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61.
The effect of the acidic hairy layer length on the interdiffusion of polymer between particles and as a consequence on the mechanical properties of the films produced from waterborne coatings has been studied. In order to isolate this effect, latexes with the same particle diameter and molecular weight but stabilized with poly(acrylic acid)-block-poly(butyl acrylate) (PAA-b-PBA) block copolymers of controlled and different lengths were prepared. Tensile strength measurements showed at the macroscopic level that the presence of AA chains in the particle surface reduced the mechanical properties of the films dried at room temperature, being its effect worse the longer the AA chain length. Higher annealing temperatures erased the negative effect of the acidic hairy layer on mechanical properties. The neutralization with NaOH instead of with NH4OH also led to worse mechanical properties. These macroscopic results were supported by Fluorescence Resonance Energy Transfer (FRET) experiments that showed that at the microscopic level, the extent of interdiffusion occurred slower when the AA chains in the particles surface increased, the annealing temperature was lower and when NaOH was used as neutralizing agent instead of NH4OH. 相似文献
62.
Chemical processes are becoming increasingly complicated, leading to an increase in process variables and more complex relationships among them. The vine copula has a significant advantage in portraying the dependence of high-dimensional variables. However, as the dimensions increase, the vine copula model incurs a high computational load; such pressure greatly reduces model efficiency. Relationships among variables in the industrial process are complex. Different variables may be strongly or weakly associated or even independent. This paper proposes a process monitoring method based on correlation variable classification and vine copula. The weighted correlation measure is first used to divide variables into a correlated subspace and weakly correlated subspace. Then, two vine structures, C-vine and D-vine, are applied to the correlated and weakly correlated subspaces, respectively. This method takes advantage of C-vine for correlated variables and the flexibility of D-vine for weakly correlated variables. Finally, comprehensive statistics are established based on different subspaces. Monitoring results of the numerical system and the Tennessee Eastman process demonstrate the effectiveness and validity of the proposed method. 相似文献
63.
64.
高频结构仿真器(HFSS)是一种微波器件设计软件,该软件界面友好,通过仿真计算减小了调试工作量,使得微波器件的设计变得简单易行。本文利用HFSS对波导魔T进行了仿真分析,得到了该器件的S参数和动、静态场的分布情况,并对该器件进行了优化设计。 相似文献
65.
66.
We consider the Mayer optimal control problem with dynamics given by a nonconvex differential inclusion, whose trajectories are constrained to a given set and we obtain a relation between the costate function that appears in the maximum principle and the value function. This relation extends the known conditions existing in the literature for unconstrained problems to those for problems under state constraints. 相似文献
67.
68.
湘中海相浅层湘冷1井酸压工艺研究及应用 总被引:2,自引:0,他引:2
湘冷1井具有气层埋藏浅(400m-500m)、纵向上裂隙发育的特点,属低孔、低渗的含泥质灰岩致密储层。大量室内实验和研究采用“前置液酸压+闭合酸化”工艺技术,并优选了相应降阻酸和闭合酸配方。通过酸压实现了该井工业油气流的突破,取得了明显的增产效果,为新区海相浅层气的开发探索出了一套成熟的改造增产措施。 相似文献
69.
提出一种进行模拟计算电动机启动过程中各参数的新方法。利用电机运行理论,结合物体定轴转动定律,推导出电机运行参数随时间变化的函数关系式。将计算公式离散化后,对电机启动过程运行规律进行求解。实例计算了一种型号潜油三相电动机启动时电动机定子电流、转子电流、激磁电流、扭转力矩、转速参数及效率参数等随时间或转差率的变化规律,其变化曲线与试验结果基本一致,说明提出的计算方法是有效、正确、适用的。 相似文献
70.
Dong Yuancheng Duan Yongsheng Zou Shiying Wang Jian Ye Xingbin Yang Jianxin 《中国炼油与石油化工》2006,(3):27-32
1 Introduction With the successful completion of the construction of the China-Kazakhstan oil pipeline the refinery at Dushanzi Pet- rochemical Company will process the Kazakhstan-Russian mixed crude at full steam starting 2007. The high sulfur, nitro- gen and heavy metals contents in the Kazakhstan-Russian mixed crude would have a serious impact on the secondary processing units of the Dushanzi refinery, in particular on the distillate hydrocracking unit, which mainly operates on vacuum g… 相似文献