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Effects of ausforming strain on bainite transformation in nanostructured bainite steel

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International Journal of Minerals,Metallurgy and Materials 2017年第3期24卷 264-270页

作者： Hong-liang Fan Ai-min Zhao Qing-chun Li Hui guo jian-guo he Engineering Research Institute University of Science and Technology Beijing Beijing Institute of Technology Press Beijing Institute of Technology School of Materials Science and Engineering Liaoning University of Technology School of Materials Science and Engineering Tsinghua University

The effects of ausforming strain on bainite transformation in high-carbon low-alloy nanobainite steel were investigated using a Gleeble 3500 thermomechanical simulator machine. The bainite transformation speed at 300°C was found to be accelerated by ausforming at 300, 600, and 700°C under applied strains ranging from 10% to 50% followed by isothermal transformation at 300°C. The ausformed bainite volume fraction varied with the ausforming strain because of the mechanical stabilization of the deformed austenite. Ausforming at low temperatures not only enhanced the bainite ferrite volume fraction but also refined the microstructure substantially. Although the amount of bainite ferrite might have been reduced with increasing strain, the microstructures were refined by ausforming. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin heidelberg.

关键词： Alloy steel Bainite Carbon Enzyme kinetics Ferrite Microstructure Nanostructured materials Phase transitions Strain Volume fraction

Effects of sediment particle morphology on adsorption of phosphorus elements

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International Journal of Sediment Research 2013年第2期28卷 246-253页

作者： Hong-wei FANG Ming-hong CheN Zhi-he CheN Hui-ming ZHAO guo-jian he Department of Hydraulic Engineering the State Key Laboratory of Hydro Science and EngineeringTsinghua University College of Water Resources and Civil Engineering China Agricultural University Department of Water Resources and Environment Sun Yat-sen University

Sediment particle surface morphology affects phosphorus *** paper studied the phosphorus adsorption on sediment particle by using a Scanning Electron Microscope(SEM) and an Energy Dispersive X-ray Spectroscopy (EDS).Sediment samples from the Yangtze,Yellow and Yongding rivers in China were chosen to measure the particle surface morphology,surface gray scale and element distribution *** samples were firstly cleaned and put into phosphate solution for *** the Langmuir equation and Freundlich equation were used for descriptions of adsorption-desorption isotherms for *** were then dried and *** results show that the adsorption of phosphorus depends on the surface morphology of *** exists mostly in the ridges and channels,while a few exist in the slopes,and casually in the peaks,passes and pits.

关键词： Surface morphology Scanning electron microscope Adsorption Element distribution

Mandarin fish von Hippel-Lindau protein regulates the NF-κB signaling pathway via interaction with IκB to promote fish ranavirus replication

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Zoological Research 2024年第5期45卷 990-1000页

作者： Zhi-Min Li Xiao-Wei Qin Qi Zhang jian he Min-Cong Liang Chuan-Rui Li Yang Yu Weng-Hui Liu Shao-Ping Weng jian-guo he Chang-Jun guo School of Marine Sciences State Key Laboratory for BiocontrolSouthern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Guangdong Province Key Laboratory of Aquatic Economic Animals&Guangdong Provincial Observation and Research Station for Marine Ranching of the Lingdingyang BaySun Yat-sen UniversityGuangzhouGuangdong 510275China Guangdong Laboratory for Lingnan Modern Agriculture South China Agricultural UniversityGuangzhouGuangdong 510640China

The von Hippel-Lindau tumor suppressor protein(VHL),an E3 ubiquitin ligase,functions as a critical regulator of the oxygen-sensing pathway for targeting hypoxia-inducible *** evidence suggests that mammalian VHL may also be critical to the NF-κB signaling pathway,although the specific molecular mechanisms remain ***,the roles of mandarin fish(Siniperca chuatsi)VHL(scVHL)in the NF-κB signaling pathway and mandarin fish ranavirus(MRV)replication were *** transcription of scVHL was induced by immune stimulation and MRV infection,indicating a potential role in innate ***-luciferase reporter gene assays and reverse transcription quantitative PCR(RT-qPCR)results demonstrated that scVHL evoked and positively regulated the NF-κB signaling *** with NF-κB signaling pathway inhibitors indicated that the role of scVHL may be mediated through scIKKα,scIKKβ,scIκBα,or ***-immunoprecipitation(Co-IP)analysis identified scIκBαas a novel target protein of ***,scVHL targeted scIκBαto catalyze the formation of K63-linked polyubiquitin chains to activate the NF-κB signaling *** MRV infection,NF-κB signaling remained activated,which,in turn,promoted MRV *** findings suggest that scVHL not only positively regulates NF-κB but also significantly enhances MRV *** study reveals a novel function of scVHL in NF-κB signaling and viral infection in fish.

关键词： VHL NF-κB IκBα Ranavirus Mandarin fish

Microstructure,crystallography and nucleation mechanism of NANOBAIN steel

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International Journal of Minerals,Metallurgy and Materials 2013年第12期20卷 1155-1163页

作者： Yao Huang Ai-min Zhao jian-guo he Xiao-pei Wang Zhi-gang Wang Liang Qi Metallurgy Engineering Research Institute University of Science and Technology Beijing School of Material Science and Engineering Jiangxi University of Science and Technology

The microstructure of bainite ferrite in NANOBAIN steel transformed at different temperatures was investigated by scanning electron microscopy, transmission electron microscopy, electron back-scattered diffraction, and vickers hardness tester in detail. It is found that the average width of bainitic ferrite （BF） plates can be refined to be thinner with the reduction of temperature （473-573 K）, and the bainitic ferrite plates can reach up to 20-74 nm at 473 K. Crystallographic analysis reveals that the bainitic ferrite laths are close to the Nishiyama-Wasserman orientation relationship with their parent austenite. Temperature shows a significant effect on the variant selection, and a decrease in temperature generally weakens the variant selection. Thermodynamic analyses indicates that the Lacher, Fowler and Guggenheim （LFG） model is more suitable than the Kaufman, Radcliffe and Cohen （KRC） model dealing with NANOBAIN steel at a low temperature range. The free energy change △G^γ→BF is about -1500 ***^-1 at 473 K, which indicates that nucleation in NANOBAIN steel is the shear mechanism. Finally, the formation of carbon poor regions is thermodynamically possible, and the existence of carbon poor regions can greatly increase the possibility of the shear mechanism.

关键词： nanostructured materials high strength steel bainitic transformations microstructure crystallography nucleation

Effect of Nb on Microstructure and Mechanical Properties in Non-magnetic High Manganese Steel

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Journal of Iron and Steel Research International 2014年第6期21卷 600-605页

作者： Jia-li CAO Ai-min ZHAO Ji-xiong LIU jian-guo he Ran DING National Engineering Research Center for Advanced Rolling Technology University of Science and Technology Beijing Beijing Laboratory of Metallic Materials and Processing for Modern Transportation Baotai Group Co. Ltd.

Microstructure and mechanical properties of two kinds of non-magnetic high manganese steels with and without Nb addition which experienced the same rolling and heating treatment were investigated by means of scan ning electron microscopy, electron back-scattered diffraction, transmission electron microscopy, X-ray diffraction and tensile test. It was found that the microstructure of the high manganese steel was refined by the Nb addition. Moreover, steel with Nb addition has a higher stacking fault energy which favors the deformation twinning, Twin ning is the most important deformation mechanism in the Nb-bearing steel. Therefore, steel with Nb addition has much higher strength and higher plasticity. The product of tensile strength and total elongation exceeds 61.8 GPa ·%. In addition, steel with Nb addition also has excellent non magnetic property.

关键词： non-magnetic high manganese steel Nb addition rolling twinning mechanical property

Biofilm effects on size gradation,drag coefficient and settling velocity of sediment particles

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International Journal of Sediment Research 2014年第4期29卷 471-480页

作者： Qian-qian SHANG Hong-wei FANG Hui-ming ZHAO guo-jian he Zheng-hui CUI Department of Hydraulic Engineering State Key Laboratory of Hydroscience and EngineeringTsinghua University Nanjing Hydraulic Research Institute China Institute of Water Resources and Hydropower Research

Sediment particles are often colonized by biofilm in a natural aquatic ecological system,especially in eutrophic water body.A series of laboratory experiments on particle size gradation,drag coefficient and settling velocity were conducted after natural sediment was colonized by biofilm for 5,10,15 and 20 *** image acquisition,particle tracking techniques of Particle Image Velocimetry and Particle Tracking Velocimetry were utilized to analyze the changes of these *** experimental results indicate that the size gradation,the drag force exerted on bio-particles,and the settling velocity of bio-particles underwent significant change due to the growth of biofilm onto the sediment *** study proposes a characteristic particle size formula and a bio-particle settling velocity formula based on the regression of experiment results,that the settling velocity is only 50%to 60%as the single particle which has the same diameter and ***,biofilm growth causes large particle which the settling velocities are approximately 10 times larger than that of primary *** results may be specifically used in the low energy reservoir or lake environment.

关键词： Sediment particle Biofilm Size gradation Drag coefficient Settling velocity

Electrical arc contour cutting based on a compound arc breaking mechanism

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Advances in Manufacturing 2022年第4期10卷 583-595页

作者： guo-jian he Lin Gu Ying-Mou Zhu Ji-Peng Chen Wan-Sheng Zhao K.P.Rajurkar State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240People’s Republic of China School of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing210037People’s Republic of China Center for Nontraditional Manufacturing Research University of Nebraska-LincolnLincolnNEUSA

Electrical arc contour cutting(EACC)is a novel high-efficiency material cutting process that applies arc plasma to perform efficient and economical contour cutting of difficult-to-cut *** to conventional electrical arc machining(EAM),this process can remove the allowance of open structures and plates in bulk mode,rather than entirely in the form of *** with existing contour cutting methods,EACC possesses the advantages of high cutting efficiency and a deep cutting ***,a compound arc breaking mechanism(CABM),which integrates hydrodynamic force and mechanical motion,has been applied to control the discharge arc column in EACC,while also strengthening the debris expelling effect in the narrow discharge *** CABM implementation conditions were studied,based on arc column distortion images captured by a high-speed camera and simulation results of the flow field and debris distribution.A set of machining experiments was designed and conducted to optimize the performance of the proposed ***,a SiC_(p)/Al metal matrix composite(MMC)space station workpiece was machined to verify the feasibility and efficiency of this process.

关键词： Electrical arc contour cutting(EACC) Electrical arc machining(EAM) Compound arc breaking mechanism(CABM) SiC_(p)/Al metal matrix composite(MMC) High efficiency

Positive effect of Mo on mechanical properties of a Ni-42W-10Co-xMo medium heavy alloy

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China Foundry 2025年第1期22卷 108-116页

作者： guo-xin Cao jian-xin Dong Yong-sheng he he jiang Fang Hao Zhi-hua Nie Teng-fei Ma Bao-quan Fu School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Xi'an Superalloy Technology Co. Ltd.Xi’an 710299China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of Air-driven Equipment Technology of Zhejiang Province Quzhou UniversityQuzhou 324000ZhejiangChina

In this study,a novel Ni-W-Co-Mo medium heavy alloy(MHA)was designed to improve its mechanical strength via Mo *** the Ni-42W-10Co-x Mo alloy series,where x represents the weight percent of Mo and varies between 0,1,2,5,and 10,the microstructure transitions from a dendritic structure to a hypo-eutectic structure as the Mo content increases from 0 to 5wt.%.Moreover,as the Mo content increases from 0 to 10wt.%,the distribution of theμ-phase shifts from being individually dispersed to forming aggregates,and its volume fraction rises from 0.5%to 7.9%.Notably,theμ-phase evolves into an eutectic microstructure,which helps in minimizing the segregation of *** change is accompanied by a substantial enhancement in mechanical properties;specifically,the compressive yield strength at room temperature increases from 350 MPa to 646 MPa,indicating a significant 85%***,the microhardness increases from 230 HV to 304 *** dynamics simulations further reveal that the strengthening mechanism of Ni-42W-10Co-x Mo alloys is Mo-induced solid solution strengthening and precipitation strengthening.

关键词： medium-heavy alloys Ni-based alloy mechanical properties solid solution strengthening precipitation strengthening

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Frequent ventricular premature beats increase blood pressure variability in rats

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Acta Pharmacologica Sinica 2004年第5期25卷 3-11页

作者： Chao-yu MIAO2, Li-ping XU, jian-guo LIU, he-hui XIE, Wen-jun YUAN, Ding-feng SU2Department of Pharmacology, Second Military Medical University, Shanghai 200433, China Department of Pharmacology Second Military Medical University 上海 200433

AIM: The present study was designed to test a hypothesis that nonfatal ventricular arrhythmia such as ventricularpremature beats (VPB) is a contributing factor in the elevation of blood pressure variability (BPV). METHODS:Blood pressure (BP) and electrocardiogram were continuously recorded. The relation between VPB and BPV wasobserved under conscious state in chronic myocardial infarction (MI) rats one month after ligation of the leftcoronary artery, and further verified under anesthetized state in rat model of ventricular arrhythmia produced byacute intravenous infusion of aconitine. RESULTS: MI rats exhibited a big difference in the count and pattern ofVPB, and were divided into no VPB, occasional VPB, and frequent VPB groups. Among the three groups, therewere no differences in BP, heart period (HP), and MI size. However, BPV was markedly higher in frequent notoccasional VPB rats, and HP variability (HPV) was larger in both frequent and occasional VPB rats, when comparedwith no VPB rats. In the whole population of MI rats, BPV was positively correlated with VPB and HPV, not withBP, HP and MI size. Infusion of aconitine had no effect on BP, HP, BPV, and HPV during the period without *** VPB after several minutes of aconitine infusion induced significant increase in BPV and HPV with nochange in BP and HP. BPV was also positively correlated with VPB and HPV, not with BP and HP. hemodynamicsin aconitine-evoked ventricular tachycardia was characterized as lower BP, higher BPV, and higher ***: High BPV can be caused by frequent not occasional VPB in rats.

关键词： arrhythmia blood pressure variability heart period variability