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Developing photovoltaic (PV) and wind power is one of the most efficient approaches to reduce carbon emissions. Accumulating the PV and wind energy resources at different geographical locations can minimize total power output variance as injected into the power systems. To some extent, a low degree of the variance amplitude of the renewable resources can reduce the requirement of in-depth regulation and dispatch for the fossil fuel-based thermal power plants. Such an issue can alternatively reduce carbon emissions. Thus, the correlation problem by minimizing the variance of total PV and wind power plays a vital role in power system planning and operation. However, the synergistic effect of power output correlation is mainly considered on the generation side, and it is often neglected for the correlation relationship between the power grid components. To address this problem, this paper proposes a correlation coefficient analysis method for the power grid, which can quantify the relationship between energy storage and the probabilistic power flow (PPF) of the grid. Subsequently, to accelerate the mapping efficiency of power correlation coefficients, a novel deep neural network (DNN) optimized by multi-task learning and attention mechanism (MA-DNN) is developed to predict power flow fluctuations. Finally, the simulation results show that in IEEE 9-bus and IEEE14-bus systems, the strong correlation grouping percentage between the power correlation coefficients and power flow fluctuations reached 92% and 51%, respectively. The percentages of groups indicating weak correlation are 4% and 38%. In the modified IEEE 23-bus system, the computational accuracy of MA-DNN is improved by 37.35% compared to the PPF based on Latin hypercube sampling. Additionally, the MA-DNN regression prediction model exhibits a substantial improvement in assessing power flow fluctuations in the power grid, achieving a speed enhancement of 758.85 times compared to the conventional probability power flow algorithms. These findings provide the rapid selection of the grid access point with the minimum power flow fluctuations. [ABSTRACT FROM AUTHOR]

With the continuous expansion of the scale of power generated by grid-connected renewable energy, the form and operation characteristics of power grids have undergone significant changes, and the power electronic characteristics of power systems are prominent, resulting in the frequent occurrence of wide-band oscillation problems when renewable energy power generation equipment is connected to a power grid. Oscillation has the characteristics of nonlinearity and has an oscillation frequency ranging from a few hertz to several thousand hertz or more, which seriously threatens the stable operation of power grids. This paper summarizes the wide-band oscillation events that occur worldwide under the background of renewable energy access to power grids, classifies the wide-band oscillation events according to the distribution of oscillation frequency bands, and sorts out the characteristics of various oscillations. From the perspectives of the source side and network side, the existing oscillation suppression measures are classified and prospected. [ABSTRACT FROM AUTHOR]

The intestinal mucosa serves both as a conduit for the uptake of food-derived nutrients and microbiome-derived metabolites, and as a barrier that prevents tissue invasion by microorganisms and tempers inflammatory responses to the myriad contents of the lumen. How the intestine coordinates physiological and immune responses to food consumption to optimize nutrient uptake while maintaining barrier functions remains unclear. Here we show in mice how a gut neuronal signal triggered by food intake is integrated with intestinal antimicrobial and metabolic responses that are controlled by type-3 innate lymphoid cells (ILC3).sup.1-3. Food consumption rapidly activates a population of enteric neurons that express vasoactive intestinal peptide (VIP).sup.4. Projections of VIP-producing neurons (VIPergic neurons) in the lamina propria are in close proximity to clusters of ILC3 that selectively express VIP receptor type 2 (VIPR2; also known as VPAC2). Production of interleukin (IL)-22 by ILC3, which is upregulated by the presence of commensal microorganisms such as segmented filamentous bacteria.sup.5-7, is inhibited upon engagement of VIPR2. As a consequence, levels of antimicrobial peptide derived from epithelial cells are reduced but the expression of lipid-binding proteins and transporters is increased.sup.8. During food consumption, the activation of VIPergic neurons thus enhances the growth of segmented filamentous bacteria associated with the epithelium, and increases lipid absorption. Our results reveal a feeding- and circadian-regulated dynamic neuroimmune circuit in the intestine that promotes a trade-off between innate immune protection mediated by IL-22 and the efficiency of nutrient absorption. Modulation of this pathway may therefore be effective for enhancing resistance to enteropathogens.sup.2,3,9 and for the treatment of metabolic diseases. Feeding controls a neuroimmune circuit comprising VIP-producing neurons and type-3 innate lymphoid cells that helps to regulate the efficiency of nutrient uptake and IL-22-mediated immune protection in the intestine., Author(s): Jhimmy Talbot [sup.1] , Paul Hahn [sup.1] , Lina Kroehling [sup.1] , Henry Nguyen [sup.1] , Dayi Li [sup.1] , Dan R. Littman [sup.1] [sup.2] Author Affiliations: (1) Molecular [...]

With the increase in capacitor voltage transformer (CVT) operation life, CVT impedance changes, and the short-time switching of overhead lines, it is very easy to cause a transient oscillation accident in which a CVT participates, reduce the insulation level of a CVT, and even induce regional power grid oscillation and easily cause capacitor breakdown, after long-term operation with defects. In this paper, the whole power network, including the generator, power grid, and consumer, is modeled, and the theoretical model of the CVT ferro-resonance connected grid is built. The frequency spectrum analysis, and the measurements of resonance bus voltage and line voltage, were carried out to find the design method of a fast saturation damper (FSD) and its voltage–current characteristics that affect the vibration, based on theory and practice; this paper puts forward effective measures to reduce the resonance effect of a CVT in operation, and avoid the oscillation of the line and even the regional power grid system. [ABSTRACT FROM AUTHOR]

In this paper, a novel principle of an active power filter based on the harmonic impedance control of a transformer is proposed for high-voltage power distribution systems application. A linear transformer with multiple secondary windings is adopted. The primary winding is shunted with harmonic-producing loads, while the secondary windings are connected with inverters. The primary harmonic current is detected and then tracked by the inverters with fixed compensation coefficient. When the harmonic current compensation condition is satisfied, the transformer can really exhibit nearly zero impedance to harmonic current and primary self-impedance to fundamental current. As a result, the harmonic currents in power systems can be led to flow into the transformer branch. The operation principle, the control scheme, and the harmonic current detection method are discussed in detail. Finally, simulated waveforms and experimental results are presented to verify the effectiveness of the active power filter. Index Terms--Active power filter, harmonic impedance, high power, high voltage, linear, multiple windings, power distribution systems, pulsewidth-modulated (PWM) inverter, transformer.

In this paper, a novel transformer structure is proposed in order to manufacture a high-power active filtering device. The novel transformer structure contains one primary and multiple secondary windings. The system configuration and compensation principle are addressed in detail. The fundamental magnetic flux compensation in the case of the transformer with multiple secondary windings is fulfilled. In addition, a three-phase active power filter topology consisting of three independent transformers with multiple secondary windings is presented so that the filter can run under unbalanced loads. The parameters of hysteresis current control are also analyzed in detail. A simple and practical fundamental detecting approach is discussed. Transient response and fault protection schemes are explained. A set of automatic threel-phase active power filtering devices has been constructed and operated in the field. The field test results verify the validity of the novel transformer structure and the active power filtering system. Index Terms--Active power filter, fundamental, high power, hysteresis control, magnetic flux, multiple windings, phase shift, switched-capacitor filter, three-phase, transformer, unbalanced.

In this paper, a novel practical principle of series hybrid active power filter based on the fundamental magnetic flux compensation (FMFC) of a series transformer is proposed. In the active power filter, the fundamental current component of power utility is detected and tracked to produce a fundamental compensation current, which is injected into the secondary winding. According to the law of superposition, when the injected fundamental current and the fundamental current component of the power utility satisfy the FMFC, the series transformer can really exhibit very low impedance to fundamental and naturally magnetizing impedance to harmonics. As a result, the series hybrid active power filter with FMFC really acts as a 'harmonic isolator'. The current control scheme and fundamental detecting method are analyzed. The validity of the novel principle and excellent filtering characteristics are verified by the experimental results of the two kinds of typical harmonic-producing loads. Index Terms--Active power filter, Fourier series, fundamental, harmonic, hysteresis control, magnetic flux, passive filters, PWM inverter, transformer.

We investigated the power-frequency bistability of a grating external cavity laser diode (ECLD), which operates in the strong feedback regime, by studying the threshold carrier density and related refractive index. The frequency width of the hysteresis loop has been expressed in an explicit analytical form in terms of the linewidth enhancement factor, and the reflectivities of the external grating reflector as well as the diode facet that faces it.

An examination of different hysteresis loop shapes on power-frequency curves is presented. Topics include refractive index, carrier density, and reference carrier density.

The winding theory is a crucial tool for analyzing the electric machines. However, some special phenomena in short primary linear machines (SPLMs) cannot be explained by the traditional theory, which is commonly applied in rotary machines (RMs). In this paper, an improved winding theory for SPLMs is presented. Starting with the magnetic field produced by a single conductor, the difference between winding theory for SPLMs and RMs is analyzed. According to the proposed theory, the pulsating magneto-motive force (MMF) and the asymmetry of the three-phase windings can be analyzed and calculated in details. It is very useful for perceiving, analysis and optimal design for the winding in SPLMs. The proposed theory is verified by 2-D finite-element analysis (FEA) and experiment. [ABSTRACT FROM AUTHOR]

We demonstrate the power of Gibbs point process models from the spatial statistics literature when applied to studies of resolved galaxies. We conduct a rigorous analysis of the spatial distributions of objects in the star formation complexes of M33, including giant molecular clouds (GMCs) and young stellar cluster candidates (YSCCs). We choose a hierarchical model structure from GMCs to YSCCs based on the natural formation hierarchy between them. This approach circumvents the limitations of the empirical two-point correlation function analysis by naturally accounting for the inhomogeneity present in the distribution of YSCCs. We also investigate the effects of GMCs' properties on their spatial distributions. We confirm that the distribution of GMCs and YSCCs are highly correlated. We found that the spatial distributions of YSCCs reaches a peak of clustering pattern at ∼250 pc scale compared to a Poisson process. This clustering mainly occurs in regions where the galactocentric distance ≳4.5 kpc. Furthermore, the galactocentric distance of GMCs and their mass have strong positive effects on the correlation strength between GMCs and YSCCs. We outline some possible implications of these findings for our understanding of the cluster formation process. [ABSTRACT FROM AUTHOR]

A novel variable reactor is presented in this paper. The principle of the novel variable reactor is simply addressed. The equivalent impedance of primary winding of the transformer will vary with the ratio between the primary and the secondary voltages. For the proposed variable reactor, a novel series power quality controller (SPQC) is developed and its principle is analyzed in detail. The SPQC greatly improves the power utility impedance to harmonics instead of the fundamental and plays the role of isolating the harmonics. Because the novel SPQC is with very high impedance to harmonics, the passive power filter can be reduced. Accordingly, three kinds of reduced single-phase passive power filters are presented. The comparison criterion of reducing passive power filter is described. The SPQC is characterized by perfectly isolating the harmonics, simplified passive power filter design, small rating, and being suitable for two kinds of harmonic sources. The validity of the novel SPQC and excellent filtering characteristic are verified by the experimental results. [ABSTRACT FROM PUBLISHER]

A novel variable reactor based on transformer is proposed in the paper. In the variable reactor, a transformer with air gap is chosen, and the primary voltage is detected and used as the reference signal. A voltage-sourced inverter is applied to track the reference signal in order to yield a controllable voltage, which is applied across the secondary winding of the transformer. When the secondary-controlled voltage and the primary voltage satisfy a proportional condition, the equivalent impedance of primary winding of the transformer will vary continuously. According to the novel variable reactor, a novel shunt power quality controller is proposed and its principle is analyzed in detail. The shunt power quality controller is characterized by parallel topology and single frequency control. The approaches of decreasing the transformer leakage inductance are addressed. The experimental results verify the validity of the shunt power quality controller. [ABSTRACT FROM AUTHOR]

A novel variable reactor based on magnetic flux control is proposed in this paper. The system configuration of the novel variable reactor is presented, while its operational principle and dynamic performance are analyzed. Based on the developed variable reactor, a novel integrated power quality controller (IPQC) suitable for microgrid is proposed, which can cater for the peculiar requirements of microgrid power quality, such as the harmonic high penetration, frequent voltage fluctuation and overcurrent phenomenon, and bidirectional power flow and small capacity. For the fundamental, the equivalent impedance of the primary winding is a variable reactor or capacitor. For the $n$th-order harmonic, the equivalent impedance is very high impedance and acts as a “harmonic isolator.” The system control strategy is also analyzed in detail. A set of three-phase IPQC has been constructed. The experimental test results verify the validity of the novel variable reactor and the IPQC. [ABSTRACT FROM PUBLISHER]

Insertion of the expression for a Gaussian beam into Maxwell's equations leads to four coupled equations governing the evolution of beam parameters in a logarithmically saturable nonlinear medium (LSNM). Analytical solutions to the coupled equations have been deduced for cases where the incident beam parameters slightly deviate from those of the spatial soliton. As a result, a detailed description to the Gaussian-type breath mode can be made. For general cases, a graphical analysis has been used to draw the main characteristics of the Gaussian-type breath mode propagating along the LSNM. [ABSTRACT FROM AUTHOR]

Provides information on a study of a one-facet AR-coated semiconductor diode laser. Information on the graphic analysis of the study; Conclusion reached on the study.

Targeting glycolysis has been considered therapeutically intractable owing to its essential housekeeping role. However, the context-dependent requirement for individual glycolytic steps has not been fully explored. We show that CRISPR-mediated targeting of glycolysis in T cells in mice results in global loss of Th17 cells, whereas deficiency of the glycolytic enzyme glucose phosphate isomerase (Gpi1) selectively eliminates inflammatory encephalitogenic and colitogenic Th17 cells, without substantially affecting homeostatic microbiota-specific Th17 cells. In homeostatic Th17 cells, partial blockade of glycolysis upon Gpi1 inactivation was compensated by pentose phosphate pathway flux and increased mitochondrial respiration. In contrast, inflammatory Th17 cells experience a hypoxic microenvironment known to limit mitochondrial respiration, which is incompatible with loss of Gpi1. Our study suggests that inhibiting glycolysis by targeting Gpi1 could be an effective therapeutic strategy with minimum toxicity for Th17-mediated autoimmune diseases, and, more generally, that metabolic redundancies can be exploited for selective targeting of disease processes. • PPP and OXPHOS compensate for Gpi1 loss in Th17 cells in normoxic environment • Gpi1 is essential in hypoxic inflamed tissue due to reduced OXPHOS compensation • Metabolic redundancy can vary according to the microenvironment • Targeting Gpi1 could be a tolerable approach for therapeutic glycolysis inhibition Metabolic redundancy differs according to microenvironments, making the glycolysis gene Gpi1 dispensable for homeostatic Th17 cells in normal tissue but essential for pathogenic Th17 cells in hypoxic inflamed tissue. [ABSTRACT FROM AUTHOR]

Lymphoid cells that produce interleukin (IL)-17 cytokines protect barrier tissues from pathogenic microbes but are also prominent effectors of inflammation and autoimmune disease. T helper 17 (Th17) cells, defined by RORγt-dependent production of IL-17A and IL-17F, exert homeostatic functions in the gut upon microbiota-directed differentiation from naive CD4+ T cells. In the non-pathogenic setting, their cytokine production is regulated by serum amyloid A proteins (SAA1 and SAA2) secreted by adjacent intestinal epithelial cells. However, Th17 cell behaviors vary markedly according to their environment. Here, we show that SAAs additionally direct a pathogenic pro-inflammatory Th17 cell differentiation program, acting directly on T cells in collaboration with STAT3-activating cytokines. Using loss- and gain-of-function mouse models, we show that SAA1, SAA2, and SAA3 have distinct systemic and local functions in promoting Th17-mediated inflammatory diseases. These studies suggest that T cell signaling pathways modulated by the SAAs may be attractive targets for anti-inflammatory therapies. • SAAs direct a distinct Th17 cell differentiation program independently of TGF-β • Expression of SAAs is associated with inflamed colon of IBD patients • Systemic SAAs in serum promote differentiation of pathogenic Th17 cells • Local SAA expression fuels pathogenicity of activated Th17 cells Serum amyloid A proteins dictate the balance between homeostatic and inflammatory Th17 cells. [ABSTRACT FROM AUTHOR]