渣浆泵液力偶合器调速液位控制系统参考模型的模糊控制

将参考模型的概念引入到模糊控制中，用参考模型规定控制系统的期望性能指标。该方法应用于渣浆泵液力偶合器调速液住控制系统，在干扰流量变化很大的情况下，均获得了满意的控制效果。     

A 5.7–6.0 GHz CMOS PLL with low phase noise and −68 dBc reference spur

This paper presents a 5.7–6.0 GHz Phase-Locked Loop (PLL) design using a 130 nm 2P6M CMOS process. We propose to suppress reference spur through reducing the current mismatch in charge pump (CP), controlling the delay time in phase frequency detector (PFD), and using a smaller VCO gain (KVCO). With a reference frequency of 32.768 MHz, chip measurement results show that the frequency tuning range is 5.7–6.0 GHz, the reference spur is −68 dBc, the phase noise levels are −109 dBc/Hz and −135 dBc/Hz at 1 MHz and 10 MHz offset respectively for 5.835 GHz. Compared with existing designs in the literature, this work’s reference spur is improved by at least 17% and its phase noise is the lowest. Under a 1.5 V supply voltage, the power dissipation with an output buffer of the PLL is 12 mW.     

Comparative studies of configurations and preparation methods for direct methanol fuel cell electrodes

Catalyst-coated membrane (CCM) and catalyzed diffusion medium (CDM) prepared either by brush painting method or by spraying method were compared for direct methanol fuel cell (DMFC) anode and cathode. The pore structure and the morphology of the electrodes were characterized by mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). Internal resistance corrected polarization curves were employed to separate the contribution of each compartment of the membrane electrode assembly (MEA) to the overall polarization. It was shown that the increased mass transport resistance in the anode diffusion layer made the anode in CDM form act as the methanol barrier. The CCM configuration and the increased pores in micron scales in the catalyst layer were in favor of improving the performance of both anode and cathode. Accounting for the effect of methanol permeation, the combination of the anode in CDM form prepared by brush painting method and the cathode in CCM form prepared by spraying method was finally selected as the optimized configuration for MEA, which had the highest DMFC performance under near-ambient conditions.     

电液非线性系统自适应控制的非线性参考模型方法

本文提出了通过构造与受控对象具有相同非线性特性的参考模型，并借助仿射变换和非线性反馈使参考模型线性化来实现对电液非线性仿射系统的模型跟随自适应控制方法，并通过分析和仿真说明了这种AMFC系统能够确保被控对象准确跟随参考模型的输出。     

Estimation of ASTM E-1921 reference temperature from Charpy tests: Charpy energy-fracture toughness correlation method

In this paper, some of the older and newer Charpy-fracture toughness correlations have been examined and new correlations have been developed for predicting the ASTM E-1921 standard reference temperature, T₀. The results have been applied to some selected new steels and compared with measured T₀, where available. It is found that the predicted reference temperature from the new procedure gives reliable and acceptably conservative engineering estimate of T₀. Predicted values of reference temperatures under dynamic conditions from these T₀ using Wallin’s strain rate shift equation agree well with measured dynamic values for a few steels giving added support to the new procedure.     

Elastic-plastic fracture mechanics analyses of circumferential through-wall cracks between elbows and pipes

The present work proposes a method for elastic-plastic fracture mechanics analysis of the circumferential through-wall crack in weldment joining elbows and attached straight pipes, subject to in-plane bending. Heterogeneous nature of weldment is not explicitly considered and thus, the proposed method assumes cracks in homogeneous materials. Based on small strain finite element limit analyses using elastic-perfectly plastic materials, closed-form limit loads for circumferential through-wall cracks between elbows and straight pipes under bending are given. Then applicability of the reference stress-based method to approximately estimate J and crack opening displacement (COD) is evaluated. It was found that the limit moments for circumferential cracks between elbows and attached straight pipes can be much lower than those for cracks in straight pipes, particularly for a crack length of less than 30% of the circumference; this result is of great interest in practical cases. This result implies that, if one assumes that the crack locates in the straight pipe, limit moments could be overestimated significantly, and accordingly, reference stress-based J and COD could be significantly overestimated. For the leak-before-break analysis, accurate J and COD estimation equations based on the reference stress approach are proposed.     

Practical approach to tuning MPC

This paper presents the results of a heuristic approach for developing model predictive control (MPC) tuning rules. The tuning has been applied and tested in easy-to-use MPC. Process modeling in this MPC uses normalized input/ output range. As a result there is no need for tuning outputs, a procedure known as adjusting equal concern error. Penalties on moves are set as a function of process dead time as the primary factor, with some correction from process gain. The default calculation delivers robust control, which tolerates up to triple increase in process static gain. If control is too aggressive, further on-line adjustment can be done by set point reference trajectory. Test results show that this tuning is robust for process gain change, however, it is much less efficient in compensating for process dead-time changes. It was found that dead-time mismatch is much better compensated with the model correction filter. Combining the three handles, i.e., penalties on moves, reference trajectory, and model filter, easy and intuitively understandable MPC tuning was achieved. The findings are illustrated by numerous MPC simulated tests.     

企业集成平台参考模型与实现体系研究

分析了面向协同电子商务的企业集成平台的功能和信息模型 ,提出了一种面向信息、应用、服务到企业业务流程的全方位协同的集成平台参考实现体系。它以支持企业协同电子商务为特性 ,实现不同层次的企业集成     

齿轮－凸轮组合机构的参数取值研究和优化设计

本文讨论了实现停歇－正弦加速度规律输出的单凸角齿洛－凸轮组合机构，指出了其参数之间的关系，研究了该机构体积优化问题，还给出了优化值表。     

参考模型为一的液压自适应控制系统的研究

根据ＭＲＡＣＳ自适应控制理论，阐述了即使参考模型脉冲传递函数为一，也能实现被控系统模型完全匹配，讨论了这种系统自适应控制目的的实现问题。通过在液压系统中的应用及在线实时控制试验研究，说明这种自适应控制系统的可行性与实用性。