Equivalent magnitude-dependent discomfort under vertical vibration up to 100 Hz.

The effect of vibration magnitude on frequency-dependence of discomfort of human body is always overlooked with respect to the comfort equivalence contours, particularly for high-magnitude vibration in wideband frequency. In this study, the magnitude effect of vertical vibration on discomfort of human body is investigated experimentally. Nineteen male subjects are involved in the jury test of vibration discomfort in the vertical direction with 2-5 m/s2 in magnitude up to 100 Hz. It is shown that the growth rate of discomfort may exceed 1 due to the high-magnitude vibration employed. In this condition that the rate varies around 1, the Stevens' power law is not capable to properly represent the relationship between the subjective discomfort and the vibration magnitude. It means the equivalent comfort contours are not only dependent on the frequency range but also related to the vibration magnitude. Frequency weightings of vibration discomfort are influenced by the excitation magnitude. Practitioner summary: The occupant comfort to vertical whole-body vibration is affected by vibration magnitude. This study provides the effect of vibration magnitude on frequency-dependence of discomfort to whole-body vibration. It is suggested to propose variable frequency weightings for vibration discomfort evaluation under different magnitudes to achieve better comfort design.

Effect of piston texture at inclination and eccentricity work conditions on damping characteristics of a hydraulic shock absorber.

In order to accurately predict the damping characteristics of a hydraulic shock absorber under piston inclination and eccentricity conditions, especially, considering effects of piston surface construction. In present work, taking account of piston slight inclination and eccentricity, a more detailed mathematical model was developed to estimate effects of piston texture on damping characteristics. Based on the mathematical models of reservoir and compression stroke coupled with Reynolds equation, a new damping force model was developed, which analyzed effects of piston structure on damping characteristics. The mathematical models of piston texture, piston slight inclination, piston eccentricity and combinations of three cases are developed to analyzed in detailed effects of piston texture at different work conditions on damping characteristics. The results shown that the friction force of piston increases parabolically with increasing depth ratio, and that of piston increases linearly with increasing area ratio. Piston textures have little effects on damping characteristics at specific structural parameters conditions when piston normal operation, however, textures of slight inclined and eccentric piston have great effects. As a result, piston textures might cause high damping force, destroyed comfort and safety. Therefore, it is necessary that effects of piston surface construction were precisely predicted on damping characteristics under different work conditions. The results might provide a new insight for the design of hydraulic shock absorber and investigation of vehicle system dynamics.

Synthesis, insecticidal activities and structure-activity relationship study of dual chiral sulfilimines.

To investigate the "methyl" impact on bioactivity of sulfiliminyl dicarboxamides, a total of 16 novel N-cyano and N-trifluoroacetyl sulfiliminyl dicarboxamides containing m-heptafluoroisopropylated aromatic amino moiety were studied. Two series of sulfiliminyl substituents were designed, synthesized and evaluated against oriental armyworm (Pseudaletia separata Walker) for their insecticidal activities. Their chemical structures were established by corresponding [Formula: see text] NMR, HRMS and optical polarimetry. Bioassay results revealed that some of the title compounds showed potent insecticidal activities against oriental armyworm. Notably, compounds IIa, IIIa, IVa exhibited 100% activity at [Formula: see text], in particular, IIa showed a comparable control efficacy to that of the commercial product flubendiamide. The SAR of these N-cyano sulfiliminyl isomers can be summarized as follows (Sc, Ss) [Formula: see text] (Sc, Rs), while the N-trifluoroacetyl sulfiliminyl isomers is (Sc, Rs) [Formula: see text] (Sc, Ss). Comparative molecular field analysis indicated that an electropositive substituent, [Formula: see text] group in the benzene ring was very important for the improvement in biological activity. These results could hold promise for novel chiral sulfiliminyl RyR regulators.

Research on Controllable Degradation of Novel Sulfonylurea Herbicides in Acidic and Alkaline Soils.

The degradation issue of sulfonylurea (SU) has become one of the biggest challenges that hamper the development and application of this class of herbicides, especially in the alkaline soils of northern China. On the basis of the previous discovery that some substituents on the fifth position of the benzene ring in Chlorsulfuron could hasten its degradation rate, apparently in acidic soil, this work on Metsulfuron-methyl showed more convincing results. Two novel compounds (I-1 and I-2) were designed and synthesized, and they still retained potent herbicidal activity in tests against both dicotyledons and monocotyledons. The half-lives of degradation (DT50) assay revealed that I-1 showed an accelerated degradation rate in acidic soil (pH 5.59). Moreover, we delighted to find that the degradation rate of I-1 was 9-10-fold faster than that of Metsulfuron-methyl and Chlorsulfuron when in alkaline soil (pH 8.46), which has more practical value. This research suggests that a modified structure that has potent herbicidal activity as well as accelerated degradation rate could be realized and this approach may provide a way to improve the residue problem of SUs in farmlands with alkaline soil.