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61.
In this paper, adaptive set‐point regulation controllers for discrete‐time nonlinear systems are constructed. The system to be controlled is assumed to have a parametric uncertainty, and an excitation signal is used in order to obtain the parameter estimate. The proposed controller belongs to the category of indirect adaptive controllers, and its construction is based on the policy of calculating the control input rather than that of obtaining a control law. The proposed method solves the adaptive set‐point regulation problem under the assumption that the target state is reachable for each fixed parameter value. Additional feature of the proposed method is that Lyapunov‐like functions have not been used in the construction of the controllers. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
62.
Thermal effects on welded joints between fiber-reinforced thermoplastics (FRTPs) and metals have been investigated theoretically and experimentally. Because FRTPs use thermoplastics as the matrix resin, they have advantages over fiber-reinforced thermoset plastics (FRPs or FRSPs), including the ability to be welded. When dissimilar materials are welded together, however, thermal stress occurs due to the different thermal expansions of the materials and affects the energy release rate of the joint. Therefore, a method for evaluating the true energy release rate, including the effect of thermal stress, is necessary for strength evaluation tests. Although several theories that compensate for the thermal stress and evaluate the true energy release rate have already been proposed, they require parameters that are difficult to measure. Therefore, it is difficult to apply them in experimental investigations. In this article, a theoretical method with easily measurable parameters is proposed to calculate the energy release rate of welded double cantilever beam (DCB) joints. The effect of the thermal stress on the critical energy release rate is discussed in terms of the experimental results of a welded DCB specimen composed of a FRTP and an aluminum alloy. 相似文献
63.
Daisuke Shimamoto Kimiyasu Sato Yoshiki Sugimoto Yuji Hotta 《International Journal of Applied Ceramic Technology》2019,16(6):2380-2384
Carbon fiber reinforced plastic (CFRP) composites have been considered quite eminent structural materials. For more extensive applications, however, more rapid forming methods of the CFRP composites are required. As for CFRP composites with thermoplastic matrices, microwave heating and pressing with ceramic molds should be promising. In the present work, zirconia molds with varied thermal conductivity were employed to give a desired shape to the CFRP composites heated with microwave irradiation. Experimental results showed that use of the zirconia molds with smaller thermal conductivity results in shorter necessary time for the forming process. Mechanism of the notable change in the heating efficiency is discussed as well. 相似文献
64.
Inside Cover: Biosynthetic Gene Cluster for Surugamide A Encompasses an Unrelated Decapeptide,Surugamide F (ChemBioChem 18/2016) 下载免费PDF全文
65.
66.
This paper discusses the complexity of packingk-chains (simple paths of lengthk) into an undirected graph; the chains packed must be either vertex-disjoint or edge-disjoint. Linear-time algorithms are given for both problems when the graph is a tree, and for the edge-disjoint packing problem when the graph is general andk = 2. The vertex-disjoint packing problem for general graphs is shown to be NP-complete even when the graph has maximum degree three andk = 2. Similarly the edge-disjoint packing problem is NP-complete even when the graph has maximum degree four andk = 3. 相似文献
67.
Phase relations for the Al2O3-CaF2-SiO2 system were investigated from 1673 to 1723 K. The hotfilament technique was applied to observe a two-liquid region and liquidus
for the ternary system. The liquidus saturated with SiO2 was investigated at 1673 K by using the hot-filament technique and the chemical equilibrium technique. In this system, the
addition of Al2O3 to the CaF2-SiO2 system reduces the congruent temperature. A small substitution of Al2O3 for CaF2 increases the solubility of SiO2, namely, if the region of liquid phase could be enlarged. These results suggest that Al2O3 would be an effective substitute of CaF2 in slag for steelmaking. 相似文献
68.
Shigeru Hanba 《国际强度与非线性控制杂志
》2008,18(17):1592-1606
》2008,18(17):1592-1606
In constructing a globally convergent numerical nonlinear observer of Newton‐type for a continuous‐time nonlinear system, a globally convergent nonlinear equation solver with a guaranteed rate of convergence is necessary. In particular, the solver should be Jacobian free, because an analytic form of the state transition map of the nonlinear system is generally unavailable. In this paper, two Jacobian‐free nonlinear equation solvers of pseudo‐Newton type that fulfill these requirements are proposed. One of them is based on the finite difference approximation of the Jacobian with variable step size together with the line search. The other uses a similar idea, but the estimate of the Jacobian is mostly updated through a BFGS‐type law. Then, by using these solvers, globally stable numerical nonlinear observers are constructed. Numerical results are included to illustrate the effectiveness of the proposed methods. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
69.
Shigeru Okada Toetsu Shishido Takao Mori Kiyokata Iizumi Kunio Kudou Kazuo Nakajima 《Journal of Alloys and Compounds》2008,458(1-2):297-301
LEAlB14 (orthorhombic, Imam) (LE = Li, Mg) crystals were grown using metal salts (Li2CO3, LiF, LiI, MgO, MgF2, MgI2) and crystalline boron from a high-temperature aluminium metal flux. The growth conditions for growing LEAlB14 were established using the starting mixtures of B/LE = 2.0, and Al metal was added to each mixture at a mass ratio of 1:15–20. LEAlB14 crystals from the Al-self flux using metal salts could be obtained from all the different salts. The maximum dimensions of LiAlB14 and MgAlB14 crystals were approximately 18 and 12 mm for the crystals obtained from LiF and MgF2. The unit-cell parameters of as-grown LEAlB14 are as follows: for LiAlB14, obtained from LiF, a = 0.5846 (2) nm, b = 0.8144 (2) nm, c = 1.0355 (3) nm, V = 0.4930 (2) nm3: for MgAlB14, obtained from MgF2, a = 0.5845 (2) nm, b = 0.8114 (2) nm, c = 1.0330 (3) nm, V = 0.4899 (3) nm3. Microhardness, oxidation resistance and magnetic susceptibility of these materials are described in detail. 相似文献
70.