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In this study, a modeling method for investigating the dynamic characteristics of a hydraulically driven shell manipulator with revolute clearance joints is presented. This model accounts for the effect of the clearance, the flexibility of the rotating beam, and the coupled dynamic characteristics of the hydraulic cylinder. A modified contact force model was developed to simulate the physical properties of realistic revolute joints with small clearances, heavy loads, and variable contact stiffnesses and damping coefficients with variations of the indentations. Considering the strong coupling relationship between the hydraulic cylinder and the flexible beam, a system equation of motion combining the state variables of the hydraulic cylinder and mechanical system was established. The complex nonlinear friction force of the hydraulic cylinder motion was constructed using a modified LuGre model, and the parameters of the friction model were identified using intelligent identification algorithms. Moreover, a test system for the shell manipulator was established to achieve experimental validation. Finally, the effects of the clearance size and the stiffness of the cylinder support on the dynamic response were investigated.

Abstract: Ammonium perchlorate(AP) and LiBH4 can form an oxidation‐fuel energetic system, which provides a new development direction in designing novel mixed explosive formula. The microcalorimetry and self‐designed slow cook‐off setup were used to study thermal performance of AP/LiBH4 energetic powders and grains respectively. Experimental results show that heat release in microcalorimetry method for the mixed system at low temperature was due to the reaction between LiBH4 and residual water vapour. The oxidant gases from AP decomposition participate in the oxidation of LiBH4 at high temperature. The ignition temperature for the AP/LiBH4 grain was 270 °C and the explosion reactions were violent in slow cook‐off test. [ABSTRACT FROM AUTHOR]

Objective: To investigate the understanding of the nurses of different levels concerning Total Quality Control (TQC)., Methods: A total of 198 nurses using stratified random sampling in proportion to the ratio of different levels of the nurses. A questionnaire with approved validity was used in the survey, and the results were statistically analyzed., Results: In terms of basic knowledge of TQC, the scores of assistant nurses the lowest (P<0.05), and the responsible nurses had lower scores than head nurses and nursing officers (P<0.05), while the scores of the nurses whose length of service ranged from 3 to 10 years were lower than those of nurses who had been in service for above 10 years. In terms of TQC common methods, both assistant nurses and responsibility nurses had lower scores than nurses-in-charge, head nurses and nursing officers (P<0.05). The scores of nurses in service for less than 15 years did not significantly differ, but were obviously lower than those of nurses in service for over 15 years. There was no significant difference between the scores of nurses with different academic degrees., Conclusion: The TQC knowledge of the nurses are different based on their working levels and length of service.