CM04斜锲调节机构中螺旋传动副的受力分析

宝钢冷轧厂CM04平整机组斜锲调节机构中螺旋传动副实行了国产化，分析了国产化后的螺旋传动副的受力情况，并进行了较核计算。     

轧机传动机构改造小结

通过对轧机主传动系统的改造，论述了在传动机构的设计中，首先应考虑的是在满足生产要求的前提下，尽力简化传动机构，从而提高机械效率，降低设备故障停机时间，提高经济效益。     

齿轮传动失效分析

文章分析了选矿厂主要使用的齿轮的现状,对制造齿轮的材料、齿轮的加工精度、齿轮的失效形式以及产生的原因、发生的后果进行详细的剖析,结合具体情况并对如何减轻失效的频率提出一定的防护措施。     

平炉吊挂自锁装置设计原理

本文介绍了炼钢厂平炉吊挂自锁装置的设计原理。这一装置在炼钢平炉采用后，对提高平炉炉令起到积极作用。     

南钢15t转炉改造主传动机构设计

1 前言 南京钢铁厂转炉炼钢车间始建于1969年,现有半悬挂式15t氧气顶吹转炉3座,原设计年生产能力70万t,为全省转炉炼钢之最。由于该车间建成投产时间较长,设备陈旧,     

短应力线立辊轧机主传动齿轮机构分析

本文简要分析了ＧＹＬ型短应力线立辊轧机主传动齿轮机构的结构形式，齿轮机构中的曲线齿锥齿轮的齿制，中硬齿面和硬齿面齿轮的材料、热处理和制造方法等问题。     

850轧机压上闸自锁装置改造

８５０轧机是轨梁厂的成品机架，它的运转是否产量正常直接影响着我厂的生产和产品质量。通过对８５０轧机压上闸自锁装置的发行可以杜绝跑闸现象，减少质量事故提高产品质量。     

螺纹吊杆断裂失效分析

为寻找螺纹吊杆断裂原因,使用扫描电镜和金相显微镜对试样进行分析.结果表明,该螺纹吊杆断裂属疲劳断裂,是组织未经调质处理和表面机加工粗糙等多种因素综合所致.     

40Cr螺栓断裂原因分析

采用光电直读光谱仪、光学显微镜和扫描电子显微镜对材质为40Cr的螺栓断裂试样进行了宏观和微观形貌及化学成分分析。结果表明,该螺栓断裂为应力疲劳断裂,导致断裂的主要原因是其表面脱碳以及螺栓的松动。     

Performances and failure mechanism of semi-metallic friction materials doping rare earths

In order to improve performance of semi-metallic friction material,the specimens doped with rare earth(cerous nitrate) were prepared.The effects of rare earth(cerous nitrate) and post heat treatment on properties of friction materials were discussed,and failure mechanism of friction materials was also analyzed.The result showed that the existing of cerous nitrate could stabilize friction coefficient,lower wear rate and increase impact strength,and when the content of the cerous nitrate was 3.0 wt.%,the semi-metallic friction material possessed optimal performances.The different post heat treatments had an influence on the friction coefficient,wear rate and linear thermal expansion coefficient of semi-metallic friction material.The worn surface and fractured surface were observed and analyzed by scanning electronic microscopy(SEM).It was identified that the semi-metallic friction materials doped with cerous nitrate acted abrasive wear and adhesive wear at the low temperature,and abrasive wear,adhesive wear and fatigue wear of materials appeared at the high temperature.The fracture of materials might be the result of matrix cracking interacting with interface separation.     

Analysis of black-streak defects on food-container screw caps

The cause of black-streak defects on food-container screw caps is analyzed by two-dimensional gas chromatography time-of-flight mass spectrometry,morphological analysis,and energy-dispersive X-ray spectroscopy.An immersion experiment was conducted with the cap immersed in different concentrations of acetic acid to simulate the growth of black streaks.The experimental results show that the acetic acid concentration in food is closely related to the appearance of the black-streak defects.Acetic acid is speculated to permeate into the gaps of the cap,followed by the formation of ferric acetate(light brown solid).The ferric acetate then breaks through the paint surface and its color coincides with that of the paint,which leads to the formation of the black-streak defects.     

厚钢板焊接热影响区失效机理分析及改善方法研究

分析了厚钢板大线能量焊接后热影响区(HAZ)的失效机理,介绍了利用微细夹杂物改善HAZ性能的研究情况.粗晶热影响区脆化是由于晶粒粗大及不良组织而引起,粗大的奥氏体晶粒是焊接热影响区韧性恶化的主要原因.抑制焊接HAZ晶粒长大是改善厚钢板可焊性的关键因素.用真空感应炉分别冶炼了不同成分的钢,研究Mg对低碳钢HAZ性能的影响.结果表明含Mg钢HAZ的低温韧性较比不含Mg钢有较大幅度提高.通过激光高温显微镜原位观察发现,含Mg钢在1400℃保温300 s后奥氏体晶粒仍然保持着细小的结构,这主要归功于Mg添加后生成的细小粒子所产生的钉扎作用,该发现为改善厚板HAZ韧性提供了一种方法.     

40Cr螺杆断裂分析

材质为40Cr的螺杆在热处理后沿轴心方向出现开裂。为了查明断裂原因,用光电直读光谱仪、光学显微镜及显微硬度仪对螺杆断裂处进行了化学成分、宏观、微观以及显微硬度分析。研究结果表明:螺杆的化学成分符合产品的技术要求,螺杆断裂是由于螺杆在淬火前存在较严重的宏观的中心偏析和微观的条带状偏析,以及淬火冷却时生成了较多的块、半网状铁素体等组织缺陷,引起螺杆的力学性能下降,导致螺杆沿轴心方向断裂。     

Analysis of anticholinesterase-induced neuromuscular transmission failure

To define the underlying mechanism of neuromuscular transmission failure induced by anticholinesterases, we simultaneously performed surface recordings of compound muscle action potentials (CMAPs) and intracellular recordings of miniature end-plate potentials (MEPPs), miniature end-plate current (MEPCs), and end-plate potential (EPPs) in rat diaphragms exposed in vitro to 1 x 10(-4) to 2 x 10(-2) mmol/L neostigmine methylsulfate. At low concentrations of neostigmine, repetitive stimulation of the phrenic nerve resulted in decrement followed by complete recuperation of CMAP amplitudes. This bimodal pattern was associated with maximal end-plate depolarization at the beginning of the stimulation period, increased MEPP amplitudes, and prolonged time constants of MEPC decays. Higher concentrations of neostigmine resulted in a unimodal decline of amplitudes of CMAPs and EPPS, reduced MEPP amplitudes, and a double exponential time course of MEPC decays. These results indicate that low concentrations of anticholinesterases impaired neuromuscular transmission by producing transient depolarization of the end-plate region. Higher concentrations induced desensitization and direct blockade of the end-plate receptor channel, probably in its open conformation.     

变频器在千吨料仓螺旋运输机上的应用

介绍了变频器在干吨料仓螺旋运输机上的应用情况及效果；指出了改造中的注意事项。     

轧机液压压下系统恒压变量泵动态特征分析

压下系统供油泵的动态特征直接关系到系统工作性能,从而对产品质量造成影响。通过导出该泵的动态特性,分析了供油压力波动和管路振动的原因,并用于指导实践,通过更新改造,解决了现场难题。     

炭/炭复合材料的摩擦学性能与摩擦磨损机理的研究现状

综合评述了C/C复合材料摩擦磨损性能的各项影响因素及摩擦机理的研究现状,指出C/C复合材料摩擦磨损研究存在的问题,并提出了在进一步研究中值得重点关注的课题。