Nonlinear behavior of disk spring with complex contact state.

Disk springs are widely used as preload and isolation due to their unique mechanical properties. In the prior research, the effect of linear friction on the disk spring was considered, but contact stiffness, another nonlinear contact factor, is ignored. Accordingly, in this paper, the asymmetric displacements of the contact edges are first derived, and the accurate friction dissipations are obtained, as a way to evaluate the effect of friction on the system.

Dynamic characteristics analysis of planetary gear system with internal and external excitation under turbulent wind load.

According to the working characteristics of a 1.5 MW wind turbine planetary gear system under complex and random wind load, a two-parameter Weibull distribution model is used to describe the distribution of random wind speed, and the time-varying load caused by random wind speed is obtained. The nonlinear dynamic model of planetary gear transmission system is established by using the lumped parameter method, and the relative relations among various components are derived by using Lagrange method.

Anti-oxidative stress effect of loading-dose rosuvastatin prior to percutaneous coronary intervention in patients with acute coronary syndrome: a prospective randomized controlled clinical trial.

Background And Objectives: Administration of a loading dose of a statin (HMG-CoA reductase inhibitor) prior to percutaneous coronary intervention (PCI) contributes to protection from myocardial ischemic-reperfusion injury. This trial was designed to investigate the effect and mechanism of loading-dose rosuvastatin therapy before PCI in patients with acute coronary syndrome.

Methods: One hundred and forty-three patients with acute coronary syndrome were randomized to either the loading-dose (rosuvastatin 40 mg given 4 h before PCI) or conventional-dose (rosuvastatin 10 mg given 4 h before PCI) group.