基于干扰观测器的多光伏光柴混合系统协调控制研究

提出了一种基于干扰观测器的多光伏光柴混合系统协调控制方法,并与采用最大功率跟踪控制而不加协调的多光伏系统的供电效果进行了对比.仿真结果证明,该方法减小了光柴混合系统的频率偏差,并且使各个光伏系统获得了较大功率输出.     

DBGRIP: A learning expert system for detailed selection of robot grippers

A practical expert system for selecting commercially available robot grippers is presented. The system is implemented using a powerful hybrid expert system development tool coupled with a database management program. The knowledge base employed by the expert system in the selection processes is outlined. Details of the main features of the system are given, including its ability to learn by positive reinforcement of past experience.     

Lethality calculation for thermal processes with different heating and cooling rates

In many thermal processes, the time constants f_h and f_c for the heating and cooling periods differ. This can cause difficulties in calculating the process lethality. This paper presents a simple method for taking into account this change in the time constant. The author's formula method is tested against simulated data from finite-difference computations, both for f_h=f_c and for f_h≠f_c , and found to be at least as accurate as the best previous formula method.     

Properties of Anthocyanins from Grape Cell Culture

Color and thermal- and pH-stability of anthocyanins from a grape cell suspension culture were compared with those of commercial food colorants using Hunter and spectrophotometric analysis. At pH 3, grape cell anthocyanins showed color vividness (Chroma) similar to red cabbage and higher than that of other samples and a hue (Theta) similar to purple corn and redder than other samples. Brown oxidized phenolics were absent from the cell culture and red cabbage preparations, but were found in other samples. Color loss during incubation at 30 and 95°C, pH 3 and during an increase in pH from 3 to 5 was more severe for cell culture than red cabbage anthocyanins probably indicating they were intrinsically more sensitive.     

永磁同步风力发电系统的分数阶比例积分控制算法研究

将分数阶比例积分(PIλ)控制器应用于直驱型永磁同步风力发电系统,来达到实现系统高性能控制的目的。重点研究了永磁同步风力发电系统的分数阶PIλ控制器参数设计方法。通过分数阶PIλ控制器系统的仿真研究与试验分析,结果表明:采用分数阶PIλ控制器的系统具有较快的响应速度和较高的功率输出性能,具有一定的发展潜力和实用价值。     

选择LDO的方法 便携应用在基本条件之外提出更多要求

在选择低压降线性调节器(LDO)时,需要考虑的基本问题包括输入电压范围、预期输出电压、负载电流范围及其封装的功耗能力.但是,便携式应用通常还需要考虑更多问题,比如接地电流或静态电流(IGND或IQ)、电源波纹抑制比(PSRR)、噪声与封装大小等通常也是为便携式应用决定最佳LDO选择的考虑要素.     

Studies on the development of texturized vegetable products by the extrusion process.

Thiamin retention in extruded cowpea, mungbean, defatted soybean and air classified mungbean products was studied by a least squares regression equation using process temperature, screw speed, buffer pH and moisture content as the major independent variables. The increase in process temperature, pH and screw speed variables effected the decrease of thiamin retention values, while the increase in moisture content increased retention. The heat generation due to increase of stress force caused by increased screw speed presumably resulted in the thiamin retention values which were lower than expected. The carbohydrate and protein of the feed material flours pro-tected the thiamin during the thermoplastic extrusion process.     

Modelling and prediction using GMDH networks of Adalines with nonlinear preprocessors

This paper presents the results of an investigation into the use of GMDH neural networks for system modelling and prediction. A number of Adalines with nonlinear preprocessors were trained to yield a GMDH neural network. The training was carried out by applying the Widrow-Hoff learning rule. The structure of the network, i.e. the number of layers and the number of Adalines in each layer, was determined during training. The results obtained have shown that this type of network can successfully be employed for various system modelling and prediction tasks     

Optimal maintenance policies for several imperfect repair models

Three new maintenance models, two imperfect preventive maintenance models and a cost limit (imperfect) repair model are proposed. In these models the imperfect maintenance is treated in such a way that after maintenance the lifetime of a unit will be decreased to a fraction of the one immediately preceding it, and the imperfect repair time as well as cost increases as the number of imperfect repairs increases. The long-run expected maintenance cost rates and corresponding asymptotic average availabilities for these three models are derived. The optimum maintenance policies subject to maintenance time are discussed. Some constraint optimization problems related to maintenance cost rate and availability are presented. Finally, numerical examples are given.