110 research outputs found
SCAN-MUSIC: An Efficient Super-resolution Algorithm for Single Snapshot Wide-band Line Spectral Estimation
We propose an efficient algorithm for reconstructing one-dimensional
wide-band line spectra from their Fourier data in a bounded interval
. While traditional subspace methods such as MUSIC achieve
super-resolution for closely separated line spectra, their computational cost
is high, particularly for wide-band line spectra. To address this issue, we
proposed a scalable algorithm termed SCAN-MUSIC that scans the spectral domain
using a fixed Gaussian window and then reconstructs the line spectra falling
into the window at each time. For line spectra with cluster structure, we
further refine the proposed algorithm using the annihilating filter technique.
Both algorithms can significantly reduce the computational complexity of the
standard MUSIC algorithm with a moderate loss of resolution. Moreover, in terms
of speed, their performance is comparable to the state-of-the-art algorithms,
while being more reliable for reconstructing line spectra with cluster
structure. The algorithms are supplemented with theoretical analyses of error
estimates, sampling complexity, computational complexity, and computational
limit
Type-II Ising Pairing in Few-Layer Stanene
Spin-orbit coupling has proven indispensable in realizing topological
materials and more recently Ising pairing in two-dimensional superconductors.
This pairing mechanism relies on inversion symmetry breaking and sustains
anomalously large in-plane polarizing magnetic fields whose upper limit is
expected to diverge at low temperatures, although experimental demonstration of
this has remained elusive due to the required fields. In this work, the
recently discovered superconductor few-layer stanene, i.e. epitaxially strained
-Sn, is shown to exhibit a new type of Ising pairing between carriers
residing in bands with different orbital indices near the -point. The
bands are split as a result of spin-orbit locking without the participation of
inversion symmetry breaking. The in-plane upper critical field is strongly
enhanced at ultra-low temperature and reveals the sought for upturn
Intrinsic and tunable quantum anomalous Hall effect and magnetic topological phases in XYBi2Te5
By first-principles calculations, we study the magnetic and topological
properties of XYBi2Te5-family (X, Y = Mn, Ni, V, Eu) compounds. The strongly
coupled double magnetic atom-layers can significantly enhance the magnetic
ordering temperature while keeping the topologically nontrivial properties.
Particularly, NiVBi2Te5 is found to be a magnetic Weyl semimetal in bulk and a
Chern insulator in thin film with both the Curie temperature (~150 K) and full
gap well above 77 K. Ni2Bi2Te5, MnNiBi2Te5, NiVBi2Te5 and NiEuBi2Te5 exhibits
intrinsic dynamic axion state. Among them, MnNiBi2Te5 has a Neel temperature
over 200 K and Ni2Bi2Te5 even demonstrates antiferromagnetic order above room
temperature. These results indicate an approach to realize high temperature
quantum anomalous Hall effect and other topological quantum effects for
practical applications
Type-II Ising pairing in few-layer stanene
Spin-orbit coupling has proven indispensable in the realization of topological materials and, more recently, Ising pairing in two-dimensional superconductors. This pairing mechanism relies on inversion symmetry–breaking and sustains anomalously large in-plane polarizing magnetic fields whose upper limit is predicted to diverge at low temperatures. Here, we show that the recently discovered superconductor few-layer stanene, epitaxially strained gray tin (α-Sn), exhibits a distinct type of Ising pairing between carriers residing in bands with different orbital indices near the Γ-point. The bands are split as a result of spin-orbit locking without the participation of inversion symmetry–breaking. The in-plane upper critical field is strongly enhanced at ultralow temperature and reveals the predicted upturn
High-density lipoprotein cholesterol level as an independent protective factor against aggravation of acute pancreatitis: a case–control study
Background and aimsAt present, evidence on the association between high-density lipoprotein cholesterol (HDL-C) levels and aggravation of acute pancreatitis (AP) is limited. This study aimed to investigate the relationship between the lowest HDL-C level during intensive care units (ICU) stay and AP aggravation and to determine the optimum cutoff lowest HDL-C level.MethodsPatients admitted to the ICU of the Shandong Provincial Hospital for AP from 2015 to 2021 were included. The lowest HDL-C level during ICU stay was set as the independent variable, and the progression or non-progression to severe AP (SAP) was set as the dependent variable. Univariate and multivariate analyses were performed to determine the relationship between the two variables, and receiver operating characteristic (ROC) curves were plotted to analyze the predictive ability of the lowest HDL-C level for progression to SAP.ResultsThis study included 115 patients. The difference in the lowest HDL-C level between the SAP and moderately SAP groups was significant (P < 0.05). After adjusting for covariates, the lowest HDL-C level showed a negative correlation with the occurrence of SAP, with a relative risk of 0.897 (95% confidence interval: 0.827–0.973). The area under the ROC curve for prediction of AP aggravation by the lowest HDL-C level was 0.707, and the optimum cutoff lowest HDL-C level was 0.545 mmol/L.ConclusionNo less than 0.545 mmol/L of the HDL-C level during ICU stay may be an independent protective factor for the aggravation of AP
- …