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Cladding of aluminum alloy 6061-T6 to mild steel by an electromagnetic tube bulging process: finite element modeling

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Advances in Manufacturing 2019年第1期7卷 73-83页

作者： zhi-Song Fan Su-Ting huang Jiang-hua deng School of Mechanical Engineering and Automation Fuzhou University Fuzhou 350116 People's Republic of China

Bimetal tubes have useful applications in various industries where service conditions demand more different requirements in the tube core than its outside surface. The recent use of electromagnetic forces to deform or join metallic workpieces at high speeds has undergone rapid growth for materials processing. However, to date, no sufficient systematic understanding of the underlying principles of a subsequent high-speed electromagnetic tube bulging process to manufacture bimetal tubes has been gained. In this work, magnetic pulse cladding of Al/Fe clad bimetal tubes was analyzed by finite element modeling (FEM) using ANSYS software. The validity of FEM analyses was first confirmed by experiments in terms of the deformed shape. Second, the effect of cladding parameters (such as axial feeding being the dominant factor in the multi-step process) on the bulging and thinning behavior of the Al clad tube was presented in detail. Both the numerical simulation and experimental results show that no more than 70% of the bulging-coil length is an appropriate amount for the feeding length to prevent defects from being introduced by non-uniform deformation in the transition zone of the Al clad tube. The distributions of the magnetic flux line, magnetic force, and plastic strain in different cladding steps were then analyzed. It was concluded that during the multi-step cladding process, there was an uneven distribution of the magnetic field force along the transition zone. Consequently, inharmonious plastic deformation behavior occurs, which results in a limited acceleration of the transition zone to a certain impact velocity.

关键词： Bimetal tubes Magnetic pulse cladding Finite element (FE) simulation Axial feeding

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Effect of Blockage Ratio on Heat Transfer and Pressure Drop in Rotating Ribbed Channels at High Rotation Numbers

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Journal of Thermal Science 2021年第3期30卷 902-913页

作者： deng Hongwu LI hua TAO zhi QIU Lu ZHU Jianqin National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics School of Energy and Power EngineeringBeihang UniversityBeijing 100191China

At high rotation numbers,the rotational effects on heat transfer and flow could be diverse among the channels with different blockage ***,most studies are conducted under low rotation number(less than 0.25)and selected blockage *** paper experimentally investigates the effect of rib blockage ratio(ranges from 0 to 0.3)on pressure loss and heat transfer in a rotating square channel under high rotation number(up to 0.81).The ribs staggered on leading and trailing walls were oriented 90°to the mainstream *** Reynolds number and the wall-to-fluid temperature ratio varied from 20000 to 40000 and 0.08 to 0.2,*** results showed that a larger blockage ratio resulted in a better heat transfer but a higher pressure *** optimum blockage ratio was 0.1 for the best thermal *** rotational effects were weakened in the passage with a higher blockage ratio,where the critical rotation number could not be ***,the heat transfer enhancement induced by rotation was more significant when the temperature ratio ***,the correlations were developed for the pressure drop and the convective heat transfer on the leading and trailing edges.

关键词： thermal performance rib blockage ratio high rotation number

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STUDY ON THE EFFECTS OF TLCP ON PYROLYSIS OF PET AND ITS RETARDANT MECHANISM

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Chinese Journal of Polymer Science 2008年第1期26卷 111-116页

作者： deng, Yi Wang, Yu-zhong Zong, zhi-jing Liu, Xiu-hua Du, Xiao-hua China Acad Engn Phys Mianyang 621900 Peoples R China Sichuan Univ Ctr Degradable & Flame Retardant Polymer Mat Chengdu 610064 Peoples R China

The flame retardancy of aromatic thermotropic liquid crystal phosphorus-containing copolyester,TLCP,on PET was *** results show that the presence of TLCP promotes char formation of the substrate and enhances thermal stability of char,hence delay its *** pictures show that the char formed from PET/TLCP is more compact, therefore is more resistant to fire and heat than that from pure *** gas analysis by I.R measurements indicates that TLCP would decompose to produce phosphor...

关键词： Thermotropic liquid crystal copolymer Flame retardant PET

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Influence of die geometry on self-piercing riveting of aluminum alloy AA6061-T6 to mild steel SPFC340 sheets

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Advances in Manufacturing 2019年第2期7卷 209-220页

作者： Jiang-hua deng Feng Lyu Ru-Ming Chen zhi-Song Fan School of Mechanical Engineering and Automation Fuzhou University Fuzhou 350116 People's Republic of China

The self-piercing riveting (SPR) process was used to join 2.0-mm-thick aluminum alloy 6061-T6 and 1.2-mm-thick mild steel SPFC340 sheets. SPR joints produced with a conventional flat-bottom die and conicalsection dies were investigated both experimentally and numerically. Lap shear tests were conducted under quasistatic conditions to evaluate the load-carrying capability of these SPR joints. The effect of variation in die geometry (such as variation in the die groove shape, cone height, and die radius) on the main mechanical response of the joints, namely the peak load and energy absorption, was discussed. The results showed that SPR joints produced with the conical-section dies exhibited a failure mode similar to those produced with a conventional die. All the joints failed by tearing of the top steel sheet. Cracks that occurred in the bottom aluminum alloy 6061-T6 sheet around the rivet leg were a result of tangential tensile stress. The cone height of a conical-section die is the most important parameter affecting the surface quality of Al/steel SPR joints. Conical-section dies with a moderate convex can ensure a good surface quality during the SPR process. In addition, SPR joints with single conical-section die allow higher tensile strength and energy absorption compared to those with double conical-section die.

关键词： Self-piercing riveting (SPR) Aluminum/steel dissimilar sheet Conical-section die Lap shear test

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Nondeterministic Fuzzy Simulation and Bisimulation

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Chinese Journal of Electronics 2020年第2期29卷 297-303页

作者： deng Hui LI zhi School of Electro-Mechanical Engineering Xidian University

As the abstraction and equivalent technologies, simulation and bisimulation have been applied to the simplifications of some classical and uncertain models structures. The studies of the more generalized simulation and bisimulation technologies have not proceeded *** this problem in mind, we introduce the concepts,lemmas, theorems of nondeterministic fuzzy simulation and bisimulation, as well as the relevant proofs. According to the definitions of nondeterministic fuzzy simulation and bisimulation, we propose nondeterministic fuzzy quotients and a series of quotienting algorithms to generate the minimization of nondeterministic fuzzy simulation and bisimulation. By comparison with previous quotienting algorithms, we show that our quotienting algorithms are more generalized. This kind of quotienting algorithms not only suit for Nondeterministic fuzzy Kripke structure(NFKS), but also Fuzzy Kripke structure(FKS)and classical Kripke structure.

关键词： Nondeterministic fuzzy kripke structure(NFKS) Nondeterministic fuzzy simulation Nondeterministic fuzzy bisimulation Nondeterministic fuzzy quotient

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Open-environment machine learning

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National Science Review 2022年第8期9卷 211-221页

作者： zhi-hua Zhou National Key Laboratory for Novel Software Technology Nanjing University

Conventional machine learning studies generally assume close-environment scenarios where important factors of the learning process hold invariant. With the great success of machine learning, nowadays, more and more practical tasks, particularly those involving open-environment scenarios where important factors are subject to change, called open-environment machine learning in this article, are present to the ***, it is a grand challenge for machine learning turning from close environment to open environment. It becomes even more challenging since, in various big data tasks, data are usually accumulated with time, like streams, while it is hard to train the machine learning model after collecting all data as in conventional studies. This article briefly introduces some advances in this line of research,focusing on techniques concerning emerging new classes, decremental/incremental features, changing data distributions and varied learning objectives, and discusses some theoretical issues.

关键词： machine learning artificial intelligence open-environment machine learning open ML

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连续血浆滤过吸附与连续血液透析改善ICU脓毒血症患者免疫水平效果分析

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海南医学院学报 2017年第12期23卷 1627-1629页

作者：杨远征胡志华邓小彦冼丽娜海南医学院第一附属医院重症医学科海南海口570102

目的:探讨连续血浆滤过吸与连续血液透析在治疗脓毒血症中的临床效果。方法:选取入院治疗的脓毒血症患者80例随机分为研究组和对照组,每组40例。两组患者均给予脓毒血症基础治疗,研究组给予连续血浆滤过吸附,对照组给予连续血液透析。... 详细信息

目的:探讨连续血浆滤过吸与连续血液透析在治疗脓毒血症中的临床效果。方法:选取入院治疗的脓毒血症患者80例随机分为研究组和对照组,每组40例。两组患者均给予脓毒血症基础治疗,研究组给予连续血浆滤过吸附,对照组给予连续血液透析。于治疗前后抽取采集患者的血标本,检测治疗前后两组患者的免疫细胞指标、炎症因子水平、APACHEⅡ评分和病死率统计,并进行比较分析。结果:两组治疗后各免疫水平均得到显著改善(P<0.05),然而研究组改善效果均显著优于对照组(P<0.05)。两组治疗后各炎症反应水平均得到显著改善(P<0.05),然而研究组改善效果均显著优于对照组(P<0.05)。两组治疗后的APACHEⅡ评分和病死率均存在统计学差异(P<0.05)。结论:连续血浆滤过吸附治疗在脓毒血症患者的血液净化治疗中效果更佳,具有临床应用价值。

关键词：脓毒血症连续血浆滤过吸附连续血液透析免疫临床效果

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Optimization of submerged entry nozzle parameters for ultra-high casting speed continuous casting mold of billet

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Journal of Iron and Steel Research International 2022年第1期29卷 44-52页

作者： Pei Xu Yong-zhi Zhou deng-fu Chen Mu-jun Long hua-mei Duan Laboratory of Metallurgy and Materials College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials Chongqing UniversityChongqing 400044China

Controlling the flow behavior in the mold in an appropriate way is the basis for realizing the billet ultra-high speed continuous *** on the new proposed physical water modeling experiment considering the effects of solidified shell and hydrostatic pressure,the flow behavior in the mold with cross section of 160 mm 9160 mm during continuous casting of billet is regulated by optimizing the inner diameters and immersion depths of submerged entry nozzle at the ultra-high casting speeds of 5.0–6.5 m/*** results show that under the premise of no slag entrainment,as well as uniform coverage and keeping good fluidity of liquid slag layer on the top free surface of the fluid in the mold,the appropriate parameters of submerged entry nozzle under the ultra-high casting speed of billet are 50 mm in inner diameter,95 mm in outer diameter and 180 mm in immersion *** on the basis of the obtained parameters of submerged entry nozzle,it can be known that the reasonable ranges of level fluctuation and impacting depth of the stream in the mold are about 0.82-1.11 and 593-617 mm,respectively.

关键词： Ultra-high casting speed Billet continuous casting Submerged entry nozzle Physical water modeling Flow behavior

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Infinitely Many Solutions to a Class of p-Laplace Equations

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Acta Mathematicae Applicatae Sinica 2019年第4期35卷 770-779页

作者： Yi-hua deng College of Mathematics and Statistics Hengyang Normal University

In this paper, we study a class of p-Laplace equations. Using variational methods, we prove that there are two solutions and one of these solutions is nonnegative. Using recurrence method, we prove that there are infi... 详细信息

关键词： p-Laplace equation variational methods infinitely many solutions nonnegative solution

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Why over-parameterization of deep neural networks does not overfit?

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Science China(Information Sciences) 2021年第1期64卷 242-244页

作者： zhi-hua ZHOU National Key Laboratory for Novel Software Technology Nanjing University

Deep neural networks often come with a huge number of parameters,even larger than the number of training examples,but it seems that these over-parameterized models have not suffered from *** is quite strange and why over-parameterization does not overfit?poses a fundamental question concerning the mysteries behind the success of deep neural networks.

关键词： Deep Neural Networks perspective AI Over-parameterization machine learning

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