基于自适应模糊神经网络辨识的电液伺服系统L2增益设计

为克服电液伺服系统不确定性、非线性、估计误差和干扰等因素对系统稳定性和精度的影响，提出了基于自适应模糊神经网络辨识的电液伺服系统L2增益设计方法。用自适应模糊神经网络在线估计包括系统不确定性和非线性在内的未知动态特性，同时用增益自适应变结构补偿自适应模糊神经网络的估计误差，用系统L2增益设计方法抑制干扰对系统的影响，以期使系统对不确定性和非线性具有鲁棒性，而且从干扰到描述系统跟踪误差的评价函数的L2增益小于指定值。     

一种适用于光伏发电系统的高增益Boost变换器

一般而言,光伏阵列电池的输出电压较低,必须经过升压才能满足后级逆变器的要求.在分析普通单相Boost变换器在高增益变换场合显现的不足的基础上,提出了串入等效电压源的概念,采用耦合电感实现了高增益变换.研究结果表明,其拓展了变换器的电压增益,减小了开关管的电压应力.漏感能量能够无损转移,提高了系统的效率.     

基于自动增益控制的声信号处理电路

介绍了驻极体电容式传声器的工作原理,针对声传感器输出的微弱声信号,及传感器接收的信号幅度强弱相差较大的情况,设计了基于自动增益控制的声信号处理电路;该自动增益控制法使放大电路的增益能够根据输入信号的大小在较大的范围内进行调节,从而保证了声传感器输出信号的信噪比,通过实验验证和分析,证明此处理电路的可行性、实用性和优越性。     

Parametric study of aluminium alloy fouling in marine environment using RSM technique

ABSTRACT

Fouling is known to be a prominent industrial problem which is greatly affected by parameters like temperature, time and flowrate. The aim of this work was to simulate the fouling process in AA 6061 by developing a model through Minitab 16 and evaluate the models. Box Behnken design of Response surface methodology was applied for modelling and optimization of fouling propensity in artificial sea water. A response surface model was obtained and Analysis of Variance was performed to test the significance of the model. Fouling propensity was found in terms of weight gain. An experimental rig consisting of a recirculating loop mimicking the industrial conditions of fouling was used in the study. SEM analysis shows uneven deposits on the metal surface. Sharp, irregular deposits pressed deep into the metal was observed. The finding of this work would enable us to evaluate the individual and interactive effects of the parameters.     

基于全数字伺服控制单元的运动控制算法的研究

文章阐述了基于全数字伺服控制单元的位置控制系统的特点,并且对运动控制算法进行了分析,研究并实现了一种新的基于全数字伺服控制单元的运动控制算法.     

一种大动态范围数字式智能微伏表的设计

本文提出一种用于测量大动态范围变化的弱信号的方法,经实际测试,取得了满意的效果。该方法采用以增益可控部件为核心的步进式数字自动增益控制电路,对信号进行大范围动态压缩;利用８０Ｃ３１微处理机对信号进行实时处理,使系统完成实时显示、故障自检和过载自动报警等功能。它既可作为大动态范围数字式微伏表,又可作为多通道大动态范围低噪声放大器使用。本文主要介绍了系统的基本工作原理、系统的硬件结构及主要软件流程。     

基于自适应进化算法的膜系自动设计

为获得性能更好、更易实现的膜系,提出一种基于自适应进化算法的膜系自动设计方法,并将该方法与常用设计方法进行比较。通过增益平坦滤光片、高反膜的实例优化表明,在相同设计要求下,用该进化算法可以得到更加合理的膜系结构,而且膜系结构简单,设计灵活,容易实现。理论和实践均表明该方法是高效和可靠的。     

Oxidative stability of high-fatty acid rice bran oil at different stages of refining

The contents of natural antioxidants and the oxidative stability of rice bran oils at different refining steps were determined. Tocopherols and oryzanols were constant in crude and degummed oils but decreased in alkali-refined, bleached and deodorized oils. The process of degumming, alkali-refining, bleaching and deodorization removed 34% of the tocopherols and 51% of the oryzanols. During storage of deodorized oil for 7 wk, 34% of the tocopherols and 19% of the oryzanols were lost. The maximum weight gain, peroxide value and anisidine value were obtained from alkali-refined oil during storage. The order of oxidation stability was crude ≥ degummed > bleached = deodorized > alkali-refined oil.     

Influence of the structure in low-Pt loading electrodes for polymer electrolyte fuel cells

The influence of the structure and composition of the electrodes on a polymer electrolyte fuel cell (PEFC) performance has been investigated. Electrodes have been prepared by varying the composition of diffusion and/or catalyst layer. Improvements have been obtained by introducing a hydrophobic carbon layer between the carbon paper and the catalyst layer for the gas diffusion backing. High performance has been achieved with low Pt-loading electrodes (0.15 mg/cm²) by including the ionomer Nafion in the catalyst ink. Electrodes have been characterized by SEM-EDX analyses and electrochemical tests in a 50 cm² single cell.