双谐振点发动机推力矢量控制伺服机构算法优化研究

建立运载火箭双谐振点发动机的双质量弹簧物理模型,辨识特性参数,推导出伺服机构数学模型。采用直接数值寻优方法对推力矢量控制伺服机构算法进行计算优化研究,通过仿真分析和发动机冷摆试车试验,得出双陷波补偿是一种较优选择。     

水解条件对聚天冬氨酸高吸水性树脂的性能影响

以中间体聚琥珀酰亚胺(PSI)为原料,己二胺为交联剂,通过在乙醇和水的混合介质中水解,合成了环境友好型的聚天冬氨酸高吸水性树脂。研究了乙醇和水的体积比对水解过程和产物性能的影响。结果表明,当乙醇和水的体积比为7∶3时,树脂分散均匀,体系无粘结,且水解产物吸水性能最好。通过正交实验考察了在最佳乙醇用量的水解介质中进行水解时,PSI相对分子质量、水解温度、体系pH值和水解时间对吸水性树脂吸水性能的影响,得到了合成高吸水性树脂的最佳工艺条件为:PSI分子量为88500、水解温度35℃、pH值9.5～10.0、水解时间4h。在此最优条件下所制备的吸水性树脂的吸水率达1021倍。对产物进行TG测试结果表明,所制备的吸水树脂具有良好的热稳定性。     

应用增广Lagrange乘子法确定裂纹应力强度因子——在RBF无网格法框架下实现

提出将增广Lagrange乘子法与RBF无网格法相结合来处理裂纹非连续性问题,从而确定裂纹应力强度因子.用径向插值基函数构造无网格形函数,基于虚裂纹扩展模式推导裂纹扩展控制方程;采用增广Lagrange乘子法处理裂纹非连续面;给出了处理裂纹非连续问题的计算列式和增广Lagrange乘子法迭代过程.通过与相关文献解比较,论证了本文方法的可靠性.     

数字技术赋能下的德化窑瓷雕技艺活化与再生研究

目的 在数字技术赋能下,对德化窑瓷雕技艺进行活化与再生,更好地对德化窑瓷雕技艺进行保护与传承。方法 以德化窑瓷雕技艺为研究对象,将德化窑瓷雕技艺与现有的数字技术手段进行结合,探讨数字技术赋能下的德化窑瓷雕技艺活化与再生的具体内容。首先厘清德化窑瓷雕技艺发展脉络及研究现状,构建研究框架;其次在分析数字化技术在德化窑瓷雕技艺中适用性的基础上,依据德化窑瓷雕技艺保护与传承的特点,有针对性地从数据采集记录、数字知识转化、数字展示传播、数字形态再生四个维度对德化窑瓷雕技艺活化与再生展开具体研究。结论 其为德化窑瓷雕技艺主体及器物客体的数字化保护活化与创新再生增加新的内涵;也为相关非物质文化遗产(特别是传统技艺类项目)的有序传承、科学保护提供理论研究借鉴。     

Strong exciton-photon interaction and lasing of two-dimensional transition metal dichalcogenide semiconductors

Nano Research - Two-dimensional (2D) transition metal dichalcogenide (TMDC) semiconductors not only hold great promises for the development of ultra-thin optoelectronic devices with low-energy...     

Study on the composite Nd：YAG crystal by laser micro- Raman spectroscopy

The composite Nd:YAG crystal with undoped YAG end caps was fabricated by thermal bonding technique. Scanning electron microscopy (SEM) result shows that the width of the bonded interface was about 0.5 μm. The laser micro-Raman was used to study the bonded interface of the composite crystal. The results of Raman spectra and the bonded interface image indicate that the undoped YAG and Nd:YAG crystals have been well bonded together. Furthermore, it can be drawn that the structure and the composition of the bonded interface are the same as the undoped YAG crystal, and that the Nd3 ions do not enter the bonded interface and the YAG side. This property is advantageous to decrease the thermal effect of the boned interface and to improve the laser stability.     

Composing photomosaic images using clustering based evolutionary programming

Multimedia Tools and Applications - Photomosaic images are a type of images consisting of various tiny images. In the past, many approaches have been proposed trying to automatically compose...     

Axisymmetric hub-endwall profile optimization for a transonic fan to improve aerodynamic performance based on an integrated design optimization method

Structural and Multidisciplinary Optimization - This paper investigates an optimization for the axisymmetric hub-endwall profile of a transonic fan designed for a civil high bypass ratio turbofan...     

基于CART的社区矫正人员危险性评估

目前对社区矫正人员危险性评估的研究普遍停留在理论研究阶段,建立的模型大多缺乏实际数据的支撑,为了方便掌握社区矫正实际情况,基于CART（分类回归树）算法对某市司法局的社区矫正人员数据（不包含敏感信息）进行建模分析,通过服刑人员的基础特征值得到该服刑人员的危险度评估结果,与实际结果相比,准确率达到85%~90%,此外对社区矫正中实际存在的数据缺失问题进行讨论并提出解决办法。