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Effect of Extrusion Temperatures on Friction-wear Behavior of Chain-wheel Fabricated by 40Cr Steel under Oil-lubrication Condition

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Journal of Wuhan University of Technology(Materials Science) 2019年第3期34卷 684-691页

作者： CHEN Haixiang KONG dejun School of Mechanical Engineering Changzhou University

A 40 Cr steel was formed into a chain-wheel using a warm extrusion technology. The surface roughness and micro-structure, micro-hardness and phases of the extruded samples at different temperatures were analyzed using a three-dimensional optical microscope(OM), micro-hardness tester, and X-ray diffraction(XRD), respectively. The morphologies, chemical element distributions and phases of worn tracks at the extrusion temperatures of 550, 650 and 750 ℃ were analyzed using a scanning electron microscopy(SEM), energy disperse spectroscopy(EDS), and XRD, respectively. The friction-wear behaviors of extruded samples under oil-lubrication condition were observed using a wear test. And the effects of extrusion temperatures on the wear mechanism were discussed. The results show that residual austenite and pearlite exist on the sample at the extrusion temperature of 550 ℃ with the corresponding grain size and surface micro-hardness of 32.7 nm and 370.33 HV, respectively. The average coefficient of friction(COF) of extruded sample at the temperature of 550 ℃ is 0.196 5, and the wear mechanism is fatigue and abrasive wear. While the acicular martensite exists on the extruded samples at the extrusion temperatures of 650 and 750 ℃, the corresponding grain sizes are 30.0 and 29.1 nm, respectively. The average COF(coefficient of friction) of extruded sample at the temperatures of 650 and 750 ℃ are 0.187 4 and 0.163 6, respectively, and the wear mechanism is abrasive wear. As a result, the friction performance of extruded sample at the temperatures of 650 and 750 ℃ is better than that at the temperature of 550 ℃.

关键词： warm extrusion 40Cr steel extrusion temperature coefficient of friction (COF) wear mechanism

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小针刀神经根管直接松解术治疗根型颈椎病随机双盲对照临床研究

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中国医药科学 2013年第7期3卷 23-26,46页

作者：田和炳陆亮亮蒋晓明李兴勇吴蓉郭旗黄德军四川省德阳市旌阳区中医院康复科四川德阳618000

目的在前期探索基础上进一步研究小针刀神经根管直接松解术治疗根型颈椎病临床疗效及安全性。方法将50例根型颈椎病患者按随机双盲对照法分为治疗组及对照组各25例,两组均给予针灸、推拿、牵引及中药辨证施治内服治疗,治疗组加载小针刀... 详细信息

目的在前期探索基础上进一步研究小针刀神经根管直接松解术治疗根型颈椎病临床疗效及安全性。方法将50例根型颈椎病患者按随机双盲对照法分为治疗组及对照组各25例,两组均给予针灸、推拿、牵引及中药辨证施治内服治疗,治疗组加载小针刀神经根管直接松解术,对照组加载神经根管假松解术。以无效、疗效不佳而要求结束试验为观察终点,试验中进行症状体征积分及MPQ量表评定、不良事件调查并记录,并随访半年。结果治疗组疗效率明显优于对照组(P0.05),治疗组小针刀操作中2例出现神经根损伤,出现患肢麻木疼痛,未经特殊处理后分别于10、15d症状体征消失。结论小针刀神经根管直接松解术治疗神经根型颈椎病在总体疗效上有一定优势,但其不良反应较重,潜在风险较高,尚需进一步探索更安全有效的技术方案。

关键词：小针刀神经根管直接松解术神经根管间接松解术神经根型颈椎病

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Experimental and numerical study of coal-rock bimaterial composite bodies under triaxial compression

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International Journal of Coal Science & Technology 2021年第5期8卷 908-924页

作者： Yulong Chen Jianping Zuo dejun Liu Yingjie Li Zhenbo Wang State Key Laboratory of Coal Resources and Safe Mining China University of Mining and TechnologyBeijing 100083China School of Energy and Mining Engineering China University of Mining and TechnologyBeijing 100083China School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing 100083China

To accurately predict coal burst hazards and estimate the failure of coal pillars in underground coal mining systems,it is of great significance to understand the mechanical behavior of coal-rock bimaterial composite *** paper presents experimental and numerical investigations on the response of rock-coal,coal-rock,and rock-coal-rock bimaterial composite structures under triaxial *** triaxial compression experiments are conducted under confining pressures in the range of 0-20 *** resulting inside fracture networks are detected using X-ray-based computed tomography(CT).The experimentally observed data indicate that the mechanical parameters of the rock-coalrock composites are superior to those of the rock-coal and coal-rock *** compression failure,the coal-rock combination specimens are analyzed via X-ray *** results display that the failure of the coal-rock composite bodies primarily takes place within the ***,the bursting proneness is reduced by increasing confining ***,the corresponding numerical simulations of the experiments are carried out by using the particle flow *** numerical results reveal that coal is vulnerable with regard to energy storage and accumulation.

关键词： Coal-rock bimaterial composite body Triaxial compression Strength and deformation X-ray CT Numerical simulation Energy

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Catalytic Combustion of Lean Methane Assisted by Electric Field over Pd/Co_3O_4 Catalysts at Low Temperature

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Journal of Shanghai Jiaotong university(Science) 2018年第S1期23卷 8-17页

作者： LIU Ke LI Ke XU dejun LIN He GUAN Bin CHEN Ting huang Zhen Key Laboratory for Power Machinery and Engineering of Ministry of Education Shanghai Jiao Tong University

A series of Pd/Co_3O_4 catalysts were prepared by Self-Propagating High-Temperature Synthesis(SHS)method in this study, and electric field was applied for catalytic combustion of lean methane over Pd/Co_3O_4 catalysts at low temperature. When electric field was applied, the catalytic combustion performance of Pd/Co_3O_4 catalysts was greatly improved, and the application of electric field could reduce the load of active element Pd to some extent while maintaining the same efficiency. Based on experimental tests and the analysis results of X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), H2-temperature-programmed reduction(H2-TPR) and in-situ diffuse reflectance infrared Fourier transform spectroscopy(in-situ DRIFTS), the mechanism of catalytic oxidation of CH_4 over Pd/Co_3O_4 catalysts in electric field was proposed. The catalytic combustion of CH_4 occurs only when the temperature is higher than 250?C normally, but when electric field was applied, the whole process of CH_4 oxidation was promoted significantly and the reaction temperature was reduced. Electric field could promote the reduction of the support Co_3O_4 to release the lattice oxygen, resulting in the increase of PdOxand the surface chemisorbed oxygen, which could provide more active sites for the low-temperature oxidation of CH_4. Furthermore, electric field could accelerate the dehydroxylation of CoOOH to further enhance the activity of the catalysts.

关键词： electric field methane oxidation Pd/Co_3O_4 catalyst in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS) mechanism

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Assessing Drought Conditions in Cloudy Regions Using Reconstructed Land Surface Temperature

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Journal of Meteorological Research 2020年第2期34卷 264-279页

作者： Shiqi YANG dejun ZHANG Liang SUN Yongqian WANG Yanghua GAO Chongqing Institute of Meteorological Sciences Chongqing 401147 College of Resources and Environment Chengdu University of Information TechnologyChengdu 610225 Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences/Key Laboratory of Agricultural Remote SensingMinistry of Agriculture and Rural Affairs of the People’s Republic of ChinaBeijing 100081

Temperature vegetation dryness index(TVDI)in a triangular or trapezoidal feature space can be calculated from the land surface temperature(LST)and normalized difference vegetation index(NDVI),and has been widely applied to regional drought ***,thermal infrared sensors cannot penetrate clouds to detect surface information of sub-cloud *** cloudy areas,LST data include a large number of cloudy pixels,seriously degrading the spatial and temporal continuity of drought *** this paper,the Remotely Sensed Daily Land Surface Temperature Reconstruction model(RSDAST)is combined with the LST reconstructed(RLST)by the RSDAST and applied to drought monitoring in a cloudy *** drought monitoring capability of the reconstructed temperature vegetation drought index(RTVDI)under cloudy conditions is evaluated by comparing the correlation between land surface observations for soil moisture and the TVDI before and after surface temperature *** show that the effective duration and area of the RTVDI in the study area were larger than those of the original TVDI(OTVDI)in *** addition,RLST/NDVI scatter plots cover a wide range of values,with the fitted dry–wet boundaries more representative of real soil moisture *** continuously cloudy conditions,the OTVDI inverted from the original LST(OLST)loses its drought monitoring capability,whereas RTVDI can completely and accurately reconstruct surface moisture conditions across the entire study *** correlation between TVDI and soil moisture is stronger for RTVDI(R=-0.45)than that for OTVDI(R=-0.33).In terms of the spatial and temporal distributions,the R value for correlation between RTVDI and soil moisture was higher than that for ***,in continuously cloudy areas,RTVDI not only expands drought monitoring capability in time and space,but also improves the accuracy of surface soil moisture monitoring and enhances the applicability and reliability of thermal infrared

关键词： land surface temperature reconstruction Remotely Sensed Daily Land Surface Temperature Reconstruction model(RSDAST) temperature vegetation dryness index(TVDI) soil moisture drought

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Modern Composite Materials and Technical Strategies in Posttraumatic Augmentation Rhinoplasty

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Chinese Journal of Plastic and Reconstructive Surgery 2020年第1期2卷 59-62页

作者： Jiaman GAO dejun CAO Department of Plastic and Reconstructive Surgery Shanghai Ninth HospitalShanghai Jiao Tong University School of MedicineShanghai

The selection of ideal posttraumatic augmentation rhinoplasty materials and technical strategies has always been a pressing *** to the complexity of the traumatic nasal anatomical structure,such procedures are more complicated than ordinary cosmetic *** choice of reconstruction material should emphasize its inherent characteristics,such as biocompatibility,anti-infective ability,strength,and *** the development of rhinoplasty,the choice of material is less limited and composite materials have become *** review outlines current composite materials and techniques in posttraumatic augmentation rhinoplasty.

关键词： posttraumatic augmentation rhinoplasty composite materials osseous-cartilaginous rib grafts alloplastic implant acellular dermal matrix 3D-printed implants

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Research on mechanical performance of longitudinal joints in segmental tunnel linings strengthened by fiber-reinforced plastic grid with polymer−cement−mortar method

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Frontiers of Structural and Civil Engineering 2024年第10期18卷 1610-1625页

作者： Xianda FENG dejun LIU Yihao GUO Fei ZHONG Jianping ZUO Wei LIU School of Civil Engineering and Architecture University of JinanJinan 250022China School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing 100083China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and TechnologyBeijing 100083China

In this study,we propose the use of a fiber-reinforced plastic grid with polymer−cement−mortar(FRP Grid-PCM)to reinforce segment joints in tunnel shield *** joints play a crucial role in determining bearing capacity but are vulnerable to deterioration during *** investigate how to enhance the flexural performance of longitudinal shield lining joints,we built eccentric short column specimens by bolting two half-corbel columns together and tested them in the *** test program comprised two control specimens and three strengthened specimens with FRP grid applied on one side,away from the axial *** tests varied two main parameters:loading eccentricity and the number of FRP grid *** conducted a detailed analysis of the failure process,bearing capacity,and bending stiffness of longitudinal joints under different ***,we developed an analytical model to predict the flexural bearing capacity of longitudinal joints upgraded with the FRP Grid-PCM method and validated it through experimental *** research demonstrates that the FRP grid effectively reduces joint opening and rotation angles while enhancing the bearing capacity of the short column,particularly with concurrent increases in loading eccentricity and the number of FRP grid ***,our findings offer a novel alternative for improving the flexural performance of longitudinal joints in shield tunnels.

关键词： longitudinal joints flexural performance eccentric short column fiber-reinforced grid experiment theoretical model

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Spatially controlled lithium deposition on Li_(x)Cu_(y)P_(z) arrays enabling highly stable lithium metal batteries

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Journal of Materials Science & Technology 2023年第21期152卷 212-219页

作者： Ying Zhou Xiangru Sun Peiran Tan Yueming Wang Hongyang Dong dejun Li Tianjin International Joint Research Centre of Surface Technology for Energy Storage Materials College of Physics and Materials ScienceTianjin Normal UniversityTianjin 300387China

Lithium(Li)metal is a potential anode for high-energy-density batteries because of its low potential and ultrahigh ***,the Li dendrites formation,the ununiform Li deposition,and the growth of Li dendrites hamper its application,especially under high deposition capacity/high ***,a spatially controlled Li deposition mode with array-oriented morphology is achieved based on the novel mixed ion/electron-conducting Li_(x)Cu_(y)P_(z) arrays constructed on Cu foil,which can be facile fabricated via an in-situ transformation of metal *** calculations indicate the excellent lithiophilicity and low Li diffusion barrier of the arrays,especially for the Li_(2)CuP phase,which are conducive to ho-mogenizing the Li nucleation/deposition of ***,such mixed conducting arrays promote fast Li+diffusion via the continuous Li+pathways as well as modulate the Li+flux/electric ***,the arrays with enlarged specific surface area and open spaces reduce the local current density and alle-viate the volume fluctuation of ***,a dendrite-free Li anode is obtained under a high rate(20 mA cm^(–2))or a high deposition capacity(10 mAh cm^(–2)).In addition,even if the negative/positive ratio reduces to only 1.1,the full cells still perform outstanding stability for over 200 *** work empha-sizes the importance of the design of the framework in terms of the intrinsic properties and structure and reveals a pathway for developing Li metal batteries.

关键词： Li metal Li dendrites Metal phosphates Lithiophilic Mixed conductor Full cell

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SNP-based linkage mapping for validation of adult plant stripe rust resistance QTL in common wheat cultivar Chakwal 86

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The Crop Journal 2019年第2期7卷 176-186页

作者： Qingdong Zeng Jianhui Wu Shuo huang Fengping Yuan Shengjie Liu Qilin Wang Jingmei Mu Shizhou Yu Li Chen dejun Han Zhensheng Kang State Key Laboratory of Crop Stress Biology for Arid Areas Northwest A&F University Extension Center for Agricultural Technology Agriculture Department of Tibetan Autonomous Region

Wheat crops in China are constantly challenged by stripe rust. Deployment of cultivars with diverse resistances is the best strategy to control the disease. A recombinant inbred line(RIL) population derived from a cross between the resistant cultivar Chakwal 86 and susceptible landrace Mingxian 169 was studied in multiple environments to examine the underlying genetics and to identify quantitative trait loci(QTL) for stripe rust *** hundred and twenty-eight RILs were genotyped with wheat 35 K SNP array and a genome-wide linkage map with 1480 polymorphic SNP markers, or bins, was *** major QTL on chromosomes 1BL and 3BS, and one minor QTL on 6BS had significant effects in reducing stripe rust severity. The QTL were validated using composite interval mapping(CIM) and inclusive composite interval mapping(ICIM). These methods explained59.0%–74.1% of the phenotype variation in disease response. The QTL on chromosome 1 BL was confirmed to be Yr29/Lr46 and the one on 3BS was the resistance allele identified in CIMMYT germplasm but was not Yr30/Sr2. The QTL on 6BS probably corresponded to previously known QTL. RILs with combined QTL were more resistant than those with single or no QTL. Kompetitive allele-specific PCR(KASP) assays for the QTL with largest effect QTL on chromosome 3BS were performed on a subset of RILs and 150 unrelated wheat lines. The QTL on 3BS with its linked KASP markers can be used in marker-assisted selection to improve stripe rust resistance in breeding programs.

关键词： Genetic linkage Haplotype analysis QTL mapping Puccinia striiformis Single nucleotide polymorphism Triticum aestivum

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Improving hydrodynamic modeling of river networks by incorporating data assimilation using a particle filter

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International Journal of Sediment Research 2023年第5期38卷 711-723页

作者： Chenhui Jiang dejun Zhu Haobo Li Xiaoqun Liu Danxun Li State Key Laboratory of Hydroscience and Engineering Tsinghua University Hunan Institute of Water Resources and Hydropower Research

Numerical modeling is a well-recognized method for studying the hydrodynamic processes in river networks. Multi-source measurements also offer abundant information on the patterns and mechanisms within the processes. Therefore, improving hydrodynamic modeling of river networks through the use of data assimilation techniques has become a hot research topic in recent years. The particle filter(PF) is a commonly used data assimilation method and has been proven to be applicable to various nonlinear and non-Gaussian models. In the current study, an improved numerical hydrodynamic model for large-scale river networks is established by incorporating the advanced PF algorithm. Furthermore, the PF method based on the Gaussian likelihood function(GLF) and the method based on the Cauchy likelihood function(CLF) are compared for a complex river network scenario. The feasibility of the PF-based methods was evaluated through application to the Yangtze-Dongting River-lake Network(YDRN) by assimilating water stage data collected at six hydrometric stations during the entire hydrodynamic process in ***, the parameters used in the likelihood function, which affect the assimilation performance,also were explored in the current study. The study results found that the accuracy of the model-derived water stage data was improved when the PF-based methods are utilized, with improvement not only at the data assimilation(calibration) sites but also at three hydrometric stations not used in the data assimilation(i.e., verification sites). The highest average Nash-Sutcliffe Efficiency result for the six assimilation sites were 0.98 while the lowest summed root-mean-square-error result was 1.801 m. The comparison results also indicated that the CLF-based PF outperformed the GLF-based PF when highaccuracy observed data are available. Specifically, the CLF can effectively resolve the filtering failure problem and the dispersion problem of PFs, and further improve the accuracy of th

关键词： River networks Hydrodynamic process Particle filter Likelihood function

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