Blind source separation based vibration mode identification

In this paper, a novel method for linear normal mode (LNM) identification based on blind source separation (BSS) is introduced. Modal coordinates are considered as a specific case of sources that have certain time structure. This structure makes modal coordinates identifiable by many BSS algorithms. However, algorithms based on second-order statistics are particularly suited for extracting LNMs of a vibration system. Two well-known BSS algorithms are considered. First, algorithm for multiple unknown signals extraction (AMUSE) is used to illustrate the similarity with Ibrahim time domain (ITD) modal identification method. Second, second order blind identification (SOBI) is used to demonstrate noise robustness of BSS-based mode shape extraction. Numerical simulations and experimental results from these BSS algorithms and ITD method are presented.     

气象仪器巡检数据智能采集管理系统的设计与研究

在梳理中国现有的地面气象设备监控工作的基础上,针对现有对气象仪器状态的巡检方式仍为人力采集,采集效率低下和难以管理的问题,设计地面气象观测设备运行状态监测方案,研发针对仪器巡检的智能采集管理系统,推动现存气象设备巡检的电子化与智能化发展进程,促进中国气象巡检数据智能采集管理技术的发展,保障巡检工作的规范化、标准化.该巡检数据智能采集管理系统贴合气象装备保障业务实际需求,经投入气象站运行,稳定可靠,能对设备进行全方位监控,减少了气象部门人力资源投资,大幅度提高工作效率.     

球铁实用冒口及浇口的设计计算

就球铁实用冒口及浇注系统设计问题,在现有文献资料的基础上进行了新的组合,并对一些实用图线进行了密切相关的数学拟合处理,对球铁实用冒口及浇口设计拟定了明确的设计步骤与计算方法,从而使设计工作做到步骤化与公式化,为这一技术的进一步普及推广提供方便。文中求得的计算公式,也可为计算机辅助工艺设计提供数学模型上的参考。     

面向外汇市场监测的分布式计算框架设计

针对金融外汇市场监测指标计算复杂度高、完备性强、效率低等问题,基于Spark大数据架构提出了一种新的面向外汇市场监测的分布式计算框架。首先,对外汇市场监测的业务特性和现有技术框架进行了分析总结;然后,综合考虑了外汇单市场多指标和多市场多指标并行计算的业务特性;最后,基于Spark的有向无环图（DAG）作业调度机制和YARN的资源调度池隔离机制,分别提出了外汇市场级的有向无环图（M-DAG）模型和市场级资源分配策略——M-YARN。实验结果表明,所提面向外汇市场监测的分布式计算框架相对于传统技术框架在性能上提高了80%以上,可以有效保证大数据背景下外汇市场监测指标计算的完备性、精准性和时效性。     

BaTiO3薄膜纳米发电机平衡压电势的理论研究

利用薄膜-衬底系统二参量模型,研究了单层钛酸钡(BaTiO3)压电纳米薄膜系统在轴向应力下发生的弯曲.分析讨论了BaTiO3纳米薄膜的极化强度、极化电荷量及压电电势分布.根据力学平衡法求解出弯曲BaTiO3薄膜压电势以及薄膜弯曲曲率半径和薄膜内应变.结果表明,本工作的理论模型计算的结果与Park等报道的实验及有限元模拟结果非常符合,给出了压电纳米薄膜发电机机理的简单模型和理论基础.     

Finite element analysis of effect of interfacial bubbles on performance of epoxy coatings under alternating hydrostatic pressure

The stresses around bubbles formed on a coating/substrate interface under hydrostatic pressure(HP)and alternating hydrostatic pressure(AHP)were calculated using the finite element method.The results reveal that HP promotes coating failure but does not mechanically destroy the interface,whereas AHP can provide tensile stress on bubbles formed at the interface and accelerate disbonding of the coating.Because of water resistance,a lag time exists for the coating that serves in an AHP environment.The coating can have a better protective performance if the lag time suits the AHP to minimize the impact of the AHP on the interface.     

Cosensitized Quantum Dot Solar Cells with Conversion Efficiency over 12%

The improvement of sunlight utilization is a fundamental approach for the construction of high‐efficiency quantum‐dot‐based solar cells (QDSCs). To boost light harvesting, cosensitized photoanodes are fabricated in this work by a sequential deposition of presynthesized Zn–Cu–In–Se (ZCISe) and CdSe quantum dots (QDs) on mesoporous TiO₂ films via the control of the interactions between QDs and TiO₂ films using 3‐mercaptopropionic acid bifunctional linkers. By the synergistic effect of ZCISe‐alloyed QDs with a wide light absorption range and CdSe QDs with a high extinction coefficient, the incident photon‐to‐electron conversion efficiency is significantly improved over single QD‐based QDSCs. It is found that the performance of cosensitized photoanodes can be optimized by adjusting the size of CdSe QDs introduced. In combination with titanium mesh supported mesoporous carbon as a counterelectrode and a modified polysulfide solution as an electrolyte, a champion power conversion efficiency up to 12.75% (V_oc = 0.752 V, J_sc = 27.39 mA cm^?2, FF = 0.619) is achieved, which is, as far as it is known, the highest efficiency for liquid‐junction QD‐based solar cells reported.