577 research outputs found
Research progress on the relationship between white matter hyperintensity and cognitive impairment
White matter hyperintensity (WMH) is one of the imaging markers of cerebral small vessel disease (CSVD). Recent studies have found certain relationship between WMH and cognitive impairment. In this article,the mechanism of WMH formation,the relationship between WMH and cognitive impairment,the mechanism of cognitive dysfunction caused by WMH were reviewed,aiming to deepen the understanding of the relationship between WMH and cognitive impairment
A novel method of interference source direction-finding with an existing single antenna beam in communication satellites
Interference has recently become a critical factor in communication satellite performance, and the interference source location is one of the most important factors in resolving this issue. The article proposes an innovative method of interference source direction-finding suitable for communication satellites with an existing single antenna beam and single radio frequency (RF) channel, which utilizes the symmetry of the antenna pattern to search for interference sources. Compared to traditional position methods with time-frequency-synchronized multi-satellites or a directing antenna array in a single satellite, the method does not require any particular direction-finding payload in communication satellites and shares existing antennas and RF channels with communication systems in satellites. The ability to find the direction of the interference source is a software-defined function in the communication processor. The proposed method provides a novel way to solve the problems of interference source direction-finding with the least engineering complexity, and it has excellent coexistence with other existing systems in communication satellites. The computer simulation and out-field experiment results in this article show that the method has excellent performance with high direction-finding resolution within extensive coverage, offering significant value and bright prospects for resolving the growing interference issues in communication satellites
Emergence of scale-free close-knit friendship structure in online social networks
Despite the structural properties of online social networks have attracted
much attention, the properties of the close-knit friendship structures remain
an important question. Here, we mainly focus on how these mesoscale structures
are affected by the local and global structural properties. Analyzing the data
of four large-scale online social networks reveals several common structural
properties. It is found that not only the local structures given by the
indegree, outdegree, and reciprocal degree distributions follow a similar
scaling behavior, the mesoscale structures represented by the distributions of
close-knit friendship structures also exhibit a similar scaling law. The degree
correlation is very weak over a wide range of the degrees. We propose a simple
directed network model that captures the observed properties. The model
incorporates two mechanisms: reciprocation and preferential attachment. Through
rate equation analysis of our model, the local-scale and mesoscale structural
properties are derived. In the local-scale, the same scaling behavior of
indegree and outdegree distributions stems from indegree and outdegree of nodes
both growing as the same function of the introduction time, and the reciprocal
degree distribution also shows the same power-law due to the linear
relationship between the reciprocal degree and in/outdegree of nodes. In the
mesoscale, the distributions of four closed triples representing close-knit
friendship structures are found to exhibit identical power-laws, a behavior
attributed to the negligible degree correlations. Intriguingly, all the
power-law exponents of the distributions in the local-scale and mesoscale
depend only on one global parameter -- the mean in/outdegree, while both the
mean in/outdegree and the reciprocity together determine the ratio of the
reciprocal degree of a node to its in/outdegree.Comment: 48 pages, 34 figure
Emergent Schr\"{o}dinger cat states during superradiant phase transitions
Superradiant phase transitions (SPTs) are important for understanding
light-matter interactions at the quantum level [1, 2], and play a central role
in criticality-enhanced quantum sensing [3]. So far, SPTs have been observed in
driven-dissipative systems [4-9], but the emergent light fields did not show
any nonclassical characteristic due to the presence of strong dissipation. Here
we report an experimental demonstration of the SPT featuring the emergence of a
highly nonclassical photonic field, realized with a resonator coupled to a
superconducting qubit, implementing the quantum Rabi model [10, 11]. We fully
characterize the light-matter state by Wigner matrix tomography. The measured
matrix elements exhibit quantum interference intrinsic of a photonic
Schr\"{o}dinger cat state [12], and reveal light-matter entanglement. Besides
their fundamental importance, these hitherto unobserved emergent quantum
phenomena are useful for quantum metrology and fault-tolerant quantum
computation.Comment: 19 pages, 14 figures, 2 table
A predictive energy management strategy for multi-mode plug-in hybrid electric vehicles based on multi neural networks
Online optimal energy management of plug-in hybrid electric vehicles has been continually investigated for better fuel economy. This paper proposed a predictive energy management strategy based on multi neural networks for a multi-mode plug-in hybrid electric vehicle. To attain it, firstly, the offline optimal results prepared for knowledge learning are derived by dynamic programming and Pontryagin’s minimum principle. Then, the mode recognition neural network is trained based on the optimal results of dynamic programming and the recurrent neural network is firstly exploited to realize online co-state estimation application. Consequently, the velocity prediction-based online model predictive control framework is established with the co-state correction and slacked constraints to solve the real-time optimal control sequence. A series of numerical simulation results validate that the optimal performance yielded from global optimal strategy can be exploited online to attain the satisfied cost reduction, compared with equivalent consumption minimum strategy, with the assistance of estimated real time co-state and slacked reference. In addition, the computation duration of proposed algorithm decreases by 23.40%, compared with conventional Pontryagin’s minimum principle-based model predictive control scheme, thereby proving its online application potential
Erratum to: Binding Energy and Spin-Orbit Splitting of a Hydrogenic Donor Impurity in AlGaN/GaN Triangle-Shaped Potential Quantum Well
In the framework of effective-mass envelope function theory, including the effect of Rashba spin-orbit coupling, the binding energyEband spin-orbit split energy Г of the ground state of a hydrogenic donor impurity in AlGaN/GaN triangle-shaped potential heterointerface are calculated. We find that with the electric field of the heterojunction increasing, (1) the effective width of quantum well decreases and (2) the binding energy increases monotonously, and in the mean time, (3) the spin-orbit split energy Г decreases drastically. (4) The maximum of Г is 1.22 meV when the electric field of heterointerface is 1 MV/cm
In Vitro Antioxidant Activities of Sulfated Derivatives of Polysaccharides Extracted from Auricularia auricular
In this research, two types of sulfated polysaccharide derivatives were successfully synthesized. Their antioxidant activities were investigated by employing various established in vitro systems. In addition, the degree of sulfation was evaluated using ion-chromatography and IR spectra. The results verify that, when employing scavenging superoxide radical tests, both the sulfation of acid Auricularia auricular polysaccharides (SAAAP) and the sulfation of neutral Auricularia auricular polysaccharides (SNAAP) derivatives possessed considerable antioxidant activity and had a more powerful antioxidant competence than that of the native non-sulfated polysaccharides (AAAP and NAAP). On the other hand, AAAP and NAAP exhibited stronger activity on scavenging both the hydroxyl radical and lipid peroxidation. Available data obtained with in vitro measurements indicates that the sulfated groups of AAAP and NAAP played an important role on antioxidant activity. In sum, the research demonstrates that the antioxidant activity of sulfated polysaccharide derivatives in vitro has a potential significance for seeking new natural antioxidant protective agents
Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay
The decay channel
is studied using a sample of events collected
by the BESIII experiment at BEPCII. A strong enhancement at threshold is
observed in the invariant mass spectrum. The enhancement can be fit
with an -wave Breit-Wigner resonance function with a resulting peak mass of
and a
narrow width that is at the 90% confidence level.
These results are consistent with published BESII results. These mass and width
values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics
Skywork: A More Open Bilingual Foundation Model
In this technical report, we present Skywork-13B, a family of large language
models (LLMs) trained on a corpus of over 3.2 trillion tokens drawn from both
English and Chinese texts. This bilingual foundation model is the most
extensively trained and openly published LLMs of comparable size to date. We
introduce a two-stage training methodology using a segmented corpus, targeting
general purpose training and then domain-specific enhancement training,
respectively. We show that our model not only excels on popular benchmarks, but
also achieves \emph{state of the art} performance in Chinese language modeling
on diverse domains. Furthermore, we propose a novel leakage detection method,
demonstrating that test data contamination is a pressing issue warranting
further investigation by the LLM community. To spur future research, we release
Skywork-13B along with checkpoints obtained during intermediate stages of the
training process. We are also releasing part of our SkyPile corpus, a
collection of over 150 billion tokens of web text, which is the largest high
quality open Chinese pre-training corpus to date. We hope Skywork-13B and our
open corpus will serve as a valuable open-source resource to democratize access
to high-quality LLMs
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