工艺参数对杯形内啮合齿轮旋压成形影响的数值模拟研究

基于金属塑性变形原理和旋压工艺的特点,提出了杯形薄壁内啮合齿轮旋压成形技术,建立了齿轮旋压三维弹塑性有限元模型并进行了数值模拟,分析了齿轮旋压成形时各变形区不同方向应变分布和金属流动规律,定性分析了主要工艺参数对齿轮旋压成形的影响规律。结果表明,压下量对齿轮成形起关键作用,并对齿根减薄影响大于齿顶增厚的影响,进给比对齿轮成形影响不大,大的旋轮圆角半径有利于齿顶增厚。     

Natural frequency of tapered high pier considering pile-soil interaction

In seismic design of tapered high pier, the analysis of natural vibration frequency is of great importance. According to the engineering features of tapered high pier in mountainous area, a vibration calculation model was set up considering the tapered pier characteristics and pile-soil interaction. Based on Southwell frequency composition theory, it consists of elastic deformation of bridge pier and the rigid deformation of group piles, which are respectively solved by the finite-element method and energy method, and then the natural frequency is derived. The comparison between the measured and calculated results shows that the calculation errors with and without considering pile-soil interaction are 4.9% and 14.7%, respectively. Additionally, the main parameters (pier height, section variation coefficient and lateral foundation horizontal proportional coefficient) affecting natural frequency were investigated. The result shows that natural frequency ascends with the increase of the lateral foundation horizontal proportional coefficient; and it is quite necessary to consider the pile-soil interaction in natural frequency calculation of tapered high pier.     

联枯/次磷酸铝/MHB对聚丙烯的阻燃作用

通过极限氧指数(LOI)测定、垂直燃烧试验和锥形量热分析研究了联枯/次磷酸铝/三聚氰胺氢溴酸盐复合物(DMDPB/ALHP/MHB)对聚丙烯(PP)的阻燃作用。结果表明,DMDPB/ALHP/MHB对PP具有良好的阻燃协效作用,当DMDPB,ALHP和MHB的质量分数分别为0.250%,1.000%和1.500%时,阻燃均聚PP(PPH)的LOI可达到25.8%,垂直燃烧级别达到V-2;当它们的质量分数分别为0.250%,2.500%和2.500%时,阻燃共聚PP(PPB)的LOI可达到23.4%,垂直燃烧级别达到V-2。添加ALHP/MHB明显降低了PP的最高热释放速率、热释放总量,复合DMDPB使以上参数进一步降低。     

无压烧结Al2O3/Si3N4纳米复合陶瓷的力学性能

对Al2O3／Si3N4体系进行无压烧结。获得试样相对密度大于98％，物相分析烧结体中并没有Si3N4颗粒存在而是形成SIALON相。Si3N4和Al2O3反应生成的β-SIALON相颗粒不仅分布在Al2O3晶粒晶界处也存在于Al2O3晶粒内部，形成独特的“内晶型”结构。当受到外力时既能诱发穿晶断裂，又能引起裂纹偏转，从而起到增强的作用。由于产生晶界滑移，韧性有所下降。     

Vibration compaction characteristics of rock filling embankment

The dynamic model experiment of the rock filling embankment was carried out to investigate the vibration compaction mechanism. The rock filling materials were compacted by the plate-vibrated compactor, and the characteristics of the rock filling materials, such as settlement, pressure change and response waveform, were measured by the dynamic earth pressure gauge and accelerometer. Moreover, a new method for detecting the compactness of the rock filling embankment was proposed based on the maximum dry density and modulus of deformation. The results show that the process of vibration compaction includes compact, elastic deformation and loose stages, and the vibratory pressure transfers to the surroundings from the vibration center in non-linear rule. Furthermore, the test results obtained by the present method are basically in agreement with those obtained by the traditional method, and the maximum relative error between them is about 0.5%.     

旋压技术分类及应用

通过对旋压的工艺特点、成形原理和发展应用的研究,从不同角度对旋压技术进行新的分类,有助于从本质上掌握旋压成形工艺,促进对各种旋压方法的理论分析和实验研究、并为更多的新工艺新方法的产生提供科学依据。     

加氢裂化变压器油提质探索及工业应用

中国石油化工股份有限公司金陵分公司加氢裂化装置运行至末期,产品变压器油中多环芳烃含量增加且颜色较深,造成销售困难;本文介绍了利用NJBMZDA-II催化剂针对加氢裂化变压器油开展的产品提质试验情况,结果表明在反应温度150℃、空速为3.0 h~(-1)、压力为3.0 MPa、氢油体积比500∶1的条件下,原料中总芳烃含量降低了13%,其中稠环芳烃含量降低为0.6%,产品赛氏比色提高了7个单位;利用公司尾油异构化装置工业应用情况表明,在空速2.68 h~(-1)、反应温度178℃、反应压力2.95 MPa、氢油体积比305∶1工况下,变压器油稠环芳烃含量、油品色泽等指标都能达到产品指标。     

沈阳旧住宅小区改造中节能技术的应用

通过对沈阳地区既有住宅小区现状的分析，结合旧房改造中建筑节能技术的应用，探讨如何通过相应技术手段，满足市民改善人居环境的需求，推进建筑节能技术在小区改造中的应用。     

《九华云栖谷》

作品说明:本案从自然得到灵感与启示,采用悬挑架空、叠落搭接、多样灵活的方式建造可持续、健康、环保和具有多样性的有机建筑,秉承少即是多的原则,建造极简建筑。借用《桃花源记》的方式形容建造的场景:树欲静而风不止,波澜起,枝影婆娑,沿九曲青砖小径,穿行竹林间,隐约可见竹屋错落浮于竹叶间。转身忽见一泓池泉,水雾缭绕。清逸空灵,不染纤尘。人、建筑、景致相融共生,远离喧嚣,避世而居。     

高氯原油加工情况总结

2013年5月多个石化企业连续发生管输油氯含量严重超标事件,导致部分换热设备结垢,从而造成装置停工.对近两年某石化企业加工高氯原油情况进行了总结,有机氯主要集中在204 ～ 260℃馏分段,原油中总有机氯质量分数高达40 μg/g.加工高氯原油时发现:常减压装置装置压力升高及设备结盐;Ⅱ套汽油加氢装置反应系统压差较高;Ⅲ套柴油加氢装置结盐严重;Ⅱ套柴油加氢装置结盐及设备腐蚀等.逐步完善优化高氯原油加工方案,并对以上问题采取了处理措施:严格控制氯离子质量分数不大于10 μg/g;尽量将结盐点控制在第3台高压换热器后;严格控制高温不锈钢段的注水次数与注水时间;建议装置停工前48 h切换为不含氯原油,降低加工高氯原油对全厂影响程度.