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High-temperature Oxidation Behavior of Barrel Materials

Binggong Xuebao/Acta Armamentarii 2024年第4期45卷 1354-1362页

作者： Zhang, Cheng Zhang, Yuqi Wen, Xiangli bai, pengpeng Meng, Yonggang Ma, Liran Tian, Yu State Key Laboratory of Tribology Department of Mechanical Engineering Tsinghua University Beijing 100084 China National Joint Engineering Research Center forAbrasion Control and Molding of Metal Materials School of Materials Science and Engineering Henan University of Science and Technology Henan Luoyang 471003 China

With the increase in firepower strike requirements and the development of high-powered artillery, the high-temperature oxidation of barrel materials is becoming more and more serious, which seriously affects the performance of weapon and even leads to the scrapping of weapon. However, there is little research on the anti-oxidation performance of barrel materials at present. In this paper, the oxidation resistances and oxidation mechanisms of three barrel materials, i. e.,PCrNi3MoVA steel. 30SiMn2MoVA steel and MPS700 steel, at 600 ℃ in airare investigated. The cross-sectional morphology and phases of the oxide layers are analyzed by scanning electron microscopy, energy spectroscopy and X-ray diffractometry. The oxidation kinetics of three barrrel materials were analyzed. The results show that the oxide film thicknesses of the three steels gradually thicken and the rate of increaseinthickness gradually decreaseswith the increase in oxidation time. The oxidation kinetics curves of the three barrel materials are consistent with the parabolic growth kinetics law of oxide film. At 600 ℃, the internal oxide layer of PCrNi3MoVA steel forms an adhesive layer of a network structure consisting mainlyof Ni and Cr-richspinel oxides but theadhesive layerdoes not act as a barrier against oxidation. The inner layer of oxide layer of 30SiMn2MoVA steel is a porous aggregation zone of Si element oxide with a loose structure and relatively serious oxide flaking. The internal oxide layer of MPS700 steel forms a protective Cr-rich oxide layer that effectively prevents further oxidation. At the same time, Mo element stabilises the passivation film and indirectly improves oxidation resistance. Compared with PCrNi3MoVA steel and 30SiMn2MoVA steel, MPS700 steel can better form a dense oxidized layer under high temperature condition, so as to reduce the high temperature oxidation and wear degree of the matrix under high temperature conditions. MPS700 steel is more suitable for the preparation of long life and high reliability barrel. © 20

关键词： Alloying elements

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Improvement of hydrogen permeation barrier performance by iron sulphide surface films

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International Journal of Minerals,Metallurgy and Materials 2023年第9期30卷 1792-1800页

作者： pengpeng bai Shaowei Li Jie Cheng Xiangli Wen Shuqi Zheng Changfeng Chen Yu Tian State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China School of Mechanical Electronic&Information Engineering China University of Mining and Technology-BeijingBeijing 100083China State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing 102249China

Fe–S compounds with hexagonal crystal structure are potential hydrogen permeation barrier during H2S corrosion. Hexagonal system Fe–S films were prepared on carbon steel through corrosion and CVD deposition, and the barrier effect of different Fe–S films on hydrogen permeation was tested using electrochemical hydrogen permeation method. After that, the electrical properties of Fe–S compound during phase transformation were measured using thermoelectric measurement system. Results show that the mackinawite has no obvious barrier effect on hydrogen penetration, as a p-type semiconductor, and pyrrhotite (including troilite) has obvious barrier effect on hydrogen penetration,as an n-type semiconductor. Hydrogen permeation tests showed peak permeation performance when the surface was deposited with a continuous film of pyrrhotite (Fe_(1–x)S) and troilite. The FeS compounds suppressed hydrogen permeation by the promotion of the hydrogen evolution reaction, semiconducting inversion from p-to n-type, and the migration of ions at the interface.

关键词： hydrogen permeation barrier iron sulfide pyrrhotite semiconductor

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Robust scalable reversible strong adhesion by gecko-inspired composite design

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Friction 2022年第8期10卷 1192-1207页

作者： Xiaosong LI pengpeng bai Xinxin LI Lvzhou LI Yuanzhe LI Hongyu LU Liran MA Yonggang MENG Yu TIAN State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

Bio-inspired reversible adhesion has significant potential in many fields requiring flexible grasping and manipulation,such as precision manufacturing,flexible electronics,and intelligent robotics.Despite extensive efforts for adhesive synthesis with a high adhesion strength at the interface,an effective strategy to actively tune the adhesion capacity between a strong attachment and an easy detachment spanning a wide range of scales has been lagged.Herein,we report a novel soft-hard-soft sandwiched composite design to achieve a stable,repeatable,and reversible strong adhesion with an easily scalable performance for a large area ranging from~1.5 to 150 cm2 and a high load ranging from~20 to 700 N.Theoretical studies indicate that this design can enhance the uniform loading for attachment by restraining the lateral shrinkage in the natural state,while facilitate a flexible peeling for detachment by causing stress concentration in the bending state,yielding an adhesion switching ratio of~54 and a switching time of less than~0.2 s.This design is further integrated into versatile grippers,climbing robots,and human climbing grippers,demonstrating its robust scalability for a reversible strong adhesion.This biomimetic design bridges microscopic interfacial interactions with macroscopic controllable applications,providing a universal and feasible paradigm for adhesion design and control.

关键词： biomimetic design reversible adhesion composite cross-scale robotics

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MoS_(2) reinforced PEEK composite for improved aqueous boundary lubrication

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Friction 2023年第9期11卷 1660-1672页

作者： Xin HOU pengpeng bai Jingyang LI Yuanzhe LI Hui CAO Xiangli WEN Yonggang MENG Liran MA Yu TIAN State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

Polyether-etherketone(PEEK)is a corrosion-resistant material that has been widely used in aqueous lubrication.However,its anti-wear performance must be improved for its application in the industry.In this study,to improve the anti-wear performance of PEEK for aqueous boundary lubrication,PEEK/MoS_(2)composites were prepared by ball-milling and spark plasma sintering processes.A competitive MoS_(2)mechanism between the low shear strength property and the role of promoting wear debris generation influences the anti-wear performance of PEEK/MoS_(2)composites.Experiments demonstrated that the coefficients of friction(COF)and wear rate of PEEK composite with 0.25 wt%MoS_(2)were significantly reduced 68%and 94%,respectively.Furthermore,this was the first time that a PEEK composite could achieve a COF of less than 0.05 in aqueous boundary lubrication.Its anti-wear performance was verified to be better than that of PEEK/carbon fiber(CF)and Thordon composites.The PEEK/MoS_(2)composite may be a potential material for underwater equipment because of its outstanding anti-wear performance in aqueous boundary lubrication.

关键词： polyether-etherketone(PEEK)composite MoS_(2) anti-wear performance aqueous lubrication boundary lubrication

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基于强化学习的车道级可变限速控制策略

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交通信息与安全 2024年第1期42卷 105-114页

作者：白如玉焦朋朋陈越张瑶北京建筑大学通用航空技术北京实验室北京100044

针对高速公路合流区主线各车道交通流运行状况受合流车辆影响的差异性,研究了1种基于强化学习的车道级可变限速(differential variable speed limit,DVSL)控制策略。由于DVSL控制问题存在高维动作空间求解困难,本文利用限速变化值优化... 详细信息

针对高速公路合流区主线各车道交通流运行状况受合流车辆影响的差异性,研究了1种基于强化学习的车道级可变限速(differential variable speed limit,DVSL)控制策略。由于DVSL控制问题存在高维动作空间求解困难,本文利用限速变化值优化动作空间,确定状态空间以及考虑多因素的奖励函数;在求解过程中,使用优质经验回放技术(prioritized experience replay,PER)进行改进,以提高训练效率和模型性能;同时提出1种车道间的安全检测机制辅助PER-DDQN展开训练,保证车道级可变限速模型可实施性。利用SUMO仿真软件测试所提出策略的控制效果,结果表明:所提出的车道级可变限速策略相较于未实施可变限速控制场景,全程行程时间降低41.88%、平均速度提高5.65%,合流区行程时间降低66.91%、平均速度提高43.42%;且车道级可变限速控制策略下合流区内各车道拥堵时间明显缩短,速度变化更加平稳。此外,还测试了智能网联车(connected-automated vehicles,CAVs)在不同渗透率场景对所提出策略的影响,渗透率在低于60%时实施车道级可变限速策略控制效果明显优于未实施可变限速控制策略,在渗透率为20%、40%和60%的场景中平均全程行程时间分别降低了41.88%、13.38%和7.46%,平均速度提高了6.08%、2.36%和1.61%;当渗透率达到80%以上时,鉴于CAVs车辆能明显改善交通流状况,实施车道级可变限速控制策略改善效果不明显。

关键词：智能交通车道级可变限速控制策略强化学习高速合流区异质交通流

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Quantification/mechanism of interfacial interaction modulated by electric potential in aqueous salt solution

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Friction 2021年第3期9卷 513-523页

作者： Shaowei LI pengpeng bai Yuanzhe LI Noshir SPESIKA Yonggang MENG Liran MA Yu TIAN State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Department of Chemical and Biomolecular Engineering Tulane UniversityNew OrleansLA 70118USA

With the development of surface and interface science and technology,methods for the online modulation of interfacial performance by external stimuli are in high demand.Switching between ultra-low and high friction states is a particular goal owing to its applicability to the development of precision machines and nano/micro-electromechanical systems.In this study,reversible switching between superlubricity and high friction is realized by controlling the electric potential of a gold surface in aqueous salt solution sliding against a SiO_(2) microsphere.Applying positive potential results creates an ice-like water layer with high hydrogen bonding and adhesion at the interface,leading to nonlinear high friction.However,applying negative potential results in free water on the gold surface and negligible adhesion at the interface,causing linear ultra-low friction(friction coefficient of about 0.004,superlubricity state).A quantitative description of how the external load and interfacial adhesion affected friction force was developed,which agrees well with the experimental results.Thus,this work quantitatively reveals the mechanism of potential-controlled switching between superlubricity and high-friction states.Controlling the interfacial behavior via the electric potential could inspire novel design strategies for nano/micro-electromechanical and nano/micro-fluidic systems.

关键词： electrochemical potential reversible switching superlubricity nonlinear friction adhesion

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Synergistic lubricating effect of graphene/ionic liquid composite material used as an additive

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Friction 2021年第6期9卷 1568-1579页

作者： Lincong LIU Ming ZHOU Youtang MO pengpeng bai Qilin WEI Long JIN Shengli YOU Mingyue WANG Liangchuan LI Xin CHEN Xiao LI Yu TIAN School of Mechanical and Transportation Engineering Guangxi University of Science and TechnologyLiuzhou 545006China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China Department of Electromechain and Automotive Engineering Liuzhou City Vocational CollegeLiuzhou 535006China Chengdu Carbon Co. Ltd.Chengdu 610100China

We prepared a graphene/ionic liquid(G/IL)composite material by the hybridization of G and an IL for use as a lubricating oil additive.The friction coefficient and wear volume of a base oil containing 0.04 wt%of the G/IL composite was reduced by 45%and 90%,respectively.Furthermore,the base oil containing the G/IL composite exhibited better lubricating properties than the base oil containing G,IL,or a mixture of IL and G at the same mass fraction.A synergistic lubrication mechanism was also revealed.The G/IL composite was adsorbed and deposited on the wear surface,forming a more ordered protective film and a unique tribochemical reaction film during rubbing.Therefore,the G/IL composite exhibited the synergistic lubricating effects of G and IL,which significantly improved the lubricating performance of the base oil.This study also suggested a way to limit the out-of-plane puckering of G at the macroscale.

关键词： grapheme(G) ionic liquid(IL) synergistic lubrication protective films out-of-plane puckering mechanism

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烯效唑对盐碱胁迫下万寿菊生长及生理特性的影响

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草业科学 2024年第4期41卷 822-835页

作者：王燕蒋倩王亚丽陶甜甜汪雒璿杜鹏鹏白雪甘肃农业大学园艺学院甘肃兰州730070

为探究烯效唑对盐碱胁迫下万寿菊(Tagetes erecta)生长及生理特性的影响,以盆栽万寿菊植株作为试材,确定盐碱胁迫(NaCl꞉NaHCO3=1꞉1)的浓度(75 mmol·L^(−1)),后续以该筛选浓度进行试验。试验共设CK(叶面喷施去离子水)、T1(盐碱胁迫+0 mg... 详细信息

为探究烯效唑对盐碱胁迫下万寿菊(Tagetes erecta)生长及生理特性的影响,以盆栽万寿菊植株作为试材,确定盐碱胁迫(NaCl꞉NaHCO3=1꞉1)的浓度(75 mmol·L^(−1)),后续以该筛选浓度进行试验。试验共设CK(叶面喷施去离子水)、T1(盐碱胁迫+0 mg·L^(−1)烯效唑液)、T2(盐碱胁迫+25 mg·L^(−1)烯效唑液)、T3(盐碱胁迫+50 mg·L^(−1)烯效唑液)、T4(盐碱胁迫+75 mg·L^(−1)烯效唑液)、T5(盐碱胁迫+100 mg·L^(−1)烯效唑液)和T6(盐碱胁迫+125 mg·L^(−1)烯效唑液),共7个处理,测定其生长及生理指标,并用相关性和主成分分析对其结果进一步解析。结果表明:在生长过程中,盐碱胁迫至第12天时,万寿菊的地上部分及地下部分受到抑制,外源喷施75 mg·L^(−1)烯效唑显著缓解盐碱胁迫下万寿菊的地上及地下部分的生物量下降。随着盐碱胁迫至12 d时,叶绿素a(Chl a)含量、叶绿素b(Chl b)含量、叶绿素a+b(Chl a+b)含量、叶绿素a/b(Chl a/b)含量呈下降趋势,丙二醛(MDA)含量、相对电导率(REC)、过氧化物酶(POD)活性、脯氨酸(Pro)含量、可溶性糖(SS)含量呈上升趋势,超氧化物歧化酶(SOD)活性呈先升后降的趋势。相关分析表明,Chl a与Chl b、Chl a+b、Chl a/b呈极显著正相关关系(PT3>T5>T6>T2>T1,外源烯效唑在一定浓度下可缓解盐碱胁迫万寿菊幼苗的迫害程度,增强其抗性,增加其根系的活性,缓解盐碱胁迫对其生长造成的抑制现象,其中以75 mg·L^(−1)(T4)浓度效果最佳。

关键词：烯效唑盐碱胁迫渗透调节抗氧化酶万寿菊光合色素主成分分析

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高温环境Si_(3)N_(4)陶瓷与M50钢材料的球盘配副与润滑油量对摩擦学行为的影响研究

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摩擦学学报（中英文） 2024年第2期44卷 200-213页

作者：潘盈卓吕宝华马楷刘明辉程洁曹辉白鹏鹏孟永钢田煜中国矿业大学(北京)机电与信息工程学院北京100083 清华大学高端装备界面科学与技术全国重点实验室北京100084 中航机载系统有限公司北京100000 中国石化润滑油有限公司合成油脂研究院重庆400039 洛阳LYC轴承有限公司航空精密轴承国家重点实验室河南洛阳417023

针对耐高温轴承的高温润滑问题,采用SRV-Ⅳ微动摩擦磨损试验机对轴承用材料Si_(3)N_(4)陶瓷和M50钢展开了高温控油摩擦磨损试验,之后对不同的配副方式进行了高温足量油、乏油的摩擦磨损对比试验.控油试验结果表明:200℃、足量油润滑条件... 详细信息

针对耐高温轴承的高温润滑问题,采用SRV-Ⅳ微动摩擦磨损试验机对轴承用材料Si_(3)N_(4)陶瓷和M50钢展开了高温控油摩擦磨损试验,之后对不同的配副方式进行了高温足量油、乏油的摩擦磨损对比试验.控油试验结果表明:200℃、足量油润滑条件下,Si_(3)N_(4)(球)-M50(盘)配副相较于M50钢自配副具有更低的摩擦系数和盘磨损率.M50钢自配副磨损率更容易受到润滑油量的影响.这是由于Si_(3)N_(4)(球)-M50(盘)配副的M50盘表面在摩擦过程中生成了稳定的含磷摩擦反应膜,而M50钢自配副的磨损以磨粒磨损为主,化学反应膜容易被破坏,且磨粒浓度会受到润滑油量的影响.不同配副对比试验结果表明:200℃、3μL油量下,仅M50(球)-Si_(3)N_(4)(盘)配副长摩1 h未发生润滑失效,且能够保持较低的磨损率,除摩擦过程中产生的反应膜能够起到保护作用外,M50钢球表面化学反应膜成膜面积更小,成膜不易受乏油条件的影响也是重要原因.

关键词：耐高温轴承 M50钢 Si_(3)N_(4)陶瓷高温乏油

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中国人群关注花粉播报情况的多维度分析:一项国内大规模多中心横断面调查

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中华耳鼻咽喉头颈外科杂志 2024年第1期59卷 2-11页

作者：徐驰宇张彦书栾宁刘翔毅覃大洋王洪敏肖旭平周水洪张杰张萍白育青王蓬鹏齐岩孙中武刘壮巴罗王文超卢醒王旻郭睿孙德义陶立元朱丽北京大学第三医院耳鼻咽喉头颈外科北京100191 南京大学医学院附属盐城第一医院耳鼻咽喉科盐城224001 北京大学第三医院延庆医院耳鼻咽喉科北京102100 甘肃中医药大学附属医院耳鼻咽喉科兰州730030 广西钦州市第一人民医院耳鼻咽喉科钦州535000 朝阳市中心医院耳鼻咽喉科朝阳122000 湖南省人民医院耳鼻咽喉科长沙410005 浙江大学医学院附属第一医院耳鼻咽喉头颈外科杭州310003 贵州省仁怀市人民医院耳鼻咽喉科仁怀564500 内蒙古赤峰市敖汉旗医院耳鼻咽喉科赤峰024300 长治市人民医院耳鼻咽喉头颈外科长治046000 国家儿童医学中心首都医科大学附属北京儿童医院耳鼻咽喉头颈外科北京100045 首都医科大学宣武医院耳鼻咽喉头颈外科北京100053 北京航天总医院耳鼻咽喉头颈外科北京100076 北京大学第三医院延安分院(延安市中医医院)耳鼻咽喉科延安716000 西藏自治区人民医院耳鼻咽喉科拉萨850000 太原市中心医院耳鼻咽喉科太原030000 天津市环湖医院耳鼻咽喉头颈外科天津300350 北京大学人民医院耳鼻咽喉头颈外科北京100044 空军特色医学中心耳鼻咽喉科北京100042 大庆油田总医院耳鼻咽喉科大庆163001 北京大学第三医院流行病学研究中心北京100191

目的:多维度调查中国人群关注花粉播报情况,了解国内变应性鼻炎(allergic rhinitis,AR)患者的现状。方法:2022年3月1日至9月30日,国内21家医院共同开展一项基于问卷星平台的大规模多中心横断面调查,收集中国东北、华北、华东、华中、华... 详细信息

目的:多维度调查中国人群关注花粉播报情况,了解国内变应性鼻炎(allergic rhinitis,AR)患者的现状。方法:2022年3月1日至9月30日,国内21家医院共同开展一项基于问卷星平台的大规模多中心横断面调查,收集中国东北、华北、华东、华中、华南、西南、西北7个大区共7056名受试者的基本特征(包括社会人口学特征和其中AR患者的疾病特征),以及其关注花粉播报的情况、接收花粉播报的意愿和治疗满意率等。采用卡方检验、多变量线性回归及Logistic回归分析等统计学方法,多维度分析中国人群关注花粉播报的情况及相关影响因素。结果:所有7056名受试者中,关注过花粉播报的比例为23.02%。3176例自报AR患者和1019例花粉诱导的AR(pollen-induced AR,PiAR)患者中,关注花粉播报的比例分别为25.60%和39.16%,高于非AR和非PiAR受试者(χ^(2)值分别为21.74、175.11,P值均<0.001)。AR患者中,春、秋季过敏原阳性患者关注花粉播报的比例高于常年过敏原阳性患者(χ^(2)值分别为20.90、19.51,P值均<0.001);伴有哮喘、鼻窦炎、变应性结膜炎和心脑血管疾病的AR患者关注花粉播报的比例均高于不伴合并症的AR患者(χ^(2)值分别为50.83、21.97、56.78、7.62,P值均<0.05)。我国华北地区AR患者可在本地区查到花粉播报的比例为31.01%,显著高于其他大区(P值均<0.05)。多变量线性回归分析显示:PiAR患者中,家庭人均月收入较高、AR疾病认知水平较高、既往关注过花粉播报及合并变应性结膜炎者,接收花粉播报的意愿更强烈(B值分别为0.24、0.13、0.66、0.47,P值均<0.05);患者的疾病认知水平越高,主动参与治疗的意愿越强烈(R^(2)=0.72,P<0.001)。仅18.89%的AR患者对现有治疗效果满意;Logistic回归分析结果显示,关注过花粉播报的AR患者治疗满意率显著高于未关注者(OR=1.83,P<0.001)。结论:受疾病认知水平等多种因素影响,目前中国人群关注花粉播报情况欠佳;国内AR患者的治疗满意率不高。

关键词：花粉播报变应性鼻炎花粉诱导的变应性鼻炎过敏原回避多中心横断面调查

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