9,999 research outputs found
Quantized Quasi-Two Dimensional Bose-Einstein Condensates with Spatially Modulated Nonlinearity
We investigate the localized nonlinear matter waves of the quasi-two
dimensional Bose-Einstein condensates with spatially modulated nonlinearity in
harmonic potential. It is shown that the whole Bose-Einstein condensates,
similar to the linear harmonic oscillator, can have an arbitrary number of
localized nonlinear matter waves with discrete energies, which are
mathematically exact orthogonal solutions of the Gross-Pitaevskii equation.
Their novel properties are determined by the principle quantum number n and
secondary quantum number l: the parity of the matter wave functions and the
corresponding energy levels depend only on n, and the numbers of density
packets for each quantum state depend on both n and l which describe the
topological properties of the atom packets. We also give an experimental
protocol to observe these novel phenomena in future experiments.Comment: 5 pages, 5 figure
Three-band tight-binding model for monolayers of group-VIB transition metal dichalcogenides
published_or_final_versio
Entanglement control in one-dimensional random XY spin chain
The entanglement in one-dimensional random XY spin systems where the
impurities of exchange couplings and the external magnetic fields are
considered as random variables is investigated by solving the different
spin-spin correlation functions and the average magnetization per spin. The
entanglement dynamics near particular locations of the system is also studied
when the exchange couplings (or the external magnetic fields) satisfy three
different distributions(the Gaussian distribution, double-Gaussian
distribution, and bimodal distribution). We find that the entanglement can be
controlled by varying the strength of external magnetic field and the different
distributions of impurities. Moreover, the entanglement of some
nearest-neighboring qubits can be increased for certain parameter values of the
three different distributions.Comment: 13 pages, 4 figure
An efficient compressive sensing based PS-DInSAR method for surface deformation estimation
Permanent scatterers differential interferometric synthetic aperture radar (PS-DInSAR) is a
technique for detecting surface micro-deformation, with an accuracy at the centimeter to millimeter
level. However, its performance is limited by the number of SAR images available (normally more than
20 are needed). Compressive Sensing (CS) has been proven to be an effective signal recovery method
with only a very limited number of measurements. Applying CS to PS-DInSAR, a novel
CS-PS-DInSAR method is proposed to estimate the deformation with fewer SAR images. By analyzing
the PS-DInSAR process in detail, first the sparsity representation of deformation velocity difference is
obtained; then, the mathematical model of CS-PS-DInSAR is derived and the restricted isometry
property (RIP) of the measurement matrix is discussed to validate the proposed CS-PS-DInSAR in
theory. The implementation of CS-PS-DInSAR is achieved by employing basis pursuit algorithms to
estimate the deformation velocity. With the proposed method, DInSAR deformation estimation can be
achieved by a much smaller number of SAR images, as demonstrated by simulation result
The entanglement in one-dimensional random XY spin chain with Dzyaloshinskii-Moriya interaction
The impurities of exchange couplings, external magnetic fields and
Dzyaloshinskii--Moriya (DM) interaction considered as Gaussian distribution,
the entanglement in one-dimensional random spin systems is investigated by
the method of solving the different spin-spin correlation functions and the
average magnetization per spin. The entanglement dynamics at central locations
of ferromagnetic and antiferromagnetic chains have been studied by varying the
three impurities and the strength of DM interaction. (i) For ferromagnetic spin
chain, the weak DM interaction can improve the amount of entanglement to a
large value, and the impurities have the opposite effect on the entanglement
below and above critical DM interaction. (ii) For antiferromagnetic spin chain,
DM interaction can enhance the entanglement to a steady value. Our results
imply that DM interaction strength, the impurity and exchange couplings (or
magnetic field) play competing roles in enhancing quantum entanglement.Comment: 12 pages, 3 figure
Quantized vortices in a rotating Bose-Einstein condensate with spatiotemporally modulated interaction
We present theoretical analysis and numerical studies of the quantized
vortices in a rotating Bose-Einstein condensate with spatiotemporally modulated
interaction in harmonic and anharmonic potentials, respectively. The exact
quantized vortex and giant vortex solutions are constructed explicitly by
similarity transformation. Their stability behavior has been examined by
numerical simulation, which shows that a new series of stable vortex states
(defined by radial and angular quantum numbers) can be supported by the
spatiotemporally modulated interaction in this system. We find that there exist
stable quantized vortices with large topological charges in repulsive
condensates with spatiotemporally modulated interaction. We also give an
experimental protocol to observe these vortex states in future experiments
Distances and classification of amino acids for different protein secondary structures
Window profiles of amino acids in protein sequences are taken as a
description of the amino acid environment. The relative entropy or
Kullback-Leibler distance derived from profiles is used as a measure of
dissimilarity for comparison of amino acids and secondary structure
conformations. Distance matrices of amino acid pairs at different conformations
are obtained, which display a non-negligible dependence of amino acid
similarity on conformations. Based on the conformation specific distances
clustering analysis for amino acids is conducted.Comment: 15 pages, 8 figure
Study on isolation of chemical constituents from Sophora Flavescens ait. And their anti-glioma effects
Background: Sophora flavescens Ait. is a traditional Chinese medicine with a long history in China. It is mainly used in the treatment of heat dysentery and similar ailments in the clinical. The objective of this paper was to isolate, purify and identify alkaloids from Sophora flavescens Ait. and to explore their inhibitory effects on C6 glioma cells.Materials and Methods: Column chromatography, extraction and NMR spectroscopy were used to structurally identify the isolated compounds. MTT assay and flow cytometry were used to detect the inhibitory effect of matrine on C6 cells.Results: Three compounds were isolated from Sophora flavescens Ait., namely matrine, oxymatrine and lupeol. Different concentrations of matrine solution all had inhibitory effects on growth of C6 cell lines, which showed apparent dose-effect relationship. Compared with the control group, proportion of G0/G1 phase cells increased in each matrine concentration group to a maximum of 79.8%; proportion of S phase cells reduced, and proportion of G2/M phase cells declined slightly to a minimum of 6.3%, suggesting that after the action of matrine proliferation of C6 cells was significantly inhibited and the cells were arrested in the G1 phase.Conclusion: We concluded that Sophora flavescens Ait. has an inhibitory effect on C6 cell proliferation.Keywords: Sophora flavescens Ait.; oxymatrine; lupeol; C6 glioma cell
Energy-related CO2 emission accounts and datasets for 40 emerging economies in 2010-2019
Since 2000, CO2 emissions from emerging economies have outstripped those of developed economies. To limit global warming to under 1.5gg C by 2100, over 100 emerging economies have proposed net-zero carbon targets. Yet the supportive data are lacking-no inventory of CO2 emission outlines detailed sources by sector or distribution at the subnational level for these economies. Here, we redress the balance by establishing a dataset for an energy-related CO2 emission inventory that covers 47 sectors and eight energy types in 40 emerging economies (10.5281/zenodo.7309360, Cui et al., 2021). Their emissions, growing rapidly by 3.0g%gyr-1, reached 7.5gGt in 2019 and were sourced primarily in coal and oil (34.6g% and 28.1g%, respectively) and consumed by the power and transportation sectors. Meanwhile, among African countries in this group, biomass combustion was responsible for 34.7g%-96.2g% of emissions. Our dataset fills a data gap by providing a detailed, robust emission accounting baseline for emerging economies-an advance that will support emission reduction policymaking at global, national, and subnational levels
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