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111.
The microstructure and mechanical properties of Sn–xBi (x = 10, 20, 25, and 35) solder alloy were investigated by scanning electronic microscope and notch tensile test. The results showed that the microstructure of Sn–10Bi and Sn–20Bi solder alloy was constituted by Bi particle and β-Sn phase. The microstructure of Sn–25Bi and Sn–35Bi solder alloy was consisted of eutectic phase and primary phase. The ultimate tensile load of Sn–20Bi solder alloy was higher than that of Sn–10Bi in notch tensile test. The ultimate tensile load of Sn–25Bi and Sn–35Bi was declined gradually compared with that of Sn–20Bi solder alloy. The fracture energy of Sn–xBi was decreased continuously when the Bi fraction increased. Crack observation, fracture surface observation, and finite element analysis revealed that the crack initiation and propagation of Sn–25Bi and Sn–35Bi was dominated by the fracture of brittle eutectic phase. Therefore, the ultimate tensile load and fracture energy of Sn–25Bi and Sn–35Bi were damaged compared with that of Sn–20Bi. 相似文献
112.
本文从管理要求与技术要求两个方面指出了实验室管理体系运行中常见的问题,并结合实际情况提出了相应措施,最后对加强实验室管理体系运行有效性提出了几点建议。 相似文献
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Amar R. Marathe Jason S. Metcalfe Brent J. Lance Jamie R. Lukos David Jangraw Kuan-Ting Lai 《Theoretical Issues in Ergonomics Science》2018,19(3):283-320
ABSTRACTA primary goal for human-autonomy integration (HAI) is to balance the strengths of human and autonomy in order to achieve performance objectives more efficiently and robustly than either the human or autonomous agents would independently. This paper proposes the Privileged Sensing Framework (PSF) as a novel approach to HAI. This approach is based on the concept of dynamically ‘privileging’ information during the process of integration by dynamically bestowing special rights based on the characteristics of each individual agent, the task context, and the performance goals. The proposed framework is tested through a series of simulation experiments that provide a clear demonstration of increased accuracy and throughput of human-autonomy performance. These proof-of-concept simulations provide initial evidence of the utility of the PSF. Continued development of this approach has the potential to revolutionise capabilities of multi-agent cooperative teams across a broad range of applications. 相似文献
116.
Lai Feili Wang Yue Li Dandan Sun Xianshun Peng Juan Zhang Xiaodong Tian Yupeng Liu Tianxi 《Nano Research》2018,11(2):1099-1108
Nano Research - Benefiting from their unique delocalized electronic structure, conjugated polymer-based semiconductors are widely applied in the fields of organic electronics, sensors, and... 相似文献
117.
The commercial finite element package ABAQUS has been used to analyse the crack bridging process by Ti-15 at%V -phase particles dispersed in -TiAl matrix in the presence of particle–matrix decohesion. Both the particle–matrix decohesion potential and the -phase materials constitutive relations are found to have a major effect on the ductility, fracture toughness and failure mode of the – two-phase material. The interface potential is found to primarily affect the distribution of the normal interface strength ahead of the advancing interfacial crack and the mode (gradual versus sudden) of decohesion. The -phase materials constitutive relations are found to influence the location of nucleation of the interfacial cracks and, in turn, the mode of decohesion. A metastable -phase that can plastically deform at low stress levels by undergoing a stress-assisted martensitic transformation, but experience a high rate of strain hardening is found to give rise to the largest levels of ductility and fracture toughness is the – two-phase material. © 1998 Kluwer Academic Publishers 相似文献
118.
K. Kumagai S. Ikeda J. Jiang M. S. Lin C. C. Lai H. C. Ku 《Journal of Low Temperature Physics》1996,105(5-6):1641-1646
195Pt-,139La- and11B-NMR have been investigated in quaternary RM2B2C (R=Y, La, Th and M=Ni, Pd, Pt). The electric quadrupole frequency of139La changes more than 5 times in magnitude from M=Ni to Pt, indicating that the hybridization of La-5d and d-electrons of M-element changes largely. The analysis of11B and139La spectra shows also the large change of the magnetic anisotropy with R and M element, i.e., II c>II ab in LaNi2B2C, but II c>II ab YNi2B2C.The data of T1T and K of195Pt and11B are consistent with the band effects and with no evidence of strong antiferromagnetic correlation effects. 相似文献
119.
Machine vision represents a particularly attractive solution for sensing and detecting potential collision‐course targets due to the relatively low cost, size, weight, and power requirements of vision sensors (as opposed to radar and Traffic Alert and Collision Avoidance System). This paper describes the development and evaluation of a real‐time, vision‐based collision‐detection system suitable for fixed‐wing aerial robotics. Using two fixed‐wing unmanned aerial vehicles (UAVs) to recreate various collision‐course scenarios, we were able to capture highly realistic vision (from an onboard camera perspective) of the moments leading up to a collision. This type of image data is extremely scarce and was invaluable in evaluating the detection performance of two candidate target detection approaches. Based on the collected data, our detection approaches were able to detect targets at distances ranging from 400 to about 900 m. These distances (with some assumptions about closing speeds and aircraft trajectories) translate to an advance warning of between 8 and 10 s ahead of impact, which approaches the 12.5‐s response time recommended for human pilots. We overcame the challenge of achieving real‐time computational speeds by exploiting the parallel processing architectures of graphics processing units (GPUs) found on commercial‐off‐the‐shelf graphics devices. Our chosen GPU device suitable for integration onto UAV platforms can be expected to handle real‐time processing of 1,024 × 768 pixel image frames at a rate of approximately 30 Hz. Flight trials using manned Cessna aircraft in which all processing is performed onboard will be conducted in the near future, followed by further experiments with fully autonomous UAV platforms. © 2010 Wiley Periodicals, Inc. 相似文献
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