Proposal of detection method of poor contacting on low voltage switch circuit by ultrasonic wave and diode commutation circuit

This paper provides a simple low-level unidirectional global communication method for DC microgrids, and requires no hardware modifications to the microgrid and interfacing power electronic converters. The underlying premise to this communication method is injecting low-frequency low-voltage sinusoidal components into the DC microgrid power lines. This method deviates from the common bit-level communication scheme by relating parameters and commands with certain frequency components. Communication structures are included as a basis for communication protocols, and a detection method is proposed for detecting the injected frequencies. The injection method, communication structure, and detection method are implemented on a live-scale DC microgrid.

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An improved gas kick detection method based on continuous Doppler ultrasonic wave in deep water drilling

Advances in Mechanical Engineering ◽

10.1177/1687814017715424 ◽

2017 ◽

Vol 9 (8) ◽

pp. 168781401771542

Author(s):

Quan Zhou ◽

Hui Zhao ◽

Shengnan Li ◽

Yufa He ◽

Huijie Zhang

Keyword(s):

Ultrasonic Wave ◽

Deep Water ◽

Detection Method ◽

Gas Kick ◽

Continuous Doppler

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Analysis of SMPS in Clinical Medical Equipment

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.484-485.671 ◽

2014 ◽

Vol 484-485 ◽

pp. 671-673

Author(s):

Jun Ying Zhou ◽

Nan Zhang ◽

Su Fang Kong ◽

Fu Hua Zhang ◽

Xiu Xian Guo

Keyword(s):

Power Supply ◽

Medical Equipment ◽

High Efficiency ◽

Low Voltage ◽

Voltage Level ◽

Switch Mode Power Supply ◽

Voltage Range ◽

Dc Voltage ◽

Off Time ◽

Switch Circuit

There exists low voltage in circuit of domestic and imported medical equipment and it is what we call power supply. In the past, equipment mainly uses transformer to step down the voltage of power supply. With the progress of science and technology, the technique is gradually replaced by SMPW (switch mode power supply) which is extensively applied to various types of medical equipment due to the high efficiency and wide voltage range. The mains power supply is rectified and filtered into a DC high voltage and then use the switch circuit and energy storage elements to convert them into a variety of required DC voltage output, output DC voltage level can be adjusted by changing the off time (namely Mark-Space Ratio) of switching circuit.

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Detection Technology of Foamed Mixture Lightweight Soil Embankment Based on Ultrasonic Wave Transmission Method

Advances in Materials Science and Engineering ◽

10.1155/2019/9654819 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

Shikun Pu ◽

Baoning Hong ◽

Xin Liu ◽

Fenqiang Xu ◽

Hao Shan

Keyword(s):

Ultrasonic Wave ◽

Detection Method ◽

Wave Transmission ◽

Simulation Approach ◽

Transmission Method ◽

Detection Technology ◽

Ultrasonic Parameters ◽

Test Distance ◽

Quality Diagnosis ◽

Curing Age

This study attempted to establish a process that uses the ultrasonic wave transmission method to correlate the ultrasonic parameters with the material properties of Foamed Mixture Lightweight Soil (FMLS). The results were then applied for the defect detection of the FMLS embankment. First, the ultrasonic wave velocity (UPV) and amplitude (UPA) of FMLS with different mix proportions were collected continuously from 3rd day to 45th day in the curing age. The relationships between UPV versus FMLS elastic modulus, unconfined compressive strength, and density were calibrated. The variations in the ultrasonic parameters owing to the test distance and crack width were recorded. Then, the laboratory tests were reproduced through numerical simulation approach. Finally, the reliability and accuracy of the proposed detection method for FMLS were proved and validated through on-site tests. The proposed methodology, which is simple, stable, and reliable, was found to be suitable for the quality diagnosis of FMLS embankments after construction and during operation.

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