浅谈集中监控开关实传试验的“三步控制法”

变电站的无人值守模式下,集中监控的变电站开关需完成远方遥控实传试验。试验操作过程存在业务交叉联系、操作业务界面较为复杂等问题。在分析集中监控的状况、运行维护水平、现场设备状态检修等实际的情况下,通过"三步控制法"管控开关实传试验风险的研究与实施,对开关实传试验操作做出了规范,防止了监控误操作开关事故的发生,确保了电网的安全稳定运行。

Experimental analysis of the slip sinkage effect based on real vehicle test

To improve the semi-empirical model, the slip sinkage effect is analyzed based on the real vehicle test. A dynamic testing system is used to gain the dynamic responses of wheel-soil interactions, The Gauss-Newton algorithm is adopted to estimate the undetermined parameters involved in the slip sinkage models. Wong＇s original model is compared with three typical slip sinkage models on the prediction performance of a drawbar pull. The maximum error rate, root mean squared error and correlation coefficient are utilized to evaluate the performance. The results indicate that the slip sinkage models outperform Wong＇s model and greatly improve the prediction accuracy. Lyasko＇s model is confirmed as an outstanding one for its comprehensive performance. Hence, the existence of the slip sinkage effect is validated. Lyasko＇s model is selected as an optimal one for the practical evaluation of military vehicle trafficability.

500 kV变电站调控端程序化操作的关键技术研究

文章着眼于推进公司调控端远方程序化操作实用化,探讨了调控端程序化操作实现的难点。围绕切实可行的500 kV变电站闸刀实传试验方法,基于图像识别技术的闸刀状态“双确认”手段,基于D5000系统的闸刀远方操作防误技术和程序化操作中的防误技术措施,程序化操作对象及技术要求,程序化操作票存储和执行实现方案以及程序化操作可靠性要求及实现方案等五个方面进行了研究分析,有助于调控端远方程序化操作的实施和开展,可以减少变电站操作时间,杜绝或减少因人为原因导致的误操作,有助于电网运行管理水平的提升。

Characteristics and applications of gas desorption with excavation disturbances in coal mining

According to the deficiency of experiment system for gas adsorption and desorption in coal mass, a large scale experiment system is developed independently by researchers. This experiment system is composed of primary and auxiliary boxes, power transmission system, mining system, loading system, gas charging system, data monitoring and intelligent acquisition system. The maximum experiment coal consumption is 1200 kg, the mining system is developed to conduct experiment for gas desorption under excavating disturbance, and the plane-charging cribriform ventilation device is developed to realize uniform ventilation for experiment coal sample, which is accord with the actual gas source situation of coal bed. The desorption characteristics of gas in coal are experimentally studied under the conditions of nature and mining using the experiment system. The results show that, compare with nature condition, the permeability of coal and the velocity of gas desorption could significantly increase under the influence of coal pressure relief and destruction caused by mining, and the degree of gas desorption could somewhat increase too. Finally, pressure relief gas extraction of current seam and adjacent seams after mining in a certain coal mine of Yangquan mining area are introduced, and the gas desorption experiment results is verified by analyzing the effect of gas extraction.

Application of Genetic Algorithms to Optimize Neural Networks for Selected Tribological Tests

This paper presents a method of determining the friction coefficient in metal forming using multilayer artificial neural networks based on experimental data obtained from strip drawing test. The number of input variables of the artificial neural network has been optimized using genetic algorithm. This process is based on surface parameters of the sheet and dies, sheet material parameters and clamping force as input parameters to train the neural network. In addition to demonstrating the fact that regression statistics model using genetic selection and intelligent problem solver are better than models without preprocessing of input data, the sensitivity analysis of the input variables has been conducted. This avoids the time-consuming testing of neurons in finding the best network architecture. The obtained results from this study have also pointed out that genetic algorithm can successfully be applied to optimize the training set and the outputs agree with experimental results. This allows reduction or elimination of expensive experimental tests to determine friction coefficient value.

A Study on Constructing Sense Relations

An empirical study is conducted to examine the effect of constructing sense relations in vocabulary teaching. Fifty subjects are divided into two groups： the controlled group which was taught with traditional method, and the experimental group to which sense relation strategy was applied in vocabulary instruction. At the end of the experiment instruction, a test （depth of vocabulary knowledge measure） was given to examine the teaching effects of the two vocabulary teaching strategies. The target words in the tests were selected from the word list that had been taught during the experiment time. A delayed vocabulary posttest was given to the subjects two weeks after examining the long-term retention effect. The third test was administered with different targets words which were selected from a different intensive reading material which wass new to the subjects. The experiment proves that constructing sense relations in vocabulary teaching could produce satisfactory results by enhancing students＇ lexical capacity and long-term retention.

Asiatic Callosciurus squirrels as seed dispersers of exotic plants in the Pampas

Seed dispersal by exotic mammals exemplifies mutualistic interactions that can modify the habitat by facilitating the establishment of certain species. We examined the potential for endozoochoric dispersal of exotic plants by Callosciurus erythraeus introduced in the Pampas Region of Argentina. We identified and characterized entire and damaged seeds found in squirrel faeces and evaluated the germination capacity and viability of entire seeds in laboratory assays. We collected 120 samples of squirrel faeces that contained 883 pellets in seasonal surveys conducted between July 2011 and June 2012 at 3 study sites within the main invasion focus of C. erythraeus in Argentina. We found 226 entire seeds in 21% of the samples belonging to 4 species of exotic trees and shrubs. Germination in laboratory assays was recorded for Morus alba and Casuarina sp.; however, germination percentage and rate was higher for seeds obtained from the fruits than for seeds obtained from the faeces. The largest size of entire seeds found in the faeces was 4.2 ~ 4.0 ram, whereas the damaged seeds had at least 1 dimension ≥ 4.7 ram. Our results indi- cated that C. erythraeus can disperse viable seeds of at least 2 species of exotic trees. C. erythraeus predated seeds of other naturalized species in the region. The morphometric description suggested a restriction on the maximum size for the passage of entire seeds through the digestive tract of squirrels, which provides useful information to predict its role as a potential disperser or predator of other species in other invaded communities.

Design and Implementation of a Wearable Body Area Sensor Network for Distributed FES System

A wearable body area sensor network(WBASN) was designed and implemented to monitor movement information of stroke patients in real time. The sensor system was combined with a previously developed distributed functional electrical stimulation(d FES) system, which is a promising technology for motor rehabilitation of stroke patients. Movement information could be useful in outcome assessment of rehabilitation, or for closed-loop adaptive stimulation during rehabilitation. In addition,a short-latency, low-power communication protocol was developed to meet the clinical requirements of energy efficiency and high rate of data feed-through. The prototype of the WBASN was tested in preliminary human experiments. Experimental results demonstrate the feasibility of the proposed wearable body area sensor network in monitoring arm movements on healthy subjects.