Nonlinear Simulation of Rotor Dynamics Coupled with Journal and Thrust Bearing Dynamics under Nonlinear Suspension

This study performs a dynamic analysis of a rotor supported by an oil-film journal and thrust bearings. The analysis of the rotor-bearing system is investigated under the assumptions of an incompressible lubricant, a flexible rotor, and negligible side leakage in the thrust bearing. The numerical results show that the nonlinear dynamics of the system vary with the nondimensional speed ratio and the initial value of the displacements in the horizontal, vertical, and axial directions. Specifically, some routes of periodic responses, subharmonic motions into chaos, out of chaos to subharmonic responses, or suddenly into chaos, suddenly out of chaos to periodic ones were found.     

仲丁基丙二酸的制备及其热解研究

以丙二酸二乙酯和2-溴代丁烷为原料合成了仲丁基丙二酸,并进行了1HNMR1、3CNMR、LC/MS/MS、热重和差示扫描量热分析,以及在卷烟中的热解试验。结果表明:合成的物质为目标产物仲丁基丙二酸;仲丁基丙二酸在空气中和卷烟中热解均释放出β-甲基戊酸。     

2,3,4,6-葡萄糖四异戊酸酯的合成及其在卷烟中的应用

以乙二胺的醋酸盐作皂化剂,由1,2,3,4,6-葡萄糖五异戊酸酯合成了2,3,4,6-葡萄糖四异戊酸酯,用1HNMR、高分辨质谱、硅烷化衍生质谱进行了表征,并进行了卷烟加香试验。评吸结果表明,合成的葡萄糖四异戊酸酯能赋予混合型卷烟烟气以异戊酸的特征香气。