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Cerium refinement of grains and primary carbides during solidification of Cr_(4)Mo_(4)V bearing steel

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Journal of Rare Earths 2024年第4期42卷 783-792页

作者： Weifeng Liu jianqiang wang Mingyue Sun Bin Xu Jiahao Yao Qunbo Fan Dianzhong Li Chongqing Innovation Center Beijing Institute of TechnologyChongqing401135China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

The effect of cerium(Ce)on the solidification microstructure of Cr_(4)Mo_(4)V bearing steel was investigated via a combined experimental and theoretical method.With a trace amount(0.056 wt%)of Ce addition,the coarse columnar grains in as-cast microstructure transform into equiaxed ones,and the average diameter is reduced from 56 to 27μm.The network-like and bulky primary MC and M2C carbides at the interdendritic regions become disconnected and refined,and their volume percentage decreases from4.15 vol%to 2.1 vol%.Ce-inclusions acting as heterogeneous nucleation agents of prior-austenite grains and Ce atoms segregating at grain boundaries,both contribute to the refinement of grains.Thermodynamic calculations reveal that primary carbides are precipitated afterγ-austenite forms near the end of the solidification process.The modification of primary carbides in size and amount is mainly attributed to the isolated remaining melt separated by refinedγ-austenite grains in which the nucleation of carbides is promoted,while the growth is restrained owing to the less segregation of alloying elements.

关键词： Cr_(4)Mo_(4)V bearing steel Rare Earths Grains Primary carbides Refinement

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Metal size effects over metal/zeolite bifunctional catalysts in the selective hydroalkylation of benzene

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Frontiers of Chemical Science and Engineering 2024年第4期18卷 107-114页

作者： Junjie Li Chuang Liu Zhenlong Jia Yingchun Ye Dawei Lan Wei Meng jianqiang wang Zhendong wang Yongfeng Hu Weimin Yang State Key Laboratory of Green Chemical Engineering and Industrial Catalysis Sinopec Shanghai Research Institute of Petrochemical Technology Co.Ltd.Shanghai 201208China School of Chemical Engineering East China University of Science and TechnologyShanghai 200237China

Bifunctional metal/zeolite materials are some of the most suitable catalysts for the direct hydroalkylation of benzene to cyclohexylbenzene.The overall catalytic performance of this reaction is strongly influenced by the hydrogenation,which is dependent on the metal sizes.Thus,systematically investigating the metal size effects in the hydroalkylation of benzene is essential.In this work,we successfully synthesized Ru and Pd nanoparticles on Sinopec Composition Materials No.1 zeolite with various metal sizes.We demonstrated the size-dependent catalytic activity of zeolite-supported Ru and Pd catalysts in the hydroalkylation of benzene,which can be attributed to the size-induced hydrogen spillover capability differences.Our work presents new insights into the hydroalkylation reaction and may open up a new avenue for the smart design of advanced metal/zeolite bi-functional catalysts.

关键词： size effects bifunctional catalysts metal/zeolite hydroalkylation

General Optimal Trajectory Planning:Enabling Autonomous Vehicles with the Principle of Least Action

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Engineering 2024年第2期33卷 63-76页

作者： Heye Huang Yicong Liu Jinxin Liu Qisong Yang jianqiang wang David Abbink Arkady Zgonnikov School of Vehicle and Mobility Tsinghua UniversityBeijing 100084China Department of Cognitive Robotics Faculty of MechanicalMaritime and Materials Engineering(3mE)Delft University of TechnologyDelft 2628Netherlands Department of Software Technology Faculty of Electrical EngineeringMathematics and Computer ScienceDelft University of TechnologyDelft 2628Netherlands Xi’an Institute of High-Technology Xi’an 710051China

This study presents a general optimal trajectory planning(GOTP)framework for autonomous vehicles(AVs)that can effectively avoid obstacles and guide AVs to complete driving tasks safely and efficiently.Firstly,we employ the fifth-order Bezier curve to generate and smooth the reference path along the road centerline.Cartesian coordinates are then transformed to achieve the curvature continuity of the generated curve.Considering the road constraints and vehicle dynamics,limited polynomial candidate trajectories are generated and smoothed in a curvilinear coordinate system.Furthermore,in selecting the optimal trajectory,we develop a unified and auto-tune objective function based on the principle of least action by employing AVs to simulate drivers’behavior and summarizing their manipulation characteristics of“seeking benefits and avoiding losses.”Finally,by integrating the idea of receding-horizon optimization,the proposed framework is achieved by considering dynamic multi-performance objectives and selecting trajectories that satisfy feasibility,optimality,and adaptability.Extensive simulations and experiments are performed,and the results demonstrate the framework’s feasibility and effectiveness,which avoids both dynamic and static obstacles and applies to various scenarios with multi-source interactive traffic participants.Moreover,we prove that the proposed method can guarantee real-time planning and safety requirements compared to drivers’manipulation.

关键词： Autonomous vehicle Trajectory planning Multi-performance objectives Principle of least action

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Rice Bran-derived Peptide KF-8 Attenuates Dexamethasone-induced Myopathy in Caenorhabditis elegans by Regulating Locomotion-related Genes

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Food Science and Human Wellness 2024年

作者： Yixin Wu jianqiang wang Fang Huang Yajuan Chen Qinlu Lin Zhongxu Chen Zhigang Liu Yao Jiang Wenqing Xie Hengzhen Li Yusheng Li Ying Liang National Clinical Research Center for Geriatric Disorders Xiangya Hospital Central South University Molecular Nutrition Branch National Engineering Research Center of Rice and By-product Deep Processing College of Food Science and Engineering Central South University of Forestry and Technology Laboratory of Functional Chemistry and Nutrition of Food College of Food Science and Engineering Northwest A&F University The Key Lab of Non-wood Forest Cultivation and Protection of Education Ministry The Key Lab of Non-wood Forest Products of Forestry Ministry Forestry Institute Central South University of Forestry & Technology Department of Orthopedics Xiangya Hospital Central South University

Background and aims: Dexamethasone is a common glucocorticoid medication with adverse effects that can cause muscle atrophy， but no drug intervention has been approved or recommended for this condition. KF-8 is a rice bran-derived anti-oxidant peptide that extends the life span of Caenorhabditis elegans. Methods: We established a C. elegans model of dexamethasone-induced myopathy to evaluate the potential therapeutic effects of KF-8 in this model. C. elegans muscle function was assessed in terms of locomotory behaviors including crawling， swimming， burrowing， pharyngeal pumping， and head swing. Muscle actin filament integrity was evaluated using fluorescence imaging. The molecular mechanisms of KF-8 were investigated using transcriptome sequencing， qRT-PCR， RNA interference， and western blot analysis. Results: Dexamethasone disrupted actin filaments in the striated muscles of the body wall and inhibited C. elegans crawling， swimming， burrowing， pharyngeal pumping， and head swing. KF-8 reversed the actin filament disruption and locomotor dysfunction induced by dexamethasone. Transcriptome sequencing， pathway enrichment， and qRT-PCR analyses revealed that KF-8 regulated the locomotion-related genes W04G5.10， vha-12， and ddr-1， as well as age-1 (the catalytic subunit ortholog of PI3K)， and akt1. RNA interference， conducted using a genetically engineered E. coli HT115 strain as a food source， confirmed age-1 as a key regulator of locomotor function of C. elegans. Further mechanistic studies with C2C12 myotubes showed that KF-8 regulated the IRS-PI3K-Akt pathway， the master regulator of protein synthesis and degradation. Conclusion: Together， these findings suggest that KF-8 protects against dexamethasone-induced myopathy in C. elegans by regulating locomotion-related genes and the IRS-PI3K-Akt pathway.

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Energy dissipation mechanism and ballistic characteristic optimization in foam sandwich panels against spherical projectile impact

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Defence Technology（防务技术） 2024年第5期35卷 108-122页

作者： jianqiang Deng Tao Liu Liming Chen Xin Pan Jingzhe wang Shaowei Zhu Weiguo Li College of Aerospace Engineering Chongqing UniversityChongqing 400030China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400030China Chongqing Key Laboratory of Heterogeneous Material Mechanics Chongqing UniversityChongqing 400030China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

This study systematically examines the energy dissipation mechanisms and ballistic characteristics of foam sandwich panels(FSP)under high-velocity impact using the explicit non-linear finite element method.Based on the geometric topology of the FSP system,three FSP configurations with the same areal density are derived,namely multi-layer,gradient core and asymmetric face sheet,and three key structural parameters are identified:core thickness(t_(c)),face sheet thickness(t_(f))and overlap face/core number(n_(o)).The ballistic performance of the FSP system is comprehensively evaluated in terms of the ballistic limit velocity(BLV),deformation modes,energy dissipation mechanism,and specific penetration energy(SPE).The results show that the FSP system exhibits a significant configuration dependence,whose ballistic performance ranking is:asymmetric face sheet>gradient core>multi-layer.The mass distribution of the top and bottom face sheets plays a critical role in the ballistic resistance of the FSP system.Both BLV and SPE increase with tf,while the raising tcor noleads to an increase in BLV but a decrease in SPE.Further,a face-core synchronous enhancement mechanism is discovered by the energy dissipation analysis,based on which the ballistic optimization procedure is also conducted and a design chart is established.This study shed light on the anti-penetration mechanism of the FSP system and might provide a theoretical basis for its engineering application.

关键词： Sandwich panel Numerical simulation Ballistic resistance Specific penetration energy Energy analysis

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A method to predict rockburst using temporal trend test and its application

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 909-923页

作者： Yarong Xue Zhenlei Li Dazhao Song Xueqiu He Honglei wang Chao Zhou jianqiang Chen Aleksei Sobolev School of Civil and Resources Engineering University of Science and Technology BeijingBeijing100083China Zhong-an Academy of Safety Engineering Beijing100083China China Energy Group Xinjiang Energy Co. LtdUrumqi830027China Khabarovsk Federal Research Center of the Far Eastern Branch of the Russian Academy of Sciences(KhFRC FEB RAS) 51 Turgenev StreetKhabarovsk680000Russia

Rockbursts have become a significant hazard in underground mining,underscoring the need for a robust early warning model to ensure safety management.This study presents a novel approach for rockburst prediction,integrating the Mann-Kendall trend test(MKT)and multi-indices fusion to enable real-time and quantitative assessment of rockburst hazards.The methodology employed in this study involves the development of a comprehensive precursory index library for rockbursts.The MKT is then applied to analyze the real-time trend of each index,with adherence to rockburst characterization laws serving as the warning criterion.By employing a confusion matrix,the warning effectiveness of each index is assessed,enabling index preference determination.Ultimately,the integrated rockburst hazard index Q is derived through data fusion.The results demonstrate that the proposed model achieves a warning effectiveness of 0.563 for Q,surpassing the performance of any individual index.Moreover,the model’s adaptability and scalability are enhanced through periodic updates driven by actual field monitoring data,making it suitable for complex underground working environments.By providing an efficient and accurate basis for decision-making,the proposed model holds great potential for the prevention and control of rockbursts.It offers a valuable tool for enhancing safety measures in underground mining operations.

关键词： Rockburst Microseismicity Early warning Mann-Kendall trend test Confusion matrix Multi-indices fusion

A Cross-Sectional Survey of Iodized Salt Usage in Dining Establishments—13 PLADs,China,2021–2022

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China CDC weekly 2023年第34期5卷 751-755页

作者： Ying Zhang Jichun wang Xiuwei Li Wei Ma jianqiang wang Haiyan wang Jing Xu National Health Commission Key Laboratory of Trace Element Nutrition National Institute for Nutrition and HealthChinese Center for Disease Control and PreventionBeijingChina Science and Technology Department Chinese Center for Disease Control and PreventionBeijingChina.

Summary What is already known about this topic?The National Iodine Deficiency Disease Surveillance system is exclusively focused on monitoring cooking salt used within households.Currently,there is a lack of nationally representative data on the use of iodized salt in dining establishments.What is added by this report?This study evaluated 7,889 salt samples obtained from dining establishments located in 13 provincial-level administrative divisions across China.The findings indicated that coverage rate of iodized salt(CRIS)and the consumption rate of adequately iodized salt(CRAIS)were found to be 95.2%and 90.2%,respectively.Further,880 samples were classified as iodized salt and 804 as adequately iodized salt.In coastal areas,the CRIS and CRAIS showed a significant decrease to 77.1%and 70.5%,respectively,when compared to the inland regions(P<0.01).

关键词： finding system inland

Influence of tungsten particle size on microstructure and mechanical properties of high strength and tough tungsten particle-reinforced nickel-based composites by laser-direct energy deposition

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Journal of Materials Science & Technology 2024年第5期172卷 213-227页

作者： Wenji Song Dengzhi wang Congwen Tang Pengfei Sun Jiaxing Yang Zhidong Xu Tao Lai jianqiang Gong Qianwu Hu Xiaoyan Zeng Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430000China

Tungsten(W)particle-reinforced nickel(Ni)-based composites were fabricated via laser-direct energy de-position(L-DED).The influence of the W particle size on the microstructure and mechanical properties of the deposited samples was systematically studied.The results indicate that refining the W particle size could refine theγ-Ni grains and subgrains,thin the(Ni,Cr)_(4)W interface layer,and increase the disloca-tion density of the intergranular matrix,thus improving the tensile strength and elongation of the L-DED samples.As W particle size decreased from 75 to 150μm to 6.5-12μm,the tensile strength and elonga-tion of the deposited samples increased by 150 MPa and 2.9 times to 1347.6±15.7 MPa and 17.5±0.4%,respectively.Based on the properties of the interface(Ni,Cr)_(4)W,a load-transfer efficiency factor suitable for this composite was proposed and the load-transfer strengthening formula was optimized.A quanti-tative analysis of the strengthening mechanisms was established considering load-transfer strengthening,Hall-Petch strengthening,thermal-mismatch strengthening,and solid-solution strengthening.The calcu-lated contribution of each strengthening mechanism to the yield strength and theoretical calculations were in good agreement with the experimental data.The article breaks the bottleneck of poor plasticity of W particle-reinforced Ni-based composites prepared by L-DED and provides a theoretical basis for the construction design of W particle-reinforced Ni-based composites with excellent mechanical properties.

关键词： Laser-direct energy deposition(L-DED) Tungsten particle reinforcements Mechanical property Strengthening mechanism

Actively Reconfigurable Valley Topological Edge and Corner States in Photonic Crystals Based on Phase Change Material Ge2Sb2Te5

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激光与光电子学进展 2024年第5期61卷 557-571页

作者： Li Wei Peng Yuxiang Su Peihao Li Jianbo wang Kaijun Liu Exian Liu jianqiang He Mengdong College of Science Hunan Province Key Laboratory of Materials Surface&Interface Science and TechnologyCentral South University of Forestry and TechnologyChangsha 410004HunanChina College of Science Jiujiang UniversityJiujiang 332005JiangxiChina

The immunity of topological states against backscattering and structural defects provides them with a unique advantage in the exploration and design of high-precision low-loss optical devices.However,the operating bandwidth of the topological states in certain photonic structures is difficult to actively tune and flexibly reconfigure.In this study,we propose a valley topological photonic crystal(TPC)comprising two inverse honeycomb photonic crystals,consisting of hexagonal silicon and Ge2Sb2Te5(GST)rods.When GST transitions from the amorphous phase to the crystalline phase,the edge band of the TPC appears as a significant redshift and is inversed from a“∪”to an“∩”shape with topological phase transition,which enables active tuning of the operating bandwidth and propagation direction of topological edge states.Both the topological edge and corner states in a triangular structure constructed using TPCs can be simultaneously adjusted and reconfigured via GST phase transition,along with a change in the group number of corner states.Using the adjustability of topological edge states and electromagnetic coupling between two different topological bearded interfaces,we develop a multichannel optical router with a high tuning degree of freedom,where channels can be actively reconfigured and their on/off states can be freely switched.Our study provides a strategy for the active regulation of topological states and may be beneficial for the development of reconfigurable topological optical devices.

关键词： topological edge states topological corner states phase change material active reconfiguration topological photonic crystal

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