Clathrodictyids are the most abundant stromatoporoids in the Upper Ordovician Xiazhen Formation (middle to upper Katian) of South China. A total of nine species belonging to four clathrodictyid genera are identified in the formation, including Clathrodictyon idense Webby and Banks, 1976, Clathrodictyon cf. Cl. microundulatum Nestor, 1964, Clathrodictyon cf. Cl. mammillatum (Schmidt, 1858), Clathrodictyon megalamellatum Jeon n. sp., Clathrodictyon plicatum Webby and Banks, 1976, Ecclimadictyon nestori Webby, 1969, Ecclimadictyon undatum Webby and Banks, 1976, Camptodictyon amzassensis (Khalfina, 1960), and Labyrinthodictyon cascum (Webby and Morris, 1976). The clathrodictyid fauna in the Xiazhen Formation is very similar to those from both New South Wales and Tasmania, although the latter two Australian regions do not share any common clathrodictyid species during the Late Ordovician. The paleobiogeographic pattern indicates that the northward drift of South China resulted in a favorable environment for the migration of clathrodictyids from other peri-Gondwanan terranes to South China. In addition, these peri-Gondwanan clathrodictyid species hosted various endobionts, representing a variety of paleoecological interactions. The high abundance and species-level diversity of clathrodictyid species presumably increased the substrate availability of suitable host taxa, judging from the diverse intergrowth associations between clathrodictyids and other benthic organisms. These paleoecological interactions between stromatoporoid and other organisms are known from the Late Ordovician and became more abundant and widespread in the Siluro–Devonian. Overall, the Late Ordovician clathrodictyid assemblage in South China demonstrates one of the highest species-level diversities among all peri-Gondwanan terranes and represents a precursor of the complex, clathrodictyid-dominated communities of later metazoan reefs during the Great Ordovician Biodiversification Event.

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A diverse labechiid stromatoporoid assemblage that includes 16 species in 8 genera was found in the Upper Ordovician Xiazhen Formation (mid–late Katian) at Zhuzhai, Jiangxi Province of South China. The assemblage is characterized by a combination of (1) North China provincial species succeeding from their origination in the Darriwilian, including Pseudostylodictyon poshanense Ozaki, 1938, Labechia shanhsiensis Yabe and Sugiyama, 1930, Labechia variabilis Yabe and Sugiyama, 1930, and Labechiella regularis (Yabe and Sugiyama, 1930) and (2) South China endemic species, including three new species (Labechia zhuzhainus Jeon n. sp., Labechiella beluatus Jeon n. sp., Sinabeatricea luteolus Jeon n. gen. n. sp.), and four species in open nomenclature (Rosenella sp., Cystostroma sp., Pseudostylodictyon sp., and Labechia sp.). The finding of Labechiella gondwanense Jeon n. sp., Stylostroma bubsense Webby, 1991, Stylostroma ugbrookense Webby, 1991, and Thamnobeatricea gouldi Webby, 1991 in the formation indicates that Tasmania was closely related to South China and had a closer paleobiogeographical relation with peri-Gondwanan terranes than with Laurentia. In addition, the occurrences of Labechia altunensis Dong and Wang, 1984 and Stylostroma species support a close biogeographic link between Tarim and South China through the Middle to Late Ordovician interval, corresponding with the results from other fossil groups such as brachiopods, conodonts and chitinozoans. The diverse labechiids from the Xiazhen Formation improve our understanding of the diversity of Ordovician stromatoporoids in peri-Gondwanan terranes and the biogeographic affinities among Australia (especially Tasmania), Tarim, and South China.

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The Lochkovian (Lower Devonian) conodont biostratigraphy in China is poorly known, and conodont-based subdivision schemes for the Lochkovian in peri-Gondwana (the Spanish Central Pyrenees, the Prague Synform, Sardinia, and the Carnic Alps) have not been tested in China. Therefore, we studied conodonts from the lower part (Bed 9 to Bed 13) of the Shanjiang Formation at the Alengchu section of Lijiang, western Yunnan to test the application of established subdivision schemes. The conodont fauna is assignable to 12 taxa belonging to eight genera (Ancyrodelloides, Flajsella, Lanea, Wurmiella, Zieglerodina, Caudicriodus, Pelekysgnathus, and Pseudooneotodus), and enables recognition of two chronostratigraphical intervals from the lower part of the Shanjiang Formation. The interval ranging from the uppermost part of Bed 9 to the upper part of Bed 10 belongs to the lower Lochkovian; whereas an interval covering the uppermost part of Bed 11 to the upper part of Bed 13 is correlated with the upper half of the middle Lochkovian. The Silurian-Devonian boundary is probably located within Bed 9, in the basal part of the Shanjiang Formation. However, the scarcity of specimens precludes definitive identification of bases of the lower, middle, and upper Lochkovian as well as other conodont zones recognized in peri-Gondwana.

The earliest known interpreted spatial competition between two species of stromatoporoids, Clathrodictyon cf. C. mammillatum (Schmidt, 1858) and Labechia sp. is found in the Upper Ordovician Xiazhen Formation at Zhuzhai, South China. The interaction between these taxa was initiated by settlement of Labechia sp. on the surface of Clathrodictyon cf. C. mammillatum. Distortions of the intraskeletal elements of stromatoporoids represented by abnormally large, wide cysts and thick cyst plates in Labechia sp. are observed, along with zigzag crumpled distorted laminae and antagonistic behavior of the skeleton in Clathrodictyon cf. C. mammillatum, indicating syn-vivo interactions. The growth of Labechia sp. was terminated by the overgrowth of Clathrodictyon cf. C. mammillatum, possibly reflecting the ecological superiority of Clathrodictyon cf. C. mammillatum over Labechia sp. The observations are interpreted as competitive interaction between stromatoporoids that was most likely facultative, thus most likely occurring by chance, but the interaction allows assessment of different growth behaviors of the stromatoporoid species. Analysis of the interaction provides evidence to improve understanding of the paleoecology and growth behaviors of early stromatoporoids.

Based on multivariate morphometric analysis, Halysites catenularius is identified from the Rumba Formation (Telychian) and Jaagarahu Formation (Sheinwoodian) of Estonia; H. priscus is confirmed as a junior synonym. Halysites catenularius, H. junior, and H. senior are shown to be closely related; H. catenularius is morphologically intermediate. Cyclomorphism in H. catenularius, recorded by fluctuations of corallite tabularial area, indicates an average annual growth rate of 6.0 mm, which is typical for halysitids. Tubules in H. catenularius, generated from small intramural openings between adjacent corallites, were involved in two types of interstitial increase. The intramural openings, three types of lateral increase, temporary agglutinated patches of corallites, and axial increase documented in H. catenularius resemble features in some species of Catenipora. These similarities are consistent with the interpretation that Halysites evolved from Catenipora. Evaluation of the possibility that both genera are polyphyletic will require further detailed analysis of additional species.

To obtain a fine-grained Mg matrix, the (submicron + micron) bimodal size SiC particle reinforced AZ91 (SiCp/AZ91) composite was subjected to forging followed by the extrusion process first. Then, the fine-grained bimodal size SiCp/AZ91 composite was compressed at 270–370 °C with 0.1–0.001 s−1. The result indicated that the refinement of the Mg matrix contributed to its deteriorated strength at high temperature. However, the grain size is not the only factor influencing flow stress but the SiCp also plays an important role. The effect of SiCp on the fine grained Mg matrix depends on grain size and dislocation density, both of which strongly depend on temperature and strain rate. As compared with the fine grained Mg matrix reinforced by single size SiCp, the one with bimodal size SiCp unusually exhibit lower flow stress during hot compression. The calculated activation energy of the bimodal size SiCp/AZ91 composite is higher than the micron SiCp/AZ91 composite; however, nearly the same as the submicron SiCp/AZ91 composite, and the deformation of which was thought to be controlled by ∼1 vol% submicron SiCp.

Many shorebird populations are in decline along the East Asian-Australasian Flyway. The rapid loss of coastal wetlands in the Yellow Sea, which provide critical stop-over sites during migration, is believed to be the cause of the alarming trends. The Yalu Jiang coastal wetland, a protected area in the north Yellow Sea, supports the largest known migratory staging populations of Bar-tailed Godwits Limosa lapponica (menzbieri and baueri subspecies) and Great Knots Calidris tenuirostris. Monitoring of the macrozoobenthos food for these shorebirds from 2011 to 2016 showed declines of over 99% in the densities of the bivalve Potamocorbula laevis, the major food here for both Bar-tailed Godwits and Great Knots. The loss of the bivalve might be caused by any combination of, but not limited to: (1) change in hydrological conditions and sediment composition due to nearby port construction, (2) run-off of agrochemicals from the extensive shoreline sea cucumber farms, and (3) parasitic infection. Surprisingly, the numbers of birds using the Yalu Jiang coastal wetland remained stable during the study period, except for the subspecies of Bar-tailed Godwit L. l. menzbieri, which exhibited a 91% decline in peak numbers. The lack of an overall decline in the number of bird days in Great Knots and in the peak numbers of L. l. baueri, also given the published simultaneous decreases in their annual survival, implies a lack of alternative habitats that birds could relocate to. This study highlights that food declines at staging sites could be an overlooked but important factor causing population declines of shorebirds along the Flyway. Maintaining the quality of protected staging sites is as important in shorebird conservation as is the safeguarding of staging sites from land claim. Meanwhile, it calls for immediate action to restore the food base for these beleaguered migrant shorebirds at Yalu Jiang coastal wetland.

A new ternary compound Al5NdNi2 was prepared by melting a stoichiometric mixture of aluminum, neodymium, and nickel in an arc furnace and annealing in vacuum. The crystal structure of Al5NdNi2 was studied by X-ray powder diffraction technique and Rietveld analysis. All diffraction lines of Al5NdNi2 were indexed, and the lattice parameters were refined with an orthorhombic structure type of space group Immm (No.71) using Rietveld analysis program DBWS-9807. The lattice parameters are presented, a = 7.0508(1) Å, b = 9.5690(1) Å, c = 3.9792(1) Å, V = 268.47 Å3, Z = 2, ρ = 4.91 g cm−3, and RIR = 1.23.

There have been great efforts on the development of higher-order numerical schemes for compressible Euler equations in recent decades. The traditional test cases proposed thirty years ago mostly target on the strong shock interactions, which may not be adequate enough for evaluating the performance of current higher-order schemes. In order to set up a higher standard for the development of new algorithms, in this paper we present a few benchmark cases with severe and complicated wave structures and interactions, which can be used to clearly distinguish different kinds of higher-order schemes. All tests are selected so that the numerical settings are very simple and any higher order scheme can be straightforwardly applied to these cases. The examples include highly oscillatory solutions and the large density ratio problem in one dimensional case. In two dimensions, the cases include hurricane-like solutions; interactions of planar contact discontinuities with asymptotic large Mach number (the composite of entropy wave and vortex sheets); interaction of planar rarefaction waves with transition from continuous flows to the presence of shocks; and other types of interactions of two-dimensional planar waves. To get good performance on all these cases may push algorithm developer to seek for new methodology in the design of higher-order schemes, and improve the robustness and accuracy of higher-order schemes to a new level of standard. In order to give reference solutions, the fourth-order gas-kinetic scheme (GKS) will be used to all these benchmark cases, even though the GKS solutions may not be very accurate in some cases. The main purpose of this paper is to recommend other CFD researchers to try these cases as well, and promote further development of higher-order schemes.

With the use of temporal derivative of flux function, a two-stage temporal discretization has been recently proposed in the design of fourth-order schemes based on the generalized Riemann problem (GRP) [21] and gas-kinetic scheme (GKS) [28]. In this paper, the fourth-order gas-kinetic scheme will be extended to solve the compressible multicomponent flow equations, where the two-stage temporal discretization and fifth-order WENO reconstruction will be used in the construction of the scheme. Based on the simplified two-species BGK model [41], the coupled Euler equations for individual species will be solved. Each component has its individual gas distribution function and the equilibrium states for each component are coupled by the physical requirements of total momentum and energy conservation in particle collisions. The second-order flux function is used to achieve the fourth-order temporal accuracy, and the robustness is as good as the second-order schemes. At the same time, the source terms, such as the gravitational force and the chemical reaction, will be explicitly included in the two-stage temporal discretization through their temporal derivatives. Many numerical tests from the shock-bubble interaction to ZND detonative waves are presented to validate the current approach.

Protected areas, including nature reserves and management areas, are established for the conservation of biological diversity and protection of the associated natural and cultural resources. These objectives, however, are often in conflict with socio-economic development. We investigated the plant communities dominated by the dove tree Davidia involucrata in a nature reserve on Mount Jinfo, China, where people intensively manage large areas of bamboo stands. We found a significant lack of small-sized main stems of D. involucrata (0–25 cm diameter at breast height; height > 1.3 m) and newly emerging sprouts in the reserve. The height-class distribution showed a unimodal pattern, with most individuals (of both D. involucrata and co-occurring species) concentrated in the 16–28 m height-class, and few individuals in the shrub and sub-canopy layer (1.3–8 m). Existing practices to facilitate the spread of bamboo stands, and the need to develop a local market for bamboo shoots received little consideration when the nature reserve was established in 1979 to protect D. involucrata. To conserve D. involucrata on Mount Jinfo the appropriate authorities and local parties involved in bamboo harvesting need to focus on methods that are favourable to the life history of this and other tree species, and strategies for their regeneration. These methods will also benefit the conservation of other highly valued trees that share similar life-history characteristics with D. involucrata.

The new ternary compound of Al2Cu3Gd was prepared by melting with stoichiometric composition in an electric arc furnace. The X-ray powder diffraction data of Al2Cu3Gd have been collected by the Rigaku Smart Lab X-ray powder diffractometer. The Rietveld refinement method had been used to study the crystal structure of Al2Cu3Gd. The results showed that the Al2Cu3Gd, new compound have the hexagonal structure, space group P6/mmm (No. 191) with a = 5.1822 (1) Å, c = 4.1566 (1) Å, V = 96.67 Å3, Z = 1, and the density is 6.62 g cm−3, and the intensity ratio reference intensity ratio is 1.29.

Right pulmonary artery–left atrial fistula is a rare congenitalcardiac anomaly, and only a few articles published so far have reported the diagnosis and treatment of right pulmonary artery–left atrial fistula. In this study, we report three cases of successful transcatheter closure or surgical repair of right pulmonary artery–left atrial fistula.

The hot deformation behavior of as-cast AZ91 magnesium alloy reinforced by SiC nanoparticles (SiCp/AZ91 nanocomposite) was investigated using hot compression test. Compared with unreinforced AZ91 alloy, peak stress of the SiCp/AZ91 nanocomposite achieved faster and high temperature deformation ability which was enhanced by the addition of SiC nanoparticles. The values of n for the AZ91 alloy and nanocomposite were 6.9 and 4.6, while the values of Q were 207.96 kJ/mol and 184.6 kJ/mol, respectively. The processing map showed the optimum processing conditions for the nanocomposite mainly concentrated at 523–673 K/0.018–0.001 s−1 and the maximum power dissipation efficiency was found to be 36% at a temperature of 673 K and the strain rate of 0.001 s−1. Based on the constitutive equation and processing map, the deformation mechanism for the present nanocomposite should be dominated by the mechanism of dynamic recrystalization.

Catenipora is one of the most common tabulate coral genera occurring in various lithofacies in the Upper Ordovician Xiazhen Formation at Zhuzhai in South China. A combination of traditional multivariate analysis and geometric morphometrics is applied to a large number of specimens to distinguish and identify species. Based on three major principal components extracted from 11 morphological characters, three major groups as determined by the cluster-analysis dendrogram are considered to be morphospecies. Their validity and distinctiveness are confirmed by discriminant analysis, descriptive statistics, and bivariate plots. Tabularium area and common wall thickness are the most meaningful characters to distinguish the three morphospecies. Geometric morphometrics is adopted to compare the morphospecies with types and/or figured specimens of species previously reported from the vicinity of Zhuzhai. Despite discrepancies in corallite size, principal component analysis and discriminant analysis, as well as consideration of overall morphological characteristics, indicate that the morphospecies represent C. zhejiangensis Yu in Yu et al., 1963, C. shiyangensis Lin and Chow, 1977, and C. dianbiancunensis Lin and Chow, 1977.

Catenipora occurs in seven stratigraphic intervals in the Xiazhen Formation at Zhuzhai, representing a variety of heterogeneous environments. The coralla preservation is variable due to differential compaction; coralla preserved in limestones are commonly intact and in growth position, whereas those in shales are mostly crushed or fragmentary. The size and shape of corallites are considered primarily to be species-specific characters, but are also related to the depositional environments. In all species, morphological characters, including corallite size, septal development, and shape and size of lacunae, show high variability in accordance with lithofacies and stratigraphic position. The intraspecific differences in corallite size at various localities in the Zhuzhai area may indicate responses to local environmental factors, but may also reflect genetic differences if there was limited connection among populations.

In this paper, a compact third-order gas-kinetic scheme is proposed for the compressible Euler and Navier-Stokes equations. The main reason for the feasibility to develop such a high-order scheme with compact stencil, which involves only neighboring cells, is due to the use of a high-order gas evolution model. Besides the evaluation of the time-dependent flux function across a cell interface, the high-order gas evolution model also provides an accurate time-dependent solution of the flow variables at a cell interface. Therefore, the current scheme not only updates the cell averaged conservative flow variables inside each control volume, but also tracks the flow variables at the cell interface at the next time level. As a result, with both cell averaged and cell interface values, the high-order reconstruction in the current scheme can be done compactly. Different from using a weak formulation for high-order accuracy in the Discontinuous Galerkin method, the current scheme is based on the strong solution, where the flow evolution starting from a piecewise discontinuous high-order initial data is precisely followed. The cell interface time-dependent flow variables can be used for the initial data reconstruction at the beginning of next time step. Even with compact stencil, the current scheme has third-order accuracy in the smooth flow regions, and has favorable shock capturing property in the discontinuous regions. It can be faithfully used from the incompressible limit to the hypersonic flow computations, and many test cases are used to validate the current scheme. In comparison with many other high-order schemes, the current method avoids the use of Gaussian points for the flux evaluation along the cell interface and the multi-stage Runge-Kutta time stepping technique. Due to its multidimensional property of including both derivatives of flow variables in the normal and tangential directions of a cell interface, the viscous flow solution, especially those with vortex structure, can be accurately captured. With the same stencil of a second order scheme, numerical tests demonstrate that the current scheme is as robust as well-developed second-order shock capturing schemes, but provides more accurate numerical solutions than the second order counterparts.

The decomposition mechanism of block copolymer templates inside as-synthesized mesostructured solids has been systematically studied using solid-state 1H magic angle spinning nuclear magnetic resonance spectroscopy, thermogravimetric analysis, and high-vacuum Fourier transform infrared spectrometry. It is shown that there exists hydrogen-bonding interaction between silanols and block copolymers at the inorganic–organic interface in the self-assembled as-synthesized mesostructured solids, which plays an important role in protecting the surfactants against decomposition during the high-temperature hydrothermal treatment process. Increasing silanol concentration can enhance the hydrogen-bonding interaction and thus shows better “protection” effect. Moreover, the thermal decomposition of the block copolymer in as-synthesized mesostructured solids in air commences at higher temperatures compared with that in acidic solution or in air, providing further evidence in support of the silanol protection mechanism.