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With the microgrids large-scale interconnect to the power grid, a number of neighboring microgrids in a certain region will form a multi-microgrids (MMGs) system. In the development from microgrid to smart grid, the MMGs will be a new research hotspot after microgrid. The paper analyses the basic structure of the MMGs from many aspects such as voltage grade classification, AC/DC constitutional forms, and phase-sequence constitutional forms. Next the remote-area type, residential-area type, office-building type, industrial-park type and research-study type MMGs are analyzed according to the typical application scenarios. Lastly, based on the research of the four aspects of the planning and design, mode switching, optimal operation and control devices, the key technology of the MMGs is discussed and explored. [ABSTRACT FROM AUTHOR]

Abstract: Colony formation of Microcystis plays a significant role in Microcystis blooms. Calcium (Ca) and magnesium (Mg) are important nutrient elements during algae growth. In this study, the influences of Ca and Mg concentrations on extracellular polysaccharides (EPS) content and colony formation of Microcystis were investigated, and then the effects of EPS content and specific growth rate on colony formation were discussed. The results showed that Ca had a direct observable influence on the colony formation of Microcystis; however, Mg was not obvious. More specifically, when Ca concentration was lower than 20 mg•L-1, the Microcystis was dominated by single cells, when the concentration was over 20 mg•L-1, Microcystis colonies were found and took up more than 50%, and the size of colony was increased with the increasing Ca concentration. Moreover, it showed that the mean size of Microcystis had significant correlation with EPS content, and lower specific growth rate was in favor of colony formation. [Copyright &y& Elsevier]

The aim of the work described here was to investigate the value of point-of-care ultrasound (POCUS) in the early assessment of the severity of pulmonary edema in rabbits. A rabbit oleic acid (OA)-induced pulmonary edema model was used. Thirty-two New Zealand rabbits were randomly divided into four groups: a control group and three pulmonary edema groups (mild, moderate and severe). Features of transthoracic B-line artifacts (BLA), blood pH, PaO2 and PaCO2, serum inflammatory factors, lung coefficient (LC), lung wet-to-dry weight ratio (W/D) and lung histopathology were assessed. BLA features and severity of pulmonary edema were semiquantitatively scored. Correlations between the number of BLA and PaO2, PaCO2, serum inflammatory factors, LC and W/D were analyzed. An additional 8 rabbits with severe pulmonary edema were used as the verified group, in which the lung was divided into ex vivo BLA (BLA-ev)-free (BLA-ev-free) and BLA-ev-clustered subregions depending on the features of BLA-ev recorded by ex vivo lung ultrasound. Lung specimens from each subregion were collected for histopathological examination. Relationships between features of BLA-ev and lung histopathological abnormalities were analyzed. With increasing doses of OA, number of BLA, W/D and levels of serum inflammatory factors decreased. Meanwhile, lung pathologic abnormalities were aggravated. In addition, time of appearance of BLA, blood pH and PaO2, and PaCO2 decreased dose dependently on OA (p < 0.05). Number of BLA was linear positively correlated with severity of pulmonary edema (r = 0.953, p < 0.05). Consistently, the features of BLA-ev reflected the severity of lung histopathological abnormalities (r = 0.936, p < 0.05). Thus, POCUS is useful in the early quantitative assessment of the severity of pulmonary edema. [ABSTRACT FROM AUTHOR]