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- Kasai, Y., et al.
(författare)
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Validation of stratospheric and mesospheric ozone observed by SMILES from International Space Station
- 2013
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 6:9, s. 2311-2338
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Tidskriftsartikel (refereegranskat)abstract
- We observed ozone (O3) in the vertical region between 250 and 0.0005 hPa (~ 12–96 km) using the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the Japanese Experiment Module (JEM) of the International Space Station (ISS) between 12 October 2009 and 21 April 2010. The new 4 K superconducting heterodyne receiver technology of SMILES allowed us to obtain a one order of magnitude better signal-to-noise ratio for the O3 line observation compared to past spaceborne microwave instruments. The non-sun-synchronous orbit of the ISS allowed us to observe O3 at various local times. We assessed the quality of the vertical profiles of O3 in the 100–0.001 hPa (~ 16–90 km) region for the SMILES NICT Level 2 product version 2.1.5. The evaluation is based on four components: error analysis; internal comparisons of observations targeting three different instrumental setups for the same O3 625.371 GHz transition; internal comparisons of two different retrieval algorithms; and external comparisons for various local times with ozonesonde, satellite and balloon observations (ENVISAT/MIPAS, SCISAT/ACE-FTS, Odin/OSIRIS, Odin/SMR, Aura/MLS, TELIS). SMILES O3 data have an estimated absolute accuracy of better than 0.3 ppmv (3%) with a vertical resolution of 3–4 km over the 60 to 8 hPa range. The random error for a single measurement is better than the estimated systematic error, being less than 1, 2, and 7%, in the 40–1, 80–0.1, and 100–0.004 hPa pressure regions, respectively. SMILES O3 abundance was 10–20% lower than all other satellite measurements at 8–0.1 hPa due to an error arising from uncertainties of the tangent point information and the gain calibration for the intensity of the spectrum. SMILES O3 from observation frequency Band-B had better accuracy than that from Band-A. A two month period is required to accumulate measurements covering 24 h in local time of O3 profile. However such a dataset can also contain variation due to dynamical, seasonal, and latitudinal effects
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- Pfund, B., et al.
(författare)
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UV Light Generation and Challenging Photoreactions Enabled by Upconversion in Water
- 2020
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 142:23, s. 10468-10476
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Tidskriftsartikel (refereegranskat)abstract
- Sensitized triplet-triplet annihilation (sTTA) is the most promising mechanism for pooling the energy of two visible photons, but its applications in solution were so far limited to organic solvents, with a current maximum of the excited-singlet state energy of 3.6 eV. By combining tailor-made iridium complexes with naphthalenes, we demonstrate blue-light driven upconversion in water with unprecedented singlet-state energies approaching 4 eV. The annihilators have outstanding excited-state reactivities enabling challenging photoreductions driven by sTTA. Specifically, we found that an aryl-bromide bond activation can be achieved with blue photons, and we obtained full conversion for the very energy-demanding decomposition of a persistent ammonium compound as typical water pollutant, not only with a cw laser but also with an LED light source. These results provide the first proof-of-concept for the usage of low-power light sources for challenging reactions employing blue-to-UV upconversion in water and pave the way for the further development of sustainable light-harvesting applications.
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- Schreier, M. M., et al.
(författare)
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Atmospheric parameters in a subtropical cloud regime transition derived by AIRS and MODIS : observed statistical variability compared to ERA-Interim
- 2014
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 14:7, s. 3573-3587
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Tidskriftsartikel (refereegranskat)abstract
- Cloud occurrence, microphysical and optical properties, and atmospheric profiles within a subtropical cloud regime transition in the northeastern Pacific Ocean are obtained from a synergistic combination of the Atmospheric Infrared Sounder (AIRS) and the MODerate resolution Imaging Spectroradiometer (MODIS). The observed cloud parameters and atmospheric thermodynamic profile retrievals are binned by cloud type and analyzed based on their probability density functions (PDFs). Comparison of the PDFs to data from the European Centre for Medium Range Weather Forecasting reanalysis (ERA-Interim) shows a strong difference in the occurrence of the different cloud types compared to clear sky. An increasing non-Gaussian behavior is observed in cloud optical thickness (tau(c)), effective radius (r(e)) and cloud-top temperature (T-c) distributions from stratocumulus to trade cumulus, while decreasing values of lowertropospheric stability are seen. However, variations in the mean, width and shape of the distributions are found. The AIRS potential temperature (theta) and water vapor (q) profiles in the presence of varying marine boundary layer (MBL) cloud types show overall similarities to the ERA-Interim in the mean profiles, but differences arise in the higher moments at some altitudes. The differences between the PDFs from AIRS+MODIS and ERA-Interim make it possible to pinpoint systematic errors in both systems and help to understand joint PDFs of cloud properties and coincident thermodynamic profiles from satellite observations.
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- Von Clarmann, T., et al.
(författare)
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A blind test retrieval experiment for infrared limb emission spectrometry
- 2003
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Ingår i: Journal of Geophysical Research - Atmospheres. - 2169-897X .- 2169-8996. ; 108:D23
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Tidskriftsartikel (refereegranskat)abstract
- The functionality and characteristics of six different data processors (i.e., retrieval codes in their actual software and hardware environment) for analysis of high-resolution limb emission infrared spectra recorded by the space-borne Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) have been validated by means of a blind test retrieval experiment based on synthetic spectra. For this purpose a self-consistent set of atmospheric state parameters, including pressure, temperature, vibrational temperatures, and abundances of trace gases and aerosols, has been generated and used as input for radiative transfer calculations for MIPAS measurement geometry and configuration. These spectra were convolved with the MIPAS field of view, spectrally degraded by the MIPAS instrument line shape, and, finally, superimposed with synthetic measurement noise. These synthetic MIPAS measurements were distributed among the participants of the project “Advanced MIPAS level-2 data analysis” (AMIL2DA), who performed temperature and species abundance profile retrievals by inverse radiative transfer calculations. While the retrieved profiles of atmospheric state parameters reflect some characteristics of the individual data processors, it was shown that all the data processors under investigation are capable of producing reliable results in the sense that deviations of retrieved results from the reference profiles are within the margin that is consistent with analytical error estimation.
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11. |
- Burghart, FJ, et al.
(författare)
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Muons and muonium in Zn-spinels
- 1997
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Ingår i: HYPERFINE INTERACTIONS. - : BALTZER SCI PUBL BV. - 0304-3843. ; 106:1-4, s. 187-192
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We have studied the magnetic spinel (Zn)[Fe-2]O-4 (T-N approximate to 10.5 K) and the non-magnetic spinels (Zn)[Al-2]O-4, (Zn)[Ga-2]O-4, (Zn)[ZnTi]O-4 and (Zn)[ZnSn]O-4, both with surface and decay channel muons. In (Zn)[Fe-2]O-4 the relaxation rate incre
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- D.R.Noakes, G.M.Kalvius, H.Nakotte, E.Schreier, R.Wäppling
(författare)
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mu SR magnetic response in UPdSn
- 2003
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Ingår i: Physica B. ; 326:1-4, s. 406-409
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Tidskriftsartikel (refereegranskat)
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14. |
- Ekstrom, M, et al.
(författare)
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mu SR investigation of single crystalline dysprosium
- 1997
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Ingår i: HYPERFINE INTERACTIONS. - : BALTZER SCI PUBL BV. - 0304-3843. ; 104:1-4, s. 281-285
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Muon spin rotation (mu SR) data on a single crystalline sample of Dy have been obtained as function of temperature and applied hydrostatic pressure. The discontinuity observed in our new data at the phase transition at 85 K strongly suggests that the muon
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15. |
- G.M.Kalvius, F.E.Wagner, D.R.Noakes, E.Schreier, R.Wäppling, U.Zimmermann, W.Schafer, W.Kockelmann, I.Halevy, J.Gal
(författare)
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Magnetic behavior of YFe/sub x/Al/sub 12-x
- 2003
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Ingår i: Physica B. ; 326:1-4, s. 460-464
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Tidskriftsartikel (refereegranskat)
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- Henneberger, S, et al.
(författare)
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mu SR investigations of gadolinium in the paramagnetic regime near the ferromagnetic transition
- 1997
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Ingår i: HYPERFINE INTERACTIONS. - : BALTZER SCI PUBL BV. - 0304-3843. ; 104:1-4, s. 301-306
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We report on the measurements of the muon relaxation rate in gadolinium (Gd) in the critical regime down to T - T-C = 0.1 K. The results are compared to the predictions of mode-coupling calculations for a uniaxial and dipolar ferromagnet. One observes tha
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19. |
- Kalvius, GM, et al.
(författare)
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High pressure mu SR studies: rare earths and related materials
- 2000
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Ingår i: HYPERFINE INTERACTIONS. - : BALTZER SCI PUBL BV. - 0304-3843. ; 128:1-3, s. 275-303
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Tidskriftsartikel (refereegranskat)abstract
- After a short introduction to mu SR with respect to the study of magnetic properties, followed by a brief outline of the principle of the high pressure-low temperature mu SR spectrometer installed at the Paul Scherrer Institute, we discuss some measuremen
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- Kalvius, G. M., et al.
(författare)
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Study of magnetic clusters in granular CoxCu1- x
- 2008
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Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 77:2, s. 025705-
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Tidskriftsartikel (refereegranskat)abstract
- Samples of CoxCu1-x (x = 0.05, 0.02 and 0.01) produced by melt spinning and subsequent annealing were studied by muon spin rotation/relaxation (mu SR) spectroscopy with the aim to gain information on the dependence of the local magnetic properties like the magnitude, the distribution and the temporal behavior of the magnetic field at the muon site as function of Co concentration. In addition, we investigated for Co0.02Cu0.98 the changes in mu SR response as function of annealing times and temperatures. In all alloys, a spin-glass-like magnetic cluster state was seen well below the susceptibility cusp temperature. Above this temperature, cluster spin dynamics sets in but with low fluctuation rates even at high temperatures reflecting the presence of strong cluster - cluster couplings. A free paramagnetic cluster state is not formed. Spin dynamic properties are different for the x = 0(05 and 0.02 compounds and the x = 0(01 alloy. In the former compounds, the coexistence of a slower and a faster fluctuating fraction is found, arising from a non-uniform cluster size distribution or a non-random spatial distribution of clusters. In the latter compound, the spin dynamical state is homogeneous, but shows an unusual mu SR response requiring the presence of simultaneous fluctuations in spin orientation and moment magnitude. It further points to the presence of a partial loss of magnetic clusters. The variation of annealing times and temperatures for Co0.02Cu0.98 influences details of mu SR spectral parameters but leaves the overall response the same.
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- Schreier, E, et al.
(författare)
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High-pressure mu SR studies on elemental rare earth metals
- 2000
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Ingår i: PHYSICA B. - : ELSEVIER SCIENCE BV. - 0921-4526. ; 289, s. 244-247 Language: English
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Tidskriftsartikel (refereegranskat)abstract
- Muon-spin rotation data on single-crystalline samples of the heavy rare-earth metals Dy and Ho in their antiferromagnetic and ferromagnetic temperature regimes (20 K < T < T-N) have been obtained as function of hydrostatic external pressure up to 0.9 GPa
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29. |
- Schreier, E, et al.
(författare)
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High pressure mu SR studies on single crystalline gadolinium
- 1997
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Ingår i: HYPERFINE INTERACTIONS. - : BALTZER SCI PUBL BV. - 0304-3843. ; 104:1-4, s. 311-317
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Muon spin rotation data on a single crystalline gadolinium sample have been obtained as function of temperature and hydrostatic external pressure up to 0.6 GPa. In the ferromagnetic state the application of pressure has a strong influence on the whole spi
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30. |
- Schreier, E, et al.
(författare)
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Internal fields in magnetically ordered dysprosium, holmium and erbium
- 2000
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Ingår i: PHYSICA B. - : ELSEVIER SCIENCE BV. - 0921-4526. ; 289, s. 240-243
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Tidskriftsartikel (refereegranskat)abstract
- Muon spin rotation data on single-crystalline samples of the heavy rare earth metals Dy, Ho and Er have been obtained as function of temperature in both the antiferromagnetic (afm) and the ferromagnetic (fm) state. In the afm state the temperature depende
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