34 research outputs found

    Multiscale reconstruction of porous media based on multiple dictionaries learning

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    Digital modeling of the microstructure is important for studying the physical and transport properties of porous media. Multiscale modeling for porous media can accurately characterize macro-pores and micro-pores in a large-FoV (field of view) high-resolution three-dimensional pore structure model. This paper proposes a multiscale reconstruction algorithm based on multiple dictionaries learning, in which edge patterns and micro-pore patterns from homology high-resolution pore structure are introduced into low-resolution pore structure to build a fine multiscale pore structure model. The qualitative and quantitative comparisons of the experimental results show that the results of multiscale reconstruction are similar to the real high-resolution pore structure in terms of complex pore geometry and pore surface morphology. The geometric, topological and permeability properties of multiscale reconstruction results are almost identical to those of the real high-resolution pore structures. The experiments also demonstrate the proposal algorithm is capable of multiscale reconstruction without regard to the size of the input. This work provides an effective method for fine multiscale modeling of porous media

    A phytophthora effector manipulates host histone acetylation and reprograms defense gene expression to promote infection

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    Immune response during pathogen infection requires extensive transcription reprogramming. A fundamental mechanism of transcriptional regulation is histone acetylation. However, how pathogens interfere with this process to promote disease remains largely unknown. Here we demonstrate that the cytoplasmic effector PsAvh23 produced by the soybean pathogen Phytophthora sojae acts as a modulator of histone acetyltransferase (HAT) in plants. PsAvh23 binds to the ADA2 subunit of the HAT complex SAGA and disrupts its assembly by interfering with the association of ADA2 with the catalytic subunit GCN5. As such, PsAvh23 suppresses H3K9 acetylation mediated by the ADA2/GCN5 module and increases plant susceptibility. Expression of PsAvh23 or silencing of GmADA2/GmGCN5 resulted in misregulation of defense-related genes, most likely due to decreased H3K9 acetylation levels at the corresponding loci. This study highlights an effective counter-defense mechanism by which a pathogen effector suppresses the activation of defense genes by interfering with the function of the HAT complex during infection

    Optimization of the lightning warning model for distribution network lines based on multiple meteorological factor thresholds

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    Lightning is one of the frequent natural disasters, which seriously affects the secure and stable operation of the power system, especially the distribution network lines with weak reliability. In order to improve the power supply reliability of the distribution network, higher requirements are put forward for the accuracy of lightning warning. Therefore, this paper establishes a lightning warning model based on comprehensive multi-meteorological factor thresholds and analyzes the meteorological factor data such as atmospheric field strength, echo intensity, echo-top height, and vertical cumulative liquid water content under thunderstorm weather. The threshold value of each factor warning is obtained, and the corresponding threshold weight is calculated by the entropy weight method. According to the weight of each threshold, the comprehensive threshold index of lightning warning is obtained, and the lightning warning is based on this index. A total of 105 lightning data from May to June 2022 in Nanchang city were analyzed as samples. The thresholds of atmospheric field strength, echo intensity, echo-top height, and vertical cumulative liquid water content were 1.2 kV/m, 40 dBZ, 8 km, and 5.2 kg·m−2, respectively. The corresponding weights of each factor were 0.4188, 0.2056, 0.2105, and 0.165, respectively. This model was used to warn a thunderstorm event in July 2022 in Nanchang area. The success rate of the model warning was 0.91, the false alarm rate (FAR) was 0.11, and the critical success index (CSI) was 0.80. Compared with the single-factor threshold lightning warning model, the warning FAR is decreased by 6%, and CSI is increased by 14% while ensuring the high warning success rate

    Coupled single-port method based voltage stability assessment with inverter-based generators

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    With the increase of inverter-based generators in the power system, the proportion of traditional generators is decreasing, and their voltage support ability to the power system is weakening, the power system operation is approaching to its voltage stability limit. It is of great significance to study on-line analysis of power system voltage stability under different control manners of inverter-based generators. Firstly, impedance matching theory and coupled single-port circuit theory are introduced. Secondly, coupled single-port method based voltage stability assessment method with inverter-based generators is proposed. Then, use the impedance matching condition and proposed method to analyze the influence of inverter-based generators on voltage stability in different control manners. The proposed method can reveal the voltage stability margin of power system with inverter-based generators in the current running state, and is suitable as an on-line voltage stability approach to evaluate the proximity of voltage collapse in real time. The various scenario simulations experiment validate the effectiveness and accuracy of the proposed method. Meanwhile, experimental analysis results show that different control manners of inverter-based generators not only affect voltage stability margin but also change the weakest bus of power system

    Impacts of Building Energy Consumption Information on Energy-Saving Intention of College Students

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    As college students bear little energy cost of public buildings on campus, information intervention is more feasible than economic intervention to augment the energy-saving intention of college students. College students are sensitive to environmental information; thus, building energy consumption information, which reflects the energy consumption levels of the environment where students live, may be effective to promote the energy-saving intention of college students. However, the changeable cognitive structure of college students makes it difficult to predict the cognitive results of building energy consumption information. Based on social cognitive theory and theory of planned behavior, this paper reveals the impacts of building energy consumption information on energy-saving intentions of college students from the perspective of perceived value and personal norms. The conclusions are: (1) The impacts are positive and indirect; (2) the impacts are realized through the path “perceived benefit—perceived value—intention” and “perceived benefit & risk—personal norm—intention”; (3) the perceived value and personal norm independently affect energy-saving intention; and (4) the effect of perceived benefits is the most obvious. Based on the above results, we put forward a series of policy suggestions, with the aim to enhance the positive effect of building energy consumption information on college students

    Exploring risk factors for totally implantable venous access devices (TIVADs)-related thrombotic occlusion in the off-treatment period

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    Abstract Totally implantable venous access devices (TIVADs) have been widely used for many years in the management of patients suffering from cancer. Thrombotic occlusion is the most common functional complication in the off-treatment period. This study aims to investigate the incidence of and risk factors for TIVADs-related thrombotic occlusion in patients with breast cancer. The clinical data of 1586 eligible patients with breast cancer with TIVADs at the Fourth Affiliated Hospital of Hebei Medical University from 1 January 2019 to 31 August 2021 were analysed. Thrombotic occlusion was confirmed by angiography with signs of partial or total occlusion. Thrombotic occlusion occurred in 96 (6.1%) cases. Multivariable logistic regression analysis showed that the insertion site of the catheter (P = 0.004), size of the catheter (P < 0.001), and indwelling time (P < 0.001) were significant factors for thrombotic occlusion. Insertion in the right internal jugular vein, smaller catheter size and shorter indwelling time can lower the incidence of thrombotic occlusion in breast cancer patients with TIVADs in the off-treatment period
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