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The loss of excitation fault of large condenser seriously affects the safety and stability of equipment and system. The reliability and selectivity of existing low-voltage and reactive power reverse criteria based on local static threshold are insufficient. In this paper, a loss of excitation protection principle based on intelligent identification of the global dynamic trajectory of the measured impedance is proposed, which can reflect the operating state of the condenser. From the point of view of kinematics, characteristic quantity time series that can accurately restore the measured impedance trajectory under loss of excitation and other conditions is formed, and statistics is further introduced to extract the highly explanatory features. Multiple kernel learning support vector machine (MKL-SVM) is trained by using the combination of global and local kernel functions of adaptive weights to ensure the learning ability of the classification model while enhancing its generalization ability. A two-stage recognition strategy based on the space distance of the classification core is proposed, which can improve the protection reliability while ensuring the system security. The model of condenser connected to power grid is built based on PSCAD simulation platform for verification, and simulation results show that the proposed method does not need to collect the electrical quantities at the rotor side with high identification accuracy, and it still has excellent applicability in the face of new energy access and unknown disturbances.

Portulaca oleracea is widely distributed around the world and has a long history of dual use in the fields of medicine and food. Its chemical constituents include flavonoids, polyphenols, terpenoids, sterols, coumarins, alkaloids, polysaccharides and organic acids, which make it have excellent antibacterial and antioxidant effects. More and more research has reported the antibacterial activity of Portulaca oleracea, which is significantly different on different bacteria, but a systematic review is lacking. In this paper, we summarize recent progress in research on the chemical composition, antimicrobial effect and mechanism of Portulaca oleracea in order to provide as a reference for the bioefficacy research, clinical application and product development of Portulaca oleracea.

With the increase of software tools used in the airborne software development and verification process to meet DO-178C, in order to ensure its airworthiness and safety, DO-330 is taken as a guide for software tool qualification process of DO-178C. At present, the commercial off-the-shelf (COTS) tools cannot meet the requirements of specific project development and verification. The evaluation tool qualification level, life cycle process and objective of tool qualification in DO-330 are used as the guidance basis. The main concerns and difficulties in the process of DO-330 engineering practice are analyzed. Combined with the actual project, the qualification process of self-developed tool to meet the requirements of DO-330 is given. The results show that the self-developed tool qualification of tool qualification level 5 (TQL-5) proposed in this paper has engineering feasibility, and has made substantial progress, which provides reference and guidance to meet specific project requirements and perform software tool qualification according to DO-330 requirements.

Purpose: To propose an efficient collimator angle optimization method by combining island blocking (IB) and parked gap (PG) problem to reduce the radiotherapy dose for normal tissue. The reduction will be done with single‐isocenter multi‐lesion volumetric modulated arc therapy (VMAT) for the stereotactic body radiation therapy (SBRT) of liver cancer. Methods: A novel collimator angle optimization algorithm was developed based on the two‐dimensional projection of targets on a beam's eye view (BEV) plane as a function of gantry and collimator angle. This optimization algorithm minimized the sum of the combined IB and PG (IB & PG) areas from all gantry angles for each arc. For comparison, two SBRT plans were respectively generated for each of the 20 retrospective liver cancer cases with multiple lesions. One plan was optimized using the IB & PG algorithm, and the other plan was optimized with a previously reported optimization algorithm that only considered the IB area. Plans were then evaluated and compared using typical dosimetric metrics. Results: With the comparable target coverage, IB & PG plans had significantly lower D500cc, D700cc, mean dose (Dmean), and V15 of normal liver tissues when compared to IB plans. The median percent reductions were 3.32% to 5.36%. The D1cc, D5cc, and Dmean for duodenum and small intestine in IB & PG plans were significantly reduced in a range from 7.60% up to 16.03%. Similarly, the median integral dose was reduced by 3.73%. Furthermore, the percentage of normal liver Dmean sparing when IB & PG plans compared to IB plans, was found to be positively correlated (ρ = 0.669, P = 0.001) with the inter‐target distance. Conclusion: The proposed IB & PG algorithm has been demonstrated to outperform the IB algorithm in almost all normal tissue sparing, and the magnitude of liver sparing was positively correlated with inter‐target distance. [ABSTRACT FROM AUTHOR]

To reduce the current harmonics on the input side of a multi-pulse rectifier, this paper proposes a low harmonic current source series multi-pulse rectifier based on an auxiliary passive injection circuit at the DC side. The rectifier only needs to add an auxiliary passive injection circuit on the DC side of the series 12-pulse rectifier, which can change its AC input voltage from 12-step waves to 24-step waves. We analyzed the working mode of the rectifier, optimized the optimal turn ratio of the injection transformer from the perspective of minimizing the total harmonic distortion (THD) value of the input voltage on the AC side, and analyzed the diode open circuit fault in the auxiliary passive injection circuit. Test verification shows that, after using the passive harmonic injection circuit, the THD value of the input voltage of the AC side of the rectifier is reduced from 14.03% to 4.86%. The THD value of the input current is reduced from 5.30% to 2.16%. The input power factor has been increased from 98.86% to 99.83%, and the power quality has been improved. [ABSTRACT FROM AUTHOR]

Background: Systemic Lupus Erythematosus (SLE), a prototypical autoimmune disorder, presents a challenge due to the absence of reliable biomarkers for discerning organ-specific damage within SLE. A growing body of evidence underscores the pivotal involvement of N6-methyladenosine (m6A) in the etiology of autoimmune conditions.Methods: The datasets, which primarily encompassed the expression profiles of m6A regulatory genes, were retrieved from the Gene Expression Omnibus (GEO) repository. The optimal model, selected from either Random Forest (RF) or Support Vector Machine (SVM), was employed for the development of a predictive nomogram model. To identify pivotal genes associated with SLE, a comprehensive screening process was conducted utilizing LASSO, SVM-RFE, and RF techniques. Within the realm of SLE susceptibility, Weighted Gene Co-expression Network Analysis (WGCNA) was harnessed to delineate relevant modules and hub genes. Additionally, MeRIP-qPCR assays were performed to elucidate key genes correlated with m6A targets. Furthermore, a Mendelian randomization study was conducted based on genome-wide association studies to assess the causative influence of MMP9 on ischemic stroke (IS), which is not only a severe cerebrovascular event but also a common complication of SLE.Results: Twelve m6A regulatory genes was identified, demonstrating statistical significance (p < 0.05) and utilized for constructing a nomogram model using the RF algorithm. EPSTI1, USP18, HP, and MMP9, as the hub genes, were identified. MMP9 uniquely correlates with m6A modification and was causally linked to an increased risk of IS, as indicated by our inverse variance weighting analysis showing an odds ratio of 1.0134 (95% CI=1.0004– 1.0266, p = 0.0440).Conclusion: Our study identified twelve m6A regulators, shedding light on the molecular mechanisms underlying SLE risk genes. Importantly, our analysis established a causal relationship between MMP9, a key m6A-related gene, and ischemic stroke, a common complication of SLE, thereby providing critical insights for presymptomatic diagnostic approaches. [ABSTRACT FROM AUTHOR]

Significant amounts of nitrogen and phosphorus in sediments will be released into the overlying water during the flood season in the water level fluctuation zone (WLFZ) of reservoirs that undergo periodic drying and flooding. This will result in water quality deterioration of the reservoir. In order to clarify the distribution characteristics and release behavior of nitrogen (N) and phosphorus (P) from sediments in the WLFZ of a reservoir, this study analyzed the sediment distribution characteristics and potential exchange flux sediment–water interface(SWI) through field investigations and sediment core incubation experiments. And the main factors affecting the release of N and P through the incubation experiments in sediments of the WLFZ in the reservoir were determined. Our findings indicated that the sediment in the WLFZ serves as the primary source of NH4+-N and acts as a sink for NO2-N in the overlying water of sediment. The concentration of NH4+-N in the interstitial water of sediments is the key factor that affects the water quality of Biliuhe Reservoir. Total nitrogen content of surface sediments in the WLFZ of Biliuhe Reservoir ranges from 1052.52 ± 49.39 to 3520.54 ± 30.31 mg/kg. High concentrations of N pollution are the primary increased risk of eutrophication in Biliuhe Reservoir during summer. The sediment N and P release flux of BLH1 located in the main stream is 1.67 ± 1.06 and 12.32 ± 2.42 mg·(m2·d)−1, respectively, which is smaller than that of BLH2 (3.27 ± 2.15 and 15.19 ± 2.36 mg·(m2·d)−1, respectively), BLH3 (4.24 ± 1.74 and 17.02 ± 2.47 mg·(m2·d)−1, respectively) and BLH4 (7.78 ± 2.03 and 20.56 ± 2.38 mg·(m2·d)−1, respectively) located in the tributary. It indicates that the water conveyance project located in BLH1 has an impact on nutrient scouring of sediments in the WLFZ at this site. The main water environment factor affecting the release of N and P in the sediment of the WLFZ is dissolved oxygen (DO). And the Pearson correlation coefficients between TN and TP with DO were −0.838 and −0.777, respectively (p < 0.05). At the same time, the diffusion of nutrients in the sediments can be effectively inhibited by maintaining a certain DO concentration in the overlying water. [ABSTRACT FROM AUTHOR]