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Carbon fluxes and species diversity in grazed and fenced typical steppe grassland of Inner Mongolia, China

journal of Plant Ecology 2019年第1期12卷 10-22页

作者： R.Sagar G.y.Li j.S.Singh Shiqiang wan Department of Botany Institute of ScienceBanaras Hindu UniversityVaranasi-221005India International joint Research Laboratory for Global Change Ecology College of Life SciencesHenan UniversityKaifeng 475004China

Aim Grasslands are dominant vegetation of China,support outstanding biodiversity and sequester bulk amount of atmospheric CO_(2).These grasslands are highly degraded and fragmented due to remarkable anthropogenic and grazing *** Government has made great attempt to restore by grazing *** relations of carbon fluxes with species composition and diversity in the communities sensitive to grazing by large herbivores are needed to be analysed under the global climate change *** objective of present study was to comprehend the effects of grazing and fencing on the ecosystem structure and function of the typical steppe *** To meet the objectives,overgrazed and fenced(since year 2001)sys-tems were selected in typical steppe grassland at the Duolun Restoration Ecology Research Station,Inner Mogolia,*** each system,three dominant communities with three replicates were *** each replicate community,three 1×1 m plots,were randomly *** plot was divided into four 50×50 cm quadrats.A total of 216,50×50 cm quadrats were *** each quadrat,number of individuals and above-ground herbaceous biomass for each species,soil respiration(SR),ecosystem respira-tion(ER),net(NEE)as well as gross(GEE)ecosystem CO_(2) exchanges were recorded in june *** were well analysed using statistical *** correspondence analysis showed dif-ferential responses of communities to the structure and function of the typical steppe *** Findings Across the communities,fencing reduced the soil tempera-ture by 12%and at the same time increased the soil moisture by 44.30%,thus,increased the species richness by 28%,evenness by 21%,above-ground biomass by 19%and plant carbon by 20%.Interestingly,fencing increased NEE by 128%,GEE by 77%,SR by 65%and ER by 39%.Under fencing,species composition partially governed the CO_(2) exchange *** Fencing reduces soil temperature and thereby improves specie

关键词： canonical correspondence analysis ecosystem carbon uptake grazing species composition species evenness species richness

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The microstructure characteristics and fracture behavior of the polyhedral primary iron-rich phase and plate-shaped eutectic iron-rich phase in a high-pressure die-cast AlSi10MnMg alloy

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journal of Materials Science & Technology 2023年第9期140卷 201-209页

作者： X.y.jiao y.X.Liu j.wang W.N.Liu A.X.wan Stuart Wiesner S.M.Xiong School of Materials Science and Engineering Northeastern UniversityShenyang 110819China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Lightweight Structural Materials Liaoning ProvinceNortheastern UniversityShenyang 110819China Key Laboratory for Advanced Materials Processing Technology Tsinghua UniversityBeijing 100084China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China Ein Unternehmen der ALUMINIUM RHEINFELDEN Group RHEINFELDEN 79618Germany

The characterization of multiple iron-rich phases in high-pressure die-cast AlSi10MnMg alloy was *** was focused on the formation and fracture behavior of the primary iron-rich phase((P-IMC)_(I))formed in the shot sleeve and plate-shaped eutectic iron-rich phase in high-pressure die cast(HPDC)AlSi10MnMg *** show that multiple types of iron-rich phases with various morphologies,in-cluding primary iron-rich phases(polyhedral(P-IMC)_(I) and(P-IMC)_(II))and eutectic iron-rich phases(plate-shaped,net shape,and fish-bone shape),were found in HPDC ***(P-IMC)_(I) formed in the shot sleeve were distributed in the interface between primaryα-Al and binary Al-Si *** size(P-IMC)_(II) and various eutectic iron-rich phases formed in the die cavity and they were distributed in Al-Si binary *** primary iron-rich phases belonged to a simple cubic crystal structure with a lattice constant a=1.265 nm and they exhibited a lateral growth characteristic with a termination of{110}surface.βphase was surrounded byδphase and they coexisted in a plate-shaped iron-rich ***-density stacking fault inβphase andδ/βinterface provided an excellent nucleation site forδ*** mechanical behavior,the stress concentration caused by eutectic iron-rich phases was far less than(P-IMC)_(I) and it would not cause crack initiation along the eutectic cluster *** addition,(P-IMC)_(I) showed the worst deformation coordination with primaryα-Al while the plate-shaped eutectic iron-rich phase exhibited similar deformation characteristics with silicon particles.

关键词： AlSi10MnMg High-pressure die casting Multiple iron-rich phases

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一种改进诱导因子计算方法的叶素动量理论体积力模型

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船舶力学 2024年第1期28卷 1-9页

作者：王明哲王建华万德成上海交通大学船海计算水动力学研究中心(CMHL) 上海200240 上海交通大学船舶海洋与建筑工程学院上海200240

叶素动量理论体积力模型作为能够替代真实螺旋桨的一种体积力形式,在模拟螺旋桨以及船桨相互作用问题中具有较大的应用潜力。为了处理基于理想流体假设的传统叶素动量理论在与粘性求解器耦合过程中不能在较大工况范围内准确代表真实螺... 详细信息

叶素动量理论体积力模型作为能够替代真实螺旋桨的一种体积力形式,在模拟螺旋桨以及船桨相互作用问题中具有较大的应用潜力。为了处理基于理想流体假设的传统叶素动量理论在与粘性求解器耦合过程中不能在较大工况范围内准确代表真实螺旋桨模型的问题,本文提出一种基于真实螺旋桨诱导因子分布的改进方法,并进行KP505螺旋桨体积力模型在j=0.4~0.8五种进速条件下的敞水试验模拟。本文将敞水性能、桨载荷分布与诱导速度场的体积力模拟结果与真实螺旋桨模型进行了对比,结果表明改进后的体积力模型预报敞水性能误差在各进速下最大值为1.05%,且体积力模型诱导速度场可以反映真实螺旋桨尾流的动量输运。

关键词：诱导因子叶素动量理论体积力模型敞水试验数值模拟

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钌基氧化物酸性析氧电催化剂

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科学通报 2024年第25期69卷 3705-3714页

作者：万仁典黄广幸刘庆勋赵伯特华南理工大学环境与能源学院

质子交换膜(proton exchange membrane, PEM)电解水技术是一种很有前景的绿色制氢技术,但其酸性操作环境对催化剂的性质提出更苛刻的要求.目前,可商业化应用于PEM电解水技术酸性析氧反应(oxygen evolution reaction, OER)的催化剂主要... 详细信息

质子交换膜(proton exchange membrane, PEM)电解水技术是一种很有前景的绿色制氢技术,但其酸性操作环境对催化剂的性质提出更苛刻的要求.目前,可商业化应用于PEM电解水技术酸性析氧反应(oxygen evolution reaction, OER)的催化剂主要为贵金属铱(Ir)基材料.与Ir基材料相比,钌(Ru)基氧化物催化剂具有成本相对较低的优势.然而, Ru基氧化物催化剂在酸性介质中的稳定性较差.因此,迫切需要研制出在酸性电解质中高效稳定的Ru基氧化物OER催化剂.本文综述了Ru基氧化物催化剂的理论稳定性、析氧反应机理和理论活性,随后探讨了该催化剂在析氧反应过程中的性能衰减机理,并进一步讨论了提高其反应活性和稳定性的设计策略.本文最后总结了Ru基氧化物催化剂目前面临的挑战,并提出了相应的展望.

关键词：电解水钌基氧化物衰减机理催化剂设计策略

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Extracellular vesicle activities regulating macrophage- and tissue-mediated injury and repair responses

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Acta Pharmaceutica Sinica B 2021年第6期11卷 1493-1512页

作者： Qian Hu Christopher j.Lyon jesse K.Fletcher Wenfu Tang Meihua wan Tony y.Hu Department of Integrated Traditional Chinese and Western Medicine West China HospitalSichuan UniversityChengdu 610041China Center of Cellular and Molecular Diagnosis Tulane University School of MedicineNew OrleansLA 70112USA Department of Biochemistry&Molecular Biology Tulane University School of MedicineNew OrleansLA 70112USA

Macrophages are typically identified as classically activated(M1) macrophages and alternatively activated(M2) macrophages,which respectively exhibit pro-and anti-inflammatory phenotypes,and the balance between these two subtypes plays a critical role in the regulation of tissue inflammation,injury,and repair *** studies indicate that tissue cells and macrophages interact via the release of small extracellular vesicles(EVs) in processes where EVs released by stressed tissue cells can promote the activation and polarization of adjacent macrophages which can in turn release EVs and factors that can promote cell stress and tissue inflammation and injury and vice *** review discusses the roles of such EVs in resulating such interactions to influence tissue inflammation and injury in a number of acute and chronic inflammatory disease conditions,and the potential applications,advantage and concerns for using EV-based therapeutic approaches to treat such conditions,including their potential role of drug carriers for the treatment of infectious diseases.

关键词： Extracellular vesicles Macrophage Tissue injury Inflammatory disease Interaction loop Stem cell Sepsis Targeted therapy

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IN SITU OBSERVATION OF GROWTH BEHAVIOR AND MORPHOLOGy OF DELTA-FERRITE AS FUNCTION OF SOLIDIFICATION RATE IN AN AISI304 STAINLESS STEEL

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Acta Metallurgica Sinica(English Letters) 2006年第6期19卷 441-448页

作者： G.F.Liang C.Q.wan j.C.Wu G.M.Zhu y.yu y.Fang Advanced Technology Institute Technology Center of BaosteelShanghai 201900China Department of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200030China

It was presented the in situ observation of growth behavior and morphology of delta-ferrite as a function of solidification rate in an AISI304 stainless steel. The specimens have been solidified and observed using confocal scanning laser microscopy (CSLM). The δ-phase always appears like cells on the sample surface when critical supercooling occurs, during which the L→δ transformation starts. The solid-liquid (S-L) interface is found to be finger shaped and has no faceted shape. γ phase appears among δ grains due to partitioning of Ni into the melt during solidification, when solidification rate is higher. The mergence of observed δ cells is possible for the steel sample cooled at 7.5℃/min. The formation of dendrites can be observed on the free surface of the steel sample cooled at 150℃/min. The size of solidified delta grains decreases from 120 to 20-80μm, and the volume fraction of solidified austenite increases with increase in solidification rate from 7.5 to 150℃/min. The relation between the tip radius of δ cell and its growth rate is deduced, and the results agree with the experimental values.

关键词： stainless steel confocal scanning laser microscopy δ-ferrite in situ observation solidification

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Effect of scanning strategy on grain structure and crystallographic texture of Inconel 718 processed by selective laser melting

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journal of Materials Science & Technology 2018年第10期34卷 1799-1804页

作者： H.y. wan Z.j. Zhou C.P. Li G.F. Chen G.P. Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China School of Materials Science and Engineering University of Science and Technology of China Shenyang 110016 China Materials & Manufacturing Qualification Group Corporate Technology Siemens Ltd. Beijing 100102 China

Two types of scanning strategies were adopted to study the effect of scanning strategy on grain structure and crystallographic texture of selective laser melted （SLM） Inconel 718. The results show that bidirec-tional scanning without and with a 90°-rotation for every layer produced the bimodal grain structure and the directional columnar grain structure, respectively. Controlling the heat flux direction between the successive layers via scanning strategy enabled the formation of such different grain structures. Fur-thermore, when the 90°-rotation was applied, the competitive grain growth mechanism became more pronounced and the strong cube texture developed.

关键词： Selective laser melting Additive manufacturing Scanning strategy Texture Grain structure

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EFFECT OF Fe ON SURFACE REACTION OF Co_(3)Ti WITH WATER VAPOR

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中国有色金属学会会刊:英文版 1999年第S1期9卷 142-145页

作者： y.X.Chen X.j.wan W.X.Xu Shanghai University Shanghai 200072China Shanghai Iron and Steel Research Institute Shanghai 200940China

The surface reaction of Co 3Ti alloys (with and without Fe) with water vapor was investigated by using Auger electron spectroscopy (AES). The results showed that the rate of the surface reaction is much lower in Co 21 5Ti 3Fe alloy as compared with Co 3Ti (Co 23Ti) alloy. The surface reaction of Co 21 5Ti 3Fe alloy with water vapor saturates at exposure of 2×10 -3 Pa·s, but it does not saturate even at 0 1 Pa·s exposure for Co 3Ti alloy without Fe. The results also indicated that the kinetic of the surface reaction of Co 21 5Ti 3Fe with water vapor is much smaller than that of Co 3Ti at the same exposure. All the above results illustrate that the suppression of environmental embrittlement by addition of Fe to Co 3Ti alloy is attributed to its reduction of the surface reaction kinetics with water vapor.

关键词： Co_(3)Ti surface reaction water vapor Fe doping

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Solid-state alloying of Al-Mg alloys by accumulative roll-bonding:Microstructure and properties

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journal of Materials Science & Technology 2022年第30期125卷 238-251页

作者： X.M.Mei Q.S.Mei j.y.Li C.L.Li L.wan F.Chen Z.H.Chen T.Xu y.C.wang y.y.Tan School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China Key Laboratory of Hydraulic Machinery Transients(Wuhan University) Ministry of EducationWuhan 430072China School of Mechanical Engineering Wuhan Polytechnic UniversityWuhan 430023China

In this study,a novel solid-state alloying approach was adopted to fabricate Al-Mg alloys with high Mg contents(C_(Mg)) by accumulative roll-bonding(ARB)of Al and Mg elemental materials to ultrahigh *** results showed that the degree of alloying increased with the increase of ARB cycles and a supersaturatedα-Al solid solution accompanied with nanoprecipitates was formed in the Al-Mg alloys by ARB to 70 *** as-prepared Al-Mg alloys exhibited enhanced mechanical properties,with a maximum tensile strength of∼615 MPa and a tensile elongation of∼10%at C_(Mg)=13 wt.%.The high strength can be attributed to different mechanisms,namely solid solution strengthening,grain boundary strengthening,dislocation strengthening,and precipitation *** Al-Mg alloys showed increased work hardening with increasing C_(Mg),due to the enhanced formation of ***,no obvious drop in the intergranular corrosion(IGC)resistance was found in the Al-Mg alloys with C_(Mg) up to 13 wt.%.Moreover,sensitization treatment was found to induce little decrease in the IGC resistance of the Al-Mg alloys with C_(Mg)≤13 wt.%.We found that the excellent IGC resistance was due to the suppression of grain boundary precipitation by the preferred formation of precipitates within the grains that were induced by *** study indicated the novelty of the present solid-state alloying approach to achieving a superior combination of high mechanical properties and IGC resistance in Al-Mg alloys.

关键词： Solid-state alloying Al-Mg alloys Mechanical properties IGC resistance ARB

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Mn^(2+)掺杂Cs_(3)Cu_(2)I_(5)微晶的温和、快速溶液法合成

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发光学报 2024年第3期45卷 375-382页

作者：严鑫鑫胡扬香万凝庞起陈旖勃广西大学化学化工学院省部共建特色金属材料与组合结构全寿命安全国家重点实验室广西南宁530004 广州大学化学化工学院清洁能源与材料研究所广东广州510006

在铜基金属卤化物Cs_(3)Cu_(2)I_(5)中掺杂Mn^(2+)是拓宽发光范围的重要途径,但是已报道的掺杂方法大多需要高温、惰性气氛、较长时间和专用设备等。本工作将CsI固体粉末直接投加至CuI和MnCl_(2)的氢碘酸溶液中,在较低温度(60℃)、空气... 详细信息

在铜基金属卤化物Cs_(3)Cu_(2)I_(5)中掺杂Mn^(2+)是拓宽发光范围的重要途径,但是已报道的掺杂方法大多需要高温、惰性气氛、较长时间和专用设备等。本工作将CsI固体粉末直接投加至CuI和MnCl_(2)的氢碘酸溶液中,在较低温度(60℃)、空气条件下快速(3 min)合成Mn^(2+)掺杂Cs_(3)Cu_(2)I_(5)微晶,并测试了其结构和发光性能。通过系列对比实验,提出一种由反应物溶解度控制的“缓释生长-掺杂”机制,证实CsI固体粉末在高浓度氢碘酸中的缓慢溶解能够降低Cs_(3)Cu_(2)I_(5)晶体的生长速率,为Mn^(2+)的低温、可控掺杂提供有利的动力学条件。该方法为全无机金属卤化物体系的掺杂发光和掺杂动力学研究提供了新的思路。

关键词： Mn^(2+)掺杂缓释生长-掺杂 Cs_(3)Cu_(2)I_(5)

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