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DEADLOCK-FREE SCHEDULING METHOD BASED ON PETRI NET AND GA

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Chinese Journal of Mechanical engineering 2003年第4期16卷 371-375页

作者： Xu Gang Wu Zhimingschool of Automation,shanghai jiaotong university,shanghai 200030, china school of Automation Shanghai Jiaotong University Shanghai 200030 China

An efficient algorithm for finding an optimal deadlock-free schedule in amanufacturing system with very limited buffer is presented. This algorithm is based on the effectivegenetic algorithm (GA) search method, and a formal Petri net structure is introduced to detect thetoken player assuring deadlock-free. In order to make the scheduling strategy generated by GA meetthe required constraint of deadlock-free, Petri net is involved to make the implementation of thejob scheduling in an FMS deadlock-free. The effectiveness and efficiency of the proposed approach isillustrated by using an example.

关键词： GA Petri net Deadlock-free scheduling

Tensile Mechanical Behavior of Cold Rolled Si-Mn Steel Under Different Strain Rates

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Journal of Iron and Steel Research International 2011年第S1期18卷 262-265页

作者： HE Yan-lin,LIN Yun-tao,HE Zhong-ping,ZHU Na-qiong,LI Lin (school of materials science and engineering,shanghai university,shanghai 200072,china) shanghai Univ Sch Mat Sci & Engn Shanghai 200072 Peoples R China

Tensile mechanical behavior of cold rolled Si-Mn steel after TRIP (TRansformation Induced Plasticity) and DP (Dual Phase) treatment were investigated under different strain *** dynamic tensile test was carried out using the rotation disk bar-bar tensile impact *** static tension test condition,the values of total elongation for TRIP steel was approximately 2-3 times higher than DP steel because of TRIP effect;the DP steel showed a higher tensile strength because of 39.6vol% martensite in the *** results of tension test at high strain rate condition were *** the studied steel,the elongation increased with increasing strain rate due to softening of matrix caused by adiabatic heating;in addition,TRIP steel at low strain rate was always higher than that at high strain rate because progressive strain induced retained austenite was suppressed at high strain rate.

关键词： cold rolled Si-Mn steel TRIP and DP treatment mechanical properties stain rate

Nucleation Mechanism for Bainite

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Journal of materials science & Technology 2002年第1期18卷 1-2页

作者： Xi ZHANG, Xuejun JIN and T.Y.Hsu(Xu Zuyao)school of materials science and engineering, shanghai Jiao Tong university, shanghai 200030, china [ Manuscript received October 8, 2001] shanghai Jiao Tong Univ Sch Mat Sci & Engn Shanghai 200030 Peoples R China

Based on the experimental results that solute-depleted zone was observed in Cu-28Zn-4AI (mass fraction) at 523 K, AG is calculated as a positive according to the thermodynamic criteria for the spinodal decomposition of a ternary systems. So, the solute-depleted zone cannot be formed by spinodal decomposition. Dislocation density required by the formation of solute-depleted zone is estimated greater than 7.89×109 cm-2, according to the segregation of solute atoms around dislocations, which is not consistent with the practical situation for the alloy at 523 K. Associated with the internal friction experimental fact that internal friction peaks appear within the incubation for bainitic transformation in Cu-Zn-AI alloy, the equilibrium temperature, TO, is evaluated as 433 K for solute-depleted Cu-25Zn-3.4AI, which is lower than the experimental temperature 523 K. Thus, nucleation by shear mechanism is impossible in this circumstance. Therefore, it is concluded that, like bainite in steels and Ag-Cd, bainite in Cu-Zn-AI alloys nucleates by diffusional mechanism, just implied by the experimental existence of solute-depleted zone.

关键词： Bainitic transformation Prebainitic phenomenon Solute-depleted zone Diffusion Nucleation

Effect of electrolytes on electrochemical properties of graphene sheet covered with polypyrrole thin layer

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Progress in Natural science:materials International 2011年第6期21卷 460-466页

作者： Ya-meng CAI~(1,2),Zong-yi QIN~1,Long CHEN~2 1.State Key Laboratory for Modification of Chemical Fibers and Polymer materials, Donghua university,shanghai 201620,china 2.College of Material science and engineering,Donghua university,shanghai 201620,china [a] State Key Laboratory for Modification of Chemical Fibers and Polymer materials Donghua University Shanghai 201620 China [b] College of Material science and engineering Donghua University Shanghai 201620 China

Graphene sheet(GS) was successfully covered with a polypyrrole(PPy) thin layer through in situ chemical oxidative polymerization of pyrrole monomers in aqueous solution by using GS as a support material and ferric trichloride as an *** resulting nanocomposite was studied by field emission scanning electron microscopy(FE-SEM),Fourier transform infrared spectroscopy(FT-IR) and electrical measurements,including cyclic voltammetry(CV),galvanostatic charge/discharge experiment (GCD),and impedance spectroscopy(EIS).It has been found that the nanocomposite exhibited a typically curved and layer-like structure,and conformational change of PPy chains occurred due to the n-n stacking interaction between the graphitic structures in GS and aromatic rings of the PPy *** attention was paid to the effect of electrolytes on electrochemical properties of the nanocomposites,as expected,electrochemical performance was dependent on the nature of the electrolyte,and the neutral electrolytes containing alkali metal ions were found to be very suitable for GS/PPy *** with the pure PPy,the nanocomposite possessed larger specific capacitance and lower internal impedance,indicating that the nanocomposite can be a promising candidate as electrode material for supercapacitors.

关键词： nanocomposites graphene polypyrrole electrochemical property electrolyte

Cellulose nanocrystals as green fillers to improve crystallization and hydrophilic property of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

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Progress in Natural science:materials International 2011年第6期21卷 478-484页

作者： Hou-yong YU~(1,2),Zong-yi QIN~1,Zhe ZHOU~2 1.State Key Laboratory for Modification of Chemical Fibers and Polymer materials, Donghua university,shanghai 201620,china 2.College of Material science and engineering,Donghua university,shanghai 201620,china [a] State Key Laboratory for Modification of Chemical Fibers and Polymer materials Donghua University Shanghai 201620 China [b] College of Material science and engineering Donghua University Shanghai 201620 China

The green nanocomposites of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV) with various cellulose nanocrystals (CNCs) contents were prepared by solution casting *** effects of CNCs on the crystallization behavior,spherulitic morphology,crystal structure and hydrophilic property of PHBV were studied by differential scanning calorimeter(DSC),polarized optical microscope(POM),wide-angle X-ray diffraction(WAXD) and static water contact angle *** is found that the CNCs act as an effective nucleation agent for crystallization of PHBV,inducing an increase in the melt crystallization temperature of the nanocomposites.A study of the non-isothermal crystallization kinetics further illustrated that overall crystallization rate of PHBV in the nanocomposites was faster than that of neat PHBV,but exhibited a decrease in the crystallinity and the spherulite size of PHBV. Furthermore,the contact angle decreased from 60.1°for neat PHBV to 32.5°for the nanocomposites with 10%CNCs(mass fraction).

关键词： nanocomposites poly(3-hydroxybutyrate-co-3-hydroxyvalerate) cellulose nanocrystals crystallization behavior hydrophilic property

Application of the Long-Chain Linear Polyester in Plastification of PVC

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Journal of Wuhan university of Technology(materials science) 2008年第1期23卷 100-104页

作者：李岩 school of materials science and engineering Tongji University

The plastification modification of poly （vinyl chloride）（PVC） with the long-chain linear polyester （LP） synthesized by linear dodecanedioic acid （DC12） or tetradecanedioic acid （DC14） with different diols is investigated. The processing characteristics, mechanical properties and extraction property of the PVC/LP blends in different solvents （xylene, cyclohexane, ethanol） were also studied in detail. All results were compared with that of the PVC plasticized with dioctyl phthalate （DOP）. The results show that the molecular weight, molecular structure and loading of LP greatly influence the mechanical properties of the PVC/LP blends. The processability and the mechanical properties of PVC plasticized by LP are comparable to those of the corresponding PVC/DOP blends. However, the PVC/LP blends posses much better migration resistance property than the corresponding PVC/DOP blends, which makes the long-chain linear polyester become a very good plasticizer candidate for PVC industry.

关键词： poly (vinyl chloride) long-chain linear polyester DOP plasticizer migration resistance

Underwater Digital Terrain Model with GPS-aided High-resolution Profile-scan Sonar Images

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Journal of shanghai jiaotong university(science) 2008年第2期13卷 233-238页

作者：周拥军寇新建 school of Naval Architecture Ocean and Civil EngineeringShanghai Jiaotong University

The whole procedures of underwater digital terrain model (DTM) were presented by building with the global positioning system (GPS) aided high-resolution profile-scan sonar *** algorithm regards the digital image scanned in a cycle as the raw *** the label rings are detected with the improved Hough transform (HT) method and followed by curve-fitting for accurate location;then the most probable window for each ping is detected with weighted neighborhood gray-level co-occurrence matrix;and finally the DTM is built by integrating the GPS data with sonar data for 3D *** case of an underwater trench for immersed tube road tunnel is illustrated.

关键词： digital terrain model high-resolution sonar Hough transform neighborhood gray-level co-occurrence matrix

An Improved Model Updating Method of Reduced-Models for Finite Element Model

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Journal of shanghai jiaotong university(science) 2010年第3期15卷 377-384页

作者：李伟明洪嘉振 school of Naval Architecture Ocean and Civil EngineeringShanghai Jiaotong University

Most of exiting model updating methods based on the substructure matrices did not consider the effect of model reduction process on model updating which led to the updating results could not become more and more accurate with the improvement of the model reduction precision and the convergence rate was greatly *** order to solve this problem,this paper analyses the basic reason about this problem,and proposes an improved model updating method of reduced-models,named as improved reduced cross-model cross-mode(IRCMCM) *** proposed method eliminates the disadvantageous effect by adding a correction term to the model updating formula and employing an iterative *** results obtained by the referenced method and IRCMCM method are compared by numerical examples of satellite's plates,which indicate the model updating results are more accurate by using the proposed method,and the model updating precision becomes better with the precision of the model reduction upgraded and the convergence rate is improved to a large extent at the same time.

关键词： finite element method model updating model reduction iteration

Virtual multi-dimensional internal bonds model and its application in simulation of rock mass

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science china(Technological sciences) 2008年第2期51卷 192-201页

作者： ZHANG ZhenNan1,2 & GE XiuRun3,4 1 Department of Civil engineering,shanghai university,shanghai 200072,china 2 shanghai Institute of Applied Mathematics and Mechanics,shanghai university,shanghai 200072, china 3 Institute of Geotechnical engineering,shanghai Jiao Tong university,shanghai 200030,china 4 Institute of Rock and Soil Mechanics,Chinese Academy of sciences,Wuhan 430071,china 1. Department of Civil engineering Shanghai University Shanghai 200072 China 2. shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China 3. Institute of Geotechnical engineering Shanghai Jiao Tong University Shanghai 200030 China 4. Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China

VMIB (virtual multi-dimensional internal bonds) is a multiscale mechanical model developed from the VIB (virtual internal bond) theory. In VIB theory,the solid mate-rial is considered to consist of random-distributed material particles in microscale. These particles are connected with normal bonds. The macro constitutive relation is derived from the cohesive law between particles. However,in VMIB,the micro particles are connected with both normal and shear bonds. The macro constitutive relation is derived in terms of bond stiffness coefficients. It has been theoretically certified that there exists a corresponding relationship between the two bond stiffness coefficients and the two macro material constants,i.e. the Young’s modulus and Poisson ratio. This corresponding relationship suggests that it should be necessary and sufficient to simultaneously account for the normal and shear interactions between particles. Due to the fact that the fracture criterion is directly incorporated into the constitutive relation,both VIB and VMIB present many advantages in simulating fractures of materials. In the damage model of rock mass,a damage tensor is usually defined to describe the distribution of cracks. The damage value in one direction determines the relative stiffness of rock mass in this direction. In VMIB solid,the relative distribution density of micro bonds in one direction determines the relative macro stiffness of the material in this direction. The effects of the damage value and the relative distribution density of bonds are consistent. To simulate the failure behavior of rock mass with VMIB,the presented paper sets up a quantitative relationship between the damage tensor and the rela-tive distribution density of bonds. Comparison of the theoretical and the experi-mental results shows that VMIB model can represent the effect of distributed cracks on rock mass with this relationship. The presented work provides a founda-tion for further simulating fracture behavior

关键词： VMIB (virtual multi-dimensional internal bonds) rock mass VIB (virtual internal bonds) multi-cracked body numerical simulation