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To develop coordination polymers (CPs) as catalysts to selectively catalyze the reaction of C-H bond activation of arylalkanes to their homologous ketones, three new Cu(I)-based coordination polymers (Cu-CPs) [CuI(aas-TPB)] (1), [CuBr(ass-TPB)CHCN] (2), and {[Cu(ass-TPB)]Cl} (3) (TPB = N,N,N-tris(3-pyridinyl)-1,3,5-benzenetricarboxamide) were synthesized. Structural variations from a herringbone fashion one-dimensional framework of 1 to a two-dimensional framework of 2 containing a 48-membered macrocycle and a cationic three-dimensional framework of 3 filled with Cl anions were observed arising from the different halogen ions (I, Br, and Cl). 1-3 were used as the green heterogeneous catalysts to catalyze direct C-H bond activation reactions of arylalkanes to ketones under mild reaction conditions with water as solvent. Handy product separation, convenient reaction procedures, and recyclability of these catalysts make the catalytic system fascinating. Moreover, the Cu-CPs performed the reaction with high regioselectivity due to the unique spatial confinement effect of CPs.

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Nanoparticles-laden gas film (NLGF) was formed by adding SiO2 nanoparticles with volume fraction in the range of 0.014–0.330% and size of 30 nm into the air gas film in a thrust bearing. An effective viscosity of the gas-solid two phase lubrication media was introduced. The pressure distribution in NLGF and the load capacity of the thrust bearing were calculated by using the gas-solid two phase flow model with the effective viscosity under the film thicknesses range of 15–60 μm condition. The results showed that the NLGF can increase the load capacity when the film thickness is larger than 30 μm. The mechanism of the enhancement effect of load capacity was attributed to the increase of the effective viscosity of the NLGF from the pure air film, and the novel lubrication media of the NLGF can be expected for the bearing industry application.

Purpose -The purpose of this paper is to study the load capacity of nanoparticles-laden gas film (NLGF) in thrust bearing. Design/methodology/approach -SiO 2 nanoparticles were added into gas to form an NLGF. The nanoparticles volume fraction in the film was controlled by a vibrator. The film thickness and the film pressure were measured by a micro cantilever displacement sensor and a membrane pressure sensor, respectively. The total load that makes the film thickness keeping constant was quantified, and then, the film load capacity was obtained. Findings -The investigation shows that nanoparticles can enlarge the film load capacity remarkably; even a little amount of nanoparticles (0.01 per cent) could lead to a sharp rise. With the increase of nanoparticles volume fraction, load capacity increases. However, the increment of load capacity decreases gradually. In addition, the film pressure variation proves the enhancement effect of nanoparticles on the film load capacity. Research limitations/implications -The paper is restricted to the findings based on NLGF, which is formed by dispersing SiO 2 nanoparticles in gas film as an additive. The experimental results are applicable within the range of nanoparticles volume fraction of 0.01-0.33 per cent. Originality/value -The fact that nanoparticles could enlarge the gas film load capacity is verified by experiment for the first time. This study reveals the corresponding relation between nanoparticles volume fraction and the film load capacity.