检索结果-南通市图书馆

Altitudinal variations of hydraulic traits in Faxon fir(Abies fargesii ***):Mechanistic controls and environmental adaptability

引用

Forest Ecosystems 2022年第3期9卷 427-438页

作者： Shao-an Pan Guangyou Hao Xuhua Li Qiuhong Feng Xingliang Liu Osbert j.sun School of Ecology and Nature Conservation Beijing Forestry UniversityBeijing100083China Institute of Forestry and Climate Change Research Beijing Forestry UniversityBeijing100083China Institute of Applied Ecology Chinese Academy of SciencesShenyang110016China Sichuan Provincial Key Laboratory of Ecological Restoration and Conservation for Forest and Wetland Sichuan Academy of Forestry SciencesChengdu610081China Sichuan Wolong Forest Ecosystem Research Station Wenchuan623006China

Global climate change has been seen to result in marked impacts on forest ecosystems such as accelerated tree mortality worldwide due to incidental hydraulic failure caused by intensified and more frequent occurrence of extreme drought and ***,it is well understood how the tree hydrological strategies would adjust to environmental variability brough about by climate *** we investigated the hydraulic adjustment as a mechanism of acclimation to different climate conditions along an altitudinal gradient in Faxon fir(Abies fargesii ***)–a tree species that plays a key role in conservation of wildlife and maintenance of ecosystem services in subalpine *** hydraulic traits and selective morphological and physiological variables were measured seasonally along an altitudinal gradient from 2,800 to 3,600 m *** found that the native percentage loss of conductivity(PLC)increased with altitude across the seasonal *** the native sapwood-specific hydraulic conductivity(Ks)and native leaf-specific hydraulic conductivity(Kl)significantly decreased with altitude for measurements in july and October,coinciding with the timing for peak growth and pre-dormancy,*** morphological traits varied toward more conservative tree hydrological strategies with increases in altitude,exhibiting trade-offs with hydraulic *** total non-structural carbohydrates in both needle(NSCNeedle)and branch(NSCBranch)as well as photosynthetic capacity of current-year leaves played variable roles in maintaining the integrity of the hydraulic functioning and shaping the hydraulic adjustment under prevailing environmental *** findings indicate that Faxon fir possesses some degree of hydraulic adaptability to water limitation imposed by climate fluctuations in subalpine region through morphological and physiological modifications.

关键词： Climate change Eco-safety Environmental vulnerability Faxon fir Hydraulic risk Habitat constraints Water stress Subalpine

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A strong and ductile NiCoCr-based medium-entropy alloy strengthened by coherent nanoparticles with superb thermal-stability

引用

journal of Materials Science & Technology 2023年第1期132卷 201-212页

作者： D.D.Zhang j.Kuang H.Xue j.Y.Zhang G.Liu j.sun State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China

In this work,we designed a novel NiCoCr-based medium-entropy alloy(MEA)strengthened by coher-ent L12-nanoparticles,i.e.,(NiCoCr)92 Al 6 Ta 2(at.%).The strengthening and deformation mechanisms of the material and the coarsening kinetics of the coherent precipitates were systematically *** results indicated that giant precipitation hardening and its synergy with other strengthening contributors confer on the aged material a yield strength as high as 1.0 ***,a unique particle-features-dependent plasticity mechanism was revealed in this *** is,the alloy with a lower volume frac-tion,denser distribution,and finer particles mainly deformed by dislocation planar slip,otherwise,stack-faults-mediated plasticity was favored,rationalized by the cooperative/competitive effect of stack-fault energy,spatial confinement,and applied ***,the coarsening behavior of precipitate fol-lowed a modified Lifshitz-Slyozov-Wagner(LSW)model,and the nanoparticles displayed remarkably su-perior thermal stability compared to most traditional superalloys and reported multicomponent *** superb coarsening resistance of precipitate originated from the coupled effect of intrinsic sluggish diffusion in multi-principal alloys and the dual-roles of Ta species as a precipitate *** work provides a new pathway to develop strong-yet-ductile multicomponent alloys as promising candidates for high-temperature applications.

关键词： Medium-entropy alloy Mechanical properties Precipitation hardening Deformation mechanisms Coarsening kinetics

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Eutectic-reaction brazing of Al_(0.3)CoCrFeNi high-entropy alloys using Ni/Nb/Ni interlayers

引用

journal of Materials Science & Technology 2022年第26期121卷 245-255页

作者： Y.Lei j.sun X.G.Song M.X.Yang T.L.Yang j.Yin State Key Laboratory of Advanced Welding and joining Harbin Institute of TechnologyHarbin 150001China Beijing Power Machinery Institute Beijing 100074China Sichuan Aerospace Changzheng Equipment Manufacturing Co. Ltd.Chengdu 610100China

In this study,a novel eutectic-reaction brazing of Al_(0.3)CoCrFeNi high-entropy alloys(HEAs)^(1)was investigated with a design of laminated Ni/Nb/Ni *** typical Al_(0.3)CoCrFeNi brazing seam consisted of proeutecticγ,the lamellar eutectic structure composed of face-centered cubic(FCC)phase(eutecticγ)and C14 Laves,as well as a few amounts of Nb based solid solution.A high density of nanoscale ordered L1_(2)(γ)phase was precipitated withinγphase *** the brazing temperature raised from 1200 to 1320℃,the dissolution volume of Al_(0.3)CoCrFeNi alloy into Ni-Nb liquid was *** microstructure of the brazing seam changed from hypereutectic(blocky Laves+γphase)to eutectic(Laves+eutecticγ)to hypoeutectic structures(proeutecticγ+Laves/γeutectic structure).The shear strength of joints was increased gradually due to the formation of eutectic lamellae and the cellular growth of proeutecticγ*** maximum shear strength of the joint brazed at 1320℃for 10 min was up to 592 MPa,reaching 95%of the base *** joint mainly ruptured in the soft proeutecticγphase in a ductile fracture mode.

关键词： High-entropy alloys Brazing Eutectic structure Shear strength

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Hot Corrosion Behavior of Hf-Doped NiAl Coating in the Mixed Salt of Na_(2)SO_(4)+K_(2)SO_(4)at 900℃

引用

金属学报:英文版 2023年第9期36卷 1409-1420页

作者： W.L.Zhang W.Li L.B.Fu X.Peng j.sun S.M.jiang j.Gong C.sun Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China Advanced Research Institute for Multidisciplinary Science Qilu University of Technology(Shandong Academy of Sciences)Jinan250353China

The hot corrosion behavior of the NiAl coating and the 5Hf-NiAl coating induced by mixed salt at 900℃was *** with the NiAl coating,the 5Hf-NiAl coating exhibited superior hot corrosion resistance because the addition of Hf promoted the formation of protective oxide scale and reduced the growth rate of oxide ***,internal sulfides were not present in the 5Hf-NiAl coating after hot corrosion for 140 *** exhibited different distribution in the two coatings since the addition of Hf changed the hot corrosion process of the *** and Ti in the 5Hf-NiAl coating trapped and captured sulfur,preventing the penetration of sulfur into the *** hot corrosion mechanism of the two coating and the effects of Hf on this process were discussed in this work.

关键词： Hot corrosion Hafnium Oxide scale Titanium Sulfide

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Enhancing the high-temperature creep properties of Mo alloys via nanosized La_(2)O_(3) particle addition

引用

journal of Materials Science & Technology 2022年第35期130卷 53-63页

作者： P.M.Cheng C.Yang P.Zhang j.Y.Zhang H.Wang j.Kuang G.Liu j.sun State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China School of Mechanical Engineering Chengdu UniversityChengdu 610106China

Molybdenum(Mo) alloys with different La_(2)O_(3)particle additions(0.6,0.9,1.5 wt.%) were prepared by powder metallurgy to investigate the effect of La_(2)O_(3)particles on microstructural evolution and creep behavior of the *** Mo,annealed at 1500℃ for 1 h,presented a fully recrystallized microstructure characterized by equiaxed *** alloys doped with La_(2)O_(3)particles(Mo-La_(2)O_(3)alloys),on the other hand,exhibited fibrous grains elongated in the rolling direction of the *** contrast to the shape of the grains,the average grain size of the alloys was found to be insensitive to the addition of La_(2)O_(3)*** La_(2)O_(3)particles with diameters ranging from 65 to 75 nm were distributed within the grain *** creep tests showed that dislocation creep was the predominant deformation mode at intermediate creep rate(10^(-7)s^(-1)-10^(-4)s^(-1)) in the present *** creep stress exponent and activation energy were found to decrease with increasing temperature,particularly within the low creep rate regime(jor creep strengthening mechanism in the Mo-La_(2)O_(3)*** addition,the area reduction and creep fracture mode of the Mo-La_(2)O_(3)alloys were found to be a function of the creep rate and temperature,which can be explained by the effect of the two parameters on the creep and fracture mechanisms.

关键词： Mo alloys Nanosized particles Creep strength Deformation and fracture

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Deformation kinking and highly localized nanocrystallization in metastableβ-Ti alloys using cold forging

引用

journal of Materials Science & Technology 2022年第25期120卷 53-64页

作者： Keer Li W.Chen G.X.Yu j.Y.Zhang S.W.Xin j.X.Liu X.X.Wang j.sun State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China Northwest Institute for Nonferrous Metal Research Xi’an 710016China Baoji Titanium Industry Co. Ltd.Baoji 721014China

Deformation kinking as an uncommon plastic deformation mechanism has been reported in several materials while the relevant microstructure evolution and grain refinement behavior at a large strain remain unclear so *** this study,the issue was systematically investigated by utilizing cold forging to impose severe plastic deformation(SPD)on Ti-11 V metastableβ-Ti *** is found that the formation of kink bands experiences dislocation gliding,pre-kinking and the ripening of pre-kinks in *** kink bands are subsequently thickened through the coalescence of multiple kink bands in a manner of high *** dislocation slip is developed as a dominant deformation mechanism when deformation kinking is *** resulting grain refinement involves transverse breakdown and longitudinal splitting of dislocation walls and cells,which fragment kink bands into smallβ-*** refinement of theβ-blocks is still governed by dislocation activities,and finally nanograins with a diameter of~15 nm are produced at a large strain of ***,it is revealed that nanocrystallization is highly localized inside kink bands while the outer microstructure maintains original coarse *** localized refinement characterization is ascribed to the intrinsic soft nature of kink bands,shown as low hardness in nanoindentation *** intrinsic softening of kink bands is uncovered to originate from the inner degraded dislocation density evidenced by both experimental measurement and theoretical *** findings enrich fundamental understanding of deformation kinking,and shed some light on exploring the deformation accommodation mechanisms for metal materials at large strains.

关键词： Metastableβ-Ti alloys Deformation kinking Microstructural evolution Grain refinement Dislocations

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Formation process and oxidation behavior of MCrAlY+AlSiY composite coatings on a Ni-based superalloy

引用

journal of Materials Science & Technology 2022年第25期120卷 65-77页

作者： S.M.Li L.B.Fu W.L.Zhang W.Li j.sun T.G.Wang S.M.jiang j.Gong C.sun School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Advanced Research Institute for Multidisciplinary Science Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China Tianjin Key Laboratory of High Speed Cutting and Precision Machining Tianjin University of Technology and EducationTianjin 300222China

An AlSiY coating and two MCrAlY+AlSiY composite coatings with different thickness of MCrAlY interlayer were prepared by arc ion plating(AIP)and vacuum *** isothermal oxidation behavior of coatings at 1100℃ for 300 h was also investigated to characterize the microstructure evolution of coatings during *** composite coatings exhibited a better high-temperature oxidation resistance at 1100℃ .The reason is that the addition of MCrAlY layer can greatly contribute to prevent the diffusion of refractory elements to the outer *** inhibition of Al inward diffusion can be much stronger,as the Si content increases in the outer layer during annealing.

关键词： Composite coating Annealing Arc ion plating SEM Oxidation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Unusual He-ion irradiation strengthening and inverse layer thickness-dependent strain rate sensitivity in transformable high-entropy alloy/metal nanolaminates:A comparison of Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu vs Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu

引用

journal of Materials Science & Technology 2022年第21期116卷 199-213页

作者： Y.F.Zhao H.H.Chen D.D.Zhang j.Y.Zhang Y.Q.Wang K.Wu G.Liu j.sun State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China

In this work,we prepare transformable HEA/Cu nanolaminates(NLs)with equal individual layer thick-ness(h)by the magnetron sputtering technique,i.e.,Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu and Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu,and comparatively study He-ion irradiation effects on their microstructure and mechanical *** ap-pears that the as-deposited HEA/Cu NLs manifest two size h-dependent hardness regimes(i.e.,increased hardness at small h and hardness plateau at large h),while the He-implanted ones exhibit monotonically increased *** to the fashion that smaller h renders less irradiation hardening in bimetal NLs,the Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu NLs manifest the trend that smaller h leads to greater irradiation *** contrast,the Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu NLs exhibit the maximum irradiation hardening at a critical h=50 *** this critical size,smaller h results in lower radiation hardening(similar to bimetal NLs),while above this size,smaller h results in greater radiation hardening(similar to Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu NLs).Moreover,these transformable HEA/Cu NLs display inverse h-dependent strain rate sensitivity(SRS m)before and after He-ion ***,compared with as-deposited samples,the irradi-ated Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu NLs display reduced SRS,while the irradiated Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu NLs dis-play enhanced *** unusual size-dependent irradiation strengthening and inverse h effect on SRS in irradiated samples were rationalized by considering the blocking effects of He bubbles on dislocation nucleation and motion,i.e.,dislocations shearing or bypassing He bubbles.

关键词： High entropy alloy/metal nanolaminates Interfaces Irradiation hardening Strain rate sensitivity Size effects

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Designing hetero-structured ultra-strong and ductile Zr-2.5Nb alloys:Utilizing the grain size-dependent martensite transformation during quenching

引用

journal of Materials Science & Technology 2022年第30期125卷 198-211页

作者： S.Y.Liu j.Y.Zhang j.Kuang X.Y.Bao D.D.Zhang C.L.Zhang j.K.Yang G.Liu j.sun State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China

To further improve the service performance of Zr-2.5Nb alloy worked as pressure tubes in pressurized heavy water reactors,more investigation about the microstructure and thermomechanical processing route of Zr-2.5Nb alloy need to be *** this work,a hetero-structured Zr-2.5Nb alloy was prepared by applying a novel *** analysis reveals that the alloy exhibits a grain sizedependent martensite substructure transition during post-rolling *** hetero-structure consists of equiaxed primaryαgrains and the lamellae groups containing both parallelα’dislocation martensite andα’twin *** with the previously reported Zr-Nb alloys,the present Zr-2.5Nb alloys manifest the highest yield strength(∼710 MPa),together with a high ultimate tensile strength(∼844 MPa)and good ductility(∼17.1%).The enhanced mechanical properties are found to arise from the properly controlled fraction/size of the two types of martensite,which not only significantly strengthens the alloy but also contributes to a stronger strain hardening.A model based on the grain-size-dependent critical resolved shear stress for dislocation slip and twinning has been proposed to explain theα’martensite substructures transition at a critical grain size dc=3.3μ*** this size,the critical resolved shear stress(CRSS)for twinning is higher than that for the***,theα’dislocation martensite is more favorable to ***,theα’twin martensite would exhibit a high *** present work indicates that making use of the grain size-dependent martensite transformation to tailor the heterostructure in Zr alloys is an effective strategy to overcome the strength–ductility trade-off in the material.

关键词： Zr-Nb alloys Heterogeneous structure Martensitic transformation Grain size Strength

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于血凝块的时间密度曲线作为急性缺血性卒中机械取栓功能性结局的新型影像学预测因子

引用

国际医学放射学杂志 2024年第3期 376-376页

作者： j.Wei j.jiang Y.Zhu X.Wei Z.sun j.sun 吴小佳

摘要目的从CT灌注成像（CTP）中获得的血栓通透性的新评价指标可否更准确地预测急性缺血性脑卒中（AIS）中机械血栓切除术（MT）的临床反应。方法研究纳入2018年4

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：