19,242 research outputs found
Adaptive Neural Network Feedforward Control for Dynamically Substructured Systems
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Impact intensities of climatic changes on grassland ecosystems in headwater areas
Rainfall and temperature are the direct driving factors that affect grassland ecosystem evolution. The study constructed the assessment model of the driving factors, temperature and rainfall, that exerted influence on the primary productivities of the grassland ecosystems in headwater areas, and used the model to quantitatively analyze the primary productivity variations of the grassland ecosystems in the headwater areas with the temperature and rainfall from those in the baseline year on the basis of the nearly forty year climatic data collected by the meteorological stations of Qumalai County, Maduo County, Yushu County and Nangqian County. The results show that over the forty-one years between 1962 and 2002, the rainfall among the climate dominated natural factors was the critical factor that caused the primary productivities of the grassland ecosystems to vary in the headwater areas. Moreover, the temperature was the limiting factor of the primary productivities of the grassland ecosystems in the headwater areas, which gently affect the primary productivities of grassland ecosystems in the headwater areas.Key words: Climatic change, headwater, grassland, ecosystem, impact intensity
Integer quantum Hall effect and topological phase transitions in silicene
We numerically investigate the effects of disorder on the quantum Hall effect
(QHE) and the quantum phase transitions in silicene based on a lattice model.
It is shown that for a clean sample, silicene exhibits an unconventional QHE
near the band center, with plateaus developing at and
a conventional QHE near the band edges. In the presence of disorder, the Hall
plateaus can be destroyed through the float-up of extended levels toward the
band center, in which higher plateaus disappear first. However, the center
Hall plateau is more sensitive to disorder and disappears at a
relatively weak disorder strength. Moreover, the combination of an electric
field and the intrinsic spin-orbit interaction (SOI) can lead to quantum phase
transitions from a topological insulator to a band insulator at the charge
neutrality point (CNP), accompanied by additional quantum Hall conductivity
plateaus.Comment: 7 pages, 4 figure
Performance of Photosensors in the PandaX-I Experiment
We report the long term performance of the photosensors, 143 one-inch
R8520-406 and 37 three-inch R11410-MOD photomultipliers from Hamamatsu, in the
first phase of the PandaX dual-phase xenon dark matter experiment. This is the
first time that a significant number of R11410 photomultiplier tubes were
operated in liquid xenon for an extended period, providing important guidance
to the future large xenon-based dark matter experiments.Comment: v3 as accepted by JINST with modifications based on reviewers'
comment
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