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A fiber-optic temperature sensor based on fiber tip polystyrene microsphere is proposed. The sensor structure can be formed simply by placing and fixing a polystyrene microsphere on the center of an optical fiber tip. Since polystyrene has a much larger thermal expansivity, the structure can be used for high-sensitive temperature measurement. By the illuminating of the sensor with a broadband light source and through the optical Fabry-Perot interference between the front and back surfaces of the polystyrene microsphere, the optical phase difference (OPD) or wavelength shift can be used for the extraction of temperature. Temperature measurement experiment shows that, using a fiber probe polystyrene microsphere temperature sensor with a spherical diameter of about 91.7 µm, a high OPD-temperature sensitivity of about −0.617 96 nm/°C and a good linearity of 0.991 6 were achieved in a temperature range of 20°C–70°C.

Abstract.A new process was designed for the transesterification of methyl acetate with npropanol. That is, reactive dividing-wall distillation column technology is used instead of conventional reactive distillation column and methyl acetate -methanol separation column to product n-propyl acetate and methanol. The reaction distillation process was simulated by Aspen Plus simulation software. N-propyl acetate and methanol are produced from the bottom of the main column and the sub-column, respectively. The influence of feed position of n-propanol (PROH) and methyl acetate (MEAC), reflux ratio and liquid phase distribution ratio on the heat duty of reboiler was investigated on the premise of the purity of n-propyl acetate is ensured. The simulation result shows that the new process has great advantages on capital cost saving, because not only the equipment occupancy space but also the investment in condenser are reduced.