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991.
Serna R Gonzalo J Suárez-García A Afonso CN Barnes JP Petford-Long AK Doole RC Hole D 《Journal of microscopy》2001,201(2):250-255
Pulsed laser deposition in vacuum has been used to develop metal-oxide nanocomposite films with well controlled structural quality. Results for the copper–aluminium oxide (Cu:Al2 O3 ) system are used to illustrate the main morphological and structural features of these films. High resolution transmission electron microscopy (TEM) analysis shows that the films consist of Cu nanocrystals with average dimensions that can be controlled between 2 nm and 10 nm embedded in an amorphous Al2 O3 matrix. It is observed that the in-plane shape of the nanocrystals evolves from circular to elongated, and the number of nanocrystals per unit area decreases as their size increases. This evolution is explained in terms of nucleation at the substrate surface and coalescence during the later stages of growth. The thermal stability of the films has been studied by in situ TEM annealing and no transformation could be observed up to about 800 °C when partial crystallization of the Al2 O3 starts. 相似文献
992.
该文将模糊控制中的“可变论域”思想和参数模糊自整定方法相结合,提出一种“可变论域”的模糊自整定控制方法,并将它成功应用在转台的速率控制中,为模糊控制在工程中的应用提供了一种新的、简单易行的途径。 相似文献
993.
994.
Early detection and diagnosis of incipient induction machine faults increases machinery availability, reduces consequential
damage, and improves operational efficiency. However, fault detection using analytical methods is not always possible because
it requires perfect knowledge of a process model. This paper proposes a neural network based expert system for diagnosing
problems with induction motors using vibration analysis. The short-time Fourier transform (STFT) is used to process the quasi-steady
vibration signals, and the neural network is trained and tested using the vibration spectra. The efficiency of the developed
neural network expert system is evaluated. The results show that a neural network expert system can be developed based on
vibration measurements acquired on-line from the machine. 相似文献
995.
基于双圆弧齿轮的齿形特点 ,结合弧齿锥齿轮的加工原理 ,进行双圆弧弧齿锥齿轮的切齿啮合分析 ,得到了切齿啮合过程中的啮合方程、产形轮齿面方程以及双圆弧弧齿锥齿轮的通用齿面方程表达式 相似文献
996.
本文通过对吉林省和龙火车站滑坡特征的描述,详细论述了三种防治滑坡的方法,即地表水汇流排泄、微型抗滑桩和地下水排泄的防治方法. 相似文献
997.
郭惠玲 《武汉理工大学学报(材料科学英文版)》2018,33(3):559-565
A facile approach has been developed to synthesize Fe3O4@PAM (polyacrylamide) nanoparticles (NPs) with carboxyl groups on the surfaces by copolymerization with acrylamide and acrylic acid in Fe3O4 NPs aqueous suspension. Nitrilotriacetic acid (NTA) was conjugated to the magnetic NPs via well-known carboniimide chemistry using EDC and NHS. The Ni2+ ions loaded on the surface of NPs provide abundant docking sites for immobilization of His-tagged green fluorescent proteins (His-tagged GFP). The high magnetic property of Fe3O4@PAM@NTA-Ni2+ allows an easy separation of the NPs from solution under an external magnetic field, with high His-tagged protein binding capacity (42 μg protein/mg of NPs). The NPs can be recycled for at least four times without significant loss of binding capacity to proteins. These materials show great potential to separate His-tagged protein with low-cost purification at industrial scale. 相似文献
998.
Considering the current environmental issues with petro-polymers, castor oil is a promising green alternative to the polyols to be used as the main raw material for polyurethane. However, the basic information regarding the processability of castor oil-based polyol (CP) such as its miscibility in different solvents is still elusive. Herein we have investigated the phase equilibria and surface tension of various CP solutions using thermo-optical analysis and pendent drop method, respectively. The modified double lattice (MDL) model was employed to theoretically describe those phase equilibria and surface behaviors. The phase diagrams of CPs/methanol binary systems represent upper critical solution temperature (UCST) behaviors, and CPs/methanol/water ternary systems show Treybal Type 2 behaviors. The surface tension results exhibit preferential solvent adsorption, which means affinity of the solvent to be present in surface is higher than that of the polymer. The calculated results showed good agreement with the experimental observations. 相似文献
999.
1000.
Abstract Improved robust CMAC control schemes are proposed for tracing dynamic trajectories in this paper. There are two main structures in the proposed control schemes: one is the robust controller and the other is the improved CMAC network. The robust controller technique can achieve a certain goal without concern for instability of the controlled system in the presence of significant plant uncertainties if the nominal parameter is roughly estimated. Next, in order to reduce the tracing error, a suitable nominal parameter needs to be chosen. Thus, the improved CMAC learning approach under the robust control structure, using the concept of credit assignment, will be employed to determine control variables that can trace other states repeatedly during control processes. Finally, simulation results demonstrate the capability of the proposed control schemes to trace dynamic trajectories. 相似文献