A transient 3D model was established to investigate the effect of spatial interaction of ultrasounds on the dual-frequency ultrasonic field in magnesium alloy melt.The effects of insertion depth and tip shape of the u...A transient 3D model was established to investigate the effect of spatial interaction of ultrasounds on the dual-frequency ultrasonic field in magnesium alloy melt.The effects of insertion depth and tip shape of the ultrasonic rods,input pressures and their ratio on the acoustic field distribution were discussed in detail.Additionally,the spacing,angle,and insertion depth of two ultrasonic rods significantly affect the interaction between distinct ultrasounds.As a result,various acoustic pressure distributions and cavitation regions are obtained.The spherical rods mitigate the longitudinal and transversal attenuation of acoustic pressure and expand the cavitation volume by 53.7%and 31.7%,respectively,compared to the plate and conical rods.Increasing the input pressure will enlarge the cavitation region but has no effect on the acoustic pressure distribution pattern.The acoustic pressure ratio significantly affects the pressure distribution and the cavitation region,and the best cavitation effect is obtained at the ratio of 2:1(P15:P20).展开更多
射频识别(Radio Frequency Identification,RFID)传感技术可实现多个用户的同时低功耗无线呼吸监测,在可穿戴智慧医疗健康领域倍受关注。在概述各种呼吸监测技术基础上,重点回顾了采用柔性RFID传感技术,特别是纺织基柔性传感器监测呼吸...射频识别(Radio Frequency Identification,RFID)传感技术可实现多个用户的同时低功耗无线呼吸监测,在可穿戴智慧医疗健康领域倍受关注。在概述各种呼吸监测技术基础上,重点回顾了采用柔性RFID传感技术,特别是纺织基柔性传感器监测呼吸的基本原理和相关研究现状,比较分析了不同RFID传感方法用于呼吸监测的优缺点,最后提出了在呼吸监测领域应用纺织基RFID传感技术时面临的主要挑战和研究方向。展开更多
RFID(Radio Frequency Identification,射频识别)通过自动识别帮助机器或计算机识别对象,记录元数据或通过无线电波控制单个目标等。当RFID阅读器与Internet终端相连接时,阅读器可以根据需要全局、自动、实时地识别,跟踪和监视带有标签...RFID(Radio Frequency Identification,射频识别)通过自动识别帮助机器或计算机识别对象,记录元数据或通过无线电波控制单个目标等。当RFID阅读器与Internet终端相连接时,阅读器可以根据需要全局、自动、实时地识别,跟踪和监视带有标签的对象。研究从基于FPGA(Field Programmable Gate Array,现场可编程逻辑门阵列)的RFID阅读器三个方面入手进行阐述:整体、硬件部分和软件部分。首先论述阅读器的整体构成、天线以及数字基带结构,然后从硬件部分和软件部分细致地对阅读器进行剖析阐述,最后进行了仿真模拟。展开更多
射频识别(Radio Frequency Identification,RFID)技术是一种利用无线电波进行识别和跟踪的技术,被广泛应用于各种物品和设备的标签中,以实现自动化管理和信息追踪。深入探讨了提高RFID电力标签抗电磁干扰性能的设计方法,包括合理选择材...射频识别(Radio Frequency Identification,RFID)技术是一种利用无线电波进行识别和跟踪的技术,被广泛应用于各种物品和设备的标签中,以实现自动化管理和信息追踪。深入探讨了提高RFID电力标签抗电磁干扰性能的设计方法,包括合理选择材料、优化天线设计及采用先进的信号调制技术等策略。这些技术措施能够显著提升RFID标签在电力工器具应用中的稳定性和可靠性,从而适应复杂的电磁环境并保证电力系统的高效运行。展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51974082 and 52274377)the Fundamental Research Funds for the Central Universities(Grant No.N2209001)the Programme of Introducing Talents of Discipline Innovation to Universities 2.0(the 111 Project 2.0 of China,Grant No.BP0719037)。
文摘A transient 3D model was established to investigate the effect of spatial interaction of ultrasounds on the dual-frequency ultrasonic field in magnesium alloy melt.The effects of insertion depth and tip shape of the ultrasonic rods,input pressures and their ratio on the acoustic field distribution were discussed in detail.Additionally,the spacing,angle,and insertion depth of two ultrasonic rods significantly affect the interaction between distinct ultrasounds.As a result,various acoustic pressure distributions and cavitation regions are obtained.The spherical rods mitigate the longitudinal and transversal attenuation of acoustic pressure and expand the cavitation volume by 53.7%and 31.7%,respectively,compared to the plate and conical rods.Increasing the input pressure will enlarge the cavitation region but has no effect on the acoustic pressure distribution pattern.The acoustic pressure ratio significantly affects the pressure distribution and the cavitation region,and the best cavitation effect is obtained at the ratio of 2:1(P15:P20).
文摘射频识别(Radio Frequency Identification,RFID)传感技术可实现多个用户的同时低功耗无线呼吸监测,在可穿戴智慧医疗健康领域倍受关注。在概述各种呼吸监测技术基础上,重点回顾了采用柔性RFID传感技术,特别是纺织基柔性传感器监测呼吸的基本原理和相关研究现状,比较分析了不同RFID传感方法用于呼吸监测的优缺点,最后提出了在呼吸监测领域应用纺织基RFID传感技术时面临的主要挑战和研究方向。
文摘射频识别(Radio Frequency Identification,RFID)技术是一种利用无线电波进行识别和跟踪的技术,被广泛应用于各种物品和设备的标签中,以实现自动化管理和信息追踪。深入探讨了提高RFID电力标签抗电磁干扰性能的设计方法,包括合理选择材料、优化天线设计及采用先进的信号调制技术等策略。这些技术措施能够显著提升RFID标签在电力工器具应用中的稳定性和可靠性,从而适应复杂的电磁环境并保证电力系统的高效运行。