旅客列车线路选择的蚁群算法求解

高速铁路建成后客运通道内的线路组成要素及线路功能将发生较大变化,旅客列车在通道内的线路选择方案也需要进一步优化。采用蚁群算法（ACO）对旅客列车的线路选择进行了设计,给出了转移概率及信息量更新方法,并采用对每个蚁群单独寻优的思路,制定了相应的求解策略。经过实例验证,取得了较好的结果,为今后基于路网条件下的旅客列车线路选择方案决策优化提供了一种新的参考方法。     

基于恒星观测的船载雷达精度检验方法

针对传统的船载雷达精度检验方法存在诸如协调量大、不能经常进行的不足,提出了基于恒星观测的船载雷达精度检验方法。该方法以安装于船载雷达天线的星敏感器观测恒星的数据为比对基准。推导了将星敏感器光轴在J2000.0地心惯性坐标系中的指向,转换为以船载雷达三轴中心为原点的地平系中指向的公式。针对被跟踪目标在星敏感器中可见和不可见,给出了两种不同的光电偏差修正方法。外场试验结果表明,利用该方法检验雷达精度得到的结果与利用精轨卫星相比,残差小于0.3c,满足对雷达精度检验的要求。该方法不仅可实现雷达精度检验的经常性,也可提高雷达精度检验的实时性和有效性。     

基于恒星测量的船载雷达轴系误差修正参数动态标定

提出了一种动态条件下通过船载经纬仪和雷达标校电视联合测恒星,标定雷达轴系误差修正参数的数学方法,从理论上推导了相关的模型。在此基础上,通过实测数据进行了试算分析。分析结果表明:利用动态标定方法给出的船载无线电雷达轴系误差修正参数吸收了经纬仪光轴和雷达光轴之间的偏差,有效提高了雷达测角精度。     

粗糙集合理论在旋转机械故障诊断技术中的应用

粗糙集合理论基于严格的集合分析方法,通过对数据集合进行等价关系、近似空间、分类等运算,发现隐含在数据中的规律与性质,从而完成知识发现。在人工智能机器故障诊断系统中,如何获得故障诊断等知识成为关键技术。论文提出将粗糙集合理论应用于加工中心故障诊断技术,使得故障诊断技术中的知识获取瓶颈问题得以有效解决。     

Torsional mode magnetostrictive patch transducer array employing a modified planar solenoid array coil for pipe inspection

In recent investigations, the application of the transducers used in plates has been extended to pipe inspection with circumferential arrays because of the similar particle displacement patterns of some modes between plate and pipe, such as SH and torsional modes. Motivated by the configuration of magnetostrictive patch transducer (MPT), in which a planar solenoid array (PSA) coil was adopted to generate SH waves in plates, we proposed a MPTs array employing a modified planar solenoid array (MPSA) coil, i.e. MPSA coil-MPTs array, for generating and receiving the torsional mode in pipes. The configuration of the MPSA coil modified from PSA coil is suitable to be arranged on the pipe surface and can generate high-power waves. In the suggested configuration of MPT, because the direction of the actuating dynamic magnetic field produced by the MPSA coil is orthogonal to the direction of the static magnetic field produced by the permanent magnets in the magnetostrictive patch, the shear deformation induced by the magnetostriction in the patch will be delivered to the pipe, thus generating the torsional mode. First, it was experimentally verified that the fundamental torsional mode, T(0,1), could be effectively generated and received in pipes with the developed MPSA coil-MPTs array. Then, we studied the relationship between the frequency response characteristic of the developed MPSA coil-MPTs array and the interval defined by the distance of adjacent solenoids in the MPSA coil. Simultaneously, the circumferential crack defects in pipe were successfully identified. Finally, the performance of the MPSA coil-MPTs array was compared with that of previous meander coil-MPTs array. The comparison results demonstrated that the developed MPSA coil-MPTs array could enhance the power of the torsional mode.     

Factors determining gasoline soot abatement over CeO2–ZrO2-MnOx catalysts under low oxygen concentration condition

Soot oxidation under a low concentration O₂ (0.5% O₂/N₂) was investigated using CeO₂–ZrO₂-MnO_x mixed oxides with varied amounts of MnO_x, in order to gain low temperature catalytic activity and find out the main factors affecting the soot oxidation. The catalytic activity was remarkably improved over these catalysts compared to that of non-catalyst in such a low concentration of O₂. In particular, CeO₂–ZrO₂-MnO_x with 10% MnO_x doping (M10-CZ) showed the highest catalytic activity with its T₅₀ values of 340 °C under tight contact condition. The results of N₂ adsorption-desorption and X-ray diffraction (XRD) indicated that the textural and structural properties were not positive correlation with soot oxidation, are not the main factors affecting the catalytic activity of CeO₂–ZrO₂ and CeO₂–ZrO₂-MnO_x catalysts. The results of oxygen storage capacity (OSC), hydrogen-temperature programmed reduction (H₂-TPR), O₂ temperature program desorption (O₂-TPD), UV Raman spectroscopy (UV Raman) and X-ray photoelectron spectroscopy (XPS) testified that redox ability, oxygen storage capacity, oxygen desorption capacity at low temperature and surface active oxygen species are more important for soot oxidation. The enhancements of the catalytic behavior after MnO_x addition can be due to the improving of the adsorbed, activation and mobility of reactive oxygen species. In this work, these factors about generation and movement of reactive oxygen species are crucial for soot oxidation in a low oxygen concentration condition.     

采煤机关键部件故障分析与诊断

涡流脉冲热像（Eddy current pulsed thermography,ECPT）技术是一种新型的无损检测方法,广泛应用于金属材料结构的检测,但该技术常依赖人工经验提取特征进行裂纹检测与识别,自动化和智能性化程度不足。结合涡流脉冲热像技术以及循环神经网络（Recurrent Neural Network,RNN）的特性,提出一种基于双向长短期记忆网络（Bidirectional Long Short-Term Memory Network,Bi-LSTM）金属疲劳裂纹涡流脉冲热像分类识别方法。实验通过涡流加热装置对被测金属试件进行感应加热,使用红外热像采集装置对金属平板试件进行实时的数据采集,获得图像序列并制作数据集。运用设计的Bi-LSTM模型增强特征向量中的时序信息,对不同尺寸裂纹的热图像进行训练并测试。实验分析表明,Bi-LSTM网络可有效应用于金属疲劳裂纹检测与识别,针对现有裂纹检测准确率可达到100%,优于传统神经网络和其他深度学习的模型,具有更高的识别精度。     

零碳及碳中和燃料内燃机应用进展

通过一台改进的单缸轻型柴油机,研究3种进气压力(120、150和180 kPa)下燃料的滞燃期、十六烷值与进气压力的耦合对柴油机碳氢化合物(HC)排放的影响。使用纯柴油(B00)、B20燃料(按质量分数混合20%正丁醇和80%纯柴油的燃料)和B20+EHN (B20中添加0.7%质量分数的2-乙基己基硝酸盐)作为燃料进行实验研究。对B00和B20+EHN的碳氢排放进行比较,可知在进气氧浓度高于13%时,HC排放差值几乎不随进气氧浓度发生变化,不同压力的HC排放差异基本维持在 0~1 g/(kw·h)范围内。对B20和B20+EHN的碳氢排放进行比较,可知在 120、150 和 180 kPa 的入口压力下,临界氧浓度分别为 16%、15%和 13%,缸内燃烧温度和燃烧持续期是影响两种燃料HC排放差异的主要因素,当进气氧浓度值低于各进气压力下的临界点时,不同的十六烷值引起的缸内燃烧温度差异加大了HC 排放的差异,随着氧浓度的降低,缸内燃烧温度的影响程度增大。

     

基于国产FPGA及DAC的任意波形发生器的设计

任意波形发生器作为测试测量设备的一种重要仪器,在航空航天的测量与控制技术领域中得到了广泛应用;当前市场成熟任意波形发生器产品多为国外产品或者国内厂商基于国外FPGA和DAC研制的产品;为了打破技术垄断,提高国产任意波形发生器的自主技术保障能力,研制基于国产芯片的任意波形发生器愈发重要;随着国产芯片设计技术提升,国产FPGA和DAC的性能显著提高,并得到了广泛应用;PXI总线作为当前仪器领域的主要总线类型之一,可以满足大部分测试仪器的通讯要求;基于国产FPGA和DAC器件,从硬件设计和软件设计两个方面出发,成功研制了一款采样率为100 MSa/s的 PXI总线任意波形发生器模块,实现了43 MHz信号输出,通过实验测试了模块的功能和性能,完全满足模块指标要求,充分证明了国产芯片在工程设计中的性能特性。     

Investigation into the flow behavior of high-temperature ash and low-temperature ash of high calcium coal

The flow behavior of high-temperature ash (HTA) and low-temperature ash (LTA) of high calcium coal in the heating process was investigated systematically. By means of the heating stage microscope, the behavioral changes of samples were studied visually. The composition and mineral matters transformations of HTA and LTA samples were analyzed by X-ray fluorescence and X-ray diffraction. The results show that the original composition of HTA sample is different from that of LTA sample. In addition, the HTA and LTA samples experience the shrinkage, fusion and spreading processes in succession. However, the volume change of HTA sample is different from that of LTA sample. The volume of LTA sample shows a slow change at the temperature lower than 800 °C, while the volume of HTA sample is unchanged. In the temperature range of 800°C–1100 °C, the remarkable shrinkage of HTA and LTA samples are demonstrated. The formation of srebrodolskite and gehlenite attributes to this volume change. Moreover, the sharp shrinkage of HTA and LTA samples is indicated at 1100°C–1300 °C. This is caused by the formation of eutectics. Because of the diverse content and species of mineral matters in LTA sample, the volume change of LTA sample is more remarkable than that of HTA sample. The maximal shrinkages of LTA and HTA sample are 57% and 53%, respectively.