A Rail Fastener Tightness Detection Approach Using Multi-source Visual Sensor.

At present, the method of two-dimensional image recognition is mainly used to detect the abnormal fastener in the rail-track inspection system. However, the too-tight-or-too-loose fastener condition may cause the clip of the fastener to break or loose due to the high frequency vibration shock, which is difficult to detect from the two-dimensional image. In this practical application background, 3D visual detection technology provides a feasible solution.

[Online Detection System on Acetylene with Tunable Diode Laser Absorption Spectroscopy Method].

Based on tunable diode laser absorption spectroscopy (TDLAS) technique, an acetylene (C2H2) online detection system was developed by using the absorption band at the wavelength of 1.534 μm of C2H2 molecule. The sensing system consists of four modules including a distributed feedback (DFB) laser, a DFB laser driver, a gas cell with single optical path and a data processing module.

[A Methane Detection System Using Distributed Feedback Laser at 1 654 nm].

A methane (CH4) detection system based on tunable diode laser absorption spectroscopy (TDLAS) technique was experimentally demonstrated. A distributed feedback (DFB) laser around 1 654 nm, an open reflective sensing probe and two InGaAs photodiodes were adopted in the system. The electrical part of the system mainly includes the laser temperature control & modulation module and the orthogonal lock-in amplifier module.