基于Smith预估控制器的监控AGC在冷连轧机上的应用

针对带钢冷连轧机厚度控制这一纯滞后系统,常规监控AGC很难取得良好的控制性能,基于Smith预估控制器的监控AGC系统经预估补偿后可以使闭环系统特征方程中不含时滞项,从而获得更好的控制效果。基于调速调厚控制理念,建立监控AGC系统的控制模型,给出了输入量的获取方法和滤波处理方法,同时给出了速度修正量和解耦环节的计算模型...     

辊缝型监控AGC纯滞后补偿控制器的算法设计及应用

针对辊缝型监控AGC控制时的滞后特点,采用新型Smith预估策略对监控AGC系统进行纯滞后补偿.根据监控AGC各个主要控制环节的传递函数,推导纯滞后补偿控制器的理论预估模型.采用最优降阶算法对理论模型降阶,给出了基于最优降阶模型下纯滞后补偿控制器的离散化算法及设计步骤.现场实际应用效果表明:带有最优Smith预估算法的辊缝型监控AGC具有稳定性强、动态特性好及稳态精度高的优点.     

监控AGC系统的智能PID控制策略

为了解决带有纯滞后的监控AGC系统的控制问题,提出了基于RBF神经网络的PID控制器与Smith预估器相结合的智能PID控制系统,并对传统监控AGC、应用Smith预估器的监控AGC及应用智能PID控制的监控AGC系统进行了仿真.结果表明,应用智能PID控制的监控AGC系统收敛速度明显加快,适应能力与鲁棒性比常规PID控制要好.     

750mm热带连轧机液压厚度控制系统

介绍了某热连轧厂精轧机组液压厚度自动控制系统的硬件配置,阐述了液压伺服闭环控制系统的控制原理.针对现场实际情况,引入硬度厚度前馈AGC、变塑性系数GM-AGC、带Smith预估器的监控AGC,现场运行数据表明带钢全长的厚度极差可控制在80 μm以内.     

热连轧AGC系统的串级预测控制

在监控自动厚度控制(AGC)系统基础上,增加一个压力AGC副回路控制.基于Smith预估模型,采用串级控制方式以综合使用监控AGC与压力AGC.副回路采用PID调节方式,主回路基于广义预测控制(GPC)算法求解控制器.由于增加了副回路控制,对进入副回路的干扰有超前抑制作用,因而减少干扰对主变量的影响,提高了抗干扰能力,从而改善了过程的动态特性.仿真结果表明该方法是可行性的,具有较好的控制性能.     

单机架可逆冷轧机AGC系统的研究与应用

根据自动厚度控制的基本原理,结合单机架可逆冷轧的特点,给出了其厚度控制系统方案。分析研究了该厚度控制系统中的前馈AGC、Smith预估监控AGC、厚度计AGC和加减速厚度补偿,针对实际应用中遇到的问题,提出了具体的解决方案并在现场实施。应用结果表明,成品相对厚度精度优于±1%,满足了实际生产的要求。     

热连轧综合AGC系统的智能化控制

介绍了多机架与多种AGC控制功能的智能化协调控制,AGC调节过程中参数智能化修正以及监控AGC中模糊控制方法,并给出了实际控制效果和结论.     

冷连轧机前馈及监控AGC研究与应用

介绍了1450 mm冷连轧机前馈及监控AGC的控制策略,提出监控AGC中包含的纯滞后环节会给产品质量带来较大的影响。利用Smith预估算法解决了厚度控制纯滞后的问题,实际生产表明,厚度控制系统的精度和稳定性均有较大提高。     

可逆冷连轧监控AGC算法的研究

可逆冷连轧机系统中的监控AGC是纯滞后环节,用常规PID控制器,很难满足系统要求.利用RBF神经网络对PID控制器的参数进行自整定,在一定程度上增强了系统的鲁棒性,把基于RBF神经网络的智能PID控制器与Smith预估器相结合,对监控AGC系统进行控制,起到了很好的效果.     

全连续冷连轧机带钢厚度自动控制策略研究及实现

介绍了各种厚度控制策略在河北中钢1250mm八辊五机架全连续冷连轧机组中的应用。针对SI监控AGC的大滞后问题，提出了采用改进后的Smith预估控制算法，并通过Matlab仿真和现场运行证明此算法有较好的鲁棒性。在实际轧制过程中，各种AGC的综合应用实现了带钢厚度的精确控制，现场运行取得了良好的效果。     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.     

Quality of life of relatives of mental patients

Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined.