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Predicting vibration signals of automobile engine using chaos theory

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Science China(Physics,Mechanics & Astronomy) 2004年第z1期47卷 93-98页

作者： LIU chun zhang Laibin WANG Zhaohui School of Mechanical and Electronic Engineering University of Petroleum Beijing 102249 China School of Mechanical and Electronic Engineering University of Petroleum Beijing 102249 China School of Mechanical and Electronic Engineering University of Petroleum Beijing 102249 China

Condition monitoring and life prediction of the vehicle engine is an important and urgent problem during the vehicle development process. The vibration signals that are closely associated with the engine running condition and its development trend are complex and nonlinear. The chaos theory is used to treat the nonlinear dynamical system recently. A novel chaos method in conjunction with SVD (singular value decomposition)denoising skill are used to predict the vibration time series. Two types of time series and their prediction errors are provided to illustrate the practical utility of the method.

关键词： engine, chaos, prediction, vibration series, singular value decomposition.

Numerical simulation on the microstress and microstrain of low Si-Mn-Nb dual-phase steel

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International Journal of Minerals,Metallurgy and Materials 2010年第2期17卷 173-178页

作者： Hai-feng Dong Jing Li Yue zhang Joongkeun Park qing-xiang Yang State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology Taejon 350-701 Korea

According to the stress-strain curves of single-phase martensite and single-phase ferrite steels,whose compositions are similar to those of martensite and ferrite in low Si-Mn-Nb dual-phase steel,the stress-strain curve of the low Si-Mn-Nb dual-phase steel was simulated using the finite element method（FEM）.The simulated result was compared with the measured one and they fit closely with each other, which proves that the FE model is *** on the FE model,the microstress and microstrain of the dual-phase steel were analyzed. Meanwhile,the effective factors such as the volume fraction of martensite and the yield stress ratio between martensite and ferrite phases on the stress-strain curves of the dual-phase steel were simulated,*** simulated results indicate that for the low Si-Mn-Nb dual-phase steel, the maximum stress occurs in the martensite region,while the maximum strain occurs in the ferrite *** effect of the volume fraction of martensite（fm） and the yield stress ratio on the stress-strain curve of the dual-phase steel is small in the elastic part,while it is obvious in the plastic *** the plastic part of this curve,the strain decreases with the increase of f_M,while it decreases with the decrease of the yield stress ratio.

关键词： dual-phase steel microstress microstrain numerical simulation finite element method(FEM)

Direct electrochemical reduction of solid vanadium oxide to metal vanadium at low temperature in molten CaCl_2-NaCl

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International Journal of Minerals,Metallurgy and Materials 2012年第6期19卷 499-505页

作者： Zhuo-fei Cai Zhi-mei zhang Zhan-cheng Guo Hui-qing Tang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing 100083 China

V205 sintered pellets and graphite rods were employed as the cathode and the anode, respectively; a molten CaC12-NaCI salt was used as the electrolyte. Then, V205 was directly reduced to metal vanadium by the Fray-Farthing-Chen （FFC） method at 873 K to realize low-temperature electrolysis. Two typical experimental conditions, electrolysis time and voltage, were taken into account to investigate the current efficiency and remaining oxygen content in electrolyzed products. The composition and microstmcture of the products were charac- terized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. SEM observations show that a higher voltage （1.8-3.4 V） and a longer electrolysis time （2-5 h） can improve the product quality separately, that is, a lower remaining oxygen content and a more uniform microstructure. The products with an oxygen content of 0.205wt% are successfully obtained below 3.4 V for 10 h. However, the current effi- ciency is low, and further work is required.

关键词： vanadium metallurgy vanadium pentoxide direct reduction electrolysis

A new trimeric furanocoumarin from Heracleum rapula

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Chinese Chemical Letters 2009年第9期20卷 1088-1090页

作者： Cun zhang YuanYan Liu Yong qing Xiao Li Li Institute of Chinese Materia Medica China Academy of Traditional Chinese Medicine Beijing 100700 China

A new trimeric linear-type furanocoumarin, rapultririn A （1）, was isolated from the underground part ofHeracleum rapula. The structure of this new compound was elucidated by NMR, MS spectroscopic methods. 2009 Yon... 详细信息

关键词： Heracleum rapula Tricoumarin Rapultririn A

3D Ni(Ⅱ)/Cu(Ⅱ) Supermolecular Frameworks Based on Pyridylamine and Fumarate Co-ligands Containing a Trinodal (4,5,6)-Connected Network and a (H2O)16 Water Cluster

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Chinese Journal of Chemistry 2013年第2期31卷 256-262页

作者： Yifan Kang qing Liu Wenting Yin Wentao zhang Ping Liu Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education Key Laboratory of Physico-Inorganic Chemistry of Shaanxi College of Chemistry and Material Science Northwest University Xi' an Shaanxi 710069 China

Two new complexes, [Ni（dpypda）（H2O）3].（fum）（l） and [Cu2（dpypda）2（fum）2],-8nH2O （2）（dpypda = N2,N4-di（pyridin-2-yl）pyrimidine-2,4-diamine, fum=fumarate）, have been synthesized and characterized by single-crystal X-ray diffraction. Complex 1 is a discrete unit, exhibiting a （4,5,6）-connected framework formed by hydrogen bonding interactions and electrostatic interactions between flee rum dianions and mononuclear [Ni（dpypda）（H2O）3]2＋ cations. However, in complex 2, two crystallographically independent rum dianions adopt the alternative mode of mixed monodentate bridging and chelating and bis（monodentate） bridging Cu（II） atoms to produce a one-dimensional （ID） infinite zigzag chain. And there are unique （H2O）16 water clusters which consist of one cyclic （H2O）4 tetramer and two cyclic （H2O）5 pentamer with six dangling water molecules in its 3D su- pramolecular framework. Both 1 and 2 are characterized by IR and elemental analysis, and the TG properties were also investigated for 2.

关键词： pyridylamine ligand fumarate anions hydrogen bonding water clusters

Empirical Likelihood Inference Under Stratified Random Sampling in the Presence of Measurement Error

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Acta Mathematicae Applicatae Sinica 2005年第3期21卷 429-440页

作者： Chang-chun Wu Run-chu zhang Department of Statistics School of Mathematics Nankai University Tianjin 300071 China Department of Mathematics Xiangnan University Chenzhou 423000 China

Suppose that several different imperfect instruments and one perfect instrument are used independently to measure some characteristic of a population. In order to make full use of the sample information, in this paper the empirical likelihood method is put forward for making inferences on parameters of interest under stratified random sampling in the presence of measurement error, Our results show that it can lead to estimators which are asymptotically normal and utilize all the available sample information. We also obtain the asymptotic distribution of empirical likelihood testing statistics. In particular, we apply the method to obtain estimator and confidence interval of population mean.

关键词： Empirical likelihood stratified random sampling measurement error empirical likelihood testingstatistic asymptotic normal asymptotical distribution

利用高密度电阻率法进行多年冻土探测的研究与应用

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地质与资源 2024年第3期33卷 339-348页

作者：杜海双王书明宋庆元周传芳殷启春张天恩孙桐中国地质调查局哈尔滨自然资源综合调查中心黑龙江哈尔滨150000 中国地质大学地球物理与空间信息学院湖北武汉430074

多年冻土退化后,融区周期性冻结和融化作用会严重损害输油管道的稳定性.为查明原油管道埋设区多年冻土分布、发育现状,计划分别采用二维、三维高密度电法进行探测.为了进一步研究高密度电法不同探测方式的有效性和冻土的电阻率响应特征... 详细信息

多年冻土退化后,融区周期性冻结和融化作用会严重损害输油管道的稳定性.为查明原油管道埋设区多年冻土分布、发育现状,计划分别采用二维、三维高密度电法进行探测.为了进一步研究高密度电法不同探测方式的有效性和冻土的电阻率响应特征,首先在管道下部空间建立未融化、半融化、贯穿融化3种模型,采用EarthImager 2D和EarthImager 3D软件进行有限单元法正演和圆滑约束的最小二乘法反演;随后根据数值模拟结果,对比研究3种模型电阻率响应特征及反演结果的差异性,总结二维、三维高密度电法勘探效果;最后利用勘探实例进一步验证.结果表明,高密度电法在多年冻土探测领域是一种行之有效的方法:二维高密度电法对未融化、贯穿融化探测效果优于半融化状态;三维高密度电法采集数据更加丰富,目标体形态展示更加直观精细,反演结果更加接近理论模型,适用各种冻土融化状态.野外实例进一步验证了数值模拟结果,三维高密度电法的应用也对多年冻土精细探测领域提供了新思路.

关键词：高密度电阻率法二维模型三维模型多年冻土原油管道

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老小水轮机组数字化系统建设探索与应用

四川水利 2024年第1期45卷 174-177页

作者：杨伟张青黄渝凯张民威何继全国电投重庆狮子滩发电有限公司重庆401220 北京中元瑞讯科技有限公司北京100085

传统水轮机组常受效率低下、设备老旧易损之困,限制水力发电可持续发展。为解决这些难题,文章提出了一种数字化裂纹预测系统,通过布置传感器和监测设备实时监测关键参数,可以更准确地评估机组性能,提升运行的可靠性和稳定性。从振动产... 详细信息

传统水轮机组常受效率低下、设备老旧易损之困,限制水力发电可持续发展。为解决这些难题,文章提出了一种数字化裂纹预测系统,通过布置传感器和监测设备实时监测关键参数,可以更准确地评估机组性能,提升运行的可靠性和稳定性。从振动产生、裂纹机理、征兆提取和智能诊断四个方面,针对老小水轮机组特点提出针对性处理方法,为在线诊断提供条件。以流态仿真与大数据模拟的方法,为故障提供模糊处理和诊断模型。实例仿真验证了该系统在振动故障诊断中的合理性。在此基础上,开发了水轮机组状态监测与故障诊断系统,实现了数据采集、信号分析、实时监测、异常参数或异常状态预警等功能。老小水轮机组数字化系统的建设和应用对解决我国水力发电设备老龄化现状具有一定参考价值。

关键词：数字化系统水轮机组寿命预测故障诊断

铸态Mg-9Gd-1.5Zn-xAl合金的显微组织和力学性能

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材料热处理学报 2024年第4期45卷 40-47页

作者：张震陈君陈晓亚李全安郭希宽王春阳河南科技大学材料科学与工程学院河南洛阳471023 有色金属新材料与先进加工技术省部共建协同创新中心河南洛阳471023

采用铸造法制备了Mg-9Gd-1.5Zn-xAl(x=0、0.3、0.8和1.3 mass%)合金,通过X射线衍射仪、光学显微镜、扫描电镜等研究了不同Al含量对Mg-9Gd-1.5Zn合金物相和显微组织的影响,并采用电子拉伸试验机测试了室温下4种合金的力学性能。结果表明... 详细信息

采用铸造法制备了Mg-9Gd-1.5Zn-xAl(x=0、0.3、0.8和1.3 mass%)合金,通过X射线衍射仪、光学显微镜、扫描电镜等研究了不同Al含量对Mg-9Gd-1.5Zn合金物相和显微组织的影响,并采用电子拉伸试验机测试了室温下4种合金的力学性能。结果表明:铸态Mg-9Gd-1.5Zn合金的组织由α-Mg基体和沿晶界分布的Mg_(5)Gd和(Mg,Zn)_(3)Gd相组成,加入Al元素后,合金组织中Mg_(5)Gd相逐渐减少,并产生了新相Al_(2)Gd、Al_(11)Gd_(3)和LPSO(Mg_(12)Gd(Al,Zn))。Al元素促进了有效异质形颗粒(Al_(2)Gd)的产生,抑制了晶粒长大,合金的组织明显细化,起到了细晶强化的效果。当Al添加量为0.8%时,合金的抗拉强度、屈服强度和伸长率分别为192.2 MPa、154.8 MPa和16.6%,与不含Al的Mg-9Gd-1.5Zn合金相比,分别提升了47.1%、64.8%和121.3%。

关键词： Mg-Gd-Zn合金 LPSO相显微组织力学性能