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This study's objective is an irrationally nonlinear oscillating system, whose bifurcations and consequent multi-stability under the circumstances of single potential well and double potential wells are investigated in detail to further reveal the mechanism of the transition of resonance and its utilization. First, static bifurcations of its nondimensional system are discussed. It is found that variations of two structural parameters can induce different numbers and natures of potential wells. Next, the cases of mono-potential wells and double wells are explored. The forms and stabilities of the resonant responses within each potential well and the inter-well resonant responses are discussed via different theoretical methods. The results show that the natural frequencies and trends of frequency responses in the cases of mono- and double-potential wells are totally different; as a result of the saddle-node bifurcations of resonant solutions, raising the excitation level or frequency can lead to the coexistence of bistable responses within each well and cause an inter-well periodic response. Moreover, in addition to verifying the accuracy of the theoretical prediction, numerical results considering the disturbance of initial conditions are presented to detect complicated dynamical behaviors such as jump between coexisting resonant responses, intra-well period-two responses and chaos. The results herein provide a theoretical foundation for designing and utilizing the multi-stable behaviors of irrationally nonlinear oscillators. [ABSTRACT FROM AUTHOR]

Based on the urban railway transportation vehicle wheel,three kinds of typical wheel plate（ straight plate,single S plate and double S plate） were set up. The study presents the calculation method of structure load and thermal load of the urban railway transportation vehicle wheel,and focuses on the thermal-mechanical coupling performance of the three types of wheel plate under different abrasion,the characteristic of the thermal-mechanical coupling stress is obtained under the thermal-mechanical coupling condition. The results show that three kinds of urban railway wheels are all satisfied with the requirements of fatigue strength; and the double S plate wheel has a better anti-fatigue performance than straight plate and single S plate wheel in the coupling field.

Abstract: Objective. : To compare the feasibility, morbidity, and survival outcome of the laparoscopic radical hysterectomy and pelvic lymphadenectomy (LRH+LPL) with abdominal radical hysterectomy and pelvic lymphadenectomy (ARH+APL) for FIGO stage Ib-IIa cervical carcinoma. Methods. : The consecutive cases with FIGO Ib-IIa cervical cancer from August 1998 to December 2005 were documented, including 90 patients underwent LRH+LPL, and 35 patients underwent ARH+APL as control group. The clinic data of perioperative periods and survival were compared between groups. Results. : In laparoscopy group the operating time increased significantly (262.99±67.6 min vs. 217.2±71.56 min, P =0.001), and the recovery time of bowel decreased significantly (1.96±0.62 days vs. 2.40±1.06 days, P =0.025). No significant difference was found between groups when the blood loss during operation (369.78±249.94 ml vs. 455.14±338.05 ml, P =0.125), numbers of the pelvic lymph nodes resected (21.28±8.39 vs. 18.77±9.47, P =0.151), recovery time of bladder function and postoperative hospital stays were compared. All laparoscopic procedures were completed successfully except 2 cases converted to laparotomy. The median follow-up was 26 months (range 5 to 84 months). Ten and five cases lost to follow-up in laparoscopy and laparotomy group, respectively. Excluding the lost cases, the recurrence rate (13.75% vs. 12%, P >0.05) and the mortality rate (10% vs. 8%, P >0.05) between groups was similar. Conclusion. : Our data demonstrated that cervical cancer could be treated successfully with LRH+LPL with similar efficacy and recurrence rates to ARH+APL. LRH+LPL is a safe and effective alternative to conventional abdominal surgery for stage Ib-IIa cervical cancer, and should be used if the surgeon is sufficiently trained. Its clinical value should be confirmed by multicenter randomized clinic trials. [Copyright &y& Elsevier]