The hysteresis, stick-slip, and rotational speed-dependent characteristics in a basic dual mass flywheel are obtained from a static and a dynamic experiments. Based on the experimental results, a nonlinear model of the transferred torque in this dual mass flywheel is developed, with the overlying form of nonlinear elastic torque and frictional torque. The nonlinearities of stiffness are investigated, deriving a nonlinear model to describe the rotational speed-dependent stiffness. In addition, Bouc-Wen model is used to model the hysteretic frictional torque. Thus, the nonlinear 2-degree-of-freedom system of this dual mass flywheel is set up. Then, the Levenberg-Marquardt method is adopted for the parameter estimation of the frictional torque. Finally, taking the nonlinear stiffness in this model into account, the parameters of BoucWen model are estimated based on the dynamic test data.

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The flowers, leaves, seed cakes and fruit shells of Camellia oleifera are rich in bioactive polysaccharides, which can be used as additives in food and other industries. In this study, a Box−Behnken design was used to optimize the extraction conditions of polysaccharides from C. oleifera flowers (P-CF), leaves (P-CL), seed cakes (P-CC), and fruit shells (P-CS). Under the optimized extraction conditions, the polysaccharide yields of the four polysaccharides were 9.32% ± 0.11 (P-CF), 7.57% ± 0.11 (P-CL), 8.69% ± 0.16 (P-CC), and 7.25% ± 0.07 (P-CS), respectively. Polysaccharides were mainly composed of mannose, rhamnose, galacturonic acid, glucose, galactose, and xylose, of which the molecular weights ranged from 3.31 kDa to 128.06 kDa. P-CC had a triple helix structure. The antioxidant activities of the four polysaccharides were determined by Fe2+ chelating and free radical scavenging abilities. The results showed that all polysaccharides had antioxidant effects. Among them, P-CF had the strongest antioxidant activity, of which the highest scavenging ability of DPPH•, ABTS•+, and hydroxyl radical could reach 84.19% ± 2.65, 94.8% ± 0.22, and 79.97% ± 3.04, respectively, and the best chelating ability of Fe2+ could reach 44.67% ± 1.04. Overall, polysaccharides extracted from different parts of C. oleifera showed a certain antioxidant effect, and could be developed as a new type of pure natural antioxidant for food.

AbStmet:On the basis of analyzing the characters of collision in distributed cooperation design process and summarizing collision species, the author studies collision-snlntion d e knowledge representative method, collision-solution case knowledge framework representative method and collision-solution case template mechanism in depth. By combining heuristic d e and case, the author put8 forward a collision-solution support tecbniqne by integrating case-based and de-based masoning. According to the theomticaJ research results, a collision-snlntion support tool has been developed based on relation database, the tool can help solving collision in the distributed moperation design procm 2. The characters and t y p of the collision in distributed cooperation design environment 2.1. The characters of collision By virtue of studying and analyzing the collision in cooperation design course, we find there are the characters of inevitability, variety and relevancy[l,6]. The types of collisionAccording to the object collision involved, the collision can he divided into design collision, process collision and resource collision[2,3]. Collision-solution on the hasis of integrating -based and rnle-based reasoningWh&n looking for collision-solution method, collisionsolution automation degree should not be emphasized excessively, the members of team can get collision-solution advice form collision-solution support tool. SO the important thing is to extend collision-soluPon knowledge by improving system stability in the process of system running for collision resolution. It will provide effective decision-making knowledge for designer negotiation collision. 0-7803-8403-2/04/$20.00 a 2 0 0 4 IEEE

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