Abstract.A reversible addition-fragmentation chain transfer (RAFT) agent with carbazole as Z-group was immobilized on the surfaces of the cross-linked poly (4-vinylbenzyl chloride-co-styrene) (PVBCS) nanospheres with a diameter of about 70 nm by the reaction of benzyl chloride groups in the PVBCS between carbazole and carbon sulfide. Then surface RAFT polymerization of 4-vinylpyridine (4VP) was used to modify the nanospheres to produce a well-defined and covalently tethered P4VP shell. By surface activation in a PdCl2 solution and then reduction by hydrazine hydrate (N2H4·H2O), the P4VP composite shells were obtained containing densely palladium metal nanoparticles. The chemical composition of the nanosphere surfaces at various stages of the surface modification was characterized by X-ray photoelectron spectroscopy (XPS). Transmission electron microscopy (TEM) was used to characterize the morphology of the hybrid nanospheres. The Pd/P4VP shell nanospheres were also applied to the catalytic reaction and proved to be efficient and reusable for the Heck reaction.

Aiming at the fabrication of a micro-textured surface, a novel piezoelectric-driven non-resonant elliptical vibrator is proposed in this paper; the output characteristics could be adjusted by the length change of the tool holder. The flexible mechanism is the primary structure of the vibrator, which includes a lever type mechanism, an enhanced Scott–Russell mechanism, and a T-shaped mechanism. The former two mechanisms are used to enlarge the output of the piezoelectric actuator, and the T-shaped mechanism is applied to transfer the parallel movements to the elliptical trajectory. The theoretical models including the elliptical trajectory, output stiffness, and resonant frequencies are established to investigate the impacts of the tool holder and controlling signals on the output characteristics of the vibrator, which are further validated using the finite element analysis method. A prototype is developed by integrating the non-resonant elliptical vibrator assembly and controlling system. Some experiments are carried out to verify the basic performance and the adjustable properties of the vibrator.