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Interstitial Solution Carbon Concentration and Defects of Ti+Nb ULC-BH Steel by Internal Friction and Positron Annihilation Methods

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Journal of Iron and Steel Research International 2014年第1期21卷 91-97页

作者： Ji-ping CHEN Yong-lin kang School of Metallurgical Engineering Key Laboratory of Metals and Processing of Anhui Province Anhui University of Technology School of Materials Science and Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology Beijing

The interstitial solution carbon concentration and defects in continuously annealed Ti＋Nb bearing ULC- BH （ultra-low carbon bake hardening） steel samples are investigated by multi-functional internal friction apparatus, positron annihilation lifetime spectroscopy （PALS） and coincidence Doppler broadening spectroscopy （CDBS）. The relationship of internal friction peaks, interstitial solution carbon concentrations and movable dislocations in the sam- ples under different conditions is analyzed. A correlation of lifetime component v~ values with interstitial solution car- bon concentrations in the samples for different continuous annealing processes is established, while a correlation of li- fetime component r2 values with multi-vacancies, vacancy clusters, microvoids and other types of defects for various continuous annealing processes is also demonstrated. Furthermore, the average lifetime results illustrate the overall defect densities for various continuous annealing processes. The CDBS analysis reflects the chemical surroundings of the defects at the annihilation sites and reveals that the peak heights of the ratio curves relate to the total number of defects such as interstitial carbon atoms, dislocations, vacancies and other types of defects. The results show that in- ternal friction, PALS and CDBS are effective techniques to identify and characterize the interstitial solution carbon concentration, multi-vacancies, vacancy clusters, microvoids and other types of microscopic defects in annealed Ti＋ Nb bearing ULC-BH steel.

关键词： ULC-BH steels internal frictions positron annihilation lifetimes coincidence Doppler broadening

Influence of coating and dew point on hearth roll pickup

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Journal of Iron and Steel Research International 2019年第6期26卷 647-652页

作者： Xiao-fei Zheng Yong-lin kang Jian Zhou School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Shougang Jingtang Iron and Steel United Co. Ltd. Tangshan 063200 Hebei China

Thermal spray coatings have been widely used on hearth rolls in a continuous annealing line to improve steel sheet quality and prolong the roll service life. One of the common defects formed on a working hearth roll is the oxide pickup. The most common cause of the pickup formation is that the active Mn oxide reacts with coating. The potentials of two different coatings, CoCrAlYTa-Al2O3 (No. 1) and CoCrYNi-Y2O3 (No. 2), to duplicate pickups by reacting with Fe and Mn oxides were studied. There are three stages during pickup producing and growing. No. 2 coating effectively reduced the corrosion of Mn oxide. The characterization and modification of the surface oxide formed can be changed with different dew points. The results indicate that the dew point from — 53 to — 10 ℃ can change the depth of Mn oxide, such that an alteration can prevent the first stage and second stage and is good for preventing the pickup growing.

关键词： Pickup Coating Dew point Surface oxide Hearth roll

Oxygen Penetration Through Full-Thickness Skin by Oxygen-Releasing Sutures for Skin Graft Transplantation

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Engineering 2023年第10期29卷 83-94页

作者： Wenjing Zai Yunong Yuan lin kang Jialong Xu Yiqiao Hu Lifeng kang Jinhui Wu State Key Laboratory of Pharmaceutical Biotechnology Medical SchoolNanjing UniversityNanjing 210093China School of Pharmacy Faculty of Medicine and HealthUniversity of SydneySydneyNSW 2006Australia School of Biomedical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Chemistry and Biomedicine Innovation Center Nanjing UniversityNanjing 210023China Jiangsu Provincial Key Laboratory for Nano Technology Nanjing UniversityNanjing 210093China Jiangsu Food&Pharmaceutical Science College Huai’an 223003China

The transplantation of full-thickness skin grafts(FTSGs)is important for reconstructing skin barrier and promoting wound *** oxygen supply is closely related to the success of skin ***,full-thickness oxygen delivery is limited by the poor oxygen permeability of ***-releasing sutures(O_(2)sutures)were developed to facilitate oxygen penetration through full-thickness *** O_(2)sutures delivered 100 times more oxygen than topical gaseous oxygen therapy at a 15 mm depth in the skin *** extreme hypoxia(linical applications to increase the success rate of full-thickness skin transplantation.

关键词： Wound Skin graft transplantation Oxygen-releasing sutures Full-thickness oxygen delivery

Topological Wannier Cycles for the Bulk and Edges

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Chinese Physics Letters 2022年第8期39卷 39-46页

作者： Ze-lin Kong Zhi-kang lin Jian-Hua Jiang School of Physical Science and Technology and Collaborative Innovation Center of Suzhou Nano Science and TechnologySoochow UniversitySuzhou 215006China Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Ministry of EducationSoochow UniversitySuzhou 215006China

Topological materials are often characterized by unique edge states which are in turn used to detect different topological phases in ***,with the discovery of various higher-order topological insulators,such spectral topological characteristics are extended from edge states to corner ***,the chiral symmetry protecting the corner states is often broken in genuine materials,leading to vulnerable corner states even when the higher-order topological numbers remain quantized and ***,we show that a local artificial gauge flux can serve as a robust probe of the Wannier type higher-order topological insulators,which is effective even when the chiral symmetry is *** resultant observable signature is the emergence of the cyclic spectral flows traversing one or multiple band *** spectral flows are associated with the local modes bound to the artificial gauge *** phenomenon is essentially due to the cyclic transformation of the Wannier orbitals when the local gauge flux acts on *** extend topological Wannier cycles to systems with C_(2)and C_(3)symmetries and show that they can probe both the bulk and the edge Wannier centers,yielding rich topological phenomena.

关键词： topological gauge Wannier

Effects of Nb on the microstructure and mechanical properties of 38MnB5 steel

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International Journal of Minerals,Metallurgy and Materials 2018年第10期25卷 1181-1190页

作者： Li lin Bao-shun Li Guo-ming Zhu Yong-lin kang Ren-dong Liu School of Material Science and Engineering University of Science and Technology BeijingBeijing 100083China Ansteel Technology Center Anshan 114009China

The effects of the microalloying element niobium(Nb) on the microstructure and mechanical properties of the hot stamped steel 38 Mn B5 were investigated. The impact of Nb addition on the microstructure was studied through scanning electron microscopy(SEM), transmission electron microscopy(TEM), and X-ray diffraction(XRD). The experimental results indicated that the microstructures of the steel containing Nb were finer than those of the steel without Nb. Moreover, Nb mainly presented as a second-phase particle in 38MnB5 steel, and the particles included Nb carbonitrides. In addition, the tensile strength and elongation of the hot rolled and hot stamped steels were also measured, and they demonstrated that the appropriate addition of Nb was beneficial to the mechanical properties of 38 MnB5. Under the same conditions, the tensile strength of 38 MnB5 Nb was higher than that of 38 MnB5, which increased from 2011 to 2179 MPa. The yield strength also increased from 1316 to 1476 MPa, and the elongation increased from 5.92% to 6.64%. Overall, Nb had a positive effect on the performance of the hot stamped steel.

关键词： hot stamping steel CCT curve microstructure mechanical properties precipitation

Membrane enhanced COD degradation of pulp wastewater using Cu_2O/H_2O_2 heterogeneous Fenton process

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Chinese Journal of Chemical Engineering 2018年第9期26卷 1896-1903页

作者： Hongjia Zhou lin kang Ming Zhou Zhaoxiang Zhong Weihong Xing State Key Laboratory of Materials-Oriented Chemical Engineering National Engineering Research Center for Special Separation Membrane Nanjing Tech University

Both activity and stability of the catalyst can be improved in heterogeneous Fenton reaction,in particular,with no limitation for the working p H and no production of the *** this work,a combination of catalyst Cu_2O and pore-channel-dispersed H_2O_2is proposed to treat the pulp *** degree of CODs in the wastewater was up to 77%in the ceramic membrane reactor using Cu_2O powder(2.0 g·L^(-1))and membranefeeding H_2O_2(0.8 ml·L^(-1))within 60 *** of·OH radical formation in the advanced oxidation process was analyzed with a fluorescent *** efficiency of H_2O_2was successfully enhanced by 10%with the membrane *** on,the catalyst recyclability was evaluated in a five-cycle *** concentration of copper ions being dissolved in the treated water was monitored with *** Cu_2O/H_2O_2(membrane)treatment the effluent is qualified to discharge with COD concentration lower than 15 mg·L^(-1)with regard to the national standard GB25467-2010.

关键词： Pulp wastewater Heterogeneous Fenton Membrane Cu2O Advanced oxidation

Stress-strain partitioning analysis of constituent phases in dual phase steel based on the modified law of mixture

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International Journal of Minerals,Metallurgy and Materials 2009年第4期16卷 393-398页

作者： Shuang Kuang Yong-lin kang Hao Yu Ren-dong Liu School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Technology Center Anshan Iron ＆ Steel Group Corporation Anshan 114001 China

A more accurate estimation of stress-strain relationships for martensite and ferrite was developed, and the modified law of mixture was used to investigate the stress-strain partitioning of constituent phases in dual phase （DP） steels with two different martensite volume fractions. The results show that there exist great differences in the stress-strain contribution of martensite and ferrite to DP steel. The stress-strain partitioning coefficient is not constant in the whole strain range, but decreases with increasing the true strain of DP steel. The softening effect caused by the dilution of carbon concentration in martensite with the increase of martensite volume fraction has great influence on the strain contribution of martensite. The strain ratio of ferrite to martensite almost linearly increases with increasing the true strain of DP steel when the martensite volume fraction is 22%, because martensite always keeps elastic. But the strain ratio of ferrite to martensite varies indistinctively with the further increase in true strain of DP steel above 0.034 when the martensite volume fraction is 50%, because plastic deformation happens in martensite. The stress ratio ofmartensite to ferrite decreases monotonously with increasing the true strain of DP steel whether the martensite volume fraction is 22% or 50%.

关键词： stress and strain partitioning dual phase steel ferrite martensite

Effect of continuous annealing parameters on the mechanical properties and microstructures of a cold rolled dual phase steel

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International Journal of Minerals,Metallurgy and Materials 2009年第2期16卷 159-164页

A cold rolled dual phase （DP） steel with the C-Si-Mn alloy system was trial-produced in the laboratory, utilizing a Gleeble-3800 thermal simulator. The effects of continuous annealing parameters on the mechanical properties and microstructures of the DP steel were investigated by mechanical testing and microstructure observation. The results show that soaking between 760 and 820℃ for more than 80 s, rapid cooling at the rate of more than 30℃/s from the quenching temperature between 620 and 680℃, and overaging lower than 300℃ are beneficial for the mechanical properties of DP steels. An appropriate proportion of the two phases is one of the key factors for the favorable properties of DP steels. If the volume fraction of martensite and, thereby, free dislocations are deficient, the tensile strength and n value of DP steels will decrease, whereas, the yield strength will increase. But if the volume fraction of martensite is excessive to make it become a dominant phase, the yield and tensile strength will increase, whereas, the elongation will decrease obviously. When rapid cooling rate is not fast enough, pearlite or cementite will appear, which will degrade the mechanical properties. Even though martensite is sufficient, if it is decomposed in high temperature tempering, the properties will he unsatisfied.

关键词： austenization intercritical annealing dual phase steel cold rolling diffusion

Scaling laws for the intermittent swimming performance of a flexible plate at low Reynolds number

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Journal of Hydrodynamics 2023年第4期35卷 803-810页

作者： lin-lin kang Shi-xian Gong Xi-Yun Lu Wei-cheng Cui Di-xia Fan Key Laboratory of Coastal Environment and Resources of Zhejiang Province School of EngineeringWestlake UniversityHangzhou310030China Department of Modern Mechanics University of Science and Technology of ChinaHefei230026China

Many species of fish and birds travel in intermittent style,yet the combined influence of intermittency and other body kinematics on the hydrodynamics of a self-propelled swimmer is not fully *** formulating a reduced-order dynamical model for intermittent swimming,we uncover scaling laws that link the propulsive performance(cursing Reynolds number Rec,thrust T̄,input power P̄and cost of transport COT to body kinematics(duty cycle DC,flapping Reynolds number Ref).By comparing the derived scaling laws with the data from several previous studies and our numerical simulation,we demonstrate the validity of the *** addition,we found that Re_(c),T̄,P̄and COT all increase with the increase of DC,*** model also reveals that the intermittent swimming may not be inherently more energy efficient than continuous swimming,depending on the ratio of drag coefficients between active bursting and coasting.

关键词： Propulsion intermittent swimming scaling law