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121.
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The recently established spin-coating electrostatic self-assembly (SCESA) technique has been shown to facilitate not only the rapid fabrication of polyelectrolyte multilayer assemblies, but also allow each layer to be easily controlled on a monomolecular scale by minimizing the film thickness across a substrate surface. In this paper, the influence of polyelectrolyte concentration on the amount and thickness of spin-deposited polymer films has been examined for a multilayer system of poly(allyamine hydrochloride) (PAH) and poly(sodium 4-styrenesulfonate) (PSS), when the washing steps employed for removing weakly bound polyelectrolytes on a resultant film on a substrate are excluded from the standard fabrication procedure of the SCESA method. The thickness of the spin-deposited PAH/PSS bilayer increased linearly for the PSS concentrations in the range from 1 to 10 mM with PAH constant at 1 mM, which demonstrates the uniform deposition of each layer material onto the thin film. The thickness of PAH/PSS bilayers increased from 1.43 ± 0.06 to 3.37 ± 0.08 nm as the PSS concentration increased from 1 to 10 mM, while the PAH concentration was kept constant at 1 mM. The multilayer films were found to be stable in a good solvent (H2O) for at least 30 h, without any noticeable loss of the adsorbed layer component of the polyelectrolyte. This improvement to the SCESA method (exclusion of washing steps) provides a convenient way to create multilayer heterostructures with the thickness of each layer being easily adjusted. 相似文献
123.
Metal matrix composites reinforced by three-dimensional (3-D) continuous network structure reinforcement (3DCNRMMC) are difficult to machine due to serious tool wear and poor surface roughness caused by the brittle and hard reinforcement which interpenetrate into ductile matrix. In order to achieve the approach of low cost of 3DCNRMMC, the machinability of it needs to be understood. The influences of three cutting parameters and volume fraction of reinforcement on cutting force were analyzed in detail. The results indicate that: (1) Due to the brittle phase(s) introduced into ductile matrix of composites, there is a large fluctuation of cutting force causing deterioration of machinability. The fluctuation ranges of cutting forces, initially increase rapidly with the increase of volume fraction of reinforcement and then decrease finally, are largest at the range of the volume fraction of 55–65%; (2) The influence of cutting parameters on cutting force is obvious. With the increases of cutting speed, cutting force decreases gradually unless cutting speed exceeds the value of 209 m/min. Cutting forces increase with increasing feed rate and depth of cut; (3) Owing to the large fluctuation of cutting force, there were some cratered surfaces caused by Si3N4 reinforcement pulling-out and flaking-off. Some brittle phase protruding from the machined surface caused the deterioration of machined surface. 相似文献
124.
振动成型机隔振效果的探讨及实践 总被引:1,自引:0,他引:1
叙述振动成型机的隔振理论及隔振弹簧的计算方法,给出取值范围和调整方法.通过在抚顺铝厂的实践检验,这种目前国内生产最大阳极炭块的振动成型机在λ=4.8时生熟阳极炭块的指标,均达到国家标准的要求,减振效果良好.λ取值的经验为今后研究大型振动成型机提供了参考数据. 相似文献
125.
针对宝钢分公司1580热轧精轧机辊缝零调过程中出现的一些问题,比如轧制力偏差大、辊缝预埋不准确、零调过程受人为因素影响而无法确定统一标准等进行了研究,并提出了解决方案.通过对轧机的刚度实验,找出了轧制力和油柱值之间的线性关系,以此实验数据为基础,改进辊缝零调控制程序,实现了轧制力静偏差的自动调平,零调辊缝的自动预埋等目标.同时通过完善转车联锁条件,杜绝了零调过程中的人为误差.改进前后精轧机辊缝零调数据的对比表明,达到了改进的预期效果,解决了现场存在的实际问题. 相似文献
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128.
刘红 《广东输电与变电技术》2005,(1):20-21
变压器对抗短路强度的要求是很高的。文中介绍了变压器短路时的电动力的作用情况,结合单位实际情况介绍了提高变压器抗短路能力的措施。 相似文献
129.
用常规方法处理乳化油污水比较困难,存在不同的问题,膜分离技术处理乳化油污水具有分离精度高,无二次污染,过程无相变等优点。 相似文献
130.
Stephen O. Dean 《Journal of Fusion Energy》2003,22(3):181-190
This paper summarizes recent progress in fusion Innovative Confinement Concepts (ICC) as reported at the 2004 ICC Workshop held May 25–28, 2004 in Madison, Wisconsin. This was the third in an annual series of workshops on this topic. The purpose of these workshops is to provide a forum for those who are thinking and working beyond what is considered to be the current state of understanding of fusion concepts. 相似文献