Ultra-Long-Distance Hybrid BOTDA/Ф-OTDR.

In the distributed optical fiber sensing (DOFS) domain, simultaneous measurement of vibration and temperature/strain based on Rayleigh scattering and Brillouin scattering in fiber could have wide applications. However, there are certain challenges for the case of ultra-long sensing range, including the interplay of different scattering mechanisms, the interaction of two types of sensing signals, and the competition of pump power. In this paper, a hybrid DOFS system, which can simultaneously measure temperature/strain and vibration over 150 km, is elaborately designed via integrating the Brillouin optical time-domain analyzer (BOTDA) and phase-sensitive optical time-domain reflectometry (Ф-OTDR).

[Study on the alkaloids constituents from Voacanga africana].

Objective: To study the alkaloids of Voacanga africana.

Methods: The alkaloids were isolated by normal phase silica gel and Sephadex LH-20 column chromatography. Their structures were elucidated by analysis of spectroscopic data.

[Studies on the chemical constituents of Ardisia tenera].

Objective: To investigate the chemical constituents of Ardisia tenera Mez.

Methods: Compounds were isolated by normal phase silica gel, MCI GEL and Sephadex LH-20 gel column chromatography. Their structures were elucidated by analyses of spectroscopic data.