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Research on the influence of flexible wheelset rotation effect on wheel rail contact force

Railway Sciences 2024年第3期3卷 367-387页

作者： Lixia Sun Yuanwu Cai di cheng Xiaoyi Hu Chunyang Zhou Railway Science and Technology Research and Development Center China Academy of Railway Sciences Corporation LimitedBeijingChina

Purpose-Under the high-speed operating conditions,the effects of wheelset elastic deformation on the wheel rail dynamic forces will become more notable compared to the low-speed condition.In order to meet different analysis requirements and selecting appropriate models to analyzing the wheel rail interaction,it is crucial to understand the influence of wheelset flexibility on the wheel-rail dynamics under different speeds and track excitations condition.Design/methodology/approach-The wheel rail contact points solving method and vehicle dynamics equations considering wheelset flexibility in the trajectory body coordinate system were investigated in this paper.As for the wheel-rail contact forces,which is a particular force element in vehicle multibody system,a method for calculating the Jacobian matrix of the wheel-rail contact force is proposed to better couple the wheel-rail contact force calculation with the vehicle dynamics response calculation.Based on the flexible wheelset modeling approach in this paper,two vehicle dynamic models considering the wheelset as both elastic and rigid bodies are established,two kinds of track excitations,namely normal measured track irregularities and short-wave irregularities are used,wheel-rail geometric contact characteristic and wheel-rail contact forces in both time and frequency domains are compared with the two models in order to study the influence of flexible wheelset rotation effect on wheel rail contact force.Findings-Under normal track irregularity excitations,the amplitudes of vertical,longitudinal and lateral forces computed by the flexible wheelset model are smaller than those of the rigid wheelset model,and the virtual penetration and equivalent contact patch are also slightly smaller.For the flexible wheelset model,the wheel rail longitudinal and lateral creepages will also decrease.The higher the vehicle speed,the larger the differences in wheel-rail forces computed by the flexible and rigid wheelset model.Under track short-wave irregularity excitations,the ve

关键词： Flexible wheelset Contact points calculation Rotational effects Elastic modes Wheel-rail force Papertype Researchpaper

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Research on the evolution law of dynamic performance of CR400BF EMU train based on stochastic dynamics simulation

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Railway Sciences 2024年第2期3卷 143-155页

作者： di cheng Yuqing Wen Zhiqiang Guo Xiaoyi Hu Pengsong Wang Zhikun Song Railway Science and Technology Research and Development Center China Academy of Railway Sciences Corporation LimitedBeijingChina School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijingChina

Purpose–This paper aims to obtain the evolution law of dynamic performance of CR400BF electric multiple unit(EMU).Design/methodology/approach–Using the dynamic simulation based on field test,stiffness of rotary arm nodes and damping coefficient of anti-hunting dampers were tested.Stiffness,damping coefficient,friction coefficient,track gauge were taken as random variables,the stochastic dynamics simulation method was constructed and applied to research the evolution law with running mileage of dynamic index of CR400BF EMU.Findings–The results showed that stiffness and damping coefficient subjected to normal distribution,the mean and variance were computed and the evolution law of stiffness and damping coefficient with running mileage was obtained.Originality/value–Firstly,based on the field test we found that stiffness of rotary arm nodes and damping coefficient of anti-hunting dampers subjected to normal distribution,and the evolution law of stiffness and damping coefficient with running mileage was proposed.Secondly stiffness,damping coefficient,friction coefficient,track gauge were taken as random variables,the stochastic dynamics simulation method was constructed and applied to the research to the evolution law with running mileage of dynamic index of CR400BF EMU.

关键词： Vehicle system dynamics Stiffness of rotary arm nodes Anti-snaking damper damping Random variable

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Toughening additive manufactured Zr-based bulk metallic glass composites by martensite phase transformation

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Journal of Materials Science & Technology 2024年第3期170卷 95-102页

作者： Pengcheng Zhang cheng Zhang Jie Pan di Ouyang Lin Liu State Key Laboratory of Materials Processing and die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

Additive manufacturing technology based on laser powder bed fusion(LPBF)offers a novel approach for fabricating bulk metallic glass(BMG)products without restriction in size and geometry.Nevertheless,the BMGs prepared by LPBF usually suffered from less plasticity and poorer fracture toughness as compared to their cast counterparts due to partial crystallization in heat-affected zones(HAZs).Since crystallization in HAZs is hard to avoid completely in LPBF BMGs,it is desirable to design a suitable alloy system,in which only ductile crystalline phase,instead of brittle intermetallics,is formed in HAZs.This unique structure could effectively increase the toughness/plasticity of the LPBF BMGs.To achieve this goal,a quaternary BMG system with a composition of Zr_(47.5)Cu_(45.5)Al_(5)Co_(2)is adopted and subjected to LPBF.It is found that nearly a single phase of B_(2)-ZrCu is precipitated in HAZs,while a fully amorphous phase is formed in molten pools(MPs).This B_(2)phase reinforced BMG composite exhibits excellent mechanical properties with enhanced plasticity and toughness.Furthermore,it is easy to modulate the mechanical properties by altering the amount of the B_(2)phase via adjusting the laser energy input.Finally,the best combination of strength,plasticity,and notch toughness is obtained in the BMG composite containing 27.4%B_(2)phase and 72.6%amorphous phase,which exhibits yield strength(σ_(s))of 1423 MPa,plastic strain(ε_(p))of 4.65%,and notch toughness(K_(q))of 53.9 MPa m 1/2.Furthermore,a notable strain-hardening is also observed.The improvement of plasticity/toughness and appearance of strain-hardening behavior are mainly due to the martensite phase transformation from the B_(2)phase to the Cm phase during plastic deformation(i.e.,the phase transformation-induced plasticity effect).The current work provides a guide for making advanced BMGs and BMG composites by additive manufacturing.

关键词： Laser powder bed fusion Bulk metallic glass composites Phase transformation-induced plasticity Deformation mechanism

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Cryptic diversity and rampant hybridization in annual gentians on the Qinghai-Tibet Plateau revealed by population genomic analysis

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Plant diversity 2024年第2期46卷 194-205页

作者： Peng-cheng Fu Qiao-Qiao Guo di Chang Qing-Bo Gao Shan-Shan Sun School of Life Science Luoyang Normal UniversityLuoyang 471934PR China Key Laboratory of Adaptation and Evolution of Plateau Biota Northwest Institute of Plateau BiologyChinese Academy of SciencesXining 810001PR China

Understanding the evolutionary and ecological processes involved in population differentiation and speciation provides critical insights into biodiversity formation. In this study, we employed 29,865 single nucleotide polymorphisms(SNPs) and complete plastomes to examine genomic divergence and hybridization in Gentiana aristata, which is endemic to the Qinghai-Tibet Plateau(QTP) region. Genetic clustering revealed that G. aristata is characterized by geographic genetic structures with five clusters(West, East, Central, South and North). The West cluster has a specific morphological character(i.e., blue corolla) and higher values of FSTcompared to the remaining clusters, likely the result of the geological barrier formed by the Yangtze River. The West cluster diverged from the other clusters in the Early Pliocene;these remaining clusters diverged from one another in the Early Quaternary. Phylogenetic reconstructions based on SNPs and plastid data revealed substantial cyto-nuclear conflicts. Genetic clustering and D-statistics demonstrated rampant hybridization between the Central and North clusters,along the Bayankala Mountains, which form the geological barrier between the Central and North clusters. Species distribution modeling demonstrated the range of G. aristata expanded since the Last Interglacial period. Our findings provide genetic and morphological evidence of cryptic diversity in G. aristata, and identified rampant hybridization between genetic clusters along a geological barrier.These findings suggest that geological barriers and climatic fluctuations have an important role in triggering diversification as well as hybridization, indicating that cryptic diversity and hybridization are essential factors in biodiversity formation within the QTP region.

关键词： Gentiana aristata Hybrid zone Qinghai-Tibet Plateau Plastome Nuclear SNPs

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Chemokine platelet factor 4 accelerates peripheral nerve regeneration by regulating Schwann cell activation and axon elongation

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Neural Regeneration Research 2024年第1期19卷 190-195页

作者： Miao Gu Xiao cheng di Zhang Weiyan Wu Yi Cao Jianghong He Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education Co-innovation Center of NeuroregenerationNMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology ProductsNantong UniversityNantongJiangsu ProvinceChina School of Basic Medical Sciences Hebei Key Laboratory of Nerve Injury and RepairChengde Medical UniversityChengdeHebei ProvinceChina

Schwann cells in peripheral nerves react to traumatic nerve injury by attempting to grow and regenerate.Howeve r,it is unclear what factors play a role in this process.In this study,we searched a GEO database and found that expression of platelet factor 4 was markedly up-regulated after sciatic nerve injury.Platelet factor is an important molecule in cell apoptosis,diffe rentiation,survival,and proliferation.Further,polymerase chain reaction and immunohistochemical staining confirmed the change in platelet factor 4 in the sciatic nerve at different time points after injury.Enzyme-linked immunosorbent assay confirmed that platelet factor 4 was secreted by Schwann cells.We also found that silencing platelet factor 4 decreased the proliferation and migration of primary cultured Schwann cells,while exogenously applied platelet factor 4 stimulated Schwann cell prolife ration and migration and neuronal axon growth.Furthermore,knocking out platelet factor 4 inhibited the prolife ration of Schwann cells in injured rat sciatic nerve.These findings suggest that Schwann cell-secreted platelet factor 4 may facilitate peripheral nerve repair and regeneration by regulating Schwann cell activation and axon growth.Thus,platelet factor 4 may be a potential therapeutic target for traumatic peripheral nerve injury.

关键词： axon elongation bioinformatic analysis cell migration cell proliferation dorsal root ganglia peripheral nerve regeneration peripheral nerve trauma platelet factor 4 rat sciatic nerve Schwann cells

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Streamflow abrupt change and the driving factors in glacierized basins of Tarim Basin,Northwest China

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Advances in Climate Change Research 2024年第1期15卷 75-89页

作者： cheng-De YANG Min XU Shi-Chang KANG Cong-Sheng FU Wei ZHANG di-di HU State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Watershed Geographic Sciences Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210000China

A climate transition towards warm-wet conditions in Northwest China has drawn much attention.With continuous climate change and universal glacier degradation,increasing water-related hazards and vulnerability have become one of the important problems facing the Tarim Basin.However,the impacts of the climate transition on streamflow abrupt change and extreme hydrological events were less discussed,especially in glacial basins.In the present study,the discharge datasets in four glacial basins of Tarim Basin from 1979 to 2018 were constructed using the GRU-GSWAT+model first.The differences in streamflow characteristics,the shift of hydrological extreme pattern,and potential changes of the controlling factors before and after the abrupt changes were investigated.The results indicated that the abrupt change point(ACP)in streamflow occurred in 2000 in the Qarqan River Basin,2002 in the Weigan River Basin,and 1994 in the Aksu River Basin and the Yarkant River Basin.A general decrease in streamflow before the ACP has shifted to a notable upward trend in the Qarqan River Basin and the Aksu River Basin,while minor upward fluctuations were observed in other basins.Moreover,the hydrological characteristics in extreme events vary dramatically before and after the ACPs,characterized by a pronouncing shift from drought-dominant pattern to wet events dominated pattern.The driven climate factors have been altered after the ACPs with notable spatial heterogeneity,in which temperature remained as the dominant role in meltwater-dominated basins while the influence of precipitation has increased after the ACPs,whereas the sensitivity of temperature on streamflow change has been enhanced in basins dominated by precipitation such as the Qarqan River Basin.Owing to the evident warming-wetting trend and glacier compensation effect,both the inter-annual and intra-annual streamflow fluctuations can be efficiently smoothed in basins with a high glacier area ratio(GAR).These findings provide a further understanding of the abrupt change in st

关键词： Abrupt change Streamflow Hybrid model Tarim Basin Glacier

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Prognostic value of a nomogram model for postoperative liver metastasis of colon cancer

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World Journal of Gastrointestinal Surgery 2024年第4期16卷 1055-1065页

作者： De-Xin cheng Kang-di Xu Han-Bo Liu Yi Liu Department of Interventional Medicine Zhejiang Provincial People’s Hospital(Affiliated People’s HospitalHangzhou Medical College)Hangzhou 310014Zhejiang ProvinceChina General Surgery Cancer CenterDepartment of Vascular SurgeryZhejiang Provincial People’s Hospital(Affiliated People’s HospitalHangzhou Medical College)Hangzhou 310014Zhejiang ProvinceChina

BACKGROUND Colon cancer is one of the most common malignant tumors of the digestive system.Liver metastasis after colon cancer surgery is the primary cause of death in patients with colon cancer.AIM To construct a novel nomogram model including various factors to predict liver metastasis after colon cancer surgery.METHODS We retrospectively analyzed 242 patients with colon cancer who were admitted and underwent radical resection for colon cancer in Zhejiang Provincial People’s Hospital from December 2019 to December 2022.Patients were divided into liver metastasis and non-liver metastasis groups.Sex,age,and other general and clinicopathological data(preoperative blood routine and biochemical test indexes)were compared.The risk factors for liver metastasis were analyzed using singlefactor and multifactorial logistic regression.A predictive model was then constructed and evaluated for efficacy.RESULTS Systemic inflammatory index(SII),C-reactive protein/albumin ratio(CAR),red blood cell distribution width(RDW),alanine aminotransferase,preoperative carcinoembryonic antigen level,and lymphatic metastasis were different between groups(Pdiagram prediction model constructed based on these risk factors to distinguish whether liver metastasis occurred postoperatively.The actual curve of the column-line diagram predicting the risk of postoperative liver metastasis was close to the ideal curve,with good agreement.The prediction model curves in the decision curve analysis showed higher net benefits for a larger threshold range than those in extreme cases,indicating that the model is safer.CONCLUSION Liver metastases after colorectal cancer surgery could be well predicted by a nomogram based on the SII,CAR,and RDW.

关键词： Systemic immunoinflammatory index C-reactive protein/albumin ratio Erythrocyte distribution width Colon cancer Liver metastasis Novel nomogram model

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Optical two-dimensional coherent spectroscopy of excitons in transition-metal dichalcogenides

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Frontiers of physics 2024年第2期19卷 141-148页

作者： YanZuo Chen ShaoGang Yu Tao Jiang XiaoJun Liu XinBin cheng di Huang State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsInnovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430071China MOE Key Laboratory of Advanced Micro-Structured Materials Shanghai Frontiers Science Center of Digital OpticsInstitute of Precision Optical Engineeringand School of Physics Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Intelligent Science and Technology Tongji UniversityShanghai 200092China

Exciton physics in atomically thin transition-metal dichalcogenides(TMDCs)holds paramount importance for fundamental physics research and prospective applications.However,the experimental exploration of exciton physics,including excitonic coherence dynamics,exciton many-body interactions,and their optical properties,faces challenges stemming from factors such as spatial heterogeneity and intricate many-body effects.In this perspective,we elaborate upon how optical two-dimensional coherent spectroscopy(2DCS)emerges as an effective tool to tackle the challenges,and outline potential directions for gaining deeper insights into exciton physics in forthcoming experiments with the advancements in 2DCS techniques and new materials.

关键词： monolayer transition-metal dichalcogenides two-dimensional coherent spectroscopy

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A naturally derived small molecule compound suppresses tumor growth and metastasis in mice by relieving p53-dependent repression of CDK2/Rb signaling and the Snail-driven EMT

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Chinese Journal of Natural Medicines 2024年第2期22卷 112-126页

作者： REN Boxue LI Yang di Lei cheng Ranran LIU Lijuan LI Hongmei LI Yi TANG Zhangrui YAN Yongming LU Tao FU Rong cheng Yongxian WU Zhaoqiu State Key Laboratory of Natural Medicines Department of PharmacologySchool of PharmacyChina Pharmaceutical UniversityNanjing 211198China Institute for Inheritance-Based Innovation of Chinese Medicine School of Pharmaceutical SciencesShenzhen University Health Science CenterShenzhen 518060China

The tumor suppressor protein p53 is central to cancer biology,with its pathway reactivation emerging as a promising therapeutic strategy in oncology.This study introduced LZ22,a novel compound that selectively inhibits the growth,migration,and metastasis of tumor cells expressing wild-type p53,demonstrating ineffectiveness in cells devoid of p53 or those expressing mutant p53.LZ22’s mechanism of action involves a high-affinity interaction with the histidine-96 pocket of the MDM2 protein.This interaction disrupted the MDM2-p53 binding,consequently stabilizing p53 by shielding it from proteasomal degradation.LZ22 impeded cell cycle progression and diminished cell proliferation by reinstating the p53-dependent suppression of the CDK2/Rb signaling pathway.Moreover,LZ22 alleviated the p53-dependent repression of Snail transcription factor expression and its consequent EMT,effectively reducing tumor cell migration and distal metastasis.Importantly,LZ22 administration in tumor-bearing mice did not manifest notable side effects.The findings position LZ22 as a structurally unique reactivator of p53,offering therapeutic promise for the management of human cancers with wild-type TP53.

关键词： LZ22 Wild-type p53 p53 Reactivator Snail-driven EMT Tumor growth and metastasis

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Polymorphic cerium-based Prussian blue derivatives with in situ growing CNT/Co heterojunctions for enhanced microwave absorption via polarization and magnetization

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Nano Research 2024年第3期17卷 2050-2060页

作者： Jixi Zhou Xinmeng Huang di Lan Yuhang cheng Fengyi Xue Chenyu Jia Guanglei Wu Zirui Jia Institute of Materials for Energy and Environment State Key Laboratory of Bio-fibers and Eco-textilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071China School of Materials Science and Engineering Hubei University of Automotive TechnologyShiyan 442002China College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071China

In this paper,the structure evolution of cerium cobaltohexanoate(Ce[Co(CN)6],Ce-Co Prussian blue analog(PBA))has been realized by solvent catalysis at room temperature.The hexagonal bipyramidal microcrystals of Ce-Co PBA can be gradually transformed into dendrites by different proportions of ethanol(EtOH)and water.At the same time,the porous dendrites CeO_(2)/Co@carbon nanotub(CNT)with oxygen-rich vacancies(OVs)can be obtained by annealing Ce-Co PBA at 700℃.The microstructure study shows that carbon nanotubes will be catalyzed after annealing at high temperature,and the cobalt metal particles encapsulated in carbon nanotubes will be anchored in the matrix,regulating the impedance matching and multi-polarization suppression of the material,and its unique structure,vacancies,and strong interface effect make the material exhibit excellent electromagnetic wave(EMW)absorption performance.When the matching thickness is 2.5 mm,the minimum reflection loss(RLmin)of the composite is-51.68 dB,and the effective absorption bandwidth(RLdidate material for EMW absorption.

关键词： Ce-Co Prussian blue analog(PBA) carbon nanotubes(CNTs) CeO_(2)/Co@CNT solvent catalysis electromagnetic wave absorption

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