Delay Restoration of Single-Track Railway Rescheduling

On the basis of analysis of the principle of delay restoration in a disturbed schedule, a heuristic algorithm for rescheduling trains is developed by restoring the total delay of the disturbed schedule. A discrete event topologic model is derived from the original undisturbed train diagram and a back propagation analysis method is used to label the maximum buffer time of each point in the model. In order to analyze the principle of delay restoration, the concept of critical delay is developed from the labeled maximum buffer time. The critical delay is the critical point of successful delay restoration. All the disturbed trains are classified into the strong-delayed trains and the weak-delayed trains by the criterion of the critical delay. Only the latter, in which actual delay is less than its critical delay, can be adjusted to a normal running state during time horizon considered. The heuristic algorithm is used to restore all the disturbed trains according to their critical details. The cores of the algorithm are the iterative repair technique and two repair methods for the two kinds of trains. The algorithm searches iteratively the space of possible conflicts caused by disturbed trains using an earfiest-delay-first heuristics and always attempts to repair the earliest constraint violation. The algorithm adjusts the weak-delayed trains directly back to the normal running state using the buffer time of the original train diagram. For the strong-delayed trains,the algorithm uses an utility function with some weighted attributes to determine the dynamic priority of the trains, and resolves the conflict according to the calculated dynamic priority. In the end, the experimental results show that the algorithm produces ＂good enough＂ schedules effectively and efficiently in disturbed situations.     

值得注意的大型集装箱船参数横摇现象

本文介绍了大型集装箱船的参数横摇现象，对大型集装箱船的影响、参数横摇的成因和如何避免参数横摇的办法作了探讨，还介绍了一种实用的IPRP系统(INTERING PARAMETRIC ROLLPRE-VENTION)即英特灵参数横摇预防系统的英文字母首字的缩写。IPRP系统能使横摇运动减少20％左右。最后作者介绍了IPRP在3200TEU集装箱船上的应用情况和5500，IEU超巴拿马型集装箱船的耐波性试验的情况，图4、表4。     

圆梁山隧道PDK354+255～PDK354+275溶洞体施工技术

圆梁山隧道是渝怀铁路上最长的隧道 ,该隧道穿越高压富水区 ,施工难度极大 ,曾被称为“国内隧道设计、施工禁区工程”。系统介绍该隧道PDK3 54+ 2 55～DK3 54+ 2 75溶洞段的地质超前预测预报、超前注浆加固及支护、注浆效果的检查评定及施工过程 ,为今后类似工程的设计、施工提供借鉴依据     

新一代先进船用燃气轮机WR-21

Rolls-Royce公司耗资的4.8亿美元，历时超过8年，开发了新一代中冷-回热式复杂循环燃气轮机WR-21。作者认为它是目前世界最先进的船用燃气轮机。     

移相调压型开关电源的谐振换流技术

介绍了一种应用移相、谐振零电压换流ＰＷＭ控制技术的高频开关电源的研制，给出了重要参数的计算公式及相应的电压电流波形。实践证明，这种开关电源可以有效地减小开关损耗，提高效率。     

具有宽电压调节范围的谐振型变流器

针对传统的变流器中输出电压一般总是低于交流输入电压的状况，提出了一种新型串联谐振直流环节变流器。该变流器在取消直流大电感，并为开关器件提供零电流开关条件的同时，还可以实现变流器输出电压在交流输入电压以上或以下的较宽范围内任意调节，而不受输入电压大小的限制。介绍了电路的工作原理，给出了升压及降压时两组有代表性的试验波形。