Due to environmental and fuel cost concerns more and more wind- and solar-based generation units are embedded in distribution networks (DNs). However, a part of such an embedded generation would be ...curtailed due to system constraints and variations of the energy penetration. This part of energy can be recovered by introducing energy storage systems (ESSs) and an optimal dispatch of both active and reactive powers. Therefore, we propose a combined problem formulation for active-reactive optimal power flow (A-R-OPF) in DNs with embedded wind generation and battery storage. The solution provides an optimal operation strategy which ensures the feasibility and enhances the profit significantly. Results of a 41-bus distribution network are presented. It can be demonstrated that more than 12% of energy losses and a large amount of reactive energy to be imported from the transmission network (TN) can be reduced using the proposed approach in comparison to the operation strategy where only active OPF is considered.
Single‐electron transfer (SET) oxidation of ionic hypervalent complexes, in particular alkyltrifluoroborates (Alkyl‐BF3−) and alkylbis(catecholato)silicates (Alkyl‐Si(cat)2−), have contributed ...substantially to alkyl radical generation compared to alkali or alkaline earth organometallics because of their excellent activity–stability balance. Herein, another proposal is reported by using neutral metalloid compounds, Alkyl‐GeMe3, as radical precursors. Alkyl‐GeMe3 shows comparable activity to that of Alkyl‐BF3− and Alkyl‐Si(cat)2− in radical addition reactions. Moreover, Alkyl‐GeMe3 is the first successful group 14 tetraalkyl nucleophile in nickel‐catalyzed cross‐coupling. Meanwhile, the neutral nature of these organogermanes offset the limitation of ionic precursors in purification and derivatization. A preliminary mechanism study suggests that an alkyl radical is generated from a tetraalkylgermane radical cation with the assistance of a nucleophile, which may also result in the development of more non‐ionic alkyl radical precursors with a metalloid center.
Alkyl‐GeMe3 was proven to be an effective radical precursor under visible‐light photocatalysis. The metalloid nature of Ge allows single‐electron transfer (SET) at the neutral Ge center and leads to advantages in separation and derivatization.
Metal‐free carbon nanozymes could be promising with the unique features of intrinsic catalytic ability, structure diversity, and strong tolerance to acidic/alkaline media. However, to date, the study ...of metal‐free carbon nanozymes fell far behind metal‐based nanomaterials, in which, the majority reported much more peroxidase‐like activity than other enzyme‐mimicking behavior (e.g., oxidase). Thus, the exploit of high‐performance carbon nanozymes is of importance but challenging. In this work, the nitrogen‐rich conjugated polymer (Aza‐CPs) with rigid network structure is utilized as precursor to yield N‐doped carbon material QAU‐Z1 in high yield via a direct pyrolysis method. Surprisingly, QAU‐Z1 stood out in oxidase‐like behavior, which significantly outperformed the control materials GNC‐900 and QAU‐Z2 with nucleobase or conjugated small molecule as precursor, respectively. More importantly, it is a crucial revelation that the catalytic performance is closely related to the change of zeta potential for carbon nanozyme during the substrate 3,3′,5,5′‐tetramethylbenzidine oxidation process, as well as its catalytical capacity to O2, which could be insightful to understand the inherent mechanism. This work not only presents the potential of conjugated polymers in constructing highly efficient carbon nanozyme, but also reveals the vital role of interaction mode between the nanozyme and substrate in the catalytic performance.
Nitrogen‐rich conjugated polymer is first utilized as precursor to construct metal‐free N‐doped carbon nanozymes QAU‐Z1, which is almost the best performance among the current metal‐free oxidase‐like nanozymes. The inherent mechanism can be attributed to the zeta potential variation between negative nanozyme and positively‐charged TMB molecules, as well as the capacity of QAU‐Z1 to decrease the overpotential of O2 reduction.
As a new fire detection technology, image fire detection has recently played a crucial role in reducing fire losses by alarming users early through early fire detection. Image fire detection is based ...on an algorithmic analysis of images. However, there is a lower accuracy, delayed detection, and a large amount of computation in common detection algorithms, including manually and machine automatically extracting image features. Therefore, novel image fire detection algorithms based on the advanced object detection CNN models of Faster-RCNN, R–FCN, SSD, and YOLO v3 are proposed in this paper. A comparison of the proposed and current algorithms reveals that the accuracy of fire detection algorithms based on object detection CNNs is higher than other algorithms. Especially, the average precision of the algorithm based on YOLO v3 reaches to 83.7%, which is higher than the other proposed algorithms. Besides, the YOLO v3 also has stronger robustness of detection performance, and its detection speed reaches 28 FPS, thereby satisfying the requirements of real-time detection.
Effective hemostasis is vital to reduce the pain and mortality of patients, and the research and development of hemostatic materials are prerequisite for effective hemostasis. Chitosan (CS), with ...good biodegradability, biocompatibility and non-toxicity, has been widely applied in bio-medicine, the chemical industry, the food industry and cosmetics. The excellent hemostatic properties of CS have been extensively studied. As a result, chitosan-based composite hemostatic materials have been emerging. In this review, the hemostatic mechanism of chitosan is briefly discussed, and then the progress of research on chitosan-based composite hemostatic materials with multiple forms such as films, sponges, hydrogels, particles and fibers are introduced. Finally, future perspectives of chitosan-based composite hemostatic materials are given. The objective of this review is to provide a reference for further research and development of effective hemostatic materials.
Active-reactive optimal power flow (A-R-OPF) in distribution networks (DNs) with embedded wind generation and battery storage systems (BSSs) was proposed recently. The solution was based on a fixed ...length in the charge and discharge cycle for daily operations of BSSs. This can lead to a low profit when the profiles of renewable generators, demand and prices vary from day to day. In this paper, we extend the A-R-OPF method by developing a flexible battery management system (FBMS). This is accomplished by optimizing the lengths (hours) of charge and discharge periods of BSSs for each day, leading to a complex mixed-integer nonlinear program (MINLP). An iterative two-stage framework is proposed to address this problem. In the upper stage, the integer variables (i.e., hours of charge and discharge periods) are optimized and delivered to the lower stage. In the lower stage the A-R-OPF problem is solved by a NLP solver and the resulting objective function value is brought to the upper stage for the next iteration. It can be shown through a case study that a flexible operation strategy will achieve a considerably higher profit than by a fixed operation strategy of BSSs.
Solution approaches to chance constrained programming (CCP) have been recently developed and applied in many areas for optimization under uncertainty. Due to the nonlinear model with multiple ...uncertain variables as well as multiple output constraints, CCP has not been directly applied to optimal power flow (OPF) under uncertainty. The objective of this paper is twofold. First, we introduce the CCP approach to OPF under uncertainty and analyze the computational complexity of the chance constrained OPF. Second, the effectiveness of implementing a back-mapping approach and a linear approximation of the nonlinear model equations to solve the formulated CCP problem is investigated. Load power uncertainties are considered as multivariate random variables with correlated normal distribution. Based on both the nonlinear and the linearized model, results of a five-bus system and the IEEE 30-bus test system are presented to demonstrate the scope of chance constrained OPF.
Plants can recruit beneficial microbes to enhance their ability to defend against pathogens. However, in contrast to the intensively studied roles of the rhizosphere microbiome in suppressing plant ...pathogens, the collective community-level change and effect of the phyllosphere microbiome in response to pathogen invasion remains largely elusive.
Here, we integrated 16S metabarcoding, shotgun metagenomics and culture-dependent methods to systematically investigate the changes in phyllosphere microbiome between infected and uninfected citrus leaves by Diaporthe citri, a fungal pathogen causing melanose disease worldwide. Multiple microbiome features suggested a shift in phyllosphere microbiome upon D. citri infection, highlighted by the marked reduction of community evenness, the emergence of large numbers of new microbes, and the intense microbial network. We also identified the microbiome features from functional perspectives in infected leaves, such as enriched microbial functions for iron competition and potential antifungal traits, and enriched microbes with beneficial genomic characteristics. Glasshouse experiments demonstrated that several bacteria associated with the microbiome shift could positively affect plant performance under D. citri challenge, with reductions in disease index ranging from 65.7 to 88.4%. Among them, Pantoea asv90 and Methylobacterium asv41 identified as "recruited new microbes" in the infected leaves, exhibited antagonistic activities to D. citri both in vitro and in vivo, including inhibition of spore germination and/or mycelium growth. Sphingomonas spp. presented beneficial genomic characteristics and were found to be the main contributor for the functional enrichment of iron complex outer membrane receptor protein in the infected leaves. Moreover, Sphingomonas asv20 showed a stronger suppression ability against D. citri in iron-deficient conditions than iron-sufficient conditions, suggesting a role of iron competition during their antagonistic action.
Overall, our study revealed how phyllosphere microbiomes differed between infected and uninfected citrus leaves by melanose pathogen, and identified potential mechanisms for how the observed microbiome shift might have helped plants cope with pathogen pressure. Our findings provide novel insights into understanding the roles of phyllosphere microbiome responses during pathogen challenge. Video abstract.
Long noncoding RNAs (lncRNAs) have emerged as important components of gene regulatory network in embryonic stem cells (ESCs). However, the function and molecular mechanism of lncRNAs are still ...largely unknown. Here we identifies Trincr1 (TRIM71 interacting long noncoding RNA 1) lncRNA that regulates the FGF/ERK signaling and self-renewal of ESCs. Trincr1 is exported by THOC complex to cytoplasm where it binds and represses TRIM71, leading to the downregulation of SHCBP1 protein. Knocking out Trincr1 leads to the upregulation of phosphorylated ERK and ERK pathway target genes and the decrease of ESC self-renewal, while knocking down Trim71 completely rescues the defects of Trincr1 knockout. Furthermore, ectopic expression of Trincr1 represses FGF/ERK signaling and the self-renewal of neural progenitor cells (NPCs). Together, this study highlights lncRNA as an important player in cell signaling network to coordinate cell fate specification.
Electrochemical oxidation represents an environmentally friendly solution to conventional methods that require caustic stoichiometric chemical oxidants. However, C–H functionalizations merging ...transition-metal catalysis and electrochemical techniques are, to date, largely confined to the use of precious metals and divided cells. Herein, we report the first examples of copper-catalyzed electrochemical C–H aminations of arenes at room temperature using undivided electrochemical cells, thereby providing a practical solution for the construction of arylamines. The use of n-Bu4NI as a redox mediator is crucial for this transformation. On the basis of mechanistic studies including kinetic profiles, isotope effects, cyclic voltammetric analyses, and radical inhibition experiments, the reaction appears to proceed via a single-electron-transfer (SET) process, and a high valent Cu(III) species is likely involved. These findings provide a new avenue for transition-metal-catalyzed electrochemical C–H functionalization reactions using redox mediators.
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