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  • 11
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    SMILES diurnal variation climatology of strato- and mesospheric trace gases: O3, HCl, HNO3, ClO, BrO, HOCl, HO2, and temperature (2014)
    In:  EPIC3SPARC General Assembly 2014, Queenstown, New Zealand, 2014-01-12-2014-01-17
    Details
    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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  • 12
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    Direct estimation of the rate constant of the reaction ClO + HO2 → HOCl + O2 from SMILES atmospheric observations (2014)
    In:  EPIC3Atmospheric Chemistry and Physics, 14, pp. 255-266
    Details
    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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  • 13
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    Breakthrough in purification of fossil pollen for dating of sediments by a new large-particle on-chip sorter (2021)
    In:  Science Advances
    Details
    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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  • 14
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    The GOSAT-GW satellite mission: Potential roles in quantifying greenhouse gases and air pollutants emissions from local to global scales (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    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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  • 15
    Electronic Resource
    Electronic Resource
    Effect of additives on thermal stability of Nd-Fe-B bonded magnets (abstract) : 38th Annual Conference on Magnetism and Magnetic Materials (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 6658-6658 
    Details
    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
    URL: http://dx.doi.org/10.1063/1.356886
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  • 16
    Electronic Resource
    Electronic Resource
    Superconducting photorelaxation spectroscopy (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 1714-1721 
    Details
    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
    URL: http://dx.doi.org/10.1063/1.339907
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  • 17
    Electronic Resource
    Electronic Resource
    Effect of additive elements on magnetic properties and irreversible loss of hot-worked Nd-Fe-Co-B magnets : 35th annual conference on magnetism and magnetic materials (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 6049-6051 
    Details
    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
    URL: http://dx.doi.org/10.1063/1.347766
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  • 18
    Electronic Resource
    Electronic Resource
    Low rare-earth Nd–Fe–B bonded magnets with improved irreversible flux loss : The 41st annual conference on magnetism and magnetic materials (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 4447-4449 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of Nb addition on magnetic properties and irreversible flux loss were studied on bonded magnets with compositions of Nd8Fe86−xB6Nbx, where x=0–3. An irreversible flux loss was measured at Pc=2 after exposure at 393 K for 3.6 ks in air. It was found that the Nb addition of 2 at. % or more decreased the irreversible flux loss. The value was less than 5%, similar to that obtained with MQP-B magnets. Br decreased with the increase in Nb content. The effect of Nd content on the magnetic properties and irreversible flux loss was also studied on the bonded magnets with compositions of NdxFe92−xB6Nb2, where x=6–8. The bonded magnet with the optimum composition of Nd6.5Fe85.5B6Nb2 had Br similar to that of MQP-Q magnets that did not contain Nb, and the value of irreversible flux loss was comparable to that of MQP-B magnets. A multipole magnetizability test on the bonded magnets with the above optimum composition was carried out, and the total flux of the bonded magnets was about 10% higher than that of MQP-B magnets for the 23 mm outside diameter magnet with 48 poles. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.364971
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  • 19
    Electronic Resource
    Electronic Resource
    Hot workability of melt-spun Nd-Fe-Co-B magnets : 35TH ANNUAL CONFERENCE ON MAGNETISM AND MAGNETIC MATERIALS San Diego, California (USA) 29 Oct−1 Nov 1990 (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 5841-5843 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Anisotropic Nd-Fe-B magnets are produced from melt-spun ribbons by hot working technique. The processing is facilitated by improved workability. In order to obtain a sound magnet, it is important to suppress the crack initiation and growth. An investigation was carried out to study the deformation mechanism of the alloy system and to improve workability by changes in alloy composition. Alloy ribbons with composition (Nd13.6−xRx) (Fe77.6−y Ty Co2.8)B6.0 [R=Ce, Dy; T=Al, Si, V, Cu, Ga, Zr, Nb, Mo, Sn; x= 0, 1, 2; y=0, 0.5, 1.0] were prepared by melt spinning and then hot pressed into fully dense compacts. These compacts were upset in a hot working simulator. Hot workability was evaluated by measuring the crack opening displacement on the surface at the half height of the upset specimen. The relationship between strain rate and flow stress was found to be expressed by the equation: ε(overdot) = Aσn exp( − Q/RT). Values of n and Q were obtained for quarternary composition (Nd-Fe-Co-B). The effects of strain and strain rate on magnetic properties were also studied for quarternary composition. Of the additive elements, cerium and silicon addition showed significant improvement in workability without loss of coercivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347844
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  • 20
    Electronic Resource
    Electronic Resource
    Effect of additives on hot deformation behavior of melt-spun Nd-Fe-Co-B magnets : The 5th Joint MMM−Intermag Conference (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 6363-6365 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of various additives on hot workability was investigated for alloy systems of (Nd13.6−xRx)(Fe77.6−yTyCo2.8)B6.0: R=Ce, Dy; x=0, 1, 2; T=Al, Si, V, Cu, Ga, Zr, Nb, Mo, Sn; y=0, 0.5, 1.0. A semiquantitative comparison of the effect of various additives was made by measuring the crack opening displacement (CODmax) in test specimens deformed in an open (unconstrained) configuration. Among the additives, cerium and silicon improved the hot workability while niobium and tin severely deteriorated the workability. The remanence anisotropy ratio was inversely related to CODmax. Detailed microstructural investigations were carried out with alloys which had only cerium or tin to study the reason for their hot workability behavior in comparison to the base alloy. The improved hot workability of cerium added alloy is related to the lower melting temperature of the intergranular phase and faster grain growth compared to the base alloy. Tin addition prevented grain growth with no endothermic peak in a differential thermal analysis curve, indicating the absence of boundary phase melting, and leading to poor hot workability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.349943
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