基于OOCPN结线分析和反向推理的城市轨道交通牵引供电系统故障诊断方法

基于面向对象的思想和有色Petri网理论,构建库所的令牌,描述城市轨道交通牵引供电系统中组成结点的元件、开关及结点的含源性质,进而建立城市轨道交通牵引供电系统结线分析的OOCPN(Object-Ori-ented Colored Petri-Nets)模型。求解该模型可确定城市轨道交通牵引供电系统的故障域;然后结合专家经验以及牵引变电所综合自动化系统轮询到的保护动作信息,通过反向推理遍历搜索该故障域,对故障元件进行定位;根据专家推理规则以及城市轨道交通牵引变电所内的保护配合关系,判断开关的拒动行为。以城市轨道交通牵引供电系统馈线短路且馈线开关拒动为例进行验证,结果表明:提出的城市轨道交通牵引供电系统故障诊断方法能够实现对故障元件的准确定位和开关拒动行为的判断。

PREDICTION OF HYDRODYNAMIC PERFORMANCE OF THE FLAP RUDDER

In this paper a new method for predicting the hydrodynamic performance of the flap rudder behind a propeller was presented. The hydrodynamics of the rudder was calculated by the panel method and the performance of the propeller was predicted by the simplified propeller theory. The interaction between the rudder and propeller was determined by iterative procedure. The pressure distribution on rudder surface and the hydrodynamic performance of the flap rudder were discussed in the paper.

An Efficient and Practical Synthesis of Dibenzo[d,f][1,3]- dioxepines from 2,2＇-Dihydroxybiphenyl with Terminal Alkynes Catalyzed by Lewis Acid TiCl4

A synthetic strategy toward the cyclic addition of 2,2＇-dihydroxybiphenyl to terminal alkynes has been developed using Lewis acid TICl4 as catalyst. The reactions generated dibenzo[d,f][1,3]dioxepines derivatives in good yields with excellent regio-selectivity in the presence of catalytic amount of TICl4 under mild reaction conditions.