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多元连杆多种冲击方式载荷及响应特性分析

航空发动机 2024年第1期50卷 109-116页

作者：苏军田常棵安中彦刘亮亮吴法勇李岩中国航发沈阳发动机研究所沈阳110015

为了获取并分析多元连杆的冲击力以及各传力路径上的应变响应特征,采用气炮、悬臂落锤、液压等3种冲击加载方法对发动机多元连杆进行冲击加载。对冲击力和冲击应变响应曲线进行了时间域和频率域的特征分析,获取了冲击力和应变响应的波... 详细信息

为了获取并分析多元连杆的冲击力以及各传力路径上的应变响应特征,采用气炮、悬臂落锤、液压等3种冲击加载方法对发动机多元连杆进行冲击加载。对冲击力和冲击应变响应曲线进行了时间域和频率域的特征分析,获取了冲击力和应变响应的波形特征和频谱特征。通过与静载应变响应的对比获得动静响应系数,以及动静响应系数随波形宽度的变化规律。结果表明:在气炮、悬臂落锤、液压等3种冲击力的波形特征近似的情况下,在频谱上反映出各自不同的频率成分。在各传力路径上的冲击应变响应,除了响应幅值不同外,其余波形特征如峰值特征和频谱特性均较为一致。各应变之和作为连杆冲击力测试方法的表征参数,随波形中高频成分的增多,动静响应系数逐步增大。在进行多元连杆冲击载荷标定时,需要充分考虑所测试冲击力的载荷特征,选取合适的冲击载荷标定或者静载荷标定方法。

关键词：多元连杆冲击响应航空发动机

大束流阳极层离子源的阴极刻蚀现象及消除措施

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物理学报 2024年第18期73卷 230-241页

作者：汤诗奕马梓淇邹云霄安小凯杨东杰刘亮亮崔岁寒吴忠振北京大学深圳研究生院新材料学院深圳518055 香港城市大学物理与材料科学系中国香港999077 东北林业大学家居与艺术设计学院哈尔滨150006

阳极层离子源可输出高密度离子束流,广泛用于等离子体清洗和辅助沉积,但大束流下内部易发生放电击穿,且大量离子轰击内外阴极导致明显刻蚀,易造成样品污染.本文提出阳极环绕磁屏蔽罩和内外阴极溅射屏蔽板的设计方案,并仿真研究了其对离... 详细信息

阳极层离子源可输出高密度离子束流,广泛用于等离子体清洗和辅助沉积,但大束流下内部易发生放电击穿,且大量离子轰击内外阴极导致明显刻蚀,易造成样品污染.本文提出阳极环绕磁屏蔽罩和内外阴极溅射屏蔽板的设计方案,并仿真研究了其对离子源电磁场和等离子体放电输运的影响.发现阳极环绕磁屏蔽罩可切断离子源内部阴阳极间的磁场回路,消除打火条件.内外阴极溅射屏蔽板选择溅射产额低且绝缘性能好的氧化铝,既可阻挡离子溅射,又能屏蔽阴极外表面电场,使等离子体放电向阳极压缩,在抑制阴极刻蚀行为的同时提升离子输出效率.当距离阴极外表面9 mm时,溅射屏蔽板的作用效果最优,不仅能获得稳定放电和高效输出,还可大幅削弱阴极刻蚀行为并减少污染.实验结果显示:改进离子源无内部打火,输出高效且清洁,相同电流下离子输出效率较原离子源实际提高36%;玻璃基片在经过1 h清洗后,表面成分几乎不变,来自阴极溅射的Fe元素含量仅为0.03%,比原离子源低2个数量级,含量约为原离子源的0.6%,实验结果验证了理论分析.

关键词：大束流阳极层离子源阴极刻蚀电磁屏蔽输出性能

Steel-Making and Continuous/Ingot Casting Scheduling of Mixed Charging Plan Based on Batch Splitting Policy

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Journal of Iron and Steel Research International 2012年第4期19卷 17-21页

作者： liu Wei SUN liang-liang State Key Laboratory of Synthetical Automation for Process Industries Northeastern UniversityShenyang 110004 Liaoning China

For steel-making and continuous/ingot casting are the key processes of modern iron and steel enterprises, this paper proposes a batch splitting schedule policy to solve continuous and ingot casting schedule of mixed whole/ half charging plan for steel making. First establish the model of continuous and ingot casting schedule of mixed whole/half charging plan according to the complex constraints. Then solve this model by heuristic algorithm. Finally use actual data to prove the proposed algorithmrs validity and analyze the application result in steel plant.

关键词： continuous/ingot casiing whole/half charging batch splitting policy scheduling

Solving the Multi-discrete Logarithm Problems over a Group of Elliptic Curves with Prime Order

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Acta Mathematica Sinica,English Series 2005年第6期21卷 1443-1450页

作者： Jun Quan LI Mu Lan liu liang liang XIAO Academy of Mathematics and Systems Science Key Laboratory of Mathematics Mechanization Chinese Academy of Sciences Beijing 100080 P. R. China

In this paper, we discuss the expected number of steps in solving multi-discrete logarithm problems over a group of elliptic curves with prime order by using Pollard＇s rho method and parallel collision search algorithm. We prove that when using these algorithms to compute discrete logarithms, the knowledge gained through computing many logarithms does not make it easier for finding other logarithms. Hence in an elliptic cryptosystem, it is safe for many users to share the same curve, with different private keys.

关键词： Pollard's rho method Parallel collision search algorithm Elliptic curve Discrete logarithm Distinguished point

Methylation profile of bovine Oct4 gene coding region in relation to three germ layers

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Journal of Integrative Agriculture 2016年第3期15卷 618-628页

作者： ZHOU Xin-yu liu liang-liang JIA Wen-chao PAN Chuan-ying College of Life Sciences Northwest A&F University School of Computer Science & Engineering Jiangsu University of Science and Technology College of Animal Science and Technology Northwest A&F UniversityShaanxi Key Laboratory of Molecular Biology for Agriculture

Previous studies have shown that octamer-binding transcription factor 4（Oct4） plays a significant role in early embryonic development of mammalian animals, and different Oct4 expression levels induce multi-lineage differentiation which are regulated by DNA methylation. To explore the relationship between the methylation pattern of Oct4 gene exon 1 and embryonic development, in this work, five different tissues（heart, liver, lung, cerebrum and cerebellum） from three germ layers were chosen from low age（50–60 d） and advanced age（60–70 d） of fetal cattle and the differences between tissues or ages were analyzed, respectively. The result showed that the DNA methylation level of Oct4 gene exon 1 was significant different（P〈0.01） between any two of three germ layers in low age（〈60 d）, but kept steady of advanced age（P〉0.05）（〉60 d）, suggesting that 60-d post coital was an important boundary for embryonic development. In addition, in ectoderm（cerebrum and cerebellum）, there was no significant methylation difference of Oct4 gene exon 1 between low age and advanced age（P〉0.05）, but the result of endoderm（liver and lung） and mesoderm（heart） were on the contrary（P〈0.01）, which indicated the development of ectoderm was earlier than endoderm and mesoderm. The methylation differences from the 3rd, 5th and 9th Cp G-dinucleotide loci of Oct4 gene exon 1 were significantly different between each two of three germ layers（P〈0.05）, indicating that these three loci may have important influence on bovine embryonic development. This study showed that bovine germ layers differentiation was significantly related to the DNA methylation status of Oct4 gene exon 1. This work firstly identified the DNA methylation profile of bovine Oct4 gene exon 1 and its association with germ layers development in fetus and adult of cattle. Moreover, the work also provided epigenetic information for further studying bovine embryonic development and cellular reprogramming.

关键词： bovine DNA methylation octamer-binding transcription factor 4(Oct4) exon germ layer

The Faber Operator Acting on BMOA, BMO-Teichmüller Space and Chord-arc Curves

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Acta Mathematica Sinica,English Series 2024年第10期40卷 2359-2387页

作者： Tai liang liu Yu liang SHEN Department of Mathematics Soochow University

After reviewing Grunsky operator and Faber operator acting on Dirichlet space, we discuss the boundedness of Faber operator on BMOA, a new subject which turns out to be closely related to the BMO theory of the universal Teichmüller space. In particular, we show that the Faber operator acts as a bounded operator on BMOA if the symbol conformal map stays nearly to the base point in the BMO-Teichmüller space. Meanwhile, we obtain several results on quasiconformal mappings, BMOTeichm¨uller space and chord-arc curves as well. As by-products, this provides a complex analysis approach to the boundedness of the Cauchy integral acting on BMO functions on a chord-arc curve near to the unit circle in the BMO-Teichmüller space.

关键词： 30C62 30H35 32G15 BMO BMO-Teichmüller space BMOA Carleson measure Cauchy integral chord-arc curve Faber operator Grunsky operator quasicircle quasiconformal mapping

Nest decoration:Black feathers prevent Crested Mynas from nest usurpation

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Avian Research 2024年第2期15卷 292-297页

作者： Jinmei liu Wei liang Ministry of Education Key Laboratory for Ecology of Tropical Islands Key Laboratory of Tropical Animal and Plant Ecology of Hainan ProvinceCollege of Life SciencesHainan Normal UniversityHaikou571158China

Nests are important structures for birds to raise their offspring and for *** birds incorporate feathers into the nest,since feathers were traditionally thought to serve the function of *** in recent years have considered that some birds place feathers in conspicuous locations in the nest for decoration to trigger a fear response in the *** this study,we investigated whether decorative feathers could deter nest usurpation by Crested Mynas(Acridotheres cristatellus)by manipulating nest box *** results revealed that Crested Mynas preferred black feathers to white feathers as decorations and occupied nest boxes decorated with black feathers significantly less than those decorated with white feathers,suggesting that black decorative feathers in the nest could be more effective in preventing nest usurpation by Crested Mynas and that white decorative feathers may have other *** black feathers in the nest are prominently placed at the edge of the nest to convey the message that“this nest is occupied”or“the owner of this nest has been preyed upon”to visitor Crested Mynas,thus effectively preventing them from usurping the nest at a later stage.

关键词： Extended phenotype Feathers Nest decoration Nest usurpation

Geometrical transition properties of vortex cavitation and associated flow-choking characteristics in poppet valves

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 455-469页

作者： liang LU Zhongdong liang Yuming liu Zhipeng WANG Shohei RYU School of Mechanical Engineering Tongji UniversityShanghai 201804China Frontiers Science Center for Intelligent Autonomous Systems Tongji UniversityShanghai 201210China Technical Research Laboratory Hitachi Construction Machinery Co.Ltd.Tsuchiura 300-0013Japan

Poppet valves have become increasingly significant in ensuring precise digital flow rate and pressure control in hydraulic systems,necessitating a more profound understanding of the geometrical properties of cavitation in them,as well as associated flow-choking *** a comparative analysis with experimentally observed cavity images,we found that large eddy simulation(LES)turbulence modeling effectively replicates the geometrical properties of cavitation in these *** analysis demonstrated that cavitation is generated from vortices that result from the interaction between the notch contracta flow and the surrounding fluid *** in the internal or external vena contracta conditions result in fixed or discrete cavities,and the length-to-diameter ratio serves as a measure of the transition between internal and external vena contracta flow *** study establishes a threshold length-to-diameter ratio of approximately 2 for the tested poppet *** specifically,in notch structures with a smaller valve opening,longer sealing length,and smaller throttling angle(corresponding to a larger length-to-diameter ratio),the liquid-to-vapor transfer process is more evident than that in the reverse direction.A long-standing vapor cavity becomes fixed inside the notch,leading to a more pronounced flow-choking *** contrast,for structures with a smaller length-to-diameter ratio,the cavitation process for discrete vapor cavities is more complete,ensuring fluid flow continuity and significantly reducing the occurrence of the flow-choking phenomenon.

关键词： Poppet valves Vena contracta Vortex flow Vapor cavity Flow-choking

基于UPLC-Q-TOF-MS/MS的生脉饮(党参方)口服液化学成分分析

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中国现代中药 2024年第1期26卷 120-136页

作者：安琪武林芝侯丽华刘亮亮王知平孙红山西卫生健康职业学院药学院山西生物样品分析检测中心/仿制药一致性评价协同创新中心山西晋中030619

目的:采用超高效液相色谱串联四极杆飞行时间质谱法(UPLC-Q-TOF-MS/MS)对生脉饮(党参方)口服液中的化学成分进行定性表征。方法:选择ACQUITY UPLC?HSS T3色谱柱(150 mm×2.1 mm,1.8μm),以0.1%甲酸水溶液(A)-乙腈(B)为流动相梯度洗脱,流... 详细信息

目的:采用超高效液相色谱串联四极杆飞行时间质谱法(UPLC-Q-TOF-MS/MS)对生脉饮(党参方)口服液中的化学成分进行定性表征。方法:选择ACQUITY UPLC?HSS T3色谱柱(150 mm×2.1 mm,1.8μm),以0.1%甲酸水溶液(A)-乙腈(B)为流动相梯度洗脱,流速0.3 mL·min–1。采用电喷雾离子源,正、负离子全扫描模式下采集数据,扫描范围为m/z 50~1500。利用SCIEX OS-Q 1.6软件建立生脉饮(党参方)中单味中药材化学成分的本地数据库,将采集的化合物精确m/z和二级碎片离子信息与本地数据库及SCIEX OS-Q 1.6软件配置的中药二级数据库匹配,结合文献和对照品的相应信息进行化学成分表征。结果:共推断和鉴定了90个化合物,主要为黄酮类、皂苷类、苯丙素类、多炔类、有机酸类、生物碱等类及其他类成分,其中41个化合物来源于党参、33个化合物来源于麦冬、24个化合物来源于五味子。结论:建立了一种基于UPLC-Q-TOF-MS/MS对生脉饮(党参方)口服液中不同类型化合物进行鉴别的有效方法,为阐明其药效物质基础和提升其质量评价体系提供了参考。

关键词：生脉饮(党参方) 口服液超高效液相色谱-四极杆-飞行时间质谱法定性分析化学成分