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1.
The kinetics of the aqueous phase reactions of NO3 radicals with HCOOH/HCOO– and CH3COOH/CH3COO– have been investigated using a laser photolysis/long-path laser absorption technique. NO3 was produced via excimer laser photolysis of peroxodisulfate anions (S2O
8
2–
) at 351 nm followed by the reactions of sulfate radicals (SO
4
–
) with excess nitrate. The time-resolved detection of NO3 was achieved by long-path laser absorption at 632.8 nm. For the reactions of NO3 with formic acid (1) and formate (2) rate coefficients ofk
1=(3.3±1.0)×105 l mol–1 s–1 andk
2=(5.0±0.4)×107 l mol–1 s–1 were found atT=298 K andI=0.19 mol/l. The following Arrhenius expressions were derived:k
1(T)=(3.4±0.3)×1010 exp[–(3400±600)/T] l mol–1 s–1 andk
2(T)=(8.2±0.8)×1010 exp[–(2200±700)/T] l mol–1 s–1. The rate coefficients for the reactions of NO3 with acetic acid (3) and acetate (4) atT=298 K andI=0.19 mol/l were determined as:k
3=(1.3±0.3)×104 l mol–1 s–1 andk
4=(2.3±0.4)×106 l mol–1 s–1. The temperature dependences for these reactions are described by:k
3(T)=(4.9±0.5)×109 exp[–(3800±700)/T] l mol–1 s–1 andk
4(T)=(1.0±0.2)×1012 exp[–(3800±1200)/T] l mol–1 s–1. The differences in reactivity of the anions HCOO– and CH3COO– compared to their corresponding acids HCOOH and CH3COOH are explained by the higher reactivity of NO3 in charge transfer processes compared to H atom abstraction. From a comparison of NO3 reactions with various droplets constituents it is concluded that the reaction of NO3 with HCOO– may present a dominant loss reaction of NO3 in atmospheric droplets. 相似文献
2.
Ohne Zusammenfassung 相似文献
3.
Christof Exner 《Mineralogy and Petrology》1954,4(1-4):312-319
Ohne ZusammenfassungMit 3 Textabbildungen. 相似文献
4.
Roy F. Spalding Aaron J. Hirsh Mary E. Exner Marty Stange Ramon Aravena 《Ground Water Monitoring & Remediation》2019,39(2):22-31
Identification of major nitrate sources that adversely impact groundwater quality in municipal well capture zones in areas of emerging nitrate contamination is essential to minimize leaching and prevent exceedance of the nitrate drinking water standard. Vertical profiles of nitrate leachate in deep soils provide an estimate of the amount of nitrate in transit beneath irrigated, row-cropped fields; depths of peak leachate; and the approximate rate of downward movement. Profiles of pore-water soil-nitrate concentrations in thick 60-feet (~18 m), fine-textured soils near Hastings, Nebraska clearly indicate that considerably more nitrate leached beneath furrow-irrigated than center-pivot irrigated fields. Peak leaching appeared to correlate with recorded periods of poor weather conditions during some growing seasons and may best be controlled by “spoon feeding” fertilizer to the crop through the sprinkler irrigation system at times of nutrient need. The presence of trace levels of atrazine and deethylatrazine to 60 feet (18 m) in core samples indicates that larger, more complex anthropogenic molecules also leach through the fine-textured soils. The light δ15NNO3 values in the surficial groundwater beneath fertilized and irrigated cropland indicate that ammonium fertilizer is a major N source and suggest that the natural soil-N contribution is negligible. δ15NNO3 values were most enriched in irrigation wells located within municipal well capture zones downgradient of a large feedlot. Dual isotope method (DIM) δ15NNO3 and δ18ONO3 values suggest that the Hastings’ municipal wells farther downgradient are contaminated with a mixture of nitrate from manure and commercial ammonium-based fertilizer. DIM values indicate an absence of denitrification, which has implications for long-term management of the water resources. 相似文献
5.
Listric versus planar normal fault geometry: an example from the Eisenstadt-Sopron Basin (E Austria) 总被引：1，自引：0，他引：1
Darko Spahić Ulrike Exner Michael Behm Bernhard Grasemann Alexander Haring Herbert Pretsch 《International Journal of Earth Sciences》2011,100(7):1685-1695
In a gravel pit at the eastern margin of the Eisenstadt-Sopron Basin, a satellite of Vienna Basin (Austria), Neogene sediments
are exposed in the hanging wall of a major normal fault. The anticlinal structure and associated conjugated secondary normal
faults were previously interpreted as a rollover anticline above a listric normal fault. The spatial orientation and distribution
of sedimentary horizons and crosscutting faults were mapped in detail on a laser scan of the outcrop wall. Subsequently, in
order to assess the 3D distribution and geometry of this fault system, a series of parallel ground penetrating radar (GPR)
profiles were recorded behind the outcrop wall. Both outcrop and GPR data were compiled in a 3D structural model, providing
the basis for a kinematic reconstruction of the fault plane using balanced cross-section techniques. However, the kinematic
reconstruction results in a geologically meaningless normal fault cutting down- and up-section. Additionally, no evidence
for a weak layer serving as ductile detachment horizon (i.e. salt or clay horizon) can be identified in stratigraphic profiles.
Instead, the observed deflection of stratigraphic horizons may be caused by a displacement gradient along a planar master
fault, with a maximum displacement in the fault centre, decreasing towards the fault tips. Accordingly, the observed deflection
of markers in the hanging wall—and in a nearby location in the footwall of the normal fault—is interpreted as large-scale
fault drag along a planar fault that records a displacement gradient, instead of a rollover anticline related to a listric
fault. 相似文献
6.
Ohne Zusammenfassung 相似文献
7.
Many problems in geology, especially structural geology, can only be solved by detailed mapping. Presently, mapping is still
mainly carried out on paper using techniques from the 19th Century. However, tools are now available to carry out most mapping tasks on microcomputers in the field without any need
of paper. This speeds up geological mapping and reduces the errors involved in the mapping process. Digital mapping also allows
work in featureless areas and areas of great structural complexity that would not be possible using paper maps. We present
two practical examples of the new technology of digital mapping using microcomputers, from Namibia and Greece. 相似文献
8.
Ch. Exner E. Schroll G. Pantó J. Zemann H. Wieseneder F. Machatschki 《Mineralogy and Petrology》1968,12(4):479-488
Ohne Zusammenfassung 相似文献
9.
W. Medwenitsch H. Wieseneder Ch. Exner K. Becherer W. Kaltenegger R. Fischer F. Machatschki 《Mineralogy and Petrology》1966,11(1-2):165-170
Ohne Zusammenfassung 相似文献
10.
Prof. Dr. Christof Exner 《Mineralogy and Petrology》1966,11(3-4):358-372
Summary Some types of Allanite (Orthite) are here described. They are found as assessory minerals in the rocks of the Hohe Tauern (penninic zone of the Eastern Alps) and in the hercynian foreland (Bohemian Massif). We distinguish Allanite I, II and III.The Allanite I (Hohe Tauern) is not isotropisized, but currently idiomorphic, with a xenomorphic rim of Clinozoisite. Where Allanite I is bordering Quartz or Potassium feldspar there is generally no rim of Clinozoisite. In the tectonites one observes granulated Allanite I and transformation of Allanite I to finegranied aggregates of Clinozoisite.Allanite II (Hohe Tauern) is found in intensely radioactive rocks. It is currently isotropisized, xenomorphic and surrounded by xenomorphic rims of Pistacite.Allanite III (Bohemian Massif) may be the oldest one and it is mostly isotropisized.The problems of the genesis and the age of crystallisation of Allanite during the history of our polymetamorphic rocks are shortly touched.
Mit 11 Textabbildungen
Herrn Prof. Dr.H. Leitmeier zum 80. Geburtstag gewidmet. 相似文献
Mit 11 Textabbildungen
Herrn Prof. Dr.H. Leitmeier zum 80. Geburtstag gewidmet. 相似文献