利用粉煤灰等工业废料制备日用陶瓷的研究

针对目前火电厂大量排放粉煤灰,陶瓷工业产生大量废匣钵、废瓷粉但得不到充分利用的现象,为了使其变废为宝,本实验在长城陶瓷有限公司成熟的注浆泥配方的基础上,利用正交实验设计配方,经调整配方组成,加入了粉煤灰等工业废料,现己研制出清洁生产日用陶瓷的配方。其中粉煤灰、废匣钵、废瓷粉的含量分别是10%,10%,8%,工业废料的含量合计达到了28%。由于粉煤灰、废瓷粉和废匣钵的价格低廉,应用此技术则可以为企业带来可观的经济效益。     

2016唐山世园会志愿者英语服务能力提升策略研究

研究通过对2016唐山世界园艺博览会志愿者英语服务能力需求与唐山市现有志愿者英语服务能力培训现存问题的调查和分析,提出世园会志愿者英语服务能力提升策略与途径。     

响应面法优化碱催化酯交换反应制备生物柴油工艺研究

根据中心组合试验设计原理，通过30个试验，其中有6个样本的中心点，以甲酯含量作为响应值。考察反应时间、催化剂用量、反应温度和醇油摩尔比对碱催化酯交换反应的影响，确定碱催化酯交换反应制备生物柴油的二阶多项式模型。试验结果很好地拟合模型及对99％以上的差异做了解释，优化工艺参数的反应时间为45min、催化剂用量为1．5％、反应温度50℃、醇油摩尔比为7．5，试验值在95％的置信区间符合预测值。结果表明，RSM优化的模型适合于碱催化酯交换反应制备生物柴油工艺，能够预测不同条件下碱催化酯交换反应得到甲酯含量。     

Synthesis and characterization of Bi2S3 nanorods by solvothermal method in polyol media

Bi₂S₃ nanorods were synthesized via a simple solvothermal process in polyol media through the reaction between Bi(NO₃)₃·5H₂O, urea and CS₂ at 150 °C for 15 h using diethylene glycol as solvent. The nanorods were characterized by XRD, TEM and SAED. The results showed that the products were well-crystallized orthorhombic phase with lattice parameters a = 11.15 Å, b = 11.3 Å and c = 3.984 Å, which are consistent with the value in standard JCPDS card No. 17-0320. DEG served as an excellent solvent and structure director. Besides, compared to water and EG as solvents, the DEG system can provide a mild and homogenous condition, which is favorable to anisotropic growth and increases the yield of high quality Bi₂S₃ nanorods. Based on the experimental results, the growth mechanism was discussed.     

Transmembrane segments prediction and understanding using support vector machine and decision tree

In recent years, there have been many studies focusing on improving the accuracy of prediction of transmembrane segments, and many significant results have been achieved. In spite of these considerable results, the existing methods lack the ability to explain the process of how a learning result is reached and why a prediction decision is made. The explanation of a decision made is important for the acceptance of machine learning technology in bioinformatics applications such as protein structure prediction. While support vector machines (SVM) have shown strong generalization ability in a number of application areas, including protein structure prediction, they are black box models and hard to understand. On the other hand, decision trees provide insightful interpretation, however, they have lower prediction accuracy. In this paper, we present an innovative approach to rule generation for understanding prediction of transmembrane segments by integrating the merits of both SVMs and decision trees. This approach combines SVMs with decision trees into a new algorithm called SVM_DT. The results of the experiments for prediction of transmembrane segments on 165 low-resolution test data set show that not only the comprehensibility of SVM_DT is much better than that of SVMs, but also that the test accuracy of these rules is high as well. Rules with confidence values over 90% have an average prediction accuracy of 93.4%. We also found that confidence and prediction accuracy values of the rules generated by SVM_DT are quite consistent. We believe that SVM_DT can be used not only for transmembrane segments prediction, but also for understanding the prediction. The prediction and its interpretation obtained can be used for guiding biological experiments.     

基于变精度粗糙集的柴油机监测点优化

为获得有效的柴油机振动信号监测点,提出了一种基于变精度粗糙集模型的测点优化方法。该方法在保证集合相对可辨别性的前提下,计算各个测点的阈值,并以此作为测点优劣的评判标准。以某大功率柴油机为例,采集不同测点位置的振动信号,并提取频域特征值;应用基于变精度粗糙集的方法进行测点的优化计算,与实验结果进行对比,表明该方法能够有效区分不同测点位置以及不同故障类型的敏感程度,从而得到效果较好的振动信号监测点位置,同时减小噪声对故障诊断的影响,有利于提高故障诊断的准确率和效率。     

斜巷运输跑车防护系统自动化研究

研究了矿井斜巷运输中的跑车防护系统,设计了一种跑车防护系统。采用破坏矿车平衡以及吸能的原理,达到跑车防护的目的。该系统处理事故时间短,操作简单,可远程操作。     

滚动工况下钢质车轮和铝合金车轮的有限元分析对比

根据车轮的结构和实际工作条件,采用ANSYS有限元分析技术,建立1/16车轮的模型。计算了滚动工况下钢质车轮、铝合金车轮在不同转速下的应力值和变形值。通过对比分析计算结果,得出的结论可为铝合金车轮的设计提供依据,最后作试验验证了所建模型的合理性。     

基于Autogram的齿轮断齿故障特征提取方法

针对复杂生产背景下产生的强噪声淹没齿轮有效故障特征信息的问题,利用Autogram方法对其进行特征提取。该方法利用最大重叠离散小波包变换,对齿轮断齿故障振动信号进行不同层数分解处理,每层得到若干个信号,被称为“node”。为了更加全面地描述故障特征信息,对每个node进行包络谱的3种无偏自相关谱峭度求取,以便选取合适node作为信号源进行下一步分析。最后,对该信号源引入阈值处理,以便加强频谱分析的全面性,实现对齿轮断齿故障特征信息的有效提取。通过对比分析仿真和实测齿轮故障振动信号,验证了该方法的有效性。     

基于EKF的PMSM无传感器检测技术仿真研究

在永磁同步电动机(PMSM)的速度控制中,其位置和速度的精度、实时性受到传感器精度的限制。文章在对永磁同步电动机在α-β坐标系下的非线性数学模型进行线性化的基础上,应用扩展卡尔曼滤波器(EKF)来替代电机的角位置与速度传感器,最后通过Matlab/Simulink.仿真平台建立了基于EKF状态估计器的无传感器矢量控制系统。仿真结果表明所提出的控制方法无论在PMSM空载和负载时,均保持较好的跟踪性能,具有良好的转子位置和转速在线估算能力。