Formation and investigation of epoxy intumescent compositions modified by active additives

Results are reported of research on intumescent composites based on epoxy resin cross‐linked with polyethylene polyamine and containing ammonium polyphosphate and such modifying additives as calcium borate, manganese dioxide, nickel, and chromium, containing tubulenes as gas‐formers and carbonization stimulators. The changes in composition and physicochemical properties of modified compositions under conditions of heat and fire were investigated by X‐ray photo‐electron spectroscopy, atomic force microscopy, and local force spectroscopy. Ammonium polyphosphate mainly stimulates carbonization processes on the inner surface of a bubble being formed during foam coke formation. The introduction of metal‐containing tubulenes leads to the formation of fire‐retardant and low flammability‐compositions with high coke and carbon structures content. The use of calcium borate in the compositions considerably increases the strength of foam coke being formed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1477–1483, 2002     

施加复合电磁搅拌对A357合金微观组织的影响

在半固态加工技术中，电磁搅拌是最早应用于制备非枝晶浆料的方法之一，同时也是半固态触变压铸技术最早获得工业应用的重要技术基础之一。采用自行开发的电磁搅拌器，研究了多种不同电磁搅拌方式在不同工艺条件下，单独施加或复合施加对A357合金微观组织的影响。试验结果表明：单一施加旋转感应电磁搅拌时，浆料径向组织很不均匀；单一施加无芯感应电磁搅拌。当搅拌电流较小时，径向组织也不均匀，增大电流，浆料质量有明显改善；采用（旋转感应＋无芯感应）复合电磁场进行复合电磁搅拌时，可在电流较小时获得满意的浆料质量。     

小孔矩形腔体屏蔽特性的研究

本文提出了有孔腔体远、近场电磁屏蔽效能的计算方法，体研究了矩形腔体的屏蔽特性，讨论了各类孔对屏蔽能的影响程度。数值结果表明，理论计算与实验数据吻合较好。     

溢流反弧段水流边界层有关概念的探讨

本文对溢流反孤段水流边界层的定义方法进行分析讨论。在分析及弧段流速分布的基础上提出离心力附加边界层厚度和粗糙度附加边界层厚度的概念,研究了壁面曲率和壁面粗糙度对溢流反弧段边界层发展的影响。     

有限元法应用于微波和光波器件的问题和发展

本文就有限元法应用于微波和光波器件的原理、问题和最新进展作了综合评述。文中讨论了适用于不同问题的变分公式的意义；着重讨论了避免和消除虚模的方法和处理开放边界的技术；还对代表该领域发展趋势的三个方面，即边棱元法。非线性结构及有限元程序的前后处理问题进行了评论和展望。     

步行机攀登横杆的受力模型及分析

针对４足步行机器人的横杆攀登过程，在考虑弹性变形的基础上利用刚度矩阵建立其受力模型，并通过计算机仿真对攀登过程的不同情况进行了分析，其结果为具有攀登功能的步行机构结构设计及控制算法确定提供了理论依据。     

A force modulation study on crystallization process in ferroelectric vinylidene fluoride and trifluoroethylene copolymer films

This paper introduces the Force Modulation technique to the study of crystallization process in ferroelectric vinylidene fluoride and trifluoroethylene copolymer films. Using this technique we have successfully visualized ferroelectric crystalline domains and observed that these ferroelectric domains grow out from amorphous phase, unite into strip-like structures, and finally congregate into a union. Force Modulation can weaken the influence of topography on imaging of ferroelectric domains, and reveal more details, which are difficult to be observed in topographical image.     

A numerical model for induction heating processes coupling electromagnetism and thermomechanics

This paper presents a mathematical and numerical model developed for coupling the various physical phenomena (electromagnetic, thermal and mechanical) taking place in axisymmetrical induction heating processes. All three electromagnetic, thermal and mechanical models are time dependent and take full account of the electromagnetic and thermal non‐linear effect especially with magnetic materials. The electromagnetic problem is discretized and solved in the workpiece, air and inductors. The heat transfer equation and the mechanical equilibrium equations are solved in the workpiece only, both using a finite element method. The mechanical model can take into account thermoelastic–plastic behaviour for the part. The model has been successfully applied to several cases of induction heating. Comparisons between numerical and experimental results show an excellent agreement. Copyright © 2003 John Wiley & Sons, Ltd.     

FAFFA加速的PO-MM研究复杂金属载体上线天线电磁特性

本文提出了一种快速远场近似(FAFFA)加速的混合物理光学矩量法(POMM),利用FAFFA加速计算矩阵方程中的矩阵矢量积,明显提高了计算效率.对物体表面上的远场组之间的耦合作用推导出了一组简洁的计算公式,并分析了计算复杂度.复杂金属组合体上线天线输入导纳、互导纳和方向性图的计算结果与文献结果一致.利用该方法分析计算了一个舰船模型上线天线的电磁特性.数值结果表明了这种方法的正确性和工程应用中的有效性.     

光场力对烧蚀物时空分布的影响

对烧蚀物的时空分布进行了研究。烧蚀物离开靶材表面时的速率分布由蒸发机制决定,在激光作用时间内烧蚀物的传输行为由扩散机制和光场力机制共同决定,激光作用结束后烧蚀物的传输行为由扩散机制单独决定,并解释了烧蚀物的时空分布及烧蚀物趋光运动的现象。