth and transferring energy into higher altitudes. In resonant interaction, the interacting waves obey the resonant matching conditions, and resonant excitation is reversible, while near-resonant excitation is not so. Although near-resonant interaction shows the complexity of match relation, numerical experiments show an interesting result that when sum and difference near-resonant interactions occur between high and low frequency waves, the wave vectors tend to approximately match in horizontal direction, and the frequency of the excited waves is also close to the matching value. (orig.)

  8. The far infrared radiation characteristics for Li2O.Al2O3.4SiO2(LAS) glass-ceramics and transition-metal oxide

    International Nuclear Information System (INIS)

    Huh, Nam Jung; Yang, Joong Sik

    1991-01-01

    The far infrared radiation characteristic for Li 2 O.Al 2 O 3 .4SiO 2 (LAS) glass, the LAS glass-ceramic and sintered transition metal oxides such as CuO, Fe 2 O 3 and Co 3 O 4 , were investigated. LAS glass and LAS glass-ceramic was higher than that of the LAS glass. Heat-treated CuO and Co 3 o 4 had radiation characteristic of high efficiency infrared radiant, and heat-treated Fe 2 O 3 had radiation characteristic that infrared emissivity decreased in higher was length above 15μm. (Author)

  9. A Different View of Solar Spectral Irradiance Variations: Modeling Total Energy over Six-Month Intervals.

    Science.gov (United States)

    Woods, Thomas N; Snow, Martin; Harder, Jerald; Chapman, Gary; Cookson, Angela

    A different approach to studying solar spectral irradiance (SSI) variations, without the need for long-term (multi-year) instrument degradation corrections, is examining the total energy of the irradiance variation during 6-month periods. This duration is selected because a solar active region typically appears suddenly and then takes 5 to 7 months to decay and disperse back into the quiet-Sun network. The solar outburst energy, which is defined as the irradiance integrated over the 6-month period and thus includes the energy from all phases of active region evolution, could be considered the primary cause for the irradiance variations. Because solar cycle variation is the consequence of multiple active region outbursts, understanding the energy spectral variation may provide a reasonable estimate of the variations for the 11-year solar activity cycle. The moderate-term (6-month) variations from the Solar Radiation and Climate Experiment (SORCE) instruments can be decomposed into positive (in-phase with solar cycle) and negative (out-of-phase) contributions by modeling the variations using the San Fernando Observatory (SFO) facular excess and sunspot deficit proxies, respectively. These excess and deficit variations are fit over 6-month intervals every 2 months over the mission, and these fitted variations are then integrated over time for the 6-month energy. The dominant component indicates which wavelengths are in-phase and which are out-of-phase with solar activity. The results from this study indicate out-of-phase variations for the 1400 - 1600 nm range, with all other wavelengths having in-phase variations.

  10. Critically Evaluated Energy Levels, Spectral Lines, Transition Probabilities, and Intensities of Singly Ionized Vanadium (V ii)

    Energy Technology Data Exchange (ETDEWEB)

    Saloman, Edward B. [Dakota Consulting, Inc., 1110 Bonifant Street, Suite 310, Silver Spring, MD 20910 (United States); Kramida, Alexander [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)

    2017-08-01

    The energy levels, observed spectral lines, and transition probabilities of singly ionized vanadium, V ii, have been compiled. The experimentally derived energy levels belong to the configurations 3 d {sup 4}, 3 d {sup 3} ns ( n  = 4, 5, 6), 3 d {sup 3} np , and 3 d {sup 3} nd ( n  = 4, 5), 3 d {sup 3}4 f , 3 d {sup 2}4 s {sup 2}, and 3 d {sup 2}4 s 4 p . Also included are values for some forbidden lines that may be of interest to the astrophysical community. Experimental Landé g -factors and leading percentages for the levels are included when available, as well as Ritz wavelengths calculated from the energy levels. Wavelengths and transition probabilities are reported for 3568 and 1896 transitions, respectively. From the list of observed wavelengths, 407 energy levels are determined. The observed intensities, normalized to a common scale, are provided. From the newly optimized energy levels, a revised value for the ionization energy is derived, 118,030(60) cm{sup −1}, corresponding to 14.634(7) eV. This is 130 cm{sup −1} higher than the previously recommended value from Iglesias et al.

  11. Determination of the Spectral Index in the Fission Spectrum Energy Regime

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Amy Sarah [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-16

    Neutron reaction cross sections play a vital role in tracking the production and destruction of isotopes exposed to neutron fluence. They are central to the process of reconciling the initial and final atom inventories. Measurements of irradiated samples by radiochemical methods in tangent with an algorithm are used to evaluate the fluence a sample is exposed to over the course of the irradiation. This algorithm is the Isotope Production Code (IPC) created and used by the radiochemistry data assessment team at Los Alamos National Laboratory (LANL). An integral result is calculated by varying the total neutron fluence seen by a sample. A sample, irradiated in a critical assembly, will be exposed to a unique neutron flux defined by the neutron source and distance of the sample from the source. Neutron cross sections utilized are a function of the hardness of the neutron spectrum at the location of irradiation. A spectral index is used an indicator of the hardness of the neutron spectrum. Cross sections fit forms applied in IPC are collapsed from a LANL 30-group energy structure. Several decades of research and development have been performed to formalize the current IPC cross section library. Basis of the current fission spectrum neutron reaction cross section library is rooted in critical assembly experiments performed from the 1950’s through the early 1970’s at LANL. The focus of this report is development of the spectral index used an indicator of the hardness of the neutron spectrum in the fission spectrum energy regime.

  12. Planck Early Results. XV. Spectral Energy Distributions and Radio Continuum Spectra of Northern Extragalactic Radio Sources

    Science.gov (United States)

    Aatrokoski, J.; Ade, P. A. R.; Aghanim, N.; Aller, H. D.; Aller, M. F.; Angelakis, E.; Amaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; hide

    2011-01-01

    Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources. based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multi frequency data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase of development, shape the radio spectra as they move in the relativistic jet. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed, with an emphasis on proper. physical modelling of the synchrotron bump using multiple components. Planck ERCSC data also suggest that the original accelerated electron energy spectrum could be much harder than commonly thought, with power-law index around 1.5 instead of the canonical 2.5. The implications of this are discussed for the acceleration mechanisms effective in blazar shock. Furthermore in many cases the Planck data indicate that gamma-ray emission must originate in the same shocks that produce the radio emission.

  13. Spectral Characterization of the Wave Energy Resource for Puerto Rico (PR) and the United States Virgin Islands (USVI)

    Science.gov (United States)

    Garcia, C. G.; Canals, M.; Irizarry, A. A.

    2016-02-01

    Nowadays a significant amount of wave energy assessments have taken place due to the development of the ocean energy markets worldwide. Energy contained in surface gravity waves is scattered along frequency components that can be described using wave spectra. Correspondingly, characterization and quantification of harvestable wave energy is inherently dictated by the nature of the two-dimensional wave spectrum. The present study uses spectral wave data from the operational SWAN-based CariCOOS Nearshore Wave Model to evaluate the capture efficiency of multiple wave energy converters (WEC). This study revolves around accurately estimating available wave energy as a function of varying spectral distributions, effectively providing a detailed insight concerning local wave conditions for PR and USVI and the resulting available-energy to generated-power ratio. Results in particular, provide a comprehensive characterization of three years' worth of SWAN-based datasets by outlining where higher concentrations of wave energy are localized in the spectrum. Subsequently, the aforementioned datasets were processed to quantify the amount of energy incident on two proposed sites located in PR and USVI. Results were largely influenced by local trade wind activity, which drive predominant sea states, and the amount of North-Atlantic swells that propagate towards the region. Each wave event was numerically analyzed in the frequency domain to evaluate the capacity of a WEC to perform under different spectral distribution scenarios, allowing for a correlation between electrical power output and spectral energy distribution to be established.

  14. Energy calibration issues in nuclear resonant vibrational spectroscopy: observing small spectral shifts and making fast calibrations.

    Science.gov (United States)

    Wang, Hongxin; Yoda, Yoshitaka; Dong, Weibing; Huang, Songping D

    2013-09-01

    The conventional energy calibration for nuclear resonant vibrational spectroscopy (NRVS) is usually long. Meanwhile, taking NRVS samples out of the cryostat increases the chance of sample damage, which makes it impossible to carry out an energy calibration during one NRVS measurement. In this study, by manipulating the 14.4 keV beam through the main measurement chamber without moving out the NRVS sample, two alternative calibration procedures have been proposed and established: (i) an in situ calibration procedure, which measures the main NRVS sample at stage A and the calibration sample at stage B simultaneously, and calibrates the energies for observing extremely small spectral shifts; for example, the 0.3 meV energy shift between the 100%-(57)Fe-enriched [Fe4S4Cl4](=) and 10%-(57)Fe and 90%-(54)Fe labeled [Fe4S4Cl4](=) has been well resolved; (ii) a quick-switching energy calibration procedure, which reduces each calibration time from 3-4 h to about 30 min. Although the quick-switching calibration is not in situ, it is suitable for normal NRVS measurements.

  15. CO-ANALYSIS OF SOLAR MICROWAVE AND HARD X-RAY SPECTRAL EVOLUTIONS. I. IN TWO FREQUENCY OR ENERGY RANGES

    International Nuclear Information System (INIS)

    Song Qiwu; Huang Guangli; Nakajima, Hiroshi

    2011-01-01

    Solar microwave and hard X-ray spectral evolutions are co-analyzed in the 2000 June 10 and 2002 April 10 flares, and are simultaneously observed by the Owens-Valley Solar Array in the microwave band and by Yohkoh/Hard X-ray Telescope or RHESSI in the hard X-ray band, with multiple subpeaks in their light curves. The microwave and hard X-ray spectra are fitted by a power law in two frequency ranges of the optical thin part and two photon energy ranges, respectively. Similar to an earlier event in Shao and Huang, the well-known soft-hard-soft pattern of the lower energy range changed to the hard-soft-hard (HSH) pattern of the higher energy range during the spectral evolution of each subpeak in both hard X-ray flares. This energy dependence is actually supported by a positive correlation between the overall light curves and spectral evolution in the lower energy range, while it becomes an anti-correlation in the higher energy range. Regarding microwave data, the HSH pattern appears in the spectral evolution of each subpeak in the lower frequency range, which is somewhat similar to Huang and Nakajima. However, it returns back to the well-known pattern of soft-hard-harder for the overall spectral evolution in the higher frequency range of both events. This frequency dependence is confirmed by an anti-correlation between the overall light curves and spectral evolution in the lower frequency range, but it becomes a positive correlation in the higher frequency range. The possible mechanisms are discussed, respectively, for reasons why hard X-ray and microwave spectral evolutions have different patterns in different energy and frequency intervals.

  16. Analysis of spectral effects on the energy yield of different PV (photovoltaic) technologies: The case of four specific sites

    International Nuclear Information System (INIS)

    Alonso-Abella, M.; Chenlo, F.; Nofuentes, G.; Torres-Ramírez, M.

    2014-01-01

    This work is aimed at looking into the impact of the solar spectrum distribution on the energy yield of some PV (photovoltaic) materials on both monthly and annual time scales. The relative spectral responses of eight different PV solar cells – representative of each considered technology – have been selected. Modeling solar spectra in four sites located in the north hemisphere together with a 12-month experimental campaign in which spectral irradiances were periodically recorded in two of these sites located in Spain have provided highly interesting results. Regardless of the site, the considered amorphous silicon and cadmium telluride PV cells experience the most noticeable modeled and experimental variations of their monthly spectral gains, whilst flatter seasonal ones are identified in the remaining considered PV technologies. Thus, the maximum monthly variations of these spectral gains take place in the a-Si PV cell, ranging from −16% (winter) to 4% (summer) in Stuttgart. Anyway, the monthly spread of the spectral effects decreases as the latitude of the site does. Last, the impact of the solar spectrum distribution is remarkably reduced when the period of integration is enlarged up to a year. In fact, annual spectral gains keep below 2.2% for all the studied technologies and sites. - Highlights: • Monthly and annual spectral effects on eight different PV (photovoltaic) technologies studied. • Modeled spectra in four sites combined with relative spectral responses. • Measured spectra (12 months) in two sites combined with relative spectral responses. • Higher bandgap technologies: noticeable monthly variations in their spectral gains. • Annual spectral gains keep below 2.2% for all the studied technologies and sites

  17. Toward accurate prediction of potential energy surfaces and the spectral density of hydrogen bonded systems

    International Nuclear Information System (INIS)

    Rekik, Najeh

    2014-01-01

    Despite the considerable progress made in quantum theory and computational methods, detailed descriptions of the potential energy surfaces of hydrogen-bonded systems have not yet been achieved. In addition, the hydrogen bond (H-bond) itself is still so poorly understood at the fundamental level that it remains unclear exactly what geometry constitutes a “real” H-bond. Therefore, in order to investigate features essential for hydrogen bonded complexes, a simple, efficient, and general method for calculating matrix elements of vibrational operators capable of describing the stretching modes and the H-bond bridges of hydrogen-bonded systems is proposed. The derived matrix elements are simple and computationally easy to evaluate, which makes the method suitable for vibrational studies of multiple-well potentials. The method is illustrated by obtaining potential energy surfaces for a number of two-dimensional systems with repulsive potentials chosen to be in Gaussian form for the stretching mode and of the Morse-type for the H-bond bridge dynamics. The forms of potential energy surfaces of weak and strong hydrogen bonds are analyzed by varying the asymmetry of the Gaussian potential. Moreover, the choice and applicability of the selected potential for the stretching mode and comparison with other potentials used in the area of hydrogen bond research are discussed. The approach for the determination of spectral density has been constructed in the framework of the linear response theory for which spectral density is obtained by Fourier transform of the autocorrelation function of the dipole moment operator of the fast mode. The approach involves anharmonic coupling between the high frequency stretching vibration (double well potential) and low-frequency donor-acceptor stretching mode (Morse potential) as well as the electrical anharmonicity of the dipole moment operator of the fast mode. A direct relaxation mechanism is incorporated through a time decaying exponential

  18. Virtual Non-Contrast CT Using Dual-Energy Spectral CT: Feasibility of Coronary Artery Calcium Scoring

    OpenAIRE

    Song, Inyoung; Yi, Jeong Geun; Park, Jeong Hee; Kim, Sung Mok; Lee, Kyung Soo; Chung, Myung Jin

    2016-01-01

    Objective To evaluate the feasibility of coronary artery calcium scoring based on three virtual noncontrast-enhanced (VNC) images derived from single-source spectral dual-energy CT (DECT) as compared with true noncontrast-enhanced (TNC) images. Materials and Methods This prospective study was conducted with the approval of our Institutional Review Board. Ninety-seven patients underwent noncontrast CT followed by contrast-enhanced chest CT using single-source spectral DECT. Iodine eliminated V...

  19. COMBINED ANALYSIS OF IMAGES AND SPECTRAL ENERGY DISTRIBUTIONS OF TAURUS PROTOSTARS

    International Nuclear Information System (INIS)

    Gramajo, Luciana V.; Gomez, Mercedes; Whitney, Barbara A.; Robitaille, Thomas P.

    2010-01-01

    We present an analysis of spectral energy distributions (SEDs), near- and mid-infrared images, and Spitzer spectra of eight embedded Class I/II objects in the Taurus-Auriga molecular cloud. The initial model for each source was chosen using the grid of young stellar objects (YSOs) and SED fitting tool of Robitaille et al. Then the models were refined using the radiative transfer code of Whitney et al. to fit both the spectra and the infrared images of these objects. In general, our models agree with previous published analyses. However, our combined models should provide more reliable determinations of the physical and geometrical parameters since they are derived from SEDs, including the Spitzer spectra, covering the complete spectral range; and high-resolution near-infrared and Spitzer IRAC images. The combination of SED and image modeling better constrains the different components (central source, disk, envelope) of the YSOs. Our derived luminosities are higher, on average, than previous estimates because we account for the viewing angles (usually nearly edge-on) of most of the sources. Our analysis suggests that the standard rotating collapsing protostar model with disks and bipolar cavities works well for the analyzed sample of objects in the Taurus molecular cloud.

  20. A spectral chart method for estimating the mean turbulent kinetic energy dissipation rate

    Science.gov (United States)

    Djenidi, L.; Antonia, R. A.

    2012-10-01

    We present an empirical but simple and practical spectral chart method for determining the mean turbulent kinetic energy dissipation rate DNS spectra, points to this scaling being also valid at small Reynolds numbers, provided effects due to inhomogeneities in the flow are negligible. The methods avoid the difficulty associated with estimating time or spatial derivatives of the velocity fluctuations. It also avoids using the second hypothesis of K41, which implies the existence of a -5/3 inertial subrange only when the Taylor microscale Reynods number R λ is sufficiently large. The method is in fact applied to the lower wavenumber end of the dissipative range thus avoiding most of the problems due to inadequate spatial resolution of the velocity sensors and noise associated with the higher wavenumber end of this range.The use of spectral data (30 ≤ R λ ≤ 400) in both passive and active grid turbulence, a turbulent mixing layer and the turbulent wake of a circular cylinder indicates that the method is robust and should lead to reliable estimates of < \\varepsilon rangle in flows or flow regions where the first similarity hypothesis should hold; this would exclude, for example, the region near a wall.

  1. THE ULTRAVIOLET-TO-MID-INFRARED SPECTRAL ENERGY DISTRIBUTION OF WEAK EMISSION LINE QUASARS

    International Nuclear Information System (INIS)

    Lane, Ryan A.; Shemmer, Ohad; Diamond-Stanic, Aleksandar M.; Fan Xiaohui; Anderson, Scott F.; Brandt, W. N.; Schneider, Donald P.; Plotkin, Richard M.; Richards, Gordon T.; Strauss, Michael A.

    2011-01-01

    We present Spitzer Space Telescope photometry of 18 Sloan Digital Sky Survey (SDSS) quasars at 2.7 ≤ z ≤ 5.9 which have weak or undetectable high-ionization emission lines in their rest-frame ultraviolet (UV) spectra (hereafter weak-lined quasars, or WLQs). The Spitzer data are combined with SDSS spectra and ground-based, near-infrared (IR) photometry of these sources to produce a large inventory of spectral energy distributions (SEDs) of WLQs across the rest-frame ∼0.1-5 μm spectral band. The SEDs of our sources are inconsistent with those of BL Lacertae objects which are dominated by synchrotron emission due to a jet aligned close to our line of sight, but are consistent with the SED of ordinary quasars with similar luminosities and redshifts that exhibit a near-to-mid-IR 'bump', characteristic of hot dust emission. This indicates that broad emission lines in WLQs are intrinsically weak, rather than suffering continuum dilution from a jet, and that such sources cannot be selected efficiently from traditional photometric surveys.

  2. THE ULTRAVIOLET-TO-MID-INFRARED SPECTRAL ENERGY DISTRIBUTION OF WEAK EMISSION LINE QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Ryan A.; Shemmer, Ohad [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Diamond-Stanic, Aleksandar M. [Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA 92093 (United States); Fan Xiaohui [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Anderson, Scott F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Brandt, W. N.; Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Plotkin, Richard M. [Astronomical Institute ' Anton Pannekoek' , University of Amsterdam, Science Park 904, NL-1098 XH Amsterdam (Netherlands); Richards, Gordon T. [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Strauss, Michael A., E-mail: RyanLane@my.unt.edu, E-mail: ohad@unt.edu [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544 (United States)

    2011-12-20

    We present Spitzer Space Telescope photometry of 18 Sloan Digital Sky Survey (SDSS) quasars at 2.7 {<=} z {<=} 5.9 which have weak or undetectable high-ionization emission lines in their rest-frame ultraviolet (UV) spectra (hereafter weak-lined quasars, or WLQs). The Spitzer data are combined with SDSS spectra and ground-based, near-infrared (IR) photometry of these sources to produce a large inventory of spectral energy distributions (SEDs) of WLQs across the rest-frame {approx}0.1-5 {mu}m spectral band. The SEDs of our sources are inconsistent with those of BL Lacertae objects which are dominated by synchrotron emission due to a jet aligned close to our line of sight, but are consistent with the SED of ordinary quasars with similar luminosities and redshifts that exhibit a near-to-mid-IR 'bump', characteristic of hot dust emission. This indicates that broad emission lines in WLQs are intrinsically weak, rather than suffering continuum dilution from a jet, and that such sources cannot be selected efficiently from traditional photometric surveys.

  3. Differential diagnosis between benign and malignant pleural effusion with dual-energy spectral CT.

    Science.gov (United States)

    Zhang, Xirong; Duan, Haifeng; Yu, Yong; Ma, Chunling; Ren, Zhanli; Lei, Yuxin; He, Taiping; Zhang, Ming

    2018-01-01

    of 100% and specificity of 71.4% with area-under-curve of 0.933 for differentiating benign from malignant effusion. The CT value measurement at both high and low energy levels and the effective atomic number obtained in a single spectral CT scan can assist the differential diagnosis of benign from malignant pleural effusion.Combining them with patient age and disease history can further improve diagnostic performance. Clinical findings and Spectral CT imaging can provide significant evidences about the nature of pleural effusion.

  4. The spectral energy distributions of isolated neutron stars in the resonant cyclotron scattering model

    Science.gov (United States)

    Tong, Hao; Xu, Renxin

    2013-03-01

    The X-ray dim isolated neutron stars (XDINSs) are peculiar pulsar-like objects, characterized by their very well Planck-like spectrum. In studying their spectral energy distributions, the optical/UV excess is a long standing problem. Recently, Kaplan et al. (2011) have measured the optical/UV excess for all seven sources, which is understandable in the resonant cyclotron scattering (RCS) model previously addressed. The RCS model calculations show that the RCS process can account for the observed optical/UV excess for most sources. The flat spectrum of RX J2143.0+0654 may due to contribution from bremsstrahlung emission of the electron system in addition to the RCS process.

  5. Optimized Energy Efficiency and Spectral Efficiency Resource Allocation Strategies for Phantom Cellular Networks

    KAUST Repository

    Abdelhady, Amr, M.; Amin, Osama; Alouini, Mohamed-Slim

    2016-01-01

    Multi-teir hetrogeneous networks have become an essential constituent for next generation cellular networks. Meanwhile, energy efficiency (EE) has been considered a critical design criterion along with the traditional spectral efficiency (SE) metric. In this context, we study power and spectrum allocation for the recently proposed two-teir architecture known as Phantom cellular networks. The optimization framework includes both EE and SE, where we propose an algorithm that computes the SE and EE resource allocation for Phantom cellular networks. Then, we compare the performance of both design strategies versus the number of users, and the ration of Phantom cellresource blocks to the total number or resource blocks. We aim to investigate the effect of some system parameters to acheive improved SE or EE performance at a non-significant loss in EE or SE performance, respectively. It was found that the system parameters can be tuned so that the EE solution does not yield a significant loss in the SE performance.

  6. Energy and spectral efficiency analysis for selective ARQ multi-channel systems

    KAUST Repository

    Shafique, Taniya

    2017-07-31

    In this paper, we develop selective retransmission schemes for multiple-channel systems. The proposed schemes are selective automatic repeat request with fixed bandwidth (SARQ-FB), selective chase combining with fixed bandwidth (SCC-FB) and selective automatic repeat request with variable bandwidth (SARQ-VB). The main objective of the proposed schemes is to use the available power and bandwidth budget effectively along with the selective retransmission to deliver the required data successfully within a limited number of transmissions. To investigate the performance of each scheme, we first analyze the average spectral and energy efficiency and derive closed form expressions for each scheme. Then, we compare the EE and SE of each scheme through numerical results.

  7. A dust spectral energy distribution model with hierarchical Bayesian inference - I. Formalism and benchmarking

    Science.gov (United States)

    Galliano, Frédéric

    2018-05-01

    This article presents a new dust spectral energy distribution (SED) model, named HerBIE, aimed at eliminating the noise-induced correlations and large scatter obtained when performing least-squares fits. The originality of this code is to apply the hierarchical Bayesian approach to full dust models, including realistic optical properties, stochastic heating, and the mixing of physical conditions in the observed regions. We test the performances of our model by applying it to synthetic observations. We explore the impact on the recovered parameters of several effects: signal-to-noise ratio, SED shape, sample size, the presence of intrinsic correlations, the wavelength coverage, and the use of different SED model components. We show that this method is very efficient: the recovered parameters are consistently distributed around their true values. We do not find any clear bias, even for the most degenerate parameters, or with extreme signal-to-noise ratios.

  8. Optimized Energy Efficiency and Spectral Efficiency Resource Allocation Strategies for Phantom Cellular Networks

    KAUST Repository

    Abdelhady, Amr, M.

    2016-01-06

    Multi-teir hetrogeneous networks have become an essential constituent for next generation cellular networks. Meanwhile, energy efficiency (EE) has been considered a critical design criterion along with the traditional spectral efficiency (SE) metric. In this context, we study power and spectrum allocation for the recently proposed two-teir architecture known as Phantom cellular networks. The optimization framework includes both EE and SE, where we propose an algorithm that computes the SE and EE resource allocation for Phantom cellular networks. Then, we compare the performance of both design strategies versus the number of users, and the ration of Phantom cellresource blocks to the total number or resource blocks. We aim to investigate the effect of some system parameters to acheive improved SE or EE performance at a non-significant loss in EE or SE performance, respectively. It was found that the system parameters can be tuned so that the EE solution does not yield a significant loss in the SE performance.

  9. Virtual non-contrast CT using dual energy spectral CT: Feasibility of coronary artery calcium scoring

    International Nuclear Information System (INIS)

    Song, In Young; Yi, Jeong Geun; Park, Jeong Hee; Lee, Sung Mok; Lee, Kyung Soo; Chung, Myung Jin

    2016-01-01

    To evaluate the feasibility of coronary artery calcium scoring based on three virtual noncontrast-enhanced (VNC) images derived from single-source spectral dual-energy CT (DECT) as compared with true noncontrast-enhanced (TNC) images. This prospective study was conducted with the approval of our Institutional Review Board. Ninety-seven patients underwent noncontrast CT followed by contrast-enhanced chest CT using single-source spectral DECT. Iodine eliminated VNC images were reconstructed using two kinds of 2-material decomposition algorithms (material density iodine-water pair [MDW], material density iodine-calcium pair [MDC]) and a material suppressed algorithm (material suppressed iodine [MSI]). Two readers independently quantified calcium on VNC and TNC images. The Spearman correlation coefficient test and Bland-Altman method were used for statistical analyses. Coronary artery calcium scores from all three VNC images showed excellent correlation with those from the TNC images (Spearman's correlation coefficient [ρ] = 0.94, 0.88, and 0.89 for MDW, MDC, and MSI, respectively; p < 0.001 for all pairs). Measured coronary calcium volumes from VNC images also correlated well with those from TNC images (ρ = 0.92, 0.87, and 0.91 for MDW, MDC, and MSI, respectively; p < 0.001 for all pairs). Among the three VNC images, coronary calcium from MDW correlated best with that from TNC. The coronary artery calcium scores and volumes were significantly lower from the VNC images than from the TNC images (p < 0.001 for all pairs). The use of VNC images from contrast-enhanced CT using dual-energy material decomposition/suppression is feasible for coronary calcium scoring. The absolute value from VNC tends to be smaller than that from TNC

  10. Virtual non-contrast CT using dual energy spectral CT: Feasibility of coronary artery calcium scoring

    Energy Technology Data Exchange (ETDEWEB)

    Song, In Young; Yi, Jeong Geun; Park, Jeong Hee [Dept. of Radiology, Konkuk University School of Medicine, Seoul (Korea, Republic of); Lee, Sung Mok; Lee, Kyung Soo; Chung, Myung Jin [Dept. of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2016-06-15

    To evaluate the feasibility of coronary artery calcium scoring based on three virtual noncontrast-enhanced (VNC) images derived from single-source spectral dual-energy CT (DECT) as compared with true noncontrast-enhanced (TNC) images. This prospective study was conducted with the approval of our Institutional Review Board. Ninety-seven patients underwent noncontrast CT followed by contrast-enhanced chest CT using single-source spectral DECT. Iodine eliminated VNC images were reconstructed using two kinds of 2-material decomposition algorithms (material density iodine-water pair [MDW], material density iodine-calcium pair [MDC]) and a material suppressed algorithm (material suppressed iodine [MSI]). Two readers independently quantified calcium on VNC and TNC images. The Spearman correlation coefficient test and Bland-Altman method were used for statistical analyses. Coronary artery calcium scores from all three VNC images showed excellent correlation with those from the TNC images (Spearman's correlation coefficient [ρ] = 0.94, 0.88, and 0.89 for MDW, MDC, and MSI, respectively; p < 0.001 for all pairs). Measured coronary calcium volumes from VNC images also correlated well with those from TNC images (ρ = 0.92, 0.87, and 0.91 for MDW, MDC, and MSI, respectively; p < 0.001 for all pairs). Among the three VNC images, coronary calcium from MDW correlated best with that from TNC. The coronary artery calcium scores and volumes were significantly lower from the VNC images than from the TNC images (p < 0.001 for all pairs). The use of VNC images from contrast-enhanced CT using dual-energy material decomposition/suppression is feasible for coronary calcium scoring. The absolute value from VNC tends to be smaller than that from TNC.

  11. Differentiation of urinary calculi with dual energy CT: effect of spectral shaping by high energy tin filtration.

    Science.gov (United States)

    Thomas, Christoph; Krauss, Bernhard; Ketelsen, Dominik; Tsiflikas, Ilias; Reimann, Anja; Werner, Matthias; Schilling, David; Hennenlotter, Jörg; Claussen, Claus D; Schlemmer, Heinz-Peter; Heuschmid, Martin

    2010-07-01

    In dual energy (DE) computed tomography (CT), spectral shaping by additional filtration of the high energy spectrum can theoretically improve dual energy contrast. The aim of this in vitro study was to examine the influence of an additional tin filter for the differentiation of human urinary calculi by dual energy CT. A total of 36 pure human urinary calculi (uric acid, cystine, calciumoxalate monohydrate, calciumoxalate dihydrate, carbonatapatite, brushite, average diameter 10.5 mm) were placed in a phantom and imaged with 2 dual source CT scanners. One scanner was equipped with an additional tin (Sn) filter. Different combinations of tube voltages (140/80 kV, 140/100 kV, Sn140/100 kV, Sn140/80 kV, with Sn140 referring to 140 kV with the tin filter) were applied. Tube currents were adapted to yield comparable dose indices. Low- and high energy images were reconstructed. The calculi were segmented semiautomatically in the datasets and DE ratios (attenuation@low_kV/attenuation@high_kV) and were calculated for each calculus. DE contrasts (DE-ratio_material1/DE-ratio_material2) were computed for uric acid, cystine and calcified calculi and compared between the combinations of tube voltages. Using exclusively DE ratios, all uric acid, cystine and calcified calculi (as a group) could be differentiated in all protocols; the calcified calculi could not be differentiated among each other in any examination protocol. The highest DE ratios and DE contrasts were measured for the Sn140/80 protocol (53%-62% higher DE contrast than in the 140/80 kV protocol without additional filtration). The DE ratios and DE contrasts of the 80/140 kV and 100/Sn140 kV protocols were comparable. Uric acid, cystine and calcified calculi could be reliably differentiated by any of the protocols. A dose-neutral gain of DE contrast was found in the Sn-filter protocols, which might improve the differentiation of smaller calculi (Sn140/80 kV) and improve image quality and calculi differentiation in

  12. Spectral-Efficiency - Illumination Pareto Front for Energy Harvesting Enabled VLC System

    KAUST Repository

    Abdelhady, Amr Mohamed Abdelaziz

    2017-12-13

    The continuous improvement in optical energy harvesting devices motivates visible light communication (VLC) system developers to utilize such available free energy sources. An outdoor VLC system is considered where an optical base station sends data to multiple users that are capable of harvesting the optical energy. The proposed VLC system serves multiple users using time division multiple access (TDMA) with unequal time and power allocation, which are allocated to improve the system performance. The adopted optical system provides users with illumination and data communication services. The outdoor optical design objective is to maximize the illumination, while the communication design objective is to maximize the spectral efficiency (SE). The design objectives are shown to be conflicting, therefore, a multiobjective optimization problem is formulated to obtain the Pareto front performance curve for the proposed system. To this end, the marginal optimization problems are solved first using low complexity algorithms. Then, based on the proposed algorithms, a low complexity algorithm is developed to obtain an inner bound of the Pareto front for the illumination-SE tradeoff. The inner bound for the Pareto-front is shown to be close to the optimal Pareto-frontier via several simulation scenarios for different system parameters.

  13. Internal rotation of 1-Aryl-3,3-dialkyltriazenes. Comparison of semiempirical molecular orbital calculations with far-infrared, Raman, and NMR spectroscopic results

    International Nuclear Information System (INIS)

    Panitz, J.C.; Lippert, T.; Wokaun, A.

    1994-01-01

    PM3 and AM1 semiempirical molecular orbital techniques are used to establish a model for internal rotation about the N 2 -N 3 axis of 1-aryl-3,3-dialkyltriazines. The PM3 method is satisfactory for obtaining agreement between the experimental and calculated results, but the AM1 method has an artifact in the potential energy curve of internal rotation about the N 2 -N 3 axis. 24 refs., 6 figs., 5 tabs

  14. Spectral heterogeneity and carotenoid-to-bacteriochlorophyll energy transfer in LH2 light-harvesting complexes from Allochromatium vinosum.

    Science.gov (United States)

    Magdaong, Nikki M; LaFountain, Amy M; Hacking, Kirsty; Niedzwiedzki, Dariusz M; Gibson, George N; Cogdell, Richard J; Frank, Harry A

    2016-02-01

    Photosynthetic organisms produce a vast array of spectral forms of antenna pigment-protein complexes to harvest solar energy and also to adapt to growth under the variable environmental conditions of light intensity, temperature, and nutrient availability. This behavior is exemplified by Allochromatium (Alc.) vinosum, a photosynthetic purple sulfur bacterium that produces different types of LH2 light-harvesting complexes in response to variations in growth conditions. In the present work, three different spectral forms of LH2 from Alc. vinosum, B800-820, B800-840, and B800-850, were isolated, purified, and examined using steady-state absorption and fluorescence spectroscopy, and ultrafast time-resolved absorption spectroscopy. The pigment composition of the LH2 complexes was analyzed by high-performance liquid chromatography, and all were found to contain five carotenoids: lycopene, anhydrorhodovibrin, spirilloxanthin, rhodopin, and rhodovibrin. Spectral reconstructions of the absorption and fluorescence excitation spectra based on the pigment composition revealed significantly more spectral heterogeneity in these systems compared to LH2 complexes isolated from other species of purple bacteria. The data also revealed the individual carotenoid-to-bacteriochlorophyll energy transfer efficiencies which were correlated with the kinetic data from the ultrafast transient absorption spectroscopic experiments. This series of LH2 complexes allows a systematic exploration of the factors that determine the spectral properties of the bound pigments and control the rate and efficiency of carotenoid-to-bacteriochlorophyll energy transfer.

  15. Spectral and Energy Efficiencies in mmWave Cellular Networks for Optimal Utilization

    Directory of Open Access Journals (Sweden)

    Abdulbaset M. Hamed

    2018-01-01

    Full Text Available Millimeter wave (mmWave spectrum has been proposed for use in commercial cellular networks to relieve the already severely congested microwave spectrum. Thus, the design of an efficient mmWave cellular network has gained considerable importance and has to take into account regulations imposed by government agencies with regard to global warming and sustainable development. In this paper, a dense mmWave hexagonal cellular network with each cell consisting of a number of smaller cells with their own Base Stations (BSs is presented as a solution to meet the increasing demand for a variety of high data rate services and growing number of users of cellular networks. Since spectrum and power are critical resources in the design of such a network, a framework is presented that addresses efficient utilization of these resources in mmWave cellular networks in the 28 and 73 GHz bands. These bands are already an integral part of well-known standards such as IEEE 802.15.3c, IEEE 802.11ad, and IEEE 802.16.1. In the analysis, a well-known accurate mmWave channel model for Line of Sight (LOS and Non-Line of Sight (NLOS links is used. The cellular network is analyzed in terms of spectral efficiency, bit/s, energy efficiency, bit/J, area spectral efficiency, bit/s/m2, area energy efficiency, bit/J/m2, and network latency, s/bit. These efficiency metrics are illustrated, using Monte Carlo simulation, as a function of Signal-to-Noise Ratio (SNR, channel model parameters, user distance from BS, and BS transmission power. The efficiency metrics for optimum deployment of cellular networks in 28 and 73 GHz bands are identified. Results show that 73 GHz band achieves better spectrum efficiency and the 28 GHz band is superior in terms of energy efficiency. It is observed that while the latter band is expedient for indoor networks, the former band is appropriate for outdoor networks.

  16. FERMI LARGE AREA TELESCOPE OBSERVATIONS OF MARKARIAN 421: THE MISSING PIECE OF ITS SPECTRAL ENERGY DISTRIBUTION

    International Nuclear Information System (INIS)

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Buehler, R.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bonamente, E.; Bouvier, A.; Brigida, M.; Bruel, P.

    2011-01-01

    We report on the γ-ray activity of the high-synchrotron-peaked BL Lacertae object Markarian 421 (Mrk 421) during the first 1.5 years of Fermi operation, from 2008 August 5 to 2010 March 12. We find that the Large Area Telescope (LAT) γ-ray spectrum above 0.3 GeV can be well described by a power-law function with photon index Γ = 1.78 ± 0.02 and average photon flux F(> 0.3 GeV) = (7.23 ± 0.16) x 10 -8 ph cm -2 s -1 . Over this time period, the Fermi-LAT spectrum above 0.3 GeV was evaluated on seven-day-long time intervals, showing significant variations in the photon flux (up to a factor ∼3 from the minimum to the maximum flux) but mild spectral variations. The variability amplitude at X-ray frequencies measured by RXTE/ASM and Swift/BAT is substantially larger than that in γ-rays measured by Fermi-LAT, and these two energy ranges are not significantly correlated. We also present the first results from the 4.5 month long multifrequency campaign on Mrk 421, which included the VLBA, Swift, RXTE, MAGIC, the F-GAMMA, GASP-WEBT, and other collaborations and instruments that provided excellent temporal and energy coverage of the source throughout the entire campaign (2009 January 19 to 2009 June 1). During this campaign, Mrk 421 showed a low activity at all wavebands. The extensive multi-instrument (radio to TeV) data set provides an unprecedented, complete look at the quiescent spectral energy distribution (SED) for this source. The broadband SED was reproduced with a leptonic (one-zone synchrotron self-Compton) and a hadronic model (synchrotron proton blazar). Both frameworks are able to describe the average SED reasonably well, implying comparable jet powers but very different characteristics for the blazar emission site.

  17. Star formation relations and CO spectral line energy distributions across the J-ladder and redshift

    Energy Technology Data Exchange (ETDEWEB)

    Greve, T. R. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Leonidaki, I.; Xilouris, E. M. [Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, GR-15236 Penteli (Greece); Weiß, A.; Henkel, C. [Max-Planck-Institut fur Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Zhang, Z.-Y. [UK Astronomy Technology Centre, Science and Technology Facilities Council, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Van der Werf, P.; Meijerink, R. [Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA Leiden (Netherlands); Aalto, S. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Observatory, 43994 Onsala (Sweden); Armus, L.; Díaz-Santos, T. [Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States); Evans, A. S. [Astronomy Department, University of Virginia Charlottesville, VA 22904 (United States); Fischer, J. [Naval Research Laboratory, Remote Sensing Division, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Gao, Y. [Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008 (China); González-Alfonso, E. [Universidad de Alcala de Henares, Departamento de Fśica, Campus Universitario, E-28871 Alcalá de Henares, Madrid (Spain); Harris, A. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Naylor, D. A. [Institute for Space Imaging Science, Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB T1K 3M4 (Canada); Smith, H. A. [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Spaans, M., E-mail: t.greve@ucl.ac.uk [Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen (Netherlands); and others

    2014-10-20

    We present FIR [50-300 μm]–CO luminosity relations (i.e., log L{sub FIR}=αlog L{sub CO}{sup ′}+β) for the full CO rotational ladder from J = 1-0 up to J = 13-12 for a sample of 62 local (z ≤ 0.1) (Ultra) Luminous Infrared Galaxies (LIRGs; L {sub IR[8-1000} {sub μm]} > 10{sup 11} L {sub ☉}) using data from Herschel SPIRE-FTS and ground-based telescopes. We extend our sample to high redshifts (z > 1) by including 35 submillimeter selected dusty star forming galaxies from the literature with robust CO observations, and sufficiently well-sampled FIR/submillimeter spectral energy distributions (SEDs), so that accurate FIR luminosities can be determined. The addition of luminous starbursts at high redshifts enlarge the range of the FIR–CO luminosity relations toward the high-IR-luminosity end, while also significantly increasing the small amount of mid-J/high-J CO line data (J = 5-4 and higher) that was available prior to Herschel. This new data set (both in terms of IR luminosity and J-ladder) reveals linear FIR–CO luminosity relations (i.e., α ≅ 1) for J = 1-0 up to J = 5-4, with a nearly constant normalization (β ∼ 2). In the simplest physical scenario, this is expected from the (also) linear FIR–(molecular line) relations recently found for the dense gas tracer lines (HCN and CS), as long as the dense gas mass fraction does not vary strongly within our (merger/starburst)-dominated sample. However, from J = 6-5 and up to the J = 13-12 transition, we find an increasingly sublinear slope and higher normalization constant with increasing J. We argue that these are caused by a warm (∼100 K) and dense (>10{sup 4} cm{sup –3}) gas component whose thermal state is unlikely to be maintained by star-formation-powered far-UV radiation fields (and thus is no longer directly tied to the star formation rate). We suggest that mechanical heating (e.g., supernova-driven turbulence and shocks), and not cosmic rays, is the more likely source of energy for

  18. A spectral chart method for estimating the mean turbulent kinetic energy dissipation rate

    Energy Technology Data Exchange (ETDEWEB)

    Djenidi, L.; Antonia, R.A. [The University of Newcastle, School of Engineering, Newcastle, NSW (Australia)

    2012-10-15

    We present an empirical but simple and practical spectral chart method for determining the mean turbulent kinetic energy dissipation rate left angle {epsilon}right angle in a variety of turbulent flows. The method relies on the validity of the first similarity hypothesis of Kolmogorov (C R (Doklady) Acad Sci R R SS, NS 30:301-305, 1941) (or K41) which implies that spectra of velocity fluctuations scale on the kinematic viscosity {nu} and left angle {epsilon}right angle at large Reynolds numbers. However, the evidence, based on the DNS spectra, points to this scaling being also valid at small Reynolds numbers, provided effects due to inhomogeneities in the flow are negligible. The methods avoid the difficulty associated with estimating time or spatial derivatives of the velocity fluctuations. It also avoids using the second hypothesis of K41, which implies the existence of a -5/3 inertial subrange only when the Taylor microscale Reynolds number R{sub {lambda}} is sufficiently large. The method is in fact applied to the lower wavenumber end of the dissipative range thus avoiding most of the problems due to inadequate spatial resolution of the velocity sensors and noise associated with the higher wavenumber end of this range.The use of spectral data (30 {<=} R{sub {lambda}}{<=} 400) in both passive and active grid turbulence, a turbulent mixing layer and the turbulent wake of a circular cylinder indicates that the method is robust and should lead to reliable estimates of left angle {epsilon}right angle in flows or flow regions where the first similarity hypothesis should hold; this would exclude, for example, the region near a wall. (orig.)

  19. Optimized energy of spectral CT for infarct imaging: Experimental validation with human validation.

    Science.gov (United States)

    Sandfort, Veit; Palanisamy, Srikanth; Symons, Rolf; Pourmorteza, Amir; Ahlman, Mark A; Rice, Kelly; Thomas, Tom; Davies-Venn, Cynthia; Krauss, Bernhard; Kwan, Alan; Pandey, Ankur; Zimmerman, Stefan L; Bluemke, David A

    Late contrast enhancement visualizes myocardial infarction, but the contrast to noise ratio (CNR) is low using conventional CT. The aim of this study was to determine if spectral CT can improve imaging of myocardial infarction. A canine model of myocardial infarction was produced in 8 animals (90-min occlusion, reperfusion). Later, imaging was performed after contrast injection using CT at 90 kVp/150 kVpSn. The following reconstructions were evaluated: Single energy 90 kVp, mixed, iodine map, multiple monoenergetic conventional and monoenergetic noise optimized reconstructions. Regions of interest were measured in infarct and remote regions to calculate contrast to noise ratio (CNR) and Bhattacharya distance (a metric of the differentiation between regions). Blinded assessment of image quality was performed. The same reconstruction methods were applied to CT scans of four patients with known infarcts. For animal studies, the highest CNR for infarct vs. myocardium was achieved in the lowest keV (40 keV) VMo images (CNR 4.42, IQR 3.64-5.53), which was superior to 90 kVp, mixed and iodine map (p = 0.008, p = 0.002, p energy in conjunction with noise-optimized monoenergetic post-processing improves CNR of myocardial infarct delineation by approximately 20-25%. Published by Elsevier Inc.

  20. Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Kapińska, A. D.; Staveley-Smith, L.; Meurer, G. R.; For, B.-Q. [International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, 35 Stirling Hwy, WA 6009 (Australia); Crocker, R. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Bhandari, S.; Callingham, J. R.; Gaensler, B. M.; Hancock, P. J.; Lenc, E. [ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO), Sydney NSW (Australia); Hurley-Walker, N.; Seymour, N. [International Centre for Radio Astronomy Research (ICRAR), Curtin University, Bentley, WA 6102 (Australia); Offringa, A. R. [Netherlands Institute for Radio Astronomy (ASTRON), P.O. Box 2, 7990 AA Dwingeloo (Netherlands); Hanish, D. J. [Spitzer Science Center, California Institute of Technology, MC 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Ekers, R. D.; Bell, M. E. [CSIRO Astronomy and Space Science (CASS), P.O. Box 76, Epping, NSW 1710 (Australia); Dwarakanath, K. S. [Raman Research Institute, Bangalore 560080 (India); Hindson, L. [Centre of Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington 6140 (New Zealand); McKinley, B., E-mail: anna.kapinska@uwa.edu.au [School of Physics, The University of Melbourne, Parkville, VIC 3010 (Australia); and others

    2017-03-20

    We present new radio continuum observations of NGC 253 from the Murchison Widefield Array at frequencies between 76 and 227 MHz. We model the broadband radio spectral energy distribution for the total flux density of NGC 253 between 76 MHz and 11 GHz. The spectrum is best described as a sum of a central starburst and extended emission. The central component, corresponding to the inner 500 pc of the starburst region of the galaxy, is best modeled as an internally free–free absorbed synchrotron plasma, with a turnover frequency around 230 MHz. The extended emission component of the spectrum of NGC 253 is best described as a synchrotron emission flattening at low radio frequencies. We find that 34% of the extended emission (outside the central starburst region) at 1 GHz becomes partially absorbed at low radio frequencies. Most of this flattening occurs in the western region of the southeast halo, and may be indicative of synchrotron self-absorption of shock-reaccelerated electrons or an intrinsic low-energy cutoff of the electron distribution. Furthermore, we detect the large-scale synchrotron radio halo of NGC 253 in our radio images. At 154–231 MHz the halo displays the well known X-shaped/horn-like structure, and extends out to ∼8 kpc in the z -direction (from the major axis).

  1. Area Spectral Efficiency and Energy Efficiency Tradeoff in Ultradense Heterogeneous Networks

    Directory of Open Access Journals (Sweden)

    Lanhua Xiang

    2017-01-01

    Full Text Available In order to meet the demand of explosive data traffic, ultradense base station (BS deployment in heterogeneous networks (HetNets as a key technique in 5G has been proposed. However, with the increment of BSs, the total energy consumption will also increase. So, the energy efficiency (EE has become a focal point in ultradense HetNets. In this paper, we take the area spectral efficiency (ASE into consideration and focus on the tradeoff between the ASE and EE in an ultradense HetNet. The distributions of BSs in the two-tier ultradense HetNet are modeled by two independent Poisson point processes (PPPs and the expressions of ASE and EE are derived by using the stochastic geometry tool. The tradeoff between the ASE and EE is formulated as a constrained optimization problem in which the EE is maximized under the ASE constraint, through optimizing the BS densities. It is difficult to solve the optimization problem analytically, because the closed-form expressions of ASE and EE are not easily obtained. Therefore, simulations are conducted to find optimal BS densities.

  2. Constraints on Dark Matter Interactions with Standard Model Particles from Cosmic Microwave Background Spectral Distortions.

    Science.gov (United States)

    Ali-Haïmoud, Yacine; Chluba, Jens; Kamionkowski, Marc

    2015-08-14

    We propose a new method to constrain elastic scattering between dark matter (DM) and standard model particles in the early Universe. Direct or indirect thermal coupling of nonrelativistic DM with photons leads to a heat sink for the latter. This results in spectral distortions of the cosmic microwave background (CMB), the amplitude of which can be as large as a few times the DM-to-photon-number ratio. We compute CMB spectral distortions due to DM-proton, DM-electron, and DM-photon scattering for generic energy-dependent cross sections and DM mass m_{χ}≳1 keV. Using Far-Infrared Absolute Spectrophotometer measurements, we set constraints on the cross sections for m_{χ}≲0.1 MeV. In particular, for energy-independent scattering we obtain σ_{DM-proton}≲10^{-24} cm^{2} (keV/m_{χ})^{1/2}, σ_{DM-electron}≲10^{-27} cm^{2} (keV/m_{χ})^{1/2}, and σ_{DM-photon}≲10^{-39} cm^{2} (m_{χ}/keV). An experiment with the characteristics of the Primordial Inflation Explorer would extend the regime of sensitivity up to masses m_{χ}~1 GeV.

  3. Theoretical estimation and experimental design of high-intensity far-infrared to MM-wave coherent synchrotron radiation generated by short electron bunches at BFEL

    International Nuclear Information System (INIS)

    Zhu Junbiao; Li Yonggui; Xie Jialin

    2000-01-01

    Broadband continuous and high-intensity coherent synchrotron radiation (CSR) emitted from 4 ps electron bunches provided by the 30 MeV RF linac of Beijing FEL is analyzed and numerically calculated using an exact series expansion for the infinite integral of fractional modified Bessel function. CSR in the mm-wave and far-IR to mm-wave regions can be respectively generated by directly using these bunches and by applying those ones compressed to ≤=1 ps. The CSR powers, approximately as 10 8 -10 9 times as the SR ones, in the range from several hundred microwatts to milliwatts are dependent on chosen electron density distribution, wavelength range, and gathering angle. The power produced by rectangular bunches is greater than that generated by Gaussian ones. The shorter the bunch, the stronger the produced CSR, the greater the energy concentrated to the far-IR end. Experiments to generate CSR and measure the bunch length are designed

  4. Vibrational spectroscopy at very high pressures. Part 28. Raman and far-infrared spectra of some complex chlorides A2MCl6 under hydrostatic pressure

    DEFF Research Database (Denmark)

    Adams, David M.; Berg, Rolf W.; Williams, Alan D.

    1981-01-01

    Raman and far-IR mode frequency shifts with pressure have been observed under hydrostatic conditions in a gasketed diamond anvil cell (d.a.c.). Using compressibilities calculated from unit cell constants and lattice energies, Grüneisen parameters gammai have been obtained for all observed modes...... pressure curves for K2SnCl6 and [(CH3)4N]2MCl6 (M=Sn, Te, Pt) are discussed in relation to their structures. Shifts of nu-tilde i with temperature for K2ReCl6 and K2PtCl6 are analyzed into explicit and implicit anharmonic contributions. The Journal of Chemical Physics is copyrighted by The American...

  5. The influence of compressibility on nonlinear spectral energy transfer - Part 2: Effect on hypersonic boundary layer transition

    Science.gov (United States)

    Mittal, Ankita; Girimaji, Sharath

    2017-11-01

    We examine the effect of compressible spectral energy transfer in the nonlinear regime of transition to turbulence of hypersonic boundary layers. The nature of spectral energy transfer between perturbation modes is profoundly influenced by two compressibility mechanisms. First and foremost, the emergence of nonlinear pressure-dilatation mechanism leads to kinetic-internal energy exchange within the perturbation field. Such interchange is absent in incompressible flow as pressure merely reorients the perturbation amplitude vector while conserving kinetic energy. Secondly, the nature of triadic interactions also changes due to variability in density. In this work, we demonstrate that the efficiency of nonlinear spectral energy transfer is diminished in compressible boundary layers. Emergence of new perturbation modes or `broad-banding' of the perturbation field is significantly delayed in comparison to incompressible boundary layer undergoing transition. A significant amount of perturbation energy is transformed to internal energy and thus unavailable for `tripping' the flow into turbulent state. These factors profoundly change the nature of the nonlinear stage of transition in compressible boundary layer leading to delayed onset of full-fledged turbulence.

  6. The Renormalization-Group Method in the Problem on Calculation of the Spectral Energy Density of Fluid Turbulence

    Science.gov (United States)

    Teodorovich, E. V.

    2018-03-01

    In order to find the shape of energy spectrum within the framework of the model of stationary homogeneous isotropic turbulence, the renormalization-group equations, which reflect the Markovian nature of the mechanism of energy transfer along the wavenumber spectrum, are used in addition to the dimensional considerations and the energy balance equation. For the spectrum, the formula depends on three parameters, namely, the wavenumber, which determines the upper boundary of the range of the turbulent energy production, the spectral flux through this boundary, and the fluid kinematic viscosity.

  7. Resource allocation for phantom cellular networks: Energy efficiency vs spectral efficiency

    KAUST Repository

    Abdelhady, Amr Mohamed Abdelaziz; Amin, Osama; Alouini, Mohamed-Slim

    2016-01-01

    Multi-tier heterogeneous networks have become an essential constituent for next generation cellular networks. Mean-while, energy efficiency (EE) has been considered a critical design criterion along with the traditional spectral efficiency (SE) metric. In this context, we study power and spectrum allocation for the recently proposed two-tier network architecture known as phantom cellular networks. The optimization framework includes both EE and SE, where we propose an algorithm that finds the SE and EE resource allocation strategies for phantom cellular networks. Then, we compare the performance of both design strategies versus the number of users, and phantom cells share of the total number of available resource blocks. We aim to investigate the effect of some system parameters to achieve improved SE performance at a non-significant loss in EE performance, or vice versa. It was found that increasing phantom cells share of resource blocks decreases the SE performance loss due to EE optimization when compared with the optimized SE performance. © 2016 IEEE.

  8. CO Spectral Line Energy Distributions in Galactic Sources: Empirical Interpretation of Extragalactic Observations

    Energy Technology Data Exchange (ETDEWEB)

    Indriolo, Nick; Bergin, E. A. [Department of Astronomy, University of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109 (United States); Goicoechea, J. R.; Cernicharo, J. [Grupo de Astrofísica Molecular, Instituto de Ciencia de Materiales de Madrid (CSIC) E-28049 Madrid (Spain); Gerin, M.; Gusdorf, A. [LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, École normale supérieure, F-75005, Paris (France); Lis, D. C. [LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-75014, Paris (France); Schilke, P., E-mail: nindriolo@stsci.edu [I. Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, D-50937 Köln (Germany)

    2017-02-10

    The relative populations in rotational transitions of CO can be useful for inferring gas conditions and excitation mechanisms at work in the interstellar medium. We present CO emission lines from rotational transitions observed with Herschel /HIFI in the star-forming cores Orion S, Orion KL, Sgr B2(M), and W49N. Integrated line fluxes from these observations are combined with those from Herschel /PACS observations of the same sources to construct CO spectral line energy distributions (SLEDs) from 5≤ J{sub u} ≤ 48. These CO SLEDs are compared to those reported in other galaxies, with the intention of empirically determining which mechanisms dominate excitation in such systems. We find that CO SLEDs in Galactic star-forming cores cannot be used to reproduce those observed in other galaxies, although the discrepancies arise primarily as a result of beam filling factors. The much larger regions sampled by the Herschel beams at distances of several megaparsecs contain significant amounts of cooler gas, which dominate the extragalactic CO SLEDs, in contrast to observations of Galactic star-forming regions, which are focused specifically on cores containing primarily hot molecular gas.

  9. Energy Efficiency - Spectral Efficiency Trade-off: A Multiobjective Optimization Approach

    KAUST Repository

    Amin, Osama

    2015-04-23

    In this paper, we consider the resource allocation problem for energy efficiency (EE) - spectral efficiency (SE) trade-off. Unlike traditional research that uses the EE as an objective function and imposes constraints either on the SE or achievable rate, we propound a multiobjective optimization approach that can flexibly switch between the EE and SE functions or change the priority level of each function using a trade-off parameter. Our dynamic approach is more tractable than the conventional approaches and more convenient to realistic communication applications and scenarios. We prove that the multiobjective optimization of the EE and SE is equivalent to a simple problem that maximizes the achievable rate/SE and minimizes the total power consumption. Then we apply the generalized framework of the resource allocation for the EE-SE trade-off to optimally allocate the subcarriers’ power for orthogonal frequency division multiplexing (OFDM) with imperfect channel estimation. Finally, we use numerical results to discuss the choice of the trade-off parameter and study the effect of the estimation error, transmission power budget and channel-to-noise ratio on the multiobjective optimization.

  10. Resource allocation for phantom cellular networks: Energy efficiency vs spectral efficiency

    KAUST Repository

    Abdelhady, Amr M.

    2016-07-26

    Multi-tier heterogeneous networks have become an essential constituent for next generation cellular networks. Mean-while, energy efficiency (EE) has been considered a critical design criterion along with the traditional spectral efficiency (SE) metric. In this context, we study power and spectrum allocation for the recently proposed two-tier network architecture known as phantom cellular networks. The optimization framework includes both EE and SE, where we propose an algorithm that finds the SE and EE resource allocation strategies for phantom cellular networks. Then, we compare the performance of both design strategies versus the number of users, and phantom cells share of the total number of available resource blocks. We aim to investigate the effect of some system parameters to achieve improved SE performance at a non-significant loss in EE performance, or vice versa. It was found that increasing phantom cells share of resource blocks decreases the SE performance loss due to EE optimization when compared with the optimized SE performance. © 2016 IEEE.

  11. Modelling performance of a small array of Wave Energy Converters: Comparison of Spectral and Boussinesq models

    International Nuclear Information System (INIS)

    Greenwood, Charles; Christie, David; Venugopal, Vengatesan; Morrison, James; Vogler, Arne

    2016-01-01

    This paper presents results from numerical simulations of three Oscillating Wave Surge Converters (OWSC) using two different computational models, Boussinesq wave (BW) and Spectral wave (SW) of the commercial software suite MIKE. The simulation of a shallow water wave farm applies alternative methods for implementing a frequency dependent absorption in both the BW and SW models, where energy extraction is based on experimental data from a scaled Oyster device. The effects of including wave diffraction within the SW model is tested by using diffraction smoothing steps and various directional wave conditions. The results of this study reveal important information on the models realms of validity that is heavily dependent on the incident sea state and the removal of diffraction for the SW model. This yields an increase in simulation accuracy for far-field disturbances when diffraction is entirely removed. This highlights specific conditions where the BW and SW model may thrive but also regions where reduced performance is observed. The results presented in this paper have not been validated with real sea site wave device array performance, however, the methodology described would be useful to device developers to arrive at preliminary decisions on array configurations and to minimise negative environmental impacts.

  12. SURVEY DESIGN FOR SPECTRAL ENERGY DISTRIBUTION FITTING: A FISHER MATRIX APPROACH

    International Nuclear Information System (INIS)

    Acquaviva, Viviana; Gawiser, Eric; Bickerton, Steven J.; Grogin, Norman A.; Guo Yicheng; Lee, Seong-Kook

    2012-01-01

    The spectral energy distribution (SED) of a galaxy contains information on the galaxy's physical properties, and multi-wavelength observations are needed in order to measure these properties via SED fitting. In planning these surveys, optimization of the resources is essential. The Fisher Matrix (FM) formalism can be used to quickly determine the best possible experimental setup to achieve the desired constraints on the SED-fitting parameters. However, because it relies on the assumption of a Gaussian likelihood function, it is in general less accurate than other slower techniques that reconstruct the probability distribution function (PDF) from the direct comparison between models and data. We compare the uncertainties on SED-fitting parameters predicted by the FM to the ones obtained using the more thorough PDF-fitting techniques. We use both simulated spectra and real data, and consider a large variety of target galaxies differing in redshift, mass, age, star formation history, dust content, and wavelength coverage. We find that the uncertainties reported by the two methods agree within a factor of two in the vast majority (∼90%) of cases. If the age determination is uncertain, the top-hat prior in age used in PDF fitting to prevent each galaxy from being older than the universe needs to be incorporated in the FM, at least approximately, before the two methods can be properly compared. We conclude that the FM is a useful tool for astronomical survey design.

  13. Energy Efficiency - Spectral Efficiency Trade-off: A Multiobjective Optimization Approach

    KAUST Repository

    Amin, Osama; Bedeer, Ebrahim; Ahmed, Mohamed; Dobre, Octavia

    2015-01-01

    In this paper, we consider the resource allocation problem for energy efficiency (EE) - spectral efficiency (SE) trade-off. Unlike traditional research that uses the EE as an objective function and imposes constraints either on the SE or achievable rate, we propound a multiobjective optimization approach that can flexibly switch between the EE and SE functions or change the priority level of each function using a trade-off parameter. Our dynamic approach is more tractable than the conventional approaches and more convenient to realistic communication applications and scenarios. We prove that the multiobjective optimization of the EE and SE is equivalent to a simple problem that maximizes the achievable rate/SE and minimizes the total power consumption. Then we apply the generalized framework of the resource allocation for the EE-SE trade-off to optimally allocate the subcarriers’ power for orthogonal frequency division multiplexing (OFDM) with imperfect channel estimation. Finally, we use numerical results to discuss the choice of the trade-off parameter and study the effect of the estimation error, transmission power budget and channel-to-noise ratio on the multiobjective optimization.

  14. A novel approach for characterizing broad-band radio spectral energy distributions

    Science.gov (United States)

    Harvey, V. M.; Franzen, T.; Morgan, J.; Seymour, N.

    2018-05-01

    We present a new broad-band radio frequency catalogue across 0.12 GHz ≤ ν ≤ 20 GHz created by combining data from the Murchison Widefield Array Commissioning Survey, the Australia Telescope 20 GHz survey, and the literature. Our catalogue consists of 1285 sources limited by S20 GHz > 40 mJy at 5σ, and contains flux density measurements (or estimates) and uncertainties at 0.074, 0.080, 0.119, 0.150, 0.180, 0.408, 0.843, 1.4, 4.8, 8.6, and 20 GHz. We fit a second-order polynomial in log-log space to the spectral energy distributions of all these sources in order to characterize their broad-band emission. For the 994 sources that are well described by a linear or quadratic model we present a new diagnostic plot arranging sources by the linear and curvature terms. We demonstrate the advantages of such a plot over the traditional radio colour-colour diagram. We also present astrophysical descriptions of the sources found in each segment of this new parameter space and discuss the utility of these plots in the upcoming era of large area, deep, broad-band radio surveys.

  15. Spectral Modeling of Residual Stress and Stored Elastic Strain Energy in Thermal Barrier Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Donegan, Sean; Rolett, Anthony

    2013-12-31

    Solutions to the thermoelastic problem are important for characterizing the response under temperature change of refractory systems. This work extends a spectral fast Fourier transform (FFT) technique to analyze the thermoelastic behavior of thermal barrier coatings (TBCs), with the intent of probing the local origins of failure in TBCs. The thermoelastic FFT (teFFT) approach allows for the characterization of local thermal residual stress and strain fields, which constitute the origins of failure in TBC systems. A technique based on statistical extreme value theory known as peaks-over-threshold (POT) is developed to quantify the extreme values ("hot spots") of stored elastic strain energy (i.e., elastic energy density, or EED). The resolution dependence of the teFFT method is assessed through a sensitivity study of the extreme values in EED. The sensitivity study is performed both for the local (point-by-point) eld distributions as well as the grain scale eld distributions. A convergence behavior to a particular distribution shape is demonstrated for the local elds. The grain scale fields are shown to exhibit a possible convergence to a maximum level of EED. To apply the teFFT method to TBC systems, 3D synthetic microstructures are created to approximate actual TBC microstructures. The morphology of the grains in each constituent layer as well as the texture is controlled. A variety of TBC materials, including industry standard materials and potential future materials, are analyzed using the teFFT. The resulting hot spots are quantified using the POT approach. A correlation between hot spots in EED and interface rumpling between constituent layers is demonstrated, particularly for the interface between the bond coat (BC) and the thermally grown oxide (TGO) layer.

  16. Determination of the electron-hole pair creation energy for semiconductors from the spectral responsivity of photodiodes

    CERN Document Server

    Scholze, F; Kuschnerus, P; Rabus, H; Richter, M; Ulm, G

    2000-01-01

    Ionizing radiation can be detected by the measurement of the charge carriers produced in a detector. The improved semiconductor technology now allows detectors operating near the physical limits of the detector materials to be designed. The mean energy required for producing an electron-hole pair, W, is a material property of the semiconductor. Here, the determination of W from the spectral responsivity of photodiodes is demonstrated. Using spectrally dispersed synchrotron radiation, different types of semiconductor photodiodes have been examined in the UV-, VUV-, and soft X-ray spectral range. Their spectral responsivity was determined with relative uncertainties between 0.4% and 1% using a cryogenic electrical-substitution radiometer as primary detector standard. Results are presented for silicon n-on-p junction photodiodes and for GaAsP/Au Schottky diodes at room temperature. The investigations for silicon covered the complete spectral range from 3 to 1500 eV, yielding a constant value W=(3.66+-0.03) eV fo...

  17. Dual-Energy Computed Tomography Gemstone Spectral Imaging: A Novel Technique to Determine Human Cardiac Calculus Composition.

    Science.gov (United States)

    Cheng, Ching-Li; Chang, Hsiao-Huang; Ko, Shih-Chi; Huang, Pei-Jung; Lin, Shan-Yang

    2016-01-01

    Understanding the chemical composition of any calculus in different human organs is essential for choosing the best treatment strategy for patients. The purpose of this study was to assess the capability of determining the chemical composition of a human cardiac calculus using gemstone spectral imaging (GSI) mode on a single-source dual-energy computed tomography (DECT) in vitro. The cardiac calculus was directly scanned on the Discovery CT750 HD FREEdom Edition using GSI mode, in vitro. A portable fiber-optic Raman spectroscopy was also applied to verify the quantitative accuracy of the DECT measurements. The results of spectral DECT measurements indicate that effective Z values in 3 designated positions located in this calculus were 15.02 to 15.47, which are close to values of 15.74 to 15.86, corresponding to the effective Z values of calcium apatite and hydroxyapatite. The Raman spectral data were also reflected by the predominant Raman peak at 960 cm for hydroxyapatite and the minor peak at 875 cm for calcium apatite. A potential single-source DECT with GSI mode was first used to examine the morphological characteristics and chemical compositions of a giant human cardiac calculus, in vitro. The CT results were consistent with the Raman spectral data, suggesting that spectral CT imaging techniques could be accurately used to diagnose and characterize the compositional materials in the cardiac calculus.

  18. Far-infrared radiation acutely increases nitric oxide production by increasing Ca2+ mobilization and Ca2+/calmodulin-dependent protein kinase II-mediated phosphorylation of endothelial nitric oxide synthase at serine 1179

    International Nuclear Information System (INIS)

    Park, Jung-Hyun; Lee, Sangmi; Cho, Du-Hyong; Park, Young Mi; Kang, Duk-Hee; Jo, Inho

    2013-01-01

    Highlights: •Far-infrared (FIR) radiation increases eNOS-Ser 1179 phosphorylation and NO production in BAEC. •CaMKII and PKA mediate FIR-stimulated increases in eNOS-Ser 1179 phosphorylation. •FIR increases intracellular Ca 2+ levels. •Thermo-sensitive TRPV Ca 2+ channels are unlikely to be involved in the FIR-mediated eNOS-Ser 1179 phosphorylation pathway. -- Abstract: Repeated thermal therapy manifested by far-infrared (FIR) radiation improves vascular function in both patients and mouse model with coronary heart disease, but its underlying mechanism is not fully understood. Using FIR as a thermal therapy agent, we investigate the molecular mechanism of its effect on endothelial nitric oxide synthase (eNOS) activity and NO production. FIR increased the phosphorylation of eNOS at serine 1179 (eNOS-Ser 1179 ) in a time-dependent manner (up to 40 min of FIR radiation) in bovine aortic endothelial cells (BAEC) without alterations in eNOS expression. This increase was accompanied by increases in NO production and intracellular Ca 2+ levels. Treatment with KN-93, a selective inhibitor of Ca 2+ /calmodulin-dependent protein kinase II (CaMKII) and H-89, a protein kinase A inhibitor, inhibited FIR radiation-stimulated eNOS-Ser 1179 phosphorylation. FIR radiation itself also increased the temperature of culture medium. As transient receptors potential vanilloid (TRPV) ion channels are known to be temperature-sensitive calcium channels, we explore whether TRPV channels mediate these observed effects. Reverse transcription-PCR assay revealed two TRPV isoforms in BAEC, TRPV2 and TRPV4. Although ruthenium red, a pan-TRPV inhibitor, completely reversed the observed effect of FIR radiation, a partial attenuation (∼20%) was found in cells treated with Tranilast, TRPV2 inhibitor. However, ectopic expression of siRNA of TRPV2 showed no significant alteration in FIR radiation-stimulated eNOS-Ser 1179 phosphorylation. This study suggests that FIR radiation increases NO

  19. Far-infrared radiation acutely increases nitric oxide production by increasing Ca{sup 2+} mobilization and Ca{sup 2+}/calmodulin-dependent protein kinase II-mediated phosphorylation of endothelial nitric oxide synthase at serine 1179

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jung-Hyun; Lee, Sangmi [Department of Molecular Medicine and Ewha Medical Research Institute, Ewha Womans University Medical School, Seoul 158-710 (Korea, Republic of); Cho, Du-Hyong [Department of Neuroscience, School of Medicine, Konkuk University, Seoul 143-701 (Korea, Republic of); Park, Young Mi [Department of Molecular Medicine and Ewha Medical Research Institute, Ewha Womans University Medical School, Seoul 158-710 (Korea, Republic of); Kang, Duk-Hee [Division of Nephrology, Department of Internal Medicine, Ewha Womans University Medical School, Seoul 158-710 (Korea, Republic of); Jo, Inho, E-mail: inhojo@ewha.ac.kr [Department of Molecular Medicine and Ewha Medical Research Institute, Ewha Womans University Medical School, Seoul 158-710 (Korea, Republic of)

    2013-07-12

    Highlights: •Far-infrared (FIR) radiation increases eNOS-Ser{sup 1179} phosphorylation and NO production in BAEC. •CaMKII and PKA mediate FIR-stimulated increases in eNOS-Ser{sup 1179} phosphorylation. •FIR increases intracellular Ca{sup 2+} levels. •Thermo-sensitive TRPV Ca{sup 2+} channels are unlikely to be involved in the FIR-mediated eNOS-Ser{sup 1179} phosphorylation pathway. -- Abstract: Repeated thermal therapy manifested by far-infrared (FIR) radiation improves vascular function in both patients and mouse model with coronary heart disease, but its underlying mechanism is not fully understood. Using FIR as a thermal therapy agent, we investigate the molecular mechanism of its effect on endothelial nitric oxide synthase (eNOS) activity and NO production. FIR increased the phosphorylation of eNOS at serine 1179 (eNOS-Ser{sup 1179}) in a time-dependent manner (up to 40 min of FIR radiation) in bovine aortic endothelial cells (BAEC) without alterations in eNOS expression. This increase was accompanied by increases in NO production and intracellular Ca{sup 2+} levels. Treatment with KN-93, a selective inhibitor of Ca{sup 2+}/calmodulin-dependent protein kinase II (CaMKII) and H-89, a protein kinase A inhibitor, inhibited FIR radiation-stimulated eNOS-Ser{sup 1179} phosphorylation. FIR radiation itself also increased the temperature of culture medium. As transient receptors potential vanilloid (TRPV) ion channels are known to be temperature-sensitive calcium channels, we explore whether TRPV channels mediate these observed effects. Reverse transcription-PCR assay revealed two TRPV isoforms in BAEC, TRPV2 and TRPV4. Although ruthenium red, a pan-TRPV inhibitor, completely reversed the observed effect of FIR radiation, a partial attenuation (∼20%) was found in cells treated with Tranilast, TRPV2 inhibitor. However, ectopic expression of siRNA of TRPV2 showed no significant alteration in FIR radiation-stimulated eNOS-Ser{sup 1179} phosphorylation. This

  20. Optically Pumped Far Infrared Molecular Lasers.

    Science.gov (United States)

    1980-04-01

    and 4 were reported by Fetterman , et al. and Gullberg, et al.3 An additional FIR transition (i.e., G:sR(5,4) has been reported,5 but is not shown in...attempt has been made to frequency stabilize the experiment. Recently, Fetterman , et al. 11 performed "real-ti adctral analysis for FIR laser pulses...wave device known 4 as a Reflective Array Compressor (RAC) was developed for just this sort of problem in the radar community. Recently, Fetterman , et al

  1. Revisiting the Correlations of Peak Luminosity with Spectral Lag and Peak Energy of the Observed Gamma-ray Bursts

    Directory of Open Access Journals (Sweden)

    Yun-A Jo

    2016-12-01

    Full Text Available An analysis of light curves and spectra of observed gamma-ray bursts in gamma-ray ranges is frequently demanded because the prompt emission contains immediate details regarding the central engine of gamma-ray bursts (GRBs. We have revisited the relationship between the collimation-corrected peak luminosity and the spectral lag, investigating the lag-luminosity relationships in great detail by focusing on spectral lags resulting from all possible combinations of channels. Firstly, we compiled the opening angle data and demonstrated that the distribution of opening angles of 205 long GRBs is represented by a double Gaussian function having maxima at ~ 0.1 and ~ 0.3 radians. We confirmed that the peak luminosity and the spectral lag are anti-correlated, both in the observer frame and in the source frame. We found that, in agreement with our previous conclusion, the correlation coefficient improves significantly in the source frame. It should be noted that spectral lags involving channel 2 (25-50 keV yield high correlation coefficients, where Swift/Burst Alert Telescope (BAT has four energy channels (channel 1: 15-25 keV, channel 2: 25-50 keV, channel 3: 50-100 keV, channel 4: 100-200 keV. We also found that peak luminosity is positively correlated with peak energy.

  2. Development of Neutron Energy Spectral Signatures for Passive Monitoring of Spent Nuclear Fuels in Dry Cask Storage

    Science.gov (United States)

    Harkness, Ira; Zhu, Ting; Liang, Yinong; Rauch, Eric; Enqvist, Andreas; Jordan, Kelly A.

    2018-01-01

    Demand for spent nuclear fuel dry casks as an interim storage solution has increased globally and the IAEA has expressed a need for robust safeguards and verification technologies for ensuring the continuity of knowledge and the integrity of radioactive materials inside spent fuel casks. Existing research has been focusing on "fingerprinting" casks based on count rate statistics to represent radiation emission signatures. The current research aims to expand to include neutron energy spectral information as part of the fuel characteristics. First, spent fuel composition data are taken from the Next Generation Safeguards Initiative Spent Fuel Libraries, representative for Westinghouse 17ˣ17 PWR assemblies. The ORIGEN-S code then calculates the spontaneous fission and (α,n) emissions for individual fuel rods, followed by detailed MCNP simulations of neutrons transported through the fuel assemblies. A comprehensive database of neutron energy spectral profiles is to be constructed, with different enrichment, burn-up, and cooling time conditions. The end goal is to utilize the computational spent fuel library, predictive algorithm, and a pressurized 4He scintillator to verify the spent fuel assemblies inside a cask. This work identifies neutron spectral signatures that correlate with the cooling time of spent fuel. Both the total and relative contributions from spontaneous fission and (α,n) change noticeably with respect to cooling time, due to the relatively short half-life (18 years) of the major neutron source 244Cm. Identification of this and other neutron spectral signatures allows the characterization of spent nuclear fuels in dry cask storage.

  3. Front Surface Tandem Filters using Sapphire (Al2O3) Substrates for Spectral Control in thermophotovoltaic Energy Conversion Systems

    International Nuclear Information System (INIS)

    T Rahmlow, Jr.; J Lazo-Wasem; E Gratrix; P Fourspring; D DePoy

    2005-01-01

    Front surface filters provide an effective means of improving thermophotovoltaic (TPV) system efficiency through spectral control of incident radiant energy. A front surface filter reflects the below band gap photons that can not be converted by the TPV cell back towards the high temperature radiator and allows convertible above band gap photons to pass through the filter into the TPV cell for conversion to electricity. The best spectral control efficiency to date has been demonstrated by front surface, tandem filters that combine an interference filter and an InPAs layer (plasma filter) in series. The InPAs material is a highly doped, epitaxially grown layer on an InP substrate. These tandem filter designs have been fabricated with energy and angle weighted spectral efficiencies of 76% for TPV cells with a 2.08(micro)m (0.6eV) band gap [1]. An alternative to the InPAs layer on an InP substrate is an Al 2 O 3 (sapphire) substrate. The use of Al 2 O 3 may increase transmission of above band gap photons, increase the mechanical strength of the tandem filter, and lower the cost of the tandem filter, all at the expense of lower spectral efficiency. This study presents design and fabrication results for front surface tandem filters that use an Al 2 O 3 substrate for 2.08(micro)m band gap TPV cells

  4. Global Infrared–Radio Spectral Energy Distributions of Galactic Massive Star-Forming Regions

    Science.gov (United States)

    Povich, Matthew Samuel; Binder, Breanna Arlene

    2018-01-01

    We present a multiwavelength study of 30 Galactic massive star-forming regions. We fit multicomponent dust, blackbody, and power-law continuum models to 3.6 µm through 10 mm spectral energy distributions obtained from Spitzer, MSX, IRAS, Herschel, and Planck archival survey data. Averaged across our sample, ~20% of Lyman continuum photons emitted by massive stars are absorbed by dust before contributing to the ionization of H II regions, while ~50% of the stellar bolometric luminosity is absorbed and reprocessed by dust in the H II regions and surrounding photodissociation regions. The most luminous, infrared-bright regions that fully sample the upper stellar initial mass function (ionizing photon rates NC ≥ 1050 s–1 and total infrared luminosity LTIR ≥ 106.8 L⊙) have higher percentages of absorbed Lyman continuum photons (~40%) and dust-reprocessed starlight (~80%). The monochromatic 70-µm luminosity L70 is linearly correlated with LTIR, and on average L70/LTIR = 50%, in good agreement with extragalactic studies. Calibrated against the known massive stellar content in our sampled H II regions, we find that star formation rates based on L70 are in reasonably good agreement with extragalactic calibrations, when corrected for the smaller physical sizes of the Galactic regions. We caution that absorption of Lyman continuum photons prior to contributing to the observed ionizing photon rate may reduce the attenuation-corrected Hα emission, systematically biasing extragalactic calibrations toward lower star formation rates when applied to spatially-resolved studies of obscured star formation.This work was supported by the National Science Foundation under award CAREER-1454333.

  5. Spectral energy distribution variations of nearby Seyfert galaxies during AGN watch monitoring programs

    Science.gov (United States)

    Kilerci Eser, Ece; Vestergaard, M.

    2018-02-01

    We present and analyse quasi-simultaneous multi-epoch spectral energy distributions (SEDs) of seven reverberation-mapped active galactic nuclei (AGNs) for which accurate black hole mass measurements and suitable archival data are available from the `AGN Watch' monitoring programs. We explore the potential of optical-UV and X-ray data, obtained within 2 d, to provide more accurate SED-based measurements of individual AGN and quantify the impact of source variability on key measurements typically used to characterize the black hole accretion process plus on bolometric correction factors at 5100 Å, 1350 Å and for the 2-10 keV X-ray band, respectively. The largest SED changes occur on long time-scales (≳1 year). For our small sample, the 1μm to 10 keV integrated accretion luminosity typically changes by 10 per cent on short time-scales (over 20 d), by ˜30 per cent over a year, but can change by 100 per cent or more for individual AGN. The extreme ultraviolet (EUV) gap is the most uncertain part of the intrinsic SED, introducing a ˜25 per cent uncertainty in the accretion-induced luminosity, relative to the model independent interpolation method that we adopt. That aside, our analysis shows that the uncertainty in the accretion-induced luminosity, the Eddington luminosity ratio and the bolometric correction factors can be reduced (by a factor of two or more) by use of the SEDs built from data obtained within 20 d. However, \\dot{M} and η are mostly limited by the unknown EUV emission and the unknown details of the central engine and our aspect angle.

  6. Spectral energy distribution analysis of class I and class II FU Orionis stars

    Energy Technology Data Exchange (ETDEWEB)

    Gramajo, Luciana V.; Gómez, Mercedes [Observatorio Astronómico, Universidad Nacional de Córdoba, Argentina, Laprida 854, 5000 Córdoba (Argentina); Rodón, Javier A., E-mail: luciana@oac.uncor.edu, E-mail: mercedes@oac.uncor.edu, E-mail: jrodon@eso.org [European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago 19 (Chile)

    2014-06-01

    FU Orionis stars (FUors) are eruptive pre-main sequence objects thought to represent quasi-periodic or recurring stages of enhanced accretion during the low-mass star-forming process. We characterize the sample of known and candidate FUors in a homogeneous and consistent way, deriving stellar and circumstellar parameters for each object. We emphasize the analysis in those parameters that are supposed to vary during the FUor stage. We modeled the spectral energy distributions of 24 of the 26 currently known FUors, using the radiative transfer code of Whitney et al. We compare our models with those obtained by Robitaille et al. for Taurus class II and I sources in quiescence periods by calculating the cumulative distribution of the different parameters. FUors have more massive disks: we find that ∼80% of the disks in FUors are more massive than any Taurus class II and I sources in the sample. Median values for the disk mass accretion rates are ∼10{sup –7} M {sub ☉} yr{sup –1} versus ∼10{sup –5} M {sub ☉} yr{sup –1} for standard young stellar objects (YSOs) and FUors, respectively. While the distributions of envelope mass accretion rates for class I FUors and standard class I objects are similar, FUors, on average, have higher envelope mass accretion rates than standard class II and class I sources. Most FUors (∼70%) have envelope mass accretion rates above 10{sup –7} M {sub ☉} yr{sup –1}. In contrast, 60% of the classical YSO sample has an accretion rate below this value. Our results support the current scenario in which changes experimented by the circumstellar disk explain the observed properties of these stars. However, the increase in the disk mass accretion rate is smaller than theoretically predicted, although in good agreement with previous determinations.

  7. HerMES: Spectral energy distributions of submillimeter galaxies at z > 4

    International Nuclear Information System (INIS)

    Huang, J.-S.; Rigopoulou, D.; Magdis, G.; Rowan-Robinson, M.; Clements, D. L.; Dai, Y.; Fazio, G. G.; Bock, J. J.; Burgarella, D.; Chapman, S.; Cooray, A.; Farrah, D.; Glenn, J.; Oliver, S.; Smith, A. J.; Wang, L.; Page, M.; Symeonidis, M.; Riechers, D.; Roseboom, I.

    2014-01-01

    We present a study of the infrared properties for a sample of seven spectroscopically confirmed submillimeter galaxies (SMGs) at z > 4.0. By combining ground-based near-infrared, Spitzer IRAC and MIPS, Herschel SPIRE, and ground-based submillimeter/millimeter photometry, we construct their spectral energy distributions (SEDs) and a composite model to fit the SEDs. The model includes a stellar emission component at λ rest < 3.5 μm, a hot dust component peaking at λ rest ∼ 5 μm, and cold dust component which becomes significant for λ rest > 50 μm. Six objects in the sample are detected at 250 and 350 μm. The dust temperatures for the sources in this sample are in the range of 40-80 K, and their L FIR ∼ 10 13 L ☉ qualifies them as hyper-luminous infrared galaxies. The mean FIR-radio index for this sample is around (q) = 2.2 indicating no radio excess in their radio emission. Most sources in the sample have 24 μm detections corresponding to a rest-frame 4.5 μm luminosity of Log 10 (L 4.5 /L ☉ ) = 11 ∼ 11.5. Their L 4.5 /L FIR ratios are very similar to those of starburst-dominated SMGs at z ∼ 2. The L CO – L FIR relation for this sample is consistent with that determined for local ULIRGs and SMGs at z ∼ 2. We conclude that SMGs at z > 4 are hotter and more luminous in the FIR but otherwise very similar to those at z ∼ 2. None of these sources show any sign of the strong QSO phase being triggered.

  8. Semiconductor detectors in current energy dispersive X-ray spectral analysis

    Energy Technology Data Exchange (ETDEWEB)

    Betin, J; Zhabin, E; Krampit, I; Smirnov, V

    1980-04-01

    A review is presented of the properties of semiconductor detectors and of the possibilities stemming therefrom of using the detectors in X-ray spectral analysis in industries, in logging, in ecology and environmental control, in medicine, etc.

  9. Spectral-Efficiency - Illumination Pareto Front for Energy Harvesting Enabled VLC System

    KAUST Repository

    Abdelhady, Amr Mohamed Abdelaziz; Amin, Osama; Chaaban, Anas; Alouini, Mohamed-Slim

    2017-01-01

    . The adopted optical system provides users with illumination and data communication services. The outdoor optical design objective is to maximize the illumination, while the communication design objective is to maximize the spectral efficiency (SE). The design

  10. Spectral and energy efficiency analysis of uplink heterogeneous networks with small-cells on edge

    KAUST Repository

    Shakir, Muhammad Zeeshan; Tabassum, Hina; Qaraqe, Khalid A.; Serpedin, Erchin; Alouini, Mohamed-Slim

    2014-01-01

    by considering fast power control where the mobile users transmit with adaptive power to compensate the path loss, shadowing and fading. In particular, we develop a moment generating function (MGF) based approach to derive analytical bounds on the area spectral

  11. Techniques for Handling and Removal of Spectral Channels in Fourier Transform Synchrotron-Based Spectra

    International Nuclear Information System (INIS)

    Ibrahim, Amr; Predoi-Cross, Adriana; Teillet, Philippe M.

    2010-01-01

    Channel spectra are a big problem for those attempting to use synchrotron-based Fourier transform spectra for spectral lineshape studies. Due to the layout of the optical system at the CLS far-infrared beamline, the synchrotron beam undergoes unavoidable multiple reflections on the steering mirrors, beam splitter, several sets of windows, and filters. We present a method for eliminating channel spectra and compare the results of our technique with other methods available in the literature.

  12. Investigating the optical modes of InxGa1xN alloy and In0.5Ga0.5N/GaN MQW in far-infrared reflectivity spectra

    International Nuclear Information System (INIS)

    Mirjalili, G.; Amraei, R.

    2006-01-01

    Optical properties of In x Ga 1 x N alloy and In 0 .5Ga 0 .5N/GaN multi quantum wells have been investigated in the region of far infrared. Far-IR reflectivity spectra of In 0 .5Ga 0 .5N/GaN multi quantum wells on GaAs substrate have been obtained by oblique incidence p- and s- polarization light using effective medium approximation. The spectra and the dielectric functions response give a good information about the phonon and plasmon contribution in doped MQW as well as the mole fraction of compounds in the alloys. The changes in position of optical modes are good tools for measurement of the amount of free carrier and the amount of mole fraction in the samples. During study of In x Ga 1 x N reflectivity spectra, two distinct reststrahl bands with frequency near those of pure InN and GaN were observed over entire composition range. Each band shifts to lower frequencies and decreases in amplitude as the concentration of corresponding compound in alloy decreased. Analysis of dielectric function gives the TO-like and LO-like mode frequencies. The changes in LO mode frequencies, due to coupling of phonon-plasmon, have been observed

  13. Enhancing inhibition-induced plasticity in tinnitus--spectral energy contrasts in tailor-made notched music matter.

    Directory of Open Access Journals (Sweden)

    Alwina Stein

    Full Text Available Chronic tinnitus seems to be caused by reduced inhibition among frequency selective neurons in the auditory cortex. One possibility to reduce tinnitus perception is to induce inhibition onto over-activated neurons representing the tinnitus frequency via tailor-made notched music (TMNM. Since lateral inhibition is modifiable by spectral energy contrasts, the question arises if the effects of inhibition-induced plasticity can be enhanced by introducing increased spectral energy contrasts (ISEC in TMNM. Eighteen participants suffering from chronic tonal tinnitus, pseudo randomly assigned to either a classical TMNM or an ISEC-TMNM group, listened to notched music for three hours on three consecutive days. The music was filtered for both groups by introducing a notch filter centered at the individual tinnitus frequency. For the ISEC-TMNM group a frequency bandwidth of 3/8 octaves on each side of the notch was amplified, additionally, by about 20 dB. Before and after each music exposure, participants rated their subjectively perceived tinnitus loudness on a visual analog scale. During the magnetoencephalographic recordings, participants were stimulated with either a reference tone of 500 Hz or a test tone with a carrier frequency representing the individual tinnitus pitch. Perceived tinnitus loudness was significantly reduced after TMNM exposure, though TMNM type did not influence the loudness ratings. Tinnitus related neural activity in the N1m time window and in the so called tinnitus network comprising temporal, parietal and frontal regions was reduced after TMNM exposure. The ISEC-TMNM group revealed even enhanced inhibition-induced plasticity in a temporal and a frontal cortical area. Overall, inhibition of tinnitus related neural activity could be strengthened in people affected with tinnitus by increasing spectral energy contrast in TMNM, confirming the concepts of inhibition-induced plasticity via TMNM and spectral energy contrasts.

  14. 40 CFR Table E-2 to Subpart E of... - Spectral Energy Distribution and Permitted Tolerance for Conducting Radiative Tests

    Science.gov (United States)

    2010-07-01

    ... Permitted Tolerance for Conducting Radiative Tests E Table E-2 to Subpart E of Part 53 Protection of... Reference Methods and Class I and Class II Equivalent Methods for PM2.5 or PM10â2.5 Pt. 53, Subpt. E, Table E-2 Table E-2 to Subpart E of Part 53—Spectral Energy Distribution and Permitted Tolerance for...

  15. SDP_mharwit_1: Demonstration of HIFI Linear Polarization Analysis of Spectral Features

    Science.gov (United States)

    Harwit, M.

    2010-03-01

    We propose to observe the polarization of the 621 GHz water vapor maser in VY Canis Majoris to demonstrate the capability of HIFI to make polarization observations of Far-Infrared/Submillimeter spectral lines. The proposed Demonstration Phase would: - Show that HIFI is capable of interesting linear polarization measurements of spectral lines; - Test out the highest spectral resolving power to sort out closely spaced Doppler components; - Determine whether the relative intensities predicted by Neufeld and Melnick are correct; - Record the degree and direction of linear polarization for the closely-Doppler shifted peaks.

  16. IDEN2-A program for visual identification of spectral lines and energy levels in optical spectra of atoms and simple molecules

    Science.gov (United States)

    Azarov, V. I.; Kramida, A.; Vokhmentsev, M. Ya.

    2018-04-01

    The article describes a Java program that can be used in a user-friendly way to visually identify spectral lines observed in complex spectra with theoretically predicted transitions between atomic or molecular energy levels. The program arranges various information about spectral lines and energy levels in such a way that line identification and determination of positions of experimentally observed energy levels become much easier tasks that can be solved fast and efficiently.

  17. Time evolution of the spectral break in the high-energy extra component of GRB 090926A

    Science.gov (United States)

    Yassine, M.; Piron, F.; Mochkovitch, R.; Daigne, F.

    2017-10-01

    Aims: The prompt light curve of the long GRB 090926A reveals a short pulse 10 s after the beginning of the burst emission, which has been observed by the Fermi observatory from the keV to the GeV energy domain. During this bright spike, the high-energy emission from GRB 090926A underwent a sudden hardening above 10 MeV in the form of an additional power-law component exhibiting a spectral attenuation at a few hundreds of MeV. This high-energy break has been previously interpreted in terms of gamma-ray opacity to pair creation and has been used to estimate the bulk Lorentz factor of the outflow. In this article, we report on a new time-resolved analysis of the GRB 090926A broadband spectrum during its prompt phase and on its interpretation in the framework of prompt emission models. Methods: We characterized the emission from GRB 090926A at the highest energies with Pass 8 data from the Fermi Large Area Telescope (LAT), which offer a greater sensitivity than any data set used in previous studies of this burst, particularly in the 30-100 MeV energy band. Then, we combined the LAT data with the Fermi Gamma-ray Burst Monitor (GBM) in joint spectral fits to characterize the time evolution of the broadband spectrum from keV to GeV energies. We paid careful attention to the systematic effects that arise from the uncertainties on the LAT response. Finally, we performed a temporal analysis of the light curves and we computed the variability timescales from keV to GeV energies during and after the bright spike. Results: Our analysis confirms and better constrains the spectral break, which has been previously reported during the bright spike. Furthermore, it reveals that the spectral attenuation persists at later times with an increase of the break characteristic energy up to the GeV domain until the end of the prompt phase. We discuss these results in terms of keV-MeV synchroton radiation of electrons accelerated during the dissipation of the jet energy and inverse Compton

  18. The troposphere-to-stratosphere transition in kinetic energy spectra and nonlinear spectral fluxes as seen in ECMWF analyses

    Science.gov (United States)

    Burgess, A. B. H.; Erler, A. R.; Shepherd, T. G.

    2012-04-01

    We present spectra, nonlinear interaction terms, and fluxes computed for horizontal wind fields from high-resolution meteorological analyses made available by ECMWF for the International Polar Year. Total kinetic energy spectra clearly show two spectral regimes: a steep spectrum at large scales and a shallow spectrum in the mesoscale. The spectral shallowing appears at ~200 hPa, and is due to decreasing rotational power with height, which results in the shallower divergent spectrum dominating in the mesoscale. The spectra we find are steeper than those observed in aircraft data and GCM simulations. Though the analyses resolve total spherical harmonic wavenumbers up to n = 721, effects of dissipation on the fluxes and spectra are visible starting at about n = 200. We find a weak forward energy cascade and a downscale enstrophy cascade in the mesoscale. Eddy-eddy nonlinear kinetic energy transfers reach maximum amplitudes at the tropopause, and decrease with height thereafter; zonal mean-eddy transfers dominate in the stratosphere. In addition, zonal anisotropy reaches a minimum at the tropopause. Combined with strong eddy-eddy interactions, this suggests flow in the tropopause region is very active and bears the greatest resemblance to isotropic turbulence. We find constant enstrophy flux over a broad range of wavenumbers around the tropopause and in the upper stratosphere. A relatively constant spectral enstrophy flux at the tropopause suggests a turbulent inertial range, and that the enstrophy flux is resolved. A main result of our work is its implications for explaining the shallow mesoscale spectrum observed in aircraft wind measurements, GCM studies, and now meteorological analyses. The strong divergent component in the shallow mesoscale spectrum indicates unbalanced flow, and nonlinear transfers decreasing quickly with height are characteristic of waves, not turbulence. Together with the downscale flux of energ y through the shallow spectral range, these

  19. Metal artefact reduction in gemstone spectral imaging dual-energy CT with and without metal artefact reduction software

    International Nuclear Information System (INIS)

    Lee, Young Han; Song, Ho-Taek; Kim, Sungjun; Suh, Jin-Suck; Park, Kwan Kyu

    2012-01-01

    To assess the usefulness of gemstone spectral imaging (GSI) dual-energy CT (DECT) with/without metal artefact reduction software (MARs). The DECTs were performed using fast kV-switching GSI between 80 and 140 kV. The CT data were retro-reconstructed with/without MARs, by different displayed fields-of-view (DFOV), and with synthesised monochromatic energy in the range 40-140 keV. A phantom study of size and CT numbers was performed in a titanium plate and a stainless steel plate. A clinical study was performed in 26 patients with metallic hardware. All images were retrospectively reviewed in terms of the visualisation of periprosthetic regions and the severity of beam-hardening artefacts by using a five-point scale. The GSI-MARs reconstruction can markedly reduce the metal-related artefacts, and the image quality was affected by the prosthesis composition and DFOV. The spectral CT numbers of the prosthesis and periprosthetic regions showed different patterns on stainless steel and titanium plates. Dual-energy CT with GSI-MARs can reduce metal-related artefacts and improve the delineation of the prosthesis and periprosthetic region. We should be cautious when using GSI-MARs because the image quality was affected by the prosthesis composition, energy (in keV) and DFOV. The metallic composition and size should be considered in metallic imaging with GSI-MARs reconstruction. circle Metal-related artefacts can be troublesome on musculoskeletal computed tomography (CT). circle Gemstone spectral imaging (GSI) with dual-energy CT (DECT) offers a novel solution circle GSI and metallic artefact reduction software (GSI-MAR) can markedly reduce these artefacts. circle However image quality is influenced by the prosthesis composition and other parameters. circle We should be aware about potential overcorrection when using GSI-MARs. (orig.)

  20. Semiconductor detectors in current energy dispersive X-ray spectral analysis

    International Nuclear Information System (INIS)

    Betin, J.; Zhabin, E.; Krampit, I.; Smirnov, V.

    1980-01-01

    A review is presented of the properties of semiconductor detectors and of the possibilities stemming therefrom of using the detectors in X-ray spectral analysis in industries, in logging, in ecology and environmental control, in medicine, etc. (M.S.)