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Structure and wear resistance of TiN and TiAlN coatings on AZ91 alloy deposited by multi-arc ion plating 被引量:8
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作者 赵晖 王晓辉 +2 位作者 刘秋雷 陈立佳 刘正 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第B07期679-682,共4页
In order to investigate the microstructure of TiN and TiAlN coatings and their effect on the wear resistance of Mg alloy, TiN and TiAlN coatings were deposited on AZ91 magnesium alloy by multi-arc ion plating technolo... In order to investigate the microstructure of TiN and TiAlN coatings and their effect on the wear resistance of Mg alloy, TiN and TiAlN coatings were deposited on AZ91 magnesium alloy by multi-arc ion plating technology.TiN and Ti70Al30N coatings were prepared on the substrate,respectively,which exhibited dark golden color and compact microstructure.The microstructures of TiN and Ti70Al30N coatings were investigated by X-ray diffractometry(XRD)and scanning electron microscopy(SEM).The micro-hardness and wear resistance of TiN and Ti70Al30N coatings were investigated in comparison with the uncoated AZ91 alloy. The XRD peaks assigned to TiN and TiAlN phases are found.The hardness of TiN coatings is two times as high as that of AZ91 alloy, and Ti70Al30N coating exhibits the highest hardness.The wear resistance of the hard coatings increases obviously as result of their high hardness. 展开更多
关键词 AZ91 magnesium alloy TiN coating TiAlN coating multi-arc ion plating microstructure HARDNESS wear resistance
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Characteristics of non-thermal AC arcs in multi-arc generator 被引量:2
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作者 Qifu Lin Yanjun Zhao +5 位作者 Wenxue Duan Guohua Ni Xinyue Jin Siyuan Sui Hongbing Xie Yuedong Meng 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第12期255-267,共13页
To obtain large-volume non-thermal arc plasma(NTAP), a multiple NTAP generator with three pairs of electrodes has been developed. The arc plasma characteristics, including dynamic process, spatial distribution, and ro... To obtain large-volume non-thermal arc plasma(NTAP), a multiple NTAP generator with three pairs of electrodes has been developed. The arc plasma characteristics, including dynamic process, spatial distribution, and rotation velocity in the discharge zone, were investigated by high speed photograph and image processing methods. The results showed that the dynamic behaviors and spatial distribution of the arc plasma were strongly related to the electrode configuration.A swirl flow of multi-arc plasma was formed by adjusting the electrode configuration, and a steady luminance area was clearly observed in the center of the discharge zone. Moreover, the size of the luminance area increased by decreasing the gas flow rate. The electrical connection in series could be formed between/among these arc columns with their respective driving power supplies in the multi-arc dynamic evolution process. An approximately periodical process of acceleration and deceleration of the arc rotation velocity was observed in the multi-arc generator with swirl flow configuration. In general, the mean velocity of arc rotation was higher in the multi-arc generator with swirl flow configuration when a pair of electrodes driven by a power supply were opposite to each other rather than adjacent. 展开更多
关键词 CHARACTERISTICS multiple arc plasma multi-arc generator non-thermal arc
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EXPERIMENTAL STUDY ON SUPERFICIAL COAT OF GEARS OF NITRIDED 32Cr2MoV COATED WITH TiN FILM BY MULTI-ARC ION PLATING 被引量:2
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作者 LI Hui LI Runfang +1 位作者 XU Hongbin ZHANG Jin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2007年第4期52-56,共5页
After 32CrMoV is selected to manufacture nitrided gears coated with TiN by multi-arc ion plating, all of these uncoated gears and coated gears run in the gearbox under the same initial conditions so as to compare thei... After 32CrMoV is selected to manufacture nitrided gears coated with TiN by multi-arc ion plating, all of these uncoated gears and coated gears run in the gearbox under the same initial conditions so as to compare their difference concerning properties and microstructure. Experiment results indicate that tooth surface of the coated-TiN gears does not suffer surface abnormalities in meshed zone. Instead, the gears with nitrided case exhibit an abrasion mark on the meshed zone of tooth surface, which results in more weight loss of nitrided gears. The morphology of the surface suggests TiN film with more than 2 000 HV is so dense and smooth that coated-TiN gears have higher wear resistance compared with the uncoated gears. The microstructure of coated-TiN gears is finer, hardness is higher and its distribution of coated-TiN gears is more reliable than uncoated ones, which makes nitride layer combined with TiN film tightly. Consequently, the wear-resistance of gears has been dramatically promoted. 展开更多
关键词 GEAR multi-arc ion plating TiN Wear-resistance
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High temperature oxidation resistance of CrN/(Ti,Al,Zr,Cr)N bilayer films deposited by multi-arc ion plating 被引量:1
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作者 Shi-lu Zhao Zhen Zhang +3 位作者 Jun Zhang Jian-ming Wang Zheng-gui Zhang Shuang-hong Wang 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2017年第3期343-349,共7页
CrN/(Ti,Al,Zr,Cr) N bilayer films were successfully deposited on cemented carbide( WC-8% Co) substrates by multi-arc ion plating process using two Ti-Al-Zr alloy targets and one pure Cr target. As a result of bila... CrN/(Ti,Al,Zr,Cr) N bilayer films were successfully deposited on cemented carbide( WC-8% Co) substrates by multi-arc ion plating process using two Ti-Al-Zr alloy targets and one pure Cr target. As a result of bilayered structure and addition of alloying elements( e. g. Al and Cr),the films exhibited excellent high temperature oxidation resistance under both short-term isothermal( up to 800 ℃) and long-term cyclic( up to 600 ℃) exposure conditions. Combined with pre-established outstanding tribological properties( e. g. maximum hardness of 4 000HV0. 01 and maximum adhesion strength over 200 N),these observations make such films quite a promising candidate to extend the cutting tool life span and boost the performance in high-productivity,high-speed and high-feed cutting or in dry machining conditions. 展开更多
关键词 NITRIDE Bilayer film Cemented carbide multi-arc ion plating High temperature oxidation resistance
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Structure and Tribological Properties of CrTiAlN Coatings Deposited by Multi-Arc Ion Plating 被引量:1
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作者 田灿鑫 杨兵 +4 位作者 何俊 王红军 王泽松 王广甫 付德君 《Plasma Science and Technology》 SCIE EI CAS CSCD 2011年第1期55-60,共6页
CrTiAIN coatings were prepared by using a home-made industrial scale multi-arc ion plating system. The coatings were found to be composites of face-center-cubic CrN and TiN. The surface roughness, microhardness, and t... CrTiAIN coatings were prepared by using a home-made industrial scale multi-arc ion plating system. The coatings were found to be composites of face-center-cubic CrN and TiN. The surface roughness, microhardness, and tribological properties of the films were significantly affected by the nitrogen pressure and dc-pulsed bias voltage applied to the substrate. The CrTiA1N coatings with the smoothest surfaces were obtained at optimum conditions of nitrogen pressure of 5.0 Pa and bias voltage of -200 V. The samples were found to exhibit a hardness of 2900 HV0.05 with an average friction coefficient of 0.16 and wear rate of 1.5× 10^-16 m^3/N.m against cemented carbide. 展开更多
关键词 multi-arc ion plating CrTiAIN MICROHARDNESS surface morphology friction coellicient wear rate
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Dynamic characteristics of multi-arc thermal plasma in four types of electrode configurations 被引量:1
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作者 Yanjun ZHAO Guohua NI +6 位作者 Wei LIU Hongmei SUN Siyuan SUI Dongdong LI Huan ZHENG Zhongyang MA Chi ZHANG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2022年第5期183-194,共12页
The enhanced volume of thermal plasma is produced by a multi-arc thermal plasma generator with three pairs of discharge electrodes driven by three directed current power suppliers.Combined with a high-speed camera and... The enhanced volume of thermal plasma is produced by a multi-arc thermal plasma generator with three pairs of discharge electrodes driven by three directed current power suppliers.Combined with a high-speed camera and an oscilloscope,which acquire optical and electric signals synchronously,the dynamic behavior of different kinds of multi-arc discharge adjusted by the electrode arrangement is investigated.Also,the spatial distributions and instability of the arc discharge are analyzed in four electrode configurations using the gray value statistical method.It is found that the cathodic arcs mainly show a contracting state,while the anodic arcs have a trend of transition from shrinkage to a diffusion-like state with the increase of the discharge current.As a result of the adjustment of the electrode configuration,a high temperature region formed in the center of the discharge region in configurations of adjacent electrodes with opposite flow distribution and opposite electrodes with swirl flow distribution due to severe fluctuation of arcs.The discharge voltage rises with increased discharge current in this novel multi-arc plasma generator.It is also found that anode ablation mainly occurs on the conical surface at the copper electrode tip,while cathode erosion mainly occurs on the surface of the inserted tungsten and the nearby copper. 展开更多
关键词 multi-arc electrode configuration dynamic character EROSION
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MULTI-ARC BASIN SYSTEM OF THE KUNLUN OROGENIC BELT AND PAN-CATHYSIAN CONTINENTAL ACCRETION 被引量:1
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作者 YIN Fuguang, PAN Guitang and LI Xingzhen(Chengdu Institute of Geology and Mineral Resources, Chengdu, SC610081, China) 《Geotectonica et Metallogenia》 2003年第1期145-155,共11页
After Rodinia supercontinent was disintegrated in Late Proterozoic, an ocean, namely, Tethys Ocean, occurred between Gondwana continental group and Pan-Cathaysian continental group from Late Proterozoic to Mesozoic. F... After Rodinia supercontinent was disintegrated in Late Proterozoic, an ocean, namely, Tethys Ocean, occurred between Gondwana continental group and Pan-Cathaysian continental group from Late Proterozoic to Mesozoic. From Early Paleozoic to Mesozoic, Tethys Ocean was subducted toward Pan-Cathaysian block group, which results in backarc expansion, arc-land collision and forearc accretion. When the backarc basin expands and reaches the small oceanic basin, ophiolite melange will be generated. As accretion had already occurred in the south of the continental margin in the earlier stage, the succeeding backarc expansion and the frontal arc position were migrated toward south correspondingly. Therefore, multiple ophiolite belts and magmatic rock belts occurred, and show a trend of decreasing age from north toward south. As the continental margin was split and migrated toward south and reached a high latitude position, i.e., with the shortening and subduction of oceanic crust, the sedimentary bodies at high latitude was accreted continuously toward low latitude area together with the formation of oceanic island, mixing of cold-type and warm-type organism was generated. Moreover,blocks split and separated from Pan-Cathaysian or Gondwana continental group cannot traverse the oceanic median ridge and joins with another continental block. As a result, the Kunlun belt on the SW margin of the Pan-Cathaysian land was resulted from the multi-arc orogenesis such as the backarc seabed expansion, arc-arc collision, arc-land collision oceanic bed, and the continuous southward accretion process. 展开更多
关键词 multi-arc basin system Kunlun orogenic belt Pan-Cathaysian land continental accretion
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Oxidation behavior of TiAlZrCr/(Ti,Al,Zr,Cr)N gradient films deposited by multi-arc ion plating
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作者 Shilu ZHAO Jun ZHANG Changsheng LIU 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2010年第6期473-480,共8页
The two Ti-Al-Zr targets and one pure Cr target were used to prepare the TiAlZrCr/(Ti, Al, Zr, Cr)N gradient films on high speed steel (WlSCr4V) substrates by multi-arc ion plating technique. Short-term isothermal... The two Ti-Al-Zr targets and one pure Cr target were used to prepare the TiAlZrCr/(Ti, Al, Zr, Cr)N gradient films on high speed steel (WlSCr4V) substrates by multi-arc ion plating technique. Short-term isothermal (at 600 ℃, 700 ℃, 800℃ and 900 ℃ for 4 h) and long-terra cyclic (at 700℃ and 800℃ for 100 h) high temperature oxidation behavior of the gradient films were studied. Then the oxide scales formed on the film specimens were characterized by scanning electron microscopy (SEM), energy dispersion X-ray spectroscopy (EDS) and X-ray diffraction (XRD). It was showed that, under short-term isothermal condition, the high temperature oxidation resistance of the gradient film was excellent up to 800 ℃ and an oxide scale comprising TiO2 was observed. On the other hand, under long-term cyclic high temDerature condition, the oxidation resistance of the gradient film was excellent at about 700 ℃. 展开更多
关键词 multi-arc ion plating TiAlZrCr/(Ti Al Zr Cr)N gradient film High speed steel High temperature oxidation resistance
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Wear-resistance and anti-scuffing of multi-arc ion plating molybdenum films
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作者 WANG Hai-dou XU Bin-shi LIU Jia-jun ZHUANG Da-ming 《中国有色金属学会会刊:英文版》 CSCD 2004年第z1期391-394,共4页
The multi-arc ion plating technology was employed to prepare the molybdenum films with thickness of 3 μm on the AISI 1045 steel. The wear and scuffing tests were carried out on the ball-on-disc tester. AFM and SEM eq... The multi-arc ion plating technology was employed to prepare the molybdenum films with thickness of 3 μm on the AISI 1045 steel. The wear and scuffing tests were carried out on the ball-on-disc tester. AFM and SEM equipped with EDS were adopted to observe and analyze the morphologies and element compositions of surface,cross-section and worn scar of the Mo film. The phase structure was studied by XRD and the bonding strength between Mo film and substrate was measured by scratching tester. The tribological experiments show that the Mo film possesses a good wear-resistance and an excellent anti-scuffing property. The failure mechanism of Mo film under extreme condition is flaking off. 展开更多
关键词 multi-arc ion PLATING MOLYBDENUM film WEAR and SCUFFING
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STUDIES OF Cr-O THIN FILNS DEPOSITED BY MULTI-ARC ION PLATING
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作者 WANG Xjangdong, Beijing Vacuum Electronics Research Institute,Beijing 100016, China, and YUAN Lei Beijing Laboratory of Vacuum Physics, Academia Sinica, Beijing 100080, China 《真空科学与技术学报》 EI CAS CSCD 1992年第Z1期107-110,共4页
This paper presents the formation of Cr-O thin films on an iron substrate by multi-arc ion plating, which are intended to be used as a thermal radiation absorbent in electronic vacuum devices. Only oxygen was used as ... This paper presents the formation of Cr-O thin films on an iron substrate by multi-arc ion plating, which are intended to be used as a thermal radiation absorbent in electronic vacuum devices. Only oxygen was used as a reaction gas during deposition, the Cr-O thin film, must have high adhesion and low outgassing rate. The scratch test shows that the critical load, for an applicable Cr-O thin film deposited in oxygen atmosphere alone at a pressure of 8×10<sup>-1</sup> Pa, was as high as 6kg. 展开更多
关键词 CR ION STUDIES OF Cr-O THIN FILNS DEPOSITED BY multi-arc ION PLATING ARC
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STUDY ON HIGH TEMPERATURE PERFORMANCES OF MCrAlX COATINGS DEPOSITED BY MULTI-ARC ION PLATING 被引量:2
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作者 J. Zhang, J.B. Li, Q.Heng and X.H.Zhang Shenyang University,Shenyang 110044,China L.Q.Qi LiMing Aeroengine Manufacfruing Corperation, Shenyang 110043,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1999年第5期1019-1024,共6页
NCoCrAlSiYHf and CoNiCrAlTaY coatings which belong to protective Al 2O 3 scale forming type were deposited by multi arc ion plating technique . The effect of deposition process parameters on qualities of the coat... NCoCrAlSiYHf and CoNiCrAlTaY coatings which belong to protective Al 2O 3 scale forming type were deposited by multi arc ion plating technique . The effect of deposition process parameters on qualities of the coatings was discussed. The high temperature oxidation performances isothermal oxidation with 950℃ / 500h and 1100℃ / 100h were studied. And also, the hot corrosion performances at 700℃ and 800℃, with molten mixed salt composed of 75%wt Na 2SO 4 and 25%wt NaCl were investigated. Then the high temperature protection decaying mechanisms were proposed. 展开更多
关键词 multi arc ion plating superalloy coating isothermal oxidation hotcorrosion
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High-efficiency Gas Shielded Multi-arc Welding Technology 被引量:1
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作者 TANG Yingying ZHU Zhiming +1 位作者 YANG Zhongyu YU Yingfei 《电焊机》 2016年第11期9-20,共12页
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从单智能体到多智能体:大模型智能体支持下的激励型学习活动设计与实证研究 被引量:16
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作者 黄昌勤 钟益华 +2 位作者 王希哲 韩中美 魏同权 《华东师范大学学报(教育科学版)》 北大核心 2025年第5期44-56,共13页
大模型与智能代理技术的不断进步,使得大模型智能体成为教育领域中实现教与学提质增效的重要新工具。基于大模型智能体的功能定位差异,单一智能体虽然已能够针对各类教与学任务提供诸如内容生成、智能反馈与评估等支持,但单智能体的交... 大模型与智能代理技术的不断进步,使得大模型智能体成为教育领域中实现教与学提质增效的重要新工具。基于大模型智能体的功能定位差异,单一智能体虽然已能够针对各类教与学任务提供诸如内容生成、智能反馈与评估等支持,但单智能体的交互特点、功能属性具有较高同质性,在促进深层次认知发展方面存在一定局限。相比之下,多智能体能够通过模拟多种教育主体角色,提升学习互动的多样性和深度,进而实现更为个性化和深度的学习体验。鉴于智能体在学习过程中的应用主要依靠学习者自发性,为了保障学习活动的有效开展,本研究基于ARCS动机模型分别设计基于单智能体与多智能体的激励型学习活动方案,并面向英语阅读场景开展了准实验研究。实验结果发现:基于多智能体的激励型学习活动相较单智能体能够显著提升学生在推理、评价与应用方面的学习成绩,具有更强的学习动机,且有效促进了其深层次认知发展,尤其是抽象与概括能力。研究证明了多智能体在支持学生深度学习中的价值,为未来进一步探讨多智能体在教育中的应用提供了借鉴。 展开更多
关键词 大语言模型 多智能体 ARCS动机模型 激励型学习活动 深度学习
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多电极电弧焊接与增材制造技术的现状与未来趋势
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作者 胡青松 闫朝阳 +1 位作者 蒋凡 陈树君 《材料工程》 北大核心 2025年第5期17-34,共18页
针对成型件高精度控形与低损伤控性的实现需求,以及在增加熔敷量的同时达到热源热、质、力深度解耦的目标,多电极电弧焊接/增材技术已逐渐成为学术界与工业界共同关注的热点。本文对多电极电弧工艺的发展历程进行了系统综述,全面梳理了... 针对成型件高精度控形与低损伤控性的实现需求,以及在增加熔敷量的同时达到热源热、质、力深度解耦的目标,多电极电弧焊接/增材技术已逐渐成为学术界与工业界共同关注的热点。本文对多电极电弧工艺的发展历程进行了系统综述,全面梳理了多电极电弧焊接与增材领域的前沿研究成果,并对多电极电弧中不同类型的耦合电弧进行了分类总结,多电极电弧系统通过引入多个电极,实现了对耦合电弧热质力传输过程的更精细调控,有助于优化沉积层的成形质量,降低缺陷,提高制造精度。强调了不同类型多电极电弧工艺在热源和电极排布方式,热质力解耦传输特性的区别,总结了焊接过程参数对耦合电弧稳定性的影响机制,最后,本文提出了适用于电弧熔丝增材制造领域的多电极电弧特性,探索复合材料构件的高性能制造,搭建新型多电极电弧技术的工艺数据库,为耦合电弧和多电极电弧增材制造技术的应用推广提供有价值的参考。 展开更多
关键词 多电极电弧 电弧增材制造 热质传输 电弧特性 成形控制
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顾及空间特征的杆目标渐进式识别分类方法
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作者 田茂义 张佳琦 +2 位作者 刘如飞 张振虎 李子豪 《应用激光》 北大核心 2025年第2期132-140,共9页
针对车载激光点云部分缺失导致的杆柱漏识别、杆顶错分类的问题,提出一种顾及空间特征的杆目标渐进式识别方法。该方法利用级联随机森林模型以及空间关系特征,有效地解决了点云中断续杆目标的准确识别和分类问题。首先,通过级联结构的... 针对车载激光点云部分缺失导致的杆柱漏识别、杆顶错分类的问题,提出一种顾及空间特征的杆目标渐进式识别方法。该方法利用级联随机森林模型以及空间关系特征,有效地解决了点云中断续杆目标的准确识别和分类问题。首先,通过级联结构的上层模型在多尺度的节点切片中的圆弧形态特征获取垂直方向连续圆弧间的空间关系特征,结合圆弧形态特征实现断续杆柱的精确识别;其次,基于级联模型的杆柱识别结果,获取杆柱垂直簇的顶部聚类体,并通过空间关系约束的ESF形状特征获取杆柱与杆顶的空间特征,结合PCA维度特征利用级联模型实现杆顶准确分类。实验结果表明,该方法在两组实验数据中的识别准确率分别达到了96.56%和94.51%,能够有效应对复杂道路场景中杆目标的识别与分类问题,且具有较强的稳定性。 展开更多
关键词 杆目标 级联随机森林 多尺度切片 圆弧 空间特征
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配电网故障有源消弧M3C变流器多频组合对称环流控制方法
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作者 王文 张超峰 +4 位作者 岳雨霏 童宇轩 李俊杰 唐欣 曾祥君 《电网技术》 北大核心 2025年第7期2999-3008,I0094-I0102,共19页
模块化多电平矩阵式变换器(modular multi-level matrix converter,M3C)构成的AC-AC直接变流器无需中间直流级和高变压比升压变压器,将其应用在有源消弧装置中,可有效缩小体积和提升可靠性。当M3C输入输出同频时,变流器内部直流功率大... 模块化多电平矩阵式变换器(modular multi-level matrix converter,M3C)构成的AC-AC直接变流器无需中间直流级和高变压比升压变压器,将其应用在有源消弧装置中,可有效缩小体积和提升可靠性。当M3C输入输出同频时,变流器内部直流功率大大增加,造成桥臂电容电压易于发散和波动幅度差距大。传统方法通过注入多频组合的非对称环流实现桥臂能量平衡,但导致桥臂电容电压产生大小不一的波动,影响部分电容的寿命。针对此问题,该文提出基于对称环流注入的多频组合电容电压稳定控制方法,采用对称环流与共模电压多频分量组合,通过abc-ΣΔαβ0变换方法得到M3C电路等效解耦模型,并建立了有效的电容电压平均值与功率的反馈控制模型。仿真和半实物实验结果表明,当配电网发生单相接地故障时,M3C装置能够实现接地故障可靠消弧和各桥臂电容电压纹波相对均衡。 展开更多
关键词 有源消弧 模块化多电平矩阵式变换器 多频环流注入 共模电压
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基于扩展元结构的床身结构优化设计
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作者 李有堂 候宗仁 《机床与液压》 北大核心 2025年第18期47-51,58,共6页
床身作为机床的重要支撑件,其静、动态性能直接影响机床的加工精度与稳定性。为提高某立式加工中心床身的抗振特性,基于元结构理论,对元结构的扩展形式进行优化分析,基于此,提出一种设计床身结构的方法。结合床身内部结构特点提取元结... 床身作为机床的重要支撑件,其静、动态性能直接影响机床的加工精度与稳定性。为提高某立式加工中心床身的抗振特性,基于元结构理论,对元结构的扩展形式进行优化分析,基于此,提出一种设计床身结构的方法。结合床身内部结构特点提取元结构并进行优化分析,进一步优化扩展形式的元结构,确定具有更优传力性能的出砂孔形状;对上述两种方案的关键出砂孔尺寸进行多目标参数优化,将优化参数应用于床身进行结构设计与性能对比,证明扩展元结构法对于提升床身性能的优越性。结果表明:元结构法的优化参数改善了床身的静动态性能,但改善幅度不大;扩展元结构法的优化参数使得床身最大静变形的减小量与基频的提升量均大于元结构法,且在谐响应分析中,X、Y、Z方向上的波峰位置与幅值均发生不同程度的后移与下降,显著改善了床身的静动态性能。 展开更多
关键词 静动态性能 扩展元结构 圆弧式出砂孔 多目标尺寸优化
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高分辨率捕捉强间断多介质流场的伪弧长方法
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作者 李坤 马天宝 王渊芃 《兵工学报》 北大核心 2025年第10期334-347,共14页
可压缩多介质气液两相流中,介质热力学差异导致界面区域呈现强非线性波系干涉,显著增加数值模拟难度。尤其在双曲型守恒律方程框架下,流场易形成激波、接触间断和稀疏波等奇异结构,对算法精度、间断捕捉能力及稳定性提出更高要求。为此... 可压缩多介质气液两相流中,介质热力学差异导致界面区域呈现强非线性波系干涉,显著增加数值模拟难度。尤其在双曲型守恒律方程框架下,流场易形成激波、接触间断和稀疏波等奇异结构,对算法精度、间断捕捉能力及稳定性提出更高要求。为此,构建了一种面向多介质气液两相流场的高精度伪弧长方法,通过引入弧长参数将方程映射至正交弧长空间,缓解强间断导致的数值奇异性,并引入高阶重构格式保证解的精度。为精准刻画界面动力学行为,提出基于弧长空间的符号距离函数演化机制,并结合真实虚拟流体方法严格定义边界条件,确保界面物理量连续性。数值结果表明,该方法具备对强间断及复杂波系结构的高分辨率解析能力。 展开更多
关键词 多介质 双曲型守恒律方程 伪弧长方法 非线性 强间断
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CrAlN/TiAlN多层刀具涂层的制备及其性能
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作者 任俊泽 苏峰华 +1 位作者 李助军 刘怡飞 《中国表面工程》 北大核心 2025年第2期36-48,共13页
现代金属切削加工正向着高速、高精度和高效的方向发展,对刀具的性能有着越来越高的要求。利用表面技术对刀具表面进行改性,是提高刀具性能和寿命的有效途径。使用多弧离子镀膜技术在YG6硬质合金以及三刃立铣刀表面制备了Cr Al N/CrN/Cr... 现代金属切削加工正向着高速、高精度和高效的方向发展,对刀具的性能有着越来越高的要求。利用表面技术对刀具表面进行改性,是提高刀具性能和寿命的有效途径。使用多弧离子镀膜技术在YG6硬质合金以及三刃立铣刀表面制备了Cr Al N/CrN/Cr、TiAlN/CrN/Cr、Cr Al N/TiAlN/CrN/Cr三组涂层,并对三种涂层的制备技术、微观结构与性能差异、及耐磨与切削寿命提高机制进行研究。X射线衍射分析表明,三种涂层均为面心立方结构,其中TiAlN涂层表现出(200)晶面择优取向,而CrAlN和Cr Al N/TiAlN涂层则表现出(111)面的择优取向。使用显微硬度计和划痕仪对涂层的显微硬度和结合力进行测试,结果表明Cr Al N/TiAlN多层涂层的显微硬度和膜基结合力分别为2651 HV和59.2 N,显著高于TiAlN和CrAlN涂层。采用高温摩擦试验机评价了三种涂层的摩擦学性能,结果表明Cr Al N/TiAlN多涂层的摩擦性能优于TiAlN涂层和CrAlN涂层,室温下其平均摩擦因数和磨损率分别为0.603和2.92×10^(-6)mm^(3)(N·m)^(-1)。当温度增加到400℃时,Cr Al N/TiAlN涂层的平均摩擦因数进一步降低为0.467,磨损率增加至1.31×10^(-5)mm^(3)(N·m)^(-1)。铣削试验结果显示,TiAlN涂层刀具、CrAlN涂层刀具和Cr Al N/TiAlN涂层刀具的铣削寿命相对于无涂层刀具分别提升了80%、140%和200%,被加工样件的表面粗糙度分别降低至462 nm、415 nm和402 nm。研究结果表明Cr Al N/TiAlN涂层在现代切削加工领域有着良好的应用潜力。 展开更多
关键词 多弧离子镀 刀具涂层 多层涂层 CrAlN/TiAlN 切削性能
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多弧离子镀Tb_(70)Cu_(30)合金钕铁硼晶界扩散研究
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作者 马辰泽博 徐瑞 +9 位作者 李飞 唐晶晶 高青乐 尹高天 李慧 张帅 赵娜娜 刘树峰 鲁飞 游才印 《稀土》 北大核心 2025年第3期111-121,共11页
采用多弧离子镀在N50牌号烧结Nd-Fe-B磁体表面分别沉积Tb_(70)Cu_(30)合金扩散层和增重量0.32%~0.94%(质量分数)的Tb扩散层,进行扩散磁体制备。采用XRD、SEM、EDS、EPMA、PFM等分析手段表征扩散层物相组成、扩散磁体微观组织和磁性能。... 采用多弧离子镀在N50牌号烧结Nd-Fe-B磁体表面分别沉积Tb_(70)Cu_(30)合金扩散层和增重量0.32%~0.94%(质量分数)的Tb扩散层,进行扩散磁体制备。采用XRD、SEM、EDS、EPMA、PFM等分析手段表征扩散层物相组成、扩散磁体微观组织和磁性能。对比研究Cu元素加入对扩散磁体磁性能、微观结构及热稳定性的影响,结果表明离子镀Tb_(70)Cu_(30)合金扩散层与合金靶材物相组成、成分一致。在900℃扩散10h后,在500℃下回火4h,Tb_(70)Cu_(30)扩散磁体的矫顽力从13.47kOe提升至23.95kOe,剩磁仅降低0.18kGs,剩磁温度系数和矫顽力温度系数分别从-0.1394%/℃和-0.5961%/℃提升至-0.1194%/℃和-0.5214%/℃。相比Tb扩散磁体,在同等矫顽力提升幅度下,Tb_(70)Cu_(30)合金扩散处理Tb使用量同比降低0.22%(质量分数),Tb利用率达到25.56kOe/%(质量分数)。BSE-SEM和EPMA分析表明,Cu引入能够有效减少Tb在磁体近表层富集,抑制Tb晶内扩散和反常核-壳结构的形成,进而提升Tb元素扩散作用效果。 展开更多
关键词 钕铁硼 晶界扩散 多弧离子镀 Tb_(70)Cu_(30)合金 矫顽力
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