铜绿假单胞菌popN^-突变子Ⅲ型分泌水平及与蛋白酶关系的研究

铜绿假单胞菌(Pseudomonas aeruginosa)Ⅲ型分泌系统(typeⅢsecretion system,TTSS)是重要的细菌致病因子之一,能够将酶蛋白直接注入到宿主细胞内,导致细胞损害的发生。重点研究了TTSS中的popN基因的功能,通过构建popN-突变子,发现该突变子在非诱导条件下,能够分泌酶蛋白,显示popN基因编码的蛋白对TTSS蛋白的分泌具有负调控作用。进一步研究发现,popN-突变子在不同培养基中TTSS的分泌水平存在着显著差异,影响对popN基因的功能的判断。为了解决这一矛盾,从几个方面分析了造成表型差异的可能因素,确定蛋白酶对TTSS分泌蛋白的降解作用,是表型差异存在的主要原因,从而首次系统地阐明popN-突变子在不同培养基中都具有TTSS组成型表达的表型,对于深入研究TTSS的调控机制具有重要意义。

基于模糊综合层次评判法的精密齿轮制造工艺优化优先度分析

传统故障模式影响及危害度分析(FMECA)多应用于产品故障模式风险分析,而未涉及产品制造流程工艺参数优化优先度分析,且其风险优先数(RPN)分析无法对严酷度、发生概率和检测难易程度进行权重分配。因而参照传统FMECA中的RPN分析方法,以精密齿轮制造工艺流程为研究对象,并考虑齿轮制造当前工艺水平和工艺改进成本等因素,提出优化优先数分析法从而代替RPN分析法,并结合层次分析法-模糊综合评判的方法对齿轮制造流程的各个工艺参数进行优化优先等级评判并排序。最终根据评判结果,提出对重要工艺参数改进的方案,从而提升精密齿轮产品的可靠性和保障性水平。

Improved design of online fault diagnoser for partially observed Petri nets with generalized mutual exclusion constraints

This paper investigates the fault detection problem for discrete event systems (DESs) which can be modeled by partially observed Petri nets (POPNs). To overcome the problem of low diagnosability in the POPN online fault diagnoser in current use, an improved online fault diagnosis algorithm that integrates generalized mutual exclusion constraints (GMECs) and integer linear programming (ILP) is proposed. Assume that the POPN structure and its initial markings are known, and the faults are modeled as unobservable transitions. First, the event sequence is observed and recorded. GMEC is used for elementary diagnosis of the system behavior, then the ILP problem of POPN is solved for further diagnosis. Finally, an example of a real DES to test the new fault diagnoser is analyzed. The proposed algorithm increases the diagnosability of the DES remarkably, and the effectiveness of the new algorithm integrating GMEC and ILP is verified.