检索结果-南通市图书馆

ESR　DETECTION　OF　ACTIVE　INTERMEDIATES　PRODUCED　BY　VIOLOGENMEDIATED　REDUCTION　OF　SUBSTITUTED　NITROARENES

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1996年第3期7卷 283-284页

作者： liu, FT Bai, LJ li, h he, BL NANKAI UNIV INST POLYMER CHEMTIANJIN 300071PEOPLES R CHINA NANKAI UNIV DEPT CHEMTIANJIN 300071PEOPLES R CHINA LANZhOU INST ChEM PhYS OSSO STATE KEY LABLANZHOU 730000PEOPLES R CHINA

The active intermediates 'substituted aniline radicals' were detected by ESR method duringthe reduction of substituted nitroarenes in the presence of methylviologen (MV2+) as electron-transfer catalyst (ETC).

关键词： ESR DETECTION BY ACTIVE

Recent development in the application of bulk metallic glasses

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第36期131卷 115-121页

作者： K.Gao X.G.Zhu L.Chen W.h.li X.Xu B.T.Pan W.R.li W.h.Zhou L.li W.huang Y.li Dongguan Yihao Metal Technology Co.Ltd Dongguan 523686China Dongguan Eontec Co.Ltd Dongguan 523686China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

Over the past decades,considerable efforts have been made in the commercial application of bulk metallic glasses(BMGs).Despite great challenges faced by the industrial players,significant progress has been achieved,and millions of commercial products for various kinds of applications have been shipped around the *** in this paper,we shall present the alloys suitable for the actual products in the application and discuss the merits of the processing technique of BMGs over the existing processing techniques and *** importantly we demonstrate the typical examples of products over the past few ***,future directions of the industrialization of BMGs are also discussed.

关键词： Bulk metallic glasses Commercial application Alloy design Products

A novel Mg-Gd-Y-Zn-Cu-Ni alloy with excellent combination of strength and dissolution via peak-aging treatment

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2023年第2期11卷 720-734页

作者： Y.h.liu Z.R.Zhang J.Wang Y.li h.X.li L.Y.Jia J.h.Wang J.S.Zhang State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Dekai Intelligent Casting Co. Ltd.Hebei 072750China

Inferior absolute strength and dissolution properties are the main bottlenecks for the widespread application of dissolvable magnesium alloys in complex working environments for unconventional oil and gas ***,a novel functional peak-aged Mg-9.5Gd-2.7Y-0.9Zn-0.8Cu-0.4Ni(wt.%) alloy for fracturing tools is reported,and it possesses an ultimate tensile strength of 457.6 MPa,ultimate compressive strength of 620.7 MPa and dissolution rate of ~43.7 mg·cm^(-2)·h^(-1) in 3 wt.% KCl solutions at 93℃.The excellent strength of the agedalloy is primarily attributed to the combination of grain refinement,long-period stacking ordered(LPSO) strengthening,and precipitation strengthening induced by stacking fault and β’ phase,among which the precipitation strengthening is *** investigations confirm that the corrosion is triggered from the micro-galvanic coupling between the Mg matrix and the cathodic lamellar and block LPSO ***-shaped corrosion pits along with LPSO phases are subsequently formed,significantly accelerating *** β’ precipitates can effectively improve the strength without compromising the dissolution rate because of their nanoscale *** study provides an excellent material selection for dissolvable fracturing tools and presents a strategy by which a synergistic combination of strength and dissolution rate is achieved via peak-aging treatment.

关键词： Dissolvable magnesium alloy Peak-aging treatment Mechanical properties Micro-galvanic corrosion

ON FATIGUE CRACK PATh DEVIATION AT ELEVATED TEMPERATURE IN ELECTRON BEAM REPAIRED WELDMENTS OF TURBINE DISK

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 584-590页

作者： h.Q.Zhang h.Y.Zhao Y.h.Zhang L.h.li X.A.Zhang Department of Mechanical Engineering Tsinghua University Beijing 100084 ChinaDepartment of Mechanical Engineering Tsinghua University Beijing 100084 ChinaSchool of Mechanical Engineering and Automation Beijing University of Aeronautics and AstronauticsBeijing 100083 ChinaSchool of Mechanical Engineering and Automation Beijing University of Aeronautics and AstronauticsBeijing 100083 ChinaBeijing Institute of Aeronautical Materials Beijing 100095 China

Fatigue crack growth behaviors in electron beam weldments of a nickel-base superalloy are studied. The objective of this paper is to discuss effects of the inhomogeneity of mechanical performance on fatigue crack growth (FCG) rate and crack path deviation (CPD). The base metal served in a turbine disk of aerospace engine was selected to fabricate bead-on-plate weldments by using electron beam welding. Some wedge-type opening loading specimens, notched in three different zone of weld metal, hAZ and base metal, were employed and performed fatigue crack growth tests at 650℃. The results show that the fatigue crack growth of electron beam welded joints is instable due to the influence of mechanical heterogeneities. Owing to the crack deviation at the weld metal and heat-affected-zone (hAZ), the effective growth driving force at the tip of fatigue crack was reduced with the reduction of the effective stress intensity factor (SIF) which finally causes fatigue crack rate decrease. Fatigue crack was strongly affected by size and the symmetrical characteristics of the plastic zone at the crack tip, which means that the integrity of the welded structure containing the fatigue crack mainly depended on the toughness of the low strength zone.

关键词： fatigue crack growth crack path deviation electron beam welding inhomogeneity of mechanical performance

Modeling biomembranes and red blood cells by coarse-grained particle methods

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2018年第1期39卷 3-20页

作者： h.li h.Y.ChANG J.YANG L.LU Y.h.TANG G.LYKOTRAFITIS Division of Applied Mathematics Brown University Department of Materials Science and Engineering Massachusetts Institute of Technology Department of Mechanical Engineering University of Connecticut

In this work, the previously developed coarse-grained （CG） particle models for biomembranes and red blood cells （RBCs） are reviewed, and the advantages of the CG particle methods over the continuum and atomistic simulations for modeling biological phenomena are discussed. CG particle models can largely increase the length scale and time scale of atomistic simulations by eliminating the fast degrees of freedom while preserving the mesoscopic structures and properties of the simulated system. Moreover, CG particle models can be used to capture the microstructural alternations in diseased RBCs and simulate the topological changes of biomembranes and RBCs, which are the major challenges to the typical continuum representations of membranes and RBCs. The power and versatility of CG particle methods are demonstrated：through simulating the dynamical processes mvolving significant topological .changes e.g. lipid self-assembly vesicle fusion and membrane budding.

关键词： coarse-grained molecular dynamics,lipid bilayer red blood cell membrane membrane fusion

Crack initiation of granite under uniaxial compression tests:A comparison study

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2020年第3期12卷 656-666页

作者： G.K.Zhang h.B.li M.Y.Wang X.F.li State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094China University of Chinese Academy of Sciences Beijing100049China

In this study,a combination of acoustic emission(AE)method(AEM)and wave transmission method(WTM)is used to investigate the behaviors of AE and ultrasonic properties corresponding to initial fracturing in granitic *** relationships of AE characteristics,frequency spectra,and spatial locations with crack initiation(CI)are *** anisotropic ultrasonic characteristics,velocity distributions in different ray paths,wave amplitudes,and spectral characters of transmitted waves are *** identify CI stress,damage initiations characterized by strain-based method(SBM),AEM and WTM are *** granite samples,it shows that the ratio of CI stress to peak strength estimated by SBM ranges from 0.4 to 0.55,and 0.49-0.6 by WTM,which are higher than that of AEM(0.38-0.46).The CI stress identified by AEM indicates the onset of microcracking,and the combination of AEM and WTM provides an insight into the detection of rock damage initiation and anisotropy.

关键词： Crack initiation(CI)stress Acoustic emission(AE) Ultrasonic transmission Wave velocity Granite

Effect of nitrogen on deposition and field emission properties of boron-doped micro-and nano-crystalline diamond films

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2010年第3期2卷 154-159页

作者： L.A.li S.h.Cheng h.D.li Q.Yu J.W.liu X.Y.Lv State Key Laboratory of Superhard Materials Jilin University

In this paper,we report the effect of nitrogen on the deposition and properties of boron doped diamond films synthesized by hot filament chemical vapor *** diamond films consisting of micro-grains(nano-grains) were realized with low(high) boron source flow rate during the growth *** transition of micro-grains to nano-grains is speculated to be strongly(weekly) related with the boron(nitrogen) flow *** grain size and Raman spectral feature vary insignificantly as a function of the nitrogen introduction at a certain boron flow *** variation of electron field emission characteristics dependent on nitrogen is different between microcrystalline and nanocrystalline boron doped diamond samples,which are related to the combined phase composition,boron doping level and texture *** is an optimum nitrogen proportion to improve the field emission properties of the boron-doped films.

关键词： Chemical vapor deposited diamond film Nitrogen effect Boron doping Microcrystalline Nanocrystalline Electron field emission

IMPROVED COhESIVE ZONE MODEL AND ITS APPliCATION IN INTERFACE CONTACT ANALYSIS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2008年第4期21卷 295-302页

作者： Y. Wang J. Chen h.B. li National Die ＆ Mold CAD Engineering Research Center Shanghai Jiaotong University Shanghai 200030China

An improved interface cohesive zone model is developed for the simulation of interface contact, under mixed-mode loading. A new debonding initiation criterion and propagation of debonding law, taking into account the pressure stress influence on contact shear strength, is proposed. The model is implemented in a finite-element program using subroutine VUINTER of ABAQUS Explicit. An edge-notch four-point bending process and laminated vibration damping steel sheet punch forming test are simulated with the improved model in ABAQUS Explicit. The numerical predictions agree satisfactorily with the corresponding experimental results.

关键词： Cohesive zone model Mixed mode Damage criterion Contact stress

RECRYSTALliZATION BEhAVIOR AND PRIOR AUSTENITE GRAIN BOUNDARY CORROSION IN ThE PLANE STRAIN COMPRESSION CONDITION FOR A LOW CARBON X70 PIPEliNE STEEL

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2004年第6期17卷 830-834页

作者： Y.h.li J.Wang Y.S.li Y.KShan Dep.ofMaterialScienceandEngineering ShenyangLigongUmversityShenyang110168China InstituteofIndustry NingboPolytechnicNingbo315800China SchoolofMaterial＆ChemicalEngineering SouthernInstituteofMetallurgy＇Ganzhou341000China InstituteofMetalResearch TheChineseAcademyofSdencesShenyang110016China

Recrystallization behavior of a low carbon X70 pipeline steel was studied in the plane strain compression condition. It was found that the dynamic recovery but no dynamic recrystal- lization occurred in the current ex... 详细信息

关键词： pipeline steel, plane strain compression, recrystallization, austenite grain boundary