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COMPLEXITy.anD INTRANSITIVITy IN TECHNOLOGICAL DEVELOPMENT

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Journal of Systems Science and Systems Engineering 2014年第2期23卷 128-152页

作者： Alexander y.KLIMENKO The University of Queensland

This paper investigates the existence of a fundamental link between two disciplines that emerged during last few decades： complexity science and advanced engineering. During this time many industries, especially those related to the high-tech end of technological development, have faced the problem of increasing complexity of design, production and operation. Industrial projects have grown to become multidisciplinary, tightly interconnected, costly.and difficult to control and predict. Two trends can be identified in this respect： one is the consistent effort of systems engineering in reducing the uncertainties of complex industrial operations and the other is the effort undertaken in complexity studies to account for uncertainties present in the real world. In this work, we provide a brief overview of recent developments in advanced engineering and give a consistent interpretation of technological evolution from the perspective of complexity science in general and complex competitive systems （CCS） in particular. CCS is a general framework that was recently developed for analysis of complex systems involving competition. Transitivity of the decision-making process and the cyclic nature of technological progress are considered. Correctness of intransitive decisions is inherently relativistic： the same decisions can be seen as correct or incorrect when considered from different perspectives. When treated simplistically, intransitivity may seem to be illogical but, nevertheless, it is common in nature and needs to be studied. CCS provides a formalised scientific framework for analysis of intransitivity.and establishes the existence of an important connection linking complexity.and uncertainty with intransitivity. Implications of intransitivity for engineering decision-making and strategic planning are considered in the context of CCS. A working example of intransitivity in competition between major car mantifacturers is presented.

关键词： Complexity technology strategy systems engineering industrial strategy.and decision-making complex competitive systems.

Effect of Temperature on Material Transfer Behavior at Different Stages of Friction Stir Welded 7075-T6 Aluminum Alloy

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Journal of Materials Science & Technology 2013年第10期29卷 955-960页

作者： S.D.Ji y.y.Jin y.M.yue S.S.Gao y.X.Huang L.Wang Faculty of Aerospace Engineering Shenyang Aerospace University State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology

In this work, the morphologies of weld of 7075-T6 aluminum alloy via friction stir welding （FSW） were analyzed by optical microscopy, the temperature field was attained by numerical simulation, and the effect of temperature on material transfer behavior in the thermal-mechanical affected zone （TMAZ） at different stages was mainly investigated. The FSW process consists of three stages. It is very interesting to find that the maximum transfer displacement of material appears at the final stage of welding process, then at the stable stage and at the initial stage, which results from the difference of peak temperatures at different stages. At any stage, the material in TMAZ near the surface of weld transfers downwards, the material in the middle of weld moves upwards and the material near the bottom of weld hardly moves. In any cross section of weld, the largest transfer displacement of material appears in the middle of weld. The increase of rotational velocity.and the decrease of welding speed are both beneficial to the transfer displacement of material in the middle of weld.

关键词： Friction stir welding 7075-T6 aluminum alloy Thermal-mechanical affected zone Material transfer Numerical simulation

Frequency Veering of Rotating Metal Porous Twisted Plate with Cantilever Boundary Using Shell Theory

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Acta Mechanica Solida Sinica 2022年第2期35卷 282-302页

作者： y.y.Liu y.X.Hao W.Zhang L.T.Liu S.W.yang y.T.Cao College of Mechanical Engineering Beijing Information Science and Technology UniversityBeijing 100192China College of Mechanical Engineering Beijing University of TechnologyBeijing 100124China

The frequency veering of a metal porous rotating cantilever twisted plate with twist angle and stagger angle is *** porous materials may have the characteristics of gradient or uniform distribution along the thickness *** on the classical shell theory,considering the influence of centrifugal force produced by high-speed rotation,the free vibration equations of a rotating cantilever twisted plate are *** the polynomial function and Rayleigh-Ritz method,the natural frequencies and mode shapes of the metal porous cantilever twisted plate in both static and rotating states are *** accuracy of the present theory.and calculation results is confirmed by a comparison between them and the results available from the literature and those obtained from *** influences of the thickness ratio,porosity,twist angle,stagger angle and rotational velocity on the frequency veering and mode shape shift of the rotating cantilever twisted plate with porous material under three different distributions are *** should be mentioned that the frequency veering accompanied by mode shape shift occurs in both static and dynamic states.

关键词： Frequency veering Rotating twisted plate Cantilever boundary Metal porous

Nucleon-pair approximation with uncoupled representation

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Chinese Physics C 2021年第5期45卷 129-140页

作者： y.Lei y.Lu y.M.Zhao School of National Defense Science and Technology Southwest University of Science and TechnologyMianyang 621010China College of Physics and Engineering Qufu Normal UniversityQufu 273165China Shanghai Key Laboratory of Particle Physics and Cosmology School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of IFSA(CICIFSA) Shanghai Jiao Tong UniversityShanghai 200240China

In this paper,we propose an approach to nucleon-pair approximation(NPA)with m-scheme bases,in which the collective nucleon pairs are represented in terms of antisymmetric matrices,and commutations between nucleon pairs are given using a matrix multiplication that avoids angular-momentum couplings and *** the present approach significantly simplifies the NPA ***,it is formulated on the same footing with and without isospin.

关键词： uncoupled representation nucleon-pair approximation formalism computational efficiency

Mechanosynthesis and mechanochemical treatment of bismuth-doped vanadium phosphorus oxide catalysts for the partial oxidation of n-butane to maleic anhydride

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Journal of Natural Gas Chemistry 2008年第3期17卷 232-237页

作者： y. H. Taufiq-yap y.C. Wong y. Kamiya W.J. Tang Putra Center for Catalysis Science and Technology Department of Chemistry Faculty of Science Universiti Putra Malaysia 43400 UPM Serdang Selangor Darul Ehsan Malaysia Graduate School of Environmental Science Hokkaido Universit3 Sapporo 060-0810 Japan

Three Bi-doped vanadyl pyrophosphate catalysts were prepared via dihydrate route （VPD method）, which consisted of different preparation methods including mechanosynthesis, mechanochemical treatment, and the conventional reflux method. The catalysts produced by the above three methods were characterized by x-ray diffraction （XRD）, scanning electron microscopy （SEM）, and temperature programmed reduction （TPR）. Catalytic evaluation for the partial oxidation of n-butane to maleic anhydride （MA） was also carried out. The XRD patterns of all the Bi-doped catalysts showed the main peaks of pyrophosphate phase. Lower intensity peaks were observed for the mechanochemically treated Bi-doped catalyst （VPDBiMill） with two additional small peaks corresponding to the presence of a small amount of V5＋ phase. The TPR profiles showed that the highest amount of active oxygen species, i.e, V4＋–O- pair, responsible for n-butane activation, was removed from VPDBiMill. Furthermore, from the catalytic test results, the graph of selectivity to MA as a function of the conversion of n-butane demonstrated that VPDBiMill was the most selective catalyst. This suggests that the mechanochemical treatment of vanadium phosphate catalyst （VPDBiMill） is a potential method to improve the catalytic properties for the partial oxidation of n-butane to maleic anhydride.

关键词： mechanosynthesis mechanochemical treatment bismuth vanadyl pyrophosphate

MECHANICAL PROPERTIES OF Ti_3SiC_2 AT HIGH TEMPERATURE

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 465-470页

作者： y.W.Bao y.C.Zhou Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 ChinaShenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

Creep and stress relaxation behavior, the elastic modulus and fracture toughness of machinable Ti3SiC2 at various temperatures from 20 to 1250℃ were investigated by means of three-point bending tests. The experiments were performed respectively at: (i) fixed stress and changed temperatures, and (ii) fixed temperature and changed stresses. A creep resistance parameter that represents the probability of creep deformation in a given condition was defined as a function of both applied stress and the threshold stress, varying in a range from 0 to 1. Elastic modulus at high temperatures was measured through comparing relative slopes of loading curves in cyclic loading curve. The fracture toughness measured by SENB method showed a stable value in the range of 25-1000℃, but over 1000℃, it declined abruptly from -6.7MPa·m1/2 to -2.0MPa·m1/2 at 1200℃.

关键词： high-temperature Ti3SiC2 creep stress relaxation fracture toughness

EFFECT OF CHEMICAL COMPOSITION AND PROCESSES ON THE TEXTURE OF HOT-ROLLED DEEP DRAWING STEEL SHEET

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Acta Metallurgica Sinica(English Letters) 2002年第3期15卷 324-330页

作者： y.Chen X.Chen C.y.Li X.y.Li y.L.Kang Technical Center of Wuhan Iron and Steel Group Co. Wuhan 430080China Wuhan University of Science and Technology Wuhan 430080China Central General Iron and Steel Research Institute Beijing 100081China University of Science and Technology Beijing Beijing 100083China

A hot-rolled deep drawing(HDD)steel with high r-value and uniformdistribution of{111}texture in thickness was developed by hot rolling in ferrite region withlubricating between the roller and the *** experimental results show that the carbon contentand finish rolling temperature have significant effects on beneficial texture{111},and lubricatingduring hot rolling at low temperature in alpha-region makes the distribution of the *** basic requirements needed to meet for HDD steel were concluded by comparing differentcarbon contents and hot rolling processes.

关键词： ultra low carbon hot rolling in alpha-region lubricating r-value {111}texture

Research on Characteristics of Density Current Under the Action of Waves

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China Ocean Engineering 1997年第1期12卷 69-78页

作者： Li, DS Shen, y Ren, RS Chen, y HOHAI UNIV NANJING 210098PEOPLES R CHINA

In this paper, the characteristics of density current under the action of waves are described with the help of flume experiment and theoretical analysis. The study shows that turbid water under the action of the waves can present three types of motion, i. e. significant stratification, fragile stratification and strong mixing. The motion gf turbid;,ater presents significant stratification when (H/D)/root Delta rho/rho less than or equal to 4.5, generally this state is known as density current. The formulas of motion velocity, thickness, and discharge of density current moving on horizontal bottom are derived by use of basic equations such as momemtum equation, equation of energy conservation and continuity equation of fluid. The time-average velocity.and the thickness of density current under the action of waves have a relationship with such parameters as relative density (Delta rho/rho), wave height (H), and water depth (D). When these parameters are determined, the time-average thickness and motion velocity of density current are also determined. The relative thickness of density current (D-t/D) decreases with the increase of Delta rho/rho and increases with the increase of H/D. On the other hand, the motion velocity of density current increases with the increase of Delta rho/rho and decreases with the increase of the relative thickness (D-t/D) of density current. It is shown that the calculated results are in agreement with those of the flume experiment.

关键词： turbid current density current gravity current wave action motion velocity thickness

LOW CyCLE FATIGUE BEHAVIOR OF AZ91HP ALLOy IN AS HIGHP RESSURE DIE CASTING

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Acta Metallurgica Sinica(English Letters) 2000年第4期13卷 961-966页

作者： Liu, Z. Xu, y.y. Wang, Z.G. Wang, y. Liu, Z.y. Inst of Metal Research Chinese Acad of Sciences Shenyang China

Fully reversed total strain-controlled low-cycle fatigue tests were conducted at room temperature in air to study the fatigue behavior of AZ91HP magnesium alloy in as high pressure die casting and subsequently heat treatment. All the specimens in different heat histories exhibit cyclic strain hardening in different degrees. It is difficult to distinguish the fatigue behavior of the die casting specimens from that of the solution aging specimens. The solution treated specimens show longer fatigue life at high strain amplitude and shorter fatigue life at low strain amplitude than the die casting and solution aging specimens though they have the lowest yield strength with higher strain hardening. Fatigue fracture surfaces for strain amplitude larger than 0.005 show very similar to those found by monotonic tensile tests. The SEM examination reveals that the regions of fatigue crack growth and final fracture can be characterized by quasi-cleavage mechanisms, but some shallow dimples, slip bands and secondary cracks are found on the fracture surface in the fracture crack growth areas.

关键词： Cracks Die casting Fatigue of materials Heat treatment