13,788 research outputs found
Magnetic Soliton and Soliton Collisions of Spinor Bose-Einstein Condensates in an Optical Lattice
We study the magnetic soliton dynamics of spinor Bose-Einstein condensates in
an optical lattice which results in an effective Hamiltonian of anisotropic
pseudospin chain. A modified Landau-Lifshitz equation is derived and exact
magnetic soliton solutions are obtained analytically. Our results show that the
time-oscillation of the soliton size can be controlled in practical experiment
by adjusting of the light-induced dipole-dipole interaction. Moreover, the
elastic collision of two solitons is investigated.Comment: 16 pages, 5 figure
Strong Lensing Probabilities in a Cosmological Model with a Running Primordial Power Spectrum
The combination of the first-year Wilkinson Microwave Anisotropy Probe (WMAP)
data with other finer scale cosmic microwave background (CMB) experiments (CBI
and ACBAR) and two structure formation measurements (2dFGRS and Lyman
forest) suggest a CDM cosmological model with a running spectral power
index of primordial density fluctuations. Motivated by this new result on the
index of primordial power spectrum, we present the first study on the predicted
lensing probabilities of image separation in a spatially flat CDM
model with a running spectral index (RSI-CDM model). It is shown that
the RSI-CDM model suppress the predicted lensing probabilities on
small splitting angles of less than about 4 compared with that of
standard power-law CDM (PL-CDM) model.Comment: 11 pages including 1 figures. Accepted for publication in Modern
Physics Letters A (MPLA), minor revision
Critical transmission sectors in embodied atmospheric mercury emission network in China
Atmospheric mercury is a crucial pollutant that must be well-controlled to avoid damaging public health. It is thus necessary to understand from multiple perspectives the roles played by different industrial sectors, as well as their geographical distribution. Existing studies have overlooked the transmission sectors in the economic supply chains of the embodied atmospheric mercury emission network. In this paper, we offer a betweenness-based account (BBA) for Chinese regions and industrial sectors in transmitting embodied atmospheric mercury emissions and in doing so have identified the transmitting hubs. Our results show that the Henan province acts as the transmission hub of the embodied atmospheric mercury emission network in China. The metallurgy, chemical, and construction industries generally play important roles in the transmission of embodied atmospheric mercury emissions across China. Henan's metallurgy sector, the third highest of all, is more closely linked with inter-provincial sectors than the top two transmission sectors (the metallurgy industry of Jiangsu and the chemical industry of Shandong). This study can help policy makers improve mercury control measures by focusing on transmission processes for effective and comprehensive atmospheric mercury emission control
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Quantifying physical transport and local proliferation of phytoplankton downstream of an eutrophicated lake
Eutrophication in a freshwater system has mainly been studied in lakes and their upstream rivers, which are responsible to bring pollutants into the lakes. However, the influence of lakes on downstream rivers suffered massive algae from upstream lakes has not been fully studied. Our study area is Liangxi river, downstream of Taihu Lake, which is highly eutrophicated. The algae in Liangxi river has two origins: the physical transport from Taihu Lake and the in-situ proliferation. This paper aims to apply numerical model to quantify these two processes. The model is calibrated against the measured data in 2018. This computational condition that includes both algal processes is termed as Scheme A. Then, we regarded phytoplankton as a conservative substance by turning off the phytoplankton biological process and calculated term it as Scheme E. We selected the chl-a concentration in Hongqiao (LX2) section to represent the amount of algae in Liangxi river. The average chl-a difference in this section between Schemes A and E, Delta, can be used to quantify the magnitude of in-situ proliferation. The Delta varies seasonally, and the annual average is 7.22 mg/m³, which is 44.7% of the amount attributed to the physical transport. Liangxi river lies in an urban area which might encounter extreme events which to facilitate the in-situ proliferation, such as increased temperature and or excessive nutrient load. To quantify the level of algae under extreme situations, we design Schemes B, C and D which eliminated the limitation on algal growth by temperature, nitrogen and phosphorus respectively. Compared with the Scheme A, Schemes B, C and D oberve 21.8%, 65.7%and 61.2% respectively, increase in the average algal concentration. In the vertical direction, the chl-a concentration varies between 0.8mg/m³ and 2 mg/m³ in Scheme A, while the vertical concentration variances of chl-a in schemes B, C and D are found to be 5.56 mg/m³, 12.11 mg/m³ and 3.30 mg/m³, respectively.National Natural Science Foundation of China (No.51779075); Priority Academic Program Development of Jiangsu Higher Education Institutions; Major Science and Technology Program for Water Pollution Control and Treatment of China (2017ZX07203002-01)
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