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Aiming at the detection of oil shock absorber abnormal noise, the test mode of the piston rod acceleration, and test data difference of elastic or rigid clamp for outer performance, for different clamping mode the shock absorber's outer performance test was carried out. By designing the contrast experiment of conventional fixture for outer performance test (called the rigid clamping) and the fixture for the piston rod acceleration test (called elastic clamping) , the structural and functional characteristics of conventional fixture and the fixture of the piston rod acceleration test was analyzed, then the reasons for the differences of outer performance curves by different fixtures were investigated, further more based on the working principle and structure parameters of shock absorber, the damping force model was established and simulated correctly. The results indicate that the two clamping modes are common in testing outer performance of damper, and also reflect the performance of the internal shock absorber in different way. [ABSTRACT FROM AUTHOR]

Abstract: A series of Ru–Zn catalysts with different Zn contents were prepared by co-precipitation. The catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) – Ar+ sputter, transmission electron micrographs (TEM)–energy dispersion scanning (EDS) and temperature-programmed reduction (TPR). The performances of the catalysts for benzene selective hydrogenation to cyclohexene were investigated in the presence of 0.6mol/L of ZnSO4. The results showed that the Ru and Zn in Ru–Zn catalyst were in metallic Ru and ZnO respectively and the ZnO was rich on the surface. The ZnO alone could not improve the selectivity to cyclohexene of Ru–Zn catalyst. However, the ZnO on the surface could react with ZnSO4 to form a (Zn(OH)2)3(ZnSO4)(H2O)5 salt. The (Zn(OH)2)3(ZnSO4)(H2O)5 salt chemisorbed played a key role in improving the selectivity to cyclohexene of Ru–Zn catalysts. After Ru–Zn(8.6%) catalyst was pretreated 22h in ZnSO4 solution at 140°C and 5MPa H2, a cyclohexene selectivity of 81.4% at a benzene conversion of 54.0% was achieved at 10min and a maximum cyclohexene yield of 58.9% was reached. Moreover, the activity was stable above 50% and the cyclohexene selectivity and yield were steadily above 76% and 40% on this catalyst in the first six recycles, respectively. [Copyright &y& Elsevier]