Phase separation time/temperature dependence of thermoplastics-modified thermosetting systems

The cure-induced phase separation processes of various thermoplastics(TP)-modified thermosetting systems which show upper critical solution temperature (UCST) or lower critical solution temperature (LCST) were studied with emphasis on the temperature dependency of the phase separation time and its potential application in the cure time-temperature processing window. We found that the phase separation time/temperature relationship follows the simple Arrhenius equation. The cure-induced phase separation activation energy E _a(ps) generated from the linear fitting of the Arrhenius equation is irrelevant to the detection means of phase separation time. We also found that E _a(ps) is insensitive to TP content, TP molecular weight and curing rate, but it changes with the cure reaction kinetics and the chemical environment of the systems. With the established phase separation time-temperature dependence relation, we can easily establish the whole cure time-temperature transformation (TTT) diagram with morphology information which is a useful map for the TP/TS composites processing industry. __________ Translated from Acta Polymerica Sinica (China), 2007, (8): 725–730 [译自: 高分子学报]     

基于BP神经元网络优化电火花加工参数

基于BP神经网络模型对用电极(铜Cu)-材料(模具钢NAK80)电火花加工系统的一组参数进行了优化.计算结果表明,减少输入层神经元的数量可以加快收敛速度,但计算精度将受到影响.若保持隐层结构,仅由不同训练函数的学习结果改变权系数(映射)实现网络结构优化,则可能较好地预言加工效果.     

新型聚乙烯醇缩糠醛树脂的制备和性能研究

以聚乙烯醇(PVA)和糠醛(Fu)为主要原料,在酸性介质中通过羟醛缩合反应制得了聚乙烯醇缩糠醛,然后采用氮丙啶交联剂对聚乙烯醇缩糠醛进行改性,并对改性前后聚乙烯醇缩糠醛胶膜的力学性能、动态力学性能、热失重、耐水性和耐腐蚀性等进行了对比试验。研究结果表明,改性后聚乙烯醇缩糠醛胶膜的拉伸强度提高了29.12%,断裂伸长率提高了33.23%,储能模量由11659.25MPa增加到12750.3MPa,玻璃化转变温度提高了3℃左右,并且耐水性和耐腐蚀性都有所提高。     

抽油机减载器在中原油田的应用

本文介绍了中原油田的一种新型采油配套工具——抽油机减载器,并对其结构特点、工作原理、主要技术参数、使用要求、现场应用等进行了详细介绍。该减载器应用两个不等径活塞（一个为φ44mm,另一个为φ70mm）上下受力的不同,由这个压力差所产生的力作用于减载器减载活塞的下端面,使其产生一个向上的举升力,从而达到了减轻抽油机驴头载荷之目的;该减载器充分利用液压原理,达到减轻杆柱、驴头载荷,设计原理新颖,矿场应用表明其可明显改善深抽效果。     

聚酰胺-6黑芯切片的产生原因及预防

从聚合管的内件设计及由温度和真空所引起的聚合管液位波动等方面详细讨论了黑芯切片和凝胶物产生的原因.并通过前后聚的工艺控制模式、工艺条件的改变以及对工艺路线的改进等方面探讨了预防黑芯切片和凝胶物的产生.     

亚微米LiCu0.1Mn1.9O3.9F0.1电极活性材料的合成与性能

采用溶胶-凝胶法制备了F-和Cu2 复合掺杂的LiCu0.1Mn1.9O3.9F0.1锂离子电池正极材料.XRD和SEM表征表明合成产物具有良好的尖晶石结构,样品粒度为亚微米级,且分布均匀;电化学性能测试结果表明,掺杂后样品的电化学阻抗较小,首次放电容量达112mA·h/g,充放电循环50次后,容量保持率为89.1%,电极材料具有较好结构稳定性和电化学性能.同时还探讨了LiCu0.1Mn1.9O3.9F0.1的合成及掺杂机理.     

生物质催化裂解制合成气的研究

以锯屑为原料,使用自制的镍基催化剂,在固定床装置上进行了催化裂解实验,并对裂解产物及其成分进行了分析.结果表明:随着温度的升高,焦油和焦炭产率减少,产气量明显升高,同时气体中CO和H2含量增加;和同温度下热解相比,镍基催化剂显著地促进了焦油的深度裂解,且有效地提高了产品气的品质.     

压力容器圆筒体上大开孔补强问题的探讨

容器上开孔后,必须充分考虑开孔补强问题。介绍了等面积法和压力面积法两种开孔补强方法关于开孔补强的异同,并就其中的一些问题进行了探讨。相比之下,ASME VIII-1附录1-7的计算方法是基于弹性设计准则,其安全裕度与GB150-1998基本相当,因此采用ASME的计算方法可以保证更为安全可靠。     

Influence of heat treatment conditions on bending characteristics of 6063 aluminum alloy sheets

Bending deformation behaviors of solution treated (ST), natural aged (NA) and T6 tempered 6063 aluminum alloy sheets were studied by three-point bending tests. The changes of bending force, interior angle, bending radius and sheet thickness in the fillet region were analyzed by experimental measurements and numerical simulations. The results showed that the bending characteristics were strongly dependent on the heat treatment conditions. The T6 alloy sheets were bent more sharply and local plastic deformation occurred severely in the fillet region. However, the ST and NA alloy sheets exhibited relatively uniform bending deformation and large bending radius. The bending force of T6 alloy was the highest, followed by the NA alloy and that of the ST alloy was minimum. After unloading, as compared with the ST and NA alloys, the springback of T6 alloys was markedly larger. The aging time showed a positive sensitivity on the springback and non-uniform bending deformability. The bending characteristics are attributed to the combined effects of yield strength, yield ratio and coefficient of neutral layer.     

内腔体密封槽堆焊技术研究

针对零件工作的特殊要求,分析了材质的焊接性,制定了合理的焊接工艺,运用堆焊技术不仅解决密封封槽的修复问题,满足了使用要求,而且为深孔加工提供了精确、可行的解决方法。