Maintenance optimization of periodic replacement for mono-unit production system is a widely discussed topic.In practice,the replacement for a parallel production system with multi-unit served by one repairman is univ...Maintenance optimization of periodic replacement for mono-unit production system is a widely discussed topic.In practice,the replacement for a parallel production system with multi-unit served by one repairman is universal.The replacement action is often implemented in a maintenance window at random,although the replacement period appears as a quasi-periodic event.To optimize these maintenance policies,this study analyzes a bivariate quasi-periodic replacement policy (T,W) for a two-unit parallel production system with a maintenance window and one repairman.One unit of the system is replaced when either a failure occurs or a replacement plan comes in the maintenance window,whichever comes first.If one of the two units is in the replacement,the other may continue operating or waiting until the replacement is completed.An optimal replacement window [T*,T* + W*] can be obtained by jointly considering the system's long-running cost rate and the availability using the genetic algorithm.This study also introduces three examples of the production system with different types of units to illustrate the proposed policy.展开更多
为探究不同反应条件对MOFs微观结构和宏观性能的影响,在不同反应条件下,以硫酸铜(CuSO_(4)·5H_(2)O)和6-(吡啶-3′-基)间苯二甲酸(H_(2)L)为材料,制备了2种金属有机框架材料(MOFs){[Cu_(2)(L)_(2)·C _(2) H _(3) N]}n(1)和{[C...为探究不同反应条件对MOFs微观结构和宏观性能的影响,在不同反应条件下,以硫酸铜(CuSO_(4)·5H_(2)O)和6-(吡啶-3′-基)间苯二甲酸(H_(2)L)为材料,制备了2种金属有机框架材料(MOFs){[Cu_(2)(L)_(2)·C _(2) H _(3) N]}n(1)和{[Cu(HL)_(2)]}n(2),并对合成的金属有机框架材料1和2进行了结构分析、TGA和FTIR表征以及对染料的吸附性能研究。单晶衍射数据分析表明:配合物1和2都属单斜晶系,P 21/c空间群。配合物1是一种基于双核轮桨次级构筑单元[Cu_(2)(COO)_(4)]构筑的三维紧密堆积化合物,配合物2由于配体部分质子化,结构中存在氢键[O_(3)—H…O_(4)],将二维层状网络结构连接成三维结构。配合物1是rtl拓扑类型的网络结构,拓扑符号为(42.610.83);配合物2是sql拓扑类型的网络结构,拓扑符号为(4^(4).6^(2))。2种配合物在相同时间间隔下对不同染料降解性能表明配合物2对水溶液中的孔雀石绿具有一定的化学吸附降解能力。展开更多
基金the National Natural Science Foundation of China(No.71561016)the China Postdoctoral Science Foundation(Nos.2017M613297XB , 2019T120964)。
文摘Maintenance optimization of periodic replacement for mono-unit production system is a widely discussed topic.In practice,the replacement for a parallel production system with multi-unit served by one repairman is universal.The replacement action is often implemented in a maintenance window at random,although the replacement period appears as a quasi-periodic event.To optimize these maintenance policies,this study analyzes a bivariate quasi-periodic replacement policy (T,W) for a two-unit parallel production system with a maintenance window and one repairman.One unit of the system is replaced when either a failure occurs or a replacement plan comes in the maintenance window,whichever comes first.If one of the two units is in the replacement,the other may continue operating or waiting until the replacement is completed.An optimal replacement window [T*,T* + W*] can be obtained by jointly considering the system's long-running cost rate and the availability using the genetic algorithm.This study also introduces three examples of the production system with different types of units to illustrate the proposed policy.
