The Combined Method of Ray Tracing and Diffraction and Its Application to Ultra-wideband Pulse Propagation

Wireless Personal Communications - A robust recursive least square (RRLS) algorithm that has been designed for SISO communications by Bhotto and Antoniou (IEEE Signal Process Lett...     

Influence of force load on the stability of ultrasonic longitudinal–torsional composite drilling system

This study aimed to investigate the problems of system detuning, amplitude attenuation, and even vibration stop after the load was applied to the acoustic system during ultrasonic-assisted vibration processing. In the theoretical part, the overall theoretical model of the ultrasonic longitudinal–torsional composite drilling system (ULTCDS), including the longitudinal–torsional composite horn, transducer, and load was established based on the four-terminal network, combined with the longitudinal and torsional vibration equations of the variable cross-section rod. Also, the influence of the load on the input impedance and output amplitude of the acoustic system was preliminarily analyzed. In the simulation part, the static and dynamic drilling force was simulated by the pre-stressed modal and transient dynamic analyses, and the influence of the force load on the resonant frequency and output amplitude of the system was further explored. In the experiment part, the static force loading test and the ultrasonic drilling test of titanium alloy were designed. The micro-morphology of drilling holes under different processing parameters was observed, and the influence of force load on the system characteristics and stability was explored. The results showed that when the system was subjected to a force load greater than 400 N, the system current and frequency were greatly offset, the electromechanical conversion efficiency reduced, and the amplitude was attenuated to below the amplitude at empty load. In the ultrasonic-assisted drilling of titanium alloy processing, the acoustic system undergoes an obvious detuning phenomenon and the drilling quality is attenuated when the current increased by more than 60% and the frequency changed by more than 350 Hz, affecting the stability of the system and the ultrasonic-assisted processing effect.     

Using travel socialization and underlying motivations to better understand motorcycle usage in Taiwan

This study introduces self-determination theory (SDT) to refine previous models of vehicle usage motivation. We add travel socialization theory regarding parental influence on vehicle usage to enhance previous structural models describing motorcycle usage behavior. Our newly developed model was empirically verified in a sample of 721 motorcycle users in Taiwan. In addition to instrumental, symbolic, and affective motivations, perceived parental attitudes (PPAs) towards motorcycle riding were found to have a significant effect on individuals’ motorcycle use habits. Additionally, participants who perceived their parents to have more positive attitudes toward motorcycles were found to have more experience being chauffeured on motorcycles by their parents. Based on these results, we suggest means to confront the challenges brought on by the rapid growth of motorcycle usage, especially serious motorcycle traffic accidents. These results improve our understanding motorcycle usage in Taiwan and can be used by transportation professionals who are seeking solutions to the rapid growth of motorcycle usage.     

125I粒子条联合胆道支架植入治疗恶性梗阻性黄疸22例疗效分析

【摘要】　 　目的 研究和探讨125I粒子条联合胆道支架植入治疗恶性梗阻性黄疸的临床疗效。方法 2011年6月—2013年9月收治恶性梗阻性黄疸患者40例。行胆道支架植入术治疗患者18例，为对照组；采用125I粒子条联合胆道支架植入患者22例，为观察组。两组均采用经皮肝穿刺胆道引流（PTCD）并胆道支架植入。结果 观察组与对照组的平均胆道开通时间分别为（8.7 ± 0.7）和（6.2 ± 0.4）个月，两组比较差异有统计学意义（P < 0.05）。观察组与对照组术后平均生存时间分别为（11.4 ± 0.8）和（8.7 ± 0.5）个月，生存时间的差异有统计学意义（P < 0.05）。术后近期疗效及并发症两组之间的比较无明显差异（P > 0.05），但是远期疗效有显著差异（P < 0.05）。结论 与对照组相比，观察组的术后生存时间及胆道开通时间明显延长，对于125I粒子条联合支架治疗恶性梗阻性黄疸值得进一步临床研究。