Minimum switching control for adaptive tracking

The switching adaptive control method has been used for quite a few years to solve the adaptive stabilization and model reference adaptive control problems. However, a serious problem with the switching control method is that the number of ‘candidate’ controllers can potentially be very large, especially for multi‐input–multi‐output systems. In this paper, we consider a class of minimum‐phase multi‐input–multi‐output plants with some mild compactness assumptions. Given any polynomial reference input, we provide a switching control law which guarantees exponentially stability of the closed‐loop system with exponential tracking performance. The main contribution of the paper is that we give the minimum number of candidate controllers required for switching. In particular, the number is equal to 2 for single‐input–single‐output plants (one for each sign of the high‐frequency gain), and is equal to 2^m for m‐input–m‐output plants. That is, the number is independent of the degree and the relative degree of the plant. Copyright © 2006 John Wiley & Sons, Ltd.     

A novel robust current control approach using adaptive line enhancer for three‐phase current‐source active power filter

An effective system control method is presented for applying a three‐phase current‐source PWM converter with a deadbeat controller to active power filters (APFs). In the shunt‐type configuration, the APF is controlled such that the current drawn by the APF from the utility is equal to the current harmonics and reactive current required for the load. To attain the time‐optimal response of the APF supply current, a two‐dimensional deadbeat control scheme is applied to APF current control. Furthermore, in order to cancel both the delay in the two‐dimensional deadbeat control scheme and the delay in DSP control strategy, an Adaptive Line Enhancer (ALE) is introduced in order to predict the desired value three sampling periods ahead. ALE has another function of bringing robustness to the deadbeat control system. Due to the ALE, settling time is made short in a transient state. On the other hand, total harmonic distortion (THD) of source currents can be minimized compared to the case where ideal identification of the controlled system can be made. The experimental results obtained from the DSP‐based APF are also reported. The compensating ability of this APF is very high in accuracy and responsiveness although the modulation frequency is rather low. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(1): 50–61, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20014     

生态城市与水利现代化

对天津及其滨海新区生态城市水利建设进行了分析。研究了在淡水资源极度匮乏的条件下,有效开发利用非常规水资源的必要性、重要性和现实性。认为天津市对水资源应遵循节水、治污、高效配置,妥善处理生活、生产、生态之间的关系,力求平衡调配。供水水源应是多元的,增加非常规水资源(污水、海/咸水、雨/洪水)的利用,同时增加可用地下水,外调来水等,逐步进入可持续发展配置。     

康山金矿地质地球化学特征及其成因

康山金矿产在豫西熊耳山古隆起区的结晶基底太华群和盖层中元古界熊耳群地层接触界面附近，矿体严格受构造破碎蚀变带控制。流体包裹体，稳定同位素等研究表明，成矿物质来自太华群变质岩，成矿流体的性质与变质热液截然不同，而与花岗岩浆热液相近似。该矿床的形成与燕山期发生的同构造－花岗岩浆期热液活动有关，金沉淀成矿阶段有大气水的混入。     

Isolation and preliminary characterization of Pichia pinus mutants insensitive to glucose repression

A new method for the isolation of glucose repression-insensitive mutants in the methylotrophic yeast Pichia pinus was developed. The method is based on screening of small suspension samples derived from 2-deoxyglucose-resistant colonies for alcohol oxidase activity. Alcohol oxidase activity was evaluated by determination of formaldehyde excreted by cells. Mutants with glucose non-repressible alcohol oxidase and catalase synthesis were obtained. All mutants grew poorly on D -xylose compared to the wild type, whereas growth on L -arabinose was similar to the wild type. Changes in the glucose transport system were suggested to be responsible for altered growth characteristics and defective glucose repression.     

多孔粒状铵油炸药在边坡预裂爆破中的应用

通过工程实践，介绍了利用多孔粒状铵油炸药进行边坡预裂爆破的设计原理及施工工艺。该技术能确保预裂爆破质量。简化施工工序，大幅度降低爆破成本。技术经济指标优越。     

Extraction of penicillin G from simulated media by an emulsion liquid membrane process

The extraction of penicillin G from simulated media was performed by water/oil/water (w/o/w) emulsion liquid membranes (ELMs) and studied under various operational conditions in a batch system. The degree of extraction achieved was between 80% and 95% under specific conditions. A concentration of greater than nine times the initial concentration of penicillin G in the external phase was obtained in the internal phase. The pH of the internal aqueous solution, containing a basic salt, was theoretically calculated on the basis of the amount of penicillin G transported into the internal phase. The calculated results agreed with the experimental data well and were used to select a suitable type and concentration of a basic salt in the internal phase to give a pH within the range 5 to 8 where penicillin G was stable after the termination of extraction. The extraction of penicillin G was successfully performed by the ELM process with sodium carbonate in the internal phase.