83 research outputs found

    Film formation and surface renewal on a rotating spoked disk for polymer devolatilization

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    The financial supports from the National Natural Science Foundation of China (No.21676007) are gratefully acknowledged.Peer reviewedPostprin

    UAV hyperspectral analysis of secondary salinization in arid oasis cotton fields: effects of FOD feature selection and SOA-RF

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    Secondary salinization is a crucial constraint on agricultural progress in arid regions. The specific mulching irrigation technique not only exacerbates secondary salinization but also complicates field-scale soil salinity monitoring. UAV hyperspectral remote sensing offers a monitoring method that is high-precision, high-efficiency, and short-cycle. In this study, UAV hyperspectral images were used to derive one-dimensional, textural, and three-dimensional feature variables using Competitive adaptive reweighted sampling (CARS), Gray-Level Co-occurrence Matrix (GLCM), Boruta Feature Selection (Boruta), and Brightness-Color-Index (BCI) with Fractional-order differentiation (FOD) processing. Additionally, three modeling strategies were developed (Strategy 1 involves constructing the model solely with the 20 single-band variable inputs screened by the CARS algorithm. In Strategy 2, 25 texture features augment Strategy 1, resulting in 45 feature variables for model construction. Strategy 3, building upon Strategy 2, incorporates six triple-band indices, totaling 51 variables used in the model’s construction) and integrated with the Seagull Optimization Algorithm for Random Forest (SOA-RF) models to predict soil electrical conductivity (EC) and delineate spatial distribution. The results demonstrated that fractional order differentiation highlights spectral features in noisy spectra, and different orders of differentiation reveal different hidden information. The correlation between soil EC and spectra varies with the order. 1.9th order differentiation is proved to be the best order for constructing one-dimensional indices; although the addition of texture features slightly improves the accuracy of the model, the integration of the three-waveband indices significantly improves the accuracy of the estimation, with an R2 of 0.9476. In contrast to the conventional RF model, the SOA-RF algorithm optimizes its parameters thereby significantly improving the accuracy and model stability. The optimal soil salinity prediction model proposed in this study can accurately, non-invasively and rapidly identify excessive salt accumulation in drip irrigation under membrane. It is of great significance to improve the growing conditions of cotton, increase the cotton yield, and promote the sustainable development of Xinjiang’s agricultural economy, and also provides a reference for the prevention and control of regional soil salinization

    An intelligent analysis method of security and stability control strategy based on the knowledge graph

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    The security and stability control system is the guarantee of the security and stability operation of the power grid. With the increasing scale of distributed new energy access to the power grid, the security and stability control strategy of the power grid is becoming more complex, and it is becoming increasingly important to correctly analyze and implement the security and stability control strategy. In order to ensure the correctness of the security and stability control strategy implemented by the security and stability control device, it is necessary to analyze the security and stability control strategy in detail. Therefore, this article proposes an intelligent analysis method of the security and stability control strategy based on the knowledge graph. First, this article introduces the ontology design method of the security and stability control strategy based on the knowledge graph, combines the characteristics and applications of the knowledge graph, analyzes the relationship between the elements of the strategy, and designs a clear-structured knowledge network. Second, this article analyzes the automatic construction technology of the graph, constructs the six-element ontology model of the security and stability control strategy, and realizes the human–computer interaction functions such as auxiliary decision making, strategy reasoning, and intelligent search based on the knowledge graph. Using artificial intelligence technology, this article takes the security and stability control strategy of a certain area’s security and stability control system as an example to model and manage. The results show that it can assist the tester to quickly retrieve the strategy, effectively improve the detection efficiency of the security and stability control strategy, avoid the omission and ambiguity caused by the manual understanding of the strategy, and ensure the accuracy and comprehensiveness of the security and stability control strategy detection

    Meta-analysis of the association between dietary inflammatory index and cognitive health

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    BackgroundSome studies have shown that a pro-inflammatory diet may be associated with cognitive function, but their conclusions have varied considerably. We here present a meta-analysis of the current published literature on DII score and its association with cognitive health.MethodsIn this meta-analysis, the PubMed, Embase, Web of Science, and Cochrane databases were searched in September 2022. The reported indexes, specifically OR, RR, and β, were extracted and analyzed using R version 3.1.0.ResultsA total of 636 studies in databases were identified, and 12 were included in the meta-analysis. Higher DII was associated with an increased risk of AD and MCI (OR = 1.34; 95% CI = 1.21–1.49). Meanwhile, it may also cause global function impairment (categorical: OR = 1.63; 95% CI = 1.36–1.96) and verbal fluency impairment (continuous: OR = 0.18; 95% IC = 0.08–0.42). But there was no significant association between DII and executive function (categorical: OR = 1.12; 95% IC = 0.84–1.49; continuous: OR = 0.48; 95% IC = 0.19–1.21) or episodic memory (continuous: OR = 0.56; 95% IC = 0.30–1.03).ConclusionA pro-inflammatory diet is related to AD, MCI, and the functions of some cognitive domains (specifically global function and verbal fluency). However, the current evidence on the role of diet-induced inflammation in different cognitive domains should be supported by further studies in the future

    A New Look at the Scalar Meson f0(500)f_0(500) via D+π+π+νD^+\to \pi^+\pi^-\ell^+\nu_\ell Decays

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    Using 2.93 fb12.93~\mathrm{fb}^{-1} of e+ee^+e^- collision data collected with the BESIII detector at the center-of-mass energy of 3.773 GeV, we investigate the semileptonic decays D+π+π+νD^+\to \pi^+\pi^- \ell^+\nu_\ell (=e\ell=e and μ\mu). The D+f0(500)μ+νμD^+\to f_0(500)\mu^+\nu_\mu decay is observed for the first time. By analyzing simultaneously the differential decay rates of D+f0(500)μ+νμD^+\to f_0(500) \mu^+\nu_\mu and D+f0(500)e+νeD^+\to f_0(500) e^+\nu_e in different +ν\ell^+\nu_\ell four-momentum transfer intervals, the product of the relevant hadronic form factor f+f0(0)f^{f_0}_{+}(0) and the magnitude of the cdc\to d Cabibbo-Kobayashi-Maskawa matrix element Vcd|V_{cd}| is determined to be f+f0(0)Vcd=0.0787±0.0060stat±0.0033systf_{+}^{f_0} (0)|V_{cd}|=0.0787\pm0.0060_{\rm stat}\pm0.0033_{\rm syst} for the first time. With the input of Vcd|V_{cd}| from the global fit in the standard model, we determine f+f0(0)=0.350±0.027stat±0.015systf_{+}^{f_0} (0)=0.350\pm0.027_{\rm stat}\pm0.015_{\rm syst}. The absolute branching fractions of D+f0(500)(π+π)μ+νμD^+\to f_0(500)_{(\pi^+\pi^-)}\mu^+\nu_\mu and D+ρ(π+π)0μ+νμD^+\to \rho^0_{(\pi^+\pi^-)} \mu^+\nu_\mu are determined as (0.72±0.13stat±0.10syst)×103(0.72\pm0.13_{\rm stat}\pm0.10_{\rm syst})\times10^{-3} and (1.64±0.13stat±0.11syst)×103(1.64\pm0.13_{\rm stat}\pm0.11_{\rm syst})\times 10^{-3}. Combining these results with those of previous BESIII measurements on their semielectronic counterparts from the same data sample, we test lepton flavor universality by measuring the branching fraction ratios BD+ρ0μ+νμ/BD+ρ0e+νe=0.88±0.10{\mathcal B}_{D^+\to \rho^0 \mu^+\nu_\mu}/{\mathcal B}_{D^+\to \rho^0 e^+\nu_e}=0.88\pm0.10 and BD+f0(500)μ+νμ/BD+f0(500)e+νe=1.14±0.28{\mathcal B}_{D^+\to f_0(500) \mu^+\nu_\mu}/{\mathcal B}_{D^+\to f_0(500) e^+\nu_e}=1.14\pm0.28, which are compatible with the standard model expectation.Comment: Supplemental Materials added in this versio

    The complete mitochondrial genome of Holothuria fuscocinerea (Jaeger,1833)

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    In this study, the complete mitochondrial genome of Holothuria fuscocinerea was sequenced on an Illumina platform and assembled using NovoPlasty v. 2.7.1. It was submitted to NCBI GenBank and is available with accession number MN542416. The genome was 15,827 bp in size and contains 22 tRNA genes, 12 protein-coding genes, and 2 rRNA genes. The composition of A + T in Holothura spinifera mtDNA was 60.30%. Except ND6 and 5 tRNAs, the others are not on the H-strand. The phylogenetic relationship of 13 species of sea cucumber were analyzed using the neighbor-joining method by software MEGA5.0. Holothuria fuscocinerea was most closely related to Holothuria polii

    Seismic Response Mitigation of a Long-Span Tower Bridge with Two Types of Constraint System

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    The stress of the main tower of a cable-stayed bridge depends on the connection type between the tower and deck. In order to study the most suitable longitudinal damping mode for a long-span cable-stayed bridge. In this article, a nonlinear finite element model is established based on a large span concrete cable-stayed bridge with a main span of 680 m. Without considering the influence of the transverse constraint, the damping effect of the elastic connection device and the viscous damper is simulated when the longitudinal seismic load is input. The results show that the stiffness of the main beam is increased by installing the elastic connection device, so the longitudinal drift frequency of the main beam is increased, but the stiffness of the structure is not changed by installing the viscous damper. Both viscous dampers and elastic connection structures can reduce the longitudinal displacement of the beam end, but viscous dampers are more favorable for the stress of the main tower. In terms of damping effect, viscous dampers are more suitable for long-span cable-stayed bridges, but, in terms of economy and parameter control, elastic connection devices have more advantages

    A Novel Dynamic Event-Triggered Mechanism for Distributed Secondary Control in Islanded AC Microgrids

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    In this paper, the frequency/voltage restoration and active power sharing problems of islanded AC microgrids are studied. A novel distributed dynamic event-triggered secondary control scheme is proposed to reduce the communication burden. The continuous monitoring of event-triggered conditions and Zeno behavior can be fundamentally avoided by periodically evaluating event-triggered conditions. In addition, by introducing an adaptive coefficient related to the system deviations, the control performance can be improved. Sufficient conditions to ensure the stability of the system are provided through a Lyapunov function. Lastly, the effectiveness of our proposed secondary control scheme is verified in a MATLAB/SimPowerSystems environment

    A Novel Dynamic Event-Triggered Mechanism for Distributed Secondary Control in Islanded AC Microgrids

    No full text
    In this paper, the frequency/voltage restoration and active power sharing problems of islanded AC microgrids are studied. A novel distributed dynamic event-triggered secondary control scheme is proposed to reduce the communication burden. The continuous monitoring of event-triggered conditions and Zeno behavior can be fundamentally avoided by periodically evaluating event-triggered conditions. In addition, by introducing an adaptive coefficient related to the system deviations, the control performance can be improved. Sufficient conditions to ensure the stability of the system are provided through a Lyapunov function. Lastly, the effectiveness of our proposed secondary control scheme is verified in a MATLAB/SimPowerSystems environment
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