The aim of this study was to evaluate the effect of a porous tantalum rod implant for the treatment of early femoral head necrosis. From April 2007 to June 2009, a total of 35 femoral head necrosis patients (with 49 hips) were treated with core decompression in combination with the insertion of a porous tantalum rod. The mean age was 38.2 years (22-50 years) and the mean follow-up period was 15.2 months (12-36 months). The surgical time and blood loss were recorded. The Harris hip scores and radiological results were adopted for evaluation. The mean surgical time was 35 min, and the mean blood loss was 50 ml. The mean Harris score improved from 48.3 ± 3.2 preoperative to 83.7 ± 4.1 at the last follow-up (p < 0.05). Eight affected hips exhibited progressive pain including three hips that progressed to femoral collapse, and one revision followed by total hip arthroplasty (THA). For the patient who underwent revision and THA, the articular cartilage surface was seen to be damaged and fragmented. High-density metal particle residuals were observed on radiograph in the bone channel and femoral marrow cavity. We conclude that the selection criteria for porous tantalum implants should be early and intermediate stages of femoral head necrosis. Further study is warranted to reveal whether the metal particles released play a role in the progression of pain and failure.

A super-twisting sliding mode controller is proposed for nonlinear system with external disturbance in order to reduce chattering phenomenon. A criterion is obtained that guarantees the convergence of system states in finite time by Lyapunov stability method. Finally, the results of simulation for carbon fiber multilayer diagonal loom are presented to confirm the effectiveness of the super-twisting sliding mode controller design in agreement.

No abstract

No abstract

A numerical and experimental investigation about effects of cone plate upsetting on the plastic inclusion morphology in the center of forgings was carried out in this paper. The results show that radial dimension of inclusion zone after cone plate upsetting is 80% of the flat plate upsetting under the condition of thermal-mechanical model. However, the percentage is only 70% when cooling influence of anvils on the workpiece is ignored. The constant temperature model is acceptable by upsetting of heavy forgings. The radial deformation degree of inclusion in the center of forgings could be even smaller than average deformation degree of whole workpiece by cone plate upsetting of heave forgings if some measures of lubrication [1] [2] <1 m 20 90 [3] [4-5] [6] II. A. 45 φ6 978-1-4244-7739-5/10/$26.00 ©2010 IEEE