DataSheet1_Transient synchronization stability of photovoltaics integration by singular perturbation analysis.pdf

The integration of large-scale photovoltaics (PVs) into the power grid has significantly altered the transient synchronization dynamics of traditional power systems dominated by synchronous generators (SGs) and posed great challenges to modeling and analysis of PVs integration. In this paper, the transient synchronization stability of the PV-SG system is studied using the singular perturbation technique. Firstly, a nonlinear model of a PV-SG system is established to reveal the multiscale transient synchronization characteristics. Further, the full system is decomposed into a slow subsystem and a fast subsystem by the singular perturbation technique. The fast subsystem containing the dynamics of the DC voltage control, terminal voltage control, and phase-locked loop, and the slow subsystem containing the dynamics of rotor motion can perfectly reflect the dynamics of the full system within the electromagnetic and electromechanical timescales, respectively. The proposed model provides a clearer physical picture of dynamics in the PV-SG system within the electromagnetic and electromechanical timescales. Subsequently, the stability of the slow and fast subsystems is investigated using the energy function and eigenvalue analysis methods, respectively. Meanwhile, the impacts of various operating, control, and structural parameters on the transient synchronization stability are uncovered. Different from the most existing research endeavors on the wide simulations of the PVs integration, the impact of PVs on the synchronization dynamics of SGs without considering the dynamical characteristics of the PV system, and the transient synchronization stability analyses of the PLL-based voltage source converter systems, it is the key contribution to study the transient synchronization dynamical characteristics of the PV system and its interaction with the SG under different timescales. All these are helpful and easy to extend to more complicated PV-SG systems. Finally, the analysis results are validated by extensive simulations.</p

Additional file 1: of Denosumab compared to bisphosphonates to treat postmenopausal osteoporosis: a meta-analysis

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Additional file 1 of Exploration of key factors in Gingival Crevicular fluids from patients undergoing Periodontally Accelerated Osteogenic Orthodontics (PAOO) using proteome analysis

Supplementary Material

Dynamics of the population sizes and tMRCAs of all Asian black bears, the Japanese population and the continental population.

<p>(a) Dynamics of the population sizes estimated by Bayesian Skyline Plot analysis. The y-axes indicates the effective population size × generation intervals, and the x-axes indicate the time in years before present. (b) Posterior distributions of the tMRCAs. The times of formation of land bridges before the oldest record of the Japanese black bear (337–330 Kilo annum) are indicated by shaded bars, following Dobson and Kawamura [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136398#pone.0136398.ref060" target="_blank">60</a>] and Rohling et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136398#pone.0136398.ref063" target="_blank">63</a>] with recalibrations by Lisiecki and Raymo [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136398#pone.0136398.ref067" target="_blank">67</a>]. The shading around the lines indicates 95% confidence interval of effective population size for each time point.</p

Phylogeographic and Demographic Analysis of the Asian Black Bear (<i>Ursus thibetanus</i>) Based on Mitochondrial DNA

<div><p>The Asian black bear <i>Ursus thibetanus</i> is widely distributed in Asia and is adapted to broad-leaved deciduous forests, playing an important ecological role in the natural environment. Several subspecies of <i>U</i>. <i>thibetanus</i> have been recognized, one of which, the Japanese black bear, is distributed in the Japanese archipelago. Recent molecular phylogeographic studies clarified that this subspecies is genetically distantly related to continental subspecies, suggesting an earlier origin. However, the evolutionary relationship between the Japanese and continental subspecies remained unclear. To understand the evolution of the Asian black bear in relation to geological events such as climatic and transgression-regression cycles, a reliable time estimation is also essential. To address these issues, we determined and analyzed the mt-genome of the Japanese subspecies. This indicates that the Japanese subspecies initially diverged from other Asian black bears in around 1.46Ma. The Northern continental population (northeast China, Russia, Korean peninsula) subsequently evolved, relatively recently, from the Southern continental population (southern China and Southeast Asia). While the Japanese black bear has an early origin, the tMRCAs and the dynamics of population sizes suggest that it dispersed relatively recently in the main Japanese islands: during the late Middle and Late Pleistocene, probably during or soon after the extinction of the brown bear in Honshu in the same period. Our estimation that the population size of the Japanese subspecies increased rapidly during the Late Pleistocene is the first evidential signal of a niche exchange between brown bears and black bears in the Japanese main islands.</p><p>This interpretation seems plausible but was not corroborated by paleontological evidence that fossil record of the Japanese subspecies limited after the Late Pleistocene. We also report here a new fossil record of the oldest Japanese black bear from the Middle Pleistocene, and it supports our new evolutionary hypothesis of the Japanese black bear.</p></div

Genealogy of eight Asian black bears as inferred from the 3rd codon positions of the complete mitochondrial protein genes using the GENETREE program.

<p>Since the program did not work on the whole data set, probably due to excessive numbers of mutation sites, the whole data set was separated into six fragments. The dots on the branches indicate the number of mutation sites. The values of ρ_ML (= 2×Nef×μ; μ is the mutation rate per sequence per generation) and tMRCAs were also estimated by GENETREE. The substitution rate of the 3rd codon positions of mitochondrial protein genes of Asian black bear was estimated to be 3.03×10⁻⁸/site/year (data not shown), and the average mutation rate of each of the six fragments is 5.99×10⁻⁵/sequence/generation.</p

Summary Statistics for the demography.

<p>N: numbers of the samples</p><p>Θπ: Theta based on the nucleotide diversity</p><p>Θw: Waterson's theta</p><p>*All of them were not significant in this study (p-values> 0.1)</p><p>Summary Statistics for the demography.</p

Divergence times of the family Ursidae.

<p>Nodal numbers indicate the estimated divergence time (Ma). Horizontal gray bars spanning the nodes mark the 95% confidence interval for the divergence time. The phylogenetic positions of extinct lineages, which are indicated by the dashed lines, follow [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136398#pone.0136398.ref018" target="_blank">18</a>]. Horizontal black bars indicate temporal range based on fossil evidence. The temporal range of the common ancestor of Ursidae based on fossil evidence is indicated by the shading. Extinct species are marked by a dagger (†).</p

Middle Pleistocene black bear from Japan with a comparison of the left upper second molars (M2) among bears.

<p>1, Middle Pleistocene (ca. 337–330 Kilo annum, MIS 9 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136398#pone.0136398.ref068" target="_blank">68</a>]) black bear, <i>Ursus thibetanus</i> subsp. indet., from Aomori Prefecture, northern Japan (NMNS-PV 22666). 2, Extant Japanese black bear, <i>Ursus thibetanus japonicus</i>, from Nagano Prefecture, central Japan (NMNS-PO 52). 3, Extant Tibetan black bear, <i>Ursus thibetanus thibetanus</i>, from Thailand (NMNS-PO 207). 4, Extant Hokkaido brown bear, <i>Ursus arctos yesoensis</i>, from Hokkaido, northern Japan (NMNS-PO 208). The black bears share a combination of M2 characters such as a relatively large metacone (as large as the paracone), a distinct constriction between the paracone and the metacone, and a less developed posterior talon. In contrast, the brown bear has a smaller metacone relative to the paracone, a less distinct constriction between the two cusps, and a well developed posterior talon in M2. These comparisons suggest that the tooth of Middle Pleistocene Japanese black bear is closer in size and shape to the teeth of continental black bears than it is to extant Japanese black bears, but it is far from the brown bears.</p

Coalescent times of the Asian black bear.

<p>Nodal numbers indicate the estimated coalescent time (Ma). Horizontal gray bars show the 95% confidence interval for the coalescent times. (a-c) Geographical distribution of fossils of Asian black bear in (a) the Calabrian (Early Pleistocene) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136398#pone.0136398.ref058" target="_blank">58</a>], (b) the lonian (Middle Pleistocene) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136398#pone.0136398.ref058" target="_blank">58</a>, Kohno, unpublished] and (c) the Tarantian (Late Pleistocene) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136398#pone.0136398.ref058" target="_blank">58</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0136398#pone.0136398.ref060" target="_blank">60</a>]. The illustration is of a Japanese black bear (<i>Ursus thibetanus japonicus</i>), kindly provided by Utako Kikutani. Circles on maps indicate the fossil record of Asian black bears (Blue circles indicate the fossil records reported by previous studies and red circle indicates the fossil records newly reported by this study.).</p