scholarly journals Emission spectra in the thermal infrared region

1981 ◽  
Author(s):  
Graham R. Hunt
Keyword(s):  
Emission Spectra ◽  
Thermal Infrared ◽  
Infrared Region

Luminescent Properties and Thermometry of CaWO4:Nd3+ in Near Infrared Region

2017 ◽  
Vol 893 ◽  
pp. 156-160
Author(s):  
Rong Xue Wang ◽  
Xiao Bing Luo
Keyword(s):  
Near Infrared ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Infrared Region ◽  
Excitation Spectra ◽  
Efficient Energy Transfer ◽  
Fluorescent Intensity ◽  
Sensor Device ◽  
The Matrix ◽  
Increasing Temperature

CaWO4: xNd3+ (x = 0.005, 0.008, 0.01, 0.015, 0.02, 0.025 0.03) powders have been synthesized by high-temperature solid state reaction. The results of the XRD indicate that Nd3+ ions have entered into the crystal lattice in all compounds successfully. The reflectance spectra show that the matrix has strong absorption. The emission spectra, excitation spectra and different lifetimes between CaWO4 and CaWO4: 0.5% Nd3+ indicate that efficient energy transfer occurs from WO42- cluster to Nd3+ ions. On the basis of the above work, the dependence of fluorescent spectra on temperature was studied. It turned out that, not only the excitation spectra appeared red shift with increasing temperature, but also the dependence of the near infrared fluorescent intensity on temperature is fitting with a linear function. It might be served as a promising phosphor for temperature sensor device.

Biomass burning pollution products C2H6, C2H2, HCOOH, and PAN in the Southern hemisphere UTLS region observed by the GLORIA instrument during the SouthTRAC HALO aircraft campaign Sep-Nov 2019

2020 ◽  
Author(s):  
Felix Friedl-Vallon ◽  
Jörn Ungermann ◽  
Sören Johansson ◽  
Gerald Wetzel ◽  
Markus Geldenhuys ◽  
...  
Keyword(s):  
Long Range ◽  
Biomass Burning ◽  
Cross Sections ◽  
Trajectory Analysis ◽  
Emission Spectra ◽  
Infrared Region ◽  
Tierra Del Fuego ◽  
Secondary Products ◽  
Research Aircraft ◽  
Two Phases

<p>The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an imaging Fourier transform spectrometer (iFTS) using a 2-dimensional detector array to record emission spectra in the mid-infrared region with high spatial resolution. GLORIA has been operated on the High Altitude and Long Range Research Aircraft (HALO) during the SouthTRAC campaign in September-November 2019. The campaign with base in Rio Grande (Tierra del Fuego) consisted of two observational periods, mainly in September and November 2019. Apart from many local flights, between the two phases HALO returned to Germany which allowed us to acquire long-range hemispheric cross-sections.</p><p>Two dimensional distributions of pollution species like C<sub>2</sub>H<sub>6</sub>, C<sub>2</sub>H<sub>2</sub>, HCOOH, and PAN, which are produced as primary and secondary products from biomass burning sources have been derived from the GLORIA observations. We will show that during the hemispheric cross sections as well as during some of the local flights, GLORIA observed pollution plumes with extensions of many kilometres in altitude and hundreds of kilometres horizontally with strongly enhanced concentrations of these species.</p><p>Trajectory analysis as well as comparisons to Microwave Limb Sounder (MLS) satellite observations show that the origin of plumes are mainly fires in South America and Africa, but also first signs of the Australian bush fires have been detected in the UTLS as early as November 2019.</p>

GLORIA observations of pollution tracers C2H6, C2H2, HCOOH, and PAN in the North Atlantic UTLS region

2020 ◽  
Author(s):  
Gerald Wetzel ◽  
Felix Friedl-Vallon ◽  
Norbert Glatthor ◽  
Jens-Uwe Grooß ◽  
Thomas Gulde ◽  
...  
Keyword(s):  
High Altitude ◽  
North Atlantic ◽  
Atmospheric Chemistry ◽  
Emission Spectra ◽  
Infrared Region ◽  
Reanalysis Data ◽  
Lagrangian Model ◽  
Back Trajectories ◽  
Source Regions ◽  
Research Aircraft

<p>The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an imaging Fourier transform spectrometer (iFTS) using a 2-dimensional detector array to record emission spectra in the mid-infrared region with high spatial resolution. GLORIA is operated on high altitude research aircraft, mainly in the limb observational geometry to measure vertical profiles of temperature and atmospheric trace species with high vertical resolution.</p><p>In autumn 2017, the Wave-driven ISentropic Exchange (WISE) aircraft campaign took place from Shannon (Ireland). Sixteen flights with the High Altitude and Long Range Research Aircraft (HALO) were performed between 31 August and 21 October 2017 over the eastern North Atlantic region.</p><p>GLORIA observations were analysed with regard to pollutant species like C<sub>2</sub>H<sub>6</sub>, C<sub>2</sub>H<sub>2</sub>, HCOOH, and PAN, which are produced at distinct source regions near the ground and transported to remote regions due to their atmospheric lifetime of several weeks. Enhanced volume mixing ratios of these molecules were detected along some parts of the flight track in the upper troposphere and lowermost stratosphere (UTLS).</p><p>Measured profiles of these species are compared to simulations from the ECHAM/MESSy Atmospheric Chemistry (EMAC) model and reanalysis data from the Copernicus Atmosphere Monitoring Service (CAMS). Furthermore, emission tracers and back-trajectories from the Chemical Lagrangian Model of the Stratosphere (CLaMS) are used to analyse the source regions of these pollution events.</p>

scholarly journals Dust Identification over Arid and Semiarid Regions of Asia Using AIRS Thermal Infrared Channels

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Hui Xu ◽  
Tianhai Cheng ◽  
Donghai Xie ◽  
Jiaguo Li ◽  
Yu Wu ◽  
...  
Keyword(s):  
Northern China ◽  
Thermal Infrared ◽  
Infrared Region ◽  
Discrete Ordinates ◽  
Orthogonal Polarization ◽  
Identification Algorithm ◽  
Semiarid Regions ◽  
Infrared Signature ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Arid And Semiarid

Asia dust generated in northern China exerts significant influences on regional air quality, weather, and climate. In this study, a dust identification algorithm over arid and semiarid regions of Asia was proposed based on the thermal observations of atmospheric infrared sounder (AIRS). Firstly, a combination of the line-by-line (LBL) and discrete ordinates radiative transfer (DISORT) model was utilized to investigate the thermal infrared signatures of dust and cloud in 800–1250 cm−1region. Secondly, six channels in the thermal infrared region were selected from AIRS to monitor dust from space, and a further sensitivity analysis for dust and cloud under different conditions was also performed. Then, the description of the detailed identification method was provided based on distinct thermal infrared signature of dust. At last, several dust events that observed in northern China between the period of 2008 and 2012 were analyzed, and the usefulness of monitoring the outbreaks of Asian dust was emphasized through the comparison with moderate resolution imaging spectroradiometer (MODIS) visible observations and cloud aerosol lidar with orthogonal polarization (CALIOP) data in this study.

Imaging and Spatially Resolved Spectroscopy of AFGL 2688 in the Thermal Infrared Region

2002 ◽  
Vol 572 (1) ◽  
pp. 276-287 ◽  
Author(s):  
Miwa Goto ◽  
Naoto Kobayashi ◽  
Hiroshi Terada ◽  
A. T. Tokunaga
Keyword(s):  
Thermal Infrared ◽  
Infrared Region ◽  
Spatially Resolved ◽  
Spatially Resolved Spectroscopy

scholarly journals Quantification of the Adjacency Effect on Measurements in the Thermal Infrared Region

2019 ◽  
Vol 57 (12) ◽  
pp. 9674-9687 ◽  
Author(s):  
Xiaopo Zheng ◽  
Zhao-Liang Li ◽  
Xia Zhang ◽  
Guofei Shang
Keyword(s):  
Thermal Infrared ◽  
Infrared Region

scholarly journals Defect Related Emission in Calcium Hydroxide: The Controversial Band at 780 cm−1

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 266 ◽  
Author(s):  
Francesca Assunta Pisu ◽  
Daniele Chiriu ◽  
Pier Carlo Ricci ◽  
Carlo Maria Carbonaro
Keyword(s):  
Cultural Heritage ◽  
Calcium Hydroxide ◽  
Raman Spectra ◽  
Near Infrared ◽  
Specific Treatment ◽  
Emission Spectra ◽  
Infrared Region ◽  
Carbonation Process ◽  
Composite Band ◽  
Post Synthesis

Calcium hydroxide, a crystal involved in the cycle of calcination and carbonation of calcium oxide, finds several applications from cultural heritage to the dentistry branch or to the construction industry. When excited at 1064 nm, Raman spectra of calcium hydroxide show a broad composite band peaked at about 780 cm−1, corresponding to 1170 nm. Since it is not observed with visible excitation, the origin of this band is debated, being assigned to some pre-existent luminescent impurities or some structural defect of the lime formed after the synthesis of the material. To shed light on the formation of this band, we synthetised the lime paste starting from pure calcite powders. The obtained fresh Ca(OH)2 samples did not show any band in the investigated range, irrespective of the laser excitation applied. A detailed analysis of the excitation and emission spectra in the near infrared region did not show the 1170 nm band, supporting the hypothesis of a post-synthesis origin. Thus, we carried out thermal treatments at different temperatures (90–500 °C) and under different environments (in air or under nitrogen flux) on synthesised fresh Ca(OH)2 powders. We also investigated the time evolution of the samples, monitoring the Raman spectra over 90 days after a specific treatment. The collected data support the hypothesis of a defect-related luminescence centre, whose formation depends on the temperature and environment of the treatment, which appears as a preferential site for the carbonation process of the calcium hydroxide. These results can be useful in the field of Cultural Heritage for dating purposes, and to determine the conservation state of Ca(OH)2 containing relics to prevent the possible activation of degradation processes.

Interpretation of Data in the Thermal Infrared Region

2003 ◽  
pp. 183-216 ◽  
Author(s):  
Ravi Prakash Gupta
Keyword(s):  
Thermal Infrared ◽  
Infrared Region

The formation and detection of some low-lying excited electronic states of BrCl and other halogens

1967 ◽  
Vol 298 (1455) ◽  
pp. 424-452 ◽  
Keyword(s):  
Ground State ◽  
Near Infrared ◽  
Transfer Reaction ◽  
Potential Energy Curve ◽  
Emission Spectra ◽  
Infrared Region ◽  
Band Head ◽  
Energy Curve ◽  
Chlorine Atoms ◽  
Formula Type

Forty-nine bands arising from have been detected in the emission spectrum of from two sources: (i) the reaction of Br or Br 2 with ClO 2 , in which is populated in the transfer reaction, 3 and (ii) the radiative combination of bromine and chlorine atoms, 5 The populations of the higher levels of formed in reaction (3) are less than in reaction (5). In reaction (3), is evidently formed via a triangular transition state similar to that postulated previously; the rate constant, k 3 , was found to be The combination of ground state iodine , and chlorine atoms was also found to be chemiluminescent in the red and near infrared region, and fifty-seven bands of the system , with , have been recorded. The radiative combination of ground-state chlorine atoms has been reinvestigated, and transitions of from v ' ≼ 14 have been detected. Combining band head analyses of these emission spectra with previous data, the following constants (in cm -1 ) are reported: The reasons for the predominant radiation, during atom combination processes, from type states for Cl 2 and BrCl, and from the 3 II 1 state for ICl, are discussed in relation to Brown & Gibson’s (1932) finding of a maximum in the potential energy curve of leading to and as dissociation products.

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