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Investigation on the laser ablation of SiC ceramics using micro-Raman mapping technique

Journal of Advanced Ceramics 2016年第3期5卷 253-261页

作者： Chaoli fu Yong YANG Zhengren HUANG Guiling LIU Hui ZHANG fang JIANG Yuquan wei Structural Ceramic Engineering Research Center Shanghai Institute of CeramicsChinese Academy of Sciences 1295 Dingxi Road Shanghai 200050 China College of Environmental and Chemical Engineering Shanghai University 99 Shangda RoadShanghai 200444 China Structural Ceramic Engineering Research Center Shanghai Institute of CeramicsChinese Academy of Sciences 1295 Dingxi Road Shanghai 200050 China

Research on the laser ablation behavior of SiC ceramics has great significance for the improvement of their anti-laser ability as high-performance mirrors in space and lasers, or the laser surface micro-machining technology as electronic components in micro-electron mechanical systems (MEMS). In this work, the laser ablation of SiC ceramics has been performed by using laser pulses of 12 ns duration at 1064 nm. The laser induced damage threshold (LIDT) below 0.1 J/cm(2) was obtained by 1-on-1 mode and its damage morphology appeared in the form of 'burning crater' with a clear boundary. Micro-Raman mapping technique was first introduced in our study on the laser ablation mechanisms of SiC surface by identifying physical and chemical changes between uninjured and laser-ablated areas. It has been concluded that during the ablation process, SiC surface mainly underwent decomposition to the elemental Si and C, accompanied by some transformation of crystal orientation. The oxidation of SiC also took place but only in small amount on the edges of target region, while there was no hint of SiO2 in the center with higher energy density, maybe because of deficiency of O-2 atmosphere in the ablated area, elimination of SiO2 by carbon at 1505 degrees C, or evaporating at 2230 degrees C.

关键词： silicon carbide (SiC) laser ablation micro-Raman mapping technique decomposition oxidation

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High-temperature mechanical properties of near-eutectoid steel

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International Journal of Minerals,Metallurgy and Materials 2013年第9期20卷 829-834页

作者： Jun fu fu-ming Wang fang Hao Gui-xiang Jin State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The high-temperature mechanical properties of near-eutectoid steel were studied with a Cleeble-1500 simu- lation machine. Zero strength temperature （ZST）, zero ductility temperature （ZDT）, hot ductility curves, and strength curves were measured. Two brittle zones and one plastic zone were found in the temperature range from the melting point to 600℃. Embrittlement in zone I is caused by the existence of liquid film along dendritic interfaces. Ductility loss in zone Ⅲ mainly results from precipitates and inclusions as well as S segregation along grain boundaries. Pearlite transformation also accounts for ductility deterioration in the temperature range of 700-600℃. Moreover, the straightening temperature of the test steel should be higher than 925℃ for avoiding the initiation and propagation of surface cracks in billets.

关键词： carbon steel eutectic alloys high temperature properties mechanical properties brittleness straightening billets

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New chaos M-ary modulation method and its application in communications

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The Journal of China Universities of Posts and Telecommunications 2011年第1期18卷 77-83页

作者： fu Yong-qing ZHANG fang College of Information and Communication Engineering Harbin Engineering University Harbin 150001 China

At present, chaotic communications have been widely studied. However, these researches mainly focus on the binary systems while the researches of M-ary chaotic communications are not extensive. To change the situation, a chaos M-ary modulation method based on phase plane partition of Hamilton map is proposed. Firstly, the chaotic model of Hamilton map and its phase plane features are described, and then the way of creating the chaos M-ary modulation is discussed. Next, to evaluate the proposed method, the system simulation results and analysis are given. Finally, the chaos M-ary modulation method is applied to communications.

关键词： chaos M-ary modulation Hamilton map initial value mapping method phase plane partition

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Effect of Ordering Policies on Complex Dynamics Behaviours in a Discrete-Type Manufacturing Industry Supply Chain System

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Chinese Journal of Mechanical Engineering 2018年第6期31卷 195-206页

作者： Wen Wang wei-Ping fu Faculty of Mechanical and Precision Instrument Engineering Xi’an University of Technology

The beer game model is a typical paradigm used to study complex dynamics behaviours in production–distribution systems. The model, however, does not accord with current practical supply chain system models in discrete?type manufacturing industry, which are generally composed of retailers, distributors, manufacturers with internal sup?ply chain, and suppliers. To describe how ordering policies influence the complex dynamics behaviour modes and operating cost in a general discrete?type manufacturing industry supply chain system, a high dimension piecewise?linear dynamics model is built for the supply chain system. Five kinds of ordering policy combination are considered. The distribution of both the largest Lyapunov exponent of e ective inventory and average operating cost per cycle is obtained by simulation in a policy space. The simulation shows that for the general discrete?type manufacturing industry supply chain system, the upper chaotic corners emerge besides the lower chaotic corners in the policy space expressing the distribution of system behaviour mode, and that the ordering policies at each supply chain node as well as their combination have very significant e ect on the topology of the distribution of both system behaviour mode and operating cost in the policy space. We find that chaos is not always corresponding to high cost, and the "chaos amplification" is not completely relevant to the "cost amplification".

关键词： Supply chain system Ordering policy Operating cost Nonlinear dynamics behavior

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fuzzy-immune control strategy of a hydro-viscous soft start device of a belt conveyor

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Mining Science and Technology 2009年第4期19卷 544-548页

作者： XIE fang-wei HOU You-fu XU Zhi-peng ZHAO Rui School of Mechanical and Electrical Engineering China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China Test Branch of Beijing Coal Research Institute Beijing 100013 China

Considering the control difficulties of a hydro-viscous trol algorithm was derived. A fuzzy-immune PID controller was soft start （HVSS） device of a belt conveyor, a fuzzy-immune con- designed based on immune feedback regulations and adaptability of the fuzzy logic inference. Using MATLAB software, we simulated the controller and compared the HVSS device with a conven- tional PID controller and a fuzzy PID controller. The simulation results show that the controller is not only very reliable as a PID controller, robust and requires only a short adjustment time of fuzzy control, but possesses also capacity of global optimization of the immune algorithm. To verify our theoretical analysis and simulation, a HVSS test-bed was developed. The experimental results demonstrate that the fuzzy-immune PID controller managed to start the belt conveyor softly and to follow an S-shaped curve while the output speed correctly followed the preset speed with only small fluctuations in speed.

关键词： fuzzy-immune hydro-viscous soft-start control strategy belt conveyor PID

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Effect of thermal exposure time on tellurium-induced embrittlement of Ni–16Mo–7Cr–4Fe alloy

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Nuclear Science and Techniques 2017年第12期28卷 231-236页

作者： Xiang-wei Chu Hong-wei Cheng Cai-Tao fu Bin Leng Yan-Yan Jia fang Liu Zhi-Jun Li Shanghai Institute of Applied Physics Chinese Academy of ScienceJiading CampusShanghai 201800China School of Materials Science and Engineering University of Shanghai for Science and TechnologyShanghai 200093China National Center for Electron Microscopy in Beijing Tsinghua UniversityBeijing 100084China

The embrittlement of nickel-based structural alloys by fission-produced tellurium(Te) is a major challenge for molten salt reactors(MSR). In this study, the effects of thermal exposure time on tellurium diffusion in a candidate MSR structural alloy(Ni–16 Mo–7 Cr–4 Fe) and the consequent mechanical property degradation of the alloy were investigated through surrogate diffusion experiments at 700 °C. The results show that some tellurium reacted with the alloy to form tellurides on the surface,while some tellurium diffused into the alloy along grain boundaries. Ni_3Te_2 and CrTe were the most stable reaction products at the tested temperature, and the formation of CrTe on the surface induced the Cr depletion at grain boundaries of the alloy. The diffusion depth of Te increased gradually with thermal exposure time, and thediffusion rate kept stable within the test duration of up to3000 h. The Te diffusion in the alloy caused the embrittlement of grain boundaries, inducing crack formation and strength degradation in tensile test at room temperature.

关键词： Tellurium Grain boundary Embrittlement Intergranular cracking Nickel-based alloy Molten salt reactor

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Development of component stiffness equations for thread-fixed one-side bolt connections to an enclosed rectangular hollow section column under tension

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 568-586页

作者： fu-wei WU Yuan-Qi LI Department of Structural Engineering Tongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China

The derivation and validation of analytical equations for predicting the tensile initial stiffness of threadfixed one-side bolts(TOBs),connected to enclosed rectangular hollow section(RHS)columns,is presented in this *** unknown stiffness components are considered:the TOBs connection and the enclosed RHS ***,the trapezoidal thread of TOB,as an equivalent cantilevered beam subjected to uniformly distributed loads,is analyzed to determine the associated *** on the findings,the thread-shank serial-parallel stiffness model of TOB connection is *** analysis of the tensile stiffness of the enclosed RHS face due to two bolt forces,the four sidewalls are treated as rotation constraints,thus reducing the problem to a two-dimensional plate *** to the load superposition method,the deflection of the face plate is resolved into three components under various boundary and load *** to the plate deflection theory of Timoshenko,the analytical solutions for the three deflections are derived in terms of the variables of bolt spacing,RHS thickness,height to width ratio,***,the validity of the above stiffness equations is verified by a series of finite element(FE)models of T-stub *** proposed component stiffness equations are an effective supplement to the component-based method.

关键词： initial stiffness component based method thread-fixed one-side bolt rectangular hollow sections analytical equation

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Synthesis of a Photochromic Bisphenoxynaphthacenequinone Compound by Two-step Method

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Journal of Materials Science & Technology 1999年第2期15卷 190-192页

作者： fang, Zheng Liu, Jingyu fu, Liangshe Xu, Suxian fang, Tianru Chinese Acad Sci Changchun Inst Appl Chem Changchun 130022 Peoples R China

A new photochromic bisphenoxynaphthacenequinone compound, 6,6 prime - [1-methylethylidenebis (4,1-phenyleneoxy)] bis (5,12-naphthacenequinone) (1), was synthesized by a two-step method, i.e., synthesis of 6 [4-(2-(4-hydroxyphenyl) isopropyl) phenoxy)-5, 12-naphthacenequinone (2) from 6-chloro-5, 12-naphthacenequinone (3) and bisphenol-A, and a further reaction of compound 2 in DMF/acetone mixed solvent in the presence of anhydrous potassium carbonate and potassium iodide. The crude product was obtained in a precipitate form and can easily be purified by recrystallization. The solvent composition has marked influence on the yield of the precipitated crude product in the second step. (Edited author abstract) 3 Refs.

关键词： Light sensitive materials

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On Graphs with Cut Vertices and Cut Edges

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Acta Mathematica Sinica,English Series 2014年第3期30卷 539-546页

作者： Kun fu fang Jin Long SHU Faculty of Science Huzhou Teachers College Department of Mathematics East China Normal University

Let G（n,k,t） be a set of graphs with n vertices,k cut edges and t cut *** this paper,we classify these graphs in G（n,k,t） according to cut vertices,and characterize the extremal graphs with the largest spectral ra... 详细信息

关键词： Spectral radius extremal graph cut vertex cut edge

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Microstructures of Ti–Ni–Fe wire after severe cold-drawing and annealing

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Rare Metals 2013年第6期32卷 550-554页

作者： Hui-fang Geng fu-Shun Liu School of Material Science and Engineering Beijing University of Aeronautics and Astronatics

The microstructures and mechanical properties of Ti–47 at%Ni–3 at%Fe shape memory alloy wire under the condition of severe cold-drawing at room temperature and different postdeformation annealing processes were intensively investigated using transmission electron microscope(TEM),X-ray diffraction(XRD),Vickers microhardness tester and electron tensile *** is indicated that the structure of the alloy evolves into a predominant amorphous structure with a trace of nanocrystalline B2 phase after the cold-drawing of 76%areal *** annealing process exerted significant influence on the microstructure and mechanical *** occurs when the cold-drawn wire was annealed at 300℃ for 30 *** ultimate tensile strength and ductility as well as the superelasticity of the wire are improved significantly by cold-drawing plus postdeformation annealing.

关键词： Ti–Ni–Fe wire Severe plastic deformation Cold-drawing Annealing Amorphous structure

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