政府投资项目工程变更的探讨与研究

结合工作实践总结,针对工程变更内容的复杂性、涉及造价变化大的特点,对政府投资项目工程变更的概念、产生的原因、类型、控制方法与措施、存在的难点进行探讨与研究,以期为实际工程提供参考。     

Method for Detecting Multi-modal Vibration Characteristics of Landmines

The acoustic vibration characteristics of landmines are investigated by means of modal analysis. According to the mechanical structure of landmines, a certain number of points are marked on the landmine shell to analyze its multi-modal vibration characteristics, based on laser self-mixing interferometer and taking 69 plastic landmine as an example, the vibration detection experiment system is built to show the results of analytical method of multi-modal testing. The first and second order natural frequencies of the bricks are 38 HZ and 106 HZ, 112HZ and 232HZ for plastic landmines, and 74HZ and 290HZ for metal landmines. The first and second order natural frequencies of the bricks are far smaller than those of plastic landmines and metal landmines. This indicates that landmines show multi-modal vibration characteristics under external excitation, which are significantly different from those of bricks. The findings can be used for further research on acoustic landmines detection technology.     

震击器动载荷有限元分析

卡钻事故在石油钻井工业中时有发生，计算震击动载荷的方法各不相同。结合现场实例，在合理假设的基础上，建立有限元分析模型，计算得出震击动载荷是上提拉力的3．3倍。该结果和现场实际非常接近，对震击器的使用有重要的指导价值。     

Combined static mixers for high viscous fluids mixing

A new static mixer Cross-over-Disc has been invented to strip off the boundary layer and to make strong radial mixing. The pressure drop of Cross-over-Disc is 12-26 times as large as that of empty pipe with equivalent diameter and length. The mixing performance of Cross-over-Disc with 14 elements has been investigated in the viscosity range of 190–250 Pa·s by decoloration method, and the gray analysis of images shows that mixing inhomogeneity is about 7.5% and 9.4% for the mixing ratio of 5:1 and 10:1, respectively. Furthermore, mixing inhomogeneity for a combination of static mixing elements (four from Cross-over-Disc and three pairs from Sulzer-type) can be decreased to 2.1%–3.1% within a reasonable range of pressure drop.     

三维CAD实验课程体系建设

随着先进设计和制造技术的推广应用,机械学科内涵发生了很大变化,传统的设计与绘图教学模式和手段已不适应现有的要求.介绍了机械类专业本科课程改革方案,提出基于三维的CAD实验课程体系建设,设置了一系列不同层次的CAD培训课程,教学内容和机械学科的课程设置相关联,循序渐进.通过课程学习,使学生建立基于三维的工程设计概念,培养工程素质和创新设计能力.     

气浮+BAF工艺用于污水处理回用的试验研究

采用气浮-BAF工艺对齐齐哈尔污水厂A+A/O工艺二级出水进行深度处理。当气水比为3∶1,回流比为2∶1时,气浮-BAF工艺有很好的有机物去除和脱氮效果;在保证脱氮效果的情况下,投加35 mg/L PAC,出水TP小于0.5 mg/L。结果表明,气浮-BAF工艺出水水质符合回用标准。     

P-Ⅲ中Φ值数学解法的探讨

本文从Φ值的数学意义着手 ,采用数学计算的方法进行求解 ,方便了计算机程序的编制 ,提高了计算的精度和速度。是对P -Ⅲ中Φ值求解的有益的尝试和探讨。     

转台自动控制仪设计

为了实现转台控制的自动化,需在上位机和转台之间设计接收上位机指令、输出相应脉宽调制信号的控制设备,基于这类需求设计本控制仪。就转台自动控制仪的系统设计及工作原理做了详细介绍,通过对基于单片机控制技术和光电编解码技术、滤波等的控制系统设计,实现了对转台正反转及启停控制、角度脉冲信号采集和向上位机反馈角度数据的自动化,较之原有手动控制方式,在准确性、工作效率等方面均有大幅度的提高,具有现实应用价值。     

中央空调冷凝热的热回收方案探讨

针对中央空调系统产生的大量低品位冷凝热,提出了两种利用冷凝热回收制备生活热水的方案,对它们各自的特点、局限及控制原理做了较为详尽的阐述,并对我国冷凝热回收发展做了展望。