RESUMEN
We propose a simple intrinsic Fabry-Perot interferometer (FPI) based on single-mode fiber, where a thin film is formed by arc discharge to serve as one mirror of the FPI cavity. The temperature and refractive-index (RI) characteristics of the proposed device are investigated. Experimental results show that the device can provide temperature-independent measurement of RI with a fringe-contrast sensitivity of ~72.59 dB/RIU (RI units). Meanwhile, it can also be used as a temperature sensor with a wavelength sensitivity of ~8 pm/°C. Therefore, the potential simultaneous measurement of RI and temperature could be realized by detecting the variations of fringe contrast and wavelength, respectively.
RESUMEN
OBJECTIVE: To study the chemical constituents of Ligularia macrophylla. METHODS: Isolation and purification were carried out on repeated silica gel column chromatography. The structures of the compounds were identified by physico-chemical properties and spectral analyses. RESULTS: Eight compounds were isolated and identified as kaempferol (1), 2,4'-dihydroxy-5-methoxychalcone (2), 5-hydroxy-3,4', 7-trimethoxyflavone (3), isobutyl ester terephthalic acid (4), 4-hydroxybenzaldehyde (5), mono (2-ethylhexyl) terephthalate (6), lupeol (7), beta-sitosterol (8). CONCLUSION: Compounds 1 - 7 are isolated from this plant for the first time.