The rapid cooling of a metallic liquid(ML)results in short-range order(SRO)among the atomic arrangements and a disordered structure in the resulting metallic glass(MG).These phenomena cause various possible features i...The rapid cooling of a metallic liquid(ML)results in short-range order(SRO)among the atomic arrangements and a disordered structure in the resulting metallic glass(MG).These phenomena cause various possible features in the microscopic structure of the MG,presenting a puzzle about the nature of the MGs’microscopic structure beyond SRO.In this study,the nanoscale density gradient(NDG)originating from a sequential arrangement of clusters with different atomic packing densities(APDs),representing the medium-range structural heterogeneity in Zr_(60)Cu_(30)Al_(10)MG,was characterized using electron tomography(ET)combined with image simulations based on structure modeling.The coarse polyhedrons with distinct facets identified in the three-dimensional images coincide with icosahedron-like clusters and represent the spatial positions of clusters with high APDs.Rearrangements of the different clusters according to descending APD order in the glass-forming process are responsible for the NDG that stabilizes both the supercooled ML and the amorphous states and acts as a hidden rule in the transition from ML to MG.展开更多
The West Pacific Ocean is considered as the provenance center of global marine life and has the highest species diversity of numerous marine taxa.The phytoplankton,as the primary producer at the base of the food chain...The West Pacific Ocean is considered as the provenance center of global marine life and has the highest species diversity of numerous marine taxa.The phytoplankton,as the primary producer at the base of the food chain,effects on climate change,fish resources as well as the entire ecosystem.However,there are few large-scale surveys covering several currents with different hydrographic characteristics.This study aimed to explore the relationships between the spatio-temporal variation in phytoplankton community structure and different water masses.A total of 630 water samples and 90 net samples of phytoplankton were collected at 45 stations in the Northwest Pacific Ocean(21.0°–42.0°N,118.0°–156.0°E)during spring and summer 2017.A total of 281 phytoplankton taxa(>5μm)belonging to 61 genera were identified in the study area.The distribution pattern of the phytoplankton community differed significantly both spatially and temporally.The average abundances of phytoplankton in spring and summer were 797.07×10~2 cells/L and 84.94×10~2 cells/L,respectively.Whether in spring or summer,the maximum abundance always appeared in the northern transition region affected by the Oyashio Current,where nutrients were abundant and diatoms dominated the phytoplankton community;whereas the phytoplankton abundance was very low in the oligotrophic Kuroshio region,and the proportion of dinoflagellates in total abundance increased significantly.The horizontal distribution of phytoplankton abundance increased from low to high latitudes,which was consistent with the trend of nutrient distributions,but contrary to that of water temperature and salinity.In the northern area affected by the Oyashio Current,the phytoplankton abundance was mainly concentrated in the upper 30 m of water column,while the maximum abundance often occurred at depths of 50–75 m in the south-central area affected by the Kuroshio Current.Pearson correlation and redundancy analysis(RDA)showed that phytoplankton abundance was significant negatively correlated with temperature and salinity,but positively correlated with nutrient concentration.The phytoplankton community structure was mainly determined by nutrient availability,especially the N:P ratio.展开更多
Medusae in 116 samples collected from the coastal waters of the northern Beibu Gulf during four seasonal oceanographic cruises from October 2017 to August 2018 were analyzed.In total,34 species were identified.Two of ...Medusae in 116 samples collected from the coastal waters of the northern Beibu Gulf during four seasonal oceanographic cruises from October 2017 to August 2018 were analyzed.In total,34 species were identified.Two of the species are new to science,Proboscidactyla pentacanalis Xu,Chen&Yang sp.nov.and Helgicirrha apapillata Xu,Chen&Wang sp.nov.,and three species are newly recorded in the Beibu Gulf,i.e.,Hydractinia vacuolata Xu&Huang,2006,Proboscidactyla flavicirrata Brandnt,1834 and Phialella macrogona Xu,Huang&Wang,1985.Collections of the species were deposited at the Third Institute of Oceanography,Ministry of Natural Resources.展开更多
Carbon nanotube (CNT)/maleic acid anhydride (MAH)-grafted polypropylene (PP) composites were prepared by in situ grafting method. Infrared spectroscopy showed that the CNTs were linked to PP by MAH grafting. The...Carbon nanotube (CNT)/maleic acid anhydride (MAH)-grafted polypropylene (PP) composites were prepared by in situ grafting method. Infrared spectroscopy showed that the CNTs were linked to PP by MAH grafting. The microstructures and calorimetry analysis indicated that the crystallization behaviors of the filled and unfilled PP were quite different. The addition of CNTs dramatically reduced the spherulite size, increased crystallization rate and improved the thermal stability of PP. These results confirmed the expected nucleant effect of CNT on the crystallization of PP. Scanning and transmission electron microscopy showed that the CNTs were dispersed homogeneously, indicating that the original CNT bundles were separated into individual tubes by the grafting.展开更多
Based on the electron dynamic diffraction, phase shift of the exit wave function vs misorientation of the incident electron beam from the exact zone axis has been calculated for the [001] oriented copper. The result s...Based on the electron dynamic diffraction, phase shift of the exit wave function vs misorientation of the incident electron beam from the exact zone axis has been calculated for the [001] oriented copper. The result shows that the peak of phase shift is the maximum at the atom position as the electron beam along the exact [001] zone axis, and the peak value of phase shift decreases as increases of the misorientation. At small misorientation, i.e. less than 5 degree, change of the phase shift is minimal. The peak value of phase shift decreases significantly when the incident beam deviates form the zone axis over 10 degree and the exit wave has a planar configuration as the misoriention angle arrives -17 degree. The effect of this phase shift characteristics on the information extracted from the hologram has also been considered.展开更多
The microstructural features of high-temperature sintered and CaO-MgO-Al_2O_3-SiO_2(CMAS) corroded air plasma sprayed Y_2O_3 stabilized ZrO_2(YSZ) thermal barrier coatings(TBCs) under the thermal gradient condition we...The microstructural features of high-temperature sintered and CaO-MgO-Al_2O_3-SiO_2(CMAS) corroded air plasma sprayed Y_2O_3 stabilized ZrO_2(YSZ) thermal barrier coatings(TBCs) under the thermal gradient condition were comparatively studied. As-sprayed YSZ has a lamellar structure and the lamellae are composed of closely aligned columnar crystals. The sintered and the CMAS corroded YSZ coatings maintain the t'-ZrO_2 phase as the as-sprayed YSZ coating. The sintered YSZ remains the lamellar structure with reduced interlamellar gaps and grains coarsening. After the CMAS corrosion, the top layer of the YSZ coating keeps its lamellar structure consisting of some columnar grains with the CMAS infiltration into the intergrain gaps and the formation of striped Zr_2Y_2 O_7. The typical lamellar structure transforms into more equiaxed grains in the middle and bottom layers of the ceramic coating along with significant infiltration of amorphous CMAS and anorthite formation in the bottom layer owing to the high contents of Ca and Al.展开更多
基金supported by the Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine(ZYYCXTD-C-202006)Gansu Cheezheng Tibetan Medicine(BUCM-2021-JS-FW-087,Beijing,China).
文摘目的:评价白脉软膏在腰椎间盘突出症(lumbar disc herniation)患者中的疗效与安全性。方法:本研究设计了一项前瞻、随机、双盲、安慰剂对照的多中心临床试验方案。计划招募194例患者,按1:1的比例平均分配至试验组和对照组。患者将接受为期14天的白脉软膏或安慰剂的干预,随后进行为期1周的随访。通过视觉模拟评分法(visual analogue scale score)评估疼痛程度,日本骨科协会评估治疗分数(Japanese Orthopedic Association score)评估功能状态,Likert量表将用于评估麻木程度,此外还将记录应急处理的使用和对健康教育的依从情况。安全性评估将包括实验室检查和不良事件记录。讨论:这项试验将首次对白脉软膏在腰椎间盘突出症患者中进行临床疗效和安全性评价。使用安慰剂的优势在于排除因盲法不充分而导致的偏倚。为了避免由研究对象和研究者的主观因素引起的任何偏倚,对于结局评价者、数据管理人员、统计分析人员以及所有相关研究人员都将实施盲法。本试验结果将为腰椎间盘突出症的治疗以及白脉软膏的未来研究方向提供重要依据。
基金supported by the National Natural Science Foundation of China(51971093,52192603,and 51501043)。
文摘The rapid cooling of a metallic liquid(ML)results in short-range order(SRO)among the atomic arrangements and a disordered structure in the resulting metallic glass(MG).These phenomena cause various possible features in the microscopic structure of the MG,presenting a puzzle about the nature of the MGs’microscopic structure beyond SRO.In this study,the nanoscale density gradient(NDG)originating from a sequential arrangement of clusters with different atomic packing densities(APDs),representing the medium-range structural heterogeneity in Zr_(60)Cu_(30)Al_(10)MG,was characterized using electron tomography(ET)combined with image simulations based on structure modeling.The coarse polyhedrons with distinct facets identified in the three-dimensional images coincide with icosahedron-like clusters and represent the spatial positions of clusters with high APDs.Rearrangements of the different clusters according to descending APD order in the glass-forming process are responsible for the NDG that stabilizes both the supercooled ML and the amorphous states and acts as a hidden rule in the transition from ML to MG.
基金The Public Science and Technology Research Funds Projects of Ocean under contract No.201305027the project sponsored by the Scientific Research Foundation of Third Institute of Oceanography,SOA under contract No.2017009。
文摘The West Pacific Ocean is considered as the provenance center of global marine life and has the highest species diversity of numerous marine taxa.The phytoplankton,as the primary producer at the base of the food chain,effects on climate change,fish resources as well as the entire ecosystem.However,there are few large-scale surveys covering several currents with different hydrographic characteristics.This study aimed to explore the relationships between the spatio-temporal variation in phytoplankton community structure and different water masses.A total of 630 water samples and 90 net samples of phytoplankton were collected at 45 stations in the Northwest Pacific Ocean(21.0°–42.0°N,118.0°–156.0°E)during spring and summer 2017.A total of 281 phytoplankton taxa(>5μm)belonging to 61 genera were identified in the study area.The distribution pattern of the phytoplankton community differed significantly both spatially and temporally.The average abundances of phytoplankton in spring and summer were 797.07×10~2 cells/L and 84.94×10~2 cells/L,respectively.Whether in spring or summer,the maximum abundance always appeared in the northern transition region affected by the Oyashio Current,where nutrients were abundant and diatoms dominated the phytoplankton community;whereas the phytoplankton abundance was very low in the oligotrophic Kuroshio region,and the proportion of dinoflagellates in total abundance increased significantly.The horizontal distribution of phytoplankton abundance increased from low to high latitudes,which was consistent with the trend of nutrient distributions,but contrary to that of water temperature and salinity.In the northern area affected by the Oyashio Current,the phytoplankton abundance was mainly concentrated in the upper 30 m of water column,while the maximum abundance often occurred at depths of 50–75 m in the south-central area affected by the Kuroshio Current.Pearson correlation and redundancy analysis(RDA)showed that phytoplankton abundance was significant negatively correlated with temperature and salinity,but positively correlated with nutrient concentration.The phytoplankton community structure was mainly determined by nutrient availability,especially the N:P ratio.
基金The National Natural Science Foundation of China under contract No.41406216the foundation of Third Institute of Oceanography under contract No.2013016the Global Climate Change and Ocean Atmosphere Interaction Research,Biological Classification System Research and the Marine Biological Sample Museum Upgrade and Expansion under contract No.GASI-01-02-04
文摘Medusae in 116 samples collected from the coastal waters of the northern Beibu Gulf during four seasonal oceanographic cruises from October 2017 to August 2018 were analyzed.In total,34 species were identified.Two of the species are new to science,Proboscidactyla pentacanalis Xu,Chen&Yang sp.nov.and Helgicirrha apapillata Xu,Chen&Wang sp.nov.,and three species are newly recorded in the Beibu Gulf,i.e.,Hydractinia vacuolata Xu&Huang,2006,Proboscidactyla flavicirrata Brandnt,1834 and Phialella macrogona Xu,Huang&Wang,1985.Collections of the species were deposited at the Third Institute of Oceanography,Ministry of Natural Resources.
基金supported by the National Natural Science Foundation of China(Nos.50772033,50372020)the Natural Science Fund in Hunan Province,China(No.2007FJ3003).
文摘Carbon nanotube (CNT)/maleic acid anhydride (MAH)-grafted polypropylene (PP) composites were prepared by in situ grafting method. Infrared spectroscopy showed that the CNTs were linked to PP by MAH grafting. The microstructures and calorimetry analysis indicated that the crystallization behaviors of the filled and unfilled PP were quite different. The addition of CNTs dramatically reduced the spherulite size, increased crystallization rate and improved the thermal stability of PP. These results confirmed the expected nucleant effect of CNT on the crystallization of PP. Scanning and transmission electron microscopy showed that the CNTs were dispersed homogeneously, indicating that the original CNT bundles were separated into individual tubes by the grafting.
基金financially supported tional Natural Science Foundation of China No. 60271028.
文摘Based on the electron dynamic diffraction, phase shift of the exit wave function vs misorientation of the incident electron beam from the exact zone axis has been calculated for the [001] oriented copper. The result shows that the peak of phase shift is the maximum at the atom position as the electron beam along the exact [001] zone axis, and the peak value of phase shift decreases as increases of the misorientation. At small misorientation, i.e. less than 5 degree, change of the phase shift is minimal. The peak value of phase shift decreases significantly when the incident beam deviates form the zone axis over 10 degree and the exit wave has a planar configuration as the misoriention angle arrives -17 degree. The effect of this phase shift characteristics on the information extracted from the hologram has also been considered.
基金supported financially by the National Natural Science Foundation of China (Nos. 51590891 and 11772288)the opening project of State Key Laboratory of Explosion Science and Technology (Beijing Institute of Technology, the opening project No. KFJJ15-05M)"Hundred Talents Program" of Hunan Province, China
文摘The microstructural features of high-temperature sintered and CaO-MgO-Al_2O_3-SiO_2(CMAS) corroded air plasma sprayed Y_2O_3 stabilized ZrO_2(YSZ) thermal barrier coatings(TBCs) under the thermal gradient condition were comparatively studied. As-sprayed YSZ has a lamellar structure and the lamellae are composed of closely aligned columnar crystals. The sintered and the CMAS corroded YSZ coatings maintain the t'-ZrO_2 phase as the as-sprayed YSZ coating. The sintered YSZ remains the lamellar structure with reduced interlamellar gaps and grains coarsening. After the CMAS corrosion, the top layer of the YSZ coating keeps its lamellar structure consisting of some columnar grains with the CMAS infiltration into the intergrain gaps and the formation of striped Zr_2Y_2 O_7. The typical lamellar structure transforms into more equiaxed grains in the middle and bottom layers of the ceramic coating along with significant infiltration of amorphous CMAS and anorthite formation in the bottom layer owing to the high contents of Ca and Al.
基金Acknowledgements This work was supported by the National Basic Research Program of China (Nos. 2012CB932302, 2010CB934202 and 2013CB932904), the National Natural Science Foundation of China (No. 10974235).