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Design and performance analysis of position-based impedance control for an electrohydrostatic actuation system

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Chinese Journal of Aeronautics 2018年第3期31卷 584-596页

作者： Yongling FU Xu HAN Nariman SEPEHRI Guozhe ZHOU Jian FU liming yu Rongrong YANG School of Mechanical Engineering and Automation Beihang University Beijing 100083 China Department of Mechanical Engineering University of Manitoba Manitoba R3T 2N2 Canada China Academy of Launch Vehicle Technology Beijing 100076 China Flying College Beihang University Beijing 100083 China

Electrohydrostatic actuator（EHA） is a type of power-by-wire actuator that is widely implemented in the aerospace industry for flight control, landing gears, thrust reversers, thrust vector control, and space robots. This paper presents the development and evaluation of positionbased impedance control（PBIC） for an EHA. Impedance control provides the actuator with compliance and facilitates the interaction with the environment. Most impedance control applications utilize electrical or valve-controlled hydraulic actuators, whereas this work realizes impedance control via a compact and efficient EHA. The structures of the EHA and PBIC are firstly introduced. A mathematical model of the actuation system is established, and values of its coefficients are identified by particle swarm optimization. This model facilitates the development of a position controller and the selection of target impedance parameters. A nonlinear proportional-integral position controller is developed for the EHA to achieve the accurate positioning requirement of PBIC. The controller compensates for the adverse effect of stiction, and a position accuracy of 0.08 mm is *** experimental results are presented to verify the applicability of PBIC to the EHA. The compliance of the actuator is demonstrated in an impact test.

关键词： Actuation system Aerospace Electrohydrostatic actuator Force control Nonlinear dynamics Particle swarm optimization Position control

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The Journal of Biomedical Research 2016年第1期30卷 60-66页

作者： Mingzi Song Mingming Fang liming yu Yong Xu Departments of Pathophysiology and Nursing Jiangsu Jiankang Vocational University Key Laboratory of Cardiovascular Disease Department of PathophysiologyNanjing Medical University

Expression of P-selectin in injured or activated endothelia cells serves as a permissive step towards leukocyte recruitment and perpetuation of inflammation in the pathogenesis of atherosclerosis.P-selectin can be induced by pro-inflammatory stimuli via the transcription factor NF-κB,but the epigenetic mechanisms remain incompletely *** we reported that myocardin-related transcription factor A（MRTF-A）mediates the transactivation of a slew of adhesion molecules by oxidized low-density lipoprotein（oxLDL）,likely through a crosstalk with brahma-related gene 1（BRGl）,a chromatin remodeling ***,we show that MRTF-A was both sufficient and necessary for the transactivation of P-selectin gene in endothelial cells treated with TNF-α.Depletion of MRTF-A using small interfering RNA（siRNA）abrogated the binding of BRGl on the P-selectin *** of BRG1 up-regulated the activity of P-selectin promoter activity while BRGl knockdown attenuated P-selectin ***,BRGl silencing suppressed the accumulation of acetylated histone H3 and methylated histone H3K4,and altered the binding of NF-κB on the P-selectin ***,our data demonstrate an essential role for MRTF-A and BRGl in P-selectin transactivation in endothelial cells.

关键词： myocardin-related transcription factor A(MRTF-A) brahma-related gene 1(BRG1) P-selectin endothelial cell

晶界扩散Mg对钕铁硼磁体磁性能及微观组织的影响

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当代化工研究 2024年第11期 49-52页

作者：杨牧南钟淑伟余黎明天津大学材料科学与工程学院天津300000 江西理工大学稀土学院江西341000

烧结Nd-Fe-B磁体在风力发电、电动汽车等环保节能新能源产业中扮演着重要角色,因此研究制备高矫顽力及高磁能积的钕铁硼永磁材料是目前迫切需要解决的重要问题。本研究基于磁控溅射沉积非稀土元素Mg薄膜,再经过热处理使其扩散进入磁体内... 详细信息

烧结Nd-Fe-B磁体在风力发电、电动汽车等环保节能新能源产业中扮演着重要角色,因此研究制备高矫顽力及高磁能积的钕铁硼永磁材料是目前迫切需要解决的重要问题。本研究基于磁控溅射沉积非稀土元素Mg薄膜,再经过热处理使其扩散进入磁体内部,通过设定不同的扩散温度和时间,得到最佳扩散工艺参数,磁体矫顽力最大值达到17.12 kOe,增幅达到3.86 kOe,综合磁性能较为良好。通过对比分析实验前后磁体的磁性能和微观组织,Mg元素扩散过程中,低熔合金与富Nd相结合形成低熔液相,润湿性良好的低熔液相促进富Nd相流动,形成连续平滑的细晶界。这种方法可提高材料性能,适用于制备、表面改性和界面工程等领域。

关键词：烧结Nd-Fe-B磁体磁控溅射非稀土元素Mg 晶界扩散

Effect of strengthening mechanisms on mechanical properties of alumina-forming austenitic steel after pre-strain

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Progress in Natural Science:Materials International 2023年第6期33卷 901-910页

作者： Shengyu Zhang Qiuzhi Gao Wei Zhang Qingshuang Ma Hailian Zhang Jing Bai Huijie Zhang liming yu Huijun Li School of Materials Science and Engineering Northeastern University School of Resources and Materials Northeastern University at Qinhuangdao Daotian High Technology Co. Ltd. School of Materials Science & Engineering Tianjin University School of Mechanical Materials and Mechatronic Engineering University of Wollongong

Alumina-forming austenitic(AFA) steel, a promising candidate for use in high-temperature components of ultrasupercritical power plants, has high creep strengths and outstanding high-temperature corrosion resistance. The effects of microstructural evolution on the mechanical properties of Fe-20Ni-14Cr-3Al alumina-forming austenitic(3Al-AFA) steel with micro-cold deformation were investigated by multiple characterization methods, and the micro-cold deformation process was analyzed by conducting compression experiments. Tensile properties and hardness were also examined. The results show that the reduction of deformation has significant influences on the increase in the density of dislocation, the reduction of grain size, and the distribution of precipitates, which play an essential role in the enhancement of mechanical properties. As the reduction of deformation increases, the density of dislocations rises, the fragmentation of grains results in a reduction of grain size, and the distribution of precipitates at the grain boundaries gradually increases, which causes a rise in strength and a decrease in elongation. Since the elastic deformation range expands with an increase in deformation before the strain reaches 5 %of the CR0 sample in the compression test, the variation in the average grain aspect ratio between a reduction of 2% and 6 % is relatively small. It contributes more to hardness and strength when the grain aspect ratio is high.

关键词： Alumina-forming austenitic steel Pre-strain Mechanical properties Grain aspect ratio

下肢静脉血栓患者凝血因子Ⅺ水平及其与复发风险的相关性

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中华老年心脑血管病杂志 2024年第2期26卷 151-154页

作者：姜海军李荣华陈国平王丽侯军程小康于黎明西安大兴医院介入血管科 710016

目的探讨下肢静脉血栓患者凝血因子Ⅺ(FⅪ)水平及其与复发风险的相关性。方法选取2018年2月至2019年2月我院收治的下肢深静脉血栓(DVT)患者220例为研究组,选择同期健康体检者50例为对照组。随访3年,研究组最终纳入197例,根据限制性立方... 详细信息

目的探讨下肢静脉血栓患者凝血因子Ⅺ(FⅪ)水平及其与复发风险的相关性。方法选取2018年2月至2019年2月我院收治的下肢深静脉血栓(DVT)患者220例为研究组,选择同期健康体检者50例为对照组。随访3年,研究组最终纳入197例,根据限制性立方样条(RCS)结果将研究组分为低水平组94例(FⅪ12.1 U/L)。研究组于抗凝治疗结束1个月后、对照组于体检时,检测血浆中FⅪ水平并比较;采用Cox模型分析FⅪ对DVT复发的影响,RCS分析DVT复发与FⅪ水平的关系;Kaplan-Meier曲线分析不同FⅪ水平DVT的复发风险,并对研究组进行3年的随访。结果研究组FⅪ水平高于对照组(P12.1 U/L的患者,FⅪ平均值为13.8 U/L,风险比为1.38(95%CI:0.921~1.563)。Kaplan-Meier曲线分析结果显示,低水平组复发风险为28.62%(95%CI:25.633~31.609),中水平组复发风险为30.10%(95%CI:27.594~32.606),高水平组复发风险为38.06%(95%CI:34.306~41.371),3组之间显著相关(χ^(2)=6.631,P=0.036)。结论与健康人群比较,DVT患者血浆中FⅪ呈现高水平状态;随着FⅪ水平上升,患者DVT复发风险增高,可将10.3 U/L和12.1 U/L FⅪ水平节点作为DVT复发率明显升高的参考点。

关键词：静脉血栓形成因子Ⅺ 复发数据相关性比例危险度模型下肢深静脉

钕铁硼磁体表面双向脉冲电沉积Ni-Cr合金镀层工艺及耐腐蚀性能

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江西冶金 2024年第4期44卷 246-256页

作者：杨牧南罗三根邹雅茹余黎明天津大学材料科学与工程学院天津300072 江西理工大学稀土学院赣州341000 国瑞科创稀土功能材料(赣州)有限公司赣州341000

钕铁硼(NdFeB)磁体材料在新能源汽车、风力发电等领域广泛应用。但是,磁体易被腐蚀,不利于应用产品的稳定性。本研究采用双向脉冲电沉积技术,考察了不同的脉冲参数(pH值、电流密度、正向占空比、Cr盐浓度)对Ni基镀层耐腐蚀性能和微观结... 详细信息

钕铁硼(NdFeB)磁体材料在新能源汽车、风力发电等领域广泛应用。但是,磁体易被腐蚀,不利于应用产品的稳定性。本研究采用双向脉冲电沉积技术,考察了不同的脉冲参数(pH值、电流密度、正向占空比、Cr盐浓度)对Ni基镀层耐腐蚀性能和微观结构的影响。结果表明,在pH=4.5、电流密度为0.20 A/cm^(2)、正向占空比为60%、Cr盐含量为25 g/L的条件下,制备的Ni-Cr合金镀层具有优异的表面质量和良好的耐腐蚀性能,其电核转移电阻(R_(ct))值显著增至36990Ω·cm^(2),自腐蚀电位降至-707 mV,腐蚀电流密度仅为1.04×10^(-8)A/cm^(2)。本研究为提升NdFeB磁体的耐腐蚀性能提供了一种有效的方法及理论依据。

关键词：钕铁硼磁体双向脉冲电沉积工艺参数耐腐蚀性能

Nonlinear Simulations of the Bump-on-Tail Instabilities in Tokamak Plasmas

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Chinese Physics Letters 2021年第4期38卷 67-70页

作者： yumei Hou Wei Chen liming yu yunpeng Zou Min Xu Xuru Duan Southwestern Institute of Physics Chengdu 610041China

We reproduce nonlinear behaviors,including frequency chirping and mode splitting,referred to as bump-on-tail *** has been reported in previous works,the generation and motion of phase-space hole-clump pairs in a kinetically driven,dissipative system can result in frequency *** provide examples of frequency chirping,both with and without pure diffusion,in order to illustrate the role of the diffusion effect,which can suppress holes and clumps;Asymmetric frequency chirpings are produced with drag effect,which is essential to enhance holes,and suppress *** both diffusion and drag effect suppress the clumps,downward sweepings are observed,caused by a complicated interaction of diffusion and *** addition,we examine the discrepancies in frequency chirping between marginally unstable,and far from marginally unstable cases,which we elucidate by means of a dissipative *** addition,mode splitting is also produced via BOT code for a marginal case with large diffusion.

关键词： diffusion splitting dissipative

Selected multiferroic perovskite oxides containing rare earth and transition metal elements

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Chinese Science Bulletin 2014年第36期59卷 5170-5179页

作者： Shunbo Hu Lei Chen Yabei Wu liming yu Xinluo Zhao Shixun Cao Jincang Zhang Wei Ren Department of Physics Shanghai University

Multiferroic materials are currently the subject of intensive research worldwide, because of both their fundamental scientific problems and also possible technological applications. Among a number of candidates in the laboratories, compounds consisting of rare earth and transition metal perovskite oxides have very unusual structural and physical properties. In contrast to the so-called type I multiferroics, ferroelectricity may be induced by magnetic ordering or by applying external fields. In this review, the recent progress on the experimental and theoretical studies of some selected type II multiferroics is presented, with a focus on the perovskite oxides containing rare earth and transition metal elements. The rare earth orthoferrite crystals, rare earth titanate strained film, and rare earthbased superlattices are systematically reviewed to provide a broad overview on their promising electric, magnetic, and structural properties. The recent experimental advances in single-crystal growth by optical floating zone method are also presented. First-principles investigations, either supported by experimental results or awaiting for experimental verifications, are shown to offer useful guidance for the future applications of unconventional multiferroics.

关键词：钙钛矿型氧化物过渡金属元素稀土元素铁电性钙钛矿氧化物外部磁场结构特性实验室

基于GC×GC-TOFMS-O分析3种武夷岩茶的关键香气成分

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现代食品科技 2024年第6期40卷 221-230页

作者：胡腾飞萧涵谢贺陈国和欧行畅蒋容港王超李勤黄建安刘仲华虞丽明湖南农业大学茶学教育部重点实验室国家植物功能成分利用工程技术研究中心湖南长沙410128 植物功能成分利用省部共建协同创新中心农业农村部园艺作物基因资源评价利用重点实验室湖南长沙410128 武夷山九五茶叶有限公司福建南平354399

通过感官审评、全二维气相色谱-飞行时间质谱-嗅辨仪技术及香气活力值法,分析了三个茶树品种(肉桂、水仙、大红袍)毛茶在同一焙火温度下加工制成的三种武夷岩茶的关键香气成分。在香气品质上,肉桂以桂皮香为主,并带有花香;水仙以兰花香... 详细信息

通过感官审评、全二维气相色谱-飞行时间质谱-嗅辨仪技术及香气活力值法,分析了三个茶树品种(肉桂、水仙、大红袍)毛茶在同一焙火温度下加工制成的三种武夷岩茶的关键香气成分。在香气品质上,肉桂以桂皮香为主,并带有花香;水仙以兰花香为主;大红袍花果香馥郁。3种武夷岩茶中共检测出337种挥发性成分,36种香气活性成分、26种关键香气成分。其中,在肉桂、水仙、大红袍中分别确定17、16、18种关键香气成分。结合热图分析,肉桂中确定香叶醇、3,5-二乙基-2-甲基-吡嗪、异戊酸正己酯、正己醛等8个主要关键香气成分;水仙中确定己酸戊酯、罗勒烯、甲基庚烯酮、吲哚、3-乙基-2,5-甲基吡嗪等10个主要关键香气成分;大红袍中确定苯乙醇、苯甲酸甲酯、十一醛、2-甲基吡嗪、十二醛等8个主要关键香气成分,表明这些化合物对不同武夷岩茶香气品质的形成具有重要贡献。

关键词：武夷岩茶茶树品种全二维气相色谱-飞行时间质谱-嗅辨仪香气活力值法关键香气成分

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