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Work Hardening Behavior of 1020 Steel During Cold-Beating Simulation

Chinese Journal of Mechanical Engineering 2017年第2期30卷 321-331页

作者： Fengkui CUI Yuanfei LING Jinxue XUE Jia liu yuhui liu Yan LI School of Mechatronics Engineering Henan University ofScience and TechnologyLuoyang 471003China Collaborative Innovation Center of Machinery Equipment Advanced Manufacturing of Henan Province Henan University of Science and TechnologyLuoyang 471003China School of Mechanical and Precision Instrument Engineering Xi'an University of Technology Xi'an 710048China

The present research of cold-beating formation mainly focused on roller design and manufacture, kinematics, constitutive relation, metal flow law, thermo-mechanical coupling, surface micro-topography and microstructure evolution. However, the research on surface quality and performance of workpieces in the process of cold-beating is rare. Cold-beating simulation experiment of 1020 steel is conducted at room temperature and strain rates ranging from 2000 to 4000 s^-1 base on the law of plastic forming. According to the experimental data, the model of strain hardening of 1020 steel is established, Scanning Electron Microscopy（SEM） is conducted, the mechanism of the work hardening of 1020 steel is clarified by analyzing microstructure variation of 1020 steel. It is found that the strain rate hardening effect of 1020 steel is stronger than the softening effect induced by increasing temperatures, the process of simulation cold-beating cause the grain shape of 1020 steel significant change and microstructure elongate significantly to form a fibrous tis- sue parallel to the direction of deformation, the higher strain rate, the more obvious grain refinement and the more hardening effect. Additionally, the change law of the work hardening rate is investigated, the relationship between dislocation density and strain, the relationship between work hardening rate and dislocation density is obtained. Results show that the change trend of the work hardening rate of 1020 steel is divided into two stages, the work hardening rate decreases dramatically in the first stage and slowly decreases in the second stage, finally tending toward zero. Dislocation density increases with increasing strain and strain rate, work hardening rate decreases with increasing dislocation density. The research results provide the basis for solving the problem of improving the surface quality and performance of workpieces under cold-beating formation of 1020 steel.

关键词： 1020 steel Cold·beating Work hardening Grain Dislocation density

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Absorbing Interface Conditions for the Simulation of Wave Propagation on Non-Uniform Meshes

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Numerical Mathematics(Theory,Methods and Applications) 2023年第2期16卷 433-452页

作者： Changshi Li yuhui liu Fengru Wang Jerry Zhijian Yang Cheng Yuan Institute of Artificial Intelligence School of Computer ScienceWuhan UniversityWuhan 430072P.R.China School of Mathematics and Statistics Wuhan UniversityWuhan 430072P.R.China Hubei Key Laboratory of Computational Science Wuhan UniversityWuhan 430072P.R.China

We proposed absorbing interface conditions for the simulation of linear wave propagation on non-uniform *** on the superposition principle of second-order linear wave equations,we decompose the interface condition problem into two subproblems around the interface:for the first one the conventional artificial absorbing boundary conditions is applied,while for the second one,the local analytic solutions can be *** proposed interface conditions permit a two-way transmission of low-frequency waves across mesh interfaces which can be supported by both coarse and fine meshes,and perform a one-way absorption of high-frequency waves which can only be supported by fine meshes when they travel from fine mesh regions to coarse *** examples are presented to illustrate the efficiency of the proposed absorbing interface conditions.

关键词： Local time step non-uniform mesh absorbing interface condition

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Bio-inspired Attachment Mechanism of Dynastes Hercules:Vertical Climbing for On-Orbit Assembly Legged Robots

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Journal of Bionic Engineering 2024年第1期21卷 137-148页

作者： Yuetian Shi Xuyan Hou Zhonglai Na Jie Zhou Nan Yu Song liu Linbo Xin Guowei Gao yuhui liu School of Mechatronics Engineering Harbin Institute of TechnologyHarbin 150001China

With the increasing size of space facilities,on-orbit assembly requires robots to move on different heights of *** paper proposes a bio-inspired attachment mechanism for robot feet to enable climbing on different heights of *** by the attachment and grasping abilities of Dynastes Hercules,we utilize its foot microstructures,such as microhooks and setae,to achieve efficient contact and firm grip with the *** morphology and arrangement of these structures can inspire the design of robot feet to improve their grasping and stability *** study the biological structure of Dynastes Hercules,design and optimize the bio-inspired structure,analyze the influence of various factors from theoretical and experimental perspectives,and verify the feasibility of the scheme through *** propose an ideal climbing strategy that provides useful reference for robot applications in ***,the influence laws of various factors in this paper can be applied to robot foot design to improve their operation ability and stability performance in the space *** bio-inspired mechanism can improve robot working range and efficiency,which is critical for on-orbit assemblyin space.

关键词： Space assembly robot Truss climbing Bionic structure Dynastes Hercules tarsus

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Ultrathin hexagonal boron nitride as a van der Waals,force initiator activated graphene for engineering efficient non-metal electrocatalysts of Li-CO_(2) battery

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Nano Research 2022年第2期15卷 1171-1177页

作者： Zemin Sun Di Wang liu Lin yuhui liu Mengwei Yuan Caiyun Nan Huifeng Li Genban Sun Xiaojing Yang Beijing Key Laboratory of Energy Conversion and Storage Materials Institution College of ChemistryBeijing Normal UniversityBeijing 100875China

Reasonably regulating electronic coupling to promote charge transfer and exciton separation has been regarded a promising approach in *** material engineering of van der Waals heterojunction(vdWsH)based on two-dimensional(2D)materials would be a potential way to optimize the as-prepared extrinsic physicochemical ***,it was still an almost uncultivated land waiting for exploration in ***,we introduced the inert h-boron nitride(h-BN)in non-metal reduced graphene oxide(GN)catalysts and constructed BN-GN *** theoretical calculation demonstrated that the h-BN can effectively modify the electronic properties of *** the introduction of h-BN,the BN-GN vdWsH can obviously enhance the catalytic activity of Li-CO_(2) *** existence of BN-GN vdWsH can reduce the overpotential more than 700 mV compared with reduced graphene oxide during the CO_(2) reduction reaction(CO_(2)RR)and CO_(2) evolution reaction(CO_(2)ER),and it extended cyclic stability more than three times,which was one structure design made it work as a high efficient electrocatalyst,catalytic materials.

关键词： van der Waals heterojunction(vdWsH) Li-CO_(2)battery boron nitride-graphene oxide vdWsH non-metal catalysis

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U(VI) adsorption behavior onto polypyrrole coated 3R-MoS2 nanosheets prepared with the molten salt electrolysis method

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International Journal of Minerals,Metallurgy and Materials 2022年第3期29卷 479-489页

作者： yuhui liu Meng Tang Shuang Zhang Yuling Lin Yingcai Wang Youqun Wang Ying Dai Xiaohong Cao Zhibin Zhang Yunhai liu State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China School of Nuclear Science and Engineering East China University of TechnologyNanchang 330013China

To improve the separation capacity of uranium in aqueous solutions, 3R-MoS2 nanosheets were prepared with molten salt electro- lysis and further modified with polypyrrole (PPy) to synthesize a hybrid nanoadsorbent (PPy/3R-MoS2). The preparation conditions of PPy/3R- MoS2 were investigated and the obtained nanosheets were characterized with scanning electron microscope (SEM), high resolution transmis- sion electron microscope (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectro- scopy (XPS). The results showed that PPy/3R-MoS2 exhibited enhanced adsorption capacity toward U(VI) compared to pure 3R-MoS2 and PPy;the maximum adsorption was 200.4 mg/g. The adsorption mechanism was elucidated with XPS and FTIR: (1) negatively charged PPy/3R-MoS2 nanosheets attracted by an electrostatic interaction;(2) exposed C, N, Mo, and S atoms complexed with U(VI) through co- ordination;(3) Mo in the complex partly reduced the adsorbed U(VI) to U(IV), which further regenerated the adsorption point and continu- ously adsorbed U(VI). The design of the PPy/3R-MoS2 composite with a high adsorption capacity and chemical stability provides a new direc- tion for the removal of radionuclide.

关键词： molten salt electrolysis 3R-MoS2 nanosheets polypyrrole modification adsorption uranium

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Synergy of photocatalytic reduction and adsorption for boosting uranium removal with PMo_(12)/UiO-66 heterojunction

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Chinese Chemical Letters 2022年第7期33卷 3577-3580页

作者： Zhibin Zhang Zifan Li Zhimin Dong Fengtao Yu Yingcai Wang Youqun Wang Xiaohong Cao yuhui liu Yunhai liu Jiangxi Province Key Laboratory of Synthetic Chemistry East China University of TechnologyNanchang 330013China State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China

In this work,we proposed a new U(Ⅵ)removal strategy combining adsorption and photocatalytic reduction by the PMo_(12)/UiO-66 *** PMo_(12)has been encapsulated in the cavities of Ui O-66 by a one-step hydrothermal method,and the PMo_(12)/UiO-66 exhibited high adsorption capacity and photocatalytic *** maximal theoretical sorption capacity of U(Ⅵ)on 15%PMo_(12)/UiO-66 reached225.36 mg/g and the photoreduction rate of 15%PMo_(12)/UiO-66 is about thirty times as much as *** the light irradiation,the photogenerated electrons rapidly transport from UiO-66 to PMo_(12),and the photo-generated electrons could efficiently reduce the pre-enriched U(Ⅵ)to U(IV).This work provides new insights into remediation of the radioactive environment.

关键词： UiO-66 PMo12 Uranium Adsorption Photocatalytic reduction

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Discovery of antitumor diterpenoids from Casearia graveolens targeting VEGFR-2 to inhibit angiogenesis

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Chinese Journal of Natural Medicines 2024年第9期22卷 842-853页

作者： WANG Sibei liu yuhui LIANG Yue XI Yaru ZHAI Yupeng LEE Dongho XU Jing GUO Yuanqiang State Key Laboratory of Medicinal Chemical Biology College of Pharmacyand Tianjin Key Laboratory of Molecular Drug ResearchNankai UniversityTianjin 300350China State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical UniversityGuiyang 550014China Department of Plant Biotechnology College of Life Sciences and BiotechnologyKorea UniversitySeoul 02841South Korea

Eight novel clerodane diterpenoids(1-8)were isolated from the twigs of Casearia *** structures were elucidated through comprehensive nuclear magnetic resonance(NMR),high-resolution electrospray ionization mass spectrometry(HRESI-MS),and electronic circular dichroism(ECD)*** addition to structural determination,surface plasmon resonance(SPR)assays were conducted to investigate molecular interactions,revealing that compound 8 exhibited high affinity for vascular endothelial growth factor receptor 2(VEGFR2),a key regulator of tumor *** in vivo experiments demonstrated that compound 8 effectively inhibited angiogenesis and displayed significant antitumor activity by suppressing tumor proliferation and metastasis in zebrafish xenograft *** findings suggest that compound 8 holds promise as an anticancer lead compound targeting VEGFR-2 to obstruct tumor angiogenesis.

关键词： Clerodane diterpenoids Casearia graveolens Surface plasmon resonance Vascular endothelial growth factor receptor 2 Antitumor activity Zebrafish

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Effect of 5'-deletion of Arabi-dopsis profilin2 promoter on its vascular specific expression

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Chinese Science Bulletin 2001年第19期46卷 1627-1630页

作者： liu yuhui, WANG Zhixing & JIA ShirongBiotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China Biotechnology Research Institute Chinese Academy of Agricultural Sciences Beijing China

Based on the published sequence of profilin2 promoter of Arabidopsis thaliana, a full-length promoter (1667 bp) was amplified by PCR. The 5’ -end deletion fragments with length of 1380, 1153, 969 and 597 bp were then fused with gus (uid\) gene respectively. Constructed plant expression vectors were individually transferred into Kalan-choe laciniata and transgenic plants regenerated. GUS his-tochemical assay confirmed that the full-length promoter Pfnl.7 was vascular-specific. Deletion assays showed that profilin2 promoter could be divided into three parts. Deletion of fragment 1 ( -1667 -1380 bp) resulted in constitutive expression, suggesting that element(s) responsible for vascular-specific expression might exist in this region. Fragment 2 located at -1153 - -597 bp strongly inhibited gus gene expression. Fragment 3 ( -597 - -1 bp) is considered as a basic domain of profilin2.

关键词： profilin2 promoter Kalanchoe constitutive expression vascular-specific expression.

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Two-step calculation method to enable the ecological and human health risk assessment of remediated soil treated through thermal curing

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Soil Ecology Letters 2021年第3期3卷 266-278页

作者： Shaowen Xie Fei Wu Zengping Ning Manjia Chen Chengshuai liu Qiang Huang Fangyuan Meng yuhui liu Jimei Zhou Yafei Xia School of Environmental and Chemical Engineering Foshan UniversityFoshan 528000China National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China University of Chinese Academy of Sciences Beijing 100049China School of Food Science and Engineering Foshan UniversityFoshan 528000China

The centralized utilization of heavy-metal-contaminated soil has become the main strategy to remediate brownfield-site ***,few studies have evaluated the ecological and human health risks of reusing these remediated *** Zn as the target metal,systematic pHdependent leaching and the Community Bureau of Reference(BCR)extraction were conducted at six pH values(pH=2,4,6,8,10,12)for the remediated soil treated through thermal *** pHdependent leaching results showed that with the formation of ZnCr2O4 spinel phases,the remediated soil exhibited strong inherent resistance to acidic attack over longer leaching ***,the BCR extraction results showed that the leaching agent pH value mainly affected the acid-soluble fraction ***,a strong complementary relationship was noted between the leaching and acid-soluble fraction contents,indicating that the sum of these two parameters is representative of the remediated soil risk ***,we proposed a two-step calculation method to determine the sum of the two heavy metal parameters as the risk value of remediated *** contrast to the traditional one-step calculation method,which only uses the leaching content as the risk value,this two-step calculation method can effectively avoid underestimating the risk of remediated soil.

关键词： Remediated soil Heavy metal Leaching agent pH value Fraction distribution Ecological and human health risk

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Cadmium isotope compositions of Fe-Mn nodules and surrounding soils: Implications for tracing Cd sources

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Fundamental Research 2021年第3期1卷 269-276页

作者： Ting Gao yuhui liu Yafei Xia Jian-Ming Zhu Zhengrong Wang Meng Qi Yizhang liu Zengping Ning Qiqi Wu Wenpo Xu Chengshuai liu State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesBeijing 100083China Department of Earth&Atmospheric Sciences City College of New YorkCUNYNew York 10031United States National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China CAS Center for Excellence in Quaternary Science and Global Change Xi'an 710061China

Cadmium (Cd) pollution in agricultural soils has become a severe threat to food security and human health in recent years. Stable Cd isotopes are a potentially powerful tool for identifying the sources of Cd in soils. However, many Earth surface processes, including adsorption, leaching, and biogeochemical cycles in plants, may generate Cd isotope fractionation, which can complicate the potential application of Cd isotopes in tracing the sources of Cd pollution in soils. In this work, the Cd isotope compositions of typical Fe-Mn nodules (FMNs) and surrounding soils in two different soil profiles are investigated. Our results show that the FMNs in lower layers (i.e., C and W horizons) are isotopically lighter than the surrounding soils by –0.114‰ to –0.156‰ (Δ114/110CdFMN-soil). We interpret this fractionation as the result of preferential adsorption of isotopically light Cd onto the surface of goethite. In the upper layers (i.e., P and A horizons), the Δ114/110CdFMN-soil values are more negative in the P horizon (–0.213‰ to –0.388‰) but more positive in the A horizon (0.061‰ to 0.204‰). We interpret these fractionations as the result of natural biogeochemical processes (i.e., leaching and biological cycling) during soil development. Soil leaching preferentially releases isotopically heavy Cd into the underlying soil (i.e., P horizon), shifting the topsoil towards lower δ114/110Cd values but the underlying soils towards higher δ114/110Cd values. Moreover, biological cycling contributes isotopically heavy Cd to the topsoil, probably shifting the topsoil towards higher δ114/110Cd values. Our study demonstrates that the formation of Fe oxyhydroxides, leaching, and biological cycling can considerably modify the soil Cd isotope signature, highlighting the need to consider natural biogeochemical processes when using Cd isotopes to trace heavy metal pollution in soils.

关键词： Cadmium isotopes Fe-Mn nodules Leaching Biological cycling

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