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Improving the high cycle fatigue property of Ti6Al4V ELI alloy by optimizing the surface integrity through electric pulse combined with ultrasonic surface rolling process

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Journal of Materials Science & Technology 2024年第3期170卷 103-121页

作者： pengfei sun Shengguan Qu Chenfeng Duan Xiongfeng Hu Xiaoqiang Li National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510640China School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510640China

To improve the surface integrity and high cycle fatigue property of Ti6Al4V ELI alloy,the electric pulse has been introduced into the ultrasonic surface rolling process(USRP),which is called electric pulse-assisted ultrasonic surface rolling process(EUSRP).With the help of“electroplasticity”of the electric pulse,the thickness of the surface gradient deformation layer was about three times of the USRP specimens by adjusting the pulse current ***,the surface hardness decreases due to the continuous effect of the pulse current and the“skin effect”during *** is worth noting that the higher the applied pulse current,the more severe the *** paradox causes the fatigue performance of EUSRP specimens lower than that of USRP *** break this paradox,the EUSRP treatment is followed by a USRP *** EUSRP-2(with a pulse current of 200 A)+USRP specimens exhibit excellent surface hardness,a gradient deformation layer thickness of about 400μm,low surface roughness and high compressive residual compressive ***,the hardening mechanisms of the different surface strengthening specimens have been quantitatively analyzed in combination with microstructure *** fatigue life of Ti6Al4V ELI alloy can be improved by about 25 times at 780 MPa using the EUSRP-2+USRP treatment,the main reason for the highest fatigue life is the deepest surface gradient layer and the deepest crack initiation *** fatigue limit of the EUSRP-2+USRP specimens is not the highest because too much surface hardening causes compressive residual stress relaxation during cycling and the beneficial effect of compressive residual stress is eliminated.

关键词： Ti6Al4V ELI alloy Combined surface treatment Transmission electron microscopy Residual stress Fatigue performance

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Mussel-inspired PTW@PDA composites for developing high-energy gun propellants with reduced erosion and enhanced mechanical strength

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Defence Technology（防务技术） 2024年第2期32卷 675-690页

作者： Xijin Wang Zhitao Liu pengfei sun Feiyun Chen Bin Xu Xin Liao School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuChina China North Industries Group Corporation Limited Beijing 100045China

The severe erosion and inadequate mechanical strength are prominent challenges for high-energy gun *** address it,novel PTW@PDA composites was prepared by polydopamine(PDA)-modifying onto potassium titanate whisker(PTW,K_(2)Ti_(6)O_(13)),and after was incorporated into gun propellant as erosion-reducing and mechanical-reinforcing *** interfacial characterizations results indicated that as-prepared PTW@PDA composites exhibits an enhanced surface compatible with propellant matrix,thereby facilitating their dispersion into propellants more effectively than raw PTW *** to original propellants,PTW@PDA-modified propellants exhibited significant less erosion,with a Ti-Kbased protective coating being detected on the eroded *** 0.5 wt%and 1.0 wt%addition of PTW@PDA significantly improved impact,compressive and tensile strength of *** the inevitably reduction in relative force,PTW@PDA slightly increase propellant burning rate while exerting little adverse impact on propellant dynamic *** strategy can provide a promising alternative to develop high-energy gun propellant with less erosion and more mechanical strength.

关键词： High energy gun propellant Potassium titanate whiskers Polydopamine modification Erosion inhibitors Mechanical reinforcing fillers

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Microphysical Insights into a Tornadic Supercell from Dual-Polarization Radar Observations in Jiangsu, China on 14 May 2021

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Journal of Meteorological Research 2024年第2期38卷 303-320页

作者： Chao YUAN Yang BAI pengfei sun Hua BAI Lu XIA China Meteorological Administration Tornado Key Laboratory Foshan 528315 Institute of Atmospheric Environment China Meteorological AdministrationShenyang 110166 Panjin National Climate Observatory Panjin 124010 Yangzhou Meteorological Bureau of Jiangsu Province Yangzhou 225100 Yichun Meteorological Bureau of Heilongjiang Province Yichun 153000

Tornadoes are incredibly powerful and destructive natural events,yet the microphysical characteristics of the parent storm and its effects on tornadogenesis remain *** study analyzed polarization radar data of a tornadic supercell that occurred in Jiangsu Province of China on 14 May 2021,in comparison with another tornadic supercell and two non-tornadic supercells that occurred in the same region in *** two tornadic supercells exhibited lower differential reflectivity(ZDR)in the hook echo region compared with the non-tornadic supercells,indicating smaller median drop sizes.A distinct increase in ZDR from the melting of frozen hydrometeors,observed between2.5-and 4.0-km altitude in the non-tornadic storms,was absent in the tornadic *** non-tornadic supercells also displayed substantially higher specific differential phase(KDP)below the melting level,likely aroused from enhanced melting and *** findings suggest fundamental microphysical contrasts between tornadic and nontornadic ***,tornadic supercells have smaller droplets and may reduce melting in hook ***,greater separation between the ZDR arc and the KDP foot was observed during *** vertical gradient of KDP related to the cooling pool strength of the hook echo,regulating rear-flank downdraft *** the limited number of cases investigated,the findings of this study indicate that monitoring ZDR,KDP,and drop size distribution trends could assist with tornado prediction and warnings.

关键词： tornado polarimetric radar supercell hook echo drop size distribution

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Efficient photocatalytic biomass-alcohol conversion with simultaneous hydrogen evolution over ultrathin 2D NiS/Ni-CdS photocatalyst

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Chinese Chemical Letters 2024年第7期35卷 422-427页

作者： Zongyi Huang Cheng Guo Quanxing Zheng Hongliang Lu pengfei Ma Zhengzhong Fang pengfei sun Xiaodong Yi Zhou Chen State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China College of Materials Key Laboratory of High Performance Ceramic Fibers(Xiamen University)Ministry of EducationXiamen UniversityXiamen 361005China Technology Center China Tobacco Fujian Industrial Co.Ltd.Xiamen 361021 China

The photocatalytic conversion of biomass into high-value chemicals,coupled with simultaneous hydrogen(H_(2))evolution,leveraging the electrons and holes generated by solar energy,holds great promise for addressing energy *** this study,we constructed a dual functional photocatalytic system formed by NiS loaded on Ni doped two-dimensional(2D)CdS nanosheet(NiS/Ni-CdSNS)heterostructure for visible-light-driven H_(2)evolution and ethanol oxidation to ***,the 2D NiS/NiCdSNS exhibited significant activity and selectivity in both photocatalytic H_(2)evolution and ethanol oxidation,achieving yields of 7.98 mmol g^(-1)h^(-1)for H_(2)and 7.33 mmol g^(-1)h^(-1)for *** heterogeneous interface of the composite facilitated efficient charge separation,while NiS provided abundant sites for proton reduction,thereby promoting the overall dual-functional photocatalytic *** functional theory calculations further reveal that both Ni doping and NiS loading can reduce the reaction energy barrier of ethanol oxidation of free radicals,and NiS/Ni-CdSNS composite materials exhibit stronger ethanol C-H activation ability to generate key intermediate·CH(OH)CH_(3)on the *** work serves as a valuable guide for the rational design of efficient dual functional photocatalytic systems that combine H_(2)evolution with the selective conversion of organic compounds into high-value chemicals.

关键词： Photocatalysis Biomass-alcohol oxidation H_(2)evolution Dual-functional catalysis

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Magnesium doping to improve the light to heat conversion of OMS-2 for formaldehyde oxidation under visible light irradiation

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Chinese Chemical Letters 2024年第4期35卷 193-198页

作者： Tingting Liu pengfei sun Wei Zhao Yingshuang Li Lujun Cheng Jiahai Fan Xiaohui Bi Xiaoping Dong College of Chemistry and Chemical Engineering Zhejiang Sci-Tech UniversityHangzhou 310018China College of Environmental Science and Engineering Nankai UniversityTianjin 300071China Hangzhou Kaiming Catalyst Co. Ltd.Hangzhou 310013China

Mg-doped manganese oxide octahedral molecular sieve(Mg-OMS-2)catalysts were prepared by hydrothermal *** photothermal degradation performance of these catalysts for formaldehyde(HCHO)in batch system and continuous system was *** light absorption of OMS-2 was increased by Mg-doped,especially for near infrared light,which promoted surface temperature reach a maximum of 214.8℃ under xenon *** this temperature,the reinforced surface lattice oxygen and oxygen vacancy that formed by lattice distortion via Mg-doped were *** best HCHO elimination efficiency was achieved over Mg_(0.2)/OMS-2 catalyst with Mg^(2+)/Mn^(2+)=1/5,which could reduce HCHO from 250 ppm to 10 ppm within 20 *** in situ DRIFTS was also carried out to monitor the changes in the content of reaction intermediates and analyze the degradation paths of *** was found the HCHO was attacked by formed·OH and·O^(2-) to generate formate species and carbonate species,and finally transformed to CO_(2) and H_(2)*** photothermal catalytic oxidation process exhibited a high efficiency purification of HCHO without the help of extra energy consumption.

关键词： Mg doping Photothermal catalysis OMS-2 HCHO Reaction mechanism

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Importance of periphytic biofilms for carbon cycling in paddy fields:A review

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Pedosphere 2024年第1期34卷 36-43页

作者： Lei ZHOU Yonghong WU Junzhuo LIU pengfei sun Ying XU Jan DOLFING Robert GMSPENCER Erik JEPPESEN State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Zigui Three Gorges Reservoir Ecosystem Observation and Research Station of Ministry of Water Resources of the People's Republic of ChinaYichang 443605China College of Nanjing University of Chinese Academy of SciencesNanjing 211135China Faculty of Energy and Environment Northumbria UniversityNewcastle upon Tyne NE18QHUK Department of Earth Ocean and Atmospheric ScienceFlorida State UniversityTallahassee FL 32306USA Department of Ecoscience&Centre for Water Technology(WATEC) Aarhus UniversityAarhus DK-8000Denmark Sino-Danish Centre for Education and Research Beijing 100049China Limnology Laboratory Department of Biological Sciences and Centre for Ecosystem Research and Implementation(EKOSAM)Middle East Technical UniversityAnkara 06800Turkiye Institute of Marine Sciences Middle East Technical UniversityMersin 33731Turkiye

Paddy fields play an important role in global carbon(C) cycling and are an important source of methane(CH_(4)) emissions. Insights into the processes influencing the dynamics of soil organic C(SOC) in paddy fields are essential for maintaining global soil C stocks and mitigating climate change. Periphytic biofilms composed of microalgae, bacteria, and other microorganisms are ubiquitous in paddy fields, where they directly mediate the transfer of elements at the soil-water interface. However, their contributions to C turnover and exchange have been largely neglected. Periphytic biofilms affect and participate in soil C dynamics by altering both abiotic(e.g., pH and redox potential) and biotic conditions(e.g., microbial community composition and metabolism). This review summarizes the contributions of periphytic biofilms to soil C cycling processes, including carbon dioxide fixation, SOC mineralization, and CH_(4) emissions. Future research should be focused on: i) the mechanisms underlying periphytic biofilm-induced C fixation and turnover and ii) quantifying the contributions of periphytic biofilms to soil C uptake, stabilization, and sequestration in paddy fields.

关键词： carbon fixation carbon mineralization carbon sequestration methane emission microbial aggregates soil organic carbon

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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 *** 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 *** 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%,*** 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 *** calcu-lated contribution of each strengthening mechanism to the yield strength and theoretical calculations were in good agreement with the experimental *** 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

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Copper(Ⅰ)-catalyzed interrupted click/radical relay:A four-component modular synthesis of triazole sulfones

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Chinese Chemical Letters 2024年第3期35卷 247-251页

作者： pengfei sun Fang Wei Chen-Ho Tung Zhenghu Xu Key Lab for Colloid and Interface Chemistry of Education Ministry Shandong UniversityJi'nan 250100China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China Functional Molecules of Zhejiang Province School of ScienceWestlake UniversityHangzhou 310024China Key Laboratory of Organic Chemistry in Jiangxi Province Institute of Organic ChemistryJiangxi Science&Technology Normal UniversityNanchang 330013China

A new,four component copper(Ⅰ)-catalyzed interrupted click/radical relay cascade has been *** unprecedented interrupted click reaction provides a rapid modular synthesis of triazole sulfones,important privileged heterocyclic pharmacophores which cannot be accessed by a traditional click *** interception of cuprate-triazole,the key reaction intermediate formed in situ,is an important feature of this process.

关键词： Click reaction Triazole Sulfone Radical relay

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貂皮贸易与明末建州女真的崛起

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西部皮革 2024年第14期46卷 138-140页

作者：孙鹏飞武汉理工大学马克思主义学院

文章主要研究了明中后期东北地区的貂皮贸易，特别是貂皮贸易的起源和发展历程，及其对明朝、朝鲜和建州女真的影响。文章通过分析历史文献，如《明英宗实录》《万历野获编》《明史》等，探讨貂皮贸易的起源和影响。研究认为，貂皮贸易... 详细信息

文章主要研究了明中后期东北地区的貂皮贸易，特别是貂皮贸易的起源和发展历程，及其对明朝、朝鲜和建州女真的影响。文章通过分析历史文献，如《明英宗实录》《万历野获编》《明史》等，探讨貂皮贸易的起源和影响。研究认为，貂皮贸易不仅促进了建州女真的崛起，还对明朝和朝鲜产生了深远的影响。

关键词：貂皮建州女真明朝朝鲜

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风-车-桥气动干扰作用下的汽车纵横向协调控制

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中国机械工程 2024年第4期35卷 731-741页

作者：袁志群李曰瀚林立孙鹏飞张义厦门理工学院机械与汽车工程学院厦门361024 福建省客车先进设计与制造重点实验室厦门361024 福建省风灾害与风工程重点实验室厦门361024

为提高跨海大桥上轿车的风致行车安全能力,采用合成风和动网格耦合方法建立了轿车超越集装箱货车的瞬态分析模型,揭示了“风-车-桥”气动交互作用机理及其对轿车气动特性的影响规律。采用五次多项式插值算法建立了超车轨迹规划模型,基... 详细信息

为提高跨海大桥上轿车的风致行车安全能力,采用合成风和动网格耦合方法建立了轿车超越集装箱货车的瞬态分析模型,揭示了“风-车-桥”气动交互作用机理及其对轿车气动特性的影响规律。采用五次多项式插值算法建立了超车轨迹规划模型,基于模糊逻辑的双PID控制方法与径向基神经网络的滑模控制方法设计了纵横向协调控制器,开展了轿车超车过程的路径跟踪能力分析及行驶稳定性评价。研究结果表明:风-车-桥的气动干扰大小与行驶车道及位置有显著关系,纵横向协调控制器的路径跟踪控制精度和鲁棒性较好,轿车侧风稳定性提高效果明显。

关键词：超车气动干扰侧风稳定性路径跟踪运动控制器

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