Partitioning Method of Virtual Microgrid Based on Electrical Coupling Strength

© 2019 Automation of Electric Power Systems Press. With the fast development in the research of smart grid and Energy Internet, more and more distributed renewable energy and energy storage devices are connected into distribution networks, intelligent development of distribution network has become an inevitable trend. It is a big challenge for large-scale conventional distribution networks to be consistent with the requirements of free, equal and flexible interaction. Virtual microgrids with high internal convergence are proposed based on electrical coupling strength, which is partitioned from conventional power distribution networks. Furthermore, an implementation framework of virtual microgrids based on extended cyber, physical and socioeconomic is put forward, three-stage research problems of boundary division, resource optimization deployment and collaborative capability management are introduced. According to the first problem, by defining the electrical coupling strength, the classical Newman fast partitioning algorithm is upgraded in complicated network to realize the automatic optimization of boundary in virtual microgrids. Through case studies, the proposed algorithm is verified to be reasonable and efficient

Partitioning Method of Virtual Microgrid Based on Electrical Coupling Strength

© 2019 Automation of Electric Power Systems Press. With the fast development in the research of smart grid and Energy Internet, more and more distributed renewable energy and energy storage devices are connected into distribution networks, intelligent development of distribution network has become an inevitable trend. It is a big challenge for large-scale conventional distribution networks to be consistent with the requirements of free, equal and flexible interaction. Virtual microgrids with high internal convergence are proposed based on electrical coupling strength, which is partitioned from conventional power distribution networks. Furthermore, an implementation framework of virtual microgrids based on extended cyber, physical and socioeconomic is put forward, three-stage research problems of boundary division, resource optimization deployment and collaborative capability management are introduced. According to the first problem, by defining the electrical coupling strength, the classical Newman fast partitioning algorithm is upgraded in complicated network to realize the automatic optimization of boundary in virtual microgrids. Through case studies, the proposed algorithm is verified to be reasonable and efficient

Determination of flavonoids and phenolic acids in the extract of bamboo leaves using near-infrared spectroscopy and multivariate calibration

The content of flavonoids and phenolic acids in the extract of bamboo leaves (EBL) was determined using near-infrared spectroscopy. Optimal partial least squares models and least squares-support vector machine models were developed to enable rapid and non-destructive validation based on EBL contents as determined by photocolorimetric methods and high performance liquid chromatography. The least squares-support vector machine models performed slightly better than the partial least squares models. For least squares-support vector machine models, the correlation coefficients (R) and root mean square errors (RMSE) of calibration and validation were R(cal)= 0.9998, RMSE(cal)= 0.05, R(val)= 0.9418 and RMSE(val)= 3.91 for total flavonoids (TF) and R(cal)= 0.9778, RMSE(cal)= 2.49, R(val)= 0.9535, and RMSE(val)= 3.61 for total phenolic acids (TP). For optimal partial least squares models, the corresponding values were 0.9962, 1.12, 0.9124 and 4.97 for TF and 0.9966, 0.98, 0.9325 and 4.33 for TP. The results indicated that near-infrared spectroscopy with least squares-support vector machine could be utilized as a precise method for the determination of flavonoids and phenolic acids in EBL.Key words: Near-infrared spectroscopy, extract of bamboo leaves (EBL), flavonoids, phenolic acids, partial least squares models, least squares-support vector machine models

Enhanced apoptosis and senescence of bone-marrow-derived mesenchymal stem cells in patients with systemic lupus erythematosus

Previous studies indicated that bone marrow mesenchymal stem cells (BMSCs) from patients with systemic lupus erythematosus (SLE) exhibited impaired capacities of proliferation, differentiation, secretion of cytokines, and immune modulation. In this study, we aimed to investigate whether apoptosis and senescence of SLE BMSCs were dysregulated. We found that there were increased frequencies of apoptotic and aging SLE BMSCs in comparison with those of normal controls. Notably, levels of Bcl-2 expression in SLE BMSCs were markedly decreased both at mRNA and protein levels. When BMSCs were induced to apoptosis by tumor necrosis factor-α (TNF-α) stimulation in vitro, the Bax and caspase 8 expression in SLE BMSCs was significantly increased at mRNA levels. The activity of caspase 8 was also enhanced in SLE BMSCs. More cytochrome-C-positive pellets in the cytosolic fraction of BMSCs were detected in SLE patients than in normal controls. The expression of Fas and tumor necrosis factor-α receptor 1 in SLE BMSCs was significantly upregulated compared with normal controls, and the serum levels of FasL and TNF-α were also elevated. Moreover, intracellular reactive oxygen species levels of SLE BMSCs were higher than those of normal controls, with the activation of PI3K/AKT/FoxO3 signaling pathway. Taken together, our results demonstrate increased apoptosis and senescence in SLE BMSCs, which may be associated with the pathogenesis of SLE.postprin