Abstract:With the emergence of COVID-19, social distancing detection is a crucial technique for epidemic prevention and control. However, the current mainstream detection technology cannot obtain accurate social distance in real-time. To address this problem, this paper presents a first study on smartphone-based social distance detection technology based on near-ultrasonic signals. Firstly, according to auditory characteristics of the human ear and smartphone frequency response characteristics, a group of 18 kHz–23 kHz… Show more
“…At present, the flowmeter which is widely used for aircraft liquid flow measurement is mainly the turbine flowmeter. The turbine flowmeter must be in direct contact with the medium, and the pipeline needs to be cut off for installation [3] . The liquid pipeline of the aircraft is complex, the space is small, and the installation is difficult.…”
Aircraft liquid flow test is very important to evaluate the performance and state of aircraft systems, and reasonable liquid flow is the guarantee that aircraft can fly normally. Traditional flow measurement is mostly used by turbine flow meters, while ultrasonic flow measurement has the advantages of non-contact and convenient installation, which is an innovation and progress for aircraft liquid flow measurement. In the article, a time-difference ultrasonic flow measurement system based on high-precision time-to-digital conversion chip TDC-GP2 is designed, the basic principle of improved timedifference measurement is introduced, the hardware and software design of the system are discussed, and the preliminary test of ultrasonic flow measurement system is completed. The test results show that the designed ultrasonic flow measurement system has high time measurement accuracy and good stability, which provides great guidance for the test of aircraft liquid flow.
“…At present, the flowmeter which is widely used for aircraft liquid flow measurement is mainly the turbine flowmeter. The turbine flowmeter must be in direct contact with the medium, and the pipeline needs to be cut off for installation [3] . The liquid pipeline of the aircraft is complex, the space is small, and the installation is difficult.…”
Aircraft liquid flow test is very important to evaluate the performance and state of aircraft systems, and reasonable liquid flow is the guarantee that aircraft can fly normally. Traditional flow measurement is mostly used by turbine flow meters, while ultrasonic flow measurement has the advantages of non-contact and convenient installation, which is an innovation and progress for aircraft liquid flow measurement. In the article, a time-difference ultrasonic flow measurement system based on high-precision time-to-digital conversion chip TDC-GP2 is designed, the basic principle of improved timedifference measurement is introduced, the hardware and software design of the system are discussed, and the preliminary test of ultrasonic flow measurement system is completed. The test results show that the designed ultrasonic flow measurement system has high time measurement accuracy and good stability, which provides great guidance for the test of aircraft liquid flow.
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