6 research outputs found
First-principles study of Berry curvature and intrinsic anomalous Hall conductivity in ferromagnetic materials using Maximally localized Wannier function
Electronic properties for bcc Fe and hcp Co in bulk state and also Fe-Co alloy were calculated by quantum calculation based on density functional theory and pseudopotential method. Combination of Wannier function and Berry phase theory was used for calculation of anomalous Hall conductivity in above structures. It was seen that split of band by the spin orbit interaction, lying on the Fermi level, has a major role in Berry curvature. Acquired results agree with experimental ones and thus it seems that conductivity in bulk state is intrinsic
Strain effects on the magnetic anisotropy of Y2Fe14B examined by first-principles calculations
OMI air-quality monitoring over the Middle East
Using Ozone Monitoring Instrument (OMI) trace gas vertical column
observations of nitrogen dioxide (NO2), formaldehyde (HCHO), sulfur
dioxide (SO2), and glyoxal (CHOCHO), we have conducted a robust and
detailed time series analysis to assess changes in local air quality for over
1000 locations (focussing on urban, oil refinery, oil port, and power
plant targets) over the Middle East for 2005–2014. Apart from NO2, which
is highest over urban locations, average tropospheric column levels of these
trace gases are highest over oil ports and refineries. The highest average
pollution levels over urban settlements are typically in Bahrain, Kuwait,
Qatar, and the United Arab Emirates.
We detect 278 statistically significant and real linear NO2 trends in
total. Over urban areas NO2 increased by up to 12 % yr−1, with
only two locations showing a decreasing trend. Over oil refineries, oil
ports, and power plants, NO2 increased by about 2–9 % yr−1. For
HCHO, 70 significant and real trends were detected, with HCHO increasing by
2–7 % yr−1 over urban settlements and power plants and by about
2–4 % yr−1 over refineries and oil ports. Very few SO2 trends
were detected, which varied in direction and magnitude (23 increasing and 9
decreasing). Apart from two locations where CHOCHO is decreasing, we find
that glyoxal tropospheric column levels are not changing over the Middle East.
Hence, for many locations in the Middle East, OMI observes a degradation in
air quality over 2005–2014. This study therefore demonstrates the capability
of OMI to generate long-term air-quality monitoring at local scales over this
region