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  • 1
    Publication Date: 2019-07-17
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 2
    Publication Date: 2019-07-17
    Description: This paper presents extensive {bias determination} analyses of ozone observations from the Atmospheric Chemistry Experiment (ACE) satellite instruments: the ACE Fourier Transform Spectrometer (ACE-FTS) and the Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (ACE-MAESTRO) instrument. Here we compare the latest ozone data products from ACE-FTS and ACE-MAESTRO with coincident observations from nearly 20 satellite-borne, airborne, balloon-borne and ground-based instruments, by analysing volume mixing ratio profiles and partial column densities. The ACE-FTS version 2.2 Ozone Update product reports more ozone than most correlative measurements from the upper troposphere to the lower mesosphere. At altitude levels from 16 to 44 km, the average values of the mean relative differences are nearly all within +1 to +8%. At higher altitudes (4560 km), the ACE-FTS ozone amounts are significantly larger than those of the comparison instruments, with mean relative differences of up to +40% (about +20% on average). For the ACE-MAESTRO version 1.2 ozone data product, mean relative differences are within ±10% (average values within ±6%) between 18 and 40 km for both the sunrise and sunset measurements. At higher altitudes (~3555 km), systematic biases of opposite sign are found between the ACE-MAESTRO sunrise and sunset observations. While ozone amounts derived from the ACE-MAESTRO sunrise occultation data are often smaller than the coincident observations (with mean relative differences down to −10%), the sunset occultation profiles for ACE-MAESTRO show results that are qualitatively similar to ACE-FTS, indicating a large positive bias (mean relative differences within +10 to +30%) in the 4555 km altitude range. In contrast, there is no significant systematic difference in bias found for the ACE-FTS sunrise and sunset measurements.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 3
    Publication Date: 2019-07-17
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
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  • 4
    Publication Date: 2019-07-17
    Description: We have made a climatology of the diurnal variation of short-lived atmospheric compounds, such as ClO, BrO, HO2, and HOCl, as well as longer life time longer-lived species: O3, the hydrogen chloride isotopes H35Cl and H37Cl, and HNO3 from measurements by the Superconducting SubMIllimeter9 wave Limb-Emission Sounder (SMILES) on International Space Station (ISS). We performed the observation with very low noise on the emission spectrum for measuring of vertical profiles of atmospheric compositions with altitude range from the lower stratosphere to the lower thermosphere (20 – 100 km), thus observing at all local times due to a non-sun-synchronous orbit of ISS. The diurnal variation climatologies are based on data periods of two months. Consideration of the SMILES time-space sampling patterns with respect to the averaging coordinates is a key issue for climatology creation. Biases induced by inhomogeneous sampling are minimized by carefully choosing the size of averaging bins. The sampling biases of the diurnal variation climatology of ClO and BrO are investigated in a comparison of homogeneously sampled model data versus SMILES sampled model data from the stratospheric Lagrangian chemistry and transport model ATLAS. Mostly the relative error is in the range of 0 – 20%.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 5
    Publication Date: 2019-07-17
    Description: Diurnal variations of ClO, HO2, and HOCl were simultaneously observed by the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) between 12 October 2009 and 21 April 2010. These were the first global observations of the diurnal variation of HOCl in the upper atmosphere. A major reaction for the production of HOCl is ClO + HO2 → HOCl + O2 (Reaction (R1)) in extra-polar regions. A model study suggested that in the mesosphere, this is the only reaction influencing the amount of HOCl during the night. The evaluation of the pure reaction period, when only Reaction (R1) occurred in the Cly chemical system, was performed by checking the consistency of the HOCl production rate with the ClO loss rate from SMILES observation data. It turned out that the SMILES data at the pressure level of 0.28 hPa (about 58 km) in the autumn mid-latitude region (20–40°, February–April 2010) during night (between modified local time 18:30 and 04:00) were suitable for the estimation of the rate constant, k1. The rate constant obtained from SMILES observations was k1(245 K) = (7.75 ± 0.25) × 10−12 cm3 molecule−1 s−1. This result is consistent with results from a laboratory experiment and ab initio calculations for similar low-pressure conditions.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 6
    Publication Date: 2022-09-27
    Description: Particle sorting is a fundamental method in various fields of medical and biological research. However, existing sorting applications are not capable for high-throughput sorting of large-size (〉100 micrometers) particles. Here, we present a novel on-chip sorting method using traveling vortices generated by on-demand microjet flows, which locally exceed laminar flow condition, allowing for high-throughput sorting (5 kilohertz) with a record-wide sorting area of 520 micrometers. Using an activation system based on fluorescence detection, the method successfully sorted 160-micrometer microbeads and purified fossil pollen (maximum dimension around 170 micrometers) from lake sediments. Radiocarbon dates of sorting-derived fossil pollen concentrates proved accurate, demonstrating the method’s ability to enhance building chronologies for paleoenvironmental records from sedimentary archives. The method is capable to cover urgent needs for high-throughput large-particle sorting in genomics, metabolomics, and regenerative medicine and opens up new opportunities for the use of pollen and other microfossils in geochronology, paleoecology, and paleoclimatology.
    Type: info:eu-repo/semantics/article
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  • 7
    Publication Date: 2023-07-07
    Description: Complementing the bottom-up methods, the emissions inventories of chemical species of climatic and environmental importance can be derived using atmospheric inverse models, providing integrated constraints on surface fluxes from all sectors/processes. For these models a variety of observations are used, including those from ground-based, ship, aircraft and satellite platforms. In particular, recent improvements in the capability of satellite observations of greenhouse gases (GHGs) and air quality (AQ) are providing great advances on spatial resolutions. Among several plans to launch the GHGs and/or AQ observing satellites in near future, a plan is in progress in Japan to launch the “Global Observing SATellite for Greenhouse gases and Water cycle (GOSAT-GW)”, that will make observations of carbon dioxide (CO〈sub〉2〈/sub〉), methane (CH〈sub〉4〈/sub〉), and nitrogen dioxide (NO〈sub〉2〈/sub〉) at a horizontal resolution of 3 km or less. The missions of GOSAT-GW include (1) monitoring of whole atmosphere-mean concentrations of GHGs, (2) validation of nationwide anthropogenic emissions of GHGs, and (3) detection of GHGs emissions from large sources, such as megacities and power plants. We will provide an overview of the mission/project and some highlights on the potential roles in quantifying anthropogenic emissions from local to global scales, supporting the mitigation policies on climate change as well as air quality at both international and national levels.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 6658-6658 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Effects of Zr and Nb on magnetic properties and thermal stability were studied for Nd-Fe-B bonded magnets. Bonded magnets with a composition of Ndx(Fe94-x-y)B6Ty, where T=Zr and Nb; x=11.0, 11.5, and 12.0; y=0, 0.5, 1.0, 1.5, and 2.0; were prepared by using melt spun ribbons. The addition of Zr up to 0.5 at .% increased the (BH)max of the bonded magnets, and further addition of Zr decreased the (BH)max at each Nd content level. Hci increased monotonously with an increase in Zr. (BH)max and Hci of the Nb containing bonded magnets also showed similar behavior. Irreversible flux loss after exposure at 180 °C for 1000 h significantly reduced with an increase in the Zr content at each Nd content level. Both the structural flux loss and the thermal fluctuation flux loss were reduced with an increase in the Zr content. An irreversible flux loss of about 5% was obtained when the Nd and Zr content were 11.5 at .% and 2.0 at. %, respectively. A similar value of irreversible flux loss was also obtained in Nb containing bonded magnets with the same composition. It was found that the oxygen pickup by the bonded magnets during the heat resistant test was well correlated to the structural loss of the bonded magnets. A structural flux loss of less than 3% was obtained when the oxygen pickup was less than 0.4 wt. % for both additives. SEM studies revealed that the grain size of the 2-14-1 phase observed in the additive-containing specimens was finer than that of the base alloy.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 1714-1721 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A novel technique termed superconducting photorelaxation spectroscopy is described in detail which utilizes a superconducting tunnel junction for detection of phonons from optically illuminated semiconductors. The method makes use of a lock-in, highly sensitive, detection technique which allows for direct detection of phonons. The system noise is suppressed to the level of 100 pV, enabling one to detect the phonon signal with an S/N ratio of 104. It is demonstrated that the phonon signal detected does not depend upon the chopper frequency, in contrast to conventional photoacoustic spectroscopy. The phonon signal as a function of wavelength of light employing a silver optical reflector yields a clear band-gap structure and modulated structures in the deep-level region consistent with the measurements obtained by other techniques for GaAs and InP wafers. The model for the phonon-detection system with its associated sensitivity is presented. It appears this method will be a very promising technique to study the nonradiative states of semiconductor crystals.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: There has been limited work on the effects of alloying elements on the properties of hot-worked anisotropic magnets. The coercivity mechanisms for sintered and rapidly solidified Nd-Fe-B magnets are different, and additives can have different effects on magnetic properties. The present study was conducted to clarify the effects of various alloying elements on the properties of hot-worked magnets. Ribbons of composition (Nd13.6−xRx)(Fe77.6−yTyCo2.8)B6.0 (R=Ce and Dy; T=Al, V, Cu, Ga, Zr, Nb, Mo, and Sn; x=0, 1, and 2; y=0, 0.5, and 1.0) were prepared by melt spinning. Anisotropic magnets were made at 1073 K with 55.6% reduction in height by die upsetting. Room-temperature magnetic properties and irreversible losses after exposure at 323–473 K were determined. The results showed that small amounts of Al, V, Cu, and Ga enhanced the remanence of the magnets, while Dy, Al, Ga, Zr, Nb, and Mo improved the coercivity. Dy, Ga, and Mo additions were effective in increasing the heat resistance temperature (HRT), defined as the temperature where the irreversible loss is 3%. HRT is dependent on initial intrinsic coercivity and the squareness ratio (Hk/iHc) of the demagnetization curve. An equation relating these parameters is given. An HRT of 453 K was obtained with a suitable alloy composition.
    Type of Medium: Electronic Resource
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