摘要：Crickets, similar to some other insects, have highly sensitive filiform hairs on their cerci that can detect miniscule changes in airflow. This study imitates the perception mechanism of these filiform sensory hairs of crickets by designing and fabricating a Multi-electrode Metal Core Piezoelectric Fiber （MMPF）-based airflow sensor. Four longitudinal conductive sheets were coated symmetrically on their surfaces with Metal-core Piezoceramic Fibers （MPF）. The four fan-shaped piezoelectric ceramics with surface electrode covers were polarized. After successful polarization, the cantilevered MMPF could be used as an airflow sensor. The four electrodes on the surface were symmetrically divided into two groups. Therefore, two signals can be produced by a single fiber sensor. The theoretical model of an MMPF airflow sensor has been established. The model indicates that the ratio of the two signals is equivalent to the tangent of the airflow angle. Furthermore, the sum of the squares of the two signals is not dependent on the angle, but reflects the velocity of the airflow. Therefore, a single MMPF can be used to measure both the direction and amplitude for a given airflow. The theoretical model has been confirmed via experimental measurements.

摘要：飞机使用数据的关键结构载荷预测对飞机的损伤分析和寿命预测具有重要的作用,可以为实现飞机的主动视情维修提供技术支撑。采用机器学习方法中的前馈神经网络建立大型运输机尾翼根部剪力、弯矩、扭矩载荷模型,与有限元模型计算的载荷进行对比,并且将前馈神经网络的预测结果与随机森林方法和多元线性回归方法的预测结果进行对比和分析。结果表明:前馈神经网络的预测结果的相对误差满足工程要求,前馈神经网络的预测精度优于随机森林方法和多元线性回归方法,为构建基于数据驱动的飞机结构损伤分析和寿命评估体系提供了重要的技术支持。

摘要：The piano teaching in the music education in normal universities can promote the students to feel the music, and improve the students＇ music qualities. The students can get the sense of the rhythm, the sense of harmony and the sense of pitch and other musical skills in the process of learning to play the piano, thus more accurate performing the music art. For the purpose, the piano teaching in the music education in the normal universities is for the purpose of cultivating the future piano teachers or performers. In this paper, the author carries out thediscussion with the dual nature of the piano teaching in the music education in normal colleges as the theme, in order to put forward some useful strategies for the piano teaching in eoUeges and universities.

摘要：页岩储层具有低孔、低渗、难动用等特点，通常采用长水平井和大规模体积压裂组合技术进行开发。压裂液进入地层后与储层发生一系列物理-化学反应，其中盐离子扩散作用显著，但针对离子扩散机理及其诊断压裂缝网作用的现有研究尚不完善。采用理论分析和现场案例相结合的方法总结了页岩储层中盐离子来源、离子扩散特征、机理及影响因素，给出了基于盐离子扩散机理诊断压裂缝网的实例。页岩储层盐离子来源包括储层孔隙壁面水膜中的溶解盐、生烃排水时的结晶盐、水-岩相互作用的产出盐。离子扩散特征与渗吸过程相似，分为扩散初期、过渡期、后期三个阶段；其中初期离子扩散速率较高，对数时间尺度上呈线性关系，遵循Fick定律和Einstein-Smoluchowski方程；影响盐离子扩散的因素包括储层性质、溶液性质、温度、黏度等；盐离子扩散可用于体积压裂缝网发育程度诊断。盐离子扩散诊断压裂缝网发育程度的方法可为页岩储层压裂设计和缝网评估提供科学指导，有助于实现更加精准和有效的储层改造，推动页岩油气资源的高效开发和利用。

摘要：为了提升小米椒的机械化收获质量和效率,对小米椒的物理及力学特性进行了试验测量。通过测量,小米椒在15天内的含水率为86%~90%,且中部最高、首部次之、尾部最低。通过拉伸试验,确定小米椒断裂时的抗拉强度为0.679 MPa±0.03 MPa。采用正交旋转组合设计方法,确定了加载速度对抗压强度的影响极显著,小米椒直径对抗压强度的影响显著,加载速度对剪切强度的影响显著。通过轴向压缩和剪切试验,确定了小米椒首部的抗压强度平均值为0.62 MPa,弹性模量平均值为2.72 MPa;中部抗压强度平均值为0.64 MPa,弹性模量平均值为3.17 MPa;尾部抗压强度平均值为0.61 MPa,弹性模量平均值为2.64 MPa,小米椒剪切强度平均值为0.32 MPa。

摘要：设计、分析、制作了一种工作在Ka波段的4单元高增益、圆极化机载微带天线阵列。利用顺序旋转阵列和串并馈方式的微带线网络馈电,显著改善了天线的轴比带宽和驻波带宽,减少了馈线损耗,实现了高增益。采用L型微带调配枝节对贴片单元进行匹配,便于组阵,解决了阵列空间布局不合理的难题;馈电网络和天线单元集成在同一介质基板上,易于加工和制作。测试结果表明:该天线阵具有高增益和良好的圆极化特性,从而证实了该方法的正确性和实用性。本文所设计的天线由于具有体积小、质量轻、结构紧凑、易于集成等优点,在机载相控阵雷达以及卫星通信系统中具有很好的应用前景。

摘要：With large-scale use of kinds of motors, oilfield drilling electrical system always accompanied by serious power quality problem, including reactive current, harmonics current and grid voltage distortion, which would greatly threaten the safety and proper working of the whole system. This paper focuses on a power quality improvement project to solve these problems. A hybrid compensating scheme, including an active compensator and a passive compensator, is carried out. Because of the specificity of oilfield drilling electrical system, compensators are redesigned against features of this application background. And then the current detection point arrangement of this hybrid system is also taken into consideration to build the whole system much more effective and reliable. Now the improvement project is already implemented in application field, and the power quality of the system is greatly improved.

摘要：提出了一种新型的适合于电小天线匹配的网络拓扑结构并成功地进行了验证.采用了实频数据法和直接优化法相结合的优化方法来设计电小天线的宽带匹配网络.从电小天线的特性出发,分别采用全段匹配和分段匹配的方法设计其网络拓扑结构,利用算法的寻优特性针对电小天线进行宽带匹配设计,显著提高了电小天线的使用效率和性能,并且利用仿真软件进行了计算和验证,最后对这两种方法进行了比对.设计结果表明：经过优化设计后,该电小天线的电压驻波比在100~180 MHz内小于2.5且其效率基本上大于30%.所提出的网络拓扑结构非常适用于电小天线的宽带匹配,在设计电小天线以及其它天线的宽带匹配网络上具有很大的应用前景.

摘要：清洁、抽速稳定的高真空系统是氢脉泽工作必不可少的组成部分之一。文章详细介绍了双真空主动型氢脉泽真空系统的组成及各个组成部分的设计思路、方法。内容涉及真空的获得、真空泵的选择、氢脉泽物理部分双真空系统设计、流导及抽速的计算、泵体结构的设计和实验验证。实验发现,设计完毕的氢脉泽双真空系统保温效果较以前大幅改善,内外真空室本底流量为0.1 mA,工作流量值稳定在0.7mA时氢脉泽稳定输出-105 dBm信号,关闭流量后内真空抽真空本底时间约为8 min。表明内外真空室离子泵均达预期设计指标且工作正常。此外,该设计还进一步减小了脉泽体积、减轻了其重量,向氢脉泽小型化迈出了坚实一步。

摘要：艺术类大学生的思想政治教育就其对象的特殊性,其组织和开展的资源、条件及人文价值也具有一定的特殊性,关注艺术类大学生思想政治教育资源的挖掘,在当前高校思想政治教育活动中具有独特的现实意义与人文价值。