排序方式: 共有87条查询结果,搜索用时 93 毫秒
81.
82.
83.
A review of multi-component maintenance models with economic dependence 总被引:11,自引:0,他引:11
Dekker Rommert Wildeman Ralph E. van der Duyn Schouten Frank A. 《Mathematical Methods of Operations Research》1997,45(3):411-435
In this paper we review the literature on multi-component maintenance models with economic dependence. The emphasis is on papers that appeared after 1991, but there is an overlap with Section 2 of the most recent review paper by Cho and Parlar (1991). We distinguish between stationary models, where a long-term stable situation is assumed, and dynamic models, which can take information into account that becomes available only on the short term. Within the stationary models we choose a classification scheme that is primarily based on the various options of grouping maintenance activities: grouping either corrective or preventive maintenance, or combining preventive-maintenance actions with corrective actions. As such, this classification links up with the possibilities for grouped maintenance activities that exist in practice. 相似文献
84.
电接触热过程有限元模型在精密机电元件中的应用 总被引:2,自引:0,他引:2
李坚石 《高校应用数学学报(A辑)》1995,(1):113-124
本文论述了轻电可分合接触热过程有限元模型的构造,系统论述了精密机电元件电接触热过程计算模型的构造方法,并给出了小电流继电器中的一个应用实例。 相似文献
85.
介绍了常见签字笔的分类,并综述了近十年中签字笔油墨成分检测方法的研究进展,包括光谱法(拉曼光谱法、红外光谱法、显微分光光度法、紫外-可见导数光谱法),色谱法(薄层色谱法、气相色谱-质谱法、高效液相色谱法、高效毛细管电泳法、裂解气相色谱法)和综合分析法等(引用文献19篇)。 相似文献
86.
Bainye F. AngouaPatrick R. Cantwell Eric A. Stach Elliott B. Slamovich 《Solid State Ionics》2011,203(1):62-68
La0.6Sr0.4Co0.2Fe0.8O3 − δ-Ce0.8Gd0.2O1.9 (LSCF-CGO) thin films obtained by spray pyrolysis of a single precursor solution were investigated by XRD, TEM and impedance spectroscopy at annealing temperatures ranging from 500 to 900 °C. Films annealed at 600 °C contained a mixture of amorphous regions and crystalline regions composed of fine crystallites (< 5 nm). Annealing above 600 °C increased the ratio of crystalline to amorphous material, led to the segregation of the films into distinct LSCF and CGO phases, and promoted grain growth. The electrical behavior of the films depended on annealing temperature. At testing temperatures of 400 °C and below, the polarization resistance of films with lower annealing temperatures was larger than the polarization resistance of films with higher annealing temperatures. However, at testing temperatures of 500 °C and above the polarization resistance of films with lower annealing temperatures was equal to or lower than the polarization resistance of films with higher annealing temperatures. This was reflected by the activation energy that decreased with increasing annealing temperature. The varying electrical behavior may be related to microstructural changes that caused bulk diffusion to be the rate-limiting step in films with lower annealing temperatures and oxygen dissociation to be the rate-limiting step in films with higher annealing temperatures. 相似文献
87.