scholarly journals Research on Non-Contact Weak Current Detection Technology

2018 ◽  
Vol 10 (04) ◽  
pp. 67-75
Author(s):  
Bo Chen ◽  
Sai Wu ◽  
Rui Wang ◽  
Changlei Liu ◽  
Jindong Lu ◽  
...  
Keyword(s):  
Weak Current ◽  
Detection Technology ◽  
Current Detection

A Novel Current Detection Technology for a Permanent-Magnet Brushless DC Motor

2010 ◽  
Vol 43 ◽  
pp. 274-278
Author(s):  
Zhan Shi Sheng ◽  
Jun Liang ◽  
Liang Jing ◽  
Dong Hua Zhang
Keyword(s):  
Voltage Drop ◽  
Current Sensor ◽  
Brushless Dc Motor ◽  
Power Electronic ◽  
Current Waveform ◽  
Brushless Dc ◽  
Detection Technology ◽  
Permanent Magnet Brushless Dc ◽  
Current Reconstruction ◽  
Current Detection

A novel technique for power electronic switch current detection is introduced in this paper, in which the current-sensor is replaced by electronics circuit. According to the principle that the magnitude of the switch current is proportional to its turned-on voltage drop, the proposed technique utilizes the method of grasping the turned-on voltage drop of the MOSFET to reproduce its current waveform. The appearances of voltage drop of the MOSFET are analyzed and the current reconstruction principles are introduced. Experimental results are given to validate the proposed technique. It has the characteristics of simplicity and inexpensiveness and is worthy of adoption.

Natural CO2 Seeps Offshore Panarea: A Test Site for Subsea CO2 Leak Detection Technology

2015 ◽  
Vol 49 (1) ◽  
pp. 19-30 ◽  
Author(s):  
Mark Schmidt ◽  
Peter Linke ◽  
Stefan Sommer ◽  
Daniel Esser ◽  
Sergiy Cherednichenko
Keyword(s):  
Near Field ◽  
Test Site ◽  
Sensor Data ◽  
Weak Current ◽  
Volcanic Gas ◽  
Membrane Inlet Mass Spectrometry ◽  
Detection Technology ◽  
Local Current ◽  
Ground Truthing

AbstractDuring RV Poseidon cruise POS469 (May 2014), the distribution of pCO2 in the near field of submarine volcanic gas flares in shallow water depths down to 50 m below sea level was continuously monitored using three different and independent methodologies. In situ nondispersive infrared (NDIR) spectrometry, pH measurements, and onboard membrane inlet mass spectrometry (MIMS) were used to determine the fate of rising CO2 bubbles and the dissolved CO2 plume patterns in a 300 × 400-m working area. The In situ sensor carrier platform, a towed video-controlled water sampling rosette, equipped with CTD sensors, guaranteed excellent ground truthing of seafloor characteristics and bubble discharge. Sensor data and near-seafloor observations indicated that the gas bubbles (<9 mm in diameter, >97 vol.% of CO2) dissolved very rapidly within the first 10 m above seafloor. Bottom water masses enriched with pCO2 (up to 1,100 μatm) show low pH values (up to 7.80) and tend to spread rather downslope west than following the measured weak current in SSE-SSW direction. The 3-D evaluation of pCO2 plume is a valuable tool to back-trace the origin of CO2 leakage when compared with local current regimes, water column CTD data, and seafloor bathymetry. Seep sites offshore Panarea can be used for studying CO2 leakage behavior and testing measuring strategies in shallow waters. Moreover, this area is a naturally designed laboratory to improve existing physicochemical and oceanographic transport models for subsea CO2 leakage.

Method of Harmonic Detection Based on the Wavelet Transform

2013 ◽  
Vol 748 ◽  
pp. 646-650
Author(s):  
Qing Yang Liang ◽  
Zhe Sun ◽  
Chen Fei Zhang
Keyword(s):  
Wavelet Transform ◽  
Active Power Filter ◽  
Active Power ◽  
Detection Methods ◽  
Harmonic Detection ◽  
Harmonic Current ◽  
Time Frequency ◽  
Power Filter ◽  
Detection Technology ◽  
Current Detection

The harmonic current detection technology is one of the key technologies of active power filter technologies. The development of the harmonic current detection technology directly determines the development of the active power filter technologies. Based on this, this paper introduces some basis concepts of wavelet transform and analyzes its time-frequency localization properties, then, describes the harmonic detection methods based on wavelet transform in terms of program building, algorithm selection and wavelet function selection. The results show that the harmonic current detection methods based on wavelet transform are able to compensate the inadequacy of Fourier transforms and can achieve the functions of detecting the steady-state and time-varying harmonic current of the grid in harmonic detection of active power filter.

The Detection System of Adaptive Electrochemical Micro Electric Current

2013 ◽  
Vol 313-314 ◽  
pp. 304-307
Author(s):  
Sheng Qian Ma ◽  
Man Hong Fan
Keyword(s):  
Signal Detection ◽  
Detection System ◽  
Current Signal ◽  
Weak Current ◽  
Large Size ◽  
Detection Circuit ◽  
Circuit Structure ◽  
Electrochemical Current ◽  
High Degree ◽  
Current Detection

The existing micro current detecting apparatus is of large size and is manual controlled. When the detected currents sensitivity is higher, however, stability will be worse. In order to solve this problem, an adaptive detection system is proposed in this paper. The system designed a micro current signal detection circuit based on OK6410 embedded with development board. The Weak current signal is collected with the high precision ADC. Automatic adjustment circuit gain is from 1 to 10000. Spectrometer wavelength size is changed in real-time. Current resolution can reach nA. The experimental results show that this system can collect the micro current effectively. The main characteristics of the system are simple circuit structure, small volume, high degree of automation, and strong reliability, and it greatly improves the anti-interference performance of the circuit. The system can not only be applied in electrochemical current detection, but also be widely used in weak signal detection.

scholarly journals A highly sensitive wide-range weak current detection circuit for implantable glucose monitoring

2016 ◽  
Vol 13 (8) ◽  
pp. 20150616-20150616 ◽  
Author(s):  
Xi Tan ◽  
Sizheng Chen ◽  
Xiao Yan ◽  
Yibo Fan ◽  
Hao Min ◽  
...  
Keyword(s):  
Glucose Monitoring ◽  
Weak Current ◽  
Highly Sensitive ◽  
Wide Range ◽  
Detection Circuit ◽  
Current Detection

Research and Implementation on Face-and-Body Detection of the Stray Current of Mine

2014 ◽  
Vol 881-883 ◽  
pp. 1706-1713
Author(s):  
Long Jiang Li ◽  
Qin Zhang ◽  
Yue Qin Qiu ◽  
Xiao Yun Zhao
Keyword(s):  
High Precision ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Stray Current ◽  
Voltage Sensors ◽  
Detection Technology ◽  
The Face ◽  
Current Detection ◽  
Hardware And Software System ◽  
Three Dimensional Space

The stray current of mine refers to the current, which flows in the way of the non-regulation line in mines. When go on the mine operations, in order to achieve stray current controlf high precision, it is necessary to carry on high precision detection of Stray current. Based on traditional “point” and “line” detection, the technology of “Face-and-Body” detection is researched and the detecting way of “Face-and-Body” technology is proposed in the paper. The “Face-and -Body” detection technology is implemented in three-dimensional space on the base of mathematical model of “Face-and-Body” .The “Face-and-Body” detection device includes in establishment of the hardware and software system, and development of the stray current detection current dual output voltage sensors, and so the size and direction of stray current are detected efficiently,thereby it improves the detection precision of the stray current.

Inspection Method of Finned Tube and Finned Heat Exchanger

2021 ◽  
Author(s):  
Ju Ding ◽  
Min Zhang ◽  
Shuhong Liu ◽  
Shenghui Wang ◽  
Jielu Wang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Eddy Current ◽  
Heat Exchangers ◽  
Finned Tube ◽  
Air Cooling ◽  
Finned Tubes ◽  
Detection Technology ◽  
Pressure Test ◽  
Current Detection

Abstract The finned tube heat exchanger is one of the earliest and most successful discoveries in the process of improving tube heat exchange. This method is still the most widely used of all kinds of tube heat transfer surface enhancement heat transfer methods. It is not only suitable for single-fin tube heat exchangers, which are widely used in power, chemical, petrochemical, air-conditioning engineering and refrigeration engineering. Conventional heat exchanger with smooth tubes can be inspected through the pressure test during the manufacturing process. Finned tubes and finned heat exchangers with inner thread structure have some difficult to pass the water pressure test. The same situation exists in regular inspections. Due to structural reasons, it is difficult to carry out regular surface inspections[1]. For these two situations, two different testing methods are required to ensure quality. This article introduces in detail the methods of inspecting finned tubes and finned heat exchangers. Hierarchical comparison of alternatives in hydrostatic testing project, and the eddy current detection technology of the finned tube under the condition of in-service air cooling. The far-field eddy current method is chosen for inspection. And by comparing the standard sample tube, it is mainly used to adjust the sensitivity of the eddy current detector and ensure the accuracy of the test results[2]. The results show that the eddy current detection technology can be more accurate and reliable. The corrosion of the finned tube under service air cooling is detected, and a reliable basis is provided for judging the use of the finned tube and finned heat exchanger[3].

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