Performance degradation simulation of electronic product for reliability analysis
To study analysis method of performance degradation during long term operation based on function simulation, accelerated degradation test was carried out on the power supply module directly, and the test data was used for reliability analysis. As the same time, accelerated degradation test was carried out on the key components in power supply circuit. The test data was injected into the functional simulation model of power supply to simulate performance degradation and analyze reliability. Finally the results of the two kinds of analysis were compared to demonstrate the effectiveness of the proposed simulation method. Comparison shows that average life span of power supply is 281560 hours based on accelerated degradation test while 357290 hours based on degradation simulation. Since only considering degradation of the key components, the result of simulation method is of partial optimism. But the deviation is in a reasonable range, which proved that the method is effective.
Reliability Assessment of Electronic Parts Based on Cumulative Degradation by SSADT
In order to assess the storage reliability of electronic parts of new ammunition quickly,the method of step-stress accelerated degradation testing(SSADT) was put forward.First the scheme of electronic parts by SSADT was expatiated.Then the basic hypothesis of reliability assessment of electronic parts based on cumulative degradation by SSADT was brought forward.The train of thought and method of the reliability assessment method was analyzed particularly.The method achieved storage reliability assessment of ammunition electronic parts under the condition of "zero failure".
Study on essential drug use status and its influencing factors among cerebral infarction inpatients in county level hospitals of Anhui Province, China
Background and purpose Drug costs is one of the main components of hospitalization expenditure for cerebral infarction inpatients. In China, the National Essential Medicine System (NEMS) was created to relieve the heavy drug-cost burden for patients. The objective of this study was to investigate essential drug-use status and its influencing factors among cerebral infarction inpatients in county-level hospitals of Anhui province, China. Methods Three county-level hospitals were selected through a multi-stage cluster random sampling method. The hospitalization cost data of cerebral infarction inpatients in the three hospitals were extracted from the Anhui provincial information platform of the New Rural Cooperative Insurance System (NCMS), and whether the proportion of essential drug cost in the total drug cost reached the median value of 33.05% which was set as the evaluation index for essential drug-use status. Questionnaires for hospitals and physicians were designed and given to them to assess influencing factors. Results We retrieved the cost data of 2,189 inpatients from the NCMS platform and investigated 51 corresponding physicians in total. The drug costs accounted for 52.6% of the total hospitalization cost, and essential drug costs alone accounted for 37.0% of the total drug costs. The essential drug-cost proportion was high among physicians with a higher recognition degree on NEMS, older age, lower final academic degree, longer work experience and lower professional title. Married physicians and those with tight organizational affiliation also prescribed more essential drugs. Conclusions Increasing the proportion of essential drugs was an effective way to reduce the disease burden for cerebral infarction patients. Perfecting the NEMS, increasing government investment, reinforcing education and propaganda, and formulating relevant incentive and restrictive mechanisms were all effective ways to promote and increase the number of essential drug prescriptions written by physicians.