Poly(isocyanidcs), ( R N = C < ) n, can be prepared from isocyanidcs, R N += C " , by the catalytic action of nickel(II) compounds. The main chain of these polymers is a rigid helix. This helical conformation results from a restricted rotation around the single bonds that connect the main-chain carbon atoms. Polymerization of achiral isocyanides generally gives a racemic mixture of leftand righ...

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The thermal behaviors of the ball screw feed system significantly affect machining accuracy machine tool, which is widely valued by users and manufacturers. In current screws error models, moving heat source at nuts simplified to a fixed simplify calculation, can decrease model’s prediction accuracy. A novel modeling method for proposed this paper based on FEM. method, nut loaded into model cha...

Figure 1. The bionic prosthesis’ mass of 2.0 kg is equivalent to a biological foot and partial shank of an 80 kg person. The prosthesis includes a carbonfiber in-series leaf spring, unidirectional parallel leaf spring, and heel and forefoot leaf springs that provide elasticity. A series-elastic actuator performs negative and positive work. The actuator is comprised of a 200-Watt DC brushless mo...