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| 1 | Processing,Microstructures,and Mechanical Properties of Magnesium Matrix Composites:A Review显示文摘In the last two decades, light-weight magnesium matrix composites have been the hot issue of material field due to their excellent mechanical and physical properties, e.g., high-specific strength and modulus, good wear resistance, and damping capacity. As compared with aluminum matrix composites, magnesium matrix composites have merit in their specific weight and have wide applications in aerospace and aeronautical fields. Generally, the processing techniques for magnesium matrix composites can be categorized as conventional and special processing routes. In recent years, as a special processing route, metal melt infiltration into porous ceramic preform featured by its low cost and availability of high-volume fraction of reinforced ceramics have been receiving much attention. Thus, in this review, one emphasis was put on the description of this processing technique in association with the means to obtain good wettability, the prerequisite for this kind of processing method. Based on the recognized fact that there exist clean interface and bonding ability between ceramics and matrix metal, in-situ reaction synthesis is usually utilized to fabricate magnesium matrix composites.Therefore, the interfacial feature was also reviewed for the in-situ reaction synthesis. Characterizations of microstructures and various mechanical–physical properties were finally summarized for magnesium matrix composites including tensile response, wear resistance, creep behavior, and damping capacity. | Liqing Chen Yantao Yao | 2014 | Acta Metallurgica Sinica(English Letters)2014,27,5: | 15 |
| 2 | Carbon pools and fluxes in the China Seas and adjacent oceans显示文摘The China Seas include the South China Sea, East China Sea, Yellow Sea, and Bohai Sea. Located off the Northwestern Pacific margin, covering 4700000 km^2 from tropical to northern temperate zones, and including a variety of continental margins/basins and depths, the China Seas provide typical cases for carbon budget studies. The South China Sea being a deep basin and part of the Western Pacific Warm Pool is characterized by oceanic features; the East China Sea with a wide continental shelf, enormous terrestrial discharges and open margins to the West Pacific, is featured by strong cross-shelf materials transport; the Yellow Sea is featured by the confluence of cold and warm waters; and the Bohai Sea is a shallow semiclosed gulf with strong impacts of human activities. Three large rivers, the Yangtze River, Yellow River, and Pearl River, flow into the East China Sea, the Bohai Sea, and the South China Sea, respectively. The Kuroshio Current at the outer margin of the Chinese continental shelf is one of the two major western boundary currents of the world oceans and its strength and position directly affect the regional climate of China. These characteristics make the China Seas a typical case of marginal seas to study carbon storage and fluxes. This paper systematically analyzes the literature data on the carbon pools and fluxes of the Bohai Sea,Yellow Sea, East China Sea, and South China Sea, including different interfaces(land-sea, sea-air, sediment-water, and marginal sea-open ocean) and different ecosystems(mangroves, wetland, seagrass beds, macroalgae mariculture, coral reefs, euphotic zones, and water column). Among the four seas, the Bohai Sea and South China Sea are acting as CO_2 sources, releasing about0.22 and 13.86–33.60 Tg C yr^(-1) into the atmosphere, respectively, whereas the Yellow Sea and East China Sea are acting as carbon sinks, absorbing about 1.15 and 6.92–23.30 Tg C yr^(-1) of atmospheric CO_2, respectively. Overall, if only the CO_2 exchange at the sea-air interface is considered, the Chinese marginal seas appear to be a source of atmospheric CO_2, with a net release of 6.01–9.33 Tg C yr^(-1), mainly from the inputs of rivers and adjacent oceans. The riverine dissolved inorganic carbon (DIC) input into the Bohai Sea and Yellow Sea, East China Sea, and South China Sea are 5.04, 14.60, and 40.14 Tg C yr^(-1),respectively. The DIC input from adjacent oceans is as high as 144.81 Tg C yr^(-1), significantly exceeding the carbon released from the seas to the atmosphere. In terms of output, the depositional fluxes of organic carbon in the Bohai Sea, Yellow Sea, East China Sea, and South China Sea are 2.00, 3.60, 7.40, and 5.92 Tg C yr^(-1), respectively. The fluxes of organic carbon from the East China Sea and South China Sea to the adjacent oceans are 15.25–36.70 and 43.93 Tg C yr^(-1), respectively. The annual carbon storage of mangroves, wetlands, and seagrass in Chinese coastal waters is 0.36–1.75 Tg C yr^(-1), with a dissolved organic carbon(DOC) output from seagrass beds of up to 0.59 Tg C yr^(-1). Removable organic carbon flux by Chinese macroalgae mariculture account for 0.68 Tg C yr^(-1) and the associated POC depositional and DOC releasing fluxes are 0.14 and 0.82 Tg C yr^(-1), respectively. Thus, in total, the annual output of organic carbon, which is mainly DOC, in the China Seas is 81.72–104.56 Tg C yr^(-1). The DOC efflux from the East China Sea to the adjacent oceans is 15.00–35.00 Tg C yr^(-1). The DOC efflux from the South China Sea is 31.39 Tg C yr^(-1). Although the marginal China Seas seem to be a source of atmospheric CO_2 based on the CO_2 flux at the sea-air interface, the combined effects of the riverine input in the area, oceanic input, depositional export,and microbial carbon pump(DOC conversion and output) indicate that the China Seas represent an important carbon storage area. | Nianzhi JIAO Yantao LIANG Yongyu ZHANG Jihua LIU Yao ZHANG Rui ZHANG Meixun ZHAO Minhan DAI Weidong ZHAI Kunshan GAO Jinming SONG Dongliang YUAN Chao LI Guanghui LIN Xiaoping HUANG Hongqiang YAN Limin HU Zenghu ZHANG Long WANG Chunjie CAO Yawei LUO Tingwei LUO Nannan WANG Hongyue DANG Dongxiao WANG Si ZHANG | 2018 | Science China Earth Sciences2018,61,11: | 12 |
| 3 | Processing of B_4C Particulate-reinforced Magnesium-matrix Composites by Metal-assisted Melt Infiltration Technique显示文摘In fabricating magnesium-matrix composites,an easy and cost-effective route is to infiltrate the ceramic preform with molten Mg without any external pressure.However,a rather well wettability of molten Mg with ceramic reinforcement is needed for this process.In order to improve the wettability of the metal melt with ceramic preform during fabricating composites by metal melt infiltration,a simple and viable method has been proposed in this paper where a small amount of metal powder with higher melting point is added to the ceramic preform such that the surface tension of the Mg melt and the liquid-solid interfacial tension could be reduced.By using this method,boron carbide particulate-reinforced magnesium-matrix composites(B4C/Mg)have been successfully fabricated where Ti powder immiscible with magnesium melt was introduced into B4 C preform as infiltration inducer.The infiltration ability of molten Mg to the ceramic preform was further studied in association with the processing conditions and the mechanism involved in this process was also analyzed. | Yantao Yao Liqing Chen | 2014 | Journal of Materials Science & Technology2014,30,7: | 11 |
| 4 | Numerical Simulation for Shallow Strata Stability of Coral Reef in the Southwest of Yongshu Reef(South China Sea)显示文摘In recent years, infrastructure construction on coral reefs has been increasingly developed. Therefore, the shallow strata stability of coral reefs in the South China Sea should be evaluated. This study aims to investigate the profiles for the shallow strata of coral reefs in the southwest of the Yongshu Reef, particularly in the hydrodynamic marine environment, and to establish a geological model for numerical simulation using Geo-Studio. The shallow strata of the coral reefs include mass gravel, sand gravel, mid-coarse sand, silty sand, fine sand, and reef limestone. The shallow reef slope near the lagoon is similar to a ‘layer cake', in which the side close to the sea is analogous to a ‘block cake'. The simulation results showed that coral reef stability depends on wave loads and earthquake strength and on the physical properties of coral reefs. The factor of safety for the outer reef is greater than 10.0 under static, wave, and seismic conditions; this indicated that the outer reefs were less affected by waves and earthquakes. However, the factor of safety next to the lagoon varied from 0.1 to 5.3. The variation was primarily caused by the thick strata of coral reefs close to the sea(reef limestone, typically with the thickness > 10 m and equivalent to a block). The soil and rock layers in the coral reef strata with thicknesses < 10 m showed weak engineering geological characteristics. Our findings can provide useful information to future construction projects on coral reefs. | TANG Qinqin ZHANG Jinchang FENG Yingci LI Jian YAO Yantao SUN Jie ZHAN Wenhuan | 2018 | Journal of Ocean University of China2018,17,4: | 3 |
| 5 | High-temperature Oxidation Behavior of a High Manganese Austenitic Steel Fe–25Mn–3Cr–3Al–0.3C–0.01N显示文摘In this paper, a Fe–Mn–Al–C austenitic steel with certain addition of Cr and N alloy was used as experimental material. By using the SETSYS Evolution synchronous differential thermal analysis apparatus, the scanning electron microscope(SEM), the electron microprobe(EPMA) and the X-ray diffraction(XRD), the high-temperature oxidation behavior microstructure and the phase compositions of this steel in air at 600–1,000 °C for 8 h have been studied. The results show that in the whole oxidation temperature range, there are three distinct stages in the mass gain curves at temperature higher than 800 °C and the oxidation process can be divided into two stages at temperature lower than 800 °C.At the earlier stage the gain rate of the weight oxidized in temperature range of 850 °C to 1,000 °C are extremely lower.The oxidation products having different surface microstructures and phase compositions were produced in oxidation reaction at different temperatures. The phase compositions of oxide scale formed at 1,000 °C are composed of Fe and Mn oxide without Cr. However, protective film of Cr oxide with complicated structure can be formed when the oxidation temperature is lower than 800 °C. | Xiaoyun Yuan Yantao Yao Liqing Chen | 2014 | Acta Metallurgica Sinica(English Letters)2014,27,3: | 3 |
| 6 | Emerged fossil corals on the coast of northwestern Hainan Island, China: Implications for mid-Holocene sea level change and tectonic uplift显示文摘Fossil corals are widespread on the coast of northwestern Hainan Island, China. Most of these corals are exposed during low tide levels, indicating that a higher sea level may have existed during their life time. The radiocarbon data introduced by this paper in combination with those from other sources show that the corals were alive mainly during the midto late-Holocene. Mid-Holocene sea levels 1-3 m higher than the present level were confirmed for adjacent coasts; however, the emerged corals on the investigated coast are not necessarily indicators of a higher eustatic sea level. They do predict relative sea levels of 1.5-3.4 m when using 1 m below the tidal datum as the upper limit of coral growth. However, using the Mean Lower Low Water as the coral's upper growth limit, the relative sea level on the non-volcanic coast was almost as high as the present level, whereas that on the volcanic coast was 0.4-2.0 m higher than present. Therefore, the exposure of these dead coral heads and their discrepancy in elevation may be the result of tectonic uplift caused by volcanic activities. From these results, the highest sea level of upward coral growth must be defined first when using fossil corals to reconstruct past sea levels. Meanwhile, vertical tectonics have to be taken into account as a significant factor when conducting high-resolution sea level reconstruction, although the South China coast is located in a 'tectonically stable' region. | YAO YanTao ZHAN WenHuan SUN JinLong SUN Jie | 2013 | Chinese Science Bulletin2013,58,23: | 2 |
| 7 | Crustal activities recorded incoral reefs in the northwestern South China Sea显示文摘Coral reefs in the northwest of South China Sea have recorded the information from not only the environmental variation but also the crustal activities there during their development. The main crustal activities correlated with the coral reef development include fault, seismic, and volcano activities, etc. The high-resolution spark seismic profiles in the northwestern South China Sea show that the fault activities in the coral reef region have been clearly recorded, and appear as neonatal faults incising reefs. Earthquakes in the coral reef region are rather intense, especially the two occurring on December, 31, 1994, and January, 10, 1995, around the southwest of Leizhou Peninsula, with the magnitude of 6.1 and 6.2, respectively. They have great influence on the growth of the local coral reefs. Quaternary volcanos are active in the northwestern South China Sea, especially around the southwest of Leizhou Peninsula, and they have obvious control of the coral reef development. Some submarine volcanoes form the substrates of coral reef, while a few emerge above the sea surface and form coral islands. | ZHAN Wenhuan YAO Yantao ZHANG Zhiqiang SUN Zongxun ZHAN Meizhen SUN Longtao LIU Zaifeng | 2006 | Chinese Science Bulletin2006,51,B12: | 1 |
| 8 | The influence of earthquakes on Zhubi Reef in the Nansha Islands of the South China Sea显示文摘It is exceedingly important to estimate the stability of coral reefs. In recent years, growing construction projects have been carried out on the reef flat in the South China Sea. As a special marine geotechnical medium, it is made of the reef debris underwent overwhelmingly long geological age. Reefs grow thickly on the carbonate platform after the Late Oligocene and have five to six main sedimentary facies. It can be used as a recorder to measure the occurrence time of recent earthquake. A model of reef body is presented to study the influence of earthquakes according to the geological structure characteristic of reefs in the Nansha Islands. Furthermore, Geo Studio is used to simulate stress and deformation situations within it under various earthquake intensities. A safety factor is calculated by the limit equilibrium method, and the possible scenarios of earthquake-induced landslides and sliding scale are defined with a Newmark sliding block method, as well as stress distribution and deformation behaviors. Therefore, the numerical results suggest that the connections between the coral reef and the earthquake are as follows:(1) the reef body has a good stability under self-gravity state;(2) after the earthquake, it may cause slope's instability and bring out slumping when the safety factor is smaller than 1(FS<1);(3) the safety factor decreases with the increasing earthquake intensity, and fluctuates around a particular value after a while;and(4) as a new developed part of the reef, the smaller shallow landslide will be easily subject to collapse caused by the earthquake. It is concluded that it is feasible to provide a reference for evaluating the stability of coral reef using a geotechnical engineering simulation method. This can help the engineering constructions in the South China Sea. | GUO Lei ZHAN Wenhuan ZHANG Fan ZHANG Jinchang YAO Yantao LI Jian FENG Yingci CHEN Mei CHENG Gong | 2017 | Acta Oceanologica Sinica2017,36,3: | 1 |
| 9 | H3‑T6SS of Pseudomonas aeruginosa PA14 contributes to environmental adaptation via secretion of a biofilm‑promoting effector显示文摘Microbial species often occur in complex communities and exhibit intricate synergistic and antagonistic interactions.To avoid predation and compete for favorable niches,bacteria have evolved specialized protein secretion systems.The type VI secretion system(T6SS)is a versatile secretion system widely distributed among Gram-negative bacteria that translocates effectors into target cells or the extracellular milieu via various physiological processes.Pseudomonas aeruginosa is an opportunistic pathogen responsible for many diseases,and it has three independent T6SSs(H1-,H2-,and H3-T6SS).In this study,we found that the H3-T6SS of highly virulent P.aeruginosa PA14 is negatively regulated by OxyR and OmpR,which are global regulatory proteins of bacterial oxidative and acid stress.In addition,we identified a H3-T6SS effector PA14_33970,which is located upstream of VgrG3.PA14_33970 interacted directly with VgrG3 and translocated into host cells.Moreover,we found that H3-T6SS and PA14_33970 play crucial roles in oxidative,acid,and osmotic stress resistance,as well as in motility and biofilm formation.PA14_33970 was identified as a new T6SS effec-tor promoting biofilm formation and thus named TepB.Furthermore,we found that TepB contributes to the virulence of P.aeruginosa PA14 toward Caenorhabditis elegans.Overall,our study indicates that H3-T6SS and its biofilm-promot-ing effector TepB are regulated by OxyR and OmpR,both of which are important for adaptation of P.aeruginosa PA14 to multiple stressors,providing insights into the regulatory mechanisms and roles of T6SSs in P.aeruginosa. | Yantao Yang Damin Pan Yanan Tang Jiali Li Kaixiang Zhu Zonglan Yu Lingfang Zhu Yao Wang Peng Chen Changfu Li | 2022 | Stress Biology2022,2,1: | 0 |
| 10 | The effect of iron on the preservation of organic carbon in marine sediments and its implications for carbon sequestration显示文摘Marine sediments are the most significant reservoir of organic carbon(OC)in Earth′s surface system.Iron,a crucial component of the marine biogeochemical cycle,has a considerable impact on marine ecology and carbon cycling.Understanding the effect of iron on the preservation of OC in marine sediments is essential for comprehending biogeochemical processes of carbon and climate change.This review summarizes the methods for characterizing the content and structure of iron-bound OC and explores the influencing mechanism of iron on OC preservation in marine sediments from two aspects:the selective preservation of OC by reactive iron minerals(iron oxides and iron sulfides)and iron redox processes.The selective preservation of sedimentary OC is influenced by different types of reactive iron minerals,OC reactivity,and functional groups.The iron redox process has dual effects on the preservation and degradation of OC.By considering sedimentary records of iron-bound OC across diverse marine environments,the role of iron in long-term preservation of OC and its significance for carbon sequestration are illustrated.Future research should focus on identifying effective methods for extracting reactive iron,the effect of diverse functional groups and marine sedimentary environments on the selective preservation of OC,and the mediation of microorganisms.Such work will help elucidate the influencing mechanisms of iron on the long-term burial and preservation of OC and explore its potential application in marine carbon sequestration to maximize its role in achieving carbon neutrality. | Limin HU Yuhan JI Bin ZHAO Xiting LIU Jiazong DU Yantao LIANG Peng YAO | 2023 | Science China Earth Sciences2023,66,9: | 0 |