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Effect of superheat on quality of central equiaxed grain zone of continuously cast bearing steel billet based on two-dimensional segregation ratio

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Journal of Iron and Steel Research International 2018年第1期25卷 9-18页

作者： wei Wang Zi-bing Hou yi Chang Jiang-hai Cao College of Materials Science and Engineering ChongqingUniversity Chongqing 400044 China

The quality of central equiaxed grain zone （CEGZ） of GCr15 bearing steel billets was investigated at different superheats （20, 25 and 35 ℃ by experimental observations and a finite element model in order to optimize superheat in continuous casting process. Several GCrl5 billets were collected from the continuous casting shop, and the same CEGZ was chosen for comparison of internal quality of GCrl5 billets. Considering the limitation of segregation index at some points, two- dimensional segregation ratio in CEGZ was introduced. Firstly, the segregation ratio and the area of center large dark points in CEGZ obtain the minimum at 25 ℃ superheat, which indicates that the quality of CEGZ at 25 ~C superheat is improved compared with those at 20 and 35 ℃ superheats for corresponding continuously cast billets. The highest superheat and the lowest superheat are not beneficial for improving the central zone quality in the billets. Secondly, the quality of CEGZ of GCr15 billets increases with a decrease in the secondary dendrite arm spacing of CEGZ. Finally, according to the established finite element model, it is deduced that the secondary dendrite arm spacing of CEGZ is closely related to its later solidifica- tion time at solid fraction of 0.5-1.0, and the former will be decreased when decreasing the latter.

关键词： Superheat Continuously cast billet Equiaxed grain zone Segregation Solidification time

生物聚合物聚-3-羟基丁酸酯的酶法提取纯化研究

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现代化工 2025年第1期45卷 137-142页

作者：薛英茹周浩周卫强刘海军李义李非河北工业大学化工学院天津300401 中粮营养健康研究院有限公司北京102209 吉林中粮生化有限公司玉米深加工国家工程研究中心吉林长春130033 中粮生物材料(榆树)有限公司吉林长春130401

通过酶解法从嗜盐菌发酵液中获得高纯度、高分子质量的聚-3-羟基丁酸酯(PHB),分别采用高温处理与胞壁酸酶酶解2种方法对嗜盐菌细胞进行破壁,再通过中碱性蛋白酶进一步酶解纯化。结果表明,121℃下高温处理可有效实现嗜盐菌细胞破壁,但高... 详细信息

通过酶解法从嗜盐菌发酵液中获得高纯度、高分子质量的聚-3-羟基丁酸酯(PHB),分别采用高温处理与胞壁酸酶酶解2种方法对嗜盐菌细胞进行破壁,再通过中碱性蛋白酶进一步酶解纯化。结果表明,121℃下高温处理可有效实现嗜盐菌细胞破壁,但高温环境使PHB分子质量降低了30%~40%;在50℃、pH 6条件下添加0.3%胞壁酸酶酶解60 min破壁效果最好,且分子质量可维持在10%以内;在70℃、pH 10条件下添加0.045%中碱性蛋白酶酶解60 min纯化效果最好,所得PHB纯度可达97%以上。最后与市售PHB进行对比,确认了所得PHB的化学结构及热性能。酶的特异性水解保证了PHB结构不受破坏,胞壁酸酶-中碱性蛋白酶结合酶解法可以得到高纯度、高分子质量的PHB,无需其他化学试剂辅助。

关键词：聚-3-羟基丁酸酯高温处理酶解提取纯化

Unusual Spherulitic Morphology of Poly(propylene fumarate)

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Chinese Journal of Polymer Science 2021年第4期39卷 493-500,I0007页

作者： Xiao-Yu Meng yi Li Shu-Fang Yao Xue-wei wei hai-Mu Ye Department of Materials Science and Engineering College of New Energy and MaterialsChina University of PetroleumBeijing 102249China

Spherulites are the most common crystalline morphology and thus the visual expression of crystal structures for *** diversified patterns have provided intuitive morphology probes for various crystallization behaviors,while the correlations between them are still needed to be *** this work,the complicated spherulitic morphology of poly(propylene fumarate)(PPF),which is sensitive to crystallization temperature,is *** melt,respectively,crystallizes into rough spherulites,regularly banded spherulites,and spherulites containing both two kinds of morphology at low,high,and mediate *** systematically assaying,it is clear that the growth axis along the radial direction changes from a-axis to b-axis as the crystallization temperature increases,which leads to the formation of unique crystallization-temperature-dependent *** on detailed characterization of Fourier transform infrared spectroscopy,the packing state of the specific hydrogen bonds of"C=C-H…O=C-C=C"in PPF crystal lattices is determined,and furthermore,the mechanism for temperature-dependent selection of growth axes for PPF spherulites in melt is reasonably speculated.

关键词： Spherulite Crystallization Growth axis Hydrogen bond

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基于IMU的FAST巡检定位系统研究

天文学报 2025年第1期66卷 94-103页

作者：胡玮于东俊孙京海中国科学院国家天文台北京100101 中国科学院大学北京100049

日常巡检是500m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)运行和维护中的重要工作. FAST部件众多,巡检过程中存在工作量大、寻找部件费时费力的问题.实现巡检定位,可以引导维护人员快速到达故障... 详细信息

日常巡检是500m口径球面射电望远镜(Five-hundred-meter Aperture Spherical radio Telescope,FAST)运行和维护中的重要工作. FAST部件众多,巡检过程中存在工作量大、寻找部件费时费力的问题.实现巡检定位,可以引导维护人员快速到达故障点,对提高巡检效率,保障望远镜正常运行有重要意义.考虑到反射面对卫星信号存在遮挡,采用惯性导航的方式,基于双足脚绑IMU(Inertial Measurement Unit),设计了1套步行导航算法.算法沿用零速修正框架,融合双足信息,并结合磁场信息修正航向误差.在规则轨迹中测试了算法有效性,水平定位误差在行走距离的3%以内.在巡检现场的不规则轨迹中,结合沿途标志点,水平定位误差小于11 m,能够满足日常巡检定位的需要和支撑后续巡检定位系统的实用化.

关键词：望远镜:500 m口径球面射电望远镜技术:步行导航仪器:脚绑惯性测量单元方法:卡尔曼滤波

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Osmolyte Effects on the Unfolding Pathway ofβ-Lactoglobulin

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Chinese Physics Letters 2013年第10期30卷 221-224页

作者： MENG wei PAN hai QIN Meng CAO yi WANG wei National Laboratory of Solid State Microstructure and Department of Physics Nanjing UniversityNanjing 210093

There are large amounts of osmolytes inside cells,which impact many physiological processes by complicated *** osmolyte effects on the stability and folding of proteins have been studied in detail using simple two-state folding ***,many important functional proteins fold in complex pathways involving various *** is known about the osmolyte effects on the folding and unfolding of these *** is noted thatβ-lactoglobulin(BLG)is an example of such proteins,whose unfolding involves an obvious intermediate *** equilibrium chemical denaturation and stopped-flow kinetics,we investigate the unfolding of BLG in the presence of different osmolytes,e.g.,glycerol,ethylene glycol(EG)and poly(ethylene glycol)400(PEG400).It is found that all these osmolytes can stabilize the unfolding intermediate by modulating the relative unfolding kinetics of the native and the intermediate *** stabilization effects are similar for EG and PEG400 but distinct for *** the unfolding intermediates of many proteins are directly related to protein misfolding diseases,evaluation of the osmolyte effects for the unfolding of these proteins in vitro should be beneficial for the understanding of the occurrence of the related diseases in vivo.

关键词： state kinetics stabilization

Protecting lithium metal anode in all-solid-state batteries with a composite electrolyte

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Rare Metals 2021年第2期40卷 409-416页

作者： Wen-Qing wei Bing-Qiang Liu yi-Qiang Gan hai-Jian Ma Da-wei Cui School of Mechanical-electronic and Vehicle Engineering Weifang UniversityWeifang261061China Department of Chemical and Materials Engineering the University of AucklandAuckland1142New Zealand College of Mechanical and Electronic Engineering Shandong University of Science and TechnologyQingdao266590China

The volume of the metallic lithium anode in allsolid-state Li metal batteries increases significantly due to the lithium dendrite formation during the battery cycling,and the rough surface of lithium metal also reduces Li-ion transport in Li/electrolyte *** this work,we developed a solid polymer composite by adding the lowcost Si_(3)N_(4)particles to protect the lithium anode in allsolid-state *** Fourier transform infrared spectroscopy(FTIR)data show that the surface of 10 wt%Si_(3)N_(4)particles interacts with the polyethylene oxide(PEO)and lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)salt;the interaction restricts the anion mobility and improves the ionic conductivity(1×10^(-4)S·cm^(-1))and lithium-ion transference number(0.28)of the composite *** lithium metal anode is well protected by the composite electrolyte in all-solid-state cells,including symmetric and Li/LiFePO_(4)*** lithium dendrite growth suppression by this composite electrolyte indicates the possible application of these low-cost composite electrolytes for lithium metal protection.

关键词： Lithium metal anode Lithium dendrite growth Composite electrolyte Symmetric cell

Liutex-based vortex control with implications for cavitation suppression

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Journal of Hydrodynamics 2021年第1期33卷 74-85页

作者： yi-qian Wang hai-dong Yu wei-wen Zhao De-cheng Wan School of Mathematical Science Soochow UniversitySuzhou 215006China School of Aerospace Engineering Tsinghua UniversityBeijing 100084China Computational Marine Hydrodynamics Lab(CMHL) State Key Laboratory of Ocean EngineeringSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Viewed as sinews and muscles of fluid motion,coherent vortical structures with their interactions are key to understanding the flow *** upon this observation,we explore the possibility of efficient flow control by directly manipulating vortices numerically inside the flow field based on the vortex definition and identification system of *** objective is twofold:(1)to study the vortex dynamics,for example,by observing the response of the flow to strengthening or weakening of certain vortices,and(2)to obtain efficient vortex-based control strategies which might lead us to practical *** the present numerical study,the manipulating of vortices is achieved by introducing additional source(force)terms to the Navier-Stokes equations,which hereafter will be collectively called Liutex force field *** including controlling the rotation strength and centripetal force of particular vortices are detailed in a flow past a cylinder with different control purposes at Reynolds number of *** examples are provided with a cavitating flow around two-dimensional Clark-Y hydrofoil,with particular interests on cavitation *** is illustrated particular vortex with cavitation encircled could be effectively suppressed.

关键词： Vortex dynamics Liutex vector flow control cavitation Introduction

Ultrafine grained metastable Ti6Al4V5Cu alloy with high strength and excellent low-cycle fatigue property

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Journal of Materials Science & Technology 2022年第34期129卷 240-250页

作者： wei Song hai Wang yi Li Shuyuan Zhang Ling Ren Ke Yang Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

The insufficient low-cycle fatigue properties of titanium alloys under cyclic heavy loading are regarded as a challenge for their security in service. In recent years, a large number of studies have found that the transformation induced plasticity(TRIP) effect could hinder the propagation of fatigue cracks, which significantly improved the low-cycle fatigue properties of titanium alloys. However, the coarse β-phase grains and the soft phase transformation product α phase in TRIP titanium alloys impair their tensile strength, which restrict their applications in engineering. To this end, a Ti6Al4V5Cu alloy with TRIP effect was developed in this work. It was proposed to use the mutual restraint between the α and βphases in the material to refine the grains, and through composition optimization, the phase transformation product would be the α’ phase, which has a higher strength than the α phase. Thus, the strength of the Ti6Al4V5Cu alloy can be improved. The results showed that the tensile strength and elongation of the TRIP Ti6Al4V5Cu alloy was 1286 MPa and 22%, which was 23.7% and 46.7% higher than that of the traditional Ti6Al4V alloy, respectively. Besides, under the same strain amplitude, the fatigue life of the Ti6Al4V5Cu alloy was 2–5 times longer than that of the Ti6Al4V alloy. Furthermore, we clarified the mechanisms of improving the tensile strength and fatigue properties of the Ti6Al4V5Cu alloy, which would lay a research foundation for the development of high-performance titanium alloys.

关键词： Transformation induced plasticity Ti alloys Low-cycle fatigue Work hardening Crack propagation

Tribological and Corrosion Properties of the CoCrAlYTaSiC-xCNTs Coatings Deposited by Laser Cladding

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 726-738页

作者： hai Zhao yi Ding wei Gao Bo Yu Jinghui Li Mingya Zhang School of Material Science and Engineering Anhui University of TechnologyMaanshan243002China Maanshan Iron&Steel Co. LtdMaanshan243000China Applied Technology Research Institute Jiujiang Vocational UniversityJiujiang332000China School of Metallurgical Engineering Anhui University of TechnologyMaanshan243002China

The MCrAlY coating has been potential candidate for the parts applied in friction and corrosion conditions, and CNTs (carbon nanotubes) are expected to improve the service performance of coatings owing to high lubrication and low chemical reactivity. In this work, a systematic investigation on the tribological and corrosion properties of CoCrAlYTaSiC-xCNTs coatings deposited by laser melting was analyzed. Results showed that the coatings had good-quality without typical metallurgical defects. The CNTs addition homogenized and refined the microstructure of coating, and also improved the tribological and corrosion properties. As the CNTs content changed from 0 to 4 wt%, the wear rate of coating decreased from 16.23 × 10^(-3) to 7.58 × 10^(-3) mg m^(−1), the jcorr of coating decreased from 4.13 × 10^(-4) to 1.23 × 10^(-4) A cm^(−2), and the Rct values increased from 12.69 to 25.07 Ω cm2.

关键词： MCrAlY coating Laser melting deposition Friction Electrochemical corrosion