To investigate the aging behavior of fluoroelastomer FM-1D in hot air,with compression set as a parameter for seal aging,aging tests were conducted on fluoroelastomer FM-1D under different initial compression rates in a hot air environment ranging from 60℃to 150℃.The aging kinetic equation relating compression set of FM-1D to temperature and time was established,in order to predict its aging life at 25℃.The test results indicated that when the initial compression rate was 30%,the compression set exhibited an Arrhenius relationship with both test temperature and time.However,at a initial compression rate of 50%,the compression set gradually conformed to the Arrhenius relationship as time extended.These findings provide a reference for determining accelerated testing methods and maintenance cycles for FM-1D rubber materials.

To evaluate the aging life of silicone rubber sealing materials in the electrolytic water environment,the compression permanent distortion was taken as the performance change parameter of the sealing ring.Three typical silicone rubber materials,G146,G199,and 6144,were subjected to aging tests in the electrolytic water.The aging data was analyzed by the Arrhenius equation.And the aging kinetics equation of permanent compression deformation retention rate and temperature time was established,the aging life of silicone rubber sealing materials at 25℃was predicted.The results indicate the aging life of G146,G199,and 6144,was 21.3 a,9.8 a,and 12.0 a respectively.These prediction results provide a reference for determining the maintenance cycle of the sealing material.

Objective To evaluate a normative and systematic training mode for teachers of community general practice.Methods A total of 16 general practice teachers,who came from Fenglin community health service centre in Shanghai,participated three-stage training mode during March 2011 to February 2012.The clinical competence evaluation and questionnaire survey were conducted before and after training.Fifty trainees trained by the teachers also received clinical competence evaluation.Results After the three-stage training,the test score in medical knowledge,physical examination and clinical skills of the teachers did not change significantly (P =0.794,0.674 and 0.326).The self assessment questionnaire survey of general practice teachers indicated a significant increase,especially in practice capability (t =-2.840,P =0.015) and overall quality (t =-3.017,P =0.011).After training by the teachers,the medical knowledge (t =-9.200,P =0.000),physical examination (t =-9.947,P =0.000) and clinical skills (t =-14.828,P =0.000) of 50 trainees increased markedly.Conclusions Differed from conventional training courses,the three-stage training enhances teaching ability and overall quality of community general practice teachers,and provides a effective training model.