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  • 1
    Publikationsdatum: 2022-05-25
    Beschreibung: Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 9 (2008): Q02016, doi:10.1029/2007GC001800.
    Beschreibung: The utility of elemental mapping by scanning X-ray fluorescence (XRF) in the study of annual laminated sedimentary records was investigated on eight annually laminated sediment types. The examples were chosen to illustrate the potential of this approach in environments dominated by terrigenous, biological and chemical deposition. Individual laminae were identifiable in elemental maps of all sediment types and were enhanced through the use of data reduction techniques (e.g., principal components transformation). Laminae were least apparent in clastic dominated systems with no seasonal changes in sediment sources. In biologically dominated systems, element maps provided insights into the composition of the varve subcomponents, related to alternating terrigenous and biologically dominated seasonal periods of deposition. Chemically precipitated structures were more prevalent than expected from visual investigations alone and may provide an underutilized paleoenvironmental signature of changing limnological conditions. Elemental mapping offers a valuable tool for the study of laminated records that complements existing techniques (e.g., SEM, digital image analysis).
    Beschreibung: Funding was provided through NSF Earth System History grants and an NSF Instrumentation grant awarded to J.T.O.
    Schlagwort(e): Micro-XRF scanner ; Major elements ; Varve ; Lamination
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2020-02-12
    Beschreibung: Due to the strong interest in geochemical CO2-fluid-rock interaction in the context of geological storage of CO2 a growing number of research groups have used a variety of different experimental ways to identify important geochemical dissolution or precipitation reactions and – if possible – quantify the rates and extent of mineral or rock alteration. In this inter-laboratory comparison the gas-fluid-mineral reactions of three samples of rock-forming minerals have been investigated by 11 experimental labs. The reported results point to robust identification of the major processes in the experiments by most groups. The dissolution rates derived from the changes in composition of the aqueous phase are consistent overall, but the variation could be reduced by using similar corrections for changing parameters in the reaction cells over time. The comparison of experimental setups and procedures as well as of data corrections identified potential improvements for future gas-fluid-rock studies.
    Materialart: info:eu-repo/semantics/article
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Publikationsdatum: 2020-10-12
    Beschreibung: This report documents the acquisition and archiving of a major 3D active-source and passive seismic imaging experiment, NZ3D-FWI. The NZ3D-FWI project aims to image the Hikurangi subduction zone (upper and lower plates and plate boundary fault) along the north Hikurangi margin where shallow slow slip events occur. The primary aim of the project is to collect data optimally to produce high-resolution velocity models using Full-waveform inversion (FWI). The deployment, servicing and collection of the NZ3D-FWI onshore instruments between December 2017 and October 2018 was conducted by Imperial College London, GNS Science, Cardiff University, University of Southampton and Victoria University of Wellington. A 15 x 60 km volume of 3D seismic reflection data was collected offshore of Gisborne by the R/V Marcus Langseth, funded by the National Science Foundation (NSF, USA), the Natural Environment Research Council (NERC, UK) and GNS Science. 99 ocean bottom seismographs were deployed in the 3D seismic reflection volume footprint by JAMSTEC and GNS Science. The onshore NZ3D-FWI deployment included 49 CMG-6TD broadband seismometers from NERC SEIS-UK, which were deployed from December 2017 to October 2018 and detected airgun shots from the 3D seismic reflection survey and local and teleseismic earthquakes over the nine-month period. 119 short-period DATA-CUBE3 instruments loaned from the German Instrument Pool Potsdam (GIPP), and 25 short-period GSX3 instruments from the Earthquake Research Institute (ERI), Tokyo, were deployed between December 2017 and February 2018. These recorded airgun sources and seismicity over a two-month period. The deployment involved a broader array (the Gisborne array), which covered an area of 15 x 30 km with an instrument spacing of ∼2 km. These instruments will primarily be used to construct a high-resolution onshore-offshore velocity model in conjunction with the data collected by the offshore instruments. A denser array of instruments (the Waimata Valley array) with spacing of ∼500 m is aimed at understanding mud volcano processes using active and passive source methods.
    Sprache: Englisch
    Materialart: info:eu-repo/semantics/report
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 3519-3538 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: Cyanogen iodide (ICN) is photodissociated at 249 nm. The CN X 2Σ+ photofragment is probed by sub-Doppler laser-induced fluorescence (LIF), allowing the extraction of recoil velocity anisotropies and branching ratios to the two iodine atom spin–orbit states I(2P1/2) and I(2P3/2) as a function of the CN (v=0) rotational state. The quantum yield for I(2P1/2) production ΦI* is found to be 43%±3%, in excellent agreement with the recent diode laser spectroscopic measurement of Hess and Leone. The population of the F1 and F2 spin–rotation doublet components shows nonstatistical behavior over a wide range of N for both I atom spin–orbit state exit channels. The results suggest that trajectories leading to I(2P1/2) evolve on an essentially collinear surface; the CN fragments being found in low rotational levels with almost limiting values of the system anisotropy parameter (β=1.85 to 1.9). This value of β yields an estimate for the dissociative lifetime [CN X 2Σ+v=0, N=0; I(2P1/2)] of 90±15 fs at this photolysis wavelength. There is evidence that trajectories leading to I(2P1/2)+CN(v=0) in intermediate N levels have sampled a bent surface, indicating that multiple curve crossings occur in this channel. The nature of trajectories correlated to I(2P3/2) is very complicated, with clear evidence for a mixed parallel and perpendicular initial transition and subsequent curve crossings. The CN (v=0) fragments formed in conjunction with this channel are found predominantly in medium to high rotational quantum states. The system anisotropy parameters vary as a function of N, being negative at low N and becoming positive at high N. An analysis of the correlation between fragment velocity and rotation yields results inconsistent with a pure parallel or perpendicular excitation. We present a model involving three interacting surfaces, by which we can reconcile all major experimental observations at this photolysis wavelength.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 98 (1993), S. 6853-6868 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: Cyanogen iodide (ICN) has been photodissociated at 249 nm. The CN(X 2Σ+) photofragments were probed by laser induced fluorescence (LIF) using multiple distinct excitation–detection geometries, allowing the extraction of bipolar moments describing the distribution and mutual correlations of the fragment velocity, angular momentum, and dipole moment vectors. The results of this analysis are consistent with three optically active transitions at this photolysis wavelength, one with parallel character and two with perpendicular character. One of these perpendicular transitions has the direction of the transition dipole moment perpendicular to the plane of the three atoms, whereas the other has the transition moment in the plane of the three atoms, perpendicular to the I–C bond. This picture can be reconciled with recent ab initio calculations of the level structure of the ICN A˜–X˜ continuum and can also be used as a framework to explain in a consistent manner many of the gross features of the photodissociation dynamics of ICN observed in previous experiments at this wavelength.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 2755-2761 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A compact, high-peak-power, user-friendly, single-longitudinal-mode (SLM) tunable dye laser has been developed. The device yields (approximately-greater-than)12 mJ pulses of 6 ns duration and ∼2.7×transform-limited linewidths of 〈200 MHz. Seamless single-mode tunability of (approximately-greater-than)20 cm−1 is possible without resetting. The dye laser makes efficient use of the pump laser, with ∼10% conversion of the 532 nm pump energy to tunable dye power and occupies 〈4 m2 (including pump laser and all diagnostics). The linewidth of the device can be switched from 〈200 MHz SLM operation to 〈0.5 cm−1 broadband modeless operation by moving one mirror. This allows rapid interchange between high-resolution scanning and a "fast survey scan'' mode of operation to isolate the spectral region of interest at low resolution.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 23 (1968), S. 0 
    ISSN: 1365-2494
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: In two experiments the growth of clover undersown to wheat was linearly related to the amount of light available. There were strong indications that clover growth and light within N.-S. rows were superior to those within E.-W. rows of wheat, and within N.-S. rows, those along the middle position were superior to others. The large difference between the growth of clover sown alone and with wheat indicated that beneath wheat the clover suffered from competition for other factors, probably soil moisture, which was even greater than that for light. Beneath wheat at the reduced level of growth there was a positive linear relationship between yield of clover and available light.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    ISSN: 1365-2494
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: The distribution of leaf area and light intensity within wheat crops differing in row direction, row spacing and rate of sowing is described. Regardless of the manner of planting, 75% of the total leaf area was found within a band 31/2 in. wide, centred on the centre of the row. Light penetration within crops spaced at 14 in. was greater than within those spaced at 7 in. Light penetration within rows running N.–S. was more uniform and higher, particularly around noon, than within rows running E.-W. Within N.-S. rows the position midway between rows received the highest amount of light, but light decreased on either side until it was least beneath the rows. Within E.-W. rows at 14 in. spacing, maximum light was recorded at 101/2 in. on the southern side of a row, decreasing progressively as the row was approached.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 22 (1967), S. 0 
    ISSN: 1365-2494
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Sowing pasture species with wheat caused a reduction in the growth and yield of the pasture species. This reduction was more severe with wheat drilled at 7 inch row spacing than at 14 in., and was least when the two crops were in alternate 7 in. rows. The reduction appeared to be due principally to the shade cast by the wheat. The pasture also reduced the growth and yield of wheat, but the effect of row spacing and position were opposite to and very much less marked than those of wheat on pasture. The yield of the pasture early in the following season was related to the seed yields in the year of establishment; later in the season, however, differences in yield among the various treatments disappeared.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Analytical chemistry 21 (1949), S. 554-559 
    ISSN: 1520-6882
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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