Search

With the increasing penetration of distributed power sources, the stochastic and fluctuating nature of distributed power sources poses a great challenge to the reactive power optimization of the distribution network system. In this study, a dynamic reactive power optimization model with two-stage robust optimization is established, proposing whether the energy storage is charged or discharged. The number of groups of group-switching capacitors is taken as the variables in the first stage. The power of the energy storage charging and discharging and the amount of static reactive power compensator compensation are placed in the second stage. The control strategy in the first stage ensures that the control strategy in the second stage can maintain the safe and stable operation of the distribution network under the worst scenarios. The grid-storage joint optimization technology based on distributed architecture establishes an optimization planning model for the distribution network energy storage system with the goal of optimal technical and economic performance of the transmission and distribution network and considering the constraints of safe and stable operation of the transmission and distribution network, respectively. The PG&E-69 node system arithmetic example is used to verify the effectiveness and feasibility of the proposed model and algorithm. The results of the arithmetic example show that the strategy obtained based on the robust optimization model can achieve voltage magnitude stability within the safety range of 1.0-1.05 p.u. in the simulation scenario that has the best economy. At the same time, the mismatches of each distribution system under cooperative planning are all 0, which indicates that the proposed optimization strategy can fully cooperate with the resources of transmission and distribution networks, promote the safe consumption of clean energy, effectively improve the economy of transmission and distribution networks, and achieve the goal of “mutual benefit and win-win”.

In order to improve the economy of microgrid construction and operation, and meet the personalized demand for reliability of various types of microgrids, an integrated flexible planning method for microgrid is proposed to adapt to multiple scenarios. Based on the judgment results of type and composition, a two-layer model including capacity planning and grid planning is established. The lower-level capacity planning takes the minimum operation cost of micro-source construction as the goal and adopts the mixed integer optimization algorithm to solve it. The upper layer grid planning takes the minimum cost of network construction and operation as the goal, and uses the particle swarm optimization algorithm to solve it. A closed-loop integrated planning system consisting of judgment, capacity planning, and grid planning is formed. The system can meet the personalized reliability requirements of different microgrids by flexibly adjusting the independent operation duration constraints and the load outage attention parameters. The example shows that the proposed method can effectively reduce the construction and operation cost of microgrid, and has a good adaptability to different types and components and different reliability requirements.

Optical detection is an indispensable part of microfluidic systems for nutrient determination in seawater. Coupling total internal reflection capillaries with microfluidic chips is a practical alternative to increase the optical path length for high-sensitivity and a low detection limit in colorimetric assays, which has not been applied in microfluidic devices for seawater nutrients. Here, we present an online microfluidic system which integrated a total internal reflection capillary made of Teflon AF 2400 for the high-sensitivity detection of nitrite and nitrate in seawater. The off-chip capillary lengthens the optical path without changing the internal flow path of the microfluidic chip, enhancing the sensitivity, reducing the detection limit and widening the dynamic range of the system, which significantly improves the performance of the microfluidic system based on wet-chemistry. The detection limit for nitrite is 0.0150 μM using an external 20 cm capillary and 0.0936 μM using an internal 5 cm absorption cell, providing an over 6-fold improvement. Laboratory analysis of surface seawater samples collected from the South China Sea with this system and a one-month online deployment of an autonomous analyzer developed based on this system at a station revealed correlations between the nitrite and nitrate with tide, salinity and chlorophyll over slight variations and narrow ranges, demonstrating the high-sensitivity of this method. [ABSTRACT FROM AUTHOR]

Background: Germline mutations have been identified in a small number of hereditary cancers, but the genetic predisposition for many familial cancers remains to be elucidated. Methods: This study identified a Chinese pedigree that presented different cancers (breast cancer, BRCA; adenocarcinoma of the esophagogastric junction, AEG; and B‐cell acute lymphoblastic leukemia, B‐ALL) in each of the three generations. Whole‐genome sequencing and whole‐exome sequencing were performed on peripheral blood or bone marrow and cancer biopsy samples. Whole‐genome bisulfite sequencing was conducted on the monozygotic twin brothers, one of whom developed B‐ALL. Results: According to the ACMG guidelines, bioinformatic analysis of the genome sequencing revealed 20 germline mutations, particularly mutations in the DNAH11 (c.9463G > A) and CFH (c.2314G > A) genes that were documented in the COSMIC database and validated by Sanger sequencing. Forty‐one common somatic mutated genes were identified in the cancer samples, displaying the same type of single nucleotide substitution Signature 5. Meanwhile, hypomethylation of PLEK2, MRAS, and RXRA as well as hypermethylation of CpG island associated with WT1 was shown in the twin with B‐ALL. Conclusions: These findings reveal genomic alterations in a pedigree with multiple cancers. Mutations found in the DNAH11, CFH genes, and other genes predispose to malignancies in this family. Dysregulated methylation of WT1, PLEK2, MRAS, and RXRA in the twin with B‐ALL increases cancer susceptibility. The similarity of the somatic genetic changes among the three cancers indicates a hereditary impact on the pedigree. These familial cancers with germline and somatic mutations, as well as epigenomic alterations, represent a common molecular basis for many multiple cancer pedigrees. [ABSTRACT FROM AUTHOR]

Using Fe-modified biochar (Fe-B) to capture phosphorus in eutrophic water and then reusing it as a phosphorus fertilizer for agricultural production is a sustainable way to remediate surface water eutrophication and develop agriculture. However, the adsorption efficiency of Fe-modified biochar is influenced by a variety of factors including methods to produce biochar and surface water environment. In this review, we analyze different methods to manufacture Fe-B and their efficacy for phosphate adsorption. Other factors we analyzed include pH value, coexisting ions, biochar application rate, temperature which have shown to affect the capacity of Fe-B to adsorb phosphorus. We also discuss the potential of Fe-B and the phosphorus it adsorbed to be reused as a slow-release phosphorus fertilizer for agricultural production, as well as the perspective of Fe -modified biochar (Fe-B) and its applications. [ABSTRACT FROM AUTHOR]