GAS-LIQUID EQUILIBRIUM OF Pb-Cd-Zn SYSTEM UNDER VACUUM

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Effects of secondary carbide precipitation and transformation on abrasion resistance of the 16Cr-1Mo-1Cu white iron

The relationship between secondary carbide precipitation and transformation of the 16Cr-1Mo-1Cu white iron and abrasion resistance were investigated. The results show that secondary carbide precipitation and transformation at holding stage play an important role in the hardness and abrasion resistance. After being held for a certain time at 853 K for subcritical treatment, the grainy secondary carbide, (Fe,Cr)₂₃C₆, precipitated first and then Fe₂MoC or MoC carbides precipitated in the alloy, both of which improve the bulk hardness and abrasion resistance of the alloy. The reasons for these improvements are the secondary carbide precipitates from the austenite and the retained austenite transforms into the martensite, both make the matrix strengthen. So the matrix has more effective support to the harder eutectic carbide against exterior abrasion. With expanding the holding time, the in situ transformation from the granular (Fe,Cr)₂₃C₆ carbide into laminar M₃C carbide causes the formation of the pearlitic matrix and an associated decrease of the alloy abrasion resistance.     

钢管热处理过程的“黑匣子”动态温度测试

钢管在热处理炉内的实际升温数据是准确制定热处理工艺必需的参数。常规热处理温度测试采用如热电偶、红外温度计等,但测试结果都与实际温度存在较大偏差。“黑匣子”温度测试仪相对来说测温偏差最小。介绍了耐高温“黑匣子”测试技术在钢管连续热处理炉上的应用。通过对热处理过程的数字化,分析了“黑匣子”温度测试在热处理工艺改进和优化方面的应用情况。     

事件常识的获取方法研究

在动态语义学的基础上,以事件的语义、文法和常识为标准构建多层次的事件分类体系,并使用该分类体系提取事件的常识知识。事件采用框架的方式来表示,称为事件框架。事件框架的内容包括事件的定义、事件之间的关系、事件的文法表达、事件的谓词表示、事件的例句、事件的前提常识和后果常识。利用事件框架的内容提取事件的常识。为了说明该方法的实用性,以事件分类体系中典型的“交易类”事件为例来描述事件常识的获取方法。     

Adaptive Fuzzy PD+ Control for Attitude Maneuver of Rigid Spacecraft

In this paper, an adaptive fuzzy PD+ controller is proposed for the attitude maneuver of rigid spacecraft. The novel controller adjusts the gains of the PD+ attitude controller online according to attitude errors and angular velocity errors during the maneuver procedure. Therefore, quick response and avoidance of actuator saturation can be achieved simultaneously. Furthermore, the adaptation mechanism is designed, based on Lyapunov theory, to guarantee the stability of the closed‐loop system. To achieve good performance of the closed‐loop system under the constraint of actuator saturation, controller parameter optimization is developed on the basis of a genetic algorithm. Simulation results show that the transient performance and robustness against parametric uncertainty and environmental disturbance of the adaptive fuzzy PD+ controller are better than those of a constant PD+ controller.     

薄壁不锈钢管波纹卡粘式连接方法及性能研究

介绍了薄壁不锈钢管波纹卡粘式连接的原理、安装方法、注意事项以及工程应用情况,试验研究了波纹卡粘式连接件的连接强度、密封性、使用寿命等。结果表明:经完全固化后,波纹卡粘式连接件的最大破坏扭矩达到41N·m,接近于DN15薄壁不锈钢管产生塑性变形时的扭矩强度;连接密封性能相关的8项指标全部符合国标要求。在550℃的高温炉内,连接件的泄漏量为0.02m3/h,远小于规定的0.17m3/h。根据阿累尼乌斯图推算出连接件的使用寿命可达70a以上。卫生检测显示连接件中的厌氧胶不会影响水质,清洁卫生。     

克隆选择算法及其在汽油辛烷值预测中的应用

辛烷值是汽油品牌划分和汽油抗爆特征划分的重要参数,传统实验室分析方法具有费用高、操作复杂、操作时间长等问题。针对传统方法面临的诸多问题,该文在近红外光谱分析分析的基础上,采用基于克隆选择方法优化的SVM预测汽油辛烷值。仿真结果表明,该方法操作简单,预测准确,为汽油辛烷值预测提供了一种新的方法。     

Informative conditions for a data set in a MIMO closed‐loop system with a switching controller

In system identification, a data set needs to be informativeto ensure that the identification criterion has a unique global minimum asymptotically, and the parameter estimation is consistent. To guarantee a data set in a MIMO closed‐loop system with a switching controller to be informative, we develop a group of flexible conditions for the controller's switching rule and feedback laws, which provide a trade‐off between these two aspects through adjustable parameters. Compared with the results in the existing literature, our result includes all kinds of switching rules and therefore is not limited by the constraints on the switching rule.Copyright © 2014 John Wiley & Sons, Ltd.     

微电流电解对尿素降解的机理及影响因素研究

采用微电流电解技术对模拟游泳池水中的尿素进行降解处理,探索了电解对尿素的去除机理,研究了电流密度和氯离子浓度等因素对电解去除尿素效果的影响。结果表明:以钌钛和不锈钢分别做阳极和阴极材料,当水溶液中有较高浓度的氯离子存在时,电解过程中产生的活性氯使得尿素被氧化,尿素降解产物中无氨氮、氯胺等二次污染物,尿素极有可能通过电解生成了N2等气体挥发到空气中。电流密度和氯离子浓度对尿素的去除效率有很大影响,随着电流密度和氯离子浓度的增加,尿素去除效率逐渐上升。在500 mg/L的氯离子浓度条件下,电流密度为12 m A/cm2时,电解处理30 min时尿素去除率可达99.5%。将微电流电解技术应用于游泳池水中的尿素去除,无需添加电解质,即能达到较高的尿素去除效果,采用该技术对游泳池水中的尿素进行降解去除完全可行。