Balance control of grid currents for UPQC under unbalanced loads based on matching-ratio compensation algorithm

Abstract In three-phase four-wire systems, unbalanced loads can cause grid currents to be unbalanced, and this may cause the neutral point potential on the grid side to shift. The neutral point potential shift will worsen the control precision as well as the performance of the three-phase four-wire unified power quality conditioner (UPQC), and it also leads to unbalanced three-phase output voltage, even causing damage to electric equipment. To deal with unbalanced loads, this paper proposes a matching-ratio compensation algorithm (MCA) for the fundamental active component of load currents, and by employing this MCA, balanced three-phase grid currents can be realized under 100% unbalanced loads. The steady-state fluctuation and the transient drop of the DC bus voltage can also be restrained. This paper establishes the mathematical model of the UPQC, analyzes the mechanism of the DC bus voltage fluctuations, and elaborates the interaction between unbalanced grid currents and DC bus voltage fluctuations; two control strategies of UPQC under three-phase stationary coordinate based on the MCA are given, and finally, the feasibility and effectiveness of the proposed control strategy are verified by experiment results

Stabilizing the Oxygen Lattice and Reversible Oxygen Redox Chemistry through Structural Dimensionality in Lithium-Rich Cathode Oxides.

Lattice-oxygen redox (l-OR) has become an essential companion to the traditional transition-metal (TM) redox charge compensation to achieve high capacity in Li-rich cathode oxides. However, the understanding of l-OR chemistry remains elusive, and a critical question is the structural effect on the stability of l-OR reactions. Herein, the coupling between l-OR and structure dimensionality is studied. We reveal that the evolution of the oxygen-lattice structure upon l-OR in Li-rich TM oxides which have a three-dimensional (3D)-disordered cation framework is relatively stable, which is in direct contrast to the clearly distorted oxygen-lattice framework in Li-rich oxides which have a two-dimensional (2D)/3D-ordered cation structure. Our results highlight the role of structure dimensionality in stabilizing the oxygen lattice in reversible l-OR, which broadens the horizon for designing high-energy-density Li-rich cathode oxides with stable l-OR chemistry

Pressure-induced superconductivity in charge-density-wave compound LaTe2-xSbx (x=0 and 0.4)

Here, we have grown single crystals of LaTe2-xSbx (x=0 and 0.4) with continuously adjustable CDW. High-pressure x-ray diffraction show LaTe2 does not undergo phase transition and keep robust below 40 GPa. In-situ high-pressure electrical measurements show LaTe2-xSbx undergo semiconductor-metal-superconductivity transition at 4.6 and 2.5 GPa, respectively. With the doping of Sb, the highest Tc increases from 4.6 to 6.5 K. Theoretical calculations reveal that the CDW has been completely suppressed and the calculated Tc is about 2.97 K at 4.5 GPa, consistent with the measured value. Then, the pressure-induced superconductivity in LaTe2-xSbx can be explained in the framework of the BCS theory.Comment: 11 pages, 5 figure

Applications of functional near-infrared spectroscopy in non-drug therapy of traditional Chinese medicine: a review

Non-drug therapies of traditional Chinese medicine (TCM), including acupuncture, massage, tai chi chuan, and Baduanjin, have emerged as widespread interventions for the treatment of various diseases in clinical practice. In recent years, preliminary studies on the mechanisms of non-drug therapies of TCM have been mostly based on functional near-infrared spectroscopy (fNIRS) technology. FNIRS is an innovative, non-invasive tool to monitor hemodynamic changes in the cerebral cortex. Our review included clinical research conducted over the last 10 years, establishing fNIRS as a reliable and stable neuroimaging technique. This review explores new applications of this technology in the field of neuroscience. First, we summarize the working principles of fNIRS. We then present preventive research on the use of fNIRS in healthy individuals and therapeutic research on patients undergoing non-drug therapies of TCM. Finally, we emphasize the potential for encouraging future advancements in fNIRS studies to establish a theoretical framework for research in related fields

Network pharmacology-based analysis of potential mechanisms of myocardial ischemia-reperfusion injury by total salvianolic acid injection

In this review, we investigated the potential mechanism of Total Salvianolic Acid Injection (TSI) in protecting against myocardial ischemia reperfusion injury (MI/RI). To achieve this, we predicted the component targets of TSI using Pharmmapper and identified the disease targets of MI/RI through GeneCards, DisGenNET, and OMIM databases. We constructed protein-protein interaction networks by analyzing the overlapping targets and performed functional enrichment analyses using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. Our analysis yielded 90 targets, which were implicated in the potential therapeutic effects of TSI on MI/RI. Seven critical signaling pathways significantly contributed to TSI’s protective effects, namely, PI3K signaling, JAK-STAT signaling, Calcium signaling, HIF-1 signaling, Nuclear receptor signaling, Cell Cycle, and Apoptosis. Subsequently, we conducted a comprehensive literature review of these seven key signaling pathways to gain further insights into their role in the TSI-mediated treatment of MI/RI. By establishing these connections, our study lays a solid foundation for future research endeavours to elucidate the molecular mechanisms through which TSI exerts its beneficial effects on MI/RI

Liquid-liquid equilibria of UCON + (sodium or potassium) phosphate salt aqueous two-phase systems at 23 °C

Six phase diagrams for UCON−phosphate salt aqueous two-phase systems (ATPSs), at 23 °C, are presented. The ATPSs were obtained combining UCON (a random copolymer of 50 % ethylene oxide and 50 % propylene oxide) and a phosphate salt (KH2PO4, K2HPO4, potassium phosphate buffer pH = 7, NaH2PO4, Na2HPO4, and sodium phosphate buffer pH = 7). Among the salts used, Na2HPO4 proved to be the most effective in ATPS formation, providing the greatest heterogeneous region in the phase diagram. The previous established relation between the anion valence and the concentration needed to form a biphasic system was confirmed: higher valence requires lower concentration. Na+ salts require, in all cases, lower concentration to form ATPSs than the corresponding K+ salts. The size of the heterogeneous region in the phase diagrams increases with an increase of the pH value of the salt used in ATPS preparation.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/43439/2008Fundo Europeu de Desenvolvimento Regional (FEDER) - FEDER/POCI/201

Influence of medium modifications (optimization) on high nematicidal activity of the fermentation broth of Clostridium beijerinckii

Introduction: The nematode species Meloidogyne incognita has been responsible for significant financial losses within the agricultural sector. Nematophagous bacteria, characterised by their extensive distribution and broad spectrum of hosts, exhibit remarkable efficacy as natural antagonists against nematodes. Sneb518 (Clostridium beijerinckii) fermentation broth displayed substantial biocontrol activity against M. incognita in previous research. Optimizing fermentation conditions is a fundamental technique for dramatically enhancing end product performance. There has been no such study conducted yet on enhancing the nematicidal activities of Sneb518 (Clostridium beijerinckii) fermentation using response surface methodology (RSM).Methods: The influence of strain Sneb518 fermentation media and conditions on nematicidal activity was examined using the three-factor technique and a Plackett-Burman design, and the interaction between various fermentation factors was examined using a Box-Behnken design. The present study employed response surface methodology (RSM) to examine and enhance the nematicidal activity of Sneb518 culture filtrates by identifying and optimising the influential components.Results: Glucose, peanut cake flour, and potassium chloride as carbon, nitrogen, and inorganic salts displayed considerably increased nematicidal potential in the present study. Furthermore, the corrected mortality of J2 ranged from 52.24% to 91.15% when utilizing the Box-Behnken design. These findings clearly support the application of RSM for medium optimization. Moreover, the outcomes of the validation experiment corresponded to the model predictions.Discussion: This research has enhanced the biocontrol ability of C. beijerinckii to control M. incognita and this research has led to the advancement of new biocontrol agents

Are Urban Development and Densification Patterns Aligned with Infrastructure Funding Allocation? Examining Data from Melbourne 1999-2015

Densification of cities and suburbs is a contentious issue for many communities in lower-density settings. Local opposition to densification is often premised on concerns about the inadequacy of existing infrastructure to support growing populations and is strongest and most successful in wealthier neighbourhoods. While the urban consolidation agenda in cities such as Melbourne and Sydney is justified in policy contexts as a strategy to improve utilisation of existing infrastructure in built up areas, densification over time also produces new demand for services. Whether or not densification drives new infrastructure spending is therefore an important question in the governance of social justice in densifying cities. Alignment between population growth and infrastructure spending is a crucial condition for communities asked to embrace higher density housing. Where misalignment occurs, those areas that are least resourced may also be those bearing the brunt of population increase and infrastructure stress. Recognising both the social justice and strategic dimensions of the density-infrastructure nexus, this paper examines data on spatial patterns of capital investment and population growth in Victoria (VIC). We focus on spending by the Victorian State Governments in a range of urban infrastructures and services in Melbourne since 1999. The findings highlight the limits and potential of these data and point to some inconsistencies between State Governments\u27 infrastructure spending patterns and their urban development strategies