Development of fibre Bragg grating based strain/temperature sensing system

Investigation of polyimide coated fibre Bragg gratings for relative humidity sensing

“…These include the monitoring of civil structures, smart manufacturing, non-destructive testing, remote sensing, as well as traditional strain, pressure and temperature sensing. This type of sensor has many benefits over conventional sensors including small size, extremely low sensitivity to electromagnetic interference, good resistance to corrosion, large capacity for multiplexing, high temperature capacity, long working lifetime and excellent sensitivity to strain and temperature [1,2]. There is a need for high sensitivity moisture sensors that can operate in harsh environments.…”

Characterization of Crystal Chirality in Amino Acids Using Low-Frequency Raman Spectroscopy

“…For a given vibration at frequency ω, the oscillations can interact with light producing signals that are detectable by different methods of vibrational spectroscopy . Until recently, low-frequency vibrational (LFV) modes were detected mostly via far-infrared and THz absorption; − however, the development in recent years of volume holographic gratings (VHG) has enabled more facile use of Raman spectroscopy for this purpose. − LF-Raman possesses a number of advantages over other methods: First, the high spectral bandwidth enables recording the vibrational frequencies from 5 to 4000 cm –1 , in a single measurement, in contrast to THz and far-IR spectroscopies . Second, LF-Raman is insensitive to the presence of water, which in other methods adds a significant background signal.…”

The Deformation Measurement Technology Based on Differential Fiber Interferometer with PCI Data Acquisition System

“…So the deformation measurement for the barrel can provide effective diagnostic methods for the optimization of the structure of the launcher barrel. At present, the relative mature strain and deformation measurement methods include strain gauge measurement [1], image comparison method (such as the grid method), laser holography [2], fiber Bragg grating measurement [3], differential fiber interference measurement [4][5][6][7][8] etc. The grid measurement hasn't been paid much attention for its heavy workload and low precision.…”

“…Obviously it's difficult to measure the deformation of the non-planar barrels using the strain gauge. Fiber Bragg grating strain measurement method at present is the research focus for its high precision and relatively big measurement range [3]. However, Bragg grating fiber is only few millimeter so it can only measure the partial deformation of the barrel and has limitations in the whole radial deformation measurement of the barrel.…”