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71.
72.
根据MCP标准函数,利用控制器标准传递函数设计方法推导得出了一种新的PID参数整定公式.通过理论分析和仿真试验,验证了用MCP法公式整定的系统具有超调量小和鲁棒性高的优点. 相似文献
73.
采用分子动力学模拟方法研究了298.15 K、0.1 MPa下摩尔分数为0.05~0.95的水对室温熔盐1-丁基吡啶四氟硼酸([Bpy]BF4)结构与性质的影响.获得了体系的径向分布函数、配位数和空间分布函数等微观结构及其密度、自扩散系数、电导率和粘度等物理化学性质.模拟密度与实验结果符合很好;体系中各组分间的径向分布函数和配位数均随水摩尔分数的增加有规律的变化;获得了各组分之间的三维空间分布情况;随水摩尔分数的增加,阴阳离子之间的相互作用被削弱,同时水与阴离子、阳离子及水分子之间的相互作用逐渐增强,水、阴离子和阳离子的自扩散系数增大,体系粘度降低,电导率升高.研究工作揭示了水对[Bpy]BF4中各组分的存在形式、相互作用及其对体系物理化学及输运性质的影响,为其在冶金与材料制备方面的应用提供理论依据和参考. 相似文献
74.
吴大兵 《重庆理工大学学报(自然科学版)》2014,(9):95-100
人民政协作为我国政治生活中的重要方式,其特有的职能定位赋予了它在我国经济经济发展方式转变中不可或缺的重要作用。在经济发展方式转变过程中,它对于发展的顶层设计、具体过程的监督、行进中资源的整合等发挥着不可替代的作用。基于其现实中所存在的困境,充分发挥政协职能,其着力点在于优化环境、打造平台、完善制度和创新机制。 相似文献
75.
Kshitij Mall Ehsan Taheri Prathamesh Prabhu 《American Institute of Chemical Engineers》2021,67(6):e17209
This study investigates the application of a recently developed construct, the uniform trigonometrization method (UTM), to the singular control problems in chemical engineering. The UTM involves minimal modifications to the original problem, thereby generating near-singular control solutions that can be used for conceptual design and serve as an alternate to direct techniques like nested and simultaneous approaches. Eight classical singular control problems with known analytical solutions and three complex singular control problems from chemical engineering domain are solved in this study. The results obtained using the UTM for these problems are found to match well with the literature and are of higher resolution as compared to the results obtained using a direct pseudospectral-based solver. The ability of the UTM to handle complex chemical engineering problems with both singular controls and state path constraints has also been demonstrated in this study. 相似文献
76.
77.
F.c.c. solid Co---Pd alloys have been investigated thermodynamically by means of computer-aided Knudsen cell mass spectrometry. Thermodynamic evaluation has been performed by applying the “digital intensity ratio” method. The thermodynamic excess properties can be described algebraically by means of thermodynamically adapted power series with two adjustable parameters, i.e. C1G (−20 810 + 9.608T) J mol−1) and C2G (−30 720 + 6.78T) J mol−1). At 1470 K, f.c.c. solid Co---Pd alloys are characterized by negative molar excess Gibbs energies GE, exothermic molar heats of mixing (HE) and small negative molar excess entropies SE. At 1470 K, the minimum GE value is −4600 J mol−1 (61.9 at.% Pd), the minimum HE value is −9400 J mol−1 (59.5 at.% Pd) and the minimum SE value is −3.3 J mol−1 K−1 (55.9 at.% Pd). The thermodynamic activities of Co show small positive deviations from the ideal case for the Co-rich alloys (xPd < 0.34), and negative deviations from Raoults' law for alloys with higher Pd contents. The Pd activities aPd show negative deviations from the ideal case for all compositions. The phase diagram has been computed by means of a generally applicable procedure for the calculation of the equilibrium compositions of coexisting phases. This was achieved using the results of this work, thermodynamic data from earlier mass spectrometric studies on the liquid phase, and literature data for the heat capacities and enthalpies of Co and Pd. 相似文献
78.
We consider an initial-boundary-value problem for a time-fractional diffusion equation with initial condition u0(x) and homogeneous Dirichlet boundary conditions in a bounded interval [0, L]. We study a semidiscrete approximation scheme based on the pseudo-spectral method on Chebyshev–Gauss–Lobatto nodes. In order to preserve the high accuracy of the spectral approximation we use an approach based on the evaluation of the Mittag-Leffler function on matrix arguments for the integration along the time variable. Some examples are presented and numerical experiments illustrate the effectiveness of the proposed approach. 相似文献
79.
In this paper, a computational method for numerical solution of a class of integro-differential equations with a weakly singular kernel of fractional order which is based on Cos and Sin (CAS) wavelets and block pulse functions is introduced. Approximation of the arbitrary order weakly singular integral is also obtained. The fractional integro-differential equations with weakly singular kernel are transformed into a system of algebraic equations by using the operational matrix of fractional integration of CAS wavelets. The error analysis of CAS wavelets is given. Finally, the results of some numerical examples support the validity and applicability of the approach. 相似文献
80.