一种基于振动数据的旋转机械运行状态评价方法的探讨

旋转机械在工作时容易产生振动,一旦振动异常将严重影响到旋转机械的安全运行,因此振动是评价旋转机械运行状态的重要参数.通过反映旋转机械运行状态的振动特性指标,能对当前振动状态进行识别和评估.通常需要多个指标方能从不同的角度比较完整地反映旋转机械的运行状态,但直接从多个指标中直观地评估旋转机械的运行状态比较困难.该文尝试用一种基于振动数据的评价方法对旋转机械的运行状态进行评估,并通过实验室数据来验证这种方法.结果表明,该方法结论具有较高的可靠性,在工程上易于掌握.     

电机传感器对浸入式泵机械故障监测的实验研究

研究电机在作为激励器完成所需机械输出时,对液压泵站中电机所驱动的浸入式泵机械故障的感知能力,实现现场远程无损监测和诊断.利用电机输出端的电流和电压信号计算出激励器传感器特征参数,并给出了基于统计分析概率密度函数的在线自动监测算法.同时采集了振动信号进行对比分析.实验表明,本文所提出的电机传感器方法可以有效检测出驱动系统中的机械故障.     

工况模态分析理论的概念、应用和发展

简述了近十余年来的工况模态分析理论的概念、应用与发展,提出了今后进一步的研究和发展方向.     

A Study of Modification of M2 Cast High Speed Steel

M2 cast high speed steel was inoculated by addition of rare earth(RE)‐Al‐N, network eutectic carbides were eliminated, matrix structures were refined and the segregation of tungsten and molybdenum elements were relieved. In the condition that the hardness did not decrease, impact toughness obviously increased. Quenching at 1180 °C and three‐times tempering at 560 °C, the hardness of M2 cast high speed steel kept 65~66HRC, impact toughness reached 21.3J/cm². Modified M2 cast high speed steel had excellent thermal fatigue resistance and high temperature wear resistance. Roll made in modified M2 cast high speed steel had excellent service effect using in slit rolling mill stand of hot rolling bar mill.     

卫星数据站接入以太网的方法分析

针对电力系统内部作为应急通信手段的卫星数据通信系统,提出了一种将其与现有的广域网相结合,提高系统利用率的一种方法。     

Grain refinement of low carbon steel produced by CSP process

In comparison with conventional production for hot strips, compact strip production (CSP) brings about some new micro-structural phenomena. Investigations were carried out to clarify the grain refinement mechanism of low carbon steel strips produced by the EAF-CSP process. Samples, obtained from the same rolling stock during continuous rolling, were examined through SEM,TEM and XEDS. Thin slabs have a dominant columnar structure and the spacing of the secondary dendrite arms ranges from 90 to ～125 μm. The average grain sizes for the central area of the samples from the 1st to 6th pass are 41.6, 25.2, 21.4, 20.2, 13.1, 6.7 μm,respectively. Large number of nanometer oxide and sulfide have been found in the low carbon steel produced by the CSP process.The grain refinement mechanism can be summarized as follows: finer solidification structure of the thin slab; austenite recrystalliza-tion at higher temperature and stain accumulation at lower temperature caused by the great reduction of single rolling pass during continuous rolling; nano-scaled precipitates of sulfide and oxide which drag grain boundaries of austenite or ferrite to prevent the grain coarsening.     

Effects of heat treatment on structures and properties of high speed steel rolls

The effects of quenching temperature, cooling pattern, temper temperature and temper times on the structure and properties of high speed steel (HSS) rolls have been investigated. The results show that, when the quenching temperature is lower than 1050℃ the hardness of HSS increases with the quenching temperature increasing in oil cooling, but when the quenching temperature exceeds 1100℃ the hardness decreases. In the conditions of salt bath cooling and air cooling, the effect of quenching temperature on the hardness is similar to the above law, but the quenching temperature obtaining the highest hardness is higher than that in oil cooling. When the temper temperature below 350℃ the hardness of HSS has a little change, when above 475℃ the hardness will increase with the temper temperature increasing, and the highest hardness is obtained at 525℃. When the temper temperature continues to increase, the hardness decreases. Twice temper has little effect on the hardness, but three times temper decreases the hardness. HSS in air cooling has lower hardenability, oil cooling can easily produce crackle, and HSS quenching in salt bath has high hardenability and excellent wear resistance.     

苯乙烯在三氯化铁/联吡啶/1-溴乙基苯催化体系中聚合

用三氯化铁-2,2'-联吡啶-1-嗅乙基苯催化聚合苯乙烯,研究了聚合反应条件对聚合的影响,三氯化铁/2,2'-联吡啶/1-溴乙基苯摩尔比对聚合的影响,用凝胶渗透色谱研究了分子量和分子量分布。     

基于模糊AHP法的企业CIO静态优选模型

企业CIO甄选是一个包含定量因素和定性因素相结合的决策问题。根据企业信息主管的工作特点和工作职能,提出了基于企业信息化水平的CIO素质评价指标体系,并将层次分析法和模糊数学相结合,构建了企业CIO的静态优选模型。该模型对各指标进行层次加权,克服了传统模糊评价方法中指标过多时权重难以确定的问题,使企业CIO的甄选决策更为精确。最后,给出了一个算例。