TANDEM双丝焊在造船拼板焊接中的应用

介绍了TANDEM双丝焊在造船拼板焊接中的原理、应用、工艺结果表明,TANDEM焊接工艺对组对时预留间隙、母材种类的适应性较强,热输入低,变形小,减少焊后处理成本,焊接效率高、焊接速度快.TANDEM焊接工艺是船厂拼板焊接比较理想的焊接工艺.     

Effects of temperature and blank holding force on biaxial forming behavior of aluminum sheet alloys

Biaxial forming behavior is investigated for three aluminum sheet alloys (Al 5182 containing 1% Mn (5182+Mn), Al 5754, and 6111-T4) using a heated die and punch in the warm forming temperature range of 200–350 °C. It is found that, while all three alloys exhibit significant improvement in their formability compared with that at room temperature, the non-heat-treatable alloys 5182 + Mn and 5754 give higher part depths than that of heat-treatable 6111-T4. The formability generally increases with decreasing BHP (BHP), but increasing the forming temperature and/or BHP minimizes the wrinkling tendency and improves the forming performance. The stretchability of the sheet alloys increase with increasing temperature and increasing BHP. For the alloys and forming conditions involved in the current study, the formability, measured in terms of part depth, comes mainly from the drawing of metal into the die cavity, although stretching effects do influence the overall forming behavior. The optimum formability is achieved by setting the die temperature 50 °C higher than the punch temperature to enhance the drawing component. Setting the die temperature higher than the punch temperature also improves the strain distribution in a part in such a manner that postpones necking and fracture by altering the location of greatest thinning.     

利用微波介电加热和微波干燥水解法制备TiO2微粒

利用微波介电加热和微波干燥条件下TiCl4直接水解的方法制备出平均尺寸为40m，粒径分布窄，均为球形且形态均一，团聚较少，金红石型的TiO2纳米粒子，其内部品粒平均大小为17nm。而传统加热和干燥条件下形成的纳米微粒平均为60nm，粒经大小不均一，形态较不规则，团聚严重。微波加热和干燥方法具有清洁、快速均匀高效、环境友好的优点，推广前景良好。TiCl4水解法经济便利，适于工业化生产。     

关于煤炭硫分分级的探讨

根据国家质量技术监督局的计划安排,国家标准GB／T15224－1994《煤炭质量分级》需要修订。本文主要讨论“煤炭硫分分级”方面的内容。     

喷雾型地板上光蜡的研制

喷雾型地板上光蜡也称乳剂型地板上光蜡，是蜡和乳化剂在加热搅拌条件下进行乳化反应而生成的水乳状液蜡上光剂，生产工艺简单，稳定性和上光效果较好，本文对新型光蜡的典型配方和影响乳液稳定性，上光效果的诸因素进行研究，找出配制稳定剂乳液及提高上光效果的最佳工艺条件。     

酚醛泡沫及其夹芯板材开发进展

综述了酚醛泡沫及其夹芯板材的国内外进展,包括应用开发和市场现状,参考文献9篇。同时简单介绍了酚醛泡沫的生产工艺及其市场需求和效益。     

自控温加热带的研制

研究了炭黑含量、辐照剂量以及体系共结晶性对以高密度聚乙烯/乙烯 丙烯酸乙烯酯共聚物为基材的自控温加热带电阻率及电热稳定性能的影响,以及加工条件和后处理工艺对材料电性能的影响。结果表明,50～80kGy的辐照剂量为本体系提供优异的电热稳定性,适当的加工及后处理工艺能大大改善该体系的导电性。     

6m大容积焦炉烘炉实践与体会

介绍了 6 m大容积焦炉由冷态到转入正常加热温度的烘炉操作过程中 ,按照一定的升温曲线 ,通过对焦炉热工和炉体膨胀的科学管理 ,确保新建焦炉顺利由冷态过渡到生产状态。     

某砖混结构加层改造的设计

通过对某砖混结构加层改造的设计实践,介绍了加层改造的方法,分析了在加层改造过程中需解决的问题。主要包括地基及基础的处理,墙体抗压、抗震验算,节点连接处理,如何保证新结构与原结构连接的整体性,楼梯间处理,构造柱的连接等,并提出了结构加层对施工技术的要求。给出一些具体的构造大样,供工程设计参考。     

Time dependences of conduction and self‐heating in acetylene carbon black‐filled high‐density polyethylene composites

The time dependences of electrical conduction and self‐heating behaviors in high‐density polyethylene filled with acetylene carbon black of 0.082 in volume fraction are studied in relation to voltage and ambient temperature. The characteristic decay current constant τ_i, and the exponential growth time constant for self‐heating τ_g are determined for the samples under voltages U above the critical value U_c for the onset of self‐heating. The influences of voltage and ambient temperature on τ_i and τ_g as well as the amplitude of the low‐resistance to high‐resistance switching are discussed on the basis of the random resistor network (RRN) model and the relationship between U_c and the intrinsic resistivity. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1124–1131, 2006